Complicated Distribution Pattern Research Articles

Study on the Preferential Flow Characteristics under Different Precipitation Amounts in Simian Mountain Grassland of China

Understanding the response of preferential flow paths to water movement is an important topic in soil hydrology. However, quantification of the complicated distribution patterns of preferential flow paths remains poorly understood. Therefore, dye experiments were conducted to investigate preferential flow characteristics under three different precipitation amounts (20, 40 and 60 mm, numbered as the G20, G40 and G60, respectively) in Simian Mountain grassland, Chongqing province, China. O-ring statistics were used to analyze the spatial distribution characteristics and the spatial correlation of preferential flow paths. Results revealed that precipitation could promote dye tracer infiltration into deeper soils, reaching the maximum depth of 55 cm in G60. The number of preferential flow paths in G60 plots was 3.0 and 7.4 times greater than those of G40 and G20, respectively. Structural distribution of the preferential flow paths showed a gradually clumped pattern with the increase of precipitation, which was conducive to enhancing the correlation between preferential flow paths in each pore size range. These results could expand our understanding of the effects of precipitation on the characteristic of preferential flow paths in grassland, which is helpful to evaluate the water movement in the study area.

Behavior of the 238U, 235U, and 234U isotopes at weathering of volcanic rocks with u mineralization: a case study at the Tulukuevskoe deposit, Eastern Transbaikalia

The trend fractionation of the 238U and 235U isotopes and the extent of this process at the oxidative weathering of uranium minerals were evaluated by studying the variations in the U isotope composition of rocks, minerals, and fracture waters sampled in the quarry of the broadly known Tulukuevskoe uranium deposit in the Streltsovskoe ore field, eastern Transbaikalia. In the rock block in question, fine uranium minerals disseminated in the rocks were weathered under the effect of oxidizing fracture waters. Uranium isotope composition was measured in 22 water samples, eleven samples of the mineralized rocks, and eight uranium minerals. High-precision (±0.07‰, 2SD) measurements of the 238U/235U were carried out by MC-ICP-MS, using a 233U–236U double spike. The results involve the 238U/235U and 234U/238U ratios and the overall range of the δ238U variations determined in the rocks and waters (from –0.13 to –1.0‰ and from –0.22 to –0.59‰, respectively). Interaction between the waters and rocks induces U(IV) → U(VI) oxidation, U(VI) transfer into the aqueous phase, and 0.15–0.28‰ enrichment of U dissolved in the water in the 235U isotope. When the pitchblende is replaced by U(VI) minerals, the 238U and 235U isotopes also fractionate with ~0.3‰ enrichment of the younger U(VI) mineral phases in the light 235U isotope. The 238U/235U and 234U/238U ratios are proved to correlate, and hence, the fractionation of the 238U and 235U isotopes and the enrichment of the aqueous phase in the light 235U isotope proceed simultaneously with the well known shift in equilibrium the 238U–234U system with the accumulation of excess amounts of the 234U in the aqueous phase. Uranium leaching from uranium minerals, which is associated with the enrichment of the aqueous phase in excess amounts of the 234U isotope, can be viewed as a process that controls isotope fractionation in the 238U–235U system. This should be taken into account in describing the fractionation mechanism of the 238U and 235U isotopes at U(IV) → U(VI) oxidation. The fractionation of the 238U and 235U isotopes, which results in the isotopic "lightening" of U in the aqueous phase, largely controlled the complicated distribution pattern of the 238U/235U ratio in the quarry. In addition to isotope fractionation, this distribution was likely also affected by isotope exchange between uranium dissolved in the water and uranium in the finely dispersed minerals. The isotopically light uranium of the water could participate in forming U(VI) minerals at lower levels of the quarry.

Behavior of the 238U, 235U, and 234U Isotopes at Weathering of Volcanic Rocks with U Mineralization: A Case Study at the Tulukuevskoe Deposit, Eastern Transbaikalia

The trend fractionation of the 238U and 235U isotopes and the extent of this process at the oxidative weathering of uranium minerals were evaluated by studying the variations in the U isotope composition of rocks, minerals, and fracture waters sampled in the quarry of the broadly known Tulukuevskoe uranium deposit in the Streltsovskoe ore field, eastern Transbaikalia. In the rock block in question, fine uranium minerals disseminated in the rocks were weathered under the effect of oxidizing fracture waters. Uranium isotope composition was measured in 22 water samples, eleven samples of the mineralized rocks, and eight uranium minerals. High-precision (±0.07‰, 2SD) measurements of the 238U/235U were carried out by MC-ICP-MS, using a 233U–236U double spike. The results involve the 238U/235U and 234U/238U ratios and the overall range of the δ238U variations determined in the rocks and waters (from –0.13 to –1.0‰ and from –0.22 to –0.59‰, respectively). Interaction between the waters and rocks induces U(IV) → U(VI) oxidation, U(VI) transfer into the aqueous phase, and 0.15–0.28‰ enrichment of U dissolved in the water in the 235U isotope. When the pitchblende is replaced by U(VI) minerals, the 238U and 235U isotopes also fractionate with ~0.3‰ enrichment of the younger U(VI) mineral phases in the light 235U isotope. The 238U/235U and 234U/238U ratios are proved to correlate, and hence, the fractionation of the 238U and 235U isotopes and the enrichment of the aqueous phase in the light 235U isotope proceed simultaneously with the well known shift in equilibrium the 238U–234U system with the accumulation of excess amounts of the 234U in the aqueous phase. Uranium leaching from uranium minerals, which is associated with the enrichment of the aqueous phase in excess amounts of the 234U isotope, can be viewed as a process that controls isotope fractionation in the 238U–235U system. This should be taken into account in describing the fractionation mechanism of the 238U and 235U isotopes at U(IV) → U(VI) oxidation. The fractionation of the 238U and 235U isotopes, which results in the isotopic “lightening” of U in the aqueous phase, largely controlled the complicated distribution pattern of the 238U/235U ratio in the quarry. In addition to isotope fractionation, this distribution was likely also affected by isotope exchange between uranium dissolved in the water and uranium in the finely dispersed minerals. The isotopically light uranium of the water could participate in forming U(VI) minerals at lower levels of the quarry.

Application of Landscape Pattern Analysis to Quantitatively Evaluate the Spatial Structure Characteristics of PreferentialFlow Paths in Farmland

Abstract. The distribution of soil preferential paths is a natural process with highly spatiotemporal variability. However, an adequate analysis method to evaluate the spatial structures of soil preferential paths from the viewpoint of ecology has not yet been developed. Hence, the quantification of the complicated distribution patterns of soil preferential paths and their relation to biota activities from the ecological perspective remains elusive. This article presents a new method that combines the image processing technology of morphology and spatial pattern analysis (i.e., quantitative parameters W i , M i , U i , and g(r) function) of landscape ecology to quickly observe and quantify the spatial distribution characteristics of preferential flow paths. The study was conducted on soybean fields in the Three Gorges Reservoir Areas in China. Results demonstrated that the proposed method can describe the spatial connectivity, development degree, and rapid water conductivity of different preferential flow paths (paths of 2.5-5.0 mm were the highest, whereas paths of 1.0-2.5 mm were the lowest). All the preferential flow paths, except for the paths of 1.0-2.5 mm (random distribution pattern), mainly demonstrated a gradual tendency to follow a clumped distribution pattern and community structure relative to soil depth. In addition, all the paths showed low spatial complexity because of their uniform composition relative to soil depth. Soil intra-structure ( 5.0 mm) and plant roots effectively influenced the distribution patterns and formation of the preferential paths in the deep farmland soil. Plant roots, in particular, significantly influenced the formation and distribution of the preferential flow paths of 1.0-2.5 mm in the soybean field. Compared with existing methods (e.g., dye tracing, resin impregnation, water breakthrough curve analysis, and computed tomography technique), the proposed method can provide more significant spatial structure information from an ecological perspective. Such information can help expand our understanding of the spatial structures of preferential flow paths and the underlying ecological formation processes in soil ecosystems. The method is also effective, convenient, rapid, and economical when used to the study the spatial structures of soil preferential paths at different field scales for soil management.

A rational elasto‐plastic spatially curved thin‐walled beam element

AbstractTorsion is one of the primary actions in members curved in space, and so an accurate spatially curved‐beam element needs to be able to predict the elasto‐plastic torsional behaviour of such members correctly. However, there are two major difficulties in most existing finite thin‐walled beam elements, such as in ABAQUS and ANSYS, which may lead to incorrect predictions of the elasto‐plastic behaviour of members curved in space. Firstly, the integration sample point scheme cannot capture the shear strain and stress information resulting from uniform torsion. Secondly, the higher‐order twists are ignored which leads to loss of the significant effects of Wagner moments on the large twist torsional behaviour. In addition, the initial geometric imperfections and residual stresses are significant for the elasto‐plastic behaviour of members curved in space. Many existing finite thin‐walled beam element models do not provide facilities to deal with initial geometric imperfections. Although ABAQUS and ANSYS have facilities for the input of residual stresses as initial stresses, they cannot describe the complicated distribution patterns of residual stresses in thin‐walled members. Furthermore, external loads and elastic restraints may be applied remote from shear centres or centroids. The effects of the load (and restraint) positions are important, but are not considered in many beam elements. This paper presents an elasto‐plastic spatially curved element with arbitrary thin‐walled cross‐sections that can correctly capture the uniform shear strain and stress information for integration, and includes initial geometric imperfections, residual stresses and the effects of the load and restraint positions. The element also includes elastic restraints and supports, which have to be modelled separately as spring elements in some other finite thin‐walled beam elements. Comparisons with existing experimental and analytical results show that the elasto‐plastic spatially curved‐beam element is accurate and efficient. Copyright © 2006 John Wiley & Sons, Ltd.

Colonization history of the Japanese water shrewChimarrogale platycephala, in the Japanese Islands

To evaluate the intraspecific evolutionary history and local differentiation of the Japanese water shrewChimarrogale platycephala (Temminck, 1842), we an a lyzed the mitochondrial cytochromeb (Cytb) sequence divergence for samples from 55 localities in the Japanese is lands of Honshu and Kyushu. According to phylogenetic trees based on theCytb data, there were fourCytb haplotype lineages, which showed rough affinities with geographic areas, namely, Eastern/Central Honshu, the Kinki District of Western Honshu, the Chugoku District of Western Honshu, and Kyushu. However, in the alpine areas of the boundary between the Kinki and Chugoku Districts, complicated distribution patterns of theCytb haplotypes were revealed. Considering the present data and geological history in the Quaternary, we hypothesized the following evolutionary scenario. First, differ entiation and division into four primary ancestral geographic colonies of the shrews occurred in hypothetical refugia in the mid — late Pleistocene. Subsequently, rapid expansion occurred and caused the complicated distribution patterns of theCytb haplotypes in the boundary areas owing to the complex topography during the late stage of the Quaternary.

MICRO3D: COMPUTER PROGRAM FOR THREE-DIMENSIONAL RECONSTRUCTION, VISUALIZATION, AND ANALYSIS OF NEURONAL POPULATIONS AND BRAIN REGIONS

This article presents a computer program, Micro3D, designed for 3-D reconstruction, visualization, and analysis of coordinate-data (points and lines) recorded from serial sections. The software has primarily been used for studying shapes and dimension of brain regions (contour line data) and distributions of cellular elements such as neuronal cell bodies or axonal terminal fields labeled with tract-tracing techniques (point data). The tissue elements recorded could equally well be labeled with use of other techniques, the only requirement being that the data collected are saved as x,y,z coordinates. Data are typically imported from image-combining computerized microscopy systems or image analysis systems, such as Neurolucida (MicroBrightField, Colchester, VT) or analySIS (Soft Imaging System, GmbH, Münster, Germany). System requirements are a PC running LINUX. Reconstructions in Micro3D may be rotated and zoomed in real-time, and submitted to perspective viewing and stereoimaging. Surfaces are re-synthesized on the basis of stacks of contour lines. Clipping is used for defining section-independent subdivisions of the reconstruction. Flattening of curved sheets of points layers (e.g., neurons in a layer) facilitates inspection of complicated distribution patterns. Micro3D computes color-coded density maps. Opportunities for translation of data from different reconstructions into common coordinate systems are also provided. This article demonstrates the use of Micro3D for visualization of complex neuronal distribution patterns in somatosensory and auditory systems. The software is available for download on conditions posted at the NeSys home pages (http://www.nesys.uio.no/) and at The Rodent Brain Workbench (http://www.rbwb.org/).

Assumption 2: opaque to intuition?

AbstractAim The aim of this paper was to revise the historical biogeographical method for resolving complicated distribution patterns through a technique that has come to be called assumption 2. Assumption 2 was used to resolve multiple areas on a single terminal branch (masts) as well as paralogous and missing areas in two or more areagrams. Recent examples, however, have shown that assumption 2 may be using rather than resolving paralogy. The paper attempts to resolve this problem by formulating a separate procedure to avoid using paralogous (redundant) area data in area cladistic analyses.Method The revision results in a new derivative method, the transparent method, to replace assumptions 1 and 2. It separates the procedures for resolving paralogy and for solving distribution patterns that occur in more than one area (masts).Results Several hypothetical examples show how the transparent method reduces paralogy and masts. The results show that paralogy can be reduced if the paralogy subtree method is applied after uncovering all possible relationships as single components on the terminals of areagrams.Conclusion The transparent method is a significant step forward in cladistic biogeography as it utilizes area relationships rather than generating general areagrams based on paralogous data.

Nitrogen and carbon isotopic composition of high-molecular-weight dissolved organic matter in marine environments

High-molecular-weight (HMW) dissolved organic matter (DOM) was isolated using cross-flow ultrafiltration from seawater across a salinity gradient in 2 estuarine/coastal marine envi- ronments —Chesapeake Bay/Middle Atlantic Bight (MAB) and Galveston Bay/Gulf of Mexico. Nitrogen and carbon isotope ratios (δ 15 N and δ 13 C) were measured on the isolated HMW DOM sam- ples (defined here as the size fraction between 1 and 200 nm), which made up ~50 to 60% of the total DOM in the estuarine regions and decreased to ~35% of the DOM at the MAB and Gulf of Mexico stations. δ 15 N values varied from 4.8 to 8.1 ‰ in the Chesapeake Bay/MAB area. In the Galveston Bay/Gulf of Mexico region, δ 15 N and δ 13 C values varied from 3.2 to 9.5‰ and -26.1 to -20.9‰, respectively. Similar distribution patterns of δ 13 C and δ 15 N were observed in both study areas, with values of δ 15 N showing a mid-salinity maximum of about 8 to 10‰, whereas δ 13 C continually increased with increasing salinity. The δ 13 C values clearly demonstrated a shift of HMW organic car- bon sources from largely terrestrial inputs in the upper-estuarine areas to marine-dominated organic carbon sources in lower-estuarine and coastal regions. The more complicated distribution patterns of δ 15 N, with δ 15 N values first increasing with salinity in estuarine regions then decreasing towards the seawater endmember, suggest more dynamic N cycling. Thus, in addition to organic matter sources, biogeochemical and isotopic fractionation processes are important factors governing marine HMW DOM δ 15 N values. Vertical profiles of HMW DOM δ 13 C in open-ocean stations generally decrease from surface water to deep waters, whereas the opposite was found for δ 15 N. HMW DOM compo- nents with heavier δ 13 C and lighter δ 15 N values seem to be preferentially degraded during their trans- port from surface to deep waters. However, other processes could also have contributed to this distri- bution trend. While the carbon isotopic signature can be used as an indicator of DOM sources, nitrogen isotopic composition, on the other hand, appears to be related to both source functions and subsequent recycling in marine environments. Comparisons of δ 15 N with previously published ∆ 14 C values for the same samples support these conclusions about possible 15 N degradation pathways.

Sedimentary organic carbon and nitrogen contents and their isotopic compositions along two transects on the East China Sea shelf.

Surficial sediment samples were collected from two transects on the shelf of the East China Sea: one across the shelf and the other along the coast, both starting near the Changjiang river mouth. They were analyzed for contents of total nitrogen (TN%) and total organic carbon (TOC%) and for their isotopic compositions (δ15N and δ13CTOC). The TOC% and TN% values varied concomitantly in the ranges of 0.2 to 1.5% and 0.02 to 0.19%, respectively. The δ13CTOC value ranged from −25.1 to −19.6‰. The lower δ13CTOC values ( 0.5%). Away from the coastal zone, TOC% dropped sharply with corresponding increase in the δ13CTOC value. The δ15N value, varying from 3.6 to 4.9‰, displayed a more complicated distribution pattern. Distinctively lower δ15N values (<4.1‰) occurred near the Changjiang river mouth and near the shelf edge. Isotopically light riverine nitrogenous materials and preferential uptake of isotopically light nitrogen in the rich supply of nutrients in the Changjiang plume may have contributed to the observed low values near the river mouth, while nitrogen fixers in the Kuroshio waters may have contributed to those near the shelf break.

Preliminary Study of the Dynamic Origin of the Distribution Pattern of Bottom Sediments on the Continental Shelves of the Bohai Sea, Yellow Sea and East China Sea

The bottom sediment types in the Bohai Sea, Yellow Sea and East China Sea (BYECS) are diversified, and their distribution pattern is very complicated. However, the bottom sediment types can be simplified to be sandy sediment, clayey sediment and mixed sediment, which comprise the complicated distribution pattern of bottom sediment in the BYECS. The continental shelves of the BYECS are broad, with shallow water depths and tidal currents which are permanent and dominate the marine dynamics in the BYECS. Based on numerical simulation of tidal elevations and currents in the BYECS, the rates of suspended load transport and bed load transport during a single tidal cycle for sediments of eight different grain size ranges are calculated. The results show that any sediment, whose threshold velocity is less than that of tidal current, has the same transport trend. Suspended load transport rate, bed load transport rate, and the ratio of the former to the latter decrease with grain size becoming coarser and coarser. The erosion/accretion patterns of sediments with different grain sizes are determined by the sediment transport rate divergences, and the results show that the patterns are the same for sediments with different grain sizes. Three main bottom sediment types, i.e. sandy sediment mainly composed of fine sand, clayey sediment mainly composed of silty clay, and mixed sediment mainly composed of fine sand, silt, and clay, are obtained by computation. The three bottom sediment types and their distribution pattern are consistent not only with sediment transport field and the sea bed erosion/accretion pattern obtained by simulation, but also with field data of bottom sediment types and divisions. In the BYECS, sand ridges form mainly in the areas with strong rectilinear tidal currents, sand sheets form mainly in the areas dominated by strong rotatory tidal currents, and clayey sediments, i.e. mud patches, form mainly in the areas with weak tidal currents. Hence, not only the sandy sediments but also the clayey sediments in the BYECS are formed under the control of the whole tidal current field of the BYECS. The three main bottom sediment types are not isolated respectively—in fact, they constitute a whole tidal depositional system. Under the condition with no cyclonic cold eddy, the clayey sediments in the BYECS can form in weak tidal current environments. Therefore, a cold eddy is not necessary for the deposition of clayey sediments in the BYECS.

Analysis of Scattered Sound from Underwater Hollow Cylinders Using the Wigner Distribution Function

The scattered sound from an aluminum hollow cylinder in water is analyzed using the Wigner distribution function. When sound is scattered by a thick-shelled cylinder, the creeping wave appears after the specular-reflected wave. As the thickness of the cylinder shell decreases, however, the creeping wave tends to disappear and ridges parallel to the time axis come into the time-frequency plane because of the resonance in the cylinder. While the backscattered wave exhibits a complicated distribution pattern, the wave scattered at 90 degrees is relatively monotonic. From the computer simulation that the removal of the transverse wave propagating in the cylinder results in the emphasis of the specular reflection and the pattern becomes monotonic in the time-frequency plane, the presence of the transverse wave influences strongly the characteristics of the scattered sound from an elastic object. Since the distribution in the plane exhibits a characteristic pattern in every case, the Wigner distribution function offers an effective means to analyze the scattered sound from an object in water.

Statistical Fatigue Properties of Structural Steels Based on Materials Strength Database for Reliability Design(MSDRD).

A large-scale database MSDRD on mechanical properties of structural materials such as metals, composites and ceramics was constructed by The Research Group for Statistical Aspects of Materials Strength. In this study, fatigue data of carbon steels and alloy steels for machine structural use are obtained from the present database and distribution characteristics of fatigue properties are analyzed by a statistical procedure developed by the authors. It is found that fatigue lives of the respective steels have a complicated distribution pattern depending on the stress level and that mixed-mode Weibull distribution is preferable to represent the fatigue life distribution in a wide variety of steels and a wide range of stress levels. In fact, statistical fatigue properties thus analyzed are in good agreement with the experimental data filed in MSDRD and analytical results are applicable to the reliability design of mechanical structures.

Occurrence of Toxic Metabolites from Nonionic Surfactants in the Krka River Estuary

The occurrence and behavior of nonylphenol (NP), nonylphenol monoethoxylate (NP1EO), and nonylphenol diethoxylate (NP2EO) were studied in the Krka River estuary. Quantitative determinations using normal-phase high-performance liquid chromatography with spectrofluorimetric detection were performed in both municipal wastewaters and receiving estuarine waters. The concentrations of NP, NP1EO, and NP2EO in municipal wastewaters varied within the ranges of <0.5-419, <0.5-35, and <0.5-54 μg/liter, respectively; thus, in general representing only a minor fraction of the total surfactant-derived nonylphenolic compounds. The concentration decrease after the wastewater discharge into the estuary was very sharp, which was assigned primarily to an efficient dilution of the wastewater plume. Consequently, the concentrations of NP, NP1EO, and NP2EO in the estuary were fairly low, the respective concentration ranges being <20-1200, <20-440, and <20-1300 ng/liter. Rather complicated distribution patterns of NP, NP1EO, and NP2EO were obtained on the vertical profile of the estuarine,water column with the concentration maxima at the estuarine phase boundaries, i.e., air-freshwater and freshwater-seawater. Moreover, the ratio between individual nonylphenolic compounds varied significantly, indicating that transformation reactions played a significant role in their distribution and fate in the estuary.

Identification of Forest Cover Changes by Landsat MSS Data and Environmental Effects of Such Changes in Central South Sri Lanka.

Based on Landsat MSS data of 1977 and 1987 together with in situ surveys, landcover and landuse maps are made for the central southern part of Sri Lanka then the change of landcover and deforestation in 10 years period is estimated. The change amounts to 16 % decrease in evergreen forests, 39 % increase in scrublands and 63 % decrease in open water areas.Analyses of 30 yeras monthly and annual mean precipitation and air temperature data collected from the surrounding observing stations indicate a complicated distribution pattern with a fairly large variability in case of precipitation while in case of air temperature 5 years moving average of the annual air temperature indicates a steady increase. These facts well coincide with the villagers perception on the natural environments.

New records of bats (Chiroptera) from Turkey

Abstract As the bat fauna of Turkey is only poorly documented, extensive additional distribution data are given, especially for Tadarida teniotis, Plecotus auritus P. austriacus, Myotis nattereri, M. bechsteini, M. emarginatus, M. daubentoni, M. (mystacinus) przewalskii, Hypsugo savil and Nyctalus leisleri (cf. Fig. 1, 4–5). For these species the new records simplify the picture considerably as no complicated distribution pattern in the Near East needs to be assumed. For some species data on biometrics and biology are included.

Application of remotely sensed data to the detection of sea surface phenomena

Based on the remotely sensed data of airborne-MSS, Landsat-MSS, Landsat-RBV camera and meteorological satellite GMS, sea surface phenomena around Japan were investigated. As to detection of oil slicks and suspended substances, the shorter wave-length in the visible spectrum were recognized as in general effective through the year and the thermal IR data was not so effective in warm season comparing with cold season. For detection of expanding patterns of river effluent and oceanic front, the effectiveness of thermal IR data obtained by timelapse observation were also recognized as fair. It is found that the shorter wavelengths in the visible spectrum are fairly effective in detecting the distribution pattern of water masses in coastal area. The existence of fairly complicated distribution patterns of sea ice in the Sea of Okhotsk was revealed by meteorological staellite GMS data, Landsat-MSS and Landsat-RBV camera data, and Landsat-MSS and Landsat-RBV camera data were concluded as more effective than GMS data in the detection of the distribution pattern of sea ice.