Redistribution Of Matter Research Articles

Half a cubic hectometer mooring array of 3000 temperature sensors in the deep sea

AbstractThe redistribution of matter in the deep-sea depends on water-flow currents and turbulent exchange, for which breaking internal waves are an important source. As internal waves and turbulence are essentially three-dimensional ‘3D’, their dynamical development should ideally be studied in a volume of seawater. However, this is seldom done in the ocean where 1D-observations along a single vertical line are already difficult. We present the design, construction and successful deployment of a half-cubic-hectometer (480,000 m3) 3D-T mooring array holding 2925 high-resolution temperature sensors to study weakly density-stratified waters of the 2500-m deep Western Mediterranean. The stand-alone array samples temperature at a rate of 0.5 Hz, with precision <0.5 mK, noise level <0.1 mK and expected endurance of 3 years. The independent sensors are synchronized inductively every 4 h to a single standard clock. The array consists of 45 vertical lines 125 m long, at 9.5 m horizontally from their nearest neighbor. Each line is held under tension of 1.3 kN by a buoyancy element that is released chemically one week after deployment. All fold-up lines are attached to a grid of cables that is tensioned in a 70 m diameter ring of steel tubes. The array is build-up in harbor-waters, with air filling the steel tubes for floatation. The flat-form array is towed to the mooring site under favorable sea-state conditions. By opening valves in the steel tubes, the array is sunk and its free-fall is controlled by a custom-made drag-parachute reducing the average sinking speed to 1.3 m s-1 and providing smooth horizontal landing on the flat seafloor.

Особенности структур распада твердого раствора Cu-Ag cульфидов на месторождении Теплое (Северо-Восток России)

The authors consider features of the triple structure of Ag-Cu-S solid solution decomposition resulted from redistribution of matter in the ores of the epithermal Au-Ag Teploye deposit due to the spatial combination of volcanogenic Au-Ag mineralization, with relatively later copper porphyry. The discovery of the mckinstryite, copper-silver sulfide, permits to consider the occurrence of copper in acanthite a non-structural impurity element, while the term "cupreous acanthite" appears insufficiently substantiated. It has been suggested that the mckinstryite-jalpaite (+ acanthite) structure was formed not by the decomposition of a solid solution or the crystallization of a normal hydrothermal solution, but but in the course of solidification of the sluggish, viscous, colloid-like substance in a metastable environment under low-temperature conditions, and was accompanied by structural rearrangement of its mineral constituents.

SIMULATION OF BIOMASS DYNAMICS IN PLANKTON OF A HIGH-ALTITUDE ANDEAN TROPICAL RESERVOIR IN COLOMBIA.

The understanding of the relationships between the planktonic communities in a reservoir allows us to infer possible changes in the redistribution of matter and energy flows in these systems. This work proposes a dynamic model for the trophic network of the Riogrande II tropical reservoir, which integrates the planktonic trophic chains of detritus and grazing, limiting the prey-predator interactions by introducing the prey meeting factor (pmf). We built a dynamic model of mass balance supported by an extensive bibliographic search. The limitations of consumers and resources were represented simultaneously by means of the pmf. The data used to validate the model were compiled from previous investigations carried out in this reservoir from 2010 to 2013. The values of pmf that we found in each simulation suggest that the top predator can access its main prey in certain concentrations of total phosphorus, with a probability of encounter ranging from 9.3 % to 17.7 %. Our simulations indicate that most of the primary production is poorly used by the primary consumers in the photic zone, however, it enters in the flows of the detrital chain and supports the production of zooplankton almost entirely. According to this finding, the biomass densities obtained in the previous studies can be better explained by the causal relationships assumed in this model.

A linked-scale coupled model of mass erosion and redistribution in plasma-exposed micro-foam surfaces

Surface evolution due to exposure to harsh environments is of importance in many scientific and technological applications. In plasma-exposed materials, the surface receives charged particles from the plasma, leading to a series of processes that drive the system far from equilibrium and may lead to the severe deterioration of the surface properties. Although surface morphological changes are driven by atomic collisions taking place over picoseconds and nanometers, these processes result in mass loss and redistribution of matter over much larger length and time scales. This necessitates a multi-scale approach capable of capturing the range of processes linking primary atomic collision events with engineering-level surface geometry changes. In this paper, we develop a computational model to simulate the morphological evolution and effective erosion rate of micro-architected tungsten foams during low-energy plasma ion bombardment. The model acts on several length scales, with the energy and angular dependence of the sputtering yield of flat tungsten surfaces determined using the SRIM code based on the binary collision approximation. This information is introduced into a low-fluence, short-term Monte Carlo raytracing model, and further into a high-fluence, long-term particle transport model. In the latter, material particles representing billions of atoms are described in a digitized 3-D representation of the foam structure from X-ray tomography data, and are sputtered off and redeposited using the atomistic information. We show that the redeposition of sputtered atoms leads to partial self-healing in the bottom layers with a sharp reduction in the sputtering coefficient of low density foams, roughly 25% of the solid W value. This is in qualitative agreement with recent experiments on low porosity W structures. At high fluence, the foam structure degrades considerably as there are fewer ligaments available to recapture sputtered atoms and, consequently, the sputtering rate increases again.

Characteristics of topographic submesoscale eddies off the Crimea coast from high-resolution satellite optical measurements

Long-term arrays of satellite optical measurements of Landsat-5,7,8 and Sentinel-2 were used to describe the characteristics of submesoscale eddy (SE) dynamics in different parts of the Crimean coast: their geometric and kinematic characteristics, the main sites and mechanisms of formation, and impact on the redistribution of suspended matter. The dynamic characteristics of SE were computed on the base of the 4D variational assimilation method from the pair of consecutive Landsat-8/Sentinel-2 images. The orbital velocity of submesoscale cyclonic eddies (SCE) with a diameter of 1 km reaches 0.15 m/s, indicating the cyclostrophic balance with a high Rossby number (RO) exceeding 2. Submesoscale cyclones were detected much more frequently than the usually larger submesoscale anticyclones. High-resolution satellite imagery gives a possibility to observe complex submesoscale dynamic processes, such as the generation of chains of SCE, large cyclones behind the capes consisting of densely packed arrays of SCEs, topographic submesoscale anticyclones with a number of attached SCEs, mushroom-like current structures, and frontal SE. Despite the diversity of the processes considered, several basic mechanisms of formation of submesoscale eddies can be identified on the basis of satellite data: (1) Separation of the boundary current, often wind-driven, behind the capes; (2) barotropic instability due to the horizontal shear on the coastal periphery of mesoscale anticyclones or alongshore currents; (3) formation of the mushroom-like structure due to the interaction of offshore currents with deep waters near the capes or due to offshore winds; and (4) frontal instabilities on the coastal upwelling. The results of the analysis were used to create a scheme of the spatial variability of submesoscale processes near the Crimean coast and compare it to the results of the high-resolution modeling. The model was able to describe the main areas of SE formation, which was located near the major capes. It provides additional data about SE generation near the rocky capes of the South Crimea, where satellite data was limited by the absence of optical tracers.

The role of biota in soil profile formation and soil functioning: new materials and interpretation of well-known facts and existing concepts

Review of the monograph by A.D. Fokin and S.P. Torshin “Plants in the Life of Soils and Terrestrial Ecosystems. Nontraditional Approaches and Solutions on the Behavior of Biologically Significant Elements” published in 2020 by Lap Lambert Academic Publishing, ISBN 978-620-2-53005-7. In the monograph by A.D. Fokin and S.P. Torshin, the reader finds an original and not always traditional for soil scientists, consideration and discussion of a number of fundamental problems of the development of a soil profile and modern soil functioning and of the role of plants and microorganisms in these processes. The authors of the monograph make us think about the validity of some generally accepted concepts and hypothesis, especially those concerning transport flows of matter in soils and their modeling. Attention is drawn to the usually underestimated role of the uplifting – ascending fluxes of matter along the conductive systems of plants, and to the localization of living roots and organic residues in soils. The latter factor plays an important role in the development of intrahorizontal differentiation of the soil material and in the root nutrition of plants. The great advantage of the book is the availability of abundant experimental material obtained by unique methods developed by the authors, simple and effective, which have no analogues in the world literature. Application of these methods, allows, in particular, determining the lifetime of the aggregate in soddy-podzolic soils and establishing the trends in the root uptake of radionuclides from the surface and from the inner part of peds. In the end a general conclusion is formulated that in the course of modern soil functioning, the soil-profile redistribution of matter is performed mainly within the limits of the biological cycle of elements. Many of the problems and ideas discussed in the monograph go far beyond the soil science, therefore the book is of great interest for a wide range of specialists in environmental and plant sciences, in agricultural chemistry, forestry and in various branches of geosciences.

FEATURES OF ECOLOGICAL GEOMORPHOMETRY AS A PROSPECTIVE FIELD OF STUDY, ITS MAIN CONCEPTS AND METHODS

Abstract. The main concepts and methods of ecological geomorphometry as a research field aimed at studying relationships between terrain morphometric characteristics and ecological factors and processes are reviewed in the paper. The progress in this research field has been conditioned by the propagation of high-resolution digital elevation models in free access and of methods of their digital analysis, namely: the calculation of derivative quantitative characteristics (attributes and indices) of terrain and the statistical models of analyzing the relationships between the latter and the ecological properties and factors (those relevant for a certain ecological subject). A peculiar feature of ecological approach to regarding terrain (its morphology) is subjectcentrism (that is, regarding it from a point of view of a certain subject). The subject of ecological relationships can be living entities (populations, species, communities) as well as a human, social entities, economy and its branches. Three main concepts of ecological geomorphometry are put forward: terrain attributes (relatively simple quantitative characteristics of terrain form that characterize its geometry and some elementary physical processes); topographic indices (quantitative surrogates for some complex physical or biophysical processes of ecological significance); morphotops (spatial units that are distinguished by terrain morphology, using criteria of ecological homogeneity relevant from a viewpoint of a certain ecological subject). Morphotops can be distinguished with different level of detail (and, as a result, with different characteristic dimensions), relative to the study aim, to the geographic features of the area, and to the available data and the methods of their analysis. While morphotops are distinguished with strictly defined quantitative morphometric parameters (terrain attributes, topographic indices), this enables using formalized methods with their advantages of reproducibility and possibility of automatizing. In our studies aimed at morphotop mapping for a small area in the hilly terrain of Davydiv range near Lviv and for a larger area in the central part of Ukrainian Carpathians, morphotops delineation was based on topographic indices that characterize insolation level (solar radiation incidence on terrain elements of different aspect and slope values), lateral redistribution of water on slopes and redistribution of solid matter by washout on slopes. Morphotops were distinguished with cluster analysis method, which allows to distinguish natural groupings of data in the attribute space. Presetting different number of clusters to be distinguished, morphotopes can be distinguished with different levels of detail, larger number of clusters corresponding to more homogenous morphotops with smaller characteristic sizes. Key words: ecological geomorphology, ecological geomorphometry, morphotops, terrain attributes, topographic indices.

Multistage Thrust and Nappe Tectonics in the Southeastern Part of East Sayan and Its Role in the Formation of Large Gold Deposits

Abstract ––Comprehensive studies of structural geology and metallogeny, taking into account the authors’ previous works started as early as the last century, have shown that the southeastern part of East Sayan formed mainly in the Neoproterozoic–early Paleozoic in the settings of multistage thrust and nappe tectonics and tectonomagmatic restructuring of autochthonous and overthrust allochthonous oceanic (ophiolitic), island arc, and ocean-marginal terranes as well as amalgamation of accretion–collision and postcollisional igneous complexes that formed during the opening and subsequent closure of the Paleoasian Ocean marginal structures. In the middle and late Paleozoic, active intraplate volcanic and plutonic processes continued in the thrust/overthrust fault setting, which led to the formation of new dome-shaped nappe structures and the redistribution of ore matter (gold etc.) in large mineral deposits. The final structure of the East Sayan region formed during the late Cenozoic as a result of mountain uplifting and volcanic eruptions, including those in the valley of the Zhombolok River.

New Strategies for Engineering Tensile Strained Si Layers for Novel n-Type MOSFET

We report a novel approach for engineering tensely strained Si layers on a relaxed silicon germanium on insulator (SGOI) film using a combination of condensation, annealing, and epitaxy in conditions specifically chosen from elastic simulations. The study shows the remarkable role of the SiO2 buried oxide layer (BOX) on the elastic behavior of the system. We show that tensely strained Si can be engineered by using alternatively rigidity (at low temperature) and viscoelasticity (at high temperature) of the SiO2 substrate. In these conditions, we get a Si strained layer perfectly flat and free of defects on top of relaxed Si1-xGex. We found very specific annealing conditions to relax SGOI while keeping a homogeneous Ge concentration and an excellent thickness uniformity resulting from the viscoelasticity of SiO2 at this temperature, which would allow layer-by-layer matter redistribution. Remarkably, the Si layer epitaxially grown on relaxed SGOI remains fully strained with -0.85% tensile strain. The absence of strain sharing (between Si1-xGex and Si) is explained by the rigidity of the Si1-xGex/BOX interface at low temperature. Elastic simulations of the real system show that, because of the very specific elastic characteristics of SiO2, there are unique experimental conditions that both relax Si1-xGex and keep Si strained. Various epitaxial processes could be revisited in light of these new results. The generic and simple process implemented here meets all the requirements of the microelectronics industry and should be rapidly integrated in the fabrication lines of large multifinger 2.5 V n-type MOSFET on SOI used for RF-switch applications and for many other applications.

Top-down controls on nutrient cycling and population dynamics in a model estuarine photoautotroph-heterotroph co-culture system.

Viral lysis and protistan grazing are thought to be the major processes leading to microbial mortality in aquatic environments and thus regulate community diversity and biogeochemical cycling characteristics. Here, we studied nutrient cycling and bacterial responses to cyanophage-mediated photoautotroph lysis and ciliate predation in a model Synechococcus-heterotroph co-culture system. Both viral lysis and Euplotes grazing facilitated the transformation of organic carbon from biomass to dissolved organic matter with convention efficiencies of 20%-26%. The accumulation of ammonium after the addition of phages and ciliates suggested the importance of recycled NH4+ occurred in the interactions between Synechococcus growth and heterotrophic bacterial metabolism of photosynthate. The slower efficiency of P mineralization compared to N (primarily ammonium) indicated that P-containing organic matter was primarily integrated into bacterial biomass rather than being remineralized into inorganic phosphate under C-rich conditions. In the cyanophage addition treatment, both Fluviicola and Alteromonas exhibited rapid positive responses to Synechococcus lysing, while Marivita exhibited an apparent negative response. Further, the addition of Euplotes altered the incubation system from a Synechococcus-driven phycosphere to a ciliate-remodelled zoosphere that primarily constituted grazing-resistant bacteria and Euplotes symbionts. Top-down controls increased co-culture system diversity and resulted in a preference for free-living lifestyles of dominant populations, which was accompanied by the transfer of matter and energy. Our results indicate top-down control was particularly important for organic matter redistribution and inorganic nutrient regeneration between photoautotrophs and heterotrophs, and altered bacterial lifestyles. This study consequently sheds light on marine biogeochemical cycling and the interaction networks within these dynamic ecosystems.

White-tailed Deer Fecal Matter Distribution and Nutrient Contribution in Tallgrass Prairie

Herbivores can have nonconsumptive effects on ecosystems, including the redistribution of nutrients in their waste. In tallgrass prairie bison (Bison bison) historically increased soil nitrogen availability via labile waste deposits. White-tailed deer (Odocoileus virginianus) are now the dominant native large herbivore in prairie and have been shown to consume higher nutrient-content plants than those preferred by bison. Deer are also edge-dwelling species that reuse the trails they make as they move and browse throughout the prairie. Therefore, deer may differ from bison in their spatial patterns of nutrient content and redistribution of fecal matter. We examined the nutrient content and spatial distribution of deer pellets by measuring the number of deer pellet piles along deer trails and transects that were systematically placed at the forest border and in open prairie. We also measured the nitrogen content of deer pellets. White-tailed deer pellets had twofold greater nitrogen concentrations (3.43% N and 40.8% C) compared to values reported for bison fecal matter. Deer pellet piles were more concentrated on deer trails compared to the transects, resulting in fourfold greater N inputs on deer trails compared to areas off of trails. As a result, White-tailed deer have the potential to create patches of increased nutrient availability through their clumped distribution of nutrient rich fecal matter, with potential consequences for prairie plant communities.

Decomposition of black pine (Pinus nigra J. F. Arnold) deadwood and its impact on forest soil components

Deadwood decomposition is a complex and dynamic process with large implications for biogeochemical cycling of carbon (C) and nitrogen (N) in forest soil and litter. Moreover, it affects functional and structural diversity of fungal and bacterial communities in these components. Mesocosms with deadwood blocks at progressive decay classes were set in a black pine forest and incubated for 28 months in the field with the aim to assess the impact of deadwood decomposition on i) CO2, CH4 and N2O fluxes; ii) C and N pools and allocation among deadwood, litter and soil; iii) the fungal and bacterial structural diversity and activity.CO2, CH4 and N2O fluxes from deadwood were monitored throughout the field incubation; deadwood biomass loss and decay rate for each decay class were calculated. The stock of C and N, enzyme activities, fungal and bacterial communities in deadwood, litter fractions (fresh, fragmented and humified) and soil at two depths were measured.Emissions of CO2 and CH4 increased over the deadwood decomposition advancement and the decay reached the maximum rates in the last decomposition classes. N2O fluxes were low and showed either production (prevalent in the first year) or consumption. Independent of the decay class, 20% of C stored in deadwood was lost as CO2 in the atmosphere, whereas 32% was transferred to the fragmented and humified litter fractions in the last decay class. A corresponding increase of cellulose and hemicellulose degrading enzymes was found in deadwood, also favored by substrates accessibility through fragmentation and successional changes in fungal and bacterial communities.Deadwood, litter fractions and soil components were clearly distinguished in terms of chemical and microbiological properties and activities. Fragmented and humified litter fractions were the only components responsive to the advanced stage of deadwood decomposition, being directly affected by the physical redistribution of fragmented organic matter.

Long-term response of tropical Andisol properties to conversion from rainforest to agriculture

Short-term changes in tropical rainforest soil properties and their impact on C cycling following land-use conversion to agriculture have received intensive study. However, long-term, land-use changes have not been explored for tropical Andisols, whose high carbon stocks and several distinctive properties may differ in their response to land-use conversion. Thus, the primary objective of this study was to assess changes in selected soil properties of Andisols in response to long-term (>100 years) changes of land use from tropical rainforests to agriculture. Soils were sampled by horizon to a depth of 110–140 cm in pine forests (PF), tea plantation (TP) and horticultural crops with either intensive cultivation (IH) or bare fallow (FH) cropping systems. Selected physical, chemical and biological soil properties were characterized, including microbial biomass carbon (MBC) and laboratory CO2 mineralization rates. Results showed that land-use change from rainforest to agriculture resulted in increased soil bulk density and meso/micropores that contributed to increased plant-available water retention capacity. Soil carbon and nitrogen stocks in the upper 1 m of soil were higher in agricultural soils (25–29 kg C m−2; 1.7 – 2.3 kg N m−2) than pine forest soil (17 kg C m−2; 1 kg N m−2) with a redistribution of organic matter from topsoil to subsoil horizons. Organic matter quality was also affected by land-use conversion with the horticultural soils having lower rates of carbon mineralization per unit soil carbon (PF > TP > IH > FH) and lower microbial biomass, especially in topsoil horizons. The MBC sharply decreased in the topsoil horizon due to land-use change from forest (330 mg kg−1) to agricultural production (<118 mg kg−1). The intensive horticultural soil receiving recent additions of horse manure had higher extractable mineral N (especially NO3), reduced P fixation, increased available P, higher pH, and higher concentrations of exchangeable base cations (Ca2+, Mg2+ and K+) and micronutrients (Zn, Mn and Cu). The Andisols in this study demonstrated strong resilience to long-term degradation of soil properties following conversion from rainforest to agronomic land use. Further, this study demonstrates the ability of these Andisols to sequester additional C upon conversion to selected agriculture practices, thereby providing a positive impact on C mitigation.

Micromorphological features of soils of semidesertic solonetzic complexes under different herbaceous communities with the participation of fodder plant Kochia prostrata (Caspian lowland)

The aim of the study was to research the relationship of chemical and micromorphological properties of soils with the growth ofKochia prostrata. The objects of study were the soils on natural pastures of the North-Western part of the Caspian lowland. It was laid 4 soil pits (soils – light solonetz, solonetzic chestnut) with the maximum penetration depth of the main mass of roots of the studied plants.K. prostratais a very plastic forage species that can grow on soils with a wide range of morphological properties, different salt content and their chemical composition. It is revealed that on the background of almost the same content of humus and high content of exchangeable magnesium micromorphological features represent the different degree of manifestation of primary pedogenic processes – humus accumulation, leaching of soluble salts, gypsum accumulation, carbonate enrichment, solonetzization. Despite the different content of exchangeable sodium, in all soils there are fresh clay or humus-clay illuvial coatings, indicating the manifestation of the modern eluvial-illuvial redistribution of fine matter (lessivage or illimerization).

Carbon Isotope Discrimination and Water-Use Efficiency in Crotalaria Cover Crops under Moderate Water Deficit

The legume species Crotalaria juncea and Crotalaria spectabilis, used as cover crops (CC) in tropical and temperate zones, are being evaluated in Uruguay where their productive potential may be limited by periods of summer water deficit. In this study, C. juncea and C. spectabilis were sown in pots with soil as a substrate. After substantial growth (20 days), two different treatments of water (80% or 50% of field capacity) were imposed on the plants during 30 days, and later water was restored during 40 days. Afterward, the dry matter produced and total evapotranspired water was determined in all plants. Also, water-use efficiency (WUE) was determined using a gravimetric technique and by carbon isotope analysis (Δ13C). Dry matter production of C. spectabilis was 1.7 times higher than that of C. juncea and both legumes species tolerated a moderate water deficit, which did not affect the redistribution of dry matter between the shoot and root. A negative linear relationship (r = 0.8; p < 0.0001) was found between the WUE and Δ13C in both species. In this study, the use of 13C to estimate WUE in Crotalaria spectabilis and Crotalaria juncea was validated for the first time. This strategy allowed us to recommend the use of Crotalaria spectabilis as a cover crop in conditions of moderate water deficit in a soil with a shallow A horizon.

Unique role of pore water in lateritic bauxite formation, Republic of Guinea

Results of the hydrogeochemical study of bauxite-bearing lateritic mantles of the Futa Djallon-Mandingo Province, West Africa, have allowed us to first characterize the pore water of vadose and infiltration hydrogeological zone. Abundances of major components (aluminum and iron) of the water are shown to be few orders higher than are those typical of the other waters of lateritic mantles. The pore water is proved to be a major factor of matter redistribution over any bauxite-bearing lateritic profile.

40Ar/39Ar Age of Gold Ore Metasomatites of the Albyn Deposit, Mongol–Okhotsk Fold Belt

The paper reports the results of 40Ar/39Ar geochronological studies of the muscovite–quartz–albite metasomatites of the ore bodies and host rocks of the Albyn deposit located in the Selemdzha–Kerbi structural zone of the eastern part of the Mongol–Okhotsk Fold Belt. To a first approximation, the age of the hydrothermal ore process responsible for the formation of the Albyn deposit can be estimated within an interval of 131–130 Ma. At the same time, we cannot exclude the existence of an earlier stage of this process at ~135 Ma, although this assumption requires further substantiation. A close age estimate (~134–130 Ma) was obtained earlier for the ore metasomatites of the Malomyr deposit located in the same structural zone. There are no data on the magmatic manifestations of close age within the considered region, which makes it impossible to relate the ore mineralization of the Albyn deposit with magmatic processes. At the same time, the age of the thermal event superimposed on the host rocks of the Afanasiev Formation is 131 ± 3 Ma, which likely indicates the regional nature of this event. We suggest that a significant role in the mobilization, redistribution of ore matter, and formation of the Albyn deposit was played by large-scale deformations accompanied by hydrothermal activity.

Effects of exogenous 6-BA on the yield of wheat after rice in the Jianghan Plain under diffe-rent shading treatments

The long duration of rainy weather in the Jianghan Plain leads to low light stress to wheat during the growing season. We examined the effects of shading at booting stage (S1) and anthesis (S2) on grain yield and physiological traits of two main wheat cultivars in Jianghan Plain, Zhengmai 9023 (ZM 9023) and Yangmai 23 (YM 23). 6-BA was sprayed before shading treatment (S1+6-BA, S2+6-BA) to explore the mitigation effect of low light stress by 6-BA. The results showed that 45% shading of full solar radiation at booting and anthesis stages significantly reduced grain yield, with greater effect at anthesis than that at the booting stage. Dry matter accumulation of grain during 14-21 days after anthesis was significantly decreased by shading. Shading at both growth stages reduced dry matter accumulation at maturity and changed the proportion of dry matter redistribution in vegetative organs. Consequently, grain yield was more dependent on the storage of photosynthetic assimilates of vegetative organs before anthesis, which resulted in a decline of grain yield in shading treatment. The grain yield of spraying 6-BA before anthesis was significantly greater than that of shading treatment, suggesting exogenous application of 6-BA could delay the senescence of flag leaf, grain filling rate and grain weight to mitigate the negative effect of shading. In addition, spraying 6-BA increased dry matter accumulation in the shading treatment at anthesis, and the translocation of post-anthesis assimilates. Grain weight of S2+6-BA was higher than that with S2, which ultimately increased grain yield as compared to the shading treatment. In conclusion, the negative impact of shading on wheat grain yield at anthesis was greater than that at booting stage. The application of exogenous 6-BA before shading at anthesis could mitigate yield loss of the shading treatment.

Soliton interactions of a variable-coefficient three-component AB system for the geophysical flows

Geophysical flows consist of the large-scale motions of the ocean and/or atmosphere. Researches on the geophysical flows reveal the mechanisms for the transport and redistribution of energy and matter. Investigated in this paper is a variable-coefficient three-component AB system for the baroclinic instability processes in geophysical flows. With respect to the three wave packets as well as the correction to the mean flow, bilinear forms are obtained, and one-, two- and [Formula: see text]-soliton solutions are derived under some coefficient constraints via the Hirota method. Soliton interaction is graphically investigated: (1) Velocities of the [Formula: see text] and [Formula: see text] components and amplitude of the [Formula: see text] component are proportional to the parameter measuring the state of the basic flow, where [Formula: see text] is the [Formula: see text]th wave packet with [Formula: see text] and [Formula: see text] is related to the mean flow; Amplitudes of the [Formula: see text] components decrease with the group velocity increasing; Parabolic-type solitons, sine-type solitons and quasi-periodic-type two solitons are obtained; For the [Formula: see text] component, solitons with the varying amplitudes and dromion-like two solitons are shown; (2) Three types of the breathers with different interaction periods and numbers of the wave branches in a wave packet are analyzed; (3) Bound states are depicted; (4) Compression of the soliton is presented; (5) Interactions between/among the solitons and breathers are also illustrated.

Particulate Matter Fluxes in a Mediterranean Mountain Forest: Interspecific Differences Between Throughfall and Stemflow in Oak and Pine Stands

AbstractIn forested areas, canopies play an important role in the partitioning of rainfall. During this process there is also a redistribution of particulate matter (PM) that is deposited from the atmosphere on vegetative surfaces and transported to soil layers by throughfall and stemflow. We collected samples of rainfall, throughfall, and stemflow from two different forest plots (pine and oak) in a Mediterranean mountainous area and analyzed the amount and size distributions of PM (0.45 μm &lt; PM &lt; 500 μm). The exploration of backward trajectories revealed that PM content varied significantly. This depended on the origin of the air mass, with Atlantic fronts transporting less PM in the atmosphere than North African dust intrusions, which added disproportionate inputs of PM. Overall, throughfall provided the largest proportion of incoming PM under trees, but, at the base of each tree, stemflow led to a localized input of water that was more PM enriched than water through open precipitation or throughfall. Interspecific differences in PM fluxes were noted with pines retaining more PM in their crowns than oaks. Furthermore, the presence of leaves on oak increased the size and the amount of particulates released by throughfall. The PM in stemflow was smaller and rounder than in throughfall. This study adds to our understanding knowledge of the processes that control the deposition and distribution of PM delivered to forest soils, a fraction that is often ignored in studies of nutrient and energy fluxes in ecosystems.