Probabilistic frequency variations of structure-soil systems

International Nuclear Information System (INIS)

Hamilton, C.W.; Hadjian, A.H.

1976-01-01

During earthquakes, structure-soil systems act as filters greatly amplifying the response of equipment whose frequencies are at or near their natural frequencies. Thus, the estimation of these structure-soil system frequencies assumes significant importance both for safety and cost. Actual in-situ frequencies of structures differ from calculated frequencies due both to variations in mathematical modelling techniques and to variations of material properties. This paper studies the second source only. This variability is usually gauged by the 'worst case' analyses technique in which extreme high- and low- parameter values are assumed and the associated frequencies are used as upper and lower bounds. This approach is not entirely satisfactory because it does not provide any indication of the probability of these limits being exceeded, of the distribution between these limits, or of the level of conservation introduced into the design process. The present approach provides this additional information. The emphasis in this part is both on developing the methodology and on the results obtained. It covers both the fixed-base structure and the effects of soil-structure interaction. Empirical data on concrete proerties were obtained from previously published results. Much less is known about variability of soil properties, so the soil structure interaction coefficients are assumed to be normally distributed. As data on the variation of soil properties become available, they can be readily incorporated via the methodology developed here. (Auth.)

Structured approaches to large-scale systems: Variational integrators for interconnected Lagrange-Dirac systems and structured model reduction on Lie groups

Science.gov (United States)

Parks, Helen Frances

This dissertation presents two projects related to the structured integration of large-scale mechanical systems. Structured integration uses the considerable differential geometric structure inherent in mechanical motion to inform the design of numerical integration schemes. This process improves the qualitative properties of simulations and becomes especially valuable as a measure of accuracy over long time simulations in which traditional Gronwall accuracy estimates lose their meaning. Often, structured integration schemes replicate continuous symmetries and their associated conservation laws at the discrete level. Such is the case for variational integrators, which discretely replicate the process of deriving equations of motion from variational principles. This results in the conservation of momenta associated to symmetries in the discrete system and conservation of a symplectic form when applicable. In the case of Lagrange-Dirac systems, variational integrators preserve a discrete analogue of the Dirac structure preserved in the continuous flow. In the first project of this thesis, we extend Dirac variational integrators to accommodate interconnected systems. We hope this work will find use in the fields of control, where a controlled system can be thought of as a "plant" system joined to its controller, and in the approach of very large systems, where modular modeling may prove easier than monolithically modeling the entire system. The second project of the thesis considers a different approach to large systems. Given a detailed model of the full system, can we reduce it to a more computationally efficient model without losing essential geometric structures in the system? Asked without the reference to structure, this is the essential question of the field of model reduction. The answer there has been a resounding yes, with Principal Orthogonal Decomposition (POD) with snapshots rising as one of the most successful methods. Our project builds on previous work

Variational Level Set Method for Two-Stage Image Segmentation Based on Morphological Gradients

Directory of Open Access Journals (Sweden)

Zemin Ren

2014-01-01

Full Text Available We use variational level set method and transition region extraction techniques to achieve image segmentation task. The proposed scheme is done by two steps. We first develop a novel algorithm to extract transition region based on the morphological gradient. After this, we integrate the transition region into a variational level set framework and develop a novel geometric active contour model, which include an external energy based on transition region and fractional order edge indicator function. The external energy is used to drive the zero level set toward the desired image features, such as object boundaries. Due to this external energy, the proposed model allows for more flexible initialization. The fractional order edge indicator function is incorporated into the length regularization term to diminish the influence of noise. Moreover, internal energy is added into the proposed model to penalize the deviation of the level set function from a signed distance function. The results evolution of the level set function is the gradient flow that minimizes the overall energy functional. The proposed model has been applied to both synthetic and real images with promising results.

Child Development and Structural Variation in the Human Genome

Science.gov (United States)

Zhang, Ying; Haraksingh, Rajini; Grubert, Fabian; Abyzov, Alexej; Gerstein, Mark; Weissman, Sherman; Urban, Alexander E.

2013-01-01

Structural variation of the human genome sequence is the insertion, deletion, or rearrangement of stretches of DNA sequence sized from around 1,000 to millions of base pairs. Over the past few years, structural variation has been shown to be far more common in human genomes than previously thought. Very little is currently known about the effects…

A Variational Level Set Model Combined with FCMS for Image Clustering Segmentation

Directory of Open Access Journals (Sweden)

Liming Tang

2014-01-01

Full Text Available The fuzzy C means clustering algorithm with spatial constraint (FCMS is effective for image segmentation. However, it lacks essential smoothing constraints to the cluster boundaries and enough robustness to the noise. Samson et al. proposed a variational level set model for image clustering segmentation, which can get the smooth cluster boundaries and closed cluster regions due to the use of level set scheme. However it is very sensitive to the noise since it is actually a hard C means clustering model. In this paper, based on Samson’s work, we propose a new variational level set model combined with FCMS for image clustering segmentation. Compared with FCMS clustering, the proposed model can get smooth cluster boundaries and closed cluster regions due to the use of level set scheme. In addition, a block-based energy is incorporated into the energy functional, which enables the proposed model to be more robust to the noise than FCMS clustering and Samson’s model. Some experiments on the synthetic and real images are performed to assess the performance of the proposed model. Compared with some classical image segmentation models, the proposed model has a better performance for the images contaminated by different noise levels.

SV2: accurate structural variation genotyping and de novo mutation detection from whole genomes.

Science.gov (United States)

Antaki, Danny; Brandler, William M; Sebat, Jonathan

2018-05-15

Structural variation (SV) detection from short-read whole genome sequencing is error prone, presenting significant challenges for population or family-based studies of disease. Here, we describe SV2, a machine-learning algorithm for genotyping deletions and duplications from paired-end sequencing data. SV2 can rapidly integrate variant calls from multiple structural variant discovery algorithms into a unified call set with high genotyping accuracy and capability to detect de novo mutations. SV2 is freely available on GitHub (https://github.com/dantaki/SV2). jsebat@ucsd.edu. Supplementary data are available at Bioinformatics online.

Variational identities and Hamiltonian structures

International Nuclear Information System (INIS)

Ma Wenxiu

2010-01-01

This report is concerned with Hamiltonian structures of classical and super soliton hierarchies. In the classical case, basic tools are variational identities associated with continuous and discrete matrix spectral problems, targeted to soliton equations derived from zero curvature equations over general Lie algebras, both semisimple and non-semisimple. In the super case, a supertrace identity is presented for constructing Hamiltonian structures of super soliton equations associated with Lie superalgebras. We illustrate the general theories by the KdV hierarchy, the Volterra lattice hierarchy, the super AKNS hierarchy, and two hierarchies of dark KdV equations and dark Volterra lattices. The resulting Hamiltonian structures show the commutativity of each hierarchy discussed and thus the existence of infinitely many commuting symmetries and conservation laws.

Fourier transform and mean quadratic variation of Bernoulli convolution on homogeneous Cantor set

Energy Technology Data Exchange (ETDEWEB)

Yu Zuguo E-mail: yuzg@hotmail.comz.yu

2004-07-01

For the Bernoulli convolution on homogeneous Cantor set, under some condition, it is proved that the mean quadratic variation and the average of Fourier transform of this measure are bounded above and below.

Systems of general nonlinear set-valued mixed variational inequalities problems in Hilbert spaces

Directory of Open Access Journals (Sweden)

Cho Yeol

2011-01-01

Full Text Available Abstract In this paper, the existing theorems and methods for finding solutions of systems of general nonlinear set-valued mixed variational inequalities problems in Hilbert spaces are studied. To overcome the difficulties, due to the presence of a proper convex lower semi-continuous function, φ and a mapping g, which appeared in the considered problem, we have used some applications of the resolvent operator technique. We would like to point out that although many authors have proved results for finding solutions of the systems of nonlinear set-valued (mixed variational inequalities problems, it is clear that it cannot be directly applied to the problems that we have considered in this paper because of φ and g. 2000 AMS Subject Classification: 47H05; 47H09; 47J25; 65J15.

EqualChance: Addressing Intra-set Write Variation to Increase Lifetime of Non-volatile Caches

Energy Technology Data Exchange (ETDEWEB)

Mittal, Sparsh [ORNL; Vetter, Jeffrey S [ORNL

2014-01-01

To address the limitations of SRAM such as high-leakage and low-density, researchers have explored use of non-volatile memory (NVM) devices, such as ReRAM (resistive RAM) and STT-RAM (spin transfer torque RAM) for designing on-chip caches. A crucial limitation of NVMs, however, is that their write endurance is low and the large intra-set write variation introduced by existing cache management policies may further exacerbate this problem, thereby reducing the cache lifetime significantly. We present EqualChance, a technique to increase cache lifetime by reducing intra-set write variation. EqualChance works by periodically changing the physical cache-block location of a write-intensive data item within a set to achieve wear-leveling. Simulations using workloads from SPEC CPU2006 suite and HPC (high-performance computing) field show that EqualChance improves the cache lifetime by 4.29X. Also, its implementation overhead is small, and it incurs very small performance and energy loss.

Landscape and variation of RNA secondary structure across the human transcriptome.

OpenAIRE

Wan, Y; Qu, K; Zhang, QC; Flynn, RA; Manor, O; Ouyang, Z; Zhang, J; Spitale, RC; Snyder, MP; Segal, E; Chang, HY

2014-01-01

In parallel to the genetic code for protein synthesis, a second layer of information is embedded in all RNA transcripts in the form of RNA structure. RNA structure influences practically every step in the gene expression program. However, the nature of most RNA structures or effects of sequence variation on structure are not known. Here we report the initial landscape and variation of RNA secondary structures (RSSs) in a human family trio (mother, father and their child). This provides a comp...

GENETIC STRUCTURE OF NORWAY SPRUCE (PICEA ABIES): CONCORDANCE OF MORPHOLOGICAL AND ALLOZYMIC VARIATION.

Science.gov (United States)

Lagercrantz, Ulf; Ryman, Nils

1990-02-01

This study describes the population structure of Norway spruce (Picea abies) as revealed by protein polymorphisms and morphological variation. Electrophoretically detectable genetic variability was examined at 22 protein loci in 70 populations from the natural range of the species in Europe. Like other conifers, Norway spruce exhibits a relatively large amount of genetic variability and little differentiation among populations. Sixteen polymorphic loci (73%) segregate for a total of 51 alleles, and average heterozygosity per population is 0.115. Approximately 5% of the total genetic diversity is explained by differences between populations (G ST = 0.052), and Nei's standard genetic distance is less than 0.04 in all cases. We suggest that the population structure largely reflects relatively recent historical events related to the last glaciation and that Norway spruce is still in a process of adaptation and differentiation. There is a clear geographic pattern in the variation of allele frequencies. A major part of the allelefrequency variation can be accounted for by a few synthetic variables (principal components), and 80% of the variation of the first principal component is "explained" by latitude and longitude. The central European populations are consistently depauperate of genetic variability, most likely as an effect of severe restrictions of population size during the last glaciation. The pattern of differentiation at protein loci is very similar to that observed for seven morphological traits examined. This similarity suggests that the same evolutionary forces have acted upon both sets of characters. © 1990 The Society for the Study of Evolution.

Structural variations and physical properties of lignin coke

International Nuclear Information System (INIS)

Otani, C.

1986-01-01

The studied lignin is a by-product of the process of ethanol production from eucaliptus. It was heat-treated under inert atmosphere conditions at increasing temperatures from 300 0 C up to 2600 0 C. This material has about 35 weight % of carbon yield and low ash content (0.70 w %). The structural variations were studied by wide-angle X-ray diffraction, small-angle X-ray scattering and infra-red spectroscopy. The bulk and the ''real'' density of the samples have also been determined as a function of the heat treatment temperatures. These experimental results enabled us to establish a mechanism of structure variation based on the formation of a graphite-like and porous structure within the initially amorphous lignin matrix. It has been possible to specify the adequate heat treatment temperature based upon the lignin coke applications. (author) [pt

Unconfined versus confined speleogenetic settings: variations of solution porosity.

Directory of Open Access Journals (Sweden)

Klimchouk Alexander

2006-01-01

Full Text Available Speleogenesis in confined settings generates cave morphologies that differ much from those formed in unconfined settings. Cavesdeveloped in unconfined settings are characterised by broadly dendritic patterns of channels due to highly competing development.In contrast, caves originated under confined conditions tend to form two- or three-dimensional mazes with densely packed conduits.This paper illustrates variations of solution (channel porosity resulted from speleogenesis in unconfined and confined settings by theanalysis of morphometric parameters of typical cave patterns. Two samples of typical cave systems formed in the respective settingsare compared. The sample that represents unconfined speleogenesis consists of solely limestone caves, whereas gypsum cavesof this type tend to be less dendritic and more linear. The sample that represents confined speleogenesis consists of both limestoneand gypsum maze caves. The comparison shows considerable differences in average values of some parameters between thesettings. Passage network density (the ratio of the cave length to the area of the cave field, km/km2 is one order of magnitudegreater in confined settings than in unconfined (average 167.3 km/km2 versus 16.6 km/km2. Similarly, an order of magnitudedifference is observed in cave porosity (a fraction of the volume of a cave block, occupied by mapped cavities; 5.0 % versus 0.4 %.This illustrates that storage in maturely karstified confined aquifers is generally much greater than in unconfined. The average areal coverage (a fraction of the area of the cave field occupied by passages in a plan view is about 5 times greater in confined settingsthan in unconfined (29.7 % versus 6.4 %. This indicates that conduit permeability in confined aquifers is appreciably easier to targetwith drilling than the widely spaced conduits in unconfined aquifers.

The story turned upside down: Meaning effects linked to variations on narrative structure

DEFF Research Database (Denmark)

Bundgaard, Peer; Østergaard, Svend

2007-01-01

be subject to variations in view of yielding specific meaning effects. This is because the production and reception of a narrative is a dynamic process where physical forces, modal forces and intentions set up a space of possibilities for the narrative trajectory. We therefore propose a determination...... structure is indeed driven by an inverted narrative schema and each significant event in the story but one (as well as each physical paragraph but one) has its rigorously symmetrical counterpart. Moreover, this inverted schema can be explained in terms of the modal forces at stake in the narrative....

Towards Structural Analysis of Audio Recordings in the Presence of Musical Variations

Directory of Open Access Journals (Sweden)

Müller Meinard

2007-01-01

Full Text Available One major goal of structural analysis of an audio recording is to automatically extract the repetitive structure or, more generally, the musical form of the underlying piece of music. Recent approaches to this problem work well for music, where the repetitions largely agree with respect to instrumentation and tempo, as is typically the case for popular music. For other classes of music such as Western classical music, however, musically similar audio segments may exhibit significant variations in parameters such as dynamics, timbre, execution of note groups, modulation, articulation, and tempo progression. In this paper, we propose a robust and efficient algorithm for audio structure analysis, which allows to identify musically similar segments even in the presence of large variations in these parameters. To account for such variations, our main idea is to incorporate invariance at various levels simultaneously: we design a new type of statistical features to absorb microvariations, introduce an enhanced local distance measure to account for local variations, and describe a new strategy for structure extraction that can cope with the global variations. Our experimental results with classical and popular music show that our algorithm performs successfully even in the presence of significant musical variations.

Structural level set inversion for microwave breast screening

International Nuclear Information System (INIS)

Irishina, Natalia; Álvarez, Diego; Dorn, Oliver; Moscoso, Miguel

2010-01-01

We present a new inversion strategy for the early detection of breast cancer from microwave data which is based on a new multiphase level set technique. This novel structural inversion method uses a modification of the color level set technique adapted to the specific situation of structural breast imaging taking into account the high complexity of the breast tissue. We only use data of a few microwave frequencies for detecting the tumors hidden in this complex structure. Three level set functions are employed for describing four different types of breast tissue, where each of these four regions is allowed to have a complicated topology and to have an interior structure which needs to be estimated from the data simultaneously with the region interfaces. The algorithm consists of several stages of increasing complexity. In each stage more details about the anatomical structure of the breast interior is incorporated into the inversion model. The synthetic breast models which are used for creating simulated data are based on real MRI images of the breast and are therefore quite realistic. Our results demonstrate the potential and feasibility of the proposed level set technique for detecting, locating and characterizing a small tumor in its early stage of development embedded in such a realistic breast model. Both the data acquisition simulation and the inversion are carried out in 2D

Lipschitz equivalence of self-similar sets with touching structures

International Nuclear Information System (INIS)

Ruan, Huo-Jun; Wang, Yang; Xi, Li-Feng

2014-01-01

Lipschitz equivalence of self-similar sets is an important area in the study of fractal geometry. It is known that two dust-like self-similar sets with the same contraction ratios are always Lipschitz equivalent. However, when self-similar sets have touching structures the problem of Lipschitz equivalence becomes much more challenging and intriguing at the same time. So far, all the known results only cover self-similar sets in R with no more than three branches. In this study we establish results for the Lipschitz equivalence of self-similar sets with touching structures in R with arbitrarily many branches. Key to our study is the introduction of a geometric condition for self-similar sets called substitutable. (paper)

Hierarchical sets: analyzing pangenome structure through scalable set visualizations

Science.gov (United States)

2017-01-01

Abstract Motivation: The increase in available microbial genome sequences has resulted in an increase in the size of the pangenomes being analyzed. Current pangenome visualizations are not intended for the pangenome sizes possible today and new approaches are necessary in order to convert the increase in available information to increase in knowledge. As the pangenome data structure is essentially a collection of sets we explore the potential for scalable set visualization as a tool for pangenome analysis. Results: We present a new hierarchical clustering algorithm based on set arithmetics that optimizes the intersection sizes along the branches. The intersection and union sizes along the hierarchy are visualized using a composite dendrogram and icicle plot, which, in pangenome context, shows the evolution of pangenome and core size along the evolutionary hierarchy. Outlying elements, i.e. elements whose presence pattern do not correspond with the hierarchy, can be visualized using hierarchical edge bundles. When applied to pangenome data this plot shows putative horizontal gene transfers between the genomes and can highlight relationships between genomes that is not represented by the hierarchy. We illustrate the utility of hierarchical sets by applying it to a pangenome based on 113 Escherichia and Shigella genomes and find it provides a powerful addition to pangenome analysis. Availability and Implementation: The described clustering algorithm and visualizations are implemented in the hierarchicalSets R package available from CRAN (https://cran.r-project.org/web/packages/hierarchicalSets) Contact: thomasp85@gmail.com Supplementary information: Supplementary data are available at Bioinformatics online. PMID:28130242

Canonical variate regression.

Science.gov (United States)

Luo, Chongliang; Liu, Jin; Dey, Dipak K; Chen, Kun

2016-07-01

In many fields, multi-view datasets, measuring multiple distinct but interrelated sets of characteristics on the same set of subjects, together with data on certain outcomes or phenotypes, are routinely collected. The objective in such a problem is often two-fold: both to explore the association structures of multiple sets of measurements and to develop a parsimonious model for predicting the future outcomes. We study a unified canonical variate regression framework to tackle the two problems simultaneously. The proposed criterion integrates multiple canonical correlation analysis with predictive modeling, balancing between the association strength of the canonical variates and their joint predictive power on the outcomes. Moreover, the proposed criterion seeks multiple sets of canonical variates simultaneously to enable the examination of their joint effects on the outcomes, and is able to handle multivariate and non-Gaussian outcomes. An efficient algorithm based on variable splitting and Lagrangian multipliers is proposed. Simulation studies show the superior performance of the proposed approach. We demonstrate the effectiveness of the proposed approach in an [Formula: see text] intercross mice study and an alcohol dependence study. © The Author 2016. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

A Set of Plastid Loci for Use in Multiplex Fragment Length Genotyping for Intraspecific Variation in Pinus (Pinaceae

Directory of Open Access Journals (Sweden)

Austin M. Wofford

2014-04-01

Full Text Available Premise of the study: Recently released Pinus plastome sequences support characterization of 15 plastid simple sequence repeat (cpSSR loci originally published for P. contorta and P. thunbergii. This allows selection of loci for single-tube PCR multiplexed genotyping in any subsection of the genus. Methods: Unique placement of primers and primer conservation across the genus were investigated, and a set of six loci were selected for single-tube multiplexing. We compared interspecific variation between cpSSRs and nucleotide sequences ofycf1 and tested intraspecific variation for cpSSRs using 911 samples in the P. ponderosa species complex. Results: The cpSSR loci contain mononucleotide and complex repeats with additional length variation in flanking regions. They are not located in hypervariable regions, and most primers are conserved across the genus. A single PCR per sample multiplexed for six loci yielded 45 alleles in 911 samples. Discussion: The protocol allows efficient genotyping of many samples. The cpSSR loci are too variable for Pinus phylogenies but are useful for the study of genetic structure within and among populations. The multiplex method could easily be extended to other plant groups by choosing primers for cpSSR loci in a plastome alignment for the target group.

Temporal variation in bat-fruit interactions: Foraging strategies influence network structure over time

Science.gov (United States)

Zapata-Mesa, Natalya; Montoya-Bustamante, Sebastián; Murillo-García, Oscar E.

2017-11-01

Mutualistic interactions, such as seed dispersal, are important for the maintenance of structure and stability of tropical communities. However, there is a lack of information about spatial and temporal variation in plant-animal interaction networks. Thus, our goal was to assess the effect of bat's foraging strategies on temporal variation in the structure and robustness of bat-fruit networks in both a dry and a rain tropical forest. We evaluated monthly variation in bat-fruit networks by using seven structure metrics: network size, average path length, nestedness, modularity, complementary specialization, normalized degree and betweenness centrality. Seed dispersal networks showed variations in size, species composition and modularity; did not present nested structures and their complementary specialization was high compared to other studies. Both networks presented short path lengths, and a constantly high robustness, despite their monthly variations. Sedentary bat species were recorded during all the study periods and occupied more central positions than nomadic species. We conclude that foraging strategies are important structuring factors that affect the dynamic of networks by determining the functional roles of frugivorous bats over time; thus sedentary bats are more important than nomadic species for the maintenance of the network structure, and their conservation is a must.

Variation in assessment and standard setting practices across UK undergraduate medicine and the need for a benchmark.

Science.gov (United States)

MacDougall, Margaret

2015-10-31

The principal aim of this study is to provide an account of variation in UK undergraduate medical assessment styles and corresponding standard setting approaches with a view to highlighting the importance of a UK national licensing exam in recognizing a common standard. Using a secure online survey system, response data were collected during the period 13 - 30 January 2014 from selected specialists in medical education assessment, who served as representatives for their respective medical schools. Assessment styles and corresponding choices of standard setting methods vary markedly across UK medical schools. While there is considerable consensus on the application of compensatory approaches, individual schools display their own nuances through use of hybrid assessment and standard setting styles, uptake of less popular standard setting techniques and divided views on norm referencing. The extent of variation in assessment and standard setting practices across UK medical schools validates the concern that there is a lack of evidence that UK medical students achieve a common standard on graduation. A national licensing exam is therefore a viable option for benchmarking the performance of all UK undergraduate medical students.

Landscape and variation of RNA secondary structure across the human transcriptome.

Science.gov (United States)

Wan, Yue; Qu, Kun; Zhang, Qiangfeng Cliff; Flynn, Ryan A; Manor, Ohad; Ouyang, Zhengqing; Zhang, Jiajing; Spitale, Robert C; Snyder, Michael P; Segal, Eran; Chang, Howard Y

2014-01-30

In parallel to the genetic code for protein synthesis, a second layer of information is embedded in all RNA transcripts in the form of RNA structure. RNA structure influences practically every step in the gene expression program. However, the nature of most RNA structures or effects of sequence variation on structure are not known. Here we report the initial landscape and variation of RNA secondary structures (RSSs) in a human family trio (mother, father and their child). This provides a comprehensive RSS map of human coding and non-coding RNAs. We identify unique RSS signatures that demarcate open reading frames and splicing junctions, and define authentic microRNA-binding sites. Comparison of native deproteinized RNA isolated from cells versus refolded purified RNA suggests that the majority of the RSS information is encoded within RNA sequence. Over 1,900 transcribed single nucleotide variants (approximately 15% of all transcribed single nucleotide variants) alter local RNA structure. We discover simple sequence and spacing rules that determine the ability of point mutations to impact RSSs. Selective depletion of 'riboSNitches' versus structurally synonymous variants at precise locations suggests selection for specific RNA shapes at thousands of sites, including 3' untranslated regions, binding sites of microRNAs and RNA-binding proteins genome-wide. These results highlight the potentially broad contribution of RNA structure and its variation to gene regulation.

THE MODEL OF IDENTIFICATION OF THE PROBLEM MAIN CAUSE SET OF VARIATION

Directory of Open Access Journals (Sweden)

Nenad Miric

2008-06-01

Full Text Available The term Lean has been widely used in today's product manufacturing and service delivery environments. In its fundamental nature the Lean Philosophy continuously strives for elimination of any kind of waste that exists in such environments. There are six basic strategies [1] related to the Lean Philosophy: Workplace Safety & Order & Cleanliness, JIT production, Six Sigma Quality, Empowered Teams, Visual Management and Pursuit of Perfection. On the journey of sustaining the lean supporting strategies there are many problems, or opportunities as Lean Practitioners call them. The value of some strategies highly depends on the efficiency of the problem solving techniques used to overcome the emerging issues. JIT production is difficult to imagine without a system that supports a high level of operational readiness with equipment uptime above 98%. Six Sigma level of quality, even when built into a product or system design, still undergoes the challenges of day to day operations and the variability brought with it. This variability is the source of waste and lean systems culture strives for continuous reduction of it. Empowered Teams properly trained to recognize the real cause of the problems and their Pursuit of Perfection culture are one of the corner stones of Lean Philosophy sustainability. Their ability to work with Problem Solvers and understand the difference between the "cure of the symptoms" approach versus "problem root cause identification" is one of the distinctions between Lean and Mass operations. Among the series of Statistical Engineering To ols this paper will show one of the techniques that proved to be powerful in the identification of the Set of Variation that contains the Main Cause of the new problems that arise in daily operations. This technique is called Multi - Vari. Multi - Vari is th e statistical engineering method used to analyze the set of data acquired in an organized manner. The set could be analyzed graphically or

A function space framework for structural total variation regularization with applications in inverse problems

Science.gov (United States)

Hintermüller, Michael; Holler, Martin; Papafitsoros, Kostas

2018-06-01

In this work, we introduce a function space setting for a wide class of structural/weighted total variation (TV) regularization methods motivated by their applications in inverse problems. In particular, we consider a regularizer that is the appropriate lower semi-continuous envelope (relaxation) of a suitable TV type functional initially defined for sufficiently smooth functions. We study examples where this relaxation can be expressed explicitly, and we also provide refinements for weighted TV for a wide range of weights. Since an integral characterization of the relaxation in function space is, in general, not always available, we show that, for a rather general linear inverse problems setting, instead of the classical Tikhonov regularization problem, one can equivalently solve a saddle-point problem where no a priori knowledge of an explicit formulation of the structural TV functional is needed. In particular, motivated by concrete applications, we deduce corresponding results for linear inverse problems with norm and Poisson log-likelihood data discrepancy terms. Finally, we provide proof-of-concept numerical examples where we solve the saddle-point problem for weighted TV denoising as well as for MR guided PET image reconstruction.

FEA of the Variations in Sound Insulation in Nominally Identical Prefabricated Lightweight Timber Panel Structures

DEFF Research Database (Denmark)

Kirkegaard, Poul Henning; Andersen, Lars

2013-01-01

The measurements of sound propagation in buildings usually show a variation between nominally identical constructed structures. These variations can be due to variations in structural properties, measurement uncertainties or workmanship related factors. Better knowledge about the source...... for these variations can lead to lowered production costs. The present paper presents a numerical analysis of the variations in sound propagation of norminally identical prefabricated lightweight timber panel structues. By using the commercial FEA software ABAQUS, a parameter study is carried out regarding variation...

A set of plastid loci for use in multiplex fragment length genotyping for intraspecific variation in Pinus (Pinaceae)1

Science.gov (United States)

Wofford, Austin M.; Finch, Kristen; Bigott, Adam; Willyard, Ann

2014-01-01

• Premise of the study: Recently released Pinus plastome sequences support characterization of 15 plastid simple sequence repeat (cpSSR) loci originally published for P. contorta and P. thunbergii. This allows selection of loci for single-tube PCR multiplexed genotyping in any subsection of the genus. • Methods: Unique placement of primers and primer conservation across the genus were investigated, and a set of six loci were selected for single-tube multiplexing. We compared interspecific variation between cpSSRs and nucleotide sequences of ycf1 and tested intraspecific variation for cpSSRs using 911 samples in the P. ponderosa species complex. • Results: The cpSSR loci contain mononucleotide and complex repeats with additional length variation in flanking regions. They are not located in hypervariable regions, and most primers are conserved across the genus. A single PCR per sample multiplexed for six loci yielded 45 alleles in 911 samples. • Discussion: The protocol allows efficient genotyping of many samples. The cpSSR loci are too variable for Pinus phylogenies but are useful for the study of genetic structure within and among populations. The multiplex method could easily be extended to other plant groups by choosing primers for cpSSR loci in a plastome alignment for the target group. PMID:25202625

Segmentation of teeth in CT volumetric dataset by panoramic projection and variational level set

Energy Technology Data Exchange (ETDEWEB)

Hosntalab, Mohammad [Islamic Azad University, Faculty of Engineering, Science and Research Branch, Tehran (Iran); Aghaeizadeh Zoroofi, Reza [University of Tehran, Control and Intelligent Processing Center of Excellence, School of Electrical and Computer Engineering, College of Engineering, Tehran (Iran); Abbaspour Tehrani-Fard, Ali [Islamic Azad University, Faculty of Engineering, Science and Research Branch, Tehran (Iran); Sharif University of Technology, Department of Electrical Engineering, Tehran (Iran); Shirani, Gholamreza [Faculty of Dentistry Medical Science of Tehran University, Oral and Maxillofacial Surgery Department, Tehran (Iran)

2008-09-15

Quantification of teeth is of clinical importance for various computer assisted procedures such as dental implant, orthodontic planning, face, jaw and cosmetic surgeries. In this regard, segmentation is a major step. In this paper, we propose a method for segmentation of teeth in volumetric computed tomography (CT) data using panoramic re-sampling of the dataset in the coronal view and variational level set. The proposed method consists of five steps as follows: first, we extract a mask in a CT images using Otsu thresholding. Second, the teeth are segmented from other bony tissues by utilizing anatomical knowledge of teeth in the jaws. Third, the proposed method is followed by estimating the arc of the upper and lower jaws and panoramic re-sampling of the dataset. Separation of upper and lower jaws and initial segmentation of teeth are performed by employing the horizontal and vertical projections of the panoramic dataset, respectively. Based the above mentioned procedures an initial mask for each tooth is obtained. Finally, we utilize the initial mask of teeth and apply a Variational level set to refine initial teeth boundaries to final contours. The proposed algorithm was evaluated in the presence of 30 multi-slice CT datasets including 3,600 images. Experimental results reveal the effectiveness of the proposed method. In the proposed algorithm, the variational level set technique was utilized to trace the contour of the teeth. In view of the fact that, this technique is based on the characteristic of the overall region of the teeth image, it is possible to extract a very smooth and accurate tooth contour using this technique. In the presence of the available datasets, the proposed technique was successful in teeth segmentation compared to previous techniques. (orig.)

Segmentation of teeth in CT volumetric dataset by panoramic projection and variational level set

International Nuclear Information System (INIS)

Hosntalab, Mohammad; Aghaeizadeh Zoroofi, Reza; Abbaspour Tehrani-Fard, Ali; Shirani, Gholamreza

2008-01-01

Quantification of teeth is of clinical importance for various computer assisted procedures such as dental implant, orthodontic planning, face, jaw and cosmetic surgeries. In this regard, segmentation is a major step. In this paper, we propose a method for segmentation of teeth in volumetric computed tomography (CT) data using panoramic re-sampling of the dataset in the coronal view and variational level set. The proposed method consists of five steps as follows: first, we extract a mask in a CT images using Otsu thresholding. Second, the teeth are segmented from other bony tissues by utilizing anatomical knowledge of teeth in the jaws. Third, the proposed method is followed by estimating the arc of the upper and lower jaws and panoramic re-sampling of the dataset. Separation of upper and lower jaws and initial segmentation of teeth are performed by employing the horizontal and vertical projections of the panoramic dataset, respectively. Based the above mentioned procedures an initial mask for each tooth is obtained. Finally, we utilize the initial mask of teeth and apply a Variational level set to refine initial teeth boundaries to final contours. The proposed algorithm was evaluated in the presence of 30 multi-slice CT datasets including 3,600 images. Experimental results reveal the effectiveness of the proposed method. In the proposed algorithm, the variational level set technique was utilized to trace the contour of the teeth. In view of the fact that, this technique is based on the characteristic of the overall region of the teeth image, it is possible to extract a very smooth and accurate tooth contour using this technique. In the presence of the available datasets, the proposed technique was successful in teeth segmentation compared to previous techniques. (orig.)

Intraspecific phytochemical variation shapes community and population structure for specialist caterpillars.

Science.gov (United States)

Glassmire, Andrea E; Jeffrey, Christopher S; Forister, Matthew L; Parchman, Thomas L; Nice, Chris C; Jahner, Joshua P; Wilson, Joseph S; Walla, Thomas R; Richards, Lora A; Smilanich, Angela M; Leonard, Michael D; Morrison, Colin R; Simbaña, Wilmer; Salagaje, Luis A; Dodson, Craig D; Miller, Jim S; Tepe, Eric J; Villamarin-Cortez, Santiago; Dyer, Lee A

2016-10-01

Chemically mediated plant-herbivore interactions contribute to the diversity of terrestrial communities and the diversification of plants and insects. While our understanding of the processes affecting community structure and evolutionary diversification has grown, few studies have investigated how trait variation shapes genetic and species diversity simultaneously in a tropical ecosystem. We investigated secondary metabolite variation among subpopulations of a single plant species, Piper kelleyi (Piperaceae), using high-performance liquid chromatography (HPLC), to understand associations between plant phytochemistry and host-specialized caterpillars in the genus Eois (Geometridae: Larentiinae) and associated parasitoid wasps and flies. In addition, we used a genotyping-by-sequencing approach to examine the genetic structure of one abundant caterpillar species, Eois encina, in relation to host phytochemical variation. We found substantive concentration differences among three major secondary metabolites, and these differences in chemistry predicted caterpillar and parasitoid community structure among host plant populations. Furthermore, E. encina populations located at high elevations were genetically different from other populations. They fed on plants containing high concentrations of prenylated benzoic acid. Thus, phytochemistry potentially shapes caterpillar and wasp community composition and geographic variation in species interactions, both of which can contribute to diversification of plants and insects. © 2016 The Authors. New Phytologist © 2016 New Phytologist Trust.

On the Relationship between Variational Level Set-Based and SOM-Based Active Contours

Science.gov (United States)

Abdelsamea, Mohammed M.; Gnecco, Giorgio; Gaber, Mohamed Medhat; Elyan, Eyad

2015-01-01

Most Active Contour Models (ACMs) deal with the image segmentation problem as a functional optimization problem, as they work on dividing an image into several regions by optimizing a suitable functional. Among ACMs, variational level set methods have been used to build an active contour with the aim of modeling arbitrarily complex shapes. Moreover, they can handle also topological changes of the contours. Self-Organizing Maps (SOMs) have attracted the attention of many computer vision scientists, particularly in modeling an active contour based on the idea of utilizing the prototypes (weights) of a SOM to control the evolution of the contour. SOM-based models have been proposed in general with the aim of exploiting the specific ability of SOMs to learn the edge-map information via their topology preservation property and overcoming some drawbacks of other ACMs, such as trapping into local minima of the image energy functional to be minimized in such models. In this survey, we illustrate the main concepts of variational level set-based ACMs, SOM-based ACMs, and their relationship and review in a comprehensive fashion the development of their state-of-the-art models from a machine learning perspective, with a focus on their strengths and weaknesses. PMID:25960736

Structural variations in aromatic 2π-electron three-membered rings ...

Indian Academy of Sciences (India)

Abstract. Structural variations of different 2π-aromatic three-membered ring systems of main group ele- ments, especially group 14 and 13 elements as compared to the classical description of cyclopropenyl cation has been reviewed in this article. The structures of heavier analogues as well as group 13 analogues of cyclo-.

3D variational brain tumor segmentation using Dirichlet priors on a clustered feature set.

Science.gov (United States)

Popuri, Karteek; Cobzas, Dana; Murtha, Albert; Jägersand, Martin

2012-07-01

Brain tumor segmentation is a required step before any radiation treatment or surgery. When performed manually, segmentation is time consuming and prone to human errors. Therefore, there have been significant efforts to automate the process. But, automatic tumor segmentation from MRI data is a particularly challenging task. Tumors have a large diversity in shape and appearance with intensities overlapping the normal brain tissues. In addition, an expanding tumor can also deflect and deform nearby tissue. In our work, we propose an automatic brain tumor segmentation method that addresses these last two difficult problems. We use the available MRI modalities (T1, T1c, T2) and their texture characteristics to construct a multidimensional feature set. Then, we extract clusters which provide a compact representation of the essential information in these features. The main idea in this work is to incorporate these clustered features into the 3D variational segmentation framework. In contrast to previous variational approaches, we propose a segmentation method that evolves the contour in a supervised fashion. The segmentation boundary is driven by the learned region statistics in the cluster space. We incorporate prior knowledge about the normal brain tissue appearance during the estimation of these region statistics. In particular, we use a Dirichlet prior that discourages the clusters from the normal brain region to be in the tumor region. This leads to a better disambiguation of the tumor from brain tissue. We evaluated the performance of our automatic segmentation method on 15 real MRI scans of brain tumor patients, with tumors that are inhomogeneous in appearance, small in size and in proximity to the major structures in the brain. Validation with the expert segmentation labels yielded encouraging results: Jaccard (58%), Precision (81%), Recall (67%), Hausdorff distance (24 mm). Using priors on the brain/tumor appearance, our proposed automatic 3D variational

New Tests for Variations of the Fine Structure Constant

Science.gov (United States)

Prestage, John D.

1995-01-01

We describe a new test for possible variations of the fine structure constant, by comparisons of rates between clocks based on hyperfine transitions in alkali atomos with different atomic number Z. H- maser, Cs and Hg+ clocks have a different dependence on ia relativistic contributions of order (Z. Recent H-maser vs Hg+ clock comparison data improves laboratory limits on a time variation by 100-fold to giveFuture laser cooled clocks (Be+, Rb, Cs, Hg+, etc.), when compared, will yield the most senstive of all tests for.

On the structure of the set of coincidence points

Energy Technology Data Exchange (ETDEWEB)

Arutyunov, A V [Peoples Friendship University of Russia, Moscow (Russian Federation); Gel' man, B D [Voronezh State University (Russian Federation)

2015-03-31

We consider the set of coincidence points for two maps between metric spaces. Cardinality, metric and topological properties of the coincidence set are studied. We obtain conditions which guarantee that this set (a) consists of at least two points; (b) consists of at least n points; (c) contains a countable subset; (d) is uncountable. The results are applied to study the structure of the double point set and the fixed point set for multivalued contractions. Bibliography: 12 titles.

Structural genomic variation in ischemic stroke

Science.gov (United States)

Matarin, Mar; Simon-Sanchez, Javier; Fung, Hon-Chung; Scholz, Sonja; Gibbs, J. Raphael; Hernandez, Dena G.; Crews, Cynthia; Britton, Angela; Wavrant De Vrieze, Fabienne; Brott, Thomas G.; Brown, Robert D.; Worrall, Bradford B.; Silliman, Scott; Case, L. Douglas; Hardy, John A.; Rich, Stephen S.; Meschia, James F.; Singleton, Andrew B.

2008-01-01

Technological advances in molecular genetics allow rapid and sensitive identification of genomic copy number variants (CNVs). This, in turn, has sparked interest in the function such variation may play in disease. While a role for copy number mutations as a cause of Mendelian disorders is well established, it is unclear whether CNVs may affect risk for common complex disorders. We sought to investigate whether CNVs may modulate risk for ischemic stroke (IS) and to provide a catalog of CNVs in patients with this disorder by analyzing copy number metrics produced as a part of our previous genome-wide single-nucleotide polymorphism (SNP)-based association study of ischemic stroke in a North American white population. We examined CNVs in 263 patients with ischemic stroke (IS). Each identified CNV was compared with changes identified in 275 neurologically normal controls. Our analysis identified 247 CNVs, corresponding to 187 insertions (76%; 135 heterozygous; 25 homozygous duplications or triplications; 2 heterosomic) and 60 deletions (24%; 40 heterozygous deletions;3 homozygous deletions; 14 heterosomic deletions). Most alterations (81%) were the same as, or overlapped with, previously reported CNVs. We report here the first genome-wide analysis of CNVs in IS patients. In summary, our study did not detect any common genomic structural variation unequivocally linked to IS, although we cannot exclude that smaller CNVs or CNVs in genomic regions poorly covered by this methodology may confer risk for IS. The application of genome-wide SNP arrays now facilitates the evaluation of structural changes through the entire genome as part of a genome-wide genetic association study. PMID:18288507

DESIGN OF STRUCTURAL ELEMENTS IN THE EVENT OF THE PRE-SET RELIABILITY, REGULAR LOAD AND BEARING CAPACITY DISTRIBUTION

Directory of Open Access Journals (Sweden)

Tamrazyan Ashot Georgievich

2012-10-01

Full Text Available Accurate and adequate description of external influences and of the bearing capacity of the structural material requires the employment of the probability theory methods. In this regard, the characteristic that describes the probability of failure-free operation is required. The characteristic of reliability means that the maximum stress caused by the action of the load will not exceed the bearing capacity. In this paper, the author presents a solution to the problem of calculation of structures, namely, the identification of reliability of pre-set design parameters, in particular, cross-sectional dimensions. If the load distribution pattern is available, employment of the regularities of distributed functions make it possible to find the pattern of distribution of maximum stresses over the structure. Similarly, we can proceed to the design of structures of pre-set rigidity, reliability and stability in the case of regular load distribution. We consider the element of design (a monolithic concrete slab, maximum stress S which depends linearly on load q. Within a pre-set period of time, the probability will not exceed the values according to the Poisson law. The analysis demonstrates that the variability of the bearing capacity produces a stronger effect on relative sizes of cross sections of a slab than the variability of loads. It is therefore particularly important to reduce the coefficient of variation of the load capacity. One of the methods contemplates the truncation of the bearing capacity distribution by pre-culling the construction material.

Variational calculus with constraints on general algebroids

Energy Technology Data Exchange (ETDEWEB)

Grabowska, Katarzyna [Physics Department, Division of Mathematical Methods in Physics, University of Warsaw, Hoza 69, 00-681 Warszawa (Poland); Grabowski, Janusz [Institute of Mathematics, Polish Academy of Sciences, Sniadeckich 8, PO Box 21, 00-956 Warszawa (Poland)], E-mail: konieczn@fuw.edu.pl, E-mail: jagrab@impan.gov.pl

2008-05-02

Variational calculus on a vector bundle E equipped with a structure of a general algebroid is developed, together with the corresponding analogs of Euler-Lagrange equations. Constrained systems are introduced in the variational and geometrical settings. The constrained Euler-Lagrange equations are derived for analogs of holonomic, vakonomic and nonholonomic constraints. This general model covers the majority of first-order Lagrangian systems which are present in the literature and reduces to the standard variational calculus and the Euler-Lagrange equations in classical mechanics for E = TM.

Variational calculus with constraints on general algebroids

International Nuclear Information System (INIS)

Grabowska, Katarzyna; Grabowski, Janusz

2008-01-01

Variational calculus on a vector bundle E equipped with a structure of a general algebroid is developed, together with the corresponding analogs of Euler-Lagrange equations. Constrained systems are introduced in the variational and geometrical settings. The constrained Euler-Lagrange equations are derived for analogs of holonomic, vakonomic and nonholonomic constraints. This general model covers the majority of first-order Lagrangian systems which are present in the literature and reduces to the standard variational calculus and the Euler-Lagrange equations in classical mechanics for E = TM

Genomics technologies to study structural variations in the grapevine genome

Directory of Open Access Journals (Sweden)

Cardone Maria Francesca

2016-01-01

Full Text Available Grapevine is one of the most important crop plants in the world. Recently there was great expansion of genomics resources about grapevine genome, thus providing increasing efforts for molecular breeding. Current cultivars display a great level of inter-specific differentiation that needs to be investigated to reach a comprehensive understanding of the genetic basis of phenotypic differences, and to find responsible genes selected by cross breeding programs. While there have been significant advances in resolving the pattern and nature of single nucleotide polymorphisms (SNPs on plant genomes, few data are available on copy number variation (CNV. Furthermore association between structural variations and phenotypes has been described in only a few cases. We combined high throughput biotechnologies and bioinformatics tools, to reveal the first inter-varietal atlas of structural variation (SV for the grapevine genome. We sequenced and compared four table grape cultivars with the Pinot noir inbred line PN40024 genome as the reference. We detected roughly 8% of the grapevine genome affected by genomic variations. Taken into account phenotypic differences existing among the studied varieties we performed comparison of SVs among them and the reference and next we performed an in-depth analysis of gene content of polymorphic regions. This allowed us to identify genes showing differences in copy number as putative functional candidates for important traits in grapevine cultivation.

Application of Bipolar Fuzzy Sets in Graph Structures

Directory of Open Access Journals (Sweden)

Muhammad Akram

2016-01-01

Full Text Available A graph structure is a useful tool in solving the combinatorial problems in different areas of computer science and computational intelligence systems. In this paper, we apply the concept of bipolar fuzzy sets to graph structures. We introduce certain notions, including bipolar fuzzy graph structure (BFGS, strong bipolar fuzzy graph structure, bipolar fuzzy Ni-cycle, bipolar fuzzy Ni-tree, bipolar fuzzy Ni-cut vertex, and bipolar fuzzy Ni-bridge, and illustrate these notions by several examples. We study ϕ-complement, self-complement, strong self-complement, and totally strong self-complement in bipolar fuzzy graph structures, and we investigate some of their interesting properties.

Inter-chromosomal variation in the pattern of human population genetic structure

Directory of Open Access Journals (Sweden)

Baye Tesfaye M

2011-05-01

Full Text Available Abstract Emerging technologies now make it possible to genotype hundreds of thousands of genetic variations in individuals, across the genome. The study of loci at finer scales will facilitate the understanding of genetic variation at genomic and geographic levels. We examined global and chromosomal variations across HapMap populations using 3.7 million single nucleotide polymorphisms to search for the most stratified genomic regions of human populations and linked these regions to ontological annotation and functional network analysis. To achieve this, we used five complementary statistical and genetic network procedures: principal component (PC, cluster, discriminant, fixation index (FST and network/pathway analyses. At the global level, the first two PC scores were sufficient to account for major population structure; however, chromosomal level analysis detected subtle forms of population structure within continental populations, and as many as 31 PCs were required to classify individuals into homogeneous groups. Using recommended population ancestry differentiation measures, a total of 126 regions of the genome were catalogued. Gene ontology and networks analyses revealed that these regions included the genes encoding oculocutaneous albinism II (OCA2, hect domain and RLD 2 (HERC2, ectodysplasin A receptor (EDAR and solute carrier family 45, member 2 (SLC45A2. These genes are associated with melanin production, which is involved in the development of skin and hair colour, skin cancer and eye pigmentation. We also identified the genes encoding interferon-γ (IFNG and death-associated protein kinase 1 (DAPK1, which are associated with cell death, inflammatory and immunological diseases. An in-depth understanding of these genomic regions may help to explain variations in adaptation to different environments. Our approach offers a comprehensive strategy for analysing chromosome-based population structure and differentiation, and demonstrates the

The NANOGrav Nine-year Data Set: Measurement and Analysis of Variations in Dispersion Measures

Energy Technology Data Exchange (ETDEWEB)

Jones, M. L.; McLaughlin, M. A.; Lam, M. T. [Department of Physics and Astronomy, West Virginia University, Morgantown, WV 26506 (United States); Cordes, J. M.; Chatterjee, S. [Department of Astronomy and Cornell Center for Astrophysics and Planetary Science, Cornell University, Ithaca, NY 14853 (United States); Levin, L. [Jodrell Bank Centre for Astrophysics, Alan Turing Building, School of Physics and Astronomy, The University of Manchester, Oxford Road, Manchester, M13 9PL (United Kingdom); Arzoumanian, Z. [Center for Research and Exploration in Space Science and Technology and X-Ray Astrophysics Laboratory, NASA Goddard Space Flight Center, Code 662, Greenbelt, MD 20771 (United States); Crowter, K.; Gonzalez, M. E. [Department of Physics and Astronomy, University of British Columbia, 6224 Agricultural Road, Vancouver, BC V6T 1Z1 (Canada); Demorest, P. B. [National Radio Astronomy Observatory, P.O. Box 0, Socorro, NM 87801 (United States); Dolch, T. [Department of Physics, Hillsdale College, 33 E. College Street, Hillsdale, MI 49242 (United States); Ellis, J. A; Lazio, T. J. W. [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Dr. Pasadena, CA 91109 (United States); Ferdman, R. D.; Fonseca, E. [Department of Physics, McGill University, 3600 rue Universite, Montreal, QC H3A 2T8 (Canada); Jones, G.; Pennucci, T. T. [Department of Physics, Columbia University, 550 W. 120th St. New York, NY 10027 (United States); Nice, D. J. [Department of Physics, Lafayette College, Easton, PA 18042 (United States); Ransom, S. M. [National Radio Astronomy Observatory, 520 Edgemont Road, Charlottesville, VA 22903 (United States); Stinebring, D. R. [Department of Physics and Astronomy, Oberlin College, Oberlin, OH 44074 (United States); and others

2017-06-01

We analyze dispersion measure (DM) variations of 37 millisecond pulsars in the nine-year North American Nanohertz Observatory for Gravitational Waves (NANOGrav) data release and constrain the sources of these variations. DM variations can result from a changing distance between Earth and the pulsar, inhomogeneities in the interstellar medium, and solar effects. Variations are significant for nearly all pulsars, with characteristic timescales comparable to or even shorter than the average spacing between observations. Five pulsars have periodic annual variations, 14 pulsars have monotonically increasing or decreasing trends, and 14 pulsars show both effects. Of the four pulsars with linear trends that have line-of-sight velocity measurements, three are consistent with a changing distance and require an overdensity of free electrons local to the pulsar. Several pulsars show correlations between DM excesses and lines of sight that pass close to the Sun. Mapping of the DM variations as a function of the pulsar trajectory can identify localized interstellar medium features and, in one case, an upper limit to the size of the dispersing region of 4 au. Four pulsars show roughly Kolmogorov structure functions (SFs), and another four show SFs less steep than Kolmogorov. One pulsar has too large an uncertainty to allow comparisons. We discuss explanations for apparent departures from a Kolmogorov-like spectrum, and we show that the presence of other trends and localized features or gradients in the interstellar medium is the most likely cause.

A genome wide survey of SNP variation reveals the genetic structure of sheep breeds.

Directory of Open Access Journals (Sweden)

James W Kijas

Full Text Available The genetic structure of sheep reflects their domestication and subsequent formation into discrete breeds. Understanding genetic structure is essential for achieving genetic improvement through genome-wide association studies, genomic selection and the dissection of quantitative traits. After identifying the first genome-wide set of SNP for sheep, we report on levels of genetic variability both within and between a diverse sample of ovine populations. Then, using cluster analysis and the partitioning of genetic variation, we demonstrate sheep are characterised by weak phylogeographic structure, overlapping genetic similarity and generally low differentiation which is consistent with their short evolutionary history. The degree of population substructure was, however, sufficient to cluster individuals based on geographic origin and known breed history. Specifically, African and Asian populations clustered separately from breeds of European origin sampled from Australia, New Zealand, Europe and North America. Furthermore, we demonstrate the presence of stratification within some, but not all, ovine breeds. The results emphasize that careful documentation of genetic structure will be an essential prerequisite when mapping the genetic basis of complex traits. Furthermore, the identification of a subset of SNP able to assign individuals into broad groupings demonstrates even a small panel of markers may be suitable for applications such as traceability.

Intensive Care Unit Structure Variation and Implications for Early Mobilization Practices. An International Survey.

Science.gov (United States)

Bakhru, Rita N; McWilliams, David J; Wiebe, Douglas J; Spuhler, Vicki J; Schweickert, William D

2016-09-01

Early mobilization (EM) improves outcomes for mechanically ventilated patients. Variation in structure and organizational characteristics may affect implementation of EM practices. We queried intensive care unit (ICU) environment and standardized ICU practices to evaluate organizational characteristics that enable EM practice. We recruited 151 ICUs in France, 150 in Germany, 150 in the United Kingdom, and 500 in the United States by telephone. Survey domains included respondent characteristics, hospital and ICU characteristics, and ICU practices and protocols. We surveyed 1,484 ICU leaders and received a 64% response rate (951 ICUs). Eighty-eight percent of respondents were in nursing leadership roles; the remainder were physiotherapists. Surveyed ICUs were predominantly mixed medical-surgical units (67%), and 27% were medical ICUs. ICU staffing models differed significantly (P equipment were highly variable among respondents. International ICU structure and practice is quite heterogeneous, and several factors (multidisciplinary rounds, setting daily goals for patients, presence of a dedicated physiotherapist, country, and nurse/patient staffing ratio) are significantly associated with the practice of EM. Practice and barriers may be far different based upon staffing structure. To achieve successful implementation, whether through trials or quality improvement, ICU staffing and practice patterns must be taken into account.

Lateral structural variation within the overlying plate and its correlation to the Tonankai earthquake

Science.gov (United States)

Fujie, G.; Nakanishi, A.; Park, J.; Obana, K.; Kodaira, S.; Kaneda, Y.

2009-12-01

Destructive interplate earthquakes have repeatedly occurred every 100-150 years beneath the Kumano-nada, off the Kii peninsula owing to the subduction of the Philippine Sea plate beneath the southwest Japan arc. The last great interplate earthquakes in this seismogenic subduction zone was the 1944 Tonankai earthquakes, and a number of coseismic slip distribution models derived from seismic and tsunami data show remarkable lateral variations along the trough axis. In 2006 and 2007, we conducted extensive wide-angle seismic refraction and reflection surveys in the entire rupture zone of the 1944 Tonankai earthquake. We designed two along-trough and two across-trench seismic survey lines and deployed a number of OBSs (Ocean Bottom Seismometers) with a spacing of 5km and fired an airgun array with a total volume of 200L at every 0.2km. The quality of the obtained wide-angle seismic record section is substantially good and we observed remarkable regional variation in the amplitude of refraction and reflection phases. For example, in some record sections, we can trace seismic signals up to the offset of more than 100 km, but in other sections, the airgun signals become dim at the offset of less than 30km. Such regional variation in the amplitude indicates the lateral variation of the seismic attenuation structure. For revealing lateral structural variation, we developed seismic structure models by the following approach. First, we applied the first arrival tomography for developing P-wave velocity structure models. Then, we imaged structural boundaries by the reflection traveltime mapping method. Finally, we developed seismic attenuation models by using raypaths and amplitude of first arrivals. Our seismic structure models showed remarkable along-trench structural variation. In the P-wave velocity models, we found a height on the subducting Philippine plate at the eastern end of the Kumano basin (south-east off Shima peninsula). In the western area (i.e. Kumano Basin

Solving Quasi-Variational Inequalities for Image Restoration with Adaptive Constraint Sets

KAUST Repository

Lenzen, F.

2014-01-01

© 2014 Society for Industrial and Applied Mathematics. We consider a class of quasi-variational inequalities (QVIs) for adaptive image restoration, where the adaptivity is described via solution-dependent constraint sets. In previous work we studied both theoretical and numerical issues. While we were able to show the existence of solutions for a relatively broad class of problems, we encountered difficulties concerning uniqueness of the solution as well as convergence of existing algorithms for solving QVIs. In particular, it seemed that with increasing image size the growing condition number of the involved differential operator posed severe problems. In the present paper we prove uniqueness for a larger class of problems, particularly independent of the image size. Moreover, we provide a numerical algorithm with proved convergence. Experimental results support our theoretical findings.

Variations in Crust and Upper Mantle Structure Beneath Diverse Geologic Provinces in Asia

National Research Council Canada - National Science Library

Schwartz, Susan H

1997-01-01

This report presents results of a two year effort to determine crust and mantle lithospheric structure beneath Eurasia and to explore the effects that structural variations have on regional wave propagation...

Time variation of the fine structure constant driven by quintessence

International Nuclear Information System (INIS)

Anchordoqui, Luis; Goldberg, Haim

2003-01-01

There are indications from the study of quasar absorption spectra that the fine structure constant α may have been measurably smaller for redshifts z>2. Analyses of other data ( 149 Sm fission rate for the Oklo natural reactor, variation of 187 Re β-decay rate in meteorite studies, atomic clock measurements) which probe variations of α in the more recent past imply much smaller deviations from its present value. In this work we tie the variation of α to the evolution of the quintessence field proposed by Albrecht and Skordis, and show that agreement with all these data, as well as consistency with Wilkinson Microwave Anisotropy Probe observations, can be achieved for a range of parameters. Some definite predictions follow for upcoming space missions searching for violations of the equivalence principle

Variation in mangrove forest structure and sediment characteristics in Bocas del Toro, Panama

Science.gov (United States)

Lovelock, C.E.; Feller, Ilka C.; McKee, K.L.; Thompson, R.

2005-01-01

Mangrove forest structure and sediment characteristics were examined in the extensive mangroves of Bocas del Toro, Republic of Panama. Forest structure was characterized to determine if spatial vegetation patterns were repeated over the Bocas del Toro landscape. Using a series of permanent plots and transects we found that the forests of Bocas del Toro were dominated by Rhizophora mangle with very few individuals of Avicennia germinans and Laguncularia racemosa. Despite this low species diversity, there was large variation in forest structure and in edaphic conditions (salinity, concentration of available phosphorus, Eh and sulphide concentration). Aboveground biomass varied 20-fold, from 6.8 Mg ha-1 in dwarf forests to 194.3 Mg ha-1 in the forests fringing the land. But variation in forest structure was predictable across the intertidal zone. There was a strong tree height gradient from seaward fringe (mean tree height 3.9 m), decreasing in stature in the interior dwarf forests (mean tree height 0.7 m), and increasing in stature in forests adjacent to the terrestrial forest (mean tree height 4.1 m). The predictable variation in forest structure emerges due to the complex interactions among edaphic and plant factors. Identifying predictable patterns in forest structure will aid in scaling up the ecosystem services provided by mangrove forests in coastal landscapes. Copyright 2005 College of Arts and Sciences.

Bats aloft: Variation in echolocation call structure at high altitudes

Science.gov (United States)

Bats alter their echolocation calls in response to changes in ecological and behavioral conditions, but little is known about how they adjust their call structure in response to changes in altitude. This study examines altitudinal variation in the echolocation calls of Brazilian free-tailed bats, T...

The story turned upside down: Meaning effects linked to variations on narrative structure

DEFF Research Database (Denmark)

Bundgaard, Peer; Østergaard, Svend

2007-01-01

This text has two parts. In the first section we intend to define the narrative schema—the canonical plot structure—as a symbolic form in Ernst Cassirer’s sense of the term. This basically implies that the narrative schema is not an invariant higher order combinatorial form, but may itself...... be subject to variations in view of yielding specific meaning effects. This is because the production and reception of a narrative is a dynamic process where physical forces, modal forces and intentions set up a space of possibilities for the narrative trajectory. We therefore propose a determination...... of the narrative schema in terms of “force dynamics.” In the next section we proceed to an analysis of Ernst Hemingway’s A Very Short Storyin order to illustrate this point. We lay down the main elements of its remarkable, if not simply outstanding both narrative and semantic-configurational structure: its plot...

Coupled variations of fundamental couplings and primordial nucleosynthesis

International Nuclear Information System (INIS)

Coc, Alain; Nunes, Nelson J.; Olive, Keith A.; Uzan, Jean-Philippe; Vangioni, Elisabeth

2006-10-01

The effect of variations of the fundamental nuclear parameters on big-bang nucleosynthesis are modeled and discussed in detail taking into account the interrelations between the fundamental parameters arising in unified theories. Considering only 4 He, strong constraints on the variation of the neutron lifetime, neutron-proton mass difference are set. These constraints are then translated into constraints on the time variation of the Yukawa couplings and the fine structure constant. Furthermore, we show that a variation of the deuterium binding energy is able to reconcile the 7 Li abundance deduced from the WMAP analysis with its spectroscopically determined value while maintaining concordance with D and 4 He. (authors)

Validation of the Amsterdam Dynamic Facial Expression Set--Bath Intensity Variations (ADFES-BIV: A Set of Videos Expressing Low, Intermediate, and High Intensity Emotions.

Directory of Open Access Journals (Sweden)

Tanja S H Wingenbach

Full Text Available Most of the existing sets of facial expressions of emotion contain static photographs. While increasing demand for stimuli with enhanced ecological validity in facial emotion recognition research has led to the development of video stimuli, these typically involve full-blown (apex expressions. However, variations of intensity in emotional facial expressions occur in real life social interactions, with low intensity expressions of emotions frequently occurring. The current study therefore developed and validated a set of video stimuli portraying three levels of intensity of emotional expressions, from low to high intensity. The videos were adapted from the Amsterdam Dynamic Facial Expression Set (ADFES and termed the Bath Intensity Variations (ADFES-BIV. A healthy sample of 92 people recruited from the University of Bath community (41 male, 51 female completed a facial emotion recognition task including expressions of 6 basic emotions (anger, happiness, disgust, fear, surprise, sadness and 3 complex emotions (contempt, embarrassment, pride that were expressed at three different intensities of expression and neutral. Accuracy scores (raw and unbiased (Hu hit rates were calculated, as well as response times. Accuracy rates above chance level of responding were found for all emotion categories, producing an overall raw hit rate of 69% for the ADFES-BIV. The three intensity levels were validated as distinct categories, with higher accuracies and faster responses to high intensity expressions than intermediate intensity expressions, which had higher accuracies and faster responses than low intensity expressions. To further validate the intensities, a second study with standardised display times was conducted replicating this pattern. The ADFES-BIV has greater ecological validity than many other emotion stimulus sets and allows for versatile applications in emotion research. It can be retrieved free of charge for research purposes from the

Validation of the Amsterdam Dynamic Facial Expression Set--Bath Intensity Variations (ADFES-BIV): A Set of Videos Expressing Low, Intermediate, and High Intensity Emotions.

Science.gov (United States)

Wingenbach, Tanja S H; Ashwin, Chris; Brosnan, Mark

2016-01-01

Most of the existing sets of facial expressions of emotion contain static photographs. While increasing demand for stimuli with enhanced ecological validity in facial emotion recognition research has led to the development of video stimuli, these typically involve full-blown (apex) expressions. However, variations of intensity in emotional facial expressions occur in real life social interactions, with low intensity expressions of emotions frequently occurring. The current study therefore developed and validated a set of video stimuli portraying three levels of intensity of emotional expressions, from low to high intensity. The videos were adapted from the Amsterdam Dynamic Facial Expression Set (ADFES) and termed the Bath Intensity Variations (ADFES-BIV). A healthy sample of 92 people recruited from the University of Bath community (41 male, 51 female) completed a facial emotion recognition task including expressions of 6 basic emotions (anger, happiness, disgust, fear, surprise, sadness) and 3 complex emotions (contempt, embarrassment, pride) that were expressed at three different intensities of expression and neutral. Accuracy scores (raw and unbiased (Hu) hit rates) were calculated, as well as response times. Accuracy rates above chance level of responding were found for all emotion categories, producing an overall raw hit rate of 69% for the ADFES-BIV. The three intensity levels were validated as distinct categories, with higher accuracies and faster responses to high intensity expressions than intermediate intensity expressions, which had higher accuracies and faster responses than low intensity expressions. To further validate the intensities, a second study with standardised display times was conducted replicating this pattern. The ADFES-BIV has greater ecological validity than many other emotion stimulus sets and allows for versatile applications in emotion research. It can be retrieved free of charge for research purposes from the corresponding author.

Sensitivity of ultracold-atom scattering experiments to variation of the fine-structure constant

International Nuclear Information System (INIS)

Borschevsky, A.; Beloy, K.; Flambaum, V. V.; Schwerdtfeger, P.

2011-01-01

We present numerical calculations for cesium and mercury to estimate the sensitivity of the scattering length to the variation of the fine-structure constant α. The method used follows the ideas of Chin and Flambaum [Phys. Rev. Lett. 96, 230801 (2006)], where the sensitivity to the variation of the electron-to-proton mass ratio β was considered. We demonstrate that for heavy systems, the sensitivity to the variation of α is of the same order of magnitude as to the variation of β. Near narrow Feshbach resonances, the enhancement of the sensitivity may exceed nine orders of magnitude.

Phylogenetic community structure: temporal variation in fish assemblage

OpenAIRE

Santorelli, Sergio; Magnusson, William; Ferreira, Efrem; Caramaschi, Erica; Zuanon, Jansen; Amadio, Sidnéia

2014-01-01

Hypotheses about phylogenetic relationships among species allow inferences about the mechanisms that affect species coexistence. Nevertheless, most studies assume that phylogenetic patterns identified are stable over time. We used data on monthly samples of fish from a single lake over 10 years to show that the structure in phylogenetic assemblages varies over time and conclusions depend heavily on the time scale investigated. The data set was organized in guild structures and temporal scales...

Incorporation of the Pore Size Variation to Modeling of the Elastic Behavior of Metallic Open-Cell Foams

Directory of Open Access Journals (Sweden)

Ćwieka K.

2017-03-01

Full Text Available In the present paper we present the approach for modeling of the elastic behavior of open-cell metallic foams concerning non-uniform pore size distribution. This approach combines design of foam structures and numerical simulations of compression tests using finite element method (FEM. In the design stage, Laguerre-Voronoi tessellations (LVT were performed on several sets of packed spheres with defined variation of radii, bringing about a set of foam structures with porosity ranging from 74 to 98% and different pore size variation quantified by the coefficient of pore volume variation, CV(V, from 0.5 to 2.1. Each structure was numerically subjected to uni-axial compression test along three directions within the elastic region. Basing on the numerical response, the effective Young’s modulus, Eeff, was calculated for each structure. It is shown that the Eeff is not only dependent on the porosity but also on the pore size variation.

The variation of the fine-structure constant from disformal couplings

Energy Technology Data Exchange (ETDEWEB)

De Bruck, Carsten van; Mifsud, Jurgen [Consortium for Fundamental Physics, School of Mathematics and Statistics, University of Sheffield, Hounsfield Road, Sheffield S3 7RH (United Kingdom); Nunes, Nelson J., E-mail: c.vandebruck@sheffield.ac.uk, E-mail: jmifsud1@sheffield.ac.uk, E-mail: njnunes@fc.ul.pt [Instituto de Astrofísica e Ciências do Espaço, Faculdade de Ciências da Universidade de Lisboa, Campo Grande, PT1749-016 Lisboa (Portugal)

2015-12-01

We study a theory in which the electromagnetic field is disformally coupled to a scalar field, in addition to a usual non-minimal electromagnetic coupling. We show that disformal couplings modify the expression for the fine-structure constant, α. As a result, the theory we consider can explain the non-zero reported variation in the evolution of α by purely considering disformal couplings. We also find that if matter and photons are coupled in the same way to the scalar field, disformal couplings itself do not lead to a variation of the fine-structure constant. A number of scenarios are discussed consistent with the current astrophysical, geochemical, laboratory and the cosmic microwave background radiation constraints on the cosmological evolution of α. The models presented are also consistent with the current type Ia supernovae constraints on the effective dark energy equation of state. We find that the Oklo bound in particular puts strong constraints on the model parameters. From our numerical results, we find that the introduction of a non-minimal electromagnetic coupling enhances the cosmological variation in α. Better constrained data is expected to be reported by ALMA and with the forthcoming generation of high-resolution ultra-stable spectrographs such as PEPSI, ESPRESSO, and ELT-HIRES. Furthermore, an expected increase in the sensitivity of molecular and nuclear clocks will put a more stringent constraint on the theory.

The variation of the fine-structure constant from disformal couplings

International Nuclear Information System (INIS)

De Bruck, Carsten van; Mifsud, Jurgen; Nunes, Nelson J.

2015-01-01

We study a theory in which the electromagnetic field is disformally coupled to a scalar field, in addition to a usual non-minimal electromagnetic coupling. We show that disformal couplings modify the expression for the fine-structure constant, α. As a result, the theory we consider can explain the non-zero reported variation in the evolution of α by purely considering disformal couplings. We also find that if matter and photons are coupled in the same way to the scalar field, disformal couplings itself do not lead to a variation of the fine-structure constant. A number of scenarios are discussed consistent with the current astrophysical, geochemical, laboratory and the cosmic microwave background radiation constraints on the cosmological evolution of α. The models presented are also consistent with the current type Ia supernovae constraints on the effective dark energy equation of state. We find that the Oklo bound in particular puts strong constraints on the model parameters. From our numerical results, we find that the introduction of a non-minimal electromagnetic coupling enhances the cosmological variation in α. Better constrained data is expected to be reported by ALMA and with the forthcoming generation of high-resolution ultra-stable spectrographs such as PEPSI, ESPRESSO, and ELT-HIRES. Furthermore, an expected increase in the sensitivity of molecular and nuclear clocks will put a more stringent constraint on the theory

Variational integrators for reduced magnetohydrodynamics

Energy Technology Data Exchange (ETDEWEB)

Kraus, Michael, E-mail: michael.kraus@ipp.mpg.de [Max-Planck-Institut für Plasmaphysik, Boltzmannstraße 2, 85748 Garching (Germany); Technische Universität München, Zentrum Mathematik, Boltzmannstraße 3, 85748 Garching (Germany); Tassi, Emanuele, E-mail: tassi@cpt.univ-mrs.fr [Aix-Marseille Université, Université de Toulon, CNRS, CPT, UMR 7332, 163 avenue de Luminy, case 907, 13288 cedex 9 Marseille (France); Grasso, Daniela, E-mail: daniela.grasso@infm.polito.it [ISC-CNR and Politecnico di Torino, Dipartimento Energia, C.so Duca degli Abruzzi 24, 10129 Torino (Italy)

2016-09-15

Reduced magnetohydrodynamics is a simplified set of magnetohydrodynamics equations with applications to both fusion and astrophysical plasmas, possessing a noncanonical Hamiltonian structure and consequently a number of conserved functionals. We propose a new discretisation strategy for these equations based on a discrete variational principle applied to a formal Lagrangian. The resulting integrator preserves important quantities like the total energy, magnetic helicity and cross helicity exactly (up to machine precision). As the integrator is free of numerical resistivity, spurious reconnection along current sheets is absent in the ideal case. If effects of electron inertia are added, reconnection of magnetic field lines is allowed, although the resulting model still possesses a noncanonical Hamiltonian structure. After reviewing the conservation laws of the model equations, the adopted variational principle with the related conservation laws is described both at the continuous and discrete level. We verify the favourable properties of the variational integrator in particular with respect to the preservation of the invariants of the models under consideration and compare with results from the literature and those of a pseudo-spectral code.

Variational cellular model of the molecular and crystal electronic structure

International Nuclear Information System (INIS)

Ferreira, L.G.; Leite, J.R.

1977-12-01

A variational version of the cellular method is developed to calculate the electronic structure of molecules and crystals. Due to the simplicity of the secular equation, the method is easy to be implemented. Preliminary calculations on the hydrogen molecular ion suggest that it is also accurate and of fast convergence [pt

Adaptations to the coping power program's structure, delivery settings, and clinician training.

Science.gov (United States)

Lochman, John E; Powell, Nicole; Boxmeyer, Caroline; Andrade, Brendan; Stromeyer, Sara L; Jimenez-Camargo, Luis Alberto

2012-06-01

This article describes the conceptual framework for the Coping Power program that has focused on proximal risk factors that can actively alter preadolescent children's aggressive behavior. The results of initial controlled efficacy trials are summarized. However, consistent with the theme of this special section, some clinicians and workshop participants have indicated barriers to the implementation of the Coping Power program in their service settings. In response to these types of concerns, three key areas of programmatic adaptation of the program that serve to address these concerns are then described in the article. First, existing and in-process studies of variations in how the program can be delivered are presented. Existing findings indicate how the child component fares when delivered by itself without the parent component, how simple monthly boosters affect intervention effects, and whether the program can be reduced by a third of its length and still be effective. Research planned or in progress on program variations examines whether group versus individual delivery of the program affects outcomes, whether the program can be adapted for early adolescents, whether the program can be delivered in an adaptive manner with the use of the Family Check Up, and whether a brief, efficient version of the program in conjunction with Internet programming can be developed and be effective. Second, the program has been and is being developed for use in different settings, other than the school-based delivery in the efficacy trials. Research has examined its use with aggressive deaf youth in a residential setting, with Oppositional Defiant Disorder and Conduct Disorder children in outpatient clinics, and in after-school programs. Third, the article reports how variations in training clinicians affect their ability to effectively use the program. PsycINFO Database Record (c) 2012 APA, all rights reserved.

Microsatellite diversity and broad scale geographic structure in a model legume: building a set of nested core collection for studying naturally occurring variation in Medicago truncatula

DEFF Research Database (Denmark)

Ronfort, Joelle; Bataillon, Thomas; Santoni, Sylvain

2006-01-01

at representing the genetic diversity of this species with a minimum of repetitiveness. We investigate the patterns of genetic diversity and population structure in a collection of 346 inbred lines representing the breadth of naturally occurring diversity in the Legume plant model Medicago truncatula using 13...... of inbred lines and the core collections are publicly available and will help coordinating efforts for the study of naturally occurring variation in the growing Medicago truncatula community....

Cosmological constraints on variations of the fine structure constant at the epoch of recombination

International Nuclear Information System (INIS)

Menegoni, E; Galli, S; Archidiacono, M; Calabrese, E; Melchiorri, A

2013-01-01

In this brief work we investigate any possible variation of the fine structure constant at the epoch of recombination. The recent measurements of the Cosmic Microwave Background anisotropies at arcminute angular scales performed by the ACT and SPT experiments are probing the damping regime of Cosmic Microwave Background fluctuations. We study the role of a mechanism that could affect the shape of the Cosmic Microwave Background angular fluctuations at those scales, namely a change in the recombination process through variations in the fine structure constant α

Validation of the Amsterdam Dynamic Facial Expression Set – Bath Intensity Variations (ADFES-BIV): A Set of Videos Expressing Low, Intermediate, and High Intensity Emotions

Science.gov (United States)

Wingenbach, Tanja S. H.

2016-01-01

Most of the existing sets of facial expressions of emotion contain static photographs. While increasing demand for stimuli with enhanced ecological validity in facial emotion recognition research has led to the development of video stimuli, these typically involve full-blown (apex) expressions. However, variations of intensity in emotional facial expressions occur in real life social interactions, with low intensity expressions of emotions frequently occurring. The current study therefore developed and validated a set of video stimuli portraying three levels of intensity of emotional expressions, from low to high intensity. The videos were adapted from the Amsterdam Dynamic Facial Expression Set (ADFES) and termed the Bath Intensity Variations (ADFES-BIV). A healthy sample of 92 people recruited from the University of Bath community (41 male, 51 female) completed a facial emotion recognition task including expressions of 6 basic emotions (anger, happiness, disgust, fear, surprise, sadness) and 3 complex emotions (contempt, embarrassment, pride) that were expressed at three different intensities of expression and neutral. Accuracy scores (raw and unbiased (Hu) hit rates) were calculated, as well as response times. Accuracy rates above chance level of responding were found for all emotion categories, producing an overall raw hit rate of 69% for the ADFES-BIV. The three intensity levels were validated as distinct categories, with higher accuracies and faster responses to high intensity expressions than intermediate intensity expressions, which had higher accuracies and faster responses than low intensity expressions. To further validate the intensities, a second study with standardised display times was conducted replicating this pattern. The ADFES-BIV has greater ecological validity than many other emotion stimulus sets and allows for versatile applications in emotion research. It can be retrieved free of charge for research purposes from the corresponding author

Variational discretization of the nonequilibrium thermodynamics of simple systems

Science.gov (United States)

Gay-Balmaz, François; Yoshimura, Hiroaki

2018-04-01

In this paper, we develop variational integrators for the nonequilibrium thermodynamics of simple closed systems. These integrators are obtained by a discretization of the Lagrangian variational formulation of nonequilibrium thermodynamics developed in (Gay-Balmaz and Yoshimura 2017a J. Geom. Phys. part I 111 169–93 Gay-Balmaz and Yoshimura 2017b J. Geom. Phys. part II 111 194–212) and thus extend the variational integrators of Lagrangian mechanics, to include irreversible processes. In the continuous setting, we derive the structure preserving property of the flow of such systems. This property is an extension of the symplectic property of the flow of the Euler–Lagrange equations. In the discrete setting, we show that the discrete flow solution of our numerical scheme verifies a discrete version of this property. We also present the regularity conditions which ensure the existence of the discrete flow. We finally illustrate our discrete variational schemes with the implementation of an example of a simple and closed system.

Fast magnetic resonance imaging based on high degree total variation

Science.gov (United States)

Wang, Sujie; Lu, Liangliang; Zheng, Junbao; Jiang, Mingfeng

2018-04-01

In order to eliminating the artifacts and "staircase effect" of total variation in Compressive Sensing MRI, high degree total variation model is proposed for dynamic MRI reconstruction. the high degree total variation regularization term is used as a constraint to reconstruct the magnetic resonance image, and the iterative weighted MM algorithm is proposed to solve the convex optimization problem of the reconstructed MR image model, In addtion, one set of cardiac magnetic resonance data is used to verify the proposed algorithm for MRI. The results show that the high degree total variation method has a better reconstruction effect than the total variation and the total generalized variation, which can obtain higher reconstruction SNR and better structural similarity.

VARIATIONAL PRINCIPLE FOR PLANETARY INTERIORS

International Nuclear Information System (INIS)

Zeng, Li; Jacobsen, Stein B.

2016-01-01

In the past few years, the number of confirmed planets has grown above 2000. It is clear that they represent a diversity of structures not seen in our own solar system. In addition to very detailed interior modeling, it is valuable to have a simple analytical framework for describing planetary structures. The variational principle is a fundamental principle in physics, entailing that a physical system follows the trajectory, which minimizes its action. It is alternative to the differential equation formulation of a physical system. Applying the variational principle to the planetary interior can beautifully summarize the set of differential equations into one, which provides us some insight into the problem. From this principle, a universal mass–radius relation, an estimate of the error propagation from the equation of state to the mass–radius relation, and a form of the virial theorem applicable to planetary interiors are derived.

Pre-set extrusion bioprinting for multiscale heterogeneous tissue structure fabrication.

Science.gov (United States)

Kang, Donggu; Ahn, Geunseon; Kim, Donghwan; Kang, Hyun-Wook; Yun, Seokhwan; Yun, Won-Soo; Shim, Jin-Hyung; Jin, Songwan

2018-06-06

Recent advances in three-dimensional bioprinting technology have led to various attempts in fabricating human tissue-like structures. However, current bioprinting technologies have limitations for creating native tissue-like structures. To resolve these issues, we developed a new pre-set extrusion bioprinting technique that can create heterogeneous, multicellular, and multimaterial structures simultaneously. The key to this ability lies in the use of a precursor cartridge that can stably preserve a multimaterial with a pre-defined configuration that can be simply embedded in a syringe-based printer head. The multimaterial can be printed and miniaturized through a micro-nozzle without conspicuous deformation according to the pre-defined configuration of the precursor cartridge. Using this system, we fabricated heterogeneous tissue-like structures such as spinal cords, hepatic lobule, blood vessels, and capillaries. We further obtained a heterogeneous patterned model that embeds HepG2 cells with endothelial cells in a hepatic lobule-like structure. In comparison with homogeneous and heterogeneous cell printing, the heterogeneous patterned model showed a well-organized hepatic lobule structure and higher enzyme activity of CYP3A4. Therefore, this pre-set extrusion bioprinting method could be widely used in the fabrication of a variety of artificial and functional tissues or organs.

Topological structure of the solution set for evolution inclusions

CERN Document Server

Zhou, Yong; Peng, Li

2017-01-01

This book systematically presents the topological structure of solution sets and attractability for nonlinear evolution inclusions, together with its relevant applications in control problems and partial differential equations. It provides readers the background material needed to delve deeper into the subject and explore the rich research literature.  In addition, the book addresses many of the basic techniques and results recently developed in connection with this theory, including the structure of solution sets for evolution inclusions with m-dissipative operators; quasi-autonomous and non-autonomous evolution inclusions and control systems;evolution inclusions with the Hille-Yosida operator; functional evolution inclusions; impulsive evolution inclusions; and stochastic evolution inclusions. Several applications of evolution inclusions and control systems are also discussed in detail.  Based on extensive research work conducted by the authors and other experts over the past four years, the information p...

Optimal structural inference of signaling pathways from unordered and overlapping gene sets.

Science.gov (United States)

Acharya, Lipi R; Judeh, Thair; Wang, Guangdi; Zhu, Dongxiao

2012-02-15

A plethora of bioinformatics analysis has led to the discovery of numerous gene sets, which can be interpreted as discrete measurements emitted from latent signaling pathways. Their potential to infer signaling pathway structures, however, has not been sufficiently exploited. Existing methods accommodating discrete data do not explicitly consider signal cascading mechanisms that characterize a signaling pathway. Novel computational methods are thus needed to fully utilize gene sets and broaden the scope from focusing only on pairwise interactions to the more general cascading events in the inference of signaling pathway structures. We propose a gene set based simulated annealing (SA) algorithm for the reconstruction of signaling pathway structures. A signaling pathway structure is a directed graph containing up to a few hundred nodes and many overlapping signal cascades, where each cascade represents a chain of molecular interactions from the cell surface to the nucleus. Gene sets in our context refer to discrete sets of genes participating in signal cascades, the basic building blocks of a signaling pathway, with no prior information about gene orderings in the cascades. From a compendium of gene sets related to a pathway, SA aims to search for signal cascades that characterize the optimal signaling pathway structure. In the search process, the extent of overlap among signal cascades is used to measure the optimality of a structure. Throughout, we treat gene sets as random samples from a first-order Markov chain model. We evaluated the performance of SA in three case studies. In the first study conducted on 83 KEGG pathways, SA demonstrated a significantly better performance than Bayesian network methods. Since both SA and Bayesian network methods accommodate discrete data, use a 'search and score' network learning strategy and output a directed network, they can be compared in terms of performance and computational time. In the second study, we compared SA and

Annual Variation and Global Structures of The DE3 Tide

International Nuclear Information System (INIS)

Ze-Yu, Chen; Da-Ren, Lu

2008-01-01

The SABER/TIMED temperatures taken in 2002–2006 are used to delineate the tidal signals in the middle and upper atmosphere. Then the Hough mode decomposition is applied with the DE3 tide, and the overall features of the seasonal variations and the complete global structures of the tide are observed. Investigation results show that the tide is most prominent at 110 km with the maximal amplitude of > 9K, and exhibits significant seasonal variation with its maximum amplitude always occurring in July every year. Results from the Hough mode decomposition reveal that the tide is composed primarily of two leading propagating Hough modes, i.e., the (−3,3) and the (−3,4) modes, thus is equatorially trapped. Estimation of the mean amplitude of the Hough modes show that the (−3,3) mode and (−3,4) mode exhibit maxima at 110km and 90 km, respectively. The (−3,3) mode plays a predominant role in shaping the global latitude-height structure of the tide, e.g., the vertical scale of > 50km at the equator, and the annual course. Significant influence of the (−3,4) mode is found below 90km, where the tide exhibits anti-symmetric structure about the equator; meanwhile the tide at northern tropical latitudes exhibits smaller vertical wavelength of about 30 km. (geophysics, astronomy, and astrophysics)

Composite Elements for Biomimetic Aerospace Structures with Progressive Shape Variation Capabilities

Directory of Open Access Journals (Sweden)

Alessandro Airoldi

2016-07-01

Full Text Available The paper presents some engineering solutions for the development of innovative aerodynamic surfaces with the capability of progressive shape variation. A brief introduction of the most significant issues related to the design of such morphing structures is provided. Thereafter, two types of structural solutions are presented for the design of internal compliant structures and flexible external skins. The proposed solutions exploit the properties and the manufacturing techniques of long fibre reinforced plastic in order to fulfil the severe and contradictory requirements related to the trade-off between morphing performance and load carrying capabilities.

Knowledge and theme discovery across very large biological data sets using distributed queries: a prototype combining unstructured and structured data.

Directory of Open Access Journals (Sweden)

Uma S Mudunuri

Full Text Available As the discipline of biomedical science continues to apply new technologies capable of producing unprecedented volumes of noisy and complex biological data, it has become evident that available methods for deriving meaningful information from such data are simply not keeping pace. In order to achieve useful results, researchers require methods that consolidate, store and query combinations of structured and unstructured data sets efficiently and effectively. As we move towards personalized medicine, the need to combine unstructured data, such as medical literature, with large amounts of highly structured and high-throughput data such as human variation or expression data from very large cohorts, is especially urgent. For our study, we investigated a likely biomedical query using the Hadoop framework. We ran queries using native MapReduce tools we developed as well as other open source and proprietary tools. Our results suggest that the available technologies within the Big Data domain can reduce the time and effort needed to utilize and apply distributed queries over large datasets in practical clinical applications in the life sciences domain. The methodologies and technologies discussed in this paper set the stage for a more detailed evaluation that investigates how various data structures and data models are best mapped to the proper computational framework.

Precise colocalization of interacting structural and pigmentary elements generates extensive color pattern variation in Phelsuma lizards

Science.gov (United States)

2013-01-01

Background Color traits in animals play crucial roles in thermoregulation, photoprotection, camouflage, and visual communication, and are amenable to objective quantification and modeling. However, the extensive variation in non-melanic pigments and structural colors in squamate reptiles has been largely disregarded. Here, we used an integrated approach to investigate the morphological basis and physical mechanisms generating variation in color traits in tropical day geckos of the genus Phelsuma. Results Combining histology, optics, mass spectrometry, and UV and Raman spectroscopy, we found that the extensive variation in color patterns within and among Phelsuma species is generated by complex interactions between, on the one hand, chromatophores containing yellow/red pteridine pigments and, on the other hand, iridophores producing structural color by constructive interference of light with guanine nanocrystals. More specifically, we show that 1) the hue of the vivid dorsolateral skin is modulated both by variation in geometry of structural, highly ordered narrowband reflectors, and by the presence of yellow pigments, and 2) that the reflectivity of the white belly and of dorsolateral pigmentary red marks, is increased by underlying structural disorganized broadband reflectors. Most importantly, these interactions require precise colocalization of yellow and red chromatophores with different types of iridophores, characterized by ordered and disordered nanocrystals, respectively. We validated these results through numerical simulations combining pigmentary components with a multilayer interferential optical model. Finally, we show that melanophores form dark lateral patterns but do not significantly contribute to variation in blue/green or red coloration, and that changes in the pH or redox state of pigments provide yet another source of color variation in squamates. Conclusions Precisely colocalized interacting pigmentary and structural elements generate extensive

Structural equations in language learning

NARCIS (Netherlands)

Moortgat, M.J.

In categorial systems with a fixed structural component, the learning problem comes down to finding the solution for a set of typeassignment equations. A hard-wired structural component is problematic if one want to address issues of structural variation. Our starting point is a type-logical

A Modified Alternating Direction Method for Variational Inequality Problems

International Nuclear Information System (INIS)

Han, D.

2002-01-01

The alternating direction method is an attractive method for solving large-scale variational inequality problems whenever the subproblems can be solved efficiently. However, the subproblems are still variational inequality problems, which are as structurally difficult to solve as the original one. To overcome this disadvantage, in this paper we propose a new alternating direction method for solving a class of nonlinear monotone variational inequality problems. In each iteration the method just makes an orthogonal projection to a simple set and some function evaluations. We report some preliminary computational results to illustrate the efficiency of the method

A variational image-based approach to the correction of susceptibility artifacts in the alignment of diffusion weighted and structural MRI.

Science.gov (United States)

Tao, Ran; Fletcher, P Thomas; Gerber, Samuel; Whitaker, Ross T

2009-01-01

This paper presents a method for correcting the geometric and greyscale distortions in diffusion-weighted MRI that result from inhomogeneities in the static magnetic field. These inhomogeneities may due to imperfections in the magnet or to spatial variations in the magnetic susceptibility of the object being imaged--so called susceptibility artifacts. Echo-planar imaging (EPI), used in virtually all diffusion weighted acquisition protocols, assumes a homogeneous static field, which generally does not hold for head MRI. The resulting distortions are significant, sometimes more than ten millimeters. These artifacts impede accurate alignment of diffusion images with structural MRI, and are generally considered an obstacle to the joint analysis of connectivity and structure in head MRI. In principle, susceptibility artifacts can be corrected by acquiring (and applying) a field map. However, as shown in the literature and demonstrated in this paper, field map corrections of susceptibility artifacts are not entirely accurate and reliable, and thus field maps do not produce reliable alignment of EPIs with corresponding structural images. This paper presents a new, image-based method for correcting susceptibility artifacts. The method relies on a variational formulation of the match between an EPI baseline image and a corresponding T2-weighted structural image but also specifically accounts for the physics of susceptibility artifacts. We derive a set of partial differential equations associated with the optimization, describe the numerical methods for solving these equations, and present results that demonstrate the effectiveness of the proposed method compared with field-map correction.

Updated constraints on spatial variations of the fine-structure constant

Directory of Open Access Journals (Sweden)

A.M.M. Pinho

2016-05-01

Full Text Available Recent work by Webb et al. has provided indications of spatial variations of the fine-structure constant, α, at a level of a few parts per million. Using a dataset of 293 archival measurements, they further show that a dipole provides a statistically good fit to the data, a result subsequently confirmed by other authors. Here we show that a more recent dataset of dedicated measurements further constrains these variations: although there are only 10 such measurements, their uncertainties are considerably smaller. We find that a dipolar variation is still a good fit to the combined dataset, but the amplitude of such a dipole must be somewhat smaller: 8.1±1.7 ppm for the full dataset, versus 9.4±2.2 ppm for the Webb et al. data alone, both at the 68.3% confidence level. Constraints on the direction on the sky of such a dipole are also significantly improved. On the other hand the data can't yet discriminate between a pure spatial dipole and one with an additional redshift dependence.

Elastic modulus of muscle and tendon with shear wave ultrasound elastography: variations with different technical settings.

Directory of Open Access Journals (Sweden)

Brian Chin Wing Kot

Full Text Available Standardization on Shear wave ultrasound elastography (SWUE technical settings will not only ensure that the results are accurate, but also detect any differences over time that may be attributed to true physiological changes. The present study evaluated the variations of elastic modulus of muscle and tendon using SWUE when different technical aspects were altered. The results of this study indicated that variations of elastic modulus of muscle and tendon were found when different transducer's pressure and region of interest (ROI's size were applied. No significant differences in elastic modulus of the rectus femoris muscle and patellar tendon were found with different acquisition times of the SWUE sonogram. The SWUE on the muscle and tendon should be performed with the lightest transducer's pressure, a shorter acquisition time for the SWUE sonogram, while measuring the mean elastic modulus regardless the ROI's size.

Rotational stellar structures based on the Lagrangian variational principle

International Nuclear Information System (INIS)

Yasutake, Nobutoshi; Fujisawa, Kotaro; Yamada, Shoichi

2017-01-01

A new method for multi-dimensional stellar structures is proposed in this study. As for stellar evolution calculations, the Heney method is the defacto standard now, but basically assumed to be spherical symmetric. It is one of the difficulties for deformed stellar-evolution calculations to trace the potentially complex movements of each fluid element. On the other hand, our new method is very suitable to follow such movements, since it is based on the Lagrange coordinate. This scheme is also based on the variational principle, which is adopted to the studies for the pasta structures inside of neutron stars. Our scheme could be a major break through for evolution calculations of any types of deformed stars: proto-planets, proto-stars, and proto-neutron stars, etc. (paper)

Rotational stellar structures based on the Lagrangian variational principle

Science.gov (United States)

Yasutake, Nobutoshi; Fujisawa, Kotaro; Yamada, Shoichi

2017-06-01

A new method for multi-dimensional stellar structures is proposed in this study. As for stellar evolution calculations, the Heney method is the defacto standard now, but basically assumed to be spherical symmetric. It is one of the difficulties for deformed stellar-evolution calculations to trace the potentially complex movements of each fluid element. On the other hand, our new method is very suitable to follow such movements, since it is based on the Lagrange coordinate. This scheme is also based on the variational principle, which is adopted to the studies for the pasta structures inside of neutron stars. Our scheme could be a major break through for evolution calculations of any types of deformed stars: proto-planets, proto-stars, and proto-neutron stars, etc.

Variation and Genetic Structure in Platanus mexicana (Platanaceae along Riparian Altitudinal Gradient

Directory of Open Access Journals (Sweden)

Dulce M. Galván-Hernández

2015-01-01

Full Text Available Platanus mexicana is a dominant arboreal species of riparian ecosystems. These ecosystems are associated with altitudinal gradients that can generate genetic differences in the species, especially in the extremes of the distribution. However, studies on the altitudinal effect on genetic variation to riparian species are scarce. In Mexico, the population of P. mexicana along the Colipa River (Veracruz State grows below its reported minimum altitude range, possibly the lowest where this tree grows. This suggests that altitude might be an important factor in population genetics differentiation. We examined the genetic variation and population structuring at four sites with different altitudes (70, 200, 600 and 1700 m a.s.l. using ten inter-simple sequence repeats (ISSR markers. The highest value for Shannon index and Nei’s gene diversity was obtained at 1700 m a.s.l. (He = 0.27, Ne = 1.47, I = 0.42 and polymorphism reached the top value at the middle altitude (% p = 88.57. Analysis of molecular variance (AMOVA and STRUCTURE analysis indicated intrapopulation genetic differentiation. The arithmetic average (UPGMA dendrogram identified 70 m a.s.l. as the most genetically distant site. The genetic structuring resulted from limited gene flow and genetic drift. This is the first report of genetic variation in populations of P. mexicana in Mexico. This research highlights its importance as a dominant species, and its ecological and evolutionary implications in altitudinal gradients of riparian ecosystems.

Variational principles for locally variational forms

International Nuclear Information System (INIS)

Brajercik, J.; Krupka, D.

2005-01-01

We present the theory of higher order local variational principles in fibered manifolds, in which the fundamental global concept is a locally variational dynamical form. Any two Lepage forms, defining a local variational principle for this form, differ on intersection of their domains, by a variationally trivial form. In this sense, but in a different geometric setting, the local variational principles satisfy analogous properties as the variational functionals of the Chern-Simons type. The resulting theory of extremals and symmetries extends the first order theories of the Lagrange-Souriau form, presented by Grigore and Popp, and closed equivalents of the first order Euler-Lagrange forms of Hakova and Krupkova. Conceptually, our approach differs from Prieto, who uses the Poincare-Cartan forms, which do not have higher order global analogues

Genetic structure, diversity, and allelic richness in composite collection and reference set in chickpea (Cicer arietinum L.

Directory of Open Access Journals (Sweden)

Gowda Cholenahalli LL

2008-10-01

Full Text Available Abstract Background Plant genetic resources (PGR are the basic raw materials for future genetic progress and an insurance against unforeseen threats to agricultural production. An extensive characterization of PGR provides an opportunity to dissect structure, mine allelic variations, and identify diverse accessions for crop improvement. The Generation Challenge Program http://www.generationcp.org conceptualized the development of "composite collections" and extraction of "reference sets" from these for more efficient tapping of global crop-related genetic resources. In this study, we report the genetic structure, diversity and allelic richness in a composite collection of chickpea using SSR markers, and formation of a reference set of 300 accessions. Results The 48 SSR markers detected 1683 alleles in 2915 accessions, of which, 935 were considered rare, 720 common and 28 most frequent. The alleles per locus ranged from 14 to 67, averaged 35, and the polymorphic information content was from 0.467 to 0.974, averaged 0.854. Marker polymorphism varied between groups of accessions in the composite collection and reference set. A number of group-specific alleles were detected: 104 in Kabuli, 297 in desi, and 69 in wild Cicer; 114 each in Mediterranean and West Asia (WA, 117 in South and South East Asia (SSEA, and 10 in African region accessions. Desi and kabuli shared 436 alleles, while wild Cicer shared 17 and 16 alleles with desi and kabuli, respectively. The accessions from SSEA and WA shared 74 alleles, while those from Mediterranean 38 and 33 alleles with WA and SSEA, respectively. Desi chickpea contained a higher proportion of rare alleles (53% than kabuli (46%, while wild Cicer accessions were devoid of rare alleles. A genotype-based reference set captured 1315 (78% of the 1683 composite collection alleles of which 463 were rare, 826 common, and 26 the most frequent alleles. The neighbour-joining tree diagram of this reference set represents

Structural Studies of the SET Domain from RIZ1 Tumor Suppressor

Energy Technology Data Exchange (ETDEWEB)

Briknarova, Klara; Zhou, Xinliang; Satterthwait, Arnold C.; Hoyt, David W.; Ely, Kathryn R.; Huang, Shi

2008-02-15

Histone lysine methyltransferases (HKMTs) are involved in regulation of chromatin structure, and, as such, are important for longterm gene activation and repression that is associated with cell memory and establishment of cell-type specific transcriptional programs. Most HKMTs contain a SET domain, which is responsible for their catalytic activity. RIZ1 is a transcription regulator and tumor suppressor that catalyzes methylation of lysine 9 of histone H3 and contains a rather distinct SET domain. Similar SET domains, sometimes refererred to as PR (PRDI-BF1 and RIZ1 homology) domains, are also found in other proteins including Blimp-1/PRDI-BF1, MDS1-EVI1 and Meisetz. We determined the solution structure of the PR domain from RIZ1 and characterized its interaction with S-adenosyl homocysteine (SAH) and a peptide from histone H3. Despite low sequence identity with canonical SET domains, the PR domain displays a typical SET fold including a pseudo-knot at the C-terminus. The N-flanking sequence of RIZ1 PR domain adopts a novel conformation and interacts closely with the SET fold. The C-flanking sequence contains an α-helix that exhibits higher mobility than the SET fold and points away from the protein face that harbors active site in other SET domains. Residues that interact with the methylation cofactor in SET domains are not conserved in RIZ1 or other PR domains, and the SET fold of RIZ1 does not bind SAH. However, the PR domain of RIZ1 interacts specifically with a synthetic peptide comprising residues 1-20 of histone H3.

Analyzing structural variations along strike in a deep-water thrust belt

Science.gov (United States)

Totake, Yukitsugu; Butler, Robert W. H.; Bond, Clare E.; Aziz, Aznan

2018-03-01

We characterize a deep-water fold-thrust arrays imaged by a high-resolution 3D seismic dataset in the offshore NW Borneo, Malaysia, to understand the kinematics behind spatial arrangement of structural variations throughout the fold-thrust system. The seismic volume used covers two sub-parallel fold trains associated with a series of fore-thrusts and back-thrusts. We measured fault heave, shortening value, fold geometries (forelimb dip, interlimb angle and crest depth) along strike in individual fold trains. Heave plot on strike projection allows to identify individual thrust segments showing semi-elliptical to triangular to bimodal patterns, and linkages of these segments. The linkage sites are marked by local minima in cumulative heave. These local heave minima are compensated by additional structures, such as small imbricate thrusts and tight folds indicated by large forelimb dip and small interlimb angle. Complementary profiles of the shortening amount for the two fold trains result in smoother gradient of total shortening across the structures. We interpret this reflects kinematic interaction between two fold-thrust trains. This type of along-strike variation analysis provides comprehensive understanding of a fold-thrust system and may provide an interpretative strategy for inferring the presence of complex multiple faults in less well-imaged parts of seismic volumes.

Stochastic level-set variational implicit-solvent approach to solute-solvent interfacial fluctuations

Energy Technology Data Exchange (ETDEWEB)

Zhou, Shenggao, E-mail: sgzhou@suda.edu.cn, E-mail: bli@math.ucsd.edu [Department of Mathematics and Mathematical Center for Interdiscipline Research, Soochow University, 1 Shizi Street, Jiangsu, Suzhou 215006 (China); Sun, Hui; Cheng, Li-Tien [Department of Mathematics, University of California, San Diego, La Jolla, California 92093-0112 (United States); Dzubiella, Joachim [Soft Matter and Functional Materials, Helmholtz-Zentrum Berlin, 14109 Berlin, Germany and Institut für Physik, Humboldt-Universität zu Berlin, 12489 Berlin (Germany); Li, Bo, E-mail: sgzhou@suda.edu.cn, E-mail: bli@math.ucsd.edu [Department of Mathematics and Quantitative Biology Graduate Program, University of California, San Diego, La Jolla, California 92093-0112 (United States); McCammon, J. Andrew [Department of Chemistry and Biochemistry, Department of Pharmacology, Howard Hughes Medical Institute, University of California, San Diego, La Jolla, California 92093-0365 (United States)

2016-08-07

Recent years have seen the initial success of a variational implicit-solvent model (VISM), implemented with a robust level-set method, in capturing efficiently different hydration states and providing quantitatively good estimation of solvation free energies of biomolecules. The level-set minimization of the VISM solvation free-energy functional of all possible solute-solvent interfaces or dielectric boundaries predicts an equilibrium biomolecular conformation that is often close to an initial guess. In this work, we develop a theory in the form of Langevin geometrical flow to incorporate solute-solvent interfacial fluctuations into the VISM. Such fluctuations are crucial to biomolecular conformational changes and binding process. We also develop a stochastic level-set method to numerically implement such a theory. We describe the interfacial fluctuation through the “normal velocity” that is the solute-solvent interfacial force, derive the corresponding stochastic level-set equation in the sense of Stratonovich so that the surface representation is independent of the choice of implicit function, and develop numerical techniques for solving such an equation and processing the numerical data. We apply our computational method to study the dewetting transition in the system of two hydrophobic plates and a hydrophobic cavity of a synthetic host molecule cucurbit[7]uril. Numerical simulations demonstrate that our approach can describe an underlying system jumping out of a local minimum of the free-energy functional and can capture dewetting transitions of hydrophobic systems. In the case of two hydrophobic plates, we find that the wavelength of interfacial fluctuations has a strong influence to the dewetting transition. In addition, we find that the estimated energy barrier of the dewetting transition scales quadratically with the inter-plate distance, agreeing well with existing studies of molecular dynamics simulations. Our work is a first step toward the

CNNdel: Calling Structural Variations on Low Coverage Data Based on Convolutional Neural Networks

Directory of Open Access Journals (Sweden)

Jing Wang

2017-01-01

Full Text Available Many structural variations (SVs detection methods have been proposed due to the popularization of next-generation sequencing (NGS. These SV calling methods use different SV-property-dependent features; however, they all suffer from poor accuracy when running on low coverage sequences. The union of results from these tools achieves fairly high sensitivity but still produces low accuracy on low coverage sequence data. That is, these methods contain many false positives. In this paper, we present CNNdel, an approach for calling deletions from paired-end reads. CNNdel gathers SV candidates reported by multiple tools and then extracts features from aligned BAM files at the positions of candidates. With labeled feature-expressed candidates as a training set, CNNdel trains convolutional neural networks (CNNs to distinguish true unlabeled candidates from false ones. Results show that CNNdel works well with NGS reads from 26 low coverage genomes of the 1000 Genomes Project. The paper demonstrates that convolutional neural networks can automatically assign the priority of SV features and reduce the false positives efficaciously.

Geminal embedding scheme for optimal atomic basis set construction in correlated calculations

Energy Technology Data Exchange (ETDEWEB)

Sorella, S., E-mail: sorella@sissa.it [International School for Advanced Studies (SISSA), Via Beirut 2-4, 34014 Trieste, Italy and INFM Democritos National Simulation Center, Trieste (Italy); Devaux, N.; Dagrada, M., E-mail: mario.dagrada@impmc.upmc.fr [Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie, Université Pierre et Marie Curie, Case 115, 4 Place Jussieu, 75252 Paris Cedex 05 (France); Mazzola, G., E-mail: gmazzola@phys.ethz.ch [Theoretische Physik, ETH Zurich, 8093 Zurich (Switzerland); Casula, M., E-mail: michele.casula@impmc.upmc.fr [CNRS and Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie, Université Pierre et Marie Curie, Case 115, 4 Place Jussieu, 75252 Paris Cedex 05 (France)

2015-12-28

We introduce an efficient method to construct optimal and system adaptive basis sets for use in electronic structure and quantum Monte Carlo calculations. The method is based on an embedding scheme in which a reference atom is singled out from its environment, while the entire system (atom and environment) is described by a Slater determinant or its antisymmetrized geminal power (AGP) extension. The embedding procedure described here allows for the systematic and consistent contraction of the primitive basis set into geminal embedded orbitals (GEOs), with a dramatic reduction of the number of variational parameters necessary to represent the many-body wave function, for a chosen target accuracy. Within the variational Monte Carlo method, the Slater or AGP part is determined by a variational minimization of the energy of the whole system in presence of a flexible and accurate Jastrow factor, representing most of the dynamical electronic correlation. The resulting GEO basis set opens the way for a fully controlled optimization of many-body wave functions in electronic structure calculation of bulk materials, namely, containing a large number of electrons and atoms. We present applications on the water molecule, the volume collapse transition in cerium, and the high-pressure liquid hydrogen.

Spatial Evolution of the Thickness Variations over a CFRP Laminated Structure

Science.gov (United States)

Davila, Yves; Crouzeix, Laurent; Douchin, Bernard; Collombet, Francis; Grunevald, Yves-Henri

2017-10-01

Ply thickness is one of the main drivers of the structural performance of a composite part. For stress analysis calculations (e.g., finite element analysis), composite plies are commonly considered to have a constant thickness compared to the reality (coefficients of variation up to 9% of the mean ply thickness). Unless this variability is taken into account reliable property predictions cannot be made. A modelling approach of such variations is proposed using parameters obtained from a 16-ply quasi-isotropic CFRP plate cured in an autoclave. A discrete Fourier transform algorithm is used to analyse the frequency response of the observed ply and plate thickness profiles. The model inputs, obtained by a mathematical representation of the ply thickness profiles, permit the generation of a representative stratification considering the spatial continuity of the thickness variations that are in good agreement with the real ply profiles spread over the composite part. A residual deformation FE model of the composite plate is used to illustrate the feasibility of the approach.

Mapping topographic structure in white matter pathways with level set trees.

Directory of Open Access Journals (Sweden)

Brian P Kent

Full Text Available Fiber tractography on diffusion imaging data offers rich potential for describing white matter pathways in the human brain, but characterizing the spatial organization in these large and complex data sets remains a challenge. We show that level set trees--which provide a concise representation of the hierarchical mode structure of probability density functions--offer a statistically-principled framework for visualizing and analyzing topography in fiber streamlines. Using diffusion spectrum imaging data collected on neurologically healthy controls (N = 30, we mapped white matter pathways from the cortex into the striatum using a deterministic tractography algorithm that estimates fiber bundles as dimensionless streamlines. Level set trees were used for interactive exploration of patterns in the endpoint distributions of the mapped fiber pathways and an efficient segmentation of the pathways that had empirical accuracy comparable to standard nonparametric clustering techniques. We show that level set trees can also be generalized to model pseudo-density functions in order to analyze a broader array of data types, including entire fiber streamlines. Finally, resampling methods show the reliability of the level set tree as a descriptive measure of topographic structure, illustrating its potential as a statistical descriptor in brain imaging analysis. These results highlight the broad applicability of level set trees for visualizing and analyzing high-dimensional data like fiber tractography output.

Variation Principles and Applications in the Study of Cell Structure and Aging

Science.gov (United States)

Economos, Angelos C.; Miquel, Jaime; Ballard, Ralph C.; Johnson, John E., Jr.

1981-01-01

In this report we have attempted to show that "some reality lies concealed in biological variation". This "reality" has its principles, laws, mechanisms, and rules, only a few of which we have sketched. A related idea we pursued was that important information may be lost in the process of ignoring frequency distributions of physiological variables (as is customary in experimental physiology and gerontology). We suggested that it may be advantageous to expand one's "statistical field of vision" beyond simple averages +/- standard deviations. Indeed, frequency distribution analysis may make visible some hidden information not evident from a simple qualitative analysis, particularly when the effect of some external factor or condition (e.g., aging, dietary chemicals) is being investigated. This was clearly illustrated by the application of distribution analysis in the study of variation in mouse liver cellular and fine structure, and may be true of fine structural studies in general. In living systems, structure and function interact in a dynamic way; they are "inseparable," unlike in technological systems or machines. Changes in fine structure therefore reflect changes in function. If such changes do not exceed a certain physiologic range, a quantitative analysis of structure will provide valuable information on quantitative changes in function that may not be possible or easy to measure directly. Because there is a large inherent variation in fine structure of cells in a given organ of an individual and among individuals, changes in fine structure can be analyzed only by studying frequency distribution curves of various structural characteristics (dimensions). Simple averages +/- S.D. do not in general reveal all information on the effect of a certain factor, because often this effect is not uniform; on the contrary, this will be apparent from distribution analysis because the form of the curves will be affected. We have also attempted to show in this chapter that

Tools to analyse and display variations in anatomical delineation

International Nuclear Information System (INIS)

Ebert, Martin A.; McDermott, L.N.; Haworth, A; Van der Wath, E.; Hooton, B.

2012-01-01

Variations in anatomical delineation, principally due to a combination of inter-observer contributions and image-specificity, remain one of the most significant impediments to geometrically-accurate radiotherapy. Quantification of spatial variability of the delineated contours comprising a structure can be made with a variety of metrics, and the availability of software tools to apply such metrics to data collected during inter-observer or repeat-imaging studies would allow their validation. A suite of such tools have been developed which use an Extensible Markup Language format for the exchange of delineated 3D structures with radiotherapy planning or review systems. These tools provide basic operations for manipulating and operating on individual structures and related structure sets, and for deriving statistics on spatial variations of contours that can be mapped onto the surface of a reference structure. Use of these tools on a sample dataset is demonstrated together with import and display of results in the SWAN treatment plan review system.

Self-consistent field variational cellular method as applied to the band structure calculation of sodium

International Nuclear Information System (INIS)

Lino, A.T.; Takahashi, E.K.; Leite, J.R.; Ferraz, A.C.

1988-01-01

The band structure of metallic sodium is calculated, using for the first time the self-consistent field variational cellular method. In order to implement the self-consistency in the variational cellular theory, the crystal electronic charge density was calculated within the muffin-tin approximation. The comparison between our results and those derived from other calculations leads to the conclusion that the proposed self-consistent version of the variational cellular method is fast and accurate. (author) [pt

Constraining spatial variations of the fine-structure constant in symmetron models

Directory of Open Access Journals (Sweden)

A.M.M. Pinho

2017-06-01

Full Text Available We introduce a methodology to test models with spatial variations of the fine-structure constant α, based on the calculation of the angular power spectrum of these measurements. This methodology enables comparisons of observations and theoretical models through their predictions on the statistics of the α variation. Here we apply it to the case of symmetron models. We find no indications of deviations from the standard behavior, with current data providing an upper limit to the strength of the symmetron coupling to gravity (log⁡β2<−0.9 when this is the only free parameter, and not able to constrain the model when also the symmetry breaking scale factor aSSB is free to vary.

Variation in xylem structure from tropics to tundra: Evidence from vestured pits

NARCIS (Netherlands)

Jansen, S.; Baas, P.; Gasson, P.; Lens, F.; Smets, E.

2004-01-01

Bordered pits play an important role in permitting water flow among adjacent tracheary elements in flowering plants. Variation in the bordered pit structure is suggested to be adaptive in optimally balancing the conflict between hydraulic efficiency (conductivity) and safety from air entry at the

The determination of the in situ structure by nuclear spin contrast variation

Energy Technology Data Exchange (ETDEWEB)

Stuhrmann, H.B. [GKSS Forschungszentrum, Geesthacht (Germany); Nierhaus, K.H. [Max-Planch-Institut fuer Molekulare Genetik, Berlin (Germany)

1994-12-31

Polarized neutron scattering from polarized nuclear spins in hydrogenous substances opens a new way of contrast variation. The enhanced contrast due to proton spin polarization was used for the in situ structure determination of tRNA of the functional complex of the E.coli ribosome.

The determination of the in situ structure by nuclear spin contrast variation

International Nuclear Information System (INIS)

Stuhrmann, H.B.; Nierhaus, K.H.

1994-01-01

Polarized neutron scattering from polarized nuclear spins in hydrogenous substances opens a new way of contrast variation. The enhanced contrast due to proton spin polarization was used for the in situ structure determination of tRNA of the functional complex of the E.coli ribosome

Phosphorylation Variation during the Cell Cycle Scales with Structural Propensities of Proteins

DEFF Research Database (Denmark)

Tyanova, S.; Frishman, D.; Cox, J.

2013-01-01

of the cell division cycle we investigate how the variation of the amount of phosphorylation correlates with the protein structure in the vicinity of the modified site. We find two distinct phosphorylation site groups: intrinsically disordered regions tend to contain sites with dynamically varying levels...

SV-AUTOPILOT: optimized, automated construction of structural variation discovery and benchmarking pipelines

NARCIS (Netherlands)

W.Y. Leung; T. Marschall (Tobias); Y. Paudel; L. Falquet; H. Mei (Hailiang); A. Schönhuth (Alexander); T.Y. Maoz

2015-01-01

htmlabstractBackground Many tools exist to predict structural variants (SVs), utilizing a variety of algorithms. However, they have largely been developed and tested on human germline or somatic (e.g. cancer) variation. It seems appropriate to exploit this wealth of technology available for humans

Importance of Local Structural Variations on Recrystallization

DEFF Research Database (Denmark)

Juul Jensen, Dorte; Lin, Fengxiang; Zhang, Yubin

2013-01-01

Effects of local variations in the deformation microstructure on subsequent recrystallization are discussed and illustrated by three examples. The three examples consider local variations on different length scales and are: 1. Effects of local variations in the deformation microstructure on the f...

A conformal gauge invariant functional for Weyl structures and the first variation formula

OpenAIRE

Ichiyama, Toshiyuki; Furuhata, Hitoshi; Urakawa, Hajime

1999-01-01

We consider a new conformal gauge invariant functional which is a natural curvature functional on the space of Weyl structures. We derive the first variation formula of its functional and characterize its critical points.

Validity of covariance models for the analysis of geographical variation

DEFF Research Database (Denmark)

Guillot, Gilles; Schilling, Rene L.; Porcu, Emilio

2014-01-01

1. Due to the availability of large molecular data-sets, covariance models are increasingly used to describe the structure of genetic variation as an alternative to more heavily parametrised biological models. 2. We focus here on a class of parametric covariance models that received sustained att...

Planck intermediate results. XXIV. Constraints on variation of fundamental constants

CERN Document Server

Ade, P A R; Arnaud, M.; Ashdown, M.; Aumont, J.; Baccigalupi, C.; Banday, A.J.; Barreiro, R.B.; Battaner, E.; Benabed, K.; Benoit-Levy, A.; Bernard, J.P.; Bersanelli, M.; Bielewicz, P.; Bond, J.R.; Borrill, J.; Bouchet, F.R.; Burigana, C.; Butler, R.C.; Calabrese, E.; Chamballu, A.; Chiang, H.C.; Christensen, P.R.; Clements, D.L.; Colombo, L.P.L.; Couchot, F.; Curto, A.; Cuttaia, F.; Danese, L.; Davies, R.D.; Davis, R.J.; de Bernardis, P.; de Rosa, A.; de Zotti, G.; Delabrouille, J.; Diego, J.M.; Dole, H.; Dore, O.; Dupac, X.; Ensslin, T.A.; Eriksen, H.K.; Fabre, O.; Finelli, F.; Forni, O.; Frailis, M.; Franceschi, E.; Galeotta, S.; Galli, S.; Ganga, K.; Giard, M.; Gonzalez-Nuevo, J.; Gorski, K.M.; Gregorio, A.; Gruppuso, A.; Hansen, F.K.; Hanson, D.; Harrison, D.L.; Henrot-Versille, S.; Hernandez-Monteagudo, C.; Herranz, D.; Hildebrandt, S.R.; Hivon, E.; Hobson, M.; Holmes, W.A.; Hornstrup, A.; Hovest, W.; Huffenberger, K.M.; Jaffe, A.H.; Jones, W.C.; Keihanen, E.; Keskitalo, R.; Kneissl, R.; Knoche, J.; Kunz, M.; Kurki-Suonio, H.; Lamarre, J.M.; Lasenby, A.; Lawrence, C.R.; Leonardi, R.; Lesgourgues, J.; Liguori, M.; Lilje, P.B.; Linden-Vornle, M.; Lopez-Caniego, M.; Lubin, P.M.; Macias-Perez, J.F.; Mandolesi, N.; Maris, M.; Martin, P.G.; Martinez-Gonzalez, E.; Masi, S.; Matarrese, S.; Mazzotta, P.; Meinhold, P.R.; Melchiorri, A.; Mendes, L.; Menegoni, E.; Mennella, A.; Migliaccio, M.; Miville-Deschenes, M.A.; Moneti, A.; Montier, L.; Morgante, G.; Moss, A.; Munshi, D.; Murphy, J.A.; Naselsky, P.; Nati, F.; Natoli, P.; Norgaard-Nielsen, H.U.; Noviello, F.; Novikov, D.; Novikov, I.; Oxborrow, C.A.; Pagano, L.; Pajot, F.; Paoletti, D.; Pasian, F.; Patanchon, G.; Perdereau, O.; Perotto, L.; Perrotta, F.; Piacentini, F.; Piat, M.; Pierpaoli, E.; Pietrobon, D.; Plaszczynski, S.; Pointecouteau, E.; Polenta, G.; Ponthieu, N.; Popa, L.; Pratt, G.W.; Prunet, S.; Rachen, J.P.; Rebolo, R.; Reinecke, M.; Remazeilles, M.; Renault, C.; Ricciardi, S.; Ristorcelli, I.; Rocha, G.; Roudier, G.; Rusholme, B.; Sandri, M.; Savini, G.; Scott, D.; Spencer, L.D.; Stolyarov, V.; Sudiwala, R.; Sutton, D.; Suur-Uski, A.S.; Sygnet, J.F.; Tauber, J.A.; Tavagnacco, D.; Terenzi, L.; Toffolatti, L.; Tomasi, M.; Tristram, M.; Tucci, M.; Uzan, J.P.; Valenziano, L.; Valiviita, J.; Van Tent, B.; Vielva, P.; Villa, F.; Wade, L.A.; Yvon, D.; Zacchei, A.; Zonca, A.

2015-01-01

Any variation of the fundamental physical constants, and more particularly of the fine structure constant, $\\alpha$, or of the mass of the electron, $m_e$, would affect the recombination history of the Universe and cause an imprint on the cosmic microwave background angular power spectra. We show that the Planck data allow one to improve the constraint on the time variation of the fine structure constant at redshift $z\\sim 10^3$ by about a factor of 5 compared to WMAP data, as well as to break the degeneracy with the Hubble constant, $H_0$. In addition to $\\alpha$, we can set a constraint on the variation of the mass of the electron, $m_{\\rm e}$, and on the simultaneous variation of the two constants. We examine in detail the degeneracies between fundamental constants and the cosmological parameters, in order to compare the limits obtained from Planck and WMAP and to determine the constraining power gained by including other cosmological probes. We conclude that independent time variations of the fine structu...

Novel sequence variations in LAMA2 and SGCG genes modulating cis-acting regulatory elements and RNA secondary structure

Directory of Open Access Journals (Sweden)

Olfa Siala

2010-01-01

Full Text Available In this study, we detected new sequence variations in LAMA2 and SGCG genes in 5 ethnic populations, and analysed their effect on enhancer composition and mRNA structure. PCR amplification and DNA sequencing were performed and followed by bioinformatics analyses using ESEfinder as well as MFOLD software. We found 3 novel sequence variations in the LAMA2 (c.3174+22_23insAT and c.6085 +12delA and SGCG (c.*102A/C genes. These variations were present in 210 tested healthy controls from Tunisian, Moroccan, Algerian, Lebanese and French populations suggesting that they represent novel polymorphisms within LAMA2 and SGCG genes sequences. ESEfinder showed that the c.*102A/C substitution created a new exon splicing enhancer in the 3'UTR of SGCG genes, whereas the c.6085 +12delA deletion was situated in the base pairing region between LAMA2 mRNA and the U1snRNA spliceosomal components. The RNA structure analyses showed that both variations modulated RNA secondary structure. Our results are suggestive of correlations between mRNA folding and the recruitment of spliceosomal components mediating splicing, including SR proteins. The contribution of common sequence variations to mRNA structural and functional diversity will contribute to a better study of gene expression.

A Set of Indicators to Compare Local Governance Arrangements on Homelessness

NARCIS (Netherlands)

Boesveldt, N.F.

2015-01-01

This article describes a method of comparing new governance arrangements on homelessness by studying three key features: policy, structure and management style. This is done by using a set of indicators that has been developed to measure variations in such arrangements. These indicators are based on

Simulation of fruit-set and trophic competition and optimization of yield advantages in six Capsicum cultivars using functional-structural plant modelling.

Science.gov (United States)

Ma, Y T; Wubs, A M; Mathieu, A; Heuvelink, E; Zhu, J Y; Hu, B G; Cournède, P H; de Reffye, P

2011-04-01

Many indeterminate plants can have wide fluctuations in the pattern of fruit-set and harvest. Fruit-set in these types of plants depends largely on the balance between source (assimilate supply) and sink strength (assimilate demand) within the plant. This study aims to evaluate the ability of functional-structural plant models to simulate different fruit-set patterns among Capsicum cultivars through source-sink relationships. A greenhouse experiment of six Capsicum cultivars characterized with different fruit weight and fruit-set was conducted. Fruit-set patterns and potential fruit sink strength were determined through measurement. Source and sink strength of other organs were determined via the GREENLAB model, with a description of plant organ weight and dimensions according to plant topological structure established from the measured data as inputs. Parameter optimization was determined using a generalized least squares method for the entire growth cycle. Fruit sink strength differed among cultivars. Vegetative sink strength was generally lower for large-fruited cultivars than for small-fruited ones. The larger the size of the fruit, the larger variation there was in fruit-set and fruit yield. Large-fruited cultivars need a higher source-sink ratio for fruit-set, which means higher demand for assimilates. Temporal heterogeneity of fruit-set affected both number and yield of fruit. The simulation study showed that reducing heterogeneity of fruit-set was obtained by different approaches: for example, increasing source strength; decreasing vegetative sink strength, source-sink ratio for fruit-set and flower appearance rate; and harvesting individual fruits earlier before full ripeness. Simulation results showed that, when we increased source strength or decreased vegetative sink strength, fruit-set and fruit weight increased. However, no significant differences were found between large-fruited and small-fruited groups of cultivars regarding the effects of source

Integrating population variation and protein structural analysis to improve clinical interpretation of missense variation: application to the WD40 domain.

Science.gov (United States)

Laskowski, Roman A; Tyagi, Nidhi; Johnson, Diana; Joss, Shelagh; Kinning, Esther; McWilliam, Catherine; Splitt, Miranda; Thornton, Janet M; Firth, Helen V; Wright, Caroline F

2016-03-01

We present a generic, multidisciplinary approach for improving our understanding of novel missense variants in recently discovered disease genes exhibiting genetic heterogeneity, by combining clinical and population genetics with protein structural analysis. Using six new de novo missense diagnoses in TBL1XR1 from the Deciphering Developmental Disorders study, together with population variation data, we show that the β-propeller structure of the ubiquitous WD40 domain provides a convincing way to discriminate between pathogenic and benign variation. Children with likely pathogenic mutations in this gene have severely delayed language development, often accompanied by intellectual disability, autism, dysmorphology and gastrointestinal problems. Amino acids affected by likely pathogenic missense mutations are either crucial for the stability of the fold, forming part of a highly conserved symmetrically repeating hydrogen-bonded tetrad, or located at the top face of the β-propeller, where 'hotspot' residues affect the binding of β-catenin to the TBLR1 protein. In contrast, those altered by population variation are significantly less likely to be spatially clustered towards the top face or to be at buried or highly conserved residues. This result is useful not only for interpreting benign and pathogenic missense variants in this gene, but also in other WD40 domains, many of which are associated with disease. © The Author 2016. Published by Oxford University Press.

Spatial Structure and Temporal Variation of Fish Communities in the Upper Mississippi River System

National Research Council Canada - National Science Library

Chick, John H; Ickes, Brian S; Pegg, Mark A; Barko, Valerie A; Hrabik, Robert A; Herzog, David P

2005-01-01

Variation in community composition (presence/absence data) and structure (relative abundance) of Upper Mississippi River fishes was assessed using data from the Long Term Resource Monitoring Program...

Structural system identification based on variational mode decomposition

Science.gov (United States)

Bagheri, Abdollah; Ozbulut, Osman E.; Harris, Devin K.

2018-03-01

In this paper, a new structural identification method is proposed to identify the modal properties of engineering structures based on dynamic response decomposition using the variational mode decomposition (VMD). The VMD approach is a decomposition algorithm that has been developed as a means to overcome some of the drawbacks and limitations of the empirical mode decomposition method. The VMD-based modal identification algorithm decomposes the acceleration signal into a series of distinct modal responses and their respective center frequencies, such that when combined their cumulative modal responses reproduce the original acceleration response. The decaying amplitude of the extracted modal responses is then used to identify the modal damping ratios using a linear fitting function on modal response data. Finally, after extracting modal responses from available sensors, the mode shape vector for each of the decomposed modes in the system is identified from all obtained modal response data. To demonstrate the efficiency of the algorithm, a series of numerical, laboratory, and field case studies were evaluated. The laboratory case study utilized the vibration response of a three-story shear frame, whereas the field study leveraged the ambient vibration response of a pedestrian bridge to characterize the modal properties of the structure. The modal properties of the shear frame were computed using analytical approach for a comparison with the experimental modal frequencies. Results from these case studies demonstrated that the proposed method is efficient and accurate in identifying modal data of the structures.

Exploration of Structural and Functional Variations Owing to Point Mutations in α-NAGA.

Science.gov (United States)

Meshach Paul, D; Rajasekaran, R

2018-03-01

Schindler disease is a lysosomal storage disorder caused due to deficiency or defective activity of alpha-N-acetylgalactosaminidase (α-NAGA). Mutations in gene encoding α-NAGA cause wide range of diseases, characterized with mild to severe clinical features. Molecular effects of these mutations are yet to be explored in detail. Therefore, this study was focused on four missense mutations of α-NAGA namely, S160C, E325K, R329Q and R329W. Native and mutant structures of α-NAGA were analysed to determine geometrical deviations such as the contours of root mean square deviation, root mean square fluctuation, percentage of residues in allowed regions of Ramachandran plot and solvent accessible surface area, using conformational sampling technique. Additionally, global energy-minimized structures of native and mutants were further analysed to compute their intra-molecular interactions, hydrogen bond dilution and distribution of secondary structure. In addition, docking studies were also performed to determine variations in binding energies between native and mutants. The deleterious effects of mutants were evident due to variations in their active site residues pertaining to spatial conformation and flexibility, comparatively. Hence, variations exhibited by mutants, namely S160C, E325K, R329Q and R329W to that of native, consequently, lead to the detrimental effects causing Schindler disease. This study computationally explains the underlying reasons for the pathogenesis of the disease, thereby aiding future researchers in drug development and disease management.

Variational Methods for Discontinuous Structures : Applications to Image Segmentation, Continuum Mechanics

CERN Document Server

Tomarelli, Franco

1996-01-01

In recent years many researchers in material science have focused their attention on the study of composite materials, equilibrium of crystals and crack distribution in continua subject to loads. At the same time several new issues in computer vision and image processing have been studied in depth. The understanding of many of these problems has made significant progress thanks to new methods developed in calculus of variations, geometric measure theory and partial differential equations. In particular, new technical tools have been introduced and successfully applied. For example, in order to describe the geometrical complexity of unknown patterns, a new class of problems in calculus of variations has been introduced together with a suitable functional setting: the free-discontinuity problems and the special BV and BH functions. The conference held at Villa Olmo on Lake Como in September 1994 spawned successful discussion of these topics among mathematicians, experts in computer science and material scientis...

Recurrent Somatic Structural Variations Contribute to Tumorigenesis in Pediatric Osteosarcoma

Directory of Open Access Journals (Sweden)

Xiang Chen

2014-04-01

Full Text Available Pediatric osteosarcoma is characterized by multiple somatic chromosomal lesions, including structural variations (SVs and copy number alterations (CNAs. To define the landscape of somatic mutations in pediatric osteosarcoma, we performed whole-genome sequencing of DNA from 20 osteosarcoma tumor samples and matched normal tissue in a discovery cohort, as well as 14 samples in a validation cohort. Single-nucleotide variations (SNVs exhibited a pattern of localized hypermutation called kataegis in 50% of the tumors. We identified p53 pathway lesions in all tumors in the discovery cohort, nine of which were translocations in the first intron of the TP53 gene. Beyond TP53, the RB1, ATRX, and DLG2 genes showed recurrent somatic alterations in 29%–53% of the tumors. These data highlight the power of whole-genome sequencing for identifying recurrent somatic alterations in cancer genomes that may be missed using other methods.

Polar front associated variation in prokaryotic community structure in Arctic shelf seafloor.

Science.gov (United States)

Nguyen, Tan T; Landfald, Bjarne

2015-01-01

Spatial variations in composition of marine microbial communities and its causes have largely been disclosed in studies comprising rather large environmental and spatial differences. In the present study, we explored if a moderate but temporally permanent climatic division within a contiguous arctic shelf seafloor was traceable in the diversity patterns of its bacterial and archaeal communities. Soft bottom sediment samples were collected at 10 geographical locations, spanning spatial distances of up to 640 km, transecting the oceanic polar front in the Barents Sea. The northern sampling sites were generally colder, less saline, shallower, and showed higher concentrations of freshly sedimented phytopigments compared to the southern study locations. Sampling sites depicted low variation in relative abundances of taxa at class level, with persistent numerical dominance by lineages of Gamma- and Deltaproteobacteria (57-66% of bacterial sequence reads). The Archaea, which constituted 0.7-1.8% of 16S rRNA gene copy numbers in the sediment, were overwhelmingly (85.8%) affiliated with the Thaumarchaeota. Beta-diversity analyses showed the environmental variations throughout the sampling range to have a stronger impact on the structuring of both the bacterial and archaeal communities than spatial effects. While bacterial communities were significantly influenced by the combined effect of several weakly selective environmental differences, including temperature, archaeal communities appeared to be more uniquely structured by the level of freshly sedimented phytopigments.

Lateral variation in crustal and mantle structure in Bay of Bengal based on surface wave data

Science.gov (United States)

Kumar, Amit; Mukhopadhyay, Sagarika; Kumar, Naresh; Baidya, P. R.

2018-01-01

Surface waves generated by earthquakes that occurred near Sumatra, Andaman-Nicobar Island chain and Sunda arc are used to estimate crustal and upper mantle S wave velocity structure of Bay of Bengal. Records of these seismic events at various stations located along the eastern coast of India and a few stations in the north eastern part of India are selected for such analysis. These stations lie within regional distance of the selected earthquakes. The selected events are shallow focused with magnitude greater than 5.5. Data of 65, 37, 36, 53 and 36 events recorded at Shillong, Bokaro, Visakhapatnam, Chennai and Trivandrum stations respectively are used for this purpose. The ray paths from the earthquake source to the recording stations cover different parts of the Bay of Bengal. Multiple Filtering Technique (MFT) is applied to compute the group velocities of surface waves from the available data. The dispersion curves thus obtained for this data set are within the period range of 15-120 s. Joint inversion of Rayleigh and Love wave group velocity is carried out to obtain the subsurface information in terms of variation of S wave velocity with depth. The estimated S wave velocity at a given depth and layer thickness can be considered to be an average value for the entire path covered by the corresponding ray paths. However, we observe variation in the value of S wave velocity and layer thickness from data recorded at different stations, indicating lateral variation in these two parameters. Thick deposition of sediments is observed along the paths followed by surface waves to Shillong and Bokaro stations. Sediment thickness keeps on decreasing as the surface wave paths move further south. Based on velocity variation the sedimentary layer is further divided in to three parts; on top lay unconsolidated sediment, underlain by consolidated sediment. Below this lies a layer which we consider as meta-sediments. The thickness and velocity of these layers decrease from north

Genetic Variation in Schizophrenia Liability is Shared With Intellectual Ability and Brain Structure

NARCIS (Netherlands)

Bohlken, Marc M; Brouwer, Rachel M; Mandl, René C W; Kahn, René S; Hulshoff Pol, Hilleke E

2016-01-01

BACKGROUND: Alterations in intellectual ability and brain structure are important genetic markers for schizophrenia liability. How variations in these phenotypes interact with variance in schizophrenia liability due to genetic or environmental factors is an area of active investigation. Studying

Interpopulation Variation in Contour Feather Structure Is Environmentally Determined in Great Tits

Science.gov (United States)

Broggi, Juli; Gamero, Anna; Hohtola, Esa; Orell, Markku; Nilsson, Jan-Åke

2011-01-01

Background The plumage of birds is important for flying, insulation and social communication. Contour feathers cover most of the avian body and among other functions they provide a critical insulation layer against heat loss. Feather structure and composition are known to vary among individuals, which in turn determines variation in the insulation properties of the feather. However, the extent and the proximate mechanisms underlying this variation remain unexplored. Methodology/Principal Findings We analyzed contour feather structure from two different great tit populations adapted to different winter regimes, one northern population in Oulu (Finland) and one southern population in Lund (Sweden). Great tits from the two populations differed significantly in feather structure. Birds from the northern population had a denser plumage but consisting of shorter feathers with a smaller proportion containing plumulaceous barbs, compared with conspecifics from the southern population. However, differences disappeared when birds originating from the two populations were raised and moulted in identical conditions in a common-garden experiment located in Oulu, under ad libitum nutritional conditions. All birds raised in the aviaries, including adult foster parents moulting in the same captive conditions, developed a similar feather structure. These feathers were different from that of wild birds in Oulu but similar to wild birds in Lund, the latter moulting in more benign conditions than those of Oulu. Conclusions/Significance Wild populations exposed to different conditions develop contour feather differences either due to plastic responses or constraints. Environmental conditions, such as nutrient availability during feather growth play a crucial role in determining such differences in plumage structure among populations. PMID:21949798

Interpopulation variation in contour feather structure is environmentally determined in great tits.

Directory of Open Access Journals (Sweden)

Juli Broggi

Full Text Available The plumage of birds is important for flying, insulation and social communication. Contour feathers cover most of the avian body and among other functions they provide a critical insulation layer against heat loss. Feather structure and composition are known to vary among individuals, which in turn determines variation in the insulation properties of the feather. However, the extent and the proximate mechanisms underlying this variation remain unexplored.We analyzed contour feather structure from two different great tit populations adapted to different winter regimes, one northern population in Oulu (Finland and one southern population in Lund (Sweden. Great tits from the two populations differed significantly in feather structure. Birds from the northern population had a denser plumage but consisting of shorter feathers with a smaller proportion containing plumulaceous barbs, compared with conspecifics from the southern population. However, differences disappeared when birds originating from the two populations were raised and moulted in identical conditions in a common-garden experiment located in Oulu, under ad libitum nutritional conditions. All birds raised in the aviaries, including adult foster parents moulting in the same captive conditions, developed a similar feather structure. These feathers were different from that of wild birds in Oulu but similar to wild birds in Lund, the latter moulting in more benign conditions than those of Oulu.Wild populations exposed to different conditions develop contour feather differences either due to plastic responses or constraints. Environmental conditions, such as nutrient availability during feather growth play a crucial role in determining such differences in plumage structure among populations.

Hybrid Iterative Scheme for Triple Hierarchical Variational Inequalities with Mixed Equilibrium, Variational Inclusion, and Minimization Constraints

Directory of Open Access Journals (Sweden)

Lu-Chuan Ceng

2014-01-01

Full Text Available We introduce and analyze a hybrid iterative algorithm by combining Korpelevich's extragradient method, the hybrid steepest-descent method, and the averaged mapping approach to the gradient-projection algorithm. It is proven that, under appropriate assumptions, the proposed algorithm converges strongly to a common element of the fixed point set of finitely many nonexpansive mappings, the solution set of a generalized mixed equilibrium problem (GMEP, the solution set of finitely many variational inclusions, and the solution set of a convex minimization problem (CMP, which is also a unique solution of a triple hierarchical variational inequality (THVI in a real Hilbert space. In addition, we also consider the application of the proposed algorithm to solving a hierarchical variational inequality problem with constraints of the GMEP, the CMP, and finitely many variational inclusions.

Variational Boussinesq model for simulation of coastal waves and tsunamis

NARCIS (Netherlands)

Adytia, D.; Adytia, Didit; van Groesen, Embrecht W.C.; Tan, Soon Keat; Huang, Zhenhua

2009-01-01

In this paper we describe the basic ideas of a so-called Variational Boussinesq Model which is based on the Hamiltonian structure of gravity surface waves. By using a rather simple approach to prescribe the profile of vertical fluid potential in the expression for the kinetic energy, we obtain a set

Geographically structured genetic variation in the Medicago lupulina-Ensifer mutualism.

Science.gov (United States)

Harrison, Tia L; Wood, Corlett W; Heath, Katy D; Stinchcombe, John R

2017-07-01

Gene flow between genetically differentiated populations can maintain variation in species interactions, especially when population structure is congruent between interacting species. However, large-scale empirical comparisons of the population structure of interacting species are rare, particularly in positive interspecific interactions (mutualisms). One agriculturally and ecologically important mutualism is the partnership between legume plants and rhizobia. Through characterizing and comparing the population genomic structure of the legume Medicago lupulina and two rhizobial species (Ensifer medicae and E. meliloti), we explored the spatial scale of population differentiation between interacting partners in their introduced range in North America. We found high proportions of E. meliloti in southeastern populations and high proportions of E. medicae in northwestern populations. Medicago lupulina and the Ensifer genus showed similar patterns of spatial genetic structure (isolation by distance). However, we detected no evidence of isolation by distance or population structure within either species of bacteria. Genome-wide nucleotide diversity within each of the two Ensifer species was low, suggesting limited introduction of strains, founder events, or severe bottlenecks. Our results suggest that there is potential for geographically structured coevolution between M. lupulina and the Ensifer genus, but not between M. lupulina and either Ensifer species. © 2017 The Author(s). Evolution © 2017 The Society for the Study of Evolution.

A cross-coupled-structure-based temperature sensor with reduced process variation sensitivity

Energy Technology Data Exchange (ETDEWEB)

Tie Meng; Cheng Xu, E-mail: tiemeng@mprc.pku.edu.c [Microprocessor Research and Development Center, Peking University, Beijing 100871 (China)

2009-04-15

An innovative, thermally-insensitive phenomenon of cascaded cross-coupled structures is found. And a novel CMOS temperature sensor based on a cross-coupled structure is proposed. This sensor consists of two different ring oscillators. The first ring oscillator generates pulses that have a period, changing linearly with temperature. Instead of using the system clock like in traditional sensors, the second oscillator utilizes a cascaded cross-coupled structure to generate temperature independent pulses to capture the result from the first oscillator. Due to the compensation between the two ring oscillators, errors caused by supply voltage variations and systematic process variations are reduced. The layout design of the sensor is based on the TSMC13G process standard cell library. Only three inverters are modified for proper channel width tuning without any other custom design. This allows for an easy integration of the sensor into cell-based chips. Post-layout simulations results show that an error lower than +-1.1 deg. C can be achieved in the full temperature range from -40 to 120 deg. C. As shown by SPICE simulations, the thermal insensitivity of the cross-coupled inverters can be realized for various TSMC technologies: 0.25 mum, 0.18 mum, 0.13 mum, and 65 nm.

Variation in the Helical Structure of Native Collagen

Science.gov (United States)

2014-02-24

notochord were obtained in previous studies [4,10,20–22]. The scaled amplitudes of the central, meridional section of each data set were used to...including helical, structure) from rat tail tendon (collagen type I) and lamprey notochord (collagen type II) show several common features (Figure 5). Of...also a possible consequence of the type II collagen notochord samples being stretched, perhaps to a greater extant then the type I tendon samples to aid

Heterogeneous treatment in the variational nodal method

International Nuclear Information System (INIS)

Fanning, T.H.

1995-01-01

The variational nodal transport method is reduced to its diffusion form and generalized for the treatment of heterogeneous nodes while maintaining nodal balances. Adapting variational methods to heterogeneous nodes requires the ability to integrate over a node with discontinuous cross sections. In this work, integrals are evaluated using composite gaussian quadrature rules, which permit accurate integration while minimizing computing time. Allowing structure within a nodal solution scheme avoids some of the necessity of cross section homogenization, and more accurately defines the intra-nodal flux shape. Ideally, any desired heterogeneity can be constructed within the node; but in reality, the finite set of basis functions limits the practical resolution to which fine detail can be defined within the node. Preliminary comparison tests show that the heterogeneous variational nodal method provides satisfactory results even if some improvements are needed for very difficult, configurations

Seasonal variations of radon concentrations in single-family houses with different sub-structures

DEFF Research Database (Denmark)

Majborn, B.

1992-01-01

Seasonal variations of indoor radon concentrations have been studied in 70 single-family houses selected according to the type of sub-structure and the type of soil underneath the house. Five categories of sub-structure were included - slab-on-grade, crawl space, basement, and combinations...... of basement with slab-on-grade or crawl space. Half of the houses are located on clayey till and the other half on glaciofluvial gravel. In each house radon was measured in a living room and a bedroom, in the basement if present, and in the crawl space if present and accessible. The measurements were made...... with track detectors on a quarterly basis throughout a year. For living rooms and bedrooms the seasonal variations range from being highly significant for the slab-on-grade houses to being insignificant for the crawl space houses. For basements and crawl spaces the geometric mean radon concentrations do...

Variation in Structure and Process of Care in Traumatic Brain Injury: Provider Profiles of European Neurotrauma Centers Participating in the CENTER-TBI Study.

Directory of Open Access Journals (Sweden)

Maryse C Cnossen

Full Text Available The strength of evidence underpinning care and treatment recommendations in traumatic brain injury (TBI is low. Comparative effectiveness research (CER has been proposed as a framework to provide evidence for optimal care for TBI patients. The first step in CER is to map the existing variation. The aim of current study is to quantify variation in general structural and process characteristics among centers participating in the Collaborative European NeuroTrauma Effectiveness Research in Traumatic Brain Injury (CENTER-TBI study.We designed a set of 11 provider profiling questionnaires with 321 questions about various aspects of TBI care, chosen based on literature and expert opinion. After pilot testing, questionnaires were disseminated to 71 centers from 20 countries participating in the CENTER-TBI study. Reliability of questionnaires was estimated by calculating a concordance rate among 5% duplicate questions.All 71 centers completed the questionnaires. Median concordance rate among duplicate questions was 0.85. The majority of centers were academic hospitals (n = 65, 92%, designated as a level I trauma center (n = 48, 68% and situated in an urban location (n = 70, 99%. The availability of facilities for neuro-trauma care varied across centers; e.g. 40 (57% had a dedicated neuro-intensive care unit (ICU, 36 (51% had an in-hospital rehabilitation unit and the organization of the ICU was closed in 64% (n = 45 of the centers. In addition, we found wide variation in processes of care, such as the ICU admission policy and intracranial pressure monitoring policy among centers.Even among high-volume, specialized neurotrauma centers there is substantial variation in structures and processes of TBI care. This variation provides an opportunity to study effectiveness of specific aspects of TBI care and to identify best practices with CER approaches.

A pilot cluster randomized controlled trial of structured goal-setting following stroke.

Science.gov (United States)

Taylor, William J; Brown, Melanie; William, Levack; McPherson, Kathryn M; Reed, Kirk; Dean, Sarah G; Weatherall, Mark

2012-04-01

To determine the feasibility, the cluster design effect and the variance and minimal clinical importance difference in the primary outcome in a pilot study of a structured approach to goal-setting. A cluster randomized controlled trial. Inpatient rehabilitation facilities. People who were admitted to inpatient rehabilitation following stroke who had sufficient cognition to engage in structured goal-setting and complete the primary outcome measure. Structured goal elicitation using the Canadian Occupational Performance Measure. Quality of life at 12 weeks using the Schedule for Individualised Quality of Life (SEIQOL-DW), Functional Independence Measure, Short Form 36 and Patient Perception of Rehabilitation (measuring satisfaction with rehabilitation). Assessors were blinded to the intervention. Four rehabilitation services and 41 patients were randomized. We found high values of the intraclass correlation for the outcome measures (ranging from 0.03 to 0.40) and high variance of the SEIQOL-DW (SD 19.6) in relation to the minimally importance difference of 2.1, leading to impractically large sample size requirements for a cluster randomized design. A cluster randomized design is not a practical means of avoiding contamination effects in studies of inpatient rehabilitation goal-setting. Other techniques for coping with contamination effects are necessary.

Quasilinear parabolic variational inequalities with multi-valued lower-order terms

Science.gov (United States)

Carl, Siegfried; Le, Vy K.

2014-10-01

In this paper, we provide an analytical frame work for the following multi-valued parabolic variational inequality in a cylindrical domain : Find and an such that where is some closed and convex subset, A is a time-dependent quasilinear elliptic operator, and the multi-valued function is assumed to be upper semicontinuous only, so that Clarke's generalized gradient is included as a special case. Thus, parabolic variational-hemivariational inequalities are special cases of the problem considered here. The extension of parabolic variational-hemivariational inequalities to the general class of multi-valued problems considered in this paper is not only of disciplinary interest, but is motivated by the need in applications. The main goals are as follows. First, we provide an existence theory for the above-stated problem under coercivity assumptions. Second, in the noncoercive case, we establish an appropriate sub-supersolution method that allows us to get existence, comparison, and enclosure results. Third, the order structure of the solution set enclosed by sub-supersolutions is revealed. In particular, it is shown that the solution set within the sector of sub-supersolutions is a directed set. As an application, a multi-valued parabolic obstacle problem is treated.

Protein 3D structure computed from evolutionary sequence variation.

Directory of Open Access Journals (Sweden)

Debora S Marks

Full Text Available The evolutionary trajectory of a protein through sequence space is constrained by its function. Collections of sequence homologs record the outcomes of millions of evolutionary experiments in which the protein evolves according to these constraints. Deciphering the evolutionary record held in these sequences and exploiting it for predictive and engineering purposes presents a formidable challenge. The potential benefit of solving this challenge is amplified by the advent of inexpensive high-throughput genomic sequencing.In this paper we ask whether we can infer evolutionary constraints from a set of sequence homologs of a protein. The challenge is to distinguish true co-evolution couplings from the noisy set of observed correlations. We address this challenge using a maximum entropy model of the protein sequence, constrained by the statistics of the multiple sequence alignment, to infer residue pair couplings. Surprisingly, we find that the strength of these inferred couplings is an excellent predictor of residue-residue proximity in folded structures. Indeed, the top-scoring residue couplings are sufficiently accurate and well-distributed to define the 3D protein fold with remarkable accuracy.We quantify this observation by computing, from sequence alone, all-atom 3D structures of fifteen test proteins from different fold classes, ranging in size from 50 to 260 residues, including a G-protein coupled receptor. These blinded inferences are de novo, i.e., they do not use homology modeling or sequence-similar fragments from known structures. The co-evolution signals provide sufficient information to determine accurate 3D protein structure to 2.7-4.8 Å C(α-RMSD error relative to the observed structure, over at least two-thirds of the protein (method called EVfold, details at http://EVfold.org. This discovery provides insight into essential interactions constraining protein evolution and will facilitate a comprehensive survey of the universe of

Upper-Lower Bounds Candidate Sets Searching Algorithm for Bayesian Network Structure Learning

Directory of Open Access Journals (Sweden)

Guangyi Liu

2014-01-01

Full Text Available Bayesian network is an important theoretical model in artificial intelligence field and also a powerful tool for processing uncertainty issues. Considering the slow convergence speed of current Bayesian network structure learning algorithms, a fast hybrid learning method is proposed in this paper. We start with further analysis of information provided by low-order conditional independence testing, and then two methods are given for constructing graph model of network, which is theoretically proved to be upper and lower bounds of the structure space of target network, so that candidate sets are given as a result; after that a search and scoring algorithm is operated based on the candidate sets to find the final structure of the network. Simulation results show that the algorithm proposed in this paper is more efficient than similar algorithms with the same learning precision.

Topological variation in the evolution of new reactions in functionally diverse enzyme superfamilies.

Science.gov (United States)

Meng, Elaine C; Babbitt, Patricia C

2011-06-01

In functionally diverse enzyme superfamilies (SFs), conserved structural and active site features reflect catalytic capabilities 'hard-wired' in each SF architecture. Overlaid on this foundation, evolutionary changes in active site machinery, structural topology and other aspects of structural organization and interactions support the emergence of new reactions, mechanisms, and substrate specificity. This review connects topological with functional variation in each of the haloalkanoic acid dehalogenase (HAD) and vicinal oxygen chelate fold (VOC) SFs and a set of redox-active thioredoxin (Trx)-fold SFs to illustrate a few of the varied themes nature has used to evolve new functions from a limited set of structural scaffolds. Copyright © 2011 Elsevier Ltd. All rights reserved.

Factor Structure of the WPPSI in Mental Health Clinic Settings.

Science.gov (United States)

Haynes, Jack P.; Atkinson, David

1984-01-01

Factor-analyzed the Wechsler Preschool and Primary Scale of Intelligence (WPPSI) scores of emotionally disturbed children (N=181). The results suggested that the structure of intelligence for emotionally disturbed children is similar to that for normal children. WPPSI profile analysis that uses subtest scores may be invalid in clinical settings.…

Hierarchical Sets: Analyzing Pangenome Structure through Scalable Set Visualizations

DEFF Research Database (Denmark)

Pedersen, Thomas Lin

2017-01-01

of hierarchical sets by applying it to a pangenome based on 113 Escherichia and Shigella genomes and find it provides a powerful addition to pangenome analysis. The described clustering algorithm and visualizations are implemented in the hierarchicalSets R package available from CRAN (https...

Geographic variation in age structure and longevity in the nine-spined stickleback (Pungitius pungitius.

Directory of Open Access Journals (Sweden)

Jacquelin DeFaveri

Full Text Available Variation in age and size of mature nine-spined sticklebacks (Pungitius pungitius within and among 16 Fennoscandian populations were assessed using skeletochronology. The average age of individuals in a given population varied from 1.7 to 4.7 years. Fish from pond populations were on average older than those from lake and marine populations, and females tended to be older than males. Reproduction in marine and lake populations commenced typically at an age of two years, whereas that in ponds at an age of three years. The maximum life span of the fish varied from 3 to 7 years. Mean body size within and among populations increased with increasing age, but the habitat and population differences in body size persisted even after accounting for variation in population age (and sex structure. Hence, the population differences in mean body size are not explainable by age differences alone. As such, much of the pronounced intraspecific variation in population age structure can be attributed to delayed maturation and extended longevity of the pond fish. The results are contrasted and discussed in the context of similar data from the three-spined stickleback (Gasterosteus aculeatus occupying the same geographic area.

Normal variation in early parental sensitivity predicts child structural brain development.

Science.gov (United States)

Kok, Rianne; Thijssen, Sandra; Bakermans-Kranenburg, Marian J; Jaddoe, Vincent W V; Verhulst, Frank C; White, Tonya; van IJzendoorn, Marinus H; Tiemeier, Henning

2015-10-01

Early caregiving can have an impact on brain structure and function in children. The influence of extreme caregiving experiences has been demonstrated, but studies on the influence of normal variation in parenting quality are scarce. Moreover, no studies to date have included the role of both maternal and paternal sensitivity in child brain maturation. This study examined the prospective relation between mothers' and fathers' sensitive caregiving in early childhood and brain structure later in childhood. Participants were enrolled in a population-based prenatal cohort. For 191 families, maternal and paternal sensitivity was repeatedly observed when the child was between 1 year and 4 years of age. Head circumference was assessed at 6 weeks, and brain structure was assessed using magnetic resonance imaging (MRI) measurements at 8 years of age. Higher levels of parental sensitivity in early childhood were associated with larger total brain volume (adjusted β = 0.15, p = .01) and gray matter volume (adjusted β = 0.16, p = .01) at 8 years, controlling for infant head size. Higher levels of maternal sensitivity in early childhood were associated with a larger gray matter volume (adjusted β = 0.13, p = .04) at 8 years, independent of infant head circumference. Associations with maternal versus paternal sensitivity were not significantly different. Normal variation in caregiving quality is related to markers of more optimal brain development in children. The results illustrate the important role of both mothers and fathers in child brain development. Copyright © 2015 American Academy of Child and Adolescent Psychiatry. Published by Elsevier Inc. All rights reserved.

Variational Monte Carlo studies of electromagnetic structure of few-body nuclei

International Nuclear Information System (INIS)

Schiavilla, R.

1990-01-01

The electromagnetic structure and dynamic response of A = 2, 3 and 4 nuclei are studied with the Variational Monte Carlo method by using wave functions based on realistic nuclear interactions. Recent results obtained for the elastic form factors of 2 H, 3 H, 3 He and 4 He, the radiative neutron capture on 3 He at thermal energies, and the reaction 4 He(e,e'p) 3 H are reported. 24 refs., 5 figs

Calculations of wavefunctions and energies of electron system in Coulomb potential by variational method without a basis set

International Nuclear Information System (INIS)

Bykov, V.P.; Gerasimov, A.V.

1992-08-01

A new variational method without a basis set for calculation of the eigenvalues and eigenfunctions of Hamiltonians is suggested. The expansion of this method for the Coulomb potentials is given. Calculation of the energy and charge distribution in the two-electron system for different values of the nuclear charge Z is made. It is shown that at small Z the Coulomb forces disintegrate the electron cloud into two clots. (author). 3 refs, 4 figs, 1 tab

Recruitment of PfSET2 by RNA polymerase II to variant antigen encoding loci contributes to antigenic variation in P. falciparum.

Directory of Open Access Journals (Sweden)

Uchechi E Ukaegbu

2014-01-01

Full Text Available Histone modifications are important regulators of gene expression in all eukaryotes. In Plasmodium falciparum, these epigenetic marks regulate expression of genes involved in several aspects of host-parasite interactions, including antigenic variation. While the identities and genomic positions of many histone modifications have now been cataloged, how they are targeted to defined genomic regions remains poorly understood. For example, how variant antigen encoding loci (var are targeted for deposition of unique histone marks is a mystery that continues to perplex the field. Here we describe the recruitment of an ortholog of the histone modifier SET2 to var genes through direct interactions with the C-terminal domain (CTD of RNA polymerase II. In higher eukaryotes, SET2 is a histone methyltransferase recruited by RNA pol II during mRNA transcription; however, the ortholog in P. falciparum (PfSET2 has an atypical architecture and its role in regulating transcription is unknown. Here we show that PfSET2 binds to the unphosphorylated form of the CTD, a property inconsistent with its recruitment during mRNA synthesis. Further, we show that H3K36me3, the epigenetic mark deposited by PfSET2, is enriched at both active and silent var gene loci, providing additional evidence that its recruitment is not associated with mRNA production. Over-expression of a dominant negative form of PfSET2 designed to disrupt binding to RNA pol II induced rapid var gene expression switching, confirming both the importance of PfSET2 in var gene regulation and a role for RNA pol II in its recruitment. RNA pol II is known to transcribe non-coding RNAs from both active and silent var genes, providing a possible mechanism by which it could recruit PfSET2 to var loci. This work unifies previous reports of histone modifications, the production of ncRNAs, and the promoter activity of var introns into a mechanism that contributes to antigenic variation by malaria parasites.

Heat Flow Variation along the Nankai Trough Floor Correlated with the Structure of the Shikoku Basin Oceanic Crust

Science.gov (United States)

Yamano, M.; Kawada, Y.; Gao, X.

2016-12-01

Surface heat flow observed on the floor of the Nankai Trough, near the trench axis, is highly variable and does not well correspond to the seafloor age of the incoming Philippine Sea plate (Shikoku Basin). Recent detailed measurements between 133.5°E and 137°E revealed that heat flow on the trough floor significantly varies along the trough. The most conspicuous variation is found around 136°E. Heat flow is extremely high and variable between 135°E and 136°E, much higher than the value estimated from the age. On the east of 136°E, heat flow gradually decreases eastward over 50 km to the value nearly consistent with the age with no appreciable scatter. Elevated heat flow on the trough floor can be attributed to vigorous fluid circulation in a permeable layer (aquifer) in the subducted oceanic crust, which efficiently transports heat upward along the plate interface (Spinelli and Wang, 2008). The heat flow variation around 136°E may therefore arise from variation in the permeability structure of the crustal aquifer. A probable cause of the heterogeneity in the aquifer permeability is a structure boundary in the incoming Shikoku Basin, the boundary between the younger part on the west formed by spreading in NE-SW direction and the older part on the east formed by E-W spreading. It is located around 136°E, about the same place as the heat flow distribution boundary. A possible additional source of variation in the permeability structure is the geometry of the subducted Philippine Sea plate. A prominent bend in the subducted plate between 135°E and 136°E, which corresponds to the high heat flow area on the trough floor, may have fractured the oceanic crust and enhanced the aquifer permeability. We evaluated the influence of variations in the aquifer permeability on the thermal structure through 3D numerical modelling using a high thermal-conductivity proxy for heat transport by fluid flow. A sharp along-strike change in the permeability of the subducted

The geometric approach to sets of ordinary differential equations and Hamiltonian dynamics

Science.gov (United States)

Estabrook, F. B.; Wahlquist, H. D.

1975-01-01

The calculus of differential forms is used to discuss the local integration theory of a general set of autonomous first order ordinary differential equations. Geometrically, such a set is a vector field V in the space of dependent variables. Integration consists of seeking associated geometric structures invariant along V: scalar fields, forms, vectors, and integrals over subspaces. It is shown that to any field V can be associated a Hamiltonian structure of forms if, when dealing with an odd number of dependent variables, an arbitrary equation of constraint is also added. Families of integral invariants are an immediate consequence. Poisson brackets are isomorphic to Lie products of associated CT-generating vector fields. Hamilton's variational principle follows from the fact that the maximal regular integral manifolds of a closed set of forms must include the characteristics of the set.

Genetic Variation in Schizophrenia Liability is Shared With Intellectual Ability and Brain Structure.

Science.gov (United States)

Bohlken, Marc M; Brouwer, Rachel M; Mandl, René C W; Kahn, René S; Hulshoff Pol, Hilleke E

2016-09-01

Alterations in intellectual ability and brain structure are important genetic markers for schizophrenia liability. How variations in these phenotypes interact with variance in schizophrenia liability due to genetic or environmental factors is an area of active investigation. Studying these genetic markers using a multivariate twin modeling approach can provide novel leads for (genetic) pathways of schizophrenia development. In a sample of 70 twins discordant for schizophrenia and 130 healthy control twins, structural equation modeling was applied to quantify unique contributions of genetic and environmental factors on human brain structure (cortical thickness, cortical surface and global white matter fractional anisotropy [FA]), intellectual ability and schizophrenia liability. In total, up to 28.1% of the genetic variance (22.8% of total variance) in schizophrenia liability was shared with intelligence quotient (IQ), global-FA, cortical thickness, and cortical surface. The strongest contributor was IQ, sharing on average 16.4% of the genetic variance in schizophrenia liability, followed by cortical thickness (6.3%), global-FA (4.7%) and cortical surface (0.5%). Furthermore, we found that up to 57.4% of the variation due to environmental factors (4.6% of total variance) in schizophrenia was shared with IQ (34.2%) and cortical surface (13.4%). Intellectual ability, FA and cortical thickness show significant and independent shared genetic variance with schizophrenia liability. This suggests that measuring brain-imaging phenotypes helps explain genetic variance in schizophrenia liability that is not captured by variation in IQ. © The Author 2016. Published by Oxford University Press on behalf of the Maryland Psychiatric Research Center. All rights reserved. For permissions, please email: journals.permissions@oup.com.

Influence of variations in creep curve on creep behavior of a high-temperature structure

International Nuclear Information System (INIS)

Hada, Kazuhiko

1986-01-01

It is one of the key issues for a high-temperature structural design guideline to evaluate the influence of variations in creep curve on the creep behavior of a high-temperature structure. In the present paper, a comparative evaluation was made to clarify such influence. Additional consideration was given to the influence of the relationship between creep rupture life and minimum creep rate, i.e., the Monkman-Grant's relationship, on the creep damage evaluation. The consideration suggested that the Monkman-Grant's relationship be taken into account in evaluating the creep damage behavior, especially the creep damage variations. However, it was clarified that the application of the creep damage evaluation rule of ASME B and P.V. Code Case N-47 to the ''standard case'' which was predicted from the average creep property would predict the creep damage on the safe side. (orig./GL)

Establishing a Set of Macroeconomic Factors Explaining Variation Over Time of Performance in Business Sectors

Directory of Open Access Journals (Sweden)

Audrius Dzikevičius

2016-06-01

Full Text Available With increasing competitiveness of companies and business sectors in the domestic markets of Lithuania, economic units are frequently confronted with the lack of methods for more detailed analysis of external factors explaining the variation over time of corporate financial indicators. The analysis or forecasting of financial indicators is usually linked with the development of a stock market or undertaken to estimate the probability of bankruptcy. However, there is a lack of studies aimed at identifying links between macroeconomic factors and financial performance indicators and explaining their variation over time. To serve that purpose, the factors of the macroeconomic environment that are most significant for certain economic activities have been identified and analysed to enable explaining the variation over time patterns of corporate financial indicators. The analysis covers economic performance, i.e. financial performance indicators and their links with macroeconomic factors, in 89 business sectors of Lithuania at a three-digit level of NACE 2 ed. The findings of the research indicate that the unemployment level in the country, the volume of export and import and the GDP are the most important macroeconomic factors that can be used to forecast different profitability, financial leverage, liquidity and other financial performance indicators of individual business sectors or companies. The research has not unfolded any significant differences between business sectors therefore the above factors are considered generic macroeconomic factors enabling to explain financial performance indicators of the 89 business sectors. Hence, special attention has to be paid to identifying and analysing specific factors and assessing the causal link. When established, the set of such factors provides a framework for building of a model to forecast business sector financial indicators.

Determination of protein and solvent volumes in protein crystals from contrast variation data

Energy Technology Data Exchange (ETDEWEB)

Badger, J. [Brandeis Univ., Waltham, MA (United States)

1994-12-31

By varying the relative values of protein and solvent scattering densities in a crystal, it is possible to obtain information on the shape and dimensions of protein molecular envelopes. Neutron diffraction methods are ideally suited to these contrast variation experiments because H/D exchange leads to large differential changes in the protein and solvent scattering densities and is structurally non-perturbing. Low resolution structure factors have been measured from cubic insulin crystals with differing H/D contents. Structure factors calculated from a simple binary density model, in which uniform scattering densities represent the protein and solvent volumes in the crystals, were compared with these data. The contrast variation differences in the sets of measured structure factors were found to be accurately fitted by this simple model. Trial applications to two problems in crystal structure determination illustrate how this fact may be exploited. (1) A translation function that employs contrast variation data gave a sharp minimum within 1-9{Angstrom} of the correctly positioned insulin molecule and is relatively insensitive to errors in the atomic model. (2) An ab initio phasing method for the contrast variation data, based on analyzing histograms of the density distributions in trial maps, was found to recover the correct molecular envelope.

Monitoring of Students' Interaction in Online Learning Settings by Structural Network Analysis and Indicators.

Science.gov (United States)

Ammenwerth, Elske; Hackl, Werner O

2017-01-01

Learning as a constructive process works best in interaction with other learners. Support of social interaction processes is a particular challenge within online learning settings due to the spatial and temporal distribution of participants. It should thus be carefully monitored. We present structural network analysis and related indicators to analyse and visualize interaction patterns of participants in online learning settings. We validate this approach in two online courses and show how the visualization helps to monitor interaction and to identify activity profiles of learners. Structural network analysis is a feasible approach for an analysis of the intensity and direction of interaction in online learning settings.

Generalized bi-quasi-variational inequalities for quasi-semi-monotone and bi-quasi-semi-monotone operators with applications in non-compact settings and minimization problems

Directory of Open Access Journals (Sweden)

Chowdhury Molhammad SR

2000-01-01

Full Text Available Results are obtained on existence theorems of generalized bi-quasi-variational inequalities for quasi-semi-monotone and bi-quasi-semi-monotone operators in both compact and non-compact settings. We shall use the concept of escaping sequences introduced by Border (Fixed Point Theorem with Applications to Economics and Game Theory, Cambridge University Press, Cambridge, 1985 to obtain results in non-compact settings. Existence theorems on non-compact generalized bi-complementarity problems for quasi-semi-monotone and bi-quasi-semi-monotone operators are also obtained. Moreover, as applications of some results of this paper on generalized bi-quasi-variational inequalities, we shall obtain existence of solutions for some kind of minimization problems with quasi- semi-monotone and bi-quasi-semi-monotone operators.

Multistep Hybrid Extragradient Method for Triple Hierarchical Variational Inequalities

Directory of Open Access Journals (Sweden)

Zhao-Rong Kong

2013-01-01

Full Text Available We consider a triple hierarchical variational inequality problem (THVIP, that is, a variational inequality problem defined over the set of solutions of another variational inequality problem which is defined over the intersection of the fixed point set of a strict pseudocontractive mapping and the solution set of the classical variational inequality problem. Moreover, we propose a multistep hybrid extragradient method to compute the approximate solutions of the THVIP and present the convergence analysis of the sequence generated by the proposed method. We also derive a solution method for solving a system of hierarchical variational inequalities (SHVI, that is, a system of variational inequalities defined over the intersection of the fixed point set of a strict pseudocontractive mapping and the solution set of the classical variational inequality problem. Under very mild conditions, it is proven that the sequence generated by the proposed method converges strongly to a unique solution of the SHVI.

Studying the properties of Variational Data Assimilation Methods by Applying a Set of Test-Examples

DEFF Research Database (Denmark)

Thomsen, Per Grove; Zlatev, Zahari

2007-01-01

and backward computations are carried out by using the model under consideration and its adjoint equations (both the model and its adjoint are defined by systems of differential equations). The major difficulty is caused by the huge increase of the computational load (normally by a factor more than 100...... assimilation method (numerical algorithms for solving differential equations, splitting procedures and optimization algorithms) have been studied by using these tests. The presentation will include results from testing carried out in the study.......he variational data assimilation methods can successfully be used in different fields of science and engineering. An attempt to utilize available sets of observations in the efforts to improve (i) the models used to study different phenomena (ii) the model results is systematically carried out when...

Analysis of successive data sets

NARCIS (Netherlands)

Spreeuwers, Lieuwe Jan; Breeuwer, Marcel; Haselhoff, Eltjo Hans

2008-01-01

The invention relates to the analysis of successive data sets. A local intensity variation is formed from such successive data sets, that is, from data values in successive data sets at corresponding positions in each of the data sets. A region of interest is localized in the individual data sets on

Analysis of successive data sets

NARCIS (Netherlands)

Spreeuwers, Lieuwe Jan; Breeuwer, Marcel; Haselhoff, Eltjo Hans

2002-01-01

The invention relates to the analysis of successive data sets. A local intensity variation is formed from such successive data sets, that is, from data values in successive data sets at corresponding positions in each of the data sets. A region of interest is localized in the individual data sets on

An Optimized, Grid Independent, Narrow Band Data Structure for High Resolution Level Sets

DEFF Research Database (Denmark)

Nielsen, Michael Bang; Museth, Ken

2004-01-01

enforced by the convex boundaries of an underlying cartesian computational grid. Here we present a novel very memory efficient narrow band data structure, dubbed the Sparse Grid, that enables the representation of grid independent high resolution level sets. The key features our new data structure are...

The influence of topographic variation on forest structure in two woody plant communities: A remote sensing approach

Energy Technology Data Exchange (ETDEWEB)

Ediriweera, S.; Danaher, T.; Pathirana, S.

2016-07-01

Aim of study: The study aimed to characterise variation in structural attributes of vegetation in relation to variations in topographic position using LIDAR data over landscapes. Area of study: The study was conducted in open canopy eucalypt-dominated forest (Richmond Range National Park-RRNP) and closed canopy subtropical rainforest (Border Ranges National Park-BRNP) in north-eastern New South Wales, Australia. Material and Methods: one metre resolution digital canopy height model (CHM) was extracted from the LIDAR data and used to estimate maximum overstorey height and crown area. LIDAR fractional cover representing the photosynthetic and non-photosynthetic component of canopy was calculated using LIDAR points aggregated into 50 m spatial bins. Potential solar insolation, Topographic Wetness Index (TWI), slope and the elevation were processed using LIDAR derived digital elevation models. Main results: No relationship was found between maximum overstorey height and insolation gradient in the BRNP. Maximum overstorey height decreased with increasing insolation in the RRNP (R2 0.45). Maximum overstorey height increased with increasing TWI in the RRNP. Average crown area decreased with increasing insolation in both study areas. LIDAR fractional cover decreased with increasing insolation (R2 0.54), and increased with increasing TWI (R2 0.57) in the RRNP. Research highlights: The characterization of structural parameters of vegetation in relation to the variation of the topography was possible in eucalyptus dominated open canopy forest. No reportable difference in variation of structural elements of vegetation was detected with topographic variation of subtropical rainforest. (Author)

Variational and quasi-variational inequalities in mechanics

CERN Document Server

Kravchuk, Alexander S

2007-01-01

The essential aim of the present book is to consider a wide set of problems arising in the mathematical modelling of mechanical systems under unilateral constraints. In these investigations elastic and non-elastic deformations, friction and adhesion phenomena are taken into account. All the necessary mathematical tools are given: local boundary value problem formulations, construction of variational equations and inequalities, and the transition to minimization problems, existence and uniqueness theorems, and variational transformations (Friedrichs and Young-Fenchel-Moreau) to dual and saddle-point search problems. Important new results concern contact problems with friction. The Coulomb friction law and some others are considered, in which relative sliding velocities appear. The corresponding quasi-variational inequality is constructed, as well as the appropriate iterative method for its solution. Outlines of the variational approach to non-stationary and dissipative systems and to the construction of the go...

Consistent structures and interactions by density functional theory with small atomic orbital basis sets.

Science.gov (United States)

Grimme, Stefan; Brandenburg, Jan Gerit; Bannwarth, Christoph; Hansen, Andreas

2015-08-07

A density functional theory (DFT) based composite electronic structure approach is proposed to efficiently compute structures and interaction energies in large chemical systems. It is based on the well-known and numerically robust Perdew-Burke-Ernzerhoff (PBE) generalized-gradient-approximation in a modified global hybrid functional with a relatively large amount of non-local Fock-exchange. The orbitals are expanded in Ahlrichs-type valence-double zeta atomic orbital (AO) Gaussian basis sets, which are available for many elements. In order to correct for the basis set superposition error (BSSE) and to account for the important long-range London dispersion effects, our well-established atom-pairwise potentials are used. In the design of the new method, particular attention has been paid to an accurate description of structural parameters in various covalent and non-covalent bonding situations as well as in periodic systems. Together with the recently proposed three-fold corrected (3c) Hartree-Fock method, the new composite scheme (termed PBEh-3c) represents the next member in a hierarchy of "low-cost" electronic structure approaches. They are mainly free of BSSE and account for most interactions in a physically sound and asymptotically correct manner. PBEh-3c yields good results for thermochemical properties in the huge GMTKN30 energy database. Furthermore, the method shows excellent performance for non-covalent interaction energies in small and large complexes. For evaluating its performance on equilibrium structures, a new compilation of standard test sets is suggested. These consist of small (light) molecules, partially flexible, medium-sized organic molecules, molecules comprising heavy main group elements, larger systems with long bonds, 3d-transition metal systems, non-covalently bound complexes (S22 and S66×8 sets), and peptide conformations. For these sets, overall deviations from accurate reference data are smaller than for various other tested DFT methods

Consistent structures and interactions by density functional theory with small atomic orbital basis sets

International Nuclear Information System (INIS)

Grimme, Stefan; Brandenburg, Jan Gerit; Bannwarth, Christoph; Hansen, Andreas

2015-01-01

A density functional theory (DFT) based composite electronic structure approach is proposed to efficiently compute structures and interaction energies in large chemical systems. It is based on the well-known and numerically robust Perdew-Burke-Ernzerhoff (PBE) generalized-gradient-approximation in a modified global hybrid functional with a relatively large amount of non-local Fock-exchange. The orbitals are expanded in Ahlrichs-type valence-double zeta atomic orbital (AO) Gaussian basis sets, which are available for many elements. In order to correct for the basis set superposition error (BSSE) and to account for the important long-range London dispersion effects, our well-established atom-pairwise potentials are used. In the design of the new method, particular attention has been paid to an accurate description of structural parameters in various covalent and non-covalent bonding situations as well as in periodic systems. Together with the recently proposed three-fold corrected (3c) Hartree-Fock method, the new composite scheme (termed PBEh-3c) represents the next member in a hierarchy of “low-cost” electronic structure approaches. They are mainly free of BSSE and account for most interactions in a physically sound and asymptotically correct manner. PBEh-3c yields good results for thermochemical properties in the huge GMTKN30 energy database. Furthermore, the method shows excellent performance for non-covalent interaction energies in small and large complexes. For evaluating its performance on equilibrium structures, a new compilation of standard test sets is suggested. These consist of small (light) molecules, partially flexible, medium-sized organic molecules, molecules comprising heavy main group elements, larger systems with long bonds, 3d-transition metal systems, non-covalently bound complexes (S22 and S66×8 sets), and peptide conformations. For these sets, overall deviations from accurate reference data are smaller than for various other tested DFT

Constraints on a possible variation of the fine structure constant from galaxy cluster data

Energy Technology Data Exchange (ETDEWEB)

Holanda, R.F.L. [Departamento de Física, Universidade Estadual da Paraíba, 58429-500, Campina Grande – PB (Brazil); Landau, S.J.; Sánchez G, I.E. [Departamento de Física, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, and IFIBA, CONICET, Ciudad Universitaria – PabI, Buenos Aires 1428 (Argentina); Alcaniz, J.S. [Departamento de Astronomia, Observatório Nacional, 20921-400, Rio de Janeiro – RJ (Brazil); Busti, V.C., E-mail: holanda@uepb.edu.br, E-mail: slandau@df.uba.ar, E-mail: alcaniz@on.br, E-mail: isg.cos@gmail.com, E-mail: vinicius.busti@astro.iag.usp.br [Departamento de Física Matemática, Instituto de Física, Universidade de São Paulo, CP 66318, 05508-090, São Paulo – SP (Brazil)

2016-05-01

We propose a new method to probe a possible time evolution of the fine structure constant α from X-ray and Sunyaev-Zel'dovich measurements of the gas mass fraction ( f {sub gas}) in galaxy clusters. Taking into account a direct relation between variations of α and violations of the distance-duality relation, we discuss constraints on α for a class of dilaton runaway models. Although not yet competitive with bounds from high- z quasar absorption systems, our constraints, considering a sample of 29 measurements of f {sub gas}, in the redshift interval 0.14 < z < 0.89, provide an independent estimate of α variation at low and intermediate redshifts. Furthermore, current and planned surveys will provide a larger amount of data and thus allow to improve the limits on α variation obtained in the present analysis.

Effects of manual threshold setting on image analysis results of a sandstone sample structural characterization by X-ray microtomography

International Nuclear Information System (INIS)

Moreira, Anderson C.; Fernandes, Celso P.; Fernandes, Jaquiel S.; Marques, Leonardo C.; Appoloni, Carlos R.; Nagata, Rodrigo

2009-01-01

X-ray microtomography is a nondestructive nuclear technique widely applied for samples structural characterization. This methodology permits the investigation of materials porous phase, without special sample preparation, generating bidimensional images of the irradiated sample. The images are generated by the linear attenuation coefficient mapping of the sample. In order to do a quantitative characterization, the images have to be binarized, separating porous phase from the material matrix. The choice of the correct threshold in the grey level histogram is an important and discerning procedure for the binary images creation. Slight variations of the threshold level led to substantial variations in physical parameters determination, like porosity and pore size distribution values. The aim of this work is to evaluate these variations based on some manual threshold setting. Employing Imago image analysis software, four operators determined the porosity and pore size distribution of a sandstone sample by image analysis. The microtomography measurements were accomplished with the following scan conditions: 60 kV, 165 μA, 1 mm Al filter, 0.45 deg step size and 180.0 deg total rotation angle with and 3.8 μm and 11 μm spatial resolution. The global average porosity values, determined by the operators, range from 27.8 to 32.4 % for 3.8 μm spatial resolution and 12.3 to 28.3 % for 11 μm spatial resolution. Percentage differences among the pore size distributions were also found. For the same pore size range, 5.5 % and 17.1 %, for 3.8 μm and 11 μm spatial resolutions respectively, were noted. (author)

Sets, Planets, and Comets

Science.gov (United States)

Baker, Mark; Beltran, Jane; Buell, Jason; Conrey, Brian; Davis, Tom; Donaldson, Brianna; Detorre-Ozeki, Jeanne; Dibble, Leila; Freeman, Tom; Hammie, Robert; Montgomery, Julie; Pickford, Avery; Wong, Justine

2013-01-01

Sets in the game "Set" are lines in a certain four-dimensional space. Here we introduce planes into the game, leading to interesting mathematical questions, some of which we solve, and to a wonderful variation on the game "Set," in which every tableau of nine cards must contain at least one configuration for a player to pick up.

Insights into structural variations and genome rearrangements in prokaryotic genomes.

Science.gov (United States)

Periwal, Vinita; Scaria, Vinod

2015-01-01

Structural variations (SVs) are genomic rearrangements that affect fairly large fragments of DNA. Most of the SVs such as inversions, deletions and translocations have been largely studied in context of genetic diseases in eukaryotes. However, recent studies demonstrate that genome rearrangements can also have profound impact on prokaryotic genomes, leading to altered cell phenotype. In contrast to single-nucleotide variations, SVs provide a much deeper insight into organization of bacterial genomes at a much better resolution. SVs can confer change in gene copy number, creation of new genes, altered gene expression and many other functional consequences. High-throughput technologies have now made it possible to explore SVs at a much refined resolution in bacterial genomes. Through this review, we aim to highlight the importance of the less explored field of SVs in prokaryotic genomes and their impact. We also discuss its potential applicability in the emerging fields of synthetic biology and genome engineering where targeted SVs could serve to create sophisticated and accurate genome editing. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Effects of temperature variations on guided waves propagating in composite structures

Science.gov (United States)

Shoja, Siavash; Berbyuk, Viktor; Boström, Anders

2016-04-01

Effects of temperature on guided waves propagating in composite materials is a well-known problem which has been investigated in many studies. The majority of the studies is focused on effects of high temperature. Understanding the effects of low temperature has major importance in composite structures and components which are operating in cold climate conditions such as e.g. wind turbines operating in cold climate regions. In this study first the effects of temperature variations on guided waves propagating in a composite plate is investigated experimentally in a cold climate chamber. The material is a common material used to manufacture rotor blades of wind turbines. The temperature range is 25°C to -25°C and effects of temperature variations on amplitude and phase shift of the received signal are investigated. In order to apply the effects of lowering the temperature on the received signal, the Baseline Signal Stretch (BSS) method is modified and used. The modification is based on decomposing the signal into symmetric and asymmetric modes and applying two different stretch factors on each of them. Finally the results obtained based on the new method is compared with the results of application of BSS with one stretch factor and experimental measurements. Comparisons show that an improvement is obtained using the BSS with the mode decomposition method at temperature variations of more than 25°C.

Variation and Mathematics Pedagogy

Science.gov (United States)

Leung, Allen

2012-01-01

This discussion paper put forwards variation as a theme to structure mathematical experience and mathematics pedagogy. Patterns of variation from Marton's Theory of Variation are understood and developed as types of variation interaction that enhance mathematical understanding. An idea of a discernment unit comprising mutually supporting variation…

Variation in Approaches to European Works Councils in Multinational Companies

OpenAIRE

Paul Marginson; Jonathan Lavelle; Javier Quintanilla; Duncan Adam; Roc'o S?nchez-Mangas

2013-01-01

Drawing on a unique international data set of multinational companies' employment practices, the authors use logistic regression analysis to address variation in the existence of and management practice toward transnational social dialogue through European Works Councils (EWCs). Adopting a contingency perspective, they find that the degree of internationalization of companies' operations and management organization, international HR structure, and the presence of workforce organization exerci...

Structure analyses of swollen rubber-filler systems by using contrast variation Small angle neutron scattering (SANS)

International Nuclear Information System (INIS)

Takenaka, Mikihito; Nishitsuji, Shotaro; Yamaguchi, Daisuke; Koizumi, Satoshi

2009-01-01

Full text: The polymer layers absorbed on silica particles in rubber-silica systems have investigated with contrast variation small-angle neutron scattering (SANS) method. The scattering intensities of specimens swollen by the solvents having various scattering length densities were measured. The contrast variation SANS for the specimens yielded partial scattering functions: the scattering function for polymer-polymer correlation SPP(q), the scattering function for silica- silica correlation SSS(q), and the scattering function for polymer- silica correlation SPS(q). The analyses of SSS(q) explored the hierarchical structures formed by silica particles. The analyses of SPS(q) and SSS(q) clarified the existence of dense polymer layers around silica aggregates. Several characteristic parameters are estimated from the analyses, such as the size of aggregates, the thickness of layers, the volume fractions of polymer of layers and matrix, and the correlation length of the matrix network. The contrast variation SANS is found to be a powerful tool of the analyses of the structures of the rubber-filler systems. (author)

Climatic factors, genetic structure and phenotypic variation in English yew (Taxus baccata L.)

OpenAIRE

Mayol, Maria; Berganzo, Elisa; Burgarella, Concetta; González-Martínez, Santiago C.; Grivet, Delphine; Vendramin, Giovanni G.; Vincenot, Lucie; Riba, Miquel

2018-01-01

Influence of climatic factors on genetic structure and phenotypic variation in English yew (Taxus baccata L.) Conference "Adapting to global change in the Mediterranean hotspot" (Seville, 18-20 September 2013) Mediterranean forests constitute long-term reservoirs of biodiversity and adaptive potential. As compared with their central or northern European counterparts, Mediterranean forests are characterized by highly heterogeneous and fragmented environments, ...

Automatic Fontanel Extraction from Newborns' CT Images Using Variational Level Set

Science.gov (United States)

Kazemi, Kamran; Ghadimi, Sona; Lyaghat, Alireza; Tarighati, Alla; Golshaeyan, Narjes; Abrishami-Moghaddam, Hamid; Grebe, Reinhard; Gondary-Jouet, Catherine; Wallois, Fabrice

A realistic head model is needed for source localization methods used for the study of epilepsy in neonates applying Electroencephalographic (EEG) measurements from the scalp. The earliest models consider the head as a series of concentric spheres, each layer corresponding to a different tissue whose conductivity is assumed to be homogeneous. The results of the source reconstruction depend highly on the electric conductivities of the tissues forming the head.The most used model is constituted of three layers (scalp, skull, and intracranial). Most of the major bones of the neonates’ skull are ossified at birth but can slightly move relative to each other. This is due to the sutures, fibrous membranes that at this stage of development connect the already ossified flat bones of the neurocranium. These weak parts of the neurocranium are called fontanels. Thus it is important to enter the exact geometry of fontaneles and flat bone in a source reconstruction because they show pronounced in conductivity. Computer Tomography (CT) imaging provides an excellent tool for non-invasive investigation of the skull which expresses itself in high contrast to all other tissues while the fontanels only can be identified as absence of bone, gaps in the skull formed by flat bone. Therefore, the aim of this paper is to extract the fontanels from CT images applying a variational level set method. We applied the proposed method to CT-images of five different subjects. The automatically extracted fontanels show good agreement with the manually extracted ones.

Beyond sex differences: new approaches for thinking about variation in brain structure and function.

Science.gov (United States)

Joel, Daphna; Fausto-Sterling, Anne

2016-02-19

In the study of variation in brain structure and function that might relate to sex and gender, language matters because it frames our research questions and methods. In this article, we offer an approach to thinking about variation in brain structure and function that pulls us outside the sex differences formulation. We argue that the existence of differences between the brains of males and females does not unravel the relations between sex and the brain nor is it sufficient to characterize a population of brains. Such characterization is necessary for studying sex effects on the brain as well as for studying brain structure and function in general. Animal studies show that sex interacts with environmental, developmental and genetic factors to affect the brain. Studies of humans further suggest that human brains are better described as belonging to a single heterogeneous population rather than two distinct populations. We discuss the implications of these observations for studies of brain and behaviour in humans and in laboratory animals. We believe that studying sex effects in context and developing or adopting analytical methods that take into account the heterogeneity of the brain are crucial for the advancement of human health and well-being. © 2016 The Author(s).

Fabrication and characterization of anode catalyst layers with structural variations for DMFC

Science.gov (United States)

Wang, Dazhi; Shi, Peng; Zhou, Peng; Mao, Qing; Liang, Junsheng; Wang, Suli; Li, Yang; Ren, Tongqun; Sun, Gongquan

2018-04-01

In this work, the electrohydrodynamic jet (E-Jet) Layer-by-Layer (LbL) deposition technique was employed to produce anode catalyst layer (CL) structure for direct methanol fuel cells (DMFC). The CLs with different thickness and porosity were fabricated with the control of the E-Jet deposition parameters. Then, the deposited anode CLs with structural variations were assembled to membrane electrode assemblies (MEAs). The results showed that the anode CL with higher porosity contributed higher dispersed catalyst, which further induced greater electrochemical active surface area (ESA) and higher performance. At optimized working condition the anode CL with high-dispersed catalyst of was produced using the E-Jet LbL deposition technique. It was observed that the peak power density is 72.8 mW cm‑2 for the cell having a porosity of 0.63, which has an increase of about 33% after modification of the CL structure.

Harnessing cell-to-cell variations to probe bacterial structure and biophysics

Science.gov (United States)

Cass, Julie A.

Advances in microscopy and biotechnology have given us novel insights into cellular biology and physics. While bacteria were long considered to be relatively unstructured, the development of fluorescence microscopy techniques, and spatially and temporally resolved high-throughput quantitative studies, have uncovered that the bacterial cell is highly organized, and its structure rigorously maintained. In this thesis I will describe our gateTool software, designed to harness cell-to-cell variations to probe bacterial structure, and discuss two exciting aspects of structure that we have employed gateTool to investigate: (i) chromosome organization and the cellular mechanisms for controlling DNA dynamics, and (ii) the study of cell wall synthesis, and how the genes in the synthesis pathway impact cellular shape. In the first project, we develop a spatial and temporal mapping of cell-cycle-dependent chromosomal organization, and use this quantitative map to discover that chromosomal loci segregate from midcell with universal dynamics. In the second project, I describe preliminary time- lapse and snapshot imaging analysis suggesting phentoypical coherence across peptidoglycan synthesis pathways.

Visual signal detection in structured backgrounds. II. Effects of contrast gain control, background variations, and white noise

Science.gov (United States)

Eckstein, M. P.; Ahumada, A. J. Jr; Watson, A. B.

1997-01-01

Studies of visual detection of a signal superimposed on one of two identical backgrounds show performance degradation when the background has high contrast and is similar in spatial frequency and/or orientation to the signal. To account for this finding, models include a contrast gain control mechanism that pools activity across spatial frequency, orientation and space to inhibit (divisively) the response of the receptor sensitive to the signal. In tasks in which the observer has to detect a known signal added to one of M different backgrounds grounds due to added visual noise, the main sources of degradation are the stochastic noise in the image and the suboptimal visual processing. We investigate how these two sources of degradation (contrast gain control and variations in the background) interact in a task in which the signal is embedded in one of M locations in a complex spatially varying background (structured background). We use backgrounds extracted from patient digital medical images. To isolate effects of the fixed deterministic background (the contrast gain control) from the effects of the background variations, we conduct detection experiments with three different background conditions: (1) uniform background, (2) a repeated sample of structured background, and (3) different samples of structured background. Results show that human visual detection degrades from the uniform background condition to the repeated background condition and degrades even further in the different backgrounds condition. These results suggest that both the contrast gain control mechanism and the background random variations degrade human performance in detection of a signal in a complex, spatially varying background. A filter model and added white noise are used to generate estimates of sampling efficiencies, an equivalent internal noise, an equivalent contrast-gain-control-induced noise, and an equivalent noise due to the variations in the structured background.

Variations in fresh fruit and vegetable quality by store type, urban-rural setting and neighbourhood deprivation in Scotland.

Science.gov (United States)

Cummins, Steven; Smith, Dianna M; Taylor, Mathew; Dawson, John; Marshall, David; Sparks, Leigh; Anderson, Annie S

2009-11-01

Neighbourhood differences in access to fresh fruit and vegetables may explain social inequalities in diet. Investigations have focused on variations in cost and availability as barriers to the purchase and consumption of fresh produce; investigations of quality have been neglected. Here we investigate whether produce quality systematically varies by food store type, rural-urban location and neighbourhood deprivation in a selection of communities across Scotland. Cross-sectional survey of twelve fresh fruit and vegetable items in 288 food stores in ten communities across Scotland. Communities were selected to reflect a range of urban-rural settings and a food retail census was conducted in each location. The quality of twelve fruit and vegetable items within each food store was evaluated. Data from the Scottish Executive were used to characterise each small area by deprivation and urban-rural classification. Scotland. Quality of fruit and vegetables within the surveyed stores was high. Medium-sized stores, stores in small town and rural areas, and stores in more affluent areas tended to have the highest-quality fresh fruit and vegetables. Stores where food is secondary, stores in urban settings and stores in more deprived areas tended have the lowest-quality fresh produce. Although differences in quality were not always statistically significant, patterns were consistent for the majority of fruit and vegetable items. The study provides evidence that variations in food quality may plausibly be a micro-environmental mediating variable in food purchase and consumption and help partially explain neighbourhood differences in food consumption patterns.

Living in isolation - population structure, reproduction, and genetic variation of the endangered plant species Dianthus gratianopolitanus (Cheddar pink).

Science.gov (United States)

Putz, Christina M; Schmid, Christoph; Reisch, Christoph

2015-09-01

The endangered plant species Dianthus gratianopolitanus exhibits a highly fragmented distribution range comprising many isolated populations. Based upon this pattern of distribution, we selected a study region in Switzerland with a lower magnitude of isolation (Swiss Jura) and another study region in Germany with a higher degree of isolation (Franconian Jura). In each region, we chose ten populations to analyze population structure, reproduction, and genetic variation in a comparative approach. Therefore, we determined population density, cushion size, and cushion density to analyze population structure, investigated reproductive traits, including number of flowers, capsules, and germination rate, and analyzed amplified fragment length polymorphisms to study genetic variation. Population and cushion density were credibly higher in German than in Swiss populations, whereas reproductive traits and genetic variation within populations were similar in both study regions. However, genetic variation among populations and isolation by distance were stronger in Germany than in Switzerland. Generally, cushion size and density as well as flower and capsule production increased with population size and density, whereas genetic variation decreased with population density. In contrast to our assumptions, we observed denser populations and cushions in the region with the higher magnitude of isolation, whereas reproductive traits and genetic variation within populations were comparable in both regions. This corroborates the assumption that stronger isolation must not necessarily result in the loss of fitness and genetic variation. Furthermore, it supports our conclusion that the protection of strongly isolated populations contributes essentially to the conservation of a species' full evolutionary potential.

The Expanded FindCore Method for Identification of a Core Atom Set for Assessment of Protein Structure Prediction

Science.gov (United States)

Snyder, David A.; Grullon, Jennifer; Huang, Yuanpeng J.; Tejero, Roberto; Montelione, Gaetano T.

2014-01-01

Maximizing the scientific impact of NMR-based structure determination requires robust and statistically sound methods for assessing the precision of NMR-derived structures. In particular, a method to define a core atom set for calculating superimpositions and validating structure predictions is critical to the use of NMR-derived structures as targets in the CASP competition. FindCore (D.A. Snyder and G.T. Montelione PROTEINS 2005;59:673–686) is a superimposition independent method for identifying a core atom set, and partitioning that set into domains. However, as FindCore optimizes superimposition by sensitively excluding not-well-defined atoms, the FindCore core may not comprise all atoms suitable for use in certain applications of NMR structures, including the CASP assessment process. Adapting the FindCore approach to assess predicted models against experimental NMR structures in CASP10 required modification of the FindCore method. This paper describes conventions and a standard protocol to calculate an “Expanded FindCore” atom set suitable for validation and application in biological and biophysical contexts. A key application of the Expanded FindCore method is to identify a core set of atoms in the experimental NMR structure for which it makes sense to validate predicted protein structure models. We demonstrate the application of this Expanded FindCore method in characterizing well-defined regions of 18 NMR-derived CASP10 target structures. The Expanded FindCore protocol defines “expanded core atom sets” that match an expert’s intuition of which parts of the structure are sufficiently well-defined to use in assessing CASP model predictions. We also illustrate the impact of this analysis on the CASP GDT assessment scores. PMID:24327305

Vascular Structures of the Right Colon: Incidence and Variations with Their Clinical Implications.

Science.gov (United States)

Alsabilah, J; Kim, W R; Kim, N K

2017-06-01

There is a demand for a better understanding of the vascular structures around the right colonic area. Although right hemicolectomy with the recent concept of meticulous lymph node dissection is a standardized procedure for malignant diseases among most surgeons, variations in the actual anatomical vascular are not well understood. The aim of the present review was to present a detailed overview of the vascular variation pertinent to the surgery for right colon cancer. Medical literature was searched for the articles highlighting the vascular variation relevant to the right colon cancer surgery. Recently, there have been many detailed studies on applied surgical vascular anatomy based on cadaveric dissections, as well as radiological and intraoperative examinations to overcome misconceptions concerning the arterial supply and venous drainage to the right colon. Ileocolic artery and middle colic artery are consistently present in all patients arising from the superior mesenteric artery. Even though the ileocolic artery passes posterior to the superior mesenteric vein in most of the cases, in some cases courses anterior to the superior mesenteric artery. The right colic artery is inconsistently present ranging from 63% to 10% across different studies. Ileocolic vein and middle colic vein is always present, while the right colic vein is absent in 50% of patients. The gastrocolic trunk of Henle is present in 46%-100% patients across many studies with variation in the tributaries ranging from bipodal to tetrapodal. Commonly, it is found that the right colonic veins, including the right colic vein, middle colic vein, and superior right colic vein, share the confluence forming the gastrocolic trunk of Henle in a highly variable frequency and different forms. Understanding the incidence and variations of the vascular anatomy of right side colon is of crucial importance. Failure to recognize the variation during surgery can result in troublesome bleeding especially during

Effect of pressure variation on structural, elastic, mechanical, optoelectronic and thermodynamic properties of SrNaF3 fluoroperovskite

Science.gov (United States)

Erum, Nazia; Azhar Iqbal, Muhammad

2017-12-01

The effect of pressure variation on structural, electronic, elastic, mechanical, optical and thermodynamic characteristics of cubic SrNaF3 fluoroperovskite have been investigated by employing first-principles method within the framework of gradient approximation (GGA). For the total energy calculations, we have used the full-potential linearized augmented plane wave (FP-LAPW) method. Thermodynamic properties are computed in terms of quasi-harmonic Debye model. The pressure effects are determined in the range of 0-25 GPa, in which mechanical stability of SrNaF3 fluoroperovskite remains valid. A prominent decrease in lattice constant and bonds length is observed with the increase in pressure from 0 to 25 GPa. The effect of increase in pressure on band structure calculations with GGA and GGA plus Tran-Blaha modified Becke-Johnson (TB-mBJ) potential reveals a predominant characteristic associated with widening of bandgap. The influence of pressure on set of isotropic elastic parameters and their related properties are numerically estimated for SrNaF3 polycrystalline aggregate. Apart of linear dependence of elastic coefficients, transition from brittle to ductile behavior is observed as pressure is increased from 0 to 25 GPa. We have successfully obtained variation of lattice constant, volume expansion, bulk modulus, Debye temperature and specific heat capacities with pressure and temperature in the range of 0-25 GPa and 0-600 K. All the calculated optical properties such as the complex dielectric function ɛ(ω), optical conductivity σ(ω), energy loss function L(ω), absorption coefficient α(w), refractive index n(ω), reflectivity R(ω), and effective number of electrons n eff, via sum rules shift towards the higher energies under the application of pressure.

Structural-morphological variations in pseudo-barrier films of anode aluminium oxide under irradiation with high-energy particles

International Nuclear Information System (INIS)

Chernykh, M.A.; Belov, V.T.

1988-01-01

Comparative study of structural-morphological variations under electron beam effect in pseudo-barrier films of anode aluminium oxide, obtained in seven different solutions and proton or X-rays pre-irradiated to determine structure peculiarities of anode aluminium oxides, is presented. Such study is a matter of interest from the solid-phase transformation theory point of view and for anode aluminium films application under radiation. Stability increase of pseudo-barrier films of anode aluminium oxide to the effect of UEhMV-100 K microscope electron beam at standard modes of operation (75 kV) due to proton or X-rays irradiation is found. Difference in structural-monorphological variations obtained in different solutions of anode aluminium films under high-energy particles irradiation is determined. Strucural-phase microinhomogeneity of amorphous pseudo-barrier films of anode aluminium oxide and its influence on solid-phase transformations character under electron bean of maximal intensity are detected

Striking structural dynamism and nucleotide sequence variation of the transposon Galileo in the genome of Drosophila mojavensis.

Science.gov (United States)

Marzo, Mar; Bello, Xabier; Puig, Marta; Maside, Xulio; Ruiz, Alfredo

2013-02-04

Galileo is a transposable element responsible for the generation of three chromosomal inversions in natural populations of Drosophila buzzatii. Although the most characteristic feature of Galileo is the long internally-repetitive terminal inverted repeats (TIRs), which resemble the Drosophila Foldback element, its transposase-coding sequence has led to its classification as a member of the P-element superfamily (Class II, subclass 1, TIR order). Furthermore, Galileo has a wide distribution in the genus Drosophila, since it has been found in 6 of the 12 Drosophila sequenced genomes. Among these species, D. mojavensis, the one closest to D. buzzatii, presented the highest diversity in sequence and structure of Galileo elements. In the present work, we carried out a thorough search and annotation of all the Galileo copies present in the D. mojavensis sequenced genome. In our set of 170 Galileo copies we have detected 5 Galileo subfamilies (C, D, E, F, and X) with different structures ranging from nearly complete, to only 2 TIR or solo TIR copies. Finally, we have explored the structural and length variation of the Galileo copies that point out the relatively frequent rearrangements within and between Galileo elements. Different mechanisms responsible for these rearrangements are discussed. Although Galileo is a transposable element with an ancient history in the D. mojavensis genome, our data indicate a recent transpositional activity. Furthermore, the dynamism in sequence and structure, mainly affecting the TIRs, suggests an active exchange of sequences among the copies. This exchange could lead to new subfamilies of the transposon, which could be crucial for the long-term survival of the element in the genome.

Triple Hierarchical Variational Inequalities with Constraints of Mixed Equilibria, Variational Inequalities, Convex Minimization, and Hierarchical Fixed Point Problems

Directory of Open Access Journals (Sweden)

Lu-Chuan Ceng

2014-01-01

Full Text Available We introduce and analyze a hybrid iterative algorithm by virtue of Korpelevich's extragradient method, viscosity approximation method, hybrid steepest-descent method, and averaged mapping approach to the gradient-projection algorithm. It is proven that under appropriate assumptions, the proposed algorithm converges strongly to a common element of the fixed point set of infinitely many nonexpansive mappings, the solution set of finitely many generalized mixed equilibrium problems (GMEPs, the solution set of finitely many variational inequality problems (VIPs, the solution set of general system of variational inequalities (GSVI, and the set of minimizers of convex minimization problem (CMP, which is just a unique solution of a triple hierarchical variational inequality (THVI in a real Hilbert space. In addition, we also consider the application of the proposed algorithm to solve a hierarchical fixed point problem with constraints of finitely many GMEPs, finitely many VIPs, GSVI, and CMP. The results obtained in this paper improve and extend the corresponding results announced by many others.

The structure of a Cantor-like set with overlap

Energy Technology Data Exchange (ETDEWEB)

Dai Meifeng [Nonlinear Scientific Research Center, Faculty of Science, Jiangsu University, Zhenjiang, Jiangsu 212013 (China)] e-mail: daimf0225@163.com; Tian Lixin [Nonlinear Scientific Research Center, Faculty of Science, Jiangsu University, Zhenjiang, Jiangsu 212013 (China)] e-mail: tianlx@ujs.edu.cn

2005-10-01

In this paper, for the contracting similarities S{sub 0}(x)=x5, S{sub 1}(x)=x+{lambda}5, S{sub 2}(x)=x+25, S{sub 3}(x)=x+4-{lambda}5 and S{sub 4}(x)=x+45, where rational number {lambda}-bar [0,23], the Hausdorff dimension and the structure of E{sub {lambda}}, an invariant set with respect to S{sub 0}, S{sub 1}, S{sub 2}, S{sub 3}, S{sub 4} were studied and some new results were reported. Relation to El Naschie's quantum fractal is also discussed.

Effects of structured versus non-structured learning on achievement and attitudes of fifth graders in a public aquarium

Science.gov (United States)

Kafka, Merryl Audrey

The investigator analyzed the main effect of a structured-learning experience in an informal setting, as well as interactions between the students' learning-style variations toward the element of structure and the imposed instructional conditions. The subjects consisted of 170 students enrolled in two public schools located in Brooklyn, New York. The students were predominantly a White multi-ethnic population consisting of 118 Caucasians, 25 Hispanics, 24 Asians, and 3 African-Americans. Three randomly assigned classes (n = 81) were provided trip sheets, which directed students on how to learn new information with written questions and directives. Three randomly assigned non-structured classes (n = 89) experienced the same exhibit in a free-form manner. Science-based criterion-referenced pre- and posttests were administered, in addition to Learning Style Inventories (Dunn, Dunn, & Price, 1996) and a modified Semantic Differential Scale (Pizzo, 1981), which was used to measure attitudinal levels. The non-structured group had access to similar content information in the form of exhibit graphics, but apparently they chose not to read it as carefully or engage in the information-seeking process as intensely as the students equipped with trip sheets. Analysis of covariance (ANCOVA) indicated that a structured-learning experience produced significantly higher science-achievement test scores than in a non-structured-learning experience (p = .0001). In addition, there was no single learning-style variation (preference, aversion, or no preference) to structure that produced significantly higher gains than another. Furthermore, attitudinal scores were not significantly different between structured and non-structured groups, as well as among homogeneous subsets of students with learning-style variations that matched, mismatched, or indicated no-preferenced positions on the element of structure. Hence, a moderate amount of structure resulted in academic gains without

1H and 15N NMR assignment and solution structure of the SH3 domain of spectrin: Comparison of unrefined and refined structure sets with the crystal structure

International Nuclear Information System (INIS)

Blanco, Francisco J.; Ortiz, Angel R.; Serrano, Luis

1997-01-01

The assignment of the 1 H and 15 Nnuclear magnetic resonance spectra of the Src-homology region 3 domain of chicken brain α-spectrin has been obtained. A set of solution structures has been determined from distance and dihedral angle restraints,which provide a reasonable representation of the protein structure in solution, as evaluated by a principal component analysis of the global pairwise root-mean-square deviation (rmsd) in a large set of structures consisting of the refined and unrefined solution structures and the crystal structure. The solution structure is well defined, with a lower degree of convergence between the structures in the loop regions than in the secondary structure elements. The average pairwise rmsd between the 15 refined solution structures is 0.71 ± 0.13 A for the backbone atoms and 1.43 ± 0.14 A for all heavy atoms. The solution structure is basically the same as the crystal structure. The average rmsd between the 15 refined solution structures and the crystal structure is 0.76 A for the backbone atoms and 1.45 ± 0.09 A for all heavy atoms. There are, however, small differences probably caused by intermolecular contacts in the crystal structure

Biogeographical Variation and Population Genetic Structure of Sporisorium scitamineum in Mainland China: Insights from ISSR and SP-SRAP Markers

Directory of Open Access Journals (Sweden)

Liping Xu

2014-01-01

Full Text Available A total of 100 Sporisorium scitamineum isolates were investigated by inter simple sequence repeat (ISSR and single primer-sequence related amplified polymorphism (SP-SRAP markers. These isolates were clearly assorted into three distinct clusters regardless of method used: either cluster analysis or by principal component analysis (PCA of the ISSR, SP-SRAP, or ISSR + SP-SRAP data set. The total gene diversity (Ht and gene diversity between subpopulations (Hs were estimated to be 0.34 to 0.38 and 0.22 to 0.29, respectively, by analyzing separately the ISSR and SP-SRAP data sets, and to be 0.26–0.36 by analyzing ISSR + SP-SRAP data set. The gene diversity attributable to differentiation among populations (Gst was estimated to be 0.35 and 0.22, and the gene flow (Nm was 0.94 and 1.78, respectively, when analyzing separately ISSR and SP-SRAP data set, and was 0.27 and 1.33, respectively, when analyzing ISSR + SP-SRAP data set. Our study showed that there is considerable genetic variation in the analyzed 100 isolates, and the environmental heterogeneity has played an important role for this observed high degree of variation. The genetic differentiation of sugarcane smut fungus depends to a large extent on the heterogeneity of their habitats and is the result of long-term adaptations of pathogens to their ecological environments.

Mapping genetic variations to three-dimensional protein structures to enhance variant interpretation: a proposed framework.

Science.gov (United States)

Glusman, Gustavo; Rose, Peter W; Prlić, Andreas; Dougherty, Jennifer; Duarte, José M; Hoffman, Andrew S; Barton, Geoffrey J; Bendixen, Emøke; Bergquist, Timothy; Bock, Christian; Brunk, Elizabeth; Buljan, Marija; Burley, Stephen K; Cai, Binghuang; Carter, Hannah; Gao, JianJiong; Godzik, Adam; Heuer, Michael; Hicks, Michael; Hrabe, Thomas; Karchin, Rachel; Leman, Julia Koehler; Lane, Lydie; Masica, David L; Mooney, Sean D; Moult, John; Omenn, Gilbert S; Pearl, Frances; Pejaver, Vikas; Reynolds, Sheila M; Rokem, Ariel; Schwede, Torsten; Song, Sicheng; Tilgner, Hagen; Valasatava, Yana; Zhang, Yang; Deutsch, Eric W

2017-12-18

The translation of personal genomics to precision medicine depends on the accurate interpretation of the multitude of genetic variants observed for each individual. However, even when genetic variants are predicted to modify a protein, their functional implications may be unclear. Many diseases are caused by genetic variants affecting important protein features, such as enzyme active sites or interaction interfaces. The scientific community has catalogued millions of genetic variants in genomic databases and thousands of protein structures in the Protein Data Bank. Mapping mutations onto three-dimensional (3D) structures enables atomic-level analyses of protein positions that may be important for the stability or formation of interactions; these may explain the effect of mutations and in some cases even open a path for targeted drug development. To accelerate progress in the integration of these data types, we held a two-day Gene Variation to 3D (GVto3D) workshop to report on the latest advances and to discuss unmet needs. The overarching goal of the workshop was to address the question: what can be done together as a community to advance the integration of genetic variants and 3D protein structures that could not be done by a single investigator or laboratory? Here we describe the workshop outcomes, review the state of the field, and propose the development of a framework with which to promote progress in this arena. The framework will include a set of standard formats, common ontologies, a common application programming interface to enable interoperation of the resources, and a Tool Registry to make it easy to find and apply the tools to specific analysis problems. Interoperability will enable integration of diverse data sources and tools and collaborative development of variant effect prediction methods.

Hybrid Steepest-Descent Methods for Triple Hierarchical Variational Inequalities

Directory of Open Access Journals (Sweden)

L. C. Ceng

2015-01-01

Full Text Available We introduce and analyze a relaxed iterative algorithm by combining Korpelevich’s extragradient method, hybrid steepest-descent method, and Mann’s iteration method. We prove that, under appropriate assumptions, the proposed algorithm converges strongly to a common element of the fixed point set of infinitely many nonexpansive mappings, the solution set of finitely many generalized mixed equilibrium problems (GMEPs, the solution set of finitely many variational inclusions, and the solution set of general system of variational inequalities (GSVI, which is just a unique solution of a triple hierarchical variational inequality (THVI in a real Hilbert space. In addition, we also consider the application of the proposed algorithm for solving a hierarchical variational inequality problem with constraints of finitely many GMEPs, finitely many variational inclusions, and the GSVI. The results obtained in this paper improve and extend the corresponding results announced by many others.

Along-dip variations of structural style in the Somali Basin deep-water fold and thrust belt (East Africa)

Science.gov (United States)

Cruciani, Francesco; Rinaldo Barchi, Massimiliano

2014-05-01

Continental passive margins are place of extended slope-failure phenomena, which can lead to the formation of gravity-driven deep-water fold and thrust belts (DW-FTBs), in regions where no far-field compressional stress is active. These giant geological features, which are confined to the sedimentary section, consist of extensional-compressional linked systems detached over a common décollement, generally salt or shales. The continental passive margin of northern Kenya and southern Somalia is an excellent and relatively unexplored site for recognizing and understanding the DW-FTBs originated over a regional shale décollement. In this study we have interpreted a 2D seismic data-set of the 1980s, hosted by Marine Geoscience Data System at Lamont-Doherty Earth Observatory of Columbia University (http://www.marine-geo.org), and recently reprocessed by ENI, in order to investigate the structural style of a DW-FTB developed offshore of northern Kenya and southern Somalia (Somali Basin). This region records the oldest sedimentary section of the Indian Ocean since the breakup of Gondwana began in the Middle-Lower Jurassic separating Madagascar from Africa. From the Upper Cretaceous to at least the Lower Miocene, the margin has been characterized by gravitational collapse leading to the formation of a DW-FTB extending more than 400 km along-strike. The northern portion of the DW-FTB is about 150 km wide, whilst in the southern portion is few tens of km wide. We analysed the northern portion along a regional seismic section. Our study represents the first detailed structural interpretation of this DW-FTB since its discovery in the 1980s. The good quality of the available reprocessed seismic data has allowed us to identify remarkable along-dip variations in the structural style. The basal detachment constantly deepens landward, in agreement with a prevailing gravity-spreading deformation process (as in the case of the Niger Delta). On the seismic data are not visible, as

Variation of solvent scattering-length density small-angle neutron scattering as a means of determining structure of composite materials

International Nuclear Information System (INIS)

Hjelm, R.P.; Wampler, W.; Gerspacher, M.

1994-01-01

As part of our work on the, structure of composite materials we have been exploring the use of small-angle neutron scattering using the method of contrast variation to dissect the component form, structure and distribution. This approach has resulted in a new look at very old problem reinforcement of elastomers by carbon black. Using this approach we studied an experimental high surface area (HSA) carbon black and a gel of ''HSA-bound'' rubber in cyclohexane/deuterocyclohexane mixtures. HSA in cyclohexane is found to be short rodlike particle aggregates. The aggregates have a shell-core structure with a high density graphitic outer shell and an inner core of lower density amorphous carbon. The core is continuous throughout the carbon black aggregate, making the aggregate a stiff, integral unit. Contrast variation of swollen composite gels shows that there are two length scales in the gel structure. Above 10 Angstrom, scattering from carbon black predominates, and below 10 Angstrom the scattering is from both carbon black and the elastomer. The HSA in the composite is completely embedded in polyisoprene. An estimate of the carbon black structure factor shows strong exclusion of neighboring aggregates, probably from excluded volume effects. The surface structure of the carbon black is unaltered by the interactions with elastomer and appears smooth over length scales above about 10 Angstrom. These results show that contrast variation can provide information on composite structure that is not available by other means. This information relates to the reinforcement mechanism of elastomers by carbon blacks

SV-AUTOPILOT: optimized, automated construction of structural variation discovery and benchmarking pipelines.

Science.gov (United States)

Leung, Wai Yi; Marschall, Tobias; Paudel, Yogesh; Falquet, Laurent; Mei, Hailiang; Schönhuth, Alexander; Maoz Moss, Tiffanie Yael

2015-03-25

Many tools exist to predict structural variants (SVs), utilizing a variety of algorithms. However, they have largely been developed and tested on human germline or somatic (e.g. cancer) variation. It seems appropriate to exploit this wealth of technology available for humans also for other species. Objectives of this work included: a) Creating an automated, standardized pipeline for SV prediction. b) Identifying the best tool(s) for SV prediction through benchmarking. c) Providing a statistically sound method for merging SV calls. The SV-AUTOPILOT meta-tool platform is an automated pipeline for standardization of SV prediction and SV tool development in paired-end next-generation sequencing (NGS) analysis. SV-AUTOPILOT comes in the form of a virtual machine, which includes all datasets, tools and algorithms presented here. The virtual machine easily allows one to add, replace and update genomes, SV callers and post-processing routines and therefore provides an easy, out-of-the-box environment for complex SV discovery tasks. SV-AUTOPILOT was used to make a direct comparison between 7 popular SV tools on the Arabidopsis thaliana genome using the Landsberg (Ler) ecotype as a standardized dataset. Recall and precision measurements suggest that Pindel and Clever were the most adaptable to this dataset across all size ranges while Delly performed well for SVs larger than 250 nucleotides. A novel, statistically-sound merging process, which can control the false discovery rate, reduced the false positive rate on the Arabidopsis benchmark dataset used here by >60%. SV-AUTOPILOT provides a meta-tool platform for future SV tool development and the benchmarking of tools on other genomes using a standardized pipeline. It optimizes detection of SVs in non-human genomes using statistically robust merging. The benchmarking in this study has demonstrated the power of 7 different SV tools for analyzing different size classes and types of structural variants. The optional merge

Prostate Contouring Variation: Can It Be Fixed?

International Nuclear Information System (INIS)

Khoo, Eric L.H.; Schick, Karlissa; Plank, Ashley W.; Poulsen, Michael; Wong, Winnie W.G.; Middleton, Mark; Martin, Jarad M.

2012-01-01

Purpose: To assess whether an education program on CT and MRI prostate anatomy would reduce inter- and intraobserver prostate contouring variation among experienced radiation oncologists. Methods and Materials: Three patient CT and MRI datasets were selected. Five radiation oncologists contoured the prostate for each patient on CT first, then MRI, and again between 2 and 4 weeks later. Three education sessions were then conducted. The same contouring process was then repeated with the same datasets and oncologists. The observer variation was assessed according to changes in the ratio of the encompassing volume to intersecting volume (volume ratio [VR]), across sets of target volumes. Results: For interobserver variation, there was a 15% reduction in mean VR with CT, from 2.74 to 2.33, and a 40% reduction in mean VR with MRI, from 2.38 to 1.41 after education. A similar trend was found for intraobserver variation, with a mean VR reduction for CT and MRI of 9% (from 1.51 to 1.38) and 16% (from 1.37 to 1.15), respectively. Conclusion: A well-structured education program has reduced both inter- and intraobserver prostate contouring variations. The impact was greater on MRI than on CT. With the ongoing incorporation of new technologies into routine practice, education programs for target contouring should be incorporated as part of the continuing medical education of radiation oncologists.

Geographical and organisational variation in the structure of primary care services: implications for study design.

Science.gov (United States)

Adams, Geoffrey; Gulliford, Martin; Ukoumunne, Obioha; Chinn, Susan; Campbell, Michael

2003-04-01

To evaluate the extent to which structural variation between English general practices is accounted for at higher organisational levels in the National Health Service (NHS). We analysed data for 11 structural characteristics of all general practices in England. These included characteristics of general practitioners (GPs), the practice list and the services provided by practices. A four-level random effects model was used for analysis and components of variance were estimated at the levels of practice, primary care group (PCG), health authority and region. The proportion of single-handed practices ranged from 0% to 74% at PCG level and from 14% to 43% in different regions. The proportion of practices providing diabetes services ranged from 0% to 100% at PCG level and from 71% to 96% in different regions. The list size per GP ranged from 1314 to 2704 patients per GP at PCG level and from 1721 to 2225 at regional level. Across the 11 variables analysed, components of variance at general practice level accounted for between 43% and 95% of the total variance. The PCG level accounted for between 1% and 29%, the health authority level for between 2% and 15% and the regional level for between 0% and 13% of the total variance. Adjusting for an index of deprivation and the supply of GPs gave a median 8% decrease in the sum of variance components. Geographical and organisational variation in the structure of primary care services should be considered in designing studies in health systems such as the English NHS. Stratified designs may be used to increase study efficiency, but variation between areas may sometimes compromise generalisability.

Modeling the blockage of Lg waves from 3-D variations in crustal structure

Science.gov (United States)

Sanborn, Christopher J.; Cormier, Vernon F.

2018-05-01

Comprised of S waves trapped in Earth's crust, the high frequency (2-10 Hz) Lg wave is important to discriminating earthquakes from explosions by comparing its amplitude and waveform to those of Pg and Pn waves. Lateral variations in crustal structure, including variations in crustal thickness, intrinsic attenuation, and scattering, affect the efficiency of Lg propagation and its consistency as a source discriminant at regional (200-1500 km) distances. To investigate the effects of laterally varying Earth structure on the efficiency of propagation of Lg and Pg, we apply a radiative transport algorithm to model complete, high-frequency (2-4 Hz), regional coda envelopes. The algorithm propagates packets of energy with ray theory through large-scale 3-D structure, and includes stochastic effects of multiple-scattering by small-scale heterogeneities within the large-scale structure. Source-radiation patterns are described by moment tensors. Seismograms of explosion and earthquake sources are synthesized in canonical models to predict effects on waveforms of paths crossing regions of crustal thinning (pull-apart basins and ocean/continent transitions) and thickening (collisional mountain belts), For paths crossing crustal thinning regions, Lg is amplified at receivers within the thinned region but strongly disrupted and attenuated at receivers beyond the thinned region. For paths crossing regions of crustal thickening, Lg amplitude is attenuated at receivers within the thickened region, but experiences little or no reduction in amplitude at receivers beyond the thickened region. The length of the Lg propagation within a thickened region and the complexity of over- and under-thrust crustal layers, can produce localized zones of Lg amplification or attenuation. Regions of intense scattering within laterally homogeneous models of the crust increase Lg attenuation but do not disrupt its coda shape.

Defining the diverse spectrum of inversions, complex structural variation, and chromothripsis in the morbid human genome

NARCIS (Netherlands)

Collins, Ryan L; Brand, Harrison; Redin, Claire E.; Hanscom, Carrie; Antolik, Caroline; Stone, Matthew R; Glessner, Joseph T.; Mason, Tamara; Pregno, Giulia; Dorrani, Naghmeh; Mandrile, Giorgia; Giachino, Daniela; Perrin, Danielle; Walsh, Cole; Cipicchio, Michelle; Costello, Maura; Stortchevoi, Alexei; An, Joon Yong; Currall, Benjamin B; Seabra, Catarina M; Ragavendran, Ashok; Margolin, Lauren; Martinez-Agosto, Julian A.; Lucente, Diane; Levy, Brynn; Sanders, Jan-Stephan; Wapner, Ronald J.; Quintero-Rivera, Fabiola; Kloosterman, Wigard; Talkowski, Michael E.

2017-01-01

Background: Structural variation (SV) influences genome organization and contributes to human disease. However, the complete mutational spectrum of SV has not been routinely captured in disease association studies. Results: We sequenced 689 participants with autism spectrum disorder (ASD) and other

Genetic and ontogenetic variation in an endangered tree structures dependent arthropod and fungal communities.

Directory of Open Access Journals (Sweden)

Benjamin J Gosney

Full Text Available Plant genetic and ontogenetic variation can significantly impact dependent fungal and arthropod communities. However, little is known of the relative importance of these extended genetic and ontogenetic effects within a species. Using a common garden trial, we compared the dependent arthropod and fungal community on 222 progeny from two highly differentiated populations of the endangered heteroblastic tree species, Eucalyptus morrisbyi. We assessed arthropod and fungal communities on both juvenile and adult foliage. The community variation was related to previous levels of marsupial browsing, as well as the variation in the physicochemical properties of leaves using near-infrared spectroscopy. We found highly significant differences in community composition, abundance and diversity parameters between eucalypt source populations in the common garden, and these were comparable to differences between the distinctive juvenile and adult foliage. The physicochemical properties assessed accounted for a significant percentage of the community variation but did not explain fully the community differences between populations and foliage types. Similarly, while differences in population susceptibility to a major marsupial herbivore may result in diffuse genetic effects on the dependent community, this still did not account for the large genetic-based differences in dependent communities between populations. Our results emphasize the importance of maintaining the populations of this rare species as separate management units, as not only are the populations highly genetically structured, this variation may alter the trajectory of biotic colonization of conservation plantings.

Variations in the Contouring of Organs at Risk: Test Case From a Patient With Oropharyngeal Cancer

Energy Technology Data Exchange (ETDEWEB)

Nelms, Benjamin E., E-mail: alpha@canislupusllc.com [Canis Lupus LLC, Merrimac, WI (United States); Tome, Wolfgang A. [Department of Human Oncology, University of Wisconsin, Madison, WI (United States); Robinson, Greg [Radiation Oncology Resources, Goshen, IN (United States); Wheeler, James [Department of Radiation Oncology, Goshen Health System Goshen, IN (United States)

2012-01-01

Purpose: Anatomy contouring is critical in radiation therapy. Inaccuracy and variation in defining critical volumes will affect everything downstream: treatment planning, dose-volume histogram analysis, and contour-based visual guidance used in image-guided radiation therapy. This study quantified: (1) variation in the contouring of organs at risk (OAR) in a clinical test case and (2) corresponding effects on dosimetric metrics of highly conformal plans. Methods and Materials: A common CT data set with predefined targets from a patient with oropharyngeal cancer was provided to a population of clinics, which were asked to (1) contour OARs and (2) design an intensity-modulated radiation therapy plan. Thirty-two acceptable plans were submitted as DICOM RT data sets, each generated by a different clinical team. Using those data sets, we quantified: (1) the OAR contouring variation and (2) the impact this variation has on dosimetric metrics. New technologies were employed, including a software tool to quantify three-dimensional structure comparisons. Results: There was significant interclinician variation in OAR contouring. The degree of variation is organ-dependent. We found substantial dose differences resulting strictly from contouring variation (differences ranging from -289% to 56% for mean OAR dose; -22% to 35% for maximum dose). However, there appears to be a threshold in the OAR comparison metric beyond which the dose differences stabilize. Conclusions: The effects of interclinician variation in contouring organs-at-risk in the head and neck can be large and are organ-specific. Physicians need to be aware of the effect that variation in OAR contouring can play on the final treatment plan and not restrict their focus only to the target volumes.

3D OCT imaging in clinical settings: toward quantitative measurements of retinal structures

Science.gov (United States)

Zawadzki, Robert J.; Fuller, Alfred R.; Zhao, Mingtao; Wiley, David F.; Choi, Stacey S.; Bower, Bradley A.; Hamann, Bernd; Izatt, Joseph A.; Werner, John S.

2006-02-01

The acquisition speed of current FD-OCT (Fourier Domain - Optical Coherence Tomography) instruments allows rapid screening of three-dimensional (3D) volumes of human retinas in clinical settings. To take advantage of this ability requires software used by physicians to be capable of displaying and accessing volumetric data as well as supporting post processing in order to access important quantitative information such as thickness maps and segmented volumes. We describe our clinical FD-OCT system used to acquire 3D data from the human retina over the macula and optic nerve head. B-scans are registered to remove motion artifacts and post-processed with customized 3D visualization and analysis software. Our analysis software includes standard 3D visualization techniques along with a machine learning support vector machine (SVM) algorithm that allows a user to semi-automatically segment different retinal structures and layers. Our program makes possible measurements of the retinal layer thickness as well as volumes of structures of interest, despite the presence of noise and structural deformations associated with retinal pathology. Our software has been tested successfully in clinical settings for its efficacy in assessing 3D retinal structures in healthy as well as diseased cases. Our tool facilitates diagnosis and treatment monitoring of retinal diseases.

Atmospheric Structure and Diurnal Variations at Low Altitudes in the Martian Tropics

Science.gov (United States)

Hinson, David P.; Spiga, A.; Lewis, S.; Tellmann, S.; Pätzold, M.; Asmar, S.; Häusler, B.

2013-10-01

We are using radio occultation measurements from Mars Express, Mars Reconnaissance Orbiter, and Mars Global Surveyor to characterize the diurnal cycle in the lowest scale height above the surface. We focus on northern spring and summer, using observations from 4 Martian years at local times of 4-5 and 15-17 h. We supplement the observations with results obtained from large-eddy simulations and through data assimilation by the UK spectral version of the LMD Mars Global Circulation Model. We previously investigated the depth of the daytime convective boundary layer (CBL) and its variations with surface elevation and surface properties. We are now examining unusual aspects of the temperature structure observed at night. Most important, predawn profiles in the Tharsis region contain an unexpected layer of neutral static stability at pressures of 200-300 Pa with a depth of 4-5 km. The mixed layer is bounded above by a midlevel temperature inversion and below by another strong inversion adjacent to the surface. The narrow temperature minimum at the base of the midlevel inversion suggests the presence of a water ice cloud layer, with the further implication that radiative cooling at cloud level can induce convective activity at lower altitudes. Conversely, nighttime profiles in Amazonis show no sign of a midlevel inversion or a detached mixed layer. These regional variations in the nighttime temperature structure appear to arise in part from large-scale variations in topography, which have several notable effects. First, the CBL is much deeper in the Tharsis region than in Amazonis, owing to a roughly 6-km difference in surface elevation. Second, large-eddy simulations show that daytime convection is not only deeper above Tharsis but also considerably more intense than it is in Amazonis. Finally, the daytime surface temperatures are comparable in the two regions, so that Tharsis acts as an elevated heat source throughout the CBL. These topographic effects are expected to

Implicit leadership theories in applied settings: factor structure, generalizability, and stability over time.

Science.gov (United States)

Epitropaki, Olga; Martin, Robin

2004-04-01

The present empirical investigation had a 3-fold purpose: (a) to cross-validate L. R. Offermann, J. K. Kennedy, and P. W. Wirtz's (1994) scale of Implicit Leadership Theories (ILTs) in several organizational settings and to further provide a shorter scale of ILTs in organizations; (b) to assess the generalizability of ILTs across different employee groups, and (c) to evaluate ILTs' change over time. Two independent samples were used for the scale validation (N1 = 500 and N2 = 439). A 6-factor structure (Sensitivity, Intelligence, Dedication, Dynamism, Tyranny, and Masculinity) was found to most accurately represent ELTs in organizational settings. Regarding the generalizability of ILTs, although the 6-factor structure was consistent across different employee groups, there was only partial support for total factorial invariance. Finally, evaluation of gamma, beta, and alpha change provided support for ILTs' stability over time.

Basin-wide variations in Amazon forest structure and function are mediated by both soils and climate

Science.gov (United States)

Quesada, C. A.; Phillips, O. L.; Schwarz, M.; Czimczik, C. I.; Baker, T. R.; Patiño, S.; Fyllas, N. M.; Hodnett, M. G.; Herrera, R.; Almeida, S.; Alvarez Dávila, E.; Arneth, A.; Arroyo, L.; Chao, K. J.; Dezzeo, N.; Erwin, T.; di Fiore, A.; Higuchi, N.; Honorio Coronado, E.; Jimenez, E. M.; Killeen, T.; Lezama, A. T.; Lloyd, G.; López-González, G.; Luizão, F. J.; Malhi, Y.; Monteagudo, A.; Neill, D. A.; Núñez Vargas, P.; Paiva, R.; Peacock, J.; Peñuela, M. C.; Peña Cruz, A.; Pitman, N.; Priante Filho, N.; Prieto, A.; Ramírez, H.; Rudas, A.; Salomão, R.; Santos, A. J. B.; Schmerler, J.; Silva, N.; Silveira, M.; Vásquez, R.; Vieira, I.; Terborgh, J.; Lloyd, J.

2012-06-01

Forest structure and dynamics vary across the Amazon Basin in an east-west gradient coincident with variations in soil fertility and geology. This has resulted in the hypothesis that soil fertility may play an important role in explaining Basin-wide variations in forest biomass, growth and stem turnover rates. Soil samples were collected in a total of 59 different forest plots across the Amazon Basin and analysed for exchangeable cations, carbon, nitrogen and pH, with several phosphorus fractions of likely different plant availability also quantified. Physical properties were additionally examined and an index of soil physical quality developed. Bivariate relationships of soil and climatic properties with above-ground wood productivity, stand-level tree turnover rates, above-ground wood biomass and wood density were first examined with multivariate regression models then applied. Both forms of analysis were undertaken with and without considerations regarding the underlying spatial structure of the dataset. Despite the presence of autocorrelated spatial structures complicating many analyses, forest structure and dynamics were found to be strongly and quantitatively related to edaphic as well as climatic conditions. Basin-wide differences in stand-level turnover rates are mostly influenced by soil physical properties with variations in rates of coarse wood production mostly related to soil phosphorus status. Total soil P was a better predictor of wood production rates than any of the fractionated organic- or inorganic-P pools. This suggests that it is not only the immediately available P forms, but probably the entire soil phosphorus pool that is interacting with forest growth on longer timescales. A role for soil potassium in modulating Amazon forest dynamics through its effects on stand-level wood density was also detected. Taking this into account, otherwise enigmatic variations in stand-level biomass across the Basin were then accounted for through the

Spatial variations in food web structures with alternative stable states: evidence from stable isotope analysis in a large eutrophic lake

Science.gov (United States)

Li, Yunkai; Zhang, Yuying; Xu, Jun; Zhang, Shuo

2018-03-01

Food web structures are well known to vary widely among ecosystems. Moreover, many food web studies of lakes have generally attempted to characterize the overall food web structure and have largely ignored internal spatial and environmental variations. In this study, we hypothesize that there is a high degree of spatial heterogeneity within an ecosystem and such heterogeneity may lead to strong variations in environmental conditions and resource availability, in turn resulting in different trophic pathways. Stable carbon and nitrogen isotopes were employed for the whole food web to describe the structure of the food web in different sub-basins within Taihu Lake. This lake is a large eutrophic freshwater lake that has been intensively managed and highly influenced by human activities for more than 50 years. The results show significant isotopic differences between basins with different environmental characteristics. Such differences likely result from isotopic baseline differences combining with a shift in food web structure. Both are related to local spatial heterogeneity in nutrient loading in waters. Such variation should be explicitly considered in future food web studies and ecosystem-based management in this lake ecosystem.

Spatial variations in food web structures with alternative stable states: evidence from stable isotope analysis in a large eutrophic lake

Science.gov (United States)

Li, Yunkai; Zhang, Yuying; Xu, Jun; Zhang, Shuo

2017-05-01

Food web structures are well known to vary widely among ecosystems. Moreover, many food web studies of lakes have generally attempted to characterize the overall food web structure and have largely ignored internal spatial and environmental variations. In this study, we hypothesize that there is a high degree of spatial heterogeneity within an ecosystem and such heterogeneity may lead to strong variations in environmental conditions and resource availability, in turn resulting in different trophic pathways. Stable carbon and nitrogen isotopes were employed for the whole food web to describe the structure of the food web in different sub-basins within Taihu Lake. This lake is a large eutrophic freshwater lake that has been intensively managed and highly influenced by human activities for more than 50 years. The results show significant isotopic differences between basins with different environmental characteristics. Such differences likely result from isotopic baseline differences combining with a shift in food web structure. Both are related to local spatial heterogeneity in nutrient loading in waters. Such variation should be explicitly considered in future food web studies and ecosystem-based management in this lake ecosystem.

Fast-slow continuum and reproductive strategies structure plant life-history variation worldwide

DEFF Research Database (Denmark)

Salguero-Gómez, Roberto; Jones, Owen R; Jongejans, Eelke

2016-01-01

The identification of patterns in life-history strategies across the tree of life is essential to our prediction of population persistence, extinction, and diversification. Plants exhibit a wide range of patterns of longevity, growth, and reproduction, but the general determinants of this enormous...... variation in life history are poorly understood. We use demographic data from 418 plant species in the wild, from annual herbs to supercentennial trees, to examine how growth form, habitat, and phylogenetic relationships structure plant life histories and to develop a framework to predict population...

Population genetic variation in the tree fern Alsophila spinulosa (Cyatheaceae): effects of reproductive strategy.

Science.gov (United States)

Wang, Ting; Su, Yingjuan; Li, Yuan

2012-01-01

Essentially all ferns can perform both sexual and asexual reproduction. Their populations represent suitable study objects to test the population genetic effects of different reproductive systems. Using the diploid homosporous fern Alsophila spinulosa as an example species, the main purpose of this study was to assess the relative impact of sexual and asexual reproduction on the level and structure of population genetic variation. Inter-simple sequence repeats analysis was conducted on 140 individuals collected from seven populations (HSG, LCH, BPC, MPG, GX, LD, and ZHG) in China. Seventy-four polymorphic bands discriminated a total of 127 multilocus genotypes. Character compatibility analysis revealed that 50.0 to 70.0% of the genotypes had to be deleted in order to obtain a tree-like structure in the data set from populations HSG, LCH, MPG, BPC, GX, and LD; and there was a gradual decrease of conflict in the data set when genotypes with the highest incompatibility counts were successively deleted. In contrast, in population ZHG, only 33.3% of genotypes had to be removed to achieve complete compatibility in the data set, which showed a sharp decline in incompatibility upon the deletion of those genotypes. All populations examined possessed similar levels of genetic variation. Population ZHG was not found to be more differentiated than the other populations. Sexual recombination is the predominant source of genetic variation in most of the examined populations of A. spinulosa. However, somatic mutation contributes most to the genetic variation in population ZHG. This change of the primary mode of reproduction does not cause a significant difference in the population genetic composition. Character compatibility analysis represents an effective approach to separate the role of sexual and asexual components in shaping the genetic pattern of fern populations.

Population genetic variation in the tree fern Alsophila spinulosa (Cyatheaceae: effects of reproductive strategy.

Directory of Open Access Journals (Sweden)

Ting Wang

Full Text Available BACKGROUND: Essentially all ferns can perform both sexual and asexual reproduction. Their populations represent suitable study objects to test the population genetic effects of different reproductive systems. Using the diploid homosporous fern Alsophila spinulosa as an example species, the main purpose of this study was to assess the relative impact of sexual and asexual reproduction on the level and structure of population genetic variation. METHODOLOGY/PRINCIPAL FINDINGS: Inter-simple sequence repeats analysis was conducted on 140 individuals collected from seven populations (HSG, LCH, BPC, MPG, GX, LD, and ZHG in China. Seventy-four polymorphic bands discriminated a total of 127 multilocus genotypes. Character compatibility analysis revealed that 50.0 to 70.0% of the genotypes had to be deleted in order to obtain a tree-like structure in the data set from populations HSG, LCH, MPG, BPC, GX, and LD; and there was a gradual decrease of conflict in the data set when genotypes with the highest incompatibility counts were successively deleted. In contrast, in population ZHG, only 33.3% of genotypes had to be removed to achieve complete compatibility in the data set, which showed a sharp decline in incompatibility upon the deletion of those genotypes. All populations examined possessed similar levels of genetic variation. Population ZHG was not found to be more differentiated than the other populations. CONCLUSIONS/SIGNIFICANCE: Sexual recombination is the predominant source of genetic variation in most of the examined populations of A. spinulosa. However, somatic mutation contributes most to the genetic variation in population ZHG. This change of the primary mode of reproduction does not cause a significant difference in the population genetic composition. Character compatibility analysis represents an effective approach to separate the role of sexual and asexual components in shaping the genetic pattern of fern populations.

Period variations in pulsating X-ray sources. I. Accretion flow parameters and neutron star structure from timing observations

International Nuclear Information System (INIS)

Lamb, F.K.; Pines, D.; Shaham, J.

1978-01-01

We show that valuable information about both accretion flows and neutron star structure can be obtained from X-ray timing observations of period variations in pulsating sources. Such variations can result from variations in the accretion flow, or from internal torque variations, associated with oscillations of the fluid core or the unpinning of vortices in the inner crust. We develop a statistical description of torque variations in terms of noise processes, indicate how the applicability of such a description may be tested observationally, and show how it may be used to determine from observation both the properties of accretion flows and the internal structure of neutron stars, including the relative inertial moments of the crust and superfluid neutron core, the crust-core coupling time, and the frequencies of any low-frequency internal collective modes. Particular attention is paid to the physical origin of spin-down episodes; it is shown that usyc episodes may result either from external torque reversals or from internal torque variations.With the aid of the statistical description, the response of the star to torque fluctuations is calculated for three stellar models: (i) a completely rigid star; (ii) a two-component star; and (iii) a two-component star with a finite-frequency internal mode, such as the Tkachenko mode of a rotating neutron superfluid. Our calculations show that fluctuating torques could account for the period the period variations and spin-down episodes observed in Her X-1 and Cen X-3, including the large spin-down event observed in the latter source during 1972 September-October. The torque noise strengths inferred from current timing observations using the simple two-component models are shown to be consistent with those to be expected from fluctuations in accretion flows onto magnetic neutron stars

Generalized rough sets hybrid structure and applications

CERN Document Server

Mukherjee, Anjan

2015-01-01

The book introduces the concept of “generalized interval valued intuitionistic fuzzy soft sets”. It presents the basic properties of these sets and also, investigates an application of generalized interval valued intuitionistic fuzzy soft sets in decision making with respect to interval of degree of preference. The concept of “interval valued intuitionistic fuzzy soft rough sets” is discussed and interval valued intuitionistic fuzzy soft rough set based multi criteria group decision making scheme is presented, which refines the primary evaluation of the whole expert group and enables us to select the optimal object in a most reliable manner. The book also details concept of interval valued intuitionistic fuzzy sets of type 2. It presents the basic properties of these sets. The book also introduces the concept of “interval valued intuitionistic fuzzy soft topological space (IVIFS topological space)” together with intuitionistic fuzzy soft open sets (IVIFS open sets) and intuitionistic fuzzy soft cl...

Influence of Weaving Loom Setting Parameters on Changes of Woven Fabric Structure and Mechanical Properties

Directory of Open Access Journals (Sweden)

Aušra ADOMAITIENĖ

2011-11-01

Full Text Available During the manufacturing of fabric of different raw material there was noticed, that after removing the fabric from weaving loom and after stabilization of fabric structure, the changes of parameters of fabric structure are not regular. During this investigation it was analysed, how weaving loom technological parameters (heald cross moment and initial tension of warp should be chosen and how to predict the changes of fabric structure parameters and its mechanical properties. The dependencies of changes of half-wool fabric structure parameters (weft setting, fabric thickness and projections of fabric cross-section and mechanical properties (breaking force, elongation at break, static friction force and static friction coefficient on weaving loom setting parameters (heald cross moment and initial warp tension were analysed. The orthogonal Box plan of two factors was used, the 3-D dependencies were drawn, and empirical equations of these dependencies were established.http://dx.doi.org/10.5755/j01.ms.17.4.780

Improvement of training set structure in fusion data cleaning using Time-Domain Global Similarity method

International Nuclear Information System (INIS)

Liu, J.; Lan, T.; Qin, H.

2017-01-01

Traditional data cleaning identifies dirty data by classifying original data sequences, which is a class-imbalanced problem since the proportion of incorrect data is much less than the proportion of correct ones for most diagnostic systems in Magnetic Confinement Fusion (MCF) devices. When using machine learning algorithms to classify diagnostic data based on class-imbalanced training set, most classifiers are biased towards the major class and show very poor classification rates on the minor class. By transforming the direct classification problem about original data sequences into a classification problem about the physical similarity between data sequences, the class-balanced effect of Time-Domain Global Similarity (TDGS) method on training set structure is investigated in this paper. Meanwhile, the impact of improved training set structure on data cleaning performance of TDGS method is demonstrated with an application example in EAST POlarimetry-INTerferometry (POINT) system.

New Constraints on Spatial Variations of the Fine Structure Constant from Clusters of Galaxies

Directory of Open Access Journals (Sweden)

Ivan De Martino

2016-12-01

Full Text Available We have constrained the spatial variation of the fine structure constant using multi-frequency measurements of the thermal Sunyaev-Zeldovich effect of 618 X-ray selected clusters. Although our results are not competitive with the ones from quasar absorption lines, we improved by a factor 10 and ∼2.5 previous results from Cosmic Microwave Background power spectrum and from galaxy clusters, respectively.

High variation and very low differentiation in wide ranging plains zebra (Equus quagga): insights from mtDNA and microsatellites.

Science.gov (United States)

Lorenzen, Eline D; Arctander, Peter; Siegismund, Hans R

2008-06-01

Patterns of genetic differentiation in the plains zebra (Equus quagga) were analysed using mitochondrial DNA control region variation and seven microsatellites. The six morphologically defined subspecies of plains zebra lacked the population genetic structure indicative of distinct evolutionary units. Both marker sets showed high levels of genetic variation and very low levels of differentiation. There was no geographical structuring of mitochondrial DNA haplotypes in the phylogenetic tree, and the plains zebra showed the lowest overall differentiation recorded in any African ungulate studied so far. Arid-adapted African ungulates have shown significant regional genetic structuring in support of the Pleistocene refuge theory. This was not the case in the zebra, and the data are discussed in relation to the impact of Pleistocene climate change on a nonbovid member of the savannah ungulate community. The only other species showing a similar absence of genetic structuring is the African buffalo (Syncerus caffer), but this taxon lacks the high levels of morphological variation present in the plains zebra.

Gene transposition causing natural variation for growth in Arabidopsis thaliana.

Science.gov (United States)

Vlad, Daniela; Rappaport, Fabrice; Simon, Matthieu; Loudet, Olivier

2010-05-13

A major challenge in biology is to identify molecular polymorphisms responsible for variation in complex traits of evolutionary and agricultural interest. Using the advantages of Arabidopsis thaliana as a model species, we sought to identify new genes and genetic mechanisms underlying natural variation for shoot growth using quantitative genetic strategies. More quantitative trait loci (QTL) still need be resolved to draw a general picture as to how and where in the pathways adaptation is shaping natural variation and the type of molecular variation involved. Phenotypic variation for shoot growth in the Bur-0 x Col-0 recombinant inbred line set was decomposed into several QTLs. Nearly-isogenic lines generated from the residual heterozygosity segregating among lines revealed an even more complex picture, with major variation controlled by opposite linked loci and masked by the segregation bias due to the defective phenotype of SG3 (Shoot Growth-3), as well as epistasis with SG3i (SG3-interactor). Using principally a fine-mapping strategy, we have identified the underlying gene causing phenotypic variation at SG3: At4g30720 codes for a new chloroplast-located protein essential to ensure a correct electron flow through the photosynthetic chain and, hence, photosynthesis efficiency and normal growth. The SG3/SG3i interaction is the result of a structural polymorphism originating from the duplication of the gene followed by divergent paralogue's loss between parental accessions. Species-wide, our results illustrate the very dynamic rate of duplication/transposition, even over short periods of time, resulting in several divergent--but still functional-combinations of alleles fixed in different backgrounds. In predominantly selfing species like Arabidopsis, this variation remains hidden in wild populations but is potentially revealed when divergent individuals outcross. This work highlights the need for improved tools and algorithms to resolve structural variation

SoftSearch: integration of multiple sequence features to identify breakpoints of structural variations.

Directory of Open Access Journals (Sweden)

Steven N Hart

Full Text Available BACKGROUND: Structural variation (SV represents a significant, yet poorly understood contribution to an individual's genetic makeup. Advanced next-generation sequencing technologies are widely used to discover such variations, but there is no single detection tool that is considered a community standard. In an attempt to fulfil this need, we developed an algorithm, SoftSearch, for discovering structural variant breakpoints in Illumina paired-end next-generation sequencing data. SoftSearch combines multiple strategies for detecting SV including split-read, discordant read-pair, and unmated pairs. Co-localized split-reads and discordant read pairs are used to refine the breakpoints. RESULTS: We developed and validated SoftSearch using real and synthetic datasets. SoftSearch's key features are 1 not requiring secondary (or exhaustive primary alignment, 2 portability into established sequencing workflows, and 3 is applicable to any DNA-sequencing experiment (e.g. whole genome, exome, custom capture, etc.. SoftSearch identifies breakpoints from a small number of soft-clipped bases from split reads and a few discordant read-pairs which on their own would not be sufficient to make an SV call. CONCLUSIONS: We show that SoftSearch can identify more true SVs by combining multiple sequence features. SoftSearch was able to call clinically relevant SVs in the BRCA2 gene not reported by other tools while offering significantly improved overall performance.

Phosphorylation variation during the cell cycle scales with structural propensities of proteins.

Directory of Open Access Journals (Sweden)

Stefka Tyanova

Full Text Available Phosphorylation at specific residues can activate a protein, lead to its localization to particular compartments, be a trigger for protein degradation and fulfill many other biological functions. Protein phosphorylation is increasingly being studied at a large scale and in a quantitative manner that includes a temporal dimension. By contrast, structural properties of identified phosphorylation sites have so far been investigated in a static, non-quantitative way. Here we combine for the first time dynamic properties of the phosphoproteome with protein structural features. At six time points of the cell division cycle we investigate how the variation of the amount of phosphorylation correlates with the protein structure in the vicinity of the modified site. We find two distinct phosphorylation site groups: intrinsically disordered regions tend to contain sites with dynamically varying levels, whereas regions with predominantly regular secondary structures retain more constant phosphorylation levels. The two groups show preferences for different amino acids in their kinase recognition motifs - proline and other disorder-associated residues are enriched in the former group and charged residues in the latter. Furthermore, these preferences scale with the degree of disorderedness, from regular to irregular and to disordered structures. Our results suggest that the structural organization of the region in which a phosphorylation site resides may serve as an additional control mechanism. They also imply that phosphorylation sites are associated with different time scales that serve different functional needs.

49 CFR 229.73 - Wheel sets.

Science.gov (United States)

2010-10-01

... 49 Transportation 4 2010-10-01 2010-10-01 false Wheel sets. 229.73 Section 229.73 Transportation... TRANSPORTATION RAILROAD LOCOMOTIVE SAFETY STANDARDS Safety Requirements Suspension System § 229.73 Wheel sets. (a...) when applied or turned. (b) The maximum variation in the diameter between any two wheel sets in a three...

General inverse problems for regular variation

DEFF Research Database (Denmark)

Damek, Ewa; Mikosch, Thomas Valentin; Rosinski, Jan

2014-01-01

Regular variation of distributional tails is known to be preserved by various linear transformations of some random structures. An inverse problem for regular variation aims at understanding whether the regular variation of a transformed random object is caused by regular variation of components ...

Identification of individual coherent sets associated with flow trajectories using Coherent Structure Coloring

Science.gov (United States)

Schlueter-Kuck, Kristy; Dabiri, John

2017-11-01

In recent years, there has been a proliferation of techniques that aim to characterize fluid flow kinematics on the basis of Lagrangian trajectories of collections of tracer particles. Most of these techniques depend on presence of tracer particles that are initially closely-spaced, in order to compute local gradients of their trajectories. In many applications, the requirement of close tracer spacing cannot be satisfied, especially when the tracers are naturally occurring and their distribution is dictated by the underlying flow. Moreover, current methods often focus on determination of the boundaries of coherent sets, whereas in practice it is often valuable to identify the complete set of trajectories that are coherent with an individual trajectory of interest. We extend the concept of Coherent Structure Coloring to achieve identification of the coherent set associated with individual Lagrangian trajectories. This algorithm is proven successful in identifying coherent structures of varying complexities in canonical unsteady flows. Importantly, although the method is demonstrated here in the context of fluid flow kinematics, the generality of the approach allows for its potential application to other unsupervised clustering problems in dynamical systems. This work was supported by the Department of Defense (DoD) through the National Defense Science & Engineering Graduate Fellowship (NDSEG) Program.

Study of the structure and development of the set of reference materials of composition and structure of heat resisting nickel and intermetallic alloys

Directory of Open Access Journals (Sweden)

E. B. Chabina

2016-01-01

Full Text Available Relevance of research: There are two sizes (several microns and nanodimensional of strengthening j'-phase in single-crystal heat resisting nickel and intermetallic alloys, used for making blades of modern gas turbine engines (GTD. For in-depth study of structural and phase condition of such alloys not only qualitative description of created structure is necessary, but quantitative analysis of alloy components geometrical characteristics. Purpose of the work: Development of reference material sets of heat resisting nickel and intermetallic alloy composition and structure. Research methods: To address the measurement problem of control of structural and geometrical characteristics of single-crystal heat resisting and intermetallic alloys by analytical microscopy and X-ray diffraction analysis the research was carried out using certified measurement techniques on facilities, entered in the Register of Measurement Means of the Russian Federation. The research was carried out on microsections, foils and plates, cut in the plane {100}. Results: It is established that key parameters, defining the properties of these alloys are particle size of strengthening j' -phase, the layer thickness of j-phase between them and parameters of phases lattice. Metrological requirements for reference materials of composition and structure of heat resisting nickel and intermetallic alloys are formulated. The necessary and sufficient reference material set providing the possibility to determine the composition and structure parameters of single-crystal heat resisting nickel and intermetallic alloys is defined. The developed RM sets are certified as in-plant reference materials. Conclusion: The reference materials can be used for graduation of spectral equipment when conducting element analysis of specified class alloys; for calibration of means of measuring alloy structure parameters; for measurement of alloys phases lattice parameters; for structure reference pictures

Discrete variational derivative method a structure-preserving numerical method for partial differential equations

CERN Document Server

Furihata, Daisuke

2010-01-01

Nonlinear Partial Differential Equations (PDEs) have become increasingly important in the description of physical phenomena. Unlike Ordinary Differential Equations, PDEs can be used to effectively model multidimensional systems. The methods put forward in Discrete Variational Derivative Method concentrate on a new class of ""structure-preserving numerical equations"" which improves the qualitative behaviour of the PDE solutions and allows for stable computing. The authors have also taken care to present their methods in an accessible manner, which means that the book will be useful to engineer

Development of a set of process and structure indicators for palliative care: the Europall project

Directory of Open Access Journals (Sweden)

Woitha Kathrin

2012-11-01

Full Text Available Abstract Background By measuring the quality of the organisation of palliative care with process and structure quality indicators (QIs, patients, caregivers and policy makers are able to monitor to what extent recommendations are met, like those of the council of the WHO on palliative care and guidelines. This will support the implementation of public programmes, and will enable comparisons between organisations or countries. Methods As no European set of indicators for the organisation of palliative care existed, such a set of QIs was developed. An update of a previous systematic review was made and extended with more databases and grey literature. In two project meetings with practitioners and experts in palliative care the development process of a QI set was finalised and the QIs were categorized in a framework, covering the recommendations of the Council of Europe. Results The searches resulted in 151 structure and process indicators, which were discussed in steering group meetings. Of those QIs, 110 were eligible for the final framework. Conclusions We developed the first set of QIs for the organisation of palliative care. This article is the first step in a multi step project to identify, validate and pilot QIs.

Variations of magnetic properties of UH3 with modified structure and composition

Directory of Open Access Journals (Sweden)

M. Paukov

2016-06-01

Full Text Available UH3 based hydrides with modified structure and composition can be prepared using high H2 pressures from precursors in the form of rapidly cooled uranium alloys. While the alloys with α-U structure lead to the β-UH3 type of hydrides, γ-U alloys (bcc lead either to α-UH3 hydride type or nanocrystalline β-UH3. The nanocrystalline β-UH3 structure, appearing for Mo alloying, can accommodate in addition numerous other d-metal components, as Ti, Zr, Fe, Nb. The pure Mo alloyed hydrides (UH31−xMox exhibit increasing Curie temperature TC with maximum exceeding 200 K for x = 0.12–0.15. Other components added reduce the TC increment with respect to pure UH3 (170 K. Also alloying by Zr gives a weaker enhancement. Seen globally, the TC variations are rather modest, which reflects the prominence of interaction of U with H. It is suggested that important ingredient is a charge transfer, depopulating the U-6d and 7s states, while the 5f band stays at the Fermi level.

Rib Geometry Explains Variation in Dynamic Structural Response: Potential Implications for Frontal Impact Fracture Risk.

Science.gov (United States)

Murach, Michelle M; Kang, Yun-Seok; Goldman, Samuel D; Schafman, Michelle A; Schlecht, Stephen H; Moorhouse, Kevin; Bolte, John H; Agnew, Amanda M

2017-09-01

The human thorax is commonly injured in motor vehicle crashes, and despite advancements in occupant safety rib fractures are highly prevalent. The objective of this study was to quantify the ability of gross and cross-sectional geometry, separately and in combination, to explain variation of human rib structural properties. One hundred and twenty-two whole mid-level ribs from 76 fresh post-mortem human subjects were tested in a dynamic frontal impact scenario. Structural properties (peak force and stiffness) were successfully predicted (p rib cross-sectional geometry obtained via direct histological imaging (total area, cortical area, and section modulus) and were improved further when utilizing a combination of cross-sectional and gross geometry (robusticity, whole bone strength index). Additionally, preliminary application of a novel, adaptive thresholding technique, allowed for total area and robusticity to be measured on a subsample of standard clinical CT scans with varied success. These results can be used to understand variation in individual rib response to frontal loading as well as identify important geometric parameters, which could ultimately improve injury criteria as well as the biofidelity of anthropomorphic test devices (ATDs) and finite element (FE) models of the human thorax.

The connection-set algebra--a novel formalism for the representation of connectivity structure in neuronal network models.

Science.gov (United States)

Djurfeldt, Mikael

2012-07-01

The connection-set algebra (CSA) is a novel and general formalism for the description of connectivity in neuronal network models, from small-scale to large-scale structure. The algebra provides operators to form more complex sets of connections from simpler ones and also provides parameterization of such sets. CSA is expressive enough to describe a wide range of connection patterns, including multiple types of random and/or geometrically dependent connectivity, and can serve as a concise notation for network structure in scientific writing. CSA implementations allow for scalable and efficient representation of connectivity in parallel neuronal network simulators and could even allow for avoiding explicit representation of connections in computer memory. The expressiveness of CSA makes prototyping of network structure easy. A C+ + version of the algebra has been implemented and used in a large-scale neuronal network simulation (Djurfeldt et al., IBM J Res Dev 52(1/2):31-42, 2008b) and an implementation in Python has been publicly released.

Genome-Wide Mapping of Structural Variations Reveals a Copy Number Variant That Determines Reproductive Morphology in Cucumber

NARCIS (Netherlands)

Zhang, Z.; Mao, L.; Chen, Junshi; Bu, F.; Li, G.; Sun, J.; Li, S.; Sun, H.; Jiao, C.; Blakely, R.; Pan, J.; Cai, R.; Luo, R.; Peer, Van de Y.; Jacobsen, E.; Fei, Z.; Huang, S.

2015-01-01

Structural variations (SVs) represent a major source of genetic diversity. However, the functional impact and formation mechanisms of SVs in plant genomes remain largely unexplored. Here, we report a nucleotide-resolution SV map of cucumber (Cucumis sativas) that comprises 26,788 SVs based on deep

Structural variation in two human genomes mapped at single-nucleotide resolution by whole genome de novo assembly

DEFF Research Database (Denmark)

Li, Yingrui; Zheng, Hancheng; Luo, Ruibang

2011-01-01

Here we use whole-genome de novo assembly of second-generation sequencing reads to map structural variation (SV) in an Asian genome and an African genome. Our approach identifies small- and intermediate-size homozygous variants (1-50 kb) including insertions, deletions, inversions and their precise...

A variational method in out-of-equilibrium physical systems.

Science.gov (United States)

Pinheiro, Mario J

2013-12-09

We propose a new variational principle for out-of-equilibrium dynamic systems that are fundamentally based on the method of Lagrange multipliers applied to the total entropy of an ensemble of particles. However, we use the fundamental equation of thermodynamics on differential forms, considering U and S as 0-forms. We obtain a set of two first order differential equations that reveal the same formal symplectic structure shared by classical mechanics, fluid mechanics and thermodynamics. From this approach, a topological torsion current emerges of the form , where Aj and ωk denote the components of the vector potential (gravitational and/or electromagnetic) and where ω denotes the angular velocity of the accelerated frame. We derive a special form of the Umov-Poynting theorem for rotating gravito-electromagnetic systems. The variational method is then applied to clarify the working mechanism of particular devices.

Fast-slow continuum and reproductive strategies structure plant life-history variation worldwide.

Science.gov (United States)

Salguero-Gómez, Roberto; Jones, Owen R; Jongejans, Eelke; Blomberg, Simon P; Hodgson, David J; Mbeau-Ache, Cyril; Zuidema, Pieter A; de Kroon, Hans; Buckley, Yvonne M

2016-01-05

The identification of patterns in life-history strategies across the tree of life is essential to our prediction of population persistence, extinction, and diversification. Plants exhibit a wide range of patterns of longevity, growth, and reproduction, but the general determinants of this enormous variation in life history are poorly understood. We use demographic data from 418 plant species in the wild, from annual herbs to supercentennial trees, to examine how growth form, habitat, and phylogenetic relationships structure plant life histories and to develop a framework to predict population performance. We show that 55% of the variation in plant life-history strategies is adequately characterized using two independent axes: the fast-slow continuum, including fast-growing, short-lived plant species at one end and slow-growing, long-lived species at the other, and a reproductive strategy axis, with highly reproductive, iteroparous species at one extreme and poorly reproductive, semelparous plants with frequent shrinkage at the other. Our findings remain consistent across major habitats and are minimally affected by plant growth form and phylogenetic ancestry, suggesting that the relative independence of the fast-slow and reproduction strategy axes is general in the plant kingdom. Our findings have similarities with how life-history strategies are structured in mammals, birds, and reptiles. The position of plant species populations in the 2D space produced by both axes predicts their rate of recovery from disturbances and population growth rate. This life-history framework may complement trait-based frameworks on leaf and wood economics; together these frameworks may allow prediction of responses of plants to anthropogenic disturbances and changing environments.

Difference Discrete Variational Principles, Euler-Lagrange Cohomology and Symplectic, Multisymplectic Structures I: Difference Discrete Variational Principle

Institute of Scientific and Technical Information of China (English)

GUO Han-Ying,; LI Yu-Qi; WU Ke1; WANG Shi-Kun

2002-01-01

In this first paper of a series, we study the difference discrete variational principle in the framework of multi-parameter differential approach by regarding the forward difference as an entire geometric object in view of noncommutative differential geometry. Regarding the difference as an entire geometric object, the difference discrete version of Legendre transformation can be introduced. By virtue of this variational principle, we can discretely deal with the variation problems in both the Lagrangian and Hamiltonian formalisms to get difference discrete Euler-Lagrange equations and canonical ones for the difference discrete versions of the classical mechanics and classical field theory.

Structural analysis of a set of proteins resulting from a bacterial genomics project.

Science.gov (United States)

Badger, J; Sauder, J M; Adams, J M; Antonysamy, S; Bain, K; Bergseid, M G; Buchanan, S G; Buchanan, M D; Batiyenko, Y; Christopher, J A; Emtage, S; Eroshkina, A; Feil, I; Furlong, E B; Gajiwala, K S; Gao, X; He, D; Hendle, J; Huber, A; Hoda, K; Kearins, P; Kissinger, C; Laubert, B; Lewis, H A; Lin, J; Loomis, K; Lorimer, D; Louie, G; Maletic, M; Marsh, C D; Miller, I; Molinari, J; Muller-Dieckmann, H J; Newman, J M; Noland, B W; Pagarigan, B; Park, F; Peat, T S; Post, K W; Radojicic, S; Ramos, A; Romero, R; Rutter, M E; Sanderson, W E; Schwinn, K D; Tresser, J; Winhoven, J; Wright, T A; Wu, L; Xu, J; Harris, T J R

2005-09-01

The targets of the Structural GenomiX (SGX) bacterial genomics project were proteins conserved in multiple prokaryotic organisms with no obvious sequence homolog in the Protein Data Bank of known structures. The outcome of this work was 80 structures, covering 60 unique sequences and 49 different genes. Experimental phase determination from proteins incorporating Se-Met was carried out for 45 structures with most of the remainder solved by molecular replacement using members of the experimentally phased set as search models. An automated tool was developed to deposit these structures in the Protein Data Bank, along with the associated X-ray diffraction data (including refined experimental phases) and experimentally confirmed sequences. BLAST comparisons of the SGX structures with structures that had appeared in the Protein Data Bank over the intervening 3.5 years since the SGX target list had been compiled identified homologs for 49 of the 60 unique sequences represented by the SGX structures. This result indicates that, for bacterial structures that are relatively easy to express, purify, and crystallize, the structural coverage of gene space is proceeding rapidly. More distant sequence-structure relationships between the SGX and PDB structures were investigated using PDB-BLAST and Combinatorial Extension (CE). Only one structure, SufD, has a truly unique topology compared to all folds in the PDB. Copyright 2005 Wiley-Liss, Inc.

Common variation in the autism risk gene CNTNAP2, brain structural connectivity and multisensory speech integration.

Science.gov (United States)

Ross, Lars A; Del Bene, Victor A; Molholm, Sophie; Jae Woo, Young; Andrade, Gizely N; Abrahams, Brett S; Foxe, John J

2017-11-01

Three lines of evidence motivated this study. 1) CNTNAP2 variation is associated with autism risk and speech-language development. 2) CNTNAP2 variations are associated with differences in white matter (WM) tracts comprising the speech-language circuitry. 3) Children with autism show impairment in multisensory speech perception. Here, we asked whether an autism risk-associated CNTNAP2 single nucleotide polymorphism in neurotypical adults was associated with multisensory speech perception performance, and whether such a genotype-phenotype association was mediated through white matter tract integrity in speech-language circuitry. Risk genotype at rs7794745 was associated with decreased benefit from visual speech and lower fractional anisotropy (FA) in several WM tracts (right precentral gyrus, left anterior corona radiata, right retrolenticular internal capsule). These structural connectivity differences were found to mediate the effect of genotype on audiovisual speech perception, shedding light on possible pathogenic pathways in autism and biological sources of inter-individual variation in audiovisual speech processing in neurotypicals. Copyright © 2017 Elsevier Inc. All rights reserved.

Greek classicism in living structure? Some deductive pathways in animal morphology.

Science.gov (United States)

Zweers, G A

1985-01-01

Classical temples in ancient Greece show two deterministic illusionistic principles of architecture, which govern their functional design: geometric proportionalism and a set of illusion-strengthening rules in the proportionalism's "stochastic margin". Animal morphology, in its mechanistic-deductive revival, applies just one architectural principle, which is not always satisfactory. Whether a "Greek Classical" situation occurs in the architecture of living structure is to be investigated by extreme testing with deductive methods. Three deductive methods for explanation of living structure in animal morphology are proposed: the parts, the compromise, and the transformation deduction. The methods are based upon the systems concept for an organism, the flow chart for a functionalistic picture, and the network chart for a structuralistic picture, whereas the "optimal design" serves as the architectural principle for living structure. These methods show clearly the high explanatory power of deductive methods in morphology, but they also make one open end most explicit: neutral issues do exist. Full explanation of living structure asks for three entries: functional design within architectural and transformational constraints. The transformational constraint brings necessarily in a stochastic component: an at random variation being a sort of "free management space". This variation must be a variation from the deterministic principle of the optimal design, since any transformation requires space for plasticity in structure and action, and flexibility in role fulfilling. Nevertheless, finally the question comes up whether for animal structure a similar situation exists as in Greek Classical temples. This means that the at random variation, that is found when the optimal design is used to explain structure, comprises apart from a stochastic part also real deviations being yet another deterministic part. This deterministic part could be a set of rules that governs

Variation as a main feature of norm

Directory of Open Access Journals (Sweden)

S. Poladova

2017-09-01

Full Text Available The past half-century has witnessed remarkable growth in the study of language variation, and it has now become a highly productive subfield of research in sociolinguistics. Variability is everywhere in language, from the unique details in each production of a sound or sign to the auditory or visual processing of the linguistic signal. All languages that we can observe today show variation; what is more, they vary in identical ways, namely geographically and socially. It’s no secret that languages like English are full of variation. So, the aim of the article is to detect the reasons of variation and to uncover rates of usage of different free variations for a given set of lexical items. The research work is carried out by using the descriptive, comparative methods by subjecting to analysis the specific language materials. The discovery of law of variation became a starting point for the evolution of linguistics. The problem of search of variation facts and its role in the functioning of language system concerns many specialists from the outset. The scope of the investigation was to set up a system out of chaos of phenomena. Currently, the fact of conditionality of variation by system relations existing in the language is considered to be established.

The structure of carbon black-elastomer composites by small-angle neutron scattering and the method of contrast variation

International Nuclear Information System (INIS)

Hjelm, R.P.; Wampler, W.; Gerspacher, M.

1996-01-01

We have been exploring the use of small-angle neutron scattering and the method of contrast variation to give a new look at a very old problem: reinforcement of elastomers by carbon black in durable rubber products. Carbon black has a hierarchy of structures consisting of particles covalently bound into aggregates, which in turn associate by weak interactions into agglomerates. We found that in one carbon black, HSA, the aggregates are rodlike, containing an average of 4-6 particles. The aggregates have an outer graphitic shell and an inner core of lower density carbon. The core is continuous throughout the carbon black aggregate. Contrast variation of swollen HSA-polyisoprene gels shows that the HSA is completely embedded in polyisoprene and that the agglomerates are formed predominantly by end on associations of the rodlike aggregates. The surface structure of the carbon black appears smooth over length scales above about 10 angstrom. Further studies using production carbon blacks suggest that these structural characteristics are generally present in commercial rubber composites

AN INVESTIGATION OF THE VARIATION OF PORE STRUCTURE IN EUCALYPTUS FIBRE DURING RECYCLING

Directory of Open Access Journals (Sweden)

Wen Jie Guo

2011-04-01

Full Text Available Variation in the pore structure of eucalyptus fibre during recycling was investigated using low-temperature nitrogen adsorption, atomic force microscopy (AFM, and fractal geometry. The Brunauer- Emmett-Teller (BET surface area of the fibre fell to 55.1% of the original value after the first cycle, and to 49.0% after the second cycle, ultimately declining to 35.0% after the fourth. The Barret-Joyner- Halenda (BJH adsorption cumulative pore volume fell to 38.4% of the original by the fourth. After four cycles, the average pore diameter fell to 82% of the original. AFM tests showed that the pore structure in fibre expressed high self-similarity in statistics, and the pore structure in the fibre could be regarded as a fractal. Fractal geometry analysis of the results showed that the fractal dimension of eucalyptus virgin fibre is 2.954. With the number of process cycles increasing, the fractal dimension fell to a minimum of 2.886 after four cycles. The water retention value (WRV of the fibre was proportional to the fractal dimension and the crystallinity of fibre.

Network Ecology and Adolescent Social Structure.

Science.gov (United States)

McFarland, Daniel A; Moody, James; Diehl, David; Smith, Jeffrey A; Thomas, Reuben J

2014-12-01

Adolescent societies-whether arising from weak, short-term classroom friendships or from close, long-term friendships-exhibit various levels of network clustering, segregation, and hierarchy. Some are rank-ordered caste systems and others are flat, cliquish worlds. Explaining the source of such structural variation remains a challenge, however, because global network features are generally treated as the agglomeration of micro-level tie-formation mechanisms, namely balance, homophily, and dominance. How do the same micro-mechanisms generate significant variation in global network structures? To answer this question we propose and test a network ecological theory that specifies the ways features of organizational environments moderate the expression of tie-formation processes, thereby generating variability in global network structures across settings. We develop this argument using longitudinal friendship data on schools (Add Health study) and classrooms (Classroom Engagement study), and by extending exponential random graph models to the study of multiple societies over time.

Efficient iris recognition by characterizing key local variations.

Science.gov (United States)

Ma, Li; Tan, Tieniu; Wang, Yunhong; Zhang, Dexin

2004-06-01

Unlike other biometrics such as fingerprints and face, the distinct aspect of iris comes from randomly distributed features. This leads to its high reliability for personal identification, and at the same time, the difficulty in effectively representing such details in an image. This paper describes an efficient algorithm for iris recognition by characterizing key local variations. The basic idea is that local sharp variation points, denoting the appearing or vanishing of an important image structure, are utilized to represent the characteristics of the iris. The whole procedure of feature extraction includes two steps: 1) a set of one-dimensional intensity signals is constructed to effectively characterize the most important information of the original two-dimensional image; 2) using a particular class of wavelets, a position sequence of local sharp variation points in such signals is recorded as features. We also present a fast matching scheme based on exclusive OR operation to compute the similarity between a pair of position sequences. Experimental results on 2255 iris images show that the performance of the proposed method is encouraging and comparable to the best iris recognition algorithm found in the current literature.

Structure and reactivity of closo- and nido- carboranes

International Nuclear Information System (INIS)

Stanko, V.I.; Brattsev, V.A.; Knyazev, S.P.

1975-01-01

The structure, methods of obtaining and chemical properties of closo- and nido-carboranes are considered in this paper. Some general regularities of chemical reactions involving carborones are revealed. Variations in the physicochemical properties are also considered. Possible mechanisms of reactions with the participation of carboranes are set forth

Variational formulation for dissipative continua and an incremental J-integral

Science.gov (United States)

Rahaman, Md. Masiur; Dhas, Bensingh; Roy, D.; Reddy, J. N.

2018-01-01

Our aim is to rationally formulate a proper variational principle for dissipative (viscoplastic) solids in the presence of inertia forces. As a first step, a consistent linearization of the governing nonlinear partial differential equations (PDEs) is carried out. An additional set of complementary (adjoint) equations is then formed to recover an underlying variational structure for the augmented system of linearized balance laws. This makes it possible to introduce an incremental Lagrangian such that the linearized PDEs, including the complementary equations, become the Euler-Lagrange equations. Continuous groups of symmetries of the linearized PDEs are computed and an analysis is undertaken to identify the variational groups of symmetries of the linearized dissipative system. Application of Noether's theorem leads to the conservation laws (conserved currents) of motion corresponding to the variational symmetries. As a specific outcome, we exploit translational symmetries of the functional in the material space and recover, via Noether's theorem, an incremental J-integral for viscoplastic solids in the presence of inertia forces. Numerical demonstrations are provided through a two-dimensional plane strain numerical simulation of a compact tension specimen of annealed mild steel under dynamic loading.

Uniqueness of the joint measurement and the structure of the set of compatible quantum measurements

Science.gov (United States)

Guerini, Leonardo; Terra Cunha, Marcelo

2018-04-01

We address the problem of characterising the compatible tuples of measurements that admit a unique joint measurement. We derive a uniqueness criterion based on the method of perturbations and apply it to show that extremal points of the set of compatible tuples admit a unique joint measurement, while all tuples that admit a unique joint measurement lie in the boundary of such a set. We also provide counter-examples showing that none of these properties are both necessary and sufficient, thus completely describing the relation between the joint measurement uniqueness and the structure of the compatible set. As a by-product of our investigations, we completely characterise the extremal and boundary points of the set of general tuples of measurements and of the subset of compatible tuples.

Vanadium-rich tourmaline from graphitic rocks at Bítovánky, Czech republic; compositional variation, crystal structure

Czech Academy of Sciences Publication Activity Database

Cempírek, J.; Houzar, S.; Novák, M.; Selway, J.B.; Šrein, Vladimír

2006-01-01

Roč. 28, Spec. pap. (2006), s. 39-41 ISSN 1896-2203. [Central European Mineralogical Conference /1./. Vyšná Boca, 11.09.2006-15.09.2006] Institutional research plan: CEZ:AV0Z30460519 Keywords : V-rich tourmaline * compositional variation * crystal structure Subject RIV: DB - Geology ; Mineralogy

Bioalerts: a python library for the derivation of structural alerts from bioactivity and toxicity data sets.

Science.gov (United States)

Cortes-Ciriano, Isidro

2016-01-01

Assessing compound toxicity at early stages of the drug discovery process is a crucial task to dismiss drug candidates likely to fail in clinical trials. Screening drug candidates against structural alerts, i.e. chemical fragments associated to a toxicological response prior or after being metabolized (bioactivation), has proved a valuable approach for this task. During the last decades, diverse algorithms have been proposed for the automatic derivation of structural alerts from categorical toxicity data sets. Here, the python library bioalerts is presented, which comprises functionalities for the automatic derivation of structural alerts from categorical (dichotomous), e.g. toxic/non-toxic, and continuous bioactivity data sets, e.g. [Formula: see text] or [Formula: see text] values. The library bioalerts relies on the RDKit implementation of the circular Morgan fingerprint algorithm to compute chemical substructures, which are derived by considering radial atom neighbourhoods of increasing bond radius. In addition to the derivation of structural alerts, bioalerts provides functionalities for the calculation of unhashed (keyed) Morgan fingerprints, which can be used in predictive bioactivity modelling with the advantage of allowing for a chemically meaningful deconvolution of the chemical space. Finally, bioalerts provides functionalities for the easy visualization of the derived structural alerts.

Sequencing of a patient with balanced chromosome abnormalities and neurodevelopmental disease identifies disruption of multiple high risk loci by structural variation.

Directory of Open Access Journals (Sweden)

Jonathon Blake

Full Text Available Balanced chromosome abnormalities (BCAs occur at a high frequency in healthy and diseased individuals, but cost-efficient strategies to identify BCAs and evaluate whether they contribute to a phenotype have not yet become widespread. Here we apply genome-wide mate-pair library sequencing to characterize structural variation in a patient with unclear neurodevelopmental disease (NDD and complex de novo BCAs at the karyotype level. Nucleotide-level characterization of the clinically described BCA breakpoints revealed disruption of at least three NDD candidate genes (LINC00299, NUP205, PSMD14 that gave rise to abnormal mRNAs and could be assumed as disease-causing. However, unbiased genome-wide analysis of the sequencing data for cryptic structural variation was key to reveal an additional submicroscopic inversion that truncates the schizophrenia- and bipolar disorder-associated brain transcription factor ZNF804A as an equally likely NDD-driving gene. Deep sequencing of fluorescent-sorted wild-type and derivative chromosomes confirmed the clinically undetected BCA. Moreover, deep sequencing further validated a high accuracy of mate-pair library sequencing to detect structural variants larger than 10 kB, proposing that this approach is powerful for clinical-grade genome-wide structural variant detection. Our study supports previous evidence for a role of ZNF804A in NDD and highlights the need for a more comprehensive assessment of structural variation in karyotypically abnormal individuals and patients with neurocognitive disease to avoid diagnostic deception.

Sequencing of a Patient with Balanced Chromosome Abnormalities and Neurodevelopmental Disease Identifies Disruption of Multiple High Risk Loci by Structural Variation

Science.gov (United States)

Blake, Jonathon; Riddell, Andrew; Theiss, Susanne; Gonzalez, Alexis Perez; Haase, Bettina; Jauch, Anna; Janssen, Johannes W. G.; Ibberson, David; Pavlinic, Dinko; Moog, Ute; Benes, Vladimir; Runz, Heiko

2014-01-01

Balanced chromosome abnormalities (BCAs) occur at a high frequency in healthy and diseased individuals, but cost-efficient strategies to identify BCAs and evaluate whether they contribute to a phenotype have not yet become widespread. Here we apply genome-wide mate-pair library sequencing to characterize structural variation in a patient with unclear neurodevelopmental disease (NDD) and complex de novo BCAs at the karyotype level. Nucleotide-level characterization of the clinically described BCA breakpoints revealed disruption of at least three NDD candidate genes (LINC00299, NUP205, PSMD14) that gave rise to abnormal mRNAs and could be assumed as disease-causing. However, unbiased genome-wide analysis of the sequencing data for cryptic structural variation was key to reveal an additional submicroscopic inversion that truncates the schizophrenia- and bipolar disorder-associated brain transcription factor ZNF804A as an equally likely NDD-driving gene. Deep sequencing of fluorescent-sorted wild-type and derivative chromosomes confirmed the clinically undetected BCA. Moreover, deep sequencing further validated a high accuracy of mate-pair library sequencing to detect structural variants larger than 10 kB, proposing that this approach is powerful for clinical-grade genome-wide structural variant detection. Our study supports previous evidence for a role of ZNF804A in NDD and highlights the need for a more comprehensive assessment of structural variation in karyotypically abnormal individuals and patients with neurocognitive disease to avoid diagnostic deception. PMID:24625750

Hippocampal dentation: Structural variation and its association with episodic memory in healthy adults.

Science.gov (United States)

Fleming Beattie, Julia; Martin, Roy C; Kana, Rajesh K; Deshpande, Hrishikesh; Lee, Seongtaek; Curé, Joel; Ver Hoef, Lawrence

2017-07-01

While the hippocampus has long been identified as a structure integral to memory, the relationship between morphology and function has yet to be fully explained. We present an analysis of hippocampal dentation, a morphological feature previously unexplored in regard to its relationship with episodic memory. "Hippocampal dentation" in this case refers to surface convolutions, primarily present in the CA1/subiculum on the inferior aspect of the hippocampus. Hippocampal dentation was visualized using ultra-high resolution structural MRI and evaluated using a novel visual rating scale. The degree of hippocampal dentation was found to vary considerably across individuals, and was positively associated with verbal memory recall and visual memory recognition in a sample of 22 healthy adults. This study is the first to characterize the variation in hippocampal dentation in a healthy cohort and to demonstrate its association with aspects of episodic memory. Copyright © 2017 Elsevier Ltd. All rights reserved.

New constraints on variations of the fine structure constant from CMB anisotropies

International Nuclear Information System (INIS)

Menegoni, Eloisa; Melchiorri, Alessandro; Galli, Silvia; Bartlett, James G.; Martins, C. J. A. P.

2009-01-01

We demonstrate that recent measurements of cosmic microwave background temperature and polarization anisotropy made by the ACBAR, QUAD, and BICEP experiments substantially improve the cosmological constraints on possible variations of the fine structure constant in the early universe. This data, combined with the five year observations from the WMAP mission, yield the constraint α/α 0 =0.987±0.012 at 68% C.L. The inclusion of the new Hubble Space Telescope constraints on the Hubble constant further increases the accuracy to α/α 0 =1.001±0.007 at 68% C.L., bringing possible deviations from the current value below the 1% level and improving previous constraints by a factor of ∼3.

Degenerate variational integrators for magnetic field line flow and guiding center trajectories

Science.gov (United States)

Ellison, C. L.; Finn, J. M.; Burby, J. W.; Kraus, M.; Qin, H.; Tang, W. M.

2018-05-01

Symplectic integrators offer many benefits for numerically approximating solutions to Hamiltonian differential equations, including bounded energy error and the preservation of invariant sets. Two important Hamiltonian systems encountered in plasma physics—the flow of magnetic field lines and the guiding center motion of magnetized charged particles—resist symplectic integration by conventional means because the dynamics are most naturally formulated in non-canonical coordinates. New algorithms were recently developed using the variational integration formalism; however, those integrators were found to admit parasitic mode instabilities due to their multistep character. This work eliminates the multistep character, and therefore the parasitic mode instabilities via an adaptation of the variational integration formalism that we deem "degenerate variational integration." Both the magnetic field line and guiding center Lagrangians are degenerate in the sense that the resultant Euler-Lagrange equations are systems of first-order ordinary differential equations. We show that retaining the same degree of degeneracy when constructing discrete Lagrangians yields one-step variational integrators preserving a non-canonical symplectic structure. Numerical examples demonstrate the benefits of the new algorithms, including superior stability relative to the existing variational integrators for these systems and superior qualitative behavior relative to non-conservative algorithms.

Line-edge roughness induced single event transient variation in SOI FinFETs

International Nuclear Information System (INIS)

Wu Weikang; An Xia; Jiang Xiaobo; Chen Yehua; Liu Jingjing; Zhang Xing; Huang Ru

2015-01-01

The impact of process induced variation on the response of SOI FinFET to heavy ion irradiation is studied through 3-D TCAD simulation for the first time. When FinFET biased at OFF state configuration (V gs = 0, V ds = V dd ) is struck by a heavy ion, the drain collects ionizing charges under the electric field and a current pulse (single event transient, SET) is consequently formed. The results reveal that with the presence of line-edge roughness (LER), which is one of the major variation sources in nano-scale FinFETs, the device-to-device variation in terms of SET is observed. In this study, three types of LER are considered: type A has symmetric fin edges, type B has irrelevant fin edges and type C has parallel fin edges. The results show that type A devices have the largest SET variation while type C devices have the smallest variation. Further, the impact of the two main LER parameters, correlation length and root mean square amplitude, on SET variation is discussed as well. The results indicate that variation may be a concern in radiation effects with the down scaling of feature size. (paper)

Genetic variation, population structure and linkage disequilibrium in Switchgrass with ISSR, SCoT and EST-SSR markers.

Science.gov (United States)

Zhang, Yu; Yan, Haidong; Jiang, Xiaomei; Wang, Xiaoli; Huang, Linkai; Xu, Bin; Zhang, Xinquan; Zhang, Lexin

2016-01-01

To evaluate genetic variation, population structure, and the extent of linkage disequilibrium (LD), 134 switchgrass ( Panicum virgatum L.) samples were analyzed with 51 markers, including 16 ISSRs, 20 SCoTs, and 15 EST-SSRs. In this study, a high level of genetic variation was observed in the switchgrass samples and they had an average Nei's gene diversity index (H) of 0.311. A total of 793 bands were obtained, of which 708 (89.28 %) were polymorphic. Using a parameter marker index (MI), the efficiency of the three types of markers (ISSR, SCoT, and EST-SSR) in the study were compared and we found that SCoT had a higher marker efficiency than the other two markers. The 134 switchgrass samples could be divided into two sub-populations based on STRUCTURE, UPGMA clustering, and principal coordinate analyses (PCA), and upland and lowland ecotypes could be separated by UPGMA clustering and PCA analyses. Linkage disequilibrium analysis revealed an average r 2 of 0.035 across all 51 markers, indicating a trend of higher LD in sub-population 2 than that in sub-population 1 ( P  < 0.01). The population structure revealed in this study will guide the design of future association studies using these switchgrass samples.

Cytoplasmic genetic variation and extensive cytonuclear interactions influence natural variation in the metabolome

DEFF Research Database (Denmark)

Joseph, Bindu; Corwin, Jason A.; Li, Baohua

2013-01-01

Understanding genome to phenotype linkages has been greatly enabled by genomic sequencing. However, most genome analysis is typically confined to the nuclear genome. We conducted a metabolomic QTL analysis on a reciprocal RIL population structured to examine how variation in the organelle genomes...... was a central hub in the epistatic network controlling the plant metabolome. This epistatic influence manifested such that the cytoplasmic background could alter or hide pairwise epistasis between nuclear loci. Thus, cytoplasmic genetic variation plays a central role in controlling natural variation...... in metabolomic networks. This suggests that cytoplasmic genomes must be included in any future analysis of natural variation....

Alternate superior Julia sets

International Nuclear Information System (INIS)

Yadav, Anju; Rani, Mamta

2015-01-01

Alternate Julia sets have been studied in Picard iterative procedures. The purpose of this paper is to study the quadratic and cubic maps using superior iterates to obtain Julia sets with different alternate structures. Analytically, graphically and computationally it has been shown that alternate superior Julia sets can be connected, disconnected and totally disconnected, and also fattier than the corresponding alternate Julia sets. A few examples have been studied by applying different type of alternate structures

Assessment of semiempirical enthalpy of formation in solution as an effective energy function to discriminate native-like structures in protein decoy sets.

Science.gov (United States)

Urquiza-Carvalho, Gabriel Aires; Fragoso, Wallace Duarte; Rocha, Gerd Bruno

2016-08-05

In this work, we tested the PM6, PM6-DH+, PM6-D3, and PM7 enthalpies of formation in aqueous solution as scoring functions across 33 decoy sets to discriminate native structures or good models in a decoy set. In each set these semiempirical quantum chemistry methods were compared according to enthalpic and geometric criteria. Enthalpically, we compared the methods according to how much lower was the enthalpy of each native, when compared with the mean enthalpy of its set. Geometrically, we compared the methods according to the fraction of native contacts (Q), which is a measure of geometric closeness between an arbitrary structure and the native. For each set and method, the Q of the best decoy was compared with the Q0 , which is the Q of the decoy closest to the native in the set. It was shown that the PM7 method is able to assign larger energy differences between the native structure and the decoys in a set, arguably because of a better description of dispersion interactions, however PM6-DH+ was slightly better than the rest at selecting geometrically good models in the absence of a native structure in the set. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Enhanced sensitivity to the time variation of the fine-structure constant and mp/me in diatomic molecules: A closer examination of silicon monobromide

International Nuclear Information System (INIS)

Beloy, K.; Borschevsky, A.; Schwerdtfeger, P.; Flambaum, V. V.

2010-01-01

Recently it was pointed out that transition frequencies in certain diatomic molecules have an enhanced sensitivity to variations in the fine-structure constant α and the proton-to-electron mass ratio m p /m e due to a near cancellation between the fine structure and vibrational interval in a ground electronic multiplet [V. V. Flambaum and M. G. Kozlov, Phys. Rev. Lett. 99, 150801 (2007)]. One such molecule possessing this favorable quality is silicon monobromide. Here we take a closer examination of SiBr as a candidate for detecting variations in α and m p /m e . We analyze the rovibronic spectrum by employing the most accurate experimental data available in the literature and perform ab initio calculations to determine the precise dependence of the spectrum on variations in α. Furthermore, we calculate the natural linewidths of the rovibronic levels, which place a fundamental limit on the accuracy to which variations may be determined.

Cross-Scale Variation in Biodiversity-Environment Links Illustrated by Coastal Sandflat Communities.

Directory of Open Access Journals (Sweden)

Casper Kraan

Full Text Available Spatial variation in the composition of communities is the product of many biotic and environmental interactions. A neglected factor in the analysis of community distribution patterns is the multi-scale nature of the data, which has implications for understanding ecological processes and the development of conservation and environmental management practice. Drawing on recently established multivariate spatial analyses, we investigate whether including relationships between spatial structure and abiotic variables enable us to better discern patterns of species and communities across scales. Data comprised 1200 macrozoobenthic samples collected over an array of distances (30 cm to 1 km in three New Zealand harbours, as well as commonly used abiotic variables, such as sediment characteristics and chlorophyll a concentrations, measured at the same scales. Moran's eigenvector mapping was used to extract spatial scales at which communities were structured. Benthic communities, representing primarily bivalves, polychaetes and crustaceans, were spatially structured at four spatial scales, i.e. >100 m, 50-100 m, 50-15 m, and < 15 m. A broad selection of abiotic variables contributed to the large-scale variation, whereas a more limited set explained part of the fine-scale community structure. Across all scales, less than 30% of the variation in spatial structure was captured by our analysis. The large number of species (48 making up the 10 highest species scores based on redundancy analyses illustrate the variability of species-scale associations. Our results emphasise that abiotic variables and biodiversity are related at all scales investigated and stress the importance of assessing the relationship between environmental variables and the abundance and distribution of biological assemblages across a range of different scales.

Structure variations of pumpkin balloon

Science.gov (United States)

Yajima, N.; Izutsu, N.; Honda, H.

2004-01-01

A lobed pumpkin balloon by 3-D gore design concept is recognized as a basic form for a super-pressure balloon. This paper deals with extensions of this design concept for other large pressurized membrane structures, such as a stratospheric airship and a balloon of which volume is controllable. The structural modifications are performed by means of additional ropes, belts or a strut. When the original pumpkin shape is modified by these systems, the superior characteristics of the 3-D gore design, incorporating large bulges with a small local radius and unidirectional film tension, should be maintained. Improved design methods which are adequate for the above subjects will be discussed in detail. Application for ground structures are also mentioned.

High variation and very low differentiation in wide ranging plains zebra (Equus quagga): insights from mtDNA and microsatellites

DEFF Research Database (Denmark)

Lorenzen, Eline D; Arctander, Peter; Siegismund, Hans R

2008-01-01

units. Both marker sets showed high levels of genetic variation and very low levels of differentiation. There was no geographical structuring of mitochondrial DNA haplotypes in the phylogenetic tree, and the plains zebra showed the lowest overall differentiation recorded in any African ungulate studied...

Rate-, temperature-, and structure-dependent yield kinetics of isotactic polypropylene

NARCIS (Netherlands)

Erp, van T.B.; Cavallo, D.; Peters, G.W.M.; Govaert, L.E.

2012-01-01

The influence of cooling rate on the structure and resulting mechanical performance is explored for a set of isotactic polypropylenes with varying molecular weight, insertion of counits, and addition of a nucleating agent. A continuous variation of crystal type (a–mesomorphic phase competition) and

Spatio-temporal patterns in the coral reef communities of the Spermonde Archipelago, 2012–2014, II: Fish assemblages display structured variation related to benthic condition

DEFF Research Database (Denmark)

Plass-Johnson, Jeremiah Grahm; Teichberg, Mirta; Bednarz, Vanessa N.

2018-01-01

The Spermonde Archipelago is a complex of ~70 mostly populated islands off Southwest Sulawesi, Indonesia, in the center of the Coral Triangle. The reefs in this area are exposed to a high level of anthropogenic disturbances. Previous studies have shown that variation in the benthos is strongly...... with distance, while few species were present across the entire range of sites. Relating fish communities to benthic composition using a multivariate generalized linear model confirmed that fish groups relate to structural complexity (rugosity) or differing benthic groups; either algae, reef builders (coral...... and crustose coralline algae) or invertebrates and rubble. From these relationships we can identify sets of fish species that may be lost given continued degradation of the Spermonde reefs. Lastly, the incorporation of water quality, benthic and fish indices indicates that local coral reefs responded...

Damage detection and quantification using mode curvature variation on framed structures: analysis of the preliminary results

Science.gov (United States)

Iacovino, Chiara; Ditommaso, Rocco; Auletta, Gianluca; Ponzo, Felice C.

2017-04-01

Continuous monitoring based on vibrational identification methods is increasingly employed for the evaluation of the state of health of existing buildings after strong motion earthquake. Different damage identification methods are based on the variations of damage indices defined in terms modal (eigenfrequencies, mode shapes, and modal damping) and/or non-modal parameters. Most of simplified methods for structural health monitoring and damage detection are based on the evaluation of the dynamic characteristics evolution associated to the fundamental mode of vibration of a monitored structure. Aim of this work is the upgrade of an existing method for damage localization on framed structures during a moderate/destructive earthquake. The existing version of the method is based on the comparison of the geometric characteristics (with particular reference to the mode curvature) exhibited by the structures, related to fundamental mode of vibration, before and during an earthquake. The approach is based on the use of a nonlinear filter, the band-variable filter, based on the Stockwell Transform able to extract the nonlinear response of each mode of vibration. The new version of the method provides the possibility to quantify a possible damage occurred on the monitored structure linking the mode curvature variation with the maximum inter-story drift. This paper shows the preliminary results obtained from several simulations on nonlinear numerical models of reinforced concrete framed structures, designed for only gravity loads, without and with the presence of infill panels. Furthermore, a correlation between maximum mode curvature difference and maximum inter-story drift has been defined for the different numerical models in order to quantify the structural damage. Acknowledgements This study was partially funded by the Italian Department of Civil Protection within the project DPC-RELUIS 2016 - RS4 ''Seismic observatory of structures and health monitoring'' and by the

On polar daily geomagnetic variation

Directory of Open Access Journals (Sweden)

Paola De Michelis

2015-11-01

Full Text Available The aim of this work is to investigate the nature of the daily magnetic field perturbations produced by ionospheric and magnetospheric currents at high latitudes. We analyse the hourly means of the X and Y geomagnetic field components recorded by a meridian chain of permanent geomagnetic observatories in the polar region of the Northern Hemisphere during a period of four years (1995-1998 around the solar minimum. We apply a mathematical method, known as natural orthogonal component (NOC, which is capable of characterizing the dominant modes of the geomagnetic field daily variability through a set of empirical orthogonal functions (EOFs. Using the first two modes we reconstruct a two-dimensional equivalent current representation of the ionospheric electric currents, which contribute substantially to the geomagnetic daily variations. The obtained current structures resemble the equivalent current patterns of DP2 and DP1. We characterize these currents by studying their evolution with the geomagnetic activity level and by analysing their dependence on the interplanetary magnetic field. The obtained results support the idea of a coexistence of two main processes during all analysed period although one of them, the directly driven process, represents the dominant component of the geomagnetic daily variation.

A systematic review of structured versus non-structured breastfeeding programmes to support the initiation and duration of exclusive breastfeeding in acute and primary healthcare settings.

Science.gov (United States)

Beake, Sarah; Pellowe, Carol; Dykes, Fiona; Schmied, Virginia; Bick, Debra

2011-01-01

Background: Breastfeeding has many important health benefits for the woman and her baby. Despite evidence of benefit from a large number of well conducted studies, breastfeeding uptake and the duration of exclusive breastfeeding remain low in many countries. In order to improve breastfeeding rates, policy and guidelines at global, individual country level and in local healthcare settings have recommended that structured programmes to support breastfeeding should be introduced. The objective of this review was to consider the evidence of outcomes of structured compared with non-structured breastfeeding programmes in acute maternity care settings to support initiation and duration of exclusive breastfeeding. The definition of structured programme used included a multi-faceted or single intervention approach to support breastfeeding; definition of non-structured included support offered within standard care. The review considered quantitative and qualitative studies which addressed outcomes following the introduction of a structured programme in acute healthcare settings to support breastfeeding compared with no programme. The primary outcomes of interest were uptake of breastfeeding and duration of exclusive breastfeeding (only breast milk, including milk expressed). Studies which only considered community based interventions were not included. A search of the literature published between 1992 and 2010 was conducted, which followed a four step process. After a limited search of MEDLINE and CINAHL to identify key words contained in the title or abstract and index terms to describe relevant interventions, a second extensive search was undertaken using identified key words and index terms. The third step included a search of reference lists and bibliographies of relevant articles and the fourth step included a search of grey and unpublished literature and national databasesMethodological quality: Methodological quality was assessed using checklists developed by the

Variations of Hodge Structure Considered as an Exterior Differential System: Old and New Results

Directory of Open Access Journals (Sweden)

James Carlson

2009-09-01

Full Text Available This paper is a survey of the subject of variations of Hodge structure (VHS considered as exterior differential systems (EDS. We review developments over the last twenty-six years, with an emphasis on some key examples. In the penultimate section we present some new results on the characteristic cohomology of a homogeneous Pfaffian system. In the last section we discuss how the integrability conditions of an EDS affect the expected dimension of an integral submanifold. The paper ends with some speculation on EDS and Hodge conjecture for Calabi-Yau manifolds.

Basic Structure of Some Classes of Neutrosophic Crisp Nearly Open Sets & Possible Application to GIS Topology

Directory of Open Access Journals (Sweden)

A. A. Salama

2015-01-01

Full Text Available Since the world is full of indeterminacy, the neutrosophics found their place into contemporary research. The fundamental concepts of neutrosophic set, introduced by Smarandache and Salama et al. In Geographical information systems (GIS there is a need to model spatial regions with indeterminate boundary and under indeterminacy. In this paper the structure of some classes of neutrosophic crisp nearly open sets are investigated and some applications are given. Finally we generalize the crisp topological and intuitioistic studies to the notion of neutrosophic crisp set. Possible applications to GIS topological rules are touched upon.

Solid mechanics a variational approach

CERN Document Server

Dym, Clive L

2013-01-01

Solid Mechanics: A Variational Approach, Augmented Edition presents a lucid and thoroughly developed approach to solid mechanics for students engaged in the study of elastic structures not seen in other texts currently on the market. This work offers a clear and carefully prepared exposition of variational techniques as they are applied to solid mechanics. Unlike other books in this field, Dym and Shames treat all the necessary theory needed for the study of solid mechanics and include extensive applications. Of particular note is the variational approach used in developing consistent structural theories and in obtaining exact and approximate solutions for many problems.  Based on both semester and year-long courses taught to undergraduate seniors and graduate students, this text is geared for programs in aeronautical, civil, and mechanical engineering, and in engineering science. The authors’ objective is two-fold: first, to introduce the student to the theory of structures (one- and two-dimensional) as ...

Evaluation of Different Methods for Identification of Structural Alerts Using Chemical Ames Mutagenicity Data Set as a Benchmark.

Science.gov (United States)

Yang, Hongbin; Li, Jie; Wu, Zengrui; Li, Weihua; Liu, Guixia; Tang, Yun

2017-06-19

Identification of structural alerts for toxicity is useful in drug discovery and other fields such as environmental protection. With structural alerts, researchers can quickly identify potential toxic compounds and learn how to modify them. Hence, it is important to determine structural alerts from a large number of compounds quickly and accurately. There are already many methods reported for identification of structural alerts. However, how to evaluate those methods is a problem. In this paper, we tried to evaluate four of the methods for monosubstructure identification with three indices including accuracy rate, coverage rate, and information gain to compare their advantages and disadvantages. The Kazius' Ames mutagenicity data set was used as the benchmark, and the four methods were MoSS (graph-based), SARpy (fragment-based), and two fingerprint-based methods including Bioalerts and the fingerprint (FP) method we previously used. The results showed that Bioalerts and FP could detect key substructures with high accuracy and coverage rates because they allowed unclosed rings and wildcard atom or bond types. However, they also resulted in redundancy so that their predictive performance was not as good as that of SARpy. SARpy was competitive in predictive performance in both training set and external validation set. These results might be helpful for users to select appropriate methods and further development of methods for identification of structural alerts.

Time-Dependent Variations in Structure of Sheep Wool Irradiated by Electron Beam

Directory of Open Access Journals (Sweden)

Zuzana Hanzlíková

2017-01-01

Full Text Available Wool scoured in tap water with no special degreasing and containing a balanced humidity responding to usual laboratory conditions was irradiated by accelerated electron beam in the range of 0–350 kGy dose. Time variations of the wool structure were measured using FTIR, Raman, and EPR spectroscopy. The aim was to determine whether preexposure treatment of the wool, as well as postexposure time, affects the properties of the irradiated wool. Reactive products such as S-sulfonate, cystine monoxide, cystine dioxide, cysteic acid, disulphides, and carboxylates displayed a considerable fluctuation in quantity depending on both the absorbed dose and time. Mutual transformations of S-oxidized products into cysteic acid appeared to be faster than those in dry and degreased wool assuming that the present humidity inside the fibres is decisive as an oxygen source. EPR results indicated a longer lifetime for free radicals induced by lower doses compared with the radicals generated by higher ones. The pattern of the conformational composition of the secondary structure (α-helix, β-sheet, random, and residual conformations also showed a large variability depending on absorbed dose as well as postexposure time. The most stable secondary structure was observed in nonirradiated wool but even this showed a small but observable change after a longer time, too.

Solar UV Variations During the Decline of Cycle 23

Science.gov (United States)

DeLand, Matthew, T.; Cebula, Richard P.

2011-01-01

Characterization of temporal and spectral variations in solar ultraviolet irradiance over a solar cycle is essential for understanding the forcing of Earth's atmosphere and climate. Satellite measurements of solar UV variability for solar cycles 21, 22, and 23 show consistent solar cycle irradiance changes at key wavelengths (e.g. 205 nm, 250 nm) within instrumental uncertainties. All historical data sets also show the same relative spectral dependence for both short-term (rotational) and long-term (solar cycle) variations. Empirical solar irradiance models also produce long-term solar UV variations that agree well with observational data. Recent UV irradiance data from the Solar Radiation and Climate Experiment (SORCE) Spectral Irradiance Monitor (SIM) and Solar Stellar Irradiance Comparison Experiment (SOLSTICE) instruments covering the declining phase of Cycle 23 present a different picture oflong-term solar variations from previous results. Time series of SIM and SOLSTICE spectral irradiance data between 2003 and 2007 show solar variations that greatly exceed both previous measurements and predicted irradiance changes over this period, and the spectral dependence of the SIM and SOLSTICE variations during these years do not show features expected from solar physics theory. The use of SORCE irradiance variations in atmospheric models yields substantially different middle atmosphere ozone responses in both magnitude and vertical structure. However, short-term solar variability derived from SIM and SOLSTICE UV irradiance data is consistent with concurrent solar UV measurements from other instruments, as well as previous results, suggesting no change in solar physics. Our analysis of short-term solar variability is much less sensitive to residual instrument response changes than the observations of long-term variations. The SORCE long-term UV results can be explained by under-correction of instrument response changes during the first few years of measurements

Accuracy in tangential breast treatment set-up

International Nuclear Information System (INIS)

Tienhoven, G. van; Lanson, J.H.; Crabeels, D.; Heukelom, S.; Mijnheer, B.J.

1991-01-01

To test accuracy and reproducibility of tangential breast treatment set-up used in The Netherlands Cancer Institute, a portal imaging study was performed in 12 patients treated for early stage breast cancer. With an on-line electronic portal imaging device (EPID) images were obtained of each patient in several fractions and compared with simulator films and with each other. In 5 patients multiple images (on the average 7) per fraction were obtained to evaluate set-up variations due to respiratory movement. The central lung distance (CLD) and other set-up parameters varied within 1 fraction about 1mm (1SD). The average variation of these parameters between various fractions was about 2 mm (1SD). The differences between simulator and treatment set-up over all patients and all fractions was on the average 2-3mm for the central beam edge to skin distance and CLD. It can be concluded that the tangential breast treatment set-up is very stable and reproducible and that respiration does not have a significant influence on treatment volume. EPID appears to be an adequate tool for studies of treatment set-up accuracy like this. (author). 35 refs.; 2 figs.; 3 tabs

Structural analysis by load combination for conceptual design of HCCR TBM-set

Energy Technology Data Exchange (ETDEWEB)

Lee, Dong Won, E-mail: dwlee@kaeri.re.kr [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Jin, Hyung Gon; Lee, Eo Hwak; Kim, Suk-Kwon; Yoon, Jae Sung; Park, Seong Dae [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Shin, Kyu In [Gentec Co., Daejeon (Korea, Republic of); Cho, Seungyon [National Fusion Research Institute, Daejeon (Korea, Republic of)

2016-11-01

Highlights: • The structural analyses of the load combination are performed for the HCCR TBM-set. • Structural analyses are performed with the conventional CFD and FEM codes (ANSYS-CFX and ANSYS). • The results of stresses and deformations for all the loads conditions are confirmed to meet the design criteria. - Abstract: Using a conceptual design of the Korean Helium Cooled Ceramic Reflector (HCCR) Test Blanket Module (TBM) including the TBM-shield for testing in ITER, a structural analysis is performed according to the selected Load Combinations (LCs), which is described in the TBM Port Plug (TBM PP) System Load Specifications. Single load analyses are performed such as dead weight (DW), operating pressure (PresO), operating temperature (THO), electromagnetic (EM; MD-I, MD-II, and MD-IV), seismic (SL-1, SL-2, and SMHV), and in-TBM LOCA-IV. In addition, their results are superposed for the selected LCs. Through an analysis with 14 single load cases and 10 LC cases, it is confirmed that all load combination results meet the design criteria from the stress breakdown analysis according to the RCC-MRx.

Toward a new conception of conceptions: Interplay of talk, gestures, and structures in the setting

Science.gov (United States)

Givry, Damien; Roth, Wolff-Michael

2006-12-01

Most studies about students' conceptions and conceptual change are based exclusively on the analysis language, which is treated as a tool to make private contents of the mind public to researchers. Following recent studies that focused on (a) language and discursive practice and (b) the pragmatics of communication that draws on talk, gestures, and semiotic resources in the setting, we propose a redefinition of the nature of conception. Conceptions are understood as the dialectical relation of simultaneously available speech, gestures, and contextual structures that cannot be reduced to verbal rendering because gestures and contextual structures constitute different modalities in the communication. Drawing on data collected during a physics unit about gas taught in French tenth grade classrooms, we show why an appropriate account of conceptions requires: (a) gestures simultaneously produced with talk; and (b) identification of the relevant structures in the setting used by the participants as meaning-making (semiotic) resources. We propose to: (a) reconceptualize the notion of conception as consisting of a dialectical unit of all relevant semiotic (meaning-making) resources publicly made available by a speaker (talk, gesture, context); and (b) consider conceptual change through the temporal evolution of the dialectical unit defined in this manner.

A modular structure to accident identification using neural networks

International Nuclear Information System (INIS)

Duque Estrada, Cassius Rodrigo

2005-01-01

This work uses the accident identification method based on Artificial Neural Networks (ANN) as basic blocks of a modular structure, allowing the inclusion of new accidents to be identified without modifying the ANN already trained. This structure comprises several modules for accident identification and one module for analysis. Each identification module follows the structure of the basic block. The identification modules are responsible for the recognition of an accident belonging to the specific set of events for which it were trained. The analysis module processes the output from the identification module to determine the system response. In order to test this structure it was proposed a transient identification problem comprising fifty accidents distributed in five identification modules. The results have demonstrated that the accident identification method used as basic block of a modular structure allows the inclusion of new sets of accidents, or variations of a same accident, without modifying the ANN already trained. For this, it is enough to include into the system an specific module for this new set of accidents. (author)

Strategy for reduced calibration sets to develop quantitative structure-retention relationships in high-performance liquid chromatography

Energy Technology Data Exchange (ETDEWEB)

Andries, Jan P.M. [University of Professional Education, Department of Life Sciences, P.O. Box 90116, 4800 RA Breda (Netherlands); Claessens, Henk A. [University of Professional Education, Department of Life Sciences, P.O. Box 90116, 4800 RA Breda (Netherlands); Eindhoven University of Technology, Department of Chemical Engineering and Chemistry, Laboratory of Polymer Chemistry, P.O. Box 513 (Helix, STW 1.35), 5600 MB Eindhoven (Netherlands); Heyden, Yvan Vander [Department of Analytical Chemistry and Pharmaceutical Technology, Vrije Universiteit Brussel-VUB, Laarbeeklaan 103, B-1090 Brussels (Belgium); Buydens, Lutgarde M.C., E-mail: L.Buydens@science.ru.nl [Institute for Molecules and Materials, Radboud University Nijmegen, Toernooiveld 1, 6525 ED Nijmegen (Netherlands)

2009-10-12

In high-performance liquid chromatography, quantitative structure-retention relationships (QSRRs) are applied to model the relation between chromatographic retention and quantities derived from molecular structure of analytes. Classically a substantial number of test analytes is used to build QSRR models. This makes their application laborious and time consuming. In this work a strategy is presented to build QSRR models based on selected reduced calibration sets. The analytes in the reduced calibration sets are selected from larger sets of analytes by applying the algorithm of Kennard and Stone on the molecular descriptors used in the QSRR concerned. The strategy was applied on three QSRR models of different complexity, relating logk{sub w} or log k with either: (i) log P, the n-octanol-water partition coefficient, (ii) calculated quantum chemical indices (QCI), or (iii) descriptors from the linear solvation energy relationship (LSER). Models were developed and validated for 76 reversed-phase high-performance liquid chromatography systems. From the results we can conclude that it is possible to develop log P models suitable for the future prediction of retentions with as few as seven analytes. For the QCI and LSER models we derived the rule that three selected analytes per descriptor are sufficient. Both the dependent variable space, formed by the retention values, and the independent variable space, formed by the descriptors, are covered well by the reduced calibration sets. Finally guidelines to construct small calibration sets are formulated.

Tuning up mind's pattern to nature's own idea: Eddington's early twenties case for variational derivatives

Science.gov (United States)

Smadja, Ivahn

This paper sets out to show how Eddington's early twenties case for variational derivatives significantly bears witness to a steady and consistent shift in focus from a resolute striving for objectivity towards "selective subjectivism" and structuralism. While framing his so-called "Hamiltonian derivatives" along the lines of previously available variational methods allowing to derive gravitational field equations from an action principle, Eddington assigned them a theoretical function of his own devising in The Mathematical Theory of Relativity (1923). I make clear that two stages should be marked out in Eddington's train of thought if the meaning of such variational derivatives is to be adequately assessed. As far as they were originally intended to embody the mind's collusion with nature by linking atomicity of matter with atomicity of action, variational derivatives were at first assigned a dual role requiring of them not only to express mind's craving for permanence but also to tune up mind's privileged pattern to "Nature's own idea". Whereas at a later stage, as affine field theory would provide a framework for world-building, such "Hamiltonian differentiation" would grow out of tune through gauge-invariance and, by disregarding how mathematical theory might precisely come into contact with actual world, would be turned into a mere heuristic device for structural knowledge.

Structure and amount of genetic variation at minisatellite loci within the subspecies complex of Phoca vitulina (the harbour seal)

NARCIS (Netherlands)

Kappe, A.L.; Bijlsma, R.; Osterhaus, ADME; van Delden, W.; van de Zande, L.

The structure and amount of genetic variation within and between three subspecies of the harbour seal Phoca vitulina was assessed by multilocus DNA fingerprinting. Bandsharing similarity indicates that the subspecies Phoca vitulina richarhsi (Alaska, East Pacific) is clearly separated from the other

Cosmological constants and variations

International Nuclear Information System (INIS)

Barrow, John D

2005-01-01

We review properties of theories for the variation of the gravitation and fine structure 'constants'. We highlight some general features of the cosmological models that exist in these theories with reference to recent quasar data that is consistent with time-variation in the fine structure 'constant' since a redshift of 3.5. The behaviour of a simple class of varying alpha cosmologies is outlined in the light of all the observational constraints. We also discuss some of the consequences of varying 'constants' for oscillating universes and show by means of exact solutions that they appear to evolve monotonically in time even though the scale factor of the universe oscillates

Phonon structure in proximity tunnel junctions

International Nuclear Information System (INIS)

Zarate, H.G.; Carbotte, J.P.

1985-01-01

We have iterated to convergence, for the first time, a set of four coupled real axis Eliashberg equations for the superconducting gap and renormalization functions on each side of a proximity sandwich. We find that the phenomenological procedures developed to extract the size of the normal side electron-phonon interaction from tunneling data are often reasonable but may in some cases need modifications. In all the cases considered the superconducting phonon structure reflected on the normal side, as well as other structures, shows considerable agreement with experiment as to size, shape, and variation with barrier transmission coefficient. Finally, we study the effects of depairing on these structures

Sources of Variation in Creep Testing

Science.gov (United States)

Loewenthal, William S.; Ellis, David L.

2011-01-01

Creep rupture is an important material characteristic for the design of rocket engines. It was observed during the characterization of GRCop-84 that the complete data set had nearly 4 orders of magnitude of scatter. This scatter likely confounded attempts to determine how creep performance was influenced by manufacturing. It was unclear if this variation was from the testing, the material, or both. Sources of variation were examined by conducting tests on identically processed specimens at the same specified stresses and temperatures. Significant differences existed between the five constant-load creep frames. The specimen temperature was higher than the desired temperature by as much as 43 C. It was also observed that the temperature gradient was up to 44 C. Improved specimen temperature control minimized temperature variations. The data from additional tests demonstrated that the results from all five frames were comparable. The variation decreased to 1/2 order of magnitude from 2 orders of magnitude for the baseline data set. Independent determination of creep rates in a reference load frame closely matched the creep rates determined after the modifications. Testing in helium tended to decrease the sample temperature gradient, but helium was not a significant improvement over vacuum.

Structure & Coupling of Semiotic Sets

Science.gov (United States)

Orsucci, Franco; Giuliani, Alessandro; Zbilut, Joseph

2004-12-01

We investigated the informational structure of written texts (also in the form of speech transcriptions) using Recurrence Quantification Analysis (RQA). RQA technique provides a quantitative description of text sequences at the orthographic level in terms of structuring, and may be useful for a variety of linguistics-related studies. We used RQA to measure differences in linguistic samples from different subjects. They were divided in subgroups based on personality and culture differences. We used RQA and KRQA (Cross Recurrence) to measure the coupling and synchronization during the conversation (semiotic interaction) of different subjects. We discuss results both for the improvement of methodology and some general implications for neurocognitive science.

Temporal and spatial variations in fly ash quality

Science.gov (United States)

Hower, J.C.; Trimble, A.S.; Eble, C.F.

2001-01-01

Fly ash quality, both as the amount of petrographically distinguishable carbons and in chemistry, varies in both time and space. Temporal variations are a function of a number of variables. Variables can include variations in the coal blend organic petrography, mineralogy, and chemistry; variations in the pulverization of the coal, both as a function of the coal's Hardgrove grindability index and as a function of the maintenance and settings of the pulverizers; and variations in the operating conditions of the boiler, including changes in the pollution control system. Spatial variation, as an instantaneous measure of fly ash characteristics, should not involve changes in the first two sets of variables listed above. Spatial variations are a function of the gas flow within the boiler and ducts, certain flow conditions leading to a tendency for segregation of the less-dense carbons in one portion of the gas stream. Caution must be applied in sampling fly ash. Samples from a single bin, or series of bins, m ay not be representative of the whole fly ash, providing a biased view of the nature of the material. Further, it is generally not possible to be certain about variation until the analysis of the ash is complete. ?? 2001 Elsevier Science B.V. All rights reserved.

Set optimization and applications the state of the art : from set relations to set-valued risk measures

CERN Document Server

Heyde, Frank; Löhne, Andreas; Rudloff, Birgit; Schrage, Carola

2015-01-01

This volume presents five surveys with extensive bibliographies and six original contributions on set optimization and its applications in mathematical finance and game theory. The topics range from more conventional approaches that look for minimal/maximal elements with respect to vector orders or set relations, to the new complete-lattice approach that comprises a coherent solution concept for set optimization problems, along with existence results, duality theorems, optimality conditions, variational inequalities and theoretical foundations for algorithms. Modern approaches to scalarization methods can be found as well as a fundamental contribution to conditional analysis. The theory is tailor-made for financial applications, in particular risk evaluation and [super-]hedging for market models with transaction costs, but it also provides a refreshing new perspective on vector optimization. There is no comparable volume on the market, making the book an invaluable resource for researchers working in vector o...

Bifurcation direction and exchange of stability for variational inequalities on nonconvex sets

Czech Academy of Sciences Publication Activity Database

Eisner, Jan; Kučera, Milan; Recke, L.

2007-01-01

Roč. 67, č. 5 (2007), s. 1082-1101 ISSN 0362-546X R&D Projects: GA AV ČR IAA100190506 Institutional research plan: CEZ:AV0Z10190503 Keywords : multiparameter variational inequality * direction of bifurcation * stability of bifurcating solutions Subject RIV: BA - General Mathematics Impact factor: 1.097, year: 2007

Structural lesions detected by magnetic resonance imaging in the spine of patients with spondyloarthritis - definitions, assessment system, and reference image set

DEFF Research Database (Denmark)

Østergaard, Mikkel; Maksymowych, Walter P; Pedersen, Susanne J

2009-01-01

are assessed at each vertebral endplate at all 23 spinal levels from C2/3 to L5/S1, whereas facet joint lesions are to be assessed by segmental level (cervical, thoracic, and lumbar). CONCLUSION: An anatomy-based set of definitions and an assessment system for structural lesions in the spine of patients......OBJECTIVE: There is no reliable and sensitive magnetic resonance imaging (MRI) assessment system for structural lesions in patients with spondyloarthritis (SpA). We sought to develop and illustrate a detailed anatomy-based set of MRI definitions and an assessment system for structural lesions...... in the spine of patients with SpA. METHODS: MRI definitions of different structural ("chronic") lesions at various anatomical locations in the spine, and an accompanying assessment system, were agreed by consensus within the Canada-Denmark MRI working group. Subsequently, a reference image set...

A global reference for human genetic variation

DEFF Research Database (Denmark)

Auton, Adam; Abecasis, Goncalo R.; M. Altshuler, David

2015-01-01

The 1000 Genomes Project set out to provide a comprehensive description of common human genetic variation by applying whole-genome sequencing to a diverse set of individuals from multiple populations. Here we report completion of the project, having reconstructed the genomes of 2,504 individuals ...

Introduction to global variational geometry

CERN Document Server

Krupka, Demeter

2015-01-01

The book is devoted to recent research in the global variational theory on smooth manifolds. Its main objective is an extension of the classical variational calculus on Euclidean spaces to (topologically nontrivial) finite-dimensional smooth manifolds; to this purpose the methods of global analysis of differential forms are used. Emphasis is placed on the foundations of the theory of variational functionals on fibered manifolds - relevant geometric structures for variational principles in geometry, physical field theory and higher-order fibered mechanics. The book chapters include: - foundations of jet bundles and analysis of differential forms and vector fields on jet bundles, - the theory of higher-order integral variational functionals for sections of a fibred space, the (global) first variational formula in infinitesimal and integral forms- extremal conditions and the discussion of Noether symmetries and generalizations,- the inverse problems of the calculus of variations of Helmholtz type- variational se...

Topology optimization of hyperelastic structures using a level set method

Science.gov (United States)

Chen, Feifei; Wang, Yiqiang; Wang, Michael Yu; Zhang, Y. F.

2017-12-01

Soft rubberlike materials, due to their inherent compliance, are finding widespread implementation in a variety of applications ranging from assistive wearable technologies to soft material robots. Structural design of such soft and rubbery materials necessitates the consideration of large nonlinear deformations and hyperelastic material models to accurately predict their mechanical behaviour. In this paper, we present an effective level set-based topology optimization method for the design of hyperelastic structures that undergo large deformations. The method incorporates both geometric and material nonlinearities where the strain and stress measures are defined within the total Lagrange framework and the hyperelasticity is characterized by the widely-adopted Mooney-Rivlin material model. A shape sensitivity analysis is carried out, in the strict sense of the material derivative, where the high-order terms involving the displacement gradient are retained to ensure the descent direction. As the design velocity enters into the shape derivative in terms of its gradient and divergence terms, we develop a discrete velocity selection strategy. The whole optimization implementation undergoes a two-step process, where the linear optimization is first performed and its optimized solution serves as the initial design for the subsequent nonlinear optimization. It turns out that this operation could efficiently alleviate the numerical instability and facilitate the optimization process. To demonstrate the validity and effectiveness of the proposed method, three compliance minimization problems are studied and their optimized solutions present significant mechanical benefits of incorporating the nonlinearities, in terms of remarkable enhancement in not only the structural stiffness but also the critical buckling load.

Solvent micro-evaporation and concentration gradient synergistically induced crystallization of poly(L-lactide) and ring banded supra-structures with radial periodic variation of thickness

DEFF Research Database (Denmark)

Huang, Shaoyong; Li, Hongfei; Wen, Huiying

2014-01-01

The crystalline morphology and structure of poly(L-lactide) (PLLA) in a PLLA film-chloroform system were investigated by means of wide angle X-ray diffraction (WAXD), polarized optical microscopy (POM) and atomic force microscopy (AFM). Birefringent and nonbirefringent ring banded supra-structure......The crystalline morphology and structure of poly(L-lactide) (PLLA) in a PLLA film-chloroform system were investigated by means of wide angle X-ray diffraction (WAXD), polarized optical microscopy (POM) and atomic force microscopy (AFM). Birefringent and nonbirefringent ring banded supra......-structures with radial periodic variation of thickness were obtained, which were induced by micro-evaporation of solvents and concentration gradient of PLLA. The ring banded morphologies consisted of multilayer lamellar crystals, which is a manifestation of alternating ridge and valley bands of periodic variation...

Structure and Function of SET and MYND Domain-Containing Proteins

Directory of Open Access Journals (Sweden)

Nicholas Spellmon

2015-01-01

Full Text Available SET (Suppressor of variegation, Enhancer of Zeste, Trithorax and MYND (Myeloid-Nervy-DEAF1 domain-containing proteins (SMYD have been found to methylate a variety of histone and non-histone targets which contribute to their various roles in cell regulation including chromatin remodeling, transcription, signal transduction, and cell cycle control. During early development, SMYD proteins are believed to act as an epigenetic regulator for myogenesis and cardiomyocyte differentiation as they are abundantly expressed in cardiac and skeletal muscle. SMYD proteins are also of therapeutic interest due to the growing list of carcinomas and cardiovascular diseases linked to SMYD overexpression or dysfunction making them a putative target for drug intervention. This review will examine the biological relevance and gather all of the current structural data of SMYD proteins.

Structural Mimics of the [Fe]-Hydrogenase: A Complete Set for Group VIII Metals.

Science.gov (United States)

Barik, Chandan Kr; Ganguly, Rakesh; Li, Yongxin; Leong, Weng Kee

2018-06-18

A set of structural mimics of the [Fe]-hydrogenase active site comprising all the group VIII metals, viz., [M(2-NHC(O)C 5 H 4 N)(CO) 2 (2-S-C 5 H 4 N)], has been synthesized. They exist as a mixture of isomers in solution, and the relative stability of the isomers depends on the nature of the metal and the substituent at the 6-position of the pyridine ligand.

Study of α-crystallin structure by small-angle neutron scattering with contrast variation

International Nuclear Information System (INIS)

Krivandin, A.V.; Muranov, K.O.; Polyanskij, N.B.; Ostrovskij, M.A.; Murugova, T.N.; Kuklin, A.I.; Aksenov, V.L.

2010-01-01

The structure of the oligomeric protein α-crystallin from the bovine eye lens has been investigated by small-angle neutron scattering (SANS) by the contrast variation method (volume fraction of D 2 O was 0, 23, 68 and 90%). Experiments were carried out on YuMO spectrometer (IBR-2 reactor, JINR). From the SANS curves the match point for α-crystallin (43% D 2 O) and its average scattering length density at this point (2.4·10 10 cm -2 ) have been obtained. The radius of gyration and distance distribution functions for α-crystallin have been calculated as well. On the basis of these calculations it was concluded that α-crystallin has a homogeneous distribution of the scattering density in domains inaccessible for water penetration and all parts of this protein undergo a uniform deuteration. The latter indicates that all α-crystallin subunits have an equal accessibility for water and presumably for some other low molecular weight substances. These conclusions on the α-crystallin structure (a homogeneous distribution of the scattering density and an equal accessibility of all subunits for low molecular weight substances) should be taken into account in the time of elaboration of α-crystallin quaternary structure models

The nonholonomic variational principle

Energy Technology Data Exchange (ETDEWEB)

Krupkova, Olga [Department of Algebra and Geometry, Faculty of Science, Palacky University, Tomkova 40, 779 00 Olomouc (Czech Republic); Department of Mathematics, La Trobe University, Bundoora, Victoria 3086 (Australia)], E-mail: krupkova@inf.upol.cz

2009-05-08

A variational principle for mechanical systems and fields subject to nonholonomic constraints is found, providing Chetaev-reduced equations as equations for extremals. Investigating nonholonomic variations of the Chetaev type and their properties, we develop foundations of the calculus of variations on constraint manifolds, modelled as fibred submanifolds in jet bundles. This setting is appropriate to study general first-order 'nonlinear nonitegrable constraints' that locally are given by a system of first-order ordinary or partial differential equations. We obtain an invariant constrained first variation formula and constrained Euler-Lagrange equations both in intrinsic and coordinate forms, and show that the equations are the same as Chetaev equations 'without Lagrange multipliers', introduced recently by other methods. We pay attention to two possible settings: first, when the constrained system arises from an unconstrained Lagrangian system defined in a neighbourhood of the constraint, and second, more generally, when an 'internal' constrained system on the constraint manifold is given. In the latter case a corresponding unconstrained system need not be a Lagrangian, nor even exist. We also study in detail an important particular case: nonholonomic constraints that can be alternatively modelled by means of (co)distributions in the total space of the fibred manifold; in nonholonomic mechanics this happens whenever constraints affine in velocities are considered. It becomes clear that (and why) if the distribution is completely integrable (= the constraints are semiholonomic), the principle of virtual displacements holds and can be used to obtain the constrained first variational formula by a more or less standard procedure, traditionally used when unconstrained or holonomic systems are concerned. If, however, the constraint is nonintegrable, no significant simplifications are available. Among others, some properties of nonholonomic

Geometric Energy Derivatives at the Complete Basis Set Limit: Application to the Equilibrium Structure and Molecular Force Field of Formaldehyde.

Science.gov (United States)

Morgan, W James; Matthews, Devin A; Ringholm, Magnus; Agarwal, Jay; Gong, Justin Z; Ruud, Kenneth; Allen, Wesley D; Stanton, John F; Schaefer, Henry F

2018-03-13

Geometric energy derivatives which rely on core-corrected focal-point energies extrapolated to the complete basis set (CBS) limit of coupled cluster theory with iterative and noniterative quadruple excitations, CCSDTQ and CCSDT(Q), are used as elements of molecular gradients and, in the case of CCSDT(Q), expansion coefficients of an anharmonic force field. These gradients are used to determine the CCSDTQ/CBS and CCSDT(Q)/CBS equilibrium structure of the S 0 ground state of H 2 CO where excellent agreement is observed with previous work and experimentally derived results. A fourth-order expansion about this CCSDT(Q)/CBS reference geometry using the same level of theory produces an exceptional level of agreement to spectroscopically observed vibrational band origins with a MAE of 0.57 cm -1 . Second-order vibrational perturbation theory (VPT2) and variational discrete variable representation (DVR) results are contrasted and discussed. Vibration-rotation, anharmonicity, and centrifugal distortion constants from the VPT2 analysis are reported and compared to previous work. Additionally, an initial application of a sum-over-states fourth-order vibrational perturbation theory (VPT4) formalism is employed herein, utilizing quintic and sextic derivatives obtained with a recursive algorithmic approach for response theory.

Impact of Implementing a Wiki to Develop Structured Electronic Order Sets on Physicians' Intention to Use Wiki-Based Order Sets.

Science.gov (United States)

Archambault, Patrick Michel; Beaupré, Pierre; Bégin, Laura; Dupuis, Audrey; Côté, Mario; Légaré, France

2016-05-17

Wikis have the potential to promote best practices in health systems by sharing order sets with a broad community of stakeholders. However, little is known about the impact of using a wiki on clinicians' intention to use wiki-based order sets. The aims of this study were: (1) to describe the use of a wiki to create structured order sets for a single emergency department; (2) to evaluate whether the use of this wiki changed emergency physicians' future intention to use wiki-based order sets; and (3) to understand the impact of using the wiki on the behavioral determinants for using wiki-based order sets. This was a pre/post-intervention mixed-methods study conducted in one hospital in Lévis, Quebec. The intervention was comprised of receiving access to and being motivated by the department head to use a wiki for 6 months to create electronic order sets designed to be used in a computer physician order entry system. Before and after our intervention, we asked participants to complete a previously validated questionnaire based on the Theory of Planned Behavior. Our primary outcome was the intention to use wiki-based order sets in clinical practice. We also assessed participants' attitude, perceived behavioral control, and subjective norm to use wiki-based order sets. Paired pre- and post-Likert scores were compared using Wilcoxon signed-rank tests. The post-questionnaire also included open-ended questions concerning participants' comments about the wiki, which were then classified into themes using an existing taxonomy. Twenty-eight emergency physicians were enrolled in the study (response rate: 100%). Physicians' mean intention to use a wiki-based reminder was 5.42 (SD 1.04) before the intervention, and increased to 5.81 (SD 1.25) on a 7-point Likert scale (P =.03) after the intervention. Participants' attitude towards using a wiki-based order set also increased from 5.07 (SD 0.90) to 5.57 (SD 0.88) (P =.003). Perceived behavioral control and subjective norm did not

Structure of Lie point and variational symmetry algebras for a class of odes

Science.gov (United States)

Ndogmo, J. C.

2018-04-01

It is known for scalar ordinary differential equations, and for systems of ordinary differential equations of order not higher than the third, that their Lie point symmetry algebras is of maximal dimension if and only if they can be reduced by a point transformation to the trivial equation y(n)=0. For arbitrary systems of ordinary differential equations of order n ≥ 3 reducible by point transformations to the trivial equation, we determine the complete structure of their Lie point symmetry algebras as well as that for their variational, and their divergence symmetry algebras. As a corollary, we obtain the maximal dimension of the Lie point symmetry algebra for any system of linear or nonlinear ordinary differential equations.

Lidar observed seasonal variation of vertical canopy structure in the Amazon evergreen forests

Science.gov (United States)

Tang, H.; Dubayah, R.

2017-12-01

Both light and water are important environmental factors governing tree growth. Responses of tropical forests to their changes are complicated and can vary substantially across different spatial and temporal scales. Of particular interest is the dry-season greening-up of Amazon forests, a phenomenon undergoing considerable debates whether it is real or a "light illusion" caused by artifacts of passive optical remote sensing techniques. Here we analyze seasonal dynamic patterns of vertical canopy structure in the Amazon forests using lidar observations from NASA's Ice, Cloud, and and land Elevation Satellite (ICESat). We found that the net greening of canopy layer coincides with the wet-to-dry transition period, and its net browning occurs mostly at the late dry season. The understory also shows a seasonal cycle, but with an opposite variation to canopy and minimal correlation to seasonal variations in rainfall or radiation. Our results further suggest a potential interaction between canopy layers in the light regime that can optimize the growth of Amazon forests during the dry season. This light regime variability that exists in both spatial and temporal domains can better reveal the dry-season greening-up phenomenon, which appears less obvious when treating the Amazon forests as a whole.

Level Set Structure of an Integrable Cellular Automaton

Directory of Open Access Journals (Sweden)

Taichiro Takagi

2010-03-01

Full Text Available Based on a group theoretical setting a sort of discrete dynamical system is constructed and applied to a combinatorial dynamical system defined on the set of certain Bethe ansatz related objects known as the rigged configurations. This system is then used to study a one-dimensional periodic cellular automaton related to discrete Toda lattice. It is shown for the first time that the level set of this cellular automaton is decomposed into connected components and every such component is a torus.

POF based smart sensor for studying the setting dynamics of cement paste

International Nuclear Information System (INIS)

Rajesh, M; Sheeba, M; Nampoori, V P N

2007-01-01

Fiber optic smart sensors are used to monitor the civil structures. One of the important parameters in civil engineering is the setting characteristics of concrete made of cement. The paper discusses how a simple polymer optical fiber can be used to characterise the setting dynamics of various grades of cement. The results explain the comparative performance of polymer fiber over silica fiber. The basic principle underlying the sensor is that as the cement sets, it exerts a stress on the sensing fiber, which is laid within the cement paste. This stress induces strain on the optical fiber, which can be thought of as a series of aperiodic microbends on the surface of the fiber. This in turn changes the characteristics of the light signal transmitted through the fiber and can be viewed as stress induced modulation of light in the fiber. By monitoring the intensity variation of transmitted light signal with time we can determine the cement setting rate. This can be used as an effective tool for quality testing of commercially available cements of different grades

Variational approach in transport theory

International Nuclear Information System (INIS)

Panta Pazos, R.; Tullio de Vilhena, M.

2004-01-01

In this work we present a variational approach to some methods to solve transport problems of neutral particles. We consider a convex domain X (for example the geometry of a slab, or a convex set in the plane, or a convex bounded set in the space) and we use discrete ordinates quadrature to get a system of differential equations derived from the neutron transport equation. The boundary conditions are vacuum for a subset of the boundary, and of specular reflection for the complementary subset of the boundary. Recently some different approximation methods have been presented to solve these transport problems. We introduce in this work the adjoint equations and the conjugate functions obtained by means of the variational approach. First we consider the general formulation, and then some numerical methods such as spherical harmonics and spectral collocation method. (authors)

Variational approach in transport theory

Energy Technology Data Exchange (ETDEWEB)

Panta Pazos, R. [Nucler Engineering Department, UFRGS, Porto-Alegre (Brazil); Tullio de Vilhena, M. [Institute of Mathematics, UFRGS, Porto-Alegre (Brazil)

2004-07-01

In this work we present a variational approach to some methods to solve transport problems of neutral particles. We consider a convex domain X (for example the geometry of a slab, or a convex set in the plane, or a convex bounded set in the space) and we use discrete ordinates quadrature to get a system of differential equations derived from the neutron transport equation. The boundary conditions are vacuum for a subset of the boundary, and of specular reflection for the complementary subset of the boundary. Recently some different approximation methods have been presented to solve these transport problems. We introduce in this work the adjoint equations and the conjugate functions obtained by means of the variational approach. First we consider the general formulation, and then some numerical methods such as spherical harmonics and spectral collocation method. (authors)

A comparative study of set up variations and bowel volumes in supine versus prone positions of patients treated with external beam radiation for carcinoma rectum.

Science.gov (United States)

Rajeev, K R; Menon, Smrithy S; Beena, K; Holla, Raghavendra; Kumar, R Rajaneesh; Dinesh, M

2014-01-01

A prospective study was undertaken to evaluate the influence of patient positioning on the set up variations to determine the planning target volume (PTV) margins and to evaluate the clinical relevance volume assessment of the small bowel (SB) within the irradiated volume. During the period of months from December 2011 to April 2012, a computed tomography (CT) scan was done either in supine position or in prone position using a belly board (BB) for 20 consecutive patients. All the patients had histologically proven rectal cancer and received either post- or pre-operative pelvic irradiation. Using a three-dimensional planning system, the dose-volume histogram for SB was defined in each axial CT slice. Total dose was 46-50 Gy (2 Gy/fraction), delivered using the 4-field box technique. The set up variation of the study group was assessed from the data received from the electronic portal imaging device in the linear accelerator. The shift along X, Y, and Z directions were noted. Both systematic and random errors were calculated and using both these values the PTV margin was calculated. The systematic errors of patients treated in the supine position were 0.87 (X-mm), 0.66 (Y-mm), 1.6 (Z-mm) and in the prone position were 1.3 (X-mm), 0.59 (Y-mm), 1.17 (Z-mm). The random errors of patients treated in the supine positions were 1.81 (X-mm), 1.73 (Y-mm), 1.83 (Z-mm) and in prone position were 2.02 (X-mm), 1.21 (Y-mm), 3.05 (Z-mm). The calculated PTV margins in the supine position were 3.45 (X-mm), 2.87 (Y-mm), 5.31 (Z-mm) and in the prone position were 4.91 (X-mm), 2.32 (Y-mm), 5.08 (Z-mm). The mean volume of the peritoneal cavity was 648.65 cm 3 in the prone position and 1197.37 cm 3 in the supine position. The prone position using BB device was more effective in reducing irradiated SB volume in rectal cancer patients. There were no significant variations in the daily set up for patients treated in both supine and prone positions.

Prediction of individual differences in risky behavior in young adults via variations in local brain structure

Science.gov (United States)

Nasiriavanaki, Zahra; ArianNik, Mohsen; Abbassian, Abdolhosein; Mahmoudi, Elham; Roufigari, Neda; Shahzadi, Sohrab; Nasiriavanaki, Mohammadreza; Bahrami, Bahador

2015-01-01

In recent years the problem of how inter-individual differences play a role in risk-taking behavior has become a much debated issue. We investigated this problem based on the well-known balloon analog risk task (BART) in 48 healthy subjects in which participants inflate a virtual balloon opting for a higher score in the face of a riskier chance of the balloon explosion. In this study, based on a structural Voxel Based Morphometry (VBM) technique we demonstrate a significant positive correlation between BART score and size of the gray matter volume in the anterior insula in riskier subjects. Although the anterior insula is among the candidate brain areas that were involved in the risk taking behavior in fMRI studies, here based on our structural data it is the only area that was significantly related to structural variation among different subjects. PMID:26500482

Seasonal and spatial variations in fish and macrocrustacean assemblage structure in Mad Island Marsh estuary, Texas

Science.gov (United States)

Akin, S.; Winemiller, K. O.; Gelwick, F. P.

2003-05-01

Fish and macrocrustacean assemblage structure was analyzed along an estuarine gradient at Mad Island Marsh (MIM), Matagorda Bay, TX, during March 1998-August 1999. Eight estuarine-dependent fish species accounted for 94% of the individual fishes collected, and three species accounted for 96% of macrocrustacean abundance. Consistent with evidence from other Gulf of Mexico estuarine studies, species richness and abundance were highest during late spring and summer, and lowest during winter and early spring. Sites near the bay supported the most individuals and species. Associations between fish abundance and environmental variables were examined with canonical correspondence analysis. The dominant gradient was associated with water depth and distance from the bay. The secondary gradient reflected seasonal variation and was associated with temperature, salinity, dissolved oxygen, and vegetation cover. At the scales examined, estuarine biota responded to seasonal variation more than spatial variation. Estuarine-dependent species dominated the fauna and were common throughout the open waters of the shallow lake during winter-early spring when water temperature and salinity were low and dissolved oxygen high. During summer-early fall, sub-optimal environmental conditions (high temperature, low DO) in upper reaches accounted for strong spatial variation in assemblage composition. Small estuarine-resident fishes and the blue crab ( Callinectes sapidus) were common in warm, shallow, vegetated inland sites during summer-fall. Estuarine-dependent species were common at deeper, more saline locations near the bay during this period. During summer, freshwater species, such as gizzard shad ( Dorosoma cepedianum) and gars ( Lepisosteus spp.), were positively associated with water depth and proximity to the bay. The distribution and abundance of fishes in MIM appear to result from the combined effects of endogenous, seasonal patterns of reproduction and migration operating on large

Using natural range of variation to set decision thresholds: a case study for great plains grasslands

Science.gov (United States)

Symstad, Amy J.; Jonas, Jayne L.; Edited by Guntenspergen, Glenn R.

2014-01-01

Natural range of variation (NRV) may be used to establish decision thresholds or action assessment points when ecological thresholds are either unknown or do not exist for attributes of interest in a managed ecosystem. The process for estimating NRV involves identifying spatial and temporal scales that adequately capture the heterogeneity of the ecosystem; compiling data for the attributes of interest via study of historic records, analysis and interpretation of proxy records, modeling, space-for-time substitutions, or analysis of long-term monitoring data; and quantifying the NRV from those data. At least 19 National Park Service (NPS) units in North America’s Great Plains are monitoring plant species richness and evenness as indicators of vegetation integrity in native grasslands, but little information on natural, temporal variability of these indicators is available. In this case study, we use six long-term vegetation monitoring datasets to quantify the temporal variability of these attributes in reference conditions for a variety of Great Plains grassland types, and then illustrate the implications of using different NRVs based on these quantities for setting management decision thresholds. Temporal variability of richness (as measured by the coefficient of variation, CV) is fairly consistent across the wide variety of conditions occurring in Colorado shortgrass prairie to Minnesota tallgrass sand savanna (CV 0.20–0.45) and generally less than that of production at the same sites. Temporal variability of evenness spans a greater range of CV than richness, and it is greater than that of production in some sites but less in other sites. This natural temporal variability may mask undesirable changes in Great Plains grasslands vegetation. Consequently, we suggest that managers consider using a relatively narrow NRV (interquartile range of all richness or evenness values observed in reference conditions) for designating a surveillance threshold, at which

Smart variations: Functional substructures for part compatibility

KAUST Repository

Zheng, Youyi

2013-05-01

As collections of 3D models continue to grow, reusing model parts allows generation of novel model variations. Naïvely swapping parts across models, however, leads to implausible results, especially when mixing parts across different model families. Hence, the user has to manually ensure that the final model remains functionally valid. We claim that certain symmetric functional arrangements (sFarr-s), which are special arrangements among symmetrically related substructures, bear close relation to object functions. Hence, we propose a purely geometric approach based on such substructures to match, replace, and position triplets of parts to create non-trivial, yet functionally plausible, model variations. We demonstrate that starting even from a small set of models such a simple geometric approach can produce a diverse set of non-trivial and plausible model variations. © 2013 The Author(s) Computer Graphics Forum © 2013 The Eurographics Association and Blackwell Publishing Ltd.

Nanostructured and nanolayer coatings based on nitrides of the metals structure study and structure and composition standard samples set development

Directory of Open Access Journals (Sweden)

E. B. Chabina

2014-01-01

Full Text Available Researches by methods of analytical microscopy and the x-ray analysis have allowed to develop a set of standard samples of composition and structure of the strengthening nanostructured and nanolayer coatings for control of the strengthening nanostructured and nanolayer coatings based on nitrides of the metals used to protect critical parts of the compressor of the gas turbine engine from dust erosion, corrosion and oxidation.

Basis set construction for molecular electronic structure theory: natural orbital and Gauss-Slater basis for smooth pseudopotentials.

Science.gov (United States)

Petruzielo, F R; Toulouse, Julien; Umrigar, C J

2011-02-14

A simple yet general method for constructing basis sets for molecular electronic structure calculations is presented. These basis sets consist of atomic natural orbitals from a multiconfigurational self-consistent field calculation supplemented with primitive functions, chosen such that the asymptotics are appropriate for the potential of the system. Primitives are optimized for the homonuclear diatomic molecule to produce a balanced basis set. Two general features that facilitate this basis construction are demonstrated. First, weak coupling exists between the optimal exponents of primitives with different angular momenta. Second, the optimal primitive exponents for a chosen system depend weakly on the particular level of theory employed for optimization. The explicit case considered here is a basis set appropriate for the Burkatzki-Filippi-Dolg pseudopotentials. Since these pseudopotentials are finite at nuclei and have a Coulomb tail, the recently proposed Gauss-Slater functions are the appropriate primitives. Double- and triple-zeta bases are developed for elements hydrogen through argon. These new bases offer significant gains over the corresponding Burkatzki-Filippi-Dolg bases at various levels of theory. Using a Gaussian expansion of the basis functions, these bases can be employed in any electronic structure method. Quantum Monte Carlo provides an added benefit: expansions are unnecessary since the integrals are evaluated numerically.

Geographic structure of genetic variation in the widespread woodland grass Milium effusum L. A comparison between two regions with contrasting history and geomorphology.

Science.gov (United States)

Tyler, Torbjörn

2002-12-01

Allozyme variation in the forest grass Milium effusum L. was studied in 21-23 populations within each of two equally sized densely sampled areas in northern and southern Sweden. In addition, 25 populations from other parts of Eurasia were studied for comparison. The structure of variation was analysed with both diversity statistics and measures based on allelic richness at a standardised sample size. The species was found to be highly variable, but no clear geographic patterns in the distribution of alleles or in overall genetic differentiation were found, either within the two regions or within the whole sample. Thus, no inferences about the direction of postglacial migration could be made. Obviously, migration and gene flow must have taken place in a manner capable of randomising the distribution of alleles. However, there were clear differences in levels and structuring of the variation between the two regions. Levels of variation, both in terms of genetic diversity and allelic richness, were lower in northern Sweden as compared with southern Sweden. In contrast, different measures of geographic structure all showed higher levels of population differentiation in the northern region. This is interpreted as due to different geomorphological conditions in the two regions, creating a relatively continuous habitat and gene flow in the southern region as compared with the northern region where the species, although common, is confined to narrow and mutually isolated corridors in the landscape.

Variations of extreme rainfall in space and time

DEFF Research Database (Denmark)

Gregersen, Ida Bülow; Madsen, H.; Rosbjerg, Dan

2012-01-01

variation, whereas annual variations are related to changes in the average Danish summer precipitation, the average Danish summer temperature and the East Atlantic pattern. The spatio-temporal Poisson regression model was found to be a helpful tool when comparing the internal importance of these variables......In the ongoing climate change discussion, methods for identification of variability governed by climate change are important tools. The magnitude of variables that can describe this variability should be compared with magnitudes of variables describing variability in a stationary setting....... This study focuses on variations of extreme rainfall events, observed at 70 different locations in Denmark over a period of 31 years. The aim is to identify and compare variables, both spatially and temporally, which can explain different parts of the variability in this data set. Assuming that the number...

Structural stigma and the health and wellbeing of Australian LGB populations: Exploiting geographic variation in the results of the 2017 same-sex marriage plebiscite.

Science.gov (United States)

Perales, Francisco; Todd, Abram

2018-05-14

Lesbian, gay, or bisexual (LGB) people experience poorer life outcomes than heterosexual people, with ongoing debates about the aetiology of these differences. Minority stress theory draws attention to the importance of structural stigma, which concerns hostile social environments for sexual minorities that constrain their opportunity structures. Yet few studies have operationalised structural stigma and tested its influence, with most focusing on the US context; even fewer studies examine the underlying mechanisms. This study expands the available evidence to Australia, which constitutes an interesting case study due to the implementation in late 2017 of a national postal plebiscite on same-sex marriage legislation. It also adds to knowledge by theorising and testing the mediating role of perceived social support in explaining the association between structural stigma and the life outcomes of LGB people. The analyses leverage geographical variation at the electorate level (n = 150) in the share of 'No' voters in the plebiscite as a measure of structural stigma. This aggregate-level information is merged to individual-level data from the Household, Income and Labour Dynamics in Australia Survey, a large, national probability sample (n∽15,000). Multilevel regression models yield results which are consistent with minority stress theory and previous US scholarship: LGB people report comparatively worse life satisfaction, mental health and overall health in constituencies with higher shares of 'No' voters, controlling for a large set of individual- and aggregate-level confounds. Perceived social support mediates a large portion of the effects of structural stigma on LGB outcomes. These findings have significant implications for policy and practice, highlighting the need for interventions aimed at reducing community levels of structural stigma and increasing social support to LGB populations. Copyright © 2018 Elsevier Ltd. All rights reserved.

Structural Variation within the Amygdala and Ventromedial Prefrontal Cortex Predict Memory for Impressions in Older Adults

Directory of Open Access Journals (Sweden)

Brittany Shane Cassidy

2012-08-01

Full Text Available Research has shown that lesions to regions involved in social and emotional cognition disrupt socioemotional processing and memory. We investigated how structural variation of regions involved in socioemotional memory (ventromedial prefrontal cortex [vmPFC], amygdala, as opposed to a region implicated in explicit memory (hippocampus, affected memory for impressions in young and older adults. Anatomical MRI scans for fifteen young and fifteen older adults were obtained and reconstructed to gather information about cortical thickness and subcortical volume. Young adults had greater amygdala and hippocampus volumes than old, and thicker left vmPFC than old, although right vmPFC thickness did not differ across the age groups. Participants formed behavior-based impressions and responded to interpersonally meaningful, social but interpersonally irrelevant, or non-social prompts, and completed a memory test. Results showed that greater left amygdala volume predicted enhanced overall memory for impressions in older but not younger adults. Increased right vmPFC thickness in older, but not younger, adults correlated with enhanced memory for impressions formed in the interpersonally meaningful context. Hippocampal volume was not predictive of social memory in young or older adults. These findings demonstrate the importance of structural variation in regions linked to socioemotional processing in the retention of impressions with age, and suggest that the amygdala and vmPFC play an integral role when encoding and retrieving social information.

Managing Information Uncertainty in Wave Height Modeling for the Offshore Structural Analysis through Random Set

Directory of Open Access Journals (Sweden)

Keqin Yan

2017-01-01

Full Text Available This chapter presents a reliability study for an offshore jacket structure with emphasis on the features of nonconventional modeling. Firstly, a random set model is formulated for modeling the random waves in an ocean site. Then, a jacket structure is investigated in a pushover analysis to identify the critical wave direction and key structural elements. This is based on the ultimate base shear strength. The selected probabilistic models are adopted for the important structural members and the wave direction is specified in the weakest direction of the structure for a conservative safety analysis. The wave height model is processed in a P-box format when it is used in the numerical analysis. The models are applied to find the bounds of the failure probabilities for the jacket structure. The propagation of this wave model to the uncertainty in results is investigated in both an interval analysis and Monte Carlo simulation. The results are compared in context of information content and numerical accuracy. Further, the failure probability bounds are compared with the conventional probabilistic approach.

Frontiers of higher order fuzzy sets

CERN Document Server

Tahayori, Hooman

2015-01-01

Frontiers of Higher Order Fuzzy Sets, strives to improve the theoretical aspects of general and Interval Type-2 fuzzy sets and provides a unified representation theorem for higher order fuzzy sets. Moreover, the book elaborates on the concept of gradual elements and their integration with the higher order fuzzy sets. This book also introduces new frameworks for information granulation based on general T2FSs, IT2FSs, Gradual elements, Shadowed sets and rough sets. In particular, the properties and characteristics of the new proposed frameworks are studied. Such new frameworks are shown to be more capable to be exploited in real applications. Higher order fuzzy sets that are the result of the integration of general T2FSs, IT2FSs, gradual elements, shadowed sets and rough sets will be shown to be suitable to be applied in the fields of bioinformatics, business, management, ambient intelligence, medicine, cloud computing and smart grids. Presents new variations of fuzzy set frameworks and new areas of applicabili...

A map of human genome variation from population-scale sequencing.

Science.gov (United States)

Abecasis, Gonçalo R; Altshuler, David; Auton, Adam; Brooks, Lisa D; Durbin, Richard M; Gibbs, Richard A; Hurles, Matt E; McVean, Gil A

2010-10-28

The 1000 Genomes Project aims to provide a deep characterization of human genome sequence variation as a foundation for investigating the relationship between genotype and phenotype. Here we present results of the pilot phase of the project, designed to develop and compare different strategies for genome-wide sequencing with high-throughput platforms. We undertook three projects: low-coverage whole-genome sequencing of 179 individuals from four populations; high-coverage sequencing of two mother-father-child trios; and exon-targeted sequencing of 697 individuals from seven populations. We describe the location, allele frequency and local haplotype structure of approximately 15 million single nucleotide polymorphisms, 1 million short insertions and deletions, and 20,000 structural variants, most of which were previously undescribed. We show that, because we have catalogued the vast majority of common variation, over 95% of the currently accessible variants found in any individual are present in this data set. On average, each person is found to carry approximately 250 to 300 loss-of-function variants in annotated genes and 50 to 100 variants previously implicated in inherited disorders. We demonstrate how these results can be used to inform association and functional studies. From the two trios, we directly estimate the rate of de novo germline base substitution mutations to be approximately 10(-8) per base pair per generation. We explore the data with regard to signatures of natural selection, and identify a marked reduction of genetic variation in the neighbourhood of genes, due to selection at linked sites. These methods and public data will support the next phase of human genetic research.

Variational integrators for electric circuits

International Nuclear Information System (INIS)

Ober-Blöbaum, Sina; Tao, Molei; Cheng, Mulin; Owhadi, Houman; Marsden, Jerrold E.

2013-01-01

In this contribution, we develop a variational integrator for the simulation of (stochastic and multiscale) electric circuits. When considering the dynamics of an electric circuit, one is faced with three special situations: 1. The system involves external (control) forcing through external (controlled) voltage sources and resistors. 2. The system is constrained via the Kirchhoff current (KCL) and voltage laws (KVL). 3. The Lagrangian is degenerate. Based on a geometric setting, an appropriate variational formulation is presented to model the circuit from which the equations of motion are derived. A time-discrete variational formulation provides an iteration scheme for the simulation of the electric circuit. Dependent on the discretization, the intrinsic degeneracy of the system can be canceled for the discrete variational scheme. In this way, a variational integrator is constructed that gains several advantages compared to standard integration tools for circuits; in particular, a comparison to BDF methods (which are usually the method of choice for the simulation of electric circuits) shows that even for simple LCR circuits, a better energy behavior and frequency spectrum preservation can be observed using the developed variational integrator

A variational proof of Thomson's theorem

Energy Technology Data Exchange (ETDEWEB)

Fiolhais, Miguel C.N., E-mail: miguel.fiolhais@cern.ch [Department of Physics, City College of the City University of New York, 160 Convent Avenue, New York, NY 10031 (United States); Department of Physics, New York City College of Technology, 300 Jay Street, Brooklyn, NY 11201 (United States); LIP, Department of Physics, University of Coimbra, 3004-516 Coimbra (Portugal); Essén, Hanno [Department of Mechanics, Royal Institute of Technology (KTH), Stockholm SE-10044 (Sweden); Gouveia, Tomé M. [Cavendish Laboratory, 19 JJ Thomson Avenue, Cambridge CB3 0HE (United Kingdom)

2016-08-12

Thomson's theorem of electrostatics, which states the electric charge on a set of conductors distributes itself on the conductor surfaces to minimize the electrostatic energy, is reviewed in this letter. The proof of Thomson's theorem, based on a variational principle, is derived for a set of normal charged conductors, with and without the presence of external electric fields produced by fixed charge distributions. In this novel approach, the variations are performed on both the charge densities and electric potentials, by means of a local Lagrange multiplier associated with Poisson's equation, constraining the two variables.

Spatio-temporal variations in phytoplankton community structure in ...

African Journals Online (AJOL)

OMARI

2013-09-06

Sep 6, 2013 ... estimating potential fish yield (Descy et al., 2005), .... populations have been conducted in open waters Lake ... Victoria basin Kenya which was stratified in terms of altitude .... Mean monthly variation of surface water pH values in small water bodies ..... Although there was optimal temperature, pH, D.O.

Validation of Accelerometer-Based Energy Expenditure Prediction Models in Structured and Simulated Free-Living Settings

Science.gov (United States)

Montoye, Alexander H. K.; Conger, Scott A.; Connolly, Christopher P.; Imboden, Mary T.; Nelson, M. Benjamin; Bock, Josh M.; Kaminsky, Leonard A.

2017-01-01

This study compared accuracy of energy expenditure (EE) prediction models from accelerometer data collected in structured and simulated free-living settings. Twenty-four adults (mean age 45.8 years, 50% female) performed two sessions of 11 to 21 activities, wearing four ActiGraph GT9X Link activity monitors (right hip, ankle, both wrists) and a…

Along Arc Structural Variation in the Izu-Bonin Arc and its Implications for Crustal Evolution Processes

Science.gov (United States)

Kodaira, S.; Sato, T.; Takahashi, N.; Ito, A.; Kaneda, Y.

2005-12-01

A continental-type middle crust having Vp = 6.1 - 6.3 km/s has been imaged at several oceanic island arcs (e.g. northern Izu, Mariana, Tonga, Kyushu-Palau ridge) since Suyehiro et al. (1996) has found a felsic middle crust in the northern Izu arc. A high velocity lower crust (Vp > 7.3 km/s) underlying the felsic middle crust has been also underlined as a characteristic structure in the northern Izu arc. A bulk composition of the crust in the Izu arc may indicate more mafic than that of a typical continental crust due to a large volume of the high velocity lower crust. Since a crust becomes more mature toward the north along the Izu-Bonin arc, investigating structural variation along the volcanic front has been believed to provide a fundamental knowledge for a crustal evolution process. In 2004 and 2005, Japan Agency for Marine-Earth Science and Technology has conducted two along arc wide-angle seismic surveys from the Sagami-bay to the Kita-Iwo jima, a total profile length of about 1000 km. Although data from the Bonin-part of the profile which were acquired this year has not been processed yet, a result from the Izu-part, from the Sagami-bay to Tori shima, shows significant structural variations along the volcanic front. The crustal thickness are varied with a wavelength of several tens of km, i.e., thickened up to 25-30 km around the volcanoes (the Miyake jama, Hachijo jima, Aoga sima, Sumisu jima), while thinned down to 20 km between them. The fine seismic velocity image obtained by refraction tomography as well as a wide-angle reflection migration shows that the variation of the crustal block having 6.0 - 6.7 km/s, which is a typical continental crustal velocity, is mainly responsible for the observed variation of the crustal thickness. The thickness of the high velocity lower crust is not significantly varied along the arc. Therefore, an average crustal seismic velocity (varied 6.6 to 7.0 km/s) represents a higher velocity that that of a typical continental

Genomic structural variation contributes to phenotypic change of industrial bioethanol yeast Saccharomyces cerevisiae.

Science.gov (United States)

Zhang, Ke; Zhang, Li-Jie; Fang, Ya-Hong; Jin, Xin-Na; Qi, Lei; Wu, Xue-Chang; Zheng, Dao-Qiong

2016-03-01

Genomic structural variation (GSV) is a ubiquitous phenomenon observed in the genomes of Saccharomyces cerevisiae strains with different genetic backgrounds; however, the physiological and phenotypic effects of GSV are not well understood. Here, we first revealed the genetic characteristics of a widely used industrial S. cerevisiae strain, ZTW1, by whole genome sequencing. ZTW1 was identified as an aneuploidy strain and a large-scale GSV was observed in the ZTW1 genome compared with the genome of a diploid strain YJS329. These GSV events led to copy number variations (CNVs) in many chromosomal segments as well as one whole chromosome in the ZTW1 genome. Changes in the DNA dosage of certain functional genes directly affected their expression levels and the resultant ZTW1 phenotypes. Moreover, CNVs of large chromosomal regions triggered an aneuploidy stress in ZTW1. This stress decreased the proliferation ability and tolerance of ZTW1 to various stresses, while aneuploidy response stress may also provide some benefits to the fermentation performance of the yeast, including increased fermentation rates and decreased byproduct generation. This work reveals genomic characters of the bioethanol S. cerevisiae strain ZTW1 and suggests that GSV is an important kind of mutation that changes the traits of industrial S. cerevisiae strains. © FEMS 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Exploring Duopoly Markets with Conjectural Variations

Science.gov (United States)

Julien, Ludovic A.; Musy, Olivier; Saïdi, Aurélien W.

2014-01-01

In this article, the authors investigate competitive firm behaviors in a two-firm environment assuming linear cost and demand functions. By introducing conjectural variations, they capture the different market structures as specific configurations of a more general model. Conjectural variations are based on the assumption that each firm believes…

Seasonal variation in sports participation.

Science.gov (United States)

Schüttoff, Ute; Pawlowski, Tim

2018-02-01

This study explores indicators describing socio-demographics, sports participation characteristics and motives which are associated with variation in sports participation across seasons. Data were drawn from the German Socio-Economic Panel which contains detailed information on the sports behaviour of adults in Germany. Overall, two different measures of seasonal variation are developed and used as dependent variables in our regression models. The first variable measures the coefficient of (seasonal) variation in sport-related energy expenditure per week. The second variable measures whether activity drops below the threshold as defined by the World Health Organization (WHO). Results suggest that the organisational setting, the intensity and number of sports practised, and the motive for participation are strongly correlated with the variation measures used. For example, both, participation in a sports club and a commercial facility, are associated with reduced seasonal variation and a significantly higher probability of participating at a volume above the WHO threshold across all seasons. These findings give some impetus for policymaking and the planning of sports programmes as well as future research directions.

Mangrove forests submitted to depositional processes and salinity variation investigated using satellite images and vegetation structure surveys

OpenAIRE

Cunha-Lignon, M.; Kampel, M.; Menghini, R.P.; Schaeffer-Novelli, Y.; Cintrón, G.; Dahdouh-Guebas, F.

2011-01-01

The current paper examines the growth and spatio-temporal variation of mangrove forests in response to depositional processes and different salinity conditions. Data from mangrove vegetation structure collected at permanent plots and satellite images were used. In the northern sector important environmental changes occurred due to an artificial channel producing modifications in salinity. The southern sector is considered the best conserved mangrove area along the coast of São Paulo State, Br...

Matter tensor from the Hilbert variational principle

International Nuclear Information System (INIS)

Pandres, D. Jr.

1976-01-01

We consider the Hilbert variational principle which is conventionally used to derive Einstein's equations for the source-free gravitational field. We show that at least one version of the equivalence principle suggests an alternative way of performing the variation, resulting in a different set of Einstein equations with sources automatically present. This illustrates a technique which may be applied to any theory that is derived from a variational principle and that admits a gauge group. The essential point is that, if one first imposes a gauge condition and then performs the variation, one obtains field equations with source terms which do not appear if one first performs the variation and then imposes the gauge condition. A second illustration is provided by the variational principle conventionally used to derive Maxwell's equations for the source-free electromagnetic field. If one first imposes the Lorentz gauge condition and then performs the variation, one obtains Maxwell's equations with sources present

Electronic structure simulation of chromium aluminum oxynitride by discrete variational-Xα method and X-ray photoelectron spectroscopy

International Nuclear Information System (INIS)

Choi, Youngmin; Chang, Hyunju; Lee, Jae Do; Kim, Eunah; No, Kwangsoo

2002-01-01

We use a first-principles discrete variational (DV)-Xα method to investigate the electronic structure of chromium aluminum oxynitride. When nitrogen is substituted for oxygen in the Cr-Al-O system, the N2p level appears in the energy range between O2p and Cr3d levels. Consequently, the valence band of chromium aluminum oxynitride becomes broader and the band gap becomes smaller than that of chromium aluminum oxide, which is consistent with the photoelectron spectra for the valence band using X-ray photoelectron spectroscopy (XPS) and ultraviolet photoelectron spectroscopy (UPS). We expect that this valence band structure of chromium aluminum oxynitride will modify the transmittance slope which is a requirement for photomask application. (author)

Anomalous singularities in the complex Kohn variational principle of quantum scattering theory

International Nuclear Information System (INIS)

Lucchese, R.R.

1989-01-01

Variational principles for symmetric complex scattering matrices (e.g., the S matrix or the T matrix) based on the Kohn variational principle have been thought to be free from anomalous singularities. We demonstrate that singularities do exist for these variational principles by considering single and multichannel model problems based on exponential interaction potentials. The singularities are found by considering simultaneous variations in two nonlinear parameters in the variational calculation (e.g., the energy and the cutoff function for the irregular continuum functions). The singularities are found when the cutoff function for the irregular continuum functions extends over a range of the radial coordinate where the square-integrable basis set does not have sufficient flexibility. Effects of these singularities generally should not appear in applications of the complex Kohn method where a fixed variational basis set is considered and only the energy is varied

Effect of α variation on a prospective experiment to detect variation of me/mp in diatomic molecules

International Nuclear Information System (INIS)

Beloy, K.; Borschevsky, A.; Schwerdtfeger, P.; Flambaum, V. V.

2011-01-01

We consider the influence of variation in the fine structure constant α on a promising experiment proposed by DeMille et al. to search for variation in the electron-to-proton mass ratio μ using diatomic molecules [DeMille et al., Phys. Rev. Lett. 100, 043202 (2008)]. The proposed experiment involves spectroscopically probing the splitting between two nearly degenerate vibrational levels supported by different electronic potentials. Here we demonstrate that this splitting may be equally or more sensitive to variation in α as to variation in μ. For the anticipated experimental precision, this implies that the α variation may not be negligible, as previously assumed, and further suggests that the method could serve as a competitive means to search for α variation as well.

Spatial variation in the parasite communities and genomic structure of urban rats in New York City.

Science.gov (United States)

Angley, L P; Combs, M; Firth, C; Frye, M J; Lipkin, I; Richardson, J L; Munshi-South, J

2018-02-01

Brown rats (Rattus norvegicus) are a globally distributed pest. Urban habitats can support large infestations of rats, posing a potential risk to public health from the parasites and pathogens they carry. Despite the potential influence of rodent-borne zoonotic diseases on human health, it is unclear how urban habitats affect the structure and transmission dynamics of ectoparasite and microbial communities (all referred to as "parasites" hereafter) among rat colonies. In this study, we use ecological data on parasites and genomic sequencing of their rat hosts to examine associations between spatial proximity, genetic relatedness and the parasite communities associated with 133 rats at five sites in sections of New York City with persistent rat infestations. We build on previous work showing that rats in New York carry a wide variety of parasites and report that these communities differ significantly among sites, even across small geographical distances. Ectoparasite community similarity was positively associated with geographical proximity; however, there was no general association between distance and microbial communities of rats. Sites with greater overall parasite diversity also had rats with greater infection levels and parasite species richness. Parasite community similarity among sites was not linked to genetic relatedness of rats, suggesting that these communities are not associated with genetic similarity among host individuals or host dispersal among sites. Discriminant analysis identified site-specific associations of several parasite species, suggesting that the presence of some species within parasite communities may allow researchers to determine the sites of origin for newly sampled rats. The results of our study help clarify the roles that colony structure and geographical proximity play in determining the ecology of R. norvegicus as a significant urban reservoir of zoonotic diseases. Our study also highlights the spatial variation present in urban

Variations in levels of care between nursing home patients in a public health care system.

Science.gov (United States)

Døhl, Øystein; Garåsen, Helge; Kalseth, Jorid; Magnussen, Jon

2014-03-05

Within the setting of a public health service we analyse the distribution of resources between individuals in nursing homes funded by global budgets. Three questions are pursued. Firstly, whether there are systematic variations between nursing homes in the level of care given to patients. Secondly, whether such variations can be explained by nursing home characteristics. And thirdly, how individual need-related variables are associated with differences in the level of care given. The study included 1204 residents in 35 nursing homes and extra care sheltered housing facilities. Direct time spent with patients was recorded. In average each patient received 14.8 hours direct care each week. Multilevel regression analysis is used to analyse the relationship between individual characteristics, nursing home characteristics and time spent with patients in nursing homes. The study setting is the city of Trondheim, with a population of approximately 180 000. There are large variations between nursing homes in the total amount of individual care given to patients. As much as 24 percent of the variation of individual care between patients could be explained by variation between nursing homes. Adjusting for structural nursing home characteristics did not substantially reduce the variation between nursing homes. As expected a negative association was found between individual care and case-mix, implying that at nursing home level a more resource demanding case-mix is compensated by lowering the average amount of care. At individual level ADL-disability is the strongest predictor for use of resources in nursing homes. For the average user one point increase in ADL-disability increases the use of resources with 27 percent. In a financial reimbursement model for nursing homes with no adjustment for case-mix, the amount of care patients receive does not solely depend on the patients' own needs, but also on the needs of all the other residents.

Development of the structural materials information center

International Nuclear Information System (INIS)

Oland, C.B.; Naus, D.J.

1990-01-01

The U.S. Nuclear Regulatory Commission has initiated a Structural Aging Program at the Oak Ridge National Laboratory to identify potential structural safety issues related to continued service of nuclear power plants and to establish criteria for evaluating and resolving these issues. One of the tasks in this program focuses on the establishment of a Structural Materials Information Center where data and information on the time variation of concrete and other structural material properties under the influence of pertinent environmental stressors and aging factors are being collected and assembled into a database. This database will be used to assist in the prediction of potential long-term deterioration of critical structural components in nuclear power plants and to establish limits on hostile environmental exposure for these structures and materials. Two complementary database formats have been developed. The Structural Materials Handbook is an expandable, hard copy handbook that contains complete sets of data and information for selected portland cement concrete, metallic reinforcement, prestressing tendon, and structural steel materials. The Structural Materials Electronic Database is accessible by an IBM-compatible personal computer and provides an efficient means for searching the various database files to locate materials with similar properties. The database formats have been developed to accommodate data and information on the time-variation of concrete and other structural material properties. To date, the database includes information on concrete, reinforcement, prestressing, and structural steel materials

Introduction to natural disturbances and historic range of variation: type, frequency, severity, and post-disturbance structure in central hardwood forests

Science.gov (United States)

Katie Greenberg; Beverly S. Collins; Henry McNab; Douglas K. Miller; Gary R. Wein

2015-01-01

EXCERPT FROM: Natural Disturbances and Historic Range Variation 2015. Throughout the history of upland hardwood forests of the Central Hardwood Region, natural disturbances have been integral to shaping forest structure and composition, and essential in maintaining diverse biotic...

Ab initio localized basis set study of structural parameters and elastic properties of HfO2 polymorphs

International Nuclear Information System (INIS)

Caravaca, M A; Casali, R A

2005-01-01

The SIESTA approach based on pseudopotentials and a localized basis set is used to calculate the electronic, elastic and equilibrium properties of P 2 1 /c, Pbca, Pnma, Fm3m, P4 2 nmc and Pa3 phases of HfO 2 . Using separable Troullier-Martins norm-conserving pseudopotentials which include partial core corrections for Hf, we tested important physical properties as a function of the basis set size, grid size and cut-off ratio of the pseudo-atomic orbitals (PAOs). We found that calculations in this oxide with the LDA approach and using a minimal basis set (simple zeta, SZ) improve calculated phase transition pressures with respect to the double-zeta basis set and LDA (DZ-LDA), and show similar accuracy to that determined with the PPPW and GGA approach. Still, the equilibrium volumes and structural properties calculated with SZ-LDA compare better with experiments than the GGA approach. The bandgaps and elastic and structural properties calculated with DZ-LDA are accurate in agreement with previous state of the art ab initio calculations and experimental evidence and cannot be improved with a polarized basis set. These calculated properties show low sensitivity to the PAO localization parameter range between 40 and 100 meV. However, this is not true for the relative energy, which improves upon decrease of the mentioned parameter. We found a non-linear behaviour in the lattice parameters with pressure in the P 2 1 /c phase, showing a discontinuity of the derivative of the a lattice parameter with respect to external pressure, as found in experiments. The common enthalpy values calculated with the minimal basis set give pressure transitions of 3.3 and 10.8?GPa for P2 1 /c → Pbca and Pbca → Pnma, respectively, in accordance with different high pressure experimental values

FLORISTIC-STRUCTURAL VARIATION OF NATURAL REGENERATION ALONG DIFFERENT TOPOGRAPHIC POSITIONS OF AN ECOTONAL FOREST IN SANTA CATARINA, BRAZIL

Directory of Open Access Journals (Sweden)

Chayane Cristina de Souza

2017-08-01

Full Text Available ABSTRACT Studies on the natural regeneration of tree species communities are important for providing information on forest development capacity. This research aimed to evaluate the floristic-structural variations of the tree regenerative component along a topographic gradient in an ecotonal area between a Mixed Ombrophilous Forest and a Deciduous Seasonal Forest of Santa Catarina, Brazil. 30 sampling units of which all regenerating tree species individuals have been identified were allocated in the forest fragment. The sampling units were then distributed along a topographic gradient into lower, intermediate and upper sectors. Abundance, richness, Shannon's diversity index (H' and Pielou's evenness index (J have been determined for both the whole community as for each sector. The community floristic-structural organization was verified by the means of the non-metric multidimensional scaling (NMDS, the indicator species analysis and the permutational multivariate analysis of variance (PERMANOVA. Abundance differences among sectors were analyzed through the Kruskal-Wallis test with post hoc multiple nonparametric test while richness differences were verified through rarefaction. Regenerating individuals density in the upper sector [129 (21.300 ind.ha-1] was lower than both in the lower [401 (63.800 ind.ha-1] and intermediary [241 (36.300 ind.ha-1] sectors. There was variation in the floristic-structural composition (p < 0.001 among topographic positions; the lower sector was the most distinct one and showed the highest number of indicator species.

Abolition of set-aside schemes, associated impacts on habitat structure and modelling of potential effects of cross-farm regulation

DEFF Research Database (Denmark)

Levin, G.; Jepsen, Martin Rudbeck

2010-01-01

proportion of set-aside land was re-cultivated. With Denmark as case we apply an indicator to measure the effect of set-aside land on spatial structure of semi-natural habitats in term of habitat size and connectivity. Furthermore, we model effects of a hypothetical spatial regulation, where set-aside land...... reduces impacts. Effects increase with increasing size of farm agglomerations. However, marginal benefits become negligible at agglomeration sizes over 36 km(2). (C) 2010 Elsevier B.V. All rights reserved...

Structural monitoring of a highway bridge using passive noise recordings from street traffic.

Science.gov (United States)

Salvermoser, Johannes; Hadziioannou, Céline; Stähler, Simon C

2015-12-01

Structural damage on bridges presents a hazard to public safety and can lead to fatalities. This article contributes to the development of an alternative monitoring system for civil structures, based on passive measurements of seismic elastic waves. Cross-correlations of traffic noise recorded at geophone receiver pairs were found to be sufficiently stable for comparison and sensitive to velocity changes in the medium. As such velocity variations could be caused by damage, their detection would be valuable in structural health monitoring systems. A method, originally introduced for seismological applications and named Passive Image Interferometry, was used to quantify small velocity fluctuations in the medium and thereby observe structural changes. Evaluation of more than 2 months of continuous geophone recordings at a reinforced concrete bridge yielded velocity variations Δv/v in the range of -1.5% to +2.1%. The observed fluctuations correlate with associated temperature time series with a striking resemblance which is remarkable for two completely independent data sets. Using a linear regression approach, a relationship between temperature and velocity variations of on average 0.064% °C(-1) can be identified. This value corresponds well to other studies on concrete structures.

Seasonal and solar cycle variations in the ionospheric convection reversal boundary location inferred from monthly SuperDARN data sets

Directory of Open Access Journals (Sweden)

A. V. Koustov

2016-02-01

Full Text Available Multi-year (1995–2013 velocity data collected by the Super Dual Auroral Network (SuperDARN HF radars are considered to investigate seasonal and solar cycle variations of the convection reversal boundary (CRB location for interplanetary magnetic field (IMF Bz < 0. By considering monthly data sets we show that the CRB is at higher latitudes in summer between 1995 and 2007. The poleward shifts are on the order of 2–5°. After 2007, the seasonal effect weakens, and the highest latitudes for the CRB start to occur during the winter time. We show that the CRB latitudes decrease with an increase of the IMF transverse component at a rate of (1–2°/2 nT. Because of this effect, on average, the CRB latitudes are lower during high solar activity periods with stronger IMFs. We also confirm the effect of the CRB dawn-dusk shifts related to the IMF changes in the IMF By sign.

Continuous monitoring of setting and hardening of mortar using FBG sensors

Science.gov (United States)

Lima, H.; Ribeiro, R.; Nogueira, R.; Silva, L.; Abe, I.; Pinto, J. L.

2007-05-01

The use of fibre Bragg grating sensors to study mortars' dimensional variations during the setting process is reported. When determining a mortar's potential to fissure, it's important to know its total retraction. This means it is necessary to know not only the mortar's retraction after hardened, but also to know how much it retracts during the plastic phase. This work presents a technique which allows to measure dimensional variations, either expansion or retraction, during the whole setting process. Temperature and strain evolution during both plastic and hardened phase of the mortar were obtained, allowing the determination of dimensional variations and setting times. Due to its high-speed, ease of implementation and low operation costs, this technique will allow to get a deeper knowledge of the effects of several additives on the mortar's behaviour, allowing to improve its mechanical properties through the determination of the proper chemical composition.

Structural Integrity Analysis considered Load Combination for the Conceptual Design of Korean HCCR TBM-set

Energy Technology Data Exchange (ETDEWEB)

Lee, Dong Won; Jin, Hyung Gon; Lee, Eo Hwak; Yoon, Jae Sung; Kim, Suk Kwon [KAERI, Daejeon (Korea, Republic of); Shin, Kyu In [Gentec Tech, Daejeon (Korea, Republic of); Cho, Seungyon [National Fusion Research Institute, Daejeon (Korea, Republic of)

2015-05-15

HCCR TBM (Test Blanket Module) set is consist of 4-TBM sub module, one blanket manifold (BM), a shield, and 4-key, which has a function of a connection between BM and the shield. And it shall be installed in the equatorial port No.18 of ITER inside the vacuum vessel directly facing the plasma and shall be cooled by a high-temperature helium coolant. In addition, the HCCR TBM-set safety classification follows the ITER (international thermonuclear reactor) safety importance class (SIC) criteria, and satisfies a design requirement according to RCC-MRx. In this study, some of load combination (LC) analysis for the structure integrity of TBM set were carried out based on the reference. And the LC results showed that they satisfied the design requirement. The material of TBM-set was used from the reference, and RCC-MRx for the stress analysis. In this study, the load combination results were met a design requirement. But some load combination case gave a higher maximum stress value than a design requirement and in these case the stress breakdown analysis according to RCC-MRx was performed, and the result were satisfied the design requirement.

Structured assessment of microsurgery skills in the clinical setting.

Science.gov (United States)

Chan, WoanYi; Niranjan, Niri; Ramakrishnan, Venkat

2010-08-01

Microsurgery is an essential component in plastic surgery training. Competence has become an important issue in current surgical practice and training. The complexity of microsurgery requires detailed assessment and feedback on skills components. This article proposes a method of Structured Assessment of Microsurgery Skills (SAMS) in a clinical setting. Three types of assessment (i.e., modified Global Rating Score, errors list and summative rating) were incorporated to develop the SAMS method. Clinical anastomoses were recorded on videos using a digital microscope system and were rated by three consultants independently and in a blinded fashion. Fifteen clinical cases of microvascular anastomoses performed by trainees and a consultant microsurgeon were assessed using SAMS. The consultant had consistently the highest scores. Construct validity was also demonstrated by improvement of SAMS scores of microsurgery trainees. The overall inter-rater reliability was strong (alpha=0.78). The SAMS method provides both formative and summative assessment of microsurgery skills. It is demonstrated to be a valid, reliable and feasible assessment tool of operating room performance to provide systematic and comprehensive feedback as part of the learning cycle. Copyright 2009 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.

Large-scale variation in lithospheric structure along and across the Kenya rift

Science.gov (United States)

Prodehl, C.; Mechie, J.; Kaminski, W.; Fuchs, K.; Grosse, C.; Hoffmann, H.; Stangl, R.; Stellrecht, R.; Khan, M.A.; Maguire, Peter K.H.; Kirk, W.; Keller, Gordon R.; Githui, A.; Baker, M.; Mooney, W.; Criley, E.; Luetgert, J.; Jacob, B.; Thybo, H.; Demartin, M.; Scarascia, S.; Hirn, A.; Bowman, J.R.; Nyambok, I.; Gaciri, S.; Patel, J.; Dindi, E.; Griffiths, D.H.; King, R.F.; Mussett, A.E.; Braile, L.W.; Thompson, G.; Olsen, K.; Harder, S.; Vees, R.; Gajewski, D.; Schulte, A.; Obel, J.; Mwango, F.; Mukinya, J.; Riaroh, D.

1991-01-01

The Kenya rift is one of the classic examples of a continental rift zone: models for its evolution range from extension of the lithosphere by pure shear1, through extension by simple shear2, to diapiric upwelling of an asthenolith3. Following a pilot study in 19854, the present work involved the shooting of three seismic refraction and wide-angle reflection profiles along the axis, across the margins, and on the northeastern flank of the rift (Fig. 1). These lines were intended to reconcile the different crustal thickness estimates for the northern and southern parts of the rift4-6 and to reveal the structure across the rift, including that beneath the flanks. The data, presented here, reveal significant lateral variations in structure both along and across the rift. The crust thins along the rift axis from 35 km in the south to 20 km in the north; there are abrupt changes in Mono depth and uppermost-mantle seismic velocity across the rift margins, and crustal thickening across the boundary between the Archaean craton and PanAfrican orogenic belt immediately west of the rift. These results suggest that thickened crust may have controlled the rift's location, that there is a decrease in extension from north to south, and that the upper mantle immediately beneath the rift may contain reservoirs of magma generated at greater depth.

Discrete variational methods and their application to electronic structures

International Nuclear Information System (INIS)

Ellis, D.E.

1987-01-01

Some general concepts concerning Discrete Variational methods are developed and applied to problems of determination of eletronic spectra, charge densities and bonding of free molecules, surface-chemisorbed species and bulk solids. (M.W.O.) [pt

Temporal correlation in the Goldberg variations

OpenAIRE

Chestopal, Victor

2010-01-01

An interpreter of the Goldberg Variations is almost completely deprived of such utterly important guidance as the composer's tempo markings, which are as rare in the Goldberg Variations as they are in the other works of Bach. The final goal of my study is to suggest a logical foundation, upon which an interpreter of the Goldberg Variations can make his/her choice of tempi. Upon the analysis of opus's structure, which reveals an impressive panorama of symmetries, I suggest a multilevel system ...

Spatial structure of morphological and neutral genetic variation in Brook Trout

Science.gov (United States)

Kazyak, David C.; Hilderbrand, Robert H.; Keller, Stephen R.; Colaw, Mark C.; Holloway, Amanda E.; Morgan, Raymond P.; King, Timothy L.

2015-01-01

Brook Trout Salvelinus fontinalis exhibit exceptional levels of life history variation, remarkable genetic variability, and fine-scale population structure. In many cases, neighboring populations may be highly differentiated from one another to an extent that is comparable with species-level distinctions in other taxa. Although genetic samples have been collected from hundreds of populations and tens of thousands of individuals, little is known about whether differentiation at neutral markers reflects phenotypic differences among Brook Trout populations. We compared differentiation in morphology and neutral molecular markers among populations from four geographically proximate locations (all within 24 km) to examine how genetic diversity covaries with morphology. We found significant differences among and/or within streams for all three morphological axes examined and identified the source stream of many individuals based on morphology (52.3% classification efficiency). Although molecular and morphological differentiation among streams ranged considerably (mean pairwise FST: 0.023–0.264; pairwise PST: 0.000–0.339), the two measures were not significantly correlated. While in some cases morphological characters appear to have diverged to a greater extent than expected by neutral genetic drift, many traits were conserved to a greater extent than were neutral genetic markers. Thus, while Brook Trout exhibit fine-scale spatial patterns in both morphology and neutral genetic diversity, these types of biological variabilities are being structured by different ecological and evolutionary processes. The relative influences of genetic drift versus selection and phenotypic plasticity in shaping morphology appear to vary among populations occupying nearby streams.

Structural basis for inhibition of the histone chaperone activity of SET/TAF-Iβ by cytochrome c.

Science.gov (United States)

González-Arzola, Katiuska; Díaz-Moreno, Irene; Cano-González, Ana; Díaz-Quintana, Antonio; Velázquez-Campoy, Adrián; Moreno-Beltrán, Blas; López-Rivas, Abelardo; De la Rosa, Miguel A

2015-08-11

Chromatin is pivotal for regulation of the DNA damage process insofar as it influences access to DNA and serves as a DNA repair docking site. Recent works identify histone chaperones as key regulators of damaged chromatin's transcriptional activity. However, understanding how chaperones are modulated during DNA damage response is still challenging. This study reveals that the histone chaperone SET/TAF-Iβ interacts with cytochrome c following DNA damage. Specifically, cytochrome c is shown to be translocated into cell nuclei upon induction of DNA damage, but not upon stimulation of the death receptor or stress-induced pathways. Cytochrome c was found to competitively hinder binding of SET/TAF-Iβ to core histones, thereby locking its histone-binding domains and inhibiting its nucleosome assembly activity. In addition, we have used NMR spectroscopy, calorimetry, mutagenesis, and molecular docking to provide an insight into the structural features of the formation of the complex between cytochrome c and SET/TAF-Iβ. Overall, these findings establish a framework for understanding the molecular basis of cytochrome c-mediated blocking of SET/TAF-Iβ, which subsequently may facilitate the development of new drugs to silence the oncogenic effect of SET/TAF-Iβ's histone chaperone activity.

Assessment of variations in taxonomic diversity, forest structure, and aboveground biomass using remote sensing along an altitudinal gradient in tropical montane forest of Costa Rica

Science.gov (United States)

Robinson, C. M.; Saatchi, S. S.; Clark, D.; Fricker, G. A.; Wolf, J.; Gillespie, T. W.; Rovzar, C. M.; Andelman, S.

2012-12-01

This research sought to understand how alpha and beta diversity of plants vary and relate to the three-dimensional vegetation structure and aboveground biomass along environmental gradients in the tropical montane forests of Braulio Carrillo National Park in Costa Rica. There is growing evidence that ecosystem structure plays an important role in defining patterns of species diversity and along with abiotic factors (climate and edaphic) control the phenotypic and functional variations across landscapes. It is well documented that strong subdivisions at local and regional scales are found mainly on geologic or climate gradients. These general determinants of biodiversity are best demonstrated in regions with natural gradients such as tropical montane forests. Altitudinal gradients provide a landscape scale changes through variations in topography, climate, and edaphic conditions on which we tested several theoretical and biological hypotheses regarding drivers of biodiversity. The study was performed by using forest inventory and botanical data from nine 1-ha plots ranging from 100 m to 2800 m above sea level and remote sensing data from airborne lidar and radar sensors to quantify variations in forest structure. In this study we report on the effectiveness of relating patterns of tree taxonomic alpha diversity to three-dimensional structure of a tropical montane forest using lidar and radar observations of forest structure and biomass. We assessed alpha and beta diversity at the species, genus, and family levels utilizing datasets provided by the Terrestrial Ecology Assessment and Monitoring (TEAM) Network. Through the comparison to active remote sensing imagery, our results show that there is a strong relationship between forest 3D-structure, and alpha and beta diversity controlled by variations in abiotic factors along the altitudinal gradient. Using spatial analysis with the aid of remote sensing data, we find distinct patterns along the environmental gradients

Interrelated chemical-microstructural-nanomechanical variations in the structural units of the cuttlebone of Sepia officinalis

Science.gov (United States)

North, L.; Labonte, D.; Oyen, M. L.; Coleman, M. P.; Caliskan, H. B.; Johnston, R. E.

2017-11-01

"Cuttlebone," the internalized shell found in all members of the cephalopod family Sepiidae, is a sophisticated buoyancy device combining high porosity with considerable strength. Using a complementary suite of characterization tools, we identified significant structural, chemical, and mechanical variations across the different structural units of the cuttlebone: the dorsal shield consists of two stiff and hard layers with prismatic mineral organization which encapsulate a more ductile and compliant layer with a lamellar structure, enriched with organic matter. A similar organization is found in the chambers, which are separated by septa, and supported by meandering plates ("pillars"). Like the dorsal shield, septa contain two layers with lamellar and prismatic organization, respectively, which differ significantly in their mechanical properties: layers with prismatic organization are a factor of three stiffer and up to a factor of ten harder than those with lamellar organization. The combination of stiff and hard, and compliant and ductile components may serve to reduce the risk of catastrophic failure, and reflect the role of organic matter for the growth process of the cuttlebone. Mechanically "weaker" units may function as sacrificial structures, ensuring a stepwise failure of the individual chambers in cases of overloading, allowing the animals to retain near-neutral buoyancy even with partially damaged cuttlebones. Our findings have implications for our understanding of the structure-property-function relationship of cuttlebone, and may help to identify novel bioinspired design strategies for light-weight yet high-strength foams.

Impact of the variation in dynamic vehicle load on flexible pavement responses

Science.gov (United States)

Ahsanuzzaman, Md

The purpose of this research was to evaluate the dynamic variation in asphalt pavement critical responses due to dynamic tire load variations. An attempt was also made to develop generalized regression equations to predict the dynamic response variation in flexible pavement under various dynamic load conditions. The study used an extensive database of computed pavement response histories for five different types of sites (smooth, rough, medium rough, very rough and severely rough), two different asphalt pavement structures (thin and thick) at two temperatures (70 °F and 104 °F), subjected to a tandem axle dual tire at three speeds 25, 37 and 50 mph (40, 60 and 80 km/h). All pavement responses were determined using the 3D-Move Analysis program (Version 1.2) developed by University of Nevada, Reno. A new term called Dynamic Response Coefficient (DRC) was introduced in this study to address the variation in critical pavement responses due to dynamic loads as traditionally measured by the Dynamic Load Coefficient (DLC). While DLC represents the additional varying component of the tire load, DRC represents the additional varying component of the response value (standard deviation divided by mean response). In this study, DRC was compared with DLC for five different sites based on the roughness condition of the sites. Previous studies showed that DLC varies with vehicle speed and suspension types, and assumes a constant value for the whole pavement structure (lateral and vertical directions). On the other hand, in this study, DRC was found to be significantly varied with the asphalt pavement and function of pavement structure, road roughness conditions, temperatures, vehicle speeds, suspension types, and locations of the point of interest in the pavement. A major contribution of the study is that the variation of pavement responses due to dynamic load in a flexible pavement system can be predicted with generalized regression equations. Fitting parameters (R2) in the

Among-Population Variation in Microbial Community Structure in the Floral Nectar of the Bee-Pollinated Forest Herb Pulmonaria officinalis L

Science.gov (United States)

Jacquemyn, Hans; Lenaerts, Marijke; Brys, Rein; Willems, Kris; Honnay, Olivier; Lievens, Bart

2013-01-01

Background Microbial communities in floral nectar have been shown to be characterized by low levels of species diversity, yet little is known about among-plant population variation in microbial community composition. Methodology/Principal Findings We investigated the microbial community structure (yeasts and bacteria) in floral nectar of ten fragmented populations of the bee-pollinated forest herb Pulmonaria officinalis. We also explored possible relationships between plant population size and microbial diversity in nectar, and related microbial community composition to the distance separating plant populations. Culturable bacteria and yeasts occurring in the floral nectar of a total of 100 plant individuals were isolated and identified by partially sequencing the 16S rRNA gene and D1/D2 domains of the 26S rRNA gene, respectively. A total of 9 and 11 yeast and 28 and 39 bacterial OTUs was found, taking into account a 3% (OTU0.03) and 1% sequence dissimilarity cut-off (OTU0.01). OTU richness at the plant population level (i.e. the number of OTUs per population) was low for yeasts (mean: 1.7, range: 0–4 OTUs0.01/0.03 per population), whereas on average 6.9 (range: 2–13) OTUs0.03 and 7.9 (range 2–16) OTUs0.01 per population were found for bacteria. Both for yeasts and bacteria, OTU richness was not significantly related to plant population size. Similarity in community composition among populations was low (average Jaccard index: 0.14), and did not decline with increasing distance between populations. Conclusions/Significance We found low similarity in microbial community structure among populations, suggesting that the assembly of nectar microbiota is to a large extent context-dependent. Although the precise factors that affect variation in microbial community structure in floral nectar require further study, our results indicate that both local and regional processes may contribute to among-population variation in microbial community structure in nectar. PMID

Mean field theories and dual variation mathematical structures of the mesoscopic model

CERN Document Server

Suzuki, Takashi

2015-01-01

Mean field approximation has been adopted to describe macroscopic phenomena from microscopic overviews. It is still in progress; fluid mechanics, gauge theory, plasma physics, quantum chemistry, mathematical oncology, non-equilibirum thermodynamics.  spite of such a wide range of scientific areas that are concerned with the mean field theory, a unified study of its mathematical structure has not been discussed explicitly in the open literature.  The benefit of this point of view on nonlinear problems should have significant impact on future research, as will be seen from the underlying features of self-assembly or bottom-up self-organization which is to be illustrated in a unified way. The aim of this book is to formulate the variational and hierarchical aspects of the equations that arise in the mean field theory from macroscopic profiles to microscopic principles, from dynamics to equilibrium, and from biological models to models that arise from chemistry and physics.

Spatial variation of dung beetle assemblages associated with forest structure in remnants of southern Brazilian Atlantic Forest

Directory of Open Access Journals (Sweden)

Pedro Giovâni da Silva

2016-01-01

Full Text Available The Brazilian Atlantic Forest is one of the world's biodiversity hotspots, and is currently highly fragmented and disturbed due to human activities. Variation in environmental conditions in the Atlantic Forest can influence the distribution of species, which may show associations with some environmental features. Dung beetles (Coleoptera: Scarabaeinae are insects that act in nutrient cycling via organic matter decomposition and have been used for monitoring environmental changes. The aim of this study is to identify associations between the spatial distribution of dung beetle species and Atlantic Forest structure. The spatial distribution of some dung beetle species was associated with structural forest features. The number of species among the sampling sites ranged widely, and few species were found in all remnant areas. Principal coordinates analysis indicated that species composition, abundance and biomass showed a spatially structured distribution, and these results were corroborated by permutational multivariate analysis of variance. The indicator value index and redundancy analysis showed an association of several dung beetle species with some explanatory environmental variables related to Atlantic Forest structure. This work demonstrated the existence of a spatially structured distribution of dung beetles, with significant associations between several species and forest structure in Atlantic Forest remnants from Southern Brazil. Keywords: Beta diversity, Species composition, Species diversity, Spatial distribution, Tropical forest

Geography, Ethnicity or Subsistence-Specific Variations in Human Microbiome Composition and Diversity

Directory of Open Access Journals (Sweden)

Vinod K. Gupta

2017-06-01

Full Text Available One of the fundamental issues in the microbiome research is characterization of the healthy human microbiota. Recent studies have elucidated substantial divergences in the microbiome structure between healthy individuals from different race and ethnicity. This review provides a comprehensive account of such geography, ethnicity or life-style-specific variations in healthy microbiome at five major body habitats—Gut, Oral-cavity, Respiratory Tract, Skin, and Urogenital Tract (UGT. The review focuses on the general trend in the human microbiome evolution—a gradual transition in the gross compositional structure along with a continual decrease in diversity of the microbiome, especially of the gut microbiome, as the human populations passed through three stages of subsistence like foraging, rural farming and industrialized urban western life. In general, gut microbiome of the hunter-gatherer populations is highly abundant with Prevotella, Proteobacteria, Spirochaetes, Clostridiales, Ruminobacter etc., while those of the urban communities are often enriched in Bacteroides, Bifidobacterium, and Firmicutes. The oral and skin microbiome are the next most diverse among different populations, while respiratory tract and UGT microbiome show lesser variations. Higher microbiome diversity is observed for oral-cavity in hunter-gatherer group with higher prevalence of Haemophilus than agricultural group. In case of skin microbiome, rural and urban Chinese populations show variation in abundance of Trabulsiella and Propionibacterium. On the basis of published data, we have characterized the core microbiota—the set of genera commonly found in all populations, irrespective of their geographic locations, ethnicity or mode of subsistence. We have also identified the major factors responsible for geography-based alterations in microbiota; though it is not yet clear which factor plays a dominant role in shaping the microbiome—nature or nurture, host genetics

Morphodynamics structures induced by variations of the channel width

Science.gov (United States)

Duro, Gonzalo; Crosato, Alessandra; Tassi, Pablo

2014-05-01

In alluvial channels, forcing effects, such as a longitudinally varying width, can induce the formation of steady bars (Olesen, 1984). The type of bars that form, such as alternate, central or multiple, will mainly depend on the local flow width-to-depth ratio and on upstream conditions (Struiksma et al., 1985). The effects on bar formation of varying the channel width received attention only recently and investigations, based on flume experiments and mathematical modelling, are mostly restricted to small longitudinal sinusoidal variations of the channel width (e.g. Repetto et al., 2002; Wu and Yeh, 2005, Zolezzi et al., 2012; Frascati and Lanzoni, 2013). In this work, we analyze the variations in equilibrium bed topography in a longitudinal width-varying channel with characteristic scales of the Waal River (The Netherlands) using two different 2D depth-averaged morphodynamic models, one based on the Delft3D code and one on Telemac-Mascaret system. In particular, we explore the effects of changing the wavelength of sinusoidal width variations in a straight channel, focusing on the effects of the spatial lag between bar formation and forcing that is observed in numerical models and laboratory experiments (e.g. Crosato et al, 2011). We extend the investigations to finite width variations in which longitudinal changes of the width-to-depth ratio are such that they may affect the type of bars that become unstable (alternate, central or multiple bars). Numerical results are qualitatively validated with field observations and the resulting morphodynamic pattern is compared with the physics-based predictor of river bar modes by Crosato and Mosselman (2009). The numerical models are finally used to analyse the experimental conditions of Wu and Yeh (2005). The study should be seen as merely exploratory. The aim is to investigate possible approaches for future research aiming at assessing the effects of artificial river widening and narrowing to control bar formation in

Structure Optimal Design of Electromagnetic Levitation Load Reduction Device for Hydroturbine Generator Set

Directory of Open Access Journals (Sweden)

Qingyan Wang

2015-01-01

Full Text Available Thrust bearing is one part with the highest failure rate in hydroturbine generator set, which is primarily due to heavy axial load. Such heavy load often makes oil film destruction, bearing friction, and even burning. It is necessary to study the load and the reduction method. The dynamic thrust is an important factor to influence the axial load and reduction design of electromagnetic device. Therefore, in the paper, combined with the structure features of vertical turbine, the hydraulic thrust is analyzed accurately. Then, take the turbine model HL-220-LT-550, for instance; the electromagnetic levitation load reduction device is designed, and its mathematical model is built, whose purpose is to minimize excitation loss and total quality under the constraints of installation space, connection layout, and heat dissipation. Particle swarm optimization (PSO is employed to search for the optimum solution; finally, the result is verified by finite element method (FEM, which demonstrates that the optimized structure is more effective.

On a variational principle for shape optimization and elliptic free boundary problems

Directory of Open Access Journals (Sweden)

Raúl B. González De Paz

2009-02-01

Full Text Available A variational principle for several free boundary value problems using a relaxation approach is presented. The relaxed Energy functional is concave and it is defined on a convex set, so that the minimizing points are characteristic functions of sets. As a consequence of the first order optimality conditions, it is shown that the corresponding sets are domains bounded by free boundaries, so that the equivalence of the solution of the relaxed problem with the solution of several free boundary value problem is proved. Keywords: Calculus of variations, optimization, free boundary problems.

Difference Discrete Variational Principle,EULER-Lagrange Cohomology and Symplectic, Multisymplectic Structures

OpenAIRE

Guo, H. Y.; Li, Y. Q.; Wu, K.; Wang, S. K.

2001-01-01

We study the difference discrete variational principle in the framework of multi-parameter differential approach by regarding the forward difference as an entire geometric object in view of noncomutative differential geometry. By virtue of this variational principle, we get the difference discrete Euler-Lagrange equations and canonical ones for the difference discrete versions of the classical mechanics and classical field theory. We also explore the difference discrete versions for the Euler...

Electrical structure and its implication across the lower- and upper-crustal settings of South India

Science.gov (United States)

Raval, U.

1988-01-01

Measurements of a large scale MMA experiment covering both the granulite and greenstone terrains of Archeans in the southern part of India is re-visited and re-analyzed. The induced field variations contain the signatures of crustal and subcrustal electrical conductivities, although substantially distorted by the sea-land interfaces and cenozoic sediments. However, through a selection of some reconnaissance profiles and temporal variations, an attempt is made to deduce whether: (1) significant differences exist between the electrical structures of the high and low grade complexes (i.e., if the electrical conductivity of the lower crust is due to minerological composition or is intrinsic to the positioning at depths greater than 15 km); (2) the probable seaward extension of the continental crust and its transition to oceanic type may also contribute (through intracrustal DC-like telluric sheets) to the induction field in addition to or rather than the sharply localized zones; (3) the observed parameters are indicative of a formal anisotropy and/or undulations in the deep crust; and (4) the postulate of relatively hotter Indian shield is reflected particularly with regard to differential metamorphism. In the last case, the crust-mantle coupling in this region - unlike other similar areas - seems to be markedly affected by the evolution of Ne-plate velocity field.

Characterizing Interfraction Variations and Their Dosimetric Effects in Prostate Cancer Radiotherapy

International Nuclear Information System (INIS)

Peng Cheng; Ahunbay, Ergun; Chen Guangpei; Anderson, Savannah; Lawton, Colleen; Li, X. Allen

2011-01-01

Purpose: To quantitatively characterize the interfraction variations and their dosimetric effects in radiotherapy for prostate cancer. Methods and Materials: A total of 486 daily computed tomography (CT) sets acquired for 20 prostate cancer patients treated with daily CT-guided repositioning using a linear accelerator and CT-on-rail combination were analyzed. The prostate, rectum, and bladder, delineated on each daily CT data set, were compared with those from the planning CT scan. Several quantities, including Dice's coefficient and the maximal overlapping rate, were used to characterize the interfraction variations. The delivered dose was reconstructed by applying the original plan to the daily CT scan with consideration of proper repositioning. Results: The mean prostate Dice's coefficient and maximal overlapping rate after bony registration was 69.7% ± 13.8% (standard deviation) and 85.6% ± 7.8% (standard deviation), respectively. The daily delivered dose distributions were generally inferior to the planned dose distribution for target coverage and/or normal structure sparing. For example, for approximately 5% of the treatment fractions, the prostate volume receiving 100% of the prescription dose decreased dramatically (15-20%) compared with its planned value. The magnitudes of the interfraction variations and their dosimetric effects indicated that, statistically, current standard repositioning using prostate alignment might be adequate for two-thirds of the fractions, but for the rest of the fractions, better on-line correction strategies, such as on-line replanning, are needed. Conclusion: Different adaptive correction schemes for prostatic interfraction changes can be used according to the anatomic changes, as quantified by the organ displacement and deformation parameters. On-line replanning is needed for approximately one-third of the treatment fractions.

Fine Physical Bin Mapping of the Powdery Mildew Resistance Gene Pm21 Based on Chromosomal Structural Variations in Wheat

Directory of Open Access Journals (Sweden)

Shanying Zhu

2018-02-01

Full Text Available Pm21, derived from wheat wild relative Dasypyrum villosum, is one of the most effective powdery mildew resistance genes and has been widely applied in wheat breeding in China. Mapping and cloning Pm21 are of importance for understanding its resistance mechanism. In the present study, physical mapping was performed using different genetic stocks involving in structural variations of chromosome 6VS carrying Pm21. The data showed that 6VS could be divided into eight distinguishable chromosomal bins, and Pm21 was mapped to the bin FLb4–b5/b6 closely flanked by the markers 6VS-08.6 and 6VS-10.2. Comparative genomic mapping indicated that the orthologous regions of FLb4–b5/b6 carrying Pm21 were narrowed to a 117.7 kb genomic region harboring 19 genes in Brachypodium and a 37.7 kb region harboring 5 genes in rice, respectively. The result was consistent with that given by recent genetic mapping in diploid D. villosum. In conclusion, this study demonstrated that physical mapping based on chromosomal structural variations is an efficient method for locating alien genes in wheat background.

Transducer placement for robustness to variations in boundary conditions for active structural acoustic control

Science.gov (United States)

Sprofera, Joseph D.; Clark, Robert L.; Cabell, Randolph H.; Gibbs, Gary P.

2005-05-01

Turbulent boundary layer (TBL) noise is considered a primary contribution to the interior noise present in commercial airliners. There are numerous investigations of interior noise control devoted to aircraft panels; however, practical realization is a potential challenge since physical boundary conditions are uncertain at best. In most prior studies, pinned or clamped boundary conditions were assumed; however, realistic panels likely display a range of boundary conditions between these two limits. Uncertainty in boundary conditions is a challenge for control system designers, both in terms of the compensator implemented and the location of transducers required to achieve the desired control. The impact of model uncertainties, specifically uncertain boundaries, on the selection of transducer locations for structural acoustic control is considered herein. The final goal of this work is the design of an aircraft panel structure that can reduce TBL noise transmission through the use of a completely adaptive, single-input, single-output control system. The feasibility of this goal is demonstrated through the creation of a detailed analytical solution, followed by the implementation of a test model in a transmission loss apparatus. Successfully realizing a control system robust to variations in boundary conditions can lead to the design and implementation of practical adaptive structures that could be used to control the transmission of sound to the interior of aircraft. Results from this research effort indicate it is possible to optimize the design of actuator and sensor location and aperture, minimizing the impact of boundary conditions on the desired structural acoustic control.

Window area and development drive spatial variation in bird-window collisions in an urban landscape.

Science.gov (United States)

Hager, Stephen B; Cosentino, Bradley J; McKay, Kelly J; Monson, Cathleen; Zuurdeeg, Walt; Blevins, Brian

2013-01-01

Collisions with windows are an important human-related threat to birds in urban landscapes. However, the proximate drivers of collisions are not well understood, and no study has examined spatial variation in mortality in an urban setting. We hypothesized that the number of fatalities at buildings varies with window area and habitat features that influence avian community structure. In 2010 we documented bird-window collisions (BWCs) and characterized avian community structure at 20 buildings in an urban landscape in northwestern Illinois, USA. For each building and season, we conducted 21 daily surveys for carcasses and nine point count surveys to estimate relative abundance, richness, and diversity. Our sampling design was informed by experimentally estimated carcass persistence times and detection probabilities. We used linear and generalized linear mixed models to evaluate how habitat features influenced community structure and how mortality was affected by window area and factors that correlated with community structure. The most-supported model was consistent for all community indices and included effects of season, development, and distance to vegetated lots. BWCs were related positively to window area and negatively to development. We documented mortalities for 16/72 (22%) species (34 total carcasses) recorded at buildings, and BWCs were greater for juveniles than adults. Based on the most-supported model of BWCs, the median number of annual predicted fatalities at study buildings was 3 (range = 0-52). These results suggest that patchily distributed environmental resources and levels of window area in buildings create spatial variation in BWCs within and among urban areas. Current mortality estimates place little emphasis on spatial variation, which precludes a fundamental understanding of the issue. To focus conservation efforts, we illustrate how knowledge of the structural and environmental factors that influence bird-window collisions can be used to

Window area and development drive spatial variation in bird-window collisions in an urban landscape.

Directory of Open Access Journals (Sweden)

Stephen B Hager

Full Text Available Collisions with windows are an important human-related threat to birds in urban landscapes. However, the proximate drivers of collisions are not well understood, and no study has examined spatial variation in mortality in an urban setting. We hypothesized that the number of fatalities at buildings varies with window area and habitat features that influence avian community structure. In 2010 we documented bird-window collisions (BWCs and characterized avian community structure at 20 buildings in an urban landscape in northwestern Illinois, USA. For each building and season, we conducted 21 daily surveys for carcasses and nine point count surveys to estimate relative abundance, richness, and diversity. Our sampling design was informed by experimentally estimated carcass persistence times and detection probabilities. We used linear and generalized linear mixed models to evaluate how habitat features influenced community structure and how mortality was affected by window area and factors that correlated with community structure. The most-supported model was consistent for all community indices and included effects of season, development, and distance to vegetated lots. BWCs were related positively to window area and negatively to development. We documented mortalities for 16/72 (22% species (34 total carcasses recorded at buildings, and BWCs were greater for juveniles than adults. Based on the most-supported model of BWCs, the median number of annual predicted fatalities at study buildings was 3 (range = 0-52. These results suggest that patchily distributed environmental resources and levels of window area in buildings create spatial variation in BWCs within and among urban areas. Current mortality estimates place little emphasis on spatial variation, which precludes a fundamental understanding of the issue. To focus conservation efforts, we illustrate how knowledge of the structural and environmental factors that influence bird

Impact testing and analysis for structural code benchmarking

International Nuclear Information System (INIS)

Glass, R.E.

1989-01-01

Sandia National Laboratories, in cooperation with industry and other national laboratories, has been benchmarking computer codes used to predict the structural, thermal, criticality, and shielding behavior of radioactive materials packages. The first step in the benchmarking of the codes was to develop standard problem sets and to compare the results from several codes and users. This step for structural analysis codes has been completed as described in Structural Code Benchmarking for the Analysis of Impact Response of Nuclear Material Shipping Casks, R.E. Glass, Sandia National Laboratories, 1985. The problem set is shown in Fig. 1. This problem set exercised the ability of the codes to predict the response to end (axisymmetric) and side (plane strain) impacts with both elastic and elastic/plastic materials. The results from these problems showed that there is good agreement in predicting elastic response. Significant differences occurred in predicting strains for the elastic/plastic models. An example of the variation in predicting plastic behavior is given, which shows the hoop strain as a function of time at the impacting end of Model B. These differences in predicting plastic strains demonstrated a need for benchmark data for a cask-like problem

Electronic structure simulation of chromium aluminum oxynitride by discrete variational-X{alpha} method and X-ray photoelectron spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Choi, Youngmin; Chang, Hyunju; Lee, Jae Do [Korea Research Inst. of Chemical Technology, Taejon (Korea); Kim, Eunah; No, Kwangsoo [Korea Advanced Inst. of Science and Technology, Taejon (Korea)

2002-09-01

We use a first-principles discrete variational (DV)-X{alpha} method to investigate the electronic structure of chromium aluminum oxynitride. When nitrogen is substituted for oxygen in the Cr-Al-O system, the N2p level appears in the energy range between O2p and Cr3d levels. Consequently, the valence band of chromium aluminum oxynitride becomes broader and the band gap becomes smaller than that of chromium aluminum oxide, which is consistent with the photoelectron spectra for the valence band using X-ray photoelectron spectroscopy (XPS) and ultraviolet photoelectron spectroscopy (UPS). We expect that this valence band structure of chromium aluminum oxynitride will modify the transmittance slope which is a requirement for photomask application. (author)

Structural variation along the southwestern Nankai seismogenic zone related to various earthquake phenomena

Science.gov (United States)

Nakanishi, A.; Shimomura, N.; Kodaira, S.; Obana, K.; Takahashi, T.; Yamamoto, Y.; Sato, T.; Kashiwase, K.; Fujimori, H.; Kaneda, Y.; Mochizuki, K.; Kato, A.; Iidaka, T.; Kurashimo, E.; Shinohara, M.; Takeda, T.; Shiomi, K.

2011-12-01

In the Nankai Trough subduction seismogenic zone, the Nankai and Tonankai earthquakes had often occurred simultaneously, and caused a great event. In order to reduce a great deal of damage to coastal area from both strong ground motion and tsunami generation, it is necessary to understand rupture synchronization and segmentation of the Nankai megathrust earthquake. For a precise estimate of the rupture area of the Nankai megathrust event, it is important to know the geometry of the subducting Philippine Sea plate and deep subduction structure along the Nankai Trough. To obtain the deep subduction structure of the coseismic rupture area of the Nankai earthquake in 1946 off Shikoku area, the large-scale high-resolution wide-angle seismic study was conducted in 2009 and 2010. In this study, 201 and 200 ocean bottom seismographs were deployed off the Shikoku Island and the Kii channel respectively. A tuned airgun system (7800 cu. in.) shot every 200m along 13 profiles. Airgun shots were also recorded along an onshore seismic profile (prepared by ERI, univ. of Tokyo and NIED) prolonged from the offshore profile off the Kii Peninsula. Long-term observation was conducted for ~9 months by 21 OBSs off the Shikoku area and 20 OBSs off the Kii channel.This research is part of 'Research concerning Interaction Between the Tokai, Tonankai and Nankai Earthquakes' funded by Ministry of Education, Culture, Sports, Science and Technology, Japan. Structural images of the overriding plate indicate the old accreted sediments (the Cretaceous-Tertiary accretionary prism) with the velocity greater than 6km/s extend seaward from off the Shikoku to the Hyuga-nada. Moreover, the young accreted sediments become relatively thinner eastward from off the cape Ashizuri to Muroto. These structural variations might be related to the different rupture pattern of the Nankai event. Structural image of the deep low frequency earthquakes and tremors is shown by using the airgun shots recorded at onshore

3D Structure of Iran and Surrounding Areas From The Simultaneous Inversion of Complementary Geophysical Observations

Science.gov (United States)

Ammon, C. J.; Maceira, M.; Cleveland, M.

2010-12-01

We present a three-dimensional seismic-structure model of the Arabian-Eurasian collision zone obtained via simultaneous, joint inversion of surface-wave dispersion measurements, teleseismic P-wave receiver functions, and gravity observations. We use a simple, approximate relationship between density and seismic velocities so that the three data sets may be combined in a single inversion. The sensitivity of the different data sets are well known: surface waves provide information on the smooth variations in elastic properties, receiver functions provide information on abrupt velocity contrasts, and gravity measurements provide information on broad-wavenumber shallow density variations and long-wavenumber components of deeper density structures. The combination of the data provides improved resolution of shallow-structure variations, which in turn help produce the smooth features at depth with less contamination from the strong heterogeneity often observed in the upper crust. We also explore geologically based smoothness constraints to help resolve sharp features in the underlying shallow 3D structure. Our focus is on the region surrounding Iran from east Turkey and Iraq in the west, to Pakistan and Afghanistan in the east. We use Bouguer gravity anomalies derived from the global gravity model extracted from the GRACE satellite mission. Surface-wave dispersion velocities in the period range between 7 and 150 s are taken from previously published tomographic maps for the region. Preliminary results show expected strong variations in the Caspian region as well as the deep sediment regions of the Persian Gulf. Regions constrained with receiver-function information generally show sharper crust-mantle boundary structure than that obtained by inversion of the surface waves alone (with thin layers and smoothing constraints). Final results of the simultaneous inversion will help us to better understand one of the most prominent examples of continental collision. Such models

The four variational principles of mechanics

International Nuclear Information System (INIS)

Gray, C.G.; Karl, G.; Novikov, V.A.

1996-01-01

We argue that there are four basic forms of the variational principles of mechanics: Hamilton close-quote s least action principle (HP), the generalized Maupertuis principle (MP), and their two reciprocal principles, RHP and RMP. This set is invariant under reciprocity and Legendre transformations. One of these forms (HP) is in the literature: only special cases of the other three are known. The generalized MP has a weaker constraint compared to the traditional formulation, only the mean energy bar E is kept fixed between virtual paths. This reformulation of MP alleviates several weaknesses of the old version. The reciprocal Maupertuis principle (RMP) is the classical limit of Schroedinger close-quote s variational principle of quantum mechanics, and this connection emphasizes the importance of the reciprocity transformation for variational principles. Two unconstrained formulations (UHP and UMP) of these four principles are also proposed, with completely specified Lagrange multipliers Percival close-quote s variational principle for invariant tori and variational principles for scattering orbits are derived from the RMP. The RMP is very convenient for approximate variational solutions to problems in mechanics using Ritz type methods Examples are provided. Copyright copyright 1996 Academic Press, Inc

Electronic structure of thin films by the self-consistent numerical-basis-set linear combination of atomic orbitals method: Ni(001)

International Nuclear Information System (INIS)

Wang, C.S.; Freeman, A.J.

1979-01-01

We present the self-consistent numerical-basis-set linear combination of atomic orbitals (LCAO) discrete variational method for treating the electronic structure of thin films. As in the case of bulk solids, this method provides for thin films accurate solutions of the one-particle local density equations with a non-muffin-tin potential. Hamiltonian and overlap matrix elements are evaluated accurately by means of a three-dimensional numerical Diophantine integration scheme. Application of this method is made to the self-consistent solution of one-, three-, and five-layer Ni(001) unsupported films. The LCAO Bloch basis set consists of valence orbitals (3d, 4s, and 4p states for transition metals) orthogonalized to the frozen-core wave functions. The self-consistent potential is obtained iteratively within the superposition of overlapping spherical atomic charge density model with the atomic configurations treated as adjustable parameters. Thus the crystal Coulomb potential is constructed as a superposition of overlapping spherically symmetric atomic potentials and, correspondingly, the local density Kohn-Sham (α = 2/3) potential is determined from a superposition of atomic charge densities. At each iteration in the self-consistency procedure, the crystal charge density is evaluated using a sampling of 15 independent k points in (1/8)th of the irreducible two-dimensional Brillouin zone. The total density of states (DOS) and projected local DOS (by layer plane) are calculated using an analytic linear energy triangle method (presented as an Appendix) generalized from the tetrahedron scheme for bulk systems. Distinct differences are obtained between the surface and central plane local DOS. The central plane DOS is found to converge rapidly to the DOS of bulk paramagnetic Ni obtained by Wang and Callaway. Only a very small surplus charge (0.03 electron/atom) is found on the surface planes, in agreement with jellium model calculations

Spatio-temporal variation in age structure and abundance of the endangered snail kite: Pooling across regions masks a declining and aging population

Science.gov (United States)

Reichert, Brian E.; Kendall, William L.; Fletcher, Robert J.; Kitchens, Wiley M.

2016-01-01

While variation in age structure over time and space has long been considered important for population dynamics and conservation, reliable estimates of such spatio-temporal variation in age structure have been elusive for wild vertebrate populations. This limitation has arisen because of problems of imperfect detection, the potential for temporary emigration impacting assessments of age structure, and limited information on age. However, identifying patterns in age structure is important for making reliable predictions of both short- and long-term dynamics of populations of conservation concern. Using a multistate superpopulation estimator, we estimated region-specific abundance and age structure (the proportion of individuals within each age class) of a highly endangered population of snail kites for two separate regions in Florida over 17 years (1997–2013). We find that in the southern region of the snail kite—a region known to be critical for the long-term persistence of the species—the population has declined significantly since 1997, and during this time, it has increasingly become dominated by older snail kites (> 12 years old). In contrast, in the northern region—a region historically thought to serve primarily as drought refugia—the population has increased significantly since 2007 and age structure is more evenly distributed among age classes. Given that snail kites show senescence at approximately 13 years of age, where individuals suffer higher mortality rates and lower breeding rates, these results reveal an alarming trend for the southern region. Our work illustrates the importance of accounting for spatial structure when assessing changes in abundance and age distribution and the need for monitoring of age structure in imperiled species.

The rate-size trade-off structures intraspecific variation in Daphnia ambigua life history parameters.

Science.gov (United States)

DeLong, John P; Hanley, Torrance C

2013-01-01

The identification of trade-offs is necessary for understanding the evolution and maintenance of diversity. Here we employ the supply-demand (SD) body size optimization model to predict a trade-off between asymptotic body size and growth rate. We use the SD model to quantitatively predict the slope of the relationship between asymptotic body size and growth rate under high and low food regimes and then test the predictions against observations for Daphnia ambigua. Close quantitative agreement between observed and predicted slopes at both food levels lends support to the model and confirms that a 'rate-size' trade-off structures life history variation in this population. In contrast to classic life history expectations, growth and reproduction were positively correlated after controlling for the rate-size trade-off. We included 12 Daphnia clones in our study, but clone identity explained only some of the variation in life history traits. We also tested the hypothesis that growth rate would be positively related to intergenic spacer length (i.e. the growth rate hypothesis) across clones, but we found that clones with intermediate intergenic spacer lengths had larger asymptotic sizes and slower growth rates. Our results strongly support a resource-based optimization of body size following the SD model. Furthermore, because some resource allocation decisions necessarily precede others, understanding interdependent life history traits may require a more nested approach.

The rate-size trade-off structures intraspecific variation in Daphnia ambigua life history parameters.

Directory of Open Access Journals (Sweden)

John P DeLong

Full Text Available The identification of trade-offs is necessary for understanding the evolution and maintenance of diversity. Here we employ the supply-demand (SD body size optimization model to predict a trade-off between asymptotic body size and growth rate. We use the SD model to quantitatively predict the slope of the relationship between asymptotic body size and growth rate under high and low food regimes and then test the predictions against observations for Daphnia ambigua. Close quantitative agreement between observed and predicted slopes at both food levels lends support to the model and confirms that a 'rate-size' trade-off structures life history variation in this population. In contrast to classic life history expectations, growth and reproduction were positively correlated after controlling for the rate-size trade-off. We included 12 Daphnia clones in our study, but clone identity explained only some of the variation in life history traits. We also tested the hypothesis that growth rate would be positively related to intergenic spacer length (i.e. the growth rate hypothesis across clones, but we found that clones with intermediate intergenic spacer lengths had larger asymptotic sizes and slower growth rates. Our results strongly support a resource-based optimization of body size following the SD model. Furthermore, because some resource allocation decisions necessarily precede others, understanding interdependent life history traits may require a more nested approach.

Pluck or Luck: Does Trait Variation or Chance Drive Variation in Lifetime Reproductive Success?

Science.gov (United States)

Snyder, Robin E; Ellner, Stephen P

2018-04-01

While there has been extensive interest in how intraspecific trait variation affects ecological processes, outcomes are highly variable even when individuals are identical: some are lucky, while others are not. Trait variation is therefore important only if it adds substantially to the variability produced by luck. We ask when trait variation has a substantial effect on variability in lifetime reproductive success (LRS), using two approaches: (1) we partition the variation in LRS into contributions from luck and trait variation and (2) we ask what can be inferred about an individual's traits and with what certainty, given their observed LRS. In theoretical stage- and size-structured models and two empirical case studies, we find that luck usually dominates the variance of LRS. Even when individuals differ substantially in ways that affect expected LRS, unless the effects of luck are substantially reduced (e.g., low variability in reproductive life span or annual fecundity), most variance in lifetime outcomes is due to luck, implying that departures from "null" models omitting trait variation will be hard to detect. Luck also obscures the relationship between realized LRS and individual traits. While trait variation may influence the fate of populations, luck often governs the lives of individuals.

Population and evolutionary dynamics in spatially structured seasonally varying environments.

Science.gov (United States)

Reid, Jane M; Travis, Justin M J; Daunt, Francis; Burthe, Sarah J; Wanless, Sarah; Dytham, Calvin

2018-03-25

Increasingly imperative objectives in ecology are to understand and forecast population dynamic and evolutionary responses to seasonal environmental variation and change. Such population and evolutionary dynamics result from immediate and lagged responses of all key life-history traits, and resulting demographic rates that affect population growth rate, to seasonal environmental conditions and population density. However, existing population dynamic and eco-evolutionary theory and models have not yet fully encompassed within-individual and among-individual variation, covariation, structure and heterogeneity, and ongoing evolution, in a critical life-history trait that allows individuals to respond to seasonal environmental conditions: seasonal migration. Meanwhile, empirical studies aided by new animal-tracking technologies are increasingly demonstrating substantial within-population variation in the occurrence and form of migration versus year-round residence, generating diverse forms of 'partial migration' spanning diverse species, habitats and spatial scales. Such partially migratory systems form a continuum between the extreme scenarios of full migration and full year-round residence, and are commonplace in nature. Here, we first review basic scenarios of partial migration and associated models designed to identify conditions that facilitate the maintenance of migratory polymorphism. We highlight that such models have been fundamental to the development of partial migration theory, but are spatially and demographically simplistic compared to the rich bodies of population dynamic theory and models that consider spatially structured populations with dispersal but no migration, or consider populations experiencing strong seasonality and full obligate migration. Second, to provide an overarching conceptual framework for spatio-temporal population dynamics, we define a 'partially migratory meta-population' system as a spatially structured set of locations that can

Invariant sets for Windows

CERN Document Server

Morozov, Albert D; Dragunov, Timothy N; Malysheva, Olga V

1999-01-01

This book deals with the visualization and exploration of invariant sets (fractals, strange attractors, resonance structures, patterns etc.) for various kinds of nonlinear dynamical systems. The authors have created a special Windows 95 application called WInSet, which allows one to visualize the invariant sets. A WInSet installation disk is enclosed with the book.The book consists of two parts. Part I contains a description of WInSet and a list of the built-in invariant sets which can be plotted using the program. This part is intended for a wide audience with interests ranging from dynamical

[Variations of structure and of flora of the "carrasco" vegetation of the Ibiapaba plateau, state of Cearsá, Brazil].

Science.gov (United States)

de Araújo, F S; Martins, F R; Shepherd, G J

1999-11-01

"Carrasco" is a closed, tall-shrubby, xerophilous vegetation on Quartz Sand soils between altitudes of 700 and 900 m on Ibiapaba and Araripe plateaus in the Brazilian semi-arid domain. As it is still very poorly known, this paper aims to describe the structure and composition of the woody community and its spatial variation in relation to the soil. One-hundred 10 x 10 m plots were located by pairs of random numbers in a coordinate system at the locality of Jaburuna (3 degrees 54'34"S, 40 degrees 59'24"W, about 830 m altitude), municipality of Ubajara, north Ibiapaba. All woody plants with a minimum stem diameter of 3 cm at ground level had their vertical height (not for climbers) and stem perimeter recorded. A soil extract from 0-50 cm depth was taken at the centre of each plot. Published surveys of other carrasco areas on the south Ibiapaba were considered for comparison. The community structure showed great dominance concentration, the most abundant species (Acacia langsdorffii, Piptadenia moniliformis, Thiloa glaucocarpa) varied between surveys. At Jaburuna 81% of all sampled plants were shrubs, 14% trees (the most with less than 10 cm of trunk diameter and 6 m height), and 5% climbers. Canberra distances and Jaccard's Indices were calculated from a primary matrix of 87 species (with 5 or more individuals) and 175 plots. Several methods of cluster analysis were employed, all showed great floristic variation from place to place. A matrix of soil physical and chemical variates per plot was constructed, and the canonical correspondence analysis was applied to both primary and soil matrices. Lower pH and higher sum of bases (e. g. Brunfelsia cuneifolia, Neojeobertia candoleana), higher content of gross sand (e. g. Acacia glomerosa, Aspidosperma subincanumn) and higher content of fine sand (e. g. Aspidosperma discolor, Hymenaea velutina) were the main variates separating species. The floristic richness at Jaburuna was of 74 species, and the surveys showed no

Ab initio localized basis set study of structural parameters and elastic properties of HfO{sub 2} polymorphs

Energy Technology Data Exchange (ETDEWEB)

Caravaca, M A [Facultad de Ingenieria, Universidad Nacional del Nordeste, Avenida Las Heras 727, 3500-Resistencia (Argentina); Casali, R A [Facultad de Ciencias Exactas y Naturales y Agrimensura, Universidad Nacional del Nordeste, Avenida Libertad, 5600-Corrientes (Argentina)

2005-09-21

The SIESTA approach based on pseudopotentials and a localized basis set is used to calculate the electronic, elastic and equilibrium properties of P 2{sub 1}/c, Pbca, Pnma, Fm3m, P4{sub 2}nmc and Pa3 phases of HfO{sub 2}. Using separable Troullier-Martins norm-conserving pseudopotentials which include partial core corrections for Hf, we tested important physical properties as a function of the basis set size, grid size and cut-off ratio of the pseudo-atomic orbitals (PAOs). We found that calculations in this oxide with the LDA approach and using a minimal basis set (simple zeta, SZ) improve calculated phase transition pressures with respect to the double-zeta basis set and LDA (DZ-LDA), and show similar accuracy to that determined with the PPPW and GGA approach. Still, the equilibrium volumes and structural properties calculated with SZ-LDA compare better with experiments than the GGA approach. The bandgaps and elastic and structural properties calculated with DZ-LDA are accurate in agreement with previous state of the art ab initio calculations and experimental evidence and cannot be improved with a polarized basis set. These calculated properties show low sensitivity to the PAO localization parameter range between 40 and 100 meV. However, this is not true for the relative energy, which improves upon decrease of the mentioned parameter. We found a non-linear behaviour in the lattice parameters with pressure in the P 2{sub 1}/c phase, showing a discontinuity of the derivative of the a lattice parameter with respect to external pressure, as found in experiments. The common enthalpy values calculated with the minimal basis set give pressure transitions of 3.3 and 10.8?GPa for P2{sub 1}/c {yields} Pbca and Pbca {yields} Pnma, respectively, in accordance with different high pressure experimental values.

Insights into the genome structure and copy-number variation of Eimeria tenella

Directory of Open Access Journals (Sweden)

Lim Lik-Sin

2012-08-01

method to improve the assembly of the genome of E. tenella from shotgun data, and to help reveal its overall structure. A preliminary assessment of copy-number variation (extra or missing copies of genomic segments between strains of E. tenella was also carried out. The emerging picture is of a very unusual genome architecture displaying inter-strain copy-number variation. We suggest that these features may be related to the known ability of this parasite to rapidly develop drug resistance.

Structural variations of chromosome 1 R from rye cultivar Jingzhouheimai induced by irradiation

International Nuclear Information System (INIS)

Wang Conglei; Zhuang Lifang; Qi Zengjun

2012-01-01

Irradiated with 60 Co γ-rays (12 Gy), the pollen of wheat landrace Huixianhong-Secale cereal cv. Jingzhouheimai DA1R was pollinated to the emasculated spikes of Huixianhong. Analyzed with genomic in situ hybridization GISH using gDNA of rye cv. Jingzhouheimai as a probe, four plants with reciprocal translocation, four plants with large segmental translocation and one plant with distal segmental translocation, one plant with one telocentric chromosome were identified from 33 M 1 seeds. The results showed that the translocation frequency was 30.30% and of the total 11 breakage-fusion events, 1 involved centric regions and 10 involved interstitial regions. The experiment showed that pollen irradiation was an effective method to induce wheat alien chromosomal structural variations which could effectively by used in deletion mapping, chromosomal location of important agronomic genes and development of small segmental translocations with target genes. (authors)

Variations in the small-scale galactic magnetic field and short time-scale intensity variations of extragalactic radio sources

International Nuclear Information System (INIS)

Simonetti, J.H.

1985-01-01

Structure functions of the Faraday rotation measures (RMs) of extragalactic radio sources are used to investigate variations in the interstellar magnetic field on length scales of approx.0.01 to 100 pc. Model structure functions derived assuming a power-law power spectrum of irregularities in n/sub e/B, are compared with those observed. The results indicate an outer angular scale for RM variations of approximately less than or equal to 5 0 and evidence for RM variations on scales as small as 1'. Differences in the variance of n/sub e/B fluctuations for various lines of sight through the Galaxy are found. Comparison of pulsar scintillations in right- and left-circular polarizations yield an upper limit to the variations in n/sub e/ on a length scale of approx.10 11 cm. RMs were determined through high-velocity molecular flows in galactic star-formation regions, with the goal of constraining magnetic fields in and near the flows. RMs of 7 extragalactic sources with a approx.20 arcmin wide area seen through Cep A, fall in two groups separated by approx.150 rad m -2 - large given our knowledge of RM variations on small angular scales and possibly a result of the anisotropy of the high-velocity material

Reactive solid surface morphology variation via ionic diffusion.

Science.gov (United States)

Sun, Zhenchao; Zhou, Qiang; Fan, Liang-Shih

2012-08-14

In gas-solid reactions, one of the most important factors that determine the overall reaction rate is the solid morphology, which can be characterized by a combination of smooth, convex and concave structures. Generally, the solid surface structure varies in the course of reactions, which is classically noted as being attributed to one or more of the following three mechanisms: mechanical interaction, molar volume change, and sintering. Here we show that if a gas-solid reaction involves the outward ionic diffusion of a solid-phase reactant then this outward ionic diffusion could eventually smooth the surface with an initial concave and/or convex structure. Specifically, the concave surface is filled via a larger outward diffusing surface pointing to the concave valley, whereas the height of the convex surface decreases via a lower outward diffusion flux in the vertical direction. A quantitative 2-D continuum diffusion model is established to analyze these two morphological variation processes, which shows consistent results with the experiments. This surface morphology variation by solid-phase ionic diffusion serves to provide a fourth mechanism that supplements the traditionally acknowledged solid morphology variation or, in general, porosity variation mechanisms in gas-solid reactions.

On minimizers of causal variational principles

International Nuclear Information System (INIS)

Schiefeneder, Daniela

2011-01-01

Causal variational principles are a class of nonlinear minimization problems which arise in a formulation of relativistic quantum theory referred to as the fermionic projector approach. This thesis is devoted to a numerical and analytic study of the minimizers of a general class of causal variational principles. We begin with a numerical investigation of variational principles for the fermionic projector in discrete space-time. It is shown that for sufficiently many space-time points, the minimizing fermionic projector induces non-trivial causal relations on the space-time points. We then generalize the setting by introducing a class of causal variational principles for measures on a compact manifold. In our main result we prove under general assumptions that the support of a minimizing measure is either completely timelike, or it is singular in the sense that its interior is empty. In the examples of the circle, the sphere and certain flag manifolds, the general results are supplemented by a more detailed analysis of the minimizers. (orig.)

Vertical Structural Variation and Their Development of the Sanukayama Rhyolite Lava in Kozushima Island, Japan

Science.gov (United States)

Furukawa, K.; Uno, K.; Kanamaru, T.; Nakai, K.

2017-12-01

We revealed structural development of the Pleistocene Sanukayama rhyolite lava of Kozushima Island, Japan. The good exposure, with about 130 m thick, provides valuable opportunity to understand the vertical structural variation. This exposure corresponds to the upper half of the lava. The paleomagnetic results show that the lava emplaced in subaerial condition at least in the exposed part. The vertical lithofacies are divided into the pumiceous (25-40 m thick), obsidian (40-60 m), spherulitic (30-50 m) layers from top to base. The pumiceous layer is characterized by massive foliated pumice. The foliation dips are gradually changed from gentle (10-30°) in lower part to steep (around 90°) in upper part. This shows the balloon-like morphology. The massive pumiceous layer would be generated from late stage diapiric inflation of the lava (Fink and Manley, 1987). The obsidian layer is composed of massive and welded-brecciated parts. The ductile-deformed light-colored veins, with a few mm thick, are frequently developed. In the microscopic observation, the veins are composed of broken crystals and obsidian clasts indicating fracturing of the lava followed by ductile deformation such as the RFH process (Tuffen et al., 2003). In this layer, extensive vesiculation and microlite development must have been prevented by higher load pressure and faster cooling, respectively. Consequently, they resulted in formation of the obsidian. The spherulitic layer is characterized by development of the ductile-deformed flow banding. The microscopic observation shows that the bands are formed by the spherulite trail. Furthermore, the microlites are aligned within the spherulites. In the heat-retained inner part of the lava, microlites would be developed around the healed fractures. The microlites acted as nucleation site of spherulite. In transition layer between obsidian and spherulitic layers (obsidian layer. This would be caused by high flow-induced shear arising from their rheological

Morphological Variation and Ecological Structure of Iroko (Milicia excelsa Welw. C.C. Berg) Populations across Different Bio geographical Zones in Benin

International Nuclear Information System (INIS)

Ouinsavi, C.; Sokpon, N.

2010-01-01

Iroko (Milicia excelsa) is a commercially important timber tree species formerly known by local people in Benin. Because of the highly attractive technological properties of its wood and its multipurpose uses, the species was subjected to intensive human pressure. Apart from strong climate oscillation during the Pleistocene, human caused habitat fragmentation through continuous land clearing for agriculture, extensive forests exploitation and urbanization induced the occurrence of many isolated forest plots and trees species among which Milicia excelsa trees. As fragmentation was proved to have deleterious effects on genetic diversity within a species and its morphological structure, it was of interest to investigate the current demographic, morphological and genetic structure of M. excelsa before coming up with conservation strategies. In the current study, morphological variation and ecological structure of M. excelsa populations were assessed in Benin using transect sampling method and multivariate analyses including principal component, cluster and canonical discriminant analyses. On the basis of morphological parameters, M. excelsa individuals and populations were clustered into four and discrimination of groups indicated that most of variations were highly related to edaphic factors and annual rainfall. Erratic diameter distribution was found for many populations although most of them showed bell shaped diameter distribution.

Factors affecting yearly variations of indoor radon concentrations

International Nuclear Information System (INIS)

Steck, D.J.; Baynes, S.A.

1996-01-01

Since indoor radon exposures take place over many years while radon measurement periods are shorter, we are studying the yearly variation of indoor radon concentrations in approximately 100 houses located throughout Minnesota. Most houses were initially measured for one or more years in the late 1980's and for 5 consecutive years starting in 1990. Two houses have been monitored for 12 y. Each year, two alpha track detectors were placed on the two lowest livable levels. The year-to-year variations averaged about 35% (corrected for instrumental uncertainties) in both basements and first floors. The minimum observed variation was 5% and the maximum was 130%. Some homes have shown substantial variation associated with Structural modifications. While most homes show no obvious systematic trends, a few houses have shown temporal trends that may be associated with aging or climate. We are studying possible correlation between year-to-year radon variation, climatic variables (yearly-average and seasonal such as heating/cooling degree days, precipitation, soil moisture), and structural changes

Composition and structure variation for magnetron sputtered tantalum oxynitride thin films, as function of deposition parameters

Energy Technology Data Exchange (ETDEWEB)

Cristea, D.; Pătru, M.; Crisan, A.; Munteanu, D. [Department of Materials Science, Transilvania University, 500036 Brasov (Romania); Crăciun, D. [Laser Department, National Institute for Laser, Plasma, and Radiation Physics, Magurele (Romania); Barradas, N.P. [Centro de Ciências e Tecnologias Nucleares, Instituto Superior Técnico, Universidade de Lisboa, E.N. 10 ao km 139,7, 2695-066 Bobadela LRS (Portugal); Alves, E. [Instituto de Plasmas e Fusão Nuclear, Instituto Superior Técnico, Universidade de Lisboa, E.N. 10 ao km 139,7, 2695-066 Bobadela LRS (Portugal); Apreutesei, M. [Université de Lyon, Institut des Nanotechnologies de Lyon INL-UMR 5270, CNRS, Ecole Centrale de Lyon, Ecully F-69134 (France); MATEIS Laboratory-INSA de Lyon, Bât. B. Pascal, 7 Avenue Jean Capelle, 69621 Villeurbanne Cedex (France); Moura, C. [Center of Physics, University of Minho, Campus de Gualtar, 4710-057 Braga (Portugal); Cunha, L., E-mail: lcunha@fisica.uminho.pt [Center of Physics, University of Minho, Campus de Gualtar, 4710-057 Braga (Portugal)

2015-12-15

Highlights: • Structural evolution from β-Ta, to fcc-Ta(O,N), to amorphous Ta{sub 2}O{sub 5} with increasing P(N{sub 2} + O{sub 2}). • The substrate bias influences the N content, but does not influence the O content of the films. • The structural features of the films appear at lower P(N{sub 2} + O{sub 2}) when produced with grounded substrate. - Abstract: Tantalum oxynitride thin films were produced by magnetron sputtering. The films were deposited using a pure Ta target and a working atmosphere with a constant N{sub 2}/O{sub 2} ratio. The choice of this constant ratio limits the study concerning the influence of each reactive gas, but allows a deeper understanding of the aspects related to the affinity of Ta to the non-metallic elements and it is economically advantageous. This work begins by analysing the data obtained directly from the film deposition stage, followed by the analysis of the morphology, composition and structure. For a better understanding regarding the influence of the deposition parameters, the analyses are presented by using the following criterion: the films were divided into two sets, one of them produced with grounded substrate holder and the other with a polarization of −50 V. Each one of these sets was produced with different partial pressure of the reactive gases P(N{sub 2} + O{sub 2}). All the films exhibited a O/N ratio higher than the N/O ratio in the deposition chamber atmosphere. In the case of the films produced with grounded substrate holder, a strong increase of the O content is observed, associated to the strong decrease of the N content, when P(N{sub 2} + O{sub 2}) is higher than 0.13 Pa. The higher Ta affinity for O strongly influences the structural evolution of the films. Grazing incidence X-ray diffraction showed that the lower partial pressure films were crystalline, while X-ray reflectivity studies found out that the density of the films depended on the deposition conditions: the higher the gas pressure, the

The international Genome sample resource (IGSR): A worldwide collection of genome variation incorporating the 1000 Genomes Project data.

Science.gov (United States)

Clarke, Laura; Fairley, Susan; Zheng-Bradley, Xiangqun; Streeter, Ian; Perry, Emily; Lowy, Ernesto; Tassé, Anne-Marie; Flicek, Paul

2017-01-04

The International Genome Sample Resource (IGSR; http://www.internationalgenome.org) expands in data type and population diversity the resources from the 1000 Genomes Project. IGSR represents the largest open collection of human variation data and provides easy access to these resources. IGSR was established in 2015 to maintain and extend the 1000 Genomes Project data, which has been widely used as a reference set of human variation and by researchers developing analysis methods. IGSR has mapped all of the 1000 Genomes sequence to the newest human reference (GRCh38), and will release updated variant calls to ensure maximal usefulness of the existing data. IGSR is collecting new structural variation data on the 1000 Genomes samples from long read sequencing and other technologies, and will collect relevant functional data into a single comprehensive resource. IGSR is extending coverage with new populations sequenced by collaborating groups. Here, we present the new data and analysis that IGSR has made available. We have also introduced a new data portal that increases discoverability of our data-previously only browseable through our FTP site-by focusing on particular samples, populations or data sets of interest. © The Author(s) 2016. Published by Oxford University Press on behalf of Nucleic Acids Research.

On the sighting of unicorns: A variational approach to computing invariant sets in dynamical systems

Science.gov (United States)

Junge, Oliver; Kevrekidis, Ioannis G.

2017-06-01

We propose to compute approximations to invariant sets in dynamical systems by minimizing an appropriate distance between a suitably selected finite set of points and its image under the dynamics. We demonstrate, through computational experiments, that this approach can successfully converge to approximations of (maximal) invariant sets of arbitrary topology, dimension, and stability, such as, e.g., saddle type invariant sets with complicated dynamics. We further propose to extend this approach by adding a Lennard-Jones type potential term to the objective function, which yields more evenly distributed approximating finite point sets, and illustrate the procedure through corresponding numerical experiments.

Spatio-Temporal Patterns in the Coral Reef Communities of the Spermonde Archipelago, 2012–2014, II: Fish Assemblages Display Structured Variation Related to Benthic Condition

Directory of Open Access Journals (Sweden)

Jeremiah G. Plass-Johnson

2018-02-01

Full Text Available The Spermonde Archipelago is a complex of ~70 mostly populated islands off Southwest Sulawesi, Indonesia, in the center of the Coral Triangle. The reefs in this area are exposed to a high level of anthropogenic disturbances. Previous studies have shown that variation in the benthos is strongly linked to water quality and distance from the mainland. However, little is known about the fish assemblages of the region and if their community structure also follows a relationship with benthic structure and distance from shore. In this study, we used eight islands of the archipelago, varying in distance from 1 to 55 km relative to the mainland, and 3 years of surveys, to describe benthic and fish assemblages and to examine the spatial and temporal influence of benthic composition on the structure of the fish assemblages. Cluster analysis indicated that distinct groups of fish were associated with distance, while few species were present across the entire range of sites. Relating fish communities to benthic composition using a multivariate generalized linear model confirmed that fish groups relate to structural complexity (rugosity or differing benthic groups; either algae, reef builders (coral and crustose coralline algae or invertebrates and rubble. From these relationships we can identify sets of fish species that may be lost given continued degradation of the Spermonde reefs. Lastly, the incorporation of water quality, benthic and fish indices indicates that local coral reefs responded positively after an acute disturbance in 2013 with increases in reef builders and fish diversity over relatively short (1 year time frames. This study contributes an important, missing component (fish community structure to the growing literature on the Spermonde Archipelago, a system that features environmental pressures common in the greater Southeast Asian region.

Continuation of Sets of Constrained Orbit Segments

DEFF Research Database (Denmark)

Schilder, Frank; Brøns, Morten; Chamoun, George Chaouki

Sets of constrained orbit segments of time continuous flows are collections of trajectories that represent a whole or parts of an invariant set. A non-trivial but simple example is a homoclinic orbit. A typical representation of this set consists of an equilibrium point of the flow and a trajectory...... that starts close and returns close to this fixed point within finite time. More complicated examples are hybrid periodic orbits of piecewise smooth systems or quasi-periodic invariant tori. Even though it is possible to define generalised two-point boundary value problems for computing sets of constrained...... orbit segments, this is very disadvantageous in practice. In this talk we will present an algorithm that allows the efficient continuation of sets of constrained orbit segments together with the solution of the full variational problem....

Morphological, Structural and Optical Evolution of Ag Nanostructures on c-Plane GaN Through the Variation of Deposition Amount and Temperature

Science.gov (United States)

Sui, Mao; Li, Ming-Yu; Pandey, Puran; Zhang, Quanzhen; Kunwar, Sundar; Lee, Jihoon

2018-03-01

Owing to their tunable properties, Ag nanostructures have been widely adapted in various applications and the morphological control can determine their performance and effectiveness. In this work, we demonstrate the morphological and optical evolution of Ag nanostructures on GaN (0001) by the systematic control of deposition amount at two distinctive annealing temperatures. Based on the Volmer-Weber and coalescence growth models, the nanostructure growth commenced by the thermal solid-state-dewetting evolve in terms of size, density and configuration. At 450 °C, the round-dome shaped Ag nanoparticles (regime I), irregular Ag nano-mounds (regime II) and void-layer structures (regime III) are observed along with the gradually increased deposition amount. As a sharp distinction, the solid state dewetting process occur more radically at 700 °C and also, the Ag sublimation and the effect on the nanostructure formation are observed in a clear regime shift scaled by the deposition amount. Meanwhile, a strong dependency of reflectance spectra evolution on the Ag nanostructure morphology is witnessed for both sets. In particular, Ag dipolar resonance peaks are significantly red-shifted from VIS to NIR regions along with the nanostructure evolution. The reflectance, PL and Raman intensity variation are also observed and discussed based on the evolution of Ag nanostructures.

Genomic structural variation-mediated allelic suppression causes hybrid male sterility in rice.

Science.gov (United States)

Shen, Rongxin; Wang, Lan; Liu, Xupeng; Wu, Jiang; Jin, Weiwei; Zhao, Xiucai; Xie, Xianrong; Zhu, Qinlong; Tang, Huiwu; Li, Qing; Chen, Letian; Liu, Yao-Guang

2017-11-03

Hybrids between divergent populations commonly show hybrid sterility; this reproductive barrier hinders hybrid breeding of the japonica and indica rice (Oryza sativa L.) subspecies. Here we show that structural changes and copy number variation at the Sc locus confer japonica-indica hybrid male sterility. The japonica allele, Sc-j, contains a pollen-essential gene encoding a DUF1618-domain protein; the indica allele, Sc-i, contains two or three tandem-duplicated ~ 28-kb segments, each carrying an Sc-j-homolog with a distinct promoter. In Sc-j/Sc-i hybrids, the high-expression of Sc-i in sporophytic cells causes suppression of Sc-j expression in pollen and selective abortion of Sc-j-pollen, leading to transmission ratio distortion. Knocking out one or two of the three Sc-i copies by CRISPR/Cas9 rescues Sc-j expression and male fertility. Our results reveal the gene dosage-dependent allelic suppression as a mechanism of hybrid incompatibility, and provide an effective approach to overcome the reproductive barrier for hybrid breeding.

Resonances, cusp effects and a virtual state in e/sup -/-He scattering near the n = 3 thresholds. [Variational methods, resonance, threshold structures

Energy Technology Data Exchange (ETDEWEB)

Nesbet, R K [International Business Machines Corp., San Jose, Calif. (USA). Research Lab.

1978-01-14

Variational calculations locate and identify resonances and new threshold structures in electron impact excitation of He metastable states, in the region of the 3/sup 3/S and 3/sup 1/S excitation thresholds. A virtual state is found at the 3/sup 3/S threshold.

Variational continuum multiphase poroelasticity theory and applications

CERN Document Server

Serpieri, Roberto

2017-01-01

This book collects the theoretical derivation of a recently presented general variational macroscopic continuum theory of multiphase poroelasticity (VMTPM), together with its applications to consolidation and stress partitioning problems of interest in several applicative engineering contexts, such as in geomechanics and biomechanics. The theory is derived based on a purely-variational deduction, rooted in the least-Action principle, by considering a minimal set of kinematic descriptors. The treatment herein considered keeps a specific focus on the derivation of most general medium-independent governing equations. It is shown that VMTPM recovers paradigms of consolidated use in multiphase poroelasticity such as Terzaghi's stress partitioning principle and Biot's equations for wave propagation. In particular, the variational treatment permits the derivation of a general medium-independent stress partitioning law, and the proposed variational theory predicts that the external stress, the fluid pressure, and the...

Variational principles for the projected breakup amplitude

International Nuclear Information System (INIS)

Hahn, Y.

1976-01-01

Two alternate forms of variational principles for the breakup amplitude describing the two- to three-cluster transition are derived such that all the integrals involved in the intermediate stages are well defined. The first form contains a trial Green's function with which both the initial and final state trial wave functions are constructed. The earlier form of the Kohn-type variational principle derived by Lieber, Rosenberg, and Spruch is recovered, however, when this connection between the trial functions is removed. The second form of the variational principle is derived by projecting out from the trial functions all the open channel components which correspond to the two-cluster structures including the rearrangement channels. The remaining part of the wave functions describes the channels with three-cluster structures, and the integrals involving this part are then mathematically well defined

Anatomic variations of the cochlea and relations to other temporal bone structures

Energy Technology Data Exchange (ETDEWEB)

Dimopoulos, P.; Muren, C. (Akademiska Sjukhuset, Uppsala (Sweden). Dept. of Diagnostic Radiology Sabbatsberg' s Sjukhus, Stockholm (Sweden). Dept. of Diagnostic Radiology)

1990-09-01

The size and shape of the human cochlea and the normal ranges of variation of its dimensions were evaluated in 95 plastic casts, prepared from temporal bone specimens. The normal range of variation is fairly small, and is not age-dependent. Obvious digression from this range, associated with pertinent clinical symptoms, indicates an abnormality. (orig./MG).

Dynamic asset trees in the US stock market: Structure variation and market phenomena

International Nuclear Information System (INIS)

Huang, Wei-Qiang; Yao, Shuang; Zhuang, Xin-Tian; Yuan, Ying

2017-01-01

In this work, employing a moving window to scan through every stock price time series over a period from 2 January 1986 to 20 October 2015, we use cross-correlations to measure the interdependence between stock prices, and we construct a corresponding minimal spanning tree for 170 U.S. stocks in every given window. We show how the asset tree evolves over time and describe the dynamics of its normalized length, centrality measures, vertex degree and vertex strength distributions, and single- and multiple-step edge survival ratios. We find that the normalized tree length shows a tendency to decrease over the 30 years. The power-law of vertex degree or vertex strength distribution does not hold for all trees. The survival ratio analysis reveals an increased stability of the dependence structure of the stock market as time elapses. We then examine the relationship between tree structure variation and market phenomena, such as average, volatility and tail risk of stock (market) return. Our main observation is that the normalized tree length has a positive relationship with the level of stock market average return, and it responds negatively to the market return volatility and tail risk. Furthermore, the majority of stocks have their vertex degrees significantly positively correlated to their average return, and significantly negatively correlated to their return volatility and tail risk.

Variations in the Circumplex Structure of Mood.

Science.gov (United States)

Feldman, Lisa A.

1995-01-01

Researchers have emphasized the similarity of the semantic and self-report mood circumplexes. Study investigated systematic differences in theses structures. Demonstrated that when making judgments of their mood, people weigh the arousal dimension less than the valence dimension. Dimensions are weighed equally in semantic structure. (JBJ)

Transport equations, Level Set and Eulerian mechanics. Application to fluid-structure coupling

International Nuclear Information System (INIS)

Maitre, E.

2008-11-01

My works were devoted to numerical analysis of non-linear elliptic-parabolic equations, to neutron transport equation and to the simulation of fabrics draping. More recently I developed an Eulerian method based on a level set formulation of the immersed boundary method to deal with fluid-structure coupling problems arising in bio-mechanics. Some of the more efficient algorithms to solve the neutron transport equation make use of the splitting of the transport operator taking into account its characteristics. In the present work we introduced a new algorithm based on this splitting and an adaptation of minimal residual methods to infinite dimensional case. We present the case where the velocity space is of dimension 1 (slab geometry) and 2 (plane geometry) because the splitting is simpler in the former

Cerebral perfusion computed tomography deconvolution via structure tensor total variation regularization

Energy Technology Data Exchange (ETDEWEB)

Zeng, Dong; Zhang, Xinyu; Bian, Zhaoying, E-mail: zybian@smu.edu.cn, E-mail: jhma@smu.edu.cn; Huang, Jing; Zhang, Hua; Lu, Lijun; Lyu, Wenbing; Feng, Qianjin; Chen, Wufan; Ma, Jianhua, E-mail: zybian@smu.edu.cn, E-mail: jhma@smu.edu.cn [Department of Biomedical Engineering, Southern Medical University, Guangzhou, Guangdong 510515, China and Guangdong Provincial Key Laboratory of Medical Image Processing, Southern Medical University, Guangzhou, Guangdong 510515 (China); Zhang, Jing [Department of Radiology, Tianjin Medical University General Hospital, Tianjin 300052 (China)

2016-05-15

Purpose: Cerebral perfusion computed tomography (PCT) imaging as an accurate and fast acute ischemic stroke examination has been widely used in clinic. Meanwhile, a major drawback of PCT imaging is the high radiation dose due to its dynamic scan protocol. The purpose of this work is to develop a robust perfusion deconvolution approach via structure tensor total variation (STV) regularization (PD-STV) for estimating an accurate residue function in PCT imaging with the low-milliampere-seconds (low-mAs) data acquisition. Methods: Besides modeling the spatio-temporal structure information of PCT data, the STV regularization of the present PD-STV approach can utilize the higher order derivatives of the residue function to enhance denoising performance. To minimize the objective function, the authors propose an effective iterative algorithm with a shrinkage/thresholding scheme. A simulation study on a digital brain perfusion phantom and a clinical study on an old infarction patient were conducted to validate and evaluate the performance of the present PD-STV approach. Results: In the digital phantom study, visual inspection and quantitative metrics (i.e., the normalized mean square error, the peak signal-to-noise ratio, and the universal quality index) assessments demonstrated that the PD-STV approach outperformed other existing approaches in terms of the performance of noise-induced artifacts reduction and accurate perfusion hemodynamic maps (PHM) estimation. In the patient data study, the present PD-STV approach could yield accurate PHM estimation with several noticeable gains over other existing approaches in terms of visual inspection and correlation analysis. Conclusions: This study demonstrated the feasibility and efficacy of the present PD-STV approach in utilizing STV regularization to improve the accuracy of residue function estimation of cerebral PCT imaging in the case of low-mAs.

A New Approximation Method for Solving Variational Inequalities and Fixed Points of Nonexpansive Mappings

Directory of Open Access Journals (Sweden)

Klin-eam Chakkrid

2009-01-01

Full Text Available Abstract A new approximation method for solving variational inequalities and fixed points of nonexpansive mappings is introduced and studied. We prove strong convergence theorem of the new iterative scheme to a common element of the set of fixed points of nonexpansive mapping and the set of solutions of the variational inequality for the inverse-strongly monotone mapping which solves some variational inequalities. Moreover, we apply our main result to obtain strong convergence to a common fixed point of nonexpansive mapping and strictly pseudocontractive mapping in a Hilbert space.

Intercomparison of JAERI Torso Phantom lung sets

International Nuclear Information System (INIS)

Kramer, Gary H.; Hauck, Barry M.

2000-01-01

activity homogeneously distributed throughout the tissue substitute material. Many different sources can be used with a single lung set. The coefficients of variation for selected (i.e., those that had three or more values) counting efficiency data at different photon energies show that agreement between lung sets depends on the photon energy. In general, the lower the photon energy the worse the agreement. The 17.7 and 26.4 keV photopeaks show the highest coefficients of variation. This could be due to several factors: the distribution of the radionuclide in the lung insert, the positioning of the detector, the analysis of the photo peak. Once the photon energy rises above 60 keV the coefficient of variation is always less than 6%. This means that 95% of the time one can expect counting efficiencies derived from lung sets that have the activity homogeneously distributed through the tissue substitute material to be within 12% of each other. However, at lower photon energies the agreement is only to within 30%, and this may present a problem for lung intercomparison programs that use low energy emitting photons. (author)

Anatomic variation of cranial parasympathetic ganglia

Directory of Open Access Journals (Sweden)

Selma Siéssere

2008-06-01

Full Text Available Having broad knowledge of anatomy is essential for practicing dentistry. Certain anatomical structures call for detailed studies due to their anatomical and functional importance. Nevertheless, some structures are difficult to visualize and identify due to their small volume and complicated access. Such is the case of the parasympathetic ganglia located in the cranial part of the autonomic nervous system, which include: the ciliary ganglion (located deeply in the orbit, laterally to the optic nerve, the pterygopalatine ganglion (located in the pterygopalatine fossa, the submandibular ganglion (located laterally to the hyoglossus muscle, below the lingual nerve, and the otic ganglion (located medially to the mandibular nerve, right beneath the oval foramen. The aim of this study was to present these structures in dissected anatomic specimens and perform a comparative analysis regarding location and morphology. The proximity of the ganglia and associated nerves were also analyzed, as well as the number and volume of fibers connected to them. Human heads were dissected by planes, partially removing the adjacent structures to the point we could reach the parasympathetic ganglia. With this study, we concluded that there was no significant variation regarding the location of the studied ganglia. Morphologically, our observations concur with previous classical descriptions of the parasympathetic ganglia, but we observed variations regarding the proximity of the otic ganglion to the mandibular nerve. We also observed that there were variations regarding the number and volume of fiber bundles connected to the submandibular, otic, and pterygopalatine ganglia.

The use of anomalous scattering of uranium for the determination of biological macromolecules structures - From hard to soft X-rays

International Nuclear Information System (INIS)

Chesne-Seck, M.L.

2002-01-01

In order to solve biological macromolecules structures, structure factor phases must be derived from the intensities diffracted by the crystal. The SAD and the MAD methods make use of variations in scattering factors measured at specific absorption edges of heavy atoms, bound to the protein. The phasing power depends on the occupancy of the binding sites and on the variations of the scattering factors at the absorption edge that is used. With uranyl, numerous sites with low occupancies are usually obtained. We used new colored uranyl complexes, which give higher occupancies, to solve de novo the lysozyme structure and an unknown structure. We have developed the use of the My absorption edge of uranium (λ = 3,5 Angstroms), where a variation of 120 electrons is observed in the scattering factors. With a helium atmosphere to limit the X-rays absorption, we have collected three data sets, on a single image. Data were processed both with 'classical' and specific programs. (author) [fr

A novel pressure variation study on electronic structure, mechanical stability and thermodynamic properties of potassium based fluoroperovskite

Science.gov (United States)

Erum, Nazia; Azhar Iqbal, Muhammad

2017-09-01

The effect of pressure variation on stability, structural parameters, elastic constants, mechanical, electronic and thermodynamic properties of cubic SrKF3 fluoroperovskite have been investigated by using the full-potential linearized augmented plane wave (FP-LAPW) method combined with Quasi-harmonic Debye model in which the phonon effects are considered. The calculated lattice parameters show a prominent decrease in lattice constant and bonds length with the increase in pressure. The application of pressure from 0 to 25 GPa reveals a predominant characteristic associated with widening of bandgap with GGA and GGA plus Tran-Blaha modified Becke-Johnson (TB-mBJ) potential. The influence of pressure on elastic constants and their related mechanical parameters have been discussed in detail. Apart of linear dependence of elastic coefficients, transition from brittle to ductile behavior is also observed at elevated pressure ranges. We have successfully computed variation of lattice constant, volume expansion, bulk modulus, Debye temperature and specific heat capacities at pressure and temperature in the range of 0-25 GPa and 0-600 K.

Two Clock Transitions in Neutral Yb for the Highest Sensitivity to Variations of the Fine-Structure Constant

Science.gov (United States)

Safronova, Marianna S.; Porsev, Sergey G.; Sanner, Christian; Ye, Jun

2018-04-01

We propose a new frequency standard based on a 4 f146 s 6 p P0 3 -4 f136 s25 d (J =2 ) transition in neutral Yb. This transition has a potential for high stability and accuracy and the advantage of the highest sensitivity among atomic clocks to variation of the fine-structure constant α . We find its dimensionless α -variation enhancement factor to be K =-15 , in comparison to the most sensitive current clock (Yb+ E 3 , K =-6 ), and it is 18 times larger than in any neutral-atomic clocks (Hg, K =0.8 ). Combined with the unprecedented stability of an optical lattice clock for neutral atoms, this high sensitivity opens new perspectives for searches for ultralight dark matter and for tests of theories beyond the standard model of elementary particles. Moreover, together with the well-established 1S0-3P0 transition, one will have two clock transitions operating in neutral Yb, whose interleaved interrogations may further reduce systematic uncertainties of such clock-comparison experiments.

Joint Clustering and Component Analysis of Correspondenceless Point Sets: Application to Cardiac Statistical Modeling.

Science.gov (United States)

Gooya, Ali; Lekadir, Karim; Alba, Xenia; Swift, Andrew J; Wild, Jim M; Frangi, Alejandro F

2015-01-01

Construction of Statistical Shape Models (SSMs) from arbitrary point sets is a challenging problem due to significant shape variation and lack of explicit point correspondence across the training data set. In medical imaging, point sets can generally represent different shape classes that span healthy and pathological exemplars. In such cases, the constructed SSM may not generalize well, largely because the probability density function (pdf) of the point sets deviates from the underlying assumption of Gaussian statistics. To this end, we propose a generative model for unsupervised learning of the pdf of point sets as a mixture of distinctive classes. A Variational Bayesian (VB) method is proposed for making joint inferences on the labels of point sets, and the principal modes of variations in each cluster. The method provides a flexible framework to handle point sets with no explicit point-to-point correspondences. We also show that by maximizing the marginalized likelihood of the model, the optimal number of clusters of point sets can be determined. We illustrate this work in the context of understanding the anatomical phenotype of the left and right ventricles in heart. To this end, we use a database containing hearts of healthy subjects, patients with Pulmonary Hypertension (PH), and patients with Hypertrophic Cardiomyopathy (HCM). We demonstrate that our method can outperform traditional PCA in both generalization and specificity measures.

[Chromosomal variation in Chironomus plumosus L. (Diptera, Chironomidae) from populations of Bryansk region, Saratov region (Russia), and Gomel region (Belarus)].

Science.gov (United States)

Belyanina, S I

2015-02-01

Cytogenetic analysis was performed on samples of Chironomus plumosus L. (Diptera, Chironomidae) taken from waterbodies of various types in Bryansk region (Russia) and Gomel region (Belarus). Karyotypes of specimens taken from stream pools of the Volga were used as reference samples. The populations of Bryansk and Gomel regions (except for a population of Lake Strativa in Starodubskii district, Bryansk region) exhibit broad structural variation, including somatic mosaicism for morphotypes of the salivary gland chromosome set, decondensation of telomeric sites, and the presence of small structural changes, as opposed to populations of Saratov region. As compared with Saratov and Bryansk regions, the Balbiani ring in the B-arm of chromosome I is repressed in populations of Gomel region. It is concluded that the chromosome set of Ch. plumosus in a range of waterbodies of Bryansk and Gomel regions is unstable.

Transcriptome analysis of the sea cucumber (Apostichopus japonicus) with variation in individual growth.

Science.gov (United States)

Gao, Lei; He, Chongbo; Bao, Xiangbo; Tian, Meilin; Ma, Zhen

2017-01-01

The sea cucumber (Apostichopus japonicus) is an economically important aquaculture species in China. However, the serious individual growth variation often caused financial losses to farmers and the genetic mechanisms are poorly understood. In the present study, the extensively analysis at the transcriptome level for individual growth variation in sea cucumber was carried out. A total of 118946 unigenes were assembled from 255861 transcripts, with N50 of 1700. Of all unigenes, about 23% were identified with at least one significant match to known databases. In all four pair of comparison, 1840 genes were found to be expressed differently. Global hypometabolism was found to be occurred in the slow growing population, based on which the hypothesis was raised that growth retardation in individual growth variation of sea cucumber is one type of dormancy which is used to be against to adverse circumstances. Besides, the pathways such as ECM-receptor interaction and focal adhesion were enriched in the maintenance of cell and tissue structure and communication. Further, 76645 SSRs, 765242 SNPs and 146886 ins-dels were detected in the current study providing an extensive set of data for future studies of genetic mapping and selective breeding. In summary, these results will provides deep insight into the molecular basis of individual growth variation in marine invertebrates, and be valuable for understanding the physiological differences of growth process.

Transcriptome analysis of the sea cucumber (Apostichopus japonicus with variation in individual growth.

Directory of Open Access Journals (Sweden)

Lei Gao

Full Text Available The sea cucumber (Apostichopus japonicus is an economically important aquaculture species in China. However, the serious individual growth variation often caused financial losses to farmers and the genetic mechanisms are poorly understood. In the present study, the extensively analysis at the transcriptome level for individual growth variation in sea cucumber was carried out. A total of 118946 unigenes were assembled from 255861 transcripts, with N50 of 1700. Of all unigenes, about 23% were identified with at least one significant match to known databases. In all four pair of comparison, 1840 genes were found to be expressed differently. Global hypometabolism was found to be occurred in the slow growing population, based on which the hypothesis was raised that growth retardation in individual growth variation of sea cucumber is one type of dormancy which is used to be against to adverse circumstances. Besides, the pathways such as ECM-receptor interaction and focal adhesion were enriched in the maintenance of cell and tissue structure and communication. Further, 76645 SSRs, 765242 SNPs and 146886 ins-dels were detected in the current study providing an extensive set of data for future studies of genetic mapping and selective breeding. In summary, these results will provides deep insight into the molecular basis of individual growth variation in marine invertebrates, and be valuable for understanding the physiological differences of growth process.

Development of NIR calibration models to assess year-to-year variation in total non-structural carbohydrates in grasses using PLSR

DEFF Research Database (Denmark)

Shetty, Nisha; Gislum, René; Jensen, Anne Mette Dahl

2012-01-01

Near-infrared (NIR) spectroscopy was used in combination with chemometrics to quantify total nonstructural carbohydrates (TNC) in grass samples in order to overcome year-to-year variation. A total of 1103 above-ground plant and root samples were collected from different field and pot experiments...... and with various experimental designs in the period from 2001 to 2005. A calibration model was developed using partial least squares regression (PLSR). The calibration model on a large data set spanning five years demonstrated that quantification of TNC using NIR spectroscopy was possible with an acceptable low...

Variation in the oxytocin receptor gene (OXTR) is associated with differences in moral judgment.

Science.gov (United States)

Bernhard, Regan M; Chaponis, Jonathan; Siburian, Richie; Gallagher, Patience; Ransohoff, Katherine; Wikler, Daniel; Perlis, Roy H; Greene, Joshua D

2016-12-01

Moral judgments are produced through the coordinated interaction of multiple neural systems, each of which relies on a characteristic set of neurotransmitters. Genes that produce or regulate these neurotransmitters may have distinctive influences on moral judgment. Two studies examined potential genetic influences on moral judgment using dilemmas that reliably elicit competing automatic and controlled responses, generated by dissociable neural systems. Study 1 (N = 228) examined 49 common variants (SNPs) within 10 candidate genes and identified a nominal association between a polymorphism (rs237889) of the oxytocin receptor gene (OXTR) and variation in deontological vs utilitarian moral judgment (that is, judgments favoring individual rights vs the greater good). An association was likewise observed for rs1042615 of the arginine vasopressin receptor gene (AVPR1A). Study 2 (N = 322) aimed to replicate these findings using the aforementioned dilemmas as well as a new set of structurally similar medical dilemmas. Study 2 failed to replicate the association with AVPR1A, but replicated the OXTR finding using both the original and new dilemmas. Together, these findings suggest that moral judgment is influenced by variation in the oxytocin receptor gene and, more generally, that single genetic polymorphisms can have a detectable effect on complex decision processes. © The Author (2016). Published by Oxford University Press.

The band gap variation of a two dimensional binary locally resonant structure in thermal environment

Directory of Open Access Journals (Sweden)

Zhen Li

2017-01-01

Full Text Available In this study, the numerical investigation of thermal effect on band gap dynamical characteristic for a two-dimensional binary structure composed of aluminum plate periodically filled with nitrile rubber cylinder is presented. Initially, the band gap of the binary structure variation trend with increasing temperature is studied by taking the softening effect of thermal stress into account. A breakthrough is made which found the band gap being narrower and shifting to lower frequency in thermal environment. The complete band gap which in higher frequency is more sensitive to temperature that it disappears with temperature increasing. Then some new transformed models are created by changing the height of nitrile rubber cylinder from 1mm to 7mm. Simulations show that transformed model can produce a wider band gap (either flexure or complete band gap. A proper forbidden gap of elastic wave can be utilized in thermal environment although both flexure and complete band gaps become narrower with temperature. Besides that, there is a zero-frequency flat band appearing in the first flexure band, and it becomes broader with temperature increasing. The band gap width decreases trend in thermal environment, as well as the wider band gap induced by the transformed model with higher nitrile rubber cylinder is useful for the design and application of phononic crystal structures in thermal environment.

Slope variation and population structure of tree species from different ecological groups in South Brazil.

Science.gov (United States)

Bianchini, Edmilson; Garcia, Cristina C; Pimenta, José A; Torezan, José M D

2010-09-01

Size structure and spatial arrangement of 13 abundant tree species were determined in a riparian forest fragment in Paraná State, South Brazil (23°16'S and 51°01'W). The studied species were Aspidosperma polyneuron Müll. Arg., Astronium graveolens Jacq. and Gallesia integrifolia (Spreng) Harms (emergent species); Alseis floribunda Schott, Ruprechtia laxiflora Meisn. and Bougainvillea spectabilis Willd. (shade-intolerant canopy species); Machaerium paraguariense Hassl, Myroxylum peruiferum L. and Chrysophyllum gonocarpum (Mart. & Eichler ex Miq.) Engl. (shade-tolerant canopy species); Sorocea bonplandii (Baill.) Bürger, Trichilia casaretti C. Dc, Trichilia catigua A. Juss. and Actinostemon concolor (Spreng.) Müll. Arg. (understory small trees species). Height and diameter structures and basal area of species were analyzed. Spatial patterns and slope correlation were analyzed by Moran's / spatial autocorrelation coefficient and partial Mantel test, respectively. The emergent and small understory species showed the highest and the lowest variations in height, diameter and basal area. Size distribution differed among emergent species and also among canopy shade-intolerant species. The spatial pattern ranged among species in all groups, except in understory small tree species. The slope was correlated with spatial pattern for A. polyneuron, A. graveolens, A. floribunda, R. laxiflora, M. peruiferum and T. casaretti. The results indicated that most species occurred in specific places, suggesting that niche differentiation can be an important factor in structuring the tree community.

Use of Lanczos vectors in fluid/structure interaction problems

International Nuclear Information System (INIS)

Jeans, R.; Mathews, I.C.

1992-01-01

The goals of any numerical computational technique used for the solution of structural acoustics problems in the exterior infinite domain should be of accuracy with rapid convergence, robustness, and computational efficiency. A computer program has been developed to achieve each of these three goals. Accuracy and robustness in the numerical representation of the integral equations used to represent the infinite fluid was attained through the use of boundary element implementations of the surface Helmholtz integral equations. The computational efficiency was resolved through the use of Lanczos vectors to model the deformation characteristics of the structure. The authors have developed collocation and variational techniques to overcome the difficulties previously encountered in the numerical implementation of the hypersingular integral operator. The Cauchy singularity present in the integral formulation is made numerically amenable through the use of tangential derivatives in both the collocation and variational techniques. The variational approach has the advantage that the resulting added fluid mass term is symmetric and combines efficiently with a finite element approximation of the structural elastic response. Several different strategies making use of the Lanczos vectors have been investigated. The first involved the use of Lanczos vectors solely to characterize the structural response. This reduced form of the structural dynamical matrix was then substituted back into a Burton and Miller formulation of the acoustic problem. The second strategy investigated involved forming the complex Lanzcos vectors of the dynamical matrix formed from the addition of a symmetrical added fluid matrix to the structural mass matrix. The size of resultant matrix equation set solved at each frequency for this strategy is determined by the number of Lanczos vectors used. 19 refs., 10 figs., 2 tabs

Beyond main effects of gene-sets: harsh parenting moderates the association between a dopamine gene-set and child externalizing behavior

NARCIS (Netherlands)

J. Windhorst (Judith); V. Mileva-Seitz (Viara); R.C.A. Rippe (Ralph C.A.); H.W. Tiemeier (Henning); V.W.V. Jaddoe (Vincent); F.C. Verhulst (Frank); M.H. van IJzendoorn (Rien); M.J. Bakermans-Kranenburg (Marian)

2016-01-01

textabstractBackground: In a longitudinal cohort study, we investigated the interplay of harsh parenting and genetic variation across a set of functionally related dopamine genes, in association with children's externalizing behavior. This is one of the first studies to employ gene-based and

Generalized structural theory of freezing

International Nuclear Information System (INIS)

Yussouff, M.

1980-10-01

The first-principles order parameter theory of freezing, proposed in an earlier work, has been successful in yielding quantitative agreement with known freezing parameters for monoatomic liquids forming solids with one atom per unit cell. A generalization of this theory is presented here to include the effects of a basis set of many atoms per unit cell. The basic equations get modified by the 'density structure factors' fsub(i) which arise from the density variations within the unit cell. Calculations are presented for the important case of monoatomic liquids freezing into hexagonal close packed solids. It is concluded that all freezing transitions can be described by using structural correlations in the liquid instead of the pair potential; and that the three body correlations are important in deciding the type of solid formed after freezing. (author)

Day-to-day and within-day variation in urinary iodine excretion

DEFF Research Database (Denmark)

Rasmussen, Lone Banke; Ovesen, L.; Christiansen, E.

1999-01-01

Objective: To examine the day-to-day and within-day variation in urinary iodine excretion and the day-to-day variation in iodine intake. Design: Collection of consecutive 24-h urine samples and casual urine samples over 24 h. Setting: The study population consisted of highly motivated subjects fr...

Structural variation of alpha-synuclein with temperature by a coarse-grained approach with knowledge-based interactions

Directory of Open Access Journals (Sweden)

Peter Mirau

2015-09-01

Full Text Available Despite enormous efforts, our understanding the structure and dynamics of α-synuclein (ASN, a disordered protein (that plays a key role in neurodegenerative disease is far from complete. In order to better understand sequence-structure-property relationships in α-SYNUCLEIN we have developed a coarse-grained model using knowledge-based residue-residue interactions and used it to study the structure of free ASN as a function of temperature (T with a large-scale Monte Carlo simulation. Snapshots of the simulation and contour contact maps show changes in structure formation due to self-assembly as a function of temperature. Variations in the residue mobility profiles reveal clear distinction among three segments along the protein sequence. The N-terminal (1-60 and C-terminal (96-140 regions contain the least mobile residues, which are separated by the higher mobility non-amyloid component (NAC (61-95. Our analysis of the intra-protein contact profile shows a higher frequency of residue aggregation (clumping in the N-terminal region relative to that in the C-terminal region, with little or no aggregation in the NAC region. The radius of gyration (Rg of ASN decays monotonically with decreasing the temperature, consistent with the finding of Allison et al. (JACS, 2009. Our analysis of the structure function provides an insight into the mass (N distribution of ASN, and the dimensionality (D of the structure as a function of temperature. We find that the globular structure with D ≈ 3 at low T, a random coil, D ≈ 2 at high T and in between (2 ≤ D ≤ 3 at the intermediate temperatures. The magnitudes of D are in agreement with experimental estimates (J. Biological Chem 2002.

Setting goals in psychotherapy

DEFF Research Database (Denmark)

Emiliussen, Jakob; Wagoner, Brady

2013-01-01

The present study is concerned with the ethical dilemmas of setting goals in therapy. The main questions that it aims to answer are: who is to set the goals for therapy and who is to decide when they have been reached? The study is based on four semi-­‐structured, phenomenological interviews...

Spatio-temporal structure and cycle to cycle variations of an in-cylinder tumbling flow

Science.gov (United States)

Voisine, M.; Thomas, L.; Borée, J.; Rey, P.

2011-05-01

The aim of this paper is to make use of PIV and high-speed PIV in a research engine of moderate tumbling ratio in order to analyze both the spatial structure of the flow and its temporal evolution during series of consecutive cycles. Appropriate analyzing tools are introduced, and four different points are addressed: (1) the chain of events driving the generation of the three-dimensional mean tumbling motion is investigated; (2) a Lagrangian analysis of the roll-up of the tumbling jet in individual cycles demonstrates a strong cycle to cycle variation during the compression phase (the rms of the position of the jet front being approximately 10% of the piston stroke); (3) focussing on the "breakdown" phase, phase invariant proper orthogonal decomposition enables us to distinguish cycles according to their structure near top dead center (TDC). We show that when the coherent energy of the flow is conserved, there is no increase in the fluctuating kinetic energy; (4) finally, the phase-averaged Reynolds stresses is decomposed into a contribution of the in-cycle coherence and the turbulence carried by the flow states. Approximately 30% of the fluctuating kinetic energy is due to cycle to cycle fluctuations in this chamber near TDC.

About efficient quasi-Newtonian schemes for variational calculations in nuclear structure

International Nuclear Information System (INIS)

Puddu, G.

2009-01-01