Block Borders Research Articles

過去200万年間における宮崎平野の地層形成と陸化プロセス

The Miyazaki Plain is situated at the western end of the forearc of the Southwest Japan Arc, and is one of the standard areas of the Quaternary system in Japan. Many tephra layers were supplied from volcanoes in the Ryukyu and Southwest Japan arcs during Quaternary. The authors establish the stratigraphy and chronology of sediments during middle Pleistocene to Holocene in the Miyazaki Plain using tephrochronological methods, and discuss landform development and tectonics. The sediments are subdivided into Kariya formation, Nojiri formation (the Highest terraces), the Higher terrace deposits, the Middle terraces deposits, the Lower terraces deposits, and the Holocene formation (alluvium plain). Kariya formation of 1 Ma-500 ka, is fluvial sediments which are partially accompanied by marine sediments. Nojiri formation is 500-300 ka old and fluvial and marine sediments form the highest terraces. Shiinoki member in Nojiri formation has a transgressive sediment and is correlated with MIS 9. The higher terraces are composed of Kukino fluvial terrace of 330-240 ka and Chausubaru fluvial terrace of 240 ka. The middle terraces consist of the four fluvial and marine terraces: Sanzaibaru terrace of 140-120 ka, Baba terrace of 110 ka, Nyutabaru terrace of 110-90 ka, Karasebaru terrace of 90 ka, and Saitobaru terrace of 90-80 ka. Sanzaibaru terrace with a thick transgressive sediment and well-developed marine terraces correlates with MIS 6-5e. Nyutabaru terrace is mainly fluvial accompanied partially by marine terraces, and emerged in MIS 5c. Baba and Saitobaru terraces are fluvial only. Saitobaru terrace with a gravel bed over 10-m thick indirectly corresponded to the transgression in MIS 5a. All of the lower terraces of 70-10 ka are fluvial, and are subdivided into ten terraces: Shimizu, Okatomi, Toyobaru 1, Toyobaru 2, Ikazuno, Oyodo, Fukadoshi 1, Fukadoshi 2, Mikazukibaru 1, and Mikazukibaru 2. Their steep longitudinal profiles indicate that sea-level when the terraces formed was lower than the recent one. This lower sea-level stage chronologically corresponds to MIS 4-2. Fukadoshi 1,2 terraces, the profile of which is the steepest of all the terraces, were formed in MIS 2, the last glacial maximum. Shimotajima marine terraces and recent alluvium correspond to Holocene high sea level and transgression in MIS 1. The tectonics of the Miyazaki Plain during the past 2 Ma are estimated from landforms and geological structures. During 2-1 Ma, the forearc basin beneath the sea was uplifted slowly and the Miyazaki Plain emerged. Then the left-lateral movement of Wanitsuka Mts block bordering the plain on the north formed the two pull-apart basins of the Kariya and Nojiri formations at the southern part of the plain during 1-0.3 Ma. The left-lateral movement was caused by the opening of the Okinawa Trough in the back arc of Ryukyu Arc. At 0.3 Ma, the Miyazaki plain suddenly began uplifting rapidly due to E-W trend compression. During 0.8-0.6 Ma, the movement direction of the Philippine Sea Plate changed from NW to WNW, and then the plate subducted obliquely along the Nankai trough. Consequently, the Southwest Japan forearc including the Miyazaki Plain decoupled from the inner arc, moving westward, and finally caused the E-W trend compression and uplifting around the Miyazaki Plain. The uplift rate of the southern part of the plain accelerated from 0.1 m/ka to 1 m/ka during the last 0.3 Ma at the southern part of the plain. In detail, the tectonical mode is domical uplifting the center, which is several kilometers off Miyazaki City in the Pacific Ocean. The domical uplifting and the increasing uplift rate relate to the isostasy of the subducting Kyushu-Palau Ridge on the Philippine Sea plate under the Miyazaki Plain or a rising serpentinite diapir in the crust of the Eurasia plate.

Agroforestry Adoption, Innovations and Smallholder Farmers' Motivations in Tropical Uplands of Southern Philippines

ABSTRACT A combination of Participatory Rural Appraisal (PRA) and household survey was conducted to understand what motivates Claveria farmers to plant trees and adopt agroforestry. Of the 300 households surveyed, 72% adopted agroforestry systems. Parkland system is the most widely practiced (30%), followed by hedgerow system or natural vegetative strips (NVS) (18%), block planting (16%), and border planting (8%). The agroforestry system adopted by farmers varies with their motivations. If the primary motive is to have additional income, farmers practice either block planting, border planting, or parkland system. For soil conservation, farmers prefer hedgerows system or NVS. Farmers wanting to protect their crops from strong winds plant trees along farm boundaries as windbreaks (border planting).

The Effect of Single-Nucleotide Polymorphism Marker Selection on Patterns of Haplotype Blocks and Haplotype Frequency Estimates

The definition of haplotype blocks of single-nucleotide polymorphisms (SNPs) has been proposed so that the haplotypes can be used as markers in association studies and to efficiently describe human genetic variation. The International Haplotype Map (HapMap) project to construct a comprehensive catalog of haplotypic variation in humans is underway. However, a number of factors have already been shown to influence the definition of blocks, including the population studied and the sample SNP density. Here, we examine the effect that marker selection has on the definition of blocks and the pattern of haplotypes by using comparable but complementary SNP sets and a number of block definition methods in various genomic regions and populations that were provided by the Encyclopedia of DNA Elements (ENCODE) project. We find that the chosen SNP set has a profound effect on the block-covered sequence and block borders, even at high marker densities. Our results question the very concept of discrete haplotype blocks and the possibility of generalizing block findings from the HapMap project. We comparatively apply the block-free tagging-SNP approach and discuss both the haplotype approach and the tagging-SNP approach as means to efficiently catalog genetic variation.

Simulation of Detachment of Porous Filter Cakes in Surface Filtration

The simulation for the detachment of filter cakes from filter media uses a dimension‐reduced model, in which the filter cake is divided into horizontal blocks. For each block the agent forces are balanced in order to ascertain detachment behavior. The simulation accounts for frictional forces at the block borders, interparticulate frictional and adhesive forces in the filter cake and adhesive forces between filter cake and filter medium. Through the simulation a pre‐optimization takes place, which has to be verified through experiment.

Minimum Description Length Block Finder, a Method to Identify Haplotype Blocks and to Compare the Strength of Block Boundaries

We describe a new probabilistic method for finding haplotype blocks that is based on the use of the minimum description length (MDL) principle. We give a rigorous definition of the quality of a segmentation of a genomic region into blocks and describe a dynamic programming algorithm for finding the optimal segmentation with respect to this measure. We also describe a method for finding the probability of a block boundary for each pair of adjacent markers: this gives a tool for evaluating the significance of each block boundary. We have applied the method to the published data of Daly and colleagues. The results expose some problems that exist in the current methods for the evaluation of the significance of predicted block boundaries. Our method, MDL block finder, can be used to compare block borders in different sample sets, and we demonstrate this by applying the MDL-based method to define the block structure in chromosomes from population isolates.

An incompleteLU-factorization algorithm based on block bordering

This paper suggests a new algorithm, called IBBLU, for constructing incomplete LU-factorizations of general non-singular sparse matrices. This algorithm is based on the block bordering idea and uses factorized sparse approximate inverses to approximate the inverses of pivot blocks. The triangular factors L and U are represented in explicit-implicit block form, which enhances the flop performance of the preconditioning. The algorithm suggested is theoretically justified for M- and H-matrices, and its competitiveness with the best available algebraic preconditioning methods in both symmetric and unsymmetric cases is demonstrated numerically. Copyright © 2000 John Wiley & Sons, Ltd.

Three-dimensional solution of mining-geometric problems in a graphic dialog regime in planning opencasts

In order to solve a complex of mining-geometric problems in a three-dimensional statement, triangulation models of the interfaces are used that differ from known models by excluding the requirement of uniformity for the support network and the application of structure-forming elements of deposits: planes of tectonic disturbances, borders of geological blocks, etc. The problem is formulated for evaluating the locations of opencast fields within their finite boundaries, and also in the dynamics of working. Algorithms are given for fulfilling the basic graphical and analytical operations in three-dimensional space, including dialog operations. Traditional parameters for analyzing mining operation regime are supplemented by new ones, i.e., physically required work for moving rock mass by means of transport and rehandling of overburden by draglines, and these parameters are determined for each stage of mining.

Application of apatite (U-Th)/He thermochronometry to the determination of the sense and amount of vertical fault displacement at the Chuquicamata porphyry copper deposit, Chile

Chuquicamata is the world's largest porphyry copper deposit, notwithstanding the fact that a portion of the orebody has been faulted off by postmineralization movement along the West fault. In order to locate the missing portion of the orebody in the vertical dimension, a study was designed to estimate the sense and amount of vertical displacement along this major structure by measuring the (U-Th)/He and fission-track ages of vertically distributed apatite samples from each of the crustal blocks (Fortuna and Chuquicamata Intrusive Complexes) bordering the fault. Apatite (U-Th)/He ages range from 32 to 16 Ma, whereas apatite fission-track ages range from 33 to 28 Ma, reflecting the lower closure temperature of the (U-Th)/He thermochronology method ( approximately 75 degrees vs. approximately 125 degrees C for cooling rates of approximately 10 degrees C/m.y.). The (U-Th)/He ages decrease systematically with depth in both blocks, however, the age-elevation curve for the western Fortuna block is shifted vertically with respect to the eastern Chuquicamata block, indicating that the postmineralization denudation was significantly greater to the west. The minimum vertical displacement along the West fault is estimated to be 600 + or - 100 m, implying that the missing portion of the Chuquicamata deposit should be located at a present-day elevation of at least 3,600 m. The new apatite ages, combined with previous thermochronometric data (Rb-Sr, U-Pb, Ar-Ar), reveal rapid cooling rates ( approximately 100 degrees C/m.y.) for the Chuquicamata deposit following emplacement at about 35 Ma, thereby indicating that the Cu mineralization took place at a depth of less than 4 km.

Hypothesis: for the worst and for the best, L1Hs retrotransposons actively participate in the evolution of the human centromeric alphoid sequences.

A number of questions concerning the evolution and the function of the alpha satellite DNA sequences present at the centromere of all human chromosomes are still open. In this paper, we present data which could contribute to understanding these points. It is shown here that the alphoid sequences within which L1 elements are found are quite divergent from those of the homogeneous alphoid subsets present at each centromere where none has so far been detected. In addition, a number of L1s are detected close to the ends of the alpha satellite blocks. A fairly high proportion exhibit a polymorphism of presence/absence. Strikingly, several L1s localized at a distance from each other are always either present or absent simultaneously. This is interpreted as resulting from intrachromosomal recombination, through distant L1s, leading to deletion of several of them at once together with their surrounding alphoid sequences. The parameters determining which portion of the several megabases of alphoid sequences is actually involved in the centromeric function are not known. From the above data we suggest that the alpha satellite domain within which DNA sequences are recruited to form a centromere is both homogeneous in sequence and uninterrupted by L1s or any other retrotransposons. Conversely, non-centromere competent alphoid sequences would be both divergent and punctuated by scattered L1 elements, particularly at the borders of the alphoid blocks. On the grounds of these data and hypotheses, a model is presented in which it is postulated that accumulation of L1 insertions within a centromere competent alphoid domain is ruining this competence, the consequence being damage to or even loss of the centromere-forming capability of the chromosome. Restoration of fully centromere-forming competence is supposed to occur by two alternative means, either de-novo amplification of a homogeneous and uninterrupted alphoid domain or by unequal crossing over with a homologue harbouring a large competent one. If L1 retrotransposons are acting detrimentally to centromere integrity (for the worst), one must also consider them as having positive consequences on chromosomes by preventing their centromeres from swelling indefinitely by the addition of alphoid sequences (for the best). The data and ideas presented here fit well with those already put forward by Csink and Henikoff (1998) using the example of Drosophila.

Principal characteristics of the Upper Silesian Block and Małopolska Block border zone (southern Poland)

The Upper Silesian and Małopolska blocks are situated near the southwestern boundary of the East European Platform within the Trans-European Suture Zone. The Lower Palaeozoic lithologies of the blocks reveal different stratigraphic and diastrophic development. In the Upper Silesian Block, unmetamorphosed and gently folded Lower Cambrian to Ordovician sedimentary rocks rest on a Cadomian basement. The Lower Cambrian is represented by an older (sub-Holmia) Borzęta Formation and a younger (Holmia) Goczałkowice Formation. The thickness of the Cambrian lithologies increases from the southwest towards the lateral part of the block. In the Małopolska Block Palaeozoic and Precambrian lithologies are represented by regionally metamorphosed and intensely folded Lower Cambrian–Vendian clastic rocks which are unconformably overlain by Ordovician–Lower Silurian carbonates and Upper Silurian clastic rocks. The crystalline basement of the Małopolska Block has yet to be recognized. The Lower Palaeozoic sediments of both blocks are overlain by Devonian and Carboniferous rocks. The blocks are in direct contact along a narrow tectonic zone, a part of the largely concealed Hamburg–Kraków fault zone, in which tectonic evolution has taken place spasmodically with strike-slip movements predominating.

Nonlinear adaptive processing of block coded images

An adaptive nonlinear scheme for the blocking effect reduction in low bit rate block coded images is presented. A method is developed to extract useful features from the compressed image and uses them as inputs to three-layer feedforward neural networks. The neural networks learn to reduce the coding errors in the block border areas. The new technique has been applied to process JPEG compressed images and results are presented which show improvements in both visual quality and peak-signal to noise ratio (PSNR).

Block position dithering in DCT-coded sequences

Abstract An attempt has been made to hide the false edges perceived at block borders in DCT-coded image sequences. The standard H.261 codec is extended by simple pre- and postprocessing: shifting the input image over small pseudo-random horizontal and vertical distances and shifting back the output image by the same amount. A subjective comparison by a panel of 20 observers has established a quality improvement for interframe coding, if both the current image and the previous image are subjected to the same shift. Masking the block borders by adding a time-invariant noise image to the output is found to be a desirable option.

Geoelectric signals in China and the earthquake generation process

We present original apparent resistivity records for stations located in the Chinese provinces of Hebei and Sichuan, along with seismicity patterns, fault maps, and limited hydrologic data. These records are part of a 30‐year database of geoelectric signals that have been recorded in China by a nationwide network of more than 100 stations set up by the State Seismological Bureau of the People's Republic of China. The database includes the time period during which the M 7.8 1976 Tangshan and M 7.2 1976 Songpan earthquakes occurred. Resistivity data recorded in and around the epicentral region of the Tangshan event show coherent changes, both temporal and in areal distribution, years and months before and after the earthquakes. A regional change in water table occurred more than 3 years prior to the Tangshan earthquake. The resistivity and water table signals appear to correlate in the 2‐ to 3‐year period prior to the earthquake. Rainfall records from the region around Tangshan, extending to the cities of Beijing and Tianjin, do not appear to account for the resistivity changes. Regional seismicity and active fault patterns in north China indicate that deformation occurs mainly along the borders of large tectonic blocks. The source region for the geoelectric signals appears to lie within a large shear zone, at the edge of a tectonic block undergoing rotation. The Tangshan epicentral area is thus only part of a larger zone of deformation. We suggest that dilational strain associated with the opening of fractures may lower resistivity and water table. For shallow crustal depths, such as those monitored by the Chinese geoelectric network, dilation and resistivity changes are expected to begin at stress levels well below the peak values of the seismic cycle. Our study suggests that in some cases the areal extent of geoelectric signals may be significantly larger than that of the eventual earthquake source dimension. The Chinese geoelectric database offers an opportunity to improve our understanding of possible geoelectric precursors to earthquakes.

Chromosomes of the Parasitic Isopod Anilocra Physodes

AbstractCounts of mitotic chromosomes have allowed to determine 2n = 12 as the modal diploid number of Anilocra physodes. Application of the C-banding technique reveals that two hetero-chromatic blocks bordering the centromeric region occur in each chromosome. This supports the notion that the actual low chromosome number of A. physodes may have been derived through a process of Robertsonian fusion.

Rubber-Sheeting Algorithm for Cadastral Maps

This paper presents a fast and efficient algorithm to homogeneously spread distortions generated by the conversion of paper maps to digital information. These distortions occur at the block borders as a result of junction adjustment, edge matching, and line adjustment. The sources of data are vectorized maps from adjacent scanned sheets, not necessarily of the same scale or with the same accuracy, which will be part of a future geographical information system (GIS) database. The algorithm has four stages, and resembles the spreading of soap bubbles limited by a polygonal ring changing its shape and size. An example illustrating the proposed procedure is given.

The Reverse Bordering Method

The bordering method allows recursive computation of the solution of a system of linear equations by adding one new row and one new column at each step of the procedure. When some of the intermediate systems are nearly singular, it is possible, by the block bordering method, to add several new rows and columns simultaneously. However, in that case, the solutions of some of the intermediate systems are not computed. The reverse bordering method allows computation of the solutions of these systems afterwards. Such a procedure has many applications in numerical analysis, that include orthogonal polynomials, Pade approximation, and the progressive forms of extrapolation processes.

Matrix recursive projection and interpolation algorithms

The Schur complement is used with the block bordering method to derive two recursive algorithms called the matrix recursive projection algorithm and the matrix recursive interpolation algorithm. These algorithms are extensions of the RPA and the RIA studied by Brezinski in the vector case. Some properties of these algorithms are given.

Singular rules for a multivariate quotient-difference algorithm

Using the multivariateqdg-algorithm developed in [5], it is possible to compute the partial numerators and denominators of a continued fraction representation associated with a descending staircase in a table of multivariate rational interpolants, more precisely, multivariate Newton-Pade approximants. The algorithm is only applicable if every three successive elements on the staircase are different. If a singularity occurs in the defining system of equations for the multivariate rational interpolant then singular rules must be developed. For the univariate Newton-Pade approximant this was done in [3] by Claessens and Wuytack. The idea to perturb the initial staircase and walk around the block structure in the table in order to avoid the singularity, is explored now in a multivariate setting. Another approach would be to use block bordering methods in combination with reverse bordering [4] in order to solve the rank deficient linear system of interpolation conditions (Newton-Pade approximation conditions) recursively. Since this last technique can also be used for scattered multivariate data exhibiting near-singularity, we describe the second approach in a separate paper [7]. Here we deal only with partially grid-structured data (satisfying the so-called rectangle rule or inclusion property).

Reinterpretation of the adsorption kinetics data measured by AES and XPS

A classical example of employing the methods of electronic spectroscopy in the study of chemisorption kinetics is the work on surface oxidation of iron and nickel. In the curve which plots the change of sticking coefficient versus surface coverage with oxygen, a characteristic minimum is seen for a coverage less than that on the surface most closely packed with oxygen atoms. As yet, the increase in sticking coefficient has been related to the formation of oxide nuclei. In this work, a model is suggested that elucidates the observed relation between surface coverage and oxygen exposure. This model refers to the actual mosaic structure of monocrystalline metal samples. It is assumed that due to their mobile diffusion, the oxygen atoms can occupy positions not only on the surface, but also on the borders of mosaic blocks. The model was examined by studying the kinetics of Fe(111) surface oxidation and of low-temperature sulfur segregation on that surface. About 4 × 10 14 sites per 1 cm 2 of surface area were determined to be available for sulfur adsorption at the borders of mosaic blocks.

A breakdown-free Lanczos type algorithm for solving linear systems

Lanczos type algorithms for solving systems of linear equations have their foundations in the theory of formal orthogonal polynomials and the method of moments which leads to a determinantal formula for their iterates. The various Lanczos type algorithms mainly differ by the way of computing the coefficients entering into the recurrence formulae. If the denominator in the formula for one of these coefficients is zero, then a breakdown occurs in the algorithm, and it must be stopped. Such a breakdown is in fact due to the non-existence of some orthogonal polynomial. In this paper we show how to jump over such a singularity by computing the next existing orthogonal polynomial by the block bordering method. The resulting algorithm, called MRZ, is equivalent to the nongeneric BIODIR algorithm (which is a look-ahead Lanczos type algorithm), but our derivation is much simpler.