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Sample records for apply local clustering

  1. Fuzzy clustering of infrared images applied in air leak localization

    NASA Astrophysics Data System (ADS)

    Ge, Nan; Peng, Guang-zheng; Jiang, Mu-zhou

    2009-07-01

    Most current research into the localization of leaks is focused on leaks of petroleum and natural gas pipelines, while there is very little new work being done on the leakage of vessels. A novel air-leak diagnosis and localization method based on infrared thermography is described in this paper, which is developed in an attempt to overcome the disadvantages of low efficiency and poor anti-jamming ability associated with the traditional approaches to localization of leaks from a vessel. The method achieves leak positioning through a factor θ based kernelized fuzzy clustering segmentation done to weighted differential thermal images of the test objects. The temperature difference factor θ is inventively built as a parameter changed with temperature range of the target region, in order to enhance the robustness and the interference proof ability of the algorithm. Heat transfer simulation with air-leak flow is addressed by the finite element analysis. The experimental results indicate that the method proposed is effective and sensitive. The purpose of air-leak localization has been reached.

  2. 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.

  3. Local-density-driven clustered star formation

    NASA Astrophysics Data System (ADS)

    Parmentier, G.; Pfalzner, S.

    2013-01-01

    Context. A positive power-law trend between the local surface densities of molecular gas, Σgas, and young stellar objects, Σ ⋆ , in molecular clouds of the solar neighbourhood has recently been identified. How it relates to the properties of embedded clusters, in particular to the recently established radius-density relation, has so far not been investigated. Aims: We model the development of the stellar component of molecular clumps as a function of time and initial local volume density. Our study provides a coherent framework able to explain both the molecular-cloud and embedded-cluster relations quoted above. Methods: We associate the observed volume density gradient of molecular clumps to a density-dependent free-fall time. The molecular clump star formation history is obtained by applying a constant star formation efficiency per free-fall time, ɛff. Results: For the volume density profiles typical of observed molecular clumps (i.e. power-law slope ≃ -1.7), our model gives a star-gas surface-density relation of the form Σ⋆ ∝ Σgas2, which agrees very well with the observations. Taking the case of a molecular clump of mass M0 ≃ 104 M⊙ and radius R ≃ 6 pc experiencing star formation during 2 Myr, we derive what star formation efficiency per free-fall time matches the normalizations of the observed and predicted (Σ ⋆ , Σgas) relations best. We find ɛff ≃ 0.1. We show that the observed growth of embedded clusters, embodied by their radius-density relation, corresponds to a surface density threshold being applied to developing star-forming regions. The consequences of our model in terms of cluster survivability after residual star-forming gas expulsion are that, owing to the locally high star formation efficiency in the inner part of star-forming regions, global star formation efficiency as low as 10% can lead to the formation of bound gas-free star clusters.

  4. Cluster expansion for ground states of local Hamiltonians

    NASA Astrophysics Data System (ADS)

    Bastianello, Alvise; Sotiriadis, Spyros

    2016-08-01

    A central problem in many-body quantum physics is the determination of the ground state of a thermodynamically large physical system. We construct a cluster expansion for ground states of local Hamiltonians, which naturally incorporates physical requirements inherited by locality as conditions on its cluster amplitudes. Applying a diagrammatic technique we derive the relation of these amplitudes to thermodynamic quantities and local observables. Moreover we derive a set of functional equations that determine the cluster amplitudes for a general Hamiltonian, verify the consistency with perturbation theory and discuss non-perturbative approaches. Lastly we verify the persistence of locality features of the cluster expansion under unitary evolution with a local Hamiltonian and provide applications to out-of-equilibrium problems: a simplified proof of equilibration to the GGE and a cumulant expansion for the statistics of work, for an interacting-to-free quantum quench.

  5. 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. PMID:10487350

  6. 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.

  7. 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.

  8. A WISE VIEW OF STAR FORMATION IN LOCAL GALAXY CLUSTERS

    SciTech Connect

    Chung, Sun Mi; Gonzalez, Anthony H.; Eisenhardt, Peter R.; Stern, Daniel; Stanford, Spencer A.; Brodwin, Mark; Jarrett, Thomas

    2011-12-10

    We present results from a systematic study of star formation in local galaxy clusters using 22 {mu}m data from the Wide-field Infrared Survey Explorer (WISE). The 69 systems in our sample are drawn from the Cluster Infall Regions Survey, and all have robust mass determinations. The all-sky WISE data enable us to quantify the amount of star formation, as traced by 22 {mu}m, as a function of radius well beyond R{sub 200}, and investigate the dependence of total star formation rate upon cluster mass. We find that the fraction of star-forming galaxies increases with cluster radius but remains below the field value even at 3R{sub 200}. We also find that there is no strong correlation between the mass-normalized total specific star formation rate and cluster mass, indicating that the mass of the host cluster does not strongly influence the total star formation rate of cluster members.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. Applying cluster analysis to physics education research data

    NASA Astrophysics Data System (ADS)

    Springuel, R. Padraic

    One major thrust of Physics Education Research (PER) is the identification of student ideas about specific physics concepts, both correct ideas and those that differ from the expert consensus. Typically the research process of eliciting the spectrum of student ideas involves the administration of specially designed questions to students. One major analysis task in PER is the sorting of these student responses into thematically coherent groups. This process is one which has previously been done by eye in PER. This thesis explores the possibility of using cluster analysis to perform the task in a more rigorous and less time-intensive fashion while making fewer assumptions about what the students are doing. Since this technique has not previously been used in PER, a summary of the various kinds of cluster analysis is included as well as a discussion of which might be appropriate for the task of sorting student responses into groups. Two example data sets (one based on the Force and Motion Conceptual Evaluation (DICE) the other looking at acceleration in two-dimensions (A2D) are examined in depth to demonstrate how cluster analysis can be applied to PER data and the various considerations which must be taken into account when doing so. In both cases, the techniques described in this thesis found 5 groups which contained about 90% of the students in the data set. The results of this application are compared to previous research on the topics covered by the two examples to demonstrate that cluster analysis can effectively uncover the same patterns in student responses that have already been identified.

  14. Measles and Rubella: Scale Free Distribution of Local Infection Clusters.

    PubMed

    Yoshikura, Hiroshi; Takeuchi, Fumihiko

    2016-07-22

    This study examined the size distribution of local infection clusters (referred to as clusters hereafter) of measles and rubella from 2008-2013 in Japan. When the logarithm of the cluster sizes were plotted on the x-axis and the logarithm of their frequencies were plotted on the y-axis, the plots fell on a rightward descending straight line. The size distribution was observed to follow a power law. As the size distribution of the clusters could be equated with that of local secondary infections initiated by 1 patient, the size distribution of the clusters, in fact, represented the effective reproduction numbers at the local level. As the power law distribution has no typical sizes, it was suggested that measles or rubella epidemics in Japan had no typical reproduction number. Higher the population size and higher the total number of patients, flatter was the slope of the plots, thus larger was the proportion of larger clusters. An epidemic of measles or rubella in Japan could be represented more appropriately by the cluster size frequency distribution rather than by the reproduction number. PMID:26567836

  15. Locally Renormalized Coupled-Cluster Equations for Singly and Doubly Excited Clusters

    SciTech Connect

    Kowalski, Karol

    2006-07-10

    The Numerator-Denominator Connected (NDC) Expansion for the Coupled-Cluster (CC) method [K. Kowalski, P. Piecuch, J. Chem. Phys. 122 (2005) 074107], is used to construct a new set of stationary conditions for approximate coupled-cluster approaches. Several CC approximations based on models involving singles and doubles (CCSD) as well as singles, doubles, and triples (CCSDT) are developed and discussed in the context of ground-state applications. The resulting locally-renormalized CCSD (LR-CCSD) and CCSDT (LR-CCSDT) equations are shown to regularize the expressions for the cluster amplitudes in the challenging situations that occur when the orbital energy differences approach zero. Affordable schemes for handling the local denominators (all-holes-Jn coupling), that naturally appear in locally renormalized formalisms, are also discussed.

  16. 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. PMID:27421419

  17. 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.

  18. Are Young Massive Star Clusters in the Local Universe Analogous to Globular Clusters Progenitors?

    NASA Astrophysics Data System (ADS)

    Charbonnel, Corinne

    2015-08-01

    Several models do compete to reproduce the present-day characteristics of globular clusters (GC) and to explain the origin of the multiple stellar populations these systems are hosting.In parallel, independent clues on GC early evolution may be derived from observations of young massive clusters (YMC) in the Local Group.But are these two populations of clusters related? In this talk, we discuss how and if GC and YMC data can be reconciled.We revisit in particular the impact of massive stars on the early evolution of massive star clusters, as well as the question of early gas expulsion.We propose several tests to probe whether the YMC we are observing today can be considered as the analogues of GC progenitors.

  19. 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

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

    PubMed Central

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

    2013-01-01

    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. PMID:23385464

  1. 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

  2. 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. PMID:26192667

  3. OCAAT: automated analysis of star cluster colour-magnitude diagrams for gauging the local distance scale

    NASA Astrophysics Data System (ADS)

    Perren, Gabriel I.; Vázquez, Ruben A.; Piatti, Andrés E.; Moitinho, André

    2014-05-01

    Star clusters are among the fundamental astrophysical objects used in setting the local distance scale. Despite its crucial importance, the accurate determination of the distances to the Magellanic Clouds (SMC/LMC) remains a fuzzy step in the cosmological distance ladder. The exquisite astrometry of the recently launched ESA Gaia mission is expected to deliver extremely accurate statistical parallaxes, and thus distances, to the SMC/LMC. However, an independent SMC/LMC distance determination via main sequence fitting of star clusters provides an important validation check point for the Gaia distances. This has been a valuable lesson learnt from the famous Hipparcos Pleiades distance discrepancy problem. Current observations will allow hundreds of LMC/SMC clusters to be analyzed in this light. Today, the most common approach for star cluster main sequence fitting is still by eye. The process is intrinsically subjective and affected by large uncertainties, especially when applied to poorly populated clusters. It is also, clearly, not an efficient route for addressing the analysis of hundreds, or thousands, of star clusters. These concerns, together with a new attitude towards advanced statistical techniques in astronomy and the availability of powerful computers, have led to the emergence of software packages designed for analyzing star cluster photometry. With a few rare exceptions, those packages are not publicly available. Here we present OCAAT (Open Cluster Automated Analysis Tool), a suite of publicly available open source tools that fully automatises cluster isochrone fitting. The code will be applied to a large set of hundreds of open clusters observed in the Washington system, located in the Milky Way and the Magellanic Clouds. This will allow us to generate an objective and homogeneous catalog of distances up to ~ 60 kpc along with its associated reddening, ages and metallicities and uncertainty estimates.

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

    SciTech Connect

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

    2015-03-28

    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.

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

    SciTech Connect

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

    2013-02-01

    A new approach is presented that allows the efficient localization and orientation of heavy-atom cluster compounds used in experimental phasing by a molecular replacement procedure. This permits the calculation of meaningful phases up to the highest resolution of the diffraction data. 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.

  6. Cluster analysis applied to CO₂ concentrations at a rural site.

    PubMed

    Pérez, Isidro A; Sánchez, M Luisa; García, M Ángeles; Ozores, Marta; Pardo, Nuria

    2015-02-01

    In rural environments, atmospheric CO2 is mainly controlled by natural processes such as respiration-photosynthesis or low atmosphere evolution. This paper considers atmospheric CO2 measurements obtained at a rural site during 2011 using the wavelength-scanned cavity ringdown spectroscopy technique and presents two clustering methods, the silhouette being calculated to evaluate procedure validity. In the first method, clusters were formed depending on the similarity of wind roses, with satisfactory silhouette values. An anticyclonic rotation of the wind direction was observed during the daily cycle and clusters were formed by consecutive directions following the mixing layer evolution. However, monthly roses revealed four quite different wind directions, mainly oriented in the E-W axis. Although CO2 was not used in this procedure, a successful link between clusters and CO2 was obtained. In the second procedure, clusters were formed by the similarity of CO2 histograms calculated in intervals of one or two ancillary variables, wind direction, time of day, or month. The influence of a nearby city, the daily evolution of the low atmosphere, and the growing season were highlighted. Finally, the usefulness of the method lies in its easy extension to other gases or variables. PMID:25300184

  7. Incorporating Adaptive Local Information Into Fuzzy Clustering for Image Segmentation.

    PubMed

    Liu, Guoying; Zhang, Yun; Wang, Aimin

    2015-11-01

    Fuzzy c-means (FCM) clustering with spatial constraints has attracted great attention in the field of image segmentation. However, most of the popular techniques fail to resolve misclassification problems due to the inaccuracy of their spatial models. This paper presents a new unsupervised FCM-based image segmentation method by paying closer attention to the selection of local information. In this method, region-level local information is incorporated into the fuzzy clustering procedure to adaptively control the range and strength of interactive pixels. First, a novel dissimilarity function is established by combining region-based and pixel-based distance functions together, in order to enhance the relationship between pixels which have similar local characteristics. Second, a novel prior probability function is developed by integrating the differences between neighboring regions into the mean template of the fuzzy membership function, which adaptively selects local spatial constraints by a tradeoff weight depending upon whether a pixel belongs to a homogeneous region or not. Through incorporating region-based information into the spatial constraints, the proposed method strengthens the interactions between pixels within the same region and prevents over smoothing across region boundaries. Experimental results over synthetic noise images, natural color images, and synthetic aperture radar images show that the proposed method achieves more accurate segmentation results, compared with five state-of-the-art image segmentation methods. PMID:26186787

  8. Six clustering algorithms applied to the WAIS-R: the problem of dissimilar cluster results.

    PubMed

    Fraboni, M; Cooper, D

    1989-11-01

    Clusterings of the Wechsler Adult Intelligence Scale-Revised subtests were obtained from the application of six hierarchical clustering methods (N = 113). These sets of clusters were compared for similarities using the Rand index. The calculated indices suggested similarities of cluster group membership between the Complete Linkage and Centroid methods; Complete Linkage and Ward's methods; Centroid and Ward's methods; and Single Linkage and Average Linkage Between Groups methods. Cautious use of single clustering methods is implied, though the authors suggest some advantages of knowing specific similarities and differences. If between-method comparisons consistently reveal similar cluster membership, a choice could be made from those algorithms that tend to produce similar partitions, thereby enhancing cluster interpretation. PMID:2613904

  9. Local-world and cluster-growing weighted networks with controllable clustering

    NASA Astrophysics Data System (ADS)

    Yang, Chun-Xia; Tang, Min-Xuan; Tang, Hai-Qiang; Deng, Qiang-Qiang

    2014-12-01

    We constructed an improved weighted network model by introducing local-world selection mechanism and triangle coupling mechanism based on the traditional BBV model. The model gives power-law distributions of degree, strength and edge weight and presents the linear relationship both between the degree and strength and between the degree and the clustering coefficient. Particularly, the model is equipped with an ability to accelerate the speed increase of strength exceeding that of degree. Besides, the model is more sound and efficient in tuning clustering coefficient than the original BBV model. Finally, based on our improved model, we analyze the virus spread process and find that reducing the size of local-world has a great inhibited effect on virus spread.

  10. 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

  11. 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. PMID:25782980

  12. 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

  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. Applying Superresolution Localization-Based Microscopy to Neurons

    PubMed Central

    ZHONG, HAINING

    2016-01-01

    Proper brain function requires the precise localization of proteins and signaling molecules on a nanometer scale. The examination of molecular organization at this scale has been difficult in part because it is beyond the reach of conventional, diffraction-limited light microscopy. The recently developed method of superresolution, localization-based fluorescent microscopy (LBM), such as photoactivated localization microscopy (PALM) and stochastic optical reconstruction microscopy (STORM), has demonstrated a resolving power at a 10 nm scale and is poised to become a vital tool in modern neuroscience research. Indeed, LBM has revealed previously unknown cellular architectures and organizational principles in neurons. Here, we discuss the principles of LBM, its current applications in neuroscience, and the challenges that must be met before its full potential is achieved. We also present the unpublished results of our own experiments to establish a sample preparation procedure for applying LBM to study brain tissue. PMID:25648102

  15. 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

  16. Representing clusters using a maximum common edge substructure algorithm applied to reduced graphs and molecular graphs.

    PubMed

    Gardiner, Eleanor J; Gillet, Valerie J; Willett, Peter; Cosgrove, David A

    2007-01-01

    Chemical databases are routinely clustered, with the aim of grouping molecules which share similar structural features. Ideally, medicinal chemists are then able to browse a few representatives of the cluster in order to interpret the shared activity of the cluster members. However, when molecules are clustered using fingerprints, it may be difficult to decipher the structural commonalities which are present. Here, we seek to represent a cluster by means of a maximum common substructure based on the shared functionality of the cluster members. Previously, we have used reduced graphs, where each node corresponds to a generalized functional group, as topological molecular descriptors for virtual screening. In this work, we precluster a database using any clustering method. We then represent the molecules in a cluster as reduced graphs. By repeated application of a maximum common edge substructure (MCES) algorithm, we obtain one or more reduced graph cluster representatives. The sparsity of the reduced graphs means that the MCES calculations can be performed in real time. The reduced graph cluster representatives are readily interpretable in terms of functional activity and can be mapped directly back to the molecules to which they correspond, giving the chemist a rapid means of assessing potential activities contained within the cluster. Clusters of interest are then subject to a detailed R-group analysis using the same iterated MCES algorithm applied to the molecular graphs. PMID:17309248

  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. On the Nature of Local Instabilities in Rotating Galactic Coronae and Cool Cores of Galaxy Clusters

    NASA Astrophysics Data System (ADS)

    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.

  19. Applying Clustering Techniques to Reduce Complexity in Automated Planning Domains

    NASA Astrophysics Data System (ADS)

    Dicken, Luke; Levine, John

    Automated Planning is a very active area of research within Artificial Intelligence. Broadly this discipline deals with the methods by which an agent can independently determine the action sequence required to successfully achieve a set of objectives. In this paper, we will present initial work outlining a new approach to planning based on Clustering techniques, in order to group states of the world together and use the fundamental structure of the world to lift out more abstract representations. We will show that this approach can limit the combinatorial explosion of a typical planning problem in a way that is much more intuitive and reusable than has previously been possible, and outline ways that this approach can be developed further.

  20. Medoidshift clustering applied to genomic bulk tumor data.

    PubMed

    Roman, Theodore; Xie, Lu; Schwartz, Russell

    2016-01-01

    Despite the enormous medical impact of cancers and intensive study of their biology, detailed characterization of tumor growth and development remains elusive. This difficulty occurs in large part because of enormous heterogeneity in the molecular mechanisms of cancer progression, both tumor-to-tumor and cell-to-cell in single tumors. Advances in genomic technologies, especially at the single-cell level, are improving the situation, but these approaches are held back by limitations of the biotechnologies for gathering genomic data from heterogeneous cell populations and the computational methods for making sense of those data. One popular way to gain the advantages of whole-genome methods without the cost of single-cell genomics has been the use of computational deconvolution (unmixing) methods to reconstruct clonal heterogeneity from bulk genomic data. These methods, too, are limited by the difficulty of inferring genomic profiles of rare or subtly varying clonal subpopulations from bulk data, a problem that can be computationally reduced to that of reconstructing the geometry of point clouds of tumor samples in a genome space. Here, we present a new method to improve that reconstruction by better identifying subspaces corresponding to tumors produced from mixtures of distinct combinations of clonal subpopulations. We develop a nonparametric clustering method based on medoidshift clustering for identifying subgroups of tumors expected to correspond to distinct trajectories of evolutionary progression. We show on synthetic and real tumor copy-number data that this new method substantially improves our ability to resolve discrete tumor subgroups, a key step in the process of accurately deconvolving tumor genomic data and inferring clonal heterogeneity from bulk data. PMID:26817708

  1. Rat supraoptic neurones: the effects of locally applied hypertonic saline.

    PubMed

    Leng, G

    1980-07-01

    1. Extracellular action potentials were recorded from supraoptic neurones in lactating, urethane-anaesthetized rats. A microtap was used to apply a very small volume (about 10(-7) ml.) of hypertonic saline (1-4 M-NaCl) to the immediate neighbourhood of these units over about 1 min.2. Twenty-five of twenty-seven supraoptic neurones were excited by this local osmotic stimulus. The response of individual units was reversible and repeatable. Microtap applications of isotonic saline to supraoptic neurones were without observed effect.3. Continuously firing supraoptic neurones responded to hypertonic saline with a smooth acceleration in firing rate. Phasic neurones showed an increase in the over-all level of activity, and in particular, a prolongation of the active phases. Slow, irregularly firing cells responded either with a smooth acceleration in firing rate, or with phasic behaviour.4. The response to local hypertonic saline appears to be reasonably specific to the supraoptic nucleus. Of thirty-five neurones recorded close to the supraoptic nucleus but which were not antidromically activated from stimulation of the neural stalk, only nine responded to the local application of hypertonic saline.5. Similarities between the manner of response of supraoptic neurones to local application of hypertonic saline and the manner of their response to systemic increases in the osmotic pressure of blood plasma support the hypothesis that supraoptic neurones are osmosensitive. PMID:7441542

  2. 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.

  3. Local structural excitations in model glass systems under applied load

    NASA Astrophysics Data System (ADS)

    Swayamjyoti, S.; Löffler, J. F.; Derlet, P. M.

    2016-04-01

    The potential-energy landscape of a model binary Lennard-Jones structural glass is investigated as a function of applied external strain, in terms of how local structural excitations (LSEs) respond to the load. Using the activation relaxation technique and nudged elastic band methods, the evolving structure and barrier energy of such LSEs are studied in detail. For the case of a tensile/compressive strain, the LSE barrier energies generally decrease/increase, whereas under pure shear, it may either increase or decrease resulting in a broadening of the barrier energy distribution. It is found that how a particular LSE responds to an applied strain is strongly controlled by the LSE's far-field internal stress signature prior to loading.

  4. HST Search for Planetary Nebulae in Local Group Globular Clusters

    NASA Astrophysics Data System (ADS)

    Bond, Howard E.

    2015-01-01

    If every star of about solar mass produces a planetary nebula (PN) near the end of its life, there should be several dozen PNe in the globular clusters (GCs) of the Local Group. However, ground-based surveys of Milky Way GCs have revealed only 4 PNe. A converse argument is that it is likely that the remnants of stars now evolving in ancient GCs leave the AGB so slowly that any ejected PN dissipates long before the star becomes hot enough to ionize it. Thus there should not be any PNe in Milky Way GCs--but there are four! It has been suggested that these PNe are the result of binary mergers of binary stars within GCs, i.e., that they are descendants of blue stragglers. To explore these issues and extend them beyond the Milky Way, I carried out a Snapshot imaging survey of GCs throughout the Local Group with the Hubble Space Telescope. Observations were made with the WFPC2 camera in 2007-2008, and with WFC3 in 2009-2011. Frames were obtained in a narrow-band [O III] 5007 filter and in a broad V filter (F555W). In this filter combination, a PN will have a comparable signal in both bandpasses, but stars will be much brighter in the V filter. I surveyed 41 GCs in M31, 4 in M33, 8 in the Magellanic Clouds, 2 in Fornax, and 1 each in NGC 6822, WLM, and NGC 147. Only one candidate PN was found, in the M31 GC B086. My results appear to be consistent with a ground-based spectroscopic survey for PNe in the M31 GCs by Jacoby et al. (2013), which found only 3 PN candidates in 274 clusters. PNe are very rare in GCs, but a few do exist, and they may require binary interactions for their formation.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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

  10. Three-dimensional vasculature reconstruction of tumour microenvironment via local clustering and classification

    PubMed Central

    Zhu, Yanqiao; Li, Fuhai; Vadakkan, Tegy J.; Zhang, Mei; Landua, John; Wei, Wei; Ma, Jinwen; Dickinson, Mary E.; Rosen, Jeffrey M.; Lewis, Michael T.; Zhan, Ming; Wong, Stephen T. C.

    2013-01-01

    The vasculature inside breast cancers is one important component of the tumour microenvironment. The investigation of its spatial morphology, distribution and interactions with cancer cells, including cancer stem cells, is essential for elucidating mechanisms of tumour development and treatment response. Using confocal microscopy and fluorescent markers, we have acquired three-dimensional images of vasculature within mammary tumours and normal mammary gland of mouse models. However, it is difficult to segment and reconstruct complex vasculature accurately from the in vivo three-dimensional images owing to the existence of uneven intensity and regions with low signal-to-noise ratios (SNR). To overcome these challenges, we have developed a novel three-dimensional vasculature segmentation method based on local clustering and classification. First, images of vasculature are clustered into local regions, whose boundaries well delineate vasculature even in low SNR and uneven intensity regions. Then local regions belonging to vasculature are identified by applying a semi-supervised classification method based on three informative features of the local regions. Comparison of results using simulated and real vasculature images, from mouse mammary tumours and normal mammary gland, shows that the new method outperforms existing methods, and can be used for three-dimensional images with uneven background and low SNR to achieve accurate vasculature reconstruction. PMID:24511379

  11. Three-dimensional vasculature reconstruction of tumour microenvironment via local clustering and classification.

    PubMed

    Zhu, Yanqiao; Li, Fuhai; Vadakkan, Tegy J; Zhang, Mei; Landua, John; Wei, Wei; Ma, Jinwen; Dickinson, Mary E; Rosen, Jeffrey M; Lewis, Michael T; Zhan, Ming; Wong, Stephen T C

    2013-08-01

    The vasculature inside breast cancers is one important component of the tumour microenvironment. The investigation of its spatial morphology, distribution and interactions with cancer cells, including cancer stem cells, is essential for elucidating mechanisms of tumour development and treatment response. Using confocal microscopy and fluorescent markers, we have acquired three-dimensional images of vasculature within mammary tumours and normal mammary gland of mouse models. However, it is difficult to segment and reconstruct complex vasculature accurately from the in vivo three-dimensional images owing to the existence of uneven intensity and regions with low signal-to-noise ratios (SNR). To overcome these challenges, we have developed a novel three-dimensional vasculature segmentation method based on local clustering and classification. First, images of vasculature are clustered into local regions, whose boundaries well delineate vasculature even in low SNR and uneven intensity regions. Then local regions belonging to vasculature are identified by applying a semi-supervised classification method based on three informative features of the local regions. Comparison of results using simulated and real vasculature images, from mouse mammary tumours and normal mammary gland, shows that the new method outperforms existing methods, and can be used for three-dimensional images with uneven background and low SNR to achieve accurate vasculature reconstruction. PMID:24511379

  12. Testing spontaneous localization with ultra-massive cluster interferometry

    NASA Astrophysics Data System (ADS)

    Nimmrichter, Stefan; Hornberger, Klaus; Arndt, Markus

    2011-03-01

    Understanding the transition from the microscopic domain of quantum mechanics to our everyday classical world is still an open problem in modern physics. Collapse models are a possible way to resolve this issue by introducing mechanisms which break the quantum superposition principle above a certain mass and time scale. One of the best studied models is the theory of continuous spontaneous localization (CSL) by Ghirardi, Pearle and Rimini. We show that it should be possible to test the predictions of the CSL model in the new matter-wave interferometer for heavy metal clusters that is currently built in Vienna. Extending the original Talbot-Lau setup for biomolecules, the new scheme will operate in the time-domain using three pulsed standing-wave gratings of UV laser light. We argue that this should enable us to see single-particle interference in an unprecedented mass range from 105 up to even 108 atomic mass units. Recent estimates of the strength of the CSL effect by Adler and Bassi [2,3] suggest that a breakdown of the quantum superposition principle would occur in precisely this mass regime.

  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. PMID:16784337

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

    PubMed

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

    2014-01-01

    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. PMID:25479330

  15. A Local Energy Consumption Prediction-Based Clustering Protocol for Wireless Sensor Networks

    PubMed Central

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

    2014-01-01

    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. PMID:25479330

  16. 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

  17. THE DYNAMICS OF MERGING CLUSTERS: A MONTE CARLO SOLUTION APPLIED TO THE BULLET AND MUSKET BALL CLUSTERS

    SciTech Connect

    Dawson, William A.

    2013-08-01

    Merging galaxy clusters have become one of the most important probes of dark matter, providing evidence for dark matter over modified gravity and even constraints on the dark matter self-interaction cross-section. To properly constrain the dark matter cross-section it is necessary to understand the dynamics of the merger, as the inferred cross-section is a function of both the velocity of the collision and the observed time since collision. While the best understanding of merging system dynamics comes from N-body simulations, these are computationally intensive and often explore only a limited volume of the merger phase space allowed by observed parameter uncertainty. Simple analytic models exist but the assumptions of these methods invalidate their results near the collision time, plus error propagation of the highly correlated merger parameters is unfeasible. To address these weaknesses I develop a Monte Carlo method to discern the properties of dissociative mergers and propagate the uncertainty of the measured cluster parameters in an accurate and Bayesian manner. I introduce this method, verify it against an existing hydrodynamic N-body simulation, and apply it to two known dissociative mergers: 1ES 0657-558 (Bullet Cluster) and DLSCL J0916.2+2951 (Musket Ball Cluster). I find that this method surpasses existing analytic models-providing accurate (10% level) dynamic parameter and uncertainty estimates throughout the merger history. This, coupled with minimal required a priori information (subcluster mass, redshift, and projected separation) and relatively fast computation ({approx}6 CPU hours), makes this method ideal for large samples of dissociative merging clusters.

  18. Cluster analysis applied to velocity and attenuation tomography: the case study of Mt. Vesuvius

    NASA Astrophysics Data System (ADS)

    Siniscalchi, A.; Bianco, F.; Del Pezzo, E.; de Siena, L.; di Giuseppe, M. G.; Petrillo, Z.

    2009-04-01

    The interpretation of the results of seismic velocity and attenuation 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. The Vp velocity and Qp and Qs attenuation structures of Mt. Vesuvius, Italy, have been already qualitatively interpreted by a comparison with other similar investigations. To obtain a more quantitative interpretation gathered in a unified model consistent with the entire dataset, a cluster analysis was applied to this models. An optimizing study on the proper number of classes recognizes five clusters corresponding to separate zones inside the volcano structure. - The first cluster can be considered as a "background" cluster, and corresponds to the areas with "average" seismic properties (mainly located below the topographical interface). - The second cluster defines a spatial pattern corresponding to the residual part of the feeding conduit of the volcano. - The third cluster corresponds to two volumes, the first vertically extended between -1000 and -3000 m above the sea level, North-Eastward the cone; the second, in the same depth range Westward the central cone, and linked to the first one at -2000 m. These two volumes may be associated with hydrothermal basins. - The fourth and fifth clusters are described both by

  19. A Reference Sample of Local Rich Galaxy Clusters: Infrared Emission from Infalling Galaxies and DIffuse Intra-Cluster Dust

    NASA Astrophysics Data System (ADS)

    Fadda, Dario; Biviano, Andrea; Marleau, Francine; Storrie-Lombardi, Lisa

    2005-06-01

    Violent episodes of star formation occur in galaxies infalling into clusters when they first encounter the intra-cluster medium (ICM). Most of this star formation is dust-absorbed and therefore only observable through mid- and far-IR observations. In the long term, ram pressure and tidal interactions in the densest central region of the cluster strip gas and dust from these galaxies suppressing star-formation and enriching the ICM. A concentration of cold diffuse dust is thus expected in cluster cores and its emission can be only observed in the far-IR. We propose to map three rich clusters at redshift z=0.2 with MIPS and IRAC up to two virial radii. These clusters have been selected in regions of exceptionally low Galactic absorption to study faint mid-IR sources and put stringent limits on the far-IR diffuse emission from cold dust. The observations will be deep enough to detect star forming galaxies down to a star-formation rate of one solar mass per year, to compute the global star formation in clusters and compare the average star formation with that of coeval field galaxies. Rich clusters are commonly found at high redshift in wide-field Spitzer surveys. However, locally, they are extremely rare. These observation will provide a reference sample for studying evolutionary effects with the same class of objects.

  20. 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.

  1. Robust image segmentation using local robust statistics and correntropy-based K-means clustering

    NASA Astrophysics Data System (ADS)

    Huang, Chencheng; Zeng, Li

    2015-03-01

    It is an important work to segment the real world images with intensity inhomogeneity such as magnetic resonance (MR) and computer tomography (CT) images. In practice, such images are often polluted by noise which make them difficult to be segmented by traditional level set based segmentation models. In this paper, we propose a robust level set image segmentation model combining local with global fitting energies to segment noised images. In the proposed model, the local fitting energy is based on the local robust statistics (LRS) information of an input image, which can efficiently reduce the effects of the noise, and the global fitting energy utilizes the correntropy-based K-means (CK) method, which can adaptively emphasize the samples that are close to their corresponding cluster centers. By integrating the advantages of global information and local robust statistics characteristics, the proposed model can efficiently segment images with intensity inhomogeneity and noise. Then, a level set regularization term is used to avoid re-initialization procedures in the process of curve evolution. In addition, the Gaussian filter is utilized to keep the level set smoothing in the curve evolution process. The proposed model first appeared as a two-phase model and then extended to a multi-phase one. Experimental results show the advantages of our model in terms of accuracy and robustness to the noise. In particular, our method has been applied on some synthetic and real images with desirable results.

  2. 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

  3. Detecting cancer clusters in a regional population with local cluster tests and Bayesian smoothing methods: a simulation study

    PubMed Central

    2013-01-01

    Background There is a rising public and political demand for prospective cancer cluster monitoring. But there is little empirical evidence on the performance of established cluster detection tests under conditions of small and heterogeneous sample sizes and varying spatial scales, such as are the case for most existing population-based cancer registries. Therefore this simulation study aims to evaluate different cluster detection methods, implemented in the open soure environment R, in their ability to identify clusters of lung cancer using real-life data from an epidemiological cancer registry in Germany. Methods Risk surfaces were constructed with two different spatial cluster types, representing a relative risk of RR = 2.0 or of RR = 4.0, in relation to the overall background incidence of lung cancer, separately for men and women. Lung cancer cases were sampled from this risk surface as geocodes using an inhomogeneous Poisson process. The realisations of the cancer cases were analysed within small spatial (census tracts, N = 1983) and within aggregated large spatial scales (communities, N = 78). Subsequently, they were submitted to the cluster detection methods. The test accuracy for cluster location was determined in terms of detection rates (DR), false-positive (FP) rates and positive predictive values. The Bayesian smoothing models were evaluated using ROC curves. Results With moderate risk increase (RR = 2.0), local cluster tests showed better DR (for both spatial aggregation scales > 0.90) and lower FP rates (both < 0.05) than the Bayesian smoothing methods. When the cluster RR was raised four-fold, the local cluster tests showed better DR with lower FPs only for the small spatial scale. At a large spatial scale, the Bayesian smoothing methods, especially those implementing a spatial neighbourhood, showed a substantially lower FP rate than the cluster tests. However, the risk increases at this scale were mostly diluted by data

  4. Hybrid systems for virtual screening: interest of fuzzy clustering applied to olfaction.

    PubMed

    Ros, F; Audouze, K; Pintore, M; Chrétien, J R

    2000-01-01

    Kohonen neural networks, also known as Self Organizing Map (SOM), offer a useful 2D representation of the compound distribution inside a large chemical database. This distribution results from the compound organization in a molecular diversity hyperspace derived from a large set of molecular descriptors. Fuzzy techniques based on the "concept of partial truth" reveal to be also a valuable tool for the direct exploitation of chemical databases or SOM. In such cases a fuzzy clustering algorithm is used. In this paper, a complete hybrid system, combining SOM and fuzzy clustering, is applied. As example, a series of olfactory compounds was selected. The complexity of such information is that a same compound may exhibit different odors. It is shown how fuzzy logic helps to have a better understanding of the organization of the compounds. These hybrid systems, using simultaneously SOM and fuzzy clustering, are foreseen as powerful tools for "virtual pre-screening". PMID:10969876

  5. Multiple-aperture speckle method applied to local displacement measurements

    NASA Astrophysics Data System (ADS)

    Ángel, Luciano; Tebaldi, Myrian; Bolognini, Néstor

    2007-06-01

    The goal of this work is to analyze the measurement capability of the modified speckle photography technique that uses different multiple aperture pupils in a multiple exposure scheme. In particular, the rotation case is considered. A point-wise analysis procedure is utilized to obtain the fringes required to access to the local displacement measurements. The proposed arrangement allows simultaneous displaying in the Fourier plane several fringes system each one associated with different rotations. We experimentally verified that the local displacement measurements can be determined with a high precision and accuracy.

  6. 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.

  7. Applying Social Networking and Clustering Algorithms to Galaxy Groups in ALFALFA

    NASA Astrophysics Data System (ADS)

    Bramson, Ali; Wilcots, E. M.

    2012-01-01

    Because most galaxies live in groups, and the environment in which it resides affects the evolution of a galaxy, it is crucial to develop tools to understand how galaxies are distributed within groups. At the same time we must understand how groups are distributed and connected in the larger scale structure of the Universe. I have applied a variety of networking techniques to assess the substructure of galaxy groups, including distance matrices, agglomerative hierarchical clustering algorithms and dendrograms. We use distance matrices to locate groupings spatially in 3-D. Dendrograms created from agglomerative hierarchical clustering results allow us to quantify connections between galaxies and galaxy groups. The shape of the dendrogram reveals if the group is spatially homogenous or clumpy. These techniques are giving us new insight into the structure and dynamical state of galaxy groups and large scale structure. We specifically apply these techniques to the ALFALFA survey of the Coma-Abell 1367 supercluster and its resident galaxy groups.

  8. Transaural virtual reality applied to front-back localization

    NASA Astrophysics Data System (ADS)

    Zhang, Peter Xinya; Hartmann, William M.

    2005-04-01

    Human sound localization can be studied by measuring head-related transfer functions for different source locations and subsequently using the data to simulate different spatial locations using headphone presentation. This technique fails to adequately simulate the difference between front and back locations because the frequencies relevant to pinna cues are so high. A transaural (cross-talk cancellation) technique has been developed that is accurate up to 16 kHz. By controlling the levels and phases of spectral components, as measured by probe microphones in the ear canals, the technique eliminates significant differences between the baseline simulation and reality. The technique has been used, with modifications to the baseline simulation, to study the front-back information content in different frequency bands by eliminating the information while maintaining the energy. It has also been used to test for orthogonality between front-back localization and azimuthal localization based on simple interaural differences. The technique has verified that front-back discrimination cannot be mediated by interaural differences alone. By flattening the level spectrum in one ear while leaving the other ear unchanged it has been possible to demonstrate an ear advantage for front-back discrimination. [Work supported by the NIDCD, grant DC 00181.

  9. 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.

  10. 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.

  11. Predicting item popularity: Analysing local clustering behaviour of users

    NASA Astrophysics Data System (ADS)

    Liebig, Jessica; Rao, Asha

    2016-01-01

    Predicting the popularity of items in rating networks is an interesting but challenging problem. This is especially so when an item has first appeared and has received very few ratings. In this paper, we propose a novel approach to predicting the future popularity of new items in rating networks, defining a new bipartite clustering coefficient to predict the popularity of movies and stories in the MovieLens and Digg networks respectively. We show that the clustering behaviour of the first user who rates a new item gives insight into the future popularity of that item. Our method predicts, with a success rate of over 65% for the MovieLens network and over 50% for the Digg network, the future popularity of an item. This is a major improvement on current results.

  12. Performance of small cluster surveys and the clustered LQAS design to estimate local-level vaccination coverage in Mali

    PubMed Central

    2012-01-01

    Background Estimation of vaccination coverage at the local level is essential to identify communities that may require additional support. Cluster surveys can be used in resource-poor settings, when population figures are inaccurate. To be feasible, cluster samples need to be small, without losing robustness of results. The clustered LQAS (CLQAS) approach has been proposed as an alternative, as smaller sample sizes are required. Methods We explored (i) the efficiency of cluster surveys of decreasing sample size through bootstrapping analysis and (ii) the performance of CLQAS under three alternative sampling plans to classify local VC, using data from a survey carried out in Mali after mass vaccination against meningococcal meningitis group A. Results VC estimates provided by a 10 × 15 cluster survey design were reasonably robust. We used them to classify health areas in three categories and guide mop-up activities: i) health areas not requiring supplemental activities; ii) health areas requiring additional vaccination; iii) health areas requiring further evaluation. As sample size decreased (from 10 × 15 to 10 × 3), standard error of VC and ICC estimates were increasingly unstable. Results of CLQAS simulations were not accurate for most health areas, with an overall risk of misclassification greater than 0.25 in one health area out of three. It was greater than 0.50 in one health area out of two under two of the three sampling plans. Conclusions Small sample cluster surveys (10 × 15) are acceptably robust for classification of VC at local level. We do not recommend the CLQAS method as currently formulated for evaluating vaccination programmes. PMID:23057445

  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. A Technique of Two-Stage Clustering Applied to Environmental and Civil Engineering and Related Methods of Citation Analysis.

    ERIC Educational Resources Information Center

    Miyamoto, S.; Nakayama, K.

    1983-01-01

    A method of two-stage clustering of literature based on citation frequency is applied to 5,065 articles from 57 journals in environmental and civil engineering. Results of related methods of citation analysis (hierarchical graph, clustering of journals, multidimensional scaling) applied to same set of articles are compared. Ten references are…

  15. Dissecting trait heterogeneity: a comparison of three clustering methods applied to genotypic data

    PubMed Central

    Thornton-Wells, Tricia A; Moore, Jason H; Haines, Jonathan L

    2006-01-01

    Background Trait heterogeneity, which exists when a trait has been defined with insufficient specificity such that it is actually two or more distinct traits, has been implicated as a confounding factor in traditional statistical genetics of complex human disease. In the absence of detailed phenotypic data collected consistently in combination with genetic data, unsupervised computational methodologies offer the potential for discovering underlying trait heterogeneity. The performance of three such methods – Bayesian Classification, Hypergraph-Based Clustering, and Fuzzy k-Modes Clustering – appropriate for categorical data were compared. Also tested was the ability of these methods to detect trait heterogeneity in the presence of locus heterogeneity and/or gene-gene interaction, which are two other complicating factors in discovering genetic models of complex human disease. To determine the efficacy of applying the Bayesian Classification method to real data, the reliability of its internal clustering metrics at finding good clusterings was evaluated using permutation testing. Results Bayesian Classification outperformed the other two methods, with the exception that the Fuzzy k-Modes Clustering performed best on the most complex genetic model. Bayesian Classification achieved excellent recovery for 75% of the datasets simulated under the simplest genetic model, while it achieved moderate recovery for 56% of datasets with a sample size of 500 or more (across all simulated models) and for 86% of datasets with 10 or fewer nonfunctional loci (across all simulated models). Neither Hypergraph Clustering nor Fuzzy k-Modes Clustering achieved good or excellent cluster recovery for a majority of datasets even under a restricted set of conditions. When using the average log of class strength as the internal clustering metric, the false positive rate was controlled very well, at three percent or less for all three significance levels (0.01, 0.05, 0.10), and the false

  16. A Projector-Embedding Approach for Multiscale Coupled-Cluster Calculations Applied to Citrate Synthase.

    PubMed

    Bennie, Simon J; van der Kamp, Marc W; Pennifold, Robert C R; Stella, Martina; Manby, Frederick R; Mulholland, Adrian J

    2016-06-14

    Projector-based embedding has recently emerged as a robust multiscale method for the calculation of various electronic molecular properties. We present the coupling of projector embedding with quantum mechanics/molecular mechanics modeling and apply it for the first time to an enzyme-catalyzed reaction. Using projector-based embedding, we combine coupled-cluster theory, density-functional theory (DFT), and molecular mechanics to compute energies for the proton abstraction from acetyl-coenzyme A by citrate synthase. By embedding correlated ab initio methods in DFT we eliminate functional sensitivity and obtain high-accuracy profiles in a procedure that is straightforward to apply. PMID:27159381

  17. Charge localization on the hexa-interstitial cluster in MgO.

    PubMed

    Mulroue, J; Uberuaga, B P; Duffy, D M

    2013-02-13

    Density functional theory was used to study the effects of charge localization on the structure and mobility of the highly mobile hexa-interstitial cluster in MgO. It was found that the relative stability of the configurations changed as charge was localized, with the higher energy intermediate configuration of the neutral cluster becoming the lowest energy configuration for the doubly charged cluster. The singly charged cluster was found to have the lowest migration barrier, with a barrier of 0.18 eV. The high mobility of the singly charged hexa-interstitial cluster could have a significant effect on microstructure evolution following radiation damage, while the detailed properties will be sensitive to the level of doping in the material. PMID:23307696

  18. 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

  19. 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.

  20. Alignments of the Galaxies in and around the Virgo Cluster with the Local Velocity Shear

    NASA Astrophysics Data System (ADS)

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

    2014-08-01

    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.

  1. Commute time distance transformation applied to spectral imagery and its utilization in material clustering

    NASA Astrophysics Data System (ADS)

    Albano, James A.; Messinger, David W.; Rotman, Stanley R.

    2012-07-01

    Spectral image analysis problems often begin by applying a transformation that generates an alternative representation of the spectral data with the intention of exposing hidden features not discernable in the original space. We introduce and demonstrate a transformation based on a Markov-chain model of a random walk on a graph via application to spectral image clustering. The random walk is quantified by a measure known as the average commute time distance (CTD), which is the average length that a random walker takes, when starting at one node, to transition to another and return to the starting node. This distance metric has the important characteristic of increasing when the number of paths between two nodes decreases and/or the lengths of those paths increase. Once a similarity graph is built on the spectral data, a transformation based on an eigendecomposition of the graph Laplacian matrix is applied that embeds the nodes of the graph into a Euclidean space with the separation between nodes equal to the square-root of the average commute time distance. This is referred to as the Commute Time Distance transformation. As an example of the utility of this data transformation, results are shown for standard clustering algorithms applied to hyperspectral data sets.

  2. 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.

  3. 20 CFR 666.300 - What performance indicators apply to local areas?

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 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 local... satisfaction indicators that apply to the State under § 666.100(a). (b) In addition to the indicators...

  4. 28 CFR 65.85 - Procedures for State or local governments applying for funding.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 28 Judicial Administration 2 2010-07-01 2010-07-01 false Procedures for State or local governments applying for funding. 65.85 Section 65.85 Judicial Administration DEPARTMENT OF JUSTICE (CONTINUED) EMERGENCY FEDERAL LAW ENFORCEMENT ASSISTANCE Immigration Emergency Fund § 65.85 Procedures for State or local governments applying for funding....

  5. 20 CFR 666.300 - What performance indicators apply to local areas?

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 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 local... satisfaction indicators that apply to the State under § 666.100(a). (b) In addition to the indicators...

  6. 20 CFR 666.300 - What performance indicators apply to local areas?

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 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 local... satisfaction indicators that apply to the State under § 666.100(a). (b) In addition to the indicators...

  7. 20 CFR 666.300 - What performance indicators apply to local areas?

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 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 investment... indicators that apply to the State under § 666.100(a). (b) In addition to the indicators described...

  8. Estimated number of field stars toward Galactic globular clusters and Local Group Galaxies

    NASA Technical Reports Server (NTRS)

    Ratnatunga, K. U.; Bahcall, J. N.

    1985-01-01

    Field star densities are estimated for 89 fields with /b/ greater than 10 degrees based on the Galaxy model of Bahcall and Soneira (1980, 1984; Bahcall et al. 1985). Calculated tables are presented for 76 of the fields toward Galactic globular clusters, and 16 Local Group Galaxies in 13 fields. The estimates can be used as an initial guide for planning both ground-based and Space Telescope observations of globular clusters at intermediate-to-high Galactic latitudes.

  9. 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

  10. 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

  11. 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

  12. The effect of local approximations in the ground-state coupled cluster wave function on electron affinities of large molecules

    NASA Astrophysics Data System (ADS)

    Korona, Tatiana

    2012-02-01

    A possibility to calculate electron affinities (EAs) by a software devised for electron excitations is exploited to examine the accuracy of a partly local EA-EOM-CCSD method. In the proposed approach local approximations are applied to the ground-state coupled cluster wave function, while the EAs themselves are obtained in a full configurational space. The results of a numerical test for 14 molecules show that already with standard local settings the method reproduces the nonlocal EAs with the average error of 0.009 eV. Since the EA-EOM step of the calculation requires less computational resources than the computation of the CCSD ground state, the proposed hybrid approach can become a valuable tool for obtaining the EAs for molecules, which are too large for a canonical CCSD calculation, but still small enough for the EA-EOM step to be performed in a nonlocal way.

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

    NASA Astrophysics Data System (ADS)

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

    2016-04-01

    We present Gemini/GMOS imaging of twelve candidate intergalactic globular clusters (IGCs) in the Local Group, identified in a recent survey of the SDSS footprint by di Tullio Zinn & Zinn (2015). Our image quality is sufficiently high, at ˜0.4″ - 0.7″, that we are able to unambiguously classify all twelve 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 (2015) 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% chance of non-detection.

  14. Proximity effect assisted absorption enhancement in thin film with locally clustered nanoholes.

    PubMed

    Wu, Shaolong; Zhang, Cheng; Li, Xiaofeng; Zhan, Yaohui

    2015-03-01

    We focus on the light-trapping characteristics of a thin film with locally clustered nanoholes (NHs), considering that the clustering effect is usually encountered in preparing the nanostructures. Our full-wave finite-element simulation indicates that an intentionally introduced clustering effect could be employed for improving the light-trapping performance of the nanostructured thin film. For a 100 nm thick amorphous silicon film, an optimal clustering design with NH diameter of 100 nm is able to double the integrated optical absorption over the solar spectrum, compared to the planar counterpart, as well as show much improved optical performance over that of the nonclustered setup. A further insight into the underlying physics explains the outstanding light-trapping capability in terms of the increased available modes, a stronger power coupling efficiency, a higher fraction of electric field concentrated in absorbable material, and a higher density of photon states. PMID:25723434

  15. Dynamic screening of a localized hole during photoemission from a metal cluster

    PubMed Central

    2012-01-01

    Recent advances in attosecond spectroscopy techniques have fueled the interest in the theoretical description of electronic processes taking place in the subfemtosecond time scale. Here we study the coupled dynamic screening of a localized hole and a photoelectron emitted from a metal cluster using a semi-classical model. Electron density dynamics in the cluster is calculated with time-dependent density functional theory, and the motion of the photoemitted electron is described classically. We show that the dynamic screening of the hole by the cluster electrons affects the motion of the photoemitted electron. At the very beginning of its trajectory, the photoemitted electron interacts with the cluster electrons that pile up to screen the hole. Within our model, this gives rise to a significant reduction of the energy lost by the photoelectron. Thus, this is a velocity-dependent effect that should be accounted for when calculating the average losses suffered by photoemitted electrons in metals. PMID:22873820

  16. 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.

  17. 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 LABOR PERFORMANCE ACCOUNTABILITY UNDER TITLE I OF THE WORKFORCE INVESTMENT ACT Local Measures of Performance § 666.300 What performance...

  18. 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.

  19. 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…

  20. 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. PMID:25045741

  1. 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

  2. Geographic Informations Systems and Pharmacoepidemiology: Using spatial cluster detection to monitor local patterns of prescription opioid abuse

    PubMed Central

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

    2010-01-01

    Purpose Understanding the spatial distribution of opioid abuse at the local level may facilitate public health interventions. Methods Using patient-level data from addiction treatment facilities in New Mexico from ASI-MV® Connect, we applied geographic information system in combination with a spatial scan statistics 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. Results Data on 24,452 patients residing in New Mexico was 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). Conclusions A better understanding of local risk distribution may have implications for response strategies to future introductions of prescription opioids. PMID:20535759

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

    NASA Astrophysics Data System (ADS)

    Sánchez-Conde, Miguel A.; Cannoni, Mirco; Zandanel, Fabio; Gómez, Mario E.; Prada, Francisco

    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

  4. 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

  5. Psychological Factors Predict Local and Referred Experimental Muscle Pain: A Cluster Analysis in Healthy Adults

    PubMed Central

    Lee, Jennifer E.; Watson, David; Frey-Law, Laura A.

    2012-01-01

    Background Recent studies suggest an underlying three- or four-factor structure explains the conceptual overlap and distinctiveness of several negative emotionality and pain-related constructs. However, the validity of these latent factors for predicting pain has not been examined. Methods A cohort of 189 (99F; 90M) healthy volunteers completed eight self-report negative emotionality and pain-related measures (Eysenck Personality Questionnaire-Revised; Positive and Negative Affect Schedule; State-Trait Anxiety Inventory; Pain Catastrophizing Scale; Fear of Pain Questionnaire; Somatosensory Amplification Scale; Anxiety Sensitivity Index; Whiteley Index). Using principal axis factoring, three primary latent factors were extracted: General Distress; Catastrophic Thinking; and Pain-Related Fear. Using these factors, individuals clustered into three subgroups of high, moderate, and low negative emotionality responses. Experimental pain was induced via intramuscular acidic infusion into the anterior tibialis muscle, producing local (infusion site) and/or referred (anterior ankle) pain and hyperalgesia. Results Pain outcomes differed between clusters (multivariate analysis of variance and multinomial regression), with individuals in the highest negative emotionality cluster reporting the greatest local pain (p = 0.05), mechanical hyperalgesia (pressure pain thresholds; p = 0.009) and greater odds (2.21 OR) of experiencing referred pain compared to the lowest negative emotionality cluster. Conclusion Our results provide support for three latent psychological factors explaining the majority of the variance between several pain-related psychological measures, and that individuals in the high negative emotionality subgroup are at increased risk for (1) acute local muscle pain; (2) local hyperalgesia; and (3) referred pain using a standardized nociceptive input. PMID:23165778

  6. Hierarchical cluster analysis applied to workers' exposures in fiberglass insulation manufacturing.

    PubMed

    Wu, J D; Milton, D K; Hammond, S K; Spear, R C

    1999-01-01

    The objectives of this study were to explore the application of cluster analysis to the characterization of multiple exposures in industrial hygiene practice and to compare exposure groupings based on the result from cluster analysis with that based on non-measurement-based approaches commonly used in epidemiology. Cluster analysis was performed for 37 workers simultaneously exposed to three agents (endotoxin, phenolic compounds and formaldehyde) in fiberglass insulation manufacturing. Different clustering algorithms, including complete-linkage (or farthest-neighbor), single-linkage (or nearest-neighbor), group-average and model-based clustering approaches, were used to construct the tree structures from which clusters can be formed. Differences were observed between the exposure clusters constructed by these different clustering algorithms. When contrasting the exposure classification based on tree structures with that based on non-measurement-based information, the results indicate that the exposure clusters identified from the tree structures had little in common with the classification results from either the traditional exposure zone or the work group classification approach. In terms of the defining homogeneous exposure groups or from the standpoint of health risk, some toxicological normalization in the components of the exposure vector appears to be required in order to form meaningful exposure groupings from cluster analysis. Finally, it remains important to see if the lack of correspondence between exposure groups based on epidemiological classification and measurement data is a peculiarity of the data or a more general problem in multivariate exposure analysis. PMID:10028893

  7. 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. PMID:25197713

  8. 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

  9. 20 CFR 666.420 - Under what circumstances may a sanction be applied to local areas for poor performance?

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    .... The Governor's final decision may be appealed by the Local Board to the Secretary under 20 CFR 667.650... applied to local areas for poor performance? 666.420 Section 666.420 Employees' Benefits EMPLOYMENT AND... sanction be applied to local areas for poor performance? (a) If a local area fails to meet the levels...

  10. 20 CFR 666.420 - Under what circumstances may a sanction be applied to local areas for poor performance?

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    .... The Governor's final decision may be appealed by the Local Board to the Secretary under 20 CFR 667.650... applied to local areas for poor performance? 666.420 Section 666.420 Employees' Benefits EMPLOYMENT AND... may a sanction be applied to local areas for poor performance? (a) If a local area fails to meet...

  11. 20 CFR 666.420 - Under what circumstances may a sanction be applied to local areas for poor performance?

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    .... The Governor's final decision may be appealed by the Local Board to the Secretary under 20 CFR 667.650... applied to local areas for poor performance? 666.420 Section 666.420 Employees' Benefits EMPLOYMENT AND... may a sanction be applied to local areas for poor performance? (a) If a local area fails to meet...

  12. 20 CFR 666.420 - Under what circumstances may a sanction be applied to local areas for poor performance?

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    .... The Governor's final decision may be appealed by the Local Board to the Secretary under 20 CFR 667.650... applied to local areas for poor performance? 666.420 Section 666.420 Employees' Benefits EMPLOYMENT AND... sanction be applied to local areas for poor performance? (a) If a local area fails to meet the levels...

  13. Binary systems, star clusters and the Galactic-field population. Applied stellar dynamics

    NASA Astrophysics Data System (ADS)

    Kroupa, Pavel

    2002-01-01

    This book contains the results of recent theoretical work on the evolution of primordial binary systems in young star clusters, their effect on the evolution of their host clusters, implications for the distribution of young stars in the Milky Way, and the formation of bound star clusters. This work shows that if the Galactic-field binary population is a dynamically evolved version of the Taurus-Auriga pre-main sequence population, then most stars form in clusters with typically a few hundred binaries within a radius of about 0.5-1 pc. The results also suggest that the population I primordial binary-star orbital-parameter distribution functions may be universal, much like the initial mass function. Most solar-like planetary systems can survive in such clusters. The work presented here also establishes that most observed triple and quadruple systems must be primordial, but that α Cen A/B-Proxima Cen-like systems can form in clusters through dynamical capture. Precise N-body calculations using Aarseth's N-body codes of clusters containing up to 104 stars are used to create an extensive young-cluster library. These data demonstrate that the primordial binary systems are disrupted on a crossing-time scale, and that the truncation of the surviving period distribution measures the maximum concentration the cluster ever experienced. The N-body calculations demonstrate that Galactic star clusters form readily as nuclei of expanding OB associations despite a star-formation efficiency of typically 30 per cent and gas-expulsion over a time-span shorter than the cluster crossing time.

  14. 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

  15. 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…

  16. 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…

  17. 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.

  18. 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.

  19. 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.

  20. Local Correlation Calculations Using Standard and Renormalized Coupled-Cluster Methods

    NASA Astrophysics Data System (ADS)

    Piecuch, Piotr; Li, Wei; Gour, Jeffrey

    2009-03-01

    Local correlation variants of the coupled-cluster (CC) theory with singles and doubles (CCSD) and CC methods with singles, doubles, and non-iterative triples, including CCSD(T) and the completely renormalized CR-CC(2,3) approach, are developed. The main idea of the resulting CIM-CCSD, CIM-CCSD(T), and CIM-CR-CC(2,3) methods is the realization of the fact that the total correlation energy of a large system can be obtained as a sum of contributions from the occupied orthonormal localized molecular orbitals and their respective occupied and unoccupied orbital domains. The CIM-CCSD, CIM-CCSD(T), and CIM-CR-CC(2,3) algorithms are characterized by the linear scaling of the total CPU time with the system size and embarrassing parallelism. By comparing the results of the canonical and CIM-CC calculations for normal alkanes and water clusters, it is demonstrated that the CIM-CCSD, CIM-CCSD(T), and CIM-CR-CC(2,3) approaches recover the corresponding canonical CC correlation energies to within 0.1 % or so, while offering savings in the computer effort by orders of magnitude. By examining the dissociation of dodecane into C11H23 and CH3 and several lowest-energy structures of the (H2O)n clusters, it is shown that the CIM-CC methods accurately reproduce the relative energetics of the corresponding canonical CC calculations.

  1. GraphClust: alignment-free structural clustering of local RNA secondary structures

    PubMed Central

    Rose, Dominic; Backofen, Rolf

    2012-01-01

    Motivation: Clustering according to sequence–structure similarity has now become a generally accepted scheme for ncRNA annotation. Its application to complete genomic sequences as well as whole transcriptomes is therefore desirable but hindered by extremely high computational costs. Results: We present a novel linear-time, alignment-free method for comparing and clustering RNAs according to sequence and structure. The approach scales to datasets of hundreds of thousands of sequences. The quality of the retrieved clusters has been benchmarked against known ncRNA datasets and is comparable to state-of-the-art sequence–structure methods although achieving speedups of several orders of magnitude. A selection of applications aiming at the detection of novel structural ncRNAs are presented. Exemplarily, we predicted local structural elements specific to lincRNAs likely functionally associating involved transcripts to vital processes of the human nervous system. In total, we predicted 349 local structural RNA elements. Availability: The GraphClust pipeline is available on request. Contact: backofen@informatik.uni-freiburg.de Supplementary information: Supplementary data are available at Bioinformatics online. PMID:22689765

  2. 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…

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

    NASA Astrophysics Data System (ADS)

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

    2013-09-01

    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.

  4. 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}.

  5. 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. PMID:27257884

  6. [Clustering analysis applied to near-infrared spectroscopy analysis of Chinese traditional medicine].

    PubMed

    Liu, Mu-qing; Zhou, De-cheng; Xu, Xin-yuan; Sun, Yao-jie; Zhou, Xiao-li; Han, Lei

    2007-10-01

    The present article discusses the clustering analysis used in the near-infrared (NIR) spectroscopy analysis of Chinese traditional medicines, which provides a new method for the classification of Chinese traditional medicines. Samples selected purposely in the authors' research to measure their absorption spectra in seconds by a multi-channel NIR spectrometer developed in the authors' lab were safrole, eucalypt oil, laurel oil, turpentine, clove oil and three samples of costmary oil from different suppliers. The spectra in the range of 0.70-1.7 microm were measured with air as background and the results indicated that they are quite distinct. Qualitative mathematical model was set up and cluster analysis based on the spectra was carried out through different clustering methods for optimization, and came out the cluster correlation coefficient of 0.9742 in the authors' research. This indicated that cluster analysis of the group of samples is practicable. Also it is reasonable to get the result that the calculated classification of 8 samples was quite accorded with their characteristics, especially the three samples of costmary oil were in the closest classification of the clustering analysis. PMID:18306778

  7. 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.

  8. Localization of glucose-dependent insulinotropic polypeptide (GIP) to a gene cluster on chromosome 17q

    SciTech Connect

    Lewis, T.B.; Saenz, M.; O'Connell, P.; Leach, R.J. )

    1994-02-01

    Glucose-dependent insulinotropic polypeptide (GIP) has been regionally localized to a gene cluster on human chromosome 17q. Genetic mapping through CEPH reference families demonstrated that GIP was tightly linked to NME1 and PPY and fully linked to HOXB6 and NGFR. High-resolution radiation hybrid mapping resolved the gene order as cen-PPY-HOXB6-NGFR-GIP-NME1-tel. GIP maps distal to NGFR with an estimated distance of 250 kb. 12 refs., 1 fig., 1 fig.

  9. Simultaneous detection and localization of secondary ions and electrons from single large cluster impacts

    PubMed Central

    Eller, M. J.; Verkhoturov, S. V.; Fernandez-Lima, F. A.; DeBord, J. D.; Schweikert, E. A.; Della-Negra, S.

    2013-01-01

    The use of large cluster primary ions (e.g. C60, Au400) in secondary ion mass spectrometry has become prevalent in recent years due to their enhanced emission of secondary ions, in particular, molecular ions (MW ≤ 1500 Da). The co-emission of electrons with SIs was investigated per projectile impact. It has been found that SI and electrons yields increased with increasing projectile energy and size. The use of the emitted electrons from impacts of C60 for localization has been demonstrated for cholesterol deposited on a copper grid. The instrumentation, methodologies, and results from these experiments are presented. PMID:24163488

  10. 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.

  11. Locally Applied Valproate Enhances Survival in Rats after Neocortical Treatment with Tetanus Toxin and Cobalt Chloride

    PubMed Central

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

    2013-01-01

    Purpose. 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). Methods. 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. Results. 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. Conclusions. 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. PMID:24151604

  12. HALR: A TCP Enhancement Scheme Using Local Caching in High-Availability Cluster

    NASA Astrophysics Data System (ADS)

    Feng, Yi-Hsuan; Huang, Nen-Fu; Wu, Yen-Min

    In this paper, we study the end-to-end TCP performance over a path deploying a High-Availability cluster, whose characteristics are highlighted by the failover procedure to remove single-point failure. This paper proposes an approach, called High-Availability Local Recovery (HALR), to enhance TCP performance in the face of a cluster failover. To minimize the latency of retransmission, HALR saves TCP packets selectively and resends them locally after the failover is finished. For better understanding, we further develop simple analytic models to predict the TCP performance in the aspect of flow latency under a range of failover times and the effects of HALR. Using simulation results, we validate our models and show that HALR improves the TCP performance significantly over a failover event as compared with the original TCP. Typically, HALR reduces the flow latency from 4.1sec to less than 1.9sec when the failover time equals to 500ms. The simulation by real packet trace further demonstrates that the memory requirement of the proposed solution is not a concern for modern network equipments.

  13. A hierarchy of local coupled cluster singles and doubles response methods for ionization potentials

    NASA Astrophysics Data System (ADS)

    Wälz, Gero; Usvyat, Denis; Korona, Tatiana; Schütz, Martin

    2016-02-01

    We present a hierarchy of local coupled cluster (CC) linear response (LR) methods to calculate ionization potentials (IPs), i.e., excited states with one electron annihilated relative to a ground state reference. The time-dependent perturbation operator V(t), as well as the operators related to the first-order (with respect to V(t)) amplitudes and multipliers, thus are not number conserving and have half-integer particle rank m. Apart from calculating IPs of neutral molecules, the method offers also the possibility to study ground and excited states of neutral radicals as ionized states of closed-shell anions. It turns out that for comparable accuracy IPs require a higher-order treatment than excitation energies; an IP-CC LR method corresponding to CC2 LR or the algebraic diagrammatic construction scheme through second order performs rather poorly. We therefore systematically extended the order with respect to the fluctuation potential of the IP-CC2 LR Jacobian up to IP-CCSD LR, keeping the excitation space of the first-order (with respect to V(t)) cluster operator restricted to the m = /1 2 ⊕ /3 2 subspace and the accuracy of the zero-order (ground-state) amplitudes at the level of CC2 or MP2. For the more expensive diagrams beyond the IP-CC2 LR Jacobian, we employ local approximations. The implemented methods are capable of treating large molecular systems with hundred atoms or more.

  14. Local cluster-size statistics in the critical phase of bond percolation on the Cayley tree

    NASA Astrophysics Data System (ADS)

    Nogawa, Tomoaki; Hasegawa, Takehisa; Nemoto, Koji

    2016-05-01

    We study bond percolation of the Cayley tree (CT) by focusing on the probability distribution function (PDF) of a local variable, namely, the size of the cluster including a selected vertex. Because the CT does not have a dominant bulk region, which is free from the boundary effect, even in the large-size limit, the phase of the system on it is not well defined. We herein show that local observation is useful to define the phase of such a system in association with the well-defined phase of the system on the Bethe lattice, that is, an infinite regular tree without boundary. Above the percolation threshold, the PDFs of the vertex at the center of the CT (the origin) and of the vertices near the boundary of the CT (the leaves) have different forms, which are also dissimilar to the PDF observed in the ordinary percolating phase of a Euclidean lattice. The PDF for the origin of the CT is bimodal: a decaying exponential function and a system-size-dependent asymmetric peak, which obeys a finite-size-scaling law with a fractal exponent. These modes are respectively related to the PDFs of the finite and infinite clusters in the nonuniqueness phase of the Bethe lattice. On the other hand, the PDF for the leaf of the CT is a decaying power function. This is similar to the PDF observed at a critical point of a Euclidean lattice but is attributed to the nesting structure of the CT around the boundary.

  15. 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…

  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. 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

  18. 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

  19. 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

  20. Local Correlation Calculations Using Standard and Renormalized Coupled-Cluster Methods

    NASA Astrophysics Data System (ADS)

    Li, Wei; Piecuch, Piotr; Gour, Jeffrey R.

    2009-03-01

    This article discusses our recent effort toward the extension of the linear scaling local correlation approach, termed 'cluster-in-molecule' and abbreviated as CIM [S. Li, J. Ma, and Y. Jiang, J. Comput. Chem. 23, 237 (2002); S. Li, J. Shen, W. Li, and Y. Jiang, J. Chem. Phys. 125, 074109 (2006)], to the coupled-cluster (CC) theory with singles and doubles (CCSD) and CC methods with singles, doubles, and non-iterative triples, including the standard CCSD(T) approach and the completely renormalized CR-CC(2,3) scheme [P. Piecuch and M. Włoch, J. Chem. Phys. 123, 224105 (2005); P. Piecuch, M. Włoch, J. R. Gour, and A. Kinal, Chem. Phys. Lett. 418, 467 (2006)]. As in the earlier CIM work that dealt with the second-order many-body perturbation theory and CC doubles approach, the main idea of the CIM-CCSD, CIM-CCSD(T), and CIM-CR-CC(2,3) methods is the realization of the fact that the total correlation energy of a large system can be obtained as a sum of contributions from the occupied orthonormal localized molecular orbitals and their respective occupied and unoccupied orbital domains. The CIM-CCSD, CIM-CCSD(T), and CIM-CR-CC(2,3) methods pursued in this work are characterized by high computational efficiency in both the CIM and CC parts, enabling calculations for much larger systems than previously possible. This is achieved by combining the natural linear scaling and embarrassing parallelism of the CIM ansatz with the vectorized CC codes that rely on recursively generated intermediates and fast matrix multiplication routines. By comparing the results of the canonical and CIM-CC calculations for normal alkanes and water clusters, it is demonstrated that the CIM-CCSD, CIM-CCSD(T), and CIM-CR-CC(2,3) approaches recover the corresponding canonical CC correlation energies to within 0.1% or so, while offering linear scaling of the computer costs with the system size and savings in the computer effort by orders of magnitude. By examining the dissociation of dodecane into C

  1. 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

  2. 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

  3. 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

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

    PubMed

    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

  5. 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

  6. Noniterative Inclusion of the Triply and Quadruply Excited Clusters: The Locally Renormalized Perspective

    SciTech Connect

    Kowalski, Karol; De Jong, Wibe A.

    2006-08-31

    Noniterative inclusion of the higher=order clusters has been a subject of intensive studies aimed at developing a well balanced description of individual many-body contributions for entire ground-state potential energy surfaces. In traditional approaches, the connected quadruples are estimated directly based on perturbative arguments, which leads to excellent agreement with full CI results near the equilibrium geometry and increasingly worse energies for larger internuclear stretches. As a possible improvement to this situation, two techniques are considered as especially promising: perturbative approaches based on the similarity transformed Hamiltonians and renormalization schemes both in global and local formulation. Following the latter strategy we adopted the recently introduced Numerator-Denominator Connected expansion (NDC) [ K. Kowalski, P. Piecuch, J. Chem. Phys. 122 (2005) [074107] as an effective tool for designing new forms of noniterative corrections accounting for the joint effect of triples and quadruples. The performance of the ensuing locally renormalized CCSD(TQ) approaches (LR-CCSD(TQ) is illustrated on several examples that require either going beyond the triples approximation or describing very subtle effects encountered in Van der Waals complexes. Comparisons with other noniterative approaches are also made and some issues regarding the size-extensivity of the locally renormalized methods are addressed.

  7. Global spatiotemporal order and induced stochastic resonance due to a locally applied signal

    NASA Astrophysics Data System (ADS)

    Samoletov, A.; Chaplain, M.; Levi, V.

    2004-04-01

    We study the phenomenon of spatiotemporal stochastic resonance (STSR) in a chain of diffusively coupled bistable oscillators. In particular, we examine the situation in which the global STSR response is controlled by a locally applied signal and reveal a wave-front propagation. In order to deepen the understanding of the system dynamics, we introduce, on the time scale of STSR, the study of the effective statistical renormalization of a generic lattice system. Using this technique we provide a criterion for STSR, and predict and observe numerically a bifurcationlike behavior that reflects the difference between the most probable value of the local quasiequilibrium density and its mean value. Our results, tested with a chain of nonlinear oscillators, appear to possess some universal qualities and may stimulate a deeper search for more generic phenomena.

  8. 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. PMID:25314498

  9. Clustering of Local Group Distances: Publication Bias or Correlated Measurements? III. The Small Magellanic Cloud

    NASA Astrophysics Data System (ADS)

    de Grijs, Richard; Bono, Giuseppe

    2015-06-01

    Aiming at providing a firm mean distance estimate to the SMC, and thus to place it within the internally consistent Local Group distance framework we recently established, we compiled the current largest database of published distance estimates to the galaxy. Based on careful statistical analysis, we derive mean distance estimates to the SMC using eclipsing binary systems, variable stars, stellar population tracers, and star cluster properties. Their weighted mean leads to a final recommendation for the mean SMC distance of (m-M)0SMC=18.96+/- 0.02 mag, where the uncertainty represents the formal error. Systematic effects related to lingering uncertainties in extinction corrections, our physical understanding of the stellar tracers used, and the SMC's complex geometry—including its significant line of sight depth, its irregular appearance which renders definition of the galaxy's center uncertain, as well as its high inclination and possibly warped disk—may contribute additional uncertainties possibly exceeding 0.15-0.20 mag.

  10. Cluster Ion Beam Induced Nano Metallic Rippled Structures for Localized Surface Plasmon Resonance (LSPR) Based Sensors

    NASA Astrophysics Data System (ADS)

    Saleem, Iram; Tilakaratne, Buddhi; He, Yanzhi; Nzumbe, Epie; Wijesundera, Dharshana; Chen, Quark; Chu, Wei-Kan

    2015-03-01

    Localized surface plasmon resonance (LSPR) based bio sensors have a high sensitivity and exploit a label free real time analytical detection mechanism. We have produced plasmonic nano-structured substrates by cluster ion beam irradiation of thin gold films and have studied their effectiveness as potential plasmonic sensors. By adsorbing a mono-layer of thiolated organic compounds on the surface of these substrates we identified the shift in the LSPR peaks triggered by the change of dielectric function in the neighborhood of the structures. These plasmonic nano-metallic structures can be utilized to observe the change of LSPR resonance frequency due to adsorption, re-adsorption and reactions taking place on the surface that can potentially be mapped to reaction mechanics

  11. Applying and assessing some semi-local density functionals for condensed matter physics and quantum chemistry

    NASA Astrophysics Data System (ADS)

    Hao, Pan

    Density functional theory (DFT) is a widely used quantum mechanical method for the simulation of the electronic structure of atoms, molecules, and solids. The only part that needs to be approximated is the exchange-correlation energy as a functional of the electron density. After many-year development, there is a huge variety of exchange-correlation functionals. According to the ingredients, an exchange-correlation functional can be classified as a semi-local functional or beyond. A semi-local functional can be nonempirical or empirical and only uses locality information, such as electron density, gradient of the density, Laplacian of the density, and kinetic energy density. Unlike a non-local functional that uses non-locality information, a semi-local functional is computationally efficient and can be applied to large systems. The meta-generalized gradient approximation (meta-GGA), which is the highest-level semi-local functional, has the potential to give a good description for condensed matter physics and quantum chemistry. We built the self-consistent revised Tao-Perdew-Staroverov-Scuseria (revTPSS) meta-GGA into the band-structure program BAND to test the performances of some self-consistent semi-local functionals on lattice constant with a 58-solid test set. The self-consistent effect of revTPSS was also discussed. The vibration of a crystal has a contribution to the ground state energy of a system, which is the zero-point energy at zero temperature. It has anharmonicity at the equilibrium geometry. The standard DFT doesn't consider the zero-point energy of a crystal. We used density functional perturbation theory (DFPT), which is a powerful and flexible theoretical technique within the density functional framework, to study the zero-point energy and make a correction to the lattice constant. The method was compared to a traditional zero-point anharmonic expansion method that is based on the Debye and Dugdale-MacDonald approximations. We also tested some new

  12. 20 CFR 669.555 - Do the WIA administrative cost limits for States and local areas apply to NFJP grants?

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... the WIA administrative cost limits for States and local areas apply to NFJP grants? No, under 20 CFR... 20 Employees' Benefits 4 2012-04-01 2012-04-01 false Do the WIA administrative cost limits for States and local areas apply to NFJP grants? 669.555 Section 669.555 Employees' Benefits EMPLOYMENT...

  13. 20 CFR 669.555 - Do the WIA administrative cost limits for States and local areas apply to NFJP grants?

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... the WIA administrative cost limits for States and local areas apply to NFJP grants? No, under 20 CFR... 20 Employees' Benefits 4 2014-04-01 2014-04-01 false Do the WIA administrative cost limits for States and local areas apply to NFJP grants? 669.555 Section 669.555 Employees' Benefits EMPLOYMENT...

  14. 20 CFR 669.555 - Do the WIA administrative cost limits for States and local areas apply to NFJP grants?

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... the WIA administrative cost limits for States and local areas apply to NFJP grants? No, under 20 CFR... 20 Employees' Benefits 4 2013-04-01 2013-04-01 false Do the WIA administrative cost limits for States and local areas apply to NFJP grants? 669.555 Section 669.555 Employees' Benefits EMPLOYMENT...

  15. 20 CFR 669.555 - Do the WIA administrative cost limits for States and local areas apply to NFJP grants?

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... administrative cost limits for States and local areas apply to NFJP grants? No, under 20 CFR 667.210(b), limits... 20 Employees' Benefits 3 2010-04-01 2010-04-01 false Do the WIA administrative cost limits for States and local areas apply to NFJP grants? 669.555 Section 669.555 Employees' Benefits EMPLOYMENT...

  16. THREE CANDIDATE CLUSTERS OF GALAXIES AT REDSHIFT {approx}1.8: THE 'MISSING LINK' BETWEEN PROTOCLUSTERS AND LOCAL CLUSTERS?

    SciTech Connect

    Chiaberge, Marco; Macchetto, F. Duccio; Capetti, A.; Rosati, P.; Tozzi, P.; Tremblay, G. R.

    2010-02-20

    We present three candidate clusters of galaxies at redshifts most likely between 1.7 and 2.0, which corresponds to a fundamentally unexplored epoch of cluster evolution. The candidates were found by studying the environment around our newly selected sample of 'beacons' low-luminosity (FR I) radio galaxies in the COSMOS field. In this way, we intend to use the fact that FR Is at low z are almost invariably located in clusters of galaxies. We use the most accurate photometric redshifts available to date, derived by the COSMOS collaboration using photometry with a set of 30 filters, to look for three-dimensional space overdensities around our objects. Three out of the five FR Is in our sample which possess reliable photometric redshifts between z {sub phot} = 1.7 and 2.0 display overdensities that together are statistically significant at the 4{sigma} level, compared to field counts, arguing for the presence of rich clusters of galaxies in their Mpc environment. These first results show that the new method for finding high-z clusters we recently proposed, which makes use of low-power FR I radio galaxies instead of the more powerful FR II sources often used in the literature to date, is returning very promising candidates.

  17. 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.

  18. 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

  19. Hubble Space Telescope Snapshot Search for Planetary Nebulae in Globular Clusters of the Local Group

    NASA Astrophysics Data System (ADS)

    Bond, Howard E.

    2015-04-01

    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. Based on observations with the NASA/ESA Hubble Space Telescope obtained at the Space Telescope Science Institute, and from the data archive at STScI, which are operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS5-26555.

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

    PubMed

    Jacquez, Geoffrey M; Greiling, Dunrie A

    2003-02-17

    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

  1. IR double-resonance spectroscopy applied to the 4-aminophenol(H2O)1 cluster

    NASA Astrophysics Data System (ADS)

    Gerhards, M.; Unterberg, C.

    2001-04-01

    The IR double-resonance techniques IR/R2PI (infrared/resonant 2-photon ionization), IR/PIRI (infrared-photo-induced Rydberg ionization) and IR-photodissociation spectroscopy are valuable tools to investigate structure, vibrations, and dynamical processes of neutral and ionic hydrogen-bonded clusters containing aromatic molecules. In this paper we report on the application of the IR double-resonance techniques to determine the NH and OH stretching vibrations of 4-aminophenol and 4-aminophenol(H2O)1, both in the neutral (S0) and ionic (D0) ground state. All vibrational frequencies obtained for 4-aminophenol and the cluster are compared with the values obtained from ab initio and DFT calculations. In the S0 state, a trans-linear arrangement of 4-aminophenol(H2O)1 is obtained containing an O-H..O hydrogen bond. In the D0 state an overlay of two spectra can be observed resulting from the trans-linear structure and a second structure which contains a N-H..O hydrogen bond. The observation of these two structures within the ion is an interesting example of a rearrangement reaction in the ionic state.

  2. Relationship between the CMB, Sunyaev-Zel'dovich cluster counts, and local Hubble parameter measurements in a simple void model

    NASA Astrophysics Data System (ADS)

    Ichiki, Kiyotomo; Yoo, Chul-Moon; Oguri, Masamune

    2016-01-01

    The discrepancy between the amplitudes of matter fluctuations inferred from Sunyaev-Zel'dovich (SZ) cluster number counts and the measurement of temperature and polarization anisotropies of the cosmic microwave background (CMB) measured by the Planck satellite can be reconciled if the local universe is embedded in an underdense region as shown by Lee, 2014. Here using a simple void model assuming the open Friedmann-Robertson-Walker geometry and a Markov Chain Monte Carlo technique, we investigate how deep the local underdense region needs to be to resolve this discrepancy. Such local void, if it exists, predicts the local Hubble parameter value that is different from the global Hubble constant. We derive the posterior distribution of the local Hubble parameter from a joint fitting of the Planck CMB data and SZ cluster number counts assuming the simple void model. We show that the predicted local Hubble parameter value of Hloc=70.1 ±0.34 km s-1 Mpc-1 is in better agreement with direct local Hubble parameter measurements, indicating that the local void model may provide provide a consistent solution to the cluster number counts and Hubble parameter discrepancies.

  3. 20 CFR 666.310 - What levels of performance apply to the indicators of performance in local areas?

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... indicators of performance in local areas? 666.310 Section 666.310 Employees' Benefits EMPLOYMENT AND TRAINING... INVESTMENT ACT 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 §...

  4. 20 CFR 666.420 - Under what circumstances may a sanction be applied to local areas for poor performance?

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    .... The Governor's final decision may be appealed by the Local Board to the Secretary under 20 CFR 667.650... applied to local areas for poor performance? 666.420 Section 666.420 Employees' Benefits EMPLOYMENT AND... WORKFORCE INVESTMENT ACT Incentives and Sanctions for Local Performance § 666.420 Under what...

  5. 20 CFR 666.310 - What levels of performance apply to the indicators of performance in local areas?

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... indicators of performance in local areas? 666.310 Section 666.310 Employees' Benefits EMPLOYMENT AND TRAINING... INVESTMENT ACT 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 §...

  6. 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 §...

  7. 20 CFR 666.310 - What levels of performance apply to the indicators of performance in local areas?

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... indicators of performance in local areas? 666.310 Section 666.310 Employees' Benefits EMPLOYMENT AND TRAINING... INVESTMENT ACT 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 §...

  8. 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 §...

  9. Applying local Green's functions to study the influence of the crustal structure on hydrological loading displacements

    NASA Astrophysics Data System (ADS)

    Dill, Robert; Klemann, Volker

    2015-04-01

    The influence of the elastic Earth properties on seasonal or shorter periodic surface mass loads due to atmospheric surface pressure and terrestrial water storage variations is usually modeled by applying a local isostatic model like a homogeneous half-space model, or by a one dimensional spherical Earth model like PREM from which a unique set of elastic load Love numbers, or alternatively, elastic Green's functions are derived. The drawbacks of these strategies are that, in the first case, the response according to the local Earth structure is valid only if load and observer almost coincide, or that, in the second case, only the response of an average Earth structure is considered. However, for surface loads with horizontal scales less than 2500 km2, as for instance, for strong localized hydrological signals associated with heavy precipitation events and river floods, the Earth elastic response becomes very sensitive to inhomogeneities in the Earth crustal structure. We derive a set of local Green's functions defined for every global 1°× 1° gridcell for the 3-layer crustal structure TEA12. Local Green's functions show standard deviations of ±12% in the vertical and ±21% in the horizontal directions for distances in the range from 0.1° to 0.5°. The application of local Green's functions introduces a variability of 0.5 - 1.0 mm into the hydrological loading displacements, both in vertical and in horizontal directions. Maximum changes due to the local crustal structures are from -25% to +26% in the vertical and -91% to +55% in the horizontal displacements. In addition, the horizontal displacement changes its direction significantly, even to the opposite. The modeling of a site-dependent crustal response to surface loads provides an alternative way to probe the density and elastic structure of the Earth's crust and mantle by means of observed surface deformations caused by mass re-distributions. In addition, realistic loading models allow the monitoring of mass

  10. 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)

  11. 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. ​

  12. 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. PMID:11008426

  13. Multi-temporal MODIS-data-based PSO-FCM clustering applied to wetland extraction in the Sanjiang Plain

    NASA Astrophysics Data System (ADS)

    Liu, Hanli; Pei, Tao; Zhou, Chenghu; Zhu, A.-Xing

    2008-12-01

    In order to enhance the spectral characteristics of features for clustering, in the experiment of wetland extraction in Sanjiang Plain, we use a series of approaches in preprocessing of the MODIS remote sensing data by considering eliminating interference caused by other features. First, by analysis of the spectral characteristics of data, we choose a set of multi-temporal and multi-spectral MODIS data in Sanjiang Plain for clustering. By building and applying mask, the water areas and woodland vegetation can be eliminated from the image data. Second, by Enhanced Lee filtering and Minimum Noise Fraction (MNF) transformation, the data can be denoised and the characteristics of wetland can be enhanced obviously. After the preprocessing of data, the fuzzy c-means clustering algorithm optimized by particle swarm algorithm (PSO-FCM) is utilized on the image data for the wetland extraction. The result of experiment shows that the accuracy of wetland extraction by means of PSO-FCM algorithm is reasonable and effective.

  14. Polynomial similarity transformation theory: A smooth interpolation between coupled cluster doubles and projected BCS applied to the reduced BCS Hamiltonian

    NASA Astrophysics Data System (ADS)

    Degroote, Matthias; Henderson, Thomas M.; Zhao, Jinmo; Dukelsky, Jorge; Scuseria, Gustavo E.

    2016-03-01

    We present a similarity transformation theory based on a polynomial form of a particle-hole pair excitation operator. In the weakly correlated limit, this polynomial becomes an exponential, leading to coupled cluster doubles. In the opposite strongly correlated limit, the polynomial becomes an extended Bessel expansion and yields the projected BCS wave function. In between, we interpolate using a single parameter. The effective Hamiltonian is non-Hermitian and this polynomial similarity transformation theory follows the philosophy of traditional coupled cluster, left projecting the transformed Hamiltonian onto subspaces of the Hilbert space in which the wave function variance is forced to be zero. Similarly, the interpolation parameter is obtained through minimizing the next residual in the projective hierarchy. We rationalize and demonstrate how and why coupled cluster doubles is ill suited to the strongly correlated limit, whereas the Bessel expansion remains well behaved. The model provides accurate wave functions with energy errors that in its best variant are smaller than 1% across all interaction strengths. The numerical cost is polynomial in system size and the theory can be straightforwardly applied to any realistic Hamiltonian.

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

    PubMed Central

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

    2015-01-01

    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. PMID:26690457

  16. 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

  17. 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.

  18. 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.

  19. 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.

  20. Analysis of Binding at a Single Spatially Localized Cluster of Binding Sites by Fluorescence Recovery after Photobleaching

    PubMed Central

    Sprague, Brian L.; Müller, Florian; Pego, Robert L.; Bungay, Peter M.; Stavreva, Diana A.; McNally, James G.

    2006-01-01

    Cells contain many subcellular structures in which specialized proteins locally cluster. Binding interactions within such clusters may be analyzed in live cells using models for fluorescence recovery after photobleaching (FRAP). Here we analyze a three-dimensional FRAP model that accounts for a single spatially localized cluster of binding sites in the presence of both diffusion and impermeable boundaries. We demonstrate that models completely ignoring the spatial localization of binding yield poor estimates for the binding parameters within the binding site cluster. In contrast, we find that ignoring only the restricted axial height of the binding-site cluster is far less detrimental, thereby enabling the use of computationally less expensive models. We also identify simplified solutions to the FRAP model for limiting behaviors where either diffusion or binding dominate. We show how ignoring a role for diffusion can sometimes produce serious errors in binding parameter estimation. We illustrate application of the method by analyzing binding of a transcription factor, the glucocorticoid receptor, to a tandem array of mouse mammary tumor virus promoter sites in live cells, obtaining an estimate for an in vivo binding constant (10−7 M), and a first approximation of an upper bound on the transcription-factor residence time at the promoter (∼170 ms). These FRAP analysis tools will be important for measuring key cellular binding parameters necessary for a complete and accurate description of the networks that regulate cellular behavior. PMID:16679358

  1. 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.

  2. 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

  3. 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. PMID:11012811

  4. Applying Bayesian Maximum Entropy to extrapolating local-scale water consumption in Maricopa County, Arizona

    NASA Astrophysics Data System (ADS)

    Lee, Seung-Jae; Wentz, Elizabeth A.

    2008-01-01

    Understanding water use in the context of urban growth and climate variability requires an accurate representation of regional water use. It is challenging, however, because water use data are often unavailable, and when they are available, they are geographically aggregated to protect the identity of individuals. The present paper aims to map local-scale estimates of water use in Maricopa County, Arizona, on the basis of data aggregated to census tracts and measured only in the City of Phoenix. To complete our research goals we describe two types of data uncertainty sources (i.e., extrapolation and downscaling processes) and then generate data that account for the uncertainty sources (i.e., soft data). Our results ascertain that the Bayesian Maximum Entropy (BME) mapping method of modern geostatistics is a theoretically sound approach for assimilating the soft data into mapping processes. Our results lead to increased mapping accuracy over classical geostatistics, which does not account for the soft data. The confirmed BME maps therefore provide useful knowledge on local water use variability in the whole county that is further applied to the understanding of causal factors of urban water demand.

  5. 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.

  6. A local influence approach applied to binary data from a psychiatric study.

    PubMed

    Jansen, Ivy; Molenberghs, Geert; Aerts, Marc; Thijs, Herbert; Van Steen, Kristel

    2003-06-01

    Recently, a lot of concern has been raised about assumptions needed in order to fit statistical models to incomplete multivariate and longitudinal data. In response, research efforts are being devoted to the development of tools that assess the sensitivity of such models to often strong but always, at least in part, unverifiable assumptions. Many efforts have been devoted to longitudinal data, primarily in the selection model context, although some researchers have expressed interest in the pattern-mixture setting as well. A promising tool, proposed by Verbeke et al. (2001, Biometrics 57, 43-50), is based on local influence (Cook, 1986, Journal of the Royal Statistical Society, Series B 48, 133-169). These authors considered the Diggle and Kenward (1994, Applied Statistics 43, 49-93) model, which is based on a selection model, integrating a linear mixed model for continuous outcomes with logistic regression for dropout. In this article, we show that a similar idea can be developed for multivariate and longitudinal binary data, subject to nonmonotone missingness. We focus on the model proposed by Baker, Rosenberger, and DerSimonian (1992, Statistics in Medicine 11, 643-657). The original model is first extended to allow for (possibly continuous) covariates, whereafter a local influence strategy is developed to support the model-building process. The model is able to deal with nonmonotone missingness but has some limitations as well, stemming from the conditional nature of the model parameters. Some analytical insight is provided into the behavior of the local influence graphs. PMID:12926726

  7. Particle Swarm Optimization Applied to EEG Source Localization of Somatosensory Evoked Potentials.

    PubMed

    Shirvany, Yazdan; Mahmood, Qaiser; Edelvik, Fredrik; Jakobsson, Stefan; Hedstrom, Anders; Persson, Mikael

    2014-01-01

    One of the most important steps in presurgical diagnosis of medically intractable epilepsy is to find the precise location of the epileptogenic foci. Electroencephalography (EEG) is a noninvasive tool commonly used at epilepsy surgery centers for presurgical diagnosis. In this paper, a modified particle swarm optimization (MPSO) method is used to solve the EEG source localization problem. The method is applied to noninvasive EEG recording of somatosensory evoked potentials (SEPs) for a healthy subject. A 1 mm hexahedra finite element volume conductor model of the subject's head was generated using T1-weighted magnetic resonance imaging data. Special consideration was made to accurately model the skull and cerebrospinal fluid. An exhaustive search pattern and the MPSO method were then applied to the peak of the averaged SEP data and both identified the same region of the somatosensory cortex as the location of the SEP source. A clinical expert independently identified the expected source location, further corroborating the source analysis methods. The MPSO converged to the global minima with significantly lower computational complexity compared to the exhaustive search method that required almost 3700 times more evaluations. PMID:24122569

  8. 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

  9. Alignment of Red-Sequence Cluster Dwarf Galaxies: From the Frontier Fields to the Local Universe

    NASA Astrophysics Data System (ADS)

    Barkhouse, Wayne Alan; Archer, Haylee; Burgad, Jaford; Foote, Gregory; Rude, Cody; Lopez-Cruz, Omar

    2015-08-01

    Galaxy clusters are the largest virialized structures in the universe. Due to their high density and mass, they are an excellent laboratory for studying the environmental effects on galaxy evolution. Numerical simulations have predicted that tidal torques acting on dwarf galaxies as they fall into the cluster environment will cause the major axis of the galaxies to align with their radial position vector (a line that extends from the cluster center to the galaxy's center). We have undertaken a study to measure the redshift evolution of the alignment of red-sequence cluster dwarf galaxies based on a sample of 57 low-redshift Abell clusters imaged at KPNO using the 0.9-meter telescope, and 64 clusters from the WINGS dataset. To supplement our low-redshift sample, we have included galaxies selected from the Hubble Space Telescope Frontier fields. Leveraging the HST data allows us to look for evolutionary changes in the alignment of red-sequence cluster dwarf galaxies over a redshift range of 0 < z < 0.35. The alignment of the major axis of the dwarf galaxies is measured by fitting a Sersic function to each red-sequence galaxy using GALFIT. The quality of each model is checked visually after subtracting the model from the galaxy. The cluster sample is then combined by scaling each cluster by r200. We present our preliminary results based on the alignment of the red-sequence dwarf galaxies with: 1) the major axis of the brightest cluster galaxy, 2) the major axis of the cluster defined by the position of cluster members, and 3) a radius vector pointing from the cluster center to individual dwarf galaxies. Our combined cluster sample is sub-divided into different radial regions and redshift bins.

  10. 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

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

    PubMed

    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

  12. Stimuli-responsive surface localized ionic cluster (SLICs) formation from nonspherical colloidal particles.

    PubMed

    Lestage, David J; Urban, Marek W

    2005-07-19

    Structural features of phospholipids provide a unique opportunity for utilizing these amphiphilic species to stabilize the synthesis of colloidal dispersion particles by controlling concentration levels relative to dispersion synthesis components. 1,2-Bis(10,12-tricosadiynoyl)-sn-glycero-3-phosphocholine (DCPC) phospholipid was utilized as cosurfactant in the synthesis of sodium dioctyl sulfosuccinate (SDOSS) stabilized methyl methacrylate/n-butyl acrylate (MMA/nBA) colloidal dispersions. Aqueous dispersions containing various concentration levels of DCPC result in the formation of cocklebur particle morphologies, and when prepared in the presence of Ca2+ and annealed at various temperatures, stimuli-responsive behaviors of coalesced films were elucidated. The formation of surface localized ionic clusters (SLICs) at the film-air (F-A) and film-substrate (F-S) interfaces is shown to be responsive to concentration levels of DCPC, Ca2+/DCPC ratios, and temperature. These studies show that it is possible to control stratification and mobility to the F-A and F-S interfaces during and after coalescence. Using attenuated total reflectance Fourier transform infrared (ATR-FTIR) and internal reflection infrared imaging (IRIRI) spectroscopies, molecular entities responsible for SLIC formation were determined. These studies also show that stimuli-responsive behaviors during film formation can be controlled by colloidal solution morphologies and synergistic interactions of individual components. PMID:16008384

  13. 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.

  14. Impacts of enterotoxin gene cluster-encoded superantigens on local and systemic experimental Staphylococcus aureus infections.

    PubMed

    Nowrouzian, F L; Ali, A; Badiou, C; Dauwalder, O; Lina, G; Josefsson, E

    2015-07-01

    Staphylococcus aureus is both a component of the normal skin flora and an important pathogen. It expresses a range of recognized and putative virulence factors, such as enterotoxins with superantigenic properties. Several superantigen genes, i.e., seg, sei, selm, seln, and selo, are encoded by the enterotoxin gene cluster (egc), which is found in the majority of S. aureus isolates. Carriage of egc is associated with fitness of S. aureus in the gut microbiota, but it is not known if it contributes to pathogenicity. We constructed egc+ (functional for the seg, selm, and selo genes) and isogenic egc- S. aureus mutants, and investigated their virulence profiles in murine infection models. No effect of egc was seen in a local skin and soft tissue infection model, but in an invasive infection model, increased weight loss was observed after infection with the egc+ as compared to the egc- mutant. Mortality and arthritis were not affected by egc status. Our data suggest that egc has limited effects on the virulence of S. aureus. It may primarily function as a colonization factor increasing commensal fitness, although it might have some aggravating effects on the infection when the bacteria reach the blood. PMID:25864191

  15. 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.

  16. 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 cluster 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.

  17. 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

  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. 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.

  20. 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.

  1. A Novel Microaneurysms Detection Method Based on Local Applying of Markov Random Field.

    PubMed

    Ganjee, Razieh; Azmi, Reza; Moghadam, Mohsen Ebrahimi

    2016-03-01

    Diabetic Retinopathy (DR) is one of the most common complications of long-term diabetes. It is a progressive disease and by damaging retina, it finally results in blindness of patients. Since Microaneurysms (MAs) appear as a first sign of DR in retina, early detection of this lesion is an essential step in automatic detection of DR. In this paper, a new MAs detection method is presented. The proposed approach consists of two main steps. In the first step, the MA candidates are detected based on local applying of Markov random field model (MRF). In the second step, these candidate regions are categorized to identify the correct MAs using 23 features based on shape, intensity and Gaussian distribution of MAs intensity. The proposed method is evaluated on DIARETDB1 which is a standard and publicly available database in this field. Evaluation of the proposed method on this database resulted in the average sensitivity of 0.82 for a confidence level of 75 as a ground truth. The results show that our method is able to detect the low contrast MAs with the background while its performance is still comparable to other state of the art approaches. PMID:26779642

  2. 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

  3. 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. PMID:26896983

  4. Characterizing the local solvation environment of OH- in water clusters with AIMD

    NASA Astrophysics Data System (ADS)

    Crespo, Yanier; Hassanali, Ali

    2016-02-01

    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.

  5. Chromosomal localization and molecular characterization of three different 5S ribosomal DNA clusters in the sea urchin Paracentrotus lividus.

    PubMed

    Caradonna, Fabio; Bellavia, Daniele; Clemente, Ann Maria; Sisino, Giorgia; Barbieri, Rainer

    2007-09-01

    In this paper the chromosomal localization and molecular cloning and characterization of three 5S rDNA clusters of 700 bp (base pairs), 900 bp, and 950 bp in the sea urchin Paracentrotus lividus are reported. Southern blot hybridization demonstrated the existence of three 5S rDNA repeats of differing length in the P. lividus genome. Fluorescence in situ hybridization analysis, performed in parallel on both haploid and diploid metaphases and interphase nuclei using different 5S rDNA units as probes, localized these 5S rDNA clusters in 3 different pairs of P. lividus chromosomes. This is the first complete gene mapping not only in a sea urchin but also in the phylum of echinoderms as a whole. PMID:17893727

  6. An improved non-local means filter for denoising in brain magnetic resonance imaging based on fuzzy cluster

    NASA Astrophysics Data System (ADS)

    Liu, Bin; Sang, Xinzhu; Xing, Shujun; Wang, Bo

    2014-11-01

    Combining non-local means (NLM) filter with appropriate fuzzy cluster criterion, objective and subjective manners with synthetic brain Magnetic Resonance Imaging(MRI) are evaluated. Experimental results show that noise is effectively suppressed while image details are well kept, compared with the traditional NLM method. Meanwhile, quantitative and qualitative results indicate that artifacts are greatly reduced in our proposed method and brain MR images are typically enhanced.

  7. Star formation and black hole accretion activity in rich local clusters of galaxies

    NASA Astrophysics Data System (ADS)

    Bianconi, Matteo; Marleau, Francine R.; Fadda, Dario

    2016-04-01

    Context. We present a study of star formation and central black hole accretion activity of galaxies that are hosted in the two nearby (z ~ 0.2) rich galaxy clusters Abell 983 and 1731. Aims: We aim to quantify both the obscured and unobscured star formation rates, as well as the presence of active galactic nuclei (AGN) as a function of the environment in which the galaxy is located. Methods: We targeted the clusters with unprecedented deep infrared Spitzer observations (0.2 mJy at 24 micron), near-IR Palomar imaging and optical WIYN spectroscopy. The extent of our observations (~3 virial radii) covers the vast range of possible environments, from the very dense cluster centre to the very rarefied cluster outskirts and accretion regions. Results: The star-forming members of the two clusters present star formation rates that are comparable with those measured in coeval field galaxies. Analysis of the spatial arrangement of the spectroscopically confirmed members reveals an elongated distribution for A1731 with respect to the more uniform distribution of A983. The emerging picture is compatible with A983 being a fully evolved cluster, in contrast with the still actively accreting A1731. Conclusions: Analysis of the specific star formation rate reveals evidence of ongoing galaxy pre-processing along A1731's filament-like structure. Furthermore, the decrease in the number of star-forming galaxies and AGN towards the cluster cores suggests that the cluster environment is accelerating the ageing process of the galaxies and blocking further accretion of the cold gas that fuels both star formation and black hole accretion activity. The catalogue and the reduced images (FITS files) are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/588/A105

  8. Activity in galactic nuclei of cluster and field galaxies in the local universe

    NASA Astrophysics Data System (ADS)

    Hwang, H. S.; Park, C.; Elbaz, D.; Choi, Y.-Y.

    2012-02-01

    Aims: We study the environmental effects on the activity in galactic nuclei by comparing galaxies in clusters and in the field. Methods: Using a spectroscopic sample of galaxies in Abell clusters from the Sloan Digital Sky Survey Data Release 7, we investigate the dependence of nuclear activity on the physical parameters of clusters as well as the nearest neighbor galaxy. We also compare galaxy properties between active galactic nuclei (AGNs) hosts and non-AGN galaxies. Results: We find that the AGN fraction of early-type galaxies starts to decrease around one virial radius of clusters (r200,cl) as decreasing clustercentric radius, while that of late types starts to decrease close to the cluster center (R ~ 0.1-0.5r200,cl). The AGN fractions of early-type cluster galaxies, on average, are found to be lower than those of early-type field galaxies by a factor ~3. However, the mean AGN fractions of late-type cluster galaxies are similar to those of late-type field galaxies. The AGN fraction of early-type brightest cluster galaxies lies between those of other early-type, cluster and field galaxies with similar luminosities. In the field, the AGN fraction is strongly dependent on the morphology of and the distance to the nearest neighbor galaxy. We find an anti-correlation between the AGN fraction and the velocity dispersion of clusters for all subsamples divided by morphology and luminosity of host galaxies. The AGN power indicated by L [OIII] /MBH is found to depend strongly on the mass of host galaxies rather than the clustercentric radius. The difference in physical parameters such as luminosity, (u - r) colors, star formation rates, and (g - i) color gradients between AGN hosts and non-AGN galaxies is seen for both early and late types at all clustercentric radii, while the difference in structure parameters between the two is significant only for late types. Conclusions: These results support the idea that the activity in galactic nuclei is triggered through

  9. 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

  10. 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…

  11. Localization-Delocalization in Bridged Mixed-Valence Metal Clusters: Vibronic PKS Model Revisited.

    PubMed

    Palii, A; Tsukerblat, B; Clemente-Juan, J M; Aldoshin, S M

    2015-09-24

    Here we describe a new vibronic model of mixed valence (MV) dimer inspired by the conventional Piepho, Krausz, and Schatz (PKS) approach. We attempted to partially lift the main restriction of the PKS model dealing with the vibronically independent moieties of a MV molecule. The refined version of the PKS model in which the bridging ligands are included deals with the three main interactions: electron transfer (integral t0) related to the high-symmetric ligand configuration, on-site vibronic coupling (parameter υ) arising from the modulation of the crystal field on the metal sites by the breathing displacements of their nearest ligand surroundings, and intercenter vibronic coupling (parameter ζ) describing the dependence of the electron transfer on ligand positions in the course of their breathing movement. We apply the modified model to the analysis of the adiabatic potentials and electronic density distributions in the minima of their lower sheets for the cases of one-electron MV dimer with long and short bridges and for the two-electron MV dimer exhibiting a valence disproportionation effect. The inclusion of the intercenter interaction in addition to the conventional PKS coupling is shown to produce a strong effect on the degree of localization in MV dimers and, in particular, on the assignments to the Robin and Day classes and on the conditions of stabilization of valence disproportionated states in bielectron transfer systems. PMID:26305153

  12. Estimating the local geometry of magnetic field lines with Cluster: a theoretical discussion of physical and geometrical errors

    NASA Astrophysics Data System (ADS)

    Chanteur, Gerard

    A multi-spacecraft mission with at least four spacecraft, like CLUSTER, MMS, or Cross-Scales, can determine the local geometry of the magnetic field lines when the size of the cluster of spacecraft is small enough compared to the gradient scale lengths of the magnetic field. Shen et al. (2003) and Runov et al. (2003 and 2005) used CLUSTER data to estimate the normal and the curvature of magnetic field lines in the terrestrial current sheet: the two groups used different approaches. Reciprocal vectors of the tetrahedron formed by four spacecraft are a powerful tool for estimating gradients of fields (Chanteur, 1998 and 2000). Considering a thick and planar current sheet model and making use of the statistical properties of the reciprocal vectors allows to discuss theoretically how physical and geometrical errors affect these estimations. References Chanteur, G., Spatial Interpolation for Four Spacecraft: Theory, in Analysis Methods for Multi-Spacecraft Data, ISSI SR-001, pp. 349-369, ESA Publications Division, 1998. Chanteur, G., Accuracy of field gradient estimations by Cluster: Explanation of its dependency upon elongation and planarity of the tetrahedron, pp. 265-268, ESA SP-449, 2000. Runov, A., Nakamura, R., Baumjohann, W., Treumann, R. A., Zhang, T. L., Volwerk, M., V¨r¨s, Z., Balogh, A., Glaßmeier, K.-H., Klecker, B., R‘eme, H., and Kistler, L., Current sheet oo structure near magnetic X-line observed by Cluster, Geophys. Res. Lett., 30, 33-1, 2003. Runov, A., Sergeev, V. A., Nakamura, R., Baumjohann, W., Apatenkov, S., Asano, Y., Takada, T., Volwerk, M.,V¨r¨s, Z., Zhang, T. L., Sauvaud, J.-A., R‘eme, H., and Balogh, A., Local oo structure of the magnetotail current sheet: 2001 Cluster observations, Ann. Geophys., 24, 247-262, 2006. Shen, C., Li, X., Dunlop, M., Liu, Z. X., Balogh, A., Baker, D. N., Hapgood, M., and Wang, X., Analyses on the geometrical structure of magnetic field in the current sheet based on cluster measurements, J. Geophys. Res

  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. PMID:27019380

  14. 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…

  15. A numerically exact local solver applied to salt boundary inversion in seismic full-waveform inversion

    NASA Astrophysics Data System (ADS)

    Willemsen, Bram; Malcolm, Alison; Lewis, Winston

    2016-03-01

    In a set of problems ranging from 4-D seismic to salt boundary estimation, updates to the velocity model often have a highly localized nature. Numerical techniques for these applications such as full-waveform inversion (FWI) require an estimate of the wavefield to compute the model updates. When dealing with localized problems, it is wasteful to compute these updates in the global domain, when we only need them in our region of interest. This paper introduces a local solver that generates forward and adjoint wavefields which are, to machine precision, identical to those generated by a full-domain solver evaluated within the region of interest. This means that the local solver computes all interactions between model updates within the region of interest and the inhomogeneities in the background model outside. Because no approximations are made in the calculation of the forward and adjoint wavefields, the local solver can compute the identical gradient in the region of interest as would be computed by the more expensive full-domain solver. In this paper, the local solver is used to efficiently generate the FWI gradient at the boundary of a salt body. This gradient is then used in a level set method to automatically update the salt boundary.

  16. 20 CFR 669.555 - Do the WIA administrative cost limits for States and local areas apply to NFJP grants?

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 20 Employees' Benefits 3 2011-04-01 2011-04-01 false Do the WIA administrative cost limits for States and local areas apply to NFJP grants? 669.555 Section 669.555 Employees' Benefits EMPLOYMENT AND TRAINING ADMINISTRATION, DEPARTMENT OF LABOR NATIONAL FARMWORKER JOBS PROGRAM UNDER TITLE I OF THE WORKFORCE INVESTMENT ACT...

  17. Factor analysis and cluster analysis applied to assess the water quality of middle and lower Han River in Central China

    NASA Astrophysics Data System (ADS)

    Kuo, Yi-Ming; Liu, Wen-Wen

    2015-04-01

    The Han River basin is one of the most important industrial and grain production bases in the central China. A lot of factories and towns have been established along the river where large farmlands are located nearby. In the last few decades the water quality of the Han River, specifically in middle and lower reaches, has gradually declined. The agricultural nonpoint pollution and municipal and industrial point pollution significantly degrade the water quality of the Han River. Factor analysis can be applied to reduce the dimensionality of a data set consisting of a large number of inter-related variables. Cluster analysis can classify the samples according to their similar characters. In this study, factor analysis is used to identify major pollution indicators, and cluster analysis is employed to classify the samples based on the sample locations and hydrochemical variables. Water samples were collected from 12 sample sites collected from Xiangyang City (middle Han River) to Wuhan City (lower Han River). Correlations among 25 hydrochemical variables are statistically examined. The important pollutants are determined by factor analysis. A three-factor model is determined and explains over 85% of the total river water quality variation. Factor 1, including SS, Chl-a, TN and TP, can be considered as the nonpoint source pollution. Factor 2, including Cl-, Br-, SO42-, Ca2+, Mg2+, K+, Fe2+ and PO43-, can be treated as the industrial pollutant pollution. Factor 3, including F- and NO3-, reflects the influence of the groundwater or self-purification capability of the river water. The various land uses along the Han River correlate well with the pollution types. In addition, the result showed that the water quality of Han River deteriorated gradually from middle to lower Han River. Some tributaries have been seriously polluted and significantly influence the mainstream water quality of the Han River. Finally, the result showed that the nonpoint pollution and the point

  18. Coordination-resolved local bond contraction and electron binding-energy entrapment of Si atomic clusters and solid skins

    SciTech Connect

    Bo, Maolin; Huang, Yongli; Zhang, Ting; Wang, Yan E-mail: ecqsun@ntu.edu.sg; Zhang, Xi; Li, Can; Sun, Chang Q. E-mail: ecqsun@ntu.edu.sg

    2014-04-14

    Consistency between x-ray photoelectron spectroscopy measurements and density-function theory calculations confirms our bond order-length-strength notation-incorporated tight-binding theory predictions on the quantum entrapment of Si solid skin and atomic clusters. It has been revealed that bond-order deficiency shortens and strengthens the Si-Si bond, which results in the local densification and quantum entrapment of the core and valence electrons. Unifying Si clusters and Si(001) and (111) skins, this mechanism has led to quantification of the 2p binding energy of 96.089 eV for an isolated Si atom, and their bulk shifts of 2.461 eV. Findings evidence the significance of atomic undercoordination that is of great importance to device performance.

  19. Applying local knowledge: the contribution of oral history to wetland rehabilitation at Kanyapella Basin, Australia.

    PubMed

    Robertson, Hugh A; McGee, Tara K

    2003-11-01

    Local knowledge of the history and ecology of wetland ecosystems can be a valuable resource in wetland rehabilitation projects. This is especially the case when other historical ecological information is unavailable. As well as providing a source of historical information, time spent acquiring local knowledge can enhance public participation in environmental management and facilitate early conflict resolution between stakeholders and the community. This paper investigates the use of oral history as a tool to collate a history of the flooding, ecology and management of Kanyapella Basin, a 2581 ha wetland on the floodplain of the Murray and Goulburn Rivers, Australia. Interviews were held with nine local residents and 11 natural resource managers. Oral history proved an effective way to obtain information about changes in the frequency and distribution of flood events over the last 60 years. Observations of rare and threatened fauna, and comments regarding the success of past management were also recorded. Results from the oral history have been used to direct ecological research and develop alternative management options at Kanyapella Basin. In addition to its use in gathering ecological information, oral history also proved effective in enabling the values and concerns of local community and stakeholders to be articulated, increasing managers' understanding of the social context of the particular locality, which is fundamental to sound environmental decision-making. PMID:14580728

  20. Spatial heterogeneity of type I error for local cluster detection tests

    PubMed Central

    2014-01-01

    Background Just as power, type I error of cluster detection tests (CDTs) should be spatially assessed. Indeed, CDTs’ type I error and power have both a spatial component as CDTs both detect and locate clusters. In the case of type I error, the spatial distribution of wrongly detected clusters (WDCs) can be particularly affected by edge effect. This simulation study aims to describe the spatial distribution of WDCs and to confirm and quantify the presence of edge effect. Methods A simulation of 40 000 datasets has been performed under the null hypothesis of risk homogeneity. The simulation design used realistic parameters from survey data on birth defects, and in particular, two baseline risks. The simulated datasets were analyzed using the Kulldorff’s spatial scan as a commonly used test whose behavior is otherwise well known. To describe the spatial distribution of type I error, we defined the participation rate for each spatial unit of the region. We used this indicator in a new statistical test proposed to confirm, as well as quantify, the edge effect. Results The predefined type I error of 5% was respected for both baseline risks. Results showed strong edge effect in participation rates, with a descending gradient from center to edge, and WDCs more often centrally situated. Conclusions In routine analysis of real data, clusters on the edge of the region should be carefully considered as they rarely occur when there is no cluster. Further work is needed to combine results from power studies with this work in order to optimize CDTs performance. PMID:24885343

  1. 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. PMID:24054545

  2. 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)

  3. 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.

  4. 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.

  5. 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.

  6. 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. PMID:23951328

  7. 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.

  8. 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

  9. 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

  10. Linear coupled-cluster method. II. Analysis of local exchange-correlation potentials in beryllium and its isoelectronic series

    NASA Astrophysics Data System (ADS)

    Shankar, S.; Narasimhan, P. T.

    1984-01-01

    The Slater Xα method and its local-potential modifications are examined with reference to the many-electron exchange-correlation effects in the beryllium atom and its isoelectronic series. The linear coupled-cluster method and a hierarchy of approximations to it are employed for this purpose. The role of the exchange parameter α in providing an accurate description of the exchange-correlation effects is analyzed in the light of the electron-gas model. It is found that for Be atoms an α value of 0.768, that which causes the local potential to mimic the Hartree-Fock potential, is the best suited reference state for many-body calculations. The impact of the.α variation on the exchange-correlation corrections in the Be isoelectronic series is assessed. With increase in the nuclear charge Z, exchange-correlation corrections favor the use of α values closer to 23, the Gaspar-Kohn-Sham limit, in the Xα model. The instabilities in the cluster equations induced by ringdiagram terms are also noted. The futility of using gradient corrections to the Xα model to account for exchange-correlation effects is brought out in the calculations. It is found that a simple scaling of the electron-gas potential results in excellent single-particle reference states for many-body calculations.

  11. 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

  12. 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.

  13. Clustering Properties and Halo Masses for Central Galaxies in the Local Universe

    NASA Astrophysics Data System (ADS)

    Wang, Lixin; Li, Cheng; Jing, Y. P.

    2016-03-01

    We investigate the clustering and dark matter halo mass for a sample of ˜16,000 central galaxies selected from the SDSS/DR7 group catalog. We select subsamples of central galaxies on three two-dimensional planes, each formed by stellar mass (M{}*) and one other property out of optical color (g - r), surface stellar mass density ({μ }*), and central stellar velocity dispersion ({σ }*). For each subsample we measure both the projected cross-correlation function ({w}p({r}p)) relative to a reference galaxy sample, and an average mass of the host dark matter halos (M{}{{h}}). Both {w}p({r}p) and M{}{{h}} show the strongest dependence on M{}*, and there is no clear dependence on the other properties when M{}* is fixed. This result provides strong support to the previously adopted assumption that, for central galaxies, stellar mass is the best indicator of the host dark halo mass. For comparison we have estimated {w}p({r}p) for the full galaxy population and the population of satellite galaxies. Both populations show similar clustering properties in all cases, but they are similar to the centrals only at high masses (M{}* ≳ {10}11 {M}⊙ ). At lower masses, their {w}p({r}p) depends more strongly on {σ }* and g - r than on M{}*. It is thus necessary to consider central and satellite galaxies separately when studying the link between galaxies and dark matter halos. We discuss the implications of our results for the relative roles of halo mass and galaxy structure in quenching the star formation in central galaxies.

  14. Constraining ultracompact dwarf galaxy formation with galaxy clusters in the local universe

    NASA Astrophysics Data System (ADS)

    Pfeffer, J.; Hilker, M.; Baumgardt, H.; Griffen, B. F.

    2016-05-01

    We compare the predictions of a semi-analytic model for ultracompact dwarf galaxy (UCD) formation by tidal stripping to the observed properties of globular clusters (GCs) and UCDs in the Fornax and Virgo clusters. For Fornax we find the predicted number of stripped nuclei agrees very well with the excess number of GCs+UCDs above the GC luminosity function. GCs+UCDs with masses >107.3 M⊙ are consistent with being entirely formed by tidal stripping. Stripped nuclei can also account for Virgo UCDs with masses >107.3 M⊙ where numbers are complete by mass. For both Fornax and Virgo, the predicted velocity dispersions and radial distributions of stripped nuclei are consistent with that of UCDs within ˜50-100 kpc but disagree at larger distances where dispersions are too high and radial distributions too extended. Stripped nuclei are predicted to have radially biased anisotropies at all radii, agreeing with Virgo UCDs at clustercentric distances larger than 50 kpc. However, ongoing disruption is not included in our model which would cause orbits to become tangentially biased at small radii. We find the predicted metallicities and central black hole masses of stripped nuclei agree well with the metallicities and implied black hole masses of UCDs for masses >106.5 M⊙. The predicted black hole masses also agree well with that of M60-UCD1, the first UCD with a confirmed central black hole. These results suggest that observed GC+UCD populations are a combination of genuine GCs and stripped nuclei, with the contribution of stripped nuclei increasing towards the high-mass end.

  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. 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. PMID:14672307

  18. Fundamental and applied localized surface plasmon resonance spectroscopy studies from nanoparticle arrays to single nanoparticles

    NASA Astrophysics Data System (ADS)

    Bingham, Julia Marie

    The overarching theme of this work is to understand how the localized surface plasmon resonance (LSPR) of metallic nanoparticles can be utilized for sensing applications. The work presented here describes the use of both nanoparticle arrays and single nanoparticles. Specifically, nanoparticle arrays demonstrate sensing capabilities for inhibin A, prostate specific antigen (PSA), gas and vapors, and the dye, Nile Red. A new wide-field imaging apparatus is developed to characterize multiple single nanoparticles simultaneously as well as correlate the nanoparticle structural details using transmission electron microscopy (TEM), ultimately to develop single nanoparticle sensors. From these studies, LSPR spectroscopy is shown to be a valuable tool for sensor development. In the studies utilizing nanoparticle arrays, LSPR spectroscopy proves to be a feasible technique to detect inhibin A and PSA using a sandwich assay format. However, binding constants are determined to be several orders of magnitude lower than expected for PSA. It is hypothesized that the method to immobilize the capture antibody affected the affinity for PSA. Using a high resolution LSPR spectrometer, gas and vapor sensing on the basis of small refractive index (RI) changes is demonstrated. Nile Red is used to investigate the interaction between the polarity-dependent dye absorbance and the RI dependent LSPR of Ag nanoparticles. A wide-field LSPR imaging method using a liquid crystal tunable filter is used to measure the scattering spectra of multiple Ag nanoparticles in parallel and the RI response of multiple single nanoparticles is determined. This method also provides the ability to characterize moving Ag nanoparticles by measuring the scattering spectra of the particles while simultaneously tracking their motion. Consequently, single particle diffusion coefficients are determined. As an example, several single Ag nanoprisms are tracked, the LSPR scattering spectrum of each moving particle is

  19. Local and regional components of aerosol in a heavily trafficked street canyon in central London derived from PMF and cluster analysis of single-particle ATOFMS spectra.

    PubMed

    Giorio, Chiara; Tapparo, Andrea; Dall'Osto, Manuel; Beddows, David C S; Esser-Gietl, Johanna K; Healy, Robert M; Harrison, Roy M

    2015-03-17

    Positive matrix factorization (PMF) has been applied to single particle ATOFMS spectra collected on a six lane heavily trafficked road in central London (Marylebone Road), which well represents an urban street canyon. PMF analysis successfully extracted 11 factors from mass spectra of about 700,000 particles as a complement to information on particle types (from K-means cluster analysis). The factors were associated with specific sources and represent the contribution of different traffic related components (i.e., lubricating oils, fresh elemental carbon, organonitrogen and aromatic compounds), secondary aerosol locally produced (i.e., nitrate, oxidized organic aerosol and oxidized organonitrogen compounds), urban background together with regional transport (aged elemental carbon and ammonium) and fresh sea spray. An important result from this study is the evidence that rapid chemical processes occur in the street canyon with production of secondary particles from road traffic emissions. These locally generated particles, together with aging processes, dramatically affected aerosol composition producing internally mixed particles. These processes may become important with stagnant air conditions and in countries where gasoline vehicles are predominant and need to be considered when quantifying the impact of traffic emissions. PMID:25695365

  20. 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

  1. Structural skeleton of preferentially interpenetrated clusters and correlation with shear localization in Mg-Cu-Ni ternary metallic glasses.

    PubMed

    Wang, Q; Li, J H; Liu, J B; Liu, B X

    2014-09-28

    Inherent hierarchical structure and its effect on shear localization were clarified for ternary Mg-Cu-Ni metallic glasses via molecular dynamics studies based on a newly constructed n-body potential for the system. Assisted by a proposed index to detect the medium-range correlation heterogeneity, it was found that the Cu/Ni-centered icosahedra and specific Mg-centered clusters exhibit a strong preference to interconnect, leading to the formation, over an extended scale, of a percolated network that serves as structural skeleton in the glassy matrix. In constituting the skeleton network, the clusters mainly integrate in an interpenetrating mode, while the noninterpenetrating linkages provide additional reinforcements, jointly consolidating the structural and energetic stability of the skeleton. Furthermore, by monitoring the structural evolution upon compressive deformation, it was revealed that the gradual collapse of the skeleton network is intimately correlated to the mechanical response of metallic glasses and acts as a structural signature of the initiation and propagation of shear bands. PMID:25110190

  2. Comparing Local and High-z X-ray Galaxy Clusters: Properties of the Gas Mass Fraction, Metallicity, and Entropy

    NASA Astrophysics Data System (ADS)

    Ettori, S.; Tozzi, P.; Rosati, P.

    We summarize here some of the results on the properties of the X-ray emitting plasma in galaxy clusters at high redshift that we present and discuss in a series of papers (Ettori, Tozzi & Rosati 2003a; Tozzi et al. 2003; Rosati et al. 2003; Ettori et al. 2003b). In particular, we report on (1) how the gas mass fraction measured in galaxy clusters at z>0.7 is used to put significant constraints on the cosmological parameters in a independent and complementary way with respect to the power spectrum of the observed anisotropies in the Cosmic Microwave Background and the magnitude-redshift relation for distant type Ia supernovae (Ettori et al. 2003a), (2) what is the measured metallicity of the intracluster medium at redshift between 0.3 and 1.3 (Tozzi et al. 2003, Rosati et al. 2003), (3) how the observed entropy values in the cores of these high-z systems compare with local estimates (Ettori et al. 2003b).

  3. Localization and mapping of CO/sub 2/ fixation genes within two gene clusters in Rhodobacter sphaeroides

    SciTech Connect

    Gibson, J.L.; Tabita, F.R.

    1988-05-01

    Two fructose 1,6-bisphosphatase structural genes (fbpA and fbpB) have been identified within two unlinked gene clusters that were previously shown to contain the Rhodobacter sphaeroides sequences that code form I and form II ribulose 1,5-bisphosphate carboxylase-oxygenase and phosphoribulokinase. The fbpA and fbpB genes were localized to a region immediately upstream from the corresponding prkA and prkB sequences and were found to be transcribed in the same direction as the phosphoribulokinase and ribulose 1,5-bisphosphate carboxylase-oxygenase genes based on inducible expression of fructose 1,6-bisphosphatase activity directed by the lac promoter. A recombinant plasmid was constructed that contained the tandem fbpA and prkA genes inserted downstream from the lac promoter in plasmid pUC18. Both gene products were expressed in Escherichia coli upon induction of transcription with isopropyl ..beta..-D-thiogalactoside, demonstrating that the two genes can be cotranscribed. A Zymomonas mobilis glyceraldehyde 3-phosphate-dehydrogenase gene (gap) hybridized to a DNA sequence located approximately 1 kilobase upstream from the form II ribulose 1,5-bisphosphate carboxylase-oxygenase gene. Although no corresponding gap sequence was found within the form I gene cluster, an additional region of homology was detected immediately upstream from the sequences that encode the form I and form II ribulose 1,5-bisphosphate carboxylase-oxygenases.

  4. Structural Variants in the Soybean Genome Localize to Clusters of Biotic Stress-Response Genes1[W][OA

    PubMed Central

    McHale, Leah K.; Haun, William J.; Xu, Wayne W.; Bhaskar, Pudota B.; Anderson, Justin E.; Hyten, David L.; Gerhardt, Daniel J.; Jeddeloh, Jeffrey A.; Stupar, Robert M.

    2012-01-01

    Genome-wide structural and gene content variations are hypothesized to drive important phenotypic variation within a species. Structural and gene content variations were assessed among four soybean (Glycine max) genotypes using array hybridization and targeted resequencing. Many chromosomes exhibited relatively low rates of structural variation (SV) among genotypes. However, several regions exhibited both copy number and presence-absence variation, the most prominent found on chromosomes 3, 6, 7, 16, and 18. Interestingly, the regions most enriched for SV were specifically localized to gene-rich regions that harbor clustered multigene families. The most abundant classes of gene families associated with these regions were the nucleotide-binding and receptor-like protein classes, both of which are important for plant biotic defense. The colocalization of SV with plant defense response signal transduction pathways provides insight into the mechanisms of soybean resistance gene evolution and may inform the development of new approaches to resistance gene cloning. PMID:22696021

  5. 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.

  6. Identification of the local vibrational modes of small nitrogen clusters in dilute GaAsN

    NASA Astrophysics Data System (ADS)

    Carvalho, A.; Barker, S. J.; Jones, R.; Williams, R. S.; Ashwin, M. J.; Newman, R. C.; Stavrinou, P. N.; Parry, G.; Jones, T. S.; Öberg, S.; Briddon, P. R.

    2007-12-01

    Ultra-high-resolution infra-red local vibrational mode (IR LVM) spectroscopy measurements together with density-functional calculations have been used to identify the signatures of close substitutional nitrogen ( NAs) pairs in GaAs1-xNx alloys with concentrations of x<0.025. We show that the presence of sub-peaks close to the NAs absorption band can be attributed to nitrogen pairs up to fourth neighbor position. Additionally, we suggest that the nitrogen pairs which give rise to the deepest levels below the conduction band edge are the first to be removed upon annealing.

  7. 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.

  8. Fine genetic mapping localizes cucumber scab resistance gene Ccu into an R gene cluster.

    PubMed

    Kang, Houxiang; Weng, Yiqun; Yang, Yuhong; Zhang, Zhonghua; Zhang, Shengping; Mao, Zhenchuan; Cheng, Guohua; Gu, Xingfang; Huang, Sanwen; Xie, Bingyan

    2011-03-01

    Scab, caused by Cladosporium cucumerinum, is an important disease of cucumber, Cucumis sativus. In this study, we conducted fine genetic mapping of the single dominant scab resistance gene, Ccu, with 148 F(9) recombinant inbred lines (RILs) and 1,944 F(2) plants derived from the resistant cucumber inbred line 9110Gt and the susceptible line 9930, whose draft genome sequence is now available. A framework linkage map was first constructed with simple sequence repeat markers placing Ccu into the terminal 670 kb region of cucumber Chromosome 2. The 9110Gt genome was sequenced at 5× genome coverage with the Solexa next-generation sequencing technology. Sequence analysis of the assembled 9110Gt contigs and the Ccu region of the 9930 genome identified three insertion/deletion (Indel) markers, Indel01, Indel02, and Indel03 that were closely linked with the Ccu locus. On the high-resolution map developed with the F(2) population, the two closest flanking markers, Indel01 and Indel02, were 0.14 and 0.15 cM away from the target gene Ccu, respectively, and the physical distance between the two markers was approximately 140 kb. Detailed annotation of the 180 kb region harboring the Ccu locus identified a cluster of six resistance gene analogs (RGAs) that belong to the nucleotide binding site (NBS) type R genes. Four RGAs were in the region delimited by markers Indel01 and Indel02, and thus were possible candidates of Ccu. Comparative DNA analysis of this cucumber Ccu gene region with a melon (C. melo) bacterial artificial chromosome (BAC) clone revealed a high degree of micro-synteny and conservation of the RGA tandem repeats in this region. PMID:21104067

  9. Effect of pre-exercise phototherapy applied with different cluster probe sizes on elbow flexor muscle fatigue.

    PubMed

    Rossato, Mateus; Dellagrana, Rodolfo A; Lanferdini, Fábio J; Sakugawa, Raphael L; Lazzari, Caetano D; Baroni, Bruno M; Diefenthaeler, Fernando

    2016-08-01

    Phototherapy has been used for reducing muscle fatigue. In view of the various types of phototherapy cluster probes available in the market, the purpose of this study was to compare the effects of a similar phototherapy dosage with two different cluster probes on elbow flexor muscle fatigue: small cluster probe (SC = 9 diodes; 7.5 cm(2)) vs. large cluster probe (LC = 33 diodes; 30.2 cm(2)). Ten physically active male aged 18-35 years participate in a randomized, crossover, double-blind, placebo-controlled trial, which each participant was submitted to the same testing protocol in four sessions (separated by at least 48 h) with different treatments: LC-phototherapy, SC-phototherapy, LC-placebo, and SC-placebo. The elbow flexion maximal isometric voluntary contraction (MIVC) was performed before and after a fatigue protocol (60 % of MIVC until exhaustion). Electromyography (EMG) of the biceps brachii muscle was collected during all testing procedure. Phototherapy with dose of 60 J per muscle [LC: 33 diodes = 5 lasers (850 nm), 12 LEDs (670 nm), 8 LEDs (880 nm), and 8 LEDs (950 nm); SC: 9 diodes = 5 lasers (850 nm) and 4 LEDs (670 nm)] or placebo applications occurred before fatigue protocol. Two-way ANOVA (treatment and time factors) and one-way ANOVA were used, followed by LSD post hoc. Time to exhaustion was significantly higher in active LC (15 %; p = 0.031) and SC (14 %; p = 0.038) in comparison with their respective placebo treatments, without differences between LC and SC (p > 0.05) or between placebo conditions (p > 0.05). This larger exercise tolerance in phototherapy conditions was not accompanied by a higher decrement in the volunteers' maximal strength capacity (11-15 %; p > 0.05 for all). EMG signals presented no difference between the four condition tested here. In both large and small cluster probes (according parameters tested in this study) led to reduced fatigue in elbow flexor muscles, without

  10. Precise localization of m6A in Rous sarcoma virus RNA reveals clustering of methylation sites: implications for RNA processing.

    PubMed

    Kane, S E; Beemon, K

    1985-09-01

    N6-methyladenosine (m6A) residues are present as internal base modifications in most higher eucaryotic mRNAs; however, the biological function of this modification is not known. We describe a method for localizing and quantitating m6A within a large RNA molecule, the genomic RNA of Rous sarcoma virus. Specific fragments of 32P-labeled Rous sarcoma virus RNA were isolated by hybridization with complementary DNA restriction fragments spanning nucleotides 6185 to 8050. RNA was digested with RNase and finger-printed, and individual oligonucleotides were analyzed for the presence of m6A by paper electrophoresis and thin-layer chromatography. With this technique, seven sites of methylation in this region of the Rous sarcoma virus genome were localized at nucleotides 6394, 6447, 6507, 6718, 7414, 7424, and 8014. Further, m6A was observed at two additional sites whose nucleotide assignments remain ambiguous. A clustering of two or more m6A residues was seen at three positions within the RNA analyzed. Modification at certain sites was found to be heterogeneous, in that different molecules of RNA appeared to be methylated differently. Previous studies have determined that methylation occurs only in the sequences Gm6AC and Am6AC. We observed a high frequency of methylation at PuGm6ACU sequences. The possible involvement of m6A in RNA splicing events is discussed. PMID:3016525