Structural organization of process zones in upland watersheds of central Nevada and its influence on basin connectivity, dynamics, and wet meadow complexes

Treesearch

Jerry R. Miller; Mark L. Lord; Lionel F. Villarroel; Dru Germanoski; Jeanne C. Chambers

2012-01-01

The drainage network within upland watersheds in central Nevada can be subdivided into distinct zones each dominated by a unique set of processes on the basis of valley form, the geological materials that comprise the valley floor, and the presence or absence of surficial channels. On hillslopes, the type and structure (frequency, length, and spatial arrangement) of...

Routing UAVs to Co-Optimize Mission Effectiveness and Network Performance with Dynamic Programming

DTIC Science & Technology

2011-03-01

Heuristics on Hexagonal Connected Dominating Sets to Model Routing Dissemination," in Communication Theory, Reliability, and Quality of Service (CTRQ...24] Matthew Capt. USAF Compton, Improving the Quality of Service and Security of Military Networks with a Network Tasking Order Process, 2010. [25...Wesley, 2006. [32] James Haught, "Adaptive Quality of Service Engine with Dynamic Queue Control," Air Force Institute of Technology, Wright

Optimal operation management of fuel cell/wind/photovoltaic power sources connected to distribution networks

NASA Astrophysics Data System (ADS)

Niknam, Taher; Kavousifard, Abdollah; Tabatabaei, Sajad; Aghaei, Jamshid

2011-10-01

In this paper a new multiobjective modified honey bee mating optimization (MHBMO) algorithm is presented to investigate the distribution feeder reconfiguration (DFR) problem considering renewable energy sources (RESs) (photovoltaics, fuel cell and wind energy) connected to the distribution network. The objective functions of the problem to be minimized are the electrical active power losses, the voltage deviations, the total electrical energy costs and the total emissions of RESs and substations. During the optimization process, the proposed algorithm finds a set of non-dominated (Pareto) optimal solutions which are stored in an external memory called repository. Since the objective functions investigated are not the same, a fuzzy clustering algorithm is utilized to handle the size of the repository in the specified limits. Moreover, a fuzzy-based decision maker is adopted to select the 'best' compromised solution among the non-dominated optimal solutions of multiobjective optimization problem. In order to see the feasibility and effectiveness of the proposed algorithm, two standard distribution test systems are used as case studies.

Scale and processes dominating soil erosion and sediment transport: case studies from Indonesia and Australia

NASA Astrophysics Data System (ADS)

van Dijk, A. I. J. M.; Bruijnzeel, L. A.

2009-04-01

Soil erosion and sediment transport at different scales of space and time are dominated by a variable set of landscape properties and processes. Research results from West Java (Indonesia) and southeast Australia are presented, taking a natural resources management perspective. The dominant role of vegetation and soil health, rainfall infiltration, and connectivity between hillslope and stream are elaborated on. In humid volcanic upland West Java, vegetative cover and associated infiltration capacity are the dominant control on surface runoff and sediment generation, with additional variation attributed to slope and soil surface structure. Use of process models to replicate and upscale field measurements highlighted that a predictive theory to link vegetative cover and infiltration capacity is lacking, and that full knowledge of the covariance between terrain attributes that promote sediment generation is needed for process based modelling. At the hillslope to catchment scale, slope gradient and a less erodible substrate became additional constraints on sediment yield. A conceptual framework relating processes, scale and sediment delivery ratio was developed. In water-limited southeast Australia, measures to reduce erosion and sediment production generally aim to intercept surface runoff, allowing runoff to infiltrate and sediment to settle on vegetated buffer strips or roadsides or in leaky dams. It is illustrated how remote sensing can help to assess the sources of sediment and hydrological connectivity at different scales and to identify opportunities for mitigation.

Low-angle faulting in strike-slip dominated settings: Seismic evidence from the Maritimes Basin, Canada

NASA Astrophysics Data System (ADS)

Pinet, Nicolas; Dietrich, Jim; Duchesne, Mathieu J.; Hinds, Steve J.; Brake, Virginia

2018-07-01

The Maritimes Basin is an upper Paleozoic sedimentary basin centered in the Gulf of St. Lawrence (Canada). Early phases of basin formation included the development of partly connected sub-basins bounded by high-angle faults, in an overall strike-slip setting. Interpretation of reprocessed seismic reflection data indicates that a low-angle detachment contributed to the formation of a highly asymmetric sub-basin. This detachment was rotated toward a lower angle and succeeded by high-angle faults that sole into the detachment or cut it. This model bears similarities to other highly extended terranes and appears to be applicable to strike-slip and/or transtensional settings.

Identification of a core-periphery structure among participants of a business climate survey. An investigation based on the ZEW survey data

NASA Astrophysics Data System (ADS)

Stolzenburg, U.; Lux, T.

2011-12-01

Processes of social opinion formation might be dominated by a set of closely connected agents who constitute the cohesive `core' of a network and have a higher influence on the overall outcome of the process than those agents in the more sparsely connected `periphery'. Here we explore whether such a perspective could shed light on the dynamics of a well known economic sentiment index. To this end, we hypothesize that the respondents of the survey under investigation form a core-periphery network, and we identify those agents that define the core (in a discrete setting) or the proximity of each agent to the core (in a continuous setting). As it turns out, there is significant correlation between the so identified cores of different survey questions. Both the discrete and the continuous cores allow an almost perfect replication of the original series with a reduced data set of core members or weighted entries according to core proximity. Using a monthly time series on industrial production in Germany, we also compared experts' predictions with the real economic development. The core members identified in the discrete setting showed significantly better prediction capabilities than those agents assigned to the periphery of the network.

Functional brain networks related to individual differences in human intelligence at rest.

PubMed

Hearne, Luke J; Mattingley, Jason B; Cocchi, Luca

2016-08-26

Intelligence is a fundamental ability that sets humans apart from other animal species. Despite its importance in defining human behaviour, the neural networks responsible for intelligence are not well understood. The dominant view from neuroimaging work suggests that intelligent performance on a range of tasks is underpinned by segregated interactions in a fronto-parietal network of brain regions. Here we asked whether fronto-parietal interactions associated with intelligence are ubiquitous, or emerge from more widespread associations in a task-free context. First we undertook an exploratory mapping of the existing literature on functional connectivity associated with intelligence. Next, to empirically test hypotheses derived from the exploratory mapping, we performed network analyses in a cohort of 317 unrelated participants from the Human Connectome Project. Our results revealed a novel contribution of across-network interactions between default-mode and fronto-parietal networks to individual differences in intelligence at rest. Specifically, we found that greater connectivity in the resting state was associated with higher intelligence scores. Our findings highlight the need to broaden the dominant fronto-parietal conceptualisation of intelligence to encompass more complex and context-specific network dynamics.

Left frontal hub connectivity delays cognitive impairment in autosomal-dominant and sporadic Alzheimer's disease.

PubMed

Franzmeier, Nicolai; Düzel, Emrah; Jessen, Frank; Buerger, Katharina; Levin, Johannes; Duering, Marco; Dichgans, Martin; Haass, Christian; Suárez-Calvet, Marc; Fagan, Anne M; Paumier, Katrina; Benzinger, Tammie; Masters, Colin L; Morris, John C; Perneczky, Robert; Janowitz, Daniel; Catak, Cihan; Wolfsgruber, Steffen; Wagner, Michael; Teipel, Stefan; Kilimann, Ingo; Ramirez, Alfredo; Rossor, Martin; Jucker, Mathias; Chhatwal, Jasmeer; Spottke, Annika; Boecker, Henning; Brosseron, Frederic; Falkai, Peter; Fliessbach, Klaus; Heneka, Michael T; Laske, Christoph; Nestor, Peter; Peters, Oliver; Fuentes, Manuel; Menne, Felix; Priller, Josef; Spruth, Eike J; Franke, Christiana; Schneider, Anja; Kofler, Barbara; Westerteicher, Christine; Speck, Oliver; Wiltfang, Jens; Bartels, Claudia; Araque Caballero, Miguel Ángel; Metzger, Coraline; Bittner, Daniel; Weiner, Michael; Lee, Jae-Hong; Salloway, Stephen; Danek, Adrian; Goate, Alison; Schofield, Peter R; Bateman, Randall J; Ewers, Michael

2018-04-01

Patients with Alzheimer's disease vary in their ability to sustain cognitive abilities in the presence of brain pathology. A major open question is which brain mechanisms may support higher reserve capacity, i.e. relatively high cognitive performance at a given level of Alzheimer's pathology. Higher functional MRI-assessed functional connectivity of a hub in the left frontal cortex is a core candidate brain mechanism underlying reserve as it is associated with education (i.e. a protective factor often associated with higher reserve) and attenuated cognitive impairment in prodromal Alzheimer's disease. However, no study has yet assessed whether such hub connectivity of the left frontal cortex supports reserve throughout the evolution of pathological brain changes in Alzheimer's disease, including the presymptomatic stage when cognitive decline is subtle. To address this research gap, we obtained cross-sectional resting state functional MRI in 74 participants with autosomal dominant Alzheimer's disease, 55 controls from the Dominantly Inherited Alzheimer's Network and 75 amyloid-positive elderly participants, as well as 41 amyloid-negative cognitively normal elderly subjects from the German Center of Neurodegenerative Diseases multicentre study on biomarkers in sporadic Alzheimer's disease. For each participant, global left frontal cortex connectivity was computed as the average resting state functional connectivity between the left frontal cortex (seed) and each voxel in the grey matter. As a marker of disease stage, we applied estimated years from symptom onset in autosomal dominantly inherited Alzheimer's disease and cerebrospinal fluid tau levels in sporadic Alzheimer's disease cases. In both autosomal dominant and sporadic Alzheimer's disease patients, higher levels of left frontal cortex connectivity were correlated with greater education. For autosomal dominant Alzheimer's disease, a significant left frontal cortex connectivity × estimated years of onset interaction was found, indicating slower decline of memory and global cognition at higher levels of connectivity. Similarly, in sporadic amyloid-positive elderly subjects, the effect of tau on cognition was attenuated at higher levels of left frontal cortex connectivity. Polynomial regression analysis showed that the trajectory of cognitive decline was shifted towards a later stage of Alzheimer's disease in patients with higher levels of left frontal cortex connectivity. Together, our findings suggest that higher resilience against the development of cognitive impairment throughout the early stages of Alzheimer's disease is at least partially attributable to higher left frontal cortex-hub connectivity.

On Estimating End-to-End Network Path Properties

NASA Technical Reports Server (NTRS)

Allman, Mark; Paxson, Vern

1999-01-01

The more information about current network conditions available to a transport protocol, the more efficiently it can use the network to transfer its data. In networks such as the Internet, the transport protocol must often form its own estimates of network properties based on measurements per-formed by the connection endpoints. We consider two basic transport estimation problems: determining the setting of the retransmission timer (RTO) for are reliable protocol, and estimating the bandwidth available to a connection as it begins. We look at both of these problems in the context of TCP, using a large TCP measurement set [Pax97b] for trace-driven simulations. For RTO estimation, we evaluate a number of different algorithms, finding that the performance of the estimators is dominated by their minimum values, and to a lesser extent, the timer granularity, while being virtually unaffected by how often round-trip time measurements are made or the settings of the parameters in the exponentially-weighted moving average estimators commonly used. For bandwidth estimation, we explore techniques previously sketched in the literature [Hoe96, AD98] and find that in practice they perform less well than anticipated. We then develop a receiver-side algorithm that performs significantly better.

Salient Multiculturalism Enhances Minority Group Members' Feelings of Power.

PubMed

Vorauer, Jacquie D; Quesnel, Matthew S

2017-02-01

The present research examined how messages advocating different intergroup ideologies affect outcomes relevant to minority group members' ability to exert power in exchanges with dominant group members. We expected that salient multiculturalism would have positive implications for minority group members' feelings of power by virtue of highlighting essential contributions they make to society, and that no such empowering effect would be evident for them in connection with alternative ideologies such as color-blindness or for dominant group members. Results across four studies involving different participant populations, operationalizations of ideology, ethnic minority groups, and experimental settings were consistent with these hypotheses and further indicated that the effects of salient multiculturalism on feelings of power had downstream implications for expectations of control in an ostensibly upcoming intergroup interaction and general goal-directed cognition.

Left frontal hub connectivity delays cognitive impairment in autosomal-dominant and sporadic Alzheimer’s disease

PubMed Central

Franzmeier, Nicolai; Düzel, Emrah; Jessen, Frank; Buerger, Katharina; Levin, Johannes; Duering, Marco; Dichgans, Martin; Haass, Christian; Suárez-Calvet, Marc; Fagan, Anne M; Paumier, Katrina; Benzinger, Tammie; Masters, Colin L; Morris, John C; Perneczky, Robert; Janowitz, Daniel; Catak, Cihan; Wolfsgruber, Steffen; Wagner, Michael; Teipel, Stefan; Kilimann, Ingo; Ramirez, Alfredo; Rossor, Martin; Jucker, Mathias; Chhatwal, Jasmeer; Spottke, Annika; Boecker, Henning; Brosseron, Frederic; Falkai, Peter; Fliessbach, Klaus; Heneka, Michael T; Laske, Christoph; Nestor, Peter; Peters, Oliver; Fuentes, Manuel; Menne, Felix; Priller, Josef; Spruth, Eike J; Franke, Christiana; Schneider, Anja; Kofler, Barbara; Westerteicher, Christine; Speck, Oliver; Wiltfang, Jens; Bartels, Claudia; Araque Caballero, Miguel Ángel; Metzger, Coraline; Bittner, Daniel; Weiner, Michael; Lee, Jae-Hong; Salloway, Stephen; Danek, Adrian; Goate, Alison; Schofield, Peter R; Bateman, Randall J; Ewers, Michael

2018-01-01

Abstract Patients with Alzheimer’s disease vary in their ability to sustain cognitive abilities in the presence of brain pathology. A major open question is which brain mechanisms may support higher reserve capacity, i.e. relatively high cognitive performance at a given level of Alzheimer’s pathology. Higher functional MRI-assessed functional connectivity of a hub in the left frontal cortex is a core candidate brain mechanism underlying reserve as it is associated with education (i.e. a protective factor often associated with higher reserve) and attenuated cognitive impairment in prodromal Alzheimer’s disease. However, no study has yet assessed whether such hub connectivity of the left frontal cortex supports reserve throughout the evolution of pathological brain changes in Alzheimer’s disease, including the presymptomatic stage when cognitive decline is subtle. To address this research gap, we obtained cross-sectional resting state functional MRI in 74 participants with autosomal dominant Alzheimer’s disease, 55 controls from the Dominantly Inherited Alzheimer’s Network and 75 amyloid-positive elderly participants, as well as 41 amyloid-negative cognitively normal elderly subjects from the German Center of Neurodegenerative Diseases multicentre study on biomarkers in sporadic Alzheimer’s disease. For each participant, global left frontal cortex connectivity was computed as the average resting state functional connectivity between the left frontal cortex (seed) and each voxel in the grey matter. As a marker of disease stage, we applied estimated years from symptom onset in autosomal dominantly inherited Alzheimer’s disease and cerebrospinal fluid tau levels in sporadic Alzheimer’s disease cases. In both autosomal dominant and sporadic Alzheimer’s disease patients, higher levels of left frontal cortex connectivity were correlated with greater education. For autosomal dominant Alzheimer’s disease, a significant left frontal cortex connectivity × estimated years of onset interaction was found, indicating slower decline of memory and global cognition at higher levels of connectivity. Similarly, in sporadic amyloid-positive elderly subjects, the effect of tau on cognition was attenuated at higher levels of left frontal cortex connectivity. Polynomial regression analysis showed that the trajectory of cognitive decline was shifted towards a later stage of Alzheimer’s disease in patients with higher levels of left frontal cortex connectivity. Together, our findings suggest that higher resilience against the development of cognitive impairment throughout the early stages of Alzheimer’s disease is at least partially attributable to higher left frontal cortex-hub connectivity. PMID:29462334

Causal-explanatory pluralism: How intentions, functions, and mechanisms influence causal ascriptions.

PubMed

Lombrozo, Tania

2010-12-01

Both philosophers and psychologists have argued for the existence of distinct kinds of explanations, including teleological explanations that cite functions or goals, and mechanistic explanations that cite causal mechanisms. Theories of causation, in contrast, have generally been unitary, with dominant theories focusing either on counterfactual dependence or on physical connections. This paper argues that both approaches to causation are psychologically real, with different modes of explanation promoting judgments more or less consistent with each approach. Two sets of experiments isolate the contributions of counterfactual dependence and physical connections in causal ascriptions involving events with people, artifacts, or biological traits, and manipulate whether the events are construed teleologically or mechanistically. The findings suggest that when events are construed teleologically, causal ascriptions are sensitive to counterfactual dependence and relatively insensitive to the presence of physical connections, but when events are construed mechanistically, causal ascriptions are sensitive to both counterfactual dependence and physical connections. The conclusion introduces an account of causation, an "exportable dependence theory," that provides a way to understand the contributions of physical connections and teleology in terms of the functions of causal ascriptions. Copyright © 2010 Elsevier Inc. All rights reserved.

Functional brain networks related to individual differences in human intelligence at rest

PubMed Central

Hearne, Luke J.; Mattingley, Jason B.; Cocchi, Luca

2016-01-01

Intelligence is a fundamental ability that sets humans apart from other animal species. Despite its importance in defining human behaviour, the neural networks responsible for intelligence are not well understood. The dominant view from neuroimaging work suggests that intelligent performance on a range of tasks is underpinned by segregated interactions in a fronto-parietal network of brain regions. Here we asked whether fronto-parietal interactions associated with intelligence are ubiquitous, or emerge from more widespread associations in a task-free context. First we undertook an exploratory mapping of the existing literature on functional connectivity associated with intelligence. Next, to empirically test hypotheses derived from the exploratory mapping, we performed network analyses in a cohort of 317 unrelated participants from the Human Connectome Project. Our results revealed a novel contribution of across-network interactions between default-mode and fronto-parietal networks to individual differences in intelligence at rest. Specifically, we found that greater connectivity in the resting state was associated with higher intelligence scores. Our findings highlight the need to broaden the dominant fronto-parietal conceptualisation of intelligence to encompass more complex and context-specific network dynamics. PMID:27561736

"This is my way": reimagining disability, in/dependence and interconnectedness of persons and assistive technologies.

PubMed

Gibson, Barbara E; Carnevale, Franco A; King, Gillian

2012-01-01

Postmodernism provides a radical alternative to the dominant discourses of Western societies that emphasize autonomy and independence. It suggests a reimagining of the relationship between the self and the body and the increasingly blurred boundaries between biology and machine. The purpose of this article is to explore in/dependence through a discussion of interconnectedness of persons and assistive technologies. Drawing on postmodern theories, we discuss the interconnections inherent in disability experiences through the case example of Mimi, an adolescent girl with severe physical disabilities. We consider how Mimi, her assistive technologies and her parents can be viewed as assemblages of bodies/technologies/subjectivities that together achieve a set of practices. An examination of these various couplings suggests different understandings of disability that open up possibilities for multiple connections and reimagines dependencies as connectivities. Connectivity can be embraced to explore multiple ways of being-in-the-world for all persons and problematizes the goals of independence inherent in rehabilitation practices.

Rainbow tensor model with enhanced symmetry and extreme melonic dominance

NASA Astrophysics Data System (ADS)

Itoyama, H.; Mironov, A.; Morozov, A.

2017-08-01

We introduce and briefly analyze the rainbow tensor model where all planar diagrams are melonic. This leads to considerable simplification of the large N limit as compared to that of the matrix model: in particular, what are dressed in this limit are propagators only, which leads to an oversimplified closed set of Schwinger-Dyson equations for multi-point correlators. We briefly touch upon the Ward identities, the substitute of the spectral curve and the AMM/EO topological recursion and their possible connections to Connes-Kreimer theory and forest formulas.

THE INTERNAL STRUCTURE OF OVERPRESSURED, MAGNETIZED, RELATIVISTIC JETS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Martí, J. M.; Perucho, M.; Gómez, J. L.

This work presents the first characterization of the internal structure of overpressured, steady superfast-magnetosonic relativistic jets in connection with their dominant type of energy. To this aim, relativistic magnetohydrodynamic simulations of different jet models threaded by a helical magnetic field have been analyzed covering a wide region in the magnetosonic Mach number–specific internal energy plane. The merit of this plane is that models dominated by different types of energy (internal energy: hot jets; rest-mass energy: kinetically dominated jets; magnetic energy: Poynting-flux-dominated jets) occupy well-separated regions. The analyzed models also cover a wide range of magnetizations. Models dominated by the internalmore » energy (i.e., hot models, or Poynting-flux-dominated jets with magnetizations larger than but close to one) have a rich internal structure characterized by a series of recollimation shocks and present the largest variations in the flow Lorentz factor (and internal energy density). Conversely, in kinetically dominated models, there is not much internal or magnetic energy to be converted into kinetic, and the jets are featureless with small variations in the flow Lorentz factor. The presence of a significant toroidal magnetic field threading the jet produces large gradients in the transversal profile of the internal energy density. Poynting-flux-dominated models with high magnetization (≈10 or larger) are prone to be unstable against magnetic pinch modes, which sets limits on the expected magnetization in parsec-scale active galactic nucleus jets or constrains their magnetic field configuration.« less

Emergence of dominant initiation sites for interictal spikes in rat neocortex

PubMed Central

Vitantonio, Daniel; Xu, Weifeng; Geng, Xinling; Wolff, Brian S.; Takagaki, Kentaroh; Motamedi, Gholam K.

2015-01-01

Neuronal populations with unbalanced inhibition can generate interictal spikes (ISs), where each IS starts from a small initiation site and then spreads activation across a larger area. We used in vivo voltage-sensitive dye imaging to map the initiation site of ISs in rat visual cortex disinhibited by epidural application of bicuculline methiodide. Immediately after the application of bicuculline, the IS initiation sites were widely distributed over the entire disinhibited area. After ∼10 min, a small number of sites became “dominant” and initiated the majority of the ISs throughout the course of imaging. Such domination also occurred in cortical slices, which lack long-range connections between the cortex and subcortical structures. This domination of IS initiation sites may allow timing-related plasticity mechanisms to provide a spatial organization where connections projecting outward from the dominant initiation site become strengthened. Understanding the spatiotemporal organization of IS initiation sites may contribute to our understanding of epileptogenesis in its very early stages, because a dominant IS initiation site with strengthened outward connectivity may ultimately develop into a seizure focus. PMID:26445866

An Autonomous Connectivity Restoration Algorithm Based on Finite State Machine for Wireless Sensor-Actor Networks.

PubMed

Zhang, Ying; Wang, Jun; Hao, Guan

2018-01-08

With the development of autonomous unmanned intelligent systems, such as the unmanned boats, unmanned planes and autonomous underwater vehicles, studies on Wireless Sensor-Actor Networks (WSANs) have attracted more attention. Network connectivity algorithms play an important role in data exchange, collaborative detection and information fusion. Due to the harsh application environment, abnormal nodes often appear, and the network connectivity will be prone to be lost. Network self-healing mechanisms have become critical for these systems. In order to decrease the movement overhead of the sensor-actor nodes, an autonomous connectivity restoration algorithm based on finite state machine is proposed. The idea is to identify whether a node is a critical node by using a finite state machine, and update the connected dominating set in a timely way. If an abnormal node is a critical node, the nearest non-critical node will be relocated to replace the abnormal node. In the case of multiple node abnormality, a regional network restoration algorithm is introduced. It is designed to reduce the overhead of node movements while restoration happens. Simulation results indicate the proposed algorithm has better performance on the total moving distance and the number of total relocated nodes compared with some other representative restoration algorithms.

An Autonomous Connectivity Restoration Algorithm Based on Finite State Machine for Wireless Sensor-Actor Networks

PubMed Central

Zhang, Ying; Wang, Jun; Hao, Guan

2018-01-01

With the development of autonomous unmanned intelligent systems, such as the unmanned boats, unmanned planes and autonomous underwater vehicles, studies on Wireless Sensor-Actor Networks (WSANs) have attracted more attention. Network connectivity algorithms play an important role in data exchange, collaborative detection and information fusion. Due to the harsh application environment, abnormal nodes often appear, and the network connectivity will be prone to be lost. Network self-healing mechanisms have become critical for these systems. In order to decrease the movement overhead of the sensor-actor nodes, an autonomous connectivity restoration algorithm based on finite state machine is proposed. The idea is to identify whether a node is a critical node by using a finite state machine, and update the connected dominating set in a timely way. If an abnormal node is a critical node, the nearest non-critical node will be relocated to replace the abnormal node. In the case of multiple node abnormality, a regional network restoration algorithm is introduced. It is designed to reduce the overhead of node movements while restoration happens. Simulation results indicate the proposed algorithm has better performance on the total moving distance and the number of total relocated nodes compared with some other representative restoration algorithms. PMID:29316702

Non-Abelian dark forces and the relic densities of dark glueballs

NASA Astrophysics Data System (ADS)

Forestell, Lindsay; Morrissey, David E.; Sigurdson, Kris

2017-01-01

Our understanding of the Universe is known to be incomplete, and new gauge forces beyond those of the Standard Model might be crucial to describing its observed properties. A minimal and well-motivated possibility is a pure Yang-Mills non-Abelian dark gauge force with no direct connection to the Standard Model. We determine here the relic abundances of the glueball bound states that arise in such theories and investigate their cosmological effects. Glueballs are first formed in a confining phase transition, and their relic densities are set by a network of annihilation and transfer reactions. The lightest glueball has no lighter states to annihilate into, and its yield is set mainly by 3 →2 number-changing processes which persistently release energy into the glueball gas during freeze-out. The abundances of the heavier glueballs are dominated by 2 →2 transfer reactions and tend to be much smaller than the lightest state. We also investigate potential connectors between the dark force and the Standard Model that allow some or all of the dark glueballs to decay. If the connection is weak, the lightest glueball can be very long-lived or stable and is a viable dark matter candidate. For stronger connections, the lightest glueball will decay quickly, but other heavier glueball states can remain stable and contribute to the dark matter density.

Optimizing Synchronization Stability of the Kuramoto Model in Complex Networks and Power Grids

NASA Astrophysics Data System (ADS)

Li, Bo; Wong, K. Y. Michael

Maintaining the stability of synchronization state is crucial for the functioning of many natural and artificial systems. For the Kuramoto model on general weighted networks, the synchronization stability, measured by the dominant Lyapunov exponent at the steady state, is shown to have intricate and nonlinear dependence on the network topology and the dynamical parameters. Specifically, the dominant Lyapunov exponent corresponds to the algebraic connectivity of a meta-graph whose edge weight depends nonlinearly on the steady states. In this study, we utilize the cut-set space (DC) approximation to estimate the nonlinear steady state and simplify the calculation of the stability measure, based on which we further derive efficient algorithms to optimize the synchronization stability. The properties of the optimized networks and application in power grid stability are also discussed. This work is supported by a Grant from the Research Grant Council of Hong Kong (Grant Numbers 605813 and 16322616).

Finite element computation on nearest neighbor connected machines

NASA Technical Reports Server (NTRS)

Mcaulay, A. D.

1984-01-01

Research aimed at faster, more cost effective parallel machines and algorithms for improving designer productivity with finite element computations is discussed. A set of 8 boards, containing 4 nearest neighbor connected arrays of commercially available floating point chips and substantial memory, are inserted into a commercially available machine. One-tenth Mflop (64 bit operation) processors provide an 89% efficiency when solving the equations arising in a finite element problem for a single variable regular grid of size 40 by 40 by 40. This is approximately 15 to 20 times faster than a much more expensive machine such as a VAX 11/780 used in double precision. The efficiency falls off as faster or more processors are envisaged because communication times become dominant. A novel successive overrelaxation algorithm which uses cyclic reduction in order to permit data transfer and computation to overlap in time is proposed.

Collaboration patterns in the German political science co-authorship network.

PubMed

Leifeld, Philip; Wankmüller, Sandra; Berger, Valentin T Z; Ingold, Karin; Steiner, Christiane

2017-01-01

Research on social processes in the production of scientific output suggests that the collective research agenda of a discipline is influenced by its structural features, such as "invisible colleges" or "groups of collaborators" as well as academic "stars" that are embedded in, or connect, these research groups. Based on an encompassing dataset that takes into account multiple publication types including journals and chapters in edited volumes, we analyze the complete co-authorship network of all 1,339 researchers in German political science. Through the use of consensus graph clustering techniques and descriptive centrality measures, we identify the ten largest research clusters, their research topics, and the most central researchers who act as bridges and connect these clusters. We also aggregate the findings at the level of research organizations and consider the inter-university co-authorship network. The findings indicate that German political science is structured by multiple overlapping research clusters with a dominance of the subfields of international relations, comparative politics and political sociology. A small set of well-connected universities takes leading roles in these informal research groups.

Collaboration patterns in the German political science co-authorship network

PubMed Central

Wankmüller, Sandra; Berger, Valentin T. Z.; Ingold, Karin; Steiner, Christiane

2017-01-01

Research on social processes in the production of scientific output suggests that the collective research agenda of a discipline is influenced by its structural features, such as “invisible colleges” or “groups of collaborators” as well as academic “stars” that are embedded in, or connect, these research groups. Based on an encompassing dataset that takes into account multiple publication types including journals and chapters in edited volumes, we analyze the complete co-authorship network of all 1,339 researchers in German political science. Through the use of consensus graph clustering techniques and descriptive centrality measures, we identify the ten largest research clusters, their research topics, and the most central researchers who act as bridges and connect these clusters. We also aggregate the findings at the level of research organizations and consider the inter-university co-authorship network. The findings indicate that German political science is structured by multiple overlapping research clusters with a dominance of the subfields of international relations, comparative politics and political sociology. A small set of well-connected universities takes leading roles in these informal research groups. PMID:28388621

Rumor diffusion model with spatio-temporal diffusion and uncertainty of behavior decision in complex social networks

NASA Astrophysics Data System (ADS)

Zhu, Liang; Wang, Youguo

2018-07-01

In this paper, a rumor diffusion model with uncertainty of human behavior under spatio-temporal diffusion framework is established. Take physical significance of spatial diffusion into account, a diffusion threshold is set under which the rumor is not a trend topic and only spreads along determined physical connections. Heterogeneity of degree distribution and distance distribution has also been considered in theoretical model at the same time. The global existence and uniqueness of classical solution are proved with a Lyapunov function and an approximate classical solution in form of infinite series is constructed with a system of eigenfunction. Simulations and numerical solutions both on Watts-Strogatz (WS) network and Barabási-Albert (BA) network display the variation of density of infected connections from spatial and temporal dimensions. Relevant results show that the density of infected connections is dominated by network topology and uncertainty of human behavior at threshold time. With increase of social capability, rumor diffuses to the steady state in a higher speed. And the variation trends of diffusion size with uncertainty are diverse on different artificial networks.

Rapid Diversity Loss of Competing Animal Species in Well-Connected Landscapes

PubMed Central

Schippers, Peter; Hemerik, Lia; Baveco, Johannes M.; Verboom, Jana

2015-01-01

Population viability of a single species, when evaluated with metapopulation based landscape evaluation tools, always increases when the connectivity of the landscape increases. However, when interactions between species are taken into account, results can differ. We explore this issue using a stochastic spatially explicit meta-community model with 21 competing species in five different competitive settings: (1) weak, coexisting competition, (2) neutral competition, (3) strong, excluding competition, (4) hierarchical competition and (5) random species competition. The species compete in randomly generated landscapes with various fragmentation levels. With this model we study species loss over time. Simulation results show that overall diversity, the species richness in the entire landscape, decreases slowly in fragmented landscapes whereas in well-connected landscapes rapid species losses occur. These results are robust with respect to changing competitive settings, species parameters and spatial configurations. They indicate that optimal landscape configuration for species conservation differs between metapopulation approaches, modelling species separately and meta-community approaches allowing species interactions. The mechanism behind this is that species in well-connected landscapes rapidly outcompete each other. Species that become abundant, by chance or by their completive strength, send out large amounts of dispersers that colonize and take over other patches that are occupied by species that are less abundant. This mechanism causes rapid species loss. In fragmented landscapes the colonization rate is lower, and it is difficult for a new species to establish in an already occupied patch. So, here dominant species cannot easily take over patches occupied by other species and higher diversity is maintained for a longer time. These results suggest that fragmented landscapes have benefits for species conservation previously unrecognized by the landscape ecology and policy community. When species interactions are important, landscapes with a low fragmentation level can be better for species conservation than well-connected landscapes. Moreover, our results indicate that metapopulation based landscape evaluation tools may overestimate the value of connectivity and should be replaced by more realistic meta-community based tools. PMID:26218682

Resting-state functional connectivity predicts the strength of hemispheric lateralization for language processing in temporal lobe epilepsy and normals

PubMed Central

Doucet, Gaëlle E.; Pustina, Dorian; Skidmore, Christopher; Sharan, Ashwini; Sperling, Michael R.; Tracy, Joseph I.

2015-01-01

In temporal lobe epilepsy (TLE), determining the hemispheric specialization for language before surgery is critical to preserving a patient's cognitive abilities post-surgery. To date, the major techniques utilized are limited by the capacity of patients to efficiently realize the task. We determined whether resting-state functional connectivity (rsFC) is a reliable predictor of language hemispheric dominance in right and left TLE patients, relative to controls. We chose three subregions of the inferior frontal cortex (pars orbitalis, pars triangularis and pars opercularis) as the seed regions. All participants performed both a verb generation task and a resting-state fMRI procedure. Based on the language task, we computed a laterality index (LI) for the resulting network. This revealed that 96% of the participants were left-hemisphere dominant, although there remained a large degree of variability in the strength of left lateralization. We tested whether LI correlated with rsFC values emerging from each seed. We revealed a set of regions that was specific to each group. Unique correlations involving the epileptic mesial temporal lobe were revealed for the right and left TLE patients, but not for the controls. Importantly, for both TLE groups, the rsFC emerging from a contralateral seed was the most predictive of LI. Overall, our data depict the broad patterns of rsFC that support strong versus weak left hemisphere language laterality. This project provides the first evidence that rsFC data may potentially be used on its own to verify the strength of hemispheric dominance for language in impaired or pathologic populations. PMID:25187327

Growth dominates choice in network percolation

NASA Astrophysics Data System (ADS)

Vijayaraghavan, Vikram S.; Noël, Pierre-André; Waagen, Alex; D'Souza, Raissa M.

2013-09-01

The onset of large-scale connectivity in a network (i.e., percolation) often has a major impact on the function of the system. Traditionally, graph percolation is analyzed by adding edges to a fixed set of initially isolated nodes. Several years ago, it was shown that adding nodes as well as edges to the graph can yield an infinite order transition, which is much smoother than the traditional second-order transition. More recently, it was shown that adding edges via a competitive process to a fixed set of initially isolated nodes can lead to a delayed, extremely abrupt percolation transition with a significant jump in large but finite systems. Here we analyze a process that combines both node arrival and edge competition. If started from a small collection of seed nodes, we show that the impact of node arrival dominates: although we can significantly delay percolation, the transition is of infinite order. Thus, node arrival can mitigate the trade-off between delay and abruptness that is characteristic of explosive percolation transitions. This realization may inspire new design rules where network growth can temper the effects of delay, creating opportunities for network intervention and control.

Intra-hemispheric intrinsic connectivity asymmetry and its relationships with handedness and language Lateralization.

PubMed

Joliot, M; Tzourio-Mazoyer, N; Mazoyer, B

2016-12-01

Asymmetry in intra-hemispheric intrinsic connectivity, and its association with handedness and hemispheric dominance for language, were investigated in a sample of 290 healthy volunteers enriched in left-handers (52.7%). From the resting-state FMRI data of each participant, we derived an intra-hemispheric intrinsic connectivity asymmetry (HICA) matrix as the difference between the left and right intra-hemispheric matrices of intrinsic correlation computed for each pair of the AICHA atlas ROIs. We defined a similarity measure between the HICA matrices of two individuals as the correlation coefficient of their corresponding elements, and computed for each individual an index of intra-hemispheric intrinsic connectivity asymmetry as the average similarity measure of his HICA matrix to those of the other subjects of the sample (HICAs). Gaussian-mixture modeling of the age-corrected HICAs sample distribution revealed that two types of HICA patterns were present, one (Typical_HICA) including 92.4% of the participants while the other (Atypical_HICA) included only 7.6% of them, mostly left-handers. In addition, we investigated the relationship between asymmetry in intra-hemispheric intrinsic connectivity and language hemispheric dominance, including a potential effect of handedness on this relationship, thanks to an FMRI acquisition during language production from which an hemispheric functional lateralization index for language (HFLI) and a type of hemispheric dominance for language, namely leftward, ambilateral, or rightward, were derived for each individual. There was a significant association between the types of language hemispheric dominance and of intra-hemispheric intrinsic connectivity asymmetry, occurrence of Atypical_HICAs individuals being very high in the group of individuals rightward-lateralized for language (80%), reduced in the ambilateral group (19%) and rare in individuals leftward-lateralized for language (less than 3%). Quantitatively, we found a significant positive linear relationship between the HICAs and HFLI indices, with an effect of handedness on the intercept but not on the slope of this relationship. These findings demonstrate that handedness and hemispheric dominance for language are significantly but independently associated with the asymmetry of intra-hemispheric intrinsic connectivity. These findings suggest that asymmetry in intra-hemispheric connectivity is a variable phenotype shaped in part by hemispheric lateralization for language, but possibly also depending on other lateralized functions. Copyright © 2016 Elsevier Ltd. All rights reserved.

Tracer-aided modelling to explore non-linearities in flow paths, hydrological connectivity and faecal contamination risk

NASA Astrophysics Data System (ADS)

Neill, A. J.; Tetzlaff, D.; Strachan, N.; Soulsby, C.

2016-12-01

The non-linearities of runoff generation processes are strongly influenced by the connectivity of hillslopes and channel networks, particularly where overland flow is an important runoff mechanism. Despite major advances in understanding hydrological connectivity and runoff generation, the role of connectivity in the contamination of potable water supplies by faecal pathogens from grazing animals remains unclear. This is a water quality issue with serious implications for public health. Here, we sought to understand the dynamics of hydrological connectivity, flow paths and linked faecal pathogen transport in a montane catchment in Scotland with high deer populations. We firstly calibrated, within an uncertainty framework, a parsimonious tracer-aided hydrological model to daily discharge and stream isotope data. The model, developed on the basis of past empirical and tracer studies, conceptualises the catchment as three interacting hydrological source areas (dynamic saturation zone, dynamic hillslope, and groundwater) for which water fluxes, water ages and storage-based connectivity can be simulated. We next coupled several faecal indicator organism (FIO; a common indicator of faecal pathogen contamination) behaviour and transport schemes to the robust hydrological models. A further calibration was then undertaken based on the ability of each coupled model to simulate daily FIO concentrations. This gave us a final set of coupled behavioural models from which we explored how in-stream FIO dynamics could be related to the changing connectivity between the three hydrological source areas, flow paths, water ages and consequent dominant runoff generation processes. We found that high levels of FIOs were transient and episodic, and strongly correlated with periods of high connectivity through overland flow. This non-linearity in connectivity and FIO flux was successfully captured within our dynamic, tracer-aided hydrological model.

Node Deployment Algorithm Based on Connected Tree for Underwater Sensor Networks

PubMed Central

Jiang, Peng; Wang, Xingmin; Jiang, Lurong

2015-01-01

Designing an efficient deployment method to guarantee optimal monitoring quality is one of the key topics in underwater sensor networks. At present, a realistic approach of deployment involves adjusting the depths of nodes in water. One of the typical algorithms used in such process is the self-deployment depth adjustment algorithm (SDDA). This algorithm mainly focuses on maximizing network coverage by constantly adjusting node depths to reduce coverage overlaps between two neighboring nodes, and thus, achieves good performance. However, the connectivity performance of SDDA is irresolute. In this paper, we propose a depth adjustment algorithm based on connected tree (CTDA). In CTDA, the sink node is used as the first root node to start building a connected tree. Finally, the network can be organized as a forest to maintain network connectivity. Coverage overlaps between the parent node and the child node are then reduced within each sub-tree to optimize coverage. The hierarchical strategy is used to adjust the distance between the parent node and the child node to reduce node movement. Furthermore, the silent mode is adopted to reduce communication cost. Simulations show that compared with SDDA, CTDA can achieve high connectivity with various communication ranges and different numbers of nodes. Moreover, it can realize coverage as high as that of SDDA with various sensing ranges and numbers of nodes but with less energy consumption. Simulations under sparse environments show that the connectivity and energy consumption performances of CTDA are considerably better than those of SDDA. Meanwhile, the connectivity and coverage performances of CTDA are close to those depth adjustment algorithms base on connected dominating set (CDA), which is an algorithm similar to CTDA. However, the energy consumption of CTDA is less than that of CDA, particularly in sparse underwater environments. PMID:26184209

Simulation of ground-water flow to assess geohydrologic factors and their effect on source-water areas for bedrock wells in Connecticut

USGS Publications Warehouse

Starn, J. Jeffrey; Stone, Janet Radway

2005-01-01

Generic ground-water-flow simulation models show that geohydrologic factors?fracture types, fracture geometry, and surficial materials?affect the size, shape, and location of source-water areas for bedrock wells. In this study, conducted by the U.S. Geological Survey in cooperation with the Connecticut Department of Public Health, ground-water flow was simulated to bedrock wells in three settings?on hilltops and hillsides with no surficial aquifer, in a narrow valley with a surficial aquifer, and in a broad valley with a surficial aquifer?to show how different combinations of geohydrologic factors in different topographic settings affect the dimensions and locations of source-water areas in Connecticut. Three principal types of fractures are present in bedrock in Connecticut?(1) Layer-parallel fractures, which developed as partings along bedding in sedimentary rock and compositional layering or foliation in metamorphic rock (dips of these fractures can be gentle or steep); (2) unroofing joints, which developed as strain-release fractures parallel to the land surface as overlying rock was removed by erosion through geologic time; and (3) cross fractures and joints, which developed as a result of tectonically generated stresses that produced typically near-vertical or steeply dipping fractures. Fracture geometry is defined primarily by the presence or absence of layering in the rock unit, and, if layered, by the angle of dip in the layering. Where layered rocks dip steeply, layer-parallel fracturing generally is dominant; unroofing joints also are typically well developed. Where layered rocks dip gently, layer-parallel fracturing also is dominant, and connections among these fractures are provided only by the cross fractures. In gently dipping rocks, unroofing joints generally do not form as a separate fracture set; instead, strain release from unroofing has occurred along gently dipping layer-parallel fractures, enhancing their aperture. In nonlayered and variably layered rocks, layer-parallel fracturing is absent or poorly developed; fracturing is dominated by well-developed subhorizontal unroofing joints and steeply dipping, tectonically generated fractures and (or) cooling joints. Cross fractures (or cooling joints) in nonlayered and variably layered rocks have more random orientations than in layered rocks. Overall, nonlayered or variably layered rocks do not have a strongly developed fracture direction. Generic ground-water-flow simulation models showed that fracture geometry and other geohydrologic factors affect the dimensions and locations of source-water areas for bedrock wells. In general, source-water areas to wells reflect the direction of ground-water flow, which mimics the land-surface topography. Source-water areas to wells in a hilltop setting were not affected greatly by simulated fracture zones, except for an extensive vertical fracture zone. Source-water areas to wells in a hillside setting were not affected greatly by simulated fracture zones, except for the combination of a subhorizontal fracture zone and low bedrock vertical hydraulic conductivity, as might be the case where an extensive subhorizontal fracture zone is not connected or is poorly connected to the surface through vertical fractures. Source-water areas to wells in a narrow valley setting reflect complex ground-water-flow paths. The typical flow path originates in the uplands and passes through either till or bedrock into the surficial aquifer, although only a small area of the surficial aquifer actually contributes water to the well. Source-water areas in uplands can include substantial areas on both sides of a river. Source-water areas for wells in this setting are affected mainly by the rate of ground-water recharge and by the degree of anisotropy. Source-water areas to wells in a broad valley setting (bedrock with a low angle of dip) are affected greatly by fracture properties. The effect of a given fracture is to channel the

Bacterioplankton assemblages in coastal ponds reflect the influence of hydrology and geomorphological setting.

PubMed

Huggett, Megan J; Kavazos, Christopher R J; Bernasconi, Rachele; Czarnik, Robert; Horwitz, Pierre

2017-06-01

The factors that shape microbial community assembly in aquatic ecosystems have been widely studied; yet it is still unclear how distinct communities within a connected landscape influence one another. Coastal lakes are recipients of, and thus are connected to, both marine and terrestrial environments. Thus, they may host microbial assemblages that reflect the relative degree of influence by, and connectivity to, either system. In order to address this idea, we interrogated microbial community diversity at 49 sites in seven ponds in two seasons in the Lake MacLeod basin, a system fed by seawater flowing inland through underground karst. Environmental and spatial variation within ponds explain <9% of the community structure, while identity of the pond that samples were taken from explains 50% of community variation. That is, ponds each host distinct assemblages despite similarities in size, environment and position in the landscape, indicating a dominant role for local species sorting. The ponds contain a substantial amount of previously unknown microbial taxa, reflecting the unusual nature of this inland system. Rare marine taxa, possibly dispersed from seawater assemblages via the underground karst connection, are abundant within the inland system, suggesting an important role for regional dispersal within the metacommunities. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Brain Dominance & Self-Actualization.

ERIC Educational Resources Information Center

Bernhoft, Franklin O.

Numerous areas associated with brain dominance have been researched since Bogen and Sperry's work with split-brain patients in the 1960s, but only slight attention has been given to the connection between brain dominance and personality. No study appears in the literature seeking to understand optimal mental health as defined by Maslow's…

Observational Signatures of Magnetic Reconnection

NASA Technical Reports Server (NTRS)

Savage, Sabrina

2014-01-01

Magnetic reconnection is often referred to as the primary source of energy release during solar flares. Directly observing reconnection occurring in the solar atmosphere, however, is not trivial considering that the scale size of the diffusion region is magnitudes smaller than the observational capabilities of current instrumentation, and coronal magnetic field measurements are not currently sufficient to capture the process. Therefore, predicting and studying observationally feasible signatures of the precursors and consequences of reconnection is necessary for guiding and verifying the simulations that dominate our understanding. I will present a set of such observations, particularly in connection with long-duration solar events, and compare them with recent simulations and theoretical predictions.

Solar array construction

NASA Technical Reports Server (NTRS)

Crouthamel, Marvin S. (Inventor); Coyle, Peter J. (Inventor)

1982-01-01

An interconnect tab on each cell of a first set of circular solar cells connects that cell in series with an adjacent cell in the set. This set of cells is arranged in alternate columns and rows of an array and a second set of similar cells is arranged in the remaining alternate columns and rows of the array. Three interconnect tabs on each solar cell of the said second set are employed to connect the cells of the second set to one another, in series and to connect the cells of the second set to those of the first set in parallel. Some tabs (making parallel connections) connect the same surface regions of adjacent cells to one another and others (making series connections) connect a surface region of one cell to the opposite surface region of an adjacent cell; however, the tabs are so positioned that the array may be easily assembled by depositing the cells in a certain sequence and in proper orientation.

Preferential degradation of cognitive networks differentiates Alzheimer's disease from ageing.

PubMed

Chhatwal, Jasmeer P; Schultz, Aaron P; Johnson, Keith A; Hedden, Trey; Jaimes, Sehily; Benzinger, Tammie L S; Jack, Clifford; Ances, Beau M; Ringman, John M; Marcus, Daniel S; Ghetti, Bernardino; Farlow, Martin R; Danek, Adrian; Levin, Johannes; Yakushev, Igor; Laske, Christoph; Koeppe, Robert A; Galasko, Douglas R; Xiong, Chengjie; Masters, Colin L; Schofield, Peter R; Kinnunen, Kirsi M; Salloway, Stephen; Martins, Ralph N; McDade, Eric; Cairns, Nigel J; Buckles, Virginia D; Morris, John C; Bateman, Randall; Sperling, Reisa A

2018-05-01

Converging evidence from structural, metabolic and functional connectivity MRI suggests that neurodegenerative diseases, such as Alzheimer's disease, target specific neural networks. However, age-related network changes commonly co-occur with neuropathological cascades, limiting efforts to disentangle disease-specific alterations in network function from those associated with normal ageing. Here we elucidate the differential effects of ageing and Alzheimer's disease pathology through simultaneous analyses of two functional connectivity MRI datasets: (i) young participants harbouring highly-penetrant mutations leading to autosomal-dominant Alzheimer's disease from the Dominantly Inherited Alzheimer's Network (DIAN), an Alzheimer's disease cohort in which age-related comorbidities are minimal and likelihood of progression along an Alzheimer's disease trajectory is extremely high; and (ii) young and elderly participants from the Harvard Aging Brain Study, a cohort in which imaging biomarkers of amyloid burden and neurodegeneration can be used to disambiguate ageing alone from preclinical Alzheimer's disease. Consonant with prior reports, we observed the preferential degradation of cognitive (especially the default and dorsal attention networks) over motor and sensory networks in early autosomal-dominant Alzheimer's disease, and found that this distinctive degradation pattern was magnified in more advanced stages of disease. Importantly, a nascent form of the pattern observed across the autosomal-dominant Alzheimer's disease spectrum was also detectable in clinically normal elderly with clear biomarker evidence of Alzheimer's disease pathology (preclinical Alzheimer's disease). At the more granular level of individual connections between node pairs, we observed that connections within cognitive networks were preferentially targeted in Alzheimer's disease (with between network connections relatively spared), and that connections between positively coupled nodes (correlations) were preferentially degraded as compared to connections between negatively coupled nodes (anti-correlations). In contrast, ageing in the absence of Alzheimer's disease biomarkers was characterized by a far less network-specific degradation across cognitive and sensory networks, of between- and within-network connections, and of connections between positively and negatively coupled nodes. We go on to demonstrate that formalizing the differential patterns of network degradation in ageing and Alzheimer's disease may have the practical benefit of yielding connectivity measurements that highlight early Alzheimer's disease-related connectivity changes over those due to age-related processes. Together, the contrasting patterns of connectivity in Alzheimer's disease and ageing add to prior work arguing against Alzheimer's disease as a form of accelerated ageing, and suggest multi-network composite functional connectivity MRI metrics may be useful in the detection of early Alzheimer's disease-specific alterations co-occurring with age-related connectivity changes. More broadly, our findings are consistent with a specific pattern of network degradation associated with the spreading of Alzheimer's disease pathology within targeted neural networks.

Estimating network parameters from combined dynamics of firing rate and irregularity of single neurons.

PubMed

Hamaguchi, Kosuke; Riehle, Alexa; Brunel, Nicolas

2011-01-01

High firing irregularity is a hallmark of cortical neurons in vivo, and modeling studies suggest a balance of excitation and inhibition is necessary to explain this high irregularity. Such a balance must be generated, at least partly, from local interconnected networks of excitatory and inhibitory neurons, but the details of the local network structure are largely unknown. The dynamics of the neural activity depends on the local network structure; this in turn suggests the possibility of estimating network structure from the dynamics of the firing statistics. Here we report a new method to estimate properties of the local cortical network from the instantaneous firing rate and irregularity (CV(2)) under the assumption that recorded neurons are a part of a randomly connected sparse network. The firing irregularity, measured in monkey motor cortex, exhibits two features; many neurons show relatively stable firing irregularity in time and across different task conditions; the time-averaged CV(2) is widely distributed from quasi-regular to irregular (CV(2) = 0.3-1.0). For each recorded neuron, we estimate the three parameters of a local network [balance of local excitation-inhibition, number of recurrent connections per neuron, and excitatory postsynaptic potential (EPSP) size] that best describe the dynamics of the measured firing rates and irregularities. Our analysis shows that optimal parameter sets form a two-dimensional manifold in the three-dimensional parameter space that is confined for most of the neurons to the inhibition-dominated region. High irregularity neurons tend to be more strongly connected to the local network, either in terms of larger EPSP and inhibitory PSP size or larger number of recurrent connections, compared with the low irregularity neurons, for a given excitatory/inhibitory balance. Incorporating either synaptic short-term depression or conductance-based synapses leads many low CV(2) neurons to move to the excitation-dominated region as well as to an increase of EPSP size.

Are litter decomposition and fire linked through plant species traits?

PubMed

Cornelissen, Johannes H C; Grootemaat, Saskia; Verheijen, Lieneke M; Cornwell, William K; van Bodegom, Peter M; van der Wal, René; Aerts, Rien

2017-11-01

Contents 653 I. 654 II. 657 III. 659 IV. 661 V. 662 VI. 663 VII. 665 665 References 665 SUMMARY: Biological decomposition and wildfire are connected carbon release pathways for dead plant material: slower litter decomposition leads to fuel accumulation. Are decomposition and surface fires also connected through plant community composition, via the species' traits? Our central concept involves two axes of trait variation related to decomposition and fire. The 'plant economics spectrum' (PES) links biochemistry traits to the litter decomposability of different fine organs. The 'size and shape spectrum' (SSS) includes litter particle size and shape and their consequent effect on fuel bed structure, ventilation and flammability. Our literature synthesis revealed that PES-driven decomposability is largely decoupled from predominantly SSS-driven surface litter flammability across species; this finding needs empirical testing in various environmental settings. Under certain conditions, carbon release will be dominated by decomposition, while under other conditions litter fuel will accumulate and fire may dominate carbon release. Ecosystem-level feedbacks between decomposition and fire, for example via litter amounts, litter decomposition stage, community-level biotic interactions and altered environment, will influence the trait-driven effects on decomposition and fire. Yet, our conceptual framework, explicitly comparing the effects of two plant trait spectra on litter decomposition vs fire, provides a promising new research direction for better understanding and predicting Earth surface carbon dynamics. © 2017 The Authors. New Phytologist © 2017 New Phytologist Trust.

Resting-state functional connectivity predicts the strength of hemispheric lateralization for language processing in temporal lobe epilepsy and normals.

PubMed

Doucet, Gaëlle E; Pustina, Dorian; Skidmore, Christopher; Sharan, Ashwini; Sperling, Michael R; Tracy, Joseph I

2015-01-01

In temporal lobe epilepsy (TLE), determining the hemispheric specialization for language before surgery is critical to preserving a patient's cognitive abilities post-surgery. To date, the major techniques utilized are limited by the capacity of patients to efficiently realize the task. We determined whether resting-state functional connectivity (rsFC) is a reliable predictor of language hemispheric dominance in right and left TLE patients, relative to controls. We chose three subregions of the inferior frontal cortex (pars orbitalis, pars triangularis, and pars opercularis) as the seed regions. All participants performed both a verb generation task and a resting-state fMRI procedure. Based on the language task, we computed a laterality index (LI) for the resulting network. This revealed that 96% of the participants were left-hemisphere dominant, although there remained a large degree of variability in the strength of left lateralization. We tested whether LI correlated with rsFC values emerging from each seed. We revealed a set of regions that was specific to each group. Unique correlations involving the epileptic mesial temporal lobe were revealed for the right and left TLE patients, but not for the controls. Importantly, for both TLE groups, the rsFC emerging from a contralateral seed was the most predictive of LI. Overall, our data depict the broad patterns of rsFC that support strong versus weak left hemisphere language laterality. This project provides the first evidence that rsFC data may potentially be used on its own to verify the strength of hemispheric dominance for language in impaired or pathologic populations. © 2014 Wiley Periodicals, Inc.

A novel spatially-explicit condition for the onset of waterborne diseases in complex environments

NASA Astrophysics Data System (ADS)

Mari, L.; Gatto, M.; Bertuzzo, E.; Casagrandi, R.; Righetto, L.; Rodriguez-Iturbe, I.; Rinaldo, A.

2012-12-01

In spatial models of waterborne infections the condition that all the local reproduction numbers be larger than one is neither necessary nor sufficient for outbreaks to occur. Here, to properly determine epidemic onset conditions, we examine the transition from stable to unstable of the disease-free equilibrium of a system of nonlinear differential equations characterizing the evolution of susceptible and infected individuals within their respective settlements, and pathogen concentration in their accessible environment. Two different network connectivity layers are assumed to link human settlements: hydrologic pathways serve as ecological corridors for pathogens, while human mobility acts as disease vehicle through susceptibles contracting the disease and asymptomatic infectives shedding bacteria at their temporary destinations. We show that an epidemic outbreak can be triggered if the dominant eigenvalue of a generalized reproduction matrix G0, suitably accounting for spatial distribution of human settlements, hydrological pathways for pathogen dispersal and pathogen redistribution mechanisms due to human mobility, is larger than unity. Matrix G0 and its dominant eigenvalue thus replace the usual reproduction number whenever spatial effects on disease propagation cannot be ignored. Conversely, our novel criterion decays into the standard onset condition based on local reproduction numbers in nonspatial settings. By analyzing realistic test cases we show that within a connected network system the disease can start even if all the local reproduction numbers are smaller than unity, or might not start even if all the local reproduction numbers are larger than unity. We also show that onset geography in complex environments is linked to the dominant eigenvector of matrix G0. Applications to cholera outbreaks in developing countries demonstrate that our approach can be successfully used for disease prediction and emergency management.

Freedom as Non-Domination, Standards and the Negotiated Curriculum

ERIC Educational Resources Information Center

Hopkins, Neil

2015-01-01

This article investigates the application of Philip Pettit's concept of freedom as non-domination to the issues of educational standards and the negotiated curriculum. The article will argue that freedom as non-domination (and the connected concept of debating contestations as part of a legitimate democratic state) shines a critical light on…

In the Shadows of Dominant Cultures: The Elusive Definition of Giftedness

ERIC Educational Resources Information Center

Polyzoi, Eleoussa; Haydey, Donna Copsey

2012-01-01

In this commentary, the authors contend that Persson's (2012a) paper, Cultural Variation and Dominance in a Globalised Knowledge-Economy: Towards a Culture-Sensitive Research Paradigm in the Science of Giftedness, lacks conciseness in defining the connections between the significance of cultural dominance and the definition of giftedness. However,…

Improvement of a free software tool for the assessment of sediment connectivity

NASA Astrophysics Data System (ADS)

Crema, Stefano; Lanni, Cristiano; Goldin, Beatrice; Marchi, Lorenzo; Cavalli, Marco

2015-04-01

Sediment connectivity expresses the degree of linkage that controls sediment fluxes throughout landscape, in particular between sediment sources and downstream areas. The assessment of sediment connectivity becomes a key issue when dealing with risk mitigation and priorities of intervention in the territory. In this work, the authors report the improvements made to an open source and stand-alone application (SedInConnect, http://www.sedalp.eu/download/tools.shtml), along with extensive applications to alpine catchments. SedInConnect calculates a sediment connectivity index as expressed in Cavalli et al. (2013); the software improvements consisted primarily in the introduction of the sink feature, i.e. areas that act as traps for sediment produced upstream (e.g., lakes, sediment traps). Based on user-defined sinks, the software decouples those parts of the catchment that do not deliver sediment to a selected target of interest (e.g., fan apex, main drainage network). In this way the assessment of sediment connectivity is achieved by taking in consideration effective sediment contributing areas. Sediment connectivity analysis has been carried out on several catchments in the South Tyrol alpine area (Northern Italy) with the goal of achieving a fast and objective characterization of the topographic control on sediment transfer. In addition to depicting the variability of sediment connectivity inside each basin, the index of connectivity has proved to be a valuable indicator of the dominant process characterizing the basin sediment dynamics (debris flow, bedload, mixed behavior). The characterization of the dominant process is of great importance for the hazard and risk assessment in mountain areas, and for choice and design of structural and non-structural intervention measures. The recognition of the dominant sediment transport process by the index of connectivity is in agreement with evidences arising from post-event field surveys and with the application of morphometric indexes, such as the Melton ruggedness number, commonly used for discriminating debris-flow catchments from bedload catchments. References: Cavalli, M., Trevisani, S., Comiti, F., Marchi, L., 2013. Geomorphometric assessment of spatial sediment connectivity in small Alpine catchments. Geomorphology 188,31-41. doi:10.1016/j.geomorph.2012.05.007

Cardiovascular functioning, personality, and the social world: the domain of hierarchical power.

PubMed

Newton, Tamara L

2009-02-01

The present paper considers connections between cardiovascular functioning (i.e., disease status and acute stress responses) and social dominance, and its counterpart, social submissiveness, both of which are part of the broader domain of "hierarchical power" [Bugental, D.B., 2000. Acquisition of the algorithms of social life: a domain-based approach. Psychological Bulletin 126, 187-219]. Empirical research on connections between dominance/submissiveness and cardiovascular morbidity and mortality in humans is reviewed, as is research on dominance/submissiveness and cardiovascular reactivity to, and recovery from, acute stressors. Three general conclusions are established. First, in both cross-sectional and longitudinal investigations, trait and behavioral indicators of dominance have been positively associated with cardiovascular disease severity, incidence, and progression, whereas preliminary evidence from two studies suggests that trait submissiveness may protect against poorer disease outcomes. Second, among men and women, trait dominance is associated with reactivity to and recovery from acute stressors, particularly social challenges. Third, linkages between dominance/submissiveness and cardiovascular functioning, especially cardiovascular reactivity, are characterized by gender-specific patterning, and this patterning emerges as a function of social context. Implications for the next generation of research concerning social dominance, gender, and cardiovascular functioning are discussed.

Topology for Dominance for Network of Multi-Agent System

NASA Astrophysics Data System (ADS)

Szeto, K. Y.

2007-05-01

The resource allocation problem in evolving two-dimensional point patterns is investigated for the existence of good strategies for the construction of initial configuration that leads to fast dominance of the pattern by one single species, which can be interpreted as market dominance by a company in the context of multi-agent systems in econophysics. For hexagonal lattice, certain special topological arrangements of the resource in two-dimensions, such as rings, lines and clusters have higher probability of dominance, compared to random pattern. For more complex networks, a systematic way to search for a stable and dominant strategy of resource allocation in the changing environment is found by means of genetic algorithm. Five typical features can be summarized by means of the distribution function for the local neighborhood of friends and enemies as well as the local clustering coefficients: (1) The winner has more triangles than the loser has. (2) The winner likes to form clusters as the winner tends to connect with other winner rather than with losers; while the loser tends to connect with winners rather than losers. (3) The distribution function of friends as well as enemies for the winner is broader than the corresponding distribution function for the loser. (4) The connectivity at which the peak of the distribution of friends for the winner occurs is larger than that of the loser; while the peak values for friends for winners is lower. (5) The connectivity at which the peak of the distribution of enemies for the winner occurs is smaller than that of the loser; while the peak values for enemies for winners is lower. These five features appear to be general, at least in the context of two-dimensional hexagonal lattices of various sizes, hierarchical lattice, Voronoi diagrams, as well as high-dimensional random networks. These general local topological properties of networks are relevant to strategists aiming at dominance in evolving patterns when the interaction between the agents is local.

An Evaluation of the Left-Brain vs. Right-Brain Hypothesis with Resting State Functional Connectivity Magnetic Resonance Imaging

PubMed Central

Nielsen, Jared A.; Zielinski, Brandon A.; Ferguson, Michael A.; Lainhart, Janet E.; Anderson, Jeffrey S.

2013-01-01

Lateralized brain regions subserve functions such as language and visuospatial processing. It has been conjectured that individuals may be left-brain dominant or right-brain dominant based on personality and cognitive style, but neuroimaging data has not provided clear evidence whether such phenotypic differences in the strength of left-dominant or right-dominant networks exist. We evaluated whether strongly lateralized connections covaried within the same individuals. Data were analyzed from publicly available resting state scans for 1011 individuals between the ages of 7 and 29. For each subject, functional lateralization was measured for each pair of 7266 regions covering the gray matter at 5-mm resolution as a difference in correlation before and after inverting images across the midsagittal plane. The difference in gray matter density between homotopic coordinates was used as a regressor to reduce the effect of structural asymmetries on functional lateralization. Nine left- and 11 right-lateralized hubs were identified as peaks in the degree map from the graph of significantly lateralized connections. The left-lateralized hubs included regions from the default mode network (medial prefrontal cortex, posterior cingulate cortex, and temporoparietal junction) and language regions (e.g., Broca Area and Wernicke Area), whereas the right-lateralized hubs included regions from the attention control network (e.g., lateral intraparietal sulcus, anterior insula, area MT, and frontal eye fields). Left- and right-lateralized hubs formed two separable networks of mutually lateralized regions. Connections involving only left- or only right-lateralized hubs showed positive correlation across subjects, but only for connections sharing a node. Lateralization of brain connections appears to be a local rather than global property of brain networks, and our data are not consistent with a whole-brain phenotype of greater “left-brained” or greater “right-brained” network strength across individuals. Small increases in lateralization with age were seen, but no differences in gender were observed. PMID:23967180

An evaluation of the left-brain vs. right-brain hypothesis with resting state functional connectivity magnetic resonance imaging.

PubMed

Nielsen, Jared A; Zielinski, Brandon A; Ferguson, Michael A; Lainhart, Janet E; Anderson, Jeffrey S

2013-01-01

Lateralized brain regions subserve functions such as language and visuospatial processing. It has been conjectured that individuals may be left-brain dominant or right-brain dominant based on personality and cognitive style, but neuroimaging data has not provided clear evidence whether such phenotypic differences in the strength of left-dominant or right-dominant networks exist. We evaluated whether strongly lateralized connections covaried within the same individuals. Data were analyzed from publicly available resting state scans for 1011 individuals between the ages of 7 and 29. For each subject, functional lateralization was measured for each pair of 7266 regions covering the gray matter at 5-mm resolution as a difference in correlation before and after inverting images across the midsagittal plane. The difference in gray matter density between homotopic coordinates was used as a regressor to reduce the effect of structural asymmetries on functional lateralization. Nine left- and 11 right-lateralized hubs were identified as peaks in the degree map from the graph of significantly lateralized connections. The left-lateralized hubs included regions from the default mode network (medial prefrontal cortex, posterior cingulate cortex, and temporoparietal junction) and language regions (e.g., Broca Area and Wernicke Area), whereas the right-lateralized hubs included regions from the attention control network (e.g., lateral intraparietal sulcus, anterior insula, area MT, and frontal eye fields). Left- and right-lateralized hubs formed two separable networks of mutually lateralized regions. Connections involving only left- or only right-lateralized hubs showed positive correlation across subjects, but only for connections sharing a node. Lateralization of brain connections appears to be a local rather than global property of brain networks, and our data are not consistent with a whole-brain phenotype of greater "left-brained" or greater "right-brained" network strength across individuals. Small increases in lateralization with age were seen, but no differences in gender were observed.

Two-Hierarchy Entanglement Swapping for a Linear Optical Quantum Repeater

NASA Astrophysics Data System (ADS)

Xu, Ping; Yong, Hai-Lin; Chen, Luo-Kan; Liu, Chang; Xiang, Tong; Yao, Xing-Can; Lu, He; Li, Zheng-Da; Liu, Nai-Le; Li, Li; Yang, Tao; Peng, Cheng-Zhi; Zhao, Bo; Chen, Yu-Ao; Pan, Jian-Wei

2017-10-01

Quantum repeaters play a significant role in achieving long-distance quantum communication. In the past decades, tremendous effort has been devoted towards constructing a quantum repeater. As one of the crucial elements, entanglement has been created in different memory systems via entanglement swapping. The realization of j -hierarchy entanglement swapping, i.e., connecting quantum memory and further extending the communication distance, is important for implementing a practical quantum repeater. Here, we report the first demonstration of a fault-tolerant two-hierarchy entanglement swapping with linear optics using parametric down-conversion sources. In the experiment, the dominant or most probable noise terms in the one-hierarchy entanglement swapping, which is on the same order of magnitude as the desired state and prevents further entanglement connections, are automatically washed out by a proper design of the detection setting, and the communication distance can be extended. Given suitable quantum memory, our techniques can be directly applied to implementing an atomic ensemble based quantum repeater, and are of significant importance in the scalable quantum information processing.

Two-Hierarchy Entanglement Swapping for a Linear Optical Quantum Repeater.

PubMed

Xu, Ping; Yong, Hai-Lin; Chen, Luo-Kan; Liu, Chang; Xiang, Tong; Yao, Xing-Can; Lu, He; Li, Zheng-Da; Liu, Nai-Le; Li, Li; Yang, Tao; Peng, Cheng-Zhi; Zhao, Bo; Chen, Yu-Ao; Pan, Jian-Wei

2017-10-27

Quantum repeaters play a significant role in achieving long-distance quantum communication. In the past decades, tremendous effort has been devoted towards constructing a quantum repeater. As one of the crucial elements, entanglement has been created in different memory systems via entanglement swapping. The realization of j-hierarchy entanglement swapping, i.e., connecting quantum memory and further extending the communication distance, is important for implementing a practical quantum repeater. Here, we report the first demonstration of a fault-tolerant two-hierarchy entanglement swapping with linear optics using parametric down-conversion sources. In the experiment, the dominant or most probable noise terms in the one-hierarchy entanglement swapping, which is on the same order of magnitude as the desired state and prevents further entanglement connections, are automatically washed out by a proper design of the detection setting, and the communication distance can be extended. Given suitable quantum memory, our techniques can be directly applied to implementing an atomic ensemble based quantum repeater, and are of significant importance in the scalable quantum information processing.

Dynamic network expansion, contraction, and connectivity in the river corridor of mountain stream network

NASA Astrophysics Data System (ADS)

Ward, A. S.; Schmadel, N.; Wondzell, S. M.

2017-12-01

River networks are broadly recognized to expand and contract in response to hydrologic forcing. Additionally, the individual controls on river corridor dynamics of hydrologic forcing and geologic setting are well recognized. However, we currently lack tools to integrate our understanding of process dynamics in the river corridor and make predictions at the scale of river networks. In this study, we develop a perceptual model of the river corridor in mountain river networks, translate this into a reduced-complexity mechanistic model, and implement the model in a well-studied headwater catchment. We found that the river network was most sensitive to hydrologic dynamics under the lowest discharges (Qgauge < 1 L s-1). We also demonstrate a discharge-dependence on the dominant controls on network expansion, contraction, and river corridor exchange. Finally, we suggest this parsimonious model will be useful to managers of water resources who need to estimate connectivity and flow initiation location along the river corridor over broad, unstudied catchments.

Visual search, visual streams, and visual architectures.

PubMed

Green, M

1991-10-01

Most psychological, physiological, and computational models of early vision suggest that retinal information is divided into a parallel set of feature modules. The dominant theories of visual search assume that these modules form a "blackboard" architecture: a set of independent representations that communicate only through a central processor. A review of research shows that blackboard-based theories, such as feature-integration theory, cannot easily explain the existing data. The experimental evidence is more consistent with a "network" architecture, which stresses that: (1) feature modules are directly connected to one another, (2) features and their locations are represented together, (3) feature detection and integration are not distinct processing stages, and (4) no executive control process, such as focal attention, is needed to integrate features. Attention is not a spotlight that synthesizes objects from raw features. Instead, it is better to conceptualize attention as an aperture which masks irrelevant visual information.

Method and apparatus for connecting high voltage leads to a high temperature super-conducting transformer

DOEpatents

Golner, Thomas M.; Mehta, Shirish P.

2005-07-26

A method and apparatus for connecting high voltage leads to a super-conducting transformer is provided that includes a first super-conducting coil set, a second super-conducting coil set, and a third super-conducting coil set. The first, second and third super-conducting coil sets are connected via an insulated interconnect system that includes insulated conductors and insulated connectors that are utilized to connect the first, second, and third super-conducting coil sets to the high voltage leads.

Networks of Interacting Processes: Relationships Between Drivers and Deltaic Variables to Understand Water and Sediment Transport in Wax Lake Delta, Coastal Louisiana

NASA Astrophysics Data System (ADS)

Sendrowski, A.; Passalacqua, P.; Wagner, W.; Mohrig, D. C.; Meselhe, E. A.; Sadid, K. M.; Castañeda-Moya, E.; Twilley, R.

2017-12-01

Studying distributary channel networks in river deltaic systems provides important insight into deltaic functioning and evolution. This view of networks highlights the physical connection along channels and can also encompass the structural link between channels and deltaic islands (termed structural connectivity). An alternate view of the deltaic network is one composed of interacting processes, such as relationships between external drivers (e.g., river discharge, tides, and wind) and internal deltaic response variables (e.g., water level and sediment concentration). This network, also referred to as process connectivity, is dynamic across space and time, often comprises nonlinear relationships, and contributes to the development of complex channel networks and ecologically rich island platforms. The importance of process connectivity has been acknowledged, however, few studies have directly quantified these network interactions. In this work, we quantify process connections in Wax Lake Delta (WLD), coastal Louisiana. WLD is a naturally prograding delta that serves as an analogue for river diversion projects, thus it provides an excellent setting for understanding the influence of river discharge, tides, and wind on water and sediment in a delta. Time series of water level and sediment concentration were collected in three channels from November 2013 to February 2014, while water level and turbidity were collected on an island from April 2014 to August 2015. Additionally, a model run on WLD bathymetry generated two years of sediment concentration time series in multiple channels. River discharge, tide, and wind measurements were collected from the USGS and NOAA, respectively. We analyze this data with information theory (IT), a set of statistics that measure uncertainty in signals and communication between signals. Using IT, the timescale, strength, and direction of network links are quantified by measuring the synchronization and direct influence from one variable to another. We compare channel and island process connections, which show distinct differences. Our study captures the temporal evolution of variable transport at multiple locations. While WLD is river dominated, tides and wind show unique transport signatures related to tidal spring and neap transitions and wind events.

Evoked effective connectivity of the human neocortex.

PubMed

Entz, László; Tóth, Emília; Keller, Corey J; Bickel, Stephan; Groppe, David M; Fabó, Dániel; Kozák, Lajos R; Erőss, Loránd; Ulbert, István; Mehta, Ashesh D

2014-12-01

The role of cortical connectivity in brain function and pathology is increasingly being recognized. While in vivo magnetic resonance imaging studies have provided important insights into anatomical and functional connectivity, these methodologies are limited in their ability to detect electrophysiological activity and the causal relationships that underlie effective connectivity. Here, we describe results of cortico-cortical evoked potential (CCEP) mapping using single pulse electrical stimulation in 25 patients undergoing seizure monitoring with subdural electrode arrays. Mapping was performed by stimulating adjacent electrode pairs and recording CCEPs from the remainder of the electrode array. CCEPs reliably revealed functional networks and showed an inverse relationship to distance between sites. Coregistration to Brodmann areas (BA) permitted group analysis. Connections were frequently directional with 43% of early responses and 50% of late responses of connections reflecting relative dominance of incoming or outgoing connections. The most consistent connections were seen as outgoing from motor cortex, BA6-BA9, somatosensory (SS) cortex, anterior cingulate cortex, and Broca's area. Network topology revealed motor, SS, and premotor cortices along with BA9 and BA10 and language areas to serve as hubs for cortical connections. BA20 and BA39 demonstrated the most consistent dominance of outdegree connections, while BA5, BA7, auditory cortex, and anterior cingulum demonstrated relatively greater indegree. This multicenter, large-scale, directional study of local and long-range cortical connectivity using direct recordings from awake, humans will aid the interpretation of noninvasive functional connectome studies. © 2014 Wiley Periodicals, Inc.

Rebuilding Biodiversity of Patagonian Marine Molluscs after the End-Cretaceous Mass Extinction

PubMed Central

Aberhan, Martin; Kiessling, Wolfgang

2014-01-01

We analysed field-collected quantitative data of benthic marine molluscs across the Cretaceous–Palaeogene boundary in Patagonia to identify patterns and processes of biodiversity reconstruction after the end-Cretaceous mass extinction. We contrast diversity dynamics from nearshore environments with those from offshore environments. In both settings, Early Palaeogene (Danian) assemblages are strongly dominated by surviving lineages, many of which changed their relative abundance from being rare before the extinction event to becoming the new dominant forms. Only a few of the species in the Danian assemblages were newly evolved. In offshore environments, however, two newly evolved Danian bivalve species attained ecological dominance by replacing two ecologically equivalent species that disappeared at the end of the Cretaceous. In both settings, the total number of Danian genera at a locality remained below the total number of late Cretaceous (Maastrichtian) genera at that locality. We suggest that biotic interactions, in particular incumbency effects, suppressed post-extinction diversity and prevented the compensation of diversity loss by originating and invading taxa. Contrary to the total number of genera at localities, diversity at the level of individual fossiliferous horizons before and after the boundary is indistinguishable in offshore environments. This indicates an evolutionary rapid rebound to pre-extinction values within less than ca 0.5 million years. In nearshore environments, by contrast, diversity of fossiliferous horizons was reduced in the Danian, and this lowered diversity lasted for the entire studied post-extinction interval. In this heterogeneous environment, low connectivity among populations may have retarded the recolonisation of nearshore habitats by survivors. PMID:25028930

[Outline on the phylogenetic history of Metazoa aging phenomenon (to the study of number of dominating pseudo-scientific concepts in biology of aging)].

PubMed

Boĭko, A G; Labas, Iu A; Gordeeva, A V

2009-01-01

Natural selection is just one of the factors determining genome evolution of Metazoa. But it's not a domineering one along with non-adaptive processes: horizontal gene transfer and input of egoistic genetic elements. That's why in phylogenesis (1) there are more genes of first Metazoa lost than new ones acquired; (2) the appearance of new genes among Metazoa branches is a very rare occasion; (3) genetically Metazoa is a homogeneous group of species with similar set of cellular mechanisms which was established in the course of evolution. The genome of first Metazoa turned to be so successful that evolution connected with organism amplification didn't demand radical changes in the genetic repertoire but it demanded changes in DNA sites regulating genes work. These facts along with the fact of existence of species of Metazoa with negligible aging overturn the core theories of aging biology which consider this or that cellular mechanism to be the initiating factor of organism's aging as sets of cellular mechanisms in aging and non-aging Metazoa forms are practically identical. That's why the basis of aging biology is in essence a collection of theories and dogmas that have never been proved but which are still in use and which have since long ago turned into a dangerous myth standing in the way of progress. If we are interested in progress of biogerontology a number of domineering pseudo scientific dogmas must be revisited. The matter of conservatism in this issue is inappropriate.

Node Self-Deployment Algorithm Based on an Uneven Cluster with Radius Adjusting for Underwater Sensor Networks

PubMed Central

Jiang, Peng; Xu, Yiming; Wu, Feng

2016-01-01

Existing move-restricted node self-deployment algorithms are based on a fixed node communication radius, evaluate the performance based on network coverage or the connectivity rate and do not consider the number of nodes near the sink node and the energy consumption distribution of the network topology, thereby degrading network reliability and the energy consumption balance. Therefore, we propose a distributed underwater node self-deployment algorithm. First, each node begins the uneven clustering based on the distance on the water surface. Each cluster head node selects its next-hop node to synchronously construct a connected path to the sink node. Second, the cluster head node adjusts its depth while maintaining the layout formed by the uneven clustering and then adjusts the positions of in-cluster nodes. The algorithm originally considers the network reliability and energy consumption balance during node deployment and considers the coverage redundancy rate of all positions that a node may reach during the node position adjustment. Simulation results show, compared to the connected dominating set (CDS) based depth computation algorithm, that the proposed algorithm can increase the number of the nodes near the sink node and improve network reliability while guaranteeing the network connectivity rate. Moreover, it can balance energy consumption during network operation, further improve network coverage rate and reduce energy consumption. PMID:26784193

Dominating Scale-Free Networks Using Generalized Probabilistic Methods

PubMed Central

Molnár,, F.; Derzsy, N.; Czabarka, É.; Székely, L.; Szymanski, B. K.; Korniss, G.

2014-01-01

We study ensemble-based graph-theoretical methods aiming to approximate the size of the minimum dominating set (MDS) in scale-free networks. We analyze both analytical upper bounds of dominating sets and numerical realizations for applications. We propose two novel probabilistic dominating set selection strategies that are applicable to heterogeneous networks. One of them obtains the smallest probabilistic dominating set and also outperforms the deterministic degree-ranked method. We show that a degree-dependent probabilistic selection method becomes optimal in its deterministic limit. In addition, we also find the precise limit where selecting high-degree nodes exclusively becomes inefficient for network domination. We validate our results on several real-world networks, and provide highly accurate analytical estimates for our methods. PMID:25200937

Evaluation of corrosion of metallic reinforcements and connections in MSE retaining walls.

DOT National Transportation Integrated Search

2008-05-01

Mechanically Stabilized Earth (MSE) retaining walls have become the dominant retained wall system on ODOT projects. The permanent MSE walls constructed on ODOT projects, in recent years, use metallic reinforcements and facing connections buried direc...

Chinook salmon use of spawning patches: relative roles of habitat quality, size, and connectivity.

PubMed

Isaak, Daniel J; Thurow, Russell F; Rieman, Bruce E; Dunham, Jason B

2007-03-01

Declines in many native fish populations have led to reassessments of management goals and shifted priorities from consumptive uses to species preservation. As management has shifted, relevant environmental characteristics have evolved from traditional metrics that described local habitat quality to characterizations of habitat size and connectivity. Despite the implications this shift has for how habitats may be prioritized for conservation, it has been rare to assess the relative importance of these habitat components. We used an information-theoretic approach to select the best models from sets of logistic regressions that linked habitat quality, size, and connectivity to the occurrence of chinook salmon (Oncorhynchus tshawytscha) nests. Spawning distributions were censused annually from 1995 to 2004, and data were complemented with field measurements that described habitat quality in 43 suitable spawning patches across a stream network that drained 1150 km2 in central Idaho. Results indicated that the most plausible models were dominated by measures of habitat size and connectivity, whereas habitat quality was of minor importance. Connectivity was the strongest predictor of nest occurrence, but connectivity interacted with habitat size, which became relatively more important when populations were reduced. Comparison of observed nest distributions to null model predictions confirmed that the habitat size association was driven by a biological mechanism when populations were small, but this association may have been an area-related sampling artifact at higher abundances. The implications for habitat management are that the size and connectivity of existing habitat networks should be maintained whenever possible. In situations where habitat restoration is occurring, expansion of existing areas or creation of new habitats in key areas that increase connectivity may be beneficial. Information about habitat size and connectivity also could be used to strategically prioritize areas for improvement of local habitat quality, with areas not meeting minimum thresholds being deemed inappropriate for pursuit of restoration activities.

Chinook salmon use of spawning patches: Relative roles of habitat quality, size, and connectivity

USGS Publications Warehouse

Isaak, D.J.; Thurow, R.F.; Rieman, B.E.; Dunham, J.B.

2007-01-01

Declines in many native fish populations have led to reassessments of management goals and shifted priorities from consumptive uses to species preservation. As management has shifted, relevant environmental characteristics have evolved from traditional metrics that described local habitat quality to characterizations of habitat size and connectivity. Despite the implications this shift has for how habitats may be prioritized for conservation, it has been rare to assess the relative importance of these habitat components. We used an information-theoretic approach to select the best models from sets of logistic regressions that linked habitat quality, size, and connectivity to the occurrence of chinook salmon (Oncorhynchus tshawytscha) nests. Spawning distributions were censused annually from 1995 to 2004, and data were complemented with field measurements that described habitat quality in 43 suitable spawning patches across a stream network that drained 1150 km 2 in central Idaho. Results indicated that the most plausible models were dominated by measures of habitat size and connectivity, whereas habitat quality was of minor importance. Connectivity was the strongest predictor of nest occurrence, but connectivity interacted with habitat size, which became relatively more important when populations were reduced. Comparison of observed nest distributions to null model predictions confirmed that the habitat size association was driven by a biological mechanism when populations were small, but this association may have been an area-related sampling artifact at higher abundances. The implications for habitat management are that the size and connectivity of existing habitat networks should be maintained whenever possible. In situations where habitat restoration is occurring, expansion of existing areas or creation of new habitats in key areas that increase connectivity may be beneficial. Information about habitat size and connectivity also could be used to strategically prioritize areas for improvement of local habitat quality, with areas not meeting minimum thresholds being deemed inappropriate for pursuit of restoration activities. ?? 2007 by the Ecological Society of America.

Dominance as a competence domain, and the evolutionary origins of respect and contempt.

PubMed

Chapais, Bernard

2017-01-01

The hypothesis of a phylogenetic connection between protorespect in primate dominance hierarchies and respect in human prestige hierarchies lies in the principle that dominance is a domain of competence like others and, hence, that high-ranking primates have protoprestige. The idea that dominant primates manifest protocontempt to subordinates suggests that "looking down on" followers is intrinsic to leadership in humans, but that the expression of contempt varies critically in relation to the socioecological context.

Effective Connectivity Reveals Right-Hemisphere Dominance in Audiospatial Perception: Implications for Models of Spatial Neglect

PubMed Central

Friston, Karl J.; Mattingley, Jason B.; Roepstorff, Andreas; Garrido, Marta I.

2014-01-01

Detecting the location of salient sounds in the environment rests on the brain's ability to use differences in sounds arriving at both ears. Functional neuroimaging studies in humans indicate that the left and right auditory hemispaces are coded asymmetrically, with a rightward attentional bias that reflects spatial attention in vision. Neuropsychological observations in patients with spatial neglect have led to the formulation of two competing models: the orientation bias and right-hemisphere dominance models. The orientation bias model posits a symmetrical mapping between one side of the sensorium and the contralateral hemisphere, with mutual inhibition of the ipsilateral hemisphere. The right-hemisphere dominance model introduces a functional asymmetry in the brain's coding of space: the left hemisphere represents the right side, whereas the right hemisphere represents both sides of the sensorium. We used Dynamic Causal Modeling of effective connectivity and Bayesian model comparison to adjudicate between these alternative network architectures, based on human electroencephalographic data acquired during an auditory location oddball paradigm. Our results support a hemispheric asymmetry in a frontoparietal network that conforms to the right-hemisphere dominance model. We show that, within this frontoparietal network, forward connectivity increases selectively in the hemisphere contralateral to the side of sensory stimulation. We interpret this finding in light of hierarchical predictive coding as a selective increase in attentional gain, which is mediated by feedforward connections that carry precision-weighted prediction errors during perceptual inference. This finding supports the disconnection hypothesis of unilateral neglect and has implications for theories of its etiology. PMID:24695717

The connection-set algebra--a novel formalism for the representation of connectivity structure in neuronal network models.

PubMed

Djurfeldt, Mikael

2012-07-01

The connection-set algebra (CSA) is a novel and general formalism for the description of connectivity in neuronal network models, from small-scale to large-scale structure. The algebra provides operators to form more complex sets of connections from simpler ones and also provides parameterization of such sets. CSA is expressive enough to describe a wide range of connection patterns, including multiple types of random and/or geometrically dependent connectivity, and can serve as a concise notation for network structure in scientific writing. CSA implementations allow for scalable and efficient representation of connectivity in parallel neuronal network simulators and could even allow for avoiding explicit representation of connections in computer memory. The expressiveness of CSA makes prototyping of network structure easy. A C+ + version of the algebra has been implemented and used in a large-scale neuronal network simulation (Djurfeldt et al., IBM J Res Dev 52(1/2):31-42, 2008b) and an implementation in Python has been publicly released.

Generalized reproduction numbers and the prediction of patterns in waterborne disease

PubMed Central

Gatto, Marino; Mari, Lorenzo; Bertuzzo, Enrico; Casagrandi, Renato; Righetto, Lorenzo; Rodriguez-Iturbe, Ignacio; Rinaldo, Andrea

2012-01-01

Understanding, predicting, and controlling outbreaks of waterborne diseases are crucial goals of public health policies, but pose challenging problems because infection patterns are influenced by spatial structure and temporal asynchrony. Although explicit spatial modeling is made possible by widespread data mapping of hydrology, transportation infrastructure, population distribution, and sanitation, the precise condition under which a waterborne disease epidemic can start in a spatially explicit setting is still lacking. Here we show that the requirement that all the local reproduction numbers be larger than unity is neither necessary nor sufficient for outbreaks to occur when local settlements are connected by networks of primary and secondary infection mechanisms. To determine onset conditions, we derive general analytical expressions for a reproduction matrix , explicitly accounting for spatial distributions of human settlements and pathogen transmission via hydrological and human mobility networks. At disease onset, a generalized reproduction number (the dominant eigenvalue of ) must be larger than unity. We also show that geographical outbreak patterns in complex environments are linked to the dominant eigenvector and to spectral properties of . Tests against data and computations for the 2010 Haiti and 2000 KwaZulu-Natal cholera outbreaks, as well as against computations for metapopulation networks, demonstrate that eigenvectors of provide a synthetic and effective tool for predicting the disease course in space and time. Networked connectivity models, describing the interplay between hydrology, epidemiology, and social behavior sustaining human mobility, thus prove to be key tools for emergency management of waterborne infections. PMID:23150538

Functional connectivity in autosomal dominant and late-onset Alzheimer disease.

PubMed

Thomas, Jewell B; Brier, Matthew R; Bateman, Randall J; Snyder, Abraham Z; Benzinger, Tammie L; Xiong, Chengjie; Raichle, Marcus; Holtzman, David M; Sperling, Reisa A; Mayeux, Richard; Ghetti, Bernardino; Ringman, John M; Salloway, Stephen; McDade, Eric; Rossor, Martin N; Ourselin, Sebastien; Schofield, Peter R; Masters, Colin L; Martins, Ralph N; Weiner, Michael W; Thompson, Paul M; Fox, Nick C; Koeppe, Robert A; Jack, Clifford R; Mathis, Chester A; Oliver, Angela; Blazey, Tyler M; Moulder, Krista; Buckles, Virginia; Hornbeck, Russ; Chhatwal, Jasmeer; Schultz, Aaron P; Goate, Alison M; Fagan, Anne M; Cairns, Nigel J; Marcus, Daniel S; Morris, John C; Ances, Beau M

2014-09-01

Autosomal dominant Alzheimer disease (ADAD) is caused by rare genetic mutations in 3 specific genes in contrast to late-onset Alzheimer disease (LOAD), which has a more polygenetic risk profile. To assess the similarities and differences in functional connectivity changes owing to ADAD and LOAD. We analyzed functional connectivity in multiple brain resting state networks (RSNs) in a cross-sectional cohort of participants with ADAD (n = 79) and LOAD (n = 444), using resting-state functional connectivity magnetic resonance imaging at multiple international academic sites. For both types of AD, we quantified and compared functional connectivity changes in RSNs as a function of dementia severity measured by the Clinical Dementia Rating Scale. In ADAD, we qualitatively investigated functional connectivity changes with respect to estimated years from onset of symptoms within 5 RSNs. A decrease in functional connectivity with increasing Clinical Dementia Rating scores were similar for both LOAD and ADAD in multiple RSNs. Ordinal logistic regression models constructed in one type of Alzheimer disease accurately predicted clinical dementia rating scores in the other, further demonstrating the similarity of functional connectivity loss in each disease type. Among participants with ADAD, functional connectivity in multiple RSNs appeared qualitatively lower in asymptomatic mutation carriers near their anticipated age of symptom onset compared with asymptomatic mutation noncarriers. Resting-state functional connectivity magnetic resonance imaging changes with progressing AD severity are similar between ADAD and LOAD. Resting-state functional connectivity magnetic resonance imaging may be a useful end point for LOAD and ADAD therapy trials. Moreover, the disease process of ADAD may be an effective model for the LOAD disease process.

The autism brain imaging data exchange: towards a large-scale evaluation of the intrinsic brain architecture in autism.

PubMed

Di Martino, A; Yan, C-G; Li, Q; Denio, E; Castellanos, F X; Alaerts, K; Anderson, J S; Assaf, M; Bookheimer, S Y; Dapretto, M; Deen, B; Delmonte, S; Dinstein, I; Ertl-Wagner, B; Fair, D A; Gallagher, L; Kennedy, D P; Keown, C L; Keysers, C; Lainhart, J E; Lord, C; Luna, B; Menon, V; Minshew, N J; Monk, C S; Mueller, S; Müller, R-A; Nebel, M B; Nigg, J T; O'Hearn, K; Pelphrey, K A; Peltier, S J; Rudie, J D; Sunaert, S; Thioux, M; Tyszka, J M; Uddin, L Q; Verhoeven, J S; Wenderoth, N; Wiggins, J L; Mostofsky, S H; Milham, M P

2014-06-01

Autism spectrum disorders (ASDs) represent a formidable challenge for psychiatry and neuroscience because of their high prevalence, lifelong nature, complexity and substantial heterogeneity. Facing these obstacles requires large-scale multidisciplinary efforts. Although the field of genetics has pioneered data sharing for these reasons, neuroimaging had not kept pace. In response, we introduce the Autism Brain Imaging Data Exchange (ABIDE)-a grassroots consortium aggregating and openly sharing 1112 existing resting-state functional magnetic resonance imaging (R-fMRI) data sets with corresponding structural MRI and phenotypic information from 539 individuals with ASDs and 573 age-matched typical controls (TCs; 7-64 years) (http://fcon_1000.projects.nitrc.org/indi/abide/). Here, we present this resource and demonstrate its suitability for advancing knowledge of ASD neurobiology based on analyses of 360 male subjects with ASDs and 403 male age-matched TCs. We focused on whole-brain intrinsic functional connectivity and also survey a range of voxel-wise measures of intrinsic functional brain architecture. Whole-brain analyses reconciled seemingly disparate themes of both hypo- and hyperconnectivity in the ASD literature; both were detected, although hypoconnectivity dominated, particularly for corticocortical and interhemispheric functional connectivity. Exploratory analyses using an array of regional metrics of intrinsic brain function converged on common loci of dysfunction in ASDs (mid- and posterior insula and posterior cingulate cortex), and highlighted less commonly explored regions such as the thalamus. The survey of the ABIDE R-fMRI data sets provides unprecedented demonstrations of both replication and novel discovery. By pooling multiple international data sets, ABIDE is expected to accelerate the pace of discovery setting the stage for the next generation of ASD studies.

Evidence for tectonic, lithologic, and thermal controls on fracture system geometries in an andesitic high-temperature geothermal field

NASA Astrophysics Data System (ADS)

Massiot, Cécile; Nicol, Andrew; McNamara, David D.; Townend, John

2017-08-01

Analysis of fracture orientation, spacing, and thickness from acoustic borehole televiewer (BHTV) logs and cores in the andesite-hosted Rotokawa geothermal reservoir (New Zealand) highlights potential controls on the geometry of the fracture system. Cluster analysis of fracture orientations indicates four fracture sets. Probability distributions of fracture spacing and thickness measured on BHTV logs are estimated for each fracture set, using maximum likelihood estimations applied to truncated size distributions to account for sampling bias. Fracture spacing is dominantly lognormal, though two subordinate fracture sets have a power law spacing. This difference in spacing distributions may reflect the influence of the andesitic sequence stratification (lognormal) and tectonic faults (power law). Fracture thicknesses of 9-30 mm observed in BHTV logs, and 1-3 mm in cores, are interpreted to follow a power law. Fractures in thin sections (˜5 μm thick) do not fit this power law distribution, which, together with their orientation, reflect a change of controls on fracture thickness from uniform (such as thermal) controls at thin section scale to anisotropic (tectonic) at core and BHTV scales of observation. However, the ˜5% volumetric percentage of fractures within the rock at all three scales suggests a self-similar behavior in 3-D. Power law thickness distributions potentially associated with power law fluid flow rates, and increased connectivity where fracture sets intersect, may cause the large permeability variations that occur at hundred meter scales in the reservoir. The described fracture geometries can be incorporated into fracture and flow models to explore the roles of fracture connectivity, stress, and mineral precipitation/dissolution on permeability in such andesite-hosted geothermal systems.

A supplementary functional connectivity microstate attached to the default mode network in depression revealed by resting-state magnetoencephalography.

PubMed

Zhang, Siqi; Tian, Shui; Chattun, Mohammad Ridwan; Tang, Hao; Yan, Rui; Bi, Kun; Yao, Zhijian; Lu, Qing

2018-04-20

Default mode network (DMN) has discernable involvement in the representation of negative, self-referential information in depression. Both increased and decreased resting-state functional connectivity between the anterior and posterior DMN have been observed in depression. These conflicting connectivity differences necessitated further exploration of the resting-state DMN dysfunction in depression. Hence, we investigated the time-varying dynamic interactions within the DMN via functional connectivity microstates in a sub-second level. 25 patients with depression and 25 matched healthy controls were enrolled in the MEG analysis. Spherical K-means algorithms embedded within an iterative optimization frame were applied to sliding windowed correlation matrices, resulting in sub-second alternations of two functional connectivity microstates for groups and highlighting the presence of functional variability. In the power dominant state, depressed patients showed a transient decreased pattern that reflected inter/intra-subnetwork deregulation. A supplementary negatively correlated state simultaneously presented with increased connectivity between the ventromedial prefrontal cortex (vmPFC) and the posterior cingulate cortex (PCC), two core nodes for the anterior and posterior DMN respectively. Additionally, depressed patients stayed longer in the supplementary microstate compared to healthy controls. During the time spent in the supplementary microstate, an attempt to compensate for the aberrant effect of vmPFC on PCC across DMN subnetworks was possibly made to balance the self-related processes disturbed by the dominant pattern. The functional compensation mechanism of the supplementary microstate attached to the dominant disrupted one provided a possible explanation to the existing inconsistent findings between the anterior and posterior DMN in depression. Copyright © 2018 Elsevier Inc. All rights reserved.

Mean Platelet Volume as an Indicator of Platelet Rejuvenation Following Bone Marrow Transplantation.

DTIC Science & Technology

1986-07-01

al., 1972 Family R ACD volume D D Murphy et al., 1972 Connective Tissue Disorders Ehlers - Danlos Syndrome diameter N I Estes, 1968 Marlan Syndrome ...autosomal dominant), Maran syndrome (autosomal dominant), Mucopolysaccharidosis syndrome (sex-linked), Ehlers - Danlos syndrome (autosomal dominant...individuals with hyperdestructive syndromes (Paulus, 1975). If macrothrombocytosis in hyperdestruction is due only to the young age of the circulating

Mixed Model Methods for Genomic Prediction and Variance Component Estimation of Additive and Dominance Effects Using SNP Markers

PubMed Central

Da, Yang; Wang, Chunkao; Wang, Shengwen; Hu, Guo

2014-01-01

We established a genomic model of quantitative trait with genomic additive and dominance relationships that parallels the traditional quantitative genetics model, which partitions a genotypic value as breeding value plus dominance deviation and calculates additive and dominance relationships using pedigree information. Based on this genomic model, two sets of computationally complementary but mathematically identical mixed model methods were developed for genomic best linear unbiased prediction (GBLUP) and genomic restricted maximum likelihood estimation (GREML) of additive and dominance effects using SNP markers. These two sets are referred to as the CE and QM sets, where the CE set was designed for large numbers of markers and the QM set was designed for large numbers of individuals. GBLUP and associated accuracy formulations for individuals in training and validation data sets were derived for breeding values, dominance deviations and genotypic values. Simulation study showed that GREML and GBLUP generally were able to capture small additive and dominance effects that each accounted for 0.00005–0.0003 of the phenotypic variance and GREML was able to differentiate true additive and dominance heritability levels. GBLUP of the total genetic value as the summation of additive and dominance effects had higher prediction accuracy than either additive or dominance GBLUP, causal variants had the highest accuracy of GREML and GBLUP, and predicted accuracies were in agreement with observed accuracies. Genomic additive and dominance relationship matrices using SNP markers were consistent with theoretical expectations. The GREML and GBLUP methods can be an effective tool for assessing the type and magnitude of genetic effects affecting a phenotype and for predicting the total genetic value at the whole genome level. PMID:24498162

Mixed model methods for genomic prediction and variance component estimation of additive and dominance effects using SNP markers.

PubMed

Da, Yang; Wang, Chunkao; Wang, Shengwen; Hu, Guo

2014-01-01

We established a genomic model of quantitative trait with genomic additive and dominance relationships that parallels the traditional quantitative genetics model, which partitions a genotypic value as breeding value plus dominance deviation and calculates additive and dominance relationships using pedigree information. Based on this genomic model, two sets of computationally complementary but mathematically identical mixed model methods were developed for genomic best linear unbiased prediction (GBLUP) and genomic restricted maximum likelihood estimation (GREML) of additive and dominance effects using SNP markers. These two sets are referred to as the CE and QM sets, where the CE set was designed for large numbers of markers and the QM set was designed for large numbers of individuals. GBLUP and associated accuracy formulations for individuals in training and validation data sets were derived for breeding values, dominance deviations and genotypic values. Simulation study showed that GREML and GBLUP generally were able to capture small additive and dominance effects that each accounted for 0.00005-0.0003 of the phenotypic variance and GREML was able to differentiate true additive and dominance heritability levels. GBLUP of the total genetic value as the summation of additive and dominance effects had higher prediction accuracy than either additive or dominance GBLUP, causal variants had the highest accuracy of GREML and GBLUP, and predicted accuracies were in agreement with observed accuracies. Genomic additive and dominance relationship matrices using SNP markers were consistent with theoretical expectations. The GREML and GBLUP methods can be an effective tool for assessing the type and magnitude of genetic effects affecting a phenotype and for predicting the total genetic value at the whole genome level.

Leaf traits within communities: context may affect the mapping of traits to function.

PubMed

Funk, Jennifer L; Cornwell, William K

2013-09-01

The leaf economics spectrum (LES) has revolutionized the way many ecologists think about quantifying plant ecological trade-offs. In particular, the LES has connected a clear functional trade-off (long-lived leaves with slow carbon capture vs. short-lived leaves with fast carbon capture) to a handful of easily measured leaf traits. Building on this work, community ecologists are now able to quickly assess species carbon-capture strategies, which may have implications for community-level patterns such as competition or succession. However, there are a number of steps in this logic that require careful examination, and a potential danger arises when interpreting leaf-trait variation among species within communities where trait relationships are weak. Using data from 22 diverse communities, we show that relationships among three common functional traits (photosynthetic rate, leaf nitrogen concentration per mass, leaf mass per area) are weak in communities with low variation in leaf life span (LLS), especially communities dominated by herbaceous or deciduous woody species. However, globally there are few LLS data sets for communities dominated by herbaceous or deciduous species, and more data are needed to confirm this pattern. The context-dependent nature of trait relationships at the community level suggests that leaf-trait variation within communities, especially those dominated by herbaceous and deciduous woody species, should be interpreted with caution.

Dominant partition method. [based on a wave function formalism

NASA Technical Reports Server (NTRS)

Dixon, R. M.; Redish, E. F.

1979-01-01

By use of the L'Huillier, Redish, and Tandy (LRT) wave function formalism, a partially connected method, the dominant partition method (DPM) is developed for obtaining few body reductions of the many body problem in the LRT and Bencze, Redish, and Sloan (BRS) formalisms. The DPM maps the many body problem to a fewer body one by using the criterion that the truncated formalism must be such that consistency with the full Schroedinger equation is preserved. The DPM is based on a class of new forms for the irreducible cluster potential, which is introduced in the LRT formalism. Connectivity is maintained with respect to all partitions containing a given partition, which is referred to as the dominant partition. Degrees of freedom corresponding to the breakup of one or more of the clusters of the dominant partition are treated in a disconnected manner. This approach for simplifying the complicated BRS equations is appropriate for physical problems where a few body reaction mechanism prevails.

Resting-State Functional Connectivity Emerges from Structurally and Dynamically Shaped Slow Linear Fluctuations

PubMed Central

Deco, Gustavo; Mantini, Dante; Romani, Gian Luca; Hagmann, Patric; Corbetta, Maurizio

2013-01-01

Brain fluctuations at rest are not random but are structured in spatial patterns of correlated activity across different brain areas. The question of how resting-state functional connectivity (FC) emerges from the brain's anatomical connections has motivated several experimental and computational studies to understand structure–function relationships. However, the mechanistic origin of resting state is obscured by large-scale models' complexity, and a close structure–function relation is still an open problem. Thus, a realistic but simple enough description of relevant brain dynamics is needed. Here, we derived a dynamic mean field model that consistently summarizes the realistic dynamics of a detailed spiking and conductance-based synaptic large-scale network, in which connectivity is constrained by diffusion imaging data from human subjects. The dynamic mean field approximates the ensemble dynamics, whose temporal evolution is dominated by the longest time scale of the system. With this reduction, we demonstrated that FC emerges as structured linear fluctuations around a stable low firing activity state close to destabilization. Moreover, the model can be further and crucially simplified into a set of motion equations for statistical moments, providing a direct analytical link between anatomical structure, neural network dynamics, and FC. Our study suggests that FC arises from noise propagation and dynamical slowing down of fluctuations in an anatomically constrained dynamical system. Altogether, the reduction from spiking models to statistical moments presented here provides a new framework to explicitly understand the building up of FC through neuronal dynamics underpinned by anatomical connections and to drive hypotheses in task-evoked studies and for clinical applications. PMID:23825427

Resting-state functional connectivity emerges from structurally and dynamically shaped slow linear fluctuations.

PubMed

Deco, Gustavo; Ponce-Alvarez, Adrián; Mantini, Dante; Romani, Gian Luca; Hagmann, Patric; Corbetta, Maurizio

2013-07-03

Brain fluctuations at rest are not random but are structured in spatial patterns of correlated activity across different brain areas. The question of how resting-state functional connectivity (FC) emerges from the brain's anatomical connections has motivated several experimental and computational studies to understand structure-function relationships. However, the mechanistic origin of resting state is obscured by large-scale models' complexity, and a close structure-function relation is still an open problem. Thus, a realistic but simple enough description of relevant brain dynamics is needed. Here, we derived a dynamic mean field model that consistently summarizes the realistic dynamics of a detailed spiking and conductance-based synaptic large-scale network, in which connectivity is constrained by diffusion imaging data from human subjects. The dynamic mean field approximates the ensemble dynamics, whose temporal evolution is dominated by the longest time scale of the system. With this reduction, we demonstrated that FC emerges as structured linear fluctuations around a stable low firing activity state close to destabilization. Moreover, the model can be further and crucially simplified into a set of motion equations for statistical moments, providing a direct analytical link between anatomical structure, neural network dynamics, and FC. Our study suggests that FC arises from noise propagation and dynamical slowing down of fluctuations in an anatomically constrained dynamical system. Altogether, the reduction from spiking models to statistical moments presented here provides a new framework to explicitly understand the building up of FC through neuronal dynamics underpinned by anatomical connections and to drive hypotheses in task-evoked studies and for clinical applications.

Connectivity Among Salt Marsh Subhabitats: Residency and Movements of the Mummichog (Fundulus heteroclitus)

EPA Science Inventory

We examined connectivity among marsh subhabitats to determine the structural limits and important components of a polyhaline salt marsh by studying the patterns of abundance, residency, and movement of a numerically and ecologically dominant nektonic fish (mummichog, Fundulus het...

Frequency-response mismatch effects in Johnson noise thermometry

NASA Astrophysics Data System (ADS)

White, D. R.; Qu, J.-F.

2018-02-01

Johnson noise thermometry is of considerable interest at present due to the planned redefinition of the kelvin in 2019, and several determinations of the Boltzmann constant have recently been published in support of the redefinition. To determine the Boltzmann constant by noise thermometry, the thermal noise from a sensing resistor at the triple point of water is compared to a pseudo-random noise with a calculable power spectral density traceable to quantum electrical standards. In all the measurements to date, the two dominant sources of measurement uncertainty are strongly influenced by a single factor: the frequency-response mismatch between the sets of leads connecting the thermometer to the two noise sources. In the most recent determination at the National Institute of Metrology, China, substantial changes were made to the connecting leads to reduce the mismatch effects. The aims of this paper are, firstly, to describe and explain the rationale for the changes, and secondly, to better understand the effects of the least-squares fits and the bias-variance compromise in the analysis of measurements affected by the mismatch effects. While significant improvements can be made to the connecting leads to lessen the effects of the frequency-response mismatch, the efforts are unlikely to be rewarded by a significant increase in bandwidth or a significant reduction in uncertainty.

Utilizing Maximal Independent Sets as Dominating Sets in Scale-Free Networks

NASA Astrophysics Data System (ADS)

Derzsy, N.; Molnar, F., Jr.; Szymanski, B. K.; Korniss, G.

Dominating sets provide key solution to various critical problems in networked systems, such as detecting, monitoring, or controlling the behavior of nodes. Motivated by graph theory literature [Erdos, Israel J. Math. 4, 233 (1966)], we studied maximal independent sets (MIS) as dominating sets in scale-free networks. We investigated the scaling behavior of the size of MIS in artificial scale-free networks with respect to multiple topological properties (size, average degree, power-law exponent, assortativity), evaluated its resilience to network damage resulting from random failure or targeted attack [Molnar et al., Sci. Rep. 5, 8321 (2015)], and compared its efficiency to previously proposed dominating set selection strategies. We showed that, despite its small set size, MIS provides very high resilience against network damage. Using extensive numerical analysis on both synthetic and real-world (social, biological, technological) network samples, we demonstrate that our method effectively satisfies four essential requirements of dominating sets for their practical applicability on large-scale real-world systems: 1.) small set size, 2.) minimal network information required for their construction scheme, 3.) fast and easy computational implementation, and 4.) resiliency to network damage. Supported by DARPA, DTRA, and NSF.

A method to assess longitudinal riverine connectivity in tropical streams dominated by migratory biota

USGS Publications Warehouse

Crook, K.E.; Pringle, C.M.; Freeman, Mary C.

2009-01-01

1. One way in which dams affect ecosystem function is by altering the distribution and abundance of aquatic species. 2. Previous studies indicate that migratory shrimps have significant effects on ecosystem processes in Puerto Rican streams, but are vulnerable to impediments to upstream or downstream passage, such as dams and associated water intakes where stream water is withdrawn for human water supplies. Ecological effects of dams and water withdrawals from streams depend on spatial context and temporal variability of flow in relation to the amount of water withdrawn. 3. This paper presents a conceptual model for estimating the probability that an individual shrimp is able to migrate from a stream's headwaters to the estuary as a larva, and then return to the headwaters as a juvenile, given a set of dams and water withdrawals in the stream network. The model is applied to flow and withdrawal data for a set of dams and water withdrawals in the Caribbean National Forest (CNF) in Puerto Rico. 4. The index of longitudinal riverine connectivity (ILRC), is used to classify 17 water intakes in streams draining the CNF as having low, moderate, or high connectivity in terms of shrimp migration in both directions. An in-depth comparison of two streams showed that the stream characterized by higher water withdrawal had low connectivity, even during wet periods. Severity of effects is illustrated by a drought year, where the most downstream intake caused 100% larval shrimp mortality 78% of the year. 5. The ranking system provided by the index can be used as a tool for conservation ecologists and water resource managers to evaluate the relative vulnerability of migratory biota in streams, across different scales (reach-network), to seasonally low flows and extended drought. This information can be used to help evaluate the environmental tradeoffs of future water withdrawals. ?? 2008 John Wiley & Sons, Ltd.

Emerging trends in evolving networks: Recent behaviour dominant and non-dominant model

NASA Astrophysics Data System (ADS)

Abbas, Khushnood; Shang, Mingsheng; Luo, Xin; Abbasi, Alireza

2017-10-01

Novel phenomenon receives similar attention as popular one. Therefore predicting novelty is as important as popularity. Emergence is the side effect of competition and ageing in evolving systems. Recent behaviour or recent link gain in networks plays an important role in emergence. We exploited this wisdom and came up with two models considering different scenarios and systems. Where recent behaviour dominates over total behaviour (total link gain) in the first one, and recent behaviour is as important as total behaviour for future link gain in the second one. It supposes that random walker walks on a network and can jump to any node, the probability of jumping or making a connection to other node is based on which node is recently more active or receiving more links. In our assumption, the random walker can also jump to the node which is already popular but recently not popular. We are able to predict emerging nodes which are generally suppressed under preferential attachment effect. To show the performance of our model we have conducted experiments on four real data sets namely, MovieLens, Netflix, Facebook and Arxiv High Energy Physics paper citation. For testing our model we used four information retrieval indices namely Precision, Novelty, Area Under Receiving Operating Characteristic (AUC) and Kendal's rank correlation coefficient. We have used four benchmark models for validating our proposed models. Although our model does not perform better in all the cases but, it has theoretical significance in working better for recent behaviour dominated systems.

An ILP based memetic algorithm for finding minimum positive influence dominating sets in social networks

NASA Astrophysics Data System (ADS)

Lin, Geng; Guan, Jian; Feng, Huibin

2018-06-01

The positive influence dominating set problem is a variant of the minimum dominating set problem, and has lots of applications in social networks. It is NP-hard, and receives more and more attention. Various methods have been proposed to solve the positive influence dominating set problem. However, most of the existing work focused on greedy algorithms, and the solution quality needs to be improved. In this paper, we formulate the minimum positive influence dominating set problem as an integer linear programming (ILP), and propose an ILP based memetic algorithm (ILPMA) for solving the problem. The ILPMA integrates a greedy randomized adaptive construction procedure, a crossover operator, a repair operator, and a tabu search procedure. The performance of ILPMA is validated on nine real-world social networks with nodes up to 36,692. The results show that ILPMA significantly improves the solution quality, and is robust.

Increased functional connectivity between cortical hand areas and praxis network associated with training-related improvements in non-dominant hand precision drawing.

PubMed

Philip, Benjamin A; Frey, Scott H

2016-07-01

Chronic forced use of the non-dominant left hand yields substantial improvements in the precision and quality of writing and drawing. These changes may arise from increased access by the non-dominant (right) hemisphere to dominant (left) hemisphere mechanisms specialized for end-point precision control. To evaluate this prediction, 22 healthy right-handed adults underwent resting state functional connectivity (FC) MRI scans before and after 10 days of training on a left hand precision drawing task. 89% of participants significantly improved left hand speed, accuracy, and smoothness. Smoothness gains were specific to the trained left hand and persistent: 6 months after training, 71% of participants exhibited above-baseline movement smoothness. Contrary to expectations, we found no evidence of increased FC between right and left hemisphere hand areas. Instead, training-related improvements in left hand movement smoothness were associated with increased FC between both sensorimotor hand areas and a left-lateralized parieto-prefrontal network implicated in manual praxis. By contrast, skill retention at 6 months was predicted by changes including decreased FC between the representation of the trained left hand and bilateral sensorimotor, parietal, and premotor cortices, possibly reflecting consolidation and a disengagement of early learning processes. These data indicate that modest amounts of training (<200min total) can induce substantial, persistent improvements the precision and quality of non-dominant hand control in healthy adults, supported by strengthened connectivity between bilateral sensorimotor hand areas and a left-lateralized parieto-prefrontal praxis network. Copyright © 2016 Elsevier Ltd. All rights reserved.

Discrete kinetic models from funneled energy landscape simulations.

PubMed

Schafer, Nicholas P; Hoffman, Ryan M B; Burger, Anat; Craig, Patricio O; Komives, Elizabeth A; Wolynes, Peter G

2012-01-01

A general method for facilitating the interpretation of computer simulations of protein folding with minimally frustrated energy landscapes is detailed and applied to a designed ankyrin repeat protein (4ANK). In the method, groups of residues are assigned to foldons and these foldons are used to map the conformational space of the protein onto a set of discrete macrobasins. The free energies of the individual macrobasins are then calculated, informing practical kinetic analysis. Two simple assumptions about the universality of the rate for downhill transitions between macrobasins and the natural local connectivity between macrobasins lead to a scheme for predicting overall folding and unfolding rates, generating chevron plots under varying thermodynamic conditions, and inferring dominant kinetic folding pathways. To illustrate the approach, free energies of macrobasins were calculated from biased simulations of a non-additive structure-based model using two structurally motivated foldon definitions at the full and half ankyrin repeat resolutions. The calculated chevrons have features consistent with those measured in stopped flow chemical denaturation experiments. The dominant inferred folding pathway has an "inside-out", nucleation-propagation like character.

Identifying pathogenic processes by integrating microarray data with prior knowledge

PubMed Central

2014-01-01

Background It is of great importance to identify molecular processes and pathways that are involved in disease etiology. Although there has been an extensive use of various high-throughput methods for this task, pathogenic pathways are still not completely understood. Often the set of genes or proteins identified as altered in genome-wide screens show a poor overlap with canonical disease pathways. These findings are difficult to interpret, yet crucial in order to improve the understanding of the molecular processes underlying the disease progression. We present a novel method for identifying groups of connected molecules from a set of differentially expressed genes. These groups represent functional modules sharing common cellular function and involve signaling and regulatory events. Specifically, our method makes use of Bayesian statistics to identify groups of co-regulated genes based on the microarray data, where external information about molecular interactions and connections are used as priors in the group assignments. Markov chain Monte Carlo sampling is used to search for the most reliable grouping. Results Simulation results showed that the method improved the ability of identifying correct groups compared to traditional clustering, especially for small sample sizes. Applied to a microarray heart failure dataset the method found one large cluster with several genes important for the structure of the extracellular matrix and a smaller group with many genes involved in carbohydrate metabolism. The method was also applied to a microarray dataset on melanoma cancer patients with or without metastasis, where the main cluster was dominated by genes related to keratinocyte differentiation. Conclusion Our method found clusters overlapping with known pathogenic processes, but also pointed to new connections extending beyond the classical pathways. PMID:24758699

Effects of hydrologic connectivity and environmental nariables on nekton assemblage in a coastal marsh system

USGS Publications Warehouse

Kang, Sung-Ryong; King, Sammy L.

2013-01-01

Hydrologic connectivity and environmental variation can influence nekton assemblages in coastal ecosystems. We evaluated the effects of hydrologic connectivity (permanently connected pond: PCP; temporary connected pond: TCP), salinity, vegetation coverage, water depth and other environmental variables on seasonal nekton assemblages in freshwater, brackish, and saline marshes of the Chenier Plain, Louisiana, USA. We hypothesize that 1) nekton assemblages in PCPs have higher metrics (density, biomass, assemblage similarity) than TCPs within all marsh types and 2) no nekton species would be dominant across all marsh types. In throw traps, freshwater PCPs in Fall (36.0 ± 1.90) and Winter 2009 (43.2 ± 22.36) supported greater biomass than freshwater TCPs (Fall 2009: 9.1 ± 4.65; Winter 2009: 8.3 ± 3.42). In minnow traps, saline TCPs (5.9 ± 0.85) in Spring 2009 had higher catch per unit effort than saline PCPs (0.7 ± 0.67). Our data only partially support our first hypothesis as freshwater marsh PCPs had greater assemblage similarity than TCPs. As predicted by our second hypothesis, no nekton species dominated across all marsh types. Nekton assemblages were structured by individual species responses to the salinity gradient as well as pond habitat attributes (submerged aquatic vegetation coverage, dissolved oxygen, hydrologic connectivity).

Contributions of structural connectivity and cerebrovascular parameters to functional magnetic resonance imaging signals in mice at rest and during sensory paw stimulation.

PubMed

Schroeter, Aileen; Grandjean, Joanes; Schlegel, Felix; Saab, Bechara J; Rudin, Markus

2017-07-01

Previously, we reported widespread bilateral increases in stimulus-evoked functional magnetic resonance imaging signals in mouse brain to unilateral sensory paw stimulation. We attributed the pattern to arousal-related cardiovascular changes overruling cerebral autoregulation thereby masking specific signal changes elicited by local neuronal activity. To rule out the possibility that interhemispheric neuronal communication might contribute to bilateral functional magnetic resonance imaging responses, we compared stimulus-evoked functional magnetic resonance imaging responses to unilateral hindpaw stimulation in acallosal I/LnJ, C57BL/6, and BALB/c mice. We found bilateral blood-oxygenation-level dependent signal changes in all three strains, ruling out a dominant contribution of transcallosal communication as reason for bilaterality. Analysis of functional connectivity derived from resting-state functional magnetic resonance imaging, revealed that bilateral cortical functional connectivity is largely abolished in I/LnJ animals. Cortical functional connectivity in all strains correlated with structural connectivity in corpus callosum as revealed by diffusion tensor imaging. Given the profound influence of systemic hemodynamics on stimulus-evoked functional magnetic resonance imaging outcomes, we evaluated whether functional connectivity data might be affected by cerebrovascular parameters, i.e. baseline cerebral blood volume, vascular reactivity, and reserve. We found that effects of cerebral hemodynamics on functional connectivity are largely outweighed by dominating contributions of structural connectivity. In contrast, contributions of transcallosal interhemispheric communication to the occurrence of ipsilateral functional magnetic resonance imaging response of equal amplitude to unilateral stimuli seem negligible.

High reduction transaxle for electric vehicle

DOEpatents

Kalns, Ilmars

1987-01-01

A drivetrain (12) includes a transaxle assembly (16) for driving ground engaging wheels of a land vehicle powered by an AC motor. The transaxle includes a ratio change section having planetary gear sets (24, 26) and brake assemblies (28, 30). Sun gears (60, 62) of the gear sets are directly and continuously connected to an input drive shaft (38) driven by the motor. A first drive (78a) directly and continuously connects a planetary gear carrier (78) of gear sets (24) with a ring gear (68) of gear set (26). A second drive (80a) directly and continuously connects a planetary gear carrier (80) of gear set (26) with a sun gear (64) of a final speed reduction gear set (34) having a planetary gear carrier directly and continuously connected to a differential (22). Brakes (28, 30) are selectively engageable to respectively ground a ring gear 66 of gear set 24 and ring gear 68 of gear set 26.

Connective Processing by Bilingual Children and Monolinguals with Specific Language Impairment: Distinct Profiles

ERIC Educational Resources Information Center

Mak, Willem M.; Tribushinina, Elena; Lomako, Julia; Gagarina, Natalia; Abrosova, Ekaterina; Sanders, Ted

2017-01-01

Production studies show that both Russian-speaking children with specific language impairment (SLI) and bilingual children for whom Russian is a non-dominant language have difficulty distinguishing between the near-synonymous connectives "i" "and" and "a" "and/but." "I" is a preferred connective…

Factors that Influence Comprehension of Connectives among Language Minority Children from Spanish-Speaking Backgrounds

ERIC Educational Resources Information Center

Crosson, Amy C.; Lesaux, Nonie K.; Martiniello, Maria

2008-01-01

This study explores factors influencing the degree to which language minority (LM) children from Spanish-dominant homes understand how connectives, such as "in contrast" and "because", signal relationships between text propositions. Standardized tasks of vocabulary, listening comprehension, word reading, and a researcher-designed text cohesion…

Integrative Analysis of Disease Signatures Shows Inflammation Disrupts Juvenile Experience-Dependent Cortical Plasticity

PubMed Central

Smith, Milo R.; Burman, Poromendro

2016-01-01

Throughout childhood and adolescence, periods of heightened neuroplasticity are critical for the development of healthy brain function and behavior. Given the high prevalence of neurodevelopmental disorders, such as autism, identifying disruptors of developmental plasticity represents an essential step for developing strategies for prevention and intervention. Applying a novel computational approach that systematically assessed connections between 436 transcriptional signatures of disease and multiple signatures of neuroplasticity, we identified inflammation as a common pathological process central to a diverse set of diseases predicted to dysregulate plasticity signatures. We tested the hypothesis that inflammation disrupts developmental cortical plasticity in vivo using the mouse ocular dominance model of experience-dependent plasticity in primary visual cortex. We found that the administration of systemic lipopolysaccharide suppressed plasticity during juvenile critical period with accompanying transcriptional changes in a particular set of molecular regulators within primary visual cortex. These findings suggest that inflammation may have unrecognized adverse consequences on the postnatal developmental trajectory and indicate that treating inflammation may reduce the burden of neurodevelopmental disorders. PMID:28101530

[Machismo, made in Mexico? Social implications of the masculine hegemony in Mexico].

PubMed

Ortiz-Ortega, Adriana; Rivas-Zivy, Marta

2006-01-01

Hegemonic masculinity may be considered a public health problem in that it promotes aggressive behavior, violence towards men and women, and self-injury. "Being a man" within such a pattern implies stress, tension and anxiety to prove one's own masculinity. This article proposes that it is necessary to understand how dominant masculinity is individually and socially connected with the exercise of power over women and its implications in legislation and rights, to go beyond it. This text reviews these connections both through interviews with men and through examining how literature on masculinities presents the rarely discussed connections among power, law, legislation and dominant notions of masculinity. It explores the notion of power present both in literature and in men's perceptions, as a way to understand which perceptions of authority are culturally and socially legitimated by men. It is concluded that masculinities are in a process of transformation in Mexico, but that important vacuums persist which arrest the eradication of dominant masculinity. The analysis is based on a bibliographic revision, together with group and individual interviews with men. Results show how in the men's perceptions and reflections on the exercise of power, there persists a lack of criticism.

The Miocene Sommières basin, SE France: Bioclastic carbonates in a tide-dominated depositional system

NASA Astrophysics Data System (ADS)

Reynaud, Jean-Yves; James, Noël P.

2012-12-01

The Miocene Sommières Basin in SE France is a semi-enclosed depression that was connected to the Mediterranean Sea by a flooded paleo-incised valley and then filled by a suite of sediments comprising carbonate grains coming from temperate factories that were largely deposited in tidal-dominated paleoenvironments. The strata are partitioned into two sequences that reflect repeated flooding of the incised valley system, one of several similar situations in this region of France. The carbonate grains are mostly bioclasts, namely from barnacles, bryozoans, coralline algae (encrusting, branching, and rhodoliths), echinoids, and benthic foraminifers (large and small) with ostracods, sponge spicules and planktic foraminifers prominent in muddy facies. Particles were produced by shallow water carbonate factories on hard substrates (valley walls in particular), associated with subaqueous dunes, and in deeper water basinal settings. Each depositional sequence is underlain by an eroded and bored hard surface that is progressively overlain by TST subaqueous tidal dunes or storm deposits that grade up, in one case, into HST marls (the HST of the upper sequence has been removed by erosion). The lower sequence is ebb tide dominated whereas the upper sequence is flood tide dominated. The succession is interpreted to represent a TST whose tidal currents were focused by the narrow valley and a HST that reflected flooding of the overbanks. This stratigraphic and depositional motif is comparable to that in other spatially separated Neogene paleovalleys that are filled with tide-dominated clastic carbonates in the region. Together with other recently documented similar systems, these limestones constitute an important new group of carbonate sand bodies in the carbonate depositional realm.

Enhancing Network Communication in NPSNET-V Virtual Environments Using XML-Described Dynamic Behavior (DBP) Protocols

DTIC Science & Technology

2001-09-01

testing is performed between two machines connected by either a 100 Mbps Ethernet connection or a 56K modem connection. This testing is performed...and defined as follows: • The available bandwidth is set at two different levels (Ethernet 100 Mbps and 56K modem ). 32 • The packet size is set... modem connection. These two connections represent the target 100 Mbps high end and 56k bps low end of anticipated client connections in web-based

Generalized reproduction numbers and the prediction of patterns in waterborne disease.

PubMed

Gatto, Marino; Mari, Lorenzo; Bertuzzo, Enrico; Casagrandi, Renato; Righetto, Lorenzo; Rodriguez-Iturbe, Ignacio; Rinaldo, Andrea

2012-11-27

Understanding, predicting, and controlling outbreaks of waterborne diseases are crucial goals of public health policies, but pose challenging problems because infection patterns are influenced by spatial structure and temporal asynchrony. Although explicit spatial modeling is made possible by widespread data mapping of hydrology, transportation infrastructure, population distribution, and sanitation, the precise condition under which a waterborne disease epidemic can start in a spatially explicit setting is still lacking. Here we show that the requirement that all the local reproduction numbers R0 be larger than unity is neither necessary nor sufficient for outbreaks to occur when local settlements are connected by networks of primary and secondary infection mechanisms. To determine onset conditions, we derive general analytical expressions for a reproduction matrix G0, explicitly accounting for spatial distributions of human settlements and pathogen transmission via hydrological and human mobility networks. At disease onset, a generalized reproduction number Λ0 (the dominant eigenvalue of G0) must be larger than unity. We also show that geographical outbreak patterns in complex environments are linked to the dominant eigenvector and to spectral properties of G0. Tests against data and computations for the 2010 Haiti and 2000 KwaZulu-Natal cholera outbreaks, as well as against computations for metapopulation networks, demonstrate that eigenvectors of G0 provide a synthetic and effective tool for predicting the disease course in space and time. Networked connectivity models, describing the interplay between hydrology, epidemiology, and social behavior sustaining human mobility, thus prove to be key tools for emergency management of waterborne infections.

Psychology of Working Narratives of STEM Career Exploration for Non-Dominant Youth

ERIC Educational Resources Information Center

Mark, Sheron L.

2016-01-01

Science, technology, engineering, and mathematics (STEM) is a domain of knowledge, skills, and practices that is pervasive and of critical importance in our highly technological, rapidly advancing, and increasingly connected world; however, non-dominant youth, namely from non-White, lower-income, non-English-speaking, and immigrant backgrounds,…

Preconstructing Suspicion and Recasting Masculinity in Preschool Settings

ERIC Educational Resources Information Center

Pruit, John C.

2014-01-01

Although there is literature explaining how female ethnographers negotiate male-dominated research settings, there is a lack of literature explaining how male ethnographers negotiate female-dominated settings. It is, more or less, taken for granted the research settings males choose will be suitable for them. The field of early childhood…

A wire length minimization approach to ocular dominance patterns in mammalian visual cortex

NASA Astrophysics Data System (ADS)

Chklovskii, Dmitri B.; Koulakov, Alexei A.

2000-09-01

The primary visual area (V1) of the mammalian brain is a thin sheet of neurons. Because each neuron is dominated by either right or left eye one can treat V1 as a binary mixture of neurons. The spatial arrangement of neurons dominated by different eyes is known as the ocular dominance (OD) pattern. We propose a theory for OD patterns based on the premise that they are evolutionary adaptations to minimize the length of intra-cortical connections. Thus, the existing OD patterns are obtained by solving a wire length minimization problem. We divide all the neurons into two classes: right- and left-eye dominated. We find that if the number of connections of each neuron with the neurons of the same class differs from that with the other class, the segregation of neurons into monocular regions indeed reduces the wire length. The shape of the regions depends on the relative number of neurons in the two classes. If both classes are equally represented we find that the optimal OD pattern consists of alternating stripes. If one class is less numerous than the other, the optimal OD pattern consists of patches of the underrepresented (ipsilateral) eye dominated neurons surrounded by the neurons of the other class. We predict the transition from stripes to patches when the fraction of neurons dominated by the ipsilateral eye is about 40%. This prediction agrees with the data in macaque and Cebus monkeys. Our theory can be applied to other binary cortical systems.

Electrostatic generator/motor having rotors of varying thickness and a central stator electrically connected together into two groups

DOEpatents

Post, Richard F.

2010-11-16

A sub-module consists of a set of two outer sets of stationary fan-blade-shaped sectors. These outer sectors include conductive material and are maintained at ground potential in several examples. Located midway between them is a set of stationary sector plates with each plate being electrically insulated from the others. An example provides that the inner sector plates are connected together alternately, forming two groups of parallel-connected condensers that are then separately connected, through high charging circuit resistances, to a source of DC potential with respect to ground, with an additional connecting lead being provided for each group to connect their output as an AC output to a load. These same leads can he used, when connected to a driver circuit, to produce motor action.

Reduced Language Connectivity in Pediatric Epilepsy

PubMed Central

Leigh N., Sepeta; Louise J., Croft; Lauren A., Zimmaro; Elizabeth S., Duke; Virginia K., Terwilliger; Benjamin E., Yerys; Xiaozhen., You; Chandan J., Vaidya; William D., Gaillard; Madison M., Berl

2014-01-01

Objective Functional connectivity (FC) among language regions is decreased in adults with epilepsy compared to controls, but less is known about FC in children with epilepsy. We sought to determine if language FC is reduced in pediatric epilepsy, and examined clinical factors that associate with language FC in this population. Methods We assessed FC during an age-adjusted language task in children with left-hemisphere focal epilepsy (n=19) compared to controls (n=19). Time series data were extracted for three left ROIs and their right homologues: inferior frontal gyrus (IFG), middle frontal gyrus (MFG), and Wernicke's area (WA) using SPM8. Associations between FC and factors such as cognitive performance, language dominance, and epilepsy duration were assessed. Results Children with epilepsy showed decreased interhemispheric connectivity compared to controls, particularly between core left language regions (IFG, WA) and their right hemisphere homologues, as well as decreased intrahemispheric right frontal FC. Increased intrahemispheric FC between left IFG and left WA was a positive predictor of language skills overall, and naming ability in particular. FC of language areas was not affected by language dominance, as the effects remained when only examining study participants with left language dominance. Overall FC did not differ according to duration of epilepsy or age of onset. Significance FC during a language task is reduced in children, similar to findings in adults. In specific, children with left focal epilepsy demonstrated decreased interhemispheric FC in temporal and frontal language connections and decreased intrahemispheric right frontal FC. These differences were present near the onset of epilepsy. Greater FC between left language centers is related to better language ability. Our results highlight that connectivity of language areas has a developmental pattern and is related to cognitive ability. PMID:25516399

L2-Proficiency-Dependent Laterality Shift in Structural Connectivity of Brain Language Pathways.

PubMed

Xiang, Huadong; van Leeuwen, Tessa Marije; Dediu, Dan; Roberts, Leah; Norris, David G; Hagoort, Peter

2015-08-01

Diffusion tensor imaging (DTI) and a longitudinal language learning approach were applied to investigate the relationship between the achieved second language (L2) proficiency during L2 learning and the reorganization of structural connectivity between core language areas. Language proficiency tests and DTI scans were obtained from German students before and after they completed an intensive 6-week course of the Dutch language. In the initial learning stage, with increasing L2 proficiency, the hemispheric dominance of the Brodmann area (BA) 6-temporal pathway (mainly along the arcuate fasciculus) shifted from the left to the right hemisphere. With further increased proficiency, however, lateralization dominance was again found in the left BA6-temporal pathway. This result is consistent with reports in the literature that imply a stronger involvement of the right hemisphere in L2 processing especially for less proficient L2 speakers. This is the first time that an L2 proficiency-dependent laterality shift in the structural connectivity of language pathways during L2 acquisition has been observed to shift from left to right and back to left hemisphere dominance with increasing L2 proficiency. The authors additionally find that changes in fractional anisotropy values after the course are related to the time elapsed between the two scans. The results suggest that structural connectivity in (at least part of) the perisylvian language network may be subject to fast dynamic changes following language learning.

Explosive percolation on directed networks due to monotonic flow of activity

NASA Astrophysics Data System (ADS)

Waagen, Alex; D'Souza, Raissa M.; Lu, Tsai-Ching

2017-07-01

An important class of real-world networks has directed edges, and in addition, some rank ordering on the nodes, for instance the popularity of users in online social networks. Yet, nearly all research related to explosive percolation has been restricted to undirected networks. Furthermore, information on such rank-ordered networks typically flows from higher-ranked to lower-ranked individuals, such as follower relations, replies, and retweets on Twitter. Here we introduce a simple percolation process on an ordered, directed network where edges are added monotonically with respect to the rank ordering. We show with a numerical approach that the emergence of a dominant strongly connected component appears to be discontinuous. Large-scale connectivity occurs at very high density compared with most percolation processes, and this holds not just for the strongly connected component structure but for the weakly connected component structure as well. We present analysis with branching processes, which explains this unusual behavior and gives basic intuition for the underlying mechanisms. We also show that before the emergence of a dominant strongly connected component, multiple giant strongly connected components may exist simultaneously. By adding a competitive percolation rule with a small bias to link uses of similar rank, we show this leads to formation of two distinct components, one of high-ranked users, and one of low-ranked users, with little flow between the two components.

[Introduction to grounded theory].

PubMed

Wang, Shou-Yu; Windsor, Carol; Yates, Patsy

2012-02-01

Grounded theory, first developed by Glaser and Strauss in the 1960s, was introduced into nursing education as a distinct research methodology in the 1970s. The theory is grounded in a critique of the dominant contemporary approach to social inquiry, which imposed "enduring" theoretical propositions onto study data. Rather than starting from a set theoretical framework, grounded theory relies on researchers distinguishing meaningful constructs from generated data and then identifying an appropriate theory. Grounded theory is thus particularly useful in investigating complex issues and behaviours not previously addressed and concepts and relationships in particular populations or places that are still undeveloped or weakly connected. Grounded theory data analysis processes include open, axial and selective coding levels. The purpose of this article was to explore the grounded theory research process and provide an initial understanding of this methodology.

STEM learning research through a funds of knowledge lens

NASA Astrophysics Data System (ADS)

Civil, Marta

2016-03-01

This article examines STEM learning as a cultural process with a focus on non-dominant communities. Building on my work in funds of knowledge and mathematics education, I present three vignettes to raise some questions around connections between in-school and out-of-school mathematics. How do we define competence? How do task and environment affect engagement? What is the role of affect, language, and cognition in different settings? These vignettes serve to highlight the complexity of moving across different domains of STEM practice—everyday life, school, and STEM disciplines. Based on findings from occupational interviews I discuss characteristics of learning and engaging in everyday practices and propose several areas for further research, including the nature of everyday STEM practices, valorization of knowledge, language choice, and different forms of engagement.

Energy aware swarm optimization with intercluster search for wireless sensor network.

PubMed

Thilagavathi, Shanmugasundaram; Geetha, Bhavani Gnanasambandan

2015-01-01

Wireless sensor networks (WSNs) are emerging as a low cost popular solution for many real-world challenges. The low cost ensures deployment of large sensor arrays to perform military and civilian tasks. Generally, WSNs are power constrained due to their unique deployment method which makes replacement of battery source difficult. Challenges in WSN include a well-organized communication platform for the network with negligible power utilization. In this work, an improved binary particle swarm optimization (PSO) algorithm with modified connected dominating set (CDS) based on residual energy is proposed for discovery of optimal number of clusters and cluster head (CH). Simulations show that the proposed BPSO-T and BPSO-EADS perform better than LEACH- and PSO-based system in terms of energy savings and QOS.

Carbon stock corridors to mitigate climate change and promote biodiversity in the tropics

NASA Astrophysics Data System (ADS)

Jantz, Patrick; Goetz, Scott; Laporte, Nadine

2014-02-01

A key issue in global conservation is how biodiversity co-benefits can be incorporated into land use and climate change mitigation activities, particularly those being negotiated under the United Nations to reduce emissions from tropical deforestation and forest degradation. Protected areas have been the dominant strategy for tropical forest conservation and they have increased substantially in recent decades. Avoiding deforestation by preserving carbon stored in vegetation between protected areas provides an opportunity to mitigate the effects of land use and climate change on biodiversity by maintaining habitat connectivity across landscapes. Here we use a high-resolution data set of vegetation carbon stock to map corridors traversing areas of highest biomass between protected areas in the tropics. The derived corridors contain 15% of the total unprotected aboveground carbon in the tropical region. A large number of corridors have carbon densities that approach or exceed those of the protected areas they connect, suggesting these are suitable areas for achieving both habitat connectivity and climate change mitigation benefits. To further illustrate how economic and biological information can be used for corridor prioritization on a regional scale, we conducted a multicriteria analysis of corridors in the Legal Amazon, identifying corridors with high carbon, high species richness and endemism, and low economic opportunity costs. We also assessed the vulnerability of corridors to future deforestation threat.

System efficiency of a tap transformer based grid connection topology applied on a direct driven generator for wind power.

PubMed

Apelfröjd, Senad; Eriksson, Sandra

2014-01-01

Results from experiments on a tap transformer based grid connection system for a variable speed vertical axis wind turbine are presented. The tap transformer based system topology consists of a passive diode rectifier, DC-link, IGBT inverter, LCL-filter, and tap transformer. Full range variable speed operation is enabled by using the different step-up ratios of a tap transformer. Simulations using MATLAB/Simulink have been performed in order to study the behavior of the system. A full experimental set up of the system has been used in the laboratory study, where a clone of the on-site generator was driven by an induction motor and the system was connected to a resistive load to better evaluate the performance. Furthermore, the system is run and evaluated for realistic wind speeds and variable speed operation. For a more complete picture of the system performance, a case study using real site Weibull parameters is done, comparing different tap selection options. The results show high system efficiency at nominal power and an increase in overall power output for full tap operation in comparison with the base case, a standard transformer. In addition, the loss distribution at different wind speeds is shown, which highlights the dominant losses at low and high wind speeds. Finally, means for further increasing the overall system efficiency are proposed.

System Efficiency of a Tap Transformer Based Grid Connection Topology Applied on a Direct Driven Generator for Wind Power

PubMed Central

2014-01-01

Results from experiments on a tap transformer based grid connection system for a variable speed vertical axis wind turbine are presented. The tap transformer based system topology consists of a passive diode rectifier, DC-link, IGBT inverter, LCL-filter, and tap transformer. Full range variable speed operation is enabled by using the different step-up ratios of a tap transformer. Simulations using MATLAB/Simulink have been performed in order to study the behavior of the system. A full experimental set up of the system has been used in the laboratory study, where a clone of the on-site generator was driven by an induction motor and the system was connected to a resistive load to better evaluate the performance. Furthermore, the system is run and evaluated for realistic wind speeds and variable speed operation. For a more complete picture of the system performance, a case study using real site Weibull parameters is done, comparing different tap selection options. The results show high system efficiency at nominal power and an increase in overall power output for full tap operation in comparison with the base case, a standard transformer. In addition, the loss distribution at different wind speeds is shown, which highlights the dominant losses at low and high wind speeds. Finally, means for further increasing the overall system efficiency are proposed. PMID:25258733

Reduction of lymph tissue false positives in pulmonary embolism detection

NASA Astrophysics Data System (ADS)

Ghanem, Bernard; Liang, Jianming; Bi, Jinbo; Salganicoff, Marcos; Krishnan, Arun

2008-03-01

Pulmonary embolism (PE) is a serious medical condition, characterized by the partial/complete blockage of an artery within the lungs. We have previously developed a fast yet effective approach for computer aided detection of PE in computed topographic pulmonary angiography (CTPA),1 which is capable of detecting both acute and chronic PEs, achieving a benchmark performance of 78% sensitivity at 4 false positives (FPs) per volume. By reviewing the FPs generated by this system, we found the most dominant type of FP, roughly one third of all FPs, to be lymph/connective tissue. In this paper, we propose a novel approach that specifically aims at reducing this FP type. Our idea is to explicitly exploit the anatomical context configuration of PE and lymph tissue in the lungs: a lymph FP connects to the airway and is located outside the artery, while a true PE should not connect to the airway and must be inside the artery. To realize this idea, given a detected candidate (i.e. a cluster of suspicious voxels), we compute a set of contextual features, including its distance to the airway based on local distance transform and its relative position to the artery based on fast tensor voting and Hessian "vesselness" scores. Our tests on unseen cases show that these features can reduce the lymph FPs by 59%, while improving the overall sensitivity by 3.4%.

Connectivity dominates larval replenishment in a coastal reef fish metapopulation

PubMed Central

Saenz-Agudelo, Pablo; Jones, Geoffrey P.; Thorrold, Simon R.; Planes, Serge

2011-01-01

Direct estimates of larval retention and connectivity are essential to understand the structure and dynamics of marine metapopulations, and optimize the size and spacing of reserves within networks of marine-protected areas (MPAs). For coral reef fishes, while there are some empirical estimates of self-recruitment at isolated populations, exchange among sub-populations has been rarely quantified. Here, we used microsatellite DNA markers and a likelihood-based parentage analysis to assess the relative magnitude of self-recruitment and exchange among eight geographically distinct sub-populations of the panda clownfish Amphiprion polymnus along 30 km of coastline near Port Moresby, Papua New Guinea. In addition, we used an assignment/exclusion test to identify immigrants arriving from genetically distinct sources. Overall, 82 per cent of the juveniles were immigrants while 18 per cent were progeny of parents genotyped in our focal metapopulation. Of the immigrants, only 6 per cent were likely to be genetically distinct from the focal metapopulation, suggesting most of the connectivity is among sub-populations from a rather homogeneous genetic pool. Of the 18 per cent that were progeny of known adults, two-thirds dispersed among the eight sub-populations and only one-third settled back into natal sub-populations. Comparison of our data with previous studies suggested that variation in dispersal distances is likely to be influenced by the geographical setting and spacing of sub-populations. PMID:21325328

Connectivity dominates larval replenishment in a coastal reef fish metapopulation.

PubMed

Saenz-Agudelo, Pablo; Jones, Geoffrey P; Thorrold, Simon R; Planes, Serge

2011-10-07

Direct estimates of larval retention and connectivity are essential to understand the structure and dynamics of marine metapopulations, and optimize the size and spacing of reserves within networks of marine-protected areas (MPAs). For coral reef fishes, while there are some empirical estimates of self-recruitment at isolated populations, exchange among sub-populations has been rarely quantified. Here, we used microsatellite DNA markers and a likelihood-based parentage analysis to assess the relative magnitude of self-recruitment and exchange among eight geographically distinct sub-populations of the panda clownfish Amphiprion polymnus along 30 km of coastline near Port Moresby, Papua New Guinea. In addition, we used an assignment/exclusion test to identify immigrants arriving from genetically distinct sources. Overall, 82 per cent of the juveniles were immigrants while 18 per cent were progeny of parents genotyped in our focal metapopulation. Of the immigrants, only 6 per cent were likely to be genetically distinct from the focal metapopulation, suggesting most of the connectivity is among sub-populations from a rather homogeneous genetic pool. Of the 18 per cent that were progeny of known adults, two-thirds dispersed among the eight sub-populations and only one-third settled back into natal sub-populations. Comparison of our data with previous studies suggested that variation in dispersal distances is likely to be influenced by the geographical setting and spacing of sub-populations.

Assessing temporal variations in connectivity through suspended sediment hysteresis analysis

NASA Astrophysics Data System (ADS)

Sherriff, Sophie; Rowan, John; Fenton, Owen; Jordan, Phil; Melland, Alice; Mellander, Per-Erik; hUallacháin, Daire Ó.

2016-04-01

Connectivity provides a valuable concept for understanding catchment-scale sediment dynamics. In intensive agricultural catchments, land management through tillage, high livestock densities and extensive land drainage practices significantly change hydromorphological behaviour and alter sediment supply and downstream delivery. Analysis of suspended sediment-discharge hysteresis has offered insights into sediment dynamics but typically on a limited selection of events. Greater availability of continuous high-resolution discharge and turbidity data and qualitative hysteresis metrics enables assessment of sediment dynamics during more events and over time. This paper assesses the utility of this approach to explore seasonal variations in connectivity. Data were collected from three small (c. 10 km2) intensive agricultural catchments in Ireland with contrasting morphologies, soil types, land use patterns and management practices, and are broadly defined as low-permeability supporting grassland, moderate-permeability supporting arable and high-permeability supporting arable. Suspended sediment concentration (using calibrated turbidity measurements) and discharge data were collected at 10-min resolution from each catchment outlet and precipitation data were collected from a weather station within each catchment. Event databases (67-90 events per catchment) collated information on sediment export metrics, hysteresis category (e.g., clockwise, anti-clockwise, no hysteresis), numeric hysteresis index, and potential hydro-meteorological controls on sediment transport including precipitation amount, duration, intensity, stream flow and antecedent soil moisture and rainfall. Statistical analysis of potential controls on sediment export was undertaken using Pearson's correlation coefficient on separate hysteresis categories in each catchment. Sediment hysteresis fluctuations through time were subsequently assessed using the hysteresis index. Results showed the numeric hysteresis index varied over time in all three catchments. The exact response was catchment specific reflecting changing sediment availability and connectivity through time as indicated by dominant controls. In the low-permeability grassland catchment, proximal sources dominated which was consistent with observations of active channel bank erosion. Seasonal increases in rainfall increased the erosion potential but continuous grassland cover mitigated against hillslope sediment contributions despite high hydrological connectivity and surface pathways. The moderate-permeability arable catchment was dominated by events with a distal source component but those with both proximal and distal sediment sources yielded the highest sediment quantities. These events were driven by rainfall parameters suggesting sediment were surface derived and the hillslope was hydrologically connected during most events. Through time, a sustained period of rainfall increased the magnitude of negative hysteresis, likely demonstrating increasing surface hydrological connectivity due to increased groundwater saturation. Where increased hydrological connectivity coincided with low groundcover, the largest sediment exports were recorded. Events in the high permeability catchment indicated predominantly proximal sediments despite abundant distal sources from tilled fields. The infiltration dominated high permeability soils hydrologically disconnected these field sources and limited sediment supply. However, the greatest sediment export occurred in this catchment suggesting thresholds existed, which when exceeded during higher magnitude events, resulted in efficient conveyance of sediments. Hysteresis analysis offers wider utility as a tool to understand sediment pathways and connectivity issues with applications to catchment management strategies.

Recessive and dominant mutations in COL12A1 cause a novel EDS/myopathy overlap syndrome in humans and mice

PubMed Central

Zou, Yaqun; Zwolanek, Daniela; Izu, Yayoi; Gandhy, Shreya; Schreiber, Gudrun; Brockmann, Knut; Devoto, Marcella; Tian, Zuozhen; Hu, Ying; Veit, Guido; Meier, Markus; Stetefeld, Jörg; Hicks, Debbie; Straub, Volker; Voermans, Nicol C.; Birk, David E.; Barton, Elisabeth R.; Koch, Manuel; Bönnemann, Carsten G.

2014-01-01

Collagen VI-related myopathies are disorders of connective tissue presenting with an overlap phenotype combining clinical involvement from the muscle and from the connective tissue. Not all patients displaying related overlap phenotypes between muscle and connective tissue have mutations in collagen VI. Here, we report a homozygous recessive loss of function mutation and a de novo dominant mutation in collagen XII (COL12A1) as underlying a novel overlap syndrome involving muscle and connective tissue. Two siblings homozygous for a loss of function mutation showed widespread joint hyperlaxity combined with weakness precluding independent ambulation, while the patient with the de novo missense mutation was more mildly affected, showing improvement including the acquisition of walking. A mouse model with inactivation of the Col12a1 gene showed decreased grip strength, a delay in fiber-type transition and a deficiency in passive force generation while the muscle seems more resistant to eccentric contraction induced force drop, indicating a role for a matrix-based passive force-transducing elastic element in the generation of the weakness. This new muscle connective tissue overlap syndrome expands on the emerging importance of the muscle extracellular matrix in the pathogenesis of muscle disease. PMID:24334604

Exposing the Challenges and Coping Strategies of Field-Ecology Graduate Students

NASA Astrophysics Data System (ADS)

Leon-Beck, Mika; Dodick, Jeff

2012-11-01

In this paper, we expose the unique challenges confronting graduate field-ecology students and the coping strategies they adopt to overcome such challenges. To do so, we used a qualitative (in vivo) research method that combines interviews, observations and open questionnaires with a group of five Israeli graduate students. The two major challenges that the students faced were the uncontrolled nature of field research (or complexity), and the nature of field setting, which isolated the students from authoritative guidance. In response to these challenges, the students developed a set of research skills which were expressed in this study by a series of three (metacognitive) strategies which we designated as 'protocol-dominated', 'intermediate' or 'field-dominated'. In order to develop such research skills, our subjects rely upon declarative and procedural knowledge. In contrast to declarative knowledge, learned in coursework, procedural knowledge is learned and activated via the situated experience of implementing research in authentic field environments. We also found that fieldwork complexity imposes itself the minute the students step into the field; potentially, this can negatively impact students' motivation. However, as the students accumulate field experience and acquire the knowledge and skills needed to overcome the field's complexity, their motivation improves. Recognizing the unique learning components connected to field research will help novice students better cope with fieldwork challenges, as well as help their advisers in guiding them. This work also has implications for designing inquiry curricula in field sciences for university and high-school students.

Differential Modulation of Spontaneous and Evoked Thalamocortical Network Activity by Acetylcholine Level In Vitro

PubMed Central

Wester, Jason C.

2013-01-01

Different levels of cholinergic neuromodulatory tone have been hypothesized to set the state of cortical circuits either to one dominated by local cortical recurrent activity (low ACh) or to one dependent on thalamic input (high ACh). High ACh levels depress intracortical but facilitate thalamocortical synapses, whereas low levels potentiate intracortical synapses. Furthermore, recent work has implicated the thalamus in controlling cortical network state during waking and attention, when ACh levels are highest. To test this hypothesis, we used rat thalamocortical slices maintained in medium to generate spontaneous up- and down-states and applied different ACh concentrations to slices in which thalamocortical connections were either maintained or severed. The effects on spontaneous and evoked up-states were measured using voltage-sensitive dye imaging, intracellular recordings, local field potentials, and single/multiunit activity. We found that high ACh can increase the frequency of spontaneous up-states, but reduces their duration in slices with intact thalamocortical connections. Strikingly, when thalamic connections are severed, high ACh instead greatly reduces or abolishes spontaneous up-states. Furthermore, high ACh reduces the spatial propagation, velocity, and depolarization amplitude of evoked up-states. In contrast, low ACh dramatically increases up-state frequency regardless of the presence or absence of intact thalamocortical connections and does not reduce the duration, spatial propagation, or velocity of evoked up-states. Therefore, our data support the hypothesis that strong cholinergic modulation increases the influence, and thus the signal-to-noise ratio, of afferent input over local cortical activity and that lower cholinergic tone enhances recurrent cortical activity regardless of thalamic input. PMID:24198382

What do District Health Planners in Tanzania think about improving priority setting using 'Accountability for Reasonableness'?

PubMed Central

Mshana, Simon; Shemilu, Haji; Ndawi, Benedict; Momburi, Roman; Olsen, Oystein Evjen; Byskov, Jens; Martin, Douglas K

2007-01-01

Background Priority setting in every health system is complex and difficult. In less wealthy countries the dominant approach to priority setting has been Burden of Disease (BOD) and cost-effectiveness analysis (CEA), which is helpful, but insufficient because it focuses on a narrow range of values – need and efficiency – and not the full range of relevant values, including legitimacy and fairness. 'Accountability for reasonableness' is a conceptual framework for legitimate and fair priority setting and is empirically based and ethically justified. It connects priority setting to broader, more fundamental, democratic deliberative processes that have an impact on social justice and equity. Can 'accountability for reasonableness' be helpful for improving priority setting in less wealthy countries? Methods In 2005, Tanzanian scholars from the Primary Health Care Institute (PHCI) conducted 6 capacity building workshops with senior health staff, district planners and managers, and representatives of the Tanzanian Ministry of Health to discussion improving priority setting in Tanzania using 'accountability for reasonableness'. The purpose of this paper is to describe this initiative and the participants' views about the approach. Results The approach to improving priority setting using 'accountability for reasonableness' was viewed by district decision makers with enthusiastic favour because it was the first framework that directly addressed their priority setting concerns. High level Ministry of Health participants were also very supportive of the approach. Conclusion Both Tanzanian district and governmental health planners viewed the 'accountability for reasonableness' approach with enthusiastic favour because it was the first framework that directly addressed their concerns. PMID:17997824

Single bus star connected reluctance drive and method

DOEpatents

Fahimi, Babak; Shamsi, Pourya

2016-05-10

A system and methods for operating a switched reluctance machine includes a controller, an inverter connected to the controller and to the switched reluctance machine, a hysteresis control connected to the controller and to the inverter, a set of sensors connected to the switched reluctance machine and to the controller, the switched reluctance machine further including a set of phases the controller further comprising a processor and a memory connected to the processor, wherein the processor programmed to execute a control process and a generation process.

Julia Sets in Parameter Spaces

NASA Astrophysics Data System (ADS)

Buff, X.; Henriksen, C.

Given a complex number λ of modulus 1, we show that the bifurcation locus of the one parameter family {fb(z)=λz+bz2+z3}b∈ contains quasi-conformal copies of the quadratic Julia set J(λz+z2). As a corollary, we show that when the Julia set J(λz+z2) is not locally connected (for example when z|-->λz+z2 has a Cremer point at 0), the bifurcation locus is not locally connected. To our knowledge, this is the first example of complex analytic parameter space of dimension 1, with connected but non-locally connected bifurcation locus. We also show that the set of complex numbers λ of modulus 1, for which at least one of the parameter rays has a non-trivial accumulation set, contains a dense Gδ subset of S1.

Improved Diagnostic Accuracy of Alzheimer's Disease by Combining Regional Cortical Thickness and Default Mode Network Functional Connectivity: Validated in the Alzheimer's Disease Neuroimaging Initiative Set.

PubMed

Park, Ji Eun; Park, Bumwoo; Kim, Sang Joon; Kim, Ho Sung; Choi, Choong Gon; Jung, Seung Chai; Oh, Joo Young; Lee, Jae-Hong; Roh, Jee Hoon; Shim, Woo Hyun

2017-01-01

To identify potential imaging biomarkers of Alzheimer's disease by combining brain cortical thickness (CThk) and functional connectivity and to validate this model's diagnostic accuracy in a validation set. Data from 98 subjects was retrospectively reviewed, including a study set (n = 63) and a validation set from the Alzheimer's Disease Neuroimaging Initiative (n = 35). From each subject, data for CThk and functional connectivity of the default mode network was extracted from structural T1-weighted and resting-state functional magnetic resonance imaging. Cortical regions with significant differences between patients and healthy controls in the correlation of CThk and functional connectivity were identified in the study set. The diagnostic accuracy of functional connectivity measures combined with CThk in the identified regions was evaluated against that in the medial temporal lobes using the validation set and application of a support vector machine. Group-wise differences in the correlation of CThk and default mode network functional connectivity were identified in the superior temporal ( p < 0.001) and supramarginal gyrus ( p = 0.007) of the left cerebral hemisphere. Default mode network functional connectivity combined with the CThk of those two regions were more accurate than that combined with the CThk of both medial temporal lobes (91.7% vs. 75%). Combining functional information with CThk of the superior temporal and supramarginal gyri in the left cerebral hemisphere improves diagnostic accuracy, making it a potential imaging biomarker for Alzheimer's disease.

Real World Graph Connectivity

ERIC Educational Resources Information Center

Lind, Joy; Narayan, Darren

2009-01-01

We present the topic of graph connectivity along with a famous theorem of Menger in the real-world setting of the national computer network infrastructure of "National LambdaRail". We include a set of exercises where students reinforce their understanding of graph connectivity by analysing the "National LambdaRail" network. Finally, we give…

Effects of eye dominance (left vs. right) and cannabis use on intermanual coordination and negative symptoms in schizophrenia patients.

PubMed

Gorynia, Inge; Schwaiger, Markus; Heinz, Andreas

2014-12-01

Based on the previous findings, it has been assumed that in schizophrenia patients, eye dominance and cannabis use will affect negative symptoms and intermanual coordination (IMC), an index of interhemispheric communication. But eye dominance, specifically the clinical findings for it, has been neglected in schizophrenia research. We therefore investigated its effects in 52 right-handed (36 right-eyed and 16 left-eyed) and 51 left-handed (35 left-eyed and 16 right-eyed) schizophrenia in-patients without and with drug use. Eye dominance affected IMC in all schizophrenia patients. When comparing right- and left-handers, we found that this result was only significant in the right-handed patients and in the smaller subgroup without drug use. In the right-handers, left eye dominance-like left-handedness-was associated with higher values in IMC and less pronounced manifestation of negative symptoms, right eye dominance was not. Thus, left-eyed right-handers may be more closely related to left-handers than to right-handers. In accordance with the results from the literature, we suggest that these findings are due to better interhemispheric connections and less impairment of white matter structures, especially in right-hemispheric regions. Moreover, cannabis use was related to higher scores in IMC and less pronounced negative symptoms, but only in the right-eyed and not in the left-eyed right-handers or in the left-handers. Hence, differences in eye dominance and handedness may be partially responsible for different results in interhemispheric connections among cannabis users. In conclusion, both eye dominance and use of cannabis should be taken into account when assessing clinical symptoms in schizophrenia patients.

Range-wide connectivity of priority areas for Greater Sage-Grouse: Implications for long-term conservation from graph theory

USGS Publications Warehouse

Crist, Michele R.; Knick, Steven T.; Hanser, Steven E.

2017-01-01

The delineation of priority areas in western North America for managing Greater Sage-Grouse (Centrocercus urophasianus) represents a broad-scale experiment in conservation biology. The strategy of limiting spatial disturbance and focusing conservation actions within delineated areas may benefit the greatest proportion of Greater Sage-Grouse. However, land use under normal restrictions outside priority areas potentially limits dispersal and gene flow, which can isolate priority areas and lead to spatially disjunct populations. We used graph theory, representing priority areas as spatially distributed nodes interconnected by movement corridors, to understand the capacity of priority areas to function as connected networks in the Bi-State, Central, and Washington regions of the Greater Sage-Grouse range. The Bi-State and Central networks were highly centralized; the dominant pathways and shortest linkages primarily connected a small number of large and centrally located priority areas. These priority areas are likely strongholds for Greater Sage-Grouse populations and might also function as refugia and sources. Priority areas in the Central network were more connected than those in the Bi-State and Washington networks. Almost 90% of the priority areas in the Central network had ≥2 pathways to other priority areas when movement through the landscape was set at an upper threshold (effective resistance, ER12). At a lower threshold (ER4), 83 of 123 priority areas in the Central network were clustered in 9 interconnected subgroups. The current conservation strategy has risks; 45 of 61 priority areas in the Bi-State network, 68 of 123 in the Central network, and all 4 priority areas in the Washington network had ≤1 connection to another priority area at the lower ER4threshold. Priority areas with few linkages also averaged greater environmental resistance to movement along connecting pathways. Without maintaining corridors to larger priority areas or a clustered group, isolation of small priority areas could lead to regional loss of Greater Sage-Grouse

On the locating domination number of P n [trianglerightequal] H graph

NASA Astrophysics Data System (ADS)

Agustin Retno Wardani, Dwi; Hesti Agustin, Ika; Dafik; Alfarisi, Ridho

2018-04-01

A subset D of V(G) is called a vertex dominating set of G if every vertex not in D is adjacent to some vertices in D. A graph G = (V, E) is called a locating dominating set if for every two vertices u,v\\in V(G)-D, N(v)\\cap D\

Dynamic connectivity regression: Determining state-related changes in brain connectivity

PubMed Central

Cribben, Ivor; Haraldsdottir, Ragnheidur; Atlas, Lauren Y.; Wager, Tor D.; Lindquist, Martin A.

2014-01-01

Most statistical analyses of fMRI data assume that the nature, timing and duration of the psychological processes being studied are known. However, often it is hard to specify this information a priori. In this work we introduce a data-driven technique for partitioning the experimental time course into distinct temporal intervals with different multivariate functional connectivity patterns between a set of regions of interest (ROIs). The technique, called Dynamic Connectivity Regression (DCR), detects temporal change points in functional connectivity and estimates a graph, or set of relationships between ROIs, for data in the temporal partition that falls between pairs of change points. Hence, DCR allows for estimation of both the time of change in connectivity and the connectivity graph for each partition, without requiring prior knowledge of the nature of the experimental design. Permutation and bootstrapping methods are used to perform inference on the change points. The method is applied to various simulated data sets as well as to an fMRI data set from a study (N=26) of a state anxiety induction using a socially evaluative threat challenge. The results illustrate the method’s ability to observe how the networks between different brain regions changed with subjects’ emotional state. PMID:22484408

Effects of host social hierarchy on disease persistence.

PubMed

Davidson, Ross S; Marion, Glenn; Hutchings, Michael R

2008-08-07

The effects of social hierarchy on population dynamics and epidemiology are examined through a model which contains a number of fundamental features of hierarchical systems, but is simple enough to allow analytical insight. In order to allow for differences in birth rates, contact rates and movement rates among different sets of individuals the population is first divided into subgroups representing levels in the hierarchy. Movement, representing dominance challenges, is allowed between any two levels, giving a completely connected network. The model includes hierarchical effects by introducing a set of dominance parameters which affect birth rates in each social level and movement rates between social levels, dependent upon their rank. Although natural hierarchies vary greatly in form, the skewing of contact patterns, introduced here through non-uniform dominance parameters, has marked effects on the spread of disease. A simple homogeneous mixing differential equation model of a disease with SI dynamics in a population subject to simple birth and death process is presented and it is shown that the hierarchical model tends to this as certain parameter regions are approached. Outside of these parameter regions correlations within the system give rise to deviations from the simple theory. A Gaussian moment closure scheme is developed which extends the homogeneous model in order to take account of correlations arising from the hierarchical structure, and it is shown that the results are in reasonable agreement with simulations across a range of parameters. This approach helps to elucidate the origin of hierarchical effects and shows that it may be straightforward to relate the correlations in the model to measurable quantities which could be used to determine the importance of hierarchical corrections. Overall, hierarchical effects decrease the levels of disease present in a given population compared to a homogeneous unstructured model, but show higher levels of disease than structured models with no hierarchy. The separation between these three models is greatest when the rate of dominance challenges is low, reducing mixing, and when the disease prevalence is low. This suggests that these effects will often need to be considered in models being used to examine the impact of control strategies where the low disease prevalence behaviour of a model is critical.

Functional resting-state connectivity of the human motor network: differences between right- and left-handers.

PubMed

Pool, Eva-Maria; Rehme, Anne K; Eickhoff, Simon B; Fink, Gereon R; Grefkes, Christian

2015-04-01

Handedness is associated with differences in activation levels in various motor tasks performed with the dominant or non-dominant hand. Here we tested whether handedness is reflected in the functional architecture of the motor system even in the absence of an overt motor task. Using resting-state functional magnetic resonance imaging we investigated 18 right- and 18 left-handers. Whole-brain functional connectivity maps of the primary motor cortex (M1), supplementary motor area (SMA), dorsolateral premotor cortex (PMd), pre-SMA, inferior frontal junction and motor putamen were compared between right- and left-handers. We further used a multivariate linear support vector machine (SVM) classifier to reveal the specificity of brain regions for classifying handedness based on individual resting-state maps. Using left M1 as seed region, functional connectivity analysis revealed stronger interhemispheric functional connectivity between left M1 and right PMd in right-handers as compared to left-handers. This connectivity cluster contributed to the individual classification of right- and left-handers with 86.2% accuracy. Consistently, also seeding from right PMd yielded a similar handedness-dependent effect in left M1, albeit with lower classification accuracy (78.1%). Control analyses of the other resting-state networks including the speech and the visual network revealed no significant differences in functional connectivity related to handedness. In conclusion, our data revealed an intrinsically higher functional connectivity in right-handers. These results may help to explain that hand preference is more lateralized in right-handers than in left-handers. Furthermore, enhanced functional connectivity between left M1 and right PMd may serve as an individual marker of handedness. Copyright © 2015 Elsevier Inc. All rights reserved.

Functional resting-state connectivity of the human motor network: Differences between right- and left-handers

PubMed Central

Pool, Eva-Maria; Rehme, Anne K.; Eickhoff, Simon B.; Fink, Gereon R.; Grefkes, Christian

2016-01-01

Handedness is associated with differences in activation levels in various motor tasks performed with the dominant or non-dominant hand. Here we tested whether handedness is reflected in the functional architecture of the motor system even in the absence of an overt motor task. Using resting-state functional magnetic resonance imaging we investigated 18 right- and 18 left-handers. Whole-brain functional connectivity maps of the primary motor cortex (M1), supplementary motor area (SMA), dorsolateral premotor cortex (PMd), pre-SMA, inferior frontal junction and motor putamen were compared between right- and left-handers. We further used a multivariate linear support vector machine (SVM) classifier to reveal the specificity of brain regions for classifying handedness based on individual resting-state maps. Using left M1 as seed region, functional connectivity analysis revealed stronger interhemispheric functional connectivity between left M1 and right PMd in right-handers as compared to left-handers. This connectivity cluster contributed to the individual classification of right- and left-handers with 86.2% accuracy. Consistently, also seeding from right PMd yielded a similar handedness-dependent effect in left M1, albeit with lower classification accuracy (78.1%). Control analyses of the other resting-state networks including the speech and the visual network revealed no significant differences in functional connectivity related to handedness. In conclusion, our data revealed an intrinsically higher functional connectivity in right-handers. These results may help to explain that hand preference is more lateralized in right-handers than in left-handers. Furthermore, enhanced functional connectivity between left M1 and right PMd may serve as an individual marker of handedness. PMID:25613438

Neuronal avalanches of a self-organized neural network with active-neuron-dominant structure.

PubMed

Li, Xiumin; Small, Michael

2012-06-01

Neuronal avalanche is a spontaneous neuronal activity which obeys a power-law distribution of population event sizes with an exponent of -3/2. It has been observed in the superficial layers of cortex both in vivo and in vitro. In this paper, we analyze the information transmission of a novel self-organized neural network with active-neuron-dominant structure. Neuronal avalanches can be observed in this network with appropriate input intensity. We find that the process of network learning via spike-timing dependent plasticity dramatically increases the complexity of network structure, which is finally self-organized to be active-neuron-dominant connectivity. Both the entropy of activity patterns and the complexity of their resulting post-synaptic inputs are maximized when the network dynamics are propagated as neuronal avalanches. This emergent topology is beneficial for information transmission with high efficiency and also could be responsible for the large information capacity of this network compared with alternative archetypal networks with different neural connectivity.

Landscape corridors can increase invasion by an exotic species and reduce diversity of native species.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Resasco, Julian; et al,

2014-04-01

Abstract. Landscape corridors are commonly used to mitigate negative effects of habitat fragmentation, but concerns persist that they may facilitate the spread of invasive species. In a replicated landscape experiment of open habitat, we measured effects of corridors on the invasive fire ant, Solenopsis invicta, and native ants. Fire ants have two social forms: polygyne, which tend to disperse poorly but establish at high densities, and monogyne, which disperse widely but establish at lower densities. In landscapes dominated by polygyne fire ants, fire ant abundance was higher and native ant diversity was lower in habitat patches connected by corridors thanmore » in unconnected patches. Conversely, in landscapes dominated by monogyne fire ants, connectivity had no influence on fire ant abundance and native ant diversity. Polygyne fire ants dominated recently created landscapes, suggesting that these corridor effects may be transient. Our results suggest that corridors can facilitate invasion and they highlight the importance of considering species’ traits when assessing corridor utility.« less

Post-Crisis, Post-Ford and Post-Gender? Youth Identities in an Era of Austerity

ERIC Educational Resources Information Center

McDowell, Linda

2012-01-01

In this review I explore the connections between debates about the transformation of work in a service-dominated economy and those about classed and gendered identities. I suggest they might usefully be connected in analyses of disadvantage and exclusion among working-class young people. Youth involvement in protest and unrest in English cities,…

The Effects of rTMS Combined with Motor Training on Functional Connectivity in Alpha Frequency Band.

PubMed

Jin, Jing-Na; Wang, Xin; Li, Ying; Jin, Fang; Liu, Zhi-Peng; Yin, Tao

2017-01-01

It has recently been reported that repetitive transcranial magnetic stimulation combined with motor training (rTMS-MT) could improve motor function in post-stroke patients. However, the effects of rTMS-MT on cortical function using functional connectivity and graph theoretical analysis remain unclear. Ten healthy subjects were recruited to receive rTMS immediately before application of MT. Low frequency rTMS was delivered to the dominant hemisphere and non-dominant hand performed MT over 14 days. The reaction time of Nine-Hole Peg Test and electroencephalography (EEG) in resting condition with eyes closed were recorded before and after rTMS-MT. Functional connectivity was assessed by phase synchronization index (PSI), and subsequently thresholded to construct undirected graphs in alpha frequency band (8-13 Hz). We found a significant decrease in reaction time after rTMS-MT. The functional connectivity between the parietal and frontal cortex, and the graph theory statistics of node degree and efficiency in the parietal cortex increased. Besides the functional connectivity between premotor and frontal cortex, the degree and efficiency of premotor cortex showed opposite results. In addition, the number of connections significantly increased within inter-hemispheres and inter-regions. In conclusion, this study could be helpful in our understanding of how rTMS-MT modulates brain activity. The methods and results in this study could be taken as reference in future studies of the effects of rTMS-MT in stroke patients.

Did Cosmology Trigger the Origin of the Solar System?

NASA Technical Reports Server (NTRS)

Blome, H.-J.; Wilson, T. L.

2011-01-01

It is a matter of curious coincidence that the Solar System formed 4.6 billion years ago around the same epoch that the Friedmann-Lemaitre (FL) universe became -dominated or dark-energy-dominated, where is the cosmological constant. This observation was made in the context of known gravitational anomalies that affect spacecraft orbits during planetary flyby's and the Pioneer anomaly, both possibly having connections with cosmology. In addition, it has been known for some time that the Universe is not only expanding but accelerating as well. Hence one must add the onset of cosmological acceleration in the FL universe as having a possible influence on the origin of the Solar System. These connections will now be examined in greater detail.

Simulation of dynamic expansion, contraction, and connectivity in a mountain stream network

NASA Astrophysics Data System (ADS)

Ward, Adam S.; Schmadel, Noah M.; Wondzell, Steven M.

2018-04-01

Headwater stream networks expand and contract in response to changes in stream discharge. The changes in the extent of the stream network are also controlled by geologic or geomorphic setting - some reaches go dry even under relatively wet conditions, other reaches remain flowing under relatively dry conditions. While such patterns are well recognized, we currently lack tools to predict the extent of the stream network and the times and locations where the network is dry within large river networks. Here, we develop a perceptual model of the river corridor in a headwater mountainous catchment, translate this into a reduced-complexity mechanistic model, and implement the model to examine connectivity and network extent over an entire water year. Our model agreed reasonably well with our observations, showing that the extent and connectivity of the river network was most sensitive to hydrologic forcing under the lowest discharges (Qgauge < 1 L s-1), that at intermediate discharges (1 L s-1 < Qgauge < 10 L s-1) the extent of the network changed dramatically with changes in discharge, and that under wet conditions (Qgauge > 10 L s-1) the extent of the network was relatively insensitive to hydrologic forcing and was instead determined by the network topology. We do not expect that the specific thresholds observed in this study would be transferable to other catchments with different geology, topology, or hydrologic forcing. However, we expect that the general pattern should be robust: the dominant controls will shift from hydrologic forcing to geologic setting as discharge increases. Furthermore, our method is readily transferable as the model can be applied with minimal data requirements (a single stream gauge, a digital terrain model, and estimates of hydrogeologic properties) to estimate flow duration or connectivity along the river corridor in unstudied catchments. As the available information increases, the model could be better calibrated to match site-specific observations of network extent, locations of dry reaches, or solute break through curves as demonstrated in this study. Based on the low initial data requirements and ability to later tune the model to a specific site, we suggest example applications of this parsimonious model that may prove useful to both researchers and managers.

Improved Diagnostic Accuracy of Alzheimer's Disease by Combining Regional Cortical Thickness and Default Mode Network Functional Connectivity: Validated in the Alzheimer's Disease Neuroimaging Initiative Set

PubMed Central

Park, Ji Eun; Park, Bumwoo; Kim, Ho Sung; Choi, Choong Gon; Jung, Seung Chai; Oh, Joo Young; Lee, Jae-Hong; Roh, Jee Hoon; Shim, Woo Hyun

2017-01-01

Objective To identify potential imaging biomarkers of Alzheimer's disease by combining brain cortical thickness (CThk) and functional connectivity and to validate this model's diagnostic accuracy in a validation set. Materials and Methods Data from 98 subjects was retrospectively reviewed, including a study set (n = 63) and a validation set from the Alzheimer's Disease Neuroimaging Initiative (n = 35). From each subject, data for CThk and functional connectivity of the default mode network was extracted from structural T1-weighted and resting-state functional magnetic resonance imaging. Cortical regions with significant differences between patients and healthy controls in the correlation of CThk and functional connectivity were identified in the study set. The diagnostic accuracy of functional connectivity measures combined with CThk in the identified regions was evaluated against that in the medial temporal lobes using the validation set and application of a support vector machine. Results Group-wise differences in the correlation of CThk and default mode network functional connectivity were identified in the superior temporal (p < 0.001) and supramarginal gyrus (p = 0.007) of the left cerebral hemisphere. Default mode network functional connectivity combined with the CThk of those two regions were more accurate than that combined with the CThk of both medial temporal lobes (91.7% vs. 75%). Conclusion Combining functional information with CThk of the superior temporal and supramarginal gyri in the left cerebral hemisphere improves diagnostic accuracy, making it a potential imaging biomarker for Alzheimer's disease. PMID:29089831

Extremal values on Zagreb indices of trees with given distance k-domination number.

PubMed

Pei, Lidan; Pan, Xiangfeng

2018-01-01

Let [Formula: see text] be a graph. A set [Formula: see text] is a distance k -dominating set of G if for every vertex [Formula: see text], [Formula: see text] for some vertex [Formula: see text], where k is a positive integer. The distance k -domination number [Formula: see text] of G is the minimum cardinality among all distance k -dominating sets of G . The first Zagreb index of G is defined as [Formula: see text] and the second Zagreb index of G is [Formula: see text]. In this paper, we obtain the upper bounds for the Zagreb indices of n -vertex trees with given distance k -domination number and characterize the extremal trees, which generalize the results of Borovićanin and Furtula (Appl. Math. Comput. 276:208-218, 2016). What is worth mentioning, for an n -vertex tree T , is that a sharp upper bound on the distance k -domination number [Formula: see text] is determined.

Is Earth F**ked? Dynamical Futility of Global Environmental Management and Possibilities for Sustainability via Direct Action Activism

NASA Astrophysics Data System (ADS)

wErnEr, B.

2012-12-01

Environmental challenges are dynamically generated within the dominant global culture principally by the mismatch between short-time-scale market and political forces driving resource extraction/use and longer-time-scale accommodations of the Earth system to these changes. Increasing resource demand is leading to the development of two-way, nonlinear interactions between human societies and environmental systems that are becoming global in extent, either through globalized markets and other institutions or through coupling to global environmental systems such as climate. These trends are further intensified by dissipation-reducing technological advances in transactions, communication and transport, which suppress emergence of longer-time-scale economic and political levels of description and facilitate long-distance connections, and by predictive environmental modeling, which strengthens human connections to a short-time-scale virtual Earth, and weakens connections to the longer time scales of the actual Earth. Environmental management seeks to steer fast scale economic and political interests of a coupled human-environmental system towards longer-time-scale consideration of benefits and costs by operating within the confines of the dominant culture using a linear, engineering-type connection to the system. Perhaps as evidenced by widespread inability to meaningfully address such global environmental challenges as climate change and soil degradation, nonlinear connections reduce the ability of managers to operate outside coupled human-environmental systems, decreasing their effectiveness in steering towards sustainable interactions and resulting in managers slaved to short-to-intermediate-term interests. In sum, the dynamics of the global coupled human-environmental system within the dominant culture precludes management for stable, sustainable pathways and promotes instability. Environmental direct action, resistance taken from outside the dominant culture, as in protests, blockades and sabotage by indigenous peoples, workers, anarchists and other activist groups, increases dissipation within the coupled system over fast to intermediate scales and pushes for changes in the dominant culture that favor transition to a stable, sustainable attractor. These dynamical relationships are illustrated and explored using a numerical model that simulates the short-, intermediate- and long-time-scale dynamics of the coupled human-environmental system. At fast scales, economic and political interests exploit environmental resources through a maze of environmental management and resistance, guided by virtual Earth predictions. At intermediate scales, managers become slaved to economic and political interests, which adapt to and repress resistance, and resistance is guided by patterns of environmental destruction. At slow scales, resistance interacts with the cultural context, which co-evolves with the environment. The transition from unstable dynamics to sustainability is sensitively dependent on the level of participation in and repression of resistance. Because of their differing impact inside and outside the dominant culture, virtual Earth predictions can either promote or oppose sustainability. Supported by the National Science Foundation, Geomorphology and Land Use Dynamics Program.

Topology-selective jamming of fully-connected, code-division random-access networks

NASA Technical Reports Server (NTRS)

Polydoros, Andreas; Cheng, Unjeng

1990-01-01

The purpose is to introduce certain models of topology selective stochastic jamming and examine its impact on a class of fully-connected, spread-spectrum, slotted ALOHA-type random access networks. The theory covers dedicated as well as half-duplex units. The dominant role of the spatial duty factor is established, and connections with the dual concept of time selective jamming are discussed. The optimal choices of coding rate and link access parameters (from the users' side) and the jamming spatial fraction are numerically established for DS and FH spreading.

Neural-activity mapping of memory-based dominance in the crow: neural networks integrating individual discrimination and social behaviour control.

PubMed

Nishizawa, K; Izawa, E-I; Watanabe, S

2011-12-01

Large-billed crows (Corvus macrorhynchos), highly social birds, form stable dominance relationships based on the memory of win/loss outcomes of first encounters and on individual discrimination. This socio-cognitive behaviour predicts the existence of neural mechanisms for integration of social behaviour control and individual discrimination. This study aimed to elucidate the neural substrates of memory-based dominance in crows. First, the formation of dominance relationships was confirmed between males in a dyadic encounter paradigm. Next, we examined whether neural activities in 22 focal nuclei of pallium and subpallium were correlated with social behaviour and stimulus familiarity after exposure to dominant/subordinate familiar individuals and unfamiliar conspecifics. Neural activity was determined by measuring expression level of the immediate-early-gene (IEG) protein Zenk. Crows displayed aggressive and/or submissive behaviour to opponents less frequently but more discriminatively in subsequent encounters, suggesting stable dominance based on memory, including win/loss outcomes of the first encounters and individual discrimination. Neural correlates of aggressive and submissive behaviour were found in limbic subpallium including septum, bed nucleus of the striae terminalis (BST), and nucleus taeniae of amygdala (TnA), but also those to familiarity factor in BST and TnA. Contrastingly, correlates of social behaviour were little in pallium and those of familiarity with exposed individuals were identified in hippocampus, medial meso-/nidopallium, and ventro-caudal nidopallium. Given the anatomical connection and neural response patterns of the focal nuclei, neural networks connecting pallium and limbic subpallium via hippocampus could be involved in the integration of individual discrimination and social behaviour control in memory-based dominance in the crow. Copyright © 2011 IBRO. Published by Elsevier Ltd. All rights reserved.

Motor "dexterity"?: Evidence that left hemisphere lateralization of motor circuit connectivity is associated with better motor performance in children.

PubMed

Barber, Anita D; Srinivasan, Priti; Joel, Suresh E; Caffo, Brian S; Pekar, James J; Mostofsky, Stewart H

2012-01-01

Motor control relies on well-established motor circuits, which are critical for typical child development. Although many imaging studies have examined task activation during motor performance, none have examined the relationship between functional intrinsic connectivity and motor ability. The current study investigated the relationship between resting state functional connectivity within the motor network and motor performance assessment outside of the scanner in 40 typically developing right-handed children. Better motor performance correlated with greater left-lateralized (mean left hemisphere-mean right hemisphere) motor circuit connectivity. Speed, rhythmicity, and control of movements were associated with connectivity within different individual region pairs: faster speed was associated with more left-lateralized putamen-thalamus connectivity, less overflow with more left-lateralized supplementary motor-primary motor connectivity, and less dysrhythmia with more left-lateralized supplementary motor-anterior cerebellar connectivity. These findings suggest that for right-handed children, superior motor development depends on the establishment of left-hemisphere dominance in intrinsic motor network connectivity.

Perturbative approach to covariance matrix of the matter power spectrum

NASA Astrophysics Data System (ADS)

Mohammed, Irshad; Seljak, Uroš; Vlah, Zvonimir

2017-04-01

We evaluate the covariance matrix of the matter power spectrum using perturbation theory up to dominant terms at 1-loop order and compare it to numerical simulations. We decompose the covariance matrix into the disconnected (Gaussian) part, trispectrum from the modes outside the survey (supersample variance) and trispectrum from the modes inside the survey, and show how the different components contribute to the overall covariance matrix. We find the agreement with the simulations is at a 10 per cent level up to k ˜ 1 h Mpc-1. We show that all the connected components are dominated by the large-scale modes (k < 0.1 h Mpc-1), regardless of the value of the wave vectors k, k΄ of the covariance matrix, suggesting that one must be careful in applying the jackknife or bootstrap methods to the covariance matrix. We perform an eigenmode decomposition of the connected part of the covariance matrix, showing that at higher k, it is dominated by a single eigenmode. The full covariance matrix can be approximated as the disconnected part only, with the connected part being treated as an external nuisance parameter with a known scale dependence, and a known prior on its variance for a given survey volume. Finally, we provide a prescription for how to evaluate the covariance matrix from small box simulations without the need to simulate large volumes.

Fast Reduction Method in Dominance-Based Information Systems

NASA Astrophysics Data System (ADS)

Li, Yan; Zhou, Qinghua; Wen, Yongchuan

2018-01-01

In real world applications, there are often some data with continuous values or preference-ordered values. Rough sets based on dominance relations can effectively deal with these kinds of data. Attribute reduction can be done in the framework of dominance-relation based approach to better extract decision rules. However, the computational cost of the dominance classes greatly affects the efficiency of attribute reduction and rule extraction. This paper presents an efficient method of computing dominance classes, and further compares it with traditional method with increasing attributes and samples. Experiments on UCI data sets show that the proposed algorithm obviously improves the efficiency of the traditional method, especially for large-scale data.

Mechanisms of nutrient retention and its relation to flow connectivity in river-floodplain corridors

USGS Publications Warehouse

Larsen, Laurel; Harvey, Judson; Maglio, Morgan M.

2015-01-01

Understanding heterogeneity or patchiness in the distribution of vegetation and retention of C and nutrients in river corridors is critical for setting priorities for river management and restoration. Several mechanisms of spatial differentiation in nutrient retention in river and floodplain corridors have been recognized, but few studies have distinguished their relative importance or established their role in long-term geomorphic change, nutrient retention, and connectivity with downstream systems. We evaluated the ability of 3 mechanisms (evapotranspiration focusing [EF], differential hydrologic exchange [DHE], and particulate nutrient redistribution [PNR]) to explain spatial patterns of P retention and function in the Everglades (Florida, USA). We used field measurements in sloughs and on slightly higher, more densely vegetated ridges to quantify P fluxes attributable to the 3 mechanisms. EF does not explain Everglades nutrient retention or P concentrations on ridges and in sloughs. However, DHE resulting from different periods of groundwater–surface-water connectivity across topographic elements is the primary cause of elevated P concentrations on ridges and completely explains interpatch differences in long-term P accumulation rates. With historical flow velocities, which were an order of magnitude higher than at present, PNR would have further increased the interpatch difference in long-term P retention rates nearly 2-fold. In conclusion, DHE and PNR are the dominant drivers of nutrient patchiness in the Everglades and are hypothesized to be important in P-limited river and floodplain corridors globally.

Looking for hotspots of marine metacommunity connectivity: a methodological framework

PubMed Central

Melià, Paco; Schiavina, Marcello; Rossetto, Marisa; Gatto, Marino; Fraschetti, Simonetta; Casagrandi, Renato

2016-01-01

Seascape connectivity critically affects the spatiotemporal dynamics of marine metacommunities. Understanding how connectivity patterns emerge from physically and biologically-mediated interactions is therefore crucial to conserve marine ecosystem functions and biodiversity. Here, we develop a set of biophysical models to explore connectivity in assemblages of species belonging to a typical Mediterranean community (Posidonia oceanica meadows) and characterized by different dispersing traits. We propose a novel methodological framework to synthesize species-specific results into a set of community connectivity metrics and show that spatiotemporal variation in magnitude and direction of the connections, as well as interspecific differences in dispersing traits, are key factors structuring community connectivity. We eventually demonstrate how these metrics can be used to characterize the functional role of each marine area in determining patterns of community connectivity at the basin level and to support marine conservation planning. PMID:27029563

Looking for hotspots of marine metacommunity connectivity: a methodological framework

NASA Astrophysics Data System (ADS)

Melià, Paco; Schiavina, Marcello; Rossetto, Marisa; Gatto, Marino; Fraschetti, Simonetta; Casagrandi, Renato

2016-03-01

Seascape connectivity critically affects the spatiotemporal dynamics of marine metacommunities. Understanding how connectivity patterns emerge from physically and biologically-mediated interactions is therefore crucial to conserve marine ecosystem functions and biodiversity. Here, we develop a set of biophysical models to explore connectivity in assemblages of species belonging to a typical Mediterranean community (Posidonia oceanica meadows) and characterized by different dispersing traits. We propose a novel methodological framework to synthesize species-specific results into a set of community connectivity metrics and show that spatiotemporal variation in magnitude and direction of the connections, as well as interspecific differences in dispersing traits, are key factors structuring community connectivity. We eventually demonstrate how these metrics can be used to characterize the functional role of each marine area in determining patterns of community connectivity at the basin level and to support marine conservation planning.

How to Build a Time Machine: Interfacing Hydrodynamics, Ionization Calculations and X-ray Spectral Codes for Supernova Remnants

NASA Astrophysics Data System (ADS)

Badenes, Carlos

2006-02-01

Thanks to Chandra and XMM-Newton, spatially resolved spectroscopy of SNRsin the X-ray band has become a reality. Several impressive data sets forejecta-dominated SNRs can now be found in the archives, the Cas A VLP justbeing one (albeit probably the most spectacular) example. However, it isoften hard to establish quantitative, unambiguous connections between theX-ray observations of SNRs and the dramatic events involved in a corecollapse or thermonuclear SN explosion. The reason for this is that thevery high quality of the data sets generated by Chandra and XMM for thelikes of Cas A, SNR 292.0+1.8, Tycho, and SN 1006 has surpassed our abilityto analyze them. The core of the problem is in the transient nature of theplasmas in SNRs, which results in anintimate relationship between the structure of the ejecta and AM, the SNRdynamics arising from their interaction, and the ensuing X-rayemission. Thus, the ONLY way to understand the X-ray observations ofejecta-dominated SNRs at all levels, from the spatially integrated spectrato the subarcsecond scales that can be resolved by Chandra, is to couplehydrodynamic simulations to nonequilibrium ionization (NEI) calculationsand X-ray spectral codes. I will review the basic ingredients that enterthis kind of calculations, and what are the prospects for using them tounderstand the X-ray emission from the shocked ejecta in young SNRs. Thisunderstanding (when it is possible), can turn SNRs into veritable timemachines, revealing the secrets of the titanic explosions that generatedthem hundreds of years ago.

Effects of Vegetation Composition and Trophic Structure on Pathways of Mercury Methylation in Alaskan Peatlands

NASA Astrophysics Data System (ADS)

Hines, M. E.; Zhang, L.; Barkay, T.; Krabbenhoft, D. P.; Liu, X.

2016-12-01

Methyl mercury (MeHg) can be produced by diverse microbes including syntrophs, methanogens, and fermenters, besides sulfate (SO42-, SRB) and iron- reducing bacteria. Many freshwater wetlands are deficient in electron acceptors that support the traditional respiratory pathways of methylation, yet high levels of MeHg can accumulate. To investigate methylation pathways in these wetlands and to connect these pathways with surface vegetation and microbial communities, experiments were conducted using peats from 28 sites in Alaska collected during the summer of 2015. The sites were clustered using multiple factor analysis based on pH, temp, CH4 and volatile fatty acids production rates, and surface vegetation composition. Three clusters were generated and corresponded to three trophic levels that were manifested by three pH levels (4.2, 5.3, and 5.8). Hg methylation activity in laboratory incubations was determined using the short-lived radioisotope 197Hg. In the low pH, Sphagnum fuscum dominated cluster, methylation rates were less than 0.1% day-1. Conversely, the high pH trophic cluster dominated by Carex aquatilis, Carex tenuiflora, and active syntrophy, exhibited Hg methylation rates as high as 10% day-1. In intermediate sites, rich in Sphagnum magellanicum with less Carex, a gradient in syntrophy and Hg methylation paths was observed. Amendments with SO42- showed very active sulfate reduction but no stimulation of methylation; another set of amendments with methanogenic inhibitors greatly reduced methylation rates at intermediate and high trophic clusters. These results suggested that SRB, metabolizing either syntrophically with methanogens and/or by fermentation, likely methylated Hg. While metatranscriptomics studies are being conducted to verify the role of syntrophs, fermenters, and methanogens as methylators, these incubation results revealed that Hg methylation pathways change greatly along trophic gradients with a dominance of respiratory pathways in rich fens, syntrophy dominance in intermediate sites, and fermentation dominance in poor bogs.

Atypical within- and between-hemisphere motor network functional connections in children with developmental coordination disorder and attention-deficit/hyperactivity disorder.

PubMed

McLeod, Kevin R; Langevin, Lisa Marie; Dewey, Deborah; Goodyear, Bradley G

2016-01-01

Developmental coordination disorder (DCD) and attention-deficit hyperactivity disorder (ADHD) are highly comorbid neurodevelopmental disorders; however, the neural mechanisms of this comorbidity are poorly understood. Previous research has demonstrated that children with DCD and ADHD have altered brain region communication, particularly within the motor network. The structure and function of the motor network in a typically developing brain exhibits hemispheric dominance. It is plausible that functional deficits observed in children with DCD and ADHD are associated with neurodevelopmental alterations in within- and between-hemisphere motor network functional connection strength that disrupt this hemispheric dominance. We used resting-state functional magnetic resonance imaging to examine functional connections of the left and right primary and sensory motor (SM1) cortices in children with DCD, ADHD and DCD + ADHD, relative to typically developing children. Our findings revealed that children with DCD, ADHD and DCD + ADHD exhibit atypical within- and between-hemisphere functional connection strength between SM1 and regions of the basal ganglia, as well as the cerebellum. Our findings further support the assertion that development of atypical motor network connections represents common and distinct neural mechanisms underlying DCD and ADHD. In children with DCD and DCD + ADHD (but not ADHD), a significant correlation was observed between clinical assessment of motor function and the strength of functional connections between right SM1 and anterior cingulate cortex, supplementary motor area, and regions involved in visuospatial processing. This latter finding suggests that behavioral phenotypes associated with atypical motor network development differ between individuals with DCD and those with ADHD.

Continuous subcutaneous delivery of medications for home care palliative patients-using an infusion set or a pump?

PubMed

Menahem, Sasson; Shvartzman, Pesach

2010-09-01

The purpose of this study was to evaluate safety, feasibility, and efficacy of continuous drug delivery by the subcutaneous route through a solution bag connected to an infusion set compared with an infusion pump in a home palliative care setting. Patients in need of continuous subcutaneous medication delivery for pain control, nausea, and/or vomiting were recruited. The study was designed as a double-blind, crossover study. The patient was connected to two parallel subcutaneous lines running simultaneously, connected together to a line entering the subcutaneous tissue. One line is connected to an infusion set and the other to a pump. The infusion set included a 500-cc solution bag connected to a 1.5-m plastic tube containing a drip chamber controlled by a roller clamp that is gravity driven without hyaluronidase. Active medications were randomly assigned to start in either administration method and switched after 24 h. An independent research assistant evaluated symptom control and side effects at baseline and every 24 h for 2 days using a structured questionnaire. Another independent research assistant connected the lines after adding medications and evaluated technical and clinical failures. Twenty-seven patients were recruited, and of them, 18 completed the study. Incidents in fluid administration were more common through the infusion set (18 times) compared to the pump (only twice). On the other hand, no clinical significant change was noted in the average symptom levels and side effects when medications were given through the infusion set versus the pump. No local edema or irritation was observed in either way of administration. In a home palliative care setting with a medical staff on call for 24 h, using medications for symptom control can be considered to be infused to a fluid solution bag through an infusion set instead of using a syringe driver or a pump when there is a responsible caregiver to follow up on the fluid. Subcutaneous constant drug delivery through a pump is more accurate.

Analytical and numerical investigation of bolted steel ring flange connection for offshore wind monopile foundations

NASA Astrophysics Data System (ADS)

Madsen, C. A.; Kragh-Poulsen, J.-C.; Thage, K. J.; Andreassen, M. J.

2017-12-01

The monopile foundation is the dominant solution for support of wind turbines in offshore wind farms. It is normally grouted to the transition piece which connects the foundation to the turbine. Currently, the bolted steel ring flange connection is investigated as an alternative. The monopile--transition piece connection has specific problems, such as out-of-verticality and installation damage from driving the MP into the seabed and it is not fully known how to design for these. This paper presents the status of the ongoing development work and an estimate of what still needs to be covered in order to use the connection in practice. This involves presentation of an analytical and non-linear FE analysis procedure for the monopile-transition piece connection composed of two L flanges connected with preloaded bolts. The connection is verified for ultimate and fatigue limit states based on an integrated load simulation carried out by the turbine manufacturer.

Wetland tree transpiration modified by river-floodplain connectivity

USGS Publications Warehouse

Allen, Scott T.; Krauss, Ken W.; Cochran, J. Wesley; King, Sammy L.; Keim, Richard F.

2016-01-01

Hydrologic connectivity provisions water and nutrient subsidies to floodplain wetlands and may be particularly important in floodplains with seasonal water deficits through its effects on soil moisture. In this study, we measured sapflow in 26 trees of two dominant floodplain forest species (Celtis laevigata and Quercus lyrata) at two hydrologically distinct sites in the lower White River floodplain in Arkansas, USA. Our objective was to investigate how connectivity-driven water table variations affected water use, an indicator of tree function. Meteorological variables (photosynthetically active radiation and vapor pressure deficit) were the dominant controls over water use at both sites; however, water table variations explained some site differences. At the wetter site, highest sapflow rates were during a late-season overbank flooding event, and no flood stress was apparent. At the drier site, sapflow decreased as the water table receded. The late-season flood pulse that resulted in flooding at the wetter site did not affect the water table at the drier site; accordingly, higher water use was not observed at the drier site. The species generally associated with wetter conditions (Q. lyrata) was more positively responsive to the flood pulse. Flood water subsidy lengthened the effective growing season, demonstrating ecological implications of hydrologic connectivity for alleviating water deficits that otherwise reduce function in this humid floodplain wetland.

Fault connectivity, distributed shortening, and impacts on geologic- geodetic slip rate discrepancies in the central Mojave Desert, California

NASA Astrophysics Data System (ADS)

Selander, J.; Oskin, M. E.; Cooke, M. L.; Grette, K.

2015-12-01

Understanding off-fault deformation and distribution of displacement rates associated with disconnected strike-slip faults requires a three-dimensional view of fault geometries. We address problems associated with distributed faulting by studying the Mojave segment of the East California Shear Zone (ECSZ), a region dominated by northwest-directed dextral shear along disconnected northwest- southeast striking faults. We use a combination of cross-sectional interpretations, 3D Boundary Element Method (BEM) models, and slip-rate measurements to test new hypothesized fault connections. We find that reverse faulting acts as an important means of slip transfer between strike-slip faults, and show that the impacts of these structural connections on shortening, uplift, strike-slip rates, and off-fault deformation, help to reconcile the overall strain budget across this portion of the ECSZ. In detail, we focus on the Calico and Blackwater faults, which are hypothesized to together represent the longest linked fault system in the Mojave ECSZ, connected by a restraining step at 35°N. Across this restraining step the system displays a pronounced displacement gradient, where dextral offset decreases from ~11.5 to <2 km from south to north. Cross-section interpretations show that ~40% of this displacement is transferred from the Calico fault to the Harper Lake and Blackwater faults via a set of north-dipping thrust ramps. Late Quaternary dextral slip rates follow a similar pattern, where 1.4 +0.8/-0.4 mm/yr of slip along the Calico fault south of 35°N is distributed to the Harper Lake, Blackwater, and Tin Can Alley faults. BEM model results using revised fault geometries for the Mojave ECSZ show areas of uplift consistent with contractional structures, and fault slip-rates that more closely match geologic data. Overall, revised fault connections and addition of off-fault deformation greatly reduces the discrepancy between geodetic and geologic slip rates.

Fourth Generation Undersea Warfare: Getting C2 for Undersea Connectivity Right

DTIC Science & Technology

2013-06-01

information dominance (ID) will not be realized unless undersea connectivity issues are given the same priority as the vehicles and sensors themselves. Said another way, failure to establish an effective C2 architecture in this degraded and austere environment will be a de facto surrender to the adversary’s attempts to deny access. One way in which the U.S. Navy has moved forward to address this issue is by changing the programmatic organization that supports this vehicle and sensor integration. As Executive Agent for the Navy’s undersea connectivity efforts,

Connectivity processes and riparian vegetation of the upper Paraná River, Brazil

NASA Astrophysics Data System (ADS)

Stevaux, José C.; Corradini, Fabrício A.; Aquino, Samia

2013-10-01

In fluvial systems, the relationship between a dominant variable (e.g. flood pulse) and its dependent ones (e.g. riparian vegetation) is called connectivity. This paper analyzes the connectivity elements and processes controlling riparian vegetation for a reach of the upper Paraná River (Brazil) and estimates the future changes in channel-vegetation relationship as a consequence of the managing of a large dam. The studied reach is situated 30 km downstream from the Porto Primavera Dam (construction finished in 1999). Through aerial photography (1:25,000, 1996), RGB-CBERS satellite imagery and a previous field botany survey it was possible to elaborate a map with the five major morpho-vegetation units: 1) Tree-dominated natural levee, 2) Shrubby upper floodplain, 3) Shrub-herbaceous mid floodplain, 4) Grass-herbaceous lower floodplain and 5) Shrub-herbaceous flood runoff channel units. By use of a detailed topographic survey and statistical tools each morpho-vegetation type was analyzed according to its connectivity parameters (frequency, recurrence, permanence, seasonality, potamophase, limnophase and FCQ index) in the pre- and post-dam closure periods of the historical series. Data showed that most of the morpho-vegetation units were predicted to present changes in connectivity parameters values after dam closing and the new regime could affect, in different intensity, the river ecology and particularly the riparian vegetation. The methods used in this study can be useful for dam impact studies in other South American tropical rivers.

Spatial-temporal-spectral EEG patterns of BOLD functional network connectivity dynamics

NASA Astrophysics Data System (ADS)

Lamoš, Martin; Mareček, Radek; Slavíček, Tomáš; Mikl, Michal; Rektor, Ivan; Jan, Jiří

2018-06-01

Objective. Growing interest in the examination of large-scale brain network functional connectivity dynamics is accompanied by an effort to find the electrophysiological correlates. The commonly used constraints applied to spatial and spectral domains during electroencephalogram (EEG) data analysis may leave part of the neural activity unrecognized. We propose an approach that blindly reveals multimodal EEG spectral patterns that are related to the dynamics of the BOLD functional network connectivity. Approach. The blind decomposition of EEG spectrogram by parallel factor analysis has been shown to be a useful technique for uncovering patterns of neural activity. The simultaneously acquired BOLD fMRI data were decomposed by independent component analysis. Dynamic functional connectivity was computed on the component’s time series using a sliding window correlation, and between-network connectivity states were then defined based on the values of the correlation coefficients. ANOVA tests were performed to assess the relationships between the dynamics of between-network connectivity states and the fluctuations of EEG spectral patterns. Main results. We found three patterns related to the dynamics of between-network connectivity states. The first pattern has dominant peaks in the alpha, beta, and gamma bands and is related to the dynamics between the auditory, sensorimotor, and attentional networks. The second pattern, with dominant peaks in the theta and low alpha bands, is related to the visual and default mode network. The third pattern, also with peaks in the theta and low alpha bands, is related to the auditory and frontal network. Significance. Our previous findings revealed a relationship between EEG spectral pattern fluctuations and the hemodynamics of large-scale brain networks. In this study, we suggest that the relationship also exists at the level of functional connectivity dynamics among large-scale brain networks when no standard spatial and spectral constraints are applied on the EEG data.

Identifying effective connectivity parameters in simulated fMRI: a direct comparison of switching linear dynamic system, stochastic dynamic causal, and multivariate autoregressive models

PubMed Central

Smith, Jason F.; Chen, Kewei; Pillai, Ajay S.; Horwitz, Barry

2013-01-01

The number and variety of connectivity estimation methods is likely to continue to grow over the coming decade. Comparisons between methods are necessary to prune this growth to only the most accurate and robust methods. However, the nature of connectivity is elusive with different methods potentially attempting to identify different aspects of connectivity. Commonalities of connectivity definitions across methods upon which base direct comparisons can be difficult to derive. Here, we explicitly define “effective connectivity” using a common set of observation and state equations that are appropriate for three connectivity methods: dynamic causal modeling (DCM), multivariate autoregressive modeling (MAR), and switching linear dynamic systems for fMRI (sLDSf). In addition while deriving this set, we show how many other popular functional and effective connectivity methods are actually simplifications of these equations. We discuss implications of these connections for the practice of using one method to simulate data for another method. After mathematically connecting the three effective connectivity methods, simulated fMRI data with varying numbers of regions and task conditions is generated from the common equation. This simulated data explicitly contains the type of the connectivity that the three models were intended to identify. Each method is applied to the simulated data sets and the accuracy of parameter identification is analyzed. All methods perform above chance levels at identifying correct connectivity parameters. The sLDSf method was superior in parameter estimation accuracy to both DCM and MAR for all types of comparisons. PMID:23717258

Prediction of vein connectivity using the percolation approach: model test with field data

NASA Astrophysics Data System (ADS)

Belayneh, M.; Masihi, M.; Matthäi, S. K.; King, P. R.

2006-09-01

Evaluating the uncertainty in fracture connectivity and its effect on the flow behaviour of natural fracture networks formed under in situ conditions is an extremely difficult task. One widely used probabilistic approach is to use percolation theory, which is well adapted to estimate the connectivity and conductivity of geometrical objects near the percolation threshold. In this paper, we apply scaling laws from percolation theory to predict the connectivity of vein sets exposed on the southern margin of the Bristol Channel Basin. Two vein sets in a limestone bed interbedded with shales on the limb of a rollover fold were analysed for length, spacing and aperture distributions. Eight scan lines, low-level aerial photographs and mosaics of photographs taken with a tripod were used. The analysed veins formed contemporaneously with the rollover fold during basin subsidence on the hanging wall of a listric normal fault. The first vein set, V1, is fold axis-parallel (i.e. striking ~100°) and normal to bedding. The second vein set, V2, strikes 140° and crosscuts V1. We find a close agreement in connectivity between our predictions using the percolation approach and the field data. The implication is that reasonable predictions of vein connectivity can be made from sparse data obtained from boreholes or (limited) sporadic outcrop.

Efficient generation of connectivity in neuronal networks from simulator-independent descriptions

PubMed Central

Djurfeldt, Mikael; Davison, Andrew P.; Eppler, Jochen M.

2014-01-01

Simulator-independent descriptions of connectivity in neuronal networks promise greater ease of model sharing, improved reproducibility of simulation results, and reduced programming effort for computational neuroscientists. However, until now, enabling the use of such descriptions in a given simulator in a computationally efficient way has entailed considerable work for simulator developers, which must be repeated for each new connectivity-generating library that is developed. We have developed a generic connection generator interface that provides a standard way to connect a connectivity-generating library to a simulator, such that one library can easily be replaced by another, according to the modeler's needs. We have used the connection generator interface to connect C++ and Python implementations of the previously described connection-set algebra to the NEST simulator. We also demonstrate how the simulator-independent modeling framework PyNN can transparently take advantage of this, passing a connection description through to the simulator layer for rapid processing in C++ where a simulator supports the connection generator interface and falling-back to slower iteration in Python otherwise. A set of benchmarks demonstrates the good performance of the interface. PMID:24795620

Genome-wide strategies identify downstream target genes of chick connective tissue-associated transcription factors.

PubMed

Orgeur, Mickael; Martens, Marvin; Leonte, Georgeta; Nassari, Sonya; Bonnin, Marie-Ange; Börno, Stefan T; Timmermann, Bernd; Hecht, Jochen; Duprez, Delphine; Stricker, Sigmar

2018-03-29

Connective tissues support organs and play crucial roles in development, homeostasis and fibrosis, yet our understanding of their formation is still limited. To gain insight into the molecular mechanisms of connective tissue specification, we selected five zinc-finger transcription factors - OSR1, OSR2, EGR1, KLF2 and KLF4 - based on their expression patterns and/or known involvement in connective tissue subtype differentiation. RNA-seq and ChIP-seq profiling of chick limb micromass cultures revealed a set of common genes regulated by all five transcription factors, which we describe as a connective tissue core expression set. This common core was enriched with genes associated with axon guidance and myofibroblast signature, including fibrosis-related genes. In addition, each transcription factor regulated a specific set of signalling molecules and extracellular matrix components. This suggests a concept whereby local molecular niches can be created by the expression of specific transcription factors impinging on the specification of local microenvironments. The regulatory network established here identifies common and distinct molecular signatures of limb connective tissue subtypes, provides novel insight into the signalling pathways governing connective tissue specification, and serves as a resource for connective tissue development. © 2018. Published by The Company of Biologists Ltd.

Children, Adolescents, and the Media.

PubMed

2013-11-01

Media, from television to the "new media" (including cell phones, iPads, and social media), are a dominant force in children's lives. Although television is still the predominant medium for children and adolescents, new technologies are increasingly popular. The American Academy of Pediatrics continues to be concerned by evidence about the potential harmful effects of media messages and images; however, important positive and prosocial effects of media use should also be recognized. Pediatricians are encouraged to take a media history and ask 2 media questions at every well-child visit: How much recreational screen time does your child or teenager consume daily? Is there a television set or Internet-connected device in the child's bedroom? Parents are encouraged to establish a family home use plan for all media. Media influences on children and teenagers should be recognized by schools, policymakers, product advertisers, and entertainment producers. Copyright © 2013 by the American Academy of Pediatrics.

Significant Atmospheric Aerosol Pollution Caused by World Food Cultivation

NASA Technical Reports Server (NTRS)

Bauer, Susanne E.; Tsigaridis, Kostas; Miller, Ron

2016-01-01

Particulate matter is a major concern for public health, causing cancer and cardiopulmonary mortality. Therefore, governments in most industrialized countries monitor and set limits for particulate matter. To assist policy makers, it is important to connect the chemical composition and severity of particulate pollution to its sources. Here we show how agricultural practices, livestock production, and the use of nitrogen fertilizers impact near-surface air quality. In many densely populated areas, aerosols formed from gases that are released by fertilizer application and animal husbandry dominate over the combined contributions from all other anthropogenic pollution. Here we test reduction scenarios of combustion-based and agricultural emissions that could lower air pollution. For a future scenario, we find opposite trends, decreasing nitrate aerosol formation near the surface while total tropospheric loads increase. This suggests that food production could be increased to match the growing global population without sacrificing air quality if combustion emission is decreased.

Efficient receptive field tiling in primate V1

PubMed Central

Nauhaus, Ian; Nielsen, Kristina J.; Callaway, Edward M.

2017-01-01

The primary visual cortex (V1) encodes a diverse set of visual features, including orientation, ocular dominance (OD) and spatial frequency (SF), whose joint organization must be precisely structured to optimize coverage within the retinotopic map. Prior experiments have only identified efficient coverage based on orthogonal maps. Here, we used two-photon calcium imaging to reveal an alternative arrangement for OD and SF maps in macaque V1; their gradients run parallel but with unique spatial periods, whereby low SF regions coincide with monocular regions. Next, we mapped receptive fields and find surprisingly precise micro-retinotopy that yields a smaller point-image and requires more efficient inter-map geometry, thus underscoring the significance of map relationships. While smooth retinotopy is constraining, studies suggest that it improves both wiring economy and the V1 population code read downstream. Altogether, these data indicate that connectivity within V1 is finely tuned and precise at the level of individual neurons. PMID:27499086

Learning through ferroelectric domain dynamics in solid-state synapses

NASA Astrophysics Data System (ADS)

Boyn, Sören; Grollier, Julie; Lecerf, Gwendal; Xu, Bin; Locatelli, Nicolas; Fusil, Stéphane; Girod, Stéphanie; Carrétéro, Cécile; Garcia, Karin; Xavier, Stéphane; Tomas, Jean; Bellaiche, Laurent; Bibes, Manuel; Barthélémy, Agnès; Saïghi, Sylvain; Garcia, Vincent

2017-04-01

In the brain, learning is achieved through the ability of synapses to reconfigure the strength by which they connect neurons (synaptic plasticity). In promising solid-state synapses called memristors, conductance can be finely tuned by voltage pulses and set to evolve according to a biological learning rule called spike-timing-dependent plasticity (STDP). Future neuromorphic architectures will comprise billions of such nanosynapses, which require a clear understanding of the physical mechanisms responsible for plasticity. Here we report on synapses based on ferroelectric tunnel junctions and show that STDP can be harnessed from inhomogeneous polarization switching. Through combined scanning probe imaging, electrical transport and atomic-scale molecular dynamics, we demonstrate that conductance variations can be modelled by the nucleation-dominated reversal of domains. Based on this physical model, our simulations show that arrays of ferroelectric nanosynapses can autonomously learn to recognize patterns in a predictable way, opening the path towards unsupervised learning in spiking neural networks.

Therapeutic friendliness and the development of therapeutic leverage by mental health nurses in community rehabilitation settings.

PubMed

Gardner, Andrew

2010-01-01

In a world dominated by technology and driven by fiscal policy emphasis, the therapeutic relationship as a healing modality is still a central theme to mental health nurses (MHN) in their everyday work. This research, as part of a PhD program, used a constructivist grounded theory approach to explore the process of therapeutic relationships and professional boundaries. The current paper outlines how therapeutic friendliness provides a connection for the therapeutic relationship to develop but in doing so requires a balancing of the therapeutic relationship and constant maintenance of the professional boundary. The authors also discuss how community mental health nurses (CMHN) invest in the therapeutic relationship in order to develop a therapeutic alliance and how the alliance between the CMHN and the client facilitates the use of therapeutic leverage applied by the CMHN as part of the therapeutic process.

First endemic freshwater Gammarus from Crete and its evolutionary history-an integrative taxonomy approach.

PubMed

Hupało, Kamil; Mamos, Tomasz; Wrzesińska, Weronika; Grabowski, Michał

2018-01-01

The Mediterranean islands are known as natural laboratories of evolution with a high level of endemic biodiversity. However, most biodiversity assessments have focused mainly on terrestrial and marine fauna, leaving the freshwater animals aside. Crete is one of the largest islands in the Mediterranean Basin, with a long history of isolation from the continental mainland. Gammarid amphipods are often dominant in macrozoobenthic communities in European inland waters. They are widely used in biomonitoring and exotoxicological studies. Herein, we describe Gammarus plaitisi sp. nov., endemic to Cretan streams, based on morphological characters and a set of molecular species delimitation methods using mitochondrial cytochrome oxidase subunit I and 16S rRNA genes as well as nuclear 28S rDNA, ITS1 and EF1-alpha genes. The divergence of the new species is strongly connected with the geological history of the island supporting its continental origin.

Significant atmospheric aerosol pollution caused by world food cultivation

NASA Astrophysics Data System (ADS)

Bauer, Susanne E.; Tsigaridis, Kostas; Miller, Ron

2016-05-01

Particulate matter is a major concern for public health, causing cancer and cardiopulmonary mortality. Therefore, governments in most industrialized countries monitor and set limits for particulate matter. To assist policy makers, it is important to connect the chemical composition and severity of particulate pollution to its sources. Here we show how agricultural practices, livestock production, and the use of nitrogen fertilizers impact near-surface air quality. In many densely populated areas, aerosols formed from gases that are released by fertilizer application and animal husbandry dominate over the combined contributions from all other anthropogenic pollution. Here we test reduction scenarios of combustion-based and agricultural emissions that could lower air pollution. For a future scenario, we find opposite trends, decreasing nitrate aerosol formation near the surface while total tropospheric loads increase. This suggests that food production could be increased to match the growing global population without sacrificing air quality if combustion emission is decreased.

Significant atmospheric aerosol pollution caused by world food cultivation

NASA Astrophysics Data System (ADS)

Bauer, Susanne E.; Tsigaridis, Kostas; Miller, Ron

2017-04-01

Particulate matter is a major concern for public health, causing cancer and cardiopulmonary mortality. Therefore, governments in most industrialized countries monitor and set limits for particulate matter. To assist policy makers, it is important to connect the chemical composition and severity of particulate pollution to it s sources. Here we show how agricultural practices, livestock production, and the use of nitrogen fertilizers impact near-surface air quality. In many densely populated areas, aerosols formed from gases that are released by fertilizer application and animal husbandry dominate over the combined contributions from all other anthropogenic pollution. Here we test reduction scenarios of combustion-based and agricultural emissions that could lower air pollution. For a future scenario, we find opposite trends, decreasing nitrate aerosol formation near the surface while total tropospheric loads increase. This suggests that food production could be increased to match the growing global population without sacrificing air quality if combustion emission is decreased.

Rare co-occurrence of osteogenesis imperfecta type I and autosomal dominant polycystic kidney disease.

PubMed

Hoefele, Julia; Mayer, Karin; Marschall, Christoph; Alberer, Martin; Klein, Hanns-Georg; Kirschstein, Martin

2016-11-01

There are several clinical reports about the co-occurrence of autosomal dominant polycystic kidney disease (ADPKD) and connective tissue disorders. A simultaneous occurrence of osteogenesis imperfecta (OI) type I and ADPKD has not been observed so far. This report presents the first patient with OI type I and ADPKD. Mutational analysis of PKD1 and COL1A1 in the index patient revealed a heterozygous mutation in each of the two genes. Mutational analysis of the parents indicated the mother as a carrier of the PKD1 mutation and the father as a carrier of the COL1A1 mutation. The simultaneous occurrence of both disorders has an estimated frequency of 3.5:100 000 000. In singular cases, ADPKD can occur in combination with other rare disorders, e.g. connective tissue disorders.

Perturbative approach to covariance matrix of the matter power spectrum

DOE PAGES

Mohammed, Irshad; Seljak, Uros; Vlah, Zvonimir

2016-12-14

Here, we evaluate the covariance matrix of the matter power spectrum using perturbation theory up to dominant terms at 1-loop order and compare it to numerical simulations. We decompose the covariance matrix into the disconnected (Gaussian) part, trispectrum from the modes outside the survey (beat coupling or super-sample variance), and trispectrum from the modes inside the survey, and show how the different components contribute to the overall covariance matrix. We find the agreement with the simulations is at a 10\\% level up tomore » $$k \\sim 1 h {\\rm Mpc^{-1}}$$. We also show that all the connected components are dominated by the large-scale modes ($$k<0.1 h {\\rm Mpc^{-1}}$$), regardless of the value of the wavevectors $$k,\\, k'$$ of the covariance matrix, suggesting that one must be careful in applying the jackknife or bootstrap methods to the covariance matrix. We perform an eigenmode decomposition of the connected part of the covariance matrix, showing that at higher $k$ it is dominated by a single eigenmode. Furthermore, the full covariance matrix can be approximated as the disconnected part only, with the connected part being treated as an external nuisance parameter with a known scale dependence, and a known prior on its variance for a given survey volume. Finally, we provide a prescription for how to evaluate the covariance matrix from small box simulations without the need to simulate large volumes.« less

Will it Blend? Visualization and Accuracy Evaluation of High-Resolution Fuzzy Vegetation Maps

NASA Astrophysics Data System (ADS)

Zlinszky, A.; Kania, A.

2016-06-01

Instead of assigning every map pixel to a single class, fuzzy classification includes information on the class assigned to each pixel but also the certainty of this class and the alternative possible classes based on fuzzy set theory. The advantages of fuzzy classification for vegetation mapping are well recognized, but the accuracy and uncertainty of fuzzy maps cannot be directly quantified with indices developed for hard-boundary categorizations. The rich information in such a map is impossible to convey with a single map product or accuracy figure. Here we introduce a suite of evaluation indices and visualization products for fuzzy maps generated with ensemble classifiers. We also propose a way of evaluating classwise prediction certainty with "dominance profiles" visualizing the number of pixels in bins according to the probability of the dominant class, also showing the probability of all the other classes. Together, these data products allow a quantitative understanding of the rich information in a fuzzy raster map both for individual classes and in terms of variability in space, and also establish the connection between spatially explicit class certainty and traditional accuracy metrics. These map products are directly comparable to widely used hard boundary evaluation procedures, support active learning-based iterative classification and can be applied for operational use.

Comparison of image segmentation of lungs using methods: connected threshold, neighborhood connected, and threshold level set segmentation

NASA Astrophysics Data System (ADS)

Amanda, A. R.; Widita, R.

2016-03-01

The aim of this research is to compare some image segmentation methods for lungs based on performance evaluation parameter (Mean Square Error (MSE) and Peak Signal Noise to Ratio (PSNR)). In this study, the methods compared were connected threshold, neighborhood connected, and the threshold level set segmentation on the image of the lungs. These three methods require one important parameter, i.e the threshold. The threshold interval was obtained from the histogram of the original image. The software used to segment the image here was InsightToolkit-4.7.0 (ITK). This research used 5 lung images to be analyzed. Then, the results were compared using the performance evaluation parameter determined by using MATLAB. The segmentation method is said to have a good quality if it has the smallest MSE value and the highest PSNR. The results show that four sample images match the criteria of connected threshold, while one sample refers to the threshold level set segmentation. Therefore, it can be concluded that connected threshold method is better than the other two methods for these cases.

Spatial part-set cuing facilitation.

PubMed

Kelley, Matthew R; Parasiuk, Yuri; Salgado-Benz, Jennifer; Crocco, Megan

2016-07-01

Cole, Reysen, and Kelley [2013. Part-set cuing facilitation for spatial information. Journal of Experimental Psychology: Learning, Memory, & Cognition, 39, 1615-1620] reported robust part-set cuing facilitation for spatial information using snap circuits (a colour-coded electronics kit designed for children to create rudimentary circuit boards). In contrast, Drinkwater, Dagnall, and Parker [2006. Effects of part-set cuing on experienced and novice chess players' reconstruction of a typical chess midgame position. Perceptual and Motor Skills, 102(3), 645-653] and Watkins, Schwartz, and Lane [1984. Does part-set cuing test for memory organization? Evidence from reconstructions of chess positions. Canadian Journal of Psychology/Revue Canadienne de Psychologie, 38(3), 498-503] showed no influence of part-set cuing for spatial information when using chess boards. One key difference between the two procedures was that the snap circuit stimuli were explicitly connected to one another, whereas chess pieces were not. Two experiments examined the effects of connection type (connected vs. unconnected) and cue type (cued vs. uncued) on memory for spatial information. Using chess boards (Experiment 1) and snap circuits (Experiment 2), part-set cuing facilitation only occurred when the stimuli were explicitly connected; there was no influence of cuing with unconnected stimuli. These results are potentially consistent with the retrieval strategy disruption hypothesis, as well as the two- and three-mechanism accounts of part-set cuing.

Does stability in local community composition depend on temporal variation in rates of dispersal and connectivity?

NASA Astrophysics Data System (ADS)

Valanko, Sebastian; Norkko, Joanna; Norkko, Alf

2015-04-01

In ecology understanding variation in connectivity is central for how biodiversity is maintained. Field studies on dispersal and temporal dynamics in community regulating processes are, however, rare. We test the short-term temporal stability in community composition in a soft-sediment benthic community by determining among-sampling interval similarity in community composition. We relate stability to in situ measures of connectivity (wind, wave, current energy) and rates of dispersal (quantified in different trap types). Waves were an important predictor of when local community taxa are most likely to disperse in different trap-types, suggesting that wave energy is important for connectivity in a region. Community composition at the site was variable and changed stochastically over time. We found changes in community composition (occurrence, abundance, dominance) to be greater at times when connectivity and rates of dispersal were low. In response to periods of lower connectedness dominant taxa in the local community only exhibited change in their relative abundance. In contrast, locally less abundant taxa varied in both their presence, as well as in relative abundance. Constancy in connectivity and rates of dispersal promotes community stability and persistence, suggesting that local community composition will be impacted by changes in the spatial extent over which immigration and emigration operates in the region. Few empirical studies have actually measured dispersal directly in a multi-species context to demonstrate the role it plays in maintaining local community structure. Even though our study does not evaluate coexistence over demographic time scales, it importantly demonstrates that dispersal is not only important in initial recruitment or following a disturbance, but also key in maintaining local community composition.

A long-term data set for hydrologic modeling in a snow-dominated mountain catchment

USDA-ARS?s Scientific Manuscript database

An hourly modeling data set is presented for the water years 1984 through 2008 for a snow-dominated headwater catchment. Meteorological forcing data and GIS watershed characteristics are described and provided. The meteorological data are measured at two sites within the catchment, and include pre...

Organizing principles for the cerebral cortex network of commissural and association connections.

PubMed

Swanson, Larry W; Hahn, Joel D; Sporns, Olaf

2017-11-07

Cognition is supported by a network of axonal connections between gray matter regions within and between right and left cerebral cortex. Global organizing principles of this circuitry were examined with network analysis tools applied to monosynaptic association (within one side) and commissural (between sides) connections between all 77 cortical gray matter regions in each hemisphere of the rat brain. The analysis used 32,350 connection reports expertly collated from published pathway tracing experiments, and 5,394 connections of a possible 23,562 were identified, for a connection density of 23%-of which 20% (1,084) were commissural. Network community detection yielded a stable bihemispheric six-module solution, with an identical set in each hemisphere of three modules topographically forming a lateral core and medial shell arrangement of cortical regions. Functional correlations suggest the lateral module deals preferentially with environmental sensory-motor interactions and the ventromedial module deals preferentially with visceral control, affect, and short-term memory, whereas the dorsomedial module resembles the default mode network. Analysis of commissural connections revealed a set of unexpected rules to help generate hypotheses. Most notably, there is an order of magnitude more heterotopic than homotopic projections; all cortical regions send more association than commissural connections, and for each region, the latter are always a subset of the former; the number of association connections from each cortical region strongly correlates with the number of its commissural connections; and the module (dorsomedial) lying closest to the corpus callosum has the most complete set of commissural connections-and apparently the most complex function. Copyright © 2017 the Author(s). Published by PNAS.

Why should we pay more for layout designers?

NASA Astrophysics Data System (ADS)

Khan, Samee U.

2003-12-01

In this paper, we discuss the Passive Optical Network (PON) deployment on an arbitrary grid with guarenteed p-1 equipment failure. We show that this problem in general is NP-hard. We propose an algorithm, which guarantees a solution of 4-approximation to the optimal deployment, and further argue that this is the best lower bound achievable in our case.A basic architecture of PON is shown in figure 1.The main component of PON is an optical splitter device. Depending on which direction the light is travelling, it splits the incoming light and distributes it to multiple fibers towards Optical Network Termination (ONT), or combines it into one towards Optical Line Terminal (OLT). The PON technology uses a double-star architecture. The first star topology centers at the OLT, and the second at the optical splitter. PROBLEM DESCRIPTION: We can formulate the problem of optimal p-1 fault-tolerent PON Network Layout (PNL)as a graph theoretical problem. Consider a graph G(V,E), such that V represent the physical locations of the subscriber's, CO, and another location acquired by the CO to expand its network, and E represent the communication lines between two Vi's. If there is no direct communication line c(i,j) between Vi and Vj, we consider the shortest path between them measured in terms of simple distance or cost constraints. Without the loss of generality we assume that c(i,j)=c(j,i). For simplicity we do not further sub-divide V into the obvious categories that represent the locations of OLT, ONT, CO, optical splitters and the subscribers. We can now formulate the PNL problem as follows: "Given an undirected graph G, find the locations of ONTs and splitters such that the cost of the equipment is minimized and for QoS the maximum distance from an ONT to the pth splitter and from a splitter to the pth OLT is minimized". We assume that the OLT is residing inside the CO. The problem definition does not consider the optimization of ONT to the customer premises. This is due to the fact that the distance from ONT to the premises is negligibly small, and fault tolerance for a failed ONT can be answered by replacing the connection from a nearby ONT. We will treat ONT and ONU as more or less the same entity. GENERALIZED PNL IS NP-Hard: Essentially our problem definition consists of two major optimization steps, i.e. ONT to splitters and splitters to the OLT. Showing the hardness of the problem over one optimization step would be sufficient to show that the over all the problem is hard. If we consider the optimization of the first phase of the problem, i.e. minimize the maximum distance of ONTs to the splitters and reduce the cost of the equipment, this can be solved by associating cost to vertices V (equipment cost) and edges E (fiber cost). Thus the problem reduces to finding the smallest number of minimum cost edges from a splitter to an ONT, such that the chosen set of edges identify vertices that connect in a min-max fashion. Lemma 1 Let U be maximal k-independent set such that |U|>=k, then U is a k-dominating set in G^2. Proof (follows form def 1&2) Lemma 2 Let V be a k-dominating set in G, then |U|<=|V| holds for any k-independent set U in G^2. Proof For the two non-trivial cases of U subset V, a) U is not contained in V. Pick a node u at random such that u belongs U-V. Thus a set of nodes S can be defined such that the neighborhood of u N(u) is not contained in V, i.e. S=N(u) intersection V. Let L define the set of nodes that are adjacent to S, then any node v in SUL is contained in G^2 (definition 2) and is adjacent to at most k vertices in SUL. b) U is contained in V. If U is contained in V, then we can define a graph G containing vertices V-(SUL). Thus the lemma would hold, if V'=V-(SUL)=V-S, where V' is a k-dominating set in G. Pick a random node v in G not contained in V, then v belongs to V-V', and v has atleast k neighbors in G not present in V'. Since we assumed that V' is a k-dominating set in G, no neighbor belongs to G (by definition of G). Thus N(v) intersection V' is a subset of V'. Theorem 1 Assuming P!=NP, for any arbitrary fixed a<=p, there does not exist any polynomial time algorithm for PNL. Proof Suppose we have an algorithm A, which gives a solution for the PNL problem, then a solution for dominating set can be obtained. We will now give a polynomial time reduction from PNL to the dominating set problem. Let |V| be the pairwise neighborhood graph such that by picking any vertex v in V, N(v) intersection V is null. Thus the graph to find PNL (figure 2) can be computed by picking vertices as follows:(u,v)= 1 if u,v belongs V(u,v)= 1 if u belongs V and n belongs N(v) (u,v)= f(|V|)+ epsilon otherwise The choice of epsilon, exhibits the epsilon approximation factor in the final layout. If G has the dominating set of size d, then the solution for PNL has a set J such that dUN(v) is a set of nodes with cardinality d+(a-1), where a<=p. For a=1, the problem reduces to minimum k-center problem, so we will consider a>=2. Pick any node v in N(v). It is clear that v has only one neighbor in V', which is at a distance of 1 (triangle inequality). If it is not equal to 1, then it must be covered by a neibours within a distance of 1. Let Z=P intersection V such that Z is subset of V and contains d nodes such that d=|P|-(a-1)|V|, then any arbitrary node v belongs to V-Z must have atleast a nodes in P with a adistance of 1, but by definition and previous argument, only a-1 nodes can form the neighborhood. Thus, Z is a dominating set of size d, but by lemma 2, G cannot contain a dominating set of size d. OUR APPROACH: We assume that the edges of the graph G have the triangle inequality property. Let Si represent the set of weighted vertices w(v) such that once picked, they form a clique in graph G. PNL Algorithm Input: G Output: G' (Final PNL) 1. Construct G1^2,G2^2,....,Gm^2 2. Compute I, (Mi) in each Gi^2 3. Find the smallest index i, such that |Mi|<=k, say Mj 4. Input Mj for step 5. 5. Construct G1j^2,G2j^2,....,Gmj^2 6. Compute I, (Mij) in each Gij^2 7. Compute Si=si(u)|u belongs to Mij 8. Find the minimum index i such that w(Si)<= w(D) 9. Return Sj 10. Compute G'=min Mij belongs V [max si sum{i=0}^{|Sj|] 11. Return G' Theorem 2 The PNL algorithm is complete and will identify a solution, if there exists one. Proof (Trivial and not included due to space) Theorem 3 The PNL algorithm has a lower bound of 4-approximation to the optimal algorithm. Proof (Not included due to space, but the basic argument, is due to the fact that picking a node v with 2-epsilon in G^2, would required the neighbors to be picked in G^4, thus the PNL is no better than 4-epsilon, where epsilon >0) Experiments We made some initial experiments, which are showing promissing results with savings in fiber, equipment cost, due to space, and inital phase of the experiments, we are not including the results here. P.S. My appologies for exceeding the text limit. There is much more detail to the formal proof, I hope the idea is still conveyed. There are also 2 figures which will be faxed.

DirtyGrid I: 3D Dust Radiative Transfer Modeling of Spectral Energy Distributions of Dusty Stellar Populations

NASA Astrophysics Data System (ADS)

Law, Ka-Hei; Gordon, Karl D.; Misselt, Karl A.

2018-06-01

Understanding the properties of stellar populations and interstellar dust has important implications for galaxy evolution. In normal star-forming galaxies, stars and the interstellar medium dominate the radiation from ultraviolet (UV) to infrared (IR). In particular, interstellar dust absorbs and scatters UV and optical light, re-emitting the absorbed energy in the IR. This is a strongly nonlinear process that makes independent studies of the UV-optical and IR susceptible to large uncertainties and degeneracies. Over the years, UV to IR spectral energy distribution (SED) fitting utilizing varying approximations has revealed important results on the stellar and dust properties of galaxies. Yet the approximations limit the fidelity of the derived properties. There is sufficient computer power now available that it is now possible to remove these approximations and map out of landscape of galaxy SEDs using full dust radiative transfer. This improves upon previous work by directly connecting the UV, optical, and IR through dust grain physics. We present the DIRTYGrid, a grid of radiative transfer models of SEDs of dusty stellar populations in galactic environments designed to span the full range of physical parameters of galaxies. Using the stellar and gas radiation input from the stellar population synthesis model PEGASE, our radiative transfer model DIRTY self-consistently computes the UV to far-IR/sub-mm SEDs for each set of parameters in our grid. DIRTY computes the dust absorption, scattering, and emission from the local radiation field and a dust grain model, thereby physically connecting the UV-optical to the IR. We describe the computational method and explain the choices of parameters in DIRTYGrid. The computation took millions of CPU hours on supercomputers, and the SEDs produced are an invaluable tool for fitting multi-wavelength data sets. We provide the complete set of SEDs in an online table.

Connecting apparatus for limited rotary of rectilinear motion (II)

DOEpatents

Hardin, Jr., Roy T.; Kurinko, Carl D.

1981-01-01

Apparatus for providing connection between two members having relative movement in a horizontal plane in a rotary or linear fashion. The apparatus includes a set of vertical surfaces affixed to each of the members, laterally aligned across a selected vertical gap. A number of cables or hoses, for electrical, hydraulic, or pneumatic connection are arranged between consecutive surfaces in a C-shaped traveling loop, connected through their end portions to the two respective members, so that through a sliding motion portions of the cable are transferred from between one set of surfaces to the other aligned set, across the gap, upon relative motion of the members. A number of flexible devices are affixed to the upper set of surfaces for supporting the upper portion of each looped cable. The apparatus is particularly adaptable to an area having limited lateral clearances and requiring signal level separation between electrical cables, such as found in the rotating plugs and associated equipment of the reactor vessel head of a nuclear reactor.

Microbial community changes with decaying chloramine residuals in a lab-scale system.

PubMed

Bal Krishna, K C; Sathasivan, Arumugam; Ginige, Maneesha P

2013-09-01

When chloramine is used as a disinfectant, managing an acceptable "residual" throughout the water distribution systems particularly once nitrification has set in is challenging. Managing chloramine decay prior to the onset of nitrification through effective control strategies is important and to-date the strategies developed around nitrification has been ineffective. This study aimed at developing a more holistic knowledge on how decaying chloramine and nitrification metabolites impact microbial communities in chloraminated systems. Five lab-scale reactors (connected in series) were operated to simulate a full-scale chloraminated distribution system. Culture independent techniques (cloning and qPCR) were used to characterise and quantify the mixed microbial communities in reactors maintaining a residual of high to low (2.18-0.03 mg/L). The study for the first time associates chloramine residuals and nitrification metabolites to different microbial communities. Bacterial classes Solibacteres, Nitrospira, Sphingobacteria and Betaproteobacteria dominated at low chloramine residuals whereas Actinobacteria and Gammaproteobacteria dominated at higher chloramine residuals. Prior to the onset of nitrification bacterial genera Pseudomonas, Methylobacterium and Sphingomonas were found to be dominant and Sphingomonas in particular increased with the onset of nitrification. Nitrosomonas urea, oligotropha, and two other novel ammonia-oxidizing bacteria were detected once the chloramine residuals had dropped below 0.65 mg/L. Additionally nitrification alone failed to explain chloramine decay rates observed in these reactors. The finding of this study is expected to re-direct the focus from nitrifiers to heterotrophic bacteria, which the authors believe could hold the key towards developing a control strategy that would enable better management of chloramine residuals. Copyright © 2013 Elsevier Ltd. All rights reserved.

Elimination of spiral waves in a locally connected chaotic neural network by a dynamic phase space constraint.

PubMed

Li, Yang; Oku, Makito; He, Guoguang; Aihara, Kazuyuki

2017-04-01

In this study, a method is proposed that eliminates spiral waves in a locally connected chaotic neural network (CNN) under some simplified conditions, using a dynamic phase space constraint (DPSC) as a control method. In this method, a control signal is constructed from the feedback internal states of the neurons to detect phase singularities based on their amplitude reduction, before modulating a threshold value to truncate the refractory internal states of the neurons and terminate the spirals. Simulations showed that with appropriate parameter settings, the network was directed from a spiral wave state into either a plane wave (PW) state or a synchronized oscillation (SO) state, where the control vanished automatically and left the original CNN model unaltered. Each type of state had a characteristic oscillation frequency, where spiral wave states had the highest, and the intra-control dynamics was dominated by low-frequency components, thereby indicating slow adjustments to the state variables. In addition, the PW-inducing and SO-inducing control processes were distinct, where the former generally had longer durations but smaller average proportions of affected neurons in the network. Furthermore, variations in the control parameter allowed partial selectivity of the control results, which were accompanied by modulation of the control processes. The results of this study broaden the applicability of DPSC to chaos control and they may also facilitate the utilization of locally connected CNNs in memory retrieval and the exploration of traveling wave dynamics in biological neural networks. Copyright © 2017 Elsevier Ltd. All rights reserved.

[Topological models of retention index of thin-layer chromatogram for chiral organic acids].

PubMed

Li, Mingjian; Wang, Yuxiao; Feng, Hui; Feng, Changjun

2014-03-01

On the basis of Kier's molecular connectivity indices and conjugated matrix, novel molecular connectivity indices ((m) G(t)(v)) were defined and calculated for 18 chiral hydroxyl acids and amino acids. The chiral connectivity indices ((m)C(t)(v)) were introduced by extending (m)G(t)(v): (m)C(t)(v) = (m)G(t)(v) x w(j), where w(j) is the chiral index. The quantitative structure-retention index relationship (QSRR) between the retention index (R(M)) of thin-layer chromatogram for the chiral organic acids and (m)C(t)(v) was studied by multivariate statistical regression. By leaps-and-bounds regression analysis, the best four-parameter QSRR model was set up, and the traditional correlation coefficient (R2) and the cross-validation correlation coefficient (Q2) of leave-one-out (LOO) were 0.973 and 0.950, respectively. The results demonstrated that the model was highly reliable and had good predictive ability from the point of view of statistics. From the four parameters (0C(p)(v), 2C(p)(v), C(ch),(v), 5C(p)(v)) of the model, it is known that the dominant influence factors of the retention index were the molecular structure characteristics of two-dimensional and the space factors: the chiral characteristics, the flexibility and the puckered degree of molecules for the chiral organic acids. The results showed that the new parameter mC(t)(v) had good rationality and efficiency for the retention indices of the chiral organic acids. Therefore, an effective method was provided to predict the retention indices of the chiral organic acids.

A New Kinematic Model for Polymodal Faulting: Implications for Fault Connectivity

NASA Astrophysics Data System (ADS)

Healy, D.; Rizzo, R. E.

2015-12-01

Conjugate, or bimodal, fault patterns dominate the geological literature on shear failure. Based on Anderson's (1905) application of the Mohr-Coulomb failure criterion, these patterns have been interpreted from all tectonic regimes, including normal, strike-slip and thrust (reverse) faulting. However, a fundamental limitation of the Mohr-Coulomb failure criterion - and others that assume faults form parallel to the intermediate principal stress - is that only plane strain can result from slip on the conjugate faults. However, deformation in the Earth is widely accepted as being three-dimensional, with truly triaxial stresses and strains. Polymodal faulting, with three or more sets of faults forming and slipping simultaneously, can generate three-dimensional strains from truly triaxial stresses. Laboratory experiments and outcrop studies have verified the occurrence of the polymodal fault patterns in nature. The connectivity of polymodal fault networks differs significantly from conjugate fault networks, and this presents challenges to our understanding of faulting and an opportunity to improve our understanding of seismic hazards and fluid flow. Polymodal fault patterns will, in general, have more connected nodes in 2D (and more branch lines in 3D) than comparable conjugate (bimodal) patterns. The anisotropy of permeability is therefore expected to be very different in rocks with polymodal fault patterns in comparison to conjugate fault patterns, and this has implications for the development of hydrocarbon reservoirs, the genesis of ore deposits and the management of aquifers. In this contribution, I assess the published evidence and models for polymodal faulting before presenting a novel kinematic model for general triaxial strain in the brittle field.

Diagnostic Exome Sequencing Identifies a Novel Gene, EMILIN1, Associated with Autosomal-Dominant Hereditary Connective Tissue Disease.

PubMed

Capuano, Alessandra; Bucciotti, Francesco; Farwell, Kelly D; Tippin Davis, Brigette; Mroske, Cameron; Hulick, Peter J; Weissman, Scott M; Gao, Qingshen; Spessotto, Paola; Colombatti, Alfonso; Doliana, Roberto

2016-01-01

Heritable connective tissue diseases are a highly heterogeneous family of over 200 disorders that affect the extracellular matrix. While the genetic basis of several disorders is established, the etiology has not been discovered for a large portion of patients, likely due to rare yet undiscovered disease genes. By performing trio-exome sequencing of a 55-year-old male proband presenting with multiple symptoms indicative of a connective disorder, we identified a heterozygous missense alteration in exon 1 of the Elastin Microfibril Interfacer 1 (EMILIN1) gene, c.64G>A (p.A22T). The proband presented with ascending and descending aortic aneurysms, bilateral lower leg and foot sensorimotor peripheral neuropathy, arthropathy, and increased skin elasticity. Sanger sequencing confirmed that the EMILIN1 alteration, which maps around the signal peptide cleavage site, segregated with disease in the affected proband, mother, and son. The impaired secretion of EMILIN-1 in cells transfected with the mutant p.A22T coincided with abnormal protein accumulation within the endoplasmic reticulum. In skin biopsy of the proband, we detected less EMILIN-1 with disorganized and abnormal coarse fibrils, aggregated deposits underneath the epidermis basal lamina, and dermal cells apoptosis. These findings collectively suggest that EMILIN1 may represent a new disease gene associated with an autosomal-dominant connective tissue disorder. © 2015 The Authors. **Human Mutation published by Wiley Periodicals, Inc.

Dynamic changes in functional cerebral connectivity of spatial cognition during the menstrual cycle.

PubMed

Weis, Susanne; Hausmann, Markus; Stoffers, Barbara; Sturm, Walter

2011-10-01

Functional cerebral asymmetries (FCAs) in women have been shown to vary with changing levels of sex hormones during the menstrual cycle. Previous studies have suggested that interhemispheric interaction forms a key component in generating FCAs and it has been shown behaviorally and by functional imaging that interhemispheric interaction changes during the menstrual cycle, at least for a left hemisphere dominant task. We used functional MRI and an analysis of functional connectivity to examine whether changes in right hemisphere advantage for a figure comparison task as found in behavioral studies, are based on comparable mechanisms like those identified for the verbal task. Women were examined three times during the menstrual cycle, during the menstrual, follicular and luteal phases. The behavioral data confirmed the right hemisphere advantage for the figure comparison task as well as changes of the right hemisphere advantage during the menstrual cycle. Imaging data showed cycle phase-related changes in lateralized brain activation within the task-dominant hemisphere and changes in connectivity between nonhomotopic areas of both hemispheres, suggesting that changes in functional brain organization in women during the menstrual cycle are not only restricted to hormone-related changes of interhemispheric inhibition between homotopic areas, as has been proposed earlier, but might additionally apply to changes of neuronal processes within the hemispheres which seem to be modulated by heterotopic functional connectivity between hemispheres. Copyright © 2010 Wiley-Liss, Inc.

Climatic changes in the Antarctic Eocene: - palaeontological, mineralogical and geochemical fossil proxies from bryozoans

NASA Astrophysics Data System (ADS)

Hara, Urszula

2017-04-01

The earliest Antarctic Cenozoic (late early Eocene) bryozoan fossil records, recognized in the La Meseta Fm. on Seymour Island (Antarctic Peninsula) are connected with the major K/T phase of the cheilostome evolution, clear preponderance of cerioporoidean cyclostomes along with abundant occurrence of microporoideans, umbonulomorphs and lepraliomorphs. The presence of the loose, small zooecia of the cheilostome bryozoans in the lowermost part of this formation, systematically includes the buguloids and catenicelloideans such as e.g. Beanidae, Catenicellidae, Savignyellidae and Calwelliidae families, which in the present day are widely distributed in the tropical-warm latitudes mostly in the shallow-marine settings (Hara 2015). Undoubtedly, the occurrence of over 90% of the warm-loving multilamellar cyclostomes with the relatively slow growing rate is connected with a short-term episode in the lower part of the La Meseta Formation (Telm1), during their long in situ evolution. The recently recognized biota in the middle part of the La Meseta Formation (Telm4 and Telm5) on the NE side of the Seymour Island, reveal a presence of the microporoideans of the Micropora as well as free-living lunulitiforms belonging to the Lunulites and Otionellina genera, which developed disc-shaped colonies (Hara et al. 2015, in review). They are dominated in the Telm5, along with the new umbonulomorph of the family Brydonellidae Uharella seymourensis, found as an epilithozoic, encrusting bryozoan occurring in a loose residuum of the siliciclastic sediments. Environmentally, Recent, free-living lunulitids are known to occur in warm, shallow-shelf conditions, at temperatures of 10-29˚C, on coarse, sandy to muddy bottom with low to moderate deposition in fairly high velocity current regime and they are overwhelmingly associated with sand fauna environments. The dominance of the lunulitiform colonies in the Telm4-5 may suggests the shallow-water setting in this middle part of the formation (Bartonian in age). Contrary to that, the bryozoan fauna recognized in the upper part of the LMF (Telm7) is composed of the impoverished biota of the scarse lepraliomorphs, poorly preserved cyclostome of Iridmonoidea and Reticrescis, which are abundantly accompanied by the gadiform fish remains, penguin bones and whales. A sharp decrease in the bryozoan diversity near the contact between the Telm5 and Telm6 was connected with the climatic cooling event, which culminated at the time of deposition of the upper part of the LMF. The skeletal mineralogy along with the geochemical stable isotope studies of the bryozoans (Seymour Island, Antarctic Peninsula) help to elucidate the environmental and climatic changes connected with the Early Eocene Climatic Optimum (EECO), Middle Eocene Climatic Optimum (MECO) as well as the EOT in the stratigraphical profile of the La Meseta Formation. References Hara U. 2015. Bryozoan internal moulds from the La Meseta Formation (Eocene) of Seymour Island, Antarctic Peninsula. Polish Polar Research, vol. 36, 25-49. Hara U., Mors T., Hagstrom J. and Reguero M.A. 2017. Eocene bryozoans assemblages from the La Meseta Formation of Seymour Island, Antarctica (in review).

Vapor-dominated zones within hydrothermal systems: evolution and natural state

USGS Publications Warehouse

Ingebritsen, S.E.; Sorey, M.L.

1988-01-01

Three conceptual models illustrate the range of hydrothermal systems in which vapor-dominated conditions are found. The first model (model I) represents a system with an extensive near-vaporstatic vapor-dominated zone and limited liquid throughflow and is analogous to systems such as The Geysers, California. Models II and III represent systems with significant liquid throughflow and include steam-heated discharge features at higher elevations and high-chloride springs at lower elevations connected to and fed by a single circulation system at depth. In model II, as in model I, the vapor-dominated zone has a near-vaporstatic vertical pressure gradient and is generally underpressured with respect to local hydrostatic pressure. The vapor-dominated zone in model III is quite different, in that phase separation takes place at pressures close to local hydrostatic and the overall pressure gradient is near hydrostatic. -from Authors

Field Measurements of Respiratory Del13CO2 and Photodegradation

NASA Astrophysics Data System (ADS)

van Asperen, H.; Sabbatini, S.; Nicolini, G.; Warneke, T.; Papale, D.; Notholt, J.

2014-12-01

Carbon decomposition dynamics have been studied in a variety of ecosystems and its variation can mostly be explained in terms of environmental variables (e.g. temperature and precipitation). However, carbon dynamics in arid, water limited regions have shown to be very different and are still largely unknown. Several studies have indicated the importance of photodegradation, the direct breakdown of organic matter by sunlight, in these arid regions. A FTIR (Fourier Transform Infrared Spectrometer) was set up to continuously measure concentrations of CO2, CH4, N2O, CO as well as del13C in CO2. The FTIR was connected to 2 different flux measurement systems: a Flux Gradient system and 2 flux chambers, providing a continuous data set of gas concentrations and biosphere-atmosphere gas fluxes at different heights and scales. Field measurements showed photodegradation induced carbon fluxes. Also, respiratory del13CO2 was determined by use of Keeling plots, and was determined to vary between -25‰ and -21‰. A clear diurnal pattern in respiratory del13CO2 was found, suggesting either different (dominant) respiratory processes between day and night or the effect of diffusive fractionation.

Spatiotemporal Dependency of Age-Related Changes in Brain Signal Variability

PubMed Central

McIntosh, A. R.; Vakorin, V.; Kovacevic, N.; Wang, H.; Diaconescu, A.; Protzner, A. B.

2014-01-01

Recent theoretical and empirical work has focused on the variability of network dynamics in maturation. Such variability seems to reflect the spontaneous formation and dissolution of different functional networks. We sought to extend these observations into healthy aging. Two different data sets, one EEG (total n = 48, ages 18–72) and one magnetoencephalography (n = 31, ages 20–75) were analyzed for such spatiotemporal dependency using multiscale entropy (MSE) from regional brain sources. In both data sets, the changes in MSE were timescale dependent, with higher entropy at fine scales and lower at more coarse scales with greater age. The signals were parsed further into local entropy, related to information processed within a regional source, and distributed entropy (information shared between two sources, i.e., functional connectivity). Local entropy increased for most regions, whereas the dominant change in distributed entropy was age-related reductions across hemispheres. These data further the understanding of changes in brain signal variability across the lifespan, suggesting an inverted U-shaped curve, but with an important qualifier. Unlike earlier in maturation, where the changes are more widespread, changes in adulthood show strong spatiotemporal dependence. PMID:23395850

Dominance-based ranking functions for interval-valued intuitionistic fuzzy sets.

PubMed

Chen, Liang-Hsuan; Tu, Chien-Cheng

2014-08-01

The ranking of interval-valued intuitionistic fuzzy sets (IvIFSs) is difficult since they include the interval values of membership and nonmembership. This paper proposes ranking functions for IvIFSs based on the dominance concept. The proposed ranking functions consider the degree to which an IvIFS dominates and is not dominated by other IvIFSs. Based on the bivariate framework and the dominance concept, the functions incorporate not only the boundary values of membership and nonmembership, but also the relative relations among IvIFSs in comparisons. The dominance-based ranking functions include bipolar evaluations with a parameter that allows the decision-maker to reflect his actual attitude in allocating the various kinds of dominance. The relationship for two IvIFSs that satisfy the dual couple is defined based on four proposed ranking functions. Importantly, the proposed ranking functions can achieve a full ranking for all IvIFSs. Two examples are used to demonstrate the applicability and distinctiveness of the proposed ranking functions.

Steel Rack Connections: Identification of Most Influential Factors and a Comparison of Stiffness Design Methods.

PubMed

Shah, S N R; Sulong, N H Ramli; Shariati, Mahdi; Jumaat, M Z

2015-01-01

Steel pallet rack (SPR) beam-to-column connections (BCCs) are largely responsible to avoid the sway failure of frames in the down-aisle direction. The overall geometry of beam end connectors commercially used in SPR BCCs is different and does not allow a generalized analytic approach for all types of beam end connectors; however, identifying the effects of the configuration, profile and sizes of the connection components could be the suitable approach for the practical design engineers in order to predict the generalized behavior of any SPR BCC. This paper describes the experimental behavior of SPR BCCs tested using a double cantilever test set-up. Eight sets of specimens were identified based on the variation in column thickness, beam depth and number of tabs in the beam end connector in order to investigate the most influential factors affecting the connection performance. Four tests were repeatedly performed for each set to bring uniformity to the results taking the total number of tests to thirty-two. The moment-rotation (M-θ) behavior, load-strain relationship, major failure modes and the influence of selected parameters on connection performance were investigated. A comparative study to calculate the connection stiffness was carried out using the initial stiffness method, the slope to half-ultimate moment method and the equal area method. In order to find out the more appropriate method, the mean stiffness of all the tested connections and the variance in values of mean stiffness according to all three methods were calculated. The calculation of connection stiffness by means of the initial stiffness method is considered to overestimate the values when compared to the other two methods. The equal area method provided more consistent values of stiffness and lowest variance in the data set as compared to the other two methods.

Field measurements of del13C in ecosystem respiration

NASA Astrophysics Data System (ADS)

van Asperen, Hella; Sabbatini, Simone; Nicolini, Giacomo; Warneke, Thorsten; Papale, Dario; Notholt, Justus

2014-05-01

Stable carbon isotope del13C-measurements are extensively used to study ecological and biogeochemical processes in ecosystems. Above terrestrial ecosystems, atmospheric del13C can vary largely due to photosynthetic fractionation. Photosynthetic processes prefer the uptake of the lighter isotope 12C (in CO2), thereby enriching the atmosphere in 13C and depleting the ecosystem carbon. At night, when ecosystem respiratory fluxes are dominant, 13C-depleted CO2 is respired and thereby depletes the atmospheric del13C-content. Different ecosystems and different parts of one ecosystem (type of plant, leaves, and roots) fractionate and respire with a different del13C-ratio signature. By determining the del13C-signature of ecosystem respiration in temporal and spatial scale, an analysis can be made of the composition of respiratory sources of the ecosystem. A field study at a dry cropland after harvest (province of Viterbo, Lazio, Italy) was performed in the summer of 2013. A FTIR (Fourier Transform Infrared Spectrometer) was set up to continuously measure CO2-, CH4-, N2O-, CO- and del13C-concentrations. The FTIR was connected to 2 different flux measurements systems: a Flux Gradient system (sampling every half hour at 1.3m and 4.2m) and 2 flux chambers (measured every hour), providing a continuous data set of the biosphere-atmosphere gas fluxes and of the gas concentrations at different heights. Keeling plot intercept values of respiratory CO2, measured by the Flux Gradient system at night, were determined to be between -25‰ and -20‰. Keeling plot intercept values of respiratory CO2, measured by the flux chamber system, varied between -24‰ and -29‰, and showed a clear diurnal pattern, suggesting different (dominant) respiratory processes between day and night.

Teacher learning from girls' informal science experiences

NASA Astrophysics Data System (ADS)

Birmingham, Daniel J.

School science continues to fail to engage youth from non-dominant communities (Carlone, Huan-Frank & Webb, 2011). However, recent research demonstrates that informal science learning settings support both knowledge gains and increased participation in science among youth from non-dominant communities (Dierking, 2007; Falk et al., 2007; HFRP, 2010). Despite the success, little is known about how teachers can learn from informal science practices to support student engagement in science. In this study, I examine the impact informal science experiences has for the teaching and learning of science in school contexts. This study is focused on eliciting girls' stories of informal science learning experiences and sharing these stories with science teachers to examine what they notice and make meaning of in connection with their classroom practices (van Es & Sherin, 2002). I co-constructed cases of informal science experiences with middle school females who participate in an after school science program in an urban area. These cases consisted of the girls' written stories, their explicit messages to science teachers, examples of actions taken when investigating community based science issues and transcripts of conversations between the girls and researchers. These cases were shared with local science teachers in order to investigate what they "notice" (van Es & Sherin, 2002) regarding girls' participation in informal science learning, how they make meaning of youths' stories and whether the stories influence their classroom practices. I found that the girls' use their cases to share experiences of how, where and why science matters, to express hope for school science and to critique stereotypical views that young, female, students of color from lower SES backgrounds are not interested or capable of making contributions to scientific investigations. Additionally, I found that teachers noticed powerful messages within and across the girls' cases. The messages include; 1) students' desire to be active participants in science investigations, 2) the need to provide spaces for students to leverage their strengths when learning and doing science, 3) the importance of building connections between science and community, and 4) expanding the outcomes of scientific investigations beyond traditional school measures. However, their individual meaning making was influenced by tensions between what they found powerful in the cases, the institutional narratives that often guide practice in schools and the societal and personal narratives connected to participation of girls from non dominant communities in science. Thus, each of the three teachers took different pathways as they implemented new science learning experiences based upon what each found most salient in the girls' stories as well as the influence of institutional, societal and personal narratives, resulting in varied learning experiences for their students.

Organizing principles for the cerebral cortex network of commissural and association connections

PubMed Central

Swanson, Larry W.; Hahn, Joel D.; Sporns, Olaf

2017-01-01

Cognition is supported by a network of axonal connections between gray matter regions within and between right and left cerebral cortex. Global organizing principles of this circuitry were examined with network analysis tools applied to monosynaptic association (within one side) and commissural (between sides) connections between all 77 cortical gray matter regions in each hemisphere of the rat brain. The analysis used 32,350 connection reports expertly collated from published pathway tracing experiments, and 5,394 connections of a possible 23,562 were identified, for a connection density of 23%—of which 20% (1,084) were commissural. Network community detection yielded a stable bihemispheric six-module solution, with an identical set in each hemisphere of three modules topographically forming a lateral core and medial shell arrangement of cortical regions. Functional correlations suggest the lateral module deals preferentially with environmental sensory-motor interactions and the ventromedial module deals preferentially with visceral control, affect, and short-term memory, whereas the dorsomedial module resembles the default mode network. Analysis of commissural connections revealed a set of unexpected rules to help generate hypotheses. Most notably, there is an order of magnitude more heterotopic than homotopic projections; all cortical regions send more association than commissural connections, and for each region, the latter are always a subset of the former; the number of association connections from each cortical region strongly correlates with the number of its commissural connections; and the module (dorsomedial) lying closest to the corpus callosum has the most complete set of commissural connections—and apparently the most complex function. PMID:29078382

Individual differences in the dominance of interhemispheric connections predict cognitive ability beyond sex and brain size.

PubMed

Martínez, Kenia; Janssen, Joost; Pineda-Pardo, José Ángel; Carmona, Susanna; Román, Francisco Javier; Alemán-Gómez, Yasser; Garcia-Garcia, David; Escorial, Sergio; Quiroga, María Ángeles; Santarnecchi, Emiliano; Navas-Sánchez, Francisco Javier; Desco, Manuel; Arango, Celso; Colom, Roberto

2017-07-15

Global structural brain connectivity has been reported to be sex-dependent with women having increased interhemispheric connectivity (InterHc) and men having greater intrahemispheric connectivity (IntraHc). However, (a) smaller brains show greater InterHc, (b) larger brains show greater IntraHc, and (c) women have, on average, smaller brains than men. Therefore, sex differences in brain size may modulate sex differences in global brain connectivity. At the behavioural level, sex-dependent differences in connectivity are thought to contribute to men-women differences in spatial and verbal abilities. But this has never been tested at the individual level. The current study assessed whether individual differences in global structural connectome measures (InterHc, IntraHc and the ratio of InterHc relative to IntraHc) predict spatial and verbal ability while accounting for the effect of sex and brain size. The sample included forty men and forty women, who did neither differ in age nor in verbal and spatial latent components defined by a broad battery of tests and tasks. High-resolution T 1 -weighted and diffusion-weighted images were obtained for computing brain size and reconstructing the structural connectome. Results showed that men had higher IntraHc than women, while women had an increased ratio InterHc/IntraHc. However, these sex differences were modulated by brain size. Increased InterHc relative to IntraHc predicted higher spatial and verbal ability irrespective of sex and brain size. The positive correlations between the ratio InterHc/IntraHc and the spatial and verbal abilities were confirmed in 1000 random samples generated by bootstrapping. Therefore, sex differences in global structural connectome connectivity were modulated by brain size and did not underlie sex differences in verbal and spatial abilities. Rather, the level of dominance of InterHc over IntraHc may be associated with individual differences in verbal and spatial abilities in both men and women. Copyright © 2017 Elsevier Inc. All rights reserved.

Neural field theory of perceptual echo and implications for estimating brain connectivity

NASA Astrophysics Data System (ADS)

Robinson, P. A.; Pagès, J. C.; Gabay, N. C.; Babaie, T.; Mukta, K. N.

2018-04-01

Neural field theory is used to predict and analyze the phenomenon of perceptual echo in which random input stimuli at one location are correlated with electroencephalographic responses at other locations. It is shown that this echo correlation (EC) yields an estimate of the transfer function from the stimulated point to other locations. Modal analysis then explains the observed spatiotemporal structure of visually driven EC and the dominance of the alpha frequency; two eigenmodes of similar amplitude dominate the response, leading to temporal beating and a line of low correlation that runs from the crown of the head toward the ears. These effects result from mode splitting and symmetry breaking caused by interhemispheric coupling and cortical folding. It is shown how eigenmodes obtained from functional magnetic resonance imaging experiments can be combined with temporal dynamics from EC or other evoked responses to estimate the spatiotemporal transfer function between any two points and hence their effective connectivity.

Can Retinal Ganglion Cell Dipoles Seed Iso-Orientation Domains in the Visual Cortex?

PubMed Central

Schottdorf, Manuel; Eglen, Stephen J.; Wolf, Fred; Keil, Wolfgang

2014-01-01

It has been argued that the emergence of roughly periodic orientation preference maps (OPMs) in the primary visual cortex (V1) of carnivores and primates can be explained by a so-called statistical connectivity model. This model assumes that input to V1 neurons is dominated by feed-forward projections originating from a small set of retinal ganglion cells (RGCs). The typical spacing between adjacent cortical orientation columns preferring the same orientation then arises via Moiré-Interference between hexagonal ON/OFF RGC mosaics. While this Moiré-Interference critically depends on long-range hexagonal order within the RGC mosaics, a recent statistical analysis of RGC receptive field positions found no evidence for such long-range positional order. Hexagonal order may be only one of several ways to obtain spatially repetitive OPMs in the statistical connectivity model. Here, we investigate a more general requirement on the spatial structure of RGC mosaics that can seed the emergence of spatially repetitive cortical OPMs, namely that angular correlations between so-called RGC dipoles exhibit a spatial structure similar to that of OPM autocorrelation functions. Both in cat beta cell mosaics as well as primate parasol receptive field mosaics we find that RGC dipole angles are spatially uncorrelated. To help assess the level of these correlations, we introduce a novel point process that generates mosaics with realistic nearest neighbor statistics and a tunable degree of spatial correlations of dipole angles. Using this process, we show that given the size of available data sets, the presence of even weak angular correlations in the data is very unlikely. We conclude that the layout of ON/OFF ganglion cell mosaics lacks the spatial structure necessary to seed iso-orientation domains in the primary visual cortex. PMID:24475081

Can retinal ganglion cell dipoles seed iso-orientation domains in the visual cortex?

PubMed

Schottdorf, Manuel; Eglen, Stephen J; Wolf, Fred; Keil, Wolfgang

2014-01-01

It has been argued that the emergence of roughly periodic orientation preference maps (OPMs) in the primary visual cortex (V1) of carnivores and primates can be explained by a so-called statistical connectivity model. This model assumes that input to V1 neurons is dominated by feed-forward projections originating from a small set of retinal ganglion cells (RGCs). The typical spacing between adjacent cortical orientation columns preferring the same orientation then arises via Moiré-Interference between hexagonal ON/OFF RGC mosaics. While this Moiré-Interference critically depends on long-range hexagonal order within the RGC mosaics, a recent statistical analysis of RGC receptive field positions found no evidence for such long-range positional order. Hexagonal order may be only one of several ways to obtain spatially repetitive OPMs in the statistical connectivity model. Here, we investigate a more general requirement on the spatial structure of RGC mosaics that can seed the emergence of spatially repetitive cortical OPMs, namely that angular correlations between so-called RGC dipoles exhibit a spatial structure similar to that of OPM autocorrelation functions. Both in cat beta cell mosaics as well as primate parasol receptive field mosaics we find that RGC dipole angles are spatially uncorrelated. To help assess the level of these correlations, we introduce a novel point process that generates mosaics with realistic nearest neighbor statistics and a tunable degree of spatial correlations of dipole angles. Using this process, we show that given the size of available data sets, the presence of even weak angular correlations in the data is very unlikely. We conclude that the layout of ON/OFF ganglion cell mosaics lacks the spatial structure necessary to seed iso-orientation domains in the primary visual cortex.

Whitby Mudstone, flow from matrix to fractures

NASA Astrophysics Data System (ADS)

Houben, Maartje; Hardebol, Nico; Barnhoorn, Auke; Boersma, Quinten; Peach, Colin; Bertotti, Giovanni; Drury, Martyn

2016-04-01

Fluid flow from matrix to well in shales would be faster if we account for the duality of the permeable medium considering a high permeable fracture network together with a tight matrix. To investigate how long and how far a gas molecule would have to travel through the matrix until it reaches an open connected fracture we investigated the permeability of the Whitby Mudstone (UK) matrix in combination with mapping the fracture network present in the current outcrops of the Whitby Mudstone at the Yorkshire coast. Matrix permeability was measured perpendicular to the bedding using a pressure step decay method on core samples and permeability values are in the microdarcy range. The natural fracture network present in the pavement shows a connected network with dominant NS and EW strikes, where the NS fractures are the main fracture set with an orthogonal fracture set EW. Fracture spacing relations in the pavements show that the average distance to the nearest fracture varies between 7 cm (EW) and 14 cm (NS), where 90% of the matrix is 30 cm away from the nearest fracture. By making some assumptions like; fracture network at depth is similar to what is exposed in the current pavements and open to flow, fracture network is at hydrostatic pressure at 3 km depth, overpressure between matrix and fractures is 10% and a matrix permeability perpendicular to the bedding of 0.1 microdarcy, we have calculated the time it takes for a gas molecule to travel to the nearest fracture. These input values give travel times up to 8 days for a distance of 14 cm. If the permeability is changed to 1 nanodarcy or 10 microdarcy travel times change to 2.2 years or 2 hours respectively.

Assemblage patterns of fish functional groups relative to habitat connectivity and conditions in floodplain lakes

USGS Publications Warehouse

Miyazono, S.; Aycock, J.N.; Miranda, L.E.; Tietjen, T.E.

2010-01-01

We evaluated the influences of habitat connectivity and local environmental factors on the distribution and abundance patterns of fish functional groups in 17 floodplain lakes in the Yazoo River Basin, USA. The results of univariate and multivariate analyses showed that species-environmental relationships varied with the functional groups. Species richness and assemblage structure of periodic strategists showed strong and positive correlations with habitat connectivity. Densities of most equilibrium and opportunistic strategists decreased with habitat connectivity. Densities of certain equilibrium and opportunistic strategists increased with turbidity. Forested wetlands around the lakes were positively related to the densities of periodic and equilibrium strategists. These results suggest that decreases in habitat connectivity, forested wetland buffers and water quality resulting from environmental manipulations may cause local extinction of certain fish taxa and accelerate the dominance of tolerant fishes in floodplain lakes. ?? 2010 John Wiley & Sons A/S.

The timeless caring connection.

PubMed

Schwerin, Judi I

2004-01-01

Caring is the essence of nursing. However, one cannot assume that caring is enough, especially if the recipient has not perceived the message of caring. The nursing connection is defined as the successful communication of caring by a nurse, whereby the recipient of care can trust the message of caring and respond to the message in its entirety. The caring connection has special significance today because of the changing societal trends, the domination of chronic illness as the major player in the population's morbidity and mortality, and the need for the public to practice prevention and/or management of chronic disease through lifestyle changes. The challenge for nursing is presented in the role of the nurse as a coach. Key strategies for establishing a caring connection in the nurse-client relationship are identified. An authentic caring connection is an empowering dialogue and exchange of the human spirit-nothing but the sacred ground in nursing practice.

Electrical interconnect

DOEpatents

Frost, John S.; Brandt, Randolph J.; Hebert, Peter; Al Taher, Omar

2015-10-06

An interconnect includes a first set of connector pads, a second set of connector pads, and a continuous central portion. A first plurality of legs extends at a first angle from the continuous central portion. Each leg of the first plurality of legs is connected to a connector pad of a first set of connector pads. A second plurality of legs extends at a second angle from the continuous central portion. Each leg of the second plurality of legs is connected to a connector pad of the second set of connector pads. Gaps are defined between legs. The gaps enable movement of the first set of connector pads relative to the second set of connector pads.

Oceanography and life history predict contrasting genetic population structure in two Antarctic fish species.

PubMed

Young, Emma F; Belchier, Mark; Hauser, Lorenz; Horsburgh, Gavin J; Meredith, Michael P; Murphy, Eugene J; Pascoal, Sonia; Rock, Jennifer; Tysklind, Niklas; Carvalho, Gary R

2015-06-01

Understanding the key drivers of population connectivity in the marine environment is essential for the effective management of natural resources. Although several different approaches to evaluating connectivity have been used, they are rarely integrated quantitatively. Here, we use a 'seascape genetics' approach, by combining oceanographic modelling and microsatellite analyses, to understand the dominant influences on the population genetic structure of two Antarctic fishes with contrasting life histories, Champsocephalus gunnari and Notothenia rossii. The close accord between the model projections and empirical genetic structure demonstrated that passive dispersal during the planktonic early life stages is the dominant influence on patterns and extent of genetic structuring in both species. The shorter planktonic phase of C. gunnari restricts direct transport of larvae between distant populations, leading to stronger regional differentiation. By contrast, geographic distance did not affect differentiation in N. rossii, whose longer larval period promotes long-distance dispersal. Interannual variability in oceanographic flows strongly influenced the projected genetic structure, suggesting that shifts in circulation patterns due to climate change are likely to impact future genetic connectivity and opportunities for local adaptation, resilience and recovery from perturbations. Further development of realistic climate models is required to fully assess such potential impacts.

Lake Superior Coastal Wetland Fish Assemblages and ...

EPA Pesticide Factsheets

The role of the coastal margin and the watershed context in defining the ecology of even very large lakes is increasingly being recognized and examined. Coastal wetlands are both important contributors to the biodiversity and productivity of large lakes and important mediators of the lake-basin connection. We explored wetland-watershed connections and their relationship to wetland function and condition using data collected from 37 Lake Superior wetlands spanning a substantial geographic and geomorphic gradient. While none of these wetlands are particularly disturbed, there were nevertheless clear relationships between watershed landuse and wetland habitat and biota, and these varied consistently across wetland type categories that reflected the strength of connection to the watershed. For example, water clarity and vegetation structure complexity declined with decreasing percent natural land cover, and these effects were strongest in riverine wetlands (having generally large watersheds and tributary-dominated hydrology) and weakest in lagoon wetlands (having generally small watersheds and lake-dominate hydrology). Fish abundance and species richness both increased with decreasing percent natural land cover while species diversity decreased, and again the effect was strongest in riverine wetlands. Lagoonal wetlands, which lack any substantial tributary, consistently harbored the fewest species of fish and a composition different from the more watershed-lin

Transcriptome analysis of skin fibroblasts with dominant negative COL3A1 mutations provides molecular insights into the etiopathology of vascular Ehlers-Danlos syndrome

PubMed Central

Chiarelli, Nicola; Carini, Giulia; Zoppi, Nicoletta; Ritelli, Marco

2018-01-01

Vascular Ehlers-Danlos syndrome (vEDS) is a dominantly inherited connective tissue disorder caused by mutations in the COL3A1 gene that encodes type III collagen (COLLIII), which is the major expressed collagen in blood vessels and hollow organs. The majority of disease-causing variants in COL3A1 are glycine substitutions and in-frame splice mutations in the triple helix domain that through a dominant negative effect are associated with the severe clinical spectrum potentially lethal of vEDS, characterized by fragility of soft connective tissues with arterial and organ ruptures. To shed lights into molecular mechanisms underlying vEDS, we performed gene expression profiling in cultured skin fibroblasts from three patients with different structural COL3A1 mutations. Transcriptome analysis revealed significant changes in the expression levels of several genes involved in maintenance of cell redox and endoplasmic reticulum (ER) homeostasis, COLLs folding and extracellular matrix (ECM) organization, formation of the proteasome complex, and cell cycle regulation. Protein analyses showed that aberrant COLLIII expression is associated with the disassembly of many structural ECM constituents, such as fibrillins, EMILINs, and elastin, as well as with the reduction of the proteoglycans perlecan, decorin, and versican, all playing an important role in the vascular system. Furthermore, the altered distribution of the ER marker protein disulfide isomerase PDI and the strong reduction of the COLLs-modifying enzyme FKBP22 are consistent with the disturbance of ER-related homeostasis and COLLs biosynthesis and post-translational modifications, indicated by microarray analysis. Our findings add new insights into the pathophysiology of this severe vascular disorder, since they provide a picture of the gene expression changes in vEDS skin fibroblasts and highlight that dominant negative mutations in COL3A1 also affect post-translational modifications and deposition into the ECM of several structural proteins crucial to the integrity of soft connective tissues. PMID:29346445

Transcriptome analysis of skin fibroblasts with dominant negative COL3A1 mutations provides molecular insights into the etiopathology of vascular Ehlers-Danlos syndrome.

PubMed

Chiarelli, Nicola; Carini, Giulia; Zoppi, Nicoletta; Ritelli, Marco; Colombi, Marina

2018-01-01

Vascular Ehlers-Danlos syndrome (vEDS) is a dominantly inherited connective tissue disorder caused by mutations in the COL3A1 gene that encodes type III collagen (COLLIII), which is the major expressed collagen in blood vessels and hollow organs. The majority of disease-causing variants in COL3A1 are glycine substitutions and in-frame splice mutations in the triple helix domain that through a dominant negative effect are associated with the severe clinical spectrum potentially lethal of vEDS, characterized by fragility of soft connective tissues with arterial and organ ruptures. To shed lights into molecular mechanisms underlying vEDS, we performed gene expression profiling in cultured skin fibroblasts from three patients with different structural COL3A1 mutations. Transcriptome analysis revealed significant changes in the expression levels of several genes involved in maintenance of cell redox and endoplasmic reticulum (ER) homeostasis, COLLs folding and extracellular matrix (ECM) organization, formation of the proteasome complex, and cell cycle regulation. Protein analyses showed that aberrant COLLIII expression is associated with the disassembly of many structural ECM constituents, such as fibrillins, EMILINs, and elastin, as well as with the reduction of the proteoglycans perlecan, decorin, and versican, all playing an important role in the vascular system. Furthermore, the altered distribution of the ER marker protein disulfide isomerase PDI and the strong reduction of the COLLs-modifying enzyme FKBP22 are consistent with the disturbance of ER-related homeostasis and COLLs biosynthesis and post-translational modifications, indicated by microarray analysis. Our findings add new insights into the pathophysiology of this severe vascular disorder, since they provide a picture of the gene expression changes in vEDS skin fibroblasts and highlight that dominant negative mutations in COL3A1 also affect post-translational modifications and deposition into the ECM of several structural proteins crucial to the integrity of soft connective tissues.

Role of brain hemispheric dominance in anticipatory postural control strategies.

PubMed

Cioncoloni, David; Rosignoli, Deborah; Feurra, Matteo; Rossi, Simone; Bonifazi, Marco; Rossi, Alessandro; Mazzocchio, Riccardo

2016-07-01

Most of the cerebral functions are asymmetrically represented in the two hemispheres. Moreover, dexterity and coordination of the distal segment of the dominant limbs depend on cortico-motor lateralization. In this study, we investigated whether postural control may be also considered a lateralized hemispheric brain function. To this aim, 15 young subjects were tested in standing position by measuring center of pressure (COP) shifts along the anteroposterior axis (COP-Y) during dynamic posturography before and after continuous Theta Burst Stimulation (cTBS) intervention applied to the dominant or non-dominant M1 hand area as well as to the vertex. We show that when subjects were expecting a forward platform translation, the COP-Y was positioned significantly backward or forward after dominant or non-dominant M1 stimulation, respectively. We postulate that cTBS applied on M1 may have disrupted the functional connectivity between intra- and interhemispheric areas implicated in the anticipatory control of postural stability. This study suggests a functional asymmetry between the two homologous primary motor areas, with the dominant hemisphere playing a critical role in the selection of the appropriate postural control strategy.

Analysis of the thermal balance characteristics for multiple-connected piezoelectric transformers.

PubMed

Park, Joung-Hu; Cho, Bo-Hyung; Choi, Sung-Jin; Lee, Sang-Min

2009-08-01

Because the amount of power that a piezoelectric transformer (PT) can handle is limited, multiple connections of PTs are necessary for the power-capacity improvement of PT-applications. In the connection, thermal imbalance between the PTs should be prevented to avoid the thermal runaway of each PT. The thermal balance of the multiple-connected PTs is dominantly affected by the electrothermal characteristics of individual PTs. In this paper, the thermal balance of both parallel-parallel and parallel-series connections are analyzed by electrical model parameters. For quantitative analysis, the thermal-balance effects are estimated by the simulation of the mechanical loss ratio between the PTs. The analysis results show that with PTs of similar characteristics, the parallel-series connection has better thermal balance characteristics due to the reduced mechanical loss of the higher temperature PT. For experimental verification of the analysis, a hardware-prototype test of a Cs-Lp type 40 W adapter system with radial-vibration mode PTs has been performed.

Interference-Free and Interference-Dominated Photoionization: Synthesis of Ultrashort and Coherent Single-Electron Wave Packets

NASA Astrophysics Data System (ADS)

Cajiao Vélez, F.; Kamiński, J. Z.; Krajewska, K.

2018-04-01

Ionization of hydrogen-like ions driven by intense, short, and circularly-polarized laser pulses is considered under the scope of the relativistic strong-field approximation. We show that the energy spectra of photoelectrons can exhibit two types of structures, i.e., interference-dominated or interference-free ones. These structures are analyzed in connection to the time-dependent ponderomotive energy of electrons in the laser field. A possibility of synthesis of ultrashort single-electron pulses from those structures is also investigated.

Radiation-hardened transistor and integrated circuit

DOEpatents

Ma, Kwok K.

2007-11-20

A composite transistor is disclosed for use in radiation hardening a CMOS IC formed on an SOI or bulk semiconductor substrate. The composite transistor has a circuit transistor and a blocking transistor connected in series with a common gate connection. A body terminal of the blocking transistor is connected only to a source terminal thereof, and to no other connection point. The blocking transistor acts to prevent a single-event transient (SET) occurring in the circuit transistor from being coupled outside the composite transistor. Similarly, when a SET occurs in the blocking transistor, the circuit transistor prevents the SET from being coupled outside the composite transistor. N-type and P-type composite transistors can be used for each and every transistor in the CMOS IC to radiation harden the IC, and can be used to form inverters and transmission gates which are the building blocks of CMOS ICs.

Hydrogeological controls on post-fire moss recovery in peatlands

NASA Astrophysics Data System (ADS)

Lukenbach, M. C.; Devito, K. J.; Kettridge, N.; Petrone, R. M.; Waddington, J. M.

2015-11-01

Wildfire is the largest disturbance affecting boreal peatlands, however, little is known about the controls on post-fire peatland vegetation recovery. While small-scale variation in burn severity can reduce post-fire moss water availability, high water table (WT) positions following wildfire are also critical to enable the re-establishment of keystone peatland mosses (i.e. Sphagnum). Thus, post-fire moss water availability is also likely a function of landscape-scale controls on peatland WT dynamics, specifically, connectivity to groundwater flow systems (i.e. hydrogeological setting). For this reason, we assessed the interacting controls of hydrogeological setting and burn severity on post-fire moss water availability in three burned, Sphagnum-dominated peatlands in Alberta's Boreal Plains. At all sites, variation in burn severity resulted in a dichotomy between post-fire surface covers that: (1) exhibited low water availability, regardless of WT position, and had minimal (<5%) moss re-establishment (i.e. lightly burned feather mosses and severely burned Sphagnum fuscum) or (2) exhibited high water availability, depending on WT position, and had substantial (>50%) moss re-establishment (i.e. lightly burned S. fuscum and where depth of burn was >0.05 m). Notably, hydrogeological setting influenced the spatial coverage of these post-fire surface covers by influencing pre-fire WTs and stand characteristics (e.g., shading). Because feather moss cover is controlled by tree shading, lightly burned feather mosses were ubiquitous (>25%) in drier peatlands (deeper pre-fire WTs) that were densely treed and had little connection to large groundwater flow systems. Moreover, hydrogeological setting also controlled post-fire WT positions, thereby affecting moss re-establishment in post-fire surface covers that were dependent on WT position (e.g., lightly burned S. fuscum). Accordingly, higher recolonization rates were observed in a peatland located in a groundwater flow through system that had a shallow post-fire WT. Therefore, we argue that hydrogeological setting influences post-fire recovery in two ways: (1) by influencing vegetation structure prior to wildfire, thereby controlling the coverage of post-fire surface covers and (2) by influencing post-fire WT positions. These results suggest that post-fire moss recovery in peatlands isolated from groundwater flow systems may be particularly susceptible to droughts and future climate change.

36 CFR 262.1 - Rewards in connection with fire or property prosecutions.

Code of Federal Regulations, 2011 CFR

2011-07-01

... fire or property prosecutions. 262.1 Section 262.1 Parks, Forests, and Public Property FOREST SERVICE... connection with fire or property prosecutions. (a) Hereafter, provided Congress shall make the necessary... of willfully or maliciously setting on fire, or causing to be set on fire, any timber, underbrush, or...

36 CFR 262.1 - Rewards in connection with fire or property prosecutions.

Code of Federal Regulations, 2012 CFR

2012-07-01

... fire or property prosecutions. 262.1 Section 262.1 Parks, Forests, and Public Property FOREST SERVICE... connection with fire or property prosecutions. (a) Hereafter, provided Congress shall make the necessary... of willfully or maliciously setting on fire, or causing to be set on fire, any timber, underbrush, or...

36 CFR 262.1 - Rewards in connection with fire or property prosecutions.

Code of Federal Regulations, 2014 CFR

2014-07-01

... fire or property prosecutions. 262.1 Section 262.1 Parks, Forests, and Public Property FOREST SERVICE... connection with fire or property prosecutions. (a) Hereafter, provided Congress shall make the necessary... of willfully or maliciously setting on fire, or causing to be set on fire, any timber, underbrush, or...

36 CFR 262.1 - Rewards in connection with fire or property prosecutions.

Code of Federal Regulations, 2013 CFR

2013-07-01

... fire or property prosecutions. 262.1 Section 262.1 Parks, Forests, and Public Property FOREST SERVICE... connection with fire or property prosecutions. (a) Hereafter, provided Congress shall make the necessary... of willfully or maliciously setting on fire, or causing to be set on fire, any timber, underbrush, or...

FOCCoS for Subaru PFS

NASA Astrophysics Data System (ADS)

Cesar de Oliveira, Antonio; Souza de Oliveira, Ligia; de Arruda, Marcio V.; Bispo dos Santos, Jesulino; Souza Marrara, Lucas; Bawden de Paula Macanhan, Vanessa; Batista de Carvalho Oliveira, João.; de Paiva Vilaça, Rodrigo; Dominici, Tania P.; Sodré, Laerte; Mendes de Oliveira, Claudia; Karoji, Hiroshi; Sugai, Hajime; Shimono, Atsushi; Tamura, Naoyuki; Takato, Naruhisa; Ueda, Akitoshi

2012-09-01

The Fiber Optical Cable and Connector System (FOCCoS), provides optical connection between 2400 positioners and a set of spectrographs by an optical fibers cable as part of Subaru PFS instrument. Each positioner retains one fiber entrance attached at a microlens, which is responsible for the F-ratio transformation into a larger one so that difficulties of spectrograph design are eased. The optical fibers cable will be segmented in 3 parts at long of the way, cable A, cable B and cable C, connected by a set of multi-fibers connectors. Cable B will be permanently attached at the Subaru telescope. The first set of multi-fibers connectors will connect the cable A to the cable C from the spectrograph system at the Nasmith platform. The cable A, is an extension of a pseudo-slit device obtained with the linear disposition of the extremities of the optical fibers and fixed by epoxy at a base of composite substrate. The second set of multi-fibers connectors will connect the other extremity of cable A to the cable B, which is part of the positioner's device structure. The optical fiber under study for this project is the Polymicro FBP120170190, which has shown very encouraging results. The kind of test involves FRD measurements caused by stress induced by rotation and twist of the fiber extremity, similar conditions to those produced by positioners of the PFS instrument. The multi-fibers connector under study is produced by USCONEC Company and may connect 32 optical fibers. The tests involve throughput of light and stability after many connections and disconnections. This paper will review the general design of the FOCCoS subsystem, methods used to fabricate the devices involved and the tests results necessary to evaluate the total efficiency of the set.

Approximating natural connectivity of scale-free networks based on largest eigenvalue

NASA Astrophysics Data System (ADS)

Tan, S.-Y.; Wu, J.; Li, M.-J.; Lu, X.

2016-06-01

It has been recently proposed that natural connectivity can be used to efficiently characterize the robustness of complex networks. The natural connectivity has an intuitive physical meaning and a simple mathematical formulation, which corresponds to an average eigenvalue calculated from the graph spectrum. However, as a network model close to the real-world system that widely exists, the scale-free network is found difficult to obtain its spectrum analytically. In this article, we investigate the approximation of natural connectivity based on the largest eigenvalue in both random and correlated scale-free networks. It is demonstrated that the natural connectivity of scale-free networks can be dominated by the largest eigenvalue, which can be expressed asymptotically and analytically to approximate natural connectivity with small errors. Then we show that the natural connectivity of random scale-free networks increases linearly with the average degree given the scaling exponent and decreases monotonically with the scaling exponent given the average degree. Moreover, it is found that, given the degree distribution, the more assortative a scale-free network is, the more robust it is. Experiments in real networks validate our methods and results.

Understanding spatial connectivity of individuals with non-uniform population density.

PubMed

Wang, Pu; González, Marta C

2009-08-28

We construct a two-dimensional geometric graph connecting individuals placed in space within a given contact distance. The individuals are distributed using a measured country's density of population. We observe that while large clusters (group of individuals connected) emerge within some regions, they are trapped in detached urban areas owing to the low population density of the regions bordering them. To understand the emergence of a giant cluster that connects the entire population, we compare the empirical geometric graph with the one generated by placing the same number of individuals randomly in space. We find that, for small contact distances, the empirical distribution of population dominates the growth of connected components, but no critical percolation transition is observed in contrast to the graph generated by a random distribution of population. Our results show that contact distances from real-world situations as for WIFI and Bluetooth connections drop in a zone where a fully connected cluster is not observed, hinting that human mobility must play a crucial role in contact-based diseases and wireless viruses' large-scale spreading.

Brain connectivity associated with cascading levels of language.

PubMed

Richards, Todd; Nagy, William; Abbott, Robert; Berninger, Virginia

2016-01-01

Typical oral and written language learners (controls) (5 girls, 4 boys) completed fMRI reading judgment tasks (sub-word grapheme-phoneme, word spelling, sentences with and without spelling foils, affixed words, sentences with and without affix foils, and multi-sentence). Analyses identified connectivity within and across adjacent levels (units) of language in reading: from subword to word to syntax in Set I and from word to syntax to multi-sentence in Set II). Typicals were compared to (a) students with dyslexia (6 girls, 10 boys) on the subword and word tasks in Set I related to levels of language impaired in dyslexia, and (b) students with oral and written language learning disability (OWL LD) (3 girls, 2 boys) on the morphology and syntax tasks in Set II, related to levels of language impaired in OWL LD. Results for typical language learners showed that adjacent levels of language in the reading brain share common and unique connectivity. The dyslexia group showed over-connectivity to a greater degree on the imaging tasks related to their levels of language impairments than the OWL LD group who showed under-connectivity to a greater degree than did the dyslexia group on the imaging tasks related to their levels of language impairment. Results for these students in grades 4 to 9 (ages 9 to 14) are discussed in reference to the contribution of patterns of connectivity across levels of language to understanding the nature of persisting dyslexia and dysgraphia despite early intervention.

Microbial Ecology of a Regional Flow System: Deep, Aerobic, Fractured Rock Aquifers of the US Basin and Range (Invited)

NASA Astrophysics Data System (ADS)

Moser, D. P.; Hamilton-Brehm, S.; Zhang, G.; Fisher, J.; Hughes, K.; Wheatley, A.; Thomas, J.; Zavarin, M.; Roberts, S. K.; Kryder, L.; McRae, R.; Howard, W.; Walker, J.; Federwisch, R.; King, M.; Friese, R.; Grim, S.; Amend, J.; Momper, L.; Sherwood Lollar, B.; Onstott, T. C.

2013-12-01

Recent decades have revealed anaerobic microbial ecosystems across a range of deep, continental settings; however, aerobic, regional aquifers represent a little-studied habitat for deep life. The US' Basin and Range Province is an extensional zone defined by deep, interconnected fracture systems that span multiple hydrologic basins and host regional aquifers. Here we describe a multi-basin microbiological assessment, applied to the Death Valley Regional Flow System (DVRFS). Our group has surveyed more than thirty deep boreholes (~ 1,000 m depth average) and deeply-sourced springs across a ~170 km inferred flow path from recharge areas in volcanic and carbonate rock highlands of the Nevada National Security Site (NNSS) and the Spring Mountains to discharge zones in Oasis, Amargosa, and Death Valleys. DVRFS waters were characterized by temperatures of 30 - 50 oC and the presence of dissolved O2 (4 - 8 mg/L in the recharge areas and ~0.2 - 2 mg/L in the discharge zones). Planktonic microbial populations, as tracked by molecular DNA approaches (e.g. 454 pyrotag), were of low abundance (e.g. ~ 10e3 ~10e6 per mL) and dominated by Proteobacteria and Nitrospirae. Archaea were also present and dominated by novel Thaumarchaeotes. Patterns of microbial diversity and the hypothesis that these patterns may have utility for recognition of hydrologic connectivity were assessed by statistical tools. At the species level, cosmopolitan, system-wide, and flow-path-specific groupings of both bacteria and archaea were detected. Even when in close proximity to aerobic springs and wells, sites sampling deep, hot, anaerobic groundwaters possessed completely distinct microbial populations (e.g. dominance by Firmicutes, ANME, and predicted methanogens). Among methodological refinements developed from this work, the repeated sampling of one deep borehole over a month-long pump test revealed that well-bore-associated contaminants required several days of pumping for complete removal and enabled the identification of the specific depth that produced most of the water. Our results reveal details of microbial community structure for a common, but little-studied microbial ecosystem and support the concept that regional flow systems possess distinct microbial populations, consistent with their geochemical and hydrologic characteristics. These results generally support the concept that microbial populations may have utility as amplifiable tracers for tracking the connectivity of fluids in the subsurface.

Sensitivity of marine protected area network connectivity to atmospheric variability

NASA Astrophysics Data System (ADS)

Fox, Alan D.; Henry, Lea-Anne; Corne, David W.; Roberts, J. Murray

2016-11-01

International efforts are underway to establish well-connected systems of marine protected areas (MPAs) covering at least 10% of the ocean by 2020. But the nature and dynamics of ocean ecosystem connectivity are poorly understood, with unresolved effects of climate variability. We used 40-year runs of a particle tracking model to examine the sensitivity of an MPA network for habitat-forming cold-water corals in the northeast Atlantic to changes in larval dispersal driven by atmospheric cycles and larval behaviour. Trajectories of Lophelia pertusa larvae were strongly correlated to the North Atlantic Oscillation (NAO), the dominant pattern of interannual atmospheric circulation variability over the northeast Atlantic. Variability in trajectories significantly altered network connectivity and source-sink dynamics, with positive phase NAO conditions producing a well-connected but asymmetrical network connected from west to east. Negative phase NAO produced reduced connectivity, but notably some larvae tracked westward-flowing currents towards coral populations on the mid-Atlantic ridge. Graph theoretical metrics demonstrate critical roles played by seamounts and offshore banks in larval supply and maintaining connectivity across the network. Larval longevity and behaviour mediated dispersal and connectivity, with shorter lived and passive larvae associated with reduced connectivity. We conclude that the existing MPA network is vulnerable to atmospheric-driven changes in ocean circulation.

The Importance of Actualistic Source-to-Sink Sand Provenance Studies in Illuminating the Nature of Ancient Fluvial Systems From the Deep-Marine Clastic Successions They Sourced

NASA Astrophysics Data System (ADS)

Marsaglia, K. M.; Parra, J. G.; Dawson, S.

2006-12-01

Successions of gravity-flow deposits in deep-marine fan systems have the potential to record the evolution of their fluvial source region as well as specific tectonic, climatic, eustatic and anthropogenic events. Deciphering these signals involves the description and quantification of key sediment attributes such as fan volume, the rate of sediment accumulation, the frequency of depositional events, sediment texture, and sediment composition. Sediment composition/provenance provides insight into the nature of the fluvial source, including drainage basin geology and drainage development. For example, Marsaglia et al. (1995) demonstrated a connection between source river lengthening owing to eustatic change and sand composition in Quaternary turbidite successions of the Santa Barbara Basin at Ocean Drilling Program (ODP) Site 893. In contrast, longer-term compositional trends recognized in the Mesozoic to Cenozoic rift-to-drift successions cored by various ODP legs on the North Atlantic margins are more likely associated with continental margin drainage development and fluvial system evolution (Marsaglia et al., in press). These two connections between sink and source were made possible by well-documented petrologic data sets for both modern onshore fluvial systems and older offshore deep-marine successions, but in each case different workers collected the onshore and offshore data sets. In the Waipaoa River Sedimentary System of North Island, New Zealand we have taken a different, more holistic approach, with a limited and linked group of researchers and sample data base covering the complete system. The study area is an active forearc margin characterized by uplifted and deformed sedimentary successions and periodic input of arc-derived ash. Recently, the modern onshore system has been thoroughly documented via studies of the petrology of outcropping Mesozoic to Cenozoic units, fluvial terrace deposits, and modern fluvial sediments (e.g., James et al., in press). Now we are building on that data set and moving from source-to-sink to trace sandy sediment through the system out onto the shelf and slope where it has been encountered in shallow cores. Lessons learned onshore, such as a distinct compositional dependence on grain size and the relationships of bedrock geology to certain sand grain types, also apply to these offshore core samples. Many of the sandy intervals are largely composed of reworked tephra from Taupo eruptions, whereas quartz and feldspar dominate finer sand samples. Lithic-dominated sands are less common and coarser grained. Isolated greywacke gravel clasts indicate that at some point coarse sediment "leaked" into the basin from the south. The volumetric importance of this extrabasinal input can be assessed by looking at the types and proportions of lithic fragments within the finer sand fraction.

Relating Enzyme Function to Concepts of Dominance and Recessiveness.

ERIC Educational Resources Information Center

Lanza, Janet; Cress, Camille

2001-01-01

Points out the difficulties students have in making connections from the DNA molecule to a phenotype. Presents an activity in which students imitate the actions of functional and nonfunctional enzymes and examine the phenotype of organisms of different genotypes. (YDS)

Social power, conflict policing, and the role of subordination signals in rhesus macaque society

PubMed Central

Beisner, Brianne A.; Hannibal, Darcy L.; Finn, Kelly R.; Fushing, Hsieh; McCowan, Brenda

2017-01-01

Objectives Policing is a conflict-limiting mechanism observed in many primate species. It is thought to require a skewed distribution of social power for some individuals to have sufficiently high social power to stop others’ fights, yet social power has not been examined in most species with policing behavior. We examined networks of subordination signals as a source of social power that permits policing behavior in rhesus macaques. Materials and Methods For each of seven captive groups of rhesus macaques, we (a) examined the structure of subordination signal networks and used GLMs to examine the relationship between (b) pairwise dominance certainty and subordination network pathways and (c) policing frequency and social power (group-level convergence in subordination signaling pathways). Results Networks of subordination signals had perfect linear transitivity, and pairs connected by both direct and indirect pathways of signals had more certain dominance relationships than pairs with no such network connection. Social power calculated using both direct and indirect network pathways showed a heavy-tailed distribution and positively predicted conflict policing. Conclusions Our results empirically substantiate that subordination signaling is associated with greater dominance relationship certainty and further show that pairs who signal rarely (or not at all) may use information from others’ signaling interactions to infer or reaffirm the relative certainty of their own relationships. We argue that the network of formal dominance relationships is central to societal stability because it is important for relationship stability and also supports the additional stabilizing mechanism of policing. PMID:26801956

Social power, conflict policing, and the role of subordination signals in rhesus macaque society.

PubMed

Beisner, Brianne A; Hannibal, Darcy L; Finn, Kelly R; Fushing, Hsieh; McCowan, Brenda

2016-05-01

Policing is a conflict-limiting mechanism observed in many primate species. It is thought to require a skewed distribution of social power for some individuals to have sufficiently high social power to stop others' fights, yet social power has not been examined in most species with policing behavior. We examined networks of subordination signals as a source of social power that permits policing behavior in rhesus macaques. For each of seven captive groups of rhesus macaques, we (a) examined the structure of subordination signal networks and used GLMs to examine the relationship between (b) pairwise dominance certainty and subordination network pathways and (c) policing frequency and social power (group-level convergence in subordination signaling pathways). Networks of subordination signals had perfect linear transitivity, and pairs connected by both direct and indirect pathways of signals had more certain dominance relationships than pairs with no such network connection. Social power calculated using both direct and indirect network pathways showed a heavy-tailed distribution and positively predicted conflict policing. Our results empirically substantiate that subordination signaling is associated with greater dominance relationship certainty and further show that pairs who signal rarely (or not at all) may use information from others' signaling interactions to infer or reaffirm the relative certainty of their own relationships. We argue that the network of formal dominance relationships is central to societal stability because it is important for relationship stability and also supports the additional stabilizing mechanism of policing. © 2016 Wiley Periodicals, Inc.

Modeling ecological minimum requirements for distribution of greater sage-grouse leks: implications for population connectivity across their western range, U.S.A.

PubMed

Knick, Steven T; Hanser, Steven E; Preston, Kristine L

2013-06-01

Greater sage-grouse Centrocercus urophasianus (Bonaparte) currently occupy approximately half of their historical distribution across western North America. Sage-grouse are a candidate for endangered species listing due to habitat and population fragmentation coupled with inadequate regulation to control development in critical areas. Conservation planning would benefit from accurate maps delineating required habitats and movement corridors. However, developing a species distribution model that incorporates the diversity of habitats used by sage-grouse across their widespread distribution has statistical and logistical challenges. We first identified the ecological minimums limiting sage-grouse, mapped similarity to the multivariate set of minimums, and delineated connectivity across a 920,000 km(2) region. We partitioned a Mahalanobis D (2) model of habitat use into k separate additive components each representing independent combinations of species-habitat relationships to identify the ecological minimums required by sage-grouse. We constructed the model from abiotic, land cover, and anthropogenic variables measured at leks (breeding) and surrounding areas within 5 km. We evaluated model partitions using a random subset of leks and historic locations and selected D (2) (k = 10) for mapping a habitat similarity index (HSI). Finally, we delineated connectivity by converting the mapped HSI to a resistance surface. Sage-grouse required sagebrush-dominated landscapes containing minimal levels of human land use. Sage-grouse used relatively arid regions characterized by shallow slopes, even terrain, and low amounts of forest, grassland, and agriculture in the surrounding landscape. Most populations were interconnected although several outlying populations were isolated because of distance or lack of habitat corridors for exchange. Land management agencies currently are revising land-use plans and designating critical habitat to conserve sage-grouse and avoid endangered species listing. Our results identifying attributes important for delineating habitats or modeling connectivity will facilitate conservation and management of landscapes important for supporting current and future sage-grouse populations.

Modeling ecological minimum requirements for distribution of greater sage-grouse leks: implications for population connectivity across their western range, U.S.A.

USGS Publications Warehouse

Knick, Steven T.; Hanser, Steven E.; Preston, Kristine L.

2013-01-01

Greater sage-grouse Centrocercus urophasianus (Bonaparte) currently occupy approximately half of their historical distribution across western North America. Sage-grouse are a candidate for endangered species listing due to habitat and population fragmentation coupled with inadequate regulation to control development in critical areas. Conservation planning would benefit from accurate maps delineating required habitats and movement corridors. However, developing a species distribution model that incorporates the diversity of habitats used by sage-grouse across their widespread distribution has statistical and logistical challenges. We first identified the ecological minimums limiting sage-grouse, mapped similarity to the multivariate set of minimums, and delineated connectivity across a 920,000 km2 region. We partitioned a Mahalanobis D2 model of habitat use into k separate additive components each representing independent combinations of species–habitat relationships to identify the ecological minimums required by sage-grouse. We constructed the model from abiotic, land cover, and anthropogenic variables measured at leks (breeding) and surrounding areas within 5 km. We evaluated model partitions using a random subset of leks and historic locations and selected D2 (k = 10) for mapping a habitat similarity index (HSI). Finally, we delineated connectivity by converting the mapped HSI to a resistance surface. Sage-grouse required sagebrush-dominated landscapes containing minimal levels of human land use. Sage-grouse used relatively arid regions characterized by shallow slopes, even terrain, and low amounts of forest, grassland, and agriculture in the surrounding landscape. Most populations were interconnected although several outlying populations were isolated because of distance or lack of habitat corridors for exchange. Land management agencies currently are revising land-use plans and designating critical habitat to conserve sage-grouse and avoid endangered species listing. Our results identifying attributes important for delineating habitats or modeling connectivity will facilitate conservation and management of landscapes important for supporting current and future sage-grouse populations.

Text vectorization based on character recognition and character stroke modeling

NASA Astrophysics Data System (ADS)

Fan, Zhigang; Zhou, Bingfeng; Tse, Francis; Mu, Yadong; He, Tao

2014-03-01

In this paper, a text vectorization method is proposed using OCR (Optical Character Recognition) and character stroke modeling. This is based on the observation that for a particular character, its font glyphs may have different shapes, but often share same stroke structures. Like many other methods, the proposed algorithm contains two procedures, dominant point determination and data fitting. The first one partitions the outlines into segments and second one fits a curve to each segment. In the proposed method, the dominant points are classified as "major" (specifying stroke structures) and "minor" (specifying serif shapes). A set of rules (parameters) are determined offline specifying for each character the number of major and minor dominant points and for each dominant point the detection and fitting parameters (projection directions, boundary conditions and smoothness). For minor points, multiple sets of parameters could be used for different fonts. During operation, OCR is performed and the parameters associated with the recognized character are selected. Both major and minor dominant points are detected as a maximization process as specified by the parameter set. For minor points, an additional step could be performed to test the competing hypothesis and detect degenerated cases.

Correlating subcortical interhemispheric connectivity and cortical hemispheric dominance in brain tumor patients: A repetitive navigated transcranial magnetic stimulation study.

PubMed

Sollmann, Nico; Ille, Sebastian; Tussis, Lorena; Maurer, Stefanie; Hauck, Theresa; Negwer, Chiara; Bauer, Jan S; Ringel, Florian; Meyer, Bernhard; Krieg, Sandro M

2016-02-01

The present study aims to investigate the relationship between transcallosal interhemispheric connectivity (IC) and hemispheric language lateralization by using a novel approach including repetitive navigated transcranial magnetic stimulation (rTMS), hemispheric dominance ratio (HDR) calculation, and rTMS-based diffusion tensor imaging fiber tracking (DTI FT). 31 patients with left-sided perisylvian brain lesions underwent diffusion tensor imaging (DTI) and rTMS language mapping. Cortical language-positive rTMS spots were used to calculate HDRs (HDR: quotient of the left-sided divided by right-sided naming error rates for corresponding left- and right-sided cortical regions) and to create regions of interest (ROIs) for DTI FT. Then, fibers connecting the rTMS-based ROIs of both hemispheres were tracked, and the correlation of IC to HDRs was calculated via Spearman's rank correlation coefficient (rs). Fibers connecting rTMS-based ROIs of both hemispheres were detected in 12 patients (38.7%). Within the patients in which IC was detected, the mean number of subcortical IC fibers ± standard deviation (SD) was 138.0 ± 346.5 (median: 7.5; range: 1-1,217 fibers). Regarding rs for the correlation of HDRs and fiber numbers of patients that showed IC, only moderate correlation was revealed. Our approach might be beneficial and technically feasible for further investigation of the relationship between IC and language lateralization. However, only moderate correlation was revealed in the present study. Copyright © 2015 Elsevier B.V. All rights reserved.

Effective brain network analysis with resting-state EEG data: a comparison between heroin abstinent and non-addicted subjects

NASA Astrophysics Data System (ADS)

Hu, Bin; Dong, Qunxi; Hao, Yanrong; Zhao, Qinglin; Shen, Jian; Zheng, Fang

2017-08-01

Objective. Neuro-electrophysiological tools have been widely used in heroin addiction studies. Previous studies indicated that chronic heroin abuse would result in abnormal functional organization of the brain, while few heroin addiction studies have applied the effective connectivity tool to analyze the brain functional system (BFS) alterations induced by heroin abuse. The present study aims to identify the abnormality of resting-state heroin abstinent BFS using source decomposition and effective connectivity tools. Approach. The resting-state electroencephalograph (EEG) signals were acquired from 15 male heroin abstinent (HA) subjects and 14 male non-addicted (NA) controls. Multivariate autoregressive models combined independent component analysis (MVARICA) was applied for blind source decomposition. Generalized partial directed coherence (GPDC) was applied for effective brain connectivity analysis. Effective brain networks of both HA and NA groups were constructed. The two groups of effective cortical networks were compared by the bootstrap method. Abnormal causal interactions between decomposed source regions were estimated in the 1-45 Hz frequency domain. Main results. This work suggested: (a) there were clear effective network alterations in heroin abstinent subject groups; (b) the parietal region was a dominant hub of the abnormally weaker causal pathways, and the left occipital region was a dominant hub of the abnormally stronger causal pathways. Significance. These findings provide direct evidence that chronic heroin abuse induces brain functional abnormalities. The potential value of combining effective connectivity analysis and brain source decomposition methods in exploring brain alterations of heroin addicts is also implied.

Effective brain network analysis with resting-state EEG data: a comparison between heroin abstinent and non-addicted subjects.

PubMed

Hu, Bin; Dong, Qunxi; Hao, Yanrong; Zhao, Qinglin; Shen, Jian; Zheng, Fang

2017-08-01

Neuro-electrophysiological tools have been widely used in heroin addiction studies. Previous studies indicated that chronic heroin abuse would result in abnormal functional organization of the brain, while few heroin addiction studies have applied the effective connectivity tool to analyze the brain functional system (BFS) alterations induced by heroin abuse. The present study aims to identify the abnormality of resting-state heroin abstinent BFS using source decomposition and effective connectivity tools. The resting-state electroencephalograph (EEG) signals were acquired from 15 male heroin abstinent (HA) subjects and 14 male non-addicted (NA) controls. Multivariate autoregressive models combined independent component analysis (MVARICA) was applied for blind source decomposition. Generalized partial directed coherence (GPDC) was applied for effective brain connectivity analysis. Effective brain networks of both HA and NA groups were constructed. The two groups of effective cortical networks were compared by the bootstrap method. Abnormal causal interactions between decomposed source regions were estimated in the 1-45 Hz frequency domain. This work suggested: (a) there were clear effective network alterations in heroin abstinent subject groups; (b) the parietal region was a dominant hub of the abnormally weaker causal pathways, and the left occipital region was a dominant hub of the abnormally stronger causal pathways. These findings provide direct evidence that chronic heroin abuse induces brain functional abnormalities. The potential value of combining effective connectivity analysis and brain source decomposition methods in exploring brain alterations of heroin addicts is also implied.

Identifying group discriminative and age regressive sub-networks from DTI-based connectivity via a unified framework of non-negative matrix factorization and graph embedding

PubMed Central

Ghanbari, Yasser; Smith, Alex R.; Schultz, Robert T.; Verma, Ragini

2014-01-01

Diffusion tensor imaging (DTI) offers rich insights into the physical characteristics of white matter (WM) fiber tracts and their development in the brain, facilitating a network representation of brain’s traffic pathways. Such a network representation of brain connectivity has provided a novel means of investigating brain changes arising from pathology, development or aging. The high dimensionality of these connectivity networks necessitates the development of methods that identify the connectivity building blocks or sub-network components that characterize the underlying variation in the population. In addition, the projection of the subject networks into the basis set provides a low dimensional representation of it, that teases apart different sources of variation in the sample, facilitating variation-specific statistical analysis. We propose a unified framework of non-negative matrix factorization and graph embedding for learning sub-network patterns of connectivity by their projective non-negative decomposition into a reconstructive basis set, as well as, additional basis sets representing variational sources in the population like age and pathology. The proposed framework is applied to a study of diffusion-based connectivity in subjects with autism that shows localized sparse sub-networks which mostly capture the changes related to pathology and developmental variations. PMID:25037933

Fish communities in coastal freshwater ecosystems: the role of the physical and chemical setting.

PubMed

Arend, Kristin K; Bain, Mark B

2008-12-29

We explored how embayment watershed inputs, morphometry, and hydrology influence fish community structure among eight embayments located along the southeastern shoreline of Lake Ontario, New York, USA. Embayments differed in surface area and depth, varied in their connections to Lake Ontario and their watersheds, and drained watersheds representing a gradient of agricultural to forested land use. We related various physicochemical factors, including total phosphorus load, embayment area, and submerged vegetation, to differences in fish species diversity and community relative abundance, biomass, and size structure both among and within embayments. Yellow perch (Perca flavescens) and centrarchids numerically dominated most embayment fish communities. Biomass was dominated by piscivorous fishes including brown bullhead (Ameiurus nebulosus), bowfin (Amia calva), and northern pike (Esox lucius). Phosphorus loading influenced relative biomass, but not species diversity or relative abundance. Fish relative abundance differed among embayments; within embayments, fish abundance at individual sampling stations increased significantly with submerged vegetative cover. Relative biomass differed among embayments and was positively related to total phophorus loading and embayment area. Fish community size structure, based on size spectra analysis, differed among embayments, with the frequency of smaller-bodied fishes positively related to percent vegetation. The importance of total phosphorus loading and vegetation in structuring fish communities has implications for anthropogenic impacts to embayment fish communities through activities such as farming and residential development, reduction of cultural eutrophication, and shoreline development and maintenance.

What metrics best reflect the energy and carbon intensity of cities? Insights from theory and modeling of 20 US cities

NASA Astrophysics Data System (ADS)

Ramaswami, Anu; Chavez, Abel

2013-09-01

Three broad approaches have emerged for energy and greenhouse gas (GHG) accounting for individual cities: (a) purely in-boundary source-based accounting (IB); (b) community-wide infrastructure GHG emissions footprinting (CIF) incorporating life cycle GHGs (in-boundary plus trans-boundary) of key infrastructures providing water, energy, food, shelter, mobility-connectivity, waste management/sanitation and public amenities to support community-wide activities in cities—all resident, visitor, commercial and industrial activities; and (c) consumption-based GHG emissions footprints (CBF) incorporating life cycle GHGs associated with activities of a sub-set of the community—its final consumption sector dominated by resident households. The latter two activity-based accounts are recommended in recent GHG reporting standards, to provide production-dominated and consumption perspectives of cities, respectively. Little is known, however, on how to normalize and report the different GHG numbers that arise for the same city. We propose that CIF and IB, since they incorporate production, are best reported per unit GDP, while CBF is best reported per capita. Analysis of input-output models of 20 US cities shows that GHGCIF/GDP is well suited to represent differences in urban energy intensity features across cities, while GHGCBF/capita best represents variation in expenditures across cities. These results advance our understanding of the methods and metrics used to represent the energy and GHG performance of cities.

New Ways in Teaching Connected Speech. New Ways Series

ERIC Educational Resources Information Center

Brown, James Dean, Ed.

2012-01-01

Connected speech is based on a set of rules used to modify pronunciations so that words connect and flow more smoothly in natural speech (hafta versus have to). Native speakers of English tend to feel that connected speech is friendlier, more natural, more sympathetic, and more personal. Is there any reason why learners of English would prefer to…

Steel Rack Connections: Identification of Most Influential Factors and a Comparison of Stiffness Design Methods

PubMed Central

Shah, S. N. R.; Sulong, N. H. Ramli; Shariati, Mahdi; Jumaat, M. Z.

2015-01-01

Steel pallet rack (SPR) beam-to-column connections (BCCs) are largely responsible to avoid the sway failure of frames in the down-aisle direction. The overall geometry of beam end connectors commercially used in SPR BCCs is different and does not allow a generalized analytic approach for all types of beam end connectors; however, identifying the effects of the configuration, profile and sizes of the connection components could be the suitable approach for the practical design engineers in order to predict the generalized behavior of any SPR BCC. This paper describes the experimental behavior of SPR BCCs tested using a double cantilever test set-up. Eight sets of specimens were identified based on the variation in column thickness, beam depth and number of tabs in the beam end connector in order to investigate the most influential factors affecting the connection performance. Four tests were repeatedly performed for each set to bring uniformity to the results taking the total number of tests to thirty-two. The moment-rotation (M-θ) behavior, load-strain relationship, major failure modes and the influence of selected parameters on connection performance were investigated. A comparative study to calculate the connection stiffness was carried out using the initial stiffness method, the slope to half-ultimate moment method and the equal area method. In order to find out the more appropriate method, the mean stiffness of all the tested connections and the variance in values of mean stiffness according to all three methods were calculated. The calculation of connection stiffness by means of the initial stiffness method is considered to overestimate the values when compared to the other two methods. The equal area method provided more consistent values of stiffness and lowest variance in the data set as compared to the other two methods. PMID:26452047

Energy-efficient algorithm for broadcasting in ad hoc wireless sensor networks.

PubMed

Xiong, Naixue; Huang, Xingbo; Cheng, Hongju; Wan, Zheng

2013-04-12

Broadcasting is a common and basic operation used to support various network protocols in wireless networks. To achieve energy-efficient broadcasting is especially important for ad hoc wireless sensor networks because sensors are generally powered by batteries with limited lifetimes. Energy consumption for broadcast operations can be reduced by minimizing the number of relay nodes based on the observation that data transmission processes consume more energy than data reception processes in the sensor nodes, and how to improve the network lifetime is always an interesting issue in sensor network research. The minimum-energy broadcast problem is then equivalent to the problem of finding the minimum Connected Dominating Set (CDS) for a connected graph that is proved NP-complete. In this paper, we introduce an Efficient Minimum CDS algorithm (EMCDS) with help of a proposed ordered sequence list. EMCDS does not concern itself with node energy and broadcast operations might fail if relay nodes are out of energy. Next we have proposed a Minimum Energy-consumption Broadcast Scheme (MEBS) with a modified version of EMCDS, and aimed at providing an efficient scheduling scheme with maximized network lifetime. The simulation results show that the proposed EMCDS algorithm can find smaller CDS compared with related works, and the MEBS can help to increase the network lifetime by efficiently balancing energy among nodes in the networks.

Hollywood Now.

ERIC Educational Resources Information Center

Fadiman, William

A behind-the-scenes look at Hollywood's film industry reveals the roles and functions of its agents, directors, stars, writers, producers, and technicians. Economy is the dominant motivational factor affecting everyone connected with Hollywood; actors, scripts, and film production specialists are evaluated entirely in dollars. Coping with this…

Dominant Discourses in Curriculum

ERIC Educational Resources Information Center

Miller, Elizabeth

2012-01-01

In the following paper, the author draws upon the works of critical theorists and critical curriculum scholars to investigate the intersection of the social and political realms with contemporary educational and curricular trends. This paper specifically explores connections between current curriculum trends with neutrality, social reproduction,…

76 FR 61052 - Service Standards for Market-Dominant Special Services Products

Federal Register 2010, 2011, 2012, 2013, 2014

2011-10-03

... POSTAL SERVICE 39 CFR Part 122 Service Standards for Market-Dominant Special Services Products... products set forth in our regulations. DATES: Effective date: November 2, 2011. FOR FURTHER INFORMATION... Service to establish modern service standards for its market-dominant products within a year of the law's...

Multiscale fracture network characterization and impact on flow: A case study on the Latemar carbonate platform

NASA Astrophysics Data System (ADS)

Hardebol, N. J.; Maier, C.; Nick, H.; Geiger, S.; Bertotti, G.; Boro, H.

2015-12-01

A fracture network arrangement is quantified across an isolated carbonate platform from outcrop and aerial imagery to address its impact on fluid flow. The network is described in terms of fracture density, orientation, and length distribution parameters. Of particular interest is the role of fracture cross connections and abutments on the effective permeability. Hence, the flow simulations explicitly account for network topology by adopting Discrete-Fracture-and-Matrix description. The interior of the Latemar carbonate platform (Dolomites, Italy) is taken as outcrop analogue for subsurface reservoirs of isolated carbonate build-ups that exhibit a fracture-dominated permeability. New is our dual strategy to describe the fracture network both as deterministic- and stochastic-based inputs for flow simulations. The fracture geometries are captured explicitly and form a multiscale data set by integration of interpretations from outcrops, airborne imagery, and lidar. The deterministic network descriptions form the basis for descriptive rules that are diagnostic of the complex natural fracture arrangement. The fracture networks exhibit a variable degree of multitier hierarchies with smaller-sized fractures abutting against larger fractures under both right and oblique angles. The influence of network topology on connectivity is quantified using Discrete-Fracture-Single phase fluid flow simulations. The simulation results show that the effective permeability for the fracture and matrix ensemble can be 50 to 400 times higher than the matrix permeability of 1.0 · 10-14 m2. The permeability enhancement is strongly controlled by the connectivity of the fracture network. Therefore, the degree of intersecting and abutting fractures should be captured from outcrops with accuracy to be of value as analogue.

Synchronous high-frequency oscillations in inhibitory-dominant network motifs consisting of three dentate gyrus-CA3 systems

NASA Astrophysics Data System (ADS)

Zhang, Liyuan; Fan, Denggui; Wang, Qingyun

2018-06-01

Studies on the structural-functional connectomes of the human brain have demonstrated the existence of synchronous firings in a specific brain network motif. In particular, synchronization of high-frequency oscillations (HFOs) has been observed in the experimental data sets of temporal lobe epilepsy (TLE). In addition, both clinical and experimental evidences have accumulated to demonstrate the effect of electrical stimulation on TLE, which, however, remains largely unexplored. In this work, we first employ our previously proposed dentate gyrus (DG)-CA3 network model to investigate the influence of an external electrical stimulus on the HFO transitions. The results indicate that the reinforcing stimulus can induce the HFO transitions of the DG-CA3 system from the gamma band to the fast ripples band. Along with that, the consistent oscillations of neurons within DG-CA3 can also be enhanced with the increasing of stimulus. Then, we expand into a simple motif of three coupled DG-CA3 systems in both the feedforward inhibition and feedback inhibition connections, to investigate the synchronous evolutions of HFOs by regulating both the stimulation strength and inhibitory function. It is shown that the comprehensive effects, which lead to band transition, are independent of the motif configurations. The enhanced external electrical stimulus weakens the synchronism and correlation of connected motifs. In contrast, we demonstrate that the increased inhibitory coupling could facilitate correlation to some extent. Overall, our work highlights the possible origin of synchronous HFOs of hippocampal motifs governed by external inputs and inhibitory connection, which might contribute to a better understanding of the interplay between synchronization dynamics and epileptic structure in the human brain.

Brain properties predict proximity to symptom onset in sporadic Alzheimer's disease.

PubMed

Vogel, Jacob W; Vachon-Presseau, Etienne; Pichet Binette, Alexa; Tam, Angela; Orban, Pierre; La Joie, Renaud; Savard, Mélissa; Picard, Cynthia; Poirier, Judes; Bellec, Pierre; Breitner, John C S; Villeneuve, Sylvia

2018-06-01

See Tijms and Visser (doi:10.1093/brain/awy113) for a scientific commentary on this article.Alzheimer's disease is preceded by a lengthy 'preclinical' stage spanning many years, during which subtle brain changes occur in the absence of overt cognitive symptoms. Predicting when the onset of disease symptoms will occur is an unsolved challenge in individuals with sporadic Alzheimer's disease. In individuals with autosomal dominant genetic Alzheimer's disease, the age of symptom onset is similar across generations, allowing the prediction of individual onset times with some accuracy. We extend this concept to persons with a parental history of sporadic Alzheimer's disease to test whether an individual's symptom onset age can be informed by the onset age of their affected parent, and whether this estimated onset age can be predicted using only MRI. Structural and functional MRIs were acquired from 255 ageing cognitively healthy subjects with a parental history of sporadic Alzheimer's disease from the PREVENT-AD cohort. Years to estimated symptom onset was calculated as participant age minus age of parental symptom onset. Grey matter volume was extracted from T1-weighted images and whole-brain resting state functional connectivity was evaluated using degree count. Both modalities were summarized using a 444-region cortical-subcortical atlas. The entire sample was divided into training (n = 138) and testing (n = 68) sets. Within the training set, individuals closer to or beyond their parent's symptom onset demonstrated reduced grey matter volume and altered functional connectivity, specifically in regions known to be vulnerable in Alzheimer's disease. Machine learning was used to identify a weighted set of imaging features trained to predict years to estimated symptom onset. This feature set alone significantly predicted years to estimated symptom onset in the unseen testing data. This model, using only neuroimaging features, significantly outperformed a similar model instead trained with cognitive, genetic, imaging and demographic features used in a traditional clinical setting. We next tested if these brain properties could be generalized to predict time to clinical progression in a subgroup of 26 individuals from the Alzheimer's Disease Neuroimaging Initiative, who eventually converted either to mild cognitive impairment or to Alzheimer's dementia. The feature set trained on years to estimated symptom onset in the PREVENT-AD predicted variance in time to clinical conversion in this separate longitudinal dataset. Adjusting for participant age did not impact any of the results. These findings demonstrate that years to estimated symptom onset or similar measures can be predicted from brain features and may help estimate presymptomatic disease progression in at-risk individuals.

Self-face recognition shares brain regions active during proprioceptive illusion in the right inferior fronto-parietal superior longitudinal fasciculus III network.

PubMed

Morita, Tomoyo; Saito, Daisuke N; Ban, Midori; Shimada, Koji; Okamoto, Yuko; Kosaka, Hirotaka; Okazawa, Hidehiko; Asada, Minoru; Naito, Eiichi

2017-04-21

Proprioception is somatic sensation that allows us to sense and recognize position, posture, and their changes in our body parts. It pertains directly to oneself and may contribute to bodily awareness. Likewise, one's face is a symbol of oneself, so that visual self-face recognition directly contributes to the awareness of self as distinct from others. Recently, we showed that right-hemispheric dominant activity in the inferior fronto-parietal cortices, which are connected by the inferior branch of the superior longitudinal fasciculus (SLF III), is associated with proprioceptive illusion (awareness), in concert with sensorimotor activity. Herein, we tested the hypothesis that visual self-face recognition shares brain regions active during proprioceptive illusion in the right inferior fronto-parietal SLF III network. We scanned brain activity using functional magnetic resonance imaging while twenty-two right-handed healthy adults performed two tasks. One was a proprioceptive illusion task, where blindfolded participants experienced a proprioceptive illusion of right hand movement. The other was a visual self-face recognition task, where the participants judged whether an observed face was their own. We examined whether the self-face recognition and the proprioceptive illusion commonly activated the inferior fronto-parietal cortices connected by the SLF III in a right-hemispheric dominant manner. Despite the difference in sensory modality and in the body parts involved in the two tasks, both tasks activated the right inferior fronto-parietal cortices, which are likely connected by the SLF III, in a right-side dominant manner. Here we discuss possible roles for right inferior fronto-parietal activity in bodily awareness and self-awareness. Copyright © 2017 The Author(s). Published by Elsevier Ltd.. All rights reserved.

Digital data sets that describe aquifer characteristics of the alluvial and terrace deposits along the North Canadian River from Canton Lake to Lake Overholser in Central Oklahoma

USGS Publications Warehouse

Adams, G.P.; Rea, Alan; Runkle, D.L.

1997-01-01

ARC/INFO export and nonproprietary format files This diskette contains digitized aquifer boundaries and maps of of hydraulic conductivity, recharge, and ground-water level elevation contours for the alluvial and terrace deposits along the alluvial and terrace deposits along the North Canadian River from Canton Lake to Lake Overholser in central Oklahoma. Ground water in approximately 400 square miles of Quaternary-age alluvial and terrace aquifer is an important source of water for irrigation, industrial, municipal, stock, and domestic supplies. The aquifer consists of clay, silt, sand, and gravel. Sand-sized sediments dominate the poorly sorted, fine to coarse, unconsolidated quartz grains in the aquifer. The hydraulically connected alluvial and terrace deposits unconformably overlie Permian-age formations. The aquifer is overlain by a layer of wind-blown sand in parts of the area. Most of the lines in the aquifer boundary, hydraulic conductivity, and recharge data sets were extracted from published digital surficial geology data sets based on a scale of 1:250,000. The ground-water elevation contours and some of the lines for the aquifer boundary, hydraulic conductivity, and recharge data sets were digitized from a ground-water modeling report about the aquifer published at a scale of 1:250,000. The hydraulic conductivity values and recharge rates also are from the ground-water modeling report. Ground-water flow models are numerical representations that simplify and aggregate natural systems. Models are not unique; different combinations of aquifer characteristics may produce similar results. Therefore, values of hydraulic conductivity and recharge used in the model and presented in this data set are not precise, but are within a reasonable range when compared to independently collected data.

Three-dimensional coil inductor

DOEpatents

Bernhardt, Anthony F.; Malba, Vincent

2002-01-01

A three-dimensional coil inductor is disclosed. The inductor includes a substrate; a set of lower electrically conductive traces positioned on the substrate; a core placed over the lower traces; a set of side electrically conductive traces laid on the core and the lower traces; and a set of upper electrically conductive traces attached to the side traces so as to form the inductor. Fabrication of the inductor includes the steps of forming a set of lower traces on a substrate; positioning a core over the lower traces; forming a set of side traces on the core; connecting the side traces to the lower traces; forming a set of upper traces on the core; and connecting the upper traces to the side traces so as to form a coil structure.

Lateralized theta wave connectivity and language performance in 2- to 5-year-old children.

PubMed

Kikuchi, Mitsuru; Shitamichi, Kiyomi; Yoshimura, Yuko; Ueno, Sanae; Remijn, Gerard B; Hirosawa, Tetsu; Munesue, Toshio; Tsubokawa, Tsunehisa; Haruta, Yasuhiro; Oi, Manabu; Higashida, Haruhiro; Minabe, Yoshio

2011-10-19

Recent neuroimaging studies support the view that a left-lateralized brain network is crucial for language development in children. However, no previous studies have demonstrated a clear link between lateralized brain functional network and language performance in preschool children. Magnetoencephalography (MEG) is a noninvasive brain imaging technique and is a practical neuroimaging method for use in young children. MEG produces a reference-free signal, and is therefore an ideal tool to compute coherence between two distant cortical rhythms. In the present study, using a custom child-sized MEG system, we investigated brain networks while 78 right-handed preschool human children (32-64 months; 96% were 3-4 years old) listened to stories with moving images. The results indicated that left dominance of parietotemporal coherence in theta band activity (6-8 Hz) was specifically correlated with higher performance of language-related tasks, whereas this laterality was not correlated with nonverbal cognitive performance, chronological age, or head circumference. Power analyses did not reveal any specific frequencies that contributed to higher language performance. Our results suggest that it is not the left dominance in theta oscillation per se, but the left-dominant phase-locked connectivity via theta oscillation that contributes to the development of language ability in young children.

Neurological impressions on the organization of language networks in the human brain.

PubMed

Oliveira, Fabricio Ferreira de; Marin, Sheilla de Medeiros Correia; Bertolucci, Paulo Henrique Ferreira

2017-01-01

More than 95% of right-handed individuals, as well as almost 80% of left-handed individuals, have left hemisphere dominance for language. The perisylvian networks of the dominant hemisphere tend to be the most important language systems in human brains, usually connected by bidirectional fibres originated from the superior longitudinal fascicle/arcuate fascicle system and potentially modifiable by learning. Neuroplasticity mechanisms take place to preserve neural functions after brain injuries. Language is dependent on a hierarchical interlinkage of serial and parallel processing areas in distinct brain regions considered to be elementary processing units. Whereas aphasic syndromes typically result from injuries to the dominant hemisphere, the extent of the distribution of language functions seems to be variable for each individual. Review of the literature Results: Several theories try to explain the organization of language networks in the human brain from a point of view that involves either modular or distributed processing or sometimes both. The most important evidence for each approach is discussed under the light of modern theories of organization of neural networks. Understanding the connectivity patterns of language networks may provide deeper insights into language functions, supporting evidence-based rehabilitation strategies that focus on the enhancement of language organization for patients with aphasic syndromes.

Climate shapes the protein abundance of dominant soil bacteria.

PubMed

Bastida, Felipe; Crowther, Tom W; Prieto, Iván; Routh, Devin; García, Carlos; Jehmlich, Nico

2018-05-28

Sensitive models of climate change impacts would require a better integration of multi-omics approaches that connect the abundance and activity of microbial populations. Here, we show that climate is a fundamental driver of the protein abundance of Actinobacteria, Planctomycetes and Proteobacteria, supporting the hypothesis that metabolic activity of some dominant phyla may be closely linked to climate. These results may improve our capacity to construct microbial models that better predict the impact of climate change in ecosystem processes. Copyright © 2018 Elsevier B.V. All rights reserved.

End Point of Black Ring Instabilities and the Weak Cosmic Censorship Conjecture.

PubMed

Figueras, Pau; Kunesch, Markus; Tunyasuvunakool, Saran

2016-02-19

We produce the first concrete evidence that violation of the weak cosmic censorship conjecture can occur in asymptotically flat spaces of five dimensions by numerically evolving perturbed black rings. For certain thin rings, we identify a new, elastic-type instability dominating the evolution, causing the system to settle to a spherical black hole. However, for sufficiently thin rings the Gregory-Laflamme mode is dominant, and the instability unfolds similarly to that of black strings, where the horizon develops a structure of bulges connected by necks which become ever thinner over time.

Motion of the drawing hand induces a progressive increase in muscle activity of the non-dominant hand in Ramachandran's mirror-box therapy.

PubMed

Furukawa, Kiminobu; Suzuki, Harue; Fukuda, Jun

2012-11-01

To observe the real-time muscle activity of bilateral hands while subjects draw circles under 2 conditions: with and without using Ramachandran's mirror-box. A total of 24 healthy volunteers. Subjects drew 4 circles sequentially using their dominant hand with the other hand at rest, both with and without looking at a mirror image. Circles were marked by 8 dots on the paper, which subjects connected up to draw the shape. The activity of the bilateral first dorsal interosseus muscles was recorded using surface electromyography. Muscle activity of the dominant hand remained constant during each task. In contrast, muscle activity of the non-dominant hand increased under the condition of watching the image in the mirror, but was low under the non-watching condition. Furthermore, muscle activity of the non-dominant hand increased over the duration of the task. However, wide variation between subjects was observed under the mirror-image condition. Increased muscle action potential of the non-dominant hand may be induced by the circle drawing task of the dominant hand during Ramachandran's mirror-box therapy, which supports previous observations of increased brain activity caused by watching a mirror image.

Hydrologic connection between ponds positively affects macrophyte alpha and gamma diversity but negatively affects beta diversity.

PubMed

Akasaka, Munemitsu; Takamura, Noriko

2012-05-01

Connections between habitat patches can positively influence the number of species in respective patches, providing a basis for preferentially conserving interconnected patches. However, from a regional perspective, it is not known whether conserving multiple sets of interconnected habitat patches would include more species (i.e., show higher gamma diversity) than conserving multiple, unconnected, solitary patches. We studied aquatic macrophytes in 15 sets of unidirectionally interconnected ponds and 19 unconnected ponds and also tested whether alpha and beta diversity, expressed as the number of species and dissimilarity in species composition, respectively, differed between connected and unconnected ponds. We found that gamma diversity was higher in connected ponds than in unconnected ponds, even after controlling for surface area. This resulted from a higher alpha diversity in connected ponds, despite lower beta diversity. These results suggest that connections between habitat patches positively influence diversity at both local and regional scales. When the total surface area available for conservation is limited, interconnected habitat patches should be preferentially conserved.

Exploring the Social Connections in Preschool Settings between Children Labelled with Special Educational Needs and Their Peers

ERIC Educational Resources Information Center

Parry, John

2015-01-01

This paper reports on a small-scale study of the social interactions between six children labelled with special educational needs and their peers in their respective early years settings. Data from play observations, photographs and staff interviews is used to examine the dynamics of the connections that they make with other children. The position…

Oceanography and life history predict contrasting genetic population structure in two Antarctic fish species

PubMed Central

Young, Emma F; Belchier, Mark; Hauser, Lorenz; Horsburgh, Gavin J; Meredith, Michael P; Murphy, Eugene J; Pascoal, Sonia; Rock, Jennifer; Tysklind, Niklas; Carvalho, Gary R

2015-01-01

Understanding the key drivers of population connectivity in the marine environment is essential for the effective management of natural resources. Although several different approaches to evaluating connectivity have been used, they are rarely integrated quantitatively. Here, we use a ‘seascape genetics’ approach, by combining oceanographic modelling and microsatellite analyses, to understand the dominant influences on the population genetic structure of two Antarctic fishes with contrasting life histories, Champsocephalus gunnari and Notothenia rossii. The close accord between the model projections and empirical genetic structure demonstrated that passive dispersal during the planktonic early life stages is the dominant influence on patterns and extent of genetic structuring in both species. The shorter planktonic phase of C. gunnari restricts direct transport of larvae between distant populations, leading to stronger regional differentiation. By contrast, geographic distance did not affect differentiation in N. rossii, whose longer larval period promotes long-distance dispersal. Interannual variability in oceanographic flows strongly influenced the projected genetic structure, suggesting that shifts in circulation patterns due to climate change are likely to impact future genetic connectivity and opportunities for local adaptation, resilience and recovery from perturbations. Further development of realistic climate models is required to fully assess such potential impacts. PMID:26029262

Generalized network modeling of capillary-dominated two-phase flow

NASA Astrophysics Data System (ADS)

Raeini, Ali Q.; Bijeljic, Branko; Blunt, Martin J.

2018-02-01

We present a generalized network model for simulating capillary-dominated two-phase flow through porous media at the pore scale. Three-dimensional images of the pore space are discretized using a generalized network—described in a companion paper [A. Q. Raeini, B. Bijeljic, and M. J. Blunt, Phys. Rev. E 96, 013312 (2017), 10.1103/PhysRevE.96.013312]—which comprises pores that are divided into smaller elements called half-throats and subsequently into corners. Half-throats define the connectivity of the network at the coarsest level, connecting each pore to half-throats of its neighboring pores from their narrower ends, while corners define the connectivity of pore crevices. The corners are discretized at different levels for accurate calculation of entry pressures, fluid volumes, and flow conductivities that are obtained using direct simulation of flow on the underlying image. This paper discusses the two-phase flow model that is used to compute the averaged flow properties of the generalized network, including relative permeability and capillary pressure. We validate the model using direct finite-volume two-phase flow simulations on synthetic geometries, and then present a comparison of the model predictions with a conventional pore-network model and experimental measurements of relative permeability in the literature.

Application of interleaved flyback micro inverter in a grid connected system

NASA Astrophysics Data System (ADS)

Brindha, R.; Ananthichristy, A.; Poornima, P. U.; Madhana, M.; Ashok Rathish, S.; Ragavi, Selvam

2018-04-01

The two control strategies CCM and DCM have various effects on the loss distribution and efficiency and thus were studied for the interleaved flyback micro inverter concentrating on the loss analysis under different load conditions. The dominant losses with heavy load include the conduction loss and the transformer loss in case of the interleaved flyback micro inverter; whereas driving of gate loss, the turn-off loss in the transformer core loss and in the powermosfets are included in the dominant losses with light load. A new hybrid control strategy which has the one-phase DCM and two-phase DCM control reduces the dominant losses in order to improving the efficiency based on the load in wide load range is proposed here.

Mina: A Th2 response regulator meets TGFβ

PubMed Central

Pillai, Meenu R.; Lian, Shangli; Bix, Mark

2014-01-01

The JmjC protein Mina is an important immune response regulator. Classical forward genetics first discovered its immune role in 2009 in connection with the development of T helper 2 (Th2) cells. This prompted investigation into Mina’s role in the two best-studied contexts where Th2 responses are essential: atopic asthma and helminth expulsion. In work focused on a mouse model of atopic asthma, Mina deficiency was found to ameliorate airway hyper-resistance and pulmonary inflammation. And, in a case-control study genetic variation at the human MINA locus was found to be associated with the development of childhood atopic asthma. Although the underlying cellular and molecular mechanism of Mina’s involvement in pulmonary inflammation remains unknown, our recent work on parasitic helminth expulsion suggests the possibility that, rather than T cells, epithelial cells responding to TGFβ may play the dominant role. Here we review the growing body of literature on the emerging Mina pathway in T cells and epithelial cells and attempt to set these into a broader context. PMID:25282476

Problem of two-level hierarchical minimax program control the final state of regional social and economic system in the presence of risks

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shorikov, A. F., E-mail: afshorikov@mail.ru

This article discusses a discrete-time dynamical system consisting of a set a controllable objects (region and forming it municipalities). The dynamics each of these is described by the corresponding vector nonlinear discrete-time recurrent vector equations and its control system consist from two levels: basic (control level I) that is dominating and subordinate level (control level II). Both levels have different criterions of functioning and united a priori by determined informational and control connections defined in advance. In this paper we study the problem of optimization of guaranteed result for program control by the final state of regional social and economicmore » system in the presence of risks. For this problem we proposed in this work an economical and mathematical model of two-level hierarchical minimax program control the final state of regional social and economic system in the presence of risks and the general scheme for its solving.« less

Problem of two-level hierarchical minimax program control the final state of regional social and economic system with incomplete information

NASA Astrophysics Data System (ADS)

Shorikov, A. F.

2016-12-01

In this article we consider a discrete-time dynamical system consisting of a set a controllable objects (region and forming it municipalities). The dynamics each of these is described by the corresponding linear or nonlinear discrete-time recurrent vector relations and its control system consist from two levels: basic level (control level I) that is dominating level and auxiliary level (control level II) that is subordinate level. Both levels have different criterions of functioning and united by information and control connections which defined in advance. In this article we study the problem of optimization of guaranteed result for program control by the final state of regional social and economic system in the presence of risks vectors. For this problem we propose a mathematical model in the form of two-level hierarchical minimax program control problem of the final states of this system with incomplete information and the general scheme for its solving.

Unveiling the structural arrangements responsible for the atomic dynamics in metallic glasses during physical aging

NASA Astrophysics Data System (ADS)

Giordano, V. M.; Ruta, B.

2016-01-01

Understanding and controlling physical aging, that is, the spontaneous temporal evolution of out-of-equilibrium systems, represents one of the greatest tasks in material science. Recent studies have revealed the existence of a complex atomic motion in metallic glasses, with different aging regimes in contrast with the typical continuous aging observed in macroscopic quantities. By combining dynamical and structural synchrotron techniques, here for the first time we directly connect previously identified microscopic structural mechanisms with the peculiar atomic motion, providing a broader unique view of their complexity. We show that the atomic scale is dominated by the interplay between two processes: rearrangements releasing residual stresses related to a cascade mechanism of relaxation, and medium range ordering processes, which do not affect the local density, likely due to localized relaxations of liquid-like regions. As temperature increases, a surprising additional secondary relaxation process sets in, together with a faster medium range ordering, likely precursors of crystallization.

Learning through ferroelectric domain dynamics in solid-state synapses

DOE Office of Scientific and Technical Information (OSTI.GOV)

Boyn, Soren; Grollier, Julie; Lecerf, Gwendal

In the brain, learning is achieved through the ability of synapses to reconfigure the strength by which they connect neurons (synaptic plasticity). In promising solid-state synapses called memristors, conductance can be finely tuned by voltage pulses and set to evolve according to a biological learning rule called spike-timing-dependent plasticity (STDP). Future neuromorphic architectures will comprise billions of such nanosynapses, which require a clear understanding of the physical mechanisms responsible for plasticity. Here we report on synapses based on ferroelectric tunnel junctions and show that STDP can be harnessed from inhomogeneous polarization switching. Through combined scanning probe imaging, electrical transport andmore » atomic-scale molecular dynamics, we demonstrate that conductance variations can be modelled by the nucleation-dominated reversal of domains. Finally, based on this physical model, our simulations show that arrays of ferroelectric nanosynapses can autonomously learn to recognize patterns in a predictable way, opening the path towards unsupervised learning in spiking neural networks.« less

Creating New Technologists of Research in the 1960s: The Case of the Reproduction of Automated Chromatography Specialists and Practitioners

NASA Astrophysics Data System (ADS)

Gerontas, Apostolos

2014-08-01

Chromatographic instrumentation has been really influential in shaping the modern chemical practice, and yet it has been largely overlooked by history of science.Gas chromatography in the 1960s was considered the analytical technique closer to becoming dominant, and being the first automated chromatography set the standards that all the subsequent chromatographic instrumentation had to fulfill. Networks of specialists, groups of actors, corporate strategies and the analytical practice itself, were all affected and in many ways because of the entrance of gas chromatography in the chemical laboratory and in the instrumentation market. This paper gives a view of the early history of the gas chromatography instrumentation, relates it to the broader research-technology phenomenon and discusses issues of education and group reproduction in the case of the groups of technologists of the era. The chaotic elements of knowledge transfer during the instrumentation revolution in chemistry are being highlighted and they are being connected to the observable radical innovation of the period.

Learning through ferroelectric domain dynamics in solid-state synapses

DOE PAGES

Boyn, Soren; Grollier, Julie; Lecerf, Gwendal; ...

2017-04-03

In the brain, learning is achieved through the ability of synapses to reconfigure the strength by which they connect neurons (synaptic plasticity). In promising solid-state synapses called memristors, conductance can be finely tuned by voltage pulses and set to evolve according to a biological learning rule called spike-timing-dependent plasticity (STDP). Future neuromorphic architectures will comprise billions of such nanosynapses, which require a clear understanding of the physical mechanisms responsible for plasticity. Here we report on synapses based on ferroelectric tunnel junctions and show that STDP can be harnessed from inhomogeneous polarization switching. Through combined scanning probe imaging, electrical transport andmore » atomic-scale molecular dynamics, we demonstrate that conductance variations can be modelled by the nucleation-dominated reversal of domains. Finally, based on this physical model, our simulations show that arrays of ferroelectric nanosynapses can autonomously learn to recognize patterns in a predictable way, opening the path towards unsupervised learning in spiking neural networks.« less

Quasiparticle Breakdown and Spin Hamiltonian of the Frustrated Quantum Pyrochlore Yb_{2}Ti_{2}O_{7} in a Magnetic Field.

PubMed

Thompson, J D; McClarty, P A; Prabhakaran, D; Cabrera, I; Guidi, T; Coldea, R

2017-08-04

The frustrated pyrochlore magnet Yb_{2}Ti_{2}O_{7} has the remarkable property that it orders magnetically but has no propagating magnons over wide regions of the Brillouin zone. Here we use inelastic neutron scattering to follow how the spectrum evolves in cubic-axis magnetic fields. At high fields we observe, in addition to dispersive magnons, a two-magnon continuum, which grows in intensity upon reducing the field and overlaps with the one-magnon states at intermediate fields leading to strong renormalization of the dispersion relations, and magnon decays. Using heat capacity measurements we find that the low- and high-field regions are smoothly connected with no sharp phase transition, with the spin gap increasing monotonically in field. Through fits to an extensive data set of dispersion relations combined with magnetization measurements, we reevaluate the spin Hamiltonian, finding dominant quantum exchange terms, which we propose are responsible for the anomalously strong fluctuations and quasiparticle breakdown effects observed at low fields.

GPU accelerated fuzzy connected image segmentation by using CUDA.

PubMed

Zhuge, Ying; Cao, Yong; Miller, Robert W

2009-01-01

Image segmentation techniques using fuzzy connectedness principles have shown their effectiveness in segmenting a variety of objects in several large applications in recent years. However, one problem of these algorithms has been their excessive computational requirements when processing large image datasets. Nowadays commodity graphics hardware provides high parallel computing power. In this paper, we present a parallel fuzzy connected image segmentation algorithm on Nvidia's Compute Unified Device Architecture (CUDA) platform for segmenting large medical image data sets. Our experiments based on three data sets with small, medium, and large data size demonstrate the efficiency of the parallel algorithm, which achieves a speed-up factor of 7.2x, 7.3x, and 14.4x, correspondingly, for the three data sets over the sequential implementation of fuzzy connected image segmentation algorithm on CPU.

Vocational Education and Training and the Therapeutic Turn

ERIC Educational Resources Information Center

Hyland, Terry

2006-01-01

The concept of "therapeutic education" is being increasingly used in contemporary education policy studies to identify learning initiatives which are dominated by objectives linked to personal and social skills, emotional intelligence and building self-esteem. Contemporary educational goals connected with such strategies have been…

Underneath Hypercapitalism

ERIC Educational Resources Information Center

Luke, Allan

2007-01-01

As Joel Spring's (2007/this issue) description of Singapore's Orchard Road suggests, Benetton, Zara, Nike, BMW, LG, and Microsoft dominate the visual and textual landscape where signage, advertising, packaging, labeling, and the environments of the connected underground malls and walkways merge into a wall-to-wall, 24/7 print and visual…

LAND USE AND SEASONAL EFFECTS ON URBAN STORMWATER RUNOFF MICROORGANISM CONCENTRATIONS

EPA Science Inventory

Stormwater samples collected from storm sewers draining small municipal separate storm sewer systems shown to be free of cross connections within an urban watershed dominated by a single land use were analyzed for pathogens (Pseudomonas aeruginosa and Staphylococcus aureus) and i...

Jockeying for Supremacy in a Networked World.

ERIC Educational Resources Information Center

Barry, Jeff; And Others

1996-01-01

Provides an overview of the 1995 automated system marketplace, compiled by analysis of data gathered from 27 vendors. Topics include sales data; dominant vendors in different library sectors; company restructuring and consolidation; plans for technological upgrades, especially Internet connectivity, and improved customer support, service, and…

TRMM-TMI Satellite Observed Soil Moisture and Vegetation Density (1998-2005) Show Strong Connection with El Nino in Eastern Australia

NASA Technical Reports Server (NTRS)

Liu, Yi; van Dijk, Albert I.J.M.; Owe, Manfred

2007-01-01

Spatiotemporal patterns in soil moisture and vegetation water content across mainland Australia were investigated from 1998 through 2005, using TRMMITMI passive microwave observations. The Empirical Orthogonal Function technique was used to extract dominant spatial and temporal patterns in retrieved estimates of moisture content for the top 1-cm of soil (theta) and vegetation moisture content (via optical depth tau). The dominant temporal theta and tau patterns were strongly correlated to El Nino/Southern Oscillation (ENSO) in spring (3 = 0.90), and to a progressively lesser extent autumn, summer and winter. The Indian Ocean Dipole (IOD) index also explained part of the variation in spring 8 and z. Cluster analysis suggested that the regions most affected by ENS0 are mainly located in eastern Australia. The results suggest that the drought conditions experienced in eastern Australia since 2000 an clearly expressed in these satellite observations have a strong connection with ENSO patterns.

Network-wide reorganization of procedural memory during NREM sleep revealed by fMRI

PubMed Central

Vahdat, Shahabeddin; Fogel, Stuart; Benali, Habib; Doyon, Julien

2017-01-01

Sleep is necessary for the optimal consolidation of newly acquired procedural memories. However, the mechanisms by which motor memory traces develop during sleep remain controversial in humans, as this process has been mainly investigated indirectly by comparing pre- and post-sleep conditions. Here, we used functional magnetic resonance imaging and electroencephalography during sleep following motor sequence learning to investigate how newly-formed memory traces evolve dynamically over time. We provide direct evidence for transient reactivation followed by downscaling of functional connectivity in a cortically-dominant pattern formed during learning, as well as gradual reorganization of this representation toward a subcortically-dominant consolidated trace during non-rapid eye movement (NREM) sleep. Importantly, the putamen functional connectivity within the consolidated network during NREM sleep was related to overnight behavioral gains. Our results demonstrate that NREM sleep is necessary for two complementary processes: the restoration and reorganization of newly-learned information during sleep, which underlie human motor memory consolidation. DOI: http://dx.doi.org/10.7554/eLife.24987.001 PMID:28892464

78 FR 67099 - Submission for OMB Review; Comment Request

Federal Register 2010, 2011, 2012, 2013, 2014

2013-11-08

... professionals, who provide meals in institutional settings, can locate processors who manufacture foods... Service Title: USDA Food Connect Web site. OMB Control Number: 0581-0224. Summary of Collection: The USDA Food Connect Web site (previously known as the USDA Food and Commodity Connection Web site) operates...

29 CFR 1910.334 - Use of equipment.

Code of Federal Regulations, 2010 CFR

2010-07-01

.... (a) Portable electric equipment. This paragraph applies to the use of cord- and plug-connected... in a manner which will not cause damage. Flexible electric cords connected to equipment may not be...) Portable cord- and plug-connected equipment and flexible cord sets (extension cords) shall be visually...

10 CFR Appendix H to Subpart B of... - Uniform Test Method for Measuring the Power Consumption of Television Sets

Code of Federal Regulations, 2014 CFR

2014-01-01

... connections (e.g., Wi-Fi and Ethernet), the TV shall be configured and connected to a single network source in... Hierarchy Priority Network connection type 1 Wi-Fi (Institution of Electrical and Electronics Engineers—IEEE...

Does the Shanghai-Hong Kong Stock Connect significantly affect the A-H premium of the stocks?

NASA Astrophysics Data System (ADS)

Hui, Eddie C. M.; Chan, Ka Kwan Kevin

2018-02-01

Since the Shanghai-Hong Kong Stock Connect ("the Connect") was launched in late 2014, more and more Mainland investors have invested in Hong Kong listed shares, and vice versa, increasing the transaction volume of the stock market on both sides. However, only a few studies investigated how the Shanghai-Hong Kong Stock Connect affected the pricing dynamics of stocks listed in both Shanghai and Hong Kong. Applying linear regression, this study investigates how the Connect affects the H-share discounts of 12 stocks cross-listed in Shanghai and Hong Kong. A new feature of our model is that we add a dummy variable so as to be the first study to examine the effect of the China financial crisis on the A-H premium of the stocks. We find that the A-H premium of all stocks widens significantly after the Connect is launched, implying immatureness or even inefficiency of China's financial market. Furthermore, the result shows that trading activities in the mainland market affects the A-H premium more significantly than trading activities in the Hong Kong market do. This implies that China's financial market plays a dominant role in the Connect.

Facilitating Neuronal Connectivity Analysis of Evoked Responses by Exposing Local Activity with Principal Component Analysis Preprocessing: Simulation of Evoked MEG

PubMed Central

Gao, Lin; Zhang, Tongsheng; Wang, Jue; Stephen, Julia

2014-01-01

When connectivity analysis is carried out for event related EEG and MEG, the presence of strong spatial correlations from spontaneous activity in background may mask the local neuronal evoked activity and lead to spurious connections. In this paper, we hypothesized PCA decomposition could be used to diminish the background activity and further improve the performance of connectivity analysis in event related experiments. The idea was tested using simulation, where we found that for the 306-channel Elekta Neuromag system, the first 4 PCs represent the dominant background activity, and the source connectivity pattern after preprocessing is consistent with the true connectivity pattern designed in the simulation. Improving signal to noise of the evoked responses by discarding the first few PCs demonstrates increased coherences at major physiological frequency bands when removing the first few PCs. Furthermore, the evoked information was maintained after PCA preprocessing. In conclusion, it is demonstrated that the first few PCs represent background activity, and PCA decomposition can be employed to remove it to expose the evoked activity for the channels under investigation. Therefore, PCA can be applied as a preprocessing approach to improve neuronal connectivity analysis for event related data. PMID:22918837

Facilitating neuronal connectivity analysis of evoked responses by exposing local activity with principal component analysis preprocessing: simulation of evoked MEG.

PubMed

Gao, Lin; Zhang, Tongsheng; Wang, Jue; Stephen, Julia

2013-04-01

When connectivity analysis is carried out for event related EEG and MEG, the presence of strong spatial correlations from spontaneous activity in background may mask the local neuronal evoked activity and lead to spurious connections. In this paper, we hypothesized PCA decomposition could be used to diminish the background activity and further improve the performance of connectivity analysis in event related experiments. The idea was tested using simulation, where we found that for the 306-channel Elekta Neuromag system, the first 4 PCs represent the dominant background activity, and the source connectivity pattern after preprocessing is consistent with the true connectivity pattern designed in the simulation. Improving signal to noise of the evoked responses by discarding the first few PCs demonstrates increased coherences at major physiological frequency bands when removing the first few PCs. Furthermore, the evoked information was maintained after PCA preprocessing. In conclusion, it is demonstrated that the first few PCs represent background activity, and PCA decomposition can be employed to remove it to expose the evoked activity for the channels under investigation. Therefore, PCA can be applied as a preprocessing approach to improve neuronal connectivity analysis for event related data.

An Index of Longitudinal Hydrologic Connectivity to Evaluate Effects of Water Abstraction on Streams Dominated by Migratory Shrimps

NASA Astrophysics Data System (ADS)

Crook, K. E.; Pringle, C. M.; Freeman, M. C.; Scatena, F. N.

2005-05-01

Massive water withdrawals from streams draining the Caribbean National Forest (CNF), Puerto Rico, are threatening their biotic integrity. Migratory tropical shrimps are ideal indicator species to measure water withdrawal effects on riverine connectivity and biointegrity because: (1) their migratory range encompasses the stream network from estuaries to headwater streams; (2) they represent greater than 90% of biomass in streams draining the CNF; and (3) they facilitate important in-stream ecological processes. We developed an index to evaluate individual and cumulative effects of water intakes on each stage of the shrimp's life-cycle. Effect of water withdrawal on longitudinal connectivity was evaluated by combining effects of water withdrawal on larval and juvenile shrimps. Larvae require downstream transport to the estuary for advancement to the next life-stage, and juveniles similarly require access to headwater streams. Therefore, these two life-stages represent the bi-directional connectivity of streams from headwaters to estuaries. Seventeen water intakes were evaluated in and around the CNF. Larger intakes cause a greater decrease in connectivity than smaller intakes; however, several small, high elevation intakes had very low connectivity. Also, intakes with alternative designs, such as a French drain, have reduced effects on connectivity.

Successful Object Encoding Induces Increased Directed Connectivity in Presymptomatic Early-Onset Alzheimer’s Disease

PubMed Central

Ochoa, John Fredy; Alonso, Joan Francesc; Duque, Jon Edinson; Tobón, Carlos Andrés; Mañanas, Miguel Angel; Lopera, Francisco; Hernández, Alher Mauricio

2016-01-01

Background: Recent studies report increases in neural activity in brain regions critical to episodic memory at preclinical stages of Alzheimer’s disease (AD). Although electroencephalography (EEG) is widely used in AD studies, given its non-invasiveness and low cost, there is a need to translate the findings in other neuroimaging methods to EEG. Objective: To examine how the previous findings using functional magnetic resonance imaging (fMRI) at preclinical stage in presenilin-1 E280A mutation carriers could be assessed and extended, using EEG and a connectivity approach. Methods: EEG signals were acquired during resting and encoding in 30 normal cognitive young subjects, from an autosomal dominant early-onset AD kindred from Antioquia, Colombia. Regions of the brain previously reported as hyperactive were used for connectivity analysis. Results: Mutation carriers exhibited increasing connectivity at analyzed regions. Among them, the right precuneus exhibited the highest changes in connectivity. Conclusion: Increased connectivity in hyperactive cerebral regions is seen in individuals, genetically-determined to develop AD, at preclinical stage. The use of a connectivity approach and a widely available neuroimaging technique opens the possibility to increase the use of EEG in early detection of preclinical AD. PMID:27792014

Achieving climate connectivity in a fragmented landscape

PubMed Central

Lawler, Joshua J.; McRae, Brad H.; Nuñez, Tristan A.; Theobald, David M.

2016-01-01

The contiguous United States contains a disconnected patchwork of natural lands. This fragmentation by human activities limits species’ ability to track suitable climates as they rapidly shift. However, most models that project species movement needs have not examined where fragmentation will limit those movements. Here, we quantify climate connectivity, the capacity of landscape configuration to allow species movement in the face of dynamically shifting climate. Using this metric, we assess to what extent habitat fragmentation will limit species movements in response to climate change. We then evaluate how creating corridors to promote climate connectivity could potentially mitigate these restrictions, and we assess where strategies to increase connectivity will be most beneficial. By analyzing fragmentation patterns across the contiguous United States, we demonstrate that only 41% of natural land area retains enough connectivity to allow plants and animals to maintain climatic parity as the climate warms. In the eastern United States, less than 2% of natural area is sufficiently connected. Introducing corridors to facilitate movement through human-dominated regions increases the percentage of climatically connected natural area to 65%, with the most impactful gains in low-elevation regions, particularly in the southeastern United States. These climate connectivity analyses allow ecologists and conservation practitioners to determine the most effective regions for increasing connectivity. More importantly, our findings demonstrate that increasing climate connectivity is critical for allowing species to track rapidly changing climates, reconfiguring habitats to promote access to suitable climates. PMID:27298349

Achieving climate connectivity in a fragmented landscape.

PubMed

McGuire, Jenny L; Lawler, Joshua J; McRae, Brad H; Nuñez, Tristan A; Theobald, David M

2016-06-28

The contiguous United States contains a disconnected patchwork of natural lands. This fragmentation by human activities limits species' ability to track suitable climates as they rapidly shift. However, most models that project species movement needs have not examined where fragmentation will limit those movements. Here, we quantify climate connectivity, the capacity of landscape configuration to allow species movement in the face of dynamically shifting climate. Using this metric, we assess to what extent habitat fragmentation will limit species movements in response to climate change. We then evaluate how creating corridors to promote climate connectivity could potentially mitigate these restrictions, and we assess where strategies to increase connectivity will be most beneficial. By analyzing fragmentation patterns across the contiguous United States, we demonstrate that only 41% of natural land area retains enough connectivity to allow plants and animals to maintain climatic parity as the climate warms. In the eastern United States, less than 2% of natural area is sufficiently connected. Introducing corridors to facilitate movement through human-dominated regions increases the percentage of climatically connected natural area to 65%, with the most impactful gains in low-elevation regions, particularly in the southeastern United States. These climate connectivity analyses allow ecologists and conservation practitioners to determine the most effective regions for increasing connectivity. More importantly, our findings demonstrate that increasing climate connectivity is critical for allowing species to track rapidly changing climates, reconfiguring habitats to promote access to suitable climates.

Disrupted directed connectivity along the cingulate cortex determines vigilance after sleep deprivation

PubMed Central

Piantoni, Giovanni; Cheung, Bing Leung P.; Van Veen, Barry D.; Romeijn, Nico; Riedner, Brady A.; Tononi, Giulio; Van Der Werf, Ysbrand D.; Van Someren, Eus J.W.

2013-01-01

The cingulate cortex is regarded as the backbone of structural and functional connectivity of the brain. While its functional connectivity has been intensively studied, little is known about its effective connectivity, its modulation by behavioral states, and its involvement in cognitive performance. Given their previously reported effects on cingulate functional connectivity, we investigated how eye-closure and sleep deprivation changed cingulate effective connectivity, estimated from resting-state high-density electroencephalography (EEG) using a novel method to calculate Granger Causality directly in source space. Effective connectivity along the cingulate cortex was dominant in the forward direction. Eyes-open connectivity in the forward direction was greater compared to eyes-closed, in well-rested participants. The difference between eyes-open and eyes-closed connectivity was attenuated and no longer significant after sleep deprivation. Individual variability in the forward connectivity after sleep deprivation predicted subsequent task performance, such that those subjects who showed a greater increase in forward connectivity between the eyes-open and the eyes-closed periods also performed better on a sustained attention task. Effective connectivity in the opposite, backward, direction was not affected by whether the eyes were open or closed or by sleep deprivation. These findings indicate that the effective connectivity from posterior to anterior cingulate regions is enhanced when a well-rested subject has his eyes open compared to when they are closed. Sleep deprivation impairs this directed information flow, proportional to its deleterious effect on vigilance. Therefore, sleep may play a role in the maintenance of waking effective connectivity. PMID:23643925

A Molecular Connection Between Cancer Proliferation and Metastasis Mediated by Akt Kinase

DTIC Science & Technology

2006-08-01

promoter. We set out to further map the molecular connections between Akt kinase activity and osteopontin transcription in breast epithelial cells. For...Because different growth rates did not account for the distinct phenotypes generated by osteopontin-a and osteopontin-c in soft agar, we set out ...murine encephalomyelitis virus, reovirus, Mycoplasma pulmonis, mouse parvovirus , epizootic diarrhea of infant mice virus, lymphocytic choriomeningitis

The Chess and Mathematics Connection: More than Just a Game

ERIC Educational Resources Information Center

Berkman, Robert M.

2004-01-01

This article describes connections between chess and mathematics, including examples of activities that connect chess with set theory, patterns, algebra, geometry, combinatorics, and Pascal's triangle. The author observes that competitive games play a dual purpose in advancing the work of mathematics educators: to reinforce a specific skill and to…

School Connectedness for Students in Low-Income Urban High Schools

ERIC Educational Resources Information Center

Nasir, Na'ilah Suad; Jones, Amina; McLaughlin, Milbrey Wallin

2011-01-01

Background/Context: In this article, we explore school connectedness for students in a high-poverty urban school. Current approaches to measuring connection conflate behavior and attitudinal measures of connection and rarely explore school connection in urban school settings. Purpose/Objective/Research Question/Focus of Study: We examine…

The Effect of Parkinson Disease Tremor Phenotype on Cepstral Peak Prominence and Transglottal Airflow in Vowels and Speech.

PubMed

Burk, Brittany R; Watts, Christopher R

2018-02-19

The physiological manifestations of Parkinson disease are heterogeneous, as evidenced by disease subtypes. Dysphonia has been well documented as an early and progressively significant impairment associated with the disease. The purpose of this study was to investigate how acoustic and aerodynamic measures of vocal function were affected by Parkinson tremor subtype (phenotype) in an effort to better understand the heterogeneity of voice impairment severity in Parkinson disease. This is a prospective case-control study. Thirty-two speakers with Parkinson disease assigned to tremor and nontremor phenotypes and 10 healthy controls were recruited. Sustained vowels and connected speech were recorded from each speaker. Acoustic measures of cepstral peak prominence (CPP) and aerodynamic measures of transglottal airflow (TAF) were calculated from the recorded acoustic and aerodynamic waveforms. Speakers with a nontremor dominant phenotype exhibited significantly (P < 0.05) lower CPP and higher TAF in vowels compared with the tremor dominant phenotype and control speakers, who were not different from each other. No significant group differences were observed for CPP or TAF in connected speech. When producing vowels, participants with nontremor dominant phenotype exhibited reduced phonation periodicity and elevated TAF compared with tremor dominant and control participants. This finding is consistent with differential limb-motor and cognitive impairments between tremor and nontremor phenotypes reported in the extant literature. Results suggest that sustained vowel production may be sensitive to phonatory control as a function of Parkinson tremor phenotype in mild to moderate stages of the disease. Copyright © 2018 The Voice Foundation. Published by Elsevier Inc. All rights reserved.

Where Are the Faculty?

ERIC Educational Resources Information Center

Hoskins, Barbara J.

2010-01-01

This article discusses how faculty members feel about the growth and quality of distance, distributed, and online higher education. The twenty-first century university must innovate to survive as the Internet becomes the dominant source of knowledge and learning. The twenty-first century student connects with information differently than earlier…

Family, Environment, and Value Questions in Today's World.

ERIC Educational Resources Information Center

Engberg, Lila E.

1989-01-01

Discusses how the values of the larger society are reflected in life-styles of families and individual decisions. Questions the cause and effect connection of dominant value systems, economy, and policy as being appropriate and relevant to an environmentally healthy symbiosis between man and the ecosystem. (Author)

Ranking Specific Sets of Objects.

PubMed

Maly, Jan; Woltran, Stefan

2017-01-01

Ranking sets of objects based on an order between the single elements has been thoroughly studied in the literature. In particular, it has been shown that it is in general impossible to find a total ranking - jointly satisfying properties as dominance and independence - on the whole power set of objects. However, in many applications certain elements from the entire power set might not be required and can be neglected in the ranking process. For instance, certain sets might be ruled out due to hard constraints or are not satisfying some background theory. In this paper, we treat the computational problem whether an order on a given subset of the power set of elements satisfying different variants of dominance and independence can be found, given a ranking on the elements. We show that this problem is tractable for partial rankings and NP-complete for total rankings.

Generalized minimum dominating set and application in automatic text summarization

NASA Astrophysics Data System (ADS)

Xu, Yi-Zhi; Zhou, Hai-Jun

2016-03-01

For a graph formed by vertices and weighted edges, a generalized minimum dominating set (MDS) is a vertex set of smallest cardinality such that the summed weight of edges from each outside vertex to vertices in this set is equal to or larger than certain threshold value. This generalized MDS problem reduces to the conventional MDS problem in the limiting case of all the edge weights being equal to the threshold value. We treat the generalized MDS problem in the present paper by a replica-symmetric spin glass theory and derive a set of belief-propagation equations. As a practical application we consider the problem of extracting a set of sentences that best summarize a given input text document. We carry out a preliminary test of the statistical physics-inspired method to this automatic text summarization problem.

Small scale morphodynamics of shoreface-connected ridges and their impact on benthic macrofauna

NASA Astrophysics Data System (ADS)

Markert, Edith; Kröncke, Ingrid; Kubicki, Adam

2015-05-01

The first interdisciplinary analysis (biological and sedimentological) of macrofauna communities influenced by long-term morphodynamics of shoreface-connected ridges in the German Bight on a small scale is presented in this study. The study area covering 4 km2 was located off the island of Spiekeroog, in an area known as a Tellina fabula community. Sediment samples taken at 27 sample sites were coupled with side-scan sonar data to draw a precise sediment map of the area, as well as with high-resolution multi-beam bathymetry data to understand the morphodynamic changes of the seabed between 2003 and 2010. The macrofauna data acquired at the same 27 sites were analysed for community structure using non-metric multidimensional scaling, the ANOSIM and PERMANOVA tests. Correlations between biological and environmental variables were examined with the BIOENV procedure. The study revealed a shore-parallel sediment zonation with clear and sharp borders induced by local morphodynamics, which together with specific local bathymetry affected the formation of three different macrofauna affinity groups. One group was located on the shoreface and in the troughs (dominant species: Scoloplos armiger, Lanice conchilega, Notomastus latericeus), one on the landward flanks of the ridges (dominant species: Aonides paucibranchiata, Goniadella bobretzkii), and one on the ridge crests (dominant species: Ophelia spp. juv., Spio goniocephala). The spatial distribution of the affinity groups, their taxa number and abundance of species was dependent on a surface sediment pattern resulting from local hydrodynamics, which in turn is known to influence the food availability. A seaward steepening of ridges took place and was an effect of erosion up to 0.34 m on landward flanks in and accumulation up to 0.29 m on seaward flanks in seven years. The studied shoreface-connected ridges migrated seawards with a pace of 5 m/year for the large ridge and 20 m/year for the small ridge. Elongated mud-pockets were common in the deepest parts of the troughs, but seemed to be unstable in time. The identified general seaward migration of shoreface-connected ridges seemed to be slow enough for the macrofauna communities to migrate with the morphodynamics of the ridges.

Enterprise Dominance as Related to Communication and Farmers' Technological Competence and Satisfaction.

ERIC Educational Resources Information Center

Coughenour, C. M.

An investigation was conducted to assess the effect of enterprise dominance on selected aspects of the infrastructure of agriculture. The hypothesis was that dominance of a particular type of farming in an area is signified by a set of cultural and social values that dispose the agencies serving farmers and the farmers themselves to favor…

Wetland Hydrologic Connectivity to Downstream Waters: A Classification Approach and National Assessment

NASA Astrophysics Data System (ADS)

Leibowitz, S. G.; Hill, R. A.; Weber, M.; Jones, C., Jr.; Rains, M. C.; Creed, I. F.; Christensen, J.

2017-12-01

Connectivity has become a major focus of hydrological and ecological studies. Connectivity enhances fluxes among landscape features, whereas isolation eliminates or reduces such flows. Thus connectivity can be an important characteristic controlling ecosystem services. Hydrologic connectivity is particularly significant, since chemical and biological flows are often associated with water movement. Wetlands have many important functions, and the degree to which they are hydrologically connected influences the effect they have on downstream waters. Wetlands with high connectivity can serve as sources (e.g., net exporters of dissolved organic carbon), while those with low connectivity can function as sinks (e.g., net importers of suspended sediments). We developed a system to classify wetlands based on type, magnitude, and frequency of hydrologic connectivity with downstream waters. We determined type (riparian, non-riparian surface, and non-riparian subsurface) by considering soil and bedrock permeability. For magnitude, we developed indices to represent travel time based on Manning's kinematic and Darcy's equations. We used soil drainage class as an indicator of frequency. We also included an index that assesses relative level of anthropogenic impacts to connectivity (e.g., presence of canals and ditches and impervious surfaces). The classification system was designed to be applied at various spatial scales using available data. The system was applied to 4.7 million wetlands in the conterminous United States, using the National Land Cover Dataset and other nationally available geospatial data, and the resulting maps were assessed for patterns in wetland connectivity. While wetland connectivity was dominated by fast, frequent riparian connections nationally, distributions of connectivity were characteristic for each region. Consideration of these distributions of connectivity should promote better management of watershed functions such as flood control and water quality improvement.

Fuel-cell based power generating system having power conditioning apparatus

DOEpatents

Mazumder, Sudip K.; Pradhan, Sanjaya K.

2010-10-05

A power conditioner includes power converters for supplying power to a load, a set of selection switches corresponding to the power converters for selectively connecting the fuel-cell stack to the power converters, and another set of selection switches corresponding to the power converters for selectively connecting the battery to the power converters. The power conveners output combined power that substantially optimally meets a present demand of the load.

Foundational model of structural connectivity in the nervous system with a schema for wiring diagrams, connectome, and basic plan architecture

PubMed Central

Swanson, Larry W.; Bota, Mihail

2010-01-01

The nervous system is a biological computer integrating the body's reflex and voluntary environmental interactions (behavior) with a relatively constant internal state (homeostasis)—promoting survival of the individual and species. The wiring diagram of the nervous system's structural connectivity provides an obligatory foundational model for understanding functional localization at molecular, cellular, systems, and behavioral organization levels. This paper provides a high-level, downwardly extendible, conceptual framework—like a compass and map—for describing and exploring in neuroinformatics systems (such as our Brain Architecture Knowledge Management System) the structural architecture of the nervous system's basic wiring diagram. For this, the Foundational Model of Connectivity's universe of discourse is the structural architecture of nervous system connectivity in all animals at all resolutions, and the model includes two key elements—a set of basic principles and an internally consistent set of concepts (defined vocabulary of standard terms)—arranged in an explicitly defined schema (set of relationships between concepts) allowing automatic inferences. In addition, rules and procedures for creating and modifying the foundational model are considered. Controlled vocabularies with broad community support typically are managed by standing committees of experts that create and refine boundary conditions, and a set of rules that are available on the Web. PMID:21078980

"The Thing about Work": Gendered Narratives of a Transnational, Trilingual Mexicano

ERIC Educational Resources Information Center

Menard-Warwick, Julia

2006-01-01

Through narratives taken from life history interviews with an indigenous Mexican male immigrant in California, this paper examines the connection between masculinities and the learning of dominant languages associated with access to economic opportunities. In portraying the teller's engagements with work and education in both countries, these life…

Crack in the Foundation Defense Transformation and the Underlying Assumption of Dominant Knowledge in Future War

DTIC Science & Technology

2003-04-07

network-centric warfare, however, emboldened by the booming economy, displayed irrational exuberance in connection with the degree of certainty that...education. In addition to creating an imbalance of forces and impeding joint integration, the irrational faith in certainty threatens to waste

A Connected Space for Early Experiential Learning in Teacher Education

ERIC Educational Resources Information Center

Yu, Yong; Hunt, Jean Ann

2016-01-01

Carefully constructed field-based experiences in teacher education programs have been recognized as one of the essential conditions for effective teacher learning. Most college/university-based teacher education programs, however, are still dominated by the epistemology that academic knowledge is the authoritative source of knowledge about…

Ecohydrological processes and ecosystem services in the Anthropocene: a review

Treesearch

Ge Sun; Dennis Hallema; Heidi Asbjornsen

2017-01-01

The framework for ecosystem services has been increasingly used in integrated watershed ecosystem management practices that involve scientists, engineers, managers, and policy makers. The objective of this review is to explore the intimate connections between ecohydrological processes and water-related ecosystem services in human-dominated ecosystems in the...

Assessment of bone mineral status in children with Marfan syndrome

USDA-ARS?s Scientific Manuscript database

Marfan syndrome (MFS) is an autosomal dominant connective tissue disorder with skeletal involvement. It is caused by mutations in fibrillin1 (FBN1) gene resulting in activation of TGF-ßeta, which developmentally regulates bone mass and matrix properties. There is no consensus regarding bone minerali...

Profiles of an Acquisition Generation: Nontraditional Heritage Speakers of Spanish

ERIC Educational Resources Information Center

DeFeo, Dayna Jean

2018-01-01

Though definitions vary, the literature on heritage speakers of Spanish identifies two primary attributes: a linguistic and cultural connection to the language. This article profiles four Anglo college students who grew up in bilingual or Spanish-dominant communities in the Southwest who self-identified as Spanish heritage speakers, citing…

Presidential Elections in the Age of Television.

ERIC Educational Resources Information Center

Rothwell, Jennifer Truran

2000-01-01

Explores the role of television in politics providing historical examples of the use of television and its possible effects on elections. Focuses on television as the dominant medium for politics, the connections among television, advertising, and political money, and ideas for reforming the electoral process. Includes a teaching activity on…

Sex Segregation and Salary Structure in Academia.

ERIC Educational Resources Information Center

Fox, Mary Frank

1981-01-01

Do high proportions of women depress men's salary levels in academic departments? Are women's salary levels higher in male-dominated departments? Are men salary-compensated for working with women? This study demonstrated instead that the sex-salary relationship rests upon the connection between department composition and sex-related achievement…

Late Departures from Paper-Based to Supported Networked Learning in South Africa: Lessons Learned

ERIC Educational Resources Information Center

Kok, Illasha; Beter, Petra; Esterhuizen, Hennie

2018-01-01

Fragmented connectivity in South Africa is the dominant barrier for digitising initiatives. New insights surfaced when a university-based nursing programme introduced tablets within a supportive network learning environment. A qualitative, explorative design investigated adult nurses' experiences of the realities when moving from paper-based…

Re-Framing Student Academic Freedom: A Capability Perspective

ERIC Educational Resources Information Center

Macfarlane, Bruce

2012-01-01

The scholarly debate about academic freedom focuses almost exclusively on the rights of academic faculty. Student academic freedom is rarely discussed and is normally confined to debates connected with the politicisation of the curriculum. Concerns about (student) freedom of speech reflect the dominant role of negative rights in the analysis of…

Deployable geodesic truss structure

NASA Technical Reports Server (NTRS)

Mikulas, Martin M., Jr. (Inventor); Rhodes, Marvin D. (Inventor); Simonton, J. Wayne (Inventor)

1987-01-01

A deployable geodesic truss structure which can be deployed from a stowed state to an erected state is described. The truss structure includes a series of bays, each bay having sets of battens connected by longitudinal cross members which give the bay its axial and torsional stiffness. The cross members are hinged at their mid point by a joint so that the cross members are foldable for deployment or collapsing. The bays are deployed and stabilized by actuator means connected between the mid point joints of the cross members. Hinged longerons may be provided to also connect the sets of battens and to collapse for stowing with the rest of the truss structure.

Representations of mechanical assembly sequences

NASA Technical Reports Server (NTRS)

Homem De Mello, Luiz S.; Sanderson, Arthur C.

1991-01-01

Five types of representations for assembly sequences are reviewed: the directed graph of feasible assembly sequences, the AND/OR graph of feasible assembly sequences, the set of establishment conditions, and two types of sets of precedence relationships. (precedence relationships between the establishment of one connection between parts and the establishment of another connection, and precedence relationships between the establishment of one connection and states of the assembly process). The mappings of one representation into the others are established. The correctness and completeness of these representations are established. The results presented are needed in the proof of correctness and completeness of algorithms for the generation of mechanical assembly sequences.

46 CFR 525.3 - Availability of marine terminal operator schedules.

Code of Federal Regulations, 2010 CFR

2010-10-01

...) Availability of terminal schedules—(1) Availability to the Commission. A complete and current set of terminal... computer (PC) by: (1) Dial-up connection via public switched telephone networks (PSTN); or (2) The Internet (Web) by: (i) Web browser; or (ii) Telnet session. (c) Dial-up connection via PSTN. (1) This connection...

46 CFR 525.3 - Availability of marine terminal operator schedules.

Code of Federal Regulations, 2011 CFR

2011-10-01

...) Availability of terminal schedules—(1) Availability to the Commission. A complete and current set of terminal... computer (PC) by: (1) Dial-up connection via public switched telephone networks (PSTN); or (2) The Internet (Web) by: (i) Web browser; or (ii) Telnet session. (c) Dial-up connection via PSTN. (1) This connection...

A dc to dc converter

NASA Astrophysics Data System (ADS)

Willis, A. E.; Gould, J. M.; Matheney, J. L.; Garrett, H.

1984-01-01

The object of the invention is to provide an improved converter for converting one direct current voltage to another. A plurality of phased square wave voltages are provided from a ring counter through amplifiers to a like plurality of output transformers. Each of these transformers has two windings, and S(1) winding and an S(2) winding. The S(1) windings are connected in series, then the S(2) windings are connected in series, and finally, the two sets of windings are connected in series. One of six SCRs is connected between each two series connected windings to a positive output terminal and one of diodes is connected between each set of two windings of a zero output terminal. By virtue of this configuration, a quite high average direct current voltage is obtained, which varies between full voltage and two-thirds full voltage rather than from full voltage to zero. Further, its variation, ripple frequency, is reduced to one-sixth of that present in a single phase system. Application to raising battery voltage for an ion propulsion system is mentioned.

[Prevention of stress in the workplace].

PubMed

Vaccani, R

2009-01-01

The chronological/logical path goes from the base distinction that classify the stressing phenomena between the two categories, eu-stress and dis-stress. It is underlined the subjective characteristic of stressing processes, the statement that what might be eu-stress for someone can be dis-stress for others. The organizational setting can be considered as a privileged preventive intervention area. Therefore it is suggested this categorization for the stress organizational causes: Causes connected to the organizational system (Incoherencies or structural understaffing, procedural incoherencies); Causes connected to the wrong alignment of competencies; Causes connected to the wrong alignment of aptitudes; Causes connected to the social dynamics of abuse of power. The categories to differentiate the stress organizational causes are proposed to give a useful glossary to design various preventive actions: Preventive actions on the organizational setting; Preventive actions through education; Preventive actions about role redesign; Preventive actions aimed at sustaining ethical social cohabitation. Finally, it is assessed that the approach to organizational stress requires an holistic, multi disciplinary perspective analysis, able to connect the ethic and qualitative characteristic of the markets (closed and open markets) to the organizational setting, to the subject peculiar character at work and its impact with working roles, to the social dynamics derived from hierarchical roles, to the organizational moods, to the individual perceptions, to the clinical paths.

Simultaneous Occurrence of Duane Retraction Syndrome with Marfan Syndrome

PubMed Central

Kothari, Mihir; Manurung, Florence; Mithiya, Bhavesh

2011-01-01

Marfan syndrome (MFS) is an autosomal dominant disorder of connective tissue, while Duane retraction syndrome (DRS) is a congenital cranial dysinnervation disorder (CCDD) which can be transmitted as autosomal dominant disorder in 5–10% of patients. In this paper, we present an 8-year-old girl who presented with left eye DRS and bilateral subluxation of the lens associated with MFS in absence of familial involvement. To our knowledge this is the first case report of DRS with MFS. The occurrence of these syndromes together is very rare and appears to be coincidental. PMID:22606474

45 CFR 146.101 - Basis and scope.

Code of Federal Regulations, 2011 CFR

2011-10-01

... stays in connection with childbirth. Sections 2791 and 2792 of the PHS Act define terms used in the... connection with childbirth. It also sets forth the regulations governing parity between medical/surgical...

45 CFR 146.101 - Basis and scope.

Code of Federal Regulations, 2013 CFR

2013-10-01

... stays in connection with childbirth. Sections 2791 and 2792 of the PHS Act define terms used in the... connection with childbirth. It also sets forth the regulations governing parity between medical/surgical...

45 CFR 146.101 - Basis and scope.

Code of Federal Regulations, 2012 CFR

2012-10-01

... stays in connection with childbirth. Sections 2791 and 2792 of the PHS Act define terms used in the... connection with childbirth. It also sets forth the regulations governing parity between medical/surgical...

Evaluating Landscape Connectivity for Puma concolor and Panthera onca Among Atlantic Forest Protected Areas

NASA Astrophysics Data System (ADS)

Castilho, Camila S.; Hackbart, Vivian C. S.; Pivello, Vânia R.; dos Santos, Rozely F.

2015-06-01

Strictly Protected Areas and riparian forests in Brazil are rarely large enough or connected enough to maintain viable populations of carnivores and animal movement over time, but these characteristics are fundamental for species conservation as they prevent the extinction of isolated animal populations. Therefore, the need to maintain connectivity for these species in human-dominated Atlantic landscapes is critical. In this study, we evaluated the landscape connectivity for large carnivores (cougar and jaguar) among the Strictly Protected Areas in the Atlantic Forest, evaluated the efficiency of the Mosaics of Protected Areas linked to land uses in promoting landscape connectivity, identified the critical habitat connections, and predicted the landscape connectivity status under the implementation of legislation for protecting riparian forests. The method was based on expert opinion translated into land use and land cover maps. The results show that the Protected Areas are still connected by a narrow band of landscape that is permeable to both species and that the Mosaics of Protected Areas increase the amount of protected area but fail to increase the connectivity between the forested mountain ranges (Serra do Mar and Serra da Mantiqueira). Riparian forests greatly increase connectivity, more than tripling the cougars' priority areas. We note that the selection of Brazilian protected areas still fails to create connectivity among the legally protected forest remnants. We recommend the immediate protection of the priority areas identified that would increase the structural landscape connectivity for these large carnivores, especially paths in the SE/NW direction between the two mountain ranges.

Evaluating Landscape Connectivity for Puma concolor and Panthera onca Among Atlantic Forest Protected Areas.

PubMed

Castilho, Camila S; Hackbart, Vivian C S; Pivello, Vânia R; dos Santos, Rozely F

2015-06-01

Strictly Protected Areas and riparian forests in Brazil are rarely large enough or connected enough to maintain viable populations of carnivores and animal movement over time, but these characteristics are fundamental for species conservation as they prevent the extinction of isolated animal populations. Therefore, the need to maintain connectivity for these species in human-dominated Atlantic landscapes is critical. In this study, we evaluated the landscape connectivity for large carnivores (cougar and jaguar) among the Strictly Protected Areas in the Atlantic Forest, evaluated the efficiency of the Mosaics of Protected Areas linked to land uses in promoting landscape connectivity, identified the critical habitat connections, and predicted the landscape connectivity status under the implementation of legislation for protecting riparian forests. The method was based on expert opinion translated into land use and land cover maps. The results show that the Protected Areas are still connected by a narrow band of landscape that is permeable to both species and that the Mosaics of Protected Areas increase the amount of protected area but fail to increase the connectivity between the forested mountain ranges (Serra do Mar and Serra da Mantiqueira). Riparian forests greatly increase connectivity, more than tripling the cougars' priority areas. We note that the selection of Brazilian protected areas still fails to create connectivity among the legally protected forest remnants. We recommend the immediate protection of the priority areas identified that would increase the structural landscape connectivity for these large carnivores, especially paths in the SE/NW direction between the two mountain ranges.

Symmetry of interactions rules in incompletely connected random replicator ecosystems.

PubMed

Kärenlampi, Petri P

2014-06-01

The evolution of an incompletely connected system of species with speciation and extinction is investigated in terms of random replicators. It is found that evolving random replicator systems with speciation do become large and complex, depending on speciation parameters. Antisymmetric interactions result in large systems, whereas systems with symmetric interactions remain small. A co-dominating feature is within-species interaction pressure: large within-species interaction increases species diversity. Average fitness evolves in all systems, however symmetry and connectivity evolve in small systems only. Newcomers get extinct almost immediately in symmetric systems. The distribution in species lifetimes is determined for antisymmetric systems. The replicator systems investigated do not show any sign of self-organized criticality. The generalized Lotka-Volterra system is shown to be a tedious way of implementing the replicator system.

45 CFR 146.101 - Basis and scope.

Code of Federal Regulations, 2014 CFR

2014-10-01

... stays in connection with childbirth. Sections 2791 and 2792 of the PHS Act define terms used in the... to coverage for hospital stays in connection with childbirth. It also sets forth the regulations...

Connected components of irreducible maps and 1D quantum phases

DOE Office of Scientific and Technical Information (OSTI.GOV)

Szehr, Oleg, E-mail: oleg.szehr@posteo.de; Wolf, Michael M., E-mail: wolf@ma.tum.de

We investigate elementary topological properties of sets of completely positive (CP) maps that arise in quantum Perron-Frobenius theory. We prove that the set of primitive CP maps of fixed Kraus rank is path-connected and we provide a complete classification of the connected components of irreducible CP maps at given Kraus rank and fixed peripheral spectrum in terms of a multiplicity index. These findings are then applied to analyse 1D quantum phases by studying equivalence classes of translational invariant matrix product states that correspond to the connected components of the respective CP maps. Our results extend the previously obtained picture inmore » that they do not require blocking of physical sites, they lead to analytic paths, and they allow us to decompose into ergodic components and to study the breaking of translational symmetry.« less

BAMS2 Workspace: a comprehensive and versatile neuroinformatic platform for collating and processing neuroanatomical connections

PubMed Central

Bota, Mihail; Talpalaru, Ştefan; Hintiryan, Houri; Dong, Hong-Wei; Swanson, Larry W.

2014-01-01

We present in this paper a novel neuroinformatic platform, the BAMS2 Workspace (http://brancusi1.usc.edu), designed for storing and processing information about gray matter region axonal connections. This de novo constructed module allows registered users to directly collate their data by using a simple and versatile visual interface. It also allows construction and analysis of sets of connections associated with gray matter region nomenclatures from any designated species. The Workspace includes a set of tools allowing the display of data in matrix and networks formats, and the uploading of processed information in visual, PDF, CSV, and Excel formats. Finally, the Workspace can be accessed anonymously by third party systems to create individualized connectivity networks. All features of the BAMS2 Workspace are described in detail, and are demonstrated with connectivity reports collated in BAMS and associated with the rat sensory-motor cortex, medial frontal cortex, and amygdalar regions. PMID:24668342

Computational analysis of complex systems: Applications to population dynamics and networks

NASA Astrophysics Data System (ADS)

Molnar, Ferenc

In most complex evolving systems, we can often find a critical subset of the constituents that can initiate a global change in the entire system. For example, in complex networks, a critical subset of nodes can efficiently spread information, influence, or control dynamical processes over the entire network. Similarly, in nonlinear dynamics, we can locate key variables, or find the necessary parameters, to reach the attraction basin of a desired global state. In both cases, a fundamental goal is finding the ability to efficiently control these systems. We study two distinct complex systems in this dissertation, exploring these topics. First, we analyze a population dynamics model describing interactions of sex-structured population groups. Specifically, we analyze how a sex-linked genetic trait's ecological consequence (population survival or extinction) can be influenced by the presence of sex-specific cultural mortality traits, motivated by the desire to expand the theoretical understanding of the role of biased sex ratios in organisms. We analyze dynamics within a single population group, as well as between competing groups. We find that there is a finite range of sex ratio bias that can be maintained in stable equilibrium by sex-specific mortalities. We also find that the outcome of an invasion and the ensuing between-group competition depends not on larger equilibrium group densities, but on the higher allocation of sex-ratio genes. When we extend the model with diffusive dispersal, we find that a critical patch size for achieving positive growth only exists if the population expands into an empty environment. If a resident population is already present that can be exploited by the invading group, then any small seed of invader can advance from rarity, in the mean-field approximation, as long as the local competition dynamics favors the invader's survival. Most spatial models assume initial populations with a uniform distribution inside a finite patch; a simple, but not a cost-efficient approach. We show, using a novel application of simulated annealing, that a specific, non-trivial shape of spatial distribution can minimize the total cost of successful invasion, i.e., the cost of ecological restoration. Further, our approach can be generalized to essentially any reaction-diffusion model with diffusive spreading. In the second part of the dissertation we conduct an extensive study of minimum dominating sets (MDS) in complex networks; particularly, in scale-free networks. MDS is the smallest subset of nodes in a network that can reach every other node as nearest neighbors, thus it provides a key subset of nodes that play critical role in controllability and observability of social, biological, and technological networks. Continued interest in network control, monitoring and influencing of complex networks motivates our research of understanding the properties and practical application-related issues of the MDS. Our study of the scaling behavior reveals that the size of MDS always scales linearly with network size, as long as the power-law degree exponent gamma of the degree distribution is larger than 2. However, when gamma<2, a domination transition occurs, allowing the MDS size to become O(1), leading to easily dominated networks, under certain structural conditions. Motivated by practical applicability in large networks, we develop a new dominating set selection method, derived from probabilistic node selection techniques, which can select small dominating sets without complete network topology information. We also show that the effectiveness of our method, as well as the effectiveness of other heuristics of dominating set selection, strongly depends on the assortativity of networks. Finally, we conduct a numerical study to analyze the fraction of nodes that remain dominated, after the network is damaged, and some nodes are removed. We find that dominating sets optimized for small size are particularly vulnerable to damage; a significant amount of "domination coverage" may be lost if key dominator nodes are deleted. However, we also find that increasing the redundancy of dominating sets by adding a few well-picked nodes can successfully increase the post-damage dominated fraction of the network. Based on this idea, we develop two algorithms to build dominating sets with flexible balance between size and damage resilience.

Excitatory interneurons dominate sensory processing in the spinal substantia gelatinosa of rat

PubMed Central

Santos, Sónia F A; Rebelo, Sandra; Derkach, Victor A; Safronov, Boris V

2007-01-01

Substantia gelatinosa (SG, lamina II) is a spinal cord region where most unmyelinated primary afferents terminate and the central nociceptive processing begins. It is formed by several distinct groups of interneurons whose functional properties and synaptic connections are poorly understood, in part, because recordings from synaptically coupled pairs of SG neurons are quite challenging due to a very low probability of finding connected cells. Here, we describe an efficient method for identifying synaptically coupled interneurons in rat spinal cord slices and characterizing their excitatory or inhibitory function. Using tight-seal whole-cell recordings and a cell-attached stimulation technique, we routinely tested about 1500 SG interneurons, classifying 102 of them as monosynaptically connected to neurons in lamina I–III. Surprisingly, the vast majority of SG interneurons (n = 87) were excitatory and glutamatergic, while only 15 neurons were inhibitory. According to their intrinsic firing properties, these 102 SG neurons were also classified as tonic (n = 49), adapting (n = 17) or delayed-firing neurons (n = 36). All but two tonic neurons and all adapting neurons were excitatory interneurons. Of 36 delayed-firing neurons, 23 were excitatory and 13 were inhibitory. We conclude that sensory integration in the intrinsic SG neuronal network is dominated by excitatory interneurons. Such organization of neuronal circuitries in the spinal SG can be important for nociceptive encoding. PMID:17331995

Inter- and Intrahemispheric Connectivity Differences When Reading Japanese Kanji and Hiragana

PubMed Central

Kawabata Duncan, Keith J.; Twomey, Tae; Parker Jones, ‘Ōiwi; Seghier, Mohamed L.; Haji, Tomoki; Sakai, Katsuyuki; Price, Cathy J.; Devlin, Joseph T.

2014-01-01

Unlike most languages that are written using a single script, Japanese uses multiple scripts including morphographic Kanji and syllabographic Hiragana and Katakana. Here, we used functional magnetic resonance imaging with dynamic causal modeling to investigate competing theories regarding the neural processing of Kanji and Hiragana during a visual lexical decision task. First, a bilateral model investigated interhemispheric connectivity between ventral occipito–temporal (vOT) cortex and Broca's area (“pars opercularis”). We found that Kanji significantly increased the connection strength from right-to-left vOT. This is interpreted in terms of increased right vOT activity for visually complex Kanji being integrated into the left (i.e. language dominant) hemisphere. Secondly, we used a unilateral left hemisphere model to test whether Kanji and Hiragana rely preferentially on ventral and dorsal paths, respectively, that is, they have different intrahemispheric functional connectivity profiles. Consistent with this hypothesis, we found that Kanji increased connectivity within the ventral path (V1 ↔ vOT ↔ Broca's area), and that Hiragana increased connectivity within the dorsal path (V1 ↔ supramarginal gyrus ↔ Broca's area). Overall, the results illustrate how the differential processing demands of Kanji and Hiragana influence both inter- and intrahemispheric interactions. PMID:23382515

Inter- and intrahemispheric connectivity differences when reading Japanese Kanji and Hiragana.

PubMed

Kawabata Duncan, Keith J; Twomey, Tae; Parker Jones, 'Ōiwi; Seghier, Mohamed L; Haji, Tomoki; Sakai, Katsuyuki; Price, Cathy J; Devlin, Joseph T

2014-06-01

Unlike most languages that are written using a single script, Japanese uses multiple scripts including morphographic Kanji and syllabographic Hiragana and Katakana. Here, we used functional magnetic resonance imaging with dynamic causal modeling to investigate competing theories regarding the neural processing of Kanji and Hiragana during a visual lexical decision task. First, a bilateral model investigated interhemispheric connectivity between ventral occipito-temporal (vOT) cortex and Broca's area ("pars opercularis"). We found that Kanji significantly increased the connection strength from right-to-left vOT. This is interpreted in terms of increased right vOT activity for visually complex Kanji being integrated into the left (i.e. language dominant) hemisphere. Secondly, we used a unilateral left hemisphere model to test whether Kanji and Hiragana rely preferentially on ventral and dorsal paths, respectively, that is, they have different intrahemispheric functional connectivity profiles. Consistent with this hypothesis, we found that Kanji increased connectivity within the ventral path (V1 ↔ vOT ↔ Broca's area), and that Hiragana increased connectivity within the dorsal path (V1 ↔ supramarginal gyrus ↔ Broca's area). Overall, the results illustrate how the differential processing demands of Kanji and Hiragana influence both inter- and intrahemispheric interactions.

Genetic algorithm-based multi-objective optimal absorber system for three-dimensional seismic structures

NASA Astrophysics Data System (ADS)

Ren, Wenjie; Li, Hongnan; Song, Gangbing; Huo, Linsheng

2009-03-01

The problem of optimizing an absorber system for three-dimensional seismic structures is addressed. The objective is to determine the number and position of absorbers to minimize the coupling effects of translation-torsion of structures at minimum cost. A procedure for a multi-objective optimization problem is developed by integrating a dominance-based selection operator and a dominance-based penalty function method. Based on the two-branch tournament genetic algorithm, the selection operator is constructed by evaluating individuals according to their dominance in one run. The technique guarantees the better performing individual winning its competition, provides a slight selection pressure toward individuals and maintains diversity in the population. Moreover, due to the evaluation for individuals in each generation being finished in one run, less computational effort is taken. Penalty function methods are generally used to transform a constrained optimization problem into an unconstrained one. The dominance-based penalty function contains necessary information on non-dominated character and infeasible position of an individual, essential for success in seeking a Pareto optimal set. The proposed approach is used to obtain a set of non-dominated designs for a six-storey three-dimensional building with shape memory alloy dampers subjected to earthquake.

The influence of phylogeny, social style, and sociodemographic factors on macaque social network structure.

PubMed

Balasubramaniam, Krishna N; Beisner, Brianne A; Berman, Carol M; De Marco, Arianna; Duboscq, Julie; Koirala, Sabina; Majolo, Bonaventura; MacIntosh, Andrew J; McFarland, Richard; Molesti, Sandra; Ogawa, Hideshi; Petit, Odile; Schino, Gabriele; Sosa, Sebastian; Sueur, Cédric; Thierry, Bernard; de Waal, Frans B M; McCowan, Brenda

2018-01-01

Among nonhuman primates, the evolutionary underpinnings of variation in social structure remain debated, with both ancestral relationships and adaptation to current conditions hypothesized to play determining roles. Here we assess whether interspecific variation in higher-order aspects of female macaque (genus: Macaca) dominance and grooming social structure show phylogenetic signals, that is, greater similarity among more closely-related species. We use a social network approach to describe higher-order characteristics of social structure, based on both direct interactions and secondary pathways that connect group members. We also ask whether network traits covary with each other, with species-typical social style grades, and/or with sociodemographic characteristics, specifically group size, sex-ratio, and current living condition (captive vs. free-living). We assembled 34-38 datasets of female-female dyadic aggression and allogrooming among captive and free-living macaques representing 10 species. We calculated dominance (transitivity, certainty), and grooming (centrality coefficient, Newman's modularity, clustering coefficient) network traits as aspects of social structure. Computations of K statistics and randomization tests on multiple phylogenies revealed moderate-strong phylogenetic signals in dominance traits, but moderate-weak signals in grooming traits. GLMMs showed that grooming traits did not covary with dominance traits and/or social style grade. Rather, modularity and clustering coefficient, but not centrality coefficient, were strongly predicted by group size and current living condition. Specifically, larger groups showed more modular networks with sparsely-connected clusters than smaller groups. Further, this effect was independent of variation in living condition, and/or sampling effort. In summary, our results reveal that female dominance networks were more phylogenetically conserved across macaque species than grooming networks, which were more labile to sociodemographic factors. Such findings narrow down the processes that influence interspecific variation in two core aspects of macaque social structure. Future directions should include using phylogeographic approaches, and addressing challenges in examining the effects of socioecological factors on primate social structure. © 2017 Wiley Periodicals, Inc.

Fish communities in coastal freshwater ecosystems: the role of the physical and chemical setting

PubMed Central

Arend, Kristin K; Bain, Mark B

2008-01-01

Background We explored how embayment watershed inputs, morphometry, and hydrology influence fish community structure among eight embayments located along the southeastern shoreline of Lake Ontario, New York, USA. Embayments differed in surface area and depth, varied in their connections to Lake Ontario and their watersheds, and drained watersheds representing a gradient of agricultural to forested land use. Results We related various physicochemical factors, including total phosphorus load, embayment area, and submerged vegetation, to differences in fish species diversity and community relative abundance, biomass, and size structure both among and within embayments. Yellow perch (Perca flavescens) and centrarchids numerically dominated most embayment fish communities. Biomass was dominated by piscivorous fishes including brown bullhead (Ameiurus nebulosus), bowfin (Amia calva), and northern pike (Esox lucius). Phosphorus loading influenced relative biomass, but not species diversity or relative abundance. Fish relative abundance differed among embayments; within embayments, fish abundance at individual sampling stations increased significantly with submerged vegetative cover. Relative biomass differed among embayments and was positively related to total phophorus loading and embayment area. Fish community size structure, based on size spectra analysis, differed among embayments, with the frequency of smaller-bodied fishes positively related to percent vegetation. Conclusion The importance of total phosphorus loading and vegetation in structuring fish communities has implications for anthropogenic impacts to embayment fish communities through activities such as farming and residential development, reduction of cultural eutrophication, and shoreline development and maintenance. PMID:19114002

Visual navigation in adolescents with early periventricular lesions: knowing where, but not getting there.

PubMed

Pavlova, Marina; Sokolov, Alexander; Krägeloh-Mann, Ingeborg

2007-02-01

Visual navigation in familiar and unfamiliar surroundings is an essential ingredient of adaptive daily life behavior. Recent brain imaging work helps to recognize that establishing connectivity between brain regions is of importance for successful navigation. Here, we ask whether the ability to navigate is impaired in adolescents who were born premature and suffer congenital bilateral periventricular brain damage that might affect the pathways interconnecting subcortical structures with cortex. Performance on a set of visual labyrinth tasks was significantly worse in patients with periventricular leukomalacia (PVL) as compared with premature-born controls without lesions and term-born adolescents. The ability for visual navigation inversely relates to the severity of motor disability, leg-dominated bilateral spastic cerebral palsy. This agrees with the view that navigation ability substantially improves with practice and might be compromised in individuals with restrictions in active spatial exploration. Visual navigation is negatively linked to the volumetric extent of lesions over the right parietal and frontal periventricular regions. Whereas impairments of visual processing of point-light biological motion are associated in patients with PVL with bilateral parietal periventricular lesions, navigation ability is specifically linked to the frontal lesions in the right hemisphere. We suggest that more anterior periventricular lesions impair the interrelations between the right hippocampus and cortical areas leading to disintegration of neural networks engaged in visual navigation. For the first time, we show that the severity of right frontal periventricular damage and leg-dominated motor disorders can serve as independent predictors of the visual navigation disability.

Terrestrial water fluxes dominated by transpiration.

PubMed

Jasechko, Scott; Sharp, Zachary D; Gibson, John J; Birks, S Jean; Yi, Yi; Fawcett, Peter J

2013-04-18

Renewable fresh water over continents has input from precipitation and losses to the atmosphere through evaporation and transpiration. Global-scale estimates of transpiration from climate models are poorly constrained owing to large uncertainties in stomatal conductance and the lack of catchment-scale measurements required for model calibration, resulting in a range of predictions spanning 20 to 65 per cent of total terrestrial evapotranspiration (14,000 to 41,000 km(3) per year) (refs 1, 2, 3, 4, 5). Here we use the distinct isotope effects of transpiration and evaporation to show that transpiration is by far the largest water flux from Earth's continents, representing 80 to 90 per cent of terrestrial evapotranspiration. On the basis of our analysis of a global data set of large lakes and rivers, we conclude that transpiration recycles 62,000 ± 8,000 km(3) of water per year to the atmosphere, using half of all solar energy absorbed by land surfaces in the process. We also calculate CO2 uptake by terrestrial vegetation by connecting transpiration losses to carbon assimilation using water-use efficiency ratios of plants, and show the global gross primary productivity to be 129 ± 32 gigatonnes of carbon per year, which agrees, within the uncertainty, with previous estimates. The dominance of transpiration water fluxes in continental evapotranspiration suggests that, from the point of view of water resource forecasting, climate model development should prioritize improvements in simulations of biological fluxes rather than physical (evaporation) fluxes.

BRAIN NETWORKS. Correlated gene expression supports synchronous activity in brain networks.

PubMed

Richiardi, Jonas; Altmann, Andre; Milazzo, Anna-Clare; Chang, Catie; Chakravarty, M Mallar; Banaschewski, Tobias; Barker, Gareth J; Bokde, Arun L W; Bromberg, Uli; Büchel, Christian; Conrod, Patricia; Fauth-Bühler, Mira; Flor, Herta; Frouin, Vincent; Gallinat, Jürgen; Garavan, Hugh; Gowland, Penny; Heinz, Andreas; Lemaître, Hervé; Mann, Karl F; Martinot, Jean-Luc; Nees, Frauke; Paus, Tomáš; Pausova, Zdenka; Rietschel, Marcella; Robbins, Trevor W; Smolka, Michael N; Spanagel, Rainer; Ströhle, Andreas; Schumann, Gunter; Hawrylycz, Mike; Poline, Jean-Baptiste; Greicius, Michael D

2015-06-12

During rest, brain activity is synchronized between different regions widely distributed throughout the brain, forming functional networks. However, the molecular mechanisms supporting functional connectivity remain undefined. We show that functional brain networks defined with resting-state functional magnetic resonance imaging can be recapitulated by using measures of correlated gene expression in a post mortem brain tissue data set. The set of 136 genes we identify is significantly enriched for ion channels. Polymorphisms in this set of genes significantly affect resting-state functional connectivity in a large sample of healthy adolescents. Expression levels of these genes are also significantly associated with axonal connectivity in the mouse. The results provide convergent, multimodal evidence that resting-state functional networks correlate with the orchestrated activity of dozens of genes linked to ion channel activity and synaptic function. Copyright © 2015, American Association for the Advancement of Science.

Uniting paradigms of connectivity in marine ecology.

PubMed

Brown, Christopher J; Harborne, Alastair R; Paris, Claire B; Mumby, Peter J

2016-09-01

The connectivity of marine organisms among habitat patches has been dominated by two independent paradigms with distinct conservation strategies. One paradigm is the dispersal of larvae on ocean currents, which suggests networks of marine reserves. The other is the demersal migration of animals from nursery to adult habitats, requiring the conservation of connected ecosystem corridors. Here, we suggest that a common driver, wave exposure, links larval and demersal connectivity across the seascape. To study the effect of linked connectivities on fish abundance at reefs, we parameterize a demographic model for The Bahamas seascape using maps of habitats, empirically forced models of wave exposure and spatially realistic three-dimensional hydrological models of larval dispersal. The integrated empirical-modeling approach enabled us to study linked connectivity on a scale not currently possible by purely empirical studies. We find sheltered environments not only provide greater nursery habitat for juvenile fish but larvae spawned on adjacent reefs have higher retention, thereby creating a synergistic increase in fish abundance. Uniting connectivity paradigms to consider all life stages simultaneously can help explain the evolution of nursery habitat use and simplifies conservation advice: Reserves in sheltered environments have desirable characteristics for biodiversity conservation and can support local fisheries through adult spillover. © 2016 by the Ecological Society of America.

Analysis of the dominant vibration frequencies of rail bridges for structure-borne noise using a power flow method

NASA Astrophysics Data System (ADS)

Li, Q.; Wu, D. J.

2013-09-01

The use of concrete bridges in urban rail transit systems has raised many concerns regarding low-frequency (20-200 Hz) structure-borne noise due to the vibration of bridges when subjected to moving trains. Understanding the mechanism that determines the dominant frequencies of bridge vibrations is essential for both vibration and noise reduction. This paper presents a general procedure based on the force method to obtain the power flows within a coupled vehicle-track-bridge system, the point mobility of the system and the dynamic interaction forces connecting various components. The general coupling system consists of multi-rigid-bodies for the vehicles, infinite Euler beams representing the rails, two-dimensional or three-dimensional elements of the concrete bridges, and spring-dashpot pairs to model the wheel-rail contacts, the vehicle suspensions, the rail pads and the bridge bearings. The dynamic interaction of the coupled system is solved in the frequency domain by assuming the combined wheel-rail roughness moves forward relative to the stationary vehicles. The proposed procedure is first applied to a rail on discrete supports and then to a real urban rail transit U-shaped concrete bridge. The computed results show that the wheel-rail contact forces, the power flows to the rail/bridge subsystem and the accelerations of the bridge are primarily dominated by the contents around the natural frequency of a single wheel adhered to the elastically supported rail. If the ath node of the mth spring-dashpot pair and the bth node of the nth spring-dashpot pair are connected to the same rigid body, then δmnab(ω) can be expressed as δmnab(ω)=-{(}/{Mlω}, where Ml is the mass of the lth rigid body. If the ath node of the mth spring-dashpot pair and the bth node of the nth spring-dashpot pair are connected to the same infinite rail, δmnab(ω) can be expressed as [8] δmnab(ω)=-j{((e-je)}/{4EIk}, where xm and xn are the x-coordinates of the mth and nth spring-dashpot pairs respectively; E and I denote the elastic module and the bending moment of inertia of the infinite rail; and k is the wavenumber of the unsupported infinite rail k=(EI)1/4, where mr is the mass per unit length of the rail. If the ath node of the mth spring-dashpot pair and the bth node of the nth spring-dashpot pair are connected to the same bridge component, then δmnab(ω) can be obtained by applying the mode superposition method δmnab(ω)=∑i=1Nl{(ϕ}/{liaϕlibωli2-ω+2jξωω}, where ω and ξ are the damped natural frequency and damping ratio of the ith mode of the lth bridge component; ϕlia and ϕlib denote the generalised mode shape amplitudes of the the lth bridge component to which the ath and bth nodes of the two spring-dashpot pairs are connected; and Nl is the mode number of interest. It can be observed from Eqs. (2)-(7) that the theorem of reciprocal displacements is met as follows: δ(ω)=δ(ω). An external point excitation can be regarded as a force produced by a spring-dashpot pair with its first node connected to the excitation point and the second node fixed to the ground. Therefore, each element in vector ΔP(ω) can be easily attained using the first and last terms of Eq. (3): Δmp(ω)=δmp11(ω)+δmp21(ω), where the subscript p denotes the fictitious spring-dashpot pair used to simulate the external harmonic force. The dominant frequency of the wheel-rail contact forces and power input to the rail on elastic supports is found to be consistent with the natural frequency of the single wheel adhered to the elastically supported rail. The simple formula derived to predict this dominant frequency matches well with the numerical results. The acceleration response of the bridge is also dominated by the natural frequency of the single wheel adhered to the elastically supported rail. Although the vehicle speed has an insignificant effect on the dominant frequency of the bridge response, it does influence the magnitude of the response. The findings in this paper and the proposed method can be applied to mitigate the vibration and noise from rail bridges once a series of parametric analyses has been carried out.

Dynamic Causal Modeling of Preclinical Autosomal-Dominant Alzheimer's Disease.

PubMed

Penny, Will; Iglesias-Fuster, Jorge; Quiroz, Yakeel T; Lopera, Francisco Javier; Bobes, Maria A

2018-03-16

Dynamic causal modeling (DCM) is a framework for making inferences about changes in brain connectivity using neuroimaging data. We fitted DCMs to high-density EEG data from subjects performing a semantic picture matching task. The subjects are carriers of the PSEN1 mutation, which leads to early onset Alzheimer's disease, but at the time of EEG acquisition in 1999, these subjects were cognitively unimpaired. We asked 1) what is the optimal model architecture for explaining the event-related potentials in this population, 2) which connections are different between this Presymptomatic Carrier (PreC) group and a Non-Carrier (NonC) group performing the same task, and 3) which network connections are predictive of subsequent Mini-Mental State Exam (MMSE) trajectories. We found 1) a model with hierarchical rather than lateral connections between hemispheres to be optimal, 2) that a pathway from right inferotemporal cortex (IT) to left medial temporal lobe (MTL) was preferentially activated by incongruent items for subjects in the PreC group but not the NonC group, and 3) that increased effective connectivity among left MTL, right IT, and right MTL was predictive of subsequent MMSE scores.

38 CFR 17.37 - Enrollment not required-provision of hospital and outpatient care to veterans.

Code of Federal Regulations, 2010 CFR

2010-07-01

... healthcare system: (a) A veteran rated for service-connected disabilities at 50 percent or greater will... a service-connected disability will receive VA care provided for in the “medical benefits package” set forth in § 17.38 for that service-connected disability. (c) A veteran who was discharged or...

Social Connection and Psychological Outcomes in a Physical Activity-Based Youth Development Setting

ERIC Educational Resources Information Center

Ullrich-French, Sarah; McDonough, Meghan H.; Smith, Alan L.

2012-01-01

It is believed that the social connections formed by participating in physical activity-based positive youth development (PYD) programs contributes to building personal and social assets. In this study, we examined how changes in social connection over a physical activity-based PYD program for low-income youth were associated with changes in…

Education/Connection/Action: Community Literacies and Shared Knowledges as Creative Productions for Social Justice

ERIC Educational Resources Information Center

Licona, Adela C.; Gonzales, J. Sarah

2013-01-01

This article highlights Education/Connection/Action (ECA), a locally developed community pedagogy deployed at a youth activism summer camp that served as a site for a community/academic teaching and research collaboration. Youth considered connections between a set of issues, including a local ban on Ethnic Studies, the School-to-Prison Pipeline,…

Permeability of three-dimensional rock masses containing geomechanically-grown anisotropic fracture networks

NASA Astrophysics Data System (ADS)

Thomas, R. N.; Ebigbo, A.; Paluszny, A.; Zimmerman, R. W.

2016-12-01

The macroscopic permeability of 3D anisotropic geomechanically-generated fractured rock masses is investigated. The explicitly computed permeabilities are compared to the predictions of classical inclusion-based effective medium theories, and to the permeability of networks of randomly oriented and stochastically generated fractures. Stochastically generated fracture networks lack features that arise from fracture interaction, such as non-planarity, and termination of fractures upon intersection. Recent discrete fracture network studies include heuristic rules that introduce these features to some extent. In this work, fractures grow and extend under tension from a finite set of initial flaws. The finite element method is used to compute displacements, and modal stress intensity factors are computed around each fracture tip using the interaction integral accumulated over a set of virtual discs. Fracture apertures emerge as a result of simulations that honour the constraints of stress equilibrium and mass conservation. The macroscopic permeabilities are explicitly calculated by solving the local cubic law in the fractures, on an element-by-element basis, coupled to Darcy's law in the matrix. The permeabilities are then compared to the estimates given by the symmetric and asymmetric versions of the self-consistent approximation, which, for randomly fractured volumes, were previously demonstrated to be most accurate of the inclusion-based effective medium methods (Ebigbo et al., Transport in Porous Media, 2016). The permeabilities of several dozen geomechanical networks are computed as a function of density and in situ stresses. For anisotropic networks, we find that the asymmetric and symmetric self-consistent methods overestimate the effective permeability in the direction of the dominant fracture set. Effective permeabilities that are more strongly dependent on the connectivity of two or more fracture sets are more accurately captured by the effective medium models.

Multi-factorial modulation of hemispheric specialization and plasticity for language in healthy and pathological conditions: A review.

PubMed

Tzourio-Mazoyer, Nathalie; Perrone-Bertolotti, Marcela; Jobard, Gael; Mazoyer, Bernard; Baciu, Monica

2017-01-01

This review synthesizes anatomo-functional variability of language hemispheric representation and specialization (hemispheric specialization for language, HSL) as well as its modulation by several variables (demographic, anatomical, developmental, genetic, clinical, and psycholinguistic) in physiological and pathological conditions. The left hemisphere (LH) dominance for language, observed in approximately 90% of healthy individuals and in 70% of patients, is grounded by intra-hemispheric connections mediated by associative bundles such as the arcuate fasciculus and inter-hemispheric transcallosal connections mediated by the corpus callosum that connects homotopic regions of the left and right hemispheres (RH). In typical brains, inter-hemispheric inhibition, exerted from the LH to the RH, permits the LH to maintain language dominance. In pathological conditions, inter- and intra-hemispheric inhibition is decreased, inducing modifications on the degree of HSL and of language networks. HSL evaluation is classically performed in clinical practice with the Wada test and electro-cortical stimulation, gold standard methods. The advent of functional neuroimaging has allowed a more detailed assessment of the language networks and their lateralization, consistent with the results provided by the gold standard methods. In the first part, we describe anatomo-functional support for HSL in healthy conditions, its developmental course, its relationship with cognitive skills, and the various modulatory factors acting on HSL. The second section is devoted to the assessment of HSL in patients with focal and drug-resistant epilepsy (FDRE). FDRE is considered a neurological model associated with patterns of language plasticity, both before and after surgery: FDRE patients show significant modification of language networks induced by changes mediated by transcallosal connections (explaining inter-hemispheric patterns of language reorganization) or collateral connections (explaining intra-hemispheric patterns of language reorganization). Finally, we propose several predictive and explicative models of language organization and reorganization. Copyright © 2016 Elsevier Ltd. All rights reserved.

Exploring drivers of wetland hydrologic fluxes across parameters and space

NASA Astrophysics Data System (ADS)

Jones, C. N.; Cheng, F. Y.; Mclaughlin, D. L.; Basu, N. B.; Lang, M.; Alexander, L. C.

2017-12-01

Depressional wetlands provide diverse ecosystem services, ranging from critical habitat to the regulation of landscape hydrology. The latter is of particular interest, because while hydrologic connectivity between depressional wetlands and downstream waters has been a focus of both scientific research and policy, it remains difficult to quantify the mode, magnitude, and timing of this connectivity at varying spatial and temporary scales. To do so requires robust empirical and modeling tools that accurately represent surface and subsurface flowpaths between depressional wetlands and other landscape elements. Here, we utilize a parsimonious wetland hydrology model to explore drivers of wetland water fluxes in different archetypal wetland-rich landscapes. We validated the model using instrumented sites from regions that span North America: Prairie Pothole Region (south-central Canada), Delmarva Peninsula (Mid-Atlantic Coastal Plain), and Big Cypress Swamp (southern Florida). Then, using several national scale datasets (e.g., National Wetlands Inventory, USFWS; National Hydrography Dataset, USGS; Soil Survey Geographic Database, NRCS), we conducted a global sensitivity analysis to elucidate dominant drivers of simulated fluxes. Finally, we simulated and compared wetland hydrology in five contrasting landscapes dominated by depressional wetlands: prairie potholes, Carolina and Delmarva bays, pocosins, western vernal pools, and Texas coastal prairie wetlands. Results highlight specific drivers that vary across these regions. Largely, hydroclimatic variables (e.g., PET/P ratios) controlled the timing and magnitude of wetland connectivity, whereas both wetland morphology (e.g., storage capacity and watershed size) and soil characteristics (e.g., ksat and confining layer depth) controlled the duration and mode (surface vs. subsurface) of wetland connectivity. Improved understanding of the drivers of wetland hydrologic connectivity supports enhanced, region-specific management and conservation of these critical ecosystems through more informed decision-making. Findings and conclusions expressed in this article are those of the authors and do not necessarily reflect the views or policies of the US EPA or USFWS.

Impact of 36 h of total sleep deprivation on resting-state dynamic functional connectivity.

PubMed

Xu, Huaze; Shen, Hui; Wang, Lubin; Zhong, Qi; Lei, Yu; Yang, Liu; Zeng, Ling-Li; Zhou, Zongtan; Hu, Dewen; Yang, Zheng

2018-06-01

Resting-state functional magnetic resonance imaging (fMRI) studies using static functional connectivity (sFC) measures have shown that the brain function is severely disrupted after long-term sleep deprivation (SD). However, increasing evidence has suggested that resting-state functional connectivity (FC) is dynamic and exhibits spontaneous fluctuation on a smaller timescale. The process by which long-term SD can influence dynamic functional connectivity (dFC) remains unclear. In this study, 37 healthy subjects participated in the SD experiment, and they were scanned both during rested wakefulness (RW) and after 36 h of SD. A sliding-window based approach and a spectral clustering algorithm were used to evaluate the effects of SD on dFC based on the 26 qualified subjects' data. The outcomes showed that time-averaging FC across specific regions as well as temporal properties of the FC states, such as the dwell time and transition probability, was strongly influenced after SD in contrast to the RW condition. Based on the occurrences of FC states, we further identified some RW-dominant states characterized by anti-correlation between the default mode network (DMN) and other cortices, and some SD-dominant states marked by significantly decreased thalamocortical connectivity. In particular, the temporal features of these FC states were negatively correlated with the correlation coefficients between the DMN and dorsal attention network (dATN) and demonstrated high potential in classification of sleep state (with 10-fold cross-validation accuracy of 88.6% for dwell time and 88.1% for transition probability). Collectively, our results suggested that the temporal properties of the FC states greatly account for changes in the resting-state brain networks following SD, which provides new insights into the impact of SD on the resting-state functional organization in the human brain. Copyright © 2017. Published by Elsevier B.V.

Glacial Boundary Features Delineated Using Enhanced-resolution Passive-microwave Data to Determine Melt Season Variation of the Vatnajokull Ice Cap, Iceland

NASA Astrophysics Data System (ADS)

Marzillier, D. M.; Ramage, J. M.

2017-12-01

Temperate glaciers such as those seen in Iceland experience high annual mass flux, thereby responding to small scale changes in Earth's climate. Decadal changes in the glacial margins of Iceland's ice caps are observable in the Landsat record, however twice daily AMSR-E Calibrated Enhanced-Resolution Passive Microwave Daily EASE-Grid 2.0 Brightness Temperature (CETB) Earth System Data Record (ESDR) allow for observation on a daily temporal scale and a 3.125 km spatial scale, which can in turn be connected to patterns seen over longer periods of time. Passive microwave data allow for careful observation of melt onset and duration in Iceland's glacial regions by recording changes in emissivity of the ice surface, known as brightness temperature (TB), which is sensitive to fluctuations in the liquid water content of snow and ice seen during melting in glaciated regions. Enhanced resolution of this data set allows for a determination of a threshold that defines the melting season. The XPGR snowmelt algorithm originally presented by Abdalati and Steffen (1995) is used as a comparison with the diurnal amplitude variation (DAV) values on Iceland's Vatnajokull ice cap located at 64.4N, -16.8W. Ground-based air temperature data in this region, digital elevation models (DEMs), and river discharge dominated by glacial runoff are used to confirm the glacial response to changes in global climate. Results show that Iceland glaciers have a bimodal distribution of brightness temperature delineating when the snow/ice is melting and refreezing. Ground based temperatures have increased on a decadal trend. Clear glacial boundaries are visible on the passive microwave delineating strong features, and we are working to understand their variability and contribution to glacier evolution. The passive microwave data set allows connections to be made between observations seen on a daily scale and the long term glacier changes observed by the Landsat satellite record that integrates the overall glacier changes.

Amygdala subnuclei connectivity in response to violence reveals unique influences of individual differences in psychopathic traits in a non-forensic sample

PubMed Central

Yoder, Keith J.; Porges, Eric C.; Decety, Jean

2016-01-01

Atypical amygdala function and connectivity have reliably been associated with psychopathy. However, the amygdala is not a unitary structure. To examine how psychopathic traits in a non-forensic sample are linked to amygdala response to violence, the current study used probabilistic tractography to classify amygdala subnuclei based on anatomical projections to and from amygdala subnuclei in a group of 43 male participants. The segmentation identified the basolateral complex (BLA; lateral, basal, and accessory basal subnuclei) and the central subnucleus (CE), which were used as seeds in a functional connectivity analysis to identify differences in neuronal coupling specific to observed violence. While a full amygdala seed showed significant connectivity only to right middle occipital gyrus, subnuclei seeds revealed unique connectivity patterns. BLA showed enhanced coupling with anterior cingulate and prefrontal regions, while CE showed increased connectivity with the brainstem, but reduced connectivity with superior parietal and precentral gyrus. Further, psychopathic personality factors were related to specific patterns of connectivity. Fearless Dominance scores on the psychopathic personality inventory predicted increased coupling between the BLA seed and sensory integration cortices, and increased connectivity between the CE seed and posterior insula. Conversely, Self-Centered Impulsivity scores were negatively correlated with coupling between BLA and ventrolateral prefrontal cortex, and Coldheartedness scores predicted increased functional connectivity between BLA and dorsal anterior cingulate cortex. Taken together, these findings demonstrate how subnuclei segmentations reveal important functional connectivity differences that are otherwise inaccessible. Such an approach yields a better understanding of amygdala dysfunction in psychopathy. PMID:25557777

Effects of Neuromodulation on Excitatory-Inhibitory Neural Network Dynamics Depend on Network Connectivity Structure

NASA Astrophysics Data System (ADS)

Rich, Scott; Zochowski, Michal; Booth, Victoria

2018-01-01

Acetylcholine (ACh), one of the brain's most potent neuromodulators, can affect intrinsic neuron properties through blockade of an M-type potassium current. The effect of ACh on excitatory and inhibitory cells with this potassium channel modulates their membrane excitability, which in turn affects their tendency to synchronize in networks. Here, we study the resulting changes in dynamics in networks with inter-connected excitatory and inhibitory populations (E-I networks), which are ubiquitous in the brain. Utilizing biophysical models of E-I networks, we analyze how the network connectivity structure in terms of synaptic connectivity alters the influence of ACh on the generation of synchronous excitatory bursting. We investigate networks containing all combinations of excitatory and inhibitory cells with high (Type I properties) or low (Type II properties) modulatory tone. To vary network connectivity structure, we focus on the effects of the strengths of inter-connections between excitatory and inhibitory cells (E-I synapses and I-E synapses), and the strengths of intra-connections among excitatory cells (E-E synapses) and among inhibitory cells (I-I synapses). We show that the presence of ACh may or may not affect the generation of network synchrony depending on the network connectivity. Specifically, strong network inter-connectivity induces synchronous excitatory bursting regardless of the cellular propensity for synchronization, which aligns with predictions of the PING model. However, when a network's intra-connectivity dominates its inter-connectivity, the propensity for synchrony of either inhibitory or excitatory cells can determine the generation of network-wide bursting.

Amygdala subnuclei connectivity in response to violence reveals unique influences of individual differences in psychopathic traits in a nonforensic sample.

PubMed

Yoder, Keith J; Porges, Eric C; Decety, Jean

2015-04-01

Atypical amygdala function and connectivity have reliably been associated with psychopathy. However, the amygdala is not a unitary structure. To examine how psychopathic traits in a nonforensic sample are linked to amygdala response to violence, this study used probabilistic tractography to classify amygdala subnuclei based on anatomical projections to and from amygdala subnuclei in a group of 43 male participants. The segmentation identified the basolateral complex (BLA; lateral, basal, and accessory basal subnuclei) and the central subnucleus (CE), which were used as seeds in a functional connectivity analysis to identify differences in neuronal coupling specific to observed violence. While a full amygdala seed showed significant connectivity only to right middle occipital gyrus, subnuclei seeds revealed unique connectivity patterns. BLA showed enhanced coupling with anterior cingulate and prefrontal regions, while CE showed increased connectivity with the brainstem, but reduced connectivity with superior parietal and precentral gyrus. Further, psychopathic personality factors were related to specific patterns of connectivity. Fearless Dominance scores on the psychopathic personality inventory predicted increased coupling between the BLA seed and sensory integration cortices, and increased connectivity between the CE seed and posterior insula. Conversely, Self-Centered Impulsivity scores were negatively correlated with coupling between BLA and ventrolateral prefrontal cortex, and Coldheartedness scores predicted increased functional connectivity between BLA and dorsal anterior cingulate cortex. Taken together, these findings demonstrate how subnuclei segmentations reveal important functional connectivity differences that are otherwise inaccessible. Such an approach yields a better understanding of amygdala dysfunction in psychopathy. © 2014 Wiley Periodicals, Inc.

Do well-connected landscapes promote road-related mortality?

USGS Publications Warehouse

Grilo, C.; Ascensao, F.; Santos-Reis, M.; Bissonette, J.A.

2011-01-01

Cost surface (CS) models have emerged as a useful tool to examine the interactions between landscapes patterns and wildlife at large-scale extents. This approach is particularly relevant to guide conservation planning for species that show vulnerability to road networks in human-dominated landscapes. In this study, we measured the functional connectivity of the landscape in southern Portugal and examined how it may be related to stone marten road mortality risk. We addressed three questions: (1) How different levels of landscape connectivity influence stone marten occurrence in montado patches? (2) Is there any relation between montado patches connectivity and stone marten road mortality risk? (3) If so, which road-related features might be responsible for the species' high road mortality? We developed a series of connectivity models using CS scenarios with different resistance values given to each vegetation cover type to reflect different resistance to species movement. Our models showed that the likelihood of occurrence of stone marten decreased with distance to source areas, meaning continuous montado. Open areas and riparian areas within open area matrices entailed increased costs. We found higher stone marten mortality on roads in well-connected areas. Road sinuosity was an important factor influencing the mortality in those areas. This result challenges the way that connectivity and its relation to mortality has been generally regarded. Clearly, landscape connectivity and road-related mortality are not independent. ?? 2010 Springer-Verlag.

Hydrologic connectivity between landscapes and streams: Transferring reach‐ and plot‐scale understanding to the catchment scale

USGS Publications Warehouse

Jencso, Kelsey G.; McGlynn, Brian L.; Gooseff, Michael N.; Wondzell, Steven M.; Bencala, Kenneth E.; Marshall, Lucy A.

2009-01-01

The relationship between catchment structure and runoff characteristics is poorly understood. In steep headwater catchments with shallow soils the accumulation of hillslope area (upslope accumulated area (UAA)) is a hypothesized first‐order control on the distribution of soil water and groundwater. Hillslope‐riparian water table connectivity represents the linkage between the dominant catchment landscape elements (hillslopes and riparian zones) and the channel network. Hydrologic connectivity between hillslope‐riparian‐stream (HRS) landscape elements is heterogeneous in space and often temporally transient. We sought to test the relationship between UAA and the existence and longevity of HRS shallow groundwater connectivity. We quantified water table connectivity based on 84 recording wells distributed across 24 HRS transects within the Tenderfoot Creek Experimental Forest (U.S. Forest Service), northern Rocky Mountains, Montana. Correlations were observed between the longevity of HRS water table connectivity and the size of each transect's UAA (r2 = 0.91). We applied this relationship to the entire stream network to quantify landscape‐scale connectivity through time and ascertain its relationship to catchment‐scale runoff dynamics. We found that the shape of the estimated annual landscape connectivity duration curve was highly related to the catchment flow duration curve (r2 = 0.95). This research suggests internal catchment landscape structure (topography and topology) as a first‐order control on runoff source area and whole catchment response characteristics.

Using stable isotopes to identify the scaling effects of riparian peatlands on runoff generation processes and DOC mobilisation

NASA Astrophysics Data System (ADS)

Tunaley, Claire; Tetzlaff, Doerthe; Soulsby, Chris

2017-04-01

Knowledge of hydrological sources, flow paths, and their connectivity is fundamental to understanding stream flow generation and surface water quality in peatlands. Stable isotopes are proven tools for tracking the sources and flow paths of runoff. However, relativity few studies have used isotopes in peat-dominated catchments. Here, we combined 13 months (June 2014 - July 2015) of daily isotope measurements in stream water with daily DOC and 15 minute FDOM (fluorescent component of dissolved organic matter) data, at three nested scales in NE Scotland, to identify the hydrological processes occurring in riparian peatlands. We investigated how runoff generation processes in a small, riparian peatland dominated headwater catchment (0.65 km2) propagate to larger scales (3.2 km2 and 31 km2) with decreasing percentage of riparian peatland coverage. Isotope damping was most pronounced in the 0.65 km2 catchment due to high water storage in the organic soils which encouraged tracer mixing and resulted in attenuated runoff peaks. At the largest scale, stream flow and water isotope dynamics showed a more flashy response. Particularly insightful in this study was calculating the deviation of the isotopes from the local meteoric water line, the lc-excess. The lc-excess revealed evaporative fractionation in the peatland dominated catchment, particularly during summer low flows. This implied high hydrological connectivity in the form of constant seepage from the peatlands sustaining high baseflows at the headwater scale. This constant connectivity resulted in high DOC concentrations at the peatland site during baseflow ( 5 mg l-1). In contrast, at the larger scales, DOC was minimal during low flows ( 2 mg l-1) due to increased groundwater influence and the disconnection between DOC sources and the stream. Insights into event dynamics through the analysis of DOC hysteresis loops showed slight dilution on the rising limb, the strong influence of dry antecedent conditions and a quick recovery between events at the riparian peatland site. Again, these dynamics were driven by the tight coupling and high connectivity of the landscape to the stream. At larger scales, the disconnection between the landscape units increased and the variable connectivity controlled runoff generation and DOC dynamics. The results presented here suggest that the hydrological processes occurring in riparian peatlands in headwater catchments are less evident at larger scales which may have implications for the larger scale impact of peatland restoration projects.

Evolving dynamics of trading behavior based on coordination game in complex networks

NASA Astrophysics Data System (ADS)

Bian, Yue-tang; Xu, Lu; Li, Jin-sheng

2016-05-01

This work concerns the modeling of evolvement of trading behavior in stock markets. Based on the assumption of the investors' limited rationality, the evolution mechanism of trading behavior is modeled according to the investment strategy of coordination game in network, that investors are prone to imitate their neighbors' activity through comprehensive analysis on the risk dominance degree of certain investment behavior, the network topology of their relationship and its heterogeneity. We investigate by mean-field analysis and extensive simulations the evolution of investors' trading behavior in various typical networks under different risk dominance degree of investment behavior. Our results indicate that the evolution of investors' behavior is affected by the network structure of stock market and the effect of risk dominance degree of investment behavior; the stability of equilibrium states of investors' behavior dynamics is directly related with the risk dominance degree of some behavior; connectivity and heterogeneity of the network plays an important role in the evolution of the investment behavior in stock market.

Environmental setting of the Yellowstone River basin, Montana, North Dakota, and Wyoming

USGS Publications Warehouse

Zelt, Ronald B.; Boughton, G.K.; Miller, K.A.; Mason, J.P.; Gianakos, L.M.

1999-01-01

Natural and anthropogenic factors influence water-quality conditions in the Yellowstone River Basin. Physiography parallels the structural geologic setting that is generally composed of several uplifts and structural basins. Contrasts in climate and vegetation reflect topographic controls and the midcontinental location of the study unit. Surface-water hydrology reflects water surpluses in mountainous areas that are dominated by snowmelt runoff, and arid to semiarid conditions in the plains that are dissected by typically irrigated valleys in the remainder of the study unit. Principal shallow aquifers are Tertiary sandstones and unconsolidated Quaternary deposits. Human population, though sparsely distributed in general, is growing most rapidly in a few urban centers and resort areas, mostly in the northwestern part of the basin. Land use is areally dominated by grazing in the basins and plains and economically dominated by mineral-extraction activities. Forests are the dominant land cover in mountainous areas. Cropland is a major land use in principal stream valleys. Water use is dominated by irrigated agriculture overall, but mining and public-supply facilities are major users of ground water. Coal and hydrocarbon production and reserves distinguish the Yellowstone River Basin as a principal energy-minerals resources region. Current metallic ore production or reserves are nationally significant for platinum-group elements and chromium.The study unit was subdivided as an initial environmental stratification for use in designing the National Water-Quality Assessment Program investigation that began in 1997. Ecoregions, geologic groups, mineral-resource areas, and general land-cover and land-use categories were used in combination to define 18 environmental settings in the Yellowstone River Basin. It is expected that these different settings will be reflected in differing water-quality or aquatic-ecological characteristics.

Automated Segmentation of Kidneys from MR Images in Patients with Autosomal Dominant Polycystic Kidney Disease

PubMed Central

Kim, Youngwoo; Ge, Yinghui; Tao, Cheng; Zhu, Jianbing; Chapman, Arlene B.; Torres, Vicente E.; Yu, Alan S.L.; Mrug, Michal; Bennett, William M.; Flessner, Michael F.; Landsittel, Doug P.

2016-01-01

Background and objectives Our study developed a fully automated method for segmentation and volumetric measurements of kidneys from magnetic resonance images in patients with autosomal dominant polycystic kidney disease and assessed the performance of the automated method with the reference manual segmentation method. Design, setting, participants, & measurements Study patients were selected from the Consortium for Radiologic Imaging Studies of Polycystic Kidney Disease. At the enrollment of the Consortium for Radiologic Imaging Studies of Polycystic Kidney Disease Study in 2000, patients with autosomal dominant polycystic kidney disease were between 15 and 46 years of age with relatively preserved GFRs. Our fully automated segmentation method was on the basis of a spatial prior probability map of the location of kidneys in abdominal magnetic resonance images and regional mapping with total variation regularization and propagated shape constraints that were formulated into a level set framework. T2–weighted magnetic resonance image sets of 120 kidneys were selected from 60 patients with autosomal dominant polycystic kidney disease and divided into the training and test datasets. The performance of the automated method in reference to the manual method was assessed by means of two metrics: Dice similarity coefficient and intraclass correlation coefficient of segmented kidney volume. The training and test sets were swapped for crossvalidation and reanalyzed. Results Successful segmentation of kidneys was performed with the automated method in all test patients. The segmented kidney volumes ranged from 177.2 to 2634 ml (mean, 885.4±569.7 ml). The mean Dice similarity coefficient ±SD between the automated and manual methods was 0.88±0.08. The mean correlation coefficient between the two segmentation methods for the segmented volume measurements was 0.97 (P<0.001 for each crossvalidation set). The results from the crossvalidation sets were highly comparable. Conclusions We have developed a fully automated method for segmentation of kidneys from abdominal magnetic resonance images in patients with autosomal dominant polycystic kidney disease with varying kidney volumes. The performance of the automated method was in good agreement with that of manual method. PMID:26797708

Solving multi-objective job shop scheduling problems using a non-dominated sorting genetic algorithm

NASA Astrophysics Data System (ADS)

Piroozfard, Hamed; Wong, Kuan Yew

2015-05-01

The efforts of finding optimal schedules for the job shop scheduling problems are highly important for many real-world industrial applications. In this paper, a multi-objective based job shop scheduling problem by simultaneously minimizing makespan and tardiness is taken into account. The problem is considered to be more complex due to the multiple business criteria that must be satisfied. To solve the problem more efficiently and to obtain a set of non-dominated solutions, a meta-heuristic based non-dominated sorting genetic algorithm is presented. In addition, task based representation is used for solution encoding, and tournament selection that is based on rank and crowding distance is applied for offspring selection. Swapping and insertion mutations are employed to increase diversity of population and to perform intensive search. To evaluate the modified non-dominated sorting genetic algorithm, a set of modified benchmarking job shop problems obtained from the OR-Library is used, and the results are considered based on the number of non-dominated solutions and quality of schedules obtained by the algorithm.

A short review of paleoenvironments for Lower Beaufort (Upper Permian) Karoo sequences from southern to central Africa: A major Gondwana Lacustrine episode

NASA Astrophysics Data System (ADS)

Yemane, K.; Kelts, K.

This paper compares Karoo deposits within the Lower Beaufort (Late Permian) time interval from southern to central Africa. Facies aspects are summarized for selected sequences and depositional environments assessed in connection with the palaeogeography. The comparison shows that thickness of Lower Beaufort sequences varies greatly; sequences are over a kilometre thick at the southern tip, but decrease drastically to the north, northwest and northeast, and is commonly absent from the western part of the subcontinent. Depositional environments are continental except for small estuarine intervals from a sequence in Tanzania. The commonest lithologies comprise mudstones, siltstones, arkoses and carbonates. In spite of the dominance of fluvial facies, the records preserved by intervals of lacustrine sequences suggest that large lakes were major features of the palaeogeography, and that lacustrine environments may have been dominant deposition environments. The Lower Beaufort landscape is generally interpreted as an expansive cratonic lowland with meandering rivers and streams crossing vast floodplains, which were indented by concomitant shallow lakes of various sizes. The lakes from the Karoo tectono-sedimentary terrain were often ephemeral and closely linked with fluvial processes, but large, anoxic lakers are also documented. On the other hand, giant, freshwater lakes, covered large areas of the Zambezian tectono-sedimentary terrain and may have been locally connected. Evidence from abundant freshwater fossil assemblages, particularly from the Zambezian tectono-sedimentary terrain suggest that in spite of the generally semi-arid global climate of the Upper Permian, seasonal precipitation (monsoonal?) supplied enough moisture to sustain large perennial lakes. Because of the unique nature of the Permian cotinental configuration and palaeogeography, however, modern analogues of large systems are lacking. The general lithological and palaeontological correlability of Lower Beaufort sequences suggests a similar regional palaeoclimate, whereas the differences in distribution are taken to be a result of control of tectonic settings. From the widespread occurrences of lake deposits in the African subcontinent, over relatively long interval, we conclude that lake deposits provide more information for a better understanding of Karoo palaeogeography than previously thought, since such lacustrine sequences should hold sensitive, high resolution records for palaeoenvironmental interpretations.

Importance of human right inferior frontoparietal network connected by inferior branch of superior longitudinal fasciculus tract in corporeal awareness of kinesthetic illusory movement.

PubMed

Amemiya, Kaoru; Naito, Eiichi

2016-05-01

It is generally believed that the human right cerebral hemisphere plays a dominant role in corporeal awareness, which is highly associated with conscious experience of the physical self. Prompted by our previous findings, we examined whether the right frontoparietal activations often observed when people experience kinesthetic illusory limb movement are supported by a large-scale brain network connected by a specific branch of the superior longitudinal fasciculus fiber tracts (SLF I, II, and III). We scanned brain activity with functional magnetic resonance imaging (MRI) while nineteen blindfolded healthy volunteers experienced illusory movement of the right stationary hand elicited by tendon vibration, which was replicated after the scanning. We also scanned brain activity when they executed and imagined right hand movement, and identified the active brain regions during illusion, execution, and imagery in relation to the SLF fiber tracts. We found that illusion predominantly activated the right inferior frontoparietal regions connected by SLF III, which were not substantially recruited during execution and imagery. Among these regions, activities in the right inferior parietal cortices and inferior frontal cortices showed right-side dominance and correlated well with the amount of illusion (kinesthetic illusory awareness) experienced by the participants. The results illustrated the predominant involvement of the right inferior frontoparietal network connected by SLF III when people recognize postural changes of their limb. We assume that the network bears a series of functions, specifically, monitoring the current status of the musculoskeletal system, and building-up and updating our postural model (body schema), which could be a basis for the conscious experience of the physical self. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

Do storage dynamics in hydropedological units control hydrological connectivity? (Invited)

NASA Astrophysics Data System (ADS)

Tetzlaff, D.; Birkel, C.; Dick, J.; Geris, J.; Soulsby, C.

2013-12-01

In many northern landscapes, peat-dominated riparian wetlands often characterise the zone of connection between terrestrial drainage and the river network. In order to understand the relationship between connectivity and stream flow generation in a montane headwater catchment, we examined the storage dynamics and isotopic composition of soil water in major hydropedological units. These formed a classic catena sequence for northern catchments from free-draining podzols on steep upper hillslopes through to peaty gleysols in lower receiving slopes to deeper peats (Histosols) in the riparian zone. The peaty gleys and peats remained saturated throughout the year, whilst the podzols showed distinct wetting and drying cycles. In this climatic region, most precipitation events are less than 10mm in magnitude, storm runoff is mainly generated from the Histosols and Gleysols, with runoff coefficients (RCs) typically <10%. In larger events the podzolic soils become strongly connected to the saturated areas and RCs can exceed 40%. Isotopic variations in precipitation are significantly damped in the organic-rich surface horizons of the soils due to mixing with larger volumes of stored water. This damping is accentuated in the deeper soil profile and groundwater. Consequently, the isotopic composition of stream water is also damped, but the strongly reflects that of the near surface waters in the riparian peats. Old 'pre-event' water generally accounts for >80% of flow, even in large events, mainly reflecting the displacement of water stored in the riparian peats and peaty gleys. These riparian areas appear to be the dominant zone where different catchment source waters mix; acting as an 'isostat' that regulates the isotopic composition of stream waters and integrates the Transit Time Distribution (TTD) for the catchment.

The Debate on Dominant Culture and Cultural Imperialism

ERIC Educational Resources Information Center

Anchan, John P.

2012-01-01

In this commentary, the author reviews in depth Roland S. Persson's (2012a) target article. According to him Persson (2012a) presents a convincing argument as he wove through examples and explanations. The idea of superculture connects well with the established neocolonial literature and the North-South/Centre-Periphery debate. From general to…

Does Calculation or Word-Problem Instruction Provide a Stronger Route to Prealgebraic Knowledge?

ERIC Educational Resources Information Center

Fuchs, Lynn S.; Powell, Sarah R.; Cirino, Paul T.; Schumacher, Robin F.; Marrin, Sarah; Hamlett, Carol L.; Fuchs, Douglas; Compton, Donald L.; Changas, Paul C.

2014-01-01

The focus of this study was connections among 3 aspects of mathematical cognition at 2nd grade: calculations, word problems, and prealgebraic knowledge. We extended the literature, which is dominated by correlational work, by examining whether intervention conducted on calculations or word problems contributes to improved performance in the other…

Skepticism, Truth as Coherence, and Constructivist Epistemology: Grounds for Resolving the Discord between Science and Religion?

ERIC Educational Resources Information Center

Staver, John R.

2010-01-01

Science and religion exhibit multiple relationships as ways of knowing. These connections have been characterized as cousinly, mutually respectful, non-overlapping, competitive, proximate-ultimate, dominant-subordinate, and opposing-conflicting. Some of these ties create stress, and tension between science and religion represents a significant…

Hannah Arendt & Jean Baudrillard: Pedagogy in the Consumer Society

ERIC Educational Resources Information Center

Norris, Trevor

2006-01-01

This paper considers the place of education within our "consumers' society", beginning with Hannah Arendt's account of the rise of consumerism to a position of political dominance and the resulting eclipse of public life. Connections are then made between Arendt's account of this rise and Jean Baudrillard's account of the postmodern proliferation…

Reviving Forgotten Connections in North American Teacher Education: Klaus Mollenhauer and the Pedagogical Relation

ERIC Educational Resources Information Center

Friesen, Norm; Saevi, Tone

2010-01-01

Despite the dominance of instrumental, psychological approaches to educational theory and practice in North America, a different understanding of the value and dynamics of education is often articulated informally in cultural representations (e.g. fiction and feature films) and in personal recollections. This alternative understanding is one in…

Living waters: Connection and separation in water from physical, legal, political, and spiritual perspectives

EPA Science Inventory

Water is a dominant material on the Earth’s surface, covering most of the planet. Water significantly shapes land through the hydrologic cycle. Water is essential to all life, and plays critical roles in human society. In this talk, we will examine water from physical, legal, ...

The Educational and Psychological Interventions for Children and Adolescents with Marfan Syndrome.

ERIC Educational Resources Information Center

Stebbins, Molly S.; McIntosh, David E.

Marfan's syndrome is an autosomal dominant chromosomal disorder of connective tissue which may cause major abnormalities in the musculoskeletal, ocular (pertaining to the eye), and cardiovascular systems of the body. A description of this disorder is presented in this paper. It affects approximately .03 to .05% of the population; approximately…

Creating Anytime, Anywhere Learning for All Students: Key Elements of a Comprehensive Digital Infrastructure

ERIC Educational Resources Information Center

Thigpen, Kamila

2014-01-01

While connecting the nation's schools and libraries to the internet by modernizing and expanding the federal E-rate program currently dominates education technology efforts, a new report from the Alliance for Excellent Education urges that adequate broadband access be accompanied by a comprehensive "digital infrastructure" that unlocks…

Sexual Uncertainties and Disabled Young Men: Silencing Difference within the Classroom

ERIC Educational Resources Information Center

Blyth, Craig; Carson, Iain

2007-01-01

This paper reflects upon and connects the findings of two research projects that examined the sexual inequalities experienced by disabled young gay men. Using some of the data for illustrative purposes, we explore the consequences of the dominant heteronormative discursive practices that they experienced within sex education classes. Drawing on…

"Chinese-Mexicans" and "Blackest Asians": Filipino American Youth Resisting the Racial Binary

ERIC Educational Resources Information Center

Chutuape, Erica D.

2016-01-01

This study provides a deeper understanding of the interracial connections not just between non-whites and whites, but among non-whites. Filipino American youth attending high school in New York City contended with a dominant bipolar racial discourse that marginalizes the racialized experiences of Asians and Pacific Islanders. However, instead of…

Learning and Engagement in the Local Food Movement

ERIC Educational Resources Information Center

Bailey-Davis, Lisa

2013-01-01

The local food movement relates to the local food system that offers an alternative to the dominant industrialized food system. The hope of the local food movement is that through engagement with the local food system, participants will develop a deeper connection with the food beyond commodity perspectives, develop a social consciousness about…

Poverty, Literacy, and Social Transformation: An Interdisciplinary Exploration of the Digital Divide

ERIC Educational Resources Information Center

Bach, Amy J.; Wolfson, Todd; Crowell, Jessica K.

2018-01-01

Harnessing scholarship focused on literacy and poverty, in this article we aim to complicate the common understanding of the digital divide. First, we argue that the dominant literature on the digital divide misses broader connections between technological exclusion and broader forms of economic and social exclusion. Accordingly, and following…

An Overview of Parental Perceptions in Cross-Cultural Groups on Disability

ERIC Educational Resources Information Center

Diken, Ibrahim H.

2006-01-01

The role of culture in children's development and in early intervention/early childhood special education practices has been ignored in the United States until recent years (Coll & Magnuson, 2000), with the values of the Anglo American culture dominating. Among the cultural characteristics of families, parental perceptions in connection with…

Bathypelagic Food Web Structure of the Northern Atlantic Mid-Atlantic Ridge Based on Stable Isotope Analysis

EPA Science Inventory

The objective of our study was to characterize the trophic connections of the dominant fishes of the deep-pelagic region of the northern Mid-Atlantic Ridge (MAR) with respect to vertical distribution using carbon (C) and nitrogen (N) stable isotope analysis. Our goals were to id...

Education and Worker Co-operatives. Some Perspectives of the Australian TAFE Connection.

ERIC Educational Resources Information Center

Davis, Denis

The workers' cooperative movement has grown in many countries of Europe, where it is often state-sanctioned and supported. In Australia, however, the movement is just beginning. The government organization of what are called cooperative development programs is the dominant new feature on the Australian worker cooperative scene. However, funding is…

Bistability and up/down state alternations in inhibition-dominated randomly connected networks of LIF neurons.

PubMed

Tartaglia, Elisa M; Brunel, Nicolas

2017-09-20

Electrophysiological recordings in cortex in vivo have revealed a rich variety of dynamical regimes ranging from irregular asynchronous states to a diversity of synchronized states, depending on species, anesthesia, and external stimulation. The average population firing rate in these states is typically low. We study analytically and numerically a network of sparsely connected excitatory and inhibitory integrate-and-fire neurons in the inhibition-dominated, low firing rate regime. For sufficiently high values of the external input, the network exhibits an asynchronous low firing frequency state (L). Depending on synaptic time constants, we show that two scenarios may occur when external inputs are decreased: (1) the L state can destabilize through a Hopf bifucation as the external input is decreased, leading to synchronized oscillations spanning d δ to β frequencies; (2) the network can reach a bistable region, between the low firing frequency network state (L) and a quiescent one (Q). Adding an adaptation current to excitatory neurons leads to spontaneous alternations between L and Q states, similar to experimental observations on UP and DOWN states alternations.

Decomposability and convex structure of thermal processes

NASA Astrophysics Data System (ADS)

Mazurek, Paweł; Horodecki, Michał

2018-05-01

We present an example of a thermal process (TP) for a system of d energy levels, which cannot be performed without an instant access to the whole energy space. This TP is uniquely connected with a transition between some states of the system, that cannot be performed without access to the whole energy space even when approximate transitions are allowed. Pursuing the question about the decomposability of TPs into convex combinations of compositions of processes acting non-trivially on smaller subspaces, we investigate transitions within the subspace of states diagonal in the energy basis. For three level systems, we determine the set of extremal points of these operations, as well as the minimal set of operations needed to perform an arbitrary TP, and connect the set of TPs with thermomajorization criterion. We show that the structure of the set depends on temperature, which is associated with the fact that TPs cannot increase deterministically extractable work from a state—the conclusion that holds for arbitrary d level system. We also connect the decomposability problem with detailed balance symmetry of an extremal TPs.

Network Sampling and Classification:An Investigation of Network Model Representations

PubMed Central

Airoldi, Edoardo M.; Bai, Xue; Carley, Kathleen M.

2011-01-01

Methods for generating a random sample of networks with desired properties are important tools for the analysis of social, biological, and information networks. Algorithm-based approaches to sampling networks have received a great deal of attention in recent literature. Most of these algorithms are based on simple intuitions that associate the full features of connectivity patterns with specific values of only one or two network metrics. Substantive conclusions are crucially dependent on this association holding true. However, the extent to which this simple intuition holds true is not yet known. In this paper, we examine the association between the connectivity patterns that a network sampling algorithm aims to generate and the connectivity patterns of the generated networks, measured by an existing set of popular network metrics. We find that different network sampling algorithms can yield networks with similar connectivity patterns. We also find that the alternative algorithms for the same connectivity pattern can yield networks with different connectivity patterns. We argue that conclusions based on simulated network studies must focus on the full features of the connectivity patterns of a network instead of on the limited set of network metrics for a specific network type. This fact has important implications for network data analysis: for instance, implications related to the way significance is currently assessed. PMID:21666773

Improvement of white matter and functional connectivity abnormalities by repetitive transcranial magnetic stimulation in crossed aphasia in dextral.

PubMed

Lu, Haitao; Wu, Haiyan; Cheng, Hewei; Wei, Dongjie; Wang, Xiaoyan; Fan, Yong; Zhang, Hao; Zhang, Tong

2014-01-01

As a special aphasia, the occurrence of crossed aphasia in dextral (CAD) is unusual. This study aims to improve the language ability by applying 1 Hz repetitive transcranial magnetic stimulation (rTMS). We studied multiple modality imaging of structural connectivity (diffusion tensor imaging), functional connectivity (resting fMRI), PET, and neurolinguistic analysis on a patient with CAD. Furthermore, we applied rTMS of 1 Hz for 40 times and observed the language function improvement. The results indicated that a significantly reduced structural and function connectivity was found in DTI and fMRI data compared with the control. The PET imaging showed hypo-metabolism in right hemisphere and left cerebellum. In conclusion, one of the mechanisms of CAD is that right hemisphere is the language dominance. Stimulating left Wernicke area could improve auditory comprehension, stimulating left Broca's area could enhance expression, and the results outlasted 6 months by 1 Hz rTMS balancing the excitability inter-hemisphere in CAD.

Four-state rock-paper-scissors games in constrained Newman-Watts networks.

PubMed

Zhang, Guo-Yong; Chen, Yong; Qi, Wei-Kai; Qing, Shao-Meng

2009-06-01

We study the cyclic dominance of three species in two-dimensional constrained Newman-Watts networks with a four-state variant of the rock-paper-scissors game. By limiting the maximal connection distance Rmax in Newman-Watts networks with the long-range connection probability p , we depict more realistically the stochastic interactions among species within ecosystems. When we fix mobility and vary the value of p or Rmax, the Monte Carlo simulations show that the spiral waves grow in size, and the system becomes unstable and biodiversity is lost with increasing p or Rmax. These results are similar to recent results of Reichenbach et al. [Nature (London) 448, 1046 (2007)], in which they increase the mobility only without including long-range interactions. We compared extinctions with or without long-range connections and computed spatial correlation functions and correlation length. We conclude that long-range connections could improve the mobility of species, drastically changing their crossover to extinction and making the system more unstable.

A Composite Network Approach for Assessing Multi-Species Connectivity: An Application to Road Defragmentation Prioritisation

PubMed Central

Saura, Santiago; Rondinini, Carlo

2016-01-01

One of the biggest challenges in large-scale conservation is quantifying connectivity at broad geographic scales and for a large set of species. Because connectivity analyses can be computationally intensive, and the planning process quite complex when multiple taxa are involved, assessing connectivity at large spatial extents for many species turns to be often intractable. Such limitation results in that conducted assessments are often partial by focusing on a few key species only, or are generic by considering a range of dispersal distances and a fixed set of areas to connect that are not directly linked to the actual spatial distribution or mobility of particular species. By using a graph theory framework, here we propose an approach to reduce computational effort and effectively consider large assemblages of species in obtaining multi-species connectivity priorities. We demonstrate the potential of the approach by identifying defragmentation priorities in the Italian road network focusing on medium and large terrestrial mammals. We show that by combining probabilistic species graphs prior to conducting the network analysis (i) it is possible to analyse connectivity once for all species simultaneously, obtaining conservation or restoration priorities that apply for the entire species assemblage; and that (ii) those priorities are well aligned with the ones that would be obtained by aggregating the results of separate connectivity analysis for each of the individual species. This approach offers great opportunities to extend connectivity assessments to large assemblages of species and broad geographic scales. PMID:27768718

Node-based measures of connectivity in genetic networks.

PubMed

Koen, Erin L; Bowman, Jeff; Wilson, Paul J

2016-01-01

At-site environmental conditions can have strong influences on genetic connectivity, and in particular on the immigration and settlement phases of dispersal. However, at-site processes are rarely explored in landscape genetic analyses. Networks can facilitate the study of at-site processes, where network nodes are used to model site-level effects. We used simulated genetic networks to compare and contrast the performance of 7 node-based (as opposed to edge-based) genetic connectivity metrics. We simulated increasing node connectivity by varying migration in two ways: we increased the number of migrants moving between a focal node and a set number of recipient nodes, and we increased the number of recipient nodes receiving a set number of migrants. We found that two metrics in particular, the average edge weight and the average inverse edge weight, varied linearly with simulated connectivity. Conversely, node degree was not a good measure of connectivity. We demonstrated the use of average inverse edge weight to describe the influence of at-site habitat characteristics on genetic connectivity of 653 American martens (Martes americana) in Ontario, Canada. We found that highly connected nodes had high habitat quality for marten (deep snow and high proportions of coniferous and mature forest) and were farther from the range edge. We recommend the use of node-based genetic connectivity metrics, in particular, average edge weight or average inverse edge weight, to model the influences of at-site habitat conditions on the immigration and settlement phases of dispersal. © 2015 John Wiley & Sons Ltd.

Markov models for fMRI correlation structure: Is brain functional connectivity small world, or decomposable into networks?

PubMed

Varoquaux, G; Gramfort, A; Poline, J B; Thirion, B

2012-01-01

Correlations in the signal observed via functional Magnetic Resonance Imaging (fMRI), are expected to reveal the interactions in the underlying neural populations through hemodynamic response. In particular, they highlight distributed set of mutually correlated regions that correspond to brain networks related to different cognitive functions. Yet graph-theoretical studies of neural connections give a different picture: that of a highly integrated system with small-world properties: local clustering but with short pathways across the complete structure. We examine the conditional independence properties of the fMRI signal, i.e. its Markov structure, to find realistic assumptions on the connectivity structure that are required to explain the observed functional connectivity. In particular we seek a decomposition of the Markov structure into segregated functional networks using decomposable graphs: a set of strongly-connected and partially overlapping cliques. We introduce a new method to efficiently extract such cliques on a large, strongly-connected graph. We compare methods learning different graph structures from functional connectivity by testing the goodness of fit of the model they learn on new data. We find that summarizing the structure as strongly-connected networks can give a good description only for very large and overlapping networks. These results highlight that Markov models are good tools to identify the structure of brain connectivity from fMRI signals, but for this purpose they must reflect the small-world properties of the underlying neural systems. Copyright © 2012 Elsevier Ltd. All rights reserved.

Influence of urban form on landscape pattern and connectivity in metropolitan regions: a comparative case study of Phoenix, AZ, USA, and Izmir, Turkey.

PubMed

Park, Sohyun; Hepcan, Çiğdem C; Hepcan, Şerif; Cook, Edward A

2014-10-01

Although ecological connectivity conservation in urban areas has recently been recognized as an important issue, less is known about its relationship to urban form and landscape pattern. This study investigates how urban morphology influences regional ecosystem pattern and landscape connectivity. Two metropolitan landscapes, Phoenix, AZ, USA, and Izmir, Turkey, were compared, both of which are fast-growing regions in their national context. A wide range of variables were considered for identifying natural and urban properties. The natural characteristics include typology of urban ecosystems, urban to natural cover ratio, dominant habitat type, urban biodiversity, landscape context, and connectivity conservation efforts. Urban parameters examine urban form, urban extent, urban cover proportion, growth rate, populations, urban gradient, major drivers of urbanization, urban density, and mode/approach of urban development. Twelve landscape metrics were measured and compared across the natural patches. Results show that there is little difference in landscape connectivity in the rural zones of Phoenix and Izmir, although Phoenix has slightly higher connectivity values. The connectivity variance in urbanized areas, however, is significantly dependent on the region. For example, Phoenix urban zones have substantially lower connectivity than either urban or suburban zones in Izmir. Findings demonstrate that small and compact urban settlements with more dense populations are more likely to conserve landscape connectivity compared to multiple-concentric but amalgamated urban form spreading all over the landscape (aka urban sprawl).

Kähler-driven tribrid inflation

NASA Astrophysics Data System (ADS)

Antusch, Stefan; Nolde, David

2012-11-01

We discuss a new class of tribrid inflation models in supergravity, where the shape of the inflaton potential is dominated by effects from the Kähler potential. Tribrid inflation is a variant of hybrid inflation which is particularly suited for connecting inflation with particle physics, since the inflaton can be a D-flat combination of charged fields from the matter sector. In models of tribrid inflation studied so far, the inflaton potential was dominated by either loop corrections or by mixing effects with the waterfall field (as in "pseudosmooth" tribrid inflation). Here we investigate the third possibility, namely that tribrid inflation is dominantly driven by effects from higher-dimensional operators of the Kähler potential. We specify for which superpotential parameters the new regime is realized and show how it can be experimentally distinguished from the other two (loop-driven and "pseudosmooth") regimes.

Theory for the alignment of cortical feature maps during development.

PubMed

Bressloff, Paul C; Oster, Andrew M

2010-08-01

We present a developmental model of ocular dominance column formation that takes into account the existence of an array of intrinsically specified cytochrome oxidase blobs. We assume that there is some molecular substrate for the blobs early in development, which generates a spatially periodic modulation of experience-dependent plasticity. We determine the effects of such a modulation on a competitive Hebbian mechanism for the modification of the feedforward afferents from the left and right eyes. We show how alternating left and right eye dominated columns can develop, in which the blobs are aligned with the centers of the ocular dominance columns and receive a greater density of feedforward connections, thus becoming defined extrinsically. More generally, our results suggest that the presence of periodically distributed anatomical markers early in development could provide a mechanism for the alignment of cortical feature maps.

Using of porous portion to simulate pulmonary resistance in the computational fluid dynamic models of Fontan connection.

PubMed

Sun, Qi; Liu, Jinlong; Qian, Yi; Hong, Haifa; Liu, Jinfen

2013-01-01

In this study, we performed computational fluid dynamic (CFD) simulations in a patient-specific three-dimensional extracardiac conduit Fontan connection. The pulmonary resistance was incorporated in the CFD model by connecting porous portions in the left and right pulmonary arteries. The pressure in the common atrium was set as boundary conditions at the outlets of the pulmonary arteries. The flow rate in the innominate veins and the inferior vena cava (IVC) was set as inflow boundary conditions. Furthermore, the inflow rate of IVC was increased to 2 and 3 times of that measured to perform another two simulations and the resistance provided by the porous portions was compared among these three conditions. We found out that the pulmonary resistance set as porous portion in the CFD models remains relatively steady despite the change of the inflow rate. We concluded that, in the CFD simulations for the Fontan connections, porous portion could be used to represent pulmonary resistance steadily. The pulmonary resistance and pressure in the common atrium could be acquired directly by clinical examination. The employment of porous portion together with pressure in the common atrium in the CFD model could facilitate and accurate the set of outlet boundary conditions especially for those actual pulmonary flow splits was unpredictable such as virtual operative designs related CFD simulations.

Connectivity in modelling subsurface stormflow and tracer transport in a forested hillslope

NASA Astrophysics Data System (ADS)

Laine-Kaulio, Hanne; Koivusalo, Harri

2016-04-01

Preferential flow characterizes subsurface water movement in forested hillslopes. Connectivity of preferential flowpaths in soil, as well as connections between the preferential flowpaths and the soil matrix, control the flow patterns in hillslopes. We simulated subsurface stormflow and tracer transport within a forested hillslope section in Eastern Finland with a modifiable and detailed, physically-based 3-D dual-permeability model. The objective was to investigate the role of flowpath connectivity in capturing the observed migration velocity and concentration status of a tracer plume during the different stages of an irrigation experiment. Hypotheses to explain the observed transport behaviour were formulated based on observed spatial variations in the soil properties. The hypotheses were then tested by running corresponding model versions against spatial high-frequency data from the irrigation experiment. The 3-D distribution of preferential flowpaths, and the connections and disconnections between them, had the most crucial role in capturing the observed transport event with the model. Lateral by-pass flow in the preferential flow network and the transmissivity feedback phenomenon dominated the tracer transport. However, disconnections in lateral preferential flow restrained the transport, making the transport route devious instead of being directly lateral. These disconnections were caused by spots of cemented soil material. Stones had an opposite effect on the flow route formation compared to the cemented spots because preferential flowpaths were present on stone surfaces. Preferential flowpaths related to stones were linked with other types of preferential flowpaths in soil, facilitating the connectivity of preferential flowpaths within the entire hillslope. To take into account the discontinuity in lateral preferential flow and the tortuosity of the dominant flow routes in the model, an explicit representation of the 3-D distribution of saturated hydraulic conductivity in the preferential flow network was required. In addition, with-depth changing porosity values of both pore domains of soil, i.e., the preferential flowpaths and the soil matrix, as well as explicit descriptions of local water losses into the underlying bedrock, were found important for successful simulations. Other investigated model features, including complexity in the values of the rest of the model parameters and in the calculation routines used in describing the flow connections between the preferential flowpaths and the soil matrix, were not found beneficial for the model outcome.

Dynamic Braking System of a Tidal Generator: Preprint

DOE Office of Scientific and Technical Information (OSTI.GOV)

Muljadi, Eduard; Wright, Alan; Gevorgian, Vahan

Renewable energy generation has experienced significant cost reductions during the past decades, and it has become more accepted by the global population. In the beginning, wind generation dominated the development and deployment of renewable energy; however, during recent decades, photovoltaic (PV) generation has grown at a very significant pace due to the tremendous decrease in the cost of PV modules. The focus on renewable energy generation has now expanded to include new types with promising future applications, such as river and tidal generation. The input water flow to these types of resources is more predictable than wind or solar generation.more » The data used in this paper is representative of a typical river or tidal generator. The analysis is based on a generator with a power rating of 40 kW. The tidal generator under consideration is driven by two sets of helical turbines connected to each side of the generator located in between the turbines. The generator is operated in variable speed, and it is controlled to maximize the energy harvested as well as the operation of the turbine generator. The electrical system consists of a three-phase permanent magnet generator connected to a three-phase passive rectifier. The output of the rectifier is connected to a DC-DC converter to match the rectifier output to the DC bus voltage of the DC-AC inverter. The three-phase inverter is connected to the grid, and it is controlled to provide a good interface with the grid. One important aspect of river and tidal generation is the braking mechanism. In a tidal generator, the braking mechanism is important to avoid a runaway condition in case the connection to the grid is lost when there is a fault in the lines. A runaway condition may lead to an overspeed condition and cause extreme stresses on the turbine blade structure and eventual disintegration of the mechanical structure. In this paper, the concept of the dynamic braking system is developed and investigated for normal and abnormal operations. The main objective is to optimize the performance under emergency braking while designing the system to be as simple as possible to avoid overdesigning the power electronics or exceeding the target budget.« less

Brain properties predict proximity to symptom onset in sporadic Alzheimer’s disease

PubMed Central

Vogel, Jacob W; Vachon-Presseau, Etienne; Pichet Binette, Alexa; Tam, Angela; Orban, Pierre; La Joie, Renaud; Savard, Mélissa; Picard, Cynthia; Poirier, Judes; Bellec, Pierre; Breitner, John C S; Villeneuve, Sylvia

2018-01-01

Abstract See Tijms and Visser (doi:10.1093/brain/awy113) for a scientific commentary on this article. Alzheimer’s disease is preceded by a lengthy ‘preclinical’ stage spanning many years, during which subtle brain changes occur in the absence of overt cognitive symptoms. Predicting when the onset of disease symptoms will occur is an unsolved challenge in individuals with sporadic Alzheimer’s disease. In individuals with autosomal dominant genetic Alzheimer’s disease, the age of symptom onset is similar across generations, allowing the prediction of individual onset times with some accuracy. We extend this concept to persons with a parental history of sporadic Alzheimer’s disease to test whether an individual’s symptom onset age can be informed by the onset age of their affected parent, and whether this estimated onset age can be predicted using only MRI. Structural and functional MRIs were acquired from 255 ageing cognitively healthy subjects with a parental history of sporadic Alzheimer’s disease from the PREVENT-AD cohort. Years to estimated symptom onset was calculated as participant age minus age of parental symptom onset. Grey matter volume was extracted from T1-weighted images and whole-brain resting state functional connectivity was evaluated using degree count. Both modalities were summarized using a 444-region cortical-subcortical atlas. The entire sample was divided into training (n = 138) and testing (n = 68) sets. Within the training set, individuals closer to or beyond their parent’s symptom onset demonstrated reduced grey matter volume and altered functional connectivity, specifically in regions known to be vulnerable in Alzheimer’s disease. Machine learning was used to identify a weighted set of imaging features trained to predict years to estimated symptom onset. This feature set alone significantly predicted years to estimated symptom onset in the unseen testing data. This model, using only neuroimaging features, significantly outperformed a similar model instead trained with cognitive, genetic, imaging and demographic features used in a traditional clinical setting. We next tested if these brain properties could be generalized to predict time to clinical progression in a subgroup of 26 individuals from the Alzheimer’s Disease Neuroimaging Initiative, who eventually converted either to mild cognitive impairment or to Alzheimer’s dementia. The feature set trained on years to estimated symptom onset in the PREVENT-AD predicted variance in time to clinical conversion in this separate longitudinal dataset. Adjusting for participant age did not impact any of the results. These findings demonstrate that years to estimated symptom onset or similar measures can be predicted from brain features and may help estimate presymptomatic disease progression in at-risk individuals. PMID:29688388

Connected Education: Teachers' Attitudes towards Student Learning in a 1:1 Technology Middle School Environment

ERIC Educational Resources Information Center

Luo, Tian; Murray, Alexander

2018-01-01

Online and blended forms of learning has been increasingly common in K-12 settings, along with the technological advancement with always-on and connected devices. The study purports to understand teachers' attitudes towards the middle school's one-laptop-per-student (1:1) policy and students' frequent use of always-on and connected technology, as…

Apple OS X VPN Set Up | High-Performance Computing | NREL

Science.gov Websites

software using that conf file and your UserID Start the connection using your password plus the 6-digit OTP . Configure the Client Software Start the Endian Connect App (It should have installed into Applications in an password" link, and add your UserID. Start the app, and begin configuring the connection by clicking

The physical foundation of the reconnection electric field

NASA Astrophysics Data System (ADS)

Hesse, M.; Liu, Y.-H.; Chen, L.-J.; Bessho, N.; Wang, S.; Burch, J. L.; Moretto, T.; Norgren, C.; Genestreti, K. J.; Phan, T. D.; Tenfjord, P.

2018-03-01

Magnetic reconnection is a key charged particle transport and energy conversion process in environments ranging from astrophysical systems to laboratory plasmas [Yamada et al., Rev. Mod. Phys. 82, 603-664 (2010)]. Magnetic reconnection facilitates plasma transport by establishing new connections of magnetic flux tubes, and it converts, often explosively, energy stored in the magnetic field to kinetic energy of charged particles [J. L. Burch and J. F. Drake, Am. Sci. 97, 392-299 (2009)]. The intensity of the magnetic reconnection process is measured by the reconnection electric field, which regulates the rate of flux tube connectivity changes. The change of magnetic connectivity occurs in the current layer of the diffusion zone, where the plasma transport is decoupled from the transport of magnetic flux. Here we report on computer simulations and analytic theory to provide a self-consistent understanding of the role of the reconnection electric field, which extends substantially beyond the simple change of magnetic connections. Rather, we find that the reconnection electric field is essential to maintain the current density in the diffusion region, which would otherwise be dissipated by a set of processes. Natural candidates for current dissipation are the average convection of current carriers away from the reconnection region by the outflow of accelerated particles, or the average rotation of the current density by the magnetic field reversal in the vicinity. Instead, we show here that the current dissipation is the result of thermal effects, underlying the statistical interaction of current-carrying particles with the adjacent magnetic field. We find that this interaction serves to redirect the directed acceleration of the reconnection electric field to thermal motion. This thermalization manifests itself in form of quasi-viscous terms in the thermal energy balance of the current layer. This collisionless viscosity, found in the pressure evolution equation, dominates near the x-line. These quasi-viscous terms act to increase the average thermal energy. Our predictions regarding current and thermal energy balance are readily amenable to exploration in the laboratory or by satellite missions, in particular, by NASA's Magnetospheric Multiscale mission.

A Multi-Hop Clustering Mechanism for Scalable IoT Networks.

PubMed

Sung, Yoonyoung; Lee, Sookyoung; Lee, Meejeong

2018-03-23

It is expected that up to 26 billion Internet of Things (IoT) equipped with sensors and wireless communication capabilities will be connected to the Internet by 2020 for various purposes. With a large scale IoT network, having each node connected to the Internet with an individual connection may face serious scalability issues. The scalability problem of the IoT network may be alleviated by grouping the nodes of the IoT network into clusters and having a representative node in each cluster connect to the Internet on behalf of the other nodes in the cluster instead of having a per-node Internet connection and communication. In this paper, we propose a multi-hop clustering mechanism for IoT networks to minimize the number of required Internet connections. Specifically, the objective of proposed mechanism is to select the minimum number of coordinators, which take the role of a representative node for the cluster, i.e., having the Internet connection on behalf of the rest of the nodes in the cluster and to map a partition of the IoT nodes onto the selected set of coordinators to minimize the total distance between the nodes and their respective coordinator under a certain constraint in terms of maximum hop count between the IoT nodes and their respective coordinator. Since this problem can be mapped into a set cover problem which is known as NP-hard, we pursue a heuristic approach to solve the problem and analyze the complexity of the proposed solution. Through a set of experiments with varying parameters, the proposed scheme shows 63-87.3% reduction of the Internet connections depending on the number of the IoT nodes while that of the optimal solution is 65.6-89.9% in a small scale network. Moreover, it is shown that the performance characteristics of the proposed mechanism coincide with expected performance characteristics of the optimal solution in a large-scale network.

A Multi-Hop Clustering Mechanism for Scalable IoT Networks

PubMed Central

2018-01-01

It is expected that up to 26 billion Internet of Things (IoT) equipped with sensors and wireless communication capabilities will be connected to the Internet by 2020 for various purposes. With a large scale IoT network, having each node connected to the Internet with an individual connection may face serious scalability issues. The scalability problem of the IoT network may be alleviated by grouping the nodes of the IoT network into clusters and having a representative node in each cluster connect to the Internet on behalf of the other nodes in the cluster instead of having a per-node Internet connection and communication. In this paper, we propose a multi-hop clustering mechanism for IoT networks to minimize the number of required Internet connections. Specifically, the objective of proposed mechanism is to select the minimum number of coordinators, which take the role of a representative node for the cluster, i.e., having the Internet connection on behalf of the rest of the nodes in the cluster and to map a partition of the IoT nodes onto the selected set of coordinators to minimize the total distance between the nodes and their respective coordinator under a certain constraint in terms of maximum hop count between the IoT nodes and their respective coordinator. Since this problem can be mapped into a set cover problem which is known as NP-hard, we pursue a heuristic approach to solve the problem and analyze the complexity of the proposed solution. Through a set of experiments with varying parameters, the proposed scheme shows 63–87.3% reduction of the Internet connections depending on the number of the IoT nodes while that of the optimal solution is 65.6–89.9% in a small scale network. Moreover, it is shown that the performance characteristics of the proposed mechanism coincide with expected performance characteristics of the optimal solution in a large-scale network. PMID:29570691

MIP models for connected facility location: A theoretical and computational study☆

PubMed Central

Gollowitzer, Stefan; Ljubić, Ivana

2011-01-01

This article comprises the first theoretical and computational study on mixed integer programming (MIP) models for the connected facility location problem (ConFL). ConFL combines facility location and Steiner trees: given a set of customers, a set of potential facility locations and some inter-connection nodes, ConFL searches for the minimum-cost way of assigning each customer to exactly one open facility, and connecting the open facilities via a Steiner tree. The costs needed for building the Steiner tree, facility opening costs and the assignment costs need to be minimized. We model ConFL using seven compact and three mixed integer programming formulations of exponential size. We also show how to transform ConFL into the Steiner arborescence problem. A full hierarchy between the models is provided. For two exponential size models we develop a branch-and-cut algorithm. An extensive computational study is based on two benchmark sets of randomly generated instances with up to 1300 nodes and 115,000 edges. We empirically compare the presented models with respect to the quality of obtained bounds and the corresponding running time. We report optimal values for all but 16 instances for which the obtained gaps are below 0.6%. PMID:25009366

Enhanced economic connectivity to foster heat stress-related losses.

PubMed

Wenz, Leonie; Levermann, Anders

2016-06-01

Assessing global impacts of unexpected meteorological events in an increasingly connected world economy is important for estimating the costs of climate change. We show that since the beginning of the 21st century, the structural evolution of the global supply network has been such as to foster an increase of climate-related production losses. We compute first- and higher-order losses from heat stress-induced reductions in productivity under changing economic and climatic conditions between 1991 and 2011. Since 2001, the economic connectivity has augmented in such a way as to facilitate the cascading of production loss. The influence of this structural change has dominated over the effect of the comparably weak climate warming during this decade. Thus, particularly under future warming, the intensification of international trade has the potential to amplify climate losses if no adaptation measures are taken.

Broadband piezoelectric energy harvesting devices using multiple bimorphs with different operating frequencies.

PubMed

Xue, Huan; Hu, Yuantai; Wang, Qing-Ming

2008-09-01

This paper presents a novel approach for designing broadband piezoelectric harvesters by integrating multiple piezoelectric bimorphs (PBs) with different aspect ratios into a system. The effect of 2 connecting patterns among PBs, in series and in parallel, on improving energy harvesting performance is discussed. It is found for multifrequency spectra ambient vibrations: 1) the operating frequency band (OFB) of a harvesting structure can be widened by connecting multiple PBs with different aspect ratios in series; 2) the OFB of a harvesting structure can be shifted to the dominant frequency domain of the ambient vibrations by increasing or decreasing the number of PBs in parallel. Numerical results show that the OFB of the piezoelectric energy harvesting devices can be tailored by the connection patterns (i.e., in series and in parallel) among PBs.

Enhanced economic connectivity to foster heat stress–related losses

PubMed Central

Wenz, Leonie; Levermann, Anders

2016-01-01

Assessing global impacts of unexpected meteorological events in an increasingly connected world economy is important for estimating the costs of climate change. We show that since the beginning of the 21st century, the structural evolution of the global supply network has been such as to foster an increase of climate-related production losses. We compute first- and higher-order losses from heat stress–induced reductions in productivity under changing economic and climatic conditions between 1991 and 2011. Since 2001, the economic connectivity has augmented in such a way as to facilitate the cascading of production loss. The influence of this structural change has dominated over the effect of the comparably weak climate warming during this decade. Thus, particularly under future warming, the intensification of international trade has the potential to amplify climate losses if no adaptation measures are taken. PMID:27386555

Template based rotation: A method for functional connectivity analysis with a priori templates☆

PubMed Central

Schultz, Aaron P.; Chhatwal, Jasmeer P.; Huijbers, Willem; Hedden, Trey; van Dijk, Koene R.A.; McLaren, Donald G.; Ward, Andrew M.; Wigman, Sarah; Sperling, Reisa A.

2014-01-01

Functional connectivity magnetic resonance imaging (fcMRI) is a powerful tool for understanding the network level organization of the brain in research settings and is increasingly being used to study large-scale neuronal network degeneration in clinical trial settings. Presently, a variety of techniques, including seed-based correlation analysis and group independent components analysis (with either dual regression or back projection) are commonly employed to compute functional connectivity metrics. In the present report, we introduce template based rotation,1 a novel analytic approach optimized for use with a priori network parcellations, which may be particularly useful in clinical trial settings. Template based rotation was designed to leverage the stable spatial patterns of intrinsic connectivity derived from out-of-sample datasets by mapping data from novel sessions onto the previously defined a priori templates. We first demonstrate the feasibility of using previously defined a priori templates in connectivity analyses, and then compare the performance of template based rotation to seed based and dual regression methods by applying these analytic approaches to an fMRI dataset of normal young and elderly subjects. We observed that template based rotation and dual regression are approximately equivalent in detecting fcMRI differences between young and old subjects, demonstrating similar effect sizes for group differences and similar reliability metrics across 12 cortical networks. Both template based rotation and dual-regression demonstrated larger effect sizes and comparable reliabilities as compared to seed based correlation analysis, though all three methods yielded similar patterns of network differences. When performing inter-network and sub-network connectivity analyses, we observed that template based rotation offered greater flexibility, larger group differences, and more stable connectivity estimates as compared to dual regression and seed based analyses. This flexibility owes to the reduced spatial and temporal orthogonality constraints of template based rotation as compared to dual regression. These results suggest that template based rotation can provide a useful alternative to existing fcMRI analytic methods, particularly in clinical trial settings where predefined outcome measures and conserved network descriptions across groups are at a premium. PMID:25150630

A METHOD FOR USING BLOCKED AND EVENT-RELATED FMRI DATA TO STUDY “RESTING STATE” FUNCTIONAL CONNECTIVITY

PubMed Central

Fair, Damien A.; Schlaggar, Bradley L.; Cohen B.A., Alexander L.; Miezin, Francis M.; Dosenbach, Nico U.F.; Wenger, Kristin K.; Fox, Michael D.; Snyder, Abraham Z.; Raichle, Marcus E.; Petersen, Steven E.

2007-01-01

Resting state functional connectivity MRI (fcMRI) has become a particularly useful tool for studying regional relationships in typical and atypical populations. Because many investigators have already obtained large datasets of task related fMRI, the ability to use this existing task data for resting state fcMRI is of considerable interest. Two classes of datasets could potentially be modified to emulate resting state data. These datasets include: 1) “interleaved” resting blocks from blocked or mixed blocked/event-related sets, and 2) residual timecourses from event-related sets that lack rest blocks. Using correlation analysis, we compared the functional connectivity of resting epochs taken from a mixed blocked/event-related design fMRI data set and the residuals derived from event-related data with standard continuous resting state data to determine which class of data can best emulate resting state data. We show that despite some differences, the functional connectivity for the interleaved resting periods taken from blocked designs is both qualitatively and quantitatively very similar to that of “continuous” resting state data. In contrast, despite being qualitatively similar to “continuous” resting state data, residuals derived from event-related design data had several distinct quantitative differences. These results suggest that the interleaved resting state data such as those taken from blocked or mixed blocked/event-related fMRI designs are well-suited for resting state functional connectivity analyses. Although using event-related data residuals for resting state functional connectivity may still be useful, results should be interpreted with care. PMID:17239622

Accuracy in strategy imitations promotes the evolution of fairness in the spatial ultimatum game

NASA Astrophysics Data System (ADS)

Szolnoki, Attila; Perc, Matjaž; Szabó, György

2012-10-01

Spatial structure has a profound effect on the outcome of evolutionary games. In the ultimatum game, it leads to the dominance of much fairer players than those predicted to evolve in well-mixed settings. Here we show that spatiality leads to fair ultimatums only if the intervals from which the players are able to choose how much to offer and how little to accept are sufficiently fine-grained. Small sets of discrete strategies lead to the stable coexistence of the two most rational strategies in the set, while larger sets lead to the dominance of a single yet not necessarily the fairest strategy. The fairest outcome is obtained for the most accurate strategy imitation, that is in the limit of a continuous strategy set. Having a multitude of choices is thus crucial for the evolution of fairness, but not necessary for the evolution of empathy.

Connections in wood and foliage

Treesearch

Kevin T. Smith

2009-01-01

Trees are networked systems that capture energy, move massive amounts of water and material, and provide the setting for human society and for the lives of many associated organisms. Tree survival depends on making and breaking the right connections within these networks.

47 CFR 54.637 - Off-site data centers and off-site administrative offices.

Code of Federal Regulations, 2013 CFR

2013-10-01

... Healthcare Connect Fund § 54.637 Off-site data centers and off-site administrative offices. (a) The... the Healthcare Connect Fund, subject to the conditions and restrictions set forth in paragraph (b) of...

47 CFR 54.637 - Off-site data centers and off-site administrative offices.

Code of Federal Regulations, 2014 CFR

2014-10-01

... Healthcare Connect Fund § 54.637 Off-site data centers and off-site administrative offices. (a) The... the Healthcare Connect Fund, subject to the conditions and restrictions set forth in paragraph (b) of...

40 CFR 90.315 - Analyzer initial calibration.

Code of Federal Regulations, 2012 CFR

2012-07-01

... specifications in § 90.316(b). (c) Zero setting and calibration. Using purified synthetic air (or nitrogen), set the CO, CO2, NOX. and HC analyzers at zero. Connect the appropriate calibrating gases to the analyzers...) Rechecking of zero setting. Recheck the zero setting and, if necessary, repeat the procedure described in...

40 CFR 90.315 - Analyzer initial calibration.

Code of Federal Regulations, 2014 CFR

2014-07-01

... specifications in § 90.316(b). (c) Zero setting and calibration. Using purified synthetic air (or nitrogen), set the CO, CO2, NOX. and HC analyzers at zero. Connect the appropriate calibrating gases to the analyzers...) Rechecking of zero setting. Recheck the zero setting and, if necessary, repeat the procedure described in...

40 CFR 90.315 - Analyzer initial calibration.

Code of Federal Regulations, 2013 CFR

2013-07-01

... specifications in § 90.316(b). (c) Zero setting and calibration. Using purified synthetic air (or nitrogen), set the CO, CO2, NOX. and HC analyzers at zero. Connect the appropriate calibrating gases to the analyzers...) Rechecking of zero setting. Recheck the zero setting and, if necessary, repeat the procedure described in...

40 CFR 90.315 - Analyzer initial calibration.

Code of Federal Regulations, 2011 CFR

2011-07-01

... specifications in § 90.316(b). (c) Zero setting and calibration. Using purified synthetic air (or nitrogen), set the CO, CO2, NOX. and HC analyzers at zero. Connect the appropriate calibrating gases to the analyzers...) Rechecking of zero setting. Recheck the zero setting and, if necessary, repeat the procedure described in...

40 CFR 90.315 - Analyzer initial calibration.

Code of Federal Regulations, 2010 CFR

2010-07-01

... specifications in § 90.316(b). (c) Zero setting and calibration. Using purified synthetic air (or nitrogen), set the CO, CO2, NOX. and HC analyzers at zero. Connect the appropriate calibrating gases to the analyzers...) Rechecking of zero setting. Recheck the zero setting and, if necessary, repeat the procedure described in...

Requirements for soldered electrical connections

NASA Technical Reports Server (NTRS)

1992-01-01

This publication is applicable to NASA programs involving solder connections for flight hardware, mission essential support equipment, and elements thereof. This publication sets forth hand and wave soldering requirements for reliable electrical connections. The prime consideration is the physical integrity of solder connections. Special requirements may exist which are not in conformance with the requirements of this publication. Design documentation contains the detail for these requirements, and they take precedence over conflicting portions of this publication when they are approved in writing by the procuring NASA installation.

Geography-based structural analysis of the Internet

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kasiviswanathan, Shiva; Eidenbenz, Stephan; Yan, Guanhua

2010-01-01

In this paper, we study some geographic aspects of the Internet. We base our analysis on a large set of geolocated IP hop-level session data (including about 300,000 backbone routers, 150 million end hosts, and 1 billion sessions) that we synthesized from a variety of different input sources such as US census data, computer usage statistics, Internet market share data, IP geolocation data sets, CAJDA's Skitter data set for backbone connectivity, and BGP routing tables. We use this model to perform a nationwide and statewide geographic analysis of the Internet. Our main observations are: (1) There is a dominant coast-to-coastmore » pattern in the US Internet traffic. In fact, in many instances even if the end-devices are not near either coast, still the traffic between them takes a long detour through the coasts. (2) More than half of the Internet paths are inflated by 100% or more compared to their corresponding geometric straight-line distance. This circuitousness makes the average ratio between the routing distance and geometric distance big (around 10). (3) The weighted mean hop count is around 5, but the hop counts are very loosely correlated with the distances. The weighted mean AS count (number of ASes traversed) is around 3. (4) The AS size and the AS location number distributions are heavy-tailed and strongly correlated. Most of the ASes are medium sized and there is a wide variability in the geographic dispersion size (measured in terms of the convex hull area) of these ASes.« less

Comparative analysis of Pareto surfaces in multi-criteria IMRT planning

NASA Astrophysics Data System (ADS)

Teichert, K.; Süss, P.; Serna, J. I.; Monz, M.; Küfer, K. H.; Thieke, C.

2011-06-01

In the multi-criteria optimization approach to IMRT planning, a given dose distribution is evaluated by a number of convex objective functions that measure tumor coverage and sparing of the different organs at risk. Within this context optimizing the intensity profiles for any fixed set of beams yields a convex Pareto set in the objective space. However, if the number of beam directions and irradiation angles are included as free parameters in the formulation of the optimization problem, the resulting Pareto set becomes more intricate. In this work, a method is presented that allows for the comparison of two convex Pareto sets emerging from two distinct beam configuration choices. For the two competing beam settings, the non-dominated and the dominated points of the corresponding Pareto sets are identified and the distance between the two sets in the objective space is calculated and subsequently plotted. The obtained information enables the planner to decide if, for a given compromise, the current beam setup is optimal. He may then re-adjust his choice accordingly during navigation. The method is applied to an artificial case and two clinical head neck cases. In all cases no configuration is dominating its competitor over the whole Pareto set. For example, in one of the head neck cases a seven-beam configuration turns out to be superior to a nine-beam configuration if the highest priority is the sparing of the spinal cord. The presented method of comparing Pareto sets is not restricted to comparing different beam angle configurations, but will allow for more comprehensive comparisons of competing treatment techniques (e.g. photons versus protons) than with the classical method of comparing single treatment plans.

Brain effective connectivity during motor-imagery and execution following stroke and rehabilitation.

PubMed

Bajaj, Sahil; Butler, Andrew J; Drake, Daniel; Dhamala, Mukesh

2015-01-01

Brain areas within the motor system interact directly or indirectly during motor-imagery and motor-execution tasks. These interactions and their functionality can change following stroke and recovery. How brain network interactions reorganize and recover their functionality during recovery and treatment following stroke are not well understood. To contribute to answering these questions, we recorded blood oxygenation-level dependent (BOLD) functional magnetic resonance imaging (fMRI) signals from 10 stroke survivors and evaluated dynamical causal modeling (DCM)-based effective connectivity among three motor areas: primary motor cortex (M1), pre-motor cortex (PMC) and supplementary motor area (SMA), during motor-imagery and motor-execution tasks. We compared the connectivity between affected and unaffected hemispheres before and after mental practice and combined mental practice and physical therapy as treatments. The treatment (intervention) period varied in length between 14 to 51 days but all patients received the same dose of 60 h of treatment. Using Bayesian model selection (BMS) approach in the DCM approach, we found that, after intervention, the same network dominated during motor-imagery and motor-execution tasks but modulatory parameters suggested a suppressive influence of SM A on M1 during the motor-imagery task whereas the influence of SM A on M1 was unrestricted during the motor-execution task. We found that the intervention caused a reorganization of the network during both tasks for unaffected as well as for the affected hemisphere. Using Bayesian model averaging (BMA) approach, we found that the intervention improved the regional connectivity among the motor areas during both the tasks. The connectivity between PMC and M1 was stronger in motor-imagery tasks whereas the connectivity from PMC to M1, SM A to M1 dominated in motor-execution tasks. There was significant behavioral improvement (p = 0.001) in sensation and motor movements because of the intervention as reflected by behavioral Fugl-Meyer (FMA) measures, which were significantly correlated (p = 0.05) with a subset of connectivity. These findings suggest that PMC and M1 play a crucial role during motor-imagery as well as during motor-execution task. In addition, M1 causes more exchange of causal information among motor areas during a motor-execution task than during a motor-imagery task due to its interaction with SM A. This study expands our understanding of motor network involved during two different tasks, which are commonly used during rehabilitation following stroke. A clear understanding of the effective connectivity networks leads to a better treatment in helping stroke survivors regain motor ability.

Evaluating 'good governance': The development of a quantitative tool in the Greater Serengeti Ecosystem.

PubMed

Kisingo, Alex; Rollins, Rick; Murray, Grant; Dearden, Phil; Clarke, Marlea

2016-10-01

Protected areas (PAs) can provide important benefits to conservation and to communities. A key factor in the effective delivery of these benefits is the role of governance. There has been a growth in research developing frameworks to evaluate 'good' PA governance, usually drawing on a set of principles that are associated with groups of indicators. In contrast to dominant qualitative approaches, this paper describes the development of a quantitative method for measuring effectiveness of protected area governance, as perceived by stakeholders in the Greater Serengeti Ecosystem in Tanzania. The research developed a quantitative method for developing effectiveness measures of PA governance, using a set of 65 statements related to governance principles developed from a literature review. The instrument was administered to 389 individuals from communities located near PAs in the Greater Serengeti Ecosystem. The results of a factor analysis suggest that statements load onto 10 factors that demonstrate high psychometric validity as measured by factor loadings, explained variance, and Cronbach's alpha reliability. The ten common factors that were extracted were: 1) legitimacy, 2) transparency and accountability, 3) responsiveness, 4) fairness, 5) participation, 6) ecosystem based management (EBM) and connectivity, 7) resilience, 8) achievements, 9) consensus orientation, and 10) power. The paper concludes that quantitative surveys can be used to evaluate governance of protected areas from a community-level perspective. Copyright © 2016 Elsevier Ltd. All rights reserved.

Measuring the power consumption of social media applications on a mobile device

NASA Astrophysics Data System (ADS)

Dunia, A. I. M.; Suherman; Rambe, A. H.; Fauzi, R.

2018-03-01

As fully connected social media applications become popular and require all time connection, the power consumption on mobile device battery increases significantly. As power supplied by a battery is limited, social media application should be designed to be less power consuming. This paper reports the power consumption measurement of social media running on a mobile device. Experimental circuit was developed by using a microcontroller measuring an android smartphone on a 802.11 controlled network. The experiment results show that whatsapp consumes the power less than others in stand by and chat. While other states are dominated by line. The blackberry consumes the power the worst.

Ethnic syndromes as disguise for protest against colonialism: three ethnographic examples.

PubMed

Hegeman, Elizabeth

2013-01-01

Historical connections are suggested between the domination of 1 culture by another and dissociative spiritual and religious responses to that oppression. Connections are drawn between colonial oppression, trauma, and 3 examples of dissociation and spirit possession: the Zar cult of Southern Sudan, "Puerto Rican syndrome" or ataque, and the Balinese trance dance. Discussed by means of these examples are the role and functions of spirit possession as a means of escape from unbearable reality, where it becomes a form of the expression of needs and desires forbidden by authorities, a way of entering an identity not subject to traditional authorities, and reenactment of traumatic experience.

Elderly South Asian Canadian immigrant men: confirming and disrupting dominant discourses about masculinity and men's health.

PubMed

Oliffe, John L; Grewal, Suki; Bottorff, Joan L; Luke, Haida; Toor, Harshbir

2007-01-01

The experiences of elderly South Asian (SA) men who have immigrated to Canada provide unique insights to men's health and illness behaviors and beliefs. In this article, we describe the connections between masculinity, culture, and health among a cohort of 14 SA immigrant men. The findings indicated that participants' health behaviors were closely aligned to those of western men. However, a fine-grained analysis revealed how complex cultural connections informed and influenced many men's health behaviors and beliefs. Based on the study findings, recommendations for the future design of healthcare services targeted to SA men are made.

Dynamic analysis of a system of hinge-connected rigid bodies with nonrigid appendages. [equations of motion

NASA Technical Reports Server (NTRS)

Likins, P. W.

1974-01-01

Equations of motion are derived for use in simulating a spacecraft or other complex electromechanical system amenable to idealization as a set of hinge-connected rigid bodies of tree topology, with rigid axisymmetric rotors and nonrigid appendages attached to each rigid body in the set. In conjunction with a previously published report on finite-element appendage vibration equations, this report provides a complete minimum-dimension formulation suitable for generic programming for digital computer numerical integration.

Consumers, health insurance and dominated choices.

PubMed

Sinaiko, Anna D; Hirth, Richard A

2011-03-01

We analyze employee health plan choices when the choice set offered by their employer includes a dominated plan. During our study period, one-third of workers were enrolled in the dominated plan. Some may have selected the plan before it was dominated and then failed to switch out of it. However, a substantial number actively chose the dominated plan when they had an unambiguously better choice. These results suggest limitations in the ability of health reform based solely on consumer choice to achieve efficient outcomes and that implementation of health reform should anticipate, monitor and account for this consumer behavior. Copyright © 2011 Elsevier B.V. All rights reserved.

The Symbolic Violence of Setting: A Bourdieusian Analysis of Mixed Methods Data on Secondary Students' Views about Setting

ERIC Educational Resources Information Center

Archer, Louise; Francis, Becky; Miller, Sarah; Taylor, Becky; Tereshchenko, Antonina; Mazenod, Anna; Pepper, David; Travers, Mary-Claire

2018-01-01

"Setting" is a widespread practice in the UK, despite little evidence of its efficacy and substantial evidence of its detrimental impact on those allocated to the lowest sets. Taking a Bourdieusian approach, we propose that setting can be understood as a practice through which the social and cultural reproduction of dominant power…

Mina: a Th2 response regulator meets TGFβ.

PubMed

Pillai, Meenu R; Lian, Shangli; Bix, Mark

2014-12-01

The JmjC protein Mina is an important immune response regulator. Classical forward genetics first discovered its immune role in 2009 in connection with the development of T helper 2 (Th2) cells. This prompted investigation into Mina's role in the two best-studied contexts where Th2 responses are essential: atopic asthma and helminth expulsion. In work focused on a mouse model of atopic asthma, Mina deficiency was found to ameliorate airway hyper-resistance and pulmonary inflammation. And, in a case-control study genetic variation at the human MINA locus was found to be associated with the development of childhood atopic asthma. Although the underlying cellular and molecular mechanism of Mina's involvement in pulmonary inflammation remains unknown, our recent work on parasitic helminth expulsion suggests the possibility that, rather than T cells, epithelial cells responding to TGFβ may play the dominant role. Here we review the growing body of literature on the emerging Mina pathway in T cells and epithelial cells and attempt to set these into a broader context. Copyright © 2014 Elsevier Ltd. All rights reserved.

Interacting faults

NASA Astrophysics Data System (ADS)

Peacock, D. C. P.; Nixon, C. W.; Rotevatn, A.; Sanderson, D. J.; Zuluaga, L. F.

2017-04-01

The way that faults interact with each other controls fault geometries, displacements and strains. Faults rarely occur individually but as sets or networks, with the arrangement of these faults producing a variety of different fault interactions. Fault interactions are characterised in terms of the following: 1) Geometry - the spatial arrangement of the faults. Interacting faults may or may not be geometrically linked (i.e. physically connected), when fault planes share an intersection line. 2) Kinematics - the displacement distributions of the interacting faults and whether the displacement directions are parallel, perpendicular or oblique to the intersection line. Interacting faults may or may not be kinematically linked, where the displacements, stresses and strains of one fault influences those of the other. 3) Displacement and strain in the interaction zone - whether the faults have the same or opposite displacement directions, and if extension or contraction dominates in the acute bisector between the faults. 4) Chronology - the relative ages of the faults. This characterisation scheme is used to suggest a classification for interacting faults. Different types of interaction are illustrated using metre-scale faults from the Mesozoic rocks of Somerset and examples from the literature.

Modeling Aggregation Processes of Lennard-Jones particles Via Stochastic Networks

NASA Astrophysics Data System (ADS)

Forman, Yakir; Cameron, Maria

2017-07-01

We model an isothermal aggregation process of particles/atoms interacting according to the Lennard-Jones pair potential by mapping the energy landscapes of each cluster size N onto stochastic networks, computing transition probabilities from the network for an N-particle cluster to the one for N+1, and connecting these networks into a single joint network. The attachment rate is a control parameter. The resulting network representing the aggregation of up to 14 particles contains 6427 vertices. It is not only time-irreversible but also reducible. To analyze its transient dynamics, we introduce the sequence of the expected initial and pre-attachment distributions and compute them for a wide range of attachment rates and three values of temperature. As a result, we find the configurations most likely to be observed in the process of aggregation for each cluster size. We examine the attachment process and conduct a structural analysis of the sets of local energy minima for every cluster size. We show that both processes taking place in the network, attachment and relaxation, lead to the dominance of icosahedral packing in small (up to 14 atom) clusters.

Uncovering a New Current: The Southwest MAdagascar Coastal Current

NASA Astrophysics Data System (ADS)

Ramanantsoa, Juliano D.; Penven, P.; Krug, M.; Gula, J.; Rouault, M.

2018-02-01

Cruise data sets, satellite remote sensing observations, and model data analyses are combined to highlight the existence of a coastal surface poleward flow in the southwest of Madagascar: the Southwest MAdagascar Coastal Current (SMACC). The SMACC is a relatively shallow (<300 m) and narrow (<100 km wide) warm and salty coastal surface current, which flows along the south western coast of Madagascar toward the south, opposite to the dominant winds. The warm water surface signature of the SMACC extends from 22°S (upstream) to 26.4°S (downstream). The SMACC exhibits a seasonal variability: more intense in summer and reduced in winter. The average volume transport of its core is about 1.3 Sv with a mean summer maximum of 2.1 Sv. It is forced by a strong cyclonic wind stress curl associated with the bending of the trade winds along the southern tip of Madagascar. The SMACC directly influences the coastal upwelling regions south of Madagascar. Its existence is likely to influence local fisheries and larval transport patterns, as well as the connectivity with the Agulhas Current, affecting the returning branch of the global overturning circulation.

The Chajnantor Sub/Millimeter Survey Telescope

NASA Astrophysics Data System (ADS)

Golwala, Sunil

2018-01-01

We are developing the Chajnantor Sub/millimeter Survey Telescope, a project to build a 30-m telescope operating at wavelengths as short as 850 µm with 1 degree field of view for imaging and multi-object spectroscopic surveys. This project will provide massive new data sets for studying star formation at high redshift and in the local universe, feedback mechanisms in galaxy evolution, the structure of galaxy clusters, and the cosmological peculiar velocity field. We will highlight CSST's capabilities for studying galaxy evolution, where it will: trace the evolution of dusty, star-forming galaxies from high redshift to the z ≍ 1-3 epoch when they dominate the cosmic star formation rate; connect this population to the high-redshift rest-frame UV/optical galaxy population; use these dusty galaxies, the most biased overdensities, to guide ultra-deep followup at z > 3.5 and possibly z > 7; measure the brightness of important submm/FIR spectral lines like [CII]; search for molecular and atomic outflows; and do calorimetry of the CGM via the thermal SZ effect. We will describe the expected surveys addressing these science goals, the novel telescope design, and the planned survey instrumentation.

Does personality in small rodents vary depending on population density?

PubMed

Korpela, Katri; Sundell, Janne; Ylönen, Hannu

2011-01-01

Personality means an individual's unique way of behaving and reacting to the environment. It is a stable and heritable trait, which is expressed consistently in different situations. The aim of our study was to develop novel tests to depict the personality structure of the bank vole Myodes glareolus, and to determine if the phase of the population cycle, i.e. population density, affects personality. We focused on some central aspects of bank vole behaviour: mobility, risk taking, exploratory behaviour, dominance, and aggressive behaviour towards pups. These behaviours were chosen because they directly affect bank vole survival or fitness or are classified as important factors of personality in other species. In total, 192 males from different populations went through four behavioural tests, in which 20 variables were measured. The tests were repeated after 3 weeks, which verified that all traits were stable, i.e. repeatable between trials. Three personality compounds emerged, named extroversion, novelty seeking and infanticide. Extroversion included dominance and mobility, while novelty seeking consisted of risk taking and exploration. Infanticide encompassed all indices measuring harmful behaviour towards pups. Mobility and dominance were connected, possibly because both seem to depend on condition. Time spent in captivity increased extroversion, which may be explained by good food, stable conditions and acclimation to strong social cues. Novelty seeking was connected to repeatability which could mean that novelty avoiding individuals adjust their behaviour to match new environments. Population density affected the infanticide trait but not novelty seeking or extroversion.

Specialization and integration of functional thalamocortical connectivity in the human infant.

PubMed

Toulmin, Hilary; Beckmann, Christian F; O'Muircheartaigh, Jonathan; Ball, Gareth; Nongena, Pumza; Makropoulos, Antonios; Ederies, Ashraf; Counsell, Serena J; Kennea, Nigel; Arichi, Tomoki; Tusor, Nora; Rutherford, Mary A; Azzopardi, Denis; Gonzalez-Cinca, Nuria; Hajnal, Joseph V; Edwards, A David

2015-05-19

Connections between the thalamus and cortex develop rapidly before birth, and aberrant cerebral maturation during this period may underlie a number of neurodevelopmental disorders. To define functional thalamocortical connectivity at the normal time of birth, we used functional MRI (fMRI) to measure blood oxygen level-dependent (BOLD) signals in 66 infants, 47 of whom were at high risk of neurocognitive impairment because of birth before 33 wk of gestation and 19 of whom were term infants. We segmented the thalamus based on correlation with functionally defined cortical components using independent component analysis (ICA) and seed-based correlations. After parcellating the cortex using ICA and segmenting the thalamus based on dominant connections with cortical parcellations, we observed a near-facsimile of the adult functional parcellation. Additional analysis revealed that BOLD signal in heteromodal association cortex typically had more widespread and overlapping thalamic representations than primary sensory cortex. Notably, more extreme prematurity was associated with increased functional connectivity between thalamus and lateral primary sensory cortex but reduced connectivity between thalamus and cortex in the prefrontal, insular and anterior cingulate regions. This work suggests that, in early infancy, functional integration through thalamocortical connections depends on significant functional overlap in the topographic organization of the thalamus and that the experience of premature extrauterine life modulates network development, altering the maturation of networks thought to support salience, executive, integrative, and cognitive functions.

Specialization and integration of functional thalamocortical connectivity in the human infant

PubMed Central

Toulmin, Hilary; Beckmann, Christian F.; O'Muircheartaigh, Jonathan; Ball, Gareth; Nongena, Pumza; Makropoulos, Antonios; Ederies, Ashraf; Counsell, Serena J.; Kennea, Nigel; Arichi, Tomoki; Tusor, Nora; Rutherford, Mary A.; Azzopardi, Denis; Gonzalez-Cinca, Nuria; Hajnal, Joseph V.; Edwards, A. David

2015-01-01

Connections between the thalamus and cortex develop rapidly before birth, and aberrant cerebral maturation during this period may underlie a number of neurodevelopmental disorders. To define functional thalamocortical connectivity at the normal time of birth, we used functional MRI (fMRI) to measure blood oxygen level-dependent (BOLD) signals in 66 infants, 47 of whom were at high risk of neurocognitive impairment because of birth before 33 wk of gestation and 19 of whom were term infants. We segmented the thalamus based on correlation with functionally defined cortical components using independent component analysis (ICA) and seed-based correlations. After parcellating the cortex using ICA and segmenting the thalamus based on dominant connections with cortical parcellations, we observed a near-facsimile of the adult functional parcellation. Additional analysis revealed that BOLD signal in heteromodal association cortex typically had more widespread and overlapping thalamic representations than primary sensory cortex. Notably, more extreme prematurity was associated with increased functional connectivity between thalamus and lateral primary sensory cortex but reduced connectivity between thalamus and cortex in the prefrontal, insular and anterior cingulate regions. This work suggests that, in early infancy, functional integration through thalamocortical connections depends on significant functional overlap in the topographic organization of the thalamus and that the experience of premature extrauterine life modulates network development, altering the maturation of networks thought to support salience, executive, integrative, and cognitive functions. PMID:25941391

Cumulative effects of wetland drainage on watershed-scale subsurface hydrologic connectivity

NASA Astrophysics Data System (ADS)

Creed, I. F.; Ameli, A.

2017-12-01

Subsurface hydrologic connectivity influences hydrological, biogeochemical and ecological responses within watersheds. However, information about the location, duration, and frequency of subsurface hydrologic connections within wetlandscapes and between wetlandscapes and streams is often not available. This leads to a lack of understanding of the potential effects of human modifications of the landscape, including wetland degradation and removal, on subsurface hydrologic connectivity and therefore watershed responses. Herein, we develop a computationally efficient, physically-based subsurface hydrologic connectivity model that explicitly characterizes the effects of wetland degradation and removal on the distribution, length, and timing of subsurface hydrologic connectivity within a wetland-dominated watershed in the Prairie Pothole Region of North America. We run the model using a time series of wetland inventories that reflect incremental wetland loss from 1962, to 1993, and to 2009. We also consider a potential future wetland loss scenario based on removal of all wetlands outside of the protected areas of the watershed. Our findings suggest that wetland degradation and removal over this period increased the average length, transit time, and frequency of subsurface hydrologic connections to the regional surface waters, resulting in decreased baseflow in the major river network. This study provides important insights that can be used by wetland managers and policy makers to support watershed-scale wetland protection and restoration plans to improve water resource management.

A Theoretical Synthesis of Knowledge Sharing and Educational Leadership for Sustaining Learning Communities

ERIC Educational Resources Information Center

Rungrojngarmcharoen, Kanog on

2013-01-01

Knowledge is one of the crucial and dominant economic resources in order to obtain sustainable advantages in any community. The world is now shifting faster thanks to the advanced development of digital connectivity and increasing access to knowledge. Leaders of a community, society, or country must contemplate what factors concerned in the…

Density matrix solutions for the susceptibilities of a three-level system with arbitrary relaxation rates and field strengths

NASA Technical Reports Server (NTRS)

Ryan, J. C.; Lawandy, N. M.

1986-01-01

The susceptibilities for a three-level system with arbitrary pump and signal field strengths are derived for arbitrary longitudinal and transverse relaxation rates. The results are of interest in connection with the calculation of the Raman gain in systems where resonance enhancement plays a dominant role.

The Prisoner's Dilemma and Economics 101: Do Active Learning Exercises Correlate with Student Performance?

ERIC Educational Resources Information Center

Byun, Chong Hyun Christie

2014-01-01

The importance of active learning in the classroom has been well established in the field of Economic education. This paper examines the connection between active learning and performance outcomes in an Economics 101 course. Students participated in single play simultaneous move game with a clear dominant strategy, modeled after the Prisoner's…

Assimilation in the Puerto Rican Communities of the U.S.: A New Focus

ERIC Educational Resources Information Center

Rodriguez, Clara

The experiences of Puerto Rican migrants in New York City and elsewhere are unique when compared to those of other minority groups. The Puerto Ricans, in general, are disinclined to assimilate into the dominant American culture, and this phenomenon is closely connected to Puerto Rico's political and economic relationship to the United States.…

Ecosystem services and preventive medicine a natural connection

Treesearch

Viniece L. Jennings; Claire K. Larson; Lincoln R. Larson

2016-01-01

Modern public health challenges require inter- disciplinary solutions that integrate knowl- edge of  human behavior and its complex relationship with the physical environment. Historically, this discourse was dominated by studies  of hazards and other negative health consequences associated with human–environment interactions.  However, growing evidence1 suggests that...

Role of xyloglucan in cotton (Gossypium hirsutum L.) fiber elongation of the short fiber mutant Ligon-lintless-2 (Li2)

USDA-ARS?s Scientific Manuscript database

Xyloglucan is a matrix polysaccharide found in the cell walls of all land plants. In growing cells, xyloglucan is thought to connect cellulose microfibrils and regulate their separation during wall extension. Ligon lintless-2 (Li2), a monogenic dominant cotton fiber mutation, that causes extreme red...

Why sustain oak forests?

Treesearch

David Wm. Smith

2006-01-01

A brief overview and some personal thoughts are offered that deal with the implications of our social and political systems on the long-term sustainability of our forest resources. The connection of the most recent climatic events, in a geologic-time context, to the development of present day oak dominated forests of the Eastern United States is discussed. The impacts...

Osteogenesis Imperfecta

PubMed Central

Sam, Justin Easow; Dharmalingam, Mala

2017-01-01

Osteogenesis imperfecta is a common heritable connective tissue disorder. Nearly ninety percent are due to Type I collagen mutations. Type I-IV are autosomal dominant, and Type VI–XIII are autosomal recessive. They are Graded 1-5 based on severity. Genomic testing is done by collagen analysis from fibroblasts. The mainstay of treatment is bisphosphonate therapy. The prognosis is variable. PMID:29285457

20 CFR 202.9 - Controlled company or person not principally engaged in service or operation in connection with...

Code of Federal Regulations, 2010 CFR

2010-04-01

... which is principally engaged in some other business, the Board will require the submission of information pertaining to the history and all operations of such company or person with a view to determining... was established; (2) The functional dominance or subservience of its business which constitutes a...

Language Development among Immigrant Students from the Perspectives of Two Different Assimilated Instructors

ERIC Educational Resources Information Center

Porras, Dehlly; Matthews, Robert

2009-01-01

The authors present two experiences of assimilation, "melting-pot" and "salad-bowl" processes, their connections to the WASP framework of skin color, language, and religion, and their influences in the classroom. They focus on how fluency in the English language is the dominant assimilation factor for immigrant students and share their experiences…

Scaramouche Goes to Preschool: The Complex Matrix of Young Children's Everyday Music

ERIC Educational Resources Information Center

Ilari, Beatriz

2018-01-01

This article examines everyday musical practices and their connections to young children's learning and development, in and through music. It begins with a discussion of music learning in early childhood as a form of participation and levels of intention in learning. Next, conceptions of child that have dominated early childhood music education…

STEM Learning Research through a Funds of Knowledge Lens

ERIC Educational Resources Information Center

Civil, Marta

2016-01-01

This article examines STEM learning as a cultural process with a focus on non-dominant communities. Building on my work in funds of knowledge and mathematics education, I present three vignettes to raise some questions around connections between in-school and out-of-school mathematics. How do we define competence? How do task and environment…

Perceptions about the Dominance of English as a Global Language: Impact on Foreign-Language Teachers' Professional Identity

ERIC Educational Resources Information Center

Gayton, Angela Mary

2016-01-01

Using a novel theoretical framework that incorporates teacher identity, a school as community of practice, and English as a global language from a linguistic-imperialism perspective, this qualitative interview study with foreign-language teachers in Scotland, France, and Germany (N = 13) explores connections between foreign-language-learning…

On the Relationship between EFL Teachers' Classroom Management Approaches and the Dominant Teaching Style: A Mixed Method Study

ERIC Educational Resources Information Center

Kazemi, Ali; Soleimani, Neda

2016-01-01

As a factor contributing to a successful teaching career, classroom management can be affected by many latent and explicit variables. In this mixed method study, the researchers sought to scrutinize the possible connections among EFL teachers' classroom management approaches at two dimensions of behavior management and instructional management and…

Connecting to Your Community through Birds and Citizen Science

ERIC Educational Resources Information Center

Fee, Jennifer; Trautmann, Nancy

2012-01-01

Birds are among the most fascinating creatures on Earth, found on every continent and prevalent even in human-dominated landscapes. Some are beautiful, others are accomplished singers, and all play important roles in the ecosystems in which they live. Even amateur birders have made important discoveries about birds, and there is still a lot to…

Education and Violation: Conceptualizing Power, Domination, and Agency in the Hidden Curriculum

ERIC Educational Resources Information Center

De Lissovoy, Noah

2012-01-01

This article offers a theory of a process of "violation" that connects macropolitical effects to the intimate terrain of subject production. I describe power, as violation, in terms of a simultaneous process of construction and destruction, which seeks its satisfaction in an injury to the very identities it is complicit in producing. Starting from…

Fine-Grained Parcellation of Brain Connectivity Improves Differentiation of States of Consciousness During Graded Propofol Sedation.

PubMed

Liu, Xiaolin; Lauer, Kathryn K; Ward, B Douglas; Roberts, Christopher J; Liu, Suyan; Gollapudy, Suneeta; Rohloff, Robert; Gross, William; Xu, Zhan; Chen, Guangyu; Binder, Jeffrey R; Li, Shi-Jiang; Hudetz, Anthony G

2017-08-01

Conscious perception relies on interactions between spatially and functionally distinct modules of the brain at various spatiotemporal scales. These interactions are altered by anesthesia, an intervention that leads to fading consciousness. Relatively little is known about brain functional connectivity and its anesthetic modulation at a fine spatial scale. Here, we used functional imaging to examine propofol-induced changes in functional connectivity in brain networks defined at a fine-grained parcellation based on a combination of anatomical and functional features. Fifteen healthy volunteers underwent resting-state functional imaging in wakeful baseline, mild sedation, deep sedation, and recovery of consciousness. Compared with wakeful baseline, propofol produced widespread, dose-dependent functional connectivity changes that scaled with the extent to which consciousness was altered. The dominant changes in connectivity were associated with the frontal lobes. By examining node pairs that demonstrated a trend of functional connectivity change between wakefulness and deep sedation, quadratic discriminant analysis differentiated the states of consciousness in individual participants more accurately at a fine-grained parcellation (e.g., 2000 nodes) than at a coarse-grained parcellation (e.g., 116 anatomical nodes). Our study suggests that defining brain networks at a high granularity may provide a superior imaging-based distinction of the graded effect of anesthesia on consciousness.

Spontaneous eyelid closures link vigilance fluctuation with fMRI dynamic connectivity states

PubMed Central

Wang, Chenhao; Ong, Ju Lynn; Patanaik, Amiya; Chee, Michael W. L.

2016-01-01

Fluctuations in resting-state functional connectivity occur but their behavioral significance remains unclear, largely because correlating behavioral state with dynamic functional connectivity states (DCS) engages probes that disrupt the very behavioral state we seek to observe. Observing spontaneous eyelid closures following sleep deprivation permits nonintrusive arousal monitoring. During periods of low arousal dominated by eyelid closures, sliding-window correlation analysis uncovered a DCS associated with reduced within-network functional connectivity of default mode and dorsal/ventral attention networks, as well as reduced anticorrelation between these networks. Conversely, during periods when participants’ eyelids were wide open, a second DCS was associated with less decoupling between the visual network and higher-order cognitive networks that included dorsal/ventral attention and default mode networks. In subcortical structures, eyelid closures were associated with increased connectivity between the striatum and thalamus with the ventral attention network, and greater anticorrelation with the dorsal attention network. When applied to task-based fMRI data, these two DCS predicted interindividual differences in frequency of behavioral lapsing and intraindividual temporal fluctuations in response speed. These findings with participants who underwent a night of total sleep deprivation were replicated in an independent dataset involving partially sleep-deprived participants. Fluctuations in functional connectivity thus appear to be clearly associated with changes in arousal. PMID:27512040

Intermediate disturbance in experimental landscapes improves persistence of beetle metapopulations.

PubMed

Govindan, Byju N; Feng, Zhilan; DeWoody, Yssa D; Swihart, Robert K

2015-03-01

Human-dominated landscapes often feature patches that fluctuate in suitability through space and time, but there is little experimental evidence relating the consequences of dynamic patches for species persistence. We used a spatially and temporally dynamic metapopulation model to assess and compare metapopulation capacity and persistence for red flour beetles (Tribolium castaneum) in experimental landscapes differentiated by resource structure, patch dynamics (destruction and restoration), and connectivity. High connectivity increased the colonization rate of beetles, but this effect was less pronounced in heterogeneous relative to homogeneous landscapes. Higher connectivity and faster patch dynamics increased extinction rates in landscapes. Lower connectivity promoted density-dependent emigration. Heterogeneous landscapes containing patches of different carrying capacity enhanced landscape-level occupancy probability. The highest metapopulation capacity and persistence was observed in landscapes with heterogeneous patches, low connectivity, and slow patch dynamics. Control landscapes with no patch dynamics exhibited rapid declines in abundance and approached extinction due to increased adult mortality in the matrix, higher pupal cannibalism by adults, and extremely low rates of exchange between remaining habitable patches. Our results highlight the role of intermediate patch dynamics, intermediate connectivity, and the nature of density dependence of emigration for persistence of species in heterogeneous landscapes. Our results also demonstrate the importance of incorporating local dynamics into the estimation of metapopulation capacity for conservation planning.

The brain network reflecting bodily self-consciousness: a functional connectivity study

PubMed Central

Ionta, Silvio; Martuzzi, Roberto; Salomon, Roy

2014-01-01

Several brain regions are important for processing self-location and first-person perspective, two important aspects of bodily self-consciousness. However, the interplay between these regions has not been clarified. In addition, while self-location and first-person perspective in healthy subjects are associated with bilateral activity in temporoparietal junction (TPJ), disturbed self-location and first-person perspective result from damage of only the right TPJ. Identifying the involved brain network and understanding the role of hemispheric specializations in encoding self-location and first-person perspective, will provide important information on system-level interactions neurally mediating bodily self-consciousness. Here, we used functional connectivity and showed that right and left TPJ are bilaterally connected to supplementary motor area, ventral premotor cortex, insula, intraparietal sulcus and occipitotemporal cortex. Furthermore, the functional connectivity between right TPJ and right insula had the highest selectivity for changes in self-location and first-person perspective. Finally, functional connectivity revealed hemispheric differences showing that self-location and first-person perspective modulated the connectivity between right TPJ, right posterior insula, and right supplementary motor area, and between left TPJ and right anterior insula. The present data extend previous evidence on healthy populations and clinical observations in neurological deficits, supporting a bilateral, but right-hemispheric dominant, network for bodily self-consciousness. PMID:24396007

Optimal design of dampers within seismic structures

NASA Astrophysics Data System (ADS)

Ren, Wenjie; Qian, Hui; Song, Wali; Wang, Liqiang

2009-07-01

An improved multi-objective genetic algorithm for structural passive control system optimization is proposed. Based on the two-branch tournament genetic algorithm, the selection operator is constructed by evaluating individuals according to their dominance in one run. For a constrained problem, the dominance-based penalty function method is advanced, containing information on an individual's status (feasible or infeasible), position in a search space, and distance from a Pareto optimal set. The proposed approach is used for the optimal designs of a six-storey building with shape memory alloy dampers subjected to earthquake. The number and position of dampers are chosen as the design variables. The number of dampers and peak relative inter-storey drift are considered as the objective functions. Numerical results generate a set of non-dominated solutions.

Downstream cumulative effects of land use on freshwater communities

NASA Astrophysics Data System (ADS)

Kuglerová, L.; Kielstra, B. W.; Moore, D.; Richardson, J. S.

2015-12-01

Many streams and rivers are subject to disturbance from intense land use such as urbanization and agriculture, and this is especially obvious for small headwaters. Streams are spatially organized into networks where headwaters represent the tributaries and provide water, nutrients, and organic material to the main stems. Therefore perturbations within the headwaters might be cumulatively carried on downstream. Although we know that the disturbance of headwaters in urban and agricultural landscapes poses threats to downstream river reaches, the magnitude and severity of these changes for ecological communities is less known. We studied stream networks along a gradient of disturbance connected to land use intensity, from urbanized watersheds to watersheds placed in agricultural settings in the Greater Toronto Area. Further, we compared the patterns and processes found in the modified watershed to a control watershed, situated in a forested, less impacted landscape. Preliminary results suggest that hydrological modifications (flash floods), habitat loss (drainage and sewer systems), and water quality issues of small streams in urbanized and agricultural watersheds represent major disturbances and threats for aquatic and riparian biota on local as well as larger spatial scales. For example, communities of riparian plants are dominated by species typical of the land use on adjacent uplands as well as the dominant land use on the upstream contributing area, instead of riparian obligates commonly found in forested watersheds. Further, riparian communities in disturbed environments are dominated by invasive species. The changes in riparian communities are vital for various functions of riparian vegetation. Bank erosion control is suppressed, leading to severe channel transformations and sediment loadings in urbanized watersheds. Food sources for instream biota and thermal regimes are also changed, which further triggers alterations of in-stream biological communities. These findings clearly demonstrate that in watersheds which are disturbed by intensive land use, the eco-hydrological linkages between biota and fluvial processes significantly differ from those in more natural and forested landscapes.

Spectroscopic and computational studies of matrix-isolated iso-CHBr{sub 3}: Structure, properties, and photochemistry of iso-bromoform

DOE Office of Scientific and Technical Information (OSTI.GOV)

George, Lisa; Kalume, Aimable; Wagner, James

Iso-polyhalomethanes are known reactive intermediates that play a pivotal role in the photochemistry of halomethanes in condensed phases. In this work, iso-bromoform (iso-CHBr{sub 3}) and its deuterated isotopomer were characterized by matrix isolation infrared and UV/visible spectroscopy, supported by ab initio and density functional theory calculations, to further probe the structure, spectroscopy, and photochemistry of this important intermediate. Selected wavelength laser irradiation of CHBr{sub 3} isolated in Ar or Ne matrices at {approx}5 K yielded iso-CHBr{sub 3}; the observed infrared and UV/visible absorptions are in excellent agreement with computational predictions, and the energies of various stationary points on the CHBr{submore » 3} potential energy surface were characterized computationally using high-level methods in combination with correlation consistent basis sets. These calculations show that, while the corresponding minima lie {approx}200 kJ/mol above the global CHBr{sub 3} minimum, the isomer is bound by some 60 kJ/mol in the gas phase with respect to the CHBr{sub 2}+ Br asymptote. The photochemistry of iso-CHBr{sub 3} was investigated by selected wavelength laser irradiation into the intense S{sub 0}{yields} S{sub 3} transition, which resulted in back photoisomerization to CHBr{sub 3}. Intrinsic reaction coordinate calculations confirmed the existence of a first-order saddle point connecting the two isomers, which lies energetically below the threshold of the radical channel. Subsequently, natural bond orbital analysis and natural resonance theory were used to characterize the important resonance structures of the isomer and related stationary points, which demonstrate that the isomerization transition state represents a crossover from dominantly covalent to dominantly ionic bonding. In condensed phases, the ion-pair dominated isomerization transition state structure is preferentially stabilized, so that the barrier to isomerization is lowered.« less

Functional Connectivity of Precipitation Networks in the Brazilian Rainforest-Savanna Transition Zone

NASA Astrophysics Data System (ADS)

Adera, S.; Larsen, L.; Levy, M. C.; Thompson, S. E.

2016-12-01

In the Brazilian rainforest-savanna transition zone, vegetation change has the potential to significantly affect precipitation patterns. Deforestation, in particular, can affect precipitation patterns by increasing land surface albedo, increasing aerosol loading to the atmosphere, changing land surface roughness, and reducing transpiration. Understanding land surface-precipitation couplings in this region is important not only for sustaining Amazon and Cerrado ecosystems, but also for cattle ranching and agriculture, hydropower generation, and drinking water management. Simulations suggest complex, scale-dependent interactions between precipitation and land cover. For example, the size and distribution of deforested patches has been found to affect precipitation patterns. We take an empirical approach to ask: (1) what are the dominant spatial and temporal length scales of precipitation coupling in the Brazilian rainforest-savanna transition zone? (2) How do these length scales change over time? (3) How does the connectivity of precipitation change over time? The answers to these questions will help address fundamental questions about the impacts of deforestation on precipitation. We use rain gauge data from 1100 rain gauges intermittently covering the period 1980 - 2013, a period of intensive land cover change in the region. The dominant spatial and temporal length scales of precipitation coupling are resolved using transfer entropy, a metric from information theory. Connectivity of the emergent network of couplings is quantified using network statistics. Analyses using transfer entropy and network statistics reveal the spatial and temporal interdependencies of rainfall events occurring in different parts of the study domain.

Estimating wetland connectivity to streams in the Prairie Pothole Region: An isotopic and remote sensing approach

USGS Publications Warehouse

Brooks, J. R.; Mushet, David M.; Vanderhoof, Melanie; Leibowitz, Scott G.; Neff, Brian; Christensen, J. R.; Rosenberry, Donald O.; Rugh, W. D.; Alexander, L.C.

2018-01-01

Understanding hydrologic connectivity between wetlands and perennial streams is critical to understanding the reliance of stream flow on inputs from wetlands. We used the isotopic evaporation signal in water and remote sensing to examine wetland‐stream hydrologic connectivity within the Pipestem Creek watershed, North Dakota, a watershed dominated by prairie‐pothole wetlands. Pipestem Creek exhibited an evaporated‐water signal that had approximately half the isotopic‐enrichment signal found in most evaporatively enriched prairie‐pothole wetlands. Groundwater adjacent to Pipestem Creek had isotopic values that indicated recharge from winter precipitation and had no significant evaporative enrichment, indicating that enriched surface water did not contribute significantly to groundwater discharging into Pipestem Creek. The estimated surface water area necessary to generate the evaporation signal within Pipestem Creek was highly dynamic, varied primarily with the amount of discharge, and was typically greater than the immediate Pipestem Creek surface water area, indicating that surficial flow from wetlands contributed to stream flow throughout the summer. We propose a dynamic range of spilling thresholds for prairie‐pothole wetlands across the watershed allowing for wetland inputs even during low‐flow periods. Combining Landsat estimates with the isotopic approach allowed determination of potential (Landsat) and actual (isotope) contributing areas in wetland‐dominated systems. This combined approach can give insights into the changes in location and magnitude of surface water and groundwater pathways over time. This approach can be used in other areas where evaporation from wetlands results in a sufficient evaporative isotopic signal.

A method for functional network connectivity among spatially independent resting-state components in schizophrenia.

PubMed

Jafri, Madiha J; Pearlson, Godfrey D; Stevens, Michael; Calhoun, Vince D

2008-02-15

Functional connectivity of the brain has been studied by analyzing correlation differences in time courses among seed voxels or regions with other voxels of the brain in healthy individuals as well as in patients with brain disorders. The spatial extent of strongly temporally coherent brain regions co-activated during rest has also been examined using independent component analysis (ICA). However, the weaker temporal relationships among ICA component time courses, which we operationally define as a measure of functional network connectivity (FNC), have not yet been studied. In this study, we propose an approach for evaluating FNC and apply it to functional magnetic resonance imaging (fMRI) data collected from persons with schizophrenia and healthy controls. We examined the connectivity and latency among ICA component time courses to test the hypothesis that patients with schizophrenia would show increased functional connectivity and increased lag among resting state networks compared to controls. Resting state fMRI data were collected and the inter-relationships among seven selected resting state networks (identified using group ICA) were evaluated by correlating each subject's ICA time courses with one another. Patients showed higher correlation than controls among most of the dominant resting state networks. Patients also had slightly more variability in functional connectivity than controls. We present a novel approach for quantifying functional connectivity among brain networks identified with spatial ICA. Significant differences between patient and control connectivity in different networks were revealed possibly reflecting deficiencies in cortical processing in patients.

A Method for Functional Network Connectivity Among Spatially Independent Resting-State Components in Schizophrenia

PubMed Central

Jafri, Madiha J; Pearlson, Godfrey D; Stevens, Michael; Calhoun, Vince D

2011-01-01

Functional connectivity of the brain has been studied by analyzing correlation differences in time courses among seed voxels or regions with other voxels of the brain in patients versus controls. The spatial extent of strongly temporally coherent brain regions co-activated during rest has also been examined using independent component analysis (ICA). However, the weaker temporal relationships among ICA component time courses, which we operationally define as a measure of functional network connectivity (FNC), have not yet been studied. In this study, we propose an approach for evaluating FNC and apply it to functional magnetic resonance imaging (fMRI) data collected from persons with schizophrenia and healthy controls. We examined the connectivity and latency among ICA component time courses to test the hypothesis that patients with schizophrenia would show increased functional connectivity and increased lag among resting state networks compared to controls. Resting state fMRI data were collected and the inter-relationships among seven selected resting state networks (identified using group ICA) were evaluated by correlating each subject’s ICA time courses with one another. Patients showed higher correlation than controls among most of the dominant resting state networks. Patients also had slightly more variability in functional connectivity than controls. We present a novel approach for quantifying functional connectivity among brain networks identified with spatial ICA. Significant differences between patient and control connectivity in different networks were revealed possibly reflecting deficiencies in cortical processing in patients. PMID:18082428

Representation and display of vector field topology in fluid flow data sets

NASA Technical Reports Server (NTRS)

Helman, James; Hesselink, Lambertus

1989-01-01

The visualization of physical processes in general and of vector fields in particular is discussed. An approach to visualizing flow topology that is based on the physics and mathematics underlying the physical phenomenon is presented. It involves determining critical points in the flow where the velocity vector vanishes. The critical points, connected by principal lines or planes, determine the topology of the flow. The complexity of the data is reduced without sacrificing the quantitative nature of the data set. By reducing the original vector field to a set of critical points and their connections, a representation of the topology of a two-dimensional vector field that is much smaller than the original data set but retains with full precision the information pertinent to the flow topology is obtained. This representation can be displayed as a set of points and tangent curves or as a graph. Analysis (including algorithms), display, interaction, and implementation aspects are discussed.

Integration of Network Topological and Connectivity Properties for Neuroimaging Classification

PubMed Central

Jie, Biao; Gao, Wei; Wang, Qian; Wee, Chong-Yaw

2014-01-01

Rapid advances in neuroimaging techniques have provided an efficient and noninvasive way for exploring the structural and functional connectivity of the human brain. Quantitative measurement of abnormality of brain connectivity in patients with neurodegenerative diseases, such as mild cognitive impairment (MCI) and Alzheimer’s disease (AD), have also been widely reported, especially at a group level. Recently, machine learning techniques have been applied to the study of AD and MCI, i.e., to identify the individuals with AD/MCI from the healthy controls (HCs). However, most existing methods focus on using only a single property of a connectivity network, although multiple network properties, such as local connectivity and global topological properties, can potentially be used. In this paper, by employing multikernel based approach, we propose a novel connectivity based framework to integrate multiple properties of connectivity network for improving the classification performance. Specifically, two different types of kernels (i.e., vector-based kernel and graph kernel) are used to quantify two different yet complementary properties of the network, i.e., local connectivity and global topological properties. Then, multikernel learning (MKL) technique is adopted to fuse these heterogeneous kernels for neuroimaging classification. We test the performance of our proposed method on two different data sets. First, we test it on the functional connectivity networks of 12 MCI and 25 HC subjects. The results show that our method achieves significant performance improvement over those using only one type of network property. Specifically, our method achieves a classification accuracy of 91.9%, which is 10.8% better than those by single network-property-based methods. Then, we test our method for gender classification on a large set of functional connectivity networks with 133 infants scanned at birth, 1 year, and 2 years, also demonstrating very promising results. PMID:24108708

Coupled Harmonic Bases for Longitudinal Characterization of Brain Networks

PubMed Central

Hwang, Seong Jae; Adluru, Nagesh; Collins, Maxwell D.; Ravi, Sathya N.; Bendlin, Barbara B.; Johnson, Sterling C.; Singh, Vikas

2016-01-01

There is a great deal of interest in using large scale brain imaging studies to understand how brain connectivity evolves over time for an individual and how it varies over different levels/quantiles of cognitive function. To do so, one typically performs so-called tractography procedures on diffusion MR brain images and derives measures of brain connectivity expressed as graphs. The nodes correspond to distinct brain regions and the edges encode the strength of the connection. The scientific interest is in characterizing the evolution of these graphs over time or from healthy individuals to diseased. We pose this important question in terms of the Laplacian of the connectivity graphs derived from various longitudinal or disease time points — quantifying its progression is then expressed in terms of coupling the harmonic bases of a full set of Laplacians. We derive a coupled system of generalized eigenvalue problems (and corresponding numerical optimization schemes) whose solution helps characterize the full life cycle of brain connectivity evolution in a given dataset. Finally, we show a set of results on a diffusion MR imaging dataset of middle aged people at risk for Alzheimer’s disease (AD), who are cognitively healthy. In such asymptomatic adults, we find that a framework for characterizing brain connectivity evolution provides the ability to predict cognitive scores for individual subjects, and for estimating the progression of participant’s brain connectivity into the future. PMID:27812274

DOE Office of Scientific and Technical Information (OSTI.GOV)

T. H. Brikowski; D. L. Norton; D. D. Blackwell

Final project report of natural state modeling effort for The Geysers geothermal field, California. Initial models examined the liquid-dominated state of the system, based on geologic constraints and calibrated to match observed whole rock delta-O18 isotope alteration. These models demonstrated that the early system was of generally low permeability (around 10{sup -12} m{sup 2}), with good hydraulic connectivity at depth (along the intrusive contact) and an intact caprock. Later effort in the project was directed at development of a two-phase, supercritical flow simulation package (EOS1sc) to accompany the Tough2 flow simulator. Geysers models made using this package show that ''simmering'',more » or the transient migration of vapor bubbles through the hydrothermal system, is the dominant transition state as the system progresses to vapor-dominated. Such a system is highly variable in space and time, making the rock record more difficult to interpret, since pressure-temperature indicators likely reflect only local, short duration conditions.« less

Hydrate-Bearing Clayey Sediments: Morphology, Physical Properties, Production and Engineering/Geological Implications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dai, Sheng; Santamarina, J. Carlos

Fine-grained sediments host more than 90 percent of global gas hydrate accumulation. However, hydrate formation in clay-dominated sediments is less understood and characterized than other types of hydrate occurrence. There is an inadequate understanding of hydrate formation mechanisms, segregation structures, hydrate lens topology, system connectivity, and physical macro-scale properties of clay-dominated hydrate-bearing sediments. This situation hinders further analyses of the global carbon budget as well as engineering challenges/solutions related to hydrate instability and production. This project studies hydrate-bearing clay-dominated sediments with emphasis on the enhanced fundamental understanding of hydrate formation and resulting morphology, the development laboratory techniques to emulate naturalmore » hydrate formations, the assessment of analytical tools to predict physical properties, the evaluation of engineering and geological implications, and the advanced understanding of gas production potential from finegrained sediments.« less

Youth–adult partnership: exploring contributions to empowerment, agency and community connections in Malaysian youth programs.

PubMed

Krauss, Steven Eric; Collura, Jessica; Zeldin, Shepherd; Ortega, Adriana; Abdullah, Haslinda; Sulaiman, Abdul Hadi

2014-09-01

Youth–adult partnership (Y–AP) has emerged as a key practice for enacting two features of effective developmental settings: supportive adult relationships and support for efficacy and mattering. Previous studies have shown that when youth, supported by adults, actively participate in organizational and community decision making they are likely to show greater confidence and agency, empowerment and critical consciousness, and community connections. Most of the extant research on Y–AP is limited to qualitative studies and the identification of organizational best practices. Almost all research focuses on Western sociocultural settings. To address these gaps, 299 youth, age 15 to 24, were sampled from established afterschool and community programs in Malaysia to explore the contribution of Y–AP (operationalized as having two components: youth voice in decision-making and supportive adult relationships) to empowerment, agency and community connections. As hypothesized, hierarchical regressions indicated that program quality (Y–AP, safe environment and program engagement) contributed to agency, empowerment and community connections beyond the contribution of family, school and religion. Additionally, the Y–AP measures contributed substantially more variance than the other measures of program quality on each outcome. Interaction effects indicated differences by age for empowerment and agency but not for community connections. The primary findings in this inquiry replicate those found in previous interview and observational-oriented studies. The data suggests fertile ground for future research while demonstrating that Y–AP may be an effective practice for positive youth development outside of Western settings.

Using the International Directory Network and connected information systems for research in the Earth and space sciences

NASA Technical Reports Server (NTRS)

Thieman, J. R.

1994-01-01

Many researchers are becoming aware of the International Directory Network (IDN), an interconnected federation of international directories to Earth and space science data. Are you aware, however, of the many Earth-science-relevant information systems which can be accessed automatically from the directories? After determining potentially useful data sets in various disciplines through directories such as the Global Change Master Directory, it is becoming increasingly possible to get detailed information about the correlative possibilities of these data sets through the connected guide/catalog and inventory systems. Such capabilities as data set browse, subsetting, analysis, etc. are available now and will be improving in the future.

Estimation of Dynamic Sparse Connectivity Patterns From Resting State fMRI.

PubMed

Cai, Biao; Zille, Pascal; Stephen, Julia M; Wilson, Tony W; Calhoun, Vince D; Wang, Yu Ping

2018-05-01

Functional connectivity (FC) estimated from functional magnetic resonance imaging (fMRI) time series, especially during resting state periods, provides a powerful tool to assess human brain functional architecture in health, disease, and developmental states. Recently, the focus of connectivity analysis has shifted toward the subnetworks of the brain, which reveals co-activating patterns over time. Most prior works produced a dense set of high-dimensional vectors, which are hard to interpret. In addition, their estimations to a large extent were based on an implicit assumption of spatial and temporal stationarity throughout the fMRI scanning session. In this paper, we propose an approach called dynamic sparse connectivity patterns (dSCPs), which takes advantage of both matrix factorization and time-varying fMRI time series to improve the estimation power of FC. The feasibility of analyzing dynamic FC with our model is first validated through simulated experiments. Then, we use our framework to measure the difference between young adults and children with real fMRI data set from the Philadelphia Neurodevelopmental Cohort (PNC). The results from the PNC data set showed significant FC differences between young adults and children in four different states. For instance, young adults had reduced connectivity between the default mode network and other subnetworks, as well as hyperconnectivity within the visual system in states 1 and 3, and hypoconnectivity in state 2. Meanwhile, they exhibited temporal correlation patterns that changed over time within functional subnetworks. In addition, the dSCPs model indicated that older people tend to spend more time within a relatively connected FC pattern. Overall, the proposed method provides a valid means to assess dynamic FC, which could facilitate the study of brain networks.

Greenland Subglacial Drainage Evolution Regulated by Weakly Connected Regions of the Bed

NASA Technical Reports Server (NTRS)

Hoffman, Matthew J.; Andrews, Lauren C.; Price, Stephen F.; Catania, Ginny A.; Neumann, Thomas A.; Luthi, Martin P.; Gulley, Jason; Ryser, Claudia; Hawley, Robert L.; Morriss, Blaine

2016-01-01

Penetration of surface meltwater to the bed of the Greenland Ice Sheet each summer causes an initial increase in ice speed due to elevated basal water pressure, followed by slowdown in late summer that continues into fall and winter. While this seasonal pattern is commonly explained by an evolution of the subglacial drainage system from an inefficient distributed to efficient channelized configuration, mounting evidence indicates that subglacial channels are unable to explain important aspects of hydrodynamic coupling in late summer and fall. Here we use numerical models of subglacial drainage and ice flow to show that limited, gradual leakage of water and lowering of water pressure in weakly connected regions of the bed can explain the dominant features in late and post melt season ice dynamics. These results suggest that a third weakly connected drainage component should be included in the conceptual model of subglacial hydrology.

Greenland subglacial drainage evolution regulated by weakly connected regions of the bed

PubMed Central

Hoffman, Matthew J.; Andrews, Lauren C.; Price, Stephen A.; Catania, Ginny A.; Neumann, Thomas A.; Lüthi, Martin P.; Gulley, Jason; Ryser, Claudia; Hawley, Robert L.; Morriss, Blaine

2016-01-01

Penetration of surface meltwater to the bed of the Greenland Ice Sheet each summer causes an initial increase in ice speed due to elevated basal water pressure, followed by slowdown in late summer that continues into fall and winter. While this seasonal pattern is commonly explained by an evolution of the subglacial drainage system from an inefficient distributed to efficient channelized configuration, mounting evidence indicates that subglacial channels are unable to explain important aspects of hydrodynamic coupling in late summer and fall. Here we use numerical models of subglacial drainage and ice flow to show that limited, gradual leakage of water and lowering of water pressure in weakly connected regions of the bed can explain the dominant features in late and post melt season ice dynamics. These results suggest that a third weakly connected drainage component should be included in the conceptual model of subglacial hydrology. PMID:27991518

Greenland subglacial drainage evolution regulated by weakly connected regions of the bed

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hoffman, Matthew J.; Andrews, Lauren C.; Price, Stephen A.

Penetration of surface meltwater to the bed of the Greenland Ice Sheet each summer causes an initial increase in ice speed due to elevated basal water pressure, followed by slowdown in late summer that continues into fall and winter. While this seasonal pattern is commonly explained by an evolution of the subglacial drainage system from an inefficient distributed to efficient channelized configuration, mounting evidence indicates that subglacial channels are unable to explain important aspects of hydrodynamic coupling in late summer and fall. Here we use numerical models of subglacial drainage and ice flow to show that limited, gradual leakage ofmore » water and lowering of water pressure in weakly connected regions of the bed can explain the dominant features in late and post melt season ice dynamics. Finally, these results suggest that a third weakly connected drainage component should be included in the conceptual model of subglacial hydrology.« less

Greenland subglacial drainage evolution regulated by weakly connected regions of the bed.

PubMed

Hoffman, Matthew J; Andrews, Lauren C; Price, Stephen A; Catania, Ginny A; Neumann, Thomas A; Lüthi, Martin P; Gulley, Jason; Ryser, Claudia; Hawley, Robert L; Morriss, Blaine

2016-12-19

Penetration of surface meltwater to the bed of the Greenland Ice Sheet each summer causes an initial increase in ice speed due to elevated basal water pressure, followed by slowdown in late summer that continues into fall and winter. While this seasonal pattern is commonly explained by an evolution of the subglacial drainage system from an inefficient distributed to efficient channelized configuration, mounting evidence indicates that subglacial channels are unable to explain important aspects of hydrodynamic coupling in late summer and fall. Here we use numerical models of subglacial drainage and ice flow to show that limited, gradual leakage of water and lowering of water pressure in weakly connected regions of the bed can explain the dominant features in late and post melt season ice dynamics. These results suggest that a third weakly connected drainage component should be included in the conceptual model of subglacial hydrology.

Competition among networks highlights the power of the weak

PubMed Central

Iranzo, Jaime; Buldú, Javier M.; Aguirre, Jacobo

2016-01-01

The unpreventable connections between real networked systems have recently called for an examination of percolation, diffusion or synchronization phenomena in multilayer networks. Here we use network science and game theory to explore interactions in networks-of-networks and model these as a game for gaining importance. We propose a viewpoint where networks choose the connection strategies, in contrast with classical approaches where nodes are the active players. Specifically, we investigate how creating paths between networks leads to different Nash equilibria that determine their structural and dynamical properties. In a wide variety of cases, selecting adequate connections leads to a cooperative solution that allows weak networks to overcome the strongest opponent. Counterintuitively, each weak network can induce a global transition to such cooperative configuration regardless of the actions of the strongest network. This power of the weak reveals a critical dominance of the underdogs in the fate of networks-of-networks. PMID:27841258

Greenland subglacial drainage evolution regulated by weakly connected regions of the bed

DOE PAGES

Hoffman, Matthew J.; Andrews, Lauren C.; Price, Stephen A.; ...

2016-12-19

Penetration of surface meltwater to the bed of the Greenland Ice Sheet each summer causes an initial increase in ice speed due to elevated basal water pressure, followed by slowdown in late summer that continues into fall and winter. While this seasonal pattern is commonly explained by an evolution of the subglacial drainage system from an inefficient distributed to efficient channelized configuration, mounting evidence indicates that subglacial channels are unable to explain important aspects of hydrodynamic coupling in late summer and fall. Here we use numerical models of subglacial drainage and ice flow to show that limited, gradual leakage ofmore » water and lowering of water pressure in weakly connected regions of the bed can explain the dominant features in late and post melt season ice dynamics. Finally, these results suggest that a third weakly connected drainage component should be included in the conceptual model of subglacial hydrology.« less

Greenland subglacial drainage evolution regulated by weakly connected regions of the bed

NASA Astrophysics Data System (ADS)

Hoffman, Matthew J.; Andrews, Lauren C.; Price, Stephen A.; Catania, Ginny A.; Neumann, Thomas A.; Lüthi, Martin P.; Gulley, Jason; Ryser, Claudia; Hawley, Robert L.; Morriss, Blaine

2016-12-01

Penetration of surface meltwater to the bed of the Greenland Ice Sheet each summer causes an initial increase in ice speed due to elevated basal water pressure, followed by slowdown in late summer that continues into fall and winter. While this seasonal pattern is commonly explained by an evolution of the subglacial drainage system from an inefficient distributed to efficient channelized configuration, mounting evidence indicates that subglacial channels are unable to explain important aspects of hydrodynamic coupling in late summer and fall. Here we use numerical models of subglacial drainage and ice flow to show that limited, gradual leakage of water and lowering of water pressure in weakly connected regions of the bed can explain the dominant features in late and post melt season ice dynamics. These results suggest that a third weakly connected drainage component should be included in the conceptual model of subglacial hydrology.

HEXT, a software supporting tree-based screens for hybrid taxa in multilocus data sets, and an evaluation of the homoplasy excess test.

PubMed

Schneider, Kevin; Koblmüller, Stephan; Sefc, Kristina M

2015-11-11

The homoplasy excess test (HET) is a tree-based screen for hybrid taxa in multilocus nuclear phylogenies. Homoplasy between a hybrid taxon and the clades containing the parental taxa reduces bootstrap support in the tree. The HET is based on the expectation that excluding the hybrid taxon from the data set increases the bootstrap support for the parental clades, whereas excluding non-hybrid taxa has little effect on statistical node support. To carry out a HET, bootstrap trees are calculated with taxon-jackknife data sets, that is excluding one taxon (species, population) at a time. Excess increase in bootstrap support for certain nodes upon exclusion of a particular taxon indicates the hybrid (the excluded taxon) and its parents (the clades with increased support).We introduce a new software program, hext, which generates the taxon-jackknife data sets, runs the bootstrap tree calculations, and identifies excess bootstrap increases as outlier values in boxplot graphs. hext is written in r language and accepts binary data (0/1; e.g. AFLP) as well as co-dominant SNP and genotype data.We demonstrate the usefulness of hext in large SNP data sets containing putative hybrids and their parents. For instance, using published data of the genus Vitis (~6,000 SNP loci), hext output supports V. × champinii as a hybrid between V. rupestris and V. mustangensis .With simulated SNP and AFLP data sets, excess increases in bootstrap support were not always connected with the hybrid taxon (false positives), whereas the expected bootstrap signal failed to appear on several occasions (false negatives). Potential causes for both types of spurious results are discussed.With both empirical and simulated data sets, the taxon-jackknife output generated by hext provided additional signatures of hybrid taxa, including changes in tree topology across trees, consistent effects of exclusions of the hybrid and the parent taxa, and moderate (rather than excessive) increases in bootstrap support. hext significantly facilitates the taxon-jackknife approach to hybrid taxon detection, even though the simple test for excess bootstrap increase may not reliably identify hybrid taxa in all applications.

Rational Design of Tunnel Supports: Tunnel Support Loading Caused by Rock Failure

DTIC Science & Technology

1975-05-01

dotted lines connect points indicating the magnitude of the normal force within the liner. Middle; Same as above, but with floor beam ...and foremost to include some rotational freedom at beam element nodal points that correspond to connections between steel set segments as well as...subroutine SOL during the first support connection , with beam stiffnesses calculated in FORMB. 9. The tunnel periphery displacements that

M/A-COM Linkabit Eastern Operations

DTIC Science & Technology

1983-03-31

Lincoln Laboratories speech codec for use in multimedia system development. Communication equipment included 1200-bps dial-up modems and a set of...connected to the DCN for use in[7, Page 4 general word-processing and network-testing applications.Additional modems and video terminals have also been...line 0) can be connected to a second terminal, a printer, or a modem . The standard configuration assumes this line is connected to a terminal or

A Procedure for Modeling Structural Component/Attachment Failure Using Transient Finite Element Analysis

NASA Technical Reports Server (NTRS)

Lovejoy, Andrew E.; Jegley, Dawn C. (Technical Monitor)

2007-01-01

Structures often comprise smaller substructures that are connected to each other or attached to the ground by a set of finite connections. Under static loading one or more of these connections may exceed allowable limits and be deemed to fail. Of particular interest is the structural response when a connection is severed (failed) while the structure is under static load. A transient failure analysis procedure was developed by which it is possible to examine the dynamic effects that result from introducing a discrete failure while a structure is under static load. The failure is introduced by replacing a connection load history by a time-dependent load set that removes the connection load at the time of failure. The subsequent transient response is examined to determine the importance of the dynamic effects by comparing the structural response with the appropriate allowables. Additionally, this procedure utilizes a standard finite element transient analysis that is readily available in most commercial software, permitting the study of dynamic failures without the need to purchase software specifically for this purpose. The procedure is developed and explained, demonstrated on a simple cantilever box example, and finally demonstrated on a real-world example, the American Airlines Flight 587 (AA587) vertical tail plane (VTP).

Towards affordable biomarkers of frontotemporal dementia: A classification study via network's information sharing.

PubMed

Dottori, Martin; Sedeño, Lucas; Martorell Caro, Miguel; Alifano, Florencia; Hesse, Eugenia; Mikulan, Ezequiel; García, Adolfo M; Ruiz-Tagle, Amparo; Lillo, Patricia; Slachevsky, Andrea; Serrano, Cecilia; Fraiman, Daniel; Ibanez, Agustin

2017-06-19

Developing effective and affordable biomarkers for dementias is critical given the difficulty to achieve early diagnosis. In this sense, electroencephalographic (EEG) methods offer promising alternatives due to their low cost, portability, and growing robustness. Here, we relied on EEG signals and a novel information-sharing method to study resting-state connectivity in patients with behavioral variant frontotemporal dementia (bvFTD) and controls. To evaluate the specificity of our results, we also tested Alzheimer's disease (AD) patients. The classification power of the ensuing connectivity patterns was evaluated through a supervised classification algorithm (support vector machine). In addition, we compared the classification power yielded by (i) functional connectivity, (ii) relevant neuropsychological tests, and (iii) a combination of both. BvFTD patients exhibited a specific pattern of hypoconnectivity in mid-range frontotemporal links, which showed no alterations in AD patients. These functional connectivity alterations in bvFTD were replicated with a low-density EEG setting (20 electrodes). Moreover, while neuropsychological tests yielded acceptable discrimination between bvFTD and controls, the addition of connectivity results improved classification power. Finally, classification between bvFTD and AD patients was better when based on connectivity than on neuropsychological measures. Taken together, such findings underscore the relevance of EEG measures as potential biomarker signatures for clinical settings.

Automated Segmentation of Kidneys from MR Images in Patients with Autosomal Dominant Polycystic Kidney Disease.

PubMed

Kim, Youngwoo; Ge, Yinghui; Tao, Cheng; Zhu, Jianbing; Chapman, Arlene B; Torres, Vicente E; Yu, Alan S L; Mrug, Michal; Bennett, William M; Flessner, Michael F; Landsittel, Doug P; Bae, Kyongtae T

2016-04-07

Our study developed a fully automated method for segmentation and volumetric measurements of kidneys from magnetic resonance images in patients with autosomal dominant polycystic kidney disease and assessed the performance of the automated method with the reference manual segmentation method. Study patients were selected from the Consortium for Radiologic Imaging Studies of Polycystic Kidney Disease. At the enrollment of the Consortium for Radiologic Imaging Studies of Polycystic Kidney Disease Study in 2000, patients with autosomal dominant polycystic kidney disease were between 15 and 46 years of age with relatively preserved GFRs. Our fully automated segmentation method was on the basis of a spatial prior probability map of the location of kidneys in abdominal magnetic resonance images and regional mapping with total variation regularization and propagated shape constraints that were formulated into a level set framework. T2-weighted magnetic resonance image sets of 120 kidneys were selected from 60 patients with autosomal dominant polycystic kidney disease and divided into the training and test datasets. The performance of the automated method in reference to the manual method was assessed by means of two metrics: Dice similarity coefficient and intraclass correlation coefficient of segmented kidney volume. The training and test sets were swapped for crossvalidation and reanalyzed. Successful segmentation of kidneys was performed with the automated method in all test patients. The segmented kidney volumes ranged from 177.2 to 2634 ml (mean, 885.4±569.7 ml). The mean Dice similarity coefficient ±SD between the automated and manual methods was 0.88±0.08. The mean correlation coefficient between the two segmentation methods for the segmented volume measurements was 0.97 (P<0.001 for each crossvalidation set). The results from the crossvalidation sets were highly comparable. We have developed a fully automated method for segmentation of kidneys from abdominal magnetic resonance images in patients with autosomal dominant polycystic kidney disease with varying kidney volumes. The performance of the automated method was in good agreement with that of manual method. Copyright © 2016 by the American Society of Nephrology.

Ion Propulsion Thruster Including a Plurality of Ion Optic Electrode Pairs

NASA Technical Reports Server (NTRS)

Patterson, Michael J. (Inventor)

2016-01-01

Ion optics for use in a conventional or annular or other shaped ion thruster are disclosed including a plurality of planar, spaced apart ion optic electrode pairs sized to include a diameter smaller than the diameter of thruster exhaust and retained in, on or otherwise associated with a frame across the thruster exhaust. An electrical connection may be provided for establishing electrical connectivity among a set of first upstream electrodes and an electrical connection may be provided for establishing electrical connectivity among the second downstream electrodes.

Watershed erosion modeling using the probability of sediment connectivity in a gently rolling system

NASA Astrophysics Data System (ADS)

Mahoney, David Tyler; Fox, James Forrest; Al Aamery, Nabil

2018-06-01

Sediment connectivity has been shown in recent years to explain how the watershed configuration controls sediment transport. However, we find no studies develop a watershed erosion modeling framework based on sediment connectivity, and few, if any, studies have quantified sediment connectivity for gently rolling systems. We develop a new predictive sediment connectivity model that relies on the intersecting probabilities for sediment supply, detachment, transport, and buffers to sediment transport, which is integrated in a watershed erosion model framework. The model predicts sediment flux temporally and spatially across a watershed using field reconnaissance results, a high-resolution digital elevation models, a hydrologic model, and shear-based erosion formulae. Model results validate the capability of the model to predict erosion pathways causing sediment connectivity. More notably, disconnectivity dominates the gently rolling watershed across all morphologic levels of the uplands, including, microtopography from low energy undulating surfaces across the landscape, swales and gullies only active in the highest events, karst sinkholes that disconnect drainage areas, and floodplains that de-couple the hillslopes from the stream corridor. Results show that sediment connectivity is predicted for about 2% or more the watershed's area 37 days of the year, with the remaining days showing very little or no connectivity. Only 12.8 ± 0.7% of the gently rolling watershed shows sediment connectivity on the wettest day of the study year. Results also highlight the importance of urban/suburban sediment pathways in gently rolling watersheds, and dynamic and longitudinal distributions of sediment connectivity might be further investigated in future work. We suggest the method herein provides the modeler with an added tool to account for sediment transport criteria and has the potential to reduce computational costs in watershed erosion modeling.

What are the Ingredients of a Scientifically and Policy-Relevant Hydrologic Connectivity Metric?

NASA Astrophysics Data System (ADS)

Ali, G.; English, C.; McCullough, G.; Stainton, M.

2014-12-01

While the concept of hydrologic connectivity is of significant importance to both researchers and policy makers, there is no consensus on how to express it in quantitative terms. This lack of consensus was further exacerbated by recent rulings of the U.S. Supreme Court that rely on the idea of "significant nexuses": critical degrees of landscape connectivity now have to be demonstrated to warrant environmental protection under the Clean Water Act. Several indicators of connectivity have been suggested in the literature, but they are often computationally intensive and require soil water content information, a requirement that makes them inapplicable over large, data-poor areas for which management decisions are needed. Here our objective was to assess the extent to which the concept of connectivity could become more operational by: 1) drafting a list of potential, watershed-scale connectivity metrics; 2) establishing a list of criteria for ranking the performance of those metrics; 3) testing them in various landscapes. Our focus was on a dozen agricultural Prairie watersheds where the interaction between near-level topography, perennial and intermittent streams, pothole wetlands and man-made drains renders the estimation of connectivity difficult. A simple procedure was used to convert RADARSAT images, collected between 1997 and 2011, into binary maps of saturated versus non-saturated areas. Several pattern-based and graph-theoretic metrics were then computed for a dynamic assessment of connectivity. The metrics performance was compared with regards to their sensitivity to antecedent precipitation, their correlation with watershed discharge, and their ability to portray aggregation effects. Results show that no single connectivity metric could satisfy all our performance criteria. Graph-theoretic metrics however seemed to perform better in pothole-dominated watersheds, thus highlighting the need for region-specific connectivity assessment frameworks.

Sediment Connectivity and Transport Pathways in Tidal Inlets: a Conceptual Framework with Application to Ameland Inlet

NASA Astrophysics Data System (ADS)

Pearson, S.; van Prooijen, B. C.; Zheng Bing, W.; Bak, J.

2017-12-01

Predicting the response of tidal inlets and adjacent coastlines to sea level rise and anthropogenic interventions (e.g. sand nourishments) requires understanding of sediment transport pathways. These pathways are strongly dependent on hydrodynamic forcing, grain size, underlying morphology, and the timescale considered. To map and describe these pathways, we considered the concept of sediment connectivity, which quantifies the degree to which sediment transport pathways link sources to receptors. In this study we established a framework for understanding sediment transport pathways in coastal environments, using Ameland Inlet in the Dutch Wadden Sea as a basis. We used the Delft3D morphodynamic model to assess the fate of sediment as it moved between specific morphological units defined in the model domain. Simulation data was synthesized in a graphical network and then graph theory used to analyze connectivity at different space and time scales. At decadal time scales, fine and very fine sand (<250μm) have greater connectivity with receptor areas further away from their sources. Conversely, medium sand (>250μm) shows lower connectivity, even in more energetic areas. Greater sediment connectivity was found under the influence of wind and waves when compared to purely tidal forcing. Connectivity shows considerable spatial variation in cross shore and alongshore directions, depending on proximity to the inlet and dominant wave direction. Furthermore, connectivity generally increases at longer timescales. Asymmetries in connectivity (i.e. unidirectional transport) can be used to explain long-term erosional or depositional trends. As such, an understanding of sediment connectivity as a function of grain size could yield useful insights for resolving sediment transport pathways and the fate of a nourishment in coastal environments.

On Efficient Deployment of Wireless Sensors for Coverage and Connectivity in Constrained 3D Space.

PubMed

Wu, Chase Q; Wang, Li

2017-10-10

Sensor networks have been used in a rapidly increasing number of applications in many fields. This work generalizes a sensor deployment problem to place a minimum set of wireless sensors at candidate locations in constrained 3D space to k -cover a given set of target objects. By exhausting the combinations of discreteness/continuousness constraints on either sensor locations or target objects, we formulate four classes of sensor deployment problems in 3D space: deploy sensors at Discrete/Continuous Locations (D/CL) to cover Discrete/Continuous Targets (D/CT). We begin with the design of an approximate algorithm for DLDT and then reduce DLCT, CLDT, and CLCT to DLDT by discretizing continuous sensor locations or target objects into a set of divisions without sacrificing sensing precision. Furthermore, we consider a connected version of each problem where the deployed sensors must form a connected network, and design an approximation algorithm to minimize the number of deployed sensors with connectivity guarantee. For performance comparison, we design and implement an optimal solution and a genetic algorithm (GA)-based approach. Extensive simulation results show that the proposed deployment algorithms consistently outperform the GA-based heuristic and achieve a close-to-optimal performance in small-scale problem instances and a significantly superior overall performance than the theoretical upper bound.

Viewing socio-affective stimuli increases connectivity within an extended default mode network.

PubMed

Göttlich, Martin; Ye, Zheng; Rodriguez-Fornells, Antoni; Münte, Thomas F; Krämer, Ulrike M

2017-03-01

Empathy is an essential ability for prosocial behavior. Previous imaging studies identified a number of brain regions implicated in affective and cognitive aspects of empathy. In this study, we investigated the neural correlates of empathy from a network perspective using graph theory and beta-series correlations. Two independent data sets were acquired using the same paradigm that elicited empathic responses to socio-affective stimuli. One data set was used to define the network nodes and modular structure, the other data set was used to investigate the effects of emotional versus neutral stimuli on network connectivity. Emotional relative to neutral stimuli increased connectivity between 74 nodes belonging to different networks. Most of these nodes belonged to an extended default mode network (eDMN). The other nodes belonged to a cognitive control network or visual networks. Within the eDMN, posterior STG/TPJ regions were identified as provincial hubs. The eDMN also showed stronger connectivity to the cognitive control network encompassing lateral PFC regions. Connector hubs between the two networks were posterior cingulate cortex and ventrolateral PFC. This stresses the advantage of a network approach as regions similarly modulated by task conditions can be dissociated into distinct networks and regions crucial for network integration can be identified. Copyright © 2017 Elsevier Inc. All rights reserved.

On chemical distances and shape theorems in percolation models with long-range correlations

NASA Astrophysics Data System (ADS)

Drewitz, Alexander; Ráth, Balázs; Sapozhnikov, Artëm

2014-08-01

In this paper, we provide general conditions on a one parameter family of random infinite subsets of {{Z}}^d to contain a unique infinite connected component for which the chemical distances are comparable to the Euclidean distance. In addition, we show that these conditions also imply a shape theorem for the corresponding infinite connected component. By verifying these conditions for specific models, we obtain novel results about the structure of the infinite connected component of the vacant set of random interlacements and the level sets of the Gaussian free field. As a byproduct, we obtain alternative proofs to the corresponding results for random interlacements in the work of Černý and Popov ["On the internal distance in the interlacement set," Electron. J. Probab. 17(29), 1-25 (2012)], and while our main interest is in percolation models with long-range correlations, we also recover results in the spirit of the work of Antal and Pisztora ["On the chemical distance for supercritical Bernoulli percolation," Ann Probab. 24(2), 1036-1048 (1996)] for Bernoulli percolation. Finally, as a corollary, we derive new results about the (chemical) diameter of the largest connected component in the complement of the trace of the random walk on the torus.

"That's Not Quite the Way We See It": The Epistemological Challenge of Visual Data

ERIC Educational Resources Information Center

Wall, Kate; Higgins, Steve; Hall, Elaine; Woolner, Pam

2013-01-01

In research textbooks, and much of the research practice, they describe, qualitative processes and interpretivist epistemologies tend to dominate visual methodology. This article challenges the assumptions behind this dominance. Using exemplification from three existing visual data sets produced through one large education research project, this…