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. 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

  3. Lyapunov Exponents for Branching Processes in a Random Environment: The Effect of Information

    NASA Astrophysics Data System (ADS)

    Hautphenne, Sophie; Latouche, Guy

    2016-04-01

    We consider multitype branching processes evolving in a Markovian random environment. To determine whether or not the branching process becomes extinct almost surely is akin to computing the maximal Lyapunov exponent of a sequence of random matrices, which is a notoriously difficult problem. We define Markov chains associated to the branching process, and we construct bounds for the Lyapunov exponent. The bounds are obtained by adding or by removing information: to add information results in a lower bound, to remove information results in an upper bound, and we show that adding less information improves the lower bound. We give a few illustrative examples and we observe that the upper bound is generally more accurate than the lower bounds.

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  5. 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

  6. Detection of branching points in noisy processes

    NASA Astrophysics Data System (ADS)

    Beer, Michael; Liebscher, Martin

    2010-03-01

    Processes in engineering mechanics often contain branching points at which the system can follow different physical paths. In this paper a method for the detection of these branching points is proposed for processes that are affected by noise. It is assumed that a bundle of process records are available from numerical simulations or from experiments, and branching points are concealed by the noise of the process. The bundle of process records is then evaluated at a series of discrete values of the independent process coordinates. At each discrete point of the process, the associated point set of process values is investigated with the aid of cluster analysis. The detected branching points are verified with a recursive algorithm. The revealed information about the branching points can be used to identify the physical and mechanical background for the branching. This helps to better understand a mechanical system and to design it optimal for a specific purpose. The proposed method is demonstrated by means of both a numerical example and a practical example of a crashworthiness investigation.

  7. Discrete time spatial models arising in genetics, evolutionary game theory, and branching processes.

    PubMed

    Radcliffe, J; Rass, L

    1997-03-01

    A saddle point method is used to obtain the speed of first spread of new genotypes in genetic models and of new strategies in game theoretic models. It is also used to obtain the speed of the forward tail of the distribution of farthest spread for branching process models. The technique is applicable to a wide range of models. They include multiple allele and sex-linked models in genetics, multistrategy and bimatrix evolutionary games, and multitype and demographic branching processes. The speed of propagation has been obtained for genetics models (in simple cases only) by Weinberger and Lui, using exact analytical methods. The exact results were obtained only for two-allele, single-locus genetic models. The saddle point method agrees in these very simple cases with the results obtained by using the exact analytic methods. Of course, it can also be used in much more general situations far less tractable to exact analysis. The connection between genetic and game theoretic models is also briefly considered, as is the extent to which the exact analytic methods yield results for simple models in game theory. PMID:9046771

  8. 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.

  9. 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)

  10. Branching process in a stochastic extremal model

    NASA Astrophysics Data System (ADS)

    Manna, S. S.

    2009-08-01

    We considered a stochastic version of the Bak-Sneppen model (SBSM) of ecological evolution where the number M of sites mutated in a mutation event is restricted to only two. Here the mutation zone consists of only one site and this site is randomly selected from the neighboring sites at every mutation event in an annealed fashion. The critical behavior of the SBSM is found to be the same as the BS model in dimensions d=1 and 2. However on the scale-free graphs the critical fitness value is nonzero even in the thermodynamic limit but the critical behavior is mean-field like. Finally ⟨M⟩ has been made even smaller than two by probabilistically updating the mutation zone, which also shows the original BS model behavior. We conjecture that a SBSM on any arbitrary graph with any small branching factor greater than unity will lead to a self-organized critical state.

  11. Branching process in a stochastic extremal model.

    PubMed

    Manna, S S

    2009-08-01

    We considered a stochastic version of the Bak-Sneppen model (SBSM) of ecological evolution where the number M of sites mutated in a mutation event is restricted to only two. Here the mutation zone consists of only one site and this site is randomly selected from the neighboring sites at every mutation event in an annealed fashion. The critical behavior of the SBSM is found to be the same as the BS model in dimensions d=1 and 2. However on the scale-free graphs the critical fitness value is nonzero even in the thermodynamic limit but the critical behavior is mean-field like. Finally M has been made even smaller than two by probabilistically updating the mutation zone, which also shows the original BS model behavior. We conjecture that a SBSM on any arbitrary graph with any small branching factor greater than unity will lead to a self-organized critical state. PMID:19792102

  12. Processability improvement of polyolefins through radiation-induced branching

    NASA Astrophysics Data System (ADS)

    Cheng, Song; Phillips, Ed; Parks, Lewis

    2010-03-01

    Radiation-induced long-chain branching for the purpose of improving melt strength and hence the processability of polypropylene (PP) and polyethylene (PE) is reviewed. Long-chain branching without significant gel content can be created by low dose irradiation of PP or PE under different atmospheres, with or without multifunctional branching promoters. The creation of long-chain branching generally leads to improvement of melt strength, which in turn may be translated into processability improvement for specific applications in which melt strength plays an important role. In this paper, the changes of the melt flow rate and the melt strength of the irradiated polymer and the relationship between long-chain branching and melt strength are reviewed. The effects of the atmosphere and the branching promoter on long-chain branching vs. degradation are discussed. The benefits of improved melt strength on the processability, e.g., sag resistance and strain hardening, are illustrated. The implications on practical polymer processing applications such as foams and films are also discussed.

  13. 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.

  14. PROJECT LISTING - CLEAN PROCESSES BRANCH (SUSTAINABLE TECHNOLOGY DIVISION, NRMRL)

    EPA Science Inventory

    This list of projects for the Clean Processes Branch (CPB)of NRMRL's Sustainable Technology Division covers CPB projects in the areas of metal finishing and electronics pollution prevention; green engineering for chemical synthesis; solvent and coatings alternatives; separations ...

  15. Stochastic Equation of Fragmentation and Branching Processes Related to Avalanches

    NASA Astrophysics Data System (ADS)

    Beznea, Lucian; Deaconu, Madalina; Lupaşcu, Oana

    2016-02-01

    We give a stochastic model for the fragmentation phase of an avalanche. We construct a fragmentation-branching process related to the avalanches, on the set of all fragmentation sizes introduced by Bertoin. A fractal property of this process is emphasized. We also establish a specific stochastic differential equation of fragmentation. It turns out that specific branching Markov processes on finite configurations of particles with sizes bigger than a strictly positive threshold are convenient for describing the continuous time evolution of the number of the resulting fragments. The results are obtained by combining analytic and probabilistic potential theoretical tools.

  16. 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)

  17. 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…

  18. 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.

  19. 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.

  20. 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

  1. 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.

  2. Generalized Low-Temperature Fabrication of Scalable Multi-Type Two-Dimensional Nanosheets with a Green Soft Template.

    PubMed

    Wang, Lanfang; Song, Chuang; Shi, Yi; Dang, Liyun; Jin, Ying; Jiang, Hong; Lu, Qingyi; Gao, Feng

    2016-04-11

    Two-dimensional nanosheets with high specific surface areas and fascinating physical and chemical properties have attracted tremendous interests because of their promising potentials in both fundamental research and practical applications. However, the problem of developing a universal strategy with a facile and cost-effective synthesis process for multi-type ultrathin 2 D nanostructures remains unresolved. Herein, we report a generalized low-temperature fabrication of scalable multi-type 2 D nanosheets including metal hydroxides (such as Ni(OH)2, Co(OH)2, Cd(OH)2, and Mg(OH)2), metal oxides (such as ZnO and Mn3O4), and layered mixed transition-metal hydroxides (Ni-Co LDH, Ni-Fe LDH, Co-Fe LDH, and Ni-Co-Fe layered ternary hydroxides) through the rational employment of a green soft-template. The synthesized crystalline inorganic nanosheets possess confined thickness, resulting in ultrahigh surface atom ratios and chemically reactive facets. Upon evaluation as electrode materials for pseudocapacitors, the Ni-Co LDH nanosheets exhibit a high specific capacitance of 1087 F g(-1) at a current density of 1 A g(-1), and excellent stability, with 103% retention after 500 cycles. This strategy is facile and scalable for the production of high-quality ultrathin crystalline inorganic nanosheets, with the possibility of extension to the preparation of other complex nanosheets. PMID:26946433

  3. 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.

  4. Mathematical modeling in biological populations through branching processes. Application to salmonid populations.

    PubMed

    Molina, Manuel; Mota, Manuel; Ramos, Alfonso

    2015-01-01

    This work deals with mathematical modeling through branching processes. We consider sexually reproducing animal populations where, in each generation, the number of progenitor couples is determined in a non-predictable environment. By using a class of two-sex branching processes, we describe their demographic dynamics and provide several probabilistic and inferential contributions. They include results about the extinction of the population and the estimation of the offspring distribution and its main moments. We also present an application to salmonid populations. PMID:24526259

  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. 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. PMID:25933659

  7. Punctuated Equilibrium Behavior and Zipf's Law in the Stochastic Branching Process Model of Phylogeny

    NASA Astrophysics Data System (ADS)

    Matsumoto, T.; Aizawa, Y.

    1999-11-01

    A stochastic branching process model of phylogeny with niche space and interactions among species is considered. For an intermediate interaction range, the time series of diversity has long periods of stasis divided by periods of rapid increase. The concept of monophyletic size is introduced, and it is shown that the size distribution obeys Zipf's law.

  8. 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. PMID:21615587

  9. Developing Leadership in a Multitype Library Consortium: Ten Years of SEFLIN Sun Seekers

    ERIC Educational Resources Information Center

    Curry, Elizabeth A.; Smithee, Jeannette

    2009-01-01

    The Southeast Florida Library and Information Network (SEFLIN) has presented the Sun Seeker Leadership Institute biennially since 1997. SEFLIN, a multitype library consortium headquartered in Boca Raton, Florida, was one of the first groups to sponsor a library leadership institute held as a monthly series of events over the period of a year. One…

  10. 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…

  11. 12 CFR 545.95 - What processing procedures apply to my home or branch office application or notice?

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 12 Banks and Banking 5 2010-01-01 2010-01-01 false What processing procedures apply to my home or branch office application or notice? 545.95 Section 545.95 Banks and Banking OFFICE OF THRIFT SUPERVISION, DEPARTMENT OF THE TREASURY FEDERAL SAVINGS ASSOCIATIONS-OPERATIONS § 545.95 What processing procedures apply to my home or branch...

  12. 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.

  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. 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.

  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. Evaluation of Annual Performance of Multi-type Air-conditioners for Buildings

    NASA Astrophysics Data System (ADS)

    Watanabe, Choyu; Ohashi, Ei-Ichiro; Hirota, Masafumi; Nagamatsu, Katsuaki; Nakayama, Hiroshi

    The partial thermal load performance tests of electric-motor driven multi-type air-conditioners for buildings, the rated cooling and heating capacities of which were 56 kW and 63 kW, respectively, were carried out using the air-enthalpy method testing apparatus. Based on the results of those tests, the applicability of JIS B 8616: 2006, which was developed for the estimation of the annual electricity consumption of packaged air-conditioners with rated cooling capacities less than 28 kW, to the multi-type air-conditioners with larger capacities were examined. It was found that JIS B 8616: 2006 generally overestimates COP under a relatively low thermal load operation. As a result, the annual electricity consumption is underestimated by JIS. The prediction error changes depending of the building uses, and it amounted to -17 % in the case of office and -6 % in the detached shop.

  18. 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).

  19. Genetic drift in populations governed by a Galton-Watson branching process.

    PubMed

    Burden, Conrad J; Simon, Helmut

    2016-06-01

    Most population genetics studies have their origins in a Wright-Fisher or some closely related fixed-population model in which each individual randomly chooses its ancestor. Populations which vary in size with time are typically modelled via a coalescent derived from Wright-Fisher, but use a nonlinear time-scaling driven by a deterministically imposed population growth. An alternate, arguably more realistic approach, and one which we take here, is to allow the population size to vary stochastically via a Galton-Watson branching process. We study genetic drift in a population consisting of a number of distinct allele types in which each allele type evolves as an independent Galton-Watson branching process. We find the dynamics of the population is determined by a single parameter κ0=(2m0/σ(2))logλ, where m0 is the initial population size, λ is the mean number of offspring per individual; and σ(2) is the variance of the number of offspring. For 0≲κ0≪1, the dynamics are close to those of Wright-Fisher, with the added property that the population is prone to extinction. For κ0≫1 allele frequencies and ancestral lineages are stable and individual alleles do not fix throughout the population. The existence of a rapid changeover regime at κ0≈1 enables estimates to be made, together with confidence intervals, of the time and population size of the era of mitochondrial Eve. PMID:27018000

  20. Stellar neutron capture cross section of the unstable s-process branching point {sup 151}Sm

    SciTech Connect

    Wisshak, K.; Voss, F.; Kaeppeler, F.; Krticka, M.; Raman, S.; Mengoni, A.; Gallino, R.

    2006-01-15

    The neutron capture cross sections of the radioactive isotope {sup 151}Sm and of natural samarium have been measured in the energy range from 3 keV to 225 keV at the Karlsruhe 3.7 MV Van de Graaff accelerator. Neutrons were produced via the {sup 7}Li(p,n){sup 7}Be reaction by bombarding metallic Li targets with a pulsed proton beam and capture events were registered with the Karlsruhe 4{pi} Barium Fluoride Detector. The cross sections were determined relative to the gold standard using a 206 mg sample of samarium oxide with 90% enrichment in {sup 151}Sm. Over most of the measured energy range uncertainties of {approx}2-3% could be achieved for the {sup 151}Sm/{sup 197}Au ratio. Maxwellian averaged neutron capture cross sections of {sup 151}Sm were calculated for thermal energies between kT = 8 keV and 100 keV with due consideration of the stellar enhancement factor and were found to be systematically larger than all previous theoretical predictions used in the analysis of the s-process branching at {sup 151}Sm. In the context of the branching analysis, an experimental determination of the stellar enhancement factor due to captures in thermally excited states is proposed, and the tentative determination of the p-process residual of {sup 152}Gd and a few other cases is discussed.

  1. The (n, α) Reaction in the s-process Branching Point {sup 59}Ni

    SciTech Connect

    Weiß, C.; Guerrero, C.; Griesmayer, E.; Andrzejewski, J.; Badurek, G.; Chiaveri, E.; Dressler, R.; Ganesan, S.; Jericha, E.; Käppeler, F.; Koehler, P.; Lederer, C.; Leeb, H.; Marganiec, J.; Pavlik, A.; Perkowski, J.; Rauscher, T.; and others

    2014-06-15

    The (n, α) reaction in the radioactive {sup 59}Ni is of relevance in nuclear astrophysics as {sup 59}Ni can be considered as the first branching point in the astrophysical s-process. Its relevance in nuclear technology is especially related to material embrittlement in stainless steel. However, there is a discrepancy between available experimental data and the evaluated nuclear data files for this reaction. At the n{sub T}OF facility at CERN, a dedicated system based on sCVD diamond diodes was set up to measure the {sup 59}Ni(n, α){sup 56}Fe cross section. The results of this measurement, with special emphasis on the dominant resonance at 203 eV, are presented here.

  2. 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.

  3. 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

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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). ...

  5. Nuclear correlations and neutrino emissivity from the neutron branch of the modified Urca process

    NASA Astrophysics Data System (ADS)

    Dehghan Niri, A.; Moshfegh, H. R.; Haensel, P.

    2016-04-01

    The neutrino emissivity from the neutron branch of the modified Urca process is calculated. The nuclear correlation effects are taken into account by employing the correlation functions extracted from the lowest-order constrained variational (LOCV) method applied to asymmetric nuclear matter. Two-body nucleon interaction is modeled by a realistic Argonne AV18 potential. In order to get consistency with semiempirical saturation parameters of nuclear matter and the existence of 2 M⊙ pulsars, we add a phenomenological Urbana UIX three-body potential to the nucleon Hamiltonian and apply a newly formulated version of the LOCV method that allows for three-body nucleon interactions. We find that at fixed temperature neutrino emissivity is a (weakly) decreasing function of density, due to quenching of the contribution from tensor correlations with increasing density. This is in variance with all previous works. We also find that three-body forces allow for the opening of the direct Urca process at nucleon density 0.3 fm-3 .

  6. A Branching Process to Characterize the Dynamics of Stem Cell Differentiation

    PubMed Central

    Míguez, David G.

    2015-01-01

    The understanding of the regulatory processes that orchestrate stem cell maintenance is a cornerstone in developmental biology. Here, we present a mathematical model based on a branching process formalism that predicts average rates of proliferative and differentiative divisions in a given stem cell population. In the context of vertebrate neurogenesis, the model predicts complex non-monotonic variations in the rates of pp, pd and dd modes of division as well as in cell cycle length, in agreement with experimental results. Moreover, the model shows that the differentiation probability follows a binomial distribution, allowing us to develop equations to predict the rates of each mode of division. A phenomenological simulation of the developing spinal cord informed with the average cell cycle length and division rates predicted by the mathematical model reproduces the correct dynamics of proliferation and differentiation in terms of average numbers of progenitors and differentiated cells. Overall, the present mathematical framework represents a powerful tool to unveil the changes in the rate and mode of division of a given stem cell pool by simply quantifying numbers of cells at different times. PMID:26286123

  7. Measurements of conversion electrons in the s-process branching point nucleus 176Lu

    NASA Astrophysics Data System (ADS)

    Battaglia, A.; Tan, W.; Avetisyan, R.; Casarella, C.; Gyurijinyan, A.; Manukyan, K. V.; Marley, S. T.; Nystrom, A.; Paul, N.; Siegl, K.; Smith, K.; Smith, M. K.; Strauss, S. Y.; Aprahamian, A.

    2016-05-01

    Conversion coefficients, gamma-gamma and gamma-electron coincidences were measured in the s-process branching point nucleus 176Lu . Our goal was to determine the multipolarities of the γ -ray transitions that connect the high and low K states of 176Lu . This 176Lu nucleus has a long-lived ground state ( K=7- of 37.6Gy, a short-lived isomeric state ( K=0- at 122.8keV with half-life of 3.6h, as well as a 58μs isomer at 1588keV ( K=14+ . The excitation structure of this nucleus contains bands of intermediate spins of both positive and negative parities. The intermediate states can under certain stellar temperatures completely change the equilibrium between the isomer and ground state of 176Lu and change the abundance of this nucleus. We populated 37 previously known levels in this nucleus via the 176Yb ( p, n reaction and measured 42 conversion coefficients for γ -ray transitions including 17 of them for the first time.

  8. 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…

  9. 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…

  10. 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.

  11. 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.

  12. Progression features of a stepped leader process with four grounded leader branches

    NASA Astrophysics Data System (ADS)

    Qie, Xiushu; Kong, Xiangzhen

    2007-03-01

    The propagation features of stepped leader with four grounded branches during a negative CG flash have been analyzed by using the data from a high-speed digital camera with 1 ms time resolution in correlation with wide-band electric field change signatures. Four branches that initiated from a main leader trunk connected to ground in sequence and induced four separate return strokes. The propagation speed of four grounded leader branches shows an increase tendency when they progressed downward to ground. The average 2-D speed of four grounded branches was estimated to be about 1.1 × 105 m/s. The electric field changes caused by the stepped leader were characterized by clustered pulses near the time of return stroke. Each cluster of pulses was composed of 3-4 pulses with an average time interval in a cluster of about 7.7 μs, and the time interval between two first pulses in two adjacent clusters was 30.1 μs.

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  14. 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

  15. 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.

  16. Optimal multi-type sensor placement for response and excitation reconstruction

    NASA Astrophysics Data System (ADS)

    Zhang, C. D.; Xu, Y. L.

    2016-01-01

    The need to perform dynamic response reconstruction always arises as the measurement of structural response is often limited to a few locations, especially for a large civil structure. Besides, it is usually very difficult, if not impossible, to measure external excitations under the operation condition of a structure. This study presents an algorithm for optimal placement of multi-type sensors, including strain gauges, displacement transducers and accelerometers, for the best reconstruction of responses of key structural components where there are no sensors installed and the best estimation of external excitations acting on the structure at the same time. The algorithm is developed in the framework of Kalman filter with unknown excitation, in which minimum-variance unbiased estimates of the generalized state of the structure and the external excitations are obtained by virtue of limited sensor measurements. The structural responses of key locations without sensors can then be reconstructed with the estimated generalized state and excitation. The asymptotic stability feature of the filter is utilized for optimal sensor placement. The number and spatial location of the multi-type sensors are determined by adding the optimal sensor which gains the maximal reduction of the estimation error of reconstructed responses. For the given mode number in response reconstruction and the given locations of external excitations, the optimal multi-sensor placement achieved by the proposed method is independent of the type and time evolution of external excitation. A simply-supported overhanging steel beam under multiple types of excitation is numerically studied to demonstrate the feasibility and superiority of the proposed method, and the experimental work is then carried out to testify the effectiveness of the proposed method.

  17. 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

  18. 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

  19. Shoot branching.

    PubMed

    Ward, Sally P; Leyser, Ottoline

    2004-02-01

    The mature form of a plant shoot system is an expression of several genetically controlled traits, many of which are also environmentally regulated. A major component of this architectural variation is the degree of shoot branching. Recent results indicate conserved mechanisms for shoot branch development across the monocots and eudicots. The existence of a novel long-range branch-inhibiting signal has been inferred from studies of branching mutants in pea and Arabidopsis. PMID:14732444

  20. 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.

  1. 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.

  2. 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

  3. 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

  4. 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

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

    PubMed

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

    2015-07-01

    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. 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.

  7. Evaluation of Annual Performance of Multi-type Air-Conditioners for Buildings

    NASA Astrophysics Data System (ADS)

    Watanabe, Choyu; Ohashi, Ei-Ichiro; Nagamatsu, Katsuaki; Nakayama, Hiroshi; Hirota, Masafumi

    In this paper, firstly the results of the partial thermal load performance tests of multi-type air-conditioners for buildings were shown. Tests were conducted by using the air-enthalpy method testing apparatus. Two types of air-conditioners, heat pump driven by electric motors (EHP) and that driven by gas engines (GHP), with a rated cooling capacity of 56 kW were tested. The coefficient of performance (COP) and the annual energy consumption measured by the above mentioned tests were closely compared with those predicted by JIS. In EHP,the measured COP indicates the maximum when the indoor thermal load is about 50% of the rated capacity, while COP in GHP decreases gradually as the thermal load is decreased. Based on these results, we examined the accuracies of COP and the annual energy consumption predicted by JIS. It was found that in both EHP and GHP the current calculating method prescribed in JIS could not duplicate the COP decrease that appeared under the low thermal load conditions. As a result, the annual energy consumption is seriously underestimated by JIS. The prediction errors of the annual energy consumption amounted to about 17% for EHP and 38% for GHP

  8. Evaluation of Annual Performance of Multi-type Air-Conditioners for Buildings

    NASA Astrophysics Data System (ADS)

    Hirota, Masafumi; Watanabe, Choyu; Furukawa, Masahide; Nagamatsu, Katsuaki

    The partial load performance tests of multi-type package air-conditioners for buildings powered by electric motors, the rating cooling performance of which was 56 kW, were carried out by using the air-enthalpy method testing apparatus. The coefficient of performance (COP) and annual energy consumption measured by those tests were closely compared with those estimated from the current calculating method (JIS B 8616:2006). It was found that the performance of the air-conditioner changes depending on the outdoor air temperature and the indoor thermal load. The current calculating method could not reproduce the deteriorations of COP that appeared under the low thermal load condition in both the cooling and heating seasons. As a result it seriously underestimated the annual energy consumption; the error amounted to as large as about 20 % of the measured annual electric power consumption. Based on these results, we have proposed new testing conditions for the performance evaluation and a calculation method of the annual energy consumption that can improve the accuracy of the estimation of the annual energy consumption.

  9. 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.

  10. A Framework for Analysis of Abortive Colony Size Distributions Using a Model of Branching Processes in Irradiated Normal Human Fibroblasts

    PubMed Central

    Kawaguchi, Isao; Ouchi, Noriyuki B.; Hara, Takamitsu; Kobayashi, Yasuhiko; Saito, Kimiaki

    2013-01-01

    Background Clonogenicity gives important information about the cellular reproductive potential following ionizing irradiation, but an abortive colony that fails to continue to grow remains poorly characterized. It was recently reported that the fraction of abortive colonies increases with increasing dose. Thus, we set out to investigate the production kinetics of abortive colonies using a model of branching processes. Methodology/Principal Findings We firstly plotted the experimentally determined colony size distribution of abortive colonies in irradiated normal human fibroblasts, and found the linear relationship on the log-linear or log-log plot. By applying the simple model of branching processes to the linear relationship, we found the persistent reproductive cell death (RCD) over several generations following irradiation. To verify the estimated probability of RCD, abortive colony size distribution (≤15 cells) and the surviving fraction were simulated by the Monte Carlo computational approach for colony expansion. Parameters estimated from the log-log fit demonstrated the good performance in both simulations than those from the log-linear fit. Radiation-induced RCD, i.e. excess probability, lasted over 16 generations and mainly consisted of two components in the early (<3 generations) and late phases. Intriguingly, the survival curve was sensitive to the excess probability over 5 generations, whereas abortive colony size distribution was robust against it. These results suggest that, whereas short-term RCD is critical to the abortive colony size distribution, long-lasting RCD is important for the dose response of the surviving fraction. Conclusions/Significance Our present model provides a single framework for understanding the behavior of primary cell colonies in culture following irradiation. PMID:23894635

  11. 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.

  12. Barium Isotopic Composition of Mainstream Silicon Carbides from Murchison: Constraints for s-process Nucleosynthesis in Asymptotic Giant Branch Stars

    NASA Astrophysics Data System (ADS)

    Liu, Nan; Savina, Michael R.; Davis, Andrew M.; Gallino, Roberto; Straniero, Oscar; Gyngard, Frank; Pellin, Michael J.; Willingham, David G.; Dauphas, Nicolas; Pignatari, Marco; Bisterzo, Sara; Cristallo, Sergio; 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(138Ba/136Ba) values are found, down to -400‰, which can only be modeled with a flatter 13C profile within the 13C pocket than is normally used. The dependence of δ(138Ba/136Ba) predictions on the distribution of 13C within the pocket in asymptotic giant branch (AGB) models allows us to probe the 13C profile within the 13C pocket and the pocket mass in AGB stars. In addition, we provide constraints on the 22Ne(α, n)25Mg rate in the stellar temperature regime relevant to AGB stars, based on δ(134Ba/136Ba) values of mainstream grains. We found two nominally mainstream grains with strongly negative δ(134Ba/136Ba) 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, 130Ba and 132Ba, in single SiC grains. These isotopes are destroyed in the s process in AGB stars. By comparing their abundances with respect to that of 135Ba, we conclude that there is no measurable decay of 135Cs (t 1/2 = 2.3 Ma) to 135Ba in individual SiC grains, indicating condensation of barium, but not cesium into SiC grains before 135Cs decayed.

  13. Biological and chemical assessment of M-Area process discharge to TIM's Branch, June 1985--December 1986

    SciTech Connect

    Carlton, W.H. ); Starkel, W.M.; Giffin, M.; Trapp, K.E. )

    1987-03-01

    The production facilities of M-Area process uranium, lithium, and aluminum into fuel and target components for nuclear reactors at the Savannah River Plant (SRP). These processes produce wastewaters that contain dissolved metals, solvents, and nitric acid. Beginning in July 1985, wastewater was diverted to the M-Area Liquid Effluent Treatment Facility (LETF), which treats the waste via precipitation, filtration, and neutralization. Major constituents of the LETF discharge include nitrate (as NaNO{sub 3}), phosphorus, total suspended solids, and trace amounts of aluminum, lead, nickel, iron, and uranium. In addition to the intermittent LETF discharge, the A-014 outfall also has received a continuous discharge of noncontact cooling water (700 to 2500 gpm) since 1982 and effluent from the M-Area Ground Water Recovery Action (MAGWRA) air stripper (375 gpm) since September 1985. These effluents consist of trace amounts of (trichloroethylene, tetrachloroethylene, and 1, 1, 1-trichloroethane) in the MAGWRA effluent. In June 1985, a chemical and biological monitoring program was initiated to determine if M-Area discharges are a significant environmental hazard to Tim's Branch. The main concerns are whether the discharge is toxic to aquatic life and whether high levels of nitrate in the discharge from the M-Area Liquid Effluent Treatment Facility (LETF) will cause eutrophication of the aquatic system.

  14. 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.

  15. Model for Studying Branching Processes, Multiplicity Distributions, and Non-Poissonian Fluctuations in Heavy-Ion Collisions

    SciTech Connect

    Mekjian, A. Z.

    2001-01-08

    A change is made in a statistical framework by introducing a set of variables called ancestral or stochastic. This leads to an underlying dynamics based on branching laws, lines of descent in an hierarchical topology, period doublings, cascades, and clans. Above a certain branching probability, a percolative feature suddenly appears. Power laws emerge and cascade points arise and end at golden mean (5 -1)/2 .

  16. The bisexual branching process with population-size dependent mating as a mathematical model to describe phenomena concerning to inhabit or re-inhabit environments with animal species.

    PubMed

    Mota, M; del Puerto, I; Ramos, A

    2007-03-01

    We consider the bisexual Galton-Watson branching process with population-size dependent mating as a mathematical model adequate for the description of some natural phenomena. More specifically we are interested in studying some questions about the problem of populating an environmental with new animal species or re-populating it with species which have previously disappeared. PMID:16197966

  17. Growth patterns in mesophotic octocorals: Timing the branching process in the highly-valuable Mediterranean Corallium rubrum

    NASA Astrophysics Data System (ADS)

    Benedetti, Maria Carla; Priori, Cristina; Erra, Fabrizio; Santangelo, Giovanni

    2016-03-01

    This study examined colony growth in the long-lived red coral Corallium rubrum, a slow growing octocoral endemic to the Mediterranean Sea and neighboring Atlantic areas and one of the most valuable of all marine species. Age and growth rate were determined on 165 sections of colony bases and branches by means of a validated age dating method in populations living between 50 and 130 m in the NW Mediterranean. The ratio between minimum and maximum diameter remained constant, indicating proportional growth of colony bases. No significant difference was found between the growth rate of bases and branches. A significantly different branching pattern (colony height/number of branches) and average growth rate were found between the colonies of the different geographic areas. As growth rate decreases with age, this was due to the different age structure of the two samples. The maximum lifespan was found to be 106 years, a value not determined previously for C. rubrum colonies, and the average age of colonies at first branching was about 10 years. Linear growth varied widely between colonies as well as between branches in the same colony, confirming the lack of any strict relation between height and age. The study illustrates the growth of a mesophotic, heavily exploited Corallidae.

  18. 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.

  19. 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

  20. Branch retinal vein occlusion.

    PubMed

    Hamid, Sadaf; Mirza, Sajid Ali; Shokh, Ishrat

    2008-01-01

    Retinal vein occlusions (RVO) are the second commonest sight threatening vascular disorder. Branch retinal vein occlusion (BRVO) and central retinal vein occlusion (CRVO) are the two basic types of vein occlusion. Branch retinal vein occlusion is three times more common than central retinal vein occlusion and- second only to diabetic retinopathy as the most common retinal vascular cause of visual loss. The origin of branch retinal vein occlusion undoubtedly includes both systemic factors such as hypertension and local anatomic factors such as arteriovenous crossings. Branch retinal vein occlusion causes a painless decrease in vision, resulting in misty or distorted vision. Current treatment options don't address the underlying aetiology of branch retinal vein occlusion. Instead they focus on treating sequelae of the occluded venous branch, such as macular oedema, vitreous haemorrhage and traction retinal detachment from neovascularization. Evidences suggest that the pathogenesis of various types of retinal vein occlusion, like many other ocular vascular occlusive disorders, is a multifactorial process and there is no single magic bullet that causes retinal vein occlusion. A comprehensive management of patients with retinal vascular occlusions is necessary to correct associated diseases or predisposing abnormalities that could lead to local recurrences or systemic event. Along with a review of the literature, a practical approach for the management of retinal vascular occlusions is required, which requires collaboration between the ophthalmologist and other physicians: general practitioner, cardiologist, internist etc. as appropriate according to each case. PMID:19385476

  1. Biological and chemical assessment of M-Area process discharge to Tim's Branch: June 1985-December 1986

    SciTech Connect

    Specht, W.L.; Pickett, J.B.; Muska, C.F.; Starkel, W.M.; Giffin, M.; Trapp, K.E.

    1987-05-01

    This study addresses the effects of the A-014 outfall on the chemistry and biota of Tim's Branch and Upper Three Runs Creek from June 1985 through December 1986. In addition to analyses for chemical parameters, the periphyton and macroinvertebrate communities on each site were sampled to assess the impact of the M-Area discharges on the overall condition of these communities. Acute laboratory toxicity tests were conducted on noncontact cooling water/air stripper water and noncontact cooling water/air stripper water/Liquid Effluent Treatment Facility (LETF) effluent using bluegill sunfish and Daphnia pulex. The data indicate no adverse impact on the water chemistry, water quality, or aquatic communities of the Tim's Branch/Upper Three Runs system due to discharges from the A-014 outfall after startup of the M-Area Project Air Stripper and the M-Area Liquid Effluent Treatment Facility.

  2. 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.

  3. Virtual fuzzy in-process control of Y-shape tube hydroforming with different branch top shapes

    NASA Astrophysics Data System (ADS)

    Manabe, Ken-ichi; Chen, Xu; Kobayashi, Dai

    2014-10-01

    In this study, a new counter punch shape was designed and applied to Y-shape hydroforming to obtain a Y-shape tube with uniform wall thickness. The new counter punch shape effect in Y-shape hydroforming using fuzzy control was investigated in finite element simulation. As a result, the wall thickness thinning in the branch top was restrained and the wall thickness thickening in the die shoulder of obtuse angle side was restrained. The results suggested that the wall thickness could be more uniform by using the new counter punch.

  4. 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.

  5. Child multi-type maltreatment and associated depression and PTSD symptoms: The role of social support and stress

    PubMed Central

    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 stress disorder (PTSD). Method Participants were 100 women recruited from an inner-city gynecological treatment center for low-income women. Data were analyzed via structural equation modeling (SEM) with Lisrel 8.0. Results CMM was directly predictive of decreased social support and increased stress in adulthood. CMM was also directly predictive of PTSD symptoms, but not depression symptoms in adulthood. Social support partially mediated the relationship between CMM and adult PTSD symptoms, and stress fully mediated the relationship between CMM and adult symptoms of depression. Conclusions Findings support both direct and mediational effects of social resources on adult depression and PTSD symptoms in women with histories of CMM, suggesting that resources are key factors in psychological adjustment of CMM victims. PMID:17215039

  6. Cross-section measurements of the 86Kr(γ,n) reaction to probe the s-process branching at 85Kr.

    PubMed

    Raut, R; Tonchev, A P; Rusev, G; Tornow, W; Iliadis, C; Lugaro, M; Buntain, J; Goriely, S; Kelley, J H; Schwengner, R; Banu, A; Tsoneva, N

    2013-09-13

    We have carried out photodisintegration cross-section measurements on 86Kr using monoenergetic photon beams ranging from the neutron separation energy, S(n) = 9.86  MeV, to 13 MeV. We combine our experimental 86Kr(γ,n)85Kr cross section with results from our recent 86Kr(γ,γ') measurement below the neutron separation energy to obtain the complete nuclear dipole response of 86Kr. The new experimental information is used to predict the neutron capture cross section of 85Kr, an important branching point nucleus on the abundance flow path during s-process nucleosynthesis. Our new and more precise 85Kr(n,γ)86Kr cross section allows us to produce more precise predictions of the 86Kr abundance from s-process models. In particular, we find that the models of the s process in asymptotic giant branch stars of mass <1.5M⊙, where the 13C neutron source burns convectively rather than radiatively, represent a possible solution for the highest 86Kr:82Kr ratios observed in meteoritic stardust SiC grains. PMID:24074078

  7. 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.

  8. Nine new metal-poor stars on the subgiant and red horizontal branches with high levels of r-process enhancement

    NASA Astrophysics Data System (ADS)

    Roederer, Ian U.; Cowan, John J.; Preston, George W.; Shectman, Stephen A.; Sneden, Christopher; Thompson, Ian B.

    2014-12-01

    We report the discovery of nine metal-poor stars with high levels of r-process enhancement (+0.81 ≤ [Eu/Fe] ≤ +1.13), including six subgiants and three stars on the red horizontal branch. We also analyse four previously known r-process-enhanced metal-poor red giants. From this sample of 13 stars, we draw the following conclusions. (1) High levels of r-process enhancement are found in a broad range of stellar evolutionary states, reaffirming that this phenomenon is not associated with a chemical peculiarity of red giant atmospheres. (2) Only 1 of 10 stars observed at multiple epochs shows radial-velocity variations, reaffirming that stars with high levels of r-process enhancement are not preferentially found among binaries. (3) Only 2 of the 13 stars are highly enhanced in C and N, indicating that there is no connection between high levels of r-process enhancement and high levels of C and N. (4) The dispersions in [Sr/Ba] and [Sr/Eu] are larger than the dispersions in [Ba/Eu] and [Yb/Eu], suggesting that the elements below the second r-process peak do not always scale with those in the rare Earth domain, even within the class of highly-r-process-enhanced stars. (5) The light-element (12 ≤ Z ≤ 30) abundances of highly-r-process-enhanced stars are indistinguishable from those with normal levels of r-process material at the limit of our data, 3.5 per cent (0.015 dex) on average. The nucleosynthetic sites responsible for the large r-process enhancements did not produce any detectable light-element abundance signatures distinct from normal core-collapse supernovae.

  9. COMPUTER AIDED CHEMICAL PROCESS DESIGN METHODOLOGIES FOR POLLUTION REDUCTION(SYSTEMS ANALYSIS BRANCH, SUSTAINABLE TECHNOLOGY DIVISION, NRMRL)

    EPA Science Inventory

    The objective of the project is to develop computer optimization and simulation methodologies for the design of economical chemical manufacturing processes with a minimum of impact on the environment. The computer simulation and optimization tools developed in this project can be...

  10. Half-lives and branchings for β-delayed neutron emission for neutron-rich Co-Cu isotopes in the r-process

    NASA Astrophysics Data System (ADS)

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

    2010-08-01

    The β decays of very neutron-rich nuclides in the Co-Zn region were studied experimentally at the National Superconducting Cyclotron Laboratory using the NSCL β-counting station in conjunction with the neutron detector NERO. We measured the branchings for β-delayed neutron emission (Pn values) for Co74 (18±15%) and Ni75-77 (10±2.8%, 14±3.6%, and 30±24%, respectively) for the first time, and remeasured the Pn values of Cu77-79, Zn79,81, and Ga82. For Cu77-79 and for Zn81 we obtain significantly larger Pn 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 Co75 (30±11 ms) and Cu80 (170-50+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.

  11. Multidimensional treatment of stochastic solvent dynamics in photoinduced proton-coupled electron transfer processes: sequential, concerted, and complex branching mechanisms.

    PubMed

    Soudackov, Alexander V; Hazra, Anirban; Hammes-Schiffer, Sharon

    2011-10-14

    A theoretical approach for the multidimensional treatment of photoinduced proton-coupled electron transfer (PCET) processes in solution is presented. This methodology is based on the multistate continuum theory with an arbitrary number of diabatic electronic states representing the relevant charge distributions in a general PCET system. The active electrons and transferring proton(s) are treated quantum mechanically, and the electron-proton vibronic free energy surfaces are represented as functions of multiple scalar solvent coordinates corresponding to the single electron and proton transfer reactions involved in the PCET process. A dynamical formulation of the dielectric continuum theory is used to derive a set of coupled generalized Langevin equations of motion describing the time evolution of these collective solvent coordinates. The parameters in the Langevin equations depend on the solvent properties, such as the dielectric constants, relaxation time, and molecular moment of inertia, as well as the solute properties. The dynamics of selected intramolecular nuclear coordinates, such as the proton donor-acceptor distance or a torsional angle within the PCET complex, may also be included in this formulation. A surface hopping method in conjunction with the Langevin equations of motion is used to simulate the nonadiabatic dynamics on the multidimensional electron-proton vibronic free energy surfaces following photoexcitation. This theoretical treatment enables the description of both sequential and concerted mechanisms, as well as more complex processes involving a combination of these mechanisms. The application of this methodology to a series of model systems corresponding to collinear and orthogonal PCET illustrates fundamental aspects of these different mechanisms and elucidates the significance of proton vibrational relaxation and nonequilibrium solvent dynamics. PMID:22010706

  12. The s-process in low-metallicity stars - III. Individual analysis of CEMP-s and CEMP-s/r with asymptotic giant branch models

    NASA Astrophysics Data System (ADS)

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

    2012-05-01

    We provide an individual analysis of 94 carbon-enhanced metal-poor stars showing an s-process enrichment (CEMP-s) collected from the literature. The s-process enhancement observed in these stars is ascribed to mass transfer by stellar winds in a binary system from a more massive companion evolving faster towards the asymptotic giant branch (AGB) phase. The theoretical AGB nucleosynthesis models have been presented in Bisterzo et al. (Paper I of this series). Several CEMP-s show an enhancement in both s- and r-process elements (CEMP-s/r). In order to explain the peculiar abundances observed in CEMP-s/r, we assume that the molecular cloud from which CEMP-s formed was previously enriched in r-elements by supernova pollution. A general discussion and the method adopted in order to interpret the observations have been provided in Bisterzo et al. (Paper II of this series). We present in this paper a detailed study of spectroscopic observations of individual stars. We consider all elements from carbon to bismuth, with particular attention to the three s-process peaks, ls (Y, Zr), hs (La, Nd, Sm) and Pb, and their ratios [hs/ls] and [Pb/hs]. The presence of an initial r-process contribution may be typically evaluated by [La/Eu]. We found possible agreements between theoretical predictions and spectroscopic data. In general, the observed [Na/Fe] (and [Mg/Fe]) provides information on the AGB initial mass, while [hs/ls] and [Pb/hs] are mainly indicators of the s-process efficiency. A range of 13C-pocket strengths are required to interpret the observations. However, major discrepancies between models and observations exist. We highlight star by star the agreements and the main problems encountered and, when possible, we suggest potential indications for further studies. These discrepancies provide starting points of debate for unsolved problems in which spectroscopic and theoretical studies may intervene.

  13. Puzzling Origin of CEMP-r/s Stars: An Interpretation of Abundance and Enrichment of s- and r-Process Elements from Asymptotic Giant Branch Supernovae

    NASA Astrophysics Data System (ADS)

    Zhang, Jiang; Zhao, Fang; Chen, Yanping; Cui, Wenyuan; Zhang, Bo

    2013-12-01

    CEMP-r/s stars at low metallicity are known as double-enhanced stars that show enhancements of both r-process and s-process elements. The chemical abundances of these very metal-poor stars provide us a lot of information for putting new restraints on models of neutron-capture processes. In this article, we put forward an accreted scenario in which the double enrichment of r-process and s-process elements is caused by a former intermediate-mass Asymptotic Giant Branch (AGB) companion in a detached binary system. As the AGB superwind is only present at the ultimate phase of AGB stars, there is thus a lot of potential that the degenerate-core mass of an intermediate-mass AGB star reaches the Chandrasekhar limit before the AGB superwind. In these circumstances, both s-process elements produced in the AGB shell and r-process elements synthesized in the subsequent explosion would be sprayed contemporaneously and accreted by its companion. Despite similarity to physical conditions of a core-collapse supernova, a major focus in this scenario is the degenerate C-O core surrounded by an envelope of a former intermediate-mass AGB donor that may collapse and explode. Due to the existence of an outer envelope, r-process nucleosynthesis is expected to occur. Hypothesizing the material-rich europium (Eu) accreted by the secondary via the wind from the supernova to be in proportion to the geometric fraction of the companion with respect to the exploding donor star, we find that the estimated yield of Eu (as representative of r-process elements) per AGB supernova event is about 1 × 10-9 M ⊙ ˜ 5 × 10-9 M ⊙. Using the yields of Eu, the overabundance of r-process elements in CEMP-r/s stars can be accounted for. The calculated results show that the value of parameter f , standing for efficiency of wind pollution from the AGB supernova, will reach about 104, which means that the enhanced factor is much larger than unity due to the impact of gravity of the donor and the result of

  14. 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.

  15. Prediction of Multi-Type Membrane Proteins in Human by an Integrated Approach

    PubMed Central

    Chen, Lei; Zhang, Ning; Huang, Tao; Cai, Yu-Dong

    2014-01-01

    Membrane proteins were found to be involved in various cellular processes performing various important functions, which are mainly associated to their types. However, it is very time-consuming and expensive for traditional biophysical methods to identify membrane protein types. Although some computational tools predicting membrane protein types have been developed, most of them can only recognize one kind of type. Therefore, they are not as effective as one membrane protein can have several types at the same time. To our knowledge, few methods handling multiple types of membrane proteins were reported. In this study, we proposed an integrated approach to predict multiple types of membrane proteins by employing sequence homology and protein-protein interaction network. As a result, the prediction accuracies reached 87.65%, 81.39% and 70.79%, respectively, by the leave-one-out test on three datasets. It outperformed the nearest neighbor algorithm adopting pseudo amino acid composition. The method is anticipated to be an alternative tool for identifying membrane protein types. New metrics for evaluating performances of methods dealing with multi-label problems were also presented. The program of the method is available upon request. PMID:24676214

  16. Characterizing Branched Flow

    NASA Astrophysics Data System (ADS)

    Drury, Byron; Klales, Anna; Heller, Eric

    2014-03-01

    Branched flow appears in a variety of physical systems spanning length scales from microns to thousands of kilometers. For instance, it plays an important role in both electron transport in two dimensional electron gases and the propagation of tsunamis in the ocean. Branches have typically been identified with caustics in the theoretical literature, but concentrations of flux recognizable as branches can arise from other mechanisms. We propose a generalized definition of branching based on a local measure of the stability of trajectories. We analytically and numerically study the characteristics of Hamiltonian flow in phase space and characterize the relationship between branch formation and trajectory stability.

  17. 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

    2014-04-01

    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. PMID:24606576

  18. Mechanical properties of branched actin filaments

    NASA Astrophysics Data System (ADS)

    Razbin, Mohammadhosein; Falcke, Martin; Benetatos, Panayotis; Zippelius, Annette

    2015-07-01

    Cells moving on a two dimensional substrate generate motion by polymerizing actin filament networks inside a flat membrane protrusion. New filaments are generated by branching off existing ones, giving rise to branched network structures. We investigate the force-extension relation of branched filaments, grafted on an elastic structure at one end and pushing with the free ends against the leading edge cell membrane. Single filaments are modeled as worm-like chains, whose thermal bending fluctuations are restricted by the leading edge cell membrane, resulting in an effective force. Branching can increase the stiffness considerably; however the effect depends on branch point position and filament orientation, being most pronounced for intermediate tilt angles and intermediate branch point positions. We describe filament networks without cross-linkers to focus on the effect of branching. We use randomly positioned branch points, as generated in the process of treadmilling, and orientation distributions as measured in lamellipodia. These networks reproduce both the weak and strong force response of lamellipodia as measured in force-velocity experiments. We compare properties of branched and unbranched networks. The ratio of the network average of the force per branched filament to the average force per unbranched filament depends on the orientation distribution of the filaments. The ratio exhibits compression dependence and may go up to about 4.5 in networks with a narrow orientation distribution. With orientation distributions measured in lamellipodia, it is about two and essentially independent from network compression, graft elasticity and filament persistence length.

  19. Mechanical properties of branched actin filaments.

    PubMed

    Razbin, Mohammadhosein; Falcke, Martin; Benetatos, Panayotis; Zippelius, Annette

    2015-07-01

    Cells moving on a two dimensional substrate generate motion by polymerizing actin filament networks inside a flat membrane protrusion. New filaments are generated by branching off existing ones, giving rise to branched network structures. We investigate the force-extension relation of branched filaments, grafted on an elastic structure at one end and pushing with the free ends against the leading edge cell membrane. Single filaments are modeled as worm-like chains, whose thermal bending fluctuations are restricted by the leading edge cell membrane, resulting in an effective force. Branching can increase the stiffness considerably; however the effect depends on branch point position and filament orientation, being most pronounced for intermediate tilt angles and intermediate branch point positions. We describe filament networks without cross-linkers to focus on the effect of branching. We use randomly positioned branch points, as generated in the process of treadmilling, and orientation distributions as measured in lamellipodia. These networks reproduce both the weak and strong force response of lamellipodia as measured in force-velocity experiments. We compare properties of branched and unbranched networks. The ratio of the network average of the force per branched filament to the average force per unbranched filament depends on the orientation distribution of the filaments. The ratio exhibits compression dependence and may go up to about 4.5 in networks with a narrow orientation distribution. With orientation distributions measured in lamellipodia, it is about two and essentially independent from network compression, graft elasticity and filament persistence length. PMID:26040560

  20. 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.

  1. 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

  2. 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. PMID:24010026

  3. 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

  4. 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.

  5. Branch Mode Selection during Early Lung Development

    PubMed Central

    Menshykau, Denis; Kraemer, Conradin; Iber, Dagmar

    2012-01-01

    Many organs of higher organisms, such as the vascular system, lung, kidney, pancreas, liver and glands, are heavily branched structures. The branching process during lung development has been studied in great detail and is remarkably stereotyped. The branched tree is generated by the sequential, non-random use of three geometrically simple modes of branching (domain branching, planar and orthogonal bifurcation). While many regulatory components and local interactions have been defined an integrated understanding of the regulatory network that controls the branching process is lacking. We have developed a deterministic, spatio-temporal differential-equation based model of the core signaling network that governs lung branching morphogenesis. The model focuses on the two key signaling factors that have been identified in experiments, fibroblast growth factor (FGF10) and sonic hedgehog (SHH) as well as the SHH receptor patched (Ptc). We show that the reported biochemical interactions give rise to a Schnakenberg-type Turing patterning mechanisms that allows us to reproduce experimental observations in wildtype and mutant mice. The kinetic parameters as well as the domain shape are based on experimental data where available. The developed model is robust to small absolute and large relative changes in the parameter values. At the same time there is a strong regulatory potential in that the switching between branching modes can be achieved by targeted changes in the parameter values. We note that the sequence of different branching events may also be the result of different growth speeds: fast growth triggers lateral branching while slow growth favours bifurcations in our model. We conclude that the FGF10-SHH-Ptc1 module is sufficient to generate pattern that correspond to the observed branching modes. PMID:22359491

  6. Branch mode selection during early lung development.

    PubMed

    Menshykau, Denis; Kraemer, Conradin; Iber, Dagmar

    2012-01-01

    Many organs of higher organisms, such as the vascular system, lung, kidney, pancreas, liver and glands, are heavily branched structures. The branching process during lung development has been studied in great detail and is remarkably stereotyped. The branched tree is generated by the sequential, non-random use of three geometrically simple modes of branching (domain branching, planar and orthogonal bifurcation). While many regulatory components and local interactions have been defined an integrated understanding of the regulatory network that controls the branching process is lacking. We have developed a deterministic, spatio-temporal differential-equation based model of the core signaling network that governs lung branching morphogenesis. The model focuses on the two key signaling factors that have been identified in experiments, fibroblast growth factor (FGF10) and sonic hedgehog (SHH) as well as the SHH receptor patched (Ptc). We show that the reported biochemical interactions give rise to a Schnakenberg-type Turing patterning mechanisms that allows us to reproduce experimental observations in wildtype and mutant mice. The kinetic parameters as well as the domain shape are based on experimental data where available. The developed model is robust to small absolute and large relative changes in the parameter values. At the same time there is a strong regulatory potential in that the switching between branching modes can be achieved by targeted changes in the parameter values. We note that the sequence of different branching events may also be the result of different growth speeds: fast growth triggers lateral branching while slow growth favours bifurcations in our model. We conclude that the FGF10-SHH-Ptc1 module is sufficient to generate pattern that correspond to the observed branching modes. PMID:22359491

  7. INDUSTRIAL MULTIMEDIA BRANCH (SUSTAINABLE TECHNOLOGY DIVISION, NRMRL)

    EPA Science Inventory

    The mission of NRMRL's Industrial Multimedia Branch (IMB) is to develop, demonstrate, and evaluate timely and integrated innovative engineering and scientific approaches to reduce air, water, and land toxic pollution generated by the production. processing, and use of materials. ...

  8. 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)

  9. 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

  10. Extreme horizontal branch stars

    NASA Astrophysics Data System (ADS)

    Heber, U.

    A review is presented on the properties, origin and evolutionary links of hot subluminous stars which are generally believed to be extreme Horizontal Branch stars or closely related objects. They exist both in the disk and halo populations (globular clusters) of the Galaxy. Amongst the field stars a large fraction of sdBs are found to reside in close binaries. The companions are predominantly white dwarfs, but also low mass main sequence stars are quite common. Systems with sufficiently massive white dwarf companions may qualify as Supernova Ia progenitors. Recently evidence has been found that the masses of some unseen companions might exceed the Chandrasekhar mass, hence they must be neutron stars or black holes. Even a planet has recently been detected orbiting the pulsating sdB star V391 Peg. Quite to the opposite,in globular clusters, only very few sdB binaries amongst are found indicating that the dominant sdB formation processes is different in a dense environment. Binary population synthesis models identify three formation channels, (i) stable Roche lobe overflow, (ii) one or two common envelope ejection phases and (iii) the merger of two helium white dwarfs. The latter channel may explain the properties of the He-enriched subluminous O stars, the hotter sisters of the sdB stars, because their binary fraction is lower than that of the sdBs by a factor of ten or more. The rivaling ''late hot flasher'' scenario is also discussed. Pulsating subluminous B (sdB) stars play an important role for asteroseismology as this technique has already led to mass determinations for a handful of stars. A unique hyper-velocity sdO star moving so fast that it is unbound to the Galaxy has probably been ejected by the super-massive black hole in the Galactic centre.

  11. 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.

  12. Branch classification: A new mechanism for improving branch predictor performance

    SciTech Connect

    Chang, P.Y.; Hao, E.; Patt, Y.; Yeh, T.Y.

    1996-04-01

    There is wide agreement that one of the most significant impediments to the performance of current and future pipelined superscalar processors is the presence of conditional branches in the instruction stream. Speculative execution is one solution to the branch problem, but speculative work is discarded if a branch is mispredicted. For it to be effective, speculative work is discarded if a branch is mispredicted. For it to be effective, speculative execution requires a very accurate branch predictor; 95% accuracy is not good enough. This paper proposes branch classification, a methodology for building more accurate branch predictors. Branch classification allows an individual branch instruction to be associated with the branch predictor best suited to predict its direction. Using this approach, a hybrid branch predictor can be constructed such that each component branch predictor predicts those branches for which it is best suited. To demonstrate the usefulness of branch classification, an example classification scheme is given and a new hybrid predictor is built based on this scheme which achieves a higher prediction accuracy than any branch predictor previously reported in the literature.

  13. A deoxyribozyme that synthesizes 2′,5′-branched RNA with any branch-site nucleotide

    PubMed Central

    Pratico, Elizabeth D.; Wang, Yangming; Silverman, Scott K.

    2005-01-01

    RNA molecules with internal 2′,5′-branches are intermediates in RNA splicing, and branched RNAs have recently been proposed as retrotransposition intermediates. A broadly applicable in vitro synthetic route to branched RNA that does not require self-splicing introns or spliceosomes would substantially improve our ability to study biochemical processes that involve branched RNA. We recently described 7S11, a deoxyribozyme that was identified by in vitro selection and has general RNA branch-forming ability. However, an important restriction for 7S11 is that the branch-site RNA nucleotide must be a purine (A or G), because a pyrimidine (U or C) is not tolerated. Here, we describe the compact 6CE8 deoxyribozyme (selected using a 20 nt random region) that synthesizes 2′,5′-branched RNA with any nucleotide at the branch site. The Mn2+-dependent branch-forming ligation reaction is between an internal branch-site 2′-hydroxyl nucleophile on one RNA substrate with a 5′-triphosphate on another RNA substrate. The preference for the branch-site nucleotide is U > C ≅ A > G, although all four nucleotides are tolerated with useful ligation rates. Nearly all other nucleotides elsewhere in both RNA substrates allow ligation activity, except that the sequence requirement for the RNA strand with the 5′-triphosphate is 5′-pppGA, with 5′-pppGAR (R = purine) preferred. These characteristics permit 6CE8 to prepare branched RNAs of immediate practical interest, such as the proposed branched intermediate of Ty1 retrotransposition. Because this branched RNA has two strands with identical sequence that emerge from the branch site, we developed strategies to control which of the two strands bind with the deoxyribozyme during the branch-forming reaction. The ability to synthesize the proposed branched RNA of Ty1 retrotransposition will allow us to explore this important biochemical pathway in greater detail. PMID:15967808

  14. 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.

  15. 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.

  16. The branchings of the main s-process: their sensitivity to α-induced reactions on 13C and 22Ne and to the uncertainties of the nuclear network

    NASA Astrophysics Data System (ADS)

    Bisterzo, S.; Gallino, R.; Käppeler, F.; Wiescher, M.; Imbriani, G.; Straniero, O.; Cristallo, S.; Görres, J.; deBoer, R. J.

    2015-05-01

    This paper provides a detailed analysis of the main component of the slow neutron capture process (the s-process), which accounts for the solar abundances of half of the nuclei with 90 ≲ A ≲ 208. We examine the impact of the uncertainties of the two neutron sources operating in low-mass asymptotic giant branch (AGB) stars: the 13C(α, n)16O reaction, which releases neutrons radiatively during interpulse periods (kT ˜ 8 keV), and the 22Ne(α, n)25Mg reaction, partially activated during the convective thermal pulses (TPs). We focus our attention on the branching points that mainly influence the abundance of s-only isotopes. In our AGB models, the 13C is fully consumed radiatively during interpulse. In this case, we find that the present uncertainty associated with the 13C(α, n)16O reaction has marginal effects on s-only nuclei. On the other hand, a reduction of this rate may increase the amount of residual (or unburned) 13C at the end of the interpulse: in this condition, the residual 13C is burned at higher temperature in the convective zone powered by the following TP. The neutron burst produced by the 22Ne(α, n)25Mg reaction has major effects on the branches along the s-path. The contributions of s-only isotopes with 90 ≲ A ≤ 204 are reproduced within solar and nuclear uncertainties, even if the 22Ne(α, n)25Mg rate is varied by a factor of 2. Improved β-decay and neutron capture rates of a few key radioactive nuclides would help to attain a comprehensive understanding of the solar main component.

  17. Atomic branching in molecules

    NASA Astrophysics Data System (ADS)

    Estrada, Ernesto; Rodríguez-Velázquez, Juan A.; Randić, Milan

    A graph theoretic measure of extended atomic branching is defined that accounts for the effects of all atoms in the molecule, giving higher weight to the nearest neighbors. It is based on the counting of all substructures in which an atom takes part in a molecule. We prove a theorem that permits the exact calculation of this measure based on the eigenvalues and eigenvectors of the adjacency matrix of the graph representing a molecule. The definition of this measure within the context of the Hückel molecular orbital (HMO) and its calculation for benzenoid hydrocarbons are also studied. We show that the extended atomic branching can be defined using any real symmetric matrix, as well as any Hermitian (self-adjoint) matrix, which permits its calculation in topological, geometrical, and quantum chemical contexts.

  18. Underwater branch connection study

    SciTech Connect

    Not Available

    1992-06-01

    This report was prepared with the object of developing guidelines for designing underwater connections of branch pipelines to main lines at existing tap valves and with hot taps in diver accessible water depths. The report considers ANSI Classes 600 and 900 branch pipelines of up to twelve inches in diameter that conform to API Specification 5L minimum. Loads due to gravity, buoyancy, intemal and external pressure, thermal expansion, hydrodynamics and random events are considered. External corrosion, temperature, cover, bottom conditions, stability, testing, commissioning, trenching, and pigging are also addressed. A general discussion of these issues is included in the body of the report. Methods of analysis are included in the appendices and in various references. Lotus 123'' spreadsheets that compute the expansion stresses resulting from pressure and temperature at points on a generic piping geometry are presented. A program diskette is included with the report. The report summarizes, and draws from, the results of a survey of the relevant practice and experience of fifteen gas pipeline operating companies. The survey indicates that most existing branch connections do not provide for pigging of the lateral lines, but that there is a growing consensus that cleaning and inspection pigging of lateral lines is desirable or necessary.

  19. Renal branching morphogenesis: morphogenetic and signaling mechanisms.

    PubMed

    Blake, Joshua; Rosenblum, Norman D

    2014-12-01

    The human kidney is composed of an arborized network of collecting ducts, calyces and urinary pelvis that facilitate urine excretion and regulate urine composition. The renal collecting system is formed in utero, completed by the 34th week of gestation in humans, and dictates final nephron complement. The renal collecting system arises from the ureteric bud, a derivative of the intermediate-mesoderm derived nephric duct that responds to inductive signals from adjacent tissues via a process termed ureteric induction. The ureteric bud subsequently undergoes a series of iterative branching and remodeling events in a process called renal branching morphogenesis. Altered signaling that disrupts patterning of the nephric duct, ureteric induction, or renal branching morphogenesis leads to varied malformations of the renal collecting system collectively known as congenital anomalies of the kidney and urinary tract (CAKUT) and is the most frequently detected congenital renal aberration in infants. Here, we describe critical morphogenetic and cellular events that govern nephric duct specification, ureteric bud induction, renal branching morphogenesis, and cessation of renal branching morphogenesis. We also highlight salient molecular signaling pathways that govern these processes, and the investigative techniques used to interrogate them. PMID:25080023

  20. Branching Morphogenesis: From Cells to Organs and Back

    PubMed Central

    Ochoa-Espinosa, Amanda; Affolter, Markus

    2012-01-01

    Many animal organs, such as the lung, the kidney, the mammary gland, and the vasculature, consist of branched tubular structures that arise through a process known as “branching morphogenesis” that results from the remodeling of epithelial or endothelial sheaths into multicellular tubular networks. In recent years, the combination of molecular biology, forward and reverse genetic approaches, and their complementation by live imaging has started to unravel rules and mechanisms controlling branching processes in animals. Common patterns of branch formation spanning diverse model systems are beginning to emerge that might reflect unifying principles of tubular organ formation. PMID:22798543

  1. The role of branch architecture in assimilate production and partitioning: the example of apple (Malus domestica)

    PubMed Central

    Fanwoua, Julienne; Bairam, Emna; Delaire, Mickael; Buck-Sorlin, Gerhard

    2014-01-01

    Understanding the role of branch architecture in carbon production and allocation is essential to gain more insight into the complex process of assimilate partitioning in fruit trees. This mini review reports on the current knowledge of the role of branch architecture in carbohydrate production and partitioning in apple. The first-order carrier branch of apple illustrates the complexity of branch structure emerging from bud activity events and encountered in many fruit trees. Branch architecture influences carbon production by determining leaf exposure to light and by affecting leaf internal characteristics related to leaf photosynthetic capacity. The dynamics of assimilate partitioning between branch organs depends on the stage of development of sources and sinks. The sink strength of various branch organs and their relative positioning on the branch also affect partitioning. Vascular connections between branch organs determine major pathways for branch assimilate transport. We propose directions for employing a modeling approach to further elucidate the role of branch architecture on assimilate partitioning. PMID:25071813

  2. 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.

  3. [Masquerading bundle branch block].

    PubMed

    Kukla, Piotr; Baranchuk, Adrian; Jastrzębski, Marek; Bryniarski, Leszek

    2014-01-01

    We here describe a surface 12-lead electrocardiogram (ECG) of a 72-year-old female with a prior history of breast cancer and chemotherapy-induced cardiomyopathy. An echocardiogram revealed left ventricular dysfunction, ejection fraction of 23%, with mild enlarged left ventricle. The 12-lead ECG showed atrial fibrillation with a mean heart rate of about 100 bpm, QRS duration 160 ms, QT interval 400 ms, right bundle branch block (RBBB) and left anterior fascicular block (LAFB). The combination of RBBB features in the precordial leads and LAFB features in the limb leads is known as ''masquerading bundle branch block''. In most cases of RBBB and LAFB, the QRS axis deviation is located between - 80 to -120 degrees. Rarely, when predominant left ventricular forces are present, the QRS axis deviation is near about -90 degrees, turning the pattern into an atypical form. In a situation of RBBB associated with LAFB, the S wave can be absent or very small in lead I. Such a situation is the result of not only purely LAFB but also with left ventricular hypertrophy and/or focal block due to scar (extensive anterior myocardial infarction) or fibrosis (cardiomyopathy). Sometimes, this specific ECG pattern is mistaken for LBBB. RBBB with LAFB may imitate LBBB either in the limb leads (known as 'standard masquerading' - absence of S wave in lead I), or in the precordial leads (called 'precordial masquerading' - absence of S wave in leads V₅ and V₆). Our ECG showed both these types of masquerading bundle branch block - absence of S wave in lead I and in leads V₅ and V₆. PMID:24469750

  4. 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.

  5. 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.

  6. 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.

  7. Airway branching morphogenesis in three dimensional culture

    PubMed Central

    2010-01-01

    Background Lungs develop from the fetal digestive tract where epithelium invades the vascular rich stroma in a process called branching morphogenesis. In organogenesis, endothelial cells have been shown to be important for morphogenesis and the maintenance of organ structure. The aim of this study was to recapitulate human lung morphogenesis in vitro by establishing a three dimensional (3D) co-culture model where lung epithelial cells were cultured in endothelial-rich stroma. Methods We used a human bronchial epithelial cell line (VA10) recently developed in our laboratory. This cell line cell line maintains a predominant basal cell phenotype, expressing p63 and other basal markers such as cytokeratin-5 and -14. Here, we cultured VA10 with human umbilical vein endothelial cells (HUVECs), to mimic the close interaction between these cell types during lung development. Morphogenesis and differentiation was monitored by phase contrast microscopy, immunostainings and confocal imaging. Results We found that in co-culture with endothelial cells, the VA10 cells generated bronchioalveolar like structures, suggesting that lung epithelial branching is facilitated by the presence of endothelial cells. The VA10 derived epithelial structures display various complex patterns of branching and show partial alveolar type-II differentiation with pro-Surfactant-C expression. The epithelial origin of the branching VA10 colonies was confirmed by immunostaining. These bronchioalveolar-like structures were polarized with respect to integrin expression at the cell-matrix interface. The endothelial-induced branching was mediated by soluble factors. Furthermore, fibroblast growth factor receptor-2 (FGFR-2) and sprouty-2 were expressed at the growing tips of the branching structures and the branching was inhibited by the FGFR-small molecule inhibitor SU5402. Discussion In this study we show that a human lung epithelial cell line can be induced by endothelial cells to form branching

  8. 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.

  9. 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.

  10. Modeling branching in cereals

    PubMed Central

    Evers, Jochem B.; Vos, Jan

    2013-01-01

    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. PMID:24133499

  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. Branching mechanisms in surfactant micelles

    NASA Astrophysics Data System (ADS)

    Dhakal, Subas; Sureshkumar, Radhakrishna

    The mechanisms of branch formation in surfactant micelles of cetyltrimethylammonium chloride (CTAC) in presence of sodium salicylate (NaSal) counter ions in water are studied using molecular dynamics simulations. The curvature energy associated with the formation of micelle branches and the effect of branching on the solution viscosity are quantified. Highly curved surfaces are energetically stabilized by a higher density of binding counter ions near the branch points. Simulations show that micellar branches result in a significant reduction in the solution viscosity as observed in experiments [Dhakal & Sureshkumar, J. Chem. Phys. 143, 024905 (2015)]. This reduction in viscosity has long been attributed to the sliding motion of micelle branches across the main chain. However, to date, such dynamics of micelle branches have never been visualized in either experiments or simulations. Here, we explicitly illustrate and quantify, for the first time, how branches slide along the micelle contour to facilitate stress relaxation. We acknowledged the computational resources provided by XSEDE which is supported by NSF Grant Number OCI-1053575 and the financial support by National Science Foundation under Grants 1049489 and 1049454.

  13. SnapShot: Branching Morphogenesis.

    PubMed

    Chuong, Cheng-Ming; Bhat, Ramray; Widelitz, Randall B; Bissell, Mina J

    2014-08-28

    Ectodermal appendages such as feathers, hair, mammary glands, salivary glands, and sweat glands form branches, allowing much-increased surface for functional differentiation and secretion. Here, the principles of branching morphogenesis are exemplified by the mammary gland and feathers. PMID:25171418

  14. Adsorption of annealed branched polymers on curved surfaces

    NASA Astrophysics Data System (ADS)

    Wagner, Jef; Erdemci-Tandogan, Gonca; Zandi, Roya

    2015-12-01

    The behavior of annealed branched polymers near adsorbing surfaces plays a fundamental role in many biological and industrial processes. Most importantly single stranded RNA in solution tends to fold up and self-bind to form a highly branched structure. Using a mean field theory, we both perturbatively and numerically examine the adsorption of branched polymers on surfaces of several different geometries in a good solvent. Independent of the geometry of the wall, we observe that as branching density increases, surface tension decreases. However, we find a coupling between the branching density and curvature in that a further lowering of surface tension occurs when the wall curves towards the polymer, but the amount of lowering of surface tension decreases when the wall curves away from the polymer. We find that for branched polymers confined into spherical cavities, most of branch-points are located in the vicinity of the interior wall and the surface tension is minimized for a critical cavity radius. For branch polymers next to sinusoidal surfaces, we find that branch-points accumulate at the valleys while end-points on the peaks.

  15. Primary Cilia Regulate Branching Morphogenesis During Mammary Gland Development

    PubMed Central

    McDermott, Kimberly M.; Liu, Bob Y.; Tlsty, Thea D.; Pazour, Gregory J.

    2010-01-01

    Summary During mammary gland development an epithelial bud undergoes branching morphogenesis to expand into a continuous tree-like network of branched ducts [1]. The process involves multiple cell types that are coordinated by hormones and growth factors coupled with signaling events including Wnt and Hedgehog [2-5]. Primary cilia play key roles in the development of many organs by coordinating extracellular signaling (Wnt, Hedgehog) with cellular physiology [6-8]. During mammary development, we find cilia on luminal epithelial, myoepithelial and stromal cells during early branching morphogenesis when epithelial ducts extend into the fat pad and undergo branching morphogenesis. When branching is complete, cilia disappear from luminal epithelial cells but remain on myoepithelial and stromal cells. Ciliary dysfunction caused by intraflagellar transport (IFT) defects results in branching defects. These include decreased ductal extension and decreased secondary and tertiary branching along with reduced lobular-alveolar development during pregnancy and lactation. We find increased canonical Wnt and decreased Hedgehog signaling in the mutant glands, which is consistent with the role of cilia in regulating these pathways [6-11]. In mammary gland and other organs, increased canonical Wnt [12-14] and decreased Hedgehog [15, 16] signaling decreases branching morphogenesis suggesting that Wnt and Hedgehog signaling connect ciliary dysfunction to branching defects. PMID:20381354

  16. 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

  17. 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.

  18. Tension in Highly Branched Polymers

    NASA Astrophysics Data System (ADS)

    Rubinstein, Michael

    2012-02-01

    We propose a systematic method of designing branched macromolecules capable of building up high tension in their covalent bonds, which can be controlled by changing solvent quality. This tension is achieved exclusively due to intramolecular interactions by focusing lower tensions from its numerous branches to a particular section of the designed molecule. The simplest molecular architecture, which allows this tension amplification, is a so-called pom-pom macromolecule consisting of a relatively short linear spacer and two z-arm stars at its ends. Tension developed in the stars due to crowding of their branches is amplified by a factor of z and focused to the spacer. There are other highly branched macromolecules, such as molecular brushes - comb polymers with high density of side branches, that have similar focusing and amplification properties. In addition molecular brushes transmit tension along their backbone. Adsorption or grafting of these branched molecules on a substrate results in further increase in tension as compared to molecules in solution. Molecular architectures similar to pom-pom and molecular brushes with a high tension amplification parts can be used in numerous sensor applications. Unique conformations of molecular brushes in a pre-wetting layer allow direct visualization by atomic force microscope. Detailed images of individual molecules spreading along the surface enable critical evaluation of theories of chain dynamics in polymer monolayer. Strong spreading of densely branched macromolecules on a planar substrate can lead to high tension in the molecular backbone sufficient to break covalent bonds.

  19. 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.

  20. Dynamical Scaling in Branching Models for Seismicity

    SciTech Connect

    Lippiello, Eugenio; Godano, Cataldo; De Arcangelis, Lucilla

    2007-03-02

    We propose a branching process based on a dynamical scaling hypothesis relating time and mass. In the context of earthquake occurrence, we show that experimental power laws in size and time distribution naturally originate solely from this scaling hypothesis. We present a numerical protocol able to generate a synthetic catalog with an arbitrary large number of events. The numerical data reproduce the hierarchical organization in time and magnitude of experimental interevent time distribution.

  1. Discrete self-oscillation period branches observed in semiconductor superlattices

    NASA Astrophysics Data System (ADS)

    Wang, Jun; Hu, Bambi; Zheng, Zhigang; Li, Zhigang

    2011-04-01

    We investigate the self-sustained current oscillation of a weakly coupled semiconductor superlattice in the dynamical voltage band using a microscopic sequential tunneling model. With the voltage as a control parameter, two types of branches of current oscillation period versus voltage have been observed, which correspond to various oscillation scenarios. The first branch type consists of a series of period branches in accordance with how many charge dipoles need to be created at the emitter side to trigger a dipole-tripole oscillation scenario. For the second branch type, charge dipoles are generated periodically at the emitter, but all of them fail to develop completely and die out, thereby leading to a low-period oscillation scenario without the dipole-tripole process. The bistability between different branches is also observed by voltage up-sweeping and down-sweeping.

  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. 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.

  4. 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.

  5. 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 166.4 Commodity and Securities Exchanges COMMODITY FUTURES TRADING COMMISSION CUSTOMER PROTECTION RULES § 166.4 Branch offices. Each branch office of each Commission registrant must use the name of the firm of which it is a branch for all...

  6. 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.

  7. 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. PMID:27039023

  8. 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)

  9. Theoretical horizontal-branch evolution

    NASA Technical Reports Server (NTRS)

    Sweigart, Allen V.

    1987-01-01

    The general features of the theoretical evolution of canonical horizontal-branch (HB) stars are briefly reviewed with specific emphasis on the track morphology in the HR diagram and the determination of the globular cluster helium abundance. The observational evidence for the occurrence of semiconvection is discussed together with some remaining theoretical uncertainty.

  10. 76 FR 13272 - Branch Offices

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-03-10

    ... 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 will... approval number, to Information Collection Comments, Chief Counsel's Office, Office of Thrift...

  11. 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.

  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. Deltoid Branch of Thoracoacromial Vein

    PubMed Central

    Su, Ta-Wei; Wu, Ching-Feng; Fu, Jui-Ying; Ko, Po-Jen; Yu, Sheng-Yueh; Kao, Tsung-Chi; Hsieh, Hong-Chang; Wu, Ching-Yang

    2015-01-01

    Abstract An entry vessel is crucial for intravenous port implantation. A safe alternative entry vessel that can be easily explored is crucial for patients without feasible cephalic vein or for those who need port reimplantation because of disease relapse. In this study, we tried to analyze the safety and feasibility of catheter implantation via the deltoid branch of the thoracoacromial vein. From March 2012 to November 2013, 802 consecutive oncology patients who had received intravenous port implantation via the superior vena cava were enrolled in this study. The functional results and complications of different entry vessels were compared. The majority of patients (93.6%) could be identified as thoracoacromial vessel. The deltoid branch of the thoracoacromial vein is located on the medial aspect of the deltopectoral groove beneath the pectoralis major muscle (85.8%) and in the deep part of the deltopectoral groove (14.2%). Due to the various calibers employed and tortuous routes followed, we utilized 3 different methods for catheter implantation, including vessel cutdown (47.4%), wire assisted (17.9%), and modified puncture method (34.6%). The functional results and complication rate were similar to other entry vessels. The deltoid branch of the thoracoacromial vein is located in the neighborhood of the cephalic vein. The functional results of intravenous port implantation via the deltoid branch of the thoracoacromial vein are similar to other entry vessels. It is a safe alternative entry vessel for intravenous port implantation. PMID:25929903

  14. 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

  15. Regulation of branching dynamics by axon-intrinsic asymmetries in Tyrosine Kinase Receptor signaling

    PubMed Central

    Zschätzsch, Marlen; Oliva, Carlos; Langen, Marion; De Geest, Natalie; Özel, Mehmet Neset; Williamson, W Ryan; Lemon, William C; Soldano, Alessia; Munck, Sebastian; Hiesinger, P Robin; Sanchez-Soriano, Natalia; Hassan, Bassem A

    2014-01-01

    Axonal branching allows a neuron to connect to several targets, increasing neuronal circuit complexity. While axonal branching is well described, the mechanisms that control it remain largely unknown. We find that in the Drosophila CNS branches develop through a process of excessive growth followed by pruning. In vivo high-resolution live imaging of developing brains as well as loss and gain of function experiments show that activation of Epidermal Growth Factor Receptor (EGFR) is necessary for branch dynamics and the final branching pattern. Live imaging also reveals that intrinsic asymmetry in EGFR localization regulates the balance between dynamic and static filopodia. Elimination of signaling asymmetry by either loss or gain of EGFR function results in reduced dynamics leading to excessive branch formation. In summary, we propose that the dynamic process of axon branch development is mediated by differential local distribution of signaling receptors. DOI: http://dx.doi.org/10.7554/eLife.01699.001 PMID:24755286

  16. 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.

  17. 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

  18. Introduction to Asymptotic Giant Branch Stars

    NASA Astrophysics Data System (ADS)

    El Eid, Mounib F.

    2016-04-01

    A brief introduction on the main characteristics of the asymptotic giant branch stars (briefly: AGB) is presented. We describe a link to observations and outline basic features of theoretical modeling of these important evolutionary phases of stars. The most important aspects of the AGB stars is not only because they are the progenitors of white dwarfs, but also they represent the site of almost half of the heavy element formation beyond iron in the galaxy. These elements and their isotopes are produced by the s-process nucleosynthesis, which is a neutron capture process competing with the β- radioactive decay. The neutron source is mainly due to the reaction 13C(α,n)16O reaction. It is still a challenging problem to obtain the right amount of 13 C that can lead to s-process abundances compatible with observation. Some ideas are presented in this context.

  19. 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.

  20. 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.

  1. 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.

  2. Interactions between axillary branches of Arabidopsis.

    PubMed

    Ongaro, Veronica; Bainbridge, Katherine; Williamson, Lisa; Leyser, Ottoline

    2008-03-01

    Studies of apical dominance have benefited greatly from two-branch assays in pea and bean, in which the shoot system is trimmed back to leave only two active cotyledonary axillary branches. In these two-branch shoots, a large body of evidence shows that one actively growing branch is able to inhibit the growth of the other, prompting studies on the nature of the inhibitory signals, which are still poorly understood. Here, we describe the establishment of two-branch assays in Arabidopsis, using consecutive branches on the bolting stem. As with the classical studies in pea and bean, these consecutive branches are able to inhibit one another's growth. Not only can the upper branch inhibit the lower branch, but also the lower branch can inhibit the upper branch, illustrating the bi-directional action of the inhibitory signals. Using mutants, we show that the inhibition is partially dependent on the MAX pathway and that while the inhibition is clearly transmitted across the stem from the active to the inhibited branch, the vascular connectivity of the two branches is weak, and the MAX pathway is capable of acting unilaterally in the stem. PMID:19825548

  3. Electrostatically anchored branched brush layers.

    PubMed

    Liu, Xiaoyan; Dedinaite, Andra; Rutland, Mark; Thormann, Esben; Visnevskij, Ceslav; Makuska, Ricardas; Claesson, Per M

    2012-11-01

    A novel type of block copolymer has been synthesized. It consists of a linear cationic block and an uncharged bottle-brush block. The nonionic bottle-brush block contains 45 units long poly(ethylene oxide) side chains. This polymer was synthesized with the intention of creating branched brush layers firmly physisorbed to negatively charged surfaces via the cationic block, mimicking the architecture (but not the chemistry) of bottle-brush molecules suggested to be present on the cartilage surface, and contributing to the efficient lubrication of synovial joints. The adsorption properties of the diblock copolymer as well as of the two blocks separately were studied on silica surfaces using quartz crystal microbalance with dissipation monitoring (QCM-D) and optical reflectometry. The adsorption kinetics data highlight that the diblock copolymers initially adsorb preferentially parallel to the surface with both the cationic block and the uncharged bottle-brush block in contact with the surface. However, as the adsorption proceeds, a structural change occurs within the layer, and the PEO bottle-brush block extends toward solution, forming a surface-anchored branched brush layer. As the adsorption plateau is reached, the diblock copolymer layer is 46-48 nm thick, and the water content in the layer is above 90 wt %. The combination of strong electrostatic anchoring and highly hydrated branched brush structures provide strong steric repulsion, low friction forces, and high load bearing capacity. The strong electrostatic anchoring also provides high stability of preadsorbed layers under different ionic strength conditions. PMID:23046176

  4. 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

  5. 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. PMID:22181236

  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. 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

  8. Fabrication of Chemically Tunable, Hierarchically Branched Polymeric Nanostructures by Multi-branched Anodic Aluminum Oxide Templates.

    PubMed

    Jo, Hanju; Haberkorn, Niko; Pan, Jia-Ahn; Vakili, Mohammad; Nielsch, Kornelius; Theato, Patrick

    2016-06-28

    In this paper, a template-assisted replication method is demonstrated for the fabrication of hierarchically branched polymeric nanostructures composed of post-modifiable poly(pentafluorophenyl acrylate). Anodic aluminum oxide templates with various shapes of hierarchically branched pores are fabricated by an asymmetric two-step anodization process. The hierarchical polymeric nanostructures are obtained by infiltration of pentafluorophenyl acrylate with a cross-linker and photoinitiator, followed by polymerization and selective removal of the template. Furthermore, the nanostructures containing reactive pentafluorophenyl ester are modified with spiropyran amine via post-polymerization modification to fabricate ultraviolet-responsive nanostructures. This method can be readily extended to other amines and offers a generalized strategy for controlling functionality and wettability of surfaces. PMID:27243550

  9. 30 CFR 56.6403 - Branch circuits.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-SURFACE METAL AND NONMETAL MINES Explosives Electric Blasting § 56.6403 Branch circuits. (a) If electric blasting includes the use of branch circuits,...

  10. 30 CFR 56.6403 - Branch circuits.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-SURFACE METAL AND NONMETAL MINES Explosives Electric Blasting § 56.6403 Branch circuits. (a) If electric blasting includes the use of branch circuits,...

  11. 30 CFR 56.6403 - Branch circuits.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-SURFACE METAL AND NONMETAL MINES Explosives Electric Blasting § 56.6403 Branch circuits. (a) If electric blasting includes the use of branch circuits,...

  12. 30 CFR 56.6403 - Branch circuits.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-SURFACE METAL AND NONMETAL MINES Explosives Electric Blasting § 56.6403 Branch circuits. (a) If electric blasting includes the use of branch circuits,...

  13. 30 CFR 56.6403 - Branch circuits.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-SURFACE METAL AND NONMETAL MINES Explosives Electric Blasting § 56.6403 Branch circuits. (a) If electric blasting includes the use of branch circuits,...

  14. 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.

  15. Do tree split probabilities determine the branch lengths?

    PubMed

    Chor, Benny; Steel, Mike

    2015-06-01

    The evolution of aligned DNA sequence sites is generally modeled by a Markov process operating along the edges of a phylogenetic tree. It is well known that the probability distribution on the site patterns at the tips of the tree determines the tree topology, and its branch lengths. However, the number of patterns is typically much larger than the number of edges, suggesting considerable redundancy in the branch length estimation. In this paper we ask whether the probabilities of just the 'edge-specific' patterns (the ones that correspond to a change of state on a single edge) suffice to recover the branch lengths of the tree, under a symmetric 2-state Markov process. We first show that this holds provided the branch lengths are sufficiently short, by applying the inverse function theorem. We then consider whether this restriction to short branch lengths is necessary. We show that for trees with up to four leaves it can be lifted. This leaves open the interesting question of whether this holds in general. Our results also extend to certain Markov processes on more than 2-states, such as the Jukes-Cantor model. PMID:25843219

  16. 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. PMID:27333567

  17. Tree branch angle: maximizing effective leaf area.

    PubMed

    Honda, H; Fisher, J B

    1978-02-24

    In a computer simulation of branching pattern and leaf cluster in Terminalia catappa, right and left branch angles were varied, and the effective leaf surface areas were calculated. Theoretical branch angles that result in maximum effective leaf area are close to the values observed in nature. PMID:17757590

  18. 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…

  19. Risking Exposure: Branch Campus Writers Go Public.

    ERIC Educational Resources Information Center

    Sitler, Helen Collins

    For students who live and study at a branch campus of a mid-sized state university in southwest Pennsylvania, the 30 miles between them and their parent university represents a geographic gulf. No courier carries mail or deliveries between the main campus and the branches, and as a result, students at the branches have no access to the campus…

  20. 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.

  1. 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…

  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. Cyanogen in NGC 1851 Red Giant Branch and Asymptotic Giant Branch Stars: Quadrimodal Distributions

    NASA Astrophysics Data System (ADS)

    Campbell, S. W.; Yong, D.; Wylie-de Boer, E. C.; Stancliffe, R. J.; Lattanzio, J. C.; Angelou, G. C.; D'Orazi, V.; Martell, S. L.; Grundahl, F.; Sneden, C.

    2012-12-01

    The Galactic globular cluster NGC 1851 has raised much interest since Hubble Space Telescope photometry revealed that it hosts a double subgiant branch. Here we report on our homogeneous study into the cyanogen (CN) band strengths in the red giant branch (RGB) population (17 stars) and asymptotic giant branch (AGB) population (21 stars) using AAOmega/2dF spectra with R ~ 3000. We discover that NGC 1851 hosts a quadrimodal distribution of CN band strengths in its RGB and AGB populations. This result supports the merger formation scenario proposed for this cluster, such that the CN quadrimodality could be explained by the superposition of two "normal" bimodal populations. A small sample overlap with an abundance catalog allowed us to tentatively explore the relationship between our CN populations and a range of elemental abundances. We found a striking correlation between CN and [O/Na]. We also found that the four CN peaks may be paired—the two CN-weaker populations being associated with low Ba and the two CN-stronger populations with high Ba. If true, then s-process abundances would be a good diagnostic for disentangling the two original clusters in the merger scenario. More observations are needed to confirm the quadrimodality and also the relationship between the subpopulations. We also report CN results for NGC 288 as a comparison. Our relatively large samples of AGB stars show that both clusters have a bias toward CN-weak AGB populations.

  4. CYANOGEN IN NGC 1851 RED GIANT BRANCH AND ASYMPTOTIC GIANT BRANCH STARS: QUADRIMODAL DISTRIBUTIONS

    SciTech Connect

    Campbell, S. W.; Stancliffe, R. J.; Lattanzio, J. C.; Angelou, G. C.; D'Orazi, V.; Yong, D.; Wylie-de Boer, E. C.; Martell, S. L.; Grundahl, F.; Sneden, C. E-mail: david.yong@anu.edu.au

    2012-12-10

    The Galactic globular cluster NGC 1851 has raised much interest since Hubble Space Telescope photometry revealed that it hosts a double subgiant branch. Here we report on our homogeneous study into the cyanogen (CN) band strengths in the red giant branch (RGB) population (17 stars) and asymptotic giant branch (AGB) population (21 stars) using AAOmega/2dF spectra with R {approx} 3000. We discover that NGC 1851 hosts a quadrimodal distribution of CN band strengths in its RGB and AGB populations. This result supports the merger formation scenario proposed for this cluster, such that the CN quadrimodality could be explained by the superposition of two 'normal' bimodal populations. A small sample overlap with an abundance catalog allowed us to tentatively explore the relationship between our CN populations and a range of elemental abundances. We found a striking correlation between CN and [O/Na]. We also found that the four CN peaks may be paired-the two CN-weaker populations being associated with low Ba and the two CN-stronger populations with high Ba. If true, then s-process abundances would be a good diagnostic for disentangling the two original clusters in the merger scenario. More observations are needed to confirm the quadrimodality and also the relationship between the subpopulations. We also report CN results for NGC 288 as a comparison. Our relatively large samples of AGB stars show that both clusters have a bias toward CN-weak AGB populations.

  5. Synthesis and Characterization of Branched Poly(ester urea)s with Different Branch Density

    NASA Astrophysics Data System (ADS)

    Yu, Jiayi; Becker, Matthew

    2015-03-01

    A new class of L-phenylalanine-based poly(ester urea)s (PEU) was developed that possess tunable mechanical properties, water uptake ability and degradation rates. Our preliminary data has shown that 1,6-hexanediol L - phenylalanine-based poly(ester urea)s possesses an elastic modulus nearly double that of poly(lactic acid). My work details the synthesis of a series of L - phenylalanine-based poly(ester urea)s possessing a variation in diol chain length and in branch density and shows how these subtle structural differences influence the mechanical properties and in vitro biodegradation rates. The elastic moduli span a range of values that overlap with several currently clinically available degradable polymers. Increasingly the diol chain lengths increases the amount of flexible segment in the chemical structure, which results in reduced elastic modulus values and increased values of elongation at break. Increasing the amount of branch monomer incorporated into the system reduces the molecular entanglement, which also results in decreased elastic modulus values and increased values of elongation at break. The L - phenylalanine-based poly(ester urea)s also exhibited a diol length dependent degradation process that varied between 1-5 % over 16 weeks. Compared with PLLA, PEUs degrade more quickly and the rate can be tuned by changing the diol chain length. PEUs absorb more water and the water uptake ability can be tuned by changing the branch density. This work was supported by Akron Functional Materials Center.

  6. 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

  7. Buckling of Branched Cytoskeletal Filaments

    NASA Astrophysics Data System (ADS)

    Quint, D. A.; Schwarz, J. M.

    2011-03-01

    In vitro experiments of growing dendritic actin networks demonstrate reversible stress-softening at high loads, above some critical load. The transition to the stress-softening regime has been attributed to the elastic buckling of individual actin filaments. To estimate the critical load above which softening should occur, we extend the elastic theory of buckling of individual filaments embedded in a network to include the buckling of branched filaments, a signature trait of growing dendritic actin networks. Under certain assumptions, there will be approximately a seven-fold increase in the classical critical bucking load, when compared to the unbranched filament, which is entirely due to the presence of a branch. Moreover, we go beyond the classical buckling regime to investigate the effect of entropic fluctuations. The result of compressing the filament in this case leads to an increase in these fluctuations and eventually the harmonic approximation breaks down signifying the onset of the buckling transition. We compute corrections to the classical critical buckling load near this breakdown.

  8. Vinylogous chain branching catalysed by a dedicated polyketide synthase module.

    PubMed

    Bretschneider, Tom; Heim, Joel B; Heine, Daniel; Winkler, Robert; Busch, Benjamin; Kusebauch, Björn; Stehle, Thilo; Zocher, Georg; Hertweck, Christian

    2013-10-01

    Bacteria use modular polyketide synthases (PKSs) to assemble complex polyketides, many of which are leads for the development of clinical drugs, in particular anti-infectives and anti-tumoral agents. Because these multifarious compounds are notoriously difficult to synthesize, they are usually produced by microbial fermentation. During the past two decades, an impressive body of knowledge on modular PKSs has been gathered that not only provides detailed insight into the biosynthetic pathways but also allows the rational engineering of enzymatic processing lines to yield structural analogues. Notably, a hallmark of all PKS modules studied so far is the head-to-tail fusion of acyl and malonyl building blocks, which leads to linear backbones. Yet, structural diversity is limited by this uniform assembly mode. Here we demonstrate a new type of PKS module from the endofungal bacterium Burkholderia rhizoxinica that catalyses a Michael-type acetyl addition to generate a branch in the carbon chain. In vitro reconstitution of the entire PKS module, X-ray structures of a ketosynthase-branching didomain and mutagenesis experiments revealed a crucial role of the ketosynthase domain in branching the carbon chain. We present a trapped intermediary state in which acyl carrier protein and ketosynthase are covalently linked by the branched polyketide and suggest a new mechanism for chain alkylation, which is functionally distinct from terpenoid-like β-branching. For the rice seedling blight toxin rhizoxin, one of the strongest known anti-mitotic agents, the non-canonical polyketide modification is indispensable for phytotoxic and anti-tumoral activities. We propose that the formation of related pharmacophoric groups follows the same general scheme and infer a unifying vinylogous branching reaction for PKS modules with a ketosynthase-branching-acyl-carrier-protein architecture. This study unveils the structure and function of a new PKS module that broadens the biosynthetic scope of

  9. 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.

  10. Fabrication and spectroscopic investigation of branched silver nanowires and nanomeshworks

    PubMed Central

    2012-01-01

    Wide wavelength ranges of light localization and scattering characteristics can be attributed to shape-dependent longitude surface plasmon resonance in complicated nanostructures. We have studied this phenomenon by spectroscopic measurement and a three-dimensional numerical simulation, for the first time, on the high-density branched silver nanowires and nanomeshworks at room temperature. These nanostructures were fabricated with simple light-induced colloidal method. In the range from the visible to the near-infrared wavelengths, light has been found effectively trapped in those trapping sites which were randomly distributed at the corners, the branches, and the junctions of the nanostructures in those nanostructures in three dimensions. The broadened bandwidth electromagnetic field enhancement property makes these branched nanostructures useful in optical processing and photovoltaic applications. PMID:23101991

  11. How learn the branching ratio

    NASA Astrophysics Data System (ADS)

    Achasov, N. N.; Rogozina, E. V.

    2014-10-01

    Enfant terrible of charmonium spectroscopy, the resonance X(3872), generated a stream of interpretations and ushered in a new exotic XYZ spectroscopy. In the meantime, many (if not all) characteristics of X(3872) are rather ambiguous. We construct spectra of decays of the resonance X(3872) with good analytical and unitary properties which allows to define the branching ratio of the decay studying only one more decay, for example, the X(3872) → π+π- J/ψ(1 S) decay. We next define the range of values of the coupling constant of the X(3872) resonance with the system. Finally, we show that our spectra are effective means of selection of models for the resonance X(3872).

  12. 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

  13. 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.

  14. 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.

  15. 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.

  16. 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

  17. Branched Chain Amino Acid Metabolism in the Biosynthesis of Lycopersicon pennellii Glucose Esters 1

    PubMed Central

    Walters, Donald S.; Steffens, John C.

    1990-01-01

    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 C4 and C5 acids, and branched and straight chain C10, C11, and C12 acids. The structure of the branched acyl constituents suggests that the branched chain amino acid biosynthetic pathway participates in their biosynthesis. [14C]Valine and deuterated branched chain amino acids (and their oxo-acid derivatives) were incorporated into branched C4 and C5 acid groups of glucose esters by a process of transamination, oxidative decarboxylation and subsequent acylation. C4 and C5 branched acids were elongated by two carbon units to produce the branched C10-C12 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. PMID:16667654

  18. Single Molecule Dynamics of Branched DNA Polymers

    NASA Astrophysics Data System (ADS)

    Mai, Danielle; Sing, Charles; Schroeder, Charles

    This work focuses on extending the field of single polymer dynamics to topologically complex polymers. Here, we report the direct observation of DNA-based branched polymers. Recently, we recently demonstrated a two-step synthesis method to generate star, H-shaped, and comb polymers for single molecule visualization. Following synthesis, we use single-color or dual-color single molecule fluorescence microscopy to directly visualize branched polymer dynamics in flow, in particular tracking side branches and backbones independently. In this way, our imaging method allows for characterization of molecular properties, including quantification of polymer contour length and branch distributions. Moving beyond characterization, we use molecular rheology and single molecule techniques to study the dynamics of single branched polymers in flow. Here, we utilize precision microfluidics to directly observe branched DNA polymer conformations during transient stretching, steady-state extension, and relaxation from high stretch. We specifically measure backbone end-to-end distance as a function of time. Experiments and Brownian dynamics simulations show that branched polymer relaxation is a strong function of the number of branches and position of branch points along the main chain backbone.

  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. PMID:20420411

  20. 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.

  1. 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.

  2. 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. PMID:26453026

  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. Optimal branching designs in respiratory systems

    NASA Astrophysics Data System (ADS)

    Park, Keunhwan; Kim, Wonjung; Kim, Ho-Young

    2015-11-01

    In nature, the size of the flow channels systematically decreases with multiple generations of branching, and a mother branch is ultimately divided into numerous terminal daughters. One important feature of branching designs is an increase in the total cross-sectional area along with generation, which provide more time and area for mass transfer at the terminal branches. However, the expansion of the total cross-sectional area can be costly due to the maintenance of redundant branches or the additional viscous resistance. Accordingly, we expect to find optimal designs in natural branching systems. Here we present two examples of branching designs in respiratory systems: fish gills and human lung airways. Fish gills consist of filaments with well-ordered lamellar structures. By developing a mathematical model of oxygen transfer rate as a function of the dimensions of fish gills, we demonstrate that the interlamellar distance has been optimized to maximize the oxygen transfer rate. Using the same framework, we examine the diameter reduction ratio in human lung airways, which branch by dichotomy with a systematic reduction of their diameters. Our mathematical model for oxygen transport in the airways enables us to unveil the design principle of human lung airways.

  5. 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...

  6. 12 CFR 741.11 - Foreign branching.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...) Contents of Business Plan. The written business plan must address the following: (1) Analysis of market... regarding the branch (shares, lending, capital, charge-offs, collections); (6) The field of membership or... for branch operations (balance sheet and income and expense projections) for the first and second...

  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 were sweeping…

  8. 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

  9. 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

  10. 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

  11. 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. PMID:23801487

  12. 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.

  13. [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. PMID:25648003

  14. 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.

  15. Anatomy of the portal branches and the hepatic veins in the caudate lobe of the liver.

    PubMed

    Ortale, J R; Borges Keiralla, L C

    2004-10-01

    The objective of this study was to analyze the caudate portal branches and their relationships with the hepatic caudate veins and propose a new nomenclature for the caudate branches based on their territory of distribution. We realized the fine dissection of the veins of the caudate lobe in 40 human livers fixed and preserved in formalin. In 15/40 (37.5%) cases there was a single branch to the caudate lobe. In 25/40 (62.5%) cases there was more than one branch, with a posterior caudate branch in 20/40 (50%) cases, an anterior caudate branch in 15/40 (37.5%) cases, a left caudate branch in 14/40 (35%) cases, and a right caudate branch in 8/40 (20%) cases. The most frequent combination detected (11/40, 27.5% of cases) was that of the posterior and anterior branches. The venous drainage of the caudate lobe and its papillary process was provided by the superior caudate hepatic vein in 23/40 (57.5%) cases, by the middle caudate vein in 35/40 (87.5%) cases (which was the only vein in 12/35 cases), and by the inferior caudate vein in 16/40 (40%) cases. In 11/40 (12.5%) cases there were accessory caudate veins, which emptied into the left and intermediate hepatic veins. The portal branches and the hepatic veins related to the caudate process were studied. In conclusion, the new nomenclature analyzes more precisely the distribution of the caudate portal branches. PMID:15300411

  16. 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

  17. Branching patterns emerge in a mathematical model of the dynamics of lung development

    PubMed Central

    Guo, Yina; Chen, Ting-Hsuan; Zeng, Xingjuan; Warburton, David; Boström, Kristina I; Ho, Chih-Ming; Zhao, Xin; Garfinkel, Alan

    2014-01-01

    phenomena, and how the system can switch from one branching pattern to another using low-dimensional ‘control knobs’. The model provides a number of testable predictions, some of which have already been observed (though not explained) in experimental work. Key points The development of the lung is a highly stereotypical process, including the structured deployment of three distinct modes of branching: first side branching and then tip splitting with and without 90° rotation of the branching plane. These modes are supposedly under genetic control, but it is not clear how genes could act to produce these spatial patterns. Here, we show that cascades of branching events emerge naturally; the branching cascade can be explained by a relatively simple mathematical model, whose equations model the reaction and diffusion of chemical morphogens. Our low-dimensional model gives a qualitative understanding of how generic physiological mechanisms can produce branching phenomena, and how the system can switch from one branching pattern to another using low-dimensional ‘control knobs’. The model makes a number of experimental predictions, and explains several phenomena that have been observed but whose mechanisms were unknown. PMID:24247979

  18. 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

  19. Roles for auxin, cytokinin, and strigolactone in regulating shoot branching.

    PubMed

    Ferguson, Brett J; Beveridge, Christine A

    2009-04-01

    Many processes have been described in the control of shoot branching. Apical dominance is defined as the control exerted by the shoot tip on the outgrowth of axillary buds, whereas correlative inhibition includes the suppression of growth by other growing buds or shoots. The level, signaling, and/or flow of the plant hormone auxin in stems and buds is thought to be involved in these processes. In addition, RAMOSUS (RMS) branching genes in pea (Pisum sativum) control the synthesis and perception of a long-distance inhibitory branching signal produced in the stem and roots, a strigolactone or product. Auxin treatment affects the expression of RMS genes, but it is unclear whether the RMS network can regulate branching independently of auxin. Here, we explore whether apical dominance and correlative inhibition show independent or additive effects in rms mutant plants. Bud outgrowth and branch lengths are enhanced in decapitated and stem-girdled rms mutants compared with intact control plants. This may relate to an RMS-independent induction of axillary bud outgrowth by these treatments. Correlative inhibition was also apparent in rms mutant plants, again indicating an RMS-independent component. Treatments giving reductions in RMS1 and RMS5 gene expression, auxin transport, and auxin level in the main stem were not always sufficient to promote bud outgrowth. We suggest that this may relate to a failure to induce the expression of cytokinin biosynthesis genes, which always correlated with bud outgrowth in our treatments. We present a new model that accounts for apical dominance, correlative inhibition, RMS gene action, and auxin and cytokinin and their interactions in controlling the progression of buds through different control points from dormancy to sustained growth. PMID:19218361

  20. [Croatian Medical Association--Branch Zagreb].

    PubMed

    Kaić, Zvonimir; Sain, Snjezana; Gulić, Mirjana; Mahovlić, Vjekoslav; Krznarić, Zeljko

    2014-01-01

    The available literature shows us that "Druztvo ljeciteljah u Zagrebus (the Society of Healers in Zagreb) was founded as far back as the year 1845 by a total of thirteen members. This data allows us to follow the role of doctors and health workers in Zagreb through their everyday profession, research, organizational and social work as well as management through a period of over one hundred to seventy years. The Branch Zagreb was active before the official establishment of subsidiaries of CMA which is evident from the minutes of the regular annual assembly of the Croatian Medical Association on 21 March 1948. Until the end of 1956, there was no clear division of labor, functions and competencies between the Branch and the Main Board. Their actions were instead consolidated and the Branch operated within and under the name of Croatian Medical Association. In that year the Branch became independent. The Branch Zagreb is the largest and one of the most active branches of the Croatian Medical Association. At the moment, the Branch brings together 3621 members, regular members--doctors of medicine (2497), doctors of dental medicine (384), retired physicians (710), and associate members (30 specialists with higher education who are not doctors). The Branch is especially accomplished in its activities in the area of professional development of its members and therefore organizes a series of scientific conferences in the framework of continuous education of physicians, allowing its members to acquire necessary points for the extension of their operating license. The choir "Zagrebacki lijecnici pjevaci" (Zagreb Physicians' Choir) of the Croatian Medical Music Society of the CMA and its activities are inseparable from the Branch Zagreb. The Branch is firmly linked to the parent body, the CMA, and thus has a visible impact on the strategy and the activities of the Association as a whole. Most professional societies of the CMA have their headquarters in Zagreb and this is

  1. 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.

  2. 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. PMID:12495920

  3. Relaxation dynamics of branched polymers

    NASA Astrophysics Data System (ADS)

    Ghosh, Arnav

    The Rouse model for star polymers was successfully derived by solving the differential equations governing the net force acting on each bead in a star polymer chain. As opposed to a linear polymer, where we have N unique roots for N beads, in the case of star polymers, there are only 2 Na+1 unique roots and all odd unique roots (except the last root corresponding to the branch point) starting with the first root have a multiplicity of f-1. The relaxation time of the pth unique Rouse mode of a star polymer varies as (2Na + 1)2/p2. Since alternate Rouse modes in a star polymer have a multiplicity of f-1, they add to the terminal modulus of the star polymers and the terminal modulus, G(tau) ends up being proportional to f-1 (besides being inversely proportional to N, which is also the case with linear polymers). A self-consistent theory for the relaxation of entangled star polymers was developed based on the work done by Colby and Rubinstein on linear blends. This theory considers the duality of relaxation dynamics (direct stress relaxation and indirect relaxation by release of constraints) and models the relaxation due to constraint release R(t) based on Dean's approach in solving the vibration frequencies of glassy chains with random spring constants. In our case, the mobilities of beads were considered to be random and based on the relative weight of the prefactor of a Maxwell function, a group of which was fitted to the stress relaxation function mu(t) of a star polymer (proposed and derived by Doi). The tube dilation model for star and comb polymers was investigated in detail and predictions compared to rheological data from polypropylene, polybutadiene and polystyrene comb polymers along with PEP star polymers. The relaxation time from the Tube Dilation Model was compared with the classical Tube Model and was shown to have an extra power dependence on the fraction of the comb backbone.

  4. New branch of Kaluza-Klein compactification

    SciTech Connect

    Kinoshita, Shunichiro

    2007-12-15

    We found a new branch of solutions in Freund-Rubin type flux compactifications. The geometry of these solutions is described as the external space which has a de Sitter symmetry and the internal space which is topologically spherical. However, it is not a simple form of dS{sub p}xS{sup q} but a warped product of de Sitter space and a deformed sphere. We explicitly constructed numerical solutions for a specific case with p=4 and q=4. We show that the new branch of solutions emanates from the marginally stable solution in the branch of dS{sub 4}xS{sup 4} solutions.

  5. Cellular and physical mechanisms of branching morphogenesis

    PubMed Central

    Varner, Victor D.; Nelson, Celeste M.

    2014-01-01

    Branching morphogenesis is the developmental program that builds the ramified epithelial trees of various organs, including the airways of the lung, the collecting ducts of the kidney, and the ducts of the mammary and salivary glands. Even though the final geometries of epithelial trees are distinct, the molecular signaling pathways that control branching morphogenesis appear to be conserved across organs and species. However, despite this molecular homology, recent advances in cell lineage analysis and real-time imaging have uncovered surprising differences in the mechanisms that build these diverse tissues. Here, we review these studies and discuss the cellular and physical mechanisms that can contribute to branching morphogenesis. PMID:25005470

  6. 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. PMID:24345551

  7. Kinesin superfamily protein 2A (KIF2A) functions in suppression of collateral branch extension.

    PubMed

    Homma, Noriko; Takei, Yosuke; Tanaka, Yosuke; Nakata, Takao; Terada, Sumio; Kikkawa, Masahide; Noda, Yasuko; Hirokawa, Nobutaka

    2003-07-25

    Through interactions with microtubules, the kinesin superfamily of proteins (KIFs) could have multiple roles in neuronal function and development. During neuronal development, postmitotic neurons develop primary axons extending toward targets, while other collateral branches remain short. Although the process of collateral branching is important for correct wiring of the brain, the mechanisms involved are not well understood. In this study, we analyzed kif2a(-/-) mice, whose brains showed multiple phenotypes, including aberrant axonal branching due to overextension of collateral branches. In kif2a(-/-) growth cones, microtubule-depolymerizing activity decreased. Moreover, many individual microtubules showed abnormal behavior at the kif2a(-/-) cell edge. Based on these results, we propose that KIF2A regulates microtubule dynamics at the growth cone edge by depolymerizing microtubules and that it plays an important role in the suppression of collateral branch extension. PMID:12887924

  8. 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.

  9. [Croatian Medical Association--Branch Zadar].

    PubMed

    Maštrović, Zelimir

    2014-01-01

    Croatian Medical Association--Branch Zadar was founded on 11 October 1947. During the war time in Croatia doctors and local medical community took tremendous part in organizing health care system. PMID:25648014

  10. 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.

  11. 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.

  12. 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.

  13. 30 CFR 57.6403 - Branch circuits.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-UNDERGROUND METAL AND NONMETAL MINES Explosives Electric Blasting-Surface and Underground § 57.6403 Branch circuits. (a) If electric blasting includes the use...

  14. 30 CFR 57.6403 - Branch circuits.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-UNDERGROUND METAL AND NONMETAL MINES Explosives Electric Blasting-Surface and Underground § 57.6403 Branch circuits. (a) If electric blasting includes the use...

  15. 30 CFR 57.6403 - Branch circuits.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-UNDERGROUND METAL AND NONMETAL MINES Explosives Electric Blasting-Surface and Underground § 57.6403 Branch circuits. (a) If electric blasting includes the use...

  16. 30 CFR 57.6403 - Branch circuits.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-UNDERGROUND METAL AND NONMETAL MINES Explosives Electric Blasting-Surface and Underground § 57.6403 Branch circuits. (a) If electric blasting includes the use...

  17. 30 CFR 57.6403 - Branch circuits.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-UNDERGROUND METAL AND NONMETAL MINES Explosives Electric Blasting-Surface and Underground § 57.6403 Branch circuits. (a) If electric blasting includes the use...

  18. 12 CFR 741.11 - Foreign branching.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... evidencing written permission from the host country to establish the branch that explicitly recognizes NCUA's... the account agreement, at a U.S. office of the credit union. If the host country requires...

  19. [Croatian Medical Association--Branch Sibenik].

    PubMed

    Mihovilcević, Danći

    2014-01-01

    Since the opening of the newly built Sibenik hospital on June 29, 1883, the physicians had the need for association in a free organization where they could solve the problems of medical profession and strive for the development of modern medicine. On December 15, 1939, physicians from Sibenik joined the Croatian Medical Association as the Sibenik branch. Activities of the branch were renewed after the Second World War by the arrivial of new physicians. The branch was founded in 1946, and Dr. Baldo Politeo was elected its president. In 1989 the research unit was founded,and in 2001 for the first time in the history of the Association telepresentation of a book was performed. Since its founding the members of our branch have stood out with their professional, scientific and humanitarian work for which many got deserved acknowledgment from their colleagues, CMA and the town. PMID:25648011

  20. 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

  1. Fiber-Optic Communication Technology Branching Devices

    NASA Astrophysics Data System (ADS)

    Williams, J. C.

    1985-02-01

    This tutorial review of fiber-optic branching devices covers example uses of branching devices, device types, device-performance characteristics, examples of current technology, and system-design methodology. The discussion is limited to passive single- and multimode devices fabricated from optical fibers or graded-index components. Integrated-optic, wavelength-division-multiplexing, and polarization-selective devices are not specifically addressed.

  2. Branched dart leaders preceding lightning return strokes

    NASA Astrophysics Data System (ADS)

    Stolzenburg, Maribeth; Marshall, Thomas C.; Karunarathne, Sumedhe; Karunarathna, Nadeeka; Orville, Richard E.

    2014-04-01

    This study describes the occurrence of branches in lightning dart leaders, based on data acquired in Florida using a high-speed video camera and electric field change sensors. More than half (57%) of 72 flashes with analyzable dart leaders show at least one successful branched dart leader (BDL), and nine flashes have two successful BDLs. Overall, 18% of 282 visible successful dart leaders are branched. Most (42 of 50) cases of BDLs occur in the first dart leader after a stepped leader/return stroke sequence, and the data indicate that 55% of first dart leaders are visibly branched. Compared to first dart leaders in the 31 flashes without any branched dart leaders, BDLs tend to follow stepped leader/return strokes with significantly larger average peak currents (-31.3 versus -20.6 kA) and shorter average interstroke intervals (71.94 versus 94.64 ms). Average peak current of BDL strokes is 62% larger (-17.8 versus -11 kA) than that for unbranched first dart leader strokes. Branched dart leaders generally travel in the some of the most recently used lightning channels, but they are not always within the main channel of the prior return stroke. Successful BDLs may dart all the way to ground when in a prior stroke channel, or they may become stepped leaders when they reach the lower end of the prior stroke branch. Electric field change data for all the BDL cases exhibit an erratic pulse character for at least part of the leader duration; in some cases, the erratic character ends when the branches vanish.

  3. Fast growth of branched nickel monosilicide nanowires by laser-assisted chemical vapor deposition.

    PubMed

    Gao, Y; Zhou, Y S; Qian, M; Xie, Z Q; Xiong, W; Luo, H F; Jiang, L; Lu, Y F

    2011-06-10

    Branched nickel monosilicide (NiSi) nanowires (NWs), for the first time, have been synthesized on Ni foams by laser-assisted chemical vapor deposition using disilane precursor molecules. Studies indicate that 600 °C is the threshold temperature for the growth of a large number of branched NiSi NWs with 100-500 nm long branches extending from the main stems. Below the threshold temperature, unbranched NiSi NWs were obtained. The density of the branched NiSi NWs is relatively higher in comparison to that of the unbranched ones. The growth rate of the branched NiSi NWs at 700 °C is estimated up to 10 µm min(-1). High-resolution transmission electron microscopy and energy-dispersive x-ray spectroscopy of the branched NiSi NWs suggest that the formation of these branched nanostructures is ascribed to the Ni-dominant diffusion process. These NiSi NWs with branched nanostructures could bring them new opportunities in nanodevices. PMID:21474870

  4. Fast growth of branched nickel monosilicide nanowires by laser-assisted chemical vapor deposition

    NASA Astrophysics Data System (ADS)

    Gao, Y.; Zhou, Y. S.; Qian, M.; Xie, Z. Q.; Xiong, W.; Luo, H. F.; Jiang, L.; Lu, Y. F.

    2011-06-01

    Branched nickel monosilicide (NiSi) nanowires (NWs), for the first time, have been synthesized on Ni foams by laser-assisted chemical vapor deposition using disilane precursor molecules. Studies indicate that 600 °C is the threshold temperature for the growth of a large number of branched NiSi NWs with 100-500 nm long branches extending from the main stems. Below the threshold temperature, unbranched NiSi NWs were obtained. The density of the branched NiSi NWs is relatively higher in comparison to that of the unbranched ones. The growth rate of the branched NiSi NWs at 700 °C is estimated up to 10 µm min - 1. High-resolution transmission electron microscopy and energy-dispersive x-ray spectroscopy of the branched NiSi NWs suggest that the formation of these branched nanostructures is ascribed to the Ni-dominant diffusion process. These NiSi NWs with branched nanostructures could bring them new opportunities in nanodevices.

  5. 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

  6. 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

  7. Branch management: mechanisms of axon branching in the developing vertebrate CNS

    PubMed Central

    Kalil, Katherine; Dent, Erik W.

    2014-01-01

    The remarkable ability of a single axon to extend multiple branches and form terminal arbors allows vertebrate neurons to integrate information from divergent regions of the nervous system. Axons select appropriate pathways during development, but it is the branches that extend interstitially from the axon shaft and arborize at specific targets that are responsible for virtually all of the synaptic connectivity in the vertebrate CNS. How do axons form branches at specific target regions? Recent studies have identified molecular cues that activate intracellular signalling pathways in axons and mediate dynamic reorganization of the cytoskeleton to promote the formation of axon branches. PMID:24356070

  8. 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

  9. 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

  10. 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).