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Sample records for apply local clustering

  1. Clustering by Local Gravitation.

    PubMed

    Wang, Zhiqiang; Yu, Zhiwen; Chen, C L Philip; You, Jane; Gu, Tianlong; Wong, Hau-San; Zhang, Jun

    2017-05-02

    The objective of cluster analysis is to partition a set of data points into several groups based on a suitable distance measure. We first propose a model called local gravitation among data points. In this model, each data point is viewed as an object with mass, and associated with a local resultant force (LRF) generated by its neighbors. The motivation of this paper is that there exist distinct differences between the LRFs (including magnitudes and directions) of the data points close to the cluster centers and at the boundary of the clusters. To capture these differences efficiently, two new local measures named centrality and coordination are further investigated. Based on empirical observations, two new clustering methods called local gravitation clustering and communication with local agents are designed, and several test cases are conducted to verify their effectiveness. The experiments on synthetic data sets and real-world data sets indicate that both clustering approaches achieve good performance on most of the data sets.

  2. Population structure with localized haplotype clusters.

    PubMed

    Browning, Sharon R; Weir, Bruce S

    2010-08-01

    We propose a multilocus version of F(ST) and a measure of haplotype diversity using localized haplotype clusters. Specifically, we use haplotype clusters identified with BEAGLE, which is a program implementing a hidden Markov model for localized haplotype clustering and performing several functions including inference of haplotype phase. We apply this methodology to HapMap phase 3 data. With this haplotype-cluster approach, African populations have highest diversity and lowest divergence from the ancestral population, East Asian populations have lowest diversity and highest divergence, and other populations (European, Indian, and Mexican) have intermediate levels of diversity and divergence. These relationships accord with expectation based on other studies and accepted models of human history. In contrast, the population-specific F(ST) estimates obtained directly from single-nucleotide polymorphisms (SNPs) do not reflect such expected relationships. We show that ascertainment bias of SNPs has less impact on the proposed haplotype-cluster-based F(ST) than on the SNP-based version, which provides a potential explanation for these results. Thus, these new measures of F(ST) and haplotype-cluster diversity provide an important new tool for population genetic analysis of high-density SNP data.

  3. Cluster analysis applied to multiparameter geophysical dataset

    NASA Astrophysics Data System (ADS)

    Di Giuseppe, M. G.; Troiano, A.; Troise, C.; De Natale, G.

    2012-04-01

    Multi-parameter acquisition is a common geophysical field practice nowadays. Regularly seismic velocity and attenuation, gravity and electromagnetic dataset are acquired in a certain area, to obtain a complete characterization of the some investigate feature of the subsoil. Such a richness of information is often underestimated, although an integration of the analysis could provide a notable improving in the imaging of the investigated structures, mostly because the handling of distinct parameters and their joint inversion still presents several and severe problems. Post-inversion statistical techniques represent a promising approach to these questions, providing a quick, simple and elegant way to obtain this advantageous but complex integration. We present an approach based on the partition of the analyzed multi parameter dataset in a number of different classes, identified as localized regions of high correlation. These classes, or 'Cluster', are structured in such a way that the observations pertaining to a certain group are more similar to each other than the observations belonging to a different one, according to an optimal logical criterion. Regions of the subsoil sharing the same physical characteristic are so identified, without a-priori or empirical relationship linking the distinct measured parameters. The retrieved imaging results highly affordable in a statistical sense, specifically due to this lack of external hypothesis that are, instead, indispensable in a full joint inversion, were works, as matter of fact, just a real constrain for the inversion process, not seldom of relative consistence. We apply our procedure to a certain number of experimental dataset, related to several structures at very different scales presents in the Campanian district (southern Italy). These structures goes from the shallows evidence of the active fault zone originating the M 7.9 Irpinia earthquake to the main feature characterizing the Campi Flegrei Caldera and the Mt

  4. Applying fuzzy clustering optimization algorithm to extracting traffic spatial pattern

    NASA Astrophysics Data System (ADS)

    Hu, Chunchun; Shi, Wenzhong; Meng, Lingkui; Liu, Min

    2009-10-01

    Traditional analytical methods for traffic information can't meet to need of intelligent traffic system. Mining value-add information can deal with more traffic problems. The paper exploits a new clustering optimization algorithm to extract useful spatial clustered pattern for predicting long-term traffic flow from macroscopic view. Considering the sensitivity of initial parameters and easy falling into local extreme in FCM algorithm, the new algorithm applies Particle Swarm Optimization method, which can discovery the globe optimal result, to the FCM algorithm. And the algorithm exploits the union of the clustering validity index and objective function of the FCM algorithm as the fitness function of the PSO algorithm. The experimental result indicates that it is effective and efficient. For fuzzy clustering of road traffic data, it can produce useful spatial clustered pattern. And the clustered centers represent the locations which have heavy traffic flow. Moreover, the parameters of the patterns can provide intelligent traffic system with assistant decision support.

  5. A local search for a graph clustering problem

    NASA Astrophysics Data System (ADS)

    Navrotskaya, Anna; Il'ev, Victor

    2016-10-01

    In the clustering problems one has to partition a given set of objects (a data set) into some subsets (called clusters) taking into consideration only similarity of the objects. One of most visual formalizations of clustering is graph clustering, that is grouping the vertices of a graph into clusters taking into consideration the edge structure of the graph whose vertices are objects and edges represent similarities between the objects. In the graph k-clustering problem the number of clusters does not exceed k and the goal is to minimize the number of edges between clusters and the number of missing edges within clusters. This problem is NP-hard for any k ≥ 2. We propose a polynomial time (2k-1)-approximation algorithm for graph k-clustering. Then we apply a local search procedure to the feasible solution found by this algorithm and hold experimental research of obtained heuristics.

  6. Applying Machine Learning to Star Cluster Classification

    NASA Astrophysics Data System (ADS)

    Fedorenko, Kristina; Grasha, Kathryn; Calzetti, Daniela; Mahadevan, Sridhar

    2016-01-01

    Catalogs describing populations of star clusters are essential in investigating a range of important issues, from star formation to galaxy evolution. Star cluster catalogs are typically created in a two-step process: in the first step, a catalog of sources is automatically produced; in the second step, each of the extracted sources is visually inspected by 3-to-5 human classifiers and assigned a category. Classification by humans is labor-intensive and time consuming, thus it creates a bottleneck, and substantially slows down progress in star cluster research.We seek to automate the process of labeling star clusters (the second step) through applying supervised machine learning techniques. This will provide a fast, objective, and reproducible classification. Our data is HST (WFC3 and ACS) images of galaxies in the distance range of 3.5-12 Mpc, with a few thousand star clusters already classified by humans as a part of the LEGUS (Legacy ExtraGalactic UV Survey) project. The classification is based on 4 labels (Class 1 - symmetric, compact cluster; Class 2 - concentrated object with some degree of asymmetry; Class 3 - multiple peak system, diffuse; and Class 4 - spurious detection). We start by looking at basic machine learning methods such as decision trees. We then proceed to evaluate performance of more advanced techniques, focusing on convolutional neural networks and other Deep Learning methods. We analyze the results, and suggest several directions for further improvement.

  7. Localization and clustering in atomic nuclei

    NASA Astrophysics Data System (ADS)

    Ebran, J.-P.; Khan, E.; Nikšić, T.; Vretenar, D.

    2017-10-01

    Nucleon localization, and formation of clusters in nucleonic matter and finite nuclei are explored in a framework based on nuclear energy density functionals. The liquid-cluster transition is investigated and different measures of localization are discussed. The formation and evolution of α-clusters in excited states of both N = Z and neutron-rich nuclei are analysed. The effects of spin-orbit coupling are discussed in relation to the confining potential.

  8. Anderson Localization: Dynamical Cluster Approximation - Typical Medium Theory Perspective

    NASA Astrophysics Data System (ADS)

    Ekuma, Chinedu; Meng, Ziyang; Terletska, Hanna; Moreno, Juana; Jarrell, Mark; Dobrosavljevic, Vladimir

    2013-03-01

    Mean field theories like the coherent potential approximation (CPA) and its cluster extensions, including the dynamical cluster approximation (DCA), fail to describe the Anderson localization transition in disordered systems. This failure is intrinsic to these theories as the algebraically averaged quantities used in them always favor the metallic state, and hence cannot describe the localization transition. Here we extend the Typical Medium Theory (TMT), which replaces the average quantities with their corresponding typical (geometrically averaged) equivalents, to its cluster form such that non-local correlations can be incorporated systematically. We apply our method to study the localization phenomena in various dimensions. Such an approach opens a new avenue to study localization effect both in model and in real materials. This work was supported by the National Science Foundation (NSF) [Award No. LA-SiGMA EPS-1003897, DMR-1005751], Department of Energy, DOE-CMCSN

  9. Locally adaptive bilateral clustering for universal image denoising

    NASA Astrophysics Data System (ADS)

    Toh, K. K. V.; Mat Isa, N. A.

    2012-12-01

    This paper presents a novel and efficient locally adaptive denoising method based on clustering of pixels into regions of similar geometric and radiometric structures. Clustering is performed by adaptively segmenting pixels in the local kernel based on their augmented variational series. Then, noise pixels are restored by selectively considering the radiometric and spatial properties of every pixel in the formed clusters. The proposed method is exceedingly robust in conveying reliable local structural information even in the presence of noise. As a result, the proposed method substantially outperforms other state-of-the-art methods in terms of image restoration and computational cost. We support our claims with ample simulated and real data experiments. The relatively fast runtime from extensive simulations also suggests that the proposed method is suitable for a variety of image-based products — either embedded in image capturing devices or applied as image enhancement software.

  10. Quality function deployment applied to local traffic accident reduction.

    PubMed

    Sohn, S Y

    1999-11-01

    One of the major tasks of police stations is the management of local road traffic accidents. Proper prevention policy which reflects the local accident characteristics could immensely help individual police stations in decreasing various severity levels of road traffic accidents. In order to relate accident variation to local driving environmental characteristics, we use both cluster analysis and Poisson regression. The fitted result at the level of each cluster for each type of accident severity is utilized as an input to quality function deployment. Quality function deployment (QFD) has been applied to customer satisfaction in various industrial quality improvement settings, where several types of customer requirements are related to various control factors. We show how QFD enables one to set priorities on various road accident control policies to which each police station has to pay particular attention.

  11. Localized Multiple Kernel Learning With Dynamical Clustering and Matrix Regularization.

    PubMed

    Han, Yina; Yang, Kunde; Yang, Yixin; Ma, Yuanliang

    2016-12-20

    Localized multiple kernel learning (LMKL) is an attractive strategy for combining multiple heterogeneous features with regard to their discriminative power for each individual sample. However, the learning of numerous local solutions may not scale well even for a moderately sized training set, and the independently learned local models may suffer from overfitting. Hence, in existing local methods, the distributed samples are typically assumed to share the same weights, and various unsupervised clustering methods are applied as preprocessing. In this paper, to enable the learner to discover and benefit from the underlying local coherence and diversity of the samples, we incorporate the clustering procedure into the canonical support vector machine-based LMKL framework. Then, to explore the relatedness among different samples, which has been ignored in a vector ℓp-norm analysis, we organize the cluster-specific kernel weights into a matrix and introduce a matrix-based extension of the ℓp-norm for constraint enforcement. By casting the joint optimization problem as a problem of alternating optimization, we show how the cluster structure is gradually revealed and how the matrix-regularized kernel weights are obtained. A theoretical analysis of such a regularizer is performed using a Rademacher complexity bound, and complementary empirical experiments on real-world data sets demonstrate the effectiveness of our technique.

  12. [Regional and local clusters of railway suicides].

    PubMed

    Erazo, N; Baumert, J; Ladwig, K-H

    2004-11-01

    Suicide research has identified regional and local clusters of increased suicide prevalence. As part of a comprehensive prevention strategy to fight railway suicides, we sought to identify such particular clusters on the German Railway net (total length 37,080 km) during a 6-year observation period (1997-2002). Data stem from the central registry of all person accidents on the German Railway net. During the observation period, a total of 5,731 suicides (in average 18 cases per week) were registered. Against expectation derived from distribution patterns in the general suicide research, we found a preponderance in the southern part compared to the northern part of Germany and a significant downward trend from west to east ( p=0.004). Most suicides occurred on open track (66%) compared to suicides at railway platforms (34%). We identified 16 places of high risk with 6 to 29 suicides per railway km. Of these high risk places, 75% were in the proximity of psychiatric hospitals. Increased awareness for regional and local suicide clusters, initiatives to reduce the accessibility and warning infra-red beams are among recommendations for suicide prevention derived from these data.

  13. SUPERDENSE MASSIVE GALAXIES IN WINGS LOCAL CLUSTERS

    SciTech Connect

    Valentinuzzi, T.; D'Onofrio, M.; Fritz, J.; Poggianti, B. M.; Bettoni, D.; Fasano, G.; Moretti, A.; Omizzolo, A.; Varela, J.; Cava, A.; Couch, W. J.; Dressler, A.; Moles, M.; Kjaergaard, P.; Vanzella, E.

    2010-03-20

    Massive quiescent galaxies at z > 1 have been found to have small physical sizes, and hence to be superdense. Several mechanisms, including minor mergers, have been proposed for increasing galaxy sizes from high- to low-z. We search for superdense massive galaxies in the WIde-field Nearby Galaxy-cluster Survey (WINGS) of X-ray selected galaxy clusters at 0.04 < z < 0.07. We discover a significant population of superdense massive galaxies with masses and sizes comparable to those observed at high redshift. They approximately represent 22% of all cluster galaxies more massive than 3 x 10{sup 10} M{sub sun}, are mostly S0 galaxies, have a median effective radius (R{sub e} ) = 1.61 +- 0.29 kpc, a median Sersic index (n) = 3.0 +- 0.6, and very old stellar populations with a median mass-weighted age of 12.1 +- 1.3 Gyr. We calculate a number density of 2.9 x 10{sup -2} Mpc{sup -3} for superdense galaxies in local clusters, and a hard lower limit of 1.3 x 10{sup -5} Mpc{sup -3} in the whole comoving volume between z = 0.04 and z = 0.07. We find a relation between mass, effective radius, and luminosity-weighted age in our cluster galaxies, which can mimic the claimed evolution of the radius with redshift, if not properly taken into account. We compare our data with spectroscopic high-z surveys and find that-when stellar masses are considered-there is consistency with the local WINGS galaxy sizes out to z {approx} 2, while a discrepancy of a factor of 3 exists with the only spectroscopic z > 2 study. In contrast, there is strong evidence for a large evolution in radius for the most massive galaxies with M{sub *} > 4 x 10{sup 11} M{sub sun} compared to similarly massive galaxies in WINGS, i.e., the brightest cluster galaxies.

  14. Analysis of forest fires spatial clustering using local fractal measure

    NASA Astrophysics Data System (ADS)

    Kanevski, Mikhail; Rochat, Mikael; Timonin, Vadim

    2013-04-01

    The research deals with an application of local fractal measure - local sandbox counting or mass counting, for the characterization of patterns of spatial clustering. The main application concerns the simulated (random patterns within validity domain in forest regions) and real data (forest fires in Ticino, Switzerland) case studies. The global patterns of spatial clustering of forest fires were extensively studied using different topological (nearest-neighbours, Voronoi polygons), statistical (Ripley's k-function, Morisita diagram) and fractal/multifractal measures (box-counting, sandbox counting, lacunarity) (Kanevski, 2008). Generalizations of these measures to functional ones can reveal the structure of the phenomena, e.g. burned areas. All these measures are valuable and complementary tools to study spatial clustering. Moreover, application of the validity domain (complex domain where phenomena is studied) concept helps in understanding and interpretation of the results. In the present paper a sandbox counting method was applied locally, i.e. each point of ignition was considered as a centre of events counting with an increasing search radius. Then, the local relationships between the radius and the number of ignition points within the given radius were examined. Finally, the results are mapped using an interpolation algorithm for the visualization and analytical purposes. Both 2d (X,Y) and 3d (X,Y,Z) cases were studied and compared. Local "fractal" study gives an interesting spatially distributed picture of clustering. The real data case study was compared with a reference homogeneous pattern - complete spatial randomness. The difference between two patterns clearly indicates the regions with important spatial clustering. An extension to the local functional measure was applied taking into account the surface of burned area, i.e. by analysing only data with the fires above some threshold of burned area. Such analysis is similar to marked point processes and

  15. Constrained spectral clustering under a local proximity structure assumption

    NASA Technical Reports Server (NTRS)

    Wagstaff, Kiri; Xu, Qianjun; des Jardins, Marie

    2005-01-01

    This work focuses on incorporating pairwise constraints into a spectral clustering algorithm. A new constrained spectral clustering method is proposed, as well as an active constraint acquisition technique and a heuristic for parameter selection. We demonstrate that our constrained spectral clustering method, CSC, works well when the data exhibits what we term local proximity structure.

  16. Business Clusters: Building on Local Strengths.

    ERIC Educational Resources Information Center

    Baldwin, Fred D.

    2001-01-01

    The Northwest Pennsylvania Industrial Resource Center's "wood cluster initiative" illustrates the benefits of rural business clusters. The initiative is turning a loose grouping of timber and forest-product firms into a competitive system by providing technical assistance, helping businesses plan and conduct job training programs,…

  17. Applied study of optical interconnection link in computer cluster

    NASA Astrophysics Data System (ADS)

    Zhou, Ge; Tian, Jindong; Zhang, Nan; Jing, Wencai; Li, Haifeng

    2000-10-01

    In this paper, some study results to apply fiber link to a computer cluster are presented. The research is based on a ring network topology for a cluster system, which is connected by gigabit/s virtual parallel optical fiber link (VPOFLink) and its driver is for Linux Operating System, the transmission protocol of VPOFLink is compliant with Ethernet standard. We have studied the effect of different types of motherboard on transmission rate of the VPOFLink, and have analyzed the influence of optical interconnection network topology and computer networks protocol on the performance of this optical interconnection computer cluster. The round-trip transmission bandwidth of the VPOFLink have been tested, and the factors that limit transmission bandwidth, such as modes of forwarding data packets in the optical interconnection ring networks, and the size of the link buffer etc., are investigated.

  18. Adapted G-mode Clustering Method applied to Asteroid Taxonomy

    NASA Astrophysics Data System (ADS)

    Hasselmann, Pedro H.; Carvano, Jorge M.; Lazzaro, D.

    2013-11-01

    The original G-mode was a clustering method developed by A. I. Gavrishin in the late 60's for geochemical classification of rocks, but was also applied to asteroid photometry, cosmic rays, lunar sample and planetary science spectroscopy data. In this work, we used an adapted version to classify the asteroid photometry from SDSS Moving Objects Catalog. The method works by identifying normal distributions in a multidimensional space of variables. The identification starts by locating a set of points with smallest mutual distance in the sample, which is a problem when data is not planar. Here we present a modified version of the G-mode algorithm, which was previously written in FORTRAN 77, in Python 2.7 and using NumPy, SciPy and Matplotlib packages. The NumPy was used for array and matrix manipulation and Matplotlib for plot control. The Scipy had a import role in speeding up G-mode, Scipy.spatial.distance.mahalanobis was chosen as distance estimator and Numpy.histogramdd was applied to find the initial seeds from which clusters are going to evolve. Scipy was also used to quickly produce dendrograms showing the distances among clusters. Finally, results for Asteroids Taxonomy and tests for different sample sizes and implementations are presented.

  19. Segmentation-based clustering of hyperspectral images using local band selection

    NASA Astrophysics Data System (ADS)

    Mehta, Anand; Dikshit, Onkar

    2017-01-01

    This study addresses the problems associated with high dimensionality of hyperspectral images in reference to clustering. A new local band selection approach that takes both relevancy and redundancy among the bands into account while obtaining the multiple relevant set of bands is developed. The local band selection approach is then incorporated within a multistage clustering framework that includes three stages: segmentation, region merging, and projected clustering. At first, k-means is used to produce initial segments/regions. Then, in the region merging stage, the modified local mutually best region merging strategy is applied on the initial segments to produce the refined segmentation map. Finally, an improved projected clustering technique is used to group these segments into a fixed number of clusters. Further, the main principle of projected clustering, that different sets of point may cluster better for different subsets of dimensions, is extended to region merging by incorporating the suggested local band selection approach. The framework requires input for two major parameters, which are number of clusters (k) and number of relevant bands (l). The framework is tested over two hyperspectral images and compared with other clustering frameworks. The experimental results confirm the effectiveness of the proposed framework.

  20. Local control theory applied to molecular photoassociation.

    PubMed

    Marquetand, Philipp; Engel, Volker

    2007-08-28

    Local control theory (LCT) is employed to achieve molecular photoassociation with shaped laser pulses. Within LCT, the control fields are constructed from the response of the system to the perturbation which makes them accessible to a straightforward interpretation. This is shown regarding the ground-state collision of H+F and H+I atoms. Different objectives are defined, which aim at the formation of vibrational cold or hot associated molecules, respectively. Results are presented for s-wave scattering, where the rotational degree of freedom is ignored and also for full scale calculations including rotations, in order to describe more realistic conditions.

  1. Clustered and distinct: a taxonomy of local multihospital systems.

    PubMed

    Shay, Patrick D; Mick, Stephen S Farnsworth

    2016-01-16

    Despite their prevalence and power in markets throughout the United States, local multihospital systems (LMSs)-also referred to as hospital-based "clusters"-remain an understudied organizational form, with studies instead primarily focusing either upon individual hospitals or viewing hospital systems collectively without distinguishing the local "sub-systems" that comprise larger regional or national hospital chains. To better understand these organizational forms, we develop a taxonomy specifically devoted to LMSs, applying taxonomic analysis methods to a sample of LMSs in six U.S. states while accounting for LMSs' geographic arrangements and non-hospital-based service locations. Our analysis identifies five distinct LMS categories, with forms clearly distinguished according to their varying degrees of differentiation and integration. The study's results accentuate the importance of accounting for hospital systems' activities and arrangements in local markets-including their non-hospital-based sites-and highlight differences in systems' achievement of integration and coordination across services and locations, providing considerations in light of U.S. health system reform as well as international patterns of regional system formation.

  2. Grey relational clustering associated with CAPRI applied to FPGA placement

    NASA Astrophysics Data System (ADS)

    Wu, Jan-Ou; Fan, Yang-Hsin; Wang, San-Fu

    2016-04-01

    Grey relational clustering is used to minimise wire length during field programmable gate arrays (FPGA) placement and routing. The proposed Grey Relational Clustering Apply to Placement (GRAP) algorithm combines grey relational clustering and convex assigned placement for regular ICs method to construct a placement netlist, which was successfully used to solve the problem of minimising wire length in an FPGA placement. Upon calculating the grey relational grade, GRAP can rank the sequence and analyse the minimal distance in configuration logic blocks based on the grey relational sequence and combined connection-based approaches. The experimental results demonstrate that the GRAP effectively compares the Hibert, Z and Snake with bounding box (BB) cost function in the space-filling curve. The GRAP improved BB cost by 0.753%, 0.324% and 0.096% for the Hilbert, Z and Snake, respectively. This study also compares the critical path with the space-filling curve. The GRAP approach improved the critical path for Snake by 1.3% in the space-filling curve; however, the GRAP increased critical path wire by 1.38% and 0.03% over that of the Hilbert and Z of space-filling curve, respectively.

  3. Jammed Clusters and Non-locality in Dense Granular Flows

    NASA Astrophysics Data System (ADS)

    Kharel, Prashidha; Rognon, Pierre

    We investigate the micro-mechanisms underpinning dense granular flow behaviour from a series of DEM simulations of pure shear flows of dry grains. We observe the development of transient clusters of jammed particles within the flow. Typical size of such clusters is found to scale with the inertial number with a power law that is similar to the scaling of shear-rate profile relaxation lengths observed previously. Based on the simple argument that transient clusters of size l exist in the dense flow regime, the formulation of steady state condition for non-homogeneous shear flow results in a general non-local relation, which is similar in form to the non-local relation conjectured for soft glassy flows. These findings suggest the formation of jammed clusters to be the key micro-mechanism underpinning non-local behaviour in dense granular flows. Particles and Grains Laboratory, School of Civil Engineering, The University of Sydney, Sydney, NSW 2006, Australia.

  4. The creation of local clusters in arbitrarily given grids

    NASA Technical Reports Server (NTRS)

    Eiseman, Peter R.

    1986-01-01

    A method is presented to smoothly insert pointwise clusters into any given grid regardless of its origin, its topology, or its dimensionality. The process amounts to a local movement of the given coordinate curves or surfaces to more highly resolve an object. The object about which clustering is created can be a point, a curve, a surface, or segments of a curve or surface. The basic clustering capability is established by forming a grid operator for a single cluster. With a view toward multiple clusters being created about various objects, the basic operator is seen as an elementary operator. An algorithm is presented to execute the general elementary operation in three dimensions. In FORTRAN, this assumes the form of a subroutine which is fully operational and is presented to serve as a basic model for any such elementary clustering operation.

  5. Local Turgor Pressure Reduction via Channel Clustering.

    PubMed

    Scher-Zagier, Jonah K; Carlsson, Anders E

    2016-12-20

    The primary drivers of yeast endocytosis are actin polymerization and curvature-generating proteins, such as clathrin and BAR domain proteins. Previous work has indicated that these factors may not be capable of generating the forces necessary to overcome turgor pressure. Thus local reduction of the turgor pressure, via localized accumulation or activation of solute channels, might facilitate endocytosis. The possible reduction in turgor pressure was calculated numerically, by solving the diffusion equation through a Legendre polynomial expansion. It was found that for a region of increased permeability having radius 45 nm, as few as 60 channels with a spacing of 10 nm could locally decrease the turgor pressure by 50%. We identified a key dimensionless parameter, p = P1a/D, where P1 is the increased permeability, a is the radius of the permeable region, and D is the solute diffusion coefficient. When p > 0.44, the turgor pressure is locally reduced by >50%. An approximate analytic theory was used to generate explicit formulas for the turgor pressure reduction in terms of key parameters. These findings may also be relevant to plants, where the mechanisms that allow endocytosis to proceed despite high turgor pressure are largely unknown. Copyright © 2016 Biophysical Society. Published by Elsevier Inc. All rights reserved.

  6. Nearest hyperplane distance neighbor clustering algorithm applied to gene co-expression analysis in Alzheimer's disease.

    PubMed

    Pasluosta, Cristian F; Dua, Prerna; Lukiw, Walter J

    2011-01-01

    Microarray analysis can contribute considerably to the understanding of biologically significant cellular mechanisms that yield novel information regarding co-regulated sets of gene patterns. Clustering is one of the most popular tools for analyzing DNA microarray data. In this paper, we present an unsupervised clustering algorithm based on the K-local hyperplane distance nearest-neighbor classifier (HKNN). We adapted the well-known nearest neighbor clustering algorithm for use with hyperplane distance. The result is a simple and computationally inexpensive unsupervised clustering algorithm that can be applied to high-dimensional data. It has been reported that the NFkB1 gene is progressively over-expressed in moderate-to-severe Alzheimer's disease (AD) cases, and that the NF-kB complex plays a key role in neuroinflammatory responses in AD pathogenesis. In this study, we apply the proposed clustering algorithm to identify co-expression patterns with the NFkB1 in gene expression data from hippocampal tissue samples. Finally, we validate our experiments with biomedical literature search.

  7. An improved local immunization strategy for scale-free networks with a high degree of clustering

    NASA Astrophysics Data System (ADS)

    Xia, Lingling; Jiang, Guoping; Song, Yurong; Song, Bo

    2017-01-01

    The design of immunization strategies is an extremely important issue for disease or computer virus control and prevention. In this paper, we propose an improved local immunization strategy based on node's clustering which was seldom considered in the existing immunization strategies. The main aim of the proposed strategy is to iteratively immunize the node which has a high connectivity and a low clustering coefficient. To validate the effectiveness of our strategy, we compare it with two typical local immunization strategies on both real and artificial networks with a high degree of clustering. Simulations on these networks demonstrate that the performance of our strategy is superior to that of two typical strategies. The proposed strategy can be regarded as a compromise between computational complexity and immune effect, which can be widely applied in scale-free networks of high clustering, such as social network, technological networks and so on. In addition, this study provides useful hints for designing optimal immunization strategy for specific network.

  8. A robust fuzzy local information C-Means clustering algorithm.

    PubMed

    Krinidis, Stelios; Chatzis, Vassilios

    2010-05-01

    This paper presents a variation of fuzzy c-means (FCM) algorithm that provides image clustering. The proposed algorithm incorporates the local spatial information and gray level information in a novel fuzzy way. The new algorithm is called fuzzy local information C-Means (FLICM). FLICM can overcome the disadvantages of the known fuzzy c-means algorithms and at the same time enhances the clustering performance. The major characteristic of FLICM is the use of a fuzzy local (both spatial and gray level) similarity measure, aiming to guarantee noise insensitiveness and image detail preservation. Furthermore, the proposed algorithm is fully free of the empirically adjusted parameters (a, ¿(g), ¿(s), etc.) incorporated into all other fuzzy c-means algorithms proposed in the literature. Experiments performed on synthetic and real-world images show that FLICM algorithm is effective and efficient, providing robustness to noisy images.

  9. Perfect transmission through Anderson localized systems mediated by a cluster of localized modes.

    PubMed

    Choi, Wonjun; Park, Q-Han; Choi, Wonshik

    2012-08-27

    In a strongly scattering medium where Anderson localization takes place, constructive interference of local non-propagating waves dominate over the incoherent addition of propagating waves. This results in the disappearance of propagating waves within the medium, which significantly attenuates energy transmission. In this numerical study performed in the optical regime, we systematically found resonance modes, called eigenchannels, of a 2-D Anderson localized system that allow for the near-perfect energy transmission. We observed that the internal field distribution of these eigenchannels exhibit dense clustering of localized modes. This strongly suggests that the clustered resonance modes facilitate long-range energy flow of local waves. Our study explicitly elucidates the interplay between wave localization and transmission enhancement in the Anderson localization regime.

  10. Analysis of local bond-orientational order for liquid gallium at ambient pressure: Two types of cluster structures

    NASA Astrophysics Data System (ADS)

    Chen, Lin-Yuan; Tang, Ping-Han; Wu, Ten-Ming

    2016-07-01

    In terms of the local bond-orientational order (LBOO) parameters, a cluster approach to analyze local structures of simple liquids was developed. In this approach, a cluster is defined as a combination of neighboring seeds having at least nb local-orientational bonds and their nearest neighbors, and a cluster ensemble is a collection of clusters with a specified nb and number of seeds ns. This cluster analysis was applied to investigate the microscopic structures of liquid Ga at ambient pressure (AP). The liquid structures studied were generated through ab initio molecular dynamics simulations. By scrutinizing the static structure factors (SSFs) of cluster ensembles with different combinations of nb and ns, we found that liquid Ga at AP contained two types of cluster structures, one characterized by sixfold orientational symmetry and the other showing fourfold orientational symmetry. The SSFs of cluster structures with sixfold orientational symmetry were akin to the SSF of a hard-sphere fluid. On the contrary, the SSFs of cluster structures showing fourfold orientational symmetry behaved similarly as the anomalous SSF of liquid Ga at AP, which is well known for exhibiting a high-q shoulder. The local structures of a highly LBOO cluster whose SSF displayed a high-q shoulder were found to be more similar to the structure of β-Ga than those of other solid phases of Ga. More generally, the cluster structures showing fourfold orientational symmetry have an inclination to resemble more to β-Ga.

  11. Analysis of local bond-orientational order for liquid gallium at ambient pressure: Two types of cluster structures.

    PubMed

    Chen, Lin-Yuan; Tang, Ping-Han; Wu, Ten-Ming

    2016-07-14

    In terms of the local bond-orientational order (LBOO) parameters, a cluster approach to analyze local structures of simple liquids was developed. In this approach, a cluster is defined as a combination of neighboring seeds having at least nb local-orientational bonds and their nearest neighbors, and a cluster ensemble is a collection of clusters with a specified nb and number of seeds ns. This cluster analysis was applied to investigate the microscopic structures of liquid Ga at ambient pressure (AP). The liquid structures studied were generated through ab initio molecular dynamics simulations. By scrutinizing the static structure factors (SSFs) of cluster ensembles with different combinations of nb and ns, we found that liquid Ga at AP contained two types of cluster structures, one characterized by sixfold orientational symmetry and the other showing fourfold orientational symmetry. The SSFs of cluster structures with sixfold orientational symmetry were akin to the SSF of a hard-sphere fluid. On the contrary, the SSFs of cluster structures showing fourfold orientational symmetry behaved similarly as the anomalous SSF of liquid Ga at AP, which is well known for exhibiting a high-q shoulder. The local structures of a highly LBOO cluster whose SSF displayed a high-q shoulder were found to be more similar to the structure of β-Ga than those of other solid phases of Ga. More generally, the cluster structures showing fourfold orientational symmetry have an inclination to resemble more to β-Ga.

  12. Single-molecule localization software applied to photon counting imaging.

    PubMed

    Hirvonen, Liisa M; Kilfeather, Tiffany; Suhling, Klaus

    2015-06-01

    Centroiding in photon counting imaging has traditionally been accomplished by a single-step, noniterative algorithm, often implemented in hardware. Single-molecule localization techniques in superresolution fluorescence microscopy are conceptually similar, but use more sophisticated iterative software-based fitting algorithms to localize the fluorophore. Here, we discuss common features and differences between single-molecule localization and photon counting imaging and investigate the suitability of single-molecule localization software for photon event localization. We find that single-molecule localization software packages designed for superresolution microscopy-QuickPALM, rapidSTORM, and ThunderSTORM-can work well when applied to photon counting imaging with a microchannel-plate-based intensified camera system: photon event recognition can be excellent, fixed pattern noise can be low, and the microchannel plate pores can easily be resolved.

  13. Local matrix learning in clustering and applications for manifold visualization.

    PubMed

    Arnonkijpanich, Banchar; Hasenfuss, Alexander; Hammer, Barbara

    2010-05-01

    Electronic data sets are increasing rapidly with respect to both, size of the data sets and data resolution, i.e. dimensionality, such that adequate data inspection and data visualization have become central issues of data mining. In this article, we present an extension of classical clustering schemes by local matrix adaptation, which allows a better representation of data by means of clusters with an arbitrary spherical shape. Unlike previous proposals, the method is derived from a global cost function. The focus of this article is to demonstrate the applicability of this matrix clustering scheme to low-dimensional data embedding for data inspection. The proposed method is based on matrix learning for neural gas and manifold charting. This provides an explicit mapping of a given high-dimensional data space to low dimensionality. We demonstrate the usefulness of this method for data inspection and manifold visualization.

  14. Hybridization of evolutionary algorithms and local search by means of a clustering method.

    PubMed

    Martínez-Estudillo, Alfonso C; Hervás-Martínez, César; Martínez-Estudillo, Francisco J; García-Pedrajas, Nicolás

    2006-06-01

    This paper presents a hybrid evolutionary algorithm (EA) to solve nonlinear-regression problems. Although EAs have proven their ability to explore large search spaces, they are comparatively inefficient in fine tuning the solution. This drawback is usually avoided by means of local optimization algorithms that are applied to the individuals of the population. The algorithms that use local optimization procedures are usually called hybrid algorithms. On the other hand, it is well known that the clustering process enables the creation of groups (clusters) with mutually close points that hopefully correspond to relevant regions of attraction. Local-search procedures can then be started once in every such region. This paper proposes the combination of an EA, a clustering process, and a local-search procedure to the evolutionary design of product-units neural networks. In the methodology presented, only a few individuals are subject to local optimization. Moreover, the local optimization algorithm is only applied at specific stages of the evolutionary process. Our results show a favorable performance when the regression method proposed is compared to other standard methods.

  15. Local bladder cancer clusters in southeastern Michigan accounting for risk factors, covariates and residential mobility.

    PubMed

    Jacquez, Geoffrey M; Shi, Chen; Meliker, Jaymie R

    2015-01-01

    In case control studies disease risk not explained by the significant risk factors is the unexplained risk. Considering unexplained risk for specific populations, places and times can reveal the signature of unidentified risk factors and risk factors not fully accounted for in the case-control study. This potentially can lead to new hypotheses regarding disease causation. Global, local and focused Q-statistics are applied to data from a population-based case-control study of 11 southeast Michigan counties. Analyses were conducted using both year- and age-based measures of time. The analyses were adjusted for arsenic exposure, education, smoking, family history of bladder cancer, occupational exposure to bladder cancer carcinogens, age, gender, and race. Significant global clustering of cases was not found. Such a finding would indicate large-scale clustering of cases relative to controls through time. However, highly significant local clusters were found in Ingham County near Lansing, in Oakland County, and in the City of Jackson, Michigan. The Jackson City cluster was observed in working-ages and is thus consistent with occupational causes. The Ingham County cluster persists over time, suggesting a broad-based geographically defined exposure. Focused clusters were found for 20 industrial sites engaged in manufacturing activities associated with known or suspected bladder cancer carcinogens. Set-based tests that adjusted for multiple testing were not significant, although local clusters persisted through time and temporal trends in probability of local tests were observed. Q analyses provide a powerful tool for unpacking unexplained disease risk from case-control studies. This is particularly useful when the effect of risk factors varies spatially, through time, or through both space and time. For bladder cancer in Michigan, the next step is to investigate causal hypotheses that may explain the excess bladder cancer risk localized to areas of Oakland and Ingham

  16. Local Bladder Cancer Clusters in Southeastern Michigan Accounting for Risk Factors, Covariates and Residential Mobility

    PubMed Central

    Jacquez, Geoffrey M.; Shi, Chen; Meliker, Jaymie R.

    2015-01-01

    Background In case control studies disease risk not explained by the significant risk factors is the unexplained risk. Considering unexplained risk for specific populations, places and times can reveal the signature of unidentified risk factors and risk factors not fully accounted for in the case-control study. This potentially can lead to new hypotheses regarding disease causation. Methods Global, local and focused Q-statistics are applied to data from a population-based case-control study of 11 southeast Michigan counties. Analyses were conducted using both year- and age-based measures of time. The analyses were adjusted for arsenic exposure, education, smoking, family history of bladder cancer, occupational exposure to bladder cancer carcinogens, age, gender, and race. Results Significant global clustering of cases was not found. Such a finding would indicate large-scale clustering of cases relative to controls through time. However, highly significant local clusters were found in Ingham County near Lansing, in Oakland County, and in the City of Jackson, Michigan. The Jackson City cluster was observed in working-ages and is thus consistent with occupational causes. The Ingham County cluster persists over time, suggesting a broad-based geographically defined exposure. Focused clusters were found for 20 industrial sites engaged in manufacturing activities associated with known or suspected bladder cancer carcinogens. Set-based tests that adjusted for multiple testing were not significant, although local clusters persisted through time and temporal trends in probability of local tests were observed. Conclusion Q analyses provide a powerful tool for unpacking unexplained disease risk from case-control studies. This is particularly useful when the effect of risk factors varies spatially, through time, or through both space and time. For bladder cancer in Michigan, the next step is to investigate causal hypotheses that may explain the excess bladder cancer risk

  17. Localization and orientation of heavy-atom cluster compounds in protein crystals using molecular replacement.

    PubMed

    Dahms, Sven O; Kuester, Miriam; Streb, Carsten; Roth, Christian; Sträter, Norbert; Than, Manuel E

    2013-02-01

    Heavy-atom clusters (HA clusters) containing a large number of specifically arranged electron-dense scatterers are especially useful for experimental phase determination of large complex structures, weakly diffracting crystals or structures with large unit cells. Often, the determination of the exact orientation of the HA cluster and hence of the individual heavy-atom positions proves to be the critical step in successful phasing and subsequent structure solution. Here, it is demonstrated that molecular replacement (MR) with either anomalous or isomorphous differences is a useful strategy for the correct placement of HA cluster compounds. The polyoxometallate cluster hexasodium α-metatungstate (HMT) was applied in phasing the structure of death receptor 6. Even though the HA cluster is bound in alternate partially occupied orientations and is located at a special position, its correct localization and orientation could be determined at resolutions as low as 4.9 Å. The broad applicability of this approach was demonstrated for five different derivative crystals that included the compounds tantalum tetradecabromide and trisodium phosphotungstate in addition to HMT. The correct placement of the HA cluster depends on the length of the intramolecular vectors chosen for MR, such that both a larger cluster size and the optimal choice of the wavelength used for anomalous data collection strongly affect the outcome.

  18. RRW: repeated random walks on genome-scale protein networks for local cluster discovery

    PubMed Central

    Macropol, Kathy; Can, Tolga; Singh, Ambuj K

    2009-01-01

    Background We propose an efficient and biologically sensitive algorithm based on repeated random walks (RRW) for discovering functional modules, e.g., complexes and pathways, within large-scale protein networks. Compared to existing cluster identification techniques, RRW implicitly makes use of network topology, edge weights, and long range interactions between proteins. Results We apply the proposed technique on a functional network of yeast genes and accurately identify statistically significant clusters of proteins. We validate the biological significance of the results using known complexes in the MIPS complex catalogue database and well-characterized biological processes. We find that 90% of the created clusters have the majority of their catalogued proteins belonging to the same MIPS complex, and about 80% have the majority of their proteins involved in the same biological process. We compare our method to various other clustering techniques, such as the Markov Clustering Algorithm (MCL), and find a significant improvement in the RRW clusters' precision and accuracy values. Conclusion RRW, which is a technique that exploits the topology of the network, is more precise and robust in finding local clusters. In addition, it has the added flexibility of being able to find multi-functional proteins by allowing overlapping clusters. PMID:19740439

  19. Communication: Improved pair approximations in local coupled-cluster methods

    NASA Astrophysics Data System (ADS)

    Schwilk, Max; Usvyat, Denis; Werner, Hans-Joachim

    2015-03-01

    In local coupled cluster treatments the electron pairs can be classified according to the magnitude of their energy contributions or distances into strong, close, weak, and distant pairs. Different approximations are introduced for the latter three classes. In this communication, an improved simplified treatment of close and weak pairs is proposed, which is based on long-range cancellations of individually slowly decaying contributions in the amplitude equations. Benchmark calculations for correlation, reaction, and activation energies demonstrate that these approximations work extremely well, while pair approximations based on local second-order Møller-Plesset theory can lead to errors that are 1-2 orders of magnitude larger.

  20. Unsupervised feature relevance analysis applied to improve ECG heartbeat clustering.

    PubMed

    Rodríguez-Sotelo, J L; Peluffo-Ordoñez, D; Cuesta-Frau, D; Castellanos-Domínguez, G

    2012-10-01

    The computer-assisted analysis of biomedical records has become an essential tool in clinical settings. However, current devices provide a growing amount of data that often exceeds the processing capacity of normal computers. As this amount of information rises, new demands for more efficient data extracting methods appear. This paper addresses the task of data mining in physiological records using a feature selection scheme. An unsupervised method based on relevance analysis is described. This scheme uses a least-squares optimization of the input feature matrix in a single iteration. The output of the algorithm is a feature weighting vector. The performance of the method was assessed using a heartbeat clustering test on real ECG records. The quantitative cluster validity measures yielded a correctly classified heartbeat rate of 98.69% (specificity), 85.88% (sensitivity) and 95.04% (general clustering performance), which is even higher than the performance achieved by other similar ECG clustering studies. The number of features was reduced on average from 100 to 18, and the temporal cost was a 43% lower than in previous ECG clustering schemes.

  1. Local and global regularized concept factorization for image clustering

    NASA Astrophysics Data System (ADS)

    Qian, Bin; Tang, Zhenmin; Shen, Xiaobo; Shu, Zhenqiu

    2017-01-01

    Concept factorization (CF), as a popular matrix factorization technique, has recently attracted increasing attention in image clustering, due to the strong ability of dimension reduction and data representation. Existing CF variants only consider the local structure of data, but ignore the global structure information embedded in data, which is very crucial for data representation. To address the above issue, we propose an improved CF method, namely local and global regularized concept factorization (LGCF), by considering the local and global structures simultaneously. Specifically, the local geometric structure is depicted in LGCF via a hypergraph, which is capable of precisely capturing high-order geometrical information. In addition, to discover the global structure, we establish an unsupervised discriminant criterion, which characterizes the between-class scatter and the total scatter of the data with the help of latent features in LGCF. For the formulated LGCF, a multiplicative update rule is developed, and the convergence is rigorously proved. Extensive experiments on several real image datasets demonstrate the superiority of the proposed method over the state-of-the-art methods in terms of clustering accuracy and mutual information.

  2. The red-sequence of 72 WINGS local galaxy clusters

    NASA Astrophysics Data System (ADS)

    Valentinuzzi, T.; Poggianti, B. M.; Fasano, G.; D'Onofrio, M.; Moretti, A.; Ramella, M.; Biviano, A.; Fritz, J.; Varela, J.; Bettoni, D.; Vulcani, B.; Moles, M.; Couch, W. J.; Dressler, A.; Kjærgaard, P.; Omizzolo, A.; Cava, A.

    2011-12-01

    We study the color - magnitude red sequence and blue fraction of 72 X-ray selected galaxy clusters at z = 0.04-0.07 from the WINGS survey, searching for correlations between the characteristics of the red sequence (RS) and the environment. We consider the slope and scatter of the red sequence, the number ratio of red luminous-to-faint galaxies, the blue fraction, and the fractions of ellipticals, S0s, and spirals that compose the RS. None of these quantities correlate with the cluster velocity dispersion, X-ray luminosity, number of cluster substructures, BCG prevalence over next brightest galaxies, and the spatial concentration of ellipticals. The properties of the RS, instead, depend strongly on local galaxy density. Higher density regions have a smaller RS scatter, a higher luminous-to-faint ratio, a lower blue fraction, and a lower spiral fraction on the RS. Our results clearly illustrate the prominent effect of the local density in setting the epoch when galaxies become passive and join the red sequence, as opposed to the mass of the galaxy host structure.

  3. Agglomerative concentric hypersphere clustering applied to structural damage detection

    NASA Astrophysics Data System (ADS)

    Silva, Moisés; Santos, Adam; Santos, Reginaldo; Figueiredo, Eloi; Sales, Claudomiro; Costa, João C. W. A.

    2017-08-01

    The present paper proposes a novel cluster-based method, named as agglomerative concentric hypersphere (ACH), to detect structural damage in engineering structures. Continuous structural monitoring systems often require unsupervised approaches to automatically infer the health condition of a structure. However, when a structure is under linear and nonlinear effects caused by environmental and operational variability, data normalization procedures are also required to overcome these effects. The proposed approach aims, through a straightforward clustering procedure, to discover automatically the optimal number of clusters, representing the main state conditions of a structural system. Three initialization procedures are introduced to evaluate the impact of deterministic and stochastic initializations on the performance of this approach. The ACH is compared to state-of-the-art approaches, based on Gaussian mixture models and Mahalanobis squared distance, on standard data sets from a post-tensioned bridge located in Switzerland: the Z-24 Bridge. The proposed approach demonstrates more efficiency in modeling the normal condition of the structure and its corresponding main clusters. Furthermore, it reveals a better classification performance than the alternative ones in terms of false-positive and false-negative indications of damage, demonstrating a promising applicability in real-world structural health monitoring scenarios.

  4. Comparison of Different Generalizations of Clustering Coefficient and Local Efficiency for Weighted Undirected Graphs.

    PubMed

    Wang, Yu; Ghumare, Eshwar; Vandenberghe, Rik; Dupont, Patrick

    2017-02-01

    Binary undirected graphs are well established, but when these graphs are constructed, often a threshold is applied to a parameter describing the connection between two nodes. Therefore, the use of weighted graphs is more appropriate. In this work, we focus on weighted undirected graphs. This implies that we have to incorporate edge weights in the graph measures, which require generalizations of common graph metrics. After reviewing existing generalizations of the clustering coefficient and the local efficiency, we proposed new generalizations for these graph measures. To be able to compare different generalizations, a number of essential and useful properties were defined that ideally should be satisfied. We applied the generalizations to two real-world networks of different sizes. As a result, we found that not all existing generalizations satisfy all essential properties. Furthermore, we determined the best generalization for the clustering coefficient and local efficiency based on their properties and the performance when applied to two networks. We found that the best generalization of the clustering coefficient is [Formula: see text], defined in Miyajima and Sakuragawa ( 2014 ), while the best generalization of the local efficiency is [Formula: see text], proposed in this letter. Depending on the application and the relative importance of sensitivity and robustness to noise, other generalizations may be selected on the basis of the properties investigated in this letter.

  5. Analytical study of spatiotemporal chaos control by applying local injections

    PubMed

    Gang; Jinghua; Jihua; Xiangming; Yugui; Hu

    2000-09-01

    Spatiotemporal chaos control by applying local feedback injections is investigated analytically. The influence of gradient force on the controllability is investigated. It is shown that as the gradient force of the system is larger than a critical value, local control can reach very high efficiency to drive the turbulent system of infinite size to a regular target state by using a single control signal. The complex Ginzburg-Landau equation is used as a model to confirm the above analysis, and a four-wave-mixing mode is revealed to determine the dynamical behavior of the controlled system at the onset of instability.

  6. A Survey of Localized Star Clusters in NGC 1427A

    NASA Astrophysics Data System (ADS)

    Weaver, John R.; Gregg, Michael

    2016-01-01

    It is well established that galactic clusters provide dynamic environments in which to examine galaxy evolution. The starbursting dwarf irregular NGC 1427A presents an interesting case as it is being pulled into the nearby Fornax cluster at supersonic speeds, producing a visibly exceptional star formation rate and notably blue colors. It has been suggested that the highly deformed structure of NGC 1427A is due to ram pressure stripping as a result of interacting with a super-heated ICM provided by several nearby elliptical galaxies. The gas density profile of its leading edge is similar to a "bow-shock", containing several dozen super-star clusters (SSCs) and thousands of smaller star forming clusters. It is clearly evident that the properties of NGC 1427A change rapidly over relatively short distances. Using dithered HST/ACS images in Sloan equivalent g' r' i' z' and Hα filters, we present a morphological and photometric study of NGC 1427A using a novel approach in which stellar properties are measured from sources grouped within localized regions. Apertures are fitted for ~5000 sources at 4σ using a filter-combined master image. Four characteristic regions are chosen to study stellar properties, selected interactively through DS9. We then introduce COMET, a specially-designed source catalog handler for producing graphical figures of each region, cropping both spatially and photometrically. These are then batch-reviewed and analyzed using synthetic isochrones corresponding of each region. Hα bright sources are indicated to illustrate the significance of SSCs. Secondary analysis is carried out using smoothed color maps of source-subtracted diffuse light, yielding penetrative mapping of underlying stellar populations. We show for the first time how the dynamical stellar populations of NGC 1427A differ as a function of position across the surface of the galaxy, ultimately furthering our understanding of cluster interactions and the evolution of irregular galaxies

  7. Real-Time MEG Source Localization using Regional Clustering

    PubMed Central

    Dinh, Christoph; Strohmeier, Daniel; Luessi, Martin; Güllmar, Daniel; Baumgarten, Daniel; Haueisen, Jens; Hämäläinen, Matti S.

    2015-01-01

    With its millisecond temporal resolution, Magnetoencephalography (MEG) is well suited for real-time monitoring of brain activity. Real-time feedback allows the adaption of the experiment to the subject’s reaction and increases time efficiency by shortening acquisition and offline analysis. Two formidable challenges exist in real-time analysis: the low signal-to-noise ratio (SNR) and the limited time available for computations. Since the low SNR reduces the number of distinguishable sources, we propose an approach which downsizes the source space based on a cortical atlas and allows to discern the sources in the presence of noise. Each cortical region is represented by a small set of dipoles, which is obtained by a clustering algorithm. Using this approach, we adapted dynamic statistical parametric mapping (dSPM) for real-time source localization. In terms of point spread and crosstalk between regions the proposed clustering technique performs better than selecting spatially evenly distributed dipoles. We conducted real-time source localization on MEG data from an auditory experiment. The results demonstrate that the proposed real-time method localizes sources reliably in the superior temporal gyrus. We conclude that real-time source estimation based on MEG is a feasible, useful addition to the standard on-line processing methods, and enables feedback based on neural activity during the measurements. PMID:25782980

  8. Real-Time MEG Source Localization Using Regional Clustering.

    PubMed

    Dinh, Christoph; Strohmeier, Daniel; Luessi, Martin; Güllmar, Daniel; Baumgarten, Daniel; Haueisen, Jens; Hämäläinen, Matti S

    2015-11-01

    With its millisecond temporal resolution, Magnetoencephalography (MEG) is well suited for real-time monitoring of brain activity. Real-time feedback allows the adaption of the experiment to the subject's reaction and increases time efficiency by shortening acquisition and off-line analysis. Two formidable challenges exist in real-time analysis: the low signal-to-noise ratio (SNR) and the limited time available for computations. Since the low SNR reduces the number of distinguishable sources, we propose an approach which downsizes the source space based on a cortical atlas and allows to discern the sources in the presence of noise. Each cortical region is represented by a small set of dipoles, which is obtained by a clustering algorithm. Using this approach, we adapted dynamic statistical parametric mapping for real-time source localization. In terms of point spread and crosstalk between regions the proposed clustering technique performs better than selecting spatially evenly distributed dipoles. We conducted real-time source localization on MEG data from an auditory experiment. The results demonstrate that the proposed real-time method localizes sources reliably in the superior temporal gyrus. We conclude that real-time source estimation based on MEG is a feasible, useful addition to the standard on-line processing methods, and enables feedback based on neural activity during the measurements.

  9. Vortex configuration in the presence of local magnetic field and locally applied stress

    NASA Astrophysics Data System (ADS)

    Wissberg, Shai; Kremen, Anna; Shperber, Yishai; Kalisky, Beena

    2017-02-01

    Vortex configuration is determined by the repulsive interaction, which becomes dominant with increasing vortex density, by the pinning potential, and by other considerations such as the local magnetic fields, currents flowing in the sample, or as we showed recently, by local stress applied on the sample. In this work we describe different ways to control vortex configuration using scanning SQUID microscopy.

  10. Accounting for Limited Detection Efficiency and Localization Precision in Cluster Analysis in Single Molecule Localization Microscopy

    PubMed Central

    Shivanandan, Arun; Unnikrishnan, Jayakrishnan; Radenovic, Aleksandra

    2015-01-01

    Single Molecule Localization Microscopy techniques like PhotoActivated Localization Microscopy, with their sub-diffraction limit spatial resolution, have been popularly used to characterize the spatial organization of membrane proteins, by means of quantitative cluster analysis. However, such quantitative studies remain challenged by the techniques’ inherent sources of errors such as a limited detection efficiency of less than 60%, due to incomplete photo-conversion, and a limited localization precision in the range of 10 – 30nm, varying across the detected molecules, mainly depending on the number of photons collected from each. We provide analytical methods to estimate the effect of these errors in cluster analysis and to correct for them. These methods, based on the Ripley’s L(r) – r or Pair Correlation Function popularly used by the community, can facilitate potentially breakthrough results in quantitative biology by providing a more accurate and precise quantification of protein spatial organization. PMID:25794150

  11. Global, local and focused geographic clustering for case-control data with residential histories

    PubMed Central

    Jacquez, Geoffrey M; Kaufmann, Andy; Meliker, Jaymie; Goovaerts, Pierre; AvRuskin, Gillian; Nriagu, Jerome

    2005-01-01

    Background This paper introduces a new approach for evaluating clustering in case-control data that accounts for residential histories. Although many statistics have been proposed for assessing local, focused and global clustering in health outcomes, few, if any, exist for evaluating clusters when individuals are mobile. Methods Local, global and focused tests for residential histories are developed based on sets of matrices of nearest neighbor relationships that reflect the changing topology of cases and controls. Exposure traces are defined that account for the latency between exposure and disease manifestation, and that use exposure windows whose duration may vary. Several of the methods so derived are applied to evaluate clustering of residential histories in a case-control study of bladder cancer in south eastern Michigan. These data are still being collected and the analysis is conducted for demonstration purposes only. Results Statistically significant clustering of residential histories of cases was found but is likely due to delayed reporting of cases by one of the hospitals participating in the study. Conclusion Data with residential histories are preferable when causative exposures and disease latencies occur on a long enough time span that human mobility matters. To analyze such data, methods are needed that take residential histories into account. PMID:15784151

  12. Local clustering in scale-free networks with hidden variables

    NASA Astrophysics Data System (ADS)

    van der Hofstad, Remco; Janssen, A. J. E. M.; van Leeuwaarden, Johan S. H.; Stegehuis, Clara

    2017-02-01

    We investigate the presence of triangles in a class of correlated random graphs in which hidden variables determine the pairwise connections between vertices. The class rules out self-loops and multiple edges. We focus on the regime where the hidden variables follow a power law with exponent τ ∈(2 ,3 ) , so that the degrees have infinite variance. The natural cutoff hc characterizes the largest degrees in the hidden variable models, and a structural cutoff hs introduces negative degree correlations (disassortative mixing) due to the infinite-variance degrees. We show that local clustering decreases with the hidden variable (or degree). We also determine how the average clustering coefficient C scales with the network size N , as a function of hs and hc. For scale-free networks with exponent 2 <τ <3 and the default choices hs˜N1 /2 and hc˜N1 /(τ -1 ) this gives C ˜N2 -τlnN for the universality class at hand. We characterize the extremely slow decay of C when τ ≈2 and show that for τ =2.1 , say, clustering starts to vanish only for networks as large as N =109 .

  13. Localized application of soil organic matter shifts distribution of cluster roots of white lupin in the soil profile due to localized release of phosphorus

    PubMed Central

    Li, Hai-Gang; Shen, Jian-Bo; Zhang, Fu-Suo; Lambers, Hans

    2010-01-01

    Background and Aims Phosphorus (P) is a major factor controlling cluster-root formation. Cluster-root proliferation tends to concentrate in organic matter (OM)-rich surface-soil layers, but the nature of this response of cluster-root formation to OM is not clear. Cluster-root proliferation in response to localized application of OM was characterized in Lupinus albus (white lupin) grown in stratified soil columns to test if the stimulating effect of OM on cluster-root formation was due to (a) P release from breakdown of OM; (b) a decrease in soil density; or (c) effects of micro-organisms other than releasing P from OM. Methods Lupin plants were grown in three-layer stratified soil columns where P was applied at 0 or 330 mg P kg−1 to create a P-deficient or P-sufficient background, and OM, phytate mixed with OM, or perlite was applied to the top or middle layers with or without sterilization. Key Results Non-sterile OM stimulated cluster-root proliferation and root length, and this effect became greater when phytate was supplied in the presence of OM. Both sterile OM and perlite significantly decreased cluster-root formation in the localized layers. The OM position did not change the proportion of total cluster roots to total roots in dry biomass among no-P treatments, but more cluster roots were concentrated in the OM layers with a decreased proportion in other places. Conclusions Localized application of non-sterile OM or phytate plus OM stimulated cluster-root proliferation of L. albus in the localized layers. This effect is predominantly accounted for by P release from breakdown of OM or phytate, but not due to a change in soil density associated with OM. No evidence was found for effects of micro-organisms in OM other than those responsible for P release. PMID:20150198

  14. Integration of cloud, grid and local cluster resources with DIRAC

    NASA Astrophysics Data System (ADS)

    Fifield, Tom; Carmona, Ana; Casajús, Adrián; Graciani, Ricardo; Sevior, Martin

    2011-12-01

    Grid computing was developed to provide users with uniform access to large-scale distributed resources. This has worked well, however there are significant resources available to the scientific community that do not follow this paradigm - those on cloud infrastructure providers, HPC supercomputers or local clusters. DIRAC (Distributed Infrastructure with Remote Agent Control) was originally designed to support direct submission to the Local Resource Management Systems (LRMS) of such clusters for LHCb, matured to support grid workflows and has recently been updated to support Amazon's Elastic Compute Cloud. This raises a number of new possibilities - by opening avenues to new resources, virtual organisations can change their resources with usage patterns and use these dedicated facilities for a given time. For example, user communities such as High Energy Physics experiments, have computing tasks with a wide variety of requirements in terms of CPU, data access or memory consumption, and their usage profile is never constant throughout the year. Having the possibility to transparently absorb peaks on the demand for these kinds of tasks using Cloud resources could allow a reduction in the overall cost of the system. This paper investigates interoperability by following a recent large-scale production excercise utilising resources from these three different paradigms, during the 2010 Belle Monte Carlo run. Through this, it discusses the challenges and opportunities of such a model.

  15. A method for improved clustering and classification of microscopy images using quantitative co-localization coefficients

    PubMed Central

    2012-01-01

    Background The localization of proteins to specific subcellular structures in eukaryotic cells provides important information with respect to their function. Fluorescence microscopy approaches to determine localization distribution have proved to be an essential tool in the characterization of unknown proteins, and are now particularly pertinent as a result of the wide availability of fluorescently-tagged constructs and antibodies. However, there are currently very few image analysis options able to effectively discriminate proteins with apparently similar distributions in cells, despite this information being important for protein characterization. Findings We have developed a novel method for combining two existing image analysis approaches, which results in highly efficient and accurate discrimination of proteins with seemingly similar distributions. We have combined image texture-based analysis with quantitative co-localization coefficients, a method that has traditionally only been used to study the spatial overlap between two populations of molecules. Here we describe and present a novel application for quantitative co-localization, as applied to the study of Rab family small GTP binding proteins localizing to the endomembrane system of cultured cells. Conclusions We show how quantitative co-localization can be used alongside texture feature analysis, resulting in improved clustering of microscopy images. The use of co-localization as an additional clustering parameter is non-biased and highly applicable to high-throughput image data sets. PMID:22681635

  16. Applying clustering approach in predictive uncertainty estimation: a case study with the UNEEC method

    NASA Astrophysics Data System (ADS)

    Dogulu, Nilay; Solomatine, Dimitri; Lal Shrestha, Durga

    2014-05-01

    Within the context of flood forecasting, assessment of predictive uncertainty has become a necessity for most of the modelling studies in operational hydrology. There are several uncertainty analysis and/or prediction methods available in the literature; however, most of them rely on normality and homoscedasticity assumptions for model residuals occurring in reproducing the observed data. This study focuses on a statistical method analyzing model residuals without having any assumptions and based on a clustering approach: Uncertainty Estimation based on local Errors and Clustering (UNEEC). The aim of this work is to provide a comprehensive evaluation of the UNEEC method's performance in view of clustering approach employed within its methodology. This is done by analyzing normality of model residuals and comparing uncertainty analysis results (for 50% and 90% confidence level) with those obtained from uniform interval and quantile regression methods. An important part of the basis by which the methods are compared is analysis of data clusters representing different hydrometeorological conditions. The validation measures used are PICP, MPI, ARIL and NUE where necessary. A new validation measure linking prediction interval to the (hydrological) model quality - weighted mean prediction interval (WMPI) - is also proposed for comparing the methods more effectively. The case study is Brue catchment, located in the South West of England. A different parametrization of the method than its previous application in Shrestha and Solomatine (2008) is used, i.e. past error values in addition to discharge and effective rainfall is considered. The results show that UNEEC's notable characteristic in its methodology, i.e. applying clustering to data of predictors upon which catchment behaviour information is encapsulated, contributes increased accuracy of the method's results for varying flow conditions. Besides, classifying data so that extreme flow events are individually

  17. On the nature of local instabilities in rotating galactic coronae and cool cores of galaxy clusters

    SciTech Connect

    Nipoti, Carlo; Posti, Lorenzo

    2014-09-01

    A long-standing question is whether radiative cooling can lead to local condensation of cold gas in the hot atmospheres of galaxies and galaxy clusters. We address this problem by studying the nature of local instabilities in rotating, stratified, weakly magnetized, optically thin plasmas in the presence of radiative cooling and anisotropic thermal conduction. For both axisymmetric and nonaxisymmetric linear perturbations, we provide general equations which can be applied locally to specific systems to establish whether they are unstable and, in case of instability, to determine the kind of evolution (monotonically growing or overstable) and the growth rates of the unstable modes. We present results for models of rotating plasmas representative of Milky-Way-like galaxy coronae and cool-cores of galaxy clusters. We show that the unstable modes arise from a combination of thermal, magnetothermal, magnetorotational, and heat-flux-driven buoyancy instabilities. Local condensation of cold clouds tends to be hampered in cluster cool cores, while it is possible under certain conditions in rotating galactic coronae. If the magnetic field is sufficiently weak, then the magnetorotational instability is dominant even in these pressure-supported systems.

  18. Integrin clustering as a result of local membrane deformations and local signaling feedbacks

    NASA Astrophysics Data System (ADS)

    Felizzi, Federico; Iber, Dagmar

    2014-08-01

    Integrins are essential receptors for the development and functioning of multicellular animals because they mediate cell adhesion and migration, and regulate cell proliferation and apoptosis. Ligand-dependent activation of integrins involves the formation of receptor clusters and this has been accounted both to extracellular forces as mediated by the glycocalyx as well as to intracellular forces mediated by the cytoskeleton. Here we describe a Monte Carlo simulation that considers both the binding processes on the membrane as well as the intracellular signaling processes that stabilize the open integrin conformation. We show that integrin clustering can result both from the effects of integrin avidity, as a result of membrane deformations, as well as from the locally enhanced availability of talins in the open conformation, as a result of local positive feedback signaling via PIPKIγ and PIP2. The model was carefully parameterized based on reported quantitative data and reproduces a wide range of experimental data, including results that previously appeared inconsistent.

  19. Apply a hydrological model to estimate local temperature trends

    NASA Astrophysics Data System (ADS)

    Igarashi, Masao; Shinozawa, Tatsuya

    2014-03-01

    Continuous times series {f(x)} such as a depth of water is written f(x) = T(x)+P(x)+S(x)+C(x) in hydrological science where T(x),P(x),S(x) and C(x) are called the trend, periodic, stochastic and catastrophic components respectively. We simplify this model and apply it to the local temperature data such as given E. Halley (1693), the UK (1853-2010), Germany (1880-2010), Japan (1876-2010). We also apply the model to CO2 data. The model coefficients are evaluated by a symbolic computation by using a standard personal computer. The accuracy of obtained nonlinear curve is evaluated by the arithmetic mean of relative errors between the data and estimations. E. Halley estimated the temperature of Gresham College from 11/1692 to 11/1693. The simplified model shows that the temperature at the time rather cold compared with the recent of London. The UK and Germany data sets show that the maximum and minimum temperatures increased slowly from the 1890s to 1940s, increased rapidly from the 1940s to 1980s and have been decreasing since the 1980s with the exception of a few local stations. The trend of Japan is similar to these results.

  20. Applying Best Practices to Florida Local Government Retrofit Programs

    SciTech Connect

    McIlvaine, J.; Sutherland, K.

    2013-12-01

    In some communities, local government and non-profit entities have funds to purchase and renovate distressed, foreclosed homes for resale in the affordable housing market. Numerous opportunities to improve whole house energy efficiency are inherent in these comprehensive renovations. BA-PIRC worked together in a multi-year field study making recommendations in individual homes, meanwhile compiling improvement costs, projected energy savings, practical challenges, and labor force factors surrounding common energy-related renovation measures. The field study, Phase 1 of this research, resulted in a set of best practices appropriate to the current labor pool and market conditions in central Florida to achieve projected annual energy savings of 15-30% and higher. This report describes Phase 2 of the work where researchers worked with a local government partner to implement and refine the 'current best practices.' A simulation study was conducted to characterize savings potential under three sets of conditions representing varying replacement needs for energy-related equipment and envelope components. The three scenarios apply readily to the general remodeling industry as for renovation of foreclosed homes for the affordable housing market. Our new local government partner, the City of Melbourne, implemented the best practices in a community-scale renovation program that included ten homes in 2012.

  1. Applying Best Practices to Florida Local Government Retrofit Programs

    SciTech Connect

    McIlvaine, J.; Sutherland, K.

    2013-12-01

    In some communities, local government and non-profit entities have funds to purchase and renovate distressed, foreclosed homes for resale in the affordable housing market. Numerous opportunities to improve whole house energy efficiency are inherent in these comprehensive renovations. BA-PIRC worked together in a multiyear field study making recommendations in individual homes, meanwhile compiling improvement costs, projected energy savings, practical challenges, and labor force factors surrounding common energy-related renovation measures. The field study, Phase 1 of this research, resulted in a set of best practices appropriate to the current labor pool and market conditions in central Florida to achieve projected annual energy savings of 15%-30% and higher. This report describes Phase 2 of the work where researchers worked with a local government partner to implement and refine the "current best practices". A simulation study was conducted to characterize savings potential under three sets of conditions representing varying replacement needs for energy-related equipment and envelope components. The three scenarios apply readily to the general remodeling industry as for renovation of foreclosed homes for the affordable housing market. The new local government partner, the City of Melbourne, implemented the best practices in a community-scale renovation program that included ten homes in 2012.

  2. Nearest Hyperplane Distance Neighbor Clustering algorithm Applied to Gene Co-Expression Analysis in Alzheimer’s Disease

    PubMed Central

    Pasluosta, Cristian F.; Dua, Prerna; Lukiw, Walter J.

    2013-01-01

    Microarray analysis can contribute considerably to the understanding of biologically significant cellular mechanisms that yield novel information regarding co-regulated sets of gene patterns. Clustering is one of the most popular tools for analyzing DNA microarray data. In this paper, we present an unsupervised clustering algorithm based on the K-local hyperplane distance nearest-neighbor classifier (HKNN). We adapted the well-known nearest neighbor clustering algorithm for use with hyperplane distance. The result is a simple and computationally inexpensive unsupervised clustering algorithm that can be applied to high-dimensional data. It has been reported that the NFkB1 gene is progressively over-expressed in moderate-to-severe Alzheimer’s disease (AD) cases, and that the NF-kB complex plays a key role in neuroinflammatory responses in AD pathogenesis. In this study, we apply the proposed clustering algorithm to identify co-expression patterns with the NFkB1 in gene expression data from hippocampal tissue samples. Finally, we validate our experiments with biomedical literature search. PMID:22255598

  3. EEG and MEG source localization using recursively applied (RAP) MUSIC

    SciTech Connect

    Mosher, J.C.; Leahy, R.M.

    1996-12-31

    The multiple signal characterization (MUSIC) algorithm locates multiple asynchronous dipolar sources from electroencephalography (EEG) and magnetoencephalography (MEG) data. A signal subspace is estimated from the data, then the algorithm scans a single dipole model through a three-dimensional head volume and computes projections onto this subspace. To locate the sources, the user must search the head volume for local peaks in the projection metric. Here we describe a novel extension of this approach which we refer to as RAP (Recursively APplied) MUSIC. This new procedure automatically extracts the locations of the sources through a recursive use of subspace projections, which uses the metric of principal correlations as a multidimensional form of correlation analysis between the model subspace and the data subspace. The dipolar orientations, a form of `diverse polarization,` are easily extracted using the associated principal vectors.

  4. Source localization using recursively applied and projected (RAP) MUSIC

    SciTech Connect

    Mosher, J.C.; Leahy, R.M.

    1998-03-01

    A new method for source localization is described that is based on a modification of the well known multiple signal classification (MUSIC) algorithm. In classical MUSIC, the array manifold vector is projected onto an estimate of the signal subspace, but errors in the estimate can make location of multiple sources difficult. Recursively applied and projected (RAP) MUSIC uses each successively located source to form an intermediate array gain matrix, and projects both the array manifold and the signal subspace estimate into its orthogonal complement. The MUSIC projection is then performed in this reduced subspace. Using the metric of principal angles, the authors describe a general form of the RAP-MUSIC algorithm for the case of diversely polarized sources. Through a uniform linear array simulation, the authors demonstrate the improved Monte Carlo performance of RAP-MUSIC relative to MUSIC and two other sequential subspace methods, S and IES-MUSIC.

  5. Localization Strategies in WSNs as applied to Landslide Monitoring (Invited)

    NASA Astrophysics Data System (ADS)

    Massa, A.; Robol, F.; Polo, A.; Giarola, E.; Viani, F.

    2013-12-01

    In the last years, heterogeneous integrated smart systems based on wireless sensor network (WSN) technology have been developed at the ELEDIA Research Center of the University of Trento [1]. One of the key features of WSNs as applied to distributed monitoring is that, while the capabilities of each single sensor node is limited, the implementation of cooperative schemes throughout the whole network enables the solution of even complex tasks, as the landslide monitoring. The capability of localizing targets respect to the position of the sensor nodes turns out to be fundamental in those application fields where relative movements arise. The main properties like the target typology, the movement characteristics, and the required localization resolution are different changing the reference scenario. However, the common key issue is still the localization of moving targets within the area covered by the sensor network. Many experiences were preparatory for the challenging activities in the field of landslide monitoring where the basic idea is mostly that of detecting slight soil movements. Among them, some examples of WSN-based systems experimentally applied to the localization of people [2] and wildlife [3] have been proposed. More recently, the WSN backbone as well as the investigated sensing technologies have been customized for monitoring superficial movements of the soil. The relative positions of wireless sensor nodes deployed where high probability of landslide exists is carefully monitored to forecast dangerous events. Multiple sensors like ultrasound, laser, high precision GPS, for the precise measurement of relative distances between the nodes of the network and the absolute positions respect to reference targets have been integrated in a prototype system. The millimeter accuracy in the position estimation enables the detection of small soil modifications and to infer the superficial evolution profile of the landslide. This information locally acquired also

  6. Local Bifurcation and Instability Theory Applied to Formability Analysis

    NASA Astrophysics Data System (ADS)

    Buco, B. D.; Oliveira, M. C.; Alves, J. L.; Menezes, L. F.; Ito, K.; Mori, N.

    2010-06-01

    Sheet metal forming components are typically studied with the aid of finite element method based virtual tryout tools, since they allow to save money, time and effort in the design, production and process set-up of deep drawn parts. In all these development phases the analysis of defects is performed with the aid of the material forming limit diagram (FLD), since it allows defining a safe region that reduces: (i) necking; (ii) wrinkling and (iii) large deformation occurrence. It is known that the FLD represented in the strain space presents some disadvantages. The local bifurcation criterion proposed by Ito and Goya defines the critical state for a local bifurcation to set in, as a function of the stress level to work-hardening rate ratio. Thus, the main advantage is that the FLD represented in the stress plane is completely objective [1]. In this work the Ito and Goya model is used to evaluate formability, as well fracture mode and direction along different strain paths: (i) uniaxial tension; (ii) equibiaxial stretch; and (iii) plane-strain. All numerical simulations are performed with the in-house code DD3IMP [2, 3] and NXT [4] in which the Ito and Goya model is implemented, is applied to analyze the results.

  7. What determines large scale galaxy clustering: halo mass or local density?

    NASA Astrophysics Data System (ADS)

    Pujol, Arnau; Hoffmann, Kai; Jiménez, Noelia; Gaztañaga, Enrique

    2017-02-01

    Using a dark matter simulation we show how halo bias is determined by local density and not by halo mass. This is not totally surprising as, according to the peak-background split model, local matter density (bar δ) is the property that constrains bias at large scales. Massive haloes have a high clustering because they reside in high density regions. Small haloes can be found in a wide range of environments which differentially determine their clustering amplitudes. This contradicts the assumption made by standard halo occupation distribution (HOD) models that bias and occupation of haloes is determined solely by their mass. We show that the bias of central galaxies from semi-analytic models of galaxy formation as a function of luminosity and colour is therefore not correctly predicted by the standard HOD model. Using bar δ (of matter or galaxies) instead of halo mass, the HOD model correctly predicts galaxy bias. These results indicate the need to include information about local density and not only mass in order to correctly apply HOD analysis in these galaxy samples. This new model can be readily applied to observations and has the advantage that, in contrast with the dark matter halo mass, the galaxy density can be directly observed.

  8. Improved K-means clustering algorithm for exploring local protein sequence motifs representing common structural property.

    PubMed

    Zhong, Wei; Altun, Gulsah; Harrison, Robert; Tai, Phang C; Pan, Yi

    2005-09-01

    Information about local protein sequence motifs is very important to the analysis of biologically significant conserved regions of protein sequences. These conserved regions can potentially determine the diverse conformation and activities of proteins. In this work, recurring sequence motifs of proteins are explored with an improved K-means clustering algorithm on a new dataset. The structural similarity of these recurring sequence clusters to produce sequence motifs is studied in order to evaluate the relationship between sequence motifs and their structures. To the best of our knowledge, the dataset used by our research is the most updated dataset among similar studies for sequence motifs. A new greedy initialization method for the K-means algorithm is proposed to improve traditional K-means clustering techniques. The new initialization method tries to choose suitable initial points, which are well separated and have the potential to form high-quality clusters. Our experiments indicate that the improved K-means algorithm satisfactorily increases the percentage of sequence segments belonging to clusters with high structural similarity. Careful comparison of sequence motifs obtained by the improved and traditional algorithms also suggests that the improved K-means clustering algorithm may discover some relatively weak and subtle sequence motifs, which are undetectable by the traditional K-means algorithms. Many biochemical tests reported in the literature show that these sequence motifs are biologically meaningful. Experimental results also indicate that the improved K-means algorithm generates more detailed sequence motifs representing common structures than previous research. Furthermore, these motifs are universally conserved sequence patterns across protein families, overcoming some weak points of other popular sequence motifs. The satisfactory result of the experiment suggests that this new K-means algorithm may be applied to other areas of bioinformatics

  9. A local framework for calculating coupled cluster singles and doubles excitation energies (LoFEx-CCSD)

    DOE PAGES

    Baudin, Pablo; Bykov, Dmytro; Liakh, Dmitry I.; ...

    2017-02-22

    Here, the recently developed Local Framework for calculating Excitation energies (LoFEx) is extended to the coupled cluster singles and doubles (CCSD) model. In the new scheme, a standard CCSD excitation energy calculation is carried out within a reduced excitation orbital space (XOS), which is composed of localised molecular orbitals and natural transition orbitals determined from time-dependent Hartree–Fock theory. The presented algorithm uses a series of reduced second-order approximate coupled cluster singles and doubles (CC2) calculations to optimise the XOS in a black-box manner. This ensures that the requested CCSD excitation energies have been determined to a predefined accuracy compared tomore » a conventional CCSD calculation. We present numerical LoFEx-CCSD results for a set of medium-sized organic molecules, which illustrate the black-box nature of the approach and the computational savings obtained for transitions that are local compared to the size of the molecule. In fact, for such local transitions, the LoFEx-CCSD scheme can be applied to molecular systems where a conventional CCSD implementation is intractable.« less

  10. Comparison of local, semi-microscopic, and microscopic three-cluster models

    SciTech Connect

    Theeten, M.; Baye, D.; Descouvemont, P.

    2006-10-15

    Two different three-body models are compared with a fully antisymmetrized microscopic three-cluster model. The local model makes use of local effective interactions involving forbidden states among the three particles. In the semi-microscopic model, nonlocal two-body interactions are derived within the resonating-group method from the same nucleon-nucleon effective forces as in the microscopic model. In both cases, calculations are performed in hyperspherical coordinates with the Lagrange-mesh method. The role of forbidden states and their elimination are discussed. The models are applied to an {alpha}{alpha}n description of {sup 9}Be and an {alpha}nn description of {sup 6}He. The local model results are affected by almost forbidden states and may be unrealistic for {sup 9}Be. A comparison of the microscopic and semi-microscopic models shows that the effect of exchanges involving the three clusters is weak. An overbinding of {sup 9}Be cannot be avoided with nucleon-nucleon forces reproducing {alpha}n and {alpha}{alpha} scattering properties. On the contrary, {sup 6}He is underbound under the same conditions. This can probably be attributed to a lack of three-nucleon forces.

  11. A clustering approach applied to time-lapse ERT interpretation - Case study of Lascaux cave

    NASA Astrophysics Data System (ADS)

    Xu, Shan; Sirieix, Colette; Riss, Joëlle; Malaurent, Philippe

    2017-09-01

    The Lascaux cave, located in southwest France, is one of the most important prehistoric cave in the world that shows Paleolithic paintings. This study aims to characterize the structure of the weathered epikarst setting located above the cave using Time-Lapse Electrical Resistivity Tomography (ERT) combined with local hydrogeological and climatic environmental data. Twenty ERT profiles were carried out for two years and helped us to record the seasonal and spatial variations of the electrical resistivity of the hydraulic upstream area of the Lascaux cave. The 20 interpreted resistivity models were merged into a single synthetic model using a multidimensional statistical method (Hierarchical Agglomerative Clustering). The individual blocks from the synthetic model associated with a similar resistivity variability were gathered into 7 clusters. We combined the resistivity temporal variations with climatic and hydrogeological data to propose a geo-electrical model that relates to a conceptual geological model. We provide a geological interpretation for each cluster regarding epikarst features. The superficial clusters (no 1 & 2) are linked to effective rainfall and trees, probably a fractured limestone. Another two clusters (no 6 & 7) are linked to detrital formations (sand and clay respectively). The cluster 3 may correspond to a marly limestone that forms a non-permeable horizon. Finally, the electrical behavior of the last two clusters (no 4 & 5) is correlated with the variation of flow rate; they may be a privileged feed zone of the flow in the cave.

  12. Localized diabatization applied to excitons in molecular crystals

    NASA Astrophysics Data System (ADS)

    Jin, Zuxin; Subotnik, Joseph E.

    2017-06-01

    Traditional ab initio electronic structure calculations of periodic systems yield delocalized eigenstates that should be understood as adiabatic states. For example, excitons are bands of extended states which superimpose localized excitations on every lattice site. However, in general, in order to study the effects of nuclear motion on exciton transport, it is standard to work with a localized description of excitons, especially in a hopping regime; even in a band regime, a localized description can be helpful. To extract localized excitons from a band requires essentially a diabatization procedure. In this paper, three distinct methods are proposed for such localized diabatization: (i) a simple projection method, (ii) a more general Pipek-Mezey localization scheme, and (iii) a variant of Boys diabatization. Approaches (i) and (ii) require localized, single-particle Wannier orbitals, while approach (iii) has no such dependence. These methods should be very useful for studying energy transfer through solids with ab initio calculations.

  13. Profiling local optima in K-means clustering: developing a diagnostic technique.

    PubMed

    Steinley, Douglas

    2006-06-01

    Using the cluster generation procedure proposed by D. Steinley and R. Henson (2005), the author investigated the performance of K-means clustering under the following scenarios: (a) different probabilities of cluster overlap; (b) different types of cluster overlap; (c) varying samples sizes, clusters, and dimensions; (d) different multivariate distributions of clusters; and (e) various multidimensional data structures. The results are evaluated in terms of the Hubert-Arabie adjusted Rand index, and several observations concerning the performance of K-means clustering are made. Finally, the article concludes with the proposal of a diagnostic technique indicating when the partitioning given by a K-means cluster analysis can be trusted. By combining the information from several observable characteristics of the data (number of clusters, number of variables, sample size, etc.) with the prevalence of unique local optima in several thousand implementations of the K-means algorithm, the author provides a method capable of guiding key data-analysis decisions.

  14. A local energy consumption prediction-based clustering protocol for wireless sensor networks.

    PubMed

    Yu, Jiguo; Feng, Li; Jia, Lili; Gu, Xin; Yu, Dongxiao

    2014-12-03

    Clustering is a fundamental and effective technique for utilizing sensor nodes' energy and extending the network lifetime for wireless sensor networks. In this paper, we propose a novel clustering protocol, LECP-CP (local energy consumption prediction-based clustering protocol), the core of which includes a novel cluster head election algorithm and an inter-cluster communication routing tree construction algorithm, both based on the predicted local energy consumption ratio of nodes. We also provide a more accurate and realistic cluster radius to minimize the energy consumption of the entire network. The global energy consumption can be optimized by the optimization of the local energy consumption, and the energy consumption among nodes can be balanced well. Simulation results validate our theoretical analysis and show that LECP-CP has high efficiency of energy utilization, good scalability and significant improvement in the network lifetime.

  15. A Special Local Clustering Algorithm for Identifying the Genes Associated With Alzheimer’s Disease

    PubMed Central

    Pang, Chao-Yang; Hu, Wei; Hu, Ben-Qiong; Shi, Ying; Vanderburg, Charles R.; Rogers, Jack T.

    2010-01-01

    Clustering is the grouping of similar objects into a class. Local clustering feature refers to the phenomenon whereby one group of data is separated from another, and the data from these different groups are clustered locally. A compact class is defined as one cluster in which all similar elements cluster tightly within the cluster. Herein, the essence of the local clustering feature, revealed by mathematical manipulation, results in a novel clustering algorithm termed as the special local clustering (SLC) algorithm that was used to process gene microarray data related to Alzheimer’s disease (AD). SLC algorithm was able to group together genes with similar expression patterns and identify significantly varied gene expression values as isolated points. If a gene belongs to a compact class in control data and appears as an isolated point in incipient, moderate and/or severe AD gene microarray data, this gene is possibly associated with AD. Application of a clustering algorithm in disease-associated gene identification such as in AD is rarely reported. PMID:20089478

  16. A Bayesian cluster analysis method for single-molecule localization microscopy data.

    PubMed

    Griffié, Juliette; Shannon, Michael; Bromley, Claire L; Boelen, Lies; Burn, Garth L; Williamson, David J; Heard, Nicholas A; Cope, Andrew P; Owen, Dylan M; Rubin-Delanchy, Patrick

    2016-12-01

    Cell function is regulated by the spatiotemporal organization of the signaling machinery, and a key facet of this is molecular clustering. Here, we present a protocol for the analysis of clustering in data generated by 2D single-molecule localization microscopy (SMLM)-for example, photoactivated localization microscopy (PALM) or stochastic optical reconstruction microscopy (STORM). Three features of such data can cause standard cluster analysis approaches to be ineffective: (i) the data take the form of a list of points rather than a pixel array; (ii) there is a non-negligible unclustered background density of points that must be accounted for; and (iii) each localization has an associated uncertainty in regard to its position. These issues are overcome using a Bayesian, model-based approach. Many possible cluster configurations are proposed and scored against a generative model, which assumes Gaussian clusters overlaid on a completely spatially random (CSR) background, before every point is scrambled by its localization precision. We present the process of generating simulated and experimental data that are suitable to our algorithm, the analysis itself, and the extraction and interpretation of key cluster descriptors such as the number of clusters, cluster radii and the number of localizations per cluster. Variations in these descriptors can be interpreted as arising from changes in the organization of the cellular nanoarchitecture. The protocol requires no specific programming ability, and the processing time for one data set, typically containing 30 regions of interest, is ∼18 h; user input takes ∼1 h.

  17. Localized diabatization applied to excitons in molecular crystals

    DOE PAGES

    Jin, Zuxin; Subotnik, Joseph E.

    2017-06-28

    Traditional ab initio electronic structure calculations of periodic systems yield delocalized eigenstates that should be understood as adiabatic states. For example, excitons are bands of extended states which superimpose localized excitations on every lattice site. However, in general, in order to study the effects of nuclear motion on exciton transport, it is standard to work with a localized description of excitons, especially in a hopping regime; even in a band regime, a localized description can be helpful. To extract localized excitons from a band requires essentially a diabatization procedure. In this paper, three distinct methods are proposed for such localizedmore » diabatization: (i) a simple projection method, (ii) a more general Pipek-Mezey localization scheme, and (iii) a variant of Boys diabatization. Approaches (i) and (ii) require localized, single-particle Wannier orbitals, while approach (iii) has no such dependence. Lastly, these methods should be very useful for studying energy transfer through solids with ab initio calculations.« less

  18. Local quality functions for graph clustering with non-negative matrix factorization

    NASA Astrophysics Data System (ADS)

    van Laarhoven, Twan; Marchiori, Elena

    2014-12-01

    Many graph clustering quality functions suffer from a resolution limit, namely the inability to find small clusters in large graphs. So-called resolution-limit-free quality functions do not have this limit. This property was previously introduced for hard clustering, that is, graph partitioning. We investigate the resolution-limit-free property in the context of non-negative matrix factorization (NMF) for hard and soft graph clustering. To use NMF in the hard clustering setting, a common approach is to assign each node to its highest membership cluster. We show that in this case symmetric NMF is not resolution-limit free, but that it becomes so when hardness constraints are used as part of the optimization. The resulting function is strongly linked to the constant Potts model. In soft clustering, nodes can belong to more than one cluster, with varying degrees of membership. In this setting resolution-limit free turns out to be too strong a property. Therefore we introduce locality, which roughly states that changing one part of the graph does not affect the clustering of other parts of the graph. We argue that this is a desirable property, provide conditions under which NMF quality functions are local, and propose a novel class of local probabilistic NMF quality functions for soft graph clustering.

  19. Comments on "A robust fuzzy local information C-means clustering algorithm".

    PubMed

    Celik, Turgay; Lee, Hwee Kuan

    2013-03-01

    In a recent paper, Krinidis and Chatzis proposed a variation of fuzzy c-means algorithm for image clustering. The local spatial and gray-level information are incorporated in a fuzzy way through an energy function. The local minimizers of the designed energy function to obtain the fuzzy membership of each pixel and cluster centers are proposed. In this paper, it is shown that the local minimizers of Krinidis and Chatzis to obtain the fuzzy membership and the cluster centers in an iterative manner are not exclusively solutions for true local minimizers of their designed energy function. Thus, the local minimizers of Krinidis and Chatzis do not converge to the correct local minima of the designed energy function not because of tackling to the local minima, but because of the design of energy function.

  20. Typical medium dynamical cluster approximation for the study of Anderson localization in three dimensions

    NASA Astrophysics Data System (ADS)

    Ekuma, C. E.; Terletska, H.; Tam, K.-M.; Meng, Z.-Y.; Moreno, J.; Jarrell, M.

    2014-02-01

    We develop a systematic typical medium dynamical cluster approximation that provides a proper description of the Anderson localization transition in three dimensions (3D). Our method successfully captures the localization phenomenon both in the low and large disorder regimes, and allows us to study the localization in different momenta cells, which renders the discovery that the Anderson localization transition occurs in a cell-selective fashion. As a function of cluster size, our method systematically recovers the reentrance behavior of the mobility edge and obtains the correct critical disorder strength for Anderson localization in 3D.

  1. Input clustering and the microscale structure of local circuits

    PubMed Central

    DeBello, William M.; McBride, Thomas J.; Nichols, Grant S.; Pannoni, Katy E.; Sanculi, Daniel; Totten, Douglas J.

    2014-01-01

    The recent development of powerful tools for high-throughput mapping of synaptic networks promises major advances in understanding brain function. One open question is how circuits integrate and store information. Competing models based on random vs. structured connectivity make distinct predictions regarding the dendritic addressing of synaptic inputs. In this article we review recent experimental tests of one of these models, the input clustering hypothesis. Across circuits, brain regions and species, there is growing evidence of a link between synaptic co-activation and dendritic location, although this finding is not universal. The functional implications of input clustering and future challenges are discussed. PMID:25309336

  2. On-the-fly ab intito calculations of anharmonic vibrational frequencies: Local-monomer theory and application to HCl clusters

    NASA Astrophysics Data System (ADS)

    Mancini, John S.; Bowman, Joel M.

    2013-10-01

    We present an on-the-fly quantum mechanical method to obtain anharmonic vibrational frequencies for molecular clusters. The basis for the method is the local-monomer model, a "divide and conquer" approach to theoretical spectroscopy, previously applied using full-dimensional surfaces [Y. Wang and J. M. Bowman, J. Chem. Phys. 134, 154510 (2011)]. The model consists of performing a local normal-mode analysis for each monomer in a cluster in the field of the surrounding monomers. Anharmonic vibrational frequencies are then determined for each monomer by numerically solving the Schrödinger equation in terms of the local coordinates using ab initio energies obtained directly. Residual monomer-monomer coupling is accounted for using the Hückel-coupling extension [Y. Wang and J. M. Bowman, J. Chem. Phys. 136, 144113 (2012)]. In addition to the direct local-monomer approach, we propose and demonstrate a composite ab initio technique to reduce computational costs for calculating the anharmonic frequencies of large clusters. This technique utilizes two ab initio methods, a lower level of theory to compute geometries and perform harmonic analyses and a subsequent higher level of theory to compute the energies used in the anharmonic frequency calculations. We demonstrate the on-the-fly approach on hydrogen chloride clusters ranging in size from the dimer to the hexamer. Comparisons of the theoretical frequencies are made to previous experiments. We find the method to be an effective and computationally efficient approach to compute anharmonic frequencies.

  3. Effects of applied strain on nanoscale self-interstitial cluster formation in BCC iron

    NASA Astrophysics Data System (ADS)

    Gao, Ning; Setyawan, Wahyu; Kurtz, Richard J.; Wang, Zhiguang

    2017-09-01

    The effect of applied strains on the configurational evolution of self-interstitial clusters in BCC iron (Fe) is explored with atomistic simulations. A novel cluster configuration is discovered at low temperatures (<600 K), which consists of < 110 > dumbbells and < 111 > crowdions in a specific configuration, resulting in an immobile defect. The stability and diffusion of this cluster at higher temperatures is explored. In addition, an anisotropy distribution factor of a particular [ hkl ] interstitial loop within the family of < hkl > loops is calculated as a function of strain. The results show that loop anisotropy is governed by the angle between the stress direction and the orientation of the < 111 > crowdions in the loop, and directly linked to the stress induced preferred nucleation of self-interstitial atoms.

  4. Enhanced epidermal localization of topically applied steroids using SPACE™ peptide.

    PubMed

    Kumar, Sunny; Chen, Ming; Anselmo, Aaron C; Muraski, John A; Mitragotri, Samir

    2015-10-01

    The balance of efficacy and safety of topical corticosteroids (TCs) depends on their ability to penetrate into and be retained within the skin. Here, we evaluated the ability of SPACE™ peptide to enhance epidermal delivery and localization of three model TCs. In vitro and in vivo skin penetration studies were performed to evaluate penetration of TCs into and across the skin in the presence of various formulations of SPACE™ peptide. Topical formulations of corticosterone containing free SPACE™ peptide produced significantly enhanced epidermal penetration and localization. Ratio of drug deposition in the skin and receiver (efficacy/safety, indicative of ratio of local to systemic uptake) exhibited higher values for SPACE™ peptide-based formulation as compared to aqueous and hydroethanolic solutions and Cortizone™ cream. Mass spectrometry analysis showed that SPACE™ peptide associates with corticosterone, which may explain its enhanced retention effect. SPACE™ peptide also enhanced dermal retention of two more TCs (hydrocortisone and triamcinolone acetonide) compared to the vehicle control. An in vivo study in mice further established the ability of SPACE™ peptide to enhance skin retention of hydrocortisone without producing elevated blood concentrations. These results show that SPACE™ peptide is an effective additive to the formulation for enhanced skin localization of topical steroids.

  5. Applying Psychology in Local Authority Emergency Planning Processes

    ERIC Educational Resources Information Center

    Posada, Susan E.

    2006-01-01

    This article describes the work of two EPs involved in a multi-agency project to produce Local Authority (LA) guidelines on psycho/social support following critical incidents and disasters. EPs were involved as participant observers during a simulation of setting up and running a LA reception centre for evacuees. A questionnaire was then…

  6. Local-equilibrium formalism applied to mechanics of solids

    SciTech Connect

    Kestin, J.

    1992-08-01

    The lecture starts with an expression of good wishes to George Herrmann on the occasion of his seventieth birthday and continues with a lament that the majority of research workers in the field of solid mechanics have failed to appreciate the power and relevance of ``conventional`` thermodynamics which is based on the acceptance of the hypothesis of local equilibrium (principle of local state). The lecture then proceeds to motivate the essential concepts of conventional thermodynamics and emphasizes the differences between the description of nonequilibrium states in physical space and equilibrium states in the Gibbsian phase space. It is asserted that the subject acquires its simplest form by the recognition of the relevance of Bridgman`s internal variables. With their aid it is possible to define the accompanying equilibrium state and the accompanying reversible process. An elimination of internal energy between the field equation of energy (First Law) and the Gibbs equation in rate form results in an explicit expression for the local rate of entropy production, {theta}. It is asserted that the preceding elements supplemented with appropriate rate equations result in a closed system of partial differential equations whose solution, subject to appropriate initial and boundary conditions, constitutes the process (``history``) under consideration. 11 refs.

  7. Local-equilibrium formalism applied to mechanics of solids

    SciTech Connect

    Kestin, J.

    1992-01-01

    The lecture starts with an expression of good wishes to George Herrmann on the occasion of his seventieth birthday and continues with a lament that the majority of research workers in the field of solid mechanics have failed to appreciate the power and relevance of conventional'' thermodynamics which is based on the acceptance of the hypothesis of local equilibrium (principle of local state). The lecture then proceeds to motivate the essential concepts of conventional thermodynamics and emphasizes the differences between the description of nonequilibrium states in physical space and equilibrium states in the Gibbsian phase space. It is asserted that the subject acquires its simplest form by the recognition of the relevance of Bridgman's internal variables. With their aid it is possible to define the accompanying equilibrium state and the accompanying reversible process. An elimination of internal energy between the field equation of energy (First Law) and the Gibbs equation in rate form results in an explicit expression for the local rate of entropy production, {theta}. It is asserted that the preceding elements supplemented with appropriate rate equations result in a closed system of partial differential equations whose solution, subject to appropriate initial and boundary conditions, constitutes the process ( history'') under consideration. 11 refs.

  8. 20 CFR 666.300 - What performance indicators apply to local areas?

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 20 Employees' Benefits 3 2011-04-01 2011-04-01 false What performance indicators apply to local... Performance § 666.300 What performance indicators apply to local areas? (a) Each local workforce investment area in a State is subject to the same core indicators of performance and the customer...

  9. 20 CFR 666.300 - What performance indicators apply to local areas?

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 20 Employees' Benefits 3 2010-04-01 2010-04-01 false What performance indicators apply to local areas? 666.300 Section 666.300 Employees' Benefits EMPLOYMENT AND TRAINING ADMINISTRATION, DEPARTMENT OF... Performance § 666.300 What performance indicators apply to local areas? (a) Each local workforce...

  10. Airborne pollen in three European cities: Detection of atmospheric circulation pathways by applying three-dimensional clustering of backward trajectories

    NASA Astrophysics Data System (ADS)

    Makra, LáSzló; SáNta, TamáS.; Matyasovszky, IstváN.; Damialis, Athanasios; Karatzas, Kostas; Bergmann, Karl-Christian; Vokou, Despoina

    2010-12-01

    The long-range transport of particulates can substantially contribute to local air pollution. The importance of airborne pollen has grown due to the recent climate change; the lengthening of the pollen season and rising mean airborne pollen concentrations have increased health risks. Our aim is to identify atmospheric circulation pathways influencing pollen levels in three European cities, namely Thessaloniki, Szeged, and Hamburg. Trajectories were computed using the HYSPLIT model. The 4 day, 6 hourly three-dimensional (3-D) backward trajectories arriving at these locations at 1200 UT are produced for each day over a 5 year period. A k-means clustering algorithm using the Mahalanobis metric was applied in order to develop trajectory types. The delimitation of the clusters performed by the 3-D function "convhull" is a novel approach. The results of the cluster analysis reveal that the main pathways for Thessaloniki contributing substantially to the high mean Urticaceae pollen levels cover western Europe and the Mediterranean. The key pathway patterns for Ambrosia for Szeged are associated with backward trajectories coming from northwestern Europe, northeastern Europe, and northern Europe. A major pollen source identified is a cluster over central Europe, namely the Carpathian basin with peak values in Hungary. The principal patterns for Poaceae for Hamburg include western Europe and the mid-Atlantic region. Locations of the source areas coincide with the main habitat regions of the species in question. Critical daily pollen number exceedances conditioned on the clusters were also evaluated using two statistical indices. An attempt was made to separate medium- and long-range airborne pollen transport.

  11. The Hierarchical Distribution of the Young Stellar Clusters in Six Local Star-forming Galaxies

    NASA Astrophysics Data System (ADS)

    Grasha, K.; Calzetti, D.; Adamo, A.; Kim, H.; Elmegreen, B. G.; Gouliermis, D. A.; Dale, D. A.; Fumagalli, M.; Grebel, E. K.; Johnson, K. E.; Kahre, L.; Kennicutt, R. C.; Messa, M.; Pellerin, A.; Ryon, J. E.; Smith, L. J.; Shabani, F.; Thilker, D.; Ubeda, L.

    2017-05-01

    We present a study of the hierarchical clustering of the young stellar clusters in six local (3-15 Mpc) star-forming galaxies using Hubble Space Telescope broadband WFC3/UVIS UV and optical images from the Treasury Program LEGUS (Legacy ExtraGalactic UV Survey). We identified 3685 likely clusters and associations, each visually classified by their morphology, and we use the angular two-point correlation function to study the clustering of these stellar systems. We find that the spatial distribution of the young clusters and associations are clustered with respect to each other, forming large, unbound hierarchical star-forming complexes that are in general very young. The strength of the clustering decreases with increasing age of the star clusters and stellar associations, becoming more homogeneously distributed after ˜40-60 Myr and on scales larger than a few hundred parsecs. In all galaxies, the associations exhibit a global behavior that is distinct and more strongly correlated from compact clusters. Thus, populations of clusters are more evolved than associations in terms of their spatial distribution, traveling significantly from their birth site within a few tens of Myr, whereas associations show evidence of disruption occurring very quickly after their formation. The clustering of the stellar systems resembles that of a turbulent interstellar medium that drives the star formation process, correlating the components in unbound star-forming complexes in a hierarchical manner, dispersing shortly after formation, suggestive of a single, continuous mode of star formation across all galaxies.

  12. The Hyades cluster-supercluster connection - Evidence for a local concentration of dark matter

    NASA Technical Reports Server (NTRS)

    Casertano, Stefano; Iben, Icko, Jr.; Shiels, Aaron

    1993-01-01

    Stars that evaporate from the Hyades cluster will remain within a few hundred parsecs of the cluster only if they are dynamically bound to a much more massive entity containing the cluster. A local mass enhancement of at least (5-10) x 10 exp 5 solar masses, with a radius of about 100 pc, can trap stars with an origin related to that of the Hyades cluster and explains the excess of stars with velocities near the Hyades velocity that constitutes the Hyades supercluster. Part of this mass enhancement can be in visible stars, but a substantial fraction is likely to be in the form of dark matter.

  13. The Hyades cluster-supercluster connection - Evidence for a local concentration of dark matter

    NASA Technical Reports Server (NTRS)

    Casertano, Stefano; Iben, Icko, Jr.; Shiels, Aaron

    1993-01-01

    Stars that evaporate from the Hyades cluster will remain within a few hundred parsecs of the cluster only if they are dynamically bound to a much more massive entity containing the cluster. A local mass enhancement of at least (5-10) x 10 exp 5 solar masses, with a radius of about 100 pc, can trap stars with an origin related to that of the Hyades cluster and explains the excess of stars with velocities near the Hyades velocity that constitutes the Hyades supercluster. Part of this mass enhancement can be in visible stars, but a substantial fraction is likely to be in the form of dark matter.

  14. VizieR Online Data Catalog: OmegaWINGS local clusters of galaxies redshifts (Moretti+, 2017)

    NASA Astrophysics Data System (ADS)

    Moretti, A.; Gullieuszik, M.; Poggianti, B.; Paccagnella, A.; Couch, W. J.; Vulcani, B.; Bettoni, D.; Fritz, J.; Cava, A.; Fasaano, G.; D'Onofrio, M.; Omizzolo, A.

    2017-02-01

    Redshifts, magnitude/radial completeness, and memberships are given for the 17985 galaxies observed as part of the OmegaWINGS survey of local clusters of galaxies over 1 square degree. Redshifts have been measured using both absorption and emission lines features. The sample magnitude completeness is 80% at V=20. Thanks to the observing strategy, the radial completeness turned out to be relatively constant (90%) within the AAOmega field of view. The success rate in measuring redshifts is 95%, at all radii. Cluster members are flagged 1 or 2, depending on the cluster structure/secondary structure, and 0 if they are not cluster members. (1 data file).

  15. Clustering of giant virus-DNA based on variations in local entropy.

    PubMed

    Bose, Ranjan; Thiel, Gerhard; Hamacher, Kay

    2014-05-30

    We present a method for clustering genomic sequences based on variations in local entropy. We have analyzed the distributions of the block entropies of viruses and plant genomes. A distinct pattern for viruses and plant genomes is observed. These distributions, which describe the local entropic variability of the genomes, are used for clustering the genomes based on the Jensen-Shannon (JS) distances. The analysis of the JS distances between all genomes that infect the chlorella algae shows the host specificity of the viruses. We illustrate the efficacy of this entropy-based clustering technique by the segregation of plant and virus genomes into separate bins.

  16. Quantum-classical simulation of electron localization in negatively charged methanol clusters.

    PubMed

    Mones, Letif; Rossky, Peter J; Turi, László

    2011-08-28

    A series of quantum molecular dynamics simulations have been performed to investigate the energetic, structural, dynamic, and spectroscopic properties of methanol cluster anions, [(CH(3)OH)(n)](-), (n = 50-500). Consistent with the inference from photo-electron imaging experiments, we find two main localization modes of the excess electron in equilibrated methanol clusters at ∼200 K. The two different localization patterns have strikingly different physical properties, consistent with experimental observations, and are manifest in comparable cluster sizes to those observed. Smaller clusters (n ≤ 128) tend to localize the electron in very weakly bound, diffuse electronic states on the surface of the cluster, while in larger ones the electron is stabilized in solvent cavities, in compact interior-bound states. The interior states exhibit properties that largely resemble and smoothly extrapolate to those simulated for a solvated electron in bulk methanol. The surface electronic states of methanol cluster anions are significantly more weakly bound than the surface states of the anionic water clusters. The key source of the difference is the lack of stabilizing free hydroxyl groups on a relaxed methanol cluster surface. We also provide a mechanistic picture that illustrates the essential role of the interactions of the excess electron with the hydroxyl groups in the dynamic process of the transition of the electron from surface-bound states to interior-bound states.

  17. Southern Sky Redshift Survey: Clustering of Local Galaxies

    NASA Astrophysics Data System (ADS)

    Willmer, Christopher N. A.; da Costa, Luiz Nicolaci; Pellegrini, Paulo S.

    1998-03-01

    We use the two-point correlation function to calculate the clustering properties of the recently completed SSRS2 survey, which probes two well-separated regions of the sky, allowing one to evaluate the sensitivity of sample-to-sample variations. Taking advantage of the large number of galaxies in the combined sample, we also investigate the dependence of clustering on the internal properties of galaxies. The redshift-space correlation function for the combined magnitude-limited sample of the SSRS2 is given by xi(s) = [s/(5.85 h^-1 Mpc)]^-1.60 for separations in the range 2 h^-1 Mpc <= s <= 11 h^-1 Mpc, while our best estimate for the real-space correlation function is xi(r) = [r/(5.36 h^-1 Mpc)]^-1.86. Both are comparable with previous measurements using surveys of optical galaxies over much larger and independent volumes. By comparing the correlation function calculated in redshift and real space, we find that the redshift distortion on intermediate scales is small. This result implies that the observed redshift-space distribution of galaxies is close to that in real space and that beta = Omega^0.6/b < 1, where Omega is the cosmological density parameter and b is the linear biasing factor for optical galaxies. We have used the SSRS2 sample to study the dependence of xi on the internal properties of galaxies, such as luminosity, morphology, and color. We confirm earlier results that luminous galaxies (L > L^*) are more clustered than sub-L^* galaxies and that the luminosity segregation is scale-independent. We also find that early types are more clustered than late types. However, in the absence of rich clusters, the relative bias between early and late types in real space, b_E+S0/b_S ~ 1.2, is not as strong as previously estimated. Furthermore, both morphologies present a luminosity-dependent bias, with the early types showing a slightly stronger dependence on luminosity. We also find that red galaxies are significantly more clustered than blue ones, with a mean

  18. Comparison of Local Information Indices Applied in Resting State Functional Brain Network Connectivity Prediction

    PubMed Central

    Cheng, Chen; Chen, Junjie; Cao, Xiaohua; Guo, Hao

    2016-01-01

    Anatomical distance has been widely used to predict functional connectivity because of the potential relationship between structural connectivity and functional connectivity. The basic implicit assumption of this method is “distance penalization.” But studies have shown that one-parameter model (anatomical distance) cannot account for the small-worldness, modularity, and degree distribution of normal human brain functional networks. Two local information indices–common neighbor (CN) and preferential attachment index (PA), are introduced into the prediction model as another parameter to emulate many key topological of brain functional networks in the previous study. In addition to these two indices, many other local information indices can be chosen for investigation. Different indices evaluate local similarity from different perspectives. Currently, we still have no idea about how to select local information indices to achieve higher predicted accuracy of functional connectivity. Here, seven local information indices are chosen, including CN, hub depressed index (HDI), hub promoted index (HPI), Leicht-Holme-Newman index (LHN-I), Sørensen index (SI), PA, and resource allocation index (RA). Statistical analyses were performed on eight network topological properties to evaluate the predictions. Analysis shows that different prediction models have different performances in terms of simulating topological properties and most of the predicted network properties are close to the real data. There are four topological properties whose average relative error is less than 5%, including characteristic path length, clustering coefficient, global efficiency, and local efficiency. CN model shows the most accurate predictions. Statistical analysis reveals that five properties within the CN-predicted network do not differ significantly from the real data (P > 0.05, false-discovery rate method corrected for seven comparisons). PA model shows the worst prediction performance

  19. Markov random field-based clustering applied to the segmentation of masses in digital mammograms.

    PubMed

    Suliga, M; Deklerck, R; Nyssen, E

    2008-09-01

    In this paper we propose a new pixel clustering model applied to the analysis of digital mammograms. The clustering represents here the first step in a more general method and aims at the creation of a concise data-set (clusters) for automatic detection and classification of masses, which are typically among the first symptoms analysed in early diagnosis of breast cancer. For the purpose of this work, a set of mammographic images has been employed, that are 12-bit gray level digital scans and as such, are inherently inhomogeneous and affected by the noise resulting from the film scanning. The image pixels are described only by their intensity (gray level), therefore, the available information is limited to one dimension. We propose a Markov random field (MRF)-based technique that is suitable for performing clustering in an environment which is described by poor or limited data. The proposed method is a statistical classification model, that labels the image pixels based on the description of their statistical and contextual information. Apart from evaluating the pixel statistics, that originate from the definition of the K-means clustering scheme, the model expands the analysis by the description of the spatial dependence between pixels and their labels (context), hence leading to the reduction of the inhomogeneity of the output. Moreover, we define a probabilistic description of the model, that is characterised by a remarkable simplicity, such that its realisation can be easily and efficiently implemented in any high- or low-level programming language, thus allowing it to be run on virtually any kind of platform. Finally, we evaluate the algorithm against the classical K-means clustering routine. We point out similarities between the two methods and, moreover, show the advantages and superiority of the MRF scheme.

  20. Study of Semiconductor Clusters by Local Inverse Photo Emission

    DTIC Science & Technology

    1991-01-01

    00511 91 5 24 0’ 5 IU!tl/H~illi~~ STM Publications Semiconductors and Surfaces Dror Sarid , Brian P. McGinnis, and Tammy D. Henson, "Four-wave mixing...Los Angeles 10-17 January (1988). Dror Sarid , Tammy D. Henson, L. Stephen Bell, and Claude J. Sandroff, "Scanning tunneling microscopy of semiconductor...clusters,"J. Vac. Sci. and Tech. A 6, 424 (1988). Dror Sarid , Tammy D. Henson, Neal Armstrong, and L. Stephen Bell, "Probing of Basal Planes of MoS 2

  1. In Situ Characterization of Bak Clusters Responsible for Cell Death Using Single Molecule Localization Microscopy

    PubMed Central

    Nasu, Yusuke; Benke, Alexander; Arakawa, Satoko; Yoshida, Go J.; Kawamura, Genki; Manley, Suliana; Shimizu, Shigeomi; Ozawa, Takeaki

    2016-01-01

    Apoptosis plays a pivotal role in development and tissue homeostasis in multicellular organisms. Clustering of Bak proteins on the mitochondrial outer membrane is responsible for the induction of apoptosis by evoking a release of pro-apoptotic proteins from mitochondria into cytosol. However, how the protein cluster permeabilizes the mitochondrial membrane remains unclear because elucidation of the cluster characteristics such as size and protein density has been hampered by the diffraction-limited resolution of light microscopy. Here, we describe an approach to quantitatively characterize Bak clusters in situ based on single molecule localization. We showed that Bak proteins form densely packed clusters at the nanoscale on mitochondria during apoptosis. Quantitative analysis based on the localization of each Bak protein revealed that the density of Bak protein is uniform among clusters although the cluster size is highly heterogeneous. Our approach provides unprecedented information on the size and protein density of Bak clusters possibly critical for the permeabilization and is applicable for the analysis of different cluster formations. PMID:27293178

  2. Adaptive partitioning by local density-peaks: An efficient density-based clustering algorithm for analyzing molecular dynamics trajectories.

    PubMed

    Liu, Song; Zhu, Lizhe; Sheong, Fu Kit; Wang, Wei; Huang, Xuhui

    2017-01-30

    We present an efficient density-based adaptive-resolution clustering method APLoD for analyzing large-scale molecular dynamics (MD) trajectories. APLoD performs the k-nearest-neighbors search to estimate the density of MD conformations in a local fashion, which can group MD conformations in the same high-density region into a cluster. APLoD greatly improves the popular density peaks algorithm by reducing the running time and the memory usage by 2-3 orders of magnitude for systems ranging from alanine dipeptide to a 370-residue Maltose-binding protein. In addition, we demonstrate that APLoD can produce clusters with various sizes that are adaptive to the underlying density (i.e., larger clusters at low-density regions, while smaller clusters at high-density regions), which is a clear advantage over other popular clustering algorithms including k-centers and k-medoids. We anticipate that APLoD can be widely applied to split ultra-large MD datasets containing millions of conformations for subsequent construction of Markov State Models. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  3. Alignments of the galaxies in and around the Virgo cluster with the local velocity shear

    SciTech Connect

    Lee, Jounghun; Rey, Soo Chang; Kim, Suk

    2014-08-10

    Observational evidence is presented for the alignment between the cosmic sheet and the principal axis of the velocity shear field at the position of the Virgo cluster. The galaxies in and around the Virgo cluster from the Extended Virgo Cluster Catalog that was recently constructed by Kim et al. are used to determine the direction of the local sheet. The peculiar velocity field reconstructed from the Sloan Digital Sky Survey Data Release 7 is analyzed to estimate the local velocity shear tensor at the Virgo center. Showing first that the minor principal axis of the local velocity shear tensor is almost parallel to the direction of the line of sight, we detect a clear signal of alignment between the positions of the Virgo satellites and the intermediate principal axis of the local velocity shear projected onto the plane of the sky. Furthermore, the dwarf satellites are found to appear more strongly aligned than their normal counterparts, which is interpreted as an indication of the following. (1) The normal satellites and the dwarf satellites fall in the Virgo cluster preferentially along the local filament and the local sheet, respectively. (2) The local filament is aligned with the minor principal axis of the local velocity shear while the local sheet is parallel to the plane spanned by the minor and intermediate principal axes. Our result is consistent with the recent numerical claim that the velocity shear is a good tracer of the cosmic web.

  4. Ages of Globular Clusters from HIPPARCOS Parallaxes of Local Subdwarfs

    NASA Astrophysics Data System (ADS)

    Gratton, Raffaele G.; Fusi Pecci, Flavio; Carretta, Eugenio; Clementini, Gisella; Corsi, Carlo E.; Lattanzi, Mario

    1997-12-01

    We report here initial but strongly conclusive results for absolute ages of Galactic globular clusters (GGCs). This study is based on high-precision trigonometric parallaxes from the HIPPARCOS satellite coupled with accurate metal abundances ([Fe/H], [O/Fe], and [α/Fe]) from high-resolution spectroscopy for a sample of about thirty subdwarfs. Systematic effects due to star selection (Lutz-Kelker corrections to parallaxes) and the possible presence of undetected binaries in the sample of bona fide single stars are examined, and appropriate corrections are estimated. They are found to be small for our sample. The new data allow us to reliably define the absolute location of the main sequence (MS) as a function of metallicity. These results are then used to derive distances and ages for a carefully selected sample of nine globular clusters having metallicities determined from high-dispersion spectra of individual giants according to a procedure totally consistent with that used for the field subdwarfs. Very precise and homogeneous reddening values have also been independently determined for these clusters. Random errors for our distance moduli are +/-0.08 mag, and systematic errors are likely of the same order of magnitude. These very accurate distances allow us to derive ages with internal errors of ~12% (+/-1.5 Gyr). The main results are: 1. HIPPARCOS parallaxes are smaller than corresponding ground-based measurements, leading, in turn, to longer distance moduli (~0.2 mag) and younger ages (~2.8 Gyr). 2. The distance to NGC 6752 derived from our MS fitting is consistent with that determined using the white dwarf cooling sequence. 3. The relation between the zero-age HB (ZAHB) absolute magnitude and metallicity for the nine program clusters is MV(ZAHB)=(0.22+/-0.09)([Fe/H]+1.5)+(0.49+/-0.04) . This relation is fairly consistent with some of the most recent theoretical models. Within quoted errors, the slope is in agreement with that given by the Baade-Wesselink (BW

  5. Quantitative analysis of individual hepatocyte growth factor receptor clusters in influenza A virus infected human epithelial cells using localization microscopy.

    PubMed

    Wang, Qiaoyun; Dierkes, Rüdiger; Kaufmann, Rainer; Cremer, Christoph

    2014-04-01

    In this report, we applied a special localization microscopy technique (Spectral Precision Distance/Spatial Position Determination Microscopy/SPDM) to quantitatively analyze the effect of influenza A virus (IAV) infection on the spatial distribution of individual HGFR (Hepatocyte Growth Factor Receptor) proteins on the membrane of human epithelial cells at the single molecule resolution level. We applied this SPDM method to Alexa 488 labeled HGFR proteins with two different ligands. The ligands were either HGF (Hepatocyte Growth Factor), or IAV. In addition, the HGFR distribution in a control group of mock-incubated cells without any ligands was investigated. The spatial distribution of 1×10(6) individual HGFR proteins localized in large regions of interest on membranes of 240 cells was quantitatively analyzed and found to be highly non-random. Between 21% and 24% of the HGFR molecules were located in 44,304 small clusters with an average diameter of 54nm. The mean density of HGFR molecule signals per individual cluster was very similar in control cells, in cells with ligand only, and in IAV infected cells, independent of the incubation time. From the density of HGFR molecule signals in the clusters and the diameter of the clusters, the number of HGFR molecule signals per cluster was estimated to be in the range between 4 and 11 (means 5-6). This suggests that the membrane bound HGFR clusters form small molecular complexes with a maximum diameter of few tens of nm, composed of a relatively low number of HGFR molecules. This article is part of a Special Issue entitled: Viral Membrane Proteins - Channels for Cellular Networking. Copyright © 2013 Elsevier B.V. All rights reserved.

  6. Evolution of Local Microstructures: Spatial Instabilities of Coarsening Clusters

    NASA Technical Reports Server (NTRS)

    Frazier, Donald O.

    1999-01-01

    dynamics at various volume fractions. Preliminary results of numerical and experimental investigations, focused on the growth of finite particle clusters, provide important insight into the nature of the transition between the two scaling regimes. The companion microgravity experiment centers on the growth within finite particle clusters, and follows the temporal dynamics driving microstructural evolution, using holography.

  7. Study of semiconductor clusters by local inverse photo emission

    NASA Astrophysics Data System (ADS)

    Sarid, Dror

    The project of building the first system consisting of a scanning tunneling microscope operating in ultra-high vacuum is completed, and all the components are now operational. STM images of charge-density waves in UHV were successfully obtained. Two other systems were developed and operated that enable performance of the task delineated in the original ONR proposal. The second system is a computerized nanolithography station where computer generated patterns drive the STM tip, which deposits atoms at the pre-prescribed locations. The third system measures the photon emission from nanostructures using a cooled photomultiplier, a photon counter, and an image processor. Several papers are currently being written that describe the theory of photon emission from STM-deposited patterns and the various experiments performed with these three systems. Enclosed is a list of publications describing our STM work. Future plans call for the refinement of the experiments where clusters are written and their light emission recorded and analyzed topographically and spectroscopically.

  8. The inhomogeneous reionization of the local intergalactic medium by metal-poor globular clusters

    NASA Astrophysics Data System (ADS)

    Griffen, B. F.; Drinkwater, M. J.; Iliev, Ilian T.; Thomas, P. A.; Mellema, Garrelt

    2013-06-01

    We present detailed radiative transfer simulations of the reionization of the Milky Way by metal-poor globular clusters. We identify potential metal-poor globular cluster candidates within the Aquarius simulation using dark matter halo velocity dispersions. We calculate the local ionization fields via a photon-conserving, three dimensional non-equilibrium chemistry code. The key feature of the model is that globular cluster formation is suppressed if the local gas is ionized. We assume that at these early times, the ionization field is dominated by the flux from metal-poor globular clusters. Our spatial treatment of the ionization field leads to drastically different numbers and spatial distributions when compared to models where globular cluster formation is simply truncated at early redshifts (z ˜ 13). The spatial distributions are more extended and more globular clusters are produced. We find that additional sources of ionization are required at later epochs (z ˜ 10) to ionize the remaining gas and recover radial distributions statistically consistent with that of the Milky Way metal-poor globular clusters. We investigate a range of plausible ionization efficiencies to determine the effect photon-rich and photon-poor models have on present-day globular cluster properties. If globular clusters do indeed form within high-redshift dark matter haloes, they produce enough photons to ionize 98 and 90 per cent local (i.e. 23 h-3 Mpc3 centred on the host galaxy) volume and mass by redshift 10, respectively. In our photon-poorest model, this contribution drops to 60 and 50 per cent. Our model therefore implies that globular clusters are important contributors to the reionization process on local scales at high-redshift until more photon-rich sources dominate the photon budget at later times. The surviving clusters in all models have a narrow average age range (mean = 13.34 Gyr, σ = 0.04 Gyr) consistent with current age estimates of the Milky Way metal-poor globular

  9. 3D localization of clustered microcalcifications using cranio-caudal and medio-lateral oblique views.

    PubMed

    Yang, Sheng-Chih; Hsu, Hsian-He; Hsu, Giu-Cheng; Chung, Pau-Choo; Guo, Shu-Mei; Lo, Chien-Shen; Yang, Ching-Wen; Lee, San-Kan; Chang, Chein-I

    2005-10-01

    This paper presents a 3D localization method to register clustered microcalcifications on mammograms from cranio-caudal (CC) and medio-lateral oblique (MLO) views. The method consists of three major components: registration of clustered microcalcifications in CC and MLO views, 3D localization of clustered microcalcifications and 3D visualization of clustered microcalcifications. The registration is performed based on three features, gradient, energy and local entropy codes that are independent of spatial locations of microcalcifications in two different views and are prioritized by discriminability in a binary decision tree. The 3D localization is determined by a sequence of coordinate corrections of calcified pixels using the breast nipple as a controlling point. Finally, the 3D visualization implements a virtual reality modeling language viewer (VRMLV) to view the exact location of the lesion as a guide for needle biopsy. In order to validate our proposed 3D localization system, a set of breast lesions, which appear both in mammograms and in MR Images is used for experiments where the depth of clustered microcalcifications can be verified by the MR images.

  10. 20 CFR 666.300 - What performance indicators apply to local areas?

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 20 Employees' Benefits 4 2014-04-01 2014-04-01 false What performance indicators apply to local areas? 666.300 Section 666.300 Employees' Benefits EMPLOYMENT AND TRAINING ADMINISTRATION, DEPARTMENT OF... Measures of Performance § 666.300 What performance indicators apply to local areas? (a) Each...

  11. Clustering by fast search and merge of local density peaks for gene expression microarray data.

    PubMed

    Mehmood, Rashid; El-Ashram, Saeed; Bie, Rongfang; Dawood, Hussain; Kos, Anton

    2017-04-19

    Clustering is an unsupervised approach to classify elements based on their similarity, and it is used to find the intrinsic patterns of data. There are enormous applications of clustering in bioinformatics, pattern recognition, and astronomy. This paper presents a clustering approach based on the idea that density wise single or multiple connected regions make a cluster, in which density maxima point represents the center of the corresponding density region. More precisely, our approach firstly finds the local density regions and subsequently merges the density connected regions to form the meaningful clusters. This idea empowers the clustering procedure, in which outliers are automatically detected, higher dense regions are intuitively determined and merged to form clusters of arbitrary shape, and clusters are identified regardless the dimensionality of space in which they are embedded. Extensive experiments are performed on several complex data sets to analyze and compare our approach with the state-of-the-art clustering methods. In addition, we benchmarked the algorithm on gene expression microarray data sets for cancer subtyping; to distinguish normal tissues from tumor; and to classify multiple tissue data sets.

  12. Clustering by fast search and merge of local density peaks for gene expression microarray data

    PubMed Central

    Mehmood, Rashid; El-Ashram, Saeed; Bie, Rongfang; Dawood, Hussain; Kos, Anton

    2017-01-01

    Clustering is an unsupervised approach to classify elements based on their similarity, and it is used to find the intrinsic patterns of data. There are enormous applications of clustering in bioinformatics, pattern recognition, and astronomy. This paper presents a clustering approach based on the idea that density wise single or multiple connected regions make a cluster, in which density maxima point represents the center of the corresponding density region. More precisely, our approach firstly finds the local density regions and subsequently merges the density connected regions to form the meaningful clusters. This idea empowers the clustering procedure, in which outliers are automatically detected, higher dense regions are intuitively determined and merged to form clusters of arbitrary shape, and clusters are identified regardless the dimensionality of space in which they are embedded. Extensive experiments are performed on several complex data sets to analyze and compare our approach with the state-of-the-art clustering methods. In addition, we benchmarked the algorithm on gene expression microarray data sets for cancer subtyping; to distinguish normal tissues from tumor; and to classify multiple tissue data sets. PMID:28422088

  13. Cooperation between the products of different nuclei in hybrid myotubes produces localized acetylcholine receptor clusters.

    PubMed Central

    Gordon, H; Ralston, E; Hall, Z W

    1992-01-01

    Cultured myotubes form clusters of acetylcholine receptors (AChRs) spontaneously and at sites of nerve-muscle contact. To investigate the cellular mechanisms by which spontaneous clusters are formed, we have made hybrid myotubes between a mouse muscle cell variant, S27, that does not cluster AChRs, and one that does not make AChRs. We have also made hybrid myotubes using S27 and quail muscle cells. In both cases, clusters of AChRs were found near the non-S27 nuclei; in the case of the interspecific hybrids, mouse AChRs were associated with extracellular matrix components contributed by the quail nuclei. Our results suggest that AChRs made by one nucleus can be clustered by localized extracellular matrix produced by a different nucleus and provide an example of nuclear cooperation between the products of different nuclei within multinucleated muscle fibers. Images PMID:1631161

  14. An analysis of the optimal multiobjective inventory clustering decision with small quantity and great variety inventory by applying a DPSO.

    PubMed

    Wang, Shen-Tsu; Li, Meng-Hua

    2014-01-01

    When an enterprise has thousands of varieties in its inventory, the use of a single management method could not be a feasible approach. A better way to manage this problem would be to categorise inventory items into several clusters according to inventory decisions and to use different management methods for managing different clusters. The present study applies DPSO (dynamic particle swarm optimisation) to a problem of clustering of inventory items. Without the requirement of prior inventory knowledge, inventory items are automatically clustered into near optimal clustering number. The obtained clustering results should satisfy the inventory objective equation, which consists of different objectives such as total cost, backorder rate, demand relevance, and inventory turnover rate. This study integrates the above four objectives into a multiobjective equation, and inputs the actual inventory items of the enterprise into DPSO. In comparison with other clustering methods, the proposed method can consider different objectives and obtain an overall better solution to obtain better convergence results and inventory decisions.

  15. Genomic rearrangements and the evolution of clusters of locally adaptive loci

    PubMed Central

    Yeaman, Sam

    2013-01-01

    Numerous studies of ecological genetics have found that alleles contributing to local adaptation sometimes cluster together, forming “genomic islands of divergence.” Divergence hitchhiking theory posits that these clusters evolve by the preferential establishment of tightly linked locally adapted mutations, because such linkage reduces the rate that recombination breaks up locally favorable combinations of alleles. Here, I use calculations based on previously developed analytical models of divergence hitchhiking to show that very few clustered mutations should be expected in a single bout of adaptation, relative to the number of unlinked mutations, suggesting that divergence hitchhiking theory alone may often be insufficient to explain empirical observations. Using individual-based simulations that allow for the transposition of a single genetic locus from one position on a chromosome to another, I then show that tight clustering of the loci involved in local adaptation tends to evolve on biologically realistic time scales. These results suggest that genomic rearrangements may often be an important component of local adaptation and the evolution of genomic islands of divergence. More generally, these results suggest that genomic architecture and functional neighborhoods of genes may be actively shaped by natural selection in heterogeneous environments. Because small-scale changes in gene order are relatively common in some taxa, comparative genomic studies could be coupled with studies of adaptation to explore how commonly such rearrangements are involved in local adaptation. PMID:23610436

  16. Applying Mean-Shift - Clustering for 3D object detection in remote sensing data

    NASA Astrophysics Data System (ADS)

    Simon, Jürgen-Lorenz; Diederich, Malte; Troemel, Silke

    2013-04-01

    The timely warning and forecasting of high-impact weather events is crucial for life, safety and economy. Therefore, the development and improvement of methods for detection and nowcasting / short-term forecasting of these events is an ongoing research question. A new 3D object detection and tracking algorithm is presented. Within the project "object-based analysis and seamless predictin (OASE)" we address a better understanding and forecasting of convective events based on the synergetic use of remotely sensed data and new methods for detection, nowcasting, validation and assimilation. In order to gain advanced insight into the lifecycle of convective cells, we perform an object-detection on a new high-resolution 3D radar- and satellite based composite and plan to track the detected objects over time, providing us with a model of the lifecycle. The insights in the lifecycle will be used in order to improve prediction of convective events in the nowcasting time scale, as well as a new type of data to be assimilated into numerical weather models, thus seamlessly bridging the gap between nowcasting and NWP.. The object identification (or clustering) is performed using a technique borrowed from computer vision, called mean-shift clustering. Mean-Shift clustering works without many of the parameterizations or rigid threshold schemes employed by many existing schemes (e. g. KONRAD, TITAN, Trace-3D), which limit the tracking to fully matured, convective cells of significant size and/or strength. Mean-Shift performs without such limiting definitions, providing a wider scope for studying larger classes of phenomena and providing a vehicle for research into the object definition itself. Since the mean-shift clustering technique could be applied on many types of remote-sensing and model data for object detection, it is of general interest to the remote sensing and modeling community. The focus of the presentation is the introduction of this technique and the results of its

  17. Fingerprint-based clustering applied to define a QSAR model use radius.

    PubMed

    Sprous, D G

    2008-09-01

    In ongoing research, QSAR has been a tool applied to evaluate compound qualities associated with skin permeability and membership in either a druglike class or specific nondruglike type classes. A need that arose from this pursuit was to know the boundaries of the QSAR models within which molecules could be analyzed. To satisfy this need, a method of QSAR model validation was developed which moves away from the simple declaration of correlation to a description of expected correlation as a function of similarity to the training set. This extension of the "validation" and "predictive" concepts to include a border is referred to henceforth as the QSAR model use radius. By defining this metric, it is possible to select for models which have predictivity exterior to their training sets. The heart of this approach is the common use of division into training sets and test sets to demonstrate an ability to successfully predict outside of the training set. The new rigor introduced is to repetitively cluster and systematically increase the permitted dissimilarity within those clusters. The training sets are assembled by taking one and only one compound from each cluster at a specific level of permitted dissimilarity. The QSAR model is developed over these training sets and applied to predict the remaining compounds. In this manner, it is possible to point where there is adequate similarity to predict a compound and where there is not. This method is especially useful for large, chemically redundant systems of greater than 250 compounds where leave-one-out crossvalidation is of limited use. To illustrate this technique, the results of defining the use radius for (a) a skin permeability model (based on 276 compounds), (b) a drug compound and "safe" compound partition (3000 compounds) and (c) a kinase inhibitor and drug compound partition ( approximately 1300 compounds) are discussed.

  18. Localized Surface Plasmon Resonance properties of copper nano-clusters: A theoretical study of size dependence

    NASA Astrophysics Data System (ADS)

    Ziashahabi, A.; Ghodselahi, T.; Heidari saani, M.

    2013-07-01

    Density functional theory (DFT) calculations are carried out to study the electronic, structural stability and Localized Surface Plasmon Resonance (LSPR) properties of copper nano-clusters. These nano-clusters consisted of 14, 38, 62 and 116 atoms. We studied surface charge density and interband-transitions effects on damping and broadening of the surface plasmon resonance absorption spectra. An enhancement in interband-transition energy and a reduction in surface charge density with decrease in the size of clusters are observed. These features result in the damping and broadening of the LSPR absorption spectra. We also study the structural stability and HOMO-LUMO energy gap of copper clusters. The structural stability of nano-clusters reduces by decreasing the size of the clusters. The HOMO-LUMO energy gap is not zero for the clusters with size less than 2 nm which indicates the lack of conduction electrons which are necessary for LSPR absorption. The calculated interband transition energies are in agreement with LSPR absorption data. We also discuss the difference between size dependent LSPR in copper and gold nano-clusters in the experiment based on calculated surface charge density.

  19. Local Spatial Clustering in Youths Use of Tobacco, Alcohol and Marijuana in Boston, Massachusetts, USA

    PubMed Central

    Duncan, Dustin T.; Rienti, Michael; Kulldorff, Martin; Aldstadt, Jared; Castro, Marcia C.; Frounfelker, Rochelle; Williams, James H.; Sorensen, Glorian; Johnson, Renee M.; Hemenway, David; Williams, David R.

    2016-01-01

    Background Understanding geographic variation in youth drug use is important for both identifying etiologic factors and planning prevention interventions. However, little research has examined spatial clustering of drug use among youth using rigorous statistical methods. Objectives The purpose of this study is to examine spatial clustering of youth use of tobacco, alcohol, and marijuana. Methods Responses on tobacco, alcohol, and marijuana use from 1,292 high school students ages 13-19 who provided complete residential addresses were drawn from the 2008 Boston Youth Survey Geospatial Dataset. Response options on past month use included “none”, “1-2”, “3-9”, and “10 or more”. The response rate for each substance was approximately 94%. Spatial clustering of youth drug use was assessed using the spatial Bernoulli model in the SatScan™ software package. Results Approximately 12%, 36%, and 18% of youth reported any past-month use of tobacco, alcohol, and/or marijuana, respectively. Two clusters of elevated past tobacco use among Boston youths were generated, one of which was statistically significant. This cluster, located in the South Boston neighborhood, had a relative risk of 5.37 with a p-value of 0.00014. There was no significant localized spatial clustering in youth past alcohol or marijuana use in either the unadjusted or adjusted models. Conclusion Significant spatial clustering in youth tobacco use was found, and this type of research can be used for local targeting of drug abuse prevention interventions. Finding a significant cluster in the South Boston neighborhood provides reason for further investigation into neighborhood characteristics that may shape adolescents’ substance use behaviors. Future research should evaluate the underlying reasons behind spatial clustering of youth substance use. PMID:27096932

  20. Abundances of Local Group Globular Clusters Using High Resolution Integrated Light Spectroscopy

    NASA Astrophysics Data System (ADS)

    Sakari, Charli; McWilliam, A.; Venn, K.; Shetrone, M. D.; Dotter, A. L.; Mackey, D.

    2014-01-01

    Abundances and kinematics of extragalactic globular clusters provide valuable clues about galaxy and globular cluster formation in a wide variety of environments. In order to obtain such information about distant, unresolved systems, specific observational techniques are required. An Integrated Light Spectrum (ILS) provides a single spectrum from an entire stellar population, and can therefore be used to determine integrated cluster abundances. This dissertation investigates the accuracy of high resolution ILS analysis methods, using ILS (taken with the Hobby-Eberly Telescope) of globular clusters associated with the Milky Way (47 Tuc, M3, M13, NGC 7006, and M15) and then applies the method to globular clusters in the outer halo of M31 (from the Pan-Andromeda Archaeological Survey, or PAndAS). Results show that: a) as expected, the high resolution method reproduces individual stellar abundances for elements that do not vary within a cluster; b) the presence of multiple populations does affect the abundances of elements that vary within the cluster; c) certain abundance ratios are very sensitive to systematic effects, while others are not; and d) certain abundance ratios (e.g. [Ca/Fe]) can be accurately obtained from unresolved systems. Applications of ILABUNDS to the PAndAS clusters reveal that accretion may have played an important role in the formation of M31's outer halo.

  1. WINGS-SPE. III. Equivalent width measurements, spectral properties, and evolution of local cluster galaxies

    NASA Astrophysics Data System (ADS)

    Fritz, J.; Poggianti, B. M.; Cava, A.; Moretti, A.; Varela, J.; Bettoni, D.; Couch, W. J.; D'Onofrio D'Onofrio, M.; Dressler, A.; Fasano, G.; Kjærgaard, P.; Marziani, P.; Moles, M.; Omizzolo, A.

    2014-06-01

    Context. Cluster galaxies are the ideal sites to look at when studying the influence of the environment on the various aspects of the evolution of galaxies, such as the changes in their stellar content and morphological transformations. In the framework of wings, the WIde-field Nearby Galaxy-cluster Survey, we have obtained optical spectra for ~6000 galaxies selected in fields centred on 48 local (0.04 < z < 0.07) X-ray selected clusters to tackle these issues. Aims: By classifying the spectra based on given spectral lines, we investigate the frequency of the various spectral types as a function of both the clusters' properties and the galaxies' characteristics. In this way, using the same classification criteria adopted for studies at higher redshift, we can consistently compare the properties of the local cluster population to those of their more distant counterparts. Methods: We describe a method that we have developed to automatically measure the equivalent width of spectral lines in a robust way, even in spectra with a non optimal signal-to-noise ratio. This way, we can derive a spectral classification reflecting the stellar content, based on the presence and strength of the [Oii] and Hδ lines. Results: After a quality check, we are able to measure 4381 of the ~6000 originally observed spectra in the fields of 48 clusters, of which 2744 are spectroscopically confirmed cluster members. The spectral classification is then analysed as a function of galaxies' luminosity, stellar mass, morphology, local density, and host cluster's global properties and compared to higher redshift samples (MORPHS and EDisCS). The vast majority of galaxies in the local clusters population are passive objects, being also the most luminous and massive. At a magnitude limit of MV < -18, galaxies in a post-starburst phase represent only ~11% of the cluster population, and this fraction is reduced to ~5% at MV < -19.5, which compares to the 18% at the same magnitude limit for high

  2. Order statistics applied to the most massive and most distant galaxy clusters

    NASA Astrophysics Data System (ADS)

    Waizmann, J.-C.; Ettori, S.; Bartelmann, M.

    2013-06-01

    In this work, we present an analytic framework for calculating the individual and joint distributions of the nth most massive or nth highest redshift galaxy cluster for a given survey characteristic allowing us to formulate Λ cold dark matter (ΛCDM) exclusion criteria. We show that the cumulative distribution functions steepen with increasing order, giving them a higher constraining power with respect to the extreme value statistics. Additionally, we find that the order statistics in mass (being dominated by clusters at lower redshifts) is sensitive to the matter density and the normalization of the matter fluctuations, whereas the order statistics in redshift is particularly sensitive to the geometric evolution of the Universe. For a fixed cosmology, both order statistics are efficient probes of the functional shape of the mass function at the high-mass end. To allow a quick assessment of both order statistics, we provide fits as a function of the survey area that allow percentile estimation with an accuracy better than 2 per cent. Furthermore, we discuss the joint distributions in the two-dimensional case and find that for the combination of the largest and the second largest observation, it is most likely to find them to be realized with similar values with a broadly peaked distribution. When combining the largest observation with higher orders, it is more likely to find a larger gap between the observations and when combining higher orders in general, the joint probability density function peaks more strongly. Having introduced the theory, we apply the order statistical analysis to the Southpole Telescope (SPT) massive cluster sample and metacatalogue of X-ray detected clusters of galaxies catalogue and find that the 10 most massive clusters in the sample are consistent with ΛCDM and the Tinker mass function. For the order statistics in redshift, we find a discrepancy between the data and the theoretical distributions, which could in principle indicate a

  3. Educational Linguistics in Practice: Applying the Local Globally and the Global Locally

    ERIC Educational Resources Information Center

    King, Kendall A.; Hult, Francis M.

    2011-01-01

    This volume provides a state-of-the-art snapshot of language and education research and demonstrates ways in which local and global processes are intertwined with language learning, use, and policies. Reflecting but also expanding on Nancy Hornberger's ground-breaking contributions to educational linguistics, this book brings together leading…

  4. Educational Linguistics in Practice: Applying the Local Globally and the Global Locally

    ERIC Educational Resources Information Center

    King, Kendall A.; Hult, Francis M.

    2011-01-01

    This volume provides a state-of-the-art snapshot of language and education research and demonstrates ways in which local and global processes are intertwined with language learning, use, and policies. Reflecting but also expanding on Nancy Hornberger's ground-breaking contributions to educational linguistics, this book brings together leading…

  5. Applying chimera virtual data concepts to cluster finding in the Sloan Sky Survey

    SciTech Connect

    James Annis et al.

    2002-08-13

    The GriPhyN project is one of several major efforts working to enable large-scale data-intensive computation as a routine scientific tool. GriPhyN focuses in particular on virtual data technologies that allow computational procedures and results to be exploited as community resources so that, for example, scientists can not only run their own computations on raw data, but also discover computational procedures developed by others and data produced by these procedures. A request to retrieve data on a particular cluster might thus either lead to the retrieval of the requested data from a local or remote database or the scheduling of a computation to produce the data.

  6. Effect of a localized charge on the stability of Van der Waals clusters

    NASA Astrophysics Data System (ADS)

    Rahinov, Igor; Toker, Yoni; Hansen, Klavs; Schwalm, Dirk; Heber, Oded; Zajfman, Daniel

    2016-12-01

    The stability of anionic (SF6)-N clusters (in the range of N< 23), generated in a supersonic expansion ion source with electron impact ionization, was investigated by measuring their blackbody induced radiative dissociation (BIRD) rates in an electrostatic ion beam trap (EIBT) at room temperature. The lifetime traces of EIBT-stored clusters were subjected to "master equation analysis" and the activation energies, Ea, for the evaporation of a SF6 monomer were extracted. We find that the decay rates of (SF6)-N anionic clusters are larger than those of cationic SF+5(SF6)N-1 measured previously by the same method, and their corresponding activation energies to be smaller. These observations provide further insight into the effect of localized charge on cluster stability.

  7. OmegaWINGS: spectroscopy in the outskirts of local clusters of galaxies

    NASA Astrophysics Data System (ADS)

    Moretti, A.; Gullieuszik, M.; Poggianti, B.; Paccagnella, A.; Couch, W. J.; Vulcani, B.; Bettoni, D.; Fritz, J.; Cava, A.; Fasano, G.; D'Onofrio, M.; Omizzolo, A.

    2017-03-01

    Context. Studies of the properties of low-redshift cluster galaxies suffer, in general, from small spatial coverage of the cluster area. WINGS, the most homogeneous and complete study of galaxies in dense environments to date, obtained spectroscopic redshifts for 48 clusters at a median redshift of 0.05, out to an average distance of approximately 0.5 cluster virial radii. The WINGS photometric survey was recently extended by the VST survey OmegaWINGS to cover the outskirts of a subset of the original cluster sample. Aims: In this work, we present the spectroscopic follow-up of 33 of the 46 clusters of galaxies observed with VST over 1 square degree. The aim of this spectroscopic survey is to enlarge the number of cluster members and study the galaxy characteristics and the cluster dynamical properties out to large radii, reaching the virial radius and beyond. Methods: We used the AAOmega spectrograph at AAT to obtain fiber-integrated spectra covering the wavelength region between 3800 and 9000 Å with a spectral resolution of 3.5-6 Å full width at half maximum (FWHM). Observations were performed using two different configurations and exposure times per cluster. We measured redshifts using both absorption and emission lines and used them to derive the cluster redshifts and velocity dispersions. Results: We present here the redshift measurements for 17 985 galaxies, 7497 of which turned out to be cluster members. The sample magnitude completeness is 80% at V = 20. Thanks to the observing strategy, the radial completeness turned out to be relatively constant (90%) within the AAOmega field of view. The success rate in measuring redshifts is 95%, at all radii. Conclusions: We provide redshifts for the full sample of galaxies in OmegaWINGS clusters together with updated and robust cluster redshift and velocity dispersions. These data, publicly accessible through the CDS and VO archives, will enable evolutionary and environmental studies of cluster properties, providing

  8. Superpixel Segmentation for Polsar Images with Local Iterative Clustering and Heterogeneous Statistical Model

    NASA Astrophysics Data System (ADS)

    Xiang, D.; Ni, W.; Zhang, H.; Wu, J.; Yan, W.; Su, Y.

    2017-09-01

    Superpixel segmentation has an advantage that can well preserve the target shape and details. In this research, an adaptive polarimetric SLIC (Pol-ASLIC) superpixel segmentation method is proposed. First, the spherically invariant random vector (SIRV) product model is adopted to estimate the normalized covariance matrix and texture for each pixel. A new edge detector is then utilized to extract PolSAR image edges for the initialization of central seeds. In the local iterative clustering, multiple cues including polarimetric, texture, and spatial information are considered to define the similarity measure. Moreover, a polarimetric homogeneity measurement is used to automatically determine the tradeoff factor, which can vary from homogeneous areas to heterogeneous areas. Finally, the SLIC superpixel segmentation scheme is applied to the airborne Experimental SAR and PiSAR L-band PolSAR data to demonstrate the effectiveness of this proposed segmentation approach. This proposed algorithm produces compact superpixels which can well adhere to image boundaries in both natural and urban areas. The detail information in heterogeneous areas can be well preserved.

  9. Independent Measurements of the Dynamical Masses of Six Galaxy Clusters in the Local Universe

    NASA Astrophysics Data System (ADS)

    Lee, Jounghun

    2017-04-01

    We present independent measurements of the masses of galaxy clusters in the local universe by employing the Dynamical Mass Estimator (DME) originally developed by Falco et al. In the catalog of the galaxy groups/clusters constructed by Tempel et al. from Sloan Digital Sky Survey Data Release 10, we search for galaxy clusters as the targets around which neighbor galaxies constitute thin straight filamentary structures in the configuration space spanned by the redshifts and the projected distances. Out of the 29 Sloan clusters that have 100 or more member galaxies, a total of six targets are found to have filamentary structures in their bound zones. For each of the six targets, we construct the profile of the recession velocities of the filament galaxies, which depend on the cluster mass and the angle of the filament relative to the line-of-sight direction. Fitting the constructed profile to the universal formula with constant amplitude and slope, we statistically determine the dynamical mass of each cluster and compare it with previous estimates made using the conventional method. The weak and strong points of the DME, as well as its prospects for measuring the dynamical masses of high-z clusters, are discussed.

  10. Multi-cellular natural killer (NK) cell clusters enhance NK cell activation through localizing IL-2 within the cluster

    NASA Astrophysics Data System (ADS)

    Kim, Miju; Kim, Tae-Jin; Kim, Hye Mi; Doh, Junsang; Lee, Kyung-Mi

    2017-01-01

    Multi-cellular cluster formation of natural killer (NK) cells occurs during in vivo priming and potentiates their activation to IL-2. However, the precise mechanism underlying this synergy within NK cell clusters remains unclear. We employed lymphocyte-laden microwell technologies to modulate contact-mediated multi-cellular interactions among activating NK cells and to quantitatively assess the molecular events occurring in multi-cellular clusters of NK cells. NK cells in social microwells, which allow cell-to-cell contact, exhibited significantly higher levels of IL-2 receptor (IL-2R) signaling compared with those in lonesome microwells, which prevent intercellular contact. Further, CD25, an IL-2R α chain, and lytic granules of NK cells in social microwells were polarized toward MTOC. Live cell imaging of lytic granules revealed their dynamic and prolonged polarization toward neighboring NK cells without degranulation. These results suggest that IL-2 bound on CD25 of one NK cells triggered IL-2 signaling of neighboring NK cells. These results were further corroborated by findings that CD25-KO NK cells exhibited lower proliferation than WT NK cells, and when mixed with WT NK cells, underwent significantly higher level of proliferation. These data highlights the existence of IL-2 trans-presentation between NK cells in the local microenvironment where the availability of IL-2 is limited.

  11. Multi-cellular natural killer (NK) cell clusters enhance NK cell activation through localizing IL-2 within the cluster

    PubMed Central

    Kim, Miju; Kim, Tae-Jin; Kim, Hye Mi; Doh, Junsang; Lee, Kyung-Mi

    2017-01-01

    Multi-cellular cluster formation of natural killer (NK) cells occurs during in vivo priming and potentiates their activation to IL-2. However, the precise mechanism underlying this synergy within NK cell clusters remains unclear. We employed lymphocyte-laden microwell technologies to modulate contact-mediated multi-cellular interactions among activating NK cells and to quantitatively assess the molecular events occurring in multi-cellular clusters of NK cells. NK cells in social microwells, which allow cell-to-cell contact, exhibited significantly higher levels of IL-2 receptor (IL-2R) signaling compared with those in lonesome microwells, which prevent intercellular contact. Further, CD25, an IL-2R α chain, and lytic granules of NK cells in social microwells were polarized toward MTOC. Live cell imaging of lytic granules revealed their dynamic and prolonged polarization toward neighboring NK cells without degranulation. These results suggest that IL-2 bound on CD25 of one NK cells triggered IL-2 signaling of neighboring NK cells. These results were further corroborated by findings that CD25-KO NK cells exhibited lower proliferation than WT NK cells, and when mixed with WT NK cells, underwent significantly higher level of proliferation. These data highlights the existence of IL-2 trans-presentation between NK cells in the local microenvironment where the availability of IL-2 is limited. PMID:28074895

  12. MRI tissue classification and bias field estimation based on coherent local intensity clustering: a unified energy minimization framework.

    PubMed

    Li, Chunming; Xu, Chenyang; Anderson, Adam W; Gore, John C

    2009-01-01

    This paper presents a new energy minimization method for simultaneous tissue classification and bias field estimation of magnetic resonance (MR) images. We first derive an important characteristic of local image intensities--the intensities of different tissues within a neighborhood form separable clusters, and the center of each cluster can be well approximated by the product of the bias within the neighborhood and a tissue-dependent constant. We then introduce a coherent local intensity clustering (CLIC) criterion function as a metric to evaluate tissue classification and bias field estimation. An integration of this metric defines an energy on a bias field, membership functions of the tissues, and the parameters that approximate the true signal from the corresponding tissues. Thus, tissue classification and bias field estimation are simultaneously achieved by minimizing this energy. The smoothness of the derived optimal bias field is ensured by the spatially coherent nature of the CLIC criterion function. As a result, no extra effort is needed to smooth the bias field in our method. Moreover, the proposed algorithm is robust to the choice of initial conditions, thereby allowing fully automatic applications. Our algorithm has been applied to high field and ultra high field MR images with promising results.

  13. Self-interaction free local exchange potentials applied to metallic systems

    NASA Astrophysics Data System (ADS)

    Clark, S. J.; Hollins, T. W.; Refson, K.; Gidopoulos, N. I.

    2017-09-01

    We extend the formalism of local exchange methods to calculate and investigate the electronic structure of metals. It is well-known that the Hartree-Fock method when applied to metals shows unphysical behaviour, however the accurate treatment of exchange via DFT’s exact exchange method and using our local Fock exchange method can be used to describe metallic band structures accurately.

  14. Active learning for semi-supervised clustering based on locally linear propagation reconstruction.

    PubMed

    Chang, Chin-Chun; Lin, Po-Yi

    2015-03-01

    The success of semi-supervised clustering relies on the effectiveness of side information. To get effective side information, a new active learner learning pairwise constraints known as must-link and cannot-link constraints is proposed in this paper. Three novel techniques are developed for learning effective pairwise constraints. The first technique is used to identify samples less important to cluster structures. This technique makes use of a kernel version of locally linear embedding for manifold learning. Samples neither important to locally linear propagation reconstructions of other samples nor on flat patches in the learned manifold are regarded as unimportant samples. The second is a novel criterion for query selection. This criterion considers not only the importance of a sample to expanding the space coverage of the learned samples but also the expected number of queries needed to learn the sample. To facilitate semi-supervised clustering, the third technique yields inferred must-links for passing information about flat patches in the learned manifold to semi-supervised clustering algorithms. Experimental results have shown that the learned pairwise constraints can capture the underlying cluster structures and proven the feasibility of the proposed approach. Copyright © 2014 Elsevier Ltd. All rights reserved.

  15. DISCOVERY OF THE MOST ISOLATED GLOBULAR CLUSTER IN THE LOCAL UNIVERSE

    SciTech Connect

    Jang, In Sung; Lim, Sungsoon; Park, Hong Soo; Lee, Myung Gyoon E-mail: slim@astro.snu.ac.kr E-mail: mglee@astro.snu.ac.kr

    2012-05-20

    We report the discovery of two new globular clusters in the remote halos of M81 and M82 in the M81 Group based on Hubble Space Telescope archive images. They are brighter than typical globular clusters (M{sub V} = -9.34 mag for GC-1 and M{sub V} = -10.51 mag for GC-2), and much larger than known globular clusters with similar luminosity in the Milky Way Galaxy and M81. Radial surface brightness profiles for GC-1 and GC-2 do not show any features of tidal truncation in the outer part. They are located much farther from both M81 and M82 in the sky, compared with previously known star clusters in these galaxies. Color-magnitude diagrams of resolved stars in each cluster show a well-defined red giant branch (RGB), indicating that they are metal-poor and old. We derive a low metallicity with [Fe/H] Almost-Equal-To -2.3 and an old age {approx}14 Gyr for GC-2 from the analysis of the absorption lines in its spectrum in the Sloan Digital Sky Survey in comparison with the simple stellar population models. The I-band magnitude of the tip of the RGB for GC-2 is 0.26 mag fainter than that for the halo stars in the same field, showing that GC-2 is {approx}400 kpc behind the M81 halo along our line of sight. The deprojected distance to GC-2 from M81 is much larger than any other known globular clusters in the local universe. This shows that GC-2 is the most isolated globular cluster in the local universe.

  16. Methods for simultaneously identifying coherent local clusters with smooth global patterns in gene expression profiles.

    PubMed

    Tien, Yin-Jing; Lee, Yun-Shien; Wu, Han-Ming; Chen, Chun-Houh

    2008-03-20

    The hierarchical clustering tree (HCT) with a dendrogram 1 and the singular value decomposition (SVD) with a dimension-reduced representative map 2 are popular methods for two-way sorting the gene-by-array matrix map employed in gene expression profiling. While HCT dendrograms tend to optimize local coherent clustering patterns, SVD leading eigenvectors usually identify better global grouping and transitional structures. This study proposes a flipping mechanism for a conventional agglomerative HCT using a rank-two ellipse (R2E, an improved SVD algorithm for sorting purpose) seriation by Chen 3 as an external reference. While HCTs always produce permutations with good local behaviour, the rank-two ellipse seriation gives the best global grouping patterns and smooth transitional trends. The resulting algorithm automatically integrates the desirable properties of each method so that users have access to a clustering and visualization environment for gene expression profiles that preserves coherent local clusters and identifies global grouping trends. We demonstrate, through four examples, that the proposed method not only possesses better numerical and statistical properties, it also provides more meaningful biomedical insights than other sorting algorithms. We suggest that sorted proximity matrices for genes and arrays, in addition to the gene-by-array expression matrix, can greatly aid in the search for comprehensive understanding of gene expression structures. Software for the proposed methods can be obtained at http://gap.stat.sinica.edu.tw/Software/GAP.

  17. Computing the size and number of neuronal clusters in local circuits.

    PubMed

    Perin, Rodrigo; Telefont, Martin; Markram, Henry

    2013-01-01

    The organization of connectivity in neuronal networks is fundamental to understanding the activity and function of neural networks and information processing in the brain. Recent studies show that the neocortex is not only organized in columns and layers but also, within these, into synaptically connected clusters of neurons (Ko et al., 2011; Perin et al., 2011). The recently discovered common neighbor rule, according to which the probability of any two neurons being synaptically connected grows with the number of their common neighbors, is an organizing principle for this local clustering. Here we investigated the theoretical constraints for how the spatial extent of neuronal axonal and dendritic arborization, heretofore described by morphological reach, the density of neurons and the size of the network determine cluster size and numbers within neural networks constructed according to the common neighbor rule. In the formulation we developed, morphological reach, cell density, and network size are sufficient to estimate how many neurons, on average, occur in a cluster and how many clusters exist in a given network. We find that cluster sizes do not grow indefinitely as network parameters increase, but tend to characteristic limiting values.

  18. Local Group and Star Cluster Dynamics from HSTPROMO: The Hubble Space Telescope Proper Motion Collaboration

    NASA Astrophysics Data System (ADS)

    van der Marel, R. P.; Anderson, J.; Bellini, A.; Besla, G.; Bianchini, P.; Boylan-Kolchin, M.; Chaname, J.; Deason, A.; Do, T.; Guhathakurta, P.; Kallivayalil, N.; Lennon, D.; Massari, D.; Meyer, E.; Platais, I.; Sabbi, E.; Sohn, S. T.; Soto, M.; Trenti, M.; Watkins, L.

    2014-03-01

    The Hubble Space Telescope (HST) has proven to be uniquely suited for the measurement of proper motions (PMs) of stars and galaxies in the nearby Universe. Here we summarize the main results and ongoing studies of the HSTPROMO collaboration, which over the past decade has executed some two dozen observational and theoretical HST projects on this topic. This is continuing to revolutionize our dynamical understanding of many objects, including: globular clusters; young star clusters; stars and stellar streams in the Milky Way halo; Local Group galaxies, including dwarf satellite galaxies, the Magellanic Clouds, and the Andromeda galaxy; and AGN black hole Jets.

  19. Quantum correlated cluster mean-field theory applied to the transverse Ising model.

    PubMed

    Zimmer, F M; Schmidt, M; Maziero, Jonas

    2016-06-01

    Mean-field theory (MFT) is one of the main available tools for analytical calculations entailed in investigations regarding many-body systems. Recently, there has been a surge of interest in ameliorating this kind of method, mainly with the aim of incorporating geometric and correlation properties of these systems. The correlated cluster MFT (CCMFT) is an improvement that succeeded quite well in doing that for classical spin systems. Nevertheless, even the CCMFT presents some deficiencies when applied to quantum systems. In this article, we address this issue by proposing the quantum CCMFT (QCCMFT), which, in contrast to its former approach, uses general quantum states in its self-consistent mean-field equations. We apply the introduced QCCMFT to the transverse Ising model in honeycomb, square, and simple cubic lattices and obtain fairly good results both for the Curie temperature of thermal phase transition and for the critical field of quantum phase transition. Actually, our results match those obtained via exact solutions, series expansions or Monte Carlo simulations.

  20. Quantum correlated cluster mean-field theory applied to the transverse Ising model

    NASA Astrophysics Data System (ADS)

    Zimmer, F. M.; Schmidt, M.; Maziero, Jonas

    2016-06-01

    Mean-field theory (MFT) is one of the main available tools for analytical calculations entailed in investigations regarding many-body systems. Recently, there has been a surge of interest in ameliorating this kind of method, mainly with the aim of incorporating geometric and correlation properties of these systems. The correlated cluster MFT (CCMFT) is an improvement that succeeded quite well in doing that for classical spin systems. Nevertheless, even the CCMFT presents some deficiencies when applied to quantum systems. In this article, we address this issue by proposing the quantum CCMFT (QCCMFT), which, in contrast to its former approach, uses general quantum states in its self-consistent mean-field equations. We apply the introduced QCCMFT to the transverse Ising model in honeycomb, square, and simple cubic lattices and obtain fairly good results both for the Curie temperature of thermal phase transition and for the critical field of quantum phase transition. Actually, our results match those obtained via exact solutions, series expansions or Monte Carlo simulations.

  1. Spatial clustering and local risk of leprosy in São Paulo, Brazil.

    PubMed

    Ramos, Antônio Carlos Vieira; Yamamura, Mellina; Arroyo, Luiz Henrique; Popolin, Marcela Paschoal; Chiaravalloti Neto, Francisco; Palha, Pedro Fredemir; Uchoa, Severina Alice da Costa; Pieri, Flávia Meneguetti; Pinto, Ione Carvalho; Fiorati, Regina Célia; Queiroz, Ana Angélica Rêgo de; Belchior, Aylana de Souza; Dos Santos, Danielle Talita; Garcia, Maria Concebida da Cunha; Crispim, Juliane de Almeida; Alves, Luana Seles; Berra, Thaís Zamboni; Arcêncio, Ricardo Alexandre

    2017-02-01

    Although the detection rate is decreasing, the proportion of new cases with WHO grade 2 disability (G2D) is increasing, creating concern among policy makers and the Brazilian government. This study aimed to identify spatial clustering of leprosy and classify high-risk areas in a major leprosy cluster using the SatScan method. Data were obtained including all leprosy cases diagnosed between January 2006 and December 2013. In addition to the clinical variable, information was also gathered regarding the G2D of the patient at diagnosis and after treatment. The Scan Spatial statistic test, developed by Kulldorff e Nagarwalla, was used to identify spatial clustering and to measure the local risk (Relative Risk-RR) of leprosy. Maps considering these risks and their confidence intervals were constructed. A total of 434 cases were identified, including 188 (43.31%) borderline leprosy and 101 (23.28%) lepromatous leprosy cases. There was a predominance of males, with ages ranging from 15 to 59 years, and 51 patients (11.75%) presented G2D. Two significant spatial clusters and three significant spatial-temporal clusters were also observed. The main spatial cluster (p = 0.000) contained 90 census tracts, a population of approximately 58,438 inhabitants, detection rate of 22.6 cases per 100,000 people and RR of approximately 3.41 (95%CI = 2.721-4.267). Regarding the spatial-temporal clusters, two clusters were observed, with RR ranging between 24.35 (95%CI = 11.133-52.984) and 15.24 (95%CI = 10.114-22.919). These findings could contribute to improvements in policies and programming, aiming for the eradication of leprosy in Brazil. The Spatial Scan statistic test was found to be an interesting resource for health managers and healthcare professionals to map the vulnerability of areas in terms of leprosy transmission risk and areas of underreporting.

  2. Acoustic Cluster Therapy (ACT) - pre-clinical proof of principle for local drug delivery and enhanced uptake.

    PubMed

    Wamel, Annemieke van; Healey, Andrew; Sontum, Per Christian; Kvåle, Svein; Bush, Nigel; Bamber, Jeff; de Lange Davies, Catharina

    2016-02-28

    Proof of principle for local drug delivery with Acoustic Cluster Therapy (ACT) was demonstrated in a human prostate adenocarcinoma growing in athymic mice, using near infrared (NIR) dyes as model molecules. A dispersion of negatively charged microbubble/positively charged microdroplet clusters are injected i.v., activated within the target pathology by diagnostic ultrasound (US), undergo an ensuing liquid-to-gas phase shift and transiently deposit 20-30μm large bubbles in the microvasculature, occluding blood flow for ~5-10min. Further application of low frequency US induces biomechanical effects that increase the vascular permeability, leading to a locally enhanced extravasation of components from the vascular compartment (e.g., released or co-administered drugs). Results demonstrated deposition of activated bubbles in tumor vasculature. Following ACT treatment, a significant and tumor specific increase in the uptake of a co-administered macromolecular NIR dye was shown. In addition, ACT compound loaded with a lipophilic NIR dye to the microdroplet component was shown to facilitate local release and tumor specific uptake. Whereas the mechanisms behind the observed increased and tumor specific uptake are not fully elucidated, it is demonstrated that the ACT concept can be applied as a versatile technique for targeted drug delivery.

  3. Investigating Faculty Familiarity with Assessment Terminology by Applying Cluster Analysis to Interpret Survey Data

    ERIC Educational Resources Information Center

    Raker, Jeffrey R.; Holme, Thomas A.

    2014-01-01

    A cluster analysis was conducted with a set of survey data on chemistry faculty familiarity with 13 assessment terms. Cluster groupings suggest a high, middle, and low overall familiarity with the terminology and an independent high and low familiarity with terms related to fundamental statistics. The six resultant clusters were found to be…

  4. Investigating Faculty Familiarity with Assessment Terminology by Applying Cluster Analysis to Interpret Survey Data

    ERIC Educational Resources Information Center

    Raker, Jeffrey R.; Holme, Thomas A.

    2014-01-01

    A cluster analysis was conducted with a set of survey data on chemistry faculty familiarity with 13 assessment terms. Cluster groupings suggest a high, middle, and low overall familiarity with the terminology and an independent high and low familiarity with terms related to fundamental statistics. The six resultant clusters were found to be…

  5. Analyzing Patients' Values by Applying Cluster Analysis and LRFM Model in a Pediatric Dental Clinic in Taiwan

    PubMed Central

    Lin, Shih-Yen; Liu, Chih-Wei

    2014-01-01

    This study combines cluster analysis and LRFM (length, recency, frequency, and monetary) model in a pediatric dental clinic in Taiwan to analyze patients' values. A two-stage approach by self-organizing maps and K-means method is applied to segment 1,462 patients into twelve clusters. The average values of L, R, and F excluding monetary covered by national health insurance program are computed for each cluster. In addition, customer value matrix is used to analyze customer values of twelve clusters in terms of frequency and monetary. Customer relationship matrix considering length and recency is also applied to classify different types of customers from these twelve clusters. The results show that three clusters can be classified into loyal patients with L, R, and F values greater than the respective average L, R, and F values, while three clusters can be viewed as lost patients without any variable above the average values of L, R, and F. When different types of patients are identified, marketing strategies can be designed to meet different patients' needs. PMID:25045741

  6. Analyzing patients' values by applying cluster analysis and LRFM model in a pediatric dental clinic in Taiwan.

    PubMed

    Wu, Hsin-Hung; Lin, Shih-Yen; Liu, Chih-Wei

    2014-01-01

    This study combines cluster analysis and LRFM (length, recency, frequency, and monetary) model in a pediatric dental clinic in Taiwan to analyze patients' values. A two-stage approach by self-organizing maps and K-means method is applied to segment 1,462 patients into twelve clusters. The average values of L, R, and F excluding monetary covered by national health insurance program are computed for each cluster. In addition, customer value matrix is used to analyze customer values of twelve clusters in terms of frequency and monetary. Customer relationship matrix considering length and recency is also applied to classify different types of customers from these twelve clusters. The results show that three clusters can be classified into loyal patients with L, R, and F values greater than the respective average L, R, and F values, while three clusters can be viewed as lost patients without any variable above the average values of L, R, and F. When different types of patients are identified, marketing strategies can be designed to meet different patients' needs.

  7. Improved cluster-in-molecule local correlation approach for electron correlation calculation of large systems.

    PubMed

    Guo, Yang; Li, Wei; Li, Shuhua

    2014-10-02

    An improved cluster-in-molecule (CIM) local correlation approach is developed to allow electron correlation calculations of large systems more accurate and faster. We have proposed a refined strategy of constructing virtual LMOs of various clusters, which is suitable for basis sets of various types. To recover medium-range electron correlation, which is important for quantitative descriptions of large systems, we find that a larger distance threshold (ξ) is necessary for highly accurate results. Our illustrative calculations show that the present CIM-MP2 (second-order Møller-Plesser perturbation theory, MP2) or CIM-CCSD (coupled cluster singles and doubles, CCSD) scheme with a suitable ξ value is capable of recovering more than 99.8% correlation energies for a wide range of systems at different basis sets. Furthermore, the present CIM-MP2 scheme can provide reliable relative energy differences as the conventional MP2 method for secondary structures of polypeptides.

  8. Geographic information systems and pharmacoepidemiology: using spatial cluster detection to monitor local patterns of prescription opioid abuse.

    PubMed

    Brownstein, John S; Green, Traci C; Cassidy, Theresa A; Butler, Stephen F

    2010-06-01

    Understanding the spatial distribution of opioid abuse at the local level may facilitate public health interventions. Using patient-level data from addiction treatment facilities in New Mexico from ASI-MV Connect, we applied geographic information system (GIS) in combination with a spatial scan statistic to generate risk maps of prescription opioid abuse and identify clusters of product- and compound-specific abuse. Prescribed opioid volume data was used to determine whether identified clusters are beyond geographic differences in availability. Data on 24 452 patients residing in New Mexico were collected. Among those patients, 1779 (7.3%) reported abusing any prescription opioid (past 30 days). According to opioid type, 979 patients (4.0%) reported abuse of any hydrocodone, 1007 (4.1%) for any oxycodone, 108 (0.4%) for morphine, 507 (2.1%) for Vicodin or generic equivalent, 390 (1.6%) for OxyContin, and 63 (0.2%) for MS Contin or generic equivalent. Highest rates of abuse were found in the area surrounding Albuquerque with 8.6 patients indicating abuse per 100 interviewed patients. We found clustering of abuse around Albuquerque (P = 0.001; Relative Risk = 1.35, and a radius of 146 km). At the compound level, we found that drug availability was partly responsible for clustering of prescription opioid abuse. After accounting for drug availability, we identified a second foci of Vicodin abuse in the southern rural portion of the state near Las Cruces, NM and El Paso, Texas and bordering Mexico (RR = 2.1; P = 0.001). A better understanding of local risk distribution may have implications for response strategies to future introductions of prescription opioids.

  9. Dark matter searches with Cherenkov telescopes: nearby dwarf galaxies or local galaxy clusters?

    SciTech Connect

    Sánchez-Conde, Miguel A.; Cannoni, Mirco; Gómez, Mario E.; Zandanel, Fabio; Prada, Francisco E-mail: mirco.cannoni@dfa.uhu.es E-mail: mario.gomez@dfa.uhu.es

    2011-12-01

    In this paper, we compare dwarf galaxies and galaxy clusters in order to elucidate which object class is the best target for gamma-ray DM searches with imaging atmospheric Cherenkov telescopes (IACTs). We have built a mixed dwarfs+clusters sample containing some of the most promising nearby dwarf galaxies (Draco, Ursa Minor, Wilman 1 and Segue 1) and local galaxy clusters (Perseus, Coma, Ophiuchus, Virgo, Fornax, NGC 5813 and NGC 5846), and then compute their DM annihilation flux profiles by making use of the latest modeling of their DM density profiles. We also include in our calculations the effect of DM substructure. Willman 1 appears as the best candidate in the sample. However, its mass modeling is still rather uncertain, so probably other candidates with less uncertainties and quite similar fluxes, namely Ursa Minor and Segue 1, might be better options. As for galaxy clusters, Virgo represents the one with the highest flux. However, its large spatial extension can be a serious handicap for IACT observations and posterior data analysis. Yet, other local galaxy cluster candidates with more moderate emission regions, such as Perseus, may represent good alternatives. After comparing dwarfs and clusters, we found that the former exhibit annihilation flux profiles that, at the center, are roughly one order of magnitude higher than those of clusters, although galaxy clusters can yield similar, or even higher, integrated fluxes for the whole object once substructure is taken into account. Even when any of these objects are strictly point-like according to the properties of their annihilation signals, we conclude that dwarf galaxies are best suited for observational strategies based on the search of point-like sources, while galaxy clusters represent best targets for analyses that can deal with rather extended emissions. Finally, we study the detection prospects for present and future IACTs in the framework of the constrained minimal supersymmetric standard model. We

  10. Dark Matter Searches with Cherenkov Telescopes: Nearby Dwarf Galaxies or Local Galaxy Clusters?

    SciTech Connect

    Sanchez-Conde, Miguel A.; Cannoni, Mirco; Zandanel, Fabio; Gomez, Mario E.; Prada, Francisco; /IAA, Granada

    2012-06-06

    In this paper, we compare dwarf galaxies and galaxy clusters in order to elucidate which object class is the best target for gamma-ray DM searches with imaging atmospheric Cherenkov telescopes (IACTs). We have built a mixed dwarfs+clusters sample containing some of the most promising nearby dwarf galaxies (Draco, Ursa Minor, Wilman 1 and Segue 1) and local galaxy clusters (Perseus, Coma, Ophiuchus, Virgo, Fornax, NGC 5813 and NGC 5846), and then compute their DM annihilation flux profiles by making use of the latest modeling of their DM density profiles. We also include in our calculations the effect of DM substructure. Willman 1 appears as the best candidate in the sample. However, its mass modeling is still rather uncertain, so probably other candidates with less uncertainties and quite similar fluxes, namely Ursa Minor and Segue 1, might be better options. As for galaxy clusters, Virgo represents the one with the highest flux. However, its large spatial extension can be a serious handicap for IACT observations and posterior data analysis. Yet, other local galaxy cluster candidates with more moderate emission regions, such as Perseus, may represent good alternatives. After comparing dwarfs and clusters, we found that the former exhibit annihilation flux profiles that, at the center, are roughly one order of magnitude higher than those of clusters, although galaxy clusters can yield similar, or even higher, integrated fluxes for the whole object once substructure is taken into account. Even when any of these objects are strictly point-like according to the properties of their annihilation signals, we conclude that dwarf galaxies are best suited for observational strategies based on the search of point-like sources, while galaxy clusters represent best targets for analyses that can deal with rather extended emissions. Finally, we study the detection prospects for present and future IACTs in the framework of the constrained minimal supersymmetric standard model. We

  11. ALMA Reveals Potential Localized Dust Enrichment from Massive Star Clusters in II Zw 40

    NASA Astrophysics Data System (ADS)

    Consiglio, S. Michelle; Turner, Jean L.; Beck, Sara; Meier, David S.

    2016-12-01

    We present subarcsecond images of submillimeter CO and continuum emission from a local galaxy forming massive star clusters: the blue compact dwarf galaxy II Zw 40. At ˜0.″4 resolution (20 pc), the CO(3-2), CO(1-0), 3 mm, and 870 μm continuum maps illustrate star formation on the scales of individual molecular clouds. Dust contributes about one-third of the 870 μm continuum emission, with free-free accounting for the rest. On these scales, there is not a good correspondence between gas, dust, and free-free emission. Dust continuum is enhanced toward the star-forming region as compared to the CO emission. We suggest that an unexpectedly low and spatially variable gas-to-dust ratio is the result of rapid and localized dust enrichment of clouds by the massive clusters of the starburst.

  12. Clustered localization of STAT3 during the cell cycle detected by super-resolution fluorescence microscopy

    NASA Astrophysics Data System (ADS)

    Gao, Jing; Chen, Junling; Cai, Mingjun; Xu, Haijiao; Jiang, Junguang; Tong, Ti; Wang, Hongda

    2017-06-01

    Signal transducer and activator of transcription 3 (STAT3) plays a key role in various cellular processes such as cell proliferation, differentiation, apoptosis and immune responses. In particular, STAT3 has emerged as a potential molecular target for cancer therapy. The functional role and standard activation mechanism of STAT3 have been well studied, however, the spatial distribution of STAT3 during the cell cycle is poorly known. Therefore, it is indispensable to study STAT3 spatial arrangement and nuclear-cytoplasimic localization at the different phase of cell cycle in cancer cells. By direct stochastic optical reconstruction microscopy imaging, we find that STAT3 forms various number and size of clusters at the different cell-cycle stage, which could not be clearly observed by conventional fluorescent microscopy. STAT3 clusters get more and larger gradually from G1 to G2 phase, during which time transcription and other related activities goes on consistently. The results suggest that there is an intimate relationship between the clustered characteristic of STAT3 and the cell-cycle behavior. Meanwhile, clustering would facilitate STAT3 rapid response to activating signals due to short distances between molecules. Our data might open a new door to develop an antitumor drug for inhibiting STAT3 signaling pathway by destroying its clusters.

  13. Local and cluster critical dynamics of the 3d random-site Ising model

    NASA Astrophysics Data System (ADS)

    Ivaneyko, D.; Ilnytskyi, J.; Berche, B.; Holovatch, Yu.

    2006-10-01

    We present the results of Monte Carlo simulations for the critical dynamics of the three-dimensional site-diluted quenched Ising model. Three different dynamics are considered, these correspond to the local update Metropolis scheme as well as to the Swendsen-Wang and Wolff cluster algorithms. The lattice sizes of L=10-96 are analysed by a finite-size-scaling technique. The site dilution concentration p=0.85 was chosen to minimize the correction-to-scaling effects. We calculate numerical values of the dynamical critical exponents for the integrated and exponential autocorrelation times for energy and magnetization. As expected, cluster algorithms are characterized by lower values of dynamical critical exponent than the local one: also in the case of dilution critical slowing down is more pronounced for the Metropolis algorithm. However, the striking feature of our estimates is that they suggest that dilution leads to decrease of the dynamical critical exponent for the cluster algorithms. This phenomenon is quite opposite to the local dynamics, where dilution enhances critical slowing down.

  14. The Effect of Applied Tensile Stress on Localized Corrosion in Sensitized AA5083

    DTIC Science & Technology

    2015-09-01

    100°C. The sensitized samples were subjected to elastic tensile loading using a 4-point bend rig while being exposed to a 0.6 molar saltwater solution ...TENSILE STRESS ON LOCALIZED CORROSION IN SENSITIZED AA5083 by Roy T. Johnston September 2015 Thesis Advisor: Sarath K. Menon Co...AND DATES COVERED Master’s thesis 4. TITLE AND SUBTITLE THE EFFECT OF APPLIED TENSILE STRESS ON LOCALIZED CORROSION IN SENSITIZED AA5083 5

  15. The gaseous proto-cluster as a product of gravo-turbulent interaction: modified local environment for stellar cluster formation?

    NASA Astrophysics Data System (ADS)

    Lee, Y.-N.; Hennebelle, P.

    2016-12-01

    Stars are often observed to form in clusters, while the formation of the gaseous proto-cluster precedes that of the stellar cluster. We discuss the assembly of gas via gravo-turbulent reprocessing inside collapsing molecular clouds, and demonstrate that virial equilibrium is established for the gaseous proto-cluster, of which the higher density is favorable for clustered star formation, and that some physical characteristics of the stellar cluster are inherited from the gaseous proto-cluster. We introduce an analytical two-dimensional virial model to account for the quasi-stationary accreting gaseous proto-cluster which has non-negligible rotation. Results are compared to observations and simulations and the fact that gaseous proto-clusters lie on an equilibrium sequence may imply that star formation could be to some extent disentangled from larger scale physics, offering an encouraging explanation for the universality of IMF.

  16. Does clinical equipoise apply to cluster randomized trials in health research?

    PubMed Central

    2011-01-01

    This article is part of a series of papers examining ethical issues in cluster randomized trials (CRTs) in health research. In the introductory paper in this series, Weijer and colleagues set out six areas of inquiry that must be addressed if the cluster trial is to be set on a firm ethical foundation. This paper addresses the third of the questions posed, namely, does clinical equipoise apply to CRTs in health research? The ethical principle of beneficence is the moral obligation not to harm needlessly and, when possible, to promote the welfare of research subjects. Two related ethical problems have been discussed in the CRT literature. First, are control groups that receive only usual care unduly disadvantaged? Second, when accumulating data suggests the superiority of one intervention in a trial, is there an ethical obligation to act? In individually randomized trials involving patients, similar questions are addressed by the concept of clinical equipoise, that is, the ethical requirement that, at the start of a trial, there be a state of honest, professional disagreement in the community of expert practitioners as to the preferred treatment. Since CRTs may not involve physician-researchers and patient-subjects, the applicability of clinical equipoise to CRTs is uncertain. Here we argue that clinical equipoise may be usefully grounded in a trust relationship between the state and research subjects, and, as a result, clinical equipoise is applicable to CRTs. Clinical equipoise is used to argue that control groups receiving only usual care are not disadvantaged so long as the evidence supporting the experimental and control interventions is such that experts would disagree as to which is preferred. Further, while data accumulating during the course of a CRT may favor one intervention over another, clinical equipoise supports continuing the trial until the results are likely to be broadly convincing, often coinciding with the planned completion of the trial

  17. An Analysis of the Optimal Multiobjective Inventory Clustering Decision with Small Quantity and Great Variety Inventory by Applying a DPSO

    PubMed Central

    Li, Meng-Hua

    2014-01-01

    When an enterprise has thousands of varieties in its inventory, the use of a single management method could not be a feasible approach. A better way to manage this problem would be to categorise inventory items into several clusters according to inventory decisions and to use different management methods for managing different clusters. The present study applies DPSO (dynamic particle swarm optimisation) to a problem of clustering of inventory items. Without the requirement of prior inventory knowledge, inventory items are automatically clustered into near optimal clustering number. The obtained clustering results should satisfy the inventory objective equation, which consists of different objectives such as total cost, backorder rate, demand relevance, and inventory turnover rate. This study integrates the above four objectives into a multiobjective equation, and inputs the actual inventory items of the enterprise into DPSO. In comparison with other clustering methods, the proposed method can consider different objectives and obtain an overall better solution to obtain better convergence results and inventory decisions. PMID:25197713

  18. Shape index distribution based local surface complexity applied to the human cortex

    PubMed Central

    Kim, Sun Hyung; Fonov, Vladimir; Collins, D. Louis; Gerig, Guido; Styner, Martin A.

    2015-01-01

    The quantification of local surface complexity in the human cortex has shown to be of interest in investigating population differences as well as developmental changes in neurodegenerative or neurodevelopment diseases. We propose a novel assessment method that represents local complexity as the difference between the observed distributions of local surface topology to its best-fit basic topology model within a given local neighborhood. This distribution difference is estimated via Earth Move Distance (EMD) over the histogram within the local neighborhood of the surface topology quantified via the Shape Index (SI) measure. The EMD scores have a range from simple complexity (0.0), which indicates a consistent local surface topology, up to high complexity (1.0), which indicates a highly variable local surface topology. The basic topology models are categorized as 9 geometric situation modeling situations such as crowns, ridges and fundi of cortical gyro and sulci. We apply a geodesic kernel to calculate the local SI histrogram distribution within a given region. In our experiments, we obtained the results of local complexity that shows generally higher complexity in the gyral/sulcal wall regions and lower complexity in some gyral ridges and lowest complexity in sulcal fundus areas. In addition, we show expected, preliminary results of increased surface complexity across most of the cortical surface within the first years of postnatal life, hypothesized to be due to the changes such as development of sulcal pits. PMID:26028803

  19. Quantum Cluster Equilibrium Theory Applied in Hydrogen Bond Number Studies of Water. 1. Assessment of the Quantum Cluster Equilibrium Model for Liquid Water.

    PubMed

    Lehmann, S B C; Spickermann, C; Kirchner, B

    2009-06-09

    Different cluster sets containing only 2-fold coordinated water, 2- and 3-fold coordinated water, and 2-fold, 3-fold, and tetrahedrally coordinated water molecules were investigated by applying second-order Møller-Plesset perturbation theory and density functional theory based on generalized gradient approximation functionals in the framework of the quantum cluster equilibrium theory. We found an improvement of the calculated isobars at low temperatures if tetrahedrally coordinated water molecules were included in the set of 2-fold hydrogen-bonded clusters. This was also reflected in a reduced parameter for the intercluster interaction. If all parameters were kept constant and only the electronic structure methods were varied, large basis set dependencies in the liquid state for the density functional theory results were found. The behavior of the intercluster parameter was also examined for the case that cooperative effects were neglected. The values were 3 times as large as in the calculations including the total electronic structure. Furthermore, these effects are more severe in the tetrahedrally coordinated clusters. Different populations were considered, one weighted by the total number of clusters and one depending on the monomers.

  20. Segmenting Business Students Using Cluster Analysis Applied to Student Satisfaction Survey Results

    ERIC Educational Resources Information Center

    Gibson, Allen

    2009-01-01

    This paper demonstrates a new application of cluster analysis to segment business school students according to their degree of satisfaction with various aspects of the academic program. The resulting clusters provide additional insight into drivers of student satisfaction that are not evident from analysis of the responses of the student body as a…

  1. Applying Clustering to Statistical Analysis of Student Reasoning about Two-Dimensional Kinematics

    ERIC Educational Resources Information Center

    Springuel, R. Padraic; Wittman, Michael C.; Thompson, John R.

    2007-01-01

    We use clustering, an analysis method not presently common to the physics education research community, to group and characterize student responses to written questions about two-dimensional kinematics. Previously, clustering has been used to analyze multiple-choice data; we analyze free-response data that includes both sketches of vectors and…

  2. Comparison and evaluation of network clustering algorithms applied to genetic interaction networks.

    PubMed

    Hou, Lin; Wang, Lin; Berg, Arthur; Qian, Minping; Zhu, Yunping; Li, Fangting; Deng, Minghua

    2012-01-01

    The goal of network clustering algorithms detect dense clusters in a network, and provide a first step towards the understanding of large scale biological networks. With numerous recent advances in biotechnologies, large-scale genetic interactions are widely available, but there is a limited understanding of which clustering algorithms may be most effective. In order to address this problem, we conducted a systematic study to compare and evaluate six clustering algorithms in analyzing genetic interaction networks, and investigated influencing factors in choosing algorithms. The algorithms considered in this comparison include hierarchical clustering, topological overlap matrix, bi-clustering, Markov clustering, Bayesian discriminant analysis based community detection, and variational Bayes approach to modularity. Both experimentally identified and synthetically constructed networks were used in this comparison. The accuracy of the algorithms is measured by the Jaccard index in comparing predicted gene modules with benchmark gene sets. The results suggest that the choice differs according to the network topology and evaluation criteria. Hierarchical clustering showed to be best at predicting protein complexes; Bayesian discriminant analysis based community detection proved best under epistatic miniarray profile (EMAP) datasets; the variational Bayes approach to modularity was noticeably better than the other algorithms in the genome-scale networks.

  3. Modeling the formation of ion clusters by applying classical nucleation theory

    NASA Astrophysics Data System (ADS)

    Yue, G. K.

    Experiments have been conducted to study the clustering of atmospheric trace gases around ion cores (Castleman and Tang, 1972; Searcy and Fenn, 1974; Castleman, 1978). The classical liquid-drop model is used to investigate this ion-induced formation mechanism. Results obtained from models of the distribution of Pb(+)-(H2O)n and H(+)-(H2O)n type clusters under various conditions are compared with experimental results. The distribution of water-ion clusters in the atmosphere as a function of altitude is calculated. In situ measurements of the water-ion cluster distributions in the upper atmosphere are then compared with present predictions. It is concluded that the classical nucleation theory can be used to predict rough estimates for ion cluster sizes under many conditions.

  4. Modeling the formation of ion clusters by applying classical nucleation theory. [aerosol mechanisms

    NASA Technical Reports Server (NTRS)

    Yue, G. K.

    1981-01-01

    Experiments have been conducted to study the clustering of atmospheric trace gases around ion cores (Castleman and Tang, 1972; Searcy and Fenn, 1974; Castleman, 1978). The classical liquid-drop model is used to investigate this ion-induced formation mechanism. Results obtained from models of the distribution of Pb(+)-(H2O)n and H(+)-(H2O)n type clusters under various conditions are compared with experimental results. The distribution of water-ion clusters in the atmosphere as a function of altitude is calculated. In situ measurements of the water-ion cluster distributions in the upper atmosphere are then compared with present predictions. It is concluded that the classical nucleation theory can be used to predict rough estimates for ion cluster sizes under many conditions.

  5. Obscenity and Indecency: National vs. Local Standards as Applied to Cable Television.

    ERIC Educational Resources Information Center

    Wollert, James A.; Muth, Thomas A.

    The argument advanced in this paper maintains that cable television differs from broadcasting, due to the local character of certain cable services; that the current obscenity standards, as articulated by the Supreme Court, mandate community definitions of obscenity; and that such Supreme Court decisions apply to cable television. Separate…

  6. Obscenity and Indecency: National vs. Local Standards as Applied to Cable Television.

    ERIC Educational Resources Information Center

    Wollert, James A.; Muth, Thomas A.

    The argument advanced in this paper maintains that cable television differs from broadcasting, due to the local character of certain cable services; that the current obscenity standards, as articulated by the Supreme Court, mandate community definitions of obscenity; and that such Supreme Court decisions apply to cable television. Separate…

  7. On the local optimal solutions of metabolic regulatory networks using information guided genetic algorithm approach and clustering analysis.

    PubMed

    Zheng, Ying; Yeh, Chen-Wei; Yang, Chi-Da; Jang, Shi-Shang; Chu, I-Ming

    2007-08-31

    Biological information generated by high-throughput technology has made systems approach feasible for many biological problems. By this approach, optimization of metabolic pathway has been successfully applied in the amino acid production. However, in this technique, gene modifications of metabolic control architecture as well as enzyme expression levels are coupled and result in a mixed integer nonlinear programming problem. Furthermore, the stoichiometric complexity of metabolic pathway, along with strong nonlinear behaviour of the regulatory kinetic models, directs a highly rugged contour in the whole optimization problem. There may exist local optimal solutions wherein the same level of production through different flux distributions compared with global optimum. The purpose of this work is to develop a novel stochastic optimization approach-information guided genetic algorithm (IGA) to discover the local optima with different levels of modification of the regulatory loop and production rates. The novelties of this work include the information theory, local search, and clustering analysis to discover the local optima which have physical meaning among the qualified solutions.

  8. A new Self-Adaptive disPatching System for local clusters

    NASA Astrophysics Data System (ADS)

    Kan, Bowen; Shi, Jingyan; Lei, Xiaofeng

    2015-12-01

    The scheduler is one of the most important components of a high performance cluster. This paper introduces a self-adaptive dispatching system (SAPS) based on Torque[1] and Maui[2]. It promotes cluster resource utilization and improves the overall speed of tasks. It provides some extra functions for administrators and users. First of all, in order to allow the scheduling of GPUs, a GPU scheduling module based on Torque and Maui has been developed. Second, SAPS analyses the relationship between the number of queueing jobs and the idle job slots, and then tunes the priority of users’ jobs dynamically. This means more jobs run and fewer job slots are idle. Third, integrating with the monitoring function, SAPS excludes nodes in error states as detected by the monitor, and returns them to the cluster after the nodes have recovered. In addition, SAPS provides a series of function modules including a batch monitoring management module, a comprehensive scheduling accounting module and a real-time alarm module. The aim of SAPS is to enhance the reliability and stability of Torque and Maui. Currently, SAPS has been running stably on a local cluster at IHEP (Institute of High Energy Physics, Chinese Academy of Sciences), with more than 12,000 cpu cores and 50,000 jobs running each day. Monitoring has shown that resource utilization has been improved by more than 26%, and the management work for both administrator and users has been reduced greatly.

  9. No sign (yet) of intergalactic globular clusters in the Local Group

    NASA Astrophysics Data System (ADS)

    Mackey, A. D.; Beasley, M. A.; Leaman, R.

    2016-07-01

    We present Gemini Multi-Object Spectrograph (GMOS) imaging of 12 candidate intergalactic globular clusters (IGCs) in the Local Group, identified in a recent survey of the Sloan Digital Sky Survey (SDSS) footprint by di Tullio Zinn & Zinn. Our image quality is sufficiently high, at ˜0.4-0.7 arcsec, that we are able to unambiguously classify all 12 targets as distant galaxies. To reinforce this conclusion we use GMOS images of globular clusters in the M31 halo, taken under very similar conditions, to show that any genuine clusters in the putative IGC sample would be straightforward to distinguish. Based on the stated sensitivity of the di Tullio Zinn & Zinn search algorithm, we conclude that there cannot be a significant number of IGCs with MV ≤ -6 lying unseen in the SDSS area if their properties mirror those of globular clusters in the outskirts of M31 - even a population of 4 would have only a ≈1 per cent chance of non-detection.

  10. Performance of Extended Local Clustering Organization (LCO) for Large Scale Job-Shop Scheduling Problem (JSP)

    NASA Astrophysics Data System (ADS)

    Konno, Yohko; Suzuki, Keiji

    This paper describes an approach to development of a solution algorithm of a general-purpose for large scale problems using “Local Clustering Organization (LCO)” as a new solution for Job-shop scheduling problem (JSP). Using a performance effective large scale scheduling in the study of usual LCO, a solving JSP keep stability induced better solution is examined. In this study for an improvement of a performance of a solution for JSP, processes to a optimization by LCO is examined, and a scheduling solution-structure is extended to a new solution-structure based on machine-division. A solving method introduced into effective local clustering for the solution-structure is proposed as an extended LCO. An extended LCO has an algorithm which improves scheduling evaluation efficiently by clustering of parallel search which extends over plural machines. A result verified by an application of extended LCO on various scale of problems proved to conduce to minimizing make-span and improving on the stable performance.

  11. Spatial clustering and local risk of leprosy in São Paulo, Brazil

    PubMed Central

    Yamamura, Mellina; Arroyo, Luiz Henrique; Popolin, Marcela Paschoal; Chiaravalloti Neto, Francisco; Palha, Pedro Fredemir; Uchoa, Severina Alice da Costa; Pieri, Flávia Meneguetti; Pinto, Ione Carvalho; Fiorati, Regina Célia; de Queiroz, Ana Angélica Rêgo; Belchior, Aylana de Souza; dos Santos, Danielle Talita; Garcia, Maria Concebida da Cunha; Crispim, Juliane de Almeida; Alves, Luana Seles; Berra, Thaís Zamboni; Arcêncio, Ricardo Alexandre

    2017-01-01

    Background Although the detection rate is decreasing, the proportion of new cases with WHO grade 2 disability (G2D) is increasing, creating concern among policy makers and the Brazilian government. This study aimed to identify spatial clustering of leprosy and classify high-risk areas in a major leprosy cluster using the SatScan method. Methods Data were obtained including all leprosy cases diagnosed between January 2006 and December 2013. In addition to the clinical variable, information was also gathered regarding the G2D of the patient at diagnosis and after treatment. The Scan Spatial statistic test, developed by Kulldorff e Nagarwalla, was used to identify spatial clustering and to measure the local risk (Relative Risk—RR) of leprosy. Maps considering these risks and their confidence intervals were constructed. Results A total of 434 cases were identified, including 188 (43.31%) borderline leprosy and 101 (23.28%) lepromatous leprosy cases. There was a predominance of males, with ages ranging from 15 to 59 years, and 51 patients (11.75%) presented G2D. Two significant spatial clusters and three significant spatial-temporal clusters were also observed. The main spatial cluster (p = 0.000) contained 90 census tracts, a population of approximately 58,438 inhabitants, detection rate of 22.6 cases per 100,000 people and RR of approximately 3.41 (95%CI = 2.721–4.267). Regarding the spatial-temporal clusters, two clusters were observed, with RR ranging between 24.35 (95%CI = 11.133–52.984) and 15.24 (95%CI = 10.114–22.919). Conclusion These findings could contribute to improvements in policies and programming, aiming for the eradication of leprosy in Brazil. The Spatial Scan statistic test was found to be an interesting resource for health managers and healthcare professionals to map the vulnerability of areas in terms of leprosy transmission risk and areas of underreporting. PMID:28241038

  12. Photoionization cross section by Stieltjes imaging applied to coupled cluster Lanczos pseudo-spectra.

    PubMed

    Cukras, Janusz; Coriani, Sonia; Decleva, Piero; Christiansen, Ove; Norman, Patrick

    2013-09-07

    A recently implemented asymmetric Lanczos algorithm for computing (complex) linear response functions within the coupled cluster singles (CCS), coupled cluster singles and iterative approximate doubles (CC2), and coupled cluster singles and doubles (CCSD) is coupled to a Stieltjes imaging technique in order to describe the photoionization cross section of atoms and molecules, in the spirit of a similar procedure recently proposed by Averbukh and co-workers within the Algebraic Diagrammatic Construction approach. Pilot results are reported for the atoms He, Ne, and Ar and for the molecules H2, H2O, NH3, HF, CO, and CO2.

  13. Photoionization cross section by Stieltjes imaging applied to coupled cluster Lanczos pseudo-spectra

    SciTech Connect

    Cukras, Janusz; Coriani, Sonia; Decleva, Piero; Christiansen, Ove; Norman, Patrick

    2013-09-07

    A recently implemented asymmetric Lanczos algorithm for computing (complex) linear response functions within the coupled cluster singles (CCS), coupled cluster singles and iterative approximate doubles (CC2), and coupled cluster singles and doubles (CCSD) is coupled to a Stieltjes imaging technique in order to describe the photoionization cross section of atoms and molecules, in the spirit of a similar procedure recently proposed by Averbukh and co-workers within the Algebraic Diagrammatic Construction approach. Pilot results are reported for the atoms He, Ne, and Ar and for the molecules H{sub 2}, H{sub 2}O, NH{sub 3}, HF, CO, and CO{sub 2}.

  14. STATISTICAL ANALYSIS OF DWARF GALAXIES AND THEIR GLOBULAR CLUSTERS IN THE LOCAL VOLUME

    SciTech Connect

    Chattopadhyay, Tanuka; Karmakar, Pradip; Sharina, Margarita

    2010-11-20

    Although morphological classification of dwarf galaxies into early and late types can account for some of their origin and characteristics, this does not aid the study of their formation mechanism. Thus an objective classification using principal component analysis together with K means cluster analysis of these dwarf galaxies and their globular clusters (GCs) is carried out to overcome this problem. It is found that the classification of dwarf galaxies in the local volume is irrespective of their morphological indices. The more massive (M{sub V0} < -13.7) galaxies evolve through self-enrichment and harbor dynamically less evolved younger GCs, whereas fainter galaxies (M{sub V0} > - 13.7) are influenced by their environment in the star formation process.

  15. A comparative study of local galaxy clusters - II. X-ray and SZ scaling relations

    NASA Astrophysics Data System (ADS)

    Rozo, E.; Evrard, A. E.; Rykoff, E. S.; Bartlett, J. G.

    2014-02-01

    We compare cluster scaling relations published for three different samples selected via X-ray and Sunyaev-Zel'dovich (SZ) signatures. We find tensions driven mainly by two factors: (i) systematic differences in the X-ray cluster observables used to derive the scaling relations and (ii) uncertainty in the modelling of how the gas mass of galaxy clusters scales with total mass. All scaling relations are in agreement after accounting for these two effects. We describe a multivariate scaling model that enables a fully self-consistent treatment of multiple observational catalogues in the presence of property covariance and apply this formalism when interpreting published results. The corrections due to scatter and observable covariance can be significant. For instance, our predicted YSZ-LX scaling relation differs from that derived using the naive `plug in' method by ≈25 per cent. Finally, we test the mass normalization for each of the X-ray data sets we consider by applying a space density consistency test: we compare the observed ROSAT-ESO Flux-Limited X-ray (REFLEX) luminosity function to expectations from published LX-M relations convolved with the mass function for a Wilkinson Microwave Anisotropy Probe 7 flat Λ cold dark matter model.

  16. Robust kernelized local information fuzzy C-means clustering for brain magnetic resonance image segmentation.

    PubMed

    Elazab, Ahmed; AbdulAzeem, Yousry M; Wu, Shiqian; Hu, Qingmao

    2016-03-17

    Brain tissue segmentation from magnetic resonance (MR) images is an importance task for clinical use. The segmentation process becomes more challenging in the presence of noise, grayscale inhomogeneity, and other image artifacts. In this paper, we propose a robust kernelized local information fuzzy C-means clustering algorithm (RKLIFCM). It incorporates local information into the segmentation process (both grayscale and spatial) for more homogeneous segmentation. In addition, the Gaussian radial basis kernel function is adopted as a distance metric to replace the standard Euclidean distance. The main advantages of the new algorithm are: efficient utilization of local grayscale and spatial information, robustness to noise, ability to preserve image details, free from any parameter initialization, and with high speed as it runs on image histogram. We compared the proposed algorithm with 7 soft clustering algorithms that run on both image histogram and image pixels to segment brain MR images. Experimental results demonstrate that the proposed RKLIFCM algorithm is able to overcome the influence of noise and achieve higher segmentation accuracy with low computational complexity.

  17. Local properties of the reconnecting magnetotail current sheet: a statistical study using Geotail and Cluster

    NASA Astrophysics Data System (ADS)

    Genestreti, K. J.; Fuselier, S. A.; Goldstein, J.; Nagai, T.; Eastwood, J. P.

    2015-12-01

    Reconnection in the near-Earth magnetotail occurs most frequently duskward of midnight. This asymmetry is evident in the spatial occurrence of both reconnection- driven transients and of the reconnection site itself. From a number of studies that investigated the cause of this asymmetry, there are two main, opposing explanations: 'global' and 'local'. The 'global' explanation is that asymmetric ionospheric conductance is the cause. The 'local' explanation points to the asymmetric thinning of the plasma sheet as the cause of the asymmetry. A number of observational studies have identified the effects of the 'local' and 'global' controls of the properties of the non-reconnecting magnetotail current sheet. In this study, we analyze the properties of the reconnecting current sheet (in the vicinity of an active reconnection site) using in situ data from Geotail and Cluster encounters with the reconnection site. Our method is specific to the geometry of the current sheet crossing for either Geotail or Cluster. For all of our observations, we approximate the current sheet with the Harris model. For Cluster data, we use a modified curlometer technique to analyze the strength and profile of the ion-scale current. For Geotail data, our analysis technique depends on whether the encounter with the reconnection site was driven by the motion of the current sheet or the motion of the spacecraft. We compare the properties of the current sheet for reconnection observations near the dawn and dusk flanks (infrequent) with those for reconnection observations on the near-midnight duskside (more frequent). Initial results are presented.

  18. AGN Clustering in the Local Universe: An Unbiased Picture from Swift-BAT

    SciTech Connect

    Cappelluti, N.; Ajello, M.; Burlon, D.; Krumpe, M.; Miyaji, T.; Bonoli, S.; Greiner, J.; /Garching, Max Planck Inst., MPE

    2011-08-11

    We present the clustering measurement of hard X-ray selected AGN in the local Universe. We used a sample of 199 sources spectroscopically confirmed detected by Swift-BAT in its 15-55 keV all-sky survey. We measured the real space projected auto-correlation function and detected a signal significant on projected scales lower than 200 Mpc/h. We measured a correlation length of r{sub 0} = 5.56{sup +0.49}{sub -0.43} Mpc/h and a slope {gamma} = 1.64{sup -0.08}{sub -0.07}. We also measured the auto-correlation function of Tyep I and Type II AGN and found higher correlation length for Type I AGN. We have a marginal evidence of luminosity dependent clustering of AGN, as we detected a larger correlation length of luminous AGN than that of low luminosity sources. The corresponding typical host DM halo masses of Swift-BAT are {approx} log(M{sub DMH) {approx} 12-14 h{sup -1}M/M{sub {circle_dot}} which is the typical mass of a galaxy group. We estimated that the local AGN population has a typical lifetime {tau}{sub AGN} {approx}0.7 Gyr, it is powered by SMBH with mass M{sub BH} {approx}1-10x10{sup 8} M{sub {circle_dot}} and accreting with very low efficiency, log({epsilon}){approx}-2.0>. We also conclude that local AGN galaxies are typically red-massive galaxies with stellar mass of the order 2-80x10{sup 10} h{sup -1}M{sub {circle_dot}}. We compared our results with clustering predictions of merger-driven AGN triggering models and found a good agreement.

  19. Galaxy cluster X-ray luminosity scaling relations from a representative local sample (REXCESS)

    NASA Astrophysics Data System (ADS)

    Pratt, G. W.; Croston, J. H.; Arnaud, M.; Böhringer, H.

    2009-05-01

    We examine the X-ray luminosity scaling relations of 31 nearby galaxy clusters from the Representative XMM-Newton Cluster Structure Survey (REXCESS). The objects are selected only in X-ray luminosity, optimally sampling the cluster luminosity function. Temperatures range from 2 to 9 keV, and there is no bias toward any particular morphological type. To reduce measurement scatter we extract pertinent values in an aperture corresponding to R500, estimated using the tight correlation between YX (the product of gas mass and temperature) and total mass. The data exhibit power law relations between bolometric X-ray luminosity and temperature, YX and total mass, all with slopes that are significantly steeper than self-similar expectations. We examine the possible causes for the steepening, finding that structural variations have little effect and that the primary driver appears to be a systematic variation of the gas content with mass. Scatter about the relations is dominated in all cases by the presence of cool cores. The natural logarithmic scatter about the raw X-ray luminosity-temperature relation is about 70 per cent, and about the X-ray luminosity-YX relation it is 40 per cent. Systems with more morphological substructure show similar scatter about scaling relations than clusters with less substructure, due to the preponderance of cool core systems in the regular cluster subsample. Cool core and morphologically disturbed systems occupy distinct regions in the residual space with respect to the best fitting mean relation, the former lying systematically at the high luminosity side, the latter lying systematically at the low luminosity side. Simple exclusion of the central regions serves to reduce the scatter about the scaling relations by more than a factor of two. The scatter reduces by a similar amount with the use of the central gas density as a third parameter. Using YX as a total mass proxy, we derive a Malmquist bias-corrected local luminosity-mass relation and

  20. Capturing local atomic environment dependence of activation barriers in metals using cluster expansion models

    NASA Astrophysics Data System (ADS)

    Kulkarni, Nimish; Chatterjee, Abhijit

    2016-10-01

    It is well known that surface diffusion in metals can proceed via multiple mechanisms, such as hop, exchange and other types of concerted moves. However, the manner in which kinetic rates associated with a mechanism can depend sensitively on local atomic environment is relatively less understood. We describe recent attempts in our research group to capture the atomic environment dependence using the cluster expansion model (CEM). In particular, we focus on hop and exchange moves at the (001) surface in homoepitaxy, and show that while CEM can work remarkably well in most cases, it can sometimes provide inaccurate predictions for concerted moves.

  1. WaterWorld, a spatial hydrological model applied at scales from local to global: key challenges to local application

    NASA Astrophysics Data System (ADS)

    Burke, Sophia; Mulligan, Mark

    2017-04-01

    WaterWorld is a widely used spatial hydrological policy support system. The last user census indicates regular use by 1029 institutions across 141 countries. A key feature of WaterWorld since 2001 is that it comes pre-loaded with all of the required data for simulation anywhere in the world at a 1km or 1 ha resolution. This means that it can be easily used, without specialist technical ability, to examine baseline hydrology and the impacts of scenarios for change or management interventions to support policy formulation, hence its labelling as a policy support system. WaterWorld is parameterised by an extensive global gridded database of more than 600 variables, developed from many sources, since 1998, the so-called simTerra database. All of these data are available globally at 1km resolution and some variables (terrain, land cover, urban areas, water bodies) are available globally at 1ha resolution. If users have access to better data than is pre-loaded, they can upload their own data. WaterWorld is generally applied at the national or basin scale at 1km resolution, or locally (for areas of <10,000km2) at 1ha resolution, though continental (1km resolution) and global (10km resolution) applications are possible so it is a model with local to global applications. WaterWorld requires some 140 maps to run including monthly climate data, land cover and use, terrain, population, water bodies and more. Whilst publically-available terrain and land cover data are now well developed for local scale application, climate and land use data remain a challenge, with most global products being available at 1km or 10km resolution or worse, which is rather coarse for local application. As part of the EartH2Observe project we have used WFDEI (WATCH Forcing Data methodology applied to ERA-Interim data) at 1km resolution to provide an alternative input to WaterWorld's preloaded climate data. Here we examine the impacts of that on key hydrological outputs: water balance, water quality

  2. Localization of phonons in mass-disordered alloys: A typical medium dynamical cluster approach

    NASA Astrophysics Data System (ADS)

    Mondal, Wasim Raja; Vidhyadhiraja, N. S.; Berlijn, T.; Moreno, Juana; Jarrell, M.

    2017-07-01

    The effect of disorder on lattice vibrational modes has been a topic of interest for several decades. In this work, we employ a Green's function based approach, namely, the dynamical cluster approximation (DCA), to investigate phonons in mass-disordered systems. Detailed benchmarks with previous exact calculations are used to validate the method in a wide parameter space. An extension of the method, namely, the typical medium DCA (TMDCA), is used to study Anderson localization of phonons in three dimensions. We show that, for binary isotopic disorder, lighter impurities induce localized modes beyond the bandwidth of the host system, while heavier impurities lead to a partial localization of the low-frequency acoustic modes. For a uniform (box) distribution of masses, the physical spectrum is shown to develop long tails comprising mostly localized modes. The mobility edge separating extended and localized modes, obtained through the TMDCA, agrees well with results from the transfer matrix method. A reentrance behavior of the mobility edge with increasing disorder is found that is similar to, but somewhat more pronounced than, the behavior in disordered electronic systems. Our work establishes a computational approach, which recovers the thermodynamic limit, is versatile and computationally inexpensive, to investigate lattice vibrations in disordered lattice systems.

  3. Localization of phonons in mass-disordered alloys: A typical medium dynamical cluster approach

    DOE PAGES

    Mondal, Wasim Raja; Vidhyadhiraja, N. S.; Berlijn, Tom; ...

    2017-07-20

    The effect of disorder on lattice vibrational modes has been a topic of interest for several decades. In this work, we employ a Green's function based approach, namely, the dynamical cluster approximation (DCA), to investigate phonons in mass-disordered systems. Detailed benchmarks with previous exact calculations are used to validate the method in a wide parameter space. An extension of the method, namely, the typical medium DCA (TMDCA), is used to study Anderson localization of phonons in three dimensions. We show that, for binary isotopic disorder, lighter impurities induce localized modes beyond the bandwidth of the host system, while heavier impuritiesmore » lead to a partial localization of the low-frequency acoustic modes. For a uniform (box) distribution of masses, the physical spectrum is shown to develop long tails comprising mostly localized modes. The mobility edge separating extended and localized modes, obtained through the TMDCA, agrees well with results from the transfer matrix method. A reentrance behavior of the mobility edge with increasing disorder is found that is similar to, but somewhat more pronounced than, the behavior in disordered electronic systems. As a result, our work establishes a computational approach, which recovers the thermodynamic limit, is versatile and computationally inexpensive, to investigate lattice vibrations in disordered lattice systems.« less

  4. Goal oriented soil mapping: applying modern methods supported by local knowledge: A review

    NASA Astrophysics Data System (ADS)

    Pereira, Paulo; Brevik, Eric; Oliva, Marc; Estebaranz, Ferran; Depellegrin, Daniel; Novara, Agata; Cerda, Artemi; Menshov, Oleksandr

    2017-04-01

    In the recent years the amount of soil data available increased importantly. This facilitated the production of better and accurate maps, important for sustainable land management (Pereira et al., 2017). Despite these advances, the human knowledge is extremely important to understand the natural characteristics of the landscape. The knowledge accumulated and transmitted generation after generation is priceless, and should be considered as a valuable data source for soil mapping and modelling. The local knowledge and wisdom can complement the new advances in soil analysis. In addition, farmers are the most interested in the participation and incorporation of their knowledge in the models, since they are the end-users of the study that soil scientists produce. Integration of local community's vision and understanding about nature is assumed to be an important step to the implementation of decision maker's policies. Despite this, many challenges appear regarding the integration of local and scientific knowledge, since in some cases there is no spatial correlation between folk and scientific classifications, which may be attributed to the different cultural variables that influence local soil classification. The objective of this work is to review how modern soil methods incorporated local knowledge in their models. References Pereira, P., Brevik, E., Oliva, M., Estebaranz, F., Depellegrin, D., Novara, A., Cerda, A., Menshov, O. (2017) Goal Oriented soil mapping: applying modern methods supported by local knowledge. In: Pereira, P., Brevik, E., Munoz-Rojas, M., Miller, B. (Eds.) Soil mapping and process modelling for sustainable land use management (Elsevier Publishing House) ISBN: 9780128052006

  5. Deep Gemini/GMOS imaging of an extremely isolated globular cluster in the Local Group

    NASA Astrophysics Data System (ADS)

    Mackey, A. D.; Ferguson, A. M. N.; Irwin, M. J.; Martin, N. F.; Huxor, A. P.; Tanvir, N. R.; Chapman, S. C.; Ibata, R. A.; Lewis, G. F.; McConnachie, A. W.

    2010-01-01

    We report on deep imaging of a remote M31 globular cluster, MGC1, obtained with Gemini/GMOS. Our colour-magnitude diagram for this object extends ~5 mag below the tip of the red-giant branch and exhibits features consistent with an ancient metal-poor stellar population, including a long, well-populated horizontal branch. The red-giant branch locus suggests MGC1 has a metal abundance [M/H] ~ -2.3. We measure the distance to MGC1 and find that it lies ~160 kpc in front of M31 with a distance modulus μ = 23.95 +/- 0.06. Combined with its large projected separation of Rp = 117 kpc from M31, this implies a deprojected radius of Rgc = 200 +/- 20 kpc, rendering it the most isolated known globular cluster in the Local Group by some considerable margin. We construct a radial brightness profile for MGC1 and show that it is both centrally compact and rather luminous, with MV = -9.2. Remarkably, the cluster profile shows no evidence for a tidal limit and we are able to trace it to a radius of at least 450 pc, and possibly as far as ~900 pc. The profile exhibits a power-law fall-off with exponent γ = -2.5, breaking to γ = -3.5 in its outermost parts. This core-halo structure is broadly consistent with expectations derived from numerical models, and suggests that MGC1 has spent many gigayears in isolation.

  6. Meteor tracking via local pattern clustering in spatio-temporal domain

    NASA Astrophysics Data System (ADS)

    Kukal, Jaromír.; Klimt, Martin; Švihlík, Jan; Fliegel, Karel

    2016-09-01

    Reliable meteor detection is one of the crucial disciplines in astronomy. A variety of imaging systems is used for meteor path reconstruction. The traditional approach is based on analysis of 2D image sequences obtained from a double station video observation system. Precise localization of meteor path is difficult due to atmospheric turbulence and other factors causing spatio-temporal fluctuations of the image background. The proposed technique performs non-linear preprocessing of image intensity using Box-Cox transform as recommended in our previous work. Both symmetric and asymmetric spatio-temporal differences are designed to be robust in the statistical sense. Resulting local patterns are processed by data whitening technique and obtained vectors are classified via cluster analysis and Self-Organized Map (SOM).

  7. Comparative studies for different proximity potentials applied to large cluster radioactivity of nuclei

    NASA Astrophysics Data System (ADS)

    Zhang, G. L.; Yao, Y. J.; Guo, M. F.; Pan, M.; Zhang, G. X.; Liu, X. X.

    2016-07-01

    Half-lives of large cluster radioactivity of even-even nuclei calculated by using fourteen proximity potentials are compared to experimental data. The results show that the results of BASS77 and Denisov potentials are most agreeable with the experimental data. Christensen and Winther 1976 potential gives the smallest half-lives. In comparison with the distributions of different proximity potentials and the distributions of total potentials when the values of total potentials are more than the released energy Qc, it is found that at the small distances the large differences of proximity potentials do not affect the calculation results. The different distributions of total potentials affect the penetration probability of large cluster radioactivity, and then affect the half-life of large cluster radioactivity.

  8. The iron-sulfur cluster of pyruvate formate-lyase activating enzyme in whole cells: cluster interconversion and a valence-localized [4Fe-4S]2+ state.

    PubMed

    Yang, Jian; Naik, Sunil G; Ortillo, Danilo O; García-Serres, Ricardo; Li, Meng; Broderick, William E; Huynh, Boi Hanh; Broderick, Joan B

    2009-10-06

    Pyruvate formate-lyase activating enzyme (PFL-AE) catalyzes the generation of a catalytically essential glycyl radical on pyruvate formate-lyase (PFL). Purified PFL-AE contains an oxygen-sensitive, labile [4Fe-4S] cluster that undergoes cluster interconversions in vitro, with only the [4Fe-4S](+) cluster state being catalytically active. Such cluster interconversions could play a role in regulating the activity of PFL-AE, and thus of PFL, in response to oxygen levels in vivo. Here we report a Mossbauer investigation on whole cells overexpressing PFL-AE following incubation under aerobic and/or anaerobic conditions and provide evidence that PFL-AE undergoes cluster interconversions in vivo. After 2 h aerobic induction of PFL-AE expression, approximately 44% of the total iron is present in [4Fe-4S](2+) clusters, 6% in [2Fe-2S](2+) clusters, and the remainder as noncluster Fe(III) (29%) and Fe(II) (21%) species. Subsequent anaerobic incubation of the culture results in approximately 75% of the total iron being present as [4Fe-4S](2+) clusters, with no detectable [2Fe-2S](2+). Ensuing aerobic incubation of the culture converts the iron species nearly back to the original composition (42% [4Fe-4S](2+), 10% [2Fe-2S](2+), 19% Fe(III), and 29% Fe(II)). The results provide evidence for changes in cluster composition of PFL-AE in response to the redox state of the cell. Furthermore, the Mossbauer spectra reveal that the [4Fe-4S](2+) cluster of PFL-AE in whole cells contains a valence-localized Fe(III)Fe(II) pair which has not been previously observed in the purified enzyme. Addition of certain small molecules containing adenosyl moieties, including 5'-deoxyadenosine, AMP, ADP, and methylthioadenosine, to purified PFL-AE reproduces the valence-localized state of the [4Fe-4S](2+) cluster. It is speculated that the [4Fe-4S](2+) cluster of PFL-AE in whole cells may be coordinated by a small molecule, probably AMP, and that such coordination may protect this labile cluster from

  9. Clustering-based pattern recognition applied to chemical recognition using SAW array signals

    SciTech Connect

    Osbourn, G.C.; Bartholomew, J.W.; Frye, G.C.; Ricco, A.J.

    1994-05-01

    We present a new patter recognition (PR) technique for chemical identification using arrays of microsensors. The technique relies on a new empirical approach to k-dimensional cluster analysis which incorporates measured human visual perceptions of difficult 2- dimensional clusters. The method can handle nonlinear SAW array data, detects both unexpected (outlier) and unreliable array responses, and has no user-adjustable parameters. We use this technique to guide the development of arrays of thin-film-coated SAW (Surface Acoustic Wave) devices that produce optimal PR performance for distinguishing a variety of volatile organic compounds, organophosphonates and water.

  10. Locally applied valproate enhances survival in rats after neocortical treatment with tetanus toxin and cobalt chloride.

    PubMed

    Altenmüller, Dirk-Matthias; Hebel, Jonas M; Rassner, Michael P; Volz, Silvanie; Freiman, Thomas M; Feuerstein, Thomas J; Zentner, Josef

    2013-01-01

    In neocortical epilepsies not satisfactorily responsive to systemic antiepileptic drug therapy, local application of antiepileptic agents onto the epileptic focus may enhance treatment efficacy and tolerability. We describe the effects of focally applied valproate (VPA) in a newly emerging rat model of neocortical epilepsy induced by tetanus toxin (TeT) plus cobalt chloride (CoCl₂). In rats, VPA (n = 5) or sodium chloride (NaCl) (n = 5) containing polycaprolactone (PCL) implants were applied onto the right motor cortex treated before with a triple injection of 75 ng TeT plus 15 mg CoCl₂. Video-EEG monitoring was performed with intracortical depth electrodes. All rats randomized to the NaCl group died within one week after surgery. In contrast, the rats treated with local VPA survived significantly longer (P < 0.01). In both groups, witnessed deaths occurred in the context of seizures. At least 3/4 of the rats surviving the first postoperative day developed neocortical epilepsy with recurrent spontaneous seizures. The novel TeT/CoCl₂ approach targets at a new model of neocortical epilepsy in rats and allows the investigation of local epilepsy therapy strategies. In this vehicle-controlled study, local application of VPA significantly enhanced survival in rats, possibly by focal antiepileptic or antiepileptogenic mechanisms.

  11. Valley and channel networks extraction based on local topographic curvature and k-means clustering of contours

    NASA Astrophysics Data System (ADS)

    Hooshyar, Milad; Wang, Dingbao; Kim, Seoyoung; Medeiros, Stephen C.; Hagen, Scott C.

    2016-10-01

    A method for automatic extraction of valley and channel networks from high-resolution digital elevation models (DEMs) is presented. This method utilizes both positive (i.e., convergent topography) and negative (i.e., divergent topography) curvature to delineate the valley network. The valley and ridge skeletons are extracted using the pixels' curvature and the local terrain conditions. The valley network is generated by checking the terrain for the existence of at least one ridge between two intersecting valleys. The transition from unchannelized to channelized sections (i.e., channel head) in each first-order valley tributary is identified independently by categorizing the corresponding contours using an unsupervised approach based on k-means clustering. The method does not require a spatially constant channel initiation threshold (e.g., curvature or contributing area). Moreover, instead of a point attribute (e.g., curvature), the proposed clustering method utilizes the shape of contours, which reflects the entire cross-sectional profile including possible banks. The method was applied to three catchments: Indian Creek and Mid Bailey Run in Ohio and Feather River in California. The accuracy of channel head extraction from the proposed method is comparable to state-of-the-art channel extraction methods.

  12. Localizing text in scene images by boundary clustering, stroke segmentation, and string fragment classification.

    PubMed

    Yi, Chucai; Tian, Yingli

    2012-09-01

    In this paper, we propose a novel framework to extract text regions from scene images with complex backgrounds and multiple text appearances. This framework consists of three main steps: boundary clustering (BC), stroke segmentation, and string fragment classification. In BC, we propose a new bigram-color-uniformity-based method to model both text and attachment surface, and cluster edge pixels based on color pairs and spatial positions into boundary layers. Then, stroke segmentation is performed at each boundary layer by color assignment to extract character candidates. We propose two algorithms to combine the structural analysis of text stroke with color assignment and filter out background interferences. Further, we design a robust string fragment classification based on Gabor-based text features. The features are obtained from feature maps of gradient, stroke distribution, and stroke width. The proposed framework of text localization is evaluated on scene images, born-digital images, broadcast video images, and images of handheld objects captured by blind persons. Experimental results on respective datasets demonstrate that the framework outperforms state-of-the-art localization algorithms.

  13. Experience of BESIII data production with local cluster and distributed computing model

    NASA Astrophysics Data System (ADS)

    Deng, Z. Y.; Li, W. D.; Lin, L.; Liu, H. M.; Nicholson, C.; Sun, Y. Z.; Zhang, X. M.; Zhemchugov, A.

    2012-12-01

    The BES III detector is a new spectrometer which works on the upgraded high-luminosity collider, BEPCII. The BES III experiment studies physics in the tau-charm energy region from 2 GeV to 4.6 GeV . From 2009 to 2011, BEPCII has produced 106M ψ(2S) events, 225M J/ψ events, 2.8 fb-1 ψ(3770) data, and 500 pb-1 data at 4.01 GeV. All the data samples were processed successfully and many important physics results have been achieved based on these samples. Doing data production correctly and efficiently with limited CPU and storage resources is a big challenge. This paper will describe the implementation of the experiment-specific data production for BESIII in detail, including data calibration with event-level parallel computing model, data reconstruction, inclusive Monte Carlo generation, random trigger background mixing and multi-stream data skimming. Now, with the data sample increasing rapidly, there is a growing demand to move from solely using a local cluster to a more distributed computing model. A distributed computing environment is being set up and expected to go into production use in 2012. The experience of BESIII data production, both with a local cluster and with a distributed computing model, is presented here.

  14. Degree of initial hole localization/delocalization in ionized water clusters.

    PubMed

    Pieniazek, Piotr A; Sundstrom, Eric J; Bradforth, Stephen E; Krylov, Anna I

    2009-04-23

    The electronic structure of ionized bulk liquid water presents a number of theoretical challenges. Not the least of these is the realization that the detailed geometry of the hydrogen bonding network is expected to have a strong effect on the electronic couplings between water molecules and thus the degree of delocalization of the initially ionized system. This problem is approached from a cluster perspective where a high-level coupled cluster description of the electronic structure is still possible. Building on the work and methodology developed for the water dimer cation [J. Phys. Chem. A 2008, 112, 6159], the character and spectrum of electronic states of the water hole and their evolution from the dimer into higher clusters is presented. As the time evolution of the initially formed hole can in principle be followed by the system's transient absorption spectrum, the state spacings and transition strengths are computed. An analysis involving Dyson orbitals is applied and shows a partially delocalized nature of states. The issue of conformation disorder in the hydrogen bonding geometry is addressed for the water dimer cation.

  15. HUBBLE SPACE TELESCOPE SNAPSHOT SEARCH FOR PLANETARY NEBULAE IN GLOBULAR CLUSTERS OF THE LOCAL GROUP

    SciTech Connect

    Bond, Howard E.

    2015-04-15

    Single stars in ancient globular clusters (GCs) are believed incapable of producing planetary nebulae (PNs), because their post-asymptotic-giant-branch evolutionary timescales are slower than the dissipation timescales for PNs. Nevertheless, four PNs are known in Galactic GCs. Their existence likely requires more exotic evolutionary channels, including stellar mergers and common-envelope binary interactions. I carried out a snapshot imaging search with the Hubble Space Telescope (HST) for PNs in bright Local Group GCs outside the Milky Way. I used a filter covering the 5007 Å nebular emission line of [O iii], and another one in the nearby continuum, to image 66 GCs. Inclusion of archival HST frames brought the total number of extragalactic GCs imaged at 5007 Å to 75, whose total luminosity slightly exceeds that of the entire Galactic GC system. I found no convincing PNs in these clusters, aside from one PN in a young M31 cluster misclassified as a GC, and two PNs at such large angular separations from an M31 GC that membership is doubtful. In a ground-based spectroscopic survey of 274 old GCs in M31, Jacoby et al. found three candidate PNs. My HST images of one of them suggest that the [O iii] emission actually arises from ambient interstellar medium rather than a PN; for the other two candidates, there are broadband archival UV HST images that show bright, blue point sources that are probably the PNs. In a literature search, I also identified five further PN candidates lying near old GCs in M31, for which follow-up observations are necessary to confirm their membership. The rates of incidence of PNs are similar, and small but nonzero, throughout the GCs of the Local Group.

  16. Module Cluster: TTP-005.00 (GSC). Applied Behavior Analysis Principles.

    ERIC Educational Resources Information Center

    Brent, George; And Others

    This module cluster enables (a) students to operationally define various classroom behaviors; (b) define and utilize behavioral principles; and (c) correctly employ measurement methods which facilitate information gathering, monitoring, and management of academic and/or "problem" classroom behaviors. It contains modules in the following ten areas:…

  17. Applying the Logic of Sample Surveys to Qualitative Case Studies: The Case Cluster Method.

    ERIC Educational Resources Information Center

    McClintock, Charles C.; And Others

    1979-01-01

    While preserving the distinctive features of the case study, the case cluster method employs replicable sampling and, if desired, quantitative measurement procedures to complement qualitative analysis. It creates units of analysis that are based on theory and that have meaning for the actors and observers of the case. (Author/IRT)

  18. Profiling Local Optima in K-Means Clustering: Developing a Diagnostic Technique

    ERIC Educational Resources Information Center

    Steinley, Douglas

    2006-01-01

    Using the cluster generation procedure proposed by D. Steinley and R. Henson (2005), the author investigated the performance of K-means clustering under the following scenarios: (a) different probabilities of cluster overlap; (b) different types of cluster overlap; (c) varying samples sizes, clusters, and dimensions; (d) different multivariate…

  19. Profiling Local Optima in K-Means Clustering: Developing a Diagnostic Technique

    ERIC Educational Resources Information Center

    Steinley, Douglas

    2006-01-01

    Using the cluster generation procedure proposed by D. Steinley and R. Henson (2005), the author investigated the performance of K-means clustering under the following scenarios: (a) different probabilities of cluster overlap; (b) different types of cluster overlap; (c) varying samples sizes, clusters, and dimensions; (d) different multivariate…

  20. Estimating the Impacts of Local Policy Innovation: The Synthetic Control Method Applied to Tropical Deforestation

    PubMed Central

    Sills, Erin O.; Herrera, Diego; Kirkpatrick, A. Justin; Brandão, Amintas; Dickson, Rebecca; Hall, Simon; Pattanayak, Subhrendu; Shoch, David; Vedoveto, Mariana; Young, Luisa; Pfaff, Alexander

    2015-01-01

    Quasi-experimental methods increasingly are used to evaluate the impacts of conservation interventions by generating credible estimates of counterfactual baselines. These methods generally require large samples for statistical comparisons, presenting a challenge for evaluating innovative policies implemented within a few pioneering jurisdictions. Single jurisdictions often are studied using comparative methods, which rely on analysts’ selection of best case comparisons. The synthetic control method (SCM) offers one systematic and transparent way to select cases for comparison, from a sizeable pool, by focusing upon similarity in outcomes before the intervention. We explain SCM, then apply it to one local initiative to limit deforestation in the Brazilian Amazon. The municipality of Paragominas launched a multi-pronged local initiative in 2008 to maintain low deforestation while restoring economic production. This was a response to having been placed, due to high deforestation, on a federal “blacklist” that increased enforcement of forest regulations and restricted access to credit and output markets. The local initiative included mapping and monitoring of rural land plus promotion of economic alternatives compatible with low deforestation. The key motivation for the program may have been to reduce the costs of blacklisting. However its stated purpose was to limit deforestation, and thus we apply SCM to estimate what deforestation would have been in a (counterfactual) scenario of no local initiative. We obtain a plausible estimate, in that deforestation patterns before the intervention were similar in Paragominas and the synthetic control, which suggests that after several years, the initiative did lower deforestation (significantly below the synthetic control in 2012). This demonstrates that SCM can yield helpful land-use counterfactuals for single units, with opportunities to integrate local and expert knowledge and to test innovations and permutations on

  1. Estimating the Impacts of Local Policy Innovation: The Synthetic Control Method Applied to Tropical Deforestation.

    PubMed

    Sills, Erin O; Herrera, Diego; Kirkpatrick, A Justin; Brandão, Amintas; Dickson, Rebecca; Hall, Simon; Pattanayak, Subhrendu; Shoch, David; Vedoveto, Mariana; Young, Luisa; Pfaff, Alexander

    2015-01-01

    Quasi-experimental methods increasingly are used to evaluate the impacts of conservation interventions by generating credible estimates of counterfactual baselines. These methods generally require large samples for statistical comparisons, presenting a challenge for evaluating innovative policies implemented within a few pioneering jurisdictions. Single jurisdictions often are studied using comparative methods, which rely on analysts' selection of best case comparisons. The synthetic control method (SCM) offers one systematic and transparent way to select cases for comparison, from a sizeable pool, by focusing upon similarity in outcomes before the intervention. We explain SCM, then apply it to one local initiative to limit deforestation in the Brazilian Amazon. The municipality of Paragominas launched a multi-pronged local initiative in 2008 to maintain low deforestation while restoring economic production. This was a response to having been placed, due to high deforestation, on a federal "blacklist" that increased enforcement of forest regulations and restricted access to credit and output markets. The local initiative included mapping and monitoring of rural land plus promotion of economic alternatives compatible with low deforestation. The key motivation for the program may have been to reduce the costs of blacklisting. However its stated purpose was to limit deforestation, and thus we apply SCM to estimate what deforestation would have been in a (counterfactual) scenario of no local initiative. We obtain a plausible estimate, in that deforestation patterns before the intervention were similar in Paragominas and the synthetic control, which suggests that after several years, the initiative did lower deforestation (significantly below the synthetic control in 2012). This demonstrates that SCM can yield helpful land-use counterfactuals for single units, with opportunities to integrate local and expert knowledge and to test innovations and permutations on policies

  2. Cluster-search based monitoring of local earthquakes in SeisComP3

    NASA Astrophysics Data System (ADS)

    Roessler, D.; Becker, J.; Ellguth, E.; Herrnkind, S.; Weber, B.; Henneberger, R.; Blanck, H.

    2016-12-01

    We present a new cluster-search based SeisComP3 module for locating local and regional earthquakes in real time. Real-time earthquake monitoring systems such as SeisComP3 provide the backbones for earthquake early warning (EEW), tsunami early warning (TEW) and the rapid assessment of natural and induced seismicity. For any earthquake monitoring system fast and accurate event locations are fundamental determining the reliability and the impact of further analysis. SeisComP3 in the OpenSource version includes a two-stage detector for picking P waves and a phase associator for locating earthquakes based on P-wave detections. scanloc is a more advanced earthquake location program developed by gempa GmbH with seamless integration into SeisComP3. scanloc performs advanced cluster search to discriminate earthquakes occurring closely in space and time and makes additional use of S-wave detections. It has proven to provide fast and accurate earthquake locations at local and regional distances where it outperforms the base SeisComP3 tools. We demonstrate the performance of scanloc for monitoring induced seismicity as well as local and regional earthquakes in different tectonic regimes including subduction, spreading and intra-plate regions. In particular we present examples and catalogs from real-time monitoring of earthquake in Northern Chile based on data from the IPOC network by GFZ German Research Centre for Geosciences for the recent years. Depending on epicentral distance and data transmission, earthquake locations are available within a few seconds after origin time when using scanloc. The association of automatic S-wave detections provides a better constraint on focal depth.

  3. Development of a guide to applying precaution in local public health

    PubMed Central

    Hau, Monica; Cole, Donald; Vanderlinden, Loren; MacFarlane, Ronald; Mee, Carol; Archbold, Josephine; Campbell, Monica

    2014-01-01

    Purpose: The precautionary principle (PP) urges actions to prevent harm even in the face of scientific uncertainty. Members of Toronto Public Health (TPH) sought guidance on applying precaution. Methods: We searched five bibliographic databases (yield 60 articles from 1996 to 2009 and 8 from 2009 to 2011) and Google (yield 11 gray literature sources) for material relevant to local public health. From these sources, we extracted questions until saturation was reached (n = 55). We applied these questions retrospectively to eight case studies where TPH felt precaution was applied. We ranked questions for their importance in applying precaution. Results: Our final guide included 35 questions in five domains: context, assessment, alternative interventions, implementation, and monitoring and evaluation. Importance rankings varied across cases, but the role of stakeholders in driving precautionary action was consistent. Monitoring and evaluation components could have been strengthened across cases. Conclusion: The TPH guide can assist municipal environmental health practitioners in applying precaution in a more transparent manner. PMID:24999853

  4. Evidence of toroidally localized turbulence with applied 3D fields in the DIII-D tokamak

    SciTech Connect

    Wilcox, R. S.; Shafer, M. W.; Ferraro, N. M.; McKee, G. R.; Zeng, L.; Rhodes, T. L.; Canik, J. M.; Paz-Soldan, C.; Nazikian, R.; Unterberg, E. A.

    2016-09-21

    New evidence indicates that there is significant 3D variation in density fluctuations near the boundary of weakly 3D tokamak plasmas when resonant magnetic perturbations are applied to suppress transient edge instabilities. The increase in fluctuations is concomitant with an increase in the measured density gradient, suggesting that this toroidally localized gradient increase could be a mechanism for turbulence destabilization in localized flux tubes. Two-fluid magnetohydrodynamic simulations find that, although changes to the magnetic field topology are small, there is a significant 3D variation of the density gradient within the flux surfaces that is extended along field lines. This modeling agrees qualitatively with the measurements. The observed gradient and fluctuation asymmetries are proposed as a mechanism by which global profile gradients in the pedestal could be relaxed due to a local change in the 3D equilibrium. In conclusion, these processes may play an important role in pedestal and scrape-off layer transport in ITER and other future tokamak devices with small applied 3D fields.

  5. Evidence of Toroidally Localized Turbulence with Applied 3D Fields in the DIII-D Tokamak.

    PubMed

    Wilcox, R S; Shafer, M W; Ferraro, N M; McKee, G R; Zeng, L; Rhodes, T L; Canik, J M; Paz-Soldan, C; Nazikian, R; Unterberg, E A

    2016-09-23

    New evidence indicates that there is significant 3D variation in density fluctuations near the boundary of weakly 3D tokamak plasmas when resonant magnetic perturbations are applied to suppress transient edge instabilities. The increase in fluctuations is concomitant with an increase in the measured density gradient, suggesting that this toroidally localized gradient increase could be a mechanism for turbulence destabilization in localized flux tubes. Two-fluid magnetohydrodynamic simulations find that, although changes to the magnetic field topology are small, there is a significant 3D variation of the density gradient within the flux surfaces that is extended along field lines. This modeling agrees qualitatively with the measurements. The observed gradient and fluctuation asymmetries are proposed as a mechanism by which global profile gradients in the pedestal could be relaxed due to a local change in the 3D equilibrium. These processes may play an important role in pedestal and scrape-off layer transport in ITER and other future tokamak devices with small applied 3D fields.

  6. Evidence of toroidally localized turbulence with applied 3D fields in the DIII-D tokamak

    SciTech Connect

    Wilcox, R. S.; Shafer, M. W.; Ferraro, N. M.; McKee, G. R.; Zeng, L.; Rhodes, T. L.; Canik, J. M.; Paz-Soldan, C.; Nazikian, R.; Unterberg, E. A.

    2016-09-21

    New evidence indicates that there is significant 3D variation in density fluctuations near the boundary of weakly 3D tokamak plasmas when resonant magnetic perturbations are applied to suppress transient edge instabilities. The increase in fluctuations is concomitant with an increase in the measured density gradient, suggesting that this toroidally localized gradient increase could be a mechanism for turbulence destabilization in localized flux tubes. Two-fluid magnetohydrodynamic simulations find that, although changes to the magnetic field topology are small, there is a significant 3D variation of the density gradient within the flux surfaces that is extended along field lines. This modeling agrees qualitatively with the measurements. The observed gradient and fluctuation asymmetries are proposed as a mechanism by which global profile gradients in the pedestal could be relaxed due to a local change in the 3D equilibrium. In conclusion, these processes may play an important role in pedestal and scrape-off layer transport in ITER and other future tokamak devices with small applied 3D fields.

  7. Evidence of toroidally localized turbulence with applied 3D fields in the DIII-D tokamak

    DOE PAGES

    Wilcox, R. S.; Shafer, M. W.; Ferraro, N. M.; ...

    2016-09-21

    New evidence indicates that there is significant 3D variation in density fluctuations near the boundary of weakly 3D tokamak plasmas when resonant magnetic perturbations are applied to suppress transient edge instabilities. The increase in fluctuations is concomitant with an increase in the measured density gradient, suggesting that this toroidally localized gradient increase could be a mechanism for turbulence destabilization in localized flux tubes. Two-fluid magnetohydrodynamic simulations find that, although changes to the magnetic field topology are small, there is a significant 3D variation of the density gradient within the flux surfaces that is extended along field lines. This modeling agreesmore » qualitatively with the measurements. The observed gradient and fluctuation asymmetries are proposed as a mechanism by which global profile gradients in the pedestal could be relaxed due to a local change in the 3D equilibrium. In conclusion, these processes may play an important role in pedestal and scrape-off layer transport in ITER and other future tokamak devices with small applied 3D fields.« less

  8. A novel method for discovering local spatial clusters of genomic regions with functional relationships from DNA contact maps

    PubMed Central

    Hu, Xihao; Shi, Christina Huan; Yip, Kevin Y.

    2016-01-01

    Motivation: The three-dimensional structure of genomes makes it possible for genomic regions not adjacent in the primary sequence to be spatially proximal. These DNA contacts have been found to be related to various molecular activities. Previous methods for analyzing DNA contact maps obtained from Hi-C experiments have largely focused on studying individual interactions, forming spatial clusters composed of contiguous blocks of genomic locations, or classifying these clusters into general categories based on some global properties of the contact maps. Results: Here, we describe a novel computational method that can flexibly identify small clusters of spatially proximal genomic regions based on their local contact patterns. Using simulated data that highly resemble Hi-C data obtained from real genome structures, we demonstrate that our method identifies spatial clusters that are more compact than methods previously used for clustering genomic regions based on DNA contact maps. The clusters identified by our method enable us to confirm functionally related genomic regions previously reported to be spatially proximal in different species. We further show that each genomic region can be assigned a numeric affinity value that indicates its degree of participation in each local cluster, and these affinity values correlate quantitatively with DNase I hypersensitivity, gene expression, super enhancer activities and replication timing in a cell type specific manner. We also show that these cluster affinity values can precisely define boundaries of reported topologically associating domains, and further define local sub-domains within each domain. Availability and implementation: The source code of BNMF and tutorials on how to use the software to extract local clusters from contact maps are available at http://yiplab.cse.cuhk.edu.hk/bnmf/. Contact: kevinyip@cse.cuhk.edu.hk Supplementary information: Supplementary data are available at Bioinformatics online. PMID:27307607

  9. Supporting breastfeeding In Local Communities (SILC) in Victoria, Australia: a cluster randomised controlled trial

    PubMed Central

    McLachlan, Helen L; Forster, Della A; Amir, Lisa H; Cullinane, Meabh; Shafiei, Touran; Watson, Lyndsey F; Ridgway, Lael; Cramer, Rhian L; Small, Rhonda

    2016-01-01

    Objectives Breastfeeding has significant health benefits for mothers and infants. Despite recommendations from the WHO, by 6 months of age 40% of Australian infants are receiving no breast milk. Increased early postpartum breastfeeding support may improve breastfeeding maintenance. 2 community-based interventions to increase breastfeeding duration in local government areas (LGAs) in Victoria, Australia, were implemented and evaluated. Design 3-arm cluster randomised trial. Setting LGAs in Victoria, Australia. Participants LGAs across Victoria with breastfeeding initiation rates below the state average and > 450 births/year were eligible for inclusion. The LGA was the unit of randomisation, and maternal and child health centres in the LGAs comprised the clusters. Interventions Early home-based breastfeeding support by a maternal and child health nurse (home visit, HV) with or without access to a community-based breastfeeding drop-in centre (HV+drop-in). Main outcome measures The proportion of infants receiving ‘any’ breast milk at 3, 4 and 6 months (women's self-report). Findings 4 LGAs were randomised to the comparison arm and provided usual care (n=41 clusters; n=2414 women); 3 to HV (n=32 clusters; n=2281 women); and 3 to HV+drop-in (n=26 clusters; 2344 women). There was no difference in breastfeeding at 4 months in either HV (adjusted OR 1.04; 95% CI 0.84 to 1.29) or HV+drop-in (adjusted OR 0.92; 95% CI 0.78 to 1.08) compared with the comparison arm, no difference at 3 or 6 months, nor in any LGA in breastfeeding before and after the intervention. Some issues were experienced with intervention protocol fidelity. Conclusions Early home-based and community-based support proved difficult to implement. Interventions to increase breastfeeding in complex community settings require sufficient time and partnership building for successful implementation. We cannot conclude that additional community-based support is ineffective in improving breastfeeding

  10. User Activity Recognition in Smart Homes Using Pattern Clustering Applied to Temporal ANN Algorithm

    PubMed Central

    Bourobou, Serge Thomas Mickala; Yoo, Younghwan

    2015-01-01

    This paper discusses the possibility of recognizing and predicting user activities in the IoT (Internet of Things) based smart environment. The activity recognition is usually done through two steps: activity pattern clustering and activity type decision. Although many related works have been suggested, they had some limited performance because they focused only on one part between the two steps. This paper tries to find the best combination of a pattern clustering method and an activity decision algorithm among various existing works. For the first step, in order to classify so varied and complex user activities, we use a relevant and efficient unsupervised learning method called the K-pattern clustering algorithm. In the second step, the training of smart environment for recognizing and predicting user activities inside his/her personal space is done by utilizing the artificial neural network based on the Allen’s temporal relations. The experimental results show that our combined method provides the higher recognition accuracy for various activities, as compared with other data mining classification algorithms. Furthermore, it is more appropriate for a dynamic environment like an IoT based smart home. PMID:26007738

  11. User Activity Recognition in Smart Homes Using Pattern Clustering Applied to Temporal ANN Algorithm.

    PubMed

    Bourobou, Serge Thomas Mickala; Yoo, Younghwan

    2015-05-21

    This paper discusses the possibility of recognizing and predicting user activities in the IoT (Internet of Things) based smart environment. The activity recognition is usually done through two steps: activity pattern clustering and activity type decision. Although many related works have been suggested, they had some limited performance because they focused only on one part between the two steps. This paper tries to find the best combination of a pattern clustering method and an activity decision algorithm among various existing works. For the first step, in order to classify so varied and complex user activities, we use a relevant and efficient unsupervised learning method called the K-pattern clustering algorithm. In the second step, the training of smart environment for recognizing and predicting user activities inside his/her personal space is done by utilizing the artificial neural network based on the Allen's temporal relations. The experimental results show that our combined method provides the higher recognition accuracy for various activities, as compared with other data mining classification algorithms. Furthermore, it is more appropriate for a dynamic environment like an IoT based smart home.

  12. Applying a 2D based CAD scheme for detecting micro-calcification clusters using digital breast tomosynthesis images: an assessment

    NASA Astrophysics Data System (ADS)

    Park, Sang Cheol; Zheng, Bin; Wang, Xiao-Hui; Gur, David

    2008-03-01

    Digital breast tomosynthesis (DBT) has emerged as a promising imaging modality for screening mammography. However, visually detecting micro-calcification clusters depicted on DBT images is a difficult task. Computer-aided detection (CAD) schemes for detecting micro-calcification clusters depicted on mammograms can achieve high performance and the use of CAD results can assist radiologists in detecting subtle micro-calcification clusters. In this study, we compared the performance of an available 2D based CAD scheme with one that includes a new grouping and scoring method when applied to both projection and reconstructed DBT images. We selected a dataset involving 96 DBT examinations acquired on 45 women. Each DBT image set included 11 low dose projection images and a varying number of reconstructed image slices ranging from 18 to 87. In this dataset 20 true-positive micro-calcification clusters were visually detected on the projection images and 40 were visually detected on the reconstructed images, respectively. We first applied the CAD scheme that was previously developed in our laboratory to the DBT dataset. We then tested a new grouping method that defines an independent cluster by grouping the same cluster detected on different projection or reconstructed images. We then compared four scoring methods to assess the CAD performance. The maximum sensitivity level observed for the different grouping and scoring methods were 70% and 88% for the projection and reconstructed images with a maximum false-positive rate of 4.0 and 15.9 per examination, respectively. This preliminary study demonstrates that (1) among the maximum, the minimum or the average CAD generated scores, using the maximum score of the grouped cluster regions achieved the highest performance level, (2) the histogram based scoring method is reasonably effective in reducing false-positive detections on the projection images but the overall CAD sensitivity is lower due to lower signal-to-noise ratio

  13. Improving the Robustness of Local Network Alignment: Design and Extensive Assessment of a Markov Clustering-Based Approach.

    PubMed

    Mina, Marco; Guzzi, Pietro Hiram

    2014-01-01

    The analysis of protein behavior at the network level had been applied to elucidate the mechanisms of protein interaction that are similar in different species. Published network alignment algorithms proved to be able to recapitulate known conserved modules and protein complexes, and infer new conserved interactions confirmed by wet lab experiments. In the meantime, however, a plethora of continuously evolving protein-protein interaction (PPI) data sets have been developed, each featuring different levels of completeness and reliability. For instance, algorithms performance may vary significantly when changing the data set used in their assessment. Moreover, existing papers did not deeply investigate the robustness of alignment algorithms. For instance, some algorithms performances vary significantly when changing the data set used in their assessment. In this work, we design an extensive assessment of current algorithms discussing the robustness of the results on the basis of input networks. We also present AlignMCL, a local network alignment algorithm based on an improved model of alignment graph and Markov Clustering. AlignMCL performs better than other state-of-the-art local alignment algorithms over different updated data sets. In addition, AlignMCL features high levels of robustness, producing similar results regardless the selected data set.

  14. Comparison of explicitly correlated local coupled-cluster methods with various choices of virtual orbitals.

    PubMed

    Krause, Christine; Werner, Hans-Joachim

    2012-06-07

    Explicitly correlated local coupled-cluster (LCCSD-F12) methods with pair natural orbitals (PNOs), orbital specific virtual orbitals (OSVs), and projected atomic orbitals (PAOs) are compared. In all cases pair-specific virtual subspaces (domains) are used, and the convergence of the correlation energy as a function of the domain sizes is studied. Furthermore, the performance of the methods for reaction energies of 52 reactions involving 58 small and medium sized molecules is investigated. It is demonstrated that for all choices of virtual orbitals much smaller domains are needed in the explicitly correlated methods than without the explicitly correlated terms, since the latter correct a large part of the domain error, as found previously. For PNO-LCCSD-F12 with VTZ-F12 basis sets on the average only 20 PNOs per pair are needed to obtain reaction energies with a root mean square deviation of less than 1 kJ mol(-1) from complete basis set estimates. With OSVs or PAOs at least 4 times larger domains are needed for the same accuracy. A new hybrid method that combines the advantages of the OSV and PNO methods is proposed and tested. While in the current work the different local methods are only simulated using a conventional CCSD program, the implications for low-order scaling local implementations of the various methods are discussed.

  15. Dissecting the Biochemical and Transcriptomic Effects of a Locally Applied Heat Treatment on Developing Cabernet Sauvignon Grape Berries.

    PubMed

    Lecourieux, Fatma; Kappel, Christian; Pieri, Philippe; Charon, Justine; Pillet, Jérémy; Hilbert, Ghislaine; Renaud, Christel; Gomès, Eric; Delrot, Serge; Lecourieux, David

    2017-01-01

    Reproductive development of grapevine and berry composition are both strongly influenced by temperature. To date, the molecular mechanisms involved in grapevine berries response to high temperatures are poorly understood. Unlike recent data that addressed the effects on berry development of elevated temperatures applied at the whole plant level, the present work particularly focuses on the fruit responses triggered by direct exposure to heat treatment (HT). In the context of climate change, this work focusing on temperature effect at the microclimate level is of particular interest as it can help to better understand the consequences of leaf removal (a common viticultural practice) on berry development. HT (+ 8°C) was locally applied to clusters from Cabernet Sauvignon fruiting cuttings at three different developmental stages (middle green, veraison and middle ripening). Samples were collected 1, 7, and 14 days after treatment and used for metabolic and transcriptomic analyses. The results showed dramatic and specific biochemical and transcriptomic changes in heat exposed berries, depending on the developmental stage and the stress duration. When applied at the herbaceous stage, HT delayed the onset of veraison. Heating also strongly altered the berry concentration of amino acids and organic acids (e.g., phenylalanine, γ-aminobutyric acid and malate) and decreased the anthocyanin content at maturity. These physiological alterations could be partly explained by the deep remodeling of transcriptome in heated berries. More than 7000 genes were deregulated in at least one of the nine experimental conditions. The most affected processes belong to the categories "stress responses," "protein metabolism" and "secondary metabolism," highlighting the intrinsic capacity of grape berries to perceive HT and to build adaptive responses. Additionally, important changes in processes related to "transport," "hormone" and "cell wall" might contribute to the postponing of veraison

  16. Brain vascular image segmentation based on fuzzy local information C-means clustering

    NASA Astrophysics Data System (ADS)

    Hu, Chaoen; Liu, Xia; Liang, Xiao; Hui, Hui; Yang, Xin; Tian, Jie

    2017-02-01

    Light sheet fluorescence microscopy (LSFM) is a powerful optical resolution fluorescence microscopy technique which enables to observe the mouse brain vascular network in cellular resolution. However, micro-vessel structures are intensity inhomogeneity in LSFM images, which make an inconvenience for extracting line structures. In this work, we developed a vascular image segmentation method by enhancing vessel details which should be useful for estimating statistics like micro-vessel density. Since the eigenvalues of hessian matrix and its sign describes different geometric structure in images, which enable to construct vascular similarity function and enhance line signals, the main idea of our method is to cluster the pixel values of the enhanced image. Our method contained three steps: 1) calculate the multiscale gradients and the differences between eigenvalues of Hessian matrix. 2) In order to generate the enhanced microvessels structures, a feed forward neural network was trained by 2.26 million pixels for dealing with the correlations between multi-scale gradients and the differences between eigenvalues. 3) The fuzzy local information c-means clustering (FLICM) was used to cluster the pixel values in enhance line signals. To verify the feasibility and effectiveness of this method, mouse brain vascular images have been acquired by a commercial light-sheet microscope in our lab. The experiment of the segmentation method showed that dice similarity coefficient can reach up to 85%. The results illustrated that our approach extracting line structures of blood vessels dramatically improves the vascular image and enable to accurately extract blood vessels in LSFM images.

  17. Extracellular engagement of ADAM12 induces clusters of invadopodia with localized ectodomain shedding activity.

    PubMed

    Albrechtsen, Reidar; Stautz, Dorte; Sanjay, Archana; Kveiborg, Marie; Wewer, Ulla M

    2011-01-15

    Invadopodia are dynamic actin structures at the cell surface that degrade extracellular matrix and act as sites of signal transduction. The biogenesis of invadopodia, including the mechanisms regulating their formation, composition, and turnover is not entirely understood. Here, we demonstrate that antibody ligation of ADAM12, a transmembrane disintegrin and metalloprotease, resulted in the rapid accumulation of invadopodia with extracellular matrix-degrading capacity in epithelial cells expressing the αvβ3 integrin and active c-Src kinase. The induction of invadopodia clusters required an intact c-Src interaction site in the ADAM12 cytoplasmic domain, but was independent of the catalytic activity of ADAM12. Caveolin-1 and transmembrane protease MMP14/MT1-MMP were both present in the ADAM12-induced clusters of invadopodia, and cholesterol depletion prevented their formation, suggesting that lipid-raft microdomains are involved in the process. Importantly, our data demonstrate that ADAM12-mediated ectodomain shedding of epidermal growth factor receptor ligands can occur within these invadopodia. Such localized growth factor signalling offers an interesting novel biological concept highly relevant to the properties of carcinoma cells, which often show upregulated ADAM12 and β3 integrin expression, together with high levels of c-Src kinase activity.

  18. Predictable nonwandering localization of covariant Lyapunov vectors and cluster synchronization in scale-free networks of chaotic maps.

    PubMed

    Kuptsov, Pavel V; Kuptsova, Anna V

    2014-09-01

    Covariant Lyapunov vectors for scale-free networks of Hénon maps are highly localized. We revealed two mechanisms of the localization related to full and phase cluster synchronization of network nodes. In both cases the localization nodes remain unaltered in the course of the dynamics, i.e., the localization is nonwandering. Moreover, this is predictable: The localization nodes are found to have specific dynamical and topological properties and they can be found without computing of the covariant vectors. This is an example of explicit relations between the system topology, its phase-space dynamics, and the associated tangent-space dynamics of covariant Lyapunov vectors.

  19. Cluster analysis applied to velocity, attenuation and gravity tomography: the case of Campanian district volcanoes (southern italy)

    NASA Astrophysics Data System (ADS)

    Troiano, A.; di Giuseppe, M.; Petrillo, Z.; de Siena, L.; Siniscalchi, A.; Berrino, G.

    2009-12-01

    The interpretation of the results of seismic velocity, attenuation and gravity inversion are usually based on the qualitative observation and comparison of the different tomographic images. A promising tool to jointly interpret tomographic models based on different parameters resides in the application of statistical classification methods, such as the k-means clustering method, which minimizes the logic distance among each group of observations having homogeneous physical properties and maximizes the same quantity between groups. The correlation between the models is subsequently examined and significant classes (volumes of high correlation) are identified. Such technique is able to spatially clusterize the zones having similar characteristics in a statistical sense. Each zone is finally identified by the barycenter (centroid) of the corresponding cluster. Although the Vp velocity, Qp and Qs attenuation structures and density anomalies of Mt.Vesuvius and Campi Flegrei area Italy, have been already interpreted, to obtain a quantitative interpretation gathered in a unified model consistent with the entire dataset, a cluster analysis was applied to these models. This analysis permitted to define a simplified model of the volcanic complexes in terms of the independent geophysical parameters, characterized by sharp and well defined boundaries . This post-interpretation technique on one hand is largely far from being quantitative in terms of rock lithology , but in the same time is fast, easy and useful to retrieve the main patterns of the investigated structures. In other words, k-means cluster analysis may act as a bridge between qualitative interpretation (based on the visual comparison of the different structures obtained with different tomography techniques) and more quantitative approaches (based on the joint inversion of multiple attributes).

  20. [Acute intravenous toxicity to mice calculations on the basis local regression models in superoverlapping clusters (LRMSC)].

    PubMed

    Raevskiĭ, O A; Grigor'ev, V Iu; Liplavskaia, E A; Vorts, A P

    2012-01-01

    Modeling of quantitative structure--activity relationships between physicochemical descriptors of organic chemicals and their acute intravenous toxicity in mice have been presented. This approach includes three steps: structure-similarity chemicals selection for every chemical-of-interest (clusterization); construction of quantitative structure--toxicity models for every cluster (without including of chemical-of-interest); application of obtained QSAR equations for chemical-of-interest toxicity estimation. This approach has been applied for acute intravenous toxicity calculations of 10241 organic chemicals. For 7759 chemicals which has enough quantity of structural neighbours with the Tanimoto index (Tc) on the level 0.30 and over, a standard deviation of calculation vs. experimental log(1/LD50) values is equal to 0.51 at the estimation of experimental determination on the level 0.50. The results of calculations isn't so good for remain chemicals (approximately 24%). It is connect with absence of sufficient number of structure similarity neighbours. It's assumed this QSAR approach can be useful for activity and toxicity prediction of chemicals large sets.

  1. Minimum polarizability principle applied to lowest energy isomers of some gaseous all-metal clusters.

    PubMed

    Mang, Chao-Yong; Zhao, Xia; He, Li-Xian; Liu, Cai-Ping; Wu, Ke-Chen

    2008-02-21

    In comparison with the minimum energy criterion as an indicator of the most stable state, the minimum polarizability and maximum hardness principles have been examined to describe the relative stability of various isomers of nine gaseous all-metal clusters M4X- (Cu4Na-, Cu4Li-, Al4Cu-, Ag4Li-, Au4Li-, Ag4Na-, Au4Na-, Al4Ag-, Al4Au-) on the basis of MP2 calculations. In these species, there are two lowest energy isomers with near isoenergy that sometimes make it very difficult to determine which of them is more stable when we depend only on the minimum energy criterion. According to the minimum polarizability principle, however, the square-pyramidal structure is always more stable than the planar isomer at various computational levels, which was also confirmed by the results from the minimum energy principle that sometimes requires higher computational precision. Thus, there is an indication that, at least for our present cluster system, the minimum polarizability principle is less dependent on the computational levels compared to the minimum energy principle.

  2. Drift tube soft-landing for the production and characterization of materials: Applied to Cu clusters

    NASA Astrophysics Data System (ADS)

    Davila, Stephen J.; Birdwell, David O.; Verbeck, Guido F.

    2010-03-01

    We have recently developed a soft-landing (SL) instrument that is capable of depositing ions onto substrates for preparative and developmental research of new materials using a laser ablation source. This instrument was designed with a custom drift tube and a split-ring ion optic for the isolation of selected ions. The drift tube allows for the separation and thermalization of ions formed after laser ablation through collisions with an inert bath gas. These collisions allow the ions to be landed at energies below 1 eV onto substrates. The split-ring ion optic is capable of directing ions toward the detector or a landing substrate for selected components. Experiments will be shown ablating Cu using an Nd:YAG (1064 and 532 nm) for cluster formation and landing onto a muscovite (mica) surface. The laser ablation of Cu in 8 Torr of He gas gives a spectrum that contains multiple peaks corresponding to Cun, CunOm clusters, and their corresponding isomers. Atomic force microscopy and drift tube measurements were performed to characterize the performance characteristics of the instrument.

  3. Spectral clustering applied for dynamic contrast-enhanced MR analysis of time-intensity curves.

    PubMed

    Tartare, Guillaume; Hamad, Denis; Azahaf, Mustapha; Puech, Philippe; Betrouni, Nacim

    2014-12-01

    Dynamic contrast-enhanced (DCE)-magnetic resonance imaging (MRI) represents an emerging method for the prediction of biomarker responses in cancer. However, DCE images remain difficult to analyze and interpret. Although pharmacokinetic approaches, which involve multi-step processes, can provide a general framework for the interpretation of these data, they are still too complex for robust and accurate implementation. Therefore, statistical data analysis techniques were recently suggested as another valid interpretation strategy for DCE-MRI. In this context, we propose a spectral clustering approach for the analysis of DCE-MRI time-intensity signals. This graph theory-based method allows for the grouping of signals after spatial transformation. Subsequently, these data clusters can be labeled following comparison to arterial signals. Here, we have performed experiments with simulated (i.e., generated via pharmacokinetic modeling) and clinical (i.e., obtained from patients scanned during prostate cancer diagnosis) data sets in order to demonstrate the feasibility and applicability of this kind of unsupervised and non-parametric approach.

  4. The UV-optical colour dependence of galaxy clustering in the local universe

    NASA Astrophysics Data System (ADS)

    Loh, Yeong-Shang; Rich, R. Michael; Heinis, Sébastien; Scranton, Ryan; Mallery, Ryan P.; Salim, Samir; Martin, D. Christopher; Wyder, Ted; Arnouts, Stéphane; Barlow, Tom A.; Forster, Karl; Friedman, Peter G.; Morrissey, Patrick; Neff, Susan G.; Schiminovich, David; Seibert, Mark; Bianchi, Luciana; Donas, Jose; Heckman, Timothy M.; Lee, Young-Wook; Madore, Barry F.; Milliard, Bruno; Szalay, Alex S.; Welsh, Barry Y.

    2010-09-01

    We measure the UV-optical colour dependence of galaxy clustering in the local Universe. Using the clean separation of the red and blue sequences made possible by the NUV - r colour-magnitude diagram, we segregate the galaxies into red, blue and intermediate `green' classes. We explore the clustering as a function of this segregation by removing the dependence on luminosity and by excluding edge-on galaxies as a means of a non-model dependent veto of highly extincted galaxies. We find that ξ(rp, π) for both red and green galaxies shows strong redshift-space distortion on small scales - the `finger-of-God' effect, with green galaxies having a lower amplitude than is seen for the red sequence, and the blue sequence showing almost no distortion. On large scales, ξ(rp, π) for all three samples show the effect of large-scale streaming from coherent infall. On scales of 1h-1Mpc < rp < 10h-1Mpc, the projected auto-correlation function wp(rp) for red and green galaxies fits a power law with slope γ ~ 1.93 and amplitude r0 ~ 7.5 and 5.3, compared with γ ~ 1.75 and r0 ~ 3.9 h-1 Mpc for blue sequence galaxies. Compared to the clustering of a fiducial L* galaxy, the red, green and blue have a relative bias of 1.5, 1.1 and 0.9, respectively. The wp(rp) for blue galaxies display an increase in convexity at ~ 1 h-1 Mpc, with an excess of large-scale clustering. Our results suggest that the majority of blue galaxies are likely central galaxies in less massive haloes, while red and green galaxies have larger satellite fractions, and preferentially reside in virialized structures. If blue sequence galaxies migrate to the red sequence via processes like mergers or quenching that take them through the green valley, such a transformation may be accompanied by a change in environment in addition to any change in luminosity and colour.

  5. Local clustering in breast, lung and colorectal cancer in Long Island, New York

    PubMed Central

    Jacquez, Geoffrey M; Greiling, Dunrie A

    2003-01-01

    Background Analyses of spatial disease patterns usually employ a univariate approach that uses one technique to identify disease clusters. Because different methods are sensitive to different aspects of spatial pattern, an approach employing a battery of techniques is expected to describe geographic variation in human health more fully. This two-part study employs a multi-method approach to elucidate geographic variation in cancer incidence in Long Island, New York, and to evaluate spatial association with air-borne toxics. This first paper uses the local Moran statistic to identify cancer hotspots and spatial outliers. We evaluated the geographic distributions of breast cancer in females and colorectal and lung cancer in males and females in Nassau, Queens, and Suffolk counties, New York, USA. We calculated standardized morbidity ratios (SMR values) from New York State Department of Health (NYSDOH) data. Results We identified significant local clusters of high and low SMR and significant spatial outliers for each cancer-gender combination. We then compared our results with the study conducted by NYSDOH using Kulldorff's spatial scan statistic. We identified patterns on a smaller spatial scale with different cluster shapes than the NYSDOH analysis did, a consequence of different statistical methods and analysis scale. Conclusion This is a methodological and comparative study to evaluate whether there is substantial benefit added by using a variety of techniques for geographic pattern detection at different spatial scales. We located significant spatial pattern in cancer morbidity in Nassau, Queens, and Suffolk counties. These results broadly agree with the results of other studies that used different techniques, but differ in specifics. The differences in our results and that of the NYSDOH underscore the need for an exploratory, integrative, and multi-scalar approach to assessing geographic patterns of disease, as different methods identify different patterns. We

  6. The impact of a locally applied vibrating device on outpatient venipuncture in children.

    PubMed

    Whelan, Hilary M; Kunselman, Allen R; Thomas, Neal J; Moore, Jeffrey; Tamburro, Robert F

    2014-10-01

    To assess the impact of a locally applied vibrating device on outpatient venipuncture in children. A retrospective review of survey data collected prospectively as part of a quality improvement project. Both patients and phlebotomists were surveyed. The sample consisted of 64 children aged 4 to 18 years (29 prior to the implementation of the vibrating device and 35 afterward) and 7 phlebotomists. Prior to the use of the vibrating device, 17 children (59%) indicated that they wished something had been done to decrease venipuncture pain. Eighty percent of the cohort that used the vibrating device indicated that they would like it used for future procedures. Children with previous venipuncture experiences appeared to benefit most from use of the vibrating technique. The phlebotomists reported that vibration made the procedure easier in 81% of the cases; none reported that it complicated the procedure. Locally applied vibration appears to be a well-accepted technique to minimize pediatric venipuncture discomfort that may facilitate completion of the procedure. © The Author(s) 2014.

  7. Noncontact Measurement of the Local Mechanical Properties of Living Cells Using Pressure Applied via a Pipette

    PubMed Central

    Sánchez, Daniel; Johnson, Nick; Li, Chao; Novak, Pavel; Rheinlaender, Johannes; Zhang, Yanjun; Anand, Uma; Anand, Praveen; Gorelik, Julia; Frolenkov, Gregory I.; Benham, Christopher; Lab, Max; Ostanin, Victor P.; Schäffer, Tilman E.; Klenerman, David; Korchev, Yuri E.

    2008-01-01

    Mechanosensitivity in living biological tissue is a study area of increasing importance, but investigative tools are often inadequate. We have developed a noncontact nanoscale method to apply quantified positive and negative force at defined positions to the soft responsive surface of living cells. The method uses applied hydrostatic pressure (0.1–150 kPa) through a pipette, while the pipette-sample separation is kept constant above the cell surface using ion conductance based distance feedback. This prevents any surface contact, or contamination of the pipette, allowing repeated measurements. We show that we can probe the local mechanical properties of living cells using increasing pressure, and hence measure the nanomechanical properties of the cell membrane and the underlying cytoskeleton in a variety of cells (erythrocytes, epithelium, cardiomyocytes and neurons). Because the cell surface can first be imaged without pressure, it is possible to relate the mechanical properties to the local cell topography. This method is well suited to probe the nanomechanical properties and mechanosensitivity of living cells. PMID:18515369

  8. Locally applied nerve growth factor enhances bone consolidation in a rabbit model of mandibular distraction osteogenesis.

    PubMed

    Wang, Lei; Zhou, Shuxia; Liu, Baolin; Lei, Delin; Zhao, Yinghua; Lu, Chao; Tan, Aixing

    2006-12-01

    Distraction osteogenesis is widely used in treating deformities, defects, and fractures of both long bones and craniofacial bones. Demands for acceleration of bone consolidation are increased in distraction osteogenesis. Nerve growth factor (NGF) can enhance innervation and bone regeneration in a fracture model and stimulate differentiation of osteoblastic cells. In this study, we tested the ability of locally applied NGF to enhance bone regeneration in a rabbit model of mandibular distraction osteogenesis. Twenty rabbits underwent bilateral distraction osteogenesis with a rate of 0.5 mm per 12 h. Two times 0.04 mg human NGFbeta (hNGFbeta) in buffer was injected into the callus after distraction. The contralateral side received placebo injections. Rabbits were euthanized at consolidation times of 14 and 28 days. Specimens were subjected to radiography, callus dimensions measurement, mechanical testing, and bone histological and histomorphometric analysis. The maximum load, bone volume/total volume, mineral apposition rate of the 1st to 11th day, and mineralized bone percentage were significantly higher in the hNGFbeta side at 14 and 28 days (p<0.05). The data indicate that locally applied hNGFbeta can accelerate callus maturation and may be an option to shorten the consolidation period in distraction osteogenesis.

  9. 20 CFR 666.310 - What levels of performance apply to the indicators of performance in local areas?

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... indicators of performance in local areas? 666.310 Section 666.310 Employees' Benefits EMPLOYMENT AND TRAINING... Local Measures of Performance § 666.310 What levels of performance apply to the indicators of... Governor and reach agreement on the local levels of performance for each indicator identified under §...

  10. 20 CFR 666.310 - What levels of performance apply to the indicators of performance in local areas?

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... indicators of performance in local areas? 666.310 Section 666.310 Employees' Benefits EMPLOYMENT AND TRAINING... Local Measures of Performance § 666.310 What levels of performance apply to the indicators of... Governor and reach agreement on the local levels of performance for each indicator identified under §...

  11. Paired MEG data set source localization using recursively applied and projected (RAP) MUSIC.

    PubMed

    Ermer, J J; Mosher, J C; Huang, M; Leahy, R M

    2000-09-01

    An important class of experiments in functional brain mapping involves collecting pairs of data corresponding to separate "Task" and "Control" conditions. The data are then analyzed to determine what activity occurs during the Task experiment but not in the Control. Here we describe a new method for processing paired magnetoencephalographic (MEG) data sets using our recursively applied and projected multiple signal classification (RAP-MUSIC) algorithm. In this method the signal subspace of the Task data is projected against the orthogonal complement of the Control data signal subspace to obtain a subspace which describes spatial activity unique to the Task. A RAP-MUSIC localization search is then performed on this projected data to localize the sources which are active in the Task but not in the Control data. In addition to dipolar sources, effective blocking of more complex sources, e.g., multiple synchronously activated dipoles or synchronously activated distributed source activity, is possible since these topographies are well-described by the Control data signal subspace. Unlike previously published methods, the proposed method is shown to be effective in situations where the time series associated with Control and Task activity possess significant cross correlation. The method also allows for straightforward determination of the estimated time series of the localized target sources. A multiepoch MEG simulation and a phantom experiment are presented to demonstrate the ability of this method to successfully identify sources and their time series in the Task data.

  12. Applying Best Practices to Florida Local Government Retrofit Programs, Central Florida (Fact Sheet)

    SciTech Connect

    Not Available

    2014-03-01

    In some communities, local government and non-profit entities have funds to purchase and renovate distressed, foreclosed homes for resale in the affordable housing market. Numerous opportunities to improve whole house energy efficiency are inherent in these comprehensive renovations. BA-PIRC worked together in a multi-year field study making recommendations in individual homes, meanwhile compiling improvement costs, projected energy savings, practical challenges, and labor force factors surrounding common energy-related renovation measures. The field study, Phase 1 of this research, resulted in a set of best practices appropriate to the current labor pool and market conditions in central Florida to achieve projected annual energy savings of 15-30% and higher. This report describes Phase 2 of the work where researchers worked with a local government partner to implement and refine the "current best practices". A simulation study was conducted to characterize savings potential under three sets of conditions representing varying replacement needs for energy-related equipment and envelope components. The three scenarios apply readily to the general remodeling industry as for renovation of foreclosed homes for the affordable housing market. Our new local government partner, the City of Melbourne, implemented the best practices in a community-scale renovation program that included ten homes in 2012. ​

  13. Selection of key ambient particulate variables for epidemiological studies - applying cluster and heatmap analyses as tools for data reduction.

    PubMed

    Gu, Jianwei; Pitz, Mike; Breitner, Susanne; Birmili, Wolfram; von Klot, Stephanie; Schneider, Alexandra; Soentgen, Jens; Reller, Armin; Peters, Annette; Cyrys, Josef

    2012-10-01

    The success of epidemiological studies depends on the use of appropriate exposure variables. The purpose of this study is to extract a relatively small selection of variables characterizing ambient particulate matter from a large measurement data set. The original data set comprised a total of 96 particulate matter variables that have been continuously measured since 2004 at an urban background aerosol monitoring site in the city of Augsburg, Germany. Many of the original variables were derived from measured particle size distribution (PSD) across the particle diameter range 3 nm to 10 μm, including size-segregated particle number concentration, particle length concentration, particle surface concentration and particle mass concentration. The data set was complemented by integral aerosol variables. These variables were measured by independent instruments, including black carbon, sulfate, particle active surface concentration and particle length concentration. It is obvious that such a large number of measured variables cannot be used in health effect analyses simultaneously. The aim of this study is a pre-screening and a selection of the key variables that will be used as input in forthcoming epidemiological studies. In this study, we present two methods of parameter selection and apply them to data from a two-year period from 2007 to 2008. We used the agglomerative hierarchical cluster method to find groups of similar variables. In total, we selected 15 key variables from 9 clusters which are recommended for epidemiological analyses. We also applied a two-dimensional visualization technique called "heatmap" analysis to the Spearman correlation matrix. 12 key variables were selected using this method. Moreover, the positive matrix factorization (PMF) method was applied to the PSD data to characterize the possible particle sources. Correlations between the variables and PMF factors were used to interpret the meaning of the cluster and the heatmap analyses

  14. Unified cluster expansion method applied to the configurational thermodynamics of cubic Ti1-xAlxN

    NASA Astrophysics Data System (ADS)

    Alling, Björn; Ruban, Andrei; Karimi, Ayat; Hultman, Lars; Abrikosov, Igor

    2012-02-01

    We study the thermodynamics of cubic Ti1-xAlxN using a unified cluster expansion approach for the alloy problem [1]. The purely configurational part of the alloy Hamiltonian is expanded in terms of concentration and volume-dependent effective cluster interactions. By separate expansions of the chemical fixed lattice, and local lattice relaxation terms of the ordering energies, we demonstrate how the screened generalized perturbation method can be fruitfully combined with a concentration-dependent Connolly-Williams cluster expansion method, getting the best out of both two schemes that are traditionally used separately. Utilizing the obtained Hamiltonian in Monte Carlo simulations we access the free energy of Ti1-xAlxN alloys and construct the isostructural phase diagram. The results show striking similarities with the previously obtained mean-field results: The metastable c-TiAlN is subject to coherent spinodal decomposition over a large part of the concentration range, e.g., from x 0.33 at 2000 K. [4pt] [1] B. Alling, A. V. Ruban, A. Karimi, L. Hultman, and I. A. Abrikosov, PHYSICAL REVIEW B 83, 104203 (2011)

  15. A Smartphone Indoor Localization Algorithm Based on WLAN Location Fingerprinting with Feature Extraction and Clustering

    PubMed Central

    Luo, Junhai; Fu, Liang

    2017-01-01

    With the development of communication technology, the demand for location-based services is growing rapidly. This paper presents an algorithm for indoor localization based on Received Signal Strength (RSS), which is collected from Access Points (APs). The proposed localization algorithm contains the offline information acquisition phase and online positioning phase. Firstly, the AP selection algorithm is reviewed and improved based on the stability of signals to remove useless AP; secondly, Kernel Principal Component Analysis (KPCA) is analyzed and used to remove the data redundancy and maintain useful characteristics for nonlinear feature extraction; thirdly, the Affinity Propagation Clustering (APC) algorithm utilizes RSS values to classify data samples and narrow the positioning range. In the online positioning phase, the classified data will be matched with the testing data to determine the position area, and the Maximum Likelihood (ML) estimate will be employed for precise positioning. Eventually, the proposed algorithm is implemented in a real-world environment for performance evaluation. Experimental results demonstrate that the proposed algorithm improves the accuracy and computational complexity. PMID:28598358

  16. Spatial Clustering and Local Risk Factors of Chronic Obstructive Pulmonary Disease (COPD).

    PubMed

    Chan, Ta-Chien; Wang, Hsuan-Wen; Tseng, Tzu-Jung; Chiang, Po-Huang

    2015-12-10

    Chronic obstructive pulmonary disease (COPD) mortality has been steadily increasing in Taiwan since 2009. In order to understand where the hotspot areas are and what the local risk factors are, we integrated an ecological and a case-control study. We used a two-stage approach to identify hotspots and explore the possible risk factors for developing COPD. The first stage used the annual township COPD mortality from 2000 to 2012 and applied the retrospective space-time scan statistic to calculate the local relative risks in each township. In the second stage, we conducted a case-control study, recruiting 200 patients from one local hospital within the one identified hotspot area located in southern Taiwan. Logistic regression was applied for analyzing the personal risk factors of COPD. The univariate analyses showed that higher percentages of aborigines, patients with tuberculosis (TB) history, and those with smoking history had COPD (p < 0.05). After controlling for demographic variables, aboriginal status (adjusted odds ratios (AORs): 3.01, 95% CI: 1.52-5.93) and smoking history (AORs: 2.64, 95% CI: 1.46-4.76) were still the two significant risk factors. This two-stage approach might be beneficial to examine and cross-validate the findings from an aggregate to an individual scale, and can be easily extended to other chronic diseases.

  17. Structures, Interconversions, and Spectroscopy of Iron Carbonyl Clusters with an Interstitial Carbide: Localized Metal Center Reduction by Overall Cluster Oxidation.

    PubMed

    Kuppuswamy, Subramaniam; Wofford, Joshua D; Joseph, Chris; Xie, Zhu-Lin; Ali, Azim K; Lynch, Vincent M; Lindahl, Paul A; Rose, Michael J

    2017-05-15

    The syntheses, interconversions, and spectroscopic properties of a set of iron carbonyl clusters containing an interstitial carbide are reported. This includes the low temperature X-ray structures of the six-iron clusters (Y)2[Fe6(μ6-C)(μ2-CO)4(CO)12] (1a-c; where Y = NMe4, NEt4, PPh4); the five-iron cluster [Fe5(μ5-C)(CO)15] (3); and the novel formulation of the five-iron cluster (NMe4)2[Fe5(μ5-C)(μ2-CO)(CO)13] (4). Also included in this set is the novel charge-neutral cluster, [Fe6(μ6-C)(CO)18] (2), for which we were unable to obtain a crystallographic structure. As synthetic proof for the identity of 2, we performed a closed loop of interconversions within a family of crystallographically defined species (1, 3, and 4): [Fe6](2-) → [Fe6](0) → [Fe5](0) → [Fe5](2-) → [Fe6](2-). The structural, spectroscopic, and electronic properties of this "missing link" cluster 2 were investigated by IR, Raman, XPS, and Mössbauer spectroscopies-as well as by DFT calculations. A single νCO feature (1965 cm(-1)) in the IR spectrum of 2, as well as a prominent Raman feature (νsymm = 1550 cm(-1)), are consistent with the presence of terminal carbonyls and a {(μ6-C)Fe6} arrangement of iron centers around the central carbide. The XPS of 2 exhibits a higher energy Fe 2p3/2 feature (707.4 eV) as compared to that of 1 (705.5 eV), consistent with the two-electron oxidation induced by treatment of 1 with two equivalents of [Fc](PF6) under CO atmosphere (for the two added CO ligands). DFT calculations indicate two axial and four equatorial Fe sites in 1, all of which have the same or similar oxidation states, for example, two Fe(0) and four Fe(+0.5). These assignments are supported by Mössbauer spectra for 1, which exhibit two closely spaced quadrupole doublets with δ = 0.076 and 0.064 mm s(-1). The high-field Mössbauer spectrum of 2 (4.2 K) exhibits three prominent quadrupole doublets with δ = -0.18, -0.11, and +0.41 mm s(-1). This indicates three pairs of chemically

  18. Phase Separation in Random Cluster Models I: Uniform Upper Bounds on Local Deviation

    NASA Astrophysics Data System (ADS)

    Hammond, Alan

    2012-03-01

    This is the first in a series of three papers that addresses the behaviour of the droplet that results, in the percolating phase, from conditioning the planar Fortuin-Kasteleyn random cluster model on the presence of an open dual circuit Γ0 encircling the origin and enclosing an area of at least (or exactly) n 2. (By the Fortuin-Kasteleyn representation, the model is a close relative of the droplet formed by conditioning the Potts model on an excess of spins of a given type.) We consider local deviation of the droplet boundary, measured in a radial sense by the maximum local roughness, MLR(Γ0), this being the maximum distance from a point in the circuit Γ0 to the boundary ∂ of the circuit's convex hull; and in a longitudinal sense by what we term maximum facet length, MLF(Γ0), namely, the length of the longest line segment of which the polygon ∂ is formed. The principal conclusion of the series of papers is the following uniform control on local deviation: that there are constants 0 < c < C < ∞ such that the conditional probability that the normalized quantity n -1/3(log n )-2/3MLR lies in the interval [ c, C] tends to 1 in the high n-limit; and that the same statement holds for n -2/3 (log n )-1/3 MLF. In this way, we confirm the anticipated n 1/3 scaling of maximum local roughness, and provide a sharp logarithmic power-law correction. This local deviation behaviour occurs by means of locally Gaussian effects constrained globally by curvature, and we believe that it arises in many radially defined stochastic interface models, including growth models belonging to the Kardar-Parisi-Zhang universality class. The present paper is devoted to proving the upper bounds in these assertions. In fact, we derive bounds valid in the moderate deviations' regime. The second paper (Hammond in Ann Probab, arXiv:1001.1528, 142(2):229-276, 2011) provides the lower bounds. Crucial to our approach are surgical techniques that renew the conditioned circuit on the scale at

  19. Wide-banded NTC radiation: local to remote observations by the four Cluster satellites

    NASA Astrophysics Data System (ADS)

    Décréau, P. M. E.; Aoutou, S.; Denazelle, A.; Galkina, I.; Rauch, J.-L.; Vallières, X.; Canu, P.; Rochel Grimald, S.; El-Lemdani Mazouz, F.; Darrouzet, F.

    2015-10-01

    The Cluster multi-point mission offers a unique collection of non-thermal continuum (NTC) radio waves observed in the 2-80 kHz frequency range over almost 15 years, from various view points over the radiating plasmasphere. Here we present rather infrequent case events, such as when primary electrostatic sources of such waves are embedded within the plasmapause boundary far from the magnetic equatorial plane. The spectral signature of the emitted electromagnetic waves is structured as a series of wide harmonic bands within the range covered by the step in plasma frequency encountered at the boundary. Developing the concept that the frequency distance df between harmonic bands measures the magnetic field magnitude B at the source (df = Fce, electron gyrofrequency), we analyse three selected events. The first one (studied in Grimald et al., 2008) presents electric field signatures observed by a Cluster constellation of small size (~ 200 to 1000 km spacecraft separation) placed in the vicinity of sources. The electric field frequency spectra display frequency peaks placed at frequencies fs = n df (n being an integer), with df of the order of Fce values encountered at the plasmapause by the spacecraft. The second event, taken from the Cluster tilt campaign, leads to a 3-D view of NTC waves ray path orientations and to a localization of a global source region at several Earth radii (RE) from Cluster (Décréau et al., 2013). The measured spectra present successive peaks placed at fs ~ (n+ 1/2) df. Next, considering if both situations might be two facets of the same phenomenon, we analyze a third event. The Cluster fleet, configured into a constellation of large size (~ 8000 to 25 000 km spacecraft separation), allows us to observe wide-banded NTC waves at different distances from their sources. Two new findings can be derived from our analysis. First, we point out that a large portion of the plasmasphere boundary layer, covering a large range of magnetic latitudes, is

  20. Clustering of local group distances: publication bias or correlated measurements? I. The large Magellanic cloud

    SciTech Connect

    De Grijs, Richard; Wicker, James E.; Bono, Giuseppe

    2014-05-01

    The distance to the Large Magellanic Cloud (LMC) represents a key local rung of the extragalactic distance ladder yet the galaxy's distance modulus has long been an issue of contention, in particular in view of claims that most newly determined distance moduli cluster tightly—and with a small spread—around the 'canonical' distance modulus, (m – M){sub 0} = 18.50 mag. We compiled 233 separate LMC distance determinations published between 1990 and 2013. Our analysis of the individual distance moduli, as well as of their two-year means and standard deviations resulting from this largest data set of LMC distance moduli available to date, focuses specifically on Cepheid and RR Lyrae variable-star tracer populations, as well as on distance estimates based on features in the observational Hertzsprung-Russell diagram. We conclude that strong publication bias is unlikely to have been the main driver of the majority of published LMC distance moduli. However, for a given distance tracer, the body of publications leading to the tightly clustered distances is based on highly non-independent tracer samples and analysis methods, hence leading to significant correlations among the LMC distances reported in subsequent articles. Based on a careful, weighted combination, in a statistical sense, of the main stellar population tracers, we recommend that a slightly adjusted canonical distance modulus of (m – M){sub 0} = 18.49 ± 0.09 mag be used for all practical purposes that require a general distance scale without the need for accuracies of better than a few percent.

  1. Clustering of Local Group Distances: Publication Bias or Correlated Measurements? I. The Large Magellanic Cloud

    NASA Astrophysics Data System (ADS)

    de Grijs, Richard; Wicker, James E.; Bono, Giuseppe

    2014-05-01

    The distance to the Large Magellanic Cloud (LMC) represents a key local rung of the extragalactic distance ladder yet the galaxy's distance modulus has long been an issue of contention, in particular in view of claims that most newly determined distance moduli cluster tightly—and with a small spread—around the "canonical" distance modulus, (m - M)0 = 18.50 mag. We compiled 233 separate LMC distance determinations published between 1990 and 2013. Our analysis of the individual distance moduli, as well as of their two-year means and standard deviations resulting from this largest data set of LMC distance moduli available to date, focuses specifically on Cepheid and RR Lyrae variable-star tracer populations, as well as on distance estimates based on features in the observational Hertzsprung-Russell diagram. We conclude that strong publication bias is unlikely to have been the main driver of the majority of published LMC distance moduli. However, for a given distance tracer, the body of publications leading to the tightly clustered distances is based on highly non-independent tracer samples and analysis methods, hence leading to significant correlations among the LMC distances reported in subsequent articles. Based on a careful, weighted combination, in a statistical sense, of the main stellar population tracers, we recommend that a slightly adjusted canonical distance modulus of (m - M)0 = 18.49 ± 0.09 mag be used for all practical purposes that require a general distance scale without the need for accuracies of better than a few percent.

  2. Deconvoluting simulated metagenomes: the performance of hard- and soft- clustering algorithms applied to metagenomic chromosome conformation capture (3C)

    PubMed Central

    DeMaere, Matthew Z.

    2016-01-01

    Background Chromosome conformation capture, coupled with high throughput DNA sequencing in protocols like Hi-C and 3C-seq, has been proposed as a viable means of generating data to resolve the genomes of microorganisms living in naturally occuring environments. Metagenomic Hi-C and 3C-seq datasets have begun to emerge, but the feasibility of resolving genomes when closely related organisms (strain-level diversity) are present in the sample has not yet been systematically characterised. Methods We developed a computational simulation pipeline for metagenomic 3C and Hi-C sequencing to evaluate the accuracy of genomic reconstructions at, above, and below an operationally defined species boundary. We simulated datasets and measured accuracy over a wide range of parameters. Five clustering algorithms were evaluated (2 hard, 3 soft) using an adaptation of the extended B-cubed validation measure. Results When all genomes in a sample are below 95% sequence identity, all of the tested clustering algorithms performed well. When sequence data contains genomes above 95% identity (our operational definition of strain-level diversity), a naive soft-clustering extension of the Louvain method achieves the highest performance. Discussion Previously, only hard-clustering algorithms have been applied to metagenomic 3C and Hi-C data, yet none of these perform well when strain-level diversity exists in a metagenomic sample. Our simple extension of the Louvain method performed the best in these scenarios, however, accuracy remained well below the levels observed for samples without strain-level diversity. Strain resolution is also highly dependent on the amount of available 3C sequence data, suggesting that depth of sequencing must be carefully considered during experimental design. Finally, there appears to be great scope to improve the accuracy of strain resolution through further algorithm development. PMID:27843713

  3. Direct Distance Estimation applied to Eclipsing Binaries in Star Clusters:Case Study of DS Andromedae in NGC 752

    NASA Astrophysics Data System (ADS)

    Milone, Eugene F.; Schiller, Stephen Joseph

    2015-08-01

    Eclipsing binaries (EB) with well-calibrated photometry and precisely measured double-lined radial velocities are candidate standard candles when analyzed with a version of the Wilson-Devinney (WD) light curve modeling program that includes the direct distance estimation (DDE) algorithm. In the DDE procedure, distance is determined as a system parameter, thus avoiding the assumption of stellar sphericity and yielding a well-determined standard error for distance. The method therefore provides a powerful way to calibrate the distances of other objects in any aggregate that contains suitable EB's. DDE has been successfully applied to nearby systems and to a small number of EB's in open clusters. Previously we reported on one of the systems in our Binaries-in-Clusters program, HD27130 = V818 Tau, that had been analyzed with earlier versions of the WD program (see 1987 AJ 93, 1471; 1988 AJ 95, 1466; and 1995 AJ 109, 359 for examples). Results from those early solutions were entered as starting parameters in the current work with the WD 2013 version.Here we report several series of ongoing modeling experiments on a 1.01-d period, early type EB in the intermediate age cluster NGC 752. In one series, ranges of interstellar extinction and hotter star temperature were assumed, and in another series both component temperatures were adjusted. Consistent parameter sets, including distance, confirm DDE's advantages, essentially limited only by knowledge of interstellar extinction, which is small for DS And. Uncertainties in the bandpass calibration constants (flux in standard units from a zero magnitude star) are much less important because derived distance scales (inversely) only with the calibration's square root. This work was enabled by the unstinting help of Bob Wilson. We acknowledge earlier support for the Binaries-in-Clusters program from NSERC of Canada, and the Research Grants Committee and Department of Physics & Astronomy of the University of Calgary.

  4. Upon the opportunity to apply ART2 Neural Network for clusterization of biodiesel fuels

    NASA Astrophysics Data System (ADS)

    Petkov, T.; Mustafa, Z.; Sotirov, S.; Milina, R.; Moskovkina, M.

    2016-03-01

    A chemometric approach using artificial neural network for clusterization of biodiesels was developed. It is based on artificial ART2 neural network. Gas chromatography (GC) and Gas Chromatography - mass spectrometry (GC-MS) were used for quantitative and qualitative analysis of biodiesels, produced from different feedstocks, and FAME (fatty acid methyl esters) profiles were determined. Totally 96 analytical results for 7 different classes of biofuel plants: sunflower, rapeseed, corn, soybean, palm, peanut, "unknown" were used as objects. The analysis of biodiesels showed the content of five major FAME (C16:0, C18:0, C18:1, C18:2, C18:3) and those components were used like inputs in the model. After training with 6 samples, for which the origin was known, ANN was verified and tested with ninety "unknown" samples. The present research demonstrated the successful application of neural network for recognition of biodiesels according to their feedstock which give information upon their properties and handling.

  5. Closed-shell ring coupled cluster doubles theory with range separation applied on weak intermolecular interactions.

    PubMed

    Toulouse, Julien; Zhu, Wuming; Savin, Andreas; Jansen, Georg; Ángyán, János G

    2011-08-28

    We explore different variants of the random phase approximation to the correlation energy derived from closed-shell ring-diagram approximations to coupled cluster doubles theory. We implement these variants in range-separated density-functional theory, i.e., by combining the long-range random phase approximations with short-range density-functional approximations. We perform tests on the rare-gas dimers He(2), Ne(2), and Ar(2), and on the weakly interacting molecular complexes of the S22 set of Jurečka et al. [P. Jurečka, J. Šponer, J. Černý, and P. Hobza, Phys. Chem. Chem. Phys. 8, 1985 (2006)]. The two best variants correspond to the ones originally proposed by Szabo and Ostlund [A. Szabo and N. S. Ostlund, J. Chem. Phys. 67, 4351 (1977)]. With range separation, they reach mean absolute errors on the equilibrium interaction energies of the S22 set of about 0.4 kcal/mol, corresponding to mean absolute percentage errors of about 4%, with the aug-cc-pVDZ basis set.

  6. Ancient coins: cluster analysis applied to find a correlation between corrosion process and burial soil characteristics.

    PubMed

    Reale, Rita; Plattner, Susanne H; Guida, Giuseppe; Sammartino, Maria Pia; Visco, Giovanni

    2012-05-02

    Although it is well known that any material degrades faster when exposed to an aggressive environment as well as that "aggressive" cannot be univocally defined as depending also on the chemical-physical characteristics of material, few researches on the identification of the most significant parameters influencing the corrosion of metallic object are available.A series of ancient coins, coming from the archaeological excavation of Palazzo Valentini (Rome) were collected together with soils, both near and far from them, and then analysed using different analytical techniques looking for a correlation between the corrosion products covering the coins and the chemical-physical soil characteristics. The content of soluble salts in the water-bearing stratum and surfacing in the archaeological site, was also measured.The obtained results stress the influence of alkaline soils on formation of patina. Cerussite, probably due to the circulation of water in layers rich in marble and plaster fragments, was the main corrosion product identified by X-ray Diffraction (XRD). Copper, lead and vanadium were found in soil surrounding coins. By measuring conductivity, pH and soluble salts content of the washing solutions from both coins and soils, we could easily separate coins coming from different stratigraphic units of the site.Data were treated by cluster and multivariate analysis, revealing a correlation between part of the coins and the nearby soil samples.

  7. Ancient coins: cluster analysis applied to find a correlation between corrosion process and burial soil characteristics

    PubMed Central

    2012-01-01

    Although it is well known that any material degrades faster when exposed to an aggressive environment as well as that "aggressive" cannot be univocally defined as depending also on the chemical-physical characteristics of material, few researches on the identification of the most significant parameters influencing the corrosion of metallic object are available. A series of ancient coins, coming from the archaeological excavation of Palazzo Valentini (Rome) were collected together with soils, both near and far from them, and then analysed using different analytical techniques looking for a correlation between the corrosion products covering the coins and the chemical-physical soil characteristics. The content of soluble salts in the water-bearing stratum and surfacing in the archaeological site, was also measured. The obtained results stress the influence of alkaline soils on formation of patina. Cerussite, probably due to the circulation of water in layers rich in marble and plaster fragments, was the main corrosion product identified by X-ray Diffraction (XRD). Copper, lead and vanadium were found in soil surrounding coins. By measuring conductivity, pH and soluble salts content of the washing solutions from both coins and soils, we could easily separate coins coming from different stratigraphic units of the site. Data were treated by cluster and multivariate analysis, revealing a correlation between part of the coins and the nearby soil samples. PMID:22594444

  8. Primary health care in Saudi Arabia: applying global aspects of health for all, locally.

    PubMed

    Littlewood, J; Yousuf, S

    2000-09-01

    Primary health care in Saudi Arabia: applying global aspects of health for all, locally This paper describes the application of primary health care principles in the Islamic Kingdom of Saudi Arabia. It arose from a doctoral supervisory experience on a joint programme for women students, operating between a British and Saudi Arabian University. The research looked at nutritional advice given by diploma-level nurses to pregnant women attending primary health care centres in Saudi Arabia. The supervisor supported research that drew on internationally recognized trends in nursing research (the reflexive learner) whilst attending to local requirements and conventions of the culture. The student was encouraged explicitly to site the research within the framework of Islamic teaching and Saudi culture. The Qur'an was used as an overarching framework within which the tenets of primary health care were explored. This was seen to be crucial in addressing World Health Organisation and the International Council of Nurses' views on contextualizing nursing for the greatest benefit of the population. This was of particular relevance in Saudi Arabia where research carried out in the community by women is novel, and as yet there are no nurse theorists from within Saudi culture.

  9. Locally applied simvastatin improves fracture healing at late period in osteoporotic rat

    NASA Astrophysics Data System (ADS)

    Tian, Faming; Zhang, Liu; Kang, Yuchuan; Zhang, Junshan; Ao, Jiao; Yang, Fang

    effect of simvastatin locally applied from a bioactive polymer coating of implants on osteoporotic fracture healing at late period. Methods:Femur fracture model was established on normal or osteotoporotic mature female SD rats, intramedullary stabilization was achieved with uncoated titanium Kirschnerwires in normal rats(group A),with polymer-only coated vs. polymer plus simvastatin coated titanium Kirschner wires in osteoporotic rats(group B and C, respectively).Femurs were harvested after 12 weeks, and underwent radiographic and histologic analysis, as well as immunohistochemical evaluation for BMP-2 expression. Results:Radiographic results demonstrated progressed callus in the simvastatin-treated groups compared to the uncoated group.The histologic analysis revealed a significantly processed callus with irregular-shaped newly formed bone trabeculae in simvastatin-treated group. Immunohistochemical evaluation showed markedly higher expression levels of B:MP-2 in simvastatin-treated group.Conclusions: The present study revealed a improved fracture healing under local application of simvastatin in osteoporotic rat,which might partially from upregulation of the B:MP-2 expression at fractured site.

  10. Recent Developments of the Local Effect Model (LEM) - Implications of clustered damage on cell transformation

    NASA Astrophysics Data System (ADS)

    Elsässer, Thilo

    Exposure to radiation of high-energy and highly charged ions (HZE) causes a major risk to human beings, since in long term space explorations about 10 protons per month and about one HZE particle per month hit each cell nucleus (1). Despite the larger number of light ions, the high ionisation power of HZE particles and its corresponding more complex damage represents a major hazard for astronauts. Therefore, in order to get a reasonable risk estimate, it is necessary to take into account the entire mixed radiation field. Frequently, neoplastic cell transformation serves as an indicator for the oncogenic potential of radiation exposure. It can be measured for a small number of ion and energy combinations. However, due to the complexity of the radiation field it is necessary to know the contribution to the radiation damage of each ion species for the entire range of energies. Therefore, a model is required which transfers the few experimental data to other particles with different LETs. We use the Local Effect Model (LEM) (2) with its cluster extension (3) to calculate the relative biological effectiveness (RBE) of neoplastic transformation. It was originally developed in the framework of hadrontherapy and is applicable for a large range of ions and energies. The input parameters for the model include the linear-quadratic parameters for the induction of lethal events as well as for the induction of transformation events per surviving cell. Both processes of cell inactivation and neoplastic transformation per viable cell are combined to eventually yield the RBE for cell transformation. We show that the Local Effect Model is capable of predicting the RBE of neoplastic cell transformation for a broad range of ions and energies. The comparison of experimental data (4) with model calculations shows a reasonable agreement. We find that the cluster extension results in a better representation of the measured RBE values. With this model it should be possible to better

  11. Comparing the properties of local globular cluster systems: implications for the formation of the Galactic halo

    NASA Astrophysics Data System (ADS)

    Mackey, A. D.; Gilmore, G. F.

    2004-12-01

    We investigate the hypothesis that some fraction of the globular clusters presently observed in the Galactic halo formed in external dwarf galaxies. This is done by means of a detailed comparison between the `old halo', `young halo' and `bulge/disc' subsystems defined by Zinn and the globular clusters in the Large Magellanic Cloud, Small Magellanic Cloud, and Fornax and Sagittarius dwarf spheroidal galaxies. We first use high-quality photometry from Hubble Space Telescope images to derive a complete set of uniform measurements of horizontal branch (HB) morphology in the external clusters. We also compile structural and metallicity measurements for these objects and update the data base of such measurements for the Galactic globular clusters, including new calculations of HB morphology for 11 objects. Using these data together with recent measurements of globular cluster kinematics and ages we examine the characteristics of the three Galactic cluster subsystems. Each is quite distinct in terms of their spatial and age distributions, age-metallicity relationships, and typical orbital parameters, although we observe some old halo clusters with ages and orbits more similar to those of young halo objects. In addition, almost all of the Galactic globular clusters with large core radii fall into the young halo subsystem, while the old halo and bulge/disc ensembles are characterized by compact clusters. We demonstrate that the majority of the external globular clusters are essentially indistinguishable from the Galactic young halo objects in terms of HB morphology, but ~20-30 per cent of external clusters have HB morphologies most similar to the Galactic old halo clusters. We further show that the external clusters have a distribution of core radii which very closely matches that for the young halo objects. The old halo distribution of core radii can be very well represented by a composite distribution formed from ~83-85 per cent of objects with structures typical of bulge

  12. Highly charged ions from laser-cluster interactions: local-field-enhanced impact ionization and frustrated electron-ion recombination.

    PubMed

    Fennel, Thomas; Ramunno, Lora; Brabec, Thomas

    2007-12-07

    Our molecular dynamics analysis of Xe_{147-5083} clusters identifies two mechanisms that contribute to the yet unexplained observation of extremely highly charged ions in intense laser cluster experiments. First, electron impact ionization is enhanced by the local cluster electric field, increasing the highest charge states by up to 40%; a corresponding theoretical method is developed. Second, electron-ion recombination after the laser pulse is frustrated by acceleration electric fields typically used in ion detectors. This increases the highest charge states by up to 90%, as compared to the usual assumption of total recombination of all cluster-bound electrons. Both effects together augment the highest charge states by up to 120%, in reasonable agreement with experiments.

  13. Highly Charged Ions from Laser-Cluster Interactions: Local-Field-Enhanced Impact Ionization and Frustrated Electron-Ion Recombination

    SciTech Connect

    Fennel, Thomas; Ramunno, Lora; Brabec, Thomas

    2007-12-07

    Our molecular dynamics analysis of Xe{sub 147-5083} clusters identifies two mechanisms that contribute to the yet unexplained observation of extremely highly charged ions in intense laser cluster experiments. First, electron impact ionization is enhanced by the local cluster electric field, increasing the highest charge states by up to 40%; a corresponding theoretical method is developed. Second, electron-ion recombination after the laser pulse is frustrated by acceleration electric fields typically used in ion detectors. This increases the highest charge states by up to 90%, as compared to the usual assumption of total recombination of all cluster-bound electrons. Both effects together augment the highest charge states by up to 120%, in reasonable agreement with experiments.

  14. ClubSub-P: Cluster-Based Subcellular Localization Prediction for Gram-Negative Bacteria and Archaea

    PubMed Central

    Paramasivam, Nagarajan; Linke, Dirk

    2011-01-01

    The subcellular localization (SCL) of proteins provides important clues to their function in a cell. In our efforts to predict useful vaccine targets against Gram-negative bacteria, we noticed that misannotated start codons frequently lead to wrongly assigned SCLs. This and other problems in SCL prediction, such as the relatively high false-positive and false-negative rates of some tools, can be avoided by applying multiple prediction tools to groups of homologous proteins. Here we present ClubSub-P, an online database that combines existing SCL prediction tools into a consensus pipeline from more than 600 proteomes of fully sequenced microorganisms. On top of the consensus prediction at the level of single sequences, the tool uses clusters of homologous proteins from Gram-negative bacteria and from Archaea to eliminate false-positive and false-negative predictions. ClubSub-P can assign the SCL of proteins from Gram-negative bacteria and Archaea with high precision. The database is searchable, and can easily be expanded using either new bacterial genomes or new prediction tools as they become available. This will further improve the performance of the SCL prediction, as well as the detection of misannotated start codons and other annotation errors. ClubSub-P is available online at http://toolkit.tuebingen.mpg.de/clubsubp/ PMID:22073040

  15. Dynamical Cluster-decay Model (DCM) applied to 9Li+208Pb reaction

    NASA Astrophysics Data System (ADS)

    Kaur, Arshdeep; Hemdeep; Kaushal, Pooja; Behera, Bivash R.; Gupta, Raj K.

    2017-10-01

    The decay mechanism of 217At* formed in 9Li+208Pb reaction is studied within the dynamical cluster-decay model (DCM) at various center-of-mass energies. The aim is to see the behavior of a light neutron-rich radioactive beam on a doubly-magic target nucleus for the (total) fusion cross section σfus and the individual decay channel cross sections. Experimentally, only the isotopic yield of heavy mass residues 211-214At * [equivalently, the light-particles (LPs) evaporation residue cross sections σxn for x = 3- 6 neutrons emission] are measured, with the fusion-fission (ff) component σff taken zero. For a fixed neck-length parameter ΔR, the only parameter in the DCM, we are able to fit σfus =∑x=16σxn almost exactly for 9Li on 208Pb at all E c . m .'s. However, the observed individual decay channels (3n-6n) are very poorly fitted, with unobserved channels (1n, 2n) and σff strongly over-estimated. Different ΔR values, meaning thereby different reaction time scales, are required to fit individually both the observed and unobserved evaporation residue channels (1n-6n) and σff, but then the compound nucleus (CN) contribution σCN is very small (< 1%), and the non-compound nucleus (nCN) decay cross section σnCN contributes the most towards total σfus (=σCN +σnCN). Thus, the 9Li induced reaction on doubly-magic 208Pb is more of a quasi-fission-like nCN decay, which is further analyzed in terms of the statistical CN formation probability PCN and CN survival probability Psurv. For the reaction under study, PCN < < 1 and Psurv → 1, in particular at above barrier energies.

  16. Inverse Estimation of SO2 Emissions over China with Local Air Mass Factor Applied

    NASA Astrophysics Data System (ADS)

    Wang, Y.; Wang, J.; Xu, X.; Henze, D. K.

    2015-12-01

    Sulfur dioxide (SO2) has significant impacts on human health as it forms sulfate aerosols in the atmosphere. Widespread uncertainty in the magnitude of SO2 emissions hinders efforts to address this issue. In this work we use Ozone Monitoring Instrument (OMI) slant column SO2 observations as constraints to conduct inversion of SO2 emissions over China for April 2008. Local air mass factors are formulated as the integral of the relative vertical distribution of SO2 simulated from GEOS-Chem, weighted by scattering weights computed from VLIDORT. They are applied to convert slant column to vertical column GEOS-Chem SO2. After data assimilation SO2 emissions decrease in Sichuan Basin, South China, and most areas of North China. The posterior SO2 emissions are evaluated with in situ SO2 observation. Besides, we apply the posterior SO2 emissions of April 2008 to April 2009, and it leads to improved agreement of modeled SO2 to the OMI observations. This offers potential to update SO2 emissions in real time.

  17. Molecular dipole static polarisabilities and hyperpolarisabilities of conjugated oligomer chains calculated with the local π-electron coupled cluster theory

    NASA Astrophysics Data System (ADS)

    Ivanov, Vladimir V.; Zakharov, Anton B.; Adamowicz, Ludwik

    2013-12-01

    A new semi-empirical π-electron local coupled cluster theory has been developed to calculate static dipole polarisabilities and hyperpolarisabilities of extended π-conjugated systems. The key idea of the approach is the use of the ethylene molecular orbitals as the orbital basis set for π-conjugated compounds (the method is termed the Covalent Unbonded Molecules of Ethylene method, cue). Test calculations of some small model organic conjugated compounds demonstrate high accuracy of the version of the cue local coupled cluster theory developed in this work in comparison with the π-electron full configuration interaction (FCI) method. Calculations of different conjugated carbon-based oligomer chains (polyenes, polyynes, polyacenes, polybenzocyclobutadiene, etc.) demonstrate fast convergence (per π-electron) of the polarisability and hyperpolarisability values in the calculations when more classes of orbital excitations are included in the coupled cluster single and double (CCSD) excitation operator. The results show qualitatively correct dependence on the system size.

  18. An efficient and near linear scaling pair natural orbital based local coupled cluster method

    NASA Astrophysics Data System (ADS)

    Riplinger, Christoph; Neese, Frank

    2013-01-01

    In previous publications, it was shown that an efficient local coupled cluster method with single- and double excitations can be based on the concept of pair natural orbitals (PNOs) [F. Neese, A. Hansen, and D. G. Liakos, J. Chem. Phys. 131, 064103 (2009), 10.1063/1.3173827]. The resulting local pair natural orbital-coupled-cluster single double (LPNO-CCSD) method has since been proven to be highly reliable and efficient. For large molecules, the number of amplitudes to be determined is reduced by a factor of 105-106 relative to a canonical CCSD calculation on the same system with the same basis set. In the original method, the PNOs were expanded in the set of canonical virtual orbitals and single excitations were not truncated. This led to a number of fifth order scaling steps that eventually rendered the method computationally expensive for large molecules (e.g., >100 atoms). In the present work, these limitations are overcome by a complete redesign of the LPNO-CCSD method. The new method is based on the combination of the concepts of PNOs and projected atomic orbitals (PAOs). Thus, each PNO is expanded in a set of PAOs that in turn belong to a given electron pair specific domain. In this way, it is possible to fully exploit locality while maintaining the extremely high compactness of the original LPNO-CCSD wavefunction. No terms are dropped from the CCSD equations and domains are chosen conservatively. The correlation energy loss due to the domains remains below <0.05%, which implies typically 15-20 but occasionally up to 30 atoms per domain on average. The new method has been given the acronym DLPNO-CCSD ("domain based LPNO-CCSD"). The method is nearly linear scaling with respect to system size. The original LPNO-CCSD method had three adjustable truncation thresholds that were chosen conservatively and do not need to be changed for actual applications. In the present treatment, no additional truncation parameters have been introduced. Any additional truncation

  19. Local traps as nanoscale reaction-diffusion probes: B clustering in c-Si

    NASA Astrophysics Data System (ADS)

    Pawlak, B. J.; Cowern, N. E. B.; Ahn, C.; Vandervorst, W.; Gwilliam, R.; van Berkum, J. G. M.

    2014-12-01

    A series of B implantation experiments into initially amorphized and not fully recrystallized Si, i.e., into an existing a/c-Si bi-layer material, have been conducted. We varied B dose, energy, and temperature during implantation process itself. Significant B migration has been observed within c-Si part near the a/c-interface and near the end-of-range region before any activation annealing. We propose a general concept of local trapping sites as experimental probes of nanoscale reaction-diffusion processes. Here, the a/c-Si interface acts as a trap, and the process itself is explored as the migration and clustering of mobile BI point defects in nearby c-Si during implantation at temperatures from 77 to 573 K. We find that at room temperature—even at B concentrations as high as 1.6 atomic %, the key B-B pairing step requires diffusion lengths of several nm owing to a small, ˜0.1 eV, pairing energy barrier. Thus, in nanostructures doped by ion implantation, the implant distribution can be strongly influenced by thermal migration to nearby impurities, defects, and interfaces.

  20. Natural triple excitations in local coupled cluster calculations with pair natural orbitals

    NASA Astrophysics Data System (ADS)

    Riplinger, Christoph; Sandhoefer, Barbara; Hansen, Andreas; Neese, Frank

    2013-10-01

    In this work, the extension of the previously developed domain based local pair-natural orbital (DLPNO) based singles- and doubles coupled cluster (DLPNO-CCSD) method to perturbatively include connected triple excitations is reported. The development is based on the concept of triples-natural orbitals that span the joint space of the three pair natural orbital (PNO) spaces of the three electron pairs that are involved in the calculation of a given triple-excitation contribution. The truncation error is very smooth and can be significantly reduced through extrapolation to the zero threshold. However, the extrapolation procedure does not improve relative energies. The overall computational effort of the method is asymptotically linear with the system size O(N). Actual linear scaling has been confirmed in test calculations on alkane chains. The accuracy of the DLPNO-CCSD(T) approximation relative to semicanonical CCSD(T0) is comparable to the previously developed DLPNO-CCSD method relative to canonical CCSD. Relative energies are predicted with an average error of approximately 0.5 kcal/mol for a challenging test set of medium sized organic molecules. The triples correction typically adds 30%-50% to the overall computation time. Thus, very large systems can be treated on the basis of the current implementation. In addition to the linear C150H302 (452 atoms, >8800 basis functions) we demonstrate the first CCSD(T) level calculation on an entire protein, Crambin with 644 atoms, and more than 6400 basis functions.

  1. Local traps as nanoscale reaction-diffusion probes: B clustering in c-Si

    SciTech Connect

    Pawlak, B. J.; Cowern, N. E. B.; Ahn, C.; Vandervorst, W.; Gwilliam, R.; Berkum, J. G. M. van

    2014-12-01

    A series of B implantation experiments into initially amorphized and not fully recrystallized Si, i.e., into an existing a/c-Si bi-layer material, have been conducted. We varied B dose, energy, and temperature during implantation process itself. Significant B migration has been observed within c-Si part near the a/c-interface and near the end-of-range region before any activation annealing. We propose a general concept of local trapping sites as experimental probes of nanoscale reaction-diffusion processes. Here, the a/c-Si interface acts as a trap, and the process itself is explored as the migration and clustering of mobile BI point defects in nearby c-Si during implantation at temperatures from 77 to 573 K. We find that at room temperature—even at B concentrations as high as 1.6 atomic %, the key B-B pairing step requires diffusion lengths of several nm owing to a small, ∼0.1 eV, pairing energy barrier. Thus, in nanostructures doped by ion implantation, the implant distribution can be strongly influenced by thermal migration to nearby impurities, defects, and interfaces.

  2. Periodotopy in the gerbil inferior colliculus: local clustering rather than a gradient map

    PubMed Central

    Schnupp, Jan W. H.; Garcia-Lazaro, Jose A.; Lesica, Nicholas A.

    2015-01-01

    Periodicities in sound waveforms are widespread, and shape important perceptual attributes of sound including rhythm and pitch. Previous studies have indicated that, in the inferior colliculus (IC), a key processing stage in the auditory midbrain, neurons tuned to different periodicities might be arranged along a periodotopic axis which runs approximately orthogonal to the tonotopic axis. Here we map out the topography of frequency and periodicity tuning in the IC of gerbils in unprecedented detail, using pure tones and different periodic sounds, including click trains, sinusoidally amplitude modulated (SAM) noise and iterated rippled noise. We found that while the tonotopic map exhibited a clear and highly reproducible gradient across all animals, periodotopic maps varied greatly across different types of periodic sound and from animal to animal. Furthermore, periodotopic gradients typically explained only about 10% of the variance in modulation tuning between recording sites. However, there was a strong local clustering of periodicity tuning at a spatial scale of ca. 0.5 mm, which also differed from animal to animal. PMID:26379508

  3. Localization of interchromatin granule cluster and Cajal body components in oocyte nuclear bodies of the hemipterans.

    PubMed

    Bogolyubov, D S; Batalova, F M; Ogorzałek, A

    2007-10-01

    An oocyte nucleus contains different extrachromosomal nuclear domains collectively called nuclear bodies (NBs). In the present work we revealed, using immunogold labeling electron microscopy, some marker components of interchromatin granule clusters (IGCs) and Cajal bodies (CBs) in morphologically heterogeneous oocyte NBs studied in three hemipteran species: Notostira elongata, Capsodes gothicus (Miridae) and Velia caprai (Veliidae). Both IGC and CB counterparts were revealed in oocyte nuclei of the studied species but morphological and biochemical criteria were found to be not sufficient to determine carefully the define type of oocyte NBs. We found that the molecular markers of the CBs (coilin and non-phosphorylated RNA polymerase II) and IGCs (SC35 protein) may be localized in the same NB. Anti-SC35 antibody may decorate not only a granular material representing "true" interchromatin granules but also masks some fibrillar parts of complex NBs. Our first observations on the hemipteran oocyte NBs confirm the high complexity and heterogeneity of insect oocyte IGCs and CBs in comparison with those in mammalian somatic cells and amphibian oocytes.

  4. Dissecting the Biochemical and Transcriptomic Effects of a Locally Applied Heat Treatment on Developing Cabernet Sauvignon Grape Berries

    PubMed Central

    Lecourieux, Fatma; Kappel, Christian; Pieri, Philippe; Charon, Justine; Pillet, Jérémy; Hilbert, Ghislaine; Renaud, Christel; Gomès, Eric; Delrot, Serge; Lecourieux, David

    2017-01-01

    Reproductive development of grapevine and berry composition are both strongly influenced by temperature. To date, the molecular mechanisms involved in grapevine berries response to high temperatures are poorly understood. Unlike recent data that addressed the effects on berry development of elevated temperatures applied at the whole plant level, the present work particularly focuses on the fruit responses triggered by direct exposure to heat treatment (HT). In the context of climate change, this work focusing on temperature effect at the microclimate level is of particular interest as it can help to better understand the consequences of leaf removal (a common viticultural practice) on berry development. HT (+ 8°C) was locally applied to clusters from Cabernet Sauvignon fruiting cuttings at three different developmental stages (middle green, veraison and middle ripening). Samples were collected 1, 7, and 14 days after treatment and used for metabolic and transcriptomic analyses. The results showed dramatic and specific biochemical and transcriptomic changes in heat exposed berries, depending on the developmental stage and the stress duration. When applied at the herbaceous stage, HT delayed the onset of veraison. Heating also strongly altered the berry concentration of amino acids and organic acids (e.g., phenylalanine, γ-aminobutyric acid and malate) and decreased the anthocyanin content at maturity. These physiological alterations could be partly explained by the deep remodeling of transcriptome in heated berries. More than 7000 genes were deregulated in at least one of the nine experimental conditions. The most affected processes belong to the categories “stress responses,” “protein metabolism” and “secondary metabolism,” highlighting the intrinsic capacity of grape berries to perceive HT and to build adaptive responses. Additionally, important changes in processes related to “transport,” “hormone” and “cell wall” might contribute to the

  5. High and low neurobehavior disinhibition clusters within locales: implications for community efforts to prevent substance use disorder.

    PubMed

    Ridenour, Ty A; Reynolds, Maureen; Ahlqvist, Ola; Zhai, Zu Wei; Kirisci, Levent; Vanyukov, Michael M; Tarter, Ralph E

    2013-05-01

    Knowledge of where substance use and other such behavioral problems frequently occur has aided policing, public health, and urban planning strategies to reduce such behaviors. Identifying locales characterized by high childhood neurobehavioral disinhibition (ND), a strong predictor of substance use and consequent disorder (SUD), may likewise improve prevention efforts. The distribution of ND in 10-12-year olds was mapped to metropolitan Pittsburgh, PA, and tested for clustering within locales. The 738 participating families represented the population in terms of economic status, race, and population distribution. ND was measured using indicators of executive cognitive function, emotion regulation, and behavior control. Innovative geospatial analyzes statistically tested clustering of ND within locales while accounting for geographic barriers (large rivers, major highways), parental SUD severity, and neighborhood quality. Clustering of youth with high and low ND occurred in specific locales. Accounting for geographic barriers better delineated where high ND is concentrated, areas which also tended to be characterized by greater parental SUD severity and poorer neighborhood quality. Offering programs that have been demonstrated to improve inhibitory control in locales where youth have high ND on average may reduce youth risk for SUD and other problem behaviors. As demonstrated by the present results, geospatial analysis of youth risk factors, frequently used in community coalition strategies, may be improved with greater statistical and measurement rigor.

  6. High and Low Neurobehavior Disinhibition Clusters within Locales: Implications for Community Efforts to Prevent Substance Use Disorder

    PubMed Central

    Ridenour, Ty A.; Reynolds, Maureen; Ahlqvist, Ola; Zhai, Zu Wei; Kirisci, Levent; Vanyukov, Michael M.; Tarter, Ralph E.

    2014-01-01

    Background Knowledge of where substance use and other such behavioral problems frequently occur has aided policing, public health, and urban planning strategies to reduce such behaviors. Identifying locales characterized by high childhood neurobehavioral disinhibition (ND), a strong predictor of substance use and consequent disorder (SUD), may likewise improve prevention efforts. Objectives The distribution of ND in 10–12-year olds was mapped to metropolitan Pittsburgh, PA, and tested for clustering within locales. Methods The 738 participating families represented the population in terms of economic status, race, and population distribution. ND was measured using indicators of executive cognitive function, emotion regulation, and behavior control. Innovative geospatial analyzes statistically tested clustering of ND within locales while accounting for geographic barriers (large rivers, major highways), parental SUD severity, and neighborhood quality. Results Clustering of youth with high and low ND occurred in specific locales. Accounting for geographic barriers better delineated where high ND is concentrated, areas which also tended to be characterized by greater parental SUD severity and poorer neighborhood quality. Conclusions and Significance Offering programs that have been demonstrated to improve inhibitory control in locales where youth have high ND on average may reduce youth risk for SUD and other problem behaviors. As demonstrated by the present results, geospatial analysis of youth risk factors, frequently used in community coalition strategies, may be improved with greater statistical and measurement rigor. PMID:23721535

  7. Theoretical study on local defect structure of (FeO4)5- clusters in YGG and LGG crystals

    NASA Astrophysics Data System (ADS)

    Li, Hui-Li; Kuang, Xiao-Yu; Li, Ying; Mao, Ai-Jie

    2009-07-01

    The optical spectrum and the local defect structure of tetrahedral (FeO4)5- clusters are investigated in yttrium gallium garnet (YGG) and lutetium gallium garnet (LGG) crystals by means of the 252 × 252 complete energy matrices for d5 configuration ions in tetragonal ligand field. The results show that the local defect structures around tetrahedral Fe3+ centers display an expansion effect. Simultaneously, the (FeO4)5- clusters in the two different crystals have very similar local structures, which are close to those in YIG garnet crystal. Finally the relative curves of the zero-field splitting energies ΔE1 and ΔE2 in the ground state 6A1 varying with the structure parameter θ are plotted.

  8. Theoretical study on local defect structure of (FeO4)(5-) clusters in YGG and LGG crystals.

    PubMed

    Li, Hui-Li; Kuang, Xiao-Yu; Li, Ying; Mao, Ai-Jie

    2009-07-15

    The optical spectrum and the local defect structure of tetrahedral (FeO4)(5-) clusters are investigated in yttrium gallium garnet (YGG) and lutetium gallium garnet (LGG) crystals by means of the 252x252 complete energy matrices for d(5) configuration ions in tetragonal ligand field. The results show that the local defect structures around tetrahedral Fe3+ centers display an expansion effect. Simultaneously, the (FeO4(5-) clusters in the two different crystals have very similar local structures, which are close to those in YIG garnet crystal. Finally the relative curves of the zero-field splitting energies DeltaE1 and DeltaE2 in the ground state (6)A(1) varying with the structure parameter theta are plotted.

  9. Clustering and interpretation of local earthquake tomography models in the southern Dead Sea basin

    NASA Astrophysics Data System (ADS)

    Bauer, Klaus; Braeuer, Benjamin

    2016-04-01

    The Dead Sea transform (DST) marks the boundary between the Arabian and the African plates. Ongoing left-lateral relative plate motion and strike-slip deformation started in the Early Miocene (20 MA) and produced a total shift of 107 km until presence. The Dead Sea basin (DSB) located in the central part of the DST is one of the largest pull-apart basins in the world. It was formed from step-over of different fault strands at a major segment boundary of the transform fault system. The basin development was accompanied by deposition of clastics and evaporites and subsequent salt diapirism. Ongoing deformation within the basin and activity of the boundary faults are indicated by increased seismicity. The internal architecture of the DSB and the crustal structure around the DST were subject of several large scientific projects carried out since 2000. Here we report on a local earthquake tomography study from the southern DSB. In 2006-2008, a dense seismic network consisting of 65 stations was operated for 18 months in the southern part of the DSB and surrounding regions. Altogether 530 well-constrained seismic events with 13,970 P- and 12,760 S-wave arrival times were used for a travel time inversion for Vp, Vp/Vs velocity structure and seismicity distribution. The work flow included 1D inversion, 2.5D and 3D tomography, and resolution analysis. We demonstrate a possible strategy how several tomographic models such as Vp, Vs and Vp/Vs can be integrated for a combined lithological interpretation. We analyzed the tomographic models derived by 2.5D inversion using neural network clustering techniques. The method allows us to identify major lithologies by their petrophysical signatures. Remapping the clusters into the subsurface reveals the distribution of basin sediments, prebasin sedimentary rocks, and crystalline basement. The DSB shows an asymmetric structure with thickness variation from 5 km in the west to 13 km in the east. Most importantly, a well-defined body

  10. Approaching the bulk limit with finite cluster calculations using local increments: the case of LiH.

    PubMed

    Stoll, Hermann; Doll, Klaus

    2012-02-21

    Finite-cluster calculations employing high-level wavefunction-based ab initio methods and extended atomic-orbital basis sets are used to determine local energy increments for bulk LiH. It is shown that these increments can be converged with respect to cluster size and point-charge embedding so as to yield bulk cohesive energies with an accuracy of better than 1 mE(h), both at the Hartree-Fock and at correlated levels. Instrumental for the efficiency of the scheme is the introduction of non-orthogonal orbitals, at an intermediate stage.

  11. A Parallel EM Algorithm for Model-Based Clustering Applied to the Exploration of Large Spatio-Temporal Data

    SciTech Connect

    Chen, Wei-Chen; Ostrouchov, George; Pugmire, Dave; Prabhat,; Wehner, Michael

    2013-01-01

    We develop a parallel EM algorithm for multivariate Gaussian mixture models and use it to perform model-based clustering of a large climate data set. Three variants of the EM algorithm are reformulated in parallel and a new variant that is faster is presented. All are implemented using the single program, multiple data (SPMD) programming model, which is able to take advantage of the combined collective memory of large distributed computer architectures to process larger data sets. Displays of the estimated mixture model rather than the data allow us to explore multivariate relationships in a way that scales to arbitrary size data. We study the performance of our methodology on simulated data and apply our methodology to a high resolution climate dataset produced by the community atmosphere model (CAM5). This article has supplementary material online.

  12. Tissue heterogeneity as a mechanism for localized neural stimulation by applied electric fields

    NASA Astrophysics Data System (ADS)

    Miranda, P. C.; Correia, L.; Salvador, R.; Basser, P. J.

    2007-09-01

    We investigate the heterogeneity of electrical conductivity as a new mechanism to stimulate excitable tissues via applied electric fields. In particular, we show that stimulation of axons crossing internal boundaries can occur at boundaries where the electric conductivity of the volume conductor changes abruptly. The effectiveness of this and other stimulation mechanisms was compared by means of models and computer simulations in the context of transcranial magnetic stimulation. While, for a given stimulation intensity, the largest membrane depolarization occurred where an axon terminates or bends sharply in a high electric field region, a slightly smaller membrane depolarization, still sufficient to generate action potentials, also occurred at an internal boundary where the conductivity jumped from 0.143 S m-1 to 0.333 S m-1, simulating a white-matter-grey-matter interface. Tissue heterogeneity can also give rise to local electric field gradients that are considerably stronger and more focal than those impressed by the stimulation coil and that can affect the membrane potential, albeit to a lesser extent than the two mechanisms mentioned above. Tissue heterogeneity may play an important role in electric and magnetic 'far-field' stimulation.

  13. Quantitative aspects of digital microscopy applied to cellular localization of heparin in smooth muscle cells

    NASA Astrophysics Data System (ADS)

    Johnston, Richard F.; Hanzel, David K.; Stack, Bob; Brandley, Brian; Castellot, John

    1995-04-01

    High Resolution digital acquisition allows a great deal of flexibility in the types of questions that can be directed to microscopic samples. To eliminate subjective bias and provide quantitative results we have approached microscopy with an automated digital format. This mode can return quantitative data at high resolution over large fields. The digital format makes accessible data including [data segmentation]: multispectral colocalization, seeding and connectivity, particle size and shape distribution and population analysis. We have begun a program to investigate this approach using the confocal microscope. Scanning larger fields-of-view at lower spatial resolutions (e.g., low magnification objective) defines large maps that allow alignment of high spatial resolution (diffraction limited) sampling. The [objective] selection of the field-of-view with low spatial resolution reduces the subjective nature of the selection of a 'typical staining pattern'. High resolution digital scanning in three dimensions contribute both to the 'objective' nature of the analysis and allow for quantitation of characteristics not historically available/accessible. The complex carbohydrate heparin is implicated in tumor growth and wound healing by affecting angiogenesis, cell proliferation and motility. The internal localization of heparin within vascular cells appears to be a good predictor of the sensitivity of those cells to the action of heparin. Cells resistant to the antiproliferative action of heparin are able to sequester the heparin in large vacuoles whereas those cells sensitive to the carbohydrate do not exhibit these structures. We have applied our approach to QUANTITATIVE DIGITAL MICROSCOPY to the analysis of intracellular heparin distribution.

  14. Local protrusions formed on Si(111) surface by surface melting and solidification under applied tensile stress

    NASA Astrophysics Data System (ADS)

    Nishimura, T.; Tomitori, M.

    2016-09-01

    The surface structure and composition of Si(111) was modified, by heating it to 1300 °C in ultrahigh vacuum under an external tensile stress. A stress of approximately 1 GPa was applied, by pressing on the center of the rear side of the sample. This process produced two protrusions of approximately 100 μm in height, to the left and right of the center. Scanning Auger electron spectroscopy revealed Fe, Cr, Ni, and C impurities at the top of one protrusion, and C at the top of the other. These impurities likely diffused into the tops of the protrusions during heating, and segregated to the local surface during cooling when the protrusions formed. The protrusion formation mechanism is discussed. Their formation was related to non-uniform surface temperature, electromigration, piezoresistivity, freezing-point depression due to surface alloying with the impurities, and volume expansion during solidification from surface melting. These findings provide a perspective on controlling surface structures and compositions using heat and stress to induce self-assembly.

  15. Skin blood flow response to locally applied mechanical and thermal stresses in the diabetic foot.

    PubMed

    Jan, Yih-Kuen; Shen, Sa; Foreman, Robert D; Ennis, William J

    2013-09-01

    Diabetic foot ulcers are one of the most common complications in diabetics, causing significant disabilities and decreasing the quality of life. Impaired microvascular reactivity contributes to the development of diabetic foot ulcers. However, underlying physiological mechanisms responsible for the impaired microvascular reactivity in response to extrinsic causative factors of foot ulcers such as mechanical and thermal stresses have not been well investigated. A total of 26 participants were recruited into this study, including 18 type 2 diabetics with peripheral neuropathy and 8 healthy controls. Laser Doppler flowmetry was used to measure skin blood flow at the first metatarsal head in response to a mechanical stress at 300mmHg and a fast thermal stress at 42°C. Wavelet analysis of skin blood flow oscillations was used to assess metabolic, neurogenic and myogenic controls. Our results indicated that diabetics have significantly decreased metabolic, neurogenic and myogenic responses to thermal stress, especially in the neurogenic and myogenic controls during the first vasodilatory response and in the metabolic control during the second vasodilatory response. Diabetics have a significantly decreased myogenic response to mechanical stress during reactive hyperemia. Our findings demonstrate that locally applied mechanical and thermal stresses can be used to assess microvascular reactivity and risk of diabetic foot ulcers.

  16. Externally applied cyclic strain regulates localization of focal contact components in cultured smooth muscle cells.

    PubMed

    Cunningham, James J; Linderman, Jennifer J; Mooney, David J

    2002-01-01

    Mechanical signals are critical regulators of cellular gene expression, yet little is understood of the mechanism whereby cells sense mechanical forces. In this study we have tested the hypothesis that mechanical strain applied to populations of cells via their adhesion substrate rapidly alters the cellular distribution of focal contact proteins. Focal contact-associated components (vinculin, a-actinin, paxillin) were assayed by immunofluorescence microscopy and quantitative western blotting. Application of a single step increase in strain in multiple experiments caused overall a small change in focal contact-associated vinculin. In contrast, cyclic strain induced a large and very reproducible increase in detergent-insoluble vinculin (52% relative to static) after just 1 min of strain. Insoluble paxillin was transiently enriched with a similar time course, whereas insoluble a-actinin did not change significantly in response to cyclic strain. Rhodamine-labeled chicken vinculin added to permeabilized cells preferentially localized to focal contacts in response to cyclic strain, but not a single step increase in strain. These findings establish that insoluble levels of focal contact components are altered rapidly following application of an appropriate number of mechanical perturbations, and suggest that at least one component of the mechanism does not involve soluble intermediates.

  17. A ``local observables'' method for wave mechanics applied to atomic hydrogen

    NASA Astrophysics Data System (ADS)

    Bowman, Peter J.

    2008-12-01

    An alternative method of deriving the values of the observables of atomic systems is presented. Rather than using operators and eigenvalues the local variables method uses the continuity equation together with current densities derived from wave functions that are solutions of the Dirac or Pauli equation. The method is applied to atomic hydrogen using the usual language of quantum mechanics rather than that of geometric algebra with which the method is often associated. The picture of the atom that emerges is one in which the electron density as a whole is rotating about a central axis. The results challenge some assumptions of conventional quantum mechanics. Electron spin is shown to be a property of the dynamical motion of the electron and not an intrinsic property of the electron, the ground state of hydrogen is shown to have an orbital angular momentum of ℏ, and excited states are shown to have angular momenta that are different from the eigenvalues of the usual quantum mechanical operators. The uncertainty relations are found not to be applicable to the orthogonal components of the angular momentum. No double electron spin gyromagnetic ratio is required to account for the observed magnetic moments, and the behavior of the atom in a magnetic field is described entirely in kinetic terms.

  18. Cluster analysis applied to the spatial and temporal variability of monthly rainfall in Mato Grosso do Sul State, Brazil

    NASA Astrophysics Data System (ADS)

    Teodoro, Paulo Eduardo; de Oliveira-Júnior, José Francisco; da Cunha, Elias Rodrigues; Correa, Caio Cezar Guedes; Torres, Francisco Eduardo; Bacani, Vitor Matheus; Gois, Givanildo; Ribeiro, Larissa Pereira

    2016-04-01

    The State of Mato Grosso do Sul (MS) located in Brazil Midwest is devoid of climatological studies, mainly in the characterization of rainfall regime and producers' meteorological systems and rain inhibitors. This state has different soil and climatic characteristics distributed among three biomes: Cerrado, Atlantic Forest and Pantanal. This study aimed to apply the cluster analysis using Ward's algorithm and identify those meteorological systems that affect the rainfall regime in the biomes. The rainfall data of 32 stations (sites) of the MS State were obtained from the Agência Nacional de Águas (ANA) database, collected from 1954 to 2013. In each of the 384 monthly rainfall temporal series was calculated the average and applied the Ward's algorithm to identify spatial and temporal variability of rainfall. Bartlett's test revealed only in January homogeneous variance at all sites. Run test showed that there was no increase or decrease in trend of monthly rainfall. Cluster analysis identified five rainfall homogeneous regions in the MS State, followed by three seasons (rainy, transitional and dry). The rainy season occurs during the months of November, December, January, February and March. The transitional season ranges between the months of April and May, September and October. The dry season occurs in June, July and August. The groups G1, G4 and G5 are influenced by South Atlantic Subtropical Anticyclone (SASA), Chaco's Low (CL), Bolivia's High (BH), Low Levels Jet (LLJ) and South Atlantic Convergence Zone (SACZ) and Maden-Julian Oscillation (MJO). Group G2 is influenced by Upper Tropospheric Cyclonic Vortex (UTCV) and Front Systems (FS). The group G3 is affected by UTCV, FS and SACZ. The meteorological systems' interaction that operates in each biome and the altitude causes the rainfall spatial and temporal diversity in MS State.

  19. Evaluation of clip localization for different kilovoltage imaging modalities as applied to partial breast irradiation setup

    SciTech Connect

    Buehler, Andreas; Ng, Sook-Kien; Lyatskaya, Yulia; Stsepankou, Dzmitry; Hesser, Jurgen; Zygmanski, Piotr

    2009-03-15

    Surgical clip localization and image quality were evaluated for different types of kilovoltage cone beam imaging modalities as applied to partial breast irradiation (PBI) setup. These modalities included (i) clinically available radiographs and cone beam CT (CB-CT) and (ii) various alternative modalities based on partial/sparse/truncated CB-CT. An anthropomorphic torso-breast phantom with surgical clips was used for the imaging studies. The torso phantom had artificial lungs, and the attached breast phantom was a mammographic phantom with realistic shape and tissue inhomogeneities. Three types of clips of variable size were used in two orthogonal orientations to assess their in-/cross-plane characteristics for image-guided setup of the torso-breast phantom in supine position. All studies were performed with the Varian on-board imaging (OBI, Varian) system. CT reconstructions were calculated with the standard Feldkamp-Davis-Kress algorithm. First, the radiographs were studied for a wide range of viewing angles to characterize image quality for various types of body anatomy in the foreground/background of the clips. Next, image reconstruction quality was evaluated for partial/sparse/truncated CB-CT. Since these modalities led to reconstructions with strong artifacts due to insufficient input data, a knowledge-based CT reconstruction method was also tested. In this method, the input data to the reconstruction algorithm were modified by combining complementary data sets selected from the treatment and reference projections. Different partial/sparse/truncated CB-CT scan types were studied depending on the total arc angle, angular increment between the consequent views (CT projections), orientation of the arc center with respect to the imaged breast and chest wall, and imaging field size. The central angles of the viewing arcs were either tangential or orthogonal to the chest wall. Several offset positions of the phantom with respect to the reference position were

  20. A comparative study of local galaxy clusters - I. Derived X-ray observables

    NASA Astrophysics Data System (ADS)

    Rozo, E.; Rykoff, E. S.; Bartlett, J. G.; Evrard, A.

    2014-02-01

    We examine systematic differences in the derived X-ray properties of galaxy clusters as reported by three different groups: Vikhlinin et al., Mantz et al. and Plank Collaboration. The sample overlap between any two pairs of works ranges between 16 to 28 galaxy clusters. We find systematic differences in most reported X-ray properties, including the total cluster mass, M500. The most extreme case is an average 45 ± 5 per cent difference in cluster mass between the Plank Collaboration and Mantz et al., for clusters at z > 0.13 (averaged over 16 clusters). These differences also induce differences in cluster observables defined within an R500 aperture. After accounting for aperture differences, we find very good agreement in gas mass estimates between the different groups. However, the soft-band X-ray luminosity, LX, core-excised spectroscopic temperature, TX, and gas thermal energy, YX = MgasTX display mean differences at the 5-15 per cent level. We also find that the low (z ≤ 0.13) and high (z ≥ 0.13) redshift galaxy cluster samples in Plank Collaboration appear to be systematically different: the YSZ/YX ratio for each of these two sub-samples is ln (YSZ/YX) = -0.06 ± 0.04 and ln (YSZ/YX) = 0.08 ± 0.04, respectively.

  1. Changes in cluster magnetism and suppression of local superconductivity in amorphous FeCrB alloy irradiated by Ar+ ions

    NASA Astrophysics Data System (ADS)

    Okunev, V. D.; Samoilenko, Z. A.; Szymczak, H.; Szewczyk, A.; Szymczak, R.; Lewandowski, S. J.; Aleshkevych, P.; Malinowski, A.; Gierłowski, P.; Więckowski, J.; Wolny-Marszałek, M.; Jeżabek, M.; Varyukhin, V. N.; Antoshina, I. A.

    2016-02-01

    We show that сluster magnetism in ferromagnetic amorphous Fe67Cr18B15 alloy is related to the presence of large, D=150-250 Å, α-(Fe Cr) clusters responsible for basic changes in cluster magnetism, small, D=30-100 Å, α-(Fe, Cr) and Fe3B clusters and subcluster atomic α-(Fe, Cr, B) groupings, D=10-20 Å, in disordered intercluster medium. For initial sample and irradiated one (Φ=1.5×1018 ions/cm2) superconductivity exists in the cluster shells of metallic α-(Fe, Cr) phase where ferromagnetism of iron is counterbalanced by antiferromagnetism of chromium. At Φ=3×1018 ions/cm2, the internal stresses intensify and the process of iron and chromium phase separation, favorable for mesoscopic superconductivity, changes for inverse one promoting more homogeneous distribution of iron and chromium in the clusters as well as gigantic (twice as much) increase in density of the samples. As a result, in the cluster shells ferromagnetism is restored leading to the increase in magnetization of the sample and suppression of local superconductivity. For initial samples, the temperature dependence of resistivity ρ(T) T2 is determined by the electron scattering on quantum defects. In strongly inhomogeneous samples, after irradiation by fluence Φ=1.5×1018 ions/cm2, the transition to a dependence ρ(T) T1/2 is caused by the effects of weak localization. In more homogeneous samples, at Φ=3×1018 ions/cm2, a return to the dependence ρ(T) T2 is observed.

  2. Characterizing the local solvation environment of OH(-) in water clusters with AIMD.

    PubMed

    Crespo, Yanier; Hassanali, Ali

    2016-02-21

    In this work, we use ab initio molecular dynamics coupled with metadynamics to explore and characterize the glassy potential energy landscape of the OH(-) in a 20 and 48 water cluster. The structural, energetic, and topological properties of OH(-) are characterized for both clusters and the molecular origins of the IR signatures are examined. We find that in both the small and large clusters, the OH(-) can donate or accept a varying number of hydrogen bonds confirming that the amphiphilic character does not depend on cluster size. However, we highlight some important differences found between the energetic and topological properties of both families of clusters which may have implications on understanding the changes in the solvation structure of OH(-) between bulk and interfacial environments. By studying the IR spectra of smaller subsets of molecules within the 20 water molecule cluster, we find that the IR spectrum of the bare OH(-) as well as the water molecule donating a strong hydrogen bond to it exhibits characteristic absorption along the amphiphilic band between 1500 and 3000 cm(-1) at positions very similar to those found for the entire hydroxide cluster. The results presented here will be useful in the calibration and improvement of both ab initio and semi-empirical methods to model this complex anion.

  3. Applying the balanced scorecard to local public health performance measurement: deliberations and decisions

    PubMed Central

    Weir, Erica; d'Entremont, Nadine; Stalker, Shelley; Kurji, Karim; Robinson, Victoria

    2009-01-01

    Background All aspects of the heath care sector are being asked to account for their performance. This poses unique challenges for local public health units with their traditional focus on population health and their emphasis on disease prevention, health promotion and protection. Reliance on measures of health status provides an imprecise and partial picture of the performance of a health unit. In 2004 the provincial Institute for Clinical Evaluative Sciences based in Ontario, Canada introduced a public-health specific balanced scorecard framework. We present the conceptual deliberations and decisions undertaken by a health unit while adopting the framework. Discussion Posing, pondering and answering key questions assisted in applying the framework and developing indicators. Questions such as: Who should be involved in developing performance indicators? What level of performance should be measured? Who is the primary intended audience? Where and how do we begin? What types of indicators should populate the health status and determinants quadrant? What types of indicators should populate the resources and services quadrant? What type of indicators should populate the community engagement quadrant? What types of indicators should populate the integration and responsiveness quadrants? Should we try to link the quadrants? What comparators do we use? How do we move from a baseline report card to a continuous quality improvement management tool? Summary An inclusive, participatory process was chosen for defining and creating indicators to populate the four quadrants. Examples of indicators that populate the four quadrants of the scorecard are presented and key decisions are highlighted that facilitated the process. PMID:19426508

  4. Perilymph pharmacokinetics of locally-applied gentamicin in the guinea pig.

    PubMed

    Salt, A N; Hartsock, J J; Gill, R M; King, E; Kraus, F B; Plontke, S K

    2016-12-01

    Intratympanic gentamicin therapy is widely used clinically to suppress the vestibular symptoms of Meniere's disease. Dosing in humans was empirically established and we still know remarkably little about where gentamicin enters the inner ear, where it reaches in the inner ear and what time course it follows after local applications. In this study, gentamicin was applied to the round window niche as a 20 μL bolus of 40 mg/ml solution. Ten 2 μL samples of perilymph were collected sequentially from the lateral semi-circular canal (LSCC) at times from 1 to 4 h after application. Gentamicin concentration was typically highest in samples originating from the vestibule and was lower in samples originating from scala tympani. To interpret these results, perilymph elimination kinetics for gentamicin was quantified by loading the entire perilymph space by injection at the LSCC with a 500 μg/ml gentamicin solution followed by sequential perilymph sampling from the LSCC after different delay times. This allowed concentration decline in perilymph to be followed with time. Gentamicin was retained well in scala vestibuli and the vestibule but declined rapidly at the base of scala tympani, dominated by interactions of perilymph with CSF, as reported for other substances. Quantitative analysis, taking into account perilymph kinetics for gentamicin, showed that more gentamicin entered at the round window membrane (57%) than at the stapes (35%) but the lower concentrations found in scala tympani were due to greater losses there. The gentamicin levels found in perilymph of the vestibule, which are higher than would be expected from round window entry alone, undoubtedly contribute to the vestibulotoxic effects of the drug. Furthermore, calculations of gentamicin distribution following targeted applications to the RW or stapes are more consistent with cochleotoxicity depending on the gentamicin concentration in scala vestibuli rather than that in scala tympani.

  5. Automatic categorization of anatomical landmark-local appearances based on diffeomorphic demons and spectral clustering for constructing detector ensembles.

    PubMed

    Hanaoka, Shouhei; Masutani, Yoshitaka; Nemoto, Mitsutaka; Nomura, Yukihiro; Yoshikawa, Takeharu; Hayashi, Naoto; Ohtomo, Kuni

    2012-01-01

    A method for categorizing landmark-local appearances extracted from computed tomography (CT) datasets is presented. Anatomical landmarks in the human body inevitably have inter-individual variations that cause difficulty in automatic landmark detection processes. The goal of this study is to categorize subjects (i.e., training datasets) according to local shape variations of such a landmark so that each subgroup has less shape variation and thus the machine learning of each landmark detector is much easier. The similarity between each subject pair is measured based on the non-rigid registration result between them. These similarities are used by the spectral clustering process. After the clustering, all training datasets in each cluster, as well as synthesized intermediate images calculated from all subject-pairs in the cluster, are used to train the corresponding subgroup detector. All of these trained detectors compose a detector ensemble to detect the target landmark. Evaluation with clinical CT datasets showed great improvement in the detection performance.

  6. A new co-operative inversion strategy via fuzzy clustering technique applied to seismic and magnetotelluric data

    NASA Astrophysics Data System (ADS)

    Thong Kieu, Duy; Kepic, Anton

    2015-04-01

    Geophysical inversion produces very useful images of earth parameters; however, inversion results usually suffer from inherent non-uniqueness: many subsurface models with different structures and parameters can explain the measurements. To reduce the ambiguity, extra information about the earth's structure and physical properties is needed. This prior information can be extracted from geological principles, prior petrophysical information from well logs, and complementary information from other geophysical methods. Any technique used to constrain inversion should be able to integrate the prior information and to guide updating inversion process in terms of the geological model. In this research, we have adopted fuzzy c-means (FCM) clustering technique for this purpose. FCM is a clustering method that allows us to divide the model of physical parameters into a few clusters of representative values that also may relate to geological units based on the similarity of the geophysical properties. This exploits the fact that in many geological environments the earth is comprised of a few distinctive rock units with different physical properties. Therefore FCM can provide a platform to constrain geophysical inversion, and should tend to produce models that are geologically meaningful. FCM was incorporated in both separate and co-operative inversion processing of seismic and magnetotelluric (MT) data with petrophysical constraints. Using petrophysical information through FCM assists the inversion to build a reliable earth model. In this algorithm, FCM plays a role of guider; it uses the prior information to drive the model update process, and also forming an earth model filled with rocks units rather than smooth transitions when the boundary is in doubt. Where petrophysical information from well logs or core measurement is not locally available the cluster petrophysics may be solved for in inversion as well if some knowledge of how many distinctive geological exist. A

  7. Applying a Generic Juvenile Risk Assessment Instrument to a Local Context: Some Practical and Theoretical Lessons

    ERIC Educational Resources Information Center

    Miller, Joel; Lin, Jeffrey

    2007-01-01

    This article examines issues raised by the application of a generic actuarial juvenile risk instrument (the Model Risk Assessment Instrument) to New York City, a context different from the one in which it was developed. It describes practical challenges arising from the constraints of locally available data and local sensibilities and highlights…

  8. A refined cluster-in-molecule local correlation approach for predicting the relative energies of large systems.

    PubMed

    Li, Wei; Guo, Yang; Li, Shuhua

    2012-06-07

    A refined cluster-in-molecule (CIM) method for local correlation calculations of large molecules is presented. In the present work, two new strategies are introduced to further improve the CIM approach: (1) Some medium-range electron correlation energies, which are neglected in the previous CIM approach, are taken into account. (2) A much simpler procedure using only a distance threshold is used to construct various clusters. To cover the medium-range correlation effect as much as possible, some two-atom-centered clusters are built, in addition to one-atom-centered clusters. Our test calculations at the second order perturbation theory (MP2) level show that the refined CIM method can recover about 99.9% of the conventional MP2 correlation energy using an appropriate distance threshold. The accuracy of the present CIM method is capable of providing reliable relative energies of medium-sized systems such as polyalanines with 10 residues, and water molecules with 50 water molecules. For polyalanines with up to 30 residues, we have demonstrated that the computational cost of the CIM-MP2 calculation increases linearly with the molecular size, but the required memory and disc-space do not need to increase for large systems. The improved CIM method has been used to compute the relative energy of ice-like (H(2)O)(96) clusters (with 2400 basis functions) and to predict the dimerization energy of a double-helical foldamer (with 2330 basis functions). The present CIM method is expected to be a practical local correlation method for describing the relative energies of large systems.

  9. Coordinate-Based Clustering Method for Indoor Fingerprinting Localization in Dense Cluttered Environments.

    PubMed

    Liu, Wen; Fu, Xiao; Deng, Zhongliang

    2016-12-02

    Indoor positioning technologies has boomed recently because of the growing commercial interest in indoor location-based service (ILBS). Due to the absence of satellite signal in Global Navigation Satellite System (GNSS), various technologies have been proposed for indoor applications. Among them, Wi-Fi fingerprinting has been attracting much interest from researchers because of its pervasive deployment, flexibility and robustness to dense cluttered indoor environments. One challenge, however, is the deployment of Access Points (AP), which would bring a significant influence on the system positioning accuracy. This paper concentrates on WLAN based fingerprinting indoor location by analyzing the AP deployment influence, and studying the advantages of coordinate-based clustering compared to traditional RSS-based clustering. A coordinate-based clustering method for indoor fingerprinting location, named Smallest-Enclosing-Circle-based (SEC), is then proposed aiming at reducing the positioning error lying in the AP deployment and improving robustness to dense cluttered environments. All measurements are conducted in indoor public areas, such as the National Center For the Performing Arts (as Test-bed 1) and the XiDan Joy City (Floors 1 and 2, as Test-bed 2), and results show that SEC clustering algorithm can improve system positioning accuracy by about 32.7% for Test-bed 1, 71.7% for Test-bed 2 Floor 1 and 73.7% for Test-bed 2 Floor 2 compared with traditional RSS-based clustering algorithms such as K-means.

  10. Coordinate-Based Clustering Method for Indoor Fingerprinting Localization in Dense Cluttered Environments

    PubMed Central

    Liu, Wen; Fu, Xiao; Deng, Zhongliang

    2016-01-01

    Indoor positioning technologies has boomed recently because of the growing commercial interest in indoor location-based service (ILBS). Due to the absence of satellite signal in Global Navigation Satellite System (GNSS), various technologies have been proposed for indoor applications. Among them, Wi-Fi fingerprinting has been attracting much interest from researchers because of its pervasive deployment, flexibility and robustness to dense cluttered indoor environments. One challenge, however, is the deployment of Access Points (AP), which would bring a significant influence on the system positioning accuracy. This paper concentrates on WLAN based fingerprinting indoor location by analyzing the AP deployment influence, and studying the advantages of coordinate-based clustering compared to traditional RSS-based clustering. A coordinate-based clustering method for indoor fingerprinting location, named Smallest-Enclosing-Circle-based (SEC), is then proposed aiming at reducing the positioning error lying in the AP deployment and improving robustness to dense cluttered environments. All measurements are conducted in indoor public areas, such as the National Center For the Performing Arts (as Test-bed 1) and the XiDan Joy City (Floors 1 and 2, as Test-bed 2), and results show that SEC clustering algorithm can improve system positioning accuracy by about 32.7% for Test-bed 1, 71.7% for Test-bed 2 Floor 1 and 73.7% for Test-bed 2 Floor 2 compared with traditional RSS-based clustering algorithms such as K-means. PMID:27918454

  11. Spectroscopic Study of Local Interactions of Platinum in Small [CexOy]Ptx' - Clusters

    NASA Astrophysics Data System (ADS)

    Ray, Manisha; Kafader, Jared O.; Chick Jarrold, Caroline

    2016-06-01

    Cerium oxide is a good ionic conductor, and the conductivity can be enhanced with oxygen vacancies and doping. This conductivity may play an important role in the enhancement of noble or coinage metal toward the water-gas shift reaction when supported by cerium oxide. The ceria-supported platinum catalyst in particular has received much attention because of higher activity at lower temperatures (LT) compared to the most common commercial LT-WGS catalyst. We have used a combination of anion photoelectron spectroscopy and density functional theory calculations to study the interesting molecular and electronic structures and properties of cluster models of ceria-supported platinum. [CexOy]Ptx' - (x,x'=1,2 ; y≤2x') clusters exhibit evidence of ionic bonding possible because of the high electron affinity of Pt and the low ionization potential of cerium oxide clusters. In addition, Pt- is a common daughter ion resulting from photodissociation of [CexOy]Ptx' - clusters. Finally, several of the anion and neutral clusters have profoundly different structures. These features may play a role in the enhancement of catalytic activity toward the water-gas shift reaction.

  12. The Adult Learner and the Applied Baccalaureate: Emerging Lessons for State and Local Implementation. In Brief

    ERIC Educational Resources Information Center

    Bragg, Debra D.; Townsend, Barbara K.; Ruud, Collin M.

    2009-01-01

    In the nation's changing economy, there is an increasing necessity for baccalaureate level education for jobs that have never before required that level of education. One potential solution to issues related to baccalaureate attainment and workforce development is the applied baccalaureate degree. Applied baccalaureate degrees have arisen from a…

  13. Dynamic regional phase synchrony (DRePS): An Instantaneous Measure of Local fMRI Connectivity Within Spatially Clustered Brain Areas.

    PubMed

    Omidvarnia, Amir; Pedersen, Mangor; Walz, Jennifer M; Vaughan, David N; Abbott, David F; Jackson, Graeme D

    2016-05-01

    Dynamic functional brain connectivity analysis is a fast expanding field in computational neuroscience research with the promise of elucidating brain network interactions. Sliding temporal window based approaches are commonly used in order to explore dynamic behavior of brain networks in task-free functional magnetic resonance imaging (fMRI) data. However, the low effective temporal resolution of sliding window methods fail to capture the full dynamics of brain activity at each time point. These also require subjective decisions regarding window size and window overlap. In this study, we introduce dynamic regional phase synchrony (DRePS), a novel analysis approach that measures mean local instantaneous phase coherence within adjacent fMRI voxels. We evaluate the DRePS framework on simulated data showing that the proposed measure is able to estimate synchrony at higher temporal resolution than sliding windows of local connectivity. We applied DRePS analysis to task-free fMRI data of 20 control subjects, revealing ultra-slow dynamics of local connectivity in different brain areas. Spatial clustering based on the DRePS feature time series reveals biologically congruent local phase synchrony networks (LPSNs). Taken together, our results demonstrate three main findings. Firstly, DRePS has increased temporal sensitivity compared to sliding window correlation analysis in capturing locally synchronous events. Secondly, DRePS of task-free fMRI reveals ultra-slow fluctuations of ∼0.002-0.02 Hz. Lastly, LPSNs provide plausible spatial information about time-varying brain local phase synchrony. With the DRePS method, we introduce a framework for interrogating brain local connectivity, which can potentially provide biomarkers of human brain function in health and disease. Hum Brain Mapp 37:1970-1985, 2016. © 2016 Wiley Periodicals, Inc.

  14. Clustering with position-specific constraints on variance: applying redescending M-estimators to label-free LC-MS data analysis.

    PubMed

    Frühwirth, Rudolf; Mani, D R; Pyne, Saumyadipta

    2011-08-31

    Clustering is a widely applicable pattern recognition method for discovering groups of similar observations in data. While there are a large variety of clustering algorithms, very few of these can enforce constraints on the variation of attributes for data points included in a given cluster. In particular, a clustering algorithm that can limit variation within a cluster according to that cluster's position (centroid location) can produce effective and optimal results in many important applications ranging from clustering of silicon pixels or calorimeter cells in high-energy physics to label-free liquid chromatography based mass spectrometry (LC-MS) data analysis in proteomics and metabolomics. We present MEDEA (M-Estimator with DEterministic Annealing), an M-estimator based, new unsupervised algorithm that is designed to enforce position-specific constraints on variance during the clustering process. The utility of MEDEA is demonstrated by applying it to the problem of "peak matching"--identifying the common LC-MS peaks across multiple samples--in proteomic biomarker discovery. Using real-life datasets, we show that MEDEA not only outperforms current state-of-the-art model-based clustering methods, but also results in an implementation that is significantly more efficient, and hence applicable to much larger LC-MS data sets. MEDEA is an effective and efficient solution to the problem of peak matching in label-free LC-MS data. The program implementing the MEDEA algorithm, including datasets, clustering results, and supplementary information is available from the author website at http://www.hephy.at/user/fru/medea/.

  15. The efficacy of locally applied morphine in post-operative pain after bilateral third molar surgery.

    PubMed

    Moore, U J; Seymour, R A; Gilroy, J; Rawlins, M D

    1994-03-01

    1. Recent evidence has hinted at a peripheral site of action of morphine analgesic efficacy. 2. Previous studies by the same authors have developed a model for testing local analgesic efficacy by placing drugs into tooth sockets after third molar surgery. 3. The present studies test the hypothesis of local morphine activity at two dosage concentrations, 100 ng ml-1 and 100 micrograms ml-1 after third molar surgery. 4. No significant analgesic efficacy was found at either dose when compared with placebo.

  16. New Theoretical Developments in Exploring Electronically Excited States: Including Localized Configuration Interaction Singles and Application to Large Helium Clusters

    NASA Astrophysics Data System (ADS)

    Closser, Kristina Danielle

    superpositions of atomic states with surface states appearing close to the atomic excitation energies and interior states being blue shifted by up to ≈2 eV. The dynamics resulting from excitation of He_7 were subsequently explored using ab initio molecular dynamics (AIMD). These simulations were performed with classical adiabatic dynamics coupled to a new state-following algorithm on CIS potential energy surfaces. Most clusters were found to completely dissociate and resulted in a single excited atomic state (90%), however, some trajectories formed bound, He*2 (3%), and a few yielded excited trimers (<0.5%). Comparisons were made with available experimental information on much larger clusters. Various applications of this state following algorithm are also presented. In addition to AIMD, these include excited-state geometry optimization and minimal energy path finding via the growing string method. When using state following we demonstrate that more physical results can be obtained with AIMD calculations. Also, the optimized geometries of three excited states of cytosine, two of which were not found without state following, and the minimal energy path between the lowest two singlet excited states of protonated formaldimine are offered as example applications. Finally, to address large clusters, a local variation of CIS was developed. This method exploits the properties of absolutely localized molecular orbitals (ALMOs) to limit the total number of excitations to scaling only linearly with cluster size, which results in formal scaling with the third power of the system size. The derivation of the equations and design of the algorithm are discussed in detail, and computational timings as well as a pilot application to the size dependence of the helium cluster spectrum are presented.

  17. Canada's experience in applying C&I to measure progress towards SFM - perspectives from the National, Regional and local levels

    Treesearch

    John E. Hall; S. R. J. Bridge; Brian D. Haddon

    2006-01-01

    This paper will provide perspectives of Canada’s experiences in applying Criteria and Indicators (C&I) to measure progress towards Sustainable Forest Management (SFM) at the National, Regional (Provincial) and local levels. SFM is rooted in Bruntland’s concept of Sustainable Development and is about providing for present forest-based needs without compromising...

  18. 34 CFR 222.83 - How does an eligible local educational agency apply for a payment under section 8003(g)?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 34 Education 1 2010-07-01 2010-07-01 false How does an eligible local educational agency apply for a payment under section 8003(g)? 222.83 Section 222.83 Education Regulations of the Offices of the Department of Education OFFICE OF ELEMENTARY AND SECONDARY EDUCATION, DEPARTMENT OF EDUCATION IMPACT...

  19. 34 CFR 222.62 - Which local educational agencies are eligible to apply for an additional payment under section...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... for an additional payment under section 8003(f)? 222.62 Section 222.62 Education Regulations of the... Section 8003(f) of the Act § 222.62 Which local educational agencies are eligible to apply for an... percent of the average tax rate of generally comparable LEAs identified under §§ 222.39-222.41 or...

  20. 34 CFR 222.83 - How does an eligible local educational agency apply for a payment under section 8003(g)?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... a payment under section 8003(g)? 222.83 Section 222.83 Education Regulations of the Offices of the...) of the Act § 222.83 How does an eligible local educational agency apply for a payment under section... in § 222.81, during the LEA's preceding fiscal year, including the following: (1) For the costs...

  1. Fragment-Based Direct-Local-Ring-Coupled-Cluster Doubles Treatment Embedded in the Periodic Hartree-Fock Solution.

    PubMed

    Masur, Oliver; Schütz, Martin; Maschio, Lorenzo; Usvyat, Denis

    2016-10-11

    We present a periodic/finite-cluster interface for fragment-based direct local ring-coupled-cluster doubles (d-LrCCD) calculations embedded in the periodic mean field. The fragment is defined by a set of Wannier functions (WFs), obtained from a periodic Hartree-Fock calculation. The pair-specific virtual space is spanned by projected atomic orbitals (PAOs) truncated to pair domains. The computational procedure is initiated by a periodic local Møller-Plesset (LMP2) calculation. A subset of the WF pairs is then subsequently subjected to a finite-cluster d-LrCCD treatment using the local coupled cluster program of Molpro; this subset is specified by an interorbital cutoff distance. The orbital, pair, and domain lists, as well as other essential quantities needed for d-LrCCD such as the Fock and overlap matrices, and the electron repulsion integrals (ERIs) in the basis of WFs and PAOs are evaluated in the periodic framework and passed to Molpro via an interface. These periodic quantities provide the correct periodic mean-field embedding for the fragment d-LrCCD. Moreover, no expensive orbital transformations involving orbital coefficients related to large supporting clusters are necessary. ERIs appearing in the d-LrCCD diagrams are factorized via density fitting, which enables an efficient processing of the corresponding terms via three-index intermediates. The corresponding 3-index and the metric 2-index ERIs involving auxiliary functions are also computed and transformed to the WF-PAO basis (the 3-index ERI) on the periodic side. Although the direct ring-CCD method itself is not generally more accurate than MP2, it is more stable in the case of small band gap systems, as it sums up the ring diagrams to infinite order. Furthermore, this interface is a first step toward a high-level fragment-based quantum chemical treatment such as local CCSD(T) within a periodic embedding that is treated at a lower level. As two test examples we study the physisorption of H2 and

  2. Quantum Cluster Equilibrium Theory Applied in Hydrogen Bond Number Studies of Water. 2. Icebergs in a Two-Dimensional Water Continuum?

    PubMed

    Lehmann, S B C; Spickermann, C; Kirchner, B

    2009-06-09

    With the aid of the quantum cluster equilibrium method, we calculate thermodynamic properties for a new water cluster set containing 2-fold and additional tetrahedrally hydrogen-bonded water molecules on the basis of accurate correlated electronic structure calculations. The addition of clusters with 4-fold coordinated water molecules leads to an improved thermodynamical description of the liquid phase in comparison to experimental values. The comparison of the obtained isobars from the pure 2-fold cluster set with the mixed cluster set shows improved results for the mixed set. Furthermore, the results of the liquid-phase entropy calculation compare excellently with experiment if the mixed cluster set is applied. The calculated populations allow us to determine hydrogen bond numbers, resulting in a temperature-dependent average hydrogen bond number. We observe a decreasing average hydrogen bond number of 2.77 at 274 K to 2.26 at 373 K and a dominance of 75% 2-fold hydrogen-bonded water molecules at room temperature for the mixed cluster set.

  3. Characterising the local void with the X-ray cluster survey REFLEX II

    NASA Astrophysics Data System (ADS)

    Collins, Chris A.; Böhringer, Hans; Bristow, Martyn; Chon, Gayoung

    2016-10-01

    Claims of a significant underdensity or void in the density distribution on scales out to ~= 300 Mpc have recently been made using samples of galaxies. We present the results of an alternative test of the matter distribution on these scales using clusters of galaxies, which provide an independent and powerful probe of large-scale structure. We study the density distribution of X-ray clusters from the ROSAT-based REFLEX II catalogue, which covers a contiguous area of 4.24 steradians in the southern hempsphere (34% of the entire sky). Using the normalised comoving number density of clusters we find evidence for an underdensity (30-40%), out to z~ 0.04, equivalent to ~=170 Mpc and with a significance of 3.4σ. On scales between 300 Mpc and 1 Gpc the distribution of REFLEX II clusters is consistent with being uniform. We also confirm recent results that the underdensity has a large contribution from the direction of the South Galactic Cap region, but is not significant in the direction of the Northern Galactic Cap as viewed from the southern sky. Both the limited size of the detected underdensity and its lack of isotropy, argue against the idea that the Type Ia supernovae data can be explained without the need for dark energy.

  4. Genetic localization and in vivo characterization of a Monascus azaphilone pigment biosynthetic gene cluster.

    PubMed

    Balakrishnan, Bijinu; Karki, Suman; Chiu, Shih-Hau; Kim, Hyun-Ju; Suh, Jae-Won; Nam, Bora; Yoon, Yeo-Min; Chen, Chien-Chi; Kwon, Hyung-Jin

    2013-07-01

    Monascus spp. produce several well-known polyketides such as monacolin K, citrinin, and azaphilone pigments. In this study, the azaphilone pigment biosynthetic gene cluster was identified through T-DNA random mutagenesis in Monascus purpureus. The albino mutant W13 bears a T-DNA insertion upstream of a transcriptional regulator gene (mppR1). The transcription of mppR1 and the nearby polyketide synthase gene (MpPKS5) was significantly repressed in the W13 mutant. Targeted inactivation of MpPKS5 also gave rise to an albino mutant, confirming that mppR1 and MpPKS5 belong to an azaphilone pigment biosynthetic gene cluster. This M. purpureus sequence was used to identify the whole biosynthetic gene cluster in the Monascus pilosus genome. MpPKS5 contains SAT/KS/AT/PT/ACP/MT/R domains, and this domain organization is preserved in other azaphilone polyketide synthases. This biosynthetic gene cluster also encodes fatty acid synthase (FAS), which is predicted to assist the synthesis of 3-oxooactanoyl-CoA and 3-oxodecanoyl-CoA. These 3-oxoacyl compounds are proposed to be incorporated into the azaphilone backbone to complete the pigment biosynthesis. A monooxygenase gene (an azaH and tropB homolog) that is located far downstream of the FAS gene is proposed to be involved in pyrone ring formation. A homology search on other fungal genome sequences suggests that this azaphilone pigment gene cluster also exists in the Penicillium marneffei and Talaromyces stipitatus genomes.

  5. Country clustering applied to the water and sanitation sector: a new tool with potential applications in research and policy.

    PubMed

    Onda, Kyle; Crocker, Jonny; Kayser, Georgia Lyn; Bartram, Jamie

    2014-03-01

    The fields of global health and international development commonly cluster countries by geography and income to target resources and describe progress. For any given sector of interest, a range of relevant indicators can serve as a more appropriate basis for classification. We create a new typology of country clusters specific to the water and sanitation (WatSan) sector based on similarities across multiple WatSan-related indicators. After a literature review and consultation with experts in the WatSan sector, nine indicators were selected. Indicator selection was based on relevance to and suggested influence on national water and sanitation service delivery, and to maximize data availability across as many countries as possible. A hierarchical clustering method and a gap statistic analysis were used to group countries into a natural number of relevant clusters. Two stages of clustering resulted in five clusters, representing 156 countries or 6.75 billion people. The five clusters were not well explained by income or geography, and were distinct from existing country clusters used in international development. Analysis of these five clusters revealed that they were more compact and well separated than United Nations and World Bank country clusters. This analysis and resulting country typology suggest that previous geography- or income-based country groupings can be improved upon for applications in the WatSan sector by utilizing globally available WatSan-related indicators. Potential applications include guiding and discussing research, informing policy, improving resource targeting, describing sector progress, and identifying critical knowledge gaps in the WatSan sector.

  6. Looking under the Bushels: Schools Still Applying Local Solutions to National Teacher Recruitment Problem.

    ERIC Educational Resources Information Center

    Traviss, Sister Mary Peter

    2001-01-01

    Discusses the national teacher shortage in Catholic schools. Reports findings from a survey of Catholic school superintendents conducted by the Chief Administrators of Catholic Education. Found that the most effective recruitment efforts were schools seeking teachers from within local communities through parish bulletins and word of mouth. (CJW)

  7. Looking under the Bushels: Schools Still Applying Local Solutions to National Teacher Recruitment Problem.

    ERIC Educational Resources Information Center

    Traviss, Sister Mary Peter

    2001-01-01

    Discusses the national teacher shortage in Catholic schools. Reports findings from a survey of Catholic school superintendents conducted by the Chief Administrators of Catholic Education. Found that the most effective recruitment efforts were schools seeking teachers from within local communities through parish bulletins and word of mouth. (CJW)

  8. Slow Quenching of Star Formation in OMEGAWINGS Clusters: Galaxies in Transition in the Local Universe

    NASA Astrophysics Data System (ADS)

    Paccagnella, A.; Vulcani, B.; Poggianti, B. M.; Moretti, A.; Fritz, J.; Gullieuszik, M.; Couch, W.; Bettoni, D.; Cava, A.; D'Onofrio, M.; Fasano, G.

    2016-01-01

    The star formation quenching depends on environment, but a full understanding of what mechanisms drive it is still missing. Exploiting a sample of galaxies with masses {M}*\\gt {10}9.8{M}⊙ , drawn from the WIde-field Nearby Galaxy-cluster Survey (WINGS) and its recent extension OMEGAWINGS, we investigate the star formation rate (SFR) as a function of stellar mass (M{}*) in galaxy clusters at 0.04\\lt z\\lt 0.07. We use non-member galaxies at 0.02 < z < 0.09 as a field control sample. Overall, we find agreement between the SFR-M{}* relation in the two environments, but detect a population of cluster galaxies with reduced SFRs, which is rare in the field. These transition galaxies are mainly found within the cluster virial radius (R200), but they impact on the SFR-M{}* relation only within 0.6R200. The ratio of transition to pure star-forming galaxies strongly depends on environment, being larger than 0.6 within 0.3R200 and rapidly decreasing with distance, while it is almost flat with M*. As galaxies move downward from the SFR-M{}* main sequence, they become redder and present older luminosity- and mass-weighted ages. These trends, together with the analysis of the star formation histories, suggest that transition galaxies have had a reduced SFR for the past 2-5 Gyr. Our results are consistent with the hypothesis that the interaction of galaxies with the intracluster medium via strangulation causes a gradual shut down of star formation, giving birth to an evolved population of galaxies in transition from being star forming to becoming passive.

  9. Localization of the X-ray source in the globular cluster G1 with Chandra

    NASA Astrophysics Data System (ADS)

    Kong, A. K. H.; Heinke, C. O.; di Stefano, R.; Cohn, H. N.; Lugger, P. M.; Barmby, P.; Lewin, W. H. G.; Primini, F. A.

    2010-09-01

    We report the most accurate X-ray position of the X-ray source in the giant globular cluster G1 in M31 by using the Chandra X-ray Observatory, Hubble Space Telescope (HST) and Canada-France-Hawaii Telescope (CFHT). G1 is clearly detected with Chandra and by cross-registering with HST and CFHT images, we derive a 1σ error radius of 0.15arcsec, significantly smaller than the previous measurement by XMM-Newton. We conclude that the X-ray emission of G1 is likely to come from within the core radius of the cluster. We have considered a number of possibilities for the origin of the X-ray emission but can rule all but two scenarios out: it could be due to either accretion on to a central intermediate-mass black hole (IMBH) or an ordinary low-mass X-ray binary (LMXB). Based on the X-ray luminosity and the Bondi accretion rate, an IMBH accreting from the cluster gas seems unlikely and we suggest that the X-rays are due to accretion from a companion. Alternatively, the probability that a 1.5 Msolar cluster LMXB lies within the 95 per cent X-ray error circle is about 0.7. Therefore we cannot rule out a single LMXB as the origin of the X-ray emission. While we cannot distinguish between different models with current observations, future high-resolution and high-sensitivity radio imaging observations will reveal whether there is an IMBH at the centre of G1.

  10. Cluster-glass behavior induced by local moment doping in the itinerant ferromagnet Sc3.1In

    NASA Astrophysics Data System (ADS)

    Svanidze, E.; Morosan, E.

    2013-08-01

    In the presented work, Sc3.1In, a weak itinerant ferromagnet with no magnetic constituents, is doped with Er3+ local moment ions, to form (Sc1-xErx)3.1In. As x increases, the Weiss-like temperature θ stays positive and nearly triples up to x=0.10. Moreover, Er doping of as little as x=0.02 induces a cluster-glass state, which persists up to x=0.10, as evidenced by dc and ac susceptibility measurements, and confirmed by the Vogel-Fulcher analysis.

  11. Understanding resonant tunnel transport in non-identical and non-aligned clusters as applied to disordered carbon systems

    SciTech Connect

    Bhattacharyya, Somnath; Churochkin, Dmitry

    2014-10-21

    We study the conductance spectra and the corresponding current-voltage characteristics of a set of three impurity clusters of different sizes arranged in the form of a scalene triangle and compare with the transport of their horizontal and vertical configurations. The tuning capability of resonant tunnelling features in a quantum dot device made of these non-aligned impurity clusters is demonstrated by re-distributing their diameters and inter-cluster distances in a systematic manner. By manipulating the inter-cluster coupling for a scalene triangular configuration, the transition of current-voltage curves from a step-like feature to a negative differential resistance can be produced. This process also yields conductance features for triangular configurations, which can be compared to the quantum dot structures perfectly aligned to the direction of the propagating wavevector. The strength of inter-cluster coupling or order parameter for these configurations is analysed from the relative variation of the width and the energy difference of the sharp and broad peaks observed in the density of states spectra. Based on the relative change of the inter-cluster coupling with the cluster configurations, a transport model applicable to structurally inhomogeneous systems is proposed in order to explain the experimentally observed variation of the energy band gap with the disorder parameters.

  12. Local SIMPLE multi-atlas-based segmentation applied to lung lobe detection on chest CT

    NASA Astrophysics Data System (ADS)

    Agarwal, M.; Hendriks, E. A.; Stoel, B. C.; Bakker, M. E.; Reiber, J. H. C.; Staring, M.

    2012-02-01

    For multi atlas-based segmentation approaches, a segmentation fusion scheme which considers local performance measures may be more accurate than a method which uses a global performance measure. We improve upon an existing segmentation fusion method called SIMPLE and extend it to be localized and suitable for multi-labeled segmentations. We demonstrate the algorithm performance on 23 CT scans of COPD patients using a leave-one- out experiment. Our algorithm performs significantly better (p < 0.01) than majority voting, STAPLE, and SIMPLE, with a median overlap of the fissure of 0.45, 0.48, 0.55 and 0.6 for majority voting, STAPLE, SIMPLE, and the proposed algorithm, respectively.

  13. Novel local rules of cellular automata applied to topology and size optimization

    NASA Astrophysics Data System (ADS)

    Bochenek, Bogdan; Tajs-Zielińska, Katarzyna

    2012-01-01

    Cellular automata are mathematical idealization of physical systems in which the design domains are divided into lattices of cells, states of which are updated synchronously in discrete time steps according to some local rules. The principle of the cellular automata is that global behaviour of the system is governed by cells that only interact with their neighbours. Because of its simplicity and versatility the method has been found as useful tool for structural design, especially that cellular automata methodology can be adopted for both optimal sizing and topology optimization. This article presents the application of the cellular automata concept to topology optimization of plane elastic structures. As to the optimal sizing, the design of columns exposed to loss of stability is also discussed. A new local update rule is proposed, selected optimal design problems are formulated, and finally the article is illustrated by results of numerical optimization.

  14. Applying local Gabor ternary pattern for video-based illumination variable face recognition

    NASA Astrophysics Data System (ADS)

    Wang, Huafeng; Han, Yong; Zhang, Zhaoxiang

    2011-12-01

    The illumination variation problem is one of the well-known problems in face recognition in uncontrolled environment. Due to that both Gabor feature and LTP(local ternary pattern) are testified to be robust to illumination variations, we proposed a new approach which achieved illumination variable face recognition by combining Gabor filters with LTP operator. The experimental results compared with the published results on Yale-B and CMU PIE face database of changing illumination verify the validity of the proposed method.

  15. Applying local Gabor ternary pattern for video-based illumination variable face recognition

    NASA Astrophysics Data System (ADS)

    Wang, Huafeng; Han, Yong; Zhang, Zhaoxiang

    2012-01-01

    The illumination variation problem is one of the well-known problems in face recognition in uncontrolled environment. Due to that both Gabor feature and LTP(local ternary pattern) are testified to be robust to illumination variations, we proposed a new approach which achieved illumination variable face recognition by combining Gabor filters with LTP operator. The experimental results compared with the published results on Yale-B and CMU PIE face database of changing illumination verify the validity of the proposed method.

  16. How to Maximally Support Local and Regional Biodiversity in Applied Conservation? Insights from Pond Management

    PubMed Central

    Lemmens, Pieter; Mergeay, Joachim; De Bie, Tom; Van Wichelen, Jeroen; De Meester, Luc; Declerck, Steven A. J.

    2013-01-01

    Biodiversity and nature values in anthropogenic landscapes often depend on land use practices and management. Evaluations of the association between management and biodiversity remain, however, comparatively scarce, especially in aquatic systems. Furthermore, studies also tend to focus on a limited set of organism groups at the local scale, whereas a multi-group approach at the landscape scale is to be preferred. This study aims to investigate the effect of pond management on the diversity of multiple aquatic organism groups (e.g. phytoplankton, zooplankton, several groups of macro-invertebrates, submerged and emergent macrophytes) at local and regional spatial scales. For this purpose, we performed a field study of 39 shallow man-made ponds representing five different management types. Our results indicate that fish stock management and periodic pond drainage are crucial drivers of pond biodiversity. Furthermore, this study provides insight in how the management of eutrophied ponds can contribute to aquatic biodiversity. A combination of regular draining of ponds with efforts to keep ponds free of fish seems to be highly beneficial for the biodiversity of many groups of aquatic organisms at local and regional scales. Regular draining combined with a stocking of fish at low biomass is also preferable to infrequent draining and lack of fish stock control. These insights are essential for the development of conservation programs that aim long-term maintenance of regional biodiversity in pond areas across Europe. PMID:23951328

  17. How to maximally support local and regional biodiversity in applied conservation? Insights from pond management.

    PubMed

    Lemmens, Pieter; Mergeay, Joachim; De Bie, Tom; Van Wichelen, Jeroen; De Meester, Luc; Declerck, Steven A J

    2013-01-01

    Biodiversity and nature values in anthropogenic landscapes often depend on land use practices and management. Evaluations of the association between management and biodiversity remain, however, comparatively scarce, especially in aquatic systems. Furthermore, studies also tend to focus on a limited set of organism groups at the local scale, whereas a multi-group approach at the landscape scale is to be preferred. This study aims to investigate the effect of pond management on the diversity of multiple aquatic organism groups (e.g. phytoplankton, zooplankton, several groups of macro-invertebrates, submerged and emergent macrophytes) at local and regional spatial scales. For this purpose, we performed a field study of 39 shallow man-made ponds representing five different management types. Our results indicate that fish stock management and periodic pond drainage are crucial drivers of pond biodiversity. Furthermore, this study provides insight in how the management of eutrophied ponds can contribute to aquatic biodiversity. A combination of regular draining of ponds with efforts to keep ponds free of fish seems to be highly beneficial for the biodiversity of many groups of aquatic organisms at local and regional scales. Regular draining combined with a stocking of fish at low biomass is also preferable to infrequent draining and lack of fish stock control. These insights are essential for the development of conservation programs that aim long-term maintenance of regional biodiversity in pond areas across Europe.

  18. A comparison of model-based and hyperbolic localization techniques as applied to marine mammal calls

    NASA Astrophysics Data System (ADS)

    Tiemann, Christopher O.; Porter, Michael B.

    2003-10-01

    A common technique for the passive acoustic localization of singing marine mammals is that of hyperbolic fixing. This technique assumes straight-line, constant wave speed acoustic propagation to associate travel time with range, but in some geometries, these assumptions can lead to localization errors. A new localization algorithm based on acoustic propagation models can account for waveguide and multipath effects, and it has successfully been tested against real acoustic data from three different environments (Hawaii, California, and Bahamas) and three different species (humpback, blue, and sperm whales). Accuracy of the model-based approach has been difficult to verify given the absence of concurrent visual and acoustic observations of the same animal. However, the model-based algorithm was recently exercised against a controlled source of known position broadcasting recorded whale sounds, and location estimates were then compared to hyperbolic techniques and true source position. In geometries where direct acoustic paths exist, both model-based and hyperbolic techniques perform equally well. However, in geometries where bathymetric and refractive effects are important, such as at long range, the model-based approach shows improved accuracy.

  19. Effect of ophthalmic preservatives on serum concentration and local irritation of ocularly applied insulin.

    PubMed

    Sasaki, H; Tei, C; Nishida, K; Nakamura, J

    1995-01-01

    We previously compared hypoglycemic responses after the instillation of insulin formulations. A hypoglycemic response was actually observed after an instillation of insulin with ophthalmic preservatives. In the present study, in order to evaluate the usefulness of insulin formulation containing ophthalmic preservatives, a serum concentration of insulin and an irritation to the eye were investigated after instillation of the insulin formulation in albino rabbits. The ophthalmic preservatives used were benzalkonium chloride, paraben, 2-phenylethanol, benzyl alcohol and sorbic acid. As a result, ophthalmic preservatives, especially benzalkonium chloride and paraben, increased the serum concentration of insulin. The insulin concentration showed a significant correlation with the hypoglycemic response reported previously. This result indicates that ophthalmic preservatives increase the absorption of ocularly applied insulin, and the absorbed insulin decreases serum glucose concentration. The insulin formulation with preservatives showed little irritation on rabbit eyes according to blinking measurements. These results indicate that ophthalmic preservatives are useful for the systemic delivery of ocularly applied insulin.

  20. Comparative Clustering of Plantar Pressure Distributions in Diabetics with Polyneuropathy May Be Applied to Reveal Inappropriate Biomechanical Stress.

    PubMed

    Niemann, Uli; Spiliopoulou, Myra; Szczepanski, Thorsten; Samland, Fred; Grützner, Jens; Senk, Dominik; Ming, Antao; Kellersmann, Juliane; Malanowski, Jan; Klose, Silke; Mertens, Peter R

    2016-01-01

    In diabetic patients, excessive peak plantar pressure has been identified as major risk factor for ulceration. Analyzing plantar pressure distributions potentially improves the identification of patients with a high risk for foot ulceration development. The goal of this study was to classify regional plantar pressure distributions. By means of a sensor-equipped insole, pressure recordings of healthy controls (n = 18) and diabetics with severe polyneuropathy (n = 25) were captured across eight foot regions. The study involved a controlled experimental protocol with multiple sessions, where a session contained several cycles of pressure exposure. Clustering was used to identify subgroups of study participants that are characterized by similar pressure distributions. For both analyzed groups, the number of clusters to best describe the pressure profiles was four. When both groups were combined, analysis again led to four distinct clusters. While three clusters did not separate between healthy and diabetic volunteers the fourth cluster was only represented by diabetics. Here the pressure distribution pattern is characterized by a focal point of pressure application on the forefoot and low pressure on the lateral region. Our data suggest that pressure clustering is a feasible means to identify inappropriate biomechanical plantar stress.

  1. Comparative Clustering of Plantar Pressure Distributions in Diabetics with Polyneuropathy May Be Applied to Reveal Inappropriate Biomechanical Stress

    PubMed Central

    Niemann, Uli; Spiliopoulou, Myra; Szczepanski, Thorsten; Samland, Fred; Grützner, Jens; Senk, Dominik; Ming, Antao; Kellersmann, Juliane; Malanowski, Jan; Klose, Silke; Mertens, Peter R.

    2016-01-01

    In diabetic patients, excessive peak plantar pressure has been identified as major risk factor for ulceration. Analyzing plantar pressure distributions potentially improves the identification of patients with a high risk for foot ulceration development. The goal of this study was to classify regional plantar pressure distributions. By means of a sensor-equipped insole, pressure recordings of healthy controls (n = 18) and diabetics with severe polyneuropathy (n = 25) were captured across eight foot regions. The study involved a controlled experimental protocol with multiple sessions, where a session contained several cycles of pressure exposure. Clustering was used to identify subgroups of study participants that are characterized by similar pressure distributions. For both analyzed groups, the number of clusters to best describe the pressure profiles was four. When both groups were combined, analysis again led to four distinct clusters. While three clusters did not separate between healthy and diabetic volunteers the fourth cluster was only represented by diabetics. Here the pressure distribution pattern is characterized by a focal point of pressure application on the forefoot and low pressure on the lateral region. Our data suggest that pressure clustering is a feasible means to identify inappropriate biomechanical plantar stress. PMID:27529421

  2. Differential localization of LGR5 and Nanog in clusters of colon cancer stem cells.

    PubMed

    Amsterdam, Abraham; Raanan, Calanit; Schreiber, Letizia; Freyhan, Ora; Fabrikant, Yakov; Melzer, Ehud; Givol, David

    2013-05-01

    One paradigm of cancer development claims that cancer emerges at the niche of tissue stem cells and these cells continue to proliferate in the tumor as cancer stem cells. LGR5, a membrane receptor, was recently found to be a marker of normal colon stem cells in colon polyps and is also expressed in colon cancer stem cells. Nanog, an embryonic stem cell nuclear factor, is expressed in several embryonic tissues, but Nanog expression is not well documented in cancerous stem cells. Our aim was to examine whether both LGR5 and Nanog are expressed in the same clusters of colon stem cells or cancer stem cells, using immunocytochemistry with specific antibodies to each antigen. We analyzed this aspect using paraffin embedded tumor tissue sections obtained from 18 polyps and 36 colon cancer specimens at stages I-IV. Antibodies to LGR5 revealed membrane and cytoplasm immunostaining of scattered labeled cells in normal crypts, with no labeling of Nanog. However, in close proximity to the tumors, staining to LGR5 was much more intensive in the crypts, including that of the epithelial cells. In cancer tissue, positive LGR5 clusters of stem cells were observed mainly in poorly differentiated tumors and in only a few scattered cells in the highly differentiated tumors. In contrast, antibodies to Nanog mainly stained the growing edges of carcinoma cells, leaving the poorly differentiated tumor cells unlabeled, including the clustered stem cells that could be detected even by direct morphological examination. In polyp tissues, scattered labeled cells were immunostained with antibodies to Nanog and to a much lesser extent with antibodies to LGR5. We conclude that expression of LGR5 is probably specific to stem cells of poorly differentiated tumors, whereas Nanog is mainly expressed at the edges of highly differentiated tumors. However, some of the cell layers adjacent to the carcinoma cell layers that still remained undifferentiated, expressed mainly Nanog with only a few cells

  3. Fungi and bacteria inventory on soybean (Glycine max (L.) merill) planting media applied by local microorganisms

    NASA Astrophysics Data System (ADS)

    Akhsan, Ni'matuljannah; Vionita

    2017-02-01

    An experiment aimed to determine the effect of application of several types of local microorganisms (MOL) and the number of doses to the development of fungi and bacteria on soybean planting media, have been conducted in Samarinda for 3 (three) months. Factorial experiment arranged in a completely randomized design and repeated three times, was used in this experiment. The first factor was the type of MOL consisted of cow dung (m1), snails (m2), banana peel (m3) and bamboo roots (m4), and the second factor was the dose MOL zero mL (d0), 100 mL (d1), 200 mL (d2), 300 mL (d3), 400 mL (d4) analyzed with Anova and Least Significance Difference (LSD) at 5%. Fungi and bacteria contained in the local microorganisms (cow dung, snails, banana peel and bamboo root) are: fungus Aspergillus sp, Penicillium sp., Trichoderma sp., cellulotic and lignolitic bacteria. An increase in the type and amount of fungus is happened for some genus. The dominant bacteria in the planting medium is a gram-negative bacteria. Cow dung seemed the best source at the dosages level of 400 ml.

  4. Geographic and topographic determinants of local FMD transmission applied to the 2001 UK FMD epidemic.

    PubMed

    Bessell, Paul R; Shaw, Darren J; Savill, Nicholas J; Woolhouse, Mark E J

    2008-10-03

    Models of Foot and Mouth Disease (FMD) transmission have assumed a homogeneous landscape across which Euclidean distance is a suitable measure of the spatial dependency of transmission. This paper investigated features of the landscape and their impact on transmission during the period of predominantly local spread which followed the implementation of the national movement ban during the 2001 UK FMD epidemic. In this study 113 farms diagnosed with FMD which had a known source of infection within 3 km (cases) were matched to 188 control farms which were either uninfected or infected at a later timepoint. Cases were matched to controls by Euclidean distance to the source of infection and farm size. Intervening geographical features and connectivity between the source of infection and case and controls were compared. Road distance between holdings, access to holdings, presence of forest, elevation change between holdings and the presence of intervening roads had no impact on the risk of local FMD transmission (p > 0.2). However the presence of linear features in the form of rivers and railways acted as barriers to FMD transmission (odds ratio = 0.507, 95% CIs = 0.297,0.887, p = 0.018). This paper demonstrated that although FMD spread can generally be modelled using Euclidean distance and numbers of animals on susceptible holdings, the presence of rivers and railways has an additional protective effect reducing the probability of transmission between holdings.

  5. Least squares collocation applied to local gravimetric solutions from satellite gravity gradiometry data

    NASA Technical Reports Server (NTRS)

    Robbins, J. W.

    1985-01-01

    An autonomous spaceborne gravity gradiometer mission is being considered as a post Geopotential Research Mission project. The introduction of satellite diometry data to geodesy is expected to improve solid earth gravity models. The possibility of utilizing gradiometer data for the determination of pertinent gravimetric quantities on a local basis is explored. The analytical technique of least squares collocation is investigated for its usefulness in local solutions of this type. It is assumed, in the error analysis, that the vertical gravity gradient component of the gradient tensor is used as the raw data signal from which the corresponding reference gradients are removed to create the centered observations required in the collocation solution. The reference gradients are computed from a high degree and order geopotential model. The solution can be made in terms of mean or point gravity anomalies, height anomalies, or other useful gravimetric quantities depending on the choice of covariance types. Selected for this study were 30 x 30 foot mean gravity and height anomalies. Existing software and new software are utilized to implement the collocation technique. It was determined that satellite gradiometry data at an altitude of 200 km can be used successfully for the determination of 30 x 30 foot mean gravity anomalies to an accuracy of 9.2 mgal from this algorithm. It is shown that the resulting accuracy estimates are sensitive to gravity model coefficient uncertainties, data reduction assumptions and satellite mission parameters.

  6. An improved equivalent magnetization current method applied to the design of local breast gradient coils

    NASA Astrophysics Data System (ADS)

    Lopez, Hector Sanchez; Poole, Michael; Crozier, Stuart

    2009-07-01

    Magnetic resonance imaging (MRI) is an important tool in the diagnosis of breast cancer. Increased gradient strengths and slew rates assist in terms of the potential to image with increased spatial and/or temporal resolution. Strong gradients also facilitate diffusion studies; one well-known method of increasing gradient strength is to design local gradient coils, those with reduced diameter where the gradient conductors are closer to the region of interest. In the case of breast imaging, this necessitates the use of coil geometries that lack the symmetry (e.g. cylindrical) required by some standard coil design techniques. Therefore a symmetry-free, inverse boundary element method (BEM) was employed to design a set of local breast gradient coils which would allow simultaneous imaging of both breasts. This BEM is a modified version of a previously reported equivalent magnetisation current method that now incorporates a piecewise-linear magnetisation rather than piecewise-constant. It is demonstrated that coil geometries more closely encompassing the sample shape, hence possessing wire windings located close the sample, produce superior coil performances. The use of two regions of interest instead one that covers the two samples produces superior high performance breast gradient coils. Additionally, it was demonstrated that this inverse BEM produced standard cylindrical coils with comparable properties and that the method is robust when challenged with difficult coil design problems in two other examples.

  7. Applying Gaussian mixture models to the Na-O plane to separate multiple populations in globular clusters

    NASA Astrophysics Data System (ADS)

    Boberg, Owen M.; Friel, Eileen D.; Vesperini, Enrico

    2016-06-01

    We present the results of an analysis using Gaussian mixture models (GMM) to separate multiple populations in Milky Way globular clusters based on the Na and O abundances of their members. Recent studies have shown that the method used to separate the populations in globular clusters (e.g. photometry, molecular band strengths, light element abundances) can result in different fractions of primordial and second generation stars. These fractions have important implications on the mass lost by globular clusters during their evolution, and the mechanism responsible for creating the second generation. For many previous studies, the first generation (FG) stars, with primordial Na and O, were classified as such by falling below a maximum [Na/Fe] abundance based on the estimated [Na/Fe] of the Milky Way field population most similar to a given cluster. Stars that were above this [Na/Fe] threshold were classified as second generation (SG) stars, representing the Na enhanced and O depleted population in the cluster. The method we present here is based on separating these populations in the [Na/Fe] vs [O/Fe] plane by constructing a multi-component, and multi-dimensional, GMM. The dataset provided by Carretta et al. 2009 provides a homogeneous sample of [Na/Fe] and [O/Fe] abundances in ~1,000 stars in southern globular clusters. Using all of the stars available in this sample, we created a general GMM that was subsequently used to classify the stars in individual clusters as FG or SG. To perform this classification, the stars in each cluster are assigned a probability of belonging to each of the Gaussian components in the GMM calculated from the entire Carretta sample. Based on these probabilities, we can assign a given star to the FG or SG. Here we present how the fractions of FG and SG stars present in a given globular cluster, as calculated by our GMM, compare to those determined from a single [Na/Fe] threshold. We will also characterize how the fractions of FG and SG stars

  8. Effect of glycerol on local and systemic carcinogenicity of topically applied tobacco condensate.

    PubMed Central

    Wilson, J.; Clapp, M. J.; Conning, D. M.

    1978-01-01

    When glycerol was added to tobacco smoke condensate in acetone solvent, the topical carcinogenicity and the ability to produce epithelial hyperplasia in mice was reduced. Two doses of condensate were applied, combined with 2 concentrations of added glycerol. Age-standardized results show that glycerol reduced the incidence of tumours and malignant tumours and of hyperplasia in animals not developing skin tumours. The relative incidences of malignant tumours, benign tumours, hyperplasia and unaffected skin suggest that there is a sequential relationship (i.e. normal skin to hyperplasia to benign neoplasia to malignant neoplasia) which is impeded by glycerol. There was no systemic effect attributable to the condensate. PMID:698039

  9. Three-dimensional super-resolution and localization of dense clusters of single molecules

    PubMed Central

    Barsic, Anthony; Grover, Ginni; Piestun, Rafael

    2014-01-01

    When a single molecule is detected in a wide-field microscope, the image approximates the point spread function of the system. However, as the distribution of molecules becomes denser and their images begin to overlap, existing solutions to determine the number of molecules present and their precise three-dimensional locations can tolerate little to no overlap. We propose a localization scheme that can identify several overlapping molecule images while maintaining high localization precision. A solution to this problem involving matched optical and digital techniques, as here proposed, can substantially increase the allowable labeling density and accelerate the data collection time of single-molecule localization microscopy by more than one order of magnitude. PMID:24953078

  10. A local space–time kriging approach applied to a national outpatient malaria data set

    PubMed Central

    Gething, P.W.; Atkinson, P.M.; Noor, A.M.; Gikandi, P.W.; Hay, S.I.; Nixon, M.S.

    2007-01-01

    Increases in the availability of reliable health data are widely recognised as essential for efforts to strengthen health-care systems in resource-poor settings worldwide. Effective health-system planning requires comprehensive and up-to-date information on a range of health metrics and this requirement is generally addressed by a Health Management Information System (HMIS) that coordinates the routine collection of data at individual health facilities and their compilation into national databases. In many resource-poor settings, these systems are inadequate and national databases often contain only a small proportion of the expected records. In this paper, we take an important health metric in Kenya (the proportion of outpatient treatments for malaria (MP)) from the national HMIS database and predict the values of MP at facilities where monthly records are missing. The available MP data were densely distributed across a spatiotemporal domain and displayed second-order heterogeneity. We used three different kriging methodologies to make cross-validation predictions of MP in order to test the effect on prediction accuracy of (a) the extension of a spatial-only to a space–time prediction approach, and (b) the replacement of a globally stationary with a locally varying random function model. Space–time kriging was found to produce predictions with 98.4% less mean bias and 14.8% smaller mean imprecision than conventional spatial-only kriging. A modification of space–time kriging that allowed space–time variograms to be recalculated for every prediction location within a spatially local neighbourhood resulted in a larger decrease in mean imprecision over ordinary kriging (18.3%) although the mean bias was reduced less (87.5%). PMID:19424510

  11. Global and local reactivity indexes applied to understand the chemistry of graphene oxide and doped graphene.

    PubMed

    Cortés Arriagada, Diego

    2013-02-01

    At the density functional theory level, the electronic reactivity of oxidized and doped (with N, B, and P) graphene (G) has been analyzed. Molecular hardness and electrophilicity were used as global reactivity descriptors, while those at the local level, Fukui functions, Mulliken charges and molecular electrostatic potential were used in the order to characterize the intramolecular and intermolecular reactivity. These descriptors show that in GO, the global and local reactivity of the basal plane is improved mainly by hydroxyl groups, which improve besides the physisorption of small molecules, while, the active carbon atoms around the functional group would allow enhancement of the consecutively chemisorption. Furthermore, epoxide, carbonyl and carboxyl groups allow mainly enhancement of intermolecular non-covalent interactions. On the other hand, doping with N and B atoms increases the electrophilic character and the reactivity in the bulk. Specifically, in N-doped G, N and around carbon atoms would be able to serve as active sites of detection by frontier-controlled processes, explaining the improvement in electrochemical sensing; in addition, electron-deficient carbon atoms around N enhance the physisorption. Respecting the B-doped G, dopant and carbon atoms adjacent to B act as donor sites, suggesting that adsorption of cations on B-doped G is a frontier-controlled process; moreover, positively-charged B atoms enhance charge-controlled interactions with polarized molecules, and consecutively, in a frontier-controlled step, chemisorption is possible. Finally, P-doping increases the electrophilic reactivity in the bulk; also, P atoms enhance the physisorption of chemical species with negatively-charged centers or lone-pair electrons, and consecutively, chemisorption on P is possible.

  12. Acoustic sources of opportunity in the marine environment - Applied to source localization and ocean sensing

    NASA Astrophysics Data System (ADS)

    Verlinden, Christopher M.

    Controlled acoustic sources have typically been used for imaging the ocean. These sources can either be used to locate objects or characterize the ocean environment. The processing involves signal extraction in the presence of ambient noise, with shipping being a major component of the latter. With the advent of the Automatic Identification System (AIS) which provides accurate locations of all large commercial vessels, these major noise sources can be converted from nuisance to beacons or sources of opportunity for the purpose of studying the ocean. The source localization method presented here is similar to traditional matched field processing, but differs in that libraries of data-derived measured replicas are used in place of modeled replicas. In order to account for differing source spectra between library and target vessels, cross-correlation functions are compared instead of comparing acoustic signals directly. The library of measured cross-correlation function replicas is extrapolated using waveguide invariant theory to fill gaps between ship tracks, fully populating the search grid with estimated replicas allowing for continuous tracking. In addition to source localization, two ocean sensing techniques are discussed in this dissertation. The feasibility of estimating ocean sound speed and temperature structure, using ship noise across a drifting volumetric array of hydrophones suspended beneath buoys, in a shallow water marine environment is investigated. Using the attenuation of acoustic energy along eigenray paths to invert for ocean properties such as temperature, salinity, and pH is also explored. In each of these cases, the theory is developed, tested using numerical simulations, and validated with data from acoustic field experiments.

  13. Sustaining a quality improvement culture in local health departments applying for accreditation.

    PubMed

    Verma, Pooja; Moran, John W

    2014-01-01

    This article focuses on local health departments (LHDs) that are advanced in accreditation and quality improvement (QI) efforts and the barriers and facilitators associated with sustaining improvements and building an organizational culture of QI. To understand the barriers and facilitators associated with building and sustaining progress toward a QI culture in LHDs. Quantitative data from a self-reporting survey and qualitative data from telephone interviews. Twenty-two LHDs across the United States responded to the survey. Ten of the 22 LHD respondents participated in telephone interviews. QI lead staff at LHDs that are advanced in accreditation preparation and QI. Self-reported LHD survey ratings against indicators for a QI culture, and the identified barriers and facilitators around sustaining QI initiatives. Of the 6 domains of a QI culture measured in the survey, the percentages of respondents that scored themselves highly to at least 1 indicator in each domain are as follows: leadership commitment (100%); employee empowerment (100%); teamwork and collaboration (100%); continuous process improvement (86%); customer focus (72%); and QI infrastructure (64%). Qualitative data from 10 telephone interviews revealed that key barriers to sustaining progress around QI included staff turnover, budget cuts, and major crises or events that arise as priority. Key facilitators included leadership commitment, accreditation, and dedication of resources and staff time to QI. When engaging in QI, LHDs should consider investing efforts in gaining leadership support and dedicating staff time early in the QI journey to ensure that QI efforts and initiatives are sustained. Local health departments interested in developing a QI culture should also consider pursuing accreditation, as it provides a structured framework for continuous improvement. They should also actively develop QI knowledge and skills among all staff members to minimize the negative impact of staff turnover.

  14. Clinical parameters of the local anesthetic effects of bupivacaine applied with and without a vasoconstrictor in oral implantology.

    PubMed

    Duka, Milos; Lazić, Zoran; Stamatović, Novak; Tatić, Zoran; Bubalo, Marija; Veljović, Milić

    2007-09-01

    Bupivacaine (Marcaine), homologue of mepivacaine, chemically related to lidocaine, is used as a local anesthetic for local infiltration, peripheral nerve block, retrobulbar block, symphathetic block, and caudal and epidural anesthesia. The aim of this investigation was to determine and to compare clinical parameters of the local anesthetic effects of bupivacaine applied with and without a vasoconstrictor. This investigation included a total of 30 randomly selected patients, who ranged in age from 30-60 years, with partial or total anodontia in the molar region of the mandible. These patients with total or partial edentulous molar part of the mandible, scheduled for dental implantation placement, were asked to participate in the study. In the first phase of the investigation, the patients were subjected to local anesthesia with 3.5 cm3 of 0.5% bupivacaine with a vasoconstrictor (adrenalin, 1: 200,000) in the right side of the mandible. After administering local anesthesia, the placement of blade, cylindrical, transdental (B.C.T.) implants was performed. In the second stage of the investigation, in 7-10 days period after the first oral surgery, the patients were subjected to local anesthesia with 3.5 cm3 of 0.5% bupivacaine, but without a vasoconstrictor, in the left side of the mandible. After administering local anesthesia, the placement of B.C.T. implants was performed. During the performance of both oral surgery procedures, the following clinical parameters of the local anesthetic effects were monitored: latent period, duration and the potency of anesthesia, and the evaluation of the postoperative pain level. The latent period under local anesthesia with 3.5 cm3 of 0.5% bupivacaine and vasoconstrictor was statistically significantly shorter than without vasoconstrictor. The duration of local anesthesia was longer without vasoconstrictor. There was no difference in the potency of anesthesia with or without a vasoconstrictor, while the lowest level of postoperative

  15. Clustering of local group distances: Publication bias or correlated measurements? II. M31 and beyond

    SciTech Connect

    De Grijs, Richard; Bono, Giuseppe

    2014-07-01

    The accuracy of extragalactic distance measurements ultimately depends on robust, high-precision determinations of the distances to the galaxies in the local volume. Following our detailed study addressing possible publication bias in the published distance determinations to the Large Magellanic Cloud (LMC), here we extend our distance range of interest to include published distance moduli to M31 and M33, as well as to a number of their well-known dwarf galaxy companions. We aim at reaching consensus on the best, most homogeneous, and internally most consistent set of Local Group distance moduli to adopt for future, more general use based on the largest set of distance determinations to individual Local Group galaxies available to date. Based on a careful, statistically weighted combination of the main stellar population tracers (Cepheids, RR Lyrae variables, and the magnitude of the tip of the red-giant branch), we derive a recommended distance modulus to M31 of (m−M){sub 0}{sup M31}=24.46±0.10 mag—adopting as our calibration an LMC distance modulus of (m−M){sub 0}{sup LMC}=18.50 mag—and a fully internally consistent set of benchmark distances to key galaxies in the local volume, enabling us to establish a robust and unbiased, near-field extragalactic distance ladder.

  16. Clustering of Local Group Distances: Publication Bias or Correlated Measurements? II. M31 and Beyond

    NASA Astrophysics Data System (ADS)

    de Grijs, Richard; Bono, Giuseppe

    2014-07-01

    The accuracy of extragalactic distance measurements ultimately depends on robust, high-precision determinations of the distances to the galaxies in the local volume. Following our detailed study addressing possible publication bias in the published distance determinations to the Large Magellanic Cloud (LMC), here we extend our distance range of interest to include published distance moduli to M31 and M33, as well as to a number of their well-known dwarf galaxy companions. We aim at reaching consensus on the best, most homogeneous, and internally most consistent set of Local Group distance moduli to adopt for future, more general use based on the largest set of distance determinations to individual Local Group galaxies available to date. Based on a careful, statistically weighted combination of the main stellar population tracers (Cepheids, RR Lyrae variables, and the magnitude of the tip of the red-giant branch), we derive a recommended distance modulus to M31 of (m-M)_0^M31 = 24.46 +/- 0.10 mag—adopting as our calibration an LMC distance modulus of (m-M)_0^LMC = 18.50 mag—and a fully internally consistent set of benchmark distances to key galaxies in the local volume, enabling us to establish a robust and unbiased, near-field extragalactic distance ladder.

  17. A hybrid clustering approach for multivariate time series - A case study applied to failure analysis in a gas turbine.

    PubMed

    Fontes, Cristiano Hora; Budman, Hector

    2017-09-16

    A clustering problem involving multivariate time series (MTS) requires the selection of similarity metrics. This paper shows the limitations of the PCA similarity factor (SPCA) as a single metric in nonlinear problems where there are differences in magnitude of the same process variables due to expected changes in operation conditions. A novel method for clustering MTS based on a combination between SPCA and the average-based Euclidean distance (AED) within a fuzzy clustering approach is proposed. Case studies involving either simulated or real industrial data collected from a large scale gas turbine are used to illustrate that the hybrid approach enhances the ability to recognize normal and fault operating patterns. This paper also proposes an oversampling procedure to create synthetic multivariate time series that can be useful in commonly occurring situations involving unbalanced data sets. Copyright © 2017 ISA. Published by Elsevier Ltd. All rights reserved.

  18. TAP score: torsion angle propensity normalization applied to local protein structure evaluation

    PubMed Central

    Tosatto, Silvio CE; Battistutta, Roberto

    2007-01-01

    Background Experimentally determined protein structures may contain errors and require validation. Conformational criteria based on the Ramachandran plot are mainly used to distinguish between distorted and adequately refined models. While the readily available criteria are sufficient to detect totally wrong structures, establishing the more subtle differences between plausible structures remains more challenging. Results A new criterion, called TAP score, measuring local sequence to structure fitness based on torsion angle propensities normalized against the global minimum and maximum is introduced. It is shown to be more accurate than previous methods at estimating the validity of a protein model in terms of commonly used experimental quality parameters on two test sets representing the full PDB database and a subset of obsolete PDB structures. Highly selective TAP thresholds are derived to recognize over 90% of the top experimental structures in the absence of experimental information. Both a web server and an executable version of the TAP score are available at . Conclusion A novel procedure for energy normalization (TAP) has significantly improved the possibility to recognize the best experimental structures. It will allow the user to more reliably isolate problematic structures in the context of automated experimental structure determination. PMID:17504537

  19. Applying a nutribusiness approach to increase animal source food consumption in local communities.

    PubMed

    Maretzki, Audrey N; Mills, Edward W

    2003-11-01

    Animal source foods (ASF) in the diets of schoolchildren are beneficial for supporting optimal physical and cognitive development. Nevertheless, behavioral change and economic development are needed to increase and sustain adequate meat product consumption by schoolchildren in developing countries. A NutriBusiness enterprise may be one way for local communities to promote economic development while increasing the availability of meat for children. This work evaluates the feasibility of a NutriBusiness enterprise involving the production of rabbits and the manufacture of solar dried snack food. Some rabbits would be kept for home use, whereas others would be used in the manufacture of a rabbit-sweet potato dried snack food that could be fed to children or sold for income. The NutriBusiness enterprise would be composed of participants from the community contributing to a cooperative effort for setting up a manufacturing facility and organizing production, manufacturing and marketing functions. A unit operation for rabbit-sweet potato Chiparoos, based on full-capacity operation of a single solar drier would involve up to 110 shareholder families, each producing 240 rabbits/y with 120 used at home and 120 sold for Chiparoos manufacture. Participation in the enterprise would increase the availability to children of iron, zinc and vitamin B-12, and other nutrients, and provide approximately 350 dollars/y additional income for the family.

  20. Selective and localized radiofrequency heating of skin and fat by controlling surface distributions of the applied voltage: analytical study

    NASA Astrophysics Data System (ADS)

    Jiménez-Lozano, Joel; Vacas-Jacques, Paulino; Anderson, R. Rox; Franco, Walfre

    2012-11-01

    At low frequencies (hundreds of kHz to a few MHz), local energy absorption is proportional to the conductivity of tissue and the intensity of the internal electric field. At 1 MHz, the electric conductivity ratio between skin and fat is approximately 10; hence, skin would heat more provided the intensity of the electric field is similar in both tissues. It follows that selective and localized heat deposition is only feasible by varying electric fields locally. In this study, we vary local intensities of the internal electric field in skin, fat and muscle by altering its direction through modifying surface distributions of the applied voltage. In addition, we assess the long-term effects of these variations on tissue thermal transport. To this end, analytical solutions of the electric and bioheat equations were obtained using a regular perturbation method. For voltage distributions given by second- and eight-degree functions, the power absorption in fat is much greater than in skin by the electrode center while the opposite is true by the electrode edge. For a sinusoidal function, the absorption in fat varies laterally from greater to lower than in skin, and then this trend repeats from the center to the edge of the electrode. Consequently, zones of thermal confinement selectively develop in the fat layer. Generalizing these functions by parametrization, it is shown that radiofrequency (RF) heating of layered tissues can be selective and precisely localized by controlling the spatial decay, extent and repetition of the surface distribution of the applied voltage. The clinical relevance of our study is to provide a simple, non-invasive method to spatially control the heat deposition in layered tissues. By knowing and controlling the internal electric field, different therapeutic strategies can be developed and implemented.

  1. HYPODD Relocations and Stress Tensor Inversion Analyses of Local Earthquake Clusters in the Sea of Marmara

    NASA Astrophysics Data System (ADS)

    Korkusuz Öztürk, Yasemin; Meral Özel, Nurcan

    2016-04-01

    Extensional focal mechanism solutions are mostly observed even in the Central Marmara by this comprehensive research although the main Marmara Fault that is the western branch of the NAF, is dominated by a right lateral strike-slip regime. Marmara Region, a seismically very active area, is located at the western section of the North Anatolian Fault Zone (NAFZ). The 1912 Mürefte and 1999 Izmit earthquakes are the last devastating events of the western and eastern sections of this region, respectively. The region between the locations of these earthquakes, is prone to a large earthquake. Therefore, the analysis of the Sea of Marmara is significant. The main objective of this research is to determine earthquake hypocenters and focal mechanism solutions accurately, hence we obtain recent states of stresses for this region. Accordingly, this research aims to define branches of fault structures and its geometrical orientations in the Sea of Marmara. In this study, a cluster of events in the Central Marmara is analyzed using hypocenter program as a usual location technique. In addition, these events and other clustered events (Korkusuz Öztürk et al., 2015) are relocated using HYPODD relocation procedure. Even though NAF is mostly dominated by a right lateral strike slip fault, we found out many extensional source mechanisms. Also, from the comparison of relocation results of hypocenter and HYPODD programs, it is found out that most of the relocations have the same orientations and dipping angles of the segments of the main Marmara Fault are not clear. As a result, since we observe many normal faulting mechanisms in the Sea of Marmara, we expect to observe some deviations in orientations of vertical orientations of the fault segments comparing a dip-slip model. Therefore, this research will continue to clearly identify fault dip angles of main fault segments in Marmara Sea. Further, our sensitive relocation and stress analyses will make an important contribution to a

  2. The Ligurian Cluster for Marine Technologies (DLTM): matching local research and industrial needs on oceanographic data.

    NASA Astrophysics Data System (ADS)

    Stroobant, M.; Locritani, M.; Marini, D.; Sabbadini, L.; Carmisciano, C.; Manzella, G.; Magaldi, M.; Aliani, S.

    2012-04-01

    DLTM is the Ligurian Region (north Italy) cluster of Centre of Excellence (CoE) in waterborne technologies, that involves about 120 enterprises - of which, more than 100 SMEs -, the University of Genoa, all the main National Research Centres dealing with maritime and marine technologies established in Liguria (CNR, INGV, ENEA-UTMAR), the NATO Undersea Research Centre (NURC) and the Experimental Centre of the Italian Navy (CSSN), the Bank, the Port Authority and the Chamber of Commerce of the city of La Spezia. Following its mission, DLTM has recently established three Collaborative Research Laboratories focused on: 1. Computational Fluid dynamics (CFD_Lab) 2. High Performance Computing (HPC_Lab) 3. Monitoring and Analysis of Marine Ecosystems (MARE_Lab). The main role of them is to improve the relationships among the research centres and the enterprises, encouraging a systematic networking approach and sharing of knowledge, data, services, tools and human resources. Two of the key objectives of Lab_MARE are the establishment of: - an integrated system of observation and sea forecasting; - a Regional Marine Instrument Centre (RMIC) for oceanographic and metereological instruments (assembled using 'shared' tools and facilities). Besides, an important and innovative research project has been recently submitted to the Italian Ministry for Education, University and Research (MIUR). This project, in agreement with the European Directives (COM2009 (544)), is aimed to develop a Management Information System (MIS) for oceanographic and meteorological data in the Mediterranean Sea. The availability of adequate HPC inside DLTM is, of course, an important asset for achieving useful results; for example, the Regional Ocean Modeling System (ROMS) model is currently running on a high-resolution mesh on the cluster to simulate and reproduce the circulation within the Ligurian Sea. ROMS outputs will have broad and multidisciplinary impacts because ocean circulation affects the

  3. Clustering of Local Group Distances: Publication Bias or Correlated Measurements? V. Galactic Rotation Constants

    NASA Astrophysics Data System (ADS)

    de Grijs, Richard; Bono, Giuseppe

    2017-10-01

    As part of an extensive data mining effort, we have compiled a database of 162 Galactic rotation speed measurements at R 0 (the solar Galactocentric distance), {{{\\Theta }}}0. Published between 1927 and 2017 June, this represents the most comprehensive set of {{{\\Theta }}}0 values since the 1985 meta-analysis that led to the last revision of the International Astronomical Union’s recommended Galactic rotation constants. Although we do not find any compelling evidence for the presence of “publication bias” in recent decades, we find clear differences among the {{{\\Theta }}}0 values and the {{{\\Theta }}}0/{R}0 ratios resulting from the use of different tracer populations. Specifically, young tracers (including OB and supergiant stars, masers, Cepheid variables, H ii regions, and young open clusters), as well as kinematic measurements of Sgr A* near the Galactic Center, imply a significantly larger Galactic rotation speed at the solar circle and a higher {{{\\Theta }}}0/{R}0 ratio (i.e., {{{\\Theta }}}0=247+/- 3 km s‑1 and {{{\\Theta }}}0/{R}0=29.81+/- 0.32 km s‑1 kpc‑1 statistical uncertainties only) than any of the tracers dominating the Galaxy’s mass budget (i.e., field stars and the H i/CO distributions). Using the latter to be most representative of the bulk of the Galaxy’s matter distribution, we arrive at an updated set of Galactic rotation constants,

  4. Similarity-transformed perturbation theory on top of truncated local coupled cluster solutions: Theory and applications to intermolecular interactions

    SciTech Connect

    Azar, Richard Julian Head-Gordon, Martin

    2015-05-28

    Your correspondents develop and apply fully nonorthogonal, local-reference perturbation theories describing non-covalent interactions. Our formulations are based on a Löwdin partitioning of the similarity-transformed Hamiltonian into a zeroth-order intramonomer piece (taking local CCSD solutions as its zeroth-order eigenfunction) plus a first-order piece coupling the fragments. If considerations are limited to a single molecule, the proposed intermolecular similarity-transformed perturbation theory represents a frozen-orbital variant of the “(2)”-type theories shown to be competitive with CCSD(T) and of similar cost if all terms are retained. Different restrictions on the zeroth- and first-order amplitudes are explored in the context of large-computation tractability and elucidation of non-local effects in the space of singles and doubles. To accurately approximate CCSD intermolecular interaction energies, a quadratically growing number of variables must be included at zeroth-order.

  5. Formation of Si clusters in AlGaN: A study of local structure

    SciTech Connect

    Somogyi, A.; Martinez-Criado, G.; Homs, A.; Hernandez-Fenollosa, M. A.; Vantelon, D.; Ambacher, O.

    2007-04-30

    In this study, the authors report on the application of synchrotron radiation x-ray microprobe to the study of Si impurities in plasma-induced molecular beam epitaxy grown Al{sub 0.32}Ga{sub 0.68}N. Elemental maps obtained by {mu}-x-ray fluorescence spectrometry show inhomogeneous distributions of Si, Al, and Ga on the micron scale. X-ray absorption near-edge structure spectra taken at the Si and Al K edges provided information about their local chemical environment and revealed the change of the spectral features as depending on the position compared to the sample surface and on the concentration of Si.

  6. Continuous control of local magnetic moment by applied electric field in multiferroics Ba2CoGe2O7

    NASA Astrophysics Data System (ADS)

    Soda, Minoru; Hayashida, Shohei; Roessli, Bertrand; Mânsson, Martin; White, Jonathan S.; Matsumoto, Masashige; Shiina, Ryousuke; Masuda, Takatsugu

    2016-09-01

    Ba2CoGe2O7 exhibits a collinear-antiferromagnetic structure with the easy axis along <100 > directions and an antiferroelectric order with the polarization axis along the [001] direction. By applying the electric field the magnetic moment rotates from <100 > to [110] directions and, simultaneously, the antiferroelectric state changes to the ferroelectric state gradually. This magnetoelectric effect, i.e., continuous control of the local magnetic moment by the electric field, is quantitatively explained by the Hamiltonian including the dielectric energy.

  7. Analysis of the influence of the applied voltage and the scan speed in the atomic force microscopy local oxidation technique

    NASA Astrophysics Data System (ADS)

    Mendoza, C.; Plata, A.; Lizarazo, Z.; Chacón, C. A.

    2016-02-01

    The local nanolithography oxidation technique is implemented by using an atomic force microscope (AFM) for the fabrication of nanoscale patterning structures on a silicon substrate covered whit a thin film of silicon nitride. During the fabrication process, the microscope is operated on air and contact mode utilizing a silicon tip covered whit a hard Cobalt- Chromium coat. The dependence of the oxide growth with the applied voltage was investigated varying this parameter in a range of 1 to 10V to constant scanning speed; the influence of the writing speed in the dimensions of the oxide formed is also analysed varying the speed values between 0.1 to 1μm/s. Is found that the dimensions of lines depend of scanning speed and voltages applied.

  8. 34 CFR 222.3 - How does a local educational agency apply for assistance under section 8002 or 8003 of the Act?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 34 Education 1 2012-07-01 2012-07-01 false How does a local educational agency apply for assistance under section 8002 or 8003 of the Act? 222.3 Section 222.3 Education Regulations of the Offices of... IMPACT AID PROGRAMS General § 222.3 How does a local educational agency apply for assistance...

  9. Molecular (global) and atom-in-cluster (local) polarizabilities of medium-size gold nanoclusters: isomer structure effects

    NASA Astrophysics Data System (ADS)

    Rodríguez, Juan I.; Baltazar-Méndez, Maria I.; Autschbach, Jochen; Castillo-Alvarado, F. L.

    2013-06-01

    In this work, we extend our recent study [J.I. Rodríguez, J. Autschbach, F.L. Castillo-Alvarado, M.I. Baltazar-Méndez, J. Chem. Phys. 135, 034109 (2011)] to quantify the isomer structure effects on the atom-in-cluster polarizabilities of medium size gold clusters Au ( n = 6, 12, 20, 34, 54). For three isomers for each cluster size, a density functional perturbation theory calculation was performed to compute the cluster polarizability and the polarizability of each atom in the cluster using Bader's "quantum theory of atoms in molecules" formalism. The cluster polarizability tensor is expressed as a sum of the atom-in-cluster atomic tensors. We found that the strong quadratic correlation ( R 2 = 0.98) in the isotropic polarizability of atoms in the cluster and their distance to the cluster center of mass reported before holds independently of the cluster structure.

  10. Evidence for New Excess Electron Localization Sites in Na{sub {ital n}}F{sub {ital n}{minus}1 } Alkali-Halide Clusters

    SciTech Connect

    Durand, G.; Spiegelmann, F.; Labastie, P.; LHermite, J.; Poncharal, P.

    1997-07-01

    This Letter examines new types of localization sites for an excess electron in finite alkali-halide clusters resulting from defects on cuboidal structures, namely {open_quotes}edge states,{close_quotes} R center, and other surface defects. We present theoretical calculations on Na{sub n}F {sub n{minus}1} clusters with one excess electron. Comparisons with experimental results are presented for different cluster sizes (n=17 , 23, 28, and 29). Structures with edge or surface defects are relevant for n=23 , 28, and 29. {copyright} {ital 1997} {ital The American Physical Society}

  11. Local Arp2/3-dependent actin assembly modulates applied traction force during apCAM adhesion site maturation

    PubMed Central

    Buck, Kenneth B.; Schaefer, Andrew W.; Schoonderwoert, Vincent T.; Creamer, Matthew S.; Dufresne, Eric R.; Forscher, Paul

    2017-01-01

    Homophilic binding of immunoglobulin superfamily molecules such as the Aplysia cell adhesion molecule (apCAM) leads to actin filament assembly near nascent adhesion sites. Such actin assembly can generate significant localized forces that have not been characterized in the larger context of axon growth and guidance. We used apCAM-coated bead substrates applied to the surface of neuronal growth cones to characterize the development of forces evoked by varying stiffness of mechanical restraint. Unrestrained bead propulsion matched or exceeded rates of retrograde network flow and was dependent on Arp2/3 complex activity. Analysis of growth cone forces applied to beads at low stiffness of restraint revealed switching between two states: frictional coupling to retrograde flow and Arp2/3-dependent propulsion. Stiff mechanical restraint led to formation of an extensive actin cup matching the geometric profile of the bead target and forward growth cone translocation; pharmacological inhibition of the Arp2/3 complex or Rac attenuated F-actin assembly near bead binding sites, decreased the efficacy of growth responses, and blocked accumulation of signaling molecules associated with nascent adhesions. These studies introduce a new model for regulation of traction force in which local actin assembly forces buffer nascent adhesion sites from the mechanical effects of retrograde flow. PMID:27852899

  12. Existing Whole-House Solutions Case Study: Applying Best Practices to Florida Local Government Retrofit Programs - Central Florida

    SciTech Connect

    2014-03-01

    In some communities, local government and non-profit entities have funds to purchase and renovate distressed, foreclosed homes for resale in the affordable housing market. Numerous opportunities to improve whole house energy efficiency are inherent in these comprehensive renovations. BA-PIRC worked together in a multiyear field study making recommendations in individual homes, meanwhile compiling improvement costs, projected energy savings, practical challenges, and labor force factors surrounding common energy-related renovation measures. The field study, Phase 1 of this research, resulted in a set of best practices appropriate to the current labor pool and market conditions in central Florida to achieve projected annual energy savings of 15%-30% and higher. This case study describes Phase 2 of the work where researchers worked with a local government partner to implement and refine the "current best practices". A simulation study was conducted to characterize savings potential under three sets of conditions representing varying replacement needs for energy-related equipment and envelope components. The three scenarios apply readily to the general remodeling industry as for renovation of foreclosed homes for the affordable housing market. The new local government partner, the City of Melbourne, implemented the best practices in a community-scale renovation program that included ten homes in 2012.

  13. Projected Irrigation Requirement Under Climate Change in Korean Peninsula by Apply Global Hydrologic Model to Local Scale.

    NASA Astrophysics Data System (ADS)

    Yang, B.; Lee, D. K.

    2016-12-01

    Understanding spatial distribution of irrigation requirement is critically important for agricultural water management. However, many studies considering future agricultural water management in Korea assessed irrigation requirement on watershed or administrative district scale, but have not accounted the spatial distribution. Lumped hydrologic model has typically used in Korea for simulating watershed scale irrigation requirement, while distribution hydrologic model can simulate the spatial distribution grid by grid. To overcome this shortcoming, here we applied a grid base global hydrologic model (H08) into local scale to estimate spatial distribution under future irrigation requirement of Korean Peninsula. Korea is one of the world's most densely populated countries, with also high produce and demand of rice which requires higher soil moisture than other crops. Although, most of the precipitation concentrate in particular season and disagree with crop growth season. This precipitation character makes management of agricultural water which is approximately 60% of total water usage critical issue in Korea. Furthermore, under future climate change, the precipitation predicted to be more concentrated and necessary need change of future water management plan. In order to apply global hydrological model into local scale, we selected appropriate major crops under social and local climate condition in Korea to estimate cropping area and yield, and revised the cropping area map more accurately. As a result, future irrigation requirement estimation varies under each projection, however, slightly decreased in most case. The simulation reveals, evapotranspiration increase slightly while effective precipitation also increase to balance the irrigation requirement. This finding suggest practical guideline to decision makers for further agricultural water management plan including future development of water supply plan to resolve water scarcity.

  14. Fat-associated lymphoid clusters control local IgM secretion during pleural infection and lung inflammation

    PubMed Central

    Jackson-Jones, Lucy H.; Duncan, Sheelagh M.; Magalhaes, Marlène S.; Campbell, Sharon M.; Maizels, Rick M.; McSorley, Henry J.; Allen, Judith E.; Bénézech, Cécile

    2016-01-01

    Fat-associated lymphoid clusters (FALC) are inducible structures that support rapid innate-like B-cell immune responses in the serous cavities. Little is known about the physiological cues that activate FALCs in the pleural cavity and more generally the mechanisms controlling B-cell activation in FALCs. Here we show, using separate models of pleural nematode infection with Litomosoides sigmodontis and Altenaria alternata induced acute lung inflammation, that inflammation of the pleural cavity rapidly activates mediastinal and pericardial FALCs. IL-33 produced by FALC stroma is crucial for pleural B1-cell activation and local IgM secretion. However, B1 cells are not the direct target of IL-33, which instead requires IL-5 for activation. Moreover, lung inflammation leads to increased IL-5 production by type 2 cytokine-producing innate lymphoid cells (ILC2) in the FALC. These findings reveal a link between inflammation, IL-33 release by FALC stromal cells, ILC2 activation and pleural B-cell activation in FALCs, resulting in local and antigen-specific IgM production. PMID:27582256

  15. MicroRNA-Target Network Inference and Local Network Enrichment Analysis Identify Two microRNA Clusters with Distinct Functions in Head and Neck Squamous Cell Carcinoma.

    PubMed

    Sass, Steffen; Pitea, Adriana; Unger, Kristian; Hess, Julia; Mueller, Nikola S; Theis, Fabian J

    2015-12-18

    MicroRNAs represent ~22 nt long endogenous small RNA molecules that have been experimentally shown to regulate gene expression post-transcriptionally. One main interest in miRNA research is the investigation of their functional roles, which can typically be accomplished by identification of mi-/mRNA interactions and functional annotation of target gene sets. We here present a novel method "miRlastic", which infers miRNA-target interactions using transcriptomic data as well as prior knowledge and performs functional annotation of target genes by exploiting the local structure of the inferred network. For the network inference, we applied linear regression modeling with elastic net regularization on matched microRNA and messenger RNA expression profiling data to perform feature selection on prior knowledge from sequence-based target prediction resources. The novelty of miRlastic inference originates in predicting data-driven intra-transcriptome regulatory relationships through feature selection. With synthetic data, we showed that miRlastic outperformed commonly used methods and was suitable even for low sample sizes. To gain insight into the functional role of miRNAs and to determine joint functional properties of miRNA clusters, we introduced a local enrichment analysis procedure. The principle of this procedure lies in identifying regions of high functional similarity by evaluating the shortest paths between genes in the network. We can finally assign functional roles to the miRNAs by taking their regulatory relationships into account. We thoroughly evaluated miRlastic on a cohort of head and neck cancer (HNSCC) patients provided by The Cancer Genome Atlas. We inferred an mi-/mRNA regulatory network for human papilloma virus (HPV)-associated miRNAs in HNSCC. The resulting network best enriched for experimentally validated miRNA-target interaction, when compared to common methods. Finally, the local enrichment step identified two functional clusters of miRNAs that

  16. A quantitative evidence base for population health: applying utilization-based cluster analysis to segment a patient population.

    PubMed

    Vuik, Sabine I; Mayer, Erik; Darzi, Ara

    2016-11-25

    To improve population health it is crucial to understand the different care needs within a population. Traditional population groups are often based on characteristics such as age or morbidities. However, this does not take into account specific care needs across care settings and tends to focus on high-needs patients only. This paper explores the potential of using utilization-based cluster analysis to segment a general patient population into homogenous groups. Administrative datasets covering primary and secondary care were used to construct a database of 300,000 patients, which included socio-demographic variables, morbidities, care utilization, and cost. A k-means cluster analysis grouped the patients into segments with distinct care utilization, based on six utilization variables: non-elective inpatient admissions, elective inpatient admissions, outpatient visits, GP practice visits, GP home visits, and prescriptions. These segments were analyzed post-hoc to understand their morbidity and demographic profile. Eight population segments were identified, and utilization of each care setting was significantly different across all segments. Each segment also presented with different morbidity patterns and demographic characteristics, creating eight distinct care user types. Comparing these segments to traditional patient groups shows the heterogeneity of these approaches, especially for lower-needs patients. This analysis shows that utilization-based cluster analysis segments a patient population into distinct groups with unique care priorities, providing a quantitative evidence base to improve population health. Contrary to traditional methods, this approach also segments lower-needs populations, which can be used to inform preventive interventions. In addition, the identification of different care user types provides insight into needs across the care continuum.

  17. ECL-cell histamine mobilization in conscious rats: effects of locally applied regulatory peptides, candidate neurotransmitters and inflammatory mediators.

    PubMed

    Norlén, P; Bernsand, M; Konagaya, T; Håkanson, R

    2001-12-01

    1. The ECL cells control gastric acid secretion by mobilizing histamine in response to circulating gastrin. In addition, the ECL cells are thought to operate under nervous control and to be influenced by local inflammatory processes. 2. The purpose of the present study was to monitor histamine mobilization from ECL cells in conscious rats in response to locally applied regulatory peptides, candidate neurotransmitters and inflammatory mediators. 3. Microdialysis probes were implanted in the submucosa of the acid-producing part of the rat stomach. Three days later, the agents to be tested were administered via the microdialysis probe and their effects on basal (48 h fast) and stimulated (intravenous infusion of gastrin-17, 3 nmol kg(-1) h(-1)) mobilization of ECL-cell histamine was monitored by continuous measurement of histamine in the perfusate (radioimmunoassay). 4. Locally administered gastrin-17 and sulfated cholecystokinin-8 mobilized histamine as did pituitary adenylate cyclase-activating peptide-27, vasoactive intestinal peptide, peptide YY, met-enkephalin, endothelin and noradrenaline, adrenaline and isoprenaline. 5. While gastrin, sulfated-cholecystokinin-8, met-enkephalin and isoprenaline induced a sustained elevation of the submucosal histamine concentration, endothelin, peptide YY, pituitary adenylate cyclase activating peptide, vasoactive intestinal peptide, noradrenaline and adrenaline induced a transient elevation. 6. Calcitonin gene-related peptide, galanin, somatostatin and the prostanoid misoprostol inhibited gastrin-stimulated histamine mobilization. 7. The gut hormones neurotensin and secretin and the neuropeptides gastrin-releasing peptide, neuropeptide Y and substance P failed to affect ECL-cell histamine mobilization, while motilin and neuromedin U-25 had weak stimulatory effects. Also acetylcholine, carbachol, serotonin and the amino acid neurotransmitters aspartate, gamma-aminobutyric acid, glutamate and glycine were inactive or weakly

  18. An Unusual Cluster of Low-Frequency Earthquakes at Mount Baker, Washington, as Detected by a Local Broadband Network

    NASA Astrophysics Data System (ADS)

    Caplan-Auerbach, J.; Thelen, W. A.; Moran, S. C.

    2009-12-01

    A recent cluster of shallow low-frequency earthquakes on Mount Baker volcano marks one of the most seismically active periods in the volcano’s instrumented history (since 1972). Although Mount Baker, the northernmost of the U. S. Cascade volcanoes, has a history of recorded unrest (including an episode of geothermal unrest in 1975-6), it has never exhibited high levels of seismicity. Most of Baker’s seismicity has been associated with glacial earthquakes and deep long-period events. However, between June and September 2009 at least 39 low-frequency events were recorded at Mount Baker, 21 of which were located by the Pacific Northwest Seismic Network (PNSN). Locations are shallow and are scattered over a 5 x 5 km area around the southwest flank of the edifice. However, waveform similarity between many events suggests that most are located fairly close together and that the scatter apparent in PNSN locations is largely because of picking errors and a sparse network. To better constrain earthquake locations and source mechanism, a network of five broadband seismometers was deployed on Mount Baker between July and October 2009. This network greatly reduced the magnitude threshold for locatable events, with approximately three times as many earthquakes located by the local network than with the existing regional network. The additional stations also provided better depth constraints. The local network detected a larger number of events than identical temporary networks deployed in 2007 and 2008, suggesting that the increase in seismicity is real. Earthquakes located with the addition of data from the local network still locate at shallow depths beneath the southwest flank, but location uncertainty is significantly improved. We are using waveform similarity to evaluate relative event locations and investigate possible source mechanisms for the earthquakes, and are developing a more accurate velocity model that includes station elevations. This will better determine

  19. Dynamical cluster decay model applied to very light mass compound systems of mass A~30 formed in heavy ion reactions

    NASA Astrophysics Data System (ADS)

    Bikram Singh, Bir; Kaur, Mandeep; Sharma, Manoj K.; Gupta, Raj K.

    2014-12-01

    The study of the decay of 32S* and 31P* compound systems formed in 20Ne+12C and 19F+12C reactions, respectively, is further extended on the basis of collective clusterization process within the dynamical cluster model (DCM) of Gupta and collaborators, with the effects of deformations and orientations included, at an excitation energy E*CN=60 MeV. In the present study, we have investigated the effects of deformations and orientations on the target, i.e., 12C like yield, denoted C-yield (σC), which contains fusion-fission (FF) decay cross-section, σFF, from compound nucleus process and deep inelastic orbiting (DIO) cross-section, σD1O, from non-compound nucleus process. As observed in one of our earlier study for 32S* system there is a competition between FF and DIO, while, for 31P* there is a contribution of FF cross-section only, in the total C-yield. The comparative analysis of C-Yield for the considerations of spherical and oriented nuclei, shows similar results with the only difference of the values of neck length parameter (ΔR), which are more for the later case. The calculated cross-sections ac show good agreement with experimental data for both the considerations.

  20. Temporal clustering of flow events: Application of a stochastic framework applied to hormone transport and preferential flow

    NASA Astrophysics Data System (ADS)

    McGrath, G. S.; Gall, H. E.; Lin, H.; Rao, P. S.; Hopkins, I.; Mina, O.; Scanlan, C.

    2016-12-01

    The description of rainfall as a stochastic Poisson process has led to many advances in our understanding of the variability in hydrologial processes and associated solute transport. An assumption that has been proliferating in the application of such models is that a simple filtering of the rainfall by a hydrological threshold can be reasonably represented by a Poisson process with a modified rate parameter. We developed a simple stochastic description of this filtering and endeavoured to evaluate how the Poisson assumption impacts the modelling of water and chemical loads by threshold flow processes like preferential flow and surface runoff. Temporal clustering of these flow events, invalidating the Poisson assumption, leads to similar mean water flows and chemical loads albeit with significantly lower variability. When tested against preferential flow data and hormone transport from fields, both of which were from humid areas, the Poisson assumption was found to be reasonable, consistent with the stochastic modelling. The results of the stochastic modelling however do suggest that there are many circumstances, e.g. semi-arid areas or systems with significant soil-moisture memory, where the Poisson filtering should be considered more critically as temporally clustered events contribute significantly to solute load variability.

  1. Fuzzy Clustering Applied to ROI Detection in Helical Thoracic CT Scans with a New Proposal and Variants

    PubMed Central

    Castro, Alfonso; Boveda, Carmen; Arcay, Bernardino; Sanjurjo, Pedro

    2016-01-01

    The detection of pulmonary nodules is one of the most studied problems in the field of medical image analysis due to the great difficulty in the early detection of such nodules and their social impact. The traditional approach involves the development of a multistage CAD system capable of informing the radiologist of the presence or absence of nodules. One stage in such systems is the detection of ROI (regions of interest) that may be nodules in order to reduce the space of the problem. This paper evaluates fuzzy clustering algorithms that employ different classification strategies to achieve this goal. After characterising these algorithms, the authors propose a new algorithm and different variations to improve the results obtained initially. Finally it is shown as the most recent developments in fuzzy clustering are able to detect regions that may be nodules in CT studies. The algorithms were evaluated using helical thoracic CT scans obtained from the database of the LIDC (Lung Image Database Consortium). PMID:27517049

  2. Effect of Facilitation of Local Maternal-and-Newborn Stakeholder Groups on Neonatal Mortality: Cluster-Randomized Controlled Trial.

    PubMed

    Persson, Lars Åke; Nga, Nguyen T; Målqvist, Mats; Thi Phuong Hoa, Dinh; Eriksson, Leif; Wallin, Lars; Selling, Katarina; Huy, Tran Q; Duc, Duong M; Tiep, Tran V; Thi Thu Thuy, Vu; Ewald, Uwe

    2013-01-01

    Facilitation of local women's groups may reportedly reduce neonatal mortality. It is not known whether facilitation of groups composed of local health care staff and politicians can improve perinatal outcomes. We hypothesised that facilitation of local stakeholder groups would reduce neonatal mortality (primary outcome) and improve maternal, delivery, and newborn care indicators (secondary outcomes) in Quang Ninh province, Vietnam. In a cluster-randomized design 44 communes were allocated to intervention and 46 to control. Laywomen facilitated monthly meetings during 3 years in groups composed of health care staff and key persons in the communes. A problem-solving approach was employed. Births and neonatal deaths were monitored, and interviews were performed in households of neonatal deaths and of randomly selected surviving infants. A latent period before effect is expected in this type of intervention, but this timeframe was not pre-specified. Neonatal mortality rate (NMR) from July 2008 to June 2011 was 16.5/1,000 (195 deaths per 11,818 live births) in the intervention communes and 18.4/1,000 (194 per 10,559 live births) in control communes (adjusted odds ratio [OR] 0.96 [95% CI 0.73-1.25]). There was a significant downward time trend of NMR in intervention communes (p = 0.003) but not in control communes (p = 0.184). No significant difference in NMR was observed during the first two years (July 2008 to June 2010) while the third year (July 2010 to June 2011) had significantly lower NMR in intervention arm: adjusted OR 0.51 (95% CI 0.30-0.89). Women in intervention communes more frequently attended antenatal care (adjusted OR 2.27 [95% CI 1.07-4.8]). A randomized facilitation intervention with local stakeholder groups composed of primary care staff and local politicians working for three years with a perinatal problem-solving approach resulted in increased attendance to antenatal care and reduced neonatal mortality after a latent period.

  3. First-principles local density approximation (generalized gradient approximation) +U study of catalytic CenOm clusters: U value differs from bulk.

    PubMed

    Li, S F; Lu, Heqiang; Li, Pinglin; Yang, Zongxian; Guo, Z X

    2008-04-28

    Ceria possesses strong catalytic properties for CONO(x) removal and H(2) production. Clusters often show more intriguing functionalities than their bulk counterparts. Here, the geometric and electronic structures of Ce(n)O(m) (n=1-4,m=2n-1,2n) clusters are studied for the first time using the projected augmented wave method in density functional theory with detailed assessment of the exchange-correlation functional and the Hubbard parameter U. We note that the U value strongly affects the electronic structures of the oxygen-deficient Ce(n)O(2n-1) clusters, though less so on the stoichiometric Ce(n)O(2n). Furthermore, the local density approximation (LDA)+U method is more accurate than the generalized gradient approximation+U in describing the localization of the 4f electrons of the Ce(n)O(m) clusters. The calculated vibration frequency of the CeO molecule with the LDA+U (U=4 eV) is 818.4 cm(-1), in close agreement with experimental values of 820-825 cm(-1) for the low lying states. Different optimal U values were noted for the ceria cluster (4 eV) and its bulk (6 eV), due to quantum-size and geometric effects. The largely reduced formation energy of an oxygen vacancy indicates that the catalytic effect of the Ce(n)O(m) clusters are far greater than bulk CeO(2).

  4. Molecular-based rapid inventories of sympatric diversity: a comparison of DNA barcode clustering methods applied to geography-based vs clade-based sampling of amphibians.

    PubMed

    Paz, Andrea; Crawford, Andrew J

    2012-11-01

    Molecular markers offer a universal source of data for quantifying biodiversity. DNA barcoding uses a standardized genetic marker and a curated reference database to identify known species and to reveal cryptic diversity within wellsampled clades. Rapid biological inventories, e.g. rapid assessment programs (RAPs), unlike most barcoding campaigns, are focused on particular geographic localities rather than on clades. Because of the potentially sparse phylogenetic sampling, the addition of DNA barcoding to RAPs may present a greater challenge for the identification of named species or for revealing cryptic diversity. In this article we evaluate the use of DNA barcoding for quantifying lineage diversity within a single sampling site as compared to clade-based sampling, and present examples from amphibians. We compared algorithms for identifying DNA barcode clusters (e.g. species, cryptic species or Evolutionary Significant Units) using previously published DNA barcode data obtained from geography-based sampling at a site in Central Panama, and from clade-based sampling in Madagascar. We found that clustering algorithms based on genetic distance performed similarly on sympatric as well as clade-based barcode data, while a promising coalescent-based method performed poorly on sympatric data. The various clustering algorithms were also compared in terms of speed and software implementation. Although each method has its shortcomings in certain contexts, we recommend the use of the ABGD method, which not only performs fairly well under either sampling method, but does so in a few seconds and with a user-friendly Web interface.

  5. Ohio's statewide land use inventory: An operational approach for applying LANDSAT data to state, regional and local planning programs

    NASA Technical Reports Server (NTRS)

    Baldridge, P. E.; Geosling, P. H.; Leone, F.; Minshall, C.; Rodgers, R. H.; Wilhelm, C. L.

    1975-01-01

    The programmatic, technical, user application, and cost factors associated with the development of an operational, statewide land use inventory from LANDSAT data are described. The LANDSAT multispectral data are subjected to geometrical and categorical processing to produce map files for each of the 200 fifteen (15) minute quads covering Ohio. Computer compatible tapes are rescanned to produce inventory tapes which identify eight (8) Level I land use categories and a variety of Level II categories. The inventory tapes are processed through a series of ten (10) software programs developed by the State of Ohio. The net result is a computerized inventory which can be displayed in map or tabular form for various geographic units, at a variety of scales and for selected categories of usage. The computerized inventory data files are applied to technical programs developed by the various state agencies to be used in state, regional, and local planning programs.

  6. Lead-time reduction utilizing lean tools applied to healthcare: the inpatient pharmacy at a local hospital.

    PubMed

    Al-Araidah, Omar; Momani, Amer; Khasawneh, Mohammad; Momani, Mohammed

    2010-01-01

    The healthcare arena, much like the manufacturing industry, benefits from many aspects of the Toyota lean principles. Lean thinking contributes to reducing or eliminating nonvalue-added time, money, and energy in healthcare. In this paper, we apply selected principles of lean management aiming at reducing the wasted time associated with drug dispensing at an inpatient pharmacy at a local hospital. Thorough investigation of the drug dispensing process revealed unnecessary complexities that contribute to delays in delivering medications to patients. We utilize DMAIC (Define, Measure, Analyze, Improve, Control) and 5S (Sort, Set-in-order, Shine, Standardize, Sustain) principles to identify and reduce wastes that contribute to increasing the lead-time in healthcare operations at the pharmacy understudy. The results obtained from the study revealed potential savings of > 45% in the drug dispensing cycle time.

  7. Local Arp2/3-dependent actin assembly modulates applied traction force during apCAM adhesion site maturation.

    PubMed

    Buck, Kenneth B; Schaefer, Andrew W; Schoonderwoert, Vincent T; Creamer, Matthew S; Dufresne, Eric R; Forscher, Paul

    2017-01-01

    Homophilic binding of immunoglobulin superfamily molecules such as the Aplysia cell adhesion molecule (apCAM) leads to actin filament assembly near nascent adhesion sites. Such actin assembly can generate significant localized forces that have not been characterized in the larger context of axon growth and guidance. We used apCAM-coated bead substrates applied to the surface of neuronal growth cones to characterize the development of forces evoked by varying stiffness of mechanical restraint. Unrestrained bead propulsion matched or exceeded rates of retrograde network flow and was dependent on Arp2/3 complex activity. Analysis of growth cone forces applied to beads at low stiffness of restraint revealed switching between two states: frictional coupling to retrograde flow and Arp2/3-dependent propulsion. Stiff mechanical restraint led to formation of an extensive actin cup matching the geometric profile of the bead target and forward growth cone translocation; pharmacological inhibition of the Arp2/3 complex or Rac attenuated F-actin assembly near bead binding sites, decreased the efficacy of growth responses, and blocked accumulation of signaling molecules associated with nascent adhesions. These studies introduce a new model for regulation of traction force in which local actin assembly forces buffer nascent adhesion sites from the mechanical effects of retrograde flow. © 2017 Buck et al. This article is distributed by The American Society for Cell Biology under license from the author(s). Two months after publication it is available to the public under an Attribution–Noncommercial–Share Alike 3.0 Unported Creative Commons License (http://creativecommons.org/licenses/by-nc-sa/3.0).

  8. Examination of the hydrogen-bonding networks in small water clusters (n = 2-5, 13, 17) using absolutely localized molecular orbital energy decomposition analysis.

    PubMed

    Cobar, Erika A; Horn, Paul R; Bergman, Robert G; Head-Gordon, Martin

    2012-11-28

    Using the ωB97X-D and B3LYP density functionals, the absolutely localized molecular orbital energy decomposition method (ALMO-EDA) is applied to the water dimer through pentamer, 13-mer and 17-mer clusters. Two-body, three-body, and total interaction energies are decomposed into their component energy terms: frozen density interaction energy, polarization energy, and charge transfer energy. Charge transfer, polarization, and frozen orbital interaction energies are all found to be significant contributors to the two-body and total interaction energies; the three-body interaction energies are dominated by polarization. Each component energy term for the two-body interactions is highly dependent on the associated hydrogen bond distance. The favorability of the three-body terms associated with the 13- and 17-mer structures depends on the hydrogen-donor or hydrogen-acceptor roles played by each of the three component waters. Only small errors arise from neglect of three-body interactions without two adjacent water molecules, or beyond three-body interactions. Interesting linear correlations are identified between the contributions of charge-transfer and polarization terms to the two and three-body interactions, which permits elimination of explicit calculation of charge transfer to a good approximation.

  9. Effect of quenching temperature and size on atom movement and local structural change for small copper clusters containing 51-54 atoms during quenching processes

    NASA Astrophysics Data System (ADS)

    Zhang, L.; Fan, Q. N.

    2016-01-01

    Structural changes are sensitive to the atom number for the small size clusters. However, it is hardly predicted for the effects of quenching temperature and contained atom number on the atom movements of these clusters with the modification of a removing or adding atom. In this paper, we demonstrate the formation of many topologically non-equivalent Cu clusters containing 51-54 atoms during quenching processes by means of atomistic simulations. By modifying annealing temperature, different pathways are observed. The simulation results show that the quenching temperature has large effect on the atom movements and the scenario of the formation and growth of local structures in the clusters is greatly different for the four clusters only with one atom difference. When the quenching temperature is high, most atoms in the clusters move individually. In the meantime, changes in the atom packing can be observed in these clusters. Low quenching temperature is helpful to slow down the atom movements and form the structures on icosahedral geometry.

  10. Lower Arm Muscle Activation during Indirect-Localized Vibration: The Influence of Skill Levels When Applying Different Acceleration Loads.

    PubMed

    Padulo, Johnny; Di Giminiani, Riccardo; Dello Iacono, Antonio; Zagatto, Alessandro M; Migliaccio, Gian M; Grgantov, Zoran; Ardigò, Luca P

    2016-01-01

    We investigated the electromyographic response to synchronous indirect-localized vibration interventions in international and national table tennis players. Twenty-six male table tennis players, in a standing position, underwent firstly an upper arms maximal voluntary contraction and thereafter two different 30-s vibration interventions in random order: high acceleration load (peak acceleration = 12.8 g, frequency = 40 Hz; peak-to-peak displacement = 4.0 mm), and low acceleration load (peak acceleration = 7.2 g, frequency = 30 Hz, peak-to-peak displacement = 4.0 mm). Surface electromyography root mean square from brachioradialis, extensor digitorum, flexor carpi radialis, and flexor digitorum superficialis recorded during the two vibration interventions was normalized to the maximal voluntary contraction recording. Normalized surface electromyography root mean square was higher in international table tennis players with respect to national ones in all the interactions between muscles and vibration conditions (P < 0.05), with the exception of flexor carpi radialis (at low acceleration load, P > 0.05). The difference in normalized surface electromyography root mean square between international table tennis players and national ones increased in all the muscles with high acceleration load (P < 0.05), with the exception of flexor digitorum superficialis (P > 0.05). The muscle activation during indirect-localized vibration seems to be both skill level and muscle dependent. These results can optimize the training intervention in table tennis players when applying indirect-localized vibration to lower arm muscles. Future investigations should discriminate between middle- and long-term adaptations in response to specific vibration loads.

  11. Locally applied macrophage-activating lipopeptide-2 (MALP-2) promotes early vascularization of implanted porous polyethylene (Medpor®).

    PubMed

    Laschke, M W; Augustin, V; Kleer, S; Tschernig, T; Menger, M D

    2014-11-01

    Porous polyethylene (Medpor®) is frequently used in craniofacial reconstructive surgery. Rapid vascularization of the biomaterial crucially contributes to its adequate incorporation without complications. Macrophage-activating lipopeptide-2 (MALP-2) is a toll-like receptor (TLR)-2/6 agonist with pro-angiogenic properties. Herein we analyzed whether local single-shot application of MALP-2 improves the angiogenic host tissue response to Medpor®. Medpor® (3 mm×3 mm×0.25 mm) was implanted into dorsal skinfold chambers of BALB/c mice topically exposed to different MALP-2 doses (0.1 and 0.5 μg) or vehicle (control). The vascularization of the implants and the inflammatory foreign body reaction was analyzed using intravital fluorescence microscopy, histology and immunohistochemistry over 14 days. MALP-2 treatment dose-dependently improved the vascularization of Medpor®, as indicated by a significantly higher functional microvessel density at the border and center of the implants when compared to controls. This was associated with a temporary increase of adherent leukocytes in host tissue venules during the first 3 days after implantation. At day 14, implants in MALP-2-treated chambers were surrounded by granulation tissue, which exhibited a significantly higher density of CD31-positive microvessels and number of F4/80-positive macrophages when compared to controls. Additional biomaterial-free chambers did not show any signs of angiogenesis when treated with MALP-2. This indicates that locally applied MALP-2 effectively stimulates the early vascularization of Medpor® without inducing any local or systemic side effects. Accordingly, this easy approach may further improve the rapid incorporation of this biomaterial at the implantation site.

  12. Lower Arm Muscle Activation during Indirect-Localized Vibration: The Influence of Skill Levels When Applying Different Acceleration Loads

    PubMed Central

    Padulo, Johnny; Di Giminiani, Riccardo; Dello Iacono, Antonio; Zagatto, Alessandro M.; Migliaccio, Gian M.; Grgantov, Zoran; Ardigò, Luca P.

    2016-01-01

    We investigated the electromyographic response to synchronous indirect-localized vibration interventions in international and national table tennis players. Twenty-six male table tennis players, in a standing position, underwent firstly an upper arms maximal voluntary contraction and thereafter two different 30-s vibration interventions in random order: high acceleration load (peak acceleration = 12.8 g, frequency = 40 Hz; peak-to-peak displacement = 4.0 mm), and low acceleration load (peak acceleration = 7.2 g, frequency = 30 Hz, peak-to-peak displacement = 4.0 mm). Surface electromyography root mean square from brachioradialis, extensor digitorum, flexor carpi radialis, and flexor digitorum superficialis recorded during the two vibration interventions was normalized to the maximal voluntary contraction recording. Normalized surface electromyography root mean square was higher in international table tennis players with respect to national ones in all the interactions between muscles and vibration conditions (P < 0.05), with the exception of flexor carpi radialis (at low acceleration load, P > 0.05). The difference in normalized surface electromyography root mean square between international table tennis players and national ones increased in all the muscles with high acceleration load (P < 0.05), with the exception of flexor digitorum superficialis (P > 0.05). The muscle activation during indirect-localized vibration seems to be both skill level and muscle dependent. These results can optimize the training intervention in table tennis players when applying indirect-localized vibration to lower arm muscles. Future investigations should discriminate between middle- and long-term adaptations in response to specific vibration loads. PMID:27378948

  13. Probing the concepts of the Local Effect Model: The relevance of damage clustering on the nanometer and micrometer scale

    NASA Astrophysics Data System (ADS)

    Scholz, Michael; Friedrich, Thomas; Durante, Marco; Scholz, Uwe; Tommasino, Francesco; Herr, Lisa

    The Local Effect Model (LEM) allows predicting biological effects of ion beams on the basis of amorphous track structure in combination with the known dose response curves for photon radiation. In the recent version LEM IV (Elsässer et al. 2010), track structure and the observable biological effect are linked via the microscopic spatial DSB distribution that is induced by particle traversals through the cell nucleus. In order to determine this distribution, clustering of damages on two different scales, namely the nanometer and the micrometer scale, are particularly considered. On the nanometer scale, due to the extremely high ionization density in the center of tracks the simultaneous induction of two SSB in close vicinity by two independent secondary electrons becomes probable. As a result, additional DSB can be induced, so that a higher yield of DSB as compared to photon radiation is expected. On the micrometer scale, the spatial distribution of DSB with respect to higher order chromatin structure allows the definition of two damage classes. If two or more DSB are induced within chromatin loops of about 2 Mbp size (so called clustered DSB, cDSB) this damage class is assumed to be linked to a significantly increased lethality as compared to the case of a single, isolated DSB (iDSB) induced in a chromatin loop. In the talk, the basic principles of the LEM IV will be briefly reviewed. The focus will then be on the discussion of signatures in radiation response that are expected as a consequence of the above mentioned clustering processes. In order to validate the relevance of these processes, the concept of the LEM is transferred to additional endpoints, e.g. the kinetics of DSB rejoining, as well as to other radiation qualities like high-energy (typically MeV) and ultrasoft (typically keV) photon radiation. First, we briefly discuss the transfer of the concept to high energetic photon radiation that allows explaining the linear quadratic shape of the photon dose

  14. MR image segmentation and bias field estimation based on coherent local intensity clustering with total variation regularization.

    PubMed

    Tu, Xiaoguang; Gao, Jingjing; Zhu, Chongjing; Cheng, Jie-Zhi; Ma, Zheng; Dai, Xin; Xie, Mei

    2016-12-01

    Though numerous segmentation algorithms have been proposed to segment brain tissue from magnetic resonance (MR) images, few of them consider combining the tissue segmentation and bias field correction into a unified framework while simultaneously removing the noise. In this paper, we present a new unified MR image segmentation algorithm whereby tissue segmentation, bias correction and noise reduction are integrated within the same energy model. Our method is presented by a total variation term introduced to the coherent local intensity clustering criterion function. To solve the nonconvex problem with respect to membership functions, we add auxiliary variables in the energy function such as Chambolle's fast dual projection method can be used and the optimal segmentation and bias field estimation can be achieved simultaneously throughout the reciprocal iteration. Experimental results show that the proposed method has a salient advantage over the other three baseline methods on either tissue segmentation or bias correction, and the noise is significantly reduced via its applications on highly noise-corrupted images. Moreover, benefiting from the fast convergence of the proposed solution, our method is less time-consuming and robust to parameter setting.

  15. Applying Multivariate Clustering Techniques to Health Data: The 4 Types of Healthcare Utilization in the Paris Metropolitan Area

    PubMed Central

    Lefèvre, Thomas; Rondet, Claire; Parizot, Isabelle; Chauvin, Pierre

    2014-01-01

    Background Cost containment policies and the need to satisfy patients’ health needs and care expectations provide major challenges to healthcare systems. Identification of homogeneous groups in terms of healthcare utilisation could lead to a better understanding of how to adjust healthcare provision to society and patient needs. Methods This study used data from the third wave of the SIRS cohort study, a representative, population-based, socio-epidemiological study set up in 2005 in the Paris metropolitan area, France. The data were analysed using a cross-sectional design. In 2010, 3000 individuals were interviewed in their homes. Non-conventional multivariate clustering techniques were used to determine homogeneous user groups in data. Multinomial models assessed a wide range of potential associations between user characteristics and their pattern of healthcare utilisation. Results We identified four distinct patterns of healthcare use. Patterns of consumption and the socio-demographic characteristics of users differed qualitatively and quantitatively between these four profiles. Extensive and intensive use by older, wealthier and unhealthier people contrasted with narrow and parsimonious use by younger, socially deprived people and immigrants. Rare, intermittent use by young healthy men contrasted with regular targeted use by healthy and wealthy women. Conclusion The use of an original technique of massive multivariate analysis allowed us to characterise different types of healthcare users, both in terms of resource utilisation and socio-demographic variables. This method would merit replication in different populations and healthcare systems. PMID:25506916

  16. Applying multivariate clustering techniques to health data: the 4 types of healthcare utilization in the Paris metropolitan area.

    PubMed

    Lefèvre, Thomas; Rondet, Claire; Parizot, Isabelle; Chauvin, Pierre

    2014-01-01

    Cost containment policies and the need to satisfy patients' health needs and care expectations provide major challenges to healthcare systems. Identification of homogeneous groups in terms of healthcare utilisation could lead to a better understanding of how to adjust healthcare provision to society and patient needs. This study used data from the third wave of the SIRS cohort study, a representative, population-based, socio-epidemiological study set up in 2005 in the Paris metropolitan area, France. The data were analysed using a cross-sectional design. In 2010, 3000 individuals were interviewed in their homes. Non-conventional multivariate clustering techniques were used to determine homogeneous user groups in data. Multinomial models assessed a wide range of potential associations between user characteristics and their pattern of healthcare utilisation. We identified four distinct patterns of healthcare use. Patterns of consumption and the socio-demographic characteristics of users differed qualitatively and quantitatively between these four profiles. Extensive and intensive use by older, wealthier and unhealthier people contrasted with narrow and parsimonious use by younger, socially deprived people and immigrants. Rare, intermittent use by young healthy men contrasted with regular targeted use by healthy and wealthy women. The use of an original technique of massive multivariate analysis allowed us to characterise different types of healthcare users, both in terms of resource utilisation and socio-demographic variables. This method would merit replication in different populations and healthcare systems.

  17. Proposing a conceptual framework for integrated local public health policy, applied to childhood obesity - the behavior change ball

    PubMed Central

    2013-01-01

    Background Childhood obesity is a ‘wicked’ public health problem that is best tackled by an integrated approach, which is enabled by integrated public health policies. The development and implementation of such policies have in practice proven to be difficult, however, and studying why this is the case requires a tool that may assist local policy-makers and those assisting them. A comprehensive framework that can help to identify options for improvement and to systematically develop solutions may be used to support local policy-makers. Discussion We propose the ‘Behavior Change Ball’ as a tool to study the development and implementation of integrated public health policies within local government. Based on the tenets of the ‘Behavior Change Wheel’ by Michie and colleagues (2011), the proposed conceptual framework distinguishes organizational behaviors of local policy-makers at the strategic, tactical and operational levels, as well as the determinants (motivation, capability, opportunity) required for these behaviors, and interventions and policy categories that can influence them. To illustrate the difficulty of achieving sustained integrated approaches, we use the metaphor of a ball in our framework: the mountainous landscapes surrounding the ball reflect the system’s resistance to change (by making it difficult for the ball to roll). We apply this framework to the problem of childhood obesity prevention. The added value provided by the framework lies in its comprehensiveness, theoretical basis, diagnostic and heuristic nature and face validity. Summary Since integrated public health policies have not been widely developed and implemented in practice, organizational behaviors relevant to the development of these policies remain to be investigated. A conceptual framework that can assist in systematically studying the policy process may facilitate this. Our Behavior Change Ball adds significant value to existing public health policy frameworks by

  18. Proposing a conceptual framework for integrated local public health policy, applied to childhood obesity--the behavior change ball.

    PubMed

    Hendriks, Anna-Marie; Jansen, Maria W J; Gubbels, Jessica S; De Vries, Nanne K; Paulussen, Theo; Kremers, Stef P J

    2013-04-18

    Childhood obesity is a 'wicked' public health problem that is best tackled by an integrated approach, which is enabled by integrated public health policies. The development and implementation of such policies have in practice proven to be difficult, however, and studying why this is the case requires a tool that may assist local policy-makers and those assisting them. A comprehensive framework that can help to identify options for improvement and to systematically develop solutions may be used to support local policy-makers. We propose the 'Behavior Change Ball' as a tool to study the development and implementation of integrated public health policies within local government. Based on the tenets of the 'Behavior Change Wheel' by Michie and colleagues (2011), the proposed conceptual framework distinguishes organizational behaviors of local policy-makers at the strategic, tactical and operational levels, as well as the determinants (motivation, capability, opportunity) required for these behaviors, and interventions and policy categories that can influence them. To illustrate the difficulty of achieving sustained integrated approaches, we use the metaphor of a ball in our framework: the mountainous landscapes surrounding the ball reflect the system's resistance to change (by making it difficult for the ball to roll). We apply this framework to the problem of childhood obesity prevention. The added value provided by the framework lies in its comprehensiveness, theoretical basis, diagnostic and heuristic nature and face validity. Since integrated public health policies have not been widely developed and implemented in practice, organizational behaviors relevant to the development of these policies remain to be investigated. A conceptual framework that can assist in systematically studying the policy process may facilitate this. Our Behavior Change Ball adds significant value to existing public health policy frameworks by incorporating multiple theoretical perspectives

  19. THE CLUSTER AND FIELD GALAXY ACTIVE GALACTIC NUCLEUS FRACTION AT z = 1-1.5: EVIDENCE FOR A REVERSAL OF THE LOCAL ANTICORRELATION BETWEEN ENVIRONMENT AND AGN FRACTION

    SciTech Connect

    Martini, Paul; Miller, E. D.; Bautz, M.; Brodwin, M.; Stanford, S. A.; Gonzalez, Anthony H.; Hickox, R. C.; Stern, D.; Eisenhardt, P. R.; Galametz, A.; Norman, D.; Dey, A.; Jannuzi, B. T.; Murray, S.; Jones, C.; Brown, M. J. I.

    2013-05-01

    The fraction of cluster galaxies that host luminous active galactic nuclei (AGNs) is an important probe of AGN fueling processes, the cold interstellar medium at the centers of galaxies, and how tightly black holes and galaxies co-evolve. We present a new measurement of the AGN fraction in a sample of 13 clusters of galaxies (M {>=} 10{sup 14} M{sub Sun }) at 1 < z < 1.5 selected from the Spitzer/IRAC Shallow Cluster Survey, as well as the field fraction in the immediate vicinity of these clusters, and combine these data with measurements from the literature to quantify the relative evolution of cluster and field AGN from the present to z {approx} 3. We estimate that the cluster AGN fraction at 1 < z < 1.5 is f{sub A} = 3.0{sup +2.4}{sub -1.4}% for AGNs with a rest-frame, hard X-ray luminosity greater than L{sub X,{sub H}} {>=} 10{sup 44} erg s{sup -1}. This fraction is measured relative to all cluster galaxies more luminous than M{sup *}{sub 3.6}(z) + 1, where M{sup *}{sub 3.6}(z) is the absolute magnitude of the break in the galaxy luminosity function at the cluster redshift in the IRAC 3.6 {mu}m bandpass. The cluster AGN fraction is 30 times greater than the 3{sigma} upper limit on the value for AGNs of similar luminosity at z {approx} 0.25, as well as more than an order of magnitude greater than the AGN fraction at z {approx} 0.75. AGNs with L{sub X,{sub H}} {>=} 10{sup 43} erg s{sup -1} exhibit similarly pronounced evolution with redshift. In contrast to the local universe, where the luminous AGN fraction is higher in the field than in clusters, the X-ray and MIR-selected AGN fractions in the field and clusters are consistent at 1 < z < 1.5. This is evidence that the cluster AGN population has evolved more rapidly than the field population from z {approx} 1.5 to the present. This environment-dependent AGN evolution mimics the more rapid evolution of star-forming galaxies in clusters relative to the field.

  20. A cluster randomised pragmatic trial applying Self-determination theory to type 2 diabetes care in general practice.

    PubMed

    Juul, Lise; Maindal, Helle T; Zoffmann, Vibeke; Frydenberg, Morten; Sandbaek, Annelli

    2011-11-24

    Treatment recommendations for prevention of type 2 diabetes complications often require radical and life-long health behaviour changes. Observational studies based on Self-determination theory (SDT) propose substantial factors for the maintenance of behaviour changes and concomitant well-being, but experimental research is needed to develop and evaluate SDT-based interventions. The aims of this paper were to describe 1) the design of a trial assessing the effectiveness of a training course for practice-nurses in autonomy support on patient-perceived motivation, HbA1, cholesterol, and well-being among a diabetes population, 2) the actual intervention to a level of detail that allows its replication, and 3) the connection between SDT recommendations for health care-provider behaviour and the content of the training course. The study is a cluster-randomised pragmatic trial including 40 Danish general practices with nurse-led diabetes consultations, and the associated diabetes population. The diabetes population was identified by registers (n = 4034).The intervention was a 16-hour course with interactive training for practice nurses. The course was delivered over 4 afternoons at Aarhus University and one 1/2 hour visit to the practice by one of the course-teachers over a period of 10 months (0, 2, 5, 10 mths.). The intervention is depicted by a PaT Plot showing the timeline and the characteristics of the intervention components.Effectiveness of the intervention will be assessed on the diabetes populations with regard to well-being (PAID, SF-12), HbA1c- and cholesterol-levels, perceived autonomy support (HCCQ), type of motivation (TSRQ), and perceived competence for diabetes care (PCD) 15-21 months after the core course; the completion of the second course afternoon. Data will be retrieved from registers and by questionnaires. Challenges and advantages of the pragmatic design are discussed. In a real-world setting, this study will determine the impact on motivation, Hb

  1. A cluster randomised pragmatic trial applying Self-determination theory to type 2 diabetes care in general practice

    PubMed Central

    2011-01-01

    Background Treatment recommendations for prevention of type 2 diabetes complications often require radical and life-long health behaviour changes. Observational studies based on Self-determination theory (SDT) propose substantial factors for the maintenance of behaviour changes and concomitant well-being, but experimental research is needed to develop and evaluate SDT-based interventions. The aims of this paper were to describe 1) the design of a trial assessing the effectiveness of a training course for practice-nurses in autonomy support on patient-perceived motivation, HbA1, cholesterol, and well-being among a diabetes population, 2) the actual intervention to a level of detail that allows its replication, and 3) the connection between SDT recommendations for health care-provider behaviour and the content of the training course. Methods/Design The study is a cluster-randomised pragmatic trial including 40 Danish general practices with nurse-led diabetes consultations, and the associated diabetes population. The diabetes population was identified by registers (n = 4034). The intervention was a 16-hour course with interactive training for practice nurses. The course was delivered over 4 afternoons at Aarhus University and one 1/2 hour visit to the practice by one of the course-teachers over a period of 10 months (0, 2, 5, 10 mths.). The intervention is depicted by a PaT Plot showing the timeline and the characteristics of the intervention components. Effectiveness of the intervention will be assessed on the diabetes populations with regard to well-being (PAID, SF-12), HbA1c- and cholesterol-levels, perceived autonomy support (HCCQ), type of motivation (TSRQ), and perceived competence for diabetes care (PCD) 15-21 months after the core course; the completion of the second course afternoon. Data will be retrieved from registers and by questionnaires. Discussion Challenges and advantages of the pragmatic design are discussed. In a real-world setting, this study will

  2. Effects of applied potential and the initial gap between electrodes on localized electrochemical deposition of micrometer copper columns

    NASA Astrophysics Data System (ADS)

    Wang, Fuliang; Xiao, Hongbin; He, Hu

    2016-05-01

    Micrometer copper columns were fabricated via a technology named localized electrochemical deposition (LECD). This paper studies the effects of applied potential and the initial gap between electrodes on the LECD process. The surface and cross sectional morphologies, as well as the average deposition rate were investigated to evaluate the quality of the deposited copper columns. Results demonstrated that the copper columns tended to be cylinder-shape with few voids inside at lower potential (<2.4 V). Whereas,the copper columns tended to be dendriform-shape with lots of voids inside at larger potential (>2.8 V). The average deposition rate increased with the raise of potential. In addition, the copper columns tended to be cylinder-shape with the initial gap between electrodes to be 10 μm or below. However, the copper columns tended to be cone-shape when the initial gap between electrodes became larger (35 μm or above). The number of voids inside the copper column and the average deposition rate both decreased with the increase of the initial gap. Moreover, the process of LECD under varied electric field has also been simulated using COMSOL software, and the formation of cylindrical and conical copper columns was further explained based on the electric field distribution at the cathode.

  3. Effects of applied potential and the initial gap between electrodes on localized electrochemical deposition of micrometer copper columns

    PubMed Central

    Wang, Fuliang; Xiao, Hongbin; He, Hu

    2016-01-01

    Micrometer copper columns were fabricated via a technology named localized electrochemical deposition (LECD). This paper studies the effects of applied potential and the initial gap between electrodes on the LECD process. The surface and cross sectional morphologies, as well as the average deposition rate were investigated to evaluate the quality of the deposited copper columns. Results demonstrated that the copper columns tended to be cylinder-shape with few voids inside at lower potential (<2.4 V). Whereas,the copper columns tended to be dendriform-shape with lots of voids inside at larger potential (>2.8 V). The average deposition rate increased with the raise of potential. In addition, the copper columns tended to be cylinder-shape with the initial gap between electrodes to be 10 μm or below. However, the copper columns tended to be cone-shape when the initial gap between electrodes became larger (35 μm or above). The number of voids inside the copper column and the average deposition rate both decreased with the increase of the initial gap. Moreover, the process of LECD under varied electric field has also been simulated using COMSOL software, and the formation of cylindrical and conical copper columns was further explained based on the electric field distribution at the cathode. PMID:27185742

  4. Initiating change locally in bullying and aggression through the school environment (INCLUSIVE) trial: update to cluster randomised controlled trial protocol.

    PubMed

    Bonell, Chris; Mathiot, Anne; Allen, Elizabeth; Bevilacqua, Leonardo; Christie, Deborah; Elbourne, Diana; Fletcher, Adam; Grieve, Richard; Legood, Rosa; Scott, Stephen; Warren, Emily; Wiggins, Meg; Viner, Russell M

    2017-05-25

    Systematic reviews suggest that multi-component interventions are effective in reducing bullying victimisation and perpetration. We are undertaking a phase III randomised trial of the INCLUSIVE multi-component intervention. This trial aims to assess the effectiveness and cost-effectiveness of the INCLUSIVE intervention in reducing aggression and bullying victimisation in English secondary schools. This paper updates the original trial protocol published in 2014 (Trials 15:381, 2014) and presents the changes in the process evaluation protocol and the secondary outcome data collection. The methods are summarised as follows. cluster randomised trial. 40 state secondary schools. Outcomes assessed among the cohort of students at the end of year 7 (n = 6667) at baseline. INCLUSIVE is a multi-component school intervention including a social and emotional learning curriculum, changes to school environment (an action group comprising staff and students reviews local data on needs to review rules and policies and determine other local actions) and staff training in restorative practice. The intervention will be delivered by schools supported in the first two years by educational facilitators independent of the research team, with a third intervention year involving no external facilitation but all other elements. Comparator: normal practice. Primary: Two primary outcomes at student level assessed at baseline and at 36 months: 1. Aggressive behaviours in school: Edinburgh Study of Youth Transitions and Crime school misbehaviour subscale (ESYTC) 2. Bullying and victimisation: Gatehouse Bullying Scale (GBS) Secondary outcomes assessed at baseline, 24 and 36 months will include measures relating to the economic evaluation, psychosocial outcomes in students and staff and school-level truancy and exclusion rates. 20 schools per arm will provide 90% power to identify an effect size of 0.25 SD with a 5% significance level. Randomisation: eligible consenting schools were

  5. Initiating change locally in bullying and aggression through the school environment (INCLUSIVE): study protocol for a cluster randomised controlled trial.

    PubMed

    Bonell, Chris; Allen, Elizabeth; Christie, Deborah; Elbourne, Diana; Fletcher, Adam; Grieve, Richard; LeGood, Rosa; Mathiot, Anne; Scott, Stephen; Wiggins, Meg; Viner, Russell M

    2014-09-30

    Systematic reviews suggest that interventions that address school organisation are effective in reducing victimisation and bullying. We successfully piloted a school environment intervention modified from international studies to incorporate 'restorative justice' approaches. This trial aims to establish the effectiveness and cost-effectiveness of the INCLUSIVE intervention in reducing aggression and bullying in English secondary schools. cluster randomised trial. 40 state-supported secondary schools. OUTCOMES assessed among the cohort of students in year 8 (n = approximately 6,000) in intervention year 1. INCLUSIVE is a school-led intervention which combines changes to the school environment with the promotion of social and emotional skills and restorative practices through: the formation of a school action group involving students and staff supported by an external facilitator to review local data on needs, determine priorities, and develop and implement an action plan for revising relevant school policies/rules and other actions to improve relationships at school and reduce aggression; staff training in restorative practices; and a new social and emotional skills curriculum. The intervention will be delivered by schools supported in the first two years by educational facilitators independent of the research team, with a third locally facilitated intervention year.Comparator: normal practice. primary: 2 primary outcomes at student level assessed at baseline and at 36 months:1. Aggressive behaviours in school: Edinburgh Study of Youth Transitions and Crime school misbehaviour subscale (ESYTC)2. Bullying and victimisation: Gatehouse Bullying Scale (GBS)Secondary outcomes assessed at baseline, 24 and 36 months will include measures relating to the economic evaluation, psychosocial outcomes in students and staff and school-level truancy and exclusion rates. 20 schools per arm will provide 90% power to identify an effect size of 0.25 SD with a 5% significance level

  6. Calculated organ doses using Monte Carlo simulations in a reference male phantom undergoing HDR brachytherapy applied to localized prostate carcinoma

    SciTech Connect

    Candela-Juan, Cristian; Perez-Calatayud, Jose; Ballester, Facundo; Rivard, Mark J.

    2013-03-15

    Purpose: The aim of this study was to obtain equivalent doses in radiosensitive organs (aside from the bladder and rectum) when applying high-dose-rate (HDR) brachytherapy to a localized prostate carcinoma using {sup 60}Co or {sup 192}Ir sources. These data are compared with results in a water phantom and with expected values in an infinite water medium. A comparison with reported values from proton therapy and intensity-modulated radiation therapy (IMRT) is also provided. Methods: Monte Carlo simulations in Geant4 were performed using a voxelized phantom described in International Commission on Radiological Protection (ICRP) Publication 110, which reproduces masses and shapes from an adult reference man defined in ICRP Publication 89. Point sources of {sup 60}Co or {sup 192}Ir with photon energy spectra corresponding to those exiting their capsules were placed in the center of the prostate, and equivalent doses per clinical absorbed dose in this target organ were obtained in several radiosensitive organs. Values were corrected to account for clinical circumstances with the source located at various positions with differing dwell times throughout the prostate. This was repeated for a homogeneous water phantom. Results: For the nearest organs considered (bladder, rectum, testes, small intestine, and colon), equivalent doses given by {sup 60}Co source were smaller (8%-19%) than from {sup 192}Ir. However, as the distance increases, the more penetrating gamma rays produced by {sup 60}Co deliver higher organ equivalent doses. The overall result is that effective dose per clinical absorbed dose from a {sup 60}Co source (11.1 mSv/Gy) is lower than from a {sup 192}Ir source (13.2 mSv/Gy). On the other hand, equivalent doses were the same in the tissue and the homogeneous water phantom for those soft tissues closer to the prostate than about 30 cm. As the distance increased, the differences of photoelectric effect in water and soft tissue, and appearance of other materials

  7. Adsorption of carbon monoxide on small aluminum oxide clusters: Role of the local atomic environment and charge state on the oxidation of the CO molecule.

    PubMed

    Ornelas-Lizcano, J C; Guirado-López, R A

    2015-03-28

    We present extensive density functional theory (DFT) calculations dedicated to analyze the adsorption behavior of CO molecules on small AlxOy (±) clusters. Following the experimental results of Johnson et al. [J. Phys. Chem. A 112, 4732 (2008)], we consider structures having the bulk composition Al2O3, as well as smaller Al2O2 and Al2O units. Our electron affinity and total energy calculations are consistent with aluminum oxide clusters having two-dimensional rhombus-like structures. In addition, interconversion energy barriers between two- and one-dimensional atomic arrays are of the order of 1 eV, thus clearly defining the preferred isomers. Single CO adsorption on our charged AlxOy (±) clusters exhibits, in general, spontaneous oxygen transfer events leading to the production of CO2 in line with the experimental data. However, CO can also bind to both Al and O atoms of the clusters forming aluminum oxide complexes with a CO2 subunit. The vibrational spectra of AlxOy + CO2 provides well defined finger prints that may allow the identification of specific isomers. The AlxOy (+) clusters are more reactive than the anionic species and the final Al2O(+) + CO reaction can result in the production of atomic Al and carbon dioxide as observed from experiments. We underline the crucial role played by the local atomic environment, charge density distribution, and spin-multiplicity on the oxidation behavior of CO molecules. Finally, we analyze the importance of coadsorption and finite temperature effects by performing DFT Born-Oppenheimer molecular dynamics. Our calculations show that CO oxidation on AlxOy (+) clusters can be also promoted by the binding of additional CO species at 300 K, revealing the existence of fragmentation processes in line with the ones experimentally inferred.

  8. Adsorption of carbon monoxide on small aluminum oxide clusters: Role of the local atomic environment and charge state on the oxidation of the CO molecule

    NASA Astrophysics Data System (ADS)

    Ornelas-Lizcano, J. C.; Guirado-López, R. A.

    2015-03-01

    We present extensive density functional theory (DFT) calculations dedicated to analyze the adsorption behavior of CO molecules on small AlxOy± clusters. Following the experimental results of Johnson et al. [J. Phys. Chem. A 112, 4732 (2008)], we consider structures having the bulk composition Al2O3, as well as smaller Al2O2 and Al2O units. Our electron affinity and total energy calculations are consistent with aluminum oxide clusters having two-dimensional rhombus-like structures. In addition, interconversion energy barriers between two- and one-dimensional atomic arrays are of the order of 1 eV, thus clearly defining the preferred isomers. Single CO adsorption on our charged AlxOy± clusters exhibits, in general, spontaneous oxygen transfer events leading to the production of CO2 in line with the experimental data. However, CO can also bind to both Al and O atoms of the clusters forming aluminum oxide complexes with a CO2 subunit. The vibrational spectra of AlxOy + CO2 provides well defined finger prints that may allow the identification of specific isomers. The AlxOy+ clusters are more reactive than the anionic species and the final Al2O+ + CO reaction can result in the production of atomic Al and carbon dioxide as observed from experiments. We underline the crucial role played by the local atomic environment, charge density distribution, and spin-multiplicity on the oxidation behavior of CO molecules. Finally, we analyze the importance of coadsorption and finite temperature effects by performing DFT Born-Oppenheimer molecular dynamics. Our calculations show that CO oxidation on AlxOy+ clusters can be also promoted by the binding of additional CO species at 300 K, revealing the existence of fragmentation processes in line with the ones experimentally inferred.

  9. LoCuSS: A DYNAMICAL ANALYSIS OF X-RAY ACTIVE GALACTIC NUCLEI IN LOCAL CLUSTERS

    SciTech Connect

    Haines, C. P.; Pereira, M. J.; Egami, E.; Sanderson, A. J. R.; Smith, G. P.; Babul, A.; Edge, A. C.; Finoguenov, A.; Moran, S. M.; Okabe, N.

    2012-08-01

    We present a study of the distribution of X-ray active galactic nuclei (AGNs) in a representative sample of 26 massive clusters at 0.15 < z < 0.30, combining Chandra observations sensitive to X-ray point sources of luminosity L{sub X} {approx} 10{sup 42} erg s{sup -1} at the cluster redshift with extensive and highly complete spectroscopy of cluster members down to {approx}M*{sub K} + 2. In total we identify 48 X-ray AGNs among the cluster members, with luminosities 2 Multiplication-Sign 10{sup 41}-1 Multiplication-Sign 10{sup 44} erg s{sup -1}. Based on these identifications, we estimate that 0.73% {+-} 0.14% of cluster galaxies brighter than M{sub K} = -23.1 (M*{sub K} + 1.5) host an X-ray AGN with L{sub X} > 10{sup 42} erg s{sup -1}. In the stacked caustic diagram that shows (v{sub los} - (v))/{sigma}{sub v} versus r{sub proj}/r{sub 500}, the X-ray AGN appear to preferentially lie along the caustics, suggestive of an infalling population. They also appear to avoid the region with lowest cluster-centric radii and relative velocities (r{sub proj} < 0.4r{sub 500}; |v - (v)|/{sigma}{sub v} < 0.8), which is dominated by the virialized population of galaxies accreted earliest into the clusters. The line-of-sight velocity histogram of the X-ray AGN shows a relatively flat distribution, and is inconsistent with the Gaussian distribution expected for a virialized population at 98.9% confidence. Moreover, the velocity dispersion of the 48 X-ray AGNs is 1.51 times that of the overall cluster population, which is consistent with the {radical}2 ratio expected by simple energetic arguments when comparing infalling versus virialized populations. This kinematic segregation is significant at the 4.66{sigma} level. When splitting the X-ray AGN sample into two according to X-ray or infrared (IR) luminosity, both X-ray bright (L{sub X} > 10{sup 42}) and IR-bright (L{sub TIR} > 2 Multiplication-Sign 10{sup 10} L{sub Sun }) subsamples show higher velocity dispersions than their X

  10. 20 CFR 668.825 - Does the WIA administrative cost limit for States and local areas apply to section 166 grants?

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 20 Employees' Benefits 4 2012-04-01 2012-04-01 false Does the WIA administrative cost limit for States and local areas apply to section 166 grants? 668.825 Section 668.825 Employees' Benefits EMPLOYMENT AND TRAINING ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED) INDIAN AND NATIVE AMERICAN...

  11. 20 CFR 668.825 - Does the WIA administrative cost limit for States and local areas apply to section 166 grants?

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 20 Employees' Benefits 4 2014-04-01 2014-04-01 false Does the WIA administrative cost limit for States and local areas apply to section 166 grants? 668.825 Section 668.825 Employees' Benefits EMPLOYMENT AND TRAINING ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED) INDIAN AND NATIVE AMERICAN...

  12. 20 CFR 668.825 - Does the WIA administrative cost limit for States and local areas apply to section 166 grants?

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 20 Employees' Benefits 4 2013-04-01 2013-04-01 false Does the WIA administrative cost limit for States and local areas apply to section 166 grants? 668.825 Section 668.825 Employees' Benefits EMPLOYMENT AND TRAINING ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED) INDIAN AND NATIVE AMERICAN...

  13. OmegaWINGS: The First Complete Census of Post-starburst Galaxies in Clusters in the Local Universe

    NASA Astrophysics Data System (ADS)

    Paccagnella, A.; Vulcani, B.; Poggianti, B. M.; Fritz, J.; Fasano, G.; Moretti, A.; Jaffé, Yara L.; Biviano, A.; Gullieuszik, M.; Bettoni, D.; Cava, A.; Couch, W.; D'Onofrio, M.

    2017-04-01

    Galaxies that abruptly interrupt their star formation in < 1.5 {Gyr} present recognizable features in their spectra (no emission and Hδ in absorption) and are called post-starburst (PSB) galaxies. By studying their stellar population properties and their location within the clusters, we obtain valuable insights on the physical processes responsible for star formation quenching. We present the first complete characterization of PSB galaxies in clusters at 0.04< z< 0.07, based on WINGS and OmegaWINGS data, and contrast their properties to those of passive (PAS) and emission-line (EML) galaxies. For V< 20, PSBs represent 7.2 ± 0.2% of cluster galaxies within 1.2 virial radii. Their incidence slightly increases from the outskirts toward the cluster center and from the least toward the most luminous and massive clusters, defined in terms of X-ray luminosity and velocity dispersion. The phase-space analysis and velocity-dispersion profile suggest that PSBs represent a combination of galaxies with different accretion histories. Moreover, PSBs with the strongest Hδ are consistent with being recently accreted. PSBs have stellar masses, magnitudes, colors, and morphologies intermediate between PAS and EML galaxies, typical of a population in transition from being star-forming to passive. Comparing the fraction of PSBs to the fraction of galaxies in transition on longer timescales, we estimate that the short-timescale star formation quenching channel contributes two times more than the long timescale one to the growth of the passive population. Processes like ram-pressure stripping and galaxy-galaxy interactions are more efficient than strangulation in affecting star formation.

  14. Trends and predictors of transmitted drug resistance (TDR) and clusters with TDR in a local Belgian HIV-1 epidemic.

    PubMed

    Pineda-Peña, Andrea-Clemencia; Schrooten, Yoeri; Vinken, Lore; Ferreira, Fossie; Li, Guangdi; Trovão, Nídia Sequeira; Khouri, Ricardo; Derdelinckx, Inge; De Munter, Paul; Kücherer, Claudia; Kostrikis, Leondios G; Nielsen, Claus; Littsola, Kirsi; Wensing, Annemarie; Stanojevic, Maja; Paredes, Roger; Balotta, Claudia; Albert, Jan; Boucher, Charles; Gomez-Lopez, Arley; Van Wijngaerden, Eric; Van Ranst, Marc; Vercauteren, Jurgen; Vandamme, Anne-Mieke; Van Laethem, Kristel

    2014-01-01

    We aimed to study epidemic trends and predictors for transmitted drug resistance (TDR) in our region, its clinical impact and its association with transmission clusters. We included 778 patients from the AIDS Reference Center in Leuven (Belgium) diagnosed from 1998 to 2012. Resistance testing was performed using population-based sequencing and TDR was estimated using the WHO-2009 surveillance list. Phylogenetic analysis was performed using maximum likelihood and Bayesian techniques. The cohort was predominantly Belgian (58.4%), men who have sex with men (MSM) (42.8%), and chronically infected (86.5%). The overall TDR prevalence was 9.6% (95% confidence interval (CI): 7.7-11.9), 6.5% (CI: 5.0-8.5) for nucleoside reverse transcriptase inhibitors (NRTI), 2.2% (CI: 1.4-3.5) for non-NRTI (NNRTI), and 2.2% (CI: 1.4-3.5) for protease inhibitors. A significant parabolic trend of NNRTI-TDR was found (p = 0.019). Factors significantly associated with TDR in univariate analysis were male gender, Belgian origin, MSM, recent infection, transmission clusters and subtype B, while multivariate and Bayesian network analysis singled out subtype B as the most predictive factor of TDR. Subtype B was related with transmission clusters with TDR that included 42.6% of the TDR patients. Thanks to resistance testing, 83% of the patients with TDR who started therapy had undetectable viral load whereas half of the patients would likely have received a suboptimal therapy without this test. In conclusion, TDR remained stable and a NNRTI up-and-down trend was observed. While the presence of clusters with TDR is worrying, we could not identify an independent, non-sequence based predictor for TDR or transmission clusters with TDR that could help with guidelines or public health measures.

  15. Clustered local transmission and asymptomatic Plasmodium falciparum and Plasmodium vivax malaria infections in a recently emerged, hypoendemic Peruvian Amazon community

    PubMed Central

    Branch, OraLee; Casapia, W Martin; Gamboa, Dionicia V; Hernandez, Jean N; Alava, Freddy F; Roncal, Norma; Alvarez, Eugenia; Perez, Enrique J; Gotuzzo, Eduardo

    2005-01-01

    Background There is a low incidence of malaria in Iquitos, Peru, suburbs detected by passive case-detection. This low incidence might be attributable to infections clustered in some households/regions and/or undetected asymptomatic infections. Methods Passive case-detection (PCD) during the malaria season (February-July) and an active case-detection (ACD) community-wide survey (March) surveyed 1,907 persons. Each month, April-July, 100-metre at-risk zones were defined by location of Plasmodium falciparum infections in the previous month. Longitudinal ACD and PCD (ACP+PCD) occurred within at-risk zones, where 137 houses (573 persons) were randomly selected as sentinels, each with one month of weekly active sampling. Entomological captures were conducted in the sentinel houses. Results The PCD incidence was 0.03 P. falciparum and 0.22 Plasmodium vivax infections/person/malaria-season. However, the ACD+PCD prevalence was 0.13 and 0.39, respectively. One explanation for this 4.33 and 1.77-fold increase, respectively, was infection clustering within at-risk zones and contiguous households. Clustering makes PCD, generalized to the entire population, artificially low. Another attributable-factor was that only 41% and 24% of the P. falciparum and P. vivax infections were associated with fever and 80% of the asymptomatic infections had low-density or absent parasitaemias the following week. After accounting for asymptomatic infections, a 2.6-fold increase in ACD+PCD versus PCD was attributable to clustered transmission in at-risk zones. Conclusion Even in low transmission, there are frequent highly-clustered asymptomatic infections, making PCD an inadequate measure of incidence. These findings support a strategy of concentrating ACD and insecticide campaigns in houses adjacent to houses were malaria was detected one month prior. PMID:15975146

  16. Trends and Predictors of Transmitted Drug Resistance (TDR) and Clusters with TDR in a Local Belgian HIV-1 Epidemic

    PubMed Central

    Pineda-Peña, Andrea-Clemencia; Schrooten, Yoeri; Vinken, Lore; Ferreira, Fossie; Li, Guangdi; Trovão, Nídia Sequeira; Khouri, Ricardo; Derdelinckx, Inge; De Munter, Paul; Kücherer, Claudia; Kostrikis, Leondios G.; Nielsen, Claus; Littsola, Kirsi; Wensing, Annemarie; Stanojevic, Maja; Paredes, Roger; Balotta, Claudia; Albert, Jan; Boucher, Charles; Gomez-Lopez, Arley; Van Wijngaerden, Eric; Van Ranst, Marc; Vercauteren, Jurgen; Vandamme, Anne-Mieke; Van Laethem, Kristel

    2014-01-01

    We aimed to study epidemic trends and predictors for transmitted drug resistance (TDR) in our region, its clinical impact and its association with transmission clusters. We included 778 patients from the AIDS Reference Center in Leuven (Belgium) diagnosed from 1998 to 2012. Resistance testing was performed using population-based sequencing and TDR was estimated using the WHO-2009 surveillance list. Phylogenetic analysis was performed using maximum likelihood and Bayesian techniques. The cohort was predominantly Belgian (58.4%), men who have sex with men (MSM) (42.8%), and chronically infected (86.5%). The overall TDR prevalence was 9.6% (95% confidence interval (CI): 7.7–11.9), 6.5% (CI: 5.0–8.5) for nucleoside reverse transcriptase inhibitors (NRTI), 2.2% (CI: 1.4–3.5) for non-NRTI (NNRTI), and 2.2% (CI: 1.4–3.5) for protease inhibitors. A significant parabolic trend of NNRTI-TDR was found (p = 0.019). Factors significantly associated with TDR in univariate analysis were male gender, Belgian origin, MSM, recent infection, transmission clusters and subtype B, while multivariate and Bayesian network analysis singled out subtype B as the most predictive factor of TDR. Subtype B was related with transmission clusters with TDR that included 42.6% of the TDR patients. Thanks to resistance testing, 83% of the patients with TDR who started therapy had undetectable viral load whereas half of the patients would likely have received a suboptimal therapy without this test. In conclusion, TDR remained stable and a NNRTI up-and-down trend was observed. While the presence of clusters with TDR is worrying, we could not identify an independent, non-sequence based predictor for TDR or transmission clusters with TDR that could help with guidelines or public health measures. PMID:25003369

  17. Gene-Set Local Hierarchical Clustering (GSLHC)--A Gene Set-Based Approach for Characterizing Bioactive Compounds in Terms of Biological Functional Groups.

    PubMed

    Chung, Feng-Hsiang; Jin, Zhen-Hua; Hsu, Tzu-Ting; Hsu, Chueh-Lin; Liu, Hsueh-Chuan; Lee, Hoong-Chien

    2015-01-01

    Gene-set-based analysis (GSA), which uses the relative importance of functional gene-sets, or molecular signatures, as units for analysis of genome-wide gene expression data, has exhibited major advantages with respect to greater accuracy, robustness, and biological relevance, over individual gene analysis (IGA), which uses log-ratios of individual genes for analysis. Yet IGA remains the dominant mode of analysis of gene expression data. The Connectivity Map (CMap), an extensive database on genomic profiles of effects of drugs and small molecules and widely used for studies related to repurposed drug discovery, has been mostly employed in IGA mode. Here, we constructed a GSA-based version of CMap, Gene-Set Connectivity Map (GSCMap), in which all the genomic profiles in CMap are converted, using gene-sets from the Molecular Signatures Database, to functional profiles. We showed that GSCMap essentially eliminated cell-type dependence, a weakness of CMap in IGA mode, and yielded significantly better performance on sample clustering and drug-target association. As a first application of GSCMap we constructed the platform Gene-Set Local Hierarchical Clustering (GSLHC) for discovering insights on coordinated actions of biological functions and facilitating classification of heterogeneous subtypes on drug-driven responses. GSLHC was shown to tightly clustered drugs of known similar properties. We used GSLHC to identify the therapeutic properties and putative targets of 18 compounds of previously unknown characteristics listed in CMap, eight of which suggest anti-cancer activities. The GSLHC website http://cloudr.ncu.edu.tw/gslhc/ contains 1,857 local hierarchical clusters accessible by querying 555 of the 1,309 drugs and small molecules listed in CMap. We expect GSCMap and GSLHC to be widely useful in providing new insights in the biological effect of bioactive compounds, in drug repurposing, and in function-based classification of complex diseases.

  18. Is It Possible To Obtain Coupled Cluster Quality Energies at near Density Functional Theory Cost? Domain-Based Local Pair Natural Orbital Coupled Cluster vs Modern Density Functional Theory.

    PubMed

    Liakos, Dimitrios G; Neese, Frank

    2015-09-08

    The recently developed domain-based local pair natural orbital coupled cluster theory with single, double, and perturbative triple excitations (DLPNO-CCSD(T)) delivers results that are closely approaching those of the parent canonical coupled cluster method at a small fraction of the computational cost. A recent extended benchmark study established that, depending on the three main truncation thresholds, it is possible to approach the canonical CCSD(T) results within 1 kJ (default setting, TightPNO), 1 kcal/mol (default setting, NormalPNO), and 2-3 kcal (default setting, LoosePNO). Although thresholds for calculations with TightPNO are 2-4 times slower than those based on NormalPNO thresholds, they are still many orders of magnitude faster than canonical CCSD(T) calculations, even for small and medium sized molecules where there is little locality. The computational effort for the coupled cluster step scales nearly linearly with system size. Since, in many instances, the coupled cluster step in DLPNO-CCSD(T) is cheaper or at least not much more expensive than the preceding Hartree-Fock calculation, it is useful to compare the method against modern density functional theory (DFT), which requires an effort comparable to that of Hartree-Fock theory (at least if Hartree-Fock exchange is part of the functional definition). Double hybrid density functionals (DHDF's) even require a MP2-like step. The purpose of this article is to evaluate the cost vs accuracy ratio of DLPNO-CCSD(T) against modern DFT (including the PBE, B3LYP, M06-2X, B2PLYP, and B2GP-PLYP functionals and, where applicable, their van der Waals corrected counterparts). To eliminate any possible bias in favor of DLPNO-CCSD(T), we have chosen established benchmark sets that were specifically proposed for evaluating DFT functionals. It is demonstrated that DLPNO-CCSD(T) with any of the three default thresholds is more accurate than any of the DFT functionals. Furthermore, using the aug-cc-pVTZ basis set and

  19. [Applying local neural network and visible/near-infrared spectroscopy to estimating available nitrogen, phosphorus and potassium in soil].

    PubMed

    Wu, Qian; Yang, Yu-hong; Xu, Zhao-li; Jin, Yan; Guo, Yan; Lao, Cai-lian

    2014-08-01

    To establish the quantitative relationship between soil spectrum and the concentration of available nitrogen, phosphorus and potassium in soil, the critical procedures of a new analysis method were examined, involving spectral preprocessing, wavebands selection and adoption of regression methods. As a result, a soil spectral analysis model was built using VIS/NIRS bands, with multiplicative scatter correction and first-derivative for spectral preprocessing, and local nonlinear regression method (Local regression method of BP neural network). The coefficients of correlation between the chemically determined and the modeled available nitrogen, phosphorus and potassium for predicted samples were 0.90, 0.82 and 0.94, respectively. It is proved that the prediction of local regression method of BP neural network has better accuracy and stability than that of global regression methods. In addition, the estimation accuracy of soil available nitrogen, phosphorus and potassium was increased by 40.63%, 28.64% and 28.64%, respectively. Thus, the quantitative analysis model established by the local regression method of BP neural network could be used to estimate the concentration of available nitrogen, phosphorus and potassium rapidly. It is innovative for using local nonlinear method to improve the stability and reliability of the soil spectrum model for nutrient diagnosis, which provides technical support for dynamic monitoring and process control for the soil nutrient under different growth stages of field-growing crops.

  20. Graph clustering techniques applied to the glycomic response in glioblastoma cells to treatments with STAT3 phosphorylation inhibition and fetal bovine serum

    NASA Astrophysics Data System (ADS)

    Görke, Robert; Meyer-Bäse, Anke; Plant, Claudia; He, Huan; Emmett, Mark R.; Nilsson, Carol; Colman, Howard; Conrad, Charles A.

    2011-06-01

    Cancer stem cells (CSC) represent a very small percentage of the total tumor population however they pose a big challenge in treating cancer. Glycans play a key role in cancer therapeutics since overexpression of them depending on the glycan type can lead either to cell death or more invasive metastasis. Two major components, fetal bovine serum (FBS) and STAT3, are known to up- or down-regulate certain glycolipid or phospholipid compositions found in glioblastoma CSCs. The analysis and the understanding of the global interactional behavior of lipidomic networks remains a challenging task and can not be accomplished solely based on intuitive reasoning. The present contribution aims at applying graph clustering networks to analyze the functional aspects of certain activators or inhibitors at the molecular level in glioblastoma stem cells (GSCs). This research enhances our understanding of the differences in phenotype changes and determining the responses of glycans to certain treatments for the aggressive GSCs, and represents together with a quantitative phosphoproteomic study1 the most detailed systems biology study of GSCs differentiation known so far. Thus, these new paradigms are providing unique understanding of the mechanisms involved in GSC maintenance and tumorigenicity and are thus opening a new window to biomedical frontiers.

  1. Do left and right asymmetries of hemispheric preference interact with attention to predict local and global performance in applied tasks?

    PubMed

    Jackson, Chris J; Hobman, Elizabeth V; Jimmieson, Nerina L; Martin, Robin

    2012-01-01

    Many cognitive neuroscience studies show that the ability to attend to and identify global or local information is lateralised between the two hemispheres in the human brain; the left hemisphere is biased towards the local level, whereas the right hemisphere is biased towards the global level. Results of two studies show attention-focused people with a right ear preference (biased towards the left hemisphere) are better at local tasks, whereas people with a left ear preference (biased towards the right hemisphere) are better at more global tasks. In a third study we determined if right hemisphere-biased followers who attend to global stimuli are likely to have a stronger relationship between attention and globally based supervisor ratings of performance. Results provide evidence in support of this hypothesis. Our research supports our model and suggests that the interaction between attention and lateral preference is an important and novel predictor of work-related outcomes.

  2. Hausdorff clustering

    NASA Astrophysics Data System (ADS)

    Basalto, Nicolas; Bellotti, Roberto; de Carlo, Francesco; Facchi, Paolo; Pantaleo, Ester; Pascazio, Saverio

    2008-10-01

    A clustering algorithm based on the Hausdorff distance is analyzed and compared to the single, complete, and average linkage algorithms. The four clustering procedures are applied to a toy example and to the time series of financial data. The dendrograms are scrutinized and their features compared. The Hausdorff linkage relies on firm mathematical grounds and turns out to be very effective when one has to discriminate among complex structures.

  3. Satellite Power System (SPS). State and local regulations as applied to satellite power system microwave receiving antenna facilities

    NASA Technical Reports Server (NTRS)

    Kotin, A. D.

    1978-01-01

    State and local regulation of power plant construction and operation of solar power satellite (SPS) receiving stations is presented. Each receiving antenna station occupies a land area 100-200 km square, receives microwave transmissions from the solar power satellite, and converts them into electricity for transmission to the power grid. The long lead time associated with the SPS and the changing status of state and local regulation dictated emphasis on: generic classification of the types of regulation, and identification of regulatory vectors which affect rectenna facilities.

  4. NEXAFS study on the local structures of DLC thin films formed by Ar cluster ion beam assisted deposition

    NASA Astrophysics Data System (ADS)

    Kanda, Kazuhiro; Kitagawa, Teruyuki; Shimizugawa, Yutaka; Tsubakino, Harushige; Yamada, Isao; Matsui, Shinji

    2003-08-01

    Near-edge X-ray absorption fine structure (NEXAFS) spectra were measured for the optimization of synthesis conditions on the production of diamond-like carbon (DLC) thin films by the Ar gas cluster ion beam (GCIB) assisted deposition of fullerene. The sp2 contents of DLC films were estimated from the analysis of the peak corresponding to the transition of the excitation electron from a carbon 1s orbital to a π* orbital in the NEXAFS spectrum of the carbon K-edge over the excitation energy range 275-320 eV. Substrate temperature and Ar cluster ion acceleration voltage in the synthesis conditions of DLC films were optimized to make the sp2 content minimum.

  5. Contextual Explanations of Local Dependence in Item Clusters in a Large Scale Hands-On Science Performance Assessment.

    ERIC Educational Resources Information Center

    Ferrara, Steven; Huynh, Huynh; Michaels, Hillary

    1999-01-01

    Provides hypothesized explanations for local item dependence (LID) in a large-scale hands-on science performance assessment involving approximately 55,000 students each at grades 3, 5, and 8. Items that appear to elicit locally dependent responses require examinees to answer and explain their answers or to use given or generalized information to…

  6. New Candidate Ehb Stars in the Open Cluster NGC 6791: Looking Locally Into the Uv-Upturn Phenomenon

    NASA Astrophysics Data System (ADS)

    Buson, L. M.; Bertone, E.; Buzzoni, A.; Carraro, G.

    Relying on U and B imagery at the Italian Telescopio Nazionale Galileo (TNG), we report here the discovery of a sample of 13 new UV-bright post-HB candidate stars in the field of the Galactic open cluster NGC 6791. Owing to its super-solar metal content ([Fe/H] ≳ 0.2 dex) and estimated age (t ≳ 8 Gyr), this cluster represents the nearest and ideal stellar aggregate to match the distinctive properties of the evolved stellar populations possibly ruling the UV-upturn phenomenon in elliptical galaxies and bulges of spirals. Our ongoing spectroscopic follow-up of this unique UV-bright sample will allow us to assess -- once cluster membership of the candidates is properly checked -- the real nature (e.g., sdB, sdO, AGB-manqué or EHB stars) of these hot sources and their link with the ultraviolet excess emerging from low-mass, metal-rich evolutionary environments of external galaxies.

  7. Filling the Void: The Roles of a Local Applied Research Center and a Statewide Workforce Training Consortium

    ERIC Educational Resources Information Center

    Perniciaro, Richard C.; Nespoli, Lawrence A.; Anbarasan, Sivaraman

    2015-01-01

    This chapter describes the development of an applied research center at Atlantic Cape Community College and a statewide workforce training consortium run by the community college sector in New Jersey. Their contributions to the economic development mission of the colleges as well as their impact on the perception of community colleges by…

  8. 20 CFR 667.645 - What procedures apply to the appeals of non-designation of local areas?

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... Procedures, Complaints, and State Appeals Processes § 667.645 What procedures apply to the appeals of non... days after receipt of written notification of the denial from the State Board, and must be submitted by... must establish that it was not accorded procedural rights under the appeal process set forth in...

  9. Filling the Void: The Roles of a Local Applied Research Center and a Statewide Workforce Training Consortium

    ERIC Educational Resources Information Center

    Perniciaro, Richard C.; Nespoli, Lawrence A.; Anbarasan, Sivaraman

    2015-01-01

    This chapter describes the development of an applied research center at Atlantic Cape Community College and a statewide workforce training consortium run by the community college sector in New Jersey. Their contributions to the economic development mission of the colleges as well as their impact on the perception of community colleges by…

  10. Data Clustering

    NASA Astrophysics Data System (ADS)

    Wagstaff, Kiri L.

    2012-03-01

    particular application involves considerations of the kind of data being analyzed, algorithm runtime efficiency, and how much prior knowledge is available about the problem domain, which can dictate the nature of clusters sought. Fundamentally, the clustering method and its representations of clusters carries with it a definition of what a cluster is, and it is important that this be aligned with the analysis goals for the problem at hand. In this chapter, I emphasize this point by identifying for each algorithm the cluster representation as a model, m_j , even for algorithms that are not typically thought of as creating a “model.” This chapter surveys a basic collection of clustering methods useful to any practitioner who is interested in applying clustering to a new data set. The algorithms include k-means (Section 25.2), EM (Section 25.3), agglomerative (Section 25.4), and spectral (Section 25.5) clustering, with side mentions of variants such as kernel k-means and divisive clustering. The chapter also discusses each algorithm’s strengths and limitations and provides pointers to additional in-depth reading for each subject. Section 25.6 discusses methods for incorporating domain knowledge into the clustering process. This chapter concludes with a brief survey of interesting applications of clustering methods to astronomy data (Section 25.7). The chapter begins with k-means because it is both generally accessible and so widely used that understanding it can be considered a necessary prerequisite for further work in the field. EM can be viewed as a more sophisticated version of k-means that uses a generative model for each cluster and probabilistic item assignments. Agglomerative clustering is the most basic form of hierarchical clustering and provides a basis for further exploration of algorithms in that vein. Spectral clustering permits a departure from feature-vector-based clustering and can operate on data sets instead represented as affinity, or similarity

  11. Local Control Theory in Trajectory Surface Hopping Dynamics Applied to the Excited-State Proton Transfer of 4-Hydroxyacridine.

    PubMed

    Curchod, Basile F E; Penfold, Thomas J; Rothlisberger, Ursula; Tavernelli, Ivano

    2015-07-20

    The application of local control theory combined with nonadiabatic ab initio molecular dynamics to study the photoinduced intramolecular proton transfer reaction in 4-hydroxyacridine was investigated. All calculations were performed within the framework of linear-response time-dependent density functional theory. The computed pulses revealed important information about the underlying excited-state nuclear dynamics highlighting the involvement of collective vibrational modes that would normally be neglected in a study performed on model systems constrained to a subset of the full configuration space. This study emphasizes the strengths of local control theory for the design of pulses that can trigger chemical reactions associated with the population of a given molecular excited state. In addition, analysis of the generated pulses can help to shed new light on the photophysics and photochemistry of complex molecular systems. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Initial Evaluation of the Heat-Affected Zone, Local Embrittlement Phenomenon as it Applies to Nuclear Reactor Vessels

    SciTech Connect

    McCabe, D.E.

    1999-09-01

    The objective of this project was to determine if the local brittle zone (LBZ) problem, encountered in the testing of the heat-affected zone (HAZ) part of welds in offshore platform construction, can also be found in reactor pressure vessel (RPV) welds. Both structures have multipass welds and grain coarsening along the fusion line. Literature was obtained that described the metallurgical evidence and the type of research work performed on offshore structure welds.

  13. Visual Simultaneous Localization And Mapping (VSLAM) methods applied to indoor 3D topographical and radiological mapping in real-time

    NASA Astrophysics Data System (ADS)

    Hautot, Felix; Dubart, Philippe; Bacri, Charles-Olivier; Chagneau, Benjamin; Abou-Khalil, Roger

    2017-09-01

    New developments in the field of robotics and computer vision enables to merge sensors to allow fast realtime localization of radiological measurements in the space/volume with near-real time radioactive sources identification and characterization. These capabilities lead nuclear investigations to a more efficient way for operators' dosimetry evaluation, intervention scenarii and risks mitigation and simulations, such as accidents in unknown potentially contaminated areas or during dismantling operations

  14. Effect of gas-liquid-crystal transitions in oxygen clusters on electric and magnetic activity of localized states in In2O3-SrO ceramic

    NASA Astrophysics Data System (ADS)

    Okunev, V. D.; Szymczak, R.; Szymczak, H.; Aleshkevych, P.; Glot, A. B.; Bondarchuk, A. N.

    2015-10-01

    It has been shown that the overlap of tails of the density of states of the valence and conduction bands leads to the formation of a "negative" gap in the In2O3-SrO ceramic with disordered structure and oxygen clusters in nanovoids. Two types of magnetism are observed. One of them caused by the formation of (dangling bond + O- 2 center) complexes has been found in samples saturated with oxygen. The other is associated with the presence of dangling bonds in oxygen-depleted samples. At T < 90.18 K, when oxygen molecules fall from the walls of nanovoids, small liquid oxygen droplets are formed with the release of a large number of free dangling bonds resulting in the variation of magnetization and electrical conductivity of samples. The effects caused by magnetic phase transitions in clusters of crystal oxygen are manifested at T < 54.8 K. The variations of the resistance of samples in the interval T = 5-300 K correspond to Mott's law under the dependence of the local activation energy for electron hopping on the state of oxygen clusters.

  15. Fluid-structure interaction analysis applied to thermal barrier coated cooled rocket thrust chambers with subsequent local investigation of delamination phenomena

    NASA Astrophysics Data System (ADS)

    Kowollik, D. S. C.; Horst, P.; Haupt, M. C.

    2013-03-01

    The aim of this work is to investigate numerically thermal barrier coating (TBC) systems applied to realistic rocket thrust chamber conditions. A global full parametric three-dimensional (3D) modeling approach for cooled rocket thrust chambers is presented to be able to simulate the fluid-structure interaction (FSI) phenomena involved. In a subsequent analysis step, realistic mechanical and thermal boundary conditions are extracted from critical design regions of the global model and applied to a local finite element model (FEM) to analyze possible TBC delaminations by means of a Fracture Mechanics (FM) approach.

  16. Localized versus delocalized excitations just above the 3d threshold in krypton clusters studied by Auger electron spectroscopy.

    PubMed

    Tchaplyguine, M; Kivimäki, A; Peredkov, S; Sorensen, S L; Ohrwall, G; Schulz, J; Lundwall, M; Rander, T; Lindblad, A; Rosso, A; Svensson, S; Mårtensson, N; Björneholm, O

    2007-09-28

    We present Auger spectroscopy studies of large krypton clusters excited by soft x-ray photons with energies on and just above the 3d(52) ionization threshold. The deexcitation spectra contain new features as compared to the spectra measured both below and far above threshold. Possible origins of these extra features, which stay at constant kinetic energies, are discussed: (1) normal Auger process with a postcollision interaction induced energy shift, (2) recapture of photoelectrons into high Rydberg orbitals after Auger decay, and (3) excitation into the conduction band (or "internal" ionization) followed by Auger decay. The first two schemes are ruled out, hence internal ionization remains the most probable explanation.

  17. Adsorption of carbon monoxide on small aluminum oxide clusters: Role of the local atomic environment and charge state on the oxidation of the CO molecule

    SciTech Connect

    Ornelas-Lizcano, J. C.; Guirado-López, R. A.

    2015-03-28

    We present extensive density functional theory (DFT) calculations dedicated to analyze the adsorption behavior of CO molecules on small Al{sub x}O{sub y}{sup ±} clusters. Following the experimental results of Johnson et al. [J. Phys. Chem. A 112, 4732 (2008)], we consider structures having the bulk composition Al{sub 2}O{sub 3}, as well as smaller Al{sub 2}O{sub 2} and Al{sub 2}O units. Our electron affinity and total energy calculations are consistent with aluminum oxide clusters having two-dimensional rhombus-like structures. In addition, interconversion energy barriers between two- and one-dimensional atomic arrays are of the order of 1 eV, thus clearly defining the preferred isomers. Single CO adsorption on our charged Al{sub x}O{sub y}{sup ±} clusters exhibits, in general, spontaneous oxygen transfer events leading to the production of CO{sub 2} in line with the experimental data. However, CO can also bind to both Al and O atoms of the clusters forming aluminum oxide complexes with a CO{sub 2} subunit. The vibrational spectra of Al{sub x}O{sub y} + CO{sub 2} provides well defined finger prints that may allow the identification of specific isomers. The Al{sub x}O{sub y}{sup +} clusters are more reactive than the anionic species and the final Al{sub 2}O{sup +} + CO reaction can result in the production of atomic Al and carbon dioxide as observed from experiments. We underline the crucial role played by the local atomic environment, charge density distribution, and spin-multiplicity on the oxidation behavior of CO molecules. Finally, we analyze the importance of coadsorption and finite temperature effects by performing DFT Born-Oppenheimer molecular dynamics. Our calculations show that CO oxidation on Al{sub x}O{sub y}{sup +} clusters can be also promoted by the binding of additional CO species at 300 K, revealing the existence of fragmentation processes in line with the ones experimentally inferred.

  18. Protein-protein association and cellular localization of four essential gene products encoded by tellurite resistance-conferring cluster "ter" from pathogenic Escherichia coli.

    PubMed

    Valkovicova, Lenka; Vavrova, Silvia Minarikova; Mravec, Jozef; Grones, Jozef; Turna, Jan

    2013-12-01

    Gene cluster "ter" conferring high tellurite resistance has been identified in various pathogenic bacteria including Escherichia coli O157:H7. However, the precise mechanism as well as the molecular function of the respective gene products is unclear. Here we describe protein-protein association and localization analyses of four essential Ter proteins encoded by minimal resistance-conferring fragment (terBCDE) by means of recombinant expression. By using a two-plasmid complementation system we show that the overproduced single Ter proteins are not able to mediate tellurite resistance, but all Ter members play an irreplaceable role within the cluster. We identified several types of homotypic and heterotypic protein-protein associations among the Ter proteins by in vitro and in vivo pull-down assays and determined their cellular localization by cytosol/membrane fractionation. Our results strongly suggest that Ter proteins function involves their mutual association, which probably happens at the interface of the inner plasma membrane and the cytosol.

  19. Choosing the best child assessment instrument for a specific context: a methodology for engaging local experts applied in Chile.

    PubMed

    Arbour, Marycatherine; Murray, Kara A; Atwood, Sidney S; Murray, Megan; Angel Cordero Vega, Miguel

    2012-10-01

    Chile is considering expanding its system for early childhood development to include 5- to 7-year olds, but it has no consensus about how to identify at-risk children. This study facilitated a process for incorporating local priorities and best practices to choose a child assessment instrument. Using the priority-setting method of the Child Health and Nutrition Research Initiative (CHNRI), 21 Chilean experts defined and weighted ideal assessment instrument characteristics; 130 instruments were scored according to how closely they matched experts' ideal definitions. Instruments were ranked by score under different inclusion criteria. Experts weighted instrument quality highest (95 on 1-100 scale), followed by administration site (87), domains assessed (82), cost (80), administrator (76), Spanish version (75), time (75), and prior use in Chile (53). Experts agreed that an ideal instrument (1) would reliably assess language, socioemotional well-being, mental health, and parenting abilities, (2) could be administered at schools or home, and (3) could be administered by teachers or parents. No single instrument matched all Chilean priorities. Three instruments met 11 of 13 priorities (age; quality; administration at school, home, or waiting rooms; assess language and socioemotional domains; administered by teachers, parents, or psychologists; time ≤30 minutes). Including mental health or parenting abilities ranked instruments whose composite scores were 35% lower. Decisions about how to assess children at developmental risk should be informed by local context. The CHNRI method provided a useful process that made explicit mutually exclusive priorities, quantified trade-offs of different assessment strategies, and identified 3 of the instruments that best met local needs and priorities.

  20. Scedosporium prolificans Osteomyelitis in an Immunocompetent Child Treated with Voriconazole and Caspofungin, as Well as Locally Applied Polyhexamethylene Biguanide

    PubMed Central

    Steinbach, William J.; Schell, Wiley A.; Miller, Jackie L.; Perfect, John R.

    2003-01-01

    Scedosporium species are increasingly isolated from immunocompromised and immunocompetent patients. Unfortunately, Scedosporium infections are generally resistant to amphotericin B, and Scedosporium prolificans strains are particularly resistant to the antifungal agents now in use. We report here on an immunocompetent child with S. prolificans-associated osteomyelitis successfully treated with debridement, local irrigation with polyhexamethylene biguanide, and the systemic administration of voriconazole and caspofungin despite poor in vitro activity of voriconazole alone against the isolate. We also review the treatments and outcomes of 28 reported cases of osteomyelitis or septic arthritis caused by Scedosporium species in immunocompetent patients. PMID:12904435

  1. Localization of the {alpha}7 integrin gene (ITGA7) on human chromosome 12q13: Clustering of integrin and Hox genes implies parallel evolution of these gene families

    SciTech Connect

    Wang, W.; Wu, W.; Kaufman, S.J.

    1995-04-10

    Expression of the {alpha}7 integrin gene (ITGA7) is developmentally regulated during the formation of skeletal muscle. Increased levels of expression and production of isoforms containing different cytoplasmic and extracellular domains accompany myogenesis. To determine whether a single or multiple {alpha}7 gene(s) underlie the structural diversity in this alpha chain that accompanies development, we have examined the rat and human genomes by Southern blotting and in situ hybridization. Our results demonstrate that there is only one {alpha}7 gene in both the rat and the human genomes. In the human, ITGA7 is present on chromosome 12q13. Phylogenetic analysis of the integrin alpha chain sequences suggests that the early integrin genes evolved in two pathways to form the I-integrins and the non-I-integrins. The I-integrin alpha chains contain an additional sequence of approximately 180 amino acids and arose as a result of an early insertion into the non-I-gene. The I-chain subfamily further evolved by duplications within the same chromosome. The non-I-integrin alpha chain genes are localized in clusters on chromosomes 2, 12, and 17, and this closely coincides with the localization of the human homeobox gene clusters. Non-I-integrin alpha chain genes appear to have evolved in parallel and in proximity to the Hox clusters. Thus, the Hox genes that underlie the design of body structure and the Integrin genes that underlie informed cell-cell and cell-matrix interactions appear to have evolved in parallel and coordinate fashions. 52 refs., 5 figs., 2 tabs.

  2. Gene Cluster Statistics with Gene Families

    PubMed Central

    Durand, Dannie

    2009-01-01

    Identifying genomic regions that descended from a common ancestor is important for understanding the function and evolution of genomes. In distantly related genomes, clusters of homologous gene pairs are evidence of candidate homologous regions. Demonstrating the statistical significance of such “gene clusters” is an essential component of comparative genomic analyses. However, currently there are no practical statistical tests for gene clusters that model the influence of the number of homologs in each gene family on cluster significance. In this work, we demonstrate empirically that failure to incorporate gene family size in gene cluster statistics results in overestimation of significance, leading to incorrect conclusions. We further present novel analytical methods for estimating gene cluster significance that take gene family size into account. Our methods do not require complete genome data and are suitable for testing individual clusters found in local regions, such as contigs in an unfinished assembly. We consider pairs of regions drawn from the same genome (paralogous clusters), as well as regions drawn from two different genomes (orthologous clusters). Determining cluster significance under general models of gene family size is computationally intractable. By assuming that all gene families are of equal size, we obtain analytical expressions that allow fast approximation of cluster probabilities. We evaluate the accuracy of this approximation by comparing the resulting gene cluster probabilities with cluster probabilities obtained by simulating a realistic, power-law distributed model of gene family size, with parameters inferred from genomic data. Surprisingly, despite the simplicity of the underlying assumption, our method accurately approximates the true cluster probabilities. It slightly overestimates these probabilities, yielding a conservative test. We present additional simulation results indicating the best choice of parameter values for data

  3. Applying a Behavioral Model Framework for Disaster Recovery Research in Local Public Health Agencies: A Conceptual Approach.

    PubMed

    Walsh, Lauren; Garrity, Stephanie; Rutkow, Lainie; Thompson, Carol B; Strauss-Riggs, Kandra; Altman, Brian A; Schor, Kenneth; Barnett, Daniel J

    2015-08-01

    The local public health agency (LPHA) workforce is at the center of the public health emergency preparedness system and is integral to locally driven disaster recovery efforts. Throughout the disaster recovery period, LPHAs have a primary responsibility for community health and are responsible for a large number of health services. In the face of decreasing preparedness funding and increasing frequency and severity of disasters, LPHAs continue to provide essential disaster life cycle services to their communities. However, little is known about the confidence that LPHA workers have in performing disaster recovery-related duties. To date, there is no widely used instrument to measure LPHA workers' sense of efficacy, nor is there an educational intervention designed specifically to bolster disaster recovery-phase efficacy perceptions. Here, we describe the important role of the LPHA workforce in disaster recovery and the operational- and efficacy-related research gaps inherent in today's disaster recovery practices. We then propose a behavioral framework that can be used to examine LPHA workers' disaster recovery perceptions and suggest a research agenda to enhance LPHA workforce disaster recovery efficacy through an evidence-informed educational intervention.

  4. Accurate thermochemistry from a parameterized coupled-cluster singles and doubles model and a local pair natural orbital based implementation for applications to larger systems.

    PubMed

    Huntington, Lee M J; Hansen, Andreas; Neese, Frank; Nooijen, Marcel

    2012-02-14

    We have recently introduced a parameterized coupled-cluster singles and doubles model (pCCSD(α, β)) that consists of a bivariate parameterization of the CCSD equations and is inspired by the coupled electron pair approximations. In our previous work, it was demonstrated that the pCCSD(-1, 1) method is an improvement over CCSD for the calculation of geometries, harmonic frequencies, and potential energy surfaces for single bond-breaking. In this paper, we find suitable pCCSD parameters for applications in reaction thermochemistry and thermochemical kinetics. The motivation is to develop an accurate and economical methodology that, when coupled with a robust local correlation framework based on localized pair natural orbitals, is suitable for large-scale thermochemical applications for sizeable molecular systems. It is demonstrated that the original pCCSD(-1, 1) method and several other pCCSD methods are a significant improvement upon the standard CCSD approach and that these methods often approach the accuracy of CCSD(T) for the calculation of reaction energies and barrier heights. We also show that a local version of the pCCSD methodology, implemented within the local pair natural orbital (LPNO) based CCSD code in ORCA, is sufficiently accurate for wide-scale chemical applications. The LPNO based methodology allows us for routine applications to intermediate sized (20-100 atoms) molecular systems and is a significantly more accurate alternative to MP2 and density functional theory for the prediction of reaction energies and barrier heights.

  5. The SMART CLUSTER METHOD - adaptive earthquake cluster analysis and declustering

    NASA Astrophysics Data System (ADS)

    Schaefer, Andreas; Daniell, James; Wenzel, Friedemann

    2016-04-01

    Earthquake declustering is an essential part of almost any statistical analysis of spatial and temporal properties of seismic activity with usual applications comprising of probabilistic seismic hazard assessments (PSHAs) and earthquake prediction methods. The nature of earthquake clusters and subsequent declustering of earthquake catalogues plays a crucial role in determining the magnitude-dependent earthquake return period and its respective spatial variation. Various methods have been developed to address this issue from other researchers. These have differing ranges of complexity ranging from rather simple statistical window methods to complex epidemic models. This study introduces the smart cluster method (SCM), a new methodology to identify earthquake clusters, which uses an adaptive point process for spatio-temporal identification. Hereby, an adaptive search algorithm for data point clusters is adopted. It uses the earthquake density in the spatio-temporal neighbourhood of each event to adjust the search properties. The identified clusters are subsequently analysed to determine directional anisotropy, focussing on a strong correlation along the rupture plane and adjusts its search space with respect to directional properties. In the case of rapid subsequent ruptures like the 1992 Landers sequence or the 2010/2011 Darfield-Christchurch events, an adaptive classification procedure is applied to disassemble subsequent ruptures which may have been grouped into an individual cluster using near-field searches, support vector machines and temporal splitting. The steering parameters of the search behaviour are linked to local earthquake properties like magnitude of completeness, earthquake density and Gutenberg-Richter parameters. The method is capable of identifying and classifying earthquake clusters in space and time. It is tested and validated using earthquake data from California and New Zealand. As a result of the cluster identification process, each event in

  6. The interrealtionship between locally applied heat, ageing and skin blood flow on heat transfer into and from the skin.

    PubMed

    Petrofsky, Jerrold; Alshahmmari, Faris; Yim, Jong Eun; Hamdan, Adel; Lee, Haneul; Neupane, Sushma; Shetye, Gauri; Moniz, Harold; Chen, Wei-Ti; Cho, Sungkwan; Pathak, Kunal; Malthane, Swapnil; Shenoy, Samruddha; Somanaboina, Karunakar; Alshaharani, Mastour; Nevgi, Bhakti; Dave, Bhargav; Desai, Rajavi

    2011-07-01

    In response to a thermal stress, skin blood flow (BF) increases to protect the skin from damage. When a very warm, noxious, heat source (44 °C) is applied to the skin, the BF increases disproportionately faster than the heat stress that was applied, creating a safety mechanism for protecting the skin. In the present investigation, the rate of rise of BF in response to applied heat at temperatures between 32 °C and 40 °C was examined as well as the thermal transfer to and from the skin with and without BF in younger and older subjects to see how the skin responds to a non-noxious heat source. Twenty male and female subjects (10 - 20-35 years, 10 - 40-70 years) were examined. The arms of the subjects were passively heated for 6 min with and without vascular occlusion by a thermode at temperatures of 32, 36, 38 or 40 °C. When occlusion was not used during the 6 min exposure to heat, there was an exponential rise in skin temperature and BF in both groups of subjects over the 6-min period. However, the older subjects achieved similar skin temperatures but with the expenditure of fewer calories from the thermode than was seen for the younger subjects (p<0.05). BF was significantly less in the older group than the younger group at rest and after exposure to each of the three warmest thermode temperatures (p<0.05). As was seen for noxious temperatures, after a delay, the rate of rise of BF at the three warmest thermode temperatures was faster than the rise in skin temperature in the younger group but less in the older group of subjects. Thus, a consequence of ageing is reduced excess BF in response to thermal stress increasing susceptibility to thermal damage. This must be considered in modelling of BF.

  7. LCA of local strategies for energy recovery from waste in England, applied to a large municipal flow

    SciTech Connect

    Tunesi, Simonetta

    2011-03-15

    An intense waste management (WM) planning activity is currently undergoing in England to build the infrastructure necessary to treat residual wastes, increase recycling levels and the recovery of energy from waste. From the analyses of local WM strategic and planning documents we have identified the emerging of three different energy recovery strategies: established combustion of residual waste; pre-treatment of residual waste and energy recovery from Solid Recovered Fuel in a dedicated plant, usually assumed to be a gasifier; pre-treatment of residual waste and reliance on the market to accept the 'fuel from waste' so produced. Each energy recovery strategy will result in a different solution in terms of the technology selected; moreover, on the basis of the favoured solution, the total number, scale and location of thermal treatment plants built in England will dramatically change. To support the evaluation and comparison of these three WM strategy in terms of global environmental impacts, energy recovery possibilities and performance with respect to changing 'fuel from waste' market conditions, the LCA comparison of eight alternative WM scenarios for a real case study dealing with a large flow of municipal wastes was performed with the modelling tool WRATE. The large flow of waste modelled allowed to formulate and assess realistic alternative WM scenarios and to design infrastructural systems which are likely to correspond to those submitted for approval to the local authorities. The results show that all alternative scenarios contribute to saving abiotic resources and reducing global warming potential. Particularly relevant to the current English debate, the performance of a scenario was shown to depend not from the thermal treatment technology but from a combination of parameters, among which most relevant are the efficiency of energy recovery processes (both electricity and heat) and the calorific value of residual waste and pre-treated material. The

  8. LCA of local strategies for energy recovery from waste in England, applied to a large municipal flow.

    PubMed

    Tunesi, Simonetta

    2011-03-01

    An intense waste management (WM) planning activity is currently undergoing in England to build the infrastructure necessary to treat residual wastes, increase recycling levels and the recovery of energy from waste. From the analyses of local WM strategic and planning documents we have identified the emerging of three different energy recovery strategies: established combustion of residual waste; pre-treatment of residual waste and energy recovery from Solid Recovered Fuel in a dedicated plant, usually assumed to be a gasifier; pre-treatment of residual waste and reliance on the market to accept the 'fuel from waste' so produced. Each energy recovery strategy will result in a different solution in terms of the technology selected; moreover, on the basis of the favoured solution, the total number, scale and location of thermal treatment plants built in England will dramatically change. To support the evaluation and comparison of these three WM strategy in terms of global environmental impacts, energy recovery possibilities and performance with respect to changing 'fuel from waste' market conditions, the LCA comparison of eight alternative WM scenarios for a real case study dealing with a large flow of municipal wastes was performed with the modelling tool WRATE. The large flow of waste modelled allowed to formulate and assess realistic alternative WM scenarios and to design infrastructural systems which are likely to correspond to those submitted for approval to the local authorities. The results show that all alternative scenarios contribute to saving abiotic resources and reducing global warming potential. Particularly relevant to the current English debate, the performance of a scenario was shown to depend not from the thermal treatment technology but from a combination of parameters, among which most relevant are the efficiency of energy recovery processes (both electricity and heat) and the calorific value of residual waste and pre-treated material. The

  9. Applying an Ecohealth Perspective in a State of the Environment Report: Experiences of a Local Public Health Unit in Canada

    PubMed Central

    Lam, Steven; Leffley, Alanna; Cole, Donald C.

    2014-01-01

    We applied an Ecohealth perspective into a State of the Environment report for Grey Bruce Health Unit and summarized environmental and health data relevant for public health practice. We aimed for comprehensiveness in our data compilation, including: standard media categories (e.g., air, water, land); and ecological indicators (e.g., vectors, forests, wetlands). Data sources included both primary (collected by an organization) and secondary (assembled by others). We organized indicators with the Driving forces-Pressure-State-Exposure-Effect-Action (DPSEEA) framework created by the World Health Organization. Indicators of air, water and land quality generally appeared to point towards a healthy state. Vector-borne diseases remained low. Forests and wetlands appeared to be in good condition, however more monitoring data was needed to determine trends in their ecological indicators. Data were not available on biodiversity and fish conditions. The results of our application of the DPSEEA framework suggest that routinely collected environmental and health data can be structured into the framework, though challenges arose due to gaps in data availability, particularly for social and gender analyses. Ecohealth approaches had legitimacy with broader healthy community partners but applying such approaches was a complex undertaking. PMID:25546271

  10. The Detection of Clusters with Spatial Heterogeneity

    ERIC Educational Resources Information Center

    Zhang, Zuoyi

    2011-01-01

    This thesis consists of two parts. In Chapter 2, we focus on the spatial scan statistics with overdispersion and Chapter 3 is devoted to the randomized permutation test for identifying local patterns of spatial association. The spatial scan statistic has been widely used in spatial disease surveillance and spatial cluster detection. To apply it, a…

  11. The Detection of Clusters with Spatial Heterogeneity

    ERIC Educational Resources Information Center

    Zhang, Zuoyi

    2011-01-01

    This thesis consists of two parts. In Chapter 2, we focus on the spatial scan statistics with overdispersion and Chapter 3 is devoted to the randomized permutation test for identifying local patterns of spatial association. The spatial scan statistic has been widely used in spatial disease surveillance and spatial cluster detection. To apply it, a…

  12. AN OPTICAL CATALOG OF GALAXY CLUSTERS OBTAINED FROM AN ADAPTIVE MATCHED FILTER FINDER APPLIED TO SLOAN DIGITAL SKY SURVEY DATA RELEASE 6

    SciTech Connect

    Szabo, T.; Pierpaoli, E.; Pipino, A.; Dong, F.; Gunn, J. E-mail: pierpaol@usc.edu

    2011-07-20

    We present a new cluster catalog extracted from the Sloan Digital Sky Survey Data Release 6 (SDSS DR6) using an adaptive matched filter (AMF) cluster finder. We identify 69,173 galaxy clusters in the redshift range 0.045 {<=} z < 0.78 in 8420 deg{sup 2} of the sky. We provide angular position, redshift, richness, core, and virial radii estimates for these clusters, as well as an error analysis for each of these quantities. We also provide a catalog of more than 205,000 galaxies representing the three brightest galaxies in the r band which are possible brightest cluster galaxy (BCG) candidates. We show basic properties of the BCG candidates and study how their luminosity scales in redshift and cluster richness. We compare our catalog with the maxBCG and GMBCG catalogs, as well as with that of Wen et al. We match between 30% and 50% of clusters between catalogs over all overlapping redshift ranges. We find that the percentage of matches increases with the richness for all catalogs. We cross match the AMF catalog with available X-ray data in the same area of the sky and find 539 matches, 119 of which with temperature measurements. We present scaling relations between optical and X-ray properties and cluster center comparison. We find that both {Lambda}{sub 200} and R{sub 200} correlate well with both L{sub X} and T{sub X} , with no significant difference in trend if we restrict the matches to flux-limited X-ray samples.

  13. Effects of Locally Applied Glycerol and Xylitol on the Hydration, Barrier Function and Morphological Parameters of the Skin.

    PubMed

    Korponyai, Csilla; Szél, Edit; Behány, Zoltán; Varga, Erika; Mohos, Gábor; Dura, Ágnes; Dikstein, Shabtay; Kemény, Lajos; Erős, Gábor

    2017-02-08

    Glycerol and xylitol hydrate the skin and improve its barrier function over a short period. We studied the effects of glycerol and xylitol on the physiological properties and morphology of the skin after longer-term application. Twelve volunteers with dry skin were examined. Three areas on the arms were determined. Area 1 served as untreated control. The vehicle was applied to area 2, while area 3 was treated twice daily with a formulation containing glycerol (5%) and xylitol (5%) for 14 days. Transepidermal water loss (TEWL), hydration and biomechanical properties of the skin were monitored. Biopsies were taken for routine histology and immunohistochemistry for filaggrin and matrix metalloproteinase-1 (MMP-1). The polyols increased the skin hydration and protein quantity of filaggrin, elevated the interdigitation index, decreased the TEWL and improved the biomechanical properties of the skin, but did not change the protein expression of MMP-1. A combination of glycerol and xylitol can be useful additional therapy for dry skin.

  14. The Next Generation Virgo Cluster Survey. VII. The Intrinsic Shapes of Low-luminosity Galaxies in the Core of the Virgo Cluster, and a Comparison with the Local Group

    NASA Astrophysics Data System (ADS)

    Sánchez-Janssen, Rubén; Ferrarese, Laura; MacArthur, Lauren A.; Côté, Patrick; Blakeslee, John P.; Cuillandre, Jean-Charles; Duc, Pierre-Alain; Durrell, Patrick; Gwyn, Stephen; McConnacchie, Alan W.; Boselli, Alessandro; Courteau, Stéphane; Emsellem, Eric; Mei, Simona; Peng, Eric; Puzia, Thomas H.; Roediger, Joel; Simard, Luc; Boyer, Fred; Santos, Matthew

    2016-03-01

    We investigate the intrinsic shapes of low-luminosity galaxies in the central 300 kpc of the Virgo Cluster using deep imaging obtained as part of the Next Generation Virgo Cluster Survey (NGVS). We build a sample of nearly 300 red-sequence cluster members in the yet-unexplored -14 < Mg < -8 mag range, and we measure their apparent axis ratios, q, through Sérsic fits to their two-dimensional light distribution, which is well described by a constant ellipticity parameter. The resulting distribution of apparent axis ratios is then fit by families of triaxial models with normally distributed intrinsic ellipticities, E = 1 - C/A, and triaxialities, T = (A2 - B2)/(A2 - C2). We develop a Bayesian framework to explore the posterior distribution of the model parameters, which allows us to work directly on discrete data, and to account for individual, surface-brightness-dependent axis ratio uncertainties. For this population we infer a mean intrinsic ellipticity \\bar{E} = {0.43}-0.02+0.02 and a mean triaxiality \\bar{T} = {0.16}-0.06+0.07. This implies that faint Virgo galaxies are best described as a family of thick, nearly oblate spheroids with mean intrinsic axis ratios 1:0.94:0.57. The core of Virgo lacks highly elongated low-luminosity galaxies, with 95% of the population having q > 0.45. We additionally attempt a study of the intrinsic shapes of Local Group (LG) satellites of similar luminosities. For the LG population we infer a slightly larger mean intrinsic ellipticity \\bar{E} = {0.51}-0.06+0.07, and the paucity of objects with round apparent shapes translates into more triaxial mean shapes, 1:0.76:0.49. Numerical studies that follow the tidal evolution of satellites within LG-sized halos are in good agreement with the inferred shape distributions, but the mismatch for faint galaxies in Virgo highlights the need for more adequate simulations of this population in the cluster environment. We finally compare the intrinsic shapes of NGVS low-mass galaxies with

  15. Immunochemical Methods Applied to Art-Historical Materials: Identification and Localization of Proteins by ELISA and IFM.

    PubMed

    Cartechini, Laura; Palmieri, Melissa; Vagnini, Manuela; Pitzurra, Lucia

    2016-02-01

    Despite the large diffusion of natural organic substances in art-historical materials, their characterization presents many challenges due to the chemical complexity and instability with respect to degradation processes. Among natural products, proteins have been largely used in the past as binders but also as adhesives or additives in coating layers. Nevertheless, biological identification of proteins in art-historical objects is one of the most recent achievements obtained in heritage science thanks to the development of specifically tailored bio-analytical strategies. In the context of this active emerging discipline, immunological methods stand out for sensitivity, specificity and versatility for both protein recognition and localization in micro-samples. Furthermore, the growing use of immunological techniques for advanced diagnostics and clinical applications ensures continuous improvement in their analytical performance. Considering such, this review provides an overview of the most recent applications of enzyme linked immunosorbent assay and immunofluorescence microscopy techniques in the field of heritage materials. Specifically, the main strengths and potentials of the two techniques as well as their limits and drawbacks are presented and discussed herein.

  16. General second-order covariance of Gaussian maximum likelihood estimates applied to passive source localization in fluctuating waveguides.

    PubMed

    Bertsatos, Ioannis; Zanolin, Michele; Ratilal, Purnima; Chen, Tianrun; Makris, Nicholas C

    2010-11-01

    A method is provided for determining necessary conditions on sample size or signal to noise ratio (SNR) to obtain accurate parameter estimates from remote sensing measurements in fluctuating environments. These conditions are derived by expanding the bias and covariance of maximum likelihood estimates (MLEs) in inverse orders of sample size or SNR, where the first-order covariance term is the Cramer-Rao lower bound (CRLB). Necessary sample sizes or SNRs are determined by requiring that (i) the first-order bias and the second-order covariance are much smaller than the true parameter value and the CRLB, respectively, and (ii) the CRLB falls within desired error thresholds. An analytical expression is provided for the second-order covariance of MLEs obtained from general complex Gaussian data vectors, which can be used in many practical problems since (i) data distributions can often be assumed to be Gaussian by virtue of the central limit theorem, and (ii) it allows for both the mean and variance of the measurement to be functions of the estimation parameters. Here, conditions are derived to obtain accurate source localization estimates in a fluctuating ocean waveguide containing random internal waves, and the consequences of the loss of coherence on their accuracy are quantified.

  17. How Anion Chaotrope Changes the Local Structure of Water: Insights from Photoelectron Spectroscopy and Theoretical Modeling of SCN(-) Water Clusters.

    PubMed

    Valiev, Marat; Deng, Shihu H M; Wang, Xue-Bin

    2016-03-03

    The behavior of charged solute molecules in aqueous solutions is often classified using the concept of kosmotropes ("structure makers") and chaotropes ("structure breakers"). There is a growing consensus that the key to kosmotropic/chaotropic behaviors lies in the local solvent region, but the exact microscopic basis for such differentiation is not well-understood. This issue is examined in this work by analyzing size selective solvation of a well-known chaotrope, a negatively charged SCN(-) molecule. Combining experimental photoelectron spectroscopy measurements with theoretical modeling, we examine evolution of solvation structure up to eight waters. We observe that SCN(-) indeed fits the description of weakly hydrated ion, and its solvation is heavily driven by stabilization of water-water interaction network. However, the impact on water structure is more subtle than that associated with "structure breaker". In particular, we observe that the solvation structure of SCN(-) preserves the "packing" structure of the water network but changes local directionality of hydrogen bonds in the local solvent region. The resulting effect is closer to that of "structure weakener", where solute can be readily accommodated into the native water network, at the cost of compromising its stability due to constraints on hydrogen bonding directionality.

  18. Localization of the Bacillus subtilis murB gene within the dcw cluster is important for growth and sporulation.

    PubMed

    Real, Gonçalo; Henriques, Adriano O

    2006-03-01

    The Bacillus subtilis murB gene, encoding UDP-N-acetylenolpyruvoylglucosamine reductase, a key enzyme in the peptidoglycan (PG) biosynthetic pathway, is embedded in the dcw (for "division and cell wall") cluster immediately upstream of divIB. Previous attempts to inactivate murB were unsuccessful, suggesting its essentiality. Here we show that the cell morphology, growth rate, and resistance to cell wall-active antibiotics of murB conditional mutants is a function of the expression level of murB. In one mutant, in which murB was insertionally inactivated in a merodiploid bearing a second xylose-inducible PxylA-murB allele, DivIB levels were reduced and a normal growth rate was achieved only if MurB levels were threefold that of the wild-type strain. However, expression of an extra copy of divIB restored normal growth at wild-type levels of MurB. In contrast, DivIB levels were normal in a second mutant containing an in-frame deletion of murB (DeltamurB) in the presence of the PxylA-murB gene. Furthermore, this strain grew normally with wild-type levels of MurB. During sporulation, the levels of MurB were highest at the time of synthesis of the spore cortex PG. Interestingly, the DeltamurB PxylA-murB mutant did not sporulate efficiently even at high concentrations of inducer. Since high levels of inducer did not interfere with sporulation of a murB(+)PxylA-murB strain, it appears that ectopic expression of murB fails to support efficient sporulation. These data suggest that coordinate expression of divIB and murB is important for growth and sporulation. The genetic context of the murB gene within the dcw cluster is unique to the Bacillus group and, taken together with our data, suggests that in these species it contributes to the optimal expression of cell division and PG biosynthetic functions during both vegetative growth and spore development.

  19. Do local vasomotor effects elicit the motor deficits induced by intrathecally applied substance P antagonists in the rat?

    PubMed

    Barber, A; Wild, A; Wedel, R

    1987-09-23

    The intrathecal application of the substance P (SP) antagonists [D-Pro2,D-Trp7,9]SP (DPDT) and [D-Arg1, D-Pro2, D-Trp7,9, Leu11]SP (DAPTL) to the lumbar region of intact, freely moving rats produced laming of the hindlimbs at doses of 0.375 nmol and above, and 1.5 nmol and above, respectively. In addition, the administration of DPDT (doses of 25 and 0.18 nmol) and DAPTL (25 and 0.6 nmol) produced a powerful constriction of the dorsal median spinal vein (DMSV) in decerebrated, unanaesthetised rats. Intrathecal SP (25 or 1.0 nmol) had a similar action on the spinal circulation to DPDT and DAPTL, though laming was first observed at doses of 30 nmol and higher. This suggests that intrathecally applied SP antagonists do not elicit laming by causing an obstruction of the venous drainage of the spinal cord. Disturbances of the spinal circulation could, however, influence the results of behavioural or physiological experiments in which SP or its analogues are administered intrathecally.

  20. Lessons Learned From Implementing an Incident Command System During a Local Multiagency Response to a Legionnaires' Disease Cluster in Sydney, NSW.

    PubMed

    Quinn, Emma; Johnstone, Travers; Najjar, Zeina; Cains, Toni; Tan, Geoff; Huhtinen, Essi; Nilsson, Sven; Burgess, Stuart; Dunn, Matthew; Gupta, Leena

    2017-09-05

    The incident command system (ICS) provides a common structure to control and coordinate an emergency response, regardless of scale or predicted impact. The lessons learned from the application of an ICS for large infectious disease outbreaks are documented. However, there is scant evidence on the application of an ICS to manage a local multiagency response to a disease cluster with environmental health risks. The Sydney Local Health District Public Health Unit (PHU) in New South Wales, Australia, was notified of 5 cases of Legionnaires' disease during 2 weeks in May 2016. This unusual incident triggered a multiagency investigation involving an ICS with staff from the PHU, 3 local councils, and the state health department to help prevent any further public health risk. The early and judicious use of ICS enabled a timely and effective response by supporting clear communication lines between the incident controller and field staff. The field team was key in preventing any ongoing public health risk through inspection, sampling, testing, and management of water systems identified to be at-risk for transmission of legionella. Good working relationships between partner agencies and trust in the technical proficiency of environmental health staff aided in the effective management of the response. (Disaster Med Public Health Preparedness. 2017;page 1 of 4).

  1. Translational readthrough generates new astrocyte AQP4 isoforms that modulate supramolecular clustering, glial endfeet localization, and water transport.

    PubMed

    De Bellis, Manuela; Pisani, Francesco; Mola, Maria Grazia; Rosito, Stefania; Simone, Laura; Buccoliero, Cinzia; Trojano, Maria; Nicchia, Grazia Paola; Svelto, Maria; Frigeri, Antonio

    2017-05-01

    Regulation of water homeostasis is a central feature of central nervous system pathophysiology. In this context, several lines of evidence suggest a crucial role for the water channel aquaporin-4 (AQP4) and its plasma membrane supramolecular organization as the key element. Here, we demonstrate the expression in tissues of additional isoforms of AQP4 characterized by a C-terminal extension generated by programmed translational readthrough. These extended isoforms (AQP4ex) display a perivascular polarization and expression in dystrophin-dependent pools. AQP4ex reduces supramolecular clustering tendency and allows AQP4 interactions with syntrophin. Furthermore, site-directed mutagenesis of two serines in the extended C-terminus of AQP4ex showed potential regulation of water permeability by phosphorylation. Finally, AQP4ex expression can be positively modulated by gentamicin treatment, demonstrating the possibility of regulating the AQP4 translational readthrough frequency. This novel regulatory mechanism could have important pathophysiological implications for conditions in which alternations have been reported in AQP4 structure.

  2. The Use of Locally Applied Vibration to Minimize Pain during Fractional CO2 Laser Therapy in Living Liver-Donor Scar Management.

    PubMed

    Song, Sinyoung; Choi, Dong Hoon; Oh, Tae Suk

    2016-11-01

    Fractional CO2 laser is an effective treatment for scars, but most patients complain about sharp burning pain, even after the application of lidocaine ointment. This study analyzed the impact of a vibrating device to nonpharmacologically reduce the acute pain of laser treatment, in accordance with the gate control theory of pain management. This is a prospective study performed from May 2013 through March 2014. Fifty-three patients (mean age, 26.7 years; range, 16-44 years) who had donated livers for liver transplantation were treated with a fractional CO2 laser (10,600 nm; model eCO2, Lutronic Corp) for their abdomen scars. Laser treatment was applied 4 months after surgery. A commercially available, locally applied vibrating device (model UM-30M, Unix Electronics Co. Ltd.) was used, in an on-and-off pattern, together with the CO2 laser. A visual analogue scale (VAS; 0, no pain; 10, most severe pain) of pain sensation was assessed and statistically analyzed using a paired t-test. The average VAS score for pain with the vibrating device was 4.60 and the average VAS score without the vibrating device was 6.11. The average difference between scores was 1.51 (P=0.001). A locally applied vibrating device was demonstrated to be effective in reducing pain when treating with a fractional CO2 laser. Vibration treatment could be helpful when treating scars with fractional CO2 laser in pain-sensitive patients, particularly children.

  3. WINGS-SPE II: A catalog of stellar ages and star formation histories, stellar masses and dust extinction values for local clusters galaxies

    NASA Astrophysics Data System (ADS)

    Fritz, J.; Poggianti, B. M.; Cava, A.; Valentinuzzi, T.; Moretti, A.; Bettoni, D.; Bressan, A.; Couch, W. J.; D'Onofrio, M.; Dressler, A.; Fasano, G.; Kjærgaard, P.; Moles, M.; Omizzolo, A.; Varela, J.

    2011-02-01

    Context. The WIde-field Nearby Galaxy clusters Survey (wings) is a project whose primary goal is to study the galaxy populations in clusters in the local universe (z < 0.07) and of the influence of environment on their stellar populations. This survey has provided the astronomical community with a high quality set of photometric and spectroscopic data for 77 and 48 nearby galaxy clusters, respectively. Aims: In this paper we present the catalog containing the properties of galaxies observed by the wings SPEctroscopic (wings-spe) survey, which were derived using stellar populations synthesis modelling approach. We also check the consistency of our results with other data in the literature. Methods: Using a spectrophotometric model that reproduces the main features of observed spectra by summing the theoretical spectra of simple stellar populations of different ages, we derive the stellar masses, star formation histories, average age and dust attenuation of galaxies in our sample. Results: ~ 5300 spectra were analyzed with spectrophotometric techniques, and this allowed us to derive the star formation history, stellar masses and ages, and extinction for the wings spectroscopic sample that we present in this paper. Conclusions: The comparison with the total mass values of the same galaxies derived by other authors based on sdss data, confirms the reliability of the adopted methods and data. Based on observations taken at the Anglo Australian Telescope (3.9 m- AAT), and at the William Herschel Telescope (4.2 m- WHT).Full Table 2 is available in electronic form both at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/526/A45, and by querying the wings database at http://web.oapd.inaf.it/wings/new/index.html

  4. The Localized Discovery and Recovery for Query Packet Losses in Wireless Sensor Networks with Distributed Detector Clusters

    PubMed Central

    Teng, Rui; Leibnitz, Kenji; Miura, Ryu

    2013-01-01

    An essential application of wireless sensor networks is to successfully respond to user queries. Query packet losses occur in the query dissemination due to wireless communication problems such as interference, multipath fading, packet collisions, etc. The losses of query messages at sensor nodes result in the failure of sensor nodes reporting the requested data. Hence, the reliable and successful dissemination of query messages to sensor nodes is a non-trivial problem. The target of this paper is to enable highly successful query delivery to sensor nodes by localized and energy-efficient discovery, and recovery of query losses. We adopt local and collective cooperation among sensor nodes to increase the success rate of distributed discoveries and recoveries. To enable the scalability in the operations of discoveries and recoveries, we employ a distributed name resolution mechanism at each sensor node to allow sensor nodes to self-detect the correlated queries and query losses, and then efficiently locally respond to the query losses. We prove that the collective discovery of query losses has a high impact on the success of query dissemination and reveal that scalability can be achieved by using the proposed approach. We further study the novel features of the cooperation and competition in the collective recovery at PHY and MAC layers, and show that the appropriate number of detectors can achieve optimal successful recovery rate. We evaluate the proposed approach with both mathematical analyses and computer simulations. The proposed approach enables a high rate of successful delivery of query messages and it results in short route lengths to recover from query losses. The proposed approach is scalable and operates in a fully distributed manner. PMID:23748172

  5. The radial distribution of X-ray binaries and globular clusters in NGC 4649 and their relation with the local stellar mass density

    SciTech Connect

    Mineo, S.; Fabbiano, G.; D'Abrusco, R.; Fragos, T.; Kim, D.-W.; Strader, J.; Brodie, J. P.; Zezas, A.

    2014-01-10

    We investigate the radial distribution of the low-mass X-ray binary (LMXB) population in the elliptical galaxy NGC 4649, using Chandra and Hubble data to separate the field and globular cluster (GC) populations. GCs with LMXBs have the same radial distribution as the parent red and blue GCs. The radial profile of field LMXBs follows the V-band profile within the D25 of NGC 4649. Using the spatial information provided by our data, we find that the global galaxy-wide relations among cumulative number and luminosity of LMXBs and the integrated stellar mass hold on local scales within D25. An excess of field LMXBs with respect to the V-band light is observed in the galaxy's outskirts, which may be partially due to unidentified GC sources or to a rejuvenated field LMXB population caused by past merging interactions.

  6. Automated clustering of probe molecules from solvent mapping of protein surfaces: new algorithms applied to hot-spot mapping and structure-based drug design

    NASA Astrophysics Data System (ADS)

    Lerner, Michael G.; Meagher, Kristin L.; Carlson, Heather A.

    2008-10-01

    Use of solvent mapping, based on multiple-copy minimization (MCM) techniques, is common in structure-based drug discovery. The minima of small-molecule probes define locations for complementary interactions within a binding pocket. Here, we present improved methods for MCM. In particular, a Jarvis-Patrick (JP) method is outlined for grouping the final locations of minimized probes into physical clusters. This algorithm has been tested through a study of protein-protein interfaces, showing the process to be robust, deterministic, and fast in the mapping of protein "hot spots." Improvements in the initial placement of probe molecules are also described. A final application to HIV-1 protease shows how our automated technique can be used to partition data too complicated to analyze by hand. These new automated methods may be easily and quickly extended to other protein systems, and our clustering methodology may be readily incorporated into other clustering packages.

  7. IDENTIFICATION OF A MEMBRANE-LOCALIZED CYSTEINE CLUSTER NEAR THE SUBSTRATE BINDING SITES OF THE STREPTOCOCCUS EQUISIMILIS HYALURONAN SYNTHASE

    PubMed Central

    Kumari, Kshama; Weigel, Paul H.

    2005-01-01

    The membrane-bound hyaluronan synthase (HAS) from Streptococcus equisimilis (seHAS), which is the smallest Class I HAS, has four cysteine residues (positions 226, 262, 281, and 367) that are generally conserved within this family. Although Cys-null seHAS is still active, chemical modification of cysteine residues causes inhibition of wildtype enzyme (Kumari et al., J. Biol. Chem. 277, 13943, 2002). Here we studied the effects of N-ethylmaleimide (NEM) treatment on a panel of seHAS Cys-mutants to examine the structural and functional roles of the four cysteine residues in the activity of the enzyme. We found that Cys226, Cys262, and Cys281 are reactive with NEM, but that Cys367 is not. Substrate protection studies of wildtype seHAS and a variety of Cys-mutants revealed that binding of UDP-GlcUA, UDP-GlcNAc or UDP can protect Cys226 and Cys262 from NEM inhibition. Inhibition of the six double Cys-mutants of seHAS by sodium arsenite, which can crosslink vicinyl sulfhydryl groups, also supported the conclusion that Cys262 and Cys281 are close enough to be crosslinked. Similar results indicated that Cys281 and Cys367 are also very close in the active enzyme. We conclude that three of the four Cys residues in seHAS (Cys262, Cys281, and Cys367 ) are clustered very close together, that these Cys residues and Cys226 are located at the inner surface of the cell membrane, and that Cys226 and Cys262 are located in or near a UDP binding site. PMID:15616126

  8. Electron-beam-induced current measurements with applied bias provide insight to locally resolved acceptor concentrations at p-n junctions

    SciTech Connect

    Abou-Ras, D. Schäfer, N.; Baldaz, N.; Brunken, S.; Boit, C.

    2015-07-15

    Electron-beam-induced current (EBIC) measurements have been employed for the investigation of the local electrical properties existing at various types of electrical junctions during the past decades. In the standard configuration, the device under investigation is analyzed under short-circuit conditions. Further insight into the function of the electrical junction can be obtained when applying a bias voltage. The present work gives insight into how EBIC measurements at applied bias can be conducted at the submicrometer level, at the example of CuInSe{sub 2} solar cells. From the EBIC profiles acquired across ZnO/CdS/CuInSe{sub 2}/Mo stacks exhibiting p-n junctions with different net doping densities in the CuInSe{sub 2} layers, values for the width of the space-charge region, w, were extracted. For all net doping densities, these values decreased with increasing applied voltage. Assuming a linear relationship between w{sup 2} and the applied voltage, the resulting net doping densities agreed well with the ones obtained by means of capacitance-voltage measurements.

  9. Spatial clusters of suicide in Australia.

    PubMed

    Qi, Xin; Hu, Wenbiao; Page, Andrew; Tong, Shilu

    2012-07-23

    Understanding the spatial distribution of suicide can inform the planning, implementation and evaluation of suicide prevention activity. This study explored spatial clusters of suicide in Australia, and investigated likely socio-demographic determinants of these clusters. National suicide and population data at a statistical local area (SLA) level were obtained from the Australian Bureau of Statistics for the period of 1999 to 2003. Standardised mortality ratios (SMR) were calculated at the SLA level, and Geographic Information System (GIS) techniques were applied to investigate the geographical distribution of suicides and detect clusters of high risk in Australia. Male suicide incidence was relatively high in the northeast of Australia, and parts of the east coast, central and southeast inland, compared with the national average. Among the total male population and males aged 15 to 34, Mornington Shire had the whole or a part of primary high risk cluster for suicide, followed by the Bathurst-Melville area, one of the secondary clusters in the north coastal area of the Northern Territory. Other secondary clusters changed with the selection of cluster radius and age group. For males aged 35 to 54 years, only one cluster in the east of the country was identified. There was only one significant female suicide cluster near Melbourne while other SLAs had very few female suicide cases and were not identified as clusters. Male suicide clusters had a higher proportion of Indigenous population and lower median socio-economic index for area (SEIFA) than the national average, but their shapes changed with selection of maximum cluster radii setting. This study found high suicide risk clusters at the SLA level in Australia, which appeared to be associated with lower median socio-economic status and higher proportion of Indigenous population. Future suicide prevention programs should focus on these high risk areas.

  10. Comparing Chemistry to Outcome: The Development of a Chemical Distance Metric, Coupled with Clustering and Hierarchal Visualization Applied to Macromolecular Crystallography

    PubMed Central

    Bruno, Andrew E.; Ruby, Amanda M.; Luft, Joseph R.; Grant, Thomas D.; Seetharaman, Jayaraman; Montelione, Gaetano T.; Hunt, John F.; Snell, Edward H.

    2014-01-01

    Many bioscience fields employ high-throughput methods to screen multiple biochemical conditions. The analysis of these becomes tedious without a degree of automation. Crystallization, a rate limiting step in biological X-ray crystallography, is one of these fields. Screening of multiple potential crystallization conditions (cocktails) is the most effective method of probing a proteins phase diagram and guiding crystallization but the interpretation of results can be time-consuming. To aid this empirical approach a cocktail distance coefficient was developed to quantitatively compare macromolecule crystallization conditions and outcome. These coefficients were evaluated against an existing similarity metric developed for crystallization, the C6 metric, using both virtual crystallization screens and by comparison of two related 1,536-cocktail high-throughput crystallization screens. Hierarchical clustering was employed to visualize one of these screens and the crystallization results from an exopolyphosphatase-related protein from Bacteroides fragilis, (BfR192) overlaid on this clustering. This demonstrated a strong correlation between certain chemically related clusters and crystal lead conditions. While this analysis was not used to guide the initial crystallization optimization, it led to the re-evaluation of unexplained peaks in the electron density map of the protein and to the insertion and correct placement of sodium, potassium and phosphate atoms in the structure. With these in place, the resulting structure of the putative active site demonstrated features consistent with active sites of other phosphatases which are involved in binding the phosphoryl moieties of nucleotide triphosphates. The new distance coefficient, CDcoeff, appears to be robust in this application, and coupled with hierarchical clustering and the overlay of crystallization outcome, reveals information of biological relevance. While tested with a single example the potential applications

  11. Clus-DoC: a combined cluster detection and colocalization analysis for single-molecule localization microscopy data

    PubMed Central

    Pageon, Sophie V.; Nicovich, Philip R.; Mollazade, Mahdie; Tabarin, Thibault; Gaus, Katharina

    2016-01-01

    Advances in fluorescence microscopy are providing increasing evidence that the spatial organization of proteins in cell membranes may facilitate signal initiation and integration for appropriate cellular responses. Our understanding of how changes in spatial organization are linked to function has been hampered by the inability to directly measure signaling activity or protein association at the level of individual proteins in intact cells. Here we solve this measurement challenge by developing Clus-DoC, an analysis strategy that quantifies both the spatial distribution of a protein and its colocalization status. We apply this approach to the triggering of the T-cell receptor during T-cell activation, as well as to the functionality of focal adhesions in fibroblasts, thereby demonstrating an experimental and analytical workflow that can be used to quantify signaling activity and protein colocalization at the level of individual proteins. PMID:27582387

  12. Effects of locally applied nerve growth factor to the inferior alveolar nerve histology in a rabbit model of mandibular distraction osteogenesis.

    PubMed

    Wang, L; Zhao, Y; Cheng, X; Yang, Y; Liu, G; Ma, Q; Shang, H; Tian, L; Lei, D

    2009-01-01

    Distraction osteogenesis (DO) is widely used in deformities and defects of the craniofacial bone. Accelerating inferior alveolar nerve (IAN) recovery would aid the process. Nerve growth factor (NGF) plays a vital role in peripheral nerve regeneration. In this study, the ability of locally applied human NGF beta (hNGFbeta) to enhance the morphological recovery of the IAN in a rabbit model of mandibular DO was studied. Rabbits underwent bilateral DO with a rate of 0.5mm per 12h. Two doses of 40 microg hNGFbeta in buffer were injected into callus at the beginning the of consolidation time. The contralateral side received injections of placebo. Rabbits were killed at 14 and 28 days. IAN specimens were subjected to histological and histomorphometric analysis. In both 14 and 28 days consolidation experiments, nerve histological analysis showed less degeneration and more regeneration in nerve fibers on the hNGFbeta treated side than the control side. Histomorphometric analysis showed that the myelinated fiber density on the hNGFbeta treated side was significantly higher than on the control side (p<0.01). The data indicate that locally applied hNGFbeta can accelerate the morphological recovery of the IAN and may play a role in reducing nerve injury in mandibular DO clinically.

  13. Seismogenesis of clustered seismicity beneath the Kangra-Chamba sector of northwest Himalaya: Constraints from 3D local earthquake tomography

    NASA Astrophysics Data System (ADS)

    Kumar, Naresh; Arora, B. R.; Mukhopadhyay, Sagarika; Yadav, D. K.

    2013-01-01

    To investigate subsurface structure and seismogenic layers, 3D velocity inversion was carried out in the source zone of 1905 Kangra earthquake (M8.0) in the northwestern Himalaya. P-wave and S-wave phase data of 159 earthquakes recorded by a network of 21 stations were used for this purpose. Inverted velocity tomograms up to a depth range of 18 km show significant variations of 14% in Vp and Vs and 6% in the Vp/Vs across the major tectonic zones in the region. Synthesis of seismicity pattern, velocity structure, distinctive focal mechanisms coupled with nature of stress distribution allows mapping of three different source regions that control regional seismotectonics. Accumulating strains are partly consumed by sliding of Chamba Nappe to the southwest through reverse-fault movements along Chamba/Panjal/Main Boundary Thrusts. This coupled with normal-fault type displacements along Chenab Normal Fault in the north account for low magnitude widespread seismicity in upper 8-10 km of the crust. At intermediate depths from 8 to 15 km, adjusting to residual compressive stresses, the detachment or lower end of the MBT slips to produce thrust dominated seismicity. Nucleation of secondary stresses in local NE-SW oriented structure interacts in complex manner with regional stresses to generate normal type earthquakes below the plane of detachment and therefore three seismic regimes at different depths produce intense seismicity in a block of 30 × 30 km2 centered NE to the epicenter of Kangra earthquake.

  14. New SIMD Algorithms for Cluster Labeling on Parallel Computers

    NASA Astrophysics Data System (ADS)

    Apostolakis, John; Coddington, Paul; Marinari, Enzo

    Cluster algorithms are non-local Monte Carlo update schemes which can greatly increase the efficiency of computer simulations of spin models of magnets. The major computational task in these algorithms is connected component labeling, to identify clusters of connected sites on a lattice. We have devised some new SIMD component labeling algorithms, and implemented them on the Connection Machine. We investigate their performance when applied to the cluster update of the two-dimensional Ising spin model. These algorithms could also be applied to other problems which use connected component labeling, such as percolation and image analysis.

  15. Understanding the Role of Dispersion in Frustrated Lewis Pairs and Classical Lewis Adducts: A Domain-Based Local Pair Natural Orbital Coupled Cluster Study.

    PubMed

    Bistoni, Giovanni; Auer, Alexander A; Neese, Frank

    2017-01-18

    The interaction of Lewis acids and bases in both classical Lewis adducts and frustrated Lewis pairs (FLPs) is investigated to elucidate the role that London dispersion plays in different situations. The analysis comprises 14 different adducts between tris(pentafluorophenyl)borane and a series of phosphines, carbenes, and amines with various substituents, differing in both steric and electronic properties. The domain-based local pair natural orbital coupled-cluster (DLPNO-CCSD(T)) method is used in conjunction with the recently introduced local energy decomposition (LED) analysis to obtain state-of-the-art dissociation energies and, at the same time, a clear-cut definition of the London dispersion component of the interaction, with the ultimate goal of aiding in the development of designing principles for acid/base pairs with well-defined bonding features and reactivity. In agreement with previous DFT investigations, it is found that the London dispersion dominates the interaction energy in FLPs, and is also remarkably strong in Lewis adducts. In these latter systems, its magnitude can be easily modulated by modifying the polarizability of the substituents on the basic center, which is consistent with the recently introduced concept of dispersion energy donors. By counteracting the destabilizing energy contribution associated with the deformation of the monomers, the London dispersion drives the stability of many Lewis adducts.

  16. Cluster Morphology Analysis

    PubMed Central

    Jacquez, Geoffrey M.

    2009-01-01

    Most disease clustering methods assume specific shapes and do not evaluate statistical power using the applicable geography, at-risk population, and covariates. Cluster Morphology Analysis (CMA) conducts power analyses of alternative techniques assuming clusters of different relative risks and shapes. Results are ranked by statistical power and false positives, under the rationale that surveillance should (1) find true clusters while (2) avoiding false clusters. CMA then synthesizes results of the most powerful methods. CMA was evaluated in simulation studies and applied to pancreatic cancer mortality in Michigan, and finds clusters of flexible shape while routinely evaluating statistical power. PMID:20234799

  17. The Use of Locally Applied Vibration to Minimize Pain during Fractional CO2 Laser Therapy in Living Liver-Donor Scar Management

    PubMed Central

    Song, Sinyoung; Choi, Dong Hoon

    2016-01-01

    Background Fractional CO2 laser is an effective treatment for scars, but most patients complain about sharp burning pain, even after the application of lidocaine ointment. This study analyzed the impact of a vibrating device to nonpharmacologically reduce the acute pain of laser treatment, in accordance with the gate control theory of pain management. Methods This is a prospective study performed from May 2013 through March 2014. Fifty-three patients (mean age, 26.7 years; range, 16–44 years) who had donated livers for liver transplantation were treated with a fractional CO2 laser (10,600 nm; model eCO2, Lutronic Corp) for their abdomen scars. Laser treatment was applied 4 months after surgery. A commercially available, locally applied vibrating device (model UM-30M, Unix Electronics Co. Ltd.) was used, in an on-and-off pattern, together with the CO2 laser. A visual analogue scale (VAS; 0, no pain; 10, most severe pain) of pain sensation was assessed and statistically analyzed using a paired t-test. Results The average VAS score for pain with the vibrating device was 4.60 and the average VAS score without the vibrating device was 6.11. The average difference between scores was 1.51 (P=0.001). Conclusions A locally applied vibrating device was demonstrated to be effective in reducing pain when treating with a fractional CO2 laser. Vibration treatment could be helpful when treating scars with fractional CO2 laser in pain-sensitive patients, particularly children. PMID:27896190

  18. Analysis of the Effect of Locally Applied Inhomogeneous Static Magnetic Field-Exposure on Mouse Ear Edema – A Double Blind Study

    PubMed Central

    Kiss, Balázs; László, János F.; Szalai, Andrea; Pórszász, Róbert

    2015-01-01

    The effect static magnetic field (SMF)-exposure may exert on edema development has been investigated. A 6 h long whole-body (WBSMF) or local (LSMF), continuous, inhomogeneous SMF-exposure was applied on anesthetized mice in an in vivo model of mustard oil (MO)-induced ear edema. LSMF was applied below the treated ear, below the lumbar spine, or below the mandible. Ear thickness (v) was checked 8 times during the exposure period (at 0, 0.25, 1, 2, 3, 4, 5, and 6 h). The effect size of the applied treatment (η) on ear thickness was calculated by the formula η = 100% × (1–vj/vi), where group i is the control group and j is the treated group. Results showed that MO treatment in itself induced a significant ear edema with an effect of 9% (p<0.001). WBSMF or LSMF on the spine in combination with MO treatment increased ear thickness even further resulting in an effect of η>11% in both cases compared to SMF-exposure alone (p<0.001). In these cases SMF-exposure alone without MO treatment reduced ear thickness significantly (p<0.05), but within estimated experimental error. In cases of LSMF-exposure on the head, a significant SMF-exposure induced ear thickness reduction was found (η = 5%, p<0.05). LSMF-exposure on the spine affected ear thickness with and without MO treatment almost identically, which provides evidence that the place of local SMF action may be in the lower spinal region. PMID:25695832

  19. Mass spectrometry and photoelectron spectroscopy of tetracene cluster anions, (tetracene)n- (n = 1-100): evidence for the highly localized nature of polarization in a cluster analogue of oligoacene crystals.

    PubMed

    Mitsui, Masaaki; Ando, Naoto; Nakajima, Atsushi

    2007-10-04

    Photoelectron spectroscopy of tetracene cluster anions, (tetracene)n- (n = 1-100), reveals the coexistence of two types of isomers, designated as isomers I and II-1 (n = 10-50) or isomers I and II-2 (n > 60), in a wide size range. The vertical detachment energies (VDEs) of isomer I increase persistently due to polarization and structural relaxation effects, where a monomeric anion core is encompassed with geometrically reorganized neutral molecules. Conversely, a characteristic ion distribution in the mass spectrum of (tetracene)n-ensues from the two-dimensional (2D) herringbone-type ordering of isomer II-1, whose VDEs remain constant at 1.80 eV for n >/= 14. Also, isomer II-2, presumably adopting multilayered structural motifs, exhibits invariable VDEs of 2.0 eV, a manifestation of significant charge screening effects in these isomers. The invariable nature of the VDEs of isomers II-1 and II-2 unambiguously demonstrates a largely localized nature of polarization induced by the excess charge residing in microscopic crystal-like environments. Surprisingly, only 14 tetracene molecules within a 2D herringbone-type layer including an excess charge can provide the charge stabilization energy corresponding to approximately 80% of that of the crystal, and the rest of the energy is provided by polarization of neutral molecules in adjacent layers.

  20. Assessing complexity of skin blood flow oscillations in response to locally applied heating and pressure in rats: Implications for pressure ulcer risk

    NASA Astrophysics Data System (ADS)

    Liao, Fuyuan; O'Brien, William D.; Jan, Yih-Kuen

    2013-10-01

    The objective of this study was to investigate the effects of local heating on the complexity of skin blood flow oscillations (BFO) under prolonged surface pressure in rats. Eleven Sprague-Dawley rats were studied: 7 rats underwent surface pressure with local heating (△t=10 °C) and 4 rats underwent pressure without heating. A pressure of 700 mmHg was applied to the right trochanter area of rats for 3 h. Skin blood flow was measured using laser Doppler flowmetry. The loading period was divided into nonoverlapping 30 min epochs. For each epoch, multifractal detrended fluctuation analysis (MDFA) was utilized to compute DFA coefficients and complexity of endothelial related metabolic, neurogenic, and myogenic frequencies of BFO. The results showed that under surface pressure, local heating led to a significant decrease in DFA coefficients of myogenic frequency during the initial epoch of loading period, a sustained decrease in complexity of myogenic frequency, and a significantly higher degree of complexity of metabolic frequency during the later phase of loading period. Surrogate tests showed that the reduction in complexity of myogenic frequency was associated with a loss of nonlinearity whereas increased complexity of metabolic frequency was associated with enhanced nonlinearity. Our results indicate that increased metabolic activity and decreased myogenic response due to local heating manifest themselves not only in magnitudes of metabolic and myogenic frequencies but also in their structural complexity. This study demonstrates the feasibility of using complexity analysis of BFO to monitor the ischemic status of weight-bearing skin and risk of pressure ulcers.

  1. A cluster-randomized trial determining the efficacy of caterpillar cereal as a locally available and sustainable complementary food to prevent stunting and anaemia.

    PubMed

    Bauserman, Melissa; Lokangaka, Adrien; Gado, Justin; Close, Kelly; Wallace, Dennis; Kodondi, Kule-Koto; Tshefu, Antoinette; Bose, Carl

    2015-07-01

    We conducted a cluster-randomized controlled trial to assess the efficacy of a cereal made from caterpillars, a micronutrient-rich, locally available alternative animal-source food, on reducing stunting and anaemia in infants in the Democratic Republic of Congo. Six-month-old infants were cluster randomized to receive either caterpillar cereal daily until 18 months of age or the usual diet. At 18 months of age, anthropometric measurements and biological samples were collected. The rural Equateur Province in the Democratic Republic of Congo. One hundred and seventy-five infants followed from 6 to 18 months of age. Stunting was common at 6 months (35%) and the prevalence increased until 18 months (69%). There was no difference in stunting prevalence at 18 months between the intervention and control groups (67% v. 71%, P = 0.69). Infants in the cereal group had higher Hb concentration than infants in the control group (10.7 v. 10.1 g/dl, P = 0.03) and fewer were anaemic (26 v. 50%, P = 0.006), although there was no difference in estimates of body Fe stores (6.7 v. 7.2 mg/kg body weight, P = 0.44). Supplementation of complementary foods with caterpillar cereal did not reduce the prevalence of stunting at 18 months of age. However, infants who consumed caterpillar cereal had higher Hb concentration and fewer were anaemic, suggesting that caterpillar cereal might have some beneficial effect. The high prevalence of stunting at 6 months and the lack of response to this micronutrient-rich supplement suggest that factors other than dietary deficiencies also contribute to stunting.

  2. Cluster analysis of social and environment inequalities of infant mortality. A spatial study in small areas revealed by local disease mapping in France.

    PubMed

    Padilla, Cindy M; Deguen, Severine; Lalloue, Benoit; Blanchard, Olivier; Beaugard, Charles; Troude, Florence; Navier, Denis Zmirou; Vieira, Verónica M

    2013-06-01

    Mapping spatial distributions of disease occurrence can serve as a useful tool for identifying exposures of public health concern. Infant mortality is an important indicator of the health status of a population. Recent literature suggests that neighborhood deprivation status can modify the effect of air pollution on preterm delivery, a known risk factor for infant mortality. We investigated the effect of neighborhood social deprivation on the association between exposure to ambient air NO2 and infant mortality in the Lille and Lyon metropolitan areas, north and center of France, respectively, between 2002 and 2009. We conducted an ecological study using a neighborhood deprivation index estimated at the French census block from the 2006 census data. Infant mortality data were collected from local councils and geocoded using the address of residence. We generated maps using generalized additive models, smoothing on longitude and latitude while adjusting for covariates. We used permutation tests to examine the overall importance of location in the model and identify areas of increased and decreased risk. The average death rate was 4.2‰ and 4.6‰ live births for the Lille and Lyon metropolitan areas during the period. We found evidence of statistically significant precise clusters of elevated infant mortality for Lille and an east-west gradient of infant mortality risk for Lyon. Exposure to NO2 did not explain the spatial relationship. The Lille MA, socioeconomic deprivation index explained the spatial variation observed. These techniques provide evidence of clusters of significantly elevated infant mortality risk in relation with the neighborhood socioeconomic status. This method could be used for public policy management to determine priority areas for interventions. Moreover, taking into account the relationship between social and environmental exposure may help identify areas with cumulative inequalities.

  3. Cluster analysis of social and environment inequalities of infant mortality. A spatial study in small areas revealed by local disease mapping in France

    PubMed Central

    Padilla, Cindy M.; Deguen, Severine; Lalloue, Benoit; Blanchard, Olivier; Beaugard, Charles; Troude, Florence; Navier, Denis Zmirou; Vieira, Verónica M.

    2014-01-01

    Mapping spatial distributions of disease occurrence can serve as a useful tool for identifying exposures of public health concern. Infant mortality is an important indicator of the health status of a population. Recent literature suggests that neighborhood deprivation status can modify the effect of air pollution on preterm delivery, a known risk factor for infant mortality. We investigated the effect of neighborhood social deprivation on the association between exposure to ambient air NO2 and infant mortality in the Lille and Lyon metropolitan areas, north and center of France, respectively, between 2002 and 2009. We conducted an ecological study using a neighborhood deprivation index estimated at the French census block from the 2006 census data. Infant mortality data were collected from local councils and geocoded using the address of residence. We generated maps using generalized additive models, smoothing on longitude and latitude while adjusting for covariates. We used permutation tests to examine the overall importance of location in the model and identify areas of increased and decreased risk. The average death rate was 4.2‰ and 4.6‰ live births for the Lille and Lyon metropolitan areas during the period. We found evidence of statistically significant precise clusters of elevated infant mortality for Lille and an east-west gradient of infant mortality risk for Lyon. Exposure to NO2 did not explain the spatial relationship. The Lille MA, socioeconomic deprivation index explained the spatial variation observed. These techniques provide evidence of clusters of significantly elevated infant mortality risk in relation with the neighborhood socioeconomic status. This method could be used for public policy management to determine priority areas for interventions. Moreover, taking into account the relationship between social and environmental exposure may help identify areas with cumulative inequalities. PMID:23563257

  4. Analytic energy derivatives for the calculation of the first-order molecular properties using the domain-based local pair-natural orbital coupled-cluster theory

    NASA Astrophysics Data System (ADS)

    Datta, Dipayan; Kossmann, Simone; Neese, Frank

    2016-09-01

    The domain-based local pair-natural orbital coupled-cluster (DLPNO-CC) theory has recently emerged as an efficient and powerful quantum-chemical method for the calculation of energies of molecules comprised of several hundred atoms. It has been demonstrated that the DLPNO-CC approach attains the accuracy of a standard canonical coupled-cluster calculation to about 99.9% of the basis set correlation energy while realizing linear scaling of the computational cost with respect to system size. This is achieved by combining (a) localized occupied orbitals, (b) large virtual orbital correlation domains spanned by the projected atomic orbitals (PAOs), and (c) compaction of the virtual space through a truncated pair natural orbital (PNO) basis. In this paper, we report on the implementation of an analytic scheme for the calculation of the first derivatives of the DLPNO-CC energy for basis set independent perturbations within the singles and doubles approximation (DLPNO-CCSD) for closed-shell molecules. Perturbation-independent one-particle density matrices have been implemented in order to account for the response of the CC wave function to the external perturbation. Orbital-relaxation effects due to external perturbation are not taken into account in the current implementation. We investigate in detail the dependence of the computed first-order electrical properties (e.g., dipole moment) on the three major truncation parameters used in a DLPNO-CC calculation, namely, the natural orbital occupation number cutoff used for the construction of the PNOs, the weak electron-pair cutoff, and the domain size cutoff. No additional truncation parameter has been introduced for property calculation. We present benchmark calculations on dipole moments for a set of 10 molecules consisting of 20-40 atoms. We demonstrate that 98%-99% accuracy relative to the canonical CCSD results can be consistently achieved in these calculations. However, this comes with the price of tightening the

  5. Why we should not routinely apply irreversible electroporation as an alternative curative treatment modality for localized prostate cancer at this stage.

    PubMed

    Wendler, J J; Ganzer, R; Hadaschik, B; Blana, A; Henkel, T; Köhrmann, K U; Machtens, S; Roosen, A; Salomon, G; Sentker, L; Witzsch, U; Schlemmer, H P; Baumunk, D; Köllermann, J; Schostak, M; Liehr, U B

    2017-01-01

    Irreversible electroporation (IRE), a new tissue ablation procedure available since 2007, could meet the requirements for ideal focal therapy of prostate cancer with its postulated features, especially the absence of a thermal ablation effect. Thus far, there is not enough evidence of its effectiveness or adverse effects to justify its use as a definitive treatment option for localized prostate cancer. Moreover, neither optimal nor individual treatment parameters nor uniform endpoints have been defined thus far. No advantages over established treatment procedures have as yet been demonstrated. Nevertheless, IRE is now being increasingly applied for primary prostate cancer therapy outside clinical trials, not least through active advertising in the lay press. This review reflects the previous relevant literature on IRE of the prostate or prostate cancer and shows why we should not adopt IRE as a routine treatment modality at this stage.

  6. Local and long-range order and the influence of applied magnetic field on single-crystalline NiSb2O6

    NASA Astrophysics Data System (ADS)

    Christian, A. B.; Hunt, C. D.; Neumeier, J. J.

    2017-07-01

    The magnetic and thermal properties of single-crystalline NiSb2O6 are reported. The Ni2 + ions exhibit local magnetic order below ˜50 K followed by long-range antiferromagnetic order below TN=6.7 K. Analysis of the magnetic susceptibility data using the one-dimensional Heisenberg model with spin S =1 results in a magnetic exchange coupling J||/kB˜26.0 (1 ) K. TN is observed to either increase or decrease depending on whether field is applied perpendicular or parallel to the magnetic moment axis. A two-sublattice magnetic structure, with the axis of alignment alternating by 90 ∘ between neighboring layers along the crystallographic c axis, is argued to result in two magnetic transition temperatures for certain magnetic field directions, which agrees well with theory. This leads to a highly anisotropic magnetocaloric effect.

  7. A novel phase-unwrapping method based on pixel clustering and local surface fitting with application to Dixon water-fat MRI.

    PubMed

    Cheng, Junying; Mei, Yingjie; Liu, Biaoshui; Guan, Jijing; Liu, Xiaoyun; Wu, Ed X; Feng, Qianjin; Chen, Wufan; Feng, Yanqiu

    2017-03-01

    To develop and evaluate a novel 2D phase-unwrapping method that works robustly in the presence of severe noise, rapid phase changes, and disconnected regions. The MR phase map usually varies rapidly in regions adjacent to wraps. In contrast, the phasors can vary slowly, especially in regions distant from tissue boundaries. Based on this observation, this paper develops a phase-unwrapping method by using a pixel clustering and local surface fitting (CLOSE) approach to exploit different local variation characteristics between the phase and phasor data. The CLOSE approach classifies pixels into easy-to-unwrap blocks and difficult-to-unwrap residual pixels first, and then sequentially performs intrablock, interblock, and residual-pixel phase unwrapping by a region-growing surface-fitting method. The CLOSE method was evaluated on simulation and in vivo water-fat Dixon data, and was compared with phase region expanding labeler for unwrapping discrete estimates (PRELUDE). In the simulation experiment, the mean error ratio by CLOSE was less than 1.50%, even in areas with signal-to-noise ratio equal to 0.5, phase changes larger than π, and disconnected regions. For 350 in vivo knee and ankle images, the water-fat swap ratio of CLOSE was 4.29%, whereas that of PRELUDE was 25.71%. The CLOSE approach can correctly unwrap phase with high robustness, and benefit MRI applications that require phase unwrapping. Magn Reson Med, 2017. © 2017 International Society for Magnetic Resonance in Medicine. © 2017 International Society for Magnetic Resonance in Medicine.

  8. Time frequency analysis of laser Doppler flowmetry signals recorded in response to a progressive pressure applied locally on anaesthetized healthy rats

    NASA Astrophysics Data System (ADS)

    Humeau, Anne; Koïtka, Audrey; Abraham, Pierre; Saumet, Jean-Louis; L'Huillier, Jean-Pierre

    2004-03-01

    The laser Doppler flowmetry technique has recently been used to report a significant transient increase of the cutaneous blood flow signal, in response to a local non-noxious pressure applied progressively on the skin of both healthy humans and rats. This phenomenon is not entirely understood yet. In the present work, a time-frequency analysis is applied to signals recorded on anaesthetized healthy rats, at rest and during a cutaneous pressure-induced vasodilation (PIV). The comparison, at rest and during PIV, of the scalogram relative energies and scalogram relative amplitudes in five bands, corresponding to five characteristic frequencies, shows an increased contribution for the endothelial related metabolic activity in PIV signals, till 400 s after the beginning of the progressive pressure application. The other subsystems (heart, respiration, myogenic and neurogenic activities) contribute relatively less during PIV than at rest. The differences are statistically significant for all the relative activities in the interval 0-200 s following the beginning of the pressure. These results and others obtained on patients, such as diabetics, could increase the understanding of some cutaneous pathologies involved in various neurological diseases and in the pathophysiology of decubitus ulcers.

  9. How Accurate Can a Local Coupled Cluster Approach Be in Computing the Activation Energies of Late-Transition