High-resolution Plots Research Articles

Nonlinear Extension of the Dynamical Linear Response of Spin: Extended Heisenberg Model

We introduce a new extended Heisenberg model. The model contains the orbital-dependent spins together with the retarded effects of spin torque. The model is directly derived from the dynamical linear response functions on the transversal spin fluctuation. Our model allows us to address effects which are not accessible via the usual Heisenberg model. With the model, we can describe not only the relaxation effects due to the Landau damping caused by the Stoner excitations, but also the nesting effects of the Fermi surface. We discuss possibilities of the extended Heisenberg model based on the high-resolution plots of the spin susceptibility for Fe.

Shale Reservoir Drainage Visualized for a Wolfcamp Well (Midland Basin, West Texas, USA)

Closed-form solution-methods were applied to visualize the flow near hydraulic fractures at high resolution. The results reveal that most fluid moves into the tips of the fractures. Stranded oil may occur between the fractures in stagnant flow zones (dead zones), which remain outside the drainage reach of the hydraulic main fractures, over the economic life of the typical well (30–40 years). Highly conductive micro-cracks would further improve recovery factors. The visualization of flow near hypothetical micro-cracks normal to the main fractures in a Wolfcamp well shows such micro-cracks support the recovery of hydrocarbons from deeper in the matrix, but still leave matrix portions un-drained with the concurrent fracture spacing of 60 ft (~18 m). Our study also suggests that the traditional way of studying reservoir depletion by mainly looking at pressure plots should, for hydraulically fractured shale reservoirs, be complemented with high resolution plots of the drainage pattern based on time integration of the velocity field.

High-resolution geochemical records of deposition couplets in a palaeolandslide-dammed reservoir on the Chinese Loess Plateau and its implication for rainstorm erosion

The sediment sequences retained by landslides and check dams on the Chinese Loess Plateau (CLP) are ideal for tracing historical catchment erosion, hydrological events and land use. This study explored a geochemical proxy to plot visible and non-visible deposition couplets in a sediment sequence from the CLP, in order to better trace soil erosion associated with historical rainstorms. An intact sediment sequence core (JB-2) was acquired in a palaeolandslide-dammed reservoir in Jingbian County, Shaanxi Province. The high-resolution elemental distribution of the entire core was generated by an Anaatech XRF Core Scanner. The water content and grain size were analysed in discrete samples of the representative core section. The Rb/Zr ratio was recommended as a high-resolution geochemical proxy for plotting the deposition couplets. Annual freeze–thaw layers among the couplets were then identified by the correlation between the Ca/Zr and Fe/Zr ratios. As a result, 41 deposition couplets and 18 annual freeze–thaw layers were identified in the JB-2 sediment sequence, indicating that 41 rainstorms occurred over 18 years during the survival of the reservoir. Furthermore, the ranges of couplet and annual specific sediment yields were 0.06–3.09 × 104 t km−2 and 0.06–3.42 × 104 t km−2 year−1 in the JB-2 reservoir, respectively. High annual specific sediment yields were the combined consequence of high annual rainfall frequency and the sediment yields associated with the rainstorm intensities. This study highlights the use of high-resolution plots of deposition couplets for providing a basis for the reconstruction of recent and contemporary soil erosion records and for determining the implication of past rainstorm intensities and frequencies on the CLP.

New Chaotic Dynamical System with a Conic-Shaped Equilibrium Located on the Plane Structure

This paper presents a new autonomous deterministic dynamical system with equilibrium degenerated into a plane-oriented hyperbolic geometrical structure. It is demonstrated via numerical analysis and laboratory experiments that the discovered system has both a structurally stable strange attractor and experimentally measurable chaotic behavior. It is shown that the evolution of complex dynamics can be associated with a single parameter of a mathematical model and, due to one-to-one correspondence, to a single circuit parameter. Two-dimensional high resolution plots of the largest Lyapunov exponent and basins of attraction expressed in terms of final state energy are calculated and put into the context of the discovered third-order mathematical model and real chaotic oscillator. Both voltage- and current-mode analog chaotic oscillators are presented and verified by visualization of the typical chaotic attractor in a different fashion.

Landscape controls and vertical variability of soil organic carbon storage in permafrost-affected soils of the Lena River Delta

To project the future development of the soil organic carbon (SOC) storage in permafrost environments, the spatial and vertical distribution of key soil properties and their landscape controls needs to be understood. This article reports findings from the Arctic Lena River Delta where we sampled 50 soil pedons. These were classified according to the U.S.D.A. Soil Taxonomy and fall mostly into the Gelisol soil order used for permafrost-affected soils. Soil profiles have been sampled for the active layer (mean depth 58±10cm) and the upper permafrost to one meter depth. We analyze SOC stocks and key soil properties, i.e. C%, N%, C/N, bulk density, visible ice and water content. These are compared for different landscape groupings of pedons according to geomorphology, soil and land cover and for different vertical depth increments. High vertical resolution plots are used to understand soil development. These show that SOC storage can be highly variable with depth. We recommend the treatment of permafrost-affected soils according to subdivisions into: the surface organic layer, mineral subsoil in the active layer, organic enriched cryoturbated or buried horizons and the mineral subsoil in the permafrost. The major geomorphological units of a subregion of the Lena River Delta were mapped with a land form classification using a data-fusion approach of optical satellite imagery and digital elevation data to upscale SOC storage. Landscape mean SOC storage is estimated to 19.2±2.0kgCm−2. Our results show that the geomorphological setting explains more soil variability than soil taxonomy classes or vegetation cover. The soils from the oldest, Pleistocene aged, unit of the delta store the highest amount of SOCperm2 followed by the Holocene river terrace. The Pleistocene terrace affected by thermal-degradation, the recent floodplain and bare alluvial sediments store considerably less SOC in descending order.

Stable isotopes in fish eye lenses as potential recorders of trophic and geographic history.

We evaluated eye lenses as potential recorders of stable isotope histories in fish because they consist of metabolically inert optical proteins that are deposited in successive, concentric circles (laminae) much like otolith circuli and tree rings. We conducted four different tests on lenses from red snapper, red grouper, gag, and white grunt. The first test was a low-resolution screening of multiple individuals (4–5 radial groups of laminae per lens, all species except white grunt). Along the radial axis, all individuals exhibited substantial isotopic variability. Red snapper individuals separated into two groups based on δ 15N and gag separated into two groups based on δ 13C. Two gag with the greatest variation were chosen for high-resolution temporal analysis using individual laminae from their second eye lenses. The first-order patterns from the high-resolution analysis generally mimicked patterns from the low-resolution screening of grouped laminae, yet the high-resolution plots revealed early-life details that were not apparent in the low-resolution screenings. For the third test, left- versus right-eye variation was compared using high-resolution methods. White grunt left- and right-eye radial isotopic patterns were almost identical for both δ 13C and δ 15N, suggesting the variations observed among individual fish were not artifacts. The final test evaluated intra-laminar variation; multiple samples were analyzed from different parts of the same lamina. Seven laminae from three individuals of two species were analyzed in this manner; variations among laminae were found to be much higher than variations within laminae. However, nominal intra-laminar variations were comparable to nominal differences between left and right lenses, suggesting intra-laminar variation established measurement precision. Eye lens isotopes appear to be useful for reconstructing the isotopic histories of individual fish; these histories can be compared with spatially-derived isoscapes to reconstruct individual histories for site fidelity, movement and trophic position.

The influence of model grid resolution on estimation of national scale nitrogen deposition and exceedance of critical loads

Abstract. The Fine Resolution Atmospheric Multi-pollutant Exchange model (FRAME) was applied to model the spatial distribution of reactive nitrogen deposition and air concentration over the United Kingdom at a 1 km spatial resolution. The modelled deposition and concentration data were gridded at resolutions of 1 km, 5 km and 50 km to test the sensitivity of calculations of the exceedance of critical loads for nitrogen deposition to the deposition data resolution. The modelled concentrations of NO2 were validated by comparison with measurements from the rural sites in the national monitoring network and were found to achieve better agreement with the high resolution 1 km data. High resolution plots were found to represent a more physically realistic distribution of reactive nitrogen air concentrations and deposition resulting from use of 1 km resolution precipitation and emissions data as compared to 5 km resolution data. Summary statistics for national scale exceedance of the critical load for nitrogen deposition were not highly sensitive to the grid resolution of the deposition data but did show greater area exceedance with coarser grid resolution due to spatial averaging of high nitrogen deposition hot spots. Local scale deposition at individual Sites of Special Scientific Interest and high precipitation upland sites was sensitive to choice of grid resolution of deposition data. Use of high resolution data tended to generate lower deposition values in sink areas for nitrogen dry deposition (Sites of Scientific Interest) and higher values in high precipitation upland areas. In areas with generally low exceedance (Scotland) and for certain vegetation types (montane), the exceedance statistics were more sensitive to model data resolution.

Differentiation of Staphylococcus spp. by high-resolution melting analysis

High-resolution melting analysis (HRMA) is a fast (post-PCR) high-throughput method to scan for sequence variations in a target gene. The aim of this study was to test the potential of HRMA to distinguish particular bacterial species of the Staphylococcus genus even when using a broad-range PCR within the 16S rRNA gene where sequence differences are minimal. Genomic DNA samples isolated from 12 reference staphylococcal strains (Staphylococcus aureus, Staphylococcus capitis, Staphylococcus caprae, Staphylococcus epidermidis, Staphylococcus haemolyticus, Staphylococcus hominis, Staphylococcus intermedius, Staphylococcus saprophyticus, Staphylococcus sciuri, Staphylococcus simulans, Staphylococcus warneri, and Staphylococcus xylosus) were subjected to a real-time PCR amplification of the 16S rRNA gene in the presence of fluorescent dye EvaGreen™, followed by HRMA. Melting profiles were used as molecular fingerprints for bacterial species differentiation. HRMA of S. saprophyticus and S. xylosus resulted in undistinguishable profiles because of their identical sequences in the analyzed 16S rRNA region. The remaining reference strains were fully differentiated either directly or via high-resolution plots obtained by heteroduplex formation between coamplified PCR products of the tested staphylococcal strain and phylogenetically unrelated strain.

Metabolic profiling of Rhodiola rosea rhizomes by 1H NMR spectroscopy

Rhodiola rosea is a broadly used medicinal plant with largely unexplored natural variability in secondary metabolite levels. The aim of this work was to develop a non-target procedure for ¹H NMR spectroscopic fingerprinting of rhizome extracts for pattern recognition analysis and identification of secondary metabolites responsible for differences in sample composition. To achieve this, plants from three different geographic areas (Swiss Alps, Finland, and Altai region in Siberia) were investigated. A sample preparation procedure was developed in order to remove polymeric polyphenols as the ¹H NMR analysis of low-molecular-weight metabolites was hampered by the presence of tannins. Principal component analysis disclosed tight clustering of samples according to population. PCA models based on the aromatic region of the spectra showed that the first two components reflected changes in the content of salidroside and rosavin, respectively, the rosavin content being negatively correlated to that of rhodiocyanoside A and minor aromatics. Score plots and non-parametric variance tests demonstrated population-dependent changes according to harvest time. Data consistency was assessed using score plots and box-and-whisker graphs. In addition, a procedure for presenting loadings of PCA models based on bucketed data as high-resolution plots, which are reminiscent of real ¹H NMR spectra and help to identify latent biomarkers, is presented. This study demonstrated the usefulness of the established procedure for multivariate non-target ¹H NMR metabolic profiling of Rhodiola rosea.

Shadow bands observed during the total solar eclipse of 4 December 2002, by high-resolution imaging

This paper presents results of a comparison between the characteristics of shadow bands recorded during the total solar eclipse of 4 December 2002 in Botswana, and the theory of Codona (Codona, 1986, Astronomy and Astrophysics 164, 415–427). For the first time the analysis was based on images of the phenomenon and not photometric data. Thanks to this, use was made of high spatial resolution and detailed plots of power spectra were obtained. The plots’ shapes are in excellent agreement with those predicted by theory. From them, the height of the scattering layer producing shadow bands was inferred.

Anisotropies in the redshift-space correlations of galaxy groups and clusters -- II. Analysis of observational cluster samples

We study the redshift-space correlation function of galaxy clusters for observational samples constructed in different surveys. We explore correlation amplitudes, pairwise velocity distributions and bias factors. Systematic effects in cluster identification procedures are the main source of biased estimates of the correlation amplitude and inferred velocity dispersions. We find that the large elongations along the line of sight in the Abell catalogue cannot be explained solely in terms of the errors in distance measurement originating from using a small number of galaxies. The inclusion of a significant fraction of galaxies and systems not physically bound to the clusters is responsible for this large systematic effect. We also find a significant dependence of the redshift-space distortion of the correlation function on the cluster Bautz-Morgan (BM) type, an effect that may rely on the fact that, owing to the regular appearance of low Bautz-Morgan type clusters, a sample of such objects would be less contaminated. We confirm that the effect of a low number of redshift measurements, n z , is to increase the redshift-space correlation length and bias factor. The results are very stable for n z > 10. We also test the effects of different n z in the catalogue of groups/clusters derived from the Updated Zwicky Catalogue and find that, for cluster samples identified in redshift surveys, even a low number of redshifts n z ∼ 5 is sufficient to provide reliable results. By comparing our results with those of numerical simulations we explore the strong influence on the clustering distortion pattern in redshift space from effects associated with the cluster identification procedure from two-dimensional surveys. The identification of clusters in X-ray surveys improves this situation, although there are still systematic effects, which are probably due to identification of optical sources in the determination of cluster redshifts. These systematic effects are particularly strong for the most luminous X-ray-selected clusters in the Extended Bright Cluster Survey, which exhibits very large anisotropies, comparable to those present in the Abell catalogue. Our results demonstrate that forthcoming large redshift surveys will be extremely important for the construction of new samples of groups and clusters, as well as improving the determination of optical and X-ray-selected cluster distances, essential for reliable analyses of the large-scale structure. High-resolution plots and information are available at http://star-www.dur.ac.uk/∼nelsonp/ anisotropies.

Anisotropies in the redshift-space correlations of galaxy groups and clusters -- I. Simulated catalogues

We analyse the correlation function of mock galaxy clusters in redshift space. We have constructed several mock catalogues designed to mimic the selection biases inherent in a variety of observational surveys. We explore different effects that contribute to the distortion of the clustering pattern: the pairwise velocity distribution of galaxy systems, coherent bulk motions, redshift errors and systematic effects in cluster identification. Our tests show that the redshift-space clustering pattern of galaxy systems is highly influenced by effects associated with the identification procedure from two-dimensional surveys. These systems show a spuriously large correlation amplitude, an effect that is present and even stronger in a subsample where the angular positions coincide with three-dimensional identified clusters. The effect of a small number of redshift measurements is also that of increasing the correlation amplitude. In a similar fashion, the bias parameter inferred from cluster samples is subject to these observational problems, which induce variations of up to a factor of 2 in such determinations. Also, we find that the estimated mean pairwise velocity dispersion can be up to an order of magnitude larger than the actual value. Errors in the estimated cluster redshift, originating from the use of too few redshift measurements per cluster, have a smaller impact on the measured correlation function. We show that an angular incompleteness in redshift surveys, such as that present in the 2dF Galaxy Redshift Survey 100 k public release, has no significant effect on the results. We suggest that the nature of projection effects arises mainly from structures along the line of sight in the filamentary large-scale clustering pattern. Thus, spectroscopic surveys are the only means of providing unbiased cluster samples. High-resolution plots and information are available at http://star-www.dur.ac.uk/~nelsonp/anisotropies.

Multiple Car-Following Data with Real-Time Kinematic Global Positioning System

The real-time kinematic differential Global Positioning System (GPS) has facilitated a new horizon in traffic engineering. Multiple car-following experiments conducted with a real-time kinematic GPS with 10 vehicles participating in a probing field gave high-quality results in headway, speed, relative speed, and acceleration. The expected accuracies for measuring position and speed were 10 mm and 0.16 km/h, respectively. The vehicles were driven in a loop consisting of two parallel straight sections connected by two semicircular curves. Different driving conditions were induced in the platoon by instructing the leading driver to follow predetermined speed variations. The experiments yielded sets of continuous observations. Headway, speed, and acceleration were measured using conventional equipment for the purpose of comparing accuracy. The accuracy of the data obtained using the GPS was superior to that of the same data obtained using conventional measurements. The variation in driving characteristics down the stream of vehicles was studied using the experimental data. The results showed that the reaction time between a change in relative speed and the corresponding change in acceleration varies during the driving process. The reaction time of individual drivers also changes along the platoon. The good-quality data were able to give high-resolution plots of acceleration and relative speed illustrating that both the reaction time and the functional relationship between acceleration and relative speed do not remain constant.

Adsorption and thermogravimetric methods for monitoring surface and structural changes in ordered mesoporous silicas induced by their chemical modification

The current work demonstrates that the standard adsorption analysis has a limited applicability for characterization of chemically modified porous silicas. Since low-pressure nitrogen adsorption isotherms are sensitive to the surface changes caused by chemical modification of silicas, these isotherms were successfully used to evaluate their surface heterogeneity during different stages of modification. The surface analysis was accomplished by using adsorption energy distributions and high-resolution comparative plots.

Multiple-source localization using GPS technology and received arrival time structure analysis in an air-deployed system

An efficient and robust method has been developed to locate multiple impulsive sources in an ocean environment. Global position system (GPS) receivers were installed on sonobuoys to obtain their locations within a few meters of accuracy. A sonobuoy field was deployed in a ring-type pattern. Charges were then set off at arbitrary locations within the ring, High-resolution plots were used to obtain direct path and/or first bottom bounce arrivals on each buoy. A model grid of arrival times was constructed, corresponding to the dimensions of the buoy field. A ray model previously developed here at the Applied Research Laboratories at the University of Texas at Austin (ARL:UT) was used to obtain model travel times. The minimum value of the least-square-type error between the real arrival times and the modeled travel times resulted in an unambiguous location of the source, within the limits of the grid spacing chosen. This value was calculated by picking one receiver as the reference and then summing the timing errors of the remaining receivers relative to the reference. Successive iterations with finer grid spacings result in source localization within the accuracy of the buoy locations. The localization routine was extended by allowing permutations of the pulse arrivals on each buoy to account for multiple sources closely separated in time and/or space. An automated correlation technique is presented as an alternative to the leading edge-detection method used here for obtaining relative arrival times. Two proof-of-concept experiments were performed and some results of data obtained at Lake Travis and the Gulf of Mexico are presented.

Source localization via received arrival time structure analysis

An efficient and robust method has been developed to locate impulsive sources in an ocean environment. A sonobuoy field was first deployed in a ring-type pattern. GPS receivers were installed on the buoys to obtain their locations within a few meters of accuracy. Charges were then set off at arbitrary locations within the ring. High-resolution plots were used to obtain direct path and first bottom bounce arrivals on each buoy. A model grid of arrival times was constructed, corresponding to the dimensions of the buoy field. A ray model previously developed here at ARL:UT [E. K. Westwood and P. J. Vidmar, J. Acoust. Soc. Am. 81, 912–924 (1987)] was used to obtain model travel times. The minimum value of the least-square error between the real arrival times and the modeled travel times resulted in an unambiguous location of the source, within the limits of the grid spacing chosen. This value was calculated by picking one phone as the reference and then summing the errors of each phone relative to the reference. Successive iterations with finer grid spacings results in source location within the accuracy of the buoy locations. Results obtained at Lake Travis and the Gulf of Mexico will be presented. [This work is supported by Navy Strategic Systems Programs.]

Simple microcomputer system for mapping tissue sections with the light microscope

We describe a method for two-dimensional mapping of tissue sections that makes use of a drawing tube, microscope stage encoders and a microcomputer. The drawing tube views the graphics monitor and superimposes the image of the screen cursor and on-screen menus on the specimen image. Thus, the position of every landmark in each microscopic field can be mapped without stage movement while directly viewing the specimen through the microscope. A mouse is used for data entry and program control. Fields mapped in this way are then assembled into a complete map, which can include line drawings as well as up to 20 landmark types. The coordinate values of all landmarks mapped are stored and remain accessible for editing and analysis. High resolution plots are produced. Specialized functions include grain counting, area and perimeter calculations as well as a perimeter limiter that predefines the area to be mapped. The system uses general purpose hardware that is widely available. Many hitherto time-consuming tasks, such as detailed mapping of cell positions, regions of immunocytochemical staining, degenerating fibers, neuronal connections or any other anatomical feature, can be done in a fraction of the time and effort previously involved. These labor savings can be realized while maintaining the highest resolution and enabling statistical analysis since the data are already in digital form.

An integrated automatic measuring system for internal ballistics testing

Summary form only given, as follows. An integrated measurement system is described that can make fast (100-MHz) multichannel real-time digitized measurements, process the data, and file results data in a computer disc storage system. High-level commands enable automated sequences to be set up with autocalibration and scaling of the data. The data can be reviewed and edited prior to storage so that only useful portions are filed. High-resolution screen graphics and full color plots of the data are available immediately. The result is that scientific measurements that previously required high-speed oscilloscopes or instrumentation recorders, and then painstaking data analysis, can now be performed on local workstations, with data preprocessed for mainframe archiving. With this integrated system, ballistics tests that normally take two weeks are now reduced to a few minutes. >

On-line analysis of rapid motion with a microcomputer

A software package is described, which uses an Apple IIe computer with a digitizing board (Digisector 65) for analysing rapid motions of appendages of small insects from video images. Every 20 ms the program simultaneously analyses (1) the position of two moving appendages after a background correction and (2) the externally applied trigger stimulus. The data may be plotted in high-resolution plots with a matrix printer and evaluated with statistical methods.

High-Resolution Plots of Trigonometric Functions

At an early level, most students become familiar with the traditional twodimensional plots using X-Y rectangular coordinates. Given a series of data points in the X-Y plane, these same students should normally have little difficulty displaying their data given the appropriate scales with which to work. The more adventuresome computer buffs will probably delight in generating various BASIC plot routines on a microcomputer.