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Sample records for dynamics features caused

  1. Dynamic features of combustion

    NASA Technical Reports Server (NTRS)

    Oppenheim, A. K.

    1985-01-01

    The dynamic features of combustion are discussed for four important cases: ignition, inflammation, explosion, and detonation. Ignition, the initiation of a self-sustained exothermic process, is considered in the simplest case of a closed thermodynamic system and its stochastic distribution. Inflammation, the initiation and propagation of self-sustained flames, is presented for turbulent flow. Explosion, the dynamic effects caused by the deposition of exothermic energy in a compressible medium, is illustrated by self-similar blast waves with energy deposition at the front and the adiabatic non-self-similar wave. Detonation, the most comprehensive illustration of all the dynamic effects of combustion, is discussed with a phenomenological account of the development and structure of the wave.

  2. Special Features of Galactic Dynamics

    NASA Astrophysics Data System (ADS)

    Efthymiopoulos, Christos; Voglis, Nikos; Kalapotharakos, Constantinos

    This is an introductory article to some basic notions and currently open problems of galactic dynamics. The focus is on topics mostly relevant to the so-called `new methods' of celestial mechanics or Hamiltonian dynamics, as applied to the ellipsoidal components of galaxies, i.e., to the elliptical galaxies and to the dark halos and bulges of disk galaxies. Traditional topics such as Jeans theorem, the role of a `third integral' of motion, Nekhoroshev theory, violent relaxation, and the statistical mechanics of collisionless stellar systems are first discussed. The emphasis is on modern extrapolations of these old topics. Recent results from orbital and global dynamical studies of galaxies are then shortly reviewed. The role of various families of orbits in supporting self-consistency, as well as the role of chaos in galaxies, are stressed. A description is then given of the main numerical techniques of integration of the N-body problem in the framework of stellar dynamics and of the results obtained via N-Body experiments. A final topic is the secular evolution and self-organization of galactic systems.

  3. Sedimentation dynamics about salt features

    SciTech Connect

    Lowrie, A.; Blake, D.W.

    1985-02-01

    Detailed side-scan sonar and gridded bathymetric surveys on continental margins reveal the existence of numerous submarine canyons. Recently published compilations of current velocities in submarine canyons indicate that alternating and undirectionaly flows often exceed 20-30 cm/sec with peak velocities ranging from 70 to 100 cm/sec. Current meters attached to the ocean floor have been lost at current velocities of 190 cm/sec. Such velocities are ample to transport sand-size sediments. The results of DSDP Leg 96 show the existence of massive sands and gravels on the Louisiana slope, deposited during the last glacial advance. Thus, present physical oceanographic data may be an analog to conditions during glacially induced lowered sea levels. Salt ridges and domes underlie much of the Louisiana slope, determining morphology. Submarine canyons lace the slope. Given a prograding shelf, the net sediment transport routes will be down the submarine canyons. Sediment deposition patterns around the salt ridges and domes include parallel-bedded foredrifts on the upslope side, lee drifts on the downslope side, and moats along the lateral flanks of the salt features. Major differences exist between the sedimentation patterns around a ridge and a dome. The size and shape of the flow pattern will determine whether there can be a flow over the salt feature with a resulting turbulent wave that may influence sedimentation. Sedimentation patterns about salt features on the present slope should be applicable to similar paleoenvironments.

  4. Encoding Cortical Dynamics in Sparse Features

    PubMed Central

    Khan, Sheraz; Lefèvre, Julien; Baillet, Sylvain; Michmizos, Konstantinos P.; Ganesan, Santosh; Kitzbichler, Manfred G.; Zetino, Manuel; Hämäläinen, Matti S.; Papadelis, Christos; Kenet, Tal

    2014-01-01

    Distributed cortical solutions of magnetoencephalography (MEG) and electroencephalography (EEG) exhibit complex spatial and temporal dynamics. The extraction of patterns of interest and dynamic features from these cortical signals has so far relied on the expertise of investigators. There is a definite need in both clinical and neuroscience research for a method that will extract critical features from high-dimensional neuroimaging data in an automatic fashion. We have previously demonstrated the use of optical flow techniques for evaluating the kinematic properties of motion field projected on non-flat manifolds like in a cortical surface. We have further extended this framework to automatically detect features in the optical flow vector field by using the modified and extended 2-Riemannian Helmholtz–Hodge decomposition (HHD). Here, we applied these mathematical models on simulation and MEG data recorded from a healthy individual during a somatosensory experiment and an epilepsy pediatric patient during sleep. We tested whether our technique can automatically extract salient dynamical features of cortical activity. Simulation results indicated that we can precisely reproduce the simulated cortical dynamics with HHD; encode them in sparse features and represent the propagation of brain activity between distinct cortical areas. Using HHD, we decoded the somatosensory N20 component into two HHD features and represented the dynamics of brain activity as a traveling source between two primary somatosensory regions. In the epilepsy patient, we displayed the propagation of the epileptic activity around the margins of a brain lesion. Our findings indicate that HHD measures computed from cortical dynamics can: (i) quantitatively access the cortical dynamics in both healthy and disease brain in terms of sparse features and dynamic brain activity propagation between distinct cortical areas, and (ii) facilitate a reproducible, automated analysis of experimental and clinical

  5. Encoding cortical dynamics in sparse features.

    PubMed

    Khan, Sheraz; Lefèvre, Julien; Baillet, Sylvain; Michmizos, Konstantinos P; Ganesan, Santosh; Kitzbichler, Manfred G; Zetino, Manuel; Hämäläinen, Matti S; Papadelis, Christos; Kenet, Tal

    2014-01-01

    Distributed cortical solutions of magnetoencephalography (MEG) and electroencephalography (EEG) exhibit complex spatial and temporal dynamics. The extraction of patterns of interest and dynamic features from these cortical signals has so far relied on the expertise of investigators. There is a definite need in both clinical and neuroscience research for a method that will extract critical features from high-dimensional neuroimaging data in an automatic fashion. We have previously demonstrated the use of optical flow techniques for evaluating the kinematic properties of motion field projected on non-flat manifolds like in a cortical surface. We have further extended this framework to automatically detect features in the optical flow vector field by using the modified and extended 2-Riemannian Helmholtz-Hodge decomposition (HHD). Here, we applied these mathematical models on simulation and MEG data recorded from a healthy individual during a somatosensory experiment and an epilepsy pediatric patient during sleep. We tested whether our technique can automatically extract salient dynamical features of cortical activity. Simulation results indicated that we can precisely reproduce the simulated cortical dynamics with HHD; encode them in sparse features and represent the propagation of brain activity between distinct cortical areas. Using HHD, we decoded the somatosensory N20 component into two HHD features and represented the dynamics of brain activity as a traveling source between two primary somatosensory regions. In the epilepsy patient, we displayed the propagation of the epileptic activity around the margins of a brain lesion. Our findings indicate that HHD measures computed from cortical dynamics can: (i) quantitatively access the cortical dynamics in both healthy and disease brain in terms of sparse features and dynamic brain activity propagation between distinct cortical areas, and (ii) facilitate a reproducible, automated analysis of experimental and clinical

  6. Feature extraction for structural dynamics model validation

    SciTech Connect

    Hemez, Francois; Farrar, Charles; Park, Gyuhae; Nishio, Mayuko; Worden, Keith; Takeda, Nobuo

    2010-11-08

    This study focuses on defining and comparing response features that can be used for structural dynamics model validation studies. Features extracted from dynamic responses obtained analytically or experimentally, such as basic signal statistics, frequency spectra, and estimated time-series models, can be used to compare characteristics of structural system dynamics. By comparing those response features extracted from experimental data and numerical outputs, validation and uncertainty quantification of numerical model containing uncertain parameters can be realized. In this study, the applicability of some response features to model validation is first discussed using measured data from a simple test-bed structure and the associated numerical simulations of these experiments. issues that must be considered were sensitivity, dimensionality, type of response, and presence or absence of measurement noise in the response. Furthermore, we illustrate a comparison method of multivariate feature vectors for statistical model validation. Results show that the outlier detection technique using the Mahalanobis distance metric can be used as an effective and quantifiable technique for selecting appropriate model parameters. However, in this process, one must not only consider the sensitivity of the features being used, but also correlation of the parameters being compared.

  7. Geochemical dynamics in selected Yellowstone hydrothermal features

    NASA Astrophysics Data System (ADS)

    Druschel, G.; Kamyshny, A.; Findlay, A.; Nuzzio, D.

    2010-12-01

    Yellowstone National Park has a wide diversity of thermal features, and includes springs with a range of pH conditions that significantly impact sulfur speciation. We have utilized a combination of voltammetric and spectroscopic techniques to characterize the intermediate sulfur chemistry of Cinder Pool, Evening Primrose, Ojo Caliente, Frying Pan, Azure, and Dragon thermal springs. These measurements additionally have demonstrated the geochemical dynamics inherent in these systems; significant variability in chemical speciation occur in many of these thermal features due to changes in gas supply rates, fluid discharge rates, and thermal differences that occur on second time scales. The dynamics of the geochemical settings shown may significantly impact how microorganisms interact with the sulfur forms in these systems.

  8. Persistent topological features of dynamical systems

    NASA Astrophysics Data System (ADS)

    Maletić, Slobodan; Zhao, Yi; Rajković, Milan

    2016-05-01

    Inspired by an early work of Muldoon et al., Physica D 65, 1-16 (1993), we present a general method for constructing simplicial complex from observed time series of dynamical systems based on the delay coordinate reconstruction procedure. The obtained simplicial complex preserves all pertinent topological features of the reconstructed phase space, and it may be analyzed from topological, combinatorial, and algebraic aspects. In focus of this study is the computation of homology of the invariant set of some well known dynamical systems that display chaotic behavior. Persistent homology of simplicial complex and its relationship with the embedding dimensions are examined by studying the lifetime of topological features and topological noise. The consistency of topological properties for different dynamic regimes and embedding dimensions is examined. The obtained results shed new light on the topological properties of the reconstructed phase space and open up new possibilities for application of advanced topological methods. The method presented here may be used as a generic method for constructing simplicial complex from a scalar time series that has a number of advantages compared to the mapping of the same time series to a complex network.

  9. Persistent topological features of dynamical systems.

    PubMed

    Maletić, Slobodan; Zhao, Yi; Rajković, Milan

    2016-05-01

    Inspired by an early work of Muldoon et al., Physica D 65, 1-16 (1993), we present a general method for constructing simplicial complex from observed time series of dynamical systems based on the delay coordinate reconstruction procedure. The obtained simplicial complex preserves all pertinent topological features of the reconstructed phase space, and it may be analyzed from topological, combinatorial, and algebraic aspects. In focus of this study is the computation of homology of the invariant set of some well known dynamical systems that display chaotic behavior. Persistent homology of simplicial complex and its relationship with the embedding dimensions are examined by studying the lifetime of topological features and topological noise. The consistency of topological properties for different dynamic regimes and embedding dimensions is examined. The obtained results shed new light on the topological properties of the reconstructed phase space and open up new possibilities for application of advanced topological methods. The method presented here may be used as a generic method for constructing simplicial complex from a scalar time series that has a number of advantages compared to the mapping of the same time series to a complex network. PMID:27249945

  10. Dynamic feature analysis in bidirectional pedestrian flows

    NASA Astrophysics Data System (ADS)

    Xiao-Xia, Yang; Winnie, Daamen; Serge, Paul Hoogendoorn; Hai-Rong, Dong; Xiu-Ming, Yao

    2016-02-01

    Analysis of dynamic features of pedestrian flows is one of the most exciting topics in pedestrian dynamics. This paper focuses on the effect of homogeneity and heterogeneity in three parameters of the social force model, namely desired velocity, reaction time, and body size, on the moving dynamics of bidirectional pedestrian flows in the corridors. The speed and its deviation in free flows are investigated. Simulation results show that the homogeneous higher desired speed which is less than a critical threshold, shorter reaction time or smaller body size results in higher speed of flows. The free dynamics is more sensitive to the heterogeneity in desired speed than that in reaction time or in body size. In particular, an inner lane formation is observed in normal lanes. Furthermore, the breakdown probability and the start time of breakdown are focused on. This study reveals that the sizes of homogeneous desired speed, reaction time or body size play more important roles in affecting the breakdown than the heterogeneities in these three parameters do. Project supported jointly by the National Natural Science Foundation of China (Grant No. 61233001) and the Fundamental Research Funds for Central Universities of China (Grant No. 2013JBZ007).

  11. Dynamic Features in and nearby a Prominence

    NASA Technical Reports Server (NTRS)

    Kucera, T.; Landi, E.

    2006-01-01

    We will discuss the thermal and dynamic properties of dynamic structures in and around a prominence channel observed on the limb on 17 April 2003. Observations were taken with the Solar and Heliospheric Observatory's Solar Ultraviolet Measurements of Emitted Radiation (SOHO/SUMER) in lines formed at temperatures from 80,000 to 1.6 million K. The instrument was pointed to a single location and took a series of 90 s exposures. Two-dimensional context was provided by the Transition Region and Coronal Explorer (TRACE) in the UV and EUV and by the Kanzelhohe Solar Observatory in H-alpha. Two dynamic features were studied in depth: a prominence activation and repeated motions in a loop nearby the prominence. We were able to calculate three-dimensional geometries and trajectories, differential emission measure, and limits on the average density, kinetic and thermal energies. These observations provide important tests for models of dynamics in prominences and cool (approx.10(exp 5) K) loops.

  12. Dynamics of low capillary number interfaces moving through sharp features

    NASA Astrophysics Data System (ADS)

    Reddy, Shravanthi; Schunk, P. Randall; Bonnecaze, Roger T.

    2005-12-01

    The success of any nanoimprint process depends upon its ability to exactly reproduce the template pattern. Thus, complete filling of recessed features in the template is an important issue that is controlled by the dynamics of the flow through these sharp structures. At these small scales, capillary forces are large and must be included in the fluid flow model. The mechanism of interface advancement at low capillary number through sharp rectangular features is useful for understanding how and why features fill or trap air. In this study we present a two-dimensional simulation of this feature filling to capture the details of the process, including the viscous and capillary effects. Fluid is injected into the channel between the template and substrate, where the fluid-air interface soon encounters a rectangular feature with some height greater than the channel gap. As the fluid advances through the channel, the shape of the interface is a circular arc due to the strong capillary forces. The interface maintains this circular arc as it negotiates the first sharp corner of the feature; the upper contact line effectively pins to the initial corner of the feature as it moves around this corner, during which time the lower contact line continues to advance forward along the substrate surface, causing the interface to stretch. For sufficiently wide or shallow features, once the upper contact line has negotiated the first corner and has moved vertically up the inner wall of the feature, it must move through the top corner of the feature. At this point the interface undergoes a rapid reconfiguration from a high surface area circular arc to a lower surface area circular arc inside the feature. Alternatively, for narrow or high features, the stretched interface can catch on the far, final corner of the feature, trapping air inside the feature and preventing filling. The conditions for filling are studied parametrically for a variety of wetting contact angles and feature

  13. [Epidemiological features and causes of railway traffic accidents].

    PubMed

    Zhou, D S

    1991-01-01

    This article reports on epidemiological features of railway traffic accidents and factors influencing traffic safety. An analysis of various kinds of railway traffic accidents over 30 years in Nanjing Railway Branch, Showed that railway traffic accidents have become a sort of modern social disease, and had particular epidemiological features. The peak of the epidemic curve appeared cyclically and had a close relation to social disturbances, Frequency of accident occurrence was the highest in the first season (period of spring transport) and the third season (period of high temperature) of the year thus most accidents happen in February and August. Most accidents occurred on Fridays and least on Mondays. Distribution of accidents had obvious "antenna" phenomenon in round graph which had a 24-hour cycle. Analysing the multiple factors influencing traffic safety, the results showed that the upper-limit-age of a train driver should not be more than 50 years old; The phenomenon "bathtub" between personage accident rate and age must be taken seriously. More attention should be paid to the psychological aspects when recruiting train drivers. In our country, it is urgent to set up standard of psychomovement function for choosing train locomotive drivers. Fatigue was one of the direct causes resulting in accident occurrences. No statistical correlation was found between biorhythm and accident occurrence. PMID:2036908

  14. Interleukin-11 alters placentation and causes preeclampsia features in mice

    PubMed Central

    Winship, Amy L.; Koga, Kaori; Menkhorst, Ellen; Van Sinderen, Michelle; Rainczuk, Katarzyna; Nagai, Miwako; Cuman, Carly; Yap, Joanne; Zhang, Jian-Guo; Simmons, David; Young, Morag J.; Dimitriadis, Evdokia

    2015-01-01

    Preeclampsia (PE) is a pregnancy-specific disorder characterized by hypertension and proteinuria after 20 wk gestation. Abnormal extravillous trophoblast (EVT) invasion and remodeling of uterine spiral arterioles is thought to contribute to PE development. Interleukin-11 (IL11) impedes human EVT invasion in vitro and is elevated in PE decidua in women. We demonstrate that IL11 administered to mice causes development of PE features. Immunohistochemistry shows IL11 compromises trophoblast invasion, spiral artery remodeling, and placentation, leading to increased systolic blood pressure (SBP), proteinuria, and intrauterine growth restriction, although nonpregnant mice were unaffected. Real-time PCR array analysis identified pregnancy-associated plasma protein A2 (PAPPA2), associated with PE in women, as an IL11 regulated target. IL11 increased PAPPA2 serum and placental tissue levels in mice. In vitro, IL11 compromised primary human EVT invasion, whereas siRNA knockdown of PAPPA2 alleviated the effect. Genes regulating uterine natural killer (uNK) recruitment and differentiation were down-regulated and uNK cells were reduced after IL11 treatment in mice. IL11 withdrawal in mice at onset of PE features reduced SBP and proteinuria to control levels and alleviated placental labyrinth defects. In women, placental IL11 immunostaining levels increased in PE pregnancies and in serum collected from women before development of early-onset PE, shown by ELISA. These results indicate that elevated IL11 levels result in physiological changes at the maternal–fetal interface, contribute to abnormal placentation, and lead to the development of PE. Targeting placental IL11 may provide a new treatment option for PE. PMID:26655736

  15. Interleukin-11 alters placentation and causes preeclampsia features in mice.

    PubMed

    Winship, Amy L; Koga, Kaori; Menkhorst, Ellen; Van Sinderen, Michelle; Rainczuk, Katarzyna; Nagai, Miwako; Cuman, Carly; Yap, Joanne; Zhang, Jian-Guo; Simmons, David; Young, Morag J; Dimitriadis, Evdokia

    2015-12-29

    Preeclampsia (PE) is a pregnancy-specific disorder characterized by hypertension and proteinuria after 20 wk gestation. Abnormal extravillous trophoblast (EVT) invasion and remodeling of uterine spiral arterioles is thought to contribute to PE development. Interleukin-11 (IL11) impedes human EVT invasion in vitro and is elevated in PE decidua in women. We demonstrate that IL11 administered to mice causes development of PE features. Immunohistochemistry shows IL11 compromises trophoblast invasion, spiral artery remodeling, and placentation, leading to increased systolic blood pressure (SBP), proteinuria, and intrauterine growth restriction, although nonpregnant mice were unaffected. Real-time PCR array analysis identified pregnancy-associated plasma protein A2 (PAPPA2), associated with PE in women, as an IL11 regulated target. IL11 increased PAPPA2 serum and placental tissue levels in mice. In vitro, IL11 compromised primary human EVT invasion, whereas siRNA knockdown of PAPPA2 alleviated the effect. Genes regulating uterine natural killer (uNK) recruitment and differentiation were down-regulated and uNK cells were reduced after IL11 treatment in mice. IL11 withdrawal in mice at onset of PE features reduced SBP and proteinuria to control levels and alleviated placental labyrinth defects. In women, placental IL11 immunostaining levels increased in PE pregnancies and in serum collected from women before development of early-onset PE, shown by ELISA. These results indicate that elevated IL11 levels result in physiological changes at the maternal-fetal interface, contribute to abnormal placentation, and lead to the development of PE. Targeting placental IL11 may provide a new treatment option for PE. PMID:26655736

  16. Fecal incontinence in men: Causes and clinical and manometric features

    PubMed Central

    Muñoz-Yagüe, Teresa; Solís-Muñoz, Pablo; Ciriza de los Ríos, Constanza; Muñoz-Garrido, Francisco; Vara, Jesús; Solís-Herruzo, José Antonio

    2014-01-01

    AIM: To determine the causes and characteristics of fecal incontinence in men and to compare these features with those presented by a group of women with the same problem. METHODS: We analyzed the medical history, clinical and manometric data from 119 men with fecal incontinence studied in our unit and compared these data with those obtained from 645 women studied for the same problem. Response to treatment was evaluated after 6 mo of follow-up. RESULTS: Fifteen percent of patients studied in our unit for fecal incontinence were male. Men took longer than women before asking for medical help. Ano-rectal surgery was the most common risk factor for men related to fecal incontinence. Chronic diarrhea was present in more than 40% of patients in both groups. Decreased resting and external anal sphincter pressures were more frequent in women. No significant differences existed between the sexes regarding rectal sensitivity and recto-anal inhibitory reflex. In 17.8% of men, all presenting soiling, manometric findings did not justify fecal incontinence. Response to treatment was good in both groups, as 80.4% of patients improved and fecal incontinence disappeared in 13.2% of them. CONCLUSION: In our series, it was common that men waited longer in seeking medical help for fecal incontinence. Ano-rectal surgery was the major cause of this problem. Chronic diarrhea was a predisposing factor in both sexes. Manometric differences between groups were limited to an increased frequency of hypotony of the external anal sphincter in women. Fecal incontinence was controllable in most patients. PMID:24976729

  17. Geomagnetic Disturbances Caused by Internal Atmospheric Dynamics

    NASA Technical Reports Server (NTRS)

    Sonneman, G.

    1984-01-01

    It is commonly believed that geomagnetic disturbances are caused by external influences connected with the solar wind. The 27-day recurrence of perturbations seems to be a strong hint for this interaction. But frequently geomagnetic disturbances occur without any relation to sunspot numbers or radiowave fluxes. This was one of the reasons for introducing hypothetical M-regions on the Sun and their relation to solar wind activities. Only one half of the variance of the geomagnetic AL-index could be related to the solar wind. Therefore it is concluded that internal processes of the magnetosphere were responsible for additional geomagnetic activity. Arguments, which might lead to the suggestion of geomagnetic disturbances as being caused by internal atmospheric dynamics are discussed and a rather preliminary scenario of those processes is proposed.

  18. Dynamics of cloud features on Uranus

    NASA Astrophysics Data System (ADS)

    Sromovsky, L. A.; Fry, P. M.

    2005-12-01

    Near-infrared adaptive optics imaging of Uranus by the Keck 2 telescope during 2003 and 2004 has revealed numerous discrete cloud features, 70 of which were used to extend the zonal wind profile of Uranus up to 60° N. We confirmed the presence of a north-south asymmetry in the circulation [Karkoschka, E., 1998. Science 280, 570-572], and improved its characterization. We found no clear indication of long term change in wind speed between 1986 and 2004, although results of Hammel et al. [Hammel, H.B., Rages, K., Lockwood, G.W., Karkoschka, E., de Pater, I., 2001. Icarus 153, 229-235] based on 2001 HST and Keck observations average ˜10 m/s less westward than earlier and later results, and 2003 observations by Hammel et al. [Hammel, H.B., de Pater, I., Gibbard, S., Lockwood, G.W., Rages, K., 2005. Icarus 175, 534-545] show increased wind speeds near 45° N, which we do not see in our 2003-2004 observations. We observed a wide range of lifetimes for discrete cloud features: some features evolve within ˜1 h, many have persisted at least one month, and one feature near 34° S (termed S34) seems to have persisted for nearly two decades, a conclusion derived with the help of Voyager 2 and HST observations. S34 oscillates in latitude between 32° S and 36.5° S, with a period of ˜1000 days, which may be a result of a non-barotropic Rossby wave. It also varied its longitudinal drift rate between -20°/day and -31°/day in approximate accord with the latitudinal gradient in the zonal wind profile, exhibiting behavior similar to that of the DS2 feature observed on Neptune [Sromovsky, L.A., Limaye, S.S., Fry, P.M., 1993. Icarus 105, 110-141]. S34 also exhibits a superimposed rapid oscillation with an amplitude of 0.57° in latitude and period of 0.7 days, which is approximately consistent with an inertial oscillation.

  19. The relationship between 2D static features and 2D dynamic features used in gait recognition

    NASA Astrophysics Data System (ADS)

    Alawar, Hamad M.; Ugail, Hassan; Kamala, Mumtaz; Connah, David

    2013-05-01

    In most gait recognition techniques, both static and dynamic features are used to define a subject's gait signature. In this study, the existence of a relationship between static and dynamic features was investigated. The correlation coefficient was used to analyse the relationship between the features extracted from the "University of Bradford Multi-Modal Gait Database". This study includes two dimensional dynamic and static features from 19 subjects. The dynamic features were compromised of Phase-Weighted Magnitudes driven by a Fourier Transform of the temporal rotational data of a subject's joints (knee, thigh, shoulder, and elbow). The results concluded that there are eleven pairs of features that are considered significantly correlated with (p<0.05). This result indicates the existence of a statistical relationship between static and dynamics features, which challenges the results of several similar studies. These results bare great potential for further research into the area, and would potentially contribute to the creation of a gait signature using latent data.

  20. Propagation dynamics on networks featuring complex topologies

    NASA Astrophysics Data System (ADS)

    Hébert-Dufresne, Laurent; Noël, Pierre-André; Marceau, Vincent; Allard, Antoine; Dubé, Louis J.

    2010-09-01

    Analytical description of propagation phenomena on random networks has flourished in recent years, yet more complex systems have mainly been studied through numerical means. In this paper, a mean-field description is used to coherently couple the dynamics of the network elements (such as nodes, vertices, individuals, etc.) on the one hand and their recurrent topological patterns (such as subgraphs, groups, etc.) on the other hand. In a susceptible-infectious-susceptible (SIS) model of epidemic spread on social networks with community structure, this approach yields a set of ordinary differential equations for the time evolution of the system, as well as analytical solutions for the epidemic threshold and equilibria. The results obtained are in good agreement with numerical simulations and reproduce the behavior of random networks in the appropriate limits which highlights the influence of topology on the processes. Finally, it is demonstrated that our model predicts higher epidemic thresholds for clustered structures than for equivalent random topologies in the case of networks with zero degree correlation.

  1. Speech dereverberation for enhancement and recognition using dynamic features constrained deep neural networks and feature adaptation

    NASA Astrophysics Data System (ADS)

    Xiao, Xiong; Zhao, Shengkui; Ha Nguyen, Duc Hoang; Zhong, Xionghu; Jones, Douglas L.; Chng, Eng Siong; Li, Haizhou

    2016-01-01

    This paper investigates deep neural networks (DNN) based on nonlinear feature mapping and statistical linear feature adaptation approaches for reducing reverberation in speech signals. In the nonlinear feature mapping approach, DNN is trained from parallel clean/distorted speech corpus to map reverberant and noisy speech coefficients (such as log magnitude spectrum) to the underlying clean speech coefficients. The constraint imposed by dynamic features (i.e., the time derivatives of the speech coefficients) are used to enhance the smoothness of predicted coefficient trajectories in two ways. One is to obtain the enhanced speech coefficients with a least square estimation from the coefficients and dynamic features predicted by DNN. The other is to incorporate the constraint of dynamic features directly into the DNN training process using a sequential cost function. In the linear feature adaptation approach, a sparse linear transform, called cross transform, is used to transform multiple frames of speech coefficients to a new feature space. The transform is estimated to maximize the likelihood of the transformed coefficients given a model of clean speech coefficients. Unlike the DNN approach, no parallel corpus is used and no assumption on distortion types is made. The two approaches are evaluated on the REVERB Challenge 2014 tasks. Both speech enhancement and automatic speech recognition (ASR) results show that the DNN-based mappings significantly reduce the reverberation in speech and improve both speech quality and ASR performance. For the speech enhancement task, the proposed dynamic feature constraint help to improve cepstral distance, frequency-weighted segmental signal-to-noise ratio (SNR), and log likelihood ratio metrics while moderately degrades the speech-to-reverberation modulation energy ratio. In addition, the cross transform feature adaptation improves the ASR performance significantly for clean-condition trained acoustic models.

  2. Dynamical features of reaction-diffusion fronts in fractals.

    PubMed

    Méndez, Vicenç; Campos, Daniel; Fort, Joaquim

    2004-01-01

    The speed of front propagation in fractals is studied by using (i) the reduction of the reaction-transport equation into a Hamilton-Jacobi equation and (ii) the local-equilibrium approach. Different equations proposed for describing transport in fractal media, together with logistic reaction kinetics, are considered. Finally, we analyze the main features of wave fronts resulting from this dynamic process, i.e., why they are accelerated and what is the exact form of this acceleration. PMID:14995742

  3. Dynamical Systems Analysis of Fully 3D Ocean Features

    NASA Astrophysics Data System (ADS)

    Pratt, L. J.

    2011-12-01

    Dynamical systems analysis of transport and stirring processes has been developed most thoroughly for 2D flow fields. The calculation of manifolds, turnstile lobes, transport barriers, etc. based on observations of the ocean is most often conducted near the sea surface, whereas analyses at depth, usually carried out with model output, is normally confined to constant-z surfaces. At the meoscale and larger, ocean flows are quasi 2D, but smaller scale (submesoscale) motions, including mixed layer phenomena with significant vertical velocity, may be predominantly 3D. The zoology of hyperbolic trajectories becomes richer in such cases and their attendant manifolds are much more difficult to calculate. I will describe some of the basic geometrical features and corresponding Lagrangian Coherent Features expected to arise in upper ocean fronts, eddies, and Langmuir circulations. Traditional GFD models such as the rotating can flow may capture the important generic features. The dynamical systems approach is most helpful when these features are coherent and persistent and the implications and difficulties for this requirement in fully 3D flows will also be discussed.

  4. Fast Point-Feature Label Placement for Dynamic Visualizations

    SciTech Connect

    Mote, Kevin D.

    2008-01-21

    This paper presents a brand new approach for automated feature-point label de-confliction. It outlines a method for labeling the point-features on dynamic maps in real time without a pre-processing stage. The algorithm described provides an efficient, scalable, and exceptionally fast method of labeling interactive charts and diagrams, offering interaction speeds at multiple frames per second on maps with tens of thousands of nodes. To accomplish this, the algorithm employs an efficient approach -- called the "trellis strategy" -- along with a unique label candidate cost analysis, to determine the “least expensive” label configuration. The speed and scalability of this approach makes it suitable for the complex and ever-accelerating demands of interactive visual analytic applications.

  5. Molecular Dynamics Simulations Of Nanometer-Scale Feature Etch

    SciTech Connect

    Vegh, J. J.; Graves, D. B.

    2008-09-23

    Molecular dynamics (MD) simulations have been carried out to examine fundamental etch limitations. Beams of Ar{sup +}, Ar{sup +}/F and CF{sub x}{sup +} (x = 2,3) with 2 nm diameter cylindrical confinement were utilized to mimic 'perfect' masks for small feature etching in silicon. The holes formed during etch exhibit sidewall damage and passivation as a result of ion-induced mixing. The MD results predict a minimum hole diameter of {approx}5 nm after post-etch cleaning of the sidewall.

  6. Unique Features and Spacecraft Applications of Dynamic Isotope Power Systems

    SciTech Connect

    Raab, B.

    1982-01-01

    The dynamic isotope power system represents the most recent attempt to develop a heat-engine generator for space electric power. A major objective in this most recent effort was to increase the power and to reduce the cost of nuclear space power systems to the point where the unique features of this power source could be brought to bear for Earth-orbit missions which could benefit therefrom. This objective was largely achieved; both weight and cost of the dynamic isotope systems are comparable to solar power systems. The dynamic isotope power system, designed for spacecraft requiring prime power in the 500-2000 W range, has been successfully built and ground tested. A number of studies, summarized herein, have demonstrated the advantages of using such a power system instead of the conventional solar system for a variety of Earth-orbit missions. These advantages stem from the unique nature of the dynamic isotope system, different in kind from solar power systems. As a result, in many cases, the spacecraft design can be significantly simplified and more closely harmonized with mission requirements. This overall advantage can be crucial in missions which have stringent pointing, stability, viewing, and/or positioning requirements.

  7. Application of successive test feature classifier to dynamic recognition problems

    NASA Astrophysics Data System (ADS)

    Sakata, Yukinobu; Kaneko, Shun'ichi; Tanaka, Takayuki

    2005-12-01

    A novel successive learning algorithm is proposed for efficiently handling sequentially provided training data based on Test Feature Classifier (TFC), which is non-parametric and effective even for small data. We have proposed a novel classifier TFC utilizing prime test features (PTF) which is combination feature subsets for getting excellent performance. TFC has characteristics as follows: non-parametric learning, no mis-classification of training data. And then, in some real-world problems, the effectiveness of TFC is confirmed through way applications. However, TFC has a problem that it must be reconstructed even when any sub-set of data is changed. In the successive learning, after recognition of a set of unknown objects, they are fed into the classifier in order to obtain a modified classifier. We propose an efficient algorithm for reconstruction of PTFs, which is formalized in cases of addition and deletion of training data. In the verification experiment, using the successive learning algorithm, we can save about 70% on the total computational cost in comparison with a batch learning. We applied the proposed successive TFC to dynamic recognition problems from which the characteristic of training data changes with progress of time, and examine the characteristic by the fundamental experiments. Support Vector Machine (SVM) which is well established in algorithm and on practical application, was compared with the proposed successive TFC. And successive TFC indicated high performance compared with SVM.

  8. Dynamical features of hazardous near-Earth objects

    NASA Astrophysics Data System (ADS)

    Emel'yanenko, V. V.; Naroenkov, S. A.

    2015-07-01

    We discuss the dynamical features of near-Earth objects moving in dangerous proximity to Earth. We report the computation results for the motions of all observed near-Earth objects over a 600-year-long time period: 300 years in the past and 300 years in the future. We analyze the dynamical features of Earth-approaching objects. In particular, we established that the observed distribution of geocentric velocities of dangerous objects depends on their size. No bodies with geocentric velocities smaller that 5 kms-1 have been found among hazardous objects with absolute magnitudes H <18, whereas 9% of observed objects with H <27 pass near Earth moving at such velocities. On the other hand, we found a tendency for geocentric velocities to increase at H >29. We estimated the distribution of absolute magnitudes of hazardous objects based on our analysis of the data for the asteroids that have passed close to Earth. We inferred the Earth-impact frequencies for objects of different sizes. Impacts of objects with H <18 with Earth occur on average once every 0.53 Myr, and impacts of objects with H <27—once every 130-240 years. We show that currently about 0.1% of all near-Earth objects with diameters greater than 10 m have been discovered. We point out the discrepancies between the estimates of impact rates of Chelyabinsk-type objects, determined from fireball observations and from the data of telescopic asteroid tracking surveys. These estimates can be reconciled assuming that Chelyabinsk-sized asteroids have very low albedos (about 0.02 on average).

  9. Intracellular calcium dynamics dependent on defined microtopographical features of titanium.

    PubMed

    Staehlke, Susanne; Koertge, Andreas; Nebe, Barbara

    2015-04-01

    Detailed insights into the complex cellular behavior at the biomaterial interface are crucial for the improvement of implant surfaces with respect to their acceptance and integration. The cells perceive microtopographical features and, in consequence, rearrange their adhesion structures like the actin cytoskeleton and adaptor proteins. But little is known about whether these altered cellular phenotypes have consequences for intracellular calcium signaling and its dynamics. To elucidate if an artificial, geometrical microtopography influences calcium ion (Ca(2+)) mobilization in osteoblasts, human MG-63 cells were stained with the calcium dye Fluo 3-acetoxymethyl ester and set on defined silicon-titanium (Ti) arrays with regular pillar structures (P5, 5 × 5 × 5 μm) and compared with planar Ti. To induce an immediate calcium signal, cells were stimulated with adenosine 5'-triphosphate (ATP). Interestingly, osteoblasts on micropillars expressing a shortened actin cytoskeleton were hampered in their calcium mobilization potential in signal height as well duration. Even the basal level of the intracellular Ca(2+) concentration was reduced, which was accompanied by a disturbed fibronectin synthesis. The expression of the voltage-sensitive calcium channels Cav1.2, Cav1.3 (L-type) and Cav3.1, Cav3.2, Cav3.3 (T-type) as well as the signaling proteins phospho-AKT and phospho-GSK3α/β remained unaffected on pillars. The topography-dependent calcium dynamics observed here provide new insights into how topographical cues alter cell functions - via the intracellular Ca(2+) signaling. PMID:25678115

  10. Dynamically-Tunable Smart Composites Featuring Electro-Rheological Fluids

    NASA Astrophysics Data System (ADS)

    Gandhi, Mukesh V.; Thompson, Brian S.

    1990-02-01

    A new generation of revolutionary multi-functional, dynamically-tunable, intelligent, ultra-advanced composite materials featuring electro-rheological fluids is proposed herein for the active continuum vibrational-control of structural systems. This paper reports on pioneering proof-of-concept experimental investigations focused on evaluating the elastodynamic transient and also the forced response characteristics of beams fabricated in this new class of materials. The results of these investigations clearly demonstrate the ability to dramatically change the vibrational characteristics of beam-like specimens fabricated in ultra-advanced composite materials by changing the electrical field imposed on the fluid domains. In addition, experimental results are presented which characterize the elastodynamic response of a connecting rod of a slider-crank mechanism fabricated in these ultra-advanced composite materials. Again, the combined forced and parametric responses are controlled by the voltage imposed on the electro-rheological fluid domain in the structure. The capability of these materials to interface with modern solid-state electronics can be exploited by extending the fundamental phenomenological work presented herein through the successful incorporation of intelligent sensor technologies and modern control strategies in order to significantly accelerate the evolution of these novel composite materials for the military and aerospace industries.

  11. Mutations in Twinkle primase-helicase cause Perrault syndrome with neurologic features

    PubMed Central

    Morino, Hiroyuki; Matsuda, Yukiko; Walsh, Tom; Ohsawa, Ryosuke; Newby, Marta; Hiraki-Kamon, Keiko; Kuramochi, Masahito; Lee, Ming K.; Klevit, Rachel E.; Martin, Alan; Maruyama, Hirofumi; King, Mary-Claire

    2014-01-01

    Objective: To identify the genetic cause in 2 families of progressive ataxia, axonal neuropathy, hyporeflexia, and abnormal eye movements, accompanied by progressive hearing loss and ovarian dysgenesis, with a clinical diagnosis of Perrault syndrome. Methods: Whole-exome sequencing was performed to identify causative mutations in the 2 affected sisters in each family. Family 1 is of Japanese ancestry, and family 2 is of European ancestry. Results: In family 1, affected individuals were compound heterozygous for chromosome 10 open reading frame 2 (C10orf2) p.Arg391His and p.Asn585Ser. In family 2, affected individuals were compound heterozygous for C10orf2 p.Trp441Gly and p.Val507Ile. C10orf2 encodes Twinkle, a primase-helicase essential for replication of mitochondrial DNA. Conservation and structural modeling support the causality of the mutations. Twinkle is known also to harbor multiple mutations, nearly all missenses, leading to dominant progressive external ophthalmoplegia type 3 and to recessive mitochondrial DNA depletion syndrome 7, also known as infantile-onset spinocerebellar ataxia. Conclusions: Our study identifies Twinkle mutations as a cause of Perrault syndrome accompanied by neurologic features and expands the phenotypic spectrum of recessive disease caused by mutations in Twinkle. The phenotypic heterogeneity of conditions caused by Twinkle mutations and the genetic heterogeneity of Perrault syndrome call for genomic definition of these disorders. PMID:25355836

  12. Causes, Features, and Outcomes of Drug-Induced Liver Injury in 69 Children from China

    PubMed Central

    Zhu, Yun; Li, Yong-gang; Wang, Jia-bo; Liu, Shu-hong; Wang, Li-fu; Zhao, Yan-ling; Bai, Yun-feng; Wang, Zhong-xia; Li, Jian-yu; Xiao, Xiao-he

    2015-01-01

    Background/Aims Drug-induced liver injury (DILI) is a frequent cause of pediatric liver disease; however, the data on DILI are remarkably limited. Methods All 69 children hospitalized with DILI between January 2009 and December 2011 were retrospectively studied. Results A total of 37.7% of the children had medical histories of respiratory infection. The clinical injury patterns were as follows: hepatocellular 89.9%, cholestatic 2.9%, and mixed 7.2%. Liver biopsies from 55 children most frequently demonstrated chronic (47.3%) and acute (27.3%) hepatitis. Hypersensitivity features, namely, fever (31.9%), rash (21.7%), and eosinophilia (1.4%), were found. Twenty-four children (34.8%) developed chronic DILI. Antibiotics (26.1%) were the most common Western medicines (WMs) causing DILI, and the major implicated herbs were Ephedra sinica and Polygonum multiflorum. Compared with WM, the children whose injuries were caused by Chinese herbal medicine (CHM) showed a higher level of total bilirubin (1.4 mg/dL vs 16.6 mg/dL, p=0.004) and a longer prothrombin time (11.8 seconds vs 17.3 seconds, p=0.012), but they exhibited less chronic DILI (2/15 vs 18/39, p=0.031). Conclusions Most cases of DILI in children are caused by antibiotics or CHM used to treat respiratory infection and present with hepatocellular injury. Compared with WM, CHM is more likely to cause severe liver injury, but liver injury caused by CHM is curable. PMID:25717050

  13. Dynamical features of the wake behind a pitching foil

    NASA Astrophysics Data System (ADS)

    Deng, Jian; Sun, Liping; Shao, Xueming

    2015-12-01

    As an extension of the previous study on the three-dimensional transition of the wake behind a pitching foil [Deng and Caulfield, Phys. Rev. E 91, 043017 (2015)], 10.1103/PhysRevE.91.043017, this investigation draws a comprehensive map on the pitching frequency-amplitude phase space. First, by fixing the Reynolds number at Re=1700 and varying the pitching frequency and amplitude, we identify three key dynamical features of the wake: first, the transition from Bénard-von Kármán (BvK) vortex streets to reverse BvK vortex streets, and second, the symmetry breaking of this reverse BvK wake leading to a deflected wake, and a further transition from two-dimensional (2D) wakes to three-dimensional (3D) wakes. The transition boundary between the 2D and 3D wakes lies top right of the wake deflection boundary, implying a correlation between the wake deflection and the 2D to 3D wake transition, confirming that this transition occurs after the wake deflection. This paper supports the previous extensive numerical studies under two-dimensional assumption at low Reynolds number, since it is indeed two dimensional except for the cases at very high pitching frequencies or large amplitudes. Furthermore, by three-dimensional direct numerical simulations (DNSs), we confirm the previous statement about the physical realizability of the short wavelength mode at β =30 (or λz=0.21 ) for Re=1500 . By comparing the three-dimensional vortical structures by DNSs with that from the reconstruction of Floquet modes, we find a good consistency between them, both exhibiting clear streamwise structures in the wake.

  14. Electrophysiologic features of SYT2 mutations causing a treatable neuromuscular syndrome

    PubMed Central

    Herrmann, David N.; Bansagi, Boglarka; Hasan, Bashar Awwad Shiekh; Lofra, Robert Muni; Logigian, Eric L.; Sowden, Janet E.; Almodovar, Jorge L.; Littleton, J. Troy; Zuchner, Stephan; Horvath, Rita; Lochmüller, Hanns

    2015-01-01

    Objectives: To describe the clinical and electrophysiologic features of synaptotagmin II (SYT2) mutations, a novel neuromuscular syndrome characterized by foot deformities and fatigable ocular and lower limb weakness, and the response to modulators of acetylcholine release. Methods: We performed detailed clinical and neurophysiologic assessment in 2 multigenerational families with dominant SYT2 mutations (c.920T>G [p.Asp307Ala] and c.923G>A [p.Pro308Leu]). Serial clinical and electrophysiologic assessments were performed in members of one family treated first with pyridostigmine and then with 3,4-diaminopyridine. Results: Electrophysiologic testing revealed features indicative of a presynaptic deficit in neurotransmitter release with posttetanic potentiation lasting up to 60 minutes. Treatment with 3,4-diaminopyridine produced both a clinical benefit and an improvement in neuromuscular transmission. Conclusion: SYT2 mutations cause a novel and potentially treatable complex presynaptic congenital myasthenic syndrome characterized by motor neuropathy causing lower limb wasting and foot deformities, with reflex potentiation following exercise and a uniquely prolonged period of posttetanic potentiation. PMID:26519543

  15. Vascular Dynamics Aid a Coupled Neurovascular Network Learn Sparse Independent Features: A Computational Model

    PubMed Central

    Philips, Ryan T.; Chhabria, Karishma; Chakravarthy, V. Srinivasa

    2016-01-01

    Cerebral vascular dynamics are generally thought to be controlled by neural activity in a unidirectional fashion. However, both computational modeling and experimental evidence point to the feedback effects of vascular dynamics on neural activity. Vascular feedback in the form of glucose and oxygen controls neuronal ATP, either directly or via the agency of astrocytes, which in turn modulates neural firing. Recently, a detailed model of the neuron-astrocyte-vessel system has shown how vasomotion can modulate neural firing. Similarly, arguing from known cerebrovascular physiology, an approach known as “hemoneural hypothesis” postulates functional modulation of neural activity by vascular feedback. To instantiate this perspective, we present a computational model in which a network of “vascular units” supplies energy to a neural network. The complex dynamics of the vascular network, modeled by a network of oscillators, turns neurons ON and OFF randomly. The informational consequence of such dynamics is explored in the context of an auto-encoder network. In the proposed model, each vascular unit supplies energy to a subset of hidden neurons of an autoencoder network, which constitutes its “projective field.” Neurons that receive adequate energy in a given trial have reduced threshold, and thus are prone to fire. Dynamics of the vascular network are governed by changes in the reconstruction error of the auto-encoder network, interpreted as the neuronal demand. Vascular feedback causes random inactivation of a subset of hidden neurons in every trial. We observe that, under conditions of desynchronized vascular dynamics, the output reconstruction error is low and the feature vectors learnt are sparse and independent. Our earlier modeling study highlighted the link between desynchronized vascular dynamics and efficient energy delivery in skeletal muscle. We now show that desynchronized vascular dynamics leads to efficient training in an auto-encoder neural

  16. Vascular Dynamics Aid a Coupled Neurovascular Network Learn Sparse Independent Features: A Computational Model.

    PubMed

    Philips, Ryan T; Chhabria, Karishma; Chakravarthy, V Srinivasa

    2016-01-01

    Cerebral vascular dynamics are generally thought to be controlled by neural activity in a unidirectional fashion. However, both computational modeling and experimental evidence point to the feedback effects of vascular dynamics on neural activity. Vascular feedback in the form of glucose and oxygen controls neuronal ATP, either directly or via the agency of astrocytes, which in turn modulates neural firing. Recently, a detailed model of the neuron-astrocyte-vessel system has shown how vasomotion can modulate neural firing. Similarly, arguing from known cerebrovascular physiology, an approach known as "hemoneural hypothesis" postulates functional modulation of neural activity by vascular feedback. To instantiate this perspective, we present a computational model in which a network of "vascular units" supplies energy to a neural network. The complex dynamics of the vascular network, modeled by a network of oscillators, turns neurons ON and OFF randomly. The informational consequence of such dynamics is explored in the context of an auto-encoder network. In the proposed model, each vascular unit supplies energy to a subset of hidden neurons of an autoencoder network, which constitutes its "projective field." Neurons that receive adequate energy in a given trial have reduced threshold, and thus are prone to fire. Dynamics of the vascular network are governed by changes in the reconstruction error of the auto-encoder network, interpreted as the neuronal demand. Vascular feedback causes random inactivation of a subset of hidden neurons in every trial. We observe that, under conditions of desynchronized vascular dynamics, the output reconstruction error is low and the feature vectors learnt are sparse and independent. Our earlier modeling study highlighted the link between desynchronized vascular dynamics and efficient energy delivery in skeletal muscle. We now show that desynchronized vascular dynamics leads to efficient training in an auto-encoder neural network. PMID

  17. Glycine decarboxylase deficiency causes neural tube defects and features of non-ketotic hyperglycinemia in mice

    PubMed Central

    Pai, Yun Jin; Leung, Kit-Yi; Savery, Dawn; Hutchin, Tim; Prunty, Helen; Heales, Simon; Brosnan, Margaret E.; Brosnan, John T.; Copp, Andrew J.; Greene, Nicholas D.E.

    2015-01-01

    Glycine decarboxylase (GLDC) acts in the glycine cleavage system to decarboxylate glycine and transfer a one-carbon unit into folate one-carbon metabolism. GLDC mutations cause a rare recessive disease non-ketotic hyperglycinemia (NKH). Mutations have also been identified in patients with neural tube defects (NTDs); however, the relationship between NKH and NTDs is unclear. We show that reduced expression of Gldc in mice suppresses glycine cleavage system activity and causes two distinct disease phenotypes. Mutant embryos develop partially penetrant NTDs while surviving mice exhibit post-natal features of NKH including glycine accumulation, early lethality and hydrocephalus. In addition to elevated glycine, Gldc disruption also results in abnormal tissue folate profiles, with depletion of one-carbon-carrying folates, as well as growth retardation and reduced cellular proliferation. Formate treatment normalizes the folate profile, restores embryonic growth and prevents NTDs, suggesting that Gldc deficiency causes NTDs through limiting supply of one-carbon units from mitochondrial folate metabolism. PMID:25736695

  18. Detection of dynamic background due to swaying movements from motion features.

    PubMed

    Pham, Duc-Son; Arandjelović, Ognjen; Venkatesh, Svetha

    2015-01-01

    Dynamically changing background (dynamic background) still presents a great challenge to many motion-based video surveillance systems. In the context of event detection, it is a major source of false alarms. There is a strong need from the security industry either to detect and suppress these false alarms, or dampen the effects of background changes, so as to increase the sensitivity to meaningful events of interest. In this paper, we restrict our focus to one of the most common causes of dynamic background changes: 1) that of swaying tree branches and 2) their shadows under windy conditions. Considering the ultimate goal in a video analytics pipeline, we formulate a new dynamic background detection problem as a signal processing alternative to the previously described but unreliable computer vision-based approaches. Within this new framework, we directly reduce the number of false alarms by testing if the detected events are due to characteristic background motions. In addition, we introduce a new data set suitable for the evaluation of dynamic background detection. It consists of real-world events detected by a commercial surveillance system from two static surveillance cameras. The research question we address is whether dynamic background can be detected reliably and efficiently using simple motion features and in the presence of similar but meaningful events, such as loitering. Inspired by the tree aerodynamics theory, we propose a novel method named local variation persistence (LVP), that captures the key characteristics of swaying motions. The method is posed as a convex optimization problem, whose variable is the local variation. We derive a computationally efficient algorithm for solving the optimization problem, the solution of which is then used to form a powerful detection statistic. On our newly collected data set, we demonstrate that the proposed LVP achieves excellent detection results and outperforms the best alternative adapted from existing art in

  19. Hepatic Sinusoidal Obstruction Syndrome Caused by Herbal Medicine: CT and MRI Features

    PubMed Central

    Zhou, Hua; Wang, Yi-Xiang J.; Lou, Hai-yan; Xu, Xiao-jun

    2014-01-01

    Objective To describe the CT and MRI features of hepatic sinusoidal obstruction syndrome (HSOS) caused by herbal medicine Gynura segetum. Materials and Methods The CT and MRI features of 16 consecutive Gynura segetum induced HSOS cases (12 men, 4 women) were analyzed. Eight patients had CT; three patients had MRI, and the remaining five patients had both CT and MRI examinations. Based on their clinical presentations and outcomes, the patients were classified into three categories: mild, moderate, and severe. The severity of the disease was also evaluated radiologically based on the abnormal hepatic patchy enhancement in post-contrast CT or MRI images. Results Ascites, patchy liver enhancement, and main right hepatic vein narrowing or occlusion were present in all 16 cases. Hepatomegaly and gallbladder wall thickening were present in 14 cases (87.5%, 14/16). Periportal high intensity on T2-weighted images was present in 6 cases (75%, 6/8). Normal liver parenchymal enhancement surrounding the main hepatic vein forming a clover-like sign was observed in 4 cases (25%, 4/16). The extent of patchy liver enhancement was statistically associated with clinical severity classification (kappa = 0.565). Conclusion Ascites, patchy liver enhancement, and the main hepatic veins narrowing were the most frequent signs of herbal medicine induced HSOS. The grade of abnormal patchy liver enhancement was associated with the clinical severity. PMID:24643319

  20. Endophthalmitis Caused by Enterococcus faecalis: Clinical Features, Antibiotic Sensitivities, and Outcomes

    PubMed Central

    Kuriyan, Ajay E.; Sridhar, Jayanth; Flynn, Harry W.; Smiddy, William E.; Albini, Thomas A.; Berrocal, Audina M.; Forster, Richard K.; Belin, Peter J.; Miller, Darlene

    2014-01-01

    Purpose To report the clinical features, antibiotic sensitivities, and visual acuity (VA) outcomes of endophthalmitis caused by Enterococcus faecalis. Study Design Retrospective, observational case series. Methods A consecutive case series of patients with culture-positive endophthalmitis caused by E. faecalis between January 1, 2002 and December 31, 2012 at an academic referral center. Results Of 14 patients identified, clinical settings included bleb-associated (n=8), post-cataract surgery (n=4), and post-penetrating keratoplasty (n=2). All isolates were vancomycin sensitive. When comparing isolates in the current study to isolates from 1990–2001, the minimal inhibitory concentration required to inhibit 90% of isolates (MIC 90, μg/ml) increased for ciprofloxacin (4 from 1), erythromycin (256 from 4), and penicillin (8 from 4), indicating higher levels of resistance. The MIC 90 remained the same for vancomycin (2) and linezolid (2). Presenting VA ranged from hand motion to no light perception. Initial treatment strategies were vitreous tap and intravitreal antibiotic injection (n=12) and pars plana vitrectomy with intravitreal antibiotic injection (n=2). VA outcomes were ≤ 20/400 in 13 (93%) of 14 patients. Conclusions Although all isolates were sensitive to vancomycin and linezolid, higher MIC 90s for isolates in the current study, compared to isolates from 1990 to 2001, occurred with ciprofloxacin, erythromycin, and penicillin. Despite prompt treatment, most patients had poor outcomes. PMID:25089354

  1. Cause of long thoracic nerve palsy: a possible dynamic fascial sling cause.

    PubMed

    Hester, P; Caborn, D N; Nyland, J

    2000-01-01

    Long thoracic nerve palsy can result from sudden or repetitive external biomechanical forces. This investigation describes a possible dynamic cause from internal forces. Six fresh cadaveric shoulders (3 female, 3 male, 4 left, 2 right) with full range of motion were systematically dissected to evaluate the anatomic course of the long thoracic nerve. In all specimens a tight fascial band of tissue arose from the inferior aspect of the brachial plexus, extended just superior to the middle scalene muscle insertion on the first rib, and presented a digitation that extended to the proximal aspect of the serratus anterior muscle. With progressive manual abduction and external rotation, the long thoracic nerve was found to "bow-string" across the fascial band. Medial and upward migration of the superior most aspect of the scapula was found to further compress the long thoracic nerve. Previous investigations have reported that nerves tolerate a 10% increase in their resting length before a stretch-induced neuropraxia develops. Previous studies postulated that long thoracic nerve palsy resulted from the tethering effect of the scalenus medius muscle as it actively or passively compressed the nerve; however, similar neuromuscular relationships occur in many other anatomic sites without ill effect. We propose that the cause of long thoracic nerve palsy may be this "bow-stringing" phenomenon of the nerve across this tight fascial band. This condition may be further exacerbated with medial and upward migration of the superior aspect of the scapula as is commonly seen with scapulothoracic dyskinesia and fatigue of the scapular stabilizers. Rehabilitation for long thoracic nerve palsy may therefore benefit from special attention to scapulothoracic muscle stabilization. PMID:10717860

  2. Causal information quantification of prominent dynamical features of biological neurons.

    PubMed

    Montani, Fernando; Baravalle, Roman; Montangie, Lisandro; Rosso, Osvaldo A

    2015-12-13

    Neurons tend to fire a spike when they are near a bifurcation from the resting state to spiking activity. It is a delicate balance between noise, dynamic currents and initial condition that determines the phase diagram of neural activity. Many possible ionic mechanisms can be accounted for as the source of spike generation. Moreover, the biophysics and the dynamics behind it can usually be described through a phase diagram that involves membrane voltage versus the activation variable of the ionic channel. In this paper, we present a novel methodology to characterize the dynamics of this system, which takes into account the fine temporal 'structures' of the complex neuronal signals. This allows us to accurately distinguish the most fundamental properties of neurophysiological neurons that were previously described by Izhikevich considering the phase-space trajectory, using a time causal space: statistical complexity versus Fisher information versus Shannon entropy. PMID:26527819

  3. Neurocognitive Features Distinguishing Primary Central Nervous System Lymphoma from Other Possible Causes of Rapidly Progressive Dementia

    PubMed Central

    Deutsch, Mariel B.; Mendez, Mario F.

    2015-01-01

    Objective Define the neurocognitive features of primary central nervous system lymphoma (PCNSL) presenting with dementia, and compare with other causes of rapidly progressive dementia (RPD). Background PCNSL can present as an RPD. Differentiating PCNSL from other RPDs is critical because lymphomatous dementia may be reversible, and untreated PCNSL is fatal. Methods We performed a meta-analysis of case reports of dementia from PCNSL (between 1950 and 2013); 20 patients (14 with lymphomatosis cerebri) met our criteria. We compared these patients to a case series of patients with RPD from Creutzfeldt-Jakob disease and other non-PCNSL etiologies (Sala et al, 2012. Alzheimer Dis Assoc Disord. 26:267–271). Results Median age was 66 (range 41–81); 70% were men. Time from symptom onset to evaluation was < 6 months in 65%. No patients had seizures; 5% had headaches; 45% had non-aphasic speech difficulty. There was significantly more memory impairment in patients with PCNSL than other RPDs and significantly less myoclonus and parkinsonism. Behavioral changes and cerebellar signs were not significantly different. Significantly more patients with PCNSL than other RPDs had white matter changes; significantly fewer had atrophy. Elevated CSF protein and pleocytosis were more frequent in PCNSL; patients with other RPDs tended to have normal CSF ± 14-3-3 protein. Conclusions Unlike patients with RPD from other causes, those with PCNSL commonly present with impaired memory, apathy, and abnormal speech and gait, without headache, seizure, or myoclonus. White-matter changes and CSF abnormalities predominate. Improved clinical awareness of PCNSL can prompt earlier diagnosis and treatment. PMID:25812125

  4. Analysis of motion features for molecular dynamics simulation of proteins

    NASA Astrophysics Data System (ADS)

    Kamada, Mayumi; Toda, Mikito; Sekijima, Masakazu; Takata, Masami; Joe, Kazuki

    2011-01-01

    Recently, a new method for time series analysis using the wavelet transformation has been proposed by Sakurai et al. We apply it to molecular dynamics simulation of Thermomyces lanuginosa lipase (TLL). Introducing indexes to characterize collective motion of the protein, we have obtained the following two results. First, time evolution of the collective motion involves not only the dynamics within a single potential well but also takes place wandering around multiple conformations. Second, correlation of the collective motion between secondary structures shows that collective motion exists involving multiple secondary structures. We discuss future prospects of our study involving 'disordered proteins'.

  5. Correlated random walks caused by dynamical wavefunction collapse.

    PubMed

    Bedingham, D J; Ulbricht, H

    2015-01-01

    Wavefunction collapse models modify Schrödinger's equation so that it describes the collapse of a superposition of macroscopically distinguishable states as a dynamical process. This provides a basis for the resolution of the quantum measurement problem. An additional generic consequence of the collapse mechanism is that it causes particles to exhibit a tiny random diffusive motion. Here it is shown that for the continuous spontaneous localization (CSL) model—one of the most well developed collapse models—the diffusions of two sufficiently nearby particles are positively correlated. An experimental test of this effect is proposed in which random displacements of pairs of free nanoparticles are measured after they have been simultaneously released from nearby traps. The experiment must be carried out at sufficiently low temperature and pressure in order for the collapse effects to dominate over the ambient environmental noise. It is argued that these constraints can be satisfied by current technologies for a large region of the viable parameter space of the CSL model. The effect disappears as the separation between particles exceeds the CSL length scale. The test therefore provides a means of bounding this length scale. PMID:26303388

  6. Correlated random walks caused by dynamical wavefunction collapse

    NASA Astrophysics Data System (ADS)

    Bedingham, D. J.; Ulbricht, H.

    2015-08-01

    Wavefunction collapse models modify Schrödinger’s equation so that it describes the collapse of a superposition of macroscopically distinguishable states as a dynamical process. This provides a basis for the resolution of the quantum measurement problem. An additional generic consequence of the collapse mechanism is that it causes particles to exhibit a tiny random diffusive motion. Here it is shown that for the continuous spontaneous localization (CSL) model—one of the most well developed collapse models—the diffusions of two sufficiently nearby particles are positively correlated. An experimental test of this effect is proposed in which random displacements of pairs of free nanoparticles are measured after they have been simultaneously released from nearby traps. The experiment must be carried out at sufficiently low temperature and pressure in order for the collapse effects to dominate over the ambient environmental noise. It is argued that these constraints can be satisfied by current technologies for a large region of the viable parameter space of the CSL model. The effect disappears as the separation between particles exceeds the CSL length scale. The test therefore provides a means of bounding this length scale.

  7. Clinical and radiological features of brain neurotoxicity caused by antitumor and immunosuppressant treatments.

    PubMed

    Erbetta, Alessandra; Salmaggi, Andrea; Sghirlanzoni, Angelo; Silvani, Antonio; Potepan, Paolo; Botturi, Andrea; Ciceri, Elisa; Bruzzone, Maria Grazia

    2008-06-01

    Antitumor and immunosuppressant treatment-related neurotoxicity can determine nonspecific clinical syndromes. Exclusion of other possible causes, among which tumor progression, appearance of paraneoplastic disease, renal or hepatic failure, diabetes or hypertension, is relevant. We report clinical and neuroradiological features in five patients with neurotoxic syndromes due to chemotherapy/radiotherapy or immunosuppression in the context of neoplastic disease/organ transplantation. Acute neurological syndrome developed in three patients after methotrexate (MTX), cyclosporine A, and L-asparaginase therapy, respectively. MRI showed posterior reversible encephalopathy in two cases and venous thrombosis with intraparenchymal hematoma in the third patient. Late onset clinical syndrome occurred in the last two patients, treated with MTX or radiation therapy for breast cancer metastasis and pituitary adenoma. Neuroimaging showed brain diffuse abnormalities. Patients affected by tumors suffer from increased risk for treatment-related toxicities. Appearance or worsening of neurological signs and symptoms challenge the clinician to discriminate between CNS involvement by the tumor, toxicity of drugs, parane-oplastic disease and infections. MRI has a key role in differential diagnosis. Close interaction between the neurologist, the oncologist and the neuroradiologist leads to the optimal management of patients. PMID:18612759

  8. From the nephrologist's point of view: diversity of causes and clinical features of acute kidney injury

    PubMed Central

    Bienholz, Anja; Wilde, Benjamin; Kribben, Andreas

    2015-01-01

    Acute kidney injury (AKI) is a clinical syndrome with multiple entities. Although AKI implies renal damage, functional impairment or both, diagnosis is solely based on the functional parameters of serum creatinine and urine output. The latest definition was provided by the Kidney Disease Improving Global Outcomes (KDIGO) working group in 2012. Independent of the underlying disease, and even in the case of full recovery, AKI is associated with an increased morbidity and mortality. Awareness of the patient's individual risk profile and the diversity of causes and clinical features of AKI is pivotal for optimization of prophylaxes, diagnosis and therapy of each form of AKI. A differentiated and individualized approach is required to improve patient mortality, morbidity, long-term kidney function and eventually the quality of life. In this review, we provide an overview of the different clinical settings in which specific forms of AKI may occur and point out possible diagnostic as well as therapeutic approaches. Secifically AKI is discussed in the context of non-kidney organ failure, organ transplantation, sepsis, malignancy and autoimmune disease. PMID:26251707

  9. Dominant mutations in KAT6A cause intellectual disability with recognizable syndromic features.

    PubMed

    Tham, Emma; Lindstrand, Anna; Santani, Avni; Malmgren, Helena; Nesbitt, Addie; Dubbs, Holly A; Zackai, Elaine H; Parker, Michael J; Millan, Francisca; Rosenbaum, Kenneth; Wilson, Golder N; Nordgren, Ann

    2015-03-01

    Through a multi-center collaboration study, we here report six individuals from five unrelated families, with mutations in KAT6A/MOZ detected by whole-exome sequencing. All five different de novo heterozygous truncating mutations were located in the C-terminal transactivation domain of KAT6A: NM_001099412.1: c.3116_3117 delCT, p.(Ser1039∗); c.3830_3831insTT, p.(Arg1278Serfs∗17); c.3879 dupA, p.(Glu1294Argfs∗19); c.4108G>T p.(Glu1370∗) and c.4292 dupT, p.(Leu1431Phefs∗8). An additional subject with a 0.23 MB microdeletion including the entire KAT6A reading frame was identified with genome-wide array comparative genomic hybridization. Finally, by detailed clinical characterization we provide evidence that heterozygous mutations in KAT6A cause a distinct intellectual disability syndrome. The common phenotype includes hypotonia, intellectual disability, early feeding and oromotor difficulties, microcephaly and/or craniosynostosis, and cardiac defects in combination with subtle facial features such as bitemporal narrowing, broad nasal tip, thin upper lip, posteriorly rotated or low-set ears, and microretrognathia. The identification of human subjects complements previous work from mice and zebrafish where knockouts of Kat6a/kat6a lead to developmental defects. PMID:25728777

  10. Slow dynamics in features of synchronized neural network responses

    PubMed Central

    Haroush, Netta; Marom, Shimon

    2015-01-01

    In this report trial-to-trial variations in the synchronized responses of neural networks are explored over time scales of minutes, in ex-vivo large scale cortical networks. We show that sub-second measures of the individual synchronous response, namely—its latency and decay duration, are related to minutes-scale network response dynamics. Network responsiveness is reflected as residency in, or shifting amongst, areas of the latency-decay plane. The different sensitivities of latency and decay durations to synaptic blockers imply that these two measures reflect aspects of inhibitory and excitatory activities. Taken together, the data suggest that trial-to-trial variations in the synchronized responses of neural networks might be related to effective excitation-inhibition ratio being a dynamic variable over time scales of minutes. PMID:25926787

  11. Mutations in LRP5 cause primary osteoporosis without features of OI by reducing Wnt signaling activity

    PubMed Central

    2012-01-01

    Background Primary osteoporosis is a rare childhood-onset skeletal condition whose pathogenesis has been largely unknown. We have previously shown that primary osteoporosis can be caused by heterozygous missense mutations in the Low-density lipoprotein receptor-related protein 5 (LRP5) gene, and the role of LRP5 is further investigated here. Methods LRP5 was analyzed in 18 otherwise healthy children and adolescents who had evidence of osteoporosis (manifested as reduced bone mineral density i.e. BMD, recurrent peripheral fractures and/or vertebral compression fractures) but who lacked the clinical features of osteogenesis imperfecta (OI) or other known syndromes linked to low BMD. Also 51 controls were analyzed. Methods used in the genetic analyses included direct sequencing and multiplex ligation-dependent probe amplification (MLPA). In vitro studies were performed using luciferase assay and quantitative real-time polymerase chain reaction (qPCR) to examine the effect of two novel and three previously identified mutations on the activity of canonical Wnt signaling and on expression of tryptophan hydroxylase 1 (Tph1) and 5-hydroxytryptamine (5-Htr1b). Results Two novel LRP5 mutations (c.3446 T > A; p.L1149Q and c.3553 G > A; p.G1185R) were identified in two patients and their affected family members. In vitro analyses showed that one of these novel mutations together with two previously reported mutations (p.C913fs, p.R1036Q) significantly reduced the activity of the canonical Wnt signaling pathway. Such reductions may lead to decreased bone formation, and could explain the bone phenotype. Gut-derived Lrp5 has been shown to regulate serotonin synthesis by controlling the production of serotonin rate-limiting enzyme, Tph1. LRP5 mutations did not affect Tph1 expression, and only one mutant (p.L1149Q) reduced expression of serotonin receptor 5-Htr1b (p < 0.002). Conclusions Our results provide additional information on the role of LRP5 mutations and their effects on

  12. Static and Dynamic Features for Improved HMM based Visual Speech Recognition

    NASA Astrophysics Data System (ADS)

    Rajavel, R.; Sathidevi, P. S.

    Visual speech recognition refers to the identification of utterances through the movements of lips, tongue, teeth, and other facial muscles of the speaker without using the acoustic signal. This work shows the relative benefits of both static and dynamic visual speech features for improved visual speech recognition. Two approaches for visual feature extraction have been considered: (1) an image transform based static feature approach in which Discrete Cosine Transform (DCT) is applied to each video frame and 6×6 triangle region coefficients are considered as features. Principal Component Analysis (PCA) is applied over all 60 features corresponding to the video frame to reduce the redundancy; the resultant 21 coefficients are taken as the static visual features. (2) Motion segmentation based dynamic feature approach in which the facial movements are segmented from the video file using motion history images (MHI). DCT is applied to the MHI and triangle region coefficients are taken as the dynamic visual features. Two types of experiments were done one with concatenated features and another with dimension reduced feature by using PCA to identify the utterances. The left-right continuous HMMs are used as visual speech classifier to classify nine MPEG-4 standard viseme consonants. The experimental result shows that the concatenated as well as dimension reduced features improve te visual speech recognition with a high accuracy of 92.45% and 92.15% respectively.

  13. Portal vein involvement in hepatocellular carcinoma: dynamic CT features

    SciTech Connect

    Mathieu, D.; Grenier, P.; Larde, D.; Vasile, N.

    1984-07-01

    The authors conducted a retrospective examination of 62 hepatocellular carcinomas, taking dynamic CT scans of selected sections after an intravenous contrast bolus. The proximal portal vein was involved in 40% of cases and distal segment in 16%. Angiographic correlation was available in 23 patients. The characteristic appearance of tumor within the portal vein was noted in many cases; in others, distinction between tumor and bland thrombus could not be made. Peripheral portal vein obstruction was suggested when a small, hypervascular tumor became hypodense during the portal phase of CT. The frequency and significance of these CT signs of portal vein involvement are discussed.

  14. Qualitative and quantitative features of Rayleigh-Taylor mixing dynamics

    NASA Astrophysics Data System (ADS)

    Bhowmick, Aklant; Abarzhi, Snezhana; Ramaprabhu, Praveen; Karkhanis, Varad; Lawrie, Andrew; RTI Collaboration

    2015-11-01

    We consider dynamics of Rayleigh-Taylor (RT) flow in a large aspect ratio three-dimensional domain with square symmetry in the plane for fluids with contrasting densities. In order to quantify the interface evolution from a small amplitude single-mode initial perturbation to advanced stage of RT mixing, we apply numerical simulations using the MOBILE code, theoretical analyses, including group theory and momentum model, as well as parameters describing the interplay between acceleration and turbulence. We find: In RT flow, the fluid motion is intense near the interface and is negligible far from the interface. At late times the growth rates of RT bubbles and spikes may increase without a corresponding increase of length-scales in the direction normal to acceleration. The parameters describing the interplay between acceleration and turbulence in RT mixing are shown to scale well with the flow Reynolds number and Froude number.

  15. The White Sea dynamics features derived by observations and modelling.

    NASA Astrophysics Data System (ADS)

    Semenov, E.; Yakovlev, N.

    2009-04-01

    The results of the many years of observational and modelling activity for White Sea investigation are presented. White Sea is a relatively shallow inlet of Barents Sea with the mean depth about 67m. There is a shallow (20-40m) and narrow (30-40km) passage (so called the Gorlo - "The Neck") between White and Barents Seas. Nevertheless White Sea is characterized as the area with high density of kinetic and available potential energies, which often several times exceed analogues estimates for other seas and for typical ocean conditions. It is due to strong tides, with tide heights up to 6-8m in the Gorlo and the Mezen Bay. There is also a large river run-off, with the annual discharge up to 4% of the total sea volume, and the transport of relatively salt and cold (in summer) Barents Sea waters. The combination of these factors makes the White Sea the unique object, a place where a wide range of phenomena takes place in a rather limited area. The Gorlo plays the principal role in the White Sea dynamics, acting as a kind of a hydro-dynamical filter for the incident Kelvin tidal wave. So, tide spreads as pure gravitational waves, thus the water exchange of the Central part of the sea (the Basin) with the Barents Sea improves significantly. The group velocity of the tidal wave, traveling from the Gorlo towards the Basin, drops as the horizontal scale changes and the Coriolis force becomes more important. This effect leads to the formation of the hydrological front. The tidal wave, entering the Basin, radiates inertial-gravity waves and Kelvin wave, which appeared to be the main modes of the velocity variability. It was shown, that these modes might be purely gravitational (in the area of the Solovetskiye Islands) or almost inertial (in some areas of the Basin), depending on the characteristic horizontal scales of the location. A set of numerical experiments with the original model by E. Semenov and M. Luneva were carried out to estimate the role of various physical

  16. The Effect of Dynamic Acoustical Features on Musical Timbre

    NASA Astrophysics Data System (ADS)

    Hajda, John M.

    Timbre has been an important concept for scientific exploration of music at least since the time of Helmholtz ([1877] 1954). Since Helmholtz's time, a number of studies have defined and investigated acoustical features of musical instrument tones to determine their perceptual importance, or salience (e.g., Grey, 1975, 1977; Kendall, 1986; Kendall et al., 1999; Luce and Clark, 1965; McAdams et al., 1995, 1999; Saldanha and Corso, 1964; Wedin and Goude, 1972). Most of these studies have considered only nonpercussive, or continuant, tones of Western orchestral instruments (or emulations thereof). In the past few years, advances in computing power and programming have made possible and affordable the definition and control of new acoustical variables. This chapter gives an overview of past and current research, with a special emphasis on the time-variant aspects of musical timbre. According to common observation, "music is made of tones in time" (Spaeth, 1933). We will also consider the fact that music is made of "time in tones."

  17. A Seasonal Feature in Mercury's Exosphere Caused by Meteoroids from Comet Encke

    NASA Astrophysics Data System (ADS)

    Burger, M. H.; Christou, A.; Killen, R. M.

    2015-12-01

    The planet Mercury is enveloped in a tenuous atmosphere, the result of a delicate balance between poorly understood sources and sinks (Killen et al, 2007). Meteoroid impacts are a contributing source process (eg Wurz et al, 2010), but their importance compared to other production mechanisms is uncertain. Killen and Hahn (2015) found that seasonal variations in Mercury's calcium exosphere as observed by the MASCS spectrometer onboard the MESSENGER spacecraft (Burger et al, 2014) may be due to impact vaporization of surface material by the infall of interplanetary dust. However, an additional dust source was required to explain a Ca excess at a True Anomaly Angle (TAA) of 25±5 deg. Killen and Hahn suggested that dust from comet 2P/Encke, crossing Mercury's orbital plane at TAA=45 deg, may be the culprit. We have simulated numerically the stream of meteoroids ejected from Encke to test the Killen and Hahn conjecture. We find that Encke particles evolving solely under the gravity of the major planets and the Sun encounter Mercury at TAA=50-60 deg, well after the peak of the Ca excess emission. However, the addition of Poynting-Robertson (P-R) drag in our model couples the age and size of the meteoroids to the TAA at encounter, causing smaller, older particles to encounter Mercury progressively earlier in the Hermean year. In particular, mm-sized grains ejected between 10 and 20 kyr ago impact on the nightside hemisphere of Mercury at TAA = 350-30 deg, near the observed peak time of the exospheric feature. During this presentation, we will describe our model results and discuss their implications for the physical mechanism that injects impact-liberated Ca into sunlight as well as the origin and evolution of the Encke stream of meteoroids. Astronomical research at the Armagh Observatory is funded by the Northern Ireland Department of Culture, Arts and Leisure (DCAL). RMK was supported by NASA Grant NNX07AR78G-S01 as a Participating Scientist on the NASA MESSENGER

  18. A seasonal feature in Mercury’s exosphere caused by meteoroids from comet Encke

    NASA Astrophysics Data System (ADS)

    Christou, Apostolos; Killen, Rosemary M.; Burger, Matthew H.

    2015-11-01

    The planet Mercury is enveloped in a tenuous atmosphere, the result of a delicate balance between poorly understood sources and sinks (Killen et al, 2007). Meteoroid impacts are a contributing source process (eg Wurz et al, 2010), but their importance compared to other production mechanisms is uncertain.Killen and Hahn (2015) found that seasonal variations in Mercury's calcium exosphere as observed by Mercury Atmospheric, and Surface Composition Spectrometer (MASCS) onboard the MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft (Burger et al, 2014) may be attributed to impact vaporization of surface material by the infall of interplanetary dust. However, an additional dust source was required to explain a Ca excess at a True Anomaly Angle (TAA) of 25±5 deg. Killen and Hahn suggested that dust from comet 2P/Encke, crossing Mercury's orbital plane at TAA=45 deg, may be the culprit.We have simulated numerically the stream of meteoroids ejected from Encke in order to identify those particles that impact Mercury at the present epoch and test the Killen and Hahn conjecture. We find that Encke particles evolving solely under the gravity of the major planets and the Sun encounter Mercury at TAA=50-60 deg, well after the peak of the Ca excess emission. This result is independent of the time of ejection. However, the addition of Poynting-Robertson (P-R) drag in our model couples the age and size of the meteoroids to the TAA at encounter, causing smaller, older particles to encounter Mercury progressively earlier in the Hermean year. In particular, mm-sized grains ejected between 10 and 20 kyr ago impact on the nightside hemisphere of Mercury at TAA = 350-30 deg, near the observed peak time of the exospheric feature.During this presentation, we will describe our model results and discuss their implications for the physical mechanism that injects impact-liberated Ca into sunlight as well as the origin and evolution of the Encke stream of

  19. Dynamic features of gene expression control by small regulatory RNAs.

    PubMed

    Mitarai, Namiko; Benjamin, Julie-Anna M; Krishna, Sandeep; Semsey, Szabolcs; Csiszovszki, Zsolt; Massé, Eric; Sneppen, Kim

    2009-06-30

    Small regulatory RNAs (sRNAs) in eukaryotes and bacteria play an important role in the regulation of gene expression either by binding to regulatory proteins or directly to target mRNAs. Two of the best-characterized bacterial sRNAs, Spot42 and RyhB, form a complementary pair with the ribosome binding region of their target mRNAs, thereby inhibiting translation or promoting mRNA degradation. To investigate the steady-state and dynamic potential of such sRNAs, we examine the 2 key parameters characterizing sRNA regulation: the capacity to overexpress the sRNA relative to its target mRNA and the speed at which the target mRNA is irreversibly inactivated. We demonstrate different methods to determine these 2 key parameters, for Spot42 and RyhB, which combine biochemical and genetic experiments with computational analysis. We have developed a mathematical model that describes the functional properties of sRNAs with various characteristic parameters. We observed that Spot42 and RyhB function in distinctive parameter regimes, which result in divergent mechanisms. PMID:19541626

  20. Static and dynamic features of Fourier transform profilometry: A review

    NASA Astrophysics Data System (ADS)

    Zappa, Emanuele; Busca, Giorgio

    2012-08-01

    Fringe projection techniques are very popular among the several profilometry methods proposed in literature. One of their main advantages is that most of them require one image of the object to retrieve its surface. From a theoretical point of view these techniques are based on a simple mathematical model which is at the base of the conversion of the measured quantity (usually the phase map of the image of the grid projected onto an object surface) into the height distribution of the object. However, the practical implementation of the system is not an easy task to be achieved. The mathematical models are often a simplification of the reality and it is valid only under some conditions. These discrepancies between the theory and the practice deal to a series of discussions about the quality of the measure of fringe projection techniques. This paper proposes a wide argumentation about the measurement uncertainty and the source of error which is influenced by. After a concise description of the triangulation model and of the basic idea of the system working, the measurement techniques are analyzed both from a static and a dynamic point of view, with a special attention to the uncertainty sources in the two measurement conditions and the possible improvements that may be applied to reduce their influence.

  1. Identification of the feature that causes the I-band secondary maximum of a Type Ia supernova

    NASA Astrophysics Data System (ADS)

    Jack, D.; Baron, E.; Hauschildt, P. H.

    2015-06-01

    We obtained a time series of spectra covering the secondary maximum in the I band of the bright Type Ia supernova 2014J in M82 with the TIGRE telescope. Comparing the observations with theoretical models calculated with the time dependent extension of the PHOENIX code, we identify the feature that causes the secondary maximum in the I-band light curve. Fe II 3d6(3D)4s-3d6(5D)4p and similar high-excitation transitions produce a blended feature at ˜7500 Å, which causes the rise of the light curve towards the secondary maximum. The series of observed spectra of SN 2014J and archival data of SN 2011fe confirm this conclusion. We further studied the plateau phase of the R-band light curve of SN 2014J and searched for features which contribute to the flux. The theoretical models do not clearly indicate a new feature that may cause the R-band plateau phase. However, Co II features in the range of 6500-7000 Å and the Fe II feature of the I band are clearly seen in the theoretical spectra, but do not appear to provide all of the flux necessary for the R-band plateau.

  2. Dynamic-Feature Extraction, Attribution and Reconstruction (DEAR) Method for Power System Model Reduction

    SciTech Connect

    Wang, Shaobu; Lu, Shuai; Zhou, Ning; Lin, Guang; Elizondo, Marcelo A.; Pai, M. A.

    2014-09-04

    In interconnected power systems, dynamic model reduction can be applied on generators outside the area of interest to mitigate the computational cost with transient stability studies. This paper presents an approach of deriving the reduced dynamic model of the external area based on dynamic response measurements, which comprises of three steps, dynamic-feature extraction, attribution and reconstruction (DEAR). In the DEAR approach, a feature extraction technique, such as singular value decomposition (SVD), is applied to the measured generator dynamics after a disturbance. Characteristic generators are then identified in the feature attribution step for matching the extracted dynamic features with the highest similarity, forming a suboptimal ‘basis’ of system dynamics. In the reconstruction step, generator state variables such as rotor angles and voltage magnitudes are approximated with a linear combination of the characteristic generators, resulting in a quasi-nonlinear reduced model of the original external system. Network model is un-changed in the DEAR method. Tests on several IEEE standard systems show that the proposed method gets better reduction ratio and response errors than the traditional coherency aggregation methods.

  3. Thinking Can Cause Forgetting: Memory Dynamics in Creative Problem Solving

    ERIC Educational Resources Information Center

    Storm, Benjamin C.; Angello, Genna; Bjork, Elizabeth Ligon

    2011-01-01

    Research on retrieval-induced forgetting has shown that retrieval can cause the forgetting of related or competing items in memory (Anderson, Bjork, & Bjork, 1994). In the present research, we examined whether an analogous phenomenon occurs in the context of creative problem solving. Using the Remote Associates Test (RAT; Mednick, 1962), we found…

  4. Dynamics of diastolic sounds caused by partially occluded coronary arteries.

    PubMed

    Akay, Metin; Akay, Yasemin M; Gauthier, Dominique; Paden, Robert G; Pavlicek, William; Fortuin, F David; Sweeney, John P; Lee, Richard W

    2009-02-01

    The aim of this project is to improve the detection of coronary occlusions using an approach based on the recording and analysis of isolated diastolic heart sounds associated with turbulent blood flow in occluded coronary arteries. The nonlinear dynamic analysis method based on approximate entropy has been proposed for the analysis of diastolic heart sounds. A commercially available electronic stethoscope was used to record the diastolic heart sounds from patients diagnosed with or without coronary artery disease (CAD) based on their coronary angiography examination. The nonlinear dynamical analysis (approximate entropy) measures of the diastolic heart sounds recorded from 30 patients with coronary occlusions and ten normal subjects were estimated. Results suggest the presence of the high nonlinear (approximate entropy) values of diastolic heart sounds associated with CAD (p < 0.05). This approach led to a sensitivity of 77%, a specificity of 80%, and an overall accuracy of 78%. As a summary, 23 out of 30 abnormal patients and eight out of ten normal patients were correctly detected. PMID:19272945

  5. Ambient response of a unique performance-based design building with dynamic response modification features

    USGS Publications Warehouse

    Celebi, Mehmet; Huang, Moh; Shakal, Antony; Hooper, John; Klemencic, Ron

    2012-01-01

    A 64-story, performance-based design building with reinforced concrete core shear-walls and unique dynamic response modification features (tuned liquid sloshing dampers and buckling-restrained braces) has been instrumented with a monitoring array of 72 channels of accelerometers. Ambient vibration data recorded are analyzed to identify modes and associated frequencies and damping. The low-amplitude dynamic characteristics are considerably different than those computed from design analyses, but serve as a baseline against which to compare with future strong shaking responses. Such studies help to improve our understanding of the effectiveness of the added features to the building and help improve designs in the future.

  6. Short-Time Glassy-like Dynamics Observed in Viscous Protein Solutions with Competing Potential Features

    NASA Astrophysics Data System (ADS)

    Wagner, Norman; Godfrin, Doug; Liu, Yun

    Structures in concentrated protein solutions caused by the combination of short-range attraction (SA) and long-range repulsion (LR) have been extensively studied due to their importance in understanding therapeutic protein formulations and the phase behavior in general. Despite extensive studies of kinetically arrested states in colloidal systems with short-range attraction, less is understood for the effect of an additional longer-range repulsion on model colloidal systems with a SA interaction. Highly purified lysozyme is used a model experimental system due to its stable globular structure and SALR interactions at low ionic strength that can be quantitatively modeled. The fluid microstructure and protein short time self diffusion are measured across a broad range of conditions by small angle neutron scattering (SANS) and neutron spin echo (NSE), respectively. Newtonian liquid behavior is observed at all concentrations, even with an increase of zero shear viscosity by almost four orders of magnitude with increasing concentration. However, dynamic measurements demonstrate a sub-diffusive regime at relatively short time scales for concentrated samples at low temperature. The formation of a heterogeneous density distribution is shown to produce localized regions of high density that reduce protein motion, giving it a glassy-like behavior at the short time scale. This heterogeneity occurs at the length scale associated with the intermediate range order driven by the competing potential features, distinguishable from heterogeneous colloidal gels.

  7. Visuospatial cueing by self-caused features: Orienting of attention and action-outcome associative learning.

    PubMed

    Gozli, Davood G; Aslam, Hira; Pratt, Jay

    2016-04-01

    The effect of a salient visual feature in orienting spatial attention was examined as a function of the learned association between the visual feature and the observer's action. During an initial acquisition phase, participants learned that two keypress actions consistently produced red and green visual cues. Next, in a test phase, participants' actions continued to result in singletons, but their color could be either congruent or incongruent with the learned action-color associations. Furthermore, the color singletons now functioned as valid or invalid spatial cues in a visual search, in which participants looked for a tilted line ("/" or "\\") among distractors ("X"s). The results showed that an action-congruent color was more effective as a valid cue in the search task (increased benefit), but less effective as an invalid cue (reduced cost). We discuss our findings in terms of both an inhibition account and a preactivation account of action-driven sensory bias, and argue in favor of the preactivation account. PMID:26228183

  8. De Novo Mutation in ABCC9 Causes Hypertrichosis Acromegaloid Facial Features Disorder.

    PubMed

    Afifi, Hanan H; Abdel-Hamid, Mohamed S; Eid, Maha M; Mostafa, Inas S; Abdel-Salam, Ghada M H

    2016-01-01

    A 13-year-old Egyptian girl with generalized hypertrichosis, gingival hyperplasia, coarse facial appearance, no cardiovascular or skeletal anomalies, keloid formation, and multiple labial frenula was referred to our clinic for counseling. Molecular analysis of the ABCC9 gene showed a de novo missense mutation located in exon 27, which has been described previously with Cantu syndrome. An overlap between Cantu syndrome, acromegaloid facial syndrome, and hypertrichosis acromegaloid facial features disorder is apparent at the phenotypic and molecular levels. The patient reported here gives further evidence that these syndromes are an expression of the ABCC9-related disorders, ranging from hypertrichosis and acromegaloid facies to the severe end of Cantu syndrome. PMID:26871653

  9. Clinical Features and Outcomes of Spontaneous Bacterial Peritonitis Caused by Streptococcus pneumoniae

    PubMed Central

    Kim, Taeeun; Hong, Sun In; Park, Se Yoon; Jung, Jiwon; Chong, Yong Pil; Kim, Sung-Han; Lee, Sang-Oh; Kim, Yang Soo; Woo, Jun Hee; Lim, Young-Suk; Sung, Heungsup; Kim, Mi-Na; Choi, Sang-Ho

    2016-01-01

    Abstract Streptococcus pneumoniae is a well-known cause of spontaneous bacterial peritonitis (SBP) in cirrhotic patients. However, little information is available regarding clinical characteristics and outcomes of SBP caused by S. pneumoniae. It has been suggested that spontaneous pneumococcal peritonitis (SPP) often spreads hematogenously from concomitant pneumococcal pneumonia, and is associated with a higher rate of mortality. During the period between January 1997 and December 2013, 50 SPP cases were identified. These cases were then age/sex-matched with 100 patients with SBP due to causes other than S. pneumoniae (controls). SPP accounted for 4.3% (50/1172) of all culture-proven SBPs. The baseline Child-Pugh class, etiology of cirrhosis, and model for end-stage liver disease scores were comparable for the 2 groups. SPP patients were more likely than control patients to have a community-acquired infection (90.0% vs. 76.0%; P = 0.04), concurrent bacteremia (84.0% vs. 59.0%; P = 0.002), and to present with variceal bleeding (10.0% vs. 1.0%; P = 0.02). None of the study patients had pneumococcal pneumonia. The most common initial empirical therapy for both groups was third-generation cephalosporins (96.0% vs. 91.0%; P = 0.34) which was active against a significantly higher proportion of the cases than of the controls (97.8% vs. 78.7%; P = 0.003). Thirty-day mortality was significantly lower in the case group than in the control group (10.0% vs. 24.0%; P = 0.04). SPP was not associated with pneumococcal pneumonia and showed lower mortality than SBP caused by other organisms. However, the present study was constrained by the natural limitations characteristic of a small, retrospective study. Therefore, large-scale, well-controlled studies are required to demonstrate the influence of SPP on mortality, which was marginal in the present study. PMID:27258513

  10. Intracellular Information Processing through Encoding and Decoding of Dynamic Signaling Features

    PubMed Central

    Makadia, Hirenkumar K.; Schwaber, James S.; Vadigepalli, Rajanikanth

    2015-01-01

    Cell signaling dynamics and transcriptional regulatory activities are variable within specific cell types responding to an identical stimulus. In addition to studying the network interactions, there is much interest in utilizing single cell scale data to elucidate the non-random aspects of the variability involved in cellular decision making. Previous studies have considered the information transfer between the signaling and transcriptional domains based on an instantaneous relationship between the molecular activities. These studies predict a limited binary on/off encoding mechanism which underestimates the complexity of biological information processing, and hence the utility of single cell resolution data. Here we pursue a novel strategy that reformulates the information transfer problem as involving dynamic features of signaling rather than molecular abundances. We pursue a computational approach to test if and how the transcriptional regulatory activity patterns can be informative of the temporal history of signaling. Our analysis reveals (1) the dynamic features of signaling that significantly alter transcriptional regulatory patterns (encoding), and (2) the temporal history of signaling that can be inferred from single cell scale snapshots of transcriptional activity (decoding). Immediate early gene expression patterns were informative of signaling peak retention kinetics, whereas transcription factor activity patterns were informative of activation and deactivation kinetics of signaling. Moreover, the information processing aspects varied across the network, with each component encoding a selective subset of the dynamic signaling features. We developed novel sensitivity and information transfer maps to unravel the dynamic multiplexing of signaling features at each of these network components. Unsupervised clustering of the maps revealed two groups that aligned with network motifs distinguished by transcriptional feedforward vs feedback interactions. Our new

  11. Endophthalmitis caused by Pantoea agglomerans: clinical features, antibiotic sensitivities, and outcomes

    PubMed Central

    Venincasa, Vincent D; Kuriyan, Ajay E; Flynn, Harry W; Sridhar, Jayanth; Miller, Darlene

    2015-01-01

    Purpose To report the clinical findings, antibiotic sensitivities, and visual outcomes associated with endophthalmitis caused by Pantoea agglomerans. Methods A consecutive case series of patients with vitreous culture-positive endophthalmitis caused by P. agglomerans from January 1, 1990 to December 31, 2012 at a large university referral center. Findings from the current study were compared to prior published studies. Results Of the three study patients that were identified, clinical settings included trauma (n=2) and post-cataract surgery (n=1). Presenting visual acuity was hand motion or worse in all three cases. All isolates were sensitive to ceftazidime, gentamicin, imipenem, and fluoroquinolones. All isolates were resistant to ampicillin. Initial treatment strategies were vitreous tap and intravitreal antibiotic injection (n=1) and pars plana vitrectomy with intravitreal antibiotic injection (n=2). At last follow-up, one patient had no light perception vision, while the other two had best-corrected visual acuity of 20/200 and 20/400. Conclusion All Pantoea isolates were sensitive to ceftazidime, gentamicin, imipenem, and fluoroquinolones. All patients in the current study received at least one intravitreal antibiotic to which P. agglomerans was shown to be sensitive in vitro. In spite of this, the visual outcomes were generally poor. PMID:26185411

  12. Duplication of the TGFBR1 gene causes features of Loeys-Dietz syndrome.

    PubMed

    Breckpot, Jeroen; Budts, Werner; De Zegher, Francis; Vermeesch, Joris R; Devriendt, Koenraad

    2010-01-01

    Loeys-Dietz syndrome (LDS; OMIM:609192) is an autosomal dominant disorder characterized by hypertelorism, bifid uvula or cleft palate, and arterial tortuosity with widespread vascular aneurysms and a high risk of aortic dissection at an early age. LDS results from mutations in the transforming growth factor beta-receptor I and II (TGFBR1 and TGFBR2) genes, altering the transmission of the subcellular TGF-β signal, mediated by increased activation of Smad2. We report on a 17-year-old boy with pubertas tarda, a bifid uvula, camptodactyly and facial dysmorphic features, suggestive of LDS. Mutation analysis of TGFBR1 and TGFBR2 was normal. By means of molecular karyotyping two previously unreported chromosomal imbalances were detected: a 120 kb deletion on chromosome 22q13.31q13.32, inherited from an unaffected parent, and a de novo 14.6 Mb duplication on chromosome 9q22.32q31.3, comprising TGFBR1. We hypothesize that copy number gain of TGFBR1 contributes to the phenotype. PMID:20813212

  13. Mutations in SPRTN cause early onset hepatocellular carcinoma, genomic instability and progeroid features.

    PubMed

    Lessel, Davor; Vaz, Bruno; Halder, Swagata; Lockhart, Paul J; Marinovic-Terzic, Ivana; Lopez-Mosqueda, Jaime; Philipp, Melanie; Sim, Joe C H; Smith, Katherine R; Oehler, Judith; Cabrera, Elisa; Freire, Raimundo; Pope, Kate; Nahid, Amsha; Norris, Fiona; Leventer, Richard J; Delatycki, Martin B; Barbi, Gotthold; von Ameln, Simon; Högel, Josef; Degoricija, Marina; Fertig, Regina; Burkhalter, Martin D; Hofmann, Kay; Thiele, Holger; Altmüller, Janine; Nürnberg, Gudrun; Nürnberg, Peter; Bahlo, Melanie; Martin, George M; Aalfs, Cora M; Oshima, Junko; Terzic, Janos; Amor, David J; Dikic, Ivan; Ramadan, Kristijan; Kubisch, Christian

    2014-11-01

    Age-related degenerative and malignant diseases represent major challenges for health care systems. Elucidation of the molecular mechanisms underlying carcinogenesis and age-associated pathologies is thus of growing biomedical relevance. We identified biallelic germline mutations in SPRTN (also called C1orf124 or DVC1) in three patients from two unrelated families. All three patients are affected by a new segmental progeroid syndrome characterized by genomic instability and susceptibility toward early onset hepatocellular carcinoma. SPRTN was recently proposed to have a function in translesional DNA synthesis and the prevention of mutagenesis. Our in vivo and in vitro characterization of identified mutations has uncovered an essential role for SPRTN in the prevention of DNA replication stress during general DNA replication and in replication-related G2/M-checkpoint regulation. In addition to demonstrating the pathogenicity of identified SPRTN mutations, our findings provide a molecular explanation of how SPRTN dysfunction causes accelerated aging and susceptibility toward carcinoma. PMID:25261934

  14. Relationship between the clinical features of neurological decompression illness and its causes.

    PubMed

    Wilmshurst, P; Bryson, P

    2000-07-01

    There is dispute as to whether paradoxical gas embolism is an important aetiological factor in neurological decompression illness, particularly when the spinal cord is affected. We performed a blind case-controlled study to determine the relationship between manifestations of neurological decompression illness and causes in 100 consecutive divers with neurological decompression illness and 123 unaffected historical control divers. The clinical effects of neurological decompression illness (including the sites of lesions and latency of onset) were correlated with the presence of right-to-left shunts, lung disease and a provocative dive profile. The prevalence and size of shunts determined by contrast echocardiography were compared in affected divers and controls. Right-to-left shunts, particularly those which were large and present without a Valsalva manoeuvre, were significantly more common in divers who had neurological decompression illness than in controls (P<0.001). Shunts graded as large or medium in size were present in 52% of affected divers and 12.2% of controls (P<0.001). Spinal decompression illness occurred in 26 out of 52 divers with large or medium shunts and in 12 out of 48 without (P<0.02). The distribution of latencies of symptoms differed markedly in the 52 divers with a large or medium shunt and in the 30 divers who had lung disease or a provocative dive profile. In most cases of neurological decompression illness the cause can be determined by taking a history of the dive profile and latency of onset, and by performing investigations to detect a right-to-left shunt and lung disease. Using this information it is possible to advise divers on the risk of returning to diving and on ways of reducing the risk if diving is resumed. Most cases of spinal decompression illness are associated with a right-to-left shunt. PMID:10887059

  15. Dynamic frequency feature selection based approach for classification of motor imageries.

    PubMed

    Luo, Jing; Feng, Zuren; Zhang, Jun; Lu, Na

    2016-08-01

    Electroencephalography (EEG) is one of the most popular techniques to record the brain activities such as motor imagery, which is of low signal-to-noise ratio and could lead to high classification error. Therefore, selection of the most discriminative features could be crucial to improve the classification performance. However, the traditional feature selection methods employed in brain-computer interface (BCI) field (e.g. Mutual Information-based Best Individual Feature (MIBIF), Mutual Information-based Rough Set Reduction (MIRSR) and cross-validation) mainly focus on the overall performance on all the trials in the training set, and thus may have very poor performance on some specific samples, which is not acceptable. To address this problem, a novel sequential forward feature selection approach called Dynamic Frequency Feature Selection (DFFS) is proposed in this paper. The DFFS method emphasized the importance of the samples that got misclassified while only pursuing high overall classification performance. In the DFFS based classification scheme, the EEG data was first transformed to frequency domain using Wavelet Packet Decomposition (WPD), which is then employed as the candidate set for further discriminatory feature selection. The features are selected one by one in a boosting manner. After one feature being selected, the importance of the correctly classified samples based on the feature will be decreased, which is equivalent to increasing the importance of the misclassified samples. Therefore, a complement feature to the current features could be selected in the next run. The selected features are then fed to a classifier trained by random forest algorithm. Finally, a time series voting-based method is utilized to improve the classification performance. Comparisons between the DFFS-based approach and state-of-art methods on BCI competition IV data set 2b have been conducted, which have shown the superiority of the proposed algorithm. PMID:27253616

  16. Remote suspect identification and the impact of demographic features on keystroke dynamics

    NASA Astrophysics Data System (ADS)

    Dora, Robert A.; Schalk, Patrick D.; McCarthy, John E.; Young, Scott A.

    2013-05-01

    This paper describes the research, development, and analysis performed during the Remote Suspect Identification (RSID) effort. The effort produced a keystroke dynamics sensor capable of authenticating, continuously verifying, and identifying masquerading users with equal error rates (EER) of approximately 0.054, 0.050, and 0.069, respectively. This sensor employs 11 distinct algorithms, each using between one and five keystroke features, that are fused (across features and algorithms) using a weighted majority ballot algorithm to produce rapid and accurate measurements. The RSID sensor operates discretely, quickly (using few keystrokes), and requires no additional hardware. The researchers also analyzed the difference in sensor performance across 10 demographic features using a keystroke dynamics dataset consisting of data from over 2,200 subjects. This analysis indicated that there are significant and discernible differences across age groups, ethnicities, language, handedness, height, occupation, sex, typing frequency, and typing style.

  17. Mutations in SPRTN cause early onset hepatocellular carcinoma, genomic instability and progeroid features

    PubMed Central

    Lessel, Davor; Vaz, Bruno; Halder, Swagata; Lockhart, Paul J; Marinovic-Terzic, Ivana; Lopez-Mosqueda, Jaime; Philipp, Melanie; Sim, Joe C H; Smith, Katherine R; Oehler, Judith; Cabrera, Elisa; Freire, Raimundo; Pope, Kate; Nahid, Amsha; Norris, Fiona; Leventer, Richard J; Delatycki, Martin B; Barbi, Gotthold; von Ameln, Simon; Högel, Josef; Degoricija, Marina; Fertig, Regina; Burkhalter, Martin D; Hofmann, Kay; Thiele, Holger; Altmüller, Janine; Nürnberg, Gudrun; Nürnberg, Peter; Bahlo, Melanie; Martin, George M; Aalfs, Cora M; Oshima, Junko; Terzic, Janos; Amor, David J; Dikic, Ivan; Ramadan, Kristijan; Kubisch, Christian

    2015-01-01

    Age-related degenerative and malignant diseases represent major challenges for health care systems. Elucidation of the molecular mechanisms underlying carcinogenesis and age-associated pathologies is thus of growing biomedical relevance. We identified biallelic germline mutations in SPRTN (also called C1orf124 or DVC1)1–7 in three patients from two unrelated families. All three patients are affected by a new segmental progeroid syndrome characterized by genomic instability and susceptibility toward early onset hepatocellular carcinoma. SPRTN was recently proposed to have a function in translesional DNA synthesis and the prevention of mutagenesis1–7. Our in vivo and in vitro characterization of identified mutations has uncovered an essential role for SPRTN in the prevention of DNA replication stress during general DNA replication and in replication-related G2/M-checkpoint regulation. In addition to demonstrating the pathogenicity of identified SPRTN mutations, our findings provide a molecular explanation of how SPRTN dysfunction causes accelerated aging and susceptibility toward carcinoma. PMID:25261934

  18. Adaptation to second order stimulus features by electrosensory neurons causes ambiguity

    PubMed Central

    Zhang, Zhubo D.; Chacron, Maurice J.

    2016-01-01

    Understanding the coding strategies used to process sensory input remains a central problem in neuroscience. Growing evidence suggests that sensory systems process natural stimuli efficiently by ensuring a close match between neural tuning and stimulus statistics through adaptation. However, adaptation causes ambiguity as the same response can be elicited by different stimuli. The mechanisms by which the brain resolves ambiguity remain poorly understood. Here we investigated adaptation in electrosensory pyramidal neurons within different parallel maps in the weakly electric fish Apteronotus leptorhynchus. In response to step increases in stimulus variance, we found that pyramidal neurons within the lateral segment (LS) displayed strong scale invariant adaptation whereas those within the centromedial segment (CMS) instead displayed weaker degrees of scale invariant adaptation. Signal detection analysis revealed that strong adaptation in LS neurons significantly reduced stimulus discriminability. In contrast, weaker adaptation displayed by CMS neurons led to significantly lesser impairment of discriminability. Thus, while LS neurons display adaptation that is matched to natural scene statistics, thereby optimizing information transmission, CMS neurons instead display weaker adaptation and would instead provide information about the context in which these statistics occur. We propose that such a scheme is necessary for decoding by higher brain structures. PMID:27349635

  19. Dynamics and distribution of natural and human-caused hypoxia

    NASA Astrophysics Data System (ADS)

    Rabalais, N. N.; Díaz, R. J.; Levin, L. A.; Turner, R. E.; Gilbert, D.; Zhang, J.

    2010-02-01

    Water masses can become undersaturated with oxygen when natural processes alone or in combination with anthropogenic processes produce enough organic carbon that is aerobically decomposed faster than the rate of oxygen re-aeration. The dominant natural processes usually involved are photosynthetic carbon production and microbial respiration. The re-supply rate is indirectly related to its isolation from the surface layer. Hypoxic water masses (<2 mg L-1, or approximately 30% saturation) can form, therefore, under "natural" conditions, and are more likely to occur in marine systems when the water residence time is extended, water exchange and ventilation are minimal, stratification occurs, and where carbon production and export to the bottom layer are relatively high. Hypoxia has occurred through geological time and naturally occurs in oxygen minimum zones, deep basins, eastern boundary upwelling systems, and fjords. Hypoxia development and continuation in many areas of the world's coastal ocean is accelerated by human activities, especially where nutrient loading increased in the Anthropocene. This higher loading set in motion a cascading set of events related to eutrophication. The formation of hypoxic areas has been exacerbated by any combination of interactions that increase primary production and accumulation of organic carbon leading to increased respiratory demand for oxygen below a seasonal or permanent pycnocline. Nutrient loading is likely to increase further as population growth and resource intensification rises, especially with increased dependency on crops using fertilizers, burning of fossil fuels, urbanization, and waste water generation. It is likely that the occurrence and persistence of hypoxia will be even more widespread and have more impacts than presently observed. Global climate change will further complicate the causative factors in both natural and human-caused hypoxia. The likelihood of strengthened stratification alone, from increased

  20. Compound heterozygous or homozygous truncating MYBPC3 mutations cause lethal cardiomyopathy with features of noncompaction and septal defects

    PubMed Central

    Wessels, Marja W; Herkert, Johanna C; Frohn-Mulder, Ingrid M; Dalinghaus, Michiel; van den Wijngaard, Arthur; de Krijger, Ronald R; Michels, Michelle; de Coo, Irenaeus FM; Hoedemaekers, Yvonne M; Dooijes, Dennis

    2015-01-01

    Familial hypertrophic cardiomyopathy (HCM) is usually caused by autosomal dominant pathogenic mutations in genes encoding sarcomeric or sarcomere-associated cardiac muscle proteins. The disease mainly affects adults, although young children with severe HCM have also been reported. We describe four unrelated neonates with lethal cardiomyopathy, and performed molecular studies to identify the genetic defect. We also present a literature overview of reported patients with compound heterozygous or homozygous pathogenic MYBPC3 mutations and describe their clinical characteristics. All four children presented with feeding difficulties, failure to thrive, and dyspnea. They died from cardiac failure before age 13 weeks. Features of left ventricular noncompaction were diagnosed in three patients. In the fourth, hypertrabeculation was not a clear feature, but could not be excluded. All of them had septal defects. Two patients were compound heterozygotes for the pathogenic c.2373dup p.(Trp792fs) and c.2827C>T p.(Arg943*) mutations, and two were homozygous for the c.2373dup and c.2827C>T mutations. All patients with biallelic truncating pathogenic mutations in MYBPC3 reported so far (n=21) were diagnosed with severe cardiomyopathy and/or died within the first few months of life. In 62% (13/21), septal defects or a patent ductus arteriosus accompanied cardiomyopathy. In contrast to heterozygous pathogenic mutations, homozygous or compound heterozygous truncating pathogenic MYBPC3 mutations cause severe neonatal cardiomyopathy with features of left ventricular noncompaction and septal defects in approximately 60% of patients. PMID:25335496

  1. Study of features based on nonlinear dynamical modeling in ECG arrhythmia detection and classification.

    PubMed

    Owis, Mohamed I; Abou-Zied, Ahmed H; Youssef, Abou-Bakr M; Kadah, Yasser M

    2002-07-01

    We present a study of the nonlinear dynamics of electrocardiogram (ECG) signals for arrhythmia characterization. The correlation dimension and largest Lyapunov exponent are used to model the chaotic nature of five different classes of ECG signals. The model parameters are evaluated for a large number of real ECG signals within each class and the results are reported. The presented algorithms allow automatic calculation of the features. The statistical analysis of the calculated features indicates that they differ significantly between normal heart rhythm and the different arrhythmia types and, hence, can be rather useful in ECG arrhythmia detection. On the other hand, the results indicate that the discrimination between different arrhythmia types is difficult using such features. The results of this work are supported by statistical analysis that provides a clear outline for the potential uses and limitations of these features. PMID:12083309

  2. Catastrophic volcanism as a cause of shocked features found at the K/T boundary and in cryptoexplosion structures

    NASA Technical Reports Server (NTRS)

    Loper, D. E.; Mccartney, K.

    1988-01-01

    The presence of quartz grains containing shock lamellae at the Cretaceous/Tertiary (K/T) boundary is viewed by many as the single most compelling evidence of meteoritic or cometary impact because there is no known endogenous mechanism for producing these features. Similarly the presence of shocked quartz, shatter cones, coesite and stishovite at cryptoexplosion structures is comonly taken as conclusive evidence of impact. However, several recent studies have cast doubt on this interpretation. It is argued that basaltic volcanism, although not normally explosive, can under exceptional circumstances produce overpressures sufficiently high to produce shock features. The exceptional circumstances include a high content of volatiles, usually CO2, and no preestablished pathway to the surface. Rapid cooling of the saturated basaltic magma can occur if it underlies a cooler more evolved magma in a chamber. Initial slow cooling and partial exsolution of the volatiles will cause the density of the basaltic magma to become less than that of the overlying magma, leading to overturning and mixing. Gas will escape the magma chamber along planar cracks once the pressure becomes sufficiently high. In the vicinity of the crack tip there is a smallscale deviatoric stress pattern which is thought to be sufficiently high to produce transient cracks along secondary axes in the quartz crystals, causing the planar features. The CO2-rich fluid inclusions which have been found along planar elements of quartz in basement rocks of the Vredefort Dome were likely to have been emplaced by such a process. If the mechanism described is capable of producing shocked features as above, it would require a reassessment of the origin of many cryptoexplosion structures as well as seriously weakening the case for an impact origin of the K/T event.

  3. Multifractal features of magnetospheric dynamics and their dependence on solar activity

    NASA Astrophysics Data System (ADS)

    Gopinath, Sumesh

    2016-09-01

    In the present study, novel wavelet leaders (WL) based multifractal analysis has been used to get a better knowledge of the self-organization phenomena inherent in complex magnetospheric dynamics during disturbance and quiescent periods, focusing mainly on the intermittent features of auroral electrojet (AE) index. The results derived from the analysis certainly exhibit the phase transition property of magnetosphere system with respect to variabilities in the driving conditions. By using the novel WL method, solar activity dependence/independence of intermittency of magnetospheric proxies such as AE, SYM-H and Dst indices have been compared. The results indicate that the multifractality of AE index does not follow the solar activity cycle while intermittent features of SYM-H and Dst indices show high degree of solar activity dependence. This shows that along with the external solar wind perturbations, certain complex phenomena of internal origin also significantly modulate the dynamics of geomagnetic fluctuations in the auroral region.

  4. A Combination of Vocal Frequency Dynamic and Summary Features Discriminates between Three Pragmatic Categories of Infant-Directed Speech.

    ERIC Educational Resources Information Center

    Katz, Gary S.; And Others

    1996-01-01

    Assessed the relative contribution of dynamic and summary features of vocal frequency to the discrimination of pragmatic categories in infant-directed speech. Forty-nine mothers were instructed to use their voice to get their infant's attention, show approval, and provide comfort. Findings suggest that both dynamic and summary features are…

  5. Functional MRI mapping of dynamic visual features during natural viewing in the macaque.

    PubMed

    Russ, Brian E; Leopold, David A

    2015-04-01

    The ventral visual pathway of the primate brain is specialized to respond to stimuli in certain categories, such as the well-studied face selective patches in the macaque inferotemporal cortex. To what extent does response selectivity determined using brief presentations of isolated stimuli predict activity during the free viewing of a natural, dynamic scene, where features are superimposed in space and time? To approach this question, we obtained fMRI activity from the brains of three macaques viewing extended video clips containing a range of social and nonsocial content and compared the fMRI time courses to a family of feature models derived from the movie content. Starting with more than two dozen feature models extracted from each movie, we created functional maps based on features whose time courses were nearly orthogonal, focusing primarily on faces, motion content, and contrast level. Activity mapping using the face feature model readily yielded functional regions closely resembling face patches obtained using a block design in the same animals. Overall, the motion feature model dominated responses in nearly all visually driven areas, including the face patches as well as ventral visual areas V4, TEO, and TE. Control experiments presenting dynamic movies, whose content was free of animals, demonstrated that biological movement critically contributed to the predominance of motion in fMRI responses. These results highlight the value of natural viewing paradigms for studying the brain's functional organization and also underscore the paramount contribution of magnocellular input to the ventral visual pathway during natural vision. PMID:25579448

  6. Functional MRI mapping of dynamic visual features during natural viewing in the macaque

    PubMed Central

    Russ, Brian E.; Leopold, David A.

    2015-01-01

    The ventral visual pathway of the primate brain is specialized to respond to stimuli in certain categories, such as the well-studied face selective patches in the macaque inferotemporal cortex. To what extent does response selectivity determined using brief presentations of isolated stimuli predict activity during the free viewing of a natural, dynamic scene, where features are superimposed in space and time? To approach this question, we obtained fMRI activity from the brains of three macaques viewing extended video clips containing a range of social and nonsocial content and compared the fMRI time courses to a family of feature models derived from the movie content. Starting with more than two dozen feature models extracted from each movie, we created functional maps based on features whose time courses were nearly orthogonal, focusing primarily on faces, motion content, and contrast level. Activity mapping using the face feature model readily yielded functional regions closely resembling face patches obtained using a block design in the same animals. Overall, the motion feature model dominated responses in nearly all visually driven areas, including the face patches as well as ventral visual areas V4, TEO, and TE. Control experiments presenting dynamic movies, whose content was free of animals, demonstrated that biological movement critically contributed to the predominance of motion in fMRI responses. These results highlight the value of natural viewing paradigms for studying the brain’s functional organization and also underscore the paramount contribution of magnocellular input to the ventral visual pathway during natural vision. PMID:25579448

  7. A Study On Surges: I. Automatic Detection Of Dynamic Hα Dark Features From High-Cadence Full-Disk Observations

    NASA Astrophysics Data System (ADS)

    Liu, Y.; Kurokawa, H.; Kitai, R.; Ueno, S.; Su, J. T.

    2005-05-01

    We present a new method for the automatic identification and classification of dynamic Hα dark features found in time series of full-disk solar images at three Hα wavelengths (center, and ± 0.8 Å). The simultaneous Hα observations are obtained by the multi-channel Flare Monitoring Telescope (FMT) at Hida Observatory. The program was developed in order to replace the present visual detection and classification of the phenomena. Usually, an obvious dark feature found in the Hα -0.8 Å observations probably corresponds to some phenomenon such as a surge or chromospheric network enhancement, or filament activity. Thus, one of our aims in this program is to distinguish each phenomenon by its own properties and key parameters. We optimized the threshold values of the key parameters such as the area and darkness of the transiently darkening features in Hα -0.8 Å so that the computer can reasonably identify surges and filament activations. In comparison, for a 7-day observation period, the number of dark events detected by the program contains 89% of the events recognized visually. However, 10 times more events are detected automatically. The missing events are mainly caused by the deletion of data with poor visibility. It is found that the dark events can be identified with more precise starting and ending times by a machine than by a human. Some statistical studies of surges or other activities can be carried out based on the computer-produced database. With some modifications the program can be applied to monitor real-time dynamic features on disk, including flare ribbons.

  8. Temporal and spatial dynamics of scaling-specific features of a gene regulatory network in Drosophila

    PubMed Central

    Wu, Honggang; Manu; Jiao, Renjie; Ma, Jun

    2015-01-01

    A widely appreciated aspect of developmental robustness is pattern formation in proportion to size. But how such scaling features emerge dynamically remains poorly understood. Here we generate a data set of the expression profiles of six gap genes in Drosophila melanogaster embryos that differ significantly in size. Expression patterns exhibit size-dependent dynamics both spatially and temporally. We uncover a dynamic emergence of under-scaling in the posterior, accompanied by reduced expression levels of gap genes near the middle of large embryos. Simulation results show that a size-dependent Bicoid gradient input can lead to reduced Krüppel expression that can have long-range and dynamic effects on gap gene expression in the posterior. Thus, for emergence of scaled patterns, the entire embryo may be viewed as a single unified dynamic system where maternally derived size-dependent information interpreted locally can be propagated in space and time as governed by the dynamics of a gene regulatory network. PMID:26644070

  9. Dynamic feature analysis of vector-based images for neuropsychological testing

    NASA Astrophysics Data System (ADS)

    Smith, Stephen L.; Cervantes, Basilio R.

    1998-07-01

    The dynamic properties of human motor activities, such as those observed in the course of drawing simple geometric shapes, are considerably more complex and often more informative than the goal to be achieved; in this case a static line drawing. This paper demonstrates how these dynamic properties may be used to provide a means of assessing a patient's visuo-spatial ability -- an important component of neuropsychological testing. The work described here provides a quantitative assessment of visuo-spatial ability, whilst preserving the conventional test environment. Results will be presented for a clinical population of long-term haemodialysis patients and test population comprises three groups of children (1) 7-8 years, (2) 9-10 years and (3) 11-12 years, all of which have no known neurological dysfunction. Ten new dynamic measurements extracted from patient responses in conjunction with one static feature deduced from earlier work describe a patient's visuo-spatial ability in a quantitative manner with sensitivity not previously attainable. The dynamic feature measurements in isolation provide a unique means of tracking a patient's approach to motor activities and could prove useful in monitoring a child' visuo-motor development.

  10. DNA hypomethylation causes bile duct defects in zebrafish and is a distinguishing feature of infantile biliary atresia

    PubMed Central

    Matthews, Randolph P.; EauClaire, Steven F.; Mugnier, Monica; Lorent, Kristin; Cui, Shuang; Ross, Megan M.; Zhang, Zhe; Russo, Pierre; Pack, Michael

    2010-01-01

    Summary Infantile cholestatic disorders arise in the context of progressively developing intrahepatic bile ducts. Biliary atresia (BA), a progressive fibroinflammatory disorder of extra- and intrahepatic bile ducts, is the most common identifiable cause of infantile cholestasis and the leading indication for liver transplantation in children. The etiology of BA is unclear, and while there is some evidence for viral, toxic, and complex genetic causes, the exclusive occurrence of BA during a period of biliary growth and remodeling suggests an importance of developmental factors. Interestingly, interferon-γ (IFNγ) signaling is activated in patients and in the frequently utilized Rhesus rotavirus mouse model of BA, and is thought to play a key mechanistic role. Here we demonstrate intrahepatic biliary defects and upregulated hepatic expression of IFNγ pathway genes caused by genetic or pharmacological inhibition of DNA methylation in zebrafish larvae. Biliary defects elicited by inhibition of DNA methylation were reversed by treatment with glucocorticoid, suggesting that the activation of inflammatory pathways was critical. DNA methylation was significantly reduced in bile duct cells from BA patients compared to patients with other infantile cholestatic disorders, thereby establishing a possible etiologic link between decreased DNA methylation, activation of IFNγ signaling, and biliary defects in patients. Conclusion: Inhibition of DNA methylation leads to biliary defects and activation of IFNγ-responsive genes, thus sharing features with BA, which we determine to be associated with DNA hypomethylation. We propose epigenetic activation of IFNγ signaling as a common etiologic mechanism of intrahepatic bile duct defects in BA. PMID:21319190

  11. Textural kinetics: a novel dynamic contrast-enhanced (DCE)-MRI feature for breast lesion classification.

    PubMed

    Agner, Shannon C; Soman, Salil; Libfeld, Edward; McDonald, Margie; Thomas, Kathleen; Englander, Sarah; Rosen, Mark A; Chin, Deanna; Nosher, John; Madabhushi, Anant

    2011-06-01

    Dynamic contrast-enhanced (DCE)-magnetic resonance imaging (MRI) of the breast has emerged as an adjunct imaging tool to conventional X-ray mammography due to its high detection sensitivity. Despite the increasing use of breast DCE-MRI, specificity in distinguishing malignant from benign breast lesions is low, and interobserver variability in lesion classification is high. The novel contribution of this paper is in the definition of a new DCE-MRI descriptor that we call textural kinetics, which attempts to capture spatiotemporal changes in breast lesion texture in order to distinguish malignant from benign lesions. We qualitatively and quantitatively demonstrated on 41 breast DCE-MRI studies that textural kinetic features outperform signal intensity kinetics and lesion morphology features in distinguishing benign from malignant lesions. A probabilistic boosting tree (PBT) classifier in conjunction with textural kinetic descriptors yielded an accuracy of 90%, sensitivity of 95%, specificity of 82%, and an area under the curve (AUC) of 0.92. Graph embedding, used for qualitative visualization of a low-dimensional representation of the data, showed the best separation between benign and malignant lesions when using textural kinetic features. The PBT classifier results and trends were also corroborated via a support vector machine classifier which showed that textural kinetic features outperformed the morphological, static texture, and signal intensity kinetics descriptors. When textural kinetic attributes were combined with morphologic descriptors, the resulting PBT classifier yielded 89% accuracy, 99% sensitivity, 76% specificity, and an AUC of 0.91. PMID:20508965

  12. Different developmental trajectories across feature types support a dynamic field model of visual working memory development

    PubMed Central

    Simmering, Vanessa R.; Miller, Hilary E.; Bohache, Kevin

    2015-01-01

    Research on visual working memory has focused on characterizing the nature of capacity limits as “slots” or “resources” based almost exclusively on adults’ performance with little consideration for developmental change. Here we argue that understanding how visual working memory develops can shed new light onto the nature of representations. We present an alternative model, the Dynamic Field Theory (DFT), which can capture effects that have been previously attributed either to “slot” or “resource” explanations. The DFT includes a specific developmental mechanism to account for improvements in both resolution and capacity of visual working memory throughout childhood. Here we show how development in the DFT can account for different capacity estimates across feature types (i.e., color and shape). The current paper tests this account by comparing children’s (3, 5, and 7 years of age) performance across different feature types. Results showed that capacity for colors increased faster over development than capacity for shapes. A second experiment confirmed this difference across feature types within subjects, but also showed that the difference can be attenuated by testing memory for less-familiar colors. Model simulations demonstrate how developmental changes in connectivity within the model—purportedly arising through experience—can capture differences across feature types. PMID:25737253

  13. Docking Studies and Molecular Dynamic Simulations Reveal Different Features of IDO1 Structure.

    PubMed

    Greco, Francesco Antonio; Bournique, Answald; Coletti, Alice; Custodi, Chiara; Dolciami, Daniela; Carotti, Andrea; Macchiarulo, Antonio

    2016-09-01

    In the last decade, indoleamine 2,3-dioxygenase 1 (IDO1) has attracted a great deal of attention being recognized as key regulator of immunosuppressive pathways in the tumor immuno-editing process. Several classes of inhibitors have been developed as potential anticancer agents, but only few of them have advanced in clinical trials. Hence, the quest of novel potent and selective inhibitors of the enzyme is still active and mostly pursued by structure-based drug design strategies based on early and more recent crystal structures of IDO1. Combining docking studies and molecular dynamic simulations, in this work we have comparatively investigated the structural features of each crystal structure of IDO1. The results pinpoint different features in specific crystal structures of the enzyme that may benefit the medicinal chemistry arena aiding the design of novel potent and selective inhibitors of IDO1. PMID:27546049

  14. Sleep apnoea detection in children using PPG envelope-based dynamic features.

    PubMed

    Sepúlveda-Cano, L M; Gil, E; Laguna, P; Castellanos-Dominguez, G

    2011-01-01

    Photopletysmography signal has been developed for monitoring of Obstructive Sleep Apnoea, in particular, whenever an apneic episode occurs, that is reflected by decreases in the photopletysmography signal amplitude fluctuation. However, other physiological events such as artifacts and deep inspiratory gasp produce sympathetic activation, being unrelated to apnea. Thus, its high sensitivity can produce misdetections and overestimate apneic episodes. In this regard, a methodology for selecting a set of relevant non-stationary features to increase the specificity of the obstructive sleep apnea detector is discussed. A time-evolving version of the standard linear multivariate decomposition is discussed to perform stochastic dimensionality reduction. As a result, performed outcomes of accuracy bring enough evidence that if using a subset of cepstral-based dynamic features, then patient classification accuracy is 83.3%. Therefore, photoplethysmography--based detection provides an adequate scheme for obstructive sleep apnea diagnosis. PMID:22254600

  15. Face processing in autism: Reduced integration of cross-feature dynamics.

    PubMed

    Shah, Punit; Bird, Geoffrey; Cook, Richard

    2016-02-01

    Characteristic problems with social interaction have prompted considerable interest in the face processing of individuals with Autism Spectrum Disorder (ASD). Studies suggest that reduced integration of information from disparate facial regions likely contributes to difficulties recognizing static faces in this population. Recent work also indicates that observers with ASD have problems using patterns of facial motion to judge identity and gender, and may be less able to derive global motion percepts. These findings raise the possibility that feature integration deficits also impact the perception of moving faces. To test this hypothesis, we examined whether observers with ASD exhibit susceptibility to a new dynamic face illusion, thought to index integration of moving facial features. When typical observers view eye-opening and -closing in the presence of asynchronous mouth-opening and -closing, the concurrent mouth movements induce a strong illusory slowing of the eye transitions. However, we find that observers with ASD are not susceptible to this illusion, suggestive of weaker integration of cross-feature dynamics. Nevertheless, observers with ASD and typical controls were equally able to detect the physical differences between comparison eye transitions. Importantly, this confirms that observers with ASD were able to fixate the eye-region, indicating that the striking group difference has a perceptual, not attentional origin. The clarity of the present results contrasts starkly with the modest effect sizes and equivocal findings seen throughout the literature on static face perception in ASD. We speculate that differences in the perception of facial motion may be a more reliable feature of this condition. PMID:26756454

  16. Phobos and deimos: Analysis of surface features, ejecta dynamics and a volatile loss mechanism

    NASA Technical Reports Server (NTRS)

    Davis, D. R.; Chapman, C. R.; Greenberg, R.; Weidenschilling, S. J.

    1980-01-01

    The question of whether the crater population on Phobos represents a production population or an equilibrium population is considered. The absolute ages of cratered surfaces are interpreted and analyzed. A computer program was developed to study the dynamics of material ejected from Martian satellites and to investigate the hypothesis that at least some of the extensive set of linear features discovered on the surface of Phobos could be the result of secondary cratering from the Stickney impact. The possibility that Deimos was catastrophically disrupted by a large impact but subsequently reaccreted is considered as well as the probability the Phobos had an impact nearly large enough to disrupt it are also discussed.

  17. Dynamical features and electric field strengths of double layers driven by currents. [in auroras

    NASA Technical Reports Server (NTRS)

    Singh, N.; Thiemann, H.; Schunk, R. W.

    1985-01-01

    In recent years, a number of papers have been concerned with 'ion-acoustic' double layers. In the present investigation, results from numerical simulations are presented to show that the shapes and forms of current-driven double layers evolve dynamically with the fluctuations in the current through the plasma. It is shown that double layers with a potential dip can form even without the excitation of ion-acoustic modes. Double layers in two-and one-half-dimensional simulations are discussed, taking into account the simulation technique, the spatial and temporal features of plasma, and the dynamical behavior of the parallel potential distribution. Attention is also given to double layers in one-dimensional simulations, and electrical field strengths predicted by two-and one-half-dimensional simulations.

  18. Dynamic features analysis for the large-scale logistics system warehouse-out operation

    NASA Astrophysics Data System (ADS)

    Yao, Can-Zhong; Lin, Ji-Nan; Liu, Xiao-Feng; Zheng, Xu-Zhou

    2014-12-01

    In the paper, we research on the behavior dynamics for the large-scale logistics system warehouse-out operation systematically. First, we discover that steel products warehouse-out of different warehouses in a large-scale logistics system can be characterized by burst, and the warehouse-out inter-event time follows the power-law distribution with exponents close to α=2.5, which differs from the two classical models proposed by Barabasi (2005) and Vazquez (2005) respectively. By analyzing the warehouse-out inter-event time distribution of the products in one certain large-scale logistics system, we further discuss burst features and mechanisms of logistics system. Additionally, we find that in population behaviors, burst features can be explained by the priority that rooted in holidays and interior task scheduling. However, warehouse-out behaviors of active individuals do not show any features of burst. Further, we find that warehouse-out quantity of steel products follows Fractal Brownian motion with the HURST exponent higher than 0.5 by means of R/S, which infers that the quantity of products in a logistics system is not only guided by prices in the present market, but also related closely to the previous quantity of warehouse-out. Based on V statistic, we compare memory length of different products in warehouses. Finally, we apply complex networks visibility graphs for further validation of fractal features in a logistics system and find that almost every visibility graph exhibits small-world and scale-free features. Both R/S and complex networks visibility graphs reinforce that the warehouse-out quantity of products in a logistics system is not a random walk process, but contains intrinsic regularities and long-term correlation between present and previous warehouse-out quantity.

  19. Studying the NDVI dynamics features for vegetation monitoring method development in the south of Central Siberia

    NASA Astrophysics Data System (ADS)

    Pugacheva, Irina

    Monitoring of vegetation state can be based on studying their dynamics features. Effective methods of satellite data interpretation using spectral feature distinctions should be applied for this purpose. Studying the time series of Normalized Difference Vegetation Index (NDVI) during growth period is one of such approaches. The analysis of NDVI temporal profile shape allows to identify vegetation objects on satellite image. The NDVI curve transformation regularities during growth period are studied in the process of study carried out. Growth rate in specific phenological phases (growth of vegetative organs; maturation and fruiting) and extreme NDVI values during total growth period are detected. Growth rate is calculated as a NDVI curve slope. The NDVI dynamics of different vegetation types (agricultural crops - wheat, oats, buckwheat; abandoned fields of different age, meadow steppe, stony steppe, feather-grass steppe, flood meadow etc.), located in the south of Central Siberia (Krasnoyarsk krai, Khakasia), has been derived and analyzed. Results of this study are as the basis for developed software, which produces the automatic identification of canopy using Terra Modis satellite measurement data.

  20. Automatic identification of lunar craters based on feature points dynamic supply method

    NASA Astrophysics Data System (ADS)

    An, Yongquan; Wu, Chuanchao; Wang, Zhibin; Wang, Zhaoba

    2015-10-01

    Elevation data obtained by the laser altimeter describes the real lunar topography. Digital elevation modeling and data preprocessing were carried out based on source data published by China National astronomical observatories. The Feature Points Dynamic Supply Method(FPDSM) was proposed. The whole craters were identified on the moon and which characteristic parameters were calculated. Lips details can be distinguished. Light noise of image data and the difficulties to identify irregular boundary of lunar craters were reduced. Number of craters in designated areas were counted and so does the statistic distribution. The Feature Points Dynamic Supply Method was verified from three ways: the relationship between craters density and geological age ,and NASA's statistical results of diameter-frequency, and the data available of some well-known craters. The maximum measurement error of pit center position and diameter are 15.63% and 4.39%. For the angle between the major diameter of fitted ellipse of pit lips and local north direction ,the neighboring pits have the same or similar value.

  1. Site-Specific DNA Structural and Dynamic Features Revealed by Nucleotide-Independent Nitroxide Probes

    SciTech Connect

    Popova, Anna; Kalai, Tamas; Hideg, Kalman; Qin, Peter Z.

    2009-09-15

    In site-directed spin labeling, a covalently attached nitroxide probe containing a chemically inert unpaired electron is utilized to obtain information on the local environment of the parent macromolecule. Studies presented here examine the feasibility of probing local DNA structural and dynamic features using a class of nitroxide probes that are linked to chemically substituted phosphorothioate positions at the DNA backbone. Two members of this family, designated as R5 and R5a, were attached to eight different sites of a dodecameric DNA duplex without severely perturbing the native B-form conformation. Measured X-band electron paramagnetic resonance (EPR) spectra, which report on nitroxide rotational motions, were found to vary depending on the location of the label (e.g., duplex center vs termini) and the surrounding DNA sequence. This indicates that R5 and R5a can provide information on the DNA local environment at the level of an individual nucleotide. As these probes can be attached to arbitrary nucleotides within a nucleic acid sequence, they may provide a means to “scan” a given DNA molecule in order to interrogate its local structural and dynamic features.

  2. Red Lesion Detection Using Dynamic Shape Features for Diabetic Retinopathy Screening.

    PubMed

    Seoud, Lama; Hurtut, Thomas; Chelbi, Jihed; Cheriet, Farida; Langlois, J M Pierre

    2016-04-01

    The development of an automatic telemedicine system for computer-aided screening and grading of diabetic retinopathy depends on reliable detection of retinal lesions in fundus images. In this paper, a novel method for automatic detection of both microaneurysms and hemorrhages in color fundus images is described and validated. The main contribution is a new set of shape features, called Dynamic Shape Features, that do not require precise segmentation of the regions to be classified. These features represent the evolution of the shape during image flooding and allow to discriminate between lesions and vessel segments. The method is validated per-lesion and per-image using six databases, four of which are publicly available. It proves to be robust with respect to variability in image resolution, quality and acquisition system. On the Retinopathy Online Challenge's database, the method achieves a FROC score of 0.420 which ranks it fourth. On the Messidor database, when detecting images with diabetic retinopathy, the proposed method achieves an area under the ROC curve of 0.899, comparable to the score of human experts, and it outperforms state-of-the-art approaches. PMID:26701180

  3. Dynamics and inherent safety features of small modular high temperature gas-cooled reactors

    SciTech Connect

    Harrington, R.M.; Ball, S.J.; Cleveland, J.C.

    1986-01-01

    Investigations were made at Oak Ridge National Laboratory to characterize the dynamics and inherent safety features of various modular high temperature gas-cooled reactor (HTGR) designs. This work was sponsored by the US Nuclear Regulatory Commission's HTGR Safety Research program. The US Department of Energy (DOE) and the Gas Cooled Reactor Associates (GCRA) have sponsored studies of several modular HTGR concepts, each having it own unique advantageous economic and inherent safety features. The DOE design team has recently choses a 350-MW(t) annular core with prismatic, graphite matrix fuel for its reference plant. The various safety features of this plant and of the pebble-bed core designs similar to those currently being developed and operated in the Federal Republic of Germany (FRG) are described. A varity of postulated accident sequences involving combinations of loss of forced circulation of the helium primary coolant, loss of primary coolant pressurization, and loss of normal and backup heat sinks were studied and are discussed. Results demonstrate that each concept can withstand an uncontrolled heatup accident without reaching excessive peak fuel temperatures. Comparisons of calculated and measured response for a loss of forced circulation test on the FRG reactor, AVR, are also presented. 10 refs.

  4. Distinguishing features of flow in heterogeneous porous media: 4, Is a more general dynamic description required

    SciTech Connect

    Nelson, R.W.

    1990-11-01

    Groundwater theory that applies to only homogeneous systems is often too restricted to adequately solve actual groundwater pollution problems. For adequate solutions, the more general theory for heterogeneous porous systems is needed. However, the present dynamic and kinematic descriptions in heterogeneous materials have evolved largely from the restricted and less general homogeneous theory. These descriptions are inadequate because they fail to account for all the energy dissipation in the system. The basic distinguishing dynamic feature of heterogeneous flow theory from the less general homogeneous-based theory is the macroscopic rotational flow component. Specifically, existence of rotational flow components and their independence from the translational flow components are the necessary and sufficient conditions that completely differentiate between the complex lamellar heterogeneous flow theory and the simpler lamellar flow of homogeneous theory. This paper proposes a more general dynamic form of the flow equation to include the added rotational dissipation that is missing from the present Darcian description of flow in heterogeneous media. 31 refs.

  5. Clinical and pathological features of familial frontotemporal dementia caused by C9ORF72 mutation on chromosome 9p

    PubMed Central

    Hsiung, Ging-Yuek R.; DeJesus-Hernandez, Mariely; Feldman, Howard H.; Sengdy, Pheth; Bouchard-Kerr, Phoenix; Dwosh, Emily; Butler, Rachel; Leung, Bonnie; Fok, Alice; Rutherford, Nicola J.; Baker, Matt; Rademakers, Rosa

    2012-01-01

    Frontotemporal dementia and amyotrophic lateral sclerosis are closely related clinical syndromes with overlapping molecular pathogenesis. Several families have been reported with members affected by frontotemporal dementia, amyotrophic lateral sclerosis or both, which show genetic linkage to a region on chromosome 9p21. Recently, two studies identified the FTD/ALS gene defect on chromosome 9p as an expanded GGGGCC hexanucleotide repeat in a non-coding region of the chromosome 9 open reading frame 72 gene (C9ORF72). In the present study, we provide detailed analysis of the clinical features and neuropathology for 16 unrelated families with frontotemporal dementia caused by the C9ORF72 mutation. All had an autosomal dominant pattern of inheritance. Eight families had a combination of frontotemporal dementia and amyotrophic lateral sclerosis while the other eight had a pure frontotemporal dementia phenotype. Clinical information was available for 30 affected members of the 16 families. There was wide variation in age of onset (mean = 54.3, range = 34–74 years) and disease duration (mean = 5.3, range = 1–16 years). Early diagnoses included behavioural variant frontotemporal dementia (n = 15), progressive non-fluent aphasia (n = 5), amyotrophic lateral sclerosis (n = 9) and progressive non-fluent aphasia–amyotrophic lateral sclerosis (n = 1). Heterogeneity in clinical presentation was also common within families. However, there was a tendency for the phenotypes to converge with disease progression; seven subjects had final clinical diagnoses of both frontotemporal dementia and amyotrophic lateral sclerosis and all of those with an initial progressive non-fluent aphasia diagnosis subsequently developed significant behavioural abnormalities. Twenty-one affected family members came to autopsy and all were found to have transactive response DNA binding protein with Mr 43 kD (TDP-43) pathology in a wide neuroanatomical distribution. All

  6. Clinical and pathological features of familial frontotemporal dementia caused by C9ORF72 mutation on chromosome 9p.

    PubMed

    Hsiung, Ging-Yuek R; DeJesus-Hernandez, Mariely; Feldman, Howard H; Sengdy, Pheth; Bouchard-Kerr, Phoenix; Dwosh, Emily; Butler, Rachel; Leung, Bonnie; Fok, Alice; Rutherford, Nicola J; Baker, Matt; Rademakers, Rosa; Mackenzie, Ian R A

    2012-03-01

    Frontotemporal dementia and amyotrophic lateral sclerosis are closely related clinical syndromes with overlapping molecular pathogenesis. Several families have been reported with members affected by frontotemporal dementia, amyotrophic lateral sclerosis or both, which show genetic linkage to a region on chromosome 9p21. Recently, two studies identified the FTD/ALS gene defect on chromosome 9p as an expanded GGGGCC hexanucleotide repeat in a non-coding region of the chromosome 9 open reading frame 72 gene (C9ORF72). In the present study, we provide detailed analysis of the clinical features and neuropathology for 16 unrelated families with frontotemporal dementia caused by the C9ORF72 mutation. All had an autosomal dominant pattern of inheritance. Eight families had a combination of frontotemporal dementia and amyotrophic lateral sclerosis while the other eight had a pure frontotemporal dementia phenotype. Clinical information was available for 30 affected members of the 16 families. There was wide variation in age of onset (mean = 54.3, range = 34-74 years) and disease duration (mean = 5.3, range = 1-16 years). Early diagnoses included behavioural variant frontotemporal dementia (n = 15), progressive non-fluent aphasia (n = 5), amyotrophic lateral sclerosis (n = 9) and progressive non-fluent aphasia-amyotrophic lateral sclerosis (n = 1). Heterogeneity in clinical presentation was also common within families. However, there was a tendency for the phenotypes to converge with disease progression; seven subjects had final clinical diagnoses of both frontotemporal dementia and amyotrophic lateral sclerosis and all of those with an initial progressive non-fluent aphasia diagnosis subsequently developed significant behavioural abnormalities. Twenty-one affected family members came to autopsy and all were found to have transactive response DNA binding protein with M(r) 43 kD (TDP-43) pathology in a wide neuroanatomical distribution. All had involvement of the extramotor

  7. Design of Unstructured Adaptive (UA) NAS Parallel Benchmark Featuring Irregular, Dynamic Memory Accesses

    NASA Technical Reports Server (NTRS)

    Feng, Hui-Yu; VanderWijngaart, Rob; Biswas, Rupak; Biegel, Bryan (Technical Monitor)

    2001-01-01

    We describe the design of a new method for the measurement of the performance of modern computer systems when solving scientific problems featuring irregular, dynamic memory accesses. The method involves the solution of a stylized heat transfer problem on an unstructured, adaptive grid. A Spectral Element Method (SEM) with an adaptive, nonconforming mesh is selected to discretize the transport equation. The relatively high order of the SEM lowers the fraction of wall clock time spent on inter-processor communication, which eases the load balancing task and allows us to concentrate on the memory accesses. The benchmark is designed to be three-dimensional. Parallelization and load balance issues of a reference implementation will be described in detail in future reports.

  8. Unveiling atomic-scale features of inherent heterogeneity in metallic glass by molecular dynamics simulations

    NASA Astrophysics Data System (ADS)

    Hu, Y. C.; Guan, P. F.; Li, M. Z.; Liu, C. T.; Yang, Y.; Bai, H. Y.; Wang, W. H.

    2016-06-01

    Heterogeneity is commonly believed to be intrinsic to metallic glasses (MGs). Nevertheless, how to distinguish and characterize the heterogeneity at the atomic level is still debated. Based on the extensive molecular dynamics simulations that combine isoconfigurational ensemble and atomic pinning methods, we directly reveal that MG contains flow units and the elastic matrix which can be well distinguished by their distinctive atomic-level responsiveness and mechanical performance. The microscopic features of the flow units, such as the shape, spatial distribution dimensionality, and correlation length, are characterized from atomic position analyses. Furthermore, the correlation between the flow units and the landscape of energy state, free volume, atomic-level stress, and especially the local bond orientational order parameter is discussed.

  9. Young Children’s Affective Responses to Another’s Distress: Dynamic and Physiological Features

    PubMed Central

    Fink, Elian; Heathers, James A. J.; de Rosnay, Marc

    2015-01-01

    Two descriptive studies set out a new approach for exploring the dynamic features of children’s affective responses (sadness and interest-worry) to another’s distress. In two samples (Nstudy1 = 75; Nstudy2 = 114), Kindergarten children were shown a video-vignette depicting another child in distress and the temporal pattern of spontaneous expressions were examined across the unfolding vignette. Results showed, in both study 1 and 2, that sadness and interest-worry had distinct patterns of elicitation across the events of the vignette narrative and there was little co-occurrence of these affects within a given child. Temporal heart rate changes (study 2) were closely aligned to the events of the vignette and, furthermore, affective responses corresponded to distinctive physiological response profiles. The implications of distinct temporal patterns of elicitation for the meaning of sadness and interest-worry are discussed within the framework of emotion regulation and empathy. PMID:25874952

  10. Hand Gesture Spotting Based on 3D Dynamic Features Using Hidden Markov Models

    NASA Astrophysics Data System (ADS)

    Elmezain, Mahmoud; Al-Hamadi, Ayoub; Michaelis, Bernd

    In this paper, we propose an automatic system that handles hand gesture spotting and recognition simultaneously in stereo color image sequences without any time delay based on Hidden Markov Models (HMMs). Color and 3D depth map are used to segment hand regions. The hand trajectory will determine in further step using Mean-shift algorithm and Kalman filter to generate 3D dynamic features. Furthermore, k-means clustering algorithm is employed for the HMMs codewords. To spot meaningful gestures accurately, a non-gesture model is proposed, which provides confidence limit for the calculated likelihood by other gesture models. The confidence measures are used as an adaptive threshold for spotting meaningful gestures. Experimental results show that the proposed system can successfully recognize isolated gestures with 98.33% and meaningful gestures with 94.35% reliability for numbers (0-9).

  11. Young children's affective responses to another's distress: dynamic and physiological features.

    PubMed

    Fink, Elian; Heathers, James A J; de Rosnay, Marc

    2015-01-01

    Two descriptive studies set out a new approach for exploring the dynamic features of children's affective responses (sadness and interest-worry) to another's distress. In two samples (N(study1) = 75; N(study2) = 114), Kindergarten children were shown a video-vignette depicting another child in distress and the temporal pattern of spontaneous expressions were examined across the unfolding vignette. Results showed, in both study 1 and 2, that sadness and interest-worry had distinct patterns of elicitation across the events of the vignette narrative and there was little co-occurrence of these affects within a given child. Temporal heart rate changes (study 2) were closely aligned to the events of the vignette and, furthermore, affective responses corresponded to distinctive physiological response profiles. The implications of distinct temporal patterns of elicitation for the meaning of sadness and interest-worry are discussed within the framework of emotion regulation and empathy. PMID:25874952

  12. Spontaneous Rupture of Pyometra Causing Peritonitis in Elderly Female Diagnosed on Dynamic Transvaginal Ultrasound.

    PubMed

    Malvadkar, Sharad M; Malvadkar, Madhuri S; Domkundwar, Shilpa V; Mohd, Shariq

    2016-01-01

    Pyometra is collection of pus within the uterine cavity and is usually associated with underlying gynaecological malignancy or other benign causes. Spontaneous rupture of pyometra is a rare complication. We report a case of a 65-year-old female who presented with acute abdomen and was diagnosed with a ruptured uterus secondary to pyometra and consequent peritonitis on dynamic transvaginal sonography (TVS) which was later confirmed on contrast enhanced computed tomography (CECT). An emergency laparotomy was performed and about 800 cc of pus was drained from the peritoneal cavity. A rent was found in the anterior uterine wall and hence hysterectomy was performed. Histopathology revealed mixed inflammatory cell infiltrate with no evidence of malignancy. There are only 31 cases of ruptured pyometra reported till date, most of which were definitively diagnosed only on laparotomy. In only two of these cases the preoperative diagnosis was made on CECT. We report this case, as the correct and definitive diagnosis was made preoperatively on dynamic TVS. To our knowledge, this is the first case report revealing spontaneous ruptured pyometra being diagnosed preoperatively on dynamic TVS. This report is aimed at giving emphasis on the use of simple dynamic TVS for accurate diagnosis of rare spontaneous ruptured pyometra causing peritonitis. PMID:26989549

  13. Spontaneous Rupture of Pyometra Causing Peritonitis in Elderly Female Diagnosed on Dynamic Transvaginal Ultrasound

    PubMed Central

    Malvadkar, Sharad M.; Malvadkar, Madhuri S.; Domkundwar, Shilpa V.; Mohd, Shariq

    2016-01-01

    Pyometra is collection of pus within the uterine cavity and is usually associated with underlying gynaecological malignancy or other benign causes. Spontaneous rupture of pyometra is a rare complication. We report a case of a 65-year-old female who presented with acute abdomen and was diagnosed with a ruptured uterus secondary to pyometra and consequent peritonitis on dynamic transvaginal sonography (TVS) which was later confirmed on contrast enhanced computed tomography (CECT). An emergency laparotomy was performed and about 800 cc of pus was drained from the peritoneal cavity. A rent was found in the anterior uterine wall and hence hysterectomy was performed. Histopathology revealed mixed inflammatory cell infiltrate with no evidence of malignancy. There are only 31 cases of ruptured pyometra reported till date, most of which were definitively diagnosed only on laparotomy. In only two of these cases the preoperative diagnosis was made on CECT. We report this case, as the correct and definitive diagnosis was made preoperatively on dynamic TVS. To our knowledge, this is the first case report revealing spontaneous ruptured pyometra being diagnosed preoperatively on dynamic TVS. This report is aimed at giving emphasis on the use of simple dynamic TVS for accurate diagnosis of rare spontaneous ruptured pyometra causing peritonitis. PMID:26989549

  14. Dynamic features of apo and bound HIV-Nef protein reveal the anti-HIV dimerization inhibition mechanism.

    PubMed

    Moonsamy, Suri; Bhakat, Soumendranath; Soliman, Mahmoud E S

    2015-01-01

    The first account on the dynamic features of Nef or negative factor, a small myristoylated protein located in the cytoplasm believes to increase HIV-1 viral titer level, is reported herein. Due to its major role in HIV-1 pathogenicity, Nef protein is considered an emerging target in anti-HIV drug design and discovery process. In this study, comparative long-range all-atom molecular dynamics simulations were employed for apo and bound protein to unveil molecular mechanism of HIV-Nef dimerization and inhibition. Results clearly revealed that B9, a newly discovered Nef inhibitor, binds at the dimeric interface of Nef protein and caused significant separation between orthogonally opposed residues, namely Asp108, Leu112 and Gln104. Large differences in magnitudes were observed in the radius of gyration (∼1.5 Å), per-residue fluctuation (∼2 Å), C-alpha deviations (∼2 Å) which confirm a comparatively more flexible nature of apo conformation due to rapid dimeric association. Compared to the bound conformer, a more globally correlated motion in case of apo structure of HIV-Nef confirms the process of dimeric association. This clearly highlights the process of inhibition as a result of ligand binding. The difference in principal component analysis (PCA) scatter plot and per-residue mobility plot across first two normal modes further justifies the same findings. The in-depth dynamic analyses of Nef protein presented in this report would serve crucial in understanding its function and inhibition mechanisms. Information on inhibitor binding mode would also assist in designing of potential inhibitors against this important HIV target. PMID:26355431

  15. Dynamic impact and pressure analysis of the insensitive munitions container PA103 with modified design features

    SciTech Connect

    Handy, K.D.

    1993-06-01

    This report presents analytical analyses of the insensitive munitions container PA103, with modified design features for a static internal pressure of 500 psi and for a dynamic impact resulting from a 7-ft free fall onto a rigid surface. The modified design features addressed by the analyses were the inclusion of a score pattern on the container cylindrical body and a plastic plate (fuse) sandwiched between metal flanges on the container end. The objectives of both the pressure and impact analyses were to determine if the induced stresses at the score patterns in the cylindrical body of the container were sufficient to induce failure. Analytical responses of the container to the imposed loads were obtained with finite element analysis methodology. The computer codes ABAQUS and VEC/DYNA3D were used to obtain the results. Results of the pressure analysis indicate that failure of the container body would be expected to occur at the score pattern for a static internal pressure of 500 psi. Also, results from three impact orientations for a 7-ft drop indicate that membrane stresses in the vicinity of the score pattern are above critical crack growth stress magnitudes, especially at low ([minus]60[degrees]F) temperatures.

  16. Dynamic impact and pressure analysis of the insensitive munitions container PA103 with modified design features

    SciTech Connect

    Handy, K.D.

    1993-06-01

    This report presents analytical analyses of the insensitive munitions container PA103, with modified design features for a static internal pressure of 500 psi and for a dynamic impact resulting from a 7-ft free fall onto a rigid surface. The modified design features addressed by the analyses were the inclusion of a score pattern on the container cylindrical body and a plastic plate (fuse) sandwiched between metal flanges on the container end. The objectives of both the pressure and impact analyses were to determine if the induced stresses at the score patterns in the cylindrical body of the container were sufficient to induce failure. Analytical responses of the container to the imposed loads were obtained with finite element analysis methodology. The computer codes ABAQUS and VEC/DYNA3D were used to obtain the results. Results of the pressure analysis indicate that failure of the container body would be expected to occur at the score pattern for a static internal pressure of 500 psi. Also, results from three impact orientations for a 7-ft drop indicate that membrane stresses in the vicinity of the score pattern are above critical crack growth stress magnitudes, especially at low ({minus}60{degrees}F) temperatures.

  17. Dynamical and Photometric Simulations of Propeller Features in Saturn's A Ring

    NASA Astrophysics Data System (ADS)

    Halme, Veli-Pekka; Salo, H.; Sremcevic, M.; Albers, N.; Schmidt, J.; Seiss, M.; Spahn, F.

    2010-10-01

    The size distribution of Saturn's ring particles can be generally described by a power-law size distribution from about 1 cm up to a few meters. The existence of larger particles, often called moonlets, in the rings is proven by the effects they have on the surrounding ring material. If the moonlet is not large enough to clear a gap, it will induce a propeller shaped structure, which were first discovered in the observation by the Cassini spacecraft. We have made dynamical and photometric simulations to get contraints on the properties of the propeller features seen in the outer A ring. We also consider the assumption, that some loose material is released from the particles in fast collisions induced by the moonlet. This debris is the reason for the enhanced optical thickness in the propeller features. We show that the debris model is able to explain the phase angle dependent appearance of the observed propellers on both the lit and the unlit side of the rings. This work is supported by the Academy of Finland/Graduate School for Astronomy and Space Physics

  18. Emission features and expansion dynamics of nanosecond laser ablation plumes at different ambient pressures

    SciTech Connect

    Farid, N.; Harilal, S. S. Hassanein, A.; Ding, H.

    2014-01-21

    The influence of ambient pressure on the spectral emission features and expansion dynamics of a plasma plume generated on a metal target has been investigated. The plasma plumes were generated by irradiating Cu targets using 6 ns, 1064 nm pulses from a Q-switched Nd:YAG laser. The emission and expansion dynamics of the plasma plumes were studied by varying air ambient pressure levels ranging from vacuum to atmospheric pressure. The ambient pressure levels were found to affect both the line intensities and broadening along with the signal to background and signal to noise ratios and the optimum pressure conditions for analytical applications were evaluated. The characteristic plume parameters were estimated using emission spectroscopy means and noticed that the excitation temperature peaked ∼300 Torr, while the electron density showed a maximum ∼100 Torr. Fast-gated images showed a complex interaction between the plume and background air leading to changes in the plume geometry with pressure as well as time. Surface morphology of irradiated surface showed that the pressure of the ambient gas affects the laser-target coupling significantly.

  19. Structural and Dynamic Features of F-recruitment Site Driven Substrate Phosphorylation by ERK2.

    PubMed

    Piserchio, Andrea; Ramakrishan, Venkatesh; Wang, Hsin; Kaoud, Tamer S; Arshava, Boris; Dutta, Kaushik; Dalby, Kevin N; Ghose, Ranajeet

    2015-01-01

    The F-recruitment site (FRS) of active ERK2 binds F-site (Phe-x-Phe-Pro) sequences found downstream of the Ser/Thr phospho-acceptor on cellular substrates. Here we apply NMR methods to analyze the interaction between active ERK2 (ppERK2), and a 13-residue F-site-bearing peptide substrate derived from its cellular target, the transcription factor Elk-1. Our results provide detailed insight into previously elusive structural and dynamic features of FRS/F-site interactions and FRS-driven substrate phosphorylation. We show that substrate F-site engagement significantly quenches slow dynamics involving the ppERK2 activation-loop and the FRS. We also demonstrate that the F-site phenylalanines make critical contacts with ppERK2, in contrast to the proline whose cis-trans isomerization has no significant effect on F-site recognition by the kinase FRS. Our results support a mechanism where phosphorylation of the disordered N-terminal phospho-acceptor is facilitated by its increased productive encounters with the ppERK2 active site due to docking of the proximal F-site at the kinase FRS. PMID:26054059

  20. Structural and Dynamic Features of F-recruitment Site Driven Substrate Phosphorylation by ERK2

    PubMed Central

    Piserchio, Andrea; Ramakrishan, Venkatesh; Wang, Hsin; Kaoud, Tamer S.; Arshava, Boris; Dutta, Kaushik; Dalby, Kevin N.; Ghose, Ranajeet

    2015-01-01

    The F-recruitment site (FRS) of active ERK2 binds F-site (Phe-x-Phe-Pro) sequences found downstream of the Ser/Thr phospho-acceptor on cellular substrates. Here we apply NMR methods to analyze the interaction between active ERK2 (ppERK2), and a 13-residue F-site-bearing peptide substrate derived from its cellular target, the transcription factor Elk-1. Our results provide detailed insight into previously elusive structural and dynamic features of FRS/F-site interactions and FRS-driven substrate phosphorylation. We show that substrate F-site engagement significantly quenches slow dynamics involving the ppERK2 activation-loop and the FRS. We also demonstrate that the F-site phenylalanines make critical contacts with ppERK2, in contrast to the proline whose cis-trans isomerization has no significant effect on F-site recognition by the kinase FRS. Our results support a mechanism where phosphorylation of the disordered N-terminal phospho-acceptor is facilitated by its increased productive encounters with the ppERK2 active site due to docking of the proximal F-site at the kinase FRS. PMID:26054059

  1. Integrative “Omics”-Approach Discovers Dynamic and Regulatory Features of Bacterial Stress Responses

    PubMed Central

    Mank, Nils N.; Looso, Mario; Rische, Tom; Förstner, Konrad U.; Krüger, Marcus; Klug, Gabriele

    2013-01-01

    Bacteria constantly face stress conditions and therefore mount specific responses to ensure adaptation and survival. Stress responses were believed to be predominantly regulated at the transcriptional level. In the phototrophic bacterium Rhodobacter sphaeroides the response to singlet oxygen is initiated by alternative sigma factors. Further adaptive mechanisms include post-transcriptional and post-translational events, which have to be considered to gain a deeper understanding of how sophisticated regulation networks operate. To address this issue, we integrated three layers of regulation: (1) total mRNA levels at different time-points revealed dynamics of the transcriptome, (2) mRNAs in polysome fractions reported on translational regulation (translatome), and (3) SILAC-based mass spectrometry was used to quantify protein abundances (proteome). The singlet oxygen stress response exhibited highly dynamic features regarding short-term effects and late adaptation, which could in part be assigned to the sigma factors RpoE and RpoH2 generating distinct expression kinetics of corresponding regulons. The occurrence of polar expression patterns of genes within stress-inducible operons pointed to an alternative of dynamic fine-tuning upon stress. In addition to transcriptional activation, we observed significant induction of genes at the post-transcriptional level (translatome), which identified new putative regulators and assigned genes of quorum sensing to the singlet oxygen stress response. Intriguingly, the SILAC approach explored the stress-dependent decline of photosynthetic proteins, but also identified 19 new open reading frames, which were partly validated by RNA-seq. We propose that comparative approaches as presented here will help to create multi-layered expression maps on the system level (“expressome”). Finally, intense mass spectrometry combined with RNA-seq might be the future tool of choice to re-annotate genomes in various organisms and will help to

  2. Considerations of solar wind dynamics in mapping of Jupiter's auroral features to magnetospheric sources

    NASA Astrophysics Data System (ADS)

    Gyalay, S.; Vogt, M.; Withers, P.

    2015-12-01

    Previous studies have mapped locations from the magnetic equator to the ionosphere in order to understand how auroral features relate to magnetospheric sources. Vogt et al. (2011) in particular mapped equatorial regions to the ionosphere by using a method of flux equivalence—requiring that the magnetic flux in a specified region at the equator is equal to the magnetic flux in the region to which it maps in the ionosphere. This is preferred to methods relying on tracing field lines from global Jovian magnetic field models, which are inaccurate beyond 30 Jupiter radii from the planet. That previous study produced a two-dimensional model—accounting for changes with radial distance and local time—of the normal component of the magnetic field in the equatorial region. However, this two-dimensional fit—which aggregated all equatorial data from Pioneer 10, Pioneer 11, Voyager 1, Voyager 2, Ulysses, and Galileo—did not account for temporal variability resulting from changing solar wind conditions. Building off of that project, this study aims to map the Jovian aurora to the magnetosphere for two separate cases: with a nominal magnetosphere, and with a magnetosphere compressed by high solar wind dynamic pressure. Using the Michigan Solar Wind Model (mSWiM) to predict the solar wind conditions upstream of Jupiter, intervals of high solar wind dynamic pressure were separated from intervals of low solar wind dynamic pressure—thus creating two datasets of magnetometer measurements to be used for two separate 2D fits, and two separate mappings.

  3. Characterizing thermal features from multi-spectral remote sensing data using dynamic calibration procedures

    NASA Astrophysics Data System (ADS)

    Hardy, Colin C.

    A thermal infrared remote sensing project was implemented to develop methods for identifying, classifying, and mapping thermal features. This study is directed at geothermal features, with the expectation that new protocols developed here will apply to the wildland fire thermal environment. Airborne multi-spectral digital imagery was acquired over the geothermally active Norris Basin region of Yellowstone National Park, USA. Two image acquisitions were flown, with one near solar noon and the other at night. The five-band image data included thermal infrared (TIR), near-infrared (NIR), and three visible bandpasses. While focused on TIR, the study relied on the multi-spectral visible and NIR data as well as on an ancillary hyperspectral data set. The raw, five-band data were uncalibrated, requiring implementation of two calibration protocols. First, a vicarious calibration procedure was developed to compute reflectance for the visible and NIR bands using an independently calibrated hyperspectral dataset. Second, a dynamic, in-scene calibration procedure was developed for the thermal sensor that exploited natural, pseudo-invariant thermal reference targets instrumented with kinetic temperature recorders. A suite of thermal attributes was derived, including daytime and nighttime radiant temperatures, a temperature difference (DeltaT), albedo, one minus albedo, and apparent thermal inertia (ATI). The albedo terms were computed using a published weighed-average albedo algorithm based on ratios of the narrowband red and NIR reflectances to total solar irradiance for the respective red and NIR bandpasses. In the absence of verifiable "truth," a step-wise chain of unsupervised classification and multivariate analysis exercises was performed, drawing heavily on "fuzzy truth." A final classification synthesizes a "thermal phenomenology" comprised of four components: spectral, statistical, geographical/contextual, and feature space. In situ measurements paired with image data

  4. The kinetic features of ion dynamics in the closed magnetic configurations.

    NASA Astrophysics Data System (ADS)

    Malykhin, Andrey; Grigorenko, Elena; Malova, Helmi

    2016-04-01

    A lot of spacecraft observations showed that the closed magnetic configurations such as plasmoids and magnetic islands are often observed in the Earth magnetotail. The purpose of our study is to analyze the kinetic features of nonadiabatic ion dynamics in the current sheet (CS) inside a plasmoid and the efficiency of ion acceleration in such configurations. Trajectories of test ions of different masses (H+ i O+) were studied in the prescribed magnetic configuration similar to the one observed by Cluster spacecraft (s/c). The magnetic configuration consists of a single stationary plasmoid in the tail side of a near-Earth magnetic X-line. Everywhere in the system there is the constant and uniform dawn-dusk electric field Ey ~ 0.1 mV/m. Cold ion beams with the characteristics similar to the ones observed in the lobe were launched in the system. In the absence of electromagnetic fluctuations the plasmoid localization in the dawn-dusk direction imposes a limit on the ion energy gain in the course of ion nonadiabatic interaction with the plasmoid's CS (in the region of minimum |B| field). The ion dynamics and energy gain changed dramatically when we introduced the low-frequency electromagnetic fluctuations into the plasmoid. The spectra of the magnetic and electric field fluctuations were similar to the ones observed inside the plasmoids by Cluster spacecraft. Our analysis showed that in the presence of fluctuations the ion dynamics and energy gain are defined by the resonant interaction of ions with the wave harmonics. Ions can gain energy hundred times larger than their energy gain in the system without electromagnetic fluctuations. The inclusion of a guide magnetic field (By) significantly affects the ion dynamics inside the plasmoid. The presence of a guide field generates the "north-south" asymmetry in the ejection of nonadiabatic ions from the CS. The effects of the "north-south" asymmetry in the spatial distribution of the nonadiabatic ions inside the plasmoid on

  5. Nonlinear dynamic behaviors of permanent magnet synchronous motors in electric vehicles caused by unbalanced magnetic pull

    NASA Astrophysics Data System (ADS)

    Xiang, Changle; Liu, Feng; Liu, Hui; Han, Lijin; Zhang, Xun

    2016-06-01

    Unbalanced magnetic pull (UMP) plays a key role in nonlinear dynamic behaviors of permanent magnet synchronous motors (PMSM) in electric vehicles. Based on Jeffcott rotor model, the stiffness characteristics of the rotor system of the PMSM are analyzed and the nonlinear dynamic behaviors influenced by UMP are investigated. In free vibration study, eigenvalue-based stability analysis for multiple equilibrium points is performed which offers an insight in system stiffness. Amplitude modulation effects are discovered of which the mechanism is explained and the period of modulating signal is carried out by phase analysis and averaging method. The analysis indicates that the effects are caused by the interaction of the initial phases of forward and backward whirling motions. In forced vibration study, considering dynamic eccentricity, frequency characteristics revealing softening type are obtained by harmonic balance method, and the stability of periodic solution is investigated by Routh-Hurwitz criterion. The frequency characteristics analysis indicates that the response amplitude is limited in the range between the amplitudes of the two kinds of equilibrium points. In the vicinity of the continuum of equilibrium points, the system hardly provides resistance to bending, and hence external disturbances easily cause loss of stability. It is useful for the design of the PMSM with high stability and low vibration and acoustic noise.

  6. Specific Features of the Nucleation and Growth of Fatigue Cracks in Steel under Cyclic Dynamic Compression

    NASA Astrophysics Data System (ADS)

    Popelyukh, A. I.; Popelyukh, P. A.; Bataev, A. A.; Nikulina, A. A.; Smirnov, A. I.

    2016-03-01

    The processes of the fracture of 40Kh and U8 steels under cyclic dynamic compression are studied. It has been found that the main cause for the fracture of the cyclically compressed specimens is the propagation of cracks due to the effect of residual tensile stresses, which arise near the tips of the cracks at the stage of the unloading of the specimens. The growth rate of a crack has the maximum value at the initial stage of its propagation in the vicinity of the stress concentrator. As the crack propagates deep into the specimen, its growth rate decreases and depends only slightly on the real cross section of the specimen. The model of the process of the fatigue fracture of the steels under dynamic loading by a cyclically varied compressive force is proposed. It has been found that the high fatigue endurance is provided by tempering at 200°C for the 40Kh steel and at 300°C for the U8 steel.

  7. Is the emotion recognition deficit associated with frontotemporal dementia caused by selective inattention to diagnostic facial features?

    PubMed

    Oliver, Lindsay D; Virani, Karim; Finger, Elizabeth C; Mitchell, Derek G V

    2014-07-01

    Frontotemporal dementia (FTD) is a debilitating neurodegenerative disorder characterized by severely impaired social and emotional behaviour, including emotion recognition deficits. Though fear recognition impairments seen in particular neurological and developmental disorders can be ameliorated by reallocating attention to critical facial features, the possibility that similar benefits can be conferred to patients with FTD has yet to be explored. In the current study, we examined the impact of presenting distinct regions of the face (whole face, eyes-only, and eyes-removed) on the ability to recognize expressions of anger, fear, disgust, and happiness in 24 patients with FTD and 24 healthy controls. A recognition deficit was demonstrated across emotions by patients with FTD relative to controls. Crucially, removal of diagnostic facial features resulted in an appropriate decline in performance for both groups; furthermore, patients with FTD demonstrated a lack of disproportionate improvement in emotion recognition accuracy as a result of isolating critical facial features relative to controls. Thus, unlike some neurological and developmental disorders featuring amygdala dysfunction, the emotion recognition deficit observed in FTD is not likely driven by selective inattention to critical facial features. Patients with FTD also mislabelled negative facial expressions as happy more often than controls, providing further evidence for abnormalities in the representation of positive affect in FTD. This work suggests that the emotional expression recognition deficit associated with FTD is unlikely to be rectified by adjusting selective attention to diagnostic features, as has proven useful in other select disorders. PMID:24905284

  8. Causes and consequences of complex population dynamics in an annual plant, Cardamine pensylvanica

    SciTech Connect

    Crone, E.E.

    1995-11-08

    The relative importance of density-dependent and density-independent factors in determining the population dynamics of plants has been widely debated with little resolution. In this thesis, the author explores the effects of density-dependent population regulation on population dynamics in Cardamine pensylvanica, an annual plant. In the first chapter, she shows that experimental populations of C. pensylvanica cycled from high to low density in controlled constant-environment conditions. These cycles could not be explained by external environmental changes or simple models of direct density dependence (N{sub t+1} = f[N{sub t}]), but they could be explained by delayed density dependence (N{sub t+1} = f[N{sub t}, N{sub t+1}]). In the second chapter, she shows that the difference in the stability properties of population growth models with and without delayed density dependence is due to the presence of Hopf as well as slip bifurcations from stable to chaotic population dynamics. She also measures delayed density dependence due to effects of parental density on offspring quality in C. pensylvanica and shows that this is large enough to be the cause of the population dynamics observed in C. pensylvanica. In the third chapter, the author extends her analyses of density-dependent population growth models to include interactions between competing species. In the final chapter, she compares the effects of fixed spatial environmental variation and variation in population size on the evolutionary response of C. pensylvanica populations.

  9. Molecular crowding causes narrowing of population heterogeneity and restricts internal dynamics in a protein

    NASA Astrophysics Data System (ADS)

    Mondal, Samsuzzoha; Kallianpur, Mamata V.; Udgaonkar, Jayant B.; Krishnamoorthy, G.

    2016-03-01

    Macromolecular crowding is a distinguishing property of intracellular media. Knowledge on the structure and dynamics of a protein in a crowded environment is essential for a complete understanding of its function. Reduction in intermolecular space could cause structural and functional alterations. Here, we have studied a model protein barstar to see how polyethylene glycol (PEG)-induced crowding affects its various structural states (native, unfolded and molten-globule-like) with different extents of change in conformational heterogeneity. Intramolecular distances and distance distributions were determined by time-resolved Förster resonance energy transfer from Trp53 to several acceptor sites by analysis of fluorescence decay kinetics using the Maximum Entropy Method. We observed PEG-induced narrowing of population distributions along with shifting of populations towards more compact states. Structural compactness also resulted in the slowing down of internal dynamics of the protein as revealed by fluorescence anisotropy decay kinetics of the fluorophore IAEDANS attached at several sites.

  10. Special features of a substorm during high solar wind dynamic pressure

    SciTech Connect

    Lui, A.T.Y.; Ohtani, S.; Newell, P.T.

    1995-10-01

    A substorm on July 24, 1986, exhibiting a rather unusual auroral morphology is analyzed with data from spacecraft (Viking; DMSP F6 and F7; GOES 5 and 6; three LANL geosynchronous satellites; CCE; and IMP 8). This substorm occurred during high solar wind dynamic pressure (>5 nPa). Several notable features for this substorm are: (1) the substorm onset activity was preceded by prominent auroral activations in the morning sector with spatial separations between adjacent bright regions ranging from {approximately}160 to 640 km, and their intensity was modulated at {approximately}3.2-min intervals; (2) the initial substorm activity was concentrated in the morning sector, followed by a sudden activation in the dusk sector, leaving the midnight sector relatively undisturbed, in sharp contrast to the traditional substorm development; (3) while a substorm injection was observed at a geocentric distance of {approximately}8.4 R{sub E} by CCE in association with the substorm onset, particle injections (detectable with three LANL geosynchronous satellites) and dipolarization signatures (detectable by the two GOES satellites) were not observed until subsequent intensifications; (4) timing subsequent substorm intensifications from injections at the geosynchronous altitude differed from timing intensifications based on Viking auroral images by as much as {approximately}3 min; (5) the polar cap boundary was at a significantly higher latitude than the poleward boundary delineated by detectable auroral luminosity in the auroral oval. Detailed timing analysis suggests the substorm onset to be associated with southward interplanetary magnetic field (IMF), possibly with the crossing of an IMF sector boundary (interplanetary current sheet). The dimming of auroral luminosity in the midnight region was associated with a sudden northward turning of the IMF during high solar wind dynamic pressure condition. 36 refs., 14 figs.

  11. Discriminant analysis of longitudinal cortical thickness changes in Alzheimer's disease using dynamic and network features.

    PubMed

    Li, Yang; Wang, Yaping; Wu, Guorong; Shi, Feng; Zhou, Luping; Lin, Weili; Shen, Dinggang

    2012-02-01

    Neuroimage measures from magnetic resonance (MR) imaging, such as cortical thickness, have been playing an increasingly important role in searching for biomarkers of Alzheimer's disease (AD). Recent studies show that, AD, mild cognitive impairment (MCI) and normal control (NC) can be distinguished with relatively high accuracy using the baseline cortical thickness. With the increasing availability of large longitudinal datasets, it also becomes possible to study the longitudinal changes of cortical thickness and their correlation with the development of pathology in AD. In this study, the longitudinal cortical thickness changes of 152 subjects from 4 clinical groups (AD, NC, Progressive-MCI and Stable-MCI) selected from Alzheimer's Disease Neuroimaging Initiative (ADNI) are measured by our recently developed 4 D (spatial+temporal) thickness measuring algorithm. It is found that the 4 clinical groups demonstrate very similar spatial distribution of grey matter (GM) loss on cortex. To fully utilize the longitudinal information and better discriminate the subjects from 4 groups, especially between Stable-MCI and Progressive-MCI, 3 different categories of features are extracted for each subject, i.e., (1) static cortical thickness measures computed from the baseline and endline, (2) cortex thinning dynamics, such as the thinning speed (mm/year) and the thinning ratio (endline/baseline), and (3) network features computed from the brain network constructed based on the correlation between the longitudinal thickness changes of different regions of interest (ROIs). By combining the complementary information provided by features from the 3 categories, 2 classifiers are trained to diagnose AD and to predict the conversion to AD in MCI subjects, respectively. In the leave-one-out cross-validation, the proposed method can distinguish AD patients from NC at an accuracy of 96.1%, and can detect 81.7% (AUC = 0.875) of the MCI converters 6 months ahead of their conversions to AD

  12. Gilbert-like damping caused by time retardation in atomistic magnetization dynamics

    NASA Astrophysics Data System (ADS)

    Thonig, Danny; Henk, Jürgen; Eriksson, Olle

    2015-09-01

    Gilbert-like damping in magnetization dynamics is commonly attributed to the interplay of the spin, the electron, and the phonon reservoirs. Spatial correlations within the spin reservoir itself, for example magnons, mediate damping as well. We show theoretically that temporal correlations within the spin reservoir cause a similar effect. We investigate the role of time retardation in the atomistic Landau-Lifshitz-Gilbert equation using two different retardation kernels. Although viscous damping is explicitly excluded, we find both analytically and numerically that damping and higher-order effects emerge due to time retardation. Thus, our results establish a mechanism for damping and inertia in magnetic systems.

  13. Brownian dynamics simulation of directional sliding of histone octamers caused by DNA bending

    NASA Astrophysics Data System (ADS)

    Li, Wei; Dou, Shuo-Xing; Xie, Ping; Wang, Peng-Ye

    2006-05-01

    Chromatin-remodeling complexes such as SWI/SNF and RSC of yeast can perturb the structure of nucleosomes in an ATP-dependent manner. Experimental results prove that this chromatin remodeling process involves DNA bending. We simulate the effect of DNA bending, caused by chromatin-remodeling complexes, on directional sliding of histone octamers by Brownian dynamics simulation. The simulation results show that, after a DNA loop being generated at the side of a nucleosome, the histone octamer slides towards this DNA loop until the loop disappears. The DNA loop size is an important factor affecting the process of directional sliding of the histone octamer.

  14. Dynamic forces on agglomerated particles caused by high-intensity ultrasound.

    PubMed

    Knoop, Claas; Fritsching, Udo

    2014-03-01

    In this paper the acoustic forces on particles and agglomerates caused by high-intensity ultrasound in gaseous atmosphere are derived by means of computational fluid dynamics (CFD). Sound induced forces cause an oscillating stress scenario where the primary particles of an agglomerate are alternatingly pressed together and torn apart with the frequency of the applied wave. A comparison of the calculated acoustic forces with respect to the inter particle adhesion forces from Van-der-Waals and liquid bridge interactions reveals that the separation forces may reach the same order of magnitude for 80 μm sized SiO2-particles. Hence, with finite probability acoustically agitated gases may de-agglomerate/disperse solid agglomerate structures. This effect is confirmed by dispersion experiments in an acoustic particle levitation setup. PMID:24152872

  15. Small Deletions of SATB2 Cause Some of the Clinical Features of the 2q33.1 Microdeletion Syndrome

    PubMed Central

    Rosenfeld, Jill A.; Ballif, Blake C.; Lucas, Ann; Spence, Edward J.; Powell, Cynthia; Aylsworth, Arthur S.; Torchia, Beth A.; Shaffer, Lisa G.

    2009-01-01

    Recurrent deletions of 2q32q33 have recently been reported as a new microdeletion syndrome. Clinical features of this syndrome include severe mental retardation, growth retardation, dysmorphic features, thin and sparse hair, feeding difficulties and cleft or high palate. The commonly deleted region contains at least seven genes. Haploinsufficiency of one of these genes, SATB2, a DNA-binding protein that regulates gene expression, has been implicated as causative in the cleft or high palate of individuals with 2q32q33 microdeletion syndrome. In this study we describe three individuals with smaller microdeletions of this region, within 2q33.1. The deletions ranged in size from 173.1 kb to 185.2 kb and spanned part of SATB2. Review of clinical records showed similar clinical features among these individuals, including severe developmental delay and tooth abnormalities. Two of the individuals had behavioral problems. Only one of the subjects presented here had a cleft palate, suggesting reduced penetrance for this feature. Our results suggest that deletion of SATB2 is responsible for several of the clinical features associated with 2q32q33 microdeletion syndrome. PMID:19668335

  16. Dynamic features of a laser-induced cavitation bubble near a solid boundary.

    PubMed

    Yang, Yuan Xiang; Wang, Qian Xi; Keat, T S

    2013-07-01

    This paper deals with detailed features of bubble dynamics near a solid boundary. The cavitation bubble was created by using a Q-switched Nd: YAG laser pulse and observed using a high-speed camera (up to 100,000 frames per second). A hydrophone system was employed to monitor the acoustic signals generated by the transient pressure impulses and estimate the bubble oscillation periods. Experimental observations were carried out for bubbles with various maximum expanded radius Rmax (between 1.0mm and 1.6mm) and stand-off distances, ds (defined as the distance between the solid boundary and the bubble center at inception) of 0.4≤γ≤3.0, and γ=ds/Rmax. The existence of a solid boundary created asymmetry in the flow field and forced the bubble to collapse non-spherically, which finally brought forth the jet impact phenomenon. The dimensionless first and second oscillation periods were dependent on γ. A series of expansion and collapse of the bubble with cascading loss of energy were observed after the bubble had been generated. This study revealed that most bubbles lost about two-thirds of the total energy from the first maximum expansion to the second maximum expansion. PMID:23411165

  17. High borides: determining the features and details of lattice dynamics from neutron spectroscopy

    NASA Astrophysics Data System (ADS)

    Alekseev, P. A.

    2015-04-01

    We review wide-ranging research that combines inelastic neutron scattering spectroscopy with phenomenological and ab initio calculations to study the lattice dynamics and specifics of the electron-phonon interaction in three-dimensional boron cluster network systems M B_6 and M B12 ( M= {La}, {Sm}, and {Yb}, {Lu}, {Zr}). A close similarity is found between the atomic vibration spectra of these systems, which is fundamentally due to a strong hierarchy of interatomic interaction in these systems and which manifests itself both in the shape of the low-energy phonon dispersion and in the position of the high-energy edge of the spectrum. Manifestations of strong electron-phonon interactions in the lattice vibration spectra of borides are studied in detail and their relation to the nature and features of the valence-unstable state of rare-earth ions is examined. Resonance nonadiabaticity and magnetovibration interaction effects in spin- and valence-fluctuating systems are given special attention.

  18. Catchment features controlling nitrogen dynamics in running waters above the tree line (central Italian Alps)

    NASA Astrophysics Data System (ADS)

    Balestrini, R.; Arese, C.; Freppaz, M.; Buffagni, A.

    2013-03-01

    The study of nitrogen cycling in mountain areas has a long tradition, as it was applied to better understand and describe ecosystem functioning, as well as to quantify long-distance effects of human activities on remote environments. Nonetheless, very few studies, especially in Europe, have considered catchment features controlling nitrogen dynamics above the tree line with focus on running waters. In this study, relationships between some water chemistry descriptors - including nitrogen species and dissolved organic carbon (DOC) - and catchment characteristics were evaluated for a range of sites located above the tree line (1950-2650 m a.s.l.) at Val Masino, in the central Italian Alps. Land cover categories as well as elevation and slope were assessed at each site. Water samples were collected during the 2007 and 2008 snow free periods, with a nearly monthly frequency. In contrast to dissolved organic nitrogen, nitrate concentrations in running waters showed a spatial pattern strictly connected to the fractional extension of tundra and talus in each basin. Exponential models significantly described the relationships between maximum NO3 and the fraction of vegetated soil cover (negative relation) and talus (positive relation), explaining almost 90% of nitrate variation in running waters. Similarly to nitrate but with an opposite behavior, DOC was positively correlated with vegetated soil cover and negatively correlated with talus. Therefore, land cover can be considered one of the most important factors affecting water quality in high-elevation catchments with contrasting effects on N and C pools.

  19. Long-term disease dynamics in lakes: causes and consequences of chytrid infections in Daphnia populations.

    PubMed

    Johnson, Pieter T J; Ives, Anthony R; Lathrop, Richard C; Carpenter, Stephen R

    2009-01-01

    Understanding the drivers and consequences of disease epidemics is an important frontier in ecology. However, long-term data on hosts, their parasites, and the corresponding environmental conditions necessary to explore these interactions are often unavailable. We examined the dynamics of Daphnia pulicaria, a keystone zooplankter in lake ecosystems, to explore the long-term causes and consequences of infection by a chytridiomycete parasitoid (Polycaryum laeve). After quantifying host-pathogen dynamics from vouchered samples collected over 15 years, we used autoregressive models to evaluate (1) hypothesized drivers of infection, including host density, water temperature, dissolved oxygen, host-food availability, and lake mixing; and (2) the effects of epidemics on host populations. Infection was present in most years but varied widely in prevalence, from < 1% to 34%, with seasonal peaks in early spring and late fall. Within years, lake stratification strongly inhibited P. laeve transmission, such that epidemics occurred primarily during periods of water mixing. Development of the thermocline likely reduced transmission by spatially separating susceptible hosts from infectious zoospores. Among years, ice duration and cumulative snowfall correlated negatively with infection prevalence, likely because of reductions in spring phytoplankton and D. pulicaria density in years with extended winters. Epidemics also influenced dynamics of the host population. Infected D. pulicaria rarely (< 1%) contained eggs, and P. laeve prevalence was positively correlated with sexual reproduction in D. pulicaria. Analyses of D. pulicaria density-dependent population dynamics predicted that, in the absence of P. laeve infection, host abundance would be 11-50% higher than what was observed. By underscoring the importance of complex physical processes in controlling host-parasite interactions and of epidemic disease in influencing host populations, our results highlight the value of long

  20. Experimental investigation of door dynamic opening caused by impinging shock wave

    NASA Astrophysics Data System (ADS)

    Biamino, L.; Jourdan, G.; Mariani, C.; Igra, O.; Massol, A.; Houas, L.

    2011-02-01

    To prevent damage caused by accidental overpressure inside a closed duct (e.g. jet engine) safety valves are introduced. The present study experimentally investigates the dynamic opening of such valves by employing a door at the end of a shock tube driven section. The door is hung on an axis and is free to rotate, thereby opening the tube. The evolved flow and wave pattern due to a collision of an incident shock wave with the door, causing the door opening, is studied by employing a high speed schlieren system and recording pressures at different places inside the tube as well as on the rotating door. Analyzing this data sheds light on the air flow evolution and the behavior of the opening door. In the present work, emphasis is given to understanding the complex, unsteady flow developed behind the transmitted shock wave as it diffracts over the opening door. It is shown that both the door inertia and the shock wave strength influence the opening dynamic evolution, but not in the proportions that might be expected.

  1. Through enhanced tree dynamics carbon dioxide enrichment may cause tropical forests to lose carbon.

    PubMed Central

    Körner, Christian

    2004-01-01

    The fixation and storage of C by tropical forests, which contain close to half of the globe's biomass C, may be affected by elevated atmospheric CO2 concentration. Classical theoretical approaches assume a uniform stimulation of photosynthesis and growth across taxa. Direct assessments of the C balance either by flux studies or by repeated forest inventories also suggest a current net uptake, although magnitudes sometimes exceed those missing required to balance the global C cycle. Reasons for such discrepancies may lie in the nature of forest dynamics and in differential responses of taxa or plant functional types. In this contribution I argue that CO2 enrichment may cause forests to become more dynamic and that faster tree turnover may in fact convert a stimulatory effect of elevated CO2 on photosynthesis and growth into a long-term net biomass C loss by favouring shorter-lived trees of lower wood density. At the least, this is a scenario that deserves inclusion into long-term projections of the C relations of tropical forests. Species and plant functional type specific responses ('biodiversity effects') and forest dynamics need to be accounted for in projections of future C storage and cycling in tropical forests. PMID:15212098

  2. A three-dimensional porous metal-organic framework constructed from two-dimensional sheets via interdigitation exhibiting dynamic features.

    SciTech Connect

    Ma, S.; Sun, D.; Forster, P. M.; Yuan, D.; Zhuang, W.; Chen, Y. S.; Parise, J. B.; Zhou, H. C.

    2009-04-23

    A three-dimensional porous metal-organic framework (PCN-18) was constructed through interdigitating two-dimensional grid sheets composed of 4,4{prime}-(anthracene-9,10-diyl)dibenzoate and copper paddlewheel secondary building units, and its dynamic features were evidenced by gas sorption isotherms.

  3. An Analysis of the Structure and Dynamics of Inner Core Precipitation Features in a Tropical Cyclone

    NASA Astrophysics Data System (ADS)

    Didlake, Anthony C., Jr.

    Airborne Doppler radar observations of the stationary rainband complex and secondary eyewall in Hurricane Rita (2005) were analyzed to better understand the inner-core dynamics of tropical cyclones. In the upwind end of the rainband complex, convective cells displayed kinematic structures that varied with radius. Cells at smaller radii contained a low-level tangential jet constrained in altitude largely by tangential acceleration due to angular momentum conservation, while cells at larger radii contained a low-level and/or midlevel jet determined jointly by angular momentum conservation and vertical advection. These variations are attributable to vortex-scale dynamics in which convective buoyancy (associated with vertical advection) and vertical shear of the radial wind (associated with angular momentum conservation) change with radius. With jets constrained to low altitudes, inner cells are more likely to increase low-level convergence and amplify convection, possibly influencing the formation of a secondary eyewall. In the downwind end of the rainband complex, collapsing convective cells formed a mesoscale stratiform rainband that contained rising radial outflow within the stratiform cloud layer. Below the cloud layer, descending radial inflow was driven by horizontal buoyancy gradients, and thus horizontal vorticity generation, introduced by regions of sublimational and melting cooling. This inflow advected higher angular momentum inward, which resulted in the development of a midlevel tangential jet and broadening of the tangential wind field. This circulation may have also contributed to ventilation of the eyewall as inflow of low-entropy air continued past the rainband in both the boundary layer and midlevels. The stationary rainband complex soon evolved into a secondary eyewall, consisting of a ring of heavy precipitation outside the pre-existing eyewall. Enhanced radial outflow was located just above the boundary layer which modified the deeper overturning

  4. Blast exposure causes dynamic microglial/macrophage responses and microdomains of brain microvessel dysfunction.

    PubMed

    Huber, B R; Meabon, J S; Hoffer, Z S; Zhang, J; Hoekstra, J G; Pagulayan, K F; McMillan, P J; Mayer, C L; Banks, W A; Kraemer, B C; Raskind, M A; McGavern, D B; Peskind, E R; Cook, D G

    2016-04-01

    Exposure to blast overpressure (BOP) is associated with behavioral, cognitive, and neuroimaging abnormalities. We investigated the dynamic responses of cortical vasculature and its relation to microglia/macrophage activation in mice using intravital two-photon microscopy following mild blast exposure. We found that blast caused vascular dysfunction evidenced by microdomains of aberrant vascular permeability. Microglial/macrophage activation was specifically associated with these restricted microdomains, as evidenced by rapid microglial process retraction, increased ameboid morphology, and escape of blood-borne Q-dot tracers that were internalized in microglial/macrophage cell bodies and phagosome-like compartments. Microdomains of cortical vascular disruption and microglial/macrophage activation were also associated with aberrant tight junction morphology that was more prominent after repetitive (3×) blast exposure. Repetitive, but not single, BOPs also caused TNFα elevation two weeks post-blast. In addition, following a single BOP we found that aberrantly phosphorylated tau rapidly accumulated in perivascular domains, but cleared within four hours, suggesting it was removed from the perivascular area, degraded, and/or dephosphorylated. Taken together these findings argue that mild blast exposure causes an evolving CNS insult that is initiated by discrete disturbances of vascular function, thereby setting the stage for more protracted and more widespread neuroinflammatory responses. PMID:26777891

  5. Progeroid laminopathy with restrictive dermopathy-like features caused by an isodisomic LMNA mutation p.R435C

    PubMed Central

    Camozzi, Daria; Mattioli, Elisabetta; Pfaeffle, Roland; Siekmeyer, Manuela; Hirsch, Wolfgang; Horn, Lars Christian; Paasch, Uwe; Mitter, Diana; Lattanzi, Giovanna; Wehnert, Manfred; Kiess, Wieland

    2013-01-01

    The clinical course of a female patient affected by a progeroid syndrome with Restrictive Dermopathy (RD)-like features was followed up. Besides missing hairiness, stagnating weight and growth, RD-like features including progressive skin swelling and solidification, acrocontractures, osteolysis and muscular hypotension were observed until the patient died at the age of 11 months. A homozygous LMNA mutation c.1303C>T (p.R435C) was found by Sanger sequencing. Haplotyping revealed a partial uniparental disomy of chromosome 1 (1q21.3 to 1q23.1) including the LMNA gene. In contrast to reported RD patients with LMNA mutations, LMNA p.R435C is not located at the cleavage site necessary for processing of prelamin A by ZMPSTE24 and leads to a distinct phenotype combining clinical features of Restrictive Dermopathy, Mandibuloacral Dysplasia and Hutchinson-Gilford Progeria. Functionally, LMNA p.R435C is associated with increasing DNA double strand breaks and decreased recruitment of P53 binding protein 1 (53BP1) to DNA-damage sites indicating delayed DNA repair. The follow-up of the complete clinical course in the patient combined with functional studies showed for the first time that a progressive loss of lamin A rather than abnormal accumulation of prelamin A species could be a pathophysiological mechanism in progeroid laminopathies, which leads to DNA repair deficiency accompanied by advancing tissue degeneration. PMID:23804595

  6. The hydraulic separator Multidune: preliminary tests on fluid-dynamic features and plastic separation feasibility.

    PubMed

    De Sena, Giulia; Nardi, Camillo; Cenedese, Antonio; La Marca, Floriana; Massacci, Paolo; Moroni, Monica

    2008-01-01

    Recycling of plastic materials is a rapidly developing discipline because of environmental awareness, the need to conserve materials and energy, and the growing demand to increase the production economy. The main problem in plastics recovery and recycling is related to the variety of plastic wastes, even if selective collection occurs. Therefore, plastic materials can be recycled either as mixtures or as single types, separating the different typologies by their physical (size, specific mass, etc.) and/or chemical properties. However, separation of plastics in single typologies by traditional processes and devices is difficult due to their typical low variability in properties. This paper presents a new research development for recycling industry: the Multidune separator. This is a device constructed from a sequence of parallel semi-cylindrical tubes of transparent plastic welded together in a plane. The lower half is shifted laterally and then fixed relative to the upper half. Flow is then induced in the lateral direction normal to the axis of the tubes, creating a main flow channel and two recirculation zones. This apparatus creates a differential transport of particles of low specific mass, near to 1g/cm3, allowing their separation. The flow field in the Multidune separator is studied via Particle Tracking Velocimetry (PTV). Eulerian analysis of the data is performed to gather information about the fluid-dynamics features established by different hydraulic heads at the inlet of the Multidune. Preliminary tests on monomaterial samples have been performed, varying several operative parameters to determine the best set of values. Therefore, separation tests have been executed on composite samples, obtaining satisfactory results in terms of plastic separation feasibility. PMID:17935965

  7. The Relation between Solar Eruption Topologies and Observed Flare Features. II. Dynamical Evolution

    NASA Astrophysics Data System (ADS)

    Savcheva, A.; Pariat, E.; McKillop, S.; McCauley, P.; Hanson, E.; Su, Y.; DeLuca, E. E.

    2016-01-01

    A long-established goal of solar physics is to build understanding of solar eruptions and develop flare and coronal mass ejection (CME) forecasting models. In this paper, we continue our investigation of nonlinear forces free field (NLFFF) models by comparing topological properties of the solutions to the evolution of the flare ribbons. In particular, we show that data-constrained NLFFF models of three erupting sigmoid regions (SOL2010-04-08, SOL2010-08-07, and SOL2012-05-12) built to reproduce the active region magnetic field in the pre-flare state can be rendered unstable and the subsequent sequence of unstable solutions produces quasi-separatrix layers that match the flare ribbon evolution as observed by SDO/AIA. We begin with a best-fit equilibrium model for the pre-flare active region. We then add axial flux to the flux rope in the model to move it across the stability boundary. At this point, the magnetofrictional code no longer converges to an equilibrium solution. The flux rope rises as the solutions are iterated. We interpret the sequence of magnetofrictional steps as an evolution of the active region as the flare/CME begins. The magnetic field solutions at different steps are compared with the flare ribbons. The results are fully consistent with the three-dimensional extension of the standard flare/CME model. Our ability to capture essential topological features of flaring active regions with a non-dynamic magnetofrictional code strongly suggests that the pre-flare, large-scale topological structures are preserved as the flux rope becomes unstable and lifts off.

  8. Dynamics of Flow Over A Low Hill Caused By Change In Surface Heat Flux

    NASA Astrophysics Data System (ADS)

    Owinoh, A. Z.; Hunt, J. C. R.; Orr, A.; Klein, R.

    Our understanding of flow over complex terrain has been shaped partially by the theo- retical work of Hunt and colleagues (e.g. Hunt et al., 1988) which is based on the tech- niques of asymptotic matching. The boundary layer is divided into three sub-layers, each with essentially different flow dynamics. The dynamics of the lowest layer (the inner layer) are modified by turbulence generated by surface properties. In the middle layer, the flow is inviscid but rotational. In the outer layer, turbulent friction is rela- tively unimportant and one can treat the flow as essentially inviscid. In this talk, we present the dynamics of the inner region of flow over low hill, on whose surface there is an abrupt (t > 0), but uniform, change in heat flux. The leading order perturbation to the basic flow equations are solved analytically. The solutions show how an initially neutral turbulent flow (Lmo = +) responds to change in heat flux by making a tran- sition (in time) to stable (Lmo > 0) and unstable flows (Lmo < 0), where Lmo is the Monin-Obukhov length. In doing so |Lmo| decreases to the length of the inner layer. Buoyancy forces have large effect on the down slope flow (e.g. recirculating wake and increased vertical shear). Features of the solutions are compared with Scorer's (1955) observations and with experimental results obtained from two numerical weather fore- cast models, namely, UK Met. Office Unified Model and the German Weather Service (DWD) Lokall-Modell. Hunt, J. C. R., Leibovich, S. &Richards K. J., 1988, `Turbulent shear flow over low hills'. Q. J. R. Meteorol. Soc, 114, 1435-1470. Scorer, R. S. 1955, `Theory of airflow over mountains: IV - Separation of flow from the surface', Q. J. R. Meteorol. Soc., 81, 340-350.

  9. An investigation into potential causes of the anomalistic feature observed by the Rosetta Alice spectrograph around 67P/Churyumov-Gerasimenko

    NASA Astrophysics Data System (ADS)

    Noonan, John; Schindhelm, Eric; Parker, Joel Wm.; Steffl, Andrew; Davis, Michael; Stern, S. Alan; Levin, Zuni; Kempf, Sascha; Horanyi, Mihaly

    2016-08-01

    The Alice far-ultraviolet spectrograph in operation around the comet 67P/Churyumov-Gerasimenko on the Rosetta spacecraft experiences an anomalistic feature (AF) that is ubiquitous at comet separations less than 450 km. This feature is highly temporally variable and displays no relation to any studied parameters with the exception of comet separation. This paper tests several possible causes with simulations and finds that positive ions produce a partial explanation for the anomaly, but still finds no definitive source of the AF.

  10. Dynamic left ventricular outflow tract obstruction: underestimated cause of hypotension and hemodynamic instability

    PubMed Central

    2014-01-01

    Left ventricular outflow tract obstruction, which is typically associated with hypertrophic cardiomyopathy, is the third most frequent cause of unexplained hypotension. This underestimated problem may temporarily accompany various diseases (it is found in even <1% of patients with no tangible cardiac disease) and clinical situations (hypovolemia, general anesthesia). It is currently assumed that left ventricular outflow tract obstruction is a dynamic phenomenon, the occurrence of which requires the coexistence of predisposing anatomic factors and a physiological condition that induces it. The diagnosis of left ventricular outflow tract obstruction should entail immediate implementation of the therapy to eliminate the factors that can potentially intensify the obstruction. Echocardiography is the basic modality in the diagnosis and treatment of left ventricular outflow tract obstruction. This paper presents four patients in whom the immediate implementation of bedside echocardiography enabled a rapid diagnosis of left ventricular outflow tract obstruction and implementation of proper treatment. PMID:26674265

  11. Nonlinear climate sensitivity caused by the ocean dynamics: implications for the Early Anthropogenic Hypothesis

    NASA Astrophysics Data System (ADS)

    He, F.; Vavrus, S. J.; Kutzbach, J. E.; Ruddiman, W. F.

    2012-12-01

    The climate sensitivity, i.e., the increase of global mean temperature with a doubling of atmospheric CO2, is almost always estimated using atmosphere models with a slab ocean, due to the computational challenges from equilibrium runs of coupled atmosphere-ocean models. The use of slab-ocean runs to approximate full-depth ocean runs requires that the slab-ocean runs, which lack ocean dynamics, can reproduce the sea ice changes from full-depth ocean runs. This might not be true, as numerous modelling studies show that ocean dynamics play an important role in rapid reductions of Arctic sea ice. In this study, we aim to quantify the role of ocean dynamics in climate sensitivity in CCSM4. Two sets of the CCSM4 experiments were conducted in either fully-coupled or slab-ocean configuration with greenhouse gas concentrations from the present-day (PD, CO2=355 ppm), pre-industrial (PI, CO2=280 ppm) and hypothetical non-anthropogenic (NA, CO2=245 ppm) pre-industrial scenario from Ruddiman's Early Anthropogenic Hypothesis. Our results show that the sensitivities of Northern Hemisphere permanent snow, Northern Hemisphere sea ice and global mean temperature are essentially linear in the slab-ocean runs, but highly non-linear in the fully-coupled simulations, with larger sensitivity during the transition of colder climates between PI and NA. The comparison between the fully-coupled and the slab-ocean simulations shows that ocean dynamics causes significantly larger increase of North Atlantic sea ice during the PI/NA transition than the PD/PI transition, suggesting a threshold might have been crossed during the PI/NA transition. Our results suggest that slab-ocean runs might underestimate the climate sensitivity due to the lack of ocean dynamics. The implication of this study is that a small increase of greenhouse gas concentration from the early agriculture several thousand years ago might have prevented the Earth from crossing this threshold that leads to glacial inceptions.

  12. Novel features of end-gas aotoignition revealed by computational fluid dynamics

    SciTech Connect

    Griffiths, J.F.; Rose, D.J. ); Schreiber, M.; Meyer, J.; Knoche, K.F. )

    1992-11-01

    Autoignition of the end-gas in the combustion chamber is believed to be a primary cause of knock in spark ignition engines. Fundamental studies of the autoignition of hydrocarbon + air mixtures has been performed successfully in rapid compression machines. There has also been considerable progress towards the numerical modeling of these phenomena, but applications to combustion in a rapid compression machine have been based only on a spatially uniform well-mixed condition. The authors report in this paper the implementation of a fluid dynamics code in conjunction with the Shell generalized (or reduced) kinetic model, which represents the exothermic oxidation of the alkane components of gasoline, to predict the development of autoignition in the combustion chamber. The numerical simulations reported in this paper were matched to the performance of the rapid compression apparatus in use at Leeds. In this system, combustion occurred in a cylindrical chamber, the flat, end faces of which were the piston crown and cylinder head. The reactants were compressed by a piston, which was then brought to rest at the end of its stroke. The geometric configuration of the combustion chamber of the rapid compression machine is fully axisymmetric. This permitted a two-dimensional treatment of spatial conditions on a plane representing piston displacement and half radius. Reactive gas flows were simulated on a 14 [times] 50 mesh at the start of compression, which was reduced to 14 [times] 10 cells as the piston reached top-dead-center. The resolution within the vicinity of the cylinder wall was enhanced by a nonequidistant grid structure.

  13. Assessing uncertainties in a second-generation dynamic vegetation model caused by ecological scale limitations.

    PubMed

    Fisher, Rosie; McDowell, Nate; Purves, Drew; Moorcroft, Paul; Sitch, Stephen; Cox, Peter; Huntingford, Chris; Meir, Patrick; Woodward, F Ian

    2010-08-01

    *Second-generation Dynamic Global Vegetation Models (DGVMs) have recently been developed that explicitly represent the ecological dynamics of disturbance, vertical competition for light, and succession. Here, we introduce a modified second-generation DGVM and examine how the representation of demographic processes operating at two-dimensional spatial scales not represented by these models can influence predicted community structure, and responses of ecosystems to climate change. *The key demographic processes we investigated were seed advection, seed mixing, sapling survival, competitive exclusion and plant mortality. We varied these parameters in the context of a simulated Amazon rainforest ecosystem containing seven plant functional types (PFTs) that varied along a trade-off surface between growth and the risk of starvation induced mortality. *Varying the five unconstrained parameters generated community structures ranging from monocultures to equal co-dominance of the seven PFTs. When exposed to a climate change scenario, the competing impacts of CO(2) fertilization and increasing plant mortality caused ecosystem biomass to diverge substantially between simulations, with mid-21st century biomass predictions ranging from 1.5 to 27.0 kg C m(-2). *Filtering the results using contemporary observation ranges of biomass, leaf area index (LAI), gross primary productivity (GPP) and net primary productivity (NPP) did not substantially constrain the potential outcomes. We conclude that demographic processes represent a large source of uncertainty in DGVM predictions. PMID:20618912

  14. Climate change causing phase transitions of walleye pollock (Theragra chalcogramma) recruitment dynamics.

    PubMed

    Ciannelli, Lorenzo; Bailey, Kevin M; Chan, Kung-Sik; Belgrano, Andrea; Stenseth, Nils Chr

    2005-08-22

    In 1976 the North Pacific climate shifted, resulting in an average increase of the water temperature. In the Gulf of Alaska the climate shift was followed (i.e. early 1980s) by a gradual but dramatic increase in the abundance of groundfish species that typically prey on pre-recruitment stages of walleye pollock. In the present study we used a previously parameterized model to investigate the effect of these climate and biological changes on the recruitment dynamics of walleye pollock in the Gulf of Alaska. Simulations covered the 1970-2000 time frame and emphasized the medium-to-long temporal scale (i.e. about 5-10 years) of environmental variability. Results showed that during periods characterized by high sea surface temperature and high predation on juvenile pollock stages, recruitment variability and magnitude were below average, and recruitment control was delayed to stages older than the 0-group. Opposite dynamics (i.e. high abundance and variability, and early recruitment control) occurred during periods characterized by low temperature and predation. These results are in general agreement with empirical observations, and allowed us to formulate causal explanations for their occurrence. We interpreted the delay of recruitment control and the reduction of variability as an effect of increased constraint on the abundance of post age-0 stages, in turn imposed by high density dependence and predation mortality. On the other hand, low density-dependence and predation favoured post age-0 survival, and allowed for an unconstrained link between larval and recruitment abundance. Our findings demonstrate that the dominant mechanisms of pollock survival change over contrasting climate regimes. Such changes may in turn cause a phase transition of recruitment dynamics with profound implications for the management of the entire stock. PMID:16087430

  15. Structural features of interfacial tyrosine residue in ROBO1 fibronectin domain-antibody complex: Crystallographic, thermodynamic, and molecular dynamic analyses

    PubMed Central

    Nakayama, Taisuke; Mizohata, Eiichi; Yamashita, Takefumi; Nagatoishi, Satoru; Nakakido, Makoto; Iwanari, Hiroko; Mochizuki, Yasuhiro; Kado, Yuji; Yokota, Yuki; Satoh, Reiko; Tsumoto, Kouhei; Fujitani, Hideaki; Kodama, Tatsuhiko; Hamakubo, Takao; Inoue, Tsuyoshi

    2015-01-01

    ROBO1, fibronectin Type-III domain (Fn)-containing protein, is a novel immunotherapeutic target for hepatocellular carcinoma in humans. The crystal structure of the antigen-binding fragment (Fab) of B2212A, the monoclonal antibody against the third Fn domain (Fn3) of ROBO1, was determined in pursuit of antibody drug for hepatocellular carcinoma. This effort was conducted in the presence or absence of the antigen, with the chemical features being investigated by determining the affinity of the antibody using molecular dynamics (MD) and thermodynamics. The structural comparison of B2212A Fab between the complex and the free form revealed that the interfacial TyrL50 (superscripts L, H, and F stand for the residues in the light chain, heavy chain, and Fn3, respectively) played important roles in Fn3 recognition. That is, the aromatic ring of TyrL50 pivoted toward PheF68, forming a CH/π interaction and a new hydrogen bond with the carbonyl O atom of PheF68. MD simulations predicted that the TyrL50-PheF68 interaction almost entirely dominated Fab-Fn3 binding, and Ala-substitution of TyrL50 led to a reduced binding of the resultant complex. On the contrary, isothermal titration calorimetry experiments underscored that Ala-substitution of TyrL50 caused an increase of the binding enthalpy between B2212A and Fn3, but importantly, it induced an increase of the binding entropy, resulting in a suppression of loss in the Gibbs free energy in total. These results suggest that mutation analysis considering the binding entropy as well as the binding enthalpy will aid in the development of novel antibody drugs for hepatocellular carcinoma. PMID:25492858

  16. Intraseasonal variability of organized convective systems in the Central Andes: Relationship to Regional Dynamical Features

    NASA Astrophysics Data System (ADS)

    Mohr, K. I.; Slayback, D. A.; Nicholls, S.; Yager, K.

    2013-12-01

    The Andes extend from the west coast of Colombia (10N) to the southern tip of Chile (53S). In southern Peru and Bolivia, the Central Andes is split into separate eastern and western cordilleras, with a high plateau (≥ 3000 m), the Altiplano, between them. Because 90% of the Earth's tropical mountain glaciers are located in the Central Andes, our study focuses on this region, defining its zonal extent as 7S-21S and the meridional extent as the terrain 1000 m and greater. Although intense convection occurs during the wet season in the Altiplano, it is not included in the lists of regions with frequent or the most intense convection. The scarcity of in-situ observations with sufficient density and temporal resolution to resolve individual storms or even mesoscale-organized cloud systems and documented biases in microwave-based rainfall products in poorly gauged mountainous regions have impeded the development of an extensive literature on convection and convective systems in this region. With the tropical glaciers receding at unprecedented rates, leaving seasonal precipitation as an increasingly important input to the water balance in alpine valley ecosystems and streams, understanding the nature and characteristics of the seasonal precipitation becomes increasingly important for the rural economies in this region. Previous work in analyzing precipitation in the Central Andes has emphasized interannual variability with respect to ENSO, this is the first study to focus on shorter scale variability with respect to organized convection. The present study took advantage of the University of Utah's Precipitation Features database compiled from 14 years of TRMM observations (1998-2012), supplemented by field observations of rainfall and streamflow, historical gauge data, and long-term WRF-simulations, to analyze the intraseasonal variability of precipitating systems and their relationship regional dynamical features such as the Bolivian High. Through time series and

  17. The dynamics of spreading bacterial diseases and ilnesses caused by helminthosis in Adjara Autonomous Republic 2011.

    PubMed

    Lomtatidze, N; Chachnelidze, R; Chkaidze, M

    2013-01-01

    According to the data of past few years it has been determined that the general incidence and the prevalence of the bacterial and helminthosis diseases have increased. Epidemic Supervision has registered a slight increase of such diseases in data of 2011. Taking into consideration this fact, this research is quite important for the region of Adjara. The aim of our research is to study the dynamics of spreading some bacterial and helminthosis diseases in Adjara Autonomous Republic. In particular, the diseases caused by different bacterias of leptospira family - leptospirosis and illnesses caused by helminthosis - ascariasis, enterobiasis and trichocephalosis. according to the reseaches held it has been determined that there have been several cases of leptospirosis registered in Adjara. Specifically, 10 cases in 2008, 6 in 2009, 30 in 2010 and 31 cases in 2011 out of which 10 of the cases where laboratorily claimed. There were cases of ascariasis, enterobiasis and trichocephalosis. According to data, there are 5 times less cases of trichocephalosis than of ascariasis. As for enterobiasis, it's less than ascariasis (the difference is 205 cases). In therms of the aging, all the cases occur more frequently in the group of children below the age of 14. PMID:23388532

  18. Spectral Features and Charge Dynamics of Lead Halide Perovskites: Origins and Interpretations.

    PubMed

    Sum, Tze Chien; Mathews, Nripan; Xing, Guichuan; Lim, Swee Sien; Chong, Wee Kiang; Giovanni, David; Dewi, Herlina Arianita

    2016-02-16

    Lead halide perovskite solar cells are presently the forerunner among the third generation solution-processed photovoltaic technologies. With efficiencies exceeding 20% and low production costs, they are prime candidates for commercialization. Critical insights into their light harvesting, charge transport, and loss mechanisms have been gained through time-resolved optical probes such as femtosecond transient absorption spectroscopy (fs-TAS), transient photoluminescence spectroscopy, and time-resolved terahertz spectroscopy. Specifically, the discoveries of long balanced electron-hole diffusion lengths and gain properties in halide perovskites underpin their significant roles in uncovering structure-function relations and providing essential feedback for materials development and device optimization. In particular, fs-TAS is becoming increasingly popular in perovskite characterization studies, with commercial one-box pump-probe systems readily available as part of a researcher's toolkit. Although TAS is a powerful probe in the study of charge dynamics and recombination mechanisms, its instrumentation and data interpretation can be daunting even for experienced researchers. This issue is exacerbated by the sensitive nature of halide perovskites where the kinetics are especially susceptible to pump fluence, sample preparation and handling and even degradation effects that could lead to disparate conclusions. Nonetheless, with end-users having a clear understanding of TAS's capabilities, subtleties, and limitations, cutting-edge work with deep insights can still be performed using commercial setups as has been the trend for ubiquitous spectroscopy instruments like absorption, fluorescence, and transient photoluminescence spectrometers. Herein, we will first briefly examine the photophysical processes in lead halide perovskites, highlighting their novel properties. Next, we proceed to give a succinct overview of the fundamentals of pump-probe spectroscopy in relation

  19. Radiogenomic analysis of breast cancer: dynamic contrast enhanced - magnetic resonance imaging based features are associated with molecular subtypes

    NASA Astrophysics Data System (ADS)

    Wang, Shijian; Fan, Ming; Zhang, Juan; Zheng, Bin; Wang, Xiaojia; Li, Lihua

    2016-03-01

    Breast cancer is one of the most common malignant tumor with upgrading incidence in females. The key to decrease the mortality is early diagnosis and reasonable treatment. Molecular classification could provide better insights into patient-directed therapy and prognosis prediction of breast cancer. It is known that different molecular subtypes have different characteristics in magnetic resonance imaging (MRI) examination. Therefore, we assumed that imaging features can reflect molecular information in breast cancer. In this study, we investigated associations between dynamic contrasts enhanced MRI (DCE-MRI) features and molecular subtypes in breast cancer. Sixty patients with breast cancer were enrolled and the MR images were pre-processed for noise reduction, registration and segmentation. Sixty-five dimensional imaging features including statistical characteristics, morphology, texture and dynamic enhancement in breast lesion and background regions were semiautomatically extracted. The associations between imaging features and molecular subtypes were assessed by using statistical analyses, including univariate logistic regression and multivariate logistic regression. The results of multivariate regression showed that imaging features are significantly associated with molecular subtypes of Luminal A (p=0.00473), HER2-enriched (p=0.00277) and Basal like (p=0.0117), respectively. The results indicated that three molecular subtypes are correlated with DCE-MRI features in breast cancer. Specifically, patients with a higher level of compactness or lower level of skewness in breast lesion are more likely to be Luminal A subtype. Besides, the higher value of the dynamic enhancement at T1 time in normal side reflect higher possibility of HER2-enriched subtype in breast cancer.

  20. Thermal structure and dynamics of the Jovian atmosphere. 2: Visible cloud features

    NASA Technical Reports Server (NTRS)

    Conrath, B. J.; Flasar, F. M.; Pirraglia, J. A.; Gierasch, P. J.; Hunt, G. E.

    1980-01-01

    Voyager IRIS data reveal strong similarities among a broad range of features which differ considerably in visual appearance. The atmosphere above anticyclonic features, including the major white ovals, the Great Red Spot, and a zone, are cold relative to the immediate surroundings in the upper troposphere and tropopause region. These results are consistent with upwelling and divergence in this part of the atmosphere. A hot spot and a barge, which are localized cyclonic features, are found to be warm relative to their surroundings, implying subsidence with accompanying convergence. In all cases, the thermal wind shear associated with the features indicates a decay of the vorticity with height in the upper troposphere and lower stratosphere. Vertical velocities inferred from the observed temperature perturbations imply an upper limit of vertical mixing times near the tropopause of approximately 20 years. Temperatures in the upper stratosphere above the anticyclonic features show considerable variation, but in most cases are found to be relatively warm.

  1. Study on human ophthalmomyiasis externa caused by Oestrus ovis larva, in Sirte-Libya: parasite features, clinical presentation and management.

    PubMed

    Fathy, Fouad M; El-Barghathi, Adam; El-Ahwal, Abdalla; El-Bagar, Shaban

    2006-04-01

    Oestrus ovis larva is by far the commonest cause of human ophthalmomyiasis. The larva usually limits it's activity to the conjunctiva and cornea, but, penetration of the eye is a potential complication. Misdiagnosis is common and the condition of acute catarrhal conjunctivitis is ascribed to other causes. The study included 20 patients referred to university hospital of Sirte, Libya. Results showed that the condition was more common among adult male shepherds and farmers in rural areas. Important criteria for diagnosis were; sudden mobile foreign body sensation with abrupt itching and lacrimation occurring in endemic area, in warm months even without history of fly strike. Effective treatment consisted of mechanical removal of the larva by the cotton swap mounting technique which resulted in rapid improvement. Suffocation of residual larvae was mediated by use of liberal amounts of topical antibiotics. Slit lamp examination of larva showed that it was small, translucent, avoid the light beam and easily overlooked. Detailed microscopic examination of larval surface structures revealed a multi-component attachment apparatus consisting of oral hooks, inter-segmental spines, caudal spines and a multi-layered spiny thoracic complex described for the first time. These injurious structures are believed to be responsible through inflicting direct mechanical damage for the observed haemorrhage, ulceration or even the potential invasion, as these changes were more obvious in neglected cases. So, early diagnosis and treatment are essential to avoid complications. PMID:16605116

  2. Loss-of-function HDAC8 mutations cause a phenotypic spectrum of Cornelia de Lange syndrome-like features, ocular hypertelorism, large fontanelle and X-linked inheritance

    PubMed Central

    Kaiser, Frank J.; Ansari, Morad; Braunholz, Diana; Concepción Gil-Rodríguez, María; Decroos, Christophe; Wilde, Jonathan J.; Fincher, Christopher T.; Kaur, Maninder; Bando, Masashige; Amor, David J.; Atwal, Paldeep S.; Bahlo, Melanie; Bowman, Christine M.; Bradley, Jacquelyn J.; Brunner, Han G.; Clark, Dinah; Del Campo, Miguel; Di Donato, Nataliya; Diakumis, Peter; Dubbs, Holly; Dyment, David A.; Eckhold, Juliane; Ernst, Sarah; Ferreira, Jose C.; Francey, Lauren J.; Gehlken, Ulrike; Guillén-Navarro, Encarna; Gyftodimou, Yolanda; Hall, Bryan D.; Hennekam, Raoul; Hudgins, Louanne; Hullings, Melanie; Hunter, Jennifer M.; Yntema, Helger; Innes, A. Micheil; Kline, Antonie D.; Krumina, Zita; Lee, Hane; Leppig, Kathleen; Lynch, Sally Ann; Mallozzi, Mark B.; Mannini, Linda; Mckee, Shane; Mehta, Sarju G.; Micule, Ieva; Mohammed, Shehla; Moran, Ellen; Mortier, Geert R.; Moser, Joe-Ann S.; Noon, Sarah E.; Nozaki, Naohito; Nunes, Luis; Pappas, John G.; Penney, Lynette S.; Pérez-Aytés, Antonio; Petersen, Michael B.; Puisac, Beatriz; Revencu, Nicole; Roeder, Elizabeth; Saitta, Sulagna; Scheuerle, Angela E.; Schindeler, Karen L.; Siu, Victoria M.; Stark, Zornitza; Strom, Samuel P.; Thiese, Heidi; Vater, Inga; Willems, Patrick; Williamson, Kathleen; Wilson, Louise C.; Hakonarson, Hakon; Quintero-Rivera, Fabiola; Wierzba, Jolanta; Musio, Antonio; Gillessen-Kaesbach, Gabriele; Ramos, Feliciano J.; Jackson, Laird G.; Shirahige, Katsuhiko; Pié, Juan; Christianson, David W.; Krantz, Ian D.; Fitzpatrick, David R.; Deardorff, Matthew A.

    2014-01-01

    Cornelia de Lange syndrome (CdLS) is a multisystem genetic disorder with distinct facies, growth failure, intellectual disability, distal limb anomalies, gastrointestinal and neurological disease. Mutations in NIPBL, encoding a cohesin regulatory protein, account for >80% of cases with typical facies. Mutations in the core cohesin complex proteins, encoded by the SMC1A, SMC3 and RAD21 genes, together account for ∼5% of subjects, often with atypical CdLS features. Recently, we identified mutations in the X-linked gene HDAC8 as the cause of a small number of CdLS cases. Here, we report a cohort of 38 individuals with an emerging spectrum of features caused by HDAC8 mutations. For several individuals, the diagnosis of CdLS was not considered prior to genomic testing. Most mutations identified are missense and de novo. Many cases are heterozygous females, each with marked skewing of X-inactivation in peripheral blood DNA. We also identified eight hemizygous males who are more severely affected. The craniofacial appearance caused by HDAC8 mutations overlaps that of typical CdLS but often displays delayed anterior fontanelle closure, ocular hypertelorism, hooding of the eyelids, a broader nose and dental anomalies, which may be useful discriminating features. HDAC8 encodes the lysine deacetylase for the cohesin subunit SMC3 and analysis of the functional consequences of the missense mutations indicates that all cause a loss of enzymatic function. These data demonstrate that loss-of-function mutations in HDAC8 cause a range of overlapping human developmental phenotypes, including a phenotypically distinct subgroup of CdLS. PMID:24403048

  3. Loss-of-function HDAC8 mutations cause a phenotypic spectrum of Cornelia de Lange syndrome-like features, ocular hypertelorism, large fontanelle and X-linked inheritance.

    PubMed

    Kaiser, Frank J; Ansari, Morad; Braunholz, Diana; Concepción Gil-Rodríguez, María; Decroos, Christophe; Wilde, Jonathan J; Fincher, Christopher T; Kaur, Maninder; Bando, Masashige; Amor, David J; Atwal, Paldeep S; Bahlo, Melanie; Bowman, Christine M; Bradley, Jacquelyn J; Brunner, Han G; Clark, Dinah; Del Campo, Miguel; Di Donato, Nataliya; Diakumis, Peter; Dubbs, Holly; Dyment, David A; Eckhold, Juliane; Ernst, Sarah; Ferreira, Jose C; Francey, Lauren J; Gehlken, Ulrike; Guillén-Navarro, Encarna; Gyftodimou, Yolanda; Hall, Bryan D; Hennekam, Raoul; Hudgins, Louanne; Hullings, Melanie; Hunter, Jennifer M; Yntema, Helger; Innes, A Micheil; Kline, Antonie D; Krumina, Zita; Lee, Hane; Leppig, Kathleen; Lynch, Sally Ann; Mallozzi, Mark B; Mannini, Linda; McKee, Shane; Mehta, Sarju G; Micule, Ieva; Mohammed, Shehla; Moran, Ellen; Mortier, Geert R; Moser, Joe-Ann S; Noon, Sarah E; Nozaki, Naohito; Nunes, Luis; Pappas, John G; Penney, Lynette S; Pérez-Aytés, Antonio; Petersen, Michael B; Puisac, Beatriz; Revencu, Nicole; Roeder, Elizabeth; Saitta, Sulagna; Scheuerle, Angela E; Schindeler, Karen L; Siu, Victoria M; Stark, Zornitza; Strom, Samuel P; Thiese, Heidi; Vater, Inga; Willems, Patrick; Williamson, Kathleen; Wilson, Louise C; Hakonarson, Hakon; Quintero-Rivera, Fabiola; Wierzba, Jolanta; Musio, Antonio; Gillessen-Kaesbach, Gabriele; Ramos, Feliciano J; Jackson, Laird G; Shirahige, Katsuhiko; Pié, Juan; Christianson, David W; Krantz, Ian D; Fitzpatrick, David R; Deardorff, Matthew A

    2014-06-01

    Cornelia de Lange syndrome (CdLS) is a multisystem genetic disorder with distinct facies, growth failure, intellectual disability, distal limb anomalies, gastrointestinal and neurological disease. Mutations in NIPBL, encoding a cohesin regulatory protein, account for >80% of cases with typical facies. Mutations in the core cohesin complex proteins, encoded by the SMC1A, SMC3 and RAD21 genes, together account for ∼5% of subjects, often with atypical CdLS features. Recently, we identified mutations in the X-linked gene HDAC8 as the cause of a small number of CdLS cases. Here, we report a cohort of 38 individuals with an emerging spectrum of features caused by HDAC8 mutations. For several individuals, the diagnosis of CdLS was not considered prior to genomic testing. Most mutations identified are missense and de novo. Many cases are heterozygous females, each with marked skewing of X-inactivation in peripheral blood DNA. We also identified eight hemizygous males who are more severely affected. The craniofacial appearance caused by HDAC8 mutations overlaps that of typical CdLS but often displays delayed anterior fontanelle closure, ocular hypertelorism, hooding of the eyelids, a broader nose and dental anomalies, which may be useful discriminating features. HDAC8 encodes the lysine deacetylase for the cohesin subunit SMC3 and analysis of the functional consequences of the missense mutations indicates that all cause a loss of enzymatic function. These data demonstrate that loss-of-function mutations in HDAC8 cause a range of overlapping human developmental phenotypes, including a phenotypically distinct subgroup of CdLS. PMID:24403048

  4. Editor's Highlight: Abrasion of Artificial Stones as a New Cause of an Ancient Disease. Physicochemical Features and Cellular Responses.

    PubMed

    Pavan, Cristina; Polimeni, Manuela; Tomatis, Maura; Corazzari, Ingrid; Turci, Francesco; Ghigo, Dario; Fubini, Bice

    2016-09-01

    New outbursts of silicosis were recently reported among workers manufacturing an engineered material known as "artificial stone," composed by high percentages of quartz (up to 98%) agglomerated with pigments and polymeric resins. Dusts released by abrasion during artificial stone polishing were characterized for particle size, morphology, and elemental composition and studied for (1) ability to catalyze free radical generation in acellular tests, (2) membranolytic potential on human erythrocytes, (3) cytotoxic activity (lactate dehydrogenase release) on murine alveolar macrophages (MH-S) and human bronchial epithelial (BEAS-2B) cell lines, (4) induction of epithelial-mesenchymal transition (EMT) in BEAS-2B cells. Min-U-Sil 5 was used as reference quartz. Artificial stone dusts exhibited morphological features close to quartz, but contained larger amount of metal transition ions (mainly, Fe, Cu, and Ti), potentially responsible for the high reactivity in free radical generation observed. Opposite to Min-U-Sil 5, they were neither hemolytic nor cytotoxic on MH-S cells, a low cytotoxicity only being observed with BEAS-2B cells. The presence on the particle surface of residues of the resin accounts for this attenuated behavior, as hemolysis appeared and cytotoxicity increased after thermal degradation of the resin, when the free quartz surface was exposed. All dusts induced EMT with loss of E-cadherin expression and increased the expression of mesenchymal proteins (α-smooth muscle actin and vimentin). This may contribute to explain the development of fibrosis on workers exposed to artificial stone dusts. PMID:27255382

  5. Capturing the musical brain with Lasso: Dynamic decoding of musical features from fMRI data.

    PubMed

    Toiviainen, Petri; Alluri, Vinoo; Brattico, Elvira; Wallentin, Mikkel; Vuust, Peter

    2014-03-01

    We investigated neural correlates of musical feature processing with a decoding approach. To this end, we used a method that combines computational extraction of musical features with regularized multiple regression (LASSO). Optimal model parameters were determined by maximizing the decoding accuracy using a leave-one-out cross-validation scheme. The method was applied to functional magnetic resonance imaging (fMRI) data that were collected using a naturalistic paradigm, in which participants' brain responses were recorded while they were continuously listening to pieces of real music. The dependent variables comprised musical feature time series that were computationally extracted from the stimulus. We expected timbral features to obtain a higher prediction accuracy than rhythmic and tonal ones. Moreover, we expected the areas significantly contributing to the decoding models to be consistent with areas of significant activation observed in previous research using a naturalistic paradigm with fMRI. Of the six musical features considered, five could be significantly predicted for the majority of participants. The areas significantly contributing to the optimal decoding models agreed to a great extent with results obtained in previous studies. In particular, areas in the superior temporal gyrus, Heschl's gyrus, Rolandic operculum, and cerebellum contributed to the decoding of timbral features. For the decoding of the rhythmic feature, we found the bilateral superior temporal gyrus, right Heschl's gyrus, and hippocampus to contribute most. The tonal feature, however, could not be significantly predicted, suggesting a higher inter-participant variability in its neural processing. A subsequent classification experiment revealed that segments of the stimulus could be classified from the fMRI data with significant accuracy. The present findings provide compelling evidence for the involvement of the auditory cortex, the cerebellum and the hippocampus in the processing of

  6. Human-caused mortality influences spatial population dynamics: pumas in landscapes with varying mortality risks

    USGS Publications Warehouse

    Newby, Jesse R.; Mills, L. Scott; Ruth, Toni K.; Pletscher, Daniel H.; Mitchell, Michael S.; Quigley, Howard B.; Murphy, Kerry M.; DeSimone, Rich

    2013-01-01

    An understanding of how stressors affect dispersal attributes and the contribution of local populations to multi-population dynamics are of immediate value to basic and applied ecology. Puma (Puma concolor) populations are expected to be influenced by inter-population movements and susceptible to human-induced source–sink dynamics. Using long-term datasets we quantified the contribution of two puma populations to operationally define them as sources or sinks. The puma population in the Northern Greater Yellowstone Ecosystem (NGYE) was largely insulated from human-induced mortality by Yellowstone National Park. Pumas in the western Montana Garnet Mountain system were exposed to greater human-induced mortality, which changed over the study due to the closure of a 915 km2 area to hunting. The NGYE’s population growth depended on inter-population movements, as did its ability to act as a source to the larger region. The heavily hunted Garnet area was a sink with a declining population until the hunting closure, after which it became a source with positive intrinsic growth and a 16× increase in emigration. We also examined the spatial and temporal characteristics of individual dispersal attributes (emigration, dispersal distance, establishment success) of subadult pumas (N = 126). Human-caused mortality was found to negatively impact all three dispersal components. Our results demonstrate the influence of human-induced mortality on not only within population vital rates, but also inter-population vital rates, affecting the magnitude and mechanisms of local population’s contribution to the larger metapopulation.

  7. Genetic Diversity and Dynamic Distribution of Mycobacterium tuberculosis Isolates Causing Pulmonary and Extrapulmonary Tuberculosis in Thailand

    PubMed Central

    Srilohasin, Prapaporn; Tokunaga, Katsushi; Nishida, Nao; Prammananan, Therdsak; Smittipat, Nat; Mahasirimongkol, Surakameth; Chaiyasirinroje, Boonchai; Yanai, Hideki; Palittapongarnpim, Prasit

    2014-01-01

    This study examined the genetic diversity and dynamicity of circulating Mycobacterium tuberculosis strains in Thailand using nearly neutral molecular markers. The single nucleotide polymorphism (SNP)-based genotypes of 1,414 culture-positive M. tuberculosis isolates from 1,282 pulmonary tuberculosis (PTB) and 132 extrapulmonary TB (EPTB) patients collected from 1995 to 2011 were characterized. Among the eight SNP cluster groups (SCG), SCG2 (44.1%), which included the Beijing (BJ) genotype, and SCG1 (39.4%), an East African Indian genotype, were dominant. Comparisons between the genotypes of M. tuberculosis isolates causing PTB and EPTB in HIV-negative cases revealed similar prevalence trends although genetic diversity was higher in the PTB patients. The identification of 10 reported sequence types (STs) and three novel STs was hypothesized to indicate preferential expansion of the SCG2 genotype, especially the modern BJ ST10 (15.6%) and ancestral BJ ST19 (13.1%). An association between SCG2 and SCG1 genotypes and particular patient age groups implies the existence of different genetic advantages among the bacterial populations. The results revealed that increasing numbers of young patients were infected with M. tuberculosis SCGs 2 and 5, which contrasts with the reduction of the SCG1 genotype. Our results indicate the selection and dissemination of potent M. tuberculosis genotypes in this population. The determination of heterogeneity and dynamic population changes of circulating M. tuberculosis strains in countries using the Mycobacterium bovis BCG (bacillus Calmette-Guérin) vaccine are beneficial for vaccine development and control strategies. PMID:25297330

  8. TGFB2 mutations cause familial thoracic aortic aneurysms and dissections associated with mild systemic features of Marfan syndrome.

    PubMed

    Boileau, Catherine; Guo, Dong-Chuan; Hanna, Nadine; Regalado, Ellen S; Detaint, Delphine; Gong, Limin; Varret, Mathilde; Prakash, Siddharth K; Li, Alexander H; d'Indy, Hyacintha; Braverman, Alan C; Grandchamp, Bernard; Kwartler, Callie S; Gouya, Laurent; Santos-Cortez, Regie Lyn P; Abifadel, Marianne; Leal, Suzanne M; Muti, Christine; Shendure, Jay; Gross, Marie-Sylvie; Rieder, Mark J; Vahanian, Alec; Nickerson, Deborah A; Michel, Jean Baptiste; Jondeau, Guillaume; Milewicz, Dianna M

    2012-08-01

    A predisposition for thoracic aortic aneurysms leading to acute aortic dissections can be inherited in families in an autosomal dominant manner. Genome-wide linkage analysis of two large unrelated families with thoracic aortic disease followed by whole-exome sequencing of affected relatives identified causative mutations in TGFB2. These mutations-a frameshift mutation in exon 6 and a nonsense mutation in exon 4-segregated with disease with a combined logarithm of odds (LOD) score of 7.7. Sanger sequencing of 276 probands from families with inherited thoracic aortic disease identified 2 additional TGFB2 mutations. TGFB2 encodes transforming growth factor (TGF)-β2, and the mutations are predicted to cause haploinsufficiency for TGFB2; however, aortic tissue from cases paradoxically shows increased TGF-β2 expression and immunostaining. Thus, haploinsufficiency for TGFB2 predisposes to thoracic aortic disease, suggesting that the initial pathway driving disease is decreased cellular TGF-β2 levels leading to a secondary increase in TGF-β2 production in the diseased aorta. PMID:22772371

  9. Low doses of mercuric chloride cause the main features of anti-nucleolar autoimmunity in female outbred CFW mice.

    PubMed

    Arefieva, Alla S; Kamaeva, Alfia G; Krasilshchikova, Marina S

    2016-09-01

    The growth of the influence of anthropogenic factors aimed on the improvement of human life has its side effect, for example, living organisms receive increasing exposure to toxic mercuric compounds. Experimental data show that mercury (Hg) salts are able to induce systemic autoimmunity in rodents. This Hg-induced autoimmune process (HgIA) is characterized by T cell-dependent polyclonal activation of B lymphocytes, increased level of serum immunoglobulin G1 (IgG1) and immunoglobulin E (IgE), production of antinucleolar autoantibodies (ANoA), and immune complex deposition in multiple organs. HgIA in mice is used as a model of human systemic autoimmune disorders. However, the dose of mercuric chloride (HgCl2) usually used in laboratory mice to induce HgIA is above the allowable limit for everyday levels of Hg exposure in humans. So, we decided to determine the lowest dose of HgCl2 that is able to trigger autoimmunity in outbred Carworth Farms Swiss Webster (CFW) mice not genetically prone to HgIA development. The lowest dose (50 µg/kg body weight (b.w.)/week) was chosen to match the World Health Organization provisional weekly tolerable intake of total Hg for humans. We also tested HgCl2 at 500 and 1500 µg/kg b.w./week (6.5- and 2-fold less than usually used for induction of HgIA in mice). We found that even the lowest dose of Hg resulted in a statistically significant increase in serum level of IgG1 after 8 weeks of treatment. HgCl2 in doses 500 and 1500 µg/kg b.w./week resulted in a significant increase in serum level of IgG1 after 4 weeks of treatment, followed by ANoA production. Sera of HgCl2-treated mice stained the regions in which the major autoantigen in HgIA, fibrillarin, was revealed. These results suggest that low doses of Hg are able to induce the main features of HgIA in genetically heterozygous mice, and that humans chronically exposed to low doses of Hg may be at risk of autoimmunity induction regardless of their genetic background. PMID:25765285

  10. A dynamic image recognition method for sleeper springs trouble of moving freight cars based on Haar features

    NASA Astrophysics Data System (ADS)

    Zhou, Fuqiang; Jiang, Yuan; Zhang, Guangjun

    2006-11-01

    A novel conception of automatic recognition for free-trouble sleeper springs is proposed and Adaboost algorithm based on Haar features is applied for the sleeper springs recognition in Trouble of moving Freight car Detection System (TFDS). In the recognition system, feature set of sleeper springs is determined by Haar features and selected by Adaboost algorithm. In order to recognize and select the free-trouble sleeper springs from all the captured dynamic images, a cascade of classifier is established by searching dynamic images. The amount of detected images is drastically reduced and the recognition efficiency is improved due to the conception of free-trouble recognition. Experiments show that the proposed method is characterized by simple feature, high efficiency and robustness. It performs high robustness against noise as well as translation, rotation and scale transformations of objects and indicates high stability to images with poor quality such as low resolution, partial occlusion, poor illumination and overexposure etc. The recognition time of a 640×480 image is about 16ms, and Correct Detection Rate is high up to about 97%, while Miss Detection Rate and Error Detection Rate are very low. The proposed method can recognize sleeper springs in all-weather conditions, which advances the engineering application for TFDS.

  11. Omnidirectional Audio-Visual Talker Localization Based on Dynamic Fusion of Audio-Visual Features Using Validity and Reliability Criteria

    NASA Astrophysics Data System (ADS)

    Denda, Yuki; Nishiura, Takanobu; Yamashita, Yoichi

    This paper proposes a robust omnidirectional audio-visual (AV) talker localizer for AV applications. The proposed localizer consists of two innovations. One of them is robust omnidirectional audio and visual features. The direction of arrival (DOA) estimation using an equilateral triangular microphone array, and human position estimation using an omnidirectional video camera extract the AV features. The other is a dynamic fusion of the AV features. The validity criterion, called the audioor visual-localization counter, validates each audio- or visual-feature. The reliability criterion, called the speech arriving evaluator, acts as a dynamic weight to eliminate any prior statistical properties from its fusion procedure. The proposed localizer can compatibly achieve talker localization in a speech activity and user localization in a non-speech activity under the identical fusion rule. Talker localization experiments were conducted in an actual room to evaluate the effectiveness of the proposed localizer. The results confirmed that the talker localization performance of the proposed AV localizer using the validity and reliability criteria is superior to that of conventional localizers.

  12. Dynamic Overshoot Near Trench Caused by Large Asperity Break at Depth

    NASA Astrophysics Data System (ADS)

    Fukuyama, Eiichi; Hok, Sébastien

    2015-08-01

    In an attempt to explain the large shallow slip that occurred near the trench during the 2011 Tohoku-Oki earthquake, numerical simulations of earthquake dynamic rupture were carried out using a fault model with a subduction interface containing a bump-shaped asperity, which might result from subduction of an old submarine volcano or seamount. It was assumed that during the interseismic period, slip only occurs outside the bump area and that stress accumulates inside the bump, creating a seismogenic asperity. We roughly evaluated the amount of slip outside the bump during the interseismic period, assuming a constant long-term subduction rate. Then we could estimate the accumulated stress inside the bump. We constructed the initial stress distribution based on the stress change caused by the slip-deficit distribution. A constitutive relation was constructed based on a slip-weakening friction law and was used to compute spontaneous ruptures. The results indicate that a large slip can occur between the trench and the bump, even though a very small amount of stress is accumulated there before the rupture. This is due to an interaction between the free surface and the fault that causes slip overshoot. On the region of the fault below the bump, such overshoot cannot occur because the fault is pinned by the deeper un-slipped zone. However, on the shallower side, the edge of the fault becomes free when the rupture approaches the free surface. In this region, such a large slip can occur without releasing a large amount of stress.

  13. Infection dynamics in frog populations with different histories of decline caused by a deadly disease.

    PubMed

    Sapsford, Sarah J; Voordouw, Maarten J; Alford, Ross A; Schwarzkopf, Lin

    2015-12-01

    Pathogens can drive host population dynamics. Chytridiomycosis is a fungal disease of amphibians that is caused by the fungus Batrachochytrium dendrobatidis (Bd). This pathogen has caused declines and extinctions in some host species whereas other host species coexist with Bd without suffering declines. In the early 1990s, Bd extirpated populations of the endangered common mistfrog, Litoria rheocola, at high-elevation sites, while populations of the species persisted at low-elevation sites. Today, populations have reappeared at many high-elevation sites where they presently co-exist with the fungus. We conducted a capture-mark-recapture (CMR) study of six populations of L. rheocola over 1 year, at high and low elevations. We used multistate CMR models to determine which factors (Bd infection status, site type, and season) influenced rates of frog survival, recapture, infection, and recovery from infection. We observed Bd-induced mortality of individual frogs, but did not find any significant effect of Bd infection on the survival rate of L. rheocola at the population level. Survival and recapture rates depended on site type and season. Infection rate was highest in winter when temperatures were favourable for pathogen growth, and differed among site types. The recovery rate was high (75.7-85.8%) across seasons, and did not differ among site types. The coexistence of L. rheocola with Bd suggests that (1) frog populations are becoming resistant to the fungus, (2) Bd may have evolved lower virulence, or (3) current environmental conditions may be inhibiting outbreaks of the fatal disease. PMID:26293680

  14. Association between dynamic features of breast DCE-MR imaging and clinical response of neoadjuvant chemotherapy: a preliminary analysis

    NASA Astrophysics Data System (ADS)

    Huang, Lijuan; Fan, Ming; Li, Lihua; Zhang, Juan; Shao, Guoliang; Zheng, Bin

    2016-03-01

    Neoadjuvant chemotherapy (NACT) is being used increasingly in the management of patients with breast cancer for systemically reducing the size of primary tumor before surgery in order to improve survival. The clinical response of patients to NACT is correlated with reduced or abolished of their primary tumor, which is important for treatment in the next stage. Recently, the dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) is used for evaluation of the response of patients to NACT. To measure this correlation, we extracted the dynamic features from the DCE- MRI and performed association analysis between these features and the clinical response to NACT. In this study, 59 patients are screened before NATC, of which 47 are complete or partial response, and 12 are no response. We segmented the breast areas depicted on each MR image by a computer-aided diagnosis (CAD) scheme, registered images acquired from the sequential MR image scan series, and calculated eighteen features extracted from DCE-MRI. We performed SVM with the 18 features for classification between patients of response and no response. Furthermore, 6 of the 18 features are selected to refine the classification by using Genetic Algorithm. The accuracy, sensitivity and specificity are 87%, 95.74% and 50%, respectively. The calculated area under a receiver operating characteristic (ROC) curve is 0.79+/-0.04. This study indicates that the features of DCE-MRI of breast cancer are associated with the response of NACT. Therefore, our method could be helpful for evaluation of NACT in treatment of breast cancer.

  15. Experimental and numerical study on the dynamic pressure caused by the bubble jet

    NASA Astrophysics Data System (ADS)

    Li, S.; Zhang, A. M.; Yao, X. L.

    2015-12-01

    The high speed liquid jet is an important mechanism of damage to hydraulic machinery by cavitation bubbles, as well as damage to vessels by underwater explosion bubble. In this study, the bubble motion near a wall and the pressure impulse are investigated through experimental and numerical methods. In the experiment, the bubble is generated by the electric discharge, and a high speed camera is used to capture the bubble motion. Numerical studies are conducted using the boundary element method, and the vortex ring model is adopted to deal with the discontinued potential of the toroidal bubble. Calculated results show excellent agreement with experimental observations. Meanwhile, the dynamic pressure caused by the bubble in the flow domain is calculated by an auxiliary function, which improves the accuracy of the results. A highly localized pressure region will be generated on the wall by the bubble jet. The optimal stand-off parameter (the ratio of the distance the bubble center at inception from the wall to the maximum bubble radius) for a most damaging jet formation is around 0.9.

  16. On the Causes and Dynamics of the Early Twentieth Century North American Pluvial

    NASA Technical Reports Server (NTRS)

    Cook, Benjamin I.; Seager, Richard; Miller, Ron L.

    2011-01-01

    The early twentieth century North American pluvial (1905-1917) was one of the most extreme wet periods of the last five hundred years and directly led to overly generous water allotments in the water-limited American West. Here we examine the causes and dynamics of the pluvial event using a combination of observation-based data sets and general circulation model (GCM) experiments. The character of the moisture surpluses during the pluvial differed by region, alternately driven by increased precipitation (the Southwest), low evaporation from cool temperatures (the Central Plains), or a combination of the two (the Pacific Northwest). Cool temperature anomalies covered much of the west and persisted through most months, part of a globally extensive period of cooler land and sea surface temperatures (SST). Circulation during boreal winter favored increased moisture import and precipitation in the southwest, while other regions and seasons were characterized by near normal or reduced precipitation. Anomalies in the mean circulation, precipitation, and SST fields are partially consistent with the relatively weak El Nino forcing during the pluvial, and also reflect the impact of positive departures in the Arctic Oscillation that occurred in ten of the thirteen pluvial winters. Differences between the reanalysis dataset, an independent statistical drought model, and GCM simulations highlight some of the remaining uncertainties in understanding the full extent of SST forcing of North American hydroclimatic variability.

  17. Transmission Dynamics of the Recently-Identified BYD Virus Causing Duck Egg-Drop Syndrome

    PubMed Central

    Vaidya, Naveen K.; Wang, Feng-bin; Zou, Xingfu; Wahl, Lindi M.

    2012-01-01

    Baiyangdian (BYD) virus is a recently-identified mosquito-borne flavivirus that causes severe disease in ducks, with extremely rapid transmission, up to 15% mortality within 10 days and 90% reduction in egg production on duck farms within 5 days of infection. Because of the zoonotic nature of flaviviruses, the characterization of BYD virus and its epidemiology are important public health concerns. Here, we develop a mathematical model for the transmission dynamics of this novel virus. We validate the model against BYD outbreak data collected from duck farms in Southeast China, as well as experimental data obtained from an animal facility. Based on our model, the basic reproductive number of BYD virus is high (R0 = 21) indicating that this virus is highly transmissible, consistent with the dramatic epidemiology observed in BYDV-affected duck farms. Our results indicate that younger ducks are more vulnerable to BYD disease and that ducks infected with BYD virus reduce egg production (to about 33% on average) for about 3 days post-infection; after 3 days infected ducks are no longer able to produce eggs. Using our model, we predict that control measures which reduce contact between mosquitoes and ducks such as mosquito nets are more effective than insecticides. PMID:22529985

  18. Transmission dynamics of the recently-identified BYD virus causing duck egg-drop syndrome.

    PubMed

    Vaidya, Naveen K; Wang, Feng-bin; Zou, Xingfu; Wahl, Lindi M

    2012-01-01

    Baiyangdian (BYD) virus is a recently-identified mosquito-borne flavivirus that causes severe disease in ducks, with extremely rapid transmission, up to 15% mortality within 10 days and 90% reduction in egg production on duck farms within 5 days of infection. Because of the zoonotic nature of flaviviruses, the characterization of BYD virus and its epidemiology are important public health concerns. Here, we develop a mathematical model for the transmission dynamics of this novel virus. We validate the model against BYD outbreak data collected from duck farms in Southeast China, as well as experimental data obtained from an animal facility. Based on our model, the basic reproductive number of BYD virus is high (R(0) = 21) indicating that this virus is highly transmissible, consistent with the dramatic epidemiology observed in BYDV-affected duck farms. Our results indicate that younger ducks are more vulnerable to BYD disease and that ducks infected with BYD virus reduce egg production (to about 33% on average) for about 3 days post-infection; after 3 days infected ducks are no longer able to produce eggs. Using our model, we predict that control measures which reduce contact between mosquitoes and ducks such as mosquito nets are more effective than insecticides. PMID:22529985

  19. Conformational features of an actuator containing calix[4]arene and thiophene: a molecular dynamics study.

    PubMed

    Zanuy, David; Casanovas, Jordi; Aleman, Carlos

    2006-05-25

    Molecular dynamics simulations have been performed for poly(calix[4]arene bis(bithiophene)) in dichloromethane solution. This material responds to its electronic structure variations with significant conformational changes, producing contraction-expansion movements. Simulations have been performed for the three states of this molecular actuator (reduced, oxidized-nondeprotonated, and oxidized-deprotonated), a specific force-field being developed for each case. Results, which are fully consistent with previous ab initio quantum mechanical calculations on an isolated actuating unit, have revealed important findings about the dynamics of the system. Analyses of the flexibility/rigidity of the molecular chain with the state, the interaction of the polymer with the solvent molecules and the influence of environmental factors (as the viscosity of solvent, the counterions and the thermal agitation) on the dynamics have provided important insights to the actuation mechanism. PMID:16706442

  20. Distribution of Spiral Galaxies in the Virgo and Fornax Clusters and Their Dynamic Features

    NASA Astrophysics Data System (ADS)

    Kogoshvili, N. G.; Borchkhadze, T. M.; Kalloghlian, A. T.

    2014-12-01

    The dynamic characteristics of spiral galaxies with absolute magnitudes M ≥ -20m.6 in the Virgo and Fornax clusters are studied using data from the Merged Catalog of Galaxies MERCG. The galactic diameters from MERCG are used to determine the radius RD that defines the region of possible concentration of dark matter, and the dynamic parameters Mdyn and Mdyn/LB of the spiral galaxies are calculated based on the centrifugal equilibrium condition. Results from the theory of angular momentum transfer are used to estimate the central surface density m0 and angular momentum K of stars in these galaxies. A comparison of the dynamic parameters of the spiral galaxies with M ≥ -20.6 and M ≤ -20.6 reveals a statistically significant higher fraction of dark matter in the spiral galaxies with M ≤ -20.6, at 26.3% in Virgo and 27% in Fornax.

  1. Unique Features of Dynamic Isotope Power Systems for High-Requirements Spacecraft

    SciTech Connect

    Raab, Bernard

    1980-08-01

    The Dynamic Isotope Power System, designed for spacecraft requiring prime power in the 500-to-2000 watt range, has been successfully built and ground tested. A number of studies, summarized herein, have demonstrated the advantages of using such a power system instead of the conventional solar system, for a variety of earth-orbit missions. These advantages stem from the unique nature of the dynamic isotope system, different in kind from solar power systems. As a result, in many cases, the spacecraft design can be significantly simplified and more closely harmonized with mission requirements. This overall advantage can be crucial in missions which have stringent pointing, stability, viewing and/or positioning requirements.

  2. Causes, Dynamics and Impacts of Lahars Generated by the April, 2015 Calbuco Eruption, Chile.

    NASA Astrophysics Data System (ADS)

    Russell, A. J.; Dussaillant, A. R.; Meier, C. I.; Rivera, A.; Barra, M. M.; Urzua, N. G.; Hernandez, J. F.; Napoleoni, F.; Gonzalez, C.

    2015-12-01

    Calbuco is a 2015m high, glacier capped, stratovolcano in the heavily populated Los Lagos district of southern Chile with a history of large volcanic eruptions in 1893-95, 1906-7, 1911-12, 1917, 1932, 1945, 1961 and 1972. Calbuco experienced a powerful 90 minute eruption at 18:04h on 22 April, 2015 followed by additional major eruptions at 01:00h and 13:10h on 23 & 30 April, respectively, resulting in the evacuation of 6500 people and the imposition of a 20 km radius exclusion zone. Pyroclastic flows descended into several river catchments radiating from the volcano with lahars travelling distances of up to 14 km, reaching populated areas. We present preliminary findings regarding the causes, dynamics and impacts of lahars generated by the April 2015 eruption. Pyroclastic flows melted glacier ice and snow generating the largest lahars in the Rio Este and Rio Blanco Sur on the southern flanks of the volcano. Lahar deposits in the Rio Blanco Norte were buried by pyroclastic flow deposits with measured temperatures of up to 282°C three months after emplacement. Lahar erosional impacts included bedrock erosion, alluvial channel incision, erosion of surficial deposits and the felling of large areas of forest. Depositional landforms included boulder run-ups on the outsides of channel bends, boulder clusters and large woody debris jams. Lahars deposited up to 8m of sediment within distal reaches. Deposits on the southern flanks of Calbuco indicate the passage of multiple pulses of contrasting rheology. Lahar occurrence and magnitude was controlled by the pre-eruption distribution of snow and ice on the volcano. Pre-existing lahar channels controlled flows to lower piedmont zones where routing was determined by palaeo lahar geomorphology. Ongoing erosion of proximal pyroclastic flow and lahar deposits provides large volumes of sediment to distal portions of fluvial systems radiating from Calbuco.

  3. Dynamic Measurements of Greenhouse Gas Respirations Caused by Changing Oxygen Levels

    NASA Astrophysics Data System (ADS)

    Fleck, D.; Saad, N.

    2015-12-01

    The necessity for constant monitoring of greenhouse gases (GHGs) is clearly evident now more than ever. Moreover, interpreting and understanding the processes that dictate the production and consumption of these gases will allow for proper management of GHGs in order to mitigate its detrimental climate effects. Presence of oxygen, or lack of it, is the driving force for determining pathways within biochemical redox reactions. Experiments to find correlations between oxygen and greenhouse gases have helped us understand photosynthesis, denitrification and beyond. Within the past few years measurements of O2 and nitrous oxide have been used over a wide ranging array of disciplines; from studying avenues for redox chemistry to characterizing gas profiles in sputum of cystic fibrosis patients. We present a full analysis solution, based on cavity ring-down spectroscopy, for simultaneous measurements of N2O, CO2, CH4, H2O, NH3, and O2 concentrations in soil flux, in order to better understand dynamics of ecological and biogeochemical processes. The stability and high temporal resolution of the five-species CRDS analyzer, coupled with a continuous high-precision O2 measurement (1-σ <200ppm) produces a complete picture of biogeochemical processes, for which a multitude of additional research experiments can be conceived. Adding another dimension to explore to help determine the rate at which these greenhouse gases are produced or consumed, allows scientists to further address fundamental scientific questions. Data is presented showing precision, drift and limitations of the O2 sensor measurement as well as the validity of spectroscopic corrections with the CRDS analyzer caused by changing O2. Experimental data is also presented to explore correlations of soil respiration rates of N2O, CO2 and CH4 due to differing soil O2 contents at varying timescales from minutes to days.

  4. Preface: Special issue featuring papers from the International Conference on Nonequilibrium Carrier Dynamics in Semiconductors

    NASA Astrophysics Data System (ADS)

    Reggiani, L.; Bordone, P.; Brunetti, R.

    2004-02-01

    The International Conference on Nonequilibrium Carrier Dynamics in Semiconductors (HCIS-13) celebrates 30 years since it first took place in Modena. Nonequilibrium dynamics of charge carriers, pioneered by the hot-electron concept, is an important issue for understanding electro-optic transport properties in semiconductor materials and structures. In these 30 years several topics have matured, and new ones have emerged thus fertilizing the field with a variety of physical problems and new ideas. The history of the conference is summarized in the opening paper `30 years of HCIS'. The future of the conference seems secure considering the continued lively interest of the participants. The conference addressed eleven major topics which constitute the backbone of the proceedings and are summarized as follows: carrier transport in low dimensional and nanostructure systems, nonequilibrium carriers in superlattices and devices, small devices and related phenomena, carrier dynamics and fluctuations, carrier quantum dynamics, coherent/incoherent carrier dynamics of optical excitations and ultra-fast optical phenomena, nonlinear optical effects, transport in organic matter, semiconductor-based spintronics, coherent dynamics in solid state systems for quantum processing and communication, novel materials and devices. Nanometric space scale and femtosecond time scale represent the ultimate domains of theoretical, experimental and practical interest. Traditional fields such as bulk properties, quantum transport, fluctuations and chaotic phenomena, etc, have received thorough and continuous attention. Emerging fields from previous conferences, such as quantum processing and communication, have been better assessed. New fields, such as spintronics and electron transport in organic matter, have appeared for the first time. One plenary talk, 11 invited talks, 230 submitted abstracts covering all these topics constituted a single-session conference. Following scientific selection

  5. Vanishing amplitude of backbone dynamics causes a true protein dynamical transition: 2H NMR studies on perdeuterated C-phycocyanin.

    PubMed

    Kämpf, Kerstin; Kremmling, Beke; Vogel, Michael

    2014-03-01

    Using a combination of H2 nuclear magnetic resonance (NMR) methods, we study internal rotational dynamics of the perdeuterated protein C-phycocyanin (CPC) in dry and hydrated states over broad temperature and dynamic ranges with high angular resolution. Separating H2 NMR signals from methyl deuterons, we show that basically all backbone deuterons exhibit highly restricted motion occurring on time scales faster than microseconds. The amplitude of this motion increases when a hydration shell exists, while it decreases upon cooling and vanishes near 175 K. We conclude that the vanishing of the highly restricted motion marks a dynamical transition, which is independent of the time window and of a fundamental importance. This conclusion is supported by results from experimental and computational studies of the proteins myoglobin and elastin. In particular, we argue based on findings in molecular dynamics simulations that the behavior of the highly restricted motion of proteins at the dynamical transition resembles that of a characteristic secondary relaxation of liquids at the glass transition, namely the nearly constant loss. Furthermore, H2 NMR studies on perdeuterated CPC reveal that, in addition to highly restricted motion, small fractions of backbone segments exhibit weakly restricted dynamics when temperature and hydration are sufficiently high. PMID:24730877

  6. Vanishing amplitude of backbone dynamics causes a true protein dynamical transition: H2 NMR studies on perdeuterated C-phycocyanin

    NASA Astrophysics Data System (ADS)

    Kämpf, Kerstin; Kremmling, Beke; Vogel, Michael

    2014-03-01

    Using a combination of H2 nuclear magnetic resonance (NMR) methods, we study internal rotational dynamics of the perdeuterated protein C-phycocyanin (CPC) in dry and hydrated states over broad temperature and dynamic ranges with high angular resolution. Separating H2 NMR signals from methyl deuterons, we show that basically all backbone deuterons exhibit highly restricted motion occurring on time scales faster than microseconds. The amplitude of this motion increases when a hydration shell exists, while it decreases upon cooling and vanishes near 175 K. We conclude that the vanishing of the highly restricted motion marks a dynamical transition, which is independent of the time window and of a fundamental importance. This conclusion is supported by results from experimental and computational studies of the proteins myoglobin and elastin. In particular, we argue based on findings in molecular dynamics simulations that the behavior of the highly restricted motion of proteins at the dynamical transition resembles that of a characteristic secondary relaxation of liquids at the glass transition, namely the nearly constant loss. Furthermore, H2 NMR studies on perdeuterated CPC reveal that, in addition to highly restricted motion, small fractions of backbone segments exhibit weakly restricted dynamics when temperature and hydration are sufficiently high.

  7. Quasi-similar decameter emission features appearing in the solar and jovian dynamic spectra

    NASA Astrophysics Data System (ADS)

    Litvinenko, G. V.; Shaposhnikov, V. E.; Konovalenko, A. A.; Zakharenko, V. V.; Panchenko, M.; Dorovsky, V. V.; Brazhenko, A. I.; Rucker, H. O.; Vinogradov, V. V.; Melnik, V. N.

    2016-07-01

    We investigate the dynamic spectra of the Sun and jovian decametric radiation obtained by the authors with the radio telescopes UTR-2 and URAN-2 (Kharkov, Poltava, Ukraine). We focus on the similar structures that appear on the dynamic spectra of those objects: S-bursts, drifting pairs, absorption bursts and zebra patterns. Similarity in structures allows us to assume that the plasma processes in the solar corona and in the jovian magnetosphere might have similar properties. We analyze and compare the main parameters of those structures and describe briefly some mechanisms of their generation that have already discussed in publications. We selected the mechanisms which, in our opinion, most completely and consistently explain the properties of the structures under consideration.

  8. Optimization of a 3D Dynamic Culturing System for In Vitro Modeling of Frontotemporal Neurodegeneration-Relevant Pathologic Features.

    PubMed

    Tunesi, Marta; Fusco, Federica; Fiordaliso, Fabio; Corbelli, Alessandro; Biella, Gloria; Raimondi, Manuela T

    2016-01-01

    Frontotemporal lobar degeneration (FTLD) is a severe neurodegenerative disorder that is diagnosed with increasing frequency in clinical setting. Currently, no therapy is available and in addition the molecular basis of the disease are far from being elucidated. Consequently, it is of pivotal importance to develop reliable and cost-effective in vitro models for basic research purposes and drug screening. To this respect, recent results in the field of Alzheimer's disease have suggested that a tridimensional (3D) environment is an added value to better model key pathologic features of the disease. Here, we have tried to add complexity to the 3D cell culturing concept by using a microfluidic bioreactor, where cells are cultured under a continuous flow of medium, thus mimicking the interstitial fluid movement that actually perfuses the body tissues, including the brain. We have implemented this model using a neuronal-like cell line (SH-SY5Y), a widely exploited cell model for neurodegenerative disorders that shows some basic features relevant for FTLD modeling, such as the release of the FTLD-related protein progranulin (PRGN) in specific vesicles (exosomes). We have efficiently seeded the cells on 3D scaffolds, optimized a disease-relevant oxidative stress experiment (by targeting mitochondrial function that is one of the possible FTLD-involved pathological mechanisms) and evaluated cell metabolic activity in dynamic culture in comparison to static conditions, finding that SH-SY5Y cells cultured in 3D scaffold are susceptible to the oxidative damage triggered by a mitochondrial-targeting toxin (6-OHDA) and that the same cells cultured in dynamic conditions kept their basic capacity to secrete PRGN in exosomes once recovered from the bioreactor and plated in standard 2D conditions. We think that a further improvement of our microfluidic system may help in providing a full device where assessing basic FTLD-related features (including PRGN dynamic secretion) that may be

  9. Wrisberg-variant discoid lateral meniscus: current concepts, treatment options, and imaging features with emphasis on dynamic ultrasonography.

    PubMed

    Jose, Jean; Buller, Leonard T; Rivera, Sebastian; Carvajal Alba, Jaime A; Baraga, Michael

    2015-03-01

    Discoid lateral menisci represent a range of morphologic abnormalities of the lateral meniscus. The Wrisberg-variant discoid lateral meniscus is an unstable type that lacks posterior ligament attachments, resulting in "snapping knee syndrome." Abnormally mobile discoid lateral menisci are difficult to diagnose both clinically and with traditional static imaging, such as magnetic resonance imaging. In this article, we discuss the pathophysiology, clinical features, imaging findings, and treatment options for Wrisberg-variant discoid lateral menisci. We focus on the role of dynamic ultrasonography in revealing lateral meniscal subluxation during provocative maneuvers. PMID:25750948

  10. Two-Phase ({gamma},{alpha}) Equation of State for Cerium and Features of its Dynamic Compression

    SciTech Connect

    Yelkin, V. M.; Kozlov, E. A.; Kakshina, E. V.; Moreva, Yu. S.

    2006-07-28

    The unusual thermodynamic properties of cerium result from features in the narrow 4f-zone whose electrons are subdivided into localized and delocalized subsystems. In this paper the model of pseudo-binary solid solutions allowing for two different electronic states is applied to construct the thermodynamically complete two-phase equation of state for cerium. The parameters of the model were fitted to describe the thermodynamic data obtained in the static experiments with high-purity cerium. This equation of state was used to analyze wave structures realized under dynamic compression with regard to the equilibrium ({gamma},{alpha}) phase transition.

  11. Electrochemical machining with ultrashort voltage pulses: modelling of charging dynamics and feature profile evolution.

    PubMed

    Kenney, Jason A; Hwang, Gyeong S

    2005-07-01

    A two-dimensional computational model is developed to describe electrochemical nanostructuring of conducting materials with ultrashort voltage pulses. The model consists of (1) a transient charging simulation to describe the evolution of the overpotentials at the tool and workpiece surfaces and the resulting dissolution currents and (2) a feature profile evolution tool which uses the level set method to describe either vertical or lateral etching of the workpiece. Results presented include transient currents at different separations between tool and workpiece, evolution of overpotentials and dissolution currents as a function of position along the workpiece, and etch profiles as a function of pulse duration. PMID:21727446

  12. On some long time dynamical features of the Trojan asteroids of Jupiter

    NASA Astrophysics Data System (ADS)

    Érdi, Bálint; Forgács-Dajka, Emese; Süli, Áron

    2013-09-01

    The equation of motion of long periodic libration around the Lagrangian point in the restricted three-body problem is investigated. The range of validity of an approximate analytical solution in the tadpole region is determined by numerical integration. The predictions of the model of libration are tested on the Trojan asteroids of Jupiter. The long time evolution of the orbital eccentricity and the longitude of the perihelion of the Trojan asteroids, under the effect of the four giant planets, is also investigated and a slight dynamical asymmetry is shown between the two groups of Trojans at and.

  13. Low Band Gap Coplanar Conjugated Molecules Featuring Dynamic Intramolecular Lewis Acid-Base Coordination.

    PubMed

    Zhu, Congzhi; Guo, Zi-Hao; Mu, Anthony U; Liu, Yi; Wheeler, Steven E; Fang, Lei

    2016-05-20

    Ladder-type conjugated molecules with a low band gap and low LUMO level were synthesized through an N-directed borylation reaction of pyrazine-derived donor-acceptor-donor precursors. The intramolecular boron-nitrogen coordination bonds played a key role in rendering the rigid and coplanar conformation of these molecules and their corresponding electronic structures. Experimental investigation and theoretical simulation revealed the dynamic nature of such coordination, which allowed for active manipulation of the optical properties of these molecules by using competing Lewis basic solvents. PMID:27096728

  14. An NMR and molecular dynamics investigation of the avian prion hexarepeat conformational features in solution

    NASA Astrophysics Data System (ADS)

    Pietropaolo, Adriana; Raiola, Luca; Muccioli, Luca; Tiberio, Giustiniano; Zannoni, Claudio; Fattorusso, Roberto; Isernia, Carla; Mendola, Diego La; Pappalardo, Giuseppe; Rizzarelli, Enrico

    2007-07-01

    The prion protein is a copper binding glycoprotein that in mammals can misfold into a pathogenic isoform leading to prion diseases, as opposed, surprisingly, to avians. The avian prion N-terminal tandem repeat is richer in prolines than the mammal one, and understanding their effect on conformation is of great biological importance. Here we succeeded in investigating the conformations of a single avian hexarepeat by means of NMR and molecular dynamics techniques. We found a high flexibility and a strong conformational dependence on pH: local turns are present at acidic and neutral pH, while unordered regions dominate at basic conditions.

  15. Special Features of the Structure of Copper-containing Products of Plasma Dynamic Synthesis

    NASA Astrophysics Data System (ADS)

    Ivashutenko, A. S.; Nazarenko, O. B.; Sivkov, A. A.; Saigash, A. S.; Stepanov, K. I.

    2015-03-01

    Results of investigation of the dispersed, phase, and chemical compositions of products of plasma dynamic synthesis in a high-speed pulsed jet of copper-containing electroerosive plasma flowing into a closed volume with the air atmosphere are presented. Products of synthesis are investigated by the methods of x-ray phase and thermal analyses, electron microscopy, and IR spectroscopy. The structure of the synthesized powder includes metal copper, Cu2O and CuO copper oxides, and hydrated copper hydroxide Cu(OH)2·N2O. Results of investigations of structural changes of the synthesized products during heating in vacuum and air are presented.

  16. Correlation Spectroscopy and Molecular Dynamics Simulations to Study the Structural Features of Proteins

    PubMed Central

    Varriale, Antonio; Marabotti, Anna; Mei, Giampiero; Staiano, Maria; D’Auria, Sabato

    2013-01-01

    In this work, we used a combination of fluorescence correlation spectroscopy (FCS) and molecular dynamics (MD) simulation methodologies to acquire structural information on pH-induced unfolding of the maltotriose-binding protein from Thermus thermophilus (MalE2). FCS has emerged as a powerful technique for characterizing the dynamics of molecules and it is, in fact, used to study molecular diffusion on timescale of microsecond and longer. Our results showed that keeping temperature constant, the protein diffusion coefficient decreased from 84±4 µm2/s to 44±3 µm2/s when pH was changed from 7.0 to 4.0. An even more marked decrease of the MalE2 diffusion coefficient (31±3 µm2/s) was registered when pH was raised from 7.0 to 10.0. According to the size of MalE2 (a monomeric protein with a molecular weight of 43 kDa) as well as of its globular native shape, the values of 44 µm2/s and 31 µm2/s could be ascribed to deformations of the protein structure, which enhances its propensity to form aggregates at extreme pH values. The obtained fluorescence correlation data, corroborated by circular dichroism, fluorescence emission and light-scattering experiments, are discussed together with the MD simulations results. PMID:23750215

  17. Frozen debris lobe morphology and movement: an overview of eight dynamic features, southern Brooks Range, Alaska

    NASA Astrophysics Data System (ADS)

    Darrow, Margaret M.; Gyswyt, Nora L.; Simpson, Jocelyn M.; Daanen, Ronald P.; Hubbard, Trent D.

    2016-05-01

    Frozen debris lobes (FDLs) are elongated, lobate permafrost features that mostly move through shear in zones near their bases. We present a comprehensive overview of eight FDLs within the Dalton Highway corridor (southern Brooks Range, Alaska), including their catchment geology and rock strengths, lobe soil characteristics, surface movement measurements collected between 2012 and 2015, and analysis of historic and modern imagery from 1955 to 2014. Field mapping and rock strength data indicate that the metasedimentary and metavolcanic bedrock forming the majority of the lobe catchments has very low to medium strength and is heavily fractured, thus easily contributing to FDL formation. The eight investigated FDLs consist of platy rocks typical of their catchments, organic debris, and an ice-poor soil matrix; massive ice, however, is present within FDLs as infiltration ice, concentrated within cracks open to the surface. Exposure of infiltration ice in retrogressive thaw slumps (RTSs) and associated debris flows leads to increased movement and various stages of destabilization, resulting in morphological differences among the lobes. Analysis of historic imagery indicates that movement of the eight investigated FDLs has been asynchronous over the study period, and since 1955, there has been an overall increase in movement rates of the investigated FDLs. The formation of surface features, such as cracks, scarps, and RTSs, suggests that the increased movement rates correlate to general instability, and even at their current distances, FDLs are impacting infrastructure through increased sediment mobilization. FDL-A is the largest of the investigated FDLs. As of August 2015, FDL-A was 39.2 m from the toe of the Dalton Highway embankment. Based on its current distance and rate of movement, we predict that FDL-A will reach the Dalton Highway alignment by 2023.

  18. Protecting Persistent Dynamic Oceanographic Features: Transboundary Conservation Efforts Are Needed for the Critically Endangered Balearic Shearwater

    PubMed Central

    Louzao, Maite; Delord, Karine; García, David; Boué, Amélie; Weimerskirch, Henri

    2012-01-01

    The protection of key areas for biodiversity at sea is not as widespread as on land and research investment is necessary to identify biodiversity hotspots in the open ocean. Spatially explicit conservation measures such as the creation of representative networks of marine protected areas (MPAs) is a critical step towards the conservation and management of marine ecosystems, as well as to improve public awareness. Conservation efforts in ecologically rich and threatened ecosystems are specially needed. This is particularly urgent for the Mediterranean marine biodiversity, which includes highly mobile marine vertebrates. Here, we studied the at sea distribution of one of the most endangered Mediterranean seabird, the critically endangered Balearic shearwater Puffinus mauretanicus. Present knowledge, from vessel-based surveys, suggests that this species has a coastal distribution over the productive Iberian shelf in relation to the distribution of their main prey, small pelagic fish. We used miniaturised satellite transmitters to determine the key marine areas of the southern population of Balearic shearwaters breeding on Eivissa and spot the spatial connections between breeding and key marine areas. Our tracking study indicates that Balearic shearwaters do not only forage along the Iberian continental shelf but also in more distant marine areas along the North African coast, in particular W of Algeria, but also NE coast of Morocco. Birds recurrently visit these shelf areas at the end of the breeding season. Species distribution modelling identified chlorophyll a as the most important environmental variable in defining those oceanographic features characterizing their key habitats in the western Mediterranean. We identified persistent oceanographic features across time series available in the study area and discuss our results within the current conservation scenario in relation to the ecology of the species. PMID:22590510

  19. Identifying dynamic features on Mars through multi-instrument co-registration of orbital images

    NASA Astrophysics Data System (ADS)

    Sidiropoulos, P.; Muller, J.-P.

    2015-10-01

    The detection and characterisation of dynamic phenomena on Mars can benefit from the systematic reconnaisance of the martian surface through highresolution orbiter imagery. The original framework implies the straightforward detection of surface changes through the comparison of multi-temporal images acquired from a single instrument. However, up until the present-day, mainly single-instrument image pairs significantly limit the time and areal coverage range on which change detection techniques can be applied. Therefore, we have developed a pipeline that performs multi-instrument co-registration of orbital images, thus allowing the automatic detection of changes in images originating from different orbiter cameras. This work summarises the developed pipeline and shows some examples of surface changes that were detected with the help of multi-instrument co-registration.

  20. Cortical pitch response components index stimulus onset/offset and dynamic features of pitch contours

    PubMed Central

    Krishnan, Ananthanarayan; Gandour, Jackson T.; Ananthakrishnan, Saradha; Vijayaraghavan, Venkatakrishnan

    2014-01-01

    Voice pitch is an important information-bearing component of language that is subject to experience dependent plasticity at both early cortical and subcortical stages of processing. We’ve already demonstrated that pitch onset component (Na) of the cortical pitch response (CPR) is sensitive to flat pitch and its salience. In regards to dynamic pitch, we do not yet know whether the multiple pitch-related transient components of the CPR reflect specific temporal attributes of such stimuli. Here we examine the sensitivity of the multiple transient components of CPR to changes in pitch acceleration associated with the Mandarin high rising lexical tone. CPR responses from Chinese listeners were elicited by three citation forms varying in pitch acceleration and duration. Results showed that the pitch onset component (Na) was invariant to changes in acceleration. In contrast, Na-Pb and Pb-Nb showed a systematic increase in the interpeak latency and decrease in amplitude with increase in pitch acceleration that followed the time course of pitch change across the three stimuli. A strong correlation with pitch acceleration was observed for these two components only – a putative index of pitch-relevant neural activity associated with the more rapidly-changing portions of the pitch contour. Pc-Nc marks unambiguously the stimulus offset. We therefore propose that in the early stages of cortical sensory processing, a series of neural markers flag different temporal attributes of a dynamic pitch contour: onset of temporal regularity (Na); changes in temporal regularity between onset and offset (Na-Pb, Pb-Nb); and offset of temporal regularity (Pc-Nc). At the temporal electrode sites, the stimulus with the most gradual change in pitch acceleration evoked a rightward asymmetry. Yet within the left hemisphere, stimuli with more gradual change were indistinguishable. These findings highlight the emergence of early hemispheric preferences and their functional roles as related to

  1. Mapping and Monitoring of Dynamic Seafloor Features with Hydroacoustic Devices in Sandy Coastal Areas (German Bight, North Sea)

    NASA Astrophysics Data System (ADS)

    Papenmeier, S.; Mielck, F.; Hass, H. C.

    2014-12-01

    In order to understand marine ecosystems and to provide basic data for a sustainable management in these vulnerable areas, seafloor mapping has become increasingly important. Since the knowledge regarding the seabed environments and their dynamics are still sparse, new mapping techniques have evolved in the last years and hydroacoustic devices became an important tool for quick and reliable mapping. In 2007 we started a monitoring program in the German Bight (North Sea) using sidescan sonar (Imagenex YellowFin, 330 kHz) in a study site comprising approximately 1,500 km2. In subsequent years, the area was mapped repeatedly with a resolution of ~25 cm. For ground truthing, several hundred sediment samples were taken. The investigations reveal that the area is mainly characterized by fine to coarse sand which is arranged in different seafloor features such as subaquatic dunes or relicts of Pleistocene moraines. While the alignment and position of the moraines was stable throughout the years, the dunes can be highly dynamic. Their migration indicates the amount of sediment transport in these areas. Some seafloor features could be identified as so-called sorted bedforms, which are spatially-grain-size-sorted patterns on the seafloor consisting of small rippled medium sand surrounded by smooth fine sand. These flow-transverse features are morphological linked to ridges and depressions and are further maintained by ebb and flood currents of almost equal strengths. The medium sand is separated from the fine sand by sharp boundaries in all directions which were generated by the bidirectional flow field. The extend and alignment of the sorted bedforms seem to be relatively stable in a time frame of 6 years, however small-scale variabilities up to serveral meters could be detected. We suppose that these processes mainly occur during storm surges while the fine-sand layers are winnowed away and hence the shapes of the bedforms changes.

  2. An efficient overset grid technique for computational fluid dynamics based on method coupling and feature tracking

    NASA Astrophysics Data System (ADS)

    Snyder, Richard Dean

    A new overset grid method that permits different fluid models to be coupled in a single simulation is presented. High fidelity methods applied in regions of complex fluid flow can be coupled with simpler methods to save computer simulation time without sacrificing accuracy. A mechanism for automatically moving grid zones to track unsteady flow features complements the method. The coupling method is quite general and will support a variety of governing equations and discretization methods. Furthermore, there are no restrictions on the geometrical layout of the coupling. Four sets of governing equations have been implemented to date: the Navier-Stokes, full Euler, Cartesian Euler, and linearized Euler equations. In all cases, the MacCormack explicit predictor-corrector scheme was used to discretize the equations. The overset coupling technique was applied to a variety of configurations in one, two, and three dimensions. Steady configurations include the flow over a bump, a NACA0012 airfoil, and an F-5 wing. Unsteady configurations include two aeroacoustic benchmark problems and a NACA64A006 airfoil with an oscillating simple flap. Solutions obtained with the overset coupling method are compared with other numerical results and, when available, with experimental data. Results from the NACA0012 airfoil and F-5 wing show a 30% reduction in simulation time without a loss of accuracy when the linearized Euler equations were coupled with the full Euler equations. A 25% reduction was recorded for the NACA0012 airfoil when the Euler equations were solved together with the Navier-Stokes equations. Feature tracking was used in the aeroacoustic benchmark and NACA64A006 problems and was found to be very effective in minimizing the dispersion error in the vicinity of shocks. The computer program developed to implement the overset grid method coupling technique was written entirely in C++, an object-oriented programming language. The principles of object-oriented programming were

  3. Ultrafast transient absorption revisited: Phase-flips, spectral fingers, and other dynamical features.

    PubMed

    Cina, Jeffrey A; Kovac, Philip A; Jumper, Chanelle C; Dean, Jacob C; Scholes, Gregory D

    2016-05-01

    We rebuild the theory of ultrafast transient-absorption/transmission spectroscopy starting from the optical response of an individual molecule to incident femtosecond pump and probe pulses. The resulting description makes use of pulse propagators and free molecular evolution operators to arrive at compact expressions for the several contributions to a transient-absorption signal. In this alternative description, which is physically equivalent to the conventional response-function formalism, these signal contributions are conveniently expressed as quantum mechanical overlaps between nuclear wave packets that have undergone different sequences of pulse-driven optical transitions and time-evolution on different electronic potential-energy surfaces. Using this setup in application to a simple, multimode model of the light-harvesting chromophores of PC577, we develop wave-packet pictures of certain generic features of ultrafast transient-absorption signals related to the probed-frequency dependence of vibrational quantum beats. These include a Stokes-shifting node at the time-evolving peak emission frequency, antiphasing between vibrational oscillations on opposite sides (i.e., to the red or blue) of this node, and spectral fingering due to vibrational overtones and combinations. Our calculations make a vibrationally abrupt approximation for the incident pump and probe pulses, but properly account for temporal pulse overlap and signal turn-on, rather than neglecting pulse overlap or assuming delta-function excitations, as are sometimes done. PMID:27155654

  4. Ultrafast transient absorption revisited: Phase-flips, spectral fingers, and other dynamical features

    NASA Astrophysics Data System (ADS)

    Cina, Jeffrey A.; Kovac, Philip A.; Jumper, Chanelle C.; Dean, Jacob C.; Scholes, Gregory D.

    2016-05-01

    We rebuild the theory of ultrafast transient-absorption/transmission spectroscopy starting from the optical response of an individual molecule to incident femtosecond pump and probe pulses. The resulting description makes use of pulse propagators and free molecular evolution operators to arrive at compact expressions for the several contributions to a transient-absorption signal. In this alternative description, which is physically equivalent to the conventional response-function formalism, these signal contributions are conveniently expressed as quantum mechanical overlaps between nuclear wave packets that have undergone different sequences of pulse-driven optical transitions and time-evolution on different electronic potential-energy surfaces. Using this setup in application to a simple, multimode model of the light-harvesting chromophores of PC577, we develop wave-packet pictures of certain generic features of ultrafast transient-absorption signals related to the probed-frequency dependence of vibrational quantum beats. These include a Stokes-shifting node at the time-evolving peak emission frequency, antiphasing between vibrational oscillations on opposite sides (i.e., to the red or blue) of this node, and spectral fingering due to vibrational overtones and combinations. Our calculations make a vibrationally abrupt approximation for the incident pump and probe pulses, but properly account for temporal pulse overlap and signal turn-on, rather than neglecting pulse overlap or assuming delta-function excitations, as are sometimes done.

  5. Swine manure vermicomposting via housefly larvae (Musca domestica): the dynamics of biochemical and microbial features.

    PubMed

    Zhang, ZhiJian; Wang, Hang; Zhu, Jun; Suneethi, Sundar; Zheng, JianGuo

    2012-08-01

    Improper handling of animal manure generated from concentrated swine operations greatly deteriorates water ecosystems. In this study, a full-scale vermireactor using housefly larvae (Musca domestica) was designed to investigate the effectiveness and efficiency of swine manure reduction, and to explore the associated biochemical-biological mechanisms. The one-week larvae vermireactor resulted in a total weight reduction rate of 106±17 kg/(m(3) d) and moisture reduction of 80.2%. Microbial activities in manure decreased by 45% after vermicomposting, while the activities of cellulose, proteases, and phosphatases in the vermicompost were significantly 69 times, 48%, and 82% lower than those in raw manure, respectively. The vermicompost was exclusively dominated by Entomoplasma somnilux, Proteobacterium, and Clostridiaceae bacterium where the microbial diversity was decreased from 2.57 in raw manure to 1.77. Correlation coefficients statistic showed that organic C might be a key indicator of the biochemical features and microbial functions of the larvae vermireactor. PMID:22728759

  6. Connections between structural jamming, local metabasin features, and relaxation dynamics in a supercooled glassy liquid

    NASA Astrophysics Data System (ADS)

    Frechero, M. A.; Alarcón, L. M.; Schulz, E. P.; Appignanesi, G. A.

    2007-01-01

    Dynamics in glass-forming liquids in the supercooled regime vary considerably from one point of the sample to another suggesting the existence of regions with different degrees of jamming. In fact, the existence of relatively compact regions with particles with an enhanced propensity for motion has been detected in model glassy systems. In turn, the structural relaxation has been shown to be accomplished by means of a series of fast transitions between metabasins in the potential energy landscape involving the collective motion of a substantial number of particles arranged in relatively compact clusters (democratic clusters or d clusters). In this work we shall complete this picture by identifying the connections between local structural jamming, metabasin confining strength, and d clusters. Thus we shall demonstrate that the degree of jamming of the local structure dictates the confining strength of the local metabasin and that the local high propensity regions and the d clusters are not only similar in nature but that they share a significant amount of particles.

  7. Features of exciton dynamics in molecular nanoclusters (J-aggregates): Exciton self-trapping (Review Article)

    NASA Astrophysics Data System (ADS)

    Malyukin, Yu. V.; Sorokin, A. V.; Semynozhenko, V. P.

    2016-06-01

    We present thoroughly analyzed experimental results that demonstrate the anomalous manifestation of the exciton self-trapping effect, which is already well-known in bulk crystals, in ordered molecular nanoclusters called J-aggregates. Weakly-coupled one-dimensional (1D) molecular chains are the main structural feature of J-aggregates, wherein the electron excitations are manifested as 1D Frenkel excitons. According to the continuum theory of Rashba-Toyozawa, J-aggregates can have only self-trapped excitons, because 1D excitons must adhere to barrier-free self-trapping at any exciton-phonon coupling constant g = ɛLR/2β, wherein ɛLR is the lattice relaxation energy, and 2β is the half-width of the exciton band. In contrast, very often only the luminescence of free, mobile excitons would manifest in experiments involving J-aggregates. Using the Urbach rule in order to analyze the low-frequency region of the low-temperature exciton absorption spectra has shown that J-aggregates can have both a weak (g < 1) and a strong (g > 1) exciton-phonon coupling. Moreover, it is experimentally demonstrated that under certain conditions, the J-aggregate excited state can have both free and self-trapped excitons, i.e., we establish the existence of a self-trapping barrier for 1D Frenkel excitons. We demonstrate and analyze the reasons behind the anomalous existence of both free and self-trapped excitons in J-aggregates, and demonstrate how exciton-self trapping efficiency can be managed in J-aggregates by varying the values of g, which is fundamentally impossible in bulk crystals. We discuss how the exciton-self trapping phenomenon can be used as an alternate interpretation of the wide band emission of some J-aggregates, which has thus far been explained by the strongly localized exciton model.

  8. Ionospheric plasma dynamics and instability caused by upward currents above thunderstorms

    NASA Astrophysics Data System (ADS)

    Kuo, C. L.; Lee, L. C.

    2015-04-01

    Thunderstorms are electric generators, which drive currents upwardly into the ionosphere. In this paper, we examine the effects of thunderstorm upward current on the ionosphere. We use a thunderstorm model to calculate the three-dimensional current flows in the atmosphere and to simulate the upward current above the thunderstorm with the tripole-charge structure. The upward current flows into the ionosphere, while the associated electric field causes the plasma E × B motion. The caused plasma motion redistributes the plasma density, leading to ionospheric density variations. In the nighttime ionosphere, the E × B motion may also cause the formation of plasma bubbles.

  9. De Novo Mutations of RERE Cause a Genetic Syndrome with Features that Overlap Those Associated with Proximal 1p36 Deletions.

    PubMed

    Fregeau, Brieana; Kim, Bum Jun; Hernández-García, Andrés; Jordan, Valerie K; Cho, Megan T; Schnur, Rhonda E; Monaghan, Kristin G; Juusola, Jane; Rosenfeld, Jill A; Bhoj, Elizabeth; Zackai, Elaine H; Sacharow, Stephanie; Barañano, Kristin; Bosch, Daniëlle G M; de Vries, Bert B A; Lindstrom, Kristin; Schroeder, Audrey; James, Philip; Kulch, Peggy; Lalani, Seema R; van Haelst, Mieke M; van Gassen, Koen L I; van Binsbergen, Ellen; Barkovich, A James; Scott, Daryl A; Sherr, Elliott H

    2016-05-01

    Deletions of chromosome 1p36 affect approximately 1 in 5,000 newborns and are associated with developmental delay, intellectual disability, and defects involving the brain, eye, ear, heart, and kidney. Arginine-glutamic acid dipeptide repeats (RERE) is located in the proximal 1p36 critical region. RERE is a widely-expressed nuclear receptor coregulator that positively regulates retinoic acid signaling. Animal models suggest that RERE deficiency might contribute to many of the structural and developmental birth defects and medical problems seen in individuals with 1p36 deletion syndrome, although human evidence supporting this role has been lacking. In this report, we describe ten individuals with intellectual disability, developmental delay, and/or autism spectrum disorder who carry rare and putatively damaging changes in RERE. In all cases in which both parental DNA samples were available, these changes were found to be de novo. Associated features that were recurrently seen in these individuals included hypotonia, seizures, behavioral problems, structural CNS anomalies, ophthalmologic anomalies, congenital heart defects, and genitourinary abnormalities. The spectrum of defects documented in these individuals is similar to that of a cohort of 31 individuals with isolated 1p36 deletions that include RERE and are recapitulated in RERE-deficient zebrafish and mice. Taken together, our findings suggest that mutations in RERE cause a genetic syndrome and that haploinsufficiency of RERE might be sufficient to cause many of the phenotypes associated with proximal 1p36 deletions. PMID:27087320

  10. Study on dynamic characteristics' change of hippocampal neuron reduced models caused by the Alzheimer's disease.

    PubMed

    Peng, Yueping; Wang, Jue; Zheng, Chongxun

    2016-01-01

    In the paper, based on the electrophysiological experimental data, the Hippocampal neuron reduced model under the pathology condition of Alzheimer's disease (AD) has been built by modifying parameters' values. The reduced neuron model's dynamic characteristics under effect of AD are comparatively studied. Under direct current stimulation, compared with the normal neuron model, the AD neuron model's dynamic characteristics have obviously been changed. The neuron model under the AD condition undergoes supercritical Andronov-Hopf bifurcation from the rest state to the continuous discharge state. It is different from the neuron model under the normal condition, which undergoes saddle-node bifurcation. So, the neuron model changes into a resonator with monostable state from an integrator with bistable state under AD's action. The research reveals the neuron model's dynamic characteristics' changing under effect of AD, and provides some theoretic basis for AD research by neurodynamics theory. PMID:26998957

  11. Optimization of a 3D Dynamic Culturing System for In Vitro Modeling of Frontotemporal Neurodegeneration-Relevant Pathologic Features

    PubMed Central

    Tunesi, Marta; Fusco, Federica; Fiordaliso, Fabio; Corbelli, Alessandro; Biella, Gloria; Raimondi, Manuela T.

    2016-01-01

    Frontotemporal lobar degeneration (FTLD) is a severe neurodegenerative disorder that is diagnosed with increasing frequency in clinical setting. Currently, no therapy is available and in addition the molecular basis of the disease are far from being elucidated. Consequently, it is of pivotal importance to develop reliable and cost-effective in vitro models for basic research purposes and drug screening. To this respect, recent results in the field of Alzheimer’s disease have suggested that a tridimensional (3D) environment is an added value to better model key pathologic features of the disease. Here, we have tried to add complexity to the 3D cell culturing concept by using a microfluidic bioreactor, where cells are cultured under a continuous flow of medium, thus mimicking the interstitial fluid movement that actually perfuses the body tissues, including the brain. We have implemented this model using a neuronal-like cell line (SH-SY5Y), a widely exploited cell model for neurodegenerative disorders that shows some basic features relevant for FTLD modeling, such as the release of the FTLD-related protein progranulin (PRGN) in specific vesicles (exosomes). We have efficiently seeded the cells on 3D scaffolds, optimized a disease-relevant oxidative stress experiment (by targeting mitochondrial function that is one of the possible FTLD-involved pathological mechanisms) and evaluated cell metabolic activity in dynamic culture in comparison to static conditions, finding that SH-SY5Y cells cultured in 3D scaffold are susceptible to the oxidative damage triggered by a mitochondrial-targeting toxin (6-OHDA) and that the same cells cultured in dynamic conditions kept their basic capacity to secrete PRGN in exosomes once recovered from the bioreactor and plated in standard 2D conditions. We think that a further improvement of our microfluidic system may help in providing a full device where assessing basic FTLD-related features (including PRGN dynamic secretion) that may

  12. Outcome Prediction for Patients with Traumatic Brain Injury with Dynamic Features from Intracranial Pressure and Arterial Blood Pressure Signals: A Gaussian Process Approach.

    PubMed

    Pimentel, Marco A F; Brennan, Thomas; Lehman, Li-Wei; King, Nicolas Kon Kam; Ang, Beng-Ti; Feng, Mengling

    2016-01-01

    Previous work has been demonstrated that tracking features describing the dynamic and time-varying patterns in brain monitoring signals provide additional predictive information beyond that derived from static features based on snapshot measurements. To achieve more accurate predictions of outcomes of patients with traumatic brain injury (TBI), we proposed a statistical framework to extract dynamic features from brain monitoring signals based on the framework of Gaussian processes (GPs). GPs provide an explicit probabilistic, nonparametric Bayesian approach to metric regression problems. This not only provides probabilistic predictions, but also gives the ability to cope with missing data and infer model parameters such as those that control the function's shape, noise level and dynamics of the signal. Through experimental evaluation, we have demonstrated that dynamic features extracted from GPs provide additional predictive information in addition to the features based on the pressure reactivity index (PRx). Significant improvements in patient outcome prediction were achieved by combining GP-based and PRx-based dynamic features. In particular, compared with the a baseline PRx-based model, the combined model achieved over 30 % improvement in prediction accuracy and sensitivity and over 20 % improvement in specificity and the area under the receiver operating characteristic curve. PMID:27165883

  13. Association between dynamic contrast enhanced MRI imaging features and WHO histopathological grade in patients with invasive ductal breast cancer

    PubMed Central

    HUANG, JUAN; YU, JIANQUN; PENG, YULAN

    2016-01-01

    The present study aimed to investigate the dynamic contrast enhanced magnetic resonance imaging (DCE-MRI) and World Health Organization (WHO) histopathological grade in patients with invasive ductal breast cancer. A retrospective analysis on the results of DCE-MRI of 92 patients, who were diagnosed with invasive ductal breast cancer following surgery or biopsy, and these results were correlated with WHO histopathological grade. The statistical analysis demonstrated that the tumor size, shape and characteristics of early enhancement were associated with the WHO histopathological grade: The larger the lesion's long diameter, the higher the WHO histopathological grade; the WHO histopathological grades of round and oval masses were relatively lower, while those of lobulated and irregular masses were higher; and tumors with heterogeneous and ring-like enhancement exhibited higher WHO histopathological grades, while those of homogeneous enhancement were lower. The lesion's margin shape was not associated with the WHO histopathological grade. The present study demonstrates that features of DCE-MRI and WHO histopathological grade in patients with invasive ductal breast cancer are correlated, and these MRI features could be used to evaluate the biological behavior and prognosis of lesions. PMID:27123145

  14. Coinciding Features in a Turbulent Boundary Layer via Lagrangian Coherent Structures, Dynamic Mode Decomposition and Proper Orthogonal Decomposition

    NASA Astrophysics Data System (ADS)

    Ali, Naseem; Tutkun, Murat; Cal, Rau'l.

    2015-11-01

    Low order decompositions and Lagrangian coherent structures are used to identify structures in a high-Reynolds-number turbulent boundary layer flow. Data are collected in Laboratoire de Mécanique de Lille (LML) wind tunnel using time resolved stereo particle image velocimetry. Low-order descriptors are based on proper orthogonal decomposition (POD) and dynamic mode decomposition (DMD) frameworks to obtain energy content and frequency information of the flow, respectively. Repelling and attracting Lagrangian coherent structures (LCS)s reveal complex patterns within the flow field containing a hyperbolic behavior and the shapes of the attracting and repelling vary with advection time as result of the temporal coherence. The attracting and repelling LCSs are matched with POD and DMD modes to understand the relationship between the frameworks and respective representations. The POD is used as a low pass filtering of kinetic energy and then mode-dependent velocity reconstructions provide, firstly, the most coherent features of the flow and second are employed to generate new mode-based LCSs. This representations then provide clarity as to the organization of the LCS based on the energy contained in them and the dynamic coherence.

  15. BEEHAVE: a systems model of honeybee colony dynamics and foraging to explore multifactorial causes of colony failure

    PubMed Central

    Becher, Matthias A; Grimm, Volker; Thorbek, Pernille; Horn, Juliane; Kennedy, Peter J; Osborne, Juliet L

    2014-01-01

    A notable increase in failure of managed European honeybee Apis mellifera L. colonies has been reported in various regions in recent years. Although the underlying causes remain unclear, it is likely that a combination of stressors act together, particularly varroa mites and other pathogens, forage availability and potentially pesticides. It is experimentally challenging to address causality at the colony scale when multiple factors interact. In silico experiments offer a fast and cost-effective way to begin to address these challenges and inform experiments. However, none of the published bee models combine colony dynamics with foraging patterns and varroa dynamics. We have developed a honeybee model, BEEHAVE, which integrates colony dynamics, population dynamics of the varroa mite, epidemiology of varroa-transmitted viruses and allows foragers in an agent-based foraging model to collect food from a representation of a spatially explicit landscape. We describe the model, which is freely available online (www.beehave-model.net). Extensive sensitivity analyses and tests illustrate the model's robustness and realism. Simulation experiments with various combinations of stressors demonstrate, in simplified landscape settings, the model's potential: predicting colony dynamics and potential losses with and without varroa mites under different foraging conditions and under pesticide application. We also show how mitigation measures can be tested. Synthesis and applications. BEEHAVE offers a valuable tool for researchers to design and focus field experiments, for regulators to explore the relative importance of stressors to devise management and policy advice and for beekeepers to understand and predict varroa dynamics and effects of management interventions. We expect that scientists and stakeholders will find a variety of applications for BEEHAVE, stimulating further model development and the possible inclusion of other stressors of potential importance to honeybee

  16. Control of electron spin decoherence caused by electron nuclear spin dynamics in a quantum dot

    NASA Astrophysics Data System (ADS)

    Liu, Ren-Bao; Yao, Wang; Sham, L. J.

    2007-07-01

    Control of electron spin decoherence in contact with a mesoscopic bath of many interacting nuclear spins in an InAs quantum dot is studied by solving the coupled quantum dynamics. The nuclear spin bath, because of its bifurcated evolution predicated on the electron spin up or down state, measures the which-state information of the electron spin and hence diminishes its coherence. The many-body dynamics of the nuclear spin bath is solved with a pair-correlation approximation. In the relevant timescale, nuclear pair-wise flip flops, as elementary excitations in the mesoscopic bath, can be mapped into the precession of non-interacting pseudo-spins. Such mapping provides a geometrical picture for understanding the decoherence and for devising control schemes. A close examination of nuclear bath dynamics reveals a wealth of phenomena and new possibilities of controlling the electron spin decoherence. For example, when the electron spin is flipped by a π-pulse at τ, its coherence will partially recover at \\sqrt{2}\\tau as a consequence of quantum disentanglement from the mesoscopic bath. In contrast to the re-focusing of inhomogeneously broadened phases by conventional spin-echoes, the disentanglement is realized through shepherding quantum evolution of the bath state via control of the quantum object. A concatenated construction of pulse sequences can eliminate the decoherence with arbitrary accuracy, with the nuclear nuclear spin interaction strength acting as the controlling small parameter.

  17. The transition zone chlorophyll front, a dynamic global feature defining migration and forage habitat for marine resources

    NASA Astrophysics Data System (ADS)

    Polovina, Jeffrey J.; Howell, Evan; Kobayashi, Donald R.; Seki, Michael P.

    Pelagic ecosystem dynamics on all temporal scales may be driven by the dynamics of very specialized oceanic habitats. One such habitat is the basin-wide chlorophyll front located at the boundary between the low chlorophyll subtropical gyres and the high chlorophyll subarctic gyres. Global satellite maps of surface chlorophyll clearly show this feature in all oceans. In the North Pacific, the front is over 8000 km long and seasonally migrates north and south about 1000 km. In the winter this front is located at about 30-35°N latitude and in the summer at about 40-45°N. It is a zone of surface convergence where cool, vertically mixed, high chlorophyll, surface water on the north side sinks beneath warm, stratified, low chlorophyll water on the south side. Satellite telemetry data on movements of loggerhead turtles and detailed fisheries data for albacore tuna show that both apex predators travel along this front as they migrate across the North Pacific. The front is easily monitored with ocean color satellite remote sensing. A change in the position of the TZCF between 1997 and 1998 appears to have altered the spatial distribution of loggerhead turtles. The position and dynamics of the front varied substantially between the 1998 El Niño and the 1999 La Niña. For example, from May to July 1999 the transition zone chlorophyll front (TZCF) remained between about 35°N and 40°N latitude showing very little meandering, whereas in 1998, during the same period, the TZCF exhibited considerable meandering and greater monthly latitudinal movement. Catch rates for albacore were considerably higher in 1998 than in 1999, and we hypothesize that a meandering TZCF creates regions of convergence, which enhances the foraging habitat for apex predators along the front.

  18. Volcanic-sedimentary features in the Serra Geral Fm., Paraná Basin, southern Brazil: Examples of dynamic lava-sediment interactions in an arid setting

    NASA Astrophysics Data System (ADS)

    Petry, Karla; Jerram, Dougal A.; de Almeida, Delia del Pilar M.; Zerfass, Henrique

    2007-01-01

    The formation of volcanic-sedimentary interaction features in extreme arid environments is not a commonly described process. Specifically the occurrence of dynamically mixed sediments and juvenile igneous clasts as peperites, for water has been considered one major important factor in the processes of magma dismantling and mingling with unconsolidated sediment to form such deposits. The study area, located in south Brazil, shows a sequence of lava flows and intertrapic sandstone layers from the Paraná Basin, associated with the formation of clastic dykes, flow striations, peperite and 'peperite-like' breccias. Four processes are suggested for the genesis of the peperites: (a) fragmentation of the flow front and base; (b) sand injection; (c) dune collapse; (d) magma cascade downhill. The continued flow of a lava, while its outer crust is already cooling, causes it to break, especially in the front and base, fragments falling in the sand and getting mixed with it, generating the flow front 'peperite-like' breccia. The weight of the lava flow associated to shear stress at the base cause sand to be injected inwards the flow, forming injection clastic dykes in the cooled parts and injection peperite in the more plastic portions. The lava flow may partially erode the dune, causing the dune to collapse and forming the collapse 'peperite-like' breccia. The shear stress at the base of a flowing lava striates the unconsolidated sand, forming the flow striations. The sand that migrates over a cooled, jointed lava flow may get caught in the cavities and joints, forming the filling clastic dykes. These deposits are analogous to those found in the Etendeka, NW Namibia, and show that sediment-lava interactions in arid settings are widespread throughout the Paraná-Etendeka province during the onset of flood volcanism.

  19. Hereditary nonspherocytic hemolytic anemia caused by red cell glucose-6-phosphate isomerase (GPI) deficiency in two Portuguese patients: Clinical features and molecular study.

    PubMed

    Manco, Licínio; Bento, Celeste; Victor, Bruno L; Pereira, Janet; Relvas, Luís; Brito, Rui M; Seabra, Carlos; Maia, Tabita M; Ribeiro, M Letícia

    2016-09-01

    Glucose-6-phosphate isomerase (GPI) deficiency cause hereditary nonspherocytic hemolytic anemia (HNSHA) of variable severity in individuals homozygous or compound heterozygous for mutations in GPI gene. This work presents clinical features and genotypic results of two patients of Portuguese origin with GPI deficiency. The patients suffer from a mild hemolytic anemia (Hb levels ranging from 10 to 12.7g/mL) associated with macrocytosis, reticulocytosis, hyperbilirubinemia, hyperferritinemia and slight splenomegaly. Genomic DNA sequencing revealed in one patient homozygosity for a new missense mutation in exon 3, c.260G>C (p.Gly87Ala), and in the second patient compound heterozygosity for the same missense mutation (p.Gly87Ala), along with a frameshift mutation resulting from a single nucleotide deletion in exon 14, c.1238delA (p.Gln413Arg fs*24). Mutation p.Gln413Arg fs*24 is the first frameshift null mutation to be described in GPI deficiency. Molecular modeling suggests that the structural change induced by the p.Gly87Ala pathogenic variant has direct impact in the structural arrangement of the region close to the active site of the enzyme. PMID:27519939

  20. Features of the short-term position variation of the west Pacific subtropical high during the torrential rain in Yangtze-Huaihe river valley and its possible cause

    NASA Astrophysics Data System (ADS)

    Guan, Zhaoyong; Yu, Bo; Wang, Lijuan; He, Jielin; Zeng, Gang

    2009-08-01

    By using the NCEP/NCAR daily reanalysis data, CMAP precipitation data , daily precipitation data of 740 stations in China and some remote sensing data, features of the short-term position variation of the west Pacific subtropical high(WPSH) during the torrential rain in Yangtze-Huaihe river valley and its possible cause are analyzed. Results show that the short-term position variation of WPSH is closely associated with the diabatic heating. During the torrential rain period, the apparent heating source and apparent moisture sink are exceptionally strong over Yangtze-Huaihe river valley( on the northwest side of WPSH )and the Bay of Bengal (to the west of WPSH). Based on the complete form of vertical vorticity tendency equation, it is found that the heating field over Yangtze-Huaihe river valley during the torrential rain period, which is in favor of the increase of cyclonic vorticity on the north side of WPSH, is unfavorable to the WPSH moving northward. And the heat source over the Bay of Bengal ,which is in favor of the increase of anti-cyclonic vorticity on the west of WPSH, may induce the westward extension of WPSH.

  1. Dramatic changes of optical nonlinearity and ultrafast dynamics of palladium nanoparticles caused by hydriding

    NASA Astrophysics Data System (ADS)

    Fan, Guanghua; Chen, Minrui; Wu, Xingzhi; Han, Min; Song, Yinglin; Qu, Shiliang; Xie, Bo; Yang, Linpo; Gao, Renxi; Guo, Zhongyi; Liu, Jiaqi

    2016-01-01

    Pd nanoparticles are deposited on one surface of a quartz sheet. Their optical nonlinearity and ultrafast dynamics in air and in hydrogen environment are investigated. The Pd nanoparticles exhibit self focusing and saturable absorption in air. In hydrogen environment with increasing hydrogen, the NPs maintain self focusing, however their nonlinear refraction index increases; and their nonlinear absorption changes from saturable absorption to reverse saturable absorption. In hydrogen environment, the acoustic breathing movement of these NPs damps more obviously and the contact between the NPs and quartz sheet is looser, comparing to that in air.

  2. Theoretical calculations and experimental verification for the pumping effect caused by the dynamic micro-tapered angle

    NASA Astrophysics Data System (ADS)

    Cai, Yufei; Zhang, Jianhui; Zhu, Chunling; Huang, Jun; Jiang, Feng

    2016-05-01

    The atomizer with micro cone apertures has advantages of ultra-fine atomized droplets, low power consumption and low temperature rise. The current research of this kind of atomizer mainly focuses on the performance and its application while there is less research of the principle of the atomization. Under the analysis of the dispenser and its micro-tapered aperture's deformation, the volume changes during the deformation and vibration of the micro-tapered aperture on the dispenser are calculated by coordinate transformation. Based on the characters of the flow resistance in a cone aperture, it is found that the dynamic cone angle results from periodical changes of the volume of the micro-tapered aperture of the atomizer and this change drives one-way flows. Besides, an experimental atomization platform is established to measure the atomization rates with different resonance frequencies of the cone aperture atomizer. The atomization performances of cone aperture and straight aperture atomizers are also measured. The experimental results show the existence of the pumping effect of the dynamic tapered angle. This effect is usually observed in industries that require low dispersion and micro- and nanoscale grain sizes, such as during production of high-pressure nozzles and inhalation therapy. Strategies to minimize the pumping effect of the dynamic cone angle or improve future designs are important concerns. This research proposes that dynamic micro-tapered angle is an important cause of atomization of the atomizer with micro cone apertures.

  3. Pharmacophore modeling and molecular dynamics simulation to identify the critical chemical features against human sirtuin 2 inhibitors

    NASA Astrophysics Data System (ADS)

    Sakkiah, Sugunadevi; Baek, Ayoung; Lee, Keun Woo

    2012-03-01

    Sirtuin 2 (SIRT2) is one of the emerging targets in chemotherapy field and mainly associated with many diseases such as cancer and Parkinson's. Hence, quantitative hypothesis was developed using Discovery Studio v2.5. Top ten resultant hypotheses were generated, among them Hypo1 was selected as a best hypothesis based on the statistical parameters like high cost difference (52), lowest RMS (0.71), and good correlation coefficient (0.96). Hypo1 has been validated by using well known methodologies such as Fischer's randomization method (95% confidence level), test set which has shown the correlation coefficient of 0.93 as well as the goodness of hit (0.65), and enrichment factor (8.80). All the above statistical validations confirm that the chemical features in Hypo1 (1 hydrogen bond acceptor, 1 hydrophobic, and 2 ring aromatic features) was able to inhibit the function of SIRT2. Hence, Hypo1 was used as a query in virtual screening to find a novel scaffolds by screening the various chemical databases. The screened molecules from the databases were checked for the ADMET as well as the drug-like properties. Due to the lack of SIRT2-ligand complex structure in PDB, molecular docking and molecular dynamics (MD) simulation was carried out to find the suitable orientation of ligand in the active site. The representative structure from MD simulations was used as a receptor to dock the molecules which passed the drug-like properties from the virtual screening. Finally, 29 compounds were selected as a potent candidate leads based on the interactions with the active site residues of SIRT2. Thus, the resultant pharmacophore can be used to discover and design the SIRT2 inhibitors with desired biological activity.

  4. Spatio-temporal dynamics and laterality effects of face inversion, feature presence and configuration, and face outline

    PubMed Central

    Marinkovic, Ksenija; Courtney, Maureen G.; Witzel, Thomas; Dale, Anders M.; Halgren, Eric

    2014-01-01

    Although a crucial role of the fusiform gyrus (FG) in face processing has been demonstrated with a variety of methods, converging evidence suggests that face processing involves an interactive and overlapping processing cascade in distributed brain areas. Here we examine the spatio-temporal stages and their functional tuning to face inversion, presence and configuration of inner features, and face contour in healthy subjects during passive viewing. Anatomically-constrained magnetoencephalography (aMEG) combines high-density whole-head MEG recordings and distributed source modeling with high-resolution structural MRI. Each person's reconstructed cortical surface served to constrain noise-normalized minimum norm inverse source estimates. The earliest activity was estimated to the occipital cortex at ~100 ms after stimulus onset and was sensitive to an initial coarse level visual analysis. Activity in the right-lateralized ventral temporal area (inclusive of the FG) peaked at ~160 ms and was largest to inverted faces. Images containing facial features in the veridical and rearranged configuration irrespective of the facial outline elicited intermediate level activity. The M160 stage may provide structural representations necessary for downstream distributed areas to process identity and emotional expression. However, inverted faces additionally engaged the left ventral temporal area at ~180 ms and were uniquely subserved by bilateral processing. This observation is consistent with the dual route model and spared processing of inverted faces in prosopagnosia. The subsequent deflection, peaking at ~240 ms in the anterior temporal areas bilaterally, was largest to normal, upright faces. It may reflect initial engagement of the distributed network subserving individuation and familiarity. These results support dynamic models suggesting that processing of unfamiliar faces in the absence of a cognitive task is subserved by a distributed and interactive neural circuit. PMID

  5. Determinants of extinction-colonization dynamics in Mediterranean butterflies: the role of landscape, climate and local habitat features.

    PubMed

    Fernández-Chacón, Albert; Stefanescu, Constantí; Genovart, Meritxell; Nichols, James D; Hines, James E; Páramo, Ferran; Turco, Marco; Oro, Daniel

    2014-01-01

    Many species are found today in the form of fragmented populations occupying patches of remnant habitat in human-altered landscapes. The persistence of these population networks requires a balance between extinction and colonization events assumed to be primarily related to patch area and isolation, but the contribution of factors such as the characteristics of patch and matrix habitats, the species' traits (habitat specialization and dispersal capabilities) and variation in climatic conditions have seldom been evaluated simultaneously. The identification of environmental variables associated with patch occupancy and turnover may be especially useful to enhance the persistence of multiple species under current global change. However, for robust inference on occupancy and related parameters, we must account for detection errors, a commonly overlooked problem that leads to biased estimates and misleading conclusions about population dynamics. Here, we provide direct empirical evidence of the effects of different environmental variables on the extinction and colonization rates of a rich butterfly community in the western Mediterranean. The analysis was based on a 17-year data set containing detection/nondetection data on 73 butterfly species for 26 sites in north-eastern Spain. Using multiseason occupancy models, which take into account species' detectability, we were able to obtain robust estimates of local extinction and colonization probabilities for each species and test the potential effects of site covariates such as the area of suitable habitat, topographic variability, landscape permeability around the site and climatic variability in aridity conditions. Results revealed a general pattern across species with local habitat composition and landscape features as stronger predictors of occupancy dynamics compared with topography and local aridity. Increasing area of suitable habitat in a site strongly decreased local extinction risks and, for a number of species

  6. Diseases and Causes of Death in European Bats: Dynamics in Disease Susceptibility and Infection Rates

    PubMed Central

    Mühldorfer, Kristin; Speck, Stephanie; Kurth, Andreas; Lesnik, René; Freuling, Conrad; Müller, Thomas; Kramer-Schadt, Stephanie; Wibbelt, Gudrun

    2011-01-01

    Background Bats receive increasing attention in infectious disease studies, because of their well recognized status as reservoir species for various infectious agents. This is even more important, as bats with their capability of long distance dispersal and complex social structures are unique in the way microbes could be spread by these mammalian species. Nevertheless, infection studies in bats are predominantly limited to the identification of specific pathogens presenting a potential health threat to humans. But the impact of infectious agents on the individual host and their importance on bat mortality is largely unknown and has been neglected in most studies published to date. Methodology/Principal Findings Between 2002 and 2009, 486 deceased bats of 19 European species (family Vespertilionidae) were collected in different geographic regions in Germany. Most animals represented individual cases that have been incidentally found close to roosting sites or near human habitation in urban and urban-like environments. The bat carcasses were subjected to a post-mortem examination and investigated histo-pathologically, bacteriologically and virologically. Trauma and disease represented the most important causes of death in these bats. Comparative analysis of pathological findings and microbiological results show that microbial agents indeed have an impact on bats succumbing to infectious diseases, with fatal bacterial, viral and parasitic infections found in at least 12% of the bats investigated. Conclusions/Significance Our data demonstrate the importance of diseases and infectious agents as cause of death in European bat species. The clear seasonal and individual variations in disease prevalence and infection rates indicate that maternity colonies are more susceptible to infectious agents, underlining the possible important role of host physiology, immunity and roosting behavior as risk factors for infection of bats. PMID:22216354

  7. Characterizing Thermal features in Norris Basin, Yellowstone National Park, Using Multi- spectral Remote Sensing Data and Dynamic Calibration Procedures

    NASA Astrophysics Data System (ADS)

    Hardy, C. C.; Queen, L. P.; Heasler, H. P.; Jaworowski, C.

    2007-12-01

    A thermal infrared remote sensing project was implemented to develop methods for identifying, classifying, and mapping thermal features. This study is directed at geothermal features, with the expectation that new protocols developed here will apply to the wildland fire thermal environment. Airborne multi-spectral digital imagery were acquired over the geothermally active Norris Basin region of Yellowstone National Park, USA. Two image acquisitions were flown, with one acquisition near solar noon and the other at night. Raw data from the five sensors were uncalibrated, so a vicarious calibration procedure was developed to compute reflectance for the visible and NIR bands using an independently calibrated hyperspectral dataset. Calibration of the thermal sensor band utilized a dynamic, in-scene calibration procedure that exploited natural, pseudo-invariant thermal reference targets instrumented with in situ kinetic temperature recorders. The calibrated reflectance and radiant temperature data from each acquisition were processed and analyzed to develop a suite of thermal attributes, including radiant temperatures, a daytime-nighttime temperature difference (DeltaT), albedo, an albedo derivative (one minus albedo), and apparent thermal inertia (ATI). The albedo terms were computed using a published weighed-average albedo algorithm based on ratios of the narrowband red and near-infrared (NIR) reflectances to total solar irradiance for the respective red and NIR bandpasses. The weighing factors for each band were the proportion of total solar irradiance incident on the surface within each segment represented by a respective bandpass. In the absence of verifiable "truth," a step-wise chain of unsupervised classification and multivariate analysis exercises was performed, drawing heavily on "fuzzy truth" to assess the quality, efficiency, and efficacy of classification procedures and results. A final classification synthesizes a "geothermal phenomenology" comprised of

  8. Diallyl trisulfide inhibits angiogenic features of human umbilical vein endothelial cells by causing Akt inactivation and down-regulation of VEGF and VEGF-R2.

    PubMed

    Xiao, Dong; Li, Mengfeng; Herman-Antosiewicz, Anna; Antosiewicz, Jedrzej; Xiao, Hui; Lew, Karen L; Zeng, Yan; Marynowski, Stanley W; Singh, Shivendra V

    2006-01-01

    We have shown recently that diallyl trisulfide (DATS), a cancer-chemopreventive constituent of garlic, inactivates Akt to trigger mitochondrial translocation of proapoptotic protein BAD in human prostate cancer cells. Because Akt activation is implicated in the promotion of endothelial cell survival and angiogenesis, we hypothesized that DATS may inhibit angiogenesis. In the present study, we tested this hypothesis using human umbilical vein endothelial cells (HUVECs) as a model. Survival of HUVECs was reduced significantly in the presence of DATS in a concentration-dependent manner, with an IC50 of approximately 4 microM. The DATS-mediated suppression of HUVEC survival was associated with apoptosis induction characterized by accumulation of subdiploid cells, cytoplasmic histone-associated DNA fragmentation, and cleavage of caspase-3 and poly-(ADP-ribose)-polymerase. The DATS-induced DNA fragmentation was significantly attenuated in the presence of pan-caspase inhibitor zVAD-fmk and specific inhibitors of caspase-9 (zLEHD-fmk) and caspase-8 (zIETD-fmk). DATS treatment inhibited the formation of capillary-like tube structure and migration by HUVECs in association with suppression of vascular endothelial growth factor (VEGF) secretion and VEGF receptor-2 protein level and inactivation of Akt kinase. DATS treatment also caused activation of extracellular signal-regulated kinase 1/2 (ERK1/2) but not c-Jun NH2-terminal kinase (JNK) or p38 mitogen-activated protein kinase (p38MAPK).DATS-mediatedapoptosis induction and inhibition of HUVEC tube formation was partially but statistically significantly attenuated by pharmacologic inhibition of ERK1/2 but not JNK or p38MAPK. The present study demonstrates, for the first time, that DATS has the ability to inhibit angiogenic features of human endothelial cells. PMID:16965246

  9. [Progress on the cause and mechanism of a separation of clinical symptoms and signs and imaging features in lumbar disk herniation].

    PubMed

    Hu, Xing-xin; Liu, Li-min

    2015-10-01

    A few of patients with lumbar disk herniation having a separation of clinical symptoms and signs and imaging features, can be found in clinic, but the traditional theory of direct mechanical compression of nerve roots by herniated nucleus pulposus can't be used to explain this abnormal protrusion of lumbar intervertebral disc. The clinical symptoms and signs of the atypical lumbar disk herniation are affected by multiple factors. The indirect mechanical compression and distraction effect of spinal nerve roots may play an important role in the occurrence of the separation, and the appearance of abnormal clinical symptoms and signs is closely related to the migration of herniated nucleus pulposus tissue, transmission of injury information in the nervous system, and the complex interactions among the nucleus pulposus, dural sac and nerve roots. Moreover,the changes of microcirculation and inflammation secondary to the herniated nucleus pulposus tissue, the hyperosteogeny in the corresponding segment of the lumbar vertebrae and the posture changes all results in a diversity of symptoms and signs in patients with lumbar intervertebral disc herniation. Besides, there exist congenital variation of lumbosacral nerve roots and vertebral bodies in some patients, and the misdiagnosis or missed diagnosis of imaging finding may occur in some cases. However, the appearance of a separation of clinical symptoms and signs and imaging examination in patients may be caused by a variety of reasons in clinic. The exact mechanism involved in the interaction among nucleus pulposus tissue, dural sac and nerve root, secondary changes of pathophysiology and biomechanics around the nucleus pulposus, the determination of lesioned responsible segments, and how to overcome the limitations of imaging all need the further researches. PMID:26727796

  10. A dynamic magnetic tension force as the cause of failed solar eruptions

    NASA Astrophysics Data System (ADS)

    Myers, Clayton E.; Yamada, Masaaki; Ji, Hantao; Yoo, Jongsoo; Fox, William; Jara-Almonte, Jonathan; Savcheva, Antonia; Deluca, Edward E.

    2015-12-01

    Coronal mass ejections are solar eruptions driven by a sudden release of magnetic energy stored in the Sun’s corona. In many cases, this magnetic energy is stored in long-lived, arched structures called magnetic flux ropes. When a flux rope destabilizes, it can either erupt and produce a coronal mass ejection or fail and collapse back towards the Sun. The prevailing belief is that the outcome of a given event is determined by a magnetohydrodynamic force imbalance called the torus instability. This belief is challenged, however, by observations indicating that torus-unstable flux ropes sometimes fail to erupt. This contradiction has not yet been resolved because of a lack of coronal magnetic field measurements and the limitations of idealized numerical modelling. Here we report the results of a laboratory experiment that reveal a previously unknown eruption criterion below which torus-unstable flux ropes fail to erupt. We find that such ‘failed torus’ events occur when the guide magnetic field (that is, the ambient field that runs toroidally along the flux rope) is strong enough to prevent the flux rope from kinking. Under these conditions, the guide field interacts with electric currents in the flux rope to produce a dynamic toroidal field tension force that halts the eruption. This magnetic tension force is missing from existing eruption models, which is why such models cannot explain or predict failed torus events.

  11. Secondary sympatry caused by range expansion informs on the dynamics of microendemism in a biodiversity hotspot.

    PubMed

    Nattier, Romain; Grandcolas, Philippe; Elias, Marianne; Desutter-Grandcolas, Laure; Jourdan, Hervé; Couloux, Arnaud; Robillard, Tony

    2012-01-01

    Islands are bounded areas where high endemism is explained either by allopatric speciation through the fragmentation of the limited amount of space available, or by sympatric speciation and accumulation of daughter species. Most empirical evidence point out the dominant action of allopatric speciation. We evaluate this general view by looking at a case study where sympatric speciation is suspected. We analyse the mode, tempo and geography of speciation in Agnotecous, a cricket genus endemic to New Caledonia showing a generalized pattern of sympatry between species making sympatric speciation plausible. We obtained five mitochondrial and five nuclear markers (6.8 kb) from 37 taxa corresponding to 17 of the 21 known extant species of Agnotecous, and including several localities per species, and we conducted phylogenetic and dating analyses. Our results suggest that the diversification of Agnotecous occurred mostly through allopatric speciation in the last 10 Myr. Highly microendemic species are the most recent ones (<2 Myr) and current sympatry is due to secondary range expansion after allopatric speciation. Species distribution should then be viewed as a highly dynamic process and extreme microendemism only as a temporary situation. We discuss these results considering the influence of climatic changes combined with intricate soil diversity and mountain topography. A complex interplay between these factors could have permitted repeated speciation events and range expansion. PMID:23139758

  12. The fluid dynamics of microjet explosions caused by extremely intense X-ray pulses

    NASA Astrophysics Data System (ADS)

    Stan, Claudiu; Laksmono, Hartawan; Sierra, Raymond; Milathianaki, Despina; Koglin, Jason; Messerschmidt, Marc; Williams, Garth; Demirci, Hasan; Botha, Sabine; Nass, Karol; Stone, Howard; Schlichting, Ilme; Shoeman, Robert; Boutet, Sebastien

    2014-11-01

    Femtosecond X-ray scattering experiments at free-electron laser facilities typically requires liquid jet delivery methods to bring samples to the region of interaction with X-rays. We have imaged optically the damage process in water microjets due to intense hard X-ray pulses at the Linac Coherent Light Source (LCLS), using time-resolved imaging techniques to record movies at rates up to half a billion frames per second. For pulse energies larger than a few percent of the maximum pulse energy available at LCLS, the X-rays deposit energies much larger than the latent heat of vaporization in water, and induce a phase explosion that opens a gap in the jet. The LCLS pulses last a few tens of femtoseconds, but the full evolution of the broken jet is orders of magnitude slower - typically in the microsecond range - due to complex fluid dynamics processes triggered by the phase explosion. Although the explosion results in a complex sequence of phenomena, they lead to an approximately self-similar flow of the liquid in the jet.

  13. A dynamic magnetic tension force as the cause of failed solar eruptions

    DOE PAGESBeta

    Myers, Clayton E.; Yamada, Masaaki; Ji, Hantao; Yoo, Jongsoo; Fox, William; Jara-Almonte, Jonathan; Savcheva, Antonia; DeLuca, Edward E.

    2015-12-23

    Coronal mass ejections are solar eruptions driven by a sudden release of magnetic energy stored in the Sun's corona. In many cases, this magnetic energy is stored in long-lived, arched structures called magnetic flux ropes. When a flux rope destabilizes, it can either erupt and produce a coronal mass ejection or fail and collapse back towards the Sun. The prevailing belief is that the outcome of a given event is determined by a magnetohydrodynamic force imbalance called the torus instability. This belief is challenged, however, by observations indicating that torus-unstable flux ropes sometimes fail to erupt. This contradiction has notmore » yet been resolved because of a lack of coronal magnetic field measurements and the limitations of idealized numerical modelling. In this paper, we report the results of a laboratory experiment that reveal a previously unknown eruption criterion below which torus-unstable flux ropes fail to erupt. We find that such 'failed torus' events occur when the guide magnetic field (that is, the ambient field that runs toroidally along the flux rope) is strong enough to prevent the flux rope from kinking. Under these conditions, the guide field interacts with electric currents in the flux rope to produce a dynamic toroidal field tension force that halts the eruption. Lastly, this magnetic tension force is missing from existing eruption models, which is why such models cannot explain or predict failed torus events.« less

  14. A dynamic magnetic tension force as the cause of failed solar eruptions.

    PubMed

    Myers, Clayton E; Yamada, Masaaki; Ji, Hantao; Yoo, Jongsoo; Fox, William; Jara-Almonte, Jonathan; Savcheva, Antonia; DeLuca, Edward E

    2015-12-24

    Coronal mass ejections are solar eruptions driven by a sudden release of magnetic energy stored in the Sun's corona. In many cases, this magnetic energy is stored in long-lived, arched structures called magnetic flux ropes. When a flux rope destabilizes, it can either erupt and produce a coronal mass ejection or fail and collapse back towards the Sun. The prevailing belief is that the outcome of a given event is determined by a magnetohydrodynamic force imbalance called the torus instability. This belief is challenged, however, by observations indicating that torus-unstable flux ropes sometimes fail to erupt. This contradiction has not yet been resolved because of a lack of coronal magnetic field measurements and the limitations of idealized numerical modelling. Here we report the results of a laboratory experiment that reveal a previously unknown eruption criterion below which torus-unstable flux ropes fail to erupt. We find that such 'failed torus' events occur when the guide magnetic field (that is, the ambient field that runs toroidally along the flux rope) is strong enough to prevent the flux rope from kinking. Under these conditions, the guide field interacts with electric currents in the flux rope to produce a dynamic toroidal field tension force that halts the eruption. This magnetic tension force is missing from existing eruption models, which is why such models cannot explain or predict failed torus events. PMID:26701052

  15. A dynamic magnetic tension force as the cause of failed solar eruptions

    SciTech Connect

    Myers, Clayton E.; Yamada, Masaaki; Ji, Hantao; Yoo, Jongsoo; Fox, William; Jara-Almonte, Jonathan; Savcheva, Antonia; DeLuca, Edward E.

    2015-12-23

    Coronal mass ejections are solar eruptions driven by a sudden release of magnetic energy stored in the Sun's corona. In many cases, this magnetic energy is stored in long-lived, arched structures called magnetic flux ropes. When a flux rope destabilizes, it can either erupt and produce a coronal mass ejection or fail and collapse back towards the Sun. The prevailing belief is that the outcome of a given event is determined by a magnetohydrodynamic force imbalance called the torus instability. This belief is challenged, however, by observations indicating that torus-unstable flux ropes sometimes fail to erupt. This contradiction has not yet been resolved because of a lack of coronal magnetic field measurements and the limitations of idealized numerical modelling. In this paper, we report the results of a laboratory experiment that reveal a previously unknown eruption criterion below which torus-unstable flux ropes fail to erupt. We find that such 'failed torus' events occur when the guide magnetic field (that is, the ambient field that runs toroidally along the flux rope) is strong enough to prevent the flux rope from kinking. Under these conditions, the guide field interacts with electric currents in the flux rope to produce a dynamic toroidal field tension force that halts the eruption. Lastly, this magnetic tension force is missing from existing eruption models, which is why such models cannot explain or predict failed torus events.

  16. Seasonal Dynamics of Phlebotomine Sand Fly Species Proven Vectors of Mediterranean Leishmaniasis Caused by Leishmania infantum

    PubMed Central

    Alten, Bulent; Maia, Carla; Afonso, Maria Odete; Campino, Lenea; Jiménez, Maribel; González, Estela; Molina, Ricardo; Bañuls, Anne Laure; Prudhomme, Jorian; Vergnes, Baptiste; Toty, Celine; Cassan, Cécile; Rahola, Nil; Thierry, Magali; Sereno, Denis; Bongiorno, Gioia; Bianchi, Riccardo; Khoury, Cristina; Tsirigotakis, Nikolaos; Dokianakis, Emmanouil; Antoniou, Maria; Christodoulou, Vasiliki; Mazeris, Apostolos; Karakus, Mehmet; Ozbel, Yusuf; Arserim, Suha K.; Erisoz Kasap, Ozge; Gunay, Filiz; Oguz, Gizem; Kaynas, Sinan; Tsertsvadze, Nikoloz; Tskhvaradze, Lamzira; Gramiccia, Marina; Volf, Petr; Gradoni, Luigi

    2016-01-01

    Background The recent geographical expansion of phlebotomine vectors of Leishmania infantum in the Mediterranean subregion has been attributed to ongoing climate changes. At these latitudes, the activity of sand flies is typically seasonal; because seasonal phenomena are also sensitive to general variations in climate, current phenological data sets can provide a baseline for continuing investigations on sand fly population dynamics that may impact on future scenarios of leishmaniasis transmission. With this aim, in 2011–2013 a consortium of partners from eight Mediterranean countries carried out entomological investigations in sites where L. infantum transmission was recently reported. Methods/Principal Findings A common protocol for sand fly collection included monthly captures by CDC light traps, complemented by sticky traps in most of the sites. Collections were replicated for more than one season in order to reduce the effects of local weather events. In each site, the trapping effort was left unchanged throughout the survey to legitimate inter-seasonal comparisons. Data from 99,000 collected specimens were analyzed, resulting in the description of seasonal dynamics of 56,000 sand flies belonging to L. infantum vector species throughout a wide geographical area, namely P. perniciosus (Portugal, Spain and Italy), P. ariasi (France), P. neglectus (Greece), P. tobbi (Cyprus and Turkey), P. balcanicus and P. kandelakii (Georgia). Time of sand fly appearance/disappearance in collections differed between sites, and seasonal densities showed variations in each site. Significant correlations were found between latitude/mean annual temperature of sites and i) the first month of sand fly appearance, that ranged from early April to the first half of June; ii) the type of density trend, varying from a single peak in July/August to multiple peaks increasing in magnitude from May through September. A 3-modal trend, recorded for P. tobbi in Cyprus, represents a novel

  17. Differentiating causes for erosion at the catchment scale: do soil conservation measures mitigate weather dynamics?

    NASA Astrophysics Data System (ADS)

    Barneveld, Robert; Greipsland, Inga

    2016-04-01

    The efficacy of most measures to control soil loss is well established at the field or plot scale. Less well documented are the changes in hydrological behaviour and sediment production at the scale of the (small) catchment. In Norway, incentives to reduce tillage have been in place for over decades. However, even long time (20 years) discharge monitoring of a series of small catchments does not show a clear effect of the application of conservation measures. This research hypothesizes that the effect of weather conditions for a 4.2 km2 catchment in southeastern Norway outweighs the effect of conservation measures in the time series on runoff and sediment load. To test this, it was assumed that trends and changes in soil loss E over time are the product of an agromic index C, precipitation P and rainfall erosivity R. The values of C were calculated based on extensive farm records, covering every tillage operation for every field in the catchment for the period of investigation. Runoff and sediment load records were used to parameterise and test different correlative models. In order to quantify the effect of topography on the degree to which conservations measures reduce soil loss at catchment level, a spatially distributed connectivity index was calculated and multiplied with C. Calculations were carried out for a 10 year period, in monthly time steps. The following statistical models proved the most promising to correlate sediment load to precipitation and agronomic practice. Et=a \\cdot Ptb \\cdot Pt-1c \\cdot Ctd Et=a \\cdot Rtb \\cdot Pt-1c \\cdot Ctd where Pt-1c, the precipition in the prior month, is a proxy indicator for antecedent moisture conditions. The results show that precipitation dynamics outweigh the effect of soil conservation measures for this typical agricultural catchment. It also shows that the inclusion of a hydrological connectivity index improves the quantification of the effect of soil conservation measures on the catchment scale.

  18. Dynamic causes of the relation between area and age of the ocean floor

    NASA Astrophysics Data System (ADS)

    Coltice, N.; Rolf, T.; Tackley, P. J.; Labrosse, S.

    2012-04-01

    The distribution of seafloor ages determines fundamental characteristics of our planet: sea-level , ocean chemistry, tectonic forces and heat loss. The present-day distribution suggests that subduction affects lithosphere of all ages with the same probability (B. Parsons, J. Geaophys. Res 87, 289-302, 1982). This is at odds with the theory of thermal convection which predicts that subduction should happen once a critical age has been reached. So far, the area-age distribution remains a primary constraint, which convection models have failed to satisfy (S. Labrosse and C. Jaupart, Earth Planet. Sci. Lett. 260, 465-481, 2007). We will show that combined action of plate-like behavior and continents causes the seafloor area-age distribution in spherical models of mantle convection to be Earth-like. Our simulations suggest that the seafloor age distribution on Earth has evolved in the past 500~Myrs, along with peaks of production rate of new ocean floor that could have reached twice the present-day value.

  19. A Molecular Rotor that Measures Dynamic Changes of Lipid Bilayer Viscosity Caused by Oxidative Stress.

    PubMed

    Vyšniauskas, Aurimas; Qurashi, Maryam; Kuimova, Marina K

    2016-09-01

    Oxidation of cellular structures is typically an undesirable process that can be a hallmark of certain diseases. On the other hand, photooxidation is a necessary step of photodynamic therapy (PDT), a cancer treatment causing cell death upon light irradiation. Here, the effect of photooxidation on the microscopic viscosity of model lipid bilayers constructed of 1,2-dioleoyl-sn-glycero-3-phosphocholine has been studied. A molecular rotor has been employed that displays a viscosity-dependent fluorescence lifetime as a quantitative probe of the bilayer's viscosity. Thus, spatially-resolved viscosity maps of lipid photooxidation in giant unilamellar vesicles (GUVs) were obtained, testing the effect of the positioning of the oxidant relative to the rotor in the bilayer. It was found that PDT has a strong impact on viscoelastic properties of lipid bilayers, which 'travels' through the bilayer to areas that have not been irradiated directly. A dramatic difference in viscoelastic properties of oxidized GUVs by Type I (electron transfer) and Type II (singlet oxygen-based) photosensitisers was also detected. PMID:27487026

  20. Do Woody Plants Operate Near the Point of Catastrophic Xylem Dysfunction Caused by Dynamic Water Stress? 1

    PubMed Central

    Tyree, Melvin T.; Sperry, John S.

    1988-01-01

    We discuss the relationship between the dynamically changing tension gradients required to move water rapidly through the xylem conduits of plants and the proportion of conduits lost through embolism as a result of water tension. We consider the implications of this relationship to the water relations of trees. We have compiled quantitative data on the water relations, hydraulic architecture and vulnerability of embolism of four widely different species: Rhizophora mangle, Cassipourea elliptica, Acer saccharum, and Thuja occidentalis. Using these data, we modeled the dynamics of water flow and xylem blockage for these species. The model is specifically focused on the conditions required to generate `runaway embolism,' whereby the blockage of xylem conduits through embolism leads to reduced hydraulic conductance causing increased tension in the remaining vessels and generating more tension in a vicious circle. The model predicted that all species operate near the point of catastrophic xylem failure due to dynamic water stress. The model supports Zimmermann's plant segmentation hypothesis. Zimmermann suggested that plants are designed hydraulically to sacrifice highly vulnerable minor branches and thus improve the water balance of remaining parts. The model results are discussed in terms of the morphology, hydraulic architecture, eco-physiology, and evolution of woody plants. PMID:16666351

  1. Evaluation of bridge instability caused by dynamic scour based on fractal theory

    NASA Astrophysics Data System (ADS)

    Lin, Tzu-Kang; Wu, Rih-Teng; Chang, Kuo-Chun; Shian Chang, Yu

    2013-07-01

    Given their special structural characteristics, bridges are prone to suffer from the effects of many hazards, such as earthquakes, wind, or floods. As most of the recent unexpected damage and destruction of bridges has been caused by hydraulic issues, monitoring the scour depth of bridges has become an important topic. Currently, approaches to scour monitoring mainly focus on either installing sensors on the substructure of a bridge or identifying the physical parameters of a bridge, which commonly face problems of system survival or reliability. To solve those bottlenecks, a novel structural health monitoring (SHM) concept was proposed by utilizing the two dominant parameters of fractal theory, including the fractal dimension and the topothesy, to evaluate the instability condition of a bridge structure rapidly. To demonstrate the performance of this method, a series of experiments has been carried out. The function of the two parameters was first determined using data collected from a single bridge column scour test. As the fractal dimension gradually decreased, following the trend of the scour depth, it was treated as an alternative to the fundamental frequency of a bridge structure in the existing methods. Meanwhile, the potential of a positive correlation between the topothesy and the amplitude of vibration data was also investigated. The excellent sensitivity of the fractal parameters related to the scour depth was then demonstrated in a full-bridge experiment. Moreover, with the combination of these two parameters, a safety index to detect the critical scour condition was proposed. The experimental results have demonstrated that the critical scour condition can be predicted by the proposed safety index. The monitoring system developed greatly advances the field of bridge scour health monitoring and offers an alternative choice to traditional scour monitoring technology.

  2. Water-level oscillations caused by volumetric and deviatoric dynamic strains

    NASA Astrophysics Data System (ADS)

    Shalev, Eyal; Kurzon, Ittai; Doan, Mai-Linh; Lyakhovsky, Vladimir

    2016-02-01

    Travelling seismic waves and Earth tides are known to cause oscillations in well water levels due to the volumetric strain characteristics of the ground motion. Although the response of well water levels to S and Love waves has been reported, it has not yet been quantified. In this paper we describe and explain the behaviour of a closed artesian water well (Gomè 1) in response to teleseismic earthquakes. This well is located within a major fault zone and screened at a highly damaged (cracked) sandstone layer. We adopt the original Skempton approach where both volumetric and deviatoric stresses (and strains) affect pore pressure. Skempton's coefficients < tex - mathid = "IM0001" > B and < tex - mathid = "IM0002" > A couple the volumetric and deviatoric stresses respectively with pore pressure and < tex - mathid = "IM0003" > BKu and < tex - mathid = "IM0004" > N are the equivalent coupling terms to volumetric and deviatoric strains. The water level in this well responds dramatically to volumetric strain (P and Rayleigh waves) as well as to deviatoric strain (S and Love waves). This response is explained by the nonlinear elastic behaviour of the highly damaged rocks. The water level response to deviatoric strain depends on the damage in the rock; deviatoric strain loading on damaged rock results in high water level amplitudes, and no response in undamaged rock. We find high values of < tex - mathid = "IM0005" > N= 8.5 GPa that corresponds to -0.5 < A < -0.25 expected at highly damaged rocks. We propose that the Gomè 1 well is located within fractured rocks, and therefore, dilatency is high, and the response of water pressure to deviatoric deformation is high. This analysis is supported by the agreement between the estimated compressibility of the aquifer, independently calculated from Earth tides, seismic response of the water pressure and other published data.

  3. Statistical Investigations on Solar Wind Dynamic Pressure Pulses:Basic features and Their Impacts on Geosynchronous Magnetic Fields

    NASA Astrophysics Data System (ADS)

    Zuo, Pingbing; Feng, Xueshang

    2016-07-01

    Solar wind dynamic pressure pulse (DPP) structures, across which the dynamic pressure abruptly changes over timescales from a few seconds to several minutes, are often observed in the near-Earth space environment. Recently we have developed a novel procedure that is able to rapidly identify the DPPs from the plasma data stream, and simultaneously define the transition region and smartly select the upstream and downstream region for analysis. The plasma data with high time-resolution from 3DP instrument on board the WIND spacecraft are inspected with this automatic DPP-searching code, and a complete list of solar wind DPPs of historic WIND observations are built up. We perform a statistical survey on the properties of DPPs near 1 AU based on this event list. It is found that overwhelming majority of DPPs are associated with the solar wind disturbances including the CME-related flows, the corotating interaction regions, as well as the complex ejecta. The annual variations of the averaged occurrence rate of DPPs are roughly in phase with the solar activities. Although the variabilities of geosynchronous magnetic fields (GMFs) due to the impact of positive DPPs have been well established, there appears no systematic investigations on the response of GMFs to negative DPPs. Here we also study the decompression/compression effects of very strong negative/positive DPPs on GMFs under northward IMFs. In response to the decompression of strong negative DPPs, GMFs on dayside, near the dawn and dusk on nightside are generally depressed. But near the midnight region, the responses of GMF are very diverse, being either positive or negative. For part of events when GOES is located at the midnight sector, GMF is found to abnormally increase as the result of magnetospheric decompression caused by negative DPPs. It is known that on certain conditions magnetic depression of nightside GMFs can be caused by the impact of positive DPPs. Statistically, both the decompression effect of

  4. Study of solar features causing GMSs with 250c'gamma' 'smaller than' H 'smaller than' 400'gamma' during the period 1999-2010

    NASA Astrophysics Data System (ADS)

    Kumar, Rajiv

    2016-07-01

    The effect of solar features on geospheric conditions leading to geomagnetic storms (GMSs) with planetary index,A P ≥ 20 and the range of horizontal component of the Earth's magnetic field H such that 250γ causing GMSs at the Earth. Keywords Geomagnetic storm solar flares active

  5. Time-varying imagery of ice features dynamic scattering in presence climate change: polytypical lakes Ladoga and Peipus as example

    NASA Astrophysics Data System (ADS)

    Melentyev, V.; Melentyev, K.; Pettersson, L.; Mushkudiany, M.

    2009-04-01

    The Problem of dynamical instability of ice conditions and modification of ice regime of polytypical lakes owing to global warming was investigated using time-varying satellite imagery. Deep-water Lake Ladoga and shallow-water Lake Peipus both situated at the north-western part of Russian Federation in moderate climatic zone but possessed different heat capacity were used for comparative studies. The comprehensive analysis of ERS/RADARSAT/Envisat SAR images was provided using the results of long-term studies of thermal structures of these inland water bodies and peculiarities of their variability during open water season as well calculations of heat supply in different weather conditions. 1993-2008 NERSC/NIERSC SAR archive as well materials sub-satellite experiments on board research vessel and research aircraft since 1960-s is used. Shipborne observations were used for validation satellite information. Thematic interpretation of satellite data shows that SAR signature of ice could be applied as tracer of various natural processes and phenomena, including climatically and ecologically important ones. As result dependence of hydrological features and the time of freeze-up and ice destruction in both selected lakes in consequence of climate change and softening of winter severity in nowadays was assessed. Wind regime patterns (speed and direction) were analyzed using algorithm CMOD 4 and in the upshot the increase of seasonal and regional variability of windy weather in studied regions was fixed. In frame of these studies wind cadastre appurtenant to the NW part of RF was composed on the basis of satellite SAR survey. In particular the modification of "wind climate" was disclosed. And what is more: it was revealed that intensification of windy weather resulted in intensification of dynamic range of water and ice exchange between the central part of both studied polytypical lakes and their gulfs. These natural processes took place due to widening duration of the open

  6. Time-varying imagery of ice features dynamic scattering in presence climate change: polytypical lakes Ladoga and Peipus as example

    NASA Astrophysics Data System (ADS)

    Melentyev, V. V.; Melentyev, K. V.; Pettersson, L. H.; Mushkudany, M. I.

    2009-04-01

    Problem of dynamical instability of ice conditions and modification of ice regime of polytypical lakes owing to global warming were investigated using time-varying satellite imagery. Deep-water Lake Ladoga and shallow-water Lake Peipus both situated at the north-western part of Russian Federation in moderate climatic zone but possessed different heat capacity were used for comparative studies. The comprehensive analysis of ERS/RADARSAT/Envisat SAR images was provided using the results of long-term studies of thermal structures of these inland waterbodies and peculiarities of their variability during open water season as well calculations of heat supply in different weather conditions. 1993-2008 NERSC/NIERSC SAR archive as well materials sub-satellite experiments onboard research vessel and research aircraft since 1960-s is used. Shipborne observations were used for validation satellite information. Thematic interpretation of satellite data shows that SAR signature of ice could be applied as tracer of various natural processes and phenomena, including climatically and ecologically important ones. As result dependence of hydrological features and the time of freeze-up and ice destruction in both selected lakes in consequence of climate change and softening of winter severity in nowadays was assessed. Wind regime patterns (speed and direction) were analyzed using algorithm CMOD 4 and in the upshot the increase of seasonal and regional variability of windy weather in studied regions was fixed. In frame of these studies wind cadastre appurtenant to the NW part of RF was composed on the basis of satellite SAR survey. In particular the modification of "wind climate" was disclosed. And what is more: it was revealed that intensification of windy weather resulted in intensification of dynamic range of water and ice exchange between the central part of both studied polytypical lakes and their gulfs. These natural processes took place due to widening duration of the open water

  7. Salient Features of the 2015 Gorkha, Nepal Earthquake in Relation to Earthquake Cycle and Dynamic Rupture Models

    NASA Astrophysics Data System (ADS)

    Ampuero, J. P.; Meng, L.; Hough, S. E.; Martin, S. S.; Asimaki, D.

    2015-12-01

    Two salient features of the 2015 Gorkha, Nepal, earthquake provide new opportunities to evaluate models of earthquake cycle and dynamic rupture. The Gorkha earthquake broke only partially across the seismogenic depth of the Main Himalayan Thrust: its slip was confined in a narrow depth range near the bottom of the locked zone. As indicated by the belt of background seismicity and decades of geodetic monitoring, this is an area of stress concentration induced by deep fault creep. Previous conceptual models attribute such intermediate-size events to rheological segmentation along-dip, including a fault segment with intermediate rheology in between the stable and unstable slip segments. We will present results from earthquake cycle models that, in contrast, highlight the role of stress loading concentration, rather than frictional segmentation. These models produce "super-cycles" comprising recurrent characteristic events interspersed by deep, smaller non-characteristic events of overall increasing magnitude. Because the non-characteristic events are an intrinsic component of the earthquake super-cycle, the notion of Coulomb triggering or time-advance of the "big one" is ill-defined. The high-frequency (HF) ground motions produced in Kathmandu by the Gorkha earthquake were weaker than expected for such a magnitude and such close distance to the rupture, as attested by strong motion recordings and by macroseismic data. Static slip reached close to Kathmandu but had a long rise time, consistent with control by the along-dip extent of the rupture. Moreover, the HF (1 Hz) radiation sources, imaged by teleseismic back-projection of multiple dense arrays calibrated by aftershock data, was deep and far from Kathmandu. We argue that HF rupture imaging provided a better predictor of shaking intensity than finite source inversion. The deep location of HF radiation can be attributed to rupture over heterogeneous initial stresses left by the background seismic activity

  8. Biphasic toxicodynamic features of some antimicrobial agents on microbial growth: a dynamic mathematical model and its implications on hormesis

    PubMed Central

    2010-01-01

    Background In the present work, we describe a group of anomalous dose-response (DR) profiles and develop a dynamic model that is able to explain them. Responses were obtained from conventional assays of three antimicrobial agents (nisin, pediocin and phenol) against two microorganisms (Carnobacterium piscicola and Leuconostoc mesenteroides). Results Some of these anomalous profiles show biphasic trends which are usually attributed to hormetic responses. But they can also be explained as the result of the time-course of the response from a microbial population with a bimodal distribution of sensitivity to an effector, and there is evidence suggesting this last origin. In light of interest in the hormetic phenomenology and the possibility of confusing it with other phenomena, especially in the bioassay of complex materials we try to define some criteria which allow us to distinguish between sensu stricto hormesis and biphasic responses due to other causes. Finally, we discuss some problems concerning the metric of the dose in connection with the exposure time, and we make a cautionary suggestion about the use of bacteriocins as antimicrobial agents. Conclusions The mathematical model proposed, which combines the basis of DR theory with microbial growth kinetics, can generate and explain all types of anomalous experimental profiles. These profiles could also be described in a simpler way by means of bisigmoidal equations. Such equations could be successfully used in a microbiology and toxicology context to discriminate between hormesis and other biphasic phenomena. PMID:20723220

  9. O the Foundations of the Dynamical Theory of Fractured Porous Media and the Gravity Variations Caused by Dilatancies.

    NASA Astrophysics Data System (ADS)

    Sun, Yue-Feng

    This thesis investigates the dynamical theory of multiphase fractured porous media, by which the shear wave velocities can now be obtained that are in agreement with experiments, which were against the prediction of the Biot theory. The anisotropy, P and S wave velocities, and also waveforms can now be explicitly expressed as functions of structural, physical, and reservoir parameters such as porosity and pore fluid content, which are the key for the enhancement of seismic resolution and the determination of detailed subsurface structures and in-situ physical properties of subsurface materials, and so are essential for reservoir characterization and reservoir modeling. In addition, there generally exist 2 times A kinds of waves in an A-phase fractured porous medium, i.e., A kinds of P (compressional) waves and A kinds of S (shear) waves. The theory includes the Biot theory and the squirt mechanisms as special cases. The theory is developed using topological spaces and the principle of covariance. The basic theory of 3A -dimensional Riemannian manifold of an A-phase fractured porous medium is given. The equations governing the structural evolution and the interactions between physical properties and structural changes in space and time are also derived, which are needed to understand many new phenomena associated with structural aggregated systems in many fields such as the studies of multiphase structural media, non-Newtonian fluids, and condensed-matter physics. The thermo-dynamics of structural media is also discussed. The deformation, fracturing, and stress relaxation with or without fluid invasion cause dilatations of the fractured porous medium under a tectonic stress. The gravity change caused by these dilatancies has been formulated using the variational principle. The concept of mepicentroid is developed, which, differing from the concept of epicenter, is an essential concept for understanding the association of gravity variation in space and time with the

  10. Molecular Features Contributing to Virus-Independent Intracellular Localization and Dynamic Behavior of the Herpesvirus Transport Protein US9

    PubMed Central

    Pedrazzi, Manuela; Nash, Bradley; Meucci, Olimpia; Brandimarti, Renato

    2014-01-01

    Reaching the right destination is of vital importance for molecules, proteins, organelles, and cargoes. Thus, intracellular traffic is continuously controlled and regulated by several proteins taking part in the process. Viruses exploit this machinery, and viral proteins regulating intracellular transport have been identified as they represent valuable tools to understand and possibly direct molecules targeting and delivery. Deciphering the molecular features of viral proteins contributing to (or determining) this dynamic phenotype can eventually lead to a virus-independent approach to control cellular transport and delivery. From this virus-independent perspective we looked at US9, a virion component of Herpes Simplex Virus involved in anterograde transport of the virus inside neurons of the infected host. As the natural cargo of US9-related vesicles is the virus (or its parts), defining its autonomous, virus-independent role in vesicles transport represents a prerequisite to make US9 a valuable molecular tool to study and possibly direct cellular transport. To assess the extent of this autonomous role in vesicles transport, we analyzed US9 behavior in the absence of viral infection. Based on our studies, Us9 behavior appears similar in different cell types; however, as expected, the data we obtained in neurons best represent the virus-independent properties of US9. In these primary cells, transfected US9 mostly recapitulates the behavior of US9 expressed from the viral genome. Additionally, ablation of two major phosphorylation sites (i.e. Y32Y33 and S34ES36) have no effect on protein incorporation on vesicles and on its localization on both proximal and distal regions of the cells. These results support the idea that, while US9 post-translational modification may be important to regulate cargo loading and, consequently, virion export and delivery, no additional viral functions are required for US9 role in intracellular transport. PMID:25133647

  11. Is the 21-micron Feature Observed in Some Post-AGB Stars Caused by the Interaction Between Ti Atoms and Fullerenes?

    NASA Technical Reports Server (NTRS)

    Kimura, Yuki; Nuth, Joseph A. III; Ferguson, Frank T.

    2005-01-01

    Recent measurements of fullerenes and Ti atoms recorded in our laboratory have demonstrated the presence of an infrared feature near 21 pm. The feature observed has nearly the same shape and position as is observed for one of the most enigmatic features in post-asymptotic giant blanch (AGB) stars. In our experimental system large cage carbon particles, such as large fullerenes, were produced from CO gas by the Boudouard reaction. Large-cage carbon particles intermixed with Ti atoms were produced by the evaporation of a Ti metal wrapped carbon electrode in CO gas. The infrared spectra of large fullerenes interacting with Ti atoms show a characteristic feature at 20.3 micron that closely corresponds to the 20.1 micron feature observed in post-AGB stars. Both the lab- oratory and stellar spectra also show a small but significant peak at 19.0 micron, which is attributed to fullerenes. Here, we propose that the interaction between fullerenes and Ti atoms may be a plausible explanation for the 21-micron feature seen in some post-AGB stars.

  12. Recent calving dynamics of Glaciar Jorge Montt (Southern Patagonia Icefield) based on feature tracking techniques and oceanographic surveys

    NASA Astrophysics Data System (ADS)

    Bown, F.; Moffat, C. F.; Rivera, A.; Cisternas, S.; Kohoutek, T.

    2013-12-01

    Glaciers in the Southern Patagonia Icefield (SPI) have been retreating, thinning and accelerating in recent decades. Most of the SPI is comprised of temperate ice, therefore melting is the dominant wasting factor, however, calving is also playing a very important role, especially because calving is enhancing ice dynamic responses, mainly when glaciers calve into deep waters. Some of the most exacerbated responses are connected to the well documented and long-term tidewater calving cycle (TCC) overlapped by recent climate-related glacier responses. Glaciar Jorge Montt (48S/73W), is a tidewater glacier (~500 km2) which has experienced the maximum frontal retreat of the whole SPI (near 20 km in 112 years) while retreating up to 400 m water depth. Dead trees found in areas recently open by the glacier's retreat prove a date for the previous advancing cycle which took place during the Little Ice Age (250-400 years BP). This result indicates that the glacier is experiencing the retreating phase of the TCC in centennial time-scales. However, very little is known if this phase will stop or will continue, or how do climate change dynamcis will affect it. In order to understand the present behaviour of the glacier, several surveys have recently been conducted in the area, including airborne lidar and radar surveys, water depth measurements and ice dynamic studies. In order to survey the ice dynamic of the glacier front in connection with tides at the inner fjord, a camera pointing to the glacier terminus and collecting up to 8 photographs per day was installed in April 2012. The camera was continuously working for 60 days, allowing to study in detail the ice velocities, calving fluxes and tides near the ice. Thanks to the geo-location of the oblique photographs, feature tracking techniques were applied to the series in order to determine ice velocities and frontal retreat during the operational period. The resulting average velocities are lower than 10 m d-1, which are

  13. High-frequency vibration energy harvesting from impulsive excitation utilizing intentional dynamic instability caused by strong nonlinearity

    NASA Astrophysics Data System (ADS)

    Remick, Kevin; Dane Quinn, D.; Michael McFarland, D.; Bergman, Lawrence; Vakakis, Alexander

    2016-05-01

    The authors investigate a vibration-based energy harvesting system utilizing essential (nonlinearizable) nonlinearities and electromagnetic coupling elements. The system consists of a grounded, weakly damped linear oscillator (primary system) subjected to a single impulsive load. This primary system is coupled to a lightweight, damped oscillating attachment (denoted as nonlinear energy sink, NES) via a neodymium magnet and an inductance coil, and a piano wire, which generates an essential geometric cubic stiffness nonlinearity. Under impulsive input, the transient damped dynamics of this system exhibit transient resonance captures (TRCs) causing intentional large-amplitude and high-frequency instabilities in the response of the NES. These TRCs result in strong energy transfer from the directly excited primary system to the light-weight attachment. The energy is harvested by the electromagnetic elements in the coupling and, in the present case, dissipated in a resistive element in the electrical circuit. The primary goal of this work is to numerically, analytically, and experimentally demonstrate the efficacy of employing this type of intentional high-frequency dynamic instability to achieve enhanced vibration energy harvesting under impulsive excitation.

  14. 18F-FDG PET imaging for identifying the dynamics of intestinal disease caused by SFTSV infection in a mouse model

    PubMed Central

    Hayasaka, Daisuke; Nishi, Kodai; Fuchigami, Takeshi; Shiogama, Kazuya; Onouchi, Takanori; Shimada, Satoshi; Tsutsumi, Yutaka; Morita, Kouichi

    2016-01-01

    Severe fever with thrombocytopenia syndrome (SFTS) is an emerging disease that causes fever, enteritis, thrombocytopenia, and leucopenia and can be fatal in up to 30% of cases. However, the mechanism of severe disease is not fully understood. Molecular imaging approaches, such as positron-emission tomography (PET), are functional in vivo imaging techniques that provide real-time dynamics of disease progression, assessments of pharmacokinetics, and diagnoses for disease progression. Molecular imaging also potentially provides useful approaches to explore the pathogenesis of viral infections. Thus, the purpose of this study was to image the pathological features of SFTSV infection in vivo by PET imaging. In a mouse model, we showed that 18F-FDG accumulations clearly identified the intestinal tract site as a pathological site. We also demonstrated that 18F-FDG PET imaging can assess disease progression and response to antiserum therapy within the same individual. This is the first report demonstrating a molecular imaging strategy for SFTSV infection. Our results provide potentially useful information for preclinical studies such as the elucidation of the mechanism of SFTSV infection in vivo and the assessment of drugs for SFTS treatment. PMID:26700962

  15. 18F-FDG PET imaging for identifying the dynamics of intestinal disease caused by SFTSV infection in a mouse model.

    PubMed

    Hayasaka, Daisuke; Nishi, Kodai; Fuchigami, Takeshi; Shiogama, Kazuya; Onouchi, Takanori; Shimada, Satoshi; Tsutsumi, Yutaka; Morita, Kouichi

    2016-01-01

    Severe fever with thrombocytopenia syndrome (SFTS) is an emerging disease that causes fever, enteritis, thrombocytopenia, and leucopenia and can be fatal in up to 30% of cases. However, the mechanism of severe disease is not fully understood. Molecular imaging approaches, such as positron-emission tomography (PET), are functional in vivo imaging techniques that provide real-time dynamics of disease progression, assessments of pharmacokinetics, and diagnoses for disease progression. Molecular imaging also potentially provides useful approaches to explore the pathogenesis of viral infections. Thus, the purpose of this study was to image the pathological features of SFTSV infection in vivo by PET imaging. In a mouse model, we showed that 18F-FDG accumulations clearly identified the intestinal tract site as a pathological site. We also demonstrated that 18F-FDG PET imaging can assess disease progression and response to antiserum therapy within the same individual. This is the first report demonstrating a molecular imaging strategy for SFTSV infection. Our results provide potentially useful information for preclinical studies such as the elucidation of the mechanism of SFTSV infection in vivo and the assessment of drugs for SFTS treatment. PMID:26700962

  16. Molecular dynamics simulation for the cluster formation process of Lennard-Jones particles: Magic numbers and characteristic features

    NASA Astrophysics Data System (ADS)

    Ikeshoji, Tamio; Hafskjold, Bjørn; Hashi, Yuichi; Kawazoe, Yoshiyuki

    1996-09-01

    Cluster formation of Lennard-Jones particles (65 536 atoms in a unit cell with an overall number density equal to 0.0149) was simulated by molecular dynamics. The temperature was set to decrease linearly with time by various thermostats, starting from a gas state temperature and ending at zero temperature. With the Nosé-Hoover thermostat, it was found that the translational temperature of the clusters suddenly decreased almost to zero when the cluster formation drastically increased around a reduced temperature (T*) of 0.5, while the internal temperature decreased linearly. Using the Andersen thermostat, which could simulate the aggregation of particles in an inert gas, both the internal and translational temperatures decreased almost linearly with time. When these thermostats were used, cluster-cluster and cluster-atom collisions did not give any magic number peaks in the size distribution up to 250 atoms/cluster at any temperature. Careful tracing of the cluster growth of 13-atom clusters showed no difference in reactivity between icosahedral and nonicosahedral clusters. To simulate cooling in a supersonic jet, a thermostat which controlled only the translational temperature was introduced. After the clusters were formed by cooling the system with this thermostat, their internal temperature stayed at T*≊0.5, while the translational temperature decreased linearly to zero with time as it was controlled. A long-time evaporation from these high-temperature clusters gave peaks at 13 and 19 (and less significantly at 23 and 26) which are magic number sizes corresponding to single, double, triple, and quadruple icosahedra, respectively. The internal temperatures of 13- and 19-atom clusters were higher than those of other size clusters. Higher evaporation energy was observed for the clusters of 13, 19, 23, and 26 atoms than for other size clusters after the long-time evaporation, but only the 13-atom clusters had the higher evaporation energy after cooling by the

  17. T-RECS: STABLE SELECTION OF DYNAMICALLY FORMED GROUPS OF FEATURES WITH APPLICATION TO PREDICTION OF CLINICAL OUTCOMES

    PubMed Central

    Huang, Grace T.; Tsamardinos, Ioannis; Raghu, Vineet; Kaminski, Naftali; Benos, Panayiotis V.

    2014-01-01

    Feature selection is used extensively in biomedical research for biomarker identification and patient classification, both of which are essential steps in developing personalized medicine strategies. However, the structured nature of the biological datasets and high correlation of variables frequently yield multiple equally optimal signatures, thus making traditional feature selection methods unstable. Features selected based on one cohort of patients, may not work as well in another cohort. In addition, biologically important features may be missed due to selection of other co-clustered features We propose a new method, Tree-guided Recursive Cluster Selection (T-ReCS), for efficient selection of grouped features. T-ReCS significantly improves predictive stability while maintains the same level of accuracy. T-ReCS does not require an a priori knowledge of the clusters like group-lasso and also can handle “orphan” features (not belonging to a cluster). T-ReCS can be used with categorical or survival target variables. Tested on simulated and real expression data from breast cancer and lung diseases and survival data, T-ReCS selected stable cluster features without significant loss in classification accuracy. PMID:25592602

  18. Ocean dynamic processes causing spatially heterogeneous distribution of sedimentary caesium-137 massively released from the Fukushima Daiichi Nuclear Power Plant

    NASA Astrophysics Data System (ADS)

    Higashi, H.; Morino, Y.; Furuichi, N.; Ohara, T.

    2015-12-01

    Massive amounts of anthropogenic radiocaesium 137Cs that were released into the environment by the Fukushima Daiichi Nuclear Power Plant accident in March 2011 are widely known to have extensively migrated to Pacific Ocean sediment off of eastern Japan. Several recent reports have stated that the sedimentary 137Cs is now stable with a remarkably heterogeneous distribution. The present study elucidates ocean dynamic processes causing this heterogeneous sedimentary 137Cs distribution in and around the shelf off Fukushima and adjacent prefectures. We performed a numerical simulation of oceanic 137Cs behaviour for about 10 months after the accident, using a comprehensive dynamic model involving advection-diffusion transport in seawater, adsorption and desorption to and from particulate matter, sedimentation and suspension on and from the bottom, and vertical diffusion transport in the sediment. A notable simulated result was that the sedimentary 137Cs significantly accumulated in a swath just offshore of the shelf break (along the 50-100 m isobath) as in recent observations, although the seabed in the entire simulation domain was assumed to have ideal properties such as identical bulk density, uniform porosity, and aggregation of particles with a single grain diameter. This result indicated that the heterogeneous sedimentary 137Cs distribution was not necessarily a result of the spatial distribution of 137Cs sediment adsorptivity. The present simulation suggests that the shape of the swath is mainly associated with spatiotemporal variation between bottom shear stress in the shallow shelf (< 50 m depths) and that offshore of the shelf break. In a large part of the shallow shelf, the simulation indicated that strong bottom friction suspending particulate matter from the seabed frequently occurred via a periodic spring tide about every 2 weeks and via occasional strong wind. The sedimentary 137Cs thereby could hardly stay on the surface of the seabed with the result that

  19. The MECP2 variant c.925C>T (p.Arg309Trp) causes intellectual disability in both males and females without classic features of Rett syndrome.

    PubMed

    Schönewolf-Greulich, B; Tejada, M-I; Stephens, K; Hadzsiev, K; Gauthier, J; Brøndum-Nielsen, K; Pfundt, R; Ravn, K; Maortua, H; Gener, B; Martínez-Bouzas, C; Piton, A; Rouleau, G; Clayton-Smith, J; Kleefstra, T; Bisgaard, A-M; Tümer, Z

    2016-06-01

    Missense MECP2 variants can have various phenotypic effects ranging from a normal phenotype to typical Rett syndrome (RTT). In females, the phenotype can also be influenced by the X-inactivation pattern. In this study, we present detailed clinical descriptions of six patients with a rare base-pair substitution affecting Arg309 at the C-terminal end of the transcriptional repression domain (TRD). All patients have intellectual disability and present with some RTT features, but they do not fulfill the clinical criteria for typical or atypical RTT. Most of the patients also have mild facial dysmorphism. Intriguingly, the mother of an affected male patient is an asymptomatic carrier of this variant. It is therefore likely that the p.(Arg309Trp) variation does not necessarily lead to male lethality, and it results in a wide range of clinical features in females, probably influenced by different X-inactivation patterns in target tissues. PMID:26936630

  20. Dynamic GLUT4 sorting through a syntaxin-6 compartment in muscle cells is derailed by insulin resistance-causing ceramide

    PubMed Central

    Foley, Kevin P.; Klip, Amira

    2014-01-01

    ABSTRACT GLUT4 constitutively recycles between the plasma membrane and intracellular depots. Insulin shifts this dynamic equilibrium towards the plasma membrane by recruiting GLUT4 to the plasma membrane from insulin-responsive vesicles. Muscle is the primary site for dietary glucose deposition; however, how GLUT4 sorts into insulin-responsive vesicles, and if and how insulin resistance affects this process, is unknown. In L6 myoblasts stably expressing myc-tagged GLUT4, we analyzed the intracellular itinerary of GLUT4 as it internalizes from the cell surface and examined if such sorting is perturbed by C2-ceramide, a lipid metabolite causing insulin resistance. Surface-labeled GLUT4myc that internalized for 30 min accumulated in a Syntaxin-6 (Stx6)- and Stx16-positive perinuclear sub-compartment devoid of furin or internalized transferrin, and displayed insulin-responsive re-exocytosis. C2-ceramide dispersed the Stx6-positive sub-compartment and prevented insulin-responsive re-exocytosis of internalized GLUT4myc, even under conditions not affecting insulin-stimulated signaling towards Akt. Microtubule disruption with nocodazole prevented pre-internalized GLUT4myc from reaching the Stx6-positive perinuclear sub-compartment and from undergoing insulin-responsive exocytosis. Removing nocodazole allowed both parameters to recover, suggesting that the Stx6-positive perinuclear sub-compartment was required for GLUT4 insulin-responsiveness. Accordingly, Stx6 knockdown inhibited by ∼50% the ability of internalized GLUT4myc to undergo insulin-responsive re-exocytosis without altering its overall perinuclear accumulation. We propose that Stx6 defines the insulin-responsive compartment in muscle cells. Our data are consistent with a model where ceramide could cause insulin resistance by altering intracellular GLUT4 sorting. PMID:24705014

  1. Dynamics of Soil Deflation Features in Kangerlussuaq, Greenland Revealed by Variations in Lichen Diameters on Exposed Surfaces

    NASA Astrophysics Data System (ADS)

    Heindel, R. C.; Kelly, M. A.; Virginia, R. A.

    2013-12-01

    Little is known about the pervasive soil deflation features in the Kangerlussuaq region, West Greenland, an area deglaciated between ~6,800 and 150 years ago. While the majority of the landscape is vegetated with low-lying shrubs and graminoids, wind erosion has removed loess and vegetation from distinct patches ranging in size from a few to tens of meters across, leaving the underlying glacial till or bedrock exposed. Although previous work has considered aeolian landforms and regional loess deposition along the Watson River Valley, these deflation features have not been investigated in detail. We aim to determine both the timing and mechanisms of formation of the deflation features and will examine whether these mechanisms were related to regional climatic conditions, such as increased aridity, to fluctuations in the Greenland Ice Sheet, or to other factors. Our ongoing research investigating these features includes geomorphic mapping using field observations and satellite imagery, lichenometry of the exposed surfaces, and cosmogenic nuclide dating of boulders and bedrock within and near the deflation features. Here we present initial results from our lichenometry studies. During the summer of 2013, we measured maximum lichen (Rhizocarpon sp.) diameters on boulder and bedrock surfaces in 15 soil deflation features located between Kangerlussuaq and the ice sheet margin. Lichen diameters vary from only a few millimeters at the outer margins of deflation features to multiple centimeters (maximum ~50 mm) in the centers of the unvegetated patches. This distinct pattern suggests that the outer margins of the soil deflation features are currently active. Based on a previously established lichen growth curve for Rhizocarpon sp. in West Greenland, our results indicate that the features are expanding at a rate of ~1.5 m per 100 yrs. In addition, the large lichen diameters (~40-50 mm) that occur in the centers of deflation features suggest that the formation mechanism has

  2. Deep crescentic features caused by subglacial boulder point pressure on jointed rock; an example from Virkisjökull, SE Iceland

    NASA Astrophysics Data System (ADS)

    Krabbendam, M.; Bradwell, T.; Everest, J.

    2012-04-01

    A variety of subglacially formed, erosional crescentic features (e.g. crescentic gouges, lunate fractures) have been widely reported on deglaciated bedrock surfaces. They are characterised by a conchoidal fracture that dips in the same direction as the palaeo-ice flow direction, and a steeper fracture that faces against the ice flow. They are generally interpreted as being formed by point pressure exerted by large boulders entrained in basal ice. They are significant in that they record palaeo-ice flow even if shallower glacial striae are obliterated by post-glacial weathering [1, 2, 3]. This contribution reports on deep scallop-shaped, crescentic depressions observed on abraded surfaces of roche moutonnées and whalebacks recently (<10yrs) exposed beneath the actively retreating Virkisjökull, an outlet glacier of the Oraefajökull ice cap in southeast Iceland. The substrate comprises hard rhyolitic rock (relatively rare in Iceland compared to more common basalt and hyaloclastite) with polygonal, columnar jointing. The crescentic depressions at Virkisjökull are cut into smoothed, abraded surfaces festooned with abundant glacial striae. Differences with previously reported crescentic features are: • The scallop-shaped depressions are considerably deeper (5-20 cm); • The steep fracture facing ice flow coincides in all cases with a pre-existing joint that cuts the entire whaleback. The steep joints developed thus before the conchoidal fracture, whilst in reported crescentic features they develop after the conchoidal fracture. We suggest the following formation mechanism. A boulder encased in basal ice exerts continuous pressure on its contact point as it moves across the ice-bedrock contact. This sets up a stress field in the bedrock that does not necessarily exceed the intact rock strength (other crescentic features are rare to absent at Virkisjökull). However, as the stress field migrates (with the transported boulder) and encounters a subvertical, pre

  3. Diversity and dynamics of algal Megaviridae members during a harmful brown tide caused by the pelagophyte, Aureococcus anophagefferens.

    PubMed

    Moniruzzaman, Mohammad; Gann, Eric R; LeCleir, Gary R; Kang, Yoonja; Gobler, Christopher J; Wilhelm, Steven W

    2016-05-01

    Many giant dsDNA algal viruses share a common ancestor with Mimivirus--one of the largest viruses, in terms of genetic content. Together, these viruses form the proposed 'Megaviridae' clade of nucleocytoplasmic large DNA viruses. To gauge Megaviridae diversity, we designed degenerate primers targeting the major capsid protein genes of algae-infecting viruses within this group and probed the clade's diversity during the course of a brown tide bloom caused by the harmful pelagophyte,Aureococcus anophagefferens We amplified target sequences in water samples from two distinct locations (Weesuck Creek and Quantuck Bay, NY) covering 12 weeks concurrent with the proliferation and demise of a bloom. In total, 475 amplicons clustered into 145 operational taxonomic units (OTUs) at 97% identity. One OTU contained 19 sequences with ≥97% identity to AaV, a member of the Megaviridae clade that infects A. anophagefferens, suggesting AaV was present during the bloom. Unifrac analysis showed clear temporal patterns in algal Megaviridae dynamics, with a shift in the virus community structure that corresponded to the Aureococcus bloom decline in both locations. Our data provide insights regarding the environmental relevance of algal Megaviridae members and raise important questions regarding their phylodynamics across different environmental gradients. PMID:26985013

  4. Evolutionary and Ecological Dynamics of Transboundary Disease Caused by H5N1 Virus in Southeast Asia.

    PubMed

    Wei, K; Lin, Y; Xie, D

    2015-06-01

    Southeast Asia has been the breeding ground for many emerging diseases in the past decade, and it is in this region that new genetic variants of HPAI H5N1 viruses have been emerging. Cross-border movement of animals accelerates the spread of H5N1, and the changing environmental conditions also exert strong selective pressure on the viruses. The transboundary zoonotic diseases caused by H5N1 pose a serious and continual threat to global economy and public health. Here, we divided the H5N1 viruses isolated in Southeast Asia during 2003-2009 into four groups according to their phylogenetic relationships among HA gene sequences. Molecular evolution analysis suggests populations in expansion rather than a positive selection for group 2 and group 3, yet group 4 is under strong positive selection. Site 193 was found to be a potential glycosylation site and located in receptor-binding domain. Note that site 193 tends to appear in avian isolates instead of human strains. Population dynamics analysis reveals that the effective population size of infections in Southeast Asia has undergone three obvious increases, and the results are consistent with the epidemiological analysis. Ecological and phylogeographical analyses show that agro-ecological environments, migratory birds, domestic waterfowl, especially free-ranging ducks, are crucial in the occurrence, maintenance and spread of H5N1 virus. The epidemiological links between Indonesia and Suphanburi observed suggest that viruses in Indonesia were originated from multiple introductions. PMID:23952973

  5. Brine flow up a borehole caused by pressure perturbation from CO2 storage: Static and dynamic evaluations

    SciTech Connect

    Birkholzer, J.T.; Nicot, J.-P.; Oldenburg, C.M.; Zhou, Q.; Kraemer, S.; Bandilla, K.W.

    2011-05-01

    Industrial-scale storage of CO{sub 2} in saline sedimentary basins will cause zones of elevated pressure, larger than the CO{sub 2} plume itself. If permeable conduits (e.g., leaking wells) exist between the injection reservoir and overlying shallow aquifers, brine could be pushed upwards along these conduits and mix with groundwater resources. This paper discusses the potential for such brine leakage to occur in temperature- and salinity-stratified systems. Using static mass-balance calculations as well as dynamic well flow simulations, we evaluate the minimum reservoir pressure that would generate continuous migration of brine up a leaking wellbore into a freshwater aquifer. Since the brine invading the well is denser than the initial fluid in the wellbore, continuous flow only occurs if the pressure perturbation in the reservoir is large enough to overcome the increased fluid column weight after full invasion of brine into the well. If the threshold pressure is exceeded, brine flow rates are dependent on various hydraulic (and other) properties, in particular the effective permeability of the wellbore and the magnitude of pressure increase. If brine flow occurs outside of the well casing, e.g., in a permeable fracture zone between the well cement and the formation, the fluid/solute transfer between the migrating fluid and the surrounding rock units can strongly retard brine flow. At the same time, the threshold pressure for continuous flow to occur decreases compared to a case with no fluid/solute transfer.

  6. E-photosynthesis: a comprehensive modeling approach to understand chlorophyll fluorescence transients and other complex dynamic features of photosynthesis in fluctuating light.

    PubMed

    Nedbal, Ladislav; Cervený, Jan; Rascher, Uwe; Schmidt, Henning

    2007-01-01

    Plants are exposed to a temporally and spatially heterogeneous environment, and photosynthesis is well adapted to these fluctuations. Understanding of the complex, non-linear dynamics of photosynthesis in fluctuating light requires novel-modeling approaches that involve not only the primary light and dark biochemical reactions, but also networks of regulatory interactions. This requirement exceeds the capacity of the existing molecular models that are typically reduced to describe a partial process, dynamics of a specific complex or its particular dynamic feature. We propose a concept of comprehensive model that would represent an internally consistent, integral framework combining information on the reduced models that led to its construction. This review explores approaches and tools that exist in engineering, mathematics, and in other domains of biology that can be used to develop a comprehensive model of photosynthesis. Equally important, we investigated techniques by which one can rigorously reduce such a comprehensive model to models of low dimensionality, which preserve dynamic features of interest and, thus, contribute to a better understanding of photosynthesis under natural and thus fluctuating conditions. The web-based platform www.e-photosynthesis.org is introduced as an arena where these concepts and tools are being introduced and tested. PMID:17492490

  7. Missense variant in CCDC22 causes X-linked recessive intellectual disability with features of Ritscher-Schinzel/3C syndrome

    PubMed Central

    Kolanczyk, Mateusz; Krawitz, Peter; Hecht, Jochen; Hupalowska, Anna; Miaczynska, Marta; Marschner, Katrin; Schlack, Claire; Emmerich, Denise; Kobus, Karolina; Kornak, Uwe; Robinson, Peter N; Plecko, Barbara; Grangl, Gernot; Uhrig, Sabine; Mundlos, Stefan; Horn, Denise

    2015-01-01

    Ritscher-Schinzel syndrome (RSS)/3C (cranio-cerebro-cardiac) syndrome (OMIM#220210) is a rare and clinically heterogeneous developmental disorder characterized by intellectual disability, cerebellar brain malformations, congenital heart defects, and craniofacial abnormalities. A recent study of a Canadian cohort identified homozygous sequence variants in the KIAA0196 gene, which encodes the WASH complex subunit strumpellin, as a cause for a form of RSS/3C syndrome. We have searched for genetic causes of a phenotype similar to RSS/3C syndrome in an Austrian family with two affected sons. To search for disease-causing variants, whole-exome sequencing (WES) was performed on samples from two affected male children and their parents. Before WES, CGH array comparative genomic hybridization was applied. Validation of WES and segregation studies was done using routine Sanger sequencing. Exome sequencing detected a missense variant (c.1670A>G; p.(Tyr557Cys)) in exon 15 of the CCDC22 gene, which maps to chromosome Xp11.23. Western blots of immortalized lymphoblastoid cell lines (LCLs) from the affected individual showed decreased expression of CCDC22 and an increased expression of WASH1 but a normal expression of strumpellin and FAM21 in the patients cells. We identified a variant in CCDC22 gene as the cause of an X-linked phenotype similar to RSS/3C syndrome in the family described here. A hypomorphic variant in CCDC22 was previously reported in association with a familial case of syndromic X-linked intellectual disability, which shows phenotypic overlap with RSS/3C syndrome. Thus, different inactivating variants affecting CCDC22 are associated with a phenotype similar to RSS/3C syndrome. PMID:24916641

  8. Cervical canal stenosis caused by progressive fusion and enlargement of cervical vertebrae with features of Proteus syndrome and Klippel-Feil syndrome.

    PubMed

    Sugita, Shurei; Chikuda, Hirotaka; Ohya, Junichi; Taniguchi, Yuki; Takeshita, Katsushi; Haga, Nobuhiko; Ushiku, Tetsuo; Tanaka, Sakae

    2013-12-01

    We report the case of a female who presented with progressive fusion and an enlargement of the cervical vertebrae. Her cervical deformity gradually progressed with age, and the abnormal bony protrusion into the spinal canal caused myelopathy. We resected the affected vertebrae to decompress the spinal cord and performed combined anterior-posterior spinal fusion. The progression of the spinal deformity and enlargement of vertebrae stopped after surgery. The enlargement of vertebrae in the present case resembled that observed in Proteus syndrome; however, autonomous vertebral fusion has not been reported previously in patients with this condition. Our report may help expand the knowledge on developmental spine disorders. PMID:23760594

  9. Seasonal Dynamics of Hyperspectral Reflectance Patterns Influencing Detection of Imported Fire Ant (Hymenoptera: Formicidae) Mound Features in Turfgrass

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Invasive mound-building imported fire ants impact soil quality and turfgrass nutrient management affecting an estimated 8.1 million hectares in sod production, recreational, and residential settings in the southeastern U.S. Reflectance characteristics of imported fire ant mound features (i.e., ant m...

  10. Extremely Selective Attention: Eye-Tracking Studies of the Dynamic Allocation of Attention to Stimulus Features in Categorization

    ERIC Educational Resources Information Center

    Blair, Mark R.; Watson, Marcus R.; Walshe, R. Calen; Maj, Fillip

    2009-01-01

    Humans have an extremely flexible ability to categorize regularities in their environment, in part because of attentional systems that allow them to focus on important perceptual information. In formal theories of categorization, attention is typically modeled with weights that selectively bias the processing of stimulus features. These theories…

  11. Geographic Variations in Hotspot Geochemistry Caused by 3D Dynamics and Melting of a Heterogeneous Mantle Plume

    NASA Astrophysics Data System (ADS)

    Bianco, T. A.; Ito, G.; van Hunen, J.; Ballmer, M.; Mahoney, J. J.

    2006-12-01

    Spatial variations in magma geochemistry among hotspot volcanoes hold clues to the dynamics and composition of the mantle feeding hotspot volcanism. We use a 3D geodynamic model of plume-lithosphere interaction to explore the causes of spatial patterns of magmatic volumes and compositions at intraplate hotspots. This study focuses on coupling between upper mantle flow, heat transfer, and melting of a heterogeneous (veined) plume. We assume multiple lithologies have different solidi, trace-element, and isotope composition. We use the Cartesian finite-element code, CITCOM, (Zhong and Watts, 2002) to simulate mantle convection with the extended Boussinesq approximation in a volume of upper mantle 400 km in thickness. A parameterized melting model is used to simulate melting of materials with different water contents (Katz et al., 2003). Melt depletion (F) for each lithology is calculated at finite element nodes as a function of temperature, pressure, and water content and is advected using particle tracers. We quantify the response of the geographic pattern of the volume and composition of magmas to different lithospheric thicknesses, and plume temperatures and viscosities, which together control the melting rates and sizes of the melting zones for the different lithologies. In the case of two-lithologies, preliminary results of a sluggishly convecting plume rising beneath thick lithosphere (60-100 km) predict that the melting zone of the least refractory "lithology 1" is wider than that of the more refractory "lithology 2". This leads to the prediction that on the surface, the isotope signature of lithology 1 is most prominent at the leading edge (i.e., upwind edge of plate motion) of the hotspot, whereas the isotope signature of lithology 2 is strongest at the hotspot center. This pattern will likely change for plumes convecting more vigorously or thinner lithosphere.

  12. Identification of Molecular Pathologies Sufficient to Cause Neuropathic Excitability in Primary Somatosensory Afferents Using Dynamical Systems Theory

    PubMed Central

    Rho, Young-Ah; Prescott, Steven A.

    2012-01-01

    Pain caused by nerve injury (i.e. neuropathic pain) is associated with development of neuronal hyperexcitability at several points along the pain pathway. Within primary afferents, numerous injury-induced changes have been identified but it remains unclear which molecular changes are necessary and sufficient to explain cellular hyperexcitability. To investigate this, we built computational models that reproduce the switch from a normal spiking pattern characterized by a single spike at the onset of depolarization to a neuropathic one characterized by repetitive spiking throughout depolarization. Parameter changes that were sufficient to switch the spiking pattern also enabled membrane potential oscillations and bursting, suggesting that all three pathological changes are mechanistically linked. Dynamical analysis confirmed this prediction by showing that excitability changes co-develop when the nonlinear mechanism responsible for spike initiation switches from a quasi-separatrix-crossing to a subcritical Hopf bifurcation. This switch stems from biophysical changes that bias competition between oppositely directed fast- and slow-activating conductances operating at subthreshold potentials. Competition between activation and inactivation of a single conductance can be similarly biased with equivalent consequences for excitability. “Bias” can arise from a multitude of molecular changes occurring alone or in combination; in the latter case, changes can add or offset one another. Thus, our results identify pathological change in the nonlinear interaction between processes affecting spike initiation as the critical determinant of how simple injury-induced changes at the molecular level manifest complex excitability changes at the cellular level. We demonstrate that multiple distinct molecular changes are sufficient to produce neuropathic changes in excitability; however, given that nerve injury elicits numerous molecular changes that may be individually sufficient to

  13. Population Dynamics of Aphids on Cereals: Digging in the Time-Series Data to Reveal Population Regulation Caused by Temperature

    PubMed Central

    Brabec, Marek; Honěk, Alois; Pekár, Stano; Martinková, Zdenka

    2014-01-01

    Aphid populations show periodic fluctuations and many causes are attributed to their dynamic. We investigated the regulation by temperature of the aphid populations composed of Metopolophium dirhodum, Sitobion avenae, and Rhopalosiphum padi on winter wheat using a 24 years long time series data. We computed the sum of daily temperatures above 5°C, the threshold temperature for aphid development, and the sum of daily temperatures within the [0(threshold for wheat development),5] °C interval. Applying Generalised Additive Model framework we tested influences of temperature history expressed via degree days before the start of the aphid immigration on the length of their occurrence. We aimed to estimate the magnitude and direction of this influence, and how far to the past before the start of the aphid season the temperature effect goes and then identify processes responsible for the effect. We fitted four models that differed in the way of correcting for abundance in the previous year and in specification of temperature effects. Abundance in the previous year did not affect the length of period of aphid population growth on wheat. The temperature effect on the period length increased up to 123 days before the start of the current season, i.e. when wheat completed vernalization. Increased sum of daily temperatures above 5°C and the sum of daily temperatures within the [0,5] °C interval both shortened the length of period of aphid population growth. Stronger effect of the latter suggests that wheat can escape from aphid attacks if during winter temperatures range from 0 to 5°C. The temperature influence was not homogeneous in time. The strongest effect of past temperature was about 50 to 80 and 90 to 110 days before the beginning of the current aphid season indicating important role of termination of aphid egg dormancy and egg hatching. PMID:25184219

  14. Dynamics of speckles with a small number of scattering events: specific features of manifestation of the Doppler effect.

    PubMed

    Ulyanov, Sergey S

    2014-04-01

    Spectra of intensity fluctuations of dynamic non-Gaussian speckles formed with a small number of scattering events have been studied theoretically and experimentally. A new type of manifestation of the Doppler effect has been observed. The dependence of frequency position of the Doppler peak and the shape of the Doppler spectrum on the number of scatterers has been analyzed. PMID:24787223

  15. TGFB2 loss of function mutations cause familial thoracic aortic aneurysms and acute aortic dissections associated with mild systemic features of the Marfan syndrome

    PubMed Central

    Boileau, Catherine; Guo, Dong-Chuan; Hanna, Nadine; Regalado, Ellen S.; Detaint, Delphine; Gong, Limin; Varret, Mathilde; Prakash, Siddharth; Li, Alexander H.; d’Indy, Hyacintha; Braverman, Alan C.; Grandchamp, Bernard; Kwartler, Callie S.; Gouya, Laurent; Santos-Cortez, Regie Lyn P.; Abifadel, Marianne; Leal, Suzanne M.; Muti, Christine; Shendure, Jay; Gross, Marie-Sylvie; Rieder, Mark J.; Vahanian, Alec; Nickerson, Deborah A.; Michel, Jean Baptiste; Jondeau, Guillaume; Milewicz, Dianna M.

    2014-01-01

    A predisposition for thoracic aortic aneurysms leading to acute aortic dissections can be inherited in families in an autosomal dominant manner. Genome-wide linkage analysis of two large unrelated families with thoracic aortic disease, followed by whole exome sequencing of affected relatives, identified causative mutations in TGFB2. These mutations, a frameshift mutation in exon 6 and a nonsense mutation in exon 4, segregated with disease with a combined LOD score of 7.7. Sanger sequencing of 276 probands from families with inherited thoracic aortic disease identified two additional TGFB2 mutations. TGFB2 encodes the transforming growth factor beta-2 (TGF-β2) and the mutations are predicted to cause haploinsufficiency for TGFB2, but aortic tissue from cases paradoxically shows increased TGF-β2 expression and immunostaining. Thus, haploinsufficiency of TGFB2 predisposes to thoracic aortic disease, suggesting the initial pathway driving disease is decreased cellular TGF-β2 levels leading to a secondary increase in TGF-β2 production in the diseased aorta. PMID:22772371

  16. Toxic epidermal necrolysis caused by acetaminophen featuring almost 100% skin detachment: Acetaminophen is associated with a risk of severe cutaneous adverse reactions.

    PubMed

    Watanabe, Hideaki; Kamiyama, Taisuke; Sasaki, Shun; Kobayashi, Kae; Fukuda, Kenichiro; Miyake, Yasufumi; Aruga, Tohru; Sueki, Hirohiko

    2016-03-01

    Toxic epidermal necrolysis (TEN) is an adverse reaction that can be induced by various drugs; the associated mortality rate is 20-25%. A previous report showed a weak association between TEN and acetaminophen. Recently, the US Food and Drug Administration declared that acetaminophen is associated with a risk of serious skin reactions, including TEN. Here, we describe the case of a 43-year-old Japanese woman with TEN caused by acetaminophen. She had poorly controlled ulcerative colitis and was treated with high doses of prednisolone, infliximab, acetaminophen and lansoprazole. Nine days after administrating acetaminophen, targetoid erythematous and bullous lesions appeared on the patient's trunk, palms and the soles of her feet. The skin lesions expanded rapidly; within 3 weeks, skin detachment was detected across nearly 100% of the patient's body. However, no mucosal involvement of the eyes, oral cavity or genitalia was found. We performed lymphocyte transformation tests using various drugs; however, a high stimulation index was obtained only with acetaminophen. The patient recovered following treatment with plasmapheresis, i.v. immunoglobulin therapy, topical medication and supportive therapy. Acetaminophen is included in many prescription and over-the-counter products; thus, clinicians should monitor their patients for severe drug reactions, including TEN. PMID:26362011

  17. Compressed exponential relaxation in liquid silicon: Universal feature of the crossover from ballistic to diffusive behavior in single-particle dynamics

    NASA Astrophysics Data System (ADS)

    Morishita, Tetsuya

    2012-07-01

    We report a first-principles molecular-dynamics study of the relaxation dynamics in liquid silicon (l-Si) over a wide temperature range (1000-2200 K). We find that the intermediate scattering function for l-Si exhibits a compressed exponential decay above 1200 K including the supercooled regime, which is in stark contrast to that for normal "dense" liquids which typically show stretched exponential decay in the supercooled regime. The coexistence of particles having ballistic-like motion and those having diffusive-like motion is demonstrated, which accounts for the compressed exponential decay in l-Si. An attempt to elucidate the crossover from the ballistic to the diffusive regime in the "time-dependent" diffusion coefficient is made and the temperature-independent universal feature of the crossover is disclosed.

  18. Causes, Dynamics and Impacts of Lahar Mass Flows due to the April 2015 Eruption of Calbuco Volcano, Chile

    NASA Astrophysics Data System (ADS)

    Dussaillant, Alejandro; Russell, Andy; Meier, Claudio; Rivera, Andres; Mella, Mauricio; Garrido, Natalia; Hernandez, Jorge; Napoleoni, Felipe; Gonzalez, Cristian

    2016-04-01

    Calbuco is a 2015m high, glacier capped, stratovolcano in the heavily populated Los Lagos region of southern Chile with a history of large volcanic eruptions in 1893-95, 1906-7, 1911-12, 1917, 1932, 1945, 1961 and 1972. Calbuco volcano experienced a powerful 90 minute eruption at 18:04h on 22 April, 2015 followed by additional major eruptions at 01:00h and 13:10h on 23 & 30 April, respectively, resulting in the evacuation of 6500 people and the imposition of a 20 km radius exclusion zone. Pyroclastic flows descended into several river catchments radiating from the volcano with lahars travelling distances of up to 14 km, reaching populated areas. We present findings from detailed field observations from April and July 2015, and January 2016, regarding the causes, dynamics and impacts of lahars generated by the April 2015 eruption, supported by satellite imagery, LiDAR and detailed rtkGPS & TLS surveys, as well as sediment sampling. Pyroclastic flows melted glacier ice and snow generating the largest lahars in the Rio Este and Rio Blanco Sur on the southern flanks of the volcano. Lahar deposits in the Rio Blanco Norte were buried by pyroclastic flow deposits with measured temperatures of up to 282°C three months after emplacement. Lahar erosional impacts included bedrock erosion, alluvial channel incision, erosion of surficial deposits and the felling of large areas of forest. Depositional landforms included boulder run-ups on the outsides of channel bends, boulder clusters and large woody debris jams. Lahars deposited up to 8m of sediment within distal reaches. Deposits on the southern flanks of Calbuco indicate the passage of multiple pulses of contrasting rheology. Lahar occurrence and magnitude was controlled by the pre-eruption distribution of snow and ice on the volcano. Pre-existing lahar channels controlled flows to lower piedmont zones where routing was determined by palaeo-lahar geomorphology. Ongoing erosion of proximal pyroclastic flow and lahar deposits

  19. De Novo Loss-of-Function Mutations in CHD2 Cause a Fever-Sensitive Myoclonic Epileptic Encephalopathy Sharing Features with Dravet Syndrome

    PubMed Central

    Suls, Arvid; Jaehn, Johanna A.; Kecskés, Angela; Weber, Yvonne; Weckhuysen, Sarah; Craiu, Dana C.; Siekierska, Aleksandra; Djémié, Tania; Afrikanova, Tatiana; Gormley, Padhraig; von Spiczak, Sarah; Kluger, Gerhard; Iliescu, Catrinel M.; Talvik, Tiina; Talvik, Inga; Meral, Cihan; Caglayan, Hande S.; Giraldez, Beatriz G.; Serratosa, José; Lemke, Johannes R.; Hoffman-Zacharska, Dorota; Szczepanik, Elzbieta; Barisic, Nina; Komarek, Vladimir; Hjalgrim, Helle; Møller, Rikke S.; Linnankivi, Tarja; Dimova, Petia; Striano, Pasquale; Zara, Federico; Marini, Carla; Guerrini, Renzo; Depienne, Christel; Baulac, Stéphanie; Kuhlenbäumer, Gregor; Crawford, Alexander D.; Lehesjoki, Anna-Elina; de Witte, Peter A.M.; Palotie, Aarno; Lerche, Holger; Esguerra, Camila V.; De Jonghe, Peter; Helbig, Ingo; Hendrickx, Rik; Holmgren, Philip; Stephani, Ulrich; Muhle, Hiltrud; Pendiziwiat, Manuela; Appenzeller, Silke; Selmer, Kaja; Brilstra, Eva; Koeleman, Bobby; Rosenow, Felix; Leguern, Eric; Sterbova, Katalin; Magdalena, Budisteanu; Rodica, Gherghiceanu; Arsene, Oana Tarta; Diana, Barca; Guerrero-Lopez, Rosa; Ortega, Laura; Todorova, Albena P.; Kirov, Andrey V.; Robbiano, Angela; Arslan, Mutluay; Yiş, Uluç; Ivanović, Vanja

    2013-01-01

    Dravet syndrome is a severe epilepsy syndrome characterized by infantile onset of therapy-resistant, fever-sensitive seizures followed by cognitive decline. Mutations in SCN1A explain about 75% of cases with Dravet syndrome; 90% of these mutations arise de novo. We studied a cohort of nine Dravet-syndrome-affected individuals without an SCN1A mutation (these included some atypical cases with onset at up to 2 years of age) by using whole-exome sequencing in proband-parent trios. In two individuals, we identified a de novo loss-of-function mutation in CHD2 (encoding chromodomain helicase DNA binding protein 2). A third CHD2 mutation was identified in an epileptic proband of a second (stage 2) cohort. All three individuals with a CHD2 mutation had intellectual disability and fever-sensitive generalized seizures, as well as prominent myoclonic seizures starting in the second year of life or later. To explore the functional relevance of CHD2 haploinsufficiency in an in vivo model system, we knocked down chd2 in zebrafish by using targeted morpholino antisense oligomers. chd2-knockdown larvae exhibited altered locomotor activity, and the epileptic nature of this seizure-like behavior was confirmed by field-potential recordings that revealed epileptiform discharges similar to seizures in affected persons. Both altered locomotor activity and epileptiform discharges were absent in appropriate control larvae. Our study provides evidence that de novo loss-of-function mutations in CHD2 are a cause of epileptic encephalopathy with generalized seizures. PMID:24207121

  20. Features of the behavior of solutions to a nonlinear dynamical system in the case of two-frequency parametric resonance

    NASA Astrophysics Data System (ADS)

    Koverga, A. Yu.; Kubyshkin, E. P.

    2013-05-01

    Two-frequency parametric resonance in nonlinear dynamical systems is studied by analyzing a delay differential equation with the delay obeying a two-frequency law, which arises in the mathematical simulation of some physical processes. It is shown that the system can exhibit chaotic oscillations (strange attractors) when the parametric excitation frequencies are both close to the doubled eigenfrequency of the system (degenerate case). The formation mechanisms of chaotic attractors are discussed, and the Lyapunov exponents and the Lyapunov dimension are calculated for them. If only one of the parametric excitation frequencies is close to the double eigenfrequency, a two-frequency regime occurs in the system.

  1. Special Features of the Structure of Secular Resonances in the Dynamics of Near-Earth Space Objects

    NASA Astrophysics Data System (ADS)

    Bordovitsyna, T. V.; Tomilova, I. V.

    2016-07-01

    The special features of the structure of secular resonances in the near-earth orbital space bounded by the following range of orbital parameters: semimajor axis from 8000 to 55 000 km, inclination from 0 to 90°, and eccentricity equal to 0.01, 0.6, and 0.8 are analyzed. The influence of stable and unstable secular resonances on the long-term orbital evolution of near-earth space objects is also considered. It is demonstrated that the joint effect of the stable secular resonances of different spectral classes does not violate the regularity of motion. The chaoticity arises when stable secular resonances of one spectral class are imposed.

  2. Curvature effects on the adsorption of aqueous sodium-dodecyl-sulfate surfactants on carbonaceous substrates: Structural features and counterion dynamics

    NASA Astrophysics Data System (ADS)

    Tummala, Naga Rajesh; Striolo, Alberto

    2009-08-01

    The effect of substrate curvature on surfactant self-assembly has been studied using all-atom molecular-dynamics simulations. We studied aqueous sodium-dodecyl-sulfate (SDS) surfactants on graphite, on the outer surface of single walled carbon nanotubes (SWNTs) and within SWNTs. Our results reveal that although the chemical nature of the substrates is constant, the self-assembled structures change significantly as the curvature varies. For example, at large surface density, SDS surfactants yield micellar structures on graphite, layered self-assemblies outside SWNTs, and cylindrical lamellar structures inside SWNTs. Changes in substrate curvature as well as surfactant surface density affect significantly surfactant orientation and, more importantly, headgroup-headgroup distribution, headgroup-counterion packing, and counterion residence time next to the headgroups.

  3. Specific features of low-frequency vibrational dynamics and low-temperature heat capacity of double-walled carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Avramenko, M. V.; Roshal, S. B.

    2016-05-01

    A continuous model has been constructed for low-frequency dynamics of a double-walled carbon nanotube. The formation of the low-frequency part of the phonon spectrum of a double-walled nanotube from phonon spectra of its constituent single-walled nanotubes has been considered in the framework of the proposed approach. The influence of the environment on the phonon spectrum of a single double-walled carbon nanotube has been analyzed. A combined method has been proposed for estimating the coefficients of the van der Waals interaction between the walls of the nanotube from the spectroscopic data and the known values of the elastic moduli of graphite. The low-temperature specific heat has been calculated for doublewalled carbon nanotubes, which in the field of applicability of the model ( T < 35 K) is substantially less than the sum of specific heats of two individual single-walled nanotubes forming it.

  4. Emotional Intolerance and Core Features of Anorexia Nervosa: A Dynamic Interaction during Inpatient Treatment? Results from a Longitudinal Diary Study

    PubMed Central

    Stroe-Kunold, Esther; Friederich, Hans-Christoph; Stadnitski, Tatjana; Wesche, Daniela; Herzog, Wolfgang; Schwab, Michael; Wild, Beate

    2016-01-01

    Objective The role of emotion dysregulation with regard to the psychopathology of anorexia nervosa (AN) is increasingly discussed. It is both assumed that AN symptoms have an impact on difficulties in tolerating aversive emotions and that—conversely—emotion dysregulation influences AN. To date, such conclusions are drawn on the basis of cross-sectional data not allowing for inferences on the temporal dynamics. The current study investigates the longitudinal interaction between emotional intolerance and core AN symptoms over the course of inpatient treatment by comparing patients with high (BMI<15 kg/m2) vs. low symptom severity (HSS vs. LSS). Method The study adopted a longitudinal, process-oriented design with N = 16 analysed electronic diaries. Throughout the course of their inpatient treatment, the patients answered questions daily about emotional intolerance and their AN-specific cognitions and behaviours. The temporal dynamics between emotional intolerance and these variables were analysed using a multivariate time series approach. Results The time series of the processes under investigation adequately reflected the individual treatment courses. The majority of significant linear time trends was found for HSS patients. Most importantly, analysis revealed significant temporal interactions between emotional intolerance and AN symptoms in almost 70% of HSS patients. Thereby, up to 37% of variance in eating restraint and up to 23% in weight concern could be attributed to changes in emotional intolerance. Conclusions The findings support the notion that intolerable unpleasant emotions in severely affected AN patients influence their psychopathology. Additionally, time series analysis outlined the inter-individual heterogeneity of psychosomatic treatment courses of AN patients. PMID:27191959

  5. An Effective Approach for Clustering InhA Molecular Dynamics Trajectory Using Substrate-Binding Cavity Features.

    PubMed

    De Paris, Renata; Quevedo, Christian V; Ruiz, Duncan D A; Norberto de Souza, Osmar

    2015-01-01

    Protein receptor conformations, obtained from molecular dynamics (MD) simulations, have become a promising treatment of its explicit flexibility in molecular docking experiments applied to drug discovery and development. However, incorporating the entire ensemble of MD conformations in docking experiments to screen large candidate compound libraries is currently an unfeasible task. Clustering algorithms have been widely used as a means to reduce such ensembles to a manageable size. Most studies investigate different algorithms using pairwise Root-Mean Square Deviation (RMSD) values for all, or part of the MD conformations. Nevertheless, the RMSD only may not be the most appropriate gauge to cluster conformations when the target receptor has a plastic active site, since they are influenced by changes that occur on other parts of the structure. Hence, we have applied two partitioning methods (k-means and k-medoids) and four agglomerative hierarchical methods (Complete linkage, Ward's, Unweighted Pair Group Method and Weighted Pair Group Method) to analyze and compare the quality of partitions between a data set composed of properties from an enzyme receptor substrate-binding cavity and two data sets created using different RMSD approaches. Ensembles of representative MD conformations were generated by selecting a medoid of each group from all partitions analyzed. We investigated the performance of our new method for evaluating binding conformation of drug candidates to the InhA enzyme, which were performed by cross-docking experiments between a 20 ns MD trajectory and 20 different ligands. Statistical analyses showed that the novel ensemble, which is represented by only 0.48% of the MD conformations, was able to reproduce 75% of all dynamic behaviors within the binding cavity for the docking experiments performed. Moreover, this new approach not only outperforms the other two RMSD-clustering solutions, but it also shows to be a promising strategy to distill

  6. Effects of temperature, particle features and vent geometry on volcanic jet dynamics, a shock-tube investigation.

    NASA Astrophysics Data System (ADS)

    Cigala, Valeria; Kueppers, Ulrich; Dingwell, Donald B.

    2016-04-01

    The lowermost part of an eruptive plume commonly shows characteristics of an underexpanded jet. The dynamics of this gas-thrust region are likely to be a direct consequence of intrinsic (magma properties, overpressure) and extrinsic (vent geometry, weather) eruption conditions. Additionally, they affect the subsequent evolution of the eruptive column and have, therefore, important hazard assessment implications for both near- and far-field. Direct observation of eruptive events is possible, but often insufficient for complete characterization. Important complementary data can be achieved using controlled and calibrated laboratory experiments. Loose natural particles were ejected from a shock-tube while controlling temperature (25° and 500°C), overpressure (15MPa), starting grain size distribution (1-2 mm, 0.5-1 mm and 0.125-0.250 mm), density (basaltic and phonolitic), gas-particle ratio and vent geometry (nozzle, cylindrical, funnel with a flaring of 15° and 30°, respectively). For each experiment, we quantified the velocity of individual particles, the jet spreading angle, the presence of electric discharges and the production of fines and analysed their dynamic evolution. Data shows velocity of up to 296 m/s and deceleration patterns following nonlinear paths. Gas spreading angles range between 21° and 41° while the particle spreading angles between 3° and 32°. Electric discharges, in the form of lightning, are observed, quantified and described. Moreover, a variation in the production of fines is recognized during the course of single experiments. This experimental investigation, which mechanistically mimics the process of pyroclast ejection, is shown to be capable of constraining the effects of input parameters and conduit/vent geometry on pyroclastic plumes. Therefore, the results should greatly enhance the ability of numerically model explosive ejecta in nature.

  7. An Effective Approach for Clustering InhA Molecular Dynamics Trajectory Using Substrate-Binding Cavity Features

    PubMed Central

    Ruiz, Duncan D. A.; Norberto de Souza, Osmar

    2015-01-01

    Protein receptor conformations, obtained from molecular dynamics (MD) simulations, have become a promising treatment of its explicit flexibility in molecular docking experiments applied to drug discovery and development. However, incorporating the entire ensemble of MD conformations in docking experiments to screen large candidate compound libraries is currently an unfeasible task. Clustering algorithms have been widely used as a means to reduce such ensembles to a manageable size. Most studies investigate different algorithms using pairwise Root-Mean Square Deviation (RMSD) values for all, or part of the MD conformations. Nevertheless, the RMSD only may not be the most appropriate gauge to cluster conformations when the target receptor has a plastic active site, since they are influenced by changes that occur on other parts of the structure. Hence, we have applied two partitioning methods (k-means and k-medoids) and four agglomerative hierarchical methods (Complete linkage, Ward’s, Unweighted Pair Group Method and Weighted Pair Group Method) to analyze and compare the quality of partitions between a data set composed of properties from an enzyme receptor substrate-binding cavity and two data sets created using different RMSD approaches. Ensembles of representative MD conformations were generated by selecting a medoid of each group from all partitions analyzed. We investigated the performance of our new method for evaluating binding conformation of drug candidates to the InhA enzyme, which were performed by cross-docking experiments between a 20 ns MD trajectory and 20 different ligands. Statistical analyses showed that the novel ensemble, which is represented by only 0.48% of the MD conformations, was able to reproduce 75% of all dynamic behaviors within the binding cavity for the docking experiments performed. Moreover, this new approach not only outperforms the other two RMSD-clustering solutions, but it also shows to be a promising strategy to distill

  8. Slow dynamics in the geometrically frustrated magnet ZnFe2O4: Universal features of aging phenomena in spin glasses

    NASA Astrophysics Data System (ADS)

    Mamiya, H.; Tsujii, N.; Terada, N.; Nimori, S.; Kitazawa, H.; Hoshikawa, A.; Ishigaki, T.

    2014-07-01

    To clarify the universal features of spin glasses, we carefully studied slow dynamics in a geometrically frustrated magnet ZnFe2O4 with slight disorders, regarded as an "unconventional" Heisenberg spin glass, using time-resolved neutron diffractometry and magnetometry. The results indicate that "aging" can be attributed not to growth of the short-range order detected by a diffuse scattering but to aging of a hidden aperiodic correlation, as expected from theories for spin glasses. Concerning aging, peculiar behavior was found; the decay of thermoremanent magnetization is extremely accelerated if the sample is heated/cooled briefly midway through the isothermal slow relaxation. Conversely, magnetization surprisingly increases despite the absence of a magnetic field when the temperature returns after the brief heating/cooling. The behavior can be explained as a destabilization of the aged spin configuration due to the thermal perturbations and subsequent spontaneous restoration of the original spin configuration after the destabilization. Whereas such destabilization and restoration do not occur during freezing into numerous metastable states in a fixed energy landscape, these are possible in an energy landscape with a temperature-sensitive funnel-like structure. These features, consistent with the ghost domain scenario of the droplet picture, are the same as for conventional Heisenberg spin glasses such as dilute magnetic alloys and dilute magnetic semiconductors. In other words, they are universal features in Heisenberg spin glasses including unconventional ones.

  9. A smart dynamic self-induced orientable multiple size nano-roughness with amphiphilic feature as a stain-repellent hydrophilic surface.

    PubMed

    Dastjerdi, Roya; Montazer, Majid; Stegmaier, Thomas; Moghadam, M B

    2012-03-01

    Recently developing bioinspired super-hydrophobic surfaces to achieve self-cleaning properties has been driving numerous researches. However, hydrophilicity is one of the most important features of garment comfort. Therefore, accomplishing self-cleaning and stain repellency on hydrophilic surfaces would be a high topic of interest. This research is concerned with wettability mechanism; static and dynamic study of contact angle through water droplet absorption on the multiple scale nano-roughness covered by different weight ratio of oppositely charged inorganic nanoparticles and amino-functionalized polysiloxane. The results revealed that the second layer of the resin formed on the surface can show an amphiphilic hybrid block copolymer-like feature whose dual action can be intensified during water droplet absorption by the created multiple size nano-roughness. This unique structure can create a stain repellent but hydrophilic surface with exceptional advantages. The mechanism has been deeply discussed according to the evidence on droplet edge interfacial energy changes as a driving force to overcome meta-stable Cassie state on the multiple size nano-roughness with amphiphilic feature. A lotus-like nano-roughness has been also observed on the SEM micrographs. Based on a statistically approached experimental design, the effect of variant factors on droplet absorption time, static, advancing, receding contact angles and self-cleaning properties has been mathematically modeled according to the response surface methodology (RSM). PMID:22138117

  10. Methyl Radical in Clathrate Silica Voids. The Peculiar Physisorption Features of the Guest-Host Molecular Dynamics Interaction.

    PubMed

    Dmitriev, Yurij A; Buscarino, Gianpiero; Benetis, Nikolas P

    2016-08-11

    EPR line shape simulations of CH3/SiO2 clathrates and comparison to CH3/N2O and CH3/SiO2 experiments reveal the motional conditions of the CH3 radical up to the unusual regime of its stability, the high-temperature diffusional regime, at 300 K. In the low-temperature region, the CH3 in clathrates is found to rotate around the in-plane axes even at as low temperatures as 3.8 K. However, nonrotating methyls performing only libration about the C2-axes as well as around the C3-axis are also found, proving the existence of special sites in the clathrate voids that begin to accumulate a significant fraction of methyl radicals at temperatures below approximately 7 K. A distinctive feature in the spectrum anisotropy and line width temperature profiles is found nearby 25 K, which is interpreted as the radical physisorption inside the voids that occurs with the sample temperature lowering. The unusual increase of the CH3/SiO2 clathrate EPR spectral width with temperature over approximately 120 K has its origin in repeated angular momentum vector alterations due to frequent collisions with the clathrate void walls between periodical free rotation periods. This relaxation mechanism resembles to spin-rotation interaction known only for small molecular species in nonviscous fluids but unknown earlier for methyl hosted in solids. PMID:27405003

  11. Effects of temperature and salt concentration on the structural and dynamical features in aqueous solutions of charged triblock copolymers.

    PubMed

    Kjøniksen, Anna-Lena; Zhu, Kaizheng; Behrens, Manja A; Pedersen, Jan Skov; Nyström, Bo

    2011-03-17

    Effects of temperature and salt addition on the association behavior in aqueous solutions of a series of charged thermosensitive methoxypoly(ethylene glycol)-block-poly(N-isopropylacrylamide)-block-poly(4-styrenesulfonic acid sodium) triblock copolymers (MPEG(45)-b-P(NIPAAM)(n)-b-P(SSS)(22)) with different lengths of the PNIPAAM block (n=17, 48, and 66) have been studied with the aid of turbidity, small-angle X-ray scattering (SAXS), and dynamic light scattering (DLS). Increasing temperature and salinity as well as longer PNIPAAM blocks are all factors that promote the formation of association structures. The SAXS data show that, for the copolymers with n=48 and n=66, increasing temperature and salt concentration induce interchain associations and higher values of the aggregation number, whereas no aggregation was observed for the copolymer with the shortest PNIPAAM chain. However, DLS measurements reveal the presence of larger association clusters. The cloud point is found to decrease with raising salinity and longer PNIPAAM block. The general picture that emerges is the delicate interplay between repulsive electrostatic forces and hydrophobic interactions and that this balance can be tuned by changing the temperature, salinity, and the length of the PNIPAAM block. PMID:21338148

  12. Circular dichroism and site-directed spin labeling reveal structural and dynamical features of high-pressure states of myoglobin

    PubMed Central

    Lerch, Michael T.; Horwitz, Joseph; McCoy, John; Hubbell, Wayne L.

    2013-01-01

    Excited states of proteins may play important roles in function, yet are difficult to study spectroscopically because of their sparse population. High hydrostatic pressure increases the equilibrium population of excited states, enabling their characterization [Akasaka K (2003) Biochemistry 42:10875–85]. High-pressure site-directed spin-labeling EPR (SDSL-EPR) was developed recently to map the site-specific structure and dynamics of excited states populated by pressure. To monitor global secondary structure content by circular dichroism (CD) at high pressure, a modified optical cell using a custom MgF2 window with a reduced aperture is introduced. Here, a combination of SDSL-EPR and CD is used to map reversible structural transitions in holomyoglobin and apomyoglobin (apoMb) as a function of applied pressure up to 2 kbar. CD shows that the high-pressure excited state of apoMb at pH 6 has helical content identical to that of native apoMb, but reversible changes reflecting the appearance of a conformational ensemble are observed by SDSL-EPR, suggesting a helical topology that fluctuates slowly on the EPR time scale. Although the high-pressure state of apoMb at pH 6 has been referred to as a molten globule, the data presented here reveal significant differences from the well-characterized pH 4.1 molten globule of apoMb. Pressure-populated states of both holomyoglobin and apoMb at pH 4.1 have significantly less helical structure, and for the latter, that may correspond to a transient folding intermediate. PMID:24248390

  13. New features of vault architecture and dynamics revealed by novel refinement using the deformable elastic network approach.

    PubMed

    Casañas, Arnau; Querol-Audí, Jordi; Guerra, Pablo; Pous, Joan; Tanaka, Hideaki; Tsukihara, Tomitake; Verdaguer, Nuria; Fita, Ignasi

    2013-06-01

    The vault particle, with a molecular weight of about 10 MDa, is the largest ribonucleoprotein that has been described. The X-ray structure of intact rat vault has been solved at a resolution of 3.5 Å [Tanaka et al. (2009), Science, 323, 384-388], showing an overall barrel-shaped architecture organized into two identical moieties, each consisting of 39 copies of the major vault protein (MVP). The model deposited in the PDB includes 39 MVP copies (half a vault) in the crystal asymmetric unit. A 2.1 Å resolution structure of the seven N-terminal repeats (R1-7) of MVP has also been determined [Querol-Audí et al. (2009), EMBO J. 28, 3450-3457], revealing important discrepancies with respect to the MVP models for repeats R1 and R2. Here, the re-refinement of the vault structure by incorporating the high-resolution information available for the R1-7 domains, using the deformable elastic network (DEN) approach and maintaining strict 39-fold noncrystallographic symmetry is reported. The new refinement indicates that at the resolution presently available the MVP shell can be described well as only one independent subunit organized with perfect D39 molecular symmetry. This refinement reveals that significant rearrangements occur in the N-terminus of MVP during the closing of the two vault halves and that the 39-fold symmetry breaks in the cap region. These results reflect the highly dynamic nature of the vault structure and represent a necessary step towards a better understanding of the biology and regulation of this particle. PMID:23695250

  14. Circular dichroism and site-directed spin labeling reveal structural and dynamical features of high-pressure states of myoglobin.

    PubMed

    Lerch, Michael T; Horwitz, Joseph; McCoy, John; Hubbell, Wayne L

    2013-12-01

    Excited states of proteins may play important roles in function, yet are difficult to study spectroscopically because of their sparse population. High hydrostatic pressure increases the equilibrium population of excited states, enabling their characterization [Akasaka K (2003) Biochemistry 42:10875-85]. High-pressure site-directed spin-labeling EPR (SDSL-EPR) was developed recently to map the site-specific structure and dynamics of excited states populated by pressure. To monitor global secondary structure content by circular dichroism (CD) at high pressure, a modified optical cell using a custom MgF2 window with a reduced aperture is introduced. Here, a combination of SDSL-EPR and CD is used to map reversible structural transitions in holomyoglobin and apomyoglobin (apoMb) as a function of applied pressure up to 2 kbar. CD shows that the high-pressure excited state of apoMb at pH 6 has helical content identical to that of native apoMb, but reversible changes reflecting the appearance of a conformational ensemble are observed by SDSL-EPR, suggesting a helical topology that fluctuates slowly on the EPR time scale. Although the high-pressure state of apoMb at pH 6 has been referred to as a molten globule, the data presented here reveal significant differences from the well-characterized pH 4.1 molten globule of apoMb. Pressure-populated states of both holomyoglobin and apoMb at pH 4.1 have significantly less helical structure, and for the latter, that may correspond to a transient folding intermediate. PMID:24248390

  15. What Causes Sarcoidosis?

    MedlinePlus

    ... page from the NHLBI on Twitter. What Causes Sarcoidosis? The cause of sarcoidosis isn't known. More ... Content: NEXT >> Featured Video Living With and Managing Sarcoidosis 05/18/2011 This video—presented by the ...

  16. What Causes Atherosclerosis?

    MedlinePlus

    ... page from the NHLBI on Twitter. What Causes Atherosclerosis? The exact cause of atherosclerosis isn't known. ... Rate This Content: NEXT >> Featured Video What is atherosclerosis? 05/22/2014 Describes how the build-up ...

  17. Using Consumer Electronics and Apps in Industrial Environments - Development of a Framework for Dynamic Feature Deployment and Extension by Using Apps on Field Devices

    NASA Astrophysics Data System (ADS)

    Schmitt, Mathias

    2014-12-01

    The aim of this paper is to give a preliminary insight regarding the current work in the field of mobile interaction in industrial environments by using established interaction technologies and metaphors from the consumer goods industry. The major objective is the development and implementation of a holistic app-framework, which enables dynamic feature deployment and extension by using mobile apps on industrial field devices. As a result, field device functionalities can be updated and adapted effectively in accordance with well-known appconcepts from consumer electronics to comply with the urgent requirements of more flexible and changeable factory systems of the future. In addition, a much more user-friendly and utilizable interaction with field devices can be realized. Proprietary software solutions and device-stationary user interfaces can be overcome and replaced by uniform, cross-vendor solutions

  18. Constrained dynamics of localized excitations causes a non-equilibrium phase transition in an atomistic model of glass formers.

    PubMed

    Speck, Thomas; Chandler, David

    2012-05-14

    Recent progress has demonstrated that trajectory space for both kinetically constrained lattice models and atomistic models can be partitioned into a liquid-like and an inactive basin with a non-equilibrium phase transition separating these behaviors. Recent work has also established that excitations in atomistic models have statistics and dynamics like those in a specific class of kinetically constrained models. But it has not been known whether the non-equilibrium phase transitions occurring in the two classes of models have similar origins. Here, we show that the origin is indeed similar. In particular, we show that the number of excitations identified in an atomistic model serves as the order parameter for the inactive-active phase transition for that model. In this way, we show that the mechanism by which excitations are correlated in an atomistic model - by dynamical facilitation - is the mechanism from which the active-inactive phase transition emerges. We study properties of the inactive phase and show that it is amorphous lacking long-range order. We also discuss the choice of dynamical order parameters. PMID:22583302

  19. Prediction of ground motion and dynamic stress change in Baekdusan (Changbaishan) volcano caused by a North Korean nuclear explosion

    NASA Astrophysics Data System (ADS)

    Hong, Tae-Kyung; Choi, Eunseo; Park, Seongjun; Shin, Jin Soo

    2016-02-01

    Strong ground motions induce large dynamic stress changes that may disturb the magma chamber of a volcano, thus accelerating the volcanic activity. An underground nuclear explosion test near an active volcano constitutes a direct treat to the volcano. This study examined the dynamic stress changes of the magma chamber of Baekdusan (Changbaishan) that can be induced by hypothetical North Korean nuclear explosions. Seismic waveforms for hypothetical underground nuclear explosions at North Korean test site were calculated by using an empirical Green’s function approach based on a source-spectral model of a nuclear explosion; such a technique is efficient for regions containing poorly constrained velocity structures. The peak ground motions around the volcano were estimated from empirical strong-motion attenuation curves. A hypothetical M7.0 North Korean underground nuclear explosion may produce peak ground accelerations of 0.1684 m/s2 in the horizontal direction and 0.0917 m/s2 in the vertical direction around the volcano, inducing peak dynamic stress change of 67 kPa on the volcano surface and ~120 kPa in the spherical magma chamber. North Korean underground nuclear explosions with magnitudes of 5.0-7.6 may induce overpressure in the magma chamber of several tens to hundreds of kilopascals.

  20. Prediction of ground motion and dynamic stress change in Baekdusan (Changbaishan) volcano caused by a North Korean nuclear explosion.

    PubMed

    Hong, Tae-Kyung; Choi, Eunseo; Park, Seongjun; Shin, Jin Soo

    2016-01-01

    Strong ground motions induce large dynamic stress changes that may disturb the magma chamber of a volcano, thus accelerating the volcanic activity. An underground nuclear explosion test near an active volcano constitutes a direct treat to the volcano. This study examined the dynamic stress changes of the magma chamber of Baekdusan (Changbaishan) that can be induced by hypothetical North Korean nuclear explosions. Seismic waveforms for hypothetical underground nuclear explosions at North Korean test site were calculated by using an empirical Green's function approach based on a source-spectral model of a nuclear explosion; such a technique is efficient for regions containing poorly constrained velocity structures. The peak ground motions around the volcano were estimated from empirical strong-motion attenuation curves. A hypothetical M7.0 North Korean underground nuclear explosion may produce peak ground accelerations of 0.1684 m/s(2) in the horizontal direction and 0.0917 m/s(2) in the vertical direction around the volcano, inducing peak dynamic stress change of 67 kPa on the volcano surface and ~120 kPa in the spherical magma chamber. North Korean underground nuclear explosions with magnitudes of 5.0-7.6 may induce overpressure in the magma chamber of several tens to hundreds of kilopascals. PMID:26884136

  1. Prediction of ground motion and dynamic stress change in Baekdusan (Changbaishan) volcano caused by a North Korean nuclear explosion

    PubMed Central

    Hong, Tae-Kyung; Choi, Eunseo; Park, Seongjun; Shin, Jin Soo

    2016-01-01

    Strong ground motions induce large dynamic stress changes that may disturb the magma chamber of a volcano, thus accelerating the volcanic activity. An underground nuclear explosion test near an active volcano constitutes a direct treat to the volcano. This study examined the dynamic stress changes of the magma chamber of Baekdusan (Changbaishan) that can be induced by hypothetical North Korean nuclear explosions. Seismic waveforms for hypothetical underground nuclear explosions at North Korean test site were calculated by using an empirical Green’s function approach based on a source-spectral model of a nuclear explosion; such a technique is efficient for regions containing poorly constrained velocity structures. The peak ground motions around the volcano were estimated from empirical strong-motion attenuation curves. A hypothetical M7.0 North Korean underground nuclear explosion may produce peak ground accelerations of 0.1684 m/s2 in the horizontal direction and 0.0917 m/s2 in the vertical direction around the volcano, inducing peak dynamic stress change of 67 kPa on the volcano surface and ~120 kPa in the spherical magma chamber. North Korean underground nuclear explosions with magnitudes of 5.0–7.6 may induce overpressure in the magma chamber of several tens to hundreds of kilopascals. PMID:26884136

  2. Brine Flow Up a Borehole Caused by Pressure Perturbation From CO2 Storage: Static and Dynamic Evaluations

    EPA Science Inventory

    Industrial-scale storage of CO2 in saline sedimentary basins will cause zones of elevated pressure, larger than the CO2 plume itself. If permeable conduits (e.g., leaking wells) exist between the injection reservoir and overlying shallow aquifers, brine could be pushed upwards al...

  3. Shadow attenuation with high dynamic range images. Creating RGB images that allow feature classification in areas otherwise obscured by shadow or oversaturation.

    PubMed

    Cox, Samuel E; Booth, D Terrance

    2009-11-01

    Shadow often interferes with accurate image analysis. To mitigate shadow effects in near-earth imagery (2 m above ground level), we created high dynamic range (HDR) nadir images and used them to measure grassland ground cover. HDR composites were created by merging three differentially exposed images spanning a wide exposure range and resulted in lightened shadows. HDR images showed more detail; reduced the numbers of pure black, pure white, and pixels visually indistinguishable from black and white; reapportioned skewed luma values towards a normal distribution; and increased the Euclidean distance between litter and bare ground RGB values--allowing increased feature separation; all of which facilitated an increase in real feature classification through manual image analysis. Drawbacks to the method included decreased image sharpness due to minor misalignment of images or moving vegetation, time required to create HDR images, and difficulty with acquiring primary images from a moving platform. We conclude that HDR imagery can provide more accurate measurements of bare soil cover for ecosystem monitoring and assessment. PMID:18972218

  4. Subpicosecond Exciton Dynamics and Biexcitonic Feature in Colloidal CuInS2 Nanocrystals: Role of In-Cu Antisite Defects.

    PubMed

    Debnath, Tushar; Maiti, Sourav; Maity, Partha; Ghosh, Hirendra N

    2015-09-01

    Charge carrier dynamics of multinary quantum dots like CuInS2 (CIS) nanocrystals (NCs) is not clearly understood, especially in ultrafast time scales. Herein we have synthesized colloidal CIS NCs that show defect-induced emission between donor (antisite) and acceptor (internal/surface) states as indicated from steady-state and time-resolved photoluminescence (PL) measurements. Subpicosecond transient absorption (TA) spectra of CIS NCs reveal a gradient of electronic states that exists above the conduction band edge. The electron cooling rate has been determined to be ∼0.1-0.15 eV/ps. The cascade of electron cooling dynamics was monitored after following the TA kinetics at different electronic states. Interestingly, the kinetics at the antisite state unveil a biexcitonic feature, which has been enlightened through a probe-induced biexciton mechanism. With progressively higher fluence (⟨N⟩), the biexciton binding energy increases, and the electron cooling to the antisite state considerably slows down. Extra energy released during Auger recombination of bi/multiexcitons are used to re-excite the electron to a further high energy level, resulting in longer electron cooling time to the antisite states. PMID:26273721

  5. Pattern evolution caused by dynamic coupling between wetting and phase separation in binary liquid mixture containing glass particles

    NASA Astrophysics Data System (ADS)

    Tanaka, Hajime; Lovinger, Andew J.; Davis, Don D.

    1994-04-01

    We demonstrate here that the pattern evolution in a binary liquid mixture containing glass spheres is strongly affected by the dynamic coupling between phase separation and wetting. Because of the difference in the wettability to glass between the two phases, the glass particles are preferentially included in the more wettable phase. The resulting pattern is strongly dependent on whether the spheres are mobile or immobile. For a high density of mobile particles, we find that an initially random pattern of spheres transforms into an ordered pattern because of geometrical confinement of particles into the more wettable phase.

  6. Computational model for calculating the dynamical behaviour of generators caused by unbalanced magnetic pull and experimental validation

    NASA Astrophysics Data System (ADS)

    Pennacchi, Paolo

    2008-04-01

    The modelling of the unbalanced magnetic pull (UMP) in generators and the experimental validation of the proposed method are presented in this paper. The UMP is one of the most remarkable effects of electromechanical interactions in rotating machinery. As a consequence of the rotor eccentricity, the imbalance of the electromagnetic forces acting between rotor and stator generates a net radial force. This phenomenon can be avoided by means of a careful assembly and manufacture in small and stiff machines, like electrical motors. On the contrary, the eccentricity of the active part of the rotor with respect to the stator is unavoidable in big generators of power plants, because they operate above their first critical speed and are supported by oil-film bearings. In the first part of the paper, a method aimed to calculate the UMP force is described. This model is more general than those available in literature, which are limited to circular orbits. The model is based on the actual position of the rotor inside the stator, therefore on the actual air-gap distribution, regardless of the orbit type. The closed form of the nonlinear UMP force components is presented. In the second part, the experimental validation of the proposed model is presented. The dynamical behaviour in the time domain of a steam turbo-generator of a power plant is considered and it is shown that the model is able to reproduce the dynamical effects due to the excitation of the magnetic field in the generator.

  7. Maternal diabetes causes abnormal dynamic changes of endoplasmic reticulum during mouse oocyte maturation and early embryo development

    PubMed Central

    2013-01-01

    Background The adverse effects of maternal diabetes on oocyte maturation and embryo development have been reported. Methods In this study, we used time-lapse live cell imaging confocal microscopy to investigate the dynamic changes of ER and the effects of diabetes on the ER’s structural dynamics during oocyte maturation, fertilization and early embryo development. Results We report that the ER first became remodeled into a dense ring around the developing MI spindle, and then surrounded the spindle during migration to the cortex. ER reorganization during mouse early embryo development was characterized by striking localization around the pronuclei in the equatorial section, in addition to larger areas of fluorescence deeper within the cytoplasm. In contrast, in diabetic mice, the ER displayed a significantly higher percentage of homogeneous distribution patterns throughout the entire ooplasm during oocyte maturation and early embryo development. In addition, a higher frequency of large ER aggregations was detected in GV oocytes and two cell embryos from diabetic mice. Conclusions These results suggest that the diabetic condition adversely affects the ER distribution pattern during mouse oocyte maturation and early embryo development. PMID:23597066

  8. Wolf population dynamics in the U.S. Northern Rocky Mountains are affected by recruitment and human-caused mortality

    USGS Publications Warehouse

    Gude, J.A.; Mitchell, M.S.; Russell, R.E.; Sime, C.A.; Bangs, E.E.; Mech, L.D.; Ream, R.R.

    2012-01-01

    Reliable analyses can help wildlife managers make good decisions, which are particularly critical for controversial decisions such as wolf (Canis lupus) harvest. Creel and Rotella (2010) recently predicted substantial population declines in Montana wolf populations due to harvest, in contrast to predictions made by Montana Fish, Wildlife and Parks (MFWP). We replicated their analyses considering only those years in which field monitoring was consistent, and we considered the effect of annual variation in recruitment on wolf population growth. Rather than assuming constant rates, we used model selection methods to evaluate and incorporate models of factors driving recruitment and human-caused mortality rates in wolf populations in the Northern Rocky Mountains. Using data from 27 area-years of intensive wolf monitoring, we show that variation in both recruitment and human-caused mortality affect annual wolf population growth rates and that human-caused mortality rates have increased with the sizes of wolf populations. We document that recruitment rates have decreased over time, and we speculate that rates have decreased with increasing population sizes and/or that the ability of current field resources to document recruitment rates has recently become less successful as the number of wolves in the region has increased. Estimates of positive wolf population growth in Montana from our top models are consistent with field observations and estimates previously made by MFWP for 2008-2010, whereas the predictions for declining wolf populations of Creel and Rotella (2010) are not. Familiarity with limitations of raw data, obtained first-hand or through consultation with scientists who collected the data, helps generate more reliable inferences and conclusions in analyses of publicly available datasets. Additionally, development of efficient monitoring methods for wolves is a pressing need, so that analyses such as ours will be possible in future years when fewer resources

  9. Unusual Pulmonary Arterial Filling Defect caused by Systemic to Pulmonary Shunt in the Setting of Chronic Lung Disease Demonstrated by Dynamic 4D CTA

    PubMed Central

    Ansari-Gilani, Kianoush; Gilkeson, Robert C; Hsiao, Edward M; Rajiah, Prabhakar

    2015-01-01

    Even though pulmonary embolism is by far the most common cause of filling defect in the pulmonary arterial system, other less common etiologies should be considered especially in the setting of atypical clinical scenario or unusual imaging findings. Unusual pattern of filling defect in the pulmonary artery in the setting of chronic inflammatory/fibrotic parenchymal lung disease should raise the concern for systemic to pulmonary artery shunt. This diagnosis is typically made by conventional angiography. Dynamic 4D CT angiography however can be a safe, noninvasive and effective alternative tool for making such a diagnosis. It has the added value of multiplanar reconstruction capabilities and providing detailed anatomy which can be vital for interventional radiologists when planning their approach for possible intervention. We present 2 cases of such shunts, and illustrate the demonstration of these shunts by using dynamic 4D CT angiography. PMID:27252791

  10. Dynamical Regulation Analysis Identifies Molecular Mechanisms of Fuzheng-Huayu Formula against Hepatitis B-Caused Liver Cirrhosis

    PubMed Central

    Chen, Qi-Long; Lu, Yi-Yu; Peng, Jing-Hua; Dong, Shu; Wei, Bin; Song, Ya-Nan; Zhou, Qian-Mei; Zhang, Hui; Liu, Ping; Su, Shi-Bing

    2015-01-01

    Fuzheng-Huayu (FZHY) tablet was formulated based on Chinese medicine theory in treating liver fibrosis. A clinical trial has indicated that FZHY can against hepatitis B-caused liver cirrhosis (HBC), but the underlying mechanism of FZHY efficacy is unclear. Here, we report that miRNA expression levels are remarkably changed when FZHY formula was used in HBC patient's treatment as a paradigm of trials. Then, we functionally characterize the significant impact of potential kernel miRNAs by miRNA-target network analysis. Enrichment analysis show that the FZHY formula dramatically effecting the molecular regulated module in HBC. Thus, we infer that FZHY plays a critical function in HBC treatment process and directly regulated many important pathways, including but not limited to cell cycle, p53 signaling pathway, and TGF-β signaling pathway, suggesting a new strategy for investigating the molecular mechanism of FZHY treatment. PMID:26221171

  11. Phase matching of high order harmonic generation using dynamic phase modulation caused by a non-collinear modulation pulse

    DOEpatents

    Cohen, Oren; Kapteyn, Henry C.; Mumane, Margaret M.

    2010-02-16

    Phase matching high harmonic generation (HHG) uses a single, long duration non-collinear modulating pulse intersecting the driving pulse. A femtosecond driving pulse is focused into an HHG medium (such as a noble gas) to cause high-harmonic generation (HHG), for example in the X-ray region of the spectrum, via electrons separating from and recombining with gas atoms. A non-collinear pulse intersects the driving pulse within the gas, and modulates the field seen by the electrons while separated from their atoms. The modulating pulse is low power and long duration, and its frequency and amplitude is chosen to improve HHG phase matching by increasing the areas of constructive interference between the driving pulse and the HHG, relative to the areas of destructive interference.

  12. Understanding the Dynamic and Thermodynamic Causes of Historical Trends in the Intraseasonal Variability of the South Asian Summer Monsoon

    NASA Astrophysics Data System (ADS)

    Singh, D.; Horton, D. E.; Diffenbaugh, N. S.

    2014-12-01

    The Indian Summer Monsoon directly affects the lives of over 1/6th of the world's population, being critical for agriculture (>50% of the agricultural lands are still rainfed) and water availability in the subcontinent. The summer monsoon is characterized by a dominant 30-60 day mode of intraseasonal variability causing the occurrence of wet and dry spells over a substantial portion of India during the peak-monsoon months (July-August). We use a 1°x1° gridded rainfall dataset (1951-2011) from the Indian Meteorological Department to quantify changes in the mean and intraseasonal variability of daily summer monsoon rainfall across India. Using a non-parametric statistical methodology to account for temporal correlation in the time-series, we find a statistically significant decreasing trend in rainfall and increasing trend in variability in many regions, and changes in the characteristics of wet and dry spells.Using geopotential heights from the NCEP reanalysis dataset, we apply the Self-Organizing Maps (SOMs) approach (cluster analysis) to define typical upper (200mb) and lower-level (850mb) atmospheric patterns associated with extreme wet and dry conditions in the different sub-regions within India. We identify the extreme wet and dry spell patterns from the precipitation composites associated with the SOM patterns. Next, we link the contribution of the changing frequency of occurrence of the associated atmospheric patterns and increasing moisture availability in response to atmospheric warming to observed trends in these extremes. Lastly, we compare the changes in the frequency of occurrence of these atmospheric patterns in the historical and pre-industrial simulations from a single GCM to examine the influence of global warming on these extremes. Understanding the causes of these observed changes in wet and dry extremes during the monsoon season and responses to increasing global warming are relevant for managing climate-related risks, with particular relevance

  13. Energetic changes caused by antigenic module insertion in a virus-like particle revealed by experiment and molecular dynamics simulations.

    PubMed

    Zhang, Lin; Tang, Ronghong; Bai, Shu; Connors, Natalie K; Lua, Linda H L; Chuan, Yap P; Middelberg, Anton P J; Sun, Yan

    2014-01-01

    The success of recombinant virus-like particles (VLPs) for human papillomavirus and hepatitis B demonstrates the potential of VLPs as safe and efficacious vaccines. With new modular designs emerging, the effects of antigen module insertion on the self-assembly and structural integrity of VLPs should be clarified so as to better enabling improved design. Previous work has revealed insights into the molecular energetics of a VLP subunit, capsomere, comparing energetics within various solution conditions known to drive or inhibit self-assembly. In the present study, molecular dynamics (MD) simulations coupled with the molecular mechanics-Poisson-Boltzmann surface area (MM-PBSA) method were performed to examine the molecular interactions and energetics in a modular capsomere of a murine polyomavirus (MPV) VLP designed to protect against influenza. Insertion of an influenza antigenic module is found to lower the binding energy within the capsomere, and a more active state is observed in Assembly Buffer as compared with that in Stabilization Buffer, which has been experimentally validated through measurements using differential scanning calorimetry. Further in-depth analysis based on free-energy decomposition indicates that destabilized binding can be attributed to electrostatic interaction induced by the chosen antigen module. These results provide molecular insights into the conformational stability of capsomeres and their abilities to be exploited for antigen presentation, and are expected to be beneficial for the biomolecular engineering of VLP vaccines. PMID:25215874

  14. Viral Transmission Dynamics at Single-Cell Resolution Reveal Transiently Immune Subpopulations Caused by a Carrier State Association

    PubMed Central

    Cenens, William; Makumi, Angela; Govers, Sander K.; Lavigne, Rob; Aertsen, Abram

    2015-01-01

    Monitoring the complex transmission dynamics of a bacterial virus (temperate phage P22) throughout a population of its host (Salmonella Typhimurium) at single cell resolution revealed the unexpected existence of a transiently immune subpopulation of host cells that emerged from peculiarities preceding the process of lysogenization. More specifically, an infection event ultimately leading to a lysogen first yielded a phage carrier cell harboring a polarly tethered P22 episome. Upon subsequent division, the daughter cell inheriting this episome became lysogenized by an integration event yielding a prophage, while the other daughter cell became P22-free. However, since the phage carrier cell was shown to overproduce immunity factors that are cytoplasmically inherited by the P22-free daughter cell and further passed down to its siblings, a transiently resistant subpopulation was generated that upon dilution of these immunity factors again became susceptible to P22 infection. The iterative emergence and infection of transiently resistant subpopulations suggests a new bet-hedging strategy by which viruses could manage to sustain both vertical and horizontal transmission routes throughout an infected population without compromising a stable co-existence with their host. PMID:26720743

  15. The raft of the Saint-Jean River, Gaspé (Québec, Canada): A dynamic feature trapping most of the wood transported from the catchment

    NASA Astrophysics Data System (ADS)

    Boivin, Maxime; Buffin-Bélanger, Thomas; Piégay, Hervé

    2015-02-01

    The rivers of the Gaspé Peninsula, Québec (Canada), a coastal drainage system of the St. Lawrence River, receive and transport vast quantities of large wood. The rapid rate of channel shifting caused by high-energy flows and noncohesive banks allows wood recruitment that in turn greatly influences river dynamics. The delta of the Saint-Jean River has accumulated wood since 1960, leading to frequent avulsions over that time period. The wood raft there is now more than 3-km in length, which is unusual but natural. This jam configuration allows a unique opportunity to estimate a wood budget at the scale of a long river corridor and to better understand the dynamics of large wood (LW) in rivers. A wood budget includes the evaluation of wood volumes (i) produced by bank erosion (input), (ii) still in transit in the river corridor (deposited on sand bars or channel edges), and (iii) accumulated in the delta (output). The budget is based on an analysis of aerial photos dating back to 1963 as well as surveys carried out in 2010, all of which were used to locate and describe large wood accumulations along a 60-km river section. The main results of this paper show that the raft formation in the delta is dynamic and can be massive, but it is a natural process. Considering the estimated wood volume trapped in the delta from 1963 to 2013 (≈ 25,000 m3), two important points are revealed by the quantification of the wood recruitment volume from 1963 to 2004 (≈ 27,000 m3 ± 400 m3) and of the wood volume stored on the bars in 2010 (≈ 5950 m3). First, the recruitment of large wood from lateral migration for the 40-year period can account for the volume of large wood in the delta and in transit. Second, the excess wood volume produced by lateral migration and avulsion represents a minimum estimation of the large wood trapped on the floodplain owing to wood volume that has decomposed and large wood that exited the river system. Rafts are major trapping structures that provide

  16. A Forward Dynamic Modelling Investigation of Cause-and-Effect Relationships in Single Support Phase of Human Walking.

    PubMed

    McGrath, Michael; Howard, David; Baker, Richard

    2015-01-01

    Mathematical gait models often fall into one of two categories: simple and complex. There is a large leap in complexity between model types, meaning the effects of individual gait mechanisms get overlooked. This study investigated the cause-and-effect relationships between gait mechanisms and resulting kinematics and kinetics, using a sequence of mathematical models of increasing complexity. The focus was on sagittal plane and single support only. Starting with an inverted pendulum (IP), extended to include a HAT (head-arms-trunk) segment and an actuated hip moment, further complexities were added one-by-one. These were a knee joint, an ankle joint with a static foot, heel rise, and finally a swing leg. The presence of a knee joint and an ankle moment (during foot flat) were shown to largely influence the initial peak in the vertical GRF curve. The second peak in this curve was achieved through a combination of heel rise and the presence of a swing leg. Heel rise was also shown to reduce errors in the horizontal GRF prediction in the second half of single support. The swing leg is important for centre-of-mass (CM) deceleration in late single support. These findings provide evidence for the specific effects of each gait mechanism. PMID:26175797

  17. A Forward Dynamic Modelling Investigation of Cause-and-Effect Relationships in Single Support Phase of Human Walking

    PubMed Central

    McGrath, Michael; Howard, David; Baker, Richard

    2015-01-01

    Mathematical gait models often fall into one of two categories: simple and complex. There is a large leap in complexity between model types, meaning the effects of individual gait mechanisms get overlooked. This study investigated the cause-and-effect relationships between gait mechanisms and resulting kinematics and kinetics, using a sequence of mathematical models of increasing complexity. The focus was on sagittal plane and single support only. Starting with an inverted pendulum (IP), extended to include a HAT (head-arms-trunk) segment and an actuated hip moment, further complexities were added one-by-one. These were a knee joint, an ankle joint with a static foot, heel rise, and finally a swing leg. The presence of a knee joint and an ankle moment (during foot flat) were shown to largely influence the initial peak in the vertical GRF curve. The second peak in this curve was achieved through a combination of heel rise and the presence of a swing leg. Heel rise was also shown to reduce errors in the horizontal GRF prediction in the second half of single support. The swing leg is important for centre-of-mass (CM) deceleration in late single support. These findings provide evidence for the specific effects of each gait mechanism. PMID:26175797

  18. Tissue loss (white syndrome) in the coral Montipora capitata is a dynamic disease with multiple host responses and potential causes.

    PubMed

    Work, Thierry M; Russell, Robin; Aeby, Greta S

    2012-11-01

    Tissue loss diseases or white syndromes (WS) are some of the most important coral diseases because they result in significant colony mortality and morbidity, threatening dominant Acroporidae in the Caribbean and Pacific. The causes of WS remain elusive in part because few have examined affected corals at the cellular level. We studied the cellular changes associated with WS over time in a dominant Hawaiian coral, Montipora capitata, and showed that: (i) WS has rapidly progressing (acute) phases mainly associated with ciliates or slowly progressing (chronic) phases mainly associated with helminths or chimeric parasites; (ii) these phases interchanged and waxed and waned; (iii) WS could be a systemic disease associated with chimeric parasitism or a localized disease associated with helminths or ciliates; (iv) corals responded to ciliates mainly with necrosis and to helminths or chimeric parasites with wound repair; (v) mixed infections were uncommon; and (vi) other than cyanobacteria, prokaryotes associated with cell death were not seen. Recognizing potential agents associated with disease at the cellular level and the host response to those agents offers a logical deductive rationale to further explore the role of such agents in the pathogenesis of WS in M. capitata and helps explain manifestation of gross lesions. This approach has broad applicability to the study of the pathogenesis of coral diseases in the field and under experimental settings. PMID:22951746

  19. Tissue loss (white syndrome) in the coral Montipora capitata is a dynamic disease with multiple host responses and potential causes

    USGS Publications Warehouse

    Work, Thierry M.; Russell, Robin; Aeby, Greta S.

    2012-01-01

    Tissue loss diseases or white syndromes (WS) are some of the most important coral diseases because they result in significant colony mortality and morbidity, threatening dominant Acroporidae in the Caribbean and Pacific. The causes of WS remain elusive in part because few have examined affected corals at the cellular level. We studied the cellular changes associated with WS over time in a dominant Hawaiian coral, Montipora capitata, and showed that: (i) WS has rapidly progressing (acute) phases mainly associated with ciliates or slowly progressing (chronic) phases mainly associated with helminths or chimeric parasites; (ii) these phases interchanged and waxed and waned; (iii) WS could be a systemic disease associated with chimeric parasitism or a localized disease associated with helminths or ciliates; (iv) corals responded to ciliates mainly with necrosis and to helminths or chimeric parasites with wound repair; (v) mixed infections were uncommon; and (vi) other than cyanobacteria, prokaryotes associated with cell death were not seen. Recognizing potential agents associated with disease at the cellular level and the host response to those agents offers a logical deductive rationale to further explore the role of such agents in the pathogenesis of WS in M. capitata and helps explain manifestation of gross lesions. This approach has broad applicability to the study of the pathogenesis of coral diseases in the field and under experimental settings.

  20. Vascular disease-causing mutation R258C in ACTA2 disrupts actin dynamics and interaction with myosin

    PubMed Central

    Lu, Hailong; Fagnant, Patricia M.; Bookwalter, Carol S.; Joel, Peteranne; Trybus, Kathleen M.

    2015-01-01

    Point mutations in vascular smooth muscle α-actin (SM α-actin), encoded by the gene ACTA2, are the most prevalent cause of familial thoracic aortic aneurysms and dissections (TAAD). Here, we provide the first molecular characterization, to our knowledge, of the effect of the R258C mutation in SM α-actin, expressed with the baculovirus system. Smooth muscles are unique in that force generation requires both interaction of stable actin filaments with myosin and polymerization of actin in the subcortical region. Both aspects of R258C function therefore need investigation. Total internal reflection fluorescence (TIRF) microscopy was used to quantify the growth of single actin filaments as a function of time. R258C filaments are less stable than WT and more susceptible to severing by cofilin. Smooth muscle tropomyosin offers little protection from cofilin cleavage, unlike its effect on WT actin. Unexpectedly, profilin binds tighter to the R258C monomer, which will increase the pool of globular actin (G-actin). In an in vitro motility assay, smooth muscle myosin moves R258C filaments more slowly than WT, and the slowing is exacerbated by smooth muscle tropomyosin. Under loaded conditions, small ensembles of myosin are unable to produce force on R258C actin-tropomyosin filaments, suggesting that tropomyosin occupies an inhibitory position on actin. Many of the observed defects cannot be explained by a direct interaction with the mutated residue, and thus the mutation allosterically affects multiple regions of the monomer. Our results align with the hypothesis that defective contractile function contributes to the pathogenesis of TAAD. PMID:26153420

  1. Sediment-phosphorus dynamics can shift aquatic ecology and cause downstream legacy effects after wildfire in large river systems.

    PubMed

    Emelko, Monica B; Stone, Micheal; Silins, Uldis; Allin, Don; Collins, Adrian L; Williams, Chris H S; Martens, Amanda M; Bladon, Kevin D

    2016-03-01

    Global increases in the occurrence of large, severe wildfires in forested watersheds threaten drinking water supplies and aquatic ecology. Wildfire effects on water quality, particularly nutrient levels and forms, can be significant. The longevity and downstream propagation of these effects as well as the geochemical mechanisms regulating them remain largely undocumented at larger river basin scales. Here, phosphorus (P) speciation and sorption behavior of suspended sediment were examined in two river basins impacted by a severe wildfire in southern Alberta, Canada. Fine-grained suspended sediments (<125 μm) were sampled continuously during ice-free conditions over a two-year period (2009-2010), 6 and 7 years after the wildfire. Suspended sediment samples were collected from upstream reference (unburned) river reaches, multiple tributaries within the burned areas, and from reaches downstream of the burned areas, in the Crowsnest and Castle River basins. Total particulate phosphorus (TPP) and particulate phosphorus forms (nonapatite inorganic P, apatite P, organic P), and the equilibrium phosphorus concentration (EPC0 ) of suspended sediment were assessed. Concentrations of TPP and the EPC0 were significantly higher downstream of wildfire-impacted areas compared to reference (unburned) upstream river reaches. Sediments from the burned tributary inputs contained higher levels of bioavailable particulate P (NAIP) - these effects were also observed downstream at larger river basin scales. The release of bioavailable P from postfire, P-enriched fine sediment is a key mechanism causing these effects in gravel-bed rivers at larger basin scales. Wildfire-associated increases in NAIP and the EPC0 persisted 6 and 7 years after wildfire. Accordingly, this work demonstrated that fine sediment in gravel-bed rivers is a significant, long-term source of in-stream bioavailable P that contributes to a legacy of wildfire impacts on downstream water quality, aquatic ecology, and

  2. Vascular disease-causing mutation R258C in ACTA2 disrupts actin dynamics and interaction with myosin.

    PubMed

    Lu, Hailong; Fagnant, Patricia M; Bookwalter, Carol S; Joel, Peteranne; Trybus, Kathleen M

    2015-08-01

    Point mutations in vascular smooth muscle α-actin (SM α-actin), encoded by the gene ACTA2, are the most prevalent cause of familial thoracic aortic aneurysms and dissections (TAAD). Here, we provide the first molecular characterization, to our knowledge, of the effect of the R258C mutation in SM α-actin, expressed with the baculovirus system. Smooth muscles are unique in that force generation requires both interaction of stable actin filaments with myosin and polymerization of actin in the subcortical region. Both aspects of R258C function therefore need investigation. Total internal reflection fluorescence (TIRF) microscopy was used to quantify the growth of single actin filaments as a function of time. R258C filaments are less stable than WT and more susceptible to severing by cofilin. Smooth muscle tropomyosin offers little protection from cofilin cleavage, unlike its effect on WT actin. Unexpectedly, profilin binds tighter to the R258C monomer, which will increase the pool of globular actin (G-actin). In an in vitro motility assay, smooth muscle myosin moves R258C filaments more slowly than WT, and the slowing is exacerbated by smooth muscle tropomyosin. Under loaded conditions, small ensembles of myosin are unable to produce force on R258C actin-tropomyosin filaments, suggesting that tropomyosin occupies an inhibitory position on actin. Many of the observed defects cannot be explained by a direct interaction with the mutated residue, and thus the mutation allosterically affects multiple regions of the monomer. Our results align with the hypothesis that defective contractile function contributes to the pathogenesis of TAAD. PMID:26153420

  3. Effects of disturbances caused by coastal constructions on spatial structure, growth dynamics and photosynthesis of the seagrass Posidonia oceanica.

    PubMed

    Ruiz, J M; Romero, J

    2003-12-01

    The light-limitation hypothesis was tested to assess whether water turbidity had caused the decline of a Mediterranean Posidonia oceanica (L.) Delile meadow in an area affected by a harbor. The annual growth, photosynthesis and rhizome starch concentrations of seagrass were measured and related to changes in light availability and dissolved nutrient concentration along a gradient of meadow degradation from areas close to the harbor outwards. Environmental and plant variables were measured in three stations placed along this gradient and compared with a reference station at an undisturbed meadow. The light attenuation coefficient (k) increased toward the inner harbor area, mainly due to sediment resuspension. The shoot density and leaf productivity of P. oceanica shoots were much lower in disturbed stations of the inner harbor area than in the outer, less disturbed station and the reference meadow. However, daily leaf carbon gains, calculated from the photosynthetic rates at saturating irradiance (P(max)) and the daily period in which seagrass receives light higher than its saturating irradiance (H(sat)), suggested positive C-balance in all stations. This was partly explained by photo-acclimatization of seagrass to the reduced light availability at the disturbed harbor stations (inner and intermediate), as indicated by the lengthening of H(sat) and the decrease in saturating irradiance (I(sat)) and respiratory demands. Despite photo-acclimatization, disturbed harbor stations showed less positive C-balance, seen not only in their lower leaf growth and biomass but also in a decrease in rhizome carbohydrate reserves (starch). Our results suggest that light reduction account for the reduced seagrass productivity and abundance. However, meadow decline (in terms of shoot mortality) in the harbor area is well above that predicted from similar light environments of nearby meadows or simulated in shading experiments. Thus, there are other factors than light limitation

  4. Genome-wide analysis of tandem repeats in Tribolium castaneum genome reveals abundant and highly dynamic tandem repeat families with satellite DNA features in euchromatic chromosomal arms

    PubMed Central

    Pavlek, Martina; Gelfand, Yevgeniy; Plohl, Miroslav; Meštrović, Nevenka

    2015-01-01

    Although satellite DNAs are well-explored components of heterochromatin and centromeres, little is known about emergence, dispersal and possible impact of comparably structured tandem repeats (TRs) on the genome-wide scale. Our bioinformatics analysis of assembled Tribolium castaneum genome disclosed significant contribution of TRs in euchromatic chromosomal arms and clear predominance of satellite DNA-typical 170 bp monomers in arrays of ≥5 repeats. By applying different experimental approaches, we revealed that the nine most prominent TR families Cast1–Cast9 extracted from the assembly comprise ∼4.3% of the entire genome and reside almost exclusively in euchromatic regions. Among them, seven families that build ∼3.9% of the genome are based on ∼170 and ∼340 bp long monomers. Results of phylogenetic analyses of 2500 monomers originating from these families show high-sequence dynamics, evident by extensive exchanges between arrays on non-homologous chromosomes. In addition, our analysis shows that concerted evolution acts more efficiently on longer than on shorter arrays. Efficient genome-wide distribution of nine TR families implies the role of transposition only in expansion of the most dispersed family, and involvement of other mechanisms is anticipated. Despite similarities in sequence features, FISH experiments indicate high-level compartmentalization of centromeric and euchromatic tandem repeats. PMID:26428853

  5. Cellular Composition of the Spleen and Changes in Splenic Lysosomes in the Dynamics of Dyslipidemia in Mice Caused by Repeated Administration of Poloxamer 407.

    PubMed

    Goncharova, N V; Shurlygina, A V; Mel'nikova, E V; Karmatskikh, O L; Avrorov, P A; Loktev, K V; Korolenko, T A

    2015-11-01

    We studied the effect of dyslipidemia induced by poloxamer 407 (300 mg/kg twice a week for 30 days) on cellular composition of the spleen and splenocyte lysosomes in mice. Changes in blood lipid profile included elevated concentrations of total cholesterol, aterogenic LDL, and triglycerides most pronounced in 24 h after the last poloxamer 407 injection; gradual normalization of lipid profile was observed in 4 days (except triglycerides) and 10 days. The most pronounced changes in the spleen (increase in organ weight and number of cells, inhibition in apoptosis, and reduced accumulation of vital dye acridine orange in lysosomes) were detected on day 4; on day 10, the indices returned to normal. Cathepsin D activity in the spleen also increased at these terms. The relationship between changes in the cellular composition of the spleen and dynamics of serum lipid profile in mice in dyslipidemia caused by repeated administrations of relatively low doses of poloxamer 407 is discussed. PMID:26608379

  6. In-silico analysis of binding site features and substrate selectivity in plant flavonoid-3-O glycosyltransferases (F3GT) through molecular modeling, docking and dynamics simulation studies.

    PubMed

    Sharma, Ranu; Panigrahi, Priyabrata; Suresh, C G

    2014-01-01

    Flavonoids are a class of plant secondary metabolites that act as storage molecules, chemical messengers, as well as participate in homeostasis and defense processes. They possess pharmaceutical properties important for cancer treatment such as antioxidant and anti-tumor activities. The drug-related properties of flavonoids can be improved by glycosylation. The enzymes glycosyltransferases (GTs) glycosylate acceptor molecules in a regiospecific manner with the help of nucleotide sugar donor molecules. Several plant GTs have been characterized and their amino acid sequences determined. However, three-dimensional structures of only a few are reported. Here, phylogenetic analysis using amino acid sequences have identified a group of GTs with the same regiospecific activity. The structures of these closely related GTs were modeled using homologous GT structures. Their substrate binding sites were elaborated by docking flavonoid acceptor and UDP-sugar donor molecules in the modeled structures. Eight regions near the acceptor binding site in the N- and C- terminal domain of GTs have been identified that bind and specifically glycosylate the 3-OH group of acceptor flavonoids. Similarly, a conserved motif in the C-terminal domain is known to bind a sugar donor substrate. In certain GTs, the substitution of a specific glutamine by histidine in this domain changes the preference of sugar from glucose to galactose as a result of changed pattern of interactions. The molecular modeling, docking, and molecular dynamics simulation studies have revealed the chemical and topological features of the binding site and thus provided insights into the basis of acceptor and donor recognition by GTs. PMID:24667893

  7. In-Silico Analysis of Binding Site Features and Substrate Selectivity in Plant Flavonoid-3-O Glycosyltransferases (F3GT) through Molecular Modeling, Docking and Dynamics Simulation Studies

    PubMed Central

    Sharma, Ranu; Panigrahi, Priyabrata; Suresh, C.G.

    2014-01-01

    Flavonoids are a class of plant secondary metabolites that act as storage molecules, chemical messengers, as well as participate in homeostasis and defense processes. They possess pharmaceutical properties important for cancer treatment such as antioxidant and anti-tumor activities. The drug-related properties of flavonoids can be improved by glycosylation. The enzymes glycosyltransferases (GTs) glycosylate acceptor molecules in a regiospecific manner with the help of nucleotide sugar donor molecules. Several plant GTs have been characterized and their amino acid sequences determined. However, three-dimensional structures of only a few are reported. Here, phylogenetic analysis using amino acid sequences have identified a group of GTs with the same regiospecific activity. The structures of these closely related GTs were modeled using homologous GT structures. Their substrate binding sites were elaborated by docking flavonoid acceptor and UDP-sugar donor molecules in the modeled structures. Eight regions near the acceptor binding site in the N- and C- terminal domain of GTs have been identified that bind and specifically glycosylate the 3-OH group of acceptor flavonoids. Similarly, a conserved motif in the C-terminal domain is known to bind a sugar donor substrate. In certain GTs, the substitution of a specific glutamine by histidine in this domain changes the preference of sugar from glucose to galactose as a result of changed pattern of interactions. The molecular modeling, docking, and molecular dynamics simulation studies have revealed the chemical and topological features of the binding site and thus provided insights into the basis of acceptor and donor recognition by GTs. PMID:24667893

  8. Leading Causes of Blindness

    MedlinePlus

    ... of this page please turn Javascript on. Feature: Vision Leading Causes of Blindness Past Issues / Winter 2012 ... of the lenses in your eyes. They affect vision and are very common in older people. More ...

  9. Leading Causes of Blindness

    MedlinePlus

    ... Navigation Bar Home Current Issue Past Issues Feature: Vision Leading Causes of Blindness Past Issues / Summer 2008 ... of the lenses in your eyes. They affect vision and are very common in older people. More ...

  10. Identification of possible siRNA molecules for TDP43 mutants causing amyotrophic lateral sclerosis: In silico design and molecular dynamics study.

    PubMed

    Bhandare, Vishwambhar Vishnu; Ramaswamy, Amutha

    2016-04-01

    The DNA binding protein, TDP43 is a major protein involved in amyotrophic lateral sclerosis and other neurological disorders such as frontotemporal dementia, Alzheimer disease, etc. In the present study, we have designed possible siRNAs for the glycine rich region of tardbp mutants causing ALS disorder based on a systematic theoretical approach including (i) identification of respective codons for all mutants (reported at the protein level) based on both minimum free energy and probabilistic approaches, (ii) rational design of siRNA, (iii) secondary structure analysis for the target accessibility of siRNA, (iii) determination of the ability of siRNA to interact with mRNA and the formation/stability of duplex via molecular dynamics study for a period of 15ns and (iv) characterization of mRNA-siRNA duplex stability based on thermo-physical analysis. The stable GC-rich siRNA expressed strong binding affinity towards mRNA and forms stable duplex in A-form. The linear dependence between the thermo-physical parameters such as Tm, GC content and binding free energy revealed the ability of the identified siRNAs to interact with mRNA in comparable to that of the experimentally reported siRNAs. Hence, this present study proposes few siRNAs as the possible gene silencing agents in RNAi therapy based on the in silico approach. PMID:26854610

  11. From dynamic combinatorial ‘hit’ to lead: in vitro and in vivo activity of compounds targeting the pathogenic RNAs that cause myotonic dystrophy

    PubMed Central

    Ofori, Leslie O.; Hoskins, Jason; Nakamori, Masayuki; Thornton, Charles A.; Miller, Benjamin L.

    2012-01-01

    The myotonic dystrophies (DM) are human diseases in which the accumulation of toxic RNA (CUG or CCUG) repeats in the cell causes sequestration of splicing factors, including MBNL1, leading to clinical symptoms such as muscle wasting and myotonia. We previously used Dynamic Combinatorial Chemistry to identify the first compounds known to inhibit (CUG)-MBNL1 binding in vitro. We now report transformation of those compounds into structures with activity in vivo. Introduction of a benzo[g]quinoline substructure previously unknown in the context of RNA recognition, as well as other modifications, provided several molecules with enhanced binding properties, including compounds with strong selectivity for CUG repeats over CAG repeats or CAG–CUG duplex RNA. Compounds readily penetrate cells, and improve luciferase activity in a mouse myoblast assay in which enzyme function is coupled to a release of nuclear CUG–RNA retention. Most importantly, two compounds are able to partially restore splicing in a mouse model of DM1. PMID:22492623

  12. Dynamics

    NASA Astrophysics Data System (ADS)

    Ransom, Barbara

    1984-04-01

    Dynamics!” she said, as she buried her head deep in a book on tectonics. “Must be the key to explain what we see the ignorance of which seems to be chronic.”Convection below, then density flow and phase changes are not withstanding; Thermal gradient change and compositional range are things our minds should be commanding.

  13. The reflectivity, wettability and scratch durability of microsurface features molded in the injection molding process using a dynamic tool tempering system

    NASA Astrophysics Data System (ADS)

    Kuhn, Sascha; Burr, August; Kübler, Michael; Deckert, Matthias; Bleesen, Christoph

    2011-02-01

    In this paper the replication qualities of periodically and randomly arranged micro-features molded in the injection molding process and their effects on surface properties are studied. The features are molded in PC, PMMA and PP at different mold wall temperatures in order to point out the necessity and profitability of a variotherm mold wall temperature control system. A one-dimensional heat conduction model is proposed to predict the cycle times of the variotherm injection molding processes. With regard to these processes, the molding results are compared to the molded surface feature heights using an atomic force microscope. In addition, the effects of the molded surface features on macroscopic surfaces are characterized in terms of light reflection using a spectrometer and in terms of water wettability by measuring the static contact angle. Furthermore, due to the sensitivity of the surface features on the molded parts, their durability is compared in a scratch test with a diamond tip. This leads to successful implementation in applications in which the optical appearance, in terms of gloss and reflection, and the water repellence, in terms of drag flow and adhesion, are of importance.

  14. General features

    SciTech Connect

    Wallace, R.E.

    1990-01-01

    The San Andreas fault system, a complex of faults that display predominantly large-scale strike slip, is part of an even more complex system of faults, isolated segments of the East Pacific Rise, and scraps of plates lying east of the East Pacific Rise that collectively separate the North American plate from the Pacific plate. This chapter briefly describes the San Andreas fault system, its setting along the Pacific Ocean margin of North America, its extent, and the patterns of faulting. Only selected characteristics are described, and many features are left for depictions on maps and figures.

  15. Ocean dynamic processes causing spatially heterogeneous distribution of sedimentary caesium-137 massively released from the Fukushima Dai-ichi Nuclear Power Plant

    NASA Astrophysics Data System (ADS)

    Higashi, H.; Morino, Y.; Furuichi, N.; Ohara, T.

    2015-08-01

    Massive amounts of anthropogenic radiocaesium 137Cs that was released into the environment by the Fukushima Dai-ichi Nuclear Power Plant accident on March 2011 are widely known to have extensively migrated to Pacific oceanic sediment off of east Japan. Several recent reports have stated that the sedimentary 137Cs is now stable with a remarkably heterogeneous distribution. The present study elucidates ocean dynamic processes causing this heterogeneous sedimentary 137Cs distribution in and around the shelf off Fukushima and adjacent prefectures. We performed a numerical simulation of oceanic 137Cs behaviour for about 10 months after the accident, using a comprehensive dynamic model involving advection-diffusion transport in seawater, adsorption and desorption to and from particulate matter, sedimentation and suspension on and from the bottom, and vertical diffusion transport in the sediment. A notable simulated result was that the sedimentary 137Cs significantly accumulated in a swath just offshore of the shelf break (along the 50-100 m isobath) as in recent observations, although the seabed in the entire simulation domain was assumed to have ideal properties such as identical bulk density, uniform porosity, and aggregation of particles with a single grain diameter. This result indicated that the heterogeneous sedimentary 137Cs distribution was not necessarily a result of the spatial distribution of 137Cs sediment adsorptivity. The present simulation suggests that the shape of the swath is mainly associated with spatiotemporal variation between bottom shear stress in the shallow shelf (< 50 m depths) and that offshore of the shelf break. In a large part of the shallow shelf, the simulation indicated that strong bottom friction suspending particulate matter from the seabed frequently occurred via a periodic spring tide about every 2 weeks and via occasional strong wind. The sedimentary 137Cs thereby could hardly stay on the surface of the seabed with the result that

  16. Deletion of 4.4 Mb at 2q33.2q33.3 May Cause Growth Deficiency in a Patient with Mental Retardation, Facial Dysmorphic Features and Speech Delay.

    PubMed

    Papoulidis, Ioannis; Paspaliaris, Vassilis; Papageorgiou, Elena; Siomou, Elissavet; Dagklis, Themistoklis; Sotiriou, Sotirios; Thomaidis, Loretta; Manolakos, Emmanouil

    2015-01-01

    A patient with a rare interstitial deletion of chromosomal band 2q33.2q33.3 is described. The clinical features resembled the 2q33.1 microdeletion syndrome (Glass syndrome), including mental retardation, facial dysmorphism, high-arched narrow palate, growth deficiency, and speech delay. The chromosomal aberration was characterized by whole genome BAC aCGH. A comparison of the current patient and Glass syndrome features revealed that this case displayed a relatively mild phenotype. Overall, it is suggested that the deleted region of 2q33 causative for Glass syndrome may be larger than initially suggested. PMID:25925190

  17. Flexible Feature-Based Inhibition in Visual Search Mediates Magnified Impairments of Selection: Evidence from Carry-Over Effects under Dynamic Preview-Search Conditions

    ERIC Educational Resources Information Center

    Andrews, Lucy S.; Watson, Derrick G.; Humphreys, Glyn W.; Braithwaite, Jason J.

    2011-01-01

    Evidence for inhibitory processes in visual search comes from studies using preview conditions, where responses to new targets are delayed if they carry a featural attribute belonging to the old distractor items that are currently being ignored--the negative carry-over effect (Braithwaite, Humphreys, & Hodsoll, 2003). We examined whether…

  18. Did clockwise rotation of Antarctica cause the break-up of Gondwanaland? An investigation in the 'deep-keeled cratons' frame for global dynamics

    NASA Astrophysics Data System (ADS)

    Osmaston, M. F.

    2012-04-01

    Introduction. The 'deep-keeled cratons' frame for global dynamics is the result of seeking Earth-behaviour answers to the following outside-the-box proposition:- "If cratons have tectospheric keels that reach or approach the 660 km discontinuity, AND the 660 level is an effective barrier to mantle circulation, then obviously (i) when two cratons separate, the upper mantle to put under the nascent ocean must arrive by a circuitous route and, conversely, (ii) if they approach one another, the mantle volume that was in between them must get extruded sideways." Surprisingly it has turned out [1 - 4] that Earth dynamical behaviour for at least the past 150 Ma provides persuasive affirmation of both these expectations and that there is a rational petrological explanation for the otherwise-unexpected immobility of subcratonic material to such depths [5 - 7]. Clockwise rotation of Antarctica? This contribution greatly amplifies my original plate dynamical arguments for suggesting [8] that such rotation is ongoing. Convection is unsuited to causing rotation about a pole within the plate so, as noted then, a gearwheel-like linkage to Africa at the SWIR would provide its clearly CCW (Biscay-Caucasus) relationship to the Mediterranean belt for the past 100 Ma, also seen in its separation from South America. Gearwheel-like linkage of motion requires the presence of some kind of E-W restraint further north. In that case it was the N Africa/Arabia involvement in the Alpide belt, but the earlier opening of the central Atlantic by the eastward motion of Africa, suggests its rigid Gondwanan attachment to Antarctica rotation at that time, with little constraint in the north. Further east, the seafloor data show that Australia-Antarctica separation involved no such opposite rotational linkage, so, with no E-W mechanical constraint in the north by Indonesia, they must have rotated together, as is recorded by Australia's eastward motion to generate the Mesozoic seafloor at its western

  19. A Computer-Aided Diagnosis System for Dynamic Contrast-Enhanced MR Images Based on Level Set Segmentation and ReliefF Feature Selection

    PubMed Central

    Zhu, Dongmei; Li, Li

    2015-01-01

    This study established a fully automated computer-aided diagnosis (CAD) system for the classification of malignant and benign masses via breast magnetic resonance imaging (BMRI). A breast segmentation method consisting of a preprocessing step to identify the air-breast interfacing boundary and curve fitting for chest wall line (CWL) segmentation was included in the proposed CAD system. The Chan-Vese (CV) model level set (LS) segmentation method was adopted to segment breast mass and demonstrated sufficiently good segmentation performance. The support vector machine (SVM) classifier with ReliefF feature selection was used to merge the extracted morphological and texture features into a classification score. The accuracy, sensitivity, and specificity measurements for the leave-half-case-out resampling method were 92.3%, 98.2%, and 76.2%, respectively. For the leave-one-case-out resampling method, the measurements were 90.0%, 98.7%, and 73.8%, respectively. PMID:25628755

  20. Time variant analysis of large scale constrained rotorcraft systems dynamics - An exploitation of IBM-3090 vector-processor's pipe-lining feature

    NASA Technical Reports Server (NTRS)

    Amirouche, F. M. L.; Shareef, N. H.; Xie, M.

    1991-01-01

    A generalized algorithmic procedure is presented for handling the constraints in transmissions, which are treated as a multibody system of interconnected rigid/flexible bodies. The type of constraints are classified based on the interconnection of the bodies, assuming one or more points of contact to exist between them. The method is explained through flow charts and configuration/interaction tables. A significant increase in speed of execution is achieved by vectorizing the developed code in computationally intensive areas. The study of an example consisting of two meshing disks rotating at high angular velocity is carried out. The dynamic behavior of the constraint forces associated with the generalized coordinates of the system are plotted by selecting various modes. Applications are intended for the study of dynamic and subsequent prediction of constraint forces at the gear teeth contacting points in helicopter transmissions with the aim of improving performance dependability.

  1. Gas-dynamic signs of explosive eruptions of volcanoes. 2. Model of homogeneous-heterogeneous nucleation. Specific features of destruction of the cavitating magma

    NASA Astrophysics Data System (ADS)

    Kedrinskii, V. K.

    2009-03-01

    The dynamics of state of the crystallite-containing magma is studied within the framework of the gas-dynamic model of bubble cavitation. The effect of crystallites on flow evolution is considered for two cases: where the crystallites are cavitation nuclei (homogeneous-heterogeneous nucleation model) and where large clusters of crystallites are formed in the magma in the period between eruptions. In the first case, decompression jumps are demonstrated to arise as early as in the wave precursor; the intensity of these jumps turns out to be sufficient to form a series of discrete zones of nucleation ahead of the front of the main decompression wave. Results of experimental modeling of an explosive eruption with ejection of crystallite clusters (magmatic “bombs”) suggest that a cocurrent flow of the cavitating magma with dynamically varying properties (mean density and viscosity) transforms to an independent unsteady flow whose velocity is greater than the magma flow velocity. Experimental results on modeling the flow structure during the eruption show that coalescence of bubbles in the flow leads to the formation of spatial “slugs” consisting of the gas and particles. This process is analyzed within a combined nucleation model including the two-phase Iordansky-Kogarko-van Wijngaarden model and the model of the “frozen” field of mass velocities in the cavitation zone.

  2. Special Feature: Constraints on nebular dynamics and chemistry based on observations of annealed magnesium silicate grains in comets and in disks surrounding Herbig Ae/Be stars

    NASA Astrophysics Data System (ADS)

    Hill, Hugh G. M.; Grady, Carol A.; Nuth, Joseph A., III; Hallenbeck, Susan L.; Sitko, Michael L.

    2001-02-01

    Understanding dynamic conditions in the Solar Nebula is the key to prediction of the material to be found in comets. We suggest that a dynamic, large-scale circulation pattern brings processed dust and gas from the inner nebula back out into the region of cometesimal formationextending possibly hundreds of astronomical units (AU) from the sunand that the composition of comets is determined by a chemical reaction network closely coupled to the dynamic transport of dust and gas in the system. This scenario is supported by laboratory studies of Mg silicates and the astronomical data for comets and for protoplanetary disks associated with young stars, which demonstrate that annealing of nebular silicates must occur in conjunction with a large-scale circulation. Mass recycling of dust should have a significant effect on the chemical kinetics of the outer nebula by introducing reduced, gas-phase species produced in the higher temperature and pressure environment of the inner nebula, along with freshly processed grains with "clean" catalytic surfaces to the region of cometesimal formation. Because comets probably form throughout the lifetime of the Solar Nebula and processed (crystalline) grains are not immediately available for incorporation into the first generation of comets, an increasing fraction of dust incorporated into a growing comet should be crystalline olivine and this fraction can serve as a crude chronometer of the relative ages of comets. The formation and evolution of key organic and biogenic molecules in comets are potentially of great consequence to astrobiology.

  3. Mechanisms of Disease and Clinical Features of Mutations of the Gene for Mitofusin 2: An Important Cause of Hereditary Peripheral Neuropathy with Striking Clinical Variability in Children and Adults

    ERIC Educational Resources Information Center

    Ouvrier, Robert; Grew, Simon

    2010-01-01

    Mitofusin 2, a large transmembrane GTPase located in the outer mitochondrial membrane, promotes membrane fusion and is involved in the maintenance of the morphology of axonal mitochondria. Mutations of the gene encoding mitofusin 2 ("MFN2") have recently been identified as the cause of approximately one-third of dominantly inherited cases of the…

  4. Did clockwise rotation of Antarctica cause the break-up of Gondwanaland? An investigation in the 'deep-keeled cratons' frame for global dynamics

    NASA Astrophysics Data System (ADS)

    Osmaston, M. F.

    2012-04-01

    Introduction. The 'deep-keeled cratons' frame for global dynamics is the result of seeking Earth-behaviour answers to the following outside-the-box proposition:- "If cratons have tectospheric keels that reach or approach the 660 km discontinuity, AND the 660 level is an effective barrier to mantle circulation, then obviously (i) when two cratons separate, the upper mantle to put under the nascent ocean must arrive by a circuitous route and, conversely, (ii) if they approach one another, the mantle volume that was in between them must get extruded sideways." Surprisingly it has turned out [1 - 4] that Earth dynamical behaviour for at least the past 150 Ma provides persuasive affirmation of both these expectations and that there is a rational petrological explanation for the otherwise-unexpected immobility of subcratonic material to such depths [5 - 7]. Clockwise rotation of Antarctica? This contribution greatly amplifies my original plate dynamical arguments for suggesting [8] that such rotation is ongoing. Convection is unsuited to causing rotation about a pole within the plate so, as noted then, a gearwheel-like linkage to Africa at the SWIR would provide its clearly CCW (Biscay-Caucasus) relationship to the Mediterranean belt for the past 100 Ma, also seen in its separation from South America. Gearwheel-like linkage of motion requires the presence of some kind of E-W restraint further north. In that case it was the N Africa/Arabia involvement in the Alpide belt, but the earlier opening of the central Atlantic by the eastward motion of Africa, suggests its rigid Gondwanan attachment to Antarctica rotation at that time, with little constraint in the north. Further east, the seafloor data show that Australia-Antarctica separation involved no such opposite rotational linkage, so, with no E-W mechanical constraint in the north by Indonesia, they must have rotated together, as is recorded by Australia's eastward motion to generate the Mesozoic seafloor at its western

  5. A study of the clinical and radiological features in a cohort of 93 patients with a COL2A1 mutation causing spondyloepiphyseal dysplasia congenita or a related phenotype.

    PubMed

    Terhal, Paulien A; Nievelstein, Rutger Jan A J; Verver, Eva J J; Topsakal, Vedat; van Dommelen, Paula; Hoornaert, Kristien; Le Merrer, Martine; Zankl, Andreas; Simon, Marleen E H; Smithson, Sarah F; Marcelis, Carlo; Kerr, Bronwyn; Clayton-Smith, Jill; Kinning, Esther; Mansour, Sahar; Elmslie, Frances; Goodwin, Linda; van der Hout, Annemarie H; Veenstra-Knol, Hermine E; Herkert, Johanna C; Lund, Allan M; Hennekam, Raoul C M; Mégarbané, André; Lees, Melissa M; Wilson, Louise C; Male, Alison; Hurst, Jane; Alanay, Yasemin; Annerén, Göran; Betz, Regina C; Bongers, Ernie M H F; Cormier-Daire, Valerie; Dieux, Anne; David, Albert; Elting, Mariet W; van den Ende, Jenneke; Green, Andrew; van Hagen, Johanna M; Hertel, Niels Thomas; Holder-Espinasse, Muriel; den Hollander, Nicolette; Homfray, Tessa; Hove, Hanne D; Price, Susan; Raas-Rothschild, Annick; Rohrbach, Marianne; Schroeter, Barbara; Suri, Mohnish; Thompson, Elizabeth M; Tobias, Edward S; Toutain, Annick; Vreeburg, Maaike; Wakeling, Emma; Knoers, Nine V; Coucke, Paul; Mortier, Geert R

    2015-03-01

    Type 2 collagen disorders encompass a diverse group of skeletal dysplasias that are commonly associated with orthopedic, ocular, and hearing problems. However, the frequency of many clinical features has never been determined. We retrospectively investigated the clinical, radiological, and genotypic data in a group of 93 patients with molecularly confirmed SEDC or a related disorder. The majority of the patients (80/93) had short stature, with radiological features of SEDC (n = 64), others having SEMD (n = 5), Kniest dysplasia (n = 7), spondyloperipheral dysplasia (n = 2), or Torrance-like dysplasia (n = 2). The remaining 13 patients had normal stature with mild SED, Stickler-like syndrome or multiple epiphyseal dysplasia. Over 50% of the patients had undergone orthopedic surgery, usually for scoliosis, femoral osteotomy or hip replacement. Odontoid hypoplasia was present in 56% (95% CI 38-74) and a correlation between odontoid hypoplasia and short stature was observed. Atlanto-axial instability, was observed in 5 of the 18 patients (28%, 95% CI 10-54) in whom flexion-extension films of the cervical spine were available; however, it was rarely accompanied by myelopathy. Myopia was found in 45% (95% CI 35-56), and retinal detachment had occurred in 12% (95% CI 6-21; median age 14 years; youngest age 3.5 years). Thirty-two patients complained of hearing loss (37%, 95% CI 27-48) of whom 17 required hearing aids. The ophthalmological features and possibly also hearing loss are often relatively frequent and severe in patients with splicing mutations. Based on clinical findings, age at onset and genotype-phenotype correlations in this cohort, we propose guidelines for the management and follow-up in this group of disorders. PMID:25604898

  6. Dynamic analysis of changing features of tumor cells incubated with antitumor agents in vitro and its application for predictive activity assay of antitumor agents.

    PubMed

    Oguro, M; Takagi, T; Takenaga, K

    1985-02-01

    Continuous observation of living malignant cells (L1210) in a specially devised glass observation chamber with an inverted microscope made it possible to classify various cellular morphological features induced by antitumor agents into the following four stages: 1) an initial stage consisting of cytoplasmic granulation and coloring, 2) an intermediate stage of shrinkage of nuclei, increases of vacuoles and cytoplasmic budding, 3) a determinate stage of cell ballooning and 4) the terminal stage (cell ghost). Both the initial and intermediate stages are characterized by cellular changes that appear at an early phase and remain opportunistic in terms of viability. Emergence of these cellular changes is largely dependent on the specific mode of action of antitumor agents. In contrast, definite irreversibility in the changes found in both the terminal and determinate stages was confirmed by continuous observation until the cells showed lytic or ghost features, using a video-recording system. A plot of the number of cells counted in both the determinate and terminal stages versus the time-dose schedule is designated as the "time-dose-response" plot, and this proved useful for estimating the characteristics of the antitumor agents tested and the actions of new antitumor agents on malignant cells (predictive activity assay graph). PMID:3920102

  7. Hydrochemistry dynamics in remote mountain lakes and its relation to catchment and atmospheric features: the case study of Sabocos Tarn, Pyrenees.

    PubMed

    Santolaria, Zoe; Arruebo, Tomas; Urieta, José Santiago; Lanaja, Francisco Javier; Pardo, Alfonso; Matesanz, José; Rodriguez-Casals, Carlos

    2015-01-01

    Increasing the understanding of high mountain lake dynamics is essential to use these remote aquatic ecosystems as proxies of global environmental changes. With this aim, at Sabocos, a Pyrenean cirque glacial lake or tarn, this study shows the main results of a morphological and catchment characterization, along with statistical analyses of its hydrochemical trends and their concomitant driving factors from 2010 to 2013. Dissolved oxygen, water temperature stratification, and its snow and ice cover composition and dynamics have been also investigated. According to morphological analyses, Sabocos can be classified as a medium-large and deep lake, having a circular contour and a long water retention time as compared to Pyrenean glacial lake average values. Sabocos hydrochemistry is mainly determined by very high alkalinity, pH and conductivity levels, and high Ca(2+), Mg(2+), and SO4(2-) content, coming from the easily weatherable limestone-dolomite bedrock. Thus, lake water is well buffered, and therefore, Sabocos tarn is non-sensitive to acidification processes. On the other hand, the main source of K(+), Na(+), and Cl(-) (sea salts) and nutrients (NH4(+), NO3(-), and phosphorous) to lake water appears to be atmospheric deposition. Primary production is phosphorous limited, and due to the N-saturation stage of the poorly developed soils of Sabocos catchment, NO3(-) is the chief component in the total nitrogen pool. External temperature seems to be the major driver regulating lake productivity, since warm temperatures boot primary production. Although precipitation might also play an important role in lake dynamics, especially regarding to those parameters influenced by the weathering of the bedrock, its influence cannot be easily assessed due to the seasonal isolation produced by the ice cover. Also, as occurs in the whole Pyrenean lake district, chemical composition of bulk deposition is highly variable due to the contribution of air masses with different origin

  8. Effects of bursting dynamic features on the generation of multi-clustered structure of neural network with symmetric spike-timing-dependent plasticity learning rule.

    PubMed

    Liu, Hui; Song, Yongduan; Xue, Fangzheng; Li, Xiumin

    2015-11-01

    In this paper, the generation of multi-clustered structure of self-organized neural network with different neuronal firing patterns, i.e., bursting or spiking, has been investigated. The initially all-to-all-connected spiking neural network or bursting neural network can be self-organized into clustered structure through the symmetric spike-timing-dependent plasticity learning for both bursting and spiking neurons. However, the time consumption of this clustering procedure of the burst-based self-organized neural network (BSON) is much shorter than the spike-based self-organized neural network (SSON). Our results show that the BSON network has more obvious small-world properties, i.e., higher clustering coefficient and smaller shortest path length than the SSON network. Also, the results of larger structure entropy and activity entropy of the BSON network demonstrate that this network has higher topological complexity and dynamical diversity, which benefits for enhancing information transmission of neural circuits. Hence, we conclude that the burst firing can significantly enhance the efficiency of clustering procedure and the emergent clustered structure renders the whole network more synchronous and therefore more sensitive to weak input. This result is further confirmed from its improved performance on stochastic resonance. Therefore, we believe that the multi-clustered neural network which self-organized from the bursting dynamics has high efficiency in information processing. PMID:26627568

  9. Effects of bursting dynamic features on the generation of multi-clustered structure of neural network with symmetric spike-timing-dependent plasticity learning rule

    SciTech Connect

    Liu, Hui; Song, Yongduan; Xue, Fangzheng; Li, Xiumin

    2015-11-15

    In this paper, the generation of multi-clustered structure of self-organized neural network with different neuronal firing patterns, i.e., bursting or spiking, has been investigated. The initially all-to-all-connected spiking neural network or bursting neural network can be self-organized into clustered structure through the symmetric spike-timing-dependent plasticity learning for both bursting and spiking neurons. However, the time consumption of this clustering procedure of the burst-based self-organized neural network (BSON) is much shorter than the spike-based self-organized neural network (SSON). Our results show that the BSON network has more obvious small-world properties, i.e., higher clustering coefficient and smaller shortest path length than the SSON network. Also, the results of larger structure entropy and activity entropy of the BSON network demonstrate that this network has higher topological complexity and dynamical diversity, which benefits for enhancing information transmission of neural circuits. Hence, we conclude that the burst firing can significantly enhance the efficiency of clustering procedure and the emergent clustered structure renders the whole network more synchronous and therefore more sensitive to weak input. This result is further confirmed from its improved performance on stochastic resonance. Therefore, we believe that the multi-clustered neural network which self-organized from the bursting dynamics has high efficiency in information processing.

  10. Effects of bursting dynamic features on the generation of multi-clustered structure of neural network with symmetric spike-timing-dependent plasticity learning rule

    NASA Astrophysics Data System (ADS)

    Liu, Hui; Song, Yongduan; Xue, Fangzheng; Li, Xiumin

    2015-11-01

    In this paper, the generation of multi-clustered structure of self-organized neural network with different neuronal firing patterns, i.e., bursting or spiking, has been investigated. The initially all-to-all-connected spiking neural network or bursting neural network can be self-organized into clustered structure through the symmetric spike-timing-dependent plasticity learning for both bursting and spiking neurons. However, the time consumption of this clustering procedure of the burst-based self-organized neural network (BSON) is much shorter than the spike-based self-organized neural network (SSON). Our results show that the BSON network has more obvious small-world properties, i.e., higher clustering coefficient and smaller shortest path length than the SSON network. Also, the results of larger structure entropy and activity entropy of the BSON network demonstrate that this network has higher topological complexity and dynamical diversity, which benefits for enhancing information transmission of neural circuits. Hence, we conclude that the burst firing can significantly enhance the efficiency of clustering procedure and the emergent clustered structure renders the whole network more synchronous and therefore more sensitive to weak input. This result is further confirmed from its improved performance on stochastic resonance. Therefore, we believe that the multi-clustered neural network which self-organized from the bursting dynamics has high efficiency in information processing.

  11. Birth dates vary with fixed and dynamic maternal features, offspring sex, and extreme climatic events in a high-latitude marine mammal.

    PubMed

    Rotella, Jay J; Paterson, J Terrill; Garrott, Robert A

    2016-04-01

    Reproductive synchrony tends to be widespread in diverse species of plants and animals, especially at higher latitudes. However, for long-lived mammals, birth dates for different individuals can vary by weeks within a population. A mother's birth timing can reveal useful information about her reproductive abilities and have important implications for the characteristics and survival of her offspring. Despite this, our current knowledge of factors associated with variation in birth dates is modest. We used long-term data for known-age Weddell seals in Antarctica and a Bayesian hierarchical modeling approach to study how birth dates varied with fixed and temporally varying features of mothers, whether sex allocation varied with birth timing, and annual variation in birth dates. Based on birth dates for 4465 pups born to 1117 mothers aged 4-31, we found that diverse features of mothers were associated with variation in birth dates. Maternal identity was the most important among these. Unlike most studies, which have reported that birth dates occur earlier as mothers age, we found that birth dates progressively occurred earlier in the year in the early part of a mother's reproductive life, reached a minimum at age 16, and then occurred later at later ages. Birth dates were positively related to a mother's age at primiparity and recent reproductive effort. The earliest birth dates were for pups born to prime-age mothers who did not reproduce in the previous year but began reproduction early in life, suggesting that females in the best condition gave birth earlier than others. If so, our finding that male pups tended to be born earlier than females provides support for the Trivers-Willard sex-allocation model. Average birth dates were quite consistent across years, except for 2 years that had notable delays and occurred during the period when massive icebergs were present and disrupted the ecosystem. PMID:27099704

  12. Jaundice causes

    MedlinePlus

    ... liver is unable to properly move into the digestive tract. Conditions that can cause jaundice include: Infections of the liver from a virus ( hepatitis A , hepatitis B , hepatitis C , hepatitis D , ...

  13. On structural features of fullerene C60 dissolved in carbon disulfide: complementary study by small-angle neutron scattering and molecular dynamic simulations.

    PubMed

    Avdeev, M V; Tropin, T V; Bodnarchuk, I A; Yaradaikin, S P; Rosta, L; Aksenov, V L; Bulavin, L A

    2010-04-28

    The parameters of fullerene C(60) dissolved in carbon disulfide CS(2) are analyzed by small-angle neutron scattering (SANS) in a wide interval of momentum transfer. To exclude the influence of nonequilibrium conditions, the solutions are prepared without applying shaking, stirring or ultrasound. No indication of the equilibrium cluster state of C(60) (with the cluster size below 60 nm) in the final solutions is revealed. Molecular dynamic simulations are complementary used to find out the partial volume of C(60) in CS(2) and the scattering contribution of the solvent organization at the interface with the fullerene molecule, which is shown to be small. Among several approaches for describing SANS data the preference is given to the model, which takes into account the presence of stable C(60) dimers (comprising 10% of the total particle number density) in the solution. PMID:20441296

  14. CO2-TEA mid-infrared laser-based DIAL system: featuring urban atmosphere ozone dynamics during a vehicle-free day

    NASA Astrophysics Data System (ADS)

    Gasmi, Taieb

    2002-09-01

    Long-path ozone integrated measurements with a CO2-laser DIAL system were performed in Madrid City during the 'vehicle-free' day. The results showed a strong correlation between human activity and ozone photochemical generation. The ozone concentration follows, even quantitatively, the same trend of the overall traffic intensity as long as both the UVB radiation and NO2 are present. An average decrease of 12.3 +/- 1.2 % of the intensity of vehicle traffic during the 'free-vehicle' day resulted in a lowering the ozone burden by almost 14.4 +/- 1.4 % . This new type of information can stimulate the development of local models to understand the dynamic underlying urban pollution. The results indeed show the effectiveness of such a measure as to reduce the ozone burden on human and plants health.

  15. Some features of the ecology of fleas inhabiting the nests of the suslik (Citellus citellus (L.)). I: Population dynamics, sex ratio, feeding, reproduction.

    PubMed

    Ryba, J; Rödl, P; Bartos, L; Daniel, M; Cerný, V

    1986-01-01

    While studying the suslik fleas in artificial nests planted in free nature, significant changes in the population dynamics of N. setosa, C. simplex and C. orientalis (from the spring build up to the autumnal peak and the decrease of flea number until the next spring) were noted. The predominance of females in the spring period was recorded in N. setosa. Significant seasonal changes in the number of engorged females of N. setosa and C. simplex and of C. orientalis males (the increase of engorged specimens in the spring and summer) were demonstrated. A significant predominance of females with mature eggs in the spring and summer and their negligible number in the autumn were found in N. setosa and C. simplex. PMID:3758870

  16. Dynamics of Back Electron Transfer in Dye-Sensitized Solar Cells Featuring 4-tert-Butyl-Pyridine and Atomic-Layer-Deposited Alumina as Surface Modifiers.

    PubMed

    Katz, Michael J; Vermeer, Michael J DeVries; Farha, Omar K; Pellin, Michael J; Hupp, Joseph T

    2015-06-18

    A series of dye-sensitized solar cells (DSCs) was constructed with TiO2 nanoparticles and N719 dye. The standard I3(-)/I(-) redox shuttle and the Co(1,10-phenanthroline)3(3+/2+) shuttle were employed. DSCs were modified with atomic-layered-deposited (ALD) coatings of Al2O3 and/or with the surface-adsorbing additive 4-tert-butyl-pyridine. Current-voltage data were collected to ascertain the influence of each modification upon the back electron transfer (ET) dynamics of the DSCs. The primary effect of the additives alone or in tandem is to increase the open-circuit voltage. A second is to alter the short-circuit current density, JSC. With dependence on the specifics of the system examined, any of a myriad of dynamics-related effects were observed to come into play, in both favorable (efficiency boosting) and unfavorable (efficiency damaging) ways. These effects include modulation of (a) charge-injection yields, (b) rates of interception of injected electrons by redox shuttles, and (c) rates of recombination of injected electrons with holes on surface-bound dyes. In turn, these influence charge-collection lengths, charge-collection yields, and onset potentials for undesired dark current. The microscopic origins of the effects appear to be related mainly to changes in driving force and/or electronic coupling for underlying component redox reactions. Perhaps surprisingly, only a minor role for modifier-induced shifts in conduction-band-edge energy was found. The combination of DSC-efficiency-relevant effects engendered by the modifiers was found to vary substantially as a function of the chemical identity of the redox shuttle employed. While types of modifiers are effective, a challenge going forward will be to construct systems in ways in which the benefits of organic and inorganic modifiers can be exploited in fully additive, or even synergistic, fashion. PMID:25127076

  17. Intrinsic Feature Motion Tracking

    Energy Science and Technology Software Center (ESTSC)

    2013-03-19

    Subject motion during 3D medical scanning can cause blurring and artifacts in the 3D images resulting in either rescans or poor diagnosis. Anesthesia or physical restraints may be used to eliminate motion but are undesirable and can affect results. This software measures the six degree of freedom 3D motion of the subject during the scan under a rigidity assumption using only the intrinsic features present on the subject area being monitored. This movement over timemore » can then be used to correct the scan data removing the blur and artifacts. The software acquires images from external cameras or images stored on disk for processing. The images are from two or three calibrated cameras in a stereo arrangement. Algorithms extract and track the features over time and calculate position and orientation changes relative to an initial position. Output is the 3D position and orientation change measured at each image.« less

  18. Intrinsic Feature Motion Tracking

    SciTech Connect

    Goddard, Jr., James S.

    2013-03-19

    Subject motion during 3D medical scanning can cause blurring and artifacts in the 3D images resulting in either rescans or poor diagnosis. Anesthesia or physical restraints may be used to eliminate motion but are undesirable and can affect results. This software measures the six degree of freedom 3D motion of the subject during the scan under a rigidity assumption using only the intrinsic features present on the subject area being monitored. This movement over time can then be used to correct the scan data removing the blur and artifacts. The software acquires images from external cameras or images stored on disk for processing. The images are from two or three calibrated cameras in a stereo arrangement. Algorithms extract and track the features over time and calculate position and orientation changes relative to an initial position. Output is the 3D position and orientation change measured at each image.

  19. Dynamics of States in the Nonlinear Interaction Regime Between a Three-Level Atom and Generalized Coherent States and Their Non-Classical Features

    NASA Astrophysics Data System (ADS)

    Tavassoly, M. K.; Yadollahi, F.

    The present study investigates the interaction of an equidistant three-level atom and a single-mode cavity field that has been initially prepared in a generalized coherent state. The atom-field interaction is considered to be, in general, intensity-dependent. We suppose that the nonlinearity of the initial generalized coherent state of the field and the intensity-dependent coupling between atom and field are distinctly chosen. Interestingly, an exact analytical solution for the time evolution of the state of atom-field system can be found in this general regime in terms of the nonlinearity functions. Finally, the presented formalism has been applied to a few known physical systems such as Gilmore-Perelomov and Barut-Girardello coherent states of SU(1,1) group, as well as a few special cases of interest. Mean photon number and atomic population inversion will be calculated, in addition to investigating particular non-classicality features such as revivals, sub-Poissonian statistics and quadratures squeezing of the obtained states of the entire system. Also, our results will be compared with some of the earlier works in this particular subject.

  20. Spatial and temporal dynamics of biotic and abiotic features of temperate coastal ecosystems as revealed by a combination of ecological indicators

    NASA Astrophysics Data System (ADS)

    Grangeré, K.; Lefebvre, S.; Blin, J.-L.

    2012-08-01

    Coastal ecosystems exhibit complex spatio-temporal patterns due to their position at the interface between land and sea. This is particularly the case of temperate ecosystems where exploitation of coastal resources (fisheries and aquaculture) and intensive agricultural use of watersheds further complicate our understanding of their dynamics. The aim of the present study was to unravel the spatio-temporal dynamics of contrasted megatidal coastal ecosystems located at the same regional scale (i.e. under the same regional climate), but under different kinds of human pressure. Two kinds of ecological indicators were assessed over a period of four years at 11 locations along the coast of the Cotentin peninsula (Normandy, France). A first set of hydrobiological variables (dissolved nutrients, Chl a, temperature, salinity, etc.) was measured fortnightly in the water column. These data were analysed by principal components analysis (PCA). A second set of variables were the carbon and nitrogen stable isotope ratios of the adductor muscles of cultured Crassostrea gigas introduced every year to typify the bentho-pelagic coupling at each location. Food sources were also investigated using a mixing model with data on the isotopic composition of the food sources obtained previously. To identify which environmental variables played a significant role in determining the oyster diet, the contributions of oyster food sources were combined with environmental variables in a canonical correspondence analysis (CCA). Isotopic values of adductor muscles varied significantly between -20.12‰ and -16.79‰ for δ13C and between 8.28‰ and 11.87‰ for δ15N. The PCA distinguished two groups of coastal ecosystems that differed in their coastal hydrology, nutrient inputs, and the size of their respective watershed, irrespective of the year. In each zone, different spatial patterns in the measured variables were observed depending on the year showing that local impacts differed temporally

  1. Feature integration across space, time, and orientation

    PubMed Central

    Otto, Thomas U.; Öğmen, Haluk; Herzog, Michael H.

    2012-01-01

    The perception of a visual target can be strongly influenced by flanking stimuli. In static displays, performance on the target improves when the distance to the flanking elements increases- proposedly because feature pooling and integration vanishes with distance. Here, we studied feature integration with dynamic stimuli. We show that features of single elements presented within a continuous motion stream are integrated largely independent of spatial distance (and orientation). Hence, space based models of feature integration cannot be extended to dynamic stimuli. We suggest that feature integration is guided by perceptual grouping operations that maintain the identity of perceptual objects over space and time. PMID:19968428

  2. Feature Integration across Space, Time, and Orientation

    ERIC Educational Resources Information Center

    Otto, Thomas U.; Ogmen, Haluk; Herzog, Michael H.

    2009-01-01

    The perception of a visual target can be strongly influenced by flanking stimuli. In static displays, performance on the target improves when the distance to the flanking elements increases--presumably because feature pooling and integration vanishes with distance. Here, we studied feature integration with dynamic stimuli. We show that features of…

  3. Universal Features of Electron Dynamics in Solar Cells with TiO2 Contact: From Dye Solar Cells to Perovskite Solar Cells.

    PubMed

    Todinova, Anna; Idígoras, Jesús; Salado, Manuel; Kazim, Samrana; Anta, Juan A

    2015-10-01

    The electron dynamics of solar cells with mesoporous TiO2 contact is studied by electrochemical small-perturbation techniques. The study involved dye solar cells (DSC), solid-state perovskite solar cells (SSPSC), and devices where the perovskite acts as sensitizer in a liquid-junction device. Using a transport-recombination continuity equation we found that mid-frequency time constants are proper lifetimes that determine the current-voltage curve. This is not the case for the SSPSC, where a lifetime of ∼1 μs, 1 order of magnitude longer, is required to reproduce the current-voltage curve. This mismatch is attributed to the dielectric response on the mid-frequency component. Correcting for this effect, lifetimes lie on a common exponential trend with respect to open-circuit voltage. Electron transport times share a common trend line too. This universal behavior of lifetimes and transport times suggests that the main difference between the cells is the power to populate the mesoporous TiO2 contact with electrons. PMID:26704621

  4. Specific features of the dynamics of epiphytic and soil yeast communities in the thickets of Indian balsam on mucky gley soil

    NASA Astrophysics Data System (ADS)

    Glushakova, A. M.; Kachalkin, A. V.; Chernov, I. Yu.

    2011-08-01

    The annual dynamics of the number and taxonomic composition of yeast communities were studied in the phyllosphere, on the flowers, and on the roots of Indian balsam ( Impatiens glandulifera Royle) and in the mucky gley soil under the thickets of this plant. It was shown that typical phyllosphere yeast communities with a predominance of the red-pigmented species Rhodotorula mucilaginosa and Rhodotorula glutinis and the typical epiphyte Cryptococcus magnus are formed on the leaves of this annual hygrophyte. However, yeast groups with a predominance of the ascosporous species Saccharomyces paradoxus, Kazachstania barnettii, and Torulaspora delbrueckii, which are not typical of soils at all, were found in the mucky gley soil under the thickets of Indian balsam. Thus, the epiphytic and soil yeast complexes under the thickets of Indian balsam are represented by two entirely discrete communities without common species. In other biogeocenoses of the forest zone, the rearrangement of the structure of yeast communities in passing from the aboveground substrates to the soil proceeds gradually, and most of the species can be isolated both from the aboveground parts of plants and from the soil. The strong difference between the yeast communities in the phyllosphere of Indian balsam and in the soil under its thickets is apparently related to the fact that the annual hygrophytes are decomposed very quickly (during several days after the first frosts). Because of this, an intermediate layer between the phyllosphere and the soil (the litter layer), in which epiphytic microorganisms can develop, is not formed under these plants.

  5. Differential DNA methylation with age displays both common and dynamic features across human tissues that are influenced by CpG landscape

    PubMed Central

    2013-01-01

    Background DNA methylation is an epigenetic modification that changes with age in human tissues, although the mechanisms and specificity of this process are still poorly understood. We compared CpG methylation changes with age across 283 human blood, brain, kidney, and skeletal muscle samples using methylation arrays to identify tissue-specific age effects. Results We found age-associated CpGs (ageCGs) that are both tissue-specific and common across tissues. Tissue-specific ageCGs are frequently located outside CpG islands with decreased methylation, and common ageCGs show the opposite trend. AgeCGs are significantly associated with poorly expressed genes, but those with decreasing methylation are linked with higher tissue-specific expression levels compared with increasing methylation. Therefore, tissue-specific gene expression may protect against common age-dependent methylation. Distinguished from other tissues, skeletal muscle ageCGs are more associated with expression, enriched near genes related to myofiber contraction, and closer to muscle-specific CTCF binding sites. Kidney-specific ageCGs are more increasingly methylated compared to other tissues as measured by affiliation with kidney-specific expressed genes. Underlying chromatin features also mark common and tissue-specific age effects reflective of poised and active chromatin states, respectively. In contrast with decreasingly methylated ageCGs, increasingly methylated ageCGs are also generally further from CTCF binding sites and enriched within lamina associated domains. Conclusions Our data identified common and tissue-specific DNA methylation changes with age that are reflective of CpG landscape and suggests both common and unique alterations within human tissues. Our findings also indicate that a simple epigenetic drift model is insufficient to explain all age-related changes in DNA methylation. PMID:24034465

  6. Dynamics of the large-scale open solar magnetic field and its specific features in the zone of the main active longitudes in 2006-2012

    NASA Astrophysics Data System (ADS)

    Ivanov, K. G.; Kharshiladze, A. F.

    2013-11-01

    The dynamics of the absolute global values (Φ) of the large-scale open solar magnetic field (LOSMF) fluxes at an interval of one solar rotation in 2006-2012 has been studied based on the Wilcox Solar Observatory data and using the ISOPAK original package for modeling the solar magnetic field. The reference points and the duration of the final quasi-biennial interval in cycle 23 (January 2006-May 2007; 17 months) and the phases of the cycle 24 minimum (May 2007-November 2009; 30 months), growth (November 2009-May 2012; 30 months), and the beginning of the maximum (May 2012-January 2013) have been determined. It has been indicated that the absolute values (Φ) decreased sharply at the beginning of the minimum, growth, and the maximum phases to ˜(2, 1.25, 0.75) × 1022 Mx, respectively. During the entire minimum phase, LOSMF corotated super-quasi-rigidly westward in the direction of solar rotation; at the beginning of the growth phase, this field started corotating mostly eastward. The LOSMF polarity reversal in the current cycle 24 started in May-June 2012 (CR 2123-2124), when fields of southern polarity rushed from the Sun's southern hemisphere toward the north. The statement that the solar cycle is a continuous series of quasi-biennial LOSMF intervals is confirmed. In particular, the minimum and growth phases are characterized by opposite LOSMF rotation directions, i.e., super-quasi-rigid corotation (twisting) and detwisting, with identical duration at least in cycle 24.

  7. Dynamic and thermodynamic features of low and middle clouds derived from atmospheric radiation measurement program mobile facility radiosonde data at Shouxian, China

    NASA Astrophysics Data System (ADS)

    Zhang, Jinqiang; Chen, Hongbin; Xia, Xiang'ao; Wang, Wei-Chyung

    2016-01-01

    By using the radiosonde measurements collected at Shouxian, China, we examined the dynamics and thermodynamics of single- and two-layer clouds formed at low and middle levels. The analyses indicated that the horizontal wind speed above the cloud layers was higher than those within and below cloud layers. The maximum balloon ascent speed (5.3 m s-1) was located in the vicinity of the layer with the maximum cloud occurrence frequency (24.4%), indicating an upward motion (0.1-0.16 m s-1). The average thickness, magnitude and gradient of the temperature inversion layer above single-layer clouds were 117±94 m, 1.3±1.3°C and 1.4±1.5°C (100 m)-1, respectively. The average temperature inversion magnitude was the same (1.3°C) for single-low and single-middle clouds; however, a larger gradient [1.7±1.8°C (100 m)-1] and smaller thickness (94±67 m) were detected above single-low clouds relative to those above single-middle clouds [0.9±0.7°C (100 m)-1 and 157±120 m]. For the two-layer cloud, the temperature inversion parameters were 106±59 m, 1.0±0.9°C and 1.0±1.0°C (100 m)-1 above the upper-layer cloud and 82±60 m, 0.6±0.9°C and 0.7±0.6°C (100 m)-1 above the low-layer cloud. Absolute differences between the cloud-base height (cloud-top height) and the lifting condensation level (equilibrium level) were less than 0.5 km for 66.4% (36.8%) of the cases analyzed in summer.

  8. The composition of sedimentary organic matter in relation to the dynamic features of a mangrove-fringed coast in French Guiana

    NASA Astrophysics Data System (ADS)

    Marchand, C.; Lallier-Vergès, E.; Baltzer, F.

    2003-01-01

    The sedimentary organic matter content of a series of 2-m-deep cores was examined in relation to the evolution of mangrove forest, on the basis of geochemical analyses and optical observations. Avicennia-dominated forest deposits, developing along the highly dynamic coastline of French Guiana, were collected in five stations based on stage of forest evolution. The sedimentary organic matter in the upper sediment of the youngest mangrove swamp is mainly derived from algal mats with low carbon:nitrogen ratios (C:N ratio, from 6 to 8) and typical greyish amorphous organic flakes as observed in optical studies. Indeed, rare young Avicennia trees are present, and effectively, geochemical parameters do not give evidence of a litter made up of higher plant debris, these rare debris being probably exported by the tides. A slight increase with depth in the first decimetres of both total organic carbon (TOC) content and C:N ratio results from the development of the radial cable root-system of the pioneer Avicennia germinans. Early diagenetic conditions of this young forest are rather controlled by dominant suboxic processes, as suggested by high Eh values (range, 200-400 mV) and local anoxic processes (occurrence of pyrite) in micro-environments: this is mainly due to the oxygen available by roots and crab bioturbation. The organic content of the senescent mangrove sediment is mainly derived from higher plant debris in the uppermost 30 cm, as indicated by relatively high C:N ratios and the predominance of ligno-cellulosic debris. The strong decrease in hydrogen index values results from the degradation of the higher plant debris, losing hydrogen bounds through decay processes. Moderately acidic pH values, low Ehs and the presence of pyrite framboids point towards the reducing decay processes in surficial layers of the senescent mangrove mediated by sulphate-reducing bacteria. Whatever the stage of evolution of the forest, the geochemical characteristics of the sediment below

  9. The Unique Ability of the Electron-Positron (Epo) Lattice (Epola) Model of Space to Explain the Natural Causes of All Known Physical Features and Phenomena, Extrinsic to Nuclear Particles

    NASA Astrophysics Data System (ADS)

    Simhony, Menahem

    1999-10-01

    The binding energy _bE of an epo pair in the epola is 1.02 MeV. In an epola spot, deformed by a "guest" nucleus, such a quantum can be absorbed; this frees an epo pair off bonds, making it appear to our detection. The epo lattice constant is 4.4 fm, 50 R_e. Thus atomic bodies can move in the epola, sweeping their constituent nuclei and electrons between epola particles, creating EM de Broglie waves in the epola space, but no winds or currents. Starting a motion provides the energy of the bound epola particles that vibrate in the waves. This led us to answer the question WHY there is inertia. Epola deformations by masses of constituent nuclear particles of atomic bodies led us to answer the question WHY there is gravity. Epola deformations by electric charges and magnetism of the particles lead to answer the questions of HOW and WHY does space carry and transfer with the speed c of light the tremendous gravitational and EM interaction forces, energies, and radiations. The lattice structure per se causes all quantizations, and the applicability of the otherwise "divine" principles of uncertainty, exclusion, particle-wave duality, universality of our backyard findings, etc. 1.M.Simhony, The Epola Space, 1990, 160 pp, and The Story of Matter and Space, 1999, 70 pp (available from the author). M.Simhony, Invitation to the Natural Physics or Matter, Space, and Radiation, World Scientific, 1994. See the website: http://come.to/natural_physics

  10. Studying Dynamic Features in Myocardial Infarction Progression by Integrating miRNA-Transcription Factor Co-Regulatory Networks and Time-Series RNA Expression Data from Peripheral Blood Mononuclear Cells.

    PubMed

    Shi, Hongbo; Zhang, Guangde; Wang, Jing; Wang, Zhenzhen; Liu, Xiaoxia; Cheng, Liang; Li, Weimin

    2016-01-01

    Myocardial infarction (MI) is a serious heart disease and a leading cause of mortality and morbidity worldwide. Although some molecules (genes, miRNAs and transcription factors (TFs)) associated with MI have been studied in a specific pathological context, their dynamic characteristics in gene expressions, biological functions and regulatory interactions in MI progression have not been fully elucidated to date. In the current study, we analyzed time-series RNA expression data from peripheral blood mononuclear cells. We observed that significantly differentially expressed genes were sharply up- or down-regulated in the acute phase of MI, and then changed slowly until the chronic phase. Biological functions involved at each stage of MI were identified. Additionally, dynamic miRNA-TF co-regulatory networks were constructed based on the significantly differentially expressed genes and miRNA-TF co-regulatory motifs, and the dynamic interplay of miRNAs, TFs and target genes were investigated. Finally, a new panel of candidate diagnostic biomarkers (STAT3 and ICAM1) was identified to have discriminatory capability for patients with or without MI, especially the patients with or without recurrent events. The results of the present study not only shed new light on the understanding underlying regulatory mechanisms involved in MI progression, but also contribute to the discovery of true diagnostic biomarkers for MI. PMID:27367417

  11. Studying Dynamic Features in Myocardial Infarction Progression by Integrating miRNA-Transcription Factor Co-Regulatory Networks and Time-Series RNA Expression Data from Peripheral Blood Mononuclear Cells

    PubMed Central

    Wang, Jing; Wang, Zhenzhen; Liu, Xiaoxia; Cheng, Liang; Li, Weimin

    2016-01-01

    Myocardial infarction (MI) is a serious heart disease and a leading cause of mortality and morbidity worldwide. Although some molecules (genes, miRNAs and transcription factors (TFs)) associated with MI have been studied in a specific pathological context, their dynamic characteristics in gene expressions, biological functions and regulatory interactions in MI progression have not been fully elucidated to date. In the current study, we analyzed time-series RNA expression data from peripheral blood mononuclear cells. We observed that significantly differentially expressed genes were sharply up- or down-regulated in the acute phase of MI, and then changed slowly until the chronic phase. Biological functions involved at each stage of MI were identified. Additionally, dynamic miRNA–TF co-regulatory networks were constructed based on the significantly differentially expressed genes and miRNA–TF co-regulatory motifs, and the dynamic interplay of miRNAs, TFs and target genes were investigated. Finally, a new panel of candidate diagnostic biomarkers (STAT3 and ICAM1) was identified to have discriminatory capability for patients with or without MI, especially the patients with or without recurrent events. The results of the present study not only shed new light on the understanding underlying regulatory mechanisms involved in MI progression, but also contribute to the discovery of true diagnostic biomarkers for MI. PMID:27367417

  12. Microbial dynamics during shelf-life of industrial Ricotta cheese and identification of a Bacillus strain as a cause of a pink discolouration.

    PubMed

    Sattin, E; Andreani, N A; Carraro, L; Fasolato, L; Balzan, S; Novelli, E; Squartini, A; Telatin, A; Simionati, B; Cardazzo, B

    2016-08-01

    Dairy products are perishable and have to be preserved from spoilage during the food chain to achieve the desired shelf-life. Ricotta is a typical Italian soft dairy food produced by heat coagulation of whey proteins and is considered to be a light and healthy product. The shelf-life of Ricotta could be extended, as required by the international food trade market; however, heat resistant microflora causes spoilage and poses issues regarding the safety of the product. Next-generation sequencing (NGS) applied to the Ricotta samples defined the composition of the microbial community in-depth during the shelf-life. The analysis demonstrated the predominance of spore-forming bacteria throughout the shelf-life, mostly belonging to Bacillus, Paenibacillus and Clostridium genera. A strain involved in spoilage and causing a pink discolouration of Ricotta was isolated and characterised as Bacillus mycoides/weihenstephanensis. This is the first report of a food discolouration caused by a toxigenic strain belonging to the Bacillus cereus group that resulted the predominant strain in the community of the defective ricotta. These results suggest that the processing of raw materials to eliminate spores and residual microflora could be essential for improving the quality and the safety of the product and to extend the shelf-life of industrial Ricotta. PMID:27052696

  13. Population dynamics of sea ducks: using models to understand the causes, consequences, evolution, and management of variation in life history characteristics

    USGS Publications Warehouse

    Flint, Paul L.

    2015-01-01

    In this chapter, I explore population dynamics of sea ducks by developing population models. In determining which life history characteristics had the greatest influence on future population dynamics, adult female survival consistently had the highest sensitivity and elasticity and this result was robust across a wide range of life history parameter values. Conversely, retrospective models consistently found that the majority of annual variation in lambda was associate with variation in productivity. Stochastic models that are base on process variation and incorporate correlations among life history parameters are the most useful for visualizing the probability of achieving a desired management outcome. Effective management targets both the mean and the variance parameters and takes advantage of correlations among life history parameters. Example models demonstrate that sea duck species can achieve equal fitness using a variety of survival and productivity combinations. Sea duck populations will tend to have long time largest in terms of responding to management actions. Understanding the role of density-dependent population regulation is critical for effective sea duck management and conservation.

  14. Hydrogen-bond-dynamics-based switching of conductivity and magnetism: a phase transition caused by deuterium and electron transfer in a hydrogen-bonded purely organic conductor crystal.

    PubMed

    Ueda, Akira; Yamada, Shota; Isono, Takayuki; Kamo, Hiromichi; Nakao, Akiko; Kumai, Reiji; Nakao, Hironori; Murakami, Youichi; Yamamoto, Kaoru; Nishio, Yutaka; Mori, Hatsumi

    2014-08-27

    A hydrogen bond (H-bond) is one of the most fundamental and important noncovalent interactions in chemistry, biology, physics, and all other molecular sciences. Especially, the dynamics of a proton or a hydrogen atom in the H-bond has attracted increasing attention, because it plays a crucial role in (bio)chemical reactions and some physical properties, such as dielectricity and proton conductivity. Here we report unprecedented H-bond-dynamics-based switching of electrical conductivity and magnetism in a H-bonded purely organic conductor crystal, κ-D3(Cat-EDT-TTF)2 (abbreviated as κ-D). This novel crystal κ-D, a deuterated analogue of κ-H3(Cat-EDT-TTF)2 (abbreviated as κ-H), is composed only of a H-bonded molecular unit, in which two crystallographically equivalent catechol-fused ethylenedithiotetrathiafulvalene (Cat-EDT-TTF) skeletons with a +0.5 charge are linked by a symmetric anionic [O···D···O](-1)-type strong H-bond. Although the deuterated and parent hydrogen systems, κ-D and κ-H, are isostructural paramagnetic semiconductors with a dimer-Mott-type electronic structure at room temperature (space group: C2/c), only κ-D undergoes a phase transition at 185 K, to change to a nonmagnetic insulator with a charge-ordered electronic structure (space group: P1). The X-ray crystal structure analysis demonstrates that this dramatic switching of the electronic structure and physical properties originates from deuterium transfer or displacement within the H-bond accompanied by electron transfer between the Cat-EDT-TTF π-systems, proving that the H-bonded deuterium dynamics and the conducting TTF π-electron are cooperatively coupled. Furthermore, the reason why this unique phase transition occurs only in κ-D is qualitatively discussed in terms of the H/D isotope effect on the H-bond geometry and potential energy curve. PMID:25127315

  15. Differences in intracellular calcium dynamics cause differences in α-granule secretion and phosphatidylserine expression in platelets adhering on glass and TiO2.

    PubMed

    Gupta, Swati; Donati, Alessia; Reviakine, Ilya

    2016-06-01

    In this study, the activation of purified human platelets due to their adhesion on glass and TiO2 in the absence of extracellular calcium was investigated. Differences in α-granule secretion between platelets adhering on the two surfaces were detected by examining the expression and secretion of the α-granule markers P-selectin (CD62P) and β-thromboglobulin. Similarly, differences in the expression of phosphatidylserine (PS), and in the activation of the major integrin GPIIb/IIIa, on the surfaces of the adhering platelets, were also observed. While all of these activation markers were expressed in platelets adhering on glass, the surface markers were not expressed in platelets adhering on TiO2, and β-thromboglobulin secretion levels were substantially reduced. Differences in marker expression and secretion correlated with differences in the intracellular calcium dynamics. Calcium ionophore treatment triggered α-granule secretion and PS expression in TiO2-adhering platelets but had no effect on the activation of GPIIb/IIIa. These results demonstrate specificity in the way surfaces of artificial materials activate platelets, link differences in the intracellular calcium dynamics observed in the platelets adhering on the two surfaces to the differences in some of the platelet responses (α-granule secretion and PS expression), but also highlight the involvement of synergistic, calcium-independent pathways in platelet activation. The ability to control activation in surface-adhering platelets makes this an attractive model system for studying platelet signaling pathways and for tissue engineering applications. PMID:27124595

  16. Gait recognition based on fusion features

    NASA Astrophysics Data System (ADS)

    Wu, Haizhen; Jiang, Jiafu; Chen, Xi

    2009-10-01

    Gait recognition and analysis is a promising biometrics technology finding applications in numerous sectors of our society. This paper proposes a new fusion algorithm where the static and dynamic features are fused to obtain optimal performance. The new fusion algorithm divides decision situations into two categories. The wavelet moment is used to describe the static features of gait sequence images, and the three widths of the body contour are used to describe the dynamic features. In addition, the Principal Component Analysis (PCA) for feature transformation of spatial templates is proposed. The experimental results demonstrate that the proposed algorithm performs an encouraging recognition rate.

  17. Dynamics of change of lipid and monoamine metabolisms and the blood coagulation system during experimental atherosclerosis caused by restriction of movement

    NASA Technical Reports Server (NTRS)

    Gvishiani, G. S.; Kobakhidze, N. G.

    1980-01-01

    Shifts in lipid, catecholamine, and blood coagulation systems following various periods (1, 2, 3, and 4 months) of experimentally induced atherosclerosis were studied. The same indices were studied in the tissues of the myocardium, liver, and brain stem-reticular formation after decapitation of the animals at the end of the experiment. Periodic motion restriction caused an increase in blood beta-lipoproteins in the rabbits at the beginning of the experiment. An increase in general cholesterol content and a decrease in the lecithincholesterol index were established at the end of the experiment. Myocardial beta-lipoprotein and brain stem reticular formation general cholesterol contents were elevated; catecholamine content was increased at the end of the experiment. In the initial months, free adrenaline basically increased, while in later months blood adrenaline decreased and blood noradrenaline increased.

  18. Rates, causes, and dynamic of long-term landscape evolution of the South Atlantic "passive continental margin", Brazil and Namibia, as revealed by thermo-kinematic numerical modeling.

    NASA Astrophysics Data System (ADS)

    Christian, Stippich; Anton, Glasmacher Ulrich; Peter, Christian, Hackspacher

    2014-05-01

    The aim of the research is to quantify the long-term landscape evolution of the South Atlantic passive continental margin (SAPCM) in SE-Brazil and NW-Namibia. Excellent onshore outcrop conditions and complete rift to post-rift archives between Sao Paulo and Porto Alegre and in the transition from Namibia to Angola (onshore Walvis ridge) allow a high precision quantification of exhumation, and uplift rates, influencing physical parameters, long-term acting forces, and process-response systems. Research will integrate the published and partly published thermochronological data from Brazil and Namibia, and test lately published new concepts on causes of long-term landscape evolution at rifted margins. The climate-continental margin-mantle coupled process-response system is caused by the interaction between endogenous and exogenous forces, which are related to the mantle-process driven rift - drift - passive continental margin evolution of the South Atlantic, and the climate change since the Early/Late Cretaceous climate maximum. Special emphasis will be given to the influence of long-living transform faults such as the Florianopolis Fracture Zone (FFZ) on the long-term topography evolution of the SAPCM's. A long-term landscape evolution model with process rates will be achieved by thermo-kinematic 3-D modeling (software code PECUBE and FastCape). Testing model solutions obtained for a multidimensional parameter space against the real thermochronological and geomorphological data set, the most likely combinations of parameter rates, and values can be constrained. The data and models will allow separating the exogenous and endogenous forces and their process rates.

  19. The sexually driven epidemic in youths in China’s southwestern border region was caused by dynamic emerging multiple recombinant HIV-1 strains

    PubMed Central

    Wei, Huamian; Xing, Hui; Hsi, Jenny H.; Jia, Manhong; Feng, Yi; Duan, Song; He, Cui; Yao, Shitang; Ruan, Yuhua; He, Xiang; Liao, Lingjie; Ma, Yanling; Huang, Yunda; Lu, Lin; Shao, Yiming

    2015-01-01

    Dehong prefecture, Yunnan province on China’s southwestern border was the gateway of the country’s AIDS epidemic. Studies on HIV-1 molecular epidemiology will provide key information on virus transmission dynamics and help to inform HIV prevention strategies. HIV-1 infected youths (age 16–25 years) diagnosed in the continuous 3 months in 2009 to 2012 were enrolled. By means of phylogenetic and statistical analyses, It was showed that two thirds (133/205) of youths in Dehong, of which 74.1% were infected sexually, were infected by uncharacterized recombinant HIV-1 strains. Among them about 59.4% (79/131) were unique recombinant forms (URFs) and 40.6% (54/131) formed 11 transmission clusters, termed potential circulating recombinant forms (pCRFs). The emergence of recombinants was statistically significant related with people of low education, residents outside the capital city of Dehong and being Myanmar residents. It was the first report with ongoing HIV-1 recombinant strains in a sexually driven epidemic area in China. Great efforts should be put on reducing multiple risk exposures behavior in local young people, containing the spread of pCRFs to other regions, and preventing the URFs from evolving into future CRFs. Collaborative prevention across border is needed to better control the local AIDS epidemic. PMID:26133091

  20. Endemicity of chytridiomycosis features pathogen overdispersion.

    PubMed

    Grogan, Laura F; Phillott, Andrea D; Scheele, Benjamin C; Berger, Lee; Cashins, Scott D; Bell, Sara C; Puschendorf, Robert; Skerratt, Lee F

    2016-05-01

    Pathogens can be critical drivers of the abundance and distribution of wild animal populations. The presence of an overdispersed pathogen load distribution between hosts (where few hosts harbour heavy parasite burdens and light infections are common) can have an important stabilizing effect on host-pathogen dynamics where infection intensity determines pathogenicity. This may potentially lead to endemicity of an introduced pathogen rather than extirpation of the host and/or pathogen. Overdispersed pathogen load distributions have rarely been considered in wild animal populations as an important component of the infection dynamics of microparasites such as bacteria, viruses, protozoa and fungi. Here we examined the abundance, distribution and transmission of the model fungal pathogen Batrachochytrium dendrobatidis (Bd, cause of amphibian chytridiomycosis) between wild-caught Litoria rheocola (common mist frogs) to investigate the effects of an overdispersed pathogen load distribution on the host population in the wild. We quantified host survival, infection incidence and recovery probabilities relative to infectious burden, and compared the results of models where pathogen overdispersion either was or was not considered an important feature of host-pathogen dynamics. We found the distribution of Bd load between hosts to be highly overdispersed. We found that host survival was related to infection burden and that accounting for pathogen overdispersion allowed us to better understand infection dynamics and their implications for disease control. In addition, we found that the pattern of host infections and recoveries varied markedly with season whereby (i) infections established more in winter, consistent with temperature-dependent effects on fungal growth, and (ii) recoveries (loss of infection) occurred frequently in the field throughout the year but were less likely in winter. Our results suggest that pathogen overdispersion is an important feature of endemic

  1. A novel microtubule inhibitor, MT3-037, causes cancer cell apoptosis by inducing mitotic arrest and interfering with microtubule dynamics

    PubMed Central

    Chang, Ling-Chu; Yu, Yung-Luen; Hsieh, Min-Tsang; Wang, Sheng-Hung; Chou, Ruey-Hwang; Huang, Wei-Chien; Lin, Hui-Yi; Hung, Hsin-Yi; Huang, Li-Jiau; Kuo, Sheng-Chu

    2016-01-01

    We investigated the anticancer potential of a new synthetic compound, 7-(3-fluorophenyl)-4-methylpyrido-[2,3-d]pyrimidin-5(8H)-one (MT3-037). We found that MT3-037 effectively decreased the cancer cell viability by inducing apoptosis. MT3-037 treatments led to cell cycle arrest at M phase, with a marked increase in both expression of cyclin B1 and cyclin-dependent kinase 1 (CDK1) as well as in CDK1 kinase activity. Key proteins that regulate mitotic spindle dynamics, including survivin, Aurora A/B kinases, and polo-like kinase 1 (PLK1), were activated in MT3-037-treated cells. MT3-037-induced apoptosis was accompanied by activation of a pro-apoptotic factor, FADD, and the inactivation of apoptosis inhibitors, Bcl-2 and Bcl-xL, resulting in the cleavage/activation of caspases. The activation of c-Jun N-terminal kinase (JNK) was associated with MT3-037-induced CDK1 and Aurora A/B activation and apoptosis. Immunofluorescence staining of tubulin indicated that MT3-037 altered tubulin networks in cancer cells. Moreover, an in vitro tubulin polymerization assay revealed that MT3-037 inhibited the tubulin polymerization by direct binding to tubulin. Molecular docking studies and binding site completion assays revealed that MT3-037 binds to the colchicine-binding site. Furthermore, MT3-037 significantly inhibited the tumor growth in both MDAMB-468 and Erlotinib-resistant MDA-MB-468 xenograft mouse models. In addition, MT3-037 inhibited the angiogenesis and disrupted the tube formation by human endothelial cells. Our study demonstrates that MT3-037 is a potential tubulin-disrupting agent for antitumor therapy. PMID:27186428

  2. A novel microtubule inhibitor, MT3-037, causes cancer cell apoptosis by inducing mitotic arrest and interfering with microtubule dynamics.

    PubMed

    Chang, Ling-Chu; Yu, Yung-Luen; Hsieh, Min-Tsang; Wang, Sheng-Hung; Chou, Ruey-Hwang; Huang, Wei-Chien; Lin, Hui-Yi; Hung, Hsin-Yi; Huang, Li-Jiau; Kuo, Sheng-Chu

    2016-01-01

    We investigated the anticancer potential of a new synthetic compound, 7-(3-fluorophenyl)-4-methylpyrido-[2,3-d]pyrimidin-5(8H)-one (MT3-037). We found that MT3-037 effectively decreased the cancer cell viability by inducing apoptosis. MT3-037 treatments led to cell cycle arrest at M phase, with a marked increase in both expression of cyclin B1 and cyclin-dependent kinase 1 (CDK1) as well as in CDK1 kinase activity. Key proteins that regulate mitotic spindle dynamics, including survivin, Aurora A/B kinases, and polo-like kinase 1 (PLK1), were activated in MT3-037-treated cells. MT3-037-induced apoptosis was accompanied by activation of a pro-apoptotic factor, FADD, and the inactivation of apoptosis inhibitors, Bcl-2 and Bcl-xL, resulting in the cleavage/activation of caspases. The activation of c-Jun N-terminal kinase (JNK) was associated with MT3-037-induced CDK1 and Aurora A/B activation and apoptosis. Immunofluorescence staining of tubulin indicated that MT3-037 altered tubulin networks in cancer cells. Moreover, an in vitro tubulin polymerization assay revealed that MT3-037 inhibited the tubulin polymerization by direct binding to tubulin. Molecular docking studies and binding site completion assays revealed that MT3-037 binds to the colchicine-binding site. Furthermore, MT3-037 significantly inhibited the tumor growth in both MDAMB-468 and Erlotinib-resistant MDA-MB-468 xenograft mouse models. In addition, MT3-037 inhibited the angiogenesis and disrupted the tube formation by human endothelial cells. Our study demonstrates that MT3-037 is a potential tubulin-disrupting agent for antitumor therapy. PMID:27186428

  3. Economic inequality caused by feedbacks between poverty and the dynamics of a rare tropical disease: the case of Buruli ulcer in sub-Saharan Africa.

    PubMed

    Garchitorena, Andrés; Ngonghala, Calistus N; Guegan, Jean-Francois; Texier, Gaëtan; Bellanger, Martine; Bonds, Matthew; Roche, Benjamin

    2015-11-01

    Neglected tropical diseases (NTDs) have received increasing attention in recent years by the global heath community, as they cumulatively constitute substantial burdens of disease as well as barriers for economic development. A number of common tropical diseases such as malaria, hookworm or schistosomiasis have well-documented economic impacts. However, much less is known about the population-level impacts of diseases that are rare but associated with high disability burden, which represent a great number of tropical diseases. Using an individual-based model of Buruli ulcer (BU), we demonstrate that, through feedbacks between health and economic status, such NTDs can have a significant impact on the economic structure of human populations even at low incidence levels. While average wealth is only marginally affected by BU, the economic conditions of certain subpopulations are impacted sufficiently to create changes in measurable population-level inequality. A reduction of the disability burden caused by BU can thus maximize the economic growth of the poorest subpopulations and reduce significantly the economic inequalities introduced by the disease in endemic regions. PMID:26538592

  4. Rare causes of osteoporosis

    PubMed Central

    Marcucci, Gemma; Brandi, Maria Luisa

    2015-01-01

    Summary Osteoporosis is a metabolic bone disease characterized by loss of bone mass and strength, resulting in increased risk of fractures. It is classically divided into primary (post-menopausal or senile), secondary and idiopathic forms. There are many rare diseases, that cause directly or indirectly osteoporosis. The identification and classification of most of these rare causes of osteoporosis is crucial for the specialists in endocrinology and not, in order to prevent this bone complication and to provide for an early therapy. Several pathogenic mechanisms are involved, including various aspects of bone metabolism such as: decreased bone formation, increased bone resorption, altered calcium, phosphorus and/or vitamin D homeostasis, and abnormal collagen synthesis. In this review, less common forms of primary and secondary osteoporosis are described, specifying, if applicable: genetic causes, epidemiology, clinical features, and pathogenic mechanisms causing osteoporosis. A greater awareness of all rare causes of osteoporosis could reduce the number of cases classified as idiopathic osteoporosis and allow the introduction of appropriate and timely treatments. PMID:26604941

  5. The Enigmatic Thirteen Micron Feature

    NASA Astrophysics Data System (ADS)

    de Queiroz e Souza, Nelson

    Low and intermediate mass stars (0.8--8 solar masses) will eventually evolve into Asymptotic Giant Branch (AGB) stars and pulsate out their atmosphere into the space around them. That ejected material will eventually cool and form dust. Understanding the nature and formation of cosmic dust is crucial to understanding the Universe. Evolved intermediate mass stars (i.e. AGB stars) are major contributors of dust to the cosmos. Dust around AGB stars are studied by means of infrared spectroscopy from which we observe several interesting spectral features. The observed AGB star spectra have been classified according to their shapes and wavelength positions of the dust features. Alongside the main spectral features around 8-12mum, there is an enigmatic 13mum feature that appears in about half the oxygen-rich AGB stars. The carrier of this feature has not yet been unequivocally identified but has been attributed to various dust species, including corundum (crystalline Al2O3), spinel (MgAl2O4), and silica (SiO2). While there have been several attempts to determine the cause of this 13mum feature, previous studies have been somewhat contradictory. In order to investigate the origin and characteristics of this spectral feature we observe variations in the 13mum feature over varying stellar parameters. We have also acquired spatially resolved spectroscopic observations of nearby O-rich AGB stars using Michelle on Gemini North. Here we present data on the 13mum feature strength mapped over space around their respective AGB star. The most popular hypothesis for the carrier of the 13mm feature is not supported by our findings.

  6. Observation and prediction of dynamic ground strains, tilts, and torsions caused by the Mw 6.0 2004 Parkfield, California, earthquake and aftershocks, derived from UPSAR array observations

    USGS Publications Warehouse

    Spudich, P.; Fletcher, Joe B.

    2008-01-01

    The 28 September 2004 Parkfield, California, earthquake (Mw 6.0) and four aftershocks (Mw 4.7-5.1) were recorded on 12 accelerograph stations of the U.S. Geological Survey Parkfield seismic array (UPSAR), an array of three-component accelerographs occupying an area of about 1 km2 located 8.8 km from the San Andreas fault. Peak horizontal acceleration and velocity at UPSAR during the mainshock were 0.45g and 27 cm/sec, respectively. We determined both time-varying and peak values of ground dilatations, shear strains, torsions, tilts, torsion rates, and tilt rates by applying a time-dependent geodetic analysis to the observed array displacement time series. Array-derived dilatations agree fairly well with point measurements made on high sample rate recordings of the Parkfield-area dilatometers (Johnston et al., 2006). Torsion Fourier amplitude spectra agree well with ground velocity spectra, as expected for propagating plane waves. A simple predictive relation, using the predicted peak velocity from the Boore-Atkinson ground-motion prediction relation (Boore and Atkinson, 2007) scaled by a phase velocity of 1 km/sec, predicts observed peak Parkfield and Chi-Chi rotations (Huang, 2003) well. However, rotation rates measured during Mw 5 Ito, Japan, events observed on a gyro sensor (Takeo, 1998) are factors of 5-60 greater than those predicted by our predictive relation. This discrepancy might be caused by a scale dependence in rotation, with rotations measured over a short baseline exceeding those measured over long baselines. An alternative hypothesis is that events having significant non-double-couple mechanisms, like the Ito events, radiate much stronger rotations than double-couple events. If this is true, then rotational observations might provide an important source of new information for monitoring seismicity in volcanic areas.

  7. Observation and Prediction of Dynamic Ground Strains, Tilts and Torsions Caused by the M6.0 2004 Parkfield, California, Earthquake and Aftershocks Derived From UPSAR Array Observations

    NASA Astrophysics Data System (ADS)

    Spudich, P.; Fletcher, J. B.

    2008-12-01

    The September 28, 2004, Parkfield, California, earthquake (Mw 6.0) and four aftershocks (Mw 4.7 - 5.1) were recorded on 12 accelerograph stations of the UPSAR seismic array, an array of three-component accelerographs occupying an area of about 1 square km located 8.8 km from the San Andreas fault. Peak horizontal acceleration and velocity at UPSAR during the mainshock were 0.45 g and 0.27 m/s, respectively. We determined both time-varying and peak values of ground dilatations, shear strains, torsions, tilts, torsion rates, and tilt rates by applying a time-dependent geodetic analysis to the observed array displacement time series. Array-derived dilatations agree fairly well with point measurements made on high sample rate recordings of the Parkfield-area dilatometers (Johnston et al., 2006). Torsion Fourier amplitude spectra agree well with ground velocity spectra, as expected for propagating plane waves. A simple predictive relation, using predicted peak velocity from the Boore-Atkinson (2007) ground motion prediction relation scaled by a phase velocity of 1 km/s, predicts observed peak Parkfield and Chi-Chi rotations (Huang, 2003) well. However, rotation rates measured during Mw 5 Ito, Japan, events observed on a gyro sensor (Takeo, 1998) are factors of 5 - 60 greater than predicted by our predictive relation. This discrepancy might be caused by a scale-dependence in rotation, with rotations measured over a short baseline exceeding those measured over long baselines. An alternative hypothesis is that events having significant non-double-couple mechanisms, like the Ito events, radiate much stronger rotations than double-couple events. If this is true, then rotational observations might provide an important source of new information for monitoring seismicity in volcanic areas.

  8. Fourth-Generation Epac-Based FRET Sensors for cAMP Feature Exceptional Brightness, Photostability and Dynamic Range: Characterization of Dedicated Sensors for FLIM, for Ratiometry and with High Affinity

    PubMed Central

    Klarenbeek, Jeffrey; Goedhart, Joachim; van Batenburg, Aernoud; Groenewald, Daniella; Jalink, Kees

    2015-01-01

    Epac-based FRET sensors have been widely used for the detection of cAMP concentrations in living cells. Originally developed by us as well as others, we have since then reported several important optimizations that make these sensors favourite among many cell biologists. We here report cloning and characterization of our fourth generation of cAMP sensors, which feature outstanding photostability, dynamic range and signal-to-noise ratio. The design is based on mTurquoise2, currently the brightest and most bleaching-resistant donor, and a new acceptor cassette that consists of a tandem of two cp173Venus fluorophores. We also report variants with a single point mutation, Q270E, in the Epac moiety, which decreases the dissociation constant of cAMP from 9.5 to 4 μM, and thus increases the affinity ~ 2.5-fold. Finally, we also prepared and characterized dedicated variants with non-emitting (dark) acceptors for single-wavelength FLIM acquisition that display an exceptional near-doubling of fluorescence lifetime upon saturation of cAMP levels. We believe this generation of cAMP outperforms all other sensors and therefore recommend these sensors for all future studies. PMID:25875503

  9. Multivariate Feature Selection for Predicting Scour-Related Bridge Damage using a Genetic Algorithm

    NASA Astrophysics Data System (ADS)

    Anderson, I.

    2015-12-01

    Scour and hydraulic damage are the most common cause of bridge failure, reported to be responsible for over 60% of bridge failure nationwide. Scour is a complex process, and is likely an epistatic function of both bridge and stream conditions that are both stationary and in dynamic flux. Bridge inspections, conducted regularly on bridges nationwide, rate bridge health assuming a static stream condition, and typically do not include dynamically changing geomorphological adjustments. The Vermont Agency of Natural Resources stream geomorphic assessment data could add value into the current bridge inspection and scour design. The 2011 bridge damage from Tropical Storm Irene served as a case study for feature selection to improve bridge scour damage prediction in extreme events. The bridge inspection (with over 200 features on more than 300 damaged and 2,000 non-damaged bridges), and the stream geomorphic assessment (with over 300 features on more than 5000 stream reaches) constitute "Big Data", and together have the potential to generate large numbers of combined features ("epistatic relationships") that might better predict scour-related bridge damage. The potential combined features pose significant computational challenges for traditional statistical techniques (e.g., multivariate logistic regression). This study uses a genetic algorithm to perform a search of the multivariate feature space to identify epistatic relationships that are indicative of bridge scour damage. The combined features identified could be used to improve bridge scour design, and to better monitor and rate bridge scour vulnerability.

  10. High resolution cloud feature tracking on Venus by Galileo

    NASA Technical Reports Server (NTRS)

    Toigo, Anthony; Gierasch, Peter J.; Smith, Michael D.

    1994-01-01

    The Venus cloud deck was monitored in February 1990 for 16 hours at 400 nanometers wavelength by the Galileo imaging system, with a spatial resolution of about 15 km and with image time separations as small as 10 minutes. Velocities are deduced by following the motion of small cloud features. In spite of the high temporal frequence is capable of being detected, no dynamical phenomena are apparent in the velocity data except the already well-known solar tides, possibly altered by the slow 4-day wave and the Hadley circulation. There is no evidence, to a level of approximately 4 m/s, of eddy or wavelike activity. The dominant size of sub-global scale albedo features is 200-500 km, and their contrast is approximately 5%. At low altitudes there are patches of blotchy, cell-like structures but at most locations the markings are streaky. The patterns are similar to those discovered by Mariner 10 and Pioneer Venus (M. J. S. Belton et al., 1976, W. B. Rossow et al., 1980). Scaling arguments are presented to argue that the mesoscale blotchy cell-like cloud patterns are caused by local dynamics driven in a shallow layer by differential absorption of sunlight. It is also argued that mesoscale albedo features are either streaky or cell-like simply depending on whether the horizontal shear of the large scale flow exceeds a certain critical value.

  11. Dynamic Geometry on WWW.

    ERIC Educational Resources Information Center

    Kuntz, Gilles

    The first section of this paper on World Wide Web applications related to dynamic geometry addresses dynamic geometry and teaching, including the relationship between dynamic geometry and direct manipulation, key features of dynamic geometry environments, the importance of direct engagement of the learner using construction software for…

  12. Collaborative Writing Features

    ERIC Educational Resources Information Center

    Yong Mei Fung

    2010-01-01

    As part of a research study on collaborative writing, this paper discusses defining and facilitating features that occur during face-to-face collaboration, based on the literature and research. The defining features are mutual interaction, negotiations, conflict, and shared expertise. Facilitating features include affective factors, use of L1,…

  13. Molecular dynamics simulation and free energy landscape methods in probing L215H, L217R and L225M βI-tubulin mutations causing paclitaxel resistance in cancer cells.

    PubMed

    Tripathi, Shubhandra; Srivastava, Gaurava; Sharma, Ashok

    2016-08-01

    Drug resistance poses a threatening challenge for mankind, as the development of resistance to already well-established drugs causes serious therapeutic problems. Resistance to paclitaxel (Ptxl), a complex diterpenoid working as microtubule stabilizer, is one such issue in cancer treatment. Microtubule stabilizer drugs, stabilises microtubules upon binding to β-tubulin subunit of tubulin heterodimer thus causing mitotic arrest leading to death of cancer cell. Leucine point mutations viz. L215H, L217R, and L225M were reported for Ptxl resistance in various cancers. In the current study, molecular mechanism of these resistance causing mutations was explored using molecular docking, molecular dynamics (MD) simulation, binding energy estimation (MMPBSA), free energy decomposition, principle component analysis (PCA) and free energy landscape (FEL) methods. A total of five systems including unbound βI-tubulin (Apo), docked wild+Ptxl, L215H+Ptxl, L217R+Ptxl and L225M+Ptxl were prepared, and 50 ns MD simulation was performed for each system. Binding energy estimation indicated that leucine mutation reduces the binding affinity of Ptxl in mutant types (MTs) as compared to wild type (WT). Further, in contrast to WT Ptxl interactions with the M-loop (PHE270-VAL286), S6-S7 loop and H9-H10 were significantly altered in MTs. Results showed that in MTs, Ptxl had weak interaction with M-loop residues, while having strong affinity with S6-S7 loop and H6-H7 loop. Moreover, PCA and FEL analysis revealed that M-loop flexible region (THR274-LEU284) was strongly bound with Ptxl in WT preventing its flexible movement and the causing factor for microtubule stabilization. In MTs due to poor interaction with Ptxl, M-loop flexible region retains its flexibility, therefore unable to stabilize microtubule. This study will give an insight into the importance of M-loop flexible region interaction with Ptxl for microtubule stabilization. In addition, it clearly provides the molecular basis of

  14. Adaptive feature extraction expert

    SciTech Connect

    Yuschik, M.

    1983-01-01

    The identification of discriminatory features places an upper bound on the recognition rate of any automatic speech recognition (ASR) system. One way to structure the extraction of features is to construct an expert system which applies a set of rules to identify particular properties of the speech patterns. However, these patterns vary for an individual speaker and from speaker to speaker so that another expert is actually needed to learn the new variations. The author investigates the problem by using sets of discriminatory features that are suggested by a feature generation expert, improves the selectivity of these features with a training expert, and finally develops a minimally spanning feature set with a statistical selection expert. 12 references.

  15. Persuasion dynamics

    NASA Astrophysics Data System (ADS)

    Weisbuch, Gérard; Deffuant, Guillaume; Amblard, Frédéric

    2005-08-01

    We here discuss a model of continuous opinion dynamics in which agents adjust continuous opinions as a result of random binary encounters whenever their difference in opinion is below a given threshold. We concentrate on the version of the model in the presence of few extremists which might drive the dynamics to generalized extremism. A network version of the dynamics is presented here, and its results are compared to those previously obtained for the full-mixing case. The same dynamical regimes are observed, but in rather different parameter regions. We here show that the combination of meso-scale features resulting from the first interaction steps determines the asymptotic state of the dynamics.

  16. Understanding Rheumatoid Arthritis (RA): Treatment and Causes

    MedlinePlus

    ... this page please turn JavaScript on. Feature: Understanding Rheumatoid Arthritis (RA) Treatment and Causes Past Issues / Summer 2014 Table of Contents How Is Rheumatoid Arthritis Treated? Doctors have many ways to treat this ...

  17. Dynamics Resonances in Atomic States of Astrophysical Relevance

    NASA Astrophysics Data System (ADS)

    Arefieff, K. N.; Miculis, K.; Bezuglov, N. N.; Dimitrijević, M. S.; Klyucharev, A. N.; Mihajlov, A. A.; Srećković, V. A.

    2015-12-01

    Ionized geocosmic media parameters in a thermal and a subthermal range of energy have a number of unique features. The photoresonance plasma that is formed by optical excitation of the lowest excited (resonance) atomic states is one example of conversion of radiation energy into electrical one. Since spontaneous fluorescence of excited atoms is probabilistic, the description of the radiating quantized system evolution along with photon energy transfer in a cold atom medium, should include elements of stochastic dynamics. Finally, the chaotic dynamics of a weakly bound Rydberg electron over a grid of the energy level diagram of a quasi-molecular Rydberg complex provides an excitation migration of the electron forward to the ionization continuum. This work aims at discussing the specific features of the dynamic resonances formalism in the description of processes involving Rydberg states of an excited atom, including features in the fluorescence spectrum partially caused by the quantum defect control due to the presence of statistic electromagnetic fields.

  18. JCE Feature Columns

    NASA Astrophysics Data System (ADS)

    Holmes, Jon L.

    1999-05-01

    The Features area of JCE Online is now readily accessible through a single click from our home page. In the Features area each column is linked to its own home page. These column home pages also have links to them from the online Journal Table of Contents pages or from any article published as part of that feature column. Using these links you can easily find abstracts of additional articles that are related by topic. Of course, JCE Online+ subscribers are then just one click away from the entire article. Finding related articles is easy because each feature column "site" contains links to the online abstracts of all the articles that have appeared in the column. In addition, you can find the mission statement for the column and the email link to the column editor that I mentioned above. At the discretion of its editor, a feature column site may contain additional resources. As an example, the Chemical Information Instructor column edited by Arleen Somerville will have a periodically updated bibliography of resources for teaching and using chemical information. Due to the increase in the number of these resources available on the WWW, it only makes sense to publish this information online so that you can get to these resources with a simple click of the mouse. We expect that there will soon be additional information and resources at several other feature column sites. Following in the footsteps of the Chemical Information Instructor, up-to-date bibliographies and links to related online resources can be made available. We hope to extend the online component of our feature columns with moderated online discussion forums. If you have a suggestion for an online resource you would like to see included, let the feature editor or JCE Online (jceonline@chem.wisc.edu) know about it. JCE Internet Features JCE Internet also has several feature columns: Chemical Education Resource Shelf, Conceptual Questions and Challenge Problems, Equipment Buyers Guide, Hal's Picks, Mathcad

  19. Occupational asthma caused by ethanolamines.

    PubMed

    Savonius, B; Keskinen, H; Tuppurainen, M; Kanerva, L

    1994-12-01

    Amino alcohols are used in various industries, often as minor constituents of compounds to modify the properties of the compound. Generally, they are considered to be safe, but they have been known to cause local skin irritation at higher concentrations in solutions. We report on three cases of occupational asthma caused by ethanolamines: two metal workers exposed to a cutting fluid containing triethanolamine, and one cleaner exposed to a detergent containing monoethanolamine. The diagnosis was based on work-related symptoms and on a chamber challenge with the suspected agent. Persistence of the symptoms after exposure ended was a common feature of the three cases. PMID:7709998

  20. Multitask joint spatial pyramid matching using sparse representation with dynamic coefficients for object recognition

    NASA Astrophysics Data System (ADS)

    Hajigholam, Mohammad-Hossein; Raie, Abolghasem-Asadollah; Faez, Karim

    2016-03-01

    Object recognition is considered a necessary part in many computer vision applications. Recently, sparse coding methods, based on representing a sparse feature from an image, show remarkable results on several object recognition benchmarks, but the precision obtained by these methods is not yet sufficient. Such a problem arises where there are few training images available. As such, using multiple features and multitask dictionaries appears to be crucial to achieving better results. We use multitask joint sparse representation, using dynamic coefficients to connect these sparse features. In other words, we calculate the importance of each feature for each class separately. This causes the features to be used efficiently and appropriately for each class. Thus, we use variance of features and particle swarm optimization algorithms to obtain these dynamic coefficients. Experimental results of our work on Caltech-101 and Caltech-256 databases show more accuracy compared with state-of-the art ones on the same databases.

  1. New features in MEDM.

    SciTech Connect

    Evans, K., Jr.

    1999-04-13

    MEDM, which is derived from Motif Editor and Display Manager, is the primary graphical interface to the EPICS control system. This paper describes new features that have been added to MEDM in the last two years. These features include new editing capabilities, a PV Info dialog box, a means of specifying limits and precision, a new implementation of the Cartesian Plot, new features for several objects, new capability for the Related Display, help, a user-configurable Execute Menu, reconfigured start-up options, and availability for Windows 95/98/NT. Over one hundred bugs have been fixed, and the program is quite stable and in extensive use.

  2. Resolving the paradox for protein aggregation diseases: NMR structure and dynamics of the membrane-embedded P56S-MSP causing ALS imply a common mechanism for aggregation-prone proteins to attack membranes

    PubMed Central

    Gupta, Garvita; Song, Jianxing

    2014-01-01

    Paradoxically, aggregation of specific proteins is characteristic of many human diseases and aging, yet aggregates have increasingly been found to be unnecessary for initiating pathogenesis. Here we determined the NMR topology and dynamics of a helical mutant in a membrane environment transformed from the 125-residue cytosolic all-β MSP domain of vesicle-associated membrane protein-associated protein B (VAPB) by the ALS-causing P56S mutation. Despite its low hydrophobicity, the P56S major sperm protein (MSP) domain becomes largely embedded in the membrane environment with high backbone rigidity. Furthermore it is composed of five helices with amphiphilicity comparable to those of the partly-soluble membrane toxin mellitin and α-synuclein causing Parkinson's disease. Consequently, the mechanism underlying this chameleon transformation becomes clear: by disrupting the specific tertiary interaction network stabilizing the native all-β MSP fold to release previously-locked amphiphilic segments, the P56S mutation acts to convert the classic MSP fold into a membrane-active protein that is fundamentally indistinguishable from mellitin and α-synuclein which are disordered in aqueous solution but spontaneously partition into membrane interfaces driven by hydrogen-bond energetics gained from forming α-helix in the membrane environments. As segments with high amphiphilicity exist in all proteins, our study successfully resolves the paradox by deciphering that the proteins with a higher tendency to aggregate have a stronger potential to partition into membranes through the same mechanism as α-synuclein to initially attack membranes to trigger pathogenesis without needing aggregates. This might represent the common first step for various kinds of aggregated proteins to trigger familiar, sporadic and aging diseases. Therefore the homeostasis of aggregated proteins in vivo is the central factor responsible for a variety of human diseases including aging. The number and

  3. Modelling the mechanoreceptor's dynamic behaviour.

    PubMed

    Song, Zhuoyi; Banks, Robert W; Bewick, Guy S

    2015-08-01

    All sensory receptors adapt, i.e. they constantly adjust their sensitivity to external stimuli to match the current demands of the natural environment. Electrophysiological responses of sensory receptors from widely different modalities seem to exhibit common features related to adaptation, and these features can be used to examine the underlying sensory transduction mechanisms. Among the principal senses, mechanosensation remains the least understood at the cellular level. To gain greater insights into mechanosensory signalling, we investigated if mechanosensation displayed adaptive dynamics that could be explained by similar biophysical mechanisms in other sensory modalities. To do this, we adapted a fly photoreceptor model to describe the primary transduction process for a stretch-sensitive mechanoreceptor, taking into account the viscoelastic properties of the accessory muscle fibres and the biophysical properties of known mechanosensitive channels (MSCs). The model's output is in remarkable agreement with the electrical properties of a primary ending in an isolated decapsulated spindle; ramp-and-hold stretch evokes a characteristic pattern of potential change, consisting of a large dynamic depolarization during the ramp phase and a smaller static depolarization during the hold phase. The initial dynamic component is likely to be caused by a combination of the mechanical properties of the muscle fibres and a refractory state in the MSCs. Consistent with the literature, the current model predicts that the dynamic component is due to a rapid stress increase during the ramp. More novel predictions from the model are the mechanisms to explain the initial peak in the dynamic component. At the onset of the ramp, all MSCs are sensitive to external stimuli, but as they become refractory (inactivated), fewer MSCs are able to respond to the continuous stretch, causing a sharp decrease after the peak response. The same mechanism could contribute a faster component in the

  4. Exploring strategies for classification of external stimuli using statistical features of the plant electrical response

    PubMed Central

    Chatterjee, Shre Kumar; Das, Saptarshi; Maharatna, Koushik; Masi, Elisa; Santopolo, Luisa; Mancuso, Stefano; Vitaletti, Andrea

    2015-01-01

    Plants sense their environment by producing electrical signals which in essence represent changes in underlying physiological processes. These electrical signals, when monitored, show both stochastic and deterministic dynamics. In this paper, we compute 11 statistical features from the raw non-stationary plant electrical signal time series to classify the stimulus applied (causing the electrical signal). By using different discriminant analysis-based classification techniques, we successfully establish that there is enough information in the raw electrical signal to classify the stimuli. In the process, we also propose two standard features which consistently give good classification results for three types of stimuli—sodium chloride (NaCl), sulfuric acid (H2SO4) and ozone (O3). This may facilitate reduction in the complexity involved in computing all the features for online classification of similar external stimuli in future. PMID:25631569

  5. Robust Tracking Using Particle Filter with a Hybrid Feature

    NASA Astrophysics Data System (ADS)

    Zhao, Xinyue; Satoh, Yutaka; Takauji, Hidenori; Kaneko, Shun'ichi

    This paper presents a novel method for robust object tracking in video sequences using a hybrid feature-based observation model in a particle filtering framework. An ideal observation model should have both high ability to accurately distinguish objects from the background and high reliability to identify the detected objects. Traditional features are better at solving the former problem but weak in solving the latter one. To overcome that, we adopt a robust and dynamic feature called Grayscale Arranging Pairs (GAP), which has high discriminative ability even under conditions of severe illumination variation and dynamic background elements. Together with the GAP feature, we also adopt the color histogram feature in order to take advantage of traditional features in resolving the first problem. At the same time, an efficient and simple integration method is used to combine the GAP feature with color information. Comparative experiments demonstrate that object tracking with our integrated features performs well even when objects go across complex backgrounds.

  6. Automated Extraction of Flow Features

    NASA Technical Reports Server (NTRS)

    Dorney, Suzanne (Technical Monitor); Haimes, Robert

    2005-01-01

    Computational Fluid Dynamics (CFD) simulations are routinely performed as part of the design process of most fluid handling devices. In order to efficiently and effectively use the results of a CFD simulation, visualization tools are often used. These tools are used in all stages of the CFD simulation including pre-processing, interim-processing, and post-processing, to interpret the results. Each of these stages requires visualization tools that allow one to examine the geometry of the device, as well as the partial or final results of the simulation. An engineer will typically generate a series of contour and vector plots to better understand the physics of how the fluid is interacting with the physical device. Of particular interest are detecting features such as shocks, re-circulation zones, and vortices (which will highlight areas of stress and loss). As the demand for CFD analyses continues to increase the need for automated feature extraction capabilities has become vital. In the past, feature extraction and identification were interesting concepts, but not required in understanding the physics of a steady flow field. This is because the results of the more traditional tools like; isc-surface, cuts and streamlines, were more interactive and easily abstracted so they could be represented to the investigator. These tools worked and properly conveyed the collected information at the expense of a great deal of interaction. For unsteady flow-fields, the investigator does not have the luxury of spending time scanning only one "snapshot" of the simulation. Automated assistance is required in pointing out areas of potential interest contained within the flow. This must not require a heavy compute burden (the visualization should not significantly slow down the solution procedure for co-processing environments). Methods must be developed to abstract the feature of interest and display it in a manner that physically makes sense.

  7. Automated Extraction of Flow Features

    NASA Technical Reports Server (NTRS)

    Dorney, Suzanne (Technical Monitor); Haimes, Robert

    2004-01-01

    Computational Fluid Dynamics (CFD) simulations are routinely performed as part of the design process of most fluid handling devices. In order to efficiently and effectively use the results of a CFD simulation, visualization tools are often used. These tools are used in all stages of the CFD simulation including pre-processing, interim-processing, and post-processing, to interpret the results. Each of these stages requires visualization tools that allow one to examine the geometry of the device, as well as the partial or final results of the simulation. An engineer will typically generate a series of contour and vector plots to better understand the physics of how the fluid is interacting with the physical device. Of particular interest are detecting features such as shocks, recirculation zones, and vortices (which will highlight areas of stress and loss). As the demand for CFD analyses continues to increase the need for automated feature extraction capabilities has become vital. In the past, feature extraction and identification were interesting concepts, but not required in understanding the physics of a steady flow field. This is because the results of the more traditional tools like; iso-surface, cuts and streamlines, were more interactive and easily abstracted so they could be represented to the investigator. These tools worked and properly conveyed the collected information at the expense of a great deal of interaction. For unsteady flow-fields, the investigator does not have the luxury of spending time scanning only one "snapshot" of the simulation. Automated assistance is required in pointing out areas of potential interest contained within the flow. This must not require a heavy compute burden (the visualization should not significantly slow down the solution procedure for (co-processing environments). Methods must be developed to abstract the feature of interest and display it in a manner that physically makes sense.

  8. Volcanic features of Io

    USGS Publications Warehouse

    Carr, M.H.; Masursky, H.; Strom, R.G.; Terrile, R.J.

    1979-01-01

    Volcanic activity is apparently higher on Io than on any other body in the Solar System. Its volcanic landforms can be compared with features on Earth to indicate the type of volcanism present on Io. ?? 1979 Nature Publishing Group.

  9. Features in Saturn's rings

    NASA Technical Reports Server (NTRS)

    Esposito, Larry W.; Harris, Craig C.; Simmons, Karen E.

    1987-01-01

    A systematic, uniform search of Voyage 2 photopolarimeter system (PSS) data set for all significant features of Saturn's rings is described. On August 25, 1981, the PSS observed the occultation of the star Delta Scorpii by the rings of Saturn, and the timing of the data taking was rapid enough that the spatial resolution in the radial direction in the ring plane was better than 100 m. Tabular information and figures for 216 significant features that were found are presented.

  10. Feature Characterization Library

    Energy Science and Technology Software Center (ESTSC)

    2006-08-03

    FCLib is a data analysis toolkit constructed to meet the needs of data discovery in large-scale, spatio-temporal data such as finite element simulation data. FCLib is a C library toolkit of building blocks that can be assembled into complex analyses. Important features of FCLib include the following: (1) Support of feature-based analysis, (2) minimization of low-oevel processing, (3) ease of use, and (4) applicable to the wide variety of science domains.

  11. Feature selection for splice site prediction: A new method using EDA-based feature ranking

    PubMed Central

    Saeys, Yvan; Degroeve, Sven; Aeyels, Dirk; Rouzé, Pierre; Van de Peer, Yves

    2004-01-01

    Background The identification of relevant biological features in large and complex datasets is an important step towards gaining insight in the processes underlying the data. Other advantages of feature selection include the ability of the classification system to attain good or even better solutions using a restricted subset of features, and a faster classification. Thus, robust methods for fast feature selection are of key importance in extracting knowledge from complex biological data. Results In this paper we present a novel method for feature subset selection applied to splice site prediction, based on estimation of distribution algorithms, a more general framework of genetic algorithms. From the estimated distribution of the algorithm, a feature ranking is derived. Afterwards this ranking is used to iteratively discard features. We apply this technique to the problem of splice site prediction, and show how it can be used to gain insight into the underlying biological process of splicing. Conclusion We show that this technique proves to be more robust than the traditional use of estimation of distribution algorithms for feature selection: instead of returning a single best subset of features (as they normally do) this method provides a dynamical view of the feature selection process, like the traditional sequential wrapper methods. However, the method is faster than the traditional techniques, and scales better to datasets described by a large number of features. PMID:15154966

  12. What Causes Cardiomyopathy?

    MedlinePlus

    ... and can damage the organs, including the heart. Sarcoidosis : A disease that causes inflammation and can affect ... believe that an abnormal immune response may cause sarcoidosis. This abnormal response causes tiny lumps of cells ...

  13. Common Cause Failure Modeling

    NASA Technical Reports Server (NTRS)

    Hark, Frank; Britton, Paul; Ring, Robert; Novack, Steven

    2015-01-01

    Space Launch System (SLS) Agenda: Objective; Key Definitions; Calculating Common Cause; Examples; Defense against Common Cause; Impact of varied Common Cause Failure (CCF) and abortability; Response Surface for various CCF Beta; Takeaways.

  14. What Causes Pericarditis?

    MedlinePlus

    ... this page from the NHLBI on Twitter. What Causes Pericarditis? In many cases, the cause of pericarditis (both acute and chronic) is unknown. Viral infections are likely a common cause of pericarditis, although the virus may never be ...

  15. Three featured plenary sessions

    NASA Astrophysics Data System (ADS)

    2012-07-01

    The conference included three plenary sessions. The plenary on Governance, Security, Economy, and the Ecosystem of the Changing Arctic featured Vera Alexander, president, Arctic Research Consortium of the U.S.; Alan Thornhill, chief environmental officer, U.S. Department of the Interior's Bureau of Ocean Energy Management; and Fran Ulmer, chair, U.S. Arctic Research Commission. A plenary on the U.N. Convention on the Law of the Sea featured Ambassador David Balton, deputy assistant secretary for oceans and fisheries, U.S. Department of State; and Rear Admiral Frederick Kenney Jr., judge advocate general and chief counsel, U.S. Coast Guard. The plenary on Science and the 21st Century featured Phil Keslin, chief technology officer, small lab within Google.

  16. Escalator design features evaluation

    NASA Technical Reports Server (NTRS)

    Zimmerman, W. F.; Deshpande, G. K.

    1982-01-01

    Escalators are available with design features such as dual speed (90 and 120 fpm), mat operation and flat steps. These design features were evaluated based on the impact of each on capital and operating costs, traffic flow, and safety. A human factors engineering model was developed to analyze the need for flat steps at various speeds. Mat operation of escalators was found to be cost effective in terms of energy savings. Dual speed operation of escalators with the higher speed used during peak hours allows for efficient operation. A minimum number of flat steps required as a function of escalator speed was developed to ensure safety for the elderly.

  17. MCNP4A: Features and philosophy

    SciTech Connect

    Hendricks, J.S.

    1993-05-01

    This paper describes MCNP, states its philosophy, introduces a number of new features becoming available with version MCNP4A, and answers a number of questions asked by participants in the workshop. MCNP is a general-purpose three-dimensional neutron, photon and electron transport code. Its philosophy is ``Quality, Value and New Features.`` Quality is exemplified by new software quality assurance practices and a program of benchmarking against experiments. Value includes a strong emphasis on documentation and code portability. New features are the third priority. MCNP4A is now available at Los Alamos. New features in MCNP4A include enhanced statistical analysis, distributed processor multitasking, new photon libraries, ENDF/B-VI capabilities, X-Windows graphics, dynamic memory allocation, expanded criticality output, periodic boundaries, plotting of particle tracks via SABRINA, and many other improvements. 23 refs.

  18. Segmentation of Infant Hippocampus Using Common Feature Representations Learned for Multimodal Longitudinal Data

    PubMed Central

    Guo, Yanrong; Wu, Guorong; Yap, Pew-Thian; Jewells, Valerie; Lin, Weili

    2016-01-01

    Aberrant development of the human brain during the first year after birth is known to cause critical implications in later stages of life. In particular, neuropsychiatric disorders, such as attention deficit hyperactivity disorder (ADHD), have been linked with abnormal early development of the hippocampus. Despite its known importance, studying the hippocampus in infant subjects is very challenging due to the significantly smaller brain size, dynamically varying image contrast, and large across-subject variation. In this paper, we present a novel method for effective hippocampus segmentation by using a multi-atlas approach that integrates the complementary multimodal information from longitudinal T1 and T2 MR images. In particular, considering the highly heterogeneous nature of the longitudinal data, we propose to learn their common feature representations by using hierarchical multi-set kernel canonical correlation analysis (CCA). Specifically, we will learn (1) within-time-point common features by projecting different modality features of each time point to its own modality-free common space, and (2) across-time-point common features by mapping all time-point-specific common features to a global common space for all time points. These final features are then employed in patch matching across different modalities and time points for hippocampus segmentation, via label propagation and fusion. Experimental results demonstrate the improved performance of our method over the state-of-the-art methods. PMID:27019875

  19. Vibrations Caused By Cracked Turbopump Bearing Race

    NASA Technical Reports Server (NTRS)

    Goggin, David G.; Dweck, Robert A.

    1990-01-01

    Expansion gives rise to eccentricity. Report presents analysis of dynamic effects caused by cracking of inner race of ball bearing in turbopump. Crack manifested itself via increase in vibrations synchronous with rotation and smaller increase at twice frequency of rotation. Analysis conducted to verify these increases were caused solely by crack and to understand implications for future such cracks.

  20. What Causes COPD? | NIH MedlinePlus the Magazine

    MedlinePlus

    ... please turn JavaScript on. Feature: The Challenge of COPD What Causes COPD? Past Issues / Fall 2014 Table of Contents Long- ... and the airways usually is the cause of COPD. In the United States, the most common irritant ...

  1. Comprehensive Analysis of Neptune's Features

    NASA Astrophysics Data System (ADS)

    Karkoschka, Erich

    2007-07-01

    Hubble took an amazing data set of Neptune in nine GO programs between 1994 and 2006, consisting of 408 WFPC2 exposures with several filters present in each program. The PIs of these programs, Hammel, Sromovsky, and Rages, published a variety of results about Neptune's atmosphere based on each program. However, the typical size of the grants for each program did not allow all scientific questions of these rich data sets to be addressed.I propose to analyze these 400 images to create a consistent data set spanning 12 years, and I will make even the intermediate results available, such as 400 consistently calibrated images. The combined data set will then be able to address more far reaching questions than could be done by single data sets. Whereas previous studies focused on only a few center-to-limb measurements for a limited selection of latitudes and wavelengths, I will investigate the whole data set and analyze 16,000 center-to-limb curves. I will use the principal component analysis and various statistical tests to find the hidden variations on Neptune. I created software for a similar project on Hubble's Saturn images. I am ready to adapt and apply it to Hubble's Neptune images.The huge number of variable features on Neptune contain an ideal probe about atmospheric dynamics. Previous investigations have only scratched pieces of the surface of this treasure. It is time for a comprehensive study of the whole data to discover fundamenatal insights about atmospheric dynamics.

  2. Main features of meiosis

    SciTech Connect

    1993-12-31

    Chapter 17, outlines the main features of meiosis, beginning with its significance and proceeding through the meiotic stages. Meiosis is the most important modification of mitosis because it is the reduction division that gives rise to the haploid generation in the life cycle. 17 refs., 6 figs.

  3. Assistive Technologies, Feature Issue.

    ERIC Educational Resources Information Center

    Wobschall, Rachel, Ed.; Lakin, Charlie, Ed.

    1995-01-01

    This feature issue of a newsletter on community integration of individuals with developmental disabilities considers the role of assistive technologies. It describes efforts to utilize consumer direction, public policy, creativity, energy, and professional know-how in the pursuit of technology-based opportunities to enhance community inclusion,…

  4. Feature- Spring 2010

    Cancer.gov

    NCI CAM News is a twice yearly newsletter produced by OCCAM to bring you information on the National Cancer Institute's latest CAM activities. Featured in the newsletter are: Highlights of NCI-sponsored CAM research Resources for researchers such as funding opportunities and grant writing workshops Upcoming meetings and lectures

  5. On equivalent parameter learning in simplified feature space based on Bayesian asymptotic analysis.

    PubMed

    Yamazaki, Keisuke

    2012-07-01

    Parametric models for sequential data, such as hidden Markov models, stochastic context-free grammars, and linear dynamical systems, are widely used in time-series analysis and structural data analysis. Computation of the likelihood function is one of primary considerations in many learning methods. Iterative calculation of the likelihood such as the model selection is still time-consuming though there are effective algorithms based on dynamic programming. The present paper studies parameter learning in a simplified feature space to reduce the computational cost. Simplifying data is a common technique seen in feature selection and dimension reduction though an oversimplified space causes adverse learning results. Therefore, we mathematically investigate a condition of the feature map to have an asymptotically equivalent convergence point of estimated parameters, referred to as the vicarious map. As a demonstration to find vicarious maps, we consider the feature space, which limits the length of data, and derive a necessary length for parameter learning in hidden Markov models. PMID:22503779

  6. Unidentified Infrared Emission Features

    NASA Astrophysics Data System (ADS)

    Joblin, Christine

    2015-03-01

    When referring to unidentified infrared emission features, one has in mind the series of aromatic IR bands (AIBs) between 3.3 and 15 μm that are observed in emission in many environments where UV photons irradiate interstellar matter. These bands are now used by astronomers to classify objects and characterize local physical conditions. However, a deep analysis cannot proceed without understanding the properties of the band carriers. Large polycyclic aromatic hydrocarbon molecules are attractive candidates but interstellar species are still poorly characterized. Various studies emphasize the need for tackling the link between molecular aromatic species, aliphatic material and very small carbonaceous grains. Other unidentified emission features such as the 6.9, 21 and 30 μm bands could be involved in the evolutionary scenario.

  7. North Polar Features

    NASA Technical Reports Server (NTRS)

    2004-01-01

    28 November 2004 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows banded terrain of the north polar region of Mars. The bands are exposures of layered material, possibly composed of dust and ice. The dark, rounded to elliptical mounds in this image might be the locations of ancient sand dunes that were completely buried in the north polar layered material. In more recent times, these mounds have been exhumed from within the layered material. Alternatively, the dark features are not ancient, exhumed dunes, but perhaps the remnants of a dark layer of material that once covered the entire area shown in the image. These features are located near 79.9oN, 31.4oW. The image covers an area about 3 km (1.9 mi) wide. Sunlight illuminates the scene from the lower left.

  8. Isidis Planitia Features

    NASA Technical Reports Server (NTRS)

    2004-01-01

    26 June 2004 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows some of the most typical features of Isidis Planitia at full (1.5 meters -- 5 feet -- per pixel) resolution. The typical features are: (1) light-toned, ripple-like dunes and (2) mounds with summit pits. The dunes are formed by wind. The double-cone feature in the lower right quarter of the image is similar to many mounds and chains of mounds or cones found all across Isidis Planitia. These were seen at lower resolution in Viking orbiter images in the 1970s and were generally considered to be either small volcanoes or ice-cored mounds known as pingoes. With high resolution MOC images, it became apparent that many of these mounds may simply be the remnants of crater and pit chain floors, elevated above the surrounding plains as the layers of rock into which they formed were stripped away. Like much of Mars, there are more questions than answers. This image is located near 8.6oN, 268.2oW, and covers an area about 1.1 km (0.7 mi) wide. Sunlight illuminates the scene from the left/lower left.

  9. Ceraunius Tholus Feature

    NASA Technical Reports Server (NTRS)

    2004-01-01

    11 December 2004 Today's Mars Picture of the Day features two images. The top picture is a mosaic of Viking orbiter images acquired in the late 1970s. The lower image is a high resolution picture from the Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC). The Viking mosaic shows Ceraunius Tholus, a volcano in the Tharsis region that was first viewed in images obtained by Mariner 9 in 1972. Several channels run down the slope of the Ceraunius Tholus volcano. The deepest of those channels ends in an elliptical crater. The elliptical crater was formed by a very oblique meteor impact. Where the channel meets the floor of the elliptical crater, there is a small mound of material. Presumably, this material was deposited in the elliptical crater after running down through the channel on the volcano's northwest flank.

    Near the top/center of the mound in the elliptical crater is a small, circular depression. Some have speculated for years that this depression is related to volcanism, others thought that it may be an impact crater. The MGS MOC image (lower of the two images) shows that crater. It is not the source of lava flows or any other volcanic features. Most likely, it is an old impact crater. This feature is located near 25.2oN, 97.7oW. The MOC image covers an area approximately 3 km (1.9 mi) wide and is illuminated by sunlight from the lower left.

  10. [Hereditary angioedema causing colocolic intussusception].

    PubMed

    Sanchez, A; Ecochard, A; Maestracci, M; Rodiere, M

    2008-03-01

    Hereditary angioedema is a rare, autosomal dominant disease inherited. The cause is a quantitative or qualitative congenital deficit in C1 inhibitor. Various clinical symptoms, in particular of sub-cutaneous, upper airways and digestive origin, have been described. Life threatening conditions may be observed. Little information is available on digestive tract localization corresponding to intestinal intussusception associated with hereditary angioedema in children. We report a case of hereditary angioedema observed in a 15-years-old girl who presented such features. We propose a review of the literature and discuss the curative treatment of digestive crisis in children with hereditary angioedema. PMID:18329867

  11. Featured Image: Modeling Supernova Remnants

    NASA Astrophysics Data System (ADS)

    Kohler, Susanna

    2016-05-01

    This image shows a computer simulation of the hydrodynamics within a supernova remnant. The mixing between the outer layers (where color represents the log of density) is caused by turbulence from the Rayleigh-Taylor instability, an effect that arises when the expanding core gas of the supernova is accelerated into denser shell gas. The past standard for supernova-evolution simulations was to perform them in one dimension and then, in post-processing, manually smooth out regions that undergo Rayleigh-Taylor turbulence (an intrinsically multidimensional effect). But in a recent study, Paul Duffell (University of California, Berkeley) has explored how a 1D model could be used to reproduce the multidimensional dynamics that occur in turbulence from this instability. For more information, check out the paper below!CitationPaul C. Duffell 2016 ApJ 821 76. doi:10.3847/0004-637X/821/2/76

  12. What Causes Anemia?

    MedlinePlus

    ... page from the NHLBI on Twitter. What Causes Anemia? The three main causes of anemia are: Blood ... the blood and can lead to anemia. Aplastic Anemia Some infants are born without the ability to ...

  13. What Causes Pulmonary Hypertension?

    MedlinePlus

    ... from the NHLBI on Twitter. What Causes Pulmonary Hypertension? Pulmonary hypertension (PH) begins with inflammation and changes in the ... different types of PH. Group 1 pulmonary arterial hypertension (PAH) may have no known cause, or the ...

  14. What Causes Cystic Fibrosis?

    MedlinePlus

    ... What Causes Cystic Fibrosis? A defect in the CFTR gene causes cystic fibrosis (CF). This gene makes ... and very salty sweat. Research suggests that the CFTR protein also affects the body in other ways. ...

  15. What Causes Cancer?

    MedlinePlus

    ... articles window. My Saved Articles » My ACS » What Causes Cancer? Cancer is a complex group of diseases with ... cancer. Learn About Cancer Topics Cancer Basics What Causes Cancer? Breast Cancer Colon/Rectum Cancer Lung Cancer Prostate ...

  16. What Causes Polycythemia Vera?

    MedlinePlus

    ... this page from the NHLBI on Twitter. What Causes Polycythemia Vera? Primary Polycythemia Polycythemia vera (PV) also ... in the body's JAK2 gene is the main cause of PV. The JAK2 gene makes a protein ...

  17. What Causes Menstrual Irregularities?

    MedlinePlus

    ... menstrual flow Smoking Depression Never having given birth Endometriosis Chronic uterine infection Additional causes of menstrual irregularity include 1 : Endometriosis Endocrine gland-related causes Poorly controlled diabetes Polycystic ...

  18. Fluorescence and piezoresistive cantilever sensing of trinitrotoluene by an upper-rim tetrabenzimidazole conjugate of calix[4]arene and delineation of the features of the complex by molecular dynamics.

    PubMed

    Kandpal, Manoj; Bandela, Anil Kumar; Hinge, Vijaya Kumar; Rao, V Ramgopal; Rao, Chebrolu Pulla

    2013-12-26

    A new benzimidazole-functionalized calix[4]arene receptor (R) was synthesized and characterized. The receptor R shows better selectivity toward trinitrotoluene (TNT) compared to the other nitro explosives in solution, which also retains its effectiveness for solid-phase detection. The chemical interactions of the molecule with different nitro explosive analytes were studied by fluorescence spectroscopy and by a molecular dynamics approach. The molecular dynamics studies show a 1:3 complex between R and TNT, and hence high sensitivity was imparted by fluorescence studies. The detection of explosive vapors in ambient conditions was tested by using a sensitive coating layer of R on an SU-8/CB-based piezoresistive cantilever surface. The developed device showed large sensitivity toward TNT compared to cyclotrimethylenetrinitramine (RDX) and pentaerythritol tetranitrate (PETN) in the solid state at their respective vapor pressures at room temperature. The detection sensitivity of the device was estimated to be 35 mV for TNT at ambient conditions. Moreover, the sensor does not show a response when exposed to humidity. These results demonstrate that R can be used as one of the coating materials for a cantilever for the detection of TNT using piezoresistivity measurement. R can also detect the explosives in solution with high sensitivity and selectivity by fluorescence spectroscopy. PMID:24320549

  19. What Causes Cardiogenic Shock?

    MedlinePlus

    ... page from the NHLBI on Twitter. What Causes Cardiogenic Shock? Immediate Causes Cardiogenic shock occurs if the heart suddenly can't pump ... to the body. The most common cause of cardiogenic shock is damage to the heart muscle from a ...

  20. Do Allergies Cause Asthma?

    MedlinePlus

    ... Help a Friend Who Cuts? Do Allergies Cause Asthma? KidsHealth > For Teens > Do Allergies Cause Asthma? Print A A A Text Size en español ¿Las alergias provocan asma? Do allergies cause asthma? The answer to that question is: yes and ...

  1. Electronic Nose Feature Extraction Methods: A Review

    PubMed Central

    Yan, Jia; Guo, Xiuzhen; Duan, Shukai; Jia, Pengfei; Wang, Lidan; Peng, Chao; Zhang, Songlin

    2015-01-01

    Many research groups in academia and industry are focusing on the performance improvement of electronic nose (E-nose) systems mainly involving three optimizations, which are sensitive material selection and sensor array optimization, enhanced feature extraction methods and pattern recognition method selection. For a specific application, the feature extraction method is a basic part of these three optimizations and a key point in E-nose system performance improvement. The aim of a feature extraction method is to extract robust information from the sensor response with less redundancy to ensure the effectiveness of the subsequent pattern recognition algorithm. Many kinds of feature extraction methods have been used in E-nose applications, such as extraction from the original response curves, curve fitting parameters, transform domains, phase space (PS) and dynamic moments (DM), parallel factor analysis (PARAFAC), energy vector (EV), power density spectrum (PSD), window time slicing (WTS) and moving window time slicing (MWTS), moving window function capture (MWFC), etc. The object of this review is to provide a summary of the various feature extraction methods used in E-noses in recent years, as well as to give some suggestions and new inspiration to propose more effective feature extraction methods for the development of E-nose technology. PMID:26540056

  2. Features of MCNP6

    NASA Astrophysics Data System (ADS)

    Goorley, T.; James, M.; Booth, T.; Brown, F.; Bull, J.; Cox, L. J.; Durkee, J.; Elson, J.; Fensin, M.; Forster, R. A.; Hendricks, J.; Hughes, H. G.; Johns, R.; Kiedrowski, B.; Martz, R.; Mashnik, S.; McKinney, G.; Pelowitz, D.; Prael, R.; Sweezy, J.; Waters, L.; Wilcox, T.; Zukaitis, T.

    2014-06-01

    MCNP6 is simply and accurately described as the merger of MCNP5 and MCNPX capabilities, but it is much more than the sum of these two computer codes. MCNP6 is the result of six years of effort by the MCNP5 and MCNPX code development teams. These groups of people, residing in Los Alamos National Laboratory's X Computational Physics Division, Monte Carlo Codes Group (XCP-3) and Nuclear Engineering and Nonproliferation Division, Radiation Transport Modeling Team (NEN-5) respectively, have combined their code development efforts to produce the next evolution of MCNP. While maintenance and major bug fixes will continue for MCNP5 1.60 and MCNPX 2.7.0 for upcoming years, new code development capabilities only will be developed and released in MCNP6. In fact, the initial release of MCNP6 contains numerous new features not previously found in either code. These new features are summarized in this document. Packaged with MCNP6 is also the new production release of the ENDF/B-VII.1 nuclear data files usable by MCNP. The high quality of the overall merged code, usefulness of these new features, along with the desire in the user community to start using the merged code, have led us to make the first MCNP6 production release: MCNP6 version 1. High confidence in the MCNP6 code is based on its performance with the verification and validation test suites, comparisons to its predecessor codes, our automated nightly software debugger tests, the underlying high quality nuclear and atomic databases, and significant testing by many beta testers.

  3. qFeature

    SciTech Connect

    2015-09-14

    This package contains statistical routines for extracting features from multivariate time-series data which can then be used for subsequent multivariate statistical analysis to identify patterns and anomalous behavior. It calculates local linear or quadratic regression model fits to moving windows for each series and then summarizes the model coefficients across user-defined time intervals for each series. These methods are domain agnostic—but they have been successfully applied to a variety of domains, including commercial aviation and electric power grid data.

  4. qFeature

    Energy Science and Technology Software Center (ESTSC)

    2015-09-14

    This package contains statistical routines for extracting features from multivariate time-series data which can then be used for subsequent multivariate statistical analysis to identify patterns and anomalous behavior. It calculates local linear or quadratic regression model fits to moving windows for each series and then summarizes the model coefficients across user-defined time intervals for each series. These methods are domain agnostic—but they have been successfully applied to a variety of domains, including commercial aviation andmore » electric power grid data.« less

  5. Epignathus with Fetiform Features

    PubMed Central

    Kumar, Sunil Y; Shrikrishna, U; Shetty, Jayaprakash; Sitaram, Aishwarya

    2011-01-01

    Epignathus is an extremely rare oropharyngeal teratoma that commonly arises from the palate, leading to a high mortality (80–100%) due to airway obstruction in the neonatal period. We present a case of epignathus immature teratoma with fetiform features, originating from basisphenoid in a 28-week preterm male baby, who succumbed to death immediately after birth. Since epignathus is a life-threatening condition at the time of delivery, a prenatal diagnosis is essential to coordinate the treatment and appropriate management by securing the airway, either by endotracheal intubation or tracheostomy followed by complete resection of the tumor. PMID:21701667

  6. The dynamic of the splicing of bZIP60 and the proteins encoded by the spliced and unspliced mRNAs reveals some unique features during the activation of UPR in Arabidopsis thaliana.

    PubMed

    Parra-Rojas, Juan; Moreno, Adrian A; Mitina, Irina; Orellana, Ariel

    2015-01-01

    The unfolded protein response (UPR) is a signaling pathway that is activated when the workload of the endoplasmic reticulum (ER) is surpassed. IRE1 is a sensor involved in triggering the UPR and plays a key role in the unconventional splicing of an mRNA leading to the formation of a transcription factor that up-regulates the transcription of genes that play a role in restoring the homeostasis in the ER. In plants, bZIP60 is the substrate for IRE1; however, questions such as what is the dynamics of the splicing of bZIP60 and the fate of the proteins encoded by the spliced and unspliced forms of the mRNA, remain unanswered. In the present work, we analyzed the processing of bZIP60 by determining the levels of the spliced form mRNA in plants exposed to different conditions that trigger UPR. The results show that induction of ER stress increases the content of the spliced form of bZIP60 (bZIP60s) reaching a maximum, that depending on the stimuli, varied between 30 min or 2 hrs. In most cases, this was followed by a decrease in the content. In contrast to other eukaryotes, the splicing never occurred to full extent. The content of bZIP60s changed among different organs upon induction of the UPR suggesting that splicing is regulated differentially throughout the plant. In addition, we analyzed the distribution of a GFP-tagged version of bZIP60 when UPR was activated. A good correlation between splicing of bZIP60 and localization of the protein in the nucleus was observed. No fluorescence was observed under basal conditions, but interestingly, the fluorescence was recovered and found to co-localize with an ER marker upon treatment with an inhibitor of the proteasome. Our results indicate that the dynamics of bZIP60, both the mRNA and the protein, are highly dynamic processes which are tissue-specific and stimulus-dependent. PMID:25860807

  7. BUCKLE: A Model of Unobserved Cause Learning

    PubMed Central

    Luhmann, Christian C.; Ahn, Woo-kyoung

    2009-01-01

    Dealing with alternative causes is necessary to avoid making inaccurate causal inferences from covariation data. However, information about alternative causes is frequently unavailable, rendering them unobserved. The current article reviews the way in which current learning models deal, or could deal, with unobserved causes. A new model of causal learning, BUCKLE (bidirectional unobserved cause learning) extends existing models of causal learning by dynamically inferring information about unobserved, alternative causes. During the course of causal learning, BUCKLE continually computes the probability that an unobserved cause is present during a given observation and then uses the results of these inferences to learn the causal strengths of the unobserved as well as observed causes. The current results demonstrate that BUCKLE provides a better explanation of people's causal learning than the existing models. PMID:17638500

  8. Feature isolation and quantification of evolving datasets

    NASA Technical Reports Server (NTRS)

    1994-01-01

    Identifying and isolating features is an important part of visualization and a crucial step for the analysis and understanding of large time-dependent data sets (either from observation or simulation). In this proposal, we address these concerns, namely the investigation and implementation of basic 2D and 3D feature based methods to enhance current visualization techniques and provide the building blocks for automatic feature recognition, tracking, and correlation. These methods incorporate ideas from scientific visualization, computer vision, image processing, and mathematical morphology. Our focus is in the area of fluid dynamics, and we show the applicability of these methods to the quantification and tracking of three-dimensional vortex and turbulence bursts.

  9. Automated Extraction of Secondary Flow Features

    NASA Technical Reports Server (NTRS)

    Dorney, Suzanne M.; Haimes, Robert

    2005-01-01

    The use of Computational Fluid Dynamics (CFD) has become standard practice in the design and development of the major components used for air and space propulsion. To aid in the post-processing and analysis phase of CFD many researchers now use automated feature extraction utilities. These tools can be used to detect the existence of such features as shocks, vortex cores and separation and re-attachment lines. The existence of secondary flow is another feature of significant importance to CFD engineers. Although the concept of secondary flow is relatively understood there is no commonly accepted mathematical definition for secondary flow. This paper will present a definition for secondary flow and one approach for automatically detecting and visualizing secondary flow.

  10. Cutaneous melioidosis with unusual histological features.

    PubMed

    Yeo, B; Lee, J; Alagappan, U; Pan, J Y

    2016-04-01

    Melioidosis is caused by the saprophytic gram-negative bacillus Burkholderia pseudomallei, and has varied presentations, with cutaneous manifestations occurring in about 13% of cases. The usual histopathological features of melioidosis are suppurative to chronic granulomatous inflammation. Recommended treatment of melioidosis is sequential use of intravenous followed by oral antibiotics for a few months, although oral antibiotics alone can be used in primary cutaneous melioidosis. We report a case of cutaneous melioidosis in a healthy young man, with the unusual histopathological feature of lymphoplasmacytic inflammation, and failing an initial trial of oral antibiotics alone. PMID:26299451

  11. Probabilistic Slow Features for Behavior Analysis.

    PubMed

    Zafeiriou, Lazaros; Nicolaou, Mihalis A; Zafeiriou, Stefanos; Nikitidis, Symeon; Pantic, Maja

    2016-05-01

    A recently introduced latent feature learning technique for time-varying dynamic phenomena analysis is the so-called slow feature analysis (SFA). SFA is a deterministic component analysis technique for multidimensional sequences that, by minimizing the variance of the first-order time derivative approximation of the latent variables, finds uncorrelated projections that extract slowly varying features ordered by their temporal consistency and constancy. In this paper, we propose a number of extensions in both the deterministic and the probabilistic SFA optimization frameworks. In particular, we derive a novel deterministic SFA algorithm that is able to identify linear projections that extract the common slowest varying features of two or more sequences. In addition, we propose an expectation maximization (EM) algorithm to perform inference in a probabilistic formulation of SFA and similarly extend it in order to handle two and more time-varying data sequences. Moreover, we demonstrate that the probabilistic SFA (EM-SFA) algorithm that discovers the common slowest varying latent space of multiple sequences can be combined with dynamic time warping techniques for robust sequence time-alignment. The proposed SFA algorithms were applied for facial behavior analysis, demonstrating their usefulness and appropriateness for this task. PMID:26068878

  12. Recursive Feature Extraction in Graphs

    Energy Science and Technology Software Center (ESTSC)

    2014-08-14

    ReFeX extracts recursive topological features from graph data. The input is a graph as a csv file and the output is a csv file containing feature values for each node in the graph. The features are based on topological counts in the neighborhoods of each nodes, as well as recursive summaries of neighbors' features.

  13. Advanced Techniques for Root Cause Analysis

    Energy Science and Technology Software Center (ESTSC)

    2000-09-19

    Five items make up this package, or can be used individually. The Chronological Safety Management Template utilizes a linear adaptation of the Integrated Safety Management System laid out in the form of a template that greatly enhances the ability of the analyst to perform the first step of any investigation which is to gather all pertinent facts and identify causal factors. The Problem Analysis Tree is a simple three (3) level problem analysis tree whichmore » is easier for organizations outside of WSRC to use. Another part is the Systemic Root Cause Tree. One of the most basic and unique features of Expanded Root Cause Analysis is the Systemic Root Cause portion of the Expanded Root Cause Pyramid. The Systemic Root Causes are even more basic than the Programmatic Root Causes and represent Root Causes that cut across multiple (if not all) programs in an organization. the Systemic Root Cause portion contains 51 causes embedded at the bottom level of a three level Systemic Root Cause Tree that is divided into logical, organizationally based categorie to assist the analyst. The Computer Aided Root Cause Analysis that allows the analyst at each level of the Pyramid to a) obtain a brief description of the cause that is being considered, b) record a decision that the item is applicable, c) proceed to the next level of the Pyramid to see only those items at the next level of the tree that are relevant to the particular cause that has been chosen, and d) at the end of the process automatically print out a summary report of the incident, the causal factors as they relate to the safety management system, the probable causes, apparent causes, Programmatic Root Causes and Systemic Root Causes for each causal factor and the associated corrective action.« less

  14. Causes for "ghost" manifolds

    NASA Astrophysics Data System (ADS)

    Borok, S.; Goldfarb, I.; Gol'dshtein, V.

    2009-05-01

    The paper concerns intrinsic low-dimensional manifold (ILDM) method suggested in [Maas U, Pope SB. Simplifying chemical kinetics: intrinsic low-dimensional manifolds in composition space, combustion and flame 1992;88:239-64] for dimension reduction of models describing kinetic processes. It has been shown in a number of publications [Goldfarb I, Gol'dshtein V, Maas U. Comparative analysis of two asymptotic approaches based on integral manifolds. IMA J Appl Math 2004;69:353-74; Kaper HG, Kaper TJ, Asymptotic analysis of two reduction methods for systems of chemical reactions. Phys D 2002;165(1-2):66-93; Rhodes C, Morari M, Wiggins S. Identification of the low order manifolds: validating the algorithm of Maas and Pope. Chaos 1999;9(1):108-23] that the ILDM-method works successfully and the intrinsic low-dimensional manifolds belong to a small vicinity of invariant slow manifolds. The ILDM-method has a number of disadvantages. One of them is appearance of so-called "ghost"-manifolds, which do not have connection to the system dynamics [Borok S, Goldfarb I, Gol'dshtein V. "Ghost" ILDM - manifolds and their discrimination. In: Twentieth Annual Symposium of the Israel Section of the Combustion Institute, Beer-Sheva, Israel; 2004. p. 55-7; Borok S, Goldfarb I, Gol'dshtein V. About non-coincidence of invariant manifolds and intrinsic low-dimensional manifolds (ILDM). CNSNS 2008;71:1029-38; Borok S, Goldfarb I, Gol'dshtein V, Maas U. In: Gorban AN, Kazantzis N, Kevrekidis YG, Ottinger HC, Theodoropoulos C, editors. "Ghost" ILDM-manifolds and their identification: model reduction and coarse-graining approaches for multiscale phenomena. Berlin-Heidelberg-New York: Springer; 2006. p. 55-80; Borok S, Goldfarb I, Gol'dshtein V. On a modified version of ILDM method and its asymptotic analysis. IJPAM 2008; 44(1): 125-50; Bykov V, Goldfarb I, Gol'dshtein V, Maas U. On a modified version of ILDM approach: asymptotic analysis based on integral manifolds. IMA J Appl Math 2006

  15. Feature engineering for drug name recognition in biomedical texts: feature conjunction and feature selection.

    PubMed

    Liu, Shengyu; Tang, Buzhou; Chen, Qingcai; Wang, Xiaolong; Fan, Xiaoming

    2015-01-01

    Drug name recognition (DNR) is a critical step for drug information extraction. Machine learning-based methods have been widely used for DNR with various types of features such as part-of-speech, word shape, and dictionary feature. Features used in current machine learning-based methods are usually singleton features which may be due to explosive features and a large number of noisy features when singleton features are combined into conjunction features. However, singleton features that can only capture one linguistic characteristic of a word are not sufficient to describe the information for DNR when multiple characteristics should be considered. In this study, we explore feature conjunction and feature selection for DNR, which have never been reported. We intuitively select 8 types of singleton features and combine them into conjunction features in two ways. Then, Chi-square, mutual information, and information gain are used to mine effective features. Experimental results show that feature conjunction and feature selection can improve the performance of the DNR system with a moderate number of features and our DNR system significantly outperforms the best system in the DDIExtraction 2013 challenge. PMID:25861377

  16. Outer packet sets and feature prediction of computer virus

    NASA Astrophysics Data System (ADS)

    Zhang, Ling

    2014-10-01

    The packet sets model was proposed by Prof. Shi in 2008. A packet sets is a set pair composed of internal and outer packet sets, and it has dynamic characteristic. Using packet sets theory, this paper gives the feature prediction of computer virus based on outer packet sets. The concept of virus screening-filtering is given, furthermore, the virus screening-filtering order theorem, composite virus screening-filtering theorem and virus screening-filtering rule are presented. A prediction method of computer virus feature is given based on the results. The outer packet sets is a new tool in the research of the prediction of dynamic virus feature.

  17. Causes and effects.

    PubMed

    Cone, Carol L; Feldman, Mark A; DaSilva, Alison T

    2003-07-01

    Most companies make charitable donations, but few approach their contributions with an eye toward enhancing their brands. Those that do take such an approach commit talent and know-how, not just dollars, to a pressing but carefully chosen social need and then tell the world about the cause and their service to it. Through the association, both the business and the cause benefit in ways they could not otherwise. Organizations such as Avon, ConAgra Foods, and Chevrolet have recognized that a sustained cause-branding program can improve their reputations, boost their employees' morale, strengthen relations with business partners, and drive sales. And the targeted causes receive far more money than they could have from direct corporate gifts alone. The authors examine these best practices and offer four principles for building successful cause-branding programs. First, they say, a company should select a cause that advances its corporate goals. That is, unless the competitive logic for supporting the cause is clear, a company shouldn't even consider putting its finite resources behind it. Second, a business should commit to a cause before picking its charitable partners. Otherwise, a cause-branding program may become too dependent on its partners. Third, a company should put all its assets to work, especially its employees. It should leverage the professional skills of its workers as well as its other assets such as distribution networks. And fourth, a company should promote its philanthropic initiatives through every possible channel. In addition to using the media, it should communicate its efforts through the Web, annual reports, direct mail, and so on. Cause branding is a way to turn the obligations of corporate citizenship into a valuable asset. When the cause is well chosen, the commitment genuine, and the program well executed, the cause helps the company, and the company helps the cause. PMID:12858714

  18. What Causes Aplastic Anemia?

    MedlinePlus

    ... to aplastic anemia. Examples include Fanconi anemia , Shwachman-Diamond syndrome, dyskeratosis (DIS-ker-ah-TO-sis) congenita, and Diamond-Blackfan anemia. Rate This Content: NEXT >> Featured Video ...

  19. What Causes Heart Disease?

    MedlinePlus

    ... through menopause. Rate This Content: NEXT >> Featured Video All of Our Stories Are Red: Yaskary's Story 04/ ... part of the National Institutes of Health (NIH). All of Our Stories Are Red: Eileen's Story 04/ ...

  20. Extracting features to recognize partially occluded objects

    NASA Astrophysics Data System (ADS)

    Koch, Mark W.; Ramamurthy, Arjun

    1991-12-01

    Noisy objects, partially occluded objects, and objects in random positions and orientations cause significant problems for current robotic vision systems. In the past, an association graph has formed the basis for many model based matching methods. However, the association graph has many false nodes due to local and noisy features. Objects having similar local structures create many false arcs in the association graph. The maximal clique recursive and tree search procedures for finding sets of structurally compatible matches have exponential time complexity, due to these false arcs and nodes. This represents a real problem as the number of objects appearing in the scene and the model set size increase. Our approach is similar to randomized string matching algorithms. Points on edges represent the model features. A fingerprint defines a subset of model features that uniquely identify the model. These fingerprints remove the ambiguities and inconsistencies present in the association graph and eliminate the problems of Turney's connected salient features. The vision system chooses the fingerprints at random, preventing a knowledgeable adversary from constructing examples that destroy the advantages of fingerprinting. Fingerprints consist of local model features called point vectors. We have developed a heuristic approach for extracting fingerprints from a set of model objects. A list of connected and unconnected scene edges represent the scene. A Hough transform type approach matches model fingerprints to scene features. Results are given for scenes containing varying amounts of occlusion.

  1. Dynamics of Entropy and Nonclassicality Features of the Interaction between a ⋄-type Four-Level Atom and a Single-Mode Field in the Presence of Intensity-Dependent Coupling and Kerr Nonlinearity

    NASA Astrophysics Data System (ADS)

    H. R., Baghshahi; M. K., Tavassoly; Behjat, A.

    2014-09-01

    The interaction between a ⋄-type four-level atom and a single-mode field in the presence of Kerr medium with intensity-dependent coupling involving multi-photon processes has been studied. Using the generalized (nonlinear) Jaynes—Cummings model, the exact analytical solution of the wave function for the considered system under particular condition, has been obtained when the atom is initially excited to the topmost level and the field is in a coherent state. Some physical properties of the atom-field entangled state such as linear entropy showing the entanglement degree, Mandel parameter, mean photon number and normal squeezing of the resultant state have been calculated. The effects of Kerr medium, detuning and the intensity-dependent coupling on the temporal behavior of the latter mentioned nonclassical properties have been investigated. It is shown that by appropriately choosing the evolved parameters in the interaction process, each of the above nonclassicality features, which are of special interest in quantum optics as well as quantum information processing, can be revealed.

  2. Multispectral Image Feature Points

    PubMed Central

    Aguilera, Cristhian; Barrera, Fernando; Lumbreras, Felipe; Sappa, Angel D.; Toledo, Ricardo

    2012-01-01

    This paper presents a novel feature point descriptor for the multispectral image case Far-Infrared and Visible Spectrum images. It allows matching interest points on images of the same scene but acquired in different spectral bands. Initially, points of interest are detected on both images through a SIFT-like based scale space representation. Then, these points are characterized using an Edge Oriented Histogram (EOH) descriptor. Finally, points of interest from multispectral images are matched by finding nearest couples using the information from the descriptor. The provided experimental results and comparisons with similar methods show both the validity of the proposed approach as well as the improvements it offers with respect to the current state-of-the-art.

  3. More features, greater connectivity.

    PubMed

    Hunt, Sarah

    2015-09-01

    Changes in our political infrastructure, the continuing frailties of our economy, and a stark growth in population, have greatly impacted upon the perceived stability of the NHS. Healthcare teams have had to adapt to these changes, and so too have the technologies upon which they rely to deliver first-class patient care. Here Sarah Hunt, marketing co-ordinator at Aid Call, assesses how the changing healthcare environment has affected one of its fundamental technologies - the nurse call system, argues the case for wireless such systems in terms of what the company claims is greater adaptability to changing needs, and considers the ever-wider range of features and functions available from today's nurse call equipment, particularly via connectivity with both mobile devices, and ancillaries ranging from enuresis sensors to staff attack alert 'badges'. PMID:26548128

  4. Arc Evolution in Response to the Subduction of Buoyant Features

    NASA Astrophysics Data System (ADS)

    Jenkins, Luke; Fourel, Loic; Goes, Saskia; Morra, Gabriele

    2015-04-01

    The subduction of buoyant features such as aseismic ridges or oceanic plateaux has been invoked to explain arc deformation, flat subduction and increase in seismic coupling. Other studies have challenged these ideas, attributing a larger role to the overriding plate. However, many open questions remain about the dynamics of the relative simple case of a single freely subducting plate. How big does a plateau need to be to change the arc shape? What is the control of plate's strength on the impact of buoyant features? How do the velocities adapt to the subduction of less dense material? In the present study, we propose a systematic approach in order to tackle these questions. We use a new 3-D coupled fluid-solid subduction model where the interaction between the slab and the isoviscous mantle is only calculated on the slab surface, significantly increasing computational efficiency. The oceanic plate rheology is visco-elasto-plastic and its top surface is free. We find that arc shape is significantly altered by the subduction of buoyant plateaux. Along the subduction plane through the plateau and depending on its size, the dip angle and the retreat velocity significantly decrease. Flat subduction is obtained in the case of large and strongly buoyant plateau/ridge. An interesting feature is that retreat velocity increases right after the plateau or ridge has finished subducting in order to catch up with the rest of the plate. The gradient in retreat velocity obtained along the trench may cause the slab to have a heterogeneous response to ridge push, eventually leading to slab advance where buoyant material is present. We apply our models to the Izu-Bonin-Marianas (IBM) trench and propose that subduction of the buoyant Caroline Island Ridge at the southern edge of the Mariana trench can explain both trench motion history and the current morphology of the IBM slab as imaged by seismic tomography.

  5. Feature Tracking Using Reeb Graphs

    SciTech Connect

    Weber, Gunther H.; Bremer, Peer-Timo; Day, Marcus S.; Bell, John B.; Pascucci, Valerio

    2010-08-02

    Tracking features and exploring their temporal dynamics can aid scientists in identifying interesting time intervals in a simulation and serve as basis for performing quantitative analyses of temporal phenomena. In this paper, we develop a novel approach for tracking subsets of isosurfaces, such as burning regions in simulated flames, which are defined as areas of high fuel consumption on a temperature isosurface. Tracking such regions as they merge and split over time can provide important insights into the impact of turbulence on the combustion process. However, the convoluted nature of the temperature isosurface and its rapid movement make this analysis particularly challenging. Our approach tracks burning regions by extracting a temperature isovolume from the four-dimensional space-time temperature field. It then obtains isosurfaces for the original simulation time steps and labels individual connected 'burning' regions based on the local fuel consumption value. Based on this information, a boundary surface between burning and non-burning regions is constructed. The Reeb graph of this boundary surface is the tracking graph for burning regions.

  6. Colonization of cashew plants by Lasiodiplodia theobromae: Microscopical features

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Lasiodiplodia theobromae is a phytopathogenic fungus causing gummosis, a threatening disease for cashew plants in Brazil. In an attempt to investigate the ultrastructural features of the pathogen colonization and its response to immunofluorescence labeling, light, confocal and electron microscope st...

  7. Characteristics of electron near-wall transport under two-dimensional dynamic sheath in a Hall effect thruster

    SciTech Connect

    Li Hong; Liu Hui; Yu Daren; Zhang Fengkui

    2010-07-15

    It is demonstrated that the features of measured electron current profile in the near-wall region of a Hall effect thruster are mainly due to the substantive breakdown of electron Hall drifts caused by the azimuthal field of the two-dimensional dynamic sheath. This kind of cross-field diffusion shows its close connection with the anomalous electron transport.

  8. CMB polarization features from inflation versus reionization

    SciTech Connect

    Mortonson, Michael J.; Dvorkin, Cora; Peiris, Hiranya V.; Hu, Wayne

    2009-05-15

    The angular power spectrum of the cosmic microwave background temperature anisotropy observed by WMAP has an anomalous dip at l{approx}20 and a bump at l{approx}40. One explanation for this structure is the presence of features in the primordial curvature power spectrum, possibly caused by a step in the inflationary potential. The detection of these features is only marginally significant from temperature data alone. However, the inflationary feature hypothesis predicts a specific shape for the E-mode polarization power spectrum with a structure similar to that observed in temperature at l{approx}20-40. Measurement of the CMB polarization on few-degree scales can therefore be used as a consistency check of the hypothesis. The Planck satellite has the statistical sensitivity to confirm or rule out the model that best fits the temperature features with 3{sigma} significance, assuming all other parameters are known. With a cosmic variance limited experiment, this significance improves to 8{sigma}. For tests of inflationary models that can explain both the dip and the bump in temperature, the primary source of uncertainty is confusion with polarization features created by a complex reionization history, which, at most, reduces the significance to 2.5{sigma} for Planck and 5{sigma}-6{sigma} for an ideal experiment. Smoothing of the polarization spectrum by a large tensor component only slightly reduces the ability of polarization to test for inflationary features, as does requiring that polarization is consistent with the observed temperature spectrum, given the expected low level of TE correlation on few-degree scales. If polarized foregrounds can be adequately subtracted, Planck will supply valuable evidence for or against features in the primordial power spectrum. A future high-sensitivity polarization satellite would enable a decisive test of the feature hypothesis and provide complementary information about the shape of a possible step in the inflationary potential.

  9. CMB polarization features from inflation versus reionization

    NASA Astrophysics Data System (ADS)

    Mortonson, Michael J.; Dvorkin, Cora; Peiris, Hiranya V.; Hu, Wayne

    2009-05-01

    The angular power spectrum of the cosmic microwave background temperature anisotropy observed by WMAP has an anomalous dip at ℓ˜20 and a bump at ℓ˜40. One explanation for this structure is the presence of features in the primordial curvature power spectrum, possibly caused by a step in the inflationary potential. The detection of these features is only marginally significant from temperature data alone. However, the inflationary feature hypothesis predicts a specific shape for the E-mode polarization power spectrum with a structure similar to that observed in temperature at ℓ˜20-40. Measurement of the CMB polarization on few-degree scales can therefore be used as a consistency check of the hypothesis. The Planck satellite has the statistical sensitivity to confirm or rule out the model that best fits the temperature features with 3σ significance, assuming all other parameters are known. With a cosmic variance limited experiment, this significance improves to 8σ. For tests of inflationary models that can explain both the dip and the bump in temperature, the primary source of uncertainty is confusion with polarization features created by a complex reionization history, which, at most, reduces the significance to 2.5σ for Planck and 5σ-6σ for an ideal experiment. Smoothing of the polarization spectrum by a large tensor component only slightly reduces the ability of polarization to test for inflationary features, as does requiring that polarization is consistent with the observed temperature spectrum, given the expected low level of TE correlation on few-degree scales. If polarized foregrounds can be adequately subtracted, Planck will supply valuable evidence for or against features in the primordial power spectrum. A future high-sensitivity polarization satellite would enable a decisive test of the feature hypothesis and provide complementary information about the shape of a possible step in the inflationary potential.

  10. A prototype feature system for feature retrieval using relationships

    USGS Publications Warehouse

    Choi, J.; Usery, E.L.

    2009-01-01

    Using a feature data model, geographic phenomena can be represented effectively by integrating space, theme, and time. This paper extends and implements a feature data model that supports query and visualization of geographic features using their non-spatial and temporal relationships. A prototype feature-oriented geographic information system (FOGIS) is then developed and storage of features named Feature Database is designed. Buildings from the U.S. Marine Corps Base, Camp Lejeune, North Carolina and subways in Chicago, Illinois are used to test the developed system. The results of the applications show the strength of the feature data model and the developed system 'FOGIS' when they utilize non-spatial and temporal relationships in order to retrieve and visualize individual features.

  11. Noonan syndrome: introduction and basic clinical features.

    PubMed

    Rohrer, T

    2009-12-01

    Noonan syndrome (NS) is a fairly common (1 per 1,000-2,500 live births) autosomal dominantly inherited disorder and the most common syndromal cause of congenital heart disease after Down's syndrome. The clinical features vary with age, but typical signs of NS include characteristic facial features with hypertelorism, down-slanting palpebral fissures, low-set posteriorly rotated ears, chest and spinal deformities, short stature, specific heart defects, learning disabilities and mild mental retardation. This article gives a brief introduction to NS and its basic clinical features using the established and generally accepted NS scoring system based on family history and facial, cardiac, growth, chest wall and other criteria. Aspects discussed include the definition, epidemiology, etiology, diagnosis and genetics of NS, as well as growth, skeletal and gonadal anomalies, pubertal development, ophthalmic and cutaneous abnormalities and the incidence of cancer in patients with NS. PMID:20029230

  12. Histologic features of granulomatous skin diseases.

    PubMed

    Mitteldorf, Christina; Tronnier, Michael

    2016-04-01

    Granulomatous disorders affecting the skin belong to a heterogeneous group of diseases, which were predominantly classified based on pathogenetic features. In infections diseases a granuloma is formed if an agent could not be eliminated by the immune system. Typical agents which cause granulomatous reactions are mycobacteria, fungal infections, especially extra European agent, which could effect the skin by, dissemination (e.g. histoplasmosis) or parasites, like leishmaniasis. PMID:27027748

  13. Recurrent breast abscesses caused by Corynebacterium minutissimum.

    PubMed

    Berger, S A; Gorea, A; Stadler, J; Dan, M; Zilberman, M

    1984-12-01

    A 42-year-old woman developed severe, recurrent breast abscesses caused by Corynebacterium minutissimum. Prior reports of C. minutissimum infection have been limited to erythrasma, a minor dermatosis. The microbiological and clinical features of this species were reviewed. PMID:6520230

  14. Feature-Based Attention and Feature-Based Expectation.

    PubMed

    Summerfield, Christopher; Egner, Tobias

    2016-06-01

    Foreknowledge of target stimulus features improves visual search performance as a result of 'feature-based attention' (FBA). Recent studies have reported that 'feature-based expectation' (FBE) also heightens decision sensitivity. Superficially, it appears that the latter work has simply rediscovered (and relabeled) the effects of FBA. However, this is not the case. Here we explain why. PMID:27079632

  15. Extremely high-dimensional feature selection via feature generating samplings.

    PubMed

    Li, Shutao; Wei, Dan

    2014-06-01

    To select informative features on extremely high-dimensional problems, in this paper, a sampling scheme is proposed to enhance the efficiency of recently developed feature generating machines (FGMs). Note that in FGMs O(mlogr) time complexity should be taken to order the features by their scores; the entire computational cost of feature ordering will become unbearable when m is very large, for example, m > 10(11) , where m is the feature dimensionality and r is the size of the selected feature subset. To solve this problem, in this paper, we propose a feature generating sampling method, which can reduce this computational complexity to O(Gslog(G)+G(G+log(G))) while preserving the most informative features in a feature buffer, where Gs is the maximum number of nonzero features for each instance and G is the buffer size. Moreover, we show that our proposed sampling scheme can be deemed as the birth-death process based on random processes theory, which guarantees to include most of the informative features for feature selections. Empirical studies on real-world datasets show the effectiveness of the proposed sampling method. PMID:23864272

  16. What Causes Angina?

    MedlinePlus

    ... blocks the arteries, reducing blood flow to the heart muscle. Some plaque is hard and stable and causes the arteries ... This can greatly reduce blood flow to the heart and cause angina. Other plaque is soft and more likely to rupture (break ...

  17. What Causes Bad Breath?

    MedlinePlus

    ... I Help a Friend Who Cuts? What Causes Bad Breath? KidsHealth > For Teens > What Causes Bad Breath? Print A A A Text Size en ... Qué es lo que provoca el mal aliento? Bad breath, or halitosis , can be a major problem, ...

  18. The amplification of environmental noise in population models: causes and consequences.

    PubMed

    Greenman, J V; Benton, T G

    2003-02-01

    Environmental variability is a ubiquitous feature of every organism's habitat. However, the interaction between density dependence and those density-independent factors that are manifested as environmental noise is poorly understood. We are interested in the conditions under which noise interacts with the density dependence to cause amplification of that noise when filtered by the system. For a broad family of structured population models, we show that amplification occurs near the threshold from stable to unstable dynamics by deriving an analytic formula for the amplification under weak noise. We confirm that the effect of noise is to sustain oscillations that would otherwise decay, and we show that it is the amplitude and not the phase that is affected. This is a feature noted in several recent studies. We study this phenomenon in detail for the lurchin and LPA models of population dynamics. We find that the degree of amplification is sensitive to both the noise input and life-history stage through which it acts, that the results hold for surprisingly high levels of noise, and that stochastic chaos (as measured by local Lyapunov exponents) is a concomitant feature of amplification. Further, it is shown that the temporal autocorrelation, or "color," of the noise has a major impact on the system response. We discuss the conditions under which color increases population variance and hence the risk of extinction, and we show that periodicity is sharpened when the color of the noise and dynamics coincide. Otherwise, there is interference, which shows how difficult it is in practice to separate the effects of nonlinearity and noise in short time series. The sensitivity of the population dynamics to noise when close to a bifurcation has wide-ranging consequences for the evolution and ecology of population dynamics. PMID:12675369

  19. Geographic comparison of selected large-scale planetary surface features

    SciTech Connect

    Meszaros, S.P.

    1984-08-01

    Photographic and cartographic comparisons of geographic features on Mercury, the Moon, Earth, Mars, Ganymede, Callisto, Mimas, and Tethys are presented. Planetary structures caused by impacts, volcanism, tectonics, and other natural forces are included. Each feature is discussed individually and then those of similar origin are compared at the same scale.

  20. Drawing on Text Features for Reading Comprehension and Composing

    ERIC Educational Resources Information Center

    Risko, Victoria J.; Walker-Dalhouse, Doris

    2011-01-01

    Students read multiple-genre texts such as graphic novels, poetry, brochures, digitized texts with videos, and informational and narrative texts. Features such as overlapping illustrations and implied cause-and-effect relationships can affect students' comprehension. Teaching with these texts and drawing attention to organizational features hold…

  1. Salient features of solitary waves in dusty plasma under the influence of Coriolis force

    SciTech Connect

    Das, G. C.; Nag, Apratim

    2007-08-15

    The main interest is to study the nonlinear acoustic wave in rotating dusty plasma augmented through the derivation of a modified Sagdeev potential equation. Small rotation causes the interaction of Coriolis force in the dynamical system, and leads to the complexity in the derivation of the nonlinear wave equation. As a result, the finding of solitary wave propagation in dusty plasma ought to be of merit. However, the nonlinear wave equation has been successfully solved by the use of the hyperbolic method. Main emphasis has been given to the changes on the evolution and propagation of soliton, and the variation caused by the dusty plasma constituents as well as by the Coriolis force have been highlighted. Some interesting nonlinear wave behavior has been found which can be elaborately studied for the interest of laboratory and space plasmas. Further, to support the theoretical investigations, numeric plasma parameters have been taken for finding the inherent features of solitons.

  2. Pynamic: the Python Dynamic Benchmark

    SciTech Connect

    Lee, G L; Ahn, D H; de Supinksi, B R; Gyllenhaal, J C; Miller, P J

    2007-07-10

    Python is widely used in scientific computing to facilitate application development and to support features such as computational steering. Making full use of some of Python's popular features, which improve programmer productivity, leads to applications that access extremely high numbers of dynamically linked libraries (DLLs). As a result, some important Python-based applications severely stress a system's dynamic linking and loading capabilities and also cause significant difficulties for most development environment tools, such as debuggers. Furthermore, using the Python paradigm for large scale MPI-based applications can create significant file IO and further stress tools and operating systems. In this paper, we present Pynamic, the first benchmark program to support configurable emulation of a wide-range of the DLL usage of Python-based applications for large scale systems. Pynamic has already accurately reproduced system software and tool issues encountered by important large Python-based scientific applications on our supercomputers. Pynamic provided insight for our system software and tool vendors, and our application developers, into the impact of several design decisions. As we describe the Pynamic benchmark, we will highlight some of the issues discovered in our large scale system software and tools using Pynamic.

  3. Occupational respiratory disease caused by acrylates.

    PubMed

    Savonius, B; Keskinen, H; Tuppurainen, M; Kanerva, L

    1993-05-01

    Acrylates are compounds used in a variety of industrial fields and their use is increasing. They have many features which make them superior to formerly used chemicals, regarding both their industrial use and their possible health effects. Contact sensitization is, however, one of their well known adverse health effects but they may also cause respiratory symptoms. We report on 18 cases of respiratory disease, mainly asthma, caused by different acrylates, 10 cases caused by cyanoacrylates, four by methacrylates and two cases by other acrylates. PMID:8334539

  4. Modelling the mechanoreceptor’s dynamic behaviour

    PubMed Central

    Song, Zhuoyi; Banks, Robert W; Bewick, Guy S

    2015-01-01

    All sensory receptors adapt, i.e. they constantly adjust their sensitivity to external stimuli to match the current demands of the natural environment. Electrophysiological responses of sensory receptors from widely different modalities seem to exhibit common features related to adaptation, and these features can be used to examine the underlying sensory transduction mechanisms. Among the principal senses, mechanosensation remains the least understood at the cellular level. To gain greater insights into mechanosensory signalling, we investigated if mechanosensation displayed adaptive dynamics that could be explained by similar biophysical mechanisms in other sensory modalities. To do this, we adapted a fly photoreceptor model to describe the primary transduction process for a stretch-sensitive mechanoreceptor, taking into account the viscoelastic properties of the accessory muscle fibres and the biophysical properties of known mechanosensitive channels (MSCs). The model’s output is in remarkable agreement with the electrical properties of a primary ending in an isolated decapsulated spindle; ramp-and-hold stretch evokes a characteristic pattern of potential change, consisting of a large dynamic depolarization during the ramp phase and a smaller static depolarization during the hold phase. The initial dynamic component is likely to be caused by a combination of the mechanical properties of the muscle fibres and a refractory state in the MSCs. Consistent with the literature, the current model predicts that the dynamic component is due to a rapid stress increase during the ramp. More novel predictions from the model are the mechanisms to explain the initial peak in the dynamic component. At the onset of the ramp, all MSCs are sensitive to external stimuli, but as they become refractory (inactivated), fewer MSCs are able to respond to the continuous stretch, causing a sharp decrease after the peak response. The same mechanism could contribute a faster component in

  5. Genetic Features of Turner Syndrome

    MedlinePlus

    ... Current Studies Publications Lab Staff Contact Info Links Genetic Features Quick Navigation Introduction X-monosomy X-mosaicism ... Figure 3. X Chromosome Abnormalities Figure 4. Mosaicism Genetic Features of Turner Syndrome Turner syndrome is a ...

  6. Hydrate pingoes at Nyegga: some characteristic features

    NASA Astrophysics Data System (ADS)

    Hovland, M.

    2009-04-01

    Hydrate pingoes were observed on the seafloor during two different remotely operated vehicle (ROV)-dives, conducted by Statoil at complex-pockmark G11, at Nyegga, off Mid-Norway. Confirmation that these structures actually represent hydrate ice-cored sediment mounds (pingoes), was done by other investigators (Ivanov et al., 2006). Because it is expected that hydrate pingoes represent relatively dynamic seafloor topographic structures and that their shape and size most probably will change over relatively short time, it is important to know how to recognise them visually. Hovland and Svensen (2006) highlighted five different characteristic aspects that define hydrate pingoes on the sea floor: 1) They are dome- or disc-shaped features, which may attain any size from ~0.5 m in height and upwards. Inside pockmark G11, they were up to 1 m high. 2) They are circular or oval in plan view and may attain lateral sizes on the seafloor ranging upwards from ~0.5 m. Inside G11 they had lengths of several metres and widths of up to 4 m. 3) They have dense communities of organisms growing on their surfaces. At G11, they were overgrown with small pogonophoran tube-worms. 4) They have patches of white or grey bacterial mats growing on their surface, indicating advection (seepage) of reduced pore-waters. 5) They have small pits and patches of fluidized sediments on their surface, indicating pit corrosion of the sub-surface gas hydrate. Because gas hydrates often form in high-porosity, near-surface sediments, where water is readily available, it is thought that they will build up at locations where gases are actively migrating upwards from depth. However, gas hydrates are not stable in the presence of ambient seawater, as seawater is deficient in guest molecule gases (normally methane). Therefore, they tend to build up below surface above conduits for gas flow from depth. But, the near-surface hydrate ice-lenses will continually be corroded by seawater circulating into the sediments

  7. Feature space discriminant analysis for hyperspectral data feature reduction

    NASA Astrophysics Data System (ADS)

    Imani, Maryam; Ghassemian, Hassan

    2015-04-01

    Hyperspectral images contain a large number of spectral bands that allows us to distinguish different classes with more details. But, the number of available training samples is limited. Thus, feature reduction is an important step before classification of high dimensional data. Supervised feature extraction methods such as LDA, GDA, NWFE, and MMLDA use two criteria for feature reduction: between-class scatter and within-class scatter. We propose a supervised feature extraction method in this paper that uses a new criterion in addition to two mentioned measures. The proposed method, which is called feature space discriminant analysis (FSDA), at first, maximizes the between-spectral scatter matrix to increase the difference between extracted features. In the second step, FSDA, maximizes the between-class scatter matrix and minimizes the within-class scatter matrix simultaneously. The experimental results on five popular hyperspectral images show the better performance of FSDA in comparison with other supervised feature extraction methods in small sample size situation.

  8. Clinical features of actinomycosis

    PubMed Central

    Bonnefond, Simon; Catroux, Mélanie; Melenotte, Cléa; Karkowski, Ludovic; Rolland, Ludivine; Trouillier, Sébastien; Raffray, Loic

    2016-01-01

    Abstract Actinomycosis is a rare heterogeneous anaerobic infection with misleading clinical presentations that delay diagnosis. A significant number of misdiagnosed cases have been reported in specific localizations, but studies including various forms of actinomycosis have rarely been published. We performed a multicenter retrospective chart review of laboratory-confirmed actinomycosis cases from January 2000 until January 2014. We described clinical characteristics, diagnostic procedures, differential diagnosis, and management of actinomycosis of clinical significance. Twenty-eight patients were included from 6 hospitals in France. Disease was diagnosed predominately in the abdomen/pelvis (n = 9), orocervicofacial (n = 5), cardiothoracic (n = 5), skeletal (n = 3), hematogenous (n = 3), soft tissue (n = 2), and intracranially (n = 1). Four patients (14%) were immunocompromised. In most cases (92 %), the diagnosis of actinomycosis was not suspected on admission, as clinical features were not specific. Diagnosis was obtained from either microbiology (50%, n = 14) or histopathology (42%, n = 12), or from both methods (7%, n = 2). Surgical biopsy was needed for definite diagnosis in 71% of cases (n = 20). Coinfection was found in 13 patients (46%), among which 3 patients were diagnosed from histologic criteria only. Two-thirds of patients were treated with amoxicillin. Median duration of antibiotics was 120 days (interquartile range 60–180), whereas the median follow-up time was 12 months (interquartile range 5.25–18). Two patients died. This study highlights the distinct and miscellaneous patterns of actinomycosis to prompt accurate diagnosis and earlier treatments, thus improving the outcome. Surgical biopsy should be performed when possible while raising histologist's and microbiologist's awareness of possible actinomycosis to enhance the chance of diagnosis and use specific molecular methods. PMID:27311002

  9. Slim Battery Modelling Features

    NASA Astrophysics Data System (ADS)

    Borthomieu, Y.; Prevot, D.

    2011-10-01

    Saft has developed a life prediction model for VES and MPS cells and batteries. The Saft Li-ion Model (SLIM) is a macroscopic electrochemical model based on energy (global at cell level). The main purpose is to predict the battery performances during the life for GEO, MEO and LEO missions. This model is based on electrochemical characteristics such as Energy, Capacity, EMF, Internal resistance, end of charge voltage. It uses fading and calendar law effects on energy and internal impedance vs. time, temperature, End of Charge voltage. Based on the mission profile, satellite power system characteristics, the model proposes the various battery configurations. For each configuration, the model gives the battery performances using mission figures and profiles: power, duration, DOD, end of charge voltages, temperatures during eclipses and solstices, thermal dissipations and cell failures. For the GEO/MEO missions, eclipse and solstice periods can include specific profile such as plasmic propulsion fires and specific balancing operations. For LEO missions, the model is able to simulate high power peaks to predict radar pulses. Saft's main customers have been using the SLIM model available in house for two years. The purpose is to have the satellite builder power engineers able to perform by themselves in the battery pre-dimensioning activities their own battery simulations. The simulations can be shared with Saft engineers to refine the power system designs. This model has been correlated with existing life and calendar tests performed on all the VES and MPS cells. In comparing with more than 10 year lasting life tests, the accuracy of the model from a voltage point of view is less than 10 mV at end Of Life. In addition, thethe comparison with in-orbit data has been also done. b This paper wi