Science.gov

Sample records for multitype branching processes

  1. Using multitype branching processes to quantify statistics of disease outbreaks in zoonotic epidemics

    NASA Astrophysics Data System (ADS)

    Singh, Sarabjeet; Schneider, David J.; Myers, Christopher R.

    2014-03-01

    Branching processes have served as a model for chemical reactions, biological growth processes, and contagion (of disease, information, or fads). Through this connection, these seemingly different physical processes share some common universalities that can be elucidated by analyzing the underlying branching process. In this work we focus on coupled branching processes as a model of infectious diseases spreading from one population to another. An exceedingly important example of such coupled outbreaks are zoonotic infections that spill over from animal populations to humans. We derive several statistical quantities characterizing the first spillover event from animals to humans, including the probability of spillover, the first passage time distribution for human infection, and disease prevalence in the animal population at spillover. Large stochastic fluctuations in those quantities can make inference of the state of the system at the time of spillover difficult. Focusing on outbreaks in the human population, we then characterize the critical threshold for a large outbreak, the distribution of outbreak sizes, and associated scaling laws. These all show a strong dependence on the basic reproduction number in the animal population and indicate the existence of a novel multicritical point with altered scaling behavior. The coupling of animal and human infection dynamics has crucial implications, most importantly allowing for the possibility of large human outbreaks even when human-to-human transmission is subcritical.

  2. Limit Probabilities in a Multi-Type Critical Age-Dependent Branching Process

    DTIC Science & Technology

    1977-03-07

    or = m . Assuming this to be an m-type critical age-dependent branching process, for k = (k sub 1,...,k sub m) an m- vector of non-negative integers, not all of which are zero, it is shown that as t approaches infinity, P(Z sub i (t) = k) approx. = c/t squared for some c > 0. Similarly, let N sub i (t) = sub i1 (N sub i1 (t)), N sub i2 (t),...,N sub im(t) ) denote the m-vector with entries N sub ij (t) = total progeny of type j born by t in the critical m-type process starting with a new cell of type i at t = 0. For k = (k sub 1,...,k sub m) an m-vector of non-negative

  3. A composite likelihood approach to the analysis of longitudinal clonal data on multitype cellular systems under an age-dependent branching process

    PubMed Central

    Chen, Rui; Hyrien, Ollivier; Noble, Mark; Mayer-Pröschel, Margot

    2011-01-01

    A recurrent statistical problem in cell biology is to draw inference about cell kinetics from observations collected at discrete time points. We investigate this problem when multiple cell clones are observed longitudinally over time. The theory of age-dependent branching processes provides an appealing framework for the quantitative analysis of such data. Likelihood inference being difficult in this context, we propose an alternative composite likelihood approach, where the estimation function is defined from the marginal or conditional distributions of the number of cells of each observable cell type. These distributions have generally no closed-form expressions but they can be approximated using simulations. We construct a bias-corrected version of the estimating function, which also offers computational advantages. Two algorithms are discussed to compute parameter estimates. Large sample properties of the estimator are presented. The performance of the proposed method in finite samples is investigated in simulation studies. An application to the analysis of the generation of oligodendrocytes from oligodendrocyte type-2 astrocyte progenitor cells cultured in vitro reveals the effect of neurothrophin-3 on these cells. Our work demonstrates also that the proposed approach outperforms the existing ones. PMID:20732974

  4. Branching processes in disease epidemics

    NASA Astrophysics Data System (ADS)

    Singh, Sarabjeet

    Branching processes have served as a model for chemical reactions, biological growth processes and contagion (of disease, information or fads). Through this connection, these seemingly different physical processes share some common universalities that can be elucidated by analyzing the underlying branching process. In this thesis, we focus on branching processes as a model for infectious diseases spreading between individuals belonging to different populations. The distinction between populations can arise from species separation (as in the case of diseases which jump across species) or spatial separation (as in the case of disease spreading between farms, cities, urban centers, etc). A prominent example of the former is zoonoses -- infectious diseases that spill from animals to humans -- whose specific examples include Nipah virus, monkeypox, HIV and avian influenza. A prominent example of the latter is infectious diseases of animals such as foot and mouth disease and bovine tuberculosis that spread between farms or cattle herds. Another example of the latter is infectious diseases of humans such as H1N1 that spread from one city to another through migration of infectious hosts. This thesis consists of three main chapters, an introduction and an appendix. The introduction gives a brief history of mathematics in modeling the spread of infectious diseases along with a detailed description of the most commonly used disease model -- the Susceptible-Infectious-Recovered (SIR) model. The introduction also describes how the stochastic formulation of the model reduces to a branching process in the limit of large population which is analyzed in detail. The second chapter describes a two species model of zoonoses with coupled SIR processes and proceeds into the calculation of statistics pertinent to cross species infection using multitype branching processes. The third chapter describes an SIR process driven by a Poisson process of infection spillovers. This is posed as a

  5. Using multitype branching processes to quantify statistics of disease outbreaks in zoonotic epidemics

    USDA-ARS?s Scientific Manuscript database

    Despite the enormous relevance of zoonotic infections to world-wide public health, and despite much effort in modeling individual zoonoses, a fundamental understanding of the disease dynamics and the nature of outbreaks emanating from such a complex system is still lacking. We introduce a simple sto...

  6. A BAYESIAN HIERARCHICAL SPATIAL POINT PROCESS MODEL FOR MULTI-TYPE NEUROIMAGING META-ANALYSIS.

    PubMed

    Kang, Jian; Nichols, Thomas E; Wager, Tor D; Johnson, Timothy D

    2014-09-01

    Neuroimaging meta-analysis is an important tool for finding consistent effects over studies that each usually have 20 or fewer subjects. Interest in meta-analysis in brain mapping is also driven by a recent focus on so-called "reverse inference": where as traditional "forward inference" identifies the regions of the brain involved in a task, a reverse inference identifies the cognitive processes that a task engages. Such reverse inferences, however, requires a set of meta-analysis, one for each possible cognitive domain. However, existing methods for neuroimaging meta-analysis have significant limitations. Commonly used methods for neuroimaging meta-analysis are not model based, do not provide interpretable parameter estimates, and only produce null hypothesis inferences; further, they are generally designed for a single group of studies and cannot produce reverse inferences. In this work we address these limitations by adopting a non-parametric Bayesian approach for meta analysis data from multiple classes or types of studies. In particular, foci from each type of study are modeled as a cluster process driven by a random intensity function that is modeled as a kernel convolution of a gamma random field. The type-specific gamma random fields are linked and modeled as a realization of a common gamma random field, shared by all types, that induces correlation between study types and mimics the behavior of a univariate mixed effects model. We illustrate our model on simulation studies and a meta analysis of five emotions from 219 studies and check model fit by a posterior predictive assessment. In addition, we implement reverse inference by using the model to predict study type from a newly presented study. We evaluate this predictive performance via leave-one-out cross validation that is efficiently implemented using importance sampling techniques.

  7. A BAYESIAN HIERARCHICAL SPATIAL POINT PROCESS MODEL FOR MULTI-TYPE NEUROIMAGING META-ANALYSIS

    PubMed Central

    Kang, Jian; Nichols, Thomas E.; Wager, Tor D.; Johnson, Timothy D.

    2014-01-01

    Neuroimaging meta-analysis is an important tool for finding consistent effects over studies that each usually have 20 or fewer subjects. Interest in meta-analysis in brain mapping is also driven by a recent focus on so-called “reverse inference”: where as traditional “forward inference” identifies the regions of the brain involved in a task, a reverse inference identifies the cognitive processes that a task engages. Such reverse inferences, however, requires a set of meta-analysis, one for each possible cognitive domain. However, existing methods for neuroimaging meta-analysis have significant limitations. Commonly used methods for neuroimaging meta-analysis are not model based, do not provide interpretable parameter estimates, and only produce null hypothesis inferences; further, they are generally designed for a single group of studies and cannot produce reverse inferences. In this work we address these limitations by adopting a non-parametric Bayesian approach for meta analysis data from multiple classes or types of studies. In particular, foci from each type of study are modeled as a cluster process driven by a random intensity function that is modeled as a kernel convolution of a gamma random field. The type-specific gamma random fields are linked and modeled as a realization of a common gamma random field, shared by all types, that induces correlation between study types and mimics the behavior of a univariate mixed effects model. We illustrate our model on simulation studies and a meta analysis of five emotions from 219 studies and check model fit by a posterior predictive assessment. In addition, we implement reverse inference by using the model to predict study type from a newly presented study. We evaluate this predictive performance via leave-one-out cross validation that is efficiently implemented using importance sampling techniques. PMID:25426185

  8. Stochastic model for supersymmetric particle branching process

    NASA Astrophysics Data System (ADS)

    Zhang, Yuanyuan; Chan, Aik Hui; Oh, Choo Hiap

    2017-01-01

    We develop a stochastic branching model to describe the jet evolution of supersymmetric (SUSY) particles. This model is a modified two-phase branching process, or more precisely, a two-phase simple birth process plus Poisson process. Both pure SUSY partons initiated jets and SUSY plus ordinary partons initiated jets scenarios are considered. The stochastic branching equations are established and the Multiplicity Distributions (MDs) are derived for these two scenarios. We also fit the distribution of the general case (SUSY plus ordinary partons initiated jets) with experimental data. The fitting shows the SUSY particles have not participated in branching at current collision energy yet.

  9. Efficient Transition Probability Computation for Continuous-Time Branching Processes via Compressed Sensing

    PubMed Central

    Xu, Jason; Minin, Vladimir N.

    2016-01-01

    Branching processes are a class of continuous-time Markov chains (CTMCs) with ubiquitous applications. A general difficulty in statistical inference under partially observed CTMC models arises in computing transition probabilities when the discrete state space is large or uncountable. Classical methods such as matrix exponentiation are infeasible for large or countably infinite state spaces, and sampling-based alternatives are computationally intensive, requiring integration over all possible hidden events. Recent work has successfully applied generating function techniques to computing transition probabilities for linear multi-type branching processes. While these techniques often require significantly fewer computations than matrix exponentiation, they also become prohibitive in applications with large populations. We propose a compressed sensing framework that significantly accelerates the generating function method, decreasing computational cost up to a logarithmic factor by only assuming the probability mass of transitions is sparse. We demonstrate accurate and efficient transition probability computations in branching process models for blood cell formation and evolution of self-replicating transposable elements in bacterial genomes. PMID:26949377

  10. Residence times of branching diffusion processes

    NASA Astrophysics Data System (ADS)

    Dumonteil, E.; Mazzolo, A.

    2016-07-01

    The residence time of a branching Brownian process is the amount of time that the mother particle and all its descendants spend inside a domain. Using the Feynman-Kac formalism, we derive the residence-time equation as well as the equations for its moments for a branching diffusion process with an arbitrary number of descendants. This general approach is illustrated with simple examples in free space and in confined geometries where explicit formulas for the moments are obtained within the long time limit. In particular, we study in detail the influence of the branching mechanism on those moments. The present approach can also be applied to investigate other additive functionals of branching Brownian process.

  11. An age-dependent branching process model for the analysis of CFSE-labeling experiments

    PubMed Central

    2010-01-01

    Background Over the past decade, flow cytometric CFSE-labeling experiments have gained considerable popularity among experimentalists, especially immunologists and hematologists, for studying the processes of cell proliferation and cell death. Several mathematical models have been presented in the literature to describe cell kinetics during these experiments. Results We propose a multi-type age-dependent branching process to model the temporal development of populations of cells subject to division and death during CFSE-labeling experiments. We discuss practical implementation of the proposed model; we investigate a competing risk version of the process; and we identify the classes of cellular dependencies that may influence the expectation of the process and those that do not. An application is presented where we study the proliferation of human CD8+ T lymphocytes using our model and a competing risk branching process. Conclusions The proposed model offers a widely applicable approach to the analysis of CFSE-labeling experiments. The model fitted very well our experimental data. It provided reasonable estimates of cell kinetics parameters as well as meaningful insights into the processes of cell division and cell death. In contrast, the competing risk branching process could not describe the kinetics of CD8+ T cells. This suggested that the decision of cell division or cell death may be made early in the cell cycle if not in preceding generations. Also, we show that analyses based on the proposed model are robust with respect to cross-sectional dependencies and to dependencies between fates of linearly filiated cells. Reviewers This article was reviewed by Marek Kimmel, Wai-Yuan Tan and Peter Olofsson. PMID:20569476

  12. Quasi- and pseudo-maximum likelihood estimators for discretely observed continuous-time Markov branching processes

    PubMed Central

    Chen, Rui; Hyrien, Ollivier

    2011-01-01

    This article deals with quasi- and pseudo-likelihood estimation in a class of continuous-time multi-type Markov branching processes observed at discrete points in time. “Conventional” and conditional estimation are discussed for both approaches. We compare their properties and identify situations where they lead to asymptotically equivalent estimators. Both approaches possess robustness properties, and coincide with maximum likelihood estimation in some cases. Quasi-likelihood functions involving only linear combinations of the data may be unable to estimate all model parameters. Remedial measures exist, including the resort either to non-linear functions of the data or to conditioning the moments on appropriate sigma-algebras. The method of pseudo-likelihood may also resolve this issue. We investigate the properties of these approaches in three examples: the pure birth process, the linear birth-and-death process, and a two-type process that generalizes the previous two examples. Simulations studies are conducted to evaluate performance in finite samples. PMID:21552356

  13. Evaluation of multitype mathematical models for CFSE-labeling experiment data.

    PubMed

    Miao, Hongyu; Jin, Xia; Perelson, Alan S; Wu, Hulin

    2012-02-01

    Carboxy-fluorescein diacetate succinimidyl ester (CFSE) labeling is an important experimental tool for measuring cell responses to extracellular signals in biomedical research. However, changes of the cell cycle (e.g., time to division) corresponding to different stimulations cannot be directly characterized from data collected in CFSE-labeling experiments. A number of independent studies have developed mathematical models as well as parameter estimation methods to better understand cell cycle kinetics based on CFSE data. However, when applying different models to the same data set, notable discrepancies in parameter estimates based on different models has become an issue of great concern. It is therefore important to compare existing models and make recommendations for practical use. For this purpose, we derived the analytic form of an age-dependent multitype branching process model. We then compared the performance of different models, namely branching process, cyton, Smith-Martin, and a linear birth-death ordinary differential equation (ODE) model via simulation studies. For fairness of model comparison, simulated data sets were generated using an agent-based simulation tool which is independent of the four models that are compared. The simulation study results suggest that the branching process model significantly outperforms the other three models over a wide range of parameter values. This model was then employed to understand the proliferation pattern of CD4+ and CD8+ T cells under polyclonal stimulation.

  14. Agriculture and Food Processes Branch program summary document

    SciTech Connect

    Not Available

    1981-06-01

    The food industry, its energy consumption, and its energy conservation targets are discussed. Activities of the Agriculture and Food Processes Branch are described. Summaries of research, development, and demonstration programs of the Branch are given. The programs are categorized into the following: energy integrated farm systems; irrigation systems; crop drying systems; fertilizer; dairy and milk processing; meat processing; sugar processing; citrus processing; ethanol production; food processing efficiency systems; and food sterilization. Summaries are presented of 26 completed projects. (MCW)

  15. Dy163-Ho163 branching: an s-process barometer

    SciTech Connect

    Beer, H.; Walter, G.; Macklin, R.L.

    1984-01-01

    The neutron capture cross sections of Dy163 and Er164 have been measured to analyze the s-process branching at Dy163-Ho163. The reproduction of the s-process abundance of Er164 via this branching is sensitive to temperature kT, neutron density, and electron density n/sub e/. The calculations using information from other branchings on kT and the neutron density n/sub n/ give constraints for n/sub e/ at the site of the s-process.

  16. Dy163-Ho163 branching: An s-process barometer

    SciTech Connect

    Beer, H.; Walter, G.; Macklin, R.L.

    1985-01-15

    The neutron capture cross sections of Dy163 and Er164 have been measured to analyse the s-process branching at Dy163-Ho163. The reproduction of the s-process abundance of Er164 via this branching is sensitive to temperature kT, neutron density, and electron density n/sub e/. The calculations using information from other branchings on kT and the neutron density n/sub n/ give constraints for n/sub e/ at the site of the s-process.

  17. Finite-size scaling of survival probability in branching processes

    NASA Astrophysics Data System (ADS)

    Garcia-Millan, Rosalba; Font-Clos, Francesc; Corral, Álvaro

    2015-04-01

    Branching processes pervade many models in statistical physics. We investigate the survival probability of a Galton-Watson branching process after a finite number of generations. We derive analytically the existence of finite-size scaling for the survival probability as a function of the control parameter and the maximum number of generations, obtaining the critical exponents as well as the exact scaling function, which is G (y ) =2 y ey /(ey-1 ) , with y the rescaled distance to the critical point. Our findings are valid for any branching process of the Galton-Watson type, independently of the distribution of the number of offspring, provided its variance is finite. This proves the universal behavior of the finite-size effects in branching processes, including the universality of the metric factors. The direct relation to mean-field percolation is also discussed.

  18. The effect of polyglycerol sulfate branching on inflammatory processes.

    PubMed

    Paulus, Florian; Schulze, Ronny; Steinhilber, Dirk; Zieringer, Maximilian; Steinke, Ingo; Welker, Pia; Licha, Kai; Wedepohl, Stefanie; Dernedde, Jens; Haag, Rainer

    2014-05-01

    In this study, the extent to which the scaffold architecture of polyglycerol sulfates affects inflammatory processes and hemocompatibility is investigated. Competitive L-selectin binding assays, cellular uptake studies, and blood compatibility readouts are done to evaluate distinct biological properties. Fully glycerol based hyperbranched polyglycerol architectures are obtained by either homopolymerization of glycidol (60% branching) or a new copolymerization strategy of glycidol with ethoxyethyl glycidyl ether. Two polyglycerols with 24 and 42% degree of branching (DB) are synthesized by using different monomer feed ratios. A perfectly branched polyglycerol dendrimer is synthesized according to an iterative two-step protocol based on allylation of the alcohol and subsequent catalytic dihydroxylation. All the polyglycerol sulfates are synthesized with a comparable molecular weight and degree of sulfation. The DB make the different polymer conjugates perform different ways. The optimal DB is 60% in all biological assays.

  19. Superlinear scaling of offspring at criticality in branching processes

    NASA Astrophysics Data System (ADS)

    Saichev, A.; Sornette, D.

    2014-01-01

    For any branching process, we demonstrate that the typical total number rmp(ντ) of events triggered over all generations within any sufficiently large time window τ exhibits, at criticality, a superlinear dependence rmp(ντ)˜(ντ)γ (with γ >1) on the total number ντ of the immigrants arriving at the Poisson rate ν. In branching processes in which immigrants (or sources) are characterized by fertilities distributed according to an asymptotic power-law tail with tail exponent 1<γ ⩽2, the exponent of the superlinear law for rmp(ντ) is identical to the exponent γ of the distribution of fertilities. For γ >2 and for standard branching processes without power-law distribution of fertilities, rmp(ντ)˜(ντ)2. This scaling law replaces and tames the divergence ντ /(1-n) of the mean total number R¯t(τ) of events, as the branching ratio (defined as the average number of triggered events of first generation per source) tends to 1. The derivation uses the formalism of generating probability functions. The corresponding prediction is confirmed by numerical calculations, and an heuristic derivation enlightens its underlying mechanism. We also show that R¯t(τ) is always linear in ντ even at criticality (n =1). Our results thus illustrate the fundamental difference between the mean total number, which is controlled by a few extremely rare realizations, and the typical behavior represented by rmp(ντ).

  20. Agriculture and Food Processes Branch program summary document

    SciTech Connect

    1980-06-01

    The work of the Agriculture and Food Processes Branch within the US DOE's Office of Industrial Programs is discussed and reviewed. The Branch is responsible for assisting the food and agricultural sectors of the economy in increasing their energy efficiency by cost sharing with industry the development and demonstration of technologies industry by itself would not develop because of a greater than normal risk factor, but have significant energy conservation benefits. This task is made more difficult by the diversity of agriculture and the food industry. The focus of the program is now on the development and demonstration of energy conservation technology in high energy use industry sectors and agricultural functions (e.g., sugar processing, meat processing, irrigation, and crop drying, high energy use functions common to many sectors of the food industry (e.g., refrigeration, drying, and evaporation), and innovative concepts (e.g., energy integrated farm systems. Specific projects within the program are summarized. (LCL)

  1. Random Walks and Branching Processes in Correlated Gaussian Environment

    NASA Astrophysics Data System (ADS)

    Aurzada, Frank; Devulder, Alexis; Guillotin-Plantard, Nadine; Pène, Françoise

    2017-01-01

    We study persistence probabilities for random walks in correlated Gaussian random environment investigated by Oshanin et al. (Phys Rev Lett, 110:100602, 2013). From the persistence results, we can deduce properties of critical branching processes with offspring sizes geometrically distributed with correlated random parameters. More precisely, we obtain estimates on the tail distribution of its total population size, of its maximum population, and of its extinction time.

  2. Entity Network Prediction Using Multitype Topic Models

    NASA Astrophysics Data System (ADS)

    Shiozaki, Hitohiro; Eguchi, Koji; Ohkawa, Takenao

    Conveying information about who, what, when and where is a primary purpose of some genres of documents, typically news articles. Statistical models that capture dependencies between named entities and topics can play an important role. Although some relationships between who and where should be mentioned in such a document, no statistical topic models explicitly address in handling such information the textual interactions between a who-entity and a where-entity. This paper presents a statistical model that directly captures the dependencies between an arbitrary number of word types, such as who-entities, where-entities and topics, mentioned in each document. We show that this multitype topic model performs better at making predictions on entity networks, in which each vertex represents an entity and each edge weight represents how a pair of entities at the incident vertices is closely related, through our experiments on predictions of who-entities and links between them. We also demonstrate the scale-free property in the weighted networks of entities extracted from written mentions.

  3. Interacting Branching Process as a Simple Model of Innovation

    NASA Astrophysics Data System (ADS)

    Sood, Vishal; Mathieu, Myléne; Shreim, Amer; Grassberger, Peter; Paczuski, Maya

    2010-10-01

    We describe innovation in terms of a generalized branching process. Each new invention pairs with any existing one to produce a number of offspring, which is Poisson distributed with mean p. Existing inventions die with probability p/τ at each generation. In contrast with mean field results, no phase transition occurs; the chance for survival is finite for all p>0. For τ=∞, surviving processes exhibit a bottleneck before exploding superexponentially—a growth consistent with a law of accelerating returns. This behavior persists for finite τ. We analyze, in detail, the asymptotic behavior as p→0.

  4. Differential Correlates of Multi-Type Maltreatment among Urban Youth

    ERIC Educational Resources Information Center

    Arata, Catalina M.; Langhinrichsen-Rohling, Jennifer; Bowers, David; O'Brien, Natalie

    2007-01-01

    Objective: The aim of this study was to examine the differential effects of multi-types of maltreatment in an adolescent sample. Different combinations of maltreatment (emotional, sexual, physical, neglect) were examined in relation to both negative affect and externalizing symptoms in male and female youth. Method: One thousand four hundred…

  5. Differential Correlates of Multi-Type Maltreatment among Urban Youth

    ERIC Educational Resources Information Center

    Arata, Catalina M.; Langhinrichsen-Rohling, Jennifer; Bowers, David; O'Brien, Natalie

    2007-01-01

    Objective: The aim of this study was to examine the differential effects of multi-types of maltreatment in an adolescent sample. Different combinations of maltreatment (emotional, sexual, physical, neglect) were examined in relation to both negative affect and externalizing symptoms in male and female youth. Method: One thousand four hundred…

  6. Statistical distributions of earthquake numbers: consequence of branching process

    NASA Astrophysics Data System (ADS)

    Kagan, Yan Y.

    2010-03-01

    We discuss various statistical distributions of earthquake numbers. Previously, we derived several discrete distributions to describe earthquake numbers for the branching model of earthquake occurrence: these distributions are the Poisson, geometric, logarithmic and the negative binomial (NBD). The theoretical model is the `birth and immigration' population process. The first three distributions above can be considered special cases of the NBD. In particular, a point branching process along the magnitude (or log seismic moment) axis with independent events (immigrants) explains the magnitude/moment-frequency relation and the NBD of earthquake counts in large time/space windows, as well as the dependence of the NBD parameters on the magnitude threshold (magnitude of an earthquake catalogue completeness). We discuss applying these distributions, especially the NBD, to approximate event numbers in earthquake catalogues. There are many different representations of the NBD. Most can be traced either to the Pascal distribution or to the mixture of the Poisson distribution with the gamma law. We discuss advantages and drawbacks of both representations for statistical analysis of earthquake catalogues. We also consider applying the NBD to earthquake forecasts and describe the limits of the application for the given equations. In contrast to the one-parameter Poisson distribution so widely used to describe earthquake occurrence, the NBD has two parameters. The second parameter can be used to characterize clustering or overdispersion of a process. We determine the parameter values and their uncertainties for several local and global catalogues, and their subdivisions in various time intervals, magnitude thresholds, spatial windows, and tectonic categories. The theoretical model of how the clustering parameter depends on the corner (maximum) magnitude can be used to predict future earthquake number distribution in regions where very large earthquakes have not yet occurred.

  7. Effective dynamics in an asymmetric death-branching process

    NASA Astrophysics Data System (ADS)

    Torkaman, Pegah; Jafarpour, Farhad H.

    2017-08-01

    In this paper we study activity fluctuations in an asymmetric death-branching process in one-dimension. The model, which is a variant of the asymmetric Glauber model, has already been studied in Torkaman and Jafarpour (2015 J. Stat. Mech. P01007). It is known that in the low-activity region i.e. below the typical activity in the steady-state, the dynamical free energy of the system can be calculated exactly. However, the behavior of the system in the high-activity region is different and more interesting. The system undergoes a series of dynamical phase transitions. In present work we justify the hierarchy of dynamical phase transitions in terms of effective interactions in the system. It turns out that the effective interactions are long-range and that they can be described in terms of interactions between repelling shock fronts.

  8. Leading Process Branch Instability in Lis1+/− Nonradially Migrating Interneurons

    PubMed Central

    Gopal, Pallavi P.; Simonet, Jacqueline C.; Shapiro, William

    2010-01-01

    Mammalian forebrain development requires extensive migration, yet the mechanisms through which migrating neurons sense and respond to guidance cues are not well understood. Similar to the axon growth cone, the leading process and branches of neurons may guide migration, but the cytoskeletal events that regulate branching are unknown. We have previously shown that loss of microtubule-associated protein Lis1 reduces branching during migration compared with wild-type neurons. Using time-lapse imaging of Lis1+/− and Lis1+/+ cells migrating from medial ganglionic eminence explant cultures, we show that the branching defect is not due to a failure to initiate branches but a defect in the stabilization of new branches. The leading processes of Lis1+/− neurons have reduced expression of stabilized, acetylated microtubules compared with Lis1+/+ neurons. To determine whether Lis1 modulates branch stability through its role as the noncatalytic β regulatory subunit of platelet-activating factor (PAF) acetylhydrolase 1b, exogenous PAF was applied to wild-type cells. Excess PAF added to wild-type neurons phenocopies the branch instability observed in Lis1+/− neurons, and a PAF antagonist rescues leading process branching in Lis1+/− neurons. These data highlight a role for Lis1, acting through the PAF pathway, in leading process branching and microtubule stabilization. PMID:19861636

  9. Differential correlates of multi-type maltreatment among urban youth.

    PubMed

    Arata, Catalina M; Langhinrichsen-Rohling, Jennifer; Bowers, David; O'Brien, Natalie

    2007-04-01

    The aim of this study was to examine the differential effects of multi-types of maltreatment in an adolescent sample. Different combinations of maltreatment (emotional, sexual, physical, neglect) were examined in relation to both negative affect and externalizing symptoms in male and female youth. One thousand four hundred fifty-two middle and high school youth were recruited from urban schools and a mandated early warning truancy program. Youth completed an anonymous survey that included measures of child maltreatment, depression, suicide proneness, hopelessness, delinquency, hostility, substance use, and promiscuity. Respondents were categorized into groups of different combinations of maltreatment by their reports of sexual abuse, physical abuse, neglect (emotional and physical), and emotional abuse. Nearly two-thirds of boys and girls reported some form of maltreatment, and multi-type maltreatment was common (e.g., 13% reported experiencing both physical and sexual abuse and neglect). Individuals with maltreatment histories were more depressed (F=52.78, p<.0001), suicide prone (F=24.29, p<.001), and hopeless (F=32.07, p<.0001) than non-abused individuals. Maltreated adolescents were also more hostile (F=35.03, p<.0001), and they engaged in more delinquent behavior (F=26.76, p<.0001), promiscuity (F=8.54, p<.0001), and drug and alcohol use (F=9.61, p<.0001). Individuals experiencing multi-type maltreatment were the most symptomatic, particularly youth with histories of physical abuse, sexual abuse, and neglect. In general, gender differences in effects were not observed. The results highlight the importance of studying combined types of maltreatment, as well as understanding the particularly deleterious effects of neglect and emotional abuse. The results are generally consistent with an additive model of maltreatment effects.

  10. Limit of a nonpreferential attachment multitype network model

    NASA Astrophysics Data System (ADS)

    Shang, Yilun

    2017-02-01

    Here, we deal with a model of multitype network with nonpreferential attachment growth. The connection between two nodes depends asymmetrically on their types, reflecting the implication of time order in temporal networks. Based upon graph limit theory, we analytically determined the limit of the network model characterized by a kernel, in the sense that the number of copies of any fixed subgraph converges when network size tends to infinity. The results are confirmed by extensive simulations. Our work thus provides a theoretical framework for quantitatively understanding grown temporal complex networks as a whole.

  11. Health information multitype library reference referral networking: panacea for the '90s.

    PubMed

    Teplitskaia, H

    1998-07-01

    Librarians are exploring new approaches to information sharing to cope with a rapidly changing environment dominated by budget cuts, information explosion, and globalization of the economy, science, and culture. In 1990, the University of Illinois at Chicago Library of the Health Sciences (UIC LHS) initiated a pilot project aimed at establishing an effective balance between state-of-the-art information technology and traditional library methods and promoting cooperation among health information professionals by establishing the Health Information Referral Network (HIRN) in the state of Illinois. HIRN's background and development, Internet home page, and networking techniques reviewed in this paper are applicable to multitype libraries and information centers interested in improving information use and the referral process.

  12. Health information multitype library reference referral networking: panacea for the '90s.

    PubMed Central

    Teplitskaia, H

    1998-01-01

    Librarians are exploring new approaches to information sharing to cope with a rapidly changing environment dominated by budget cuts, information explosion, and globalization of the economy, science, and culture. In 1990, the University of Illinois at Chicago Library of the Health Sciences (UIC LHS) initiated a pilot project aimed at establishing an effective balance between state-of-the-art information technology and traditional library methods and promoting cooperation among health information professionals by establishing the Health Information Referral Network (HIRN) in the state of Illinois. HIRN's background and development, Internet home page, and networking techniques reviewed in this paper are applicable to multitype libraries and information centers interested in improving information use and the referral process. PMID:9681171

  13. Numerical analysis for finite-range multitype stochastic contact financial market dynamic systems.

    PubMed

    Yang, Ge; Wang, Jun; Fang, Wen

    2015-04-01

    In an attempt to reproduce and study the dynamics of financial markets, a random agent-based financial price model is developed and investigated by the finite-range multitype contact dynamic system, in which the interaction and dispersal of different types of investment attitudes in a stock market are imitated by viruses spreading. With different parameters of birth rates and finite-range, the normalized return series are simulated by Monte Carlo simulation method and numerical studied by power-law distribution analysis and autocorrelation analysis. To better understand the nonlinear dynamics of the return series, a q-order autocorrelation function and a multi-autocorrelation function are also defined in this work. The comparisons of statistical behaviors of return series from the agent-based model and the daily historical market returns of Shanghai Composite Index and Shenzhen Component Index indicate that the proposed model is a reasonable qualitative explanation for the price formation process of stock market systems.

  14. Numerical analysis for finite-range multitype stochastic contact financial market dynamic systems

    NASA Astrophysics Data System (ADS)

    Yang, Ge; Wang, Jun; Fang, Wen

    2015-04-01

    In an attempt to reproduce and study the dynamics of financial markets, a random agent-based financial price model is developed and investigated by the finite-range multitype contact dynamic system, in which the interaction and dispersal of different types of investment attitudes in a stock market are imitated by viruses spreading. With different parameters of birth rates and finite-range, the normalized return series are simulated by Monte Carlo simulation method and numerical studied by power-law distribution analysis and autocorrelation analysis. To better understand the nonlinear dynamics of the return series, a q-order autocorrelation function and a multi-autocorrelation function are also defined in this work. The comparisons of statistical behaviors of return series from the agent-based model and the daily historical market returns of Shanghai Composite Index and Shenzhen Component Index indicate that the proposed model is a reasonable qualitative explanation for the price formation process of stock market systems.

  15. Numerical analysis for finite-range multitype stochastic contact financial market dynamic systems

    SciTech Connect

    Yang, Ge; Wang, Jun; Fang, Wen

    2015-04-15

    In an attempt to reproduce and study the dynamics of financial markets, a random agent-based financial price model is developed and investigated by the finite-range multitype contact dynamic system, in which the interaction and dispersal of different types of investment attitudes in a stock market are imitated by viruses spreading. With different parameters of birth rates and finite-range, the normalized return series are simulated by Monte Carlo simulation method and numerical studied by power-law distribution analysis and autocorrelation analysis. To better understand the nonlinear dynamics of the return series, a q-order autocorrelation function and a multi-autocorrelation function are also defined in this work. The comparisons of statistical behaviors of return series from the agent-based model and the daily historical market returns of Shanghai Composite Index and Shenzhen Component Index indicate that the proposed model is a reasonable qualitative explanation for the price formation process of stock market systems.

  16. On trends and climatic effects of multi-type and cascading hazards in the Andes of Peru

    NASA Astrophysics Data System (ADS)

    Huggel, C.; Raissig, A.; Romero, G.; Rohrer, M.; Salzmann, N.; Díaz, A.; Acuña, D.

    2012-04-01

    the southern Peruvian Andes. Furthermore, sediment availability is an important driver in some cases, and temperature can have an effect in high mountain regions due water input from snow and ice melting. Particularly important in terms of hazard and risk assessment are geomorphological and hydrological processes that result in cascading multi-type hazards, with interactions between landslides, debris flows and floods. We conclude that it is not trivial to detect any significant and reliable trend in hydrometeorological disaster series in the Andes and caution should be applied when relating these disasters to any climatic change. Nevertheless, risk managements should consider short-term and long-term climate impacts, and poorly recognized cascading effects. Early warning systems, based on information such as generated in this study, should be designed and implemented as effective risk reduction measures.

  17. SDF1 Reduces Interneuron Leading Process Branching through Dual Regulation of Actin and Microtubules

    PubMed Central

    Lysko, Daniel E.; Putt, Mary

    2014-01-01

    Normal cerebral cortical function requires a highly ordered balance between projection neurons and interneurons. During development these two neuronal populations migrate from distinct progenitor zones to form the cerebral cortex, with interneurons originating in the more distant ganglionic eminences. Moreover, deficits in interneurons have been linked to a variety of neurodevelopmental disorders underscoring the importance of understanding interneuron development and function. We, and others, have identified SDF1 signaling as one important modulator of interneuron migration speed and leading process branching behavior in mice, although how SDF1 signaling impacts these behaviors remains unknown. We previously found SDF1 inhibited leading process branching while increasing the rate of migration. We have now mechanistically linked SDF1 modulation of leading process branching behavior to a dual regulation of both actin and microtubule organization. We find SDF1 consolidates actin at the leading process tip by de-repressing calpain protease and increasing proteolysis of branched-actin-supporting cortactin. Additionally, SDF1 stabilizes the microtubule array in the leading process through activation of the microtubule-associated protein doublecortin (DCX). DCX stabilizes the microtubule array by bundling microtubules within the leading process, reducing branching. These data provide mechanistic insight into the regulation of interneuron leading process dynamics during neuronal migration in mice and provides insight into how cortactin and DCX, a known human neuronal migration disorder gene, participate in this process. PMID:24695713

  18. SDF1 reduces interneuron leading process branching through dual regulation of actin and microtubules.

    PubMed

    Lysko, Daniel E; Putt, Mary; Golden, Jeffrey A

    2014-04-02

    Normal cerebral cortical function requires a highly ordered balance between projection neurons and interneurons. During development these two neuronal populations migrate from distinct progenitor zones to form the cerebral cortex, with interneurons originating in the more distant ganglionic eminences. Moreover, deficits in interneurons have been linked to a variety of neurodevelopmental disorders underscoring the importance of understanding interneuron development and function. We, and others, have identified SDF1 signaling as one important modulator of interneuron migration speed and leading process branching behavior in mice, although how SDF1 signaling impacts these behaviors remains unknown. We previously found SDF1 inhibited leading process branching while increasing the rate of migration. We have now mechanistically linked SDF1 modulation of leading process branching behavior to a dual regulation of both actin and microtubule organization. We find SDF1 consolidates actin at the leading process tip by de-repressing calpain protease and increasing proteolysis of branched-actin-supporting cortactin. Additionally, SDF1 stabilizes the microtubule array in the leading process through activation of the microtubule-associated protein doublecortin (DCX). DCX stabilizes the microtubule array by bundling microtubules within the leading process, reducing branching. These data provide mechanistic insight into the regulation of interneuron leading process dynamics during neuronal migration in mice and provides insight into how cortactin and DCX, a known human neuronal migration disorder gene, participate in this process.

  19. Experimental characterization of nonlinear processes of whistler branch waves

    NASA Astrophysics Data System (ADS)

    Tejero, E. M.; Crabtree, C.; Blackwell, D. D.; Amatucci, W. E.; Ganguli, G.; Rudakov, L.

    2016-05-01

    Experiments in the Space Physics Simulation Chamber at the Naval Research Laboratory isolated and characterized important nonlinear wave-wave and wave-particle interactions that can occur in the Earth's Van Allen radiation belts by launching predominantly electrostatic waves in the intermediate frequency range with wave normal angle greater than 85 ° and measuring the nonlinearly generated electromagnetic scattered waves. The scattered waves have a perpendicular wavelength that is nearly an order of magnitude larger than that of the pump wave. Calculations of scattering efficiency from experimental measurements demonstrate that the scattering efficiency is inversely proportional to the damping rate and trends towards unity as the damping rate approaches zero. Signatures of both wave-wave and wave-particle scatterings are also observed in the triggered emission process in which a launched wave resonant with a counter-propagating electron beam generates a large amplitude chirped whistler wave. The possibility of nonlinear scattering or three wave decay as a saturation mechanism for the triggered emission is suggested. The laboratory experiment has inspired the search for scattering signatures in the in situ data of chorus emission in the radiation belts.

  20. The Specific Features of design and process engineering in branch of industrial enterprise

    NASA Astrophysics Data System (ADS)

    Sosedko, V. V.; Yanishevskaya, A. G.

    2017-06-01

    Production output of industrial enterprise is organized in debugged working mechanisms at each stage of product’s life cycle from initial design documentation to product and finishing it with utilization. The topic of article is mathematical model of the system design and process engineering in branch of the industrial enterprise, statistical processing of estimated implementation results of developed mathematical model in branch, and demonstration of advantages at application at this enterprise. During the creation of model a data flow about driving of information, orders, details and modules in branch of enterprise groups of divisions were classified. Proceeding from the analysis of divisions activity, a data flow, details and documents the state graph of design and process engineering was constructed, transitions were described and coefficients are appropriated. To each condition of system of the constructed state graph the corresponding limiting state probabilities were defined, and also Kolmogorov’s equations are worked out. When integration of sets of equations of Kolmogorov the state probability of system activity the specified divisions and production as function of time in each instant is defined. On the basis of developed mathematical model of uniform system of designing and process engineering and manufacture, and a state graph by authors statistical processing the application of mathematical model results was carried out, and also advantage at application at this enterprise is shown. Researches on studying of loading services probability of branch and third-party contractors (the orders received from branch within a month) were conducted. The developed mathematical model of system design and process engineering and manufacture can be applied to definition of activity state probability of divisions and manufacture as function of time in each instant that will allow to keep account of loading of performance of work in branches of the enterprise.

  1. Comment on "Finite-size scaling of survival probability in branching processes"

    NASA Astrophysics Data System (ADS)

    Wei, Nanxin; Pruessner, Gunnar

    2016-12-01

    R. Garcia-Millan et al. [Phys. Rev. E 91, 042122 (2015), 10.1103/PhysRevE.91.042122] reported a universal finite-size scaling form of the survival probability in discrete time branching processes. In this comment, we generalize the argument to a wide range of continuous time branching processes. Owing to the continuity, the resulting differential (rather than difference) equations can be solved in closed form, rendering some approximations by R. Garcia-Millan et al. superfluous, although we work along similar lines. In the case of binary branching, our results are in fact exact. Demonstrating that discrete time and continuous time models have their leading order asymptotics in common, raises the question to what extent corrections are identical.

  2. A test of homogeneity for age-dependent branching processes with immigration

    PubMed Central

    Yanev, Nikolay M.; Jordan, Craig T.

    2016-01-01

    We propose a novel procedure to test whether the immigration process of a discretely observed age-dependent branching process with immigration is time-homogeneous. The construction of the test is motivated by the behavior of the coefficient of variation of the population size. When immigration is time-homogeneous, we find that this coefficient converges to a constant, whereas when immigration is time-inhomogeneous we find that it is time-dependent, at least transiently. Thus, we test the assumption that the immigration process is time-homogeneous by verifying that the sample coefficient of variation does not vary significantly over time. The test is simple to implement and does not require specification or fitting any branching process to the data. Simulations and an application to real data on the progression of leukemia are presented to illustrate the approach. PMID:27134694

  3. A test of homogeneity for age-dependent branching processes with immigration.

    PubMed

    Hyrien, Ollivier; Yanev, Nikolay M; Jordan, Craig T

    We propose a novel procedure to test whether the immigration process of a discretely observed age-dependent branching process with immigration is time-homogeneous. The construction of the test is motivated by the behavior of the coefficient of variation of the population size. When immigration is time-homogeneous, we find that this coefficient converges to a constant, whereas when immigration is time-inhomogeneous we find that it is time-dependent, at least transiently. Thus, we test the assumption that the immigration process is time-homogeneous by verifying that the sample coefficient of variation does not vary significantly over time. The test is simple to implement and does not require specification or fitting any branching process to the data. Simulations and an application to real data on the progression of leukemia are presented to illustrate the approach.

  4. Optimal Design of Multitype Groundwater Monitoring Networks Using Easily Accessible Tools.

    PubMed

    Wöhling, Thomas; Geiges, Andreas; Nowak, Wolfgang

    2016-11-01

    Monitoring networks are expensive to establish and to maintain. In this paper, we extend an existing data-worth estimation method from the suite of PEST utilities with a global optimization method for optimal sensor placement (called optimal design) in groundwater monitoring networks. Design optimization can include multiple simultaneous sensor locations and multiple sensor types. Both location and sensor type are treated simultaneously as decision variables. Our method combines linear uncertainty quantification and a modified genetic algorithm for discrete multilocation, multitype search. The efficiency of the global optimization is enhanced by an archive of past samples and parallel computing. We demonstrate our methodology for a groundwater monitoring network at the Steinlach experimental site, south-western Germany, which has been established to monitor river-groundwater exchange processes. The target of optimization is the best possible exploration for minimum variance in predicting the mean travel time of the hyporheic exchange. Our results demonstrate that the information gain of monitoring network designs can be explored efficiently and with easily accessible tools prior to taking new field measurements or installing additional measurement points. The proposed methods proved to be efficient and can be applied for model-based optimal design of any type of monitoring network in approximately linear systems. Our key contributions are (1) the use of easy-to-implement tools for an otherwise complex task and (2) yet to consider data-worth interdependencies in simultaneous optimization of multiple sensor locations and sensor types.

  5. Infrared and multi-type images fusion algorithm based on contrast pyramid transform

    NASA Astrophysics Data System (ADS)

    Xu, Hua; Wang, Yan; Wu, Yujing; Qian, Yunsheng

    2016-09-01

    A fusion algorithm for infrared and multi-type images based on contrast pyramid transform (CPT) combined with Otsu method and morphology is proposed in this paper. Firstly, two sharpened images are combined to the first fused image based on information entropy weighted scheme. Afterwards, two enhanced images and the first fused one are decomposed into a series of images with different dimensions and spatial frequencies. To the low-frequency layer, the Otsu method is applied to calculate the optimal segmentation threshold of the first fused image, which is subsequently used to determine the pixel values in top layer fused image. With respect to the high-frequency layers, the top-bottom hats morphological transform is employed to each layer before maximum selection criterion. Finally, the series of decomposed images are reconstructed and then superposed with the enhanced image processed by morphological gradient operation as a second fusion to get the final fusion image. Infrared and visible images fusion, infrared and low-light-level (LLL) images fusion, infrared intensity and infrared polarization images fusion, and multi-focus images fusion are discussed in this paper. Both experimental results and objective metrics demonstrate the effectiveness and superiority of the proposed algorithm over the conventional ones used to compare.

  6. Patterns of cranial shape diversification during the phylogenetic branching process of New World monkeys (Primates: Platyrrhini).

    PubMed

    Perez, S I; Klaczko, J; Rocatti, G; Dos Reis, S F

    2011-08-01

    One of the central topics in evolutionary biology is understanding the processes responsible for phenotypic diversification related to ecological factors. New World monkeys are an excellent reference system to investigate processes of diversification at macroevolutionary scales. Here, we investigate the cranial shape diversification related to body size and ecology during the phylogenetic branching process of platyrrhines. To investigate this diversification, we used geometric morphometric techniques, a molecular phylogenetic tree, ecological data and phylogenetic comparative methods. Our statistical analyses demonstrated that the phylogenetic branching process is the most important dimension to understand cranial shape variation among extant platyrrhines and suggested that the main shape divergence among the four principal platyrrhine clades probably occurred during the initial branching process. The phylogenetic conservatism, which is the retention of ancestral traits over time within the four principal platyrrhine clades, could be the most important characteristic of platyrrhine cranial shape diversification. Different factors might have driven early shape divergence and posterior relative conservatism, including genetic drift, stabilizing selection, genetic constraints owing to pleiotropy, developmental or functional constraint, lack of genetic variation, among others. Understanding the processes driving the diversification among platyrrhines will probably require further palaeontological, phylogenetic and comparative studies. © 2011 The Authors. Journal of Evolutionary Biology © 2011 European Society For Evolutionary Biology.

  7. Testing branching process estimators of cascading failure with data from a simulation of transmission line outages.

    PubMed

    Dobson, Ian; Kim, Janghoon; Wierzbicki, Kevin R

    2010-04-01

    We suggest a statistical estimator to quantify the propagation of cascading transmission line failures in large blackouts of electric power systems. We use a Galton-Watson branching process model of cascading failure and the standard Harris estimator of the mean propagation modified to work when the process saturates at a maximum number of components. If the mean number of initial failures and the mean propagation are estimated, then the branching process model predicts the distribution of the total number of failures. We initially test this prediction on failure data generated by a simulation of cascading transmission line outages on two standard test systems. We discuss the effectiveness of the estimator in terms of how many cascades need to be simulated to predict the distribution of the total number of line outages accurately.

  8. Anomalous power law distribution of total lifetimes of branching processes: application to earthquake aftershock sequences.

    PubMed

    Saichev, A; Sornette, D

    2004-10-01

    We consider a general stochastic branching process, which is relevant to earthquakes, and study the distributions of global lifetimes of the branching processes. In the earthquake context, this amounts to the distribution of the total durations of aftershock sequences including aftershocks of arbitrary generation number. Our results extend previous results on the distribution of the total number of offspring (direct and indirect aftershocks in seismicity) and of the total number of generations before extinction. We consider a branching model of triggered seismicity, the epidemic-type aftershock sequence model, which assumes that each earthquake can trigger other earthquakes ("aftershocks"). An aftershock sequence results in this model from the cascade of aftershocks of each past earthquake. Due to the large fluctuations of the number of aftershocks triggered directly by any earthquake ("productivity" or "fertility"), there is a large variability of the total number of aftershocks from one sequence to another, for the same mainshock magnitude. We study the regime where the distribution of fertilities mu is characterized by a power law approximately 1/ mu(1+gamma) and the bare Omori law for the memory of previous triggering mothers decays slowly as approximately 1/ t(1+theta;) , with 0branching ratio is critical (n=1) . The coefficient 1

  9. An analytical and numerical study of Galton-Watson branching processes relevant to population dynamics

    NASA Astrophysics Data System (ADS)

    Jang, Sa-Han

    Galton-Watson branching processes of relevance to human population dynamics are the subject of this thesis. We begin with an historical survey of the invention of the invention of this model in the middle of the 19th century, for the purpose of modelling the extinction of unusual surnames in France and Britain. We then review the principal developments and refinements of this model, and their applications to a wide variety of problems in biology and physics. Next, we discuss in detail the case where the probability generating function for a Galton-Watson branching process is a geometric series, which can be summed in closed form to yield a fractional linear generating function that can be iterated indefinitely in closed form. We then describe the matrix method of Keyfitz and Tyree, and use it to determine how large a matrix must be chosen to model accurately a Galton-Watson branching process for a very large number of generations, of the order of hundreds or even thousands. Finally, we show that any attempt to explain the recent evidence for the existence thousands of generations ago of a 'mitochondrial Eve' and a 'Y-chromosomal Adam' in terms of a the standard Galton-Watson branching process, or indeed any statistical model that assumes equality of probabilities of passing one's genes to one's descendents in later generations, is unlikely to be successful. We explain that such models take no account of the advantages that the descendents of the most successful individuals in earlier generations enjoy over their contemporaries, which must play a key role in human evolution.

  10. Simple unified view of branching process statistics: Random walks in balanced logarithmic potentials

    NASA Astrophysics Data System (ADS)

    di Santo, Serena; Villegas, Pablo; Burioni, Raffaella; Muñoz, Miguel A.

    2017-03-01

    We revisit the problem of deriving the mean-field values of avalanche exponents in systems with absorbing states. These are well known to coincide with those of unbiased branching processes. Here we show that for at least four different universality classes (directed percolation, dynamical percolation, the voter model or compact directed percolation class, and the Manna class of stochastic sandpiles) this common result can be obtained by mapping the corresponding Langevin equations describing each of them into a random walker confined to the origin by a logarithmic potential. We report on the emergence of nonuniversal continuously varying exponent values stemming from the presence of small external driving - that might induce avalanche merging - that, to the best of our knowledge, has not been noticed in the past. Many of the other results derived here appear in the literature as independently derived for individual universality classes or for the branching process itself. Still, we believe that a simple and unified perspective as the one presented here can help (1) clarify the overall picture, (2) underline the superuniversality of the behavior as well as the dependence on external driving, and (3) avoid the common existing confusion between unbiased branching processes (equivalent to a random walker in a balanced logarithmic potential) and standard (unconfined) random walkers.

  11. Simple unified view of branching process statistics: Random walks in balanced logarithmic potentials.

    PubMed

    di Santo, Serena; Villegas, Pablo; Burioni, Raffaella; Muñoz, Miguel A

    2017-03-01

    We revisit the problem of deriving the mean-field values of avalanche exponents in systems with absorbing states. These are well known to coincide with those of unbiased branching processes. Here we show that for at least four different universality classes (directed percolation, dynamical percolation, the voter model or compact directed percolation class, and the Manna class of stochastic sandpiles) this common result can be obtained by mapping the corresponding Langevin equations describing each of them into a random walker confined to the origin by a logarithmic potential. We report on the emergence of nonuniversal continuously varying exponent values stemming from the presence of small external driving - that might induce avalanche merging - that, to the best of our knowledge, has not been noticed in the past. Many of the other results derived here appear in the literature as independently derived for individual universality classes or for the branching process itself. Still, we believe that a simple and unified perspective as the one presented here can help (1) clarify the overall picture, (2) underline the superuniversality of the behavior as well as the dependence on external driving, and (3) avoid the common existing confusion between unbiased branching processes (equivalent to a random walker in a balanced logarithmic potential) and standard (unconfined) random walkers.

  12. Process for the conversion of lower alcohols to higher branched oxygenates

    DOEpatents

    Barger, P.T.

    1996-09-24

    A process is provided for the production of branched C{sub x} oxygenates from lower alcohols such as methanol, ethanol, propanol and mixtures thereof. The process comprises contacting the lower alcohols with a solid catalyst comprising a mixed metal oxide support having components selected from the group consisting of oxides of zinc, magnesium, zirconia, titanium, manganese, chromium, and lanthanides, and an activation metal selected from the group consisting of Group VIII metal, Group IB metals, and mixtures thereof. The advantage of the process is improved yields and selectivity to isobutanol which can subsequently be employed in the production of high octane motor gasoline.

  13. Process for the conversion of lower alcohols to higher branched oxygenates

    DOEpatents

    Barger, Paul T.

    1996-01-01

    A process is provided for the production of branched C.sub.4+ oxygenates from lower alcohols such as methanol, ethanol, propanol and mixtures thereof. The process comprises contacting the lower alcohols with a solid catalyst comprising a mixed metal oxide support having components selected from the group consisting of oxides of zinc, magnesium, zirconia, titanium, manganese, chromium, and lanthanides, and an activation metal selected from the group consisting of Group VIII metal, Group IB metals, and mixtures thereof. The advantage of the process is improved yields and selectivity to isobutanol which can subsequently be employed in the production of high octane motor gasoline.

  14. Strategic Planning for Library Multitype Cooperatives: Samples & Examples. ASCLA Changing Horizons Series #1.

    ERIC Educational Resources Information Center

    Baughman, Steven A., Ed.; Curry, Elizabeth A., Ed.

    As interlibrary cooperation has proliferated in the last several decades, multitype library organizations and systems have emerged as important forces in librarianship. The need for thoughtful and organized strategic planning is an important cornerstone for the success of organizations of all sizes. Part of a project by the Interlibrary…

  15. Life spans of a Bellman-Harris branching process with immigration

    SciTech Connect

    Badalbaev, I.S.; Mashrabbaev, A.

    1987-09-10

    One considers two schemes of the Bellman-Harris process with immigration when a) the lifetime of the particles is an integral-valued random variable and the immigration is defined by a sequence of independent random variables; b) the distribution of the lifetime of the particles is nonlattice and the immigration is a process with continuous time. One investigates the properties of the life spans of such processes. The results obtained here are a generalization to the case of Bellman-Harris processes of the results of A.M. Zubkov, obtained for Markov branching processes. For the proof one makes use in an essential manner of the known inequalities of Goldstein, estimating the generating function of the Bellman-Harris process in terms of the generating functions of the imbedded Galton-Watson process.

  16. Branching-ratio approximation for the self-exciting Hawkes process

    NASA Astrophysics Data System (ADS)

    Hardiman, Stephen J.; Bouchaud, Jean-Philippe

    2014-12-01

    We introduce a model-independent approximation for the branching ratio of Hawkes self-exciting point processes. Our estimator requires knowing only the mean and variance of the event count in a sufficiently large time window, statistics that are readily obtained from empirical data. The method we propose greatly simplifies the estimation of the Hawkes branching ratio, recently proposed as a proxy for market endogeneity and formerly estimated using numerical likelihood maximization. We employ our method to support recent theoretical and experimental results indicating that the best fitting Hawkes model to describe S&P futures price changes is in fact critical (now and in the recent past) in light of the long memory of financial market activity.

  17. SDF1 regulates leading process branching and speed of migrating interneurons

    PubMed Central

    Lysko, Daniel E.; Putt, Mary; Golden, Jeffrey A.

    2011-01-01

    Cell migration is required for normal embryonic development, yet how cells navigate complex paths while integrating multiple guidance cues remains poorly understood. During brain development, interneurons migrate from the ventral ganglionic eminence to the cerebral cortex within several migratory streams. They must exit these streams to invade the cortical plate. While SDF1-signaling is necessary for normal interneuron stream migration, how they switch from tangential stream migration to invade the cortical plate is unknown. Here we demonstrate that SDF1-signaling reduces interneuron branching frequency by reducing cAMP levels via a Gi-signaling pathway using an in vitro mouse explant system, resulting in the maintenance of stream migration. Blocking SDF1-signaling, or increasing branching frequency, results in stream exit and cortical plate invasion in mouse brain slices. These data support a novel model to understand how migrating interneurons switch from tangential migration to invade the cortical plate in which reducing SDF1-signaling increases leading process branching and slows the migration rate, permitting migrating interneurons to sense cortically directed guidance cues. PMID:21289183

  18. Study on color identification for monitoring and controlling fermentation process of branched chain amino acid

    NASA Astrophysics Data System (ADS)

    Ma, Lei; Wang, Yizhong; Chen, Ning; Liu, Tiegen; Xu, Qingyang; Kong, Fanzhi

    2008-12-01

    In this paper, a new method for monitoring and controlling fermentation process of branched chain amino acid (BCAA) was proposed based on color identification. The color image of fermentation broth of BCAA was firstly taken by a CCD camera. Then, it was changed from RGB color model to HIS color model. Its histograms of hue H and saturation S were calculated, which were used as the input of a designed BP network. The output of the BP network was the description of the color of fermentation broth of BCAA. After training, the color of fermentation broth was identified by the BP network according to the histograms of H and S of a fermentation broth image. Along with other parameters, the fermentation process of BCAA was monitored and controlled to start the stationary phase of fermentation soon. Experiments were conducted with satisfied results to show the feasibility and usefulness of color identification of fermentation broth in fermentation process control of BCAA.

  19. Discriminating between Weibull distributions and log-normal distributions emerging in branching processes

    NASA Astrophysics Data System (ADS)

    Goh, Segun; Kwon, H. W.; Choi, M. Y.

    2014-06-01

    We consider the Yule-type multiplicative growth and division process, and describe the ubiquitous emergence of Weibull and log-normal distributions in a single framework. With the help of the integral transform and series expansion, we show that both distributions serve as asymptotic solutions of the time evolution equation for the branching process. In particular, the maximum likelihood method is employed to discriminate between the emergence of the Weibull distribution and that of the log-normal distribution. Further, the detailed conditions for the distinguished emergence of the Weibull distribution are probed. It is observed that the emergence depends on the manner of the division process for the two different types of distribution. Numerical simulations are also carried out, confirming the results obtained analytically.

  20. Oscillatory Critical Amplitudes in Hierarchical Models and the Harris Function of Branching Processes

    NASA Astrophysics Data System (ADS)

    Costin, Ovidiu; Giacomin, Giambattista

    2013-02-01

    Oscillatory critical amplitudes have been repeatedly observed in hierarchical models and, in the cases that have been taken into consideration, these oscillations are so small to be hardly detectable. Hierarchical models are tightly related to iteration of maps and, in fact, very similar phenomena have been repeatedly reported in many fields of mathematics, like combinatorial evaluations and discrete branching processes. It is precisely in the context of branching processes with bounded off-spring that T. Harris, in 1948, first set forth the possibility that the logarithm of the moment generating function of the rescaled population size, in the super-critical regime, does not grow near infinity as a power, but it has an oscillatory prefactor (the Harris function). These oscillations have been observed numerically only much later and, while the origin is clearly tied to the discrete character of the iteration, the amplitude size is not so well understood. The purpose of this note is to reconsider the issue for hierarchical models and in what is arguably the most elementary setting—the pinning model—that actually just boils down to iteration of polynomial maps (and, notably, quadratic maps). In this note we show that the oscillatory critical amplitude for pinning models and the Harris function coincide. Moreover we make explicit the link between these oscillatory functions and the geometry of the Julia set of the map, making thus rigorous and quantitative some ideas set forth in Derrida et al. (Commun. Math. Phys. 94:115-132, 1984).

  1. Symmetry, randomness, and process in the structure of branched channel networks

    NASA Astrophysics Data System (ADS)

    Shelef, Eitan; Hilley, George E.

    2014-05-01

    The branched structure of channel networks has a primary impact on the spatial distribution of elevation, water, and life across Earth's surface from the hillslope to the continental scale and is also observed on other planets. However, the link between this dendritic multiscale structure and the erosional processes that sculpt it has remained elusive for more than six decades. In fact, many topologic measures fail to distinguish natural networks from those generated by random walks. Here we show that a fundamental multiscale topologic symmetry is ingrained into the structure of these networks and reflects the equal elevation drop spanned by flows that split at the drainage divide and meet again downslope. We demonstrate that this symmetry distinguishes random-walk networks from natural ones, captures the temporal evolution of these networks, and divulges information about the processes that shape them.

  2. Bayesian analysis of multi-type recurrent events and dependent termination with nonparametric covariate functions

    PubMed Central

    Lin, Li-An; Luo, Sheng; Chen, Bingshu E.; Davis, Barry R.

    2016-01-01

    Multi-type recurrent event data occur frequently in longitudinal studies. Dependent termination may occur when the terminal time is correlated to recurrent event times. In this article, we simultaneously model the multi-type recurrent events and a dependent terminal event, both with nonparametric covariate functions modeled by B-splines. We develop a Bayesian multivariate frailty model to account for the correlation among the dependent termination and various types of recurrent events. Extensive simulation results suggest that misspecifying nonparametric covariate functions may introduce bias in parameter estimation. This method development has been motivated by and applied to the lipid-lowering trial (LLT) component of the Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial (ALLHAT). PMID:26546256

  3. [The organization of system of quality management in large multitype hospital].

    PubMed

    Taĭts, B M; Krichmar, G N; Stvolinskiĭ, I Iu; Grandilevskaia, O L

    2013-01-01

    The article presents the characteristics and assessment of functioning of model of quality management in large multitype hospital. The results of work of the municipal hospital of Saint Venerable martyr Elizabeth of St Petersburg concerning the implementation of system of quality management in 2001-2011 of the foundation of principles of total quality management of medical service and principles of quality management according international standards ISO and their Russian analogues.

  4. Extreme Events and Their Predictability in a Branching Diffusion Model

    NASA Astrophysics Data System (ADS)

    Gabrielov, A.; Zaliapin, I.; Keilis-Borok, V.

    2009-05-01

    Studies in prediction of extreme events, based on real observations and numerical modeling of complex systems, suggest universal patterns of system's behavior signaling approach of an extreme event. These patterns include deviation from self-similarity, increase in background activity, clustering, and long-range correlation. In the absence of a closed theory describing critical transitions in complex systems, and with insufficient and noisy observations, numerical parameters of the patterns have to be data-fitted, creating the risk of self-deception ("With four exponents I can fit the elephant" - J. von Neumann). Here, we introduce a model which provides analytical definition of at least two parameters, intensity and deviation from self-similarity. That drastically reduces non-uniqueness of parametrization, suggesting a simple universal mechanism of premonitory patterns and natural framework for their analytical study. Major conceptual parts of the model - direct cascading or fragmentation, spatial dynamics, and external driving - are combined in a classical age-dependent multi-type branching diffusion process with immigration. A complete analytic description of the size- and space-dependent distributions of particles and their correlations is derived using the generating function approach.

  5. A method of reconstructing complex stratigraphic surfaces with multitype fault constraints

    NASA Astrophysics Data System (ADS)

    Deng, Shi-Wu; Jia, Yu; Yao, Xing-Miao; Liu, Zhi-Ning

    2017-06-01

    The construction of complex stratigraphic surfaces is widely employed in many fields, such as petroleum exploration, geological modeling, and geological structure analysis. It also serves as an important foundation for data visualization and visual analysis in these fields. The existing surface construction methods have several deficiencies and face various difficulties, such as the presence of multitype faults and roughness of resulting surfaces. In this paper, a surface modeling method that uses geometric partial differential equations (PDEs) is introduced for the construction of stratigraphic surfaces. It effectively solves the problem of surface roughness caused by the irregularity of stratigraphic data distribution. To cope with the presence of multitype complex faults, a two-way projection algorithm between threedimensional space and a two-dimensional plane is proposed. Using this algorithm, a unified method based on geometric PDEs is developed for dealing with multitype faults. Moreover, the corresponding geometric PDE is derived, and an algorithm based on an evolutionary solution is developed. The algorithm proposed for constructing spatial surfaces with real data verifies its computational efficiency and its ability to handle irregular data distribution. In particular, it can reconstruct faulty surfaces, especially those with overthrust faults.

  6. Coherence and Incoherence in QCD Jets Dynamics (QCD Jets and Branching Processes)

    NASA Astrophysics Data System (ADS)

    Giovannini, A.; Ugoccioni, R.

    The interpretation of QCD jets as Markov branching processes obtained by solving Konishi Ukawa Veneziano equations [1] in the leading logarithmic approximation with a fixed cut-off regularization prescription [2] is reviewed, and its impact in multiparticle dynamics critically examined. Independent intermediate gluon sources (clans) are generated through quark bremsstrahlung, each source then decays into final partons according to a cascading mechanism dominated by gluon self-interaction. At the hadron level, approximate universal regularities are expected in the different components (or substructures) of the various classes of high-energy collisions. The general behavior of collective variables of final multiplicity distributions is reproduced in terms of the weighted superposition of the above-mentioned regularities controlling the component behaviors of each collision. Predictions of signals of new physics at LHC [3] are reviewed, and perspective of the 1/N expansion approach [4] indicated.

  7. Exact solution of a two-type branching process: clone size distribution in cell division kinetics

    NASA Astrophysics Data System (ADS)

    Antal, Tibor; Krapivsky, P. L.

    2010-07-01

    We study a two-type branching process which provides an excellent description of experimental data on cell dynamics in skin tissue. The model involves only a single type of progenitor cell, that is it does not require support from a self-renewed population of stem cells. The progenitor cells divide and may differentiate into post-mitotic cells. We derive an exact solution for the generating function of the number of cells of different types. The generating function is then used to numerically determine the time dependent probability distribution of the numbers of the two types of cells. We also deduce large time asymptotic behaviors drawing on exact results and on a diffusion approximation.

  8. Growth rate and shape as possible control mechanisms for the selection of mode development in optimal biological branching processes

    NASA Astrophysics Data System (ADS)

    Alarcón, Tomás; Castillo, Jorge; García-Ponce, Berenice; Herrero, Miguel Angel; Padilla, Pablo

    2016-11-01

    Recently three branching modes were characterized during the formation of the lung in mice. These modes are highly stereotyped and correspond to domain formation, planar bifurcation and three dimensional branching respectively. At the same time it is proved that although genetic control mechanisms are presumably related to the selection of any of these modes, other external factors will most probably be involved in the branching process during development. In this paper we propose that the underlying controling factors might be related to the rate at which the tubes that form the lung network grow. We present a mathematical model that allows us to formulate specific experimental predictions on these growth rates. Moreover we show that according to this formulation, there is an optimization criterion which governs the branching process during lung development, namely, efficient local space filling properties of the network. If there is no space limitation the branches are allowed to grow freely and faster, selecting one branching mode, namely, domain formation. As soon as volume constraints appear the growth rate decreases, triggering the selection of planar and orthogonal bifurcation.

  9. Living in the branches: population dynamics and ecological processes in dendritic networks

    USGS Publications Warehouse

    Grant, E.H.C.; Lowe, W.H.; Fagan, W.F.

    2007-01-01

    Spatial structure regulates and modifies processes at several levels of ecological organization (e.g. individual/genetic, population and community) and is thus a key component of complex systems, where knowledge at a small scale can be insufficient for understanding system behaviour at a larger scale. Recent syntheses outline potential applications of network theory to ecological systems, but do not address the implications of physical structure for network dynamics. There is a specific need to examine how dendritic habitat structure, such as that found in stream, hedgerow and cave networks, influences ecological processes. Although dendritic networks are one type of ecological network, they are distinguished by two fundamental characteristics: (1) both the branches and the nodes serve as habitat, and (2) the specific spatial arrangement and hierarchical organization of these elements interacts with a species' movement behaviour to alter patterns of population distribution and abundance, and community interactions. Here, we summarize existing theory relating to ecological dynamics in dendritic networks, review empirical studies examining the population- and community-level consequences of these networks, and suggest future research integrating spatial pattern and processes in dendritic systems.

  10. Branching process deconvolution algorithm reveals a detailed cell-cycle transcription program.

    PubMed

    Guo, Xin; Bernard, Allister; Orlando, David A; Haase, Steven B; Hartemink, Alexander J

    2013-03-05

    Due to cell-to-cell variability and asymmetric cell division, cells in a synchronized population lose synchrony over time. As a result, time-series measurements from synchronized cell populations do not reflect the underlying dynamics of cell-cycle processes. Here, we present a branching process deconvolution algorithm that learns a more accurate view of dynamic cell-cycle processes, free from the convolution effects associated with imperfect cell synchronization. Through wavelet-basis regularization, our method sharpens signal without sharpening noise and can remarkably increase both the dynamic range and the temporal resolution of time-series data. Although applicable to any such data, we demonstrate the utility of our method by applying it to a recent cell-cycle transcription time course in the eukaryote Saccharomyces cerevisiae. Our method more sensitively detects cell-cycle-regulated transcription and reveals subtle timing differences that are masked in the original population measurements. Our algorithm also explicitly learns distinct transcription programs for mother and daughter cells, enabling us to identify 82 genes transcribed almost entirely in early G1 in a daughter-specific manner.

  11. Improved zeolite regeneration processes for preparing saturated branched-chain fatty acids

    USDA-ARS?s Scientific Manuscript database

    Ferrierite zeolite solid is an excellent catalyst for the skeletal isomerization of unsaturated linear-chain fatty acids (i.e., oleic acid) to unsaturated branched-chain fatty acids (i.e., iso-oleic acid) follow by hydrogenation to give saturated branched-chain fatty acids (i.e., isostearic acid). ...

  12. Crystal structure and functional implications of Pyrococcus furiosus hef helicase domain involved in branched DNA processing.

    PubMed

    Nishino, Tatsuya; Komori, Kayoko; Tsuchiya, Daisuke; Ishino, Yoshizumi; Morikawa, Kosuke

    2005-01-01

    DNA and RNA frequently form various branched intermediates that are important for the transmission of genetic information. Helicases play pivotal roles in the processing of these transient intermediates during nucleic acid metabolism. The archaeal Hef helicase/ nuclease is a representative protein that processes flap- or fork-DNA structures, and, intriguingly, its C-terminal half belongs to the XPF/Mus81 nuclease family. Here, we report the crystal structure of the helicase domain of the Hef protein from Pyrococcus furiosus. The structure reveals a novel helical insertion between the two conserved helicase core domains. This positively charged extra region, structurally similar to the "thumb" domain of DNA polymerase, plays critical roles in fork recognition. The Hef helicase/nuclease exhibits sequence similarity to the Mph1 helicase from Saccharomyces cerevisiae; XPF/Rad1, involved in DNA repair; and a putative Hef homolog identified in mammals. Hence, our findings provide a structural basis for the functional mechanisms of this helicase/nuclease family.

  13. A branching process, its application in biology: influence of demographic parameters on the social structure in mammal groups.

    PubMed

    Caron-Lormier, G; Masson, J P; Ménard, N; Pierre, J S

    2006-02-07

    Branching processes are widely used in biology. This theoretical tool is used in cell dynamics, epidemics and population dynamics. In population dynamics, branching processes are mainly used to access extinction probabilities of populations, groups or families, with the Galton-Watson branching process. Many mammal species live in socially-structured groups, and the smallest units of these groups are lineages (or families) of kin-related individuals. In many primate species, these lineages are matrilines, as females remain in their natal groups most of the time, whereas males generally disperse. Lineage parameters, such as numbers of matrilines, size of each matriline and average degree of relatedness, could strongly influence the genetic composition of groups. Evidence indicates that division along matrilines could induce substantial differentiation among fission groups. Here, we develop a novel mathematical model based on the branching process theory describing demographic dynamics of groups. The main result of this model is an explicit analytical expression of the joint distribution of numbers of lineages and sizes of socially-structured groups. We investigated the influence of parameters such as natality and mortality on the outcome of the process, including extinction probability. Finally, we discuss this theoretical result with respect to biological significance.

  14. Multi-type Childhood Abuse, Strategies of Coping, and Psychological Adaptations in Young Adults

    PubMed Central

    Sesar, Kristina; Šimić, Nataša; Barišić, Marijana

    2010-01-01

    Aim To retrospectively analyze the rate of multi-type abuse in childhood and the effects of childhood abuse and type of coping strategies on the psychological adaptation of young adults in a sample form the student population of the University of Mostar. Methods The study was conducted on a convenience sample of 233 students from the University of Mostar (196 female and 37 male), with a median age of 20 (interquartile range, 2). Exposure to abuse was determined using the Child Maltreatment Scales for Adults, which assesses emotional, physical, and sexual abuse, neglect, and witnessing family violence. Psychological adaptation was explored by the Trauma Symptom Checklist, which assesses anxiety/depression, sexual problems, trauma symptoms, and somatic symptoms. Strategies of coping with stress were explored by the Coping Inventory for Stressful Situations. Results Multi-type abuse in childhood was experienced by 172 participants (74%) and all types of abuse by 11 (5%) participants. Emotional and physical maltreatment were the most frequent types of abuse and mostly occurred together with other types of abuse. Significant association was found between all types of abuse (r = 0.436-0.778, P < 0.050). Exposure to sexual abuse in childhood and coping strategies were significant predictors of anxiety/depression (R2 = 0.3553), traumatic symptoms (R2 = 0.2299), somatic symptoms (R2 = 0.2173), and sexual problems (R2 = 0.1550, P < 0.001). Conclusion Exposure to multi-type abuse in childhood is a traumatic experience with long-term negative effects. Problem-oriented coping strategies ensure a better psychosocial adaptation than emotion-oriented strategies. PMID:20960590

  15. The Effects of Rotation on s-process Nucleosynthesis in Asymptotic Giant Branch Stars

    NASA Astrophysics Data System (ADS)

    Piersanti, L.; Cristallo, S.; Straniero, O.

    2013-09-01

    In this paper, we analyze the effects induced by rotation on low-mass asymptotic giant branch stars. We compute two sets of models, M = 2.0 M ⊙ at [Fe/H] = 0 and M = 1.5 M ⊙ at [Fe/H] = -1.7, by adopting main-sequence rotation velocities in the range 0-120 km s-1. At high metallicity, we find that the Goldreich-Schubert-Fricke instability, active at the interface between the convective envelope and the rapid rotating core, contaminates the 13C-pocket (the major neutron source) with 14N (the major neutron poison), thus reducing the neutron flux available for the synthesis of heavy elements. As a consequence, the yields of heavy-s elements (Ba, La, Nd, Sm) and, to a lesser extent, those of light-s elements (Sr, Y, Zr) decrease with increasing rotation velocities up to 60 km s-1. However, for larger initial rotation velocities, the production of light-s and, to a lesser extent, that of heavy-s, begins again to increase, due to mixing induced by meridional circulations. At low metallicity, the effects of meridional circulations are important even at rather low rotation velocity. The combined effect of the Goldreich-Schubert-Fricke instability and meridional circulations determines an increase of light-s and, to a lesser extent, heavy-s elements, while lead is strongly reduced. For both metallicities, the rotation-induced instabilities active during the interpulse phase reduce the neutron-to-seed ratio, so that the spectroscopic indexes [hs/ls] and [Pb/hs] decrease by increasing the initial rotation velocity. Our analysis suggests that rotation could explain the spread in the s-process indexes, as observed in s-process enriched stars at different metallicities.

  16. THE EFFECTS OF ROTATION ON s-PROCESS NUCLEOSYNTHESIS IN ASYMPTOTIC GIANT BRANCH STARS

    SciTech Connect

    Piersanti, L.; Cristallo, S.; Straniero, O.

    2013-09-10

    In this paper, we analyze the effects induced by rotation on low-mass asymptotic giant branch stars. We compute two sets of models, M = 2.0 M{sub Sun} at [Fe/H] = 0 and M = 1.5 M{sub Sun} at [Fe/H] = -1.7, by adopting main-sequence rotation velocities in the range 0-120 km s{sup -1}. At high metallicity, we find that the Goldreich-Schubert-Fricke instability, active at the interface between the convective envelope and the rapid rotating core, contaminates the {sup 13}C-pocket (the major neutron source) with {sup 14}N (the major neutron poison), thus reducing the neutron flux available for the synthesis of heavy elements. As a consequence, the yields of heavy-s elements (Ba, La, Nd, Sm) and, to a lesser extent, those of light-s elements (Sr, Y, Zr) decrease with increasing rotation velocities up to 60 km s{sup -1}. However, for larger initial rotation velocities, the production of light-s and, to a lesser extent, that of heavy-s, begins again to increase, due to mixing induced by meridional circulations. At low metallicity, the effects of meridional circulations are important even at rather low rotation velocity. The combined effect of the Goldreich-Schubert-Fricke instability and meridional circulations determines an increase of light-s and, to a lesser extent, heavy-s elements, while lead is strongly reduced. For both metallicities, the rotation-induced instabilities active during the interpulse phase reduce the neutron-to-seed ratio, so that the spectroscopic indexes [hs/ls] and [Pb/hs] decrease by increasing the initial rotation velocity. Our analysis suggests that rotation could explain the spread in the s-process indexes, as observed in s-process enriched stars at different metallicities.

  17. Synthesis of porous carbon nanofiber with bamboo-like carbon nanofiber branches by one-step carbonization process

    NASA Astrophysics Data System (ADS)

    Yoo, Seung Hwa; Joh, Han-Ik; Lee, Sungho

    2017-04-01

    Porous carbon nanofibers (PCNFs) with CNF branches (PCNF/bCNF) were synthesized by a simple heat treatment method. Conventional methods to synthesize this unique structure usually follow a typical route, which consists of CNF preparation, catalyst deposition, and secondary CNF growth. In contrast, our method utilized a one-step carbonization process of polymer nanofibers, which were electrospun from a one-pot solution consisted of polyacrylonitrile, polystyrene (PS), and iron acetylacetonate. Various structures of PCNF/CNF were synthesized by changing the solution composition and molecular weight of PS. It was verified that the content and molecular weight of PS were critical for the growth of catalyst particles and subsequent growth of CNF branches. The morphology, phase of catalyst, and carbon structure of PCNF/bCNF were analyzed at different temperature steps during carbonization. It was found that pores were generated by the evaporation of PS and the catalyst particles were formed on the surface of PCNF at 700 °C. The gases originated from the evaporation of PS acted as a carbon source for the growth of CNF branches that started at 900 °C. Finally, when the carbonization process was finished at 1200 °C, uniform and abundant CNF branches were formed on the surface of PCNF.

  18. Communication, Collaboration and Cooperation: An Evaluation of Nova Scotia's Borrow Anywhere, Return Anywhere (BARA) Multi-Type Library Initiative

    ERIC Educational Resources Information Center

    van den Hoogen, Suzanne; Parrott, Denise

    2012-01-01

    Partnerships and collaborations among libraries are proven to enhance collective resources. The collaboration of multi-type libraries offers a unique opportunity to explore the potential of different libraries working together to provide the best possible service to their community members. This article provides a detailed report of a multi-type…

  19. Communication, Collaboration and Cooperation: An Evaluation of Nova Scotia's Borrow Anywhere, Return Anywhere (BARA) Multi-Type Library Initiative

    ERIC Educational Resources Information Center

    van den Hoogen, Suzanne; Parrott, Denise

    2012-01-01

    Partnerships and collaborations among libraries are proven to enhance collective resources. The collaboration of multi-type libraries offers a unique opportunity to explore the potential of different libraries working together to provide the best possible service to their community members. This article provides a detailed report of a multi-type…

  20. Child Multi-Type Maltreatment and Associated Depression and PTSD Symptoms: The Role of Social Support and Stress

    ERIC Educational Resources Information Center

    Vranceanu, Ana-Maria; Hobfoll, Stevan E.; Johnson, Robert J.

    2007-01-01

    Objective: This retrospective, cross-sectional study explored the hypothesis that multiple forms of child abuse and neglect (child multi-type maltreatment; CMM) would be associated with women's lower social support and higher stress in adulthood, and that this, in turn, would amplify their vulnerability to symptoms of depression and posttraumatic…

  1. Techno-economic analysis of an improved process for producing saturated branched-chain fatty acids

    USDA-ARS?s Scientific Manuscript database

    Vegetable oils provide a source of environmentally desirable lubricants, but they are not widely utilized because of their poor oxidative stability. Branched-chain fatty acid isomers are desirable products because they have excellent thermostabilities and lubricities when compared to the parent veg...

  2. Development and Potential of a Multitype Library Network.

    ERIC Educational Resources Information Center

    Kolb, Audrey

    1977-01-01

    Describes the larger service units, data processing technology, network appraisal, legal base, membership, organizational structure, and current and future school participation of the Washington Library Network. Sources of information about the Network are also provided. (CMV)

  3. 36 CFR § 1260.78 - What is the appeal process when an MDR request for Executive Branch information in NARA's legal...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Review (MDR) § 1260.78 What is the appeal process when an MDR request for Executive Branch information in... 36 Parks, Forests, and Public Property 3 2013-07-01 2012-07-01 true What is the appeal process when an MDR request for Executive Branch information in NARA's legal custody is denied in whole or in...

  4. 36 CFR 1260.78 - What is the appeal process when an MDR request for Executive Branch information in NARA's legal...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Review (MDR) § 1260.78 What is the appeal process when an MDR request for Executive Branch information in... 36 Parks, Forests, and Public Property 3 2014-07-01 2014-07-01 false What is the appeal process when an MDR request for Executive Branch information in NARA's legal custody is denied in whole or in...

  5. 36 CFR 1260.78 - What is the appeal process when an MDR request for Executive Branch information in NARA's legal...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Review (MDR) § 1260.78 What is the appeal process when an MDR request for Executive Branch information in... 36 Parks, Forests, and Public Property 3 2012-07-01 2012-07-01 false What is the appeal process when an MDR request for Executive Branch information in NARA's legal custody is denied in whole or in...

  6. On the inclusion of self regulating branching processes in the working paradigm of evolutionary and population genetics

    PubMed Central

    Mode, Charles J.; Sleeman, Candace K.; Raj, Towfique

    2013-01-01

    The principal goal of this methodological paper is to suggest to a general audience in the genetics community that the consideration of recent developments of self regulating branching processes may lead to the possibility of including this class of stochastic processes as part of working paradigm of evolutionary and population genetics. This class of branching processes is self regulating in the sense that an evolving population will grow only to a total population size that can be sustained by the environment. From the mathematical point of view the class processes under consideration belongs to a subfield of probability and statistics sometimes referred to as computational applied probability and stochastic processes. Computer intensive methods based on Monte Carlo simulation procedures have been used to empirically work out the predictions of a formulation by assigning numerical values to some point in the parameter space and computing replications of realizations of the process over thousands of generations of evolution. Statistical methods are then used on such samples of simulated data to produce informative summarizations of the data that provide insights into the evolutionary implications of computer experiments. Briefly, it is also possible to embed deterministic non-linear difference equations in the stochastic process by using a statistical procedure to estimate the sample functions of the process, which has interesting methodological implications as to whether stochastic or deterministic formulations may be applied separately or in combination in the study of evolution. It is recognized that the literature on population genetics contains a substantial number of papers in which Monte Carlo simulation methods have been used. But, this extensive literature is beyond the scope of this paper, which is focused on potential applications of self regulating branching processes in evolutionary and population genetics. PMID:23424044

  7. On the inclusion of self regulating branching processes in the working paradigm of evolutionary and population genetics.

    PubMed

    Mode, Charles J; Sleeman, Candace K; Raj, Towfique

    2013-01-01

    The principal goal of this methodological paper is to suggest to a general audience in the genetics community that the consideration of recent developments of self regulating branching processes may lead to the possibility of including this class of stochastic processes as part of working paradigm of evolutionary and population genetics. This class of branching processes is self regulating in the sense that an evolving population will grow only to a total population size that can be sustained by the environment. From the mathematical point of view the class processes under consideration belongs to a subfield of probability and statistics sometimes referred to as computational applied probability and stochastic processes. Computer intensive methods based on Monte Carlo simulation procedures have been used to empirically work out the predictions of a formulation by assigning numerical values to some point in the parameter space and computing replications of realizations of the process over thousands of generations of evolution. Statistical methods are then used on such samples of simulated data to produce informative summarizations of the data that provide insights into the evolutionary implications of computer experiments. Briefly, it is also possible to embed deterministic non-linear difference equations in the stochastic process by using a statistical procedure to estimate the sample functions of the process, which has interesting methodological implications as to whether stochastic or deterministic formulations may be applied separately or in combination in the study of evolution. It is recognized that the literature on population genetics contains a substantial number of papers in which Monte Carlo simulation methods have been used. But, this extensive literature is beyond the scope of this paper, which is focused on potential applications of self regulating branching processes in evolutionary and population genetics.

  8. Natural and anthropogenic multi-type hazards for loess territories

    NASA Astrophysics Data System (ADS)

    Mavlyanova, Nadira; Zakirova, Zulfiya

    2013-04-01

    Central Asia (CA) is an extremely large region of varied geography from plains to high, rugged mountains (the region belongs to the Tien-Shan and Pamirs mountain system), vast deserts (Kara Kum, Kyzyl Kum, Taklamakan). The area of the CA region is including the territories of following countries: of Kazakhstan, Kyrgyzstan, Tajikistan, Turkmenistan and Uzbekistan. CA is particularly exposed to natural hazards like earthquakes, landslide, rockfalls, avalanches, mudflows, flooding, high mountains lakes, sub flooding, and debris flow. This region is one of the most seismically active in the world. In XX century almost in each of five countries have occurred strong earthquakes with magnitude more than 7, led to human victims. Loess soils are widespread in this region in foothills, foothill plains and intermountain depressions. Loess can cause a number of engineering problems because loess undergoes structural collapse and subsidence due to saturation when both the initial dry density and initial water content are low. By comparison of the map of seismic zoning to a map of distribution of loess soils it is easy to be convinced that the territory of the majority of seismic areas are covering by collapsible loess soils with significant thickness (50-150 m). The natural hazards leads to a disaster, if it develops in an urbanized or industrial areas and directly affects people and economic objects. In this case, risk takes place with all its consequences especially on loess soil. In the past a formation of natural hazards was connected generally with two main groups of factors: geological structure and climatic conditions. Now to them the third factor - of human made influence was added. Intensive influence of human activity to the loess territories in CA for last 60 years is destruction of nature balance and changing in environment of loess land in zone with high seismic hazard. This processes primarily associated with following: 1) irrigation of new lands; 2) the

  9. Bi-directional processing of pri-miRNAs with branched terminal loops by Arabidopsis Dicer-like1

    PubMed Central

    Zhu, Hongliang; Zhou, Yuyi; Castillo-González, Claudia; Lu, Amber; Ge, Chunxiao; Zhao, Ying-Tao; Duan, Liusheng; Li, Zhaohu; Axtell, Michael J.; Wang, Xiu-Jie; Zhang, Xiuren

    2013-01-01

    miRNAs originate from primary transcripts (pri-miRNAs) with characteristic stem-loop structures. Accurate processing of pri-miRNAs is required for functional miRNAs. Here, using pri-miR166 family as a paradigm, we report the decisive role of pri-miRNA terminal loops in miRNA biogenesis. We found that multi-branched terminal loops in pri-miR166s substantially suppressed miR166 expression in vivo. Unlike canonical processing of pri-miRNAs, terminal-loop-branched (TLBed) pri-miRNAs can be processed by Dicer-like1 (DCL1) complexes bi-directionally: from base to loop and from loop to base, resulting in productive and abortive processing of miRNAs, respectively. In either case, DCL1 complexes canonically cut pri-miRNAs at a distance of 16-17 base pairs (bp) from a reference single-stranded loop region. DCL1 also adjusts processing sites toward an internal loop through its helicase domain. Thus, these results provide new insight into the poorly understood processing mechanism of pri-miRNAs with complicated secondary structures. PMID:23934148

  10. Neuro-classification of multi-type Landsat Thematic Mapper data

    NASA Technical Reports Server (NTRS)

    Zhuang, Xin; Engel, Bernard A.; Fernandez, R. N.; Johannsen, Chris J.

    1991-01-01

    Neural networks have been successful in image classification and have shown potential for classifying remotely sensed data. This paper presents classifications of multitype Landsat Thematic Mapper (TM) data using neural networks. The Landsat TM Image for March 23, 1987 with accompanying ground observation data for a study area In Miami County, Indiana, U.S.A. was utilized to assess recognition of crop residues. Principal components and spectral ratio transformations were performed on the TM data. In addition, a layer of the geographic information system (GIS) for the study site was incorporated to generate GIS-enhanced TM data. This paper discusses (1) the performance of neuro-classification on each type of data, (2) how neural networks recognized each type of data as a new image and (3) comparisons of the results for each type of data obtained using neural networks, maximum likelihood, and minimum distance classifiers.

  11. Direct Multitype Cardiac Indices Estimation via Joint Representation and Regression Learning.

    PubMed

    Xue, Wufeng; Islam, Ali; Bhaduri, Mousumi; Li, Shuo

    2017-05-26

    Cardiac indices estimation is of great importance during identification and diagnosis of cardiac disease in clinical routine. However, estimation of multitype cardiac indices with consistently reliable and high accuracy is still a great challenge due to the high variability of cardiac structures and complexity of temporal dynamics in cardiac MR sequences. While efforts have been devoted into cardiac volumes estimation through feature engineering followed by a independent regression model, these methods suffer from the vulnerable feature representation and incompatible regression model. In this paper, we propose a semi-automated method for multitype cardiac indices estimation. After manual labelling of two landmarks for ROI cropping, an integrated deep neural network Indices-Net is designed to jointly learn the representation and regression models. It comprises two tightly-coupled networks: a deep convolution autoencoder (DCAE) for cardiac image representation, and a multiple output convolution neural network (CNN) for indices regression. Joint learning of the two networks effectively enhances the expressiveness of image representation with respect to cardiac indices, and the compatibility between image representation and indices regression, thus leading to accurate and reliable estimations for all the cardiac indices. When applied with five-fold cross validation on MR images of 145 subjects, Indices-Net achieves consistently low estimation error for LV wall thicknesses (1.440.71mm) and areas of cavity and myocardium (204133mm2). It outperforms, with significant error reductions, segmentation method (55.1% and 17.4%) and two-phase direct volume-only methods (12.7% and 14.6%) for wall thicknesses and areas, respectively. These advantages endow the proposed method a great potential in clinical cardiac function assessment.

  12. A single carbon fiber microelectrode with branching carbon nanotubes for bioelectrochemical processes.

    PubMed

    Zhao, Xueyan; Lu, Xin; Tze, William T Y; Wang, Ping

    2010-06-15

    Carbon fiber electrodes are greatly promising for microelectronic applications including high performance biosensors, miniaturized transmitters, and energy storage and generation devices. For biosensor applications, one drawback of using carbon fiber microelectrodes, especially single fiber electrodes, is the weak electronic signals, a consequence of low surface area of fibers, which ultimately limit the sensitivity of the sensors. In this paper, we report a novel single fiber microelectrode with branched carbon nanotubes for enhanced sensing performance. The fiber microelectrode was prepared from carbonization of cellulose fibers. Upon introduction of carbon nanotubes, the carbon fibers exhibited a significant increase in the specific surface area from <10 to 36.4 m(2)/g (determined by the BET method). A single fiber electrode with such a hierarchical structure was examined for redox reactions of coenzyme NAD(H) which is useful to mediate the assays and transformations of a broad range of biochemicals. Experimental results showed that carbon nanotubes enhanced the redox reactions on surfaces of the electrode by reducing the oxidation potential of NAD(H) from 0.8 to 0.55 V. The single carbon fiber with branched nanotubes was also examined for the detection of glycerol, and the results showed linear responding signals in a concentration range of 40-250 microM. These results are comparable to the properties of fossil-based carbon materials, and thus our cellulose-based carbon electrodes provide a potentially sustainable alternative in bioelectrochemical applications.

  13. A Game-Theoretic Approach to Branching Time Abstract-Check-Refine Process

    NASA Technical Reports Server (NTRS)

    Wang, Yi; Tamai, Tetsuo

    2009-01-01

    Since the complexity of software systems continues to grow, most engineers face two serious problems: the state space explosion problem and the problem of how to debug systems. In this paper, we propose a game-theoretic approach to full branching time model checking on three-valued semantics. The three-valued models and logics provide successful abstraction that overcomes the state space explosion problem. The game style model checking that generates counter-examples can guide refinement or identify validated formulas, which solves the system debugging problem. Furthermore, output of our game style method will give significant information to engineers in detecting where errors have occurred and what the causes of the errors are.

  14. Damage detection in bridge structures under moving loads with phase trajectory change of multi-type vibration measurements

    NASA Astrophysics Data System (ADS)

    Zhang, Weiwei; Li, Jun; Hao, Hong; Ma, Hongwei

    2017-03-01

    This paper presents a non-model based damage detection approach for bridge structures under moving loads based on the phase trajectory change of multi-type vibration measurements. A brief theoretical background on the vibration of a simply-supported bridge with a crack under moving load is described. The phase trajectories of multi-type dynamic responses are obtained and a damage index is defined as the separated distance between the trajectories of undamaged and damaged structures to indicate the damage location. Numerical studies on a simply-supported beam structure are conducted to investigate the sensitivity and robustness of the proposed approach to accurately identify the damage location. Experimental studies demonstrate that the proposed approach can be used to successfully identify the shear connection failure in a composite bridge model subjected to moving loads.

  15. Assessing local population vulnerability to wind energy development with branching process models: an application to wind energy development

    USGS Publications Warehouse

    Erickson, Richard A.; Eager, Eric A.; Stanton, Jessica C.; Beston, Julie A.; Diffendorfer, James E.; Thogmartin, Wayne E.

    2015-01-01

    Quantifying the impact of anthropogenic development on local populations is important for conservation biology and wildlife management. However, these local populations are often subject to demographic stochasticity because of their small population size. Traditional modeling efforts such as population projection matrices do not consider this source of variation whereas individual-based models, which include demographic stochasticity, are computationally intense and lack analytical tractability. One compromise between approaches is branching process models because they accommodate demographic stochasticity and are easily calculated. These models are known within some sub-fields of probability and mathematical ecology but are not often applied in conservation biology and applied ecology. We applied branching process models to quantitatively compare and prioritize species locally vulnerable to the development of wind energy facilities. Specifically, we examined species vulnerability using branching process models for four representative species: A cave bat (a long-lived, low fecundity species), a tree bat (short-lived, moderate fecundity species), a grassland songbird (a short-lived, high fecundity species), and an eagle (a long-lived, slow maturation species). Wind turbine-induced mortality has been observed for all of these species types, raising conservation concerns. We simulated different mortality rates from wind farms while calculating local extinction probabilities. The longer-lived species types (e.g., cave bats and eagles) had much more pronounced transitions from low extinction risk to high extinction risk than short-lived species types (e.g., tree bats and grassland songbirds). High-offspring-producing species types had a much greater variability in baseline risk of extinction than the lower-offspring-producing species types. Long-lived species types may appear stable until a critical level of incidental mortality occurs. After this threshold, the risk of

  16. Water quality and hydrogeochemical processes in McDonalds Branch Basin, New Jersey pinelands, 1984-88. Water resources investigation

    SciTech Connect

    Johnsson, P.A.; Barringer, J.L.

    1993-12-31

    The report describes the spatial and temporal variability in the chemical constituents of surface and ground water in a small watershed in the Pinelands and discusses the complex hydrologic and geochemical processes thought to contribute to the variability associated with the freshwater wetlands within the basin. The report presents hydrologic measurements (precipitation amounts, stream stage and discharge, and water-table altitudes) and water-quality data (from analysis of samples of bulk and wet precipitation, surface water, and ground water) collected as part of a 1986-88 study by the USGS at McDonalds Branch basin.

  17. Color identification and fuzzy reasoning based monitoring and controlling of fermentation process of branched chain amino acid

    NASA Astrophysics Data System (ADS)

    Ma, Lei; Wang, Yizhong; Xu, Qingyang; Huang, Huafang; Zhang, Rui; Chen, Ning

    2009-11-01

    The main production method of branched chain amino acid (BCAA) is microbial fermentation. In this paper, to monitor and to control the fermentation process of BCAA, especially its logarithmic phase, parameters such as the color of fermentation broth, culture temperature, pH, revolution, dissolved oxygen, airflow rate, pressure, optical density, and residual glucose, are measured and/or controlled and/or adjusted. The color of fermentation broth is measured using the HIS color model and a BP neural network. The network's input is the histograms of hue H and saturation S, and output is the color description. Fermentation process parameters are adjusted using fuzzy reasoning, which is performed by inference rules. According to the practical situation of BCAA fermentation process, all parameters are divided into four grades, and different fuzzy rules are established.

  18. {sup 80}Se({gamma},n){sup 79}Se cross section and s-process branching at {sup 79}Se

    SciTech Connect

    Makinaga, A.; Utsunomiya, H.; Kaihori, T.; Yamagata, T.; Akimune, H.; Goriely, S.; Toyokawa, H.; Matsumoto, T.; Harano, H.; Harada, H.; Goko, S.; Kitatani, F.; Hara, K. Y.; Hohara, S.; Lui, Y.-W.

    2008-05-21

    Photoneutron cross sections were measured for {sup 80}Se near the neutron separation energy with laser Compton-backscattered {gamma}-ray beams at AIST. Neutron capture rates are evaluated for {sup 79}Se with the photoreaction data as experimental constraints on the El {gamma}-strength function, a key parameter in the Hauser-Feshbach statistical model calculation. Solving the set of differential equations under a single neutron exposure, we analyzed the solar abundance ratio of the weak components of {sup 80}Kr and {sup 82}Kr in terms of the s-process branching at {sup 79}Se. We discuss the region of temperature and neutron density allowed for the weak s-process nucleosynthesis.

  19. Provenance analysis and thermo-dynamic studies of multi-type Holocene duricrusts (1700 BC) in the Sua Salt Pan, NE Botswana

    NASA Astrophysics Data System (ADS)

    Dill, Harald G.; Dohrmann, R.; Kaufhold, S.; Techmer, A.

    2014-08-01

    Multi-type duricrusts, composed of silcretes, calcretes, halcretes and sulcretes developed during the Holocene at the northern rim of the Sua Salt Pan, NE Botswana. They were investigated for their light (quartz/chalcedony, feldspar, analcime, clinoptilolite, calcite, kaolinite/halloysite, illite-smectite mixed-layers, halite) and heavy minerals (baryte, clinozoisite-epidote s.s.s., amphibole, corundum, tourmaline, ilmenite, rutile, sphene, kyanite, andalusite, staurolite, garnet, zircon, apatite, monazite, cassiterite, garnet, biotite) using petrographic microscopy, X-ray fluorescence and diffraction analyses, radio-carbon dating, scanning electron microscopy equipped with an EDX-system, cation exchange capacity and infrared spectroscopy. Detrital minerals predominantly derived from the erosion of rocks belonging to the Archaean Basement Complex, the Stormberg Volcanites and the Kalahari sediments. Of particular interest to exploration geologists, geikielite-enriched ilmenite fragments are a hint to kimberlitic pipes. Biodetritus was derived from invertebrates and from vertebrates (fish bones?). A man-made impact on the heavy mineral suite has to be invoked from small fragments of cassiterite fragments that derived from processing of sulfidic and pegmatitic Sn-bearing ore. In the salt-pan-derived duricrusts mainly the aeolian and to a lesser degree fluvial inputs were responsible for the concentration of clasts in these multi-type duricrusts. Moreover, their variegated mineralogy enables us to constrain the physical-chemical regime, prevalently as to the pH and the chemical composition of the major constituents. All duricrusts developed in a self-sufficient chemically closed system where quartz and feldspar provided the elements Si, Na, K, Ca, and Ba to produce the encrustations. The spatial and temporal trend in the Sua Salt Pan rim encrustations may be described as follows: (1) sulcrete-silcretes, (2) silcretes with kaolinite-group minerals towards more recent

  20. Bidirectional processing of pri-miRNAs with branched terminal loops by Arabidopsis Dicer-like1.

    PubMed

    Zhu, Hongliang; Zhou, Yuyi; Castillo-González, Claudia; Lu, Amber; Ge, Chunxiao; Zhao, Ying-Tao; Duan, Liusheng; Li, Zhaohu; Axtell, Michael J; Wang, Xiu-Jie; Zhang, Xiuren

    2013-09-01

    MicroRNAs (miRNAs) originate from primary transcripts (pri-miRNAs) with characteristic stem-loop structures, and their accurate processing is required for the production of functional miRNAs. Here, using the pri-miR-166 family in Arabidopsis thaliana as a paradigm, we report the crucial role of pri-miRNA terminal loops in miRNA biogenesis. We found that multibranched terminal loops in pri-miR-166s substantially suppress miR-166 expression in vivo. Unlike canonical processing of pri-miRNAs, terminal loop-branched pri-miRNAs can be processed by Dicer-like 1 (DCL1) complexes bidirectionally from base to loop and from loop to base, resulting in productive and abortive processing of miRNAs, respectively. In both cases, DCL1 complexes canonically cut pri-miRNAs at a distance of 16-17 bp from a reference single-stranded loop region. DCL1 also adjusts processing sites toward an internal loop through its helicase domain. These results provide new insight into the poorly understood processing mechanism of pri-miRNAs with complex secondary structures.

  1. Development of Processable PMR-Type Polymides with Star-Branched Structures

    NASA Technical Reports Server (NTRS)

    Nguyen, Baochau N.; Eby, R. K.; Meador, Michael A.

    1999-01-01

    In the last two decades, high temperature polyimide matrix composites have found broad applications in aerospace structural components, due to their high specific modulus and high specific strength. As matrix resins, aromatic polyimides exhibit exceptional thermal stability and mechanical properties. However, their rodlike structures often result in poor solubility in most common organic solvents, as well as high melt temperature and melt viscosity, making them difficult to process. To overcome this difficulty, flexible linkages including O, SO2 or CH2 non coplanar biphenyl moieties, bulky lateral substituents, and crankshaft structures are often incorporated into the polymer backbones. Addition-curing of low molecular weight polyimides (resins) is another approach to improve processability. One of the most successfully developed materials has been PMR-15 (Polymerization of Monomer Reactants, molecular weight of 1500 g/mol), because of its good combination of thermal and mechanical properties and ease of processability. However, due to the high melt viscosity of PMR-type resins, use of more economical processing methods, such as resin transfer molding (RTM), is not possible. Recent research has focused on the incorporation of trifunctional monomers into addition-curing polyimides in an attempt to improve the processability of these polymers. The objective of this research is to use an aromatic triamine, 1,3,5 tris (4-aminophenoxy) benzene, to prepare new resin systems with starbranched structures. The glass transition temperatures (Tg's) and thermal oxidative stability TOS) of these polymers are compared to their linear counterparts and PMR-15.

  2. Multitype Activity Coexistence in an Inertial Two-Neuron System with Multiple Delays

    NASA Astrophysics Data System (ADS)

    Song, Zigen; Xu, Jian; Zhen, Bin

    2015-12-01

    In this paper, an inertial two-neuron system with multiple delays is analyzed to exhibit the effect of time delays on system dynamics. The parameter region with multiple equilibria is obtained employing the pitchfork bifurcation of trivial equilibrium. The stability analysis illustrates that two nontrivial equilibria are both stable for any delays. It implies that the neural system exhibits a stability coexistence of two resting states. Further, due to the existence of multiple delays, the neural system has a periodic activity around the trivial equilibrium via Hopf bifurcation. Finally, numerical simulations are employed to illustrate many richness coexistence for multitype activity patterns. Employing the period-adding route and fold bifurcation of periodic orbit, the neural system may have multistability coexistence of two resting states, two ASP-3s (anti-symmetric periodic activity with period three), one SSP-1 (self-symmetric periodic activity with period one), and one quasi-periodic spiking. Additionally, with increasing delay, quasi-periodic spiking evolves into chaos behavior.

  3. Consumer health information partnerships: the health science library and multitype library system.

    PubMed Central

    Hollander, S

    1996-01-01

    The University of Illinois Library of the Health Sciences at Rockford (LHS-Rockford) long has honored a commitment to serving the health information needs of the greater Rockford community. Utilization data collected over the past five years indicate that approximately 50% of reference transactions involve persons not affiliated with the university. In early 1994, LHS-Rockford submitted a proposal to the Northern Illinois Library System (NILS), a multitype system spanning twelve counties in northwestern Illinois, asking to serve as a resource library for improving medical and health information services provided by the 138 NILS member libraries. The NILS funded this pilot project as part of an effort to implement a new strategic plan, which encouraged member libraries to form networks to provide reference back-up service. LHS-Rockford acquired InfoTrac's Health Reference Center, a consumer health information database, and set up a dedicated workstation near the information and circulation desk. Referral guidelines were established and the project was promoted among NILS member libraries. Activities were documented in order to track project success in terms of referrals and outcomes. The demonstration project was very successful, and it proves public consumers seeking health information can benefit greatly from this type of cooperative arrangement. PMID:8826632

  4. An analysis of multi-type relational interactions in FMA using graph motifs with disjointness constraints.

    PubMed

    Zhang, Guo-Qiang; Luo, Lingyun; Ogbuji, Chime; Joslyn, Cliff; Mejino, Jose; Sahoo, Satya S

    2012-01-01

    The interaction of multiple types of relationships among anatomical classes in the Foundational Model of Anatomy (FMA) can provide inferred information valuable for quality assurance. This paper introduces a method called Motif Checking (MOCH) to study the effects of such multi-relation type interactions for detecting logical inconsistencies as well as other anomalies represented by the motifs. MOCH represents patterns of multi-type interaction as small labeled (with multiple types of edges) sub-graph motifs, whose nodes represent class variables, and labeled edges represent relational types. By representing FMA as an RDF graph and motifs as SPARQL queries, fragments of FMA are automatically obtained as auditing candidates. Leveraging the scalability and reconfigurability of Semantic Web Technology, we performed exhaustive analyses of a variety of labeled sub-graph motifs. The quality assurance feature of MOCH comes from the distinct use of a subset of the edges of the graph motifs as constraints for disjointness, whereby bringing in rule-based flavor to the approach as well. With possible disjointness implied by antonyms, we performed manual inspection of the resulting FMA fragments and tracked down sources of abnormal inferred conclusions (logical inconsistencies), which are amendable for programmatic revision of the FMA. Our results demonstrate that MOCH provides a unique source of valuable information for quality assurance. Since our approach is general, it is applicable to any ontological system with an OWL representation.

  5. HEMODOSE: A Biodosimetry Tool Based on Multi-type Blood Cell Counts

    PubMed Central

    Hu, Shaowen; Blakely, William F.; Cucinotta, Francis A.

    2015-01-01

    Abstract Peripheral blood cell counts are important biomarkers of radiation exposure. In this work, a simplified compartmental modeling approach is applied to simulate the perturbation of the hematopoiesis system in humans after radiation exposure, and HemoDose software is reported to estimate individuals’ absorbed doses based on multi-type blood cell counts. Testing with patient data in some historical accidents indicates that either single or serial granulocyte, lymphocyte, leukocyte, and platelet counts after exposure can be robust indicators of the absorbed doses. In addition, such correlation exists not only in the early time window (1 or 2 d) but also in the late phase (up to 4 wk) after exposure, when the four types of cell counts are combined for analysis. These demonstrate the capability of HemoDose as a rapid point-of-care diagnostic or centralized high-throughput assay system for personnel exposed to unintended high doses of radiation, especially in large-scale nuclear/radiological disaster scenarios involving mass casualties. PMID:26011498

  6. An Analysis of Multi-type Relational Interactions in FMA Using Graph Motifs with Disjointness Constraints

    PubMed Central

    Zhang, Guo-Qiang; Luo, Lingyun; Ogbuji, Chime; Joslyn, Cliff; Mejino, Jose; Sahoo, Satya S

    2012-01-01

    The interaction of multiple types of relationships among anatomical classes in the Foundational Model of Anatomy (FMA) can provide inferred information valuable for quality assurance. This paper introduces a method called Motif Checking (MOCH) to study the effects of such multi-relation type interactions for detecting logical inconsistencies as well as other anomalies represented by the motifs. MOCH represents patterns of multi-type interaction as small labeled (with multiple types of edges) sub-graph motifs, whose nodes represent class variables, and labeled edges represent relational types. By representing FMA as an RDF graph and motifs as SPARQL queries, fragments of FMA are automatically obtained as auditing candidates. Leveraging the scalability and reconfigurability of Semantic Web Technology, we performed exhaustive analyses of a variety of labeled sub-graph motifs. The quality assurance feature of MOCH comes from the distinct use of a subset of the edges of the graph motifs as constraints for disjointness, whereby bringing in rule-based flavor to the approach as well. With possible disjointness implied by antonyms, we performed manual inspection of the resulting FMA fragments and tracked down sources of abnormal inferred conclusions (logical inconsistencies), which are amendable for programmatic revision of the FMA. Our results demonstrate that MOCH provides a unique source of valuable information for quality assurance. Since our approach is general, it is applicable to any ontological system with an OWL representation. PMID:23304382

  7. A fully Bayesian latent variable model for integrative clustering analysis of multi-type omics data.

    PubMed

    Mo, Qianxing; Shen, Ronglai; Guo, Cui; Vannucci, Marina; Chan, Keith S; Hilsenbeck, Susan G

    2017-05-24

    Identification of clinically relevant tumor subtypes and omics signatures is an important task in cancer translational research for precision medicine. Large-scale genomic profiling studies such as The Cancer Genome Atlas (TCGA) Research Network have generated vast amounts of genomic, transcriptomic, epigenomic, and proteomic data. While these studies have provided great resources for researchers to discover clinically relevant tumor subtypes and driver molecular alterations, there are few computationally efficient methods and tools for integrative clustering analysis of these multi-type omics data. Therefore, the aim of this article is to develop a fully Bayesian latent variable method (called iClusterBayes) that can jointly model omics data of continuous and discrete data types for identification of tumor subtypes and relevant omics features. Specifically, the proposed method uses a few latent variables to capture the inherent structure of multiple omics data sets to achieve joint dimension reduction. As a result, the tumor samples can be clustered in the latent variable space and relevant omics features that drive the sample clustering are identified through Bayesian variable selection. This method significantly improve on the existing integrative clustering method iClusterPlus in terms of statistical inference and computational speed. By analyzing TCGA and simulated data sets, we demonstrate the excellent performance of the proposed method in revealing clinically meaningful tumor subtypes and driver omics features. © The Author 2017. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  8. Photodisintegration of {sup 80}Se: Implications for the s-process branching at {sup 79}Se

    SciTech Connect

    Makinaga, A.; Utsunomiya, H.; Kaihori, T.; Akimune, H.; Yamagata, T.; Goriely, S.; Goko, S.; Harada, H.; Kitatani, F.; Hara, Y. K.; Toyokawa, H.; Matsumoto, T.; Harano, H.; Hohara, S.; Lui, Y.-W.

    2009-02-15

    Photoneutron cross sections were measured for {sup 80}Se immediately above the neutron separation energy with quasimonochromatic {gamma}-ray beams to experimentally constrain the E1 {gamma} strength function for {sup 80}Se. Two sets of the {gamma} strength function and the level density that equally meet the experimental constraint predict largely different neutron capture cross sections for {sup 79}Se. Based on the Maxwellian-averaged cross sections of the latest compilation complemented with the predicted cross sections for {sup 79}Se, we calculated {sigma}N values of the main s-process component using a phenomenological model and deduced empirical abundances of the weak s-process component. An attempt is made of considering the implications of the abundance ratios of {sup 80}Kr and {sup 82}Kr within the framework of phenomenological models for the weak s process.

  9. Branching Ratios for Secondary Processes of Water Ions Induced by Proton Beams in Radiation Therapy of Cancer

    NASA Astrophysics Data System (ADS)

    Pichl, L.; Kimura, M.; Li, Yan; Buenker, R. J.

    2004-08-01

    New results are reported that can improve proton beam instrumentation in radiation medicine and cancer therapy. The destructive effects of proton beams are primarily based on direct collision ionization and radiolysis of water. Resulting fragments subsequently alter the cell cycle by damaging the DNA with different efficiency. We have therefore computed the water ion and hydronium potential energy surfaces and obtained branching ratios for proton-water processes that further involve low energy electrons, OH radicals, and metastable O/sup +/ ions. In addition, all related data available in the literature are shortly summarized and reviewed. State-selective excitation and electron capture cross sections reported in this paper allow for solving the rate equations of the ion production cascade.

  10. Processing of DNA structures via DNA unwinding and branch migration by the S. cerevisiae Mph1 protein.

    PubMed

    Zheng, Xiao-Feng; Prakash, Rohit; Saro, Dorina; Longerich, Simonne; Niu, Hengyao; Sung, Patrick

    2011-10-10

    The budding yeast Mph1 protein, the putative ortholog of human FANCM, possesses a 3' to 5' DNA helicase activity and is capable of disrupting the D-loop structure to suppress chromosome arm crossovers in mitotic homologous recombination. Similar to FANCM, genetic studies have implicated Mph1 in DNA replication fork repair. Consistent with this genetic finding, we show here that Mph1 is able to mediate replication fork reversal, and to process the Holliday junction via DNA branch migration. Moreover, Mph1 unwinds 3' and 5' DNA Flap structures that bear key features of the D-loop. These biochemical results not only provide validation for a role of Mph1 in the repair of damaged replication forks, but they also offer mechanistic insights as to its ability to efficiently disrupt the D-loop intermediate.

  11. Undersampled critical branching processes on small-world and random networks fail to reproduce the statistics of spike avalanches.

    PubMed

    Ribeiro, Tiago L; Ribeiro, Sidarta; Belchior, Hindiael; Caixeta, Fábio; Copelli, Mauro

    2014-01-01

    The power-law size distributions obtained experimentally for neuronal avalanches are an important evidence of criticality in the brain. This evidence is supported by the fact that a critical branching process exhibits the same exponent [Formula: see text]. Models at criticality have been employed to mimic avalanche propagation and explain the statistics observed experimentally. However, a crucial aspect of neuronal recordings has been almost completely neglected in the models: undersampling. While in a typical multielectrode array hundreds of neurons are recorded, in the same area of neuronal tissue tens of thousands of neurons can be found. Here we investigate the consequences of undersampling in models with three different topologies (two-dimensional, small-world and random network) and three different dynamical regimes (subcritical, critical and supercritical). We found that undersampling modifies avalanche size distributions, extinguishing the power laws observed in critical systems. Distributions from subcritical systems are also modified, but the shape of the undersampled distributions is more similar to that of a fully sampled system. Undersampled supercritical systems can recover the general characteristics of the fully sampled version, provided that enough neurons are measured. Undersampling in two-dimensional and small-world networks leads to similar effects, while the random network is insensitive to sampling density due to the lack of a well-defined neighborhood. We conjecture that neuronal avalanches recorded from local field potentials avoid undersampling effects due to the nature of this signal, but the same does not hold for spike avalanches. We conclude that undersampled branching-process-like models in these topologies fail to reproduce the statistics of spike avalanches.

  12. Undersampled Critical Branching Processes on Small-World and Random Networks Fail to Reproduce the Statistics of Spike Avalanches

    PubMed Central

    Ribeiro, Tiago L.; Ribeiro, Sidarta; Belchior, Hindiael; Caixeta, Fábio; Copelli, Mauro

    2014-01-01

    The power-law size distributions obtained experimentally for neuronal avalanches are an important evidence of criticality in the brain. This evidence is supported by the fact that a critical branching process exhibits the same exponent . Models at criticality have been employed to mimic avalanche propagation and explain the statistics observed experimentally. However, a crucial aspect of neuronal recordings has been almost completely neglected in the models: undersampling. While in a typical multielectrode array hundreds of neurons are recorded, in the same area of neuronal tissue tens of thousands of neurons can be found. Here we investigate the consequences of undersampling in models with three different topologies (two-dimensional, small-world and random network) and three different dynamical regimes (subcritical, critical and supercritical). We found that undersampling modifies avalanche size distributions, extinguishing the power laws observed in critical systems. Distributions from subcritical systems are also modified, but the shape of the undersampled distributions is more similar to that of a fully sampled system. Undersampled supercritical systems can recover the general characteristics of the fully sampled version, provided that enough neurons are measured. Undersampling in two-dimensional and small-world networks leads to similar effects, while the random network is insensitive to sampling density due to the lack of a well-defined neighborhood. We conjecture that neuronal avalanches recorded from local field potentials avoid undersampling effects due to the nature of this signal, but the same does not hold for spike avalanches. We conclude that undersampled branching-process-like models in these topologies fail to reproduce the statistics of spike avalanches. PMID:24751599

  13. A branching process model for the analysis of abortive colony size distributions in carbon ion-irradiated normal human fibroblasts.

    PubMed

    Sakashita, Tetsuya; Hamada, Nobuyuki; Kawaguchi, Isao; Hara, Takamitsu; Kobayashi, Yasuhiko; Saito, Kimiaki

    2014-05-01

    A single cell can form a colony, and ionizing irradiation has long been known to reduce such a cellular clonogenic potential. Analysis of abortive colonies unable to continue to grow should provide important information on the reproductive cell death (RCD) following irradiation. Our previous analysis with a branching process model showed that the RCD in normal human fibroblasts can persist over 16 generations following irradiation with low linear energy transfer (LET) γ-rays. Here we further set out to evaluate the RCD persistency in abortive colonies arising from normal human fibroblasts exposed to high-LET carbon ions (18.3 MeV/u, 108 keV/µm). We found that the abortive colony size distribution determined by biological experiments follows a linear relationship on the log-log plot, and that the Monte Carlo simulation using the RCD probability estimated from such a linear relationship well simulates the experimentally determined surviving fraction and the relative biological effectiveness (RBE). We identified the short-term phase and long-term phase for the persistent RCD following carbon-ion irradiation, which were similar to those previously identified following γ-irradiation. Taken together, our results suggest that subsequent secondary or tertiary colony formation would be invaluable for understanding the long-lasting RCD. All together, our framework for analysis with a branching process model and a colony formation assay is applicable to determination of cellular responses to low- and high-LET radiation, and suggests that the long-lasting RCD is a pivotal determinant of the surviving fraction and the RBE.

  14. A branching process model for the analysis of abortive colony size distributions in carbon ion-irradiated normal human fibroblasts

    PubMed Central

    Sakashita, Tetsuya; Hamada, Nobuyuki; Kawaguchi, Isao; Hara, Takamitsu; Kobayashi, Yasuhiko; Saito, Kimiaki

    2014-01-01

    A single cell can form a colony, and ionizing irradiation has long been known to reduce such a cellular clonogenic potential. Analysis of abortive colonies unable to continue to grow should provide important information on the reproductive cell death (RCD) following irradiation. Our previous analysis with a branching process model showed that the RCD in normal human fibroblasts can persist over 16 generations following irradiation with low linear energy transfer (LET) γ-rays. Here we further set out to evaluate the RCD persistency in abortive colonies arising from normal human fibroblasts exposed to high-LET carbon ions (18.3 MeV/u, 108 keV/µm). We found that the abortive colony size distribution determined by biological experiments follows a linear relationship on the log–log plot, and that the Monte Carlo simulation using the RCD probability estimated from such a linear relationship well simulates the experimentally determined surviving fraction and the relative biological effectiveness (RBE). We identified the short-term phase and long-term phase for the persistent RCD following carbon-ion irradiation, which were similar to those previously identified following γ-irradiation. Taken together, our results suggest that subsequent secondary or tertiary colony formation would be invaluable for understanding the long-lasting RCD. All together, our framework for analysis with a branching process model and a colony formation assay is applicable to determination of cellular responses to low- and high-LET radiation, and suggests that the long-lasting RCD is a pivotal determinant of the surviving fraction and the RBE. PMID:24501383

  15. Origin and diversification of living cycads: a cautionary tale on the impact of the branching process prior in Bayesian molecular dating.

    PubMed

    Condamine, Fabien L; Nagalingum, Nathalie S; Marshall, Charles R; Morlon, Hélène

    2015-04-17

    Bayesian relaxed-clock dating has significantly influenced our understanding of the timeline of biotic evolution. This approach requires the use of priors on the branching process, yet little is known about their impact on divergence time estimates. We investigated the effect of branching priors using the iconic cycads. We conducted phylogenetic estimations for 237 cycad species using three genes and two calibration strategies incorporating up to six fossil constraints to (i) test the impact of two different branching process priors on age estimates, (ii) assess which branching prior better fits the data, (iii) investigate branching prior impacts on diversification analyses, and (iv) provide insights into the diversification history of cycads. Using Bayes factors, we compared divergence time estimates and the inferred dynamics of diversification when using Yule versus birth-death priors. Bayes factors were calculated with marginal likelihood estimated with stepping-stone sampling. We found striking differences in age estimates and diversification dynamics depending on prior choice. Dating with the Yule prior suggested that extant cycad genera diversified in the Paleogene and with two diversification rate shifts. In contrast, dating with the birth-death prior yielded Neogene diversifications, and four rate shifts, one for each of the four richest genera. Nonetheless, dating with the two priors provided similar age estimates for the divergence of cycads from Ginkgo (Carboniferous) and their crown age (Permian). Of these, Bayes factors clearly supported the birth-death prior. These results suggest the choice of the branching process prior can have a drastic influence on our understanding of evolutionary radiations. Therefore, all dating analyses must involve a model selection process using Bayes factors to select between a Yule or birth-death prior, in particular on ancient clades with a potential pattern of high extinction. We also provide new insights into the

  16. Photodisintegration of 80Se and its implications for s-process branching

    SciTech Connect

    Makinaga, A.; Utsunomiya, H.; Goko, S.; Kaihori, T.; Houhara, S.; Goriely, S.; Toyokawa, H.; Harano, H.; Matsumoto, T.; Harada, H.; Kitatani, F.; Hara, K. Y.; Lui, Y.-W.

    2007-02-26

    Photodisintegration cross sections were measured for 80Se with laser Compton scattering {gamma} beams at E{gamma}=9.98-11.80 MeV near the neutron separation energy. The stellar neutron capture rate for 80Se was evaluated by using the photodisintegration data as constraints on the E1 {gamma} strength function for 80Se within the framework of the Hauser-Feshbach statistical model. It was found that the rate at 30 keV is 0.7-1.1 times that of Bao and Kaeppeler. s-process temperatures deduced from the empirical solar abundances of the s-only nuclei 79Se and 80Kr with this neutron capture rate are 17-25 keV in the neutron density rage of (0.8-1.9)x103/cm3.

  17. Neutron Capture Cross Sections of the s-Process Branching Points 147Pm, 171Tm, and 204Tl

    NASA Astrophysics Data System (ADS)

    Guerrero, Carlos; Domingo-Pardo, Cesar; Lerendegui-Marco, Jorge; Casanovas, Adria; Cortes-Giraldo, Miguel A.; Dressler, Rugard; Halfon, Shlomi; Heinitz, Stephan; Kivel, Niko; Köster, Ulli; Paul, Michael; Quesada-Molina, Jose Manuel; Schumann, Dorothea; Tarifeño-Saldivia, Ariel; Tessler, Moshe; Weissman, Leo

    The neutron capture cross section of several key unstable isotopes acting as branching points in the s-process are crucial for stellar nucleosynthesis studies, but they are very challenging to measure due to the difficult production of sufficient sample material, the high activity of the resulting samples, and the actual (n, γ) measurement, for which high neutron fluxes and effective background rejection capabilities are required. As part of a new program to measure some of these important branching points, radioactive targets of 147Pm, 171Tm, and 204Tl have been produced by irradiation of stable isotopes (146Nd, 170Er, and 203Tl) at the Institut Laue-Langevin (ILL) high flux reactor. After breeding in the reactor and a certain cooling period, the resulting mixed 204Tl/203Tl sample was used directly while 147Pm and 171Tm were radiochemically separated in non-carrier-added quality at the Paul Scherrer Institut (PSI), then prepared as targets. A set of theses samples has been used for time-of-flight measurements at the CERN n_TOF facility using the 19 and 185 m beam lines, during 2014 and 2015. The capture cascades were detected with a set of four C6D6 scintillators, allowing to observe the associated neutron capture resonances. The results presented in this work are the first ever determination of the resonance capture cross sections of 147Pm, 171Tm, and 204Tl. Activation experiments on the same 147Pm and 171Tm targets with a high-intensity quasi-Maxwellian flux of neutrons have been performed using the SARAF accelerator and the Liquid-Lithium Target (LiLiT) in order to extract the corresponding Maxwellian Average Cross Section (MACS). The experimental setups are here described together with the first, preliminary results of the n_TOF measurement.

  18. Charged lepton flavor violating processes and scalar leptoquark decay branching ratios in the colored Zee-Babu model

    NASA Astrophysics Data System (ADS)

    Chang, We-Fu; Liou, Siao-Cing; Wong, Chi-Fong; Xu, Fanrong

    2016-10-01

    We consider a neutrino mass generating model which employs a scalar leptoquark, Δ, and a scalar diquark, S. The new scalars Δ and S carry the standard model SU(3) c × SU(2) L × U(1) Y quantum numbers (3 , 1 , -1 /3) and (6 , 1 , -2 /3), respectively. The neutrino masses are generated at the two-loop level, as in the Zee-Babu model [1, 2], and Δ /S plays the role of the doubly/singly charged scalar in the Zee-Babu model. With a moderate working assumption that the magnitudes of the six Yukawa couplings between S and the down-type quarks are of the same order, strong connections are found between the neutrino masses and the charged lepton flavor violating processes. In particular, we study Zto overline{l}{l}^' } , and l→ l 'γ and find that some portions of the parameter space of this model are within the reach of the planned charged lepton flavor violating experiments. Interesting lower bounds are predicted that B(Zto overline{l}{l}^')≳ 1{0}^{-16} - 1{0}^{-14}(1{0}^{-14}) × {(1 TeV \\cdotp {m}_S/7{m}{^{Δ}}^2)}^2 and B( l → l' γ) ≳ 10- 17 - 10- 16(10- 18 - 10- 16) × (1 TeV · m S /7 m Δ 2 )2 for neutrino masses being the normal (inverted) hierarchical pattern. The type of neutrino mass hierarchy could also be determined by measuring the charged lepton flavor violating double ratios. Moreover, definite leptoquark decay branching ratios are predicted when there is no Yukawa interaction between the right-handed fermions and Δ (the branching fraction of Δ to a charged lepton and a quark is 50%), which could help refine the collider search limit on the scalar leptoquark mass.

  19. SiC particles from asymptotic giant branch stars - Mg burning and the s-process

    NASA Technical Reports Server (NTRS)

    Brown, Lawrence E.; Clayton, Donald D.

    1992-01-01

    The question of whether isotopically anomalous SiC particles found in meteorites originate in AGB stars is addressed. It is shown that if the peak helium shell flash temperatures of massive (6-9 solar masses) stars are about 10 percent larger than they are normally assumed to be, alpha particle reactions with the magnesium will become significant. Then the (Mg-29)(alpha, n)Si-29 reaction produces a large excess of Si-29. With a light element nuclear reaction network, the evolution of the silicon isotopic composition during AGB evolution is calculated. It is found that the experimentally determined correlation between excess Si-29 and excess Si-30 in SiC particles from carbonaceous chondrites can indeed be naturally produced in this way. It is suggested that if the large isotopically anomalous SiC particles carrying nearly pure-process krypton and xenon do indeed originate in AGB stars, those stars were massive and had peak shell flash temperatures near 450 KM.

  20. Modeling the spread of infectious disease using genetic information within a marked branching process.

    PubMed

    Leman, Scotland C; Levy, Foster; Walker, Elaine S

    2009-12-20

    Accurate assessment of disease dynamics requires a quantification of many unknown parameters governing disease transmission processes. While infection control strategies within hospital settings are stringent, some disease will be propagated due to human interactions (patient-to-patient or patient-to-caregiver-to-patient). In order to understand infectious transmission rates within the hospital, it is necessary to isolate the amount of disease that is endemic to the outside environment. While discerning the origins of disease is difficult when using ordinary spatio-temporal data (locations and time of disease detection), genotypes that are common to pathogens, with common sources, aid in distinguishing nosocomial infections from independent arrivals of the disease. The purpose of this study was to demonstrate a Bayesian modeling procedure for identifying nosocomial infections, and quantify the rate of these transmissions. We will demonstrate our method using a 10-year history of Morexella catarhallis. Results will show the degree to which pathogen-specific, genotypic information impacts inferences about the nosocomial rate of infection.

  1. Stochastic modeling of stress erythropoiesis using a two-type age-dependent branching process with immigration.

    PubMed

    Hyrien, O; Peslak, S A; Yanev, N M; Palis, J

    2015-06-01

    The erythroid lineage is a particularly sensitive target of radiation injury. We model the dynamics of immature (BFU-E) and mature (CFU-E) erythroid progenitors, which have markedly different kinetics of recovery, following sublethal total body irradiation using a two-type reducible age-dependent branching process with immigration. Properties of the expectation and variance of the frequencies of both types of progenitors are presented. Their explicit expressions are derived when the process is Markovian, and their asymptotic behavior is identified in the age-dependent (non-Markovian) case. Analysis of experimental data on the kinetics of BFU-E and CFU-E reveals that the probability of self-renewal increases transiently for both cell types following sublethal irradiation. In addition, the probability of self-renewal increased more for CFU-E than for BFU-E. The strategy adopted by the erythroid lineage ensures replenishment of the BFU-E compartment while optimizing the rate of CFU-E recovery. Finally, our analysis also indicates that radiation exposure causes a delay in BFU-E recovery consistent with injury to the hematopoietic stem/progenitor cell compartment that give rise to BFU-E. Erythroid progenitor self-renewal is thus an integral component of the recovery of the erythron in response to stress.

  2. An Analysis of Multi-type Relational Interactions in FMA Using Graph Motifs with Disjointness Constraints

    SciTech Connect

    Zhang, Guo Qiang; Luo, Lingyun; Ogbuji, Chime; Joslyn, Cliff A.; Mejino, Jose; Sahoo, Satya S.

    2012-11-24

    The interaction of multiple types of relationships among anatomical classes in the Foundational Model of Anatomy (FMA) can provide inferred information valuable for quality assurance. This paper introduces a method called Motif Checking (MOCH) to study the effects of such multi-relation type interactions. MOCH represents patterns of multitype interaction as small labeled sub-graph motifs, whose nodes represent class variables, and labeled edges represent relational types. By representing FMA as an RDF graph and motifs as SPARQL queries, fragments of FMA are automatically obtained as auditing candidates. Leveraging the scalability and reconfigurability of Semantic Web Technology (OWL, RDF and SPARQL) and Virtuoso, we performed exhaustive analyses of three 2-node motifs, resulting in 638 matching FMA configurations; twelve 3-node motifs, resulting in 202,960 configurations. Using the Principal Ideal Explorer (PIE) methodology as an extension of MOCH, we were able to identify 755 root nodes with 4,100 respective descendants with opposing antonyms in their class names for arbitrary-length motifs. With possible disjointness implied by antonyms, we performed manual inspection of a subset of the resulting FMA fragments and tracked down a source of abnormal inferred conclusions (captured by the motifs), coming from a gender-neutral class being modeled as a part of gender-specific class, such as “Urinary system” is a part of “Female human body.” Our results demonstrate that MOCH and PIE provide a unique source of valuable information for quality assurance. Since our approach is general, it is applicable to any ontological system with an OWL representation.

  3. Materials Test Branch

    NASA Technical Reports Server (NTRS)

    Gordon, Gail

    2012-01-01

    The Materials Test Branch resides at Marshall Space Flight Center's Materials and Processing laboratory and has a long history of supporting NASA programs from Mercury to the recently retired Space Shuttle. The Materials Test Branch supports its customers by supplying materials testing expertise in a wide range of applications. The Materials Test Branch is divided into three Teams, The Chemistry Team, The Tribology Team and the Mechanical Test Team. Our mission and goal is to provide world-class engineering excellence in materials testing with a special emphasis on customer service.

  4. Long chain branching as an innovative up-cycling process of polypropylene post-consumer waste - Possibilities and limitations.

    PubMed

    Kamleitner, Florian; Duscher, Bernadette; Koch, Thomas; Knaus, Simone; Archodoulaki, Vasiliki-Maria

    2017-07-20

    Long chain branching (LCB) was used the first time as an innovative tool for value adding to PP from household post-consumer waste. Due to the highly improved melt properties, the possible application profile is extended and not only a "re-cycling" process, even a real "up-cycling" is presented. The used PP was collected from commingled household polyolefin waste, which contained different types of PP and macromolecular impurities such as 10% of polyethylene with high density (PE-HD). In addition, a single PP waste fraction from cleaned beverage and yoghurt cups was manually sorted. The up-cycled PP from single polymer waste, as well as the post-consumer blend, showed pronounced strain hardening and increased melt strength, which was comparable to LCB-PP prepared from virgin PP. However, the up-cycled post-consumer blend showed weaker mechanical performance especially low elongation at break due to PE-HD. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. Expectation-maximization algorithm for determining natural selection of Y-linked genes through two-sex branching processes.

    PubMed

    González, M; Gutiérrez, C; Martínez, R

    2012-09-01

    A two-dimensional bisexual branching process has recently been presented for the analysis of the generation-to-generation evolution of the number of carriers of a Y-linked gene. In this model, preference of females for males with a specific genetic characteristic is assumed to be determined by an allele of the gene. It has been shown that the behavior of this kind of Y-linked gene is strongly related to the reproduction law of each genotype. In practice, the corresponding offspring distributions are usually unknown, and it is necessary to develop their estimation theory in order to determine the natural selection of the gene. Here we deal with the estimation problem for the offspring distribution of each genotype of a Y-linked gene when the only observable data are each generation's total numbers of males of each genotype and of females. We set out the problem in a non parametric framework and obtain the maximum likelihood estimators of the offspring distributions using an expectation-maximization algorithm. From these estimators, we also derive the estimators for the reproduction mean of each genotype and forecast the distribution of the future population sizes. Finally, we check the accuracy of the algorithm by means of a simulation study.

  6. Grain size associations of branched tetraether lipids in soils and riverbank sediments: influence of hydrodynamic sorting processes

    NASA Astrophysics Data System (ADS)

    Peterse, Francien; Eglinton, Timothy I.

    2017-06-01

    We analyzed the abundance and distribution of branched glycerol dialkyl glycerol tetraethers (brGDGTs) in grain size fractions of 7 globally distributed river flank sediments and catchment soils in order to determine if and how the initial soil-brGDGT signature is influenced by hydrodynamic sorting upon entering a river and during subsequent transport from land to sea. BrGDGTs are hypothesized to form associations with high-surface-area fine-grained minerals in soils. Such associations, if maintained during transport, may impart resistance to degradation and promote downstream transport, reducing potential interferences by aquatic brGDGTs. We find that brGDGTs are indeed primarily associated with organic carbon (OC) bound to the clay-silt fraction (<63μm) in both soils and river sediments, and that these associations appear to be maintained during river transport. However, the relative distribution of individual brGDGTs among size fractions is relatively uniform, suggesting that brGDGTs are well mixed in river sediments and that OC-mineral associations are continuously renewed. Consequently, the brGDGT signature finally stored in continental margin sediments appears insensitive to differential particle transport processes. Nevertheless, the lower (upstream) temperature signal generally reflected by brGDGTs in river sediments may also be explained by a contribution of in situ produced brGDGTs leading to an underestimation of reconstructed air temperatures.

  7. Hydrogeochemical processes controlling subsurface transport from an upper subcatchment of Walker Branch watershed during storm events. 1. Hydrologic transport processes

    NASA Astrophysics Data System (ADS)

    Wilson, G. V.; Jardine, P. M.; Luxmoore, R. J.; Zelazny, L. W.; Lietzke, D. A.; Todd, D. E.

    1991-03-01

    Concerns over the effects of acid rain have stimulated numerous hydrometric and geochemical studies on forested watersheds with an emphasis on stream water chemistry. However, integrated studies are seriously lacking, and inferences of soil hydrogeochemical processes from periodic stream water chemistry may be grossly misleading. A small forested subcatchment was intensively instrumented for hydrologic and chemical analyses to improve our understanding of the processes that control subsurface transport of solutes. The timing and volume of subsurface flows were found to be highly dependent upon soil hydromorphologic properties. Development of perched water tables was the predominate mechanism of subsurface flow through the lower layers during moderate to high flow events. Perching of water was insignificant during low flow events and only partially responsible for lateral flow through the upper soil layers during moderate events. The importance of nonequilibrium conditions during even low flow events was illustrated by the occurrence of saturated flow through unsaturated (matric potentials < - 2kPa soil. The initial subsurface flow response of a moderate and high flow event was predominately (> 70%) new water that bypassed the soil matrix. As flows continued the percentage of old water increased. Intermittent rainfall during the high flow event caused multiple peaks in subsurface flow with subtle increases in perching. These hydrograph peaks were associated with decreases in the percentage of old water. This suggests an increase in the portion of infiltrating water that bypasses soil matrix water via macropores causing increases in subsurface flows with limited growth of perched water tables. The persistence of perched water tables as flow decreased was consistently observed. Decreases in solute concentrations causing decreases in conductivity of pores was inferred as one mechanism for this.

  8. Nonlinear complexity of random visibility graph and Lempel-Ziv on multitype range-intensity interacting financial dynamics

    NASA Astrophysics Data System (ADS)

    Zhang, Yali; Wang, Jun

    2017-09-01

    In an attempt to investigate the nonlinear complex evolution of financial dynamics, a new financial price model - the multitype range-intensity contact (MRIC) financial model, is developed based on the multitype range-intensity interacting contact system, in which the interaction and transmission of different types of investment attitudes in a stock market are simulated by viruses spreading. Two new random visibility graph (VG) based analyses and Lempel-Ziv complexity (LZC) are applied to study the complex behaviors of return time series and the corresponding random sorted series. The VG method is the complex network theory, and the LZC is a non-parametric measure of complexity reflecting the rate of new pattern generation of a series. In this work, the real stock market indices are considered to be comparatively studied with the simulation data of the proposed model. Further, the numerical empirical study shows the similar complexity behaviors between the model and the real markets, the research confirms that the financial model is reasonable to some extent.

  9. Barium isotopic composition of mainstream silicon carbides from Murchison: Constraints for s-process nucleosynthesis in asymptotic giant branch stars

    SciTech Connect

    Liu, Nan; Davis, Andrew M.; Pellin, Michael J.; Dauphas, Nicolas; Savina, Michael R.; Gallino, Roberto; Bisterzo, Sara; Straniero, Oscar; Cristallo, Sergio; Gyngard, Frank; Willingham, David G.; Pignatari, Marco; Herwig, Falk

    2014-05-01

    We present barium, carbon, and silicon isotopic compositions of 38 acid-cleaned presolar SiC grains from Murchison. Comparison with previous data shows that acid washing is highly effective in removing barium contamination. Strong depletions in δ({sup 138}Ba/{sup 136}Ba) values are found, down to –400‰, which can only be modeled with a flatter {sup 13}C profile within the {sup 13}C pocket than is normally used. The dependence of δ({sup 138}Ba/{sup 136}Ba) predictions on the distribution of {sup 13}C within the pocket in asymptotic giant branch (AGB) models allows us to probe the {sup 13}C profile within the {sup 13}C pocket and the pocket mass in AGB stars. In addition, we provide constraints on the {sup 22}Ne(α, n){sup 25}Mg rate in the stellar temperature regime relevant to AGB stars, based on δ({sup 134}Ba/{sup 136}Ba) values of mainstream grains. We found two nominally mainstream grains with strongly negative δ({sup 134}Ba/{sup 136}Ba) values that cannot be explained by any of the current AGB model calculations. Instead, such negative values are consistent with the intermediate neutron capture process (i process), which is activated by the very late thermal pulse during the post-AGB phase and characterized by a neutron density much higher than the s process. These two grains may have condensed around post-AGB stars. Finally, we report abundances of two p-process isotopes, {sup 130}Ba and {sup 132}Ba, in single SiC grains. These isotopes are destroyed in the s process in AGB stars. By comparing their abundances with respect to that of {sup 135}Ba, we conclude that there is no measurable decay of {sup 135}Cs (t {sub 1/2} = 2.3 Ma) to {sup 135}Ba in individual SiC grains, indicating condensation of barium, but not cesium into SiC grains before {sup 135}Cs decayed.

  10. Branching Morphogenesis

    PubMed Central

    Horowitz, Arie; Simons, Michael

    2009-01-01

    Tubular structures are a fundamental anatomical theme recurring in a wide range of animal species. In mammals, tubulogenesis underscores the development of several systems and organs, including the vascular system, the lungs, and the kidneys. All tubular systems are hierarchical, branching into segments of gradually diminishing diameter. There are only two cell types that form the lumen of tubular systems – either endothelial cells in the vascular system, or epithelial cells in all other organs. The most important feature in determining the morphology of the tubular systems is the frequency and geometry of branching. Hence, deciphering the molecular mechanisms underlying the sprouting of new branches from pre-existing ones is the key to understanding the formation of tubular systems. The morphological similarity between the various tubular systems is underscored by similarities between the signaling pathways which control their branching. A prominent feature common to these pathways is their duality – an agonist counterbalanced by an inhibitor. The formation of the tracheal system in Drosophila melanogaster is driven by fibroblast growth factor (FGF) and inhibited by Sprouty/Notch. In vertebrates, the analogous pathways are FGF and transforming growth factor β in epithelial tubular systems, or vascular endothelial growth factor and Notch in the vascular system. PMID:19179661

  11. The control of branching morphogenesis

    PubMed Central

    Iber, Dagmar; Menshykau, Denis

    2013-01-01

    Many organs of higher organisms are heavily branched structures and arise by an apparently similar process of branching morphogenesis. Yet the regulatory components and local interactions that have been identified differ greatly in these organs. It is an open question whether the regulatory processes work according to a common principle and how far physical and geometrical constraints determine the branching process. Here, we review the known regulatory factors and physical constraints in lung, kidney, pancreas, prostate, mammary gland and salivary gland branching morphogenesis, and describe the models that have been formulated to analyse their impacts. PMID:24004663

  12. FK-DLR properties of a quantum multi-type Bose-gas with a repulsive interaction

    NASA Astrophysics Data System (ADS)

    Suhov, Y.; Stuhl, I.

    2014-08-01

    The paper extends earlier results from Suhov and Kelbert ["FK-DLR states of a quantum Bose-gas with a hardcore interaction," arXiv:1304.0782] and Suhov et al. ["Shift-invariance for FK-DLR states of a 2D quantum Bose-gas," arXiv:1304.4177] about infinite-volume quantum bosonic states (FK-DLR states) to the case of multi-type particles with non-negative interactions. (An example is a quantum Widom-Rowlinson model.) Following the strategy from Suhov and Kelbert and Suhov et al., we establish that, for the values of fugacity z ∈ (0, 1) and inverse temperature β > 0, finite-volume Gibbs states form a compact family in the thermodynamic limit. Next, in dimension two we show that any limit-point state (an FK-DLR state in the terminology adopted in Suhov and Kelbert and Suhov et al.) is translation-invariant.

  13. INTERDISCIPLINARY PHYSICS AND RELATED AREAS OF SCIENCE AND TECHNOLOGY: Branch Processes of Vortex Filaments and Hopf Invariant Constraint on Scroll Wave

    NASA Astrophysics Data System (ADS)

    Zhu, Tao; Ren, Ji-Rong; Mo, Shu-Fan

    2009-12-01

    In this paper, by making use of Duan's topological current theory, the evolution of the vortex filaments in excitable media is discussed in detail. The vortex filaments are found generating or annihilating at the limit points and encountering, splitting, or merging at the bifurcation points of a complex function Z(vec x, t). It is also shown that the Hopf invariant of knotted scroll wave filaments is preserved in the branch processes (splitting, merging, or encountering) during the evolution of these knotted scroll wave filaments. Furthermore, it also revealed that the “exclusion principle" in some chemical media is just the special case of the Hopf invariant constraint, and during the branch processes the “exclusion principle" is also protected by topology.

  14. Combining DCQGMP-Based Sparse Decomposition and MPDR Beamformer for Multi-Type Interferences Mitigation for GNSS Receivers

    PubMed Central

    Guo, Qiang; Qi, Liangang

    2017-01-01

    In the coexistence of multiple types of interfering signals, the performance of interference suppression methods based on time and frequency domains is degraded seriously, and the technique using an antenna array requires a large enough size and huge hardware costs. To combat multi-type interferences better for GNSS receivers, this paper proposes a cascaded multi-type interferences mitigation method combining improved double chain quantum genetic matching pursuit (DCQGMP)-based sparse decomposition and an MPDR beamformer. The key idea behind the proposed method is that the multiple types of interfering signals can be excised by taking advantage of their sparse features in different domains. In the first stage, the single-tone (multi-tone) and linear chirp interfering signals are canceled by sparse decomposition according to their sparsity in the over-complete dictionary. In order to improve the timeliness of matching pursuit (MP)-based sparse decomposition, a DCQGMP is introduced by combining an improved double chain quantum genetic algorithm (DCQGA) and the MP algorithm, and the DCQGMP algorithm is extended to handle the multi-channel signals according to the correlation among the signals in different channels. In the second stage, the minimum power distortionless response (MPDR) beamformer is utilized to nullify the residuary interferences (e.g., wideband Gaussian noise interferences). Several simulation results show that the proposed method can not only improve the interference mitigation degree of freedom (DoF) of the array antenna, but also effectively deal with the interference arriving from the same direction with the GNSS signal, which can be sparse represented in the over-complete dictionary. Moreover, it does not bring serious distortions into the navigation signal. PMID:28394290

  15. Combining DCQGMP-Based Sparse Decomposition and MPDR Beamformer for Multi-Type Interferences Mitigation for GNSS Receivers.

    PubMed

    Guo, Qiang; Qi, Liangang

    2017-04-10

    In the coexistence of multiple types of interfering signals, the performance of interference suppression methods based on time and frequency domains is degraded seriously, and the technique using an antenna array requires a large enough size and huge hardware costs. To combat multi-type interferences better for GNSS receivers, this paper proposes a cascaded multi-type interferences mitigation method combining improved double chain quantum genetic matching pursuit (DCQGMP)-based sparse decomposition and an MPDR beamformer. The key idea behind the proposed method is that the multiple types of interfering signals can be excised by taking advantage of their sparse features in different domains. In the first stage, the single-tone (multi-tone) and linear chirp interfering signals are canceled by sparse decomposition according to their sparsity in the over-complete dictionary. In order to improve the timeliness of matching pursuit (MP)-based sparse decomposition, a DCQGMP is introduced by combining an improved double chain quantum genetic algorithm (DCQGA) and the MP algorithm, and the DCQGMP algorithm is extended to handle the multi-channel signals according to the correlation among the signals in different channels. In the second stage, the minimum power distortionless response (MPDR) beamformer is utilized to nullify the residuary interferences (e.g., wideband Gaussian noise interferences). Several simulation results show that the proposed method can not only improve the interference mitigation degree of freedom (DoF) of the array antenna, but also effectively deal with the interference arriving from the same direction with the GNSS signal, which can be sparse represented in the over-complete dictionary. Moreover, it does not bring serious distortions into the navigation signal.

  16. Fault Branching

    NASA Astrophysics Data System (ADS)

    Dmowska, R.; Rice, J. R.; Poliakov, A. N.

    2001-12-01

    Theoretical stress analysis for a propagating shear rupture suggests that the propensity of the rupture path to branch is determined by rupture speed and by the preexisting stress state. See Poliakov, Dmowska and Rice (JGR, submitted April 2001, URL below). Deviatoric stresses near a mode II rupture tip are found to be much higher to both sides of the fault plane than directly ahead, when rupture speed becomes close to the Rayleigh speed. However, the actual pattern of predicted Coulomb failure on secondary faults is strongly dependent on the angle between the fault and the direction of maximum compression Smax in the pre-stress field. Steep Smax angles lead to more extensive failure on the extensional side, whereas shallow angles give comparable failure regions on both. Here we test such concepts against natural examples. For crustal thrust faults we may assume that Smax is horizontal. Thus nucleation on a steeply dipping plane, like the 53 ° dip for the 1971 San Fernando earthquake, is consistent with rupture path kinking to the extensional side, as inferred. Nucleation on a shallow dip, like for the 12 ° -18 ° of the 1985 Kettleman Hills event, should activate both sides, as seems consistent with aftershock patterns. Similarly, in a strike slip example, Smax is inferred to be at approximately 60 ° with the Johnson Valley fault where it branched to the extensional side onto the Landers-Kickapoo fault in the 1992 event, and this too is consistent. Further, geological examination of the activation of secondary fault features along the Johnson Valley fault and the Homestead Valley fault consistently shows that most activity occurs on the extensional side. Another strike-slip example is the Imperial Valley 1979 earthquake. The approximate Smax direction is north-south, at around 35 ° with the main fault, where it branched, on the extensional side, onto Brawley fault, again interpretable with the concepts developed.

  17. Sustainable Engineering and Improved Recycling of PET for High-Value Applications: Transforming Linear PET to Lightly Branched PET with a Novel, Scalable Process

    NASA Astrophysics Data System (ADS)

    Pierre, Cynthia; Torkelson, John

    2009-03-01

    A major challenge for the most effective recycling of poly(ethylene terephthalate) concerns the fact that initial melt processing of PET into a product leads to substantial degradation of molecular weight. Thus, recycled PET has insufficient melt viscosity for reuse in high-value applications such as melt-blowing of PET bottles. Academic and industrial research has tried to remedy this situation by synthesis and use of ``chain extenders'' that can lead to branched PET (with higher melt viscosity than the linear recycled PET) via condensation reactions with functional groups on the PET. Here we show that simple processing of PET via solid-state shear pulverization (SSSP) leads to enhanced PET melt viscosity without need for chemical additives. We hypothesize that this branching results from low levels of chain scission accompanying SSSP, leading to formation of polymeric radicals that participate in chain transfer and combination reactions with other PET chains and thereby to in situ branch formation. The pulverized PET exhibits vastly enhanced crystallization kinetics, eliminating the need to employ cold crystallization to achieve maximum PET crystallinity. Results of SSSP processing of PET will be compared to results obtained with poly(butylene terephthalate).

  18. Damage Tolerance Assessment Branch

    NASA Technical Reports Server (NTRS)

    Walker, James L.

    2013-01-01

    The Damage Tolerance Assessment Branch evaluates the ability of a structure to perform reliably throughout its service life in the presence of a defect, crack, or other form of damage. Such assessment is fundamental to the use of structural materials and requires an integral blend of materials engineering, fracture testing and analysis, and nondestructive evaluation. The vision of the Branch is to increase the safety of manned space flight by improving the fracture control and the associated nondestructive evaluation processes through development and application of standards, guidelines, advanced test and analytical methods. The Branch also strives to assist and solve non-aerospace related NDE and damage tolerance problems, providing consultation, prototyping and inspection services.

  19. Simple mineral mapping algorithm based on multitype spectral diagnostic absorption features: a case study at Cuprite, Nevada

    NASA Astrophysics Data System (ADS)

    Wei, Jing; Ming, Yanfang; Jia, Qiang; Yang, Dongxu

    2017-04-01

    Hyperspectral remote sensing has been widely used in mineral identification using the particularly useful short-wave infrared (SWIR) wavelengths (1.0 to 2.5 μm). Current mineral mapping methods are easily limited by the sensor's radiometric sensitivity and atmospheric effects. Therefore, a simple mineral mapping algorithm (SMMA) based on the combined application with multitype diagnostic SWIR absorption features for hyperspectral data is proposed. A total of nine absorption features are calculated, respectively, from the airborne visible/infrared imaging spectrometer data, the Hyperion hyperspectral data, and the ground reference spectra data collected from the United States Geological Survey (USGS) spectral library. Based on spectral analysis and statistics, a mineral mapping decision-tree model for the Cuprite mining district in Nevada, USA, is constructed. Then, the SMMA algorithm is used to perform mineral mapping experiments. The mineral map from the USGS (USGS map) in the Cuprite area is selected for validation purposes. Results showed that the SMMA algorithm is able to identify most minerals with high coincidence with USGS map results. Compared with Hyperion data (overall accuracy=74.54%), AVIRIS data showed overall better mineral mapping results (overall accuracy=94.82%) due to low signal-to-noise ratio and high spatial resolution.

  20. FK-DLR properties of a quantum multi-type Bose-gas with a repulsive interaction

    SciTech Connect

    Suhov, Y.; Stuhl, I.

    2014-08-01

    The paper extends earlier results from Suhov and Kelbert [“FK-DLR states of a quantum Bose-gas with a hardcore interaction,” http://arxiv.org/abs/arXiv:1304.0782 ] and Suhov et al. [“Shift-invariance for FK-DLR states of a 2D quantum Bose-gas,” http://arxiv.org/abs/arXiv:1304.4177 ] about infinite-volume quantum bosonic states (FK-DLR states) to the case of multi-type particles with non-negative interactions. (An example is a quantum Widom–Rowlinson model.) Following the strategy from Suhov and Kelbert and Suhov et al., we establish that, for the values of fugacity zϵ(0, 1) and inverse temperature β > 0, finite-volume Gibbs states form a compact family in the thermodynamic limit. Next, in dimension two we show that any limit-point state (an FK-DLR state in the terminology adopted in Suhov and Kelbert and Suhov et al.) is translation-invariant.

  1. Substrate specificities and intracellular distributions of three N-glycan processing enzymes functioning at a key branch point in the insect N-glycosylation pathway.

    PubMed

    Geisler, Christoph; Jarvis, Donald L

    2012-03-02

    Man(α1-6)[GlcNAc(β1-2)Man(α1-3)]ManGlcNAc(2) is a key branch point intermediate in the insect N-glycosylation pathway because it can be either trimmed by a processing β-N-acetylglucosaminidase (FDL) to produce paucimannosidic N-glycans or elongated by N-acetylglucosaminyltransferase II (GNT-II) to produce complex N-glycans. N-acetylglucosaminyltransferase I (GNT-I) contributes to branch point intermediate production and can potentially reverse the FDL trimming reaction. However, there has been no concerted effort to evaluate the relationships among these three enzymes in any single insect system. Hence, we extended our previous studies on Spodoptera frugiperda (Sf) FDL to include GNT-I and -II. Sf-GNT-I and -II cDNAs were isolated, the predicted protein sequences were analyzed, and both gene products were expressed and their acceptor substrate specificities and intracellular localizations were determined. Sf-GNT-I transferred N-acetylglucosamine to Man(5)GlcNAc(2), Man(3)GlcNAc(2), and GlcNAc(β1-2)Man(α1-6)[Man(α1-3)]ManGlcNAc(2), demonstrating its role in branch point intermediate production and its ability to reverse FDL trimming. Sf-GNT-II only transferred N-acetylglucosamine to Man(α1-6)[GlcNAc(β1-2)Man(α1-3)]ManGlcNAc(2), demonstrating that it initiates complex N-glycan production, but cannot use Man(3)GlcNAc(2) to produce hybrid or complex structures. Fluorescently tagged Sf-GNT-I and -II co-localized with an endogenous Sf Golgi marker and Sf-FDL co-localized with Sf-GNT-I and -II, indicating that all three enzymes are Golgi resident proteins. Unexpectedly, fluorescently tagged Drosophila melanogaster FDL also co-localized with Sf-GNT-I and an endogenous Drosophila Golgi marker, indicating that it is a Golgi resident enzyme in insect cells. Thus, the substrate specificities and physical juxtapositioning of GNT-I, GNT-II, and FDL support the idea that these enzymes function at the N-glycan processing branch point and are major factors determining the

  2. Substrate Specificities and Intracellular Distributions of Three N-glycan Processing Enzymes Functioning at a Key Branch Point in the Insect N-Glycosylation Pathway*

    PubMed Central

    Geisler, Christoph; Jarvis, Donald L.

    2012-01-01

    Man(α1–6)[GlcNAc(β1–2)Man(α1–3)]ManGlcNAc2 is a key branch point intermediate in the insect N-glycosylation pathway because it can be either trimmed by a processing β-N-acetylglucosaminidase (FDL) to produce paucimannosidic N-glycans or elongated by N-acetylglucosaminyltransferase II (GNT-II) to produce complex N-glycans. N-Acetylglucosaminyltransferase I (GNT-I) contributes to branch point intermediate production and can potentially reverse the FDL trimming reaction. However, there has been no concerted effort to evaluate the relationships among these three enzymes in any single insect system. Hence, we extended our previous studies on Spodoptera frugiperda (Sf) FDL to include GNT-I and -II. Sf-GNT-I and -II cDNAs were isolated, the predicted protein sequences were analyzed, and both gene products were expressed and their acceptor substrate specificities and intracellular localizations were determined. Sf-GNT-I transferred N-acetylglucosamine to Man5GlcNAc2, Man3GlcNAc2, and GlcNAc(β1–2)Man(α1–6)[Man(α1–3)]ManGlcNAc2, demonstrating its role in branch point intermediate production and its ability to reverse FDL trimming. Sf-GNT-II only transferred N-acetylglucosamine to Man(α1–6)[GlcNAc(β1–2)Man(α1–3)]ManGlcNAc2, demonstrating that it initiates complex N-glycan production, but cannot use Man3GlcNAc2 to produce hybrid or complex structures. Fluorescently tagged Sf-GNT-I and -II co-localized with an endogenous Sf Golgi marker and Sf-FDL co-localized with Sf-GNT-I and -II, indicating that all three enzymes are Golgi resident proteins. Unexpectedly, fluorescently tagged Drosophila melanogaster FDL also co-localized with Sf-GNT-I and an endogenous Drosophila Golgi marker, indicating that it is a Golgi resident enzyme in insect cells. Thus, the substrate specificities and physical juxtapositioning of GNT-I, GNT-II, and FDL support the idea that these enzymes function at the N-glycan processing branch point and are major factors determining the

  3. Properties of the 5{sup -} state at 839 keV in {sup 176}Lu and the s-process branching at A=176

    SciTech Connect

    Mohr, P.; Bisterzo, S.; Gallino, R.; Kaeppeler, F.; Kneissl, U.; Winckler, N.

    2009-04-15

    The s-process branching at mass number A=176 depends on the coupling between the high-K ground state and a low-lying low-K isomer in {sup 176}Lu. This coupling is based on electromagnetic transitions via intermediate states at higher energies. The properties of the lowest experimentally confirmed intermediate state at 839 keV are reviewed, and the transition rate between low-K and high-K states under stellar conditions is calculated on the basis of new experimental data for the 839-keV state. Properties of further candidates for intermediate states are briefly analyzed. It is found that the coupling between the high-K ground state and the low-K isomer in {sup 176}Lu is at least one order of magnitude stronger than previously assumed, leading to crucial consequences for the interpretation of the {sup 176}Lu/{sup 176}Hf pair as an s-process thermometer.

  4. Suspended-sediment yields and stream-channel processes on Judy's Branch watershed in the St. Louis Metro East region in Illinois

    USGS Publications Warehouse

    Straub, Timothy D.; Johnson, Gary P.; Roseboom, Donald P.; Sierra, Carlos R.

    2006-01-01

    Judy's Branch watershed, a small basin (8.64 square miles) in the St. Louis Metro East region in Illinois, was selected as a pilot site to determine suspended-sediment yields and stream-channel processes in the bluffs and American Bottoms (expansive low-lying valley floor in the region). Suspended-sediment and stream-chan-nel data collected and analyzed for Judy's Branch watershed are presented in this report to establish a baseline of data for water-resource managers to evaluate future stream rehabilitation and manage-ment alternatives. The sediment yield analysis determines the amount of sediment being delivered from the watershed and two subwatersheds: an urban tributary and an undeveloped headwater (pri-marily agricultural). The analysis of the subwater-sheds is used to compare the effects of urbanization on sediment yield to the river. The stream-channel contribution to sediment yield was determined by evaluation of the stream-channel processes operat-ing on the streambed and banks of Judy's Branch watershed. Bank stability was related to hydrologic events, bank stratigraphy, and channel geometry through model development and simulation. The average suspended-sediment yield from two upland subwatersheds (drainage areas of 0.23 and 0.40 sq.mi. was 1,163 tons per square mile per year (tons/sq.mi.-year) between July 2000 and June 2004. The suspended-sediment yield at the Route 157 station was 2,523 tons/sq.mi.-year, near the outlet of Judy's Branch watershed (drainage area = 8.33 sq.mi.). This is approximately 1,360 tons/sq.mi.-year greater than the average at the upland stations for the same time period. This result is unexpected in that, generally, the suspended-sediment yield decreases as the watershed area increases because of sediment stored in the channel and flood plain. The difference indicates a possible increase in yield from a source, such as bank retreat, and supports the concept that land-use changes increase stream-flows that may in turn result in

  5. Principles of branch formation and branch patterning in Hydrozoa.

    PubMed

    Berking, Stefan

    2006-01-01

    The freshwater polyp Hydra produces buds which separate from the parent. Other Hydrozoa produce branches which remain connected to the parent, thus forming a colony. Some Hydrozoa grow by means of an organ that is like a shoot apical meristem. Others display a sympodial type of growth. In this article, I propose that these different types of branches are organized by a common pattern-forming system. This system has self-organizing properties. It causes branch tip formation and is kept active in the tip when the tip finally differentiates into a hypostome of a polyp. The system does not cause structure formation directly but rather, determines a tissue property called positional value, in such a way that a gradient of values forms in the tissue of the bud or branch. The local value determines the local morphodynamic processes, including differentiation of the hypostome (highest positional value), tentacles and basal disc and of the exoskeleton pattern along the shoot. A high positional value favors the onset of a new self-organizing process and by lateral inhibition, such a process prevents the initiation of a further process in its surroundings. Small quantitative differences in the range of the signals involved determine whether a bud or a branch forms and whether monopodial and sympodial growth follows.

  6. Long chain branching of PLA

    NASA Astrophysics Data System (ADS)

    Gu, Liangliang; Xu, Yuewen; Fahnhorst, Grant; Macosko, Christopher W.

    2017-05-01

    A trifunctional aziridine linker, trimethylolpropane tris(2-methyl-1-aziridinepropionate) (TTMAP), was melt blended with linear polylactic acid (PLA) to make star branched PLA. Adding pyromellitic dianhydride (PMDA) led to long chain branched (LCB) PLA. Mixing torque evolution during melt processing revealed high reactivity of aziridine with the carboxyl end group on PLA and an incomplete reaction of PMDA with the hydroxyl end group. Star-shaped PLA exhibited higher viscosity but no strain hardening in extensional flow while LCB PLA showed significant extensional hardening. Excess TTMAP in the branching reaction resulted in gel formation, which led to failure at low strain in extension. PMDA conversion was estimated based on gelation theory. The strain rate dependence of extensional hardening indicated that the LCB PLA had a low concentration of long chain branched molecules with an H-shaped topology. Unlike current methods used to branch PLA, free radical chemistry or use of an epoxy functional oligomers, our branching strategy produced strain hardening with less increase in shear viscosity. This study provides guidelines for design of polymers with low shear viscosity, which reduces pressure drop in extrusion, combined with strong extensional hardening, which enhances performance in processes that involve melt stretching.

  7. Growth of branched actin networks against obstacles.

    PubMed Central

    Carlsson, A E

    2001-01-01

    A method for simulating the growth of branched actin networks against obstacles has been developed. The method is based on simple stochastic events, including addition or removal of monomers at filament ends, capping of filament ends, nucleation of branches from existing filaments, and detachment of branches; the network structure for several different models of the branching process has also been studied. The models differ with regard to their inclusion of effects such as preferred branch orientations, filament uncapping at the obstacle, and preferential branching at filament ends. The actin ultrastructure near the membrane in lamellipodia is reasonably well produced if preferential branching in the direction of the obstacle or barbed-end uncapping effects are included. Uncapping effects cause the structures to have a few very long filaments that are similar to those seen in pathogen-induced "actin tails." The dependence of the growth velocity, branch spacing, and network density on the rate parameters for the various processes is quite different among the branching models. An analytic theory of the growth velocity and branch spacing of the network is described. Experiments are suggested that could distinguish among some of the branching models. PMID:11566765

  8. Fault branching and rupture directivity

    NASA Astrophysics Data System (ADS)

    Fliss, Sonia; Bhat, Harsha S.; Dmowska, Renata; Rice, James R.

    2005-06-01

    Could the directivity of a complex earthquake be inferred from the ruptured fault branches it created? Typically, branches develop in forward orientation, making acute angles relative to the propagation direction. Direct backward branching of the same style as the main rupture (e.g., both right lateral) is disallowed by the stress field at the rupture front. Here we propose another mechanism of backward branching. In that mechanism, rupture stops along one fault strand, radiates stress to a neighboring strand, nucleates there, and develops bilaterally, generating a backward branch. Such makes diagnosing directivity of a past earthquake difficult without detailed knowledge of the branching process. As a field example, in the Landers 1992 earthquake, rupture stopped at the northern end of the Kickapoo fault, jumped onto the Homestead Valley fault, and developed bilaterally there, NNW to continue the main rupture but also SSE for 4 km forming a backward branch. We develop theoretical principles underlying such rupture transitions, partly from elastostatic stress analysis, and then simulate the Landers example numerically using a two-dimensional elastodynamic boundary integral equation formulation incorporating slip-weakening rupture. This reproduces the proposed backward branching mechanism based on realistic if simplified fault geometries, prestress orientation corresponding to the region, standard lab friction values for peak strength, and fracture energies characteristic of the Landers event. We also show that the seismic S ratio controls the jumpable distance and that curving of a fault toward its compressional side, like locally along the southeastern Homestead Valley fault, induces near-tip increase of compressive normal stress that slows rupture propagation.

  9. Half-lives and branchings for {beta}-delayed neutron emission for neutron-rich Co-Cu isotopes in the r-process

    SciTech Connect

    Hosmer, P.; Estrade, A.; Montes, F.; Ouellette, M.; Pellegrini, E.; Schatz, H.; Aprahamian, A.; Arndt, O.; Pfeiffer, B.; Clement, R. R. C.; Mueller, W. F.; Morton, A. C.; Pereira, J.; Santi, P.; Steiner, M.; Stolz, A.; Farouqi, K.; Kratz, K.-L.; Liddick, S. N.; Mantica, P. F.

    2010-08-15

    The {beta} decays of very neutron-rich nuclides in the Co-Zn region were studied experimentally at the National Superconducting Cyclotron Laboratory using the NSCL {beta}-counting station in conjunction with the neutron detector NERO. We measured the branchings for {beta}-delayed neutron emission (P{sub n} values) for {sup 74}Co (18{+-}15%) and {sup 75-77}Ni (10{+-}2.8%, 14{+-}3.6%, and 30{+-}24%, respectively) for the first time, and remeasured the P{sub n} values of {sup 77-79}Cu, {sup 79,81}Zn, and {sup 82}Ga. For {sup 77-79}Cu and for {sup 81}Zn we obtain significantly larger P{sub n} values compared to previous work. While the new half-lives for the Ni isotopes from this experiment had been reported before, we present here in addition the first half-life measurements of {sup 75}Co (30{+-}11 ms) and {sup 80}Cu (170{sub -50}{sup +110} ms). Our results are compared with theoretical predictions, and their impact on various types of models for the astrophysical rapid neutron-capture process (r-process) is explored. We find that with our new data, the classical r-process model is better able to reproduce the A=78-80 abundance pattern inferred from the solar abundances. The new data also influence r-process models based on the neutrino-driven high-entropy winds in core collapse supernovae.

  10. Evolutionary branching under slow directional evolution.

    PubMed

    Ito, Hiroshi C; Dieckmann, Ulf

    2014-11-07

    Evolutionary branching is the process by which ecological interactions induce evolutionary diversification. In asexual populations with sufficiently rare mutations, evolutionary branching occurs through trait-substitution sequences caused by the sequential invasion of successful mutants. A necessary and sufficient condition for evolutionary branching of univariate traits is the existence of a convergence stable trait value at which selection is locally disruptive. Real populations, however, undergo simultaneous evolution in multiple traits. Here we extend conditions for evolutionary branching to bivariate trait spaces in which the response to disruptive selection on one trait can be suppressed by directional selection on another trait. To obtain analytical results, we study trait-substitution sequences formed by invasions that possess maximum likelihood. By deriving a sufficient condition for evolutionary branching of bivariate traits along such maximum-likelihood-invasion paths (MLIPs), we demonstrate the existence of a threshold ratio specifying how much disruptive selection in one trait direction is needed to overcome the obstruction of evolutionary branching caused by directional selection in the other trait direction. Generalizing this finding, we show that evolutionary branching of bivariate traits can occur along evolutionary-branching lines on which residual directional selection is sufficiently weak. We then present numerical analyses showing that our generalized condition for evolutionary branching is a good indicator of branching likelihood even when trait-substitution sequences do not follow MLIPs and when mutations are not rare. Finally, we extend the derived conditions for evolutionary branching to multivariate trait spaces.

  11. Three-dimensional self-assembly of networked branched TiO₂ nanocrystal scaffolds for efficient room-temperature processed depleted bulk heterojunction solar cells.

    PubMed

    Loiudice, Anna; Grancini, Giulia; Taurino, Antonietta; Corricelli, Michela; Belviso, Maria R; Striccoli, Marinella; Agostiano, Angela; Curri, M Lucia; Petrozza, Annamaria; Cozzoli, P Davide; Rizzo, Aurora; Gigli, Giuseppe

    2014-04-09

    In this work, we report on ∼4% power conversion efficiency (PCE) depleted bulk heterojunction (DBH) solar cells based on a high-quality electrode with a three-dimensional nanoscale architecture purposely designed so as to maximize light absorption and charge collection. The newly conceived architecture comprises a mesoporous electron-collecting film made of networked anisotropic metal-oxide nanostructures, which accommodates visible-to-infrared light harvesting quantum dots within the recessed regions of its volume. The three-dimensional electrodes were self-assembled by spin-coating a solution of colloidal branched anatase TiO2 NCs (BNC), followed by photocatalytic removal of the native organic capping from their surface by a mild UV-light treatment and filling with small PbS NCs via infiltration. The PCE ∼ 4% of our TiO2 BNC/PbS QD DBH solar cell features an enhancement of 84% over the performance obtained for a planar device fabricated under the same conditions. Overall, the DBH device fabrication procedure is entirely carried out under mild processing conditions at room temperature, thus holding promise for low-cost and large-scale manufacturing.

  12. The allele distribution in next-generation sequencing data sets is accurately described as the result of a stochastic branching process.

    PubMed

    Heinrich, Verena; Stange, Jens; Dickhaus, Thorsten; Imkeller, Peter; Krüger, Ulrike; Bauer, Sebastian; Mundlos, Stefan; Robinson, Peter N; Hecht, Jochen; Krawitz, Peter M

    2012-03-01

    With the availability of next-generation sequencing (NGS) technology, it is expected that sequence variants may be called on a genomic scale. Here, we demonstrate that a deeper understanding of the distribution of the variant call frequencies at heterozygous loci in NGS data sets is a prerequisite for sensitive variant detection. We model the crucial steps in an NGS protocol as a stochastic branching process and derive a mathematical framework for the expected distribution of alleles at heterozygous loci before measurement that is sequencing. We confirm our theoretical results by analyzing technical replicates of human exome data and demonstrate that the variance of allele frequencies at heterozygous loci is higher than expected by a simple binomial distribution. Due to this high variance, mutation callers relying on binomial distributed priors are less sensitive for heterozygous variants that deviate strongly from the expected mean frequency. Our results also indicate that error rates can be reduced to a greater degree by technical replicates than by increasing sequencing depth.

  13. EUROPIUM s-PROCESS SIGNATURE AT CLOSE-TO-SOLAR METALLICITY IN STARDUST SiC GRAINS FROM ASYMPTOTIC GIANT BRANCH STARS

    SciTech Connect

    Avila, Janaina N.; Ireland, Trevor R.; Holden, Peter; Lugaro, Maria; Gyngard, Frank; Zinner, Ernst; Cristallo, Sergio; Rauscher, Thomas

    2013-05-01

    Individual mainstream stardust silicon carbide (SiC) grains and a SiC-enriched bulk sample from the Murchison carbonaceous meteorite have been analyzed by the Sensitive High Resolution Ion Microprobe-Reverse Geometry for Eu isotopes. The mainstream grains are believed to have condensed in the outflows of {approx}1.5-3 M{sub Sun} carbon-rich asymptotic giant branch (AGB) stars with close-to-solar metallicity. The {sup 151}Eu fractions [fr({sup 151}Eu) = {sup 151}Eu/({sup 151}Eu+{sup 153}Eu)] derived from our measurements are compared with previous astronomical observations of carbon-enhanced metal-poor stars enriched in elements made by slow neutron captures (the s-process). Despite the difference in metallicity between the parent stars of the grains and the metal-poor stars, the fr({sup 151}Eu) values derived from our measurements agree well with fr({sup 151}Eu) values derived from astronomical observations. We have also compared the SiC data with theoretical predictions of the evolution of Eu isotopic ratios in the envelope of AGB stars. Because of the low Eu abundances in the SiC grains, the fr({sup 151}Eu) values derived from our measurements show large uncertainties, in most cases being larger than the difference between solar and predicted fr({sup 151}Eu) values. The SiC aggregate yields a fr({sup 151}Eu) value within the range observed in the single grains and provides a more precise result (fr({sup 151}Eu) = 0.54 {+-} 0.03, 95% conf.), but is approximately 12% higher than current s-process predictions. The AGB models can match the SiC data if we use an improved formalism to evaluate the contribution of excited nuclear states in the calculation of the {sup 151}Sm(n, {gamma}) stellar reaction rate.

  14. The s-process in low-metallicity stars - II. Interpretation of high-resolution spectroscopic observations with asymptotic giant branch models

    NASA Astrophysics Data System (ADS)

    Bisterzo, S.; Gallino, R.; Straniero, O.; Cristallo, S.; Käppeler, F.

    2011-11-01

    High-resolution spectroscopic observations of 100 metal-poor carbon and s-rich stars (CEMP-s) collected from the literature are compared with the theoretical nucleosynthesis models of the asymptotic giant branch (AGB) presented in Paper I (MAGBini= 1.3, 1.4, 1.5, 2 M⊙, - 3.6 ≲ [ Fe/H ] ≲- 1.5). The s-process enhancement detected in these objects is associated with binary systems: the more massive companion evolved faster through the thermally pulsing AGB phase (TP-AGB), synthesizing s-elements in the inner He intershell, which are partly dredged up to the surface during the third dredge-up (TDU) episode. The secondary observed low-mass companion became CEMP-s by the mass transfer of C- and s-rich material from the primary AGB. We analyse the light elements C, N, O, Na and Mg, as well as the two s-process indicators, [hs/ls] (where ls = is the the light-s peak at N = 50 and hs = the heavy-s peak at N = 82) and [Pb/hs]. We distinguish between CEMP-s with high s-process enhancement, [hs/Fe] >rsim 1.5 (CEMP-sII), and mild s-process enhanced stars, [hs/Fe] < 1.5 (CEMP-sI). To interpret the observations, a range of s-process efficiencies at any given metallicity is necessary. This is confirmed by the high spread observed in [Pb/hs] (˜2 dex). A degeneration of solutions is found with some exceptions: most main-sequence CEMP-sII stars with low [Na/Fe] can only be interpreted with MAGBini= 1.3-1.4 M⊙. Giants having suffered the first dredge-up (FDU) need a dilution >rsim1 dex (dil is defined as the mass of the convective envelope of the observed star, Mobs★, over the material transferred from the AGB to the companion, MtransAGB). Then AGB models with higher AGB initial masses (MAGBini= 1.5-2 M⊙) are adopted to interpret CEMP-sII giants. In general, solutions with AGB models in the mass range MAGBini= 1.3-2 M⊙ and different dilution factors are found for CEMP-sI stars. About half of the CEMP-s stars with europium measurements show a high r-process

  15. Quantitative Analysis of the Side Branch Orifice after Bifurcation Stenting Using En Face Processing of OCT Images: A Comparison between Xience V and Resolute Integrity Stent

    PubMed Central

    Minami, Yoshiyasu; Wang, Zhao; Aguirre, Aaron D.; Lee, Stephen; Uemura, Shiro; Soeda, Tsunenari; Vergallo, Rocco; Raffel, O. Christopher; Barlis, Peter; Itoh, Tomonori; Lee, Hang; Fujimoto, James; Jang, Ik-Kyung

    2015-01-01

    Objective Methods for intravascular assessment of the side branch (SB) orifice after stenting are not readily available. The aim of this study is to assess the utility of an en face projection processing for optical coherence tomography (OCT) images for the SB evaluation. Methods Measurements of the SB orifice using en face OCT images were validated using a phantom model. Linear regression modeling was applied to estimated area measurements made on the en face images. The SB orifice was then analyzed in 88 patients with bifurcation lesions treated with either a Xience V (EES) or a Resolute Integrity (ZES). The SB orifice area (A) and the area obstructed by struts (B) were calculated, and the %open area was evaluated as (A-B)/A*100. Results Linear regression modeling demonstrated observed departures of the intercept and slope was not significantly different from 0 (−0.12 ± 0.22, p=0.59) and from 1 (1.01 ± 0.06, R2=0.88, p=0.87), respectively. In cases without SB dilatation, the %open area was significantly larger in EES group (n=25) than in ZES group (n=32) (89.2% [83.7–91.3] vs. 84.3% [78.9–87.8], P=0.04). A significant difference in the %open area between with and without SB dilatation was demonstrated in the ZES group (91.4% [86.1–94.0] vs. 84.3% [78.9–87.8], P=0.04). Conclusions The accuracy of SB orifice measurement on the en face OCT image was validated using a phantom model. This novel approach can quantitatively evaluate the differences in SB orifice area free from struts among different stent types and different treatment strategies in vivo. PMID:26554662

  16. Critical role of alkyl chain branching of organic semiconductors in enabling solution-processed N-channel organic thin-film transistors with mobility of up to 3.50 cm² V(-1) s(-1).

    PubMed

    Zhang, Fengjiao; Hu, Yunbin; Schuettfort, Torben; Di, Chong-an; Gao, Xike; McNeill, Christopher R; Thomsen, Lars; Mannsfeld, Stefan C B; Yuan, Wei; Sirringhaus, Henning; Zhu, Daoben

    2013-02-13

    Substituted side chains are fundamental units in solution processable organic semiconductors in order to achieve a balance of close intermolecular stacking, high crystallinity, and good compatibility with different wet techniques. Based on four air-stable solution-processed naphthalene diimides fused with 2-(1,3-dithiol-2-ylidene)malononitrile groups (NDI-DTYM2) that bear branched alkyl chains with varied side-chain length and different branching position, we have carried out systematic studies on the relationship between film microstructure and charge transport in their organic thin-film transistors (OTFTs). In particular synchrotron measurements (grazing incidence X-ray diffraction and near-edge X-ray absorption fine structure) are combined with device optimization studies to probe the interplay between molecular structure, molecular packing, and OTFT mobility. It is found that the side-chain length has a moderate influence on thin-film microstructure but leads to only limited changes in OTFT performance. In contrast, the position of branching point results in subtle, yet critical changes in molecular packing and leads to dramatic differences in electron mobility ranging from ~0.001 to >3.0 cm(2) V(-1) s(-1). Incorporating a NDI-DTYM2 core with three-branched N-alkyl substituents of C(11,6) results in a dense in-plane molecular packing with an unit cell area of 127 Å(2), larger domain sizes of up to 1000 × 3000 nm(2), and an electron mobility of up to 3.50 cm(2) V(-1) s(-1), which is an unprecedented value for ambient stable n-channel solution-processed OTFTs reported to date. These results demonstrate that variation of the alkyl chain branching point is a powerful strategy for tuning of molecular packing to enable high charge transport mobilities.

  17. Cash efficiency for bank branches.

    PubMed

    Cabello, Julia García

    2013-01-01

    Bank liquidity management has become a major issue during the financial crisis as liquidity shortages have intensified and have put pressure on banks to diversity and improve their liquidity sources. While a significant strand of the literature concentrates on wholesale liquidity generation and on the alternative to deposit funding, the management of an inventory of cash holdings within the banks' branches is also a relevant issue as any significant improvement in cash management at the bank distribution channels may have a positive effect in reducing liquidity tensions. In this paper, we propose a simple programme of cash efficiency for the banks' branches, very easy to implement, which conform to a set of instructions to be imposed from the bank to their branches. This model proves to significantly reduce cash holdings at branches thereby providing efficiency improvements in liquidity management. The methodology we propose is based on the definition of some stochastic processes combined with renewal processes, which capture the random elements of the cash flow, before applying suitable optimization programmes to all the costs involved in cash movements. The classical issue of the Transaction Demand for the Cash and some aspects of Inventory Theory are also present. Mathematics Subject Classification (2000) C02, C60, E50.

  18. Lung epithelial branching program antagonizes alveolar differentiation.

    PubMed

    Chang, Daniel R; Martinez Alanis, Denise; Miller, Rachel K; Ji, Hong; Akiyama, Haruhiko; McCrea, Pierre D; Chen, Jichao

    2013-11-05

    Mammalian organs, including the lung and kidney, often adopt a branched structure to achieve high efficiency and capacity of their physiological functions. Formation of a functional lung requires two developmental processes: branching morphogenesis, which builds a tree-like tubular network, and alveolar differentiation, which generates specialized epithelial cells for gas exchange. Much progress has been made to understand each of the two processes individually; however, it is not clear whether the two processes are coordinated and how they are deployed at the correct time and location. Here we show that an epithelial branching morphogenesis program antagonizes alveolar differentiation in the mouse lung. We find a negative correlation between branching morphogenesis and alveolar differentiation temporally, spatially, and evolutionarily. Gain-of-function experiments show that hyperactive small GTPase Kras expands the branching program and also suppresses molecular and cellular differentiation of alveolar cells. Loss-of-function experiments show that SRY-box containing gene 9 (Sox9) functions downstream of Fibroblast growth factor (Fgf)/Kras to promote branching and also suppresses premature initiation of alveolar differentiation. We thus propose that lung epithelial progenitors continuously balance between branching morphogenesis and alveolar differentiation, and such a balance is mediated by dual-function regulators, including Kras and Sox9. The resulting temporal delay of differentiation by the branching program may provide new insights to lung immaturity in preterm neonates and the increase in organ complexity during evolution.

  19. Mechanisms of Side Branching and Tip Splitting in a Model of Branching Morphogenesis

    PubMed Central

    Guo, Yina; Sun, Mingzhu; Garfinkel, Alan; Zhao, Xin

    2014-01-01

    Recent experimental work in lung morphogenesis has described an elegant pattern of branching phenomena. Two primary forms of branching have been identified: side branching and tip splitting. In our previous study of lung branching morphogenesis, we used a 4 variable partial differential equation (PDE), due to Meinhardt, as our mathematical model to describe the reaction and diffusion of morphogens creating those branched patterns. By altering key parameters in the model, we were able to reproduce all the branching styles and the switch between branching modes. Here, we attempt to explain the branching phenomena described above, as growing out of two fundamental instabilities, one in the longitudinal (growth) direction and the other in the transverse direction. We begin by decoupling the original branching process into two semi-independent sub-processes, 1) a classic activator/inhibitor system along the growing stalk, and 2) the spatial growth of the stalk. We then reduced the full branching model into an activator/inhibitor model that embeds growth of the stalk as a controllable parameter, to explore the mechanisms that determine different branching patterns. We found that, in this model, 1) side branching results from a pattern-formation instability of the activator/inhibitor subsystem in the longitudinal direction. This instability is far from equilibrium, requiring a large inhomogeneity in the initial conditions. It successively creates periodic activator peaks along the growing stalk, each of which later on migrates out and forms a side branch; 2) tip splitting is due to a Turing-style instability along the transversal direction, that creates the spatial splitting of the activator peak into 2 simultaneously-formed peaks at the growing tip, the occurrence of which requires the widening of the growing stalk. Tip splitting is abolished when transversal stalk widening is prevented; 3) when both instabilities are satisfied, tip bifurcation occurs together with side

  20. Bundle Branch Block

    MedlinePlus

    ... your heart to pump blood efficiently through your circulatory system. There's no specific treatment for bundle branch block itself. However, any underlying health condition that caused bundle branch block, such as heart disease, will need to be treated. In most people, ...

  1. Melons are Branched Polymers

    NASA Astrophysics Data System (ADS)

    Gurau, Razvan; Ryan, James P.

    2014-11-01

    Melonic graphs constitute the family of graphs arising at leading order in the 1/N expansion of tensor models. They were shown to lead to a continuum phase, reminiscent of branched polymers. We show here that they are in fact precisely branched polymers, that is, they possess Hausdorff dimension 2 and spectral dimension 4/3.

  2. Randomized branch sampling

    Treesearch

    Harry T. Valentine

    2002-01-01

    Randomized branch sampling (RBS) is a special application of multistage probability sampling (see Sampling, environmental), which was developed originally by Jessen [3] to estimate fruit counts on individual orchard trees. In general, the method can be used to obtain estimates of many different attributes of trees or other branched plants. The usual objective of RBS is...

  3. Turing mechanism underlying a branching model for lung morphogenesis

    PubMed Central

    Sun, Mingzhu

    2017-01-01

    The mammalian lung develops through branching morphogenesis. Two primary forms of branching, which occur in order, in the lung have been identified: tip bifurcation and side branching. However, the mechanisms of lung branching morphogenesis remain to be explored. In our previous study, a biological mechanism was presented for lung branching pattern formation through a branching model. Here, we provide a mathematical mechanism underlying the branching patterns. By decoupling the branching model, we demonstrated the existence of Turing instability. We performed Turing instability analysis to reveal the mathematical mechanism of the branching patterns. Our simulation results show that the Turing patterns underlying the branching patterns are spot patterns that exhibit high local morphogen concentration. The high local morphogen concentration induces the growth of branching. Furthermore, we found that the sparse spot patterns underlie the tip bifurcation patterns, while the dense spot patterns underlies the side branching patterns. The dispersion relation analysis shows that the Turing wavelength affects the branching structure. As the wavelength decreases, the spot patterns change from sparse to dense, the rate of tip bifurcation decreases and side branching eventually occurs instead. In the process of transformation, there may exists hybrid branching that mixes tip bifurcation and side branching. Since experimental studies have reported that branching mode switching from side branching to tip bifurcation in the lung is under genetic control, our simulation results suggest that genes control the switch of the branching mode by regulating the Turing wavelength. Our results provide a novel insight into and understanding of the formation of branching patterns in the lung and other biological systems. PMID:28376090

  4. Fine-Branched Ridges

    NASA Image and Video Library

    2015-10-14

    This image from NASA Mars Reconnaissance Orbiter spacecraft shows numerous branching ridges with various degrees of sinuosity. These branching forms resemble tributaries funneling and draining into larger channel trunks towards the upper portion of the scene. The raised relief of these branching ridges suggests that these are ancient channels are inverted due to lithification and cementation of the riverbed sediment, which made it more resistant to erosion than the surrounding material. Wind-blown bedforms are abundant and resemble small ridges that are aligned in an approximately north-south direction. http://photojournal.jpl.nasa.gov/catalog/PIA20006

  5. Restoration technology branch

    USGS Publications Warehouse

    ,

    2007-01-01

    The mission of Leetown Science Center (LSC), Restoration Technology Branch (RTB) is to conduct research needed to restore or protect the chemical, physical and biological integrity of desirable aquatic systems.

  6. The Olive Branch Awards.

    ERIC Educational Resources Information Center

    Harnack, William

    1984-01-01

    The first annual Olive Branch Awards, sponsored by the Writers' and Publishers Alliance and the Editors' Organizing Committee, were given to ten magazines, out of 60 that submitted entries. Winning entries are described briefly. (IM)

  7. The Olive Branch Awards.

    ERIC Educational Resources Information Center

    Harnack, William

    1984-01-01

    The first annual Olive Branch Awards, sponsored by the Writers' and Publishers Alliance and the Editors' Organizing Committee, were given to ten magazines, out of 60 that submitted entries. Winning entries are described briefly. (IM)

  8. An archetypal mechanism for branching organogenesis.

    PubMed

    Clément, Raphaël; Mauroy, Benjamin

    2014-02-01

    Branched structures are ubiquitous in nature, both in living and non-living systems. While the functional benefits of branching organogenesis are straightforward, the developmental mechanisms leading to the repeated branching of epithelia in surrounding mesoderm remain unclear. Both molecular and physical aspects of growth control seem to play a critical role in shape emergence and maintenance. On the molecular side, the existence of a gradient of growth-promoting ligand between epithelial tips and distal mesenchyme seems to be common to branched organs. On the physical side, the branching process seems to require a mechanism of real-time adaptation to local geometry, as suggested by the self-avoiding nature of branching events. In this paper, we investigate the outcomes of a general three-dimensional growth model, in which epithelial growth is implemented as a function of ligand income, while the mesenchyme is considered as a proliferating viscous medium. Our results suggest that the existence of a gradient of growth-promoting ligand between distal and proximal mesenchyme implies a growth instability of the epithelial sheet, resulting in spontaneous self-avoiding branching morphogenesis. While the general nature of the model prevents one from fitting the development of specific organs, it suggests that few ingredients are actually required to achieve branching organogenesis.

  9. 12 CFR 208.6 - Establishment and maintenance of branches.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... processing under § 225.14(c) of Regulation Y (12 CFR 225.14(c)). (2) Expedited procedures. A completed... 12 Banks and Banking 2 2013-01-01 2013-01-01 false Establishment and maintenance of branches. 208... maintenance of national bank branches (12 U.S.C. 36 and 1831u), except that approval of such branches shall...

  10. 12 CFR 208.6 - Establishment and maintenance of branches.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... processing under § 225.14(c) of Regulation Y (12 CFR 225.14(c)). (2) Expedited procedures. A completed... 12 Banks and Banking 2 2012-01-01 2012-01-01 false Establishment and maintenance of branches. 208... maintenance of national bank branches (12 U.S.C. 36 and 1831u), except that approval of such branches shall...

  11. 12 CFR 208.6 - Establishment and maintenance of branches.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... processing under § 225.14(c) of Regulation Y (12 CFR 225.14(c)). (2) Expedited procedures. A completed... 12 Banks and Banking 2 2011-01-01 2011-01-01 false Establishment and maintenance of branches. 208... maintenance of national bank branches (12 U.S.C. 36 and 1831u), except that approval of such branches shall...

  12. 12 CFR 208.6 - Establishment and maintenance of branches.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... processing under § 225.14(c) of Regulation Y (12 CFR 225.14(c)). (2) Expedited procedures. A completed... 12 Banks and Banking 2 2014-01-01 2014-01-01 false Establishment and maintenance of branches. 208... maintenance of national bank branches (12 U.S.C. 36 and 1831u), except that approval of such branches shall...

  13. Walker Branch Watershed Ecosystems Data

    DOE Data Explorer

    Walker Branch Watershed is located on the U. S. Department of Energy's Oak Ridge Reservation near Oak Ridge, in Anderson County, Tennessee. The Walker Branch Watershed Project began in 1967 under sponsorship of the U. S. Atomic Energy Commission (now the U. S. Department of Energy). Initially, the project centered primarily on the geologic and hydrologic processes that control the amounts and chemistry of water moving through the watershed. Past projects have included: • U. S. Department of Energy funded studies of watershed hydrology and forest nutrient dynamics • National Oceanic and Atmospheric Administration funded studies of forest micrometeorology • Studies of atmospheric deposition under the National Atmospheric Deposition Program • The International Biological Program Eastern Deciduous Forest Biome Project • National Science Foundation sponsored studies of trace element cycling and stream nutrient spiraling • Electric Power Research Institute funded studies of the effects of acidic deposition on canopy processes and soil chemistry. These projects have all contributed to a more complete understanding of how forest watersheds function and have provided insights into the solution of energy-related problems associated with air pollution, contaminant transport, and forest nutrient dynamics. This is one of a few sites in the world characterized by long-term, intensive environmental studies. The Walker Branch Watershed website at http://walkerbranch.ornl.gov/ provides maps, photographs, and data on climate, precipitation, atmospheric deposition, stream discharge and runoff, stream chemistry, and vegetation. [Taken from http://walkerbranch.ornl.gov/ABOUTAAA.HTM

  14. Disassortativity of random critical branching trees.

    PubMed

    Kim, J S; Kahng, B; Kim, D

    2009-06-01

    Random critical branching trees (CBTs) are generated by the multiplicative branching process, where the branching number is determined stochastically, independent of the degree of their ancestor. Here we show analytically that despite this stochastic independence, there exists the degree-degree correlation (DDC) in the CBT and it is disassortative. Moreover, the skeletons of fractal networks, the maximum spanning trees formed by the edge betweenness centrality, behave similarly to the CBT in the DDC. This analytic solution and observation support the argument that the fractal scaling in complex networks originates from the disassortativity in the DDC.

  15. Small heat shock protein IbpB acts as a robust chaperone in living cells by hierarchically activating its multi-type substrate-binding residues.

    PubMed

    Fu, Xinmiao; Shi, Xiaodong; Yin, Linxiang; Liu, Jiafeng; Joo, Keehyoung; Lee, Jooyoung; Chang, Zengyi

    2013-04-26

    As ubiquitous molecular chaperones, small heat shock proteins (sHSPs) are crucial for protein homeostasis. It is not clear why sHSPs are able to bind a wide spectrum of non-native substrate proteins and how such binding is enhanced by heat shock. Here, by utilizing a genetically incorporated photo-cross-linker (p-benzoyl-l-phenylalanine), we systematically characterized the substrate-binding residues in IbpB (a sHSP from Escherichia coli) in living cells over a wide spectrum of temperatures (from 20 to 50 °C). A total of 20 and 48 residues were identified at normal and heat shock temperatures, respectively. They are not necessarily hydrophobic and can be classified into three types: types I and II were activated at low and normal temperatures, respectively, and type III mediated oligomerization at low temperature but switched to substrate binding at heat shock temperature. In addition, substrate binding of IbpB in living cells began at temperatures as low as 25 °C and was further enhanced upon temperature elevation. Together, these in vivo data provide novel structural insights into the wide substrate spectrum of sHSPs and suggest that sHSP is able to hierarchically activate its multi-type substrate-binding residues and thus act as a robust chaperone in cells under fluctuating growth conditions.

  16. Pen Branch delta expansion

    SciTech Connect

    Nelson, E.A.; Christensen, E.J.; Mackey, H.E.; Sharitz, R.R.; Jensen, J.R.; Hodgson, M.E.

    1984-02-01

    Since 1954, cooling water discharges from K Reactor ({anti X} = 370 cfs {at} 59 C) to Pen Branch have altered vegetation and deposited sediment in the Savannah River Swamp forming the Pen Branch delta. Currently, the delta covers over 300 acres and continues to expand at a rate of about 16 acres/yr. Examination of delta expansion can provide important information on environmental impacts to wetlands exposed to elevated temperature and flow conditions. To assess the current status and predict future expansion of the Pen Branch delta, historic aerial photographs were analyzed using both basic photo interpretation and computer techniques to provide the following information: (1) past and current expansion rates; (2) location and changes of impacted areas; (3) total acreage presently affected. Delta acreage changes were then compared to historic reactor discharge temperature and flow data to see if expansion rate variations could be related to reactor operations.

  17. Branched Hamiltonians and supersymmetry

    DOE PAGES

    Curtright, Thomas L.; Zachos, Cosmas K.

    2014-03-21

    Some examples of branched Hamiltonians are explored both classically and in the context of quantum mechanics, as recently advocated by Shapere and Wilczek. These are in fact cases of switchback potentials, albeit in momentum space, as previously analyzed for quasi-Hamiltonian chaotic dynamical systems in a classical setting, and as encountered in analogous renormalization group flows for quantum theories which exhibit RG cycles. In conclusion, a basic two-worlds model, with a pair of Hamiltonian branches related by supersymmetry, is considered in detail.

  18. On linear birth-and-death processes in a random environment.

    PubMed

    Bacaër, Nicolas; Ed-Darraz, Abdelkarim

    2014-07-01

    We study the probability of extinction for single-type and multi-type continuous-time linear birth-and-death processes in a finite Markovian environment. The probability of extinction is equal to 1 almost surely if and only if the basic reproduction number R(0) is ≤ 1, the key point being to identify a suitable definition of R(0) for such a result to hold.

  19. LETTER TO THE EDITOR: U(1) × U(1) × U(1) symmetry of the Kimura 3ST model and phylogenetic branching processes

    NASA Astrophysics Data System (ADS)

    Bashford, J. D.; Jarvis, P. D.; Sumner, J. G.; Steel, M. A.

    2004-02-01

    An analysis of the Kimura 3ST model of DNA sequence evolution is given on the basis of its continuous Lie symmetries. The rate matrix commutes with a U(1) × U(1) × U(1) phase subgroup of the group GL(4) of 4 × 4 invertible complex matrices acting on a linear space spanned by the four nucleic acid base letters. The diagonal 'branching operator' representing speciation is defined, and shown to intertwine the U(1) × U(1) × U(1) action. Using the intertwining property, a general formula for the probability density on the leaves of a binary tree under the Kimura model is derived, which is shown to be equivalent to established phylogenetic spectral transform methods.

  20. The Impact of Updated Zr Neutron-capture Cross Sections and New Asymptotic Giant Branch Models on our Understanding of the s process and the origin of stardust

    DOE PAGES

    Lugaro, M.; Tagliente, Giuseppe; Karakas, Amanda I.; ...

    2013-12-13

    We present model predictions for the Zr isotopic ratios produced by slow neutron captures in C-rich asymptotic giant branch (AGB) stars of masses 1.25-4 M-circle dot and metallicities Z = 0.01-0.03, and compare them to data from single meteoritic stardust silicon carbide (SiC) and high-density graphite grains that condensed in the outflows of these stars. We compare predictions produced using the Zr neutron-capture cross sections from Bao et al. and from n_TOF experiments at CERN, and present a new evaluation for the neutron-capture cross section of the unstable isotope Zr-95, the branching point leading to the production of Zr-96. Themore » new cross sections generally present an improved match with the observational data, except for the Zr-92/Zr-94 ratios, which are on average still substantially higher than predicted. The Zr-96/Zr-94 ratios can be explained using our range of initial stellar masses, with the most Zr-96-depleted grains originating from AGB stars of masses 1.8-3 M-circle dot and the others from either lower or higher masses. The Zr-90,Zr-91/Zr-94 variations measured in the grains are well reproduced by the range of stellar metallicities considered here, which is the same needed to cover the Si composition of the grains produced by the chemical evolution of the Galaxy. The Zr-92/Zr-94 versus Si-29/Si-28 positive correlation observed in the available data suggests that stellar metallicity rather than rotation plays the major role in covering the Zr-90,Zr-91,Zr-92/Zr-94 spread« less

  1. The Impact of Updated Zr Neutron-capture Cross Sections and New Asymptotic Giant Branch Models on our Understanding of the s process and the origin of stardust

    SciTech Connect

    Lugaro, M.; Tagliente, Giuseppe; Karakas, Amanda I.; Milazzo, Paolo M.; Kappeler, Franz; Davis, Andrew M.; Savina, Michael R.

    2013-12-13

    We present model predictions for the Zr isotopic ratios produced by slow neutron captures in C-rich asymptotic giant branch (AGB) stars of masses 1.25-4 M-circle dot and metallicities Z = 0.01-0.03, and compare them to data from single meteoritic stardust silicon carbide (SiC) and high-density graphite grains that condensed in the outflows of these stars. We compare predictions produced using the Zr neutron-capture cross sections from Bao et al. and from n_TOF experiments at CERN, and present a new evaluation for the neutron-capture cross section of the unstable isotope Zr-95, the branching point leading to the production of Zr-96. The new cross sections generally present an improved match with the observational data, except for the Zr-92/Zr-94 ratios, which are on average still substantially higher than predicted. The Zr-96/Zr-94 ratios can be explained using our range of initial stellar masses, with the most Zr-96-depleted grains originating from AGB stars of masses 1.8-3 M-circle dot and the others from either lower or higher masses. The Zr-90,Zr-91/Zr-94 variations measured in the grains are well reproduced by the range of stellar metallicities considered here, which is the same needed to cover the Si composition of the grains produced by the chemical evolution of the Galaxy. The Zr-92/Zr-94 versus Si-29/Si-28 positive correlation observed in the available data suggests that stellar metallicity rather than rotation plays the major role in covering the Zr-90,Zr-91,Zr-92/Zr-94 spread

  2. Branching in rice.

    PubMed

    Wang, Yonghong; Li, Jiayang

    2011-02-01

    Rice branching, including the formation of tillers and panicle branches, has been well investigated over the past several years because of its agronomic importance. A major breakthrough in elucidating rice tillering in the recent years was the discovery of strigolactones, a specific group of terpenoid lactones that can inhibit axillary bud outgrowth. Since that discovery, new tillering mutants, that is, dwarf 27 (d27) or dwarf14 (d14, also reported as d88 or htd2), have been identified with reduced strigolactone levels or strigolactone response. DWARF27 (D27) and DWARF14 (D14) probably act on strigolactone biosynthesis and signal transduction, respectively. Additionally, several genes controlling panicle branches have been identified recently. DEP1 and IPA1/WFP are essential dominant/semidominant regulators that determine rice panicle branches and thus affect the grain yields. More importantly, dep1 and ipa1 alleles have been shown to be applicable for the improvement of rice grain yields in molecular breeding. Copyright © 2010 Elsevier Ltd. All rights reserved.

  3. New branched DNA constructs.

    PubMed

    Chandra, Madhavaiah; Keller, Sascha; Gloeckner, Christian; Bornemann, Benjamin; Marx, Andreas

    2007-01-01

    The Watson-Crick base pairing of DNA is an advantageous phenomenon that can be exploited when using DNA as a scaffold for directed self-organization of nanometer-sized objects. Several reports have appeared in the literature that describe the generation of branched DNA (bDNA) with variable numbers of arms that self-assembles into predesigned architectures. These bDNA units are generated by using cleverly designed rigid crossover DNA molecules. Alternatively, bDNA can be generated by using synthetic branch points derived from either nucleoside or non-nucleoside building blocks. Branched DNA has scarcely been explored for use in nanotechnology or from self-assembling perspectives. Herein, we wish to report our results for the synthesis, characterization, and assembling properties of asymmetrical bDNA molecules that are able to generate linear and circular bDNA constructs. Our strategy for the generation of bDNA is based on a branching point that makes use of a novel protecting-group strategy. The bDNA units were generated by means of automated DNA synthesis methods and were used to generate novel objects by employing chemical and biological techniques. The entities generated might be useful building blocks for DNA-based nanobiotechnology.

  4. Front Range Branch Officers

    NASA Astrophysics Data System (ADS)

    The Front Range Branch of AGU has installed officers for 1990: Ray Noble, National Center for Atmospheric Research, chair; Sherry Oaks, U.S. Geological Survey, chair-elect; Howard Garcia, NOAA, treasurer; Catharine Skokan, Colorado School of Mines, secretary. JoAnn Joselyn of NOAA is past chair. Members at large are Wallace Campbell, NOAA; William Neff, USGS; and Stephen Schneider, NCAR.

  5. Radioiodinated branched carbohydrates

    DOEpatents

    Goodman, Mark M.; Knapp, Jr., Furn F.

    1989-01-01

    A radioiodinated branched carbohydrate for tissue imaging. Iodine-123 is stabilized in the compound by attaching it to a vinyl functional group that is on the carbohydrate. The compound exhibits good uptake and retention and is promising in the development of radiopharmaceuticals for brain, heart and tumor imaging.

  6. Branching structure and strain hardening of branched metallocene polyethylenes

    SciTech Connect

    Torres, Enrique; Li, Si-Wan; Costeux, Stéphane; Dealy, John M.

    2015-09-15

    There have been a number of studies of a series of branched metallocene polyethylenes (BMPs) made in a solution, continuous stirred tank reactor (CSTR) polymerization. The materials studied vary in branching level in a systematic way, and the most highly branched members of the series exhibit mild strain hardening. An outstanding question is which types of branched molecules are responsible for strain hardening in extension. This question is explored here by use of polymerization and rheological models along with new data on the extensional flow behavior of the most highly branched members of the set. After reviewing all that is known about the effects of various branching structures in homogeneous polymers and comparing this with the structures predicted to be present in BMPs, it is concluded that in spite of their very low concentration, treelike molecules with branch-on-branch structure provide a large number of deeply buried inner segments that are essential for strain hardening in these polymers.

  7. Joint Inversion of Multi-type and Time-lapse Airborne Electromagnetic Data Sets for Tempo-spatial Variation of Groundwater Salinity

    NASA Astrophysics Data System (ADS)

    Yang, D.; Oldenburg, D.

    2016-12-01

    The salinization of the floodplains of Lower Murray River in South Australia has caused negative consequences to the local ecosystem. As part of the Living Murray Initiative, the Clark's Floodplain at Bookpurnong was chosen to examine the effectiveness of different intervention methods from 2005 to 2008. Because of the link between groundwater salinity and electric conductivity, electromagnetic (EM) methods have been an integrated part of the project to test it as a cost-effective tool for monitoring. In this paper, we analyze two airborne EM surveys that assess the salinization at the regional scale: the SkyTEM in 2006 and the RESOLVE in 2008. Conventional interpretation often inverts those data sets separately using the 1D layered earth modeling, which often produces inconsistent images if different surveys are carried out at different times. Here we propose a new approach that considers the coherence in time and across systems. We allow each data set to iteratively construct its own model with guidance from a common reference model that is updated in a democratic voting procedure after every iteration. There are two possible outcomes. If the data sets are intrinsically compatible, the individual models will converge to essentially the same model, like in the regular unimodal joint inversion. If there are survey-specific errors or a change of ground truth, the inversion can still fit the data but leaves discrepancy in the models. By applying this approach to the two data sets at Bookpurnong, we identify an area of increased conductivity at the midstream section of the river that can only be explained by a temporal variation of salinity, a plausible evidence of escalated saline water intrusion due to irrigation on the nearby riverbank. This study illustrates that multi-type time-lapse EM, in conjunction with advanced inversion techniques, can achieve superior temporal resolution for the purpose of groundwater evaluation and management.

  8. NRAGE: a potential rheostat during branching morphogenesis.

    PubMed

    Nikopoulos, George N; Martins, Joao Ferreira; Adams, Tamara L; Karaczyn, Aldona; Adams, Derek; Vary, Calvin; Oxburgh, Leif; Verdi, Joseph M

    2009-01-01

    Branching morphogenesis is a developmental process characteristic of many organ systems. Specifically, during renal branching morphogenesis, its been postulated that the final number of nephrons formed is one key clinical factor in the development of hypertension in adulthood. As it has been established that BMPs regulate, in part, renal activity of p38 MAP kinase (p38(MAPK)) and it has demonstrated that the cytoplasmic protein Neurotrophin Receptor MAGE homologue (NRAGE) augments p38(MAPK) activation, it was hypothesized that a decrease in the expression of NRAGE during renal branching would result in decreased branching of the UB that correlated with changes in p38(MAPK) activation. To verify this, the expression of NRAGE was reduced in ex vivo kidney explants cultures using antisense morpholino. Morpholino treated ex vivo kidney explants expression were severely stunted in branching, a trait that was rescued with the addition of exogenous GDNF. Renal explants also demonstrated a precipitous drop in p38(MAPK) activation that too was reversed in the presence of recombinant GDNF. RNA profiling of NRAGE diminished ex vivo kidney explants resulted in altered expression of GDNF, Ret, BMP7 and BMPRIb mRNAs. Our results suggested that in early kidney development NRAGE might have multiple roles during renal branching morphogenesis through association with both the BMP and GDNF signaling pathways.

  9. NRAGE: A Potential Rheostat During Branching Morphogenesis

    PubMed Central

    Nikopoulos, George N.; Martins, Joao Ferreira; Adams, Tamara L.; Karaczyn, Aldona; Adams, Derek; Vary, Calvin; Verdi, Joseph M.

    2009-01-01

    Branching morphogenesis is a developmental process characteristic of many organ systems. Specifically, during renal branching morphogenesis, its been postulated that the final number of nephrons formed is one key clinical factor in the development of hypertension in adulthood. As it has been established that BMPs regulate, in part, renal activity of p38 MAP kinase (p38MAPK) and it has demonstrated that the cytoplasmic protein Neurotrophin Receptor MAGE homologue (NRAGE) augments p38MAPK activation, it was hypothesized that a decrease in the expression of NRAGE during renal branching would result in decreased branching of the UB that correlated with changes in p38MAPK activation. To verify this, the expression of NRAGE was reduced in ex vivo kidney explants cultures using antisense morpholino. Morpholino treated ex vivo kidney explants expression were severely stunted in branching, a trait that was rescued with the addition of exogenous GDNF. Renal explants also demonstrated a precipitous drop in p38MAPK activation that too was reversed in the presence of recombinant GDNF. RNA profiling of NRAGE diminished ex vivo kidney explants resulted in altered expression of GDNF, Ret, BMP7 and BMPRIb mRNAs. Our results suggested that in early kidney development NRAGE might have multiple roles during renal branching morphogenesis through association with both the BMP and GDNF signaling pathways. PMID:19268530

  10. Actin filament curvature biases branching direction

    PubMed Central

    Risca, Viviana I.; Wang, Evan B.; Chaudhuri, Ovijit; Chia, Jia Jun; Geissler, Phillip L.; Fletcher, Daniel A.

    2012-01-01

    Mechanical cues affect many important biological processes in metazoan cells, such as migration, proliferation, and differentiation. Such cues are thought to be detected by specialized mechanosensing molecules linked to the cytoskeleton, an intracellular network of protein filaments that provide mechanical rigidity to the cell and drive cellular shape change. The most abundant such filament, actin, forms branched networks nucleated by the actin-related protein (Arp) 2/3 complex that support or induce membrane protrusions and display adaptive behavior in response to compressive forces. Here we show that filamentous actin serves in a mechanosensitive capacity itself, by biasing the location of actin branch nucleation in response to filament bending. Using an in vitro assay to measure branching from curved sections of immobilized actin filaments, we observed preferential branch formation by the Arp2/3 complex on the convex face of the curved filament. To explain this behavior, we propose a fluctuation gating model in which filament binding or branch nucleation by Arp2/3 occur only when a sufficiently large, transient, local curvature fluctuation causes a favorable conformational change in the filament, and we show with Monte Carlo simulations that this model can quantitatively account for our experimental data. We also show how the branching bias can reinforce actin networks in response to compressive forces. These results demonstrate how filament curvature can alter the interaction of cytoskeletal filaments with regulatory proteins, suggesting that direct mechanotransduction by actin may serve as a general mechanism for organizing the cytoskeleton in response to force. PMID:22308368

  11. Tts, a processive beta-glucosyltransferase of Streptococcus pneumoniae, directs the synthesis of the branched type 37 capsular polysaccharide in Pneumococcus and other gram-positive species.

    PubMed

    Llull, D; Garcia, E; Lopez, R

    2001-06-15

    The type 37 capsule of Streptococcus pneumoniae is a homopolysaccharide built up from repeating units of [beta-d-Glcp-(1-->2)]-beta-d-Glcp-(1-->3). The elements governing the expression of the tts gene, coding for the glucosyltransferase involved in the synthesis of the type 37 pneumococcal capsular polysaccharide, have been studied. Primer extension analysis and functional tests demonstrated the presence of four new transcriptional start points upstream of the previously reported tts promoter (ttsp). Most interesting, three of these transcriptional start points are located in a RUP element thought to be involved in recombinational events (Oggioni, M. R., and Claverys, J. P. (1999) Microbiology 145, 2647-2653). Transformation experiments using either a recombinant plasmid containing the whole transcriptional unit of tts or chromosomal DNA from a type 37 pneumococcus showed that tts is the only gene required to drive the biosynthesis of a type 37 capsule in S. pneumoniae and other Gram-positive bacteria, namely Streptococcus oralis, Streptococcus gordonii, and Bacillus subtilis. The Tts synthase was overproduced in S. pneumoniae and purified as a membrane-associated enzyme. These membrane preparations used UDP-Glc as substrate to catalyze the synthesis of a high molecular weight polysaccharide immunologically identical to the type 37 capsule. In addition, UDP-Gal was also a substrate to produce type 37 polysaccharide since a strong UDP-Glc-4'-epimerase activity is associated to the membrane fraction of S. pneumoniae. These results indicated that Tts has a dual biochemical activity that leads to the synthesis of the branched type 37 polysaccharide.

  12. Thermal Energy Conversion Branch

    NASA Technical Reports Server (NTRS)

    Bielozer, Matthew C.; Schreiber, Jeffrey, G.; Wilson, Scott D.

    2004-01-01

    The Thermal Energy Conversion Branch (5490) leads the way in designing, conducting, and implementing research for the newest thermal systems used in space applications at the NASA Glenn Research Center. Specifically some of the most advanced technologies developed in this branch can be broken down into four main areas: Dynamic Power Systems, Primary Solar Concentrators, Secondary Solar Concentrators, and Thermal Management. Work was performed in the Dynamic Power Systems area, specifically the Stirling Engine subdivision. Today, the main focus of the 5490 branch is free-piston Stirling cycle converters, Brayton cycle nuclear reactors, and heat rejection systems for long duration mission spacecraft. All space exploring devices need electricity to operate. In most space applications, heat energy from radioisotopes is converted to electrical power. The Radioisotope Thermoelectric Generator (RTG) already supplies electricity for missions such as the Cassini Spacecraft. The focus of today's Stirling research at GRC is aimed at creating an engine that can replace the RTG. The primary appeal of the Stirling engine is its high system efficiency. Because it is so efficient, the Stirling engine will significantly reduce the plutonium fuel mission requirements compared to the RTG. Stirling is also being considered for missions such as the lunar/Mars bases and rovers. This project has focused largely on Stirling Engines of all types, particularly the fluidyne liquid piston engine. The fluidyne was developed by Colin D. West. This engine uses the same concepts found in any type of Stirling engine, with the exception of missing mechanical components. All the working components are fluid. One goal was to develop and demonstrate a working Stirling Fluidyne Engine at the 2nd Annual International Energy Conversion Engineering Conference in Providence, Rhode Island.

  13. Combustion Branch Website Development

    NASA Technical Reports Server (NTRS)

    Bishop, Eric

    2004-01-01

    The NASA combustion branch is a leader in developing and applying combustion science to focused aerospace propulsion systems concepts. It is widely recognized for unique facilities, analytical tools, and personnel. In order to better communicate the outstanding research being done in this Branch to the public and other research organization, a more substantial website was desired. The objective of this project was to build an up-to-date site that reflects current research in a usable and attractive manner. In order to accomplish this, information was requested from all researchers in the Combustion branch, on their professional skills and on the current projects. This information was used to fill in the Personnel and Research sections of the website. A digital camera was used to photograph all personnel and these photographs were included in the personnel section as well. The design of the site was implemented using the latest web standards: xhtml and external css stylesheets. This implementation conforms to the guidelines recommended by the w3c. It also helps to ensure that the web site is accessible by disabled users, and complies with Section 508 Federal legislation (which mandates that all Federal websites be accessible). Graphics for the new site were generated using the gimp (www.gimp.org) an open-source graphics program similar to Adobe Photoshop. Also, all graphics on the site were of a reasonable size (less than 20k, most less than 2k) so that the page would load quickly. Technologies such as Macromedia Flash and Javascript were avoided, as these only function on some clients which have the proper software installed or enabled. The website was tested on different platforms with many different browsers to ensure there were no compatibility issues. The website was tested on windows with MS IE 6, MSIE 5 , Netscape 7, Mozilla and Opera. On a Mac, the site was tested with MS IE 5 , Netscape 7 and Safari.

  14. Combustion Branch Website Development

    NASA Technical Reports Server (NTRS)

    Bishop, Eric

    2004-01-01

    The NASA combustion branch is a leader in developing and applying combustion science to focused aerospace propulsion systems concepts. It is widely recognized for unique facilities, analytical tools, and personnel. In order to better communicate the outstanding research being done in this Branch to the public and other research organization, a more substantial website was desired. The objective of this project was to build an up-to-date site that reflects current research in a usable and attractive manner. In order to accomplish this, information was requested from all researchers in the Combustion branch, on their professional skills and on the current projects. This information was used to fill in the Personnel and Research sections of the website. A digital camera was used to photograph all personnel and these photographs were included in the personnel section as well. The design of the site was implemented using the latest web standards: xhtml and external css stylesheets. This implementation conforms to the guidelines recommended by the w3c. It also helps to ensure that the web site is accessible by disabled users, and complies with Section 508 Federal legislation (which mandates that all Federal websites be accessible). Graphics for the new site were generated using the gimp (www.gimp.org) an open-source graphics program similar to Adobe Photoshop. Also, all graphics on the site were of a reasonable size (less than 20k, most less than 2k) so that the page would load quickly. Technologies such as Macromedia Flash and Javascript were avoided, as these only function on some clients which have the proper software installed or enabled. The website was tested on different platforms with many different browsers to ensure there were no compatibility issues. The website was tested on windows with MS IE 6, MSIE 5 , Netscape 7, Mozilla and Opera. On a Mac, the site was tested with MS IE 5 , Netscape 7 and Safari.

  15. Flight Dynamics Analysis Branch

    NASA Technical Reports Server (NTRS)

    Stengle, Tom; Flores-Amaya, Felipe

    2000-01-01

    This report summarizes the major activities and accomplishments carried out by the Flight Dynamics Analysis Branch (FDAB), Code 572, in support of flight projects and technology development initiatives in fiscal year 2000. The report is intended to serve as a summary of the type of support carried out by the FDAB, as well as a concise reference of key accomplishments and mission experience derived from the various mission support roles. The primary focus of the FDAB is to provide expertise in the disciplines of flight dynamics, spacecraft trajectory, attitude analysis, and attitude determination and control. The FDAB currently provides support for missions and technology development projects involving NASA, government, university, and private industry.

  16. Strigolactone inhibition of shoot branching.

    PubMed

    Gomez-Roldan, Victoria; Fermas, Soraya; Brewer, Philip B; Puech-Pagès, Virginie; Dun, Elizabeth A; Pillot, Jean-Paul; Letisse, Fabien; Matusova, Radoslava; Danoun, Saida; Portais, Jean-Charles; Bouwmeester, Harro; Bécard, Guillaume; Beveridge, Christine A; Rameau, Catherine; Rochange, Soizic F

    2008-09-11

    A carotenoid-derived hormonal signal that inhibits shoot branching in plants has long escaped identification. Strigolactones are compounds thought to be derived from carotenoids and are known to trigger the germination of parasitic plant seeds and stimulate symbiotic fungi. Here we present evidence that carotenoid cleavage dioxygenase 8 shoot branching mutants of pea are strigolactone deficient and that strigolactone application restores the wild-type branching phenotype to ccd8 mutants. Moreover, we show that other branching mutants previously characterized as lacking a response to the branching inhibition signal also lack strigolactone response, and are not deficient in strigolactones. These responses are conserved in Arabidopsis. In agreement with the expected properties of the hormonal signal, exogenous strigolactone can be transported in shoots and act at low concentrations. We suggest that endogenous strigolactones or related compounds inhibit shoot branching in plants. Furthermore, ccd8 mutants demonstrate the diverse effects of strigolactones in shoot branching, mycorrhizal symbiosis and parasitic weed interaction.

  17. Branching toughens fibrous networks.

    PubMed

    Koh, C T; Oyen, M L

    2012-08-01

    Fibrous collagenous networks are not only stiff but also tough, due to their complex microstructures. This stiff yet tough behavior is desirable for both medical and military applications but it is difficult to reproduce in engineering materials. While the nonlinear hyperelastic behavior of fibrous networks has been extensively studied, the understanding of toughness is still incomplete. Here, we identify a microstructure mimicking the branched bundles of a natural type I collagen network, in which partially cross-linked long fibers give rise to novel combinations of stiffness and toughness. Finite element analysis shows that the stiffness of fully cross-linked fibrous networks is amplified by increasing the fibril length and cross-link density. However, a trade-off of such stiff networks is reduced toughness. By having partially cross-linked networks with long fibrils, the networks have comparable stiffness and improved toughness as compared to the fully cross-linked networks. Further, the partially cross-linked networks avoid the formation of kinks, which cause fibril rupture during deformation. As a result, the branching allows the networks to have stiff yet tough behavior.

  18. Pen Branch Fault Program

    SciTech Connect

    Price, V.; Stieve, A.L.; Aadland, R.

    1990-09-28

    Evidence from subsurface mapping and seismic reflection surveys at Savannah River Site (SRS) suggests the presence of a fault which displaces Cretaceous through Tertiary (90--35 million years ago) sediments. This feature has been described and named the Pen Branch fault (PBF) in a recent Savannah River Laboratory (SRL) paper (DP-MS-88-219). Because the fault is located near operating nuclear facilities, public perception and federal regulations require a thorough investigation of the fault to determine whether any seismic hazard exists. A phased program with various elements has been established to investigate the PBF to address the Nuclear Regulatory Commission regulatory guidelines represented in 10 CFR 100 Appendix A. The objective of the PBF program is to fully characterize the nature of the PBF (ESS-SRL-89-395). This report briefly presents current understanding of the Pen Branch fault based on shallow drilling activities completed the fall of 1989 (PBF well series) and subsequent core analyses (SRL-ESS-90-145). The results are preliminary and ongoing: however, investigations indicate that the fault is not capable. In conjunction with the shallow drilling, other activities are planned or in progress. 7 refs., 8 figs., 1 tab.

  19. Cravity modulation of the moss Tortula modica branching

    NASA Astrophysics Data System (ADS)

    Khorkavtsiv, Yaroslava; Kit, Nadja

    45-50 (o) to orthotropic stolon axes, and later it decreased negatively gravitropically. The bending of lateral branches of gravitropic protonemata is carried out in two stages: the light induction makes cells metabolically active, but not sensitive to gravitation, while the wall of daughter cell grows perpendicularly to the axes of mother cell and only after that the branches growth direction acquires dependent on gravitation fixed space orientation. Protonemata on light was branched under the angle 45-50 (o) to the axes of the main stolon, that caused similar phenotype of protonemata turf in many moss species. The growth of lateral branches and the set-point angle from the point of view of growth as physical process, is, perhaps, balanced by the action of gravitation and light, and is controlled endogenously by autotropic growth.

  20. Synthesis of branched polysaccharides with tunable degree of branching.

    PubMed

    Ciric, Jelena; Loos, Katja

    2013-03-01

    An in vitro enzyme-catalyzed tandem reaction using the enzymes phosphorylase b from rabbit muscle and Deinococcus geothermalis glycogen branching enzyme (Dg GBE) to obtain branched polyglucans with tunable degree of branching (2% ÷ 13%) is presented. The tunable degree of branching is obtained by varying the reaction conditions such as pH value, the choice of reducing agent and its concentration and reaction time. Linear amylose is formed by the phosphorylase-catalyzed propagation of glucose-1-phosphate while Dg GBE introduces branching points on the α-(1→6) position by relocating short oligosaccharide chains. Our results show that the best way to obtain different degrees of branching with this set of enzymes is by regulation of the reaction time.

  1. A Unifying Theory of Branching Morphogenesis.

    PubMed

    Hannezo, Edouard; Scheele, Colinda L G J; Moad, Mohammad; Drogo, Nicholas; Heer, Rakesh; Sampogna, Rosemary V; van Rheenen, Jacco; Simons, Benjamin D

    2017-09-21

    The morphogenesis of branched organs remains a subject of abiding interest. Although much is known about the underlying signaling pathways, it remains unclear how macroscopic features of branched organs, including their size, network topology, and spatial patterning, are encoded. Here, we show that, in mouse mammary gland, kidney, and human prostate, these features can be explained quantitatively within a single unifying framework of branching and annihilating random walks. Based on quantitative analyses of large-scale organ reconstructions and proliferation kinetics measurements, we propose that morphogenesis follows from the proliferative activity of equipotent tips that stochastically branch and randomly explore their environment but compete neutrally for space, becoming proliferatively inactive when in proximity with neighboring ducts. These results show that complex branched epithelial structures develop as a self-organized process, reliant upon a strikingly simple but generic rule, without recourse to a rigid and deterministic sequence of genetically programmed events. Copyright © 2017 The Author(s). Published by Elsevier Inc. All rights reserved.

  2. Observing Holliday junction branch migration one step at a time

    NASA Astrophysics Data System (ADS)

    Ha, Taekjip

    2004-03-01

    During genetic recombination, two homologous DNA molecules undergo strand exchange to form a four-way DNA (Holliday) junction and the recognition and processing of this species by branch migration and junction resolving enzymes determine the outcome. We have used single molecule fluorescence techniques to study two intrinsic structural dynamics of the Holliday junction, stacking conformer transitions and spontaneous branch migration. Our studies show that the dynamics of branch migration, resolved with one base pair resolution, is determined by the stability of conformers which in turn depends on the local DNA sequences. Therefore, the energy landscape of Holliday junction branch migation is not uniform, but is rugged.

  3. Absolute measurement of hadronic branching fractions of the Ds+ meson.

    PubMed

    Alexander, J P; Berkelman, K; Cassel, D G; Duboscq, J E; Ehrlich, R; Fields, L; Gibbons, L; Gray, R; Gray, S W; Hartill, D L; Heltsley, B K; Hertz, D; Jones, C D; Kandaswamy, J; Kreinick, D L; Kuznetsov, V E; Mahlke-Krüger, H; Mohapatra, D; Onyisi, P U E; Patterson, J R; Peterson, D; Riley, D; Ryd, A; Sadoff, A J; Shi, X; Stroiney, S; Sun, W M; Wilksen, T; Athar, S B; Patel, R; Yelton, J; Rubin, P; Eisenstein, B I; Karliner, I; Mehrabyan, S; Lowrey, N; Selen, M; White, E J; Wiss, J; Mitchell, R E; Shepherd, M R; Besson, D; Pedlar, T K; Cronin-Hennessy, D; Gao, K Y; Hietala, J; Kubota, Y; Klein, T; Lang, B W; Poling, R; Scott, A W; Zweber, P; Dobbs, S; Metreveli, Z; Seth, K K; Tomaradze, A; Libby, J; Powell, A; Wilkinson, G; Ecklund, K M; Love, W; Savinov, V; Lopez, A; Mendez, H; Ramirez, J; Ge, J Y; Miller, D H; Sanghi, B; Shipsey, I P J; Xin, B; Adams, G S; Anderson, M; Cummings, J P; Danko, I; Hu, D; Moziak, B; Napolitano, J; He, Q; Insler, J; Muramatsu, H; Park, C S; Thorndike, E H; Yang, F; Artuso, M; Blusk, S; Khalil, S; Li, J; Mountain, R; Nisar, S; Randrianarivony, K; Sultana, N; Skwarnicki, T; Stone, S; Wang, J C; Zhang, L M; Bonvicini, G; Cinabro, D; Dubrovin, M; Lincoln, A; Rademacker, J; Asner, D M; Edwards, K W; Naik, P; Briere, R A; Ferguson, T; Tatishvili, G; Vogel, H; Watkins, M E; Rosner, J L

    2008-04-25

    The branching fractions of D(s)(+/-) meson decays serve to normalize many measurements of processes involving charm quarks. Using 298 pb(-1) of e(+)e(-) collisions recorded at a center of mass energy of 4.17 GeV, we determine absolute branching fractions for eight D(s)(+/-) decays with a double tag technique. In particular we determine the branching fraction B(D(s)(+)-->K(-)K(+}pi(+))=(5.50+/-0.23+/-0.16)%, where the uncertainties are statistical and systematic, respectively. We also provide partial branching fractions for kinematic subsets of the K(-)K(+)pi(+) decay mode.

  4. The chemical composition of red giants. III. Further CNO isotopic and s-process abundances in thermally pulsing asymptotic giant branch stars

    SciTech Connect

    Smith, V.V.; Lambert, D.L. McDonald Observatory, Austin, TX )

    1990-02-01

    Near-IR and IR spectra are analyzed to obtain elemental and isotopic C, N, and O abundance, iron peak abundances, and heavy element s-process abundances for a sample of M, MS, and S giants. The compositions of the M giants are similar to those of G and K giants and consistent with predictions for giants that have deep convective envelopes and so have experienced the first dredge-up. The MS and S giants have compositions that show the signatures of the third dredge-up that occurs in thermally pulsing AGB stars. The sample shows that C-12, a principal product of the He-burning shell, has been added to the envelopes of MS and S stars. The C-12 enrichment is correlated with a more marked enrichment of the s-process elements that are predicted to be synthesized when a neutron source is ignited in the He-burning shell. The MS and S giants show a higher N abundance than the M giants, attributed to the expected deep mixing that occurs with the onset of the episodic third dredge-up. 122 refs.

  5. Methods and Technologies Branch (MTB)

    Cancer.gov

    The Methods and Technologies Branch focuses on methods to address epidemiologic data collection, study design and analysis, and to modify technological approaches to better understand cancer susceptibility.

  6. Branches in the Everett interpretation

    NASA Astrophysics Data System (ADS)

    Cunningham, Arthur J.

    2014-05-01

    Hugh Everett III describes a quantum measurement as resulting in the "branching" of the quantum state of observer and measured system, with all possible measurement outcomes represented by the ensuing branches of the total quantum state. But Everett does not specify a general rule for decomposing a quantum state into branches, and commentators have long puzzled over how, and even whether, to regard Everett's notion of branching states as physically meaningful. It is common today to appeal to decoherence considerations as a way of giving physical content to the Everettian notion of branches, but these appeals to decoherence are often regarded as considerations foreign to Everett's own approach. This paper contends that this assessment is only half right: though he does not invoke environmental decoherence, Everett does appeal to decoherence considerations, broadly understood, in his treatment of measurement. Careful consideration of his idealized models of measurement, and of the significance he ascribes to the branching of states corresponding to definite measurement outcomes, reveals that his notion of branching refers to a special physical characteristic of elements of a particular decomposition, namely the absence of interference between these component states as a result of the particular dynamics governing the evolution of the system. Characterizations of branching that appeal to the results of modern decoherence theory should therefore be regarded as a natural development of Everett's own physically meaningful conception of branching.

  7. Analysis of long branch extraction and long branch shortening

    PubMed Central

    2010-01-01

    Background Long branch attraction (LBA) is a problem that afflicts both the parsimony and maximum likelihood phylogenetic analysis techniques. Research has shown that parsimony is particularly vulnerable to inferring the wrong tree in Felsenstein topologies. The long branch extraction method is a procedure to detect a data set suffering from this problem so that Maximum Likelihood could be used instead of Maximum Parsimony. Results The long branch extraction method has been well cited and used by many authors in their analysis but no strong validation has been performed as to its accuracy. We performed such an analysis by an extensive search of the branch length search space under two topologies of six taxa, a Felsenstein-like topology and Farris-like topology. We also examine a long branch shortening method. Conclusions The long branch extraction method seems to mask the majority of the search space rendering it ineffective as a detection method of LBA. A proposed alternative, the long branch shortening method, is also ineffective in predicting long branch attraction for all tree topologies. PMID:21047381

  8. Flat, Branched and Split Electrospun Fibers

    NASA Astrophysics Data System (ADS)

    Koombhongse, Sureeporn; Reneker, Darrell H.

    2001-03-01

    The electrospinning process uses electrical force to overcome the force from surface tension. As the electric field increases, the surface of a droplet becomes nearly conical and a charged jet flows from the vertex. The charged jet moves along a straight line for some distance and then begins a spiraling path, which is triggered by a bending instability.[1] The charged jet solidifies as it dries and electrospun nanofibers are collected. The electrospinning process normally produces cylindrical fibers, but sometimes the fibers are flat, branched or split. Flat fibers were electrospun from polystyrene (PS) and poly(2-hydroxyethyl methacrylate) (HEMA) solution. Flat fibers were formed by the collapse of a tube. Branched fibers of HEMA, PS and poly(vinylidene fluoride) were observed. The thinner branch was usually perpendicular to the axis of the primary jet. Branched fibers are formed by a smaller secondary jet ejected from the surface of the primary jet. The charged jet can split apart into two smaller jets to reduce the charge per unit surface area. Split fibers of HEMA, in which two smaller jets run parallel to the axis of the primary jet were observed. 1. D.H. Reneker, A.L. Yarin, H. Fong, and S. Koombhongse, J. Appl. Phys. 87, 4531 (2000).

  9. Modeling branching in cereals.

    PubMed

    Evers, Jochem B; Vos, Jan

    2013-10-10

    Cereals and grasses adapt their structural development to environmental conditions and the resources available. The primary adaptive response is a variable degree of branching, called tillering in cereals. Especially for heterogeneous plant configurations the degree of tillering varies per plant. Functional-structural plant modeling (FSPM) is a modeling approach allowing simulation of the architectural development of individual plants, culminating in the emergent behavior at the canopy level. This paper introduces the principles of modeling tillering in FSPM, using (I) a probability approach, forcing the dynamics of tillering to correspond to measured probabilities. Such models are particularly suitable to evaluate the effect structural variables on system performance. (II) Dose-response curves, representing a measured or assumed response of tillering to an environmental cue. (III) Mechanistic approaches to tillering including control by carbohydrates, hormones, and nutrients. Tiller senescence is equally important for the structural development of cereals as tiller appearance. Little study has been made of tiller senescence, though similar concepts seem to apply as for tiller appearance.

  10. A Branch Meeting in Avon

    ERIC Educational Resources Information Center

    Vaughan, Kathryn; Coles, Alf

    2011-01-01

    The Association of Teachers of Mathematics (ATM) exists for, and is run by, its members. Branch meetings are so much more than the "grass roots" of the association--it can be a powerhouse of inspiration and creativity. In this article, the authors provide commentaries on a recent branch meeting.

  11. A Branch Meeting in Avon

    ERIC Educational Resources Information Center

    Vaughan, Kathryn; Coles, Alf

    2011-01-01

    The Association of Teachers of Mathematics (ATM) exists for, and is run by, its members. Branch meetings are so much more than the "grass roots" of the association--it can be a powerhouse of inspiration and creativity. In this article, the authors provide commentaries on a recent branch meeting.

  12. A positive approach to branching.

    PubMed

    Janssen, Bart J; Drummond, Revel S M; Ledger, Susan E; Snowden, Kimberley C

    2010-04-01

    Plants regulate the development of branches in response to environmental and developmental signals in order to maximize reproductive success. A number of hormone signals are involved in the regulation of branching and both their production and transmission affect axillary meristem outgrowth. With the identification of strigolactones as root-derived branch inhibitors it seems likely that a biochemical pathway starting from a carotenoid and resulting in production of a strigolactone hormone is present in most plants. Our observation that loss of CCD7 or CCD8 also results in production of a promoter of branching from roots shows the branching pathway has multiple levels of control which allows a high degree of sensitivity to subtle differences in environmental and developmental signals.

  13. A branching process model for sand avalanches

    SciTech Connect

    Garcia-Pelayo, R.; Salazar, I.; Schieve, W.C. )

    1993-07-01

    An analytically solvable model for sand avalanches of noninteracting grains of sand, based on the Chapman-Kolmogorov equations, is presented. For a single avalanche, distributions of lifetimes, sizes of overflows and avalanches, and correlation functions are calculated. Some of these are exponentials, some are power laws. Spatially homogeneous distributions of avalanches are also studied. Computer simulations of avalanches of interacting grains of sand are compared to the solutions to the Chapman-Kolmogorov equations. It is found that within the range of parameters explored in the simulation, the approximation of noninteracting grains of sand is a good one. 20 refs., 4 figs.

  14. Regenerative Sampling and Monotonic Branching Processes.

    DTIC Science & Technology

    1986-05-01

    clinical study of a potentially life-saving medical procedure because of its tendency to put more patients on the better treatment (Bartlett et al...Choose s such that s > 1 and r < s < p. Then by Minkowski and Holder inequalities (43) [lT n1 -u-mT nSJi/S zn-i E (E( Zk - 1 J jZk-mZkl sji/s k1 n-i...Zi < kl( 4j jS ZE Zk ’-1 IP]i/p Let q =asp/(p-s). Then by Lemma 1, for some 0 < (x < 1 Zkiq E(E((’ ’-1’LL2)’IF ( Zn~ Z n_2) n-l n-1n-2 (44) E (k) E(( n

  15. Nature of branching in disordered materials

    NASA Astrophysics Data System (ADS)

    Kulkarni, Amit S.

    reflect different features of the global structure, and it is categorically shown that this dimensional analysis results in effective structure characterization of these materials. Small-angle scattering of x-rays and neutrons can be used to quantify branch content and characterize the structure, through application of concepts native to fractal geometry. The application of the scaling model to nano-particulate aggregates yields quantitative information regarding the structure of these materials. In-situ small and ultra small angle x-ray scattering data collected on fumed silica and soot particles is presented in Chapter II. These measurements were performed at Advanced Photon Source, Argonne National Laboratory, UNICAT beam-line and the European Synchrotron Radiation Facility, Grenoble, France, ID2 beam-line. The dimensional analysis is successful in not only giving an average snap-shot of the nano-particulate aggregates, but also yields information regarding the growth processes involved in the complex pyrolysis technique of synthesizing these materials. In case of macromolecular systems, the minimum path dimension, dmin, is shown to reflect the thermodynamics of the system. This is categorically established in Chapter III on hyperbranched polymers, where the scaling model accurately predicts the good-solvent to theta-condition transition in these highly branched polymers with increasing molar mass. The scaling model is applied to the long standing problem of quantifying long chain branching in polyethylene in Chapter IV. Small angle neutron scattering data on dilute solutions of polyethylene were obtained at the Intense Pulsed Neutron Source (SAND beam-line); NIST center for Neutron Scattering (NG3 beam-line); and Los Alamos Neutron Scattering Center (LQD beam-line). This work, for the first time in literature, reports the length of a long chain branch in polyethylene in terms of the average molar mass of the branches, and the average number of carbon atoms in the long

  16. Branch strategies - Modeling and optimization

    NASA Technical Reports Server (NTRS)

    Dubey, Pradeep K.; Flynn, Michael J.

    1991-01-01

    The authors provide a common platform for modeling different schemes for reducing the branch-delay penalty in pipelined processors as well as evaluating the associated increased instruction bandwidth. Their objective is twofold: to develop a model for different approaches to the branch problem and to help select an optimal strategy after taking into account additional i-traffic generated by branch strategies. The model presented provides a flexible tool for comparing different branch strategies in terms of the reduction it offers in average branch delay and also in terms of the associated cost of wasted instruction fetches. This additional criterion turns out to be a valuable consideration in choosing between two strategies that perform almost equally. More importantly, it provides a better insight into the expected overall system performance. Simple compiler-support-based low-implementation-cost strategies can be very effective under certain conditions. An active branch prediction scheme based on loop buffers can be as competitive as a branch-target-buffer based strategy.

  17. Branched Nanowire Architectures for Compact Power Sources

    DTIC Science & Technology

    2009-04-13

    down to the level of single bacteria . First, methods for the predictable and controlled synthesis of branched nanaowires consisting of well-defined...focused on controlled synthesis and characterization of nanowire building blocks that can function as probes of fundamental biofuel cell processes. the...fabrication of new nanoscale electrodes enabling studies of microbial fuel cells down to the level of single bacteria . The results from these studies have

  18. Asymptotics of Simple Branching Populations

    NASA Astrophysics Data System (ADS)

    Huillet, Thierry; Kłopotowski, Andrzej; Porzio, Anna

    1995-09-01

    In this paper we study a simple deterministic tree structure: an initial individual generates a finite number of offspring, each of which has given integer valued lifetime, iterating the same procedure when dying. Three asymptotic distributions of this asynchronous deterministic branching procedure are considered: the generation distribution, the ability of individuals to generate offspring and the age distribution. Thermodynamic formalism is then developped to reveal the multifractal nature of the mass splitting associated to our process. On considère l'itération d'une structure déterministe arborescente selon laquelle un ancêtre engendre un nombre fini de descendants dont la durée de vie (à valeurs entières) est donnée. Dans un premier temps on s'intéresse aux trois distributions asymptotiques suivantes : répartition des générations, aptitude à engendrer des descendants et répartition selon l'âge. Ensuite nous développons le formalisme thermodynamique pour mettre en évidence le caractère multifractal de la scission d'une masse unitaire associée à cette arborescence.

  19. Electrical communication in branching arterial networks.

    PubMed

    Tran, Cam Ha T; Vigmond, Edward J; Goldman, Daniel; Plane, France; Welsh, Donald G

    2012-09-15

    Electrical communication and its role in blood flow regulation are built on an examination of charge movement in single, isolated vessels. How this process behaves in broader arterial networks remains unclear. This study examined the nature of electrical communication in arterial structures where vessel length and branching were varied. Analysis began with the deployment of an existing computational model expanded to form a variable range of vessel structures. Initial simulations revealed that focal endothelial stimulation generated electrical responses that conducted robustly along short unbranched vessels and to a lesser degree lengthened arteries or branching structures retaining a single branch point. These predictions matched functional observations from hamster mesenteric arteries and support the idea that an increased number of vascular cells attenuate conduction by augmenting electrical load. Expanding the virtual network to 31 branches revealed that electrical responses increasingly ascended from fifth- to first-order arteries when the number of stimulated distal vessels rose. This property enabled the vascular network to grade vasodilation and network perfusion as revealed through blood flow modeling. An elevation in endothelial-endothelial coupling resistance, akin to those in sepsis models, compromised this ascension of vasomotor/perfusion responses. A comparable change was not observed when the endothelium was focally disrupted to mimic disease states including atherosclerosis. In closing, this study highlights that vessel length and branching play a role in setting the conduction of electrical phenomenon along resistance arteries and within networks. It also emphasizes that modest changes in endothelial function can, under certain scenarios, impinge on network responsiveness and blood flow control.

  20. Developmental Programming of Branching Morphogenesis in the Kidney.

    PubMed

    Sampogna, Rosemary V; Schneider, Laura; Al-Awqati, Qais

    2015-10-01

    The kidney developmental program encodes the intricate branching and organization of approximately 1 million functional units (nephrons). Branching regulation is poorly understood, as is the source of a 10-fold variation in nephron number. Notably, low nephron count increases the risk for developing hypertension and renal failure. To better understand the source of this variation, we analyzed the complete gestational trajectory of mouse kidney development. We constructed a computerized architectural map of the branching process throughout fetal life and found that organogenesis is composed of two distinct developmental phases, each with stage-specific rate and morphologic parameters. The early phase is characterized by a rapid acceleration in branching rate and by branching divisions that repeat with relatively reproducible morphology. The latter phase, however, is notable for a significantly decreased yet constant branching rate and the presence of nonstereotyped branching events that generate progressive variability in tree morphology until birth. Our map identifies and quantitates the contribution of four developmental mechanisms that guide organogenesis: growth, patterning, branching rate, and nephron induction. When applied to organs that developed under conditions of malnutrition or in the setting of growth factor mutation, our normative map provided an essential link between kidney architecture and the fundamental morphogenetic mechanisms that guide development. This morphogenetic map is expected to find widespread applications and help identify modifiable targets to prevent developmental programming of common diseases. Copyright © 2015 by the American Society of Nephrology.

  1. Novel side branch ostial stent.

    PubMed

    Chen, Shao-Liang; Lv, Shu-Zheng; Kwan, Tak W

    2009-04-01

    Bifurcation lesions are technically challenging and plagued by a high incidence of restenosis, especially at the side branch orifice, which results in a more frequent need for revascularization during the follow-up period. This report discusses two clinical experiences with a novel side branch ostial stent, the BIGUARD stent, designed for the treatment of bifurcation lesions; procedural success with no in-hospital complications was observed in types IVb and Ia lesions.

  2. Structural Mechanics and Dynamics Branch

    NASA Technical Reports Server (NTRS)

    Stefko, George

    2003-01-01

    The 2002 annual report of the Structural Mechanics and Dynamics Branch reflects the majority of the work performed by the branch staff during the 2002 calendar year. Its purpose is to give a brief review of the branch s technical accomplishments. The Structural Mechanics and Dynamics Branch develops innovative computational tools, benchmark experimental data, and solutions to long-term barrier problems in the areas of propulsion aeroelasticity, active and passive damping, engine vibration control, rotor dynamics, magnetic suspension, structural mechanics, probabilistics, smart structures, engine system dynamics, and engine containment. Furthermore, the branch is developing a compact, nonpolluting, bearingless electric machine with electric power supplied by fuel cells for future "more electric" aircraft. An ultra-high-power-density machine that can generate projected power densities of 50 hp/lb or more, in comparison to conventional electric machines, which generate usually 0.2 hp/lb, is under development for application to electric drives for propulsive fans or propellers. In the future, propulsion and power systems will need to be lighter, to operate at higher temperatures, and to be more reliable in order to achieve higher performance and economic viability. The Structural Mechanics and Dynamics Branch is working to achieve these complex, challenging goals.

  3. Quantitative macroinvertebrate survey of Pen Branch and Indian Grave Branch

    SciTech Connect

    Not Available

    1989-02-01

    A total of 80 species were collected at all sites on Pen Branch and Indian Grave Branch during the 28 day period for colonization of the multiplate artificial substrate samplers. The two upstream sites demonstrated the highest species richness. During the sampling interval a release of significant proportion entered Indian Grave Branch, affecting all downstream sites. This effect was most severe at sites 3, 4, and 7, apparently resulting in heavy scouring of the multiplate samplers. Nevertheless, much colonization did occur at sites 3 and 4, with hydropsychid caddisflies, blackflies and midges predominant. At sites 5 and 6 a greater degree of recovery was noted, due to the lessened scouring in the broad floodplain. These downstream sites had significant numbers of mayflies along with the numerous midges. Considered overall, colonization during the period since the K Reactor has ceased releasing thermal effluent into Pen Branch and Indian Grave Branch has been substantial, introducing a substantial proportion of the species known from other nearby streams. 29 tabs.

  4. Fort Collins Science Center Ecosystem Dynamics Branch

    USGS Publications Warehouse

    Wilson, Jim; Melcher, C.; Bowen, Z.

    2009-01-01

    Complex natural resource issues require understanding a web of interactions among ecosystem components that are (1) interdisciplinary, encompassing physical, chemical, and biological processes; (2) spatially complex, involving movements of animals, water, and airborne materials across a range of landscapes and jurisdictions; and (3) temporally complex, occurring over days, weeks, or years, sometimes involving response lags to alteration or exhibiting large natural variation. Scientists in the Ecosystem Dynamics Branch of the U.S. Geological Survey, Fort Collins Science Center, investigate a diversity of these complex natural resource questions at the landscape and systems levels. This Fact Sheet describes the work of the Ecosystems Dynamics Branch, which is focused on energy and land use, climate change and long-term integrated assessments, herbivore-ecosystem interactions, fire and post-fire restoration, and environmental flows and river restoration.

  5. Phylogenomic analysis of glycogen branching and debranching enzymatic duo.

    PubMed

    Zmasek, Christian M; Godzik, Adam

    2014-08-23

    Branched polymers of glucose are universally used for energy storage in cells, taking the form of glycogen in animals, fungi, Bacteria, and Archaea, and of amylopectin in plants. Some enzymes involved in glycogen and amylopectin metabolism are similarly conserved in all forms of life, but some, interestingly, are not. In this paper we focus on the phylogeny of glycogen branching and debranching enzymes, respectively involved in introducing and removing of the α(1-6) bonds in glucose polymers, bonds that provide the unique branching structure to glucose polymers. We performed a large-scale phylogenomic analysis of branching and debranching enzymes in over 400 completely sequenced genomes, including more than 200 from eukaryotes. We show that branching and debranching enzymes can be found in all kingdoms of life, including all major groups of eukaryotes, and thus were likely to have been present in the last universal common ancestor (LUCA) but have been lost in seemingly random fashion in numerous single-celled eukaryotes. We also show how animal branching and debranching enzymes evolved from their LUCA ancestors by acquiring additional domains. Furthermore, we show that enzymes commonly perceived as orthologous, such as human branching enzyme GBE1 and E. coli branching enzyme GlgB, are in fact related by a gene duplication and consequently paralogous. Despite being usually associated with animal liver glycogen and plant starch, energy storage in the form of branched glucose polymers is clearly an ancient process and has probably been present in the last universal common ancestor of all present life. The evolution of the enzymes enabling this form of energy storage is more complex than previously thought and illustrates the need for explicit phylogenomic analysis in the study of even seemingly "simple" metabolic enzymes. Patterns of conservation in the evolution of the glycogen/starch branching and debranching enzymes hint at some as yet unknown mechanisms, as

  6. Phenomenological picture of fluctuations in branching random walks.

    PubMed

    Mueller, A H; Munier, S

    2014-10-01

    We propose a picture of the fluctuations in branching random walks, which leads to predictions for the distribution of a random variable that characterizes the position of the bulk of the particles. We also interpret the 1/sqrt[t] correction to the average position of the rightmost particle of a branching random walk for large times t≫1, computed by Ebert and Van Saarloos, as fluctuations on top of the mean-field approximation of this process with a Brunet-Derrida cutoff at the tip that simulates discreteness. Our analytical formulas successfully compare to numerical simulations of a particular model of a branching random walk.

  7. Phenomenological picture of fluctuations in branching random walks

    NASA Astrophysics Data System (ADS)

    Mueller, A. H.; Munier, S.

    2014-10-01

    We propose a picture of the fluctuations in branching random walks, which leads to predictions for the distribution of a random variable that characterizes the position of the bulk of the particles. We also interpret the 1 /√{t } correction to the average position of the rightmost particle of a branching random walk for large times t ≫1 , computed by Ebert and Van Saarloos, as fluctuations on top of the mean-field approximation of this process with a Brunet-Derrida cutoff at the tip that simulates discreteness. Our analytical formulas successfully compare to numerical simulations of a particular model of a branching random walk.

  8. LETTER TO THE EDITOR: Quantum field theory and phylogenetic branching

    NASA Astrophysics Data System (ADS)

    Jarvis, P. D.; Bashford, J. D.

    2001-12-01

    A calculational framework is proposed for phylogenetics, using nonlocal quantum field theories in hypercubic geometry. Quadratic terms in the Hamiltonian give the underlying Markov dynamics, while higher degree terms represent branching events. The spatial dimension L is the number of leaves of the evolutionary tree under consideration. Momentum conservation modulo ←1 scattering corresponds to tree edge labelling using binary L-vectors. The bilocal quadratic term allows for momentum-dependent rate constants - only the tree or trees compatible with selected nonzero edge rates contribute to the branching probability distribution. Applications to models of evolutionary branching processes are discussed.

  9. Probing active electron transfer branch in photosystem I reaction center.

    NASA Astrophysics Data System (ADS)

    Savikhin, Sergei; Dashdorj, Naranbaatar; Xu, Wu; Martinsson, Peter; Chitnis, Parag

    2003-03-01

    Complimentary point mutations were introduced at the primary electron acceptor sites in A and B branches of the photosystem I (PS I) reaction center (RC) from Synechocystis sp. PCC 6803 and their effect on the kinetics of the electron transfer process was studied by means of ultrafast pump-probe spectroscopy. The results indicate that in these species the electron transfer occurs primarily along the A-branch. Previous optical experiments on PS I complexes from Chlorella sorokiniana demonstrated that both branches of RC are equally active. That suggests that the directionality of electron transfer in PS I is species dependent.

  10. Photovoltaic measurements and performance branch

    NASA Astrophysics Data System (ADS)

    Asher, S. E.; Dippo, P.

    1990-05-01

    The Photovoltaic (PV) Measurements and Performance Branch of the Solar Energy Research Institute (SERI) provides comprehensive PV materials, device and component characterization, measurement, fabrication, and modeling research and support for the international PV research community in the context of the U.S. Department of Energy's PV m goals. The progress of the Branch is summarized. The seven technical sections present a succinct overview of the capabilities and accomplishments of each group in the Branch. The Branch is comprised of the following groups; Surface and Interface Analysis, Materials Characterization, Device Development, Electro-Optical Characterization, Cell Performance, Advanced Module Testing and Performance, and Surface and Interface Modification and Stability. The main research projects completed in FY 1989 are highlighted including measurements and tests of PV materials, cells, submodules and modules. The report contains a comprehensive bibliography of the more than 80 branch-originated journal and conference publications which were authored in collaboration with, or in support of, approximately 130 university, industrial, government, and in-house research groups.

  11. Optimization and phenotype allocation.

    PubMed

    Jost, Jürgen; Wang, Ying

    2014-01-01

    We study the phenotype allocation problem for the stochastic evolution of a multitype population in a random environment. Our underlying model is a multitype Galton–Watson branching process in a random environment. In the multitype branching model, different types denote different phenotypes of offspring, and offspring distributions denote the allocation strategies. Two possible optimization targets are considered: the long-term growth rate of the population conditioned on nonextinction, and the extinction probability of the lineage. In a simple and biologically motivated case, we derive an explicit formula for the long-term growth rate using the random Perron–Frobenius theorem, and we give an approximation to the extinction probability by a method similar to that developed by Wilkinson. Then we obtain the optimal strategies that maximize the long-term growth rate or minimize the approximate extinction probability, respectively, in a numerical example. It turns out that different optimality criteria can lead to different strategies.

  12. Fault Branching and Rupture Directivity

    NASA Astrophysics Data System (ADS)

    Dmowska, R.; Rice, J. R.; Kame, N.

    2002-12-01

    Can the rupture directivity of past earthquakes be inferred from fault geometry? Nakata et al. [J. Geogr., 1998] propose to relate the observed surface branching of fault systems with directivity. Their work assumes that all branches are through acute angles in the direction of rupture propagation. However, in some observed cases rupture paths seem to branch through highly obtuse angles, as if to propagate ``backwards". Field examples of that are as follows: (1) Landers 1992. When crossing from the Johnson Valley to the Homestead Valley (HV) fault via the Kickapoo (Kp) fault, the rupture from Kp progressed not just forward onto the northern stretch of the HV fault, but also backwards, i.e., SSE along the HV [Sowers et al., 1994, Spotila and Sieh, 1995, Zachariasen and Sieh, 1995, Rockwell et al., 2000]. Measurements of surface slip along that backward branch, a prominent feature of 4 km length, show right-lateral slip, decreasing towards the SSE. (2) At a similar crossing from the HV to the Emerson (Em) fault, the rupture progressed backwards along different SSE splays of the Em fault [Zachariasen and Sieh, 1995]. (3). In crossing from the Em to Camp Rock (CR) fault, again, rupture went SSE on the CR fault. (4). Hector Mine 1999. The rupture originated on a buried fault without surface trace [Li et al., 2002; Hauksson et al., 2002] and progressed bilaterally south and north. In the south it met the Lavic Lake (LL) fault and progressed south on it, but also progressed backward, i.e. NNW, along the northern stretch of the LL fault. The angle between the buried fault and the northern LL fault is around -160o, and that NNW stretch extends around 15 km. The field examples with highly obtuse branch angles suggest that there may be no simple correlation between fault geometry and rupture directivity. We propose that an important distinction is whether those obtuse branches actually involved a rupture path which directly turned through the obtuse angle (while continuing

  13. 30 CFR 56.6403 - Branch circuits.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Branch circuits. 56.6403 Section 56.6403... Blasting § 56.6403 Branch circuits. (a) If electric blasting includes the use of branch circuits, each branch shall be equipped with a safety switch or equivalent method to isolate the circuits to be used. (b...

  14. 30 CFR 57.6403 - Branch circuits.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Branch circuits. 57.6403 Section 57.6403... Blasting-Surface and Underground § 57.6403 Branch circuits. (a) If electric blasting includes the use of branch circuits, each branch shall be equipped with a safety switch or equivalent method to isolate the...

  15. 30 CFR 56.6403 - Branch circuits.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Branch circuits. 56.6403 Section 56.6403... Blasting § 56.6403 Branch circuits. (a) If electric blasting includes the use of branch circuits, each branch shall be equipped with a safety switch or equivalent method to isolate the circuits to be used. (b...

  16. 30 CFR 56.6403 - Branch circuits.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Branch circuits. 56.6403 Section 56.6403... Blasting § 56.6403 Branch circuits. (a) If electric blasting includes the use of branch circuits, each branch shall be equipped with a safety switch or equivalent method to isolate the circuits to be used. (b...

  17. 30 CFR 57.6403 - Branch circuits.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Branch circuits. 57.6403 Section 57.6403... Blasting-Surface and Underground § 57.6403 Branch circuits. (a) If electric blasting includes the use of branch circuits, each branch shall be equipped with a safety switch or equivalent method to isolate the...

  18. 30 CFR 57.6403 - Branch circuits.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Branch circuits. 57.6403 Section 57.6403... Blasting-Surface and Underground § 57.6403 Branch circuits. (a) If electric blasting includes the use of branch circuits, each branch shall be equipped with a safety switch or equivalent method to isolate the...

  19. 30 CFR 57.6403 - Branch circuits.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Branch circuits. 57.6403 Section 57.6403... Blasting-Surface and Underground § 57.6403 Branch circuits. (a) If electric blasting includes the use of branch circuits, each branch shall be equipped with a safety switch or equivalent method to isolate the...

  20. 30 CFR 56.6403 - Branch circuits.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Branch circuits. 56.6403 Section 56.6403... Blasting § 56.6403 Branch circuits. (a) If electric blasting includes the use of branch circuits, each branch shall be equipped with a safety switch or equivalent method to isolate the circuits to be used. (b...

  1. 30 CFR 56.6403 - Branch circuits.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Branch circuits. 56.6403 Section 56.6403... Blasting § 56.6403 Branch circuits. (a) If electric blasting includes the use of branch circuits, each branch shall be equipped with a safety switch or equivalent method to isolate the circuits to be used. (b...

  2. 30 CFR 57.6403 - Branch circuits.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Branch circuits. 57.6403 Section 57.6403... Blasting-Surface and Underground § 57.6403 Branch circuits. (a) If electric blasting includes the use of branch circuits, each branch shall be equipped with a safety switch or equivalent method to isolate the...

  3. 17 CFR 166.4 - Branch offices.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 17 Commodity and Securities Exchanges 1 2010-04-01 2010-04-01 false Branch offices. 166.4 Section... RULES § 166.4 Branch offices. Each branch office of each Commission registrant must use the name of the.... The act, omission or failure of any person acting for the branch office, within the scope of...

  4. Double-branched vortex generator

    NASA Technical Reports Server (NTRS)

    Cantwell, E. R.; Westphal, R. V.; Mehta, R. D.

    1985-01-01

    In order to assess the suitability of using a double branched vortex generator in parametric studies involving vortex interactions, an experimental study of the main vortex and secondary flows produced by a double branched vortex generator was conducted in a 20-by-40 cm indraft wind tunnel. Measurements of the cross flow velocities were made with a five hole pressure probe from which vorticity contours and vortex parameters were derived. The results showed that the optimum configuration consisted of chord extensions with the absence of a centerbody.

  5. The effect of thermal pressurization on dynamic fault branching

    NASA Astrophysics Data System (ADS)

    Urata, Yumi; Hok, Sébastien; Fukuyama, Eiichi; Madariaga, Raúl

    2014-02-01

    We numerically investigate the effect of thermal pressurization (TP) on fault branch behaviour during dynamic rupture propagation, a situation likely to occur during large earthquakes at subduction interfaces. We consider a 2-D mode II (in-plane) rupture in an infinite medium that propagates spontaneously along a planar main fault and encounters an intersection with a pre-existing branching fault. The fault system is subjected to uniform external stresses. We adopt the values used by Kame et al. We use the 2-D boundary integral equation method and the slip-weakening friction law with a Coulomb failure criterion, allowing the effective normal stress to vary as pore pressure changes due to TP. We reveal that TP can alter rupture propagation paths when the dip angle of the main fault is small. The rupture propagation paths depend on the branching angle when TP is not in effect on either of the faults, as described by Kame et al. However, the dynamic rupture processes are controlled more by TP than by the branching angle. When TP is in effect on the main fault only, the rupture propagates along the main fault. It propagates along the branch when TP is in effect on both faults. Finally, we considered the case where there is a free surface above the branch fault system. In this case, the rupture can propagate along both faults because of interaction between the free surface and the branch fault, in addition to TP on the main fault.

  6. Risk Factor Assessment Branch (RFAB)

    Cancer.gov

    The Risk Factor Assessment Branch (RFAB) focuses on the development, evaluation, and dissemination of high-quality risk factor metrics, methods, tools, technologies, and resources for use across the cancer research continuum, and the assessment of cancer-related risk factors in the population.

  7. NCI: DCTD: Biometric Research Branch

    Cancer.gov

    The Biometric Research Branch (BRB) is the statistical and biomathematical component of the Division of Cancer Treatment, Diagnosis and Centers (DCTDC). Its members provide statistical leadership for the national and international research programs of the division in developmental therapeutics, developmental diagnostics, diagnostic imaging and clinical trials.

  8. NCI: DCTD: Biometric Research Branch

    Cancer.gov

    The Biometric Research Branch (BRP) is the statistical and biomathematical component of the Division of Cancer Treatment, Diagnosis and Centers (DCTDC). Its members provide statistical leadership for the national and international research programs of the division in developmental therapeutics, developmental diagnostics, diagnostic imaging and clinical trials.

  9. 76 FR 13272 - Branch Offices

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-03-10

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF THE TREASURY Office of Thrift Supervision Branch Offices AGENCY: Office of Thrift Supervision (OTS), Treasury. ACTION... 1995, 44 U.S.C. 3507. The Office of Thrift Supervision within the Department of the Treasury...

  10. Multiple pathways regulate shoot branching

    PubMed Central

    Rameau, Catherine; Bertheloot, Jessica; Leduc, Nathalie; Andrieu, Bruno; Foucher, Fabrice; Sakr, Soulaiman

    2015-01-01

    Shoot branching patterns result from the spatio-temporal regulation of axillary bud outgrowth. Numerous endogenous, developmental and environmental factors are integrated at the bud and plant levels to determine numbers of growing shoots. Multiple pathways that converge to common integrators are most probably involved. We propose several pathways involving not only the classical hormones auxin, cytokinins and strigolactones, but also other signals with a strong influence on shoot branching such as gibberellins, sugars or molecular actors of plant phase transition. We also deal with recent findings about the molecular mechanisms and the pathway involved in the response to shade as an example of an environmental signal controlling branching. We propose the TEOSINTE BRANCHED1, CYCLOIDEA, PCF transcription factor TB1/BRC1 and the polar auxin transport stream in the stem as possible integrators of these pathways. We finally discuss how modeling can help to represent this highly dynamic system by articulating knowledges and hypothesis and calculating the phenotype properties they imply. PMID:25628627

  11. Legislative Branch Appropriations Act, 2010

    THOMAS, 111th Congress

    Rep. Wasserman Schultz, Debbie [D-FL-20

    2009-06-17

    10/01/2009 Became Public Law No: 111-68. (TXT | PDF) (All Actions) Notes: Division A is the Legislative Branch Appropriations Act, 2010. Division B is the Continuing Appropriations Resolution, 2010. Tracker: This bill has the status Became LawHere are the steps for Status of Legislation:

  12. NCI: DCTD: Biometric Research Branch

    Cancer.gov

    The Biometric Research Branch (BRB) is the statistical and biomathematical component of the Division of Cancer Treatment, Diagnosis and Centers (DCTDC). Its members provide statistical leadership for the national and international research programs of the division in developmental therapeutics, developmental diagnostics, diagnostic imaging and clinical trials.

  13. Branching of keratin intermediate filaments.

    PubMed

    Nafeey, Soufi; Martin, Ines; Felder, Tatiana; Walther, Paul; Felder, Edward

    2016-06-01

    Keratin intermediate filaments (IFs) are crucial to maintain mechanical stability in epithelial cells. Since little is known about the network architecture that provides this stiffness and especially about branching properties of filaments, we addressed this question with different electron microscopic (EM) methods. Using EM tomography of high pressure frozen keratinocytes, we investigated the course of several filaments in a branching of a filament bundle. Moreover we found several putative bifurcations in individual filaments. To verify our observation we also visualized the keratin network in detergent extracted keratinocytes with scanning EM. Here bifurcations of individual filaments could unambiguously be identified additionally to bundle branchings. Interestingly, identical filament bifurcations were also found in purified keratin 8/18 filaments expressed in Escherichia coli which were reassembled in vitro. This excludes that an accessory protein contributes to the branch formation. Measurements of the filament cross sectional areas showed various ratios between the three bifurcation arms. This demonstrates that intermediate filament furcation is very different from actin furcation where an entire new filament is attached to an existing filament. Instead, the architecture of intermediate filament bifurcations is less predetermined and hence consistent with the general concept of IF formation. Copyright © 2016 Elsevier Inc. All rights reserved.

  14. Legislative Branch Appropriations Act, 2010

    THOMAS, 111th Congress

    Rep. Wasserman Schultz, Debbie [D-FL-20

    2009-06-17

    10/01/2009 Became Public Law No: 111-68. (TXT | PDF) (All Actions) Notes: Division A is the Legislative Branch Appropriations Act, 2010. Division B is the Continuing Appropriations Resolution, 2010. Tracker: This bill has the status Became LawHere are the steps for Status of Legislation:

  15. National Zoological Park Branch Library.

    ERIC Educational Resources Information Center

    Kenyon, Kay A.

    1988-01-01

    Describes the functions of the National Zoological Park Branch of the Smithsonian Institution Libraries, which is dedicated to supporting the special information needs of the zoo. Topics covered include the library's history, collection, programs, services, future plans, and relations with other zoo libraries. (two references) (Author/CLB)

  16. Legislative Branch Appropriations Act, 2010

    THOMAS, 111th Congress

    Rep. Wasserman Schultz, Debbie [D-FL-20

    2009-06-17

    10/01/2009 Became Public Law No: 111-68. (PDF) (All Actions) Notes: Division A is the Legislative Branch Appropriations Act, 2010. Division B is the Continuing Appropriations Resolution, 2010. Tracker: This bill has the status Became LawHere are the steps for Status of Legislation:

  17. On extreme events for non-spatial and spatial branching Brownian motions

    NASA Astrophysics Data System (ADS)

    Avan, Jean; Grosjean, Nicolas; Huillet, Thierry

    2015-04-01

    We study the impact of having a non-spatial branching mechanism with infinite variance on some parameters (height, width and first hitting time) of an underlying Bienaymé-Galton-Watson branching process. Aiming at providing a comparative study of the spread of an epidemics whose dynamics is given by the modulus of a branching Brownian motion (BBM) we then consider spatial branching processes in dimension d, not necessarily integer. The underlying branching mechanism is either a binary branching model or one presenting infinite variance. In particular we evaluate the chance p(x) of being hit if the epidemics started away at distance x. We compute the large x tail probabilities of this event, both when the branching mechanism is regular and when it exhibits very large fluctuations.

  18. Developmental morphology of branching flowers in Nymphaea prolifera.

    PubMed

    Grob, Valentin; Moline, Philip; Pfeifer, Evelin; Novelo, Alejandro R; Rutishauser, Rolf

    2006-11-01

    Nymphaea and Nuphar (Nymphaeaceae) share an extra-axillary mode of floral inception in the shoot apical meristem (SAM). Some leaf sites along the ontogenetic spiral are occupied by floral primordia lacking a subtending bract. This pattern of flower initiation in leaf sites is repeated inside branching flowers of Nymphaea prolifera (Central and South America). Instead of fertile flowers this species usually produces sterile tuberiferous flowers that act as vegetative propagules. N. prolifera changes the meristem identity from reproductive to vegetative or vice versa repeatedly. Each branching flower first produces some perianth-like leaves, then it switches back to the vegetative meristem identity of the SAM with the formation of foliage leaves and another set of branching flowers. This process is repeated up to three times giving rise to more than 100 vegetative propagules. The developmental morphology of the branching flowers of N. prolifera is described using both microtome sections and scanning electron microscopy.

  19. Bundle Branch Reentrant Ventricular Tachycardia

    PubMed Central

    Mazur, Alexander; Kusniec, Jairo; Strasberg, Boris

    2005-01-01

    Bundle branch reentrant (BBR) tachycardia is an uncommon form of ventricular tachycardia (VT) incorporating both bundle branches into the reentry circuit. The arrhythmia is usually seen in patients with an acquired heart disease and significant conduction system impairment, although patients with structurally normal heart have been described. Surface ECG in sinus rhythm (SR) characteristically shows intraventricular conduction defects. Patients typically present with presyncope, syncope or sudden death because of VT with fast rates frequently above 200 beats per minute. The QRS morphology during VT is a typical bundle branch block pattern, usually left bundle branch block, and may be identical to that in SR. Prolonged His-ventricular (H-V) interval in SR is found in the majority of patients with BBR VT, although some patients may have the H-V interval within normal limits. The diagnosis of BBR VT is based on electrophysiological findings and pacing maneuvers that prove participation of the His- Purkinje system in the tachycardia mechanism. Radiofrequency catheter ablation of a bundle branch can cure BBR VT and is currently regarded as the first line therapy. The technique of choice is ablation of the right bundle. The reported incidence of clinically significant conduction system impairment requiring implantation of a permanent pacemaker varies from 0% to 30%. Long-term outcome depends on the underlying cardiac disease. Patients with poor systolic left ventricular function are at risk of sudden death or death from progressive heart failure despite successful BBR VT ablation and should be considered for an implantable cardiovertor-defibrillator. PMID:16943949

  20. To branch or not to branch: Numerical modeling of dynamically branching faults

    NASA Astrophysics Data System (ADS)

    Dedontney, N. L.; Templeton Barrett, E. L.; Rice, J. R.; Dmowska, R.

    2009-12-01

    Branched fault geometries, and branched rupture paths, occur in strike-slip as well as dip-slip settings [e.g., Poliakov et al., JGR, 2002; Kame et al., JGR, 2003]. The Wenchuan earthquake illustrates such a branched geometry [Hubbard and Shaw, 2009] in a fold and thrust belt, and surface ruptures provide constraints on which faults were activated co-seismically. Additionally, a branched structure, the Central Basin Decollement [Shaw & Suppe, 1996], underlies the Los Angeles Basin. By simulating the dynamic rupture path selection, using explicit finite element methods here, we are able to estimate which faults should be activated under given conditions. Factors that influence coseismic branch activation have been extensively studied [Poliakov et al.; Kame et al.; Oglesby et al., 2003, 2004; Bhat et al., 2004, 2007]. The results show that the rupture velocity, pre-stress orientation and fault geometry influence rupture path selection. We show further that the ratio of σ1/σ3 (equivalently, the seismic S ratio) and the relative frictional fault strength also play a significant role in determining which faults are activated. Our methodology has recently included the use of a regularized friction routine [Ranjith & Rice, 2001; Cochard & Rice, 2000] which reduces the growth of numerical noise throughout the simulations. A difficulty arises in the treatment of surface interactions at the branch junction. When local opening does not occur there, slip on the branch fault must vanish at the junction, a constraint that we impose on the FE model. However, the FE contact routine used demands that slip always be constrained to zero on one or the other fault at such a junction, which is problematic when opening occurs. There is then no fundamental basis for constraining slip at the junction to zero on either fault, and the choice made affects the slip distributions and rupture path selection. Many analyses that we perform are elastic and the same material is used on both sides

  1. New branches of massive gravity

    NASA Astrophysics Data System (ADS)

    Comelli, D.; Crisostomi, M.; Koyama, K.; Pilo, L.; Tasinato, G.

    2015-06-01

    The basic building block for Lorentz-invariant and ghost-free massive gravity is the square root of the combination g-1η , where g-1 is the inverse of the physical metric and η is a reference metric. Since the square root of a matrix is not uniquely defined, it is possible to have physically inequivalent potentials corresponding to different branches. We show that around the Minkowski background, the only perturbatively well-defined branch is the potential proposed by de Rham, Gabadadze and Tolley. On the other hand, if Lorentz symmetry is broken spontaneously, other potentials exist with a standard perturbative expansion. We show this explicitly building new Lorentz-invariant, ghost-free massive gravity potentials for theories that in the background preserve rotational invariance but break Lorentz boosts.

  2. Control of carbohydrate processing: increased beta-1,6 branching in N-linked carbohydrates of Lec9 CHO mutants appears to arise from a defect in oligosaccharide-dolichol biosynthesis.

    PubMed Central

    Rosenwald, A G; Stanley, P; Krag, S S

    1989-01-01

    A correlation between increased beta-1,6 branching of N-linked carbohydrates and the ability of a cell to metastasize or to form a tumor has been observed in several experimental models. Lec9 Chinese hamster ovary (CHO) mutants exhibit a drastic reduction in tumorigenicity in nude mice, and this phenotype directly correlates with their ability to attach an increased proportion of beta-1,6-branched carbohydrates to the G glycoprotein of vesicular stomatitis virus (J. Ripka, S. Shin, and P. Stanley, Mol. Cell. Biol. 6:1268-1275, 1986). In this paper we provide evidence that cellular carbohydrates from Lec9 cells also contain an increased proportion of beta-1,6-branched carbohydrates, although they do not possess significantly increased activity of the beta-1,6 branching enzyme (GlcNAc-transferase V). Biosynthetic labeling experiments show that a substantial degree of underglycosylation occurs in Lec9 cells and that this affects several classes of glycoproteins. Lec9 cells synthesize ca. 40-fold less Glc3Man9GlcNAc2-P-P-lipid and ca. 2-fold less Man5GlcNAc2-P-P-lipid than parental cells do. In addition, Lec9 cells possess ca. fivefold less protein-bound oligosaccharide intermediates, and one major species is resistant to release by endo-beta-N-acetylglucosaminidase H (endo H). Membranes of Lec9 cells exhibit normal mannosylphosphoryldolichol synthase, glucosylphosphoryldolichol synthase, and N-acetylglucosaminylphosphate transferase activities in the presence of exogenous dolichyl phosphate. However, in the absence of exogenous dolichyl phosphate, mannosylphosphoryldolichol synthase and glucosylphosphoryldolichol synthase activities are reduced in membranes of Lec9 cells, indicating that membranes of Lec9 cells are deficient in lipid phosphate. This was confirmed by analysis of lipids labeled by [3H]mevalonate, which showed that Lec9 cells have less lipid phosphate than parental CHO cells. Mechanisms by which a defect in the synthesis of dolichol

  3. Solid State Photovoltaic Research Branch

    SciTech Connect

    Not Available

    1990-09-01

    This report summarizes the progress of the Solid State Photovoltaic Research Branch of the Solar Energy Research Institute (SERI) from October 1, 1988, through September 30,l 1989. Six technical sections of the report cover these main areas of SERIs in-house research: Semiconductor Crystal Growth, Amorphous Silicon Research, Polycrystalline Thin Films, III-V High-Efficiency Photovoltaic Cells, Solid-State Theory, and Laser Raman and Luminescence Spectroscopy. Sections have been indexed separately for inclusion on the data base.

  4. Horizontal-branch stellar evolution

    NASA Technical Reports Server (NTRS)

    Sweigart, Allen V.

    1990-01-01

    The results of canonical theory for the evolution of horizontal-branch (HB) stars are examined. Particular attention is given to how an HB star maintains the appropriate composition distribution within the semiconvective zone and how this composition is affected by the finite time-dependence with which convective boundaries actually move. Newly developed models based on time-dependent overshooting are presented for both the core-helium-exhaustion and main HB phases.

  5. Geodynamics Branch research report, 1982

    NASA Technical Reports Server (NTRS)

    Kahn, W. D. (Editor); Cohen, S. C. (Editor)

    1983-01-01

    The research program of the Geodynamics Branch is summarized. The research activities cover a broad spectrum of geoscience disciplines including space geodesy, geopotential field modeling, tectonophysics, and dynamic oceanography. The NASA programs which are supported by the work described include the Geodynamics and Ocean Programs, the Crustal Dynamics Project, the proposed Ocean Topography Experiment (TOPEX) and Geopotential Research Mission. The individual papers are grouped into chapters on Crustal Movements, Global Earth Dynamics, Gravity Field Model Development, Sea Surface Topography, and Advanced Studies.

  6. Actin filament curvature biases branching direction

    NASA Astrophysics Data System (ADS)

    Wang, Evan; Risca, Viviana; Chaudhuri, Ovijit; Chia, Jia-Jun; Geissler, Phillip; Fletcher, Daniel

    2012-02-01

    Actin filaments are key components of the cellular machinery, vital for a wide range of processes ranging from cell motility to endocytosis. Actin filaments can branch, and essential in this process is a protein complex known as the Arp2/3 complex, which nucleate new ``daughter'' filaments from pre-existing ``mother'' filaments by attaching itself to the mother filament. Though much progress has been made in understanding the Arp2/3-actin junction, some very interesting questions remain. In particular, F-actin is a dynamic polymer that undergoes a wide range of fluctuations. Prior studies of the Arp2/3-actin junction provides a very static notion of Arp2/3 binding. The question we ask is how differently does the Arp2/3 complex interact with a straight filament compared to a bent filament? In this study, we used Monte Carlo simulations of a surface-tethered worm-like chain to explore possible mechanisms underlying the experimental observation that there exists preferential branch formation by the Arp2/3 complex on the convex face of a curved filament. We show that a fluctuation gating model in which Arp2/3 binding to the actin filament is dependent upon a rare high-local-curvature shape fluctuation of the filament is consistent with the experimental data.

  7. Branching dynamics of viral information spreading

    NASA Astrophysics Data System (ADS)

    Iribarren, José Luis; Moro, Esteban

    2011-10-01

    Despite its importance for rumors or innovations propagation, peer-to-peer collaboration, social networking, or marketing, the dynamics of information spreading is not well understood. Since the diffusion depends on the heterogeneous patterns of human behavior and is driven by the participants’ decisions, its propagation dynamics shows surprising properties not explained by traditional epidemic or contagion models. Here we present a detailed analysis of our study of real viral marketing campaigns where tracking the propagation of a controlled message allowed us to analyze the structure and dynamics of a diffusion graph involving over 31 000 individuals. We found that information spreading displays a non-Markovian branching dynamics that can be modeled by a two-step Bellman-Harris branching process that generalizes the static models known in the literature and incorporates the high variability of human behavior. It explains accurately all the features of information propagation under the “tipping point” and can be used for prediction and management of viral information spreading processes.

  8. Branching dynamics of viral information spreading.

    PubMed

    Iribarren, José Luis; Moro, Esteban

    2011-10-01

    Despite its importance for rumors or innovations propagation, peer-to-peer collaboration, social networking, or marketing, the dynamics of information spreading is not well understood. Since the diffusion depends on the heterogeneous patterns of human behavior and is driven by the participants' decisions, its propagation dynamics shows surprising properties not explained by traditional epidemic or contagion models. Here we present a detailed analysis of our study of real viral marketing campaigns where tracking the propagation of a controlled message allowed us to analyze the structure and dynamics of a diffusion graph involving over 31,000 individuals. We found that information spreading displays a non-Markovian branching dynamics that can be modeled by a two-step Bellman-Harris branching process that generalizes the static models known in the literature and incorporates the high variability of human behavior. It explains accurately all the features of information propagation under the "tipping point" and can be used for prediction and management of viral information spreading processes.

  9. Biochemical characterisation of a glycogen branching enzyme from Streptococcus mutans: Enzymatic modification of starch.

    PubMed

    Kim, Eun-Joo; Ryu, Soo-In; Bae, Hyun-Ah; Huong, Nguyen Thi; Lee, Soo-Bok

    2008-10-15

    A gene encoding a putative glycogen branching enzyme (SmGBE) in Streptococcus mutans was expressed in Escherichia coli and purified. The biochemical properties of the purified enzyme were examined relative to its branching specificity for amylose and starch. The activity of the approximately 75kDa enzyme was optimal at pH 5.0, and stable up to 40°C. The enzyme predominantly transferred short maltooligosyl chains with a degree of polymerization (dp) of 6 and 7 throughout the branching process for amylose. When incubated with rice starch, the enzyme modified its optimal branch chain-length from dp 12 to 6 with large reductions in the longer chains, and simultaneously increased its branching points. The results indicate that SmGBE can make a modified starch with much shorter branches and a more branched structure than to native starch. In addition, starch retrogradation due to low temperature storage was significantly retarded along with the enzyme reaction.

  10. Soils of Walker Branch Watershed

    SciTech Connect

    Lietzke, D.A.

    1994-01-01

    The soil survey of Walker Branch Watershed (WBW) utilized the most up-to-date knowledge of soils, geology, and geohydrology in building the soils data base needed to reinterpret past research and to begin new research in the watershed. The soils of WBW were also compared with soils mapped elsewhere along Chestnut Ridge on the Oak Ridge Reservation to (1) establish whether knowledge obtained elsewhere could be used within the watershed, (2) determine whether there were any soils restricted to the watershed, and (3) evaluate geologic formation lateral variability. Soils, surficial geology, and geomorphology were mapped at a scale of 1:1200 using a paper base map having 2-ft contour intervals. Most of the contours seemed to reasonably represent actual landform configurations, except for dense wooded areas. For example, the very large dolines or sinkholes were shown on the contour base map, but numerous smaller ones were not. In addition, small drainageways and gullies were often not shown. These often small but important features were located approximately as soil mapping progressed. WBW is underlain by dolostones of the Knox Group, but only a very small part of the surface area contains outcroppings of rock and most outcrops were located in the lower part. Soil mapping revealed the presence of both ancient alluvium and ancient colluvium deposits, not recognized in previous soil surveys, that have been preserved in high-elevation stable portions of present-day landforms. An erosional geomorphic process of topographic inversion requiring several millions of years within the Pleistocene is necessary to bring about the degree of inversion that is expressed in the watershed. Indeed, some of these ancient alluvial and colluvial remnants may date back into the Tertiary. Also evident in the watershed, and preserved in the broad, nearly level bottoms of dolines, are multiple deposits of silty material either devoid or nearly devoid of coarse fragments. Recent research

  11. Strategy of Irrigation Branch in Russia

    NASA Astrophysics Data System (ADS)

    Zeyliger, A.; Ermolaeva, O.

    2012-04-01

    At this moment, at the starting time of the program on restoration of a large irrigation in Russia till 2020, the scientific and technical community of irrigation branch does not have clear vision on how to promote a development of irrigated agriculture and without repeating of mistakes having a place in the past. In many respects absence of a vision is connected to serious backlog of a scientific and technical and informational and technological level of development of domestic irrigation branch from advanced one. Namely such level of development is necessary for the resolving of new problems in new conditions of managing, and also for adequate answers to new challenges from climate and degradation of ground & water resources, as well as a rigorous requirement from an environment. In such important situation for irrigation branch when it is necessary quickly generate a scientific and technical politics for the current decade for maintenance of translation of irrigated agriculture in the Russian Federation on a new highly effective level of development, in our opinion, it is required to carry out open discussion of needs and requirements as well as a research for a adequate solutions. From political point of view a framework organized in FP6 DESIRE 037046 project is an example of good practice that can serve as methodical approach how to organize and develop such processes. From technical point of view a technology of operational management of irrigation at large scale presents a prospective alternative to the current type of management based on planning. From point of view ICT operational management demands creation of a new platform for the professional environment of activity. This platform should allow to perceive processes in real time, at their partial predictability on signals of a straight line and a feedback, within the framework of variability of decision making scenarious, at high resolution and the big ex-awning of sensor controls and the gauges

  12. Do Vascular Networks Branch Optimally or Randomly across Spatial Scales?

    PubMed

    Tekin, Elif; Hunt, David; Newberry, Mitchell G; Savage, Van M

    2016-11-01

    Modern models that derive allometric relationships between metabolic rate and body mass are based on the architectural design of the cardiovascular system and presume sibling vessels are symmetric in terms of radius, length, flow rate, and pressure. Here, we study the cardiovascular structure of the human head and torso and of a mouse lung based on three-dimensional images processed via our software Angicart. In contrast to modern allometric theories, we find systematic patterns of asymmetry in vascular branching, potentially explaining previously documented mismatches between predictions (power-law or concave curvature) and observed empirical data (convex curvature) for the allometric scaling of metabolic rate. To examine why these systematic asymmetries in vascular branching might arise, we construct a mathematical framework to derive predictions based on local, junction-level optimality principles that have been proposed to be favored in the course of natural selection and development. The two most commonly used principles are material-cost optimizations (construction materials or blood volume) and optimization of efficient flow via minimization of power loss. We show that material-cost optimization solutions match with distributions for asymmetric branching across the whole network but do not match well for individual junctions. Consequently, we also explore random branching that is constrained at scales that range from local (junction-level) to global (whole network). We find that material-cost optimizations are the strongest predictor of vascular branching in the human head and torso, whereas locally or intermediately constrained random branching is comparable to material-cost optimizations for the mouse lung. These differences could be attributable to developmentally-programmed local branching for larger vessels and constrained random branching for smaller vessels.

  13. Do Vascular Networks Branch Optimally or Randomly across Spatial Scales?

    PubMed Central

    Newberry, Mitchell G.; Savage, Van M.

    2016-01-01

    Modern models that derive allometric relationships between metabolic rate and body mass are based on the architectural design of the cardiovascular system and presume sibling vessels are symmetric in terms of radius, length, flow rate, and pressure. Here, we study the cardiovascular structure of the human head and torso and of a mouse lung based on three-dimensional images processed via our software Angicart. In contrast to modern allometric theories, we find systematic patterns of asymmetry in vascular branching, potentially explaining previously documented mismatches between predictions (power-law or concave curvature) and observed empirical data (convex curvature) for the allometric scaling of metabolic rate. To examine why these systematic asymmetries in vascular branching might arise, we construct a mathematical framework to derive predictions based on local, junction-level optimality principles that have been proposed to be favored in the course of natural selection and development. The two most commonly used principles are material-cost optimizations (construction materials or blood volume) and optimization of efficient flow via minimization of power loss. We show that material-cost optimization solutions match with distributions for asymmetric branching across the whole network but do not match well for individual junctions. Consequently, we also explore random branching that is constrained at scales that range from local (junction-level) to global (whole network). We find that material-cost optimizations are the strongest predictor of vascular branching in the human head and torso, whereas locally or intermediately constrained random branching is comparable to material-cost optimizations for the mouse lung. These differences could be attributable to developmentally-programmed local branching for larger vessels and constrained random branching for smaller vessels. PMID:27902691

  14. Bird exclosures for branches and whole trees.

    Treesearch

    Robert W. Campbell; Torolf R. Torgersen; Steven C. Forrest; Lorna C. Youngs

    1981-01-01

    Two types of lightweight, portable bird exclosures are described. One is for individual branches or branch tips; the other is for whole trees up to 9 m tall. Several alternative configurations and uses of these exclosures are discussed.

  15. Managing occurrence branching in qualitative simulation

    SciTech Connect

    Tokuda, L.

    1996-12-31

    Qualitative simulators can produce common sense abstractions of complex behaviors given only partial knowledge about a system. One of the problems which limits the applicability of qualitative simulators is the intractable branching of successor states encountered with model of even modest size. Some branches may be unavoidable due to the complex nature of a system. Other branches may be accidental results of the model chosen. A common source of intractability is occurrence branching. Occurrence branching occurs when the state transitions of two variables are unordered with respect to each other. This paper extends the QSIM model to distinguish between interesting occurrence branching and uninteresting occurrence branching. A representation, algorithm, and simulator for efficiently handling uninteresting branching is presented.

  16. Branching N-linked oligosaccharides in breast cancer.

    PubMed

    Korczak, B; Goss, P; Fernandez, B; Baker, M; Dennis, J W

    1994-01-01

    Tumor progression in rodent and human tumors is commonly associated with changes in glycoprotein glycosylation, in particular increased beta 1-6GlcNAc-branching, a regulatory step in expression of polylactosamine and extended-chain Lewis antigens. Loss of the branched oligosaccharides in murine tumor cells either due to somatic mutation, or treatment of the cells with the oligosaccharide processing inhibitor swainsonine, blocks tumor cells invasion in vitro and reduces solid tumor growth in vivo. Swainsonine and other inhibitors of N-linked oligosaccharide processing may be useful anti-cancer drugs, a premise which has begun to be tested in humans.

  17. The Effects of a Branch Campus

    ERIC Educational Resources Information Center

    Lien, Donald; Wang, Yaqin

    2012-01-01

    We examine the effects of a branch campus on the social welfare of the host country and the foreign university. Overall, we find that a branch campus increases both the domestic social welfare (measured by the aggregate student utility) and the tuition revenue of the foreign university. The effect of a branch campus on the brain drain is…

  18. Structural dynamics branch research and accomplishments

    NASA Technical Reports Server (NTRS)

    1990-01-01

    Summaries are presented of fiscal year 1989 research highlights from the Structural Dynamics Branch at NASA Lewis Research Center. Highlights from the branch's major work areas include aeroelasticity, vibration control, dynamic systems, and computation structural methods. A listing of the fiscal year 1989 branch publications is given.

  19. Introduction of Branching Degrees of Octane Isomers.

    PubMed

    Perdih, Anton

    2016-01-01

    The concept of branching degrees is introduced. In the case of octane isomers it is derived from the values of a set of their physicochemical properties, calculating for each isomer the average of the normalized values and these averages are defined as branching degrees of octane isomers. The sequence of these branching degrees of octane isomers does not differ much from the »regular« one defined earlier. 2,2-Dimethylhexane appears to be less branched than 3,4-dimethylhexane and 3-ethyl, 2-methylpentane, whereas 2,3,4-trimethylpentane appears to be less branched than 3-ethyl, 3-methylpentane. While the increasing number of branches gives rise to increasing branching degrees, the peripheral position of branches and the separation between branches decreases the value of the branching degree. The central position of branches increases it. A bigger branch increases it more than a smaller one. The quantification of these structural features and their correlations with few indices is given as well.

  20. Guide to the Seattle Archives Branch.

    ERIC Educational Resources Information Center

    Hobbs, Richard, Comp.

    The guide presents an overview of the textual and microfilmed records located at the Seattle Branch of the National Archives of the United States. Established in 1969, the Seattle Archives Branch is one of 11 branches which preserve and make available for research those U.S. Government records of permanent value created and maintained by Federal…

  1. Stability of earthquake clustering models: criticality and branching ratios.

    PubMed

    Zhuang, Jiancang; Werner, Maximilian J; Harte, David S

    2013-12-01

    We study the stability conditions of a class of branching processes prominent in the analysis and modeling of seismicity. This class includes the epidemic-type aftershock sequence (ETAS) model as a special case, but more generally comprises models in which the magnitude distribution of direct offspring depends on the magnitude of the progenitor, such as the branching aftershock sequence (BASS) model and another recently proposed branching model based on a dynamic scaling hypothesis. These stability conditions are closely related to the concepts of the criticality parameter and the branching ratio. The criticality parameter summarizes the asymptotic behavior of the population after sufficiently many generations, determined by the maximum eigenvalue of the transition equations. The branching ratio is defined by the proportion of triggered events in all the events. Based on the results for the generalized case, we show that the branching ratio of the ETAS model is identical to its criticality parameter because its magnitude density is separable from the full intensity. More generally, however, these two values differ and thus place separate conditions on model stability. As an illustration of the difference and of the importance of the stability conditions, we employ a version of the BASS model, reformulated to ensure the possibility of stationarity. In addition, we analyze the magnitude distributions of successive generations of the BASS model via analytical and numerical methods, and find that the compound density differs substantially from a Gutenberg-Richter distribution, unless the process is essentially subcritical (branching ratio less than 1) or the magnitude dependence between the parent event and the direct offspring is weak.

  2. Stability of earthquake clustering models: Criticality and branching ratios

    NASA Astrophysics Data System (ADS)

    Zhuang, Jiancang; Werner, Maximilian J.; Harte, David S.

    2013-12-01

    We study the stability conditions of a class of branching processes prominent in the analysis and modeling of seismicity. This class includes the epidemic-type aftershock sequence (ETAS) model as a special case, but more generally comprises models in which the magnitude distribution of direct offspring depends on the magnitude of the progenitor, such as the branching aftershock sequence (BASS) model and another recently proposed branching model based on a dynamic scaling hypothesis. These stability conditions are closely related to the concepts of the criticality parameter and the branching ratio. The criticality parameter summarizes the asymptotic behavior of the population after sufficiently many generations, determined by the maximum eigenvalue of the transition equations. The branching ratio is defined by the proportion of triggered events in all the events. Based on the results for the generalized case, we show that the branching ratio of the ETAS model is identical to its criticality parameter because its magnitude density is separable from the full intensity. More generally, however, these two values differ and thus place separate conditions on model stability. As an illustration of the difference and of the importance of the stability conditions, we employ a version of the BASS model, reformulated to ensure the possibility of stationarity. In addition, we analyze the magnitude distributions of successive generations of the BASS model via analytical and numerical methods, and find that the compound density differs substantially from a Gutenberg-Richter distribution, unless the process is essentially subcritical (branching ratio less than 1) or the magnitude dependence between the parent event and the direct offspring is weak.

  3. Functional Redundancy of Septin Homologs in Dendritic Branching

    PubMed Central

    Kaplan, Charlotte; Steinmann, Mayra; Zapiorkowska, Natalia A.; Ewers, Helge

    2017-01-01

    Septins are cytoskeletal GTPases present in nonpolar heteromeric complexes that assemble in a palindromic fashion from two to eight subunits. Mammalian septins function in several fundamental cellular processes at the membrane-cytoskeleton interface including dendritic branching in neurons. Sequence homology divides the 13 mammalian septin genes into four homology groups. Experimental findings suggest that septin function is redundant among septins from one homology group. This is best understood for the isoforms of the SEPT2 group, which form a homodimer at the center of septin complexes. In vitro, all SEPT2-group septins form recombinant hexameric complexes with two copies of SEPT6 and SEPT7. However, it remains unclear to what extent homologs septins can substitute for each other in specific cellular processes. Here, we use the experimental paradigm of dendritic branching in hippocampal rat neurons to ask, to what extent septins of the SEPT2-group are functionally redundant. Dendritic branching is significantly reduced when SEPT5 is downregulated. In neurons expressing SEPT5-shRNA, simultaneously expressed SEPT2-GFP, and SEPT4-GFP colocalize with SEPT7 at dendritic spine necks and rescue dendritic branching. In contrast, SEPT1-GFP is diffusely distributed in the cytoplasm in SEPT5 downregulated neurons and cannot rescue dendritic branching. Our findings provide a basis for the study of septin-specific functions in cells. PMID:28265560

  4. Large branched self-assembled DNA complexes

    NASA Astrophysics Data System (ADS)

    Tosch, Paul; Wälti, Christoph; Middelberg, Anton P. J.; Davies, A. Giles

    2007-04-01

    Many biological molecules have been demonstrated to self-assemble into complex structures and networks by using their very efficient and selective molecular recognition processes. The use of biological molecules as scaffolds for the construction of functional devices by self-assembling nanoscale complexes onto the scaffolds has recently attracted significant attention and many different applications in this field have emerged. In particular DNA, owing to its inherent sophisticated self-organization and molecular recognition properties, has served widely as a scaffold for various nanotechnological self-assembly applications, with metallic and semiconducting nanoparticles, proteins, macromolecular complexes, inter alia, being assembled onto designed DNA scaffolds. Such scaffolds may typically contain multiple branch-points and comprise a number of DNA molecules selfassembled into the desired configuration. Previously, several studies have used synthetic methods to produce the constituent DNA of the scaffolds, but this typically constrains the size of the complexes. For applications that require larger self-assembling DNA complexes, several tens of nanometers or more, other techniques need to be employed. In this article, we discuss a generic technique to generate large branched DNA macromolecular complexes.

  5. Decibel: The Relational Dataset Branching System

    PubMed Central

    Maddox, Michael; Goehring, David; Elmore, Aaron J.; Madden, Samuel; Parameswaran, Aditya; Deshpande, Amol

    2017-01-01

    As scientific endeavors and data analysis become increasingly collaborative, there is a need for data management systems that natively support the versioning or branching of datasets to enable concurrent analysis, cleaning, integration, manipulation, or curation of data across teams of individuals. Common practice for sharing and collaborating on datasets involves creating or storing multiple copies of the dataset, one for each stage of analysis, with no provenance information tracking the relationships between these datasets. This results not only in wasted storage, but also makes it challenging to track and integrate modifications made by different users to the same dataset. In this paper, we introduce the Relational Dataset Branching System, Decibel, a new relational storage system with built-in version control designed to address these shortcomings. We present our initial design for Decibel and provide a thorough evaluation of three versioned storage engine designs that focus on efficient query processing with minimal storage overhead. We also develop an exhaustive benchmark to enable the rigorous testing of these and future versioned storage engine designs. PMID:28149668

  6. Fertilization Affects Branching Pattern in Norway Spruce

    NASA Astrophysics Data System (ADS)

    Palmroth, S.; Stenberg, P.; Smolander, H.

    2001-12-01

    The increase in stand productivity from fertilization can be attributed to an increase in photosynthetic capacity, and a faster accumulation of leaf area index (LAI). Differences in the steady-state LAI are likely to reflect differences in PAR interception and/or conversion efficiency at shoot and leaf level. Furthermore, shoots ability to export carbohydrates to developing buds could be the mechanism responsible for light dependent branching. Within-canopy distribution of PAR and leaf area form the core in process-based models that are used to assess impacts of changes in the environment on production and resource use efficiency of forest stands. However, feedback between structure and radiation environment is not often incorporated in the models. We studied the relationships between light availability, shoot structure and branching pattern in Norway spruce (Picea abies (L.) Karst.) at a long-term fertilization experiment at Flakaliden research area in northern Sweden. Sampling of shoots was designed to cover the variation in canopy exposure within the live crown zone, where current shoots were still found. Canopy openness was used as a measure of the light availability at the shoot?s position. Our data showed that, at similar canopy openness, shoots of fertilized trees were longer and the number and total length of daughters were higher than in control trees. Fertilization increased the steady-state LAI and resulted in a deeper canopy, i.e. foliage is produced and survive at much lower light levels.

  7. S-branch CARS applicability to thermometry

    SciTech Connect

    Akihama, K.; Asai, T. )

    1990-07-20

    The pressure and temperature dependence of background-free {ital S}-branch CARS spectra of N{sub 2} are investigated in the temperature range of 300--700 K for pressures of 1--20 atm. Collisional narrowing for {ital S}-branch CARS spectra is proved to be negligible. Individual {ital S}-branch lines are clearly resolved in the entire range, enabling unequivocal determination of temperatures by their peak ratios. Advantages and disadvantages of {ital S}-branch CARS thermometry are discussed on the basis of experimental results. The dual narrowband Stokes CARS technique is also discussed as a practical method of {ital S}-branch CARS thermometry.

  8. S-branch CARS applicability to thermometry.

    PubMed

    Akihama, K; Asai, T

    1990-07-20

    The pressure and temperature dependence of background-free S-branch CARS spectra of N(2) are investigated in the temperature range of 300-700 K for pressures of 1-20 atm. Collisional narrowing for S-branch CARS spectra is proved to be negligible. Individual S-branch lines are clearly resolved in the entire range, enabling unequivocal determination of temperatures by their peak ratios. Advantages and disadvantages of S-branch CARS thermometry are discussed on the basis of experimental results. The dual narrowband Stokes CARS technique is also discussed as a practical method of S-branch CARS thermometry.

  9. Phylogenomic analysis of glycogen branching and debranching enzymatic duo

    PubMed Central

    2014-01-01

    Background Branched polymers of glucose are universally used for energy storage in cells, taking the form of glycogen in animals, fungi, Bacteria, and Archaea, and of amylopectin in plants. Some enzymes involved in glycogen and amylopectin metabolism are similarly conserved in all forms of life, but some, interestingly, are not. In this paper we focus on the phylogeny of glycogen branching and debranching enzymes, respectively involved in introducing and removing of the α(1–6) bonds in glucose polymers, bonds that provide the unique branching structure to glucose polymers. Results We performed a large-scale phylogenomic analysis of branching and debranching enzymes in over 400 completely sequenced genomes, including more than 200 from eukaryotes. We show that branching and debranching enzymes can be found in all kingdoms of life, including all major groups of eukaryotes, and thus were likely to have been present in the last universal common ancestor (LUCA) but have been lost in seemingly random fashion in numerous single-celled eukaryotes. We also show how animal branching and debranching enzymes evolved from their LUCA ancestors by acquiring additional domains. Furthermore, we show that enzymes commonly perceived as orthologous, such as human branching enzyme GBE1 and E. coli branching enzyme GlgB, are in fact related by a gene duplication and consequently paralogous. Conclusions Despite being usually associated with animal liver glycogen and plant starch, energy storage in the form of branched glucose polymers is clearly an ancient process and has probably been present in the last universal common ancestor of all present life. The evolution of the enzymes enabling this form of energy storage is more complex than previously thought and illustrates the need for explicit phylogenomic analysis in the study of even seemingly “simple” metabolic enzymes. Patterns of conservation in the evolution of the glycogen/starch branching and debranching enzymes hint at

  10. Improved Li(+) Storage through Homogeneous N-Doping within Highly Branched Tubular Graphitic Foam.

    PubMed

    Dong, Jinyang; Xue, Yanming; Zhang, Chao; Weng, Qunhong; Dai, Pengcheng; Yang, Yijun; Zhou, Min; Li, Cuiling; Cui, Qiuhong; Kang, Xiaohong; Tang, Chengchun; Bando, Yoshio; Golberg, Dmitri; Wang, Xi

    2017-02-01

    A novel carbon structure, highly branched homogeneous-N-doped graphitic (BNG) tubular foam, is designed via a novel N, N-dimethylformamide (DMF)-mediated chemical vapor deposition method. More structural defects are found at the branched portions as compared with the flat tube domains providing abundant active sites and spacious reservoirs for Li(+) storage. An individual BNG branch nanobattery is constructed and tested using in situ transmission electron microscopy and the lithiation process is directly visualized in real time.

  11. Branched-Chain Amino Acids.

    PubMed

    Yamamoto, Keisuke; Tsuchisaka, Atsunari; Yukawa, Hideaki

    Branched-chain amino acids (BCAAs), viz., L-isoleucine, L-leucine, and L-valine, are essential amino acids that cannot be synthesized in higher organisms and are important nutrition for humans as well as livestock. They are also valued as synthetic intermediates for pharmaceuticals. Therefore, the demand for BCAAs in the feed and pharmaceutical industries is increasing continuously. Traditional industrial fermentative production of BCAAs was performed using microorganisms isolated by random mutagenesis. A collection of these classical strains was also scientifically useful to clarify the details of the BCAA biosynthetic pathways, which are tightly regulated by feedback inhibition and transcriptional attenuation. Based on this understanding of the metabolism of BCAAs, it is now possible for us to pursue strains with higher BCAA productivity using rational design and advanced molecular biology techniques. Additionally, systems biology approaches using augmented omics information help us to optimize carbon flux toward BCAA production. Here, we describe the biosynthetic pathways of BCAAs and their regulation and then overview the microorganisms developed for BCAA production. Other chemicals, including isobutanol, i.e., a second-generation biofuel, can be synthesized by branching the BCAA biosynthetic pathways, which are also outlined.

  12. Chiral methyl-branched pheromones.

    PubMed

    Ando, Tetsu; Yamakawa, Rei

    2015-07-01

    Insect pheromones are some of the most interesting natural products because they are utilized for interspecific communication between various insects, such as beetles, moths, ants, and cockroaches. A large number of compounds of many kinds have been identified as pheromone components, reflecting the diversity of insect species. While this review deals only with chiral methyl-branched pheromones, the chemical structures of more than one hundred non-terpene compounds have been determined by applying excellent analytical techniques. Furthermore, their stereoselective syntheses have been achieved by employing trustworthy chiral sources and ingenious enantioselective reactions. The information has been reviewed here not only to make them available for new research but also to understand the characteristic chemical structures of the chiral pheromones. Since biosynthetic studies are still limited, it might be meaningful to examine whether the structures, particularly the positions and configurations of the branched methyl groups, are correlated with the taxonomy of the pheromone producers and also with the function of the pheromones in communication systems.

  13. Nucleosynthesis in asymptotic giant branch stars

    SciTech Connect

    El Eid, Mounib F.

    2014-05-09

    The nucleosynthesis in asymptotic giant branch stars (briefly: AGB)is a challenging and fascinating subject in the theory of stellar evolution and important for observations as well. This is because about of half the heavy elements beyond iron are synthesized during thermal pulsation phases of these stars. Furthermore, the understanding of the production of the heavy elements and some light elements like carbon and fluorine represent a powerful tool to get more insight into the internal structure of these stars. The diversity of nuclear processing during the AGB phases may also motivate experimental activities in measuring important nuclear reactions. In this contribution, we emphasize several interesting feature of the nucleosynthesis in AGB stars which still needs further elaboration especially from theoretical point of view.

  14. Decay branching ratios of excited 24Mg

    NASA Astrophysics Data System (ADS)

    Munson, J. M.; Norman, E. B.; Burke, J. T.; Casperson, R. J.; Phair, L. W.; McCleskey, E.; McCleskey, M.; Lee, D.; Hughes, R. O.; Ota, S.; Czeszumska, A.; Chodash, P. A.; Saastamoinen, A. J.; Austin, R. A. E.; Spiridon, A. E.; Dag, M.; Chyzh, R.; Basunia, M. S.; Ressler, J. J.; Ross, T. J.

    2017-01-01

    The nuclear reactions 12C(12C,α )20Ne , 12C(12C,p )23Na , and 12C(12C,n )23Mg are the primary reactions in carbon burning, which occurs as part of several stellar processes. The Gamow window, which describes the energy range where most of these reactions take place, is typically around 1.5 MeV in the center-of-mass frame. Direct measurements of the cross sections at this energy are difficult due to the large Coulomb barrier present between the carbon nuclei; however, a successful surrogate measurement can provide the branching ratios between these reactions while avoiding the 12C+12C Coulomb barrier. An experiment was performed using inelastic scattering of 40 MeV α particles on 24Mg as a possible surrogate for the 12C+12C compound nucleus.

  15. Hyper-branched Structures via Flow Coating

    NASA Astrophysics Data System (ADS)

    Liu, Yujie; Lee, Dong; Monteux, Cécile; Crosby, Alfred

    2013-03-01

    Evaporative self-assembly has been shown to be a scalable method for organizing non-volatile solutes, e.g. nanoparticles; however, the influence of substrate surface energy in this technique has not been studied extensively. In this work, we utilize an evaporative self-assembly process based upon flexible blade flow coating to fabricate organized structures on substrates that have been modified to systematically vary surface energy. We focus on the patterning of polystyrene. We observe a variety of polystyrene structures including dots, hyper-branched patterns, stripes and lines that can be deposited on substrates with a range of wetting properties. We explain the mechanism for these structural formations based on the competition between Marangoni flow, adsorption, friction and viscosity. The development of this fundamental knowledge is important for controlling hierarchical manufacturing of nanoscale objects with different surface chemistries and compositions.

  16. Nucleosynthesis in asymptotic giant branch stars

    NASA Astrophysics Data System (ADS)

    El Eid, Mounib F.

    2014-05-01

    The nucleosynthesis in asymptotic giant branch stars (briefly: AGB)is a challenging and fascinating subject in the theory of stellar evolution and important for observations as well. This is because about of half the heavy elements beyond iron are synthesized during thermal pulsation phases of these stars. Furthermore, the understanding of the production of the heavy elements and some light elements like carbon and fluorine represent a powerful tool to get more insight into the internal structure of these stars. The diversity of nuclear processing during the AGB phases may also motivate experimental activities in measuring important nuclear reactions. In this contribution, we emphasize several interesting feature of the nucleosynthesis in AGB stars which still needs further elaboration especially from theoretical point of view.

  17. Synapse-dependent and independent mechanisms of thalamocortical axon branching are regulated by neuronal activity.

    PubMed

    Matsumoto, Naoyuki; Hoshiko, Maki; Sugo, Noriyuki; Fukazawa, Yugo; Yamamoto, Nobuhiko

    2016-03-01

    Axon branching and synapse formation are critical processes for establishing precise circuit connectivity. These processes are tightly regulated by neural activity, but the relationship between them remains largely unclear. We use organotypic coculture preparations to examine the role of synapse formation in the activity-dependent axon branching of thalamocortical (TC) projections. To visualize TC axons and their presynaptic sites, two plasmids encoding DsRed and EGFP-tagged synaptophysin (SYP-EGFP) were cotransfected into a small number of thalamic neurons. Time-lapse imaging of individual TC axons showed that most branches emerged from SYP-EGFP puncta, indicating that synapse formation precedes emergences of axonal branches. We also investigated the effects of neuronal activity on axon branching and synapse formation by manipulating spontaneous firing activity of thalamic cells. An inward rectifying potassium channel, Kir2.1, and a bacterial voltage-gated sodium channel, NaChBac, were used to suppress and promote firing activity, respectively. We found suppressing neural activity reduced both axon branching and synapse formation. In contrast, increasing neural activity promoted only axonal branch formation. Time-lapse imaging of NaChBac-expressing cells further revealed that new branches frequently appeared from the locations other than SYP-EGFP puncta, indicating that enhancing activity promotes axonal branch formation due to an increase of branch emergence at nonsynaptic sites. These results suggest that presynaptic locations are hotspots for branch emergence, and that frequent firing activity can shift branch emergence to a synapse-independent process. © 2015 Wiley Periodicals, Inc.

  18. Branching pattern of gluco-oligosaccharides and 1.5kDa dextran grafted by the α-1,2 branching sucrase GBD-CD2.

    PubMed

    Brison, Yoann; Laguerre, Sandrine; Lefoulon, François; Morel, Sandrine; Monties, Nelly; Potocki-Véronèse, Gabrielle; Monsan, Pierre; Remaud-Simeon, Magali

    2013-04-15

    GBD-CD2, an engineered sucrose-acting enzyme of glycoside hydrolase family 70, transfers D-glucopyranosyl (D-Glcp) units from sucrose onto dextrans or gluco-oligosaccharides (GOS) through the formation of α-(1→2) linkages leading to branched products of interest for health, food and cosmetic applications. Structural characterization of the branched products obtained from sucrose and pure GOS of degree of polymerization (DP) 4 or DP 5 revealed that highly α-(1→2) branched and new molecular structures can be synthesized by GBD-CD2. The formation of α-(1→2) branching is kinetically controlled and can occur onto vicinal α-(1→6)-linked D-Glcp residues. To investigate the mode of branching of 1.5 kDa dextran, simulations of various branching scenarios and resistance to glucoamylase degradation were performed. Analysis of the simulation results suggests that the branching process is stochastic and indicates that the enzyme acceptor site can accommodate both linear and poly-branched acceptors. This opens the way to the design of novel enzyme-based processes yielding carbohydrate structures varying in size and resistance to hydrolytic enzymes.

  19. Two intensified fluorescence colors' switching achieved by branched dye nanoaggregates.

    PubMed

    Ding, Ge; Lu, Yao; Su, Jihong; Qin, Xiaozhuan; Luo, Ziping; Gao, Fang; Chen, Lingyun; Li, Hongru

    2017-08-10

    In this study, a variety of branched target dyes containing double internal proton transfer segments were synthesized. For comparison, some linear analogs including a single internal proton transfer part were synthesized. The corresponding reference molecules lacking proton transfer segments were also prepared. The properties and aggregation modes of these dye aggregates were investigated on the basis of scanning electron microscopy images, transmission electron microscopy images, dynamic light scattering, X-ray diffraction, UV/visible absorption spectra and fluorescence emission spectra. The results showed that molecular aggregates with the morphologies of nano-scaled rounded or cubic particles of the target branched dyes could be yielded in mixed organic solvent/H2O solution. A remarkable emission enhancement and fluorescence switching process (from bright yellow to luminous pure blue) under 365 nm lamp irradiation was observed for these target branched dye nanoaggregates. However, no aggregates of the reference branched dyes free of hydroxyl groups were formed and no obvious spectral variations were found. In contrast, all the studied linear dyes yielded molecular nanoaggregates in mixed organic solvent/H2O solution, and only intensified single normal blue fluorescence emission was presented. This study provided real examples of some branched organic dye aggregates which were capable of displaying naked-eye enhanced fluorescence color switching under an UV lamp.

  20. Three recognition events at the branch-site adenine.

    PubMed Central

    Query, C C; Strobel, S A; Sharp, P A

    1996-01-01

    An adenosine at the branch site, the nucleophile for the first transesterification step of splicing, is nearly invariant in mammalian pre-mRNA introns. The chemical groups on the adenine base were varied systematically and assayed for formation of early spliceosome complexes and execution of the first and second steps of splicing. Recognition of constituents of the adenine is critical in formation of a U2 snRNP-containing complex on a minimal branch-site oligonucleotide. Furthermore, the efficiencies of the first and second chemical steps have different dependencies on the functional groups of the adenine. In total, the chemical groups on the adenine base at the branch site are differentially recognized during at least three different processes in the splicing of pre-mRNA. Moreover, a protein, p14, interacts with the adenine in a base-specific fashion and may mediate early recognition of this base. Images PMID:8635472

  1. Recursive Branching Simulated Annealing Algorithm

    NASA Technical Reports Server (NTRS)

    Bolcar, Matthew; Smith, J. Scott; Aronstein, David

    2012-01-01

    This innovation is a variation of a simulated-annealing optimization algorithm that uses a recursive-branching structure to parallelize the search of a parameter space for the globally optimal solution to an objective. The algorithm has been demonstrated to be more effective at searching a parameter space than traditional simulated-annealing methods for a particular problem of interest, and it can readily be applied to a wide variety of optimization problems, including those with a parameter space having both discrete-value parameters (combinatorial) and continuous-variable parameters. It can take the place of a conventional simulated- annealing, Monte-Carlo, or random- walk algorithm. In a conventional simulated-annealing (SA) algorithm, a starting configuration is randomly selected within the parameter space. The algorithm randomly selects another configuration from the parameter space and evaluates the objective function for that configuration. If the objective function value is better than the previous value, the new configuration is adopted as the new point of interest in the parameter space. If the objective function value is worse than the previous value, the new configuration may be adopted, with a probability determined by a temperature parameter, used in analogy to annealing in metals. As the optimization continues, the region of the parameter space from which new configurations can be selected shrinks, and in conjunction with lowering the annealing temperature (and thus lowering the probability for adopting configurations in parameter space with worse objective functions), the algorithm can converge on the globally optimal configuration. The Recursive Branching Simulated Annealing (RBSA) algorithm shares some features with the SA algorithm, notably including the basic principles that a starting configuration is randomly selected from within the parameter space, the algorithm tests other configurations with the goal of finding the globally optimal

  2. Multiparameter Parallel Search Branch Switching

    NASA Astrophysics Data System (ADS)

    Henderson, Michael E.

    A continuation method (sometimes called path following) is a way to compute solution curves of a nonlinear system of equations with a parameter. We derive a simple algorithm for branch switching at bifurcation points for multiple parameter continuation, where surfaces bifurcate along singular curves on a surface. It is a generalization of the parallel search technique used in the continuation code AUTO, and avoids the need for second derivatives and a full analysis of the bifurcation point. The one parameter case is special. While the generalization is not difficult, it is nontrivial, and the geometric interpretation may be of some interest. An additional tangent calculation at a point near the singular point is used to estimate the tangent to the singular set.

  3. Vere-Jones' self-similar branching model.

    PubMed

    Saichev, A; Sornette, D

    2005-11-01

    Motivated by its potential application to earthquake statistics as well as for its intrinsic interest in the theory of branching processes, we study the exactly self-similar branching process introduced recently by Vere-Jones. This model extends the ETAS class of conditional self-excited branching point-processes of triggered seismicity by removing the problematic need for a minimum (as well as maximum) earthquake size. To make the theory convergent without the need for the usual ultraviolet and infrared cutoffs, the distribution of magnitudes m' of daughters of first-generation of a mother of magnitude m has two branches m < m' with exponent beta - d and m' > m with exponent beta + d, where beta and d are two positive parameters. We investigate the condition and nature of the subcritical, critical, and supercritical regime in this and in an extended version interpolating smoothly between several models. We predict that the distribution of magnitudes of events triggered by a mother of magnitude m over all generations has also two branches m' < m with exponent and with exponent beta - h, with h=d squareroot of (1-s), where s is the fraction of triggered events. This corresponds to a renormalization of the exponent d into h by the hierarchy of successive generations of triggered events. For a significant part of the parameter space, the distribution of magnitudes over a full catalog summed over an average steady flow of spontaneous sources (immigrants) reproduces the distribution of the spontaneous sources with a single branch and is blind to the exponents beta, d of the distribution of triggered events. Since the distribution of earthquake magnitudes is usually obtained with catalogs including many sequences, we conclude that the two branches of the distribution of aftershocks are not directly observable and the model is compatible with real seismic catalogs. In summary, the exactly self-similar Vere-Jones model provides an attractive new approach to model triggered

  4. Vere-Jones' self-similar branching model

    NASA Astrophysics Data System (ADS)

    Saichev, A.; Sornette, D.

    2005-11-01

    Motivated by its potential application to earthquake statistics as well as for its intrinsic interest in the theory of branching processes, we study the exactly self-similar branching process introduced recently by Vere-Jones. This model extends the ETAS class of conditional self-excited branching point-processes of triggered seismicity by removing the problematic need for a minimum (as well as maximum) earthquake size. To make the theory convergent without the need for the usual ultraviolet and infrared cutoffs, the distribution of magnitudes m' of daughters of first-generation of a mother of magnitude m has two branches m'm with exponent β+d , where β and d are two positive parameters. We investigate the condition and nature of the subcritical, critical, and supercritical regime in this and in an extended version interpolating smoothly between several models. We predict that the distribution of magnitudes of events triggered by a mother of magnitude m over all generations has also two branches m'm with exponent β+h , with h=d1-s , where s is the fraction of triggered events. This corresponds to a renormalization of the exponent d into h by the hierarchy of successive generations of triggered events. For a significant part of the parameter space, the distribution of magnitudes over a full catalog summed over an average steady flow of spontaneous sources (immigrants) reproduces the distribution of the spontaneous sources with a single branch and is blind to the exponents β,d of the distribution of triggered events. Since the distribution of earthquake magnitudes is usually obtained with catalogs including many sequences, we conclude that the two branches of the distribution of aftershocks are not directly observable and the model is compatible with real seismic catalogs. In summary, the exactly self-similar Vere-Jones model provides an attractive new approach to model triggered seismicity, which

  5. Vere-Jones' self-similar branching model

    SciTech Connect

    Saichev, A.; Sornette, D.

    2005-11-01

    Motivated by its potential application to earthquake statistics as well as for its intrinsic interest in the theory of branching processes, we study the exactly self-similar branching process introduced recently by Vere-Jones. This model extends the ETAS class of conditional self-excited branching point-processes of triggered seismicity by removing the problematic need for a minimum (as well as maximum) earthquake size. To make the theory convergent without the need for the usual ultraviolet and infrared cutoffs, the distribution of magnitudes m{sup '} of daughters of first-generation of a mother of magnitude m has two branches m{sup '}m with exponent {beta}+d, where {beta} and d are two positive parameters. We investigate the condition and nature of the subcritical, critical, and supercritical regime in this and in an extended version interpolating smoothly between several models. We predict that the distribution of magnitudes of events triggered by a mother of magnitude m over all generations has also two branches m{sup '}m with exponent {beta}+h, with h=d{radical}(1-s), where s is the fraction of triggered events. This corresponds to a renormalization of the exponent d into h by the hierarchy of successive generations of triggered events. For a significant part of the parameter space, the distribution of magnitudes over a full catalog summed over an average steady flow of spontaneous sources (immigrants) reproduces the distribution of the spontaneous sources with a single branch and is blind to the exponents {beta},d of the distribution of triggered events. Since the distribution of earthquake magnitudes is usually obtained with catalogs including many sequences, we conclude that the two branches of the distribution of aftershocks are not directly observable and the model is compatible with real seismic catalogs. In summary, the exactly self-similar Vere-Jones model provides an

  6. Interactive Design and Visualization of Branched Covering Spaces.

    PubMed

    Roy, Lawrence; Kumar, Prashant; Golbabaei, Sanaz; Zhang, Yue; Zhang, Eugene

    2017-08-29

    Branched covering spaces are a mathematical concept which originates from complex analysis and topology and has applications in tensor field topology and geometry remeshing. Given a manifold surface and an N-way rotational symmetry field, a branched covering space is a manifold surface that has an N-to-1 map to the original surface except at the ramification points, which correspond to the singularities in the rotational symmetry field. Understanding the notion and mathematical properties of branched covering spaces is important to researchers in tensor field visualization and geometry processing, and their application areas. In this paper, we provide a framework to interactively design and visualize the branched covering space (BCS) of an input mesh surface and a rotational symmetry field defined on it. In our framework, the user can visualize not only the BCSs but also their construction process. In addition, our system allows the user to design the geometric realization of the BCS using mesh deformation techniques as well as connecting tubes. This enables the user to verify important facts about BCSs such as that they are manifold surfaces around singularities, as well as the Riemann-Hurwitz formula which relates the Euler characteristic of the BCS to that of the original mesh. Our system is evaluated by student researchers in scientific visualization and geometry processing as well as faculty members in mathematics at our university who teach topology. We include their evaluations and feedback in the paper.

  7. Vegetation survey of PEN Branch wetlands

    SciTech Connect

    Not Available

    1991-01-01

    A survey was conducted of vegetation along Pen Branch Creek at Savannah River Site (SRS) in support of K-Reactor restart. Plants were identified to species by overstory, understory, shrub, and groundcover strata. Abundance was also characterized and richness and diversity calculated. Based on woody species basal area, the Pen Branch delta was the most impacted, followed by the sections between the reactor and the delta. Species richness for shrub and groundcover strata were also lowest in the delta. No endangered plant species were found. Three upland pine areas were also sampled. In support of K Reactor restart, this report summarizes a study of the wetland vegetation along Pen Branch. Reactor effluent enters Indian Grove Branch and then flows into Pen Branch and the Pen Branch Delta.

  8. Vegetation survey of PEN Branch wetlands

    SciTech Connect

    Not Available

    1991-01-01

    A survey was conducted of vegetation along Pen Branch Creek at Savannah River Site (SRS) in support of K-Reactor restart. Plants were identified to species by overstory, understory, shrub, and groundcover strata. Abundance was also characterized and richness and diversity calculated. Based on woody species basal area, the Pen Branch delta was the most impacted, followed by the sections between the reactor and the delta. Species richness for shrub and groundcover strata were also lowest in the delta. No endangered plant species were found. Three upland pine areas were also sampled. In support of K Reactor restart, this report summarizes a study of the wetland vegetation along Pen Branch. Reactor effluent enters Indian Grove Branch and then flows into Pen Branch and the Pen Branch Delta.

  9. Research program of the Geodynamics Branch

    NASA Technical Reports Server (NTRS)

    Kahn, W. D. (Editor); Cohen, S. C. (Editor); Boccucci, B. S. (Editor)

    1986-01-01

    This report is the Fourth Annual Summary of the Research Program of the Geodynamics Branch. The branch is located within the Laboratory for Terrestrial Physics of the Space and Earth Sciences Directorate of the Goddard Space Flight Center. The research activities of the branch staff cover a broad spectrum of geoscience disciplines including: tectonophysics, space geodesy, geopotential field modeling, and dynamic oceanography. The NASA programs which are supported by the work described in this document include the Geodynamics and Ocean Programs, the Crustal Dynamics Project and the proposed Ocean Topography Experiment (TOPEX). The reports highlight the investigations conducted by the Geodynamics Branch staff during calendar year 1985. The individual papers are grouped into chapters on Crustal Movements and Solid Earth Dynamics, Gravity Field Modeling and Sensing Techniques, and Sea Surface Topography. Further information on the activities of the branch or the particular research efforts described herein can be obtained through the branch office or from individual staff members.

  10. Branched chain amino acid metabolism in the biosynthesis of Lycopersicon pennellii glucose esters

    SciTech Connect

    Walters, D.S.; Steffens, J.C. )

    1990-08-01

    Lycopersicon pennellii Corr. (D'Arcy) an insect-resistant, wild tomato possesses high densities of glandular trichomes which exude a mixture of 2,3,4-tri-O-acylated glucose esters that function as a physical impediment and feeding deterrent to small arthropod pests. The acyl moieties are branched C{sub 4} and C{sub 5} acids, and branched and straight chain C{sub 10}, C{sub 11}, and C{sub 12} acids. The structure of the branched acyl constituents suggests that the branched chain amino acid biosynthetic pathway participates in their biosynthesis. ({sup 14}C)Valine and deuterated branched chain amino acids (and their oxo-acid derivatives) were incorporated into branched C{sub 4} and C{sub 5} acid groups of glucose esters by a process of transamination, oxidative decarboxylation and subsequent acylation. C{sub 4} and C{sub 5} branched acids were elongated by two carbon units to produce the branched C{sub 10}-C{sub 12} groups. Norvaline, norleucine, allylglycine, and methionine also were processed into acyl moieties and secreted from the trichomes as glucose esters. Changes in the acyl composition of the glucose esters following sulfonylurea herbicide administration support the participation of acetohydroxyacid synthetase and the other enzymes of branched amino acid biosynthesis in the production of glucose esters.

  11. Quantitative Analysis of Axonal Branch Dynamics in the Developing Nervous System

    PubMed Central

    Scott, Ethan K.; Goodhill, Geoffrey J.

    2016-01-01

    Branching is an important mechanism by which axons navigate to their targets during neural development. For instance, in the developing zebrafish retinotectal system, selective branching plays a critical role during both initial pathfinding and subsequent arborisation once the target zone has been reached. Here we show how quantitative methods can help extract new information from time-lapse imaging about the nature of the underlying branch dynamics. First, we introduce Dynamic Time Warping to this domain as a method for automatically matching branches between frames, replacing the effort required for manual matching. Second, we model branch dynamics as a birth-death process, i.e. a special case of a continuous-time Markov process. This reveals that the birth rate for branches from zebrafish retinotectal axons, as they navigate across the tectum, increased over time. We observed no significant change in the death rate for branches over this time period. However, blocking neuronal activity with TTX slightly increased the death rate, without a detectable change in the birth rate. Third, we show how the extraction of these rates allows computational simulations of branch dynamics whose statistics closely match the data. Together these results reveal new aspects of the biology of retinotectal pathfinding, and introduce computational techniques which are applicable to the study of axon branching more generally. PMID:26998842

  12. Combining living anionic polymerization with branching reactions in an iterative fashion to design branched polymers.

    PubMed

    Higashihara, Tomoya; Sugiyama, Kenji; Yoo, Hee-Soo; Hayashi, Mayumi; Hirao, Akira

    2010-06-16

    This paper reviews the precise synthesis of many-armed and multi-compositional star-branched polymers, exact graft (co)polymers, and structurally well-defined dendrimer-like star-branched polymers, which are synthetically difficult, by a commonly-featured iterative methodology combining living anionic polymerization with branched reactions to design branched polymers. The methodology basically involves only two synthetic steps; (a) preparation of a polymeric building block corresponding to each branched polymer and (b) connection of the resulting building unit to another unit. The synthetic steps were repeated in a stepwise fashion several times to successively synthesize a series of well-defined target branched polymers.

  13. Mechanical Components Branch Test Facilities and Capabilities

    NASA Technical Reports Server (NTRS)

    Oswald, Fred B.

    2004-01-01

    The Mechanical Components Branch at NASA Glenn Research Center formulates, conducts, and manages research focused on propulsion systems for both present and advanced aeronautical and space vehicles. The branch is comprised of research teams that perform basic research in three areas: mechanical drives, aerospace seals, and space mechanisms. Each team has unique facilities for testing aerospace hardware and concepts. This report presents an overview of the Mechanical Components Branch test facilities.

  14. 31 CFR 100.2 - Scope of regulations; transactions effected through Federal Reserve banks and branches...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... effected through Federal Reserve banks and branches; distribution of coin and currencies. 100.2 Section 100... effected through Federal Reserve banks and branches; distribution of coin and currencies. The regulations... national bank notes and Federal Reserve bank notes in process of retirement and Federal Reserve notes...

  15. 31 CFR 100.2 - Scope of regulations; transactions effected through Federal Reserve banks and branches...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... effected through Federal Reserve banks and branches; distribution of coin and currencies. 100.2 Section 100... effected through Federal Reserve banks and branches; distribution of coin and currencies. The regulations... national bank notes and Federal Reserve bank notes in process of retirement and Federal Reserve notes...

  16. 31 CFR 100.2 - Scope of regulations; transactions effected through Federal Reserve banks and branches...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... effected through Federal Reserve banks and branches; distribution of coin and currencies. 100.2 Section 100... effected through Federal Reserve banks and branches; distribution of coin and currencies. The regulations... national bank notes and Federal Reserve bank notes in process of retirement and Federal Reserve notes...

  17. 31 CFR 100.2 - Scope of regulations; transactions effected through Federal Reserve banks and branches...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... effected through Federal Reserve banks and branches; distribution of coin and currencies. 100.2 Section 100... effected through Federal Reserve banks and branches; distribution of coin and currencies. The regulations... national bank notes and Federal Reserve bank notes in process of retirement and Federal Reserve notes...

  18. Toward improved branch prediction through data mining.

    SciTech Connect

    Hemmert, K. Scott; Johnson, D. Eric

    2009-09-01

    Data mining and machine learning techniques can be applied to computer system design to aid in optimizing design decisions, improving system runtime performance. Data mining techniques have been investigated in the context of branch prediction. Specifically, a comparison of traditional branch predictor performance has been made to data mining algorithms. Additionally, the possiblity of whether additional features available within the architectural state might serve to further improve branch prediction has been evaluated. Results show that data mining techniques indicate potential for improved branch prediction, especially when register file contents are included as a feature set.

  19. Branched silver nanowires as controllable plasmon routers.

    PubMed

    Fang, Yurui; Li, Zhipeng; Huang, Yingzhou; Zhang, Shunping; Nordlander, Peter; Halas, Naomi J; Xu, Hongxing

    2010-05-12

    Using polarization dependent scattering spectroscopy, we investigate plasmon propagation on branched silver nanowires. By controlling the polarization of the incident laser light, the wire plasmons can be routed into different wire branches and result in light emission from the corresponding wire ends. This routing behavior is found to be strongly dependent on the wavelength of light. Thus for certain incident polarizations, light of different wavelength will be routed into different branches. The branched nanowire can thus serve as a controllable router and multiplexer in integrated plasmonic circuits.

  20. Clinical and Translational Epidemiology Branch (CTEB)

    Cancer.gov

    The Clinical and Translational Epidemiology Branch focuses on factors that influence cancer progression, recurrence, survival, and other treatment outcomes, and factors associated with cancer development.

  1. Ventricular fiber optimization utilizing the branching structure.

    PubMed

    Washio, Takumi; Yoneda, Kazunori; Okada, Jun-Ichi; Kariya, Taro; Sugiura, Seiryo; Hisada, Toshiaki

    2016-07-01

    In this paper, we propose an algorithm that optimizes the ventricular fiber structure of the human heart. A number of histological studies and diffusion tensor magnetic resonance imaging analyses have revealed that the myocardial fiber forms a right-handed helix at the endocardium. However, the fiber formation changes its orientation as a function of transmural depth, becoming a left-handed helix at the epicardium. To determine how nature can construct such a structure, which obtains surprising pumping performance, we introduce macroscopic modeling of the branching structure of cardiac myocytes in our finite element ventricular model and utilize this in an optimization process. We put a set of multidirectional fibers around a central fiber orientation at each point of the ventricle walls and simulate heartbeats by generating contraction forces along each of these directions. We examine two optimization processes using the workloads or impulses measured in these directions to update the central fiber orientation. Both processes improve the pumping performance towards an optimal value within several tens of heartbeats, starting from an almost-flat fiber orientation. However, compared with the workload optimization, the impulse optimization produces better agreement with experimental studies on transmural changes of fiber helix angle, streamline patterns of characteristic helical structures, and temporal changes in strain. Furthermore, the impulse optimization is robust under geometrical changes of the heart and tends to homogenize various mechanical factors such as the stretch and stretch rate along the fiber orientation, the contraction force, and energy consumption. Copyright © 2015 John Wiley & Sons, Ltd.

  2. On an Integral with Two Branch Points

    ERIC Educational Resources Information Center

    de Oliveira, E. Capelas; Chiacchio, Ary O.

    2006-01-01

    The paper considers a class of real integrals performed by using a convenient integral in the complex plane. A complex integral containing a multi-valued function with two branch points is transformed into another integral containing a pole and a unique branch point. As a by-product we obtain a new class of integrals which can be calculated in a…

  3. Epithelial dynamics of pancreatic branching morphogenesis

    PubMed Central

    Villasenor, Alethia; Chong, Diana C.; Henkemeyer, Mark; Cleaver, Ondine

    2010-01-01

    The mammalian pancreas is a highly branched gland, essential for both digestion and glucose homeostasis. Pancreatic branching, however, is poorly understood, both at the ultrastructural and cellular levels. In this article, we characterize the morphogenesis of pancreatic branches, from gross anatomy to the dynamics of their epithelial organization. We identify trends in pancreatic branch morphology and introduce a novel mechanism for branch formation, which involves transient epithelial stratification and partial loss of cell polarity, changes in cell shape and cell rearrangements, de novo tubulogenesis and epithelial tubule remodeling. In contrast to the classical epithelial budding and tube extension observed in other organs, a pancreatic branch takes shape as a multi-lumen tubular plexus coordinately extends and remodels into a ramifying, single-lumen ductal system. Moreover, our studies identify a role for EphB signaling in epithelial remodeling during pancreatic branching. Overall, these results illustrate distinct, step-wise cellular mechanisms by which pancreatic epithelium shapes itself to create a functional branching organ. PMID:21098570

  4. Anaphora and Branching Direction in Japanese.

    ERIC Educational Resources Information Center

    O'Grady, William; And Others

    1994-01-01

    This paper constitutes a response to Lust and Mazuka's (1989) defense of the Principal Branching parameter and their critique of O'Grady, Suzuki-Wei, and Cho's (1986) experiment, which purported to show that even children learning left-branching languages exhibit a preference for forward patterns of anaphora. (Contains 16 references.) (JL)

  5. On an Integral with Two Branch Points

    ERIC Educational Resources Information Center

    de Oliveira, E. Capelas; Chiacchio, Ary O.

    2006-01-01

    The paper considers a class of real integrals performed by using a convenient integral in the complex plane. A complex integral containing a multi-valued function with two branch points is transformed into another integral containing a pole and a unique branch point. As a by-product we obtain a new class of integrals which can be calculated in a…

  6. Pacific Coastal Ecology Branch: Research Overview

    EPA Science Inventory

    The Pacific Coastal Ecology Branch, Newport, Oregon is part of the Western Ecology Division of the National Health and Environmental Effects Research Laboratory of the U.S. EPA. The Branch conducts research and provides scientific technical support to Headquarters and Regional O...

  7. Branching out Has So Much to Offer

    ERIC Educational Resources Information Center

    Murray, Joe

    2012-01-01

    In 1989 there were thirty ATM branches nationally. In January 2012 there were just twelve ATM branches with another three "proposed". How can that happen? How did it happen? Maybe the most pertinent question is: Why did it happen? There is no single answer to the last question, but perhaps it was something to do with the changes that…

  8. Polyphyly of true branching cyanobacteria (Stigonematales).

    PubMed

    Gugger, Muriel F; Hoffmann, Lucien

    2004-03-01

    Cyanobacteria with true branching are classified in Subsection V (formerly order Stigonematales) in the phylum CYANOBACTERIA: They exhibit a high degree of morphological complexity and are known from particular biotopes. Only a few stigonematalean morphotypes have been cultured, and therefore the high variability of morphotypes found in nature is under-represented in culture. Axenic cultures of Chlorogloeopsis and Fischerella sensu Rippka et al. were, to date, the only representatives of this Subsection in phylogenetic studies. The 16S rDNA sequence analysis data in this report confirm that heterocyst-forming cyanobacteria are a monophyletic group. However, unlike previous studies have suggested, these 16S rDNA data on new Stigonematales strains show that the true branching cyanobacteria are polyphyletic and can be separated into at least two major groups defined by their branching type, the first group being characterized by T-branching and the second group by Y-branching. Cyanobacteria with intercalary heterocysts and either no branching or false-branching also formed separate clusters. In consequence, our phylogenetic data do not correlate with the bacteriological and traditional classifications, which distinguish filamentous heterocystous cyanobacteria with or without true branching (Nostocales/Stigonematales).

  9. Phytochrome regulation of branching in Arabidopsis.

    PubMed

    Finlayson, Scott A; Krishnareddy, Srirama R; Kebrom, Tesfamichael H; Casal, Jorge J

    2010-04-01

    The red light:far-red light ratio perceived by phytochromes controls plastic traits of plant architecture, including branching. Despite the significance of branching for plant fitness and productivity, there is little quantitative and mechanistic information concerning phytochrome control of branching responses in Arabidopsis (Arabidopsis thaliana). Here, we show that in Arabidopsis, the negative effects of the phytochrome B mutation and of low red light:far-red light ratio on branching were largely due to reduced bud outgrowth capacity and an increased degree of correlative inhibition acting on the buds rather than due to a reduced number of leaves and buds available for branching. Phytochrome effects on the degree of correlative inhibition required functional BRANCHED1 (BRC1), BRC2, AXR1, MORE AXILLARY GROWTH2 (MAX2), and MAX4. The analysis of gene expression in selected buds indicated that BRC1 and BRC2 are part of different gene networks. The BRC1 network is linked to the growth capacity of specific buds, while the BRC2 network is associated with coordination of growth among branches. We conclude that the branching integrators BRC1 and BRC2 are necessary for responses to phytochrome, but they contribute differentially to these responses, likely acting through divergent pathways.

  10. Suppression of branches in Eucalyptus trees.

    PubMed

    Senthalir, P; Sharanya, S; Paramathma, M

    2004-06-01

    The effect of neem oil, which acts as a suckericide in tobacco, on branch suppression in Eucalyptus tereticornis was assessed to help maximize stem biomass. Lateral branches of selected trees were pruned, and neem oil solutions at concentrations of either 80%, 40%, 20%, 10%, or 0% (untreated control) were applied to leaf axils of the pruned branches. Regeneration of branches was suppressed, and the magnitude of suppression was proportional to the concentration of neem oil. Compared to the control, the percentage reduction in branching at 80% neem oil was 41.6%. When regenerated branches were repruned and neem oil applied at either 100%, 80%, or 0% (control), the regenerating ability of these branches was severely repressed by 78% at 100% neem oil relative to the control. Apical shoots were also topped and treated at either 100% or 0% (control) neem oil to identify the principal suppressive component in neem oil. The principal component azadirachtin was tested at 375, 750, 1500, 3125, 6250, 12 500, 25 000, 50 000, and 100 000 ppm and 0 ppm as the control. Reduction in the coppicing shoot was as high as 85%. Azadirachtin was responsible for the suppression. By pruning the lateral branches with neem oil, wasteful consumption of photosynthates can be precluded and the stem biomass maximized.

  11. Existing branches correlatively inhibit further branching in Trifolium repens: possible mechanisms

    PubMed Central

    Thomas, R. G.; Hay, M. J. M.

    2011-01-01

    In Trifolium repens removal of any number of existing branches distal to a nodal root stimulates development of axillary buds further along the stem such that the complement of branches distal to a nodal root remains constant. This study aimed to assess possible mechanisms by which existing branches correlatively inhibit the outgrowth of axillary buds distal to them. Treatments were applied to basal branches to evaluate the roles of three postulated inhibitory mechanisms: (I) the transport of a phloem-mobile inhibitory feedback signal from branches into the main stem; (II) the polar flow of auxin from branches into the main stem acting to limit further branch development; or (III) the basal branches functioning as sinks for a net root-derived stimulatory signal (NRS). Results showed that transport of auxin, or of a non-auxin phloem-mobile signal, from basal branches did not influence regulation of correlative inhibition and were consistent with the possibility that the intra-plant distribution of NRS could be involved in the correlative inhibition of distal buds by basal branches. This study supports existing evidence that regulation of branching in T. repens is dominated by a root-derived stimulatory signal, initially distributed via the xylem, the characterization of which will progress the generic understanding of branching regulation. PMID:21071681

  12. Quantitative Proteomics Analysis of Herbaceous Peony in Response to Paclobutrazol Inhibition of Lateral Branching

    PubMed Central

    Zhao, Daqiu; Gong, Saijie; Hao, Zhaojun; Meng, Jiasong; Tao, Jun

    2015-01-01

    Herbaceous peony (Paeonia lactiflora Pall.) is an emerging high-grade cut flower worldwide, which is usually used in wedding bouquets and known as the “wedding flower”. However, abundant lateral branches appear frequently in some excellent cultivars, and a lack of a method to remove Paeonia lactiflora lateral branches other than inefficient artificial methods is an obstacle for improving the quality of its cut flowers. In this study, paclobutrazol (PBZ) application was found to inhibit the growth of lateral branches in Paeonia lactiflora for the first time, including 96.82% decreased lateral bud number per branch, 77.79% and 42.31% decreased length and diameter of lateral branches, respectively, declined cell wall materials and changed microstructures. Subsequently, isobaric tag for relative and absolute quantitation (iTRAQ) technology was used for quantitative proteomics analysis of lateral branches under PBZ application and control. The results indicated that 178 differentially expressed proteins (DEPs) successfully obtained, 98 DEPs were up-regulated and 80 DEPs were down-regulated. Thereafter, 34 candidate DEPs associated with the inhibited growth of lateral branches were screened according to their function and classification. These PBZ-stress responsive candidate DEPs were involved in eight biological processes, which played a very important role in the growth and development of lateral branches together with the response to PBZ stress. These results provide a better understanding of the molecular theoretical basis for removing Paeonia lactiflora lateral branches using PBZ application. PMID:26473855

  13. Command and Data Handling Branch Internship

    NASA Technical Reports Server (NTRS)

    Billings, Rachel Mae

    2016-01-01

    Modular Integrated Stackable Layers (MISL) is a computer system designed for simple, fast, and cost effective flexible reconfiguration in space environments such as the ISS and Orion projects for various uses. Existing applications include wireless and wired communications, data acquisition and instrumentation, and camera systems, and potential applications include bus protocol converters and subsystem control. MISL is based on Texas Instruments (TI)' MSP430 16-bit ultra-low-power microcontroller device. The purpose of my project was to integrate the MISL system with a liquid crystal display (LCD) touchscreen. The LCD, manufactured by Crystalfontz and part number CFAF320240F-035T-TS, is a 320 by 240 RGB resistive color screen including an optional carrier board. The vast majority of the project was done with Altium Designer, a tool for printed circuit board (PCB) schematic capture, 3D design, and FPGA (Field Programmable Gate Array) development. The new PCB was to allow the LCD to directly stack to the rest of MISL. Research was done with datasheets for the TI microcontroller and touchscreen display in order to meet desired hardware specifications. Documentation on prior MISL projects was also utilized. The initial step was to create a schematic for the LCD, power bus, and data bus connections between components. A layout was then designed with the required physical dimensions, routed traces and vias, power and ground planes, layer stacks, and other specified design rules such as plane clearance and hole size. Multiple consultation sessions were held with Hester Yim, the technical discipline lead for the Command and Data Handling Branch, and Christy Herring, the lead PCB layout designer in the Electronic Design and Manufacturing Branch in order to ensure proper configuration. At the moment, the PCB is awaiting revision by the latter-mentioned branch. Afterwards, the board will begin to undergo the manufacturing and testing process. Throughout the internship at

  14. Source, settling and degradation of branched glycerol dialkyl glycerol tetraethers in the marine water column

    NASA Astrophysics Data System (ADS)

    Yamamoto, Masanobu; Shimamoto, Akifumi; Fukuhara, Tatsuo; Tanaka, Yuichiro

    2016-10-01

    Branched glycerol dialkyl glycerol tetraethers (branched GDGTs) are commonly found in distal marine sediments. However, their presence in the water column, source and delivery process are not fully understood. In this study, we examined seasonal and depth variation in the flux of branched GDGTs in sinking particles and underlying sediment at 39°N, 147°E in the mid-latitude NW Pacific from November 1997 to August 1999. Branched GDGTs showed synchronous variation in their sinking flux at different depths, and the variation was similar to that of lithogenic material of eolian dust origin. Their degrees of cyclization and methylation were nearly constant and bear some resemblance to those of alkaline soils. This suggests that westerly winds transport branched GDGTs to the study site via the atmosphere from continental Asia. The sinking flux of branched GDGTs was higher in 1999 than in 1998, presumably reflecting changes in the migration path of Asian dust in response to the El Niño-Southern Oscillation. Synchronous variation in branched GDGT concentrations at different depths implies rapid vertical transport of branched GDGTs to deep water with a sinking velocity exceeding 260 m d-1. The sinking flux of the branched GDGTs decreased with increasing depth, but the rate of decrease was much smaller than those of other compounds. The preservation efficiency of branched GDGTs was 3.5-6.4% of surface inputs at the water-sediment interface, which is much higher than those of isoprenoid GDGTs (1.0-1.3%) and other compounds. The branched and isoprenoid tetraether (BIT) index values were extremely low (i.e. <0.0015) in comparison with any other studies so far. The BIT values in the surface sediment were five times higher than those in sinking particles, which is attributed to the preferential preservation of branched GDGTs in oxic environments.

  15. A TrkB/EphrinA interaction controls retinal axon branching and synaptogenesis.

    PubMed

    Marler, Katharine J M; Becker-Barroso, Elena; Martínez, Albert; Llovera, Marta; Wentzel, Corinna; Poopalasundaram, Subathra; Hindges, Robert; Soriano, Eduardo; Comella, Joan; Drescher, Uwe

    2008-11-26

    Toward understanding topographically specific branching of retinal axons in their target area, we have studied the interaction between neurotrophin receptors and members of the Eph family. TrkB and its ligand BDNF are uniformly expressed in the retina and tectum, respectively, and exert a branch-promoting activity, whereas EphAs and ephrinAs are expressed in gradients in retina and tectum and can mediate a suppression of axonal branching. We have identified a novel cis interaction between ephrinA5 and TrkB on retinal ganglion cell axons. TrkB interacts with ephrinA5 via its second cysteine-rich domain (CC2), which is necessary and sufficient for binding to ephrinA5. Their functional interaction is twofold: ephrinA5 augments BDNF-promoted retinal axon branching in the absence of its activator EphA7-Fc, whereas EphA7-Fc application abolishes branching in a local and concentration-dependent manner. The importance of TrkB in this process is shown by the fact that overexpression of an isolated TrkB-CC2 domain interfering with the ephrinA/TrkB interaction abolishes this regulatory interplay, whereas knockdown of TrkB via RNA interference diminishes the ephrinA5-evoked increase in branching. The ephrinA/Trk interaction is neurotrophin induced and specifically augments the PI-3 kinase/Akt pathway generally known to be involved in the promotion of branching. In addition, ephrinAs/TrkB modulate axon branching and also synapse formation of hippocampal neurons. Our findings uncover molecular mechanisms of how spatially restricted axon branching can be achieved by linking globally expressed branch-promoting with differentially expressed branch-suppressing activities. In addition, our data suggest that growth factors and the EphA-ephrinA system interact in a way that affects axon branching and synapse development.

  16. Processing-structure-property studies of: (I) submicron polymeric fibers produced by electrospinning and (II) films of linear low density polyethylenes as influenced by the short chain branch length in copolymers of ethylene/1-butene, ethylene/1-hexene and ethylene/1-octene synthesized by a single site metallocene catalyst

    NASA Astrophysics Data System (ADS)

    Gupta, Pankaj

    The overall theme of the research discussed in this dissertation has been to explore processing-structure-property relationships for submicron polymeric fibers produced by electrospinning (Part I) and to ascertain whether or not the length of the short chain branch has any effect on the physical properties of films of linear low-density polyethylenes (LLDPEs) (Part II). The research efforts discussed in Part I of this dissertation relate to some fundamental as well as more applied investigations involving electrospinning. These include investigating the effects of solution rheology on fiber formation and developing novel methodologies to fabricate polymeric mats comprising of high specific surface submicron fibers of more than one polymer, high chemical resistant substrates produced by in situ photo crosslinking during electrospinning, superparamagnetic flexible substrates by electrospinning a solution of an elastomeric polymer containing ferrite nanoparticles of Mn-Zn-Ni and substrates for filtration applications. Bicomponent electrospinning of poly(vinyl chloride)-polyurethane and poly(vinylidiene fluoride)-polyurethane was successfully performed. In addition, filtration properties of single and bicomponent electrospun mats of polyacrylonitrile and polystyrene were investigated. Results indicated lower aerosol penetration or higher filtration efficiencies of the filters based on submicron electrospun fibers in comparison to the conventional filter materials. In addition, Part II of this dissertation explores whether or not the length of the short chain branch affects the physical properties of blown and compression molded films of LLDPEs that were synthesized by a single site metallocene catalyst. Here, three resins based on copolymers of ethylene/1-butene, ethylene/1-hexene, and ethylene/1-octene were utilized that were very similar in terms of their molecular weight and distribution, melt rheology, density, crystallinity and short chain branching content and

  17. Floral bud damage compensation by branching and biomass allocation in genotypes of Brassica napus with different architecture and branching potential

    PubMed Central

    Pinet, Amélie; Mathieu, Amélie; Jullien, Alexandra

    2015-01-01

    Plant branching is a key process in the yield elaboration of winter oilseed rape (WOSR). It is also involved in plant tolerance to flower damage because it allows the setting of new fertile inflorescences. Here we characterize the changes in the branching and distribution of the number of pods between primary and secondary inflorescences in response to floral bud clippings. Then we investigate the impacts of the modifications in branching on the biomass allocation and its consequence on the crop productivity (harvest index). These issues were addressed on plants with contrasted architecture and branching potential, using three genotypes (Exocet, Pollen, and Gamin) grown under two levels of nitrogen fertilization. Clipping treatments of increasing intensities were applied to either inflorescences or flower buds. We were able to show that restoration of the number of pods after clipping is the main lever for the compensation. Genotypes presented different behaviors in branching and biomass allocation as a function of clipping treatments. The number of fertile ramifications increased for the high intensities of clipping. In particular, the growth of secondary ramifications carried by branches developed before clipping has been observed. The proportions of yield and of number of pods carried by these secondary axes increased and became almost equivalent to the proportion carried by primary inflorescences. In terms of biomass allocation, variations have also been evidenced in the relationship between pod dry mass on a given axis and the number of pods set, while the shoot/root ratio was not modified. The harvest index presented different responses: it decreased after flower buds clipping, while it was maintained after the clipping of the whole inflorescences. The results are discussed relative to their implications regarding the identification of interesting traits to be target in breeding programs in order to improve WOSR tolerance. PMID:25759703

  18. Analysis of Capillary Rise in Asymmetric Branch-Like Capillary

    NASA Astrophysics Data System (ADS)

    Li, Caoxiong; Shen, Yinghao; Ge, Hongkui; Yang, Zhihui; Su, Shuai; Ren, Kai; Huang, Heyu

    2016-05-01

    Transport in porous media is common in nature, attracting many attentions for a long time. Tree-like network model is often used as a simplification for porous space, expressing the complexity of pore spaces instead of capillary bundle. To investigate spontaneous imbibition characteristics in this network, a dynamic asymmetric branch-like capillary model is used to represent basic network structure, using fractal method to represent tortuosity. This work investigates the influence of parameters on imbibition process in the branch-like capillary model. An analytical equation for the imbibition mass versus time is derived. Parameters from capillary structures to liquid properties are taken into account and analyzed based on the numerical solution of the equation. It is found that the imbibition process in asymmetric branch-like capillary model can be recognized by four sections and brunching tubes are positive for imbibition process. Concomitantly, meniscus arrest event is simulated and discussed. Moreover, the influence of parameters on imbibition process is discussed. These parameters can be classified as static and dynamic. Static parameters mainly change the capillary force, which are related to the ultimate imbibition mass or imbibition ability, while dynamic parameters mainly have influence on resistance of flowing fluid, which are related to the imbibition speed in the imbibition process.

  19. Using branching simulations in treatment fidelity plans.

    PubMed

    Kovach, Christine R; Rababa, Mohammad

    2014-01-01

    The purpose of this article is to present a new approach to treatment fidelity using branching simulations. Branching simulations are case scenarios that require the user to generate a series of step-by-step decisions and actions. The user is given immediate feedback on the consequences of his or her decisions and actions. Branching simulations may be a particularly useful fidelity strategy for interventions that require clinical decision making represented in terms of a flow of critical thinking and action steps. Results of fidelity testing in the current study using branching simulations revealed that 15 (22%) of 67 interventionists scored below the study's a priori 80% criterion for full retraining and retesting. Thirty (45%) interventionists needed partial retraining in using specific components of the intervention. Potential threats to internal validity posed by inadequate or erroneous adherence to multicomponent intervention protocols can be decreased through treatment fidelity using branching simulations.

  20. Toward an understanding of fibrin branching structure

    NASA Astrophysics Data System (ADS)

    Fogelson, Aaron L.; Keener, James P.

    2010-05-01

    The blood clotting enzyme thrombin converts fibrinogen molecules into fibrin monomers which polymerize to form a fibrous three-dimensional gel. The concentration of thrombin affects the architecture of the resulting gel, in particular, a higher concentration of thrombin produces a gel with more branch points per unit volume and with shorter fiber segments between branch points. We propose a mechanism by which fibrin branching can occur and show that this mechanism can lead to dependence of the gel’s structure (at the time of gelation) on the rate at which monomer is supplied. A higher rate of monomer supply leads to a gel with a higher branch concentration and with shorter fiber segments between branch points. The origin of this dependence is explained.

  1. [Croatian Medical Association--Branch Istria].

    PubMed

    Labinac-Peteh, Loredana

    2014-01-01

    Istrian branch of Croatian Medical Association was established at the Assembly in 1948. at the General Hospital Pula. From the beginning, the seat of the branch is located in Pula. During the last time the work of branch went through different periods, but has never stopped its activity, leading to the basic postulates of professionality in addition with promotion of collegiality. Istrian branch od Croatian Medical Association now has 630 members, most of members are doctors of medicine, slightly less doctors of dental medicine. At the local level Istrian branch today is recognized as expert entity for the helth and as adviser is involved in work of Department of Health in the Istrian County.

  2. Root branching: mechanisms, robustness, and plasticity.

    PubMed

    Dastidar, Mouli Ghosh; Jouannet, Virginie; Maizel, Alexis

    2012-01-01

    Plants are sessile organisms that must efficiently exploit their habitat for water and nutrients. The degree of root branching impacts the efficiency of water uptake, acquisition of nutrients, and anchorage. The root system of plants is a dynamic structure whose architecture is determined by modulation of primary root growth and root branching. This plasticity relies on the continuous integration of environmental inputs and endogenous developmental programs controlling root branching. This review focuses on the cellular and molecular mechanisms involved in the regulation of lateral root distribution, initiation, and organogenesis with the main focus on the root system of Arabidopsis thaliana. We also examine the mechanisms linking environmental changes to the developmental pathways controlling root branching. Recent progress that emphasizes the parallels to the formation of root branches in other species is discussed.

  3. Toward an understanding of fibrin branching structure.

    PubMed

    Fogelson, Aaron L; Keener, James P

    2010-05-01

    The blood clotting enzyme thrombin converts fibrinogen molecules into fibrin monomers which polymerize to form a fibrous three-dimensional gel. The concentration of thrombin affects the architecture of the resulting gel, in particular, a higher concentration of thrombin produces a gel with more branch points per unit volume and with shorter fiber segments between branch points. We propose a mechanism by which fibrin branching can occur and show that this mechanism can lead to dependence of the gel's structure (at the time of gelation) on the rate at which monomer is supplied. A higher rate of monomer supply leads to a gel with a higher branch concentration and with shorter fiber segments between branch points. The origin of this dependence is explained.

  4. Specialization and evolutionary branching within migratory populations

    PubMed Central

    Torney, Colin J.; Levin, Simon A.; Couzin, Iain D.

    2010-01-01

    Understanding the mechanisms that drive specialization and speciation within initially homogeneous populations is a fundamental challenge for evolutionary theory. It is an issue of relevance for significant open questions in biology concerning the generation and maintenance of biodiversity, the origins of reciprocal cooperation, and the efficient division of labor in social or colonial organisms. Several mathematical frameworks have been developed to address this question and models based on evolutionary game theory or the adaptive dynamics of phenotypic mutation have demonstrated the emergence of polymorphic, specialized populations. Here we focus on a ubiquitous biological phenomenon, migration. Individuals in our model may evolve the capacity to detect and follow an environmental cue that indicates a preferred migration route. The strategy space is defined by the level of investment in acquiring personal information about this route or the alternative tendency to follow the direction choice of others. The result is a relation between the migratory process and a game theoretic dynamic that is generally applicable to situations where information may be considered a public good. Through the use of an approximation of social interactions, we demonstrate the emergence of a stable, polymorphic population consisting of an uninformed subpopulation that is dependent upon a specialized group of leaders. The branching process is classified using the techniques of adaptive dynamics. PMID:21059935

  5. Specialization and evolutionary branching within migratory populations.

    PubMed

    Torney, Colin J; Levin, Simon A; Couzin, Iain D

    2010-11-23

    Understanding the mechanisms that drive specialization and speciation within initially homogeneous populations is a fundamental challenge for evolutionary theory. It is an issue of relevance for significant open questions in biology concerning the generation and maintenance of biodiversity, the origins of reciprocal cooperation, and the efficient division of labor in social or colonial organisms. Several mathematical frameworks have been developed to address this question and models based on evolutionary game theory or the adaptive dynamics of phenotypic mutation have demonstrated the emergence of polymorphic, specialized populations. Here we focus on a ubiquitous biological phenomenon, migration. Individuals in our model may evolve the capacity to detect and follow an environmental cue that indicates a preferred migration route. The strategy space is defined by the level of investment in acquiring personal information about this route or the alternative tendency to follow the direction choice of others. The result is a relation between the migratory process and a game theoretic dynamic that is generally applicable to situations where information may be considered a public good. Through the use of an approximation of social interactions, we demonstrate the emergence of a stable, polymorphic population consisting of an uninformed subpopulation that is dependent upon a specialized group of leaders. The branching process is classified using the techniques of adaptive dynamics.

  6. Characterization of the branching patterns of glycogen branching enzyme truncated on the N-terminus.

    PubMed

    Devillers, Claire H; Piper, Mary E; Ballicora, Miguel A; Preiss, Jack

    2003-10-01

    Truncation of 112 amino acids at the N-terminus (Nd(1-112)) changes the chain transfer pattern of the Escherichia coli glycogen branching enzyme (GBE) [Arch. Biochem. Biophys. 397 (2002) 279]. We investigated further the role of the N-terminus by engineering other truncated GBEs and analyzing the branching pattern by high-performance anion-exchange chromatography. The wild type GBE transfers mainly chains with a degree of polymerization (d.p.) of 8-14, the Nd(1-112) enzyme transfers a greater proportion of chains with higher d.p. 15-20, whereas the 63- and 83-amino acid deleted enzymes had an intermediate pattern of transferred chains (d.p. 10-20). These data showed that a progressive shortening of the N-terminus leads to a gradual increase in the length of the transferred chains, suggesting that the N-terminus provides a support for the glucan substrate during the processes of cleavage and transfer of the alpha-(1-4) glucan chains.

  7. One-step synthesis of glucose-branched galactomannan.

    PubMed

    Gong, Peixin; Peng, Shuhua; He, Jianping; Deng, Mingyu; Jiang, Bo; Wang, Ke

    2011-09-27

    The synthesis of branched polysaccharides using naturally occurring materials has been reported since 1975, but applications of branched polysaccharides are relatively limited because of the long and complex modification processes. In this work, a practical and efficient procedure is presented that in one step levoglucosan can be grafted to galactomannan (at 115°C for 15h) with monochloroacetic acid as catalyst. The structural characteristics of the resulting substances were investigated by NMR spectroscopy. The MS (molar degree of substitution) of glucose was shown to gradually increase with the increase of the ratio of levoglucosan to galactomannan, and the maximal MS is 0.6. Levoglucosan units are mostly grafted to the C6-OH of the galactosyl residues in galactomannan, and the maximal percentage of the substituted C6-OH of galactosyl residues is 42.2%. The resulting levoglucosan tended to graft to the branching glucosyl residues of copolymers with an increase in MS, and the average length of the branching glucose is 3.6 when MS is 0.6. Copyright © 2011. Published by Elsevier Ltd.

  8. Pen Branch Delta and Savannah River Swamp Hydraulic Model

    SciTech Connect

    Chen, K.F.

    1999-05-13

    The proposed Savannah River Site (SRS) Wetlands Restoration Project area is located in Barnwell County, South Carolina on the southwestern boundary of the SRS Reservation. The swamp covers about 40.5 km2 and is bounded to the west and south by the Savannah River and to the north and east by low bluffs at the edge of the Savannah River floodplain. Water levels within the swamp are determined by stage along the Savannah River, local drainage, groundwater seepage, and inflows from four tributaries, Beaver Dam Creek, Fourmile Branch, Pen Branch, and Steel Creek. Historic discharges of heated process water into these tributaries scoured the streambed, created deltas in the adjacent wetland, and killed native vegetation in the vicinity of the delta deposits. Future releases from these tributaries will be substantially smaller and closer to ambient temperatures. One component of the proposed restoration project will be to reestablish indigenous wetland vegetation on the Pen Branch delta that covers about 1.0 km2. Long-term predictions of water levels within the swamp are required to determine the characteristics of suitable plants. The objective of the study was to predict water levels at various locations within the proposed SRS Wetlands Restoration Project area for a range of Savannah River flows and regulated releases from Pen Branch. TABS-MD, a United States Army Corps of Engineer developed two-dimensional finite element open channel hydraulic computer code, was used to model the SRS swamp area for various flow conditions.

  9. [The modern approaches to the organization of the expertize of the quality of medical care in the multi-type hospital].

    PubMed

    Breskina, T N

    2007-01-01

    The issue of revealing the risks ans losses applying the target analysis of every particular case with no expected outcome is discussed. The major role in the success of the total quality management system is played by factor of personnel attitude to searching and revealing the risks and losses at their own work places. The need to establish at the level of administrative management of the organization the system of motivating the personnel to actively participate in the process of controlling the losses and the resource economy in their working zone. The conclusion is made that the orientation towards the Heinrich Law actualizes the issue of revealing the risks (in public health it is the divergence from the technological standards) and the losses (i.e. the obvious defects in the curative diagnostic process). The implementation of the Heinrich Law inputs the technique of controlling the risks and the discrepancies (the deviations). Imminent is the need to modify the principles of the expertize of the total quality management, its optimization and transformation from the establishing system to effectual one targeted not to looking for and punishing the culpables but to elaborating the correctional and preventives activities for the purpose of minimizing the risks and continuous enhancing the processes.

  10. Branch architecture, light interception and crown development in saplings of a plagiotropically branching tropical tree, Polyalthia jenkinsii (Annonaceae).

    PubMed

    Osada, Noriyuki; Takeda, Hiroshi

    2003-01-01

    To investigate crown development patterns, branch architecture, branch-level light interception, and leaf and branch dynamics were studied in saplings of a plagiotropically branching tree species, Polyalthia jenkinsii Hk. f. & Thoms. (Annonaceae) in a Malaysian rain forest. Lengths of branches and parts of the branches lacking leaves ('bare' branches) were smaller in upper branches than in lower branches within crowns, whereas lengths of 'leafy' parts and the number of leaves per branch were larger in intermediate than in upper and lower branches. Maximum diffuse light absorption (DLA) of individual leaves was not related to sapling height or branch position within crowns, whereas minimum DLA was lower in tall saplings. Accordingly, branch-level light interception was higher in intermediate than in upper and lower branches. The leaf production rate was higher and leaf loss rate was smaller in upper than in intermediate and lower branches. Moreover, the branch production rate of new first-order branches was larger in the upper crowns. Thus, leaf and branch dynamics do not correspond to branch-level light interception in the different canopy zones. As a result of architectural constraints, branches at different vertical positions experience predictable light microenvironments in plagiotropic species. Accordingly, this pattern of carbon allocation among branches might be particularly important for growth and crown development in plagiotropic species.

  11. Ionic liquid-assisted synthesis of thorned gold plates comprising three-branched nanotip arrays.

    PubMed

    Qin, Yao; Song, Yin; Huang, Teng; Qi, Limin

    2011-03-14

    Hierarchically structured, thorned gold plates comprising regular, three-branched nanotip arrays were synthesized by a facile, one-pot reduction process in mixed solvents of the ionic liquid [BMIM][PF(6)] and formamide without additives.

  12. Universal properties of branching random walks in confined geometries

    NASA Astrophysics Data System (ADS)

    de Mulatier, C.; Mazzolo, A.; Zoia, A.

    2014-08-01

    Characterizing the occupation statistics of random walks through confined geometries amounts to assessing the distribution of the travelled length ℓ and the number of collisions n performed by the stochastic process in a given region, for which remarkably simple Cauchy-like formulas were established in the case of branching Pearson random walks with exponentially distributed jumps. In this letter, we derive two key results: first, we show that such formulas strikingly carry over to the much broader class of branching processes with arbitrary jumps, and have thus a universal character; second, we obtain a stronger version of these formulas relating the travelled length density and the collision density at any point of the phase space. Our results are key to such technological issues as the analysis of radiation flow for nuclear reactor design and medical diagnosis and apply more broadly to physical and biological systems with diffusion, reproduction and death.

  13. A tool for simulating parallel branch-and-bound methods

    NASA Astrophysics Data System (ADS)

    Golubeva, Yana; Orlov, Yury; Posypkin, Mikhail

    2016-01-01

    The Branch-and-Bound method is known as one of the most powerful but very resource consuming global optimization methods. Parallel and distributed computing can efficiently cope with this issue. The major difficulty in parallel B&B method is the need for dynamic load redistribution. Therefore design and study of load balancing algorithms is a separate and very important research topic. This paper presents a tool for simulating parallel Branchand-Bound method. The simulator allows one to run load balancing algorithms with various numbers of processors, sizes of the search tree, the characteristics of the supercomputer's interconnect thereby fostering deep study of load distribution strategies. The process of resolution of the optimization problem by B&B method is replaced by a stochastic branching process. Data exchanges are modeled using the concept of logical time. The user friendly graphical interface to the simulator provides efficient visualization and convenient performance analysis.

  14. Posterior Branches of Lumbar Spinal Nerves - Part I: Anatomy and Functional Importance.

    PubMed

    Kozera, Katarzyna; Ciszek, Bogdan

    2016-01-01

    The aim of this paper is to compare anatomic descriptions of posterior branches of the lumbar spinal nerves and, on this basis, present the location of these structures. The majority of anatomy textbooks do not describe these nerves in detail, which may be attributable to the fact that for many years they were regarded as structures of minor clinical importance. The state of knowledge on these nerves has changed within the last 30 years. Attention has been turned to their function and importance for both diagnostic practice and therapy of lower back pain. Summarising the available literature, we may conclude that the medial and lateral branches separate at the junction of the facet joint and the distal upper edge of the transverse process; that the size, course and area supplied differ between the lateral and the medial branch; and that facet joints receive multisegmental innervation. It has been demonstrated that medial branches are smaller than the respective lateral branches and they have a more constant course. Medial branches supply the area from the midline to the facet joint line, while lateral branches innervate tissues lateral to the facet joint. The literature indicates difficulties with determining specific anatomic landmarks relative to which the lateral branch and the distal medial branch can be precisely located. Irritation of sensory fibres within posterior branches of the lumbar spinal nerves may be caused by pathology of facet joints, deformity of the spine or abnormalities due to overloading or injury. The anatomic location and course of posterior branches of spinal nerves should be borne in mind to prevent damaging them during low-invasive analgesic procedures.

  15. [The synthesis of mathematical models of the branched axons and dendrites].

    PubMed

    Korogod, S M

    1988-01-01

    A mathematical apparatus of computer modelling was elaborated reflecting more completely the real morphological and electrophysiological features of axons and dendrites without restrictions and simplifications which were typical of the existing models of these structures. Equivalent electrical circuits of branching axons and dendrites were constructed with in-series and node connections of standard four-terminal networks corresponding to elementary segments with active or passive membrane. Basing on these circuits the equations were obtained describing electrical phenomena in branching neuronal processes. They were generalized for the case of multiple binary branching with arbitrary symmetry and geometry of the branches. A difference scheme common for the whole class of models under consideration was also constructed and an algorithm was elaborated for numerical solution of the obtained system of difference equations. The suggested model allows synthetizing a variety of models of branching axons and dendrites, that promotes the possibilities of model investigation of electrotonus, propagated excitation and their interactions.

  16. A critical role for NF2 and the Hippo pathway in branching morphogenesis.

    PubMed

    Reginensi, Antoine; Enderle, Leonie; Gregorieff, Alex; Johnson, Randy L; Wrana, Jeffrey L; McNeill, Helen

    2016-08-02

    Branching morphogenesis is a complex biological process common to the development of most epithelial organs. Here we demonstrate that NF2, LATS1/2 and YAP play a critical role in branching morphogenesis in the mouse kidney. Removal of Nf2 or Lats1/2 from the ureteric bud (UB) lineage causes loss of branching morphogenesis that is rescued by loss of one copy of Yap and Taz, and phenocopied by YAP overexpression. Mosaic analysis demonstrates that cells with high YAP expression have reduced contribution to UB tips, similar to Ret(-/-) cells, and that YAP suppresses RET signalling and tip identity. Conversely, Yap/Taz UB-deletion leads to cyst-like branching and expansion of UB tip markers, suggesting a shift towards tip cell identity. Based on these data we propose that NF2 and the Hippo pathway locally repress YAP/TAZ activity in the UB to promote subsequent splitting of the tip to allow branching morphogenesis.

  17. Early Asymptotic Giant Branch: Theory and Observations

    NASA Astrophysics Data System (ADS)

    Frantsman, Ju.

    1995-08-01

    While on the asymptotic giant branch (AGB), a star passes through two evolutionary phases: an early stage (E-AGB), and thermally pulsing AGB (TP-AGB). The theory of two AGB stages was developed more than a decade ago but till now some authors do not take into account the E-AGB phase in spite of the fact that E-AGB phase lasts for some stars considerably longer than the TP-AGB phase. The typical outcomes of such ignoration are shown in the report (wrong conclusions about the evolution of Large Magellanic Cloud, the mistakes in the determination of the ages of Magellanic Cloud clusters). The results are obtained using the "population simultaion" technique. The origin of some types of chemically peculiar stars is investigated (S-stars, faint carbon stars, carbon stars bluer and somewhat brighter than in the mean N-Type stars in the Magellanic Clouds). A suggestion is proposed that these stars are on the E-AGB evolutionary stage. They develop chemical peculiarities in the process of mass transfer in close binaries. It was assumed that during the TP-AGB phase, the primary (more massive) component, when being the carbon star, transfered the carbon enriched material by Roche-lobe overflow to the secondary component, which becomes the star with carbon overabundance. During the subsequent evolution the former secondary (and now after mass transfer carbon enriched) component reaches the E-AGB phase. The results of calculations are discussed and compared with observations.

  18. Synthesis of Biomimetic Branched Polymer Architectures

    NASA Astrophysics Data System (ADS)

    Marciel, Amanda; Mai, Danielle; Schroeder, Charles

    2014-03-01

    Development of sequence-defined or structurally-precise polymers as high-performance materials is a major challenge in materials science. In this work, we report a facile synthesis platform to produce monodisperse and stereochemically precise nucleotidomimetic polymers. Based on a top-down approach, we are able to precisely incorporate a wide-variety of functional group modifications in a simple two-step process. First, we utilize the natural ability of DNA polymerase to enzymatically incorporate chemically-modified monomers (e.g., C5-dibenzocyclooctyl dUTP) in a template-directed fashion. Second, we employ copper-free click chemistry to integrate the desired chemical functionality at precise locations along the polymer chain. In this way, we produced a variety of branched DNA homopolymer architectures including 3-arm star, symmetric H, and block-brush. Overall, this synthetic strategy allows for the systematic variation of oligomer length, stoichiometry, concentration, and environmental conditions to rapidly explore nucleotidomimetic polymer phase behavior for materials discovery.

  19. Code 672 observational science branch computer networks

    NASA Technical Reports Server (NTRS)

    Hancock, D. W.; Shirk, H. G.

    1988-01-01

    In general, networking increases productivity due to the speed of transmission, easy access to remote computers, ability to share files, and increased availability of peripherals. Two different networks within the Observational Science Branch are described in detail.

  20. Overview of the Advanced High Frequency Branch

    NASA Technical Reports Server (NTRS)

    Miranda, Felix A.

    2015-01-01

    This presentation provides an overview of the competencies, selected areas of research and technology development activities, and current external collaborative efforts of the NASA Glenn Research Center's Advanced High Frequency Branch.

  1. FY 1990 Applied Sciences Branch annual report

    SciTech Connect

    Keyes, B.M.; Dippo, P.C.

    1991-11-01

    The Applied Sciences Branch actively supports the advancement of DOE/SERI goals for the development and implementation of the solar photovoltaic technology. The primary focus of the laboratories is to provide state-of-the-art analytical capabilities for materials and device characterization and fabrication. The branch houses a comprehensive facility which is capable of providing information on the full range of photovoltaic components. A major objective of the branch is to aggressively pursue collaborative research with other government laboratories, universities, and industrial firms for the advancement of photovoltaic technologies. Members of the branch disseminate research findings to the technical community in publications and presentations. This report contains information on surface and interface analysis, materials characterization, development, electro-optical characterization module testing and performance, surface interactions and FTIR spectroscopy.

  2. Applied Aeroscience and CFD Branch Overview

    NASA Technical Reports Server (NTRS)

    LeBeau, Gerald J.; Kirk, Benjamin S.

    2014-01-01

    The principal mission of NASA Johnson Space Center is Human Spaceflight. In support of the mission the Applied Aeroscience and CFD Branch has several technical competencies that include aerodynamic characterization, aerothermodynamic heating, rarefied gas dynamics, and decelerator (parachute) systems.

  3. Sharing Fiscal Information: A Legislative Branch View.

    ERIC Educational Resources Information Center

    Rivlin, Alice M.

    1978-01-01

    Decisions regarding budget matters are complex; therefore, information sharing between the executive and legislative branches is helpful and necessary. Budget reforms have been initiated, but future trends indicate the need for flexibility and revision of information pathways. (MBR)

  4. Deoxycholate Bile Acid Directed Synthesis of Branched Au Nanostructures for Near Infrared Photothermal Ablation

    PubMed Central

    Kim, Dong-Hyun; Larson, Andrew C.

    2015-01-01

    We report an approach for simple, reproducible and high-yield synthesis of branched GNPs directed by deoxycholate bile acid supramolecular aggregates in Au solution. A growth process involving stepwise trapping of the GNP seeds and Au ions in the deoxycholate bile acid solution yields multiple-branched GNPs. Upon NIR laser irradiation strong NIR absorption for branched GNPs induced photothermal-heating to destroy tumor cells. Subsequently, these branched GNPs were bio-functionalized with cRGD cell penetrating-targeting peptides for photothermal cancer treatment applications. Branched GNPs conjugated with cRGD peptides enhanced internalization of the branched GNPs in BxPC3 human pancreatic adenocarcinoma cells and effectively ablated BxPC3 cells when irradiated with a NIR laser (808 nm). Their potential use as photothermal transducing agents was demonstrated in in vivo settings using a pancreatic cancer xenograft model. The tumors were effectively ablated with cRGD-branched GNPs injection and laser exposure without any observation of tumor recurrence. This firstly reported method for deoxycholate bile acid directed synthesis of branched GNPs opens new possibilities for the production of strong NIR absorbing nanostructures for selective nanophotothermolisys of cancer cells and the further design of novel materials with customized spectral and structural properties for broader applications. PMID:25934288

  5. Deoxycholate bile acid directed synthesis of branched Au nanostructures for near infrared photothermal ablation.

    PubMed

    Kim, Dong-Hyun; Larson, Andrew C

    2015-07-01

    We report an approach for simple, reproducible and high-yield synthesis of branched GNPs directed by deoxycholate bile acid supramolecular aggregates in Au solution. A growth process involving stepwise trapping of the GNP seeds and Au ions in the deoxycholate bile acid solution yields multiple-branched GNPs. Upon NIR laser irradiation strong NIR absorption for branched GNPs induced photothermal-heating to destroy tumor cells. Subsequently, these branched GNPs were biofunctionalized with cRGD cell penetrating-targeting peptides for photothermal cancer treatment applications. Branched GNPs conjugated with cRGD peptides enhanced internalization of the branched GNPs in BxPC3 human pancreatic adenocarcinoma cells and effectively ablated BxPC3 cells when irradiated with a NIR laser (808 nm). Their potential use as photothermal transducing agents was demonstrated in in vivo settings using a pancreatic cancer xenograft model. The tumors were effectively ablated with cRGD-branched GNPs injection and laser exposure without any observation of tumor recurrence. This firstly reported method for deoxycholate bile acid directed synthesis of branched GNPs opens new possibilities for the production of strong NIR absorbing nanostructures for selective nano-photothermolysis of cancer cells and the further design of novel materials with customized spectral and structural properties for broader applications. Copyright © 2015 Elsevier Ltd. All rights reserved.

  6. 12 CFR 5.70 - Federal branches and agencies.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... acquisition; (iv) Convert a state branch or state agency operated by a foreign bank, or a commercial lending company controlled by a foreign bank, into a Federal branch or agency; (v) Relocate a Federal branch or...

  7. Perivascular exudates in frosted branch angiitis.

    PubMed

    He, Lingmin; Moshfeghi, Darius M; Wong, Ira G

    2014-01-01

    Three cases of young, minimally symptomatic patients found to have vitritis and extensive perivenous vitreous exudates resembling frosted branch angiitis are presented. Optical coherence tomography showed that these exudates appear to be extravascated from the vasculature. The material persisted over 1 year on immunosuppressive therapy, suggesting that its resolution should not be a treatment end point. These cases add to our understanding of the spectrum of clinical findings in frosted branch angiitis.

  8. Title Sheet, National Home for Disabled Volunteer Soldiers, Northwestern Branch ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Title Sheet, National Home for Disabled Volunteer Soldiers, Northwestern Branch - National Home for Disabled Volunteer Soldiers, Northwestern Branch, 5000 West National Avenue, Milwaukee, Milwaukee County, WI

  9. Cdc42 regulates branching in angiogenic sprouting in vitro.

    PubMed

    Nguyen, Duc-Huy T; Gao, Lin; Wong, Alec; Chen, Christopher S

    2017-07-01

    The morphogenetic events that occur during angiogenic sprouting involve several members of the Rho family of GTPases, including Cdc42. However, the precise roles of Cdc42 in angiogenic sprouting have been difficult to elucidate owing to the lack of models to study these events in vitro. Here, we aim to identify the roles of Cdc42 in branching morphogenesis in angiogenesis. Using a 3D biomimetic model of angiogenesis in vitro, where endothelial cells were seeded inside a cylindrical channel within collagen gel and sprouted from the channel in response to a defined biochemical gradient of angiogenic factors, we inhibited Cdc42 activity with a small molecule inhibitor ML141 and examined the effects of Cdc42 on the morphogenetic processes of angiogenic sprouting. We find that partial inhibition of Cdc42 had minimal effects on directional migration of endothelial cells, but led to fewer branching events without affecting the length of these branches. We also observed that antagonizing Cdc42 reduced collective migration in favor of single cell migration. Additionally, Cdc42 also regulated the initiation of filopodial extensions in endothelial tip cells. Our findings suggest that Cdc42 can affect multiple morphogenetic processes during angiogenic sprouting and ultimately impact the architecture of the vasculature. © 2017 John Wiley & Sons Ltd.

  10. Northwestern Branch of Mangala Vallis

    NASA Technical Reports Server (NTRS)

    2002-01-01

    (Released 12 June 2002) The Science One of the many branches of the Mangala Vallis channel system is seen in this image. The water that likely carved the channels emerged from a huge graben or fracture almost 1000 km to the south. The THEMIS image shows where one of the channels exits the cratered highlands terrain onto the lowland plains. A bright scarp marks the transition between the two terrain types and demonstrates that in this location the highlands terrain is being eroded back. Note how the floor of the main channel appears to be at the same level as the lowland terrain, suggestive of a base level where erosion is no longer effective. Most of the steep slope faces in the image display darker slope streaks that are thought to be dust avalanche scars and indicate that a relatively thick mantle of dust is present in this region. Wind-sculpted ridges known as yardangs cover many of the surfaces throughout the area as shown by images from the Mars Global Surveyor mission. Most of them are at the limit of resolution in the THEMIS image but some are evident on the floor of the main channel at the point at which a smaller side channel enters. In this location they appear to extend right up to the base of the channel wall, giving the appearance that they are emerging from underneath the thick pile of material into which the channel is eroded. This suggests a geologic history in which a preexisting landscape of eroded yardangs was covered over by a thick pile of younger material that is now eroding back down to the original level. Alternatively, it is possible that the yardangs formed more recently at the abrupt transition between the channel floor and wall. More analysis is necessary to sort out the story. The Story This channel system is named 'Mangala,' the word for Mars in Sanskrit, a language of the Hindus of India that goes back more than 4,000 years, with written literature almost as long. Great epic tales have been written in this language, and Odyssey is

  11. Northwestern Branch of Mangala Vallis

    NASA Technical Reports Server (NTRS)

    2002-01-01

    (Released 12 June 2002) The Science One of the many branches of the Mangala Vallis channel system is seen in this image. The water that likely carved the channels emerged from a huge graben or fracture almost 1000 km to the south. The THEMIS image shows where one of the channels exits the cratered highlands terrain onto the lowland plains. A bright scarp marks the transition between the two terrain types and demonstrates that in this location the highlands terrain is being eroded back. Note how the floor of the main channel appears to be at the same level as the lowland terrain, suggestive of a base level where erosion is no longer effective. Most of the steep slope faces in the image display darker slope streaks that are thought to be dust avalanche scars and indicate that a relatively thick mantle of dust is present in this region. Wind-sculpted ridges known as yardangs cover many of the surfaces throughout the area as shown by images from the Mars Global Surveyor mission. Most of them are at the limit of resolution in the THEMIS image but some are evident on the floor of the main channel at the point at which a smaller side channel enters. In this location they appear to extend right up to the base of the channel wall, giving the appearance that they are emerging from underneath the thick pile of material into which the channel is eroded. This suggests a geologic history in which a preexisting landscape of eroded yardangs was covered over by a thick pile of younger material that is now eroding back down to the original level. Alternatively, it is possible that the yardangs formed more recently at the abrupt transition between the channel floor and wall. More analysis is necessary to sort out the story. The Story This channel system is named 'Mangala,' the word for Mars in Sanskrit, a language of the Hindus of India that goes back more than 4,000 years, with written literature almost as long. Great epic tales have been written in this language, and Odyssey is

  12. Broadening and shifting of the Raman Q branch of HD

    SciTech Connect

    Rosasco, G.J.; May, A.D.; Hurst, W.S.; Petway, L.B.; Smyth, K.C.

    1989-02-15

    The line broadening and shifting of the vibrational Q branch in pure HD has was measured for transitions J = 0 to 3 at room temperature over the density range 0.8 to 10.6 amagat. The shifting and broadening coefficients were determined with an uncertainty of + or - .0002/cm/amaget, which now provides a discriminating test for various semiclassical and quantal theoretical calculations. The line broadening coefficients are compared with linewidth data from other spectroscopic branches and with measurements of the rates of state-to-state rotational energy transfer. Use of an exponential gap law for the rates of rotational energy transfer allows estimates to be made of the contributions to the linewidths from rotationally inelastic, elastic vibrational dephasing, and elastic reorientation processes. This analysis suggests that rotational energy transfer occurs approximately 30% faster in v = 1 than in v = 0.

  13. Broadening and shifting of the Raman Q branch of HD

    SciTech Connect

    Rosasco, G.J.; May, A.D.; Hurst, W.S.; Petway, L.B.; Smyth, K.C.

    1989-02-15

    The line broadening and shifting of the vibrational Q branch in pure HD has been measured for transitions J = 0 to 3 at room temperature over the density range 0.8 to 10.6 amagat. The shifting and broadening coefficients have been determined with an uncertainty of +- 0.2 x 10/sup -3/ cm/sup -1/ /amagat, which now provides a discriminating test for various semiclassical and quantal theoretical calculations. The line broadening coefficients are compared with linewidth data from other spectroscopic branches and with measurements of the rates of state-to-state rotational energy transfer. Use of an exponential gap law for the rates of rotational energy transfer allows estimates to be made of the contributions to the linewidths from rotationally inelastic, elastic vibrational dephasing, and elastic reorientation processes. This analysis suggests that rotational energy transfer occurs approximately 30% faster in v = 1 than in v = 0.

  14. Higgs boson hadronic branching ratios at the ILC

    SciTech Connect

    Banda, Yambazi; Lastovicka, Tomas; Nomerotski, Andrei

    2010-08-01

    We present a study of the Higgs boson decay branching ratios to bb, cc, and gluons, one of the cornerstones of the physics program at the International Linear Collider. A standard model Higgs boson of 120 GeV mass, produced in the Higgs-strahlung process at {radical}(s)=250 GeV, was investigated using the full detector simulation and reconstruction procedures. The analysis was performed in the framework of the Silicon Detector concept with full account of inclusive standard model backgrounds. The selected decay modes contained two heavy flavor jets in the final state and required excellent flavor tagging through precise reconstruction of interaction and decay vertices in the detector. A new signal discrimination technique using correlations of neural network outputs was used to determine the branching ratios and estimate their uncertainties, 4.8%, 8.4%, and 12.2% for bb, cc, and gluons, respectively.

  15. Branch Architecture, Light Interception and Crown Development in Saplings of a Plagiotropically Branching Tropical Tree, Polyalthia jenkinsii (Annonaceae)

    PubMed Central

    OSADA, NORIYUKI; TAKEDA, HIROSHI

    2003-01-01

    To investigate crown development patterns, branch architecture, branch‐level light interception, and leaf and branch dynamics were studied in saplings of a plagiotropically branching tree species, Polyalthia jenkinsii Hk. f. & Thoms. (Annonaceae) in a Malaysian rain forest. Lengths of branches and parts of the branches lacking leaves (‘bare’ branches) were smaller in upper branches than in lower branches within crowns, whereas lengths of ‘leafy’ parts and the number of leaves per branch were larger in intermediate than in upper and lower branches. Maximum diffuse light absorption (DLA) of individual leaves was not related to sapling height or branch position within crowns, whereas minimum DLA was lower in tall saplings. Accordingly, branch‐level light interception was higher in intermediate than in upper and lower branches. The leaf production rate was higher and leaf loss rate was smaller in upper than in intermediate and lower branches. Moreover, the branch production rate of new first‐order branches was larger in the upper crowns. Thus, leaf and branch dynamics do not correspond to branch‐level light interception in the different canopy zones. As a result of architectural constraints, branches at different vertical positions experience predictable light microenvironments in plagiotropic species. Accordingly, this pattern of carbon allocation among branches might be particularly important for growth and crown development in plagiotropic species. PMID:12495920

  16. Structure-Property Relationships for Branched Worm-Like Micelles

    NASA Astrophysics Data System (ADS)

    Beaucage, Gregory; Rai, Durgesh

    2013-03-01

    Micellar solutions can display a wide range of phase structure as a function of counter ion content, surfactant concentration, and the presence of ternary components. Under some conditions, common to consumer products, extended cylindrical structures that display persistence and other chain features of polymers are produced. These worm-like micelles (WLMs) can form branched structures that dynamically change under shear and even in quiescent conditions. The rheology of these branched WLMs is strongly dependent on migration of the branch points, and the dynamics of branch formation and removal. Persistence and other polymer-based descriptions are also of importance. We have recently developed a scattering model for branched polyolefins and other topologically complex materials that can quantify the branching density, branch length, branch functionality and the hyperbranch (branch-on-branch) content of polymers. This work is being extended to study branching in WLMs in work coupled with Ron Larson at UMich to predict rheological properties.

  17. Use of branch and whole tree exposure systems to evaluate ozone impacts on forest trees

    SciTech Connect

    Schaap, W.

    1992-01-01

    An integrated research program was carried out to study the effects of ozone on physiological processes and growth of field-grown Douglas-fir saplings over a two year period (1989-1990). The main objective was to evaluate the use of branches as a means of scaling in air pollution research with a test of the hypothesis that branches can be treated as functionally independent units. This program was unique for a number of reasons, including (a) using >3.5 m tall saplings as opposed to seedlings and (b) experimentally separating the response of the whole tree from its parts (i.e. branches).

  18. Salivary Gland Branching Morphogenesis — Recent Progress and Future Opportunities

    PubMed Central

    Hsu, Jeff Chi-feng; Yamada, Kenneth M

    2010-01-01

    Salivary glands provide saliva to maintain oral health, and a loss of salivary gland function substantially decreases quality-of-life. Understanding the biological mechanisms that generate salivary glands during embryonic development may identify novel ways to regenerate function or design artificial salivary glands. This review article summarizes current research on the process of branching morphogenesis of salivary glands, which creates gland structure during development. We highlight exciting new advances and opportunities in studies of cell-cell interactions, mechanical forces, growth factors, and gene expression patterns to improve our understanding of this important process. PMID:21125789

  19. Damping by branching: a bioinspiration from trees.

    PubMed

    Theckes, B; Langre, E de; Boutillon, X

    2011-12-01

    Man-made slender structures are known to be sensitive to high levels of vibration due to their flexibility which often cause irreversible damage. In nature, trees repeatedly endure large amplitudes of motion, mostly caused by strong climatic events, yet with minor or no damage in most cases. A new damping mechanism inspired by the architecture of trees is identified here and characterized in the simplest tree-like structure, a Y-shaped branched structure. Through analytical and numerical analyses of a simple two-degree-of-freedom model, branching is shown to be the key ingredient in this protective mechanism that we call damping-by-branching. It originates in the geometrical nonlinearities so that it is specifically efficient to damp out large amplitudes of motion. A more realistic model, using flexible beam approximation, shows that the mechanism is robust. Finally, two bioinspired architectures are analyzed, showing significant levels of damping achieved via branching with typically 30% of the energy being dissipated in one oscillation. This concept of damping-by-branching is of simple practical use in the design of very slender and flexible structures subjected to extreme dynamical loadings.

  20. Technical activities of the configuration aeroelasticity branch

    NASA Technical Reports Server (NTRS)

    Cole, Stanley R. (Editor)

    1991-01-01

    A number of recent technical activities of the Configuration Aeroelasticity Branch of the NASA Langley Research Center are discussed in detail. The information on the research branch is compiled in twelve separate papers. The first of these topics is a summary of the purpose of the branch, including a full description of the branch and its associated projects and program efforts. The next ten papers cover specific projects and are as follows: Experimental transonic flutter characteristics of supersonic cruise configurations; Aeroelastic effects of spoiler surfaces mounted on a low aspect ratio rectangular wing; Planform curvature effects on flutter of 56 degree swept wing determined in Transonic Dynamics Tunnel (TDT); An introduction to rotorcraft testing in TDT; Rotorcraft vibration reduction research at the TDT; A preliminary study to determine the effects of tip geometry on the flutter of aft swept wings; Aeroelastic models program; NACA 0012 pressure model and test plan; Investigation of the use of extension twist coupling in composite rotor blades; and Improved finite element methods for rotorcraft structures. The final paper describes the primary facility operation by the branch, the Langley TDT.

  1. Visualization and force measurement of branching by Arp2/3 complex and N-WASP in actin filament.

    PubMed

    Fujiwara, Ikuko; Suetsugu, Shiro; Uemura, Sotaro; Takenawa, Tadaomi; Ishiwata, Shin'ichi

    2002-05-24

    To determine whether the Arp2/3 complex activated by N-WASP (VCA) branches actin filaments at the side (side branching), or at the barbed (B-)end (end branching) of the mother filaments, we have directly observed the branching process of actin filaments and examined single-molecule unbinding under optical microscope. We found that side branching was predominant, though not exclusive. At the initial stage of polymerization, the branching at the B-end occurred and subsequently the side branching started to occur. In either type of branching, the mother and daughter filaments elongated at nearly the same rate (growing type). Independently of the stage of polymerization, branching due to the direct coupling of filaments with an acute angle to the mother filaments (a coupling type) occurred. Phalloidin suppressed the growing type of branching but not the coupling type, implying that actin monomers are required for the former but not the latter. We found, by single molecule measurements using optical tweezers, that the Arp2/3 complex attaches to the side of actin filaments and the N-WASP appears to detach from the actin-Arp2/3 complex at 6-7 pN.

  2. Flight Planning Branch Space Shuttle Lessons Learned

    NASA Technical Reports Server (NTRS)

    Price, Jennifer B.; Scott, Tracy A.; Hyde, Crystal M.

    2011-01-01

    Planning products and procedures that allow the mission flight control teams and the astronaut crews to plan, train and fly every Space Shuttle mission have been developed by the Flight Planning Branch at the NASA Johnson Space Center. As the Space Shuttle Program ends, lessons learned have been collected from each phase of the successful execution of these Shuttle missions. Specific examples of how roles and responsibilities of console positions that develop the crew and vehicle attitude timelines will be discussed, as well as techniques and methods used to solve complex spacecraft and instrument orientation problems. Additionally, the relationships and procedural hurdles experienced through international collaboration have molded operations. These facets will be explored and related to current and future operations with the International Space Station and future vehicles. Along with these important aspects, the evolution of technology and continual improvement of data transfer tools between the shuttle and ground team has also defined specific lessons used in the improving the control teams effectiveness. Methodologies to communicate and transmit messages, images, and files from Mission Control to the Orbiter evolved over several years. These lessons have been vital in shaping the effectiveness of safe and successful mission planning that have been applied to current mission planning work in addition to being incorporated into future space flight planning. The critical lessons from all aspects of previous plan, train, and fly phases of shuttle flight missions are not only documented in this paper, but are also discussed as how they pertain to changes in process and consideration for future space flight planning.

  3. The Future of Washington's Branch Campuses. HECB Report on Branch Campus Development Plans-HB 2707

    ERIC Educational Resources Information Center

    Washington Higher Education Coordinating Board, 2005

    2005-01-01

    Washington's research university branch campuses were created in 1989 to increase opportunities for students in several regions of the state to complete their baccalaureate and graduate-level studies at public universities close to their homes. Currently, the University of Washington operates branch campuses in Bothell and Tacoma. The Bothell…

  4. Geometry optimization of branchings in vascular networks

    NASA Astrophysics Data System (ADS)

    Khamassi, Jamel; Bierwisch, Claas; Pelz, Peter

    2016-06-01

    Progress has been made in developing manufacturing technologies which enable the fabrication of artificial vascular networks for tissue cultivation. However, those networks are rudimentary designed with respect to their geometry. This restricts long-term biological functionality of vascular cells which depends on geometry-related fluid mechanical stimuli and the avoidance of vessel occlusion. In the present work, a bioinspired geometry optimization for branchings in artificial vascular networks has been conducted. The analysis could be simplified by exploiting self-similarity properties of the system. Design rules in the form of two geometrical parameters, i.e., the branching angle and the radius ratio of the daughter branches, are derived using the wall shear stress as command variable. The numerical values of these parameters are within the range of experimental observations. Those design rules are not only beneficial for tissue engineering applications. Moreover, they can be used as indicators for diagnoses of vascular diseases or for the layout of vascular grafts.

  5. Tillering and panicle branching genes in rice.

    PubMed

    Liang, Wei-hong; Shang, Fei; Lin, Qun-ting; Lou, Chen; Zhang, Jing

    2014-03-01

    Rice (Oryza sativa L.) is one of the most important staple food crops in the world, and rice tillering and panicle branching are important traits determining grain yield. Since the gene MONOCULM 1 (MOC 1) was first characterized as a key regulator in controlling rice tillering and branching, great progress has been achieved in identifying important genes associated with grain yield, elucidating the genetic basis of yield-related traits. Some of these important genes were shown to be applicable for molecular breeding of high-yielding rice. This review focuses on recent advances, with emphasis on rice tillering and panicle branching genes, and their regulatory networks. Copyright © 2013 Elsevier B.V. All rights reserved.

  6. Building Virtual Spaces for Children in the Digital Branch

    ERIC Educational Resources Information Center

    DuBroy, Michelle

    2010-01-01

    Purpose: A digital branch is just like a physical branch except that content is delivered digitally via the web. A digital branch has staff, a collection, a community, and a building. The purpose of this paper is to explore the concept of building individual spaces for different user groups, specifically children, within a digital branch.…

  7. 46 CFR 169.690 - Lighting branch circuits.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 7 2011-10-01 2011-10-01 false Lighting branch circuits. 169.690 Section 169.690... branch circuits. Each lighting branch circuit must meet the requirements of § 111.75-5 of this chapter... to a lighting distribution panelboard; and (b) Branch circuits in excess of 30 amperes may be...

  8. 46 CFR 169.690 - Lighting branch circuits.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 7 2012-10-01 2012-10-01 false Lighting branch circuits. 169.690 Section 169.690... branch circuits. Each lighting branch circuit must meet the requirements of § 111.75-5 of this chapter... to a lighting distribution panelboard; and (b) Branch circuits in excess of 30 amperes may be...

  9. 46 CFR 169.690 - Lighting branch circuits.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 7 2013-10-01 2013-10-01 false Lighting branch circuits. 169.690 Section 169.690... branch circuits. Each lighting branch circuit must meet the requirements of § 111.75-5 of this chapter... to a lighting distribution panelboard; and (b) Branch circuits in excess of 30 amperes may be...

  10. 46 CFR 169.690 - Lighting branch circuits.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 7 2014-10-01 2014-10-01 false Lighting branch circuits. 169.690 Section 169.690... branch circuits. Each lighting branch circuit must meet the requirements of § 111.75-5 of this chapter... to a lighting distribution panelboard; and (b) Branch circuits in excess of 30 amperes may be...

  11. 46 CFR 169.690 - Lighting branch circuits.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Lighting branch circuits. 169.690 Section 169.690... branch circuits. Each lighting branch circuit must meet the requirements of § 111.75-5 of this chapter... to a lighting distribution panelboard; and (b) Branch circuits in excess of 30 amperes may be...

  12. Building Virtual Spaces for Children in the Digital Branch

    ERIC Educational Resources Information Center

    DuBroy, Michelle

    2010-01-01

    Purpose: A digital branch is just like a physical branch except that content is delivered digitally via the web. A digital branch has staff, a collection, a community, and a building. The purpose of this paper is to explore the concept of building individual spaces for different user groups, specifically children, within a digital branch.…

  13. CsRAV1 induces sylleptic branching in hybrid poplar.

    PubMed

    Moreno-Cortés, Alicia; Hernández-Verdeja, Tamara; Sánchez-Jiménez, Paloma; González-Melendi, Pablo; Aragoncillo, Cipriano; Allona, Isabel

    2012-04-01

    • Sylleptic branching in trees may increase significantly branch number, leaf area and the general growth of the tree, particularly in its early years. Although this is a very important trait, so far little is known about the genes that control this process. • This article characterizes the Castanea sativa RAV1 gene, homologous to Arabidopsis TEM genes, by analyzing its circadian behavior and examining its winter expression in chestnut stems and buds. Transgenic hybrid poplars over-expressing CsRAV1 or showing RNA interference down-regulated PtaRAV1 and PtaRAV2 expression were produced and analyzed. • Over-expression of the CsRAV1 gene induces the early formation of sylleptic branches in hybrid poplar plantlets during the same growing season in which the lateral buds form. Only minor growth differences and no changes in wood anatomy are produced. • The possibility of generating trees with a greater biomass by manipulating the CsRAV1 gene makes CsRAV1 transgenic plants promising candidates for bioenergy production. © 2012 The Authors. New Phytologist © 2012 New Phytologist Trust.

  14. On the red giant branch mass loss in 47 Tucanae: Constraints from the horizontal branch morphology

    NASA Astrophysics Data System (ADS)

    Salaris, Maurizio; Cassisi, Santi; Pietrinferni, Adriano

    2016-05-01

    We obtain stringent constraints on the actual efficiency of mass loss for red giant branch stars in the Galactic globular cluster 47 Tuc, by comparing synthetic modelling based on stellar evolution tracks with the observed distribution of stars along the horizontal branch in the colour-magnitude-diagram. We confirm that the observed, wedge-shaped distribution of the horizontal branch can only be reproduced by accounting for a range of initial He abundances, in agreement with inferences from the analysis of the main sequence, and a red giant branch mass loss with a small dispersion. We carefully investigated several possible sources of uncertainty that could affect the results of the horizontal branch modelling, stemming from uncertainties in both stellar model computations and cluster properties, such as heavy element abundances, reddening, and age. We determine a firm lower limit of ~0.17M⊙ for the mass lost by red giant branch stars, corresponding to horizontal branch stellar masses between ~0.65M⊙ and ~0.73M⊙ (the range driven by the range of initial helium abundances). We also derive that in this cluster the amount of mass lost along the asymptotic giant branch stars is comparable to the mass lost during the previous red giant branch phase. These results confirm, for this cluster, the disagreement between colour-magnitude-diagram analyses and inferences from recent studies of the dynamics of the cluster stars, which predict a much less efficient red giant branch mass loss. A comparison between the results from these two techniques applied to other clusters is required to gain more insights about the origin of this disagreement.

  15. Crack branching in carbon steel. Fracture mechanisms

    NASA Astrophysics Data System (ADS)

    Syromyatnikova, A. S.; Alekseev, A. A.; Levin, A. I.; Lyglaev, A. V.

    2010-04-01

    The fracture surfaces of pressure vessels made of carbon steel that form during crack branching propagation are examined by fractography. Crack branching is found to occur at a crack velocity higher than a certain critical value V > V c . In this case, the material volume that is involved in fracture and depends on the elastoplastic properties of the material and the sample width has no time to dissipate the energy released upon crack motion via the damage mechanisms intrinsic in the material under given deformation conditions (in our case, via cracking according to intragranular cleavage).

  16. [Croatian Medical Association--Branch Slavonski Brod].

    PubMed

    Mahovne, Zvonimir

    2014-01-01

    The branch of the Croatian Medical Association in Slav. Brod was founded in 1953. The economic and social progress in subsequent years led to the increased number of health institutions, health professionals and owing to their activity to better health care. The branch survived very difficult war years from 1991 to 1995. Our members treated thousands of wounded and ill and gave the best of their skill and humanity. In the last decade our members took part in educational and scientific activities of School of Medicine, J. J. Strossmayer University in Osijek.

  17. Bayesian long branch attraction bias and corrections.

    PubMed

    Susko, Edward

    2015-03-01

    Previous work on the star-tree paradox has shown that Bayesian methods suffer from a long branch attraction bias. That work is extended to settings involving more taxa and partially resolved trees. The long branch attraction bias is confirmed to arise more broadly and an additional source of bias is found. A by-product of the analysis is methods that correct for biases toward particular topologies. The corrections can be easily calculated using existing Bayesian software. Posterior support for a set of two or more trees can thus be supplemented with corrected versions to cross-check or replace results. Simulations show the corrections to be highly effective.

  18. Branching model for vegetation. [polarimetric remote sensing

    NASA Technical Reports Server (NTRS)

    Yueh, Simon H.; Kong, J. A.; Jao, Jen K.; Shin, Robert T.; Le Toan, Thuy

    1992-01-01

    In the present branching model for remote sensing of vegetation, the frequency and angular responses of a two-scale cylinder cluster are calculated to illustrate the importance of vegetation architecture. Attention is given to the implementation of a two-scale branching model for soybeans, where the relative location of soybean plants is described by a pair of distribution functions. Theoretical backscattering coefficients evaluated by means of hole-correction pair distribution are in agreement with extensive data collected from soybean fields. The hole-correction approximation is found to be the more realistic.

  19. Ecological effects of contaminants in McCoy Branch, 1991--1993

    SciTech Connect

    Ryon, M.G.

    1996-09-01

    The 1984 Hazardous and Solid Waste Amendments to the Resource Conservation and Recovery Act (RCRA) required assessment of all current and former solid waste management units. Following guidelines under RCRA and the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA), a remedial investigation (RI) was required of the Y-12 Plant for their filled coal ash pond (FCAP) and associated areas on McCoy Branch. The RI process was initiated and assessments were presented. Because the disposal of coal ash in the ash pond, McCoy Branch, and Rogers Quarry was not consistent with the Tennessee Water Quality Act, several remediation steps were implemented between 1986 and 1994 for McCoy Branch to address disposal problems. The required ecological risk assessments of McCoy Branch watershed included provisions for biological monitoring of the watershed. The objectives of the biological monitoring were to (1) document changes in biological quality of McCoy Branch after completion of a pipeline bypassing upper McCoy Branch and further, after termination of all discharges to Rogers Quarry, (2) provide guidance on the need for additional remediation, and (3) evaluate the effectiveness of implemented remedial actions. The data from the biological monitoring program may also determine whether the goals of protection of human health and the environment of McCoy Branch are being accomplished.

  20. Sox9 plays multiple roles in the lung epithelium during branching morphogenesis.

    PubMed

    Rockich, Briana E; Hrycaj, Steven M; Shih, Hung Ping; Nagy, Melinda S; Ferguson, Michael A H; Kopp, Janel L; Sander, Maike; Wellik, Deneen M; Spence, Jason R

    2013-11-19

    Lung branching morphogenesis is a highly orchestrated process that gives rise to the complex network of gas-exchanging units in the adult lung. Intricate regulation of signaling pathways, transcription factors, and epithelial-mesenchymal cross-talk are critical to ensuring branching morphogenesis occurs properly. Here, we describe a role for the transcription factor Sox9 during lung branching morphogenesis. Sox9 is expressed at the distal tips of the branching epithelium in a highly dynamic manner as branching occurs and is down-regulated starting at embryonic day 16.5, concurrent with the onset of terminal differentiation of type 1 and type 2 alveolar cells. Using epithelial-specific genetic loss- and gain-of-function approaches, our results demonstrate that Sox9 controls multiple aspects of lung branching. Fine regulation of Sox9 levels is required to balance proliferation and differentiation of epithelial tip progenitor cells, and loss of Sox9 leads to direct and indirect cellular defects including extracellular matrix defects, cytoskeletal disorganization, and aberrant epithelial movement. Our evidence shows that unlike other endoderm-derived epithelial tissues, such as the intestine, Wnt/β-catenin signaling does not regulate Sox9 expression in the lung. We conclude that Sox9 collectively promotes proper branching morphogenesis by controlling the balance between proliferation and differentiation and regulating the extracellular matrix.

  1. Proteomic analysis of etiolated juvenile tetraploid Robinia pseudoacacia branches during different cutting periods.

    PubMed

    Lu, Nan; Xu, Zhaohe; Meng, Bingnan; Sun, Yuhan; Zhang, Jiangtao; Wang, Shaoming; Li, Yun

    2014-04-21

    The propagation of hard-branch cuttings of tetraploid Robinia pseudoacacia (black locust) is restricted by the low rooting rate; however, etiolated juvenile tetraploid black locust branches result in a significantly higher rooting rate of cuttings compared with non-etiolated juvenile tetraploid branches. To identify proteins that influence the juvenile tetraploid branch rooting process, two-dimensional electrophoresis (2-DE) and matrix-assisted laser desorption/ionization time-of-flight/time-of-flight mass spectra (MALDI-TOF/TOF-MS) were used to analyze proteomic differences in the phloem of tetraploid R. pseudoacacia etiolated and non-etiolated juvenile branches during different cutting periods. A total of 58 protein spots differed in expression level, and 16 protein spots were only expressed in etiolated branches or non-etiolated ones. A total of 40 highly expressed protein spots were identified by mass spectrometry, 14 of which were accurately retrieved. They include nucleoglucoprotein metabolic proteins, signaling proteins, lignin synthesis proteins and phyllochlorin. These results help to reveal the mechanism of juvenile tetraploid R. pseudoacacia etiolated branch rooting and provide a valuable reference for the improvement of tetraploid R. pseudoacacia cutting techniques.

  2. Modeling of dynamic crack branching by enhanced extended finite element method

    NASA Astrophysics Data System (ADS)

    Xu, Dandan; Liu, Zhanli; Liu, Xiaoming; Zeng, Qinglei; Zhuang, Zhuo

    2014-08-01

    The conventional extended finite element method (XFEM) is enhanced in this paper to simulate dynamic crack branching, which is a top challenge issue in fracture mechanics and finite element method. XFEM uses the enriched shape functions with special characteristics to represent the discontinuity in computation field. In order to describe branched cracks, it is necessary to set up the additional enrichment. Here we have developed two kinds of branched elements, namely the "element crossed by two separated cracks" and "element embedded by a junction". Another series of enriched degrees of freedom are introduced to seize the additional discontinuity in the elements. A shifted enrichment scheme is used to avoid the treatment of blending element. Correspondingly a new mass lumping method is developed for the branched elements based on the kinetic conservation. The derivation of the mass matrix of a four-node quadrilateral element which contains two strong discontinuities is specially presented. Then by choosing crack speed as the branching criterion, the branching process of a single mode I crack is simulated. The results including the branching angle and propagation routes are compared with that obtained by the conventionally used element deletion method.

  3. Proteomic Analysis of Etiolated Juvenile Tetraploid Robinia pseudoacacia Branches during Different Cutting Periods

    PubMed Central

    Lu, Nan; Xu, Zhaohe; Meng, Bingnan; Sun, Yuhan; Zhang, Jiangtao; Wang, Shaoming; Li, Yun

    2014-01-01

    The propagation of hard-branch cuttings of tetraploid Robinia pseudoacacia (black locust) is restricted by the low rooting rate; however, etiolated juvenile tetraploid black locust branches result in a significantly higher rooting rate of cuttings compared with non-etiolated juvenile tetraploid branches. To identify proteins that influence the juvenile tetraploid branch rooting process, two-dimensional electrophoresis (2-DE) and matrix-assisted laser desorption/ionization time-of-flight/time-of-flight mass spectra (MALDI-TOF/TOF-MS) were used to analyze proteomic differences in the phloem of tetraploid R. pseudoacacia etiolated and non-etiolated juvenile branches during different cutting periods. A total of 58 protein spots differed in expression level, and 16 protein spots were only expressed in etiolated branches or non-etiolated ones. A total of 40 highly expressed protein spots were identified by mass spectrometry, 14 of which were accurately retrieved. They include nucleoglucoprotein metabolic proteins, signaling proteins, lignin synthesis proteins and phyllochlorin. These results help to reveal the mechanism of juvenile tetraploid R. pseudoacacia etiolated branch rooting and provide a valuable reference for the improvement of tetraploid R. pseudoacacia cutting techniques. PMID:24756090

  4. Branching out with filmless radiology.

    PubMed

    Carbajal, R; Honea, R

    1999-05-01

    Texas Children's Hospital, a 456 bed pediatric hospital located in the Texas Medical Center, has been constructing a large-scale picture archiving and communications system (PACS), including ultrasound (US), computed tomography (CT), magnetic resonance (MR), and computed radiography (CR). Until recently, filmless radiology operations have been confined to the imaging department, the outpatient treatment center, and the emergency center. As filmless services expand to other clinical services, the PACS staff must engage each service in a dialog to determine the appropriate level of support required. The number and type of image examinations, the use of multiple modalities and comparison examinations, and the relationship between viewing and direct patient care activities have a bearing on the number and type of display stations provided. Some of the information about customer services is contained in documentation already maintained by the imaging department. For example, by a custom report from the radiology information system (RIS), we were able to determine the number and type of examinations ordered by each referring physician for the previous 6 months. By compiling these by clinical service, we were able to determine our biggest customers by examination type and volume. Another custom report was used to determine who was requesting old examinations from the film library. More information about imaging usage was gathered by means of a questionnaire. Some customers view images only where patients are also seen, while some services view images independently from the patient. Some services use their conference rooms for critical image viewing such as treatment planning. Additional information was gained from geographical surveys of where films are currently produced, delivered by the film library, and viewed. In some areas, available space dictates the type and configuration of display station that can be used. Active participation in the decision process by the

  5. Sieving di-branched from mono-branched and linear alkanes using ZIF-8: experimental proof and theoretical explanation.

    PubMed

    Ferreira, Alexandre F P; Mittelmeijer-Hazeleger, Marjo C; Granato, Miguel Angelo; Martins, Vanessa F Duarte; Rodrigues, Alírio E; Rothenberg, Gadi

    2013-06-14

    We study the adsorption equilibrium isotherms and differential heats of adsorption of hexane isomers on the zeolitic imidazolate framework ZIF-8. The studies are carried out at 373 K using a manometric set-up combined with a micro-calorimeter. We see that the Langmuir model describes well the isotherms for all four isomers (n-hexane, 2-methylpentane, 2,2-dimethylbutane and 2,3-dimethylbutane). The linear and mono-branched isomers adsorb well, but 2,2-dimethylbutane is totally excluded. Plotting the differential heat of adsorption against the loading shows an initial plateau for n-hexane and 2-methylpentane. This is followed by a slow rise, indicating adsorbate-adsorbate interactions. For the di-branched isomers the differential heat of adsorption decreases with loading. To gain further insight, we ran molecular simulations using the grand-canonical Monte Carlo approach. Comparing the simulation and the experimental results shows that the ZIF framework model requires blocking of the cages, since 2,2-dimethylbutane cannot fit through the sodalite-type windows. Practically speaking, this means that ZIF-8 is a highly promising candidate for enhancing gasoline octane numbers at 373 K, as it can separate 2,2-dimethylbutane and 2,3-dimethylbutane from 2-methylpentane. Our results prove the potential of ZIF-8 as a new adsorbent that can be employed in the upgrade of the Total Isomerization Process for the production of high octane number gasoline, by blending di-branched alkanes in the gasoline.

  6. Branched Motifs Enable Long-Range Interactions in Signaling Networks through Retrograde Propagation

    PubMed Central

    Jesan, Tharmaraj; Sarma, Uddipan; Halder, Subhadra; Saha, Bhaskar; Sinha, Sitabhra

    2013-01-01

    Branched structures arise in the intra-cellular signaling network when a molecule is involved in multiple enzyme-substrate reaction cascades. Such branched motifs are involved in key biological processes, e.g., immune response activated by T-cell and B-cell receptors. In this paper, we demonstrate long-range communication through retrograde propagation between branches of signaling pathways whose molecules do not directly interact. Our numerical simulations and experiments on a system comprising branches with JNK and p38MAPK as terminal molecules respectively that share a common MAP3K enzyme MEKK3/4 show that perturbing an enzyme in one branch can result in a series of changes in the activity levels of molecules “upstream” to the enzyme that eventually reaches the branch-point and affects other branches. In the absence of any evidence for explicit feedback regulation between the functionally distinct JNK and p38MAPK pathways, the experimentally observed modulation of phosphorylation amplitudes in the two pathways when a terminal kinase is inhibited implies the existence of long-range coordination through retrograde information propagation previously demonstrated in single linear reaction pathways. An important aspect of retrograde propagation in branched pathways that is distinct from previous work on retroactivity focusing exclusively on single chains is that varying the type of perturbation, e.g., between pharmaceutical agent mediated inhibition of phosphorylation or suppression of protein expression, can result in opposing responses in the other branches. This can have potential significance in designing drugs targeting key molecules which regulate multiple pathways implicated in systems-level diseases such as cancer and diabetes. PMID:23741327

  7. Multicomponent Synthesis of α-Branched Amides

    PubMed Central

    DeBenedetto, Mikkel V.; Green, Michael E.; Wan, Shuangyi; Park, Jung-Hyun; Floreancig, Paul E.

    2009-01-01

    α-Branched amides are prepared by multicomponent reactions in which nitriles undergo hydrozirconation to form metalloimines that react with acyl chlorides. The resulting acylimines react with a variety of π-nucleophiles in the presence of Lewis acids to form the desired amides. PMID:19152262

  8. Re-Envisioning New York's Branch Libraries

    ERIC Educational Resources Information Center

    Giles, David; Estima, Jeanette; Francois, Noelle

    2014-01-01

    Nearly two years ago, the Center for an Urban Future published "Branches of Opportunity," a report documenting that New York City's public libraries have become more vital than ever, and are serving more New Yorkers in more ways than ever before. This new report provides an exhaustive analysis of the libraries' capital needs and offers a…

  9. Academic Branch Libraries: Assessment and Collection Development

    ERIC Educational Resources Information Center

    Poole, Julie

    2009-01-01

    An ongoing project at Mercer University's Regional Academic Center Libraries illustrates how utilizing established assessment guidelines, stakeholder input, and a clear understanding of audience and curriculum needs may all be used to optimize a collection. Academic branch libraries often have clear collection development limitations in terms of…

  10. Branching instability in expanding bacterial colonies

    PubMed Central

    Giverso, Chiara; Verani, Marco; Ciarletta, Pasquale

    2015-01-01

    Self-organization in developing living organisms relies on the capability of cells to duplicate and perform a collective motion inside the surrounding environment. Chemical and mechanical interactions coordinate such a cooperative behaviour, driving the dynamical evolution of the macroscopic system. In this work, we perform an analytical and computational analysis to study pattern formation during the spreading of an initially circular bacterial colony on a Petri dish. The continuous mathematical model addresses the growth and the chemotactic migration of the living monolayer, together with the diffusion and consumption of nutrients in the agar. The governing equations contain four dimensionless parameters, accounting for the interplay among the chemotactic response, the bacteria–substrate interaction and the experimental geometry. The spreading colony is found to be always linearly unstable to perturbations of the interface, whereas branching instability arises in finite-element numerical simulations. The typical length scales of such fingers, which align in the radial direction and later undergo further branching, are controlled by the size parameters of the problem, whereas the emergence of branching is favoured if the diffusion is dominant on the chemotaxis. The model is able to predict the experimental morphologies, confirming that compact (resp. branched) patterns arise for fast (resp. slow) expanding colonies. Such results, while providing new insights into pattern selection in bacterial colonies, may finally have important applications for designing controlled patterns. PMID:25652464

  11. Branch President gives evidence at Scottish Parliament.

    PubMed

    2017-07-01

    As the Scottish Government moves forward with its recently announced package of measures on animal health and welfare, Hayley Atkin, BVA Policy Officer, describes a busy month for the President of BVA Scottish Branch representing members in the Scottish Parliament. British Veterinary Association.

  12. Laughter-induced left bundle branch block.

    PubMed

    Chow, Grant V; Desai, Dipan; Spragg, David D; Zakaria, Sammy

    2012-10-01

    We present the case of a patient with ischemic heart disease and intermittent left bundle branch block, reproducibly induced by laughter. Following treatment of ischemia with successful deployment of a drug-eluting stent, no further episodes of inducible LBBB were seen. Transient ischemia, exacerbated by elevated intrathoracic pressure during laughter, may have contributed to onset of this phenomenon.

  13. Genetic interactions underlying tree branch orientation

    USDA-ARS?s Scientific Manuscript database

    Expanding our understanding of the molecular and genetic mechanisms behind branch orientation in trees both addresses a fundamental developmental phenomenon and can lead to significant impacts on tree crop agriculture and forestry. Using the p-nome (pooled genome) sequencing-based mapping approac...

  14. Epicormic branching on pruned white fir

    Treesearch

    Richard D. Cosens

    1952-01-01

    Epicormic branches have developed on white fir (Abies concolor) one to two years after part of the live limbs were removed in a pruning experiment. The appearance of an average of six epicormic sprouts per tree raises some doubt as to the desirability of planting this species.

  15. Tribology and Mechanical Components Branch Overview

    NASA Technical Reports Server (NTRS)

    Handschuh, Robert F.

    2010-01-01

    An overview of NASA Glenn Research Center's Tribology & Mechanical Components Branch is provided. Work in space mechanisms, seals, oil-free turbomachinery, and mechanical components is presented. An overview of current research for these technology areas is contained in this overview.

  16. Characterization of branch complexity by fractal analyses

    USGS Publications Warehouse

    Alados, C.L.; Escos, J.; Emlen, J.M.; Freeman, D.C.

    1999-01-01

    The comparison between complexity in the sense of space occupancy (box-counting fractal dimension D(c) and information dimension D1) and heterogeneity in the sense of space distribution (average evenness index f and evenness variation coefficient J(cv)) were investigated in mathematical fractal objects and natural branch structures. In general, increased fractal dimension was paired with low heterogeneity. Comparisons between branch architecture in Anthyllis cytisoides under different slope exposure and grazing impact revealed that branches were more complex and more homogeneously distributed for plants on northern exposures than southern, while grazing had no impact during a wet year. Developmental instability was also investigated by the statistical noise of the allometric relation between internode length and node order. In conclusion, our study demonstrated that fractal dimension of branch structure can be used to analyze the structural organization of plants, especially if we consider not only fractal dimension but also shoot distribution within the canopy (lacunarity). These indexes together with developmental instability analyses are good indicators of growth responses to the environment.

  17. 12 CFR 741.11 - Foreign branching.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    .... (b) Contents of Application. The application must include a business plan, written approval by the...) Contents of Business Plan. The written business plan must address the following: (1) Analysis of market... regional director may revoke approval of the branch office for failure to follow the business plan in...

  18. 12 CFR 741.11 - Foreign branching.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    .... (b) Contents of Application. The application must include a business plan, written approval by the...) Contents of Business Plan. The written business plan must address the following: (1) Analysis of market... regional director may revoke approval of the branch office for failure to follow the business plan in...

  19. Detonation Structure Under Chain Branching Kinetics

    NASA Astrophysics Data System (ADS)

    Liang, Z.; Bauwens, L.

    2006-07-01

    Hydrogen-oxygen chemistry is characterized by a chain branching mechanism that yields three explosion limits. While a detailed kinetic scheme appropriate for hydrogen-oxygen should produce correct results, in many circumstances, a simpler yet reasonably realistic model will be warranted. In particular, it is easier to develop a clear understanding of the reaction zone structure using a simpler model, that includes only the key mechanisms. To that effect, we consider a four-step chain branching scheme that exhibits an explosion behavior with three limits, which behaves at least qualitatively like hydrogen chemistry. We focus in particular on the structure of the initiation and chain branching zones, using a combination between numerical simulation and analysis. Numerical simulations using this chemical model show distinctive keystone figures in the flow field, close to observations in hydrogen-oxygen detonation experiments. The structure of the chain branching zone is resolved using a perturbation analysis, which clarifies the differences between explosion and no-explosion regions and allows for an evaluation of the induction length in the steady wave. The analysis assumes both high activation energy and a slow initiation. Three cases are identified, respectively, with pressure and temperature located within the explosion region, close to the explosion limit and within the no-explosion region. The induction length is shorter and the reaction rate is faster by several orders of magnitude in the explosion region.

  20. Academic Branch Libraries: Assessment and Collection Development

    ERIC Educational Resources Information Center

    Poole, Julie

    2009-01-01

    An ongoing project at Mercer University's Regional Academic Center Libraries illustrates how utilizing established assessment guidelines, stakeholder input, and a clear understanding of audience and curriculum needs may all be used to optimize a collection. Academic branch libraries often have clear collection development limitations in terms of…

  1. Origin of buds, branches, and sprouts

    Treesearch

    Kevin T. Smith

    2014-01-01

    Recent research shows that survivor trees in rural, managed forests rebuild broken crowns with new branches and foliage after ice storm injury (Shortle et al. 2014). Veteran trees in historic parks and landscapes show repeated cycles of crown loss and recovery (Fay 2002). Crown rebuilding or reiteration from sprouts is a physiological response with architectural...

  2. ORD’s Urban Watershed Management Branch

    EPA Science Inventory

    This is a poster for the Edison Science Day, tentatively scheduled for June 10, 2009. This poster presentation summarizes key elements of the EPA Office of Research and Development’s (ORD) Urban Watershed Management Branch (UWMB). An overview of the national problems posed by w...

  3. National Museum of American History Branch Library.

    ERIC Educational Resources Information Center

    Ratner, Rhoda S.

    1986-01-01

    Subject concentration in the National Museum of American History Branch Library, a part of Smithsonian Institution Libraries system, is in the history of science and technology and American history, with emphasis on material culture and on documenting and servicing the museum's collections. Special collections include trade literature and…

  4. The AFCRL Lunar amd Planetary Research Branch

    NASA Astrophysics Data System (ADS)

    Price, Stephan D.

    2011-07-01

    The Lunar and Planetary research program led by Dr John (Jack) Salisbury in the 1960s at the United States Air Force Cambridge Research Laboratories (AFCRL) investigated the surface characteristics of Solar System bodies. The Branch was one of the first groups to measure the infrared spectra of likely surface materials in the laboratory under appropriate vacuum and temperature conditions. The spectral atlases created from the results were then compared to photometric and spectral measurements obtained from ground- and balloon-based telescopes to infer the mineral compositions and physical conditions of the regoliths of the Moon, Mars and asteroids. Starting from scratch, the Branch initially sponsored observations of other groups while its in-house facilities were being constructed. The earliest contracted efforts include the spatially-resolved mapping of the Moon in the first half of the 1960s by Richard W. Shorthill and John W. Saari of the Boeing Scientific Research Laboratories in Seattle. This effort ultimately produced isophotal and isothermal contour maps of the Moon during a lunation and time-resolved thermal images of the eclipsed Moon. The Branch also sponsored probe rocket-based experiments flown by Riccardo Giacconi and his group at American Science and Engineering Inc. that produced the first observations of X-ray stars in 1962 and later the first interferometric measurement of the ozone and C02 emission in the upper atmosphere. The Branch also made early use of balloon-based measurements. This was a singular set of experiments, as these observations are among the very few mid-infrared astronomical measurements obtained from a balloon platform. Notable results of the AFCRL balloon flights were the mid-infrared spectra of the spatially-resolved Moon obtained with the University of Denver mid-infrared spectrometer on the Branch's balloon-borne 61-cm telescope during a 1968 flight. These observations remain among the best available. Salisbury also funded

  5. Geodynamics branch data base for main magnetic field analysis

    NASA Technical Reports Server (NTRS)

    Langel, Robert A.; Baldwin, R. T.

    1991-01-01

    The data sets used in geomagnetic field modeling at GSFC are described. Data are measured and obtained from a variety of information and sources. For clarity, data sets from different sources are categorized and processed separately. The data base is composed of magnetic observatory data, surface data, high quality aeromagnetic, high quality total intensity marine data, satellite data, and repeat data. These individual data categories are described in detail in a series of notebooks in the Geodynamics Branch, GSFC. This catalog reviews the original data sets, the processing history, and the final data sets available for each individual category of the data base and is to be used as a reference manual for the notebooks. Each data type used in geomagnetic field modeling has varying levels of complexity requiring specialized processing routines for satellite and observatory data and two general routines for processing aeromagnetic, marine, land survey, and repeat data.

  6. Tree branching: Leonardo da Vinci's rule versus biomechanical models.

    PubMed

    Minamino, Ryoko; Tateno, Masaki

    2014-01-01

    This study examined Leonardo da Vinci's rule (i.e., the sum of the cross-sectional area of all tree branches above a branching point at any height is equal to the cross-sectional area of the trunk or the branch immediately below the branching point) using simulations based on two biomechanical models: the uniform stress and elastic similarity models. Model calculations of the daughter/mother ratio (i.e., the ratio of the total cross-sectional area of the daughter branches to the cross-sectional area of the mother branch at the branching point) showed that both biomechanical models agreed with da Vinci's rule when the branching angles of daughter branches and the weights of lateral daughter branches were small; however, the models deviated from da Vinci's rule as the weights and/or the branching angles of lateral daughter branches increased. The calculated values of the two models were largely similar but differed in some ways. Field measurements of Fagus crenata and Abies homolepis also fit this trend, wherein models deviated from da Vinci's rule with increasing relative weights of lateral daughter branches. However, this deviation was small for a branching pattern in nature, where empirical measurements were taken under realistic measurement conditions; thus, da Vinci's rule did not critically contradict the biomechanical models in the case of real branching patterns, though the model calculations described the contradiction between da Vinci's rule and the biomechanical models. The field data for Fagus crenata fit the uniform stress model best, indicating that stress uniformity is the key constraint of branch morphology in Fagus crenata rather than elastic similarity or da Vinci's rule. On the other hand, mechanical constraints are not necessarily significant in the morphology of Abies homolepis branches, depending on the number of daughter branches. Rather, these branches were often in agreement with da Vinci's rule.

  7. Dichotomous branching: the plant form and integrity upon the apical meristem bifurcation

    PubMed Central

    Gola, Edyta M.

    2014-01-01

    The division of the apical meristem into two independently functioning axes is defined as dichotomous branching. This type of branching typically occurs in non-vascular and non-seed vascular plants, whereas in seed plants it presents a primary growth form only in several taxa. Dichotomy is a complex process, which requires a re-organization of the meristem structure and causes changes in the apex geometry and activity. However, the mechanisms governing the repetitive apex divisions are hardly known. Here, an overview of dichotomous branching is presented, occurring in structurally different apices of phylogenetically distant plants, and in various organs (e.g., shoots, roots, rhizophores). Additionally, morphogenetic effects of dichotomy are reviewed, including its impact on organogenesis and mechanical constraints. At the end, the hormonal and genetic regulation of the dichotomous branching is discussed. PMID:24936206

  8. Absolute Measurement of Hadronic Branching Fractions of the D{sub s}{sup +} Meson

    SciTech Connect

    Alexander, J. P.; Berkelman, K.; Cassel, D. G.; Duboscq, J. E.; Ehrlich, R.; Fields, L.; Gibbons, L.; Gray, R.; Gray, S. W.; Hartill, D. L.; Heltsley, B. K.; Hertz, D.; Jones, C. D.; Kandaswamy, J.; Kreinick, D. L.; Kuznetsov, V. E.; Mahlke-Krueger, H.; Mohapatra, D.; Onyisi, P. U. E.; Patterson, J. R.

    2008-04-25

    The branching fractions of D{sub s}{sup {+-}} meson decays serve to normalize many measurements of processes involving charm quarks. Using 298 pb{sup -1} of e{sup +}e{sup -} collisions recorded at a center of mass energy of 4.17 GeV, we determine absolute branching fractions for eight D{sub s}{sup {+-}} decays with a double tag technique. In particular we determine the branching fraction B(D{sub s}{sup +}{yields}K{sup -}K{sup +}{pi}{sup +})=(5.50{+-}0.23{+-}0.16)%, where the uncertainties are statistical and systematic, respectively. We also provide partial branching fractions for kinematic subsets of the K{sup -}K{sup +}{pi}{sup +} decay mode.

  9. CFD Modelling of Local Hemodynamics in Intracranial Aneurysms Harboring Arterial Branches.

    PubMed

    Krylov, Vladimir; Grigoryeva, Elena; Dolotova, Daria; Blagosklonova, Evgenia; Gavrilov, Andrey

    2017-01-01

    The main cause of non-traumatic subarachnoid haemorrhage is an intracranial aneurysm's rupture. The choice of treatment approach is exceptionally difficult in cases of aneurysms with additional branches on the aneurysm's dome or neck. The impact of the arterial branches on local hemodynamics is still unclear and controversial question. At the same time, up-to-date methods of image processing and mathematical modeling provide a way to investigate the hemodynamic environment of aneurysms. The paper discusses hemodynamic aspects of aneurysms harboring arterial branch through the use of patient-specific 3D models and computational fluid dynamics (CFD) methods. The analysis showed that the presence of the arterial branches has a great influence on flow streamlines and wall shear stress, particularly for side wall aneurysm.

  10. Epitaxial self-assembly of binary molecular components into branched nanowire heterostructures for photonic applications.

    PubMed

    Kong, Qinghua; Liao, Qing; Xu, Zhenzhen; Wang, Xuedong; Yao, Jiannian; Fu, Hongbing

    2014-02-12

    We report a sequential epitaxial growth to prepare organic branched nanowire heterostructures (BNwHs) consisting of a microribbon trunk of 1,4-dimethoxy-2,5-di[4'-(cyano)styryl]benzene (COPV) with multiple nanowire branches of 2,4,5-triphenylimidazole (TPI) in a one-pot solution synthesis. The synthesis involves a seeded-growth process, where COPV microribbons are grown first as a trunk followed by a seeded-growth of TPI nanowire branches at the pregrown trunk surfaces. Selected area electron diffraction characterizations reveal that multiple hydrogen-bonding interactions between TPI and COPV components play an essential role in the epitaxial growth as a result of the structural matching between COPV and TPI crystals. A multichannel optical router was successfully realized on the basis of the passive waveguides of COPV green photoluminescence (PL) along TPI nanowire branches in a single organic BNwH.

  11. Bioreducible poly(amido amine)s with different branching degrees as gene delivery vectors.

    PubMed

    Zhang, Bo; Ma, Xinpeng; Murdoch, William; Radosz, Maciej; Shen, Youqing

    2013-03-01

    Based on the knowledge that cationic polymers with different topographical structures behave differently in gene transfection process, herein, we synthesized three biodegradable poly(amido amine)s (PAAs) with the same repeating units and molecular weights except for degree of branching: linear PAA (LPAA), low-branched PAA (LBPAA), and high-branched PAA (HBPAA). We found that LBPAA could more effectively compact pDNA into positively charged nanoparticles than both HBPAA and LPAA. LBPAA polyplexes had the highest transfection efficiency among the three PAA polyplexes, and the difference in transfection efficiency is mainly attributed to the endocytosis rate. The cytotoxicity of PAAs was negligible at the transfection doses, probably due to the degradable disulfide bonds. Therefore, we could use branching as a parameter to simply tune a polymer's cellular uptake behavior and transfection efficiency.

  12. CN and CH inhomogeneities among red horizontal branch stars in M71

    SciTech Connect

    Smith, G.H.; Penny, A.J.

    1989-05-01

    Spectra have been obtained of a sample of horizontal branch stars in the globular cluster M71. These display clear variations in the strengths of the 3883-A and 4215-A CN bands, with the former of these features showing a bimodal distribution. A clear anticorrelation exists between the strength of the 3883-A CN band and the CH absorption in the region of the 4300-A G band, indicating that part of the surface material of the CN-strong stars has been processed through the CN cycle of hydrogen burning. The percentage of CN-strong stars found on the horizontal branch is consistent with that observed by Smith and Norris (1982) on the giant branch of M71. Hence, there is no evidence from the available data that the percentage of these stars increases during the transition between the red giant and horizontal branch stages of evolution. 39 refs.

  13. The Branching Bifurcation of Adaptive Dynamics

    NASA Astrophysics Data System (ADS)

    Della Rossa, Fabio; Dercole, Fabio; Landi, Pietro

    2015-06-01

    We unfold the bifurcation involving the loss of evolutionary stability of an equilibrium of the canonical equation of Adaptive Dynamics (AD). The equation deterministically describes the expected long-term evolution of inheritable traits — phenotypes or strategies — of coevolving populations, in the limit of rare and small mutations. In the vicinity of a stable equilibrium of the AD canonical equation, a mutant type can invade and coexist with the present — resident — types, whereas the fittest always win far from equilibrium. After coexistence, residents and mutants effectively diversify, according to the enlarged canonical equation, only if natural selection favors outer rather than intermediate traits — the equilibrium being evolutionarily unstable, rather than stable. Though the conditions for evolutionary branching — the joint effect of resident-mutant coexistence and evolutionary instability — have been known for long, the unfolding of the bifurcation has remained a missing tile of AD, the reason being related to the nonsmoothness of the mutant invasion fitness after branching. In this paper, we develop a methodology that allows the approximation of the invasion fitness after branching in terms of the expansion of the (smooth) fitness before branching. We then derive a canonical model for the branching bifurcation and perform its unfolding around the loss of evolutionary stability. We cast our analysis in the simplest (but classical) setting of asexual, unstructured populations living in an isolated, homogeneous, and constant abiotic environment; individual traits are one-dimensional; intra- as well as inter-specific ecological interactions are described in the vicinity of a stationary regime.

  14. Environmental control of branching in petunia.

    PubMed

    Drummond, Revel S M; Janssen, Bart J; Luo, Zhiwei; Oplaat, Carla; Ledger, Susan E; Wohlers, Mark W; Snowden, Kimberley C

    2015-06-01

    Plants alter their development in response to changes in their environment. This responsiveness has proven to be a successful evolutionary trait. Here, we tested the hypothesis that two key environmental factors, light and nutrition, are integrated within the axillary bud to promote or suppress the growth of the bud into a branch. Using petunia (Petunia hybrida) as a model for vegetative branching, we manipulated both light quality (as crowding and the red-to-far-red light ratio) and phosphate availability, such that the axillary bud at node 7 varied from deeply dormant to rapidly growing. In conjunction with the phenotypic characterization, we also monitored the state of the strigolactone (SL) pathway by quantifying SL-related gene transcripts. Mutants in the SL pathway inhibit but do not abolish the branching response to these environmental signals, and neither signal is dominant over the other, suggesting that the regulation of branching in response to the environment is complex. We have isolated three new putatively SL-related TCP (for Teosinte branched1, Cycloidia, and Proliferating cell factor) genes from petunia, and have identified that these TCP-type transcription factors may have roles in the SL signaling pathway both before and after the reception of the SL signal at the bud. We show that the abundance of the receptor transcript is regulated by light quality, such that axillary buds growing in added far-red light have greatly increased receptor transcript abundance. This suggests a mechanism whereby the impact of any SL signal reaching an axillary bud is modulated by the responsiveness of these cells to the signal. © 2015 American Society of Plant Biologists. All Rights Reserved.

  15. Melatonin Inhibits Embryonic Salivary Gland Branching Morphogenesis by Regulating Both Epithelial Cell Adhesion and Morphology

    PubMed Central

    Miura, Jiro; Sakai, Manabu; Uchida, Hitoshi; Nakamura, Wataru; Nohara, Kanji; Maruyama, Yusuke; Hattori, Atsuhiko; Sakai, Takayoshi

    2015-01-01

    Many organs, including salivary glands, lung, and kidney, are formed by epithelial branching during embryonic development. Branching morphogenesis occurs via either local outgrowths or the formation of clefts that subdivide epithelia into buds. This process is promoted by various factors, but the mechanism of branching morphogenesis is not fully understood. Here we have defined melatonin as a potential negative regulator or “brake” of branching morphogenesis, shown that the levels of it and its receptors decline when branching morphogenesis begins, and identified the process that it regulates. Melatonin has various physiological functions, including circadian rhythm regulation, free-radical scavenging, and gonadal development. Furthermore, melatonin is present in saliva and may have an important physiological role in the oral cavity. In this study, we found that the melatonin receptor is highly expressed on the acinar epithelium of the embryonic submandibular gland. We also found that exogenous melatonin reduces salivary gland size and inhibits branching morphogenesis. We suggest that this inhibition does not depend on changes in either proliferation or apoptosis, but rather relates to changes in epithelial cell adhesion and morphology. In summary, we have demonstrated a novel function of melatonin in organ formation during embryonic development. PMID:25876057

  16. Controlled synthesis of hyper-branched inorganic nanocrystals withrich three-dimensional structures

    SciTech Connect

    Kanaras, Antonios G.; Sonnichsen, Carsten; Liu, Haitao; Alivisatos, A. Paul

    2005-07-27

    Studies of crystal growth kinetics are tightly integrated with advances in the creation of new nanoscale inorganic building blocks and their functional assemblies 1-11. Recent examples include the development of semiconductor nanorods which have potential uses in solar cells 12-17, and the discovery of a light driven process to create noble metal particles with sharp corners that can be used in plasmonics 18,19. In the course of studying basic crystal growth kinetics we developed a process for preparing branched semiconductor nanocrystals such as tetrapods and inorganic dendrimers of precisely controlled generation 20,21. Here we report the discovery of a crystal growth kinetics regime in which a new class of hyper-branched nanocrystals are formed. The shapes range from 'thorny balls', to tree-like ramified structures, to delicate 'spider net'-like particles. These intricate shapes depend crucially on a delicate balance of branching and extension. The multitudes of resulting shapes recall the diverse shapes of snowflakes 22.The three dimensional nature of the branch points here, however, lead to even more complex arrangements than the two dimensionally branched structures observed in ice. These hyper-branched particles not only extend the available three-dimensional shapes in nanoparticle synthesis ,but also provide a tool to study growth kinetics by carefully observing and modeling particle morphology.

  17. Reaction-diffusion-branching models of stock price fluctuations

    NASA Astrophysics Data System (ADS)

    Tang, Lei-Han; Tian, Guang-Shan

    Several models of stock trading (Bak et al., Physica A 246 (1997) 430.) are analyzed in analogy with one-dimensional, two-species reaction-diffusion-branching processes. Using heuristic and scaling arguments, we show that the short-time market price variation is subdiffusive with a Hurst exponent H=1/4. Biased diffusion towards the market price and blind-eyed copying lead to crossovers to the empirically observed random-walk behavior ( H=1/2) at long times. The calculated crossover forms and diffusion constants are shown to agree well with simulation data.

  18. Erosional Mechanics and the Structure of Branched Channel Networks

    NASA Astrophysics Data System (ADS)

    Shelef, E.; Hilley, G. E.

    2013-12-01

    Branched Channel Networks (BCNs) are among the most striking geometric forms that define the surface of our planet, as well as the surfaces of some other planets. These networks are typically arranged in a branched, tree-like plan-view configuration, where the along-flow profile of segments composing these features are concave-up such that the channel slope (S) and drainage area (A) are related to one another by the concavity θ as S ∝A^θ . While θ likely reflects the mechanics of channel forming process, it is not clear if and how these processes are related to the plan-view arrangement of BCNs. In fact, many topologic measures fail to distinguish the plan-view configuration of natural networks from those generated by random walks, and so it is unclear whether the geometric properties of BCNs reflect the action of specific surface processes or simply result from the interaction of flows with pre-existing topography. Here we demonstrate that the multi-scale plan-view structure of BCNs observed across our planet and expected from process-based simulations is unlikely to result from random-walk processes. Instead, we show that structure of BCNs reflects two coupled constraints: (a) the characteristic along-flow channel profile shaped by the channel forming processes (as reflected by the channel concavity; θ), and (b) the fact that two flows initiating at an infinitesimal distance apart on each side of a drainage divide must experience an identical elevation drop between the divide and the junction where these flows once again meet. We found that the degree to which these constraints are satisfied distinguishes random, natural, and modeled landscapes, and explains morphological differences between modeled landscapes of various concavities, as well as temporal changes in their plan-view network geometries. These plan-view forms may therefore divulge information about processes that transport mass across Earth's surface, and may reveal processes that sculpt BCNs on

  19. A path integral approach to age dependent branching processes

    NASA Astrophysics Data System (ADS)

    Greenman, Chris D.

    2017-03-01

    Age dependent population dynamics are frequently modeled with generalizations of the classic McKendrick–von Foerster equation. These are deterministic systems, and a stochastic generalization was recently reported in Greenman and Chou (2016 Phys. Rev. E 93 012112, 2016 J. Stat. Phys. 16449). Here we develop a fully stochastic theory for age-structured populations via quantum field theoretical Doi–Peliti techniques. This results in a path integral formulation where birth and death events correspond to cubic and quadratic interaction terms. This formalism allows us to efficiently recapitulate the results in Greenman and Chou (2016 Phys. Rev. E 93 012112, 2016 J. Stat. Phys. 16449), exemplifying the utility of Doi–Peliti methods. Furthermore, we find that the path integral formulation for age-structured moments has an exact perturbative expansion that explicitly relates to the hereditary structure between correlated individuals. These methods are then generalized with a binary fission model of cell division.

  20. Functional morphology, biomechanics and biomimetic potential of stem-branch connections in Dracaena reflexa and Freycinetia insignis.

    PubMed

    Masselter, Tom; Eckert, Sandra; Speck, Thomas

    2011-01-01

    Branching in plants is one of the most important assets for developing large arborescent growth forms with complex crowns. While the form and development of branching in gymnosperms and dicotyledonous trees is widely understood, very little is known about branching patterns and the structure of branch-stem-junctions in arborescent monocotyledons. For a better and quantitative understanding of the functional morphology of branch-stem-junctions in arborescent monocotyledons, we investigated the two species Dracaena reflexa and Freycinetia insignis. While D. reflexa is able to develop large arborescent forms with conspicuous crowns by anomalous secondary growth, F. insignis remains relatively small and is only capable of primary growth. Biomechanical investigations were performed by applying vertical loads up to rupture to lateral branches of both species. This allows the analysis of the fracture mechanics and the determination of the maximal force, stress and strain at rupture as well as the fracture toughness. Functional morphology was correlated with the mechanical behaviour of these plants and compared to data of other dicotyledonous trees. The high energy absorption found in the rupture process of lateral branches of D. reflexa and F. insignis makes them promising biological concept generators with a high potential for biomimetic implementation, i.e., for the development of branched fibre-reinforced technical composites. A wide range of constructional elements with branched (sub-)structures can be optimised by using solutions inspired by plant ramifications, e.g., in automotive and aerospace engineering, architecture, sports equipment and prosthetic manufacturing.

  1. Node-specific branching and heterochronic changes underlie population-level differences in Mimulus guttatus (Phrymaceae) shoot architecture.

    PubMed

    Baker, Robert L; Diggle, Pamela K

    2011-12-01

    Shoot architecture is a fundamentally developmental aspect of plant biology with implications for plant form, function, reproduction, and life history evolution. Mimulus guttatus is morphologically diverse and becoming a model for evolutionary biology. Shoot architecture, however, has never been studied from a developmental perspective in M. guttatus. We examined the development of branches and flowers in plants from two locally adapted populations of M. guttatus with contrasting flowering times, life histories, and branch numbers. We planted second-generation seed in growth chambers to control for maternal and environmental effects. Most branches occurred at nodes one and two of the main axis. Onset of branching occurred earlier and at a greater frequency in perennials than in annuals. In perennials, almost all flowers occurred at the fifth or more distal nodes. In annuals, most flowers occurred at the third and more distal nodes. Accessory axillary meristems and higher-order branching did not influence shoot architecture. We found no evidence for trade-offs between flowers and branches because axillary meristem number was not limiting: a large number of meristems remained quiescent. If, however, quiescence is a component of meristem allocation strategy, then meristems may be limited despite presence of quiescent meristems. At the two basalmost nodes, branch number was determined by mechanisms governing either meristem initiation or outgrowth, rather than flowering vs. branching. At the third and more distal nodes, heterochronic processes contributed to flowering time and branch number differences between populations.

  2. Photoinduced Acrylate Polymerization: Unexpected Reduction in Chain Branching.

    PubMed

    Wenn, Benjamin; Reekmans, Gunter; Adriaensens, Peter; Junkers, Thomas

    2015-08-01

    The branching stemming from midchain radical formation in n-butyl acrylate polymerization is investigated via melt-state (13) C NMR measurements. The dependence of the degree of branching (DB) on the monomer conversion of the system is examined for photoinduced polymerizations, revealing a steady increase in branching with conversion. For polymerization at moderate light intensities, an increase in branching from 0.03% to 0.37% is observed for polymerizations at 60 °C, which is fivefold below the level of branching observed in thermally initiated polymerizations under otherwise identical reaction conditions. The reason for this overall reduction in branching remains momentarily unclear; yet, a strong dependence of branching on light intensity is observed. While polymerization under a 1 W LED lamp results at almost full monomer conversion in branching degrees of 0.22%, polymerization under a 400 W lamp yields 1.81% of chain branches.

  3. Clinical considerations of the glandular branch of the lacrimal artery.

    PubMed

    Kluckman, Matthew; Fan, Jerry; Balsiger, Heather; Scott, Gabriel; Gest, Thomas

    2015-10-01

    The lacrimal artery is classically described as a branch of the ophthalmic artery supplied by the internal carotid. In this study, 25 orbits were dissected to identify variations in glandular branching and to compare them to previously published accounts. The glandular branching patterns of the lacrimal artery fall into two categories, those that branch (56%) and those that do not branch (44%). We found the medial and lateral glandular branches to be equal in diameter with a divergence of 2.67-40.58 mm proximal to the gland parenchyma. The long glandular branches run alongside the superolateral aspect of the orbit. The lateral branch runs lateral to the lateral rectus muscle. The medial branch runs superomedial to the lateral rectus muscle and lateral to the superior rectus muscle. In relation to the lacrimal gland, the medial branch enters the superior aspect of the gland parenchyma and the lateral branch enters its inferior aspect. The average branch lengths were 17.88 mm (medial) and 13.51 mm (lateral) as measured with a Mitutoyo Absolute 1/100 mm caliper. We could not confirm the existence of a third branch supplying the lacrimal gland, as posited by other authors. The key finding in this study is that the lacrimal gland is predominantly supplied by two significant arterial branches, both of which must be identified during procedures involving the lateral orbit.

  4. Masquerading bundle branch block: a variety of right bundle branch block with left anterior fascicular block.

    PubMed

    Elizari, Marcelo V; Baranchuk, Adrian; Chiale, Pablo A

    2013-01-01

    The so-called 'masquerading' type of right bundle branch block is caused by the simultaneous presence of a high-degree left anterior fascicular block often accompanied with severe left ventricular enlargement and/or fibrotic block in the anterolateral wall of the left ventricle. These conditions tend to reorient the terminal electrical forces of the QRS complex towards the left and upwards, in such a way that the characteristic slurred S wave in lead I becomes smaller or even disappears. In many cases of standard masquerading right bundle branch block, a small Q wave in lead I is present due to the initial forces of the left anterior fascicular block, which are oriented rightwards and inferiorly. However, in some cases, the Q wave in lead I also vanishes, and the mimicking of a left bundle branch block becomes perfect in standard leads. This is commonly associated with an inferior myocardial infarction or severe inferior fibrosis in cardiomyopathies. The typical QRS changes of right bundle branch block may eventually be concealed even in the right precordial leads; under such circumstances, the ECG diagnosis may be mistaken and the right bundle branch block totally missed. The masquerading right bundle branch block carries a poor prognosis, since it always implies the presence of a severe underlying heart disease.

  5. Light Signaling in Bud Outgrowth and Branching in Plants

    PubMed Central

    Leduc, Nathalie; Roman, Hanaé; Barbier, François; Péron, Thomas; Huché-Thélier, Lydie; Lothier, Jérémy; Demotes-Mainard, Sabine; Sakr, Soulaiman

    2014-01-01

    Branching determines the final shape of plants, which influences adaptation, survival and the visual quality of many species. It is an intricate process that includes bud outgrowth and shoot extension, and these in turn respond to environmental cues and light conditions. Light is a powerful environmental factor that impacts multiple processes throughout plant life. The molecular basis of the perception and transduction of the light signal within buds is poorly understood and undoubtedly requires to be further unravelled. This review is based on current knowledge on bud outgrowth-related mechanisms and light-mediated regulation of many physiological processes. It provides an extensive, though not exhaustive, overview of the findings related to this field. In parallel, it points to issues to be addressed in the near future. PMID:27135502

  6. The interplay of matrix metalloproteinases, morphogens and growth factors is necessary for branching of mammary epithelial cells

    SciTech Connect

    Simian, Marina; Hirai, Yohei; Navre, Marc; Werb, Zena; Lochter, Andre; Bissell, Mina J.

    2002-03-06

    The mammary gland develops its adult form by a process referred to as branching morphogenesis. Many factors have been reported to affect this process. We have used cultured primary mammary epithelial organoids and mammary epithelial cell lines in three-dimensional collagen gels to elucidate which growth factors, matrix metalloproteinases (MMPs) and mammary morphogens interact in branching morphogenesis. Branching stimulated by stromal fibroblasts, epidermal growth factor, fibroblast growth factor 7, fibroblast growth factor 2 and hepatocyte growth factor was strongly reduced by inhibitors of MMPs, indicating the requirement of MMPs for three-dimensional growth involved in morphogenesis. Recombinant stromelysin 1/MMP-3 alone was sufficient to drive branching in the absence of growth factors in the organoids. Plasmin also stimulated branching; however, plasmin-dependent branching was abolished by both inhibitors of plasmin and MMPs, suggesting that plasmin activates MMPs. To differentiate between signals for proliferation and morphogenesis, we used a cloned mammary epithelial cell line that lacks epimorphin, an essential mammary morphogen. Both epimorphin and MMPs were required for morphogenesis, but neither was required for epithelial cell proliferation. These results provide direct evidence for a critical role of MMPs in branching in mammary epithelium and suggest that, in addition to epimorphin, MMP activity is a minimum requirement for branching morphogenesis in the mammary gland.

  7. The interplay of matrix metalloproteinases, morphogens and growth factors is necessary for branching of mammary epithelial cells

    SciTech Connect

    Simian, M.; Harail, Y.; Navre, M.; Werb, Z.; Lochter, A.; Bissell, M.J.

    2002-03-06

    The mammary gland develops its adult form by a process referred to as branching morphogenesis. Many factors have been reported to affect this process. We have used cultured primary mammary epithelial organoids and mammary epithelial cell lines in three-dimensional collagen gels to elucidate which growth factors, matrix metalloproteinases (MMPs) and mammary morphogens interact in branching morphogenesis. Branching stimulated by stromal fibroblasts, epidermal growth factor, fibroblast growth factor 7, fibroblast growth factor 2 and hepatocyte growth factor was strongly reduced by inhibitors of MMPs, indicating the requirement of MMPs for three-dimensional growth involved in morphogenesis. Recombinant stromelysin 1/MMP-3 alone was sufficient to drive branching in the absence of growth factors in the organoids. Plasmin also stimulated branching; however, plasmin-dependent branching was abolished by both inhibitors of plasmin and MMPs, suggesting that plasmin activates MMPs. To differentiate between signals for proliferation and morphogenesis, we used a cloned mammary epithelial cell line that lacks epimorphin, an essential mammary morphogen. Both epimorphin and MMPs were required for morphogenesis, but neither was required for epithelial cell proliferation. These results provide direct evidence for a critical role of MMPs in branching in mammary epithelium and suggest that, in addition to epimorphin, MMP activity is a minimum requirement for branching morphogenesis in the mammary gland.

  8. The interplay of matrix metalloproteinases, morphogens and growth factors is necessary for branching of mammary epithelial cells

    PubMed Central

    Simian, Marina; Hirai, Yohei; Navre, Marc; Werb, Zena; Lochter, Andre; Bissell, Mina J.

    2009-01-01

    SUMMARY The mammary gland develops its adult form by a process referred to as branching morphogenesis. Many factors have been reported to affect this process. We have used cultured primary mammary epithelial organoids and mammary epithelial cell lines in three-dimensional collagen gels to elucidate which growth factors, matrix metalloproteinases (MMPs) and mammary morphogens interact in branching morphogenesis. Branching stimulated by stromal fibroblasts, epidermal growth factor, fibroblast growth factor 7, fibroblast growth factor 2 and hepatocyte growth factor was strongly reduced by inhibitors of MMPs, indicating the requirement of MMPs for three-dimensional growth involved in morphogenesis. Recombinant stromelysin 1/MMP3 alone was sufficient to drive branching in the absence of growth factors in the organoids. Plasmin also stimulated branching; however, plasmin-dependent branching was abolished by both inhibitors of plasmin and MMPs, suggesting that plasmin activates MMPs. To differentiate between signals for proliferation and morphogenesis, we used a cloned mammary epithelial cell line that lacks epimorphin, an essential mammary morphogen. Both epimorphin and MMPs were required for morphogenesis, but neither was required for epithelial cell proliferation. These results provide direct evidence for a crucial role of MMPs in branching in mammary epithelium and suggest that, in addition to epimorphin, MMP activity is a minimum requirement for branching morphogenesis in the mammary gland. PMID:11688561

  9. Trapping of branched DNA in microfabricated structures.

    PubMed Central

    Volkmuth, W D; Duke, T; Austin, R H; Cox, E C

    1995-01-01

    We have observed electrostatic trapping of tribranched DNA molecules undergoing electrophoresis in a microfabricated pseudo-two-dimensional array of posts. Trapping occurs in a unique transport regimen in which the electrophoretic mobility is extremely sensitive to polymer topology. The arrest of branched polymers is explained by considering their center-of-mass motion; in certain conformations, owing to the constraints imposed by the obstacles a molecule cannot advance without the center of mass first moving a short distance backwards. The depth of the resulting local potential well can be much greater than the thermal energy so that escape of an immobilized molecule can be extremely slow. We summarize the expected behavior of the mobility as a function of field strength and topology and point out that the microfabricated arrays are highly suitable for detecting an extremely small number of branched molecules in a very large population of linear molecules. Images Fig. 2 PMID:7624337

  10. Morphology of branching trees related to entropy.

    PubMed

    Horsfield, K

    1977-04-01

    Analyses of river systems by geomorphologists have suggested that for minimal entropy production in the movement of water down the river the fall in altitude should be equal in each order of branching of the tributaries. In this paper the same concepts have been applied to the bronchial tree and pulmonary arterial tree, assuming that the energy associated with pressure difference is analogous to that associated with altitude difference in rivers. The morphology of the bronchial tree is such that, given laminar flow or air, the calculated pressure difference across each order is equal. This may indicate that the bronchial tree is designed for minimal entropy production. In the arterial tree, however, this result is not obtained, probably because we do not know how to calculate the pressure drop in blood flowing through a branching system. It is therefore not currently possible, on the basis of this approach, to say whether the pulmonary arterial tree is designed for minimal entropy production or not.

  11. Photovoltaic Program Branch annual report, FY 1989

    SciTech Connect

    Summers, K A

    1990-03-01

    This report summarizes the progress of the Photovoltaic (PV) Program Branch of the Solar Energy Research Institute (SERI) from October 1, 1988, through September 30, 1989. The branch is responsible for managing the subcontracted portion of SERI's PV Advanced Research and Development Project. In fiscal year (FY) 1989, this included nearly 50 subcontracts, with a total annualized funding of approximately $13.1 million. Approximately two-thirds of the subcontracts were with universities, at a total funding of nearly $4 million. The six technical sections of the report cover the main areas of the subcontracted program: Amorphous Silicon Research, Polycrystalline Thin Films, Crystalline Silicon Materials Research, High-Efficiency Concepts, New Ideas, and University Participation. Technical summaries of each of the subcontracted programs provide a discussion of approaches, major accomplishments in FY 1989, and future research directions. Each report will be cataloged individually.

  12. The cytoskeletal and signaling mechanisms of axon collateral branching.

    PubMed

    Gallo, Gianluca

    2011-03-01

    During development, axons are guided to their appropriate targets by a variety of guidance factors. On arriving at their synaptic targets, or while en route, axons form branches. Branches generated de novo from the main axon are termed collateral branches. The generation of axon collateral branches allows individual neurons to make contacts with multiple neurons within a target and with multiple targets. In the adult nervous system, the formation of axon collateral branches is associated with injury and disease states and may contribute to normally occurring plasticity. Collateral branches are initiated by actin filament– based axonal protrusions that subsequently become invaded by microtubules, thereby allowing the branch to mature and continue extending. This article reviews the current knowledge of the cellular mechanisms of the formation of axon collateral branches. The major conclusions of this review are (1) the mechanisms of axon extension and branching are not identical; (2) active suppression of protrusive activity along the axon negatively regulates branching; (3) the earliest steps in the formation of axon branches involve focal activation of signaling pathways within axons, which in turn drive the formation of actin-based protrusions; and (4) regulation of the microtubule array by microtubule-associated and severing proteins underlies the development of branches. Linking the activation of signaling pathways to specific proteins that directly regulate the axonal cytoskeleton underlying the formation of collateral branches remains a frontier in the field.

  13. [Geometry and algebra of branches of the middle cerebral artery].

    PubMed

    Blinkov, S M

    1986-01-01

    A classification of the cortical branches of the middle cerebral artery (MCA) is suggested by means of which each branch in any hemisphere can be qualified and identified in any variant of MCA branching. The principle of the classification consists in grouping the branches into arteries and trunks of the second, third, etc. order. Branches supplying blood to a certain sector of the lateral surface of the hemisphere are designated arteries. Their number and zone of branching are constant. Branches giving rise to 2 and more arteries are named trunks. Branching of the trunks, the number of trunks of the second, third, etc. order, and the site and type of origin of the arteries are extremely variable. Each trunk can be designated by a formula stating its order and the name of the artery supplied by this trunk. The arrangement of the MCA branches on the surface of the gyri and deep in the sulci, represented on the map of the lateral surface of the hemisphere, is designated conditionally as geometry of MCA branches. The order of branching of the trunks and the type of origin of the arteries, represented on abstract maps of the lateral surface of the hemisphere, are designated conditionally as algebra of the MCA branches. The variability of the geometry and algebra of the MCA branches must be taken into consideration in operations for extra-intracranial microanastomosis and in endovasal intervention on the MCA.

  14. Polyatomic ions, branching ratios and hot molecules

    NASA Astrophysics Data System (ADS)

    Mitchell, J. Brian A.

    2015-01-01

    A discussion is given of the reason for the sharp fall-off observed in Dissociative Recombination (DR) cross sections above about 0.1 eV and of the need for accurate branching ratios being used in complex models of molecular ion chemistry. New measurements from TSR have shown that stored ions are not as cold as they were once thought to be and a new experiment facility is presented.

  15. Expression of Escherichia coli branching enzyme in tubers of amylose-free transgenic potato leads to an increased branching degree of the amylopectin.

    PubMed

    Kortstee, A J; Vermeesch, A M; de Vries, B J; Jacobsen, E; Visser, R G

    1996-07-01

    In order to increase the branching degree of potato tuber starch, the gene encoding branching enzyme (glgB) of Escherichia coli was expressed in the amylose-free potato mutant. The E. coli glgB was cloned in the binary vector pBIN19 under the transcriptional control of the potato Granule Bound Starch Synthase (GBSS) promoter and transitpeptide sequence. The E. coli glgB was cloned behind the two N-terminal amino acids of the GBSS mature protein, creating a chimeric protein. Transgenic plants were obtained which expressed the E. coli branching enzyme as was shown by the presence of mRNA and protein in the tubers. Correctly processed protein was found both in the soluble and starch granule bound protein fraction. Analysis of the starch showed an increase in the branching degree (DE) of up to 25% more branchpoints. The increase in the number of branchpoints was due to the presence of more short chains, with a degree of polymerization (DP) of 16 glucose-residues or less in the amylopectin. Changes in other characteristics of the starch, such as average chain length (CL) and lambda max, indicated a more branched structure for starch of transformed plants as well.

  16. Overview of Glenn Mechanical Components Branch Research

    NASA Astrophysics Data System (ADS)

    Zakrajsek, James

    2002-09-01

    Mr. James Zakrajsek, chief of the Mechanical Components Branch, gave an overview of research conducted by the branch. Branch members perform basic research on mechanical components and systems, including gears and bearings, turbine seals, structural and thermal barrier seals, and space mechanisms. The research is focused on propulsion systems for present and advanced aerospace vehicles. For rotorcraft and conventional aircraft, we conduct research to develop technology needed to enable the design of low noise, ultra safe geared drive systems. We develop and validate analytical models for gear crack propagation, gear dynamics and noise, gear diagnostics, bearing dynamics, and thermal analyses of gear systems using experimental data from various component test rigs. In seal research we develop and test advanced turbine seal concepts to increase efficiency and durability of turbine engines. We perform experimental and analytical research to develop advanced thermal barrier seals and structural seals for current and next generation space vehicles. Our space mechanisms research involves fundamental investigation of lubricants, materials, components and mechanisms for deep space and planetary environments.

  17. Overview of Glenn Mechanical Components Branch Research

    NASA Technical Reports Server (NTRS)

    Zakrajsek, James

    2002-01-01

    Mr. James Zakrajsek, chief of the Mechanical Components Branch, gave an overview of research conducted by the branch. Branch members perform basic research on mechanical components and systems, including gears and bearings, turbine seals, structural and thermal barrier seals, and space mechanisms. The research is focused on propulsion systems for present and advanced aerospace vehicles. For rotorcraft and conventional aircraft, we conduct research to develop technology needed to enable the design of low noise, ultra safe geared drive systems. We develop and validate analytical models for gear crack propagation, gear dynamics and noise, gear diagnostics, bearing dynamics, and thermal analyses of gear systems using experimental data from various component test rigs. In seal research we develop and test advanced turbine seal concepts to increase efficiency and durability of turbine engines. We perform experimental and analytical research to develop advanced thermal barrier seals and structural seals for current and next generation space vehicles. Our space mechanisms research involves fundamental investigation of lubricants, materials, components and mechanisms for deep space and planetary environments.

  18. Cold versus hot fusion deuterium branching ratios

    SciTech Connect

    Fox, H.; Bass, R.

    1995-12-31

    A major source of misunderstanding of the nature of cold nuclear fusion has been the expectation that the deuterium branching ratios occurring within a palladium lattice would be consistent with the gas-plasma branching ratios. This misunderstanding has led to the concept of the dead graduate student, the 1989`s feverish but fruitless search for neutron emissions from cold fusion reactors, and the follow-on condemnation of the new science of cold fusion. The experimental facts are that in a properly loaded palladium lattice, the deuterium fusion produces neutrons at little above background, a greatly less-than-expected production of tritium (the tritium desert), and substantially more helium-4 than is observed in hot plasma physics. The experimental evidence is now compelling (800 reports of success from 30 countries) that cold nuclear fusion is a reality, that the branching ratios are unexpected, and that a new science is struggling to be recognized. Commercialization of some types of cold fusion devices has already begun.

  19. Measurement of tau lepton branching fractions

    SciTech Connect

    Nicol, Neil Allen

    1993-09-30

    We present τ- lepton branching fraction measurements based on data from the TPC/Two-Gamma detector at PEP. Using a sample of τ- → vτK-π+π- events, we examine the resonance structure of the K-π+π- system and obtain the first measurements of branching fractions for τ- → vτK$-\\atop{1}$(1270) and τ- → vτK$-\\atop{1}$(1400). We also describe a complete set of branching fraction measurements in which all the decays of the τ- lepton are separated into classes defined by the identities of the charged particles and an estimate of the number of neutrals. This is the first such global measurement with decay classes defined by the four possible charged particle species, e, μ, π, and K.

  20. Fabrication and characterization of branched carbon nanostructures

    PubMed Central

    Nemoto, Yoshihiro; Guo, Hongxuan; Ariga, Katsuhiko; Hill, Jonathan P

    2016-01-01

    Summary Carbon nanotubes (CNTs) have atomically smooth surfaces and tend not to form covalent bonds with composite matrix materials. Thus, it is the magnitude of the CNT/fiber interfacial strength that limits the amount of nanomechanical interlocking when using conventional CNTs to improve the structural behavior of composite materials through reinforcement. This arises from two well-known, long standing problems in this research field: (a) inhomogeneous dispersion of the filler, which can lead to aggregation and (b) insufficient reinforcement arising from bonding interactions between the filler and the matrix. These dispersion and reinforcement issues could be addressed by using branched multiwalled carbon nanotubes (b-MWCNTs) as it is known that branched fibers can greatly enhance interfacial bonding and dispersability. Therefore, the use of b-MWCNTs would lead to improved mechanical performance and, in the case of conductive composites, improved electrical performance if the CNT filler was better dispersed and connected. This will provide major benefits to the existing commercial application of CNT-reinforced composites in electrostatic discharge materials (ESD): There would be also potential usage for energy conversion, e.g., in supercapacitors, solar cells and Li-ion batteries. However, the limited availability of b-MWCNTs has, to date, restricted their use in such technological applications. Herein, we report an inexpensive and simple method to fabricate large amounts of branched-MWCNTs, which opens the door to a multitude of possible applications. PMID:27826499

  1. Fabrication and characterization of branched carbon nanostructures.

    PubMed

    Malik, Sharali; Nemoto, Yoshihiro; Guo, Hongxuan; Ariga, Katsuhiko; Hill, Jonathan P

    2016-01-01

    Carbon nanotubes (CNTs) have atomically smooth surfaces and tend not to form covalent bonds with composite matrix materials. Thus, it is the magnitude of the CNT/fiber interfacial strength that limits the amount of nanomechanical interlocking when using conventional CNTs to improve the structural behavior of composite materials through reinforcement. This arises from two well-known, long standing problems in this research field: (a) inhomogeneous dispersion of the filler, which can lead to aggregation and (b) insufficient reinforcement arising from bonding interactions between the filler and the matrix. These dispersion and reinforcement issues could be addressed by using branched multiwalled carbon nanotubes (b-MWCNTs) as it is known that branched fibers can greatly enhance interfacial bonding and dispersability. Therefore, the use of b-MWCNTs would lead to improved mechanical performance and, in the case of conductive composites, improved electrical performance if the CNT filler was better dispersed and connected. This will provide major benefits to the existing commercial application of CNT-reinforced composites in electrostatic discharge materials (ESD): There would be also potential usage for energy conversion, e.g., in supercapacitors, solar cells and Li-ion batteries. However, the limited availability of b-MWCNTs has, to date, restricted their use in such technological applications. Herein, we report an inexpensive and simple method to fabricate large amounts of branched-MWCNTs, which opens the door to a multitude of possible applications.

  2. The root of branching river networks.

    PubMed

    Perron, J Taylor; Richardson, Paul W; Ferrier, Ken L; Lapôtre, Mathieu

    2012-12-06

    Branching river networks are one of the most widespread and recognizable features of Earth's landscapes and have also been discovered elsewhere in the Solar System. But the mechanisms that create these patterns and control their spatial scales are poorly understood. Theories based on probability or optimality have proven useful, but do not explain how river networks develop over time through erosion and sediment transport. Here we show that branching at the uppermost reaches of river networks is rooted in two coupled instabilities: first, valleys widen at the expense of their smaller neighbours, and second, side slopes of the widening valleys become susceptible to channel incision. Each instability occurs at a critical ratio of the characteristic timescales for soil transport and channel incision. Measurements from two field sites demonstrate that our theory correctly predicts the size of the smallest valleys with tributaries. We also show that the dominant control on the scale of landscape dissection in these sites is the strength of channel incision, which correlates with aridity and rock weakness, rather than the strength of soil transport. These results imply that the fine-scale structure of branching river networks is an organized signature of erosional mechanics, not a consequence of random topology.

  3. Indexes system of technological condition assessment of economic branches

    NASA Astrophysics Data System (ADS)

    Chuvashova, M. N.; Avramchikova, N. T.; Antamoshkin, A. N.

    2015-10-01

    The increased level of innovative production process, connected with the current trends, points out the necessity of economic diversification of the whole national economy as well as regional economies in order to increase competitiveness and stable development. Russian regional economies are characterized with local directive of development and innovative processes have evident local vector. Intensive development of Siberian regional economies, which depends on oil and mining industries, considerably falls behind the world indicators according to the GRP output per head. To improve the quality of economic space the authors have suggested a new scientific approach, which allows qualitative assessment inside the economic space of resource-based regions, based on principles of high technological modes development inside economic branches taking into account density, regular enterprise distribution and connectivity of commercial organizations as well as secures innovative development of regional economy and its competitiveness. In this context it is necessary to develop a modern system of indexes, characterizing the structure of economic branches in accordance with present technological modes and at the same time the dynamics of appropriate structural shifts in regional economies of this type.

  4. Colloidal nanocrystal heterostructures with linear and branched topology.

    PubMed

    Milliron, Delia J; Hughes, Steven M; Cui, Yi; Manna, Liberato; Li, Jingbo; Wang, Lin-Wang; Alivisatos, A Paul

    2004-07-08

    The development of colloidal quantum dots has led to practical applications of quantum confinement, such as in solution-processed solar cells, lasers and as biological labels. Further scientific and technological advances should be achievable if these colloidal quantum systems could be electronically coupled in a general way. For example, this was the case when it became possible to couple solid-state embedded quantum dots into quantum dot molecules. Similarly, the preparation of nanowires with linear alternating compositions--another form of coupled quantum dots--has led to the rapid development of single-nanowire light-emitting diodes and single-electron transistors. Current strategies to connect colloidal quantum dots use organic coupling agents, which suffer from limited control over coupling parameters and over the geometry and complexity of assemblies. Here we demonstrate a general approach for fabricating inorganically coupled colloidal quantum dots and rods, connected epitaxially at branched and linear junctions within single nanocrystals. We achieve control over branching and composition throughout the growth of nanocrystal heterostructures to independently tune the properties of each component and the nature of their interactions. Distinct dots and rods are coupled through potential barriers of tuneable height and width, and arranged in three-dimensional space at well-defined angles and distances. Such control allows investigation of potential applications ranging from quantum information processing to artificial photosynthesis.

  5. Evidence that dendritic mitochondria negatively regulate dendritic branching in pyramidal neurons in the neocortex.

    PubMed

    Kimura, Toshiya; Murakami, Fujio

    2014-05-14

    The precise branching patterns of dendritic arbors have a profound impact on information processing in individual neurons and the brain. These patterns are established by positive and negative regulation of the dendritic branching. Although the mechanisms for positive regulation have been extensively investigated, little is known about those for negative regulation. Here, we present evidence that mitochondria located in developing dendrites are involved in the negative regulation of dendritic branching. We visualized mitochondria in pyramidal neurons of the mouse neocortex during dendritic morphogenesis using in utero electroporation of a mitochondria-targeted fluorescent construct. We altered the mitochondrial distribution in vivo by overexpressing Mfn1, a mitochondrial shaping protein, or the Miro-binding domain of TRAK2 (TRAK2-MBD), a truncated form of a motor-adaptor protein. We found that dendritic mitochondria were preferentially targeted to the proximal portion of dendrites only during dendritic morphogenesis. Overexpression of Mfn1 or TRAK2-MBD depleted mitochondria from the dendrites, an effect that was accompanied by increased branching of the proximal portion of the dendrites. This dendritic abnormality cannot be accounted for by changes in the distribution of membrane trafficking organelles since the overexpression of Mfn1 did not alter the distributions of the endoplasmic reticulum, Golgi, or endosomes. Additionally, neither did these constructs impair neuronal viability or mitochondrial function. Therefore, our results suggest that dendritic mitochondria play a critical role in the establishment of the precise branching pattern of dendritic arbors by negatively affecting dendritic branching.

  6. A computational model of dendrite elongation and branching based on MAP2 phosphorylation.

    PubMed

    Hely, T A; Graham, B; Ooyen, A V

    2001-06-07

    We introduce a new computational model of dendritic development in neurons. In contrast to previous models, our model explicitly includes cellular mechanisms involved in dendritic development. It is based on recent experimental data which indicates that the phosphorylation state of microtubule-associated protein 2 (MAP2) may play a key role in controlling dendritic elongation and branching (Audesirk et al., 1997). Dephosphorylated MAP2 favours elongation by promoting microtubule polymerization and bundling, whilst branching is more likely to occur when MAP2 is phosphorylated and microtubules are spaced apart. In the model, the rate of elongation and branching is directly determined by the ratio of phosphorylated to dephosphorylated MAP2. This is regulated by calmodulin-dependent protein kinase II (CaMKII) and calcineurin, which are both dependent on the intracellular calcium concentration. Results from computer simulations of the model suggest that the wide variety of branching patterns observed among different cell types may be generated by the same underlying mechanisms and that elongation and branching are not necessarily independent processes. The model predicts how the branching pattern will change following manipulations with calcium, CaMKII and MAP2 phosphorylation.

  7. Auxin transport in the evolution of branching forms.

    PubMed

    Harrison, C Jill

    2017-07-01

    Contents 545 I. 545 II. 546 III. 546 IV. 548 V. 548 VI. 549 VII. 549 Acknowledgements 549 References 549 SUMMARY: Branching is one of the most striking aspects of land plant architecture, affecting resource acquisition and yield. Polar auxin transport by PIN proteins is a primary determinant of flowering plant branching patterns regulating both branch initiation and branch outgrowth. Several lines of experimental evidence suggest that PIN-mediated polar auxin transport is a conserved regulator of branching in vascular plant sporophytes. However, the mechanisms of branching and auxin transport and relationships between the two are not well known outside the flowering plants, and the paradigm for PIN-regulated branching in flowering plants does not fit bryophyte gametophytes. The evidence reviewed here suggests that divergent auxin transport routes contributed to the diversification of branching forms in distinct land plant lineages. © 2016 The Authors. New Phytologist © 2016 New Phytologist Trust.

  8. Hilbert Series and Mixed Branches of T [SU( N )] theories

    NASA Astrophysics Data System (ADS)

    Carta, Federico; Hayashi, Hirotaka

    2017-02-01

    We consider mixed branches of 3 d N = 4 T [SU( N )] theory. We compute the Hilbert series of the Coulomb branch part of the mixed branch from a restriction rule acting on the Hilbert series of the full Coulomb branch that will truncate the magnetic charge summation only to the subset of BPS dressed monopole operators that arise in the Coulomb branch sublocus where the mixed branch stems. This restriction can be understood directly from the type IIB brane picture by a relation between the magnetic charges of the monopoles and brane position moduli. We also apply the restriction rule to the Higgs branch part of a given mixed branch by exploiting 3d mirror symmetry. Both ccases show complete agreement with the results calculated by different methods.

  9. Detail view of bronze door. Note oak branches with acorns ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Detail view of bronze door. Note oak branches with acorns in the left panels and olive branches with olives in right. - Flanders Field American Cemetery & Memorial, Chapel, Wortegemseweg 117, Waregem, West Flanders (Belgium)

  10. West Branch Pennsylvania Canal, Lock No. 34 Lock Keeper's House, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    West Branch Pennsylvania Canal, Lock No. 34 Lock Keeper's House, South of State Route 664 along North bank of West Branch of Susquehanna River, 2,000 feet East of Jay Street Bridge, Lock Haven, Clinton County, PA

  11. Trees and streams: The efficiency of branching patterns

    USGS Publications Warehouse

    Leopold, Luna Bergere

    1971-01-01

    Extending the analysis of branching patterns of the drainage net of rivers, originated by Horton, the relation of average numbers and lengths of tree branches to size of branch was investigated. Size of branch was defined by branch order, or its position in the hierarchy of tributaries. It was found that, as in river drainage nets, there is a definite logarithmic relation between branch order and lengths and numbers. This definite relation is quantitatively comparable, within limits, among river networks, tree branching systems, and several random-walk models in both two and three dimensions. Such a relation appears to be the most probable under the applicable constraints. Moreover the most probable arrangement appears to minimize the total length of all stems in the branching system within other constraints and so, to that extent, achieves a certain efficiency.

  12. Asymmetric Branching in Biological Resource Distribution Networks

    NASA Astrophysics Data System (ADS)

    Brummer, Alexander Byers

    There is a remarkable relationship between an organism's metabolic rate (resting power consumption) and the organism's mass. It may be a universal law of nature that an organism's resting metabolic rate is proportional to its mass to the power of 3/4. This relationship, known as Kleiber's Law, appears to be valid for both plants and animals. This law is important because it implies that larger organisms are more efficient than smaller organisms, and knowledge regarding metabolic rates are essential to a multitude of other fields in ecology and biology. This includes modeling the interactions of many species across multiple trophic levels, distributions of species abundances across large spatial landscapes, and even medical diagnostics for respiratory and cardiovascular pathologies. Previous models of vascular networks that seek to identify the origin of metabolic scaling have all been based on the unrealistic assumption of perfectly symmetric branching. In this dissertation I will present a theory of asymmetric branching in self-similar vascular networks (published by Brummer et al. in [9]). The theory shows that there can exist a suite of vascular forms that result in the often observed 3/4 metabolic scaling exponent of Kleiber's Law. Furthermore, the theory makes predictions regarding major morphological features related to vascular branching patterns and their relationships to metabolic scaling. These predictions are suggestive of evolutionary convergence in vascular branching. To test these predictions, I will present an analysis of real mammalian and plant vascular data that shows: (i) broad patterns in vascular networks across entire animal kingdoms and (ii) within these patterns, plant and mammalian vascular networks can be uniquely distinguished from one another (publication in preparation by Brummer et al.). I will also present results from a computational study in support of point (i). Namely, that asymmetric branching may be the optimal strategy to

  13. An information-theoretic look at branch-prediction

    SciTech Connect

    Ponder, C.G. ); Shebanow, M.C. )

    1990-09-11

    Accurate branch-prediction is necessary to utilize deeply pipelined and Very Long Instruction-Word (VLIW) architectures. For a set of program traces we show the upper limits on branch predictability, and hence machine utilization, for important classes of branch-predictors using static (compiletime) and dynamic (runtime) program information. A set of optimal superpredictors'' is derived from these program traces. These optimal predictors compare favorably with other proposed methods of branch-prediction. 3 refs., 5 figs., 12 tabs.

  14. Structural Dynamics Branch research and accomplishments for FY 1990

    NASA Technical Reports Server (NTRS)

    1991-01-01

    Presented here is a collection of FY 1990 research highlights from the Structural Dynamics Branch at the NASA Lewis Research Center. Highlights are from the branch's major work areas: aeroelasticity, vibration control, dynamic systems, and computational structural methods. A listing is given of FY 1990 branch publications.

  15. Structural dynamics branch research and accomplishments for fiscal year 1987

    NASA Technical Reports Server (NTRS)

    1988-01-01

    This publication contains a collection of fiscal year 1987 research highlights from the Structural Dynamics Branch at NASA Lewis Research Center. Highlights from the branch's four major work areas, Aeroelasticity, Vibration Control, Dynamic Systems, and Computational Structural Methods, are included in the report as well as a complete listing of the FY87 branch publications.

  16. 46 CFR 111.75-5 - Lighting branch circuits.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 4 2013-10-01 2013-10-01 false Lighting branch circuits. 111.75-5 Section 111.75-5...-GENERAL REQUIREMENTS Lighting Circuits and Protection § 111.75-5 Lighting branch circuits. (a) Loads. A lighting distribution panel must not supply branch circuits rated at over 30 amperes. (b) Connected Load...

  17. 30 CFR 57.12084 - Branch circuit disconnecting devices.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Branch circuit disconnecting devices. 57.12084... Electricity Underground Only § 57.12084 Branch circuit disconnecting devices. Disconnecting switches that can be opened safely under load shall be provided underground at all branch circuits extending from...

  18. 30 CFR 57.12084 - Branch circuit disconnecting devices.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Branch circuit disconnecting devices. 57.12084... Electricity Underground Only § 57.12084 Branch circuit disconnecting devices. Disconnecting switches that can be opened safely under load shall be provided underground at all branch circuits extending from...

  19. 30 CFR 57.12084 - Branch circuit disconnecting devices.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Branch circuit disconnecting devices. 57.12084... Electricity Underground Only § 57.12084 Branch circuit disconnecting devices. Disconnecting switches that can be opened safely under load shall be provided underground at all branch circuits extending from...

  20. 24 CFR 3280.805 - Branch circuits required.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 24 Housing and Urban Development 5 2010-04-01 2010-04-01 false Branch circuits required. 3280.805... Branch circuits required. (a) The number of branch circuits required shall be determined in accordance... or 20 ampere lighting area circuits. e.g. = number of 15 or 20 ampere circuits. (2) Small appliances...

  1. 46 CFR 111.75-5 - Lighting branch circuits.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 4 2012-10-01 2012-10-01 false Lighting branch circuits. 111.75-5 Section 111.75-5...-GENERAL REQUIREMENTS Lighting Circuits and Protection § 111.75-5 Lighting branch circuits. (a) Loads. A lighting distribution panel must not supply branch circuits rated at over 30 amperes. (b) Connected Load...

  2. 46 CFR 111.75-5 - Lighting branch circuits.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 4 2014-10-01 2014-10-01 false Lighting branch circuits. 111.75-5 Section 111.75-5...-GENERAL REQUIREMENTS Lighting Circuits and Protection § 111.75-5 Lighting branch circuits. (a) Loads. A lighting distribution panel must not supply branch circuits rated at over 30 amperes. (b) Connected Load...

  3. 46 CFR 111.75-5 - Lighting branch circuits.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 4 2011-10-01 2011-10-01 false Lighting branch circuits. 111.75-5 Section 111.75-5...-GENERAL REQUIREMENTS Lighting Circuits and Protection § 111.75-5 Lighting branch circuits. (a) Loads. A lighting distribution panel must not supply branch circuits rated at over 30 amperes. (b) Connected Load...

  4. 46 CFR 111.75-5 - Lighting branch circuits.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Lighting branch circuits. 111.75-5 Section 111.75-5...-GENERAL REQUIREMENTS Lighting Circuits and Protection § 111.75-5 Lighting branch circuits. (a) Loads. A lighting distribution panel must not supply branch circuits rated at over 30 amperes. (b) Connected Load...

  5. 30 CFR 57.12084 - Branch circuit disconnecting devices.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Branch circuit disconnecting devices. 57.12084... Electricity Underground Only § 57.12084 Branch circuit disconnecting devices. Disconnecting switches that can be opened safely under load shall be provided underground at all branch circuits extending from...

  6. 30 CFR 57.12084 - Branch circuit disconnecting devices.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Branch circuit disconnecting devices. 57.12084... Electricity Underground Only § 57.12084 Branch circuit disconnecting devices. Disconnecting switches that can be opened safely under load shall be provided underground at all branch circuits extending from...

  7. 24 CFR 3280.805 - Branch circuits required.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 24 Housing and Urban Development 5 2011-04-01 2011-04-01 false Branch circuits required. 3280.805... Branch circuits required. (a) The number of branch circuits required shall be determined in accordance... or 20 ampere lighting area circuits. e.g. = number of 15 or 20 ampere circuits. (2) Small appliances...

  8. 24 CFR 3280.805 - Branch circuits required.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 24 Housing and Urban Development 5 2014-04-01 2014-04-01 false Branch circuits required. 3280.805... Branch circuits required. Link to an amendment published at 78 FR 73991, Dec. 9, 2013. (a) The number of branch circuits required shall be determined in accordance with the following: (1) Lighting, based on 3...

  9. 40 CFR 721.3627 - Branched synthetic fatty acid.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Branched synthetic fatty acid. 721... Substances § 721.3627 Branched synthetic fatty acid. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as a branched synthetic fatty acid...

  10. 40 CFR 721.3627 - Branched synthetic fatty acid.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Branched synthetic fatty acid. 721... Substances § 721.3627 Branched synthetic fatty acid. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as a branched synthetic fatty acid...

  11. 40 CFR 721.3627 - Branched synthetic fatty acid.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Branched synthetic fatty acid. 721... Substances § 721.3627 Branched synthetic fatty acid. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as a branched synthetic fatty acid...

  12. 26 CFR 1.884-1 - Branch profits tax.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 26 Internal Revenue 9 2014-04-01 2014-04-01 false Branch profits tax. 1.884-1 Section 1.884-1 Internal Revenue INTERNAL REVENUE SERVICE, DEPARTMENT OF THE TREASURY (CONTINUED) INCOME TAX (CONTINUED) INCOME TAXES (CONTINUED) Foreign Corporations § 1.884-1 Branch profits tax. (a) General rule. A foreign corporation shall be liable for a branch...

  13. 26 CFR 1.884-1 - Branch profits tax.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

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    Code of Federal Regulations, 2012 CFR

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    Code of Federal Regulations, 2013 CFR

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  16. Structural dynamics branch research and accomplishments to FY 1992

    NASA Technical Reports Server (NTRS)

    Lawrence, Charles

    1992-01-01

    This publication contains a collection of fiscal year 1992 research highlights from the Structural Dynamics Branch at NASA LeRC. Highlights from the branch's major work areas--Aeroelasticity, Vibration Control, Dynamic Systems, and Computational Structural Methods are included in the report as well as a listing of the fiscal year 1992 branch publications.

  17. 40 CFR 721.10094 - Decene, branched and linear.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

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  18. 40 CFR 721.10094 - Decene, branched and linear.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

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    Code of Federal Regulations, 2013 CFR

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    Code of Federal Regulations, 2010 CFR

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