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Sample records for preferential attachment dynamics

  1. Growth fluctuation in preferential attachment dynamics

    NASA Astrophysics Data System (ADS)

    Hashimoto, Yasuhiro

    2016-04-01

    In the Yule-Simon process, creation and selection of words follows the preferential attachment mechanism, resulting in a power-law growth in the cumulative number of individual word occurrences as well as the power-law population distribution of the vocabulary. This is derived using mean-field approximation, assuming a continuum limit of both the time and number of word occurrences. However, time and word occurrences are inherently discrete in the process, and it is natural to assume that the cumulative number of word occurrences has a certain fluctuation around the average behavior predicted by the mean-field approximation. We derive the exact and approximate forms of the probability distribution of such fluctuation analytically, and confirm that those probability distributions are well supported by the numerical experiments.

  2. Preferential attachment and growth dynamics in complex systems

    NASA Astrophysics Data System (ADS)

    Yamasaki, Kazuko; Matia, Kaushik; Buldyrev, Sergey V.; Fu, Dongfeng; Pammolli, Fabio; Riccaboni, Massimo; Stanley, H. Eugene

    2006-09-01

    Complex systems can be characterized by classes of equivalency of their elements defined according to system specific rules. We propose a generalized preferential attachment model to describe the class size distribution. The model postulates preferential growth of the existing classes and the steady influx of new classes. According to the model, the distribution changes from a pure exponential form for zero influx of new classes to a power law with an exponential cut-off form when the influx of new classes is substantial. Predictions of the model are tested through the analysis of a unique industrial database, which covers both elementary units (products) and classes (markets, firms) in a given industry (pharmaceuticals), covering the entire size distribution. The model’s predictions are in good agreement with the data. The paper sheds light on the emergence of the exponent τ≈2 observed as a universal feature of many biological, social and economic problems.

  3. Preferential attachment in randomly grown networks

    NASA Astrophysics Data System (ADS)

    Weaver, Iain S.

    2015-12-01

    We reintroduce the model of Callaway et al. (2001) as a special case of a more general model for random network growth. Vertices are added to the graph at a rate of 1, while edges are introduced at rate δ. Rather than edges being introduced at random, we allow for a degree of preferential attachment with a linear attachment kernel, parametrised by m. The original model is recovered in the limit of no preferential attachment, m → ∞. As expected, even weak preferential attachment introduces a power-law tail to the degree distribution. Additionally, this generalisation retains a great deal of the tractability of the original along with a surprising range of behaviour, although key mathematical features are modified for finite m. In particular, the critical edge density, δc which marks the onset of a giant network component is reduced with increasing tendency for preferential attachment. The positive degree-degree correlation introduced by the unbiased growth process is offset by the skewed degree distribution, reducing the network assortativity.

  4. Preferential attachment in multiple trade networks

    NASA Astrophysics Data System (ADS)

    Foschi, Rachele; Riccaboni, Massimo; Schiavo, Stefano

    2014-08-01

    In this paper we develop a model for the evolution of multiple networks which is able to replicate the concentrated and sparse nature of world trade data. Our model is an extension of the preferential attachment growth model to the case of multiple networks. Countries trade a variety of goods of different complexity. Every country progressively evolves from trading less sophisticated to high-tech goods. The probabilities of capturing more trade opportunities at a given level of complexity and of starting to trade more complex goods are both proportional to the number of existing trade links. We provide a set of theoretical predictions and simulative results. A calibration exercise shows that our model replicates the same concentration level of world trade as well as the sparsity pattern of the trade matrix. We also discuss a set of numerical solutions to deal with large multiple networks.

  5. Emergence of global preferential attachment from local interaction

    NASA Astrophysics Data System (ADS)

    Li, Menghui; Gao, Liang; Fan, Ying; Wu, Jinshan; Di, Zengru

    2010-04-01

    Global degree/strength-based preferential attachment is widely used as an evolution mechanism of networks. But it is hard to believe that any individual can get global information and shape the network architecture based on it. In this paper, it is found that the global preferential attachment emerges from the local interaction models, including the distance-dependent preferential attachment (DDPA) evolving model of weighted networks (Li et al 2006 New J. Phys. 8 72), the acquaintance network model (Davidsen et al 2002 Phys. Rev. Lett. 88 128701) and the connecting nearest-neighbor (CNN) model (Vázquez 2003 Phys. Rev. E 67 056104). For the DDPA model and the CNN model, the attachment rate depends linearly on the degree or vertex strength, whereas for the acquaintance network model, the dependence follows a sublinear power law. It implies that for the evolution of social networks, local contact could be more fundamental than the presumed global preferential attachment.

  6. Duality between preferential attachment and static networks on hyperbolic spaces

    NASA Astrophysics Data System (ADS)

    Ferretti, L.; Cortelezzi, M.; Mamino, M.

    2014-02-01

    There is a complex relation between the mechanism of preferential attachment, scale-free degree distributions and hyperbolicity in complex networks. In fact, both preferential attachment and hidden hyperbolic spaces often generate scale-free networks. We show that there is actually a duality between a class of growing spatial networks based on preferential attachment on the sphere and a class of static random networks on the hyperbolic plane. Both classes of networks have the same scale-free degree distribution as the Barabasi-Albert model. As a limit of this correspondence, the Barabasi-Albert model is equivalent to a static random network on an hyperbolic space with infinite curvature.

  7. Link prediction based on local information considering preferential attachment

    NASA Astrophysics Data System (ADS)

    Zeng, Shan

    2016-02-01

    Link prediction in complex networks has attracted much attention in many fields. In this paper, a common neighbors plus preferential attachment index is presented to estimate the likelihood of the existence of a link between two nodes based on local information of the nearest neighbors. Numerical experiments on six real networks demonstrated the high effectiveness and efficiency of the new index compared with five well-known and widely accepted indices: the common neighbors, resource allocation index, preferential attachment index, local path index and Katz index. The new index provides competitively accurate prediction with local path index and Katz index while has less computational complexity and is more accurate than the other two indices.

  8. Emergence of Soft Communities from Geometric Preferential Attachment

    NASA Astrophysics Data System (ADS)

    Zuev, Konstantin; Boguñá, Marián; Bianconi, Ginestra; Krioukov, Dmitri

    2015-04-01

    All real networks are different, but many have some structural properties in common. There seems to be no consensus on what the most common properties are, but scale-free degree distributions, strong clustering, and community structure are frequently mentioned without question. Surprisingly, there exists no simple generative mechanism explaining all the three properties at once in growing networks. Here we show how latent network geometry coupled with preferential attachment of nodes to this geometry fills this gap. We call this mechanism geometric preferential attachment (GPA), and validate it against the Internet. GPA gives rise to soft communities that provide a different perspective on the community structure in networks. The connections between GPA and cosmological models, including inflation, are also discussed.

  9. Granger causality stock market networks: Temporal proximity and preferential attachment

    NASA Astrophysics Data System (ADS)

    Výrost, Tomáš; Lyócsa, Štefan; Baumöhl, Eduard

    2015-06-01

    The structure of return spillovers is examined by constructing Granger causality networks using daily closing prices of 20 developed markets from 2nd January 2006 to 31st December 2013. The data is properly aligned to take into account non-synchronous trading effects. The study of the resulting networks of over 94 sub-samples revealed three significant findings. First, after the recent financial crisis the impact of the US stock market has declined. Second, spatial probit models confirmed the role of the temporal proximity between market closing times for return spillovers, i.e. the time distance between national stock markets matters. Third, a preferential attachment between stock markets exists, i.e. the probability of the presence of spillover effects between any given two markets increases with their degree of connectedness to others.

  10. Complex networks as an emerging property of hierarchical preferential attachment

    NASA Astrophysics Data System (ADS)

    Hébert-Dufresne, Laurent; Laurence, Edward; Allard, Antoine; Young, Jean-Gabriel; Dubé, Louis J.

    2015-12-01

    Real complex systems are not rigidly structured; no clear rules or blueprints exist for their construction. Yet, amidst their apparent randomness, complex structural properties universally emerge. We propose that an important class of complex systems can be modeled as an organization of many embedded levels (potentially infinite in number), all of them following the same universal growth principle known as preferential attachment. We give examples of such hierarchy in real systems, for instance, in the pyramid of production entities of the film industry. More importantly, we show how real complex networks can be interpreted as a projection of our model, from which their scale independence, their clustering, their hierarchy, their fractality, and their navigability naturally emerge. Our results suggest that complex networks, viewed as growing systems, can be quite simple, and that the apparent complexity of their structure is largely a reflection of their unobserved hierarchical nature.

  11. Understanding the Role of Solvation Forces on the Preferential Attachment of Nanoparticles in Liquid.

    PubMed

    Welch, David A; Woehl, Taylor J; Park, Chiwoo; Faller, Roland; Evans, James E; Browning, Nigel D

    2016-01-26

    Optimization of colloidal nanoparticle synthesis techniques requires an understanding of underlying particle growth mechanisms. Nonclassical growth mechanisms are particularly important as they affect nanoparticle size and shape distributions, which in turn influence functional properties. For example, preferential attachment of nanoparticles is known to lead to the formation of mesocrystals, although the formation mechanism is currently not well-understood. Here we employ in situ liquid cell scanning transmission electron microscopy and steered molecular dynamics (SMD) simulations to demonstrate that the experimentally observed preference for end-to-end attachment of silver nanorods is a result of weaker solvation forces occurring at rod ends. SMD reveals that when the side of a nanorod approaches another rod, perturbation in the surface-bound water at the nanorod surface creates significant energy barriers to attachment. Additionally, rod morphology (i.e., facet shape) effects can explain the majority of the side attachment effects that are observed experimentally. PMID:26588243

  12. Understanding the Role of Solvation Forces on the Preferential Attachment of Nanoparticles in Liquid

    SciTech Connect

    Welch, David A.; Woehl, Taylor J.; Park, Chiwoo; Faller, Roland; Evans, James E.; Browning, Nigel D.

    2015-11-20

    We discuss optimization of colloidal nanoparticle synthesis techniques, which requires an understanding of underlying particle growth mechanisms. Nonclassical growth mechanisms are particularly important as they affect nanoparticle size and shape distributions, which in turn influence functional properties. For example, preferential attachment of nanoparticles is known to lead to the formation of mesocrystals, although the formation mechanism is currently not well-understood. Here we employ in situ liquid cell scanning transmission electron microscopy and steered molecular dynamics (SMD) simulations to demonstrate that the experimentally observed preference for end-to-end attachment of silver nanorods is a result of weaker solvation forces occurring at rod ends. In conclusion, SMD reveals that when the side of a nanorod approaches another rod, perturbation in the surface-bound water at the nanorod surface creates significant energy barriers to attachment. Additionally, rod morphology (i.e., facet shape) effects can explain the majority of the side attachment effects that are observed experimentally.

  13. Understanding the Role of Solvation Forces on the Preferential Attachment of Nanoparticles in Liquid

    DOE PAGESBeta

    Welch, David A.; Woehl, Taylor J.; Park, Chiwoo; Faller, Roland; Evans, James E.; Browning, Nigel D.

    2015-11-20

    We discuss optimization of colloidal nanoparticle synthesis techniques, which requires an understanding of underlying particle growth mechanisms. Nonclassical growth mechanisms are particularly important as they affect nanoparticle size and shape distributions, which in turn influence functional properties. For example, preferential attachment of nanoparticles is known to lead to the formation of mesocrystals, although the formation mechanism is currently not well-understood. Here we employ in situ liquid cell scanning transmission electron microscopy and steered molecular dynamics (SMD) simulations to demonstrate that the experimentally observed preference for end-to-end attachment of silver nanorods is a result of weaker solvation forces occurring at rodmore » ends. In conclusion, SMD reveals that when the side of a nanorod approaches another rod, perturbation in the surface-bound water at the nanorod surface creates significant energy barriers to attachment. Additionally, rod morphology (i.e., facet shape) effects can explain the majority of the side attachment effects that are observed experimentally.« less

  14. Joint estimation of preferential attachment and node fitness in growing complex networks

    PubMed Central

    Pham, Thong; Sheridan, Paul; Shimodaira, Hidetoshi

    2016-01-01

    Complex network growth across diverse fields of science is hypothesized to be driven in the main by a combination of preferential attachment and node fitness processes. For measuring the respective influences of these processes, previous approaches make strong and untested assumptions on the functional forms of either the preferential attachment function or fitness function or both. We introduce a Bayesian statistical method called PAFit to estimate preferential attachment and node fitness without imposing such functional constraints that works by maximizing a log-likelihood function with suitably added regularization terms. We use PAFit to investigate the interplay between preferential attachment and node fitness processes in a Facebook wall-post network. While we uncover evidence for both preferential attachment and node fitness, thus validating the hypothesis that these processes together drive complex network evolution, we also find that node fitness plays the bigger role in determining the degree of a node. This is the first validation of its kind on real-world network data. But surprisingly the rate of preferential attachment is found to deviate from the conventional log-linear form when node fitness is taken into account. The proposed method is implemented in the R package PAFit. PMID:27601314

  15. Joint estimation of preferential attachment and node fitness in growing complex networks.

    PubMed

    Pham, Thong; Sheridan, Paul; Shimodaira, Hidetoshi

    2016-01-01

    Complex network growth across diverse fields of science is hypothesized to be driven in the main by a combination of preferential attachment and node fitness processes. For measuring the respective influences of these processes, previous approaches make strong and untested assumptions on the functional forms of either the preferential attachment function or fitness function or both. We introduce a Bayesian statistical method called PAFit to estimate preferential attachment and node fitness without imposing such functional constraints that works by maximizing a log-likelihood function with suitably added regularization terms. We use PAFit to investigate the interplay between preferential attachment and node fitness processes in a Facebook wall-post network. While we uncover evidence for both preferential attachment and node fitness, thus validating the hypothesis that these processes together drive complex network evolution, we also find that node fitness plays the bigger role in determining the degree of a node. This is the first validation of its kind on real-world network data. But surprisingly the rate of preferential attachment is found to deviate from the conventional log-linear form when node fitness is taken into account. The proposed method is implemented in the R package PAFit. PMID:27601314

  16. Transcriptional Network Growing Models Using Motif-Based Preferential Attachment

    PubMed Central

    Abdelzaher, Ahmed F.; Al-Musawi, Ahmad F.; Ghosh, Preetam; Mayo, Michael L.; Perkins, Edward J.

    2015-01-01

    Understanding relationships between architectural properties of gene-regulatory networks (GRNs) has been one of the major goals in systems biology and bioinformatics, as it can provide insights into, e.g., disease dynamics and drug development. Such GRNs are characterized by their scale-free degree distributions and existence of network motifs – i.e., small-node subgraphs that occur more abundantly in GRNs than expected from chance alone. Because these transcriptional modules represent “building blocks” of complex networks and exhibit a wide range of functional and dynamical properties, they may contribute to the remarkable robustness and dynamical stability associated with the whole of GRNs. Here, we developed network-construction models to better understand this relationship, which produce randomized GRNs by using transcriptional motifs as the fundamental growth unit in contrast to other methods that construct similar networks on a node-by-node basis. Because this model produces networks with a prescribed lower bound on the number of choice transcriptional motifs (e.g., downlinks, feed-forward loops), its fidelity to the motif distributions observed in model organisms represents an improvement over existing methods, which we validated by contrasting their resultant motif and degree distributions against existing network-growth models and data from the model organism of the bacterium Escherichia coli. These models may therefore serve as novel testbeds for further elucidating relationships between the topology of transcriptional motifs and network-wide dynamical properties. PMID:26528473

  17. Network growth with preferential attachment and without “rich get richer” mechanism

    NASA Astrophysics Data System (ADS)

    Lachgar, A.; Achahbar, A.

    2016-08-01

    We propose a simple preferential attachment model of growing network using the complementary probability of Barabási-Albert (BA) model, i.e. Π(ki)∝1-ki∑jkj. In this network, new nodes are preferentially attached to not well connected nodes. Numerical simulations, in perfect agreement with the master equation solution, give an exponential degree distribution. This suggests that the power law degree distribution is a consequence of preferential attachment probability together with “rich get richer” phenomena. We also calculate the average degree of a target node at time t() and its fluctuations, to have a better view of the microscopic evolution of the network, and we also compare the results with BA model.

  18. Network growth with preferential attachment for high indegree and low outdegree

    NASA Astrophysics Data System (ADS)

    Sevim, Volkan; Rikvold, Per Arne

    2008-04-01

    We study the growth of a directed transportation network, such as a food web, in which links carry resources. We propose a growth process in which new nodes (or species) preferentially attach to existing nodes with high indegree (in food-web language, number of prey) and low outdegree (or number of predators). This scheme, which we call inverse preferential attachment, is intended to maximize the amount of resources available to each new node. We show that the outdegree (predator) distribution decays at least exponentially fast for large outdegree and is continuously tunable between an exponential distribution and a delta function. The indegree (prey) distribution is poissonian in the large-network limit.

  19. Statistical properties and attack tolerance of growing networks with algebraic preferential attachment

    NASA Astrophysics Data System (ADS)

    Liu, Zonghua; Lai, Ying-Cheng; Ye, Nong

    2002-09-01

    We consider growing networks with algebraic preferential attachment and address two questions: (1) what is the effect of temporal fluctuations in the number of new links acquired by the network? and (2) what is the network tolerance against random failures and intentional attacks? We find that the fluctuations generally have little effect on the network properties, although they lead to a plateau behavior for small degrees in the connectivity distribution. Formulas are derived for the evolution and distribution of the network connectivity, which are tested by numerical simulations. Numerical study of the effect of failures and attacks suggests that networks constructed under algebraic preferential attachment are more robust than scale-free networks.

  20. PAFit: A Statistical Method for Measuring Preferential Attachment in Temporal Complex Networks

    PubMed Central

    Pham, Thong; Sheridan, Paul; Shimodaira, Hidetoshi

    2015-01-01

    Preferential attachment is a stochastic process that has been proposed to explain certain topological features characteristic of complex networks from diverse domains. The systematic investigation of preferential attachment is an important area of research in network science, not only for the theoretical matter of verifying whether this hypothesized process is operative in real-world networks, but also for the practical insights that follow from knowledge of its functional form. Here we describe a maximum likelihood based estimation method for the measurement of preferential attachment in temporal complex networks. We call the method PAFit, and implement it in an R package of the same name. PAFit constitutes an advance over previous methods primarily because we based it on a nonparametric statistical framework that enables attachment kernel estimation free of any assumptions about its functional form. We show this results in PAFit outperforming the popular methods of Jeong and Newman in Monte Carlo simulations. What is more, we found that the application of PAFit to a publically available Flickr social network dataset yielded clear evidence for a deviation of the attachment kernel from the popularly assumed log-linear form. Independent of our main work, we provide a correction to a consequential error in Newman’s original method which had evidently gone unnoticed since its publication over a decade ago. PMID:26378457

  1. Assortativity and leadership emerge from anti-preferential attachment in heterogeneous networks

    NASA Astrophysics Data System (ADS)

    Sendiña-Nadal, I.; Danziger, M. M.; Wang, Z.; Havlin, S.; Boccaletti, S.

    2016-02-01

    Real-world networks have distinct topologies, with marked deviations from purely random networks. Many of them exhibit degree-assortativity, with nodes of similar degree more likely to link to one another. Though microscopic mechanisms have been suggested for the emergence of other topological features, assortativity has proven elusive. Assortativity can be artificially implanted in a network via degree-preserving link permutations, however this destroys the graph’s hierarchical clustering and does not correspond to any microscopic mechanism. Here, we propose the first generative model which creates heterogeneous networks with scale-free-like properties in degree and clustering distributions and tunable realistic assortativity. Two distinct populations of nodes are incrementally added to an initial network by selecting a subgraph to connect to at random. One population (the followers) follows preferential attachment, while the other population (the potential leaders) connects via anti-preferential attachment: they link to lower degree nodes when added to the network. By selecting the lower degree nodes, the potential leader nodes maintain high visibility during the growth process, eventually growing into hubs. The evolution of links in Facebook empirically validates the connection between the initial anti-preferential attachment and long term high degree. In this way, our work sheds new light on the structure and evolution of social networks.

  2. Assortativity and leadership emerge from anti-preferential attachment in heterogeneous networks.

    PubMed

    Sendiña-Nadal, I; Danziger, M M; Wang, Z; Havlin, S; Boccaletti, S

    2016-01-01

    Real-world networks have distinct topologies, with marked deviations from purely random networks. Many of them exhibit degree-assortativity, with nodes of similar degree more likely to link to one another. Though microscopic mechanisms have been suggested for the emergence of other topological features, assortativity has proven elusive. Assortativity can be artificially implanted in a network via degree-preserving link permutations, however this destroys the graph's hierarchical clustering and does not correspond to any microscopic mechanism. Here, we propose the first generative model which creates heterogeneous networks with scale-free-like properties in degree and clustering distributions and tunable realistic assortativity. Two distinct populations of nodes are incrementally added to an initial network by selecting a subgraph to connect to at random. One population (the followers) follows preferential attachment, while the other population (the potential leaders) connects via anti-preferential attachment: they link to lower degree nodes when added to the network. By selecting the lower degree nodes, the potential leader nodes maintain high visibility during the growth process, eventually growing into hubs. The evolution of links in Facebook empirically validates the connection between the initial anti-preferential attachment and long term high degree. In this way, our work sheds new light on the structure and evolution of social networks. PMID:26887684

  3. Assortativity and leadership emerge from anti-preferential attachment in heterogeneous networks

    PubMed Central

    Sendiña-Nadal, I.; Danziger, M. M.; Wang, Z.; Havlin, S.; Boccaletti, S.

    2016-01-01

    Real-world networks have distinct topologies, with marked deviations from purely random networks. Many of them exhibit degree-assortativity, with nodes of similar degree more likely to link to one another. Though microscopic mechanisms have been suggested for the emergence of other topological features, assortativity has proven elusive. Assortativity can be artificially implanted in a network via degree-preserving link permutations, however this destroys the graph’s hierarchical clustering and does not correspond to any microscopic mechanism. Here, we propose the first generative model which creates heterogeneous networks with scale-free-like properties in degree and clustering distributions and tunable realistic assortativity. Two distinct populations of nodes are incrementally added to an initial network by selecting a subgraph to connect to at random. One population (the followers) follows preferential attachment, while the other population (the potential leaders) connects via anti-preferential attachment: they link to lower degree nodes when added to the network. By selecting the lower degree nodes, the potential leader nodes maintain high visibility during the growth process, eventually growing into hubs. The evolution of links in Facebook empirically validates the connection between the initial anti-preferential attachment and long term high degree. In this way, our work sheds new light on the structure and evolution of social networks. PMID:26887684

  4. Preferential attachment in the growth of social networks: The internet encyclopedia Wikipedia

    NASA Astrophysics Data System (ADS)

    Capocci, A.; Servedio, V. D. P.; Colaiori, F.; Buriol, L. S.; Donato, D.; Leonardi, S.; Caldarelli, G.

    2006-09-01

    We present an analysis of the statistical properties and growth of the free on-line encyclopedia Wikipedia. By describing topics by vertices and hyperlinks between them as edges, we can represent this encyclopedia as a directed graph. The topological properties of this graph are in close analogy with those of the World Wide Web, despite the very different growth mechanism. In particular, we measure a scale-invariant distribution of the in and out degree and we are able to reproduce these features by means of a simple statistical model. As a major consequence, Wikipedia growth can be described by local rules such as the preferential attachment mechanism, though users, who are responsible of its evolution, can act globally on the network.

  5. Preferential attachment in the growth of social networks: the internet encyclopedia Wikipedia.

    PubMed

    Capocci, A; Servedio, V D P; Colaiori, F; Buriol, L S; Donato, D; Leonardi, S; Caldarelli, G

    2006-09-01

    We present an analysis of the statistical properties and growth of the free on-line encyclopedia Wikipedia. By describing topics by vertices and hyperlinks between them as edges, we can represent this encyclopedia as a directed graph. The topological properties of this graph are in close analogy with those of the World Wide Web, despite the very different growth mechanism. In particular, we measure a scale-invariant distribution of the in and out degree and we are able to reproduce these features by means of a simple statistical model. As a major consequence, Wikipedia growth can be described by local rules such as the preferential attachment mechanism, though users, who are responsible of its evolution, can act globally on the network. PMID:17025717

  6. Random Graphs Associated to Some Discrete and Continuous Time Preferential Attachment Models

    NASA Astrophysics Data System (ADS)

    Pachon, Angelica; Polito, Federico; Sacerdote, Laura

    2016-03-01

    We give a common description of Simon, Barabási-Albert, II-PA and Price growth models, by introducing suitable random graph processes with preferential attachment mechanisms. Through the II-PA model, we prove the conditions for which the asymptotic degree distribution of the Barabási-Albert model coincides with the asymptotic in-degree distribution of the Simon model. Furthermore, we show that when the number of vertices in the Simon model (with parameter α ) goes to infinity, a portion of them behave as a Yule model with parameters (λ ,β ) = (1-α ,1), and through this relation we explain why asymptotic properties of a random vertex in Simon model, coincide with the asymptotic properties of a random genus in Yule model. As a by-product of our analysis, we prove the explicit expression of the in-degree distribution for the II-PA model, given without proof in Newman (Contemp Phys 46:323-351, 2005). References to traditional and recent applications of the these models are also discussed.

  7. Dynamics of dissociative electron attachment to ammonia

    NASA Astrophysics Data System (ADS)

    Rescigno, T. N.; Trevisan, C. S.; Orel, A. E.; Slaughter, D. S.; Adaniya, H.; Belkacem, A.; Weyland, Marvin; Dorn, Alexander; McCurdy, C. W.

    2016-05-01

    Ab initio theoretical studies and momentum-imaging experiments are combined to provide a consistent picture of the dynamics of dissociative electron attachment to ammonia through its 5.5- and 10.5-eV resonance channels. The present study clarifies the character and symmetry of the anion states involved and the dynamics that leads to the observed fragment-ion channels, their branching ratios, and angular distributions.

  8. Imaging the molecular dynamics of dissociative electron attachment to water

    SciTech Connect

    Adaniya, Hidihito; Rudek, B.; Osipov, Timur; Haxton, Dan; Weber, Thorsten; Rescigno, Thomas N.; McCurdy, C.W.; Belkacem, Ali

    2009-10-19

    Momentum imaging experiments on dissociative electron attachment to the water molecule are combined with ab initio theoretical calculations of the angular dependence of the quantum mechanical amplitude for electron attachment to provide a detailed picture of the molecular dynamics of dissociation attachment via the two lowest energy Feshbach resonances. The combination of momentum imaging experiments and theory can reveal dissociation dynamics for which the axial recoil approximation breaks down and thus provides a powerful reaction microscope for DEA to polyatomics.

  9. Dynamic attachment of Chlorovirus PBCV-1 to Chlorella variabilis.

    PubMed

    Agarkova, Irina; Hertel, Brigitte; Zhang, Xinzheng; Lane, Les; Tchourbanov, Alexander; Dunigan, David D; Thiel, Gerhard; Rossmann, Michael G; Van Etten, James L

    2014-10-01

    Chloroviruses infect their hosts by specifically binding to and degrading the cell wall of their algal hosts at the site of attachment, using an intrinsic digesting enzyme(s). Chlorovirus PBCV-1 stored as a lysate survived longer than virus alone, suggesting virus attachment to cellular debris may be reversible. Ghost cells (algal cells extracted with methanol) were used as a model to study reversibility of PBCV-1 attachment because ghost cells are as susceptible to attachment and wall digestion as are live cells. Reversibility of attachment to ghost cells was examined by releasing attached virions with a cell wall degrading enzyme extract. The majority of the released virions retained infectivity even after re-incubating the released virions with ghost cells two times. Thus the chloroviruses appear to have a dynamic attachment strategy that may be beneficial in indigenous environments where cell wall debris can act as a refuge until appropriate host cells are available. PMID:25240455

  10. Dynamics of Dissociative Electron Attachment to Methane

    NASA Astrophysics Data System (ADS)

    Rescigno, T. N.; Douguet, N.; Fonseca, S.; Orel, A. E.; Slaughter, D. S.; Belkacem, A.

    2015-05-01

    We present the results of a theoretical ad experimental study of dissociative electron attachment (DEA) to CH4. The total DEA cross section is dominated by a single broad peak centered near 10 eV, leading predominantly to H-/CH4 and CH2-/CH4dissociation channels. We will present evidence that both of these ion channels result from excitation of a triply degenerate Feshbach resonance (doubly excited negative ion state) of 2T2 symmetry whose parent is the lowest excited triplet state of the neutral molecule. We will present calculated angular distributions based on analysis of the entrance amplitudes obtained from the results of complex Kohn scattering calculations along with experimentally measured angular distributions obtained using the COLTRIMS method. Work performed under the auspices of the US DOE by the LBNL and supported by the U.S. DOE Office of Basic Energy Sciences, Division of Chemical Sciences.

  11. Preferential cell attachment to nitrogen-doped diamond-like carbon (DLC:N) for the measurement of quantal exocytosis

    PubMed Central

    Sen, Atanu; Barizuddin, Syed; Hossain, Maruf; Polo-Parada, Luis; Gillis, Kevin D.; Gangopadhyay, Shubhra

    2013-01-01

    Electrochemical measurement of transmitter or hormone release from individual cells on microchips has applications both in basic science and drug screening. High-resolution measurement of quantal exocytosis requires the working electrode to be small (cell-sized) and located in immediate proximity to the cell. We examined the ability of candidate electrode materials to promote the attachment of two hormone-secreting cell types as a mechanism for targeting cells for to recording electrodes with high precision. We found that nitrogen-doped diamond-like carbon (DLC:N) promoted cell attachment relative to other materials tested in the rank order of DLC:N > In2O3/SnO2 (ITO), Pt > Au. In addition, we found that treating candidate electrode materials with polylysine did not increase attachment of chromaffin cells to DLC:N, but promoted cell attachment to the other tested materials. We found that hormone-secreting cells did not attach readily to Teflon AF as a potential insulating material, and demonstrated that patterning of Teflon AF leads to selective cell targeting to DLC:N “docking sites”. These results will guide the design of the next generation of biochips for automated and high-throughput measurement of quantal exocytosis. PMID:19124153

  12. Post-learning Hippocampal Dynamics Promote Preferential Retention of Rewarding Events.

    PubMed

    Gruber, Matthias J; Ritchey, Maureen; Wang, Shao-Fang; Doss, Manoj K; Ranganath, Charan

    2016-03-01

    Reward motivation is known to modulate memory encoding, and this effect depends on interactions between the substantia nigra/ventral tegmental area complex (SN/VTA) and the hippocampus. It is unknown, however, whether these interactions influence offline neural activity in the human brain that is thought to promote memory consolidation. Here we used fMRI to test the effect of reward motivation on post-learning neural dynamics and subsequent memory for objects that were learned in high- and low-reward motivation contexts. We found that post-learning increases in resting-state functional connectivity between the SN/VTA and hippocampus predicted preferential retention of objects that were learned in high-reward contexts. In addition, multivariate pattern classification revealed that hippocampal representations of high-reward contexts were preferentially reactivated during post-learning rest, and the number of hippocampal reactivations was predictive of preferential retention of items learned in high-reward contexts. These findings indicate that reward motivation alters offline post-learning dynamics between the SN/VTA and hippocampus, providing novel evidence for a potential mechanism by which reward could influence memory consolidation. PMID:26875624

  13. Stalking as paranoid attachment: a typological and dynamic model.

    PubMed

    Wilson, John S; Ermshar, Annette L; Welsh, Robert K

    2006-06-01

    Stalking encompasses a wide range of behavioral patterns, risk factors, interpersonal dynamics, and dangerousness. To account for these diverse phenomena, we propose that stalking behavior is best conceptualized by a dynamic interaction of attachment styles and psychodynamic phenomena. This paper articulates a model that explains stalking behavior within the framework of attachment theory. Four prototypical configurations of stalkers and their victims are developed. Each configuration is discussed in terms of a pattern of internal representations, affective constellations, combinations of aggression and narcissism, and potential for future violence. The four configurations proposed here are maintained through stalkers' over ideational linkage fantasies and projective identifications, which range from shame-prone and needy idealization to malevolent torment of the victim. Our model arrays erotomanic, jealous, and persecutory attachments along a continuum of increasingly paranoid and pathological identifications. We argue that these prototypical attachment configurations provide a theoretically driven means of differentiating phases of stalking, and as such provide useful leads in the empirical study and clinical assessment, treatment, and management of stalkers. PMID:16818420

  14. Preferential sites for InAsP/InP quantum wire nucleation using molecular dynamics

    NASA Astrophysics Data System (ADS)

    Nuñez-Moraleda, Bernardo; Pizarro, Joaquin; Guerrero, Elisa; Guerrero-Lebrero, Maria P.; Yáñez, Andres; Molina, Sergio Ignacio; Galindo, Pedro Luis

    2014-11-01

    In this paper, stress fields at the surface of the capping layer of self-assembled InAsP quantum wires grown on an InP (001) substrate have been determined from atomistic models using molecular dynamics and Stillinger-Weber potentials. To carry out these calculations, the quantum wire compositional distribution was extracted from previous works, where the As and P distributions were determined by electron energy loss spectroscopy and high-resolution aberration-corrected Z-contrast imaging. Preferential sites for the nucleation of wires on the surface of the capping layer were studied and compared with (i) previous simulations using finite element analysis to solve anisotropic elastic theory equations and (ii) experimentally measured locations of stacked wires. Preferential nucleation sites of stacked wires were determined by the maximum stress location at the MD model surface in good agreement with experimental results and those derived from finite element analysis. This indicates that MD simulations based on empirical potentials provide a suitable and flexible tool to study strain dependent atom processes.

  15. Biofilm attachment reduction on bioinspired, dynamic, micro-wrinkling surfaces

    NASA Astrophysics Data System (ADS)

    Epstein, Alexander K.; Hong, Donggyoon; Kim, Philseok; Aizenberg, Joanna

    2013-09-01

    Most bacteria live in multicellular communities known as biofilms that are adherent to surfaces in our environment, from sea beds to plumbing systems. Biofilms are often associated with clinical infections, nosocomial deaths and industrial damage such as bio-corrosion and clogging of pipes. As mature biofilms are extremely challenging to eradicate once formed, prevention is advantageous over treatment. However, conventional surface chemistry strategies are either generally transient, due to chemical masking, or toxic, as in the case of leaching marine antifouling paints. Inspired by the nonfouling skins of echinoderms and other marine organisms, which possess highly dynamic surface structures that mechanically frustrate bio-attachment, we have developed and tested a synthetic platform based on both uniaxial mechanical strain and buckling-induced elastomer microtopography. Bacterial biofilm attachment to the dynamic substrates was studied under an array of parameters, including strain amplitude and timescale (1-100 mm s-1), surface wrinkle length scale, bacterial species and cell geometry, and growth time. The optimal conditions for achieving up to ˜ 80% Pseudomonas aeruginosa biofilm reduction after 24 h growth and ˜ 60% reduction after 48 h were combinatorially elucidated to occur at 20% strain amplitude, a timescale of less than ˜ 5 min between strain cycles and a topography length scale corresponding to the cell dimension of ˜ 1 μm. Divergent effects on the attachment of P. aeruginosa, Staphylococcus aureus and Escherichia coli biofilms showed that the dynamic substrate also provides a new means of species-specific biofilm inhibition, or inversely, selection for a desired type of bacteria, without reliance on any toxic or transient surface chemical treatments.

  16. Preliminary evaluation of the effect of a dynamic preferential runway system upon community noise disturbance

    NASA Technical Reports Server (NTRS)

    Patterson, H. P.; Edmiston, R. P.; Connor, W. K.

    1972-01-01

    A dynamic preferential runway system (DPRS) was developed for John F. Kennedy International Airport for the purpose of controlling short term noise exposure in the neighboring communities. The DPRS is a computer-aided procedure for optimum selection of runways from the standpoint of noise and is based upon a community disturbance model which takes into account flyover levels, size of exposed populations, time of day and week, and persistence of overflights. A preliminary evaluation of the DPRS is presented on the basis of social survey data and telephone complaint records, for the trial period of August and September, 1971. Comparative use is made of data taken in a previous survey of the same community areas in 1969.

  17. Dismissing Attachment Characteristics Dynamically Modulate Brain Networks Subserving Social Aversion

    PubMed Central

    Krause, Anna Linda; Borchardt, Viola; Li, Meng; van Tol, Marie-José; Demenescu, Liliana Ramona; Strauss, Bernhard; Kirchmann, Helmut; Buchheim, Anna; Metzger, Coraline D.; Nolte, Tobias; Walter, Martin

    2016-01-01

    Attachment patterns influence actions, thoughts and feeling through a person’s “inner working model”. Speech charged with attachment-dependent content was proposed to modulate the activation of cognitive-emotional schemata in listeners. We performed a 7 Tesla rest-task-rest functional magnetic resonance imaging (fMRI)-experiment, presenting auditory narratives prototypical of dismissing attachment representations to investigate their effect on 23 healthy males. We then examined effects of participants’ attachment style and childhood trauma on brain state changes using seed-based functional connectivity (FC) analyses, and finally tested whether subjective differences in responsivity to narratives could be predicted by baseline network states. In comparison to a baseline state, we observed increased FC in a previously described “social aversion network” including dorsal anterior cingulated cortex (dACC) and left anterior middle temporal gyrus (aMTG) specifically after exposure to insecure-dismissing attachment narratives. Increased dACC-seeded FC within the social aversion network was positively related to the participants’ avoidant attachment style and presence of a history of childhood trauma. Anxious attachment style on the other hand was positively correlated with FC between the dACC and a region outside of the “social aversion network”, namely the dorsolateral prefrontal cortex, which suggests decreased network segregation as a function of anxious attachment. Finally, the extent of subjective experience of friendliness towards the dismissing narrative was predicted by low baseline FC-values between hippocampus and inferior parietal lobule (IPL). Taken together, our study demonstrates an activation of networks related to social aversion in terms of increased connectivity after listening to insecure-dismissing attachment narratives. A causal interrelation of brain state changes and subsequent changes in social reactivity was further supported by

  18. Dynamic of bacterial communities attached to lightened phytodetritus.

    PubMed

    Petit, Morgan; Bonin, Patricia; Amiraux, Rémi; Michotey, Valérie; Guasco, Sophie; Armitano, Joshua; Jourlin-Castelli, Cécile; Vaultier, Frédéric; Méjean, Vincent; Rontani, Jean-François

    2015-09-01

    The effects of singlet oxygen ((1)O2) transfer to bacteria attached on phytodetritus were investigated under laboratory-controlled conditions. For this purpose, a nonaxenic culture of Emiliania huxleyi in late stationary phase was studied for bacterial viability. Our results indicated that only 9 ± 3% of attached bacteria were alive compared to 46 ± 23% for free bacteria in the E. huxleyi culture. Apparently, under conditions of low irradiance (36 W m(-2)), during the culture, the cumulative dose received (22,000 kJ m(-2)) was sufficiently important to induce an efficient (1)O2 transfer to attached bacteria during the senescence of E. huxleyi cells. At this stage, attached bacteria appeared to be dominated by pigmented bacteria (Maribacter, Roseobacter, Roseovarius), which should resist to (1)O2 stress probably due to their high contents of carotenoids. After subsequent irradiation of the culture until fully photodegradation of chlorophyll, DGGE analyses showed that the diversity of bacteria attached to E. huxleyi cells is modified by light. Photooxidative alterations of bacteria were confirmed by the increasing amounts of cis-vaccenic photoproducts (bacterial marker) per bacteria observed during irradiation time. Interestingly, preliminary chemotaxis experiments showed that Shewanella oneidensis considered here as a model of motile bacteria was attracted by phytodetritus producing or not (1)O2. This lack of repulsive effects could explain the high mortality rate of bacteria measured on E. huxleyi cells. PMID:25687611

  19. Love as a Battlefield: Attachment and Relationship Dynamics in Couples Identified for Male Partner Violence

    ERIC Educational Resources Information Center

    Allison, Colleen J.; Bartholomew, Kim; Mayseless, Ofra; Dutton, Donald G.

    2008-01-01

    The authors explored the attachment dynamics of heterosexual couples identified for male partner violence. Based on semistructured interviews, participants were assessed for attachment orientations. Based on a thematic analysis of the interviews, two strategies for regulating distance within these relationships were identified: pursuit and…

  20. Nonlinear Dynamical Behavior in BS Evolution Model Based on Small-World Network Added with Mechanism of Preferential Connection

    NASA Astrophysics Data System (ADS)

    Zhang, Ying-Yue; Chen, Tian-Lun

    2006-03-01

    In this paper, we introduce a modified small-world network added with new links with preferential connection instead of adding randomly, then we apply Bak-Sneppen (BS) evolution model on this network. Several dynamical character of the model such as the evolution graph, f0 avalanche, the critical exponent D and τ, and the distribution of mutation times of all the nodes, show particular behaviors different from those of the model based on the regular network and the small-world network.

  1. Choose your own adventure: attachment dynamics in a simulated relationship.

    PubMed

    Vicary, Amanda M; Fraley, R Chris

    2007-09-01

    According to attachment theory, insecure individuals respond to events in their romantic relationships in ways that sometimes can be destructive. The objective of this research was to examine how these responses may accumulate over repeated interactions to influence the quality of the relationship. Across three studies, participants were presented with a "Choose Your Own Adventure" dating story in which they made choices based on their partners' behaviors. In each study we found that attachment styles predicted the kinds of choices participants made at the outset of and throughout the story. Additionally, relationship satisfaction was related to the choices participants made throughout the fictional narrative, even in situations in which the partner's behavior was the same for all participants. PMID:17933741

  2. The association between spouses' self-reports of attachment styles and representations of family dynamics.

    PubMed

    Mikulincer, M; Florian, V

    1999-01-01

    The current research assesses the association between spouses' self-reports of attachment style and their perceptions of family dynamics. The sample included 93 Israeli married couples with young children. Both husbands and wives completed the adult attachment style scale and the perceived and ideal versions of FACES III. Findings showed that spouses whose self-reports endorsed the secure style perceived relatively high levels of family cohesion and adaptability; persons who endorsed the anxious-ambivalent style reported high levels of family cohesion but low levels of adaptability; and persons who endorsed the avoidant style reported relatively low levels of both family dimensions. In addition, significant associations were found between reports of attachment styles, on the one hand, and ideal representations of family dynamics, the marital partner's representations of family dynamics, and spouses' discrepancies in these representations, on the other. Findings are discussed in terms of attachment theory. PMID:10207711

  3. On the use of attachment modes in substructure coupling for dynamic analysis

    NASA Technical Reports Server (NTRS)

    Craig, R. R., Jr.; Chang, C.-J.

    1977-01-01

    Substructure coupling or component-mode synthesis may be employed in the solution of dynamics problems for complex structures. Although numerous substructure-coupling methods have been devised, little attention has been devoted to methods employing attachment modes. In the present paper the various mode sets (normal modes, constraint modes, attachment modes) are defined. A generalized substructure-coupling procedure is described. Those substructure-coupling methods which employ attachment modes are described in detail. One of these methods is shown to lead to results (e.g., system natural frequencies) comparable to or better than those obtained by the Hurty (1965) method.

  4. Dynamic protein conformations preferentially drive energy transfer along the active chain of the photosystem II reaction centre.

    PubMed

    Zhang, Lu; Silva, Daniel-Adriano; Zhang, Houdao; Yue, Alexander; Yan, YiJing; Huang, Xuhui

    2014-01-01

    One longstanding puzzle concerning photosystem II, a core component of photosynthesis, is that only one of the two symmetric branches in its reaction centre is active in electron transfer. To investigate the effect of the photosystem II environment on the preferential selection of the energy transfer pathway (a prerequisite for electron transfer), we have constructed an exciton model via extensive molecular dynamics simulations and quantum mechanics/molecular mechanics calculations based on a recent X-ray structure. Our results suggest that it is essential to take into account an ensemble of protein conformations to accurately compute the site energies. We identify the cofactor CLA606 of active chain as the most probable site for the energy excitation. We further pinpoint a number of charged protein residues that collectively lower the CLA606 site energy. Our work provides insights into the understanding of molecular mechanisms of the core machinery of the green-plant photosynthesis. PMID:24954746

  5. Revealing Dissociative Electron Attachment Dynamics in Polyatomic Molecules Using Momentum Imaging Experiments and Electron Scattering Calculations

    NASA Astrophysics Data System (ADS)

    Belkacem, Ali; Slaughter, Daniel

    2015-05-01

    Understanding electron-driven chemical reactions is important for improving a variety of technological applications such as materials processing and the important role they play in the radiation damage in bulk matter. Furthermore, dissociative electron attachment often exhibits site-selective bond cleavage, which holds promise for prediction and precise control of electron-driven chemical reactions. Recent dynamical studies of these reactions have demonstrated that an understanding of anion dissociation dynamics beyond simple one-dimensional models is crucial in interpreting the measured fragment angular distributions. We combine ion fragment momentum imaging experiments with electron attachment entrance amplitude calculations to interrogate the non-Born-Oppenheimer dynamics of dissociative electron attachment in polyatomic molecules. We will report recent experimental developments in molecules of technological interest including methanol, methane and uracil. Work supported by Chemical Sciences, Geosciences and Biosciences division of BES/DOE.

  6. Ska1 cooperates with DDA3 for spindle dynamics and spindle attachment to kinetochore.

    PubMed

    Park, Ji Eun; Song, Haiyu; Kwon, Hye Jin; Jang, Chang-Young

    2016-02-12

    Spindle microtubules (MTs) capture kinetochores (KTs) on the centromere sequence of sister chromatids to align at the mitotic equator and segregate toward spindle poles during mitosis. For efficient chromosome capture, KTs initially attach to the lateral surface of a MT, providing a considerably larger contact surface than the MT tip. A sequential change of KT composition upon spindle attachment enables a conversion from lateral to stable end-on attachment. However, the molecular link between spindle dynamics and KT composition is not fully understood. Here, we report that Ska1 and DDA3 act as molecular linkers in the interplay between KTs and spindle dynamics. After recruitment of Kif2a onto the mitotic spindle by DDA3, Ska1 targets Kif2a to the minus-end of spindle MTs and facilitates spindle dynamics. Furthermore, DDA3 targets Ska1 to KTs to stabilize end-on attachment. Thus, our findings identified a definite regulatory mechanism of the search and capture process for stable spindle attachment through cross-talk between spindle dynamics and KT composition mediated by DDA3 and Ska1. PMID:26797278

  7. Modest Interference with Actin Dynamics in Primary T Cell Activation by Antigen Presenting Cells Preferentially Affects Lamellal Signaling

    PubMed Central

    Roybal, Kole T.; Mace, Emily M.; Clark, Danielle J.; Leard, Alan D.; Herman, Andrew; Verkade, Paul; Orange, Jordan S.; Wülfing, Christoph

    2015-01-01

    Dynamic subcellular distributions of signaling system components are critical regulators of cellular signal transduction through their control of molecular interactions. Understanding how signaling activity depends on such distributions and the cellular structures driving them is required for comprehensive insight into signal transduction. In the activation of primary murine T cells by antigen presenting cells (APC) signaling intermediates associate with various subcellular structures, prominently a transient, wide, and actin-associated lamellum extending from an interdigitated T cell:APC interface several micrometers into the T cell. While actin dynamics are well established as general regulators of cellular organization, their role in controlling signaling organization in primary T cell:APC couples and the specific cellular structures driving it is unresolved. Using modest interference with actin dynamics with a low concentration of Jasplakinolide as corroborated by costimulation blockade we show that T cell actin preferentially controls lamellal signaling localization and activity leading downstream to calcium signaling. Lamellal localization repeatedly related to efficient T cell function. This suggests that the transient lamellal actin matrix regulates T cell signaling associations that facilitate T cell activation. PMID:26237588

  8. Solvent-Driven Preferential Association of Lignin with Regions of Crystalline Cellulose in Molecular Dynamics Simulation

    SciTech Connect

    Lindner, Benjamin; Petridis, Loukas; Schulz, Roland; Smith, Jeremy C

    2013-01-01

    The precipitation of lignin onto cellulose after pretreatment of lignocellulosic biomass is an obstacle to economically viable cellulosic ethanol production. Here, 750 ns nonequilibrium molecular dynamics simulations are reported of a system of lignin and cellulose in aqueous solution. Lignin is found to strongly associate with itself and the cellulose. However, noncrystalline regions of cellulose are observed to have a lower tendency to associate with lignin than crystalline regions, and this is found to arise from stronger hydration of the noncrystalline chains. The results suggest that the recalcitrance of crystalline cellulose to hydrolysis arises not only from the inaccessibility of inner fibers but also due to the promotion of lignin adhesion.

  9. Propellant grain dynamics in aft attach ring of shuttle solid rocket booster

    NASA Technical Reports Server (NTRS)

    Verderaime, V.

    1979-01-01

    An analytical technique for implementing simultaneously the temperature, dynamic strain, real modulus, and frequency properties of solid propellant in an unsymmetrical vibrating ring mode is presented. All dynamic parameters and sources are defined for a free vibrating ring-grain structure with initial displacement and related to a forced vibrating system to determine the change in real modulus. Propellant test data application is discussed. The technique was developed to determine the aft attach ring stiffness of the shuttle booster at lift-off.

  10. Accelerating networks: Effects of preferential connections

    NASA Astrophysics Data System (ADS)

    Jeon, Y.-P.; McCoy, B. J.

    2007-12-01

    Networks are commonly observed structures in complex systems with interacting and interdependent parts that self-organize. For nonlinearly growing networks, when the total number of connections increases faster than the total number of nodes, the network is said to accelerate. We propose a systematic model for the dynamics of growing networks represented by distribution kinetics equations. We define the nodal-linkage distribution, construct a population dynamics equation based on the association-dissociation process, and perform the moment calculations to describe the dynamics of such networks. For nondirectional networks with finite numbers of nodes and connections, the moments are the total number of nodes, the total number of connections, and the degree (the average number of connections per node), represented by the average moment. Size independent rate coefficients yield an exponential network describing the network without preferential attachment, and size dependent rate coefficients produce a power law network with preferential attachment. The model quantitatively describes accelerating network growth data for a supercomputer (Earth Simulator), for regulatory gene networks, and for the Internet.

  11. Simultaneous dynamic optical and electrical properties of endothelial cell attachment on indium tin oxide bioelectrodes.

    PubMed

    Choi, Chang K; English, Anthony E; Kihm, Kenneth D; Margraves, Charles H

    2007-01-01

    This study quantifies the dynamic attachment and spreading of porcine pulmonary artery endothelial cells (PPAECs) on optically thin, indium tin oxide (ITO) biosensors using simultaneous differential interference contrast microscopy (DICM) and electrical microimpedance spectroscopy. A lock-in amplifier circuit monitored the impedance of PPAECs cultivated on the transparent ITO bioelectrodes as a function of frequency between 10 Hz and 100 kHz and as a function of time, while DICM images were simultaneously acquired. A digital image processing algorithm quantified the cell-covered electrode area as a function of time. The results of this study show that the fraction of the cell-covered electrode area is in qualitative agreement with the electrical impedance during the attachment phase following the cell settling on the electrode surface. The possibility of several distinctly different states of electrode coverage and cellular attachment giving rise to similar impedance signals is discussed. PMID:18163844

  12. Mother-Infant Verbal and Nonverbal Interaction as Predictor of Attachment: Nonlinear Dynamic Analyses.

    PubMed

    Cerezo, M Angeles; Pons-Salvador, Gemma; Trenado, Rosa M; Sierra, Purificacion

    2016-10-01

    This longitudinal study examined flexibility in early mother-infant interaction at the age of approximately 6 months (N=30) and whether flexibility indices predicted (in) secure child attachment at 15 months. Dyadic flexibility was measured using dynamic systems-based modelling of patterns during mother-child free play in terms of NDS variables derived from SSG: the propensity to change states (dynamic flexibility), number of states visited (diversity) and predictability (dispersion). Results showed significant discriminant functions on the attachment type groups, A, B & C, for the total grid, which included verbal and non-verbal, and for the reciprocal verbal region. Specifically, the prediction outcomes seem to work better in total grid for A-dyads and in the reciprocal verbal region for B and C-dyads. Diversity emerged as the most relevant index in dyadic flexibility: A-dyads showed the least diversity, distinguished them from B-dyads in the verbal regions, (both the reciprocal and non-reciprocal, 'child verbal-mother non-verbal' one), and, from C-dyads in the reciprocal non-verbal region. A-dyads showed remarkably low activity in the regions involving child verbal behavior, showing that children who became avoidant attached at 15 months of age, were mostly silent at approximately 6 months, when they interacted with their mothers. Findings in this study contribute to advancing conceptually informed measurement of dyadic interaction to provide a new perspective on maternal sensitivity and early markers of child insecure/secure attachment. PMID:27550705

  13. Observation of the dynamics leading to a conical intersection in dissociative electron attachment to water

    SciTech Connect

    Haxton, D.; Adaniya, H.; Slaughter, D. S.; Rudek, B.; Osipov, T.; Weber, T.; Rescigno, T. N.; McCurdy, C. W.; Belkacem, A.

    2011-08-11

    Following prior work on the lower-energy resonances, we apply techniques of momentum imaging and ab initio scattering calculations to the process of dissociative electron attachment to water via the highest-energy {sup 2}B{sub 2} resonance. We focus on the H{sup -} anion fragment, which is produced via dynamics passing through and avoiding the conical intersection with the lower A{sub 1} state, leading to OH ({sup 2}{Pi} ) and OH ({sup 2}{Sigma} ), respectively. The momentum imaging technique, when combined with theoretical calculations on the attachment amplitude and dissociation dynamics, demonstrates that the angular distributions provide a signature of the location of the conical intersection in the space of nuclear configurations.

  14. Observation of the dynamics leading to a conical intersection in dissociative electron attachment to water

    SciTech Connect

    Haxton, Dan; Adaniya, Hidihito; Slaughter, Dan; Rudek, B.; Osipov, Timur; Weber, Thorsten; Rescigno, Tom; McCurdy, Bill; Belkacem, Ali

    2011-06-08

    Following prior work on the lower-energy resonances, we apply techniques of momentum imaging and ab initio scattering calculations to the process of dissociative electron attachment to water via the highest-energy {sup 2}B{sub 2} resonance. We focus on the H{sup -} anion fragment, which is produced via dynamics passing through and avoiding the conical intersection with the lower A{sub 1} state, leading to OH ((sup 2}{Pi}#5;) and OH ({sup 2}{Sigma}#6;), respectively. The momentum imaging technique, when combined with theoretical calculations on the attachment amplitude and dissociation dynamics, demonstrates that the angular distributions provide a signature of the location of the conical intersection in the space of nuclear con#12;gurations.

  15. Signatures of bond formation and bond scission dynamics in dissociative electron attachment to methane.

    PubMed

    Douguet, N; Slaughter, D S; Adaniya, H; Belkacem, A; Orel, A E; Rescigno, T N

    2015-10-14

    We present a combined experimental and theoretical investigation of the dynamics and angular dependence of dissociative electron attachment to methane. We show that a triply degenerate (T2) Feshbach resonance is responsible for the broad 10 eV dissociation peak in methane. This resonance alone is shown to correlate asymptotically to the various dissociation channels observed experimentally. The molecular-frame entrance amplitude for electron attachment is calculated for each component of the threefold degenerate resonance. By investigating the topology of the anion potential energy surfaces, we deduce the main pathways to two- and three-body breakup channels involving both bond scission and bond formation. The computed fragment angular distributions reproduce the main trends of the experimental measurements. PMID:26371546

  16. End-to-surface reaction dynamics of a single surface-attached DNA or polypeptide.

    PubMed

    Cheng, Ryan R; Makarov, Dmitrii E

    2010-03-11

    The dynamics of surface-attached polymers play a key role in the operation of a number of biological sensors, yet its current understanding is rather limited. Here we use computer simulations to study the dynamics of a reaction between the free end of a polymer chain and a surface, to which its other end has been attached. We consider two limiting cases, the diffusion-controlled limit, where the reaction is accomplished whenever the free chain end diffuses to within a specified distance from the surface, and the reaction-controlled limit, where slow, intrinsic reaction kinetics rather than diffusion of the chain is rate limiting. In the diffusion-controlled limit, we find that the overall rate scales as N(-b), where N is the number of monomers in the chain and b approximately = 2.2 for excluded volume chains. This value of the scaling exponent b is close to that derived from a simple approximate theory treating the dynamics of the chain end relative to the surface as one-dimensional diffusion in an effective potential. In the reaction-controlled limit, the value of the scaling exponent b is close to 1. We compare our findings with those for the related (and better studied) problem of end-to-end reactions within an unconstrained polymer chain and discuss their implications for electrochemical DNA sensors. PMID:20151703

  17. Ab initio molecular dynamics simulation study of dissociative electron attachment to dialanine conformers.

    PubMed

    Feng, Wen-Ling; Tian, Shan Xi

    2015-03-12

    Dissociative electron attachment (DEA) processes of six low-lying conformers (1-6) of dialanine in the gas phase are investigated by using ab initio molecular dynamics simulations. The incoming electron is captured and primarily occupies the virtual molecular orbital π*, which is followed by the different dissociation processes. The electron attachments to conformers 1 and 2 having the stronger N-H···N and O-H···O intramolecular hydrogen bonds do not lead to fragmentations, but two different backbone bonds are broken in the DEAs to conformers 3 (or 4) and 6, respectively. It is interesting that the hydrogen abstraction of -NH from the terminal methyl group -CH3 is found in the roaming dissociation of the temporary anion of conformer 3. The present simulations enable us to have more insights into the peptide backbone bond breaks in the DEA process and demonstrate a promising way toward understanding of the radiation damages of complicated biological system. PMID:25679256

  18. Dynamics of solvation and desolvation of rubidium attached to He nanodroplets

    SciTech Connect

    Vangerow, J. von; John, O.; Stienkemeier, F.; Mudrich, M.

    2015-07-21

    The real-time dynamics of photoexcited and photoionized rubidium (Rb) atoms attached to helium (He) nanodroplets is studied by femtosecond pump-probe mass spectrometry. While excited Rb atoms in the perturbed 6p-state (Rb{sup *}) desorb off the He droplets, Rb{sup +} photoions tend to sink into the droplet interior when created near the droplet surface. The transition from Rb{sup +} solvation to full Rb{sup *} desorption is found to occur at a delay time τ ∼ 600 fs for Rb{sup *} in the 6pΣ-state and τ ∼ 1200 fs for the 6pΠ-state. Rb{sup +}He ions are found to be created by directly exciting bound Rb{sup *}He exciplex states as well as by populating bound Rb{sup +}He-states in a photoassociative ionization process.

  19. Dynamics of solvation and desolvation of rubidium attached to He nanodroplets.

    PubMed

    von Vangerow, J; John, O; Stienkemeier, F; Mudrich, M

    2015-07-21

    The real-time dynamics of photoexcited and photoionized rubidium (Rb) atoms attached to helium (He) nanodroplets is studied by femtosecond pump-probe mass spectrometry. While excited Rb atoms in the perturbed 6p-state (Rb*) desorb off the He droplets, Rb(+) photoions tend to sink into the droplet interior when created near the droplet surface. The transition from Rb(+) solvation to full Rb* desorption is found to occur at a delay time τ ∼ 600 fs for Rb* in the 6pΣ-state and τ ∼ 1200 fs for the 6pΠ-state. Rb(+)He ions are found to be created by directly exciting bound Rb*He exciplex states as well as by populating bound Rb(+)He-states in a photoassociative ionization process. PMID:26203022

  20. Flight Dynamics of an Aeroshell Using an Attached Inflatable Aerodynamic Decelerator

    NASA Technical Reports Server (NTRS)

    Cruz, Juan R.; Schoenenberger, Mark; Axdahl, Erik; Wilhite, Alan

    2009-01-01

    An aeroelastic analysis of the behavior of an entry vehicle utilizing an attached inflatable aerodynamic decelerator during supersonic flight is presented. The analysis consists of a planar, four degree of freedom simulation. The aeroshell and the IAD are assumed to be separate, rigid bodies connected with a spring-damper at an interface point constraining the relative motion of the two bodies. Aerodynamic forces and moments are modeled using modified Newtonian aerodynamics. The analysis includes the contribution of static aerodynamic forces and moments as well as pitch damping. Two cases are considered in the analysis: constant velocity flight and planar free flight. For the constant velocity and free flight cases with neutral pitch damping, configurations with highly-stiff interfaces exhibit statically stable but dynamically unstable aeroshell angle of attack. Moderately stiff interfaces exhibit static and dynamic stability of aeroshell angle of attack due to damping induced by the pitch angle rate lag between the aeroshell and IAD. For the free-flight case, low values of both the interface stiffness and damping cause divergence of the aeroshell angle of attack due to the offset of the IAD drag force with respect to the aeroshell center of mass. The presence of dynamic aerodynamic moments was found to influence the stability characteristics of the vehicle. The effect of gravity on the aeroshell angle of attack stability characteristics was determined to be negligible for the cases investigated.

  1. Preferential remineralization of dissolved organic phosphorus and non-Redfield DOM dynamics in the global ocean: Impacts on marine productivity, nitrogen fixation, and carbon export

    NASA Astrophysics Data System (ADS)

    Letscher, Robert T.; Moore, J. Keith

    2015-03-01

    Selective removal of nitrogen (N) and phosphorus (P) from the marine dissolved organic matter (DOM) pool has been reported in several regional studies. Because DOM is an important advective/mixing pathway of carbon (C) export from the ocean surface layer and its non-Redfieldian stoichiometry would affect estimates of marine export production per unit N and P, we investigated the stoichiometry of marine DOM and its remineralization globally using a compiled DOM data set. Marine DOM is enriched in C and N compared to Redfield stoichiometry, averaging 317:39:1 and 810:48:1 for C:N:P within the degradable and total bulk pools, respectively. Dissolved organic phosphorus (DOP) is found to be preferentially remineralized about twice as rapidly with respect to the enriched C:N stoichiometry of marine DOM. Biogeochemical simulations with the Biogeochemical Elemental Cycling model using Redfield and variable DOM stoichiometry corroborate the need for non-Redfield dynamics to match the observed DOM stoichiometry. From our model simulations, preferential DOP remineralization is found to increase the strength of the biological pump by ~9% versus the case of Redfield DOM cycling. Global net primary productivity increases ~10% including an increase in marine nitrogen fixation of ~26% when preferential DOP remineralization and direct utilization of DOP by phytoplankton are included. The largest increases in marine nitrogen fixation, net primary productivity, and carbon export are observed within the western subtropical gyres, suggesting the lateral transfer of P in the form of DOP from the productive eastern and poleward gyre margins may be important for sustaining these processes downstream in the subtropical gyres.

  2. Evaluation of the effects of one year's operation of the dynamic preferential runway system. [human reactions to overflight air traffic pattern

    NASA Technical Reports Server (NTRS)

    Borsky, P. N.

    1974-01-01

    The FAA introduced an experimental aircraft operations program at JFK Airport called the Dynamic Preferential Runway System (DPRS) in the summer of 1971. The program is designed to distribute air traffic as equally as possible over the surrounding communities, to limit periods of continuous overflight and to vary the same hours of overflight from day to day. After a full year's operation, an evaluation was made of the system's effectiveness. All of the operation's goals were moderately achieved with the greatest relief in reduced overflight afforded the most heavily impacted areas. Few residents, however, were aware of DPRS or felt that it had greatly reduced annoyance or represented a major effort by the aircraft authorities. Statistical analyses of reported annoyance obtained from two independent surveys in 1969 and 1972 reveal limited reductions in annoyance in 1972, with shifts from reported high annoyance to moderate annoyance.

  3. Chatter resistance of non-uniform turning bars with attached dynamic absorbers—Analytical approach

    NASA Astrophysics Data System (ADS)

    Saffury, J.; Altus, E.

    2010-05-01

    Forced harmonic vibration of a non-uniform elastic beam with attached dynamic vibration absorbers (DVA) is studied. Analytical approximation of the solution is obtained by the functional perturbation method (FPM). The problem has application to cutting tools operations where the resistance of the tool holder against regenerative chatter can be enhanced by optimizing the real part of the frequency response function (FRF). A test case of a beam with step-like heterogeneity and single DVA at the tip shows that the FPM solution is very accurate for up to ˜40 percent deviation in both stiffness and mass density. Using the analytical results and Sims approach, optimal DVA tuning is found for each set of beam heterogeneity parameters by solving a set of nonlinear algebraic equations numerically. It is found that the optimum can be further improved by searching for the best step location. The system optimization is then expanded to a general heterogeneous beam with a DVA at its tip. The mass and stiffness distribution is optimized by applying the Lagrange variation method on the FPM solution yielding Fredholm integral equations. The optimized morphology is found to be approximately linear and far from the "intuitive" step-like one (Rivin and Kang, 1992) and yields better chatter-resistance.

  4. Enriching practice of dialectic behaviour therapy with the dynamic maturational model of attachment and adaptation.

    PubMed

    Wilkinson, Simon R

    2016-01-01

    The major challenge for a clinician is integration of the wisdom available in the wide range of therapeutic paradigms available. I have found the principles guiding dialectic behaviour therapy (DBT; see Miller, Rathus, & Linehan, 2007, for applying DBT to adolescents) extremely useful in my practice running a general adolescent unit; similarly, the understanding of the different information processing and learning principles associated with each of the Type A and C attachment strategies, as understood in dynamic maturational model (DMM), has guided me through the dark corners of treatment. Specifically, how does DMM inform practice of DBT? As a 'DBTer' might say, 'Where is the wisdom in both points of view?' Nevertheless, DMM is not primarily about treatment. It concerns how different ways of adapting to developmental contingencies bias perceptual propensities, and hence the information available for reflective brain function. Recognition of these twists to knowing what is going on can then be used to inform a variety of therapeutic approaches. The purpose of this article is to look for the signposts in DBT and DMM which together help navigate the comprehensive approach necessary in complicated therapy. In the process, hopefully some more general principles for addressing discomfited adolescents arise for informing future practice. Although many steer shy of using personality disorder diagnoses for adolescents, clinicians are nevertheless addressing, directly or indirectly, the personality development of all adolescents in treatment, regardless of their classical axis I diagnoses, including both those with developing emotional instability and a group of avoidant over-controlled adolescents, which in Norway is growing in prominence. PMID:25410887

  5. Preferential formation of 13C- 18O bonds in carbonate minerals, estimated using first-principles lattice dynamics

    NASA Astrophysics Data System (ADS)

    Schauble, Edwin A.; Ghosh, Prosenjit; Eiler, John M.

    2006-05-01

    Equilibrium constants for internal isotopic exchange reactions of the type: Ca12C18O16O2+Ca13C16O3↔Ca13C18O16O2+Ca12C16O3 for individual CO 32- groups in the carbonate minerals calcite (CaCO 3), aragonite (CaCO 3), dolomite (CaMg(CO 3) 2), magnesite (MgCO 3), witherite (BaCO 3), and nahcolite (NaHCO 3) are calculated using first-principles lattice dynamics. Calculations rely on density functional perturbation theory (DFPT) with norm-conserving planewave pseudopotentials to determine the vibrational frequencies of isotopically substituted crystals. Our results predict an ˜0.4‰ excess of 13C18O16O22- groups in all studied carbonate minerals at room-temperature equilibrium, relative to what would be expected in a stochastic mixture of carbonate isotopologues with the same bulk 13C/ 12C, 18O/ 16O, and 17O/ 16O ratios. The amount of excess 13C18O16O22- decreases with increasing temperature of equilibration, from 0.5‰ at 0 °C to <0.1‰ at 300 °C, suggesting that measurements of multiply substituted isotopologues of carbonate could be used to infer temperatures of ancient carbonate mineral precipitation and alteration events, even where the δ 18O of coexisting fluids is uncertain. The predicted temperature sensitivity of the equilibrium constant is ˜0.003‰/°C at 25 °C. Estimated equilibrium constants for the formation of 13C18O16O22- are remarkably uniform for the variety of minerals studied, suggesting that temperature calibrations will also be applicable to carbonate minerals not studied here without greatly compromising accuracy. A related equilibrium constant for the reaction: Ca12C18O16O2+Ca12C17O16O2↔Ca12C18O17O16O+Ca12C16O3 in calcite indicates formation of 0.1‰ excess 12C 18O 17O 16O 2- at 25 °C. In a conventional phosphoric acid reaction of carbonate to form CO 2 for mass-spectrometric analysis, molecules derived from 13C18O16O22- dominate (˜96%) the mass 47 signal, and 12C 18O 17O 16O 2- contributes most of the remainder (3%). This suggests

  6. Dynamic stabilization of a bistable suspension system attached to a flexible host structure for operational safety enhancement

    NASA Astrophysics Data System (ADS)

    Yang, Kai; Harne, R. L.; Wang, K. W.; Huang, Hai

    2014-12-01

    In engineering applications, a suspension system may be attached to a flexible host structure, e.g. spacecraft truss, to provide vibration isolation for sensitive instrumentation, where the suspension and host structure dynamics are strongly coupled. For linear suspensions, a resonance normally occurs adjacent to the roll-off frequency band, which significantly and detrimentally amplifies vibration transmission. To avoid the adverse resonance for operational safety enhancement, this research proposes a nonlinear bistable suspension and evaluates its performance when attached to a flexible host structure. Dynamic models of the bistable and comparable linear suspensions attached to the host structure are formulated, and steady-state responses are predicted using analytical and numerical methods. Results show that the bistable suspension can eliminate the harmful resonance via a dynamic stabilization phenomenon, and simultaneously retains the favorable isolation performance in the roll-off bandwidth as compared to the linear suspension. Series of experimental investigations support the analytical and numerical findings and help define design guidelines for operational safety improvement.

  7. An Application of Attachment Theory: Mentoring Relationship Dynamics and Ethical Concerns

    ERIC Educational Resources Information Center

    Gormley, Barbara

    2008-01-01

    In this theoretical paper, mentoring relationships are conceptualized as close relationships that occur along a spectrum from highly functional to highly dysfunctional, with most occurring in between. A complex set of factors describe the functioning level of mentoring relationships: (a) the attachment styles of the mentors and mentees; (b)…

  8. Controlled CO preferential oxidation

    DOEpatents

    Meltser, M.A.; Hoch, M.M.

    1997-06-10

    Method is described for controlling the supply of air to a PROX (PReferential OXidation for CO cleanup) reactor for the preferential oxidation in the presence of hydrogen wherein the concentration of the hydrogen entering and exiting the PROX reactor is monitored, the difference there between correlated to the amount of air needed to minimize such difference, and based thereon the air supply to the PROX reactor adjusted to provide such amount and minimize such difference. 2 figs.

  9. Effects of temperature and isotopic substitution on electron attachment dynamics of guanine-cytosine base pair: Ring-polymer and classical molecular dynamics simulations

    NASA Astrophysics Data System (ADS)

    Minoshima, Yusuke; Seki, Yusuke; Takayanagi, Toshiyuki; Shiga, Motoyuki

    2016-06-01

    The dynamical process of electron attachment to a guanine-cytosine pair in the normal (h-GC) and deuterated (d-GC) forms has been studied theoretically by semiclassical ring-polymer molecular dynamics (RPMD) simulations using the empirical valence bond model. The initially formed dipole-bound anion is converted rapidly to the valence-bound anion within about 0.1 ps in both h-GC and d-GC. However, the subsequent proton transfer in h-GC occurs with a rate five times greater than the deuteron transfer in d-GC. The change of rates with isotopic substitution and temperature variation in the RPMD simulations are quantitatively and qualitatively different from those in the classical molecular dynamics (MD) simulations, demonstrating the importance of nuclear quantum effects on the dynamics of this system.

  10. Assessing the family dynamics of childhood maltreatment history with the Childhood Attachment and Relational Trauma Screen (CARTS)

    PubMed Central

    Frewen, Paul; Brown, Matthew; DePierro, Jonathan; D'Andrea, Wendy; Schore, Allan

    2015-01-01

    Background Existing survey measures of childhood trauma history generally fail to take into account the relational-socioecological environment in which childhood maltreatment occurs. Variables such as the relationship between the perpetrator and the victim, the emotional availability of caregivers, witnessing the abuse of others, and the respondent's own thoughts, feelings, and actions in response to maltreatment are rarely assessed by current measures. Methods To address these concerns, the current study further investigated the family dynamics of childhood maltreatment using the Childhood Attachment and Relational Trauma Screen (CARTS) in 1,782 persons assessed online. Results Paired differences in means between item-rated descriptiveness of self, mothers, and fathers suggested that respondents’ relationship with their biological fathers was less positive and secure than their relationship with their biological mothers, and that biological fathers were more often the perpetrator of emotional, physical, and sexual abuse than biological mothers. However, results further suggested that ratings between self, mothers, and fathers were positively correlated such that, for example, reports of a mother's or a respondent's own abusive behavior were more likely in the presence of reports of a father's abusive behavior. In addition, analyses evaluating witnessing violence demonstrated that fathers were rated as more often violent toward mothers than the reverse, although intimate partner violence was also frequently bidirectional. Analyses of sibling ratings further demonstrated that older brothers were either as or more frequently abusive when compared with parents. Finally, results suggested that childhood emotional, physical, and sexual abuse were much more often perpetrated by family members than extra-familial and non-family members. Conclusions In so far as these findings are consistent with the prior childhood trauma and attachment literature, the current study

  11. Theoretical Study on the Dynamic Behavior of a Plate-Like Micro-Cantilever with Multiple Particles Attached.

    PubMed

    Zhao, Liang; Wang, Fei; Zhang, YanLing; Zhao, Xuezeng

    2016-01-01

    In this study, the dynamic characteristics of a plate-like micro-cantilever beam attached with multiple concentrated masses are studied. The vibration modes of the cantilever plate are represented by combinations of beam functions. Using classical mechanics (the effect of size is not considered) and the corrected Cosserat's theorem (the effect of size is considered), we employ the Lagrange equations to establish a dynamic model of the plate-like micro-cantilever beam attached with multiple concentrated masses. The accuracy of the model proposed in this paper is verified by comparing with the results of published literature. Then, the natural frequencies of the cantilever plates are calculated with self-compiled algorithms, and the results of the plates with 1-5 masses are displayed. The results are in high accordance with the exact solution, and all errors are within 0.5%. The analysis shows that the proposed model and analysis method converges quickly and is highly efficient. In addition, the effects of characteristic lengths, Poisson's ratios and plate thickness on the micro-cantilever plate's resonant frequency for the first five modes are analyzed. PMID:27023056

  12. Theoretical Study on the Dynamic Behavior of a Plate-Like Micro-Cantilever with Multiple Particles Attached

    PubMed Central

    Zhao, Liang; Wang, Fei; Zhang, YanLing; Zhao, Xuezeng

    2016-01-01

    In this study, the dynamic characteristics of a plate-like micro-cantilever beam attached with multiple concentrated masses are studied. The vibration modes of the cantilever plate are represented by combinations of beam functions. Using classical mechanics (the effect of size is not considered) and the corrected Cosserat’s theorem (the effect of size is considered), we employ the Lagrange equations to establish a dynamic model of the plate-like micro-cantilever beam attached with multiple concentrated masses. The accuracy of the model proposed in this paper is verified by comparing with the results of published literature. Then, the natural frequencies of the cantilever plates are calculated with self-compiled algorithms, and the results of the plates with 1–5 masses are displayed. The results are in high accordance with the exact solution, and all errors are within 0.5%. The analysis shows that the proposed model and analysis method converges quickly and is highly efficient. In addition, the effects of characteristic lengths, Poisson's ratios and plate thickness on the micro-cantilever plate’s resonant frequency for the first five modes are analyzed. PMID:27023056

  13. A Jungian contribution to a dynamic systems understanding of disorganized attachment.

    PubMed

    Carter, Linda

    2011-06-01

    This panel emerged from shared clinical concerns when working with adult patients whose presentation style was reminiscent of a disorganized (Type D) infant attachment pattern. Psychotherapeutic work with such patients poses complicated transference and countertransference dilemmas which are addressed by all four panellists via theory and clinical vignettes. In common is an interest in contemporary attachment, neuroscience and trauma theories and their relationship to analytical psychology. Intergenerational trauma seems to be a salient factor in the evolution of fragmented and fragmenting interactions that lead to failures in self-coherence and healthy interpersonal relationships. Such early relational trauma is compounded by further episodes of abuse and neglect leading to failure in a core sense of self. These clinicians share how they have integrated theory and practice in order to help dissociated and disorganized patients to transform their dark and extraordinary suffering through implicit and explicit experiences with the analyst into new, life giving patterns of relationship with self and others. The alchemy of transformation, both positive and negative, is evident in the case material presented. PMID:21675978

  14. Controlled CO preferential oxidation

    DOEpatents

    Meltser, Mark A.; Hoch, Martin M.

    1997-01-01

    Method for controlling the supply of air to a PROX reactor for the preferential oxidation in the presence of hydrogen wherein the concentration of the hydrogen entering and exiting the PROX reactor is monitored, the difference therebetween correlated to the amount of air needed to minimize such difference, and based thereon the air supply to the PROX reactor adjusted to provide such amount and minimize such difference.

  15. Time-resolved radiation chemistry: Dynamics of electron attachment to uracil following UV excitation of iodide-uracil complexes

    SciTech Connect

    King, Sarah B.; Yandell, Margaret A.; Stephansen, Anne B.; Neumark, Daniel M.

    2014-12-14

    Electron attachment to uracil was investigated by applying time-resolved photoelectron imaging to iodide-uracil (I{sup –}U) complexes. In these studies, an ultraviolet pump pulse initiated charge transfer from the iodide to the uracil, and the resulting dynamics of the uracil temporary negative ion were probed. Five different excitation energies were used, 4.00 eV, 4.07 eV, 4.14 eV, 4.21 eV, and 4.66 eV. At the four lowest excitation energies, which lie near the vertical detachment energy of the I{sup –}U complex (4.11 eV), signatures of both the dipole bound (DB) as well as the valence bound (VB) anion of uracil were observed. In contrast, only the VB anion was observed at 4.66 eV, in agreement with previous experiments in this higher energy range. The early-time dynamics of both states were highly excitation energy dependent. The rise time of the DB anion signal was ∼250 fs at 4.00 eV and 4.07 eV, ∼120 fs at 4.14 eV and cross-correlation limited at 4.21 eV. The VB anion rise time also changed with excitation energy, ranging from 200 to 300 fs for excitation energies 4.00–4.21 eV, to a cross-correlation limited time at 4.66 eV. The results suggest that the DB state acts as a “doorway” state to the VB anion at 4.00–4.21 eV, while direct attachment to the VB anion occurs at 4.66 eV.

  16. Methods for Dynamic Investigations of Surface-Attached In Vitro Bacterial and Fungal Biofilms

    PubMed Central

    Sternberg, Claus; Bjarnsholt, Thomas; Shirtliff, Mark

    2015-01-01

    Three dynamic models for the investigation of in vitro biofilm formation are described in this chapter. In the 6-well plate assay presented here, the placing of the plate on a rotating platform provides shear, thereby making the system dynamic with respect to the static microtiter assay. The second reported model, especially suitable for harvesting high amounts of cells for transcriptomic or proteomic investigations, is based on numerous glass beads placed in a flask incubated with shaking on a rotating platform, thus increasing the surface area for biofilm formation. Finally, the flow-cell system, that is the driving model for elucidating the biofilm-forming process in vitro as well as the biofilm tolerance towards antibiotics and host defense components, is illustrated here. PMID:24664822

  17. Metastable anions of polyynes: Dynamics of fragmentation/stabilization in planetary atmospheres after electron attachment

    NASA Astrophysics Data System (ADS)

    Sebastianelli, F.; Gianturco, F. A.

    2012-02-01

    The quantum dynamics of low-energy free electrons colliding with linear carbonaceous species like HC3N and HC5N is examined to identify the locations and structural features of their metastable negative ions (resonant compound states of the colliding partners) with the aim of suggesting, at the molecular level, the possible mechanisms of anionic stabilization which lead to the several stable species observed in the interstellar and circumstellar media in connection with polyyne structures.

  18. Information filtering via preferential diffusion

    NASA Astrophysics Data System (ADS)

    Lü, Linyuan; Liu, Weiping

    2011-06-01

    Recommender systems have shown great potential in addressing the information overload problem, namely helping users in finding interesting and relevant objects within a huge information space. Some physical dynamics, including the heat conduction process and mass or energy diffusion on networks, have recently found applications in personalized recommendation. Most of the previous studies focus overwhelmingly on recommendation accuracy as the only important factor, while overlooking the significance of diversity and novelty that indeed provide the vitality of the system. In this paper, we propose a recommendation algorithm based on the preferential diffusion process on a user-object bipartite network. Numerical analyses on two benchmark data sets, MovieLens and Netflix, indicate that our method outperforms the state-of-the-art methods. Specifically, it can not only provide more accurate recommendations, but also generate more diverse and novel recommendations by accurately recommending unpopular objects.

  19. Information filtering via preferential diffusion.

    PubMed

    Lü, Linyuan; Liu, Weiping

    2011-06-01

    Recommender systems have shown great potential in addressing the information overload problem, namely helping users in finding interesting and relevant objects within a huge information space. Some physical dynamics, including the heat conduction process and mass or energy diffusion on networks, have recently found applications in personalized recommendation. Most of the previous studies focus overwhelmingly on recommendation accuracy as the only important factor, while overlooking the significance of diversity and novelty that indeed provide the vitality of the system. In this paper, we propose a recommendation algorithm based on the preferential diffusion process on a user-object bipartite network. Numerical analyses on two benchmark data sets, MovieLens and Netflix, indicate that our method outperforms the state-of-the-art methods. Specifically, it can not only provide more accurate recommendations, but also generate more diverse and novel recommendations by accurately recommending unpopular objects. PMID:21797453

  20. Mechanisms of oriented attachment of TiO2 nanocrystals in vacuum and humid environments: reactive molecular dynamics.

    PubMed

    Raju, Muralikrishna; van Duin, Adri C T; Fichthorn, Kristen A

    2014-01-01

    Oriented attachment (OA) of nanocrystals is now widely recognized as a key process in the solution-phase growth of hierarchical nanostructures. However, the microscopic origins of OA remain unclear. We perform molecular dynamics simulations using a recently developed ReaxFF reactive force field to study the aggregation of various titanium dioxide (anatase) nanocrystals in vacuum and humid environments. In vacuum, the nanocrystals merge along their direction of approach, resulting in a polycrystalline material. By contrast, in the presence of water vapor the nanocrystals reorient themselves and aggregate via the OA mechanism to form a single or twinned crystal. They accomplish this by creating a dynamic network of hydrogen bonds between surface hydroxyls and surface oxygens of aggregating nanocrystals. We determine that OA is dominant on surfaces that have the greatest propensity to dissociate water. Our results are consistent with experiment, are likely to be general for aqueous oxide systems, and demonstrate the critical role of solvent in nanocrystal aggregation. This work opens up new possibilities for directing nanocrystal growth to fabricate nanomaterials with desired shapes and sizes. PMID:24601782

  1. Evolution of attached and detached slabs and their associated mantle dynamics

    NASA Technical Reports Server (NTRS)

    Hsui, Albert T.

    1992-01-01

    possibly an upward rotation of the slab such that smaller dip angles are formed. Seismic studies of the Japanese Slab seem to support this interpretation. The development of oroclinal geometries at convergent boundaries was also examined to study plate obduction which is an important ingredient to the initiation of plate subduction. Although the study suggests that surface features are better modeled by block models, the large scale deformation can be adequately studied by viscous models. Such a model is now under development to complete our original objective to study the initiation of plate subduction. Finally, a three-dimensional, finite element, spherical convective model is developed to study dynamic plate subductions. The model development is now complete and it is being tested to ensure its proper operation. The model is able to generate convection results with a viscosity contrast of about 100. Our research continues to push the viscosity contrast to a level that is appropriate for a subducting slab.

  2. Three cotton genes preferentially expressed in flower tissues encode actin-depolymerizing factors which are involved in F-actin dynamics in cells

    PubMed Central

    Li, Xue-Bao; Xu, Dan; Wang, Xiu-Lan; Huang, Geng-Qing; Luo, Juan; Li, Deng-Di; Zhang, Ze-Ting; Xu, Wen-Liang

    2010-01-01

    To investigate whether the high expression levels of actin-depolymerizing factor genes are related to pollen development, three GhADF genes (cDNAs) were isolated and characterized in cotton. Among them, GhADF6 and GhADF8 were preferentially expressed in petals, whereas GhADF7 displayed the highest level of expression in anthers, revealing its anther specificity. The GhADF7 transcripts in anthers reached its peak value at flowering, suggesting that its expression is developmentally-regulated in anthers. The GhADF7 gene including the promoter region was isolated from the cotton genome. To demonstrate the specificity of the GhADF7 promoter, the 5′-flanking region, including the promoter and 5′-untranslated region, was fused with the GUS gene. Histochemical assays demonstrated that the GhADF7:GUS gene was specifically expressed in pollen grains. When pollen grains germinated, very strong GUS staining was detected in the elongating pollen tube. Furthermore, overexpression of GhADF7 gene in Arabidopsis thaliana reduced the viable pollen grains and, consequently, transgenic plants were partially male-sterile. Overexpression of GhADF7 in fission yeast (Schizosaccharomyces pombe) altered the balance of actin depolymerization and polymerization, leading to the defective cytokinesis and multinucleate formation in the cells. Given all the above results together, it is proposed that the GhADF7 gene may play an important role in pollen development and germination. PMID:19861654

  3. Attachment Disorganization.

    ERIC Educational Resources Information Center

    Solomon, Judith, Ed.; George, Carol, Ed.

    Disorganized attachment relationships were first formally identified on the basis of the anomalous behavior of some infants during laboratory separations and reunions with the parent. This book presents new research and theory on the topic of attachment disorganization, an area of investigation that is of increasing importance in the study of…

  4. Preferential Remedies for Employment Discrimination

    ERIC Educational Resources Information Center

    Edwards, Harry T.; Zaretsky, Barry L.

    1975-01-01

    An overview of the problem of preferential remedies to achieve equal employment opportunities for women and minority groups. Contends that "color blindness" will not end discrimination but that some form of "color conscious" affirmative action program must be employed. Temporary preferential treatment is justified, according to the author, by the…

  5. Characterization of the estrogen receptor and its dynamics in MCF-7 human breast cancer cells using a covalently attaching antiestrogen

    SciTech Connect

    Monsma, F.J. Jr.; Katzenellenbogen, B.S.; Miller, M.A.; Ziegler, Y.S.; Katzenellenbogen, J.A.

    1984-07-01

    The authors have used a covalently attaching antiestrogen, tamoxifen aziridine TA to analyze the structure and dynamics of the estrogen receptor in MCF-7 human breast cancer cells. The labeling of receptor with (/sup 3/H)TA is specific, being blocked only by estrogens and antiestrogens, and the labeling is very efficient in that TA labels covalently the same number of receptors that are labeled reversibly by estradiol. In cells exposed to (/sup 3/H)TA for 1 h, most of the covalently associated radioactivity is found in the 0.6 M KCl extract of the nuclear fraction; this receptor has an apparent mol wt of 63,000 +/- 2000 by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and a pI of 5.7 by gel isoelectric focusing in the presence of 8 M urea. The mol wt and pI of cytosol receptor labeled with (/sup 3/H) TA are identical. In cells labeled with (/sup 3/H)TA (20 nM) for 1 h and then exposed to a chase of 10(-6) M estradiol, (3H)TA-labeled nuclear receptor disappears with a half-life of 4 h. Affinity labeled receptor interacts with several monoclonal antibodies to MCF-7 estrogen receptor, and it can be purified extensively by immunoadsorbent chromatography. The findings of similar mol wt and isoelectric points for soluble cytosol and nuclear extracted receptors under strongly denaturing and disaggregating conditions reveal that nuclear localization of receptor after ligand binding is not associated with major structural alterations in the receptor component labeled by TA.

  6. Spindly attachments

    PubMed Central

    Çivril, Filiz; Musacchio, Andrea

    2008-01-01

    The attachment of chromosomes to spindle microtubules during mitosis is a delicate and intricate process on which eukaryotic cells critically depend to maintain their ploidy. In this issue of Genes & Development, Gassmann and colleagues (pp. 2385–2399 present an analysis of the recently discovered Spindly/SPDL-1 protein that casts new lights onto the attachment process and the way it relates to the control of cell cycle progression. PMID:18765786

  7. Preferential Nucleation during Polymorphic Transformations

    PubMed Central

    Sharma, H.; Sietsma, J.; Offerman, S. E.

    2016-01-01

    Polymorphism is the ability of a solid material to exist in more than one phase or crystal structure. Polymorphism may occur in metals, alloys, ceramics, minerals, polymers, and pharmaceutical substances. Unresolved are the conditions for preferential nucleation during polymorphic transformations in which structural relationships or special crystallographic orientation relationships (OR’s) form between the nucleus and surrounding matrix grains. We measured in-situ and simultaneously the nucleation rates of grains that have zero, one, two, three and four special OR’s with the surrounding parent grains. These experiments show a trend in which the activation energy for nucleation becomes smaller – and therefore nucleation more probable - with increasing number of special OR’s. These insights contribute to steering the processing of polymorphic materials with tailored properties, since preferential nucleation affects which crystal structure forms, the average grain size and texture of the material, and thereby - to a large extent - the final properties of the material. PMID:27484579

  8. Preferential Nucleation during Polymorphic Transformations

    NASA Astrophysics Data System (ADS)

    Sharma, H.; Sietsma, J.; Offerman, S. E.

    2016-08-01

    Polymorphism is the ability of a solid material to exist in more than one phase or crystal structure. Polymorphism may occur in metals, alloys, ceramics, minerals, polymers, and pharmaceutical substances. Unresolved are the conditions for preferential nucleation during polymorphic transformations in which structural relationships or special crystallographic orientation relationships (OR’s) form between the nucleus and surrounding matrix grains. We measured in-situ and simultaneously the nucleation rates of grains that have zero, one, two, three and four special OR’s with the surrounding parent grains. These experiments show a trend in which the activation energy for nucleation becomes smaller – and therefore nucleation more probable - with increasing number of special OR’s. These insights contribute to steering the processing of polymorphic materials with tailored properties, since preferential nucleation affects which crystal structure forms, the average grain size and texture of the material, and thereby - to a large extent - the final properties of the material.

  9. Preferential Nucleation during Polymorphic Transformations.

    PubMed

    Sharma, H; Sietsma, J; Offerman, S E

    2016-01-01

    Polymorphism is the ability of a solid material to exist in more than one phase or crystal structure. Polymorphism may occur in metals, alloys, ceramics, minerals, polymers, and pharmaceutical substances. Unresolved are the conditions for preferential nucleation during polymorphic transformations in which structural relationships or special crystallographic orientation relationships (OR's) form between the nucleus and surrounding matrix grains. We measured in-situ and simultaneously the nucleation rates of grains that have zero, one, two, three and four special OR's with the surrounding parent grains. These experiments show a trend in which the activation energy for nucleation becomes smaller - and therefore nucleation more probable - with increasing number of special OR's. These insights contribute to steering the processing of polymorphic materials with tailored properties, since preferential nucleation affects which crystal structure forms, the average grain size and texture of the material, and thereby - to a large extent - the final properties of the material. PMID:27484579

  10. Preferred Attachment in Affiliation Networks

    NASA Astrophysics Data System (ADS)

    Bloznelis, Mindaugas; Götze, Friedrich

    2014-08-01

    Vertices of an affiliation network are linked to attributes and two vertices are declared adjacent whenever they share a common attribute. For example, two customers of an internet shop (or video-sharing website) are called adjacent if they have purchased (or downloaded) the same or similar items. Assuming that each newly arrived customer is linked preferentially to already popular items we obtain a preferred attachment affiliation network that evolves in time. We show that the fraction of customers having neighbours scales as for large . Here is the ratio between the two intensities: intensity of the flow of customers and that of the newly arriving items.

  11. A study of the dynamics of rotating space stations with elastically connected counterweight and attached flexible appendages. Volume 1: Theory

    NASA Technical Reports Server (NTRS)

    Austin, F.; Markowitz, J.; Goldenberg, S.; Zetkov, G. A.

    1973-01-01

    The formulation of a mathematical model for predicting the dynamic behavior of rotating flexible space station configurations was conducted. The overall objectives of the study were: (1) to develop the theoretical techniques for determining the behavior of a realistically modeled rotating space station, (2) to provide a versatile computer program for the numerical analysis, and (3) to present practical concepts for experimental verification of the analytical results. The mathematical model and its associated computer program are described.

  12. Effect of elevated CO2 on the dynamics of particle attached and free living bacterioplankton communities in an Arctic fjord

    NASA Astrophysics Data System (ADS)

    Sperling, M.; Piontek, J.; Gerdts, G.; Wichels, A.; Schunck, H.; Roy, A.-S.; La Roche, J.; Gilbert, J.; Bittner, L.; Romac, S.; Riebesell, U.; Engel, A.

    2012-08-01

    The increase in atmospheric carbon dioxide (CO2) results in acidification of the oceans, expected to lead to the fastest drop in ocean pH in the last 300 million years, if anthropogenic emissions are continued at present rate. Due to higher solubility of gases in cold waters and increased exposure to the atmosphere by decreasing ice cover, the Arctic Ocean will be among the areas most strongly affected by ocean acidification. Yet, the response of the plankton community of high latitudes to ocean acidification has not been studied so far. This work is part of the Arctic campaign of the European Project on Ocean Acidification (EPOCA) in 2010, employing 9 in situ mesocosms of about 45 000 l each to simulate ocean acidification in Kongsfjorden, Svalbard (78°56.2' N 11°53.6' E). In the present study, we investigated effects of elevated CO2 on the composition and richness of particle attached (PA; >3 μm) and free living (FL; <3 μm >0.2 μm) bacterial communities by Automated Ribosomal Intergenic Spacer Analysis (ARISA) in 6 of the mesocosms and the surrounding fjord, ranging from 185 to 1050 initial μatm pCO2. ARISA was able to resolve about 20-30 bacterial band-classes per sample and allowed for a detailed investigation of the explicit richness. Both, the PA and the FL bacterioplankton community exhibited a strong temporal development, which was driven mainly by temperature and phytoplankton development. In response to the breakdown of a picophytoplankton bloom (phase 3 of the experiment), number of ARISA-band classes in the PA-community were reduced at low and medium CO2 (∼180-600 μatm) by about 25%, while it was more or less stable at high CO2 (∼ 650-800 μatm). We hypothesise that enhanced viral lysis and enhanced availability of organic substrates at high CO2 resulted in a more diverse PA-bacterial community in the post-bloom phase. Despite lower cell numbers and extracellular enzyme activities in the post-bloom phase, bacterial protein production was

  13. Effect of ionic liquid on the native and denatured state of a protein covalently attached to a probe: Solvation dynamics study

    NASA Astrophysics Data System (ADS)

    Chowdhury, Rajdeep; Mojumdar, Supratik Sen; Chattoraj, Shyamtanu; Bhattacharyya, Kankan

    2012-08-01

    Effect of a room temperature ionic liquid (RTIL, [pmim][Br]) on the solvation dynamics of a probe covalently attached to a protein (human serum albumin (HSA)) has been studied using femtosecond up-conversion. For this study, a solvation probe, 7-diethylamino-3-(4-maleimidophenyl)-4-methylcoumarin (CPM) has been covalently attached to the lone cysteine group (cys-34) of the protein HSA. Addition of 1.5 M RTIL or 6 M GdnHCl causes a red shift of the emission maxima of CPM bound to HSA by 3 nm and 12 nm, respectively. The average solvation time ⟨τs⟩ decreases from 650 ps (in native HSA) to 260 ps (˜2.5 times) in the presence of 1.5 M RTIL and to 60 ps (˜11 times) in the presence of 6 M GdnHCl. This is ascribed to unfolding of the protein by RTIL or GdnHCl and therefore making the probe CPM more exposed. When 1.5 M RTIL is added to the protein denatured by 6 M GdnHCl in advance, a further ˜5 nm red shift along with further ˜2 fold faster solvent relaxation (⟨τ⟩ ˜30 ps) is observed. Our previous fluorescence correlation spectroscopy study [D. K. Sasmal, T. Mondal, S. Sen Mojumdar, A. Choudhury, R. Banerjee, and K. Bhattacharyya, J. Phys. Chem. B 115, 13075 (2011), 10.1021/jp207829y] suggests that addition of RTIL to the protein denatured by 6 M GdnHCl causes a reduction in hydrodynamic radius (rh). It is demonstrated that in the presence of RTIL and GdnHCl, though the protein is structurally more compact, the local environment of CPM is very different from that in the native state.

  14. Paternal Attachment, Parenting Beliefs and Children's Attachment

    ERIC Educational Resources Information Center

    Howard, Kimberly S.

    2010-01-01

    Relationships between fathers' romantic attachment style, parenting beliefs and father-child attachment security and dependence were examined in a diverse sample of 72 fathers of young children. Paternal romantic attachment style was coded based on fathers' endorsement of a particular style represented in the Hazan and Shaver Three-Category…

  15. 15 CFR 700.14 - Preferential scheduling.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...) BUREAU OF INDUSTRY AND SECURITY, DEPARTMENT OF COMMERCE NATIONAL SECURITY INDUSTRIAL BASE REGULATIONS DEFENSE PRIORITIES AND ALLOCATIONS SYSTEM Industrial Priorities § 700.14 Preferential scheduling. (a)...

  16. Wikipedia editing dynamics

    NASA Astrophysics Data System (ADS)

    Gandica, Y.; Carvalho, J.; Sampaio dos Aidos, F.

    2015-01-01

    A model for the probabilistic function followed in editing Wikipedia is presented and compared with simulations and real data. It is argued that the probability of editing is proportional to the editor's number of previous edits (preferential attachment), to the editor's fitness, and to an aging factor. Using these simple ingredients, it is possible to reproduce the results obtained for Wikipedia editing dynamics for a collection of single pages as well as the averaged results. Using a stochastic process framework, a recursive equation was obtained for the average of the number of edits per editor that seems to describe the editing behavior in Wikipedia.

  17. Wikipedia editing dynamics.

    PubMed

    Gandica, Y; Carvalho, J; Sampaio Dos Aidos, F

    2015-01-01

    A model for the probabilistic function followed in editing Wikipedia is presented and compared with simulations and real data. It is argued that the probability of editing is proportional to the editor's number of previous edits (preferential attachment), to the editor's fitness, and to an aging factor. Using these simple ingredients, it is possible to reproduce the results obtained for Wikipedia editing dynamics for a collection of single pages as well as the averaged results. Using a stochastic process framework, a recursive equation was obtained for the average of the number of edits per editor that seems to describe the editing behavior in Wikipedia. PMID:25679673

  18. Understanding and promoting attachment.

    PubMed

    Wilson, Samantha L

    2009-08-01

    Interest in early relationships has led to increased use of terms such as attachment disorder, attachment problems, and attachment therapy when describing behavioral/emotional regulation in young children. Unfortunately, such terms are vague and lead to clinical confusion and diagnostic inaccuracies. This article will introduce attachment theory, with a discussion of reactive attachment disorder and implications for treatment of children who have problems with social-emotional development. PMID:19681518

  19. Reversal of flagellar rotation is important in initial attachment of Escherichia coli to glass in a dynamic system with high- and low-ionic-strength buffers.

    PubMed

    McClaine, Jennifer W; Ford, Roseanne M

    2002-03-01

    The attachment rates of wild-type, smooth-swimming, tumbly, and paralyzed Escherichia coli to glass was measured at fluid velocities of 0.0044 and 0.044 cms(-1) (corresponding to shear rates of 0.34 and 3.4 s(-1), respectively), in 0.02 and 0.2 M buffer solutions. At the highest ionic strength, we did not observe a significant difference in the attachment rate of wild-type and paralyzed cells at either fluid velocity. However, when the ionic strength was reduced, paralyzed bacteria attached at rates 4 and 10 times lower than that of the wild type under fluid velocities of 0.0044 and 0.044 cms(-1), respectively. This suggested that the rotation of the flagella assisted in attachment. We then compared the attachment rates of smooth-swimming (counterclockwise rotation only) and tumbly (clockwise rotation only) cells to the wild type to determine whether the direction of rotation was important to cell attachment. At 0.0044 cms(-1), the smooth-swimming cells attached at rates similar to that of the wild type in both buffer solutions but significantly less at the higher fluid velocity. Tumbly cells attached at much lower rates under all conditions. Thus, the combination of clockwise and counterclockwise flagellar rotation and their coupling appeared to be important in cell attachment. We considered a number of hypotheses to interpret these observations, including a residence time analysis and a comparison of traditional Derjaguin-Landau-Verwey-Overbeek (DLVO) theory to soft-particle theory. PMID:11872478

  20. Electron attachment to fluorocarbon radicals

    NASA Astrophysics Data System (ADS)

    Shuman, Nicholas

    2014-10-01

    Most plasma environments contain populations of short-lived species such as radicals, the chemistry of which can have significant effects on the overall chemistry of the system. However, few experimental measurements of the kinetics of electron attachment to radicals exist due to the inherent difficulties of working with transient species. Calculations from first principles have been attempted, but are arduous and, because electron attachment is so sensitive to the specifics of the potential surface, their accuracy has not been established. Electron attachment to small fluorocarbon radicals is particularly important, as the data are needed for predictive modeling of plasma etching of semiconductor materials, a key process in the industrial fabrication of microelectronics. We have recently developed a novel flowing afterglow technique to measure several types of otherwise difficult to study plasma processes, including thermal electron attachment to radicals. Variable Electron and Neutral Density Attachment Mass Spectrometry (VENDAMS) exploits dissociative electron attachment in a weakly ionized plasma as a radical source. Here, we apply VENDAMS to a series of halofluorocarbon precursors in order to measure the kinetics of thermal electron attachment to fluorocarbon radicals. Results are presented for CF2, CF3, C2F5,C2F3,1-C3F7, 2-C3F7, and C3F5 from 300 K to 900 K. Both the magnitude and the temperature dependences of rate coefficients as well as product branching between associative and dissociative attachment are highly system specific; however, thermal attachment to all species is inefficient, never exceeding 5% of the collision rate. The data are analyzed using a recently developed kinetic modeling approach, which uses extended Vogt-Wannier theory as a starting point, accounts for dynamic effects such as coupling between the electron and nuclear motions through empirically validated functional forms, and finally uses statistical theory to determine the fate of

  1. Belt attachment and system

    DOEpatents

    Schneider, Abraham D.; Davidson, Erick M.

    2016-02-02

    Disclosed herein is a belt assembly including a flexible belt with an improved belt attachment. The belt attachment includes two crossbars spaced along the length of the belt. The crossbars retain bearings that allow predetermined movement in six degrees of freedom. The crossbars are connected by a rigid body that attaches to the bearings. Implements that are attached to the rigid body are simply supported but restrained in pitching rotation.

  2. Adolescent Attachment and Psychopathology.

    ERIC Educational Resources Information Center

    Rosenstein, Diana S.; Horowitz, Harvey A.

    1996-01-01

    In relationships among attachment classification, psychopathology, and personality, traits were examined in a group of 60 psychiatrically hospitalized adolescents. Attachment was examined in 27 adolescent-mother pairs. Both adolescent and maternal attachment status were overwhelmingly insecure and were highly concordant. Results support a model of…

  3. Special Attachments. Module 19.

    ERIC Educational Resources Information Center

    South Carolina State Dept. of Education, Columbia. Office of Vocational Education.

    This module on special attachments, one in a series dealing with industrial sewing machines, their attachments, and operation, covers four topics: gauges; cording attachment; zipper foot; and hemming, shirring, and binding. For each topic these components are provided: an introduction, directions, an objective, learning activities, student…

  4. Neurobiology of infant attachment.

    PubMed

    Moriceau, Stephanie; Sullivan, Regina M

    2005-11-01

    A strong attachment to the caregiver is critical for survival in altricial species, including humans. While some behavioral aspects of attachment have been characterized, its neurobiology has only recently received attention. Using a mammalian imprinting model, we are assessing the neural circuitry that enables infant rats to attach quickly to a caregiver, thus enhancing survival in the nest. Specifically, the hyper-functioning noradrenergic locus coeruleus (LC) enables pups to learn rapid, robust preference for the caregiver. Conversely, a hypo-functional amygdala appears to prevent the infant from learning aversions to the caregiver. Adult LC and amygdala functional emergence correlates with sensitive period termination. This study suggests the neonatal brain is not an immature version of the adult brain but is uniquely designed to optimize attachment to the caregiver. Although human attachment may not rely on identical circuitry, the work reviewed here suggests a new conceptual framework in which to explore human attachments, particularly attachments to abusive caregivers. PMID:16252291

  5. Submicron structures provide preferential spots for carbon and nitrogen sequestration in soils

    PubMed Central

    Vogel, Cordula; Mueller, Carsten W.; Höschen, Carmen; Buegger, Franz; Heister, Katja; Schulz, Stefanie; Schloter, Michael; Kögel-Knabner, Ingrid

    2014-01-01

    The sequestration of carbon and nitrogen by clay-sized particles in soils is well established, and clay content or mineral surface area has been used to estimate the sequestration potential of soils. Here, via incubation of a sieved (<2 mm) topsoil with labelled litter, we find that only some of the clay-sized surfaces bind organic matter (OM). Surprisingly, <19% of the visible mineral areas show an OM attachment. OM is preferentially associated with organo-mineral clusters with rough surfaces. By combining nano-scale secondary ion mass spectrometry and isotopic tracing, we distinguish between new labelled and pre-existing OM and show that new OM is preferentially attached to already present organo-mineral clusters. These results, which provide evidence that only a limited proportion of the clay-sized surfaces contribute to OM sequestration, revolutionize our view of carbon sequestration in soils and the widely used carbon saturation estimates. PMID:24399306

  6. Discovering Preferential Patterns in Sectoral Trade Networks.

    PubMed

    Cingolani, Isabella; Piccardi, Carlo; Tajoli, Lucia

    2015-01-01

    We analyze the patterns of import/export bilateral relations, with the aim of assessing the relevance and shape of "preferentiality" in countries' trade decisions. Preferentiality here is defined as the tendency to concentrate trade on one or few partners. With this purpose, we adopt a systemic approach through the use of the tools of complex network analysis. In particular, we apply a pattern detection approach based on community and pseudocommunity analysis, in order to highlight the groups of countries within which most of members' trade occur. The method is applied to two intra-industry trade networks consisting of 221 countries, relative to the low-tech "Textiles and Textile Articles" and the high-tech "Electronics" sectors for the year 2006, to look at the structure of world trade before the start of the international financial crisis. It turns out that the two networks display some similarities and some differences in preferential trade patterns: they both include few significant communities that define narrow sets of countries trading with each other as preferential destinations markets or supply sources, and they are characterized by the presence of similar hierarchical structures, led by the largest economies. But there are also distinctive features due to the characteristics of the industries examined, in which the organization of production and the destination markets are different. Overall, the extent of preferentiality and partner selection at the sector level confirm the relevance of international trade costs still today, inducing countries to seek the highest efficiency in their trade patterns. PMID:26485163

  7. A generalized theory of preferential linking

    NASA Astrophysics Data System (ADS)

    Hu, Haibo; Guo, Jinli; Liu, Xuan; Wang, Xiaofan

    2014-12-01

    There are diverse mechanisms driving the evolution of social networks. A key open question dealing with understanding their evolution is: How do various preferential linking mechanisms produce networks with different features? In this paper we first empirically study preferential linking phenomena in an evolving online social network, find and validate the linear preference. We propose an analyzable model which captures the real growth process of the network and reveals the underlying mechanism dominating its evolution. Furthermore based on preferential linking we propose a generalized model reproducing the evolution of online social networks, and present unified analytical results describing network characteristics for 27 preference scenarios. We study the mathematical structure of degree distributions and find that within the framework of preferential linking analytical degree distributions can only be the combinations of finite kinds of functions which are related to rational, logarithmic and inverse tangent functions, and extremely complex network structure will emerge even for very simple sublinear preferential linking. This work not only provides a verifiable origin for the emergence of various network characteristics in social networks, but bridges the micro individuals' behaviors and the global organization of social networks.

  8. Preferential sampling in veterinary parasitological surveillance.

    PubMed

    Cecconi, Lorenzo; Biggeri, Annibale; Grisotto, Laura; Berrocal, Veronica; Rinaldi, Laura; Musella, Vincenzo; Cringoli, Giuseppe; Catelan, Dolores

    2016-01-01

    In parasitological surveillance of livestock, prevalence surveys are conducted on a sample of farms using several sampling designs. For example, opportunistic surveys or informative sampling designs are very common. Preferential sampling refers to any situation in which the spatial process and the sampling locations are not independent. Most examples of preferential sampling in the spatial statistics literature are in environmental statistics with focus on pollutant monitors, and it has been shown that, if preferential sampling is present and is not accounted for in the statistical modelling and data analysis, statistical inference can be misleading. In this paper, working in the context of veterinary parasitology, we propose and use geostatistical models to predict the continuous and spatially-varying risk of a parasite infection. Specifically, breaking with the common practice in veterinary parasitological surveillance to ignore preferential sampling even though informative or opportunistic samples are very common, we specify a two-stage hierarchical Bayesian model that adjusts for preferential sampling and we apply it to data on Fasciola hepatica infection in sheep farms in Campania region (Southern Italy) in the years 2013-2014. PMID:27087037

  9. On preferential flow and its measurement

    SciTech Connect

    Luxmoore, R.J.

    1991-01-01

    Preferential flow is a useful generic term for describing the process whereby water movement through a porous medium follows favored routes bypassing other parts of the medium. This term does not give any indication of the pore scales involved. Sometimes macropore flow is used to describe preferential flow and this term implies that large pores of some sort are conductive. There is no consensus definition of what constitutes a macropore so one needs to carefully determine what is meant when that term is used. The main focus of this report is on the measurement and characterization of preferential flow through structured soils, however, preferred path flow also occurs in sandy soils. Fingering flow in soils, a result of wetting front instability, is a third type of preferential flow that occurs in porous media with more or less random pore arrangement. There may not be any physically defined channels in the soil to account for this type of flow. A larger scale flow described as funnel flow by Kung et al. (1990) results from profile heterogeneity. Low permeability layers or coarse lenses in a profile may restrict vertical drainage redirecting flow laterally through specific regions of the profile (like a funnel). Water repellency can also be a factor in the development of preferential flow. 34 refs.

  10. Reverse preferential spread in complex networks

    NASA Astrophysics Data System (ADS)

    Toyoizumi, Hiroshi; Tani, Seiichi; Miyoshi, Naoto; Okamoto, Yoshio

    2012-08-01

    Large-degree nodes may have a larger influence on the network, but they can be bottlenecks for spreading information since spreading attempts tend to concentrate on these nodes and become redundant. We discuss that the reverse preferential spread (distributing information inversely proportional to the degree of the receiving node) has an advantage over other spread mechanisms. In large uncorrelated networks, we show that the mean number of nodes that receive information under the reverse preferential spread is an upper bound among any other weight-based spread mechanisms, and this upper bound is indeed a logistic growth independent of the degree distribution.

  11. Blade attachment assembly

    DOEpatents

    Garcia-Crespo, Andres Jose; Delvaux, John McConnell; Miller, Diane Patricia

    2016-05-03

    An assembly and method for affixing a turbomachine rotor blade to a rotor wheel are disclosed. In an embodiment, an adaptor member is provided disposed between the blade and the rotor wheel, the adaptor member including an adaptor attachment slot that is complementary to the blade attachment member, and an adaptor attachment member that is complementary to the rotor wheel attachment slot. A coverplate is provided, having a coverplate attachment member that is complementary to the rotor wheel attachment slot, and a hook for engaging the adaptor member. When assembled, the coverplate member matingly engages with the adaptor member, and retains the blade in the adaptor member, and the assembly in the rotor wheel.

  12. Protein Attachment on Nanodiamonds.

    PubMed

    Lin, Chung-Lun; Lin, Cheng-Huang; Chang, Huan-Cheng; Su, Meng-Chih

    2015-07-16

    A recent advance in nanotechnology is the scale-up production of small and nonaggregated diamond nanoparticles suitable for biological applications. Using detonation nanodiamonds (NDs) with an average diameter of ∼4 nm as the adsorbents, we have studied the static attachment of three proteins (myoglobin, bovine serum albumin, and insulin) onto the nanoparticles by optical spectroscopy, mass spectrometry, and dynamic light scattering, and electrophoretic zeta potential measurements. Results show that the protein surface coverage is predominantly determined by the competition between protein-protein and protein-ND interactions, giving each protein a unique and characteristic structural configuration in its own complex. Specifically, both myoglobin and bovine serum albumin show a Langmuir-type adsorption behavior, forming 1:1 complexes at saturation, whereas insulin folds into a tightly bound multimer before adsorption. The markedly different adsorption patterns appear to be independent of the protein concentration and are closely related to the affinity of the individual proteins for the NDs. The present study provides a fundamental understanding for the use of NDs as a platform for nanomedical drug delivery. PMID:25815400

  13. A generalized distance function for preferential choices.

    PubMed

    Berkowitsch, Nicolas A J; Scheibehenne, Benjamin; Rieskamp, Jörg; Matthäus, Max

    2015-05-01

    Many cognitive theories of judgement and decision making assume that choice options are evaluated relative to other available options. The extent to which the preference for one option is influenced by other available options will often depend on how similar the options are to each other, where similarity is assumed to be a decreasing function of the distance between options. We examine how the distance between preferential options that are described on multiple attributes can be determined. Previous distance functions do not take into account that attributes differ in their subjective importance, are limited to two attributes, or neglect the preferential relationship between the options. To measure the distance between preferential options it is necessary to take the subjective preferences of the decision maker into account. Accordingly, the multi-attribute space that defines the relationship between options can be stretched or shrunk relative to the attention or importance that a person gives to different attributes describing the options. Here, we propose a generalized distance function for preferential choices that takes subjective attribute importance into account and allows for individual differences according to such subjective preferences. Using a hands-on example, we illustrate the application of the function and compare it to previous distance measures. We conclude with a discussion of the suitability and limitations of the proposed distance function. PMID:25677976

  14. The Probabilistic Nature of Preferential Choice

    ERIC Educational Resources Information Center

    Rieskamp, Jorg

    2008-01-01

    Previous research has developed a variety of theories explaining when and why people's decisions under risk deviate from the standard economic view of expected utility maximization. These theories are limited in their predictive accuracy in that they do not explain the probabilistic nature of preferential choice, that is, why an individual makes…

  15. Attachment and Early Maltreatment.

    ERIC Educational Resources Information Center

    Egeland, Byron; Sroufe, L. Alan

    1981-01-01

    Attachment outcomes of 31 maltreatment cases (involving extreme neglect or abuse), selected from a total poverty sample of 267 high-risk mothers and their children, were compared to those of a subsample of 33 cases with a history of excellent care. Attachment was assessed when infants were 12 and 18 months old. (Author/MP)

  16. Infant Feeding and Attachment.

    ERIC Educational Resources Information Center

    Ainsworth, Mary D. Salter; Tracy, Russel L.

    This paper has two major purposes: first, to consider how infant feeding behavior may fit into attachment theory; and second, to cite some evidence to show how an infant's early interaction with his mother in the feeding situation is related to subsequent development. It was found that sucking and rooting are precursor attachment behaviors that…

  17. Attachment Theory and Mindfulness

    ERIC Educational Resources Information Center

    Snyder, Rose; Shapiro, Shauna; Treleaven, David

    2012-01-01

    We initiate a dialog between two central areas in the field of psychology today: attachment theory/research and mindfulness studies. The impact of the early mother-infant relationship on child development has been well established in the literature, with attachment theorists having focused on the correlation between a mother's capacity for…

  18. Separation and Attachment

    ERIC Educational Resources Information Center

    Honig, Alice Sterling

    2005-01-01

    Developing secure attachments with babies gives them a very special gift--the foundation for good infant mental health! In this article, the author discusses how to develop secure attachments with babies. Babies who are in the care of others during the day often suffer from separations from their special adults. Thirteen "tips" to ensure that…

  19. Discovering Preferential Patterns in Sectoral Trade Networks

    PubMed Central

    Cingolani, Isabella; Piccardi, Carlo; Tajoli, Lucia

    2015-01-01

    We analyze the patterns of import/export bilateral relations, with the aim of assessing the relevance and shape of “preferentiality” in countries’ trade decisions. Preferentiality here is defined as the tendency to concentrate trade on one or few partners. With this purpose, we adopt a systemic approach through the use of the tools of complex network analysis. In particular, we apply a pattern detection approach based on community and pseudocommunity analysis, in order to highlight the groups of countries within which most of members’ trade occur. The method is applied to two intra-industry trade networks consisting of 221 countries, relative to the low-tech “Textiles and Textile Articles” and the high-tech “Electronics” sectors for the year 2006, to look at the structure of world trade before the start of the international financial crisis. It turns out that the two networks display some similarities and some differences in preferential trade patterns: they both include few significant communities that define narrow sets of countries trading with each other as preferential destinations markets or supply sources, and they are characterized by the presence of similar hierarchical structures, led by the largest economies. But there are also distinctive features due to the characteristics of the industries examined, in which the organization of production and the destination markets are different. Overall, the extent of preferentiality and partner selection at the sector level confirm the relevance of international trade costs still today, inducing countries to seek the highest efficiency in their trade patterns. PMID:26485163

  20. Photonic devices based on preferential etching.

    PubMed

    Bellini, Bob; Larchanché, Jean-François; Vilcot, Jean-Pierre; Decoster, Didier; Beccherelli, Romeo; d'Alessandro, Antonio

    2005-11-20

    We introduce a design concept of optical waveguides characterized by a practical and reproducible process based on preferential etching of crystalline silicon substrates. Low-loss waveguides, spot-size converters, and power dividers have been obtained with polymers. We have also aligned liquid crystals in the waveguides and demonstrated guided propagation. Therefore this technology is a suitable platform for soft-matter photonics and heterogeneous integration. PMID:16318190

  1. Fusion of Pedigreed Preferential Relations as Beliefs

    NASA Astrophysics Data System (ADS)

    Suzuki, Yoshitaka; Tojo, Satoshi

    Belief fusion, instead of AGM belief revision, was first proposed to solve the problem of inconsistency, that arised from repetitive application of the operation when agents' knowledge were amalgamated. In the preceding work of Maynard-Reid II and Shoham, the fusion operator is applied to belief states, which is total preorders over possible worlds which is based on the semantics of belief revision. Moreover, they introduced the pedigreed belief state, which represented multiple sources of belief states, ordered by a credibility ranking. However in the theory, all the sources must be totally ordered and thus applicable area is quite restrictive. In this paper, we realize the fusion operator of multiple agents for partially ordered sources. When we consider such a partial ranking over sources, there is no need to restrict that each agent has total preorders over possible worlds. The preferential model, based on the semantics on nonmonotonic reasoning, allows each agent to have strict partial orders over possible worlds. Especially, such an order is called a preferential relation, that prescribes a world is more plausible than the other. Therefore, we introduce an operation which combines multiple preferential relations of agents. In addition, we show that our operation can properly include the ordinary belief fusion.

  2. Spatial and temporal occurrence of preferential flow in a forested headwater catchment

    NASA Astrophysics Data System (ADS)

    Wiekenkamp, I.; Huisman, J. A.; Bogena, H. R.; Lin, H. S.; Vereecken, H.

    2016-03-01

    The highly dynamic nature of preferential flow in time and space makes it challenging to identify and analyze its occurrence at the catchment scale. Novel analysis methods using soil moisture sensor response times offer an opportunity to investigate catchment-wide controls on preferential flow. The aim of this study was to identify factors that control preferential flow occurrence based on 3-year soil moisture monitoring using a wireless sensor network in the Wüstebach catchment, Germany. At 101 locations, the sensor response times at three depths (5, 20, and 50 cm) were classified into one of four classes: (1) non-sequential preferential flow, (2) velocity-based preferential flow, (3) sequential flow, and (4) no response. A conceptual model, postulating that preferential flow in the Wüstebach catchment is dominated by differences in soil type, landscape position, and rainfall input, was proposed for hypothesis testing. To test the conceptual model, the classification results were combined with spatial and event-based data to understand and identify controlling factors. Spatial parameters consisted of hydrological, topographical, and soil physical and chemical parameters. Temporal factors included precipitation characteristics and antecedent soil moisture conditions. The conceptual model as proposed could only be partly confirmed. Event-based occurrence of preferential flow was highly affected by precipitation amount, with a nearly catchment-wide preferential response during large storm events. During intermediate events, preferential flow was controlled by small-scale heterogeneity, instead of showing catchment-wide patterns. The effect of antecedent catchment wetness on the occurrence of preferential flow was generally less profound, although a clear negative relationship was found for precipitation events with more than 25 mm. It was found that spatial occurrence of preferential flow was however governed by small-scale soil and biological features and local

  3. Micromechanical die attachment surcharge

    DOEpatents

    Filter, William F.; Hohimer, John P.

    2002-01-01

    An attachment structure is disclosed for attaching a die to a supporting substrate without the use of adhesives or solder. The attachment structure, which can be formed by micromachining, functions purely mechanically in utilizing a plurality of shaped pillars (e.g. round, square or polygonal and solid, hollow or slotted) that are formed on one of the die or supporting substrate and which can be urged into contact with various types of mating structures including other pillars, a deformable layer or a plurality of receptacles that are formed on the other of the die or supporting substrate, thereby forming a friction bond that holds the die to the supporting substrate. The attachment structure can further include an alignment structure for precise positioning of the die and supporting substrate to facilitate mounting the die to the supporting substrate. The attachment structure has applications for mounting semiconductor die containing a microelectromechanical (MEM) device, a microsensor or an integrated circuit (IC), and can be used to form a multichip module. The attachment structure is particularly useful for mounting die containing released MEM devices since these devices are fragile and can otherwise be damaged or degraded by adhesive or solder mounting.

  4. Attachment and early maltreatment.

    PubMed

    Egeland, B; Sroufe, L A

    1981-03-01

    Attachment outcomes of 31 maltreatment cases (extreme neglect or abuse) selected from a total poverty sample of 267 high-risk mothers were compared at 12 and 18 months to a subsample of 33 cases with a history of excellent care. In accordance with the Bowlby-Ainsworth hypothesis, the maltreatment group was characterized by a low proportion of secure attachment (Ainsworth's group B) at 12 months (38% compared to 75% in the excellent care group and 55% in the remaining total sample); however, differences at 18 months were not significant. Specifically, 50% of the cases with a history of neglect were in Ainsworth's group C (anxious/resistant attachment) at 12 months, compared to usual reports of approximately 10% and compared to 21% in the total poverty sample. Patterns of attachment between 12 and 18 months remained stable for the mother-infant pairs in the excellent care group, however, 52% of the mistreated infants changed classifications. For the neglect subgroup there was considerable movement toward Ainsworth's group A (anxious/avoidant attachment) at 18 months and some movement toward group B. An examination of the case histories of mother-infant pairs indicated that changes in attachment between 12 and 18 months were related to changing life events, support from family, and out-of-home care. These findings are highly tentative as were the findings which suggested that secure attachment within the maltreatment group was associated with the presence of a supportive family member, less chaotic life-style, and, in some instances, a more robust infant. PMID:7238152

  5. A case study of preferential bestiality (zoophilia).

    PubMed

    Earls, Christopher M; Lalumière, Martin L

    2002-01-01

    Humans show a wide array of sexual preferences and behaviors. Although most humans prefer and have sex with consenting adults of the opposite sex, some individuals have unconventional preferences with regard to the sex or age of sexual partners, or with regard to the nature of sexual activities. In this paper, we describe a rare case of preferential bestiality, or zoophilia. The client meets the most stringent criteria for the diagnosis of zoophilia. In particular, his phallometrically measured arousal pattern shows a sexual preference for horses over other species, including humans. PMID:11803597

  6. Emergence of social structures via preferential selection

    NASA Astrophysics Data System (ADS)

    Lipowski, Adam; Lipowska, Dorota; Ferreira, Antonio Luis

    2014-09-01

    We examine a weighted-network multiagent model with preferential selection such that agents choose partners with probability p (w), where w is the number of their past selections. When p (w) increases sublinearly with the number of past selections [p(w)˜wα,α<1], agents develop a uniform preference for all other agents. At α =1, this state loses stability and more complex structures form. For a superlinear increase (α>1), strong heterogeneities emerge and agents make selections mainly within small and sometimes asymmetric clusters. Even in a few-agent case, the formation of such clusters resembles phase transitions with spontaneous symmetry breaking.

  7. Autism and Attachment: The Attachment Q-Sort

    ERIC Educational Resources Information Center

    Rutgers, Anna H.; Van Ijzendoorn, Marinus H.; Bakermans-Kranenburg, Marian J.; Swinkels, Sophie H. N.

    2007-01-01

    Children with autism are able to show secure attachment behaviours to their parents/caregivers. Most studies on attachment in children with autism used a (modified) Strange Situation Procedure (SSP) to examine attachment security. An advantage of the Attachment Q-Sort (AQS) over the SSP is that it can be attuned to the secure-base behaviour of…

  8. Superego: an attachment perspective.

    PubMed

    Holmes, Jeremy

    2011-10-01

    With the help of attachment theory and research, the paper attempts to broaden and build on classical and current views on the superego. Attachment theory's epigenetic approach and the concept of the subliminal superego are described. The superego, it is argued, is as much concerned with safety as sex. The superego is 'heir', not just to the Oedipus complex or Klein's pre-oedipal constellation, but also to the attachment relationship. Under favourable developmental conditions a 'mature superego' emerges, facilitating, in the presence of an internal secure base, maturational boundary crossings towards adult sexuality. In the light of the above, the paper reviews Lear's updating of Strachey's model of psychic change and explores the concept of transgression in relation to the 'professional superego', its development and maturation. Theoretical arguments are illustrated with clinical examples. PMID:22014367

  9. Ceramic blade attachment system

    DOEpatents

    Boyd, Gary L.

    1994-01-01

    A turbine blade having a preestablished rate of thermal expansion is attached to a turbine wheel having a preestablished rate of thermal expansion being greater than the preestablished rate of thermal expansion of the turbine blade. The turbine blade has a root portion having a pair of recessed portions thereon. The turbine wheel includes a plurality of openings in which the turbine blade is positioned. Each of the openings have a pair of grooves therein in which are positioned a pair of pins having a generally rectangular cross-section and a reaction surface thereon. A pair of cylindrical rollers interposed respective ones of the pair of reaction surfaces and the pair of recessed portions. The attachment system or turbine assembly provides an economical, reliable and effective attachment of a component having a preestablished rate of thermal expansion to a component having a greater preestablished rate of thermal expansion.

  10. Ceramic blade attachment system

    DOEpatents

    Boyd, G.L.

    1994-12-13

    A turbine blade having a preestablished rate of thermal expansion is attached to a turbine wheel having a preestablished rate of thermal expansion being greater than the preestablished rate of thermal expansion of the turbine blade. The turbine blade has a root portion having a pair of recessed portions thereon. The turbine wheel includes a plurality of openings in which the turbine blade is positioned. Each of the openings have a pair of grooves therein in which are positioned a pair of pins having a generally rectangular cross-section and a reaction surface thereon. A pair of cylindrical rollers interposed respective ones of the pair of reaction surfaces and the pair of recessed portions. The attachment system or turbine assembly provides an economical, reliable and effective attachment of a component having a preestablished rate of thermal expansion to a component having a greater preestablished rate of thermal expansion. 3 figures.

  11. Preferential Flow in Fractured Welded Tuffs

    SciTech Connect

    Salve, Rohit

    2004-08-15

    To better understand preferential flow in fractured rock, we carried out an in situ field experiment in the Exploratory Studies Facility at Yucca Mountain, Nevada. This experiment involved the release of {approx} 22 m3 of ponded water (at a pressure head of {approx} 0.04 m) over a period of 7 months, directly onto a 12 m2 infiltration plot located on a fractured welded tuff surface. As water was released, changes in moisture content were monitored along horizontal boreholes located in the formation {approx} 19-22 m below. Distinct flow zones, varying in flow velocity, wetted cross-sectional area, and extent of lateral movement, intercepted the monitoring boreholes. There was also evidence of water being diverted above the ceiling of a cavity in the immediate vicinity of the monitoring boreholes. Observations from this field experiment suggest that isolated conduits, each encompassing a large number of fractures, develop within the fractured rock formation to form preferential flow paths that persist if there is a continuous supply of water. In addition, in fractured welded tuffs the propensity for fracture-matrix interactions is significantly greater than that suggested by existing conceptual models,in which flow occurs along a section of fracture surfaces. An overriding conclusion is that field investigations at spatial scales of tens of meters provide data critical to the fundamental understanding of flow in fractured rock.

  12. Internal pipe attachment mechanism

    DOEpatents

    Bast, Richard M.; Chesnut, Dwayne A.; Henning, Carl D.; Lennon, Joseph P.; Pastrnak, John W.; Smith, Joseph A.

    1994-01-01

    An attachment mechanism for repairing or extending fluid carrying pipes, casings, conduits, etc. utilizing one-way motion of spring tempered fingers to provide a mechanical connection between the attachment mechanism and the pipe. The spring tempered fingers flex to permit insertion into a pipe to a desired insertion depth. The mechanical connection is accomplished by reversing the insertion motion and the mechanical leverage in the fingers forces them outwardly against the inner wall of the pipe. A seal is generated by crushing a sealing assembly by the action of setting the mechanical connection.

  13. Internal pipe attachment mechanism

    DOEpatents

    Bast, R.M.; Chesnut, D.A.; Henning, C.D.; Lennon, J.P.; Pastrnak, J.W.; Smith, J.A.

    1994-12-13

    An attachment mechanism is described for repairing or extending fluid carrying pipes, casings, conduits, etc. utilizing one-way motion of spring tempered fingers to provide a mechanical connection between the attachment mechanism and the pipe. The spring tempered fingers flex to permit insertion into a pipe to a desired insertion depth. The mechanical connection is accomplished by reversing the insertion motion and the mechanical leverage in the fingers forces them outwardly against the inner wall of the pipe. A seal is generated by crushing a sealing assembly by the action of setting the mechanical connection. 6 figures.

  14. Magnetically attached sputter targets

    DOEpatents

    Makowiecki, D.M.; McKernan, M.A.

    1994-02-15

    An improved method and assembly for attaching sputtering targets to cathode assemblies of sputtering systems which includes a magnetically permeable material is described. The magnetically permeable material is imbedded in a target base that is brazed, welded, or soldered to the sputter target, or is mechanically retained in the target material. Target attachment to the cathode is achieved by virtue of the permanent magnets and/or the pole pieces in the cathode assembly that create magnetic flux lines adjacent to the backing plate, which strongly attract the magnetically permeable material in the target assembly. 11 figures.

  15. Magnetically attached sputter targets

    DOEpatents

    Makowiecki, Daniel M.; McKernan, Mark A.

    1994-01-01

    An improved method and assembly for attaching sputtering targets to cathode assemblies of sputtering systems which includes a magnetically permeable material. The magnetically permeable material is imbedded in a target base that is brazed, welded, or soldered to the sputter target, or is mechanically retained in the target material. Target attachment to the cathode is achieved by virtue of the permanent magnets and/or the pole pieces in the cathode assembly that create magnetic flux lines adjacent to the backing plate, which strongly attract the magnetically permeable material in the target assembly.

  16. Ladder attachment platform

    DOEpatents

    Swygert,; Richard, W [Springfield, SC

    2012-08-28

    A ladder attachment platform is provided that includes a base for attachment to a ladder that has first and second side rails and a plurality of rungs that extend between in a lateral direction. Also included is a user platform for having a user stand thereon that is carried by the base. The user platform may be positioned with respect to the ladder so that it is not located between a first plane that extends through the first side rail and is perpendicular to the lateral direction and a second plane that extends through the second side rail and is perpendicular to the lateral direction.

  17. Effect of elevated CO2 on the dynamics of particle-attached and free-living bacterioplankton communities in an Arctic fjord

    NASA Astrophysics Data System (ADS)

    Sperling, M.; Piontek, J.; Gerdts, G.; Wichels, A.; Schunck, H.; Roy, A.-S.; La Roche, J.; Gilbert, J.; Nissimov, J. I.; Bittner, L.; Romac, S.; Riebesell, U.; Engel, A.

    2013-01-01

    In the frame of the European Project on Ocean Acidification (EPOCA), the response of an Arctic pelagic community (<3 mm) to a gradient of seawater pCO2 was investigated. For this purpose 9 large-scale in situ mesocosms were deployed in Kongsfjorden, Svalbard (78°56.2´ N, 11°53.6´ E), in 2010. The present study investigates effects on the communities of particle-attached (PA; >3 μm) and free-living (FL; < 3 μm > 0.2 μm) bacteria by Automated Ribosomal Intergenic Spacer Analysis (ARISA) in 6 of the mesocosms, ranging from 185 to 1050 μatm initial pCO2, and the surrounding fjord. ARISA was able to resolve, on average, 27 bacterial band classes per sample and allowed for a detailed investigation of the explicit richness and diversity. Both, the PA and the FL bacterioplankton community exhibited a strong temporal development, which was driven mainly by temperature and phytoplankton development. In response to the breakdown of a picophytoplankton bloom, numbers of ARISA band classes in the PA community were reduced at low and medium CO2 (~ 185-685 μatm) by about 25%, while they were more or less stable at high CO2 (~ 820-1050 μatm). We hypothesise that enhanced viral lysis and enhanced availability of organic substrates at high CO2 resulted in a more diverse PA bacterial community in the post-bloom phase. Despite lower cell numbers and extracellular enzyme activities in the post-bloom phase, bacterial protein production was enhanced in high CO2 mesocosms, suggesting a positive effect of community richness on this function and on carbon cycling by bacteria.

  18. Stochastic Dynamical Model of a Growing Citation Network Based on a Self-Exciting Point Process

    NASA Astrophysics Data System (ADS)

    Golosovsky, Michael; Solomon, Sorin

    2012-08-01

    We put under experimental scrutiny the preferential attachment model that is commonly accepted as a generating mechanism of the scale-free complex networks. To this end we chose a citation network of physics papers and traced the citation history of 40 195 papers published in one year. Contrary to common belief, we find that the citation dynamics of the individual papers follows the superlinear preferential attachment, with the exponent α=1.25-1.3. Moreover, we show that the citation process cannot be described as a memoryless Markov chain since there is a substantial correlation between the present and recent citation rates of a paper. Based on our findings we construct a stochastic growth model of the citation network, perform numerical simulations based on this model and achieve an excellent agreement with the measured citation distributions.

  19. Attachment and Personality Disorders

    ERIC Educational Resources Information Center

    Sinha, Preeti; Sharan, Pratap

    2007-01-01

    Personality disorders (PDs) arise from core psychopathology of interpersonal relationships and understanding of self and others. The distorted representations of self and others, as well as unhealthy relationships that characterize persons with various PDs, indicate the possibility that persons with PDs have insecure attachment. Insecure…

  20. A case study of preferential bestiality.

    PubMed

    Earls, Christopher M; Lalumière, Martin L

    2009-08-01

    In a previous article, we presented phallometric data to illustrate a case of preferential bestiality or zoophilia (Earls & Lalumière, Sex Abuse: J Res Treat, 14:83-88, 2002). Based on the available literature, we argued that a marked preference for having sex with animals over sex with humans is extremely rare. In the present article, we describe a second case of zoophilia that challenges the widely held assumptions that men who have sex with animals are generally of below average intelligence and come from rural areas. In addition, we provide a brief review of a burgeoning quantitative literature using large groups of zoophiles recruited from internet sources. Although estimates of the prevalence of zoophilia are not possible at this time, it appears that zoophilia is not as rare as once thought and shares many features with other atypical sexual interests. PMID:18157625

  1. Crystal Orientation Dynamics of Collective Zn dots before Preferential Nucleation

    PubMed Central

    Liu, Chun-Chu; Huang, Jun-Han; Ku, Ching-Shun; Chiu, Shang-Jui; Ghatak, Jay; Brahma, Sanjaya; Liu, Chung-Wei; Liu, Chuan-Pu; Lo, Kuang-Yao

    2015-01-01

    The island nucleation in the context of heterogeneous thin film growth is often complicated by the growth kinetics involved in the subsequent thermodynamics. We show how the evolution of sputtered Zn island nucleation on Si(111) by magnetron sputtering in a large area can be completely understood as a model system by combining reflective second harmonic generation (RSHG), a 2D pole figure with synchrotron X-ray diffraction. Zn dots are then oxidized on the surfaces when exposed to the atmosphere as Zn/ZnO dots. Derived from the RSHG patterns of Zn dots at different growth times, the Zn dots grow following a unique transition from kinetic to thermodynamic control. Under kinetic-favoring growth, tiny Zn dots prefer arranging themselves with a tilted c-axis to the Si(111) substrate toward any of the sixfold in-plane Si<110> directions. Upon growth, the Zn dots subsequently evolve themselves to a metastable state with a smaller tilting angle toward selective <110> directions. As the Zn dots grow over a critical size, they become most thermodynamically stable with the c-axis vertical to the Si(111) substrate. For a system with large lattice mismatch, small volume dots take kinetic pathways with insignificant deviations in energy barriers. PMID:26211998

  2. Crystal Orientation Dynamics of Collective Zn dots before Preferential Nucleation

    NASA Astrophysics Data System (ADS)

    Liu, Chun-Chu; Huang, Jun-Han; Ku, Ching-Shun; Chiu, Shang-Jui; Ghatak, Jay; Brahma, Sanjaya; Liu, Chung-Wei; Liu, Chuan-Pu; Lo, Kuang-Yao

    2015-07-01

    The island nucleation in the context of heterogeneous thin film growth is often complicated by the growth kinetics involved in the subsequent thermodynamics. We show how the evolution of sputtered Zn island nucleation on Si(111) by magnetron sputtering in a large area can be completely understood as a model system by combining reflective second harmonic generation (RSHG), a 2D pole figure with synchrotron X-ray diffraction. Zn dots are then oxidized on the surfaces when exposed to the atmosphere as Zn/ZnO dots. Derived from the RSHG patterns of Zn dots at different growth times, the Zn dots grow following a unique transition from kinetic to thermodynamic control. Under kinetic-favoring growth, tiny Zn dots prefer arranging themselves with a tilted c-axis to the Si(111) substrate toward any of the sixfold in-plane Si<110> directions. Upon growth, the Zn dots subsequently evolve themselves to a metastable state with a smaller tilting angle toward selective <110> directions. As the Zn dots grow over a critical size, they become most thermodynamically stable with the c-axis vertical to the Si(111) substrate. For a system with large lattice mismatch, small volume dots take kinetic pathways with insignificant deviations in energy barriers.

  3. Turbine nozzle attachment system

    DOEpatents

    Norton, Paul F.; Shaffer, James E.

    1995-01-01

    A nozzle guide vane assembly having a preestablished rate of thermal expansion is positioned in a gas turbine engine and being attached to conventional metallic components. The nozzle guide vane assembly includes a pair of legs extending radially outwardly from an outer shroud and a pair of mounting legs extending radially inwardly from an inner shroud. Each of the pair of legs and mounting legs have a pair of holes therein. A plurality of members attached to the gas turbine engine have a plurality of bores therein which axially align with corresponding ones of the pair of holes in the legs. A plurality of pins are positioned within the corresponding holes and bores radially positioning the nozzle guide vane assembly about a central axis of the gas turbine engine.

  4. Turbine nozzle attachment system

    DOEpatents

    Norton, P.F.; Shaffer, J.E.

    1995-10-24

    A nozzle guide vane assembly having a preestablished rate of thermal expansion is positioned in a gas turbine engine and is attached to conventional metallic components. The nozzle guide vane assembly includes a pair of legs extending radially outwardly from an outer shroud and a pair of mounting legs extending radially inwardly from an inner shroud. Each of the pair of legs and mounting legs have a pair of holes therein. A plurality of members attached to the gas turbine engine have a plurality of bores therein which axially align with corresponding ones of the pair of holes in the legs. A plurality of pins are positioned within the corresponding holes and bores radially positioning the nozzle guide vane assembly about a central axis of the gas turbine engine. 3 figs.

  5. WP-2 attached payload accommodations

    NASA Technical Reports Server (NTRS)

    Scheib, Jim

    1992-01-01

    The presentation provides an overview of the current SSFP attached payload accommodations on the U.S. truss. The overview includes discussions on the four attach sites, the power architecture, thermal control, DMS provisions, and the mechanical attach mechanism. The presentation concludes with a description of a McDonnell Douglas concept for an attached payload pallet designed to take advantage of the four sites and existing SSF hardware. This presentation should provide the payload community with a basic understanding of the SSF attached payload utility ports and aid in attached payload concept development.

  6. Leadership and attachment theory.

    PubMed

    Bresnahan, Christopher G; Mitroff, Ian I

    2007-09-01

    Comments on the six articles contained in the special issue of the American Psychologist (January 2007) devoted to leadership, written by W. Bennis; S. J. Zaccaro; V. H. Vroom and A. G. Yago; B. J. Avolio; R. J. Sternberg; and R. J. Hackman and R. Wageman. The current authors opine that the inclusion of attachment theory in the study of leadership could strengthen leadership theories as a whole. PMID:17874909

  7. Chemically-specific time-resolved surface photovoltage spectroscopy: Carrier dynamics at the interface of quantum dots attached to a metal oxide

    NASA Astrophysics Data System (ADS)

    Spencer, Ben F.; Cliffe, Matthew J.; Graham, Darren M.; Hardman, Samantha J. O.; Seddon, Elaine A.; Syres, Karen L.; Thomas, Andrew G.; Sirotti, Fausto; Silly, Mathieu G.; Akhtar, Javeed; O'Brien, Paul; Fairclough, Simon M.; Smith, Jason M.; Chattopadhyay, Swapan; Flavell, Wendy R.

    2015-11-01

    We describe a new experimental pump-probe methodology where a 2D delay-line detector enables fast (ns) monitoring of a narrow XPS spectrum in combination with a continuous pump laser. This has been developed at the TEMPO beamline at Synchrotron SOLEIL to enable the study of systems with intrinsically slow electron dynamics, and to complement faster measurements that use a fs laser as the pump. We demonstrate its use in a time-resolved study of the surface photovoltage of the m-plane ZnO (10 1 bar 0) surface which shows persistent photoconductivity, requiring monitoring periods on ms timescales and longer. We make measurements from this surface in the presence and absence of chemically-linked quantum dots (QDs), using type I PbS and type II CdSe/ZnSe (core/shell) QDs as examples. We monitor signals from both the ZnO substrate and the bound QDs during photoexcitation, yielding evidence for charge injection from the QDs into the ZnO. The chemical specificity of the technique allows us to observe differences in the extent to which the QD systems are influenced by the field of the surface depletion layer at the ZnO surface, which we attribute to differences in the band structure at the interface.

  8. Attachment as an Organizational Construct

    ERIC Educational Resources Information Center

    Sroufe, L. Alan; Waters, Everett

    1977-01-01

    Discusses the conflict between situational influences and stable individual differences in attachment behavior and attempts to resolve this conflict by examining the functions, outcomes, and context sensitivity of attachment behavior and the underlying behavioral control systems that organize it. (JMB)

  9. Preferential solvation: dividing surface vs excess numbers.

    PubMed

    Shimizu, Seishi; Matubayasi, Nobuyuki

    2014-04-10

    How do osmolytes affect the conformation and configuration of supramolecular assembly, such as ion channel opening and actin polymerization? The key to the answer lies in the excess solvation numbers of water and osmolyte molecules; these numbers are determinable solely from experimental data, as guaranteed by the phase rule, as we show through the exact solution theory of Kirkwood and Buff (KB). The osmotic stress technique (OST), in contrast, purposes to yield alternative hydration numbers through the use of the dividing surface borrowed from the adsorption theory. However, we show (i) OST is equivalent, when it becomes exact, to the crowding effect in which the osmolyte exclusion dominates over hydration; (ii) crowding is not the universal driving force of the osmolyte effect (e.g., actin polymerization); (iii) the dividing surface for solvation is useful only for crowding, unlike in the adsorption theory which necessitates its use due to the phase rule. KB thus clarifies the true meaning and limitations of the older perspectives on preferential solvation (such as solvent binding models, crowding, and OST), and enables excess number determination without any further assumptions. PMID:24689966

  10. Microfluidic study of bacterial interactions and attachment to oil drops

    NASA Astrophysics Data System (ADS)

    Juarez, Gabriel; Stocker, Roman

    2013-11-01

    The swimming dynamics of bacteria are strongly influenced by interfaces. Motile bacteria often accumulate near solid-liquid and liquid-liquid interfaces and eventually attach. Attachment of bacteria to these interfaces is crucial for the formation of biofilms (liquid-solid), pellicles (liquid-air), and oil-degrading communities (liquid-liquid). However, the mechanisms of attachment by microbes to these surfaces are not well understood. We have investigated the effect of external flow on the probability of attachment of motile and non-motile marine bacteria to oil droplets in straight microchannels. We find that motility enhances the encounter rate between bacteria and drops leading to an increase in attachment. Characterizing these interactions in the presence of flow will promote an understanding of oil-microbe and particulate-microbe interactions in aquatic environments where the degradation rate of organic matter depends on the attachment and colonization by bacteria.

  11. Scaling and biomechanics of surface attachment in climbing animals.

    PubMed

    Labonte, David; Federle, Walter

    2015-02-01

    Attachment devices are essential adaptations for climbing animals and valuable models for synthetic adhesives. A major unresolved question for both natural and bioinspired attachment systems is how attachment performance depends on size. Here, we discuss how contact geometry and mode of detachment influence the scaling of attachment forces for claws and adhesive pads, and how allometric data on biological systems can yield insights into their mechanism of attachment. Larger animals are expected to attach less well to surfaces, due to their smaller surface-to-volume ratio, and because it becomes increasingly difficult to distribute load uniformly across large contact areas. In order to compensate for this decrease of weight-specific adhesion, large animals could evolve overproportionally large pads, or adaptations that increase attachment efficiency (adhesion or friction per unit contact area). Available data suggest that attachment pad area scales close to isometry within clades, but pad efficiency in some animals increases with size so that attachment performance is approximately size-independent. The mechanisms underlying this biologically important variation in pad efficiency are still unclear. We suggest that switching between stress concentration (easy detachment) and uniform load distribution (strong attachment) via shear forces is one of the key mechanisms enabling the dynamic control of adhesion during locomotion. PMID:25533088

  12. Scaling and biomechanics of surface attachment in climbing animals

    PubMed Central

    Labonte, David; Federle, Walter

    2015-01-01

    Attachment devices are essential adaptations for climbing animals and valuable models for synthetic adhesives. A major unresolved question for both natural and bioinspired attachment systems is how attachment performance depends on size. Here, we discuss how contact geometry and mode of detachment influence the scaling of attachment forces for claws and adhesive pads, and how allometric data on biological systems can yield insights into their mechanism of attachment. Larger animals are expected to attach less well to surfaces, due to their smaller surface-to-volume ratio, and because it becomes increasingly difficult to distribute load uniformly across large contact areas. In order to compensate for this decrease of weight-specific adhesion, large animals could evolve overproportionally large pads, or adaptations that increase attachment efficiency (adhesion or friction per unit contact area). Available data suggest that attachment pad area scales close to isometry within clades, but pad efficiency in some animals increases with size so that attachment performance is approximately size-independent. The mechanisms underlying this biologically important variation in pad efficiency are still unclear. We suggest that switching between stress concentration (easy detachment) and uniform load distribution (strong attachment) via shear forces is one of the key mechanisms enabling the dynamic control of adhesion during locomotion. PMID:25533088

  13. Attachment Behaviors in Autistic Children.

    ERIC Educational Resources Information Center

    Sigman, Marian; Ungerer, Judy A.

    1984-01-01

    Observation of 14 autistic and 14 nonautistic children of equivalent mental age revealed that autistic Ss showed evidence of attachment to their mothers. Among autistic Ss, those showing increased attachment behaviors in response to separation and reunion demonstrated more advanced symbolic play skills than those showing no attachment change.…

  14. Fractional Dynamics of Network Growth Constrained by Aging Node Interactions.

    PubMed

    Safdari, Hadiseh; Zare Kamali, Milad; Shirazi, Amirhossein; Khalighi, Moein; Jafari, Gholamreza; Ausloos, Marcel

    2016-01-01

    In many social complex systems, in which agents are linked by non-linear interactions, the history of events strongly influences the whole network dynamics. However, a class of "commonly accepted beliefs" seems rarely studied. In this paper, we examine how the growth process of a (social) network is influenced by past circumstances. In order to tackle this cause, we simply modify the well known preferential attachment mechanism by imposing a time dependent kernel function in the network evolution equation. This approach leads to a fractional order Barabási-Albert (BA) differential equation, generalizing the BA model. Our results show that, with passing time, an aging process is observed for the network dynamics. The aging process leads to a decay for the node degree values, thereby creating an opposing process to the preferential attachment mechanism. On one hand, based on the preferential attachment mechanism, nodes with a high degree are more likely to absorb links; but, on the other hand, a node's age has a reduced chance for new connections. This competitive scenario allows an increased chance for younger members to become a hub. Simulations of such a network growth with aging constraint confirm the results found from solving the fractional BA equation. We also report, as an exemplary application, an investigation of the collaboration network between Hollywood movie actors. It is undubiously shown that a decay in the dynamics of their collaboration rate is found, even including a sex difference. Such findings suggest a widely universal application of the so generalized BA model. PMID:27171424

  15. Fractional Dynamics of Network Growth Constrained by Aging Node Interactions

    PubMed Central

    Safdari, Hadiseh; Zare Kamali, Milad; Shirazi, Amirhossein; Khalighi, Moein; Jafari, Gholamreza; Ausloos, Marcel

    2016-01-01

    In many social complex systems, in which agents are linked by non-linear interactions, the history of events strongly influences the whole network dynamics. However, a class of “commonly accepted beliefs” seems rarely studied. In this paper, we examine how the growth process of a (social) network is influenced by past circumstances. In order to tackle this cause, we simply modify the well known preferential attachment mechanism by imposing a time dependent kernel function in the network evolution equation. This approach leads to a fractional order Barabási-Albert (BA) differential equation, generalizing the BA model. Our results show that, with passing time, an aging process is observed for the network dynamics. The aging process leads to a decay for the node degree values, thereby creating an opposing process to the preferential attachment mechanism. On one hand, based on the preferential attachment mechanism, nodes with a high degree are more likely to absorb links; but, on the other hand, a node’s age has a reduced chance for new connections. This competitive scenario allows an increased chance for younger members to become a hub. Simulations of such a network growth with aging constraint confirm the results found from solving the fractional BA equation. We also report, as an exemplary application, an investigation of the collaboration network between Hollywood movie actors. It is undubiously shown that a decay in the dynamics of their collaboration rate is found, even including a sex difference. Such findings suggest a widely universal application of the so generalized BA model. PMID:27171424

  16. Assessment of attachment behaviour to human caregivers in wolf pups (Canis lupus lupus).

    PubMed

    Hall, Nathaniel J; Lord, Kathryn; Arnold, Anne-Marie K; Wynne, Clive D L; Udell, Monique A R

    2015-01-01

    Previous research suggested that 16-week old dog pups, but not wolf pups, show attachment behaviour to a human caregiver. Attachment to a caregiver in dog pups has been demonstrated by differential responding to a caregiver compared to a stranger in the Ainsworth Strange Situation Test. We show here that 3-7 week old wolf pups also show attachment-like behaviour to a human caregiver as measured by preferential proximity seeking, preferential contact, and preferential greeting to a human caregiver over a human stranger in a modified and counterbalanced version of the Ainsworth Strange Situation Test. In addition, our results show that preferential responding to a caregiver over a stranger is only apparent following brief isolation. In initial episodes, wolf pups show no differentiation between the caregiver and the stranger; however, following a 2-min separation, the pups show proximity seeking, more contact, and more greeting to the caregiver than the stranger. These results suggest intensive human socialization of a wolf can lead to attachment--like responding to a human caregiver during the first two months of a wolf pup's life. PMID:25447510

  17. Quantifying attachment and antibiotic resistance of Escherichia coli from conventional and organic swine manure

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Broad spectrum antibiotics, used to treat infections in livestock, are often administered at sub-therapeutic levels in feed rations to promote growth and for prophylaxis. Previous studies have shown that bacteria preferentially attach to sediments affecting their transport in overland flow; however...

  18. Magnetic attachment mechanism

    NASA Technical Reports Server (NTRS)

    Harwell, William D. (Inventor); Wu, Mitchell B. (Inventor)

    1990-01-01

    A magnetic attachment mechanism adapted for interfacing with the manipulator arm (11) of a remote manipulator system and comprising a pair of permanent magnets (31,32) of rare earth material which are arranged in a stator-rotor relationship. The rotor magnet (32), is journalled for rotation about its longitudinal axis between pole plates (35,36) of the stator magnet (31), each of which includes an adhering surface (35a,36a). In a first rotary position corresponding to the ON condition, each of the poles of the rotor magnet (32) is closely adjacent a stator magnet pole plate of like polarity whereby the respective magnet fields are additive for producing a strong magnetic field emanating from the adhering surfaces (35a,36a) for attracting a ferrous magnetic plate 20, or the like, affixed to the payload (20 or 50). When the rotor magnet (32) is rotated to a second position corresponding to the OFF condition, each of the poles of the rotor magnet (31) is disposed closely adjacent a pole plate of unlike polarity whereby the magnetic fields of the magnets are in cancelling relationship at the adhering surfaces (35a,36a) which permits the release of a payload. An actuator (51 or 70) for selectively rotating the rotor magnet (32) between the ON and OFF positions is provided for interfacing and connecting the magnetic attachment mechanism with a manipulator arm. For effecting an optimal rigidized attachment the payload is provided with guides (91,92) cooperable with guides (96,16,17) on the housing of the mechanism for directing adhering surfaces (35a,36a) of the polar plates to the ferrous plate (20).

  19. A coevolving model based on preferential triadic closure for social media networks

    PubMed Central

    Li, Menghui; Zou, Hailin; Guan, Shuguang; Gong, Xiaofeng; Li, Kun; Di, Zengru; Lai, Choy-Heng

    2013-01-01

    The dynamical origin of complex networks, i.e., the underlying principles governing network evolution, is a crucial issue in network study. In this paper, by carrying out analysis to the temporal data of Flickr and Epinions–two typical social media networks, we found that the dynamical pattern in neighborhood, especially the formation of triadic links, plays a dominant role in the evolution of networks. We thus proposed a coevolving dynamical model for such networks, in which the evolution is only driven by the local dynamics–the preferential triadic closure. Numerical experiments verified that the model can reproduce global properties which are qualitatively consistent with the empirical observations. PMID:23979061

  20. Flared tube attachment fitting

    NASA Technical Reports Server (NTRS)

    Alkire, I. D.; King, J. P., Jr.

    1980-01-01

    Tubes can be flared first, then attached to valves and other flow line components, with new fitting that can be disassembled and reused. Installed fitting can be disassembled so parts can be inspected. It can be salvaged and reused without damaging flared tube; tube can be coated, tempered, or otherwise treated after it has been flared, rather than before, as was previously required. Fitting consists of threaded male portion with conical seating surface, hexagonal nut with hole larger than other diameter of flared end of tube, and split ferrule.

  1. Effect of attachment strategies on bipartite networks

    NASA Astrophysics Data System (ADS)

    Ganguly, Niloy; Saha, Sudipta; Maiti, Abyayananda; Agarwal, Sanket; Peruani, Fernando; Mukherjee, Animesh

    2013-06-01

    Bipartite systems show remarkable variations in their topological asymptotic properties, e.g., in their degree distribution. Such variations depend on the underlying growth dynamics. A scenario of particular importance is when the two partitions of the bipartite structure do not grow at an equal rate. Here, we focus on the case where one of the partitions can be assumed to be fixed while the other partition grows in time as observed in the codon-gene or alphabet-word network. We show that subtle changes in growth dynamics, particularly in the attachment kernel, can lead to drastic changes of the emergent topological properties. We present a detail analysis of various growth strategies, including sequential and parallel addition of nodes, as well as with and without replacement attachment kernels. Analytical results have been compared with stochastic simulations as well as with real systems showing in all cases an excellent agreement.

  2. Ceramic blade attachment system

    DOEpatents

    Frey, G.A.; Jimenez, O.D.

    1996-12-03

    A turbine blade having a preestablished rate of thermal expansion is attached to a turbine flange having a preestablished rate of thermal expansion being greater than the preestablished rate of thermal expansion of the turbine blade. The turbine flange includes a first upstanding flange and a second upstanding flange having a groove formed between them. The turbine flange further includes a recess. Each of the first and second upstanding flanges have a plurality of bores therein. A turbine blade has a first member and a second member positioned in one of the groove and the recess. Each of the first member and the second member have a plurality of bores therein. A pin is positioned in respective ones of the plurality of bores in the first and second upstanding members and the first and second members and attach the blade to the turbine flange. The pin has a preestablished rate of thermal expansion being substantially equal to the rate of thermal expansion of the blade. 4 figs.

  3. Ceramic blade attachment system

    DOEpatents

    Frey, deceased, Gary A.; Jimenez, Oscar D.

    1996-01-01

    A turbine blade having a preestablished rate of thermal expansion is attached to a turbine flange having a preestablished rate of thermal expansion being greater than the preestablished rate of thermal expansion of the turbine blade. The turbine flange includes a first upstanding flange and a second upstanding flange having a groove formed therebetween. The turbine flange further includes a recess. Each of the first and second upstanding flanges have a plurality of bores therein. A turbine blade has a first member and a second member positioned in one of the groove and the recess. Each of the first member and the second member have a plurality of bores therein. And, a pin is positioned in respective ones of the plurality of bores in the first and second upstanding members and the first and second members and attach the blade to the turbine flange. The pin has a preestablished rate of thermal expansion being substantially equal to the rate of thermal expansion of the blade.

  4. Conflicting attachment and the growth of bipartite networks

    NASA Astrophysics Data System (ADS)

    Leung, Chung Yin Joey; Weitz, Joshua S.

    2016-03-01

    Simple growth mechanisms have been proposed to explain the emergence of seemingly universal network structures. The widely studied model of preferential attachment assumes that new nodes are more likely to connect to highly connected nodes. Preferential attachment explains the emergence of scale-free degree distributions within complex networks. Yet it is incompatible with many network systems, particularly bipartite systems in which two distinct types of agents interact. For example, the addition of new links in a host-parasite system corresponds to the infection of hosts by parasites. Increasing connectivity is beneficial to a parasite and detrimental to a host. Therefore, the overall network connectivity is subject to conflicting pressures. Here we propose a stochastic network growth model of conflicting attachment, inspired by a particular kind of parasite-host interaction: that of viruses interacting with microbial hosts. The mechanism of network growth includes conflicting preferences to network density as well as costs involved in modifying the network connectivity according to these preferences. We find that the resulting networks exhibit realistic patterns commonly observed in empirical data, including the emergence of nestedness, modularity, and nested-modular structures that exhibit both properties. We study the role of conflicting interests in shaping network structure and assess opportunities to incorporate greater realism in linking growth process to pattern in systems governed by antagonistic and mutualistic interactions.

  5. Preferential Option for the Poor: Making a Pedagogical Choice

    ERIC Educational Resources Information Center

    Kirylo, James D.

    2006-01-01

    When children are sick, hurt, or in desperate need, parents/caregivers naturally make preferential options for them. Yet, as it relates to social justice, particularly when working with students from marginalized and poverty situations, the concept of making a preferential option in a school setting is not as clear. However, a school setting is a…

  6. 19 CFR 10.213 - Articles eligible for preferential treatment.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 19 Customs Duties 1 2010-04-01 2010-04-01 false Articles eligible for preferential treatment. 10...; DEPARTMENT OF THE TREASURY ARTICLES CONDITIONALLY FREE, SUBJECT TO A REDUCED RATE, ETC. Textile and Apparel Articles Under the African Growth and Opportunity Act § 10.213 Articles eligible for preferential...

  7. 19 CFR 10.213 - Articles eligible for preferential treatment.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 19 Customs Duties 1 2011-04-01 2011-04-01 false Articles eligible for preferential treatment. 10...; DEPARTMENT OF THE TREASURY ARTICLES CONDITIONALLY FREE, SUBJECT TO A REDUCED RATE, ETC. Textile and Apparel Articles Under the African Growth and Opportunity Act § 10.213 Articles eligible for preferential...

  8. Modeling, Analysis and Simulation of Multiscale Preferential Flow - 8/05-8/10 - Final Report

    SciTech Connect

    Ralph Showalter; Malgorzata Peszynska

    2012-07-03

    The research agenda of this project are: (1) Modeling of preferential transport from mesoscale to macroscale; (2) Modeling of fast flow in narrow fractures in porous media; (3) Pseudo-parabolic Models of Dynamic Capillary Pressure; (4) Adaptive computational upscaling of flow with inertia from porescale to mesoscale; (5) Adaptive modeling of nonlinear coupled systems; and (6) Adaptive modeling and a-posteriori estimators for coupled systems with heterogeneous data.

  9. The Attachment and Clinical Issues Questionnaire (ACIQ): scale development.

    PubMed

    Lindberg, Marc A; Thomas, Stuart W

    2011-01-01

    In line with dynamic systems and dialectical theories of development, it was theorized that a psychopathology such as an addiction could have several causes (equifinality) and that more specific diagnoses and treatments of the most salient clinical issues for individuals coming from different developmental paths could increase the success rates of most therapies. Further, the issues from a developmental dynamic systems perspective should include not only individual clinical issues, but also relational, familial, peer, and organizational functioning. The Attachment and Clinical Issues Questionnaire (ACIQ) was developed as a research and clinical instrument relevant to these concerns. The 29 scales were based on naturalistic observations of patients in treatment and 12-step groups, attachment theory, and the clinical literature dealing with the addictions. The attachment scales were taken from classic attachment theory but, in line with more recent formulations, included relations to mother, father, and partner. Study 1 found the ACIQ to have good coefficient alphas (.79), and factor analyses revealed that the eight factors loaded on different attachment figures and sets of clinical issues rather than attachment styles per se. Study 2 found test-retest reliability to be, on average, .79. The results were in line with the developmental hypothesis that partner and father attachments are different than attachments to mother, and that family and peer relations as well as clinical issues need to be considered separately. PMID:22256681

  10. ATR inhibition preferentially targets homologous recombination-deficient tumor cells.

    PubMed

    Krajewska, M; Fehrmann, R S N; Schoonen, P M; Labib, S; de Vries, E G E; Franke, L; van Vugt, M A T M

    2015-06-01

    Homologous recombination (HR) is required for faithful repair of double-strand DNA breaks. Defects in HR repair cause severe genomic instability and challenge cellular viability. Paradoxically, various cancers are HR defective and have apparently acquired characteristics to survive genomic instability. We aimed to identify these characteristics to uncover therapeutic targets for HR-deficient cancers. Cytogenetic analysis of 1143 ovarian cancers showed that the degree of genomic instability was correlated to amplification of replication checkpoint genes ataxia telangiectasia and Rad3-related kinase (ATR) and CHEK1. To test whether genomic instability leads to increased reliance on replication checkpoint signaling, we inactivated Rad51 to model HR-related genomic instability. Rad51 inactivation caused defective HR repair and induced aberrant replication dynamics. Notably, inhibition of Rad51 led to increased ATR/checkpoint kinase-1 (Chk1)-mediated replication stress signaling. Importantly, inhibition of ATR or Chk1 preferentially killed HR-deficient cancer cells. Combined, our data show that defective HR caused by Rad51 inhibition results in differential sensitivity for ATR and Chk1 inhibitors, implicating replication checkpoint kinases as potential drug targets for HR-defective cancers. PMID:25174396

  11. Deciphering preferential interactions within supramolecular protein complexes: the proteasome case

    PubMed Central

    Fabre, Bertrand; Lambour, Thomas; Garrigues, Luc; Amalric, François; Vigneron, Nathalie; Menneteau, Thomas; Stella, Alexandre; Monsarrat, Bernard; Van den Eynde, Benoît; Burlet-Schiltz, Odile; Bousquet-Dubouch, Marie-Pierre

    2015-01-01

    In eukaryotic cells, intracellular protein breakdown is mainly performed by the ubiquitin–proteasome system. Proteasomes are supramolecular protein complexes formed by the association of multiple sub-complexes and interacting proteins. Therefore, they exhibit a very high heterogeneity whose function is still not well understood. Here, using a newly developed method based on the combination of affinity purification and protein correlation profiling associated with high-resolution mass spectrometry, we comprehensively characterized proteasome heterogeneity and identified previously unknown preferential associations within proteasome sub-complexes. In particular, we showed for the first time that the two main proteasome subtypes, standard proteasome and immunoproteasome, interact with a different subset of important regulators. This trend was observed in very diverse human cell types and was confirmed by changing the relative proportions of both 20S proteasome forms using interferon-γ. The new method developed here constitutes an innovative and powerful strategy that could be broadly applied for unraveling the dynamic and heterogeneous nature of other biologically relevant supramolecular protein complexes. PMID:25561571

  12. Functional hierarchy underlies preferential connectivity disturbances in schizophrenia.

    PubMed

    Yang, Genevieve J; Murray, John D; Wang, Xiao-Jing; Glahn, David C; Pearlson, Godfrey D; Repovs, Grega; Krystal, John H; Anticevic, Alan

    2016-01-12

    Schizophrenia may involve an elevated excitation/inhibition (E/I) ratio in cortical microcircuits. It remains unknown how this regulatory disturbance maps onto neuroimaging findings. To address this issue, we implemented E/I perturbations within a neural model of large-scale functional connectivity, which predicted hyperconnectivity following E/I elevation. To test predictions, we examined resting-state functional MRI in 161 schizophrenia patients and 164 healthy subjects. As predicted, patients exhibited elevated functional connectivity that correlated with symptom levels, and was most prominent in association cortices, such as the fronto-parietal control network. This pattern was absent in patients with bipolar disorder (n = 73). To account for the pattern observed in schizophrenia, we integrated neurobiologically plausible, hierarchical differences in association vs. sensory recurrent neuronal dynamics into our model. This in silico architecture revealed preferential vulnerability of association networks to E/I imbalance, which we verified empirically. Reported effects implicate widespread microcircuit E/I imbalance as a parsimonious mechanism for emergent inhomogeneous dysconnectivity in schizophrenia. PMID:26699491

  13. Preferentially Cytotoxic Constituents of Andrographis paniculata and their Preferential Cytotoxicity against Human Pancreatic Cancer Cell Lines.

    PubMed

    Lee, Sullim; Morita, Hiroyuki; Tezuka, Yasuhiro

    2015-07-01

    In the course of our search for anticancer agents based on a novel anti-austerity strategy, we found that the 70% EtOH extract of the crude drug Andrographis Herba (aerial parts of Andrographis paniculata), used in Japanese Kampo medicines, killed PANC-1 human pancreatic cancer cells preferentially in nutrient-deprived medium (NDM). Phytochemical investigation of the 70% EtOH extract led to the isolation of 21 known compounds consisting of six labdane-type diterpenes (11, 15, 17-19, 21), six flavones (5, 7, 10, 12, 14, 20), three flavanones (2, 6, 16), two sterols (3, 8), a fatty acid (1), a phthalate (4), a triterpene (9), and a monoterpene (13). Among them, 14-deoxy-11,12-didehydroandrographolide (17) displayed the most potent preferential cytotoxicity against PANC-1 and PSN-1 cells with PC50 values of 10.0 μM and 9.27 μM, respectively. Microscopical observation, double staining with ethidium bromide (EB) and acridine orange (AO), and flow cytometry with propidium iodide/annexin V double staining indicated that 14-deoxy-11,12-didehydroandrographolide (17) triggered apoptosis-like cell death in NDM with an amino acids and/or serum-sensitive mode. PMID:26410998

  14. Ceramic blade attachment system

    DOEpatents

    Shaffer, James E.

    1995-01-01

    A turbine blade having a preestablished rate of thermal expansion is attached to a turbine wheel having a preestablished rate of thermal expansion being greater than the preestablished rate of thermal expansion of the turbine blade. The turbine blade has a root portion having a first groove and a second groove therein. The turbine wheel includes a plurality of openings in which the turbine blade is positioned. Each of the openings has a first groove and a second groove therein. The space or void formed between the first grooves and the second grooves has a plurality of spherical balls positioned therein. The plurality of spherical balls has a preestablished rate of thermal expansion being equal to the preestablished rate of thermal expansion of the turbine blade.

  15. Ceramic blade attachment system

    DOEpatents

    Shaffer, James E.

    1995-01-01

    A turbine blade having a preestablished rate of thermal expansion is attached to a turbine disc having a preestablished rate of thermal expansion being greater than the preestablished rate of thermal expansion of the turbine blade and forms a turbine assembly. The turbine blade has a root portion defining a pair of sides having a pair of grooves therein. The turbine assembly includes a pair of flanges between which the turbine blades are positioned. Each of the pair of flanges has a plurality of grooves defined therein. The grooves within the pair of flanges are aligned with the grooves in the blades and have a space formed therebetween. A plurality of spherical balls are positioned within the space. The plurality of spherical balls has a preestablished rate of thermal expansion being equal to the preestablished rate of thermal expansion of the turbine blade.

  16. Ceramic blade attachment system

    DOEpatents

    Shaffer, J.E.

    1995-07-11

    A turbine blade having a preestablished rate of thermal expansion is attached to a turbine disc having a preestablished rate of thermal expansion being greater than the preestablished rate of thermal expansion of the turbine blade and forms a turbine assembly. The turbine blade has a root portion defining a pair of sides having a pair of grooves therein. The turbine assembly includes a pair of flanges between which the turbine blades are positioned. Each of the pair of flanges has a plurality of grooves defined therein. The grooves within the pair of flanges are aligned with the grooves in the blades and have a space formed therebetween. A plurality of spherical balls are positioned within the space. The plurality of spherical balls has a preestablished rate of thermal expansion being equal to the preestablished rate of thermal expansion of the turbine blade. 4 figs.

  17. Ceramic blade attachment system

    DOEpatents

    Shaffer, J.E.

    1995-01-10

    A turbine blade having a preestablished rate of thermal expansion is attached to a turbine wheel having a preestablished rate of thermal expansion being greater than the preestablished rate of thermal expansion of the turbine blade. The turbine blade has a root portion having a first groove and a second groove therein. The turbine wheel includes a plurality of openings in which the turbine blade is positioned. Each of the openings has a first groove and a second groove therein. The space or void formed between the first grooves and the second grooves has a plurality of spherical balls positioned therein. The plurality of spherical balls has a preestablished rate of thermal expansion being equal to the preestablished rate of thermal expansion of the turbine blade. 4 figures.

  18. Different perspectives on the sex-attachment link: towards an emotion-motivational account.

    PubMed

    Dewitte, Marieke

    2012-01-01

    Although the link between sex and attachment was made decades ago (Hazan & Shaver, 1987), theories on sexual and attachment functioning have been developed in relative isolation. Recent efforts to integrate both literatures have been complicated by the fact that the sex-attachment link has been approached from very different perspectives, including biological, evolutionary, developmental, cognitive, and social psychology approaches. Also, at the empirical level, research on sex and attachment lacks overarching synthesis. This article gives an overview of the most important theoretical ideas and empirical insights on sex and attachment. It starts with describing general models that approach the sex-attachment link from an evolutionary and neurobiological perspective. Then, it summarizes theoretical and empirical ideas of attachment theory and describes how attachment style differences are manifested in intimate and sexual relationships. Research so far has been limited to studying the predicted link between sex and attachment in terms of broad descriptives, and it would benefit the literature to specify the processes and pathways that mediate the sex-attachment link. After a short discussion of the functional similarities between the sexual and the attachment systems, the article describes some specific--dynamical--models that focus on the emotional and cognitive-motivational processes through which attachment schemas influence sexual experiences. Such an emotion-motivational perspective on sex and attachment can help to organize theoretical ideas and empirical findings and eventually promote an integrative view on how attachment dynamics can interact with sexual experiences. PMID:22380584

  19. Sentence-Level Attachment Prediction

    NASA Astrophysics Data System (ADS)

    Albakour, M.-Dyaa; Kruschwitz, Udo; Lucas, Simon

    Attachment prediction is the task of automatically identifying email messages that should contain an attachment. This can be useful to tackle the problem of sending out emails but forgetting to include the relevant attachment (something that happens all too often). A common Information Retrieval (IR) approach in analyzing documents such as emails is to treat the entire document as a bag of words. Here we propose a finer-grained analysis to address the problem. We aim at identifying individual sentences within an email that refer to an attachment. If we detect any such sentence, we predict that the email should have an attachment. Using part of the Enron corpus for evaluation we find that our finer-grained approach outperforms previously reported document-level attachment prediction in similar evaluation settings.

  20. Assessing attachment in school-age children.

    PubMed

    Crittenden, Patricia; Kozlowska, Kasia; Landini, Andrea

    2010-04-01

    The School-age Assessment of Attachment (SAA) is a newly developed clinical tool to identify pattern of attachment using the Dynamic-Maturational Model of attachment and adaptation (DMM). Seven picture cards were used to elicit fantasy stories and recalled episodes. The transcribed discourse was analyzed to yield one of 13 DMM attachment classifications, together with possible unresolved traumas and losses, and modifiers (depression and intrusions). In this article, we outline the steps necessary to validate an assessment tool, describe the development of the SAA, and report data from a preliminary clinical study testing the SAA's reliability, validity, and utility. Concurrent construct, familial, and discriminant validity were evaluated in terms of mental health status and exposure to danger on a sample of 5-12-year-old children, drawn from clinical ( n = 51) and normative (n = 40) populations. The SAA (a) differentiated children referred for psychiatric diagnosis from those in the normative population; (b) accounted for 31% of the variance (46% when family variables were added); (c) identified risk children in the normative sample; and (d) suggested risk factors associated with children's psychiatric disorder. PMID:20176770

  1. Soil properties and preferential solute transport at the field scale

    NASA Astrophysics Data System (ADS)

    Koestel, J. K.; Luong, N. M.; Nørgaard, T.; Vendelboe, A. L.; Moldrup, P.; Jarvis, N. J.; Lamandé, M.; Iversen, B. V.; Wollesen de Jonge, L.

    2012-04-01

    An important fraction of water flow and solute transport through soil takes place through preferential flow paths. Although this had been already observed in the nineteenth century, it had been forgotten by the scientific community until it was rediscovered during the 1970s. The awareness of the relevance of preferential flow was broadly re-established in the community by the early 1990s. However, since then, the notion remains widespread among soil scientists that the occurrence and strength of preferential flow cannot be predicted from measurable proxy variables such as soil properties or land management practices (e.g. Beven, K., 1991, Modeling preferential flow - an uncertain future, Preferential Flow, 1-11). In our study, we present evidence that disproves this notion. We evaluated breakthrough curve experiments under a constant irrigation rate of 1 cm/h conducted on 65 soil columns (20 cm diameter and 20 height) which had been sampled from an approximately 1 ha large loamy field-site in Silstrup, Denmark. We show that the holdback factor, which is an indicator for the strength of preferential transport, is strongly correlated to the bulk density, which in turn is correlated to the organic matter content. By applying multiple linear regression in a bootstrapping framework, we could estimate the holdback factor from the bulk density and the very fine sand fraction with a coefficient of determination of 0.65. Our results raise hopes that it is indeed possible to establish pedotransfer functions for soil susceptibility to preferential flow and transport.

  2. Preferential Interactions and the Effect of Protein PEGylation

    PubMed Central

    Holm, Louise Stenstrup; Thulstrup, Peter W.; Kasimova, Marina R.; van de Weert, Marco

    2015-01-01

    Background PEGylation is a strategy used by the pharmaceutical industry to prolong systemic circulation of protein drugs, whereas formulation excipients are used for stabilization of proteins during storage. Here we investigate the role of PEGylation in protein stabilization by formulation excipients that preferentially interact with the protein. Methodology/Principal Findings The model protein hen egg white lysozyme was doubly PEGylated on two lysines with 5 kDa linear PEGs (mPEG-succinimidyl valerate, MW 5000) and studied in the absence and presence of preferentially excluded sucrose and preferentially bound guanine hydrochloride. Structural characterization by far- and near-UV circular dichroism spectroscopy was supplemented by investigation of protein thermal stability with the use of differential scanning calorimetry, far and near-UV circular dichroism and fluorescence spectroscopy. It was found that PEGylated lysozyme was stabilized by the preferentially excluded excipient and destabilized by the preferentially bound excipient in a similar manner as lysozyme. However, compared to lysozyme in all cases the melting transition was lower by up to a few degrees and the calorimetric melting enthalpy was decreased to half the value for PEGylated lysozyme. The ratio between calorimetric and van’t Hoff enthalpy suggests that our PEGylated lysozyme is a dimer. Conclusion/Significance The PEGylated model protein displayed similar stability responses to the addition of preferentially active excipients. This suggests that formulation principles using preferentially interacting excipients are similar for PEGylated and non-PEGylated proteins. PMID:26230338

  3. Dissociative Electron Attachment

    NASA Astrophysics Data System (ADS)

    Arreola, Esmeralda; Esmeralda Arreola Collaboration; Leigh Hargreaves Collaboration

    Since the pioneering work of Boudiaffa et al., it has been understood that electrons, even with energies near or below the ionization threshold, are capable of initiating strand-breaks in human DNA. This discovery raised important questions for cancer treatments, since sub-ionizing electrons are known to be the most copiously produced secondary product of radiation therapy. But even to date these factors are largely excluded from dosimetry calculations. This lack of inclusion is, at least in part, certainly due to the dearth of fundamental data describing low-energy electron interactions with nucleotide molecules that form the basis of DNA. Understanding of how such slow electrons are able to damage DNA remains incomplete, but the strongly peaked nature of Boudiaffa et al.'s data gives strong hints at resonantly driven collision processes. DNA damage is therefore most likely driven by ``dissociative electron attachment'' (DEA). DEA is a rather complicated process to model due to the coupling of electronic and nuclear degrees of freedom in the molecule. At the California State University Fullerton, we are currently commissioning a new spectrometer to study dissociation channels, reaction rates and orientation effects in DEA collisions between slow electrons and nucleotide molecules. At the meeting we will present design parameters and commissioning data for this new apparatus.

  4. Electromagnetic attachment mechanism

    NASA Technical Reports Server (NTRS)

    Monford, Leo G., Jr. (Inventor)

    1992-01-01

    An electromagnetic attachment mechanism is disclosed for use as an end effector of a remote manipulator system. A pair of electromagnets, each with a U-shaped magnetic core with a pull-in coil and two holding coils, are mounted by a spring suspension system on a base plate of the mechanism housing with end pole pieces adapted to move through openings in the base plate when the attractive force of the electromagnets is exerted on a strike plate of a grapple fixture affixed to a target object. The pole pieces are spaced by an air gap from the strike plate when the mechanism first contacts the grapple fixture. An individual control circuit and power source is provided for the pull-in coil and one holding coil of each electromagnet. A back-up control circuit connected to the two power sources and a third power source is provided for the remaining holding coils. When energized, the pull-in coils overcome the suspension system and air gap and are automatically de-energized when the pole pieces move to grapple and impose a preload force across the grapple interface. A battery backup is a redundant power source for each electromagnet in each individual control circuit and is automatically connected upon failure of the primary source. A centerline mounted camera and video monitor are used in cooperation with a target pattern on the reflective surface of the strike plate to effect targeting and alignment.

  5. Fiber Attachment Module Experiment

    NASA Technical Reports Server (NTRS)

    Agostini, Reinaldo J.

    2014-01-01

    Hollow Fiber Membrane Bioreactors (HFMB) are ideal systems for biological pretreatment of wastewater, however, optimization is still underway. The Fiber Attachment Module Experiment (FAME) allows the simultaneous testing of potential materials, treatments on these and varying inoculums. Polydimethylsiloxane (PDMS), the material chosen for its ideal oxygen permeation properties, was treated with 1 sodium hydroxide 0.1 M ether for 18 seconds and ultraviolet (UV) irradiation oxygen plasma (OP) exposure for 1 hour. Preliminary chemistry and visual data indicate promising treatments when using OP and sodium hydroxide as treatments for PDMS fibers; however, due to the biological nature of the experiment, time is a constraint. Sodium hydroxide treatment chemistry data shows nitrification is occurring as urea and ammonia are decreasing and nitrite is increasing. A higher amount of biofilm can also be observed for this particular case. During the final two weeks of the internship x-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR) and acridine orange (AO) cell counts will be employed for treatment effectiveness on the first batch of treatments (ether and sodium hydroxide). These same strategies will be used for the second batch of experiments due in four weeks (2nd week of August).

  6. PREDICTING PREFERENTIAL ADSORPTION OF ORGANICS BY ACTIVATED CARBON

    EPA Science Inventory

    Preferential adsorption of organic compounds onto activated carbon from dilute aqueous solutions was studied to develop a comprehensive theoretical basis for predicting adsorption of multicomponent solutes. The research program investigates why some solutes are strong adsorbers, ...

  7. Crossover phenomena of percolation transition in evolution networks with hybrid attachment.

    PubMed

    Chen, Xiaolong; Yang, Chun; Zhong, Linfeng; Tang, Ming

    2016-08-01

    A first-order percolation transition, called explosive percolation, was recently discovered in evolution networks with random edge selection under a certain restriction. For many real world networks, the mechanism of preferential attachment plays a significant role in the formation of heterogeneous structures, but the network percolation in evolution process with preferential attachment has not yet been concerned. We propose a tunable network percolation model by introducing a hybrid mechanism of edge selection into the Bohman-Frieze-Wormald model, in which a parameter adjusts the relative weights between random and preferential selections. A large number of simulations indicate that there exist crossover phenomena of percolation transition by adjusting the parameter in the evolution processes. When the strategy of selecting a candidate edge is dominated by random selection, a single discontinuous percolation transition occurs. When a candidate edge is selected more preferentially based on nodes degree, the size of the largest component undergoes multiple discontinuous jumps, which exhibits a peculiar difference from the network percolation of random selection with a certain restriction. Besides, the percolation transition becomes continuous when the candidate edge is selected completely preferentially. PMID:27586610

  8. Attachment in Preschool Deaf Children.

    ERIC Educational Resources Information Center

    Greenberg, Mark T.

    A study was designed to examine the attachment behavior of 28 preschool deaf children and their hearing mothers and compare their patterns of behavior to previous reports of normal hearing dyads, and within this sample examine the relationship between communicative ability and phase of attachment. The sample was subdivided by communication…

  9. Mobilization and preferential transport of soil particles during infiltration: A core-scale modeling approach

    NASA Astrophysics Data System (ADS)

    Majdalani, Samer; Michel, Eric; di Pietro, Liliana; Angulo-Jaramillo, Rafael; Rousseau, Marine

    2007-05-01

    Understanding particle movement in soils is a major concern for both geotechnics and soil physics with regard to environmental protection and water resources management. This paper describes a model for mobilization and preferential transport of soil particles through structured soils. The approach combines a kinematic-dispersive wave model for preferential water flow with a convective-dispersive equation subject to a source/sink term for particle transport and mobilization. Particle detachment from macropore walls is considered during both the steady and transient water flow regimes. It is assumed to follow first-order kinetics with a varying detachment efficiency, which depends on the history of the detachment process. Estimates of model parameters are obtained by comparing simulations with experimental particle breakthrough curves obtained during infiltrations through undisturbed soil columns. Both water flux and particle concentrations are satisfactorily simulated by the model. Particle mobilization parameters favoring both attachment and detachment of particles are related to the incoming solution ionic strength by a Fermi-type function.

  10. Preferential solvation of lysozyme in dimethyl sulfoxide/water binary mixture probed by terahertz spectroscopy.

    PubMed

    Das, Dipak Kumar; Patra, Animesh; Mitra, Rajib Kumar

    2016-09-01

    We report the changes in the hydration dynamics around a model protein hen egg white lysozyme (HEWL) in water-dimethyl sulfoxide (DMSO) binary mixture using THz time domain spectroscopy (TTDS) technique. DMSO molecules get preferentially solvated at the protein surface, as indicated by circular dichroism (CD) and Fourier transform infrared (FTIR) study in the mid-infrared region, resulting in a conformational change in the protein, which consequently modifies the associated hydration dynamics. As a control we also study the collective hydration dynamics of water-DMSO binary mixture and it is found that it follows a non-ideal behavior owing to the formation of DMSO-water clusters. It is observed that the cooperative dynamics of water at the protein surface does follow the DMSO-mediated conformational modulation of the protein. PMID:27372901

  11. Preferential intracellular pH regulation: hypotheses and perspectives.

    PubMed

    Shartau, Ryan B; Baker, Daniel W; Crossley, Dane A; Brauner, Colin J

    2016-08-01

    The regulation of vertebrate acid-base balance during acute episodes of elevated internal PCO2  is typically characterized by extracellular pH (pHe) regulation. Changes in pHe are associated with qualitatively similar changes in intracellular tissue pH (pHi) as the two are typically coupled, referred to as 'coupled pH regulation'. However, not all vertebrates rely on coupled pH regulation; instead, some preferentially regulate pHi against severe and maintained reductions in pHe Preferential pHi regulation has been identified in several adult fish species and an aquatic amphibian, but never in adult amniotes. Recently, common snapping turtles were observed to preferentially regulate pHi during development; the pattern of acid-base regulation in these species shifts from preferential pHi regulation in embryos to coupled pH regulation in adults. In this Commentary, we discuss the hypothesis that preferential pHi regulation may be a general strategy employed by vertebrate embryos in order to maintain acid-base homeostasis during severe acute acid-base disturbances. In adult vertebrates, the retention or loss of preferential pHi regulation may depend on selection pressures associated with the environment inhabited and/or the severity of acid-base regulatory challenges to which they are exposed. We also consider the idea that the retention of preferential pHi regulation into adulthood may have been a key event in vertebrate evolution, with implications for the invasion of freshwater habitats, the evolution of air breathing and the transition of vertebrates from water to land. PMID:27489212

  12. Universal precision sine bar attachment

    NASA Technical Reports Server (NTRS)

    Mann, Franklin D. (Inventor)

    1989-01-01

    This invention relates to an attachment for a sine bar which can be used to perform measurements during lathe operations or other types of machining operations. The attachment can be used for setting precision angles on vises, dividing heads, rotary tables and angle plates. It can also be used in the inspection of machined parts, when close tolerances are required, and in the layout of precision hardware. The novelty of the invention is believed to reside in a specific versatile sine bar attachment for measuring a variety of angles on a number of different types of equipment.

  13. Everything You Want To Know about Attachment.

    ERIC Educational Resources Information Center

    Honig, Alice Sterling

    This paper discusses infant attachment, which it defines as a long-lasting emotional bond revealed when a child under stress seeks out and tries to stay close to a specific figure. The paper addresses: (1) What is attachment? Who are the pioneers in attachment theory?; (2) How do we notice attachment in action?; (3) Is attachment the only…

  14. The Intergenerational Transmission of Attachment Behavior.

    ERIC Educational Resources Information Center

    Clubb, Richard D.; And Others

    This study examines the relationship between parent-child attachment and parental attachment styles. It is hypothesized that: (1) parental attachment styles are transmitted to the infant through parent-child and parent-parent interaction; and (2) parental attachment styles are reflected in parent-child attachment. Some research supports the idea…

  15. Attachment to Caregivers and Type 1 Diabetes in Children

    PubMed Central

    DROBNIČ RADOBULJAC, Maja; SHMUELI-GOETZ, Yael

    2015-01-01

    Attachment is a behavioral and physiological system, which enables individual’s dynamic adaptation to its environment. Attachment develops in close interaction between an infant and his/her mother, plays an important role in the development of the infant’s brain, and influences the quality of interpersonal relationships throughout life. Security of attachment is believed to influence individual response to stress, exposing insecurely organized individuals to deregulated autonomic nervous system and exaggerated hypothalamic-pituitary-adrenal activity, which, in turn, produces increased and prolonged exposure to stress-hormones. Such stress responses may have considerable implications for the development of diverse health-risk conditions, such as insulin resistance and hyperlipidemia, shown by numerous studies. Although the mechanisms are not yet fully understood, there is compelling evidence highlighting the role of psychological stress in the development of type 1 diabetes (T1D). One of the possible contributing factors for the development of T1D may be the influence of attachment security on individual stress reactivity. Thus, the suggestion is that insecurely attached individuals are more prone to experience increased and prolonged influence of stress hormones and other mechanisms causing pancreatic beta-cell destruction. The present paper opens with a short overview of the field of attachment in children, the principal attachment classifications and their historic development, describes the influence of attachment security on individual stress-reactivity and the role of the latter in the development of T1D. Following is a review of recent literature on the attachment in patients with T1D with a conclusion of a proposed role of attachment organization in the etiology of T1D.

  16. A Hybrid Analytical/Numerical Model for the Characterization of Preferential Flow Path with Non-Darcy Flow

    PubMed Central

    Wang, Sen; Feng, Qihong; Han, Xiaodong

    2013-01-01

    Due to the long-term fluid-solid interactions in waterflooding, the tremendous variation of oil reservoir formation parameters will lead to the widespread evolution of preferential flow paths, thereby preventing the further enhancement of recovery efficiency because of unstable fingering and premature breakthrough. To improve oil recovery, the characterization of preferential flow paths is essential and imperative. In efforts that have been previously documented, fluid flow characteristics within preferential paths are assumed to obey Darcy's equation. However, the occurrence of non-Darcy flow behavior has been increasingly suggested. To examine this conjecture, the Forchheimer number with the inertial coefficient estimated from different empirical formulas is applied as the criterion. Considering a 10% non-Darcy effect, the fluid flow in a preferential path may do experience non-Darcy behavior. With the objective of characterizing the preferential path with non-Darcy flow, a hybrid analytical/numerical model has been developed to investigate the pressure transient response, which dynamically couples a numerical model describing the non-Darcy effect of a preferential flow path with an analytical reservoir model. The characteristics of the pressure transient behavior and the sensitivities of corresponding parameters have also been discussed. In addition, an interpretation approach for pressure transient testing is also proposed, in which the Gravitational Search Algorithm is employed as a non-linear regression technology to match measured pressure with this hybrid model. Examples of applications from different oilfields are also presented to illustrate this method. This cost-effective approach provides more accurate characterization of a preferential flow path with non-Darcy flow, which will lay a solid foundation for the design and operation of conformance control treatments, as well as several other Enhanced Oil Recovery projects. PMID:24386224

  17. Phosphorus Speciation and Sorption Processes in Preferential flow paths and Soil Matrix in Forested Podzolic Till Soil

    NASA Astrophysics Data System (ADS)

    Saastamoinen, S.; Laine-Kaulio, H.; Klöve, B.

    2009-04-01

    The importance of preferential flow paths in nutrient leaching and subsurface transport has been identified in several studies mainly on agricultural soils. In forest soils research, decayed root channels, stone surfaces and other secondary soil structures have shown to affect unsaturated flow in glacial till soil. Until recently, the focus has been on nitrogen and carbon dynamics in the preferential flow paths. Preferential flow may also have a fundamental role in phosphorus (P) sorption processes and transport from forested till soils to surface waters. The main objectives of this study were to determine how preferential flow paths affect to P speciation, sorption and leaching in forested podzolic till soil. Field experiments were conducted in mixed coniferous forest, with soil type of glacial sandy till classified as Haplic Podzol. The first experiment was conducted in Ranua, Northern Finland. The preferential flow paths were identified by introducing Acid Blue 9 dye tracer to a 1 m2 study plot. The soil profile was vertically sliced and samples were collected from the stained preferential flow paths and unstained soil matrix. Ammonium-oxalate extracted trace elements and P, total and inorganic P, inorganic P fractions and organic P forms (31P-NMR spectroscopy) were analyzed from the samples. In the second experiment in Sotkamo, Eastern Finland, three 1 m2 study plots were selected from a forested hillslope: top, middle and bottom slope. The detection of preferential flow paths and the sampling procedure was identical to the first plot experiment. Samples were analyzed for ammonium-oxalate extracted trace elements and P. Also, the effect of reaction time, P concentration and temperature on the sorption process in preferential flow paths and soil matrix was studied by kinetic batch-type sorption experiments. Stone surfaces were the most dominant preferential flow paths and contained lower oxalate-extracted and total P concentrations than the soil matrix in all

  18. New line pipe resists preferential corrosion at welds

    SciTech Connect

    Endo, Sigeru; Fujita, Sakae; Nagae, Moriyasu; Hirano, Osamu

    1997-03-17

    Line pipe with preferential corrosion resistance in the welded joint in CO{sub 2}-containing gas and oil environments has been produced and delivered for use in the North Sea. NKK Corp., Tokyo, developed the pipe by taking into consideration the mechanism of preferential corrosion. The chemistry was optimized to prevent preferential corrosion of both heat-affected zone (HAZ) and weld metal. The project also developed girth-welding consumables for the pipe. Based on test results, 6,000 tons of the preferential-corrosion-resistant pipes were mass produced for a North Sea marine pipeline. Overall, the testing program led to the following conclusions: the immersed potential of the HAZ was clearly higher than that of the base metal in the lower S, Cu, and Ni-containing steels with a bainitic microstructure. Hence, preferential corrosion of the HAZ of this type of steel is unlikely in a CO{sub 2} environment. The sign of the galvanic current density is positive when the chemical composition difference between the weld an base metals in Cu and Ni are greater than 0.5% and that of Mo is above 0.05%.

  19. Attachment at work and performance.

    PubMed

    Neustadt, Elizabeth A; Chamorro-Premuzic, Tomas; Furnham, Adrian

    2011-09-01

    This paper examines the relations between self-reported attachment orientation at work and personality, self-esteem, trait emotional intelligence (aka emotional self-efficacy), and independently assessed career potential and job performance. Self-report data were collected from 211 managers in an international business in the hospitality industry; independent assessments of these managers' job performance and career potential were separately obtained from the organization. A self-report measure of romantic attachment was adapted for application in the work context; a two-factor solution was found for this measure. Secure/autonomous attachment orientation at work was positively related to self-esteem, trait emotional intelligence, extraversion, agreeableness, and conscientiousness, and also to job performance. Not only was secure/autonomous attachment orientation at work statistically predictive of job performance, but the new measure also made a distinct contribution, beyond conscientiousness, to this prediction. PMID:21838647

  20. Adult attachment and declining birthrates.

    PubMed

    Draper, Thomas W; Holman, Thomas B; White, Whitney; Grandy, Shannon

    2007-02-01

    Attachment scores for 658 young adults living in the U.S.A. were obtained using the Experiences in Close Relationships scale. The participants came from a subsample of the RELATE data set, who had also filled out the adult attachment measure. Those young adults living in Utah County, Utah, an area of the country with a higher than normal birthrate (88% members of the Church of Jesus Christ of Latter-day Saints), also had higher than average adult attachment scores. While the methodology was not sufficient to assess causal direction nor eliminate the possibility of unidentified influences, an undiscussed psychological factor, adult attachment, may play a role in the numerical declines observed among nonimmigrant communities in the USA and Europe. PMID:17450996

  1. Social attachments and traumatic stress

    PubMed Central

    Bryant, Richard A.

    2016-01-01

    The extent to which we engage with our social world has been central to our survival as a species and, accordingly, is relevant to how we cope with trauma and adversity. This review summarises current knowledge about the importance of social connections from an evolutionary perspective, as well as integrating this with a discussion of prevailing attachment theories. Experimental research supporting the potential benefit of attachments for managing adversity are presented, along with a review of how these benefits are moderated by individual differences in attachment style. The potential impact of trauma on attachment systems, and the manner in which this can compound trauma stress is discussed. Finally, a broader overview of social network analysis is introduced and it is proposed that a more sociocentric framework of trauma response would promote a fuller understanding of how social processes moderate trauma response. PMID:26996531

  2. Preferential sampling and Bayesian geostatistics: Statistical modeling and examples.

    PubMed

    Cecconi, Lorenzo; Grisotto, Laura; Catelan, Dolores; Lagazio, Corrado; Berrocal, Veronica; Biggeri, Annibale

    2016-08-01

    Preferential sampling refers to any situation in which the spatial process and the sampling locations are not stochastically independent. In this paper, we present two examples of geostatistical analysis in which the usual assumption of stochastic independence between the point process and the measurement process is violated. To account for preferential sampling, we specify a flexible and general Bayesian geostatistical model that includes a shared spatial random component. We apply the proposed model to two different case studies that allow us to highlight three different modeling and inferential aspects of geostatistical modeling under preferential sampling: (1) continuous or finite spatial sampling frame; (2) underlying causal model and relevant covariates; and (3) inferential goals related to mean prediction surface or prediction uncertainty. PMID:27566774

  3. 10 CFR 75.15 - Facility attachments.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... Accounting and Control for Facilities § 75.15 Facility attachments. (a) The Facility Attachment or... under Article 39(b) of the main text of the Safeguards Agreement, do not have Facility Attachments...

  4. Inverse Simulation of Field Infiltration Experiment Counting Preferential Flow

    NASA Astrophysics Data System (ADS)

    Zumr, David; Snehota, Michal; Nemcova, Renata; Dohnal, Michal; Cislerova, Milena

    2010-05-01

    The field tension and ponded infiltration experiments were conducted to monitor and describe irregularities of moisture propagation and to estimate the soil hydraulic properties (Distric Cambisol, Korkusova Hut, Sumava). On these soils the preferential pathways have been observed in several scales with the use of dye tracers, MRI and CT imaging. Preferential behavior was detected also during laboratory infiltration experiments. The flow irregularities are credited to variable air entrapment at the beginning of infiltrations. The field infiltration experiment was carried out in a shallow pit for a period of one day. The upper boundary condition was controlled by the tension disk infiltrometer, the propagation of a water front was monitored by two tensiometers installed in two depths below the infiltration disk. The propagation of saline solution front during ponded infiltration was visualized with high resolution electrical resistivity tomography (ERT). Infiltration experiments were monitored with TDR probes, tensiometers and ERT. Zones of preferential flow were determined through analyses of photographs taken during laboratory dye tracer infiltration experiments performed on undisturbed soil samples. Connectivity, volumetric ratio and spatial development of preferential pathways were evaluated as the necessary information for numerical simulations of flow using dual-permeability approach. 2D axisymetric numerical simulations were conducted to evaluate the results of the experiment. The parameter estimator PEST coupled with the simulation code S2D_DUAL (Vogel et al., 2000) were employed. Two different approaches were used: 1. Single-domain approach based on Richards' equation. 2. Dual-permeability approach based on two interacting water flow domains (matrix and preferential domains), each governed by one Richards' equation. Concerning the existence of preferential flow on investigated soil, the dual-permeability model gives a better picture of the flow regime. The

  5. Laboratory-based observations of capillary barriers and preferential flow in layered snow

    NASA Astrophysics Data System (ADS)

    Avanzi, F.; Hirashima, H.; Yamaguchi, S.; Katsushima, T.; De Michele, C.

    2015-12-01

    Several evidences are nowadays available that show how the effects of capillary gradients and preferential flow on water transmission in snow may play a more important role than expected. To observe these processes and to contribute in their characterization, we performed observations on the development of capillary barriers and preferential flow patterns in layered snow during cold laboratory experiments. We considered three different layering (all characterized by a finer-over-coarser texture in grain size) and three different water input rates. Nine samples of layered snow were sieved in a cold laboratory, and subjected to a constant supply of dyed tracer. By means of visual inspection, horizontal sectioning and liquid water content measurements, the processes of ponding and preferential flow were characterized as a function of texture and water input rate. The dynamics of each sample were replicated using the multi-layer physically-based SNOWPACK model. Results show that capillary barriers and preferential flow are relevant processes ruling the speed of liquid water in stratified snow. Ponding is associated with peaks in LWC at the boundary between the two layers equal to ~ 33-36 vol. % when the upper layer is composed by fine snow (grain size smaller than 0.5 mm). The thickness of the ponding layer at the textural boundary is between 0 and 3 cm, depending on sample stratigraphy. Heterogeneity in water transmission increases with grain size, while we do not observe any clear dependency on water input rate. The extensive comparison between observed and simulated LWC profiles by SNOWPACK (using an approximation of Richards Equation) shows high performances by the model in estimating the LWC peak over the boundary, while water speed in snow is underestimated by the chosen water transport scheme.

  6. Childhood sexual abuse and attachment: An intergenerational perspective

    PubMed Central

    Kwako, Laura E.; Noll, Jennie G.; Putnam, Frank W.; Trickett, Penelope K.

    2011-01-01

    Childhood sexual abuse (CSA) is a recognized risk factor for various negative outcomes in adult survivors and their offspring. We used the Dynamic-Maturational Model of attachment theory as a framework for exploring the impact of maternal CSA on children’s attachment relationships in the context of a longitudinal sample of adult survivors of CSA and non-abused comparison mothers and their children. Results indicated that children of CSA survivors were more likely to have extreme strategies of attachment than the children of non-abused mothers. However, because both groups were at socioeconomic risk, both were typified by anxious attachment. Explanations for findings and implications for children’s development are explored. PMID:20603427

  7. Childhood sexual abuse and attachment: An intergenerational perspective.

    PubMed

    Kwako, Laura E; Noll, Jennie G; Putnam, Frank W; Trickett, Penelope K

    2010-07-01

    Childhood sexual abuse (CSA) is a recognized risk factor for various negative outcomes in adult survivors and their offspring. We used the Dynamic-Maturational Model of attachment theory as a framework for exploring the impact of maternal CSA on children's attachment relationships in the context of a longitudinal sample of adult survivors of CSA and non-abused comparison mothers and their children. Results indicated that children of CSA survivors were more likely to have extreme strategies of attachment than the children of non-abused mothers. However, because both groups were at socioeconomic risk, both were typified by anxious attachment. Explanations for findings and implications for children's development are explored. PMID:20603427

  8. Declustering of clustered preferential sampling for histogram and semivariogram inference

    USGS Publications Warehouse

    Olea, R.A.

    2007-01-01

    Measurements of attributes obtained more as a consequence of business ventures than sampling design frequently result in samplings that are preferential both in location and value, typically in the form of clusters along the pay. Preferential sampling requires preprocessing for the purpose of properly inferring characteristics of the parent population, such as the cumulative distribution and the semivariogram. Consideration of the distance to the nearest neighbor allows preparation of resampled sets that produce comparable results to those from previously proposed methods. Clustered sampling of size 140, taken from an exhaustive sampling, is employed to illustrate this approach. ?? International Association for Mathematical Geology 2007.

  9. Preferential Sampling and Small-Scale Clustering of Gyrotactic Microswimmers in Turbulence.

    PubMed

    Gustavsson, K; Berglund, F; Jonsson, P R; Mehlig, B

    2016-03-11

    Recent studies show that spherical motile microorganisms in turbulence subject to gravitational torques gather in down-welling regions of the turbulent flow. By analyzing a statistical model we analytically compute how shape affects the dynamics, preferential sampling, and small-scale spatial clustering. We find that oblong organisms may spend more time in up-welling regions of the flow, and that all organisms are biased to regions of positive fluid-velocity gradients in the upward direction. We analyze small-scale spatial clustering and find that oblong particles may either cluster more or less than spherical ones, depending on the strength of the gravitational torques. PMID:27015512

  10. Preferential Sampling and Small-Scale Clustering of Gyrotactic Microswimmers in Turbulence

    NASA Astrophysics Data System (ADS)

    Gustavsson, K.; Berglund, F.; Jonsson, P. R.; Mehlig, B.

    2016-03-01

    Recent studies show that spherical motile microorganisms in turbulence subject to gravitational torques gather in down-welling regions of the turbulent flow. By analyzing a statistical model we analytically compute how shape affects the dynamics, preferential sampling, and small-scale spatial clustering. We find that oblong organisms may spend more time in up-welling regions of the flow, and that all organisms are biased to regions of positive fluid-velocity gradients in the upward direction. We analyze small-scale spatial clustering and find that oblong particles may either cluster more or less than spherical ones, depending on the strength of the gravitational torques.

  11. Dynamics of Sun5 Localization during Spermatogenesis in Wild Type and Dpy19l2 Knock-Out Mice Indicates That Sun5 Is Not Involved in Acrosome Attachment to the Nuclear Envelope

    PubMed Central

    Yassine, Sandra; Escoffier, Jessica; Nahed, Roland Abi; Pierre, Virginie; Karaouzene, Thomas; Ray, Pierre F.; Arnoult, Christophe

    2015-01-01

    The acrosome is an organelle that is central to sperm physiology and a defective acrosome biogenesis leads to globozoospermia, a severe male infertility. The identification of the actors involved in acrosome biogenesis is therefore particularly important to decipher the molecular pathogeny of globozoospermia. We recently showed that a defect in the DPY19L2 gene is present in more than 70% of globozoospermic men and demonstrated that Dpy19l2, located in the inner nuclear membrane, is the first protein involved in the attachment of the acrosome to the nuclear envelope (NE). SUN proteins serve to link the nuclear envelope to the cytoskeleton and are therefore good candidates to participate in acrosome-nucleus attachment, potentially by interacting with DPY19L2. In order to characterize new actors of acrosomal attachment, we focused on Sun5 (also called Spag4l), which is highly expressed in male germ cells, and investigated its localization during spermatogenesis. Using immunohistochemistry and Western blot experiments in mice, we showed that Sun5 transits through different cellular compartments during meiosis. In pachytene spermatocytes, it is located in a membranous compartment different to the reticulum. In round spermatids, it progresses to the Golgi and the NE before to be located to the tail/head junction in epididymal sperm. Interestingly, we demonstrate that Sun5 is not, as initially reported, facing the acrosome but is in fact excluded from this zone. Moreover, we show that in Dpy19l2 KO spermatids, upon the detachment of the acrosome, Sun5 relocalizes to the totality of the NE suggesting that the acrosome attachment excludes Sun5 from the NE facing the acrosome. Finally, Western-blot experiments demonstrate that Sun5 is glycosylated. Overall, our work, associated with other publications, strongly suggests that the attachment of the acrosome to the nucleus does not likely depend on the formation of SUN complexes. PMID:25775128

  12. Attachment of Pathogenic Prion Protein to Model Oxide Surfaces

    PubMed Central

    Jacobson, Kurt H.; Kuech, Thomas R.; Pedersen, Joel A.

    2014-01-01

    Prions are the infectious agents in the class of fatal neurodegenerative diseases known as transmissible spongiform encephalopathies, which affect humans, deer, sheep, and cattle. Prion diseases of deer and sheep can be transmitted via environmental routes, and soil is has been implicated in the transmission of these diseases. Interaction with soil particles is expected to govern the transport, bioavailability and persistence of prions in soil environments. A mechanistic understanding of prion interaction with soil components is critical for understanding the behavior of these proteins in the environment. Here, we report results of a study to investigate the interactions of prions with model oxide surfaces (Al2O3, SiO2) using quartz crystal microbalance with dissipation monitoring and optical waveguide light mode spectroscopy. The efficiency of prion attachment to Al2O3 and SiO2 depended strongly on pH and ionic strength in a manner consistent with electrostatic forces dominating interaction with these oxides. The N-terminal portion of the protein appeared to facilitate attachment to Al2O3 under globally electrostatically repulsive conditions. We evaluated the utility of recombinant prion protein as a surrogate for prions in attachment experiments and found that its behavior differed markedly from that of the infectious agent. Our findings suggest that prions preferentially associate with positively charged mineral surfaces in soils (e.g., iron and aluminum oxides). PMID:23611152

  13. 19 CFR 10.243 - Articles eligible for preferential treatment.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 19 Customs Duties 1 2012-04-01 2012-04-01 false Articles eligible for preferential treatment. 10.243 Section 10.243 Customs Duties U.S. CUSTOMS AND BORDER PROTECTION, DEPARTMENT OF HOMELAND SECURITY; DEPARTMENT OF THE TREASURY ARTICLES CONDITIONALLY FREE, SUBJECT TO A REDUCED RATE, ETC. Andean Trade Promotion and Drug Eradication Act Apparel...

  14. 19 CFR 10.213 - Articles eligible for preferential treatment.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 19 Customs Duties 1 2013-04-01 2013-04-01 false Articles eligible for preferential treatment. 10.213 Section 10.213 Customs Duties U.S. CUSTOMS AND BORDER PROTECTION, DEPARTMENT OF HOMELAND SECURITY; DEPARTMENT OF THE TREASURY ARTICLES CONDITIONALLY FREE, SUBJECT TO A REDUCED RATE, ETC. Textile and Apparel Articles Under the African Growth...

  15. 19 CFR 10.213 - Articles eligible for preferential treatment.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 19 Customs Duties 1 2012-04-01 2012-04-01 false Articles eligible for preferential treatment. 10.213 Section 10.213 Customs Duties U.S. CUSTOMS AND BORDER PROTECTION, DEPARTMENT OF HOMELAND SECURITY; DEPARTMENT OF THE TREASURY ARTICLES CONDITIONALLY FREE, SUBJECT TO A REDUCED RATE, ETC. Textile and Apparel Articles Under the African Growth...

  16. 19 CFR 10.243 - Articles eligible for preferential treatment.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 19 Customs Duties 1 2013-04-01 2013-04-01 false Articles eligible for preferential treatment. 10.243 Section 10.243 Customs Duties U.S. CUSTOMS AND BORDER PROTECTION, DEPARTMENT OF HOMELAND SECURITY; DEPARTMENT OF THE TREASURY ARTICLES CONDITIONALLY FREE, SUBJECT TO A REDUCED RATE, ETC. Andean Trade Promotion and Drug Eradication Act Apparel...

  17. 19 CFR 10.223 - Articles eligible for preferential treatment.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 19 Customs Duties 1 2013-04-01 2013-04-01 false Articles eligible for preferential treatment. 10.223 Section 10.223 Customs Duties U.S. CUSTOMS AND BORDER PROTECTION, DEPARTMENT OF HOMELAND SECURITY; DEPARTMENT OF THE TREASURY ARTICLES CONDITIONALLY FREE, SUBJECT TO A REDUCED RATE, ETC. United States-Caribbean Basin Trade Partnership Act...

  18. 19 CFR 10.223 - Articles eligible for preferential treatment.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 19 Customs Duties 1 2012-04-01 2012-04-01 false Articles eligible for preferential treatment. 10.223 Section 10.223 Customs Duties U.S. CUSTOMS AND BORDER PROTECTION, DEPARTMENT OF HOMELAND SECURITY; DEPARTMENT OF THE TREASURY ARTICLES CONDITIONALLY FREE, SUBJECT TO A REDUCED RATE, ETC. United States-Caribbean Basin Trade Partnership Act...

  19. Infants' Preferential Attention to Sung and Spoken Stimuli

    ERIC Educational Resources Information Center

    Costa-Giomi, Eugenia; Ilari, Beatriz

    2014-01-01

    Caregivers and early childhood teachers all over the world use singing and speech to elicit and maintain infants' attention. Research comparing infants' preferential attention to music and speech is inconclusive regarding their responses to these two types of auditory stimuli, with one study showing a music bias and another one…

  20. 19 CFR 10.213 - Articles eligible for preferential treatment.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 19 Customs Duties 1 2014-04-01 2014-04-01 false Articles eligible for preferential treatment. 10.213 Section 10.213 Customs Duties U.S. CUSTOMS AND BORDER PROTECTION, DEPARTMENT OF HOMELAND SECURITY; DEPARTMENT OF THE TREASURY ARTICLES CONDITIONALLY FREE, SUBJECT TO A REDUCED RATE, ETC. Textile and...

  1. On the Effect of Preferential Sampling in Spatial Prediction

    EPA Science Inventory

    The choice of the sampling locations in a spatial network is often guided by practical demands. In particular, typically, locations are preferentially chosen to capture high values of a response, for example, air pollution levels in environmental monitoring. Then, model estimatio...

  2. Voluntary Affirmative Action and Preferential Treatment: Legal and Research Implications.

    ERIC Educational Resources Information Center

    Kleiman, Lawrence S.; Faley, Robert H.

    1988-01-01

    Reviews recent Supreme Court decisions stemming from implementation of voluntary affirmative action plans (AAPs) that include preferential treatment as a remedy. Evidence and proof required to establish and defend against reverse discrimination claims are identified. Examines research on potential effects of voluntary AAPs on important…

  3. Preferential Policies and Secondary School Attainment in Peninsular Malaysia.

    ERIC Educational Resources Information Center

    Pong, Suet-ling

    1993-01-01

    Examines the effects of Malaysia's preferential educational policies regarding secondary school attainment for the nation's three ethnic groups. Investigates trends in gender and socioeconomic differences within each ethnic group. Finds that, over time, Malays were increasingly more likely to attain secondary school than were non-Malays. (CFR)

  4. PREFERENTIAL RADON TRANSPORT THROUGH HIGHLY PERMEABLE CHANNELS IN SOILS

    EPA Science Inventory

    The paper discusses preferential radon transport through highly permeable channels in soils. Indoor radon levels (that can pose a serious health risk) can be dramatically increased by air that is drawn into buildings through pipe penetrations that connect to permeable channels in...

  5. Estimating Preferential Flow in Karstic Aquifers Using Statistical Mixed Models

    PubMed Central

    Anaya, Angel A.; Padilla, Ingrid; Macchiavelli, Raul; Vesper, Dorothy J.; Meeker, John D.; Alshawabkeh, Akram N.

    2013-01-01

    Karst aquifers are highly productive groundwater systems often associated with conduit flow. These systems can be highly vulnerable to contamination, resulting in a high potential for contaminant exposure to humans and ecosystems. This work develops statistical models to spatially characterize flow and transport patterns in karstified limestone and determines the effect of aquifer flow rates on these patterns. A laboratory-scale Geo-HydroBed model is used to simulate flow and transport processes in a karstic limestone unit. The model consists of stainless-steel tanks containing a karstified limestone block collected from a karst aquifer formation in northern Puerto Rico. Experimental work involves making a series of flow and tracer injections, while monitoring hydraulic and tracer response spatially and temporally. Statistical mixed models are applied to hydraulic data to determine likely pathways of preferential flow in the limestone units. The models indicate a highly heterogeneous system with dominant, flow-dependent preferential flow regions. Results indicate that regions of preferential flow tend to expand at higher groundwater flow rates, suggesting a greater volume of the system being flushed by flowing water at higher rates. Spatial and temporal distribution of tracer concentrations indicates the presence of conduit-like and diffuse flow transport in the system, supporting the notion of both combined transport mechanisms in the limestone unit. The temporal response of tracer concentrations at different locations in the model coincide with, and confirms the preferential flow distribution generated with the statistical mixed models used in the study. PMID:23802921

  6. Predicting Alcohol, Cigarette, and Marijuana Use from Preferential Music Consumption

    ERIC Educational Resources Information Center

    Oberle, Crystal D.; Garcia, Javier A.

    2015-01-01

    This study investigated whether use of alcohol, cigarettes, and marijuana may be predicted from preferential consumption of particular music genres. Undergraduates (257 women and 78 men) completed a questionnaire assessing these variables. Partial correlation analyses, controlling for sensation-seeking tendencies and behaviors, revealed that…

  7. Partner attachment and interpersonal characteristics.

    PubMed

    Kilmann, Peter R; Finch, Holmes; Parnell, Michele M; Downer, Jason T

    2013-01-01

    This study investigated partner attachment and interpersonal characteristics in 134 nonclinical couples in long-term marriages. Irrespective of gender, spouses with greater anxiety over abandonment or discomfort with closeness endorsed dysfunctional relationship beliefs to a greater extent. On the anxiety over abandonment dimension, husbands with higher scores were rated less aggressive, less controlling, and more rebellious, whereas wives with higher scores were rated more dependent, more self-critical, and less competitive. Husbands higher on discomfort with closeness were rated less cooperative and responsible and were rated more aggressive and rebellious. Matched secure couples reported lower marital dissatisfaction than matched insecure or mismatched couples. Future research should contrast samples of nonclinical and clinical couples by marital duration to identify specific partner behaviors that are likely to foster marital dissatisfaction within particular attachment pairings. The authors' findings suggest the importance of marital therapists being attuned to the attachment-related beliefs and interpersonal styles uniquely operating within each couple. PMID:23252639

  8. Do Karstic Unsaturated Zones Have the Fastest Preferential Flow?

    NASA Astrophysics Data System (ADS)

    Nimmo, J. R.; Perkins, K. S.

    2013-12-01

    There is strong evidence that unsaturated-zone travel times for preferential flow, unlike those for diffuse flow, mostly fall within a relatively small range, even for a wide variety of media and conditions [Nimmo, 2007, Water Resources Research]. We have calculated travel times for preferential flow observations published in the last seven years, finding a range of travel velocities with a greater maximum than was previously recognized. The instances of faster transport, however, are predominantly for karst or other materials in which water flow may strongly influence the creation and development of preferential flow paths. These findings motivate a hypothesis: in media where the matrix is soluble, erodible, or otherwise vulnerable to enlargement by flowing water, this flow acts to reduce flow impediments within a macropore network. This might be thought of as a sculpting process in which water carves its conduit into a smoother, larger, less constrictive shape, as discussed in connection with soil pipes [Jones, 2010, Hydrological Processes]. Known developmental processes of karst and epikarst are consistent with this hypothesis. Its acceptance would open doors to expanded use of optimality and thermodynamic principles to understand and predict preferential flow. It also could lead to new modes of hydraulic characterization of subsurface media with regard to unsaturated flow, which are much needed as the difficulty of measuring hydraulic properties of the unsaturated zone is a major barrier to the advance of hydrologic science. In practical terms, a new guideline may be justified: in unsaturated karst or other materials in which flowing water may enhance flowpaths, preferential transport rates in general may be several times faster than through media without such pore-developmental processes.

  9. Quantitative framework for preferential flow initiation and partitioning

    USGS Publications Warehouse

    Nimmo, John R.

    2016-01-01

    A model for preferential flow in macropores is based on the short-range spatial distribution of soil matrix infiltrability. It uses elementary areas at two different scales. One is the traditional representative elementary area (REA), which includes a sufficient heterogeneity to typify larger areas, as for measuring field-scale infiltrability. The other, called an elementary matrix area (EMA), is smaller, but large enough to represent the local infiltrability of soil matrix material, between macropores. When water is applied to the land surface, each EMA absorbs water up to the rate of its matrix infiltrability. Excess water flows into a macropore, becoming preferential flow. The land surface then can be represented by a mesoscale (EMA-scale) distribution of matrix infiltrabilities. Total preferential flow at a given depth is the sum of contributions from all EMAs. Applying the model, one case study with multi-year field measurements of both preferential and diffuse fluxes at a specific depth was used to obtain parameter values by inverse calculation. The results quantify the preferential–diffuse partition of flow from individual storms that differed in rainfall amount, intensity, antecedent soil water, and other factors. Another case study provided measured values of matrix infiltrability to estimate parameter values for comparison and illustrative predictions. These examples give a self-consistent picture from the combination of parameter values, directions of sensitivities, and magnitudes of differences caused by different variables. One major practical use of this model is to calculate the dependence of preferential flow on climate-related factors, such as varying soil wetness and rainfall intensity.

  10. Attached-growth biological reactor

    SciTech Connect

    O'Brien, D.J.; Heiland, W.K.

    1991-12-16

    An attached growth biological reactor for the growth and harvesting of filamentous fungi has been developed. The reactor contains a rigid cylinder which is partially submerged and rotated in a biological medium containing nutrients for fungal growth and which has been inoculated with a filamentous fungal medium. The filamentous fungi attaches itself to and grows upon the cylinder wherein it is removed by use of a doctoring blade. The reactor can be operated in a continuous mode by continuously supplying oxygen and nutrients to the reactor.

  11. Attachment Processes in Eating Disorder and Depression.

    ERIC Educational Resources Information Center

    Cole-Detke, Holland; Kobak, Roger

    1996-01-01

    Examines the relationship between attachment strategies and symptom reporting among college women (N=61). The Adult Attachment Interview (AAI) was administered and interview transcripts were rated with the Attachment Interview Q-Sort. Findings support the hypothesis that secondary or defensive attachment strategies predispose individuals toward…

  12. Characterizing soil preferential flow using iodine--starch staining experiments and the active region model

    SciTech Connect

    Sheng, Feng; Wang, Kang; Zhang, Renduo; Liu, Hui-Hai

    2009-03-01

    Thirteen iodine-starch staining experiments with different boundary conditions and measurement scales were conducted at two sites to study preferential flow processes in natural unsaturated soils. Digital imaging analyses were implemented to obtain the corresponding preferential flow patterns. The test results are used to evaluate a recently proposed active region model in terms of its usefulness and robustness for characterizing unsaturated flow processes at field scale. Test results provide useful insights into flow patterns in unsaturated soils. They show that flow pattern depends on the top boundary condition. As the total infiltrating-water depth increased form 20 mm to 80 mm for the 100 x 100 cm{sup 2} plots, the corresponding flow pattern changed from few preferential flow paths associated with a relatively small degree of stained coverage and a small infiltration depth, to a pattern characterized by a higher stained coverage and a larger infiltration depth, and to (finally) a relatively homogeneous flow pattern with few unstained area and a much larger infiltration depth. Test results also show that the preferential flow pattern became generally more heterogeneous and complex for a larger measurement scale (or size of infiltration plot). These observations support the general idea behind the active region model that preferential flow pattern in unsaturated soils are dynamic and depend on water flow conditions. Further analyses of the test results indicate that the active-region model is able to capture the major features of the observed flow pattern at the scale of interest, and the determined parameter values do not significantly depend on the test conditions (initial water content and total amount of infiltrating water) for a given test site. This supports the validity of the active region model that considers that parameter to be a property of the corresponding unsaturated soil. Results also show that some intrinsic relation seems to exist between active

  13. Attachment, parenting styles and bullying during pubertal years.

    PubMed

    van der Watt, Ronél

    2014-01-01

    Research that focuses on combining attachment, parenting styles, bullying and the reciprocal nature thereof in the parent-adolescent and peer relationships is limited. The bio-psychosocial changes that adolescents experience open up broader social realities and are perceived differently by parents and adolescents. Attachment processes and parenting styles may elicit dissimilar perceptions. These processes are also associated with the multifaceted dynamics of bullying. The aim of the article is to advocate for research on the possible link between the implications of attachment, parenting styles and bullying. Exploring the association between attachment, parenting styles and bullying can deepen the understanding of the developmental challenges within the parent-adolescent relationship, add insight to the different perceptions of adolescents and parents, and complement intervention programmes accordingly. Firstly, this article outlines bio-psychosocial changes in the pubertal years as related to the social realities of the adolescent. Secondly, a discussion on the concepts 'attachment', 'parenting styles', 'bullying', and the potential link between these concepts will follow. Thirdly, an outline of the clinical implications of the apparent association between these concepts is given. The article concludes with recommendations that researchers can consider while exploring the relationship between attachment, parenting styles, and bullying and the delineation thereof in the parent-adolescent relationship. PMID:25533411

  14. Paddy soil cracks: characteristics and their impact on preferential flow

    NASA Astrophysics Data System (ADS)

    Zhang, Zhongbin; Peng, Xinhua

    2015-04-01

    Paddy soils with harrowing and puddling easily crack under alternate flooding and drying cycles (AFD). These cracks in paddy field may become pathways of preferential flow, improving water infiltration and increasing the pollution risk of groundwater. The objectives of this study were to investigate the 2D and 3D characteristics of soil cracks in paddy fields; and to determine their impacts on preferential flow. Two paddy fields, one cultivated for 20 years (YPF) and the other cultivated for more than 100 years (OPF), were subjected to either alternate flooding and drying (AFD) or continuous flooding (CF) during rice growing season. After the harvest of late rice crop, soil surface cracks were recorded using digital camera; and 3D structure of soil cracks was scanned by computed tomography (CT). The characteristics of 2D and 3D soil cracks were quantified with the aid of image analysis. The influence of soil cracks on preferential flow was characterized by tension infiltrometer, dye tracer and ion breakthrough curve. Our main results in this study were summed up as follows: under AFD condition, for the 2D soil cracks, the YPF presented 10 fold more cracks in quantity but these cracks were finer and more complicated as compared to those generated in the OPF. The results of CT scanning showed that the presence of soil cracks under the AFD increased average macropore length but decreased the number of macropores significantly, and it also changed macropore size distribution and macropore area density distribution with soil depth. The 3D structures of soil cracks were complicated but can be quantified using CT. The depth of soil cracks in young paddy field (7.58 cm) was smaller than that in old paddy field (9.34 cm), but soil cracks in both fields did not reach the plough pan (about 15 cm). Soil cracks significantly increased soil hydraulic conductivity. They serviced as pathways for preferential flow only in plow layer, as evidenced by a large dyed area above plough

  15. Weighted trade network in a model of preferential bipartite transactions

    NASA Astrophysics Data System (ADS)

    Chakraborty, Abhijit; Manna, S. S.

    2010-01-01

    Using a model of wealth distribution where traders are characterized by quenched random saving propensities and trade among themselves by bipartite transactions, we mimic the enhanced rates of trading of the rich by introducing the preferential selection rule using a pair of continuously tunable parameters. The bipartite trading defines a growing trade network of traders linked by their mutual trade relationships. With the preferential selection rule this network appears to be highly heterogeneous characterized by the scale-free nodal degree and the link weight distributions and presents signatures of nontrivial strength-degree correlations. With detailed numerical simulations and using finite-size scaling analysis we present evidence that the associated critical exponents are continuous functions of the tuning parameters. However the wealth distribution has been observed to follow the well-known Pareto law robustly for all positive values of the tuning parameters.

  16. A Pairwise Preferential Interaction Model for Understanding Peptide Aggregation

    PubMed Central

    Kang, Myungshim

    2010-01-01

    A pairwise preferential interaction model (PPIM), based on Kirkwood–Buff integrals, is developed to quantify and characterize the interactions between some of the functional groups commonly observed in peptides. The existing experimental data are analyzed to determine the preferential interaction (PI) parameters for different amino acid and small peptide systems in aqueous solutions. The PIs between the different functional groups present in the peptides are then isolated and quantified by assuming simple pairwise additivity. The PPIM approach provides consistent estimates for the pair interactions between the same functional groups obtained from different solute molecules. Furthermore, these interactions appear to be chemically intuitive. It is argued that this type of approach can provide valuable information concerning specific functional group correlations which could give rise to peptide aggregation. PMID:20694045

  17. Endothelial-dependent vasodilators preferentially increase subendocardial blood flow

    SciTech Connect

    Pelc, L.R.; Gross, G.J.; Warltier, D.C.

    1986-03-05

    Interference with arachidonic acid metabolism on the effect of acetylcholine (Ach) or arachidonic acid (AA) to preferentially increase subendocardial perfusion was investigated in anesthetized dogs. Hemodynamics, regional myocardial blood flow (MBF (ml/min/g):radioactive microspheres) and the left ventricular transmural distribution of flow (endo/epi) were measured. Intracoronary infusion of Ach (10 ..mu..g/min) and AA (585 ..mu..g/min) significantly (P < .05*) increased myocardial perfusion and selectively redistributed flow to the subendocardium (increased endo/epi) without changes in systemic hemodynamics. Inhibition of phospholipase A/sub 2/ by quinacrine (Q; 600 ..mu..g/min, ic) attenuated the increase in myocardial perfusion produced by Ach but not by AA and inhibited the redistribution of flow to the subendocardium. The present results suggest that endothelium-dependent vasodilators produce a preferential increase in subendocardial perfusion via a product of AA metabolism.

  18. Multi-stage, isothermal CO preferential oxidation reactor

    DOEpatents

    Skala, Glenn William; Brundage, Mark A.; Borup, Rodney Lynn; Pettit, William Henry; Stukey, Kevin; Hart-Predmore, David James; Fairchok, Joel

    2000-01-01

    A multi-stage, isothermal, carbon monoxide preferential oxidation (PrOx) reactor comprising a plurality of serially arranged, catalyzed heat exchangers, each separated from the next by a mixing chamber for homogenizing the gases exiting one heat exchanger and entering the next. In a preferred embodiment, at least some of the air used in the PrOx reaction is injected directly into the mixing chamber between the catalyzed heat exchangers.

  19. The Cytoskeleton Regulates Cell Attachment Strength

    PubMed Central

    Fuhrmann, Alexander; Engler, Adam J.

    2015-01-01

    Quantitative information about adhesion strength is a fundamental part of our understanding of cell-extracellular matrix (ECM) interactions. Adhesion assays should measure integrin-ECM bond strength, but reports now suggest that cell components remain behind after exposure to acute force for radial shear assays in the presence of divalent cations that increase integrin-ECM affinity. Here, we show that focal adhesion proteins FAK, paxillin, and vinculin but not the cytoskeletal protein actin remain behind after shear-induced detachment of HT1080 fibrosarcoma cells. Cytoskeletal stabilization increased attachment strength by eightfold, whereas cross-linking integrins to the substrate only caused a 1.5-fold increase. Reducing temperature—only during shear application—also increased attachment strength eightfold, with detachment again occurring between focal adhesion proteins and actin. Detachment at the focal adhesion-cytoskeleton interface was also observed in mouse and human fibroblasts and was ligand-independent, highlighting the ubiquity of this mode of detachment in the presence of divalent cations. These data show that the cytoskeleton and its dynamic coupling to focal adhesions are critically important for cell adhesion in niche with divalent cations. PMID:26153702

  20. [Early attachement relationships and epigenetic customization].

    PubMed

    Rocchi, Giordana; Serio, Valentina; Carluccio, Giuseppe Mattia; Marini, Isabella; Meuti, Valentina; Zaccagni, Michela; Giacchetti, Nicoletta; Aceti, Franca

    2015-01-01

    Recently, new findings in epigenetic science switched the focus from the observation of physiological intragenomic dynamics to the idea of an environmental co-construction of phenotypic expression. In psichodynamic field, objectual relations and attachement theoreticians emphasized the interpersonal dimension of individual development, focusing the attention on the relational matrix of self organization. The construction of stable affective-behavioral traits throughout different parenting styles has actually found a coincidence in ethological studies, which have explored the epigenetic processes underlying the relationship between caregiving and HPA stress responsiveness. An adequate parenting style seems to support affective regulation throughout psychobiological hidden moderators, which would tend to rebalance the physiological systems homeostasis; an unconfident attachment style would promote, on the other hand, the allostatic load rise. Sites of longlife epigenetic susceptibility have also been identified in humans; although associated with risk of maladaptive developing in adverse environmental conditions, they seem to confer protection under favorable conditions. This persisting possibility of reorganization of stable traits throughout lifetime, which seems to be activated by a relevant environmental input, grant to significant relationships, and to therapeutical one as well, an implicit reconditioning potential which could result into the configuration of new stable affective-behavioral styles. PMID:26418595

  1. Studying the Hydrology of Landslides: Pore Water Pressure, Preferential Flow and Feedbacks Between Slope Displacement and Hillslope Hydrology

    NASA Astrophysics Data System (ADS)

    Bogaard, T.; Greco, R.

    2014-12-01

    Hydrology is one of the most important triggering factors for slope destabilization. When a slope becomes unstable, cracks and fissures develop during slope deformation. These discontinuities affect both geotechnical and hydrological conditions of the slope. The crucial role of water flow, and especially the important role of preferential flow in unstable slopes, is generally recognized. However, in hydrological modelling, the unstable slope is characterized using static subsurface properties. The dynamic feedback between slope deformation and slope hydrology, being positive or negative depending on other geotechnical conditions, is not taken into account although it influences the pore pressure distribution and as such the overall stability. This research aims to highlight and quantify the dynamic nature of the subsurface hydrological conditions in unstable slopes. We focus on the role preferential flow has on slope destabilization and more specifically on the feedbacks between differential displacement and hydrological behaviour of the subsurface in natural slopes. We will present examples of field experimental work where we measured the hydrological influence of fissures, theoretical analysis and case study modelling of combined hydrology and slope stability, including feedbacks. The results show the subtle trade-off of increased infiltration and storage capacity in a slope and the increased drainage capacity of well connected preferential flow paths. We will furthermore highlight the current status of our knowledge as well as identify the knowledge gaps we face and the importance of cross- and multidisciplinary approach to better understand the internal dynamics of slope deformation and hillslope hydrology.

  2. Considerations in producing preferentially reduced half-antibody fragments.

    PubMed

    Makaraviciute, Asta; Jackson, Carolyn D; Millner, Paul A; Ramanaviciene, Almira

    2016-02-01

    Half-antibody fragments are a promising reagent for biosensing, drug-delivery and labeling applications, since exposure of the free thiol group in the Fc hinge region allows oriented reaction. Despite the structural variations among the molecules of different IgG subclasses and those obtained from different hosts, only generalized preferential antibody reduction protocols are currently available. Preferential reduction of polyclonal sheep anti-digoxin, rabbit anti-Escherichia coli and anti-myoglobin class IgG antibodies to half-antibody fragments has been investigated. A mild reductant 2-mercaptoethylamine (2-MEA) and a slightly stronger reductant tris(2-carboxyethyl)phosphine (TCEP) were used and the fragments obtained were quantitatively determined by SDS-PAGE analysis. It has been shown that the yields of half-antibody fragments could be increased by lowering the pH of the reduction mixtures. However, antibody susceptibility to the reductants varied. At pH4.5 the highest yield of sheep anti-digoxin IgG half-antibody fragments was obtained with 1M 2-MEA. Conversely, rabbit IgG half-antibody fragments could only be obtained with the stronger reductant TCEP. Preferential reduction of rabbit anti-myoglobin IgG antibodies was optimized and the highest half-antibody yield was obtained with 35 mM TCEP. Finally, it has been demonstrated that produced anti-myoglobin half-IgG fragments retained their binding activity. PMID:26779832

  3. Group preferential selection promotes cooperation in spatial public goods game

    NASA Astrophysics Data System (ADS)

    Zhang, Hong-Bin; Wang, Hong

    2014-04-01

    We study the evolution of cooperation in public goods games on the square lattice, focusing on the co-player learning mechanism based on the preferential selection that are brought about by wealthy information of groups where participants collect and search for potential imitators from those groups. We find that co-player learning mechanism based on the choice of weighted group can lead to the promotion of public cooperation by means of the information of wealthy groups that is obtained by participants, and after that the partial choice of public goods groups is enhanced with the tunable preferential parameter. Our results highlight that the learning interactions is not solely confined to the restricted connection among players, but co-players of wealthy groups have the opportunity to be as a role model in the promotion of cooperative evolution. Moreover, we also find the size of learning affects the choice of distant players, cooperators (defectors) having more paths to exploit the phalanx of opponents to survive when the value of preferential parameter is small. Besides, the extinction thresholds of cooperators and defectors for different values of noise are also investigated.

  4. Vibration analysis of rotor blades with an attached concentrated mass

    NASA Technical Reports Server (NTRS)

    Murthy, V. R.; Barna, P. S.

    1977-01-01

    The effect of an attached concentrated mass on the dynamics of helicopter rotor blades is determined. The point transmission matrix method was used to define, through three completely automated computer programs, the natural vibrational characteristics (natural frequencies and mode shapes) of rotor blades. The problems of coupled flapwise bending, chordwise bending, and torsional vibration of a twisted nonuniform blade and its special subcase pure torsional vibration are discussed. The orthogonality relations that exist between the natural modes of rotor blades with an attached concentrated mass are derived. The effect of pitch, rotation, and point mass parameters on the collective, cyclic, scissor, and pure torsional modes of a seesaw rotor blade is determined.

  5. DMM assessments of attachment and adaptation: Procedures, validity and utility.

    PubMed

    Farnfield, Steve; Hautamäki, Airi; Nørbech, Peder; Sahhar, Nicola

    2010-07-01

    This article gives a brief over view of the Dynamic-Maturational Model of attachment and adaptation (DMM; Crittenden, 2008) together with the various DMM assessments of attachment that have been developed for specific stages of development. Each assessment is discussed in terms of procedure, outcomes, validity, advantages and limitations, comparable procedures and areas for further research and validation. The aims are twofold: to provide an introduction to DMM theory and its application that underlie the articles in this issue of CCPP; and to provide researchers and clinicians with a guide to DMM assessments. PMID:20603420

  6. Beginnings and Endings in Social Work Supervision: The Interaction between Attachment and Developmental Processes

    ERIC Educational Resources Information Center

    Bennett, Susanne; Deal, Kathleen Holtz

    2009-01-01

    This article discusses the interaction of attachment processes and stages of social work student development within the field supervisory relationship and suggests ways supervisors can modify interactions with students. Attachment theory and research provide a framework for understanding innate capacities of students and the relational dynamics of…

  7. Rapid runoff via shallow throughflow and deeper preferential flow in a boreal catchment underlain by frozen silt (Alaska, USA)

    NASA Astrophysics Data System (ADS)

    Koch, J. C.; Ewing, S. A.; Striegl, R.; McKnight, D. M.

    2013-02-01

    In high-latitude catchments where permafrost is present, runoff dynamics are complicated by seasonal active-layer thaw, which may cause a change in the dominant flowpaths as water increasingly contacts mineral soils of low hydraulic conductivity. A 2-year study, conducted in an upland catchment in Alaska (USA) underlain by frozen, well-sorted eolian silt, examined changes in infiltration and runoff with thaw. It was hypothesized that rapid runoff would be maintained by flow through shallow soils during the early summer and deeper preferential flow later in the summer. Seasonal changes in soil moisture, infiltration, and runoff magnitude, location, and chemistry suggest that transport is rapid, even when soils are thawed to their maximum extent. Between June and September, a shift occurred in the location of runoff, consistent with subsurface preferential flow in steep and wet areas. Uranium isotopes suggest that late summer runoff erodes permafrost, indicating that substantial rapid flow may occur along the frozen boundary. Together, throughflow and deep preferential flow may limit upland boreal catchment water and solute storage, and subsequently biogeochemical cycling on seasonal to annual timescales. Deep preferential flow may be important for stream incision, network drainage development, and the release of ancient carbon to ecosystems.

  8. Rapid runoff via shallow throughflow and deeper preferential flow in a boreal catchment underlain by frozen silt (Alaska, USA)

    USGS Publications Warehouse

    Koch, Joshua C.; Ewing, Stephanie A.; Striegl, Rob; McKnight, Diane M.

    2013-01-01

    In high-latitude catchments where permafrost is present, runoff dynamics are complicated by seasonal active-layer thaw, which may cause a change in the dominant flowpaths as water increasingly contacts mineral soils of low hydraulic conductivity. A 2-year study, conducted in an upland catchment in Alaska (USA) underlain by frozen, well-sorted eolian silt, examined changes in infiltration and runoff with thaw. It was hypothesized that rapid runoff would be maintained by flow through shallow soils during the early summer and deeper preferential flow later in the summer. Seasonal changes in soil moisture, infiltration, and runoff magnitude, location, and chemistry suggest that transport is rapid, even when soils are thawed to their maximum extent. Between June and September, a shift occurred in the location of runoff, consistent with subsurface preferential flow in steep and wet areas. Uranium isotopes suggest that late summer runoff erodes permafrost, indicating that substantial rapid flow may occur along the frozen boundary. Together, throughflow and deep preferential flow may limit upland boreal catchment water and solute storage, and subsequently biogeochemical cycling on seasonal to annual timescales. Deep preferential flow may be important for stream incision, network drainage development, and the release of ancient carbon to ecosystems

  9. Thinking of attachments reduces noradrenergic stress response.

    PubMed

    Bryant, Richard A; Chan, Lilian

    2015-10-01

    Although there is much evidence that activating mental representations of attachments figure is beneficial for psychological health and can reduce stress response, no research has directly investigated whether attachment activation can ameliorate hormonal stress response. This study investigated whether activating an attachment figure or a non-attachment figure following administration of a socially evaluated cold pressor test to elicit stress impacted on glucocorticoid and noradrenergic response. Participants (N = 61) provided baseline salivary samples, underwent a cold pressor test, then imagined an attachment or non-attachment figure, and finally provided subsequent saliva samples. Participants who imagined a non-attachment figure had greater noradrenergic response following the stressor than those who imagined an attachment figure. These findings highlight that activating attachment representations can ameliorate the immediate noradrenergic stress response. PMID:26115145

  10. Dissociative electron attachment studies on acetone

    SciTech Connect

    Prabhudesai, Vaibhav S. Tadsare, Vishvesh; Ghosh, Sanat; Gope, Krishnendu; Davis, Daly; Krishnakumar, E.

    2014-10-28

    Dissociative electron attachment (DEA) to acetone is studied in terms of the absolute cross section for various fragment channels in the electron energy range of 0–20 eV. H{sup −} is found to be the most dominant fragment followed by O{sup −} and OH{sup −} with only one resonance peak between 8 and 9 eV. The DEA dynamics is studied by measuring the angular distribution and kinetic energy distribution of fragment anions using Velocity Slice Imaging technique. The kinetic energy and angular distribution of H{sup −} and O{sup −} fragments suggest a many body break-up for the lone resonance observed. The ab initio calculations show that electron is captured in the multi-centered anti-bonding molecular orbital which would lead to a many body break-up of the resonance.