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Sample records for signals statistical mapping

  1. Controlling False Discovery Rate in Signal Space for Transformation-Invariant Thresholding of Statistical Maps.

    PubMed

    Li, Junning; Shi, Yonggang; Toga, Arthur W

    2015-01-01

    Thresholding statistical maps with appropriate correction of multiple testing remains a critical and challenging problem in brain mapping. Since the false discovery rate (FDR) criterion was introduced to the neuroimaging community a decade ago, various improvements have been proposed. However, a highly desirable feature, transformation invariance, has not been adequately addressed, especially for voxel-based FDR. Thresholding applied after spatial transformation is not necessarily equivalent to transformation applied after thresholding in the original space. We find this problem closely related to another important issue: spatial correlation of signals. A Gaussian random vector-valued image after normalization is a random map from a Euclidean space to a high-dimension unit-sphere. Instead of defining the FDR measure in the image's Euclidean space, we define it in the signals' hyper-spherical space whose measure not only reflects the intrinsic "volume" of signals' randomness but also keeps invariant under images' spatial transformation. Experiments with synthetic and real images demonstrate that our method achieves transformation invariance and significantly minimizes the bias introduced by the choice of template images.

  2. The Statistical Value of Raw Fluorescence Signal in Luminex xMAP Based Multiplex Immunoassays

    PubMed Central

    Breen, Edmond J.; Tan, Woei; Khan, Alamgir

    2016-01-01

    Tissue samples (plasma, saliva, serum or urine) from 169 patients classified as either normal or having one of seven possible diseases are analysed across three 96-well plates for the presences of 37 analytes using cytokine inflammation multiplexed immunoassay panels. Censoring for concentration data caused problems for analysis of the low abundant analytes. Using fluorescence analysis over concentration based analysis allowed analysis of these low abundant analytes. Mixed-effects analysis on the resulting fluorescence and concentration responses reveals a combination of censoring and mapping the fluorescence responses to concentration values, through a 5PL curve, changed observed analyte concentrations. Simulation verifies this, by showing a dependence on the mean florescence response and its distribution on the observed analyte concentration levels. Differences from normality, in the fluorescence responses, can lead to differences in concentration estimates and unreliable probabilities for treatment effects. It is seen that when fluorescence responses are normally distributed, probabilities of treatment effects for fluorescence based t-tests has greater statistical power than the same probabilities from concentration based t-tests. We add evidence that the fluorescence response, unlike concentration values, doesn’t require censoring and we show with respect to differential analysis on the fluorescence responses that background correction is not required. PMID:27243383

  3. Plague Maps and Statistics

    MedlinePlus

    ... and Statistics Recommend on Facebook Tweet Share Compartir Plague in the United States Plague was first introduced ... per year in the United States: 1900-2012. Plague Worldwide Plague epidemics have occurred in Africa, Asia, ...

  4. Concept Maps in Introductory Statistics

    ERIC Educational Resources Information Center

    Witmer, Jeffrey A.

    2016-01-01

    Concept maps are tools for organizing thoughts on the main ideas in a course. I present an example of a concept map that was created through the work of students in an introductory class and discuss major topics in statistics and relationships among them.

  5. Statistical methods in physical mapping

    SciTech Connect

    Nelson, D.O.

    1995-05-01

    One of the great success stories of modern molecular genetics has been the ability of biologists to isolate and characterize the genes responsible for serious inherited diseases like fragile X syndrome, cystic fibrosis and myotonic muscular dystrophy. This dissertation concentrates on constructing high-resolution physical maps. It demonstrates how probabilistic modeling and statistical analysis can aid molecular geneticists in the tasks of planning, execution, and evaluation of physical maps of chromosomes and large chromosomal regions. The dissertation is divided into six chapters. Chapter 1 provides an introduction to the field of physical mapping, describing the role of physical mapping in gene isolation and ill past efforts at mapping chromosomal regions. The next two chapters review and extend known results on predicting progress in large mapping projects. Such predictions help project planners decide between various approaches and tactics for mapping large regions of the human genome. Chapter 2 shows how probability models have been used in the past to predict progress in mapping projects. Chapter 3 presents new results, based on stationary point process theory, for progress measures for mapping projects based on directed mapping strategies. Chapter 4 describes in detail the construction of all initial high-resolution physical map for human chromosome 19. This chapter introduces the probability and statistical models involved in map construction in the context of a large, ongoing physical mapping project. Chapter 5 concentrates on one such model, the trinomial model. This chapter contains new results on the large-sample behavior of this model, including distributional results, asymptotic moments, and detection error rates. In addition, it contains an optimality result concerning experimental procedures based on the trinomial model. The last chapter explores unsolved problems and describes future work.

  6. Applications of statistics to thematic mapping.

    USGS Publications Warehouse

    Rosenfield, G.H.; Melley, M.L.

    1980-01-01

    Two statistical problems occurring in the effort to analyze thematic maps and mapping are determining the accuracy of thematic content and comparing factors studied in thematic mapping. Statistical procedures applicable to thematic mapping involve sampling, determining accuracy, and comparing factors. A sampling procedure using an unaligned pattern within a square grid network is applicable for use with thematic maps. Sample size may be determined using the binomial distribution based upon the confidence interval to define the true mean of the population within certain limits. The confidence interval may also be used to define the upper and lower limits of the accuracy of the thematic map. - from Authors

  7. Statistical and computational challenges in physical mapping

    SciTech Connect

    Nelson, D.O.; Speed, T.P.

    1994-06-01

    One of the great success stories of modern molecular genetics has been the ability of biologists to isolate and characterize the genes responsible for serious inherited diseases like Huntington`s disease, cystic fibrosis, and myotonic dystrophy. Instrumental in these efforts has been the construction of so-called {open_quotes}physical maps{close_quotes} of large regions of human chromosomes. Constructing a physical map of a chromosome presents a number of interesting challenges to the computational statistician. In addition to the general ill-posedness of the problem, complications include the size of the data sets, computational complexity, and the pervasiveness of experimental error. The nature of the problem and the presence of many levels of experimental uncertainty make statistical approaches to map construction appealing. Simultaneously, however, the size and combinatorial complexity of the problem make such approaches computationally demanding. In this paper we discuss what physical maps are and describe three different kinds of physical maps, outlining issues which arise in constructing them. In addition, we describe our experience with powerful, interactive statistical computing environments. We found that the ability to create high-level specifications of proposed algorithms which could then be directly executed provided a flexible rapid prototyping facility for developing new statistical models and methods. The ability to check the implementation of an algorithm by comparing its results to that of an executable specification enabled us to rapidly debug both specification and implementation in an environment of changing needs.

  8. Statistical mapping of count survey data

    USGS Publications Warehouse

    Royle, J. Andrew; Link, W.A.; Sauer, J.R.; Scott, J. Michael; Heglund, Patricia J.; Morrison, Michael L.; Haufler, Jonathan B.; Wall, William A.

    2002-01-01

    We apply a Poisson mixed model to the problem of mapping (or predicting) bird relative abundance from counts collected from the North American Breeding Bird Survey (BBS). The model expresses the logarithm of the Poisson mean as a sum of a fixed term (which may depend on habitat variables) and a random effect which accounts for remaining unexplained variation. The random effect is assumed to be spatially correlated, thus providing a more general model than the traditional Poisson regression approach. Consequently, the model is capable of improved prediction when data are autocorrelated. Moreover, formulation of the mapping problem in terms of a statistical model facilitates a wide variety of inference problems which are cumbersome or even impossible using standard methods of mapping. For example, assessment of prediction uncertainty, including the formal comparison of predictions at different locations, or through time, using the model-based prediction variance is straightforward under the Poisson model (not so with many nominally model-free methods). Also, ecologists may generally be interested in quantifying the response of a species to particular habitat covariates or other landscape attributes. Proper accounting for the uncertainty in these estimated effects is crucially dependent on specification of a meaningful statistical model. Finally, the model may be used to aid in sampling design, by modifying the existing sampling plan in a manner which minimizes some variance-based criterion. Model fitting under this model is carried out using a simulation technique known as Markov Chain Monte Carlo. Application of the model is illustrated using Mourning Dove (Zenaida macroura) counts from Pennsylvania BBS routes. We produce both a model-based map depicting relative abundance, and the corresponding map of prediction uncertainty. We briefly address the issue of spatial sampling design under this model. Finally, we close with some discussion of mapping in relation to

  9. Spectral Kurtosis statistics of transient signals

    NASA Astrophysics Data System (ADS)

    Nita, G. M.

    2016-05-01

    We obtain analytical approximations for the expectation and variance of the Spectral Kurtosis estimator in the case of Gaussian and coherent transient time domain signals mixed with a quasi-stationary Gaussian background, which are suitable for practical estimations of their signal-to-noise ratio and duty-cycle relative to the instrumental integration time. We validate these analytical approximations by means of numerical simulations and demonstrate that such estimates are affected by statistical uncertainties that, for a suitable choice of the integration time, may not exceed a few per cent. Based on these analytical results, we suggest a multiscale Spectral Kurtosis spectrometer design optimized for real-time detection of transient signals, automatic discrimination based on their statistical signature, and measurement of their properties.

  10. Statistics over features: EEG signals analysis.

    PubMed

    Derya Ubeyli, Elif

    2009-08-01

    This paper presented the usage of statistics over the set of the features representing the electroencephalogram (EEG) signals. Since classification is more accurate when the pattern is simplified through representation by important features, feature extraction and selection play an important role in classifying systems such as neural networks. Multilayer perceptron neural network (MLPNN) architectures were formulated and used as basis for detection of electroencephalographic changes. Three types of EEG signals (EEG signals recorded from healthy volunteers with eyes open, epilepsy patients in the epileptogenic zone during a seizure-free interval, and epilepsy patients during epileptic seizures) were classified. The selected Lyapunov exponents, wavelet coefficients and the power levels of power spectral density (PSD) values obtained by eigenvector methods of the EEG signals were used as inputs of the MLPNN trained with Levenberg-Marquardt algorithm. The classification results confirmed that the proposed MLPNN has potential in detecting the electroencephalographic changes. PMID:19555931

  11. Statistical Diagnostics to Identify Galactic Foregrounds in B -Mode Maps

    NASA Astrophysics Data System (ADS)

    Kamionkowski, Marc; Kovetz, Ely D.

    2014-11-01

    Recent developments in the search for inflationary gravitational waves in the cosmic microwave background polarization motivate the search for new diagnostics to distinguish the Galactic foreground contribution to B modes from the cosmic signal. We show that B modes from these foregrounds should exhibit a local hexadecapolar departure in power from statistical isotropy (SI). We present a simple algorithm to search for a uniform SI violation of this sort, as may arise in a sufficiently small patch of sky. We then show how to search for these effects if the orientation of the SI violation varies across the survey region, as is more likely to occur in surveys with more sky coverage. If detected, these departures from Gaussianity would indicate some level of Galactic foreground contamination in the B -mode maps. Given uncertainties about foreground properties, though, caution should be exercised in attributing a null detection to an absence of foregrounds.

  12. Geometry of basic statistical physics mapping

    NASA Astrophysics Data System (ADS)

    Angelelli, Mario; Konopelchenko, Boris

    2016-09-01

    The geometry of hypersurfaces defined by the relation which generalizes the classical formula for free energy in terms of microstates is studied. The induced metric, the Riemann curvature tensor, the Gauss-Kronecker curvature and its associated entropy are calculated. A special class of ideal statistical hypersurfaces is analyzed in detail. Non-ideal hypersurfaces and singularities similar to those of the phase transitions are considered. The tropical limit of the statistical hypersurfaces and the double scaling tropical limit are discussed too.

  13. Geometry of basic statistical physics mapping

    NASA Astrophysics Data System (ADS)

    Angelelli, Mario; Konopelchenko, Boris

    2016-09-01

    The geometry of hypersurfaces defined by the relation which generalizes the classical formula for free energy in terms of microstates is studied. The induced metric, the Riemann curvature tensor, the Gauss–Kronecker curvature and its associated entropy are calculated. A special class of ideal statistical hypersurfaces is analyzed in detail. Non-ideal hypersurfaces and singularities similar to those of the phase transitions are considered. The tropical limit of the statistical hypersurfaces and the double scaling tropical limit are discussed too.

  14. Maximally Informative Statistics for Localization and Mapping

    NASA Technical Reports Server (NTRS)

    Deans, Matthew C.

    2001-01-01

    This paper presents an algorithm for localization and mapping for a mobile robot using monocular vision and odometry as its means of sensing. The approach uses the Variable State Dimension filtering (VSDF) framework to combine aspects of Extended Kalman filtering and nonlinear batch optimization. This paper describes two primary improvements to the VSDF. The first is to use an interpolation scheme based on Gaussian quadrature to linearize measurements rather than relying on analytic Jacobians. The second is to replace the inverse covariance matrix in the VSDF with its Cholesky factor to improve the computational complexity. Results of applying the filter to the problem of localization and mapping with omnidirectional vision are presented.

  15. Statistical graphics: mapping the pathways of science.

    PubMed

    Wainer, H; Velleman, P F

    2001-01-01

    This chapter traces the evolution of statistical graphics starting with its departure from the common noun structure of Cartesian determinism, through William Playfair's revolutionary grammatical shift to graphs as proper nouns, and alights on the modern conception of graph as an active participant in the scientific process of discovery. The ubiquitous availability of data, software, and cheap, high-powered, computing when coupled with the broad acceptance of the ideas in Tukey's 1977 treatise on exploratory data analysis has yielded a fundamental change in the way that the role of statistical graphics is thought of within science-as a dynamic partner and guide to the future rather than as a static monument to the discoveries of the past. We commemorate and illustrate this development while pointing readers to the new tools available and providing some indications of their potential.

  16. Efficient statistical mapping of avian count data

    USGS Publications Warehouse

    Royle, J. Andrew; Wikle, C.K.

    2005-01-01

    We develop a spatial modeling framework for count data that is efficient to implement in high-dimensional prediction problems. We consider spectral parameterizations for the spatially varying mean of a Poisson model. The spectral parameterization of the spatial process is very computationally efficient, enabling effective estimation and prediction in large problems using Markov chain Monte Carlo techniques. We apply this model to creating avian relative abundance maps from North American Breeding Bird Survey (BBS) data. Variation in the ability of observers to count birds is modeled as spatially independent noise, resulting in over-dispersion relative to the Poisson assumption. This approach represents an improvement over existing approaches used for spatial modeling of BBS data which are either inefficient for continental scale modeling and prediction or fail to accommodate important distributional features of count data thus leading to inaccurate accounting of prediction uncertainty.

  17. Reliability of groundwater vulnerability maps obtained through statistical methods.

    PubMed

    Sorichetta, Alessandro; Masetti, Marco; Ballabio, Cristiano; Sterlacchini, Simone; Beretta, Giovanni Pietro

    2011-04-01

    Statistical methods are widely used in environmental studies to evaluate natural hazards. Within groundwater vulnerability in particular, statistical methods are used to support decisions about environmental planning and management. The production of vulnerability maps obtained by statistical methods can greatly help decision making. One of the key points in all of these studies is the validation of the model outputs, which is performed through the application of various techniques to analyze the quality and reliability of the final results and to evaluate the model having the best performance. In this study, a groundwater vulnerability assessment to nitrate contamination was performed for the shallow aquifer located in the Province of Milan (Italy). The Weights of Evidence modeling technique was used to generate six model outputs, each one with a different number of input predictive factors. Considering that a vulnerability map is meaningful and useful only if it represents the study area through a limited number of classes with different degrees of vulnerability, the spatial agreement of different reclassified maps has been evaluated through the kappa statistics and a series of validation procedures has been proposed and applied to evaluate the reliability of the reclassified maps. Results show that performance is not directly related to the number of input predictor factors and that is possible to identify, among apparently similar maps, those best representing groundwater vulnerability in the study area. Thus, vulnerability maps generated using statistical modeling techniques have to be carefully handled before they are disseminated. Indeed, the results may appear to be excellent and final maps may perform quite well when, in fact, the depicted spatial distribution of vulnerability is greatly different from the actual one. For this reason, it is necessary to carefully evaluate the obtained results using multiple statistical techniques that are capable of

  18. Statistical properties of the universal limit map of grazing bifurcations

    NASA Astrophysics Data System (ADS)

    Li, Denghui; Chen, Hebai; Xie, Jianhua

    2016-09-01

    In this paper, the statistical properties of an interval map, having a square-root singular point which characterizes grazing bifurcations of impact oscillators, are studied. Firstly, we show that in some parameter regions the map admits an induced Markov structure with an exponential decay tail of the return times. Then we prove that the map has a unique mixing absolutely continuous invariant probability measure. Finally, by applying the Markov tower method, we prove that exponential decay of correlations and the central limit theorem hold for Hölder continuous observations.

  19. Mapping the results of local statistics: Using geographically weighted regression

    PubMed Central

    Matthews, Stephen A.; Yang, Tse-Chuan

    2014-01-01

    The application of geographically weighted regression (GWR) – a local spatial statistical technique used to test for spatial nonstationarity – has grown rapidly in the social, health and demographic sciences. GWR is a useful exploratory analytical tool that generates a set of location-specific parameter estimates which can be mapped and analysed to provide information on spatial nonstationarity in relationships between predictors and the outcome variable. A major challenge to GWR users, however, is how best to map these parameter estimates. This paper introduces a simple mapping technique that combines local parameter estimates and local t-values on one map. The resultant map can facilitate the exploration and interpretation of nonstationarity. PMID:25578024

  20. The standard map: From Boltzmann-Gibbs statistics to Tsallis statistics

    NASA Astrophysics Data System (ADS)

    Tirnakli, Ugur; Borges, Ernesto P.

    2016-03-01

    As well known, Boltzmann-Gibbs statistics is the correct way of thermostatistically approaching ergodic systems. On the other hand, nontrivial ergodicity breakdown and strong correlations typically drag the system into out-of-equilibrium states where Boltzmann-Gibbs statistics fails. For a wide class of such systems, it has been shown in recent years that the correct approach is to use Tsallis statistics instead. Here we show how the dynamics of the paradigmatic conservative (area-preserving) stan-dard map exhibits, in an exceptionally clear manner, the crossing from one statistics to the other. Our results unambiguously illustrate the domains of validity of both Boltzmann-Gibbs and Tsallis statistical distributions. Since various important physical systems from particle confinement in magnetic traps to autoionization of molecular Rydberg states, through particle dynamics in accelerators and comet dynamics, can be reduced to the standard map, our results are expected to enlighten and enable an improved interpretation of diverse experimental and observational results.

  1. The standard map: From Boltzmann-Gibbs statistics to Tsallis statistics.

    PubMed

    Tirnakli, Ugur; Borges, Ernesto P

    2016-03-23

    As well known, Boltzmann-Gibbs statistics is the correct way of thermostatistically approaching ergodic systems. On the other hand, nontrivial ergodicity breakdown and strong correlations typically drag the system into out-of-equilibrium states where Boltzmann-Gibbs statistics fails. For a wide class of such systems, it has been shown in recent years that the correct approach is to use Tsallis statistics instead. Here we show how the dynamics of the paradigmatic conservative (area-preserving) stan-dard map exhibits, in an exceptionally clear manner, the crossing from one statistics to the other. Our results unambiguously illustrate the domains of validity of both Boltzmann-Gibbs and Tsallis statistical distributions. Since various important physical systems from particle confinement in magnetic traps to autoionization of molecular Rydberg states, through particle dynamics in accelerators and comet dynamics, can be reduced to the standard map, our results are expected to enlighten and enable an improved interpretation of diverse experimental and observational results.

  2. SUBMILLIMETER NUMBER COUNTS FROM STATISTICAL ANALYSIS OF BLAST MAPS

    SciTech Connect

    Patanchon, Guillaume; Ade, Peter A. R.; Griffin, Matthew; Hargrave, Peter C.; Mauskopf, Philip; Moncelsi, Lorenzo; Pascale, Enzo; Bock, James J.; Chapin, Edward L.; Halpern, Mark; Marsden, Gaelen; Scott, Douglas; Devlin, Mark J.; Dicker, Simon R.; Klein, Jeff; Rex, Marie; Gundersen, Joshua O.; Hughes, David H.; Netterfield, Calvin B.; Olmi, Luca

    2009-12-20

    We describe the application of a statistical method to estimate submillimeter galaxy number counts from confusion-limited observations by the Balloon-borne Large Aperture Submillimeter Telescope (BLAST). Our method is based on a maximum likelihood fit to the pixel histogram, sometimes called 'P(D)', an approach which has been used before to probe faint counts, the difference being that here we advocate its use even for sources with relatively high signal-to-noise ratios. This method has an advantage over standard techniques of source extraction in providing an unbiased estimate of the counts from the bright end down to flux densities well below the confusion limit. We specifically analyze BLAST observations of a roughly 10 deg{sup 2} map centered on the Great Observatories Origins Deep Survey South field. We provide estimates of number counts at the three BLAST wavelengths 250, 350, and 500 mum; instead of counting sources in flux bins we estimate the counts at several flux density nodes connected with power laws. We observe a generally very steep slope for the counts of about -3.7 at 250 mum, and -4.5 at 350 and 500 mum, over the range approx0.02-0.5 Jy, breaking to a shallower slope below about 0.015 Jy at all three wavelengths. We also describe how to estimate the uncertainties and correlations in this method so that the results can be used for model-fitting. This method should be well suited for analysis of data from the Herschel satellite.

  3. Functional mapping of reaction norms to multiple environmental signals.

    PubMed

    Wu, Jiasheng; Zeng, Yanru; Huang, Jianqing; Hou, Wei; Zhu, Jun; Wu, Rongling

    2007-02-01

    Whether there are different genes involved in response to different environmental signals and how these genes interact to determine the final expression of the trait are of fundamental importance in agricultural and biological research. We present a statistical framework for mapping environment-induced genes (or quantitative trait loci, QTLs) of major effects on the expression of a trait that respond to changing environments. This framework is constructed with a maximum-likelihood-based mixture model, in which the mean and covariance structure of environment-induced responses is modelled. The means for responses to continuous environmental states, referred to as reaction norms, are approximated for different QTL genotypes by mathematical equations that were derived from fundamental biological principles or based on statistical goodness-of-fit to observational data. The residual covariance between different environmental states was modelled by autoregressive processes. Such an approach to studying the genetic control of reaction norms can be expected to be advantageous over traditional mapping approaches in which no biological principles and statistical structures are considered. We demonstrate the analytical procedure and power of this approach by modelling the photosynthetic rate process as a function of temperature and light irradiance. Our approach allows for testing how a QTL affects the reaction norm of photosynthetic rate to a specific environment and whether there exist different QTLs to mediate photosynthetic responses to temperature and light irradiance, respectively. PMID:17517157

  4. A new approach to the statistical treatment of 2D-maps in proteomics using fuzzy logic.

    PubMed

    Marengo, Emilio; Robotti, Elisa; Gianotti, Valentina; Righetti, Pier Giorgio

    2003-01-01

    A new approach to the statistical treatment of 2D-maps has been developed. This method is based on the use of fuzzy logic and allows to take into consideration the typical low reproducibility of 2D-maps. In this approach the signal corresponding to the presence of proteins on the 2D-maps is substituted with probability functions, centred on the signal itself. The standard deviation of the bidimensional gaussian probability function employed to blur the signal allows to assign different uncertainties to the two electrophoretic dimensions. The effect of changing the standard deviation and the digitalisation resolution are investigated. PMID:12650579

  5. The standard map: From Boltzmann-Gibbs statistics to Tsallis statistics.

    PubMed

    Tirnakli, Ugur; Borges, Ernesto P

    2016-01-01

    As well known, Boltzmann-Gibbs statistics is the correct way of thermostatistically approaching ergodic systems. On the other hand, nontrivial ergodicity breakdown and strong correlations typically drag the system into out-of-equilibrium states where Boltzmann-Gibbs statistics fails. For a wide class of such systems, it has been shown in recent years that the correct approach is to use Tsallis statistics instead. Here we show how the dynamics of the paradigmatic conservative (area-preserving) stan-dard map exhibits, in an exceptionally clear manner, the crossing from one statistics to the other. Our results unambiguously illustrate the domains of validity of both Boltzmann-Gibbs and Tsallis statistical distributions. Since various important physical systems from particle confinement in magnetic traps to autoionization of molecular Rydberg states, through particle dynamics in accelerators and comet dynamics, can be reduced to the standard map, our results are expected to enlighten and enable an improved interpretation of diverse experimental and observational results. PMID:27004989

  6. The standard map: From Boltzmann-Gibbs statistics to Tsallis statistics

    PubMed Central

    Tirnakli, Ugur; Borges, Ernesto P.

    2016-01-01

    As well known, Boltzmann-Gibbs statistics is the correct way of thermostatistically approaching ergodic systems. On the other hand, nontrivial ergodicity breakdown and strong correlations typically drag the system into out-of-equilibrium states where Boltzmann-Gibbs statistics fails. For a wide class of such systems, it has been shown in recent years that the correct approach is to use Tsallis statistics instead. Here we show how the dynamics of the paradigmatic conservative (area-preserving) stan-dard map exhibits, in an exceptionally clear manner, the crossing from one statistics to the other. Our results unambiguously illustrate the domains of validity of both Boltzmann-Gibbs and Tsallis statistical distributions. Since various important physical systems from particle confinement in magnetic traps to autoionization of molecular Rydberg states, through particle dynamics in accelerators and comet dynamics, can be reduced to the standard map, our results are expected to enlighten and enable an improved interpretation of diverse experimental and observational results. PMID:27004989

  7. Statistical optimisation techniques in fatigue signal editing problem

    SciTech Connect

    Nopiah, Z. M.; Osman, M. H.; Baharin, N.; Abdullah, S.

    2015-02-03

    Success in fatigue signal editing is determined by the level of length reduction without compromising statistical constraints. A great reduction rate can be achieved by removing small amplitude cycles from the recorded signal. The long recorded signal sometimes renders the cycle-to-cycle editing process daunting. This has encouraged researchers to focus on the segment-based approach. This paper discusses joint application of the Running Damage Extraction (RDE) technique and single constrained Genetic Algorithm (GA) in fatigue signal editing optimisation.. In the first section, the RDE technique is used to restructure and summarise the fatigue strain. This technique combines the overlapping window and fatigue strain-life models. It is designed to identify and isolate the fatigue events that exist in the variable amplitude strain data into different segments whereby the retention of statistical parameters and the vibration energy are considered. In the second section, the fatigue data editing problem is formulated as a constrained single optimisation problem that can be solved using GA method. The GA produces the shortest edited fatigue signal by selecting appropriate segments from a pool of labelling segments. Challenges arise due to constraints on the segment selection by deviation level over three signal properties, namely cumulative fatigue damage, root mean square and kurtosis values. Experimental results over several case studies show that the idea of solving fatigue signal editing within a framework of optimisation is effective and automatic, and that the GA is robust for constrained segment selection.

  8. Structural quantification of cartilage changes using statistical parametric mapping

    NASA Astrophysics Data System (ADS)

    Tamez-Peña, José Gerardo; Barbu-McInnis, Monica; Totterman, Saara

    2007-03-01

    The early detection of Osteoarthritis (OA) treatment efficacy requires monitoring of small changes in cartilage morphology. Current approaches rely in carefully monitoring global cartilage parameters. However, they are not very sensitive to the detection of focal morphological changes in cartilage structure. This work presents the use of the statistical parametric mapping (SPM) for the detection and quantification of changes in cartilage morphology. The SPM is computed by first registering the baseline and the follow-up three dimensional (3D) reconstructions of the cartilage tissue. Once the registration is complete, the thickness changes for every cartilage point is computed which is followed by a model based estimation of the variance of thickness error. The cartilage thickness change and the variance estimations are used to compute the z-score map. The map is used to visualize and quantify significant changes in cartilage thickness. The z-map quantification provides the area of significant changes, the associated volume of changes as well as the average thickness of cartilage loss. Furthermore, thickness change distributions functions are normalized to provide the probability distribution functions (PDF). The PDF can be used to understand and quantify the differences among different treatment groups. The performance of the approach on simulated data and real subject data will be presented.

  9. Statistical-uncertainty-based adaptive filtering of lidar signals

    SciTech Connect

    Fuehrer, P. L.; Friehe, C. A.; Hristov, T. S.; Cooper, D. I.; Eichinger, W. E.

    2000-02-10

    An adaptive filter signal processing technique is developed to overcome the problem of Raman lidar water-vapor mixing ratio (the ratio of the water-vapor density to the dry-air density) with a highly variable statistical uncertainty that increases with decreasing photomultiplier-tube signal strength and masks the true desired water-vapor structure. The technique, applied to horizontal scans, assumes only statistical horizontal homogeneity. The result is a variable spatial resolution water-vapor signal with a constant variance out to a range limit set by a specified signal-to-noise ratio. The technique was applied to Raman water-vapor lidar data obtained at a coastal pier site together with in situ instruments located 320 m from the lidar. The micrometerological humidity data were used to calibrate the ratio of the lidar gains of the H{sub 2}O and the N{sub 2} photomultiplier tubes and set the water-vapor mixing ratio variance for the adaptive filter. For the coastal experiment the effective limit of the lidar range was found to be approximately 200 m for a maximum noise-to-signal variance ratio of 0.1 with the implemented data-reduction procedure. The technique can be adapted to off-horizontal scans with a small reduction in the constraints and is also applicable to other remote-sensing devices that exhibit the same inherent range-dependent signal-to-noise ratio problem. (c) 2000 Optical Society of America.

  10. Statistical-uncertainty-based adaptive filtering of lidar signals.

    PubMed

    Fuehrer, P L; Friehe, C A; Hristov, T S; Cooper, D I; Eichinger, W E

    2000-02-10

    An adaptive filter signal processing technique is developed to overcome the problem of Raman lidar water-vapor mixing ratio (the ratio of the water-vapor density to the dry-air density) with a highly variable statistical uncertainty that increases with decreasing photomultiplier-tube signal strength and masks the true desired water-vapor structure. The technique, applied to horizontal scans, assumes only statistical horizontal homogeneity. The result is a variable spatial resolution water-vapor signal with a constant variance out to a range limit set by a specified signal-to-noise ratio. The technique was applied to Raman water-vapor lidar data obtained at a coastal pier site together with in situ instruments located 320 m from the lidar. The micrometeorological humidity data were used to calibrate the ratio of the lidar gains of the H(2)O and the N(2) photomultiplier tubes and set the water-vapor mixing ratio variance for the adaptive filter. For the coastal experiment the effective limit of the lidar range was found to be approximately 200 m for a maximum noise-to-signal variance ratio of 0.1 with the implemented data-reduction procedure. The technique can be adapted to off-horizontal scans with a small reduction in the constraints and is also applicable to other remote-sensing devices that exhibit the same inherent range-dependent signal-to-noise ratio problem.

  11. One-dimensional statistical parametric mapping in Python.

    PubMed

    Pataky, Todd C

    2012-01-01

    Statistical parametric mapping (SPM) is a topological methodology for detecting field changes in smooth n-dimensional continua. Many classes of biomechanical data are smooth and contained within discrete bounds and as such are well suited to SPM analyses. The current paper accompanies release of 'SPM1D', a free and open-source Python package for conducting SPM analyses on a set of registered 1D curves. Three example applications are presented: (i) kinematics, (ii) ground reaction forces and (iii) contact pressure distribution in probabilistic finite element modelling. In addition to offering a high-level interface to a variety of common statistical tests like t tests, regression and ANOVA, SPM1D also emphasises fundamental concepts of SPM theory through stand-alone example scripts. Source code and documentation are available at: www.tpataky.net/spm1d/.

  12. Statistical limitations in functional neuroimaging. II. Signal detection and statistical inference.

    PubMed Central

    Petersson, K M; Nichols, T E; Poline, J B; Holmes, A P

    1999-01-01

    The field of functional neuroimaging (FNI) methodology has developed into a mature but evolving area of knowledge and its applications have been extensive. A general problem in the analysis of FNI data is finding a signal embedded in noise. This is sometimes called signal detection. Signal detection theory focuses in general on issues relating to the optimization of conditions for separating the signal from noise. When methods from probability theory and mathematical statistics are directly applied in this procedure it is also called statistical inference. In this paper we briefly discuss some aspects of signal detection theory relevant to FNI and, in addition, some common approaches to statistical inference used in FNI. Low-pass filtering in relation to functional-anatomical variability and some effects of filtering on signal detection of interest to FNI are discussed. Also, some general aspects of hypothesis testing and statistical inference are discussed. This includes the need for characterizing the signal in data when the null hypothesis is rejected, the problem of multiple comparisons that is central to FNI data analysis, omnibus tests and some issues related to statistical power in the context of FNI. In turn, random field, scale space, non-parametric and Monte Carlo approaches are reviewed, representing the most common approaches to statistical inference used in FNI. Complementary to these issues an overview and discussion of non-inferential descriptive methods, common statistical models and the problem of model selection is given in a companion paper. In general, model selection is an important prelude to subsequent statistical inference. The emphasis in both papers is on the assumptions and inherent limitations of the methods presented. Most of the methods described here generally serve their purposes well when the inherent assumptions and limitations are taken into account. Significant differences in results between different methods are most apparent in

  13. Signal Processing For Chemical Sensing: Statistics or Biological Inspiration

    NASA Astrophysics Data System (ADS)

    Marco, Santiago

    2011-09-01

    Current analytical instrumentation and continuous sensing can provide huge amounts of data. Automatic signal processing and information evaluation is needed to overcome drowning in data. Today, statistical techniques are typically used to analyse and extract information from continuous signals. However, it is very interesting to note that biology (insects and vertebrates) has found alternative solutions for chemical sensing and information processing. This is a brief introduction to the developments in the European Project: Bio-ICT NEUROCHEM: Biologically Inspired Computation for Chemical Sensing (grant no. 216916) Fp7 project devoted to biomimetic olfactory systems.

  14. Optimum Receiver Structure for PPM Signals with Avalanche Photodiode Statistics

    NASA Technical Reports Server (NTRS)

    Vilnrotter, V.; Srinivasan, M.

    1998-01-01

    The maximum likelihood decision statistic for detection of pulse-position modulated signals with an avalanche photodiode is derived, using the more accurate Webb density rather than Poisson or Gaussian approximations for the distribution of avalanche photodiode output electrons. It is shown that for Webb-distributed output electtrons, the maximum likelihood rule is to choose the PPM word corresponding to the slot with the maximum electron count.

  15. Statistical Signal Analysis for Systems with Interferenced Inputs

    NASA Technical Reports Server (NTRS)

    Bai, R. M.; Mielnicka-Pate, A. L.

    1985-01-01

    A new approach is introduced, based on statistical signal analysis, which overcomes the error due to input signal interference. The model analyzed is given. The input signals u sub 1 (t) and u sub 2 (t) are assumed to be unknown. The measurable signals x sub 1 (t) and x sub 2 (t) are interferened according to the frequency response functions, H sub 12 (f) and H sub 21 (f). The goal of the analysis was to evaluate the power output due to each input, u sub 1 (t) and u sub 2 (t), for the case where both are applied to the same time. In addition, all frequency response functions are calculated. The interferenced system is described by a set of five equations with six unknown functions. An IBM XT Personal Computer, which was interfaced with the FFT, was used to solve the set of equations. The software was tested on an electrical two-input, one-output system. The results were excellent. The research presented includes the analysis of the acoustic radiation from a rectangular plate with two force inputs and the sound pressure as an output signal.

  16. Statistical quality indicators for electron-density maps.

    PubMed

    Tickle, Ian J

    2012-04-01

    The commonly used validation metrics for the local agreement of a structure model with the observed electron density, namely the real-space R (RSR) and the real-space correlation coefficient (RSCC), are reviewed. It is argued that the primary goal of all validation techniques is to verify the accuracy of the model, since precision is an inherent property of the crystal and the data. It is demonstrated that the principal weakness of both of the above metrics is their inability to distinguish the accuracy of the model from its precision. Furthermore, neither of these metrics in their usual implementation indicate the statistical significance of the result. The statistical properties of electron-density maps are reviewed and an improved alternative likelihood-based metric is suggested. This leads naturally to a χ(2) significance test of the difference density using the real-space difference density Z score (RSZD). This is a metric purely of the local model accuracy, as required for effective model validation and structure optimization by practising crystallographers prior to submission of a structure model to the PDB. A new real-space observed density Z score (RSZO) is also proposed; this is a metric purely of the model precision, as a substitute for other precision metrics such as the B factor.

  17. Statistical quality indicators for electron-density maps

    SciTech Connect

    Tickle, Ian J.

    2012-04-01

    A likelihood-based metric for scoring the local agreement of a structure model with the observed electron density is described. The commonly used validation metrics for the local agreement of a structure model with the observed electron density, namely the real-space R (RSR) and the real-space correlation coefficient (RSCC), are reviewed. It is argued that the primary goal of all validation techniques is to verify the accuracy of the model, since precision is an inherent property of the crystal and the data. It is demonstrated that the principal weakness of both of the above metrics is their inability to distinguish the accuracy of the model from its precision. Furthermore, neither of these metrics in their usual implementation indicate the statistical significance of the result. The statistical properties of electron-density maps are reviewed and an improved alternative likelihood-based metric is suggested. This leads naturally to a χ{sup 2} significance test of the difference density using the real-space difference density Z score (RSZD). This is a metric purely of the local model accuracy, as required for effective model validation and structure optimization by practising crystallographers prior to submission of a structure model to the PDB. A new real-space observed density Z score (RSZO) is also proposed; this is a metric purely of the model precision, as a substitute for other precision metrics such as the B factor.

  18. The statistics of local motion signals in naturalistic movies

    PubMed Central

    Nitzany, Eyal I.; Victor, Jonathan D.

    2014-01-01

    Extraction of motion from visual input plays an important role in many visual tasks, such as separation of figure from ground and navigation through space. Several kinds of local motion signals have been distinguished based on mathematical and computational considerations (e.g., motion based on spatiotemporal correlation of luminance, and motion based on spatiotemporal correlation of flicker), but little is known about the prevalence of these different kinds of signals in the real world. To address this question, we first note that different kinds of local motion signals (e.g., Fourier, non-Fourier, and glider) are characterized by second- and higher-order correlations in slanted spatiotemporal regions. The prevalence of local motion signals in natural scenes can thus be estimated by measuring the extent to which each of these correlations are present in space-time patches and whether they are coherent across spatiotemporal scales. We apply this technique to several popular movies. The results show that all three kinds of local motion signals are present in natural movies. While the balance of the different kinds of motion signals varies from segment to segment during the course of each movie, the overall pattern of prevalence of the different kinds of motion and their subtypes, and the correlations between them, is strikingly similar across movies (but is absent from white noise movies). In sum, naturalistic movies contain a diversity of local motion signals that occur with a consistent prevalence and pattern of covariation, indicating a substantial regularity of their high-order spatiotemporal image statistics. PMID:24732243

  19. The statistics of local motion signals in naturalistic movies.

    PubMed

    Nitzany, Eyal I; Victor, Jonathan D

    2014-04-14

    Extraction of motion from visual input plays an important role in many visual tasks, such as separation of figure from ground and navigation through space. Several kinds of local motion signals have been distinguished based on mathematical and computational considerations (e.g., motion based on spatiotemporal correlation of luminance, and motion based on spatiotemporal correlation of flicker), but little is known about the prevalence of these different kinds of signals in the real world. To address this question, we first note that different kinds of local motion signals (e.g., Fourier, non-Fourier, and glider) are characterized by second- and higher-order correlations in slanted spatiotemporal regions. The prevalence of local motion signals in natural scenes can thus be estimated by measuring the extent to which each of these correlations are present in space-time patches and whether they are coherent across spatiotemporal scales. We apply this technique to several popular movies. The results show that all three kinds of local motion signals are present in natural movies. While the balance of the different kinds of motion signals varies from segment to segment during the course of each movie, the overall pattern of prevalence of the different kinds of motion and their subtypes, and the correlations between them, is strikingly similar across movies (but is absent from white noise movies). In sum, naturalistic movies contain a diversity of local motion signals that occur with a consistent prevalence and pattern of covariation, indicating a substantial regularity of their high-order spatiotemporal image statistics.

  20. Statistical Analysis of Noisy Signals Using Classification Tools

    SciTech Connect

    Thompson, Sandra E.; Heredia-Langner, Alejandro; Johnson, Timothy J.; Foster, Nancy S.; Valentine, Nancy B.; Amonette, James E.

    2005-06-04

    The potential use of chemicals, biotoxins and biological pathogens are a threat to military and police forces as well as the general public. Rapid identification of these agents is made difficult due to the noisy nature of the signal that can be obtained from portable, in-field sensors. In previously published articles, we created a flowchart that illustrated a method for triaging bacterial identification by combining standard statistical techniques for discrimination and identification with mid-infrared spectroscopic data. The present work documents the process of characterizing and eliminating the sources of the noise and outlines how multidisciplinary teams are necessary to accomplish that goal.

  1. Linear System Models for Ultrasonic Imaging: Application to Signal Statistics

    PubMed Central

    Zemp, Roger J.; Abbey, Craig K.; Insana, Michael F.

    2009-01-01

    Linear equations for modeling echo signals from shift-variant systems forming ultrasonic B-mode, Doppler, and strain images are analyzed and extended. The approach is based on a solution to the homogeneous wave equation for random inhomogeneous media. When the system is shift-variant, the spatial sensitivity function—defined as a spatial weighting function that determines the scattering volume for a fixed point of time—has advantages over the point-spread function traditionally used to analyze ultrasound systems. Spatial sensitivity functions are necessary for determining statistical moments in the context of rigorous image quality assessment, and they are time-reversed copies of point-spread functions for shift variant systems. A criterion is proposed to assess the validity of a local shift-invariance assumption. The analysis reveals realistic situations in which in-phase signals are correlated to the corresponding quadrature signals, which has strong implications for assessing lesion detectability. Also revealed is an opportunity to enhance near- and far-field spatial resolution by matched filtering unfocused beams. The analysis connects several well-known approaches to modeling ultrasonic echo signals. PMID:12839176

  2. Statistical techniques for signal generation: the Australian experience.

    PubMed

    Purcell, Patrick; Barty, Simon

    2002-01-01

    National voluntary reporting systems generate large volumes of clinical data pertinent to drug safety. Currently descriptive statistical techniques are used to assist in the detection of drug safety 'signals'. Australian data have been coded according to guidelines formulated almost 30 years ago and which have resulted in many drugs which are not associated with an adverse drug reaction or 'innocent bystander' drugs being recorded as 'suspected' in individual reports. In this paper we explore the application of an iterative probability filtering algorithm titled 'PROFILE'. This serves to identify the 'signals' and remove the 'innocent bystander' drugs, thus providing a clearer view of the drugs most likely to have caused the reactions. Reaction terms analysed include neutropenia, agranulocytosis, hypotension, hypertension, myocardial infarction, neuroleptic malignant syndrome, and rectal haemorrhage. In this version of PROFILE, Fishers exact test has been used as the statistical tool but other methods could be used in future. Advantages and limitations of the method and its assumptions are discussed together with the rationale underlying the method and suggestions for further enhancements.

  3. Signal processing for imaging and mapping ladar

    NASA Astrophysics Data System (ADS)

    Grönwall, Christina; Tolt, Gustav

    2011-11-01

    The new generation laser-based FLASH 3D imaging sensors enable data collection at video rate. This opens up for realtime data analysis but also set demands on the signal processing. In this paper the possibilities and challenges with this new data type are discussed. The commonly used focal plane array based detectors produce range estimates that vary with the target's surface reflectance and target range, and our experience is that the built-in signal processing may not compensate fully for that. We propose a simple adjustment that can be used even if some sensor parameters are not known. The cost for the instantaneous image collection is, compared to scanning laser radar systems, lower range accuracy. By gathering range information from several frames the geometrical information of the target can be obtained. We also present an approach of how range data can be used to remove foreground clutter in front of a target. Further, we illustrate how range data enables target classification in near real-time and that the results can be improved if several frames are co-registered. Examples using data from forest and maritime scenes are shown.

  4. A statistical procedure for fire risk mapping in Italy

    NASA Astrophysics Data System (ADS)

    Fiorucci, Paolo; Biondi, Guido; Campo, Lorenzo; D'Andrea, Mirko

    2015-04-01

    The high topographic and vegetation heterogeneity makes Italy vulnerable to forest fires both in the summer and in winter. In particular, northern regions are predominantly characterized by a winter fire regime, mainly due to frequent extremely dry winds from the north, while southern and central regions and the large islands are characterized by a severe summer fire regime, because of the higher temperatures and prolonged lack of precipitation. The threat of wildfires in Italy is not confined to wooded areas as they extend to agricultural areas and urban-forest interface areas. In view of the limited availability of fire risk management resources, most of which are used in the management of national and regional air services, it is necessary to precisely identify the areas most vulnerable to fire risk. The few resources available can thus be used on a yearly basis to mitigate problems in the areas at highest risk by defining a program of forest management interventions, which is expected to make a significant contribution to the problem in a few years' time. Given the availability of fire perimeters mapped over a period spanning from 5 to 10 years, depending by the region, a statistical procedure was defined in order to assess areas at risk based on objective criteria by observing past fire events. The availability of fire perimeters combined with a detailed knowledge of topography and land cover allowed to understand which are the main features involved in forest fire occurrences and their behavior. The seasonality of the fire regime was also considered, partitioning the analysis in two macro season (November-April and May- October). In addition, the total precipitation obtained from the interpolation of 30 years-long time series from 460 raingauges and the average air temperature obtained downscaling 30 years ERA-INTERIM data series were considered. The analysis consists on the subdivision of the territory in classes based on the named information layers

  5. Statistical isotropy violation in WMAP CMB maps resulting from non-circular beams

    NASA Astrophysics Data System (ADS)

    Das, Santanu; Mitra, Sanjit; Rotti, Aditya; Pant, Nidhi; Souradeep, Tarun

    2016-06-01

    Statistical isotropy (SI) of cosmic microwave background (CMB) fluctuations is a key observational test to validate the cosmological principle underlying the standard model of cosmology. While a detection of SI violation would have immense cosmological ramification, it is important to recognise their possible origin in systematic effects of observations. The WMAP seven year (WMAP-7) release claimed significant deviation from SI in the bipolar spherical harmonic (BipoSH) coefficients and . Here we present the first explicit reproduction of the measurements reported in WMAP-7, confirming that beam systematics alone can completely account for the measured SI violation. The possibility of such a systematic origin was alluded to in WMAP-7 paper itself and other authors but not as explicitly so as to account for it accurately. We simulate CMB maps using the actual WMAP non-circular beams and scanning strategy. Our estimated BipoSH spectra from these maps match the WMAP-7 results very well. It is also evident that only a very careful and adequately detailed modelling, as carried out here, can conclusively establish that the entire signal arises from non-circular beam effect. This is important since cosmic SI violation signals are expected to be subtle and dismissing a large SI violation signal as observational artefact based on simplistic plausibility arguments run the serious risk of "throwing the baby out with the bathwater".

  6. Evaluation of current statistical approaches for predictive geomorphological mapping

    NASA Astrophysics Data System (ADS)

    Miska, Luoto; Jan, Hjort

    2005-04-01

    Predictive models are increasingly used in geomorphology, but systematic evaluations of novel statistical techniques are still limited. The aim of this study was to compare the accuracy of generalized linear models (GLM), generalized additive models (GAM), classification tree analysis (CTA), neural networks (ANN) and multiple adaptive regression splines (MARS) in predictive geomorphological modelling. Five different distribution models both for non-sorted and sorted patterned ground were constructed on the basis of four terrain parameters and four soil variables. To evaluate the models, the original data set of 9997 squares of 1 ha in size was randomly divided into model training (70%, n=6998) and model evaluation sets (30%, n=2999). In general, active sorted patterned ground is clearly defined in upper fell areas with high slope angle and till soils. Active non-sorted patterned ground is more common in valleys with higher soil moisture and fine-scale concave topography. The predictive performance of each model was evaluated using the area under the receiver operating characteristic curve (AUC) and the Kappa value. The relatively high discrimination capacity of all models, AUC=0.85 0.88 and Kappa=0.49 0.56, implies that the model's predictions provide an acceptable index of sorted and non-sorted patterned ground occurrence. The best performance for model calibration data for both data sets was achieved by the CTA. However, when the predictive mapping ability was explored through the evaluation data set, the model accuracies of CTA decreased clearly compared to the other modelling techniques. For model evaluation data MARS performed marginally best. Our results show that the digital elevation model and soil data can be used to predict relatively robustly the activity of patterned ground in fine scale in a subarctic landscape. This indicates that predictive geomorphological modelling has the advantage of providing relevant and useful information on earth surface

  7. Map4k4 suppresses Srebp-1 and adipocyte lipogenesis independent of JNK signaling[S

    PubMed Central

    Danai, Laura V.; Guilherme, Adilson; Guntur, Kalyani V.; Straubhaar, Juerg; Nicoloro, Sarah M.; Czech, Michael P.

    2013-01-01

    Adipose tissue lipogenesis is paradoxically impaired in human obesity, promoting ectopic triglyceride (TG) deposition, lipotoxicity, and insulin resistance. We previously identified mitogen-activated protein kinase kinase kinase kinase 4 (Map4k4), a sterile 20 protein kinase reported to be upstream of c-Jun NH2-terminal kinase (JNK) signaling, as a novel negative regulator of insulin-stimulated glucose transport in adipocytes. Using full-genome microarray analysis we uncovered a novel role for Map4k4 as a suppressor of lipid synthesis. We further report here the surprising finding that Map4k4 suppresses adipocyte lipogenesis independently of JNK. Thus, while Map4k4 silencing in adipocytes enhances the expression of lipogenic enzymes, concomitant with increased conversion of 14C-glucose and 14C-acetate into TGs and fatty acids, JNK1 and JNK2 depletion causes the opposite effects. Furthermore, high expression of Map4k4 fails to activate endogenous JNK, while Map4k4 depletion does not attenuate JNK activation by tumor necrosis factor α. Map4k4 silencing in cultured adipocytes elevates both the total protein expression and cleavage of sterol-regulated element binding protein-1 (Srebp-1) in a rapamycin-sensitive manner, consistent with Map4k4 signaling via mechanistic target of rapamycin complex 1 (mTORC1). We show Map4k4 depletion requires Srebp-1 upregulation to increase lipogenesis and further show that Map4k4 promotes AMP-protein kinase (AMPK) signaling and the phosphorylation of mTORC1 binding partner raptor (Ser792) to inhibit mTORC1. Our results indicate that Map4k4 inhibits adipose lipogenesis by suppression of Srebp-1 in an AMPK- and mTOR-dependent but JNK-independent mechanism. PMID:23924694

  8. The statistical mechanics of complex signaling networks: nerve growth factor signaling

    NASA Astrophysics Data System (ADS)

    Brown, K. S.; Hill, C. C.; Calero, G. A.; Myers, C. R.; Lee, K. H.; Sethna, J. P.; Cerione, R. A.

    2004-10-01

    The inherent complexity of cellular signaling networks and their importance to a wide range of cellular functions necessitates the development of modeling methods that can be applied toward making predictions and highlighting the appropriate experiments to test our understanding of how these systems are designed and function. We use methods of statistical mechanics to extract useful predictions for complex cellular signaling networks. A key difficulty with signaling models is that, while significant effort is being made to experimentally measure the rate constants for individual steps in these networks, many of the parameters required to describe their behavior remain unknown or at best represent estimates. To establish the usefulness of our approach, we have applied our methods toward modeling the nerve growth factor (NGF)-induced differentiation of neuronal cells. In particular, we study the actions of NGF and mitogenic epidermal growth factor (EGF) in rat pheochromocytoma (PC12) cells. Through a network of intermediate signaling proteins, each of these growth factors stimulates extracellular regulated kinase (Erk) phosphorylation with distinct dynamical profiles. Using our modeling approach, we are able to predict the influence of specific signaling modules in determining the integrated cellular response to the two growth factors. Our methods also raise some interesting insights into the design and possible evolution of cellular systems, highlighting an inherent property of these systems that we call 'sloppiness.'

  9. Statistical diagnostics to identify galactic foregrounds in B-mode maps.

    PubMed

    Kamionkowski, Marc; Kovetz, Ely D

    2014-11-01

    Recent developments in the search for inflationary gravitational waves in the cosmic microwave background polarization motivate the search for new diagnostics to distinguish the Galactic foreground contribution to B modes from the cosmic signal. We show that B modes from these foregrounds should exhibit a local hexadecapolar departure in power from statistical isotropy (SI). We present a simple algorithm to search for a uniform SI violation of this sort, as may arise in a sufficiently small patch of sky. We then show how to search for these effects if the orientation of the SI violation varies across the survey region, as is more likely to occur in surveys with more sky coverage. If detected, these departures from Gaussianity would indicate some level of Galactic foreground contamination in the B-mode maps. Given uncertainties about foreground properties, though, caution should be exercised in attributing a null detection to an absence of foregrounds. PMID:25415897

  10. LOCALIZING NATIONAL FRAGMENTATION STATISTICS WITH FOREST TYPE MAPS

    EPA Science Inventory

    Fragmmentation of forest types is an indicator of biodiversity in the Montreal Process, but the available national data permit assessment of only overall forestland fragmentation, not forest type fragmentation. Here we illustrate how to localize national statistics from the 2003...

  11. A robust vector field correction method via a mixture statistical model of PIV signal

    NASA Astrophysics Data System (ADS)

    Lee, Yong; Yang, Hua; Yin, Zhouping

    2016-03-01

    Outlier (spurious vector) is a common problem in practical velocity field measurement using particle image velocimetry technology (PIV), and it should be validated and replaced by a reliable value. One of the most challenging problems is to correctly label the outliers under the circumstance that measurement noise exists or the flow becomes turbulent. Moreover, the outlier's cluster occurrence makes it difficult to pick out all the outliers. Most of current methods validate and correct the outliers using local statistical models in a single pass. In this work, a vector field correction (VFC) method is proposed directly from a mixture statistical model of PIV signal. Actually, this problem is formulated as a maximum a posteriori (MAP) estimation of a Bayesian model with hidden/latent variables, labeling the outliers in the original field. The solution of this MAP estimation, i.e., the outlier set and the restored flow field, is optimized iteratively using an expectation-maximization algorithm. We illustrated this VFC method on two kinds of synthetic velocity fields and two kinds of experimental data and demonstrated that it is robust to a very large number of outliers (even up to 60 %). Besides, the proposed VFC method has high accuracy and excellent compatibility for clustered outliers, compared with the state-of-the-art methods. Our VFC algorithm is computationally efficient, and corresponding Matlab code is provided for others to use it. In addition, our approach is general and can be seamlessly extended to three-dimensional-three-component (3D3C) PIV data.

  12. Planck 2013 results. XXI. Power spectrum and high-order statistics of the Planck all-sky Compton parameter map

    NASA Astrophysics Data System (ADS)

    Planck Collaboration; Ade, P. A. R.; Aghanim, N.; Armitage-Caplan, C.; Arnaud, M.; Ashdown, M.; Atrio-Barandela, F.; Aumont, J.; Baccigalupi, C.; Banday, A. J.; Barreiro, R. B.; Bartlett, J. G.; Battaner, E.; Benabed, K.; Benoît, A.; Benoit-Lévy, A.; Bernard, J.-P.; Bersanelli, M.; Bielewicz, P.; Bobin, J.; Bock, J. J.; Bonaldi, A.; Bond, J. R.; Borrill, J.; Bouchet, F. R.; Bridges, M.; Bucher, M.; Burigana, C.; Butler, R. C.; Cardoso, J.-F.; Carvalho, P.; Catalano, A.; Challinor, A.; Chamballu, A.; Chiang, H. C.; Chiang, L.-Y.; Christensen, P. R.; Church, S.; Clements, D. L.; Colombi, S.; Colombo, L. P. L.; Comis, B.; Couchot, F.; Coulais, A.; Crill, B. P.; Curto, A.; Cuttaia, F.; Da Silva, A.; Danese, L.; Davies, R. D.; Davis, R. J.; de Bernardis, P.; de Rosa, A.; de Zotti, G.; Delabrouille, J.; Delouis, J.-M.; Désert, F.-X.; Dickinson, C.; Diego, J. M.; Dolag, K.; Dole, H.; Donzelli, S.; Doré, O.; Douspis, M.; Dupac, X.; Efstathiou, G.; Enßlin, T. A.; Eriksen, H. K.; Finelli, F.; Flores-Cacho, I.; Forni, O.; Frailis, M.; Franceschi, E.; Galeotta, S.; Ganga, K.; Génova-Santos, R. T.; Giard, M.; Giardino, G.; Giraud-Héraud, Y.; González-Nuevo, J.; Górski, K. M.; Gratton, S.; Gregorio, A.; Gruppuso, A.; Hansen, F. K.; Hanson, D.; Harrison, D.; Henrot-Versillé, S.; Hernández-Monteagudo, C.; Herranz, D.; Hildebrandt, S. R.; Hivon, E.; Hobson, M.; Holmes, W. A.; Hornstrup, A.; Hovest, W.; Huffenberger, K. M.; Hurier, G.; Jaffe, A. H.; Jaffe, T. R.; Jones, W. C.; Juvela, M.; Keihänen, E.; Keskitalo, R.; Kisner, T. S.; Kneissl, R.; Knoche, J.; Knox, L.; Kunz, M.; Kurki-Suonio, H.; Lacasa, F.; Lagache, G.; Lähteenmäki, A.; Lamarre, J.-M.; Lasenby, A.; Laureijs, R. J.; Lawrence, C. R.; Leahy, J. P.; Leonardi, R.; León-Tavares, J.; Lesgourgues, J.; Liguori, M.; Lilje, P. B.; Linden-Vørnle, M.; López-Caniego, M.; Lubin, P. M.; Macías-Pérez, J. F.; Maffei, B.; Maino, D.; Mandolesi, N.; Marcos-Caballero, A.; Maris, M.; Marshall, D. J.; Martin, P. G.; Martínez-González, E.; Masi, S.; Massardi, M.; Matarrese, S.; Matthai, F.; Mazzotta, P.; Melchiorri, A.; Melin, J.-B.; Mendes, L.; Mennella, A.; Migliaccio, M.; Mitra, S.; Miville-Deschênes, M.-A.; Moneti, A.; Montier, L.; Morgante, G.; Mortlock, D.; Moss, A.; Munshi, D.; Naselsky, P.; Nati, F.; Natoli, P.; Netterfield, C. B.; Nørgaard-Nielsen, H. U.; Noviello, F.; Novikov, D.; Novikov, I.; Osborne, S.; Oxborrow, C. A.; Paci, F.; Pagano, L.; Pajot, F.; Paoletti, D.; Partridge, B.; Pasian, F.; Patanchon, G.; Perdereau, O.; Perotto, L.; Perrotta, F.; Piacentini, F.; Piat, M.; Pierpaoli, E.; Pietrobon, D.; Plaszczynski, S.; Pointecouteau, E.; Polenta, G.; Ponthieu, N.; Popa, L.; Poutanen, T.; Pratt, G. W.; Prézeau, G.; Prunet, S.; Puget, J.-L.; Rachen, J. P.; Rebolo, R.; Reinecke, M.; Remazeilles, M.; Renault, C.; Ricciardi, S.; Riller, T.; Ristorcelli, I.; Rocha, G.; Rosset, C.; Rossetti, M.; Roudier, G.; Rubiño-Martín, J. A.; Rusholme, B.; Sandri, M.; Santos, D.; Savini, G.; Scott, D.; Seiffert, M. D.; Shellard, E. P. S.; Spencer, L. D.; Starck, J.-L.; Stolyarov, V.; Stompor, R.; Sudiwala, R.; Sunyaev, R.; Sureau, F.; Sutton, D.; Suur-Uski, A.-S.; Sygnet, J.-F.; Tauber, J. A.; Tavagnacco, D.; Terenzi, L.; Toffolatti, L.; Tomasi, M.; Tristram, M.; Tucci, M.; Tuovinen, J.; Umana, G.; Valenziano, L.; Valiviita, J.; Van Tent, B.; Varis, J.; Vielva, P.; Villa, F.; Vittorio, N.; Wade, L. A.; Wandelt, B. D.; White, S. D. M.; Yvon, D.; Zacchei, A.; Zonca, A.

    2014-11-01

    We have constructed the first all-sky map of the thermal Sunyaev-Zeldovich (tSZ) effect by applying specifically tailored component separation algorithms to the 100 to 857 GHz frequency channel maps from the Planck survey. This map shows an obvious galaxy cluster tSZ signal that is well matched with blindly detected clusters in the Planck SZ catalogue. To characterize the signal in the tSZ map we have computed its angular power spectrum. At large angular scales (ℓ < 60), the major foreground contaminant is the diffuse thermal dust emission. At small angular scales (ℓ > 500) the clustered cosmic infrared background and residual point sources are the major contaminants. These foregrounds are carefully modelled and subtracted. We thus measure the tSZ power spectrum over angular scales 0.17° ≲ θ ≲ 3.0° that were previously unexplored. The measured tSZ power spectrum is consistent with that expected from the Planck catalogue of SZ sources, with clear evidence of additional signal from unresolved clusters and, potentially, diffuse warm baryons. Marginalized band-powers of the Planck tSZ power spectrum and the best-fit model are given. The non-Gaussianity of the Compton parameter map is further characterized by computing its 1D probability distribution function and its bispectrum. The measured tSZ power spectrum and high order statistics are used to place constraints on σ8.

  13. A statistical approach for validating eSOTER and digital soil maps in front of traditional soil maps

    NASA Astrophysics Data System (ADS)

    Bock, Michael; Baritz, Rainer; Köthe, Rüdiger; Melms, Stephan; Günther, Susann

    2015-04-01

    During the European research project eSOTER, three different Digital Soil Maps (DSM) were developed for the pilot area Chemnitz 1:250,000 (FP7 eSOTER project, grant agreement nr. 211578). The core task of the project was to revise the SOTER method for the interpretation of soil and terrain data. It was one of the working hypothesis that eSOTER does not only provide terrain data with typical soil profiles, but that the new products actually perform like a conceptual soil map. The three eSOTER maps for the pilot area considerably differed in spatial representation and content of soil classes. In this study we compare the three eSOTER maps against existing reconnaissance soil maps keeping in mind that traditional soil maps have many subjective issues and intended bias regarding the overestimation and emphasize of certain features. Hence, a true validation of the proper representation of modeled soil maps is hardly possible; rather a statistical comparison between modeled and empirical approaches is possible. If eSOTER data represent conceptual soil maps, then different eSOTER, DSM and conventional maps from various sources and different regions could be harmonized towards consistent new data sets for large areas including the whole European continent. One of the eSOTER maps has been developed closely to the traditional SOTER method: terrain classification data (derived from SRTM DEM) were combined with lithology data (re-interpreted geological map); the corresponding terrain units were then extended with soil information: a very dense regional soil profile data set was used to define soil mapping units based on a statistical grouping of terrain units. The second map is a pure DSM map using continuous terrain parameters instead of terrain classification; radiospectrometric data were used to supplement parent material information from geology maps. The classification method Random Forest was used. The third approach predicts soil diagnostic properties based on

  14. Signaling Network Map of Endothelial TEK Tyrosine Kinase.

    PubMed

    Khan, Aafaque Ahmad; Sandhya, Varot K; Singh, Priyata; Parthasarathy, Deepak; Kumar, Awinav; Advani, Jayshree; Gattu, Rudrappa; Ranjit, Dhanya V; Vaidyanathan, Rama; Mathur, Premendu Prakash; Prasad, T S Keshava; Mac Gabhann, F; Pandey, Akhilesh; Raju, Rajesh; Gowda, Harsha

    2014-01-01

    TEK tyrosine kinase is primarily expressed on endothelial cells and is most commonly referred to as TIE2. TIE2 is a receptor tyrosine kinase modulated by its ligands, angiopoietins, to regulate the development and remodeling of vascular system. It is also one of the critical pathways associated with tumor angiogenesis and familial venous malformations. Apart from the vascular system, TIE2 signaling is also associated with postnatal hematopoiesis. Despite the involvement of TIE2-angiopoietin system in several diseases, the downstream molecular events of TIE2-angiopoietin signaling are not reported in any pathway repository. Therefore, carrying out a detailed review of published literature, we have documented molecular signaling events mediated by TIE2 in response to angiopoietins and developed a network map of TIE2 signaling. The pathway information is freely available to the scientific community through NetPath, a manually curated resource of signaling pathways. We hope that this pathway resource will provide an in-depth view of TIE2-angiopoietin signaling and will lead to identification of potential therapeutic targets for TIE2-angiopoietin associated disorders.

  15. Interfacing US Census map files with statistical graphics software: Application and use in epidemiology

    SciTech Connect

    Rizzardi, M.; Mohr, M.S.; Merrill, D.W.; Selvin, S. California Univ., Berkeley, CA . School of Public Health)

    1993-03-01

    In 1990, the United States Bureau of the Census released detailed geographic map files known as TIGER/Line (Topologically Integrated Geographic Encoding and Referencing). The TIGER files, accessible through purchase or Federal repository libraries, contain 24 billion characters of data describing various geographic features including coastlines, hydrography, transportation networks, political boundaries, etc. covering the entire United States. Many of these physical features are of potential interest in epidemiological case studies. Unfortunately, the TIGER database only provides raw alphanumeric data; no utility software, graphical or otherwise, is included. Recently, the S statistical software package has been extended to include a map display function. The map function augments S's high-level approach toward statistical analysis and graphical display of data. Coupling this statistical software with the map database developed for US Census data collection will facilitate epidemiological research. We discuss the technical background necessary to utilize the TIGER database for mapping with S. Two types of S maps, segment-based and polygon-based, are discussed along with methods to construct them from TIGER data. Polygon-based maps are useful for displaying regional statistical data; e.g., disease rates or incidence at the census tract level. Segment-based maps are easier to assemble and appropriate if the data are not regionalized. Census tract data of AIDS incidence in San Francisco (CA) and lung cancer case locations relative to petrochemical refinery sites in Contra Costa County (CA) are used to illustrate the methods and potential uses of interfacing the TIGER database with S.

  16. Effects of Concept Mapping Strategy on Learning Performance in Business and Economics Statistics

    ERIC Educational Resources Information Center

    Chiou, Chei-Chang

    2009-01-01

    A concept map (CM) is a hierarchically arranged, graphic representation of the relationships among concepts. Concept mapping (CMING) is the process of constructing a CM. This paper examines whether a CMING strategy can be useful in helping students to improve their learning performance in a business and economics statistics course. A single…

  17. Visual Map Development: Bidirectional Signaling, Bifunctional Guidance Molecules, and Competition

    PubMed Central

    Feldheim, David A.; O’Leary, Dennis D. M.

    2010-01-01

    Topographic maps are a two-dimensional representation of one neural structure within another and serve as the main strategy to organize sensory information. The retina’s projection via axons of retinal ganglion cells to midbrain visual centers, the optic tectum/superior colliculus, is the leading model to elucidate mechanisms of topographic map formation. Each axis of the retina is mapped independently using different mechanisms and sets of axon guidance molecules expressed in gradients to achieve the goal of representing a point in the retina onto a point within the target. An axon’s termination along the temporal-nasal mapping axis is determined by opposing gradients of EphAs and ephrin-As that act through their forward and reverse signaling, respectively, within the projecting axons, each of which inhibits interstitial branching, cooperating with a branch-promoting activity, to generate topographic specific branching along the shaft of the parent axons that overshoot their correct termination zone along the anterior-posterior axis of the target. The dorsal-ventral termination position is then determined using a gradient of ephrin-B that can act as a repellent or attractant depending on the ephrin-B concentration relative to EphB levels on the interstitial branches to guide them along the medial-lateral axis of the target to their correct termination zone, where they arborize. In both cases, axon-axon competition results in axon mapping based on relative rather than absolute levels of repellent or attractant activity. The map is subsequently refined through large-scale pruning driven in large part by patterned retinal activity. PMID:20880989

  18. Assessing the relative effectiveness of statistical downscaling and distribution mapping in reproducing rainfall statistics based on climate model results

    NASA Astrophysics Data System (ADS)

    Langousis, Andreas; Mamalakis, Antonios; Deidda, Roberto; Marrocu, Marino

    2016-01-01

    To improve the level skill of climate models (CMs) in reproducing the statistics of daily rainfall at a basin level, two types of statistical approaches have been suggested. One is statistical correction of CM rainfall outputs based on historical series of precipitation. The other, usually referred to as statistical rainfall downscaling, is the use of stochastic models to conditionally simulate rainfall series, based on large-scale atmospheric forcing from CMs. While promising, the latter approach attracted reduced attention in recent years, since the developed downscaling schemes involved complex weather identification procedures, while demonstrating limited success in reproducing several statistical features of rainfall. In a recent effort, Langousis and Kaleris () developed a statistical framework for simulation of daily rainfall intensities conditional on upper-air variables, which is simpler to implement and more accurately reproduces several statistical properties of actual rainfall records. Here we study the relative performance of: (a) direct statistical correction of CM rainfall outputs using nonparametric distribution mapping, and (b) the statistical downscaling scheme of Langousis and Kaleris (), in reproducing the historical rainfall statistics, including rainfall extremes, at a regional level. This is done for an intermediate-sized catchment in Italy, i.e., the Flumendosa catchment, using rainfall and atmospheric data from four CMs of the ENSEMBLES project. The obtained results are promising, since the proposed downscaling scheme is more accurate and robust in reproducing a number of historical rainfall statistics, independent of the CM used and the characteristics of the calibration period. This is particularly the case for yearly rainfall maxima.

  19. A network map of Interleukin-10 signaling pathway.

    PubMed

    Verma, Renu; Balakrishnan, Lavanya; Sharma, Kusum; Khan, Aafaque Ahmad; Advani, Jayshree; Gowda, Harsha; Tripathy, Srikanth Prasad; Suar, Mrutyunjay; Pandey, Akhilesh; Gandotra, Sheetal; Prasad, T S Keshava; Shankar, Subramanian

    2016-03-01

    Interleukin-10 (IL-10) is an anti-inflammatory cytokine with important immunoregulatory functions. It is primarily secreted by antigen-presenting cells such as activated T-cells, monocytes, B-cells and macrophages. In biologically functional form, it exists as a homodimer that binds to tetrameric heterodimer IL-10 receptor and induces downstream signaling. IL-10 is associated with survival, proliferation and anti-apoptotic activities of various cancers such as Burkitt lymphoma, non-Hodgkins lymphoma and non-small scell lung cancer. In addition, it plays a central role in survival and persistence of intracellular pathogens such as Leishmania donovani, Mycobacterium tuberculosis and Trypanosoma cruzi inside the host. The signaling mechanisms of IL-10 cytokine are not well explored and a well annotated pathway map has been lacking. To this end, we developed a pathway resource by manually annotating the IL-10 induced signaling molecules derived from literature. The reactions were categorized under molecular associations, activation/inhibition, catalysis, transport and gene regulation. In all, 37 molecules and 76 reactions were annotated. The IL-10 signaling pathway can be freely accessed through NetPath, a resource of signal transduction pathways previously developed by our group. PMID:26253919

  20. Develop Advanced Nonlinear Signal Analysis Topographical Mapping System

    NASA Technical Reports Server (NTRS)

    Jong, Jen-Yi

    1997-01-01

    During the development of the SSME, a hierarchy of advanced signal analysis techniques for mechanical signature analysis has been developed by NASA and AI Signal Research Inc. (ASRI) to improve the safety and reliability for Space Shuttle operations. These techniques can process and identify intelligent information hidden in a measured signal which is often unidentifiable using conventional signal analysis methods. Currently, due to the highly interactive processing requirements and the volume of dynamic data involved, detailed diagnostic analysis is being performed manually which requires immense man-hours with extensive human interface. To overcome this manual process, NASA implemented this program to develop an Advanced nonlinear signal Analysis Topographical Mapping System (ATMS) to provide automatic/unsupervised engine diagnostic capabilities. The ATMS will utilize a rule-based Clips expert system to supervise a hierarchy of diagnostic signature analysis techniques in the Advanced Signal Analysis Library (ASAL). ASAL will perform automatic signal processing, archiving, and anomaly detection/identification tasks in order to provide an intelligent and fully automated engine diagnostic capability. The ATMS has been successfully developed under this contract. In summary, the program objectives to design, develop, test and conduct performance evaluation for an automated engine diagnostic system have been successfully achieved. Software implementation of the entire ATMS system on MSFC's OISPS computer has been completed. The significance of the ATMS developed under this program is attributed to the fully automated coherence analysis capability for anomaly detection and identification which can greatly enhance the power and reliability of engine diagnostic evaluation. The results have demonstrated that ATMS can significantly save time and man-hours in performing engine test/flight data analysis and performance evaluation of large volumes of dynamic test data.

  1. Construction of cosmic string induced temperature anisotropy maps with CMBFAST and statistical analysis

    NASA Astrophysics Data System (ADS)

    Simatos, N.; Perivolaropoulos, L.

    2001-01-01

    We use the publicly available code CMBFAST, as modified by Pogosian and Vachaspati, to simulate the effects of wiggly cosmic strings on the cosmic microwave background (CMB). Using the modified CMBFAST code, which takes into account vector modes and models wiggly cosmic strings by the one-scale model, we go beyond the angular power spectrum to construct CMB temperature maps with a resolution of a few degrees. The statistics of these maps are then studied using conventional and recently proposed statistical tests optimized for the detection of hidden temperature discontinuities induced by the Gott-Kaiser-Stebbins effect. We show, however, that these realistic maps cannot be distinguished in a statistically significant way from purely Gaussian maps with an identical power spectrum.

  2. Three-Dimensional Statistical Gas Distribution Mapping in an Uncontrolled Indoor Environment

    SciTech Connect

    Reggente, Matteo; Lilienthal, Achim J.

    2009-05-23

    In this paper we present a statistical method to build three-dimensional gas distribution maps (3D-DM). The proposed mapping technique uses kernel extrapolation with a tri-variate Gaussian kernel that models the likelihood that a reading represents the concentration distribution at a distant location in the three dimensions. The method is evaluated using a mobile robot equipped with three 'e-noses' mounted at different heights. Initial experiments in an uncontrolled indoor environment are presented and evaluated with respect to the ability of the 3D map, computed from the lower and upper nose, to predict the map from the middle nose.

  3. Statistical and signal-processing concepts in surface metrology

    SciTech Connect

    Church, E.L.; Takacs, P.Z.

    1986-03-01

    This paper proposes the use of a simple two-scale model of surface roughness for testing and specifying the topographic figure and finish of synchrotron-radiation mirrors. In this approach the effects of figure and finish are described in terms of their slope distribution and power spectrum, respectively, which are then combined with the system point spread function to produce a composite image. The result can be used to predict mirror performance or to translate design requirements into manufacturing specifications. Pacing problems in this approach are the development of a practical long-trace slope-profiling instrument and realistic statistical models for figure and finish errors.

  4. Statistical measures of Planck scale signal correlations in interferometers

    SciTech Connect

    Hogan, Craig J.; Kwon, Ohkyung

    2015-06-22

    A model-independent statistical framework is presented to interpret data from systems where the mean time derivative of positional cross correlation between world lines, a measure of spreading in a quantum geometrical wave function, is measured with a precision smaller than the Planck time. The framework provides a general way to constrain possible departures from perfect independence of classical world lines, associated with Planck scale bounds on positional information. A parametrized candidate set of possible correlation functions is shown to be consistent with the known causal structure of the classical geometry measured by an apparatus, and the holographic scaling of information suggested by gravity. Frequency-domain power spectra are derived that can be compared with interferometer data. As a result, simple projections of sensitivity for specific experimental set-ups suggests that measurements will directly yield constraints on a universal time derivative of the correlation function, and thereby confirm or rule out a class of Planck scale departures from classical geometry.

  5. Interfacing US Census map files with statistical graphics software: Application and use in epidemiology. Revision 1

    SciTech Connect

    Rizzardi, M.; Mohr, M.S.; Merrill, D.W.; Selvin, S. |

    1993-03-01

    In 1990, the United States Bureau of the Census released detailed geographic map files known as TIGER/Line (Topologically Integrated Geographic Encoding and Referencing). The TIGER files, accessible through purchase or Federal repository libraries, contain 24 billion characters of data describing various geographic features including coastlines, hydrography, transportation networks, political boundaries, etc. covering the entire United States. Many of these physical features are of potential interest in epidemiological case studies. Unfortunately, the TIGER database only provides raw alphanumeric data; no utility software, graphical or otherwise, is included. Recently, the S statistical software package has been extended to include a map display function. The map function augments S`s high-level approach toward statistical analysis and graphical display of data. Coupling this statistical software with the map database developed for US Census data collection will facilitate epidemiological research. We discuss the technical background necessary to utilize the TIGER database for mapping with S. Two types of S maps, segment-based and polygon-based, are discussed along with methods to construct them from TIGER data. Polygon-based maps are useful for displaying regional statistical data; e.g., disease rates or incidence at the census tract level. Segment-based maps are easier to assemble and appropriate if the data are not regionalized. Census tract data of AIDS incidence in San Francisco (CA) and lung cancer case locations relative to petrochemical refinery sites in Contra Costa County (CA) are used to illustrate the methods and potential uses of interfacing the TIGER database with S.

  6. Fine Mapping Causal Variants with an Approximate Bayesian Method Using Marginal Test Statistics.

    PubMed

    Chen, Wenan; Larrabee, Beth R; Ovsyannikova, Inna G; Kennedy, Richard B; Haralambieva, Iana H; Poland, Gregory A; Schaid, Daniel J

    2015-07-01

    Two recently developed fine-mapping methods, CAVIAR and PAINTOR, demonstrate better performance over other fine-mapping methods. They also have the advantage of using only the marginal test statistics and the correlation among SNPs. Both methods leverage the fact that the marginal test statistics asymptotically follow a multivariate normal distribution and are likelihood based. However, their relationship with Bayesian fine mapping, such as BIMBAM, is not clear. In this study, we first show that CAVIAR and BIMBAM are actually approximately equivalent to each other. This leads to a fine-mapping method using marginal test statistics in the Bayesian framework, which we call CAVIAR Bayes factor (CAVIARBF). Another advantage of the Bayesian framework is that it can answer both association and fine-mapping questions. We also used simulations to compare CAVIARBF with other methods under different numbers of causal variants. The results showed that both CAVIARBF and BIMBAM have better performance than PAINTOR and other methods. Compared to BIMBAM, CAVIARBF has the advantage of using only marginal test statistics and takes about one-quarter to one-fifth of the running time. We applied different methods on two independent cohorts of the same phenotype. Results showed that CAVIARBF, BIMBAM, and PAINTOR selected the same top 3 SNPs; however, CAVIARBF and BIMBAM had better consistency in selecting the top 10 ranked SNPs between the two cohorts. Software is available at https://bitbucket.org/Wenan/caviarbf.

  7. Develop advanced nonlinear signal analysis topographical mapping system

    NASA Technical Reports Server (NTRS)

    1994-01-01

    The Space Shuttle Main Engine (SSME) has been undergoing extensive flight certification and developmental testing, which involves some 250 health monitoring measurements. Under the severe temperature, pressure, and dynamic environments sustained during operation, numerous major component failures have occurred, resulting in extensive engine hardware damage and scheduling losses. To enhance SSME safety and reliability, detailed analysis and evaluation of the measurements signal are mandatory to assess its dynamic characteristics and operational condition. Efficient and reliable signal detection techniques will reduce catastrophic system failure risks and expedite the evaluation of both flight and ground test data, and thereby reduce launch turn-around time. The basic objective of this contract are threefold: (1) develop and validate a hierarchy of innovative signal analysis techniques for nonlinear and nonstationary time-frequency analysis. Performance evaluation will be carried out through detailed analysis of extensive SSME static firing and flight data. These techniques will be incorporated into a fully automated system; (2) develop an advanced nonlinear signal analysis topographical mapping system (ATMS) to generate a Compressed SSME TOPO Data Base (CSTDB). This ATMS system will convert tremendous amount of complex vibration signals from the entire SSME test history into a bank of succinct image-like patterns while retaining all respective phase information. High compression ratio can be achieved to allow minimal storage requirement, while providing fast signature retrieval, pattern comparison, and identification capabilities; and (3) integrate the nonlinear correlation techniques into the CSTDB data base with compatible TOPO input data format. Such integrated ATMS system will provide the large test archives necessary for quick signature comparison. This study will provide timely assessment of SSME component operational status, identify probable causes of

  8. Develop advanced nonlinear signal analysis topographical mapping system

    NASA Technical Reports Server (NTRS)

    Jong, Jen-Yi

    1993-01-01

    The SSME has been undergoing extensive flight certification and developmental testing, which involves some 250 health monitoring measurements. Under the severe temperature pressure, and dynamic environments sustained during operation, numerous major component failures have occurred, resulting in extensive engine hardware damage and scheduling losses. To enhance SSME safety and reliability, detailed analysis and evaluation of the measurements signal are mandatory to assess its dynamic characteristics and operational condition. Efficient and reliable signal detection techniques will reduce catastrophic system failure risks and expedite the evaluation of both flight and ground test data, and thereby reduce launch turn-around time. The basic objective of this contract are threefold: (1) Develop and validate a hierarchy of innovative signal analysis techniques for nonlinear and nonstationary time-frequency analysis. Performance evaluation will be carried out through detailed analysis of extensive SSME static firing and flight data. These techniques will be incorporated into a fully automated system. (2) Develop an advanced nonlinear signal analysis topographical mapping system (ATMS) to generate a Compressed SSME TOPO Data Base (CSTDB). This ATMS system will convert tremendous amounts of complex vibration signals from the entire SSME test history into a bank of succinct image-like patterns while retaining all respective phase information. A high compression ratio can be achieved to allow the minimal storage requirement, while providing fast signature retrieval, pattern comparison, and identification capabilities. (3) Integrate the nonlinear correlation techniques into the CSTDB data base with compatible TOPO input data format. Such integrated ATMS system will provide the large test archives necessary for a quick signature comparison. This study will provide timely assessment of SSME component operational status, identify probable causes of malfunction, and indicate

  9. Statistical mapping of sheet aiquile SE-20-9 (national map) making use of ERTS images

    NASA Technical Reports Server (NTRS)

    Torrez, J. G.; Brockman, C. E.; Castro, A. F.

    1977-01-01

    New possibilities of remote sensing by means of satellites to do research on natural resources are reported. These images make it possible to carry out integrated studies of natural resources in the shortest time possible and with small investments. Various maps and a complete description of each are included. With the use of these satellites, scientists can hopefully plan development projects at the national level.

  10. How Narrative Focus and a Statistical Map Shape Health Policy Support Among State Legislators.

    PubMed

    Niederdeppe, Jeff; Roh, Sungjong; Dreisbach, Caitlin

    2016-01-01

    This study attempts to advance theorizing about health policy advocacy with combinations of narrative focus and a statistical map in an attempt to increase state legislators' support for policies to address the issue of obesity by reducing food deserts. Specifically, we examine state legislators' responses to variations in narrative focus (individual vs. community) about causes and solutions for food deserts in U.S. communities, and a statistical map (presence vs. absence) depicting the prevalence of food deserts across the United States. Using a Web-based randomized experiment (N=496), we show that narrative focus and the statistical map interact to produce different patterns of cognitive response and support for policies to reduce the prevalence of food deserts. The presence of a statistical map showing the prevalence of food deserts in the United States appeared to matter only when combined with an individual narrative, offsetting the fact that the individual narrative in isolation produced fewer thoughts consistent with the story's persuasive goal and more counterarguments in opposition to environmental causes and solutions for obesity than other message conditions. The image did not have an impact when combined with a story describing a community at large. Cognitive responses fully mediated message effects on intended persuasive outcomes. We conclude by discussing the study's contributions to communication theory and practice.

  11. How Narrative Focus and a Statistical Map Shape Health Policy Support Among State Legislators.

    PubMed

    Niederdeppe, Jeff; Roh, Sungjong; Dreisbach, Caitlin

    2016-01-01

    This study attempts to advance theorizing about health policy advocacy with combinations of narrative focus and a statistical map in an attempt to increase state legislators' support for policies to address the issue of obesity by reducing food deserts. Specifically, we examine state legislators' responses to variations in narrative focus (individual vs. community) about causes and solutions for food deserts in U.S. communities, and a statistical map (presence vs. absence) depicting the prevalence of food deserts across the United States. Using a Web-based randomized experiment (N=496), we show that narrative focus and the statistical map interact to produce different patterns of cognitive response and support for policies to reduce the prevalence of food deserts. The presence of a statistical map showing the prevalence of food deserts in the United States appeared to matter only when combined with an individual narrative, offsetting the fact that the individual narrative in isolation produced fewer thoughts consistent with the story's persuasive goal and more counterarguments in opposition to environmental causes and solutions for obesity than other message conditions. The image did not have an impact when combined with a story describing a community at large. Cognitive responses fully mediated message effects on intended persuasive outcomes. We conclude by discussing the study's contributions to communication theory and practice. PMID:26086340

  12. Tables of square-law signal detection statistics for Hann spectra with 50 percent overlap

    NASA Technical Reports Server (NTRS)

    Deans, Stanley R.; Cullers, D. Kent

    1991-01-01

    The Search for Extraterrestrial Intelligence, currently being planned by NASA, will require that an enormous amount of data be analyzed in real time by special purpose hardware. It is expected that overlapped Hann data windows will play an important role in this analysis. In order to understand the statistical implication of this approach, it has been necessary to compute detection statistics for overlapped Hann spectra. Tables of signal detection statistics are given for false alarm rates from 10(exp -14) to 10(exp -1) and signal detection probabilities from 0.50 to 0.99; the number of computed spectra ranges from 4 to 2000.

  13. When a Map is Worth One-Thousand Anovas: Applications of Statistical Cartography in Special Education Research and Planning.

    ERIC Educational Resources Information Center

    Joiner, Lee Marvin

    1979-01-01

    The article describes the methods and procedures of computerized statistical cartography, the production of statistical maps, and provides suggestions for its application in special education research and planning. (Author/CL)

  14. Why a high statistical performance cannot be equated with a high plausibility of landslide susceptibility maps

    NASA Astrophysics Data System (ADS)

    Steger, Stefan; Brenning, Alexander; Bell, Rainer; Petschko, Helene; Glade, Thomas

    2015-04-01

    Statistical landslide susceptibility maps express a relative estimate of where landslides are more likely to occur in the future due to a set of geo-environmental conditions. Their predictive capability is regularly deduced by interpreting threshold independent performance measures like the area under the receiver operating characteristic curve (AUROC). These quantitative estimates frequently serve as a decision tool to favour a certain classifier over another and/or to select a suitable combination of predictors. Literature exposes that many authors consider their final maps as a valuable instrument for spatial planners and decision makers. However, most often the susceptibility maps are selected by solely interpreting such quantitative estimates. We assume that a high statistical quality is necessary but not sufficient in order to produce plausible landslide susceptibility maps. This assumption was tested by quantitatively and qualitatively validating 16 susceptibility models for a study area (1354 km²) located in Lower Austria. The models were generated by applying two statistical and two machine learning classifiers separately for two landslide inventories and two sets of predictors. Quantitative validation was conducted by estimating the AUROC with non spatial hold-out validation and a repeated spatial cross validation technique. The spatial differentiation of the final maps was evaluated at different scales by interpreting semivariograms. Maps of the location of major variations illustrate the spatial structure of the final susceptibility maps and allowed to deduce the most influential predictors and predictor classes. According to the hold-out validation, all 16 susceptibility models performed similarly well. However, spatial cross validation revealed considerable differences between models generated by different landslide inventories. Semivariograms exposed that the predicted landslide susceptibility pattern differs substantially between maps generated by

  15. Detecting missing signals in multichannel recordings by using higher order statistics.

    PubMed

    Halabi, R; Diab, M O; Moslem, B; Khalil, M; Marque, C

    2012-01-01

    In real world applications, a multichannel acquisition system is susceptible of having one or many of its sensors displaced or detached, leading therefore to the loss or corruption of the recorded signals. In this paper, we present a technique for detecting missing or corrupted signals in multichannel recordings. Our approach is based on Higher Order Statistics (HOS) analysis. Our approach is tested on real uterine electromyogram (EMG) signals recorded by 4×4 electrode grid. Results have shown that HOS descriptors can discriminate between the two classes of signals (missing vs. non-missing). These results are supported by statistical analysis using the t-test which indicated good statistical significance of 95% confidence level.

  16. Integrating field sampling, spatial statistics and remote sensing to map wetland vegetation in the Pantanal, Brazil

    NASA Astrophysics Data System (ADS)

    Arieira, J.; Karssenberg, D.; de Jong, S. M.; Addink, E. A.; Couto, E. G.; Nunes da Cunha, C.; Skøien, J. O.

    2010-09-01

    To improve the protection of wetlands, it is imperative to have a thorough understanding of their structuring elements and of the identification of efficient methods to describe and monitor them. This article uses sophisticated statistical classification, interpolation and error propagation techniques, in order to describe vegetation spatial patterns, map plant community distribution and evaluate the capability of statistical approaches to produce high-quality vegetation maps. The approach results in seven vegetation communities with a known floral composition that can be mapped over large areas using remotely sensed data. The relations between remotely sensing data and vegetation patterns, captured in four factorial axes, were formalized mathematically in multiple linear regression models and used in a universal kriging procedure to reduce the uncertainty in mapped communities. Universal kriging has shown to be a valuable interpolation technique because parts of vegetation variability not explained by the images could be modeled as spatially correlated residuals, increasing prediction accuracy. Differences in spatial dependence of the vegetation gradients evidenced the multi-scale nature of vegetation communities. Cross validation procedures and Monte Carlo simulations were used to quantify the uncertainty in the resulting map. Cross-validation showed that accuracy in classification varies according with the community type, as a result of sampling density and configuration. A map of uncertainty resulted from Monte Carlo simulations displayed the spatial variation in classification accuracy, showing that the quality of classification varies spatially, even though the proportion and arrangement of communities observed in the original map is preserved to a great extent. These results suggested that mapping improvement could be achieved by increasing the number of field observations of those communities with a scattered and small patch size distribution; or by

  17. Description and comparison of geologic maps with FRAGSTATS - A spatial statistics program

    USGS Publications Warehouse

    Raines, G.L.

    2002-01-01

    FRAGSTATS is a public-domain GIS implementation of a set of spatial statistics that address a fundamental problem in GIS applications, description and comparison of maps. The spatial statistics from the 1:2,500,000-scale United States geologic map of Nevada, the central United States, and the northeastern United States quantify the differences in complexity and variability between these three geologic terranes. Nevada is defined by a large number of patches of small size and low size variability, whereas the Central area has a small number of patches with smaller relative size variability. All three areas have similar map-unit shape complexity with Nevada having the lowest. Based on the density of edges, the areas can be ranked from highest to lowest, as Nevada, Central, and Northeast. The Shannon diversity index ranks the areas from highest to lowest, as Northeast, Nevada, and Central, but the Shannon evenness index ranks them from highest to lowest, as Northeast, Central, and Nevada. These rankings may reflect the influence of folding in the Northeast and Central areas as opposed to basin and range extension in Nevada. The core areas statistic ranks the areas for spatial accuracy from highest to lowest, as Central, Northeast, and Nevada, with Northeast and Nevada being similar. For a scale comparison, the FRAGSTATS statistics quantify the increased complexity and spatial accuracy that is inherent in going from small- to larger-scale maps. For example for 1:2,500,000-1:500,000-scale maps of Nevada, respectively, the area weighted fractal dimension increase from 1.1 to 1.18, and the total core areas index almost doubles from 39.09 to 63.38. In addition, the fractal dimensions discriminate gross lithology and tectonic terranes. ?? 2002 Elsevier Science Ltd. All rights reserved.

  18. Description and comparison of geologic maps with FRAGSTATS—a spatial statistics program

    NASA Astrophysics Data System (ADS)

    Raines, Gary L.

    2002-02-01

    FRAGSTATS is a public-domain GIS implementation of a set of spatial statistics that address a fundamental problem in GIS applications, description and comparison of maps. The spatial statistics from the 1 : 2,500,000-scale United States geologic map of Nevada, the central United States, and the northeastern United States quantify the differences in complexity and variability between these three geologic terranes. Nevada is defined by a large number of patches of small size and low size variability, whereas the Central area has a small number of patches with smaller relative size variability. All three areas have similar map-unit shape complexity with Nevada having the lowest. Based on the density of edges, the areas can be ranked from highest to lowest, as Nevada, Central, and Northeast. The Shannon diversity index ranks the areas from highest to lowest, as Northeast, Nevada, and Central, but the Shannon evenness index ranks them from highest to lowest, as Northeast, Central, and Nevada. These rankings may reflect the influence of folding in the Northeast and Central areas as opposed to basin and range extension in Nevada. The core areas statistic ranks the areas for spatial accuracy from highest to lowest, as Central, Northeast, and Nevada, with Northeast and Nevada being similar. For a scale comparison, the FRAGSTATS statistics quantify the increased complexity and spatial accuracy that is inherent in going from small- to larger-scale maps. For example for 1 : 2,500,000-1 : 500,000-scale maps of Nevada, respectively, the area weighted fractal dimension increases from 1.1 to 1.18, and the total core areas index almost doubles from 39.09 to 63.38. In addition, the fractal dimensions discriminate gross lithology and tectonic terranes.

  19. Comments on the statistical analysis of excess variance in the COBE differential microwave radiometer maps

    NASA Astrophysics Data System (ADS)

    Wright, E. L.; Smoot, G. F.; Kogut, A.; Hinshaw, G.; Tenorio, L.; Lineweaver, C.; Bennett, C. L.; Lubin, P. M.

    1994-01-01

    Cosmic anisotrophy produces an excess variance sq sigmasky in the Delta maps produced by the Differential Microwave Radiometer (DMR) on cosmic background explorer (COBE) that is over and above the instrument noise. After smoothing to an effective resolution of 10 deg, this excess sigmasky(10 deg), provides an estimate for the amplitude of the primordial density perturbation power spectrum with a cosmic uncertainty of only 12%. We employ detailed Monte Carlo techniques to express the amplitude derived from this statistic in terms of the universal root mean square (rms) quadrupole amplitude, (Q sq/RMS)0.5. The effects of monopole and dipole subtraction and the non-Gaussian shape of the DMR beam cause the derived (Q sq/RMS)0.5 to be 5%-10% larger than would be derived using simplified analytic approximations. We also investigate the properties of two other map statistics: the actual quadrupole and the Boughn-Cottingham statistic. Both the sigmasky(10 deg) statistic and the Boughn-Cottingham statistic are consistent with the (Q sq/RMS)0.5 = 17 +/- 5 micro K reported by Smoot et al. (1992) and Wright et al. (1992).

  20. Current practices in spatial analysis of cancer data: mapping health statistics to inform policymakers and the public

    PubMed Central

    Bell, B Sue; Hoskins, Richard E; Pickle, Linda Williams; Wartenberg, Daniel

    2006-01-01

    Background To communicate population-based cancer statistics, cancer researchers have a long tradition of presenting data in a spatial representation, or map. Historically, health data were presented in printed atlases in which the map producer selected the content and format. The availability of geographic information systems (GIS) with comprehensive mapping and spatial analysis capability for desktop and Internet mapping has greatly expanded the number of producers and consumers of health maps, including policymakers and the public. Because health maps, particularly ones that show elevated cancer rates, historically have raised public concerns, it is essential that these maps be designed to be accurate, clear, and interpretable for the broad range of users who may view them. This article focuses on designing maps to communicate effectively. It is based on years of research into the use of health maps for communicating among public health researchers. Results The basics for designing maps that communicate effectively are similar to the basics for any mode of communication. Tasks include deciding on the purpose, knowing the audience and its characteristics, choosing a media suitable for both the purpose and the audience, and finally testing the map design to ensure that it suits the purpose with the intended audience, and communicates accurately and effectively. Special considerations for health maps include ensuring confidentiality and reflecting the uncertainty of small area statistics. Statistical maps need to be based on sound practices and principles developed by the statistical and cartographic communities. Conclusion The biggest challenge is to ensure that maps of health statistics inform without misinforming. Advances in the sciences of cartography, statistics, and visualization of spatial data are constantly expanding the toolkit available to mapmakers to meet this challenge. Asking potential users to answer questions or to talk about what they see is

  1. Landslide susceptibility mapping using GIS-based statistical models and Remote sensing data in tropical environment.

    PubMed

    Shahabi, Himan; Hashim, Mazlan

    2015-04-22

    This research presents the results of the GIS-based statistical models for generation of landslide susceptibility mapping using geographic information system (GIS) and remote-sensing data for Cameron Highlands area in Malaysia. Ten factors including slope, aspect, soil, lithology, NDVI, land cover, distance to drainage, precipitation, distance to fault, and distance to road were extracted from SAR data, SPOT 5 and WorldView-1 images. The relationships between the detected landslide locations and these ten related factors were identified by using GIS-based statistical models including analytical hierarchy process (AHP), weighted linear combination (WLC) and spatial multi-criteria evaluation (SMCE) models. The landslide inventory map which has a total of 92 landslide locations was created based on numerous resources such as digital aerial photographs, AIRSAR data, WorldView-1 images, and field surveys. Then, 80% of the landslide inventory was used for training the statistical models and the remaining 20% was used for validation purpose. The validation results using the Relative landslide density index (R-index) and Receiver operating characteristic (ROC) demonstrated that the SMCE model (accuracy is 96%) is better in prediction than AHP (accuracy is 91%) and WLC (accuracy is 89%) models. These landslide susceptibility maps would be useful for hazard mitigation purpose and regional planning.

  2. Landslide susceptibility mapping using GIS-based statistical models and Remote sensing data in tropical environment.

    PubMed

    Shahabi, Himan; Hashim, Mazlan

    2015-01-01

    This research presents the results of the GIS-based statistical models for generation of landslide susceptibility mapping using geographic information system (GIS) and remote-sensing data for Cameron Highlands area in Malaysia. Ten factors including slope, aspect, soil, lithology, NDVI, land cover, distance to drainage, precipitation, distance to fault, and distance to road were extracted from SAR data, SPOT 5 and WorldView-1 images. The relationships between the detected landslide locations and these ten related factors were identified by using GIS-based statistical models including analytical hierarchy process (AHP), weighted linear combination (WLC) and spatial multi-criteria evaluation (SMCE) models. The landslide inventory map which has a total of 92 landslide locations was created based on numerous resources such as digital aerial photographs, AIRSAR data, WorldView-1 images, and field surveys. Then, 80% of the landslide inventory was used for training the statistical models and the remaining 20% was used for validation purpose. The validation results using the Relative landslide density index (R-index) and Receiver operating characteristic (ROC) demonstrated that the SMCE model (accuracy is 96%) is better in prediction than AHP (accuracy is 91%) and WLC (accuracy is 89%) models. These landslide susceptibility maps would be useful for hazard mitigation purpose and regional planning. PMID:25898919

  3. Landslide susceptibility mapping using GIS-based statistical models and Remote sensing data in tropical environment

    PubMed Central

    Hashim, Mazlan

    2015-01-01

    This research presents the results of the GIS-based statistical models for generation of landslide susceptibility mapping using geographic information system (GIS) and remote-sensing data for Cameron Highlands area in Malaysia. Ten factors including slope, aspect, soil, lithology, NDVI, land cover, distance to drainage, precipitation, distance to fault, and distance to road were extracted from SAR data, SPOT 5 and WorldView-1 images. The relationships between the detected landslide locations and these ten related factors were identified by using GIS-based statistical models including analytical hierarchy process (AHP), weighted linear combination (WLC) and spatial multi-criteria evaluation (SMCE) models. The landslide inventory map which has a total of 92 landslide locations was created based on numerous resources such as digital aerial photographs, AIRSAR data, WorldView-1 images, and field surveys. Then, 80% of the landslide inventory was used for training the statistical models and the remaining 20% was used for validation purpose. The validation results using the Relative landslide density index (R-index) and Receiver operating characteristic (ROC) demonstrated that the SMCE model (accuracy is 96%) is better in prediction than AHP (accuracy is 91%) and WLC (accuracy is 89%) models. These landslide susceptibility maps would be useful for hazard mitigation purpose and regional planning. PMID:25898919

  4. Statistical analysis of surrogate signals to incorporate respiratory motion variability into radiotherapy treatment planning

    NASA Astrophysics Data System (ADS)

    Wilms, Matthias; Ehrhardt, Jan; Werner, René; Marx, Mirko; Handels, Heinz

    2014-03-01

    Respiratory motion and its variability lead to location uncertainties in radiation therapy (RT) of thoracic and abdominal tumors. Current approaches for motion compensation in RT are usually driven by respiratory surrogate signals, e.g., spirometry. In this contribution, we present an approach for statistical analysis, modeling and subsequent simulation of surrogate signals on a cycle-by-cycle basis. The simulated signals represent typical patient-specific variations of, e.g., breathing amplitude and cycle period. For the underlying statistical analysis, all breathing cycles of an observed signal are consistently parameterized using approximating B-spline curves. Statistics on breathing cycles are then performed by using the parameters of the B-spline approximations. Assuming that these parameters follow a multivariate Gaussian distribution, realistic time-continuous surrogate signals of arbitrary length can be generated and used to simulate the internal motion of tumors and organs based on a patient-specific diffeomorphic correspondence model. As an example, we show how this approach can be employed in RT treatment planning to calculate tumor appearance probabilities and to statistically assess the impact of respiratory motion and its variability on planned dose distributions.

  5. Efficient and Statistically Valid Method of Textural Sea Floor Characterization in Benthic Habitat Mapping

    NASA Astrophysics Data System (ADS)

    Kostylev, V. E.; Orpin, A. R.

    2004-12-01

    The advent of multibeam bathymetric sonar technology and the thematic development of benthic habitat research have spawned renewed interest in the systematic characterization and mapping of the seafloor. This necessitates the application of reliable and accurate sea floor descriptors in combination with a robust means to statistically assess descriptor associations. Traditionally, geoscientific sea floor mapping was comprised primarily of identifying the spatial extent and relationship of geological units, broadly following chronostratigraphic conventions. Classifying seafloor sediments using geological facies may not be meaningful biologically because they incorporate temporal elements that stem from a geochronological qualifier. Textural properties of geological facies are typically reliant on the application of distribution-dependent statistics, which have been shown to be inappropriate with multimodal marine sediments. While the relationship between grain size and biota appears self-evident, there is a compelling argument that granulometric properites alone are not a determinant of species distribution or community composition. The classification process is problematic because most statistical clustering techniques will, by their very nature, form clusters which may or may not represent meaningful and discernable differences. Moreover, as habitat mapping is aimed at boundary definition, the boundaries between clusters in such cases could be based on very subtle differences, or noise (e.g. sampling bias). An independent measure of the appropriate number of groups in a dataset is required. Therefore, we examine a statistical approach pioneered by Calinski & Harabasz (C-H), which was implemented by a computer routine to work in partnership with information entropy analysis of grain size data. We utilize a 30-year legacy of grain size data collected from the Scotian Shelf, Canadian Atlantic continental margin, and show that considerable improvements in textural

  6. Accuracy Evaluation of a Mobile Mapping System with Advanced Statistical Methods

    NASA Astrophysics Data System (ADS)

    Toschi, I.; Rodríguez-Gonzálvez, P.; Remondino, F.; Minto, S.; Orlandini, S.; Fuller, A.

    2015-02-01

    This paper discusses a methodology to evaluate the precision and the accuracy of a commercial Mobile Mapping System (MMS) with advanced statistical methods. So far, the metric potentialities of this emerging mapping technology have been studied in few papers, where generally the assumption that errors follow a normal distribution is made. In fact, this hypothesis should be carefully verified in advance, in order to test how well the Gaussian classic statistics can adapt to datasets that are usually affected by asymmetrical gross errors. The workflow adopted in this study relies on a Gaussian assessment, followed by an outlier filtering process. Finally, non-parametric statistical models are applied, in order to achieve a robust estimation of the error dispersion. Among the different MMSs available on the market, the latest solution provided by RIEGL is here tested, i.e. the VMX-450 Mobile Laser Scanning System. The test-area is the historic city centre of Trento (Italy), selected in order to assess the system performance in dealing with a challenging and historic urban scenario. Reference measures are derived from photogrammetric and Terrestrial Laser Scanning (TLS) surveys. All datasets show a large lack of symmetry that leads to the conclusion that the standard normal parameters are not adequate to assess this type of data. The use of non-normal statistics gives thus a more appropriate description of the data and yields results that meet the quoted a-priori errors.

  7. Report on 3 and 4-point correlation statistics in the COBE DMR anisotrophy maps

    NASA Technical Reports Server (NTRS)

    Hinshaw, Gary (Principal Investigator); Gorski, Krzystof M.; Banday, Anthony J.; Bennett, Charles L.

    1996-01-01

    As part of the work performed under NASA contract # NAS5-32648, we have computed the 3-point and 4-point correlation functions of the COBE-DNIR 2-year and 4-year anisotropy maps. The motivation for this study was to search for evidence of non-Gaussian statistical fluctuations in the temperature maps: skewness or asymmetry in the case of the 3-point function, kurtosis in the case of the 4-point function. Such behavior would have very significant implications for our understanding of the processes of galaxy formation, because our current models of galaxy formation predict that non-Gaussian features should not be present in the DMR maps. The results of our work showed that the 3-point correlation function is consistent with zero and that the 4-point function is not a very sensitive probe of non-Gaussian behavior in the COBE-DMR data. Our computation and analysis of 3-point correlations in the 2-year DMR maps was published in the Astrophysical Journal Letters, volume 446, page L67, 1995. Our computation and analysis of 3-point correlations in the 4-year DMR maps will be published, together with some additional tests, in the June 10, 1996 issue of the Astrophysical Journal Letters. Copies of both of these papers are attached as an appendix to this report.

  8. Recurrence-time statistics in non-Hamiltonian volume-preserving maps and flows.

    PubMed

    da Silva, Rafael M; Beims, Marcus W; Manchein, Cesar

    2015-08-01

    We analyze the recurrence-time statistics (RTS) in three-dimensional non-Hamiltonian volume-preserving systems (VPS): an extended standard map and a fluid model. The extended map is a standard map weakly coupled to an extra dimension which contains a deterministic regular, mixed (regular and chaotic), or chaotic motion. The extra dimension strongly enhances the trapping times inducing plateaus and distinct algebraic and exponential decays in the RTS plots. The combined analysis of the RTS with the classification of ordered and chaotic regimes and scaling properties allows us to describe the intricate way trajectories penetrate the previously impenetrable regular islands from the uncoupled case. Essentially the plateaus found in the RTS are related to trajectories that stay for long times inside trapping tubes, not allowing recurrences, and then penetrate diffusively the islands (from the uncoupled case) by a diffusive motion along such tubes in the extra dimension. All asymptotic exponential decays for the RTS are related to an ordered regime (quasiregular motion), and a mixing dynamics is conjectured for the model. These results are compared to the RTS of the standard map with dissipation or noise, showing the peculiarities obtained by using three-dimensional VPS. We also analyze the RTS for a fluid model and show remarkable similarities to the RTS in the extended standard map problem. PMID:26382489

  9. GIS-based statistical mapping technique for block-and-ash pyroclastic flow and surge hazards

    NASA Astrophysics Data System (ADS)

    Widiwijayanti, C.; Voight, B.; Hidayat, D.; Schilling, S.

    2008-12-01

    Assessments of pyroclastic flow (PF) hazards are commonly based on mapping of PF and surge deposits and estimations of inundation limits, and/or computer models of varying degrees of sophistication. In volcanic crises a PF hazard map may be sorely needed, but limited time, exposures, or safety aspects may preclude fieldwork, and insufficient time or baseline data may be available for reliable dynamic simulations. We have developed a statistically constrained simulation model for block-and-ash PFs to estimate potential areas of inundation by adapting methodology from Iverson et al. (1998) for lahars. The predictive equations for block-and-ash PFs are calibrated with data from many volcanoes and given by A = (0.05-0.1)V2/3, B = (35-40)V2/3 , where A is cross-sectional area of inundation, B is planimetric area and V is deposit volume. The proportionality coefficients were obtained from regression analyses and comparison of simulations to mapped deposits. The method embeds the predictive equations in a GIS program coupled with DEM topography, using the LAHARZ program of Schilling (1998). Although the method is objective and reproducible, any PF hazard zone so computed should be considered as an approximate guide only, due to uncertainties on coefficients applicable to individual PFs, DEM details, and release volumes. Gradational nested hazard maps produced by these simulations reflect in a sense these uncertainties. The model does not explicitly consider dynamic behavior, which can be important. Surge impacts must be extended beyond PF hazard zones and we have explored several approaches to do this. The method has been used to supply PF hazard maps in two crises: Merapi 2006; and Montserrat 2006- 2007. We have also compared our hazard maps to actual recent PF deposits and to maps generated by several other model techniques.

  10. Selective regulation of MAP kinase signaling by an endomembrane phosphatidylinositol 4-kinase.

    PubMed

    Cappell, Steven D; Dohlman, Henrik G

    2011-04-29

    Multiple MAP kinase pathways share components yet initiate distinct biological processes. Signaling fidelity can be maintained by scaffold proteins and restriction of signaling complexes to discreet subcellular locations. For example, the yeast MAP kinase scaffold Ste5 binds to phospholipids produced at the plasma membrane and promotes selective MAP kinase activation. Here we show that Pik1, a phosphatidylinositol 4-kinase that localizes primarily to the Golgi, also regulates MAP kinase specificity but does so independently of Ste5. Pik1 is required for full activation of the MAP kinases Fus3 and Hog1 and represses activation of Kss1. Further, we show by genetic epistasis analysis that Pik1 likely regulates Ste11 and Ste50, components shared by all three MAP kinase pathways, through their interaction with the scaffold protein Opy2. These findings reveal a new regulator of signaling specificity functioning at endomembranes rather than at the plasma membrane. PMID:21388955

  11. Quantification of Liver Tumors Using Statistical Characteristics of Ultrasonic RF Signals

    NASA Astrophysics Data System (ADS)

    Chono, Tomoaki; Ito, Masayasu

    We propose a method for quantification of liver tumors using statistical characteristics of ultrasonic RF signals. Parameters of K distribution show the characteristics of a soft tissue. The proposed method of chi-square test(CST) can estimate the most appropriate parameters of K distribution, which are fitted to an observed amplitude distribution. Method of moment(MOM), method combining maximum likelihood and MOM(ML/MOM), and CST are compared on simulated RF signals. The CST is applied to RF signals of liver tumors including 38 hepatocellular carcinomas(malignancy) and 12 hepatic hemangiomas(benignancy). The accuracy of discriminant analysis are 78% and 50% for malignancy and benignancy, respectively.

  12. Influence of the normalization template on the outcome of statistical parametric mapping of PET scans.

    PubMed

    Gispert, J D; Pascau, J; Reig, S; Martínez-Lázaro, R; Molina, V; García-Barreno, P; Desco, M

    2003-07-01

    Spatial normalization is an essential preprocessing step in statistical parametric mapping (SPM)-based analysis of PET scans. The standard template provided with the SPM99 software package was originally constructed using (15)O-H(2)O PET scans and is commonly applied regardless of the tracer actually used in the scans being analyzed. This work studies the effect of using three different normalization templates in the outcome of the statistical analysis of PET scans: (1) the standard SPM99 PET template; (2) an (18)F-FDG PET template, constructed by averaging PET scans previously normalized to the standard template; and (3) an MRI-aided (18)F-FDG PET template, constructed by averaging PET scans normalized according to the deformation parameters obtained from MRI scans. A strictly anatomical MRI normalization of each PET was used as a reference, under the rationale that a normalization based only upon MRI should provide higher spatial accuracy. The potential bias involved in the normalization process was estimated in a clinical SPM study comparing schizophrenic patients with control subjects. For each between-group comparison, three SPM maps were obtained, one for each template. To evaluate the influence of the template, these SPM maps were compared to the reference SPM map achieved using the anatomical normalization. SPMs obtained by MRI-aided normalization showed the highest spatial specificity, and also higher sensitivity when compared to the standard normalization using the SPM99 (15)O-H(2)O template. These results show that the use of the standard template under inappropriate conditions (different tracer or mental state) may lead to inconsistent interpretations of the statistical analysis.

  13. Exploring discrepancies between quantitative validation results and the geomorphic plausibility of statistical landslide susceptibility maps

    NASA Astrophysics Data System (ADS)

    Steger, Stefan; Brenning, Alexander; Bell, Rainer; Petschko, Helene; Glade, Thomas

    2016-06-01

    Empirical models are frequently applied to produce landslide susceptibility maps for large areas. Subsequent quantitative validation results are routinely used as the primary criteria to infer the validity and applicability of the final maps or to select one of several models. This study hypothesizes that such direct deductions can be misleading. The main objective was to explore discrepancies between the predictive performance of a landslide susceptibility model and the geomorphic plausibility of subsequent landslide susceptibility maps while a particular emphasis was placed on the influence of incomplete landslide inventories on modelling and validation results. The study was conducted within the Flysch Zone of Lower Austria (1,354 km2) which is known to be highly susceptible to landslides of the slide-type movement. Sixteen susceptibility models were generated by applying two statistical classifiers (logistic regression and generalized additive model) and two machine learning techniques (random forest and support vector machine) separately for two landslide inventories of differing completeness and two predictor sets. The results were validated quantitatively by estimating the area under the receiver operating characteristic curve (AUROC) with single holdout and spatial cross-validation technique. The heuristic evaluation of the geomorphic plausibility of the final results was supported by findings of an exploratory data analysis, an estimation of odds ratios and an evaluation of the spatial structure of the final maps. The results showed that maps generated by different inventories, classifiers and predictors appeared differently while holdout validation revealed similar high predictive performances. Spatial cross-validation proved useful to expose spatially varying inconsistencies of the modelling results while additionally providing evidence for slightly overfitted machine learning-based models. However, the highest predictive performances were obtained for

  14. Problems Associated with Statistical Pattern Recognition of Acoustic Emission Signals in a Compact Tension Fatigue Specimen

    NASA Technical Reports Server (NTRS)

    Hinton, Yolanda L.

    1999-01-01

    Acoustic emission (AE) data were acquired during fatigue testing of an aluminum 2024-T4 compact tension specimen using a commercially available AE system. AE signals from crack extension were identified and separated from noise spikes, signals that reflected from the specimen edges, and signals that saturated the instrumentation. A commercially available software package was used to train a statistical pattern recognition system to classify the signals. The software trained a network to recognize signals with a 91-percent accuracy when compared with the researcher's interpretation of the data. Reasons for the discrepancies are examined and it is postulated that additional preprocessing of the AE data to focus on the extensional wave mode and eliminate other effects before training the pattern recognition system will result in increased accuracy.

  15. c-Jun controls the efficiency of MAP kinase signaling by transcriptional repression of MAP kinase phosphatases

    SciTech Connect

    Sprowles, Amy; Wu Yimi; Kung, H.-J.; Wisdom, Ron . E-mail: ronald.wisdom@ucdmc.ucdavis.edu

    2005-08-15

    The mammalian JNK signaling pathway regulates the transcriptional response of cells to environmental stress, including UV irradiation. This signaling pathway is composed of a classical MAP kinase cascade; activation results in phosphorylation of the transcription factor substrates c-Jun and ATF2, and leads to changes in gene expression. The defining components of this pathway are conserved in the fission yeast S. pombe, where the genetic studies have shown that the ability of the JNK homolog Spc1 to be activated in response to UV irradiation is dependent on the presence of the transcription factor substrate Atf1. We have used genetic analysis to define the role of c-Jun in activation of the mammalian JNK signaling pathway. Our results show that optimal activation of JNK requires the presence of its transcription factor substrate c-Jun. Mutational analysis shows that the ability of c-Jun to support efficient activation of JNK requires the ability of Jun to bind DNA, suggesting a transcriptional mechanism. Consistent with this, we show that c-Jun represses the expression of several MAP kinase phosphatases. In the absence of c-Jun, the increased expression of MAP kinase phosphatases leads to impaired activation of the ERK, JNK, and p38 MAP kinases after pathway activation. The results show that one function of c-Jun is to regulate the efficiency of signaling by the ERK, p38, and JNK MAP kinases, a function that is likely to affect cellular responses to many different stimuli.

  16. Statistical wall shear stress maps of ruptured and unruptured middle cerebral artery aneurysms

    PubMed Central

    Goubergrits, L.; Schaller, J.; Kertzscher, U.; van den Bruck, N.; Poethkow, K.; Petz, Ch.; Hege, H.-Ch.; Spuler, A.

    2012-01-01

    Haemodynamics and morphology play an important role in the genesis, growth and rupture of cerebral aneurysms. The goal of this study was to generate and analyse statistical wall shear stress (WSS) distributions and shapes in middle cerebral artery (MCA) saccular aneurysms. Unsteady flow was simulated in seven ruptured and 15 unruptured MCA aneurysms. In order to compare these results, all geometries must be brought in a uniform coordinate system. For this, aneurysms with corresponding WSS data were transformed into a uniform spherical shape; then, all geometries were uniformly aligned in three-dimensional space. Subsequently, we compared statistical WSS maps and surfaces of ruptured and unruptured aneurysms. No significant (p > 0.05) differences exist between ruptured and unruptured aneurysms regarding radius and mean WSS. In unruptured aneurysms, statistical WSS map relates regions with high (greater than 3 Pa) WSS to the neck region. In ruptured aneurysms, additional areas with high WSS contiguous to regions of low (less than 1 Pa) WSS are found in the dome region. In ruptured aneurysms, we found significantly lower WSS. The averaged aneurysm surface of unruptured aneurysms is round shaped, whereas the averaged surface of ruptured cases is multi-lobular. Our results confirm the hypothesis of low WSS and irregular shape as the essential rupture risk parameters. PMID:21957117

  17. Deriving statistical significance maps for SVM based image classification and group comparisons.

    PubMed

    Gaonkar, Bilwaj; Davatzikos, Christos

    2012-01-01

    Population based pattern analysis and classification for quantifying structural and functional differences between diverse groups has been shown to be a powerful tool for the study of a number of diseases, and is quite commonly used especially in neuroimaging. The alternative to these pattern analysis methods, namely mass univariate methods such as voxel based analysis and all related methods, cannot detect multivariate patterns associated with group differences, and are not particularly suitable for developing individual-based diagnostic and prognostic biomarkers. A commonly used pattern analysis tool is the support vector machine (SVM). Unlike univariate statistical frameworks for morphometry, analytical tools for statistical inference are unavailable for the SVM. In this paper, we show that null distributions ordinarily obtained by permutation tests using SVMs can be analytically approximated from the data. The analytical computation takes a small fraction of the time it takes to do an actual permutation test, thereby rendering it possible to quickly create statistical significance maps derived from SVMs. Such maps are critical for understanding imaging patterns of group differences and interpreting which anatomical regions are important in determining the classifier's decision.

  18. The spatial statistics formalism applied to mapping electromagnetic radiation in urban areas.

    PubMed

    Paniagua, Jesus M; Rufo, Montaña; Jimenez, Antonio; Antolin, Alicia

    2013-01-01

    Determining the electromagnetic radiation levels in urban areas is a complicated task. Various approaches have been taken, including numerical simulations using different models of propagation, sampling campaigns to measure field values with which to validate theoretical models, and the formalism of spatial statistics. In the work, we present here that this latter technique was used to construct maps of electric field and its associated uncertainty from experimental data. For this purpose, a field meter and a broadband probe sensitive in the 100-kHz-3-GHz frequency range were used to take 1,020 measurements around buildings and along the perimeter of the area. The distance between sampling points was 5 m. The results were stored in a geographic information system to facilitate data handling and analysis, in particular, the application of the formalism of spatial statistical to the analysis of the distribution of the field levels over the study area. The spatial structure was analyzed using the variographic technique, with the field levels at non-sampled points being interpolated by kriging. The results indicated that, in the urban area analyzed in the present work, the linear density of sampling points could be reduced to a distance which coincides with the length of the blocks of buildings without the statistical parameters varying significantly and with the field level maps being reproduced qualitatively and quantitatively.

  19. MAP Support Detection for Greedy Sparse Signal Recovery Algorithms in Compressive Sensing

    NASA Astrophysics Data System (ADS)

    Lee, Namyoon

    2016-10-01

    A reliable support detection is essential for a greedy algorithm to reconstruct a sparse signal accurately from compressed and noisy measurements. This paper proposes a novel support detection method for greedy algorithms, which is referred to as "\\textit{maximum a posteriori (MAP) support detection}". Unlike existing support detection methods that identify support indices with the largest correlation value in magnitude per iteration, the proposed method selects them with the largest likelihood ratios computed under the true and null support hypotheses by simultaneously exploiting the distributions of sensing matrix, sparse signal, and noise. Leveraging this technique, MAP-Matching Pursuit (MAP-MP) is first presented to show the advantages of exploiting the proposed support detection method, and a sufficient condition for perfect signal recovery is derived for the case when the sparse signal is binary. Subsequently, a set of iterative greedy algorithms, called MAP-generalized Orthogonal Matching Pursuit (MAP-gOMP), MAP-Compressive Sampling Matching Pursuit (MAP-CoSaMP), and MAP-Subspace Pursuit (MAP-SP) are presented to demonstrate the applicability of the proposed support detection method to existing greedy algorithms. From empirical results, it is shown that the proposed greedy algorithms with highly reliable support detection can be better, faster, and easier to implement than basis pursuit via linear programming.

  20. Statistical parametric mapping in brain single photon computed emission tomography after carbon monoxide intoxication.

    PubMed

    Watanabe, N; Nohara, S; Matsuda, H; Sumiya, H; Noguchi, K; Shimizu, M; Tsuji, S; Kinuya, S; Shuke, N; Yokoyama, K; Seto, H

    2002-04-01

    The purpose of this retrospective study was to assess regional cerebral blood flow in patients after carbon monoxide intoxication by using brain single photon emission computed tomography and statistical parametric mapping. Eight patients with delayed neuropsychiatric sequelae and ten patients with no neuropsychiatric symptoms after carbon monoxide intoxication were studied with brain single photon emission tomography imaging with 99mTc-hexamethyl-propyleneamine oxime. Forty-four control subjects were also studied. We used the adjusted regional cerebral blood flow images in relative flow distribution (normalization of global cerebral blood flow for each subject to 50 ml x 100 g(-1) x min(-1) with proportional scaling) to compare these groups with statistical parametric mapping. Using this technique, significantly decreased regional cerebral blood flow was noted extensively in the bilateral frontal lobes as well as the bilateral insula and a part of the right temporal lobe in the patients with delayed neuropsychiatric sequelae as compared with normal volunteers (P< 0.005). In the patients with no neuropsychiatric symptoms, significantly decreased regional blood flow in the bilateral frontal lobes particularly on the left side was detected. There was a significantly decreased regional cerebral blood flow in the right frontal lobe and insula in the patients with delayed neuropsychiatric sequelae as compared to those with no neuropsychiatric sequelae. It is concluded that statistical parametric mapping is a useful technique for highlighting differences in regional cerebral blood flow in patients following carbon monoxide intoxication as compared with normal volunteers. The selectively reduced blood flow noted in this investigation supports the contention that the decrease following carbon monoxide intoxication may be prolonged and further worsen in the frontal lobe. In addition, the present study may help to clarify the characteristics of the pathophysiological

  1. Mapping of statistical characteristics of topography on Mars with MOLA data

    NASA Astrophysics Data System (ADS)

    Kreslavsky, M. A.; Head, J. W.

    2003-04-01

    Mars Orbiter Laser Altimeter (MOLA) produced a huge set of precise measurements of Mars surface elevation with uniform 0.3 km spacing along tracks. We use this data set to study statistical characteristics of the martian topography at the scale from hundreds meters to tens of kilometers. Here we give a summary of our published and new results on mapping of statistical characteristics of topography for the purposes of geomorphology and understanding of surface formation and alteration processes. The interquartile widths of the differential-slope- or curvature-frequency distributions are used as measures of the surface roughness at a series of scales. The Hurst exponent quantifies the scale dependence of roughness. The normalized median curvature characterizes the prevalence of concave or convex topography. The normalized median differential slope being a measure of the asymmetry of the slope-frequency distribution, characterizes the north - south slope asymmetry. All maps clearly show the latitudinal trend. High-latitude areas (from the polar deposits edges to 60 deg latitude) are characterized by lower subkilometer-scale roughness, higher Hurst exponent and stronger prevalence of concave topography than the equatorial zone (within 30 deg). The transitional zones (from 30 to 60 deg) are characterized by transitional values of roughness and Hurst exponent, by prevalence of convex topography, and by noticeable slope asymmetry: the equator-facing slopes are steeper. The roughness and Hurst exponent also shows obvious correlation with geological units. The maps shows also some anomalous regions related to distribution of specific surficial deposits. For example, convex topography prevails for giant polygons; eastern part of Daedalia Planum has anomalous prevalence of concave topography and strong slope asymmetry; south-eastern part of Arabia Terra has slope asymmetry and prevalence of convex topography; the hematite deposit has an anomalous signature in all maps.

  2. Intermittent Measurement in Robotic Localization and Mapping with FIM Statistical Bounds

    NASA Astrophysics Data System (ADS)

    Ahmad, Hamzah; Namerikawa, Toru

    The focus of study is to review the FIM statistical behavior in each EKF update and determine its potential in providing sufficient information about Robotic Localization and Mapping problem with intermittent measurements. We provide theoretical analysis and prove that the FIM can successfully describe both upper and lower bounds for the state covariance matrix whenever measurement data is not arrived during robot observations. This approach can give a better picture on how information are processed in EKF when measurement data is partially unavailable. Some simulation evaluations are also included to verify our results and consistently demonstrate the expected outcome.

  3. A Comprehensive Statistical Model for Cell Signaling and Protein Activity Inference

    PubMed Central

    Yörük, Erdem; Ochs, Michael F.; Geman, Donald; Younes, Laurent

    2010-01-01

    Protein signaling networks play a central role in transcriptional regulation and the etiology of many diseases. Statistical methods, particularly Bayesian networks, have been widely used to model cell signaling, mostly for model organisms and with focus on uncovering connectivity rather than inferring aberrations. Extensions to mammalian systems have not yielded compelling results, due likely to greatly increased complexity and limited proteomic measurements in vivo. In this study, we propose a comprehensive statistical model that is anchored to a predefined core topology, has a limited complexity due to parameter sharing and uses micorarray data of mRNA transcripts as the only observable components of signaling. Specifically, we account for cell heterogeneity and a multi-level process, representing signaling as a Bayesian network at the cell level, modeling measurements as ensemble averages at the tissue level and incorporating patient-to-patient differences at the population level. Motivated by the goal of identifying individual protein abnormalities as potential therapeutical targets, we applied our method to the RAS-RAF network using a breast cancer study with 118 patients. We demonstrated rigorous statistical inference, established reproducibility through simulations and the ability to recover receptor status from available microarray data. PMID:20855924

  4. The Kullback-Leibler divergence as an estimator of the statistical properties of CMB maps

    SciTech Connect

    Ben-David, Assaf; Jackson, Andrew D.; Liu, Hao E-mail: liuhao@nbi.dk

    2015-06-01

    The identification of unsubtracted foreground residuals in the cosmic microwave background maps on large scales is of crucial importance for the analysis of polarization signals. These residuals add a non-Gaussian contribution to the data. We propose the Kullback-Leibler (KL) divergence as an effective, non-parametric test on the one-point probability distribution function of the data. With motivation in information theory, the KL divergence takes into account the entire range of the distribution and is highly non-local. We demonstrate its use by analyzing the large scales of the Planck 2013 SMICA temperature fluctuation map and find it consistent with the expected distribution at a level of 6%. Comparing the results to those obtained using the more popular Kolmogorov-Smirnov test, we find the two methods to be in general agreement.

  5. Mapping irrigated lands at 250-m scale by merging MODIS data and National Agricultural Statistics

    USGS Publications Warehouse

    Pervez, Md Shahriar; Brown, Jesslyn F.

    2010-01-01

    Accurate geospatial information on the extent of irrigated land improves our understanding of agricultural water use, local land surface processes, conservation or depletion of water resources, and components of the hydrologic budget. We have developed a method in a geospatial modeling framework that assimilates irrigation statistics with remotely sensed parameters describing vegetation growth conditions in areas with agricultural land cover to spatially identify irrigated lands at 250-m cell size across the conterminous United States for 2002. The geospatial model result, known as the Moderate Resolution Imaging Spectroradiometer (MODIS) Irrigated Agriculture Dataset (MIrAD-US), identified irrigated lands with reasonable accuracy in California and semiarid Great Plains states with overall accuracies of 92% and 75% and kappa statistics of 0.75 and 0.51, respectively. A quantitative accuracy assessment of MIrAD-US for the eastern region has not yet been conducted, and qualitative assessment shows that model improvements are needed for the humid eastern regions where the distinction in annual peak NDVI between irrigated and non-irrigated crops is minimal and county sizes are relatively small. This modeling approach enables consistent mapping of irrigated lands based upon USDA irrigation statistics and should lead to better understanding of spatial trends in irrigated lands across the conterminous United States. An improved version of the model with revised datasets is planned and will employ 2007 USDA irrigation statistics.

  6. Simulated performance of an order statistic threshold strategy for detection of narrowband signals

    NASA Technical Reports Server (NTRS)

    Satorius, E.; Brady, R.; Deich, W.; Gulkis, S.; Olsen, E.

    1988-01-01

    The application of order statistics to signal detection is becoming an increasingly active area of research. This is due to the inherent robustness of rank estimators in the presence of large outliers that would significantly degrade more conventional mean-level-based detection systems. A detection strategy is presented in which the threshold estimate is obtained using order statistics. The performance of this algorithm in the presence of simulated interference and broadband noise is evaluated. In this way, the robustness of the proposed strategy in the presence of the interference can be fully assessed as a function of the interference, noise, and detector parameters.

  7. Signal digitizing system and method based on amplitude-to-time optical mapping

    DOEpatents

    Chou, Jason; Bennett, Corey V; Hernandez, Vince

    2015-01-13

    A signal digitizing system and method based on analog-to-time optical mapping, optically maps amplitude information of an analog signal of interest first into wavelength information using an amplitude tunable filter (ATF) to impress spectral changes induced by the amplitude of the analog signal onto a carrier signal, i.e. a train of optical pulses, and next from wavelength information to temporal information using a dispersive element so that temporal information representing the amplitude information is encoded in the time domain in the carrier signal. Optical-to-electrical conversion of the optical pulses into voltage waveforms and subsequently digitizing the voltage waveforms into a digital image enables the temporal information to be resolved and quantized in the time domain. The digital image may them be digital signal processed to digitally reconstruct the analog signal based on the temporal information with high fidelity.

  8. Identification of Statistical Invariance for Anodic Signals of Mk-IV Electrorefiner

    SciTech Connect

    Supathorn Phongikaroon; Tae-Sic Yoo

    2007-09-01

    A statistical invariance technique is proposed for an analysis of anodic signals from the Mk-IV electrorefiner (ER) currently used for treating spent EBR-II fuel. Voltage and applied current signals obtained from the Data Archival Software System (DASS) were used in this study. In general, the plots of these signals from different experimental runs present complex patterns to analyze—the currents were adjusted and shut-off due to limited ampere-hr or cut-off cell voltage; the voltage would increase showing a sign that uranium in the fuel elements had been depleted. Rather than directly analyzing these sets of time-series signals, a simple nonlinear function of these signal sequences and division were observed, which returned resistance series information. The primary idea deriving the methodology presented in this paper is that “anodic resistance time series should show intrinsic kinetic progress of anodic ER process.” A simple histogram-based analysis reveals notable statistical information, which may be invariant under ideal ER operating conditions. For instance, the results suggest that mostly uranium dissolution would be preferentially transferred around 0.00217 - 0.00354 ohm and other minor distribution peaks may possibly represent other transfers of fission species in the system.

  9. Statistical analysis of storm electrical discharges reconstituted from a lightning mapping system, a lightning location system, and an acoustic array

    NASA Astrophysics Data System (ADS)

    Gallin, Louis-Jonardan; Farges, Thomas; Marchiano, Régis; Coulouvrat, François; Defer, Eric; Rison, William; Schulz, Wolfgang; Nuret, Mathieu

    2016-04-01

    In the framework of the European Hydrological Cycle in the Mediterranean Experiment project, a field campaign devoted to the study of electrical activity during storms took place in the south of France in 2012. An acoustic station composed of four microphones and four microbarometers was deployed within the coverage of a Lightning Mapping Array network. On the 26 October 2012, a thunderstorm passed just over the acoustic station. Fifty-six natural thunder events, due to cloud-to-ground and intracloud flashes, were recorded. This paper studies the acoustic reconstruction, in the low frequency range from 1 to 40 Hz, of the recorded flashes and their comparison with detections from electromagnetic networks. Concurrent detections from the European Cooperation for Lightning Detection lightning location system were also used. Some case studies show clearly that acoustic signal from thunder comes from the return stroke but also from the horizontal discharges which occur inside the clouds. The huge amount of observation data leads to a statistical analysis of lightning discharges acoustically recorded. Especially, the distributions of altitudes of reconstructed acoustic detections are explored in detail. The impact of the distance to the source on these distributions is established. The capacity of the acoustic method to describe precisely the lower part of nearby cloud-to-ground discharges, where the Lightning Mapping Array network is not effective, is also highlighted.

  10. Signal Waveform Detection with Statistical Automaton for Internet and Web Service Streaming

    PubMed Central

    Liu, Yiming; Huang, Nai-Lun; Zeng, Fufu; Lin, Fang-Ying

    2014-01-01

    In recent years, many approaches have been suggested for Internet and web streaming detection. In this paper, we propose an approach to signal waveform detection for Internet and web streaming, with novel statistical automatons. The system records network connections over a period of time to form a signal waveform and compute suspicious characteristics of the waveform. Network streaming according to these selected waveform features by our newly designed Aho-Corasick (AC) automatons can be classified. We developed two versions, that is, basic AC and advanced AC-histogram waveform automata, and conducted comprehensive experimentation. The results confirm that our approach is feasible and suitable for deployment. PMID:25032231

  11. Signal waveform detection with statistical automaton for internet and web service streaming.

    PubMed

    Tseng, Kuo-Kun; Ji, Yuzhu; Liu, Yiming; Huang, Nai-Lun; Zeng, Fufu; Lin, Fang-Ying

    2014-01-01

    In recent years, many approaches have been suggested for Internet and web streaming detection. In this paper, we propose an approach to signal waveform detection for Internet and web streaming, with novel statistical automatons. The system records network connections over a period of time to form a signal waveform and compute suspicious characteristics of the waveform. Network streaming according to these selected waveform features by our newly designed Aho-Corasick (AC) automatons can be classified. We developed two versions, that is, basic AC and advanced AC-histogram waveform automata, and conducted comprehensive experimentation. The results confirm that our approach is feasible and suitable for deployment.

  12. Mapping paths: new approaches to dissect eukaryotic signaling circuitry.

    PubMed

    Mutlu, Nebibe; Kumar, Anuj

    2016-01-01

    Eukaryotic cells are precisely "wired" to coordinate changes in external and intracellular signals with corresponding adjustments in the output of complex and often interconnected signaling pathways. These pathways are critical in understanding cellular growth and function, and several experimental trends are emerging with applicability toward more fully describing the composition and topology of eukaryotic signaling networks. In particular, recent studies have implemented CRISPR/Cas-based screens in mouse and human cell lines for genes involved in various cell growth and disease phenotypes. Proteomic methods using mass spectrometry have enabled quantitative and dynamic profiling of protein interactions, revealing previously undiscovered complexes and allele-specific protein interactions. Methods for the single-cell study of protein localization and gene expression have been integrated with computational analyses to provide insight into cell signaling in yeast and metazoans. In this review, we present an overview of exemplary studies using the above approaches, relevant for the analysis of cell signaling and indeed, more broadly, for many modern biological applications.

  13. Mapping paths: new approaches to dissect eukaryotic signaling circuitry

    PubMed Central

    Mutlu, Nebibe; Kumar, Anuj

    2016-01-01

    Eukaryotic cells are precisely “wired” to coordinate changes in external and intracellular signals with corresponding adjustments in the output of complex and often interconnected signaling pathways. These pathways are critical in understanding cellular growth and function, and several experimental trends are emerging with applicability toward more fully describing the composition and topology of eukaryotic signaling networks. In particular, recent studies have implemented CRISPR/Cas-based screens in mouse and human cell lines for genes involved in various cell growth and disease phenotypes. Proteomic methods using mass spectrometry have enabled quantitative and dynamic profiling of protein interactions, revealing previously undiscovered complexes and allele-specific protein interactions. Methods for the single-cell study of protein localization and gene expression have been integrated with computational analyses to provide insight into cell signaling in yeast and metazoans. In this review, we present an overview of exemplary studies using the above approaches, relevant for the analysis of cell signaling and indeed, more broadly, for many modern biological applications. PMID:27540473

  14. Limitations to mapping habitat-use areas in changing landscapes using the Mahalanobis distance statistic

    USGS Publications Warehouse

    Knick, Steven T.; Rotenberry, J.T.

    1998-01-01

    We tested the potential of a GIS mapping technique, using a resource selection model developed for black-tailed jackrabbits (Lepus californicus) and based on the Mahalanobis distance statistic, to track changes in shrubsteppe habitats in southwestern Idaho. If successful, the technique could be used to predict animal use areas, or those undergoing change, in different regions from the same selection function and variables without additional sampling. We determined the multivariate mean vector of 7 GIS variables that described habitats used by jackrabbits. We then ranked the similarity of all cells in the GIS coverage from their Mahalanobis distance to the mean habitat vector. The resulting map accurately depicted areas where we sighted jackrabbits on verification surveys. We then simulated an increase in shrublands (which are important habitats). Contrary to expectation, the new configurations were classified as lower similarity relative to the original mean habitat vector. Because the selection function is based on a unimodal mean, any deviation, even if biologically positive, creates larger Malanobis distances and lower similarity values. We recommend the Mahalanobis distance technique for mapping animal use areas when animals are distributed optimally, the landscape is well-sampled to determine the mean habitat vector, and distributions of the habitat variables does not change.

  15. Localization and quantification of intramuscular damage using statistical parametric mapping and skeletal muscle parcellation

    PubMed Central

    Fouré, Alexandre; Le Troter, Arnaud; Guye, Maxime; Mattei, Jean-Pierre; Bendahan, David; Gondin, Julien

    2015-01-01

    In the present study, we proposed an original and robust methodology which combines the spatial normalization of skeletal muscle images, the statistical parametric mapping (SPM) analysis and the use of a specific parcellation in order to accurately localize and quantify the extent of skeletal muscle damage within the four heads of the quadriceps femoris. T2 maps of thigh muscles were characterized before, two (D2) and four (D4) days after 40 maximal isometric electrically-evoked contractions in 25 healthy young males. On the basis of SPM analysis of coregistrated T2 maps, the alterations were similarly detected at D2 and D4 in the superficial and distal regions of the vastus medialis (VM) whereas the proportion of altered muscle was higher in deep muscle regions of the vastus lateralis at D4 (deep: 35 ± 25%, superficial: 23 ± 15%) as compared to D2 (deep: 18 ± 13%, superficial: 17 ± 13%). The present methodology used for the first time on skeletal muscle would be of utmost interest to detect subtle intramuscular alterations not only for the diagnosis of muscular diseases but also for assessing the efficacy of potential therapeutic interventions and clinical treatment strategies. PMID:26689827

  16. Mapping vegetation communities using statistical data fusion in the Ozark National Scenic Riverways, Missouri, USA

    USGS Publications Warehouse

    Chastain, R.A.; Struckhoff, M.A.; He, H.S.; Larsen, D.R.

    2008-01-01

    A vegetation community map was produced for the Ozark National Scenic Riverways consistent with the association level of the National Vegetation Classification System. Vegetation communities were differentiated using a large array of variables derived from remote sensing and topographic data, which were fused into independent mathematical functions using a discriminant analysis classification approach. Remote sensing data provided variables that discriminated vegetation communities based on differences in color, spectral reflectance, greenness, brightness, and texture. Topographic data facilitated differentiation of vegetation communities based on indirect gradients (e.g., landform position, slope, aspect), which relate to variations in resource and disturbance gradients. Variables derived from these data sources represent both actual and potential vegetation community patterns on the landscape. A hybrid combination of statistical and photointerpretation methods was used to obtain an overall accuracy of 63 percent for a map with 49 vegetation community and land-cover classes, and 78 percent for a 33-class map of the study area. ?? 2008 American Society for Photogrammetry and Remote Sensing.

  17. Statistical aspect of trait mapping using a dense set of markers: A partial review

    SciTech Connect

    Dupuis, J.

    1996-12-31

    This paper presents a review of statistical methods used to locate trait loci using maps of markers spanning the whole genome. Such maps are becoming readily available and can be especially useful in mapping traits that are non Mendelian. Genome-wide search for a trait locus is often called a {open_quotes}global search{close_quotes}. Global search methods include, but are not restricted to, identifying disease susceptibility genes using affected relative pairs, finding quantitative trait loci in experimental organisms and locating quantitative trait loci in humans. For human linkage, we concentrate on methods using pairs of affected relatives rather than pedigree analysis. We begin in the next section with a review of work on the use of affected pairs of relatives to identify gene loci that increase susceptibility to a particular disease. We first review Risch`s 1990 series of papers. Risch`s method can be used to search the entire genome for such susceptibility genes. Using Risch`s idea Elston explored the issue of how many pairs and markers are necessary to reach a certain probability of detecting a locus if there exists one. He proposed a more economical two stage design that uses few markers at the first stage but adds markers around the {open_quotes}promising{close_quotes} area of the genome at the second stage. However, Risch and Elston do not use multipoint linkage analysis, which takes into account all markers at once (rather than one at a time) in the calculation of the test statistic. Such multipoint methods for affected relatives have been developed by Feingold and Feingold et al. The last authors` multipoint method is based on a continuous specification of identity by descent between the affected relatives but can also be used for a set of linked markers spanning the genome. A brief description of their method and treatment of more complex issues such as combining relative pairs is included. 29 refs., 4 tabs.

  18. Using statistical distances to detect changes in the normal behavior of ECG-Holter signals

    NASA Astrophysics Data System (ADS)

    Bastos de Figueiredo, Julio C.; Furuie, Sergio S.

    2001-05-01

    One of the main problems in the study of complex systems is to define a good metric that can distinguish between different dynamical behaviors in a nonlinear system. In this work we describe a method to detect different types of behaviors in a long term ECG-Holter using short portions of the Holter signal. This method is based on the calculation of the statistical distance between two distributions in a phase-space of a dynamical system. A short portion of an ECG-Holter signal with normal behavior is used to reconstruct the trajectory of an attractor in low dimensional phase-space. The points in this trajectory are interpreted as statistical distributions in the phase-space and assumed to represent the normal dynamical behavior of the ECG recording in this space. A fast algorithm is then used to compute the statistical distance between this attractor and all other attractors that are built using a sliding temporal window over the signal. For normal cases the distance stayed almost constant and below a threshold. For cases with abnormal transients, on the abnormal portion of ECG, the distance increased consistently with morphological changes.

  19. Audio analysis of statistically instantaneous signals with mixed Gaussian probability distributions

    NASA Astrophysics Data System (ADS)

    Naik, Ganesh R.; Wang, Wenwu

    2012-10-01

    In this article, a novel method is proposed to measure the separation qualities of statistically instantaneous audio signals with mixed Gaussian probability distributions. This study evaluates the impact of the Probability Distribution Function (PDF) of the mixed signals on the outcomes of both sub- and super-Gaussian distributions. Different Gaussian measures are evaluated by using various spectral-distortion measures. It aims to compare the different audio mixtures from both super-Gaussian and sub-Gaussian perspectives. Extensive computer simulation confirms that the separated sources always have super-Gaussian characteristics irrespective of the PDF of the signals or mixtures. The result based on the objective measures demonstrates the effectiveness of source separation in improving the quality of the separated audio sources.

  20. Higher-order-statistics-based radial basis function networks for signal enhancement.

    PubMed

    Lin, Bor-Shyh; Lin, Bor-Shing; Chong, Fok-Ching; Lai, Feipei

    2007-05-01

    In this paper, a higher-order-statistics (HOS)-based radial basis function (RBF) network for signal enhancement is introduced. In the proposed scheme, higher order cumulants of the reference signal were used as the input of HOS-based RBF. An HOS-based supervised learning algorithm, with mean square error obtained from higher order cumulants of the desired input and the system output as the learning criterion, was used to adapt weights. The motivation is that the HOS can effectively suppress Gaussian and symmetrically distributed non-Gaussian noise. The influence of a Gaussian noise on the input of HOS-based RBF and the HOS-based learning algorithm can be mitigated. Simulated results indicate that HOS-based RBF can provide better performance for signal enhancement under different noise levels, and its performance is insensitive to the selection of learning rates. Moreover, the efficiency of HOS-based RBF under the nonstationary Gaussian noise is stable.

  1. Statistics

    Cancer.gov

    Links to sources of cancer-related statistics, including the Surveillance, Epidemiology and End Results (SEER) Program, SEER-Medicare datasets, cancer survivor prevalence data, and the Cancer Trends Progress Report.

  2. A topographic instructive signal guides the adjustment of the auditory space map in the optic tectum.

    PubMed

    Hyde, P S; Knudsen, E I

    2001-11-01

    Maps of auditory space in the midbrain of the barn owl (Tyto alba) are calibrated by visual experience. When owls are raised wearing prismatic spectacles that displace the visual field in azimuth, the auditory receptive fields of neurons in the optic tectum shift to compensate for the optical displacement of the visual field. This shift results primarily from a shift in the tuning of tectal neurons for interaural time difference. The visually based instructive signal that guides this plasticity could be based on a topographic, point-by-point comparison between auditory and visual space maps or on a foveation-dependent visual assessment of the accuracy of auditory orienting responses. To distinguish between these two possibilities, we subjected owls to optical conditions that differed in the center of gaze and the visual periphery. A topographic signal would cause the portions of the space map representing the central and peripheral regions of visual space to adjust differently, according to the optical conditions that exist in each region. In contrast, a foveation-based signal would cause both portions of the map to adjust similarly, according to the optical conditions that exist at the center of gaze. In six of seven experiments, adaptive changes were as predicted by a topographic instructive signal. Although the results do not rule out the possible contribution of a foveation-based signal, they demonstrate that a topographic instructive signal is, indeed, involved in the calibration of the auditory space map in the barn owl optic tectum. PMID:11606646

  3. Photon statistics of pulse-pumped four-wave mixing in fiber with weak signal injection

    NASA Astrophysics Data System (ADS)

    Nan-Nan, Liu; Yu-Hong, Liu; Jia-Min, Li; Xiao-Ying, Li

    2016-07-01

    We study the photon statistics of pulse-pumped four-wave mixing in fibers with weak coherent signal injection by measuring the intensity correlation functions of individual signal and idler fields. The experimental results show that the intensity correlation function of individual signal (idler) field decreases with the intensity of signal injection. After applying narrow band filter in signal (idler) band, the value of decreases from 1.9 ± 0.02 (1.9 ± 0.02) to 1.03 ± 0.02 (1.05 ± 0.02) when the intensity of signal injection varies from 0 to 120 photons/pulse. The results indicate that the photon statistics changes from Bose-Einstein distribution to Poisson distribution. We calculate the intensity correlation functions by using the multi-mode theory of four-wave mixing in fibers. The theoretical curves well fit the experimental results. Our investigation will be useful for mitigating the crosstalk between quantum and classical channels in a dense wavelength division multiplexing network. Project supported by the National Natural Science Foundation of China (Grant No. 11527808), the State Key Development Program for Basic Research of China (Grant No. 2014CB340103), the Specialized Research Fund for the Doctoral Program of Higher Education of China (Grant No. 20120032110055), the Natural Science Foundation of Tianjin, China (Grant No. 14JCQNJC02300), the Program for Changjiang Scholars and Innovative Research Team in University, China, and the Program of Introducing Talents of Discipline to Universities, China (Grant No. B07014).

  4. Photon statistics of pulse-pumped four-wave mixing in fiber with weak signal injection

    NASA Astrophysics Data System (ADS)

    Nan-Nan, Liu; Yu-Hong, Liu; Jia-Min, Li; Xiao-Ying, Li

    2016-07-01

    We study the photon statistics of pulse-pumped four-wave mixing in fibers with weak coherent signal injection by measuring the intensity correlation functions of individual signal and idler fields. The experimental results show that the intensity correlation function of individual signal (idler) field decreases with the intensity of signal injection. After applying narrow band filter in signal (idler) band, the value of decreases from 1.9 ± 0.02 (1.9 ± 0.02) to 1.03 ± 0.02 (1.05 ± 0.02) when the intensity of signal injection varies from 0 to 120 photons/pulse. The results indicate that the photon statistics changes from Bose–Einstein distribution to Poisson distribution. We calculate the intensity correlation functions by using the multi-mode theory of four-wave mixing in fibers. The theoretical curves well fit the experimental results. Our investigation will be useful for mitigating the crosstalk between quantum and classical channels in a dense wavelength division multiplexing network. Project supported by the National Natural Science Foundation of China (Grant No. 11527808), the State Key Development Program for Basic Research of China (Grant No. 2014CB340103), the Specialized Research Fund for the Doctoral Program of Higher Education of China (Grant No. 20120032110055), the Natural Science Foundation of Tianjin, China (Grant No. 14JCQNJC02300), the Program for Changjiang Scholars and Innovative Research Team in University, China, and the Program of Introducing Talents of Discipline to Universities, China (Grant No. B07014).

  5. AlzPathway, an Updated Map of Curated Signaling Pathways: Towards Deciphering Alzheimer's Disease Pathogenesis.

    PubMed

    Ogishima, Soichi; Mizuno, Satoshi; Kikuchi, Masataka; Miyashita, Akinori; Kuwano, Ryozo; Tanaka, Hiroshi; Nakaya, Jun

    2016-01-01

    Alzheimer's disease (AD) is a complex neurodegenerative disorder in which loss of neurons and synaptic function causes dementia in the elderly. To clarify AD pathogenesis and develop drugs for AD, thousands of studies have elucidated signaling pathways involved. However, knowledge of AD signaling pathways has not been compiled as a pathway map. In this chapter, we introduce the manual construction of a pathway map in AD which we call "AlzPathway", that comprehensively catalogs signaling pathways in the field of AD. We have collected and manually curated over 100 review articles related to AD, and have built the AD pathway map. AlzPathway is currently composed of thousands of molecules and reactions in neurons, brain blood barrier, presynaptic, postsynaptic, astrocyte, and microglial cells, with their cellular localizations. AlzPathway provides a systems-biology platform of comprehensive AD signaling and related pathways which is expected to contribute to clarification of AD pathogenesis and AD drug development.

  6. Mapping toll-like receptor signaling pathway genes of Zhikong scallop ( Chlamys farreri) with FISH

    NASA Astrophysics Data System (ADS)

    Zhao, Bosong; Zhao, Liang; Liao, Huan; Cheng, Jie; Lian, Shanshan; Li, Xuan; Huang, Xiaoting; Bao, Zhenmin

    2015-12-01

    Toll-like receptor (TLR) signaling pathway plays a pivotal role in the innate immune system. Studies on TLR signaling pathway genes in Zhikong scallop ( Chlamys farreri) have mainly focused on sequence analysis and expression profiling, no research has been carried out on their localization. The chromosomal position of TLR signaling pathway genes can be valuable for assemblying scallop genome and analysizing gene regulatory networks. In the present study, five key TLR signaling pathway genes ( CfTLR, CfMyd88, CfTRAF6, CfNFκB, and CfIκB) containing bacterial artificial chromosomes (BACs) were isolated and physically mapped through fluorescence in situ hybridization on five non-homologous chromosome pairs, showing a similar distribution to another five model species. The isolation and mapping of these key immune genes of C. farreri will aid to the research on innate immunity, assignment of interested genes to chromosomes, and integration of physical, linkage and cytogenetic maps of this species.

  7. β-Arrestin drives MAP kinase signalling from clathrin-coated structures after GPCR dissociation.

    PubMed

    Eichel, K; Jullié, D; von Zastrow, M

    2016-03-01

    β-Arrestins critically regulate G-protein-coupled receptor (GPCR) signalling, not only 'arresting' the G protein signal but also modulating endocytosis and initiating a discrete G-protein-independent signal through MAP kinase. Despite enormous recent progress towards understanding biophysical aspects of arrestin function, arrestin cell biology remains relatively poorly understood. Two key tenets underlie the prevailing current view: β-arrestin accumulates in clathrin-coated structures (CCSs) exclusively in physical complex with its activating GPCR, and MAP kinase activation requires endocytosis of formed GPCR-β-arrestin complexes. We show here, using β1-adrenergic receptors, that β-arrestin-2 (arrestin 3) accumulates robustly in CCSs after dissociating from its activating GPCR and transduces the MAP kinase signal from CCSs. Moreover, inhibiting subsequent endocytosis of CCSs enhances the clathrin- and β-arrestin-dependent MAP kinase signal. These results demonstrate β-arrestin 'activation at a distance', after dissociating from its activating GPCR, and signalling from CCSs. We propose a β-arrestin signalling cycle that is catalytically activated by the GPCR and energetically coupled to the endocytic machinery.

  8. β-arrestin drives MAP kinase signaling from clathrin-coated structures after GPCR dissociation

    PubMed Central

    Eichel, K.; Jullié, D.

    2016-01-01

    β-arrestins critically regulate G protein-coupled receptor (GPCR) signaling, not only 'arresting' the G protein signal but also modulating endocytosis and initiating a discrete G protein-independent signal via MAP kinase1–3. Despite enormous recent progress toward understanding biophysical aspects of arrestin function4,5, its cell biology remains relatively poorly understood. Two key tenets underlie the present dogma: (1) β-arrestin accumulates in clathrin-coated structures (CCSs) exclusively in physical complex with its activating GPCR, and (2) MAP kinase activation requires endocytosis of formed GPCR - β-arrestin complexes6–9. We show here, using β1-adrenergic receptors, that β-arrestin-2 (Arrestin 3) accumulates robustly in CCSs after dissociating from its activating GPCR and transduces the MAP kinase signal from CCSs. Moreover, inhibiting subsequent endocytosis of CCSs enhances the clathrin and β-arrestin -dependent MAP kinase signal. These results demonstrate β-arrestin 'activation at a distance', after dissociating from its activating GPCR, and signaling from CCSs. We propose a β-arrestin signaling cycle that is catalytically activated by the GPCR and energetically coupled to the endocytic machinery. PMID:26829388

  9. β-Arrestin drives MAP kinase signalling from clathrin-coated structures after GPCR dissociation.

    PubMed

    Eichel, K; Jullié, D; von Zastrow, M

    2016-03-01

    β-Arrestins critically regulate G-protein-coupled receptor (GPCR) signalling, not only 'arresting' the G protein signal but also modulating endocytosis and initiating a discrete G-protein-independent signal through MAP kinase. Despite enormous recent progress towards understanding biophysical aspects of arrestin function, arrestin cell biology remains relatively poorly understood. Two key tenets underlie the prevailing current view: β-arrestin accumulates in clathrin-coated structures (CCSs) exclusively in physical complex with its activating GPCR, and MAP kinase activation requires endocytosis of formed GPCR-β-arrestin complexes. We show here, using β1-adrenergic receptors, that β-arrestin-2 (arrestin 3) accumulates robustly in CCSs after dissociating from its activating GPCR and transduces the MAP kinase signal from CCSs. Moreover, inhibiting subsequent endocytosis of CCSs enhances the clathrin- and β-arrestin-dependent MAP kinase signal. These results demonstrate β-arrestin 'activation at a distance', after dissociating from its activating GPCR, and signalling from CCSs. We propose a β-arrestin signalling cycle that is catalytically activated by the GPCR and energetically coupled to the endocytic machinery. PMID:26829388

  10. Systematic Mapping and Statistical Analyses of Valley Landform and Vegetation Asymmetries Across Hydroclimatic Gradients

    NASA Astrophysics Data System (ADS)

    Poulos, M. J.; Pierce, J. L.; McNamara, J. P.; Flores, A. N.; Benner, S. G.

    2015-12-01

    Terrain aspect alters the spatial distribution of insolation across topography, driving eco-pedo-hydro-geomorphic feedbacks that can alter landform evolution and result in valley asymmetries for a suite of land surface characteristics (e.g. slope length and steepness, vegetation, soil properties, and drainage development). Asymmetric valleys serve as natural laboratories for studying how landscapes respond to climate perturbation. In the semi-arid montane granodioritic terrain of the Idaho batholith, Northern Rocky Mountains, USA, prior works indicate that reduced insolation on northern (pole-facing) aspects prolongs snow pack persistence, and is associated with thicker, finer-grained soils, that retain more water, prolong the growing season, support coniferous forest rather than sagebrush steppe ecosystems, stabilize slopes at steeper angles, and produce sparser drainage networks. We hypothesize that the primary drivers of valley asymmetry development are changes in the pedon-scale water-balance that coalesce to alter catchment-scale runoff and drainage development, and ultimately cause the divide between north and south-facing land surfaces to migrate northward. We explore this conceptual framework by coupling land surface analyses with statistical modeling to assess relationships and the relative importance of land surface characteristics. Throughout the Idaho batholith, we systematically mapped and tabulated various statistical measures of landforms, land cover, and hydroclimate within discrete valley segments (n=~10,000). We developed a random forest based statistical model to predict valley slope asymmetry based upon numerous measures (n>300) of landscape asymmetries. Preliminary results suggest that drainages are tightly coupled with hillslopes throughout the region, with drainage-network slope being one of the strongest predictors of land-surface-averaged slope asymmetry. When slope-related statistics are excluded, due to possible autocorrelation, valley

  11. Mapping character types onto space: the urban-rural distinction in early statistical writings.

    PubMed

    Bayatrizi, Zohreh

    2011-01-01

    This article investigates the construction of urban/rural binary distinctions in 18th- and 19th-century social scientific literature, and in particular in the writings of the statistical societies in England. The 18th-century writers were primarily concerned with the spread of luxury, vice, and effeminacy among the upper social strata in large cities. Later on, statisticians began to focus on moral hazards among the urban working poor. These writings are significant in several respects: they contributed to the spatial mapping of moral character, played a role in the development of quantitative social scientific techniques, and foreshadowed later sociological debates over the nature and consequences of social evolution from simpler to more complex societies.

  12. Mapping permeability in low-resolution micro-CT images: A multiscale statistical approach

    NASA Astrophysics Data System (ADS)

    Botha, Pieter W. S. K.; Sheppard, Adrian P.

    2016-06-01

    We investigate the possibility of predicting permeability in low-resolution X-ray microcomputed tomography (µCT). Lower-resolution whole core images give greater sample coverage and are therefore more representative of heterogeneous systems; however, the lower resolution causes connecting pore throats to be represented by intermediate gray scale values and limits information on pore system geometry, rendering such images inadequate for direct permeability simulation. We present an imaging and computation workflow aimed at predicting absolute permeability for sample volumes that are too large to allow direct computation. The workflow involves computing permeability from high-resolution µCT images, along with a series of rock characteristics (notably open pore fraction, pore size, and formation factor) from spatially registered low-resolution images. Multiple linear regression models correlating permeability to rock characteristics provide a means of predicting and mapping permeability variations in larger scale low-resolution images. Results show excellent agreement between permeability predictions made from 16 and 64 µm/voxel images of 25 mm diameter 80 mm tall core samples of heterogeneous sandstone for which 5 µm/voxel resolution is required to compute permeability directly. The statistical model used at the lowest resolution of 64 µm/voxel (similar to typical whole core image resolutions) includes open pore fraction and formation factor as predictor characteristics. Although binarized images at this resolution do not completely capture the pore system, we infer that these characteristics implicitly contain information about the critical fluid flow pathways. Three-dimensional permeability mapping in larger-scale lower resolution images by means of statistical predictions provides input data for subsequent permeability upscaling and the computation of effective permeability at the core scale.

  13. Advances in statistical methods to map quantitative trait loci in outbred populations.

    PubMed

    Hoeschele, I; Uimari, P; Grignola, F E; Zhang, Q; Gage, K M

    1997-11-01

    Statistical methods to map quantitative trait loci (QTL) in outbred populations are reviewed, extensions and applications to human and plant genetic data are indicated, and areas for further research are identified. Simple and computationally inexpensive methods include (multiple) linear regression of phenotype on marker genotypes and regression of squared phenotypic differences among relative pairs on estimated proportions of identity-by-descent at a locus. These methods are less suited for genetic parameter estimation in outbred populations but allow the determination of test statistic distributions via simulation or data permutation; however, further inferences including confidence intervals of QTL location require the use of Monte Carlo or bootstrap sampling techniques. A method which is intermediate in computational requirements is residual maximum likelihood (REML) with a covariance matrix of random QTL effects conditional on information from multiple linked markers. Testing for the number of QTLs on a chromosome is difficult in a classical framework. The computationally most demanding methods are maximum likelihood and Bayesian analysis, which take account of the distribution of multilocus marker-QTL genotypes on a pedigree and permit investigators to fit different models of variation at the QTL. The Bayesian analysis includes the number of QTLs on a chromosome as an unknown.

  14. An integrated user-friendly ArcMAP tool for bivariate statistical modeling in geoscience applications

    NASA Astrophysics Data System (ADS)

    Jebur, M. N.; Pradhan, B.; Shafri, H. Z. M.; Yusof, Z.; Tehrany, M. S.

    2014-10-01

    Modeling and classification difficulties are fundamental issues in natural hazard assessment. A geographic information system (GIS) is a domain that requires users to use various tools to perform different types of spatial modeling. Bivariate statistical analysis (BSA) assists in hazard modeling. To perform this analysis, several calculations are required and the user has to transfer data from one format to another. Most researchers perform these calculations manually by using Microsoft Excel or other programs. This process is time consuming and carries a degree of uncertainty. The lack of proper tools to implement BSA in a GIS environment prompted this study. In this paper, a user-friendly tool, BSM (bivariate statistical modeler), for BSA technique is proposed. Three popular BSA techniques such as frequency ratio, weights-of-evidence, and evidential belief function models are applied in the newly proposed ArcMAP tool. This tool is programmed in Python and is created by a simple graphical user interface, which facilitates the improvement of model performance. The proposed tool implements BSA automatically, thus allowing numerous variables to be examined. To validate the capability and accuracy of this program, a pilot test area in Malaysia is selected and all three models are tested by using the proposed program. Area under curve is used to measure the success rate and prediction rate. Results demonstrate that the proposed program executes BSA with reasonable accuracy. The proposed BSA tool can be used in numerous applications, such as natural hazard, mineral potential, hydrological, and other engineering and environmental applications.

  15. Signal detection using the radial basis function coupled map lattice.

    PubMed

    Leung, H; Hennessey, G; Drosopoulos, A

    2000-01-01

    Conventional detection methods used in current marine radar systems do not perform efficiently in detecting small targets embedded in a clutter environment. Based on a recent observation that sea clutter, radar echoes from a sea surface, is chaotic rather than random, we propose using a spatial temporal predictor to reconstruct the chaotic dynamic of sea clutter because electromagnetic wave scattering is a spatial temporal phenomenon which is physically modeled by partial differential equations. The spatial temporal predictor used here is called radial basis function coupled map lattice (RBF-CML) which uses a linear combiner to fuse either measurements in different spatial domains for an RBF prediction or predictions from several RBF nets operated on different spatial regions. Using real-life radar data, it is shown that the RBF-CML is an effective method to reconstruct the sea clutter dynamic. The RBF-CML predictor is then applied to detect small targets in sea clutter using the constant false alarm rate (CFAR) principle. The spatial temporal approach is shown, both theoretically and experimentally, to be superior to a conventional CFAR detector.

  16. Comparison of Signals from Gravitational Wave Detectors with Instantaneous Time-Frequency Maps

    NASA Technical Reports Server (NTRS)

    Stroeer, A.; Blackburn, L.; Camp, J.

    2011-01-01

    Gravitational wave astronomy relies on the use of multiple detectors, so that coincident detections may distinguish real signals from instrumental artifacts, and also so that relative timing of signals can provide the sky position of sources. We show that the comparison of instantaneous time-frequency and time-amplitude maps provided by the Hilbert-Huang Transform (HHT) can be used effectively for relative signal timing of common signals, to discriminate between the case of identical coincident signals and random noise coincidences and to provide a classification of signals based on their time-frequency trajectories. The comparison is done with a X(sup 2) goodness-offit method which includes contributions from both the instantaneous amplitude and frequency components of the HHT to match two signals in the time domain. This approach naturally allows the analysis of waveforms with strong frequency modulation.

  17. Comparison of signals from gravitational wave detectors with instantaneous time-frequency maps

    NASA Astrophysics Data System (ADS)

    Stroeer, A.; Blackburn, L.; Camp, J.

    2011-08-01

    Gravitational wave astronomy relies on the use of multiple detectors, so that coincident detections may distinguish real signals from instrumental artifacts, and also so that relative timing of signals can provide the sky position of sources. We show that the comparison of instantaneous time-frequency and time-amplitude maps provided by the Hilbert-Huang Transform (HHT) can be used effectively for relative signal timing of common signals, to discriminate between the case of identical coincident signals and random noise coincidences and to provide a classification of signals based on their time-frequency trajectories. The comparison is done with a χ2 goodness-of-fit method which includes contributions from both the instantaneous amplitude and frequency components of the HHT to match two signals in the time domain. This approach naturally allows the analysis of waveforms with strong frequency modulation.

  18. Landslide Mapping and Modeling Using Remote Sensing, GIS and Statistical Analysis of District Muzaffarabad, Pakistan

    NASA Astrophysics Data System (ADS)

    Khalid, Nimrah; Mushtaq, Saman

    2016-07-01

    Occurrence factors of Landslide hazard can be natural such as high slopes, geological conditions and lineaments, faults, rain, and river cutting. Man-made factors such as road cuttings, deforestation or development can also contribute to the landsliding. The focus of this study was to model those landslides susceptible prone to hazard areas which in turn can help for the development, urbanization and for setting up rules or regulations to save nature and environment of the area. The focal of the current research work was the Earthquake of October, 2005 also known as Kashmir Earthquake, the epicenter location of the earthquake 34°29'35″N 73°37'44″E at height of ~2000 from mean sea level and ~20 Km North-East from Muzaffarabad city, Azad Jammu & Kashmir, at the scale of 1:50000 Geological map of 43-F/11, tehsil Nauseri area. The techniques used in this research is based on theorem of Bayes's bivariat statistic (weight of evidence) which predicts the events geographically and on input layers and the relationship of event. A relationship between event of landslide and factors was studied and analyzed using this method. Subsequently a prediction of the occurrence of the spatial location of the landslide event was established successfully. The relationship of distribution of landslide and factors layers was calculated using the statistical methods which enabled to predict the landslides zones in different areas. The methodology applied proved that the success rate was 80% landslide occurred in 18% area and prediction rate was 70% of landslides occurred in 70% of area. The use satellite remote sensing data, and GIS with the integration of statistical method are definitely an effective tool for predicting the future landslide prone areas.

  19. An experimental study of the temporal statistics of radio signals scattered by rain

    NASA Technical Reports Server (NTRS)

    Hubbard, R. W.; Hull, J. A.; Rice, P. L.; Wells, P. I.

    1973-01-01

    A fixed-beam bistatic CW experiment designed to measure the temporal statistics of the volume reflectivity produced by hydrometeors at several selected altitudes, scattering angles, and at two frequencies (3.6 and 7.8 GHz) is described. Surface rain gauge data, local meteorological data, surveillance S-band radar, and great-circle path propagation measurements were also made to describe the general weather and propagation conditions and to distinguish precipitation scatter signals from those caused by ducting and other nonhydrometeor scatter mechanisms. The data analysis procedures were designed to provide an assessment of a one-year sample of data with a time resolution of one minute. The cumulative distributions of the bistatic signals for all of the rainy minutes during this period are presented for the several path geometries.

  20. Time-REferenced data Kriging (TREK): mapping hydrological statistics given their time of reference

    NASA Astrophysics Data System (ADS)

    Porcheron, Delphine; Leblois, Etienne; Sauquet, Eric

    2016-04-01

    A major issue in water sciences is to predict runoff parameters at ungauged sites. Estimates can be obtained by various methods. Among them, geostatistical approaches provide interpolation methods that consequently use explicit assumptions on the variable of interest. Geostatistical techniques have been applied to precipitation and temperature fields and later extended to estimate runoff features considered as basin-support variates along the river network (e.g. Gottschalk, 1993; Sauquet et al., 2000; Skoien et al., 2006; Gottschalk et al., 2011). To obtain robust estimations, the first step is to collect a relevant dataset. Sauquet et al. (2000) and Sauquet (2006) suggest including a large number of catchments with long and common observation periods to ensure both reliability and temporal consistency in runoff estimates. However most observation networks evolve with time. Several choices are thus possible to define an optimal reference period maximizing either spatial or temporal overlap. However, the constraints usually lead to discard a significant number of stations. Time-REferenced data Kriging method (TREK) has been developed to overcome this issue. Here is proposed a method of geostatistical estimation considering the temporal support over which a hydrological statistic has been estimated. This allows attenuating the loss of data previously caused by the application of a strict reference period. The time reference remains for the targeted map itself. The weights depend on the observation period of the data included in the dataset and how near this is to the target period. In this presentation, the concepts of TREK will be introduced and thereafter illustrated to map mean annual runoff in France. References Gottschalk, L., 1993, Correlation and covariance of runoff. Stochastic Hydrology and Hydraulics 7(2), 85-101. Sauquet, E., Gottschalk, L. and Leblois, E., 2000, Mapping average annual runoff: a hierarchical approach applying a stochastic interpolation

  1. Automated Coronal Seismology: Curvelet Characterization of Probability Maps of Image Data with Oscillatory Signal

    NASA Astrophysics Data System (ADS)

    Young, C.; Ireland, J.

    2010-12-01

    Automated coronal seismology will require measurements of the structure that supports an oscillatory signal; for example, a measurement of the loop length of a transversely oscillating loop can be used to estimate the coronal magnetic field (Nakariakov& Ofman 2001). One of the results from the recently published Bayesian probability based automated oscillation detection algorithm (Ireland et al., 2010) is a probability map. This is an image of the probability that each pixel from a set of images contains an oscillatory signal. A map from a significant detection contains one or more clusters of high probability pixels dispersed amongst mostly pixels of low probability. These low probability pixels amount to noise while the clusters of high probability are the desired signal. A visual inspection of the probability maps that contain significant signal reveal that the clusters of pixels contain structure that corresponds to physical regions in the original images i.e. oscillating loops. A necessary step for using these oscillation probability maps is to extract and characterize these high probability regions. A natural choice for an appropriate representation of these structures especially given their corresponds to real extended features such as loops is the curvelet transform (Candes and Donoho, 1999 and Candes et al., 2005). In this work we present a preliminary analysis of these probability maps using curvelets to isolate and characterize regions of high probability. The suitability of this technique for the pipeline processing of Solar Dynamics Observatory data is also discussed.

  2. Flexible generation of optical nonuniform bit-mapping signal based on InP transmitter module.

    PubMed

    Liu, Bo; Zhang, Lijia; Xin, Xiangjun; Liu, Lei

    2014-01-15

    Flexible generation of an optical nonuniform bit-mapping signal based on an InP transmitter module is demonstrated. It can realize flexible bit mapping through the photonic modulation method, which can break the limitations of an electrical digital-to-analog convertor and field-programmable gate array. This module has potential to easily increase the signal rate or refine the granularity without electronics, which indicates it may be a future application to replace the traditional transmitter. The feasibility and performance of the proposed scheme are demonstrated in the experiment.

  3. MAP1S Protein Regulates the Phagocytosis of Bacteria and Toll-like Receptor (TLR) Signaling.

    PubMed

    Shi, Ming; Zhang, Yifan; Liu, Leyuan; Zhang, Tingting; Han, Fang; Cleveland, Joseph; Wang, Fen; McKeehan, Wallace L; Li, Yu; Zhang, Dekai

    2016-01-15

    Phagocytosis is a critical cellular process for innate immune defense against microbial infection. The regulation of phagocytosis process is complex and has not been well defined. An intracellular molecule might regulate cell surface-initiated phagocytosis, but the underlying molecular mechanism is poorly understood (1). In this study, we found that microtubule-associated protein 1S (MAP1S), a protein identified recently that is involved in autophagy (2), is expressed primarily in macrophages. MAP1S-deficient macrophages are impaired in the phagocytosis of bacteria. Furthermore, we demonstrate that MAP1S interacts directly with MyD88, a key adaptor of Toll-like receptors (TLRs), upon TLR activation and affects the TLR signaling pathway. Intriguingly, we also observe that, upon TLR activation, MyD88 participates in autophagy processing in a MAP1S-dependent manner by co-localizing with MAP1 light chain 3 (MAP1-LC3 or LC3). Therefore, we reveal that an intracellular autophagy-related molecule of MAP1S controls bacterial phagocytosis through TLR signaling.

  4. Statistical Analysis of Photopyroelectric Signals using Histogram and Kernel Density Estimation for differentiation of Maize Seeds

    NASA Astrophysics Data System (ADS)

    Rojas-Lima, J. E.; Domínguez-Pacheco, A.; Hernández-Aguilar, C.; Cruz-Orea, A.

    2016-09-01

    Considering the necessity of photothermal alternative approaches for characterizing nonhomogeneous materials like maize seeds, the objective of this research work was to analyze statistically the amplitude variations of photopyroelectric signals, by means of nonparametric techniques such as the histogram and the kernel density estimator, and the probability density function of the amplitude variations of two genotypes of maize seeds with different pigmentations and structural components: crystalline and floury. To determine if the probability density function had a known parametric form, the histogram was determined which did not present a known parametric form, so the kernel density estimator using the Gaussian kernel, with an efficiency of 95 % in density estimation, was used to obtain the probability density function. The results obtained indicated that maize seeds could be differentiated in terms of the statistical values for floury and crystalline seeds such as the mean (93.11, 159.21), variance (1.64× 103, 1.48× 103), and standard deviation (40.54, 38.47) obtained from the amplitude variations of photopyroelectric signals in the case of the histogram approach. For the case of the kernel density estimator, seeds can be differentiated in terms of kernel bandwidth or smoothing constant h of 9.85 and 6.09 for floury and crystalline seeds, respectively.

  5. Quantitative mapping and statistical evaluation of fracture minerals in the granitic bedrock at Forsmark, Sweden

    NASA Astrophysics Data System (ADS)

    Löfgren, Martin; Sidborn, Magnus

    2016-10-01

    This article provides quantitative data on occurrences and amounts of fracture minerals that coat discrete fractures in granitic rock at the Forsmark site in Sweden. The data are useful for retardation modelling of radionuclide and other contaminants, and for groundwater composition calculations. In a unique campaign, 2071 open fractures in groundwater conducting rock have been mapped with respect to chlorite, calcite, and pyrite. In total 767 m of drill core has been studied from very shallow rock down to ~1000 m depth. The occurrences of fracture minerals, their thicknesses, and their fractions of surface coverage have been recorded for up to eight layers for each fracture. Detection limits are, for each layer, 0.1 mm for the thickness and 1 % for the surface coverage, except for pyrite crystals where surface coverages down to 0.01 % are detectable. The abundance of data has permitted statistical treatment, using parametric and non-parametric methods. Parametric fittings have been made to log-normal, truncated log-normal, and beta distributions. Chlorite, calcite, and pyrite were found in 57 %, 52 %, and 10 % of all mapped fractures, respectively. The fracture mineral thickness was 0.1 mm for calcite, 0.2 mm for chlorite, and 2 μm for pyrite, as averaged over the fracture surface area. For 50 % and 99 % of all fractures the total fracture coating thickness was less than 0.1 mm and 1 mm, respectively, which is important for diffusion resistance estimates. Average surface coverages were 18 % for calcite, 38 % for chlorite, and 0.5 % for pyrite. These data may be used for calculating the reaction capacity of flow paths.

  6. Statistical modeling and MAP estimation for body fat quantification with MRI ratio imaging

    NASA Astrophysics Data System (ADS)

    Wong, Wilbur C. K.; Johnson, David H.; Wilson, David L.

    2008-03-01

    We are developing small animal imaging techniques to characterize the kinetics of lipid accumulation/reduction of fat depots in response to genetic/dietary factors associated with obesity and metabolic syndromes. Recently, we developed an MR ratio imaging technique that approximately yields lipid/{lipid + water}. In this work, we develop a statistical model for the ratio distribution that explicitly includes a partial volume (PV) fraction of fat and a mixture of a Rician and multiple Gaussians. Monte Carlo hypothesis testing showed that our model was valid over a wide range of coefficient of variation of the denominator distribution (c.v.: 0-0:20) and correlation coefficient among the numerator and denominator (ρ 0-0.95), which cover the typical values that we found in MRI data sets (c.v.: 0:027-0:063, ρ: 0:50-0:75). Then a maximum a posteriori (MAP) estimate for the fat percentage per voxel is proposed. Using a digital phantom with many PV voxels, we found that ratio values were not linearly related to PV fat content and that our method accurately described the histogram. In addition, the new method estimated the ground truth within +1.6% vs. +43% for an approach using an uncorrected ratio image, when we simply threshold the ratio image. On the six genetically obese rat data sets, the MAP estimate gave total fat volumes of 279 +/- 45mL, values 21% smaller than those from the uncorrected ratio images, principally due to the non-linear PV effect. We conclude that our algorithm can increase the accuracy of fat volume quantification even in regions having many PV voxels, e.g. ectopic fat depots.

  7. Statistical Modeling of Large-Scale Signal Path Loss in Underwater Acoustic Networks

    PubMed Central

    Llor, Jesús; Malumbres, Manuel Perez

    2013-01-01

    In an underwater acoustic channel, the propagation conditions are known to vary in time, causing the deviation of the received signal strength from the nominal value predicted by a deterministic propagation model. To facilitate a large-scale system design in such conditions (e.g., power allocation), we have developed a statistical propagation model in which the transmission loss is treated as a random variable. By applying repetitive computation to the acoustic field, using ray tracing for a set of varying environmental conditions (surface height, wave activity, small node displacements around nominal locations, etc.), an ensemble of transmission losses is compiled and later used to infer the statistical model parameters. A reasonable agreement is found with log-normal distribution, whose mean obeys a log-distance increases, and whose variance appears to be constant for a certain range of inter-node distances in a given deployment location. The statistical model is deemed useful for higher-level system planning, where simulation is needed to assess the performance of candidate network protocols under various resource allocation policies, i.e., to determine the transmit power and bandwidth allocation necessary to achieve a desired level of performance (connectivity, throughput, reliability, etc.). PMID:23396190

  8. SeqGL Identifies Context-Dependent Binding Signals in Genome-Wide Regulatory Element Maps.

    PubMed

    Setty, Manu; Leslie, Christina S

    2015-05-01

    Genome-wide maps of transcription factor (TF) occupancy and regions of open chromatin implicitly contain DNA sequence signals for multiple factors. We present SeqGL, a novel de novo motif discovery algorithm to identify multiple TF sequence signals from ChIP-, DNase-, and ATAC-seq profiles. SeqGL trains a discriminative model using a k-mer feature representation together with group lasso regularization to extract a collection of sequence signals that distinguish peak sequences from flanking regions. Benchmarked on over 100 ChIP-seq experiments, SeqGL outperformed traditional motif discovery tools in discriminative accuracy. Furthermore, SeqGL can be naturally used with multitask learning to identify genomic and cell-type context determinants of TF binding. SeqGL successfully scales to the large multiplicity of sequence signals in DNase- or ATAC-seq maps. In particular, SeqGL was able to identify a number of ChIP-seq validated sequence signals that were not found by traditional motif discovery algorithms. Thus compared to widely used motif discovery algorithms, SeqGL demonstrates both greater discriminative accuracy and higher sensitivity for detecting the DNA sequence signals underlying regulatory element maps. SeqGL is available at http://cbio.mskcc.org/public/Leslie/SeqGL/. PMID:26016777

  9. Statistics and topology of the COBE differential microwave radiometer first-year sky maps

    NASA Technical Reports Server (NTRS)

    Smoot, G. F.; Tenorio, L.; Banday, A. J.; Kogut, A.; Wright, E. L.; Hinshaw, G.; Bennett, C. L.

    1994-01-01

    We use statistical and topological quantities to test the Cosmic Background Explorer (COBE) Differential Microwave Radiometer (DMR) first-year sky maps against the hypothesis that the observed temperature fluctuations reflect Gaussian initial density perturbations with random phases. Recent papers discuss specific quantities as discriminators between Gaussian and non-Gaussian behavior, but the treatment of instrumental noise on the data is largely ignored. The presence of noise in the data biases many statistical quantities in a manner dependent on both the noise properties and the unknown cosmic microwave background temperature field. Appropriate weighting schemes can minimize this effect, but it cannot be completely eliminated. Analytic expressions are presented for these biases, and Monte Carlo simulations are used to assess the best strategy for determining cosmologically interesting information from noisy data. The genus is a robust discriminator that can be used to estimate the power-law quadrupole-normalized amplitude, Q(sub rms-PS), independently of the two-point correlation function. The genus of the DMR data is consistent with Gaussian initial fluctuations with Q(sub rms-PS) = (15.7 +/- 2.2) - (6.6 +/- 0.3)(n - 1) micro-K, where n is the power-law index. Fitting the rms temperature variations at various smoothing angles gives Q(sub rms-PS) = 13.2 +/- 2.5 micro-K and n = 1.7(sup (+0.3) sub (-0.6)). While consistent with Gaussian fluctuations, the first year data are only sufficient to rule out strongly non-Gaussian distributions of fluctuations.

  10. An integrated user-friendly ArcMAP tool for bivariate statistical modelling in geoscience applications

    NASA Astrophysics Data System (ADS)

    Jebur, M. N.; Pradhan, B.; Shafri, H. Z. M.; Yusoff, Z. M.; Tehrany, M. S.

    2015-03-01

    Modelling and classification difficulties are fundamental issues in natural hazard assessment. A geographic information system (GIS) is a domain that requires users to use various tools to perform different types of spatial modelling. Bivariate statistical analysis (BSA) assists in hazard modelling. To perform this analysis, several calculations are required and the user has to transfer data from one format to another. Most researchers perform these calculations manually by using Microsoft Excel or other programs. This process is time-consuming and carries a degree of uncertainty. The lack of proper tools to implement BSA in a GIS environment prompted this study. In this paper, a user-friendly tool, bivariate statistical modeler (BSM), for BSA technique is proposed. Three popular BSA techniques, such as frequency ratio, weight-of-evidence (WoE), and evidential belief function (EBF) models, are applied in the newly proposed ArcMAP tool. This tool is programmed in Python and created by a simple graphical user interface (GUI), which facilitates the improvement of model performance. The proposed tool implements BSA automatically, thus allowing numerous variables to be examined. To validate the capability and accuracy of this program, a pilot test area in Malaysia is selected and all three models are tested by using the proposed program. Area under curve (AUC) is used to measure the success rate and prediction rate. Results demonstrate that the proposed program executes BSA with reasonable accuracy. The proposed BSA tool can be used in numerous applications, such as natural hazard, mineral potential, hydrological, and other engineering and environmental applications.

  11. Quantitative analysis of diffusion tensor imaging (DTI) using statistical parametric mapping (SPM) for brain disorders

    NASA Astrophysics Data System (ADS)

    Lee, Jae-Seung; Im, In-Chul; Kang, Su-Man; Goo, Eun-Hoe; Kwak, Byung-Joon

    2013-07-01

    This study aimed to quantitatively analyze data from diffusion tensor imaging (DTI) using statistical parametric mapping (SPM) in patients with brain disorders and to assess its potential utility for analyzing brain function. DTI was obtained by performing 3.0-T magnetic resonance imaging for patients with Alzheimer's disease (AD) and vascular dementia (VD), and the data were analyzed using Matlab-based SPM software. The two-sample t-test was used for error analysis of the location of the activated pixels. We compared regions of white matter where the fractional anisotropy (FA) values were low and the apparent diffusion coefficients (ADCs) were increased. In the AD group, the FA values were low in the right superior temporal gyrus, right inferior temporal gyrus, right sub-lobar insula, and right occipital lingual gyrus whereas the ADCs were significantly increased in the right inferior frontal gyrus and right middle frontal gyrus. In the VD group, the FA values were low in the right superior temporal gyrus, right inferior temporal gyrus, right limbic cingulate gyrus, and right sub-lobar caudate tail whereas the ADCs were significantly increased in the left lateral globus pallidus and left medial globus pallidus. In conclusion by using DTI and SPM analysis, we were able to not only determine the structural state of the regions affected by brain disorders but also quantitatively analyze and assess brain function.

  12. Moment-to-moment brain signal variability: A next frontier in human brain mapping?

    PubMed Central

    Garrett, Douglas D.; Samanez-Larkin, Gregory R.; MacDonald, Stuart W.S.; Lindenberger, Ulman; McIntosh, Anthony R.; Grady, Cheryl L.

    2013-01-01

    Neuroscientists have long observed that brain activity is naturally variable from moment-to-moment, but neuroimaging research has largely ignored the potential importance of this phenomenon. An emerging research focus on within-person brain signal variability is providing novel insights, and offering highly predictive, complementary, and even orthogonal views of brain function in relation to human life-span development, cognitive performance, and various clinical conditions. As a result, brain signal variability is evolving as a bona fide signal of interest, and should no longer be dismissed as meaningless noise when mapping the human brain. PMID:23458776

  13. Statistics of the epoch of reionization 21-cm signal - I. Power spectrum error-covariance

    NASA Astrophysics Data System (ADS)

    Mondal, Rajesh; Bharadwaj, Somnath; Majumdar, Suman

    2016-02-01

    The non-Gaussian nature of the epoch of reionization (EoR) 21-cm signal has a significant impact on the error variance of its power spectrum P(k). We have used a large ensemble of seminumerical simulations and an analytical model to estimate the effect of this non-Gaussianity on the entire error-covariance matrix {C}ij. Our analytical model shows that {C}ij has contributions from two sources. One is the usual variance for a Gaussian random field which scales inversely of the number of modes that goes into the estimation of P(k). The other is the trispectrum of the signal. Using the simulated 21-cm Signal Ensemble, an ensemble of the Randomized Signal and Ensembles of Gaussian Random Ensembles we have quantified the effect of the trispectrum on the error variance {C}ii. We find that its relative contribution is comparable to or larger than that of the Gaussian term for the k range 0.3 ≤ k ≤ 1.0 Mpc-1, and can be even ˜200 times larger at k ˜ 5 Mpc-1. We also establish that the off-diagonal terms of {C}ij have statistically significant non-zero values which arise purely from the trispectrum. This further signifies that the error in different k modes are not independent. We find a strong correlation between the errors at large k values (≥0.5 Mpc-1), and a weak correlation between the smallest and largest k values. There is also a small anticorrelation between the errors in the smallest and intermediate k values. These results are relevant for the k range that will be probed by the current and upcoming EoR 21-cm experiments.

  14. Statistical signal processing for detection of buried land mines using quadrupole resonance

    NASA Astrophysics Data System (ADS)

    Liu, Feng; Tantum, Stacy L.; Collins, Leslie M.; Carin, Lawrence

    2000-08-01

    Quadrupole resonance (QR) is a technique that discriminates mines from clutter by exploiting unique properties of explosives, rather than the attributes of the mine that exist in many forms of anthropic clutter. After exciting the explosive with a properly designed electromagnetic-induction (EMI) system, one attempts to sense late-time spin echoes, which are characterized by radiation at particular frequencies. It is this narrow-band radiation that indicates the present of explosives, since this effect is not seen in most clutter, both natural and anthropic. However, explosives detection via QR is complicated by several practical issues. First, the late-time radiation is often very weak, particularly for TNT, and therefore the signal- to-noise ratio must be high for extracting the QR response. Further, the frequency at which the radiation occurs is often a strong function of the background environment, and therefore in practice the QR radiation frequency is not known a priori. Also, at frequencies of interest, there is a significant amount of background radiation, which induces radio frequency interference (RFI). In addition, the response properties of the system are sensitive to the height of the sensor above the ground, and the QR sensor effectively becomes 'de-tuned'. Finally, present QR systems cannot detect the explosive in metal-cased mines, thus the system and associated signal processing must be extended to also operate as a metal detector. Previously, we have shown that adaptive noise cancellation techniques, in particular, the least-mean-square algorithm, provide an effective means of RFI mitigation and can dramatically improve QR detection. In this paper we discuss several signal processing tools we have developed to further enhance the utility of QR explosives detection. In particular, with regard to the uncertainties concerning the background environment and sensor height, we explore statistical signal processing strategies to rigorously account for

  15. MAP3K1 functionally interacts with Axin1 in the canonical Wnt signalling pathway.

    PubMed

    Sue Ng, Ser; Mahmoudi, Tokameh; Li, Vivian S W; Hatzis, Pantelis; Boersema, Paul J; Mohammed, Shabaz; Heck, Albert J; Clevers, Hans

    2010-01-01

    A central point of regulation in the Wnt/beta-catenin signalling pathway is the formation of the beta-catenin destruction complex. Axin1, an essential negative regulator of Wnt signalling, serves as a scaffold within this complex and is critical for rapid turnover of beta-catenin. To examine the mechanism by which Wnt signalling disables the destruction complex, we used an immunoprecipitation-coupled proteomics approach to identify novel endogenous binding partners of Axin1. We found mitogen-activated protein kinase kinase kinase 1 (MAP3K1) as an Axin1 interactor in Ls174T colorectal cancer (CRC) cells. Importantly, confirmation of this interaction in HEK293T cells indicated that the Axin1-MAP3K1 interaction is induced and modulated by Wnt stimulation. siRNA depletion of MAP3K1 specifically abrogated TCF/LEF-driven transcription and Wnt3A-driven endogenous gene expression in both HEK293T as well as DLD-1 CRC. Expression of ubiquitin ligase mutants of MAP3K1 abrogated TCF/LEF transcription, whereas kinase mutants had no effect in TCF-driven activity, highlighting the essential role of the MAP3K1 E3 ubiquitin ligase activity in regulation of the Wnt/beta-catenin pathway. These results suggest that MAP3K1, previously reported as an Axin1 inter-actor in c-Jun NH(2)-terminal kinase pathway, is also involved in the canonical Wnt signalling pathway and positively regulates expression of Wnt target genes. PMID:20128690

  16. Mapping the functional versatility and fragility of Ras GTPase signaling circuits through in vitro network reconstitution.

    PubMed

    Coyle, Scott M; Lim, Wendell A

    2016-01-01

    The Ras-superfamily GTPases are central controllers of cell proliferation and morphology. Ras signaling is mediated by a system of interacting molecules: upstream enzymes (GEF/GAP) regulate Ras's ability to recruit multiple competing downstream effectors. We developed a multiplexed, multi-turnover assay for measuring the dynamic signaling behavior of in vitro reconstituted H-Ras signaling systems. By including both upstream regulators and downstream effectors, we can systematically map how different network configurations shape the dynamic system response. The concentration and identity of both upstream and downstream signaling components strongly impacted the timing, duration, shape, and amplitude of effector outputs. The distorted output of oncogenic alleles of Ras was highly dependent on the balance of positive (GAP) and negative (GEF) regulators in the system. We found that different effectors interpreted the same inputs with distinct output dynamics, enabling a Ras system to encode multiple unique temporal outputs in response to a single input. We also found that different Ras-to-GEF positive feedback mechanisms could reshape output dynamics in distinct ways, such as signal amplification or overshoot minimization. Mapping of the space of output behaviors accessible to Ras provides a design manual for programming Ras circuits, and reveals how these systems are readily adapted to produce an array of dynamic signaling behaviors. Nonetheless, this versatility comes with a trade-off of fragility, as there exist numerous paths to altered signaling behaviors that could cause disease. PMID:26765565

  17. Specificity of MAP kinase signaling in yeast differentiation involves transient versus sustained MAPK activation.

    PubMed

    Sabbagh, W; Flatauer, L J; Bardwell, A J; Bardwell, L

    2001-09-01

    Signals transmitted by common components often elicit distinct (yet appropriate) outcomes. In yeast, two developmental options-mating and invasive growth-are both regulated by the same MAP kinase cascade. Specificity has been thought to result from specialized roles for the two MAP kinases, Kss1 and Fus3, and because Fus3 prevents Kss1 from gaining access to the mating pathway. Kss1 has been thought to participate in mating only when Fus3 is absent. Instead, we show that Kss1 is rapidly phosphorylated and potently activated by mating pheromone in wild-type cells, and that this is required for normal pheromone-induced gene expression. Signal identity is apparently maintained because active Fus3 limits the extent of Kss1 activation, thereby preventing inappropriate signal crossover. PMID:11583629

  18. A generalized K statistic for estimating phylogenetic signal from shape and other high-dimensional multivariate data.

    PubMed

    Adams, Dean C

    2014-09-01

    Phylogenetic signal is the tendency for closely related species to display similar trait values due to their common ancestry. Several methods have been developed for quantifying phylogenetic signal in univariate traits and for sets of traits treated simultaneously, and the statistical properties of these approaches have been extensively studied. However, methods for assessing phylogenetic signal in high-dimensional multivariate traits like shape are less well developed, and their statistical performance is not well characterized. In this article, I describe a generalization of the K statistic of Blomberg et al. that is useful for quantifying and evaluating phylogenetic signal in highly dimensional multivariate data. The method (K(mult)) is found from the equivalency between statistical methods based on covariance matrices and those based on distance matrices. Using computer simulations based on Brownian motion, I demonstrate that the expected value of K(mult) remains at 1.0 as trait variation among species is increased or decreased, and as the number of trait dimensions is increased. By contrast, estimates of phylogenetic signal found with a squared-change parsimony procedure for multivariate data change with increasing trait variation among species and with increasing numbers of trait dimensions, confounding biological interpretations. I also evaluate the statistical performance of hypothesis testing procedures based on K(mult) and find that the method displays appropriate Type I error and high statistical power for detecting phylogenetic signal in high-dimensional data. Statistical properties of K(mult) were consistent for simulations using bifurcating and random phylogenies, for simulations using different numbers of species, for simulations that varied the number of trait dimensions, and for different underlying models of trait covariance structure. Overall these findings demonstrate that K(mult) provides a useful means of evaluating phylogenetic signal in high

  19. Mapping Cosmic Structure Using 21-cm Hydrogen Signal at Green Bank Telescope

    NASA Astrophysics Data System (ADS)

    Voytek, Tabitha; GBT 21-cm Intensity Mapping Group

    2011-05-01

    We are using the Green Bank Telescope to make 21-cm intensity maps of cosmic structure in a 0.15 Gpc^3 box at redshift of z 1. The intensity mapping technique combines the flux from many galaxies in each pixel, allowing much greater mapping speed than the traditional redshift survey. Measurement is being made at z 1 to take advantage of a window in frequency around 700 MHz where terrestrial radio frequency interference (RFI) is currently at a minimum. This minimum is due to a reallocation of this frequency band from analog television to wide area wireless internet and public service usage. We will report progress of our attempt to detect autocorrelation of the 21-cm signal. The ultimate goal of this mapping is to use Baryon Acoustic Oscillations to provide more precise constraints to dark energy models.

  20. Statistical synthesis of radiometric imaging formation in scanning radiometers with signal weight processing by Kravchenko windows

    NASA Astrophysics Data System (ADS)

    Volosyuk, V. K.; Kravchenko, V. F.; Pavlikov, V. V.; Pustovoit, V. I.

    2014-05-01

    Statistical optimization of the radiometric images (RMIs) algorithms formation in scanning radiometers with weight correction of the antenna amplitude-phase distribution and synchronous sliding strobing of the received noise-like signal by a function describing the antenna pattern corrected by temporal Kravchenko windows is performed for the first time. The ambiguity function (AF) of the scanning radiometer, which determines the RMI quality, is found. It is established that the AF shape substantially depends on the amplitude field distribution (AFD) in the antenna. It is shown that the use of the AFD in the antenna in the form of weight functions (classic and Kravchenko) makes it possible to correct the AF shape and to increase the RMI quality. A simulation of the RMI formation algorithm is performed. It follows from the analysis of simulation data that the use of the weight Kravchenko functions provides higher accuracy of the RMI restoration compared with classic weight functions.

  1. NeuroVault.org: A repository for sharing unthresholded statistical maps, parcellations, and atlases of the human brain.

    PubMed

    Gorgolewski, Krzysztof J; Varoquaux, Gael; Rivera, Gabriel; Schwartz, Yannick; Sochat, Vanessa V; Ghosh, Satrajit S; Maumet, Camille; Nichols, Thomas E; Poline, Jean-Baptiste; Yarkoni, Tal; Margulies, Daniel S; Poldrack, Russell A

    2016-01-01

    NeuroVault.org is dedicated to storing outputs of analyses in the form of statistical maps, parcellations and atlases, a unique strategy that contrasts with most neuroimaging repositories that store raw acquisition data or stereotaxic coordinates. Such maps are indispensable for performing meta-analyses, validating novel methodology, and deciding on precise outlines for regions of interest (ROIs). NeuroVault is open to maps derived from both healthy and clinical populations, as well as from various imaging modalities (sMRI, fMRI, EEG, MEG, PET, etc.). The repository uses modern web technologies such as interactive web-based visualization, cognitive decoding, and comparison with other maps to provide researchers with efficient, intuitive tools to improve the understanding of their results. Each dataset and map is assigned a permanent Universal Resource Locator (URL), and all of the data is accessible through a REST Application Programming Interface (API). Additionally, the repository supports the NIDM-Results standard and has the ability to parse outputs from popular FSL and SPM software packages to automatically extract relevant metadata. This ease of use, modern web-integration, and pioneering functionality holds promise to improve the workflow for making inferences about and sharing whole-brain statistical maps.

  2. NeuroVault.org: A repository for sharing unthresholded statistical maps, parcellations, and atlases of the human brain.

    PubMed

    Gorgolewski, Krzysztof J; Varoquaux, Gael; Rivera, Gabriel; Schwartz, Yannick; Sochat, Vanessa V; Ghosh, Satrajit S; Maumet, Camille; Nichols, Thomas E; Poline, Jean-Baptiste; Yarkoni, Tal; Margulies, Daniel S; Poldrack, Russell A

    2016-01-01

    NeuroVault.org is dedicated to storing outputs of analyses in the form of statistical maps, parcellations and atlases, a unique strategy that contrasts with most neuroimaging repositories that store raw acquisition data or stereotaxic coordinates. Such maps are indispensable for performing meta-analyses, validating novel methodology, and deciding on precise outlines for regions of interest (ROIs). NeuroVault is open to maps derived from both healthy and clinical populations, as well as from various imaging modalities (sMRI, fMRI, EEG, MEG, PET, etc.). The repository uses modern web technologies such as interactive web-based visualization, cognitive decoding, and comparison with other maps to provide researchers with efficient, intuitive tools to improve the understanding of their results. Each dataset and map is assigned a permanent Universal Resource Locator (URL), and all of the data is accessible through a REST Application Programming Interface (API). Additionally, the repository supports the NIDM-Results standard and has the ability to parse outputs from popular FSL and SPM software packages to automatically extract relevant metadata. This ease of use, modern web-integration, and pioneering functionality holds promise to improve the workflow for making inferences about and sharing whole-brain statistical maps. PMID:25869863

  3. MapStats for Kids: Making Geographic Statistical Facts Available to Children

    ERIC Educational Resources Information Center

    Fuhrmann, Sven; MacEachren, Alan; DeBerry, Marshall; Bosley, John; Taylor, Rachael LaPorte; Gahegan, Mark; Downs, Roger

    2005-01-01

    Statistical and geographical literacy is essential for our daily lives. A new web portal for middle school students, published on the federal government statistics website, supports geographic and statistical education by providing age-appropriate online learning activities that teach how to use statistical summaries and their graphic…

  4. Mathematical and Statistical Techniques for Systems Medicine: The Wnt Signaling Pathway as a Case Study.

    PubMed

    MacLean, Adam L; Harrington, Heather A; Stumpf, Michael P H; Byrne, Helen M

    2016-01-01

    The last decade has seen an explosion in models that describe phenomena in systems medicine. Such models are especially useful for studying signaling pathways, such as the Wnt pathway. In this chapter we use the Wnt pathway to showcase current mathematical and statistical techniques that enable modelers to gain insight into (models of) gene regulation and generate testable predictions. We introduce a range of modeling frameworks, but focus on ordinary differential equation (ODE) models since they remain the most widely used approach in systems biology and medicine and continue to offer great potential. We present methods for the analysis of a single model, comprising applications of standard dynamical systems approaches such as nondimensionalization, steady state, asymptotic and sensitivity analysis, and more recent statistical and algebraic approaches to compare models with data. We present parameter estimation and model comparison techniques, focusing on Bayesian analysis and coplanarity via algebraic geometry. Our intention is that this (non-exhaustive) review may serve as a useful starting point for the analysis of models in systems medicine.

  5. Mathematical and Statistical Techniques for Systems Medicine: The Wnt Signaling Pathway as a Case Study.

    PubMed

    MacLean, Adam L; Harrington, Heather A; Stumpf, Michael P H; Byrne, Helen M

    2016-01-01

    The last decade has seen an explosion in models that describe phenomena in systems medicine. Such models are especially useful for studying signaling pathways, such as the Wnt pathway. In this chapter we use the Wnt pathway to showcase current mathematical and statistical techniques that enable modelers to gain insight into (models of) gene regulation and generate testable predictions. We introduce a range of modeling frameworks, but focus on ordinary differential equation (ODE) models since they remain the most widely used approach in systems biology and medicine and continue to offer great potential. We present methods for the analysis of a single model, comprising applications of standard dynamical systems approaches such as nondimensionalization, steady state, asymptotic and sensitivity analysis, and more recent statistical and algebraic approaches to compare models with data. We present parameter estimation and model comparison techniques, focusing on Bayesian analysis and coplanarity via algebraic geometry. Our intention is that this (non-exhaustive) review may serve as a useful starting point for the analysis of models in systems medicine. PMID:26677193

  6. How Can We Evaluate the Accuracy of Small Stream Maps? -Focusing on Sampling Method and Statistical Analysis -

    NASA Astrophysics Data System (ADS)

    Park, J.

    2010-12-01

    statistics such as stream length or stream order. In this study, we suggest linear transactional sampling method and, practically, a stream and road crossing points KHAT- based sampling method to collect field stream position. We also review existing estimation methods and feasibility of the application of the error matrix, and Z-statistics for stream maps, which have not been previously inspected. We find that the visual inspection, hydrological statistics, and headwater-based estimation methods provide insufficient information on the positional accuracy and that the error matrix and KHAT-statistics are effective in evaluating stream network positions by pairing a remote sensing data product with a field reference data, but Z-statistics still has limitation in comparing the two different remote sensing data-based stream map products since the variance converges to zero. In order to compare two stream maps, we develop a new statistical approach which is based on the McNemar test.

  7. Signal processing and statistical descriptive reanalysis of steady state chute-flow experiments

    NASA Astrophysics Data System (ADS)

    truong, hoan; eckert, nicolas; keylock, chris; naaim, mohamed; bellot, hervé

    2014-05-01

    An accurate knowledge of snow rheology is needed for the mitigation against avalanche hazard. Indeed snow avalanches have a significant impact on the livelihoods and economies of alpine communities. To do so, 60 small-scale in-situ flow experiments were performed with various slopes, temperatures and flow depths. The investigation of these data previously seemed to show the dense flow of dry snow may be composed of two layers; a sheared basal layer made of single snow grains and a less sheared upper layer made of large aggregates. These outcomes were mainly based on the mean velocity profile of the flow and on interpretation in terms of rheological behavior of granular materials and snow microstructure [Pierre G. Rognon et al., 2007]. Here, the main objective remains the same, but the rheological and physical viewpoints are put aside to extract as much information contained in the data as possible various using signal processing methods and descriptive statistics methods as the maximum overlap discrete wavelet transform (MODWT), transfer entropy (TE) and maximum cross-correlation (MCC). Specifically, we aim at the improving the velocity estimations as function of the depth particularly the velocity fluctuations around the mean profile to better document the behavior of dense dry snow flows during a steady and uniform chute regime. The data are composed of pairs of voltage signals (right and left), which makes that the velocity is known indirectly only. The MCC method is classically used to determine the time lag between both signals. Previously, the MCC method that showed the mean velocity profile may be fitted by a simple bilinear function [Pierre G. Rognon et al., 2007], but no interesting temporal dynamics could be highlighted. Hence, a new process method was developed to provide velocity series with much better temporal resolution. The process is mainly made of a MODWT-based denoising method and the choice of window size for correlation. The results prove to be

  8. Statistical Mapping of Bursty Bulk Flows in the Magnetosphere Supported by the Virtual Magnetospheric Observatory

    NASA Astrophysics Data System (ADS)

    Merka, J.; Sibeck, D. G.; Narock, T. W.

    2011-12-01

    Fast transient plasma flows in the magnetosphere are usually associated with magnetic reconnection and/or rapid changes in the magnetospheric configuration. Using a common methodology to analyze data from the THEMIS satellites we map the statistical occurrence rate of bursty bulk flows (BBFs) in the magnetosphere. Such a task involves obtaining and processing of large amount of data (5 THEMIS satellites provide measurements since spring of 2007), then writing custom code and searching for intervals of interests. The existence of a Virtual Magnetospheric Observatory (VMO) offers, however, a less laborious alternative. We discuss how the VMO made our research faster and easier and also point out the inherent limitations of the VMO use. The VMO's goal is to help researches by creating a single point of uniform discovery, access, and use of magnetospheric data. Available data can be searched based on various criteria as, for example, spatial location, time of observation, measurement type, parameter values, etc. The results can then be saved, downloaded or displayed as, for example, spatial-temporal plots that quickly reveal where and how often was the searched-for phenomenon observed. Our analysis revealed that the BBFs were found more frequently with increasing distance from Earth and the peak occurrence rate of earthward BBFs was at Xgsm = 29 Re and Ygsm = -2 Re. The tailward BBFs were very rarely observed even between Xgsm = -20 and -30 Re but they occurred over a wide range of local times. The positions with highest BBF occurrence rates differ from previous reports that used IRM and ISEE2 data.

  9. Quantifying time-varying coordination of multimodal speech signals using correlation map analysis.

    PubMed

    Barbosa, Adriano Vilela; Déchaine, Rose-Marie; Vatikiotis-Bateson, Eric; Yehia, Hani Camille

    2012-03-01

    This paper demonstrates an algorithm for computing the instantaneous correlation coefficient between two signals. The algorithm is the computational engine for analyzing the time-varying coordination between signals, which is called correlation map analysis (CMA). Correlation is computed around any pair of points in the two input signals. Thus, coordination can be assessed across a continuous range of temporal offsets and be detected even when changing over time due to temporal fluctuations. The correlation algorithm has two major features: (i) it is structurally similar to a tunable filter, requiring only one parameter to set its cutoff frequency (and sensitivity), (ii) it can be applied either uni-directionally (computing correlation based only on previous samples) or bi-directionally (computing correlation based on both previous and future samples). Computing instantaneous correlation for a range of time offsets between two signals produces a 2D correlation map, in which correlation is characterized as a function of time and temporal offset. Graphic visualization of the correlation map provides rapid assessment of how correspondence patterns progress through time. The utility of the algorithm and of CMA are exemplified using the spatial and temporal coordination of various audible and visible components associated with linguistic performance. PMID:22423712

  10. The Potential for Signal Integration and Processing in Interacting Map Kinase Cascades

    PubMed Central

    Schwacke, John H.; Voit, Eberhard O.

    2009-01-01

    The cellular response to environmental stimuli requires biochemical information processing through which sensory inputs and cellular status are integrated and translated into appropriate responses by way of interacting networks of enzymes. One such network, the Mitogen Activated Protein (MAP) kinase cascade is a highly conserved signal transduction module that propagates signals from cell surface receptors to various cytosolic and nuclear targets by way of a phosphorylation cascade. We have investigated the potential for signal processing within a network of interacting feed-forward kinase cascades typified by the MAP kinase cascade. A genetic algorithm was used to search for sets of kinetic parameters demonstrating representative key input-output patterns of interest. We discuss two of the networks identified in our study, one implementing the exclusive-or function (XOR) and another implementing what we refer to as an in-band detector (IBD) or two-sided threshold. These examples confirm the potential for logic and amplitude-dependent signal processing in interacting MAP kinase cascades demonstrating limited cross-talk. Specifically, the XOR function allows the network to respond to either one, but not both signals simultaneously, while the IBD permits the network to respond exclusively to signals within a given range of strength, and to suppress signals below as well as above this range. The solution to the XOR problem is interesting in that it requires only two interacting pathways, crosstalk at only one layer, and no feedback or explicit inhibition. These types of responses are not only biologically relevant but constitute signal processing modules that can be combined to create other logical functions and that, in contrast to amplification, cannot be achieved with a single cascade or with two non-interacting cascades. Our computational results revealed surprising similarities between experimental data describing the JNK/MKK4/MKK7 pathway and the solution for

  11. SU-E-J-261: Statistical Analysis and Chaotic Dynamics of Respiratory Signal of Patients in BodyFix

    SciTech Connect

    Michalski, D; Huq, M; Bednarz, G; Lalonde, R; Yang, Y; Heron, D

    2014-06-01

    Purpose: To quantify respiratory signal of patients in BodyFix undergoing 4DCT scan with and without immobilization cover. Methods: 20 pairs of respiratory tracks recorded with RPM system during 4DCT scan were analyzed. Descriptive statistic was applied to selected parameters of exhale-inhale decomposition. Standardized signals were used with the delay method to build orbits in embedded space. Nonlinear behavior was tested with surrogate data. Sample entropy SE, Lempel-Ziv complexity LZC and the largest Lyapunov exponents LLE were compared. Results: Statistical tests show difference between scans for inspiration time and its variability, which is bigger for scans without cover. The same is for variability of the end of exhalation and inhalation. Other parameters fail to show the difference. For both scans respiratory signals show determinism and nonlinear stationarity. Statistical test on surrogate data reveals their nonlinearity. LLEs show signals chaotic nature and its correlation with breathing period and its embedding delay time. SE, LZC and LLE measure respiratory signal complexity. Nonlinear characteristics do not differ between scans. Conclusion: Contrary to expectation cover applied to patients in BodyFix appears to have limited effect on signal parameters. Analysis based on trajectories of delay vectors shows respiratory system nonlinear character and its sensitive dependence on initial conditions. Reproducibility of respiratory signal can be evaluated with measures of signal complexity and its predictability window. Longer respiratory period is conducive for signal reproducibility as shown by these gauges. Statistical independence of the exhale and inhale times is also supported by the magnitude of LLE. The nonlinear parameters seem more appropriate to gauge respiratory signal complexity since its deterministic chaotic nature. It contrasts with measures based on harmonic analysis that are blind for nonlinear features. Dynamics of breathing, so crucial for

  12. Universal renormalization-group dynamics at the onset of chaos in logistic maps and nonextensive statistical mechanics

    NASA Astrophysics Data System (ADS)

    Baldovin, F.; Robledo, A.

    2002-10-01

    We uncover the dynamics at the chaos threshold μ∞ of the logistic map and find that it consists of trajectories made of intertwined power laws that reproduce the entire period-doubling cascade that occurs for μ<μ∞. We corroborate this structure analytically via the Feigenbaum renormalization-group (RG) transformation and find that the sensitivity to initial conditions has precisely the form of a q exponential, of which we determine the q index and the q-generalized Lyapunov coefficient λq. Our results are an unequivocal validation of the applicability of the nonextensive generalization of Boltzmann-Gibbs statistical mechanics to critical points of nonlinear maps.

  13. NeuroVault.org: a web-based repository for collecting and sharing unthresholded statistical maps of the human brain.

    PubMed

    Gorgolewski, Krzysztof J; Varoquaux, Gael; Rivera, Gabriel; Schwarz, Yannick; Ghosh, Satrajit S; Maumet, Camille; Sochat, Vanessa V; Nichols, Thomas E; Poldrack, Russell A; Poline, Jean-Baptiste; Yarkoni, Tal; Margulies, Daniel S

    2015-01-01

    Here we present NeuroVault-a web based repository that allows researchers to store, share, visualize, and decode statistical maps of the human brain. NeuroVault is easy to use and employs modern web technologies to provide informative visualization of data without the need to install additional software. In addition, it leverages the power of the Neurosynth database to provide cognitive decoding of deposited maps. The data are exposed through a public REST API enabling other services and tools to take advantage of it. NeuroVault is a new resource for researchers interested in conducting meta- and coactivation analyses.

  14. NeuroVault.org: a web-based repository for collecting and sharing unthresholded statistical maps of the human brain

    PubMed Central

    Gorgolewski, Krzysztof J.; Varoquaux, Gael; Rivera, Gabriel; Schwarz, Yannick; Ghosh, Satrajit S.; Maumet, Camille; Sochat, Vanessa V.; Nichols, Thomas E.; Poldrack, Russell A.; Poline, Jean-Baptiste; Yarkoni, Tal; Margulies, Daniel S.

    2015-01-01

    Here we present NeuroVault—a web based repository that allows researchers to store, share, visualize, and decode statistical maps of the human brain. NeuroVault is easy to use and employs modern web technologies to provide informative visualization of data without the need to install additional software. In addition, it leverages the power of the Neurosynth database to provide cognitive decoding of deposited maps. The data are exposed through a public REST API enabling other services and tools to take advantage of it. NeuroVault is a new resource for researchers interested in conducting meta- and coactivation analyses. PMID:25914639

  15. Diffusion-Based Density-Equalizing Maps: an Interdisciplinary Approach to Visualizing Homicide Rates and Other Georeferenced Statistical Data

    NASA Astrophysics Data System (ADS)

    Mazzitello, Karina I.; Candia, Julián

    2012-12-01

    In every country, public and private agencies allocate extensive funding to collect large-scale statistical data, which in turn are studied and analyzed in order to determine local, regional, national, and international policies regarding all aspects relevant to the welfare of society. One important aspect of that process is the visualization of statistical data with embedded geographical information, which most often relies on archaic methods such as maps colored according to graded scales. In this work, we apply nonstandard visualization techniques based on physical principles. We illustrate the method with recent statistics on homicide rates in Brazil and their correlation to other publicly available data. This physics-based approach provides a novel tool that can be used by interdisciplinary teams investigating statistics and model projections in a variety of fields such as economics and gross domestic product research, public health and epidemiology, sociodemographics, political science, business and marketing, and many others.

  16. Evaluation of Waveform Mapping as a Signal Processing Tool for Quantitative Ultrasonic NDE

    NASA Technical Reports Server (NTRS)

    Johnston, Patrick H.; Kishoni, Doron

    1993-01-01

    The mapping of one pulsed waveform into another, more desirable waveform by the application of a time-domain filter has been employed in a number of NDE situations. The primary goal of these applications has been to improve the range resolution of an ultrasonic signal for detection of echoes arising from particular interfaces masked by the response of the transducer. The work presented here addresses the use of this technique for resolution enhancement in imaging situations and in mapping signals from different transducers to a common target waveform, allowing maintenance of quantitative calibration of ultrasonic systems. We also describe the use of this technique in terms of the frequency analysis of the resulting waveforms.

  17. Exploring relationship between asthma and air pollution: a geospatial methodology using dasymetric mapping, GIS analysis, and spatial statistics

    NASA Astrophysics Data System (ADS)

    Hu, Z.; Liebens, Johan; Rao, Ranga

    2007-06-01

    This paper presents methodology using dasymetric mapping from remotely sensed imagery, geographic information system (GIS), spatial analysis and spatial statistics to explore relationship between asthma and air pollution in the Pensacola metropolitan region of Florida. Health outcome indicators thought to be sensitive to increased exposure of airborne environmental hazards are mortality and morbidity rates for total population asthma patients. Environmental data for the time around the year 1999 include point source pollution sites and emissions, traffic count with emission estimates, and a Landsat ETM+ image. Standardized mortality/morbility ratios (SMRs) were used as dependent variables for the analysis. A centroid map was created from the zip code map with each centroid assigned the corresponding SMR values. Then spatial interpolation using the Kriging method was used to generate continuous SMR surfaces. An emission or point count based kernel density raster map was created from each of the air pollution maps. A raster layer 'greenness' was extracted using tasseled cap transformation from the Landsat ETM+ image. The dasymetric mapping technique was employed to limit the analysis and modeling to the area where human activities occur. The ETM+ image was classified into a thematic land use/cover map and the developed area extracted. A road network was combined with the developed area to generate a buffer (buffer distance=1.5 km). A random sample with enough number of points was generated across the study area and 505 points were found within the developed area and the buffer. Data values at these sample points were extracted and used for statistical modeling. Two spatial autoregressive models (spatial error and spatial lag) were fitted. Both models show relationship between the asthmas outcome indicators and air pollution (positive) and 'greenness' (negative).

  18. Statistically Optimal Approximations of Astronomical Signals: Implications to Classification and Advanced Study of Variable Stars

    NASA Astrophysics Data System (ADS)

    Andronov, I. L.; Chinarova, L. L.; Kudashkina, L. S.; Marsakova, V. I.; Tkachenko, M. G.

    2016-06-01

    We have elaborated a set of new algorithms and programs for advanced time series analysis of (generally) multi-component multi-channel observations with irregularly spaced times of observations, which is a common case for large photometric surveys. Previous self-review on these methods for periodogram, scalegram, wavelet, autocorrelation analysis as well as on "running" or "sub-interval" local approximations were self-reviewed in (2003ASPC..292..391A). For an approximation of the phase light curves of nearly-periodic pulsating stars, we use a Trigonometric Polynomial (TP) fit of the statistically optimal degree and initial period improvement using differential corrections (1994OAP.....7...49A). For the determination of parameters of "characteristic points" (minima, maxima, crossings of some constant value etc.) we use a set of methods self-reviewed in 2005ASPC..335...37A, Results of the analysis of the catalogs compiled using these programs are presented in 2014AASP....4....3A. For more complicated signals, we use "phenomenological approximations" with "special shapes" based on functions defined on sub-intervals rather on the complete interval. E. g. for the Algol-type stars we developed the NAV ("New Algol Variable") algorithm (2012Ap.....55..536A, 2012arXiv1212.6707A, 2015JASS...32..127A), which was compared to common methods of Trigonometric Polynomial Fit (TP) or local Algebraic Polynomial (A) fit of a fixed or (alternately) statistically optimal degree. The method allows determine the minimal set of parameters required for the "General Catalogue of Variable Stars", as well as an extended set of phenomenological and astrophysical parameters which may be used for the classification. Totally more that 1900 variable stars were studied in our group using these methods in a frame of the "Inter-Longitude Astronomy" campaign (2010OAP....23....8A) and the "Ukrainian Virtual Observatory" project (2012KPCB...28...85V).

  19. Motion compensation of optical mapping signals from isolated beating rat hearts

    NASA Astrophysics Data System (ADS)

    Stender, B.; Ernst, F.; Wang, B.; Zhang, Z. X.; Schlaefer, A.

    2013-09-01

    Optical mapping is a well established technique for recording monophasic action potential traces on the epicardial surface of isolated hearts. This measuring technique offers a high spatial resolution but it is sensitive towards myocardial motion. Motion artifacts occur because the mapping between a certain tissue portion sending out fluorescent light and a pixel of the photo detector changes over time. So far this problem has been addressed by suppressing the motion or ratiometric imaging. We developed a different approach to compensate the motion artifacts based on image registration. We could demonstrate how an image deformation field temporally changing with the heart motion could be determined. Using these deformation field time series for image transformation motion signals could be generated for each image pixel which were then successfully applied to remove baseline shift and compensate motion artifacts potentially leading to errors within maps of the first arrival time. The investigation was based on five different rat hearts stained with Di-4-ANEPPS.

  20. Extracting sparse signals from high-dimensional data: A statistical mechanics approach

    NASA Astrophysics Data System (ADS)

    Ramezanali, Mohammad

    Sparse reconstruction algorithms aim to retrieve high-dimensional sparse signals from a limited amount of measurements under suitable conditions. As the number of variables go to infinity, these algorithms exhibit sharp phase transition boundaries where the sparse retrieval breaks down. Several sparse reconstruction algorithms are formulated as optimization problems. Few of the prominent ones among these have been analyzed in the literature by statistical mechanical methods. The function to be optimized plays the role of energy. The treatment involves finite temperature replica mean-field theory followed by the zero temperature limit. Although this approach has been successful in reproducing the algorithmic phase transition boundaries, the replica trick and the non-trivial zero temperature limit obscure the underlying reasons for the failure of the algorithms. In this thesis, we employ the "cavity method" to give an alternative derivation of the phase transition boundaries, working directly in the zero-temperature limit. This approach provides insight into the origin of the different terms in the mean field self-consistency equations. The cavity method naturally generates a local susceptibility which leads to an identity that clearly indicates the existence of two phases. The identity also gives us a novel route to the known parametric expressions for the phase boundary of the Basis Pursuit algorithm and to the new ones for the Elastic Net. These transitions being continuous (second order), we explore the scaling laws and critical exponents that are uniquely determined by the nature of the distribution of the density of the nonzero components of the sparse signal. Not only is the phase boundary of the Elastic Net different from that of the Basis Pursuit, we show that the critical behavior of the two algorithms are from different universality classes.

  1. Application of Polynomial and Radial Basis Function Maps to Signal Masking

    SciTech Connect

    Damiano, B.

    1998-01-01

    The objective of this research was to develop and demonstrate a technique for encrypting information by using a masking signal that closely approximates local ambient noise. Signal masking techniques developed to date have used nonlinear differential equations, spread spectrum, and various modulation schemes to encode information. While these techniques can effectively hide a signal, the resulting masks may not appear as ambient noise to an observer. The advantage of the proposed technique over commonly used masking methods is that the transmitted signal will appear as normal background noise, thus greatly reducing the probability of detection and exploitation. A promising near-term application of this technology presents itself in the area of clandestine minefield reconnaissance in shallow water areas. Shallow water mine-counter-mine (SWMCM) activity is essential for minefield avoidance, efficient minefield clearance, and effective selection of transit lanes within minefields. A key technology area for SWMCM is the development of special sonar waveforms with low probability of exploitation/intercept (LPE/LPI) attributes. In addition to LPE/LPI sonar, this technology has the potential to enable significant improvements in underwater acoustic communications. For SWMCM, the chaotic waveform research provides a mechanism for encrypted communications between a submarine (SSN) and an unmanned underwater vehicle (UUV) via an acoustic channel. Acoustic SSN/UUV communications would eliminate the need for a fiberoptic link between the two vessels, thus increasing the robustness of SWMCM. Similar applications may exist in the areas of radar masking and secure communications. The original approach called for the use of polynomial maps to generate a masking signal. Because polynomial maps were found to have highly restrictive stability criteria, the approach was modified to use radial basis function (RBF) maps. they have shown that stable RBF maps that closely approximate an

  2. High-Performance Signal Detection for Adverse Drug Events using MapReduce Paradigm.

    PubMed

    Fan, Kai; Sun, Xingzhi; Tao, Ying; Xu, Linhao; Wang, Chen; Mao, Xianling; Peng, Bo; Pan, Yue

    2010-01-01

    Post-marketing pharmacovigilance is important for public health, as many Adverse Drug Events (ADEs) are unknown when those drugs were approved for marketing. However, due to the large number of reported drugs and drug combinations, detecting ADE signals by mining these reports is becoming a challenging task in terms of computational complexity. Recently, a parallel programming model, MapReduce has been introduced by Google to support large-scale data intensive applications. In this study, we proposed a MapReduce-based algorithm, for common ADE detection approach, Proportional Reporting Ratio (PRR), and tested it in mining spontaneous ADE reports from FDA. The purpose is to investigate the possibility of using MapReduce principle to speed up biomedical data mining tasks using this pharmacovigilance case as one specific example. The results demonstrated that MapReduce programming model could improve the performance of common signal detection algorithm for pharmacovigilance in a distributed computation environment at approximately liner speedup rates. PMID:21347109

  3. Enhancing Local Climate Projections of Precipitation: Assets and Limitations of Quantile Mapping Techniques for Statistical Downscaling

    NASA Astrophysics Data System (ADS)

    Ivanov, Martin; Kotlarski, Sven; Schär, Christoph

    2015-04-01

    The Swiss CH2011 scenarios provide a portfolio of climate change scenarios for the region of Switzerland, specifically tailored for use in climate impact research. Although widely applied by a variety of end-users, these scenarios are subject to several limitations related to the underlying delta change methodology. Examples are difficulties to appropriately account for changes in the spatio-temporal variability of meteorological fields and for changes in extreme events. The recently launched ELAPSE project (Enhancing local and regional climate change projections for Switzerland) is connected to the EU COST Action VALUE (www.value-cost.eu) and aims at complementing CH2011 by further scenario products, including a bias-corrected version of daily scenarios at the site scale. For this purpose the well-established empirical quantile mapping (QM) methodology is employed. Here, daily temperature and precipitation output of 15 GCM-RCM model chains of the ENSEMBLES project is downscaled and bias-corrected to match observations at weather stations in Switzerland. We consider established QM techniques based on all empirical quantiles or linear interpolation between the empirical percentiles. In an attempt to improve the downscaling of extreme precipitation events, we also apply a parametric approximation of the daily precipitation distribution by a dynamically weighted mixture of a Gamma distribution for the bulk and a Pareto distribution for the right tail for the first time in the context of QM. All techniques are evaluated and intercompared in a cross-validation framework. The statistical downscaling substantially improves virtually all considered distributional and temporal characteristics as well as their spatial distribution. The empirical methods have in general very similar performances. The parametric method does not show an improvement over the empirical ones. Critical sites and seasons are highlighted and discussed. Special emphasis is placed on investigating the

  4. TGF-β activates Erk MAP kinase signalling through direct phosphorylation of ShcA

    PubMed Central

    Lee, Matt K; Pardoux, Cécile; Hall, Marie C; Lee, Pierre S; Warburton, David; Qing, Jing; Smith, Susan M; Derynck, Rik

    2007-01-01

    Erk1/Erk2 MAP kinases are key regulators of cell behaviour and their activation is generally associated with tyrosine kinase signalling. However, TGF-β stimulation also activates Erk MAP kinases through an undefined mechanism, albeit to a much lower level than receptor tyrosine kinase stimulation. We report that upon TGF-β stimulation, the activated TGF-β type I receptor (TβRI) recruits and directly phosphorylates ShcA proteins on tyrosine and serine. This dual phosphorylation results from an intrinsic TβRI tyrosine kinase activity that complements its well-defined serine-threonine kinase function. TGF-β-induced ShcA phosphorylation induces ShcA association with Grb2 and Sos, thereby initiating the well-characterised pathway linking receptor tyrosine kinases with Erk MAP kinases. We also found that TβRI is tyrosine phosphorylated in response to TGF-β. Thus, TβRI, like the TGF-β type II receptor, is a dual-specificity kinase. Recruitment of tyrosine kinase signalling pathways may account for aspects of TGF-β biology that are independent of Smad signalling. PMID:17673906

  5. Mapping the functional versatility and fragility of Ras GTPase signaling circuits through in vitro network reconstitution

    PubMed Central

    Coyle, Scott M; Lim, Wendell A

    2016-01-01

    The Ras-superfamily GTPases are central controllers of cell proliferation and morphology. Ras signaling is mediated by a system of interacting molecules: upstream enzymes (GEF/GAP) regulate Ras’s ability to recruit multiple competing downstream effectors. We developed a multiplexed, multi-turnover assay for measuring the dynamic signaling behavior of in vitro reconstituted H-Ras signaling systems. By including both upstream regulators and downstream effectors, we can systematically map how different network configurations shape the dynamic system response. The concentration and identity of both upstream and downstream signaling components strongly impacted the timing, duration, shape, and amplitude of effector outputs. The distorted output of oncogenic alleles of Ras was highly dependent on the balance of positive (GAP) and negative (GEF) regulators in the system. We found that different effectors interpreted the same inputs with distinct output dynamics, enabling a Ras system to encode multiple unique temporal outputs in response to a single input. We also found that different Ras-to-GEF positive feedback mechanisms could reshape output dynamics in distinct ways, such as signal amplification or overshoot minimization. Mapping of the space of output behaviors accessible to Ras provides a design manual for programming Ras circuits, and reveals how these systems are readily adapted to produce an array of dynamic signaling behaviors. Nonetheless, this versatility comes with a trade-off of fragility, as there exist numerous paths to altered signaling behaviors that could cause disease. DOI: http://dx.doi.org/10.7554/eLife.12435.001 PMID:26765565

  6. Multiple novel prostate cancer susceptibility signals identified by fine-mapping of known risk loci among Europeans.

    PubMed

    Amin Al Olama, Ali; Dadaev, Tokhir; Hazelett, Dennis J; Li, Qiuyan; Leongamornlert, Daniel; Saunders, Edward J; Stephens, Sarah; Cieza-Borrella, Clara; Whitmore, Ian; Benlloch Garcia, Sara; Giles, Graham G; Southey, Melissa C; Fitzgerald, Liesel; Gronberg, Henrik; Wiklund, Fredrik; Aly, Markus; Henderson, Brian E; Schumacher, Fredrick; Haiman, Christopher A; Schleutker, Johanna; Wahlfors, Tiina; Tammela, Teuvo L; Nordestgaard, Børge G; Key, Tim J; Travis, Ruth C; Neal, David E; Donovan, Jenny L; Hamdy, Freddie C; Pharoah, Paul; Pashayan, Nora; Khaw, Kay-Tee; Stanford, Janet L; Thibodeau, Stephen N; Mcdonnell, Shannon K; Schaid, Daniel J; Maier, Christiane; Vogel, Walther; Luedeke, Manuel; Herkommer, Kathleen; Kibel, Adam S; Cybulski, Cezary; Wokołorczyk, Dominika; Kluzniak, Wojciech; Cannon-Albright, Lisa; Brenner, Hermann; Butterbach, Katja; Arndt, Volker; Park, Jong Y; Sellers, Thomas; Lin, Hui-Yi; Slavov, Chavdar; Kaneva, Radka; Mitev, Vanio; Batra, Jyotsna; Clements, Judith A; Spurdle, Amanda; Teixeira, Manuel R; Paulo, Paula; Maia, Sofia; Pandha, Hardev; Michael, Agnieszka; Kierzek, Andrzej; Govindasami, Koveela; Guy, Michelle; Lophatonanon, Artitaya; Muir, Kenneth; Viñuela, Ana; Brown, Andrew A; Freedman, Mathew; Conti, David V; Easton, Douglas; Coetzee, Gerhard A; Eeles, Rosalind A; Kote-Jarai, Zsofia

    2015-10-01

    Genome-wide association studies (GWAS) have identified numerous common prostate cancer (PrCa) susceptibility loci. We have fine-mapped 64 GWAS regions known at the conclusion of the iCOGS study using large-scale genotyping and imputation in 25 723 PrCa cases and 26 274 controls of European ancestry. We detected evidence for multiple independent signals at 16 regions, 12 of which contained additional newly identified significant associations. A single signal comprising a spectrum of correlated variation was observed at 39 regions; 35 of which are now described by a novel more significantly associated lead SNP, while the originally reported variant remained as the lead SNP only in 4 regions. We also confirmed two association signals in Europeans that had been previously reported only in East-Asian GWAS. Based on statistical evidence and linkage disequilibrium (LD) structure, we have curated and narrowed down the list of the most likely candidate causal variants for each region. Functional annotation using data from ENCODE filtered for PrCa cell lines and eQTL analysis demonstrated significant enrichment for overlap with bio-features within this set. By incorporating the novel risk variants identified here alongside the refined data for existing association signals, we estimate that these loci now explain ∼38.9% of the familial relative risk of PrCa, an 8.9% improvement over the previously reported GWAS tag SNPs. This suggests that a significant fraction of the heritability of PrCa may have been hidden during the discovery phase of GWAS, in particular due to the presence of multiple independent signals within the same region. PMID:26025378

  7. Multiple novel prostate cancer susceptibility signals identified by fine-mapping of known risk loci among Europeans.

    PubMed

    Amin Al Olama, Ali; Dadaev, Tokhir; Hazelett, Dennis J; Li, Qiuyan; Leongamornlert, Daniel; Saunders, Edward J; Stephens, Sarah; Cieza-Borrella, Clara; Whitmore, Ian; Benlloch Garcia, Sara; Giles, Graham G; Southey, Melissa C; Fitzgerald, Liesel; Gronberg, Henrik; Wiklund, Fredrik; Aly, Markus; Henderson, Brian E; Schumacher, Fredrick; Haiman, Christopher A; Schleutker, Johanna; Wahlfors, Tiina; Tammela, Teuvo L; Nordestgaard, Børge G; Key, Tim J; Travis, Ruth C; Neal, David E; Donovan, Jenny L; Hamdy, Freddie C; Pharoah, Paul; Pashayan, Nora; Khaw, Kay-Tee; Stanford, Janet L; Thibodeau, Stephen N; Mcdonnell, Shannon K; Schaid, Daniel J; Maier, Christiane; Vogel, Walther; Luedeke, Manuel; Herkommer, Kathleen; Kibel, Adam S; Cybulski, Cezary; Wokołorczyk, Dominika; Kluzniak, Wojciech; Cannon-Albright, Lisa; Brenner, Hermann; Butterbach, Katja; Arndt, Volker; Park, Jong Y; Sellers, Thomas; Lin, Hui-Yi; Slavov, Chavdar; Kaneva, Radka; Mitev, Vanio; Batra, Jyotsna; Clements, Judith A; Spurdle, Amanda; Teixeira, Manuel R; Paulo, Paula; Maia, Sofia; Pandha, Hardev; Michael, Agnieszka; Kierzek, Andrzej; Govindasami, Koveela; Guy, Michelle; Lophatonanon, Artitaya; Muir, Kenneth; Viñuela, Ana; Brown, Andrew A; Freedman, Mathew; Conti, David V; Easton, Douglas; Coetzee, Gerhard A; Eeles, Rosalind A; Kote-Jarai, Zsofia

    2015-10-01

    Genome-wide association studies (GWAS) have identified numerous common prostate cancer (PrCa) susceptibility loci. We have fine-mapped 64 GWAS regions known at the conclusion of the iCOGS study using large-scale genotyping and imputation in 25 723 PrCa cases and 26 274 controls of European ancestry. We detected evidence for multiple independent signals at 16 regions, 12 of which contained additional newly identified significant associations. A single signal comprising a spectrum of correlated variation was observed at 39 regions; 35 of which are now described by a novel more significantly associated lead SNP, while the originally reported variant remained as the lead SNP only in 4 regions. We also confirmed two association signals in Europeans that had been previously reported only in East-Asian GWAS. Based on statistical evidence and linkage disequilibrium (LD) structure, we have curated and narrowed down the list of the most likely candidate causal variants for each region. Functional annotation using data from ENCODE filtered for PrCa cell lines and eQTL analysis demonstrated significant enrichment for overlap with bio-features within this set. By incorporating the novel risk variants identified here alongside the refined data for existing association signals, we estimate that these loci now explain ∼38.9% of the familial relative risk of PrCa, an 8.9% improvement over the previously reported GWAS tag SNPs. This suggests that a significant fraction of the heritability of PrCa may have been hidden during the discovery phase of GWAS, in particular due to the presence of multiple independent signals within the same region.

  8. Multiple novel prostate cancer susceptibility signals identified by fine-mapping of known risk loci among Europeans

    PubMed Central

    Amin Al Olama, Ali; Dadaev, Tokhir; Hazelett, Dennis J.; Li, Qiuyan; Leongamornlert, Daniel; Saunders, Edward J.; Stephens, Sarah; Cieza-Borrella, Clara; Whitmore, Ian; Benlloch Garcia, Sara; Giles, Graham G.; Southey, Melissa C.; Fitzgerald, Liesel; Gronberg, Henrik; Wiklund, Fredrik; Aly, Markus; Henderson, Brian E.; Schumacher, Fredrick; Haiman, Christopher A.; Schleutker, Johanna; Wahlfors, Tiina; Tammela, Teuvo L.; Nordestgaard, Børge G.; Key, Tim J.; Travis, Ruth C.; Neal, David E.; Donovan, Jenny L.; Hamdy, Freddie C.; Pharoah, Paul; Pashayan, Nora; Khaw, Kay-Tee; Stanford, Janet L.; Thibodeau, Stephen N.; Mcdonnell, Shannon K.; Schaid, Daniel J.; Maier, Christiane; Vogel, Walther; Luedeke, Manuel; Herkommer, Kathleen; Kibel, Adam S.; Cybulski, Cezary; Wokołorczyk, Dominika; Kluzniak, Wojciech; Cannon-Albright, Lisa; Brenner, Hermann; Butterbach, Katja; Arndt, Volker; Park, Jong Y.; Sellers, Thomas; Lin, Hui-Yi; Slavov, Chavdar; Kaneva, Radka; Mitev, Vanio; Batra, Jyotsna; Clements, Judith A.; Spurdle, Amanda; Teixeira, Manuel R.; Paulo, Paula; Maia, Sofia; Pandha, Hardev; Michael, Agnieszka; Kierzek, Andrzej; Govindasami, Koveela; Guy, Michelle; Lophatonanon, Artitaya; Muir, Kenneth; Viñuela, Ana; Brown, Andrew A.; Freedman, Mathew; Conti, David V.; Easton, Douglas; Coetzee, Gerhard A.; Eeles, Rosalind A.; Kote-Jarai, Zsofia

    2015-01-01

    Genome-wide association studies (GWAS) have identified numerous common prostate cancer (PrCa) susceptibility loci. We have fine-mapped 64 GWAS regions known at the conclusion of the iCOGS study using large-scale genotyping and imputation in 25 723 PrCa cases and 26 274 controls of European ancestry. We detected evidence for multiple independent signals at 16 regions, 12 of which contained additional newly identified significant associations. A single signal comprising a spectrum of correlated variation was observed at 39 regions; 35 of which are now described by a novel more significantly associated lead SNP, while the originally reported variant remained as the lead SNP only in 4 regions. We also confirmed two association signals in Europeans that had been previously reported only in East-Asian GWAS. Based on statistical evidence and linkage disequilibrium (LD) structure, we have curated and narrowed down the list of the most likely candidate causal variants for each region. Functional annotation using data from ENCODE filtered for PrCa cell lines and eQTL analysis demonstrated significant enrichment for overlap with bio-features within this set. By incorporating the novel risk variants identified here alongside the refined data for existing association signals, we estimate that these loci now explain ∼38.9% of the familial relative risk of PrCa, an 8.9% improvement over the previously reported GWAS tag SNPs. This suggests that a significant fraction of the heritability of PrCa may have been hidden during the discovery phase of GWAS, in particular due to the presence of multiple independent signals within the same region. PMID:26025378

  9. Statistical pattern analysis of blood vessel features on retina images and its application to blood vessel mapping algorithms.

    PubMed

    Ying, Huajun; Wang, Xing; Liu, Jyh-Charn

    2014-01-01

    Computer based modeling and analysis of blood vessel (BV) networks is essential for automated detection and tracking of anomalies and structural changes in retina images. Among many published techniques for automated BV mapping, optimal selection of thresholds to delineate BV pixels from their background pixels remains an open problem. In this paper we propose a novel representation of a BV pixel feature, daisy graph, using rotational contrast transform (RCT), and two feature descriptors energy E(p) and symmetry difference S(p) of the daisy graph. Non-BV pixels are separated from BV and boundary pixels based on E(p). Fitness of the lognormal distribution to S(p) of BV pixels with negative E(p) has been tested extensively for images in the STARE and DRIVE databases. Based on statistical pattern analysis in the feature space, we propose a fast self-calibrated BV mapping algorithm which achieve comparable and statistically sound performance as contemporary solutions. PMID:25571441

  10. SRS 2010 Vegetation Inventory GeoStatistical Mapping Results for Custom Reaction Intensity and Total Dead Fuels.

    SciTech Connect

    Edwards, Lloyd A.; Paresol, Bernard

    2014-09-01

    This report of the geostatistical analysis results of the fire fuels response variables, custom reaction intensity and total dead fuels is but a part of an SRS 2010 vegetation inventory project. For detailed description of project, theory and background including sample design, methods, and results please refer to USDA Forest Service Savannah River Site internal report “SRS 2010 Vegetation Inventory GeoStatistical Mapping Report”, (Edwards & Parresol 2013).

  11. A quantitative analysis of signal reproduction from cylinder recordings measured via noncontact full surface mapping.

    PubMed

    Nascè, Antony; Hill, Martyn; McBride, John W; Boltryk, Peter J

    2008-10-01

    Sound reproduction via a noncontact surface mapping technique has great potential for sound archives, aiming to digitize content from early sound recordings such as wax cylinders, which may otherwise be "unplayable" with a stylus. If the noncontact techniques are to be considered a viable solution for sound archivists, a method for quantifying the quality of the reproduced signal needs to be developed. In this study, a specially produced test cylinder recording, encoded with sinusoids, provides the basis for the first quantitative analysis of signal reproduction from the noncontact full surface mapping method. The sampling and resolution of the measurement system are considered with respect to the requirements for digital archiving of cylinder recordings. Two different methods of audio signal estimation from a discrete groove cross section are described and rated in terms of signal-to-noise ratio and total harmonic distortion. Noncontact and stylus methods of sound reproduction are then compared using the same test cylinder. It is shown that noncontact methods appear to have distinct advantages over stylus reproduction, in terms of reduced harmonic distortion and lower frequency modulation. PMID:19062844

  12. A scalable neuroinformatics data flow for electrophysiological signals using MapReduce

    PubMed Central

    Jayapandian, Catherine; Wei, Annan; Ramesh, Priya; Zonjy, Bilal; Lhatoo, Samden D.; Loparo, Kenneth; Zhang, Guo-Qiang; Sahoo, Satya S.

    2015-01-01

    Data-driven neuroscience research is providing new insights in progression of neurological disorders and supporting the development of improved treatment approaches. However, the volume, velocity, and variety of neuroscience data generated from sophisticated recording instruments and acquisition methods have exacerbated the limited scalability of existing neuroinformatics tools. This makes it difficult for neuroscience researchers to effectively leverage the growing multi-modal neuroscience data to advance research in serious neurological disorders, such as epilepsy. We describe the development of the Cloudwave data flow that uses new data partitioning techniques to store and analyze electrophysiological signal in distributed computing infrastructure. The Cloudwave data flow uses MapReduce parallel programming algorithm to implement an integrated signal data processing pipeline that scales with large volume of data generated at high velocity. Using an epilepsy domain ontology together with an epilepsy focused extensible data representation format called Cloudwave Signal Format (CSF), the data flow addresses the challenge of data heterogeneity and is interoperable with existing neuroinformatics data representation formats, such as HDF5. The scalability of the Cloudwave data flow is evaluated using a 30-node cluster installed with the open source Hadoop software stack. The results demonstrate that the Cloudwave data flow can process increasing volume of signal data by leveraging Hadoop Data Nodes to reduce the total data processing time. The Cloudwave data flow is a template for developing highly scalable neuroscience data processing pipelines using MapReduce algorithms to support a variety of user applications. PMID:25852536

  13. A scalable neuroinformatics data flow for electrophysiological signals using MapReduce.

    PubMed

    Jayapandian, Catherine; Wei, Annan; Ramesh, Priya; Zonjy, Bilal; Lhatoo, Samden D; Loparo, Kenneth; Zhang, Guo-Qiang; Sahoo, Satya S

    2015-01-01

    Data-driven neuroscience research is providing new insights in progression of neurological disorders and supporting the development of improved treatment approaches. However, the volume, velocity, and variety of neuroscience data generated from sophisticated recording instruments and acquisition methods have exacerbated the limited scalability of existing neuroinformatics tools. This makes it difficult for neuroscience researchers to effectively leverage the growing multi-modal neuroscience data to advance research in serious neurological disorders, such as epilepsy. We describe the development of the Cloudwave data flow that uses new data partitioning techniques to store and analyze electrophysiological signal in distributed computing infrastructure. The Cloudwave data flow uses MapReduce parallel programming algorithm to implement an integrated signal data processing pipeline that scales with large volume of data generated at high velocity. Using an epilepsy domain ontology together with an epilepsy focused extensible data representation format called Cloudwave Signal Format (CSF), the data flow addresses the challenge of data heterogeneity and is interoperable with existing neuroinformatics data representation formats, such as HDF5. The scalability of the Cloudwave data flow is evaluated using a 30-node cluster installed with the open source Hadoop software stack. The results demonstrate that the Cloudwave data flow can process increasing volume of signal data by leveraging Hadoop Data Nodes to reduce the total data processing time. The Cloudwave data flow is a template for developing highly scalable neuroscience data processing pipelines using MapReduce algorithms to support a variety of user applications. PMID:25852536

  14. An application of mapping neural networks and a digital signal processor for cochlear neuroprostheses.

    PubMed

    Zadák, J; Unbehauen, R

    1993-01-01

    Cochlear neuroprostheses strive to restore the sensation of hearing to patients with a profound sensorineural deafness. They exhibit a stimulation of the surviving auditory nerve neurons by electrical currents delivered through electrodes placed on or within the cochlea. The present article describes a new method for an efficient derivation of the required information from the incoming speech signal necessary for the implant stimulation. Also some realization aspects of the new approach are addressed. In the new strategy, a multilayer neural network is employed in the formant frequency estimation having some suitable speech signal descriptors as particular input signals. The proposed method allows us a fast formant frequency estimation necessary for the implant stimulation. With the developed strategy, the prosthesis can be adjusted to the environment which the patient is supposed to live in. Moreover, the neural network concept offers us an alternative for dealing with the areas of neural loss or "holes" in the frequency map of the patient's ear.

  15. RKIP regulates MAP kinase signaling in cells with defective B-Raf activity.

    PubMed

    Zeng, Lingchun; Ehrenreiter, Karin; Menon, Jyotsana; Menard, Ray; Kern, Florian; Nakazawa, Yoko; Bevilacqua, Elena; Imamoto, Akira; Baccarini, Manuela; Rosner, Marsha Rich

    2013-05-01

    MAP kinase (MAPK) signaling results from activation of Raf kinases in response to external or internal stimuli. Here, we demonstrate that Raf kinase inhibitory protein (RKIP) regulates the activation of MAPK when B-Raf signaling is defective. We used multiple models including mouse embryonic fibroblasts (MEFs) and primary keratinocytes from RKIP- or Raf-deficient mice as well as allografts in mice to investigate the mechanism. Loss of B-Raf protein or activity significantly reduces MAPK activation in these cells. We show that RKIP depletion can rescue the compromised ERK activation and promote proliferation, and this rescue occurs through a Raf-1 dependent mechanism. These results provide formal evidence that RKIP is a bona fide regulator of Raf-1. We propose a new model in which RKIP plays a key role in regulating the ability of cells to signal through Raf-1 to ERK in B-Raf compromised cells.

  16. 3D statistical parametric mapping of EEG source spectra by means of variable resolution electromagnetic tomography (VARETA).

    PubMed

    Bosch-Bayard, J; Valdés-Sosa, P; Virues-Alba, T; Aubert-Vázquez, E; John, E R; Harmony, T; Riera-Díaz, J; Trujillo-Barreto, N

    2001-04-01

    This article describes a new method for 3D QEEG tomography in the frequency domain. A variant of Statistical Parametric Mapping is presented for source log spectra. Sources are estimated by means of a Discrete Spline EEG inverse solution known as Variable Resolution Electromagnetic Tomography (VARETA). Anatomical constraints are incorporated by the use of the Montreal Neurological Institute (MNI) probabilistic brain atlas. Efficient methods are developed for frequency domain VARETA in order to estimate the source spectra for the set of 10(3)-10(5) voxels that comprise an EEG/MEG inverse solution. High resolution source Z spectra are then defined with respect to the age dependent mean and standard deviations of each voxel, which are summarized as regression equations calculated from the Cuban EEG normative database. The statistical issues involved are addressed by the use of extreme value statistics. Examples are shown that illustrate the potential clinical utility of the methods herein developed.

  17. Landslide susceptibility mapping using a bivariate statistical model in a tropical hilly area of southeastern Brazil

    NASA Astrophysics Data System (ADS)

    Araújo, J. P. C.; DA Silva, L. M.; Dourado, F. A. D.; Fernandes, N.

    2015-12-01

    Landslides are the most damaging natural hazard in the mountainous region of Rio de Janeiro State in Brazil, responsible for thousands of deaths and important financial and environmental losses. However, this region has currently few landslide susceptibility maps implemented on an adequate scale. Identification of landslide susceptibility areas is fundamental in successful land use planning and management practices to reduce risk. This paper applied the Bayes' theorem based on weight of evidence (WoE) using 8 landslide-related factors in a geographic information system (GIS) for landslide susceptibility mapping. 378 landslide locations were identified and mapped on a selected basin in the city of Nova Friburgo, triggered by the January 2011 rainfall event. The landslide scars were divided into two subsets: training and validation subsets. The 8 landslide-related factors weighted by WoE were performed using chi-square test to indicate which variables are conditionally independent of each other to be used in the final map. Finally, the maps of weighted factors were summed up to construct the landslide susceptibility map and validated by the validation landslide subset. According to the results, slope, aspect and contribution area showed the higher positive spatial correlation with landslides. In the landslide susceptibility map, 21% of the area presented very low and low susceptibilities with 3% of the validation scars, 41% presented medium susceptibility with 22% of the validation scars and 38% presented high and very high susceptibilities with 75% of the validation scars. The very high susceptibility class stands for 16% of the basin area and has 54% of the all scars. The approach used in this study can be considered very useful since 75% of the area affected by landslides was included in the high and very high susceptibility classes.

  18. Definition of an Enhanced Map-Matching Algorithm for Urban Environments with Poor GNSS Signal Quality

    PubMed Central

    Jiménez, Felipe; Monzón, Sergio; Naranjo, Jose Eugenio

    2016-01-01

    Vehicle positioning is a key factor for numerous information and assistance applications that are included in vehicles and for which satellite positioning is mainly used. However, this positioning process can result in errors and lead to measurement uncertainties. These errors come mainly from two sources: errors and simplifications of digital maps and errors in locating the vehicle. From that inaccurate data, the task of assigning the vehicle’s location to a link on the digital map at every instant is carried out by map-matching algorithms. These algorithms have been developed to fulfil that need and attempt to amend these errors to offer the user a suitable positioning. In this research; an algorithm is developed that attempts to solve the errors in positioning when the Global Navigation Satellite System (GNSS) signal reception is frequently lost. The algorithm has been tested with satisfactory results in a complex urban environment of narrow streets and tall buildings where errors and signal reception losses of the GPS receiver are frequent. PMID:26861320

  19. Definition of an Enhanced Map-Matching Algorithm for Urban Environments with Poor GNSS Signal Quality.

    PubMed

    Jiménez, Felipe; Monzón, Sergio; Naranjo, Jose Eugenio

    2016-02-04

    Vehicle positioning is a key factor for numerous information and assistance applications that are included in vehicles and for which satellite positioning is mainly used. However, this positioning process can result in errors and lead to measurement uncertainties. These errors come mainly from two sources: errors and simplifications of digital maps and errors in locating the vehicle. From that inaccurate data, the task of assigning the vehicle's location to a link on the digital map at every instant is carried out by map-matching algorithms. These algorithms have been developed to fulfil that need and attempt to amend these errors to offer the user a suitable positioning. In this research; an algorithm is developed that attempts to solve the errors in positioning when the Global Navigation Satellite System (GNSS) signal reception is frequently lost. The algorithm has been tested with satisfactory results in a complex urban environment of narrow streets and tall buildings where errors and signal reception losses of the GPS receiver are frequent.

  20. Definition of an Enhanced Map-Matching Algorithm for Urban Environments with Poor GNSS Signal Quality.

    PubMed

    Jiménez, Felipe; Monzón, Sergio; Naranjo, Jose Eugenio

    2016-01-01

    Vehicle positioning is a key factor for numerous information and assistance applications that are included in vehicles and for which satellite positioning is mainly used. However, this positioning process can result in errors and lead to measurement uncertainties. These errors come mainly from two sources: errors and simplifications of digital maps and errors in locating the vehicle. From that inaccurate data, the task of assigning the vehicle's location to a link on the digital map at every instant is carried out by map-matching algorithms. These algorithms have been developed to fulfil that need and attempt to amend these errors to offer the user a suitable positioning. In this research; an algorithm is developed that attempts to solve the errors in positioning when the Global Navigation Satellite System (GNSS) signal reception is frequently lost. The algorithm has been tested with satisfactory results in a complex urban environment of narrow streets and tall buildings where errors and signal reception losses of the GPS receiver are frequent. PMID:26861320

  1. A new integrated statistical approach to the diagnostic use of two-dimensional maps.

    PubMed

    Marengo, Emilio; Robotti, Elisa; Gianotti, Valentina; Righetti, Pier Giorgio; Cecconi, Daniela; Domenici, Enrico

    2003-01-01

    Two-dimensional (2-D) electrophoresis is a very useful technique for the analysis of proteins in biological tissues. The complexity of the 2-D maps obtained causes many difficulties in the comparison of different samples. A new method is proposed for comparing different 2-D maps, based on five steps: (i) the digitalisation of the image; (ii) the transformation of the digitalised map in a fuzzy entity, in order to consider the variability of the 2-D electrophoretic separation; (iii) the calculation of a similarity index for each pair of maps; (iv) the analysis by multidimensional scaling of the previously obtained similarity matrix; (v) the analysis by classification or cluster analysis techniques of the resulting map co-ordinates. The method adopted was first tested on some simulated samples in order to evaluate its sensitivity to small changes in the spots position and size. The optimal setting of the method parameters was also investigated. Finally, the method was successfully applied to a series of real samples corresponding to the electrophoretic bidimensional analysis of sera from normal and nicotine-treated rats. Multidimensional scaling allowed the separation of the two classes of samples without any misclassification. PMID:12652595

  2. Statistical-mechanical analysis of self-organization and pattern formation during the development of visual maps

    NASA Astrophysics Data System (ADS)

    Obermayer, K.; Blasdel, G. G.; Schulten, K.

    1992-05-01

    We report a detailed analytical and numerical model study of pattern formation during the development of visual maps, namely, the formation of topographic maps and orientation and ocular dominance columns in the striate cortex. Pattern formation is described by a stimulus-driven Markovian process, the self-organizing feature map. This algorithm generates topologically correct maps between a space of (visual) input signals and an array of formal ``neurons,'' which in our model represents the cortex. We define order parameters that are a function of the set of visual stimuli an animal perceives, and we demonstrate that the formation of orientation and ocular dominance columns is the result of a global instability of the retinoptic projection above a critical value of these order parameters. We characterize the spatial structure of the emerging patterns by power spectra, correlation functions, and Gabor transforms, and we compare model predictions with experimental data obtained from the striate cortex of the macaque monkey with optical imaging. Above the critical value of the order parameters the model predicts a lateral segregation of the striate cortex into (i) binocular regions with linear changes in orientation preference, where iso-orientation slabs run perpendicular to the ocular dominance bands, and (ii) monocular regions with low orientation specificity, which contain the singularities of the orientation map. Some of these predictions have already been verified by experiments.

  3. A MAP OF THE INTEGRATED SACHS-WOLFE SIGNAL FROM LUMINOUS RED GALAXIES

    SciTech Connect

    Granett, Benjamin R.; Neyrinck, Mark C.; Szapudi, Istvan

    2009-08-10

    We construct a map of the time derivative of the gravitational potential traced by Sloan Digital Sky Survey luminous red galaxies (LRGs). The potential decays on large scales due to cosmic acceleration, leaving an imprint on cosmic microwave background (CMB) radiation through the integrated Sachs-Wolfe (ISW) effect. With a template fit, we directly measure this signature on the CMB at a 2{sigma} confidence level. The measurement is consistent with the cross-correlation statistic, strengthening the claim that dark energy is indeed the cause of the correlation. This new approach potentially simplifies the cosmological interpretation. Our constructed linear ISW map shows no evidence for degree-scale cold and hot spots associated with supervoid and supercluster structures. This suggests that the linear ISW effect in a concordance {lambda}CDM cosmology is insufficient to explain the strong CMB imprints from these structures that we previously reported.

  4. Mapping

    ERIC Educational Resources Information Center

    Kinney, Douglas M.; McIntosh, Willard L.

    1978-01-01

    Geologic mapping in the United States increased by about one-quarter in the past year. Examinations of mapping trends were in the following categories: (1) Mapping at scales of 1:100, 000; (2) Metric-scale base maps; (3) International mapping, and (4) Planetary mapping. (MA)

  5. The Research of Feature Extraction Method of Liver Pathological Image Based on Multispatial Mapping and Statistical Properties

    PubMed Central

    Liu, Huiling; Xia, Bingbing; Yi, Dehui

    2016-01-01

    We propose a new feature extraction method of liver pathological image based on multispatial mapping and statistical properties. For liver pathological images of Hematein Eosin staining, the image of R and B channels can reflect the sensitivity of liver pathological images better, while the entropy space and Local Binary Pattern (LBP) space can reflect the texture features of the image better. To obtain the more comprehensive information, we map liver pathological images to the entropy space, LBP space, R space, and B space. The traditional Higher Order Local Autocorrelation Coefficients (HLAC) cannot reflect the overall information of the image, so we propose an average correction HLAC feature. We calculate the statistical properties and the average gray value of pathological images and then update the current pixel value as the absolute value of the difference between the current pixel gray value and the average gray value, which can be more sensitive to the gray value changes of pathological images. Lastly the HLAC template is used to calculate the features of the updated image. The experiment results show that the improved features of the multispatial mapping have the better classification performance for the liver cancer. PMID:27022407

  6. Diffeomorphic metric mapping and probabilistic atlas generation of hybrid diffusion imaging based on BFOR signal basis.

    PubMed

    Du, Jia; Hosseinbor, A Pasha; Chung, Moo K; Bendlin, Barbara B; Suryawanshi, Gaurav; Alexander, Andrew L; Qiu, Anqi

    2014-10-01

    We first propose a large deformation diffeomorphic metric mapping algorithm to align multiple b-value diffusion weighted imaging (mDWI) data, specifically acquired via hybrid diffusion imaging (HYDI). We denote this algorithm as LDDMM-HYDI. We then propose a Bayesian probabilistic model for estimating the white matter atlas from HYDIs. We adopt the work given in Hosseinbor et al. (2013) and represent the q-space diffusion signal with the Bessel Fourier orientation reconstruction (BFOR) signal basis. The BFOR framework provides the representation of mDWI in the q-space and the analytic form of the emsemble average propagator (EAP) reconstruction, as well as reduces memory requirement. In addition, since the BFOR signal basis is orthonormal, the L(2) norm that quantifies the differences in the q-space signals of any two mDWI datasets can be easily computed as the sum of the squared differences in the BFOR expansion coefficients. In this work, we show that the reorientation of the q-space signal due to spatial transformation can be easily defined on the BFOR signal basis. We incorporate the BFOR signal basis into the LDDMM framework and derive the gradient descent algorithm for LDDMM-HYDI with explicit orientation optimization. Additionally, we extend the previous Bayesian atlas estimation framework for scalar-valued images to HYDIs and derive the expectation-maximization algorithm for solving the HYDI atlas estimation problem. Using real HYDI datasets, we show that the Bayesian model generates the white matter atlas with anatomical details. Moreover, we show that it is important to consider the variation of mDWI reorientation due to a small change in diffeomorphic transformation in the LDDMM-HYDI optimization and to incorporate the full information of HYDI for aligning mDWI. Finally, we show that the LDDMM-HYDI outperforms the LDDMM algorithm with diffusion tensors generated from each shell of HYDI.

  7. Infants Rapidly Learn Word-Referent Mappings via Cross-Situational Statistics

    ERIC Educational Resources Information Center

    Smith, Linda; Yu, Chen

    2008-01-01

    First word learning should be difficult because any pairing of a word and scene presents the learner with an infinite number of possible referents. Accordingly, theorists of children's rapid word learning have sought constraints on word-referent mappings. These constraints are thought to work by enabling learners to resolve the ambiguity inherent…

  8. Statistical mapping of the effect of knee extension on thigh muscle viscoelastic properties using magnetic resonance elastography.

    PubMed

    Barnhill, Eric; Kennedy, Paul; Hammer, Steven; van Beek, Edwin J R; Brown, Colin; Roberts, Neil

    2013-12-01

    Skeletal muscle viscoelastic properties reflect muscle microstructure and neuromuscular activation. Elastographic methods, including magnetic resonance elastography, have been used to characterize muscle viscoelastic properties in terms of region of interest (ROI) measurements. The present study extended this approach to create thresholded pixel-by-pixel maps of viscoelastic properties of skeletal muscle during rest and knee extension in eleven subjects. ROI measurements were taken for individual quadricep muscles and the quadriceps region as a whole, and the viscoelastic parameter map pixels were statistically tested at positive false discovery rate q ≤ 0.25. ROI measurements showed significant (p ≤ 0.05) increase in storage modulus (G') and loss modulus (G″), with G″ increasing more than G', in agreement with previous findings. The q-value maps further identified the vastus intermedius as the primary driver of this change, with greater G″/G' increase than surrounding regions. Additionally, a cluster of significant decrease in G″/G' was found in the region of vastus lateralis below the fulcrum point of the lift. Viscoelastic parameter mapping of contracted muscle allows new insight into the relationship between physiology, neuromuscular activation, and human performance.

  9. Statistical analysis of polarizing maps of blood plasma laser images for the diagnostics of malignant formations

    NASA Astrophysics Data System (ADS)

    Ungurian, V. P.; Ivashchuk, O. I.; Ushenko, V. O.

    2012-01-01

    This work is aimed at searching the interconnections between the statistic structure of blood plasma microscopic images and manifestations of optical anisotropy of liquid crystal protein network. The model of linear birefringence of albumin and globulin crystals underlies in the ground of this work. The results of investigating the interrelation between statistical moments of the 1st-4th order are presented that characterize the coordinate distributions of polarization ellipticity of laser images of blood plasma smears and pathological changes in human organism. The diagnostic criteria of breast cancer nascency and its severity degree differentiation are determined.

  10. Statistical mapping of zones of focused groundwater/surface-water exchange using fiber-optic distributed temperature sensing

    USGS Publications Warehouse

    Mwakanyamale, Kisa; Day-Lewis, Frederick D.; Slater, Lee D.

    2013-01-01

    Fiber-optic distributed temperature sensing (FO-DTS) increasingly is used to map zones of focused groundwater/surface-water exchange (GWSWE). Previous studies of GWSWE using FO-DTS involved identification of zones of focused GWSWE based on arbitrary cutoffs of FO-DTS time-series statistics (e.g., variance, cross-correlation between temperature and stage, or spectral power). New approaches are needed to extract more quantitative information from large, complex FO-DTS data sets while concurrently providing an assessment of uncertainty associated with mapping zones of focused GSWSE. Toward this end, we present a strategy combining discriminant analysis (DA) and spectral analysis (SA). We demonstrate the approach using field experimental data from a reach of the Columbia River adjacent to the Hanford 300 Area site. Results of the combined SA/DA approach are shown to be superior to previous results from qualitative interpretation of FO-DTS spectra alone.

  11. Statistical epistasis between candidate gene alleles for complex tuber traits in an association mapping population of tetraploid potato.

    PubMed

    Li, Li; Paulo, Maria-João; van Eeuwijk, Fred; Gebhardt, Christiane

    2010-11-01

    Association mapping using DNA-based markers is a novel tool in plant genetics for the analysis of complex traits. Potato tuber yield, starch content, starch yield and chip color are complex traits of agronomic relevance, for which carbohydrate metabolism plays an important role. At the functional level, the genes and biochemical pathways involved in carbohydrate metabolism are among the best studied in plants. Quantitative traits such as tuber starch and sugar content are therefore models for association genetics in potato based on candidate genes. In an association mapping experiment conducted with a population of 243 tetraploid potato varieties and breeding clones, we previously identified associations between individual candidate gene alleles and tuber starch content, starch yield and chip quality. In the present paper, we tested 190 DNA markers at 36 loci scored in the same association mapping population for pairwise statistical epistatic interactions. Fifty marker pairs were associated mainly with tuber starch content and/or starch yield, at a cut-off value of q ≤ 0.20 for the experiment-wide false discovery rate (FDR). Thirteen marker pairs had an FDR of q ≤ 0.10. Alleles at loci encoding ribulose-bisphosphate carboxylase/oxygenase activase (Rca), sucrose phosphate synthase (Sps) and vacuolar invertase (Pain1) were most frequently involved in statistical epistatic interactions. The largest effect on tuber starch content and starch yield was observed for the paired alleles Pain1-8c and Rca-1a, explaining 9 and 10% of the total variance, respectively. The combination of these two alleles increased the means of tuber starch content and starch yield. Biological models to explain the observed statistical epistatic interactions are discussed.

  12. Report on 3- and 4-Point Correlation Statistics in COBE DMR Anisotropy Maps

    NASA Technical Reports Server (NTRS)

    Hinshaw, Gary; Gorski, Krzystof M.; Bennett, Charles L.; Banday, Anthony J.

    1996-01-01

    As part of the work performed under this contract, we have computed the 3- and 4-point correlation functions of the COBE-DMR 2-year and 4-year anisotropy maps. The results of our work showed that the 3-point correlation function is consistent with zero and that the 4-point function is not a very sensitive probe of non-Gaussian behavior in the COBE-DMR data.

  13. Gaussian statistics of the cosmic microwave background: Correlation of temperature extrema in the COBE DMR two-year sky maps

    NASA Technical Reports Server (NTRS)

    Kogut, A.; Banday, A. J.; Bennett, C. L.; Hinshaw, G.; Lubin, P. M.; Smoot, G. F.

    1995-01-01

    We use the two-point correlation function of the extrema points (peaks and valleys) in the Cosmic Background Explorer (COBE) Differential Microwave Radiometers (DMR) 2 year sky maps as a test for non-Gaussian temperature distribution in the cosmic microwave background anisotropy. A maximum-likelihood analysis compares the DMR data to n = 1 toy models whose random-phase spherical harmonic components a(sub lm) are drawn from either Gaussian, chi-square, or log-normal parent populations. The likelihood of the 53 GHz (A+B)/2 data is greatest for the exact Gaussian model. There is less than 10% chance that the non-Gaussian models tested describe the DMR data, limited primarily by type II errors in the statistical inference. The extrema correlation function is a stronger test for this class of non-Gaussian models than topological statistics such as the genus.

  14. Overlapping functions of the MAP4K family kinases Hppy and Msn in Hippo signaling

    PubMed Central

    Li, Shuangxi; Cho, Yong Suk; Yue, Tao; Ip, Y Tony; Jiang, Jin

    2015-01-01

    The Hippo (Hpo) tumor suppressor pathway is an evolutionarily conserved signaling pathway that controls tissue growth and organ size in species ranging from Drosophila to human, and its malfunction has been implicated in many types of human cancer. In this study, we conducted a kinome screen and identified Happyhour (Hppy)/MAP4K3 as a novel player in the Hpo pathway. Our biochemical study showed that Hppy binds and phosphorylates Wts. Our genetic experiments suggest that Hppy acts in parallel and partial redundantly with Misshapen (Msn)/MAP4K4 to regulate Yki nuclear localization and Hpo target gene expression in Drosophila wing imaginal discs. Furthermore, we showed that cytoskeleton stress restricts Yki nuclear localization through Hppy and Msn when Hpo activity is compromised, thus providing an explanation for the Wts-dependent but Hpo-independent regulation of Yki in certain contexts. Our study has unraveled an additional layer of complexity in the Hpo signaling pathway and laid down a foundation for exploring how different upstream regulators feed into the core Hpo pathway. PMID:27462435

  15. Statistical mapping of metabolites in the medial wall of the brain: a proton echo planar spectroscopic imaging study.

    PubMed

    Niddam, David M; Tsai, Shang-Yueh; Lin, Yi-Ru

    2015-03-01

    With magnetic resonance spectroscopic imaging (MRSI), it is possible to simultaneously map distributions of several brain metabolites with relatively good spatial resolution in a short time. Although other functional imaging modalities have taken advantage of population-based inferences using spatially extended statistics, this approach remains little utilized for MRSI. In this study, statistical nonparametric mapping (SnPM) was applied to two-dimensional MRSI data from the medial walls of the human brain to assess the effect of normal aging on metabolite concentrations. The effects of different preprocessing steps on these results were then explored. Short echo time MRSI of left and right medial walls was acquired in conjunction with absolute quantification of total choline, total creatine (tCr), glutamate and glutamine, myo-inositol, and N-acetyl-aspartate. Individual images were spatially warped to a common anatomical frame of reference. Age effects were assessed within SnPM as were the effects of voxel subsampling, variance smoothing, and spatial smoothing. The main findings were: (1) regions in the bilateral dorsal anterior cingulate and in the left posterior cingulate exhibited higher tCr concentrations with age; (2) voxel subsampling but not spatial smoothing enhanced the cluster-level statistical sensitivity; and (3) variance smoothing was of little benefit in this study. Our study shows that spatially extended statistics can yield information about regional-specific changes in metabolite concentrations obtained by short echo time MRSI. This opens up the possibility for systematic comparisons of metabolites in the medial wall of the brain.

  16. Glial and neuronal Semaphorin signaling instruct the development of a functional myotopic map for Drosophila walking

    PubMed Central

    Syed, Durafshan Sakeena; Gowda, Swetha B.M.; Reddy, O Venkateswara; Reichert, Heinrich; VijayRaghavan, K

    2016-01-01

    Motoneurons developmentally acquire appropriate cellular architectures that ensure connections with postsynaptic muscles and presynaptic neurons. In Drosophila, leg motoneurons are organized as a myotopic map, where their dendritic domains represent the muscle field. Here, we investigate mechanisms underlying development of aspects of this myotopic map, required for walking. A behavioral screen identified roles for Semaphorins (Sema) and Plexins (Plex) in walking behavior. Deciphering this phenotype, we show that PlexA/Sema1a mediates motoneuron axon branching in ways that differ in the proximal femur and distal tibia, based on motoneuronal birth order. Importantly, we show a novel role for glia in positioning dendrites of specific motoneurons; PlexB/Sema2a is required for dendritic positioning of late-born motoneurons but not early-born motoneurons. These findings indicate that communication within motoneurons and between glia and motoneurons, mediated by the combined action of different Plexin/Semaphorin signaling systems, are required for the formation of a functional myotopic map. DOI: http://dx.doi.org/10.7554/eLife.11572.001 PMID:26926907

  17. Atmospheric velocity spectral width measurements using the statistical distribution of pulsed CO2 lidar return signal intensities

    NASA Technical Reports Server (NTRS)

    Ancellet, Gerard M.; Menzies, Robert T.; Grant, William B.

    1989-01-01

    A pulsed CO2 lidar with coherent detection has been used to measure the correlation time of backscatter from an ensemble of atmospheric aerosol particles which are illuminated by the pulsed radiation. The correlation time of the backscatter of the return signal, which is directly related to the velocity spectral width, can be used to study the velocity structure constant of atmospheric turbulence and wind shear. Various techniques for correlation time measurement are discussed, and several measurement results are presented for the technique using the information contained in the statistical distribution of a set of lidar return signal intensities.

  18. Research Update: Spatially resolved mapping of electronic structure on atomic level by multivariate statistical analysis

    SciTech Connect

    Belianinov, Alex; Panchapakesan, G.; Lin, Wenzhi; Sales, Brian C.; Sefat, Athena Safa; Jesse, Stephen; Pan, Minghu; Kalinin, Sergei V.

    2014-12-02

    Atomic level spatial variability of electronic structure in Fe-based superconductor FeTe0.55Se0.45 (Tc = 15 K) is explored using current-imaging tunneling-spectroscopy. Multivariate statistical analysis of the data differentiates regions of dissimilar electronic behavior that can be identified with the segregation of chalcogen atoms, as well as boundaries between terminations and near neighbor interactions. Subsequent clustering analysis allows identification of the spatial localization of these dissimilar regions. Similar statistical analysis of modeled calculated density of states of chemically inhomogeneous FeTe1 x Sex structures further confirms that the two types of chalcogens, i.e., Te and Se, can be identified by their electronic signature and differentiated by their local chemical environment. This approach allows detailed chemical discrimination of the scanning tunneling microscopy data including separation of atomic identities, proximity, and local configuration effects and can be universally applicable to chemically and electronically inhomogeneous surfaces.

  19. Research Update: Spatially resolved mapping of electronic structure on atomic level by multivariate statistical analysis

    NASA Astrophysics Data System (ADS)

    Belianinov, Alex; Ganesh, Panchapakesan; Lin, Wenzhi; Sales, Brian C.; Sefat, Athena S.; Jesse, Stephen; Pan, Minghu; Kalinin, Sergei V.

    2014-12-01

    Atomic level spatial variability of electronic structure in Fe-based superconductor FeTe0.55Se0.45 (Tc = 15 K) is explored using current-imaging tunneling-spectroscopy. Multivariate statistical analysis of the data differentiates regions of dissimilar electronic behavior that can be identified with the segregation of chalcogen atoms, as well as boundaries between terminations and near neighbor interactions. Subsequent clustering analysis allows identification of the spatial localization of these dissimilar regions. Similar statistical analysis of modeled calculated density of states of chemically inhomogeneous FeTe1-xSex structures further confirms that the two types of chalcogens, i.e., Te and Se, can be identified by their electronic signature and differentiated by their local chemical environment. This approach allows detailed chemical discrimination of the scanning tunneling microscopy data including separation of atomic identities, proximity, and local configuration effects and can be universally applicable to chemically and electronically inhomogeneous surfaces.

  20. Mapping sea ice using reflected GNSS signals in a bistatic radar system

    NASA Astrophysics Data System (ADS)

    Chew, Clara; Zuffada, Cinzia; Shah, Rashmi; Mannucci, Anthony

    2016-04-01

    Global Navigation Satellite System (GNSS) signals can be used as a kind of bistatic radar, with receivers opportunistically recording ground-reflected signals transmitted by the GNSS satellites themselves. This technique, GNSS-Reflectometry (GNSS-R), has primarily been explored using receivers flown on aircraft or balloons, or in modeling studies. Last year's launch of the TechDemoSat-1 (TDS-1) satellite represents an enormous opportunity to investigate the potential of using spaceborne GNSS receivers to sense changes in the land and ocean surface. Here, we examine the ability of reflected GNSS signals to estimate sea ice extent and sea ice age, as well as comment on the possibility of using GNSS-R to detect leads and polynyas within the ice. In particular, we quantify how the peak power of Delay Doppler Maps (DDMs) generated within the GNSS receiver responds as the satellite flies over the Polar Regions. To compute the effective peak power of each DDM, we first normalize the peak power of the DDM by the noise floor. We also correct for antenna gain, range, and incidence angle. Once these corrections are made, the effective peak power across DDMs may be used as a proxy for changes in surface permittivity and surface roughness. We compare our calculations of reflected power to existing sea ice remote sensing products such as data from the SSMI/S as well as Landsat imagery. Our analysis shows that GNSS reflections are extremely sensitive to the sea ice edge, with increases in reflected power of more than 10 dB relative to reflected power over the open ocean. As the sea ice ages, it thickens and roughens, and reflected power decreases, though it does not decrease below the power over the open ocean. Given the observed sensitivity of GNSS reflections to small features over land and the sensitivity to the sea ice edge, we hypothesize that reflection data could help map the temporal evolution of leads and polynyas.

  1. Mapping Transient Hyperventilation Induced Alterations with Estimates of the Multi-Scale Dynamics of BOLD Signal

    PubMed Central

    Kiviniemi, Vesa; Remes, Jukka; Starck, Tuomo; Nikkinen, Juha; Haapea, Marianne; Silven, Olli; Tervonen, Osmo

    2009-01-01

    Temporal blood oxygen level dependent (BOLD) contrast signals in functional MRI during rest may be characterized by power spectral distribution (PSD) trends of the form 1/fα. Trends with 1/f characteristics comprise fractal properties with repeating oscillation patterns in multiple time scales. Estimates of the fractal properties enable the quantification of phenomena that may otherwise be difficult to measure, such as transient, non-linear changes. In this study it was hypothesized that the fractal metrics of 1/f BOLD signal trends can map changes related to dynamic, multi-scale alterations in cerebral blood flow (CBF) after a transient hyperventilation challenge. Twenty-three normal adults were imaged in a resting-state before and after hyperventilation. Different variables (1/f trend constant α, fractal dimension Df, and, Hurst exponent H) characterizing the trends were measured from BOLD signals. The results show that fractal metrics of the BOLD signal follow the fractional Gaussian noise model, even during the dynamic CBF change that follows hyperventilation. The most dominant effect on the fractal metrics was detected in grey matter, in line with previous hyperventilation vaso-reactivity studies. The α was able to differentiate also blood vessels from grey matter changes. Df was most sensitive to grey matter. H correlated with default mode network areas before hyperventilation but this pattern vanished after hyperventilation due to a global increase in H. In the future, resting-state fMRI combined with fractal metrics of the BOLD signal may be used for analyzing multi-scale alterations of cerebral blood flow. PMID:19636388

  2. Landslide susceptibility mapping in Mawat area, Kurdistan Region, NE Iraq: a comparison of different statistical models

    NASA Astrophysics Data System (ADS)

    Othman, A. A.; Gloaguen, R.; Andreani, L.; Rahnama, M.

    2015-03-01

    During the last decades, expansion of settlements into areas prone to landslides in Iraq has increased the importance of accurate hazard assessment. Susceptibility mapping provides information about hazardous locations and thus helps to potentially prevent infrastructure damage due to mass wasting. The aim of this study is to evaluate and compare frequency ratio (FR), weight of evidence (WOE), logistic regression (LR) and probit regression (PR) approaches in combination with new geomorphological indices to determine the landslide susceptibility index (LSI). We tested these four methods in Mawat area, Kurdistan Region, NE Iraq, where landslides occur frequently. For this purpose, we evaluated 16 geomorphological, geological and environmental predicting factors mainly derived from the advanced spaceborne thermal emission and reflection radiometer (ASTER) satellite. The available reference inventory includes 351 landslides representing a cumulative surface of 3.127 km2. This reference inventory was mapped from QuickBird data by manual delineation and partly verified by field survey. The areas under curve (AUC) of the receiver operating characteristic (ROC), and relative landslide density (R index) show that all models perform similarly and that focus should be put on the careful selection of proxies. The results indicate that the lithology and the slope aspects play major roles for landslide occurrences. Furthermore, this paper demonstrates that using hypsometric integral as a prediction factor instead of slope curvature gives better results and increases the accuracy of the LSI.

  3. Statistical assessment of bi-exponential diffusion weighted imaging signal characteristics induced by intravoxel incoherent motion in malignant breast tumors

    PubMed Central

    Wong, Oi Lei; Lo, Gladys G.; Chan, Helen H. L.; Wong, Ting Ting; Cheung, Polly S. Y.

    2016-01-01

    Background The purpose of this study is to statistically assess whether bi-exponential intravoxel incoherent motion (IVIM) model better characterizes diffusion weighted imaging (DWI) signal of malignant breast tumor than mono-exponential Gaussian diffusion model. Methods 3 T DWI data of 29 malignant breast tumors were retrospectively included. Linear least-square mono-exponential fitting and segmented least-square bi-exponential fitting were used for apparent diffusion coefficient (ADC) and IVIM parameter quantification, respectively. F-test and Akaike Information Criterion (AIC) were used to statistically assess the preference of mono-exponential and bi-exponential model using region-of-interests (ROI)-averaged and voxel-wise analysis. Results For ROI-averaged analysis, 15 tumors were significantly better fitted by bi-exponential function and 14 tumors exhibited mono-exponential behavior. The calculated ADC, D (true diffusion coefficient) and f (pseudo-diffusion fraction) showed no significant differences between mono-exponential and bi-exponential preferable tumors. Voxel-wise analysis revealed that 27 tumors contained more voxels exhibiting mono-exponential DWI decay while only 2 tumors presented more bi-exponential decay voxels. ADC was consistently and significantly larger than D for both ROI-averaged and voxel-wise analysis. Conclusions Although the presence of IVIM effect in malignant breast tumors could be suggested, statistical assessment shows that bi-exponential fitting does not necessarily better represent the DWI signal decay in breast cancer under clinically typical acquisition protocol and signal-to-noise ratio (SNR). Our study indicates the importance to statistically examine the breast cancer DWI signal characteristics in practice. PMID:27709078

  4. Dual role for membrane localization in yeast MAP kinase cascade activation and its contribution to signaling fidelity.

    PubMed

    Lamson, Rachel E; Takahashi, Satoe; Winters, Matthew J; Pryciak, Peter M

    2006-03-21

    Distinct MAP kinase pathways in yeast share several signaling components , including the PAK Ste20 and the MAPKKK Ste11, yet signaling is specific. Mating pheromones trigger an initial step in which Ste20 activates Ste11 , and this requires plasma membrane recruitment of the MAP kinase cascade scaffold protein, Ste5 . Here, we demonstrate an additional role for Ste5 membrane localization. Once Ste11 is activated, signaling through the mating pathway remains minimal but is substantially amplified when Ste5 is recruited to the membrane either by the Gbetagamma dimer or by direct membrane targeting, even to internal membranes. Ste11 signaling is also amplified by Ste5 oligomerization and by a hyperactivating mutation in the Ste7 binding region of Ste5. We suggest a model in which membrane recruitment of Ste5 concentrates its binding partners and thereby amplifies signaling through the kinase cascade. We find similar behavior in the osmotically responsive HOG pathway. Remarkably, while both pheromone and hyperosmotic stimuli amplify signaling from constitutively active Ste11, the resulting signaling output remains pathway specific. These findings suggest a common mode of regulation in which pathway stimuli both initiate and amplify MAP kinase cascade signaling. The regulation of rate-limiting steps that lie after a branchpoint from shared components helps ensure signaling specificity.

  5. Statistical parametric mapping of the regional distribution and ontogenetic scaling of foot pressures during walking in Asian elephants (Elephas maximus).

    PubMed

    Panagiotopoulou, Olga; Pataky, Todd C; Hill, Zoe; Hutchinson, John R

    2012-05-01

    Foot pressure distributions during locomotion have causal links with the anatomical and structural configurations of the foot tissues and the mechanics of locomotion. Elephant feet have five toes bound in a flexible pad of fibrous tissue (digital cushion). Does this specialized foot design control peak foot pressures in such giant animals? And how does body size, such as during ontogenetic growth, influence foot pressures? We addressed these questions by studying foot pressure distributions in elephant feet and their correlation with body mass and centre of pressure trajectories, using statistical parametric mapping (SPM), a neuro-imaging technology. Our results show a positive correlation between body mass and peak pressures, with the highest pressures dominated by the distal ends of the lateral toes (digits 3, 4 and 5). We also demonstrate that pressure reduction in the elephant digital cushion is a complex interaction of its viscoelastic tissue structure and its centre of pressure trajectories, because there is a tendency to avoid rear 'heel' contact as an elephant grows. Using SPM, we present a complete map of pressure distributions in elephant feet during ontogeny by performing statistical analysis at the pixel level across the entire plantar/palmar surface. We hope that our study will build confidence in the potential clinical and scaling applications of mammalian foot pressures, given our findings in support of a link between regional peak pressures and pathogenesis in elephant feet.

  6. Statistical parametric mapping of the regional distribution and ontogenetic scaling of foot pressures during walking in Asian elephants (Elephas maximus).

    PubMed

    Panagiotopoulou, Olga; Pataky, Todd C; Hill, Zoe; Hutchinson, John R

    2012-05-01

    Foot pressure distributions during locomotion have causal links with the anatomical and structural configurations of the foot tissues and the mechanics of locomotion. Elephant feet have five toes bound in a flexible pad of fibrous tissue (digital cushion). Does this specialized foot design control peak foot pressures in such giant animals? And how does body size, such as during ontogenetic growth, influence foot pressures? We addressed these questions by studying foot pressure distributions in elephant feet and their correlation with body mass and centre of pressure trajectories, using statistical parametric mapping (SPM), a neuro-imaging technology. Our results show a positive correlation between body mass and peak pressures, with the highest pressures dominated by the distal ends of the lateral toes (digits 3, 4 and 5). We also demonstrate that pressure reduction in the elephant digital cushion is a complex interaction of its viscoelastic tissue structure and its centre of pressure trajectories, because there is a tendency to avoid rear 'heel' contact as an elephant grows. Using SPM, we present a complete map of pressure distributions in elephant feet during ontogeny by performing statistical analysis at the pixel level across the entire plantar/palmar surface. We hope that our study will build confidence in the potential clinical and scaling applications of mammalian foot pressures, given our findings in support of a link between regional peak pressures and pathogenesis in elephant feet. PMID:22496296

  7. Domain Specificity of MAP3K Family Members, MLK and Tak1, for JNK Signaling in Drosophila

    PubMed Central

    Stronach, Beth; Lennox, Ashley L.; Garlena, Rebecca A.

    2014-01-01

    A highly diverse set of protein kinases functions as early responders in the mitogen- and stress-activated protein kinase (MAPK/SAPK) signaling pathways. For instance, humans possess 14 MAPK kinase kinases (MAP3Ks) that activate Jun kinase (JNK) signaling downstream. A major challenge is to decipher the selective and redundant functions of these upstream MAP3Ks. Taking advantage of the relative simplicity of Drosophila melanogaster as a model system, we assessed MAP3K signaling specificity in several JNK-dependent processes during development and stress response. Our approach was to generate molecular chimeras between two MAP3K family members, the mixed lineage kinase, Slpr, and the TGF-β activated kinase, Tak1, which share 32% amino acid identity across the kinase domain but otherwise differ in sequence and domain structure, and then test the contributions of various domains for protein localization, complementation of mutants, and activation of signaling. We found that overexpression of the wild-type kinases stimulated JNK signaling in alternate contexts, so cells were capable of responding to both MAP3Ks, but with distinct outcomes. Relative to wild-type, the catalytic domain swaps compensated weakly or not at all, despite having a shared substrate, the JNK kinase Hep. Tak1 C-terminal domain-containing constructs were inhibitory in Tak1 signaling contexts, including tumor necrosis factor-dependent cell death and innate immune signaling; however, depressing antimicrobial gene expression did not necessarily cause phenotypic susceptibility to infection. These same constructs were neutral in the context of Slpr-dependent developmental signaling, reflecting differential subcellular protein localization and by inference, point of activation. Altogether, our findings suggest that the selective deployment of a particular MAP3K can be attributed in part to its inherent sequence differences, cellular localization, and binding partner availability. PMID:24429281

  8. Mapping dynamic protein interactions in MAP kinase signaling using live-cell fluorescence fluctuation spectroscopy and imaging.

    PubMed

    Slaughter, Brian D; Schwartz, Joel W; Li, Rong

    2007-12-18

    Fluorescence correlation spectroscopy (FCS), fluorescence cross-correlation spectroscopy (FCCS), and photon counting histograms (PCH) are fluctuation methods that emerged recently as potentially useful tools for obtaining parameters of molecular dynamics, interactions, and oligomerization in vivo. Here, we report the successful implementation of FCS, FCCS, and PCH in live yeast cells using fluorescent protein-tagged proteins expressed from their native chromosomal loci, examining cytosolic dynamics and interactions among components of the mitogen activated protein kinase (MAPK) cascade, a widely occurring signaling motif, in response to mating pheromone. FCS analysis detailed the diffusion characteristics and mobile concentrations of MAPK proteins. FCCS analysis using EGFP and mCherry-tagged protein pairs observed the interactions of Ste7 (MAPK kinase) with the MAPKs, Fus3 or Kss1, and of the scaffold protein, Ste5, with Ste7 and Ste11 (MAPK kinase kinase) in the cytosol, providing in vivo constants of their binding equilibrium. The interaction of Ste5 with Fus3 in the cytosol was below the limit of detection, suggesting a weak interaction, if it exists, with K(d) >400-500 nM. Using PCH, we show that cytosolic Ste5 were mostly monomers. Artificial dimerization of Ste5, as confirmed by PCH, using a dimerizing tag, stimulated the interaction between Ste5 and Fus3. Native Ste5 was found to bind Fus3 preferentially at the cortex in pheromone-treated cells, as detected by fluorescence resonance energy transfer (FRET). These results provide a quantitative spatial map of MAPK complexes in vivo and directly support the model that membrane association and regulation of the Ste5 scaffold are critical steps in MAPK activation. PMID:18077328

  9. The characterisation of blood rotation in a human heart chamber based on statistical analysis of vorticity maps

    NASA Astrophysics Data System (ADS)

    Wong, Kelvin K. L.; Kelso, Richard M.; Worthley, Stephen G.; Sanders, Prashanthan; Mazumdar, Jagannath; Abbott, Derek

    2008-12-01

    Modelling of non-stationary cardiac structures is complicated by the complexity of their intrinsic and extrinsic motion. The first known study of haemodynamics due to the beating of heart was made by Leonardo Da Vinci, giving the idea of fluid-solid interaction by describing how vortices develop during cardiac structural interaction with the blood. Heart morphology affects in changes of cardio dynamics during the systolic and diastolic phrases. In a chamber of the heart, vortices are discovered to exist as the result of the unique morphological changes of the cardiac chamber wall by using flow-imaging techniques such as phase contrast magnetic resonance imaging. The first part of this paper attempts to quantify vortex characteristics by means of calculating vorticity numerically and devising two dimensional vortical flow maps. The technique relies on determining the properties of vorticity using a statistical quantification of the flow maps and comparison of these quantities based on different scenarios. As the characteristics of our vorticity maps vary depending on the phase of a cardiac cycle, there is a need for robust quantification method to analyse vorticity. In the second part of the paper, the approach is then utilised for examining vortices within the human right atrium. Our study has shown that a proper quantification of vorticity for the flow field can indicate the strength and number of vortices within a heart chamber.

  10. Mapping of Planetary Surface Age Based on Crater Statistics Obtained by AN Automatic Detection Algorithm

    NASA Astrophysics Data System (ADS)

    Salih, A. L.; Mühlbauer, M.; Grumpe, A.; Pasckert, J. H.; Wöhler, C.; Hiesinger, H.

    2016-06-01

    The analysis of the impact crater size-frequency distribution (CSFD) is a well-established approach to the determination of the age of planetary surfaces. Classically, estimation of the CSFD is achieved by manual crater counting and size determination in spacecraft images, which, however, becomes very time-consuming for large surface areas and/or high image resolution. With increasing availability of high-resolution (nearly) global image mosaics of planetary surfaces, a variety of automated methods for the detection of craters based on image data and/or topographic data have been developed. In this contribution a template-based crater detection algorithm is used which analyses image data acquired under known illumination conditions. Its results are used to establish the CSFD for the examined area, which is then used to estimate the absolute model age of the surface. The detection threshold of the automatic crater detection algorithm is calibrated based on a region with available manually determined CSFD such that the age inferred from the manual crater counts corresponds to the age inferred from the automatic crater detection results. With this detection threshold, the automatic crater detection algorithm can be applied to a much larger surface region around the calibration area. The proposed age estimation method is demonstrated for a Kaguya Terrain Camera image mosaic of 7.4 m per pixel resolution of the floor region of the lunar crater Tsiolkovsky, which consists of dark and flat mare basalt and has an area of nearly 10,000 km2. The region used for calibration, for which manual crater counts are available, has an area of 100 km2. In order to obtain a spatially resolved age map, CSFDs and surface ages are computed for overlapping quadratic regions of about 4.4 x 4.4 km2 size offset by a step width of 74 m. Our constructed surface age map of the floor of Tsiolkovsky shows age values of typically 3.2-3.3 Ga, while for small regions lower (down to 2.9 Ga) and higher

  11. Mobility statistics and automated hazard mapping for debris flows and rock avalanches

    USGS Publications Warehouse

    Griswold, Julia P.; Iverson, Richard M.

    2008-01-01

    Power-law equations that are physically motivated and statistically tested and calibrated provide a basis for forecasting areas likely to be inundated by debris flows, rock avalanches, and lahars with diverse volumes. The equations A=α1V2/3 and B=α2V2/3 are based on the postulate that the maximum valley cross-sectional area (A) and total valley planimetric area (B) likely to be inundated by a flow depend only on its volume (V) and the topography of the flow path. Testing of these equations involves determining whether or not they fit data for documented flows satisfactorily, and calibration entails determining best-fit values of the coefficients α1 and α2 for debris flows, rock avalanches, and lahars. This report describes statistical testing and calibration of the equations by using field data compiled from many sources, and it describes application of the equations to delineation of debris-flow hazard zones. Statistical results show that for each type of flow (debris flows, rock avalanches, and lahars), the dependence of A and B on V is described well by power laws with exponents equal to 2/3. This value of the exponent produces fits that are effectively indistinguishable from the best fits obtained by using adjustable power-law exponents. Statistically calibrated values of the coefficients α1 and α2 provide scale-invariant indices of the relative mobilities of rock avalanches (α1 = 0.2, α2 = 20), nonvolcanic debris flows (α1 = 0.1, α2 = 20), and lahars (α1 = 0.05, α2 = 200). These values show, for example, that a lahar of specified volume can be expected to inundate a planimetric area ten times larger than that inundated by a rock avalanche or nonvolcanic debris flow of the same volume. The utility of the calibrated debris-flow inundation equations A=0.1V2/3 and B=20V2/3 is demonstrated by using them within the GIS program LAHARZ to delineate nested hazard zones for future debris flows in an area bordering the Umpqua River in the south-central Oregon

  12. The ElderSmile TimeMap: Benefits of Connecting Statistics With Time and Place.

    PubMed

    Kum, Susan S; Wang, Hua; Wang, Peng; Jin, Zhu; De La Cruz, Leydis; Northridge, Mary E; Kunzel, Carol; Marshall, Stephen E; Metcalf, Sara S

    2015-09-01

    Community-based programs are critical for locally targeted public health education and accessible service delivery. Deriving useful information from such programs is important for their own evaluation and improvement and may facilitate research collaboration with partners and experts. Here we present an interactive Web-based application designed for a community-based oral health outreach program called ElderSmile to demonstrate how data can be summarized, filtered, compared, and visualized by time and place to inform program planning, evaluation, and research. The ElderSmile TimeMap ( http://www.acsu.buffalo.edu/∼smetcalf/resources/timemap.html ) is an emergent product of a US National Institutes of Health-funded collaboration of knowledge sharing among multidisciplinary team members at the University at Buffalo, Columbia University, and New York University. PMID:26180989

  13. Statistical characteristics of the Poincaré return times for a one-dimensional nonhyperbolic map

    NASA Astrophysics Data System (ADS)

    Anishchenko, V. S.; Khairulin, M.; Strelkova, G.; Kurths, J.

    2011-08-01

    Characteristics of the Poincaré return times are considered in a one-dimensional cubic map with a chaotic nonhyperbolic attractor. Two approaches, local one (Kac's theorem) and global one related with the AP-dimension estimation of return times, are used. The return times characteristics are studied in the presence of external noise. The characteristics of Poincaré recurrences are compared with the form of probability measure and the complete correspondence of the obtained results with the mathematical theory is shown. The influence of the attractor crisis on the return time characteristics is also analyzed. The obtained results have a methodical and educational significance and can be used for solving a number of applied tasks.

  14. The ElderSmile TimeMap: Benefits of Connecting Statistics With Time and Place

    PubMed Central

    Kum, Susan S.; Wang, Hua; Wang, Peng; Jin, Zhu; De La Cruz, Leydis; Kunzel, Carol; Marshall, Stephen E.; Metcalf, Sara S.

    2015-01-01

    Community-based programs are critical for locally targeted public health education and accessible service delivery. Deriving useful information from such programs is important for their own evaluation and improvement and may facilitate research collaboration with partners and experts. Here we present an interactive Web-based application designed for a community-based oral health outreach program called ElderSmile to demonstrate how data can be summarized, filtered, compared, and visualized by time and place to inform program planning, evaluation, and research. The ElderSmile TimeMap (http://www.acsu.buffalo.edu/∼smetcalf/resources/timemap.html) is an emergent product of a US National Institutes of Health–funded collaboration of knowledge sharing among multidisciplinary team members at the University at Buffalo, Columbia University, and New York University. PMID:26180989

  15. Map showing locations and statistical parameters of beach and offshore sand samples, Tutuila Island, American Samoa

    USGS Publications Warehouse

    Dingler, J.R.; Carlson, D.V.; Sallenger, A.H.

    1987-01-01

    In April 1985, sand samples were collected from many of the beaches on Tutuila Island, American Samoa, and in July 1985, three bays were surveyed using side-scan sonar and shallow seismic profiling. During that second trip, scuba divers collected sand samples from the surveyed areas. Dingler and others (1986) describes the study; this report presents the grain-size and composition data for the onshore and offshore sand samples. Locations of the onshore samples are plotted on the map of the island, which is reproduced from Normark and others (1985); locations of most of the offshore samples and side-scan sonar interpretations made during the study are plotted on enlargements (A and B, respectively) of Fagaitua and Nua-seetaga Bays. Lam Yuen (1981), U.S. Army Corps of Engineers (1980), and Sea Engineering Services Inc. (1980) provide additional information pertaining to the island's beaches.

  16. Research Update: Spatially resolved mapping of electronic structure on atomic level by multivariate statistical analysis

    DOE PAGES

    Belianinov, Alex; Panchapakesan, G.; Lin, Wenzhi; Sales, Brian C.; Sefat, Athena Safa; Jesse, Stephen; Pan, Minghu; Kalinin, Sergei V.

    2014-12-02

    Atomic level spatial variability of electronic structure in Fe-based superconductor FeTe0.55Se0.45 (Tc = 15 K) is explored using current-imaging tunneling-spectroscopy. Multivariate statistical analysis of the data differentiates regions of dissimilar electronic behavior that can be identified with the segregation of chalcogen atoms, as well as boundaries between terminations and near neighbor interactions. Subsequent clustering analysis allows identification of the spatial localization of these dissimilar regions. Similar statistical analysis of modeled calculated density of states of chemically inhomogeneous FeTe1 x Sex structures further confirms that the two types of chalcogens, i.e., Te and Se, can be identified by their electronic signaturemore » and differentiated by their local chemical environment. This approach allows detailed chemical discrimination of the scanning tunneling microscopy data including separation of atomic identities, proximity, and local configuration effects and can be universally applicable to chemically and electronically inhomogeneous surfaces.« less

  17. Research Update: Spatially resolved mapping of electronic structure on atomic level by multivariate statistical analysis

    SciTech Connect

    Belianinov, Alex Ganesh, Panchapakesan; Lin, Wenzhi; Jesse, Stephen; Pan, Minghu; Kalinin, Sergei V.; Sales, Brian C.; Sefat, Athena S.

    2014-12-01

    Atomic level spatial variability of electronic structure in Fe-based superconductor FeTe{sub 0.55}Se{sub 0.45} (T{sub c} = 15 K) is explored using current-imaging tunneling-spectroscopy. Multivariate statistical analysis of the data differentiates regions of dissimilar electronic behavior that can be identified with the segregation of chalcogen atoms, as well as boundaries between terminations and near neighbor interactions. Subsequent clustering analysis allows identification of the spatial localization of these dissimilar regions. Similar statistical analysis of modeled calculated density of states of chemically inhomogeneous FeTe{sub 1−x}Se{sub x} structures further confirms that the two types of chalcogens, i.e., Te and Se, can be identified by their electronic signature and differentiated by their local chemical environment. This approach allows detailed chemical discrimination of the scanning tunneling microscopy data including separation of atomic identities, proximity, and local configuration effects and can be universally applicable to chemically and electronically inhomogeneous surfaces.

  18. Gene-Environment Interactions Target Mitogen-activated Protein 3 Kinase 1 (MAP3K1) Signaling in Eyelid Morphogenesis*

    PubMed Central

    Mongan, Maureen; Meng, Qinghang; Wang, Jingjing; Kao, Winston W.-Y.; Puga, Alvaro; Xia, Ying

    2015-01-01

    Gene-environment interactions determine the biological outcomes through mechanisms that are poorly understood. Mouse embryonic eyelid closure is a well defined model to study the genetic control of developmental programs. Using this model, we investigated how exposure to dioxin-like environmental pollutants modifies the genetic risk of developmental abnormalities. Our studies reveal that mitogen-activated protein 3 kinase 1 (MAP3K1) signaling is a focal point of gene-environment cross-talk. Dioxin exposure, acting through the aryl hydrocarbon receptor (AHR), blocked eyelid closure in genetic mutants in which MAP3K1 signaling was attenuated but did not disturb this developmental program in either wild type or mutant mice with attenuated epidermal growth factor receptor or WNT signaling. Exposure also markedly inhibited c-Jun phosphorylation in Map3k1+/− embryonic eyelid epithelium, suggesting that dioxin-induced AHR pathways can synergize with gene mutations to inhibit MAP3K1 signaling. Our studies uncover a novel mechanism through which the dioxin-AHR axis interacts with the MAP3K1 signaling pathways during fetal development and provide strong empirical evidence that specific gene alterations can increase the risk of developmental abnormalities driven by environmental pollutant exposure. PMID:26109068

  19. A spatial, statistical approach to map the risk of milk contamination by β-hexachlorocyclohexane in dairy farms.

    PubMed

    Battisti, Sabrina; Caminiti, Antonino; Ciotoli, Giancarlo; Panetta, Valentina; Rombolà, Pasquale; Sala, Marcello; Ubaldi, Alessandro; Scaramozzino, Paola

    2013-11-01

    In May 2005, beta-hexachlorocyclohexane (β-HCH) was found in a sample of bovine bulk milk from a farm in the Sacco River valley (Latium region, central Italy). The primary source of contamination was suspected to be industrial discharge into the environment with the Sacco River as the main mean of dispersion. Since then, a surveillance programme on bulk milk of the local farms was carried out by the veterinary services. In order to estimate the spatial probability of β- HCH contamination of milk produced in the Sacco River valley and draw probability maps of contamination, probability maps of β-HCH values in milk were estimated by indicator kriging (IK), a geo-statistical estimator, and traditional logistic regression (LR) combined with a geographical information systems approach. The former technique produces a spatial view of probabilities above a specific threshold at non-sampled locations on the basis of observed values in the area, while LR gives the probabilities in specific locations on the basis of certain environmental predictors, namely the distance from the river, the distance from the pollution site, the elevation above the river level and the intrinsic vulnerability of hydro-geological formations. Based on the β-HCH data from 2005 in the Sacco River valley, the two techniques resulted in similar maps of high risk of milk contamination. However, unlike the IK method, the LR model was capable of estimating coefficients that could be used in case of future pollution episodes. The approach presented produces probability maps and define high-risk areas already in the early stages of an emergency before sampling operations have been carried out.

  20. A method for modelling peak signal statistics on a mobile satellite transponder

    NASA Technical Reports Server (NTRS)

    Bilodeau, Andre; Lecours, Michel; Pelletier, Marcel; Delisle, Gilles Y.

    1990-01-01

    A simulation method is proposed. The simulation was developed to model the peak duration and energy content of signal peaks in a mobile communication satellite operating in a Frequency Division Multiple Access (FDMA) mode and presents an estimate of those power peaks for a system where the channels are modeled as band limited Gaussian noise, which is taken as a reasonable representation for Amplitude Commanded Single Sideband (ACSSB), Minimum Shift Keying (MSK), or Phase Shift Keying (PSK) modulated signals. The simulation results show that, under this hypothesis, the level of the signal power peaks for 10 percent, 1 percent, and 0.1 percent of the time are well described by a Rayleigh law and that their duration is extremely short and inversely proportional to the total FDM system bandwidth.

  1. Probabilistic storm surge inundation maps for Metro Manila based on Philippine public storm warning signals

    NASA Astrophysics Data System (ADS)

    Tablazon, J.; Caro, C. V.; Lagmay, A. M. F.; Briones, J. B. L.; Dasallas, L.; Lapidez, J. P.; Santiago, J.; Suarez, J. K.; Ladiero, C.; Gonzalo, L. A.; Mungcal, M. T. F.; Malano, V.

    2015-03-01

    A storm surge is the sudden rise of sea water over the astronomical tides, generated by an approaching storm. This event poses a major threat to the Philippine coastal areas, as manifested by Typhoon Haiyan on 8 November 2013. This hydro-meteorological hazard is one of the main reasons for the high number of casualties due to the typhoon, with 6300 deaths. It became evident that the need to develop a storm surge inundation map is of utmost importance. To develop these maps, the Nationwide Operational Assessment of Hazards under the Department of Science and Technology (DOST-Project NOAH) simulated historical tropical cyclones that entered the Philippine Area of Responsibility. The Japan Meteorological Agency storm surge model was used to simulate storm surge heights. The frequency distribution of the maximum storm surge heights was calculated using simulation results of tropical cyclones under a specific public storm warning signal (PSWS) that passed through a particular coastal area. This determines the storm surge height corresponding to a given probability of occurrence. The storm surge heights from the model were added to the maximum astronomical tide data from WXTide software. The team then created maps of inundation for a specific PSWS using the probability of exceedance derived from the frequency distribution. Buildings and other structures were assigned a probability of exceedance depending on their occupancy category, i.e., 1% probability of exceedance for critical facilities, 10% probability of exceedance for special occupancy structures, and 25% for standard occupancy and miscellaneous structures. The maps produced show the storm-surge-vulnerable areas in Metro Manila, illustrated by the flood depth of up to 4 m and extent of up to 6.5 km from the coastline. This information can help local government units in developing early warning systems, disaster preparedness and mitigation plans, vulnerability assessments, risk-sensitive land use plans, shoreline

  2. Ex Vivo Signaling Protein Mapping in T Lymphocytes in the Psoriatic Arthritis Joints.

    PubMed

    Fiocco, Ugo; Martini, Veronica; Accordi, Benedetta; Caso, Francesco; Costa, Luisa; Oliviero, Francesca; Scanu, Anna; Felicetti, Mara; Frallonardo, Paola; Facco, Monica; Boso, Daniele; Molena, Beatrice; Zambello, Renato; Ramonda, Roberta; Cozzi, Franco; Scarpa, Raffaele; Basso, Giuseppe; Semenzato, Gianpietro; Dayer, Jean-Michel; Doria, Andrea; Punzi, Leonardo

    2015-11-01

    We assessed signaling protein mapping in total T cells, to analyze the proportions of T regulatory (Treg) and TCD4+ effector (Teff) cell phenotypes, and the respective interleukin 6Rα (IL-6Rα) expression in the inflammatory microenvironment of synovial fluid (SF) of patients with sustained psoriatic arthritis (PsA). Our approach was to measure the IL-6 level in SF using a multiplex bead immunoassay. Reverse-phase protein array was used to assess Janus kinase (JAK) 1 and JAK2, extra-cellular regulated kinase (ERK) 1 and 2, protein kinase Cδ (PKCδ), signal transducer and activator and transcription (STAT) 1, STAT3, and STAT5 phosphoproteins in total T cell lysates from SF of patients with PsA. Frequencies of CD4+IL-17A-F+IL-23+ CD4+ Th cells producing IL-17A and IL-17F (Th17) and CD4+CD25high intracellular forkhead box transcription factor+ (FOXP3+) phenotypes, and the percentage of Treg- and Teff- cells were quantified in SF and matched peripheral blood (PB) of patients with PsA and PB of healthy controls (HC) by flow cytometry. Our results were the following: In PsA SF samples, a coordinate increase of JAK1, ERK1/2, STAT1, STAT3, and STAT5 phosphoproteins was found in total T cells in SF of PsA; where IL-6 levels were higher than in PB from HC. Expanded CD4+IL-17A-F+IL-23+ Th17, CD4+ CD25- Teff- and CD4+CD25(high) FoxP3+Treg subsets, showing similar levels of enhanced IL-6Rδ expression, were confined to PsA joints. In our studies, the transcriptional network profile identified by ex vivo signaling protein mapping in T lymphocytes in PsA joints revealed the complex interplay between IL-1, IL-6, and IL-23 signaling and differentiation of Th17 cells and CD4+Tregs in sustained joint inflammation in PsA. PMID:26523057

  3. Image informative maps for component-wise estimating parameters of signal-dependent noise

    NASA Astrophysics Data System (ADS)

    Uss, Mykhail L.; Vozel, Benoit; Lukin, Vladimir V.; Chehdi, Kacem

    2013-01-01

    We deal with the problem of blind parameter estimation of signal-dependent noise from mono-component image data. Multispectral or color images can be processed in a component-wise manner. The main results obtained rest on the assumption that the image texture and noise parameters estimation problems are interdependent. A two-dimensional fractal Brownian motion (fBm) model is used for locally describing image texture. A polynomial model is assumed for the purpose of describing the signal-dependent noise variance dependence on image intensity. Using the maximum likelihood approach, estimates of both fBm-model and noise parameters are obtained. It is demonstrated that Fisher information (FI) on noise parameters contained in an image is distributed nonuniformly over intensity coordinates (an image intensity range). It is also shown how to find the most informative intensities and the corresponding image areas for a given noisy image. The proposed estimator benefits from these detected areas to improve the estimation accuracy of signal-dependent noise parameters. Finally, the potential estimation accuracy (Cramér-Rao Lower Bound, or CRLB) of noise parameters is derived, providing confidence intervals of these estimates for a given image. In the experiment, the proposed and existing state-of-the-art noise variance estimators are compared for a large image database using CRLB-based statistical efficiency criteria.

  4. MAP kinases with distinct inhibitory functions impart signaling specificity during yeast differentiation.

    PubMed

    Madhani, H D; Styles, C A; Fink, G R

    1997-11-28

    Filamentous invasive growth of S. cerevisiae requires multiple elements of the mitogen-activated protein kinase (MAPK) signaling cascade that are also components of the mating pheromone response pathway. Here we show that, despite sharing several constituents, the two pathways use different MAP kinases. The Fus3 MAPK regulates mating, whereas the Kss1 MAPK regulates filamentation and invasion. Remarkably, in addition to their kinase-dependent activation functions, Kss1 and Fus3 each have a distinct kinase-independent inhibitory function. Kss1 inhibits the filamentation pathway by interacting with its target transcription factor Ste12. Fus3 has a different inhibitory activity that prevents the inappropriate activation of invasion by the pheromone response pathway. In the absence of Fus3, there is erroneous crosstalk in which mating pheromone now activates filamentation-specific gene expression using the Kss1 MAPK. PMID:9393860

  5. A Self-Organizing Map-Based Approach to Generating Reduced-Size, Statistically Similar Climate Datasets

    NASA Astrophysics Data System (ADS)

    Cabell, R.; Delle Monache, L.; Alessandrini, S.; Rodriguez, L.

    2015-12-01

    Climate-based studies require large amounts of data in order to produce accurate and reliable results. Many of these studies have used 30-plus year data sets in order to produce stable and high-quality results, and as a result, many such data sets are available, generally in the form of global reanalyses. While the analysis of these data lead to high-fidelity results, its processing can be very computationally expensive. This computational burden prevents the utilization of these data sets for certain applications, e.g., when rapid response is needed in crisis management and disaster planning scenarios resulting from release of toxic material in the atmosphere. We have developed a methodology to reduce large climate datasets to more manageable sizes while retaining statistically similar results when used to produce ensembles of possible outcomes. We do this by employing a Self-Organizing Map (SOM) algorithm to analyze general patterns of meteorological fields over a regional domain of interest to produce a small set of "typical days" with which to generate the model ensemble. The SOM algorithm takes as input a set of vectors and generates a 2D map of representative vectors deemed most similar to the input set and to each other. Input predictors are selected that are correlated with the model output, which in our case is an Atmospheric Transport and Dispersion (T&D) model that is highly dependent on surface winds and boundary layer depth. To choose a subset of "typical days," each input day is assigned to its closest SOM map node vector and then ranked by distance. Each node vector is treated as a distribution and days are sampled from them by percentile. Using a 30-node SOM, with sampling every 20th percentile, we have been able to reduce 30 years of the Climate Forecast System Reanalysis (CFSR) data for the month of October to 150 "typical days." To estimate the skill of this approach, the "Measure of Effectiveness" (MOE) metric is used to compare area and overlap

  6. A Critical Examination of the Statistic Used for Processing Speech Signals.

    ERIC Educational Resources Information Center

    Knox, Keith

    This paper assesses certain properties of human mental processes by focusing on the tactics utilized in perceiving speech signals. Topics discussed in the paper include the power spectrum approach to fluctuations and noise, with particular reference to biological structures; "l/f-like" fluctuations in speech and music and the functioning of a…

  7. TU-C-12A-02: Development of a Multiparametric Statistical Response Map for Quantitative Imaging

    SciTech Connect

    Bosca, R; Mahajan, A; Brown, PD; Stafford, RJ; Johnson, VE; Dong, L; Jackson, EF

    2014-06-15

    Purpose: Quantitative imaging biomarkers (QIB) are becoming increasingly utilized in early phase clinical trials as a means of non-invasively assessing treatment response and associated response heterogeneity. The aim of this study was to develop a flexible multiparametric statistical framework to predict voxel-by-voxel response of several potential MRI QIBs. Methods: Patients with histologically proven glioblastomas (n=11) were treated with chemoradiation (with/without bevacizumab) and underwent one baseline and two mid-treatment (3–4wks) MRIs. Dynamic contrast-enhanced (3D FSPGR, 6.3sec/phase, 0.1 mmol/kg Gd-DTPA), dynamic susceptibility contrast (2D GRE-EPI, 1.5sec/phase, 0.2mmol/kg Gd-DTPA), and diffusion tensor (2D DW-EPI, b=0, 1200 s/mm{sup 2}, 27 directions) imaging acquisitions were obtained during each study. Mid-treatment and pre-treatment images were rigidly aligned, and regions of partial response (PR), stable disease (SD), and progressive disease (PD) were contoured in consensus by two experienced radiation oncologists. Voxels in these categories were used to train ordinal (PRstatistical framework for incorporating longitudinal multiparametric

  8. Distinguishing transient signals and instrumental disturbances in semi-coherent searches for continuous gravitational waves with line-robust statistics

    NASA Astrophysics Data System (ADS)

    Keitel, David

    2016-05-01

    Non-axisymmetries in rotating neutron stars emit quasi-monochromatic gravitational waves. These long-duration ‘continuous wave’ signals are among the main search targets of ground-based interferometric detectors. However, standard detection methods are susceptible to false alarms from instrumental artefacts that resemble a continuous-wave signal. Past work [Keitel, Prix, Papa, Leaci and Siddiqi 2014, Phys. Rev. D 89 064023] showed that a Bayesian approach, based on an explicit model of persistent single-detector disturbances, improves robustness against such artefacts. Since many strong outliers in semi-coherent searches of LIGO data are caused by transient disturbances that last only a few hours or days, I describe in a recent paper [Keitel D 2015, LIGO-P1500159] how to extend this approach to cover transient disturbances, and demonstrate increased sensitivity in realistic simulated data. Additionally, neutron stars could emit transient signals which, for a limited time, also follow the continuous-wave signal model. As a pragmatic alternative to specialized transient searches, I demonstrate how to make standard semi-coherent continuous-wave searches more sensitive to transient signals. Focusing on the time-scale of a single segment in the semi-coherent search, Bayesian model selection yields a simple detection statistic without a significant increase in computational cost. This proceedings contribution gives a brief overview of both works.

  9. DENDROCLIM2002: A C++ program for statistical calibration of climate signals in tree-ring chronologies

    NASA Astrophysics Data System (ADS)

    Biondi, Franco; Waikul, Kishor

    2004-04-01

    Tree-ring chronologies are often calibrated against instrumental climate records using correlation and response functions. DENDROCLIM2002 uses bootstrapped confidence intervals to estimate the significance of both correlation and response function coefficients. Input and output file selection, as well as analytical options, are chosen from a user-friendly GUI. Final results are saved in ASCII format, and are plotted on screen using color-coded symbols. DENDROCLIM2002 is an extension of existing task-specific software, which is mostly MS-DOS based, and of available user-supplied code for statistical packages, such as SAS. In addition, DENDROCLIM2002 incorporates the ability to test for temporal changes of dendroclimatic relationships by means of evolutionary and moving intervals. This simple approach allows for a complete, dynamical representation of statistical relationships between climate and tree growth. An example using published dendroclimatic data is used to illustrate the analytical and graphical capabilities of the software.

  10. A statistical-topographic model for mapping climatological precipitation over mountainous terrain

    SciTech Connect

    Daly, C.; Neilson, R.P.; Phillips, D.L.

    1994-02-01

    The demand for climatological precipitation fields on a regular grid is growing dramatically as ecological and hydrological models become increasingly linked to geographic information systems that spatially represent and manipulate model output. This paper presents an analytical model that distributes point measurements of monthly and annual precipitation to regularly spaced grid cells in midlatitude regions. PRISM (Precipitation-elevation Regressions on Independent Slopes Model) brings a combination of climatological and statistical concepts to the analysis of orographic precipitation. Specifically, PRISM (1) uses a digital elevation model (DEM) to estimate the {open_quotes}orographic{close_quotes} elevations of precipitation stations; (2) uses the DEM and a windowing technique to group stations onto individual topographic facets; (3) estimates precipitation at a DEM grid cell through a regression of precipitation versus DEM elevation developed from stations on the cell`s topographic facet; and (4) when possible, calculates a prediction interval for the estimate, which is an approximation of the uncertainty involved. PRISM exhibited the lowest cross-validation bias and absolute error when compared to kriging, detrended kriging, and cokriging in the Willamette River basin, Oregon. PRISM was also applied to northern Oregon and to the entire western United States; detrended kriging and cokriging could not be used, because there was no overall relationship between elevation and precipitation. Cross-validation errors in these applications were confined to relatively low levels because PRISM continually adjusts its frame of reference by using localized precipitation-DEM elevation relationships. 39 refs., 9 figs., 5 tabs.

  11. Mapping Individual Brain Networks Using Statistical Similarity in Regional Morphology from MRI

    PubMed Central

    Kong, Xiang-zhen; Liu, Zhaoguo; Huang, Lijie; Wang, Xu; Yang, Zetian; Zhou, Guangfu; Zhen, Zonglei; Liu, Jia

    2015-01-01

    Representing brain morphology as a network has the advantage that the regional morphology of ‘isolated’ structures can be described statistically based on graph theory. However, very few studies have investigated brain morphology from the holistic perspective of complex networks, particularly in individual brains. We proposed a new network framework for individual brain morphology. Technically, in the new network, nodes are defined as regions based on a brain atlas, and edges are estimated using our newly-developed inter-regional relation measure based on regional morphological distributions. This implementation allows nodes in the brain network to be functionally/anatomically homogeneous but different with respect to shape and size. We first demonstrated the new network framework in a healthy sample. Thereafter, we studied the graph-theoretical properties of the networks obtained and compared the results with previous morphological, anatomical, and functional networks. The robustness of the method was assessed via measurement of the reliability of the network metrics using a test-retest dataset. Finally, to illustrate potential applications, the networks were used to measure age-related changes in commonly used network metrics. Results suggest that the proposed method could provide a concise description of brain organization at a network level and be used to investigate interindividual variability in brain morphology from the perspective of complex networks. Furthermore, the method could open a new window into modeling the complexly distributed brain and facilitate the emerging field of human connectomics. PMID:26536598

  12. Irisin promotes osteoblast proliferation and differentiation via activating the MAP kinase signaling pathways.

    PubMed

    Qiao, Xiaoyong; Yong Qiao, Xiao; Nie, Ying; Ma, Yaxian; Xian Ma, Ya; Chen, Yan; Cheng, Ran; Yin, Weiyao; Yao Yinrg, Wei; Hu, Ying; Xu, Wenming; Ming Xu, Wen; Xu, Liangzhi; Zhi Xu, Liang

    2016-01-07

    Physical exercise is able to improve skeletal health. However, the mechanisms are poorly known. Irisin, a novel exercise-induced myokine, secreted by skeletal muscle in response to exercise, have been shown to mediate beneficial effects of exercise in many disorders. In the current study, we demonstrated that irisin promotes osteoblast proliferation, and increases the expression of osteoblastic transcription regulators, such as Runt-related transcription factor-2, osterix/sp7; and osteoblast differentiation markers, including alkaline phosphatase, collagen type 1 alpha-1, osteocalcin, and osteopontin in vitro. Irisin also increase ALP activity and calcium deposition in cultured osteoblast. These osteogenic effects were mediated by activating the p38 mitogen-activated protein kinase (p-p38 MAPK) and extracellular signal-regulated kinase (ERK). Inhibition of p38 MAPK by SB023580 or pERK by U0126 abolished the proliferation and up-regulatory effects of irisin on Runx2 expression and ALP activity. Together our observation suggest that irisin directly targets osteoblast, promoting osteoblast proliferation and differentiation via activating P38/ERK MAP kinase signaling cascades in vitro. Whether irisin can be utilized as the therapeutic agents for osteopenia and osteoporosis is worth to be further pursued.

  13. Irisin promotes osteoblast proliferation and differentiation via activating the MAP kinase signaling pathways

    PubMed Central

    Yong Qiao, Xiao; Nie, Ying; Xian Ma, Ya; Chen, Yan; Cheng, Ran; Yao Yinrg, Wei; Hu, Ying; Ming Xu, Wen; Zhi Xu, Liang

    2016-01-01

    Physical exercise is able to improve skeletal health. However, the mechanisms are poorly known. Irisin, a novel exercise-induced myokine, secreted by skeletal muscle in response to exercise, have been shown to mediate beneficial effects of exercise in many disorders. In the current study, we demonstrated that irisin promotes osteoblast proliferation, and increases the expression of osteoblastic transcription regulators, such as Runt-related transcription factor-2, osterix/sp7; and osteoblast differentiation markers, including alkaline phosphatase, collagen type 1 alpha-1, osteocalcin, and osteopontin in vitro. Irisin also increase ALP activity and calcium deposition in cultured osteoblast. These osteogenic effects were mediated by activating the p38 mitogen-activated protein kinase (p-p38 MAPK) and extracellular signal-regulated kinase (ERK). Inhibition of p38 MAPK by SB023580 or pERK by U0126 abolished the proliferation and up-regulatory effects of irisin on Runx2 expression and ALP activity. Together our observation suggest that irisin directly targets osteoblast, promoting osteoblast proliferation and differentiation via activating P38/ERK MAP kinase signaling cascades in vitro. Whether irisin can be utilized as the therapeutic agents for osteopenia and osteoporosis is worth to be further pursued. PMID:26738434

  14. Real time moving object detection using motor signal and depth map for robot car

    NASA Astrophysics Data System (ADS)

    Wu, Hao; Siu, Wan-Chi

    2013-12-01

    Moving object detection from a moving camera is a fundamental task in many applications. For the moving robot car vision, the background movement is 3D motion structure in nature. In this situation, the conventional moving object detection algorithm cannot be use to handle the 3D background modeling effectively and efficiently. In this paper, a novel scheme is proposed by utilizing the motor control signal and depth map obtained from a stereo camera to model the perspective transform matrix between different frames under a moving camera. In our approach, the coordinate relationship between frames during camera moving is modeled by a perspective transform matrix which is obtained by using current motor control signals and the pixel depth value. Hence, the relationship between a static background pixel and the moving foreground corresponding to the camera motion can be related by a perspective matrix. To enhance the robustness of classification, we allowed a tolerance range during the perspective transform matrix prediction and used multi-reference frames to classify the pixel on current frame. The proposed scheme has been found to be able to detect moving objects for our moving robot car efficiently. Different from conventional approaches, our method can model the moving background in 3D structure, without online model training. More importantly, the computational complexity and memory requirement are low making it possible to implement this scheme in real-time, which is even valuable for a robot vision system.

  15. Mapping.

    ERIC Educational Resources Information Center

    Kinney, Douglas M.; McIntosh, Willard L.

    1979-01-01

    The area of geological mapping in the United States in 1978 increased greatly over that reported in 1977; state geological maps were added for California, Idaho, Nevada, and Alaska last year. (Author/BB)

  16. Statistical parametric mapping and cluster counting analysis of [18F] FDG-PET imaging in traumatic brain injury.

    PubMed

    Zhang, Jing; Mitsis, Effie M; Chu, Kingwai; Newmark, Randall E; Hazlett, Erin A; Buchsbaum, Monte S

    2010-01-01

    In this study we investigated regional cerebral glucose metabolism abnormalities of [(18)F] fluorodeoxyglucose (FDG) positron emission tomography (PET) imaging in traumatic brain injury (TBI). PET images of 81 TBI patients and 68 normal controls were acquired and a word list learning task was administered during the uptake period. The TBI group included 35 patients with positive structural imaging (CT or MRI) findings soon after injury, 40 patients with negative findings, and 6 cases without structural imaging. Statistical parametric mapping (SPM) analysis was applied with several levels of spatial smoothing. Cluster counting analysis was performed for each subject to identify abnormal clusters with contiguous voxel values that deviated by two standard deviations or more from the mean of the normal controls, and to count the number of clusters in 10 size categories. SPM maps demonstrated that the 81 patients had significantly lower FDG uptake than normal controls, widely across the cortex (including bilateral frontal and temporal regions), and in the thalamus. Cluster counting results indicated that TBI patients had a higher proportion of larger clusters than controls. These large low-FDG-uptake clusters of the TBI patients were closer to the brain edge than those of controls. These results suggest that deficits of cerebral metabolism in TBI are spread over multiple brain areas, that they are closer to the cortical surface than clusters in controls, and that group spatial patterns of abnormal cerebral metabolism may be similar in TBI patients with cognitive deficits with and without obvious acute abnormalities identified on structural imaging.

  17. Mapping cell populations in flow cytometry data for cross-sample comparison using the Friedman-Rafsky test statistic as a distance measure.

    PubMed

    Hsiao, Chiaowen; Liu, Mengya; Stanton, Rick; McGee, Monnie; Qian, Yu; Scheuermann, Richard H

    2016-01-01

    Flow cytometry (FCM) is a fluorescence-based single-cell experimental technology that is routinely applied in biomedical research for identifying cellular biomarkers of normal physiological responses and abnormal disease states. While many computational methods have been developed that focus on identifying cell populations in individual FCM samples, very few have addressed how the identified cell populations can be matched across samples for comparative analysis. This article presents FlowMap-FR, a novel method for cell population mapping across FCM samples. FlowMap-FR is based on the Friedman-Rafsky nonparametric test statistic (FR statistic), which quantifies the equivalence of multivariate distributions. As applied to FCM data by FlowMap-FR, the FR statistic objectively quantifies the similarity between cell populations based on the shapes, sizes, and positions of fluorescence data distributions in the multidimensional feature space. To test and evaluate the performance of FlowMap-FR, we simulated the kinds of biological and technical sample variations that are commonly observed in FCM data. The results show that FlowMap-FR is able to effectively identify equivalent cell populations between samples under scenarios of proportion differences and modest position shifts. As a statistical test, FlowMap-FR can be used to determine whether the expression of a cellular marker is statistically different between two cell populations, suggesting candidates for new cellular phenotypes by providing an objective statistical measure. In addition, FlowMap-FR can indicate situations in which inappropriate splitting or merging of cell populations has occurred during gating procedures. We compared the FR statistic with the symmetric version of Kullback-Leibler divergence measure used in a previous population matching method with both simulated and real data. The FR statistic outperforms the symmetric version of KL-distance in distinguishing equivalent from nonequivalent cell

  18. Statistical ensemble analysis for simulating extrinsic noise-driven response in NF-κB signaling networks

    PubMed Central

    2013-01-01

    Background Gene expression profiles and protein dynamics in single cells have a large cell-to-cell variability due to intracellular noise. Intracellular fluctuations originate from two sources: intrinsic noise due to the probabilistic nature of biochemical reactions and extrinsic noise due to randomized interactions of the cell with other cellular systems or its environment. Presently, there is no systematic parameterization and modeling scheme to simulate cellular response at the single cell level in the presence of extrinsic noise. Results In this paper, we propose a novel statistical ensemble method to simulate the distribution of heterogeneous cellular responses in single cells. We capture the effects of extrinsic noise by randomizing values of the model parameters. In this context, a statistical ensemble is a large number of system replicates, each with randomly sampled model parameters from biologically feasible intervals. We apply this statistical ensemble approach to the well-studied NF-κB signaling system. We predict several characteristic dynamic features of NF-κB response distributions; one of them is the dosage-dependent distribution of the first translocation time of NF-κB. Conclusion The distributions of heterogeneous cellular responses that our statistical ensemble formulation generates reveal the effect of different cellular conditions, e.g., effects due to wild type versus mutant cells or between different dosages of external stimulants. Distributions generated in the presence of extrinsic noise yield valuable insight into underlying regulatory mechanisms, which are sometimes otherwise hidden. PMID:23742268

  19. Atlas of Cancer Signalling Network: a systems biology resource for integrative analysis of cancer data with Google Maps

    PubMed Central

    Kuperstein, I; Bonnet, E; Nguyen, H-A; Cohen, D; Viara, E; Grieco, L; Fourquet, S; Calzone, L; Russo, C; Kondratova, M; Dutreix, M; Barillot, E; Zinovyev, A

    2015-01-01

    Cancerogenesis is driven by mutations leading to aberrant functioning of a complex network of molecular interactions and simultaneously affecting multiple cellular functions. Therefore, the successful application of bioinformatics and systems biology methods for analysis of high-throughput data in cancer research heavily depends on availability of global and detailed reconstructions of signalling networks amenable for computational analysis. We present here the Atlas of Cancer Signalling Network (ACSN), an interactive and comprehensive map of molecular mechanisms implicated in cancer. The resource includes tools for map navigation, visualization and analysis of molecular data in the context of signalling network maps. Constructing and updating ACSN involves careful manual curation of molecular biology literature and participation of experts in the corresponding fields. The cancer-oriented content of ACSN is completely original and covers major mechanisms involved in cancer progression, including DNA repair, cell survival, apoptosis, cell cycle, EMT and cell motility. Cell signalling mechanisms are depicted in detail, together creating a seamless ‘geographic-like' map of molecular interactions frequently deregulated in cancer. The map is browsable using NaviCell web interface using the Google Maps engine and semantic zooming principle. The associated web-blog provides a forum for commenting and curating the ACSN content. ACSN allows uploading heterogeneous omics data from users on top of the maps for visualization and performing functional analyses. We suggest several scenarios for ACSN application in cancer research, particularly for visualizing high-throughput data, starting from small interfering RNA-based screening results or mutation frequencies to innovative ways of exploring transcriptomes and phosphoproteomes. Integration and analysis of these data in the context of ACSN may help interpret their biological significance and formulate mechanistic hypotheses

  20. Atlas of Cancer Signalling Network: a systems biology resource for integrative analysis of cancer data with Google Maps.

    PubMed

    Kuperstein, I; Bonnet, E; Nguyen, H-A; Cohen, D; Viara, E; Grieco, L; Fourquet, S; Calzone, L; Russo, C; Kondratova, M; Dutreix, M; Barillot, E; Zinovyev, A

    2015-01-01

    Cancerogenesis is driven by mutations leading to aberrant functioning of a complex network of molecular interactions and simultaneously affecting multiple cellular functions. Therefore, the successful application of bioinformatics and systems biology methods for analysis of high-throughput data in cancer research heavily depends on availability of global and detailed reconstructions of signalling networks amenable for computational analysis. We present here the Atlas of Cancer Signalling Network (ACSN), an interactive and comprehensive map of molecular mechanisms implicated in cancer. The resource includes tools for map navigation, visualization and analysis of molecular data in the context of signalling network maps. Constructing and updating ACSN involves careful manual curation of molecular biology literature and participation of experts in the corresponding fields. The cancer-oriented content of ACSN is completely original and covers major mechanisms involved in cancer progression, including DNA repair, cell survival, apoptosis, cell cycle, EMT and cell motility. Cell signalling mechanisms are depicted in detail, together creating a seamless 'geographic-like' map of molecular interactions frequently deregulated in cancer. The map is browsable using NaviCell web interface using the Google Maps engine and semantic zooming principle. The associated web-blog provides a forum for commenting and curating the ACSN content. ACSN allows uploading heterogeneous omics data from users on top of the maps for visualization and performing functional analyses. We suggest several scenarios for ACSN application in cancer research, particularly for visualizing high-throughput data, starting from small interfering RNA-based screening results or mutation frequencies to innovative ways of exploring transcriptomes and phosphoproteomes. Integration and analysis of these data in the context of ACSN may help interpret their biological significance and formulate mechanistic hypotheses

  1. A Bootstrap Method for Statistical Power System Mode Estimation and Probing Signal Selection

    SciTech Connect

    Zhou, Ning; Pierre, John W; Trudnowski, Daniel

    2006-06-30

    Near real-time measurement-based electromechanical-mode estimation offers considerable potential for many future power-system operation and control strategies. Recent research has investigated the use of low-level Pseudo Random Noise (PRN) probing signals injected into power systems to estimate the low-frequency electromechanical modes. Because of the random na-ture of a power system, estimating the modes from a single prob-ing experiment is very difficult. Ideally, one would use a Monte-Carlo approach with multiple independent probing experiments resulting in a mode estimation distribution. Then, one could state that the mode is within a region of the complex plane. Unfortu-nately, conducting multiple probing experiments is prohibitive for most power-system applications. This paper presents a method-ology for estimating the mode distribution based on one probing test using a Bootstrap algorithm. The proposed method is applied to both simulation data and actual-system measurement data to illustrate its performance and application. It is demonstrated that the method can provide valuable information to PRN tests and guide future PRN probing signal design and selection.

  2. The influrence of an optical receiving system on statistical characteristics of a lidar signal

    NASA Technical Reports Server (NTRS)

    Zuev, A. E.; Banakh, V. A.; Mironov, V. L.

    1986-01-01

    The effects connected with correlation of direct and backward waves propagating through the same randomly inhomogeneous media can be observed along the path with refection in a turbulent atmosphere. In particular, the mean intensity of the reflected wave can increase in comparison with the wave propagating in the forward direction at a doubled distance; the intensity fluctuations can become stronger. These effects depend on the strength of optical turbulence, as well as on the diffraction sizes of the exit apertures of the source and the reflector. However, the focusing of radiation reflected with a receiving telescope leads, in some cases, to the fact that the dependence of amplification effects on the parameters becomes essentially different. This should be taken into account when alayzing the lidar signals. The effect of backscattering amplification and amplification of the intensity fluctuations is discussed.

  3. Robust classification of motor imagery EEG signals using statistical time-domain features.

    PubMed

    Khorshidtalab, A; Salami, M J E; Hamedi, M

    2013-11-01

    The tradeoff between computational complexity and speed, in addition to growing demands for real-time BMI (brain-machine interface) systems, expose the necessity of applying methods with least possible complexity. Willison amplitude (WAMP) and slope sign change (SSC) are two promising time-domain features only if the right threshold value is defined for them. To overcome the drawback of going through trial and error for the determination of a suitable threshold value, modified WAMP and modified SSC are proposed in this paper. Besides, a comprehensive assessment of statistical time-domain features in which their effectiveness is evaluated with a support vector machine (SVM) is presented. To ensure the accuracy of the results obtained by the SVM, the performance of each feature is reassessed with supervised fuzzy C-means. The general assessment shows that every subject had at least one of his performances near or greater than 80%. The obtained results prove that for BMI applications, in which a few errors can be tolerated, these combinations of feature-classifier are suitable. Moreover, features that could perform satisfactorily were selected for feature combination. Combinations of the selected features are evaluated with the SVM, and they could significantly improve the results, in some cases, up to full accuracy. PMID:24152422

  4. Context Specificity of Stress-activated Mitogen-activated Protein (MAP) Kinase Signaling: The Story as Told by Caenorhabditis elegans.

    PubMed

    Andrusiak, Matthew G; Jin, Yishi

    2016-04-01

    Stress-associated p38 and JNK mitogen-activated protein (MAP) kinase signaling cascades trigger specific cellular responses and are involved in multiple disease states. At the root of MAP kinase signaling complexity is the differential use of common components on a context-specific basis. The roundwormCaenorhabditis eleganswas developed as a system to study genes required for development and nervous system function. The powerful genetics ofC. elegansin combination with molecular and cellular dissections has led to a greater understanding of how p38 and JNK signaling affects many biological processes under normal and stress conditions. This review focuses on the studies revealing context specificity of different stress-activated MAPK components inC. elegans.

  5. Context Specificity of Stress-activated Mitogen-activated Protein (MAP) Kinase Signaling: The Story as Told by Caenorhabditis elegans.

    PubMed

    Andrusiak, Matthew G; Jin, Yishi

    2016-04-01

    Stress-associated p38 and JNK mitogen-activated protein (MAP) kinase signaling cascades trigger specific cellular responses and are involved in multiple disease states. At the root of MAP kinase signaling complexity is the differential use of common components on a context-specific basis. The roundwormCaenorhabditis eleganswas developed as a system to study genes required for development and nervous system function. The powerful genetics ofC. elegansin combination with molecular and cellular dissections has led to a greater understanding of how p38 and JNK signaling affects many biological processes under normal and stress conditions. This review focuses on the studies revealing context specificity of different stress-activated MAPK components inC. elegans. PMID:26907690

  6. Spatio-temporal mapping and modeling of a new forest disease spread using remote sensing and spatial statistics

    NASA Astrophysics Data System (ADS)

    Liu, Desheng

    In central coastal California, a recently discovered pathogen Phytophthora ramorum has been killing hundreds of thousands of tanoak, coast live oak, and black oak trees. This forest disease referred to as Sudden Oak Death (SOD) has attracted attention from the public, government and academia. Monitoring the disease distribution and understanding the disease mechanisms are important for disease control and management. In this dissertation, I developed a spatio-temporal approach to mapping and modeling the SOD spread in California using remote sensing and spatial statistics. This dissertation seeks to quantify the disease spread over a range of scales using multi-temporal high spatial resolution airborne imagery. The work has three components: multi-temporal image registration, spatio-temporal classification, and spatial pattern analysis of disease dynamics. First, I developed an automated algorithm to register multi-temporal airborne images, which are characterized by complex geometric distortion with respect to one another. In this algorithm, large amounts of evenly distributed control points on regular grids were first derived from area-based methods. The control points with outliers removed were then applied to local transformation models. The results showed that the combination of area-based control point extraction with local transformation models is successful for geometric registration of airborne images with complex local distortion. Second, I developed a spatio-temporal classification algorithm to map mortality patterns from the accurately co-registered multi-temporal images. This algorithm is based on Markov Random Fields and Support Vector Machines and explicitly integrates spectral, spatial and temporal information in multi-temporal high-spatial resolution images. The results indicated that the algorithm achieved significant improvements over non-contextual classifications. Third, I applied both univariate and multivariate spatial point pattern analysis

  7. Regional patterns of cropland and pasture burning: Statistical separation of signals from remote sensing products

    NASA Astrophysics Data System (ADS)

    Rabin, S. S.; Pacala, S. W.; Magi, B. I.; Shevliakova, E.

    2013-12-01

    The use of fire in agriculture--to manage crop residues and pastoral grasses, and for clearing land--has consequences worldwide for air quality, human health, and climate. Airborne particulate matter from such burning aggravates respiratory ailments and can influence regional precipitation, while associated greenhouse gases and aerosols affect global climate. Little research, however, has focused on understanding patterns of cropland and pasture fire use with an eye towards simulation at global scales. Previous work by these authors showed that the separate seasonal trends of agricultural and non-agricultural fire could be extracted from large-scale fire observation and land use datasets. This study builds on that research, describing the derivation and application of a statistical method to estimate both the seasonality and amount of cropland, pasture, and other fire based on observations from satellite-based remote sensing products. We demonstrate that our approach is flexible enough to allow the incorporation of alternative high-quality observations of fire and/or land use that might be available only for certain regions. Results for a number of large regions around the world show that these two kinds of agricultural fire often differ in their extent and seasonality from each other and from burning on other land in ways that reflect known management practices. For example, we find that pasture in north-central sub-Saharan Africa tends to burn earlier than non-agricultural land; this can be attributed to pastoralists preventively burning their land early in the dry season so as to avoid severe, uncontrolled burns under more dangerous fire conditions later. Both the timing and extent of agricultural fires prove to be regionally specific; our method allows these geographically distinct patterns to be fully appreciated. The local and global differences in seasonality and amount of fire between different land-use types suggest that dynamic global vegetation models

  8. Automatic detection of motion blur in intravital video microscopy image sequences via directional statistics of log-Gabor energy maps.

    PubMed

    Ferrari, Ricardo J; Pinto, Carlos H Villa; da Silva, Bruno C Gregório; Bernardes, Danielle; Carvalho-Tavares, Juliana

    2015-02-01

    Intravital microscopy is an important experimental tool for the study of cellular and molecular mechanisms of the leukocyte-endothelial interactions in the microcirculation of various tissues and in different inflammatory conditions of in vivo specimens. However, due to the limited control over the conditions of the image acquisition, motion blur and artifacts, resulting mainly from the heartbeat and respiratory movements of the in vivo specimen, will very often be present. This problem can significantly undermine the results of either visual or computerized analysis of the acquired video images. Since only a fraction of the total number of images are usually corrupted by severe motion blur, it is necessary to have a procedure to automatically identify such images in the video for either further restoration or removal. This paper proposes a new technique for the detection of motion blur in intravital video microscopy based on directional statistics of local energy maps computed using a bank of 2D log-Gabor filters. Quantitative assessment using both artificially corrupted images and real microscopy data were conducted to test the effectiveness of the proposed method. Results showed an area under the receiver operating characteristic curve (AUC) of 0.95 (AUC = 0.95; 95 % CI 0.93-0.97) when tested on 329 video images visually ranked by four observers.

  9. Statistical parametric mapping demonstrates asymmetric uptake with Tc-99m ECD and Tc-99m HMPAO SPECT in normal brain.

    PubMed

    Brinkmann, Benjamin H; Jones, David T; Stead, Matt; Kazemi, Noojan; O'Brien, Terence J; So, Elson L; Blumenfeld, Hal; Mullan, Brian P; Worrell, Gregory A

    2012-01-01

    Tc-99m ethyl cysteinate diethylester (ECD) and Tc-99m hexamethyl propylene amine oxime (HMPAO) are commonly used for single-photon emission computed tomography (SPECT) studies of a variety of neurologic disorders. Although these tracers have been very helpful in diagnosing and guiding treatment of neurologic disease, data describing the distribution and laterality of these tracers in normal resting brain are limited. Advances in quantitative functional imaging have demonstrated the value of using resting studies from control populations as a baseline to account for physiologic fluctuations in cerebral perfusion. Here, we report results from 30 resting Tc-99m ECD SPECT scans and 14 resting Tc-99m HMPAO scans of normal volunteers with no history of neurologic disease. Scans were analyzed with regions of interest and with statistical parametric mapping, with comparisons performed laterally (left vs. right), as well as for age, gender, and handedness. The results show regions of significant asymmetry in the normal controls affecting widespread areas in the cerebral hemispheres, but most marked in superior parietotemporal region and frontal lobes. The results have important implications for the use of normal control SPECT images in the evaluation of patients with neurologic disease.

  10. A 12-step user guide for analyzing voxel-wise gray matter asymmetries in statistical parametric mapping (SPM).

    PubMed

    Kurth, Florian; Gaser, Christian; Luders, Eileen

    2015-02-01

    Voxel-based morphometry (VBM) has been proven capable of capturing cerebral gray matter asymmetries with a high (voxel-wise) regional specificity. However, a standardized reference on how to conduct voxel-wise asymmetry analyses is missing. This protocol provides the scientific community with a carefully developed guide describing, in 12 distinct steps, how to take structural images from data pre-processing, via statistical analysis, to the final interpretation of the significance maps. Key adaptations compared with the standard VBM workflow involve establishing a voxel-wise hemispheric correspondence, capturing the direction and degree of asymmetry and preventing a blurring of information across hemispheres. The workflow incorporates the most recent methodological developments, including high-dimensional spatial normalization and partial volume estimations. Although the protocol is primarily designed to enable relatively inexperienced users to conduct a voxel-based asymmetry analysis on their own, it may also be useful to experienced users who wish to efficiently adapt their existing scripts or pipelines.

  11. PRIMAL: Page Rank-Based Indoor Mapping and Localization Using Gene-Sequenced Unlabeled WLAN Received Signal Strength.

    PubMed

    Zhou, Mu; Zhang, Qiao; Xu, Kunjie; Tian, Zengshan; Wang, Yanmeng; He, Wei

    2015-01-01

    Due to the wide deployment of wireless local area networks (WLAN), received signal strength (RSS)-based indoor WLAN localization has attracted considerable attention in both academia and industry. In this paper, we propose a novel page rank-based indoor mapping and localization (PRIMAL) by using the gene-sequenced unlabeled WLAN RSS for simultaneous localization and mapping (SLAM). Specifically, first of all, based on the observation of the motion patterns of the people in the target environment, we use the Allen logic to construct the mobility graph to characterize the connectivity among different areas of interest. Second, the concept of gene sequencing is utilized to assemble the sporadically-collected RSS sequences into a signal graph based on the transition relations among different RSS sequences. Third, we apply the graph drawing approach to exhibit both the mobility graph and signal graph in a more readable manner. Finally, the page rank (PR) algorithm is proposed to construct the mapping from the signal graph into the mobility graph. The experimental results show that the proposed approach achieves satisfactory localization accuracy and meanwhile avoids the intensive time and labor cost involved in the conventional location fingerprinting-based indoor WLAN localization. PMID:26404274

  12. PRIMAL: Page Rank-Based Indoor Mapping and Localization Using Gene-Sequenced Unlabeled WLAN Received Signal Strength

    PubMed Central

    Zhou, Mu; Zhang, Qiao; Xu, Kunjie; Tian, Zengshan; Wang, Yanmeng; He, Wei

    2015-01-01

    Due to the wide deployment of wireless local area networks (WLAN), received signal strength (RSS)-based indoor WLAN localization has attracted considerable attention in both academia and industry. In this paper, we propose a novel page rank-based indoor mapping and localization (PRIMAL) by using the gene-sequenced unlabeled WLAN RSS for simultaneous localization and mapping (SLAM). Specifically, first of all, based on the observation of the motion patterns of the people in the target environment, we use the Allen logic to construct the mobility graph to characterize the connectivity among different areas of interest. Second, the concept of gene sequencing is utilized to assemble the sporadically-collected RSS sequences into a signal graph based on the transition relations among different RSS sequences. Third, we apply the graph drawing approach to exhibit both the mobility graph and signal graph in a more readable manner. Finally, the page rank (PR) algorithm is proposed to construct the mapping from the signal graph into the mobility graph. The experimental results show that the proposed approach achieves satisfactory localization accuracy and meanwhile avoids the intensive time and labor cost involved in the conventional location fingerprinting-based indoor WLAN localization. PMID:26404274

  13. PRIMAL: Page Rank-Based Indoor Mapping and Localization Using Gene-Sequenced Unlabeled WLAN Received Signal Strength.

    PubMed

    Zhou, Mu; Zhang, Qiao; Xu, Kunjie; Tian, Zengshan; Wang, Yanmeng; He, Wei

    2015-09-25

    Due to the wide deployment of wireless local area networks (WLAN), received signal strength (RSS)-based indoor WLAN localization has attracted considerable attention in both academia and industry. In this paper, we propose a novel page rank-based indoor mapping and localization (PRIMAL) by using the gene-sequenced unlabeled WLAN RSS for simultaneous localization and mapping (SLAM). Specifically, first of all, based on the observation of the motion patterns of the people in the target environment, we use the Allen logic to construct the mobility graph to characterize the connectivity among different areas of interest. Second, the concept of gene sequencing is utilized to assemble the sporadically-collected RSS sequences into a signal graph based on the transition relations among different RSS sequences. Third, we apply the graph drawing approach to exhibit both the mobility graph and signal graph in a more readable manner. Finally, the page rank (PR) algorithm is proposed to construct the mapping from the signal graph into the mobility graph. The experimental results show that the proposed approach achieves satisfactory localization accuracy and meanwhile avoids the intensive time and labor cost involved in the conventional location fingerprinting-based indoor WLAN localization.

  14. The putative lipid transporter, Arv1, is required for activating pheromone-induced MAP kinase signaling in Saccharomyces cerevisiae.

    PubMed

    Villasmil, Michelle L; Ansbach, Alison; Nickels, Joseph T

    2011-02-01

    Saccharomyces cerevisiae haploid cells respond to extrinsic mating signals by forming polarized projections (shmoos), which are necessary for conjugation. We have examined the role of the putative lipid transporter, Arv1, in yeast mating, particularly the conserved Arv1 homology domain (AHD) within Arv1 and its role in this process. Previously it was shown that arv1 cells harbor defects in sphingolipid and glycosylphosphatidylinositol (GPI) biosyntheses and may harbor sterol trafficking defects. Here we demonstrate that arv1 cells are mating defective and cannot form shmoos. They lack the ability to initiate pheromone-induced G1 cell cycle arrest, due to failure to polarize PI(4,5)P(2) and the Ste5 scaffold, which results in weakened MAP kinase signaling activity. A mutant Ste5, Ste5(Q59L), which binds more tightly to the plasma membrane, suppresses the MAP kinase signaling defects of arv1 cells. Filipin staining shows arv1 cells contain altered levels of various sterol microdomains that persist throughout the mating process. Data suggest that the sterol trafficking defects of arv1 affect PI(4,5)P(2) polarization, which causes a mislocalization of Ste5, resulting in defective MAP kinase signaling and the inability to mate. Importantly, our studies show that the AHD of Arv1 is required for mating, pheromone-induced G1 cell cycle arrest, and for sterol trafficking.

  15. The Putative Lipid Transporter, Arv1, Is Required for Activating Pheromone-Induced MAP Kinase Signaling in Saccharomyces cerevisiae

    PubMed Central

    Villasmil, Michelle L.; Ansbach, Alison; Nickels, Joseph T.

    2011-01-01

    Saccharomyces cerevisiae haploid cells respond to extrinsic mating signals by forming polarized projections (shmoos), which are necessary for conjugation. We have examined the role of the putative lipid transporter, Arv1, in yeast mating, particularly the conserved Arv1 homology domain (AHD) within Arv1 and its role in this process. Previously it was shown that arv1 cells harbor defects in sphingolipid and glycosylphosphatidylinositol (GPI) biosyntheses and may harbor sterol trafficking defects. Here we demonstrate that arv1 cells are mating defective and cannot form shmoos. They lack the ability to initiate pheromone-induced G1 cell cycle arrest, due to failure to polarize PI(4,5)P2 and the Ste5 scaffold, which results in weakened MAP kinase signaling activity. A mutant Ste5, Ste5Q59L, which binds more tightly to the plasma membrane, suppresses the MAP kinase signaling defects of arv1 cells. Filipin staining shows arv1 cells contain altered levels of various sterol microdomains that persist throughout the mating process. Data suggest that the sterol trafficking defects of arv1 affect PI(4,5)P2 polarization, which causes a mislocalization of Ste5, resulting in defective MAP kinase signaling and the inability to mate. Importantly, our studies show that the AHD of Arv1 is required for mating, pheromone-induced G1 cell cycle arrest, and for sterol trafficking. PMID:21098723

  16. Characterization of infrared imaging performance within a general statistical framework for environmental impacts on battlefield signals and sensing

    NASA Astrophysics Data System (ADS)

    Wilson, D. Keith; Borden, Christopher T.; Bettencourt, Elizabeth S.; Yamamoto, Kenneth K.

    2013-05-01

    The Environmental Awareness for Sensor and Emitter Employment (EASEE) software models the impacts of terrain and weather on a diverse range of battlefield sensing systems. The goal is to provide mission planning tools that realistically capture complex environmental factors impacting sensor performance, yet are simple enough for users with little specialized training. This paper describes incorporation of infrared (IR) modeling into EASEE, and the subsequent challenges of supporting imaging sensors within a framework that had previously evolved primarily for non-imaging sensors, such as acoustic and seismic. The design requires independently interchangeable modules for signature generation, propagation, and signal processing. Sensor performance metrics, such as probability of detection, are characterized statistically rather than through simulation of actual images. Some key enhancements needed to support imaging sensors were: (1) geometric models for targets, (2) packaging of multiple attributes representing target image properties (radiance, projected area, and spatial spectrum), (3) explicitly distinguishing between signals for the background, target of interest, and nuisance targets, and (4) calculation of apparent temperature differences (as opposed to incoherent energy summation). Target signatures are generated using MuSES (Multi-Service Electro-optic Signature), whereas the IR background properties are generated using FASST (Fast All-Season Soil STrength) and numerical weather prediction models. Propagation is handled primarily with MODTRAN (MODerate resolution atmospheric TRANsmission), although simpler models such as a line-of-sight calculation can also be employed. The Johnson criteria were added to the available library of detection algorithms.

  17. Map of Pseudo-F-statistics of seismic noise parameters as an indicator of current seismic danger in Japan

    NASA Astrophysics Data System (ADS)

    Lyubushin, Alexey

    2016-04-01

    The problem of estimate of current seismic danger based on monitoring of seismic noise properties from broadband seismic network F-net in Japan (84 stations) is considered. Variations of the following seismic noise parameters are analyzed: multifractal singularity spectrum support width, generalized Hurst exponent, minimum Hölder-Lipschitz exponent and minimum normalized entropy of squared orthogonal wavelet coefficients. These parameters are estimated within adjacent time windows of the length 1 day for seismic noise waveforms from each station. Calculating daily median values of these parameters by all stations provides 4-dimensional time series which describes integral properties of the seismic noise in the region covered by the network. Cluster analysis is applied to the sequence of clouds of 4-dimensional vectors within moving time window of the length 365 days with mutual shift 3 days starting from the beginning of 1997 up to the current time. The purpose of the cluster analysis is to find the best number of clusters (BNC) from probe numbers which are varying from 1 up to the maximum value 40. The BNC is found from the maximum of pseudo-F-statistics (PFS). A 2D map could be created which presents dependence of PFS on the tested probe number of clusters and the right-hand end of moving time window which is rather similar to usual spectral time-frequency diagrams. In the paper [1] it was shown that the BNC before Tohoku mega-earthquake on March 11, 2011, has strongly chaotic regime with jumps from minimum up to maximum values in the time interval 1 year before the event and this time intervals was characterized by high PFS values. The PFS-map is proposed as the method for extracting time intervals with high current seismic danger. The next danger time interval after Tohoku mega-EQ began at the end of 2012 and was finished at the middle of 2013. Starting from middle of 2015 the high PFS values and chaotic regime of BNC variations were returned. This could be

  18. High-Resolution fMRI Maps of Cortical Activation in Nonhuman Primates: Correlation with Intrinsic Signal Optical Images

    PubMed Central

    Roe, Anna W.; Chen, Li Min

    2009-01-01

    One of the most widely used functional brain mapping tools is blood oxygen level–dependent (BOLD) functional magnetic resonance imaging (fMRI). This method has contributed to new understandings of the functional roles of different areas in the human brain. However, its ability to map cerebral cortex at high spatial (submillimeter) resolution is still unknown. Other methods such as single- and multiunit electrophysiology and intrinsic signal optical imaging have revealed submillimeter resolution of sensory topography and cortical columnar activations. However, they are limited either by spatial scale (electrophysiology characterizes only local groups of neurons) or by the inability to monitor deep structures in the brain (i.e., cortical regions buried in sulci or subcortical structures). A method that could monitor all regions of the brain at high spatial resolution would be ideal. This capacity would open the doors to investigating, for example, how networks of cerebral cortical columns relate to or produce behavior. In this article we demonstrate that, without benefit of contrast agents, at a magnetic field strength of 9.4 tesla, BOLD fMRI can reveal millimeter-sized topographic maps of digit representation in the somatosensory cortex of the anesthetized squirrel monkey. Furthermore, by mapping the “funneling illusion,” it is possible to detect even submillimeter shifts in activation in the cortex. Our data suggest that at high magnetic field strength, the positive BOLD signal can be used to reveal high spatial resolution maps of brain activity, a finding that weakens previous notions about the ultimate spatial specificity of the positive BOLD signal. PMID:18172338

  19. [Methods for the detection of ventricular late potentials. High amplification ECG, signal averaging technic, frequency analysis and intracardiac mapping].

    PubMed

    Hombach, V; Eggeling, T; Höher, M; Höpp, H W; Kochs, M; Giel, I; Emsermann, P; Hirche, H; Hilger, H H

    1988-06-01

    Circumscribed areas of injured myocardium which lead to late ventricular depolarization represent the pathologic-anatomic substrate for reentry mechanisms potentially capable of propagating ventricular tachycardia at the ventricular level. If the myocardial area from which delayed ventricular depolarization and, consequently, late potentials eminate, exceeds a critical minimal size, documentation of such signals can not only be achieved with direct endocardial mapping or catheter mapping but also by means of special high-resolution ECG techniques from the body surface. Since high amplification of the conventional ECG results in registration of noise signals in amplitude of up to 50 microV, late potentials with their amplitudes at the body surface ranging from 5 to a maximum of 20 microV, can only be discriminated after substantial enhancement of the signal-to-noise ratio. The noise arises from no less than three sources: physiologic noise, for example, from muscle activity; electronic noise from amplifiers and background noise of 50 or 60 Hz, respectively. To improve the signal-to-noise ratio, currently three methods are employed: sequential or temporal signal averaging, spatial signal averaging and fast Fourier transformation analysis of the frequency spectrum of the highly-amplified ECG. Temporal signal averaging has the purpose of smoothing randomly-occurring background noise and, at a specified point in time of the ECG cycle, to sum the signal incurred. The effectivity of this technique, however, is subject to certain conditions: the signal to be registered and the background noise must be independent from each other, the noise must be stationary and show normal random distribution, the signal of interest must be periodic and/or coupled with a fixed interval to a point in the ECG cycle which can be used as a trigger. The quality of the averaged signal is dependent on trigger stability. There are three approaches to trigger processing: voltage threshold

  20. Performance mapping of the STM4-120 kinematic Stirling engine using a statistical design of experiments method

    SciTech Connect

    Powell, M.A.; Rawlinson, K.S.

    1992-01-01

    A kinetic Stirling cycle engine, the Stirling Thermal Motors (STM) STM4-120, was tested at the Sandia National Laboratories Engine Test Facility (ETF) from March 1989--August 1992. Sandia is interested in determining this engine's potential for solar-thermal-electric applications. The last round of testing was conducted from July--August 1992 using Sandia-designed gas-fired heat pipe evaporators as the heat input system to the engine. The STM4-120 was performance mapped over a range of sodium vapor temperatures, cooling water temperatures, and cycle pressures. The resulting shaft power output levels ranged from 5--9 kW. The engine demonstrated high conversion efficiency (24--31%) even though the power output level was less than 40% of the rated output of 25 kW. The engine had been previously derated from 25 kW to 10 kW shaft power due to mechanical limitations that were identified by STM during parallel testing at their facility in Ann Arbor, MI. A statistical method was used to design the experiment, to choose the experimental points, and to generate correlation equations describing the engine performance given the operating parameters. The testing was trunacted due to a failure of the heat pipe system caused by entrainment of liquid sodium in the condenser section of the heat pipes. Enough data was gathered to generate the correlations and to demonstrate the experimental technique. The correlation is accurate in the experimental space and is simple enough for use in hand calculations and spreadsheet-based system models. Use of this method can simplify the construction of accurate performance and economic models of systems in which the engine is a component. The purpose of this paper is to present the method used to design the experiments and to analyze the performance data.

  1. Hepatitis B virus HBx protein activates Ras-GTP complex formation and establishes a Ras, Raf, MAP kinase signaling cascade.

    PubMed Central

    Benn, J; Schneider, R J

    1994-01-01

    Hepatitis B virus produces a small (154-amino acid) transcriptional transactivating protein, HBx, which is required for viral infection and has been implicated in virus-mediated liver oncogenesis. However, the molecular mechanism for HBx activity and its possible influence on cell proliferation have remained obscure. A number of studies suggest that HBx may stimulate transcription by indirectly activating transcription factors, possibly by influencing cell signaling pathways. We now present biochemical evidence that HBx activates Ras and rapidly induces a cytoplasmic signaling cascade linking Ras, Raf, and mitogen-activated protein kinase (MAP kinase), leading to transcriptional transactivation. HBx strongly elevates levels of GTP-bound Ras, activated and phosphorylated Raf, and tyrosine-phosphorylated and activated MAP kinase. Transactivation of transcription factor AP-1 by HBx is blocked by inhibition of Ras or Raf activities but not by inhibition of Ca(2+)- and diacylglycerol-dependent protein kinase C. HBx was also found to stimulate DNA synthesis in serum-starved cells. The hepatitis B virus HBx protein therefore stimulates Ras-GTP complex formation and promotes downstream signaling through Raf and MAP kinases, and may influence cell proliferation. Images PMID:7937954

  2. The Arabidopsis MAP kinase kinase 7: A crosstalk point between Auxin signaling and defense responses?

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Plant-pathogen interaction induces a complex host response that coordinates various signaling pathways through multiple signal molecules. Besides the well-documented signal molecules salicylic acid (SA), ethylene and jasmonic acid, auxin is emerging as an important player in this response. We recent...

  3. Endocannabinoid signaling is required for development and critical period plasticity of the whisker map in somatosensory cortex

    PubMed Central

    Li, Lu; Bender, Kevin J.; Drew, Patrick J.; Jadhav, Shantanu P.; Sylwestrak, Emily; Feldman, Daniel E.

    2009-01-01

    Summary Type 1 cannabinoid (CB1) receptors mediate widespread synaptic plasticity, but how this contributes to systems-level plasticity and development in vivo is unclear. We tested whether CB1 signaling is required for development and plasticity of the whisker map in rat somatosensory cortex. Treatment with the CB1 antagonist AM251 during an early critical period for layer (L) 2/3 development (beginning postnatal day [P] 12–16) disrupted whisker map development, leading to inappropriate whisker tuning in L2/3 column edges and a blurred map. Early AM251 treatment also prevented experience-dependent plasticity in L2/3, including deprivation-induced synapse weakening and weakening of deprived whisker responses. CB1 blockade after P25 did not disrupt map development or plasticity. AM251 had no acute effect on sensory-evoked spiking, and only modestly affected field potentials, suggesting that plasticity effects were not secondary to gross activity changes. These findings implicate CB1-dependent plasticity in systems-level development and early postnatal plasticity of the whisker map. PMID:19945395

  4. Temporal Comparison Between NIRS and EEG Signals During a Mental Arithmetic Task Evaluated with Self-Organizing Maps.

    PubMed

    Oyama, Katsunori; Sakatani, Kaoru

    2016-01-01

    Simultaneous monitoring of brain activity with near-infrared spectroscopy and electroencephalography allows spatiotemporal reconstruction of the hemodynamic response regarding the concentration changes in oxyhemoglobin and deoxyhemoglobin that are associated with recorded brain activity such as cognitive functions. However, the accuracy of state estimation during mental arithmetic tasks is often different depending on the length of the segment for sampling of NIRS and EEG signals. This study compared the results of a self-organizing map and ANOVA, which were both used to assess the accuracy of state estimation. We conducted an experiment with a mental arithmetic task performed by 10 participants. The lengths of the segment in each time frame for observation of NIRS and EEG signals were compared with the 30-s, 1-min, and 2-min segment lengths. The optimal segment lengths were different for NIRS and EEG signals in the case of classification of feature vectors into the states of performing a mental arithmetic task and being at rest.

  5. On the optimality of the MAP estimation loop for carrier phase tracking BPSK and QPSK signals

    NASA Technical Reports Server (NTRS)

    Simon, M. K.

    1979-01-01

    Starting with MAP estimation theory as a basis for optimally estimating carrier phase of BPSK and QPSK modulations, it is shown in this paper that the closed loop phase trackers, which are motivated by this approach, are indeed closed loop optimum in the minimum mean-square phase tracking jitter sense. The corresponding squaring loss performance of these so-called MAP estimation loops is compared with that of more practical implementations wherein the hyperbolic tangent nonlinearity is approximated by simpler functions.

  6. Mapping Neuronal Activation and the Influence of Adrenergic Signaling during Contextual Memory Retrieval

    ERIC Educational Resources Information Center

    Zhang, Wei-Ping; Guzowski, John F.; Thomas, Steven A.

    2005-01-01

    We recently described a critical role for adrenergic signaling in the hippocampus during contextual and spatial memory retrieval. To determine which neurons are activated by contextual memory retrieval and its sequelae in the presence and absence of adrenergic signaling, transcriptional imaging for the immediate-early gene "Arc" was used in…

  7. TRAF2 multitasking in TNF receptor-induced signaling to NF-κB, MAP kinases and cell death.

    PubMed

    Borghi, Alice; Verstrepen, Lynn; Beyaert, Rudi

    2016-09-15

    Tumor Necrosis Factor (TNF) is a potent inflammatory cytokine that exerts its functions through the activation of two distinct receptors, TNFR1 and TNFR2. Both receptors can activate canonical NF-κB and JNK MAP kinase signaling, while TNFR2 can also activate non-canonical NF-κB signaling, leading to numerous changes in gene expression that drive inflammation, cell proliferation and cell survival. On the other hand, TNFR1 also activates signaling pathways leading to cell death by either apoptosis or necroptosis, depending on the cellular context. A key player in TNFR1- and TNFR2-induced signaling is the RING finger protein TRAF2, which is recruited to both receptors upon their stimulation. TRAF2 exerts multiple receptor-specific functions but also mediates cross-talk between TNFR1 and TNFR2, dictating the outcome of TNF stimulation. In this review, we provide an overview of the positive and negative regulatory role of TRAF2 in different TNFR1 and TNFR2 signaling pathways. We discuss the underlying molecular mechanism of action, distinguishing between TRAF2 scaffold and E3 ubiquitin ligase functions, and the regulation of TRAF2 by specific post-translational modifications. Finally, we elaborate on some possible strategies to modulate TRAF2 function in the context of therapeutic targeting in autoimmunity and cancer.

  8. TRAF2 multitasking in TNF receptor-induced signaling to NF-κB, MAP kinases and cell death.

    PubMed

    Borghi, Alice; Verstrepen, Lynn; Beyaert, Rudi

    2016-09-15

    Tumor Necrosis Factor (TNF) is a potent inflammatory cytokine that exerts its functions through the activation of two distinct receptors, TNFR1 and TNFR2. Both receptors can activate canonical NF-κB and JNK MAP kinase signaling, while TNFR2 can also activate non-canonical NF-κB signaling, leading to numerous changes in gene expression that drive inflammation, cell proliferation and cell survival. On the other hand, TNFR1 also activates signaling pathways leading to cell death by either apoptosis or necroptosis, depending on the cellular context. A key player in TNFR1- and TNFR2-induced signaling is the RING finger protein TRAF2, which is recruited to both receptors upon their stimulation. TRAF2 exerts multiple receptor-specific functions but also mediates cross-talk between TNFR1 and TNFR2, dictating the outcome of TNF stimulation. In this review, we provide an overview of the positive and negative regulatory role of TRAF2 in different TNFR1 and TNFR2 signaling pathways. We discuss the underlying molecular mechanism of action, distinguishing between TRAF2 scaffold and E3 ubiquitin ligase functions, and the regulation of TRAF2 by specific post-translational modifications. Finally, we elaborate on some possible strategies to modulate TRAF2 function in the context of therapeutic targeting in autoimmunity and cancer. PMID:26993379

  9. Mapping Type IV Secretion Signals on the Primase Encoded by the Broad-Host-Range Plasmid R1162 (RSF1010)

    PubMed Central

    2015-01-01

    ABSTRACT The plasmid R1162 (RSF1010) encodes a primase essential for its replication. This primase makes up the C-terminal part of MobA, a multifunctional protein with the relaxase as a separate N-terminal domain. The primase is also translated separately as the protein RepB′. Here, we map two signals for type IV secretion onto the recently solved structure of RepB′. One signal is located internally within RepB′ and consists of a long α-helix and an adjacent disordered region rich in arginines. The second signal is made up of the same α-helix and a second, arginine-rich region at the C-terminal end of the protein. Successive arginine-to-alanine substitutions revealed that either signal can be utilized by the type IV secretion complex of the plasmid R751. The internal signal also enables conjugal transfer when linked to the relaxase part of MobA. Both signals are similar to those previously identified for type IV secretion substrates in the Vir system of Agrobacterium tumefaciens. Moreover, the C-terminal arginine-rich segment of RepB′ has been shown to be secreted by Vir. However, with R751, the signals require MobB, an R1162-encoded accessory protein active in conjugal transfer. The results of two-hybrid assays revealed that MobB interacts, via its membrane-associated domain, with the R751 plasmid coupling protein TraG. In addition, MobB interacts with a region of MobA just outside the RepB′ domain. Therefore, MobB is likely an adaptor that is essential for recognition of the primase-associated signals by the R751 secretion machinery. IMPORTANCE For most plasmids, type IV secretion is an intrinsic part of the mechanism for conjugal transfer. Protein relaxases, bound to the 5′ end of the transferring strand, are mobilized into recipient cells by the type IV pathway. In this work, we identify and characterize two signals for secretion in the primase domain of MobA, the relaxase of the IncQ plasmid R1162 (RSF1010). We also show that the adaptor protein

  10. Hail statistic in Western Europe based on a hyrid cell-tracking algorithm combining radar signals with hailstone observations

    NASA Astrophysics Data System (ADS)

    Fluck, Elody

    2015-04-01

    Hail statistic in Western Europe based on a hybrid cell-tracking algorithm combining radar signals with hailstone observations Elody Fluck¹, Michael Kunz¹ , Peter Geissbühler², Stefan P. Ritz² With hail damage estimated over Billions of Euros for a single event (e.g., hailstorm Andreas on 27/28 July 2013), hail constitute one of the major atmospheric risks in various parts of Europe. The project HAMLET (Hail Model for Europe) in cooperation with the insurance company Tokio Millennium Re aims at estimating hail probability, hail hazard and, combined with vulnerability, hail risk for several European countries (Germany, Switzerland, France, Netherlands, Austria, Belgium and Luxembourg). Hail signals are obtained from radar reflectivity since this proxy is available with a high temporal and spatial resolution using several hail proxies, especially radar data. The focus in the first step is on Germany and France for the periods 2005- 2013 and 1999 - 2013, respectively. In the next step, the methods will be transferred and extended to other regions. A cell-tracking algorithm TRACE2D was adjusted and applied to two dimensional radar reflectivity data from different radars operated by European weather services such as German weather service (DWD) and French weather service (Météo-France). Strong convective cells are detected by considering 3 connected pixels over 45 dBZ (Reflectivity Cores RCs) in a radar scan. Afterwards, the algorithm tries to find the same RCs in the next 5 minute radar scan and, thus, track the RCs centers over time and space. Additional information about hailstone diameters provided by ESWD (European Severe Weather Database) is used to determine hail intensity of the detected hail swaths. Maximum hailstone diameters are interpolated along and close to the individual hail tracks giving an estimation of mean diameters for the detected hail swaths. Furthermore, a stochastic event set is created by randomizing the parameters obtained from the

  11. Non extensive statistical physics applied in fracture-induced electric signals during triaxial deformation of Carrara marble

    NASA Astrophysics Data System (ADS)

    Cartwright-Taylor, Alexis; Vallianatos, Filippos; Sammonds, Peter

    2014-05-01

    We have conducted room-temperature, triaxial compression experiments on samples of Carrara marble, recording concurrently acoustic and electric current signals emitted during the deformation process as well as mechanical loading information and ultrasonic wave velocities. Our results reveal that in a dry non-piezoelectric rock under simulated crustal pressure conditions, a measurable electric current (nA) is generated within the stressed sample. The current is detected only in the region beyond (quasi-)linear elastic deformation; i.e. in the region of permanent deformation beyond the yield point of the material and in the presence of microcracking. Our results extend to shallow crustal conditions previous observations of electric current signals in quartz-free rocks undergoing uniaxial deformation and support the idea of a universal electrification mechanism related to deformation. Confining pressure conditions of our slow strain rate (10-6 s-1) experiments range from the purely brittle regime (10 MPa) to the semi-brittle transition (30-100MPa) where cataclastic flow is the dominant deformation mechanism. Electric current is generated under all confining pressures,implying the existence of a current-producing mechanism during both microfracture and frictional sliding. Some differences are seen in the current evolution between these two regimes, possibly related to crack localisation. In all cases, the measured electric current exhibits episodes of strong fluctuations over short timescales; calm periods punctuated by bursts of strong activity. For the analysis, we adopt an entropy-based statistical physics approach (Tsallis, 1988), particularly suited to the study of fracture related phenomena. We find that the probability distribution of normalised electric current fluctuations over short time intervals (0.5 s) can be well described by a q-Gaussian distribution of a form similar to that which describes turbulent flows. This approach yields different entropic

  12. Detection of prostate cancer by integration of line-scan diffusion, T2-mapping and T2-weighted magnetic resonance imaging; a multichannel statistical classifier.

    PubMed

    Chan, Ian; Wells, William; Mulkern, Robert V; Haker, Steven; Zhang, Jianqing; Zou, Kelly H; Maier, Stephan E; Tempany, Clare M C

    2003-09-01

    A multichannel statistical classifier for detecting prostate cancer was developed and validated by combining information from three different magnetic resonance (MR) methodologies: T2-weighted, T2-mapping, and line scan diffusion imaging (LSDI). From these MR sequences, four different sets of image intensities were obtained: T2-weighted (T2W) from T2-weighted imaging, Apparent Diffusion Coefficient (ADC) from LSDI, and proton density (PD) and T2 (T2 Map) from T2-mapping imaging. Manually segmented tumor labels from a radiologist, which were validated by biopsy results, served as tumor "ground truth." Textural features were extracted from the images using co-occurrence matrix (CM) and discrete cosine transform (DCT). Anatomical location of voxels was described by a cylindrical coordinate system. A statistical jack-knife approach was used to evaluate our classifiers. Single-channel maximum likelihood (ML) classifiers were based on 1 of the 4 basic image intensities. Our multichannel classifiers: support vector machine (SVM) and Fisher linear discriminant (FLD), utilized five different sets of derived features. Each classifier generated a summary statistical map that indicated tumor likelihood in the peripheral zone (PZ) of the prostate gland. To assess classifier accuracy, the average areas under the receiver operator characteristic (ROC) curves over all subjects were compared. Our best FLD classifier achieved an average ROC area of 0.839(+/-0.064), and our best SVM classifier achieved an average ROC area of 0.761(+/-0.043). The T2W ML classifier, our best single-channel classifier, only achieved an average ROC area of 0.599(+/-0.146). Compared to the best single-channel ML classifier, our best multichannel FLD and SVM classifiers have statistically superior ROC performance (P=0.0003 and 0.0017, respectively) from pairwise two-sided t-test. By integrating the information from multiple images and capturing the textural and anatomical features in tumor areas, summary

  13. Human cervical cancer cells use Ca2+ signalling, protein tyrosine phosphorylation and MAP kinase in regulatory volume decrease.

    PubMed

    Shen, M R; Chou, C Y; Browning, J A; Wilkins, R J; Ellory, J C

    2001-12-01

    1. This study was aimed at identifying the signalling pathways involved in the activation of volume-regulatory mechanisms of human cervical cancer cells. 2. Osmotic swelling of human cervical cancer cells induced a substantial increase in intracellular Ca2+ ([Ca2+]i) by the activation of Ca2+ entry across the cell membrane, as well as Ca2+ release from intracellular stores. This Ca2+ signalling was critical for the normal regulatory volume decrease (RVD) response. 3. The activation of swelling-activated ion and taurine transport was significantly inhibited by tyrosine kinase inhibitors (genistein and tyrphostin AG 1478) and potentiated by the tyrosine phosphatase inhibitor Na3VO4. However, the Src family of tyrosine kinases was not involved in regulation of the swelling-activated Cl- channel. 4. Cell swelling triggered mitogen-activated protein (MAP) kinase cascades leading to the activation of extracellular signal-regulated kinase 1 and 2 (ERK1/ERK2) and p38 kinase. The volume-responsive ERK1/ERK2 signalling pathway linked with the activation of K+ and Cl- channels, and taurine transport. However, the volume-regulatory mechanism was independent of the activation of p38 MAP kinase. 5. The phosphorylated ERK1/ERK2 expression following a hypotonic shock was up-regulated by protein kinase C (PKC) activator phorbol 12-myristate 13-acetate (PMA) and down-regulated by PKC inhibitor staurosporine. The response of ERK activation to hypotonicity also required Ca2+ entry and depended on tyrosine kinase and mitogen-activated/ERK-activating kinase (MEK) activity. 6. Considering the results overall, osmotic swelling promotes the activation of tyrosine kinase and ERK1/ERK2 and raises intracellular Ca2+, all of which play a crucial role in the volume-regulatory mechanism of human cervical cancer cells. PMID:11731569

  14. Mechanisms of cell signaling by nitric oxide and peroxynitrite: from mitochondria to MAP kinases

    NASA Technical Reports Server (NTRS)

    Levonen, A. L.; Patel, R. P.; Brookes, P.; Go, Y. M.; Jo, H.; Parthasarathy, S.; Anderson, P. G.; Darley-Usmar, V. M.

    2001-01-01

    Many of the biological and pathological effects of nitric oxide (NO) are mediated through cell signaling pathways that are initiated by NO reacting with metalloproteins. More recently, it has been recognized that the reaction of NO with free radicals such as superoxide and the lipid peroxyl radical also has the potential to modulate redox signaling. Although it is clear that NO can exert both cytotoxic and cytoprotective actions, the focus of this overview are those reactions that could lead to protection of the cell against oxidative stress in the vasculature. This will include the induction of antioxidant defenses such as glutathione, activation of mitogen-activated protein kinases in response to blood flow, and modulation of mitochondrial function and its impact on apoptosis. Models are presented that show the increased synthesis of glutathione in response to shear stress and inhibition of cytochrome c release from mitochondria. It appears that in the vasculature NO-dependent signaling pathways are of three types: (i) those involving NO itself, leading to modulation of mitochondrial respiration and soluble guanylate cyclase; (ii) those that involve S-nitrosation, including inhibition of caspases; and (iii) autocrine signaling that involves the intracellular formation of peroxynitrite and the activation of the mitogen-activated protein kinases. Taken together, NO plays a major role in the modulation of redox cell signaling through a number of distinct pathways in a cellular setting.

  15. Arkansas StreamStats: a U.S. Geological Survey web map application for basin characteristics and streamflow statistics

    USGS Publications Warehouse

    Pugh, Aaron L.

    2014-01-01

    Users of streamflow information often require streamflow statistics and basin characteristics at various locations along a stream. The USGS periodically calculates and publishes streamflow statistics and basin characteristics for streamflowgaging stations and partial-record stations, but these data commonly are scattered among many reports that may or may not be readily available to the public. The USGS also provides and periodically updates regional analyses of streamflow statistics that include regression equations and other prediction methods for estimating statistics for ungaged and unregulated streams across the State. Use of these regional predictions for a stream can be complex and often requires the user to determine a number of basin characteristics that may require interpretation. Basin characteristics may include drainage area, classifiers for physical properties, climatic characteristics, and other inputs. Obtaining these input values for gaged and ungaged locations traditionally has been time consuming, subjective, and can lead to inconsistent results.

  16. Signal environment mapping of the Automatic Identification System frequencies from space

    NASA Astrophysics Data System (ADS)

    Skauen, Andreas Nordmo; Olsen, Øystein

    2016-02-01

    This paper presents received signal strength data recorded by the NORAIS Receiver on the four VHF channels allocated to the use of the Automatic Identification System (AIS). The NORAIS Receiver operated on-board the Columbus module of the International Space Station from June 2010 to February 2015. The data shows that a space-based AIS receiver must handle transient strong signals from land-based interference and that the effectiveness of the two long range AIS channels recently allocated is severely reduced in select areas due to land based interference.

  17. Efficiency of the cross-correlation statistic for gravitational wave stochastic background signals with non-Gaussian noise and heterogeneous detector sensitivities

    NASA Astrophysics Data System (ADS)

    Martellini, Lionel; Regimbau, Tania

    2015-11-01

    Under standard assumptions including stationary and serially uncorrelated Gaussian gravitational wave stochastic background signal and noise distributions, as well as homogenous detector sensitivities, the standard cross-correlation detection statistic is known to be optimal in the sense of minimizing the probability of a false dismissal at a fixed value of the probability of a false alarm. The focus of this paper is to analyze the comparative efficiency of this statistic, vs a simple alternative statistic obtained by cross-correlating the squared measurements, in situations that deviate from such standard assumptions. We find that differences in detector sensitivities have a large impact on the comparative efficiency of the cross-correlation detection statistic, which is dominated by the alternative statistic when these differences reach 1 order of magnitude. This effect holds even when both the signal and noise distributions are Gaussian. While the presence of non-Gaussian signals has no material impact for reasonable parameter values, the relative inefficiency of the cross-correlation statistic is less prominent for fat-tailed noise distributions, but it is magnified in case noise distributions have skewness parameters of opposite signs. Our results suggest that introducing an alternative detection statistic can lead to noticeable sensitivity gains when noise distributions are possibly non-Gaussian and/or when detector sensitivities exhibit substantial differences, a situation that is expected to hold in joint detections from Advanced LIGO and Advanced Virgo, in particular in the early phases of development of the detectors, or in joint detections from Advanced LIGO and the Einstein Telescope.

  18. Statistical parametric mapping of stimuli-evoked changes in quantitative blood flow using extended-focus optical coherence microscopy (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Marchand, Paul J.; Bouwens, Arno; Shamaei, Vincent; Nguyen, David; Extermann, Jerome; Bolmont, Tristan; Lasser, Theo

    2016-03-01

    Magnetic Resonance Imaging has revolutionised our understanding of brain function through its ability to image human cerebral structures non-invasively over the entire brain. By exploiting the different magnetic properties of oxygenated and deoxygenated blood, functional MRI can indirectly map areas undergoing neural activation. Alongside the development of fMRI, powerful statistical tools have been developed in an effort to shed light on the neural pathways involved in processing of sensory and cognitive information. In spite of the major improvements made in fMRI technology, the obtained spatial resolution of hundreds of microns prevents MRI in resolving and monitoring processes occurring at the cellular level. In this regard, Optical Coherence Microscopy is an ideal instrumentation as it can image at high spatio-temporal resolution. Moreover, by measuring the mean and the width of the Doppler spectra of light scattered by moving particles, OCM allows extracting the axial and lateral velocity components of red blood cells. The ability to assess quantitatively total blood velocity, as opposed to classical axial velocity Doppler OCM, is of paramount importance in brain imaging as a large proportion of cortical vascular is oriented perpendicularly to the optical axis. We combine here quantitative blood flow imaging with extended-focus Optical Coherence Microscopy and Statistical Parametric Mapping tools to generate maps of stimuli-evoked cortical hemodynamics at the capillary level.

  19. Training signaling pathway maps to biochemical data with constrained fuzzy logic: quantitative analysis of liver cell responses to inflammatory stimuli.

    PubMed

    Morris, Melody K; Saez-Rodriguez, Julio; Clarke, David C; Sorger, Peter K; Lauffenburger, Douglas A

    2011-03-01

    Predictive understanding of cell signaling network operation based on general prior knowledge but consistent with empirical data in a specific environmental context is a current challenge in computational biology. Recent work has demonstrated that Boolean logic can be used to create context-specific network models by training proteomic pathway maps to dedicated biochemical data; however, the Boolean formalism is restricted to characterizing protein species as either fully active or inactive. To advance beyond this limitation, we propose a novel form of fuzzy logic sufficiently flexible to model quantitative data but also sufficiently simple to efficiently construct models by training pathway maps on dedicated experimental measurements. Our new approach, termed constrained fuzzy logic (cFL), converts a prior knowledge network (obtained from literature or interactome databases) into a computable model that describes graded values of protein activation across multiple pathways. We train a cFL-converted network to experimental data describing hepatocytic protein activation by inflammatory cytokines and demonstrate the application of the resultant trained models for three important purposes: (a) generating experimentally testable biological hypotheses concerning pathway crosstalk, (b) establishing capability for quantitative prediction of protein activity, and (c) prediction and understanding of the cytokine release phenotypic response. Our methodology systematically and quantitatively trains a protein pathway map summarizing curated literature to context-specific biochemical data. This process generates a computable model yielding successful prediction of new test data and offering biological insight into complex datasets that are difficult to fully analyze by intuition alone.

  20. Induction of p27Kip1 degradation and anchorage independence by Ras through the MAP kinase signaling pathway.

    PubMed

    Kawada, M; Yamagoe, S; Murakami, Y; Suzuki, K; Mizuno, S; Uehara, Y

    1997-08-01

    While most untransformed cells require substrate attachment for growth (anchorage dependence), the oncogenic transformed cells lack this requirement (anchorage independence) and are often tumorigenic. However, the mechanism of loss of anchorage dependence is not fully understood. When rat normal fibroblasts were cultured in suspension without substrate attachment, the cell cycle arrested in G1 phase and the cyclin-dependent kinase inhibitor p27Kip1 protein and its mRNA accumulated. Conditional expression of oncogenic Ras induced the G1-S transition of the cell cycle and significantly shortened the half-life of p27Kip1 protein without altering its mRNA level. Inhibition of the activation of mitogen-activated protein (MAP) kinase by cyclic AMP-elevating agents and a MEK inhibitor prevented the oncogenic Ras-induced degradation of p27Kip1. These results suggest that the loss of substrate attachment induces the cell cycle arrest through the up-regulation of p27Kip1 mRNA, but the oncogenic Ras confers anchorage independence by accelerating p27Kip1 degradation through the activation of the MAP kinase signaling pathway. Furthermore, we have found that p27Kip1 is phosphorylated by MAP kinase in vitro and the phosphorylated p27Kip1 cannot bind to and inhibit cdk2.

  1. Training Signaling Pathway Maps to Biochemical Data with Constrained Fuzzy Logic: Quantitative Analysis of Liver Cell Responses to Inflammatory Stimuli

    PubMed Central

    Morris, Melody K.; Saez-Rodriguez, Julio; Clarke, David C.; Sorger, Peter K.; Lauffenburger, Douglas A.

    2011-01-01

    Predictive understanding of cell signaling network operation based on general prior knowledge but consistent with empirical data in a specific environmental context is a current challenge in computational biology. Recent work has demonstrated that Boolean logic can be used to create context-specific network models by training proteomic pathway maps to dedicated biochemical data; however, the Boolean formalism is restricted to characterizing protein species as either fully active or inactive. To advance beyond this limitation, we propose a novel form of fuzzy logic sufficiently flexible to model quantitative data but also sufficiently simple to efficiently construct models by training pathway maps on dedicated experimental measurements. Our new approach, termed constrained fuzzy logic (cFL), converts a prior knowledge network (obtained from literature or interactome databases) into a computable model that describes graded values of protein activation across multiple pathways. We train a cFL-converted network to experimental data describing hepatocytic protein activation by inflammatory cytokines and demonstrate the application of the resultant trained models for three important purposes: (a) generating experimentally testable biological hypotheses concerning pathway crosstalk, (b) establishing capability for quantitative prediction of protein activity, and (c) prediction and understanding of the cytokine release phenotypic response. Our methodology systematically and quantitatively trains a protein pathway map summarizing curated literature to context-specific biochemical data. This process generates a computable model yielding successful prediction of new test data and offering biological insight into complex datasets that are difficult to fully analyze by intuition alone. PMID:21408212

  2. Enhanced magnetic flux density mapping using coherent steady state equilibrium signal in MREIT

    NASA Astrophysics Data System (ADS)

    Jeong, Woo Chul; Lee, Mun Bae; Sajib, Saurav Z. K.; Kim, Hyung Joong; Kwon, Oh In; Woo, Eung Je

    2016-03-01

    Measuring the z-component of magnetic flux density B = (Bx, By, Bz) induced by transversally injected current, magnetic resonance electrical impedance tomography (MREIT) aims to visualize electrical property (current density and/or conductivity distribution) in a three-dimensional imaging object. For practical implementations of MREIT technique, it is critical to reduce injection of current pulse within safety requirements. With the goal of minimizing the noise level in measured Bz data, we propose a new method to enhance the measure Bz data using steady-state coherent gradient multi-echo (SSC-GME) MR pulse sequence combining with injection current nonlinear encoding (ICNE) method in MREIT, where the ICNE technique injects current during a readout gradient to maximize the signal intensity of phase signal including Bz. The total phase offset in SSC-GME includes additional magnetic flux density due to the injected current, which is different from the phase signal for the conventional spoiled MR pulse sequence. We decompose the magnetization precession phase from the total phase offset including Bz and optimize Bz data using the steady-state equilibrium signal. Results from a real phantom experiment including different kinds of anomalies demonstrated that the proposed method enhanced Bz comparing to a conventional spoiled pulse sequence.

  3. Mapping erosion susceptibility by a multivariate statistical method: A case study from the Ayvalık region, NW Turkey

    NASA Astrophysics Data System (ADS)

    Akgün, Aykut; Türk, Necdet

    2011-09-01

    Erosion is one of the most important natural hazard phenomena in the world, and it poses a significant threat to Turkey in terms of land degredation and desertification. To cope with this problem, we must determine which areas are erosion-prone. Many studies have been carried out and different models and methods have been used to this end. In this study, we used a logistic regression to prepare an erosion susceptibility map for the Ayvalık region in Balıkesir (NW Turkey). The following were our assessment parameters: weathering grades of rocks, slope gradient, structural lineament density, drainage density, land cover, stream power index (SPI) and profile curvature. These were processed by Idrisi Kilimanjaro GIS software. We used logistic regression analysis to relate predictor variables to the occurrence or non-occurrence of gully erosion sites within geographic cells, and then we used this relationship to produce a probability map for future erosion sites. The results indicate that lineament density, weathering grades of rocks and drainage density are the most important variables governing erosion susceptibility. Other variables, such as land cover and slope gradient, were revealed as secondary important variables. Highly weathered basalt, andesite, basaltic andesite and lacustrine sediments were the units most susceptible to erosion. In order to calculate the prediction accuracy of the erosion susceptibility map generated, we compared it with the map showing the gully erosion areas. On the basis of this comparison, the area under curvature (AUC) value was found to be 0.81. This result suggests that the erosion susceptibility map we generated is accurate.

  4. Recording human electrocorticographic (ECoG) signals for neuroscientific research and real-time functional cortical mapping.

    PubMed

    Hill, N Jeremy; Gupta, Disha; Brunner, Peter; Gunduz, Aysegul; Adamo, Matthew A; Ritaccio, Anthony; Schalk, Gerwin

    2012-01-01

    methods for collecting recording ECoG, and demonstrate how to use these signals for important real-time applications such as clinical mapping and brain-computer interfacing. Our example uses the BCI2000 software platform and the SIGFRIED method, an application for real-time mapping of brain functions. This procedure yields information that clinicians can subsequently use to guide the complex and laborious process of functional mapping by electrical stimulation. PREREQUISITES AND PLANNING: Patients with drug-resistant partial epilepsy may be candidates for resective surgery of an epileptic focus to minimize the frequency of seizures. Prior to resection, the patients undergo monitoring using subdural electrodes for two purposes: first, to localize the epileptic focus, and second, to identify nearby critical brain areas (i.e., eloquent cortex) where resection could result in long-term functional deficits. To implant electrodes, a craniotomy is performed to open the skull. Then, electrode grids and/or strips are placed on the cortex, usually beneath the dura. A typical grid has a set of 8 x 8 platinum-iridium electrodes of 4 mm diameter (2.3 mm exposed surface) embedded in silicon with an inter-electrode distance of 1cm. A strip typically contains 4 or 6 such electrodes in a single line. The locations for these grids/strips are planned by a team of neurologists and neurosurgeons, and are based on previous EEG monitoring, on a structural MRI of the patient's brain, and on relevant factors of the patient's history. Continuous recording over a period of 5-12 days serves to localize epileptic foci, and electrical stimulation via the implanted electrodes allows clinicians to map eloquent cortex. At the end of the monitoring period, explantation of the electrodes and therapeutic resection are performed together in one procedure. In addition to its primary clinical purpose, invasive monitoring also provides a unique opportunity to acquire human ECoG data for neuroscientific research

  5. Recording human electrocorticographic (ECoG) signals for neuroscientific research and real-time functional cortical mapping.

    PubMed

    Hill, N Jeremy; Gupta, Disha; Brunner, Peter; Gunduz, Aysegul; Adamo, Matthew A; Ritaccio, Anthony; Schalk, Gerwin

    2012-06-26

    methods for collecting recording ECoG, and demonstrate how to use these signals for important real-time applications such as clinical mapping and brain-computer interfacing. Our example uses the BCI2000 software platform and the SIGFRIED method, an application for real-time mapping of brain functions. This procedure yields information that clinicians can subsequently use to guide the complex and laborious process of functional mapping by electrical stimulation. PREREQUISITES AND PLANNING: Patients with drug-resistant partial epilepsy may be candidates for resective surgery of an epileptic focus to minimize the frequency of seizures. Prior to resection, the patients undergo monitoring using subdural electrodes for two purposes: first, to localize the epileptic focus, and second, to identify nearby critical brain areas (i.e., eloquent cortex) where resection could result in long-term functional deficits. To implant electrodes, a craniotomy is performed to open the skull. Then, electrode grids and/or strips are placed on the cortex, usually beneath the dura. A typical grid has a set of 8 x 8 platinum-iridium electrodes of 4 mm diameter (2.3 mm exposed surface) embedded in silicon with an inter-electrode distance of 1cm. A strip typically contains 4 or 6 such electrodes in a single line. The locations for these grids/strips are planned by a team of neurologists and neurosurgeons, and are based on previous EEG monitoring, on a structural MRI of the patient's brain, and on relevant factors of the patient's history. Continuous recording over a period of 5-12 days serves to localize epileptic foci, and electrical stimulation via the implanted electrodes allows clinicians to map eloquent cortex. At the end of the monitoring period, explantation of the electrodes and therapeutic resection are performed together in one procedure. In addition to its primary clinical purpose, invasive monitoring also provides a unique opportunity to acquire human ECoG data for neuroscientific research

  6. Mutations in MAP3K7 that Alter the Activity of the TAK1 Signaling Complex Cause Frontometaphyseal Dysplasia.

    PubMed

    Wade, Emma M; Daniel, Philip B; Jenkins, Zandra A; McInerney-Leo, Aideen; Leo, Paul; Morgan, Tim; Addor, Marie Claude; Adès, Lesley C; Bertola, Debora; Bohring, Axel; Carter, Erin; Cho, Tae-Joon; Duba, Hans-Christoph; Fletcher, Elaine; Kim, Chong A; Krakow, Deborah; Morava, Eva; Neuhann, Teresa; Superti-Furga, Andrea; Veenstra-Knol, Irma; Wieczorek, Dagmar; Wilson, Louise C; Hennekam, Raoul C M; Sutherland-Smith, Andrew J; Strom, Tim M; Wilkie, Andrew O M; Brown, Matthew A; Duncan, Emma L; Markie, David M; Robertson, Stephen P

    2016-08-01

    Frontometaphyseal dysplasia (FMD) is a progressive sclerosing skeletal dysplasia affecting the long bones and skull. The cause of FMD in some individuals is gain-of-function mutations in FLNA, although how these mutations result in a hyperostotic phenotype remains unknown. Approximately one half of individuals with FMD have no identified mutation in FLNA and are phenotypically very similar to individuals with FLNA mutations, except for an increased tendency to form keloid scars. Using whole-exome sequencing and targeted Sanger sequencing in 19 FMD-affected individuals with no identifiable FLNA mutation, we identified mutations in two genes-MAP3K7, encoding transforming growth factor β (TGF-β)-activated kinase (TAK1), and TAB2, encoding TAK1-associated binding protein 2 (TAB2). Four mutations were found in MAP3K7, including one highly recurrent (n = 15) de novo mutation (c.1454C>T [ p.Pro485Leu]) proximal to the coiled-coil domain of TAK1 and three missense mutations affecting the kinase domain (c.208G>C [p.Glu70Gln], c.299T>A [p.Val100Glu], and c.502G>C [p.Gly168Arg]). Notably, the subjects with the latter three mutations had a milder FMD phenotype. An additional de novo mutation was found in TAB2 (c.1705G>A, p.Glu569Lys). The recurrent mutation does not destabilize TAK1, or impair its ability to homodimerize or bind TAB2, but it does increase TAK1 autophosphorylation and alter the activity of more than one signaling pathway regulated by the TAK1 kinase complex. These findings show that dysregulation of the TAK1 complex produces a close phenocopy of FMD caused by FLNA mutations. Furthermore, they suggest that the pathogenesis of some of the filaminopathies caused by FLNA mutations might be mediated by misregulation of signaling coordinated through the TAK1 signaling complex. PMID:27426733

  7. Microglial Signaling in Chronic Pain with a Special Focus on Caspase 6, p38 MAP Kinase, and Sex Dependence.

    PubMed

    Berta, T; Qadri, Y J; Chen, G; Ji, R R

    2016-09-01

    Microglia are the resident immune cells in the spinal cord and brain. Mounting evidence suggests that activation of microglia plays an important role in the pathogenesis of chronic pain, including chronic orofacial pain. In particular, microglia contribute to the transition from acute pain to chronic pain, as inhibition of microglial signaling reduces pathologic pain after inflammation, nerve injury, and cancer but not baseline pain. As compared with inflammation, nerve injury induces much more robust morphologic activation of microglia, termed microgliosis, as shown by increased expression of microglial markers, such as CD11b and IBA1. However, microglial signaling inhibitors effectively reduce inflammatory pain and neuropathic pain, arguing against the importance of morphologic activation of microglia in chronic pain sensitization. Importantly, microglia enhance pain states via secretion of proinflammatory and pronociceptive mediators, such as tumor necrosis factor α, interleukins 1β and 18, and brain-derived growth factor. Mechanistically, these mediators have been shown to enhance excitatory synaptic transmission and suppress inhibitory synaptic transmission in the pain circuits. While early studies suggested a predominant role of microglia in the induction of chronic pain, further studies have supported a role of microglia in the maintenance of chronic pain. Intriguingly, recent studies show male-dominant microglial signaling in some neuropathic pain and inflammatory pain states, although both sexes show identical morphologic activation of microglia after nerve injury. In this critical review, we provide evidence to show that caspase 6-a secreted protease that is expressed in primary afferent axonal terminals surrounding microglia-is a robust activator of microglia and induces profound release of tumor necrosis factor α from microglia via activation of p38 MAP kinase. The authors also show that microglial caspase 6/p38 signaling is male dominant in some

  8. Mapping the intramolecular contributions to the inelastic electron tunneling signal of a molecular junction

    NASA Astrophysics Data System (ADS)

    Foti, Giuseppe; Vázquez, Héctor

    2016-07-01

    We present a quantitative analysis of the intramolecular origin of the inelastic electron tunneling signal of a molecular junction. We use density-functional theory to study a representative conjugated molecule with a low degree of symmetry and calculate, for all modes, the different contributions that give rise to the vibrational spectrum. These local contributions involve products of scattering states with electron-phonon matrix elements and thus encode information on both the vibrational modes and the electronic structure. We separate these intra- and interatomic terms and draw a pattern of addition or cancellation of these partial contributions throughout the inelastic spectrum. This allows for a quantitative relation between the degree of symmetry of each vibrational mode, its inelastic signal, and the locality of selection rules.

  9. Macrophage signalling upon mycobacterial infection: the MAP kinases lead the way.

    PubMed

    Schorey, Jeffrey S; Cooper, Andrea M

    2003-03-01

    Mycobacteria activate a series of macrophage signalling pathways upon engaging host cell receptors and during the invasion process. These signals initiate a cascade of events leading to the production of immune effector molecules including cytokines, chemokines and reactive nitrogen intermediates. This response by the macrophage is critical for the control of the mycobacterial infection and, not surprisingly, pathogenic mycobacteria have evolved mechanisms to limit this macrophage activation. Recent data has suggested that macrophages infected with pathogenic compared to non-pathogenic mycobacteria are restricted in their activation of the mitogen activated protein kinase (MAPK) pathways. Mitogen activated protein kinase activation in macrophages appears to play an important role in promoting antimycobacterial activity and in the production of various effector molecules following a mycobacterial infection. Therefore, the ability of pathogenic mycobacteria to limit MAPK activity is likely an important virulence mechanism and may be a potential therapeutic target.

  10. Role played by Disabled-2 in albumin induced MAP Kinase signalling

    SciTech Connect

    Diwakar, Ramaswamy Pearson, Alexander L.; Colville-Nash, Paul; Baines, Deborah L.; Dockrell, Mark E.C.

    2008-02-15

    Albumin has been shown to activate the mitogen activated protein kinase (MAPK) pathway in proximal tubular cells (PTECs) of the kidney. Megalin, the putative receptor for albumin has potential signalling properties. However, the mechanisms by which megalin signals are unclear. The adaptor phosphoprotein Disabled-2 (Dab2) is known to interact with the cytoplasmic tail of megalin and may be involved in albumin-mediated MAPK signalling. In this study, we investigated the role of Dab2 in albumin-mediated MAPK signalling and further studied the role of Dab2 in albumin-induced TGF{beta}-1 secretion, a MAPK dependent event. We used RNA interference to knockdown Dab2 protein abundance in HKC-8 cells a model of human PTECs. Albumin activated ERK1,2 and Elk-1 in a MEK-1 dependent manner and resulted in secretion of TGF{beta}-1. In the absence of albumin, knockdown of Dab2 resulted in a trend towards increase in pERK1,2 consistent with its putative role as an inhibitor of cell proliferation. However albumin-induced ERK1,2 activation was completely abolished by Dab2 knockdown. Dab2 knockdown did not however result in inhibition of albumin-induced TGF{beta}-1 secretion. These results suggest that Dab2 is a ligand dependent bi-directional regulator of ERK1,2 activity by demonstrating that in addition to its more traditional role as an inhibitor of ERK1,2 it may also activate ERK1,2.

  11. Valproate inhibits MAP kinase signalling and cell cycle progression in S. cerevisiae

    PubMed Central

    Desfossés-Baron, Kristelle; Hammond-Martel, Ian; Simoneau, Antoine; Sellam, Adnane; Roberts, Stephen; Wurtele, Hugo

    2016-01-01

    The mechanism of action of valproate (VPA), a widely prescribed short chain fatty acid with anticonvulsant and anticancer properties, remains poorly understood. Here, the yeast Saccharomyces cerevisiae was used as model to investigate the biological consequences of VPA exposure. We found that low pH strongly potentiates VPA-induced growth inhibition. Transcriptional profiling revealed that under these conditions, VPA modulates the expression of genes involved in diverse cellular processes including protein folding, cell wall organisation, sexual reproduction, and cell cycle progression. We further investigated the impact of VPA on selected processes and found that this drug: i) activates markers of the unfolded protein stress response such as Hac1 mRNA splicing; ii) modulates the cell wall integrity pathway by inhibiting the activation of the Slt2 MAP kinase, and synergizes with cell wall stressors such as micafungin and calcofluor white in preventing yeast growth; iii) prevents activation of the Kss1 and Fus3 MAP kinases of the mating pheromone pathway, which in turn abolishes cellular responses to alpha factor; and iv) blocks cell cycle progression and DNA replication. Overall, our data identify heretofore unknown biological responses to VPA in budding yeast, and highlight the broad spectrum of cellular pathways influenced by this chemical in eukaryotes. PMID:27782169

  12. Mapping transverse capillary flow speed using time-varying OCT speckle signals (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Choi, Woo June; Wang, Ruikang K.

    2016-03-01

    We present an optical coherence tomography (OCT) based method for mapping transverse red blood cell (RBC) flow speed at capillary. This OCT velocimetry utilizes a quantitative laser speckle temporal contrast analysis that estimates reliable speckle decorrelation time from the observed speckle contrast, which is related to microcirculatory flow velocity. For capillary speed measurement, we employ a home-built 1.3 µm MHz swept-source OCT (SS-OCT) system that can acquire OCT B-frames at a rate of 1.7 kHz. From the multiple B-frames obtained at the same location, intensity profiles with time-varying OCT speckle contrast are extracted at single capillaries using a capillary binary mask and then the transverse flow speed is calculated by adapting the profiles to the speckle contrast analytic model. Finally, a 3D speed map can be achieved for OCT volume imaging. To validate this method, we perform a systematic study using both phantom and in vivo rodent models. Result shows that our method is effective to measure transverse capillary flow speed.

  13. Opposing actions of TGF{beta} and MAP kinase signaling in undifferentiated hen granulosa cells

    SciTech Connect

    Woods, Dori C.; Haugen, Morgan J.; Johnson, A.L. . E-mail: johnson.128@nd.edu

    2005-10-21

    The present studies were conducted to establish interactions between transforming growth factor (TGF)-{beta} and the epidermal growth factor (EGF) family members, TGF{alpha} and betacellulin (BTC), relative to proliferation and differentiation of granulosa cells in hen ovarian follicles. Results presented demonstrate expression of TGF{beta} isoforms, plus TGF{alpha}, BTC, and ErbB receptors in prehierarchal follicles, thus establishing the potential for autocrine/paracrine signaling and cross-talk within granulosa cells at the onset of differentiation. Treatment with TGF{alpha} or BTC increases levels of TGF{beta}1 mRNA in undifferentiated granulosa cells, while the selective inhibitor of mitogen activated protein kinase signaling, U0126, reverses these effects. Moreover, TGF{beta}1 attenuates c-myc mRNA expression and granulosa cell proliferation, while TGF{alpha} blocks both these inhibitory effects. Collectively, these data provide evidence that EGF family ligands regulate both the expression and biological actions of TGF{beta}1 in hen granulosa cells, and indicate that the timely interaction of these opposing factors is an important modulator of both granulosa cell proliferation and differentiation.

  14. Mapping and signaling of neural pathways involved in the regulation of hydromineral homeostasis

    PubMed Central

    Antunes-Rodrigues, J.; Ruginsk, S.G.; Mecawi, A.S.; Margatho, L.O.; Cruz, J.C.; Vilhena-Franco, T.; Reis, W.L.; Ventura, R.R.; Reis, L.C.; Vivas, L.M.; Elias, L.L.K.

    2013-01-01

    Several forebrain and brainstem neurochemical circuitries interact with peripheral neural and humoral signals to collaboratively maintain both the volume and osmolality of extracellular fluids. Although much progress has been made over the past decades in the understanding of complex mechanisms underlying neuroendocrine control of hydromineral homeostasis, several issues still remain to be clarified. The use of techniques such as molecular biology, neuronal tracing, electrophysiology, immunohistochemistry, and microinfusions has significantly improved our ability to identify neuronal phenotypes and their signals, including those related to neuron-glia interactions. Accordingly, neurons have been shown to produce and release a large number of chemical mediators (neurotransmitters, neurohormones and neuromodulators) into the interstitial space, which include not only classic neurotransmitters, such as acetylcholine, amines (noradrenaline, serotonin) and amino acids (glutamate, GABA), but also gaseous (nitric oxide, carbon monoxide and hydrogen sulfide) and lipid-derived (endocannabinoids) mediators. This efferent response, initiated within the neuronal environment, recruits several peripheral effectors, such as hormones (glucocorticoids, angiotensin II, estrogen), which in turn modulate central nervous system responsiveness to systemic challenges. Therefore, in this review, we shall evaluate in an integrated manner the physiological control of body fluid homeostasis from the molecular aspects to the systemic and integrated responses. PMID:23579631

  15. An Association Map on the Effect of Flavonoids on the Signaling Pathways in Colorectal Cancer.

    PubMed

    Koosha, Sanaz; Alshawsh, Mohammed A; Looi, Chung Yeng; Seyedan, Atefehalsadat; Mohamed, Zahurin

    2016-01-01

    Colorectal cancer (CRC) is the third most common type of cancer in the world, causing thousands of deaths annually. Although chemotherapy is known to be an effective treatment to combat colon cancer, it produces severe side effects. Natural products, on the other hand, appear to generate fewer side effects than do chemotherapeutic drugs. Flavonoids are polyphenolic compounds found in various fruits and vegetables known to possess antioxidant activities, and the literature shows that several of these flavonoids have anti-CRC propertiesFlavonoids are classified into five main subclasses: flavonols, flavanones, flavones, flavan-3-ols, and flavanonols. Of these subclasses, the flavanonols have a minimum effect against CRC, whereas the flavones play an important role. The main targets for the inhibitory effect of flavonoids on CRC signaling pathways are caspase; nuclear factor kappa B; mitogen-activated protein kinase/p38; matrix metalloproteinase (MMP)-2, MMP-7, and MMP-9; p53; β-catenin; cyclin-dependent kinase (CDK)2 and CDK4; and cyclins A, B, D, and E. In this review article, we summarize the in vitro and in vivo studies that have been performed since 2000 on the anti-CRC properties of flavonoids. We also describe the signaling pathways affected by flavonoids that have been found to be involved in CRC. Some flavonoids have the potential to be an effective alternative to chemotherapeutic drugs in the treatment of colon cancer; well-controlled clinical studies should, however, be conducted to support this proposal.

  16. An Association Map on the Effect of Flavonoids on the Signaling Pathways in Colorectal Cancer.

    PubMed

    Koosha, Sanaz; Alshawsh, Mohammed A; Looi, Chung Yeng; Seyedan, Atefehalsadat; Mohamed, Zahurin

    2016-01-01

    Colorectal cancer (CRC) is the third most common type of cancer in the world, causing thousands of deaths annually. Although chemotherapy is known to be an effective treatment to combat colon cancer, it produces severe side effects. Natural products, on the other hand, appear to generate fewer side effects than do chemotherapeutic drugs. Flavonoids are polyphenolic compounds found in various fruits and vegetables known to possess antioxidant activities, and the literature shows that several of these flavonoids have anti-CRC propertiesFlavonoids are classified into five main subclasses: flavonols, flavanones, flavones, flavan-3-ols, and flavanonols. Of these subclasses, the flavanonols have a minimum effect against CRC, whereas the flavones play an important role. The main targets for the inhibitory effect of flavonoids on CRC signaling pathways are caspase; nuclear factor kappa B; mitogen-activated protein kinase/p38; matrix metalloproteinase (MMP)-2, MMP-7, and MMP-9; p53; β-catenin; cyclin-dependent kinase (CDK)2 and CDK4; and cyclins A, B, D, and E. In this review article, we summarize the in vitro and in vivo studies that have been performed since 2000 on the anti-CRC properties of flavonoids. We also describe the signaling pathways affected by flavonoids that have been found to be involved in CRC. Some flavonoids have the potential to be an effective alternative to chemotherapeutic drugs in the treatment of colon cancer; well-controlled clinical studies should, however, be conducted to support this proposal. PMID:27226778

  17. Mapping and signaling of neural pathways involved in the regulation of hydromineral homeostasis.

    PubMed

    Antunes-Rodrigues, J; Ruginsk, S G; Mecawi, A S; Margatho, L O; Cruz, J C; Vilhena-Franco, T; Reis, W L; Ventura, R R; Reis, L C; Vivas, L M; Elias, L L K

    2013-04-01

    Several forebrain and brainstem neurochemical circuitries interact with peripheral neural and humoral signals to collaboratively maintain both the volume and osmolality of extracellular fluids. Although much progress has been made over the past decades in the understanding of complex mechanisms underlying neuroendocrine control of hydromineral homeostasis, several issues still remain to be clarified. The use of techniques such as molecular biology, neuronal tracing, electrophysiology, immunohistochemistry, and microinfusions has significantly improved our ability to identify neuronal phenotypes and their signals, including those related to neuron-glia interactions. Accordingly, neurons have been shown to produce and release a large number of chemical mediators (neurotransmitters, neurohormones and neuromodulators) into the interstitial space, which include not only classic neurotransmitters, such as acetylcholine, amines (noradrenaline, serotonin) and amino acids (glutamate, GABA), but also gaseous (nitric oxide, carbon monoxide and hydrogen sulfide) and lipid-derived (endocannabinoids) mediators. This efferent response, initiated within the neuronal environment, recruits several peripheral effectors, such as hormones (glucocorticoids, angiotensin II, estrogen), which in turn modulate central nervous system responsiveness to systemic challenges. Therefore, in this review, we shall evaluate in an integrated manner the physiological control of body fluid homeostasis from the molecular aspects to the systemic and integrated responses. PMID:23579631

  18. An Association Map on the Effect of Flavonoids on the Signaling Pathways in Colorectal Cancer

    PubMed Central

    Koosha, Sanaz; Alshawsh, Mohammed A.; Looi, Chung Yeng; Seyedan, Atefehalsadat; Mohamed, Zahurin

    2016-01-01

    Colorectal cancer (CRC) is the third most common type of cancer in the world, causing thousands of deaths annually. Although chemotherapy is known to be an effective treatment to combat colon cancer, it produces severe side effects. Natural products, on the other hand, appear to generate fewer side effects than do chemotherapeutic drugs. Flavonoids are polyphenolic compounds found in various fruits and vegetables known to possess antioxidant activities, and the literature shows that several of these flavonoids have anti-CRC propertiesFlavonoids are classified into five main subclasses: flavonols, flavanones, flavones, flavan-3-ols, and flavanonols. Of these subclasses, the flavanonols have a minimum effect against CRC, whereas the flavones play an important role. The main targets for the inhibitory effect of flavonoids on CRC signaling pathways are caspase; nuclear factor kappa B; mitogen-activated protein kinase/p38; matrix metalloproteinase (MMP)-2, MMP-7, and MMP-9; p53; β-catenin; cyclin-dependent kinase (CDK)2 and CDK4; and cyclins A, B, D, and E. In this review article, we summarize the in vitro and in vivo studies that have been performed since 2000 on the anti-CRC properties of flavonoids. We also describe the signaling pathways affected by flavonoids that have been found to be involved in CRC. Some flavonoids have the potential to be an effective alternative to chemotherapeutic drugs in the treatment of colon cancer; well-controlled clinical studies should, however, be conducted to support this proposal. PMID:27226778

  19. Membrane Transfer from Mononuclear Cells to Polymorphonuclear Neutrophils Transduces Cell Survival and Activation Signals in the Recipient Cells via Anti-Extrinsic Apoptotic and MAP Kinase Signaling Pathways

    PubMed Central

    Li, Ko-Jen; Wu, Cheng-Han; Shen, Chieh-Yu; Kuo, Yu-Min; Yu, Chia-Li; Hsieh, Song-Chou

    2016-01-01

    The biological significance of membrane transfer (trogocytosis) between polymorphonuclear neutrophils (PMNs) and mononuclear cells (MNCs) remains unclear. We investigated the biological/immunological effects and molecular basis of trogocytosis among various immune cells in healthy individuals and patients with active systemic lupus erythematosus (SLE). By flow cytometry, we determined that molecules in the immunological synapse, including HLA class-I and-II, CD11b and LFA-1, along with CXCR1, are exchanged among autologous PMNs, CD4+ T cells, and U937 cells (monocytes) after cell-cell contact. Small interfering RNA knockdown of the integrin adhesion molecule CD11a in U937 unexpectedly enhanced the level of total membrane transfer from U937 to PMN cells. Functionally, phagocytosis and IL-8 production by PMNs were enhanced after co-culture with T cells. Total membrane transfer from CD4+ T to PMNs delayed PMN apoptosis by suppressing the extrinsic apoptotic molecules, BAX, MYC and caspase 8. This enhancement of activities of PMNs by T cells was found to be mediated via p38- and P44/42-Akt-MAP kinase pathways and inhibited by the actin-polymerization inhibitor, latrunculin B, the clathrin inhibitor, Pitstop-2, and human immunoglobulin G, but not by the caveolin inhibitor, methyl-β-cyclodextrin. In addition, membrane transfer from PMNs enhanced IL-2 production by recipient anti-CD3/anti-CD28 activated MNCs, and this was suppressed by inhibitors of mitogen-activated protein kinase (PD98059) and protein kinase C (Rottlerin). Of clinical significance, decreased total membrane transfer from PMNs to MNCs in patients with active SLE suppressed mononuclear IL-2 production. In conclusion, membrane transfer from MNCs to PMNs, mainly at the immunological synapse, transduces survival and activation signals to enhance PMN functions and is dependent on actin polymerization, clathrin activation, and Fcγ receptors, while membrane transfer from PMNs to MNCs depends on MAP kinase and

  20. Textural analysis by statistical parameters and its application to the mapping of flow-structures in wetlands

    NASA Technical Reports Server (NTRS)

    Wieczorek, U.

    1977-01-01

    From 1974 to 1977 the application of remote sensing methods in coastal areas and tidal bays and estuaries was investigated on the German coast of the North Sea. Aerial photographs were taken using different films; (1) color, (2) color infrared, and (3) black and white films. Scanner recordings were taken by an 11 channel scanner. Ground truth measurements of radiation and measurements of meteorological elements were carried out. For mapping the morphology in mudflat areas a digital texture analysis was developed, by which measurement of the change of image structures cased by distributing factors, such as changing illumination, is possible.

  1. Modeling the envelope statistics of three-dimensional high-frequency ultrasound echo signals from dissected human lymph nodes.

    PubMed

    Bui, Thanh Minh; Coron, Alain; Mamou, Jonathan; Saegusa-Beecroft, Emi; Yamaguchi, Tadashi; Yanagihara, Eugene; Machi, Junji; Bridal, S Lori; Feleppa, Ernest J

    2014-01-01

    This work investigates the statistics of the envelope of three-dimensional (3D) high-frequency ultrasound (HFU) data acquired from dissected human lymph nodes (LNs). Nine distributions were employed, and their parameters were estimated using the method of moments. The Kolmogorov Smirnov (KS) metric was used to quantitatively compare the fit of each candidate distribution to the experimental envelope distribution. The study indicates that the generalized gamma distribution best models the statistics of the envelope data of the three media encountered: LN parenchyma, fat and phosphate-buffered saline (PBS). Furthermore, the envelope statistics of the LN parenchyma satisfy the pre-Rayleigh condition. In terms of high fitting accuracy and computationally efficient parameter estimation, the gamma distribution is the best choice to model the envelope statistics of LN parenchyma, while, the Weibull distribution is the best choice to model the envelope statistics of fat and PBS. These results will contribute to the development of more-accurate and automatic 3D segmentation of LNs for ultrasonic detection of clinically significant LN metastases.

  2. STEAM - Statistical Template Estimation for Abnormality Mapping: A personalized DTI analysis technique with applications to the screening of preterm infants.

    PubMed

    Booth, Brian G; Miller, Steven P; Brown, Colin J; Poskitt, Kenneth J; Chau, Vann; Grunau, Ruth E; Synnes, Anne R; Hamarneh, Ghassan

    2016-01-15

    We introduce the STEAM DTI analysis engine: a whole brain voxel-based analysis technique for the examination of diffusion tensor images (DTIs). Our STEAM analysis technique consists of two parts. First, we introduce a collection of statistical templates that represent the distribution of DTIs for a normative population. These templates include various diffusion measures from the full tensor, to fractional anisotropy, to 12 other tensor features. Second, we propose a voxel-based analysis (VBA) pipeline that is reliable enough to identify areas in individual DTI scans that differ significantly from the normative group represented in the STEAM statistical templates. We identify and justify choices in the VBA pipeline relating to multiple comparison correction, image smoothing, and dealing with non-normally distributed data. Finally, we provide a proof of concept for the utility of STEAM on a cohort of 134 very preterm infants. We generated templates from scans of 55 very preterm infants whose T1 MRI scans show no abnormalities and who have normal neurodevelopmental outcome. The remaining 79 infants were then compared to the templates using our VBA technique. We show: (a) that our statistical templates display the white matter development expected over the modeled time period, and (b) that our VBA results detect abnormalities in the diffusion measurements that relate significantly with both the presence of white matter lesions and with neurodevelopmental outcomes at 18months. Most notably, we show that STEAM produces personalized results while also being able to highlight abnormalities across the whole brain and at the scale of individual voxels. While we show the value of STEAM on DTI scans from a preterm infant cohort, STEAM can be equally applied to other cohorts as well. To facilitate this whole-brain personalized DTI analysis, we made STEAM publicly available at http://www.sfu.ca/bgb2/steam. PMID:26515903

  3. STEAM - Statistical Template Estimation for Abnormality Mapping: A personalized DTI analysis technique with applications to the screening of preterm infants.

    PubMed

    Booth, Brian G; Miller, Steven P; Brown, Colin J; Poskitt, Kenneth J; Chau, Vann; Grunau, Ruth E; Synnes, Anne R; Hamarneh, Ghassan

    2016-01-15

    We introduce the STEAM DTI analysis engine: a whole brain voxel-based analysis technique for the examination of diffusion tensor images (DTIs). Our STEAM analysis technique consists of two parts. First, we introduce a collection of statistical templates that represent the distribution of DTIs for a normative population. These templates include various diffusion measures from the full tensor, to fractional anisotropy, to 12 other tensor features. Second, we propose a voxel-based analysis (VBA) pipeline that is reliable enough to identify areas in individual DTI scans that differ significantly from the normative group represented in the STEAM statistical templates. We identify and justify choices in the VBA pipeline relating to multiple comparison correction, image smoothing, and dealing with non-normally distributed data. Finally, we provide a proof of concept for the utility of STEAM on a cohort of 134 very preterm infants. We generated templates from scans of 55 very preterm infants whose T1 MRI scans show no abnormalities and who have normal neurodevelopmental outcome. The remaining 79 infants were then compared to the templates using our VBA technique. We show: (a) that our statistical templates display the white matter development expected over the modeled time period, and (b) that our VBA results detect abnormalities in the diffusion measurements that relate significantly with both the presence of white matter lesions and with neurodevelopmental outcomes at 18months. Most notably, we show that STEAM produces personalized results while also being able to highlight abnormalities across the whole brain and at the scale of individual voxels. While we show the value of STEAM on DTI scans from a preterm infant cohort, STEAM can be equally applied to other cohorts as well. To facilitate this whole-brain personalized DTI analysis, we made STEAM publicly available at http://www.sfu.ca/bgb2/steam.

  4. Cumulative fade statistics and prediction methods associated with the COMSTAR beacon signal at 28.56 GHz

    NASA Technical Reports Server (NTRS)

    Goldhirsh, J.

    1978-01-01

    The paper presents cumulative fade statistics for the period April 1977 to March 1978 and reviews the rain attenuation predictive efforts using radar and disdrometer data for the summer of 1977. Attention is given to the receiving and radar systems as well as the disdrometer-raingage system. Discussion of the fade statistics covers the yearly, monthly and time of day statistics. Consideration is given to measured and predicted attenuation events, measured and predicted probability distributions as well as an empirical calibration adjustment. It is noted that in spite of many reasons for noncorrelation, the radar results do correlate well. Finally, it is concluded that the results demonstrate the utility of using radar coupled with disdrometer measurements for predicting individual fade events as well as long term fade distributions associated with satellite communications through rain.

  5. Mapping cell populations in flow cytometry data for cross‐sample comparison using the Friedman–Rafsky test statistic as a distance measure

    PubMed Central

    Hsiao, Chiaowen; Liu, Mengya; Stanton, Rick; McGee, Monnie; Qian, Yu

    2015-01-01

    Abstract Flow cytometry (FCM) is a fluorescence‐based single‐cell experimental technology that is routinely applied in biomedical research for identifying cellular biomarkers of normal physiological responses and abnormal disease states. While many computational methods have been developed that focus on identifying cell populations in individual FCM samples, very few have addressed how the identified cell populations can be matched across samples for comparative analysis. This article presents FlowMap‐FR, a novel method for cell population mapping across FCM samples. FlowMap‐FR is based on the Friedman–Rafsky nonparametric test statistic (FR statistic), which quantifies the equivalence of multivariate distributions. As applied to FCM data by FlowMap‐FR, the FR statistic objectively quantifies the similarity between cell populations based on the shapes, sizes, and positions of fluorescence data distributions in the multidimensional feature space. To test and evaluate the performance of FlowMap‐FR, we simulated the kinds of biological and technical sample variations that are commonly observed in FCM data. The results show that FlowMap‐FR is able to effectively identify equivalent cell populations between samples under scenarios of proportion differences and modest position shifts. As a statistical test, FlowMap‐FR can be used to determine whether the expression of a cellular marker is statistically different between two cell populations, suggesting candidates for new cellular phenotypes by providing an objective statistical measure. In addition, FlowMap‐FR can indicate situations in which inappropriate splitting or merging of cell populations has occurred during gating procedures. We compared the FR statistic with the symmetric version of Kullback–Leibler divergence measure used in a previous population matching method with both simulated and real data. The FR statistic outperforms the symmetric version of KL‐distance in distinguishing

  6. A high performance biometric signal and image processing method to reveal blood perfusion towards 3D oxygen saturation mapping

    NASA Astrophysics Data System (ADS)

    Imms, Ryan; Hu, Sijung; Azorin-Peris, Vicente; Trico, Michaël.; Summers, Ron

    2014-03-01

    Non-contact imaging photoplethysmography (PPG) is a recent development in the field of physiological data acquisition, currently undergoing a large amount of research to characterize and define the range of its capabilities. Contact-based PPG techniques have been broadly used in clinical scenarios for a number of years to obtain direct information about the degree of oxygen saturation for patients. With the advent of imaging techniques, there is strong potential to enable access to additional information such as multi-dimensional blood perfusion and saturation mapping. The further development of effective opto-physiological monitoring techniques is dependent upon novel modelling techniques coupled with improved sensor design and effective signal processing methodologies. The biometric signal and imaging processing platform (bSIPP) provides a comprehensive set of features for extraction and analysis of recorded iPPG data, enabling direct comparison with other biomedical diagnostic tools such as ECG and EEG. Additionally, utilizing information about the nature of tissue structure has enabled the generation of an engineering model describing the behaviour of light during its travel through the biological tissue. This enables the estimation of the relative oxygen saturation and blood perfusion in different layers of the tissue to be calculated, which has the potential to be a useful diagnostic tool.

  7. Empirical validation of statistical parametric mapping for group imaging of fast neural activity using electrical impedance tomography.

    PubMed

    Packham, B; Barnes, G; Dos Santos, G Sato; Aristovich, K; Gilad, O; Ghosh, A; Oh, T; Holder, D

    2016-06-01

    Electrical impedance tomography (EIT) allows for the reconstruction of internal conductivity from surface measurements. A change in conductivity occurs as ion channels open during neural activity, making EIT a potential tool for functional brain imaging. EIT images can have  >10 000 voxels, which means statistical analysis of such images presents a substantial multiple testing problem. One way to optimally correct for these issues and still maintain the flexibility of complicated experimental designs is to use random field theory. This parametric method estimates the distribution of peaks one would expect by chance in a smooth random field of a given size. Random field theory has been used in several other neuroimaging techniques but never validated for EIT images of fast neural activity, such validation can be achieved using non-parametric techniques. Both parametric and non-parametric techniques were used to analyze a set of 22 images collected from 8 rats. Significant group activations were detected using both techniques (corrected p  <  0.05). Both parametric and non-parametric analyses yielded similar results, although the latter was less conservative. These results demonstrate the first statistical analysis of such an image set and indicate that such an analysis is an approach for EIT images of neural activity. PMID:27203477

  8. Statistical mapping of ULF Pc3 velocity fluctuations in the Earth's dayside magnetosheath as a function of solar wind conditions

    NASA Astrophysics Data System (ADS)

    Dimmock, A. P.; Nykyri, K.; Osmane, A.; Pulkkinen, T. I.

    2016-07-01

    In this paper, we present the results of a statistical study of Pc3 velocity fluctuations in the Earth's dayside magnetosheath. There exists a notable dawn-dusk asymmetry, such that velocity fluctuations generally exhibit enhanced spectral power in the magnetosheath downstream of the quasi-parallel shock. The fluctuations in the central magnetosheath and close to bow shock tend to dampen with increasing tail-ward distance while the opposite trend is observed close to the magnetopause. This strongly suggests that velocity shear driven processes such as the Kelvin-Helmholtz instability drive Pc3 flow variations close to the magnetopause as the velocity shear increases with increasing tail-ward distance. We also show strong evidence that Pc3 velocity fluctuations are significantly enhanced during intervals of faster solar wind speeds. We see negligible differences between data collected during northward and southward IMF orientations, but in general, a dawn-favoured asymmetry persists.

  9. Mapping indoor radon-222 in Denmark: design and test of the statistical model used in the second nationwide survey.

    PubMed

    Andersen, C E; Ulbak, K; Damkjaer, A; Kirkegaard, P; Gravesen, P

    2001-05-14

    In Denmark, a new survey of indoor radon-222 has been carried out, 1-year alpha track measurements (CR-39) have been made in 3019 single-family houses. There are from 3 to 23 house measurements in each of the 275 municipalities. Within each municipality, houses have been selected randomly. One important outcome of the survey is the prediction of the fraction of houses in each municipality with an annual average radon concentration above 200 Bq m(-3). To obtain the most accurate estimate and to assess the associated uncertainties, a statistical model has been developed. The purpose of this paper is to describe the design of this model, and to report results of model tests. The model is based on a transformation of the data to normality and on analytical (conditionally) unbiased estimators of the quantities of interest. Bayesian statistics are used to minimize the effect of small sample size. In each municipality, the correction is dependent on the fraction of area where sand and gravel is a dominating surface geology. The uncertainty analysis is done with a Monte-Carlo technique. It is demonstrated that the weighted sum of all municipality model estimates of fractions above 200 Bq m(-3) (3.9% with 95%-confidence interval = [3.4,4.5]) is consistent with the weighted sum of the observations for Denmark taken as a whole (4.6% with 95%-confidence interval = [3.8,5.6]). The total number of single-family houses within each municipality is used as weight. Model estimates are also found to be consistent with observations at the level of individual counties. These typically include a few hundred house measurements. These tests indicate that the model is well suited for its purpose.

  10. Mapping the Dark Matter From UV Light at High Redshift: An Empirical Approach to Understand Galaxy Statistics

    SciTech Connect

    Lee, Kyoung-Soo; Giavalisco, Mauro; Conroy, Charlie; Wechsler, Risa H; Ferguson, Henry C.; Somerville, Rachel S.; Dickinson, Mark E.; Urry, Claudia M.; /Yale Ctr. Astron. Astrophys.

    2009-08-03

    We present a simple formalism to interpret the observations of two galaxy statistics, the UV luminosity function (LF) and two-point correlation functions for star-forming galaxies at z {approx} 4, 5 and 6 in the context of {Lambda}CDM cosmology. Both statistics are the result of how star formation takes place in dark matter halos, and thus are used to constrain how UV light depends on halo properties, in particular halo mass. The two physical quantities we explore are the star formation duty cycle, and the range of UV luminosity that a halo of mass M can have (mean and variance). The former directly addresses the typical duration of star formation activity in halos while the latter addresses the averaged star formation history and regularity of gas inflow into these systems. In the context of this formalism, we explore various physical models consistent with all the available observational data, and find the following: (1) the typical duration of star formation observed in the data is {approx}< 0.4 Gyr (1{sigma}), (2) the inferred scaling law between the observed L{sub UV} and halo mass M from the observed faint-end slope of the luminosity functions is roughly linear out to M {approx} 10{sup 11.5} - 10{sup 12} h{sup -1} M{sub {circle_dot}} at all redshifts probed in this work, and (3) the observed L{sub UV} for a fixed halo mass M decreases with time, implying that the star formation efficiency (after dust extinction) is higher at earlier times. We explore several different physical scenarios relating star formation to halo mass, but find that these scenarios are indistinguishable due to the limited range of halo mass probed by our data. In order to discriminate between different scenarios, we discuss the possibility of using the bright-faint galaxy cross-correlation functions and more robust determination of luminosity-dependent galaxy bias for future surveys.

  11. Statistical Methods for Assessing Changes in Similarity Maps between Locations in Monthly Temperatures and Precipitation over Time

    NASA Astrophysics Data System (ADS)

    Hawkins, L. R.; Greenwood, M. C.

    2013-12-01

    The increase in global average air and ocean temperatures, melting of snow and ice, and the rising global average sea level, confirm that warming of the climate is evident. The rate of warming may vary considerably on the regional scale due to topographical features and other systems interacting with atmospheric circulation. Interdependent ecosystems may be affected by a change in the relationship between climates. We develop a method for assessing temporal changes in the relationships among regional climates. This approach is demonstrated with nineteen weather stations from the USHCN located throughout the Rocky Mountains. We explore the potential to detect changes in relationships among aspects of regional climates across different locations from 1913 to 2012. Temperature and precipitation climate indices are used for creating distance matrices between locations for each decade between 1913 and 2012. Multidimensional Scaling is used to 'map' the similarities/dissimilarities among locations and visualize how relationships change across decades. A matrix of pair-wise Pearson correlations between decadal distance matrices is converted to a distance matrix and analyzed using Distance-Based Permutation MANOVA methods for trends over time. The tests suggest strong evidence for systematic changes in the relationships between these locations over time in monthly minimum, maximum, and average temperature while the evidence is weaker for trends in monthly precipitation. This method can be extended to ecological applications, species distribution modeling and other spatiotemporal studies.

  12. Using ALSM to map sinkholes in the urbanized covered karst of Pinellas County, Florida—2. Accuracy statistics

    NASA Astrophysics Data System (ADS)

    Vacher, H. L.; Seale, Larry D.; Florea, Lee J.; Brinkmann, Robert

    2008-05-01

    We apply the logic of clinical epidemiological studies to quantify the accuracy of mapping sinkholes by ALSM in the 750 km2 Pinellas County. By such studies, a new diagnostic procedure is tested by comparing the diagnoses in a clinical trial to diagnoses on the same patients from a more reliable, but more elaborate and expensive procedure (“gold standard” in epidemiological context). A relatively undeveloped, 65 km2 focus area where we have aerial photographs that are effectively contemporaneous with the ALSM flights serves as the “clinical trial”. The xy-locations in the focus area are the “patients” in the trial. The “diagnostic test” for having “sinkhole disease” is inclusion in a database of sinkhole polygons delimited by ALSM contours (“ALSM-alone”), as detailed in Part 1. The standard of comparison (“gold standard” would be an overstatement in the absence of geophysical testing) is inclusion in a database of sinkhole outlines derived by best judgment of conjunctive interpretation of ALSM and aerial photography. GIS intersections that indicate the sensitivity and specificity of the test (ALSM-alone) are 43 and 98.3%, respectively, and, in the focus area where the prevalence of “sinkhole disease” is 4.7%, the positive and negative predictive values are 55.5 and 97.2%, respectively. Over much of the rest of the county, where only the test can be applied, the prevalence of sinkholes is sufficiently small that it cannot be determined to be any different from zero given the paucity of interpreted sinkholes (positive diagnoses) and the low specificity of the test method. The conclusion, therefore, is that contemporaneous aerial photography is essential to compile an ALSM-derived database that aims to state that the given xy-points lay inside or outside of topographic depressions in the covered karst of west-central Florida.

  13. Assessment of Water Quality in a Subtropical Alpine Lake Using Multivariate Statistical Techniques and Geostatistical Mapping: A Case Study

    PubMed Central

    Liu, Wen-Cheng; Yu, Hwa-Lung; Chung, Chung-En

    2011-01-01

    Concerns about the water quality in Yuan-Yang Lake (YYL), a shallow, subtropical alpine lake located in north-central Taiwan, has been rapidly increasing recently due to the natural and anthropogenic pollution. In order to understand the underlying physical and chemical processes as well as their associated spatial distribution in YYL, this study analyzes fourteen physico-chemical water quality parameters recorded at the eight sampling stations during 2008–2010 by using multivariate statistical techniques and a geostatistical method. Hierarchical clustering analysis (CA) is first applied to distinguish the three general water quality patterns among the stations, followed by the use of principle component analysis (PCA) and factor analysis (FA) to extract and recognize the major underlying factors contributing to the variations among the water quality measures. The spatial distribution of the identified major contributing factors is obtained by using a kriging method. Results show that four principal components i.e., nitrogen nutrients, meteorological factor, turbidity and nitrate factors, account for 65.52% of the total variance among the water quality parameters. The spatial distribution of principal components further confirms that nitrogen sources constitute an important pollutant contribution in the YYL. PMID:21695032

  14. Contour Mapping

    NASA Technical Reports Server (NTRS)

    1995-01-01

    In the early 1990s, the Ohio State University Center for Mapping, a NASA Center for the Commercial Development of Space (CCDS), developed a system for mobile mapping called the GPSVan. While driving, the users can map an area from the sophisticated mapping van equipped with satellite signal receivers, video cameras and computer systems for collecting and storing mapping data. George J. Igel and Company and the Ohio State University Center for Mapping advanced the technology for use in determining the contours of a construction site. The new system reduces the time required for mapping and staking, and can monitor the amount of soil moved.

  15. Investigation of ionospheric TEC changes related to the 2008 Wenchuan earthquake based on statistic analysis and signal detection

    NASA Astrophysics Data System (ADS)

    Li, Jianyong; Meng, Guojie; Wang, Min; Liao, Hua; Shen, Xuhui

    2009-10-01

    Ionospheric TEC (total electron content) time series are derived from GPS measurements at 13 stations around the epicenter of the 2008 Wenchuan earthquake. Defining anomaly bounds for a sliding window by quartile and 2-standard deviation of TEC values, this paper analyzed the characteristics of ionospheric changes before and after the destructive event. The Neyman-Pearson signal detection method is employed to compute the probabilities of TEC abnormalities. Result shows that one week before the Wenchuan earthquake, ionospheric TEC over the epicenter and its vicinities displays obvious abnormal disturbances, most of which are positive anomalies. The largest TEC abnormal changes appeared on May 9, three days prior to the seismic event. Signal detection shows that the largest possibility of TEC abnormity on May 9 is 50.74%, indicating that ionospheric abnormities three days before the main shock are likely related to the preparation process of the M S8.0 Wenchuan earthquake.

  16. Identification and fine mapping of nuclear and nucleolar localization signals within the human ribosomal protein S17.

    PubMed

    Kenney, Scott P; Meng, Xiang-Jin

    2015-01-01

    Human ribosomal protein S17 (RPS17) is mutated in Diamond-Blackfan Anemia (DBA), a bone marrow disorder that fails to produce sufficient red blood cells leading to anemia. Recently, an RPS17 protein sequence was also found to be naturally inserted in the genome of hepatitis E virus (HEV) from patients chronically-infected by HEV. The role of RPS17 in HEV replication and pathogenesis remains unknown due to the lack of knowledge about how RPS17 functions at a molecular level. Understanding the biological function of RPS17 is critical for elucidating its role in virus infection and DBA disease processes. In this study we probed the subcellular distribution of normal and mutant RPS17 proteins in a human liver cell line (Huh7). RPS17 was primarily detected within the nucleus, and more specifically within the nucleoli. Using a transient expression system in which RPS17 or truncations were expressed as fusions with enhanced yellow fluorescent protein (eYFP), we were able to identify and map, for the first time, two separate nuclear localization signals (NLSs), one to the first 13 amino acids of the amino-terminus of RPS17 and the other within amino acids 30-60. Additionally, we mapped amino acid sequences required for nucleolar accumulation of RPS17 to amino acids 60-70. Amino acids 60-70 possess a di-RG motif that may be necessary for nucleolar retention of RPS17. The results from this study enhance our knowledge of RSP17 and will facilitate future mechanistic studies about the roles of RSP17 in hepatitis E and DBA disease processes. PMID:25853866

  17. Statistical signal processing and artificial intelligence applications in the nondestructive assay of U/Pu bearing materials

    SciTech Connect

    Aumeier, S.E.; Forsmann, J.H.

    1997-10-01

    Over the years a number of techniques have been developed to determine the quantity and distribution of radiative isotopes contained in given assay samples through the measurement and analysis of penetrating characteristic radiations. An active technique of particular utility when assaying samples containing very small quantities of fissionable material or when high gamma ray backgrounds are encountered is the delayed neutron nondestructive assay (DN-NDA) technique. Typically, analysis of the delayed neutron signal involves relating the gross delayed neutron count observed following neutron irradiation of an assay sample to total fissionable material present via a linear calibration curve. In this way, the technique is capable of yielding the mass of a single dominant fissionable isotope or the total fissionable mass contained in a sample. Using this approach the only way to determine the mass of individual fissionable isotopes contained in a sample is to correlate total fissionable mass to individual isotopics via calculations or other means, yielding an indirect measure of isotopics. However, there is isotope specific information in the temporal delayed neutron signal due to differences in the delayed neutron precursor yields resulting from the fissioning of different isotopes. The authors present the results of an analysis to evaluate the feasibility of using Kalman filters and genetic algorithms to determine multiple specific fissionable isotopic masses contained in an assay sample from a cumulative delayed neutron signal measured following neutron irradiation of the sample.

  18. miR-625-3p regulates oxaliplatin resistance by targeting MAP2K6-p38 signalling in human colorectal adenocarcinoma cells.

    PubMed

    Rasmussen, Mads Heilskov; Lyskjær, Iben; Jersie-Christensen, Rosa Rakownikow; Tarpgaard, Line Schmidt; Primdal-Bengtson, Bjarke; Nielsen, Morten Muhlig; Pedersen, Jakob Skou; Hansen, Tine Plato; Hansen, Flemming; Olsen, Jesper Velgaard; Pfeiffer, Per; Ørntoft, Torben Falck; Andersen, Claus Lindbjerg

    2016-01-01

    Oxaliplatin resistance in colorectal cancers (CRC) is a major medical problem, and predictive markers are urgently needed. Recently, miR-625-3p was reported as a promising predictive marker. Herein, we show that miR-625-3p functionally induces oxaliplatin resistance in CRC cells, and identify the signalling networks affected by miR-625-3p. We show that the p38 MAPK activator MAP2K6 is a direct target of miR-625-3p, and, accordingly, is downregulated in non-responder patients of oxaliplatin therapy. miR-625-3p-mediated resistance is reversed by anti-miR-625-3p treatment and ectopic expression of a miR-625-3p insensitive MAP2K6 variant. In addition, reduction of p38 signalling by using siRNAs, chemical inhibitors or expression of a dominant-negative MAP2K6 protein induces resistance to oxaliplatin. Transcriptome, proteome and phosphoproteome profiles confirm inactivation of MAP2K6-p38 signalling as one likely mechanism of oxaliplatin resistance. Our study shows that miR-625-3p induces oxaliplatin resistance by abrogating MAP2K6-p38-regulated apoptosis and cell cycle control networks, and corroborates the predictive power of miR-625-3p. PMID:27526785

  19. miR-625-3p regulates oxaliplatin resistance by targeting MAP2K6-p38 signalling in human colorectal adenocarcinoma cells

    PubMed Central

    Rasmussen, Mads Heilskov; Lyskjær, Iben; Jersie-Christensen, Rosa Rakownikow; Tarpgaard, Line Schmidt; Primdal-Bengtson, Bjarke; Nielsen, Morten Muhlig; Pedersen, Jakob Skou; Hansen, Tine Plato; Hansen, Flemming; Olsen, Jesper Velgaard; Pfeiffer, Per; Ørntoft, Torben Falck; Andersen, Claus Lindbjerg

    2016-01-01

    Oxaliplatin resistance in colorectal cancers (CRC) is a major medical problem, and predictive markers are urgently needed. Recently, miR-625-3p was reported as a promising predictive marker. Herein, we show that miR-625-3p functionally induces oxaliplatin resistance in CRC cells, and identify the signalling networks affected by miR-625-3p. We show that the p38 MAPK activator MAP2K6 is a direct target of miR-625-3p, and, accordingly, is downregulated in non-responder patients of oxaliplatin therapy. miR-625-3p-mediated resistance is reversed by anti-miR-625-3p treatment and ectopic expression of a miR-625-3p insensitive MAP2K6 variant. In addition, reduction of p38 signalling by using siRNAs, chemical inhibitors or expression of a dominant-negative MAP2K6 protein induces resistance to oxaliplatin. Transcriptome, proteome and phosphoproteome profiles confirm inactivation of MAP2K6-p38 signalling as one likely mechanism of oxaliplatin resistance. Our study shows that miR-625-3p induces oxaliplatin resistance by abrogating MAP2K6-p38-regulated apoptosis and cell cycle control networks, and corroborates the predictive power of miR-625-3p. PMID:27526785

  20. Method for estimating potential wetland extent by utilizing streamflow statistics and flood-inundation mapping techniques: Pilot study for land along the Wabash River near Terre Haute, Indiana

    USGS Publications Warehouse

    Kim, Moon H.; Ritz, Christian T.; Arvin, Donald V.

    2012-01-01

    Potential wetland extents were estimated for a 14-mile reach of the Wabash River near Terre Haute, Indiana. This pilot study was completed by the U.S. Geological Survey in cooperation with the U.S. Department of Agriculture, Natural Resources Conservation Service (NRCS). The study showed that potential wetland extents can be estimated by analyzing streamflow statistics with the available streamgage data, calculating the approximate water-surface elevation along the river, and generating maps by use of flood-inundation mapping techniques. Planning successful restorations for Wetland Reserve Program (WRP) easements requires a determination of areas that show evidence of being in a zone prone to sustained or frequent flooding. Zone determinations of this type are used by WRP planners to define the actively inundated area and make decisions on restoration-practice installation. According to WRP planning guidelines, a site needs to show evidence of being in an "inundation zone" that is prone to sustained or frequent flooding for a period of 7 consecutive days at least once every 2 years on average in order to meet the planning criteria for determining a wetland for a restoration in agricultural land. By calculating the annual highest 7-consecutive-day mean discharge with a 2-year recurrence interval (7MQ2) at a streamgage on the basis of available streamflow data, one can determine the water-surface elevation corresponding to the calculated flow that defines the estimated inundation zone along the river. By using the estimated water-surface elevation ("inundation elevation") along the river, an approximate extent of potential wetland for a restoration in agricultural land can be mapped. As part of the pilot study, a set of maps representing the estimated potential wetland extents was generated in a geographic information system (GIS) application by combining (1) a digital water-surface plane representing the surface of inundation elevation that sloped in the downstream

  1. MAP KINASE SIGNALING IN PULMONARY FIBROBLASTS EXPOSED TO PARTICULATE MATTER (PM) AND BRONCHOAL VEOLAR LAVAGE FLUID (BALF) FROM HEALTHY AND HYPERTENSIVE RATS

    EPA Science Inventory

    MAP KINASE SIGNALING IN PULMONARY FIBROBLASTS EXPOSED TO PARTICULATE MATTER (PM) AND BRONCHOALVEOLAR LAVAGE FLUID (BALF) FROM HEALTHY AND HYPERTENSIVE RATS. 1P Zhang, UP Kodavanti. NHEERL, US EPA, Research Triangle Park, 1School of Vet Med, NCSU, Raleigh, NC
    Exposure to PM ma...

  2. MAP kinase-signaling controls nuclear translocation of tripeptidyl-peptidase II in response to DNA damage and oxidative stress

    SciTech Connect

    Preta, Giulio; Klark, Rainier de; Chakraborti, Shankhamala; Glas, Rickard

    2010-08-27

    Research highlights: {yields} Nuclear translocation of TPPII occurs in response to different DNA damage inducers. {yields} Nuclear accumulation of TPPII is linked to ROS and anti-oxidant enzyme levels. {yields} MAPKs control nuclear accumulation of TPPII. {yields} Inhibited nuclear accumulation of TPPII decreases DNA damage-induced {gamma}-H2AX expression. -- Abstract: Reactive oxygen species (ROS) are a continuous hazard in eukaroytic cells by their ability to cause damage to biomolecules, in particular to DNA. Previous data indicated that the cytosolic serine peptidase tripeptidyl-peptidase II (TPPII) translocates into the nucleus of most tumor cell lines in response to {gamma}-irradiation and ROS production; an event that promoted p53 expression as well as caspase-activation. We here observed that nuclear translocation of TPPII was dependent on signaling by MAP kinases, including p38MAPK. Further, this was caused by several types of DNA-damaging drugs, a DNA cross-linker (cisplatinum), an inhibitor of topoisomerase II (etoposide), and to some extent also by nucleoside-analogues (5-fluorouracil, hydroxyurea). In the minority of tumor cell lines where TPPII was not translocated into the nucleus in response to DNA damage we observed reduced intracellular ROS levels, and the expression levels of redox defense systems were increased. Further, treatment with the ROS-inducer {gamma}-hexa-chloro-cyclohexane ({gamma}-HCH, lindane), an inhibitor of GAP junctions, restored nuclear translocation of TPPII in these cell lines upon {gamma}-irradiation. Moreover, blocking nuclear translocation of TPPII in etoposide-treated cells, by using a peptide-derived inhibitor (Z-Gly-Leu-Ala-OH), attenuated expression of {gamma}-H2AX in {gamma}-irradiated melanoma cells. Our results indicated a role for TPPII in MAPK-dependent DNA damage signaling.

  3. Regulation of endothelial protein C receptor shedding by cytokines is mediated through differential activation of MAP kinase signaling pathways

    SciTech Connect

    Menschikowski, Mario; Hagelgans, Albert; Eisenhofer, Graeme; Siegert, Gabriele

    2009-09-10

    The endothelial protein C receptor (EPCR) plays a pivotal role in coagulation, inflammation, cell proliferation, and cancer, but its activity is markedly changed by ectodomain cleavage and release as the soluble protein (sEPCR). In this study we examined the mechanisms involved in the regulation of EPCR shedding in human umbilical endothelial cells (HUVEC). Interleukin-1{beta} (IL-1{beta}) and tumor necrosis factor-{alpha} (TNF-{alpha}), but not interferon-{gamma} and interleukin-6, suppressed EPCR mRNA transcription and cell-associated EPCR expression in HUVEC. The release of sEPCR induced by IL-1{beta} and TNF-{alpha} correlated with activation of p38 MAPK and c-Jun N-terminal kinase (JNK). EPCR shedding was also induced by phorbol 12-myristate 13-acetate, ionomycin, anisomycin, thiol oxidants or alkylators, thrombin, and disruptors of lipid rafts. Both basal and induced shedding of EPCR was blocked by the metalloproteinase inhibitors, TAPI-0 and GM6001, and by the reduced non-protein thiols, glutathione, dihydrolipoic acid, dithiothreitol, and N-acetyl-L-cysteine. Because other antioxidants and scavengers of reactive oxygen species failed to block the cleavage of EPCR, a direct suppression of metalloproteinase activity seems responsible for the observed effects of reduced thiols. In summary, the shedding of EPCR in HUVEC is effectively regulated by IL-1{beta} and TNF-{alpha}, and downstream by MAP kinase signaling pathways and metalloproteinases.

  4. [Roles of the cross talk between MAP kinases and Keap1-Nrf2-ARE signaling pathways in chronic obstructive pulmonary disease].

    PubMed

    Wang, Shu-Jun; Chen, Ya-Jun; Wang, Shan-Shan; Wang, Dian-Lei; Wang, Chen-Yin; Yang, Li-Li; Chen, Jin-Pei

    2015-02-01

    Chronic obstructive pulmonary disease (COPD), a common preventable and treatable disease, is characterized by airflow limitation that is usually progressive and associated with an enhanced chronic inflammatory response in the airways. Its main pathological manifestations include airway inflammation, mucus hypersecretion, oxidative stress and apoptotic epithelial cells. Recent research suggests that MAP kinases and Keap1-Nrf2-ARE signaling pathway are involved in the pathological process of inflammation and oxidative stress. This review explores the potential role of the cross talk of these signaling pathways in airway inflammation, mucus hypersecretion, oxidative stress and apoptotic epithelial cells. To clarify the roles of cross talk between MAP kinases and Keap1-Nrf2-ARE signaling pathway, we also focus on the drugs related to that in the treatment of COPD, and it provides ideas for more drug research in the treatment of COPD.

  5. Statistical analysis and mapping of water levels in the Biscayne aquifer, water conservation areas, and Everglades National Park, Miami-Dade County, Florida, 2000–2009

    USGS Publications Warehouse

    Prinos, Scott T.; Dixon, Joann F.

    2016-02-25

    Maps were created by importing site coordinates, summary water-level statistics, and completeness of record statistics into a geographic information system, and by interpolating between water levels at monitoring sites in the canals and water levels along the coastline. Raster surfaces were created from these data by using the triangular irregular network interpolation method. The raster surfaces were contoured by using geographic information system software. These contours were imprecise in some areas because the software could not fully evaluate the hydrology given available information; therefore, contours were manually modified where necessary. The ability to evaluate differences in water levels between 1990–1999 and 2000–2009 is limited in some areas because most of the monitoring sites did not have 80 percent complete records for one or both of these periods. The quality of the analyses was limited by (1) deficiencies in spatial coverage; (2) the combination of pre- and post-construction water levels in areas where canals, levees, retention basins, detention basins, or water-control structures were installed or removed; (3) an inability to address the potential effects of the vertical hydraulic head gradient on water levels in wells of different depths; and (4) an inability to correct for the differences between daily water-level statistics. Contours are dashed in areas where the locations of contours have been approximated because of the uncertainty caused by these limitations. Although the ability of the maps to depict differences in water levels between 1990–1999 and 2000–2009 was limited by missing data, results indicate that near the coast water levels were generally higher in May during 2000–2009 than during 1990–1999; and that inland water levels were generally lower during 2000–2009 than during 1990–1999. Generally, the 25th, 50th, and 75th percentiles of water levels from all months were also higher near the coast and lower inland

  6. Statistical analysis and mapping of water levels in the Biscayne aquifer, water conservation areas, and Everglades National Park, Miami-Dade County, Florida, 2000–2009

    USGS Publications Warehouse

    Prinos, Scott T.; Dixon, Joann F.

    2016-01-01

    Maps were created by importing site coordinates, summary water-level statistics, and completeness of record statistics into a geographic information system, and by interpolating between water levels at monitoring sites in the canals and water levels along the coastline. Raster surfaces were created from these data by using the triangular irregular network interpolation method. The raster surfaces were contoured by using geographic information system software. These contours were imprecise in some areas because the software could not fully evaluate the hydrology given available information; therefore, contours were manually modified where necessary. The ability to evaluate differences in water levels between 1990–1999 and 2000–2009 is limited in some areas because most of the monitoring sites did not have 80 percent complete records for one or both of these periods. The quality of the analyses was limited by (1) deficiencies in spatial coverage; (2) the combination of pre- and post-construction water levels in areas where canals, levees, retention basins, detention basins, or water-control structures were installed or removed; (3) an inability to address the potential effects of the vertical hydraulic head gradient on water levels in wells of different depths; and (4) an inability to correct for the differences between daily water-level statistics. Contours are dashed in areas where the locations of contours have been approximated because of the uncertainty caused by these limitations. Although the ability of the maps to depict differences in water levels between 1990–1999 and 2000–2009 was limited by missing data, results indicate that near the coast water levels were generally higher in May during 2000–2009 than during 1990–1999; and that inland water levels were generally lower during 2000–2009 than during 1990–1999. Generally, the 25th, 50th, and 75th percentiles of water levels from all months were also higher near the coast and lower inland

  7. Statistical signal processing and artificial intelligence applications in the nondestructive assay of U/Pu-bearing materials

    SciTech Connect

    Aumeier, S.E.; Forsmann, J.H.

    1998-09-01

    Over the years, a number of techniques have been developed to determine the quantity and distribution of radiative isotopes contained in given assay samples through the measurement and analysis of penetrating characteristic radiations. An active technique of particular utility when assaying samples containing very small quantities of fissionable material or when high-gamma-ray backgrounds are encountered is the delayed neutron nondestructive assay technique. The authors present the results of an analysis to evaluate the feasibility of using Kalman filters and genetic algorithms to determine multiple specific fissionable isotopic masses contained in an assay sample from a cumulative delayed neutron signal measured following neutron irradiation of the sample. Delayed neutron measurement data were generated to simulate the ideal response of the leached fuel clad monitor located at Argonne National Laboratory-West. The simulated measurement data were generated by calculating the cumulative delayed neutron count following the irradiation of a sample containing 5.9 g {sup 238}U, 9.8 g {sup 235}U, 16.9 G {sup 239}Pu, and 3.1 g {sup 240}Pu. Data were simulated for {approximately} 14-MeV neutron irradiation and irradiation with a moderated neutron beam with average neutron energy of {approximately} 200 eV, which yields a larger fissile/fertile fission ratio than the 14-MeV irradiation.

  8. Induction of Macrophage Function in Human THP-1 Cells Is Associated with Rewiring of MAPK Signaling and Activation of MAP3K7 (TAK1) Protein Kinase

    PubMed Central

    Richter, Erik; Ventz, Katharina; Harms, Manuela; Mostertz, Jörg; Hochgräfe, Falko

    2016-01-01

    Macrophages represent the primary human host response to pathogen infection and link the immediate defense to the adaptive immune system. Mature tissue macrophages convert from circulating monocyte precursor cells by terminal differentiation in a process that is not fully understood. Here, we analyzed the protein kinases of the human monocytic cell line THP-1 before and after induction of macrophage differentiation by using kinomics and phosphoproteomics. When comparing the macrophage-like state with the monocytic precursor, 50% of the kinome was altered in expression and even 71% of covered kinase phosphorylation sites were affected. Kinome rearrangements are for example characterized by a shift of overrepresented cyclin-dependent kinases associated with cell cycle control in monocytes to calmodulin-dependent kinases and kinases involved in proinflammatory signaling. Eventually, we show that monocyte-to-macrophage differentiation is associated with major rewiring of mitogen-activated protein kinase signaling networks and demonstrate that protein kinase MAP3K7 (TAK1) acts as the key signaling hub in bacterial killing, chemokine production and differentiation. Our study proves the fundamental role of protein kinases and cellular signaling as major drivers of macrophage differentiation and function. The finding that MAP3K7 is central to macrophage function suggests MAP3K7 and its networking partners as promising targets in host-directed therapy for macrophage-associated disease. PMID:27066479

  9. The different varieties of the Suyama-Yamaguchi consistency relation and its violation as a signal of statistical inhomogeneity

    SciTech Connect

    Rodríguez, Yeinzon; Almeida, Juan P. Beltrán; Valenzuela-Toledo, César A. E-mail: juanpbeltran@uan.edu.co

    2013-04-01

    We present the different consistency relations that can be seen as variations of the well known Suyama-Yamaguchi (SY) consistency relation τ{sub NL}≥((6/5)f{sub NL}){sup 2}, the latter involving the levels of non-gaussianity f{sub NL} and τ{sub NL} in the primordial curvature perturbation ζ. It has been (implicitly) claimed that the following variation: τ{sub NL}(k{sub 1},k{sub 3})≥((6/5)){sup 2}f{sub NL}(k{sub 1})f{sub NL}(k{sub 3}), which we call ''the fourth variety'', in the collapsed (for τ{sub NL}) and squeezed (for f{sub NL}) limits is always satisfied independently of any physics; however, the proof depends sensitively on the assumption of scale-invariance (expressing this way the fourth variety of the SY consistency relation as τ{sub NL}≥((6/5)f{sub NL}){sup 2}) which only applies for cosmological models involving Lorentz-invariant scalar fields (at least at tree level), leaving room for a strong violation of this variety of the consistency relation when non-trivial degrees of freedom, for instance vector fields, are in charge of the generation of the primordial curvature perturbation. With this in mind as a motivation, we explicitly state, in the first part of this work, under which conditions the SY consistency relation has been claimed to hold in its different varieties (implicitly) presented in the literature since its inception back in 2008; as a result, we show for the first time that the variety τ{sub NL}(k{sub 1},k{sub 1})≥((6/5)f{sub NL}(k{sub 1})){sup 2}, which we call ''the fifth variety'', is always satisfied even when there is strong scale-dependence and high levels of statistical anisotropy as long as statistical homogeneity holds: thus, an observed violation of this specific variety would prevent the comparison between theory and observation, shaking this way the foundations of cosmology as a science. In the second part, we concern about the existence of non-trivial degrees of freedom, concretely vector fields for which the

  10. The different varieties of the Suyama-Yamaguchi consistency relation and its violation as a signal of statistical inhomogeneity

    NASA Astrophysics Data System (ADS)

    Rodríguez, Yeinzon; Beltrán Almeida, Juan P.; Valenzuela-Toledo, César A.

    2013-04-01

    We present the different consistency relations that can be seen as variations of the well known Suyama-Yamaguchi (SY) consistency relation τNL>=((6/5)fNL)2, the latter involving the levels of non-gaussianity fNL and τNL in the primordial curvature perturbation ζ. It has been (implicitly) claimed that the following variation: τNL(k1,k3)>=((6/5))2fNL(k1)fNL(k3), which we call ``the fourth variety'', in the collapsed (for τNL) and squeezed (for fNL) limits is always satisfied independently of any physics; however, the proof depends sensitively on the assumption of scale-invariance (expressing this way the fourth variety of the SY consistency relation as τNL>=((6/5)fNL)2) which only applies for cosmological models involving Lorentz-invariant scalar fields (at least at tree level), leaving room for a strong violation of this variety of the consistency relation when non-trivial degrees of freedom, for instance vector fields, are in charge of the generation of the primordial curvature perturbation. With this in mind as a motivation, we explicitly state, in the first part of this work, under which conditions the SY consistency relation has been claimed to hold in its different varieties (implicitly) presented in the literature since its inception back in 2008; as a result, we show for the first time that the variety τNL(k1,k1)>=((6/5)fNL(k1))2, which we call ``the fifth variety'', is always satisfied even when there is strong scale-dependence and high levels of statistical anisotropy as long as statistical homogeneity holds: thus, an observed violation of this specific variety would prevent the comparison between theory and observation, shaking this way the foundations of cosmology as a science. In the second part, we concern about the existence of non-trivial degrees of freedom, concretely vector fields for which the levels of non-gaussianity have been calculated for very few models; among them, and by making use of the δN formalism at tree level, we study a class

  11. Proper Use of Allele-Specific Expression Improves Statistical Power for cis-eQTL Mapping with RNA-Seq Data

    PubMed Central

    HU, Yi-Juan; SUN, Wei; TZENG, Jung-Ying; PEROU, Charles M.

    2015-01-01

    Studies of expression quantitative trait loci (eQTLs) offer insight into the molecular mechanisms of loci that were found to be associated with complex diseases and the mechanisms can be classified into cis- and trans-acting regulation. At present, high-throughput RNA sequencing (RNA-seq) is rapidly replacing expression microarrays to assess gene expression abundance. Unlike microarrays that only measure the total expression of each gene, RNA-seq also provides information on allele-specific expression (ASE), which can be used to distinguish cis-eQTLs from trans-eQTLs and, more importantly, enhance cis-eQTL mapping. However, assessing the cis-effect of a candidate eQTL on a gene requires knowledge of the haplotypes connecting the candidate eQTL and the gene, which cannot be inferred with certainty. The existing two-stage approach that first phases the candidate eQTL against the gene and then treats the inferred phase as observed in the association analysis tends to attenuate the estimated cis-effect and reduce the power for detecting a cis-eQTL. In this article, we provide a maximum-likelihood framework for cis-eQTL mapping with RNA-seq data. Our approach integrates the inference of haplotypes and the association analysis into a single stage, and is thus unbiased and statistically powerful. We also develop a pipeline for performing a comprehensive scan of all local eQTLs for all genes in the genome by controlling for false discovery rate, and implement the methods in a computationally efficient software program. The advantages of the proposed methods over the existing ones are demonstrated through realistic simulation studies and an application to empirical breast cancer data from The Cancer Genome Atlas project. PMID:26568645

  12. Quantitative estimation of Tropical Rainfall Mapping Mission precipitation radar signals from ground-based polarimetric radar observations

    NASA Astrophysics Data System (ADS)

    Bolen, Steven M.; Chandrasekar, V.

    2003-06-01

    The Tropical Rainfall Mapping Mission (TRMM) is the first mission dedicated to measuring rainfall from space using radar. The precipitation radar (PR) is one of several instruments aboard the TRMM satellite that is operating in a nearly circular orbit with nominal altitude of 350 km, inclination of 35°, and period of 91.5 min. The PR is a single-frequency Ku-band instrument that is designed to yield information about the vertical storm structure so as to gain insight into the intensity and distribution of rainfall. Attenuation effects on PR measurements, however, can be significant and as high as 10-15 dB. This can seriously impair the accuracy of rain rate retrieval algorithms derived from PR signal returns. Quantitative estimation of PR attenuation is made along the PR beam via ground-based polarimetric observations to validate attenuation correction procedures used by the PR. The reflectivity (Zh) at horizontal polarization and specific differential phase (Kdp) are found along the beam from S-band ground radar measurements, and theoretical modeling is used to determine the expected specific attenuation (k) along the space-Earth path at Ku-band frequency from these measurements. A theoretical k-Kdp relationship is determined for rain when Kdp ≥ 0.5°/km, and a power law relationship, k = a Zhb, is determined for light rain and other types of hydrometers encountered along the path. After alignment and resolution volume matching is made between ground and PR measurements, the two-way path-integrated attenuation (PIA) is calculated along the PR propagation path by integrating the specific attenuation along the path. The PR reflectivity derived after removing the PIA is also compared against ground radar observations.

  13. [The blind source separation method based on self-organizing map neural network and convolution kernel compensation for multi-channel sEMG signals].

    PubMed

    Ning, Yong; Zhu, Shan'an; Zhao, Yuming

    2015-02-01

    A new method based on convolution kernel compensation (CKC) for decomposing multi-channel surface electromyogram (sEMG) signals is proposed in this paper. Unsupervised learning and clustering function of self-organizing map (SOM) neural network are employed in this method. An initial innervations pulse train (IPT) is firstly estimated, some time instants corresponding to the highest peaks from the initial IPT are clustered by SOM neural network. Then the final IPT can be obtained from the observations corresponding to these time instants. In this paper, the proposed method was tested on the simulated signal, the influence of signal to noise ratio (SNR), the number of groups clustered by SOM and the number of highest peaks selected from the initial pulse train on the number of reconstructed sources and the pulse accuracy were studied, and the results show that the proposed approach is effective in decomposing multi-channel sEMG signals. PMID:25997257

  14. MAP3K19 Is a Novel Regulator of TGF-β Signaling That Impacts Bleomycin-Induced Lung Injury and Pulmonary Fibrosis

    PubMed Central

    Franz-Bacon, Karin; DiTirro, Danielle N.; Ly, Tai Wei; Bacon, Kevin B.

    2016-01-01

    Idiopathic pulmonary fibrosis (IPF) is a progressive, debilitating disease for which two medications, pirfenidone and nintedanib, have only recently been approved for treatment. The cytokine TGF-β has been shown to be a central mediator in the disease process. We investigated the role of a novel kinase, MAP3K19, upregulated in IPF tissue, in TGF-β-induced signal transduction and in bleomycin-induced pulmonary fibrosis. MAP3K19 has a very limited tissue expression, restricted primarily to the lungs and trachea. In pulmonary tissue, expression was predominantly localized to alveolar and interstitial macrophages, bronchial epithelial cells and type II pneumocytes of the epithelium. MAP3K19 was also found to be overexpressed in bronchoalveolar lavage macrophages from IPF patients compared to normal patients. Treatment of A549 or THP-1 cells with either MAP3K19 siRNA or a highly potent and specific inhibitor reduced phospho-Smad2 & 3 nuclear translocation following TGF-β stimulation. TGF-β-induced gene transcription was also strongly inhibited by both the MAP3K19 inhibitor and nintedanib, whereas pirfenidone had a much less pronounced effect. In combination, the MAP3K19 inhibitor appeared to act synergistically with either pirfenidone or nintedanib, at the level of target gene transcription or protein production. Finally, in an animal model of IPF, inhibition of MAP3K19 strongly attenuated bleomycin-induced pulmonary fibrosis when administered either prophylactically ortherapeutically. In summary, these results strongly suggest that inhibition of MAP3K19 may have a beneficial therapeutic effect in the treatment of IPF and represents a novel strategy to target this disease. PMID:27144281

  15. The role of mitogen-activated protein (MAP) kinase signalling components and the Ste12 transcription factor in germination and pathogenicity of Botrytis cinerea.

    PubMed

    Schamber, Astrid; Leroch, Michaela; Diwo, Janine; Mendgen, Kurt; Hahn, Matthias

    2010-01-01

    In all fungi studied so far, mitogen-activated protein (MAP) kinase cascades serve as central signalling complexes that are involved in various aspects of growth, stress response and infection. In this work, putative components of the yeast Fus3/Kss1-type MAP kinase cascade and the putative downstream transcription factor Ste12 were analysed in the grey mould fungus Botrytis cinerea. Deletion mutants of the MAP triple kinase Ste11, the MAP kinase kinase Ste7 and the MAP kinase adaptor protein Ste50 all resulted in phenotypes similar to that of the previously described BMP1 MAP kinase mutant, namely defects in germination, delayed vegetative growth, reduced size of conidia, lack of sclerotia formation and loss of pathogenicity. Mutants lacking Ste12 showed normal germination, but delayed infection as a result of low penetration efficiency. Two differently spliced ste12 transcripts were detected, and both were able to complement the ste12 mutant, except for a defect in sclerotium formation, which was only corrected by the full-sized transcript. Overexpression of the smaller ste12 transcript resulted in delayed germination and strongly reduced infection. Bc-Gas2, a homologue of Magnaporthe grisea Gas2 that is required for appressorial function, was found to be non-essential for growth and infection, but its expression was under the control of both Bmp1 and Ste12. In summary, the role and regulatory connections of the Fus3/Kss1-type MAP kinase cascade in B. cinerea revealed both common and unique properties compared with those of other plant pathogenic fungi, and provide evidence for a regulatory link between the BMP1 MAP kinase cascade and Ste12. PMID:20078780

  16. Development and aging of superficial white matter myelin from young adulthood to old age: Mapping by vertex-based surface statistics (VBSS).

    PubMed

    Wu, Minjie; Kumar, Anand; Yang, Shaolin

    2016-05-01

    Superficial white matter (SWM) lies immediately beneath cortical gray matter and consists primarily of short association fibers. The characteristics of SWM and its development and aging were seldom examined in the literature and warrant further investigation. Magnetization transfer imaging is sensitive to myelin changes in the white matter. Using an innovative multimodal imaging analysis approach, vertex-based surface statistics (VBSS), the current study vertexwise mapped age-related changes of magnetization transfer ratio (MTR) in SWM from young adulthood to old age (30-85 years, N = 66). Results demonstrated regionally selective and temporally heterochronologic changes of SWM MTR with age, including (1) inverted U-shaped trajectories of SWM MTR in the rostral middle frontal, medial temporal, and temporoparietal regions, suggesting continuing myelination and protracted maturation till age 40-50 years and accelerating demyelination at age 60 and beyond, (2) linear decline of SWM MTR in the middle and superior temporal, and pericalcarine areas, indicating early maturation and less acceleration in age-related degeneration, and (3) no significant changes of SWM MTR in the primary motor, somatosensory and auditory regions, suggesting resistance to age-related deterioration. We did not observe similar patterns of changes in cortical thickness in our sample, suggesting the observed SWM MTR changes are not due to cortical atrophy. Hum Brain Mapp 37:1759-1769, 2016. © 2016 Wiley Periodicals, Inc.

  17. Development and aging of superficial white matter myelin from young adulthood to old age: Mapping by vertex-based surface statistics (VBSS).

    PubMed

    Wu, Minjie; Kumar, Anand; Yang, Shaolin

    2016-05-01

    Superficial white matter (SWM) lies immediately beneath cortical gray matter and consists primarily of short association fibers. The characteristics of SWM and its development and aging were seldom examined in the literature and warrant further investigation. Magnetization transfer imaging is sensitive to myelin changes in the white matter. Using an innovative multimodal imaging analysis approach, vertex-based surface statistics (VBSS), the current study vertexwise mapped age-related changes of magnetization transfer ratio (MTR) in SWM from young adulthood to old age (30-85 years, N = 66). Results demonstrated regionally selective and temporally heterochronologic changes of SWM MTR with age, including (1) inverted U-shaped trajectories of SWM MTR in the rostral middle frontal, medial temporal, and temporoparietal regions, suggesting continuing myelination and protracted maturation till age 40-50 years and accelerating demyelination at age 60 and beyond, (2) linear decline of SWM MTR in the middle and superior temporal, and pericalcarine areas, indicating early maturation and less acceleration in age-related degeneration, and (3) no significant changes of SWM MTR in the primary motor, somatosensory and auditory regions, suggesting resistance to age-related deterioration. We did not observe similar patterns of changes in cortical thickness in our sample, suggesting the observed SWM MTR changes are not due to cortical atrophy. Hum Brain Mapp 37:1759-1769, 2016. © 2016 Wiley Periodicals, Inc. PMID:26955787

  18. A review of ocean color remote sensing methods and statistical techniques for the detection, mapping and analysis of phytoplankton blooms in coastal and open oceans

    NASA Astrophysics Data System (ADS)

    Blondeau-Patissier, David; Gower, James F. R.; Dekker, Arnold G.; Phinn, Stuart R.; Brando, Vittorio E.

    2014-04-01

    The need for more effective environmental monitoring of the open and coastal ocean has recently led to notable advances in satellite ocean color technology and algorithm research. Satellite ocean color sensors' data are widely used for the detection, mapping and monitoring of phytoplankton blooms because earth observation provides a synoptic view of the ocean, both spatially and temporally. Algal blooms are indicators of marine ecosystem health; thus, their monitoring is a key component of effective management of coastal and oceanic resources. Since the late 1970s, a wide variety of operational ocean color satellite sensors and algorithms have been developed. The comprehensive review presented in this article captures the details of the progress and discusses the advantages and limitations of the algorithms used with the multi-spectral ocean color sensors CZCS, SeaWiFS, MODIS and MERIS. Present challenges include overcoming the severe limitation of these algorithms in coastal waters and refining detection limits in various oceanic and coastal environments. To understand the spatio-temporal patterns of algal blooms and their triggering factors, it is essential to consider the possible effects of environmental parameters, such as water temperature, turbidity, solar radiation and bathymetry. Hence, this review will also discuss the use of statistical techniques and additional datasets derived from ecosystem models or other satellite sensors to characterize further the factors triggering or limiting the development of algal blooms in coastal and open ocean waters.

  19. New model of retinocollicular mapping predicts the mechanisms of axonal competition and explains the role of reverse molecular signaling during development.

    PubMed Central

    Grimbert, François; Cang, Jianhua

    2012-01-01

    Precise connections in the brain result from elaborate processes during development. In the visual system, axonal projections from retinal ganglion cells (RGCs) onto the superior colliculus (SC) form a precise retinotopic map. Studies have revealed that the development of retinocollicular maps involves three main factors: graded expression of molecular guidance cues such as EphAs and ephrin-As, activity-dependent processes driven by spontaneous activity in RGCs, and different forms of axonal competition. In this study, we develop a new, versatile model including these factors. We first model the selective arborization of RGC axons, mediated by EphA/ephrin-A signaling, without assuming that this initial process instructs the map's final topology. We also derive an integro-differential equation modeling a second, dynamic phase where activity-dependent plasticity of axonal arbors combined with their competition for collicular resources can deeply remodel the topology of immature maps. Our model hence challenges the view that retinotopic maps are instructed by matching molecular gradients and then merely refined by activity-dependent processes. We reproduce fine features of retinototopic map development in wild type and various transgenic mice, allowing a new understanding of the underlying mechanisms. Our model predicts that competition is not based on comparisons of axonal EphA receptor levels, but rather relies on the optimization of collicular resources mediated by neurotrophic receptors such as p75NTR. Our model finally clarifies the elusive role of reverse signaling between retinal ephrin-As and collicular EphAs by reproducing for the first time the phenotypes of two mouse genotypes where this function is altered. PMID:22787061

  20. Mapping of the Signal Peptide-Binding Domain of Escherichia coli SecA Using Förster Resonance Energy Transfer†

    PubMed Central

    Auclair, Sarah M.; Moses, Julia P.; Musial-Siwek, Monika; Kendall, Debra A.; Oliver, Donald B.; Mukerji, Ishita

    2010-01-01

    Identification of the signal peptide-binding domain within SecA ATPase is an important goal for understanding the molecular basis of SecA preprotein recognition as well as elucidating the chemo-mechanical cycle of this nanomotor during protein translocation. In this study, Förster resonance energy transfer methodology was employed to map the location of the SecA signal peptide-binding domain using a collection of functional monocysteine SecA mutants and alkaline phosphatase signal peptides labeled with appropriate donor–acceptor fluorophores. Fluorescence anisotropy measurements yielded an equilibrium binding constant of 1.4 or 10.7 μM for the alkaline phosphatase signal peptide labeled at residue 22 or 2, respectively, with SecA, and a binding stoichiometry of one signal peptide bound per SecA monomer. Binding affinity measurements performed with a monomer-biased mutant indicate that the signal peptide binds equally well to SecA monomer or dimer. Distance measurements determined for 13 SecA mutants show that the SecA signal peptide-binding domain encompasses a portion of the preprotein cross-linking domain but also includes regions of nucleotide-binding domain 1 and particularly the helical scaffold domain. The identified region lies at a multidomain interface within the heart of SecA, surrounded by and potentially responsive to domains important for binding nucleotide, mature portions of the preprotein, and the SecYEG channel. Our FRET-mapped binding domain, in contrast to the domain identified by NMR spectroscopy, includes the two-helix finger that has been shown to interact with the preprotein during translocation and lies at the entrance to the protein-conducting channel in the recently determined SecA–SecYEG structure. PMID:20025247

  1. Real-time dynamic range and signal to noise enhancement in beam-scanning microscopy by integration of sensor characteristics, data acquisition hardware, and statistical methods

    PubMed Central

    Kissick, David J.; Muir, Ryan D.; Sullivan, Shane Z.; Oglesbee, Robert A.; Simpson, Garth J.

    2014-01-01

    Despite the ubiquitous use of multi-photon and confocal microscopy measurements in biology, the core techniques typically suffer from fundamental compromises between signal to noise (S/N) and linear dynamic range (LDR). In this study, direct synchronous digitization of voltage transients coupled with statistical analysis is shown to allow S/N approaching the theoretical maximum throughout an LDR spanning more than 8 decades, limited only by the dark counts of the detector on the low end and by the intrinsic nonlinearities of the photomultiplier tube (PMT) detector on the high end. Synchronous digitization of each voltage transient represents a fundamental departure from established methods in confocal/multi-photon imaging, which are currently based on either photon counting or signal averaging. High information-density data acquisition (up to 3.2 GB/s of raw data) enables the smooth transition between the two modalities on a pixel-by-pixel basis and the ultimate writing of much smaller files (few kB/s). Modeling of the PMT response allows extraction of key sensor parameters from the histogram of voltage peak-heights. Applications in second harmonic generation (SHG) microscopy are described demonstrating S/N approaching the shot-noise limit of the detector over large dynamic ranges. PMID:24817799

  2. Statistical analysis of dust signals observed by ROSINA/COPS onboard of the Rosetta spacecraft at comet 67P/Churyumov-Gerasimenko

    NASA Astrophysics Data System (ADS)

    Tzou, Chia-Yu; altwegg, kathrin; Bieler, Andre; Calmonte, Ursina; Gasc, Sébastien; Le Roy, Léna; Rubin, Martin

    2016-10-01

    ROSINA is the in situ Rosetta Orbiter Spectrometer for Ion and Neutral Analysis on board of Rosetta, one of the corner stone missions of the European Space Agency (ESA) to land and orbit the Jupiter family comet 67P/Churyumov-Gerasimenko (67P). ROSINA consists of two mass spectrometers and a pressure sensor. The Reflectron Time of Flight Spectrometer (RTOF) and the Double Focusing Mass Spectrometer (DFMS) complement each other in mass and time resolution.The Comet Pressure Sensor (COPS) provides density measurements of the neutral molecules in the cometary coma of 67P. COPS has two gauges, a nude gauge that measures the total neutral density and a ram gauge that measures the dynamic pressure from the comet. Combining the two COPS is also capable of providing gas dynamic information such as gas velocity and gas temperature of the coma.While Rosetta started orbiting around 67P in August 2014, COPS observed diurnal and seasonal variations of the neutral gas density in the coma. Surprisingly, additional to these major density variation patterns, COPS occasionally observed small spikes in the density that are associated with dust. These dust signals can be interpreted as a result of cometary dust releasing volatiles while heated up near COPS. A statistical analysis of dust signals detected by COPS will be presented.

  3. Statistical Analysis of Physiological Signals

    NASA Astrophysics Data System (ADS)

    Ruiz, María G.; Pérez, Leticia

    2003-07-01

    In spite of two hundred years of clinical practice, Homeopathy still lacks of scientific basis. Its fundamental laws, similia principle and the activity of the denominated ultra-high dilutions are controversial issues that do not fit into the mainstream medicine or current physical-chemistry field as well. Aside its clinical efficacy, the identification of physical - chemistry parameters, as markers of the homeopathic effect, would allow to construct mathematic models [1], which in turn, could provide clues regarding the involved mechanism.

  4. Nighttime activity of moving objects, their mapping and statistic making, on the example of applying thermal imaging and advanced image processing to the research of nocturnal mammals

    NASA Astrophysics Data System (ADS)

    Pregowski, Piotr; Owadowska, Edyta; Pietrzak, Jan; Zwolenik, Slawomir

    2005-09-01

    The paper presents method of acquiring a new form of statistical information about the changes at scenery, overseen by thermal imaging camera in static configuration. This type of imagers reach uniquely high efficiency during nighttime surveillance and targeting. The technical issue we have solved, resulted from the problem: how to verify the hypothesis that small, nocturnal rodents, like bank voles, use common paths inside their range and that they form a common, rather stable system? Such research has been especially difficult because the mentioned mammals are secretive, move with various speed and due to low contrast to their natural surroundings - as leaves or grass - nearly impossible for other kind of observations from a few meters distance. The main advantage of the elaborated method showed to be both adequately filtered long thermal movies for manual analyses, as well as auto-creation of the synthetic images which present maps of invisible paths and activity of their usage. Additional file with logs describing objects and their dislocations as the ".txt" files allows various, more detailed studies of animal behavior. The obtained results proved that this original method delivers a new, non-invasive, powerful and dynamic concept of solving various ecological problems. Creation of networks consisted of uncooled thermal imagers - of significantly increased availability - with data transmissions to digital centers allows to investigate of moving - particularly heat generated - objects in complete darkness, much wider and much more efficiently than up today. Thus, although our system was elaborated for ecological studies, a similar one can be considered as a tool for chosen tasks in the optical security areas.

  5. PAU/GNSS-R: Implementation, Performance and First Results of a Real-Time Delay-Doppler Map Reflectometer Using Global Navigation Satellite System Signals

    PubMed Central

    Marchan-Hernandez, Juan Fernando; Camps, Adriano; Rodriguez-Alvarez, Nereida; Bosch-Lluis, Xavier; Ramos-Perez, Isaac; Valencia, Enric

    2008-01-01

    Signals from Global Navigation Satellite Systems (GNSS) were originally conceived for position and speed determination, but they can be used as signals of opportunity as well. The reflection process over a given surface modifies the properties of the scattered signal, and therefore, by processing the reflected signal, relevant geophysical data regarding the surface under study (land, sea, ice…) can be retrieved. In essence, a GNSS-R receiver is a multi-channel GNSS receiver that computes the received power from a given satellite at a number of different delay and Doppler bins of the incoming signal. The first approaches to build such a receiver consisted of sampling and storing the scattered signal for later post-processing. However, a real-time approach to the problem is desirable to obtain immediately useful geophysical variables and reduce the amount of data. The use of FPGA technology makes this possible, while at the same time the system can be easily reconfigured. The signal tracking and processing constraints made necessary to fully design several new blocks. The uniqueness of the implemented system described in this work is the capability to compute in real-time Delay-Doppler maps (DDMs) either for four simultaneous satellites or just one, but with a larger number of bins. The first tests have been conducted from a cliff over the sea and demonstrate the successful performance of the instrument to compute DDMs in real-time from the measured reflected GNSS/R signals. The processing of these measurements shall yield quantitative relationships between the sea state (mainly driven by the surface wind and the swell) and the overall DDM shape. The ultimate goal is to use the DDM shape to correct the sea state influence on the L-band brightness temperature to improve the retrieval of the sea surface salinity (SSS).

  6. Trans-ethnic fine-mapping of lipid loci identifies population-specific signals and allelic heterogeneity that increases the trait variance explained.

    PubMed

    Wu, Ying; Waite, Lindsay L; Jackson, Anne U; Sheu, Wayne H-H; Buyske, Steven; Absher, Devin; Arnett, Donna K; Boerwinkle, Eric; Bonnycastle, Lori L; Carty, Cara L; Cheng, Iona; Cochran, Barbara; Croteau-Chonka, Damien C; Dumitrescu, Logan; Eaton, Charles B; Franceschini, Nora; Guo, Xiuqing; Henderson, Brian E; Hindorff, Lucia A; Kim, Eric; Kinnunen, Leena; Komulainen, Pirjo; Lee, Wen-Jane; Le Marchand, Loic; Lin, Yi; Lindström, Jaana; Lingaas-Holmen, Oddgeir; Mitchell, Sabrina L; Narisu, Narisu; Robinson, Jennifer G; Schumacher, Fred; Stančáková, Alena; Sundvall, Jouko; Sung, Yun-Ju; Swift, Amy J; Wang, Wen-Chang; Wilkens, Lynne; Wilsgaard, Tom; Young, Alicia M; Adair, Linda S; Ballantyne, Christie M; Bůžková, Petra; Chakravarti, Aravinda; Collins, Francis S; Duggan, David; Feranil, Alan B; Ho, Low-Tone; Hung, Yi-Jen; Hunt, Steven C; Hveem, Kristian; Juang, Jyh-Ming J; Kesäniemi, Antero Y; Kuusisto, Johanna; Laakso, Markku; Lakka, Timo A; Lee, I-Te; Leppert, Mark F; Matise, Tara C; Moilanen, Leena; Njølstad, Inger; Peters, Ulrike; Quertermous, Thomas; Rauramaa, Rainer; Rotter, Jerome I; Saramies, Jouko; Tuomilehto, Jaakko; Uusitupa, Matti; Wang, Tzung-Dau; Boehnke, Michael; Haiman, Christopher A; Chen, Yii-Der I; Kooperberg, Charles; Assimes, Themistocles L; Crawford, Dana C; Hsiung, Chao A; North, Kari E; Mohlke, Karen L

    2013-03-01

    Genome-wide association studies (GWAS) have identified ~100 loci associated with blood lipid levels, but much of the trait heritability remains unexplained, and at most loci the identities of the trait-influencing variants remain unknown. We conducted a trans-ethnic fine-mapping study at 18, 22, and 18 GWAS loci on the Metabochip for their association with triglycerides (TG), high-density lipoprotein cholesterol (HDL-C), and low-density lipoprotein cholesterol (LDL-C), respectively, in individuals of African American (n = 6,832), East Asian (n = 9,449), and European (n = 10,829) ancestry. We aimed to identify the variants with strongest association at each locus, identify additional and population-specific signals, refine association signals, and assess the relative significance of previously described functional variants. Among the 58 loci, 33 exhibited evidence of association at P<1 × 10(-4) in at least one ancestry group. Sequential conditional analyses revealed that ten, nine, and four loci in African Americans, Europeans, and East Asians, respectively, exhibited two or more signals. At these loci, accounting for all signals led to a 1.3- to 1.8-fold increase in the explained phenotypic variance compared to the strongest signals. Distinct signals across ancestry groups were identified at PCSK9 and APOA5. Trans-ethnic analyses narrowed the signals to smaller sets of variants at GCKR, PPP1R3B, ABO, LCAT, and ABCA1. Of 27 variants reported previously to have functional effects, 74% exhibited the strongest association at the respective signal. In conclusion, trans-ethnic high-density genotyping and analysis confirm the presence of allelic heterogeneity, allow the identification of population-specific variants, and limit the number of candidate SNPs for functional studies. PMID:23555291

  7. Extracellular simian virus 40 induces an ERK/MAP kinase-independent signalling pathway that activates primary response genes and promotes virus entry.

    PubMed

    Dangoria, N S; Breau, W C; Anderson, H A; Cishek, D M; Norkin, L C

    1996-09-01

    Simian virus 40 (SV40) binding to growth-arrested cells activated an intracellular signalling pathway that induced the up-regulation of the primary response genes c-myc, c-jun and c-sis within 30 min and of JE within 90 min. The up-regulation of the primary response genes occurred in the presence of cycloheximide and when UV-inactivated SV40 was adsorbed to cells. SV40 binding did not activate Raf or mitogen-activated protein kinase (MAP/ERK1), or mobilize intracellular Ca2+. The SV40-induced up-regulation of c-myc and c-jun was blocked by the tyrosine kinase inhibitor, genistein, and by the protein kinase C (PKC) inhibitor, calphostin C, but not by expression of the MAP kinase-specific phosphatase, MKP-1. These results suggest that the SV40-induced signalling pathway includes the activities of a tyrosine kinase and a Ca(2+)-independent isoform of PKC, but not of Raf or MAP kinase. Finally, SV40 infectious entry into cells was specifically and reversibly blocked by genistein.

  8. FRET imaging and statistical signal processing reveal positive and negative feedback loops regulating the morphology of randomly migrating HT-1080 cells.

    PubMed

    Kunida, Katsuyuki; Matsuda, Michiyuki; Aoki, Kazuhiro

    2012-05-15

    Cell migration plays an important role in many physiological processes. Rho GTPases (Rac1, Cdc42, RhoA) and phosphatidylinositols have been extensively studied in directional cell migration. However, it remains unclear how Rho GTPases and phosphatidylinositols regulate random cell migration in space and time. We have attempted to address this issue using fluorescence resonance energy transfer (FRET) imaging and statistical signal processing. First, we acquired time-lapse images of random migration of HT-1080 fibrosarcoma cells expressing FRET biosensors of Rho GTPases and phosphatidyl inositols. We developed an image-processing algorithm to extract FRET values and velocities at the leading edge of migrating cells. Auto- and cross-correlation analysis suggested the involvement of feedback regulations among Rac1, phosphatidyl inositols and membrane protrusions. To verify the feedback regulations, we employed an acute inhibition of the signaling pathway with pharmaceutical inhibitors. The inhibition of actin polymerization decreased Rac1 activity, indicating the presence of positive feedback from actin polymerization to Rac1. Furthermore, treatment with PI3-kinase inhibitor induced an adaptation of Rac1 activity, i.e. a transient reduction of Rac1 activity followed by recovery to the basal level. In silico modeling that reproduced the adaptation predicted the existence of a negative feedback loop from Rac1 to actin polymerization. Finally, we identified MLCK as the probable controlling factor in the negative feedback. These findings quantitatively demonstrate positive and negative feedback loops that involve actin, Rac1 and MLCK, and account for the ordered patterns of membrane dynamics observed in randomly migrating cells.

  9. [Use of self-organizing neural networks (Kohonen maps) for classification of voice acoustic signals exemplified by the infant voice with and without time-delayed auditory feedback].

    PubMed

    Schönweiler, R; Kaese, S; Möller, S; Rinscheid, A; Ptok, M

    1996-04-01

    Subjective and auditory assessment of the voice is now more commonly being replaced by objective voice analysis. Because of the amount of data available from computer-aided voice analysis, subjective selection and interpretation of single data sets remain a matter of experience of the individual investigator. Since neuronal networks are widely used in telecommunication and speech recognition, we applied self-organizing Kohonen networks to classify voice patterns. In the phase of "learning," the Kohonen map is adapted to patterns of the primary signals obtained. If, in the phase of using the map, the input signal hits the field of the primary signals, it will resemble them closely. In this study, we recorded newborn and young infant cries using a DAT recorder and a high-quality microphone. The cries were elicited by wearing uncomfortable headphones ("cries of discomfort"). Spectrographic characteristics of the cries were classified by 20-step bark spectra and then applied to the neuronal networks. It was possible to recognize similarities of different cries of the same children and interindividual differences, as well as cries of children with profound hearing loss. In addition, delayed auditory feedback at 80 dB SL was presented to 27 children via headphone using a three-headed tape-recorder as a model for induced individual cry changes. However, it was not possible to classify short-term changes as in a delayed feedback procedure. Nevertheless, neuronal networks may be helpful as an additional tool in spectrographic voice analysis.

  10. CD28 signal transduction pathways. A comparison of B7-1 and B7-2 regulation of the map kinases: ERK2 and Jun kinases.

    PubMed

    Nunes, J A; Battifora, M; Woodgett, J R; Truneh, A; Olive, D; Cantrell, D A

    1996-01-01

    The present study compares the mitogen-activated protein (MAP) kinase responses in T cells activated with the CD28 ligands B7-1 (CD80) and B7-2/B70 (CD86). Ligands B7-1 and B7-2 do not activate the Raf-1/ERK2 cascade, but share the ability to activate related Jun kinases. These natural ligands for CD28 had no stimulatory effect alone on Jun kinase activation, but the data show that B7-1 and B7-2 could both co-operate with intracellular Ca2+ increase and protein kinase C (PKC) activation to stimulate Jun kinases. The present study shows that the interaction of CD28 with its ligands B7-1 and B7-2 can induce identical signal transduction through the MAP kinase cascades.

  11. A first look at the application of signal extraction techniques to the analysis of body surface potential maps

    NASA Technical Reports Server (NTRS)

    Weinstein, S. B.; Mcneel, M. L.; Matthews, E.; Fischmann, E. J.

    1976-01-01

    Partial body surface potential maps from both normal subjects and subjects with independently diagnosed myocardial infarcts are visually compared from superimposed plots. A correlation test is devised to distinguish the two groups, with the reference waveform determined by means of a gradient-search algorithm. The results are encouraging, and suggest further investigation of these techniques as a future diagnostic tool.

  12. Resveratrol suppresses prostaglandin F(2α)-induced osteoprotegerin synthesis in osteoblasts: inhibition of the MAP kinase signaling.

    PubMed

    Kuroyanagi, Gen; Tokuda, Haruhiko; Matsushima-Nishiwaki, Rie; Kondo, Akira; Mizutani, Jun; Kozawa, Osamu; Otsuka, Takanobu

    2014-01-15

    Resveratrol, a natural polyphenol abundantly found in grape skins and red wine, possesses various beneficial properties for human health. In the present study, we investigated the mechanism underlying the effects of prostaglandin F2α (PGF2α) on osteoprotegerin (OPG) synthesis and of resveratrol on the OPG synthesis in osteoblast-like MC3T3-E1 cells. PGF2α stimulated both the release of the OPG protein and the expression of OPG mRNA. Treatment with PD98059, SB203580 and SP600125, specific inhibitors of MEK1/2, p38 mitogen-activated protein (MAP) kinase and stress-activated protein kinase/c-jun N-terminal kinase (SAPK/JNK) all suppressed the OPG release induced by PGF2α. Resveratrol also significantly reduced the PGF2α-stimulated OPG release and the mRNA levels of OPG. Similarly, treatment with SRT1720, an activator of SIRT1, also suppressed the PGF2α-stimulated OPG release. Resveratrol and SRT1720 both attenuated the phosphorylation of p44/p42 MAP kinase, MEK1/2, Raf-1, p38 MAP kinase and SAPK/JNK induced by PGF2α. These findings strongly suggest that resveratrol suppresses PGF2α-stimulated OPG synthesis by inhibiting the MAP kinase pathways in osteoblasts, and that the effect is mediated via SIRT1 activation.

  13. Mapping Van

    NASA Technical Reports Server (NTRS)

    1994-01-01

    A NASA Center for the Commercial Development of Space (CCDS) - developed system for satellite mapping has been commercialized for the first time. Global Visions, Inc. maps an area while driving along a road in a sophisticated mapping van equipped with satellite signal receivers, video cameras and computer systems for collecting and storing mapping data. Data is fed into a computerized geographic information system (GIS). The resulting amps can be used for tax assessment purposes, emergency dispatch vehicles and fleet delivery companies as well as other applications.

  14. Analysis of signal transduction pathways during anoxia exposure in a marine snail: a role for p38 MAP kinase and downstream signaling cascades.

    PubMed

    Larade, Kevin; Storey, Kenneth B

    2006-01-01

    The responses of members of the three main MAPK families (ERK, JNK/SAPK, p38 MAPK), as well as selected peripheral pathways, were examined in hepatopancreas of the marine periwinkle, Littorina littorea, to determine if anoxia exposure influenced the total protein content or the phosphorylation status of any key components. The content of active phospho-p38 MAPK was 2-fold higher in hepatopancreas from anoxic snails relative to controls. A 1.7-fold increase in the amount of phospho-Hsp27 and a 1.3-fold increase in phospho-CREB correlated well with the changes in p38 MAPK phosphorylation. Activation of these factors via p38 MAPK may be vital to the reorganization of metabolic responses to anoxia in hepatopancreas. No changes in components of the JNK/SAPK and ERK pathways occurred and transcription factors involved in lipid metabolism did not appear to be affected by anoxia. The present analysis of a variety of signaling pathways has implicated the p38 MAPK pathway as a key anoxia-responsive signal transduction pathway in L. littorea. PMID:16326124

  15. Endocytosis separates EGF receptors from endogenous fluorescently labeled HRas and diminishes receptor signaling to MAP kinases in endosomes.

    PubMed

    Pinilla-Macua, Itziar; Watkins, Simon C; Sorkin, Alexander

    2016-02-23

    Signaling from epidermal growth factor receptor (EGFR) to extracellular-stimuli-regulated protein kinase 1/2 (ERK1/2) is proposed to be transduced not only from the cell surface but also from endosomes, although the role of endocytosis in this signaling pathway is controversial. Ras is the only membrane-anchored component in the EGFR-ERK signaling axis, and therefore, its location determines intracellular sites of downstream signaling. Hence, we labeled endogenous H-Ras (HRas) with mVenus fluorescent protein using gene editing in HeLa cells. mVenus-HRas was primarily located at the plasma membrane, and in small amounts in tubular recycling endosomes and associated vesicles. EGF stimulation resulted in fast but transient activation of mVenus-HRas. Although EGF:EGFR complexes were rapidly accumulated in endosomes together with the Grb2 adaptor, very little, if any, mVenus-HRas was detected in these endosomes. Interestingly, the activities of MEK1/2 and ERK1/2 remained high beyond the point of the physical separation of HRas from EGF:EGFR complexes and down-regulation of Ras activity. Paradoxically, this sustained MEK1/2 and ERK1/2 activation was dependent on the active EGFR kinase. Cell surface biotinylation and selective inactivation of surface EGFRs suggested that a small fraction of active EGFRs remaining in the plasma membrane is responsible for continuous signaling to MEK1/2 and ERK1/2. We propose that, under physiological conditions of cell stimulation, EGFR endocytosis serves to spatially separate EGFR-Grb2 complexes and Ras, thus terminating Ras-mediated signaling. However, sustained minimal activation of Ras by a small pool of active EGFRs in the plasma membrane is sufficient for extending MEK1/2 and ERK1/2 activities.

  16. Endocytosis separates EGF receptors from endogenous fluorescently labeled HRas and diminishes receptor signaling to MAP kinases in endosomes

    PubMed Central

    Pinilla-Macua, Itziar; Watkins, Simon C.; Sorkin, Alexander

    2016-01-01

    Signaling from epidermal growth factor receptor (EGFR) to extracellular-stimuli–regulated protein kinase 1/2 (ERK1/2) is proposed to be transduced not only from the cell surface but also from endosomes, although the role of endocytosis in this signaling pathway is controversial. Ras is the only membrane-anchored component in the EGFR–ERK signaling axis, and therefore, its location determines intracellular sites of downstream signaling. Hence, we labeled endogenous H-Ras (HRas) with mVenus fluorescent protein using gene editing in HeLa cells. mVenus-HRas was primarily located at the plasma membrane, and in small amounts in tubular recycling endosomes and associated vesicles. EGF stimulation resulted in fast but transient activation of mVenus-HRas. Although EGF:EGFR complexes were rapidly accumulated in endosomes together with the Grb2 adaptor, very little, if any, mVenus-HRas was detected in these endosomes. Interestingly, the activities of MEK1/2 and ERK1/2 remained high beyond the point of the physical separation of HRas from EGF:EGFR complexes and down-regulation of Ras activity. Paradoxically, this sustained MEK1/2 and ERK1/2 activation was dependent on the active EGFR kinase. Cell surface biotinylation and selective inactivation of surface EGFRs suggested that a small fraction of active EGFRs remaining in the plasma membrane is responsible for continuous signaling to MEK1/2 and ERK1/2. We propose that, under physiological conditions of cell stimulation, EGFR endocytosis serves to spatially separate EGFR–Grb2 complexes and Ras, thus terminating Ras-mediated signaling. However, sustained minimal activation of Ras by a small pool of active EGFRs in the plasma membrane is sufficient for extending MEK1/2 and ERK1/2 activities. PMID:26858456

  17. Stimulation of PPC Affects the Mapping between Motion and Force Signals for Stiffness Perception But Not Motion Control

    PubMed Central

    Mawase, Firas; Karniel, Amir; Donchin, Opher; Rothwell, John; Nisky, Ilana; Davare, Marco

    2016-01-01

    How motion and sensory inputs are combined to assess an object's stiffness is still unknown. Here, we provide evidence for the existence of a stiffness estimator in the human posterior parietal cortex (PPC). We showed previously that delaying force feedback with respect to motion when interacting with an object caused participants to underestimate its stiffness. We found that applying theta-burst transcranial magnetic stimulation (TMS) over the PPC, but not the dorsal premotor cortex, enhances this effect without affecting movement control. We explain this enhancement as an additional lag in force signals. This is the first causal evidence that the PPC is not only involved in motion control, but also has an important role in perception that is disassociated from action. We provide a computational model suggesting that the PPC integrates position and force signals for perception of stiffness and that TMS alters the synchronization between the two signals causing lasting consequences on perceptual behavior. SIGNIFICANCE STATEMENT When selecting an object such as a ripe fruit or sofa, we need to assess the object's stiffness. Because we lack dedicated stiffness sensors, we rely on an as yet unknown mechanism that generates stiffness percepts by combining position and force signals. Here, we found that the posterior parietal cortex (PPC) contributes to combining position and force signals for stiffness estimation. This finding challenges the classical view about the role of the PPC in regulating position signals only for motion control because we highlight a key role of the PPC in perception that is disassociated from action. Altogether this sheds light on brain mechanisms underlying the interaction between action and perception and may help in the development of better teleoperation systems and rehabilitation of patients with sensory impairments. PMID:27733607

  18. Nitric Oxide Affects ERK Signaling through Down-Regulation of MAP Kinase Phosphatase Levels during Larval Development of the Ascidian Ciona intestinalis

    PubMed Central

    Palumbo, Anna

    2014-01-01

    In the ascidian Ciona intestinalis larval development and metamorphosis require a complex interplay of events, including nitric oxide (NO) production, MAP kinases (ERK, JNK) and caspase-3 activation. We have previously shown that NO levels affect the rate of metamorphosis, regulate caspase activity and promote an oxidative stress pathway, resulting in protein nitration. Here, we report that NO down-regulates MAP kinase phosphatases (mkps) expression affecting positively ERK signaling. By pharmacological approach, we observed that the reduction of endogenous NO levels caused a decrease of ERK phosphorylation, whereas increasing levels of NO induced ERK activation. We have also identified the ERK gene network affected by NO, including mpk1, mpk3 and some key developmental genes by quantitative gene expression analysis. We demonstrate that NO induces an ERK-independent down-regulation of mkp1 and mkp3, responsible for maintaining the ERK phosphorylation levels necessary for transcription of key metamorphic genes, such as the hormone receptor rev-erb and the van willebrand protein vwa1c. These results add new insights into the role played by NO during larval development and metamorphosis in Ciona, highlighting the cross-talk between different signaling pathways. PMID:25058405

  19. Mapping physiological G protein-coupled receptor signaling pathways reveals a role for receptor phosphorylation in airway contraction

    PubMed Central

    Bradley, Sophie J.; Iglesias, Max Maza; Kong, Kok Choi; Butcher, Adrian J.; Plouffe, Bianca; Goupil, Eugénie; Bourgognon, Julie-Myrtille; Macedo-Hatch, Timothy; LeGouill, Christian; Russell, Kirsty; Laporte, Stéphane A.; König, Gabriele M.; Kostenis, Evi; Bouvier, Michel; Chung, Kian Fan; Amrani, Yassine; Tobin, Andrew B.

    2016-01-01

    G protein-coupled receptors (GPCRs) are known to initiate a plethora of signaling pathways in vitro. However, it is unclear which of these pathways are engaged to mediate physiological responses. Here, we examine the distinct roles of Gq/11-dependent signaling and receptor phosphorylation-dependent signaling in bronchial airway contraction and lung function regulated through the M3-muscarinic acetylcholine receptor (M3-mAChR). By using a genetically engineered mouse expressing a G protein-biased M3-mAChR mutant, we reveal the first evidence, to our knowledge, of a role for M3-mAChR phosphorylation in bronchial smooth muscle contraction in health and in a disease state with relevance to human asthma. Furthermore, this mouse model can be used to distinguish the physiological responses that are regulated by M3-mAChR phosphorylation (which include control of lung function) from those responses that are downstream of G protein signaling. In this way, we present an approach by which to predict the physiological/therapeutic outcome of M3-mAChR–biased ligands with important implications for drug discovery. PMID:27071102

  20. N-cadherin mediated distribution of beta-catenin alters MAP kinase and BMP-2 signaling on chondrogenesis-related gene expression.

    PubMed

    Modarresi, Rozbeh; Lafond, Toulouse; Roman-Blas, Jorge A; Danielson, Keith G; Tuan, Rocky S; Seghatoleslami, M Reza

    2005-05-01

    We have examined the effect of calcium-dependent adhesion, mediated by N-cadherin, on cell signaling during chondrogenesis of multipotential embryonic mouse C3H10T1/2 cells. The activity of chondrogenic genes, type II collagen, aggrecan, and Sox9 were examined in monolayer (non-chondrogenic), and micromass (chondrogenic) cultures of parental C3H10T1/2 cells and altered C3H10T1/2 cell lines that express a dominant negative form of N-cadherin (delta390-T1/2) or overexpress normal N-cadherin (MNCD2-T1/2). Our findings show that missexpression or inhibition of N-cadherin in C3H10T1/2 cells results in temporal and spatial changes in expression of the chondrogenic genes Sox9, aggrecan, and collagen type II. We have also analyzed activity of the serum response factor (SRF), a nuclear target of MAP kinase signaling implicated in chondrogenesis. In semi-confluent monolayer cultures (minimum cell-cell contact) of C3H10T1/2, MNCD2-T1/2, or delta390-T1/2 cells, there was no significant change in the pattern of MAP kinase or bone morphogenetic protein-2 (BMP-2) regulation of SRF. However, in micromass cultures, the effect of MAP kinase and BMP-2 on SRF activity was proportional to the nuclear localization of beta-catenin, a Wnt stabilized cytoplasmic factor that can associate with lymphoid enhancer-binding factor (LEF) to serve as a transcription factor. Our findings suggest that the extent of adherens junction formation mediated by N-cadherin can modulate the potential Wnt-induced nuclear activity of beta-catenin. PMID:15723280

  1. Human β-Cell Proliferation and Intracellular Signaling Part 2: Still Driving in the Dark Without a Road Map

    PubMed Central

    Bernal-Mizrachi, Ernesto; Kulkarni, Rohit N.; Scott, Donald K.; Mauvais-Jarvis, Franck; Stewart, Andrew F.; Garcia-Ocaña, Adolfo

    2014-01-01

    Enhancing β-cell proliferation is a major goal for type 1 and type 2 diabetes research. Unraveling the network of β-cell intracellular signaling pathways that promote β-cell replication can provide the tools to address this important task. In a previous Perspectives in Diabetes article, we discussed what was known regarding several important intracellular signaling pathways in rodent β-cells, including the insulin receptor substrate/phosphatidylinositol-3 kinase/Akt (IRS-PI3K-Akt) pathways, glycogen synthase kinase-3 (GSK3) and mammalian target of rapamycin (mTOR) S6 kinase pathways, protein kinase Cζ (PKCζ) pathways, and their downstream cell-cycle molecular targets, and contrasted that ample knowledge to the small amount of complementary data on human β-cell intracellular signaling pathways. In this Perspectives, we summarize additional important information on signaling pathways activated by nutrients, such as glucose; growth factors, such as epidermal growth factor, platelet-derived growth factor, and Wnt; and hormones, such as leptin, estrogen, and progesterone, that are linked to rodent and human β-cell proliferation. With these two Perspectives, we attempt to construct a brief summary of knowledge for β-cell researchers on mitogenic signaling pathways and to emphasize how little is known regarding intracellular events linked to human β-cell replication. This is a critical aspect in the long-term goal of expanding human β-cells for the prevention and/or cure of type 1 and type 2 diabetes. PMID:24556859

  2. Aloe-Emodin Induces Chondrogenic Differentiation of ATDC5 Cells via MAP Kinases and BMP-2 Signaling Pathways.

    PubMed

    Yang, Ming; Li, Liang; Heo, Seok-Mo; Soh, Yunjo

    2016-07-01

    Endochondral bone formation is the process by which mesenchymal cells condense into chondrocytes, which are ultimately responsible for new bone formation. The processes of chondrogenic differentiation and hypertrophy are critical for bone formation and are therefore highly regulated. The present study was designed to investigate the effect of aloe-emodin on chondrogenic differentiation in clonal mouse chondrogenic ATDC5 cells. Aloe-emodin treatment stimulated the accumulation of cartilage nodules in a dose-dependent manner. ATDC5 cells were treated with aloe-emodin and stained with alcian blue. Compared with the control cells, the ATDC5 cells showed more intense alcian blue staining. This finding suggested that aloe-emodin induced the synthesis of matrix proteoglycans and increased the activity of alkaline phosphatase. Aloe-emodin also enhanced the expressions of chondrogenic marker genes such as collagen II, collagen X, BSP and RunX2 in a time-dependent manner. Furthermore, examination of the MAPK signaling pathway showed that aloe-emodin increased the activation of extracellular signal-regulated kinase (ERK), but had no effect on p38 and c-jun N-terminal kinase (JNK). Aloe-emodin also enhanced the protein expression of BMP-2 in a time-dependent manner. Thus, these results showed that aloe-emodin exhibited chodromodulating effects via the BMP-2 or ERK signaling pathway. Aloe-emodin may have potential future applications for the treatment of growth disorders. PMID:27350340

  3. The Ste5 scaffold directs mating signaling by catalytically unlocking the Fus3 MAP kinase for activation.

    PubMed

    Good, Matthew; Tang, Grace; Singleton, Julie; Reményi, Attila; Lim, Wendell A

    2009-03-20

    The scaffold protein Ste5 is required to properly direct signaling through the yeast mating pathway to the mitogen-activated protein kinase (MAPK), Fus3. Scaffolds are thought to function by tethering kinase and substrate in proximity. We find, however, that the previously identified Fus3-binding site on Ste5 is not required for signaling, suggesting an alternative mechanism controls Fus3's activation by the MAPKK Ste7. Reconstituting MAPK signaling in vitro, we find that Fus3 is an intrinsically poor substrate for Ste7, although the related filamentation MAPK, Kss1, is an excellent substrate. We identify and structurally characterize a domain in Ste5 that catalytically unlocks Fus3 for phosphorylation by Ste7. This domain selectively increases the k(cat) of Ste7-->Fus3 phosphorylation but has no effect on Ste7-->Kss1 phosphorylation. The dual requirement for both Ste7 and this Ste5 domain in Fus3 activation explains why Fus3 is selectively activated by the mating pathway and not by other pathways that also utilize Ste7. PMID:19303851

  4. Aloe-Emodin Induces Chondrogenic Differentiation of ATDC5 Cells via MAP Kinases and BMP-2 Signaling Pathways

    PubMed Central

    Yang, Ming; Li, Liang; Heo, Seok-Mo; Soh, Yunjo

    2016-01-01

    Endochondral bone formation is the process by which mesenchymal cells condense into chondrocytes, which are ultimately responsible for new bone formation. The processes of chondrogenic differentiation and hypertrophy are critical for bone formation and are therefore highly regulated. The present study was designed to investigate the effect of aloe-emodin on chondrogenic differentiation in clonal mouse chondrogenic ATDC5 cells. Aloe-emodin treatment stimulated the accumulation of cartilage nodules in a dose-dependent manner. ATDC5 cells were treated with aloe-emodin and stained with alcian blue. Compared with the control cells, the ATDC5 cells showed more intense alcian blue staining. This finding suggested that aloe-emodin induced the synthesis of matrix proteoglycans and increased the activity of alkaline phosphatase. Aloe-emodin also enhanced the expressions of chondrogenic marker genes such as collagen II, collagen X, BSP and RunX2 in a time-dependent manner. Furthermore, examination of the MAPK signaling pathway showed that aloe-emodin increased the activation of extracellular signal-regulated kinase (ERK), but had no effect on p38 and c-jun N-terminal kinase (JNK). Aloe-emodin also enhanced the protein expression of BMP-2 in a time-dependent manner. Thus, these results showed that aloe-emodin exhibited chodromodulating effects via the BMP-2 or ERK signaling pathway. Aloe-emodin may have potential future applications for the treatment of growth disorders. PMID:27350340

  5. Stable Pseudohyphal Growth in Budding Yeast Induced by Synergism between Septin Defects and Altered MAP-kinase Signaling.

    PubMed

    Kim, Junwon; Rose, Mark D

    2015-12-01

    Upon nutrient limitation, budding yeasts like Saccharomyces cerevisiae can be induced to adopt alternate filament-like growth patterns called diploid pseudohyphal or invasive haploid growth. Here, we report a novel constitutive pseudohyphal growth state, sharing some characteristics with classic forms of filamentous growth, but differing in crucial aspects of morphology, growth conditions and genetic regulation. The constitutive pseudohyphal state is observed in fus3 mutants containing various septin assembly defects, which we refer to as sadF growth (septin assembly defect induced filamentation) to distinguish it from classic filamentation pathways. Similar to other filamentous states, sadF cultures comprise aggregated chains of highly elongated cells. Unlike the classic pathways, sadF growth occurs in liquid rich media, requiring neither starvation nor the key pseudohyphal proteins, Flo8p and Flo11p. Moreover sadF growth occurs in haploid strains of S288C genetic background, which normally cannot undergo pseudohyphal growth. The sadF cells undergo highly polarized bud growth during prolonged G2 delays dependent on Swe1p. They contain septin structures distinct from classical pseudo-hyphae and FM4-64 labeling at actively growing tips similar to the Spitzenkörper observed in true hyphal growth. The sadF growth state is induced by synergism between Kss1p-dependent signaling and septin assembly defects; mild disruption of mitotic septins activates Kss1p-dependent gene expression, which exacerbates the septin defects, leading to hyper-activation of Kss1p. Unlike classical pseudo-hyphal growth, sadF signaling requires Ste5, Ste4 and Ste18, the scaffold protein and G-protein β and γ subunits from the pheromone response pathway, respectively. A swe1 mutation largely abolished signaling, breaking the positive feedback that leads to amplification of sadF signaling. Taken together, our findings show that budding yeast can access a stable constitutive pseudohyphal growth

  6. Stable Pseudohyphal Growth in Budding Yeast Induced by Synergism between Septin Defects and Altered MAP-kinase Signaling

    PubMed Central

    Kim, Junwon; Rose, Mark D.

    2015-01-01

    Upon nutrient limitation, budding yeasts like Saccharomyces cerevisiae can be induced to adopt alternate filament-like growth patterns called diploid pseudohyphal or invasive haploid growth. Here, we report a novel constitutive pseudohyphal growth state, sharing some characteristics with classic forms of filamentous growth, but differing in crucial aspects of morphology, growth conditions and genetic regulation. The constitutive pseudohyphal state is observed in fus3 mutants containing various septin assembly defects, which we refer to as sadF growth (septin assembly defect induced filamentation) to distinguish it from classic filamentation pathways. Similar to other filamentous states, sadF cultures comprise aggregated chains of highly elongated cells. Unlike the classic pathways, sadF growth occurs in liquid rich media, requiring neither starvation nor the key pseudohyphal proteins, Flo8p and Flo11p. Moreover sadF growth occurs in haploid strains of S288C genetic background, which normally cannot undergo pseudohyphal growth. The sadF cells undergo highly polarized bud growth during prolonged G2 delays dependent on Swe1p. They contain septin structures distinct from classical pseudo-hyphae and FM4-64 labeling at actively growing tips similar to the Spitzenkörper observed in true hyphal growth. The sadF growth state is induced by synergism between Kss1p-dependent signaling and septin assembly defects; mild disruption of mitotic septins activates Kss1p-dependent gene expression, which exacerbates the septin defects, leading to hyper-activation of Kss1p. Unlike classical pseudo-hyphal growth, sadF signaling requires Ste5, Ste4 and Ste18, the scaffold protein and G-protein β and γ subunits from the pheromone response pathway, respectively. A swe1 mutation largely abolished signaling, breaking the positive feedback that leads to amplification of sadF signaling. Taken together, our findings show that budding yeast can access a stable constitutive pseudohyphal growth

  7. Archaeological applications of laser-induced breakdown spectroscopy: an example from the Coso Volcanic Field, California, using advanced statistical signal processing analysis

    SciTech Connect

    Remus, Jeremiah J.; Gottfried, Jennifer L.; Harmon, Russell S.; Draucker, Anne; Baron, Dirk; Yohe, Robert

    2010-05-01

    of the classifier setup considered in this study include the training/testing routine (a 27-fold leave-one-sample-out setup versus a simple split of the data into separate sets for training and evaluation), the number of latent variables used in the regression model, and whether PLSDA operating on the entire broadband LIBS spectrum is superior to that using only a selected subset of LIBS emission lines. The results point to the robustness of the PLSDA technique and suggest that LIBS analysis combined with the appropriate statistical signal processing has the potential to be a useful tool for chemical analysis of archaeological artifacts and geological specimens.

  8. Integrating Map Algebra and Statistical Modeling for Spatio-Temporal Analysis of Monthly Mean Daily Incident Photosynthetically Active Radiation (PAR) over a Complex Terrain

    PubMed Central

    Evrendilek, Fatih

    2007-01-01

    This study aims at quantifying spatio-temporal dynamics of monthly mean daily incident photosynthetically active radiation (PAR) over a vast and complex terrain such as Turkey. The spatial interpolation method of universal kriging, and the combination of multiple linear regression (MLR) models and map algebra techniques were implemented to generate surface maps of PAR with a grid resolution of 500 × 500 m as a function of five geographical and 14 climatic variables. Performance of the geostatistical and MLR models was compared using mean prediction error (MPE), root-mean-square prediction error (RMSPE), average standard prediction error (ASE), mean standardized prediction error (MSPE), root-mean-square standardized prediction error (RMSSPE), and adjusted coefficient of determination (R2adj.). The best-fit MLR- and universal kriging-generated models of monthly mean daily PAR were validated against an independent 37-year observed dataset of 35 climate stations derived from 160 stations across Turkey by the Jackknifing method. The spatial variability patterns of monthly mean daily incident PAR were more accurately reflected in the surface maps created by the MLR-based models than in those created by the universal kriging method, in particular, for spring (May) and autumn (November). The MLR-based spatial interpolation algorithms of PAR described in this study indicated the significance of the multifactor approach to understanding and mapping spatio-temporal dynamics of PAR for a complex terrain over meso-scales.

  9. STATISTICAL ANALYSIS OF THE HEAVY NEUTRAL ATOMS MEASURED BY IBEX

    SciTech Connect

    Park, Jeewoo; Kucharek, Harald; Möbius, Eberhard; Galli, André; Livadiotis, George; Fuselier, Steve A.; McComas, David J.

    2015-10-15

    We investigate the directional distribution of heavy neutral atoms in the heliosphere by using heavy neutral maps generated with the IBEX-Lo instrument over three years from 2009 to 2011. The interstellar neutral (ISN) O and Ne gas flow was found in the first-year heavy neutral map at 601 keV and its flow direction and temperature were studied. However, due to the low counting statistics, researchers have not treated the full sky maps in detail. The main goal of this study is to evaluate the statistical significance of each pixel in the heavy neutral maps to get a better understanding of the directional distribution of heavy neutral atoms in the heliosphere. Here, we examine three statistical analysis methods: the signal-to-noise filter, the confidence limit method, and the cluster analysis method. These methods allow us to exclude background from areas where the heavy neutral signal is statistically significant. These methods also allow the consistent detection of heavy neutral atom structures. The main emission feature expands toward lower longitude and higher latitude from the observational peak of the ISN O and Ne gas flow. We call this emission the extended tail. It may be an imprint of the secondary oxygen atoms generated by charge exchange between ISN hydrogen atoms and oxygen ions in the outer heliosheath.

  10. Density Equalizing Map Projections

    1995-07-01

    A geographic map is mathematically transformed so that the subareas of the map are proportional to a given quantity such as population. In other words, population density is equalized over the entire map. The transformed map can be used as a display tool, or it can be statistically analyzed. For example, cases of disease plotted on the transformed map should be uniformly distributed at random, if disease rates are everywhere equal. Geographic clusters of diseasemore » can be readily identified, and their statistical significance determined, on a density equalized map.« less

  11. Cyanidin-3-glucoside inhibits UVB-induced oxidative damage and inflammation by regulating MAP kinase and NF-κB signaling pathways in SKH-1 hairless mice skin

    SciTech Connect

    Pratheeshkumar, Poyil; Son, Young-Ok; Wang, Xin; Divya, Sasidharan Padmaja; Joseph, Binoy; Hitron, John Andrew; Wang, Lei; Kim, Donghern; Yin, Yuanqin; Roy, Ram Vinod; Lu, Jian; Zhang, Zhuo; Wang, Yitao; and others

    2014-10-01

    Skin cancer is one of the most commonly diagnosed cancers in the United States. Exposure to ultraviolet-B (UVB) radiation induces inflammation and photocarcinogenesis in mammalian skin. Cyanidin-3-glucoside (C3G), a member of the anthocyanin family, is present in various vegetables and fruits especially in edible berries, and displays potent antioxidant and anticarcinogenic properties. In this study, we have assessed the in vivo effects of C3G on UVB irradiation induced chronic inflammatory responses in SKH-1 hairless mice, a well-established model for UVB-induced skin carcinogenesis. Here, we show that C3G inhibited UVB-induced skin damage and inflammation in SKH-1 hairless mice. Our results indicate that C3G inhibited glutathione depletion, lipid peroxidation and myeloperoxidation in mouse skin by chronic UVB exposure. C3G significantly decreased the production of UVB-induced pro-inflammatory cytokines, such as IL-6 and TNF-α, associated with cutaneous inflammation. Likewise, UVB-induced inflammatory responses were diminished by C3G as observed by a remarkable reduction in the levels of phosphorylated MAP kinases, Erk1/2, p38, JNK1/2 and MKK4. Furthermore, C3G also decreased UVB-induced cyclooxygenase-2 (COX-2), PGE{sub 2} and iNOS levels, which are well-known key mediators of inflammation and cancer. Treatment with C3G inhibited UVB-induced nuclear translocation of NF-κB and degradation of IκBα in mice skin. Immunofluorescence assay revealed that topical application of C3G inhibited the expression of 8-hydroxy-2′-deoxyguanosine, proliferating cell nuclear antigen, and cyclin D1 in chronic UVB exposed mouse skin. Collectively, these data indicates that C3G can provide substantial protection against the adverse effects of UVB radiation by modulating UVB-induced MAP kinase and NF-κB signaling pathways. - Highlights: • C3G inhibited UVB-induced oxidative damage and inflammation. • C3G inhibited UVB-induced COX-2, iNOS and PGE{sub 2} production. • C3G

  12. Statistical design for microwave systems

    NASA Technical Reports Server (NTRS)

    Cooke, Roland; Purviance, John

    1991-01-01

    This paper presents an introduction to statistical system design. Basic ideas needed to understand statistical design and a method for implementing statistical design are presented. The nonlinear characteristics of the system amplifiers and mixers are accounted for in the given examples. The specification of group delay, signal-to-noise ratio and output power are considered in these statistical designs.

  13. DLK-1/p38 MAP Kinase Signaling Controls Cilium Length by Regulating RAB-5 Mediated Endocytosis in Caenorhabditis elegans.

    PubMed

    van der Vaart, Aniek; Rademakers, Suzanne; Jansen, Gert

    2015-12-01

    Cilia are sensory organelles present on almost all vertebrate cells. Cilium length is constant, but varies between cell types, indicating that cilium length is regulated. How this is achieved is unclear, but protein transport in cilia (intraflagellar transport, IFT) plays an important role. Several studies indicate that cilium length and function can be modulated by environmental cues. As a model, we study a C. elegans mutant that carries a dominant active G protein α subunit (gpa-3QL), resulting in altered IFT and short cilia. In a screen for suppressors of the gpa-3QL short cilium phenotype, we identified uev-3, which encodes an E2 ubiquitin-conjugating enzyme variant that acts in a MAP kinase pathway. Mutation of two other components of this pathway, dual leucine zipper-bearing MAPKKK DLK-1 and p38 MAPK PMK-3, also suppress the gpa-3QL short cilium phenotype. However, this suppression seems not to be caused by changes in IFT. The DLK-1/p38 pathway regulates several processes, including microtubule stability and endocytosis. We found that reducing endocytosis by mutating rabx-5 or rme-6, RAB-5 GEFs, or the clathrin heavy chain, suppresses gpa-3QL. In addition, gpa-3QL animals showed reduced levels of two GFP-tagged proteins involved in endocytosis, RAB-5 and DPY-23, whereas pmk-3 mutant animals showed accumulation of GFP-tagged RAB-5. Together our results reveal a new role for the DLK-1/p38 MAPK pathway in control of cilium length by regulating RAB-5 mediated endocytosis.

  14. DLK-1/p38 MAP Kinase Signaling Controls Cilium Length by Regulating RAB-5 Mediated Endocytosis in Caenorhabditis elegans

    PubMed Central

    van der Vaart, Aniek; Rademakers, Suzanne; Jansen, Gert

    2015-01-01

    Cilia are sensory organelles present on almost all vertebrate cells. Cilium length is constant, but varies between cell types, indicating that cilium length is regulated. How this is achieved is unclear, but protein transport in cilia (intraflagellar transport, IFT) plays an important role. Several studies indicate that cilium length and function can be modulated by environmental cues. As a model, we study a C. elegans mutant that carries a dominant active G protein α subunit (gpa-3QL), resulting in altered IFT and short cilia. In a screen for suppressors of the gpa-3QL short cilium phenotype, we identified uev-3, which encodes an E2 ubiquitin-conjugating enzyme variant that acts in a MAP kinase pathway. Mutation of two other components of this pathway, dual leucine zipper-bearing MAPKKK DLK-1 and p38 MAPK PMK-3, also suppress the gpa-3QL short cilium phenotype. However, this suppression seems not to be caused by changes in IFT. The DLK-1/p38 pathway regulates several processes, including microtubule stability and endocytosis. We found that reducing endocytosis by mutating rabx-5 or rme-6, RAB-5 GEFs, or the clathrin heavy chain, suppresses gpa-3QL. In addition, gpa-3QL animals showed reduced levels of two GFP-tagged proteins involved in endocytosis, RAB-5 and DPY-23, whereas pmk-3 mutant animals showed accumulation of GFP-tagged RAB-5. Together our results reveal a new role for the DLK-1/p38 MAPK pathway in control of cilium length by regulating RAB-5 mediated endocytosis. PMID:26657059

  15. The MAPKKKs Ste11 and Bck1 jointly transduce the high oxidative stress signal through the cell wall integrity MAP kinase pathway

    PubMed Central

    Jin, Chunyan; Kim, Stephen K.; Willis, Stephen D.; Cooper, Katrina F.

    2016-01-01

    Oxidative stress stimulates the Rho1 GTPase, which in turn induces the cell wall integrity (CWI) MAP kinase cascade. CWI activation promotes stress-responsive gene expression through activation of transcription factors (Rlm1, SBF) and nuclear release and subsequent destruction of the repressor cyclin C. This study reports that, in response to high hydrogen peroxide exposure, or in the presence of constitutively active Rho1, cyclin C still translocates to the cytoplasm and is degraded in cells lacking Bck1, the MAPKKK of the CWI pathway. However, in mutants defective for both Bck1 and Ste11, the MAPKKK from the high osmolarity, pseudohyphal and mating MAPK pathways, cyclin C nuclear to cytoplasmic relocalization and destruction is prevented. Further analysis revealed that cyclin C goes from a diffuse nuclear signal to a terminal nucleolar localization in this double mutant. Live cell imaging confirmed that cyclin C transiently passes through the nucleolus prior to cytoplasmic entry in wild-type cells. Taken together with previous studies, these results indicate that under low levels of oxidative stress, Bck1 activation is sufficient to induce cyclin C translocation and degradation. However, higher stress conditions also stimulate Ste11, which reinforces the stress signal to cyclin C and other transcription factors. This model would provide a mechanism by which different stress levels can be sensed and interpreted by the cell. PMID:27135035

  16. Hydrogen Peroxide–Mediated Activation of MAP Kinase 6 Modulates Nitric Oxide Biosynthesis and Signal Transduction in Arabidopsis[w

    PubMed Central

    Wang, Pengcheng; Du, Yanyan; Li, Yuan; Ren, Dongtao; Song, Chun-Peng

    2010-01-01

    Nitric oxide (NO) is a bioactive molecule that functions in numerous physiological and developmental processes in plants, including lateral root development. In this study, we used biochemical and genetic approaches to analyze the function of Arabidopsis thaliana mitogen-activated protein kinase 6 (MPK6) in the regulation of NO synthesis in response to hydrogen peroxide (H2O2) during lateral root development. In both mpk6 mutants studied, H2O2-induced NO synthesis and nitrate reductase (NR) activity were decreased dramatically. Furthermore, one NR isoform, NIA2, was required for the MPK6-mediated production of NO induced by H2O2. Notably, NIA2 interacted physically with MPK6 in vitro and in vivo and also served as a substrate of MPK6. Phosphorylation of NIA2 by MPK6 led to an increase in NR activity, and Ser-627 was identified as the putative phosphorylation site on NIA2. Phenotypical analysis revealed that mpk6-2 and mpk6-3 seedlings produce more and longer lateral roots than wild-type plants did after application of the NO donor sodium nitroprusside or H2O2. These data support strongly a function of MPK6 in modulating NO production and signal transduction in response to H2O2 during Arabidopsis root development. PMID:20870959

  17. Nuclear Localization Signal and p53 Binding Site in MAP/ERK Kinase Kinase 1 (MEKK1).

    PubMed

    Chipps, Elizabeth; Protzman, April; Muhi, M Zubayed; Ando, Shoko; Calvet, James P; Islam, M Rafiq

    2015-12-01

    Previously, we showed that Mekk1 translocates to the nucleus, interacts with tumor suppressor protein p53, and co-represses PKD1 transcription via an atypical p53 binding site on the minimal PKD1 promoter (JBC 285:38,818-38,831, 2010). In this study, we report the mechanisms of Mekk1 nuclear transport and p53 binding. Using GFP-linked constitutively active-Mekk1 (CA-Mekk1) and a deletion strategy, we identified a nuclear localization signal (HRDVK) located at amino acid (aa) residues 1,349-1,353 in the C-terminal Mekk1 catalytic domain. Deletion of this sequence in CA-Mekk1 and full-length Mekk1 significantly reduced their nuclear translocation in both HEK293T and COS-1 cells. Using co-immunoprecipitation, we identified an adjacent sequence (GANLID, aa 1,354-1,360) in Mekk1 responsible for p53 binding. Deletion of this sequence markedly reduced the interaction of Mekk1 with p53. Mekk1 does not appear to affect phosphorylation of Ser15, located in the Mdm2 interaction site, or other Ser residues in p53. However, Mekk1 mediates p53 protein stability in the presence of Mdm2 and reduces p53 ubiquitination, suggesting an interference with Mdm2-mediated degradation of p53 by the ubiquitin-proteasome pathway.

  18. Haemophilus parasuis induces activation of NF-κB and MAP kinase signaling pathways mediated by toll-like receptors.

    PubMed

    Chen, Yushan; Liu, Ting; Langford, Paul; Hua, Kexin; Zhou, Shanshan; Zhai, Yajun; Xiao, Hongde; Luo, Rui; Bi, Dingren; Jin, Hui; Zhou, Rui

    2015-06-01

    Glässer's disease in pigs caused by Haemophilus parasuis is characterized by a severe membrane inflammation. In our previous study, we have identified activation of the transcription factor NF-κB after H. parasuis infection of porcine epithelial cells. In this study, we found that H. parasuis infection also contributed to the activation of p38/JNK MAPK pathway predominantly linked to inflammation, but not the ERK MAPK pathway associated with growth, differentiation and development. Inhibition of NF-κB, p38 and JNK but not ERK activity significantly reduced IL-8 and CCL4 expression by H. parasuis. We also found TLR1, TLR2, TLR4 and TLR6 were required for NF-κB, p38 and JNK MAPK activation. Furthermore, MyD88 and TRIF signaling cascades were essential for H. parasuis-induced NF-κB activation. These results provided new insights into the molecular pathways underlying the inflammatory response induced by H. parasuis.

  19. Sevoflurane Stimulates MAP Kinase Signal transduction through the Activation of PKC α and βII in Fetal Rat Cerebral Cortex Cultured Neuron

    PubMed Central

    Hasegawa, Jun; Takekoshi, Susumu; Nagata, Hidetaka; Osamura, R. Yoshiyuki; Suzuki, Toshiyasu

    2006-01-01

    Protein kinase C (PKC) is a key enzyme that participates in various neuronal functions. PKC has also been identified as a target molecule for general anesthetic actions. Raf, mitogen-activated protein kinase (MEK) and extracellular signal-regulated kinase (ERK1/2) have been thought to be target effectors of PKC. In the present study, we attempted to evaluate the effect of sevoflurane on PKC/MAPK cascade signaling in cultured fetal rat cerebral ­cortex neurons, prepared from embryonic day 18 fetuses. The effects of sevoflurane on the translocation of 7 PKC isoforms (α, βI, βII, γ, δ, ɛ and ζ) were observed by immunoblotting using isoform-selective antibodies to PKCs. The treatment of neurons with sevoflurane induced the translocation of PKC α and PKC βII species from the cytosol to the membrane fraction, which indicated the activation of these PKC isoforms. In contrast, there was no clear change in the distribution of other PKC isoforms. We next examined whether the specific activation of PKC α and βII by sevoflurane could stimulate the MAP kinase signaling pathway in cultured neurons. Raf phosphorylation was increased by the administration of 0.25 mM sevoflurane. The phosphorylation of Raf proteins reached a maximum at 5–10 min. Subsequently, the phosphorylation of MEK proteins was increased at 10–15 min after sevoflurane treatments. That of ERK proteins was induced at 15–60 min. Moreover, the phosphorylation of ERK induced by sevoflurane was significantly decreased by the treatment of PKC inhibitor (staurosporine) and MEK inhibitor (PD98059). On the other hand, the contents of total Raf, MEK and ERK proteins were relatively constant at all times examined. To examine the ­localization of phosphorylated-ERK protein, immunohistochemical staining of sevoflurane-treated cultured neurons was performed. The phosphorylated-ERK proteins were markedly accumulated in both the cytosol of the cell body and the neurites in the neuronal cells with time after 0

  20. Mapping Cannabinoid 1 Receptor Allosteric Site(s): Critical Molecular Determinant and Signaling Profile of GAT100, a Novel, Potent, and Irreversibly Binding Probe.

    PubMed

    Laprairie, Robert B; Kulkarni, Abhijit R; Kulkarni, Pushkar M; Hurst, Dow P; Lynch, Diane; Reggio, Patricia H; Janero, David R; Pertwee, Roger G; Stevenson, Lesley A; Kelly, Melanie E M; Denovan-Wright, Eileen M; Thakur, Ganesh A

    2016-06-15

    One of the most abundant G-protein coupled receptors (GPCRs) in brain, the cannabinoid 1 receptor (CB1R), is a tractable therapeutic target for treating diverse psychobehavioral and somatic disorders. Adverse on-target effects associated with small-molecule CB1R orthosteric agonists and inverse agonists/antagonists have plagued their translational potential. Allosteric CB1R modulators offer a potentially safer modality through which CB1R signaling may be directed for therapeutic benefit. Rational design of candidate, druglike CB1R allosteric modulators requires greater understanding of the architecture of the CB1R allosteric endodomain(s) and the capacity of CB1R allosteric ligands to tune the receptor's information output. We have recently reported the synthesis of a focused library of rationally designed, covalent analogues of Org27569 and PSNCBAM-1, two prototypic CB1R negative allosteric modulators (NAMs). Among the novel, pharmacologically active CB1R NAMs reported, the isothiocyanate GAT100 emerged as the lead by virtue of its exceptional potency in the [(35)S]GTPγS and β-arrestin signaling assays and its ability to label CB1R as a covalent allosteric probe with significantly reduced inverse agonism in the [(35)S]GTPγS assay as compared to Org27569. We report here a comprehensive functional profiling of GAT100 across an array of important downstream cell-signaling pathways and analysis of its potential orthosteric probe-dependence and signaling bias. The results demonstrate that GAT100 is a NAM of the orthosteric CB1R agonist CP55,940 and the endocannabinoids 2-arachidonoylglycerol and anandamide for β-arrestin1 recruitment, PLCβ3 and ERK1/2 phosphorylation, cAMP accumulation, and CB1R internalization in HEK293A cells overexpressing CB1R and in Neuro2a and STHdh(Q7/Q7) cells endogenously expressing CB1R. Distinctively, GAT100 was a more potent and efficacious CB1R NAM than Org27569 and PSNCBAM-1 in all signaling assays and did not exhibit the inverse

  1. Cosmic statistics of statistics

    NASA Astrophysics Data System (ADS)

    Szapudi, István; Colombi, Stéphane; Bernardeau, Francis

    1999-12-01

    The errors on statistics measured in finite galaxy catalogues are exhaustively investigated. The theory of errors on factorial moments by Szapudi & Colombi is applied to cumulants via a series expansion method. All results are subsequently extended to the weakly non-linear regime. Together with previous investigations this yields an analytic theory of the errors for moments and connected moments of counts in cells from highly non-linear to weakly non-linear scales. For non-linear functions of unbiased estimators, such as the cumulants, the phenomenon of cosmic bias is identified and computed. Since it is subdued by the cosmic errors in the range of applicability of the theory, correction for it is inconsequential. In addition, the method of Colombi, Szapudi & Szalay concerning sampling effects is generalized, adapting the theory for inhomogeneous galaxy catalogues. While previous work focused on the variance only, the present article calculates the cross-correlations between moments and connected moments as well for a statistically complete description. The final analytic formulae representing the full theory are explicit but somewhat complicated. Therefore we have made available a fortran program capable of calculating the described quantities numerically (for further details e-mail SC at colombi@iap.fr). An important special case is the evaluation of the errors on the two-point correlation function, for which this should be more accurate than any method put forward previously. This tool will be immensely useful in the future for assessing the precision of measurements from existing catalogues, as well as aiding the design of new galaxy surveys. To illustrate the applicability of the results and to explore the numerical aspects of the theory qualitatively and quantitatively, the errors and cross-correlations are predicted under a wide range of assumptions for the future Sloan Digital Sky Survey. The principal results concerning the cumulants ξ, Q3 and Q4 is that

  2. TGF-β1 inhibition of IFN-γ-induced signaling and Th1 gene expression in CD4+ T cells is Smad3 independent but MAP kinase dependent

    PubMed Central

    Park, Il-Kyoo; Letterio, John J.; Gorham, James D.

    2007-01-01

    In addition to classic Smad signaling pathways, the pleiotropic immunoregulatory cytokine TGF-β1 can activate MAP kinases, but a role for TGF-β1-MAP kinase pathways in T cells has not been defined heretofore. We have shown previously that TGF-β1 inhibits Th1 development by inhibiting IFN-γ’s induction of T-bet and other Th1 differentiation genes, and that TGF-β1 inhibits receptor-proximal IFN-γ-Jak-Stat signaling responses. We now show that these effects of TGF-β1 are independent of the canonical TGF-β1 signaling module Smad3, but involve a specific MAP kinase pathway. In primary T cells, TGF-β1 activated the MEK/ERK and p38 MAP kinase pathways, but not the JNK pathway. Inhibition of the MEK/ERK pathway completely eliminated the inhibitory effects of TGF-β1 on IFN-γ responses in T cells, whereas inhibition of the p38 pathway had no effect. Thus, TGF-β1’s inhibition of IFN-γ signaling in T cells is mediated through a highly specific Smad3-independent, MEK/ERK-dependent signaling pathway. PMID:17403540

  3. Molecular mapping of signals in the Qa-2 antigen required for attachment of the phosphatidylinositol membrane anchor.

    PubMed Central

    Waneck, G L; Sherman, D H; Kincade, P W; Low, M G; Flavell, R A

    1988-01-01

    Proteins anchored in the membrane by covalent linkage to phosphatidylinositol (PtdIns) can be released by treatment with purified PtdIns-specific phospholipase C (Ptd-Ins-PLC). A recent survey of leukocyte antigens using flow cytometry has shown that staining of certain Qa antigens was diminished after PtdIns-PLC treatment, but staining of structurally related H-2 antigens was not affected. Therefore, in this study, the sensitivity of cell-surface Qa-2, H-2Kb, and H-2Db to hydrolysis by PtdIns-PLC was investigated biochemically by immunoprecipitation of radioiodinated molecules from cell lysates or supernatants. Qa-2, but not H-2Kb, was released from the surface of PtdIns-PLC-treated C57BL/10 mouse spleen cells and recovered in the cell supernatants. Similar analysis of thymoma cells transfected with cloned C57BL/10 genes showed that cell-surface Qa-2 molecules encoded by a Q7b cDNA and the Q7b or Q9b gene were sensitive to hydrolysis by PtdIns-PLC, whereas the H-2Kb and H-2Db gene products were resistant. Using thymoma cells transfected with hybrid genes constructed by exchanging exons between Q7b and H-2Db, the signals for PtdIns modification were localized to a defined region of Qa-2. This region differs from H-2Db most significantly by the presence of a central aspartate residue in the transmembrane segment and in the length of the cytoplasmic portion. Images PMID:3422441

  4. Blackberry extract inhibits UVB-induced oxidative damage and inflammation through MAP kinases and NF-κB signaling pathways in SKH-1 mice skin.

    PubMed

    Divya, Sasidharan Padmaja; Wang, Xin; Pratheeshkumar, Poyil; Son, Young-Ok; Roy, Ram Vinod; Kim, Donghern; Dai, Jin; Hitron, John Andrew; Wang, Lei; Asha, Padmaja; Shi, Xianglin; Zhang, Zhuo

    2015-04-01

    Extensive exposure of solar ultraviolet-B (UVB) radiation to skin induces oxidative stress and inflammation that play a crucial role in the induction of skin cancer. Photochemoprevention with natural products represents a simple but very effective strategy for the management of cutaneous neoplasia. In this study, we investigated whether blackberry extract (BBE) reduces chronic inflammatory responses induced by UVB irradiation in SKH-1 hairless mice skin. Mice were exposed to UVB radiation (100 mJ/cm(2)) on alternate days for 10 weeks, and BBE (10% and 20%) was applied topically a day before UVB exposure. Our results show that BBE suppressed UVB-induced hyperplasia and reduced infiltration of inflammatory cells in the SKH-1 hairless mice skin. BBE treatment reduced glutathione (GSH) depletion, lipid peroxidation (LPO), and myeloperoxidase (MPO) in mouse skin by chronic UVB exposure. BBE significantly decreased the level of pro-inflammatory cytokines IL-6 and TNF-α in UVB-exposed skin. Likewise, UVB-induced inflammatory responses were diminished by BBE as observed by a remarkable reduction in the levels of phosphorylated MAP Kinases, Erk1/2, p38, JNK1/2 and MKK4. Furthermore, BBE also reduced inflammatory mediators such as cyclooxygenase-2 (COX-2), prostaglandin E2 (PGE2), and inducible nitric oxide synthase (iNOS) levels in UVB-exposed skin. Treatment with BBE inhibited UVB-induced nuclear translocation of NF-κB and degradation of IκBα in mouse skin. Immunohistochemistry analysis revealed that topical application of BBE inhibited the expression of 8-oxo-7, 8-dihydro-2'-deoxyguanosine (8-oxodG), cyclobutane pyrimidine dimers (CPD), proliferating cell nuclear antigen (PCNA), and cyclin D1 in UVB-exposed skin. Collectively, these data indicate that BBE protects from UVB-induced oxidative damage and inflammation by modulating MAP kinase and NF-κB signaling pathways.

  5. Blackberry extract inhibits UVB-induced oxidative damage and inflammation through MAP kinases and NF-κB signalling pathways in SKH-1 mice skin

    PubMed Central

    Son, Young-Ok; Roy, Ram Vinod; Kim, Donghern; Dai, Jin; Hitron, John Andrew; Wang, Lei; Asha, Padmaja; Shi, Xianglin; Zhang, Zhuo

    2015-01-01

    Extensive exposure of solar ultraviolet-B (UVB) radiation to skin induces oxidative stress and inflammation that play a crucial role in the induction of skin cancer. Photochemoprevention with natural products represents a simple but very effective strategy for the management of cutaneous neoplasia. In this study, we investigated whether blackberry extract (BBE) reduces chronic inflammatory responses induced by UVB irradiation in SKH-1 hairless mice skin. Mice were exposed to UVB radiation (100 mJ/cm2) on alternate days for 10 weeks, and BBE (10% and 20%) was applied topically a day before UVB exposure. Our results show that BBE suppressed UVB-induced hyperplasia and reduced infiltration of inflammatory cells in the SKH-1 hairless mice skin. BBE treatment reduced glutathione (GSH) depletion, lipid peroxidation (LPO), and myeloperoxidase (MPO) in mouse skin by chronic UVB exposure. BBE significantly decreased the level of pro-inflammatory cytokines IL-6 and TNF-α in UVB-exposed skin. Likewise, UVB-induced inflammatory responses were diminished by BBE as observed by a remarkable reduction in the levels of phosphorylated MAP Kinases, Erk1/2, p38, JNK1/2 and MKK4. Furthermore, BBE also reduced inflammatory mediators such as cyclooxygenase-2 (COX-2), prostaglandin E2 (PGE2), and inducible nitric oxide synthase (iNOS) levels in UVB-exposed skin. Treatment with BBE inhibited UVB-induced nuclear translocation of NF-κB and degradation of IκBα in mouse skin. Immunohistochemistry analysis revealed that topical application of BBE inhibited the expression of 8-oxo-7, 8-dihydro-2'-deoxyguanosine (8-oxodG), cyclobutane pyrimidine dimers (CPD), proliferating cell nuclear antigen (PCNA), and cyclin D1 in UVB-exposed skin. Collectively, these data indicates that BBE protects from UVB-induced oxidative damage and inflammation by modulating MAP kinase and NF-κB signaling pathways. PMID:25680589

  6. Mapping changes in agricultural cropping frequency across Zimbabwe using cross-scale time-series remote sensing data and a novel signal decomposition method

    NASA Astrophysics Data System (ADS)

    Khandelwal, A.; Van Den Hoek, J.; Sedano, F.; Kumar, V.; Tucker, C. J.

    2014-12-01

    A central challenge in agricultural remote sensing is the detection of changes in intra-annual cropping frequency, often necessary in monitoring crop productivity, agricultural management practices, or policy implementation. Though remote sensing imagery offers synoptic and systematic measurements relevant to monitoring crop phenology across spatial scales, broad-scale (i.e., country-wide) changes in cropping frequency have seldom been quantified due to spatio-temporal heterogeneity in phenological and climatic cycles, signal noise, and missing data resulting from cloud cover. For example, in Zimbabwe, once the breadbasket of southern Africa, large-scale changes to agricultural production followed land distribution policies introduced in the early 2000s. The diverse impacts of land reform on the agricultural economy continue to be debated yet the underlying changes in cropping frequency and pattern have never been systematically assessed. Using Zimbabwean agriculture as a case study and MODIS 16-day composite Normalized Difference Vegetation Index (NDVI) and complementary Landsat imagery collected since 2000 across Zimbabwe, this presentation introduces a novel time-series signal decomposition and spatiotemporal clustering approach to map intra-annual cropping frequency and changes therein. MODIS-derived results indicate a massive decline in double-cropped acreage since 2000, a complete overhaul of cropping pattern with the disaggregation of large-scale commercial farms into multiple smallholder plots, and a spatial contraction of double-cropped fields to peri-urban lands, while Landsat trends capture the recent emergence of small-scale double-cropping systems unseen in MODIS data. These findings provide an independent and objective assessment of field-level changes in agricultural productivity, spatiotemporally explicit land reform effects on large-scale as well as smallholder agriculture and potential for food production, and have importance for regional water

  7. An automated normative-based fluorodeoxyglucose positron emission tomography image-analysis procedure to aid Alzheimer disease diagnosis using statistical parametric mapping and interactive image display

    NASA Astrophysics Data System (ADS)

    Chen, Kewei; Ge, Xiaolin; Yao, Li; Bandy, Dan; Alexander, Gene E.; Prouty, Anita; Burns, Christine; Zhao, Xiaojie; Wen, Xiaotong; Korn, Ronald; Lawson, Michael; Reiman, Eric M.

    2006-03-01

    Having approved fluorodeoxyglucose positron emission tomography (FDG PET) for the diagnosis of Alzheimer's disease (AD) in some patients, the Centers for Medicare and Medicaid Services suggested the need to develop and test analysis techniques to optimize diagnostic accuracy. We developed an automated computer package comparing an individual's FDG PET image to those of a group of normal volunteers. The normal control group includes FDG-PET images from 82 cognitively normal subjects, 61.89+/-5.67 years of age, who were characterized demographically, clinically, neuropsychologically, and by their apolipoprotein E genotype (known to be associated with a differential risk for AD). In addition, AD-affected brain regions functionally defined as based on a previous study (Alexander, et al, Am J Psychiatr, 2002) were also incorporated. Our computer package permits the user to optionally select control subjects, matching the individual patient for gender, age, and educational level. It is fully streamlined to require minimal user intervention. With one mouse click, the program runs automatically, normalizing the individual patient image, setting up a design matrix for comparing the single subject to a group of normal controls, performing the statistics, calculating the glucose reduction overlap index of the patient with the AD-affected brain regions, and displaying the findings in reference to the AD regions. In conclusion, the package automatically contrasts a single patient to a normal subject database using sound statistical procedures. With further validation, this computer package could be a valuable tool to assist physicians in decision making and communicating findings with patients and patient families.

  8. Dosage of Dyrk1a shifts cells within a p21-cyclin D1 signaling map to control the decision to enter the cell cycle.

    PubMed

    Chen, Jia-Yun; Lin, Jia-Ren; Tsai, Feng-Chiao; Meyer, Tobias

    2013-10-10

    Mammalian cells have a remarkable capacity to compensate for heterozygous gene loss or extra gene copies. One exception is Down syndrome (DS), where a third copy of chromosome 21 mediates neurogenesis defects and lowers the frequency of solid tumors. Here we combine live-cell imaging and single-cell analysis to show that increased dosage of chromosome 21-localized Dyrk1a steeply increases G1 cell cycle duration through direct phosphorylation and degradation of cyclin D1 (CycD1). DS-derived fibroblasts showed analogous cell cycle changes that were reversed by Dyrk1a inhibition. Furthermore, reducing Dyrk1a activity increased CycD1 expression to force a bifurcation, with one subpopulation of cells accelerating proliferation and the other arresting proliferation by costabilizing CycD1 and the CDK inhibitor p21. Thus, dosage of Dyrk1a repositions cells within a p21-CycD1 signaling map, directing each cell to either proliferate or to follow two distinct cell cycle exit pathways characterized by high or low CycD1 and p21 levels. PMID:24119401

  9. Statistical downscaling for daily precipitation in Korea using combined PRISM, RCM, and quantile mapping: Part 1, methodology and evaluation in historical simulation

    NASA Astrophysics Data System (ADS)

    Kim, Maeng-Ki; Kim, Seonae; Kim, Jinuk; Heo, Jin; Park, Jeong-Soo; Kwon, Won-Tae; Suh, Myoung-Seok

    2016-05-01

    In this study, we present the Parameter-elevation Relationships on Independent Slopes Model (PRISM)-based Dynamic downscaling Error correction (PRIDE) model, which is suitable for complex topographies, such as the Korean peninsula. The PRIDE model is constructed by combining the PRISM module, the Regional Climate Model (RCM) anomaly, and quantile mapping (QM) to produce high-resolution (1 km) grid data at a daily time scale. The results show that the systematic bias of the RCM was significantly reduced by simply substituting the climatological observational seasonal cycle at a daily timescale for each grid point obtained from the PRISM. QM was then applied to correct additional systematic bias by constructing the transfer functions under the cumulative density function framework between the model and observation using six types of transfer functions. K-fold cross-validation of the PRIDE model shows that the number of modeled precipitation days is approximately 90~121% of the number of observed precipitation days for the five daily precipitation classes, indicating that the PRIDE model reasonably estimates the observational frequency of daily precipitation under a quantile framework. The relative Mean Absolute Error (MAE) is also discussed in the framework of the intensity of daily precipitation.

  10. Laboratory for Engineering Man/Machine Systems (LEMS): System identification, model reduction and deconvolution filtering using Fourier based modulating signals and high order statistics

    NASA Technical Reports Server (NTRS)

    Pan, Jianqiang

    1992-01-01

    Several important problems in the fields of signal processing and model identification, such as system structure identification, frequency response determination, high order model reduction, high resolution frequency analysis, deconvolution filtering, and etc. Each of these topics involves a wide range of applications and has received considerable attention. Using the Fourier based sinusoidal modulating signals, it is shown that a discrete autoregressive model can be constructed for the least squares identification of continuous systems. Some identification algorithms are presented for both SISO and MIMO systems frequency response determination using only transient data. Also, several new schemes for model reduction were developed. Based upon the complex sinusoidal modulating signals, a parametric least squares algorithm for high resolution frequency estimation is proposed. Numerical examples show that the proposed algorithm gives better performance than the usual. Also, the problem was studied of deconvolution and parameter identification of a general noncausal nonminimum phase ARMA system driven by non-Gaussian stationary random processes. Algorithms are introduced for inverse cumulant estimation, both in the frequency domain via the FFT algorithms and in the domain via the least squares algorithm.

  11. An overview of data acquisition, signal coding and data analysis techniques for MST radars

    NASA Technical Reports Server (NTRS)

    Rastogi, P. K.

    1986-01-01

    An overview is given of the data acquisition, signal processing, and data analysis techniques that are currently in use with high power MST/ST (mesosphere stratosphere troposphere/stratosphere troposphere) radars. This review supplements the works of Rastogi (1983) and Farley (1984) presented at previous MAP workshops. A general description is given of data acquisition and signal processing operations and they are characterized on the basis of their disparate time scales. Then signal coding, a brief description of frequently used codes, and their limitations are discussed, and finally, several aspects of statistical data processing such as signal statistics, power spectrum and autocovariance analysis, outlier removal techniques are discussed.

  12. Optimizing and Interpreting Insular Functional Connectivity Maps Obtained During Acute Experimental Pain: The Effects of Global Signal and Task Paradigm Regression.

    PubMed

    Ibinson, James W; Vogt, Keith M; Taylor, Kevin B; Dua, Shiv B; Becker, Christopher J; Loggia, Marco; Wasan, Ajay D

    2015-12-01

    The insula is uniquely located between the temporal and parietal cortices, making it anatomically well-positioned to act as an integrating center between the sensory and affective domains for the processing of painful stimulation. This can be studied through resting-state functional connectivity (fcMRI) imaging; however, the lack of a clear methodology for the analysis of fcMRI complicates the interpretation of these data during acute pain. Detected connectivity changes may reflect actual alterations in low-frequency synchronous neuronal activity related to pain, may be due to changes in global cerebral blood flow or the superimposed task-induced neuronal activity. The primary goal of this study was to investigate the effects of global signal regression (GSR) and task paradigm regression (TPR) on the changes in functional connectivity of the left (contralateral) insula in healthy subjects at rest and during acute painful electric nerve stimulation of the right hand. The use of GSR reduced the size and statistical significance of connectivity clusters and created negative correlation coefficients for some connectivity clusters. TPR with cyclic stimulation gave task versus rest connectivity differences similar to those with a constant task, suggesting that analysis which includes TPR is more accurately reflective of low-frequency neuronal activity. Both GSR and TPR have been inconsistently applied to fcMRI analysis. Based on these results, investigators need to consider the impact GSR and TPR have on connectivity during task performance when attempting to synthesize the literature.

  13. Blackberry extract inhibits UVB-induced oxidative damage and inflammation through MAP kinases and NF-κB signaling pathways in SKH-1 mice skin

    SciTech Connect

    Divya, Sasidharan Padmaja; Wang, Xin; Pratheeshkumar, Poyil; Son, Young-Ok; Roy, Ram Vinod; Kim, Donghern; Dai, Jin; Hitron, John Andrew; Wang, Lei; Asha, Padmaja; Shi, Xianglin; Zhang, Zhuo

    2015-04-01

    Extensive exposure of solar ultraviolet-B (UVB) radiation to skin induces oxidative stress and inflammation that play a crucial role in the induction of skin cancer. Photochemoprevention with natural products represents a simple but very effective strategy for the management of cutaneous neoplasia. In this study, we investigated whether blackberry extract (BBE) reduces chronic inflammatory responses induced by UVB irradiation in SKH-1 hairless mice skin. Mice were exposed to UVB radiation (100 mJ/cm{sup 2}) on alternate days for 10 weeks, and BBE (10% and 20%) was applied topically a day before UVB exposure. Our results show that BBE suppressed UVB-induced hyperplasia and reduced infiltration of inflammatory cells in the SKH-1 hairless mice skin. BBE treatment reduced glutathione (GSH) depletion, lipid peroxidation (LPO), and myeloperoxidase (MPO) in mouse skin by chronic UVB exposure. BBE significantly decreased the level of pro-inflammatory cytokines IL-6 and TNF-α in UVB-exposed skin. Likewise, UVB-induced inflammatory responses were diminished by BBE as observed by a remarkable reduction in the levels of phosphorylated MAP Kinases, Erk1/2, p38, JNK1/2 and MKK4. Furthermore, BBE also reduced inflammatory mediators such as cyclooxygenase-2 (COX-2), prostaglandin E{sub 2} (PGE{sub 2}), and inducible nitric oxide synthase (iNOS) levels in UVB-exposed skin. Treatment with BBE inhibited UVB-induced nuclear translocation of NF-κB and degradation of IκBα in mouse skin. Immunohistochemistry analysis revealed that topical application of BBE inhibited the expression of 8-oxo-7, 8-dihydro-2′-deoxyguanosine (8-oxodG), cyclobutane pyrimidine dimers (CPD), proliferating cell nuclear antigen (PCNA), and cyclin D1 in UVB-exposed skin. Collectively, these data indicate that BBE protects from UVB-induced oxidative damage and inflammation by modulating MAP kinase and NF-κB signaling pathways. - Highlights: • Blackberry extract inhibits UVB-induced glutathione depletion.

  14. High-resolution habitat mapping on mud fields: new approach to quantitative mapping of Ocean quahog.

    PubMed

    Isachenko, Artem; Gubanova, Yana; Tzetlin, Alexander; Mokievsky, Vadim

    2014-12-01

    During 2009-2012 stocks of the bivalve Arctica islandica (Linnaeus, 1767) (Ocean quahog) in Kandalaksha Bay (the White Sea) has been assessed using a side-scan sonar, grab sampling and underwater photo imaging. Structurally uniform localities were highlighted on the basis of side-scan signal. Each type of a signal reflects combination of sediment type, microtopography and structural characteristics of benthic community. The distribution of A. islandica was the predominant factor in determining community structure. Seabed attributes considered most significant were defined for each type of substrate type. Relations of sonar signal and sediment type were used for landscape mapping based on sonar data. Community characteristics at known localities were reliably interpolated to the area of survey using statistical processing of geophysical data. A method of integrated sonar and sampling data interpretation for high-resolution mapping of A. islandica by biomass groups, benthic faunal groups and associated habitats was developed.

  15. Morbidity statistics

    PubMed Central

    Smith, Alwyn

    1969-01-01

    This paper is based on an analysis of questionnaires sent to the health ministries of Member States of WHO asking for information about the extent, nature, and scope of morbidity statistical information. It is clear that most countries collect some statistics of morbidity and many countries collect extensive data. However, few countries relate their collection to the needs of health administrators for information, and many countries collect statistics principally for publication in annual volumes which may appear anything up to 3 years after the year to which they refer. The desiderata of morbidity statistics may be summarized as reliability, representativeness, and relevance to current health problems. PMID:5306722

  16. Prospective active marker motion correction improves statistical power in BOLD fMRI.

    PubMed

    Muraskin, Jordan; Ooi, Melvyn B; Goldman, Robin I; Krueger, Sascha; Thomas, William J; Sajda, Paul; Brown, Truman R

    2013-03-01

    Group level statistical maps of blood oxygenation level dependent (BOLD) signals acquired using functional magnetic resonance imaging (fMRI) have become a basic measurement for much of systems, cognitive and social neuroscience. A challenge in making inferences from these statistical maps is the noise and potential confounds that arise from the head motion that occurs within and between acquisition volumes. This motion results in the scan plane being misaligned during acquisition, ultimately leading to reduced statistical power when maps are constructed at the group level. In most cases, an attempt is made to correct for this motion through the use of retrospective analysis methods. In this paper, we use a prospective active marker motion correction (PRAMMO) system that uses radio frequency markers for real-time tracking of motion, enabling on-line slice plane correction. We show that the statistical power of the activation maps is substantially increased using PRAMMO compared to conventional retrospective correction. Analysis of our results indicates that the PRAMMO acquisition reduces the variance without decreasing the signal component of the BOLD (beta). Using PRAMMO could thus improve the overall statistical power of fMRI based BOLD measurements, leading to stronger inferences of the nature of processing in the human brain.

  17. Statistical Diversions

    ERIC Educational Resources Information Center

    Petocz, Peter; Sowey, Eric

    2012-01-01

    The term "data snooping" refers to the practice of choosing which statistical analyses to apply to a set of data after having first looked at those data. Data snooping contradicts a fundamental precept of applied statistics, that the scheme of analysis is to be planned in advance. In this column, the authors shall elucidate the statistical…

  18. Comparing and combining the Saskatoon, QMAP, and COBE CMB maps

    SciTech Connect

    Xu, Yongzhong; Tegmark, Max; de Oliveira-Costa, Angelica; Devlin, Mark J.; Herbig, Thomas; Miller, Amber D.; Netterfield, C. Barth; Page, Lyman

    2001-05-15

    We present a method for comparing and combining maps with different resolutions and beam shapes, and apply it to the Saskatoon, QMAP, and COBE-DMR data sets. Although the Saskatoon and QMAP maps detect signals at the 21{sigma} and 40{sigma} levels, respectively, their difference is consistent with pure noise, placing strong limits on possible systematic errors. In particular, we obtain quantitative upper limits on relative calibration and pointing errors. Splitting the combined data by frequency shows similar consistency between the Ka and Q bands, placing limits on foreground contamination. The visual agreement between the maps is equally striking. Our combined QMAP+Saskatoon map, nicknamed QMASK, is publicly available on the web together with its 6495x6495 noise covariance matrix. This thoroughly tested data set covers a large enough area (648 square degrees -- currently the largest degree-scale map available) to allow a statistical comparison with COBE-DMR, showing good agreement.

  19. Statistics Clinic

    NASA Technical Reports Server (NTRS)

    Feiveson, Alan H.; Foy, Millennia; Ploutz-Snyder, Robert; Fiedler, James

    2014-01-01

    Do you have elevated p-values? Is the data analysis process getting you down? Do you experience anxiety when you need to respond to criticism of statistical methods in your manuscript? You may be suffering from Insufficient Statistical Support Syndrome (ISSS). For symptomatic relief of ISSS, come for a free consultation with JSC biostatisticians at our help desk during the poster sessions at the HRP Investigators Workshop. Get answers to common questions about sample size, missing data, multiple testing, when to trust the results of your analyses and more. Side effects may include sudden loss of statistics anxiety, improved interpretation of your data, and increased confidence in your results.

  20. Defect mapping system

    DOEpatents

    Sopori, B.L.

    1995-04-11

    Apparatus for detecting and mapping defects in the surfaces of polycrystalline materials in a manner that distinguishes dislocation pits from grain boundaries includes a laser for illuminating a wide spot on the surface of the material, a light integrating sphere with apertures for capturing light scattered by etched dislocation pits in an intermediate range away from specular reflection while allowing light scattered by etched grain boundaries in a near range from specular reflection to pass through, and optical detection devices for detecting and measuring intensities of the respective intermediate scattered light and near specular scattered light. A center blocking aperture or filter can be used to screen out specular reflected light, which would be reflected by nondefect portions of the polycrystalline material surface. An X-Y translation stage for mounting the polycrystalline material and signal processing and computer equipment accommodate rastor mapping, recording, and displaying of respective dislocation and grain boundary defect densities. A special etch procedure is included, which prepares the polycrystalline material surface to produce distinguishable intermediate and near specular light scattering in patterns that have statistical relevance to the dislocation and grain boundary defect densities. 20 figures.

  1. Defect mapping system

    DOEpatents

    Sopori, Bhushan L.

    1995-01-01

    Apparatus for detecting and mapping defects in the surfaces of polycrystalline materials in a manner that distinguishes dislocation pits from grain boundaries includes a laser for illuminating a wide spot on the surface of the material, a light integrating sphere with apertures for capturing light scattered by etched dislocation pits in an intermediate range away from specular reflection while allowing light scattered by etched grain boundaries in a near range from specular reflection to pass through, and optical detection devices for detecting and measuring intensities of the respective intermediate scattered light and near specular scattered light. A center blocking aperture or filter can be used to screen out specular reflected light, which would be reflected by nondefect portions of the polycrystalline material surface. An X-Y translation stage for mounting the polycrystalline material and signal processing and computer equipment accommodate rastor mapping, recording, and displaying of respective dislocation and grain boundary defect densities. A special etch procedure is included, which prepares the polycrystalline material surface to produce distinguishable intermediate and near specular light scattering in patterns that have statistical relevance to the dislocation and grain boundary defect densities.

  2. SEER Statistics

    Cancer.gov

    The Surveillance, Epidemiology, and End Results (SEER) Program of the National Cancer Institute works to provide information on cancer statistics in an effort to reduce the burden of cancer among the U.S. population.

  3. Cancer Statistics

    MedlinePlus

    ... cancer statistics across the world. U.S. Cancer Mortality Trends The best indicator of progress against cancer is ... the number of cancer survivors has increased. These trends show that progress is being made against the ...

  4. Statistical Physics

    NASA Astrophysics Data System (ADS)

    Hermann, Claudine

    Statistical Physics bridges the properties of a macroscopic system and the microscopic behavior of its constituting particles, otherwise impossible due to the giant magnitude of Avogadro's number. Numerous systems of today's key technologies - such as semiconductors or lasers - are macroscopic quantum objects; only statistical physics allows for understanding their fundamentals. Therefore, this graduate text also focuses on particular applications such as the properties of electrons in solids with applications, and radiation thermodynamics and the greenhouse effect.

  5. Statistical properties of an iterated arithmetic mapping

    SciTech Connect

    Feix, M.R.; Rouet, J.L.

    1994-07-01

    We study the (3x = 1)/2 problem from a probabilistic viewpoint and show a forgetting mechanism for the last k binary digits of the seed after k iterations. The problem is subsequently generalized to a trifurcation process, the (lx + m)/3 problem. Finally the sequence of a set of seeds is empirically shown to be equivalent to a random walk of the variable log{sub 2}x (or log{sub 3} x) though computer simulations.

  6. Phosphodiesterase MoPdeH targets MoMck1 of the conserved mitogen-activated protein (MAP) kinase signalling pathway to regulate cell wall integrity in rice blast fungus Magnaporthe oryzae.

    PubMed

    Yin, Ziyi; Tang, Wei; Wang, Jingzhen; Liu, Xinyu; Yang, Lina; Gao, Chuyun; Zhang, Jinlong; Zhang, Haifeng; Zheng, Xiaobo; Wang, Ping; Zhang, Zhengguang

    2016-06-01

    In the rice blast fungus Magnaporthe oryzae, the high-affinity cyclic adenosine monophosphate (cAMP) phosphodiesterase MoPdeH is important not only for cAMP signalling and pathogenicity, but also for cell wall integrity (CWI) maintenance through an unknown mechanism. By utilizing affinity purification, we found that MoPdeH interacts with MoMck1, one of the components of the mitogen-activated protein (MAP) kinase cascade that regulates CWI. Overexpression of MoMCK1 suppressed defects in autolysis and pathogenicity of the ΔMopdeH mutant, although partially, suggesting that MoPdeH plays a critical role in CWI maintenance mediated by the MAP kinase pathway. We found that MoMck1 and two other MAP kinase cascade components, MoMkk1 and MoMps1, modulate intracellular cAMP levels by regulating the expression of MoPDEH through a feedback loop. In addition, disruption of MoMKK1 resulted in less aerial hyphal formation, defective asexual development and attenuated pathogenicity. Moreover, MoMkk1 plays a role in the response to osmotic stress via regulation of MoOsm1 phosphorylation levels, whereas endoplasmic reticulum (ER) stress enhances MoMps1 phosphorylation and loss of the MAP kinase cascade component affects the unfolded protein response (UPR) pathway. Taken together, our findings demonstrate that MoPdeH functions upstream of the MoMck1-MoMkk1-MoMps1 MAP kinase pathway to regulate CWI, and that MoPdeH also mediates crosstalk between the cAMP signalling pathway, the osmotic sensing high osmolarity glycerol (HOG) pathway and the dithiothreitol (DTT)-induced UPR pathway in M. oryzae.

  7. Phosphodiesterase MoPdeH targets MoMck1 of the conserved mitogen-activated protein (MAP) kinase signalling pathway to regulate cell wall integrity in rice blast fungus Magnaporthe oryzae.

    PubMed

    Yin, Ziyi; Tang, Wei; Wang, Jingzhen; Liu, Xinyu; Yang, Lina; Gao, Chuyun; Zhang, Jinlong; Zhang, Haifeng; Zheng, Xiaobo; Wang, Ping; Zhang, Zhengguang

    2016-06-01

    In the rice blast fungus Magnaporthe oryzae, the high-affinity cyclic adenosine monophosphate (cAMP) phosphodiesterase MoPdeH is important not only for cAMP signalling and pathogenicity, but also for cell wall integrity (CWI) maintenance through an unknown mechanism. By utilizing affinity purification, we found that MoPdeH interacts with MoMck1, one of the components of the mitogen-activated protein (MAP) kinase cascade that regulates CWI. Overexpression of MoMCK1 suppressed defects in autolysis and pathogenicity of the ΔMopdeH mutant, although partially, suggesting that MoPdeH plays a critical role in CWI maintenance mediated by the MAP kinase pathway. We found that MoMck1 and two other MAP kinase cascade components, MoMkk1 and MoMps1, modulate intracellular cAMP levels by regulating the expression of MoPDEH through a feedback loop. In addition, disruption of MoMKK1 resulted in less aerial hyphal formation, defective asexual development and attenuated pathogenicity. Moreover, MoMkk1 plays a role in the response to osmotic stress via regulation of MoOsm1 phosphorylation levels, whereas endoplasmic reticulum (ER) stress enhances MoMps1 phosphorylation and loss of the MAP kinase cascade component affects the unfolded protein response (UPR) pathway. Taken together, our findings demonstrate that MoPdeH functions upstream of the MoMck1-MoMkk1-MoMps1 MAP kinase pathway to regulate CWI, and that MoPdeH also mediates crosstalk between the cAMP signalling pathway, the osmotic sensing high osmolarity glycerol (HOG) pathway and the dithiothreitol (DTT)-induced UPR pathway in M. oryzae. PMID:27193947

  8. Mutations in MAP3K1 Cause 46,XY Disorders of Sex Development and Implicate a Common Signal Transduction Pathway in Human Testis Determination

    PubMed Central

    Pearlman, Alexander; Loke, Johnny; Le Caignec, Cedric; White, Stefan; Chin, Lisa; Friedman, Andrew; Warr, Nicholas; Willan, John; Brauer, David; Farmer, Charles; Brooks, Eric; Oddoux, Carole; Riley, Bridget; Shajahan, Shahin; Camerino, Giovanna; Homfray, Tessa; Crosby, Andrew H.; Couper, Jenny; David, Albert; Greenfield, Andy; Sinclair, Andrew; Ostrer, Harry

    2010-01-01

    Investigations of humans with disorders of sex development (DSDs) resulted in the discovery of many of the now-known mammalian sex-determining genes, including SRY, RSPO1, SOX9, NR5A1, WT1, NR0B1, and WNT4. Here, the locus for an autosomal sex-determining gene was mapped via linkage analysis in two families with 46,XY DSD to the long arm of chromosome 5 with a combined, multipoint parametric LOD score of 6.21. A splice-acceptor mutation (c.634-8T>A) in MAP3K1 segregated with the phenotype in the first family and disrupted RNA splicing. Mutations were demonstrated in the second family (p.Gly616Arg) and in two of 11 sporadic cases (p.Leu189Pro, p.Leu189Arg)—18% prevalence in this cohort of sporadic cases. In cultured primary lymphoblastoid cells from family 1 and the two sporadic cases, these mutations altered the phosphorylation of the downstream targets, p38 and ERK1/2, and enhanced binding of RHOA to the MAP3K1 complex. Map3k1 within the syntenic region was expressed in the embryonic mouse gonad prior to, and after, sex determination. Thus, mutations in MAP3K1 that result in 46,XY DSD with partial or complete gonadal dysgenesis implicate this pathway in normal human sex determination. PMID:21129722

  9. A statistical study of GPS loss of lock caused by ionospheric disturbances

    NASA Astrophysics Data System (ADS)

    Tsugawa, T.; Nishioka, M.; Otsuka, Y.; Saito, A.; Kato, H.; Kubota, M.; Nagatsuma, T.; Murata, K. T.

    2010-12-01

    Two-dimensional total electron content (TEC) maps have been derived from ground-based GPS receiver networks and applied to studies of various ionospheric disturbances since mid-1990s. For the purpose of monitoring and researching ionospheric disturbances which can degrade GNSS navigations and cause loss-of-lock on GNSS signals, National Institute of Information and Communications Technology (NICT), Japan has developed TEC maps over Japan using the dense GPS network, GEONET, which consists of more than 1,200 GPS receivers and is operated by Geophysical Survey Institute, Japan. Currently, we are providing two-dimensional maps of absolute TEC, detrended TEC with 60, 30, 15-minute window, rate of TEC change index (ROTI), and loss-of-lock (LOL) on GPS signal over Japan. These data and quick-look maps since 1997 are archived and available in the website of NICT (http://wdc.nict.go.jp/IONO/). Recently developed GPS receiver networks in North America and Europe make it possible to obtain regional TEC maps with higher spatial and temporal resolution than the global weighted mean TEC maps in the IONEX format provided by several institutes such as International GNSS Service (IGS) and another global TEC map provided by MIT Haystack observatory. Recently, we have also developed the regional TEC maps over North America and Europe. These data and quick-look maps are also available in the NICT website. In this presentation, we will show some severe ionospheric events such as high latitude storm-time plasma bubbles and storm enhanced density events observed over Japan using the GPS-TEC database. These events cause loss-of-lock of GPS signals and large GPS positioning errors. We also discuss about the statistical characteristics of LOL on the GPS signal caused by ionospheric disturbances.

  10. Digital Forensics Using Local Signal Statistics

    ERIC Educational Resources Information Center

    Pan, Xunyu

    2011-01-01

    With the rapid growth of the Internet and the popularity of digital imaging devices, digital imagery has become our major information source. Meanwhile, the development of digital manipulation techniques employed by most image editing software brings new challenges to the credibility of photographic images as the definite records of events. We…

  11. Statistical Signal Processing and the Motor Cortex

    PubMed Central

    Brockwell, A.E.; Kass, R.E.; Schwartz, A.B.

    2011-01-01

    Over the past few decades, developments in technology have significantly improved the ability to measure activity in the brain. This has spurred a great deal of research into brain function and its relation to external stimuli, and has important implications in medicine and other fields. As a result of improved understanding of brain function, it is now possible to build devices that provide direct interfaces between the brain and the external world. We describe some of the current understanding of function of the motor cortex region. We then discuss a typical likelihood-based state-space model and filtering based approach to address the problems associated with building a motor cortical-controlled cursor or robotic prosthetic device. As a variation on previous work using this approach, we introduce the idea of using Markov chain Monte Carlo methods for parameter estimation in this context. By doing this instead of performing maximum likelihood estimation, it is possible to expand the range of possible models that can be explored, at a cost in terms of computational load. We demonstrate results obtained applying this methodology to experimental data gathered from a monkey. PMID:21765538

  12. Bodily maps of emotions

    PubMed Central

    Nummenmaa, Lauri; Glerean, Enrico; Hari, Riitta; Hietanen, Jari K.

    2014-01-01

    Emotions are often felt in the body, and somatosensory feedback has been proposed to trigger conscious emotional experiences. Here we reveal maps of bodily sensations associated with different emotions using a unique topographical self-report method. In five experiments, participants (n = 701) were shown two silhouettes of bodies alongside emotional words, stories, movies, or facial expressions. They were asked to color the bodily regions whose activity they felt increasing or decreasing while viewing each stimulus. Different emotions were consistently associated with statistically separable bodily sensation maps across experiments. These maps were concordant across West European and East Asian samples. Statistical classifiers distinguished emotion-specific activation maps accurately, confirming independence of topographies across emotions. We propose that emotions are represented in the somatosensory system as culturally universal categorical somatotopic maps. Perception of these emotion-triggered bodily changes may play a key role in generating consciously felt emotions. PMID:24379370

  13. Bodily maps of emotions.

    PubMed

    Nummenmaa, Lauri; Glerean, Enrico; Hari, Riitta; Hietanen, Jari K

    2014-01-14

    Emotions are often felt in the body, and somatosensory feedback has been proposed to trigger conscious emotional experiences. Here we reveal maps of bodily sensations associated with different emotions using a unique topographical self-report method. In five experiments, participants (n = 701) were shown two silhouettes of bodies alongside emotional words, stories, movies, or facial expressions. They were asked to color the bodily regions whose activity they felt increasing or decreasing while viewing each stimulus. Different emotions were consistently associated with statistically separable bodily sensation maps across experiments. These maps were concordant across West European and East Asian samples. Statistical classifiers distinguished emotion-specific activation maps accurately, confirming independence of topographies across emotions. We propose that emotions are represented in the somatosensory system as culturally universal categorical somatotopic maps. Perception of these emotion-triggered bodily changes may play a key role in generating consciously felt emotions.

  14. Digital noise generators using one-dimensional chaotic maps

    SciTech Connect

    Martínez-Ñonthe, J. A; Palacios-Luengas, L.; Cruz-Irisson, M.; Vazquez Medina, R.; Díaz Méndez, J. A.

    2014-05-15

    This work shows how to improve the statistical distribution of signals produced by digital noise generators designed with one-dimensional (1-D) chaotic maps. It also shows that in a digital electronic design the piecewise linear chaotic maps (PWLCM) should be considered because they do not have stability islands in its chaotic behavior region, as it occurs in the case of the logistic map, which is commonly used to build noise generators. The design and implementation problems of the digital noise generators are analyzed and a solution is proposed. This solution relates the output of PWLCM, usually defined in the real numbers' domain, with a codebook of S elements, previously defined. The proposed solution scheme produces digital noise signals with a statistical distribution close to a uniform distribution. Finally, this work shows that it is possible to have control over the statistical distribution of the noise signal by selecting the control parameter of the PWLCM and using, as a design criterion, the bifurcation diagram.

  15. Statistical Optics

    NASA Astrophysics Data System (ADS)

    Goodman, Joseph W.

    2000-07-01

    The Wiley Classics Library consists of selected books that have become recognized classics in their respective fields. With these new unabridged and inexpensive editions, Wiley hopes to extend the life of these important works by making them available to future generations of mathematicians and scientists. Currently available in the Series: T. W. Anderson The Statistical Analysis of Time Series T. S. Arthanari & Yadolah Dodge Mathematical Programming in Statistics Emil Artin Geometric Algebra Norman T. J. Bailey The Elements of Stochastic Processes with Applications to the Natural Sciences Robert G. Bartle The Elements of Integration and Lebesgue Measure George E. P. Box & Norman R. Draper Evolutionary Operation: A Statistical Method for Process Improvement George E. P. Box & George C. Tiao Bayesian Inference in Statistical Analysis R. W. Carter Finite Groups of Lie Type: Conjugacy Classes and Complex Characters R. W. Carter Simple Groups of Lie Type William G. Cochran & Gertrude M. Cox Experimental Designs, Second Edition Richard Courant Differential and Integral Calculus, Volume I RIchard Courant Differential and Integral Calculus, Volume II Richard Courant & D. Hilbert Methods of Mathematical Physics, Volume I Richard Courant & D. Hilbert Methods of Mathematical Physics, Volume II D. R. Cox Planning of Experiments Harold S. M. Coxeter Introduction to Geometry, Second Edition Charles W. Curtis & Irving Reiner Representation Theory of Finite Groups and Associative Algebras Charles W. Curtis & Irving Reiner Methods of Representation Theory with Applications to Finite Groups and Orders, Volume I Charles W. Curtis & Irving Reiner Methods of Representation Theory with Applications to Finite Groups and Orders, Volume II Cuthbert Daniel Fitting Equations to Data: Computer Analysis of Multifactor Data, Second Edition Bruno de Finetti Theory of Probability, Volume I Bruno de Finetti Theory of Probability, Volume 2 W. Edwards Deming Sample Design in Business Research

  16. Dietary influence on MAPK-signaling pathways and risk of colon and rectal cancer

    PubMed Central

    Slattery, Martha L.; Lundgreen, Abbie; Wolff, Roger K.

    2014-01-01

    Mitogen-activated protein kinase (MAPK) pathways regulate cellular functions including cell proliferation, differentiation, migration, and apoptosis. Associations between genes in the DUSP, ERK1/2, JNK, and p38 MAPK-signaling pathways and dietary factors associated with growth factors, inflammation, and oxidative stress and risk of colon and rectal cancer were evaluated. Data include colon cases (n=1555) and controls (n=1956) and rectal cases (n=754) and controls (n=959). Statistically significant interactions were observed for the MAPK-signaling pathways after adjustment for multiple comparisons. DUSP genes interacted with carbohydrates, mutagen index, calories, calcium, vitamin D, lycopene, dietary fats, folic acid, and selenium. MAPK1, MAPK3, MAPK1 and RAF1 within the ERK1/2 MAPK-signaling pathway interacted with dietary fats and cruciferous vegetables. Within the JNK MAPK-signaling pathway, interactions between MAP3K7 and protein, vitamin C, iron, folic acid, carbohydrates, and cruciferous vegetables; MAP3K10 and folic acid; MAP3K9 and lutein/zeaxanthin; MAPK8 and calcium; MAP3K3 and calcium and lutein; MAP3K1 and cruciferous vegetables. Interaction within the p38-signaling pathway included: MAPK14 with calories, carbohydrates saturated fat, selenium, vitamin C; MAP3K2 and carbohydrates, and folic acid. These data suggest that dietary factors involved in inflammation and oxidative stress interact with MAPK-signaling genes to alter risk of colorectal cancer. PMID:23859041

  17. Statistical characterization of real-world illumination.

    PubMed

    Dror, Ron O; Willsky, Alan S; Adelson, Edward H

    2004-09-28

    Although studies of vision and graphics often assume simple illumination models, real-world illumination is highly complex, with reflected light incident on a surface from almost every direction. One can capture the illumination from every direction at one point photographically using a spherical illumination map. This work illustrates, through analysis of photographically acquired, high dynamic range illumination maps, that real-world illumination possesses a high degree of statistical regularity. The marginal and joint wavelet coefficient distributions and harmonic spectra of illumination maps resemble those documented in the natural image statistics literature. However, illumination maps differ from typical photographs in that illumination maps are statistically nonstationary and may contain localized light sources that dominate their power spectra. Our work provides a foundation for statistical models of real-world illumination, thereby facilitating the understanding of human material perception, the design of robust computer vision systems, and the rendering of realistic computer graphics imagery. PMID:15493972

  18. Pseudomonas aeruginosa pyocyanin activates NRF2-ARE-mediated transcriptional response via the ROS-EGFR-PI3K-AKT/MEK-ERK MAP kinase signaling in pulmonary epithelial cells.

    PubMed

    Xu, Ying; Duan, Chaohui; Kuang, Zhizhou; Hao, Yonghua; Jeffries, Jayme L; Lau, Gee W

    2013-01-01

    The redox-active pyocyanin (PCN) secreted by the respiratory pathogen Pseudomonas aeruginosa generates reactive oxygen species (ROS) and causes oxidative stress to pulmonary epithelial cells. Nuclear factor (erythroid-derived 2)-like 2 (NRF2) confers protection against ROS-mediated cell death by inducing the expression of detoxifying enzymes and proteins via its binding to the cis-acting antioxidant response element (ARE). However, a clear relationship between NRF2 and PCN-mediated oxidative stress has not been established experimentally. In this study, we investigated the induction of NRF2-ARE response by PCN in the pulmonary epithelial cells. We analyzed the effect of PCN on NRF2 expression and nuclear translocation in cultured human airway epithelial cells, and in a mouse model of chronic PCN exposure. NRF2-dependent transcription of antioxidative enzymes was also assessed. Furthermore, we used inhibitors to examine the involvement of EGFR and its downstream signaling components that mediate NRF2-ARE-activation in response to PCN. PCN enhances the nuclear NRF2 accumulation and activates the transcription of ARE-mediated antioxidant genes. Furthermore, PCN activates NRF2 by inducing the EGFR-phosphoinositide-3-kinase (PI3K) signaling pathway and its main downstream effectors, AKT and MEK1/2-ERK1/2 MAP kinases. Inhibition of the EGFR-PI3K signaling markedly attenuates PCN-stimulated NRF2 accumulation in the nucleus. We demonstrate for the first time that PCN-mediated oxidative stress activates the EGFR-PI3K-AKT/MEK1/2-ERK1/2 MAP kinase signaling pathway, leading to nuclear NRF2 translocation and ARE responsiveness in pulmonary epithelial cells.

  19. [Statistical materials].

    PubMed

    1986-01-01

    Official population data for the USSR are presented for 1985 and 1986. Part 1 (pp. 65-72) contains data on capitals of union republics and cities with over one million inhabitants, including population estimates for 1986 and vital statistics for 1985. Part 2 (p. 72) presents population estimates by sex and union republic, 1986. Part 3 (pp. 73-6) presents data on population growth, including birth, death, and natural increase rates, 1984-1985; seasonal distribution of births and deaths; birth order; age-specific birth rates in urban and rural areas and by union republic; marriages; age at marriage; and divorces. PMID:12178831

  20. The effects of cardamonin on lipopolysaccharide-induced inflammatory protein production and MAP kinase and NFκB signalling pathways in monocytes/macrophages

    PubMed Central

    Hatziieremia, S; Gray, A I; Ferro, V A; Paul, A; Plevin, R

    2006-01-01

    Background and purpose: In this study we examined the effect of the natural product cardamonin, upon lipopolysaccharide (LPS)-induced inflammatory gene expression in order to attempt to pinpoint the mechanism of action. Experimental approaches: Cardamonin was isolated from the Greek plant A. absinthium L. Its effects were assessed on LPS-induced nitrite release and iNOS and COX-2 protein expression in two macrophage cell lines. Western blotting was used to investigate its effects on phosphorylation of the mitogen activated protein (MAP) kinases, ERK, JNK and p38 MAP kinase, and activation of the NFκB pathway, at the level of IκBα degradation and phosphorylation of NFκB. Also its effects on NFκB and GAS/GAF-DNA binding were assessed by EMSA. Key results: Cardamonin concentration-dependently inhibited both NO release and iNOS expression but had no effect on COX-2 expression. It did not affect phosphorylation of the MAP kinases, degradation of IκBα or phosphorylation of NFκB. However, it inhibited NFκB DNA-binding in both LPS-stimulated cells and nuclear extracts of the cells (in vitro). It also inhibited IFNγ-stimulated iNOS induction and GAS/GAF-DNA binding. Conclusions and Implications: These results show that the inhibitory effect of cardamonin on LPS-induced iNOS induction is not mediated via effects on the initial activation of the NFκB or MAP kinase pathways but is due to a direct effect on transcription factor binding to DNA. However, although some selectivity in cardamonin's action is implicated by its inability to affect COX-2 expression, its exact mechanism(s) of action has yet to be identified. PMID:16894344

  1. Acquisition of contextual discrimination involves the appearance of a RAS-GRF1/p38 mitogen-activated protein (MAP) kinase-mediated signaling pathway that promotes long term potentiation (LTP).

    PubMed

    Jin, Shan-Xue; Arai, Junko; Tian, Xuejun; Kumar-Singh, Rajendra; Feig, Larry A

    2013-07-26

    RAS-GRF1 is a guanine nucleotide exchange factor with the ability to activate RAS and RAC GTPases in response to elevated calcium levels. We previously showed that beginning at 1 month of age, RAS-GRF1 mediates NMDA-type glutamate receptor (NMDAR)-induction of long term depression in the CA1 region of the hippocampus of mice. Here we show that beginning at 2 months of age, when mice first acquire the ability to discriminate between closely related contexts, RAS-GRF1 begins to contribute to the induction of long term potentiation (LTP) in the CA1 hippocampus by mediating the action of calcium-permeable, AMPA-type glutamate receptors (CP-AMPARs). Surprisingly, LTP induction by CP-AMPARs through RAS-GRF1 occurs via activation of p38 MAP kinase rather than ERK MAP kinase, which has more frequently been linked to LTP. Moreover, contextual discrimination is blocked by knockdown of Ras-Grf1 expression specifically in the CA1 hippocampus, infusion of a p38 MAP kinase inhibitor into the CA1 hippocampus, or the injection of an inhibitor of CP-AMPARs. These findings implicate the CA1 hippocampus in the developmentally dependent capacity to distinguish closely related contexts through the appearance of a novel LTP-supporting signaling pathway.

  2. Statistical theory of Internet exploration

    NASA Astrophysics Data System (ADS)

    Dall'Asta, Luca; Alvarez-Hamelin, Ignacio; Barrat, Alain; Vázquez, Alexei; Vespignani, Alessandro

    2005-03-01

    The general methodology used to construct Internet maps consists in merging all the discovered paths obtained by sending data packets from a set of active computers to a set of destination hosts, obtaining a graphlike representation of the network. This technique, sometimes referred to as Internet tomography, spurs the issue concerning the statistical reliability of such empirical maps. We tackle this problem by modeling the network sampling process on synthetic graphs and by using a mean-field approximation to obtain expressions for the probability of edge and vertex detection in the sampled graph. This allows a general understanding of the origin of possible sampling biases. In particular, we find a direct dependence of the map statistical accuracy upon the topological properties (in particular, the betweenness centrality property) of the underlying network. In this framework, it appears that statistically heterogeneous network topologies are captured better than the homogeneous ones during the mapping process. Finally, the analytical discussion is complemented with a thorough numerical investigation of simulated mapping strategies in network models with varying topological properties.

  3. The NO-cGMP-PKG Signaling Pathway Regulates Synaptic Plasticity and Fear Memory Consolidation in the Lateral Amygdala via Activation of ERK/MAP Kinase

    ERIC Educational Resources Information Center

    Ota, Kristie T.; Pierre, Vicki J.; Ploski, Jonathan E.; Queen, Kaila; Schafe, Glenn E.

    2008-01-01

    Recent studies have shown that nitric oxide (NO) signaling plays a crucial role in memory consolidation of Pavlovian fear conditioning and in synaptic plasticity in the lateral amygdala (LA). In the present experiments, we examined the role of the cGMP-dependent protein kinase (PKG), a downstream effector of NO, in fear memory consolidation and…

  4. Biochemical and pharmacological assessment of MAP-kinase signaling along pain pathways in experimental rodent models: a potential tool for the discovery of novel antinociceptive therapeutics.

    PubMed

    Edelmayer, Rebecca M; Brederson, Jill-Desiree; Jarvis, Michael F; Bitner, Robert S

    2014-02-01

    Injury to the peripheral or central nervous system can induce changes within the nervous tissues that promote a state of sensitization that may underlie conditions of pathological chronic pain. A key biochemical event in the initiation and maintenance of peripheral and central neuronal sensitization associated with chronic pain is the phosphorylation and subsequent activation of mitogen-activated protein kinases (MAPKs) and immediate early gene transcription factors, in particular cAMP-response element binding protein (CREB). In this commentary we review the preclinical data that describe anatomical and mechanistic aspects of nociceptive-induced signaling along nociceptive pathways including peripheral cutaneous axons, the dorsal root ganglia, spinal cord dorsal horn and cerebral cortex. In addition to the regional manifestation of nociceptive signaling, investigations have attempted to elucidate the cellular origin of biochemical nociceptive processing in which communication, i.e. cross-talk between neurons and glia is viewed as an essential component of pathogenic pain development. Here, we outline a research strategy by which nociceptive-induced cellular signaling in experimental pain models, specifically MAPK and CREB phosphorylation can be utilized to provide mechanistic insight into drug-target interaction along the nociceptive pathways. We describe a series of studies using nociceptive inflammatory and neuropathic pain models to investigate the effects of known pain therapeutics on nociceptive-induced biochemical signaling and present this as a complementary research strategy for assessing antinociceptive activity useful in the preclinical development of novel pain therapeutics.

  5. Planetary maps

    USGS Publications Warehouse

    ,

    1992-01-01

    An important goal of the USGS planetary mapping program is to systematically map the geology of the Moon, Mars, Venus, and Mercury, and the satellites of the outer planets. These geologic maps are published in the USGS Miscellaneous Investigations (I) Series. Planetary maps on sale at the USGS include shaded-relief maps, topographic maps, geologic maps, and controlled photomosaics. Controlled photomosaics are assembled from two or more photographs or images using a network of points of known latitude and longitude. The images used for most of these planetary maps are electronic images, obtained from orbiting television cameras, various optical-mechanical systems. Photographic film was only used to map Earth's Moon.

  6. The NO-cGMP-PKG signaling pathway regulates synaptic plasticity and fear memory consolidation in the lateral amygdala via activation of ERK/MAP kinase.

    PubMed

    Ota, Kristie T; Pierre, Vicki J; Ploski, Jonathan E; Queen, Kaila; Schafe, Glenn E

    2008-10-01

    Recent studies have shown that nitric oxide (NO) signaling plays a crucial role in memory consolidation of Pavlovian fear conditioning and in synaptic plasticity in the lateral amygdala (LA). In the present experiments, we examined the role of the cGMP-dependent protein kinase (PKG), a downstream effector of NO, in fear memory consolidation and long-term potentiation (LTP) at thalamic and cortical input pathways to the LA. In behavioral experiments, rats given intra-LA infusions of either the PKG inhibitor Rp-8-Br-PET-cGMPS or the PKG activator 8-Br-cGMP exhibited dose-dependent impairments or enhancements of fear memory consolidation, respectively. In slice electrophysiology experiments, bath application of Rp-8-Br-PET-cGMPS or the guanylyl cyclase inhibitor LY83583 impaired LTP at thalamic, but not cortical inputs to the LA, while bath application of 8-Br-cGMP or the guanylyl cyclase activator YC-1 resulted in enhanced LTP at thalamic inputs to the LA. Interestingly, YC-1-induced enhancement of LTP in the LA was reversed by concurrent application of the MEK inhibitor U0126, suggesting that the NO-cGMP-PKG signaling pathway may promote synaptic plasticity and fear memory formation in the LA, in part by activating the ERK/MAPK signaling cascade. As a test of this hypothesis, we next showed that rats given intra-LA infusion of the PKG inhibitor Rp-8-Br-PET-cGMPS or the PKG activator 8-Br-cGMP exhibit impaired or enhanced activation, respectively, of ERK/MAPK in the LA after fear conditioning. Collectively, our findings suggest that an NO-cGMP-PKG-dependent form of synaptic plasticity at thalamic input synapses to the LA may underlie memory consolidation of Pavlovian fear conditioning, in part, via activation of the ERK/MAPK signaling cascade.

  7. Fibroblast growth factor 23 regulates renal 1,25-dihydroxyvitamin D and phosphate metabolism via the MAP kinase signaling pathway in Hyp mice.

    PubMed

    Ranch, Daniel; Zhang, Martin Yh; Portale, Anthony A; Perwad, Farzana

    2011-08-01

    In X-linked hypophosphatemia (XLH) and in its murine homologue, the Hyp mouse, increased circulating concentrations of fibroblast growth factor 23 (FGF-23) are critical to the pathogenesis of disordered metabolism of phosphate (P(i)) and 1,25-dihydroxyvitamin D [1,25(OH)(2)D]. In this study, we hypothesized that in Hyp mice, FGF-23-mediated suppression of renal 1,25(OH)(2)D production and P(i) reabsorption depends on activation of mitogen-activated protein kinase (MAPK) signaling. Wild-type and Hyp mice were administered either vehicle or the MEK inhibitor PD0325901 (12.5 mg/kg) orally daily for 4 days. At baseline, the renal abundance of early growth response 1 (egr1) mRNA was approximately 2-fold greater in Hyp mice than in wild-type mice. Treatment with PD0325901 greatly suppressed egr1 mRNA abundance in both wild-type and Hyp mice. In Hyp mice, PD0325901 induced an 8-fold increase in renal 1α-hydroxylase mRNA expression and a 4-fold increase in serum 1,25(OH)(2)D concentrations compared with vehicle-treated Hyp mice. Serum P(i) levels in Hyp mice increased significantly after treatment with PD0325901, and the increase was associated with increased renal Npt2a mRNA abundance and brush-border membrane Npt2a protein expression. These findings provide evidence that in Hyp mice, MAPK signaling is constitutively activated in the kidney and support the hypothesis that the FGF-23-mediated suppression of renal 1,25(OH)(2)D production and P(i) reabsorption depends on activation of MAPK signaling via MEK/ERK1/2. These findings demonstrate the physiologic importance of MAPK signaling in the actions of FGF-23 in regulating renal 1,25(OH)(2)D and P(i) metabolism.

  8. Fibroblast Growth Factor 23 Regulates Renal 1,25-Dihydroxyvitamin D and Phosphate Metabolism via the MAP Kinase Signaling Pathway in Hyp Mice

    PubMed Central

    Ranch, Daniel; Zhang, Martin YH; Portale, Anthony A; Perwad, Farzana

    2015-01-01

    In X-linked hypophosphatemia (XLH) and in its murine homologue, the Hyp mouse, increased circulating concentrations of fibroblast growth factor 23 (FGF-23) are critical to the pathogenesis of disordered metabolism of phosphate (Pi) and 1,25-dihydroxyvitamin D [1,25(OH)2D]. In this study, we hypothesized that in Hyp mice, FGF-23-mediated suppression of renal 1,25(OH)2D production and Pi reabsorption depends on activation of mitogen-activated protein kinase (MAPK) signaling. Wild-type and Hyp mice were administered either vehicle or the MEK inhibitor PD0325901 (12.5 mg/kg) orally daily for 4 days. At baseline, the renal abundance of early growth response 1 (egr1) mRNA was approximately 2-fold greater in Hyp mice than in wild-type mice. Treatment with PD0325901 greatly suppressed egr1 mRNA abundance in both wild-type and Hyp mice. In Hyp mice, PD0325901 induced an 8-fold increase in renal 1α-hydroxylase mRNA expression and a 4-fold increase in serum 1,25(OH)2D concentrations compared with vehicle-treated Hyp mice. Serum Pi levels in Hyp mice increased significantly after treatment with PD0325901, and the increase was associated with increased renal Npt2a mRNA abundance and brush-border membrane Npt2a protein expression. These findings provide evidence that in Hyp mice, MAPK signaling is constitutively activated in the kidney and support the hypothesis that the FGF-23-mediated suppression of renal 1,25(OH)2D production and Pi reabsorption depends on activation of MAPK signaling via MEK/ERK1/2. These findings demonstrate the physiologic importance of MAPK signaling in the actions of FGF-23 in regulating renal 1,25(OH)2D and Pi metabolism. PMID:21472778

  9. A conserved docking site in MEKs mediates high-affinity binding to MAP kinases and cooperates with a scaffold protein to enhance signal transmission.

    PubMed

    Bardwell, A J; Flatauer, L J; Matsukuma, K; Thorner, J; Bardwell, L

    2001-03-30

    The recognition of mitogen-activated protein kinases (MAPKs) by their upstream activators, MAPK/ERK kinases (MEKs), is crucial for the effective and accurate transmission of many signals. We demonstrated previously that the yeast MAPKs Kss1 and Fus3 bind with high affinity to the N terminus of the MEK Ste7, and proposed that a conserved motif in Ste7, the MAPK-docking site, mediates this interaction. Here we show that the corresponding sequences in human MEK1 and MEK2 are necessary and sufficient for the direct binding of the MAPKs ERK1 and ERK2. Mutations in MEK1, MEK2, or Ste7 that altered conserved residues in the docking site diminished binding of the cognate MAPKs. Furthermore, short peptides corresponding to the docking sites in these MEKs inhibited MEK1-mediated phosphorylation of ERK2 in vitro. In yeast cells, docking-defective alleles of Ste7 were modestly compromised in their ability to transmit the mating pheromone signal. This deficiency was dramatically enhanced when the ability of the Ste5 scaffold protein to associate with components of the MAPK cascade was also compromised. Thus, both the MEK-MAPK docking interaction and binding to the Ste5 scaffold make mutually reinforcing contributions to the efficiency of signaling by this MAPK cascade in vivo. PMID:11134045

  10. PfIRR Interacts with HrIGF-I and Activates the MAP-kinase and PI3-kinase Signaling Pathways to Regulate Glycogen Metabolism in Pinctada fucata

    PubMed Central

    Shi, Yu; He, Mao-xian

    2016-01-01

    The insulin-induced mitogen-activated protein kinase (MAPK) and phosphatidylinositol 3-kinase (PI3K) pathways are major intracellular signaling modules and conserved among eukaryotes that are known to regulate diverse cellular processes. However, they have not been investigated in the mollusk species Pinctada fucata. Here, we demonstrate that insulin-related peptide receptor of P. fucata (pfIRR) interacts with human recombinant insulin-like growth factor I (hrIGF-I), and stimulates the MAPK and PI3K signaling pathways in P. fucata oocytes. We also show that inhibition of pfIRR by the inhibitor PQ401 significantly attenuates the basal and hrIGF-I-induced phosphorylation of MAPK and PI3K/Akt at amino acid residues threonine 308 and serine 473. Furthermore, our experiments show that there is cross-talk between the MAPK and PI3K/Akt pathways, in which MAPK kinase positively regulates the PI3K pathway, and PI3K positively regulates the MAPK cascade. Intramuscular injection of hrIGF-I stimulates the PI3K and MAPK pathways to increase the expression of pfirr, protein phosphatase 1, glucokinase, and the phosphorylation of glycogen synthase, decreases the mRNA expression of glycogen synthase kinase-3 beta, decreases glucose levels in hemocytes, and increases glycogen levels in digestive glands. These results suggest that the MAPK and PI3K pathways in P. fucata transmit the hrIGF-I signal to regulate glycogen metabolism. PMID:26911653

  11. PfIRR Interacts with HrIGF-I and Activates the MAP-kinase and PI3-kinase Signaling Pathways to Regulate Glycogen Metabolism in Pinctada fucata.

    PubMed

    Shi, Yu; He, Mao-xian

    2016-01-01

    The insulin-induced mitogen-activated protein kinase (MAPK) and phosphatidylinositol 3-kinase (PI3K) pathways are major intracellular signaling modules and conserved among eukaryotes that are known to regulate diverse cellular processes. However, they have not been investigated in the mollusk species Pinctada fucata. Here, we demonstrate that insulin-related peptide receptor of P. fucata (pfIRR) interacts with human recombinant insulin-like growth factor I (hrIGF-I), and stimulates the MAPK and PI3K signaling pathways in P. fucata oocytes. We also show that inhibition of pfIRR by the inhibitor PQ401 significantly attenuates the basal and hrIGF-I-induced phosphorylation of MAPK and PI3K/Akt at amino acid residues threonine 308 and serine 473. Furthermore, our experiments show that there is cross-talk between the MAPK and PI3K/Akt pathways, in which MAPK kinase positively regulates the PI3K pathway, and PI3K positively regulates the MAPK cascade. Intramuscular injection of hrIGF-I stimulates the PI3K and MAPK pathways to increase the expression of pfirr, protein phosphatase 1, glucokinase, and the phosphorylation of glycogen synthase, decreases the mRNA expression of glycogen synthase kinase-3 beta, decreases glucose levels in hemocytes, and increases glycogen levels in digestive glands. These results suggest that the MAPK and PI3K pathways in P. fucata transmit the hrIGF-I signal to regulate glycogen metabolism.

  12. ERK Signals: Scaffolding Scaffolds?

    PubMed Central

    Casar, Berta; Crespo, Piero

    2016-01-01

    ERK1/2 MAP Kinases become activated in response to multiple intra- and extra-cellular stimuli through a signaling module composed of sequential tiers of cytoplasmic kinases. Scaffold proteins regulate ERK signals by connecting the different components of the module into a multi-enzymatic complex by which signal amplitude and duration are fine-tuned, and also provide signal fidelity by isolating this complex from external interferences. In addition, scaffold proteins play a central role as spatial regulators of ERKs signals. In this respect, depending on the subcellular localization from which the activating signals emanate, defined scaffolds specify which substrates are amenable to be phosphorylated. Recent evidence has unveiled direct interactions among different scaffold protein species. These scaffold-scaffold macro-complexes could constitute an additional level of regulation for ERK signals and may serve as nodes for the integration of incoming signals and the subsequent diversification of the outgoing signals with respect to substrate engagement. PMID:27303664

  13. Map accuracy

    USGS Publications Warehouse

    ,

    1981-01-01

    An inaccurate map is not a reliable map. "X" may mark the spot where the treasure is buried, but unless the seeker can locate "X" in relation to known landmarks or positions, the map is not very useful.

  14. 22(R)-hydroxycholesterol induces HuR-dependent MAP kinase phosphatase-1 expression via mGluR5-mediated Ca(2+)/PKCα signaling.

    PubMed

    Kim, Hyunmi; Woo, Joo Hong; Lee, Jee Hoon; Joe, Eun-Hye; Jou, Ilo

    2016-08-01

    MAP kinase phosphatase (MKP)-1 plays a pivotal role in controlling MAP kinase (MAPK)-dependent (patho) physiological processes. Although MKP-1 gene expression is tightly regulated at multiple levels, the underlying mechanistic details remain largely unknown. In this study, we demonstrate that MKP-1 expression is regulated at the post-transcriptional level by 22(R)-hydroxycholesterol [22(R)-HC] through a novel mechanism. 22(R)-HC induces Hu antigen R (HuR) phosphorylation, cytoplasmic translocation and binding to MKP-1 mRNA, resulting in stabilization of MKP-1 mRNA. The resulting increase in MKP-1 leads to suppression of JNK-mediated inflammatory responses in brain astrocytes. We further demonstrate that 22(R)-HC-induced phosphorylation of nuclear HuR is mediated by PKCα, which is activated in the cytosol by increases in intracellular Ca(2+) levels mediated by the phospholipase C/inositol 1,4,5-triphosphate receptor (PLC/IP3R) pathway and translocates from cytoplasm to nucleus. In addition, pharmacological interventions reveal that metabotropic glutamate receptor5 (mGluR5) is responsible for the increases in intracellular Ca(2+) that underlie these actions of 22(R)-HC. Collectively, our findings identify a novel anti-inflammatory mechanism of 22(R)-HC, which acts through PKCα-mediated cytoplasmic shuttling of HuR to post-transcriptionally regulate MKP-1 expression. These findings provide an experimental basis for the development of a RNA-targeted therapeutic agent to control MAPK-dependent inflammatory responses.

  15. Two-dimensional proteome reference map of Prototheca zopfii revealed reduced metabolism and enhanced signal transduction as adaptation to an infectious life style.

    PubMed

    Murugaiyan, Jayaseelan; Weise, Christoph; von Bergen, Martin; Roesler, Uwe

    2013-09-01

    Biochemical, serological, and genetic analyses have identified two genotypes of Prototheca zopfii, a unicellular microalga belonging to the family Chlorellaceae. The P. zopfii genotype 1, abundantly present in cow barns and environment, remains nonpathogenic, while P. zopfii genotype 2 has been isolated from cows with bovine mastitis. The present study was carried out to identify the protein expression level difference between the pathogenic and nonpathogenic strains of P. zopfii. A total of 782 protein spots were observed on the 2D fluorescence difference gel electrophoresis (2D DIGE) gels among which 63 and 44 proteins were identified to be overexpressed in genotypes 1 and 2, respectively. The limited number of protein entries specific for Prototheca in public repositories resulted mainly in the identification of proteins described in other algae, microorganisms, or plants. Gene ontology (GO) analysis indicated reduced carbohydrate metabolism in genotype 1, while genotype 2 displayed enhanced DNA binding, kinase activity, and signal transduction. These effects point to metabolic and signaling adaptations in the pathogenic strain and provide insights into the evolution of otherwise highly similar strains. All MS data have been deposited in the ProteomeXchange with identifier PXD000126. PMID:23852777

  16. Mycosporine-Like Amino Acids Promote Wound Healing through Focal Adhesion Kinase (FAK) and Mitogen-Activated Protein Kinases (MAP Kinases) Signaling Pathway in Keratinocytes.

    PubMed

    Choi, Yun-Hee; Yang, Dong Joo; Kulkarni, Atul; Moh, Sang Hyun; Kim, Ki Woo

    2015-11-26

    Mycosporine-like amino acids (MAAs) are secondary metabolites found in diverse marine, freshwater, and terrestrial organisms. Evidence suggests that MAAs have several beneficial effects on skin homeostasis such as protection against UV radiation and reactive oxygen species (ROS). In addition, MAAs are also involved in the modulation of skin fibroblasts proliferation. However, the regulatory function of MAAs on wound repair in human skin is not yet clearly elucidated. To investigate the roles of MAAs on the wound healing process in human keratinocytes, three MAAs, Shinorine (SH), Mycosporine-glycine (M-Gly), and Porphyra (P334) were purified from Chlamydomonas hedlyei and Porphyra yezoensis. We found that SH, M-Gly, and P334 have significant effects on the wound healing process in human keratinocytes and these effects were mediated by activation of focal adhesion kinases (FAK), extracellular signal-regulated kinases (ERK), and c-Jun N-terminal kinases (JNK). These results suggest that MAAs accelerate wound repair by activating the FAK-MAPK signaling pathways. This study also indicates that MAAs can act as a new wound healing agent and further suggests that MAAs might be a novel biomaterial for wound healing therapies.

  17. Mycosporine-Like Amino Acids Promote Wound Healing through Focal Adhesion Kinase (FAK) and Mitogen-Activated Protein Kinases (MAP Kinases) Signaling Pathway in Keratinocytes

    PubMed Central

    Choi, Yun-Hee; Yang, Dong Joo; Kulkarni, Atul; Moh, Sang Hyun; Kim, Ki Woo

    2015-01-01

    Mycosporine-like amino acids (MAAs) are secondary metabolites found in diverse marine, freshwater, and terrestrial organisms. Evidence suggests that MAAs have several beneficial effects on skin homeostasis such as protection against UV radiation and reactive oxygen species (ROS). In addition, MAAs are also involved in the modulation of skin fibroblasts proliferation. However, the regulatory function of MAAs on wound repair in human skin is not yet clearly elucidated. To investigate the roles of MAAs on the wound healing process in human keratinocytes, three MAAs, Shinorine (SH), Mycosporine-glycine (M-Gly), and Porphyra (P334) were purified from Chlamydomonas hedlyei and Porphyra yezoensis. We found that SH, M-Gly, and P334 have significant effects on the wound healing process in human keratinocytes and these effects were mediated by activation of focal adhesion kinases (FAK), extracellular signal-regulated kinases (ERK), and c-Jun N-terminal kinases (JNK). These results suggest that MAAs accelerate wound repair by activating the FAK-MAPK signaling pathways. This study also indicates that MAAs can act as a new wound healing agent and further suggests that MAAs might be a novel biomaterial for wound healing therapies. PMID:26703626

  18. MAP kinase and cAMP filamentation signaling pathways converge on the unusually large promoter of the yeast FLO11 gene.

    PubMed

    Rupp, S; Summers, E; Lo, H J; Madhani, H; Fink, G

    1999-03-01

    In Saccharomyces cerevisiae, two major signal transduction pathways, the Kss1 MAPK pathway and the cAMP-regulated pathway, are critical for the differentiation of round yeast form cells to multicellular, invasive pseudohyphae. Here we report that these parallel pathways converge on the promoter of a gene, FLO11, which encodes a cell surface protein required for pseudohyphal formation. The FLO11 promoter is unusually large, containing at least four upstream activation sequences (UASs) and nine repression elements which together span at least 2.8 kb. Several lines of evidence indicate that the MAPK and cAMP signals are received by distinct transcription factors and promoter elements. First, regulation via the MAPK pathway requires the transcription factors Ste12p/Tec1p, whereas cAMP-mediated activation requires a distinct factor, Flo8p. Secondly, mutations in either pathway block FLO11 transcription. Overexpression of STE12 can suppress the loss of FLO8, and overexpression of FLO8 can suppress the loss of STE12. Finally, multiple distinct promoter regions of the FLO11 promoter are required for its activation by either Flo8p or Ste12p/ Tec1p. Thus, like the promoters of the key developmental genes, HO and IME1, the FLO11 promoter is large and complex, endowing it with the ability to integrate multiple inputs. PMID:10064592

  19. Computing contingency statistics in parallel.

    SciTech Connect

    Bennett, Janine Camille; Thompson, David; Pebay, Philippe Pierre

    2010-09-01

    Statistical analysis is typically used to reduce the dimensionality of and infer meaning from data. A key challenge of any statistical analysis package aimed at large-scale, distributed data is to address the orthogonal issues of parallel scalability and numerical stability. Many statistical techniques, e.g., descriptive statistics or principal component analysis, are based on moments and co-moments and, using robust online update formulas, can be computed in an embarrassingly parallel manner, amenable to a map-reduce style implementation. In this paper we focus on contingency tables, through which numerous derived statistics such as joint and marginal probability, point-wise mutual information, information entropy, and {chi}{sup 2} independence statistics can be directly obtained. However, contingency tables can become large as data size increases, requiring a correspondingly large amount of communication between processors. This potential increase in communication prevents optimal parallel speedup and is the main difference with moment-based statistics where the amount of inter-processor communication is independent of data size. Here we present the design trade-offs which we made to implement the computation of contingency tables in parallel.We also study the parallel speedup and scalability properties of our open source implementation. In particular, we observe optimal speed-up and scalability when the contingency statistics are used in their appropriate context, namely, when the data input is not quasi-diffuse.

  20. A map describing the association between effective components of traditional Chinese medicine and signaling pathways in cancer cells in vitro and in vivo.

    PubMed

    Xia, Jufeng; Chen, Jialu; Zhang, Zhongmin; Song, Peipei; Tang, Wei; Kokudo, Norihiro

    2014-08-01

    Cancer is the second leading cause of death by disease in the world. Chemotherapy is one of three major therapeutic methods for cancer treatment, but cancer cells gradually evolve resistance to chemotherapeutic reagents. For centuries, traditional Chinese medicine (TCM) was used to fight against cancer. In recent years, a number of effective component mechanisms of TCM have been increasingly illuminated. As we know, chemical structures of reagents decide or affect their activities on target pathways. Thus, we classified some antitumor-related TCM components reported in the last five years into thirteen groups by their chemical structures, such as, alkaloids, diterpenoids, triterpenes, sesquiterpenes, anthraquinones, benzoquinones, flavonoids, berbamines, xanthones, saponins, steroids, polysaccharides, and glycosides. In various cancer cell lines, these constituents target dozens of signaling pathways in vitro and in vivo. Among these components, there are three sets: i) mainly apoptosis-related groups, such as, alkaloids, diterpenoids, anthraquinones, berbamines, and xanthones, target pathways like the mitochondrial pathway, NF-κB pathway, p53 pathway and so on; ii) mainly proliferation, invasion and metastasis-related groups, such as, triterpenes, sesquiterpenes, polysaccharides, and glycosides, target pathways like the mTOR pathway, β-catenin pathway, ERK pathway and so on; iii) both apoptosis and proliferation, invasion and metastasis-related groups, such as benzoquinones, flavonoids, saponins, and steroids, target the pathways in i) and ii) synchronously. These will provide association information between TCM components and signaling pathways to promote studies on mechanisms of effective constituents, target drug development, and combinational chemotherapy. TCM could be alternative medicine for cancer treatment in the future.

  1. Exploring maps

    USGS Publications Warehouse

    ,

    1993-01-01

    Exploring Maps is an interdisciplinary set of materials on mapping for grades 7-12. Students will learn basic mapmaking and map reading skills and will see how maps can answer fundamental geographic questions: "Where am I?" "What else is here?" "Where am I going?"

  2. Statistical Mechanics of Optimal Convex Inference in High Dimensions

    NASA Astrophysics Data System (ADS)

    Advani, Madhu; Ganguli, Surya

    2016-07-01

    A fundamental problem in modern high-dimensional data analysis involves efficiently inferring a set of P unknown model parameters governing the relationship between the inputs and outputs of N noisy measurements. Various methods have been proposed to regress the outputs against the inputs to recover the P parameters. What are fundamental limits on the accuracy of regression, given finite signal-to-noise ratios, limited measurements, prior information, and computational tractability requirements? How can we optimally combine prior information with measurements to achieve these limits? Classical statistics gives incisive answers to these questions as the measurement density α =(N /P )→∞ . However, these classical results are not relevant to modern high-dimensional inference problems, which instead occur at finite α . We employ replica theory to answer these questions for a class of inference algorithms, known in the statistics literature as M-estimators. These algorithms attempt to recover the P model parameters by solving an optimization problem involving minimizing the sum of a loss function that penalizes deviations between the data and model predictions, and a regularizer that leverages prior information about model parameters. Widely cherished algorithms like maximum likelihood (ML) and maximum-a posteriori (MAP) inference arise as special cases of M-estimators. Our analysis uncovers fundamental limits on the inference accuracy of a subclass of M-estimators corresponding to computationally tractable convex optimization problems. These limits generalize classical statistical theorems like the Cramer-Rao bound to the high-dimensional setting with prior information. We further discover the optimal M-estimator for log-concave signal and noise distributions; we demonstrate that it can achieve our high-dimensional limits on inference accuracy, while ML and MAP cannot. Intriguingly, in high dimensions, these optimal algorithms become computationally simpler than

  3. Rain-Mapping Radar

    NASA Technical Reports Server (NTRS)

    Im, K. E.; Li, F. K.; Wilson, W. J.; Rosing, D.

    1988-01-01

    Orbiting radar system measures rates of rainfall from 0.5 to 60 mm/h. Radar waves scattered and absorbed by rainfall to extents depending on wavelength, polarization, rate of rainfall, and distribution of sizes and shapes of raindrops. Backscattered radar signal as function of length of path through rain used to infer detailed information about rain. Accumulated radar return signals processed into global maps of monthly average rainfall for use in climatological studies.

  4. Extreme value statistics of weak lensing shear peak counts

    NASA Astrophysics Data System (ADS)

    Reischke, R.; Maturi, M.; Bartelmann, M.

    2016-02-01

    The statistics of peaks in weak gravitational lensing maps is a promising technique to constrain cosmological parameters in present and future surveys. Here we investigate its power when using general extreme value statistics which is very sensitive to the exponential tail of the halo mass function. To this end, we use an analytic method to quantify the number of weak lensing peaks caused by galaxy clusters, large-scale structures and observational noise. Doing so, we further improve the method in the regime of high signal-to-noise ratios dominated by non-linear structures by accounting for the embedding of those counts into the surrounding shear caused by large-scale structures. We derive the extreme value and order statistics for both overdensities (positive peaks) and underdensities (negative peaks) and provide an optimized criterion to split a wide field survey into subfields in order to sample the distribution of extreme values such that the expected objects causing the largest signals are mostly due to galaxy clusters. We find good agreement of our model predictions with a ray-tracing N-body simulation. For a Euclid-like survey, we find tight constraints on σ8 and Ωm with relative uncertainties of ˜10-3. In contrast, the equation of state parameter w0 can be constrained only with a 10 per cent level, and wa is out of reach even if we include redshift information.

  5. Statistical mechanics of nucleosomes

    NASA Astrophysics Data System (ADS)

    Chereji, Razvan V.

    Eukaryotic cells contain long DNA molecules (about two meters for a human cell) which are tightly packed inside the micrometric nuclei. Nucleosomes are the basic packaging unit of the DNA which allows this millionfold compactification. A longstanding puzzle is to understand the principles which allow cells to both organize their genomes into chromatin fibers in the crowded space of their nuclei, and also to keep the DNA accessible to many factors and enzymes. With the nucleosomes covering about three quarters of the DNA, their positions are essential because these influence which genes can be regulated by the transcription factors and which cannot. We study physical models which predict the genome-wide organization of the nucleosomes and also the relevant energies which dictate this organization. In the last five years, the study of chromatin knew many important advances. In particular, in the field of nucleosome positioning, new techniques of identifying nucleosomes and the competing DNA-binding factors appeared, as chemical mapping with hydroxyl radicals, ChIP-exo, among others, the resolution of the nucleosome maps increased by using paired-end sequencing, and the price of sequencing an entire genome decreased. We present a rigorous statistical mechanics model which is able to explain the recent experimental results by taking into account nucleosome unwrapping, competition between different DNA-binding proteins, and both the interaction between histones and DNA, and between neighboring histones. We show a series of predictions of our new model, all in agreement with the experimental observations.

  6. Inhibition of MAP kinase/NF-kB mediated signaling and attenuation of lipopolysaccharide induced severe sepsis by cerium oxide nanoparticles

    PubMed Central

    Selvaraj, Vellaisamy; Nepal, Niraj; Rogers, Steven; Manne, Nandini D.P.K.; Arvapalli, Ravikumar; Rice, Kevin M.; Asano, Shinichi; Fankhanel, Erin; Ma, Jane J.; Shokuhfar, Tolou; Maheshwari, Mani; Blough, Eric R.

    2015-01-01

    Sepsis is a life threatening disease that is associated with high mortality. Existing treatments have failed to improve survivability in septic patients. The purpose of this present study is to evaluate whether cerium oxide nanoparticles (CeO2NPs) can prevent lipopolysaccharide (LPS) induced severe sepsis mortality by preventing hepatic dysfunction in male Sprague Dawley rats. Administration of a single dose (0.5 mg/kg) of CeO2NPs intravenously to septic rats significantly improved survival rates and functioned to restore body temperature, respiratory rate and blood pressure towards baseline. Treatment-induced increases in animal survivability were associated with decreased hepatic damage along with reductions in serum cytokines/chemokines, and diminished inflammatory related signaling. Kupffer cells and macrophage cells exposed to CeO2NPs exhibited decreases in LPS-induced cytokine release (TNF-α, IL-1β, IL-6, HMGB1) which were associated with diminished cellular ROS, reduced levels of nitric oxide synthase (iNOS), cyclooxygenase 2 (COX-2), and decreased nuclear factor-kappa light chain enhancer of activated B cells (NF-kB) transcriptional activity. The findings of this study indicate that CeO2NPs may be useful as a therapeutic agent for sepsis. PMID:25968464

  7. FEM: Feature-enhanced map

    SciTech Connect

    Afonine, Pavel V.; Moriarty, Nigel W.; Mustyakimov, Marat; Sobolev, Oleg V.; Terwilliger, Thomas C.; Turk, Dusan; Urzhumtsev, Alexandre; Adams, Paul D.

    2015-02-26

    A method is presented that modifies a 2mFobs-DFmodelσA-weighted map such that the resulting map can strengthen a weak signal, if present, and can reduce model bias and noise. The method consists of first randomizing the starting map and filling in missing reflections using multiple methods. This is followed by restricting the map to regions with convincing density and the application of sharpening. The final map is then created by combining a series of histogram-equalized intermediate maps. In the test cases shown, the maps produced in this way are found to have increased interpretability and decreased model bias compared with the starting 2mFobs-DFmodelσA-weighted map.

  8. FEM: Feature-enhanced map

    DOE PAGES

    Afonine, Pavel V.; Moriarty, Nigel W.; Mustyakimov, Marat; Sobolev, Oleg V.; Terwilliger, Thomas C.; Turk, Dusan; Urzhumtsev, Alexandre; Adams, Paul D.

    2015-02-26

    A method is presented that modifies a 2mFobs-DFmodelσA-weighted map such that the resulting map can strengthen a weak signal, if present, and can reduce model bias and noise. The method consists of first randomizing the starting map and filling in missing reflections using multiple methods. This is followed by restricting the map to regions with convincing density and the application of sharpening. The final map is then created by combining a series of histogram-equalized intermediate maps. In the test cases shown, the maps produced in this way are found to have increased interpretability and decreased model bias compared with themore » starting 2mFobs-DFmodelσA-weighted map.« less

  9. FEM: feature-enhanced map

    PubMed Central

    Afonine, Pavel V.; Moriarty, Nigel W.; Mustyakimov, Marat; Sobolev, Oleg V.; Terwilliger, Thomas C.; Turk, Dusan; Urzhumtsev, Alexandre; Adams, Paul D.

    2015-01-01

    A method is presented that modifies a 2m F obs − D F model σA-weighted map such that the resulting map can strengthen a weak signal, if present, and can reduce model bias and noise. The method consists of first randomizing the starting map and filling in missing reflections using multiple methods. This is followed by restricting the map to regions with convincing density and the application of sharpening. The final map is then created by combining a series of histogram-equalized intermediate maps. In the test cases shown, the maps produced in this way are found to have increased interpretability and decreased model bias compared with the starting 2m F obs − D F model σA-weighted map. PMID:25760612

  10. Cosmetic Plastic Surgery Statistics

    MedlinePlus

    2014 Cosmetic Plastic Surgery Statistics Cosmetic Procedure Trends 2014 Plastic Surgery Statistics Report Please credit the AMERICAN SOCIETY OF PLASTIC SURGEONS when citing statistical data or using ...