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Sample records for change tipping points

  1. Tipping Point

    Medline Plus

    Full Text Available ... en español Blog About OnSafety CPSC Stands for Safety The Tipping Point Home > 60 Seconds of Safety (Videos) > The Tipping Point The Tipping Point by ... danger death electrical fall furniture head injury product safety television tipover tv Watch the video in Adobe ...

  2. Arctic Climate Tipping Points

    OpenAIRE

    Lenton, Timothy M.

    2012-01-01

    There is widespread concern that anthropogenic global warming will trigger Arctic climate tipping points. The Arctic has a long history of natural, abrupt climate changes, which together with current observations and model projections, can help us to identify which parts of the Arctic climate system might pass future tipping points. Here the climate tipping points are defined, noting that not all of them involve bifurcations leading to irreversible change. Past abrupt climate changes in the A...

  3. Tipping Points in Texas Rivers

    Science.gov (United States)

    Phillips, Jonathan

    2016-04-01

    Anticipating geomorphic tipping points requires that we learn from the past. Major geomorphic changes in coastal plain rivers of Texas resulting in river metamorphosis or regime shifts were identified, and the major driving factors determined. Nine fluvial tipping points were identified from contemporary observations, historical records, and Quaternary reconstructions. Two of the tipping points (between general aggrading and degrading valley states) are associated with reversals in a fundamental system control (sea-level). One (stable or aggrading vs. degrading channels) is associated with an abrupt change in sediment supply due to dam construction, and two others (changes from meandering to anastomosing channel patterns, and different anastomosis styles) are similarly related to changes in sediment supply and/or transport capacity, but with additional elements of historical contingency. Three tipping points are related to avulsions. One, from a regime dominated to reoccupation of former channels to one dominated by progradation into flood basins, is driven by progressive long term filling of incised valleys. Another, nodal avulsions, are driven by disturbances associated with tectonics or listric faults. The third, avulsions and related valley metamorphosis in unfilled incised valleys, is due to fundamental dynamical instabilities within the fluvial system. This synthesis and analysis suggests that geomorphic tipping points are sometimes associated with general extrinsic or intrinsic (to the fluvial system) environmental change, independent of any disturbances or instabilities. Others are associated with natural (e.g., tectonic) or human (dams) disturbances, and still others with intrinsic geomorphic instabilities. This suggests that future tipping points will be equally diverse with respect to their drivers.

  4. Towards a tipping point in responding to change: rising costs, fewer options for Arctic and global societies.

    Science.gov (United States)

    Huntington, Henry P; Goodstein, Eban; Euskirchen, Eugénie

    2012-02-01

    Climate change incurs costs, but government adaptation budgets are limited. Beyond a certain point, individuals must bear the costs or adapt to new circumstances, creating political-economic tipping points that we explore in three examples. First, many Alaska Native villages are threatened by erosion, but relocation is expensive. To date, critically threatened villages have not yet been relocated, suggesting that we may already have reached a political-economic tipping point. Second, forest fires shape landscape and ecological characteristics in interior Alaska. Climate-driven changes in fire regime require increased fire-fighting resources to maintain current patterns of vegetation and land use, but these resources appear to be less and less available, indicating an approaching tipping point. Third, rapid sea level rise, for example from accelerated melting of the Greenland ice sheet, will create a choice between protection and abandonment for coastal regions throughout the world, a potential global tipping point comparable to those now faced by Arctic communities. The examples illustrate the basic idea that if costs of response increase more quickly than available resources, then society has fewer and fewer options as time passes. PMID:22270706

  5. Evolutionary tipping points in the capacity to adapt to environmental change

    NARCIS (Netherlands)

    Botero, Carlos A.; Weissing, Franz J.; Wright, Jonathan; Rubenstein, Dustin R.

    2015-01-01

    In an era of rapid climate change, there is a pressing need to understand how organisms will cope with faster and less predictable variation in environmental conditions. Here we develop a unifying model that predicts evolutionary responses to environmentally driven fluctuating selection and use this

  6. Social tipping points and Earth systems dynamics

    OpenAIRE

    Bentley, R. A.; Maddison, Eleanor J.; Ranner, P. H.; Bissell, John; Caiado, Camila C. S.; Bhatanacharoen, Pojanath; Clark, Timothy; Botha, Marc; Akinbami, Folarin; Hollow, Matthew; Michie, Ranald; Huntley, Brian; Curtis, Sarah E; Garnett, Philip

    2014-01-01

    Recently, Early Warning Signals (EWS) have been developed to predict tipping points in Earth Systems. This discussion highlights the potential to apply EWS to human social and economic systems, which may also undergo similar critical transitions. Social tipping points are particularly difficult to predict, however, and the current formulation of EWS, based on a physical system analogy, may be insufficient. As an alternative set of EWS for social systems, we join with other auth...

  7. The Tipping Points of Technology Development

    Directory of Open Access Journals (Sweden)

    Tauno Kekäle

    2014-07-01

    Full Text Available The tipping point, the decisive point in time in the competition between old and new, is an interesting phenomenon in physics of today. This aspect in technology acceptance is connected to many business decisions such as technology investments, product releases, resource allocation, sales forecasts and, ultimately, affects the profitability and even survival of a company. The tipping point itself is based on many stochastic and dynamic variables, and the process may at least partly be described as path-dependent. This paper analyses the tipping point from three aspects: (1 product performance, (2 features of the market and infrastructure (including related technologies and human network externalities, and (3 actions of the incumbents (including customer lock-in, systems lock-in, and sustaining innovation. The paper is based on the Bass s-curve idea and the technology trajectory concept proposed by Dosi. Three illustrative cases are presented to make the point of the multiple factors affecting technology acceptance and, thus, the tipping point. The paper also suggests outlines for further research in field of computer simulation.

  8. Using adaptation tipping points to prepare for climate change and sea level rise: a case study in the Netherlands

    NARCIS (Netherlands)

    Kwadijk, J.C.J.; Haasnoot, M.; Mulder, J.P.M.; Hoogvliet, M.; Jeuken, A.; Krogt, R. van de; Oostrom, N. van; Schelfhout, H.; Velzen, H. van; Waveren, H. van; Wit, M.J.M. de

    2010-01-01

    Studies on the impact of climate change and sea level rise usually take climate scenarios as their starting point. To support long-termwater management planning in the Netherlands, we carried out a study that started at the opposite end of the effect chain. In the study we refer to three aspects of

  9. Tipping points in Anthropocene fluvial dynamics

    Science.gov (United States)

    Notebaert, Bastiaan; Broothaerts, Nils; Verstraeten, Gert; Berger, Jean-François; Houbrechts, Geoffrey

    2016-04-01

    the river partially maintains its braided pattern. The Amblève River in the Belgian Ardennes uplands underwent less dramatic changes. Large parts of the catchment are deforested during the last 700 years, leading to an increase in floodplain sedimentation. Despite this major sediment pulse, change in floodplain morphology remained limited to an increase in bank height. We argue that a combination of floodplain and channel morphology, the fine texture of supplied sediment and the high stream power of channel forming events result is a system that is less sensitive to change. Also the relative short time of impact may play a role. These three examples demonstrate the varying impact of human deforestation on floodplain geomorphology. For the Dijle and Valdaine region this lead to dramatic changes once a certain tipping point is reached. In contrast the Amblève river is more resilient to human impact due to its specific morphological setting. The morphology of the catchments and the nature of supplied sediments plays a major role in the sensitivity of fluvial systems to environmental impact. Once the tipping points are reached, it is difficult for the river to revert to its original state and floodplains remain highly impacted.

  10. Quaternary Tipping Points in Tropical Northern Australia

    Science.gov (United States)

    Moss, Patrick; Dunbar, Gavin; Croke, Jacky; Katunar, Rosie

    2016-04-01

    Tropical northern Queensland, particularly the volcanic Atherton Tableland, contains some of the most detailed and longest terrestrial palaeoenvironmental archives in Australia and when combined with adjacent marine sediment records provides key insight into potential environmental 'tipping points' for the entire Quaternary period and beyond. This presentation will provide an overview of some of the key tipping points (i.e. significant landscape transformation) that have occurred within the tropical northern Australian region over the Quaternary, as well as discussing potential causes and subsequent impacts of these transformation episodes. These events include the development of the Great Barrier Reef, transition from obliquity to eccentricity dominated glacial-interglacial cycles, the Mid-Brunhes event, the Oxygen Isotope Stage 6 episode, the arrival of people into the region, Last Glacial-Interglacial Transition and European settlement.

  11. Tipping point analysis of atmospheric oxygen concentration

    Energy Technology Data Exchange (ETDEWEB)

    Livina, V. N.; Forbes, A. B. [National Physical Laboratory, Teddington TW11 0LW (United Kingdom); Vaz Martins, T. M. [John Innes Centre, Norwich NR4 7UH (United Kingdom)

    2015-03-15

    We apply tipping point analysis to nine observational oxygen concentration records around the globe, analyse their dynamics and perform projections under possible future scenarios, leading to oxygen deficiency in the atmosphere. The analysis is based on statistical physics framework with stochastic modelling, where we represent the observed data as a composition of deterministic and stochastic components estimated from the observed data using Bayesian and wavelet techniques.

  12. Trapping Phenomenon Attenuates Tipping Points for Limit Cycles

    CERN Document Server

    Medeiros, Everton S; Baptista, Murilo S; Feudel, Ulrike

    2016-01-01

    Nonlinear dynamical systems may be exposed to tipping points, critical thresholds at which small changes in the external inputs or in the systems parameters abruptly shift the system to an alternative state with a contrasting dynamical behavior. While tipping in a fold bifurcation of an equilibrium is well understood, much less is known about tipping of oscillations (limit cycles) though this dynamics are the typical response of many natural systems to a periodic external forcing, like e.g. seasonal forcing in ecology and climate sciences. We provide a detailed analysis of tipping phenomena in periodically forced systems and show that, when limit cycles are considered, a transient structure, so-called channel, plays a fundamental role in the transition. Specifically, we demonstrate that trajectories crossing such channel conserve, for a characteristic time, the twisting behavior of the stable limit cycle destroyed in the fold bifurcation of cycles. As a consequence, this channel acts like a ghost of the limit...

  13. Detecting tipping points in ecological models with sensitivity analysis

    NARCIS (Netherlands)

    Broeke, G.A. ten; Voorn, van G.A.K.; Kooi, B.W.; Molenaar, J.

    2016-01-01

    Simulation models are commonly used to understand and predict the developmentof ecological systems, for instance to study the occurrence of tipping points and their possibleecological effects. Sensitivity analysis is a key tool in the study of model responses to change s in conditions. The applicabi

  14. Detecting Tipping points in Ecological Models with Sensitivity Analysis

    NARCIS (Netherlands)

    Broeke, ten G.A.; Voorn, van G.A.K.; Kooi, B.W.; Molenaar, Jaap

    2016-01-01

    Simulation models are commonly used to understand and predict the development of ecological systems, for instance to study the occurrence of tipping points and their possible ecological effects. Sensitivity analysis is a key tool in the study of model responses to changes in conditions. The appli

  15. Geomorphic tipping points: convenient metaphor or fundamental landscape property?

    Science.gov (United States)

    Lane, Stuart

    2016-04-01

    In 2000 Malcolm Gladwell published as book that has done much to publicise Tipping Points in society but also in academia. His arguments, re-expressed in a geomorphic sense, have three core elements: (1) a "Law of the Few", where rapid change results from the effects of a relatively restricted number of critical elements, ones that are able to rapidly connect systems together, that are particularly sensitive to an external force, of that are spatially organised in a particular way; (2) a "Stickiness" where an element of the landscape is able to assimilate characteristics which make it progressively more applicable to the "Law of the Few"; and (3), given (1) and (2) a history and a geography that means that the same force can have dramatically different effects, according to where and when it occurs. Expressed in this way, it is not clear that Tipping Points bring much to our understanding in geomorphology that existing concepts (e.g. landscape sensitivity and recovery; cusp-catastrophe theory; non-linear dynamics systems) do not already provide. It may also be all too easy to describe change in geomorphology as involving a Tipping Point: we know that geomorphic processes often involve a non-linear response above a certain critical threshold; we know that landscapes can, after Denys Brunsden, be though of as involving long periods of boredom ("stability") interspersed with brief moments of terror ("change"); but these are not, after Gladwell, sufficient for the term Tipping Point to apply. Following from these issues, this talk will address three themes. First, it will question, through reference to specific examples, notably in high Alpine systems, the extent to which the Tipping Point analogy is truly a property of the world in which we live. Second, it will explore how 'tipping points' become assigned metaphorically, sometimes evolving to the point that they themselves gain agency, that is, shaping the way we interpret landscape rather than vice versa. Third, I

  16. Light-driven tipping points in polar ecosystems.

    Science.gov (United States)

    Clark, Graeme F; Stark, Jonathan S; Johnston, Emma L; Runcie, John W; Goldsworthy, Paul M; Raymond, Ben; Riddle, Martin J

    2013-12-01

    Some ecosystems can undergo abrupt transformation in response to relatively small environmental change. Identifying imminent 'tipping points' is crucial for biodiversity conservation, particularly in the face of climate change. Here, we describe a tipping point mechanism likely to induce widespread regime shifts in polar ecosystems. Seasonal snow and ice-cover periodically block sunlight reaching polar ecosystems, but the effect of this on annual light depends critically on the timing of cover within the annual solar cycle. At high latitudes, sunlight is strongly seasonal, and ice-free days around the summer solstice receive orders of magnitude more light than those in winter. Early melt that brings the date of ice-loss closer to midsummer will cause an exponential increase in the amount of sunlight reaching some ecosystems per year. This is likely to drive ecological tipping points in which primary producers (plants and algae) flourish and out-compete dark-adapted communities. We demonstrate this principle on Antarctic shallow seabed ecosystems, which our data suggest are sensitive to small changes in the timing of sea-ice loss. Algae respond to light thresholds that are easily exceeded by a slight reduction in sea-ice duration. Earlier sea-ice loss is likely to cause extensive regime shifts in which endemic shallow-water invertebrate communities are replaced by algae, reducing coastal biodiversity and fundamentally changing ecosystem functioning. Modeling shows that recent changes in ice and snow cover have already transformed annual light budgets in large areas of the Arctic and Antarctic, and both aquatic and terrestrial ecosystems are likely to experience further significant change in light. The interaction between ice-loss and solar irradiance renders polar ecosystems acutely vulnerable to abrupt ecosystem change, as light-driven tipping points are readily breached by relatively slight shifts in the timing of snow and ice-loss. PMID:23893603

  17. Light-driven tipping points in polar ecosystems.

    Science.gov (United States)

    Clark, Graeme F; Stark, Jonathan S; Johnston, Emma L; Runcie, John W; Goldsworthy, Paul M; Raymond, Ben; Riddle, Martin J

    2013-12-01

    Some ecosystems can undergo abrupt transformation in response to relatively small environmental change. Identifying imminent 'tipping points' is crucial for biodiversity conservation, particularly in the face of climate change. Here, we describe a tipping point mechanism likely to induce widespread regime shifts in polar ecosystems. Seasonal snow and ice-cover periodically block sunlight reaching polar ecosystems, but the effect of this on annual light depends critically on the timing of cover within the annual solar cycle. At high latitudes, sunlight is strongly seasonal, and ice-free days around the summer solstice receive orders of magnitude more light than those in winter. Early melt that brings the date of ice-loss closer to midsummer will cause an exponential increase in the amount of sunlight reaching some ecosystems per year. This is likely to drive ecological tipping points in which primary producers (plants and algae) flourish and out-compete dark-adapted communities. We demonstrate this principle on Antarctic shallow seabed ecosystems, which our data suggest are sensitive to small changes in the timing of sea-ice loss. Algae respond to light thresholds that are easily exceeded by a slight reduction in sea-ice duration. Earlier sea-ice loss is likely to cause extensive regime shifts in which endemic shallow-water invertebrate communities are replaced by algae, reducing coastal biodiversity and fundamentally changing ecosystem functioning. Modeling shows that recent changes in ice and snow cover have already transformed annual light budgets in large areas of the Arctic and Antarctic, and both aquatic and terrestrial ecosystems are likely to experience further significant change in light. The interaction between ice-loss and solar irradiance renders polar ecosystems acutely vulnerable to abrupt ecosystem change, as light-driven tipping points are readily breached by relatively slight shifts in the timing of snow and ice-loss.

  18. Photovoltaics R&D: At the Tipping Point

    Energy Technology Data Exchange (ETDEWEB)

    Kazmerski, L. L.

    2005-01-01

    '' . . . with robust investments in research and market development, the picture changes dramatically.'' Thus, the realigned U.S. Photovoltaic Industry Roadmap highlights R&D as critical to the tipping point that will make solar photovoltaics (PV) significant in the U.S. energy portfolio--part of a well-designed plan that would bring ''2034 expectations'' to reality by 2020. Technology improvement and introduction depend on key, focused, and pertinent research contributions that range from the most fundamental through the applied. In this paper, we underscore the successes and relevance of our current systems-driven PV R&D programs, which are built on integrated capabilities. These capabilities span atomic-level characterization, nanotechnology, new materials design, interface and device engineering, theoretical guidance and modeling, processing, measurements and analysis, and process integration. This presentation identifies and provides examples of critical research tipping points needed to foster now and near technologies (primarily crystalline silicon and thin films) and to introduce coming generations of solar PV that provide options to push us to the next performance levels (devices with ultra-high efficiencies and with ultra-low cost). The serious importance of science and creativity to U.S. PV technology ownership--and the increased focus to accelerate the time from laboratory discovery to industry adoption--are emphasized at this ''tipping point'' for solar PV.

  19. Risk-analysis of global climate tipping points

    Energy Technology Data Exchange (ETDEWEB)

    Frieler, Katja; Meinshausen, Malte; Braun, N. [Potsdam Institute for Climate Impact Research e.V., Potsdam (Germany). PRIMAP Research Group] [and others

    2012-09-15

    There are many elements of the Earth system that are expected to change gradually with increasing global warming. Changes might prove to be reversible after global warming returns to lower levels. But there are others that have the potential of showing a threshold behavior. This means that these changes would imply a transition between qualitatively disparate states which can be triggered by only small shifts in background climate (2). These changes are often expected not to be reversible by returning to the current level of warming. The reason for that is, that many of them are characterized by self-amplifying processes that could lead to a new internally stable state which is qualitatively different from before. There are different elements of the climate system that are already identified as potential tipping elements. This group contains the mass losses of the Greenland and the West-Antarctic Ice Sheet, the decline of the Arctic summer sea ice, different monsoon systems, the degradation of coral reefs, the dieback of the Amazon rainforest, the thawing of the permafrost regions as well as the release of methane hydrates (3). Crucially, these tipping elements have regional to global scale effects on human society, biodiversity and/or ecosystem services. Several examples may have a discernable effect on global climate through a large-scale positive feedback. This means they would further amplify the human induced climate change. These tipping elements pose risks comparable to risks found in other fields of human activity: high-impact events that have at least a few percent chance to occur classify as high-risk events. In many of these examples adaptation options are limited and prevention of occurrence may be a more viable strategy. Therefore, a better understanding of the processes driving tipping points is essential. There might be other tipping elements even more critical but not yet identified. These may also lie within our socio-economic systems that are

  20. Forest resilience and tipping points at different spatio-temporal scales: approaches and challenges

    NARCIS (Netherlands)

    Reyer, C.P.O.; Brouwers, N.; Rammig, A.; Brook, B.W.; Holmgren, M.; Villela, D.M.

    2015-01-01

    1. Anthropogenic global change compromises forest resilience, with profound impacts to ecosystem functions and services. This synthesis paper reflects on the current understanding of forest resilience and potential tipping points under environmental change and explores challenges to assessing respon

  1. Crossing thresholds: Analysis of hazardous tipping points in alpine catchments

    Science.gov (United States)

    Lutzmann, Silke; Sass, Oliver

    2016-04-01

    Steep mountain channels or torrents in small alpine catchments are characterized by high geomorphic activity with sediment dynamics being inherently nonlinear and threshold-mediated. Localized, high intensity rainstorms can drive torrential systems past a tipping point resulting in a sudden onset of hazardous events like (flash-) flooding, heavy bedload transport or debris flows. Such responses exhibit an abrupt switch in the fluvial system's mode (e.g. transport / supply limited). Changes in functional connectivity may persist beyond the tipping point. Torrential hazards cause costly damage in the densely populated Alpine Region. Thus, there is a rising interest in potential effects of climate change on torrential sediment dynamics. Understanding critical conditions close to tipping points is important to reduce uncertainty in predicting sediment fluxes. In this study we aim at (i) establishing threshold precipitation characteristics for the Eastern Alps of Austria. Precipitation is hypothesized to be the main forcing factor of torrential events. (ii) How do thresholds vary in space and time? (iii) The effect of external triggers is strongly mediated by the internal disposition of catchments to respond. Which internal conditions are critical for susceptibility? (iv) Is there a change in magnitude or frequency in the recent past and what can be expected for the future? The 71 km2 catchment of the river Schöttlbach in the East Alpine Region of Styria (Austria) is monitored since a heavy precipitation event resulted in a catastrophic flood in July 2011. Sediment mobilization from slopes as well as within-channel storage and bedload transport are regularly measured using photogrammetric methods and sediment impact sensors. Thus, detailed knowledge exists on magnitude and spatial propagation of sediment waves through the catchment. The associated hydro-meteorological (pre-) conditions can be inferred from a dense station network. Changing bedload transport rates and

  2. Modelling tipping-point phenomena of scientific coauthorship networks

    CERN Document Server

    Xie, Zheng; Yi, Dongyun; Zhenzheng, Ouyang; Li, Jianping

    2016-01-01

    In a range of scientific coauthorship networks, tipping points are detected in degree distributions, correlations between degrees and local clustering coefficients, etc. The existence of those tipping points could be treated as a result of the diversity of collaboration behaviours in scientific field. A growing geometric hypergraph built on a cluster of concentric circles is proposed to model two typical collaboration behaviours, namely the behaviour of leaders and that of other members in research teams. The model successfully predicts the tipping points, as well as many common features of coauthorship networks. For example, it realizes a process of deriving the complex scale-free property from the simple yes/no experiments. Moreover, it gives a reasonable explanation for the emergence of tipping points by the difference of collaboration behaviours between leaders and other members, which emerges in the evolution of research teams. The evolution synthetically addresses typical factors of generating collabora...

  3. Energy policies avoiding a tipping point in the climate system

    Energy Technology Data Exchange (ETDEWEB)

    Bahn, Olivier [GERAD and Department of Management Sciences, HEC Montreal, Montreal (Qc) (Canada); Edwards, Neil R. [Earth and Environmental Sciences, CEPSAR, Open University, Milton Keynes MK7 6AA (United Kingdom); Knutti, Reto [Institute for Atmospheric and Climate Science, ETH Zurich, CH-8092 Zurich (Switzerland); Stocker, Thomas F. [Climate and Environmental Physics, Physics Institute, and Oeschger Centre for Climate Change Research, University of Bern, CH-3012 Bern (Switzerland)

    2011-01-15

    Paleoclimate evidence and climate models indicate that certain elements of the climate system may exhibit thresholds, with small changes in greenhouse gas emissions resulting in non-linear and potentially irreversible regime shifts with serious consequences for socio-economic systems. Such thresholds or tipping points in the climate system are likely to depend on both the magnitude and rate of change of surface warming. The collapse of the Atlantic thermohaline circulation (THC) is one example of such a threshold. To evaluate mitigation policies that curb greenhouse gas emissions to levels that prevent such a climate threshold being reached, we use the MERGE model of Manne, Mendelsohn and Richels. Depending on assumptions on climate sensitivity and technological progress, our analysis shows that preserving the THC may require a fast and strong greenhouse gas emission reduction from today's level, with transition to nuclear and/or renewable energy, possibly combined with the use of carbon capture and sequestration systems. (author)

  4. Estimating Tipping Points in Feedback-Driven Financial Networks

    Science.gov (United States)

    Kostanjcar, Zvonko; Begusic, Stjepan; Stanley, Harry Eugene; Podobnik, Boris

    2016-09-01

    Much research has been conducted arguing that tipping points at which complex systems experience phase transitions are difficult to identify. To test the existence of tipping points in financial markets, based on the alternating offer strategic model we propose a network of bargaining agents who mutually either cooperate or where the feedback mechanism between trading and price dynamics is driven by an external "hidden" variable R that quantifies the degree of market overpricing. Due to the feedback mechanism, R fluctuates and oscillates over time, and thus periods when the market is underpriced and overpriced occur repeatedly. As the market becomes overpriced, bubbles are created that ultimately burst in a market crash. The probability that the index will drop in the next year exhibits a strong hysteresis behavior from which we calculate the tipping point. The probability distribution function of R has a bimodal shape characteristic of small systems near the tipping point. By examining the S&P500 index we illustrate the applicability of the model and demonstate that the financial data exhibits a hysteresis and a tipping point that agree with the model predictions. We report a cointegration between the returns of the S&P 500 index and its intrinsic value.

  5. Tipping points in open systems: bifurcation, noise-induced and rate-dependent examples in the climate system

    CERN Document Server

    Ashwin, Peter; Vitolo, Renato; Cox, Peter

    2011-01-01

    Tipping points associated with bifurcations (B-tipping) or induced by noise (N-tipping) are recognized mechanisms that may potentially lead to sudden climate change. We focus here a novel class of tipping points, where a sufficiently rapid change to an input or parameter of a system may cause the system to "tip" or move away from a branch of attractors. Such rate-induced tipping, or {\\em R-tipping}, need not be associated with either bifurcations or noise. We present an example exhibiting all three types of tipping in a simple global energy balance model of the climate system, illustrating the possibility of dangerous rates of change even in the absence of noise and of bifurcations in the underlying quasistatic system.

  6. The tipping point how little things can make a big difference

    CERN Document Server

    Gladwell, Malcolm

    2002-01-01

    The tipping point is that magic moment when an idea, trend, or social behavior crosses a threshold, tips, and spreads like wildfire. Just as a single sick person can start an epidemic of the flu, so too can a small but precisely targeted push cause a fashion trend, the popularity of a new product, or a drop in the crime rate. This widely acclaimed bestseller, in which Malcolm Gladwell explores and brilliantly illuminates the tipping point phenomenon, is already changing the way people throughout the world think about selling products and disseminating ideas.

  7. Early warning signals of tipping points in periodically forced systems

    Science.gov (United States)

    Williamson, Mark S.; Bathiany, Sebastian; Lenton, Timothy M.

    2016-04-01

    The prospect of finding generic early warning signals of an approaching tipping point in a complex system has generated much interest recently. Existing methods are predicated on a separation of timescales between the system studied and its forcing. However, many systems, including several candidate tipping elements in the climate system, are forced periodically at a timescale comparable to their internal dynamics. Here we use alternative early warning signals of tipping points due to local bifurcations in systems subjected to periodic forcing whose timescale is similar to the period of the forcing. These systems are not in, or close to, a fixed point. Instead their steady state is described by a periodic attractor. For these systems, phase lag and amplification of the system response can provide early warning signals, based on a linear dynamics approximation. Furthermore, the Fourier spectrum of the system's time series reveals harmonics of the forcing period in the system response whose amplitude is related to how nonlinear the system's response is becoming with nonlinear effects becoming more prominent closer to a bifurcation. We apply these indicators as well as a return map analysis to a simple conceptual system and satellite observations of Arctic sea ice area, the latter conjectured to have a bifurcation type tipping point. We find no detectable signal of the Arctic sea ice approaching a local bifurcation.

  8. Feedbacks and tipping points in organismal response to oxidative stress.

    Science.gov (United States)

    Klanjscek, Tin; Muller, Erik B; Nisbet, Roger M

    2016-09-01

    Biological feedbacks play a crucial role in determining effects of toxicants, radiation, and other environmental stressors on organisms. Focusing on reactive oxygen species (ROS) that are increasingly recognized as a crucial mediator of many stressor effects, we investigate how feedback strength affects the ability of organisms to control negative effects of exposure. We do this by developing a general theoretical framework for describing effects of a wide range of stressors and species. The framework accounts for positive and negative feedbacks representing cellular processes: (i) production of ROS due to metabolism and the stressor, (ii) ROS reactions with cellular compounds that cause damage, and (iii) cellular control of both ROS and damage. We suggest functional forms that capture generic properties of cellular control mechanisms constituting the feedbacks, assess stability of equilibrium states in the resulting models, and investigate tipping points at which cellular control breaks down causing unregulated increase of ROS and damage. Depending on the chosen functional forms, the models can have zero, one, or two positive steady states; except in one singular case, the steady state with lowest values of ROS and damage is locally stable. We found two types of tipping points: those induced by changes in the parameters (including the stressor intensity), and those induced by the history of exposure, i.e. ROS and damage levels. The relatively simple models effectively describe several patterns of cellular responses to stress, such as the covariation of ROS and damage, the break-down of cellular control leading to explosion of ROS and/or damage, increase in damage even when ROS is (near)-constant, and the effects of exposure history on the ability of the cell to handle additional stress. The models quantify dynamics of cellular control, and could therefore be used to estimate the metabolic costs of stress and help integrate them into models that use energetic

  9. Does landscape diversity reduce the risk of catastrophic tipping points?

    Science.gov (United States)

    Temme, Arnaud; Baartman, Jantiene; Saco, Patricia; Nijp, Jelmer; Langston, Abigail

    2016-04-01

    Most studies about tipping points are based on computer simulations. These simulations, based on first principles of vegetation growth and competition, are not only able to explain a surprising number of vegetation patterns occurring in natural ecosystems, but they also predict shifts between multiple stable states that may be catastrophic. Initially, such studies were performed on simplistic 'non-landscapes' - flats or straight slopes. Recently, we have been able to resolve geomorphic redistribution processes more accurately, so that vegetation patterning can be simulated in more complex landscapes. Here, we present a first look into how such 'real landscapes' affect the risk of catastrophic shifts. We test the hypothesis that increasing complexity and organisation in a landscape reduce the risk of catastrophic shifts by effectively creating mini-refugia where vegetation persists over a wider range of boundary conditions such as precipitation. Depending on the extent of a study area, large complexity could even change the system from one with multiple stable states into one with only one stable state.

  10. Tipping point of a conifer forest ecosystem under severe drought

    International Nuclear Information System (INIS)

    Drought-induced tree mortality has recently received considerable attention. Questions have arisen over the necessary intensity and duration thresholds of droughts that are sufficient to trigger rapid forest declines. The values of such tipping points leading to forest declines due to drought are presently unknown. In this study, we have evaluated the potential relationship between the level of tree growth and concurrent drought conditions with data of the tree growth-related ring width index (RWI) of the two dominant conifer species (Pinus edulis and Pinus ponderosa) in the Southwestern United States (SWUS) and the meteorological drought-related standardized precipitation evapotranspiration index (SPEI). In this effort, we determined the binned averages of RWI and the 11 month SPEI within the month of July within each bin of 30 of RWI in the range of 0–3000. We found a significant correlation between the binned averages of RWI and SPEI at the regional-scale under dryer conditions. The tipping point of forest declines to drought is predicted by the regression model as SPEItp = −1.64 and RWItp = 0, that is, persistence of the water deficit (11 month) with intensity of −1.64 leading to negligible growth for the conifer species. When climate conditions are wetter, the correlation between the binned averages of RWI and SPEI is weaker which we believe is most likely due to soil water and atmospheric moisture levels no longer being the dominant factor limiting tree growth. We also illustrate a potential application of the derived tipping point (SPEItp = −1.64) through an examination of the 2002 extreme drought event in the SWUS conifer forest regions. Distinguished differences in remote-sensing based NDVI anomalies were found between the two regions partitioned by the derived tipping point. (letter)

  11. Tipping points among social learners: Tools from varied disciplines

    Institute of Scientific and Technical Information of China (English)

    R. Alexander BENTLEY; Michael J. O'BRIEN

    2012-01-01

    There is a long and rich tradition in the social sciences of using models of collective behavior in animals as jumprag-off points for the study of human behavior,including collective human behavior.Here,we come at the problem in a slightly different fashion.We ask whether models of collective human behavior have anything to offer those who study animal behavior.Our brief example of tipping points,a model first developed in the physical sciences and later used in the social sciences,suggests that the analysis of human collective behavior does indeed have considerable to offer [Current Zoology 58 (2):298-306,2012].

  12. Environmental tipping points significantly affect the cost-benefit assessment of climate policies.

    Science.gov (United States)

    Cai, Yongyang; Judd, Kenneth L; Lenton, Timothy M; Lontzek, Thomas S; Narita, Daiju

    2015-04-14

    Most current cost-benefit analyses of climate change policies suggest an optimal global climate policy that is significantly less stringent than the level required to meet the internationally agreed 2 °C target. This is partly because the sum of estimated economic damage of climate change across various sectors, such as energy use and changes in agricultural production, results in only a small economic loss or even a small economic gain in the gross world product under predicted levels of climate change. However, those cost-benefit analyses rarely take account of environmental tipping points leading to abrupt and irreversible impacts on market and nonmarket goods and services, including those provided by the climate and by ecosystems. Here we show that including environmental tipping point impacts in a stochastic dynamic integrated assessment model profoundly alters cost-benefit assessment of global climate policy. The risk of a tipping point, even if it only has nonmarket impacts, could substantially increase the present optimal carbon tax. For example, a risk of only 5% loss in nonmarket goods that occurs with a 5% annual probability at 4 °C increase of the global surface temperature causes an immediate two-thirds increase in optimal carbon tax. If the tipping point also has a 5% impact on market goods, the optimal carbon tax increases by more than a factor of 3. Hence existing cost-benefit assessments of global climate policy may be significantly underestimating the needs for controlling climate change. PMID:25825719

  13. A new drought tipping point for conifer mortality

    Science.gov (United States)

    Kolb, Thomas E.

    2015-03-01

    (Huang et al 2015 Environ. Res. Lett. 10 024011) present a method for predicting mortality of ponderosa pine (Pinus ponderosa) and pinyon pine (Pinus edulis) in the Southwestern US during severe drought based on the relationship between the standardized precipitation-evapotranspiration index (SPEI) and annual tree ring growth. Ring growth was zero when SPEI for September to July was -1.64. The threshold SPEI of -1.64 was successful in distinguishing areas with high tree mortality during recent severe drought from areas with low mortality, and is proposed to be a tipping point of drought severity leading to tree mortality. Below, I discuss this work in more detail.

  14. The conscious city II: traffic congestion and the tipping point in greater Vancouver

    OpenAIRE

    Holt, Rebecca

    2007-01-01

    The Conscious City II explores how broad, long-term change toward sustainability in cities can be fostered, nurtured and facilitated. Using a qualitative, mixed-method approach, this research adapts a model from Malcolm Gladwell’s Tipping Point framework to explore how social consciousness can be mobilized to achieve change toward sustainability through an analysis of traffic congestion in Greater Vancouver. The results demonstrate the important influence of leadership, context and message on...

  15. Migraine strikes as neuronal excitability reaches a tipping point.

    Directory of Open Access Journals (Sweden)

    Marten Scheffer

    Full Text Available Self-propagating waves of cerebral neuronal firing, known as spreading depolarisations, are believed to be at the roots of migraine attacks. We propose that the start of spreading depolarisations corresponds to a critical transition that occurs when dynamic brain networks approach a tipping point. We show that this hypothesis is consistent with current pathogenetic insights and observed dynamics. Our view implies that migraine strikes when modulating factors further raise the neuronal excitability in genetically predisposed subjects to a level where even minor perturbations can trigger spreading depolarisations. A corollary is that recently discovered generic early warning indicators for critical transitions may be used to predict the onset of migraine attacks even before patients are clinically aware. This opens up new avenues for dissecting the mechanisms for the onset of migraine attacks and for identifying novel prophylactic treatment targets for the prevention of attacks.

  16. The quantum change point

    CERN Document Server

    Sentís, Gael; Calsamiglia, John; Chiribella, Giulio; Munoz-Tapia, Ramon

    2016-01-01

    Sudden changes are ubiquitous in nature. Identifying them is of crucial importance for a number of applications in medicine, biology, geophysics, and social sciences. Here we investigate the problem in the quantum domain, considering a source that emits particles in a default state, until a point where it switches to another state. Given a sequence of particles emitted by the source, the problem is to find out where the change occurred. For large sequences, we obtain an analytical expression for the maximum probability of correctly identifying the change point when joint measurements on the whole sequence are allowed. We also construct strategies that measure the particles individually and provide an online answer as soon as a new particle is emitted by the source. We show that these strategies substantially underperform the optimal strategy, indicating that quantum sudden changes, although happening locally, are better detected globally.

  17. Optimal LGS pointing with faint tip-tilt NGS

    OpenAIRE

    Dekany, Richard

    2010-01-01

    Experience with the current generation of astronomical single laser guide star (LGS) adaptive optics (AO) systems has demonstrated system performance that is often limited by residual tip-tilt errors induced by the paucity of bright tip-tilt natural guide stars (NGS). To overcome this limitation, we are developing a new generation of tip-tilt sensors that will operate at near-infrared wavelengths where the NGS is sharpened to the diffraction limit. To optimize performance, single LGS AO syste...

  18. Tipping points for seawater intrusion in coastal aquifers under rising sea level

    International Nuclear Information System (INIS)

    This study considers different projections of climate-driven sea-level rise and uses a recently developed, generalized analytical model to investigate the responses of sea intrusion in unconfined sloping coastal aquifers to climate-driven sea-level rise. The results show high nonlinearity in these responses, implying important thresholds, or tipping points, beyond which the responses of seawater intrusion to sea-level rise shift abruptly from a stable state of mild change responses to a new stable state of large responses to small changes that can rapidly lead to full seawater intrusion into a coastal aquifer. The identified tipping points are of three types: (a) spatial, for the particular aquifers (sections) along a coastline with depths that imply critical risk of full sea intrusion in response to even small sea-level rise; (b) temporal, for the critical sea-level rise and its timing, beyond which the change responses and the risk of complete sea intrusion in an aquifer shift abruptly from low to very high; and (c) managerial, for the critical minimum values of groundwater discharge and hydraulic head that inland water management must maintain in an aquifer in order to avoid rapid loss of control and complete sea intrusion in response to even small sea-level rise. The existence of a tipping point depends on highly variable aquifer properties and groundwater conditions, in combination with more homogeneous sea conditions. The generalized analytical model used in this study facilitates parsimonious quantification and screening of sea-intrusion risks and tipping points under such spatio-temporally different condition combinations along extended coastlines. (letter)

  19. Cultural evolutionary tipping points in the storage and transmission of information

    Directory of Open Access Journals (Sweden)

    R. Alexander Bentley

    2012-12-01

    Full Text Available Human culture has evolved through a series of major tipping points in information storage and communication. The first was the appearance of language, which enabled communication between brains and allowed humans to specialize in what they do and to participate in complex mating games. The second was information storage outside the brain, most obviously expressed in the Upper Paleolithic Revolution—the sudden proliferation of cave art, personal adornment, and ritual in Europe some 35,000–45,000 years ago. More recently, this storage has taken the form of writing, mass media, and now the Internet, which is arguably overwhelming humans’ ability to discern relevant information. The third tipping point was the appearance of technology capable of accumulating and manipulating vast amounts of information outside humans, thus removing them as bottlenecks to a seemingly self-perpetuating process of knowledge explosion. Important components of any discussion of cultural evolutionary tipping points are tempo and mode, given that the rate of change, as well as the kind of change, in information storage and transmission has not been constant over the previous million years.

  20. Tipping Points in 1-Dimensional Schelling Models with Switching Agents

    Science.gov (United States)

    Barmpalias, George; Elwes, Richard; Lewis-Pye, Andy

    2015-02-01

    Schelling's spacial proximity model was an early agent-based model, illustrating how ethnic segregation can emerge, unwanted, from the actions of citizens acting according to individual local preferences. Here a 1-dimensional unperturbed variant is studied under switching agent dynamics, interpretable as being open in that agents may enter and exit the model. Following the authors' work (Barmpalias et al., FOCS, 2014) and that of Brandt et al. (Proceedings of the 44th ACM Symposium on Theory of Computing (STOC 2012), 2012), rigorous asymptotic results are established. The dynamic allows either type to take over almost everywhere. Tipping points are identified between the regions of takeover and staticity. In a generalization of the models considered in [1] and [3], the model's parameters comprise the initial proportions of the two types, along with independent values of the tolerance for each type. This model comprises a 1-dimensional spin-1 model with spin dependent external field, as well as providing an example of cascading behaviour within a network.

  1. Post-TIPS change of esophagogastric variceal size on endoscopy

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Yong Joo; Park, Aw Hwan; Kang, Duk Sik [School of Medicine, Kyungpook National University, Taegu (Korea, Republic of); Shin, Hyun Woong [Andong General Hospital, Andong (Korea, Republic of)

    2000-05-01

    To evaluate the relationship between endoscopic change in esophagogastric varices and post transjugular intrahepatic portosystemic shunt (TIPS) portal pressure reduction, and to study any difference in post-TIPS endoscopic change between esophageal and gastric varices. Sixty four patients who had undergone pre- and post-TIPS endoscopic examination were analysed. They were divided into two groups, Group 1 (n=3D40) and Group 2 (n=3D24), according to whether they had not or had, respectively, undergone post-TIPS residual variceal embolization. The varices were classified as either esophageal (n=3D54) or gastric (n=3D60). Post TIPS endoscopic change was evaluated as Grade 1 (complete disappearance), Grade 2 (partial disappearance), or Grade 3 (no change). Mean pressure reduction between the pre and post TIPS portosystemic pressure gradient was checked, and statistical correlation between mean portal pressure reduction and endoscopic change in Group 1 and Group 2 was evaluated using the ANOVA test. By means of the X{sup 2} test, post-TIPS endoscopic change between esophageal and gastric varices was also evaluated. In Group 1, a significant statistical relationship was found between endoscopic change and mean portal pressure reduction (p less than 0.001), but in Group 2, no such relationship was found (p greater than 0.05). No significant statistical difference was found between endoscopic change in esophageal and in gastric varices (p greater than 0.05). In patients who had not undergone post-TIPS residual variceal embolization, endoscopic change in gastroesophageal varices correlated significantly with post-TIPS portal pressure reduction. With regard to post-TIPS endoscopic change, these was no significant difference between esophageal and gastric varices. (author)

  2. Social consensus and tipping points with opinion inertia

    CERN Document Server

    Doyle, C; Szymanski, B K; Korniss, G

    2014-01-01

    When opinions, behaviors or ideas diffuse within a population, some are invariably stickier than others. The stickier the opinion, behavior or idea, the greater is an individual's inertia to replace it with an alternative. Here we study the effect of stickiness of opinions in a two-opinion model, where individuals change their opinion only after a certain number of consecutive encounters with the alternative opinion. Assuming that one opinion has a fixed stickiness, we investigate how the critical size of the competing opinion required to tip over the entire population varies as a function of the competing opinion's stickiness. We analyze this scenario for the case of a complete-graph topology through simulations, and through a semi-analytical approach which yields an upper bound for the critical minority size. We present analogous simulation results for the case of the Erd\\H{o}s-R\\'enyi random network. Finally, we investigate the coarsening properties of sticky opinion spreading on two-dimensional lattices, ...

  3. Social consensus and tipping points with opinion inertia

    Science.gov (United States)

    Doyle, C.; Sreenivasan, S.; Szymanski, B. K.; Korniss, G.

    2016-02-01

    When opinions, behaviors or ideas diffuse within a population, some are invariably more sticky than others. The stickier the opinion, behavior or idea, the greater is an individual's inertia to replace it with an alternative. Here we study the effect of stickiness of opinions in a two-opinion model, where individuals change their opinion only after a certain number of consecutive encounters with the alternative opinion. Assuming that one opinion has a fixed stickiness, we investigate how the critical size of the competing opinion required to tip over the entire population varies as a function of the competing opinion's stickiness. We analyze this scenario for the case of a complete-graph topology through simulations, and through a semi-analytical approach which yields an upper bound for the critical minority size. We present analogous simulation results for the case of the Erdős-Rényi random network. Finally, we investigate the coarsening properties of sticky opinion spreading on two-dimensional lattices, and show that the presence of stickiness gives rise to an effective surface tension that causes the coarsening behavior to become curvature-driven.

  4. Uncertainty of tipping elements on risk analysis in hydrology under climate change

    Science.gov (United States)

    Kiguchi, M.; Iseri, Y.; Tawatari, R.; Kanae, S.; Oki, T.

    2015-12-01

    Risk analysis in this study characterizes the events that could be caused by climate change and estimates their effects on society. In order to characterize climate change risks, events that might be caused by climate change will be investigated focusing on critical geophysical phenomena such as changes in thermohaline circulation (THC) in oceans and the large-scale melting of the Greenland and other ice sheets. The results of numerical experiments with climate models and paleoclimate studies will be referenced in listing up these phenomena. The trigger mechanisms, tendency to occur and relationship of these phenomena to global climate will be clarified. To clarify that relationship between the RCP scenarios and tipping elements, we identified which year tipping elements in case of "Arctic summer sea ice" and "Greenland ice sheet" are appeared using the increase of global average temperature in 5 GCMs under RCP (2.6, 4.5, 6.0, and 8.5) from Zickfeld et al. (2013) and IPCC (2013), and tipping point of each tipping elements from IPCC (2013). In case of "Greenland ice sheet" (Tipping point takes a value within the range of 1.0oC and 4.0oC), we found that "Greenland ice sheet" may melt down when the tipping point is 1.0oC as lowest value. On the other hand, when tipping point sets as 4.0oC, it may not melt down except for RCP 8.5. As above, we show the uncertainty of tipping point itself. In future, it is necessary how to reflect such uncertainty in risk analysis in hydrology.

  5. Analytic treatment of tipping points for social consensus in large random networks.

    Science.gov (United States)

    Zhang, W; Lim, C; Szymanski, B K

    2012-12-01

    We introduce a homogeneous pair approximation to the naming game (NG) model by deriving a six-dimensional Open Dynamics Engine (ODE) for the two-word naming game. Our ODE reveals the change in dynamical behavior of the naming game as a function of the average degree {k} of an uncorrelated network. This result is in good agreement with the numerical results. We also analyze the extended NG model that allows for presence of committed nodes and show that there is a shift of the tipping point for social consensus in sparse networks.

  6. Scanning tip measurement for identification of point defects.

    Science.gov (United States)

    Dózsa, László; Molnár, György; Raineri, Vito; Giannazzo, Filippo; Ferencz, János; Lányi, Stefan

    2011-01-01

    Self-assembled iron-silicide nanostructures were prepared by reactive deposition epitaxy of Fe onto silicon. Capacitance-voltage, current-voltage, and deep level transient spectroscopy (DLTS) were used to measure the electrical properties of Au/silicon Schottky junctions. Spreading resistance and scanning probe capacitance microscopy (SCM) were applied to measure local electrical properties. Using a preamplifier the sensitivity of DLTS was increased satisfactorily to measure transients of the scanning tip semiconductor junction. In the Fe-deposited area, Fe-related defects dominate the surface layer in about 0.5 μm depth. These defects deteriorated the Schottky junction characteristic. Outside the Fe-deposited area, Fe-related defect concentration was identified in a thin layer near the surface. The defect transients in this area were measured both in macroscopic Schottky junctions and by scanning tip DLTS and were detected by bias modulation frequency dependence in SCM. PMID:21711635

  7. Scanning tip measurement for identification of point defects

    Directory of Open Access Journals (Sweden)

    Raineri Vito

    2011-01-01

    Full Text Available Abstract Self-assembled iron-silicide nanostructures were prepared by reactive deposition epitaxy of Fe onto silicon. Capacitance-voltage, current-voltage, and deep level transient spectroscopy (DLTS were used to measure the electrical properties of Au/silicon Schottky junctions. Spreading resistance and scanning probe capacitance microscopy (SCM were applied to measure local electrical properties. Using a preamplifier the sensitivity of DLTS was increased satisfactorily to measure transients of the scanning tip semiconductor junction. In the Fe-deposited area, Fe-related defects dominate the surface layer in about 0.5 μm depth. These defects deteriorated the Schottky junction characteristic. Outside the Fe-deposited area, Fe-related defect concentration was identified in a thin layer near the surface. The defect transients in this area were measured both in macroscopic Schottky junctions and by scanning tip DLTS and were detected by bias modulation frequency dependence in SCM.

  8. Automated fabrication technique of gold tips for use in point-contact spectroscopy

    CERN Document Server

    Narasiwodeyar, S; Liu, M; Park, W K; Greene, L H

    2014-01-01

    For a successful point-contact spectroscopy (PCS) measurement, metallic tips of proper shape and smoothness are essential to ensure the ballistic nature of a point-contact junction. Until recently, the fabrication of Au tips suitable for use in point-contact spectroscopy has remained more of an art involving a trial and error method rather than an automated scientific process. To address these issues, we have developed a technique with which one can prepare high quality Au tips reproducibly and systematically. It involves an electronic control of the driving voltages used for an electrochemical etching of a gold wire in an HCl-glycerol mixture or an HCl solution. We find that a stopping current, below which the circuit is set to shut off, is a single very important parameter to produce an Au tip of desired shape. We present detailed descriptions for a two-step etching process for Au tips and also test results from PCS measurements using them.

  9. Two-step fabrication technique of gold tips for use in point-contact spectroscopy

    International Nuclear Information System (INIS)

    For a successful point-contact spectroscopy (PCS) measurement, metallic tips of proper shape and smoothness are essential to ensure the ballistic nature of a point-contact junction. Until recently, the fabrication of Au tips suitable for use in point-contact spectroscopy has remained more of an art involving a trial and error method rather than an automated scientific process. To address these issues, we have developed a technique with which one can prepare high quality Au tips reproducibly and systematically. It involves an electronic control of the driving voltages used for an electrochemical etching of a gold wire in a HCl-glycerol mixture or a HCl solution. We find that a stopping current, below which the circuit is set to shut off, is a single very important parameter to produce an Au tip of desired shape. We present detailed descriptions for a two-step etching process for Au tips and also test results from PCS measurements using them

  10. Searching for tipping points in Pleistocene climate: Are they real? Are they portents for the future?

    Science.gov (United States)

    Mix, A. C.

    2015-12-01

    Paleoscientists seek fundamental knowledge of Earth systems, and have unique views of system dynamics on the timescales longer than recent observations. This is important, because some processes that may control the trajectory of change in the not-so-distant future are not well illustrated or constrained in the short history of instrumental observations; paleo data offer our only observational window on these longer scales. But paleo vision is also a bit blurry, and sometimes biased. It matters how we approach the records to focus on the right things, and it matters how we communicate our insights so that we can teach models to approximate real Earth system behaviors. In the six decades since Cesare Emiliani set us on the path of quantitative observational paleoscience, we've observed more and more. Each year brings more "proxies," more sites, more resolution, and the more we look the more we find interpretable signals. This data complexity makes the paleo literature daunting to outsiders; it is hard to get past the stories. Most of our narratives are grounded in linear systems, focusing on forcing and response, and we data generators struggle to infer even modest nonlinearity. But the concept of massive nonlinearity, tipping points, has recently entered the public consciousness, and the search is on anew for such events in paleo data. The reality of tipping points as well as the processes that may drive such events are not yet fully clear, but the search is essential because if humanity does indeed push the Earth system across an irreversible tipping point into a new state, we need to know how this might play out and over what time frames. Can we really learn about such occurrences, and the processes that control them, in paleo records? Do we need to think about the past differently? Will this change how we think about the future? Will it inform what we do about the future? Emiliani thought it should. This lecture will explore how.

  11. Conductance of a Quantum Point Contact in the presence of a Scanning Probe Microscope Tip

    OpenAIRE

    Wang, ZD; He, GP; Zhu, SL

    2002-01-01

    Using the recursive Green's-function technique, we study the coherent electron conductance of a quantum point contact in the presence of a scanning probe microscope tip. Images of the coherent fringe inside a quantum point contact for different widths are obtained. It is found that the conductance of a specific channel is reduced while other channels are not affected, as long as the tip is located at the positions corresponding to that channel. Moreover, the coherent fringe is smoothed out by...

  12. Multiple tipping points and optimal repairing in interacting networks

    Science.gov (United States)

    Majdandzic, Antonio; Braunstein, Lidia A.; Curme, Chester; Vodenska, Irena; Levy-Carciente, Sary; Eugene Stanley, H.; Havlin, Shlomo

    2016-03-01

    Systems composed of many interacting dynamical networks--such as the human body with its biological networks or the global economic network consisting of regional clusters--often exhibit complicated collective dynamics. Three fundamental processes that are typically present are failure, damage spread and recovery. Here we develop a model for such systems and find a very rich phase diagram that becomes increasingly more complex as the number of interacting networks increases. In the simplest example of two interacting networks we find two critical points, four triple points, ten allowed transitions and two `forbidden' transitions, as well as complex hysteresis loops. Remarkably, we find that triple points play the dominant role in constructing the optimal repairing strategy in damaged interacting systems. To test our model, we analyse an example of real interacting financial networks and find evidence of rapid dynamical transitions between well-defined states, in agreement with the predictions of our model.

  13. Multiple Tipping Points and Optimal Repairing in Interacting Networks

    CERN Document Server

    Majdandzic, Antonio; Curme, Chester; Vodenska, Irena; Levy-Carciente, Sary; Stanley, H Eugene; Havlin, Shlomo

    2015-01-01

    Systems that comprise many interacting dynamical networks, such as the human body with its biological networks or the global economic network consisting of regional clusters, often exhibit complicated collective dynamics. To understand the collective behavior of these systems, we investigate a model of interacting networks exhibiting the fundamental processes of failure, damage spread, and recovery. We find a very rich phase diagram that becomes exponentially more complex as the number of networks is increased. In the simplest example of $n=2$ interacting networks we find two critical points, 4 triple points, 10 allowed transitions, and two "forbidden" transitions, as well as a manifold of metastable regions represented by complex hysteresis. Knowing and understanding the phase diagram have an immediate practical implication; it enables us to find the optimal strategy for repairing partially or fully damaged interconnected networks. To support our model, we analyze an example of real interacting financial net...

  14. Risk of multiple interacting tipping points should encourage rapid CO2 emission reduction

    Science.gov (United States)

    Cai, Yongyang; Lenton, Timothy M.; Lontzek, Thomas S.

    2016-05-01

    Evidence suggests that several elements of the climate system could be tipped into a different state by global warming, causing irreversible economic damages. To address their policy implications, we incorporated five interacting climate tipping points into a stochastic-dynamic integrated assessment model, calibrating their likelihoods and interactions on results from an existing expert elicitation. Here we show that combining realistic assumptions about policymakers’ preferences under uncertainty, with the prospect of multiple future interacting climate tipping points, increases the present social cost of carbon in the model nearly eightfold from US$15 per tCO2 to US$116 per tCO2. Furthermore, passing some tipping points increases the likelihood of other tipping points occurring to such an extent that it abruptly increases the social cost of carbon. The corresponding optimal policy involves an immediate, massive effort to control CO2 emissions, which are stopped by mid-century, leading to climate stabilization at <1.5 °C above pre-industrial levels.

  15. Ocean acidification impacts on sperm mitochondrial membrane potential bring sperm swimming behaviour near its tipping point.

    Science.gov (United States)

    Schlegel, Peter; Binet, Monique T; Havenhand, Jonathan N; Doyle, Christopher J; Williamson, Jane E

    2015-04-01

    Broadcast spawning marine invertebrates are susceptible to environmental stressors such as climate change, as their reproduction depends on the successful meeting and fertilization of gametes in the water column. Under near-future scenarios of ocean acidification, the swimming behaviour of marine invertebrate sperm is altered. We tested whether this was due to changes in sperm mitochondrial activity by investigating the effects of ocean acidification on sperm metabolism and swimming behaviour in the sea urchin Centrostephanus rodgersii. We used a fluorescent molecular probe (JC-1) and flow cytometry to visualize mitochondrial activity (measured as change in mitochondrial membrane potential, MMP). Sperm MMP was significantly reduced in ΔpH -0.3 (35% reduction) and ΔpH -0.5 (48% reduction) treatments, whereas sperm swimming behaviour was less sensitive with only slight changes (up to 11% decrease) observed overall. There was significant inter-individual variability in responses of sperm swimming behaviour and MMP to acidified seawater. We suggest it is likely that sperm exposed to these changes in pH are close to their tipping point in terms of physiological tolerance to acidity. Importantly, substantial inter-individual variation in responses of sperm swimming to ocean acidification may increase the scope for selection of resilient phenotypes, which, if heritable, could provide a basis for adaptation to future ocean acidification.

  16. Leading bureaucracies to the tipping point: an alternative model of multiple stable equilibrium levels of corruption

    NARCIS (Netherlands)

    Caulkins, J.P.; Feichtinger, G.; Grass, D.; Hartl, R.F.; Kort, P.M.; Novak, A.J.; Seidl, A.

    2013-01-01

    We present a novel model of corruption dynamics in the form of a nonlinear optimal dynamic control problem. It has a tipping point, but one whose origins and character are distinct from that in the classic Schelling (1978) model. The decision maker choosing a level of corruption is the chief or some

  17. Parametric statistical change point analysis

    CERN Document Server

    Chen, Jie

    2000-01-01

    This work is an in-depth study of the change point problem from a general point of view and a further examination of change point analysis of the most commonly used statistical models Change point problems are encountered in such disciplines as economics, finance, medicine, psychology, signal processing, and geology, to mention only several The exposition is clear and systematic, with a great deal of introductory material included Different models are presented in each chapter, including gamma and exponential models, rarely examined thus far in the literature Other models covered in detail are the multivariate normal, univariate normal, regression, and discrete models Extensive examples throughout the text emphasize key concepts and different methodologies are used, namely the likelihood ratio criterion, and the Bayesian and information criterion approaches A comprehensive bibliography and two indices complete the study

  18. Tipping Point

    Medline Plus

    Full Text Available ... injuries than from exposed electrical outlets. Unfortunately, many parents are unaware of the deadly danger of this hidden hazard. Parents should include securing TVs, furniture, and appliances in ...

  19. Tipping Point

    Medline Plus

    Full Text Available ... Childproofing CPSC danger death electrical fall furniture head injury product safety television tipover tv Watch the video ... impact can kill a child or cause severe injuries. About 16,000 (mostly young children) were treated ...

  20. Tipping Point

    Medline Plus

    Full Text Available ... Google Plus Reddit Connect with Me: Visit other Web Sites Maintained by CPSC: cpsc.gov| poolsafely.gov| recalls.gov| saferproducts.gov Privacy, Security, and Legal Notice | Accessibility Policy | Open Government @ CPSC | ...

  1. Robust seasonal cycle of Arctic sea ice area through tipping point in amplitude

    CERN Document Server

    Ditlevsen, Peter D

    2012-01-01

    The variation in the Arctic sea ice is dominated by the seasonal cycle with little inter-annual correlation. Though the mean sea ice area has decreased steadily in the period of satellite observations, a dramatic transition in the dynamics was initiated with the record low September ice area in 2007. The change is much more pronounced in the amplitude of the seasonal cycle than in the annual mean ice area. The shape of the seasonal cycle is surprisingly constant for the whole observational record despite the general decline. A simple explanation, independent of the increased greenhouse warming, for the shape of the seasonal cycle is offered. Thus the dramatic climate change in arctic ice area is seen in the amplitude of the cycle and to a lesser extend the annual mean and the summer ice extend. The reason why the climate change is most pronounced in the amplitude is related to the rapid reduction in perennial ice and thus a thinning of the ice. The analysis shows that a tipping point for the arctic ice area w...

  2. A framework for measuring TRE at the tip of an optically tracked pointing stylus

    Science.gov (United States)

    Simpson, Amber L.; Dillon, Neal P.; Miga, Michael I.; Ma, Burton

    2013-03-01

    We describe a framework for measuring TRE at the tip of an optically tracked pointing stylus. Our approach relied on a robotic manipulator equipped with a spherical wrist to collect large amounts of tracking data from well defined paths. Fitting the tracking data to planes, circles, and spheres allowed us to derive estimates of FLE and precisely localize target locations. A preliminary analysis of our data suggested that there was bias in the registered pointer tip location that depended on the tilt angle of the coordinate reference frame with respect to the tracking system.

  3. Rapid Elevation in CMPF May Act As a Tipping Point in Diabetes Development.

    Science.gov (United States)

    Liu, Ying; Prentice, Kacey J; Eversley, Judith A; Hu, Cheng; Batchuluun, Battsetseg; Leavey, Katherine; Hansen, Jakob B; Wei, David W; Cox, Brian; Dai, Feihan F; Jia, Weiping; Wheeler, Michael B

    2016-03-29

    Prediabetes, a state of mild glucose intolerance, can persist for years before a sudden decline in beta cell function and rapid deterioration to overt diabetes. The mechanism underlying this tipping point of beta cell dysfunction remains unknown. Here, the furan fatty acid metabolite CMPF was evaluated in a prospective cohort. Those who developed overt diabetes had a significant increase in CMPF over time, whereas prediabetics maintained chronically elevated levels, even up to 5 years before diagnosis. To evaluate the effect of increasing CMPF on diabetes progression, we used obese, insulin-resistant models of prediabetes. CMPF accelerated diabetes development by inducing metabolic remodeling, resulting in preferential utilization of fatty acids over glucose. This was associated with diminished glucose-stimulated insulin secretion, increased ROS formation, and accumulation of proinsulin, all characteristics of human diabetes. Thus, an increase in CMPF may represent the tipping point in diabetes development by accelerating beta cell dysfunction. PMID:26997281

  4. Rapid Elevation in CMPF May Act As a Tipping Point in Diabetes Development

    Directory of Open Access Journals (Sweden)

    Ying Liu

    2016-03-01

    Full Text Available Prediabetes, a state of mild glucose intolerance, can persist for years before a sudden decline in beta cell function and rapid deterioration to overt diabetes. The mechanism underlying this tipping point of beta cell dysfunction remains unknown. Here, the furan fatty acid metabolite CMPF was evaluated in a prospective cohort. Those who developed overt diabetes had a significant increase in CMPF over time, whereas prediabetics maintained chronically elevated levels, even up to 5 years before diagnosis. To evaluate the effect of increasing CMPF on diabetes progression, we used obese, insulin-resistant models of prediabetes. CMPF accelerated diabetes development by inducing metabolic remodeling, resulting in preferential utilization of fatty acids over glucose. This was associated with diminished glucose-stimulated insulin secretion, increased ROS formation, and accumulation of proinsulin, all characteristics of human diabetes. Thus, an increase in CMPF may represent the tipping point in diabetes development by accelerating beta cell dysfunction.

  5. Daredevil barnstorming to the tipping point: new aspirations for the human sciences.

    Science.gov (United States)

    Fisher, William P

    2005-01-01

    Aviation history provides an apt metaphor for the state of Rasch measurement practice, and its potential future. Flying was initially widely believed to be nothing but a spectacular and dangerous fad. Few saw in it any potential for the huge industry that it is today. The current state of Rasch measurement practice is quite akin to daredevil barnstorming in that the field is focused on isolated demonstrations of disconnected technical effects. Only when the analogues of air traffic control, airports, support staff, training programs, textbooks, and partner industries (hotels, restaurants) are in place will Rasch measurement come into its own as the technical medium of a widespread industry. The point at which current practice tips into a new paradigm depends on the realization of operationally validated theory in a supportive social context. The paper closes with speculations on what crossing Rasch measurement's tipping point might entail.

  6. Weather instabilities as a warning sign for a nearby climatic tipping point?

    CERN Document Server

    Louchet, Francois

    2016-01-01

    Using in a simple way the theory of non linear dynamical systems, we show that increasing climatic instabilities may be a qualitative warning sign for the occurrence of a nearby bifurcation, yielding a discontinuous and sudden climate tipping towards an unknown and unpredictable state. The possibility of an accurate prediction of the occurrence time of such a transition is also discussed in terms of the approach of a critical point.

  7. Leading bureaucracies to the tipping point: An alternative model of multiple stable equilibrium levels of corruption.

    Science.gov (United States)

    Caulkins, Jonathan P; Feichtinger, Gustav; Grass, Dieter; Hartl, Richard F; Kort, Peter M; Novak, Andreas J; Seidl, Andrea

    2013-03-16

    We present a novel model of corruption dynamics in the form of a nonlinear optimal dynamic control problem. It has a tipping point, but one whose origins and character are distinct from that in the classic Schelling (1978) model. The decision maker choosing a level of corruption is the chief or some other kind of authority figure who presides over a bureaucracy whose state of corruption is influenced by the authority figure's actions, and whose state in turn influences the pay-off for the authority figure. The policy interpretation is somewhat more optimistic than in other tipping models, and there are some surprising implications, notably that reforming the bureaucracy may be of limited value if the bureaucracy takes its cues from a corrupt leader.

  8. Using GENIE to study a tipping point in the climate system

    OpenAIRE

    Lenton, Timothy M.; Myerscough, Richard J.; Marsh, Robert; Livina, Valerie N.; Price, Andrew R.; Cox, Simon J.

    2009-01-01

    We have used the Grid ENabled Integrated Earth system modelling framework to study the archetypal example of a tipping point in the climate system; a threshold for the collapse of the Atlantic thermohaline circulation (THC). eScience has been invaluable in this work and we explain how we have made it work for us. Two stable states of the THC have been found to coexist, under the same boundary conditions, in a hierarchy of models. The climate forcing required to collapse the THC and the revers...

  9. Improving Multi-Objective Management of Water Quality Tipping Points: Revisiting the Classical Shallow Lake Problem

    Science.gov (United States)

    Quinn, J. D.; Reed, P. M.; Keller, K.

    2015-12-01

    Recent multi-objective extensions of the classical shallow lake problem are useful for exploring the conceptual and computational challenges that emerge when managing irreversible water quality tipping points. Building on this work, we explore a four objective version of the lake problem where a hypothetical town derives economic benefits from polluting a nearby lake, but at the risk of irreversibly tipping the lake into a permanently polluted state. The trophic state of the lake exhibits non-linear threshold dynamics; below some critical phosphorus (P) threshold it is healthy and oligotrophic, but above this threshold it is irreversibly eutrophic. The town must decide how much P to discharge each year, a decision complicated by uncertainty in the natural P inflow to the lake. The shallow lake problem provides a conceptually rich set of dynamics, low computational demands, and a high level of mathematical difficulty. These properties maximize its value for benchmarking the relative merits and limitations of emerging decision support frameworks, such as Direct Policy Search (DPS). Here, we explore the use of DPS as a formal means of developing robust environmental pollution control rules that effectively account for deeply uncertain system states and conflicting objectives. The DPS reformulation of the shallow lake problem shows promise in formalizing pollution control triggers and signposts, while dramatically reducing the computational complexity of the multi-objective pollution control problem. More broadly, the insights from the DPS variant of the shallow lake problem formulated in this study bridge emerging work related to socio-ecological systems management, tipping points, robust decision making, and robust control.

  10. Tipping points? Ethnic composition change in Dutch big city neighbourhoods

    NARCIS (Netherlands)

    Ong, C.

    2014-01-01

    Micro-level studies using individual and household data have shown that residential location choices are influenced by neighbourhood ethnic composition. Using three conurbation samples in the Netherlands - Amsterdam metropolitan area, Rotterdam-The Hague metropolitan area, and the country's largest

  11. Adverse trends in male reproductive health: we may have reached a crucial 'tipping point'

    DEFF Research Database (Denmark)

    Andersson, A.-M.; Jørgensen, N.; Main, K. M.;

    2008-01-01

    of young men in Northern Europe show that semen quality is much poorer. In Denmark approximately 40 percent of the men have now sperm counts below 40 mill/mL. A simulation assuming that average sperm count had declined from 100 mill/mL in 'old times' to a current level close to 40 mill/mL indicated...... that the first decline in average sperm number of 20-40 mill/mL might not have had much effect on pregnancy rates, as the majority of men would still have had counts far above the threshold value. However, due to the assumed decline in semen quality, the sperm counts of the majority of 20 year old European men...... are now so low that we may be close to the crucial tipping point of 40 mill/mL spermatozoa. Consequently, we must face the possibility of more infertile couples and lower fertility rates in the future....

  12. Distance of cleavage trigger point (weakest-link) to the crack tip - fractographic analysis

    International Nuclear Information System (INIS)

    Among the existing approaches approaches to predict Jc, in the transition region of the ferritic steels, there are statistical and deterministic methods. Among the formers we have the methodology based on the two-parameter J-Q theory and the weakest-link concept with its characteristic distance, rwl. For this work, an experimental program was developed using 65 fracture mechanics specimens made from an A508 steel, in three geometries with thickness B c, all specimen fracture surfaces were observed by scanning electron microscopy to identify the cleavage trigger points (weak-links) and to measure their characteristic distances rwl to the crap tip. The Jc and rwl values were presented and compared with the theoretical ones. (author)

  13. WWBT? What Would Ben Think about Killer Apps, Cutting Edges, and Tipping Points in the History of Weather and Climate?

    Science.gov (United States)

    Fleming, J. R.

    2006-12-01

    This paper examines the history of weather and climate since 1706 along three intertwined analytical axes: technology (killer apps), science (cutting edges), and social issues (tipping points). For example, Franklin's best-known killer app, the lightning rod, gains added significance when seen in light of his cutting edge contributions to the science of electricity, his lifelong promotion of useful knowledge, and the societal tipping point his work triggered in our relationship to the sky. Subsequently, other major tipping points and conceptual shifts followed the introduction of telegraphy, radio, television, digital computers, and rocketry into meteorology. Following an analysis of the career and contributions of Benjamin Franklin (1706-1790), the paper examines later historical moments and watersheds, not merely in retrospect, but from the perspective of leading participants at the time. It focuses on technologies of significant promise, especially those involving electro- magnetism, up to and including the dawn of the twenty-first century, and asks playfully, "What would Ben think?"

  14. Near-field microscopy with a single-photon point-like emitter: Resolution versus the aperture tip?

    CERN Document Server

    Drezet, A; Huant, S

    2014-01-01

    We discuss theoretically the concept of spatial resolution in near-field scanning optical microscopy (NSOM) in light of a recent work [Opt. Express 17 (2009) 19969] which reported on the achievement of active tips made of a single ultrasmall fluorescent nanodiamond grafted onto the apex of a substrate tip and on their validation in NSOM imaging. Since fluorescent nanodiamonds tend to decrease steadily in size, we assimilate a nanodiamond-based tip to a point-like single photon source and compare its ultimate resolution with that offered by standard metal-coated aperture NSOM tips. We demonstrate both classically and quantum mechanically that NSOM based on a point-like tip has a resolving power that is only limited by the scan height over the imaged system whereas the aperture-tip resolution depends critically on both the scan height and aperture diameter. This is a consequence of the complex distribution of the electromagnetic field around the aperture that tends to artificially duplicate the imaged objects. ...

  15. Ecosystem thresholds: Interrelated tipping points in broad-scale tree mortality, fire regimes, and ecohydrological dynamics (Invited)

    Science.gov (United States)

    Allen, C. D.

    2010-12-01

    Climate variability and land use are key drivers of interrelated changes in ecosystem patterns and disturbance processes, including broad-scale tree mortality, fire regimes, and ecohydrological runoff and erosion dynamics. Pervasive ecosystem changes have occurred over the past century in montane landscapes of the southwestern USA, with forest die-off and severe fire activity affecting millions of hectares since the late 1990s, a period including severe drought and unusual warmth. Current and historic patterns of vegetation change, forest die-off (and associated insect outbreaks), fire activity, and runoff and erosion dynamics are described for the Southwest (particularly the Jemez Mountains of New Mexico) to illustrate nonlinear threshold responses to climate and land use stressors. In addition, a recent global overview of drought and heat-induced tree mortality (Allen et al., 2010, Forest Ecology and Management 259:660-684) highlights the central role of thresholds in processes at fine spatial scales to drive tipping points in tree mortality that can propagate at landscape and even sub-continental scales. These climate-driven increases in both chronic background tree mortality rates and episodes of rapid, broad-scale forest mortality are linked to thresholds in tree physiological stress responses, sometimes amplified by epidemic dynamics of associated biotic agents (e.g., bark beetles in western North America). Methods for these results include dendrochronological reconstructions of tree demographies and fire regimes, dendrometer measurements of pine tree-growth since 1991 and associated tree-ring studies of stable carbon isotopes, monitoring of herbaceous vegetation along 3 km of permanent transects since 1991, photographic and remote-sensing interpretation of forest die-off and fire activity, intensive storm-event-resolution measurements of runoff and erosion at multiple spatial scales from a 1.09 ha watershed since 1993, and ongoing research on the patterns

  16. Adverse trends in male reproductive health: we may have reached a crucial 'tipping point'

    DEFF Research Database (Denmark)

    Andersson, A.M.; Jorgensen, N.; Main, K.M.;

    2008-01-01

    of young men in Northern Europe show that semen quality is much poorer. In Denmark approximately 40 percent of the men have now sperm counts below 40 mill/mL. A simulation assuming that average sperm count had declined from 100 mill/mL in 'old times' to a current level close to 40 mill/mL indicated...... that the first decline in average sperm number of 20-40 mill/mL might not have had much effect on pregnancy rates, as the majority of men would still have had counts far above the threshold value. However, due to the assumed decline in semen quality, the sperm counts of the majority of 20 year old European men...... are now so low that we may be close to the crucial tipping point of 40 mill/mL spermatozoa. Consequently, we must face the possibility of more infertile couples and lower fertility rates in the future Udgivelsesdato: 2008/4...

  17. Psychosexual therapy for delayed ejaculation based on the Sexual Tipping Point model.

    Science.gov (United States)

    Perelman, Michael A

    2016-08-01

    The Sexual Tipping Point(®) (STP) model is an integrated approach to the etiology, diagnosis and treatment of men with delayed ejaculation (DE), including all subtypes manifesting ejaculatory delay or absence [registered trademark owned by the MAP Educational Fund, a 501(c)(3) public charity]. A single pathogenetic pathway does not exist for sexual disorders generally and that is also true for DE specifically. Men with DE have various bio-psychosocial-behavioral & cultural predisposing, precipitating, maintaining, and contextual factors which trigger, reinforce, or worsen the probability of DE occurring. Regardless of the degree of organic etiology present, DE is exacerbated by insufficient stimulation: an inadequate combination of "friction and fantasy". High frequency negative thoughts may neutralize erotic cognitions (fantasy) and subsequently delay, ameliorate, or inhibit ejaculation, while partner stimulation (friction) may prove unsatisfying. Assessment requires a thorough sexual history including inquiry into masturbatory methods. Many men with DE engage in an idiosyncratic masturbatory style, defined as a masturbation technique not easily duplicated by the partner's hand, mouth, or vagina. The clinician's most valuable diagnostic tool is a focused sex history (sex status). Differentiate DE from other sexual problems and review the conditions under which the man can ejaculate. Perceived partner attractiveness, the use of fantasy during sex, anxiety-surrounding coitus and masturbatory patterns require meticulous exploration. Identify important DE causes by juxtaposing an awareness of his cognitions and the sexual stimulation experienced during masturbation, versus a partnered experience. Assist the man in identifying behaviors that enhance immersion in excitation and minimize inhibiting thoughts, in order to reach ejaculation in his preferred manner. Discontinuing, reducing or altering masturbation is often required, which evokes patient resistance. Coaching

  18. Detecting change-points in extremes

    KAUST Repository

    Dupuis, D. J.

    2015-01-01

    Even though most work on change-point estimation focuses on changes in the mean, changes in the variance or in the tail distribution can lead to more extreme events. In this paper, we develop a new method of detecting and estimating the change-points in the tail of multiple time series data. In addition, we adapt existing tail change-point detection methods to our specific problem and conduct a thorough comparison of different methods in terms of performance on the estimation of change-points and computational time. We also examine three locations on the U.S. northeast coast and demonstrate that the methods are useful for identifying changes in seasonally extreme warm temperatures.

  19. A recent tipping point in the Arctic sea-ice cover: abrupt and persistent increase in the seasonal cycle since 2007

    Directory of Open Access Journals (Sweden)

    V. N. Livina

    2013-02-01

    Full Text Available There is ongoing debate over whether Arctic sea ice has already passed a "tipping point", or whether it will do so in the future. Several recent studies argue that the loss of summer sea ice does not involve an irreversible bifurcation, because it is highly reversible in models. However, a broader definition of a "tipping point" also includes other abrupt, non-linear changes that are neither bifurcations nor necessarily irreversible. Examination of satellite data for Arctic sea-ice area reveals an abrupt increase in the amplitude of seasonal variability in 2007 that has persisted since then. We identified this abrupt transition using recently developed methods that can detect multi-modality in time-series data and sometimes forewarn of bifurcations. When removing the mean seasonal cycle (up to 2008 from the satellite data, the residual sea-ice fluctuations switch from uni-modal to multi-modal behaviour around 2007. We originally interpreted this as a bifurcation in which a new lower ice cover attractor appears in deseasonalised fluctuations and is sampled in every summer–autumn from 2007 onwards. However, this interpretation is clearly sensitive to how the seasonal cycle is removed from the raw data, and to the presence of continental land masses restricting winter–spring ice fluctuations. Furthermore, there was no robust early warning signal of critical slowing down prior to the hypothesized bifurcation. Early warning indicators do however show destabilization of the summer–autumn sea-ice cover since 2007. Thus, the bifurcation hypothesis lacks consistent support, but there was an abrupt and persistent increase in the amplitude of the seasonal cycle of Arctic sea-ice cover in 2007, which we describe as a (non-bifurcation "tipping point". Our statistical methods detect this "tipping point" and its time of onset. We discuss potential geophysical mechanisms behind it, which should be the subject of further work with process-based models.

  20. Psychosexual therapy for delayed ejaculation based on the Sexual Tipping Point model

    Science.gov (United States)

    2016-01-01

    The Sexual Tipping Point® (STP) model is an integrated approach to the etiology, diagnosis and treatment of men with delayed ejaculation (DE), including all subtypes manifesting ejaculatory delay or absence [registered trademark owned by the MAP Educational Fund, a 501(c)(3) public charity]. A single pathogenetic pathway does not exist for sexual disorders generally and that is also true for DE specifically. Men with DE have various bio-psychosocial-behavioral & cultural predisposing, precipitating, maintaining, and contextual factors which trigger, reinforce, or worsen the probability of DE occurring. Regardless of the degree of organic etiology present, DE is exacerbated by insufficient stimulation: an inadequate combination of “friction and fantasy”. High frequency negative thoughts may neutralize erotic cognitions (fantasy) and subsequently delay, ameliorate, or inhibit ejaculation, while partner stimulation (friction) may prove unsatisfying. Assessment requires a thorough sexual history including inquiry into masturbatory methods. Many men with DE engage in an idiosyncratic masturbatory style, defined as a masturbation technique not easily duplicated by the partner’s hand, mouth, or vagina. The clinician’s most valuable diagnostic tool is a focused sex history (sex status). Differentiate DE from other sexual problems and review the conditions under which the man can ejaculate. Perceived partner attractiveness, the use of fantasy during sex, anxiety-surrounding coitus and masturbatory patterns require meticulous exploration. Identify important DE causes by juxtaposing an awareness of his cognitions and the sexual stimulation experienced during masturbation, versus a partnered experience. Assist the man in identifying behaviors that enhance immersion in excitation and minimize inhibiting thoughts, in order to reach ejaculation in his preferred manner. Discontinuing, reducing or altering masturbation is often required, which evokes patient resistance

  1. Psychosexual therapy for delayed ejaculation based on the Sexual Tipping Point model

    Science.gov (United States)

    2016-01-01

    The Sexual Tipping Point® (STP) model is an integrated approach to the etiology, diagnosis and treatment of men with delayed ejaculation (DE), including all subtypes manifesting ejaculatory delay or absence [registered trademark owned by the MAP Educational Fund, a 501(c)(3) public charity]. A single pathogenetic pathway does not exist for sexual disorders generally and that is also true for DE specifically. Men with DE have various bio-psychosocial-behavioral & cultural predisposing, precipitating, maintaining, and contextual factors which trigger, reinforce, or worsen the probability of DE occurring. Regardless of the degree of organic etiology present, DE is exacerbated by insufficient stimulation: an inadequate combination of “friction and fantasy”. High frequency negative thoughts may neutralize erotic cognitions (fantasy) and subsequently delay, ameliorate, or inhibit ejaculation, while partner stimulation (friction) may prove unsatisfying. Assessment requires a thorough sexual history including inquiry into masturbatory methods. Many men with DE engage in an idiosyncratic masturbatory style, defined as a masturbation technique not easily duplicated by the partner’s hand, mouth, or vagina. The clinician’s most valuable diagnostic tool is a focused sex history (sex status). Differentiate DE from other sexual problems and review the conditions under which the man can ejaculate. Perceived partner attractiveness, the use of fantasy during sex, anxiety-surrounding coitus and masturbatory patterns require meticulous exploration. Identify important DE causes by juxtaposing an awareness of his cognitions and the sexual stimulation experienced during masturbation, versus a partnered experience. Assist the man in identifying behaviors that enhance immersion in excitation and minimize inhibiting thoughts, in order to reach ejaculation in his preferred manner. Discontinuing, reducing or altering masturbation is often required, which evokes patient resistance

  2. Turning points in climate change adaptation

    Directory of Open Access Journals (Sweden)

    Saskia Elisabeth. Werners

    2015-12-01

    Full Text Available Concerned decision makers increasingly pose questions as to whether current management practices are able to cope with climate change and increased climate variability. This signifies a shift in the framing of climate change from asking what its potential impacts are to asking whether it induces policy failure and unacceptable change. In this paper, we explore the background, feasibility, and consequences of this new framing. We focus on the specific situation in which a social-political threshold of concern is likely to be exceeded as a result of climate change, requiring consideration of alternative strategies. Action is imperative when such a situation is conceivable, and at this point climate change becomes particularly relevant to decision makers. We call this situation an "adaptation turning point." The assessment of adaptation turning points converts uncertainty surrounding the extent of a climate impact into a time range over which it is likely that specific thresholds will be exceeded. This can then be used to take adaptive action. Despite the difficulty in identifying adaptation turning points and the relative newness of the approach, experience so far suggests that the assessment generates a meaningful dialogue between stakeholders and scientists. Discussion revolves around the amount of change that is acceptable; how likely it is that unacceptable, or more favorable, conditions will be reached; and the adaptation pathways that need to be considered under these circumstances. Defining and renegotiating policy objectives under climate change are important topics in the governance of adaptation.

  3. Tipping Points and Balancing Acts: Grand Challenges and Synergistic Opportunities of Integrating Research and Education, Science and Solutions

    Science.gov (United States)

    McCaffrey, M. S.; Stroeve, J. C.

    2011-12-01

    thousands of US high schools that integrate climate science and solutions in a way that inspires and informs youth, and similar programs exist internationally. Other approaches to prepare vulnerable communities, especially young people, for natural hazards and human-induced environmental change include programs such as Plan International's "Child Centered Disaster Risk Reduction- Building Resilience Through Participation," and their "Weathering the Storm" project, focusing on integrating the needs of teenage girls with climate change adaptation and risk reduction. While minimizing global environmental and climate change is crucial, these and related programs that weave research with education, science with solutions offer the potential for addressing the "Grand Challenges" by better preparing for societal and environmental tipping points through a more balanced and integrated approach to addressing change."

  4. A method employing STM for the estimation of relative changes in the work function of modified metal tips

    Indian Academy of Sciences (India)

    R B Sharma; C P Vinod; G U Kulkarni

    2002-06-01

    – spectroscopy measurements using a scanning tunnelling microscope (STM) were carried out to determine the change in the work function of a W tip following one monolayer (1 ML) deposition of Ni and subsequent annealing at 700 K. The variation in the actual gap voltage obtained from the – data of the clean tip was used in the calculation. The estimated values of the change in work function, 0.16 eV and 0.59 eV, for as-deposited and annealed tips, respectively match closely with the reported values. The method is generally applicable to chemically modified metal tips.

  5. Beyond the Tipping Point: Issues of Racial Diversity in Magnet Schools Following Unitary Status

    Science.gov (United States)

    Smrekar, Claire

    2009-01-01

    This article uses qualitative case study methodology to examine why the racial composition of magnet schools in Nashville, Tennessee, has shifted to predominantly African American in the aftermath of unitary status. The article compares the policy contexts and parents' reasons for choosing magnet schools at two points in time--under court order…

  6. Structural changes in a Schiff base molecular assembly initiated by scanning tunneling microscopy tip

    Science.gov (United States)

    Tomak, A.; Bacaksiz, C.; Mendirek, G.; Sahin, H.; Hur, D.; Görgün, K.; Senger, R. T.; Birer, Ö.; Peeters, F. M.; Zareie, H. M.

    2016-08-01

    We report the controlled self-organization and switching of newly designed Schiff base (E)-4-((4-(phenylethynyl) benzylidene) amino) benzenethiol (EPBB) molecules on a Au (111) surface at room temperature. Scanning tunneling microscopy and spectroscopy (STM/STS) were used to image and analyze the conformational changes of the EPBB molecules. The conformational change of the molecules was induced by using the STM tip while increasing the tunneling current. The switching of a domain or island of molecules was shown to be induced by the STM tip during scanning. Unambiguous fingerprints of the switching mechanism were observed via STM/STS measurements. Surface-enhanced Raman scattering was employed, to control and identify quantitatively the switching mechanism of molecules in a monolayer. Density functional theory calculations were also performed in order to understand the microscopic details of the switching mechanism. These calculations revealed that the molecular switching behavior stemmed from the strong interaction of the EPBB molecules with the STM tip. Our approach to controlling intermolecular mechanics provides a path towards the bottom-up assembly of more sophisticated molecular machines.

  7. Structural changes in a Schiff base molecular assembly initiated by scanning tunneling microscopy tip.

    Science.gov (United States)

    Tomak, A; Bacaksiz, C; Mendirek, G; Sahin, H; Hur, D; Görgün, K; Senger, R T; Birer, Ö; Peeters, F M; Zareie, H M

    2016-08-19

    We report the controlled self-organization and switching of newly designed Schiff base (E)-4-((4-(phenylethynyl) benzylidene) amino) benzenethiol (EPBB) molecules on a Au (111) surface at room temperature. Scanning tunneling microscopy and spectroscopy (STM/STS) were used to image and analyze the conformational changes of the EPBB molecules. The conformational change of the molecules was induced by using the STM tip while increasing the tunneling current. The switching of a domain or island of molecules was shown to be induced by the STM tip during scanning. Unambiguous fingerprints of the switching mechanism were observed via STM/STS measurements. Surface-enhanced Raman scattering was employed, to control and identify quantitatively the switching mechanism of molecules in a monolayer. Density functional theory calculations were also performed in order to understand the microscopic details of the switching mechanism. These calculations revealed that the molecular switching behavior stemmed from the strong interaction of the EPBB molecules with the STM tip. Our approach to controlling intermolecular mechanics provides a path towards the bottom-up assembly of more sophisticated molecular machines. PMID:27378765

  8. Canine sense and sensibility: tipping points and response latency variability as an optimism index in a canine judgement bias assessment.

    Directory of Open Access Journals (Sweden)

    Melissa J Starling

    Full Text Available Recent advances in animal welfare science used judgement bias, a type of cognitive bias, as a means to objectively measure an animal's affective state. It is postulated that animals showing heightened expectation of positive outcomes may be categorised optimistic, while those showing heightened expectations of negative outcomes may be considered pessimistic. This study pioneers the use of a portable, automated apparatus to train and test the judgement bias of dogs. Dogs were trained in a discrimination task in which they learned to touch a target after a tone associated with a lactose-free milk reward and abstain from touching the target after a tone associated with water. Their judgement bias was then probed by presenting tones between those learned in the discrimination task and measuring their latency to respond by touching the target. A Cox's Proportional Hazards model was used to analyse censored response latency data. Dog and Cue both had a highly significant effect on latency and risk of touching a target. This indicates that judgement bias both exists in dogs and differs between dogs. Test number also had a significant effect, indicating that dogs were less likely to touch the target over successive tests. Detailed examination of the response latencies revealed tipping points where average latency increased by 100% or more, giving an indication of where dogs began to treat ambiguous cues as predicting more negative outcomes than positive ones. Variability scores were calculated to provide an index of optimism using average latency and standard deviation at cues after the tipping point. The use of a mathematical approach to assessing judgement bias data in animal studies offers a more detailed interpretation than traditional statistical analyses. This study provides proof of concept for the use of an automated apparatus for measuring cognitive bias in dogs.

  9. Canine sense and sensibility: tipping points and response latency variability as an optimism index in a canine judgement bias assessment.

    Science.gov (United States)

    Starling, Melissa J; Branson, Nicholas; Cody, Denis; Starling, Timothy R; McGreevy, Paul D

    2014-01-01

    Recent advances in animal welfare science used judgement bias, a type of cognitive bias, as a means to objectively measure an animal's affective state. It is postulated that animals showing heightened expectation of positive outcomes may be categorised optimistic, while those showing heightened expectations of negative outcomes may be considered pessimistic. This study pioneers the use of a portable, automated apparatus to train and test the judgement bias of dogs. Dogs were trained in a discrimination task in which they learned to touch a target after a tone associated with a lactose-free milk reward and abstain from touching the target after a tone associated with water. Their judgement bias was then probed by presenting tones between those learned in the discrimination task and measuring their latency to respond by touching the target. A Cox's Proportional Hazards model was used to analyse censored response latency data. Dog and Cue both had a highly significant effect on latency and risk of touching a target. This indicates that judgement bias both exists in dogs and differs between dogs. Test number also had a significant effect, indicating that dogs were less likely to touch the target over successive tests. Detailed examination of the response latencies revealed tipping points where average latency increased by 100% or more, giving an indication of where dogs began to treat ambiguous cues as predicting more negative outcomes than positive ones. Variability scores were calculated to provide an index of optimism using average latency and standard deviation at cues after the tipping point. The use of a mathematical approach to assessing judgement bias data in animal studies offers a more detailed interpretation than traditional statistical analyses. This study provides proof of concept for the use of an automated apparatus for measuring cognitive bias in dogs.

  10. Special Issue: Creating a Tipping Point--Strategic Human Resources in Higher Education

    Science.gov (United States)

    Evans, Alvin; Chun, Edna

    2012-01-01

    This monograph examines the emergence of strategic human resource (HR) practices in higher education at a time when the budgetary crisis in public higher education has never been more acute. The wave of financial pressures on public research universities today heralds the advent of an era of unprecedented change. Financial upheaval resulting from…

  11. Leadership beyond the Tipping Point: toward the Discovery of Inversions and Complementary Hypotheses

    OpenAIRE

    Cavarretta, Fabrice,; Hannah, Sean,; Piccolo, Ronald,; Uhl-Bien, Mary

    2015-01-01

    Leadership theories often include a contingency effect where the relationship between two or more variables is normally theorized to be monotonic, i.e., that it has a generally accepted direction—positive or negative—across the full range of the contingency variable. Most examinations of contingencies estimate how the monotonic relationship changes at mean, or near mean, levels of the moderator variable. We push the logic of moderation further to explore whether, for extra-ordinary values of ...

  12. Influence of the tip mass on the tip-sample interactions in TM-AFM

    International Nuclear Information System (INIS)

    This paper focuses on the influences of the tip mass ratio (the ratio of the tip mass to the cantilever mass), on the excitation of higher oscillation eigenmodes and also on the tip-sample interaction forces in tapping mode atomic force microscopy (TM-AFM). A precise model for the cantilever dynamics capable of accurate simulations is essential for the investigation of the tip mass effects on the interaction forces. In the present work, the finite element method (FEM) is used for modeling the AFM cantilever to consider the oscillations of higher eigenmodes oscillations. In addition, molecular dynamics (MD) is used to calculate precise data for the tip-sample force as a function of tip vertical position with respect to the sample. The results demonstrate that in the presence of nonlinear tip-sample interaction forces, the tip mass ratio plays a significant role in the excitations of higher eigenmodes and also in the normal force applied on the surface. Furthermore, it has been shown that the difference between responses of the FEM and point-mass models in different system operational conditions is highly affected by the tip mass ratio. -- Highlights: → A strong correlation exists between the tip mass ratio and the 18th harmonic amplitude. → Near the critical tip mass ratio a small change in the tip mass may lead to a significant force change. → Inaccuracy of the lumped model depends significantly on the tip mass ratio

  13. Linking Childhood Maltreatment with Girls' Internalizing Symptoms: Early Puberty as a Tipping Point.

    Science.gov (United States)

    Mendle, Jane; Leve, Leslie D; Van Ryzin, Mark; Natsuaki, Misaki N

    2014-12-01

    Early pubertal timing in girls is one of the most frequently replicated antecedents of adolescent emotional distress. Yet understanding the impact of pubertal timing in psychosocial development has presented something of a conundrum for developmentalists, as earlier physical maturation may often be preceded by a range of early adversities and life stressors. The present paper disentangles these associations by investigating childhood maltreatment, adolescent internalizing symptoms, and perceived pubertal timing in girls who were residing in foster care at study entry (N = 100, M = 11.54 years old at Time 1). Girls were assessed at two time points two years apart. There were no significant direct effects of maltreatment on internalizing symptoms; rather, childhood sexual abuse predicted earlier perceived pubertal development at study onset which, in turn, was associated with higher levels of internalizing symptomatology. These higher levels of internalizing symptoms persisted over the two years of the study. This distinctive role for early pubertal timing - even within a sample subject to stressors and risks which far exceed the developmental norm - confirms the unique salience of pubertal timing in emotional adjustment, and suggests that the heightened sexual circumstances of puberty may be especially disturbing for girls whose lives have already been traumatically disrupted by inappropriate and unwanted sexual experiences. PMID:25419091

  14. Tipping Points and the Accommodation of the Abuser: Ongoing Incestuous Abuse during Adulthood

    Directory of Open Access Journals (Sweden)

    Warwick Middleton

    2015-07-01

    Full Text Available Until recently the widespread reality of ongoing incestuous abuse during adulthood had attracted no systematic research. The scientific literature was limited to the occasional case study and brief anecdotal references. This minimal literature was supplemented by biographical works written by or about victims of this form of abuse, and by press reports. With the advent of the Josef Fritzl case there was a very marked increase in the press reporting of such abuse, which in turn provided a reference point for more fine-grained data collection and scientific reporting. This paper introduces the subject of prolonged incest via the lens of organised abuse, summarises research on incestuous abuse and draws on multiple clinical examples to elucidate the mechanisms by which such abuse merges with, or develops into, variations of organised abuse, including that centred on the family, on prostitution, or on that involving abuse networks. The abuse practices, the net-working, and the ploys used to avoid prosecution practiced by the father perpetrating ongoing incestuous abuse during adulthood have much in common with other variants of organised sexual abuse.

  15. The miraculous year 2010 in United States' gay rights law: Anomaly or tipping point?

    Directory of Open Access Journals (Sweden)

    Arthur S Leonard

    2011-05-01

    Full Text Available

    During 2010 a series of decisions by United States District Court judges appeared to mark a significant breakthrough in the ongoing struggle by sexual minorities in the United States to achieve legal equality through the removal of objectionable laws and policies.  Almost as if a dam had broken, there was a sudden rush of developments on three highly contested fronts: (1 the statutory ban on military service by openly gay individuals, (2 the exclusion from federal recognition for lawfully contracted same-sex marriages, and (3 a popularly enacted California state constitutional amendment taking away same-sex marriage rights that had previously been granted by a state supreme court decision. In each of these cases, the district courts declared the contested policy to be unconstitutional and ordered injunctive relief, placing in doubt the willingness of courts to continue crediting traditional arguments that had been successfully invoked by the government when defending these and similar policies in past cases. In this comment, the author argues that these decisions may work a fundamental change in the analysis of LGBT constitutional claims that portends significant progress towards achieving legal equality for sexual minorities in the United States.

  16. Microstructural changes induced near crack tip during corrosion fatigue tests in austenitic-ferritic steel.

    Science.gov (United States)

    Gołebiowski, B; Swiatnicki, W A; Gaspérini, M

    2010-03-01

    Microstructural changes occurring during fatigue tests of austenitic-ferritic duplex stainless steel (DSS) in air and in hydrogen-generating environment have been investigated. Hydrogen charging of steel samples during fatigue crack growth (FCG) tests was performed by cathodic polarization of specimens in 0.1M H(2)SO(4) aqueous solution. Microstructural investigations of specimens after FCG tests were carried out using transmission electron microscopy to reveal the density and arrangement of dislocations formed near crack tip. To determine the way of crack propagation in the microstructure, electron backscatter diffraction investigations were performed on fatigue-tested samples in both kinds of environment. To reveal hydrogen-induced phase transformations the atomic force microscopy was used. The above investigations allowed us to define the character of fatigue crack propagation and microstructural changes near the crack tip. It was found that crack propagation after fatigue tests in air is accompanied with plastic deformation; a high density of dislocations is observed at large distance from the crack. After fatigue tests performed during hydrogen charging the deformed zone containing high density of dislocations is narrow compared to that after fatigue tests in air. It means that hydrogenation leads to brittle character of fatigue crack propagation. In air, fatigue cracks propagate mostly transgranularly, whereas in hydrogen-generating environment the cracks have mixed transgranular/interfacial character. PMID:20500395

  17. Endocannabinoids, FOXO and the metabolic syndrome: redox, function and tipping point--the view from two systems.

    Science.gov (United States)

    Nunn, Alistair V W; Guy, Geoffrey W; Bell, Jimmy D

    2010-08-01

    The endocannabinoid system (ECS) was only 'discovered' in the 1990s. Since then, many new ligands have been identified, as well as many new intracellular targets--ranging from the PPARs, to mitochondria, to lipid rafts. It was thought that blocking the CB-1 receptor might reverse obesity and the metabolic syndrome. This was based on the idea that the ECS was dysfunctional in these conditions. This has met with limited success. The reason may be that the ECS is a homeostatic system, which integrates energy seeking and storage behaviour with resistance to oxidative stress. It could be viewed as having thrifty actions. Thriftiness is an innate property of life, which is programmed to a set point by both environment and genetics, resulting in an epigenotype perfectly adapted to its environment. This thrifty set point can be modulated by hormetic stimuli, such as exercise, cold and plant micronutrients. We have proposed that the physiological and protective insulin resistance that underlies thriftiness encapsulates something called 'redox thriftiness', whereby insulin resistance is determined by the ability to resist oxidative stress. Modern man has removed most hormetic stimuli and replaced them with a calorific sedentary lifestyle, leading to increased risk of metabolic inflexibility. We suggest that there is a tipping point where lipotoxicity in adipose and hepatic cells induces mild inflammation, which switches thrifty insulin resistance to inflammation-driven insulin resistance. To understand this, we propose that the metabolic syndrome could be seen from the viewpoint of the ECS, the mitochondrion and the FOXO group of transcription factors. FOXO has many thrifty actions, including increasing insulin resistance and appetite, suppressing oxidative stress and shifting the organism towards using fatty acids. In concert with factors such as PGC-1, they also modify mitochondrial function and biogenesis. Hence, the ECS and FOXO may interact at many points; one of which

  18. Optimal change-point estimation from indirect observations

    OpenAIRE

    Goldenshluger, A.; TSYBAKOV, A.; Zeevi, A.

    2006-01-01

    We study nonparametric change-point estimation from indirect noisy observations. Focusing on the white noise convolution model, we consider two classes of functions that are smooth apart from the change-point. We establish lower bounds on the minimax risk in estimating the change-point and develop rate optimal estimation procedures. The results demonstrate that the best achievable rates of convergence are determined both by smoothness of the function away from the change-point and by the degr...

  19. The tipping point

    DEFF Research Database (Denmark)

    Guns, Raf; Lioma, Christina; Larsen, Birger

    2012-01-01

    One of the best known measures of information retrieval (IR) performance is the F-score, the harmonic mean of precision and recall. In this article we show that the curve of the F-score as a function of the number of retrieved items is always of the same shape: a fast concave increase to a maximu...

  20. Change-point estimation for censored regression model

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    In this paper, we consider the change-point estimation in the censored regression model assuming that there exists one change point. A nonparametric estimate of the change-point is proposed and is shown to be strongly consistent. Furthermore, its convergence rate is also obtained.

  1. Energy Change due to Off-Fault Damage Evolution associated with Dynamic Fault Tip Growth

    Science.gov (United States)

    Suzuki, T.

    2010-12-01

    We theoretically study off-fault damage evolution effects on dynamic earthquake rupture, especially from a standpoint of energy change in a whole system. The importance of off-fault inelastic energy loss due to damage on dynamic earthquake rupture has attracted interests of many researchers in terms of, for example, rupture velocity reduction and crack tip growth cessation. The damage effect is found to be important on dynamic earthquake slip behavior in terms of porosity increase also in a series of our previous studies, Suzuki and Yamashita (2007; 2008; 2009; 2010). The mathematical formulation of Murakami and Kamiya (1997) is assumed in the present study; the damage tensor D is used to describe damage state in a medium. Damage, which consists of microcracks in a medium, has direction (defined as normal to the crack surface) and the magnitude (crack size), so that a scalar damage variable is insufficient to describe the damage state. We first analytically derive the equation system including the damage tensor and describing energy change in a whole system due to any dynamic elastic and inelastic deformation processes such as macroscopic crack extension and damage evolution. The change in the summation of strain and kinetic energies and damage energy is found to be equal to the summation of energy flowing out of the medium through the boundary and energy turning to heat and irreversibly lost based on the analytical expression; the damage energy is associated with surface energy released by damage evolution. The damage energy is confirmed to be equal to the summation of the loss in strain energy due to change in the elastic moduli and irreversibly lost energy. A mode III crack embedded in a medium causing damage is then assumed to study the off-fault damage effects on dynamic earthquake rupture. Spontaneous crack tip growth with the Coulomb fracture criterion is assumed and in such a case the rupture velocity can be sufficiently smaller than the terminal velocity

  2. Mitosis and microtubule organizational changes in rice root-tip cells

    Institute of Scientific and Technical Information of China (English)

    XUSHIXIONG(SYZEE); CHUNGUILI; CHENGZHU

    1993-01-01

    The pattern of change of the microtubule cytoskeleton of the root-tip cells of rice during mitosis was studied using immunofluorescence technic and confocal laser scanning microscopy. All the major stages of ceil division including preprophase, prophase, metaphase, anaphase and telophase were observed. The most significant finding was that in the preprophase cells microtubules radiating from the nuclear surface to the cortex were frequently seen. During development these microtubules became closely associated with the preprophase band and prophase spindie indicating that the microtubules radiating from the nuclear surface, the preprophase band and the prophazc spindle were structurally and functionally closely related to each other. Granule-like anchorage sites for the radiating microtubules at the muclear surface were often seen and the possibility that these gramle-like anchorage sites might represent the microtubule organizing centres was discussed.

  3. Dramatic changes in ectomycorrhizal community composition, root tip abundance and mycelial production along a stand-scale nitrogen deposition gradient

    DEFF Research Database (Denmark)

    Kjøller, Rasmus; Nilsson, Lars Ola; Hansen, Karin;

    2012-01-01

    • Nitrogen (N) availability is known to influence ectomycorrhizal fungal components, such as fungal community composition, biomass of root tips and production of mycelia, but effects have never been demonstrated within the same forest. • We measured concurrently the abundance of ectomycorrhizal...... root tips and the production of external mycelia, and explored the changes in the ectomycorrhizal community composition, across a stand-scale N deposition gradient (from 27 to 43 kg N ha¿¹ yr¿¹) at the edge of a spruce forest. The N status was affected along the gradient as shown by a range of N...... availability indices. • Ectomycorrhizal root tip abundance and mycelial production decreased five and 10-fold, respectively, with increasing N deposition. In addition, the ectomycorrhizal fungal community changed and the species richness decreased. The changes were correlated with the measured indices of N...

  4. It's all change at the visit points

    CERN Multimedia

    Laëtitia Pedroso

    2011-01-01

    58,000 people visited CERN in 2010. In spite of this success, the Organization has plans to review the installations at the various visit points with a view to making the links between them clearer and, above all, making tours of the Laboratory more spectacular.   CERN Control Centre. The permanent exhibition in the Globe of Science and Innovation, the "Universe of Particles", attracts large numbers of visitors. A high-tech venue offering an overview of CERN's research goals, tools and impact throughout the world, the Globe acts as a showcase for the Laboratory. "The Globe is an ideal place to start a tour of CERN. After experiencing a virtual experiment at the heart of the Universe, visitors are keen to find out what's behind it all, to know more about the research we do here at CERN.When it was still possible to see the LHC detectors, visitors were bowled over by their huge size. To continue to surprise them to the same extent, we are planning to reorganise the visit...

  5. Soft tissue injury related to choice of entry point in antegrade femoral nailing : piriform fossa or greater trochanter tip

    NARCIS (Netherlands)

    Moein, CMA; Verhofstad, MHJ; Bleys, RLAW; van der Werken, C

    2005-01-01

    Intramedullary nailing through the piriform fossa results in some cases in toss of abduction strength and persistent pain. Nail insertion at the tip of the greater trochanter may be favourable. The aim of this study was to assess (possible) iatrogenic injury to the abductor and external rotator musc

  6. Inference of change-point in single index models

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Single index models are widely used in medicine, econometrics and some other fields. In this paper, we consider the inference of a change point problem in single index models. Based on density-weighted average derivative estimation (ADE) method, we propose a statistic to test whether a change point exists or not. The null distribution of the test statistic is obtained using a permutation technique. The permuted statistic is rigorously shown to have the same distribution in the limiting sense under both null and alternative hypotheses. After the null hypothesis of no change point is rejected, an ADE-based estimate of the change point is proposed under assumption that the change point is unique. A simulation study confirms the theoretical results.

  7. Scalability of valence change memory: From devices to tip-induced filaments

    Science.gov (United States)

    Celano, U.; Fantini, A.; Degraeve, R.; Jurczak, M.; Goux, L.; Vandervorst, W.

    2016-08-01

    Since the early days of the investigation on resistive switching (RS), the independence of the ON-state resistance with actual cell area has been a trademark of filamentary-switching. However, with the continuous downscaling of the memory cell down to 10 x 10 nm2 and below, the persistence of this phenomena raises intriguing questions on the conductive filaments (CFs) and its dimensions. Particularly, the cell functionality demonstrated at relatively high switching current (> 100 μA) implies a high current density (> 106 A/cm2) inside a CF supposedly confined in few hundreds on nm3. We previously demonstrated a methodology for the direct observation of CFs in integrated devices namely scalpel SPM, which overcomes most of the characterization challenges imposed by the device structure and the small CF lateral dimensions. In this letter, we use scalpel SPM to clarify the scaling potential of HfO2-based valence change memory (VCM) by characterization of CFs programmed at relatively high switching current and by AFM tip-induced RS experiments. Besides the demonstration of a remarkable scaling potential for the VCM technology, our results are also used to clarify the present understanding on the AFM-based experiments.

  8. Changes in the proteomic and metabolic profiles of Beta vulgaris root tips in response to iron deficiency and resupply

    Directory of Open Access Journals (Sweden)

    Álvarez-Fernández Ana

    2010-06-01

    Full Text Available Abstract Background Plants grown under iron deficiency show different morphological, biochemical and physiological changes. These changes include, among others, the elicitation of different strategies to improve the acquisition of Fe from the rhizosphere, the adjustment of Fe homeostasis processes and a reorganization of carbohydrate metabolism. The application of modern techniques that allow the simultaneous and untargeted analysis of multiple proteins and metabolites can provide insight into multiple processes taking place in plants under Fe deficiency. The objective of this study was to characterize the changes induced in the root tip proteome and metabolome of sugar beet plants in response to Fe deficiency and resupply. Results Root tip extract proteome maps were obtained by 2-D isoelectric focusing polyacrylamide gel electrophoresis, and approximately 140 spots were detected. Iron deficiency resulted in changes in the relative amounts of 61 polypeptides, and 22 of them were identified by mass spectrometry (MS. Metabolites in root tip extracts were analyzed by gas chromatography-MS, and more than 300 metabolites were resolved. Out of 77 identified metabolites, 26 changed significantly with Fe deficiency. Iron deficiency induced increases in the relative amounts of proteins and metabolites associated to glycolysis, tri-carboxylic acid cycle and anaerobic respiration, confirming previous studies. Furthermore, a protein not present in Fe-sufficient roots, dimethyl-8-ribityllumazine (DMRL synthase, was present in high amounts in root tips from Fe-deficient sugar beet plants and gene transcript levels were higher in Fe-deficient root tips. Also, a marked increase in the relative amounts of the raffinose family of oligosaccharides (RFOs was observed in Fe-deficient plants, and a further increase in these compounds occurred upon short term Fe resupply. Conclusions The increases in DMRL synthase and in RFO sugars were the major changes induced by Fe

  9. Modified estimators for the change point in hazard function

    Science.gov (United States)

    Karasoy, Durdu; Kadilar, Cem

    2009-07-01

    We propose the consistent estimators for the change point in hazard function by improving the estimators in [A.P. Basu, J.K. Ghosh, S.N. Joshi, On estimating change point in a failure rate, in: S.S. Gupta, J.O. Berger (Eds.), Statistical Decision Theory and Related Topics IV, vol. 2, Springer-Verlag, 1988, pp. 239-252] and [H.T. Nguyen, G.S. Rogers, E.A. Walker, Estimation in change point hazard rate model, Biometrika 71 (1984) 299-304]. By a simulation study, we show that the proposed estimators are more efficient than the original estimators in many cases.

  10. Asymptotic Distribution of the Jump Change-Point Estimator

    Institute of Scientific and Technical Information of China (English)

    Changchun TAN; Huifang NIU; Baiqi MIAO

    2012-01-01

    The asymptotic distribution of the change-point estimator in a jump changepoint model is considered.For the jump change-point model Xi =a + θI{[nTo] < i ≤n} + εi,where εi (i =1,…,n) are independent identically distributed random variables with Eεi=0 and Var(εi) < oo,with the help of the slip window method,the asymptotic distribution of the jump change-point estimator (T) is studied under the condition of the local alternative hypothesis.

  11. Change detection in polarimetric SAR data over several time points

    DEFF Research Database (Denmark)

    Conradsen, Knut; Nielsen, Allan Aasbjerg; Skriver, Henning

    2014-01-01

    A test statistic for the equality of several variance-covariance matrices following the complex Wishart distribution is introduced. The test statistic is applied successfully to detect change in C-band EMISAR polarimetric SAR data over four time points....

  12. Fast Change Point Detection for Electricity Market Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Berkeley, UC; Gu, William; Choi, Jaesik; Gu, Ming; Simon, Horst; Wu, Kesheng

    2013-08-25

    Electricity is a vital part of our daily life; therefore it is important to avoid irregularities such as the California Electricity Crisis of 2000 and 2001. In this work, we seek to predict anomalies using advanced machine learning algorithms. These algorithms are effective, but computationally expensive, especially if we plan to apply them on hourly electricity market data covering a number of years. To address this challenge, we significantly accelerate the computation of the Gaussian Process (GP) for time series data. In the context of a Change Point Detection (CPD) algorithm, we reduce its computational complexity from O($n^{5}$) to O($n^{2}$). Our efficient algorithm makes it possible to compute the Change Points using the hourly price data from the California Electricity Crisis. By comparing the detected Change Points with known events, we show that the Change Point Detection algorithm is indeed effective in detecting signals preceding major events.

  13. Nuclear changes induced by the nematode Xiphinema diversicaudatum in root-tips of strawberry.

    Science.gov (United States)

    Griffiths, B S; Robertson, W M

    1984-03-01

    Feeding by the nematode X. diversicaudatum caused a progressive increase in the DNA content and size of strawberry nuclei. After four days feeding, nuclei had DNA values intermediate between 8C and 16C and had increased in size from a mean of 17 micron2 for control root tips to 49 micron2. Multinucleate cells were present after two and four days feeding. There were no ultrastructural differences in the composition of nuclei from control and parasitized root tips, but strawberry nuclei consisted mainly of dispersed chromatin whereas ryegrass nuclei contained a large proportion of condensed chromatin.

  14. Change-point in stochastic design regression and the bootstrap

    OpenAIRE

    Seijo, Emilio; Sen, Bodhisattva

    2011-01-01

    In this paper we study the consistency of different bootstrap procedures for constructing confidence intervals (CIs) for the unique jump discontinuity (change-point) in an otherwise smooth regression function in a stochastic design setting. This problem exhibits nonstandard asymptotics and we argue that the standard bootstrap procedures in regression fail to provide valid confidence intervals for the change-point. We propose a version of smoothed bootstrap, illustrate its remarkable finite sa...

  15. Tipping elements and climate-economic shocks: Pathways toward integrated assessment

    Science.gov (United States)

    Kopp, Robert E.; Shwom, Rachael L.; Wagner, Gernot; Yuan, Jiacan

    2016-08-01

    The literature on the costs of climate change often draws a link between climatic "tipping points" and large economic shocks, frequently called "catastrophes." The phrase "tipping points" in this context can be misleading. In popular and social scientific discourse, "tipping points" involve abrupt state changes. For some climatic "tipping points," the commitment to a state change may occur abruptly, but the change itself may be rate-limited and take centuries or longer to realize. Additionally, the connection between climatic "tipping points" and economic losses is tenuous, although emerging empirical and process-model-based tools provide pathways for investigating it. We propose terminology to clarify the distinction between "tipping points" in the popular sense, the critical thresholds exhibited by climatic and social "tipping elements," and "economic shocks." The last may be associated with tipping elements, gradual climate change, or nonclimatic triggers. We illustrate our proposed distinctions by surveying the literature on climatic tipping elements, climatically sensitive social tipping elements, and climate-economic shocks, and we propose a research agenda to advance the integrated assessment of all three.

  16. Nonparametric Multiple Change Point Analysis of the Global Financial Crisis

    NARCIS (Netherlands)

    D.E. Allen (David); R.J. Powell (Robert); A.K. Singh (Abhay)

    2013-01-01

    textabstractThis paper presents an application of a recently developed approach by Matteson and James (2012) for the analysis of change points in a data set, namely major financial market indices converted to financial return series. The general problem concerns the inference of a change in the dist

  17. Nonparametric Inference in a Simple Change-point Model

    Institute of Scientific and Technical Information of China (English)

    Zhan Feng WANG; Yao Hua WU; Lin Cheng ZHAO

    2008-01-01

    In this paper, we consider a change point model allowing at most one change, X( in) =f( in) + e( in ), where f(t) = α + θI(t0,1)(t), 0 ≤ t ≤ 1, {e( 1n ), . . . , e( nn )} is a sequence of I.I.d. Random variables distributed as e with 0 being the median of e. For this change point model, hypothesis test problem about the change-point t0 is studied and a test statistic is constructed. Furthermore, a nonparametric estimator of to is proposed and shown to be strongly consistent. Finally, we give an estimator of jump θ and obtain it's asymptotic property. Performance of the proposed approach is investigated by extensive simulation studies.

  18. Change-Point Estimates in Longitudinal Binary Data

    Institute of Scientific and Technical Information of China (English)

    WU Xiaoru; YANG Ying

    2008-01-01

    Most change-point models assume that the response is continuous or cross sectional binary.However,in many public health problems,the data is longitudinal binary.There are few studies of change-point problems for longitudinal outcomes.This paper describes a flexible change-point model which includes random-effects and takes into account the difference between various individuals in longitudinal binary data.A transition function is used to make the linear-linear logistic model differentiable at the change-point.The location of the change-point is estimated using the maximum likelihood method.Adjust-ment of the transition parameter from zero to one controls the sharpness of the transition.The performance of this estimation procedure is illustrated with simulations using SAS/proc nlmixed and a detailed analysis of data relating hormone levels and ovary functions based on data from the Obstetrics and Gynecology Hospi-tal,Medical Center of Fudan University.

  19. Street environment change detection from mobile laser scanning point clouds

    Science.gov (United States)

    Xiao, Wen; Vallet, Bruno; Brédif, Mathieu; Paparoditis, Nicolas

    2015-09-01

    Mobile laser scanning (MLS) has become a popular technique for road inventory, building modelling, infrastructure management, mobility assessment, etc. Meanwhile, due to the high mobility of MLS systems, it is easy to revisit interested areas. However, change detection using MLS data of street environment has seldom been studied. In this paper, an approach that combines occupancy grids and a distance-based method for change detection from MLS point clouds is proposed. Unlike conventional occupancy grids, our occupancy-based method models space based on scanning rays and local point distributions in 3D without voxelization. A local cylindrical reference frame is presented for the interpolation of occupancy between rays according to the scanning geometry. The Dempster-Shafer theory (DST) is utilized for both intra-data evidence fusion and inter-data consistency assessment. Occupancy of reference point cloud is fused at the location of target points and then the consistency is evaluated directly on the points. A point-to-triangle (PTT) distance-based method is combined to improve the occupancy-based method. Because it is robust to penetrable objects, e.g. vegetation, which cause self-conflicts when modelling occupancy. The combined method tackles irregular point density and occlusion problems, also eliminates false detections on penetrable objects.

  20. CPAP Tips

    Science.gov (United States)

    ... Queue Queue __count__/__total__ Find out why Close CPAP Tips from FDA USFoodandDrugAdmin Subscribe Subscribed Unsubscribe 15, ... apnea and use a continuous positive airway pressure (CPAP) device when sleeping? Here are some tips from ...

  1. Growth Curve Analysis and Change-Points Detection in Extremes

    KAUST Repository

    Meng, Rui

    2016-05-15

    The thesis consists of two coherent projects. The first project presents the results of evaluating salinity tolerance in barley using growth curve analysis where different growth trajectories are observed within barley families. The study of salinity tolerance in plants is crucial to understanding plant growth and productivity. Because fully-automated smarthouses with conveyor systems allow non-destructive and high-throughput phenotyping of large number of plants, it is now possible to apply advanced statistical tools to analyze daily measurements and to study salinity tolerance. To compare different growth patterns of barley variates, we use functional data analysis techniques to analyze the daily projected shoot areas. In particular, we apply the curve registration method to align all the curves from the same barley family in order to summarize the family-wise features. We also illustrate how to use statistical modeling to account for spatial variation in microclimate in smarthouses and for temporal variation across runs, which is crucial for identifying traits of the barley variates. In our analysis, we show that the concentrations of sodium and potassium in leaves are negatively correlated, and their interactions are associated with the degree of salinity tolerance. The second project studies change-points detection methods in extremes when multiple time series data are available. Motived by the scientific question of whether the chances to experience extreme weather are different in different seasons of a year, we develop a change-points detection model to study changes in extremes or in the tail of a distribution. Most of existing models identify seasons from multiple yearly time series assuming a season or a change-point location remains exactly the same across years. In this work, we propose a random effect model that allows the change-point to vary from year to year, following a given distribution. Both parametric and nonparametric methods are developed

  2. Open Source Software Reliability Growth Model by Considering Change- Point

    Directory of Open Access Journals (Sweden)

    Mashaallah Basirzadeh

    2012-01-01

    Full Text Available The modeling technique for Software Reliability is reaching its prosperity. Software reliability growth models have been used extensively for closed source software. The design and development of open source software (OSS is different from closed source software. We observed some basic characteristics for open source software like (i more instructions execution and code coverage taking place with respect to time, (ii release early, release often (iii frequent addition of patches (iv heterogeneity in fault density and effort expenditure (v Frequent release activities seem to have changed the bug dynamics significantly (vi Bug reporting on bug tracking system drastically increases and decreases. Due to this reason bug reported on bug tracking system keeps an irregular state and fluctuations. Therefore, fault detection/removal process can not be smooth and may be changed at some time point called change-point. In this paper, an instructions executed dependent software reliability growth model has been developed by considering change-point in order to cater diverse and huge user profile, irregular state of bug tracking system and heterogeneity in fault distribution. We have analyzed actual software failure count data to show numerical examples of software reliability assessment for the OSS. We also compare our model with the conventional in terms of goodness-of-fit for actual data. We have shown that the proposed model can assist improvement of quality for OSS systems developed under the open source project.

  3. Signal detection using change point analysis in postmarket surveillance†

    OpenAIRE

    Xu, Zhiheng; Kass-Hout, Taha; Anderson-Smits, Colin; Gray, Gerry

    2015-01-01

    Purpose Signal detection methods have been used extensively in postmarket surveillance to identify elevated risks of adverse events associated with medical products (drugs, vaccines, and devices). However, current popular disproportionality methods ignore useful information such as trends when the data are aggregated over time for signal detection. Methods In this paper, we applied change point analysis (CPA) to trend analysis of medical products in a spontaneous adverse event reporting syste...

  4. Gaussian processes for state space models and change point detection

    OpenAIRE

    Turner, Ryan Darby

    2012-01-01

    This thesis details several applications of Gaussian processes (GPs) for enhanced time series modeling. We first cover different approaches for using Gaussian processes in time series problems. These are extended to the state space approach to time series in two different problems. We also combine Gaussian processes and Bayesian online change point detection (BOCPD) to increase the generality of the Gaussian process time series methods. These methodologies are evaluated on predict...

  5. The tipping point: Value differences and parallel dorsal-ventral frontal circuits gating human approach-avoidance behavior.

    Science.gov (United States)

    Schlund, Michael W; Brewer, Adam T; Magee, Sandy K; Richman, David M; Solomon, Scott; Ludlum, MaDonna; Dymond, Simon

    2016-08-01

    Excessive avoidance and diminished approach behavior are both prominent features of anxiety, trauma and stress related disorders. Despite this, little is known about the neuronal mechanisms supporting gating of human approach-avoidance behavior. Here, we used functional magnetic resonance imaging (fMRI) to track dorsal anterior cingulate and medial prefrontal (dACC/dmPFC) activation along an approach-avoidance continuum to assess sensitivity to competing appetitive and aversive contingencies and correspondence with behavior change. Behavioral and fMRI experiments were conducted using a novel approach-avoidance task where a monetary reward appeared in the presence of a conditioned stimulus (CS), or threat, that signaled increasing probability of unconditioned stimulus (US) delivery. Approach produced the reward or probabilistic US, while avoidance prevented US delivery, and across trials, reward remained fixed while the CS threat level varied unpredictably. Increasing the CS threat level (i.e., US probability) produced the desired approach-avoidance transition and inverted U-shaped changes in decision times, electrodermal activity and activation in pregenual ACC, dACC/dmPFC, striatum, anterior insula and inferior frontal regions. Conversely, U-shaped changes in activation were observed in dorsolateral and ventromedial prefrontal cortex and bimodal changes in the orbitofrontal and ventral hippocampus. These new results show parallel dorsal-ventral frontal circuits support gating of human approach-avoidance behavior where dACC/dmPFC signals inversely correlate with value differences between approach and avoidance contingencies while ventral frontal signals correlate with the value of predictable outcomes. Our findings provide an important bridge between basic research on brain mechanisms of value-guided decision-making and value-focused clinical theories of anxiety and related interventions.

  6. The tipping point: Value differences and parallel dorsal-ventral frontal circuits gating human approach-avoidance behavior.

    Science.gov (United States)

    Schlund, Michael W; Brewer, Adam T; Magee, Sandy K; Richman, David M; Solomon, Scott; Ludlum, MaDonna; Dymond, Simon

    2016-08-01

    Excessive avoidance and diminished approach behavior are both prominent features of anxiety, trauma and stress related disorders. Despite this, little is known about the neuronal mechanisms supporting gating of human approach-avoidance behavior. Here, we used functional magnetic resonance imaging (fMRI) to track dorsal anterior cingulate and medial prefrontal (dACC/dmPFC) activation along an approach-avoidance continuum to assess sensitivity to competing appetitive and aversive contingencies and correspondence with behavior change. Behavioral and fMRI experiments were conducted using a novel approach-avoidance task where a monetary reward appeared in the presence of a conditioned stimulus (CS), or threat, that signaled increasing probability of unconditioned stimulus (US) delivery. Approach produced the reward or probabilistic US, while avoidance prevented US delivery, and across trials, reward remained fixed while the CS threat level varied unpredictably. Increasing the CS threat level (i.e., US probability) produced the desired approach-avoidance transition and inverted U-shaped changes in decision times, electrodermal activity and activation in pregenual ACC, dACC/dmPFC, striatum, anterior insula and inferior frontal regions. Conversely, U-shaped changes in activation were observed in dorsolateral and ventromedial prefrontal cortex and bimodal changes in the orbitofrontal and ventral hippocampus. These new results show parallel dorsal-ventral frontal circuits support gating of human approach-avoidance behavior where dACC/dmPFC signals inversely correlate with value differences between approach and avoidance contingencies while ventral frontal signals correlate with the value of predictable outcomes. Our findings provide an important bridge between basic research on brain mechanisms of value-guided decision-making and value-focused clinical theories of anxiety and related interventions. PMID:27153979

  7. Si2Sb2Te5 phase change material studied by an atomic force microscope nano-tip

    Institute of Scientific and Technical Information of China (English)

    Liu Yanbo; Zhang Ting; Niu Xiaoming; Song Zhitang; Min Guoquan; Zhang Jing; Zhou Weimin; Wan Yongzhong; Zhang Jianping; Li Xiaoli; Feng Songlin

    2009-01-01

    The Si2Sb2Te5 phase change material has been studied by applying a nano-tip (30 nm in diameter) on an atomic force microscopy system. Memory switching from a high resistance state to a low resistance state has been achieved, with a resistance change of about 1000 times. In a typical Ⅰ-Ⅴ curve, the current increases significantly after the voltage exceeds~4.3 V. The phase transformation of a Si2Sb2Te5 film was studied in situ by means of in situ X-ray diffraction and temperature dependent resistance measurements. The thermal stability of Si2Sb2Te5 and Ge2Sb2Te5 was characterized and compared as well.

  8. Effects of tail docking and docking length on neuroanatomical changes in healed tail tips of pigs.

    Science.gov (United States)

    Herskin, M S; Thodberg, K; Jensen, H E

    2015-04-01

    In pig production, piglets are tail docked at birth in order to prevent tail biting later in life. In order to examine the effects of tail docking and docking length on the formation of neuromas, we used 65 pigs and the following four treatments: intact tails (n=18); leaving 75% (n=17); leaving 50% (n=19); or leaving 25% (n=11) of the tail length on the pigs. The piglets were docked between day 2 and 4 after birth using a gas-heated apparatus, and were kept under conventional conditions until slaughter at 22 weeks of age, where tails were removed and examined macroscopically and histologically. The tail lengths and diameters differed at slaughter (lengths: 30.6±0.6; 24.9±0.4; 19.8±0.6; 8.7±0.6 cm; Ptail diameter: 0.5±0.03; 0.8±0.02; 1.0±0.03; 1.4±0.04 cm; Ptails with neuromas (64 v. 0%; Ptail (1.0±0.2 v. 0; Ptail docking piglets using hot-iron cautery causes formation of neuromas in the outermost part of the tail tip. The presence of neuromas might lead to altered nociceptive thresholds, which need to be confirmed in future studies. PMID:25482535

  9. Freezing Point Depressions of Phase Change CO2 Solvents

    DEFF Research Database (Denmark)

    Arshad, Muhammad Waseem; Fosbøl, Philip Loldrup; von Solms, Nicolas;

    2013-01-01

    Freezing point depressions (FPD) in phase change solvents containing 2-(diethylamino)ethanol (DEEA) and 3-(methylamino)propylamine (MAPA) were measured using a modified Beckmann apparatus. The measurements were performed for the binary aqueous DEEA and MAPA solutions, respectively......, in the concentration ranges of (0 to 55) mass percent and (0 to 32.5) mass percent of amine. For the ternary aqueous DEEA–MAPA solutions, freezing points were measured for 5:1, 3:1, 1:1, 1:3, and 1:5 molar ratios of DEEA/MAPA. The FPD method was extended for easy and accurate measurement of freezing points in the CO2...... loaded systems. It is based on saturation of the solution by CO2 and then dilution by using a batch of the original unloaded solution in order to get the solutions with different CO2 loadings. Freezing point measurements were then carried out for (12, 20, 30, and 33) mass percent DEEA solutions and (10...

  10. Changes in electrogustometry thresholds, tongue tip vascularization, density and form of the fungiform papillae in smokers.

    Science.gov (United States)

    Pavlidis, Pavlos; Gouveris, Charalampos; Kekes, Georgios; Maurer, Jan

    2014-08-01

    The objective of this study was to evaluate differences in gustatory function in smokers of both sexes and identify any differences in the shape, density and vascularisation of the fungiform papillae (fPap) of smokers' tongue. Additional aim was to investigate any relation between the age, pack years and differences in shape, density, vascularization of fPap and sex. In 166 smokers (81 males, 85 females, age range 20-80 years), divided in age groups, electrogustometry (EGM) thresholds at the chorda tympani area, at the soft palate area and at the area of the vallate papillae were recorded bilaterally. Morphology and density of the fPap and blood vessels' density and morphology at the tip of the tongue were examined using contact endoscopy (CE). EGM thresholds of all smoking subjects tended to increase compared to the non-smoking participants. Morphology, vascularization and density of fPap were found to be worse in smokers than in non-smokers. Interestingly, some participants, despite having increased number of pack years, tended to have almost similar EGM thresholds with non-smoking subjects of the same age group. Smoking tends to affect density, morphology and vascularization of the fPap. There is a correlation between the duration of smoking (pack years) and the afore-mentioned parameters. The use of τ-Kendall criterion provided useful information about the different correlation between the EGM thresholds and vascularization, the EGM thresholds and morphology of fPap and EGM thresholds and density of fPap. The majority of smokers had elevated EGM thresholds compared to non-smokers. Smoking is an important factor which can lead to decreased taste acuity. The combination of methods, such as EGM and CE, can provide useful information about the morphology and function of taste buds. Of interest, women are less affected than men, irrespective of the age group.

  11. Nuclear changes induced by the nematodes Xiphinema diversicaudatum and Longidorus elongatus in root-tips of perennial ryegrass, Lolium perenne.

    Science.gov (United States)

    Griffiths, B S; Robertson, W M; Trudgill, D L

    1982-09-01

    The DNA content and size of individual nuclei from galls of perennial ryegrass root-tips induced by X. diversicaudatum and L. elongatus were measured. Feeding by X. diversicaudatum increased the DNA content of the nuclei by varying amounts. No regular doubling pattern of the DNA content was discernible. The DNA values varied up to between 32-64C. Generally the size of the nuclei was not increased, although some were larger than control nuclei. The modified nuclei probably have an altered metabolic function, which increases the food value of the gall to the nematode. Some bi-nucleate cells were also observed, which probably result from mitosis without cytokinesis. A preliminary examination of nuclei from galls induced by L. elongatus revealed similar nuclear changes, but no bi-nucleate cells were found.

  12. Evolutionary Sequential Monte Carlo Samplers for Change-Point Models

    Directory of Open Access Journals (Sweden)

    Arnaud Dufays

    2016-03-01

    Full Text Available Sequential Monte Carlo (SMC methods are widely used for non-linear filtering purposes. However, the SMC scope encompasses wider applications such as estimating static model parameters so much that it is becoming a serious alternative to Markov-Chain Monte-Carlo (MCMC methods. Not only do SMC algorithms draw posterior distributions of static or dynamic parameters but additionally they provide an estimate of the marginal likelihood. The tempered and time (TNT algorithm, developed in this paper, combines (off-line tempered SMC inference with on-line SMC inference for drawing realizations from many sequential posterior distributions without experiencing a particle degeneracy problem. Furthermore, it introduces a new MCMC rejuvenation step that is generic, automated and well-suited for multi-modal distributions. As this update relies on the wide heuristic optimization literature, numerous extensions are readily available. The algorithm is notably appropriate for estimating change-point models. As an example, we compare several change-point GARCH models through their marginal log-likelihoods over time.

  13. Vehicle Localization by LIDAR Point Correlation Improved by Change Detection

    Science.gov (United States)

    Schlichting, A.; Brenner, C.

    2016-06-01

    LiDAR sensors are proven sensors for accurate vehicle localization. Instead of detecting and matching features in the LiDAR data, we want to use the entire information provided by the scanners. As dynamic objects, like cars, pedestrians or even construction sites could lead to wrong localization results, we use a change detection algorithm to detect these objects in the reference data. If an object occurs in a certain number of measurements at the same position, we mark it and every containing point as static. In the next step, we merge the data of the single measurement epochs to one reference dataset, whereby we only use static points. Further, we also use a classification algorithm to detect trees. For the online localization of the vehicle, we use simulated data of a vertical aligned automotive LiDAR sensor. As we only want to use static objects in this case as well, we use a random forest classifier to detect dynamic scan points online. Since the automotive data is derived from the LiDAR Mobile Mapping System, we are able to use the labelled objects from the reference data generation step to create the training data and further to detect dynamic objects online. The localization then can be done by a point to image correlation method using only static objects. We achieved a localization standard deviation of about 5 cm (position) and 0.06° (heading), and were able to successfully localize the vehicle in about 93 % of the cases along a trajectory of 13 km in Hannover, Germany.

  14. VEHICLE LOCALIZATION BY LIDAR POINT CORRELATION IMPROVED BY CHANGE DETECTION

    Directory of Open Access Journals (Sweden)

    A. Schlichting

    2016-06-01

    Full Text Available LiDAR sensors are proven sensors for accurate vehicle localization. Instead of detecting and matching features in the LiDAR data, we want to use the entire information provided by the scanners. As dynamic objects, like cars, pedestrians or even construction sites could lead to wrong localization results, we use a change detection algorithm to detect these objects in the reference data. If an object occurs in a certain number of measurements at the same position, we mark it and every containing point as static. In the next step, we merge the data of the single measurement epochs to one reference dataset, whereby we only use static points. Further, we also use a classification algorithm to detect trees. For the online localization of the vehicle, we use simulated data of a vertical aligned automotive LiDAR sensor. As we only want to use static objects in this case as well, we use a random forest classifier to detect dynamic scan points online. Since the automotive data is derived from the LiDAR Mobile Mapping System, we are able to use the labelled objects from the reference data generation step to create the training data and further to detect dynamic objects online. The localization then can be done by a point to image correlation method using only static objects. We achieved a localization standard deviation of about 5 cm (position and 0.06° (heading, and were able to successfully localize the vehicle in about 93 % of the cases along a trajectory of 13 km in Hannover, Germany.

  15. Principle of Sports Tipping Point and Its Inspiration for The Nan Jing Youth Olympic Games%体育引爆流行的机制及其对南京青奥会的启示

    Institute of Scientific and Technical Information of China (English)

    罗立平

    2014-01-01

    运用文献分析、归纳演绎等研究方法,对体育引爆流行的历史事实进行了梳理,探讨了体育引爆流行的归因及机制。本文认为,南京青奥会可以借助体育引爆流行的法则进行城市营销,并初步提出了南京青奥会引爆流行的设想。%The history of Sports Tipping Point was reviewed in this paper by the method of literature analysis, induction and deduction. It discussed the attribution and mechanism of Sports Tipping Point. This paper proposed that, The Nan Jing 2014 Youth Olympic Games can improve its competence by city marketing with the law of Sports Tipping Point. It also put forward the ideas of Tipping Point for Nan Jing Youth Olympic Games.

  16. Robotic therapy: the tipping point.

    Science.gov (United States)

    Krebs, Herman Igo; Hogan, Neville

    2012-11-01

    The last two decades have seen a remarkable shift in the neurorehabilitation paradigm. Neuroscientists and clinicians moved away from the perception that the brain is static and hardwired to a new dynamic understanding that plasticity is a fundamental property of the adult human brain and might be harnessed to remap or create new neural pathways. Capitalizing on this innovative understanding, the authors introduced a paradigm shift in the clinical practice in 1989 when they initiated the development of the Massachusetts Institute of Technology-Manus robot for neurorehabilitation and deployed it in the clinic in 1994 (Krebs et al. 1998). Since then, the authors and others have developed and tested a multitude of robotic devices for stroke, spinal cord injury, cerebral palsy, multiple sclerosis, and Parkinson disease. Here, the authors discuss whether robotic therapy has achieved a level of maturity to justify its broad adoption in the clinical realm as a tool for motor recovery. PMID:23080044

  17. Inner Segment Ellipsoid Band and Cone Outer Segment Tips Changes Preceding Macular Hole Development in a Young Patient

    Directory of Open Access Journals (Sweden)

    Mariana Harasawa

    2014-01-01

    Full Text Available Purpose. Pathophysiology of macular hole (MH is not yet well defined but the advances of spectral domain optical coherence tomography (SD-OCT give us access to further detailed imaging. We report a case with macular inner segment ellipsoid (ISe band loss and cone outer segment tips (COST line changes seen in SD-OCT preceding MH appearance in a young patient. Methods. 21-year-old woman presented with a partial central scotoma, metamorphopsia, and a 20/25 vision in her right eye. Past medical history was positive for laser assisted in situ keratomileusis (LASIK surgery 7 months ago with no complications. Macular SD-OCT showed ISe band loss and COST line elevation. She was followed a month later with visual acuity deteriorating to 20/200 and a full thickness MH. Results. The patient underwent a pars plana vitrectomy with internal limiting membrane peeling. Her visual acuity 2 months later was 20/20. Conclusion. SD-OCT can identify preliminary changes, yet to be described, preceding MH formation. Our patient demonstrated ISe band loss and COST abnormalities on SD-OCT a month prior to MH development. SD-OCT should be considered in young patients with subtle visual symptoms and mild changes in visual acuity that are not readily explained by ophthalmological exam.

  18. CPAP Tips

    Medline Plus

    Full Text Available ... some tips from the U.S. Food and Drug Administration (FDA) on how to safely and effectively use ... more Language: English Country: Worldwide Restricted Mode: Off History Help Loading... Loading... Loading... About Press Copyright Creators ...

  19. Tipping Points towards Regional Forest or Urban Transition in Stressed Rural Areas: An Agent-based Modelling Application of Socio-Economic Shifts in Rural Vermont US

    Science.gov (United States)

    Tsai, Y.; Turnbull, S.; Zia, A.

    2015-12-01

    In rural areas where farming competes with urban development and environmental amenities, urban and forest transitions occur simultaneously at different locales with different rates due to the underlying socio-economic shifts. Here we develop an interactive land use transition agent-based model (ILUTABM) in which farmers' land use decisions are made contingent on expansion and location choices of urban businesses and urban residences, as well as farmers' perceived ecosystem services produced by their land holdings. The ILUTABM simulates heterogeneity in land use decisions at parcel levels by differentiating decision making processes for agricultural and urban landowners. Landowners are simulated to make land-use transition decisions as bounded rational agents that maximize their partial expected utility functions under different underlying socio-economic conditions given the category of a landowner and the spatial characteristics of the landowner's landholdings. The ILUTABM is parameterized by spatial data sets such as National Land Cover Database (NLCD), zoning, parcels, property prices, US census, farmers surveys, building/facility characteristics, soil, slope and elevation. We then apply the ILUTABM to the rural Vermont landscape, located in the Northeast Arm District of Lake Champlain and the downstream sub-watersheds of Missisquoi River, to generate phase transitions of rural land towards urban land near peri-urban areas and towards forest land near financially stressed farmlands during 2001-2051. Possible tipping point trajectories of rural land towards regional forest or urban transition are simulated under three socio-economic scenarios: business as usual (ILUTABM calibrated to 2011 NLCD), increased incentives for conservation easements, and increased incentives for attracting urban residences and businesses.

  20. Change in Intraocular Pressure During Point-of-Care Ultrasound

    Directory of Open Access Journals (Sweden)

    Berg, Cameron

    2015-03-01

    Full Text Available Introduction: Point-of-care ocular ultrasound (US is a valuable tool for the evaluation of traumatic ocular injuries. Conventionally, any maneuver that may increase intraocular pressure (IOP is relatively contraindicated in the setting of globe rupture. Some authors have cautioned against the use of US in these scenarios because of a theoretical concern that an US examination may cause or exacerbate the extrusion of intraocular contents. This study set out to investigate whether ocular US affects IOP. The secondary objective was to validate the intraocular pressure measurements obtained with the Diaton® as compared with standard applanation techniques (the Tono-Pen®.   Methods: We enrolled a convenience sample of healthy adult volunteers. We obtained the baseline IOP for each patient by using a transpalpebral tonometer. Ocular US was then performed on each subject using a high-frequency linear array transducer, and a second IOP was obtained during the US examination. A third IOP measurement was obtained following the completion of the US examination. To validate transpalpebral measurement, a subset of subjects also underwent traditional transcorneal applanation tonometry prior to the US examination as a baseline measurement. In a subset of 10 patients, we obtained baseline pre-ultrasound IOP measurements with the Diaton® and Tono-Pen®, and then compared them.   Results: The study included 40 subjects. IOP values during ocular US examination were slightly greater than baseline (average +1.8mmHg, p=0.01. Post-US examination IOP values were not significantly different than baseline (average -0.15mmHg, p=0.42. In a subset of 10 subjects, IOP values were not significantly different between transpalpebral and transcorneal tonometry (average +0.03mmHg, p=0.07.   Conclusion: In healthy volunteer subjects, point-of-care ocular US causes a small and transient increase in IOP. We also showed no difference between the Diaton® and Tono-Pen® methods

  1. Circulating Elastin Fragments Are Not Affected by Hepatic, Renal and Hemodynamic Changes, But Reflect Survival in Cirrhosis with TIPS

    DEFF Research Database (Denmark)

    Nielsen, M. J.; Lehmann, J; Leeming, D J;

    2015-01-01

    before TIPS with higher levels in the hepatic vein. Interestingly, the circulating ELM levels remained unchanged after TIPS. The circulating levels of ELM in portal and hepatic veins correlated with platelet counts and inversely with serum sodium. Hepatic venous levels of ELM were higher in CHILD C...... compared to CHILD A and B and were associated with the presence of ascites. Patients with high levels of ELM in the hepatic veins before TIPS showed poorer survival. In multivariate analysis ELM levels in the hepatic veins and MELD were independent predictors of mortality in these patients. CONCLUSION...

  2. Default Tips

    OpenAIRE

    Kareem Haggag; Giovanni Paci

    2014-01-01

    We examine the role of defaults in high-frequency, small-scale choices using unique data on over 13 million New York City taxi rides. Using a regression discontinuity design, we show that default tip suggestions have a large impact on tip amounts. These results are supported by a secondary analysis that uses the quasi-random assignment of customers to different cars to examine default effects on a wider range of fares. Finally, we highlight a potential cost of setting defaults too high, as a ...

  3. CPAP Tips

    Medline Plus

    Full Text Available ... some tips from the U.S. Food and Drug Administration (FDA) on how to safely and effectively use ... 743 views 3:51 ABC Good Morning America Health - Sleep Apnea Solutions by 1800CPAP.COM - Duration: 7: ...

  4. Multiple change-points estimation of moving-average processes under dependence assumptions

    Institute of Scientific and Technical Information of China (English)

    ZHANG Lixin; LI Yunxia

    2004-01-01

    In this paper, some results of convergence for a least-square estimator in the problem of multiple change-points estimation are presented and the moving-average processes of ρ-mixing sequence in the mean shifts are discussed. When the number of change points is known, the consistency of change-points estimator is derived. When the number of changes is unknown, the consistency of the change-points number and the change-points estimator by penalized least-squares method are obtained. The results are also true for φ-mixing, α-mixing, associated and negative associated sequences under suitable conditions.

  5. Tip enhancement

    CERN Document Server

    Kawata, Satoshi

    2007-01-01

    This book discusses the recent advances in the area of near-field Raman scattering, mainly focusing on tip-enhanced and surface-enhanced Raman scattering. Some of the key features covered here are the optical structuring and manipulations, single molecule sensitivity, analysis of single-walled carbon nanotubes, and analytic applications in chemistry, biology and material sciences. This book also discusses the plasmonic materials for better enhancement, and optical antennas. Further, near-field microscopy based on second harmonic generation is also discussed. Chapters have been written by some of the leading scientists in this field, who present some of their recent work in this field.·Near-field Raman scattering·Tip-enhanced Raman spectroscopy·Surface-enhanced Raman spectroscopy·Nano-photonics·Nanoanalysis of Physical, chemical and biological materials beyond the diffraction limits·Single molecule detection

  6. Grade Point Average and Changes in (Great) Grade Expectations.

    Science.gov (United States)

    Wendorf, Craig A.

    2002-01-01

    Examines student grade expectations throughout a semester in which students offered their expectations three times during the course: (1) within the first week; (2) midway through the semester; and (3) the week before the final examination. Finds that their expectations decreased stating that their cumulative grade point average was related to the…

  7. Monitoring changes of optical attenuation coefficients of acupuncture points during laser acupuncture by optical coherence tomography

    Science.gov (United States)

    Huang, Yimei; Yang, Hongqin; Wang, Yuhua; Zheng, Liqin; Xie, Shusen

    2010-11-01

    The physical properties of acupuncture point were important to discover the mechanism of acupuncture meridian. In this paper, we used an optical coherence tomography to monitor in vivo the changes of optical attenuation coefficients of Hegu acupuncture point and non-acupuncture point during laser irradiation on Yangxi acupuncture point. The optical attenuation coefficients of Hegu acupuncture point and non-acupuncture point were obtained by fitting the raw data according to the Beer-Lambert's law. The experimental results showed that the optical attenuation coefficient of Hegu acupuncture point decreased during the laser acupuncture, in contrast to a barely changed result in that of non-acupuncture point. The significant change of optical attenuation coefficient of Hegu acupuncture point indicated that there was a correlation between Hegu and Yangxi acupuncture points to some extent.

  8. Two Propositions on the Application of Point Elasticities to Finite Price Changes.

    Science.gov (United States)

    Daskin, Alan J.

    1992-01-01

    Considers counterintuitive propositions about using point elasticities to estimate quantity changes in response to price changes. Suggests that elasticity increases with price along a linear demand curve, but falling quantity demand offsets it. Argues that point elasticity with finite percentage change in price only approximates percentage change…

  9. The development of an information criterion for Change-Point Analysis

    CERN Document Server

    Wiggins, Paul A

    2015-01-01

    Change-point analysis is a flexible and computationally tractable tool for the analysis of times series data from systems that transition between discrete states and whose observables are corrupted by noise. The change-point algorithm is used to identify the time indices (change points) at which the system transitions between these discrete states. We present a unified information-based approach to testing for the existence of change points. This new approach reconciles two previously disparate approaches to Change-Point Analysis (frequentist and information-based) for testing transitions between states. The resulting method is statistically principled, parameter and prior free and widely applicable to a wide range of change-point problems.

  10. A precision of the sequential change point detection

    OpenAIRE

    Ochman-Gozdek, A.; Sarnowski, W; Szajowski, K. J.

    2014-01-01

    A random sequence having two segments being the homogeneous Markov processes is registered. Each segment has his own transition probability law and the length of the segment is unknown and random. The transition probabilities of each process are known and a priori distribution of the disorder moment is given. The decision maker aim is to detect the moment of the transition probabilities change. The detection of the disorder rarely is precise. The decision maker accepts some deviation in estim...

  11. Robust Mean Change-Point Detecting through Laplace Linear Regression Using EM Algorithm

    Directory of Open Access Journals (Sweden)

    Fengkai Yang

    2014-01-01

    normal distribution, we developed the expectation maximization (EM algorithm to estimate the position of mean change-point. We investigated the performance of the algorithm through different simulations, finding that our methods is robust to the distributions of errors and is effective to estimate the position of mean change-point. Finally, we applied our method to the classical Holbert data and detected a change-point.

  12. An objective change-point analysis of historical Atlantic hurricane numbers

    CERN Document Server

    Jewson, S; Jewson, Stephen; Penzer, Jeremy

    2006-01-01

    We perform an objective change-point analysis on 106 years of historical hurricane number data. The algorithm we use looks at all possible combinations of change-points and compares them in terms of the variances of the differences between real and modelled numbers. Overfitting is avoided by using cross-validation. We identify four change-points, and show that the presence of temporal structure in the hurricane number time series is highly statistically significant.

  13. Economics of tipping the climate dominoes

    Science.gov (United States)

    Lemoine, Derek; Traeger, Christian P.

    2016-05-01

    Greenhouse gas emissions can trigger irreversible regime shifts in the climate system, known as tipping points. Multiple tipping points affect each other’s probability of occurrence, potentially causing a `domino effect’. We analyse climate policy in the presence of a potential domino effect. We incorporate three different tipping points occurring at unknown thresholds into an integrated climate-economy model. The optimal emission policy considers all possible thresholds and the resulting interactions between tipping points, economic activity, and policy responses into the indefinite future. We quantify the cost of delaying optimal emission controls in the presence of uncertain tipping points and also the benefit of detecting when individual tipping points have been triggered. We show that the presence of these tipping points nearly doubles today’s optimal carbon tax and reduces peak warming along the optimal path by approximately 1 °C. The presence of these tipping points increases the cost of delaying optimal policy until mid-century by nearly 150%.

  14. Consistency of change point estimators for symmetrical stable distribution with parameters shift

    Institute of Scientific and Technical Information of China (English)

    SHI XiaoPing; MIAO BaiQi; GE ChunLei

    2008-01-01

    Assume that the characteristic index α of stable distribution satisfies 1<α<2, and that the distribution is symmetrical about its mean. We consider the change point estimators for stable distribution with a or scale parameter β shift. For the one case that mean is a known constant, if or β changes, then density function will change too. To this end, we suppose the kernel estimation for a change point. For the other case that mean is an unknown constant, we suppose to apply empirical characteristic function to estimate the change-point location. In the two cases, we consider the consistency and strong convergence rate of estimators. Furthermore, we consider the mean shift case. If mean changes, then corresponding characteristic function will change too. To this end, we also apply empirical characteristic function to estimate change point. We obtain the similar convergence rate. Finally, we consider its application on the detection of mean shift in financial market.

  15. Development and testing of tip devices for horizontal axis wind turbines

    Science.gov (United States)

    Gyatt, G. W.; Lissaman, P. B. S.

    1985-01-01

    A theoretical and field experimental program has been carried out to investigate the use of tip devices on horizontal axis wind turbine rotors. The objective was to improve performance by the reduction of tip losses. While power output can always be increased by a simple radial tip extension, such a modification also results in an increased gale load both because of the extra projected area and longer moment arm. Tip devices have the potential to increase power output without such a structural penalty. A vortex lattice computer model was used to optimize three basic tip configuration types for a 25 kW stall limited commercial wind turbine. The types were a change in tip planform, and a single-element and double-element nonplanar tip extension (winglets). A complete data acquisition system was developed which recorded three wind speed components, ambient pressure, temperature, and turbine output. The system operated unattended and could perform real-time processing of the data, displaying the measured power curve as data accumulated in either a bin sort mode or polynomial curve fit. Approximately 270 hr of perormance data were collected over a three-month period. The sampling interval was 2.4 sec; thrus over 400,000 raw data points were logged. Results for each of the three new tip devices, compared with the original tip, showed a small decrease (of the order of 1 kW) in power output over the measured range of wind speeds from cut-in at about 4 m/s to over 20 m/s, well into the stall limiting region. Changes in orientation and angle-of-attack of the winglets were not made. For aircraft wing tip devices, favorable tip shapes have been reported and it is likely that the tip devices tested in this program did not improve rotor performance because they were not optimally adjusted.

  16. Abrupt change point detection of annual maximum precipitation using fused lasso

    Science.gov (United States)

    Jeon, Jong-June; Sung, Jang Hyun; Chung, Eun-Sung

    2016-07-01

    Because the widely used Bayesian change point analysis (BCPA) is generally applied to the normal distribution, it cannot be freely used to the annual maximum precipitations (AMP) in South Korea. Therefore, this study proposed the fused lasso penalty function to detect the change point of AMP which can be generally fitted by using the Generalized Extreme Value (GEV) distribution in South Korea. First, four numerical experiments are conducted to compare the detection performances between BCPA and fused lasso method. As a result, fused lasso shows the superiority of the data generated by GEV distribution having skewness. The fused lasso method is applied to 63 weather stations in South Korea and then 17 stations having any change points from BCPA and the GEV fused lasso are analyzed. Similar to the numerical analyses, the GEV fused lasso method can delicately detect the change point of AMPs. After the change point, the means of AMPs did not go back to the previous. Alternately, BCPA can be stated to find variation points not change points because the means returned to their original values as time progressed. Therefore, it can be concluded that the GEV fused lasso method detects the change points of non-stationary AMPs of South Korea. This study can be extended to more extreme distributions for various meteorological variables.

  17. BetterPoints: Motivating behaviour change using technology-driven incentivisation

    Directory of Open Access Journals (Sweden)

    Anne Lancaster

    2015-10-01

    The BetterPoints system is unique in it’s flexibility and ability to draw on multiple behaviour change models to create high quality interventions. Early findings from existing programmes being implemented for Local Authorities in the UK suggest that BetterPoints can demonstrate real-world behaviour change. We would like to work with academic partners to further investigate these real-world changes in behaviour and establish a robust evidence base.

  18. Detection of Change--Points in the Spectral Density. With Applications to ECG Data

    OpenAIRE

    Bertrand, Pierre; Teyssière, Gilles; Boudet, Gil; Chamoux, Alain

    2008-01-01

    proceeding of the workshop 'Fouille de données temporelles et analyse de flux de données' EGC'2009, january 27, Strasbourg, France We propose a new method for estimating the change-points of heart rate in the orthosympathetic and parasympathetic bands, based on the wavelet transform in the complex domain and the study of the change-points in the moments of the modulus of these wavelet transforms. We observe change-points in the distribution for both bands.

  19. Change-point detection in the historical hurricane number time-series: why can't we detect change-points at US landfall?

    CERN Document Server

    Nzerem, K; Laepple, T; Nzerem, Kechi; Jewson, Stephen; Laepple, Thomas

    2006-01-01

    The time series of the number of hurricanes per year in the Atlantic basin shows a clear change of level between 1994 and 1995. The time series of the number of hurricanes that make landfall in the US, however, does not show the same obvious change of level. Prima-facie this seems rather surprising, given that the landfalling hurricanes are a subset of the basin hurricanes. We investigate whether it really should be considered surprising or whether there is a simple statistical explanation for the disappearance of this change-point at landfall.

  20. Deciphering behavioral changes in animal movement with a ‘multiple change point algorithm- classification tree’ framework

    Directory of Open Access Journals (Sweden)

    Benedicte eMadon

    2014-07-01

    Full Text Available The recent development of tracking tools has improved our nascent knowledge on animal movement. Because of model complexity, unrealistic a priori hypotheses and heavy computational resources, behavioral changes along an animal path are still often assessed visually. A new avenue has recently been opened with change point algorithms because tracking data can be organized as time series with potential periodic change points segregating the movement in segments of different statistical properties. So far this approach was restricted to single change point detection and we propose a straightforward analytical framework based on a recent multiple change point algorithm: the PELT algorithm, a dynamic programming pruning search method to find, within time series, the optimal combination of number and locations of change points. Data segments found by the algorithm are then sorted out with a supervised classification tree procedure to organize segments by movement classes. We apply this framework to investigate changes in variance in daily distances of a migratory bird, the Macqueen’s Bustard, Chlamydotis macqueenii, and describe its movements in three classes: staging, non-migratory and migratory movements. Using simulation experiments, we show that the algorithm is robust to identify exact behavioral shift (on average more than 80% of the time but that positive autocorrelation when present is likely to lead to the detection of false change points (in 36% of the iterations with an average of 1.97 (se = 0.06 additional change points. A case study is provided to illustrate the biases associated with visual analysis of movement patterns compared to the reliability of our analytical framework. Technological improvement will provide new opportunities for the study of animal behavior, bringing along huge and various data sets, a growing challenge for biologists, and this straightforward and standardized framework could be an asset in the attempt to

  1. Effect of incisor inclination changes on cephalometric points a and b

    International Nuclear Information System (INIS)

    The position of cephalometric points A and B are liable to be affected by alveolar remodelling caused by orthodontic tooth movement during incisor retraction. This study was conducted to evaluate the change in positions of cephalometric points A and B in sagittal and vertical dimensions due to change in incisor inclinations. Methods: Total sample of 31 subjects were recruited into the study. The inclusion criteria were extraction of premolars in upper and lower arches, completion of growth and orthodontic treatment. The exclusion criteria were patients with craniofacial anomalies and history of orthodontic treatment. By superimposition of pre and post treatment tracings, various linear and angular parameters were measured. Various tests and multiple linear regression analysis were performed to determine changes in outcome variables. Statistically significant p-value was <0.05. Results:One-sample t-test showed that change in position of only point A was statistically significant which was 1.61mm (p<0.01) in sagittal direction and 1.49mm (p<0.01) in vertical direction. Multiple linear regression analysis showed that if we retrocline upper incisor by 100, the point A will move superiorly by 0.6mm. Conclusions: Total change in the position of point A is in a downward and forward direction. Total Change in upper incisors inclinations causes change in position of point A only in vertical direction. (author)

  2. Probe tip heating assembly

    Energy Technology Data Exchange (ETDEWEB)

    Schmitz, Roger William; Oh, Yunje

    2016-10-25

    A heating assembly configured for use in mechanical testing at a scale of microns or less. The heating assembly includes a probe tip assembly configured for coupling with a transducer of the mechanical testing system. The probe tip assembly includes a probe tip heater system having a heating element, a probe tip coupled with the probe tip heater system, and a heater socket assembly. The heater socket assembly, in one example, includes a yoke and a heater interface that form a socket within the heater socket assembly. The probe tip heater system, coupled with the probe tip, is slidably received and clamped within the socket.

  3. An objective change point analysis of landfalling historical Atlantic hurricane numbers

    CERN Document Server

    Jewson, S; Jewson, Stephen; Penzer, Jeremy

    2006-01-01

    In previous work we have analysed the Atlantic basin hurricane number time-series to identify decadal time-scale change points. We now repeat the analysis but for US landfalling hurricanes. The results are very different.

  4. Optimization of STM-tip preparation methods

    OpenAIRE

    Revenikiotis, Sackis (Athanasios)

    2011-01-01

    The Scanning Tunneling Microscope (STM) was invented by Gerd Binnig and Heinrich Rohrer and gave them the Nobel Prize in Physics 1986. STM can give us atomic resolution of a surface by applying a voltage between a very sharp tip (STM-tip) and the surface of a material that we want to examine. The STM-tip is moving over the surface and a computer is collecting the tunnel current in every single point to create a digital image. This diploma work is focused on the preparation of the STM-tip. The...

  5. Office 2010 Visual Quick Tips

    CERN Document Server

    Gunter, Sherry Kinkoph

    2010-01-01

    Get more done in Office 2010 in less time with these Quick Tips!. Whether you're new to Microsoft Office or updating from older versions, this is the perfect resource to get you quickly up to speed on Office 2010. Every application is covered, including Word, Excel, PowerPoint, Outlook, and Publisher. Full-color screenshots and numbered steps clearly explain dozens of features and functions-while quick shortcuts, tips, and tricks help you save time and boost productivity. You'll also find great new ways to access and use some Office apps right from the Web.: Walks you through dozens of new fea

  6. CHANG'E-5T1 extended mission: The first lunar libration point flight via a lunar swing-by

    Science.gov (United States)

    Liu, Lei; Li, Ji-sheng

    2016-08-01

    This paper introduces the extended mission of the Chinese circumlunar return and reentry test (i.e., the CHANG'E-5T1 mission), the first Chinese flight in the Earth-Moon libration orbit and the first spacecraft to reach the Earth-Moon libration orbit via a lunar swing-by. The extended mission utilized the remaining propellant from the CHANG'E-5T1 mission. Based on the normal trajectory and satellite state at the end of the CHANG'E-5T1 mission, a lunar return and a flight in the lunar libration orbit were determined to be the flight goals of the extended mission. Two schemes were then proposed for the CHANG'E-5T1 extended mission, including a possible Earth-Moon libration orbit. The methodology for the trajectory design and maneuvering included the direct libration-point orbit transfer and injection method, which is characterized by a reduced calculation burden compared with the prevalent invariant manifold method. The scenarios were compared in terms of flight time, control energy and number of maneuvers, flight distance, and achieved flight goals. The comparison indicated that the scheme, including the Earth-Moon L2 point and return to the Moon, was preferred for the CHANG'E-5T1 extended mission. Furthermore, the actual flight parameters of the CHANG'E-5T1 extended mission are also presented to validate the selected scheme.

  7. Consistency of change point estimators for symmetrical stable distribution with parameters shift

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Assume that the characteristic indexαof stable distribution satisfies 1<α<2,and that the distribution is symmetrical about its mean.We consider the change point estimators for stable distribution withαor scale parameterβshift.For the one case that mean is a known constant,ifαorβchanges,then density function will change too.To this end,we suppose the kernel estimation for a change point.For the other case that mean is an unknown constant,we suppose to apply empirical characteristic function to estimate the change-point location.In the two cases,we consider the consistency and strong convergence rate of estimators.Furthermore,we consider the mean shift case.If mean changes,then corresponding characteristic function will change too.To this end,we also apply empirical characteristic function to estimate change point.We obtain the similar convergence rate.Finally,we consider its application on the detection of mean shift in financial market.

  8. Optimal Parameter Exploration for Online Change-Point Detection in Activity Monitoring Using Genetic Algorithms

    Directory of Open Access Journals (Sweden)

    Naveed Khan

    2016-10-01

    Full Text Available In recent years, smart phones with inbuilt sensors have become popular devices to facilitate activity recognition. The sensors capture a large amount of data, containing meaningful events, in a short period of time. The change points in this data are used to specify transitions to distinct events and can be used in various scenarios such as identifying change in a patient’s vital signs in the medical domain or requesting activity labels for generating real-world labeled activity datasets. Our work focuses on change-point detection to identify a transition from one activity to another. Within this paper, we extend our previous work on multivariate exponentially weighted moving average (MEWMA algorithm by using a genetic algorithm (GA to identify the optimal set of parameters for online change-point detection. The proposed technique finds the maximum accuracy and F_measure by optimizing the different parameters of the MEWMA, which subsequently identifies the exact location of the change point from an existing activity to a new one. Optimal parameter selection facilitates an algorithm to detect accurate change points and minimize false alarms. Results have been evaluated based on two real datasets of accelerometer data collected from a set of different activities from two users, with a high degree of accuracy from 99.4% to 99.8% and F_measure of up to 66.7%.

  9. Change-Point Detection in Time-Series Data by Relative Density-Ratio Estimation

    CERN Document Server

    Liu, Song; Collier, Nigel; Sugiyama, Masashi

    2012-01-01

    The objective of change-point detection is to discover abrupt property changes lying behind time series data. In this paper, we present a novel statistical change-point detection algorithm that is based on non-parametric divergence estimation between two retrospective segments. Our method uses the relative Pearson divergence as a divergence measure, and it is accurately and efficiently estimated by a method of direct density-ratio estimation. Through experiments on artificial and real-world datasets including human-activity sensing, speeches, and Twitter archives, we demonstrate the usefulness of the proposed method.

  10. BetterPoints: Motivating behaviour change using technology-driven incentivisation

    OpenAIRE

    Anne Lancaster

    2015-01-01

    Background Conference theme: Using behaviour change theory to create high-quality interventions and products. BetterPoints is a localised behaviour change system that uses incentivisation, recognition and social interaction – all driven by an innovative technology. Our main method of engagement is a proprietary smartphone app. The app is part of a powerful behaviour change technology platform that allows rapid customisation, massive reward flexibility and sophisticated reporting. This...

  11. On changing points of mean residual life and failure rate function for some generalized Weibull distributions

    International Nuclear Information System (INIS)

    The failure rate function and mean residual life function are two important characteristics in reliability analysis. Although many papers have studied distributions with bathtub-shaped failure rate and their properties, few have focused on the underlying associations between the mean residual life and failure rate function of these distributions, especially with respect to their changing points. It is known that the change point for mean residual life can be much earlier than that of failure rate function. In fact, the failure rate function should be flat for a long period of time for a distribution to be useful in practice. When the difference between the change points is large, the flat portion tends to be longer. This paper investigates the change points and focuses on the difference of the changing points. The exponentiated Weibull, a modified Weibull, and an extended Weibull distribution, all with bathtub-shaped failure rate function will be used. Some other issues related to the flatness of the bathtub curve are discussed

  12. Diet and Exercise Tips

    Science.gov (United States)

    ... Health News & Publications Annual Meeting Calendar Diet and Exercise Tips Diet and Exercise Tips News media interested ... caffeine content (tea, sodas, chocolate drinks) and caffeinated coffee to two cups per day. Minimize alcohol to ...

  13. Optical fiber tip with point light source of SPPs driven by three-dimensional nanostructured asymmetric metal-insulator-metal layer cap

    Science.gov (United States)

    Oshikane, Yasushi; Murai, Kensuke; Nakano, Motohiro

    2015-09-01

    Numerical analysis of three dimensional optical electro-magnetic field in a circular-truncated conical optical fiber covered by asymmetric MIM structure has been performed by a commercial finite element method package, COMSOL Multiphysics coupled with Wave Optics Module. The outermost thick metallic layer has twin nano-hole, and the waveguiding twin-hole could draw surface plasmon polaritions (SPPs) excited in the MIM structure to the surface. Finally the guided two SPPs could unite each other and may create a single bright spot. The systematic simulation is continuing, and the results will give us valuable counsel for control of surface plasmon polaritons (SPPs) appearing around the MIM structure and twin nano-hole. (1) Optimal design of the 3D FEM model for 8-core Xeon server and rational approach for the FEM analysis, (2) behavior of SPPs affected by wavelength and polarization of light travel through fiber, (3) change in excitation condition of SPPs caused by shape of the MIM structure and twin-hole, (4) effectiveness of additional nanostructures that are aimed at focusing control of two SPPs come out from the corners of twin-hole, (5) scanning ability of the MIM/twin-hole probe at nanostructured sample surface (i.e. amount of forward and backward scattering of SPPs) will be presented and discussed. Several FIBed prototypes and their characteristic of light emission will also reported.

  14. 3D change detection at street level using mobile laser scanning point clouds and terrestrial images

    Science.gov (United States)

    Qin, Rongjun; Gruen, Armin

    2014-04-01

    Automatic change detection and geo-database updating in the urban environment are difficult tasks. There has been much research on detecting changes with satellite and aerial images, but studies have rarely been performed at the street level, which is complex in its 3D geometry. Contemporary geo-databases include 3D street-level objects, which demand frequent data updating. Terrestrial images provides rich texture information for change detection, but the change detection with terrestrial images from different epochs sometimes faces problems with illumination changes, perspective distortions and unreliable 3D geometry caused by the lack of performance of automatic image matchers, while mobile laser scanning (MLS) data acquired from different epochs provides accurate 3D geometry for change detection, but is very expensive for periodical acquisition. This paper proposes a new method for change detection at street level by using combination of MLS point clouds and terrestrial images: the accurate but expensive MLS data acquired from an early epoch serves as the reference, and terrestrial images or photogrammetric images captured from an image-based mobile mapping system (MMS) at a later epoch are used to detect the geometrical changes between different epochs. The method will automatically mark the possible changes in each view, which provides a cost-efficient method for frequent data updating. The methodology is divided into several steps. In the first step, the point clouds are recorded by the MLS system and processed, with data cleaned and classified by semi-automatic means. In the second step, terrestrial images or mobile mapping images at a later epoch are taken and registered to the point cloud, and then point clouds are projected on each image by a weighted window based z-buffering method for view dependent 2D triangulation. In the next step, stereo pairs of the terrestrial images are rectified and re-projected between each other to check the geometrical

  15. Detecting functional connectivity change points for single-subject fMRI data.

    Science.gov (United States)

    Cribben, Ivor; Wager, Tor D; Lindquist, Martin A

    2013-01-01

    Recently in functional magnetic resonance imaging (fMRI) studies there has been an increased interest in understanding the dynamic manner in which brain regions communicate with one another, as subjects perform a set of experimental tasks or as their psychological state changes. Dynamic Connectivity Regression (DCR) is a data-driven technique used for detecting temporal change points in functional connectivity between brain regions where the number and location of the change points are unknown a priori. After finding the change points, DCR estimates a graph or set of relationships between the brain regions for data that falls between pairs of change points. In previous work, the method was predominantly validated using multi-subject data. In this paper, we concentrate on single-subject data and introduce a new DCR algorithm. The new algorithm increases accuracy for individual subject data with a small number of observations and reduces the number of false positives in the estimated undirected graphs. We also introduce a new Likelihood Ratio test for comparing sparse graphs across (or within) subjects; thus allowing us to determine whether data should be combined across subjects. We perform an extensive simulation analysis on vector autoregression (VAR) data as well as to an fMRI data set from a study (n = 23) of a state anxiety induction using a socially evaluative threat challenge. The focus on single-subject data allows us to study the variation between individuals and may provide us with a deeper knowledge of the workings of the brain.

  16. Change of elastic constants induced by point defects in hop crystals

    International Nuclear Information System (INIS)

    An approximate model is developed to calculate the change of elastic constants induced by point defects in hcp metals, supposed the defect configuration is known. General expressions relating the change of elastic moduli to the final atomic coordinates and to the defect force field are derived using the specific symmetry of the defect. Explicit calculations are done for Mg. The predicted change of elastic moduli turns out to be negative for vacancies and trigonal interstitials while for hexagonal interstitials a positive change is predicted. Compatibility with experimental data would suggest that the trigonal configuration is the stable one. (author)

  17. Change of performance of a horizontal wind turbine with V type tip vane%风力机加V型小翼后的性能变化

    Institute of Scientific and Technical Information of China (English)

    贾瑞博; 汪建文

    2011-01-01

    试验和数值模拟证明,在风力机叶片的叶尖添加小翼,可以提高风能转化效率.为了清楚地了解小翼对风力机动力放大的影响,文章基于叶轮周围流场的数值模拟结果,分析了加V型小翼和不加小翼的风力机流场-速度场和压力场特性.可以看出,小翼对风力机叶片叶端的影响较大,风力机叶尖的漩涡强度降低,能量转换效率提高.%It was proved that a tip vane could improve thewind turbine's efficiency by the test and the numerical simulation. In order to distinctly understand the power augmentation effect of the wind turbine by the tip vane, this paper analyzed the flow field of the wind turbine with the V type tip vane and without a tip vane, as well as the characteristics of the velocity field and the pressure field, which based on the numerical simulation result of the flow field of the wind turbine. The tip vane has more influence to the blade tip of the wind turbine. The vortex intensity around the blade tip was reduced and the energy transformation efficiency was improved.

  18. Evaluating Change in Behavioral Preferences: Multidimensional Scaling Single-Ideal Point Model

    Science.gov (United States)

    Ding, Cody

    2016-01-01

    The purpose of the article is to propose a multidimensional scaling single-ideal point model as a method to evaluate changes in individuals' preferences under the explicit methodological framework of behavioral preference assessment. One example is used to illustrate the approach for a clear idea of what this approach can accomplish.

  19. Single and Multiple Change Point Detection in Spike Trains: Comparison of Different CUSUM Methods

    Science.gov (United States)

    Koepcke, Lena; Ashida, Go; Kretzberg, Jutta

    2016-01-01

    In a natural environment, sensory systems are faced with ever-changing stimuli that can occur, disappear or change their properties at any time. For the animal to react adequately the sensory systems must be able to detect changes in external stimuli based on its neuronal responses. Since the nervous system has no prior knowledge of the stimulus timing, changes in stimulus need to be inferred from the changes in neuronal activity, in particular increase or decrease of the spike rate, its variability, and shifted response latencies. From a mathematical point of view, this problem can be rephrased as detecting changes of statistical properties in a time series. In neuroscience, the CUSUM (cumulative sum) method has been applied to recorded neuronal responses for detecting a single stimulus change. Here, we investigate the applicability of the CUSUM approach for detecting single as well as multiple stimulus changes that induce increases or decreases in neuronal activity. Like the nervous system, our algorithm relies exclusively on previous neuronal population activities, without using knowledge about the timing or number of external stimulus changes. We apply our change point detection methods to experimental data obtained by multi-electrode recordings from turtle retinal ganglion cells, which react to changes in light stimulation with a range of typical neuronal activity patterns. We systematically examine how variations of mathematical assumptions (Poisson, Gaussian, and Gamma distributions) used for the algorithms may affect the detection of an unknown number of stimulus changes in our data and compare these CUSUM methods with the standard Rate Change method. Our results suggest which versions of the CUSUM algorithm could be useful for different types of specific data sets. PMID:27445714

  20. Mobile Learning: At the Tipping Point

    Science.gov (United States)

    Franklin, Teresa

    2011-01-01

    Mobile technologies are interfacing with all aspects of our lives including Web 2.0 tools and applications, immersive virtual world environments, and online environments to present educational opportunities for 24/7 learning at the learner's discretion. Mobile devices are allowing educators to build new community learning ecosystems for and by…

  1. European Fisheries at a Tipping-Point

    DEFF Research Database (Denmark)

    Schriewer, Klaus

    Analyse og syntese af de biologiske livsformers betydning som mulighedsbetingelse for de anvendte teknologier og fangstmåders betydning som mulighedsbetingelse for de to produktionsmåders sameksistens i euroæisk fiskeri i 500 år og deres betydning som mulighedsbetingelser for de sameksisterende k...

  2. Nearly Optimal Change-Point Detection with an Application to Cybersecurity

    CERN Document Server

    Polunchenko, Aleksey S; Mukhopadhyay, Nitis

    2012-01-01

    We address the sequential change-point detection problem for the Gaussian model where baseline distribution is Gaussian with variance \\sigma^2 and mean \\mu such that \\sigma^2=a\\mu, where a>0 is a known constant; the change is in \\mu from one known value to another. First, we carry out a comparative performance analysis of four detection procedures: the CUSUM procedure, the Shiryaev-Roberts (SR) procedure, and two its modifications - the Shiryaev-Roberts-Pollak and Shiryaev-Roberts-r procedures. The performance is benchmarked via Pollak's maximal average delay to detection and Shiryaev's stationary average delay to detection, each subject to a fixed average run length to false alarm. The analysis shows that in practically interesting cases the accuracy of asymptotic approximations is "reasonable" to "excellent". We also consider an application of change-point detection to cybersecurity - for rapid anomaly detection in computer networks. Using real network data we show that statistically traffic's intensity can...

  3. Modeling Menstrual Cycle Length and Variability at the Approach of Menopause Using Hierarchical Change Point Models.

    Science.gov (United States)

    Huang, Xiaobi; Elliott, Michael R; Harlow, Siobán D

    2014-04-01

    As women approach menopause, the patterns of their menstrual cycle lengths change. To study these changes, we need to jointly model both the mean and variability of cycle length. Our proposed model incorporates separate mean and variance change points for each woman and a hierarchical model to link them together, along with regression components to include predictors of menopausal onset such as age at menarche and parity. Additional complexity arises from the fact that the calendar data have substantial missingness due to hormone use, surgery, and failure to report. We integrate multiple imputation and time-to event modeling in a Bayesian estimation framework to deal with different forms of the missingness. Posterior predictive model checks are applied to evaluate the model fit. Our method successfully models patterns of women's menstrual cycle trajectories throughout their late reproductive life and identifies change points for mean and variability of segment length, providing insight into the menopausal process. More generally, our model points the way toward increasing use of joint mean-variance models to predict health outcomes and better understand disease processes.

  4. Homogeneity and change-point detection tests for multivariate data using rank statistics

    CERN Document Server

    Lung-Yut-Fong, Alexandre; Cappé, Olivier

    2011-01-01

    Detecting and locating changes in highly multivariate data is a major concern in several current statistical applications. In this context, the first contribution of the paper is a novel non-parametric two-sample homogeneity test for multivariate data based on the well-known Wilcoxon rank statistic. The proposed two-sample homogeneity test statistic can be extended to deal with ordinal or censored data as well as to test for the homogeneity of more than two samples. The second contribution of the paper concerns the use of the proposed test statistic to perform retrospective change-point analysis. It is first shown that the approach is computationally feasible even when looking for a large number of change-points thanks to the use of dynamic programming. Computable asymptotic $p$-values for the test are then provided in the case where a single potential change-point is to be detected. Compared to available alternatives, the proposed approach appears to be very reliable and robust. This is particularly true in ...

  5. Detecting functional connectivity change points for single-subject fMRI data

    Directory of Open Access Journals (Sweden)

    Ivor eCribben

    2013-10-01

    Full Text Available Recently in functional magnetic resonance imaging (fMRI studies there has been an increased interest in understanding the dynamic manner in which brain regions communicate with one another, as subjects perform a set of experimental tasks or as their psychological state changes. Dynamic Connectivity Regression (DCR is a data-driven technique used for detecting temporal change points in functional connectivity between brain regions where the number and location of the change points are unknown a priori. After finding the change points, DCR estimates a graph or set of relationships between the brain regions for data that falls between pairs of change points. In previous work, the method was predominantly validated using multi-subject data. In this paper, we concentrate on single-subject data and introduce a new DCR algorithm. The new algorithm increases accuracy for individual subject data with a small number of observations and reduces the number of false positives in the estimated undirected graphs. We also introduce a new Likelihood Ratio test for comparing sparse graphs across (or within subjects; thus allowing us to determine whether data should be combined across subjects. We perform an extensive simulation analysis on vector autoregression (VAR data as well as to an fMRI data set from a study (n=23 of a state anxiety induction using a socially evaluative threat challenge. The focus on single-subject data allows us to study the variation between individuals and may provide us with a deeper knowledge of the workings of the brain.

  6. CFD-based simulation of operational point influences on product changing processes

    Science.gov (United States)

    Szöke, L.; Wortberg, J.

    2014-05-01

    In the means of production, saving resources is becoming more and more a priority optimizing plastics extrusion processes. The analysis of color and material changes has become very interesting to prevent unnecessary material loss. This interest is justified especially due to increasing numbers of changing processes as a reaction of more individual product specifications and thus decreasing lot sizes in the last decades. It can be shown that commercial numerical tools are capable of plausible calculations of changing processes, enabling process observations and giving the possibility of predicting different influences. Due to the highly dynamical character of the flow behavior in the control volume, a transient approach is necessary to show the effects of different operational points on product changes. To determine the progress of the product change the volume of fluid model (VOF) as multiphase approach is used. The analysis of influences from operational points on the changing process is achieved by separate observations of two important input parameters. On one hand the effects of varied mass flow rates as inlet boundary conditions and on the other hand different mass temperatures are observed. To check the plausibility of the calculation method the results are discussed referring to exemplary experimental data in qualitative comparison. The experimental data is obtained using special laboratory equipment neglecting influences from the extruder and taking only the die as control volume into consideration.

  7. Changes in freezing point of blood and milk during dehydration and rehydration in lactating cows

    DEFF Research Database (Denmark)

    Bjerg, M.; Rasmussen, M.D.; Nielsen, Mette Olaf

    2005-01-01

    We studied the influence of short-term changes in water intake in 4 lactating Holstein cows on diurnal fluctuation of packed cell volume (PCV), freezing point of blood (FP blood), freezing point of milk ( FP milk), and the relationship between changes in FP blood and FP milk. The experiment lasted...... the jugular vein hourly throughout the experiment, and at 0, 15, 30, 60, 90, 120, 150, 180, 210, and 240 min after initiated rehydration following the 8-h dehydration sequences. Intakes of free water and water in feed were recorded every hour. The PCV was negatively affected by water intake within the hour...... before sampling. Dehydration lowered FP blood steadily, whereas FP blood increased by 0.024°C within 30 min following a large water intake in the rehydration period. The FP blood was not significantly influenced by actual water intake, but was highly correlated with the available water pool at time...

  8. Comparisons of changes in the two-point discrimination test following muscle fatigue in healthy adults

    OpenAIRE

    Han, Jintae; Park, Soojin; Jung, Seonghyun; Choi, Yeounsung; Song, Hyunjoo

    2015-01-01

    [Purpose] This study aimed to examine the effects of muscle fatigue on skin sensation by looking at changes in two-point discrimination (2PD) after inducing muscle fatigue. [Subjects] Thirty-four young and healthy adults with no pathological symptoms (17 males; 17 females) participated in this study. [Methods] Continuous isometric contraction was applied to the upper and lower extremities with an intensity of 50% of the maximal muscle strength to trigger muscle fatigue, and then the 2PD test ...

  9. Non-parametric change-point method for differential gene expression detection.

    Directory of Open Access Journals (Sweden)

    Yao Wang

    Full Text Available BACKGROUND: We proposed a non-parametric method, named Non-Parametric Change Point Statistic (NPCPS for short, by using a single equation for detecting differential gene expression (DGE in microarray data. NPCPS is based on the change point theory to provide effective DGE detecting ability. METHODOLOGY: NPCPS used the data distribution of the normal samples as input, and detects DGE in the cancer samples by locating the change point of gene expression profile. An estimate of the change point position generated by NPCPS enables the identification of the samples containing DGE. Monte Carlo simulation and ROC study were applied to examine the detecting accuracy of NPCPS, and the experiment on real microarray data of breast cancer was carried out to compare NPCPS with other methods. CONCLUSIONS: Simulation study indicated that NPCPS was more effective for detecting DGE in cancer subset compared with five parametric methods and one non-parametric method. When there were more than 8 cancer samples containing DGE, the type I error of NPCPS was below 0.01. Experiment results showed both good accuracy and reliability of NPCPS. Out of the 30 top genes ranked by using NPCPS, 16 genes were reported as relevant to cancer. Correlations between the detecting result of NPCPS and the compared methods were less than 0.05, while between the other methods the values were from 0.20 to 0.84. This indicates that NPCPS is working on different features and thus provides DGE identification from a distinct perspective comparing with the other mean or median based methods.

  10. Change points in the series of T4 counts prior to AIDS.

    Science.gov (United States)

    Kiuchi, A S; Hartigan, J A; Holford, T R; Rubinstein, P; Stevens, C E

    1995-03-01

    The absolute number of T4 cells has been established as an important clinical marker of disease progression to acquired immunodeficiency syndrome (AIDS) in persons infected with human immunodeficiency virus (HIV). Series of T4 counts are analyzed from the 131 homosexual men who entered the New York Blood Center Study in 1984, mostly seropositive for HIV, and who developed AIDS as participants by 1990. These series exhibit a gradual decline of the log(T4) count followed by a more rapid decline close to the time of the development of AIDS. Empirical Bayes and hierarchical Bayes change point models are proposed to estimate the distribution of the time before AIDS when this rapid decline begins. Results using the EM Algorithm and Markov chain Monte Carlo indicate that the mean change point occurs approximately 1 year before diagnosis with a standard deviation of 9 months. Detection of a change point may indicate that an AIDS diagnosis is increasingly likely for an individual HIV-positive but AIDS-free. PMID:7766779

  11. Fast and Robust Segmentation and Classification for Change Detection in Urban Point Clouds

    Science.gov (United States)

    Roynard, X.; Deschaud, J.-E.; Goulette, F.

    2016-06-01

    Change detection is an important issue in city monitoring to analyse street furniture, road works, car parking, etc. For example, parking surveys are needed but are currently a laborious task involving sending operators in the streets to identify the changes in car locations. In this paper, we propose a method that performs a fast and robust segmentation and classification of urban point clouds, that can be used for change detection. We apply this method to detect the cars, as a particular object class, in order to perform parking surveys automatically. A recently proposed method already addresses the need for fast segmentation and classification of urban point clouds, using elevation images. The interest to work on images is that processing is much faster, proven and robust. However there may be a loss of information in complex 3D cases: for example when objects are one above the other, typically a car under a tree or a pedestrian under a balcony. In this paper we propose a method that retain the three-dimensional information while preserving fast computation times and improving segmentation and classification accuracy. It is based on fast region-growing using an octree, for the segmentation, and specific descriptors with Random-Forest for the classification. Experiments have been performed on large urban point clouds acquired by Mobile Laser Scanning. They show that the method is as fast as the state of the art, and that it gives more robust results in the complex 3D cases.

  12. Tip Studies using CFD and Comparison with Tip Loss Models

    DEFF Research Database (Denmark)

    Hansen, Martin Otto Laver

    2004-01-01

    The flow past a 95 kW Tellus rotor equipped with LM8.2 blades is computed using computational fluid dynamics for a standard tip and a swept tip. The difference in the near-tip flow for the two tips for various tip speed ratios is examined and 3D airfoil data are extracted. The radial distribution...

  13. Optical imaging beyond the diffraction limit by SNEM: Effects of AFM tip modifications with thiol monolayers on imaging quality

    Energy Technology Data Exchange (ETDEWEB)

    Cumurcu, Aysegul [Materials Science and Technology of Polymers, MESA+ Institute for Nanotechnology, University of Twente, Enschede NL-7500 (Netherlands); Dutch Polymer Institute (DPI), P.O. Box 902, 5600 AX, Eindhoven (Netherlands); Diaz, Jordi [Scientific and Technological Centers of the University of Barcelona, C/ Lluís Solé i Sabaris, 1-3, 08028 Barcelona (Spain); Lindsay, Ian D. [Nanophysics and Soft Matter Group, H.H. Wills Physics Laboratory, University of Bristol, Tyndall Avenue, Bristol BS8 1TL (United Kingdom); Beer, Sissi de; Duvigneau, Joost [Materials Science and Technology of Polymers, MESA+ Institute for Nanotechnology, University of Twente, Enschede NL-7500 (Netherlands); Schön, Peter [Materials Science and Technology of Polymers, MESA+ Institute for Nanotechnology, University of Twente, Enschede NL-7500 (Netherlands); NanoBioInterface, Research Center Design and Technology, Saxion University of Applied Sciences, 7500 KB Enschede (Netherlands); Julius Vancso, G., E-mail: g.j.vancso@utwente.nl [Materials Science and Technology of Polymers, MESA+ Institute for Nanotechnology, University of Twente, Enschede NL-7500 (Netherlands)

    2015-03-15

    Tip-enhanced nanoscale optical imaging techniques such as apertureless scanning near-field optical microscopy (a-SNOM) and scanning near-field ellipsometric microscopy (SNEM) applications can suffer from a steady degradation in performance due to adhesion of atmospheric contaminants to the metal coated tip. Here, we demonstrate that a self-assembled monolayer (SAM) of ethanethiol (EtSH) is an effective means of protecting gold-coated atomic force microscopy (AFM) probe tips from accumulation of surface contaminants during prolonged exposure to ambient air. The period over which they yield consistent and reproducible results for scanning near-field ellipsometric microscopy (SNEM) imaging is thus extended. SNEM optical images of a microphase separated polystyrene-block-poly (methylmethacrylate) (PS-b-PMMA) diblock copolymer film, which were captured with bare and SAM-protected gold-coated AFM probes, both immediately after coating and following five days of storage in ambient air, were compared. During this period the intensity of the optical signals from the untreated gold tip fell by 66%, while those from the SAM protected tip fell by 14%. Additionally, gold coated AFM probe tips were modified with various lengths of alkanethiols to measure the change in intensity variation in the optical images with SAM layer thickness. The experimental results were compared to point dipole model calculations. While a SAM of 1-dodecanethiol (DoSH) was found to strongly suppress field enhancement we find that it can be locally removed from the tip apex by deforming the molecules under load, restoring SNEM image contrast. - Highlights: • SAM of ethanethiol is used to prevent contamination of gold coated tips. • Functionalizing gold coated tips with a SAM lead to reproducible SNEM imaging. • Point dipole model agreed with the experimental results of the SNEM images. • SAM of 1-dodecanethiol was found to strongly suppress field enhancement in SNEM. • SAM of 1-dodecanethiol

  14. Motor commands for fast point-to-point arm movements are customized for small changes in inertial load.

    Science.gov (United States)

    Pinter, Ilona J; Bobbert, Maarten F; van Soest, A J Knoek; Smeets, Jeroen B J

    2011-12-01

    For repeated point-to-point arm movements it is often assumed that motor commands are customized in a trial-to-trial manner, based on previous endpoint error. To test this assumption, we perturbed movement execution without affecting the endpoint error by using a modest manipulation of inertia. Participants made point-to-point elbow flexion and extension movements in the horizontal plane, under the instruction to move as fast as possible from one target area to another. In selected trials the moment of inertia of the lower arm was increased or decreased by 25%. First, we found that an unexpected increase or decrease of inertia did not affect the open loop controlled part of the movement path (and thus endpoint error was not affected). Second, we found that when the increased or decreased inertia was presented repeatedly, after 5-11 trials motor commands were customized: the first 100ms of agonistic muscle activity in the smoothed and rectified electromyographic signal of agonistic muscles was higher for the high inertia compared to the low inertia. We conclude that endpoint error is not the only parameter that is used to evaluate if motor commands lead to movements as planned. PMID:21890379

  15. Point Cloud Based Change Detection - an Automated Approach for Cloud-based Services

    Science.gov (United States)

    Collins, Patrick; Bahr, Thomas

    2016-04-01

    The fusion of stereo photogrammetric point clouds with LiDAR data or terrain information derived from SAR interferometry has a significant potential for 3D topographic change detection. In the present case study latest point cloud generation and analysis capabilities are used to examine a landslide that occurred in the village of Malin in Maharashtra, India, on 30 July 2014, and affected an area of ca. 44.000 m2. It focuses on Pléiades high resolution satellite imagery and the Airbus DS WorldDEMTM as a product of the TanDEM-X mission. This case study was performed using the COTS software package ENVI 5.3. Integration of custom processes and automation is supported by IDL (Interactive Data Language). Thus, ENVI analytics is running via the object-oriented and IDL-based ENVITask API. The pre-event topography is represented by the WorldDEMTM product, delivered with a raster of 12 m x 12 m and based on the EGM2008 geoid (called pre-DEM). For the post-event situation a Pléiades 1B stereo image pair of the AOI affected was obtained. The ENVITask "GeneratePointCloudsByDenseImageMatching" was implemented to extract passive point clouds in LAS format from the panchromatic stereo datasets: • A dense image-matching algorithm is used to identify corresponding points in the two images. • A block adjustment is applied to refine the 3D coordinates that describe the scene geometry. • Additionally, the WorldDEMTM was input to constrain the range of heights in the matching area, and subsequently the length of the epipolar line. The "PointCloudFeatureExtraction" task was executed to generate the post-event digital surface model from the photogrammetric point clouds (called post-DEM). Post-processing consisted of the following steps: • Adding the geoid component (EGM 2008) to the post-DEM. • Pre-DEM reprojection to the UTM Zone 43N (WGS-84) coordinate system and resizing. • Subtraction of the pre-DEM from the post-DEM. • Filtering and threshold based classification of

  16. Tipping the balance: robustness of tip cell selection, migration and fusion in angiogenesis.

    Directory of Open Access Journals (Sweden)

    Katie Bentley

    2009-10-01

    Full Text Available Vascular abnormalities contribute to many diseases such as cancer and diabetic retinopathy. In angiogenesis new blood vessels, headed by a migrating tip cell, sprout from pre-existing vessels in response to signals, e.g., vascular endothelial growth factor (VEGF. Tip cells meet and fuse (anastomosis to form blood-flow supporting loops. Tip cell selection is achieved by Dll4-Notch mediated lateral inhibition resulting, under normal conditions, in an interleaved arrangement of tip and non-migrating stalk cells. Previously, we showed that the increased VEGF levels found in many diseases can cause the delayed negative feedback of lateral inhibition to produce abnormal oscillations of tip/stalk cell fates. Here we describe the development and implementation of a novel physics-based hierarchical agent model, tightly coupled to in vivo data, to explore the system dynamics as perpetual lateral inhibition combines with tip cell migration and fusion. We explore the tipping point between normal and abnormal sprouting as VEGF increases. A novel filopodia-adhesion driven migration mechanism is presented and validated against in vivo data. Due to the unique feature of ongoing lateral inhibition, 'stabilised' tip/stalk cell patterns show sensitivity to the formation of new cell-cell junctions during fusion: we predict cell fates can reverse. The fusing tip cells become inhibited and neighbouring stalk cells flip fate, recursively providing new tip cells. Junction size emerges as a key factor in establishing a stable tip/stalk pattern. Cell-cell junctions elongate as tip cells migrate, which is shown to provide positive feedback to lateral inhibition, causing it to be more susceptible to pathological oscillations. Importantly, down-regulation of the migratory pathway alone is shown to be sufficient to rescue the sprouting system from oscillation and restore stability. Thus we suggest the use of migration inhibitors as therapeutic agents for vascular

  17. Air Travel Health Tips

    Science.gov (United States)

    MENU Return to Web version Air Travel Health Tips Air Travel Health Tips How can I improve plane travel? Most people don't have any problems when ... and dosages of all of your medicines. The air in airplanes is dry, so drink nonalcoholic, decaffeinated ...

  18. Information technology: changing nursing processes at the point-of-care.

    Science.gov (United States)

    Courtney, Karen L; Demiris, George; Alexander, Greg L

    2005-01-01

    Changing societal demographics, increasing complexity in healthcare knowledge, and increasing nursing shortages have led healthcare strategists to call for a redesign of the healthcare system. Embedded within most redesign recommendations is the increased use of technology to make nursing practice more efficient. However, information technology (IT) has the potential to go beyond simple efficiency increases. If IT is perceived truly as a part of the redesign of healthcare delivery rather than simply the automation of existing processes, then it can change nursing processes within institutions and furthermore change the point-of-care between nurses and patients. Nursing adoption of technology within the workplace is a result of the interactions between technical skills, social acceptance, and workplace culture. Nursing needs for information not only influence their adoption of particular technologies but also shape their design. The objective of this article is to illustrate how IT can change not only nursing practice and processes but also the point-of-care. A case study of the use of IT by nurses in telehomecare is presented and administrative implications are discussed. PMID:16260995

  19. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

    Medline Plus

    Full Text Available ... the liver). Portal hypertension can also occur in children, although children are much less likely to require a TIPS. ... intentionally to solve the problem. Although extremely rare, children may also require a TIPS procedure. TIPS in ...

  20. Safety Tips: Basketball (For Parents)

    Science.gov (United States)

    ... Things to Know About Zika & Pregnancy Safety Tips: Basketball KidsHealth > For Parents > Safety Tips: Basketball Print A ... possible, make sure they follow these tips. Why Basketball Safety Is Important Fortunately, very few basketball injuries ...

  1. Effect of blade tip configuration on tip clearance loss of a centrifugal impeller

    Science.gov (United States)

    Ishida, Masahiro; Ueki, Hironobu; Senoo, Yasutoshi

    1989-06-01

    The effect of blade tip configuration on the tip clearance loss was examined experimentally using an unshrouded centrifugal impeller with backward-leaning blades. Tips with rounded edges, sharp square edges, and edges with end plates were tested. The observed tip clearance effects could be theoretically predicted by assuming reasonable values of the contraction coefficent alpha = 0.91 for the round edge, 0.73 for the sharp square edge, and 0.53 for the end-plate edge. The impeller efficiency was improved by about 1.5 point by reducing the contraction coefficient from 0.91 to 0.53. The effect of contraction coefficient on impeller efficiency depends on the ratio of leakage loss to the tip clearance loss. Improved efficiency for impellers with highly loaded blades is expected from reducing the contraction coefficient.

  2. Sharp Tips on the Atomic Force Microscope

    Science.gov (United States)

    2008-01-01

    This image shows the eight sharp tips of the NASA's Phoenix Mars Lander's Atomic Force Microscope, or AFM. The AFM is part of Phoenix's Microscopy, Electrochemistry, and Conductivity Analyzer, or MECA. The microscope maps the shape of particles in three dimensions by scanning them with one of the tips at the end of a beam. For the AFM image taken, the tip at the end of the upper right beam was used. The tip pointing up in the enlarged image is the size of a smoke particle at its base, or 2 microns. This image was taken with a scanning electron microscope before Phoenix launched on August 4, 2007. The AFM was developed by a Swiss-led consortium in collaboration with Imperial College London. The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is by NASA's Jet Propulsion Laboratory, Pasadena, Calif. Spacecraft development is by Lockheed Martin Space Systems, Denver.

  3. Three-point third-order problems with a sign-changing nonlinear term

    Directory of Open Access Journals (Sweden)

    Johnny Henderson

    2014-08-01

    Full Text Available In this article we study a well-known boundary value problem $$\\displaylines{ u'''(t = f(t, u(t, \\quad 0 1/2$. It is well-known that the standard method successfully applied to the semi-positone problem with $\\eta > 1/2$ does not work for $\\eta =1/2$ in the same setting. We treat the latter as a problem with a sign-changing term rather than a semi-positone problem. We apply Krasnosel'skii's fixed point theorem [4] to obtain positive solutions.

  4. Multi Weyl Points and the Sign Change of Their Topological Charges in Woodpile Photonic Crystals

    CERN Document Server

    Chang, Ming-Li; Chen, Wen-Jie; Chan, C T

    2016-01-01

    We show that Weyl points with topological charges 1 and 2 can be found in very simple chiral woodpile photonic crystals, which can be fabricated using current techniques down to the nano-scale. The sign of the topological charges can be tuned by changing the material parameters of the crystal, keeping the structure and the symmetry unchanged. The underlying physics can be understood using a tight binding model, which shows that the sign of the charge depends on the hopping range. Gapless surface states and their back-scattering immune properties are also demonstrated in these systems.

  5. Picture change error in quasirelativistic electron/spin density, Laplacian and bond critical points

    KAUST Repository

    Bučinský, Lukáš

    2014-06-01

    The change of picture of the quasirelativistic Hartree-Fock wave functions is considered for electron/spin densities, the negative Laplacian of electron density and the appropriate bond critical point characteristics from the Quantum Theory of Atoms In Molecules (QTAIM). [OsCl5(Hpz)]- and [RuCl5(NO)]2- transition metal complexes are considered. Both, scalar relativistic and spin-orbit effects have been accounted for using the Infinite Order Two Component (IOTC) Hamiltonian. Picture change error (PCE) correction in the electron and spin densities and the Laplacian of electron density are treated analytically. Generally, PCE is found significant only in the core region of the atoms for the electron/spin density as well as Laplacian.©2014 Elsevier B.V. All rights reserved.

  6. Small Stress Change Triggering a Big Earthquake: a Test of the Critical Point Hypothesis for Earthquakes

    Institute of Scientific and Technical Information of China (English)

    万永革; 吴忠良; 周公威

    2003-01-01

    Whether or not a small stress change can trigger a big earthquake is one of the most important problems related to the critical point hypothesis for earthquakes. We investigate global earthquakes with different focal mechanisms which have different levels of ambient shear stress. This ambient stress level is the stress level required by the earthquakes for their occurrence. Earthquake pairs are studied to see whether the occurrence of the preceding event encourages the occurrence of the succeeding one in terms of the Coulomb stress triggering. It is observed that the stress triggering effect produced by the change of Coulomb failure stress in the same order of magnitudes,about 10-2 MPa, is distinctly different for different focal mechanisms, and thus for different ambient stress levels.For non-strike-slip earthquakes with a relatively low ambient stress level, the triggering effect is more evident,while for strike-slip earthquakes with a relatively high ambient stress level, there is no evident triggering effect.This water level test provides an observational support to the critical point hypothesis for earthquakes.

  7. a Robust Registration Algorithm for Point Clouds from Uav Images for Change Detection

    Science.gov (United States)

    Al-Rawabdeh, A.; Al-Gurrani, H.; Al-Durgham, K.; Detchev, I.; He, F.; El-Sheimy, N.; Habib, A.

    2016-06-01

    Landslides are among the major threats to urban landscape and manmade infrastructure. They often cause economic losses, property damages, and loss of lives. Temporal monitoring data of landslides from different epochs empowers the evaluation of landslide progression. Alignment of overlapping surfaces from two or more epochs is crucial for the proper analysis of landslide dynamics. The traditional methods for point-cloud-based landslide monitoring rely on using a variation of the Iterative Closest Point (ICP) registration procedure to align any reconstructed surfaces from different epochs to a common reference frame. However, sometimes the ICP-based registration can fail or may not provide sufficient accuracy. For example, point clouds from different epochs might fit to local minima due to lack of geometrical variability within the data. Also, manual interaction is required to exclude any non-stable areas from the registration process. In this paper, a robust image-based registration method is introduced for the simultaneous evaluation of all registration parameters. This includes the Interior Orientation Parameters (IOPs) of the camera and the Exterior Orientation Parameters (EOPs) of the involved images from all available observation epochs via a bundle block adjustment with self-calibration. Next, a semi-global dense matching technique is implemented to generate dense 3D point clouds for each epoch using the images captured in a particular epoch separately. The normal distances between any two consecutive point clouds can then be readily computed, because the point clouds are already effectively co-registered. A low-cost DJI Phantom II Unmanned Aerial Vehicle (UAV) was customised and used in this research for temporal data collection over an active soil creep area in Lethbridge, Alberta, Canada. The customisation included adding a GPS logger and a Large-Field-Of-View (LFOV) action camera which facilitated capturing high-resolution geo-tagged images in two epochs

  8. Tips for Daily Living

    Science.gov (United States)

    ... After Stroke Weight Training After Stroke Tips for Improving Fine Motor Skills Functional Tone Management Arm Training Program Constraint-Induced Movement Therapy Emotional & Behavioral Challenges Self-Esteem after Stroke Post-Stroke Mood Disorders One-side ...

  9. Fast food tips

    Science.gov (United States)

    ... page: //medlineplus.gov/ency/patientinstructions/000105.htm Fast food tips To use the sharing features on this ... fast food. When You Go to a Fast Food Restaurant Knowing the amount of calories, fat, and ...

  10. Scaling in light scattering by sharp conical metal tips

    CERN Document Server

    Pors, Anders; Bozhevolnyi, Sergey I

    2016-01-01

    Using the electrostatic approximation, we analyze electromagnetic fields scattered by sharp conical metal tips, which are illuminated with light polarized along the tip axis. We establish scaling relations for the scattered field amplitude and phase, whose validity is verified with numerical simulations. Analytic expressions for the wavelength, at which the scattered field near the tip changes its direction, and field decay near the tip extremity are obtained, relating these characteristics to the cone angle and metal permittivity. The results obtained have important implications to various tip-enhanced phenomena, ranging from Raman and scattering near-field imaging to photoemission spectroscopy and nano-optical trapping.

  11. Influence of rotor blade tip shape on tip vortex shedding - An unsteady, inviscid analysis

    Science.gov (United States)

    Maskew, B.

    1980-01-01

    An unsteady potential flow panel method is described based on a time-stepping procedure and using planar quadrilateral panels to represent the surface of thick blades. Each panel has a constant source and doublet distribution and a central control point where an internal Dirichlet boundary condition is applied. The method includes detail paneling around the tip edge and offers the facility of prescribing a tip-edge separation. Preliminary results are shown for four blade tip shapes which are treated as semi-span wings oscillating in pitch about a mean angle of attack of 6 deg. Further work is planned for the wake model before proceeding to higher angles of attack.

  12. A procedure for the change point problem in parametric models based on phi-divergence test-statistics

    CERN Document Server

    Batsidis, Apostolos; Pardo, Leandro; Zografos, Konstantinos

    2011-01-01

    This paper studies the change point problem for a general parametric, univariate or multivariate family of distributions. An information theoretic procedure is developed which is based on general divergence measures for testing the hypothesis of the existence of a change. For comparing the accuracy of the new test-statistic a simulation study is performed for the special case of a univariate discrete model. Finally, the procedure proposed in this paper is illustrated through a classical change-point example.

  13. A novel method for fast Change-Point detection on simulated time series and electrocardiogram data.

    Directory of Open Access Journals (Sweden)

    Jin-Peng Qi

    Full Text Available Although Kolmogorov-Smirnov (KS statistic is a widely used method, some weaknesses exist in investigating abrupt Change Point (CP problems, e.g. it is time-consuming and invalid sometimes. To detect abrupt change from time series fast, a novel method is proposed based on Haar Wavelet (HW and KS statistic (HWKS. First, the two Binary Search Trees (BSTs, termed TcA and TcD, are constructed by multi-level HW from a diagnosed time series; the framework of HWKS method is implemented by introducing a modified KS statistic and two search rules based on the two BSTs; and then fast CP detection is implemented by two HWKS-based algorithms. Second, the performance of HWKS is evaluated by simulated time series dataset. The simulations show that HWKS is faster, more sensitive and efficient than KS, HW, and T methods. Last, HWKS is applied to analyze the electrocardiogram (ECG time series, the experiment results show that the proposed method can find abrupt change from ECG segment with maximal data fluctuation more quickly and efficiently, and it is very helpful to inspect and diagnose the different state of health from a patient's ECG signal.

  14. Picture change error in quasirelativistic electron/spin density, Laplacian and bond critical points

    Energy Technology Data Exchange (ETDEWEB)

    Bučinský, Lukáš, E-mail: lukas.bucinsky@stuba.sk [Slovak University of Technology, FCHPT, Institute of Physical Chemistry and Chemical Physics, Radlinskeho 9, Bratislava SK-812 37 (Slovakia); Kucková, Lenka; Malček, Michal; Kožíšek, Jozef; Biskupič, Stanislav [Slovak University of Technology, FCHPT, Institute of Physical Chemistry and Chemical Physics, Radlinskeho 9, Bratislava SK-812 37 (Slovakia); Jayatilaka, Dylan [University of Western Australia, Department of Chemistry, 35 Stirling Hwy, Crawley, WA 6009 (Australia); Büchel, Gabriel E. [University of Vienna, Institute of Inorganic Chemistry, Währinger Str. 42, A-1090 Vienna (Austria); King Abdullah University of Science and Technology, Division for Physical Sciences and Engineering and KAUST Catalysis Center, Thuwal (Saudi Arabia); Arion, Vladimir B. [University of Vienna, Institute of Inorganic Chemistry, Währinger Str. 42, A-1090 Vienna (Austria)

    2014-06-25

    Highlights: • Quasirelativistic study of electron density topology of Os and Ru complexes. • Electron/spin densities and negative Laplacian of electron density presented. • Analytic correction of picture change error at IOTC level. • Relativistic and spin–orbit effects are considered, IOTC vs. DKH2 compared. - Abstract: The change of picture of the quasirelativistic Hartree–Fock wave functions is considered for electron/spin densities, the negative Laplacian of electron density and the appropriate bond critical point characteristics from the Quantum Theory of Atoms In Molecules (QTAIM). [OsCl{sub 5}(Hpz)]{sup −} and [RuCl{sub 5}(NO)]{sup 2−} transition metal complexes are considered. Both, scalar relativistic and spin–orbit effects have been accounted for using the Infinite Order Two Component (IOTC) Hamiltonian. Picture change error (PCE) correction in the electron and spin densities and the Laplacian of electron density are treated analytically. Generally, PCE is found significant only in the core region of the atoms for the electron/spin density as well as Laplacian.

  15. Discrete Software Reliability Growth Modeling for Errors of Different Severity Incorporating Change-point Concept

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Several software reliability growth models (SRGM) have been developed to monitor the reliability growth during the testing phase of software development. In most of the existing research available in the literatures, it is considered that a similar testing effort is required on each debugging effort. However, in practice, different types of faults may require different amounts of testing efforts for their detection and removal. Consequently, faults are classified into three categories on the basis of severity: simple, hard and complex. This categorization may be extended to r type of faults on the basis of severity. Although some existing research in the literatures has incorporated this concept that fault removal rate (FRR) is different for different types of faults, they assume that the FRR remains constant during the overall testing period. On the contrary, it has been observed that as testing progresses, FRR changes due to changing testing strategy, skill, environment and personnel resources. In this paper, a general discrete SRGM is proposed for errors of different severity in software systems using the change-point concept. Then, the models are formulated for two particular environments. The models were validated on two real-life data sets. The results show better fit and wider applicability of the proposed models as to different types of failure datasets.

  16. Change of carrier density at the pseudogap critical point of a cuprate superconductor.

    Science.gov (United States)

    Badoux, S; Tabis, W; Laliberté, F; Grissonnanche, G; Vignolle, B; Vignolles, D; Béard, J; Bonn, D A; Hardy, W N; Liang, R; Doiron-Leyraud, N; Taillefer, Louis; Proust, Cyril

    2016-03-10

    The pseudogap is a partial gap in the electronic density of states that opens in the normal (non-superconducting) state of cuprate superconductors and whose origin is a long-standing puzzle. Its connection to the Mott insulator phase at low doping (hole concentration, p) remains ambiguous and its relation to the charge order that reconstructs the Fermi surface at intermediate doping is still unclear. Here we use measurements of the Hall coefficient in magnetic fields up to 88 tesla to show that Fermi-surface reconstruction by charge order in the cuprate YBa2Cu3Oy ends sharply at a critical doping p = 0.16 that is distinctly lower than the pseudogap critical point p* = 0.19 (ref. 11). This shows that the pseudogap and charge order are separate phenomena. We find that the change in carrier density n from n = 1 + p in the conventional metal at high doping (ref. 12) to n = p at low doping (ref. 13) starts at the pseudogap critical point. This shows that the pseudogap and the antiferromagnetic Mott insulator are linked.

  17. Changes in Sleep With Auricular Point Acupressure for Chronic Low Back Pain.

    Science.gov (United States)

    Yeh, Chao Hsing; Suen, Lorna Kwai-Ping; Shen, Juan; Chien, Lung-Chang; Liang, Zhan; Glick, Ronald M; Morone, Natalia E; Chasens, Eileen R

    2016-01-01

    The purpose of this study was to report sleep quality from 4 weeks of auricular point acupressure that was designed for chronic low back pain and determine the relationship between pain intensity and sleep quality. Participants were randomized into the APA group (n = 30) or the sham-APA group (n = 31). At baseline assessment, 87% of the participants reported poor sleep quality. Participants who received APA had decreased daytime disturbance and improved global Pittsburgh Sleep Quality Index scores at end of intervention (EOI) and 1-month follow up compared to participants in the sham-APA group. For the APA group, both the sleep duration and wake after sleep onset decreased gradually during the 4-week APA (0.56% and 0.23% daily change, respectively). PMID:26244591

  18. On Compound Poisson Processes Arising in Change-Point Type Statistical Models as Limiting Likelihood Ratios

    CERN Document Server

    Dachian, Serguei

    2010-01-01

    Different change-point type models encountered in statistical inference for stochastic processes give rise to different limiting likelihood ratio processes. In a previous paper of one of the authors it was established that one of these likelihood ratios, which is an exponential functional of a two-sided Poisson process driven by some parameter, can be approximated (for sufficiently small values of the parameter) by another one, which is an exponential functional of a two-sided Brownian motion. In this paper we consider yet another likelihood ratio, which is the exponent of a two-sided compound Poisson process driven by some parameter. We establish, that similarly to the Poisson type one, the compound Poisson type likelihood ratio can be approximated by the Brownian type one for sufficiently small values of the parameter. We equally discuss the asymptotics for large values of the parameter and illustrate the results by numerical simulations.

  19. Morphological changes at the interface of the nickel-yttria stabilized zirconia point electrode

    DEFF Research Database (Denmark)

    Aaberg, Rolf Jarle; Tunold, Reidar; Mogensen, Mogens Bjerg;

    1998-01-01

    The H-2-H2O, Ni/YSZ point electrode has been investigated using long-term potential step measurements and impedance spectroscopy at 1273 K. Morphological and structural changes at the electrode interface were evaluated by electron microscopy, energy dispersive X-ray analysis, and Raman spectroscopy...... of dispersed metal particles reduced the TPB length, and accordingly the cathodic current. In addition to the morphological modifications, the catalytic properties of the surfaces were significantly altered as the electrode was polarized. Transformation from cubic to tetragonal YSZ, due to segregation...... of the material, was observed on the surface of the electrolyte when the sample was kept at working conditions for long periods of time (135 days). The passage of current was not found to generate any permanent phase transformation in the YSZ....

  20. Emission Characteristics of Ion-Implanted Silicon Emitter Tips

    Science.gov (United States)

    Hirano, Takayuki; Kanemaru, Seigo; Tanoue, Hisao; Itoh, Junji

    1995-12-01

    An ion implantation technique has been applied to control the energy band structure of Si field-emitter tip surface. B+ or P+ ions were implanted after fabrication of a gated emitter structure. No changes in emitter structure were observed after ion implantation and successive annealing at 800° C. Current-voltage ( I-V ) characteristics of n, p, p/n and n/p emitter tips were measured: p/n indicates an n-type tip with B+ ions implanted into the tip surface. It was found from the experimental results that n and p/n tips had I-V characteristics in agreement with the Fowler-Nordheim theory. The p and n/p tips, on the other hand, exhibited a current saturation property in high electric field. The present saturation mechanism is explained by considering the energy band structure of the tip surface.

  1. On the phi-divergence test statistics for the change point problem in a sequence of exponentially distributed random variables

    CERN Document Server

    Apostolos, Batsidis; Leandro, Pardo; Konstantinos, Zografos

    2011-01-01

    Recently Batsidis et al. (2011) have presented a new procedure based on divergence measures for testing the hypothesis of the existence of a change point in exponential populations. A simulation study was carried out using the asymptotic critical points obtained from the asymptotic distribution of the new test statistics introduced. The main purpose of this paper is to use the behavior of the test statistics introduced in the cited paper of Batsidis et al. (2011) using simulated critical points.

  2. Human Health and Climate Change: Leverage Points for Adaptation in Urban Environments

    Directory of Open Access Journals (Sweden)

    Monica Zarafu

    2012-06-01

    Full Text Available The design of adaptation strategies that promote urban health and well-being in the face of climate change requires an understanding of the feedback interactions that take place between the dynamical state of a city, the health of its people, and the state of the planet. Complexity, contingency and uncertainty combine to impede the growth of such systemic understandings. In this paper we suggest that the collaborative development of conceptual models can help a group to identify potential leverage points for effective adaptation. We describe a three-step procedure that leads from the development of a high-level system template, through the selection of a problem space that contains one or more of the group’s adaptive challenges, to a specific conceptual model of a sub-system of importance to the group. This procedure is illustrated by a case study of urban dwellers’ maladaptive dependence on private motor vehicles. We conclude that a system dynamics approach, revolving around the collaborative construction of a set of conceptual models, can help communities to improve their adaptive capacity, and so better meet the challenge of maintaining, and even improving, urban health in the face of climate change.

  3. An efficient and robust test for a change-point in correlation

    CERN Document Server

    Dehling, Herold; Wendler, Martin; Wied, Dominik

    2012-01-01

    For a bivariate time series ((X_i,Y_i))_{i=1,...,n} we want to detect whether the correlation between X_i and Y_i stays constant for all i = 1,...,n. We propose a nonparametric change-point test statistic based on Kendall's tau and derive its asymptotic distribution under the null hypothesis of no change. The asymptotic distribution depends on the long run variance of Kendall's tau, for which we propose an estimator and show its consistency. Kendall's tau possesses a high efficiency at the normal distribution, as compared to the normal maximum likelihood estimator, Pearson's moment correlation coefficient. Contrary to Pearson's correlation coefficient, it has excellent robustness properties and shows no loss in efficiency at heavy-tailed distributions. We assume the data ((X_i,Y_i))_{i=1,...,n} to be stationary and P-near epoch dependent on an absolutely regular process. The P-near epoch dependence condition constitutes a generalization of the usually considered L_p-near epoch dependence, p >= 1, that does no...

  4. Human Health and Climate Change: Leverage Points for Adaptation in Urban Environments

    Science.gov (United States)

    Proust, Katrina; Newell, Barry; Brown, Helen; Capon, Anthony; Browne, Chris; Burton, Anthony; Dixon, Jane; Mu, Lisa; Zarafu, Monica

    2012-01-01

    The design of adaptation strategies that promote urban health and well-being in the face of climate change requires an understanding of the feedback interactions that take place between the dynamical state of a city, the health of its people, and the state of the planet. Complexity, contingency and uncertainty combine to impede the growth of such systemic understandings. In this paper we suggest that the collaborative development of conceptual models can help a group to identify potential leverage points for effective adaptation. We describe a three-step procedure that leads from the development of a high-level system template, through the selection of a problem space that contains one or more of the group’s adaptive challenges, to a specific conceptual model of a sub-system of importance to the group. This procedure is illustrated by a case study of urban dwellers’ maladaptive dependence on private motor vehicles. We conclude that a system dynamics approach, revolving around the collaborative construction of a set of conceptual models, can help communities to improve their adaptive capacity, and so better meet the challenge of maintaining, and even improving, urban health in the face of climate change. PMID:22829795

  5. Tip Streaming from a Drop in the Presence of Surfactants

    International Nuclear Information System (INIS)

    Drop breakup in a linear extensional flow is simulated numerically using a nonlinear model for the surface tension that accounts for maximum packing at the interface. Surface convection sweeps surfactant to the drop poles, where it accumulates and drives the surface tension to near zero. The drop assumes a transient shape with highly pointed tips. From these tips, thin liquid threads are pulled. Subsequently, small, surfactant-rich droplets are emitted from the termini of these threads. The scale of the shed drops depends on the initial surfactant coverage. Dilute initial coverage leads to tip streaming, while high initial coverage leads to the tip dropping breakup mode

  6. Dynamic Performance of Maximum Power Point Trackers in TEG Systems Under Rapidly Changing Temperature Conditions

    Science.gov (United States)

    Man, E. A.; Sera, D.; Mathe, L.; Schaltz, E.; Rosendahl, L.

    2016-03-01

    Characterization of thermoelectric generators (TEG) is widely discussed and equipment has been built that can perform such analysis. One method is often used to perform such characterization: constant temperature with variable thermal power input. Maximum power point tracking (MPPT) methods for TEG systems are mostly tested under steady-state conditions for different constant input temperatures. However, for most TEG applications, the input temperature gradient changes, exposing the MPPT to variable tracking conditions. An example is the exhaust pipe on hybrid vehicles, for which, because of the intermittent operation of the internal combustion engine, the TEG and its MPPT controller are exposed to a cyclic temperature profile. Furthermore, there are no guidelines on how fast the MPPT must be under such dynamic conditions. In the work discussed in this paper, temperature gradients for TEG integrated in several applications were evaluated; the results showed temperature variation up to 5°C/s for TEG systems. Electrical characterization of a calcium-manganese oxide TEG was performed at steady-state for different input temperatures and a maximum temperature of 401°C. By using electrical data from characterization of the oxide module, a solar array simulator was emulated to perform as a TEG. A trapezoidal temperature profile with different gradients was used on the TEG simulator to evaluate the dynamic MPPT efficiency. It is known that the perturb and observe (P&O) algorithm may have difficulty accurately tracking under rapidly changing conditions. To solve this problem, a compromise must be found between the magnitude of the increment and the sampling frequency of the control algorithm. The standard P&O performance was evaluated experimentally by using different temperature gradients for different MPPT sampling frequencies, and efficiency values are provided for all cases. The results showed that a tracking speed of 2.5 Hz can be successfully implemented on a TEG

  7. A statistical model investigating the prevalence of tuberculosis in New York City using counting processes with two change-points.

    Science.gov (United States)

    Achcar, J A; Martinez, E Z; Ruffino-Netto, A; Paulino, C D; Soares, P

    2008-12-01

    We considered a Bayesian analysis for the prevalence of tuberculosis cases in New York City from 1970 to 2000. This counting dataset presented two change-points during this period. We modelled this counting dataset considering non-homogeneous Poisson processes in the presence of the two-change points. A Bayesian analysis for the data is considered using Markov chain Monte Carlo methods. Simulated Gibbs samples for the parameters of interest were obtained using WinBugs software.

  8. Atom probe trajectory mapping using experimental tip shape measurements.

    Science.gov (United States)

    Haley, D; Petersen, T; Ringer, S P; Smith, G D W

    2011-11-01

    Atom probe tomography is an accurate analytical and imaging technique which can reconstruct the complex structure and composition of a specimen in three dimensions. Despite providing locally high spatial resolution, atom probe tomography suffers from global distortions due to a complex projection function between the specimen and detector which is different for each experiment and can change during a single run. To aid characterization of this projection function, this work demonstrates a method for the reverse projection of ions from an arbitrary projection surface in 3D space back to an atom probe tomography specimen surface. Experimental data from transmission electron microscopy tilt tomography are combined with point cloud surface reconstruction algorithms and finite element modelling to generate a mapping back to the original tip surface in a physically and experimentally motivated manner. As a case study, aluminium tips are imaged using transmission electron microscopy before and after atom probe tomography, and the specimen profiles used as input in surface reconstruction methods. This reconstruction method is a general procedure that can be used to generate mappings between a selected surface and a known tip shape using numerical solutions to the electrostatic equation, with quantitative solutions to the projection problem readily achievable in tens of minutes on a contemporary workstation. PMID:22004277

  9. Research on Monitoring Area Division of Quality Grade Changes in County Cultivated Land and Technology of Deploying Monitoring Point

    OpenAIRE

    Wei, Wei; Liao, Lijun; Yu, Jianxin

    2013-01-01

    It is an important means in management of improving both the quality and quantity of cultivated land to monitor grade changes in cultivated land quality. How to deploy monitoring network system and its point reasonably and roundly are the key to the technology of monitoring grade changes in cultivated land quality by monitoring grade changes in cultivated land quality dynamically in order to obtain the information to the index of cultivated land quality and its changes based on the existing a...

  10. Desensitization of over tip leakage in an axial turbine rotor by tip surface coolant injection

    Science.gov (United States)

    Rao, Nikhil Molahally

    Mechanical energy extraction in axial flow turbine rotors occurs through a change in angular momentum of the working fluid. The gap between the turbine rotor and the stationary casing is referred to as the tip gap. High pressure turbine blades are typically un-shrouded and pressure driven flow through the tip gap is termed as over tip leakage. Over tip leakage reduces efficiency of the turbine stage and also causes thermal distress to blade tip surfaces. The gap height typically increases over the operational life of a turbine, leading to increased efficiency drop. The thermal load on the tip surface also increases with increasing gap height and is exacerbated by the radial transport of high temperature fluid found in the core of the combustor exit flow. Thus over tip leakage not only decreases stage efficiency, but also constrains it by limiting the maximum cycle temperature. Reducing the sensitivity of turbine performance to the effects of the tip gap is termed Tip Desensitization. An experimental investigation of tip desensitization through coolant injection from a tip surface trench was conducted in a large scale, low speed, rotating research turbine facility. Five out of twenty nine rotor blades, referred to as cooled blades, are provided with coolant injection at four locations, at 61%, 71%, 81%, and 91% blade tip axial chord length. At each of the first three locations the coolant jets are directed towards the blade pressure-side, while coolant is exhausted radially at the last location. The sensitivity of total pressure defect, due to over tip leakage, to tip gap height is reduced by both coolant injection and roughening of the casing surface. The total pressure defect due to the large gap height of 1.40% blade height is reduced to levels comparable to the defect due to a gap height of 0.72% blade height. The strong total pressure gradient that characterizes the leakage vortex due to the gap height of 1.40% blade height is considerably diminished by both

  11. Minimal $f$-divergence martingale measures and optimal portfolios for exponential Levy models with a change-point

    CERN Document Server

    Cawston, S

    2010-01-01

    We consider the exponential Levy models and we study the conditions under which f-minimal equivalent martingale measure preserves Levy property. Then we give a general formula for optimal strategy in a sense of utility maximization. Finally, we study change-point exponential Levy models, namely we give the conditions for the existence of f-minimal equivalent martingale measure and we obtain a general formula for optimal strategy from point of view of the utility maximization. We illustrate our results considering Black-Scholes model with change-point.

  12. Cytological changes in meristematic cells of Allium cepa L. root tip treated with extracts from callus of Catharanthus roseus (L. G. Don

    Directory of Open Access Journals (Sweden)

    Agnieszka Pietrosiuk

    2014-02-01

    Full Text Available The effect of an ethanolic extract from callus of Catharanthus roseus on Allium cepa root cells divisions was investigated. Two lines: white and green callus, were established on solid B5 medium with IAA 1 mg/l and kinetin 0.1 mg/l. The HPLC analysis of callus extracts showed the presence of indole alkaloids, however not known pharmacologically active alkaloids or derivatives used in semisynthesis (vinblastine, ajmalicine, serpentine, yohimbine, vindoline and catharanthine have been found. The ethanolic extract of C. roseus callus inhibited the number of mitoses in Allium cepa root tip cells. Short (1-3 hours treatment resulted in an increase in the index of late prophases, with characteristic light spaces, and the index of metaphases with twisted chromosomes forming an equatorial plate or irregular structures of c-metaphases. At the same time, the percentage of anaphases and telophases decreased significantly. Longer treatment of the root tip inhibited mitotic activity, stopping it completely already after 12 hours. Interphase nuclei became at first denser and homogeneous, eventually their structure became , partitioned into zones and formation of chromatin territories, with distinct large nucleoli has been observed. Electron microscope observations revealed well developed rough endoplasmic reticulum and thick, invaginating cell membrane.

  13. "Everything Changed": Relational Turning Point Events in College Teacher-Student Relationships from Teachers' Perspectives

    Science.gov (United States)

    Docan-Morgan, Tony

    2011-01-01

    The purpose of this study was to investigate college teachers' experiences of relational turning points with their students, as well as how these turning point events may affect teacher outcomes. Teachers who were able to identify a relational turning point event with a student (n=306, 78.5% of the overall sample) completed open- and closed-ended…

  14. Relocalization of human chromatin remodeling cofactor TIP48 in mitosis

    International Nuclear Information System (INIS)

    TIP48 is a highly conserved eukaryotic AAA+ protein which is an essential cofactor for several complexes involved in chromatin acetylation and remodeling, transcriptional and developmental regulation and nucleolar organization and trafficking. We show that TIP48 abundance in HeLa cells did not change during the cell cycle, nor did its distribution in various biochemical fractions. However, we observed distinct changes in the subcellular localization of TIP48 during M phase using immunofluorescence microscopy. Our studies demonstrate that in interphase cells TIP48 was found mainly in the nucleus and exhibited a distinct localization in the nuclear periphery. As the cells entered mitosis, TIP48 was excluded from the condensing chromosomes but showed association with the mitotic apparatus. During anaphase, some TIP48 was detected in the centrosome colocalizing with tubulin but the strongest staining appeared in the mitotic equator associated with the midzone central spindle. Accumulation of TIP48 in the midzone and the midbody was observed in late telophase and cytokinesis. This redeployment of TIP48 during anaphase and cytokinesis was independent of microtubule assembly. The relocation of endogenous TIP48 to the midzone/midbody under physiological conditions suggests a novel and distinct function for TIP48 in mitosis and possible involvement in the exit of mitosis

  15. Tip-modified Propellers

    DEFF Research Database (Denmark)

    Andersen, Poul

    1999-01-01

    The paper deals with tip-modified propellers and the methods which, over a period of two decades, have been applied to develop such propellers. The development is driven by the urge to increase the efficiency of propellers and can be seen as analogous to fitting end plates and winglets to aircraft...

  16. Tips for Getting a Proper Diagnosis of an Autoimmune Disease

    Science.gov (United States)

    Tips for Getting a Proper Diagnosis of an Autoimmune Disease Do your own family medical history. Take an ... research points to a genetic component in most autoimmune diseases, you should know the health histories of your ...

  17. Safety Tips: Baseball (For Parents)

    Science.gov (United States)

    ... Story" 5 Things to Know About Zika & Pregnancy Safety Tips: Baseball KidsHealth > For Parents > Safety Tips: Baseball ... sport, and it's fun. View Survey Why Baseball Safety Is Important Baseball is by no means a ...

  18. Academisch schrijven: Tips and tricks

    NARCIS (Netherlands)

    Wetzels, Sandra

    2012-01-01

    Wetzels, S. A. J. (2012, 14 April). Academisch schrijven: Tips and tricks [Academic writing: Tips and tricks]. Presentation at sprint meeting 'De praktijk van actief leren' from the master programme Learning Sciences, Eindhoven, The Netherlands.

  19. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

    Medline Plus

    Full Text Available ... TIPS is a minimally invasive procedure that typically has a shorter recovery time than surgery. Your TIPS ... on future liver transplantation surgery because the abdomen has not been entered, thus there is no scar ...

  20. AERODYNAMICS OF WING TIP SAILS

    OpenAIRE

    MUSHTAK AL-ATABI

    2006-01-01

    Observers have always been fascinated by soaring birds. An interesting feature of these birds is the existence of few feathers extending from the tip of the wing. In this paper, small lifting surfaces were fitted to the tip of a NACA0012 wing in a fashion similar to that of wing tip feathers. Experimental measurements of induced drag, longitudinal static stability and trailing vortex structure were obtained.The tests showed that adding wing tip surfaces (sails) decreased the induced drag fact...

  1. Economic Behavior of Restaurant Tipping

    OpenAIRE

    Tin-Chun Lin

    2007-01-01

    This paper offers a thoughtful discussion of social norms and alternative economic viewpoints and analysis of restaurant tipping behavior. A survey of Louisiana residents was conducted to collect public opinions about tipping. The analysis suggests that social norms are indeed the primary reason for diner tipping. As long as consumer behavior is guided by social norms, social norms will costs for diners. The conclusion suggests that if customer's tipping behavior were completely guided by soc...

  2. 21 CFR 872.6650 - Massaging pick or tip for oral hygiene.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Massaging pick or tip for oral hygiene. 872.6650... (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Miscellaneous Devices § 872.6650 Massaging pick or tip for oral hygiene. (a) Identification. A massaging pick or tip for oral hygiene is a rigid, pointed device...

  3. Research on Monitoring Area Division of Quality Grade Changes in County Cultivated Land and Technology of Deploying Monitoring Point

    Institute of Scientific and Technical Information of China (English)

    Wei; WEI; Lijun; LIAO; Jianxin; YU

    2013-01-01

    It is an important means in management of improving both the quality and quantity of cultivated land to monitor grade changes in cultivated land quality. How to deploy monitoring network system and its point reasonably and roundly are the key to the technology of monitoring grade changes in cultivated land quality by monitoring grade changes in cultivated land quality dynamically in order to obtain the information to the index of cultivated land quality and its changes based on the existing achievements of farmland classification and grading. Spatial analysis method is used to demarcate monitoring area and deploy monitoring point according to ARCGIS,of which the result can meet the demand for monitoring grade changes in cultivated land.

  4. Study on leakage flow characteristics of radial inflow turbines at rotor tip clearance

    Institute of Scientific and Technical Information of China (English)

    DENG QingHua; NIU JiuFang; FENG ZhenPing

    2008-01-01

    Tip clearance leakage flow in a radial inflow turbine rotor for microturbines under the stage environment is investigated using a three-dimensional viscous flow simulation. The results indicate that the scraping flow caused by relative motion between casing and rotor tip, and the pressure difference between pressure side and suction side at rotor tip, play important roles in tip clearance leakage flow. The more the rotor tip speed increases and tip clearance height decreases, the more the scraping effect acta. Though the leakage velocity of tip clearance at midsection and exducer regions changes less when the rotor rotational speed is changing, the distance between passage vortex and rotor suction side varies in evidence. Main leakage flow rate of tip clearance takes place at region of exducer tip and some seal configurations will be quite effective for cutting leakage flow if these configurations are arranged over midsection and exducer of the radial inflow rotor.

  5. Study on leakage flow characteristics of radial inflow turbines at rotor tip clearance

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Tip clearance leakage flow in a radial inflow turbine rotor for microturbines under the stage environment is investigated using a three-dimensional viscous flow simulation. The results indicate that the scraping flow caused by relative motion between casing and rotor tip, and the pressure difference between pressure side and suction side at rotor tip, play important roles in tip clearance leakage flow. The more the rotor tip speed increases and tip clearance height decreases, the more the scraping effect acts. Though the leakage velocity of tip clearance at midsection and exducer regions changes less when the rotor rotational speed is changing, the distance between passage vortex and rotor suction side varies in evidence. Main leakage flow rate of tip clearance takes place at region of exducer tip and some seal configurations will be quite effective for cutting leakage flow if these configurations are arranged over midsection and exducer of the radial inflow rotor.

  6. Light depolarization induced by metallic tips in apertureless near-field optical microscopy and tip-enhanced Raman spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Gucciardi, P G [CNR-Istituto per i Processi Chimico-Fisici, sezione Messina, Salita Sperone, Contrada Papardo, I-98158 Faro Superiore, Messina (Italy); Lopes, M; Deturche, R; Julien, C; Barchiesi, D; Chapelle, M Lamy de la [Institut Charles Delaunay-CNRS FRE 2848, Laboratoire de Nanotechnologie et d' Instrumentation Optique, Universite de Technologie de Troyes, 12 rue Marie Curie, BP2060, 10010 Troyes (France)

    2008-05-28

    We have investigated the depolarization effects of light scattered by sharp tips used for apertureless near-field optical microscopy. Dielectric and metal coated tips have been investigated and depolarization factors between 5 and 30% have been measured, changing as a function of the incident light polarization and of the tip shape. The experimental results are in good agreement with theoretical calculations performed by the finite element method, giving a near-field depolarization factor close to 10%. The effect of depolarization has been investigated in polarized tip-enhanced Raman spectroscopy (TERS) experiments; the depolarization gives rise to forbidden Raman modes in Si crystals.

  7. Final Technical Report: Electrohydrodynamic Tip Streaming

    Energy Technology Data Exchange (ETDEWEB)

    Basaran, Osman [Purdue Univ., West Lafayette, IN (United States)

    2016-01-06

    When subjected to strong electric fields, liquid drops and films form conical tips and emit thin jets from their tips. Such electrodydrodynamic (EDH) tip streaming or cone-jetting phenomena, which are sometimes referred to as electrospraying, occur widely in nature, e.g., in ejection of streams of small charged drops from pointed tips of raindrops in thunderclouds, and technology, e.g., in electrospray mass spectrometry or electric field-driven solvent extraction. More recently, EHD cone-jetting has emerged as a powerful technique for direct printing of solar cells, micro- and nano- particle production, and microencapsulation for controlled release. In many of the aforementioned situations, of equal importance to the processes by which one drop disintegrates to form several drops are those by which (a) two drops come together and coalesce and (b) two drops are coupled to form a double droplet system (DDS) or a capillary switch (CS). the main objective of this research program is to advance through simulation, theory, and experiment the breakup, coalescence, and oscillatory dynamics of single and pairs of charged as well as uncharged drops.

  8. Method to detect the end-point for PCR DNA amplification using an ionically labeled probe and measuring impedance change

    Science.gov (United States)

    Miles, Robin R.; Belgrader, Phillip; Fuller, Christopher D.

    2007-01-02

    Impedance measurements are used to detect the end-point for PCR DNA amplification. A pair of spaced electrodes are located on a surface of a microfluidic channel and an AC or DC voltage is applied across the electrodes to produce an electric field. An ionically labeled probe will attach to a complementary DNA segment, and a polymerase enzyme will release the ionic label. This causes the conductivity of the solution in the area of the electrode to change. This change in conductivity is measured as a change in the impedance been the two electrodes.

  9. Integrated safety management as a starting point for working environmental changes

    DEFF Research Database (Denmark)

    Pedersen, Louise Møller; Nielsen, Kent

    2013-01-01

    Organizations: The effective management of organizational change involves understanding and appreciating the complex interactions of technology, people, organizations, economical factors, legislation, and aspects of cultural, physical, and psychological context. The behavior based and culture based......, which are can be diffused and disseminated throughout the organization and thereby potentially create cultural change. Communication and mutual trust between managers and workers are essential for the process to succeed. Intervention methods: The integrated approach to safety management can...... approaches to safety are two seemingly incompatible approaches to creating organizational change in safety performance. However, combined, the two approaches may provide a new perspective on conducting effective and healthy organizational changes. Approach to change: DeJoy has proposed an integrative...

  10. Point pattern match-based change detection in a constellation of previously detected objects

    Energy Technology Data Exchange (ETDEWEB)

    Paglieroni, David W.

    2016-06-07

    A method and system is provided that applies attribute- and topology-based change detection to objects that were detected on previous scans of a medium. The attributes capture properties or characteristics of the previously detected objects, such as location, time of detection, detection strength, size, elongation, orientation, etc. The locations define a three-dimensional network topology forming a constellation of previously detected objects. The change detection system stores attributes of the previously detected objects in a constellation database. The change detection system detects changes by comparing the attributes and topological consistency of newly detected objects encountered during a new scan of the medium to previously detected objects in the constellation database. The change detection system may receive the attributes of the newly detected objects as the objects are detected by an object detection system in real time.

  11. AERODYNAMICS OF WING TIP SAILS

    Directory of Open Access Journals (Sweden)

    MUSHTAK AL-ATABI

    2006-06-01

    Full Text Available Observers have always been fascinated by soaring birds. An interesting feature of these birds is the existence of few feathers extending from the tip of the wing. In this paper, small lifting surfaces were fitted to the tip of a NACA0012 wing in a fashion similar to that of wing tip feathers. Experimental measurements of induced drag, longitudinal static stability and trailing vortex structure were obtained.The tests showed that adding wing tip surfaces (sails decreased the induced drag factor and increased the longitudinal static stability. Results identified two discrete appositely rotated tip vortices and showed the ability of wing tip surfaces to break them down and to diffuse them.

  12. Changing the values of parameters on lot size reorder point model

    Directory of Open Access Journals (Sweden)

    Chang Hung-Chi

    2003-01-01

    Full Text Available The Just-In-Time (JIT philosophy has received a great deal of attention. Several actions such as improving quality, reducing setup cost and shortening lead time have been recognized as effective ways to achieve the underlying goal of JIT. This paper considers the partial backorders, lot size reorder point inventory system with an imperfect production process. The objective is to simultaneously optimize the lot size, reorder point, process quality, setup cost and lead time, constrained on a service level. We assume the explicit distributional form of lead time demand is unknown but the mean and standard deviation are given. The minimax distribution free approach is utilized to solve the problem and a numerical example is provided to illustrate the results. .

  13. Future PMPs Estimation in Korea under AR5 RCP 8.5 Climate Change Scenario: Focus on Dew Point Temperature Change

    Science.gov (United States)

    Okjeong, Lee; Sangdan, Kim

    2016-04-01

    According to future climate change scenarios, future temperature is expected to increase gradually. Therefore, it is necessary to reflect the effects of these climate changes to predict Probable Maximum Precipitations (PMPs). In this presentation, PMPs will be estimated with future dew point temperature change. After selecting 174 major storm events from 1981 to 2005, new PMPs will be proposed with respect to storm areas (25, 100, 225, 400, 900, 2,025, 4,900, 10,000 and 19,600 km2) and storm durations (1, 2, 4, 6, 8, 12, 18, 24, 48 and 72 hours) using the Korea hydro-meteorological method. Also, orographic transposition factor will be applied in place of the conventional terrain impact factor which has been used in previous Korean PMPs estimation reports. After estimating dew point temperature using future temperature and representative humidity information under the Korea Meteorological Administration AR5 RCP 8.5, changes in the PMPs under dew point temperature change will be investigated by comparison with present and future PMPs. This research was supported by a grant(14AWMP-B082564-01) from Advanced Water Management Research Program funded by Ministry of Land, Infrastructure and Transport of Korean government.

  14. Sources of uncertainty in relative sea-level change projections from a probabilistic point of view.

    Science.gov (United States)

    Jackson, Luke; Jevrejeva, Svetlana

    2016-04-01

    A number of relative sea-level change projections now exist in the literature that use a method of offline summation of individual components. This approach combines the projected ocean volume changes from an assimilation of ocean model outputs (e.g. CMIP5 archive) with ocean mass changes that are derived by normalising the present-day spatial fingerprint of each component (ice sheets, glaciers, land water storage) scaled by the global average projection for that component. At each stage of making the projections there are assumptions that will alter the uncertainty of the final result. For example, it is assumed that the distribution of ocean model outputs for projected dynamic sea-level change is Gaussian everywhere and the present-day pattern of ice-mass loss will continue throughout the century, neither of which is strictly the case. We quantify these sources of uncertainty to show how scenario dependency also plays a part in the projected uncertainty.

  15. CLIMATE CHANGE AND VULNERABILITY OF THE ARCTIC ELDERLY: AN ASSESSMENT FROM HUMAN RIGHTS POINT OF VIEW

    Directory of Open Access Journals (Sweden)

    Shahnaj Begum

    2012-10-01

    Full Text Available There are increasing challenges among the elderly in the Arctic region. Global warming due to climate change is one of the major reasons for these challenges. Because of climate change temperature in the region increases, which results in rapid melting of sea ice causing various environmental, social, cultural and economic problems. Population in the region suffers from these problems where elderly people are the most vulnerable. Climate change has already affected the elderly lives in different ways, such as, by physical, social, political, cultural and psychological ways. These have serious consequences in terms of human rights of this vulnerable group of people. However, the elderly people’s human rights issues have not been adequately researched in the context of this region. The goal of this paper is to present elderly related human rights issues, particularly the rights that are affected due to climate change in this specific region.

  16. Gardening Health and Safety Tips

    Science.gov (United States)

    ... Health History Parent Information Vaccines & Immunizations Healthy Living Gardening Health and Safety Tips Recommend on Facebook Tweet Share Compartir Gardening can be a great way to enjoy the ...

  17. Gas only nozzle fuel tip

    Science.gov (United States)

    Bechtel, William Theodore; Fitts, David Orus; DeLeonardo, Guy Wayne

    2002-01-01

    A diffusion flame nozzle gas tip is provided to convert a dual fuel nozzle to a gas only nozzle. The nozzle tip diverts compressor discharge air from the passage feeding the diffusion nozzle air swirl vanes to a region vacated by removal of the dual fuel components, so that the diverted compressor discharge air can flow to and through effusion holes in the end cap plate of the nozzle tip. In a preferred embodiment, the nozzle gas tip defines a cavity for receiving the compressor discharge air from a peripheral passage of the nozzle for flow through the effusion openings defined in the end cap plate.

  18. Tip gas utilisation at Elbisgraben, Basle county, Switzerland

    International Nuclear Information System (INIS)

    In summer 1992, the 5 MW high-temperature furnace of the Liestal district heating station started operation; it is fuelled with tip gas from the Elbisgraben, waste tip. The furnace has been in uninterrupted operation since then; extensive measurements have shown that the present requirements have been met in all points: Performance factor 90%, low-NOX, low-pollutant off-gas, no dioxins or furans. (orig.)

  19. Changes in Two Point Discrimination and the law of mobility in Diabetes Mellitus patients

    OpenAIRE

    Manivannan M; Periyasamy R; Narayanamurthy Vengesana

    2008-01-01

    Abstract Background Diabetic neuropathy is a family of nerve disorders with progressive loss of nerve function in 15% of diabetes mellitus (DM) subjects. Two-point discrimination (TPD) is one method of quantitatively testing for loss of nerve function. The law of mobility for TPD is known for normal subjects in earlier studies but has not been studied for diabetic subjects. This is a pilot study to evaluate and plot the law of mobility for TPD among DM subjects. Methods The Semmes Weinstein m...

  20. Implementing diversity dozens of practical tips for leading the change effort, 12 classic mistakes most organizations make and how to avoid them

    CERN Document Server

    Loden, Marilyn

    1996-01-01

    This practical and provocative guide provides the strategies and tactics used by organizations committed to implementing diversity from the top down. Focusing on the necessity for a strategic change initiative, Loden discusses: how to position diversity initiatives for maximum buy-in and support; proven strategies for managing resistance to this important change; the 12 classic mistakes made when implementing diversity initiatives - and how to avoid them.

  1. Extensive techniques of TIPS in buddi-chiari syndrome with occlusive hepatic veins

    International Nuclear Information System (INIS)

    Objective: To elaborate the ameliorative technique steps of transjugular intrahepatic portosystemic shunt (TIPS) and to evaluate its therapeutic effects to Buddi-Chiari syndrome with occlusive hepatic veins. Methods: Eleven patients were treated by the improved methods of TIPS, who were diagnosed as Buddi-Chiari syndrome with widespread stenosis or occlusive lesions of hepatic veins and verified through imagiology. Key points of the extensive techniques of TIPS were to design and build the access to the artificial hepatic vein. The changes of portal vein pressure, shunt blood flow, and stent patency posterior to the procedure were assessed and followed up for 24 months. Results: The intrahepatic shunt between portal vein and inferior vena cava was successfully built and good clinical responses were obtained in all patients. The main portal pressure decreased from (4.62 ± 0.52) kPa (x-bar ± s) to (2.16 ± 0.21) kPa posterior to the shunt. The maximum velocity of shunt blood flow was (56.2 ± 3.50) cm/s and stent patency was 7/11 at 24 months after the procedure. Conclusion: The extensive TIPS has a high successful technique rate, and is worthy of a new therapeutic means to Buddi-Chiari syndrome with occlusive hepatic veins

  2. The role of a vertical reference point in changing gait regulation in cricket run-ups.

    Science.gov (United States)

    Greenwood, Daniel; Davids, Keith; Renshaw, Ian

    2016-10-01

    The need to identify information sources which facilitate a functional coupling of perception and action in representative practice contexts is an important challenge for sport scientists and coaches. The current study investigated the role of visual information in regulating athlete gait behaviours during a locomotor pointing task in cricket. Integration of experiential knowledge of elite coaches and theoretical understanding from previous empirical research led us to investigate whether the presence of an umpire would act as a vertical informational constraint that could constrain the emergent coordination tendencies of cricket bowlers' run-up patterns. To test this idea, umpire presence was manipulated during run-ups of 10 elite medium-fast bowlers. As hypothesised, removal of the umpire from the performance environment did not result in an inability to regulate gait to intercept a target, however, the absence of this informational constraint resulted in the emergence of different movement patterns in participant run-ups. Significantly lower standard deviation values of heel-to-crease distances were observed in the umpire condition at multiple steps, compared to performance in the no-umpire condition. Manipulation of this informational constraint altered gait regulation of participants, offering a mechanism to understand how perception-action couplings can be varied during performance in locomotor pointing tasks in sport. PMID:26902778

  3. POSITIVE SOLUTIONS TO A SINGULAR nTH ORDER THREE-POINT BOUNDARY VALUE PROBLEM WITH SIGN CHANGING NONLINEARITY

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    In this paper, we consider a singular nth order three-point boundary value problem with sign changing nonlinearity. By the method of lower solution and topology degree theorem, we investigate the existence of positive solutions to the above problem. Moreover, the associated Green’s function for the above problem is also given. The results of this paper are new and extend the previous known results.

  4. FL_INTERSECTS - Transect-Shoreline Intersection Points for Florida Generated to Calculate Shoreline Change Rates

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Rates of long-term and short-term shoreline change were generated in a GIS with the Digital Shoreline Analysis System (DSAS) version 2.0, an ArcView extension...

  5. LA_INTERSECTS - Transect-Shoreline Intersection Points for Louisiana Generated to Calculate Shoreline Change Rates

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Rates of long-term and short-term shoreline change were generated in a GIS with the Digital Shoreline Analysis System (DSAS) version 2.0, an ArcView extension...

  6. Career Shifting: Starting Over in a Changing Economy. Points West Review.

    Science.gov (United States)

    Charland, William A., Jr.

    The economic shifts of the past decade represent a new era in the U.S. workplace. Many of the millions of dislocated managers and professionals will not be reemployed in similar jobs because those jobs have disappeared. The economy has changed from the pyramid shape that most people envision, with a large blue-collar base and a smaller…

  7. MS_INTERSECTS - Transect-Shoreline Intersection Points for Mississippi Generated to Calculate Shoreline Change Rates

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Rates of long-term and short-term shoreline change were generated in a GIS with the Digital Shoreline Analysis System (DSAS) version 2.0, an ArcView extension...

  8. TX_INTERSECTS - Transect-Shoreline Intersection Points for Texas Generated to Calculate Shoreline Change Rates

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Rates of long-term and short-term shoreline change were generated in a GIS with the Digital Shoreline Analysis System (DSAS) version 2.0, an ArcView extension...

  9. A new lunar absolute control point: established by images from the landing camera on Chang'e-3

    International Nuclear Information System (INIS)

    The establishment of a lunar control network is one of the core tasks in selenodesy, in which defining an absolute control point on the Moon is the most important step. However, up to now, the number of absolute control points has been very sparse. These absolute control points have mainly been lunar laser ranging retroreflectors, whose geographical location can be observed by observations on Earth and also identified in high resolution lunar satellite images. The Chang'e-3 (CE-3) probe successfully landed on the Moon, and its geographical location has been monitored by an observing station on Earth. Since its positional accuracy is expected to reach the meter level, the CE-3 landing site can become a new high precision absolute control point. We use a sequence of images taken from the landing camera, as well as satellite images taken by CE-1 and CE-2, to identify the location of the CE-3 lander. With its geographical location known, the CE-3 landing site can be established as a new absolute control point, which will effectively expand the current area of the lunar absolute control network by 22%, and can greatly facilitate future research in the field of lunar surveying and mapping, as well as selenodesy

  10. The Change of Microtubule Cytoskeleton in the Stem-Tip Cells of Sugarcane during Mitosis%甘蔗茎尖细胞有丝分裂过程中微管骨架的变化

    Institute of Scientific and Technical Information of China (English)

    李志刚; 赵洪波; 李素丽; 杨丽涛; 李杨瑞

    2008-01-01

    In order to understand the microtubule change of monoeotyls stem-tip during mitosis,the arrangement,transformation of microtubule array and its relation with chromosome movement during mitosis were studied with freezing microtome,indirect immunofluorescence,DAPI staining and fluorescence microscopy.The results showed that nueleolus was intact when the cortical miemtubules formed;cortical mierotubulos were changed into phramoplast microtubule bands at mitosis prophase.When phramoplast microtubule came into being,nuclear membrane was ruptured and chromosome was arranged at the position of cell plate;subsequently,phramoplast microtubules were changed into phragmoplast mierotubules,phramoplast mierotubules were shortening and microtubules on the sides of cell plate were increasing gradually,during this course sister chromatid was separated by microtubules at cell plate and tract to the two poles,forming phragmoplast microtubules.Then the nucleolus of two daughter cells formed and separated in the end with the increase of cells numbers.Therefore,cell division orientation could be judged from the arrangement of cell microtubules in different periods in order to understand its growth status.

  11. Chromosome tips damaged in anaphase inhibit cytokinesis.

    Directory of Open Access Journals (Sweden)

    Norman M Baker

    Full Text Available Genome maintenance is ensured by a variety of biochemical sensors and pathways that repair accumulated damage. During mitosis, the mechanisms that sense and resolve DNA damage remain elusive. Studies have demonstrated that damage accumulated on lagging chromosomes can activate the spindle assembly checkpoint. However, there is little known regarding damage to DNA after anaphase onset. In this study, we demonstrate that laser-induced damage to chromosome tips (presumptive telomeres in anaphase of Potorous tridactylis cells (PtK2 inhibits cytokinesis. In contrast, equivalent irradiation of non-telomeric chromosome regions or control irradiations in either the adjacent cytoplasm or adjacent to chromosome tips near the spindle midzone during anaphase caused no change in the eventual completion of cytokinesis. Damage to only one chromosome tip caused either complete absence of furrow formation, a prolonged delay in furrow formation, or furrow regression. When multiple chromosome tips were irradiated in the same cell, the cytokinesis defects increased, suggesting a potential dose-dependent mechanism. These results suggest a mechanism in which dysfunctional telomeres inhibit mitotic exit.

  12. Flapping propulsion with tip pitch control

    Science.gov (United States)

    Huera-Huarte, Francisco; Gharib, Morteza

    2014-11-01

    The effect of flexibility in the propulsion performance and efficiency of oscillating pitching foils has received a large amount of attention in the past years. Scientists have used simplified robotic models that mimic the kinematics of flying and swimming animals, in order to get inspiration to build more efficient engineering systems. Compliance is one of the aspects that has received more attention, as it seems to be a common feature in nature's flyers and swimmers. Active or passive control elements are also common in nature. We will show how thrust generation in a pitching fin, can be greatly affected by controlling the tip pitch motion dynamically and independently of the fin itself. This is in fact a controlled local change of curvature of the end of the fin. A robotic system has been designed in a way that not only flapping amplitudes and frequencies can be controlled, but also the amplitudes and frequencies of the tip and the phase difference between the tip and the fin. We measured thrust forces and the vortex dynamics in the near wake of the system, by using planar DPIV (Digital Particle Image Velocimetry) in a wide variety of flapping situations with tip control. Funding from Spanish Ministry of Science through Grant DPI2012-37904 is gratefully acknowledged.

  13. PowerPoint 2010 Bible

    CERN Document Server

    Wempen, Faithe

    2010-01-01

    Master PowerPoint and improve your presentation skills-with one book!. It's no longer enough to have slide after slide of text, bullets, and charts. It's not even enough to have good speaking skills if your PowerPoint slides bore your audience. Get the very most out of all that PowerPoint 2010 has to offer while also learning priceless tips and techniques for making good presentations in this new PowerPoint 2010 Bible. Well-known PowerPoint expert and author Faithe Wempen provides formatting tips; shows you how to work with drawings, tables, and SmartArt; introduces new collaboration tools; wa

  14. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

    Medline Plus

    Full Text Available ... What are the limitations of TIPS? What is a Transjugular Intrahepatic Portosystemic Shunt (TIPS)? A transjugular intrahepatic ... encourage linking to this site. × Recommend RadiologyInfo to a friend Send to (friend's e-mail address): From ( ...

  15. Early change in proteinuria as a surrogate end point for kidney disease progression

    DEFF Research Database (Denmark)

    Inker, Lesley A; Levey, Andrew S; Pandya, Kruti;

    2014-01-01

    . Pooled estimates for the proportion of treatment effect on the clinical outcome explained by early decline in proteinuria ranged from -7.0% (95%CI, -40.6% to 26.7%) to 43.9% (95%CI, 25.3% to 62.6%) across 5 intervention types. The direction of the pooled treatment effects on early change in proteinuria...... intervention types. SELECTION CRITERIA FOR STUDIES: Randomized controlled trials of kidney disease progression until 2007 with measurements of proteinuria both at baseline and during the first year of follow-up, with at least 1 further year of follow-up for the clinical outcome. PREDICTOR: Early change in...... proteinuria. OUTCOMES: Doubling of serum creatinine level, end-stage renal disease, or death. RESULTS: Early decline in proteinuria was associated with lower risk of the clinical outcome (pooled HR, 0.74 per 50% reduction in proteinuria); this association was stronger at higher levels of baseline proteinuria...

  16. Empirical likelihood based detection procedure for change point in mean residual life functions under random censorship.

    Science.gov (United States)

    Chen, Ying-Ju; Ning, Wei; Gupta, Arjun K

    2016-05-01

    The mean residual life (MRL) function is one of the basic parameters of interest in survival analysis that describes the expected remaining time of an individual after a certain age. The study of changes in the MRL function is practical and interesting because it may help us to identify some factors such as age and gender that may influence the remaining lifetimes of patients after receiving a certain surgery. In this paper, we propose a detection procedure based on the empirical likelihood for the changes in MRL functions with right censored data. Two real examples are also given: Veterans' administration lung cancer study and Stanford heart transplant to illustrate the detecting procedure. Copyright © 2016 John Wiley & Sons, Ltd. PMID:26936529

  17. Empirical likelihood based detection procedure for change point in mean residual life functions under random censorship.

    Science.gov (United States)

    Chen, Ying-Ju; Ning, Wei; Gupta, Arjun K

    2016-05-01

    The mean residual life (MRL) function is one of the basic parameters of interest in survival analysis that describes the expected remaining time of an individual after a certain age. The study of changes in the MRL function is practical and interesting because it may help us to identify some factors such as age and gender that may influence the remaining lifetimes of patients after receiving a certain surgery. In this paper, we propose a detection procedure based on the empirical likelihood for the changes in MRL functions with right censored data. Two real examples are also given: Veterans' administration lung cancer study and Stanford heart transplant to illustrate the detecting procedure. Copyright © 2016 John Wiley & Sons, Ltd.

  18. From PowerPoints to Reality - Managing Strategic Change in the Paper Packaging Industry

    OpenAIRE

    Olander Roese, Malin

    2014-01-01

    This thesis explores and describes strategic change towards increased customer orientation and innovation in the Swedish forest and paper packaging industry, an industry which has been subject to calls for new strategic directions for more than two decades. The large-scale and cost-efficient strategy, which has been the industry's hallmark, is in need of a more customer based and innovative emphasis. The research is inspired by different schools of thought in strategy and m...

  19. Detecting long-term changes in point-source fossil CO2 emissions with tree ring archives

    Science.gov (United States)

    Keller, Elizabeth D.; Turnbull, Jocelyn C.; Norris, Margaret W.

    2016-05-01

    We examine the utility of tree ring 14C archives for detecting long-term changes in fossil CO2 emissions from a point source. Trees assimilate carbon from the atmosphere during photosynthesis, in the process faithfully recording the average atmospheric 14C content in each new annual tree ring. Using 14C as a proxy for fossil CO2, we examine interannual variability over six years of fossil CO2 observations between 2004-2005 and 2011-2012 from two trees growing near the Kapuni Gas Treatment Plant in rural Taranaki, New Zealand. We quantify the amount of variability that can be attributed to transport and meteorology by simulating constant point-source fossil CO2 emissions over the observation period with the atmospheric transport model WindTrax. We compare model simulation results to observations and calculate the amount of change in emissions that we can detect with new observations over annual or multi-year time periods, given both the measurement uncertainty of 1ppm and the modelled variation in transport. In particular, we ask, what is the minimum amount of change in emissions that we can detect using this method, given a reference period of six years? We find that changes of 42 % or more could be detected in a new sample from one year at the same observation location or 22 % in the case of four years of new samples. This threshold is reduced and the method becomes more practical the more the size of the signal increases. For point sources 10 times larger than the Kapuni plant (a more typical size for power plants worldwide), it would be possible to detect sustained emissions changes on the order of 10 %, given suitable meteorology and observations.

  20. Prediction of change in protein unfolding rates upon point mutations in two state proteins.

    Science.gov (United States)

    Chaudhary, Priyashree; Naganathan, Athi N; Gromiha, M Michael

    2016-09-01

    Studies on protein unfolding rates are limited and challenging due to the complexity of unfolding mechanism and the larger dynamic range of the experimental data. Though attempts have been made to predict unfolding rates using protein sequence-structure information there is no available method for predicting the unfolding rates of proteins upon specific point mutations. In this work, we have systematically analyzed a set of 790 single mutants and developed a robust method for predicting protein unfolding rates upon mutations (Δlnku) in two-state proteins by combining amino acid properties and knowledge-based classification of mutants with multiple linear regression technique. We obtain a mean absolute error (MAE) of 0.79/s and a Pearson correlation coefficient (PCC) of 0.71 between predicted unfolding rates and experimental observations using jack-knife test. We have developed a web server for predicting protein unfolding rates upon mutation and it is freely available at https://www.iitm.ac.in/bioinfo/proteinunfolding/unfoldingrace.html. Prominent features that determine unfolding kinetics as well as plausible reasons for the observed outliers are also discussed. PMID:27264959

  1. The fitness effects of a point mutation in Escherichia coli change with founding population density.

    Science.gov (United States)

    Cao, Huansheng; Plague, Gordon R

    2016-08-01

    Although intraspecific competition plays a seminal role in organismal evolution, little is known about the fitness effects of mutations at different population densities. We identified a point mutation in the cyclic AMP receptor protein (CRP) gene in Escherichia coli that confers significantly higher fitness than the wildtype at low founding population density, but significantly lower fitness at high founding density. Because CRP is a transcription factor that regulates the expression of nearly 500 genes, we compared global gene expression profiles of the mutant and wildtype strains. This mutation (S63F) does not affect expression of crp itself, but it does significantly affect expression of 170 and 157 genes at high and low founding density, respectively. Interestingly, acid resistance genes, some of which are known to exhibit density-dependent effects in E. coli, were consistently differentially expressed at high but not low density. As such, these genes may play a key role in reducing the crp mutant's fitness at high density, although other differentially expressed genes almost certainly also contribute to the fluctuating fitness differences we observed. Whatever the causes, we suspect that many mutations may exhibit density-dependent fitness effects in natural populations, so the fate of new mutations may frequently depend on the effective population size when they originate. PMID:27344657

  2. The fitness effects of a point mutation in Escherichia coli change with founding population density.

    Science.gov (United States)

    Cao, Huansheng; Plague, Gordon R

    2016-08-01

    Although intraspecific competition plays a seminal role in organismal evolution, little is known about the fitness effects of mutations at different population densities. We identified a point mutation in the cyclic AMP receptor protein (CRP) gene in Escherichia coli that confers significantly higher fitness than the wildtype at low founding population density, but significantly lower fitness at high founding density. Because CRP is a transcription factor that regulates the expression of nearly 500 genes, we compared global gene expression profiles of the mutant and wildtype strains. This mutation (S63F) does not affect expression of crp itself, but it does significantly affect expression of 170 and 157 genes at high and low founding density, respectively. Interestingly, acid resistance genes, some of which are known to exhibit density-dependent effects in E. coli, were consistently differentially expressed at high but not low density. As such, these genes may play a key role in reducing the crp mutant's fitness at high density, although other differentially expressed genes almost certainly also contribute to the fluctuating fitness differences we observed. Whatever the causes, we suspect that many mutations may exhibit density-dependent fitness effects in natural populations, so the fate of new mutations may frequently depend on the effective population size when they originate.

  3. Key points on temperature change of the past 2000 years in China

    Institute of Scientific and Technical Information of China (English)

    GE Quansheng; ZHENG Jingyun; MAN Zhimin; FANG Xiuqi; ZHANG Piyuan

    2004-01-01

    Temperature change of the past 2000 years in China is discussed based on the winter half-year temperature series of the past 2000 years in eastern China reconstructed recently, and other related studies. The main conclusions are as follows: (1) The Little Ice Age (LIA) in China began in the early of the 14th century (1320s) and ended in the beginning of the 20th century (1910s), which was composed of four evident cold stages and three short warming stages. The cold period in the Wei, Jin and South-North dynasties (210s~560s) was the only one comparable with LIA for the past 2000 years. (2) The Medieval Warm Period (MWP) in China began in the 930s and ended in the 1310s, which was composed of two warm stages over 100 years and a cold stage less than 100 years. (3) The climate in the Sui and Tang dynasties should be divided into two stages: the climate in the 570s~770s was as warm as that in the 20th century; while the temperature in the 780s~920s was lower than that in the 1950s~1970s. (4) In eastern China as a whole, winter half-year temperature variation with over 1 ℃ occurred between the cold and warm stages on centennial scale, while the changing rate exceeded 1.0 ℃ per century. (5) There exists an about 1350-year periodicity in the historical temperature change. Inferred from the periodicity, the most likely historical analogue for the warming in the 20th century is the warm stage of the Sui and Tang dynasties (570s~770s), instead of the Medieval Warm Period. (6) Although it was critically warm, the temperature of the 20th century in eastern China is still within the threshold of the variability of the last 2000 years.

  4. Japan's Educational System. A Few Main Points and Recent Changes in the Educational System

    OpenAIRE

    Bertha Gunnarsdóttir 1993

    2016-01-01

    Any educational system has its advantages and disadvantages; the Japanese system is one that aims for equality between its students. However this thesis will look at whether or not these statements are true, and see where the system is fair compared to where it is not. Japanese education and efficiency has become more known in the last few decades. This essay aims to look at the Japanese educational system and it’s more recent changes. It will look at the educational reforms and see the ca...

  5. Dynamic Changes, Cut-Off Points, Sensitivity, and Specificity of Laboratory Data to Differentiate Macrophage Activation Syndrome from Active Disease

    Directory of Open Access Journals (Sweden)

    Raheleh Assari

    2015-01-01

    Full Text Available Purpose. To compare the laboratory data and changes in these data between patients with MAS and patients with flare-up of the autoimmune diseases. Methods. In a prospective study, the static laboratory data and dynamic changes in the selected data in 17 consecutive patients with MAS and 53 patients with active disease of SJIA, PJIA, Kawasaki disease, and SLE were compared. The ROC curve analysis was used to evaluate cut-off points, sensitivity, and specificity of the static and dynamic laboratory data to differentiate between MAS and active disease. Results. In the MAS group, the mean CRP3, ALT, AST, total bilirubin, ferritin, LDH, PT, PTT, and INR were significantly higher and the mean WBC2, PMN2, Lymph2, Hgb1, 2, 3, ESR2, serum albumin, and sodium were significantly lower than in control group. Some of the important cut-off points were PLT2 38.5, ALT > 38, WBC 5277 ng/mL. Conclusion. The dynamic changes in some laboratory data, especially PLT, can differentiate between MAS and active disease. The changes in WBC, PMN, and ESR and the levels of the liver enzymes may also be helpful in the early differentiation. Very high levels of ferritin may also help the diagnosis along with other clinical and laboratory signs.

  6. Transjugular Intrahepatic Portosystemic Shunt (TIPS): Current Status and Future Possibilities

    International Nuclear Information System (INIS)

    Since the insertion of the first TIPS in 1989 much has been learned about this therapeutic procedure. It has an established role for the treatment of some complications of portal hypertension: prevention of recurrent variceal bleeding and rescue of patients with acute uncontrollable variceal bleeding. In addition TIPS is useful for Budd-Chiari syndrome, refractory ascites and hepatorenal syndrome, although its specific role in these indications remains to be definitively established. However, the decrease in sinusoidal blood flow induced by TIPS can lead to the patient developing hepatic encephalopathy and liver failure in some cases. Therefore, TIPS should be used with caution in patients with very poor liver function. From a technical point of view, successful placement of TIPS is achieved in more than 98% of cases by experienced groups. At present, evaluation of TIPS dysfunction based on morphology probably leads to an overdiagnosis of this complication since most of these cases are not associated with clinical manifestations (recurrent bleeding or refractory ascites). The major disadvantage of TIPS remains its poor long-term patency requiring a mandatory surveillance program. The indicator for shunt function/malfunction should be the portosystemic pressure gradient, which is best assessed by intravascular measurements. Shunt obstructions may be prevented or reduced by the use of stent-grafts in the future

  7. Infection in the Nasal Tip Caused by Acellular Dermal Matrix.

    Science.gov (United States)

    Lee, Kun Hee

    2015-12-01

    A 19-year-old female patient visited our clinic for rhinoplasty. She complained about her low take-off point, which was apparent in profile view, and wanted slight tip projection. She refused additional cartilage harvesting from ears or ribs but consented to the use of homologous tissue, including acellular dermal matrix, for her dorsum and tip. Septoturbinoplasty was performed, and only a very small amount of septal cartilage could be harvested. It was used as both the columellar strut and the alar rim graft. Nasal dorsum and tip were augmented with acellular dermal matrix. Three months postoperatively, she experienced a few episodes of edema and redness on her nasal tip, followed by pus exudation from the nasal skin. Six months postoperatively, she underwent revision rhinoplasty for removal of inflamed grafts, and onlay tip graft with homologous rib cartilage was performed. Nasal dorsum or tip grafts are an integral part of Asian rhinoplasty. Autogenous tissue is the gold standard for grafting materials. However, the limited availability of autogenous tissue and the preference of patients and surgeons for artificial surgical implants make Asian rhinoplasty challenging. Unavailability of autogenous cartilage and patient refusal of artificial implants led to the use of acellular dermal matrix (ADM) in the nasal dorsum and tip for this case. This is the first report of postoperative complication because of infection rather than absorption after ADM use. PMID:26894006

  8. Changes in Two Point Discrimination and the law of mobility in Diabetes Mellitus patients

    Directory of Open Access Journals (Sweden)

    Manivannan M

    2008-01-01

    Full Text Available Abstract Background Diabetic neuropathy is a family of nerve disorders with progressive loss of nerve function in 15% of diabetes mellitus (DM subjects. Two-point discrimination (TPD is one method of quantitatively testing for loss of nerve function. The law of mobility for TPD is known for normal subjects in earlier studies but has not been studied for diabetic subjects. This is a pilot study to evaluate and plot the law of mobility for TPD among DM subjects. Methods The Semmes Weinstein monofilament (SWMF was used to measure the loss of protective sensation. An Aesthesiometer was used to find the TPD of several areas in upper and lower extremities for normal and diabetic subjects. All the subjects were screened for peripheral artery occlusive disease with ankle brachial pressure index (0.9 or above. Results TPD of normal and diabetic subjects for different areas of hands and legs from proximal to distal is evaluated for 18 subjects. TPD values decrease from proximal to distal areas. Vierodt's law of mobility for TPD holds good for normal subjects in the hand and foot areas. The law of mobility for TPD in DM subjects holds well in the hand but doesn't hold well in foot areas with or without sensation. Conclusion TPD is a quantitative and direct measure of sensory loss. The TPD value of diabetic subjects reveals that the law of mobility do not hold well for Diabetic subjects in foot areas. The significance of this result is that the TPD of the diabetic subjects could provide direct, cost effective and quantitative measure of neuropathy.

  9. Trend analysis and change point detection of annual and seasonal precipitation and temperature series over southwest Iran

    Indian Academy of Sciences (India)

    Mohammad Zarenistanak; Amit G Dhorde; R H Kripalani

    2014-03-01

    This paper presents results of trend analysis and change point detection of annual and seasonal precipitation, and mean temperature (TM), maximum temperature (TMAX) and minimum temperature (TMIN) time series of the period 1950–2007. Investigations were carried out for 50 precipitation stations and 39 temperature stations located in southwest Iran. Three statistical tests including Pettitt’s test, Sequential Mann–Kendall test (SQ-MK test) and Mann–Kendall rank test (MK-test) were used for the analysis. The results obtained for precipitation series indicated that most stations showed insignificant trends in annual and seasonal series. Out of the stations which showed significant trends, highest numbers were observed during winter season while no significant trends were detected in summer precipitation. Moreover, no decreasing significant trends were detected by statistical tests in annual and seasonal precipitation series. The analysis of temperature trends revealed a significant increase during summer and spring seasons. TMAX was more stable than TMIN and TM, and winter was stable compared to summer, spring and autumn seasons. The results of change point detection indicated that most of the positive significant mutation points in TM, TMAX and TMIN began in the 1990s.

  10. Tipping the scales.

    Science.gov (United States)

    1998-12-01

    In the US, the October 1998 murder of a physician who performed abortions was an outward manifestation of the insidious battle against legal abortion being waged by radical Christian social conservatives seeking to transform the US democracy into a theocracy. This movement has been documented in a publication entitled, "Tipping the Scales: The Christian Right's Legal Crusade Against Choice" produced as a result of a 4-year investigation conducted by The Center for Reproductive Law and Policy. This publication describes how these fundamentalists have used sophisticated legal, lobbying, and communication strategies to further their goals of challenging the separation of church and state, opposing family planning and sexuality education that is not based solely on abstinence, promoting school prayer, and restricting homosexual rights. The movement has resulted in the introduction of more than 300 anti-abortion bills in states, 50 of which have passed in 23 states. Most Christian fundamentalist groups provide free legal representation to abortion clinic terrorists, and some groups solicit women to bring specious malpractice claims against providers. Sophisticated legal tactics are used by these groups to remove the taint of extremism and mask the danger posed to US constitutional principles being posed by "a well-financed and zealous brand of radical lawyers and their supporters." PMID:12294553

  11. Tips to Manage Anxiety and Stress

    Science.gov (United States)

    ... Resources Awards Consumers Tips to Manage Anxiety and Stress Main navigation Tips Severe Storms: How to Reduce ... and many more. Fitness Tips: Stay Healthy, Manage Stress For the biggest benefits of exercise, try to ...

  12. Tip-Clearance Vortex Characterized With Three-Dimensional Digital Particle Image Velocimetry

    Science.gov (United States)

    John, W. Trevor

    2002-01-01

    An optical measurement technique known as Three-Dimensional Digital Particle Image Velocimetry (3-D DPIV) was used to characterize the tip clearance flow in NASA Glenn Research Center's low-speed axial compressor. 3-D DPIV is a technique in which a stereoscopic imaging system consisting of two cross-correlation cameras is used to record particles entrained in a flow as a laser light sheet is pulsed at two instances in time. Although 3-D DPIV has been used elsewhere, this is the first time it has been used to measure compressor tip clearance flows. In-house modifications of the DPIV system include the use of effective seeding technology and a novel system to perform a priori calibrations at all five measurement planes, greatly reducing facility run time. Computational fluid dynamics predictions, which are used to guide design changes toward improving the efficiency and operating range of turbomachinery, can be verified and improved by comparison with 3-D DPIV measurements of the actual tip clearance flow. This measurement campaign dealt with the characterization of the tip clearance vortex in the first stage of a four-stage axial compressor. The tip clearance vortex is formed in compressors operating with a clearance gap between the moving rotor blade tips and the stationary casing when a leakage flow, forced from the pressure side of the blade over the blade tip, forms a vortical structure on the suction side of the blade. 3-D DPIV is ideally suited to measure the clearance vortex for two reasons: (1) this technique captures the entire blade passage flow at one instant in time, so that wandering of the vortex during the measurement does not smear out velocity gradients in the flow field, and (2) the spanwise component of velocity changes sign across the vortex core, providing a more accurate measurement of the vortex location than was available with previous two-dimensional measurement approaches. These two attributes of the data will enable computational fluid

  13. Thermal writing using a heated atomic force microscope tip

    Science.gov (United States)

    Mamin, H. J.

    1996-07-01

    Resistive heating of an atomic force microscope tip was used to perform thermally induced surface modifications. Heating was achieved by dissipating power in the legs of an electrically conducting silicon cantilever. Temperatures of up to 170 °C were obtained using 40 mW of input power. Electrical measurements used to monitor the temperature showed thermal time constants of 0.35-0.45 ms, depending on whether the tip was in contact with a substrate. The heated tip was used to demonstrate thermomechanical writing on a polycarbonate substrate, as well as thermal writing of an optical phase change material.

  14. INFLUENCE OF LOCAL INFILITRATION ANESTHESIA OF SCALP-POINT ON ACUPUNCTURE INDUCED CHANGES OF CEREBRAL BLOOD PERFUSION DETECTED BY SPECT

    Institute of Scientific and Technical Information of China (English)

    郭长春; 王凡; 贾少微

    2003-01-01

    Objective: To observe the influence of local infiltration anesthesia at the scalp-point on acupuncture stimulation induced changes of cerebral blood perfusion in the brain. Methods: Experiments were conducted in 10 healthy volunteer subjects (8 males and 2 females) who were ordered to take a lying position on a specific bed with their heads keeping in a fixed position. Scalp-point used was Motor Area (MS 6). The first syringe needle (gauge-5) was inserted into the scalp from the upper 1/5 of MS-6 and the second syringe needle inserted into the scalp from the middle 2/5 of MS-6 and advanced downward, with the two needles connected to a HAN's Therapeutic Apparatus. Images of the brain were then taken before and after electroacupuncture (EA) stimulation, and after local injection of 1% lidocaine [mixed with epinephrine (1∶200,000, 3 mL)] plus EA by using Siemens ECAM/ICON Single Photo Emission Computed Tomography (SPECT). Intravenous injection of Ethyl cysteinate dimmer 555 MBq was performed before displaying cerebral images. Data of blood functional changing rat (BFCR%) were analyzed quantitatively using a mathematic model. Results: Before EA stimulation, the blood perfusion and function of cerebral cortex, thalamus, basal ganglion and cerebellum on both sides of the brain were basically symmetry. Following EA of MS-6, BFCR% of the contralateral thalamus, parietal lobe and the frontal lobe increased significantly. Following local infiltration anesthesia, BFCR% of the contralatral thalamus declined markedly (P<0.05). The results of quantitative analysis were in agreement with those of visual observation. Conclusion: Local infiltration anesthesia of the scalp-point can significantly weaken or block EA stimulation induced changes of BFCR%.

  15. Aerodynamic and heat transfer aspects of tip and casing treatments used for turbine tip leakage control

    Science.gov (United States)

    Gumusel, Baris

    Axial flow turbine stages are usually designed with a gap between the tips of the rotating blades and a stationary outer casing. The presence of a strong pressure gradient across this gap drives flow from the pressure side of the blade to the suction side. This leakage flow creates a significant amount of energy loss of working fluid in the turbine stage. In a modern gas turbine engine the outer casing of the high-pressure turbine is also exposed to a combination of high flow temperatures and heat transfer coefficients. The casing is consequently subjected to high levels of convective heat transfer, a situation that is aggravated by flow unsteadiness caused by periodic blade-passing events. An experimental investigation of the aerodynamic and heat transfer effect of tip and casing treatments used in turbine tip leakage control was conducted in a large scale, low speed, rotating research turbine facility. The effects of casing treatments were investigated by measuring the total pressure field at the exit of the rotor using a high frequency response total pressure probe. A smooth wall as a baseline case was also investigated. The test cases presented include results of casing treatments with varying dimensions for tip gap height of t/h=2.5%. The results of the rotor exit total pressure indicate that the casing treatment significantly reduced the leakage mass flow rate and the momentum deficit in the core of the tip vortex. The reductions obtained in the tip vortex size and strength influenced the tip-side passage vortex and other typical core flow characteristics in the passage. Casing treatments with the highest ridge height was the most effective in reducing the total pressure loss in the leakage flow of the test blades. This was observed at a radius near the core of the tip vortex. It appears that casing treatments with the highest ridge height is also the most effective from a global point of view, as shown by the passage averaged pressure coefficient obtained in

  16. Effects of tip-pruning treatment on source-sink regulation of Catharanthus roseus seedlings

    Institute of Scientific and Technical Information of China (English)

    GAO Yang; ZHANG Xue-ke; GUO Xiao-rui; SUN Yan-fei; ZU Yuang-gang

    2006-01-01

    Fifty cultivated Catharanthus roseus seedlings were selected for tip-pruning treatment and the effects of tip-pruning on seedling growth and source-sink regulation were investigated for revealing physiological mechanisms of plants. The results showed that tip-pruning treatment resulted in obvious inhibition of apical dominance and enhancement of branching numbers. The contents of soluble sugars, acid sucrose invertase activity (AI) had a great change in differently positional leaves of the seedling. The sink strength in tip leaves of seedlings dramatically declined after tip-pruning treatment, while that in the leaves at the middle and bottom of seedlings had no obvious changes. The inhibition of apical dominance of tip leaves of seedlings was caused by the diminished sink strength due to tip-pruning treatment,

  17. Tipping time of a quantum rod

    Energy Technology Data Exchange (ETDEWEB)

    Parrikar, Onkar [Birla Institute of Technology and Science-Pilani, Goa campus, Zuarinagar, Goa 4032726 (India)], E-mail: onkarsp@gmail.com

    2010-03-15

    The behaviour of a quantum rod, pivoted at its lower end on an impenetrable floor and restricted to moving in the vertical plane under the gravitational potential, is studied analytically under the approximation that the rod is initially localized to a 'small-enough' neighbourhood around the point of classical unstable equilibrium. It is shown that the rod evolves out of this neighbourhood. The time required for this to happen, i.e. the tipping time, is calculated using the semi-classical path integral. It is shown that equilibrium is recovered in the classical limit, and that our calculations are consistent with the uncertainty principle.

  18. Educating generation X and generation Y: teaching tips for librarians.

    Science.gov (United States)

    Kipnis, Daniel G; Childs, Gary M

    2004-01-01

    This article provides a list of helpful teaching tips for instructional librarians who need to meet the changing generational needs of their patrons. Specific generational qualities and attitudes of Generation X and Generation Y are discussed along with educational techniques and software recommendations. These tips are based on the authors' experiences at Drexel University's Hahnemann Library and Thomas Jefferson University's Scott Memorial Library, both of which are academic health sciences libraries.

  19. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

    Medline Plus

    Full Text Available ... anti-inflammatory drugs (NSAIDs) or blood thinners several days prior to your procedure and instructed to not ... overnight at the hospital for one or more days. What is Transjugular Intrahepatic Portosystemic Shunt (TIPS)? What ...

  20. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

    Medline Plus

    Full Text Available ... blood draining from the bowel back to the heart while avoiding the liver. TIPS may successfully reduce ... blood away from the liver back to the heart). A stent is then placed in this tunnel ...

  1. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

    Medline Plus

    Full Text Available ... look like? In this procedure, x-ray or ultrasound equipment, a stent, and a balloon-tipped catheter ... over a table on which the patient lies. Ultrasound scanners consist of a console containing a computer ...

  2. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

    Medline Plus

    Full Text Available ... Patients who typically need a TIPS have portal hypertension , meaning they have increased pressure in the portal ... leading to cirrhosis (scarring of the liver). Portal hypertension can also occur in children, although children are ...

  3. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

    Medline Plus

    Full Text Available ... bear denotes child-specific content. Related Articles and Media Radiation Dose in X-Ray and CT Exams Contrast Materials Venography Images related to Transjugular Intrahepatic Portosystemic Shunt (TIPS) About ...

  4. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

    Medline Plus

    Full Text Available ... in creating the TIPS. top of page Additional Information and Resources Society of Interventional Radiology (SIR) - Patient ... Send us your feedback Did you find the information you were looking for? Yes No To submit ...

  5. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

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    Full Text Available ... top of page What are the benefits vs. risks? Benefits A TIPS is designed to produce the ... skin that does not have to be stitched. Risks Any procedure where the skin is penetrated carries ...

  6. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

    Medline Plus

    Full Text Available ... the current generation of GORE-TEX-lined stents Serious complications, reported in fewer than five percent of ... limitations of TIPS? Patients with more advanced liver disease are at greater risk for worsening liver failure ...

  7. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

    Medline Plus

    Full Text Available ... pressure. top of page How does the procedure work? A TIPS reroutes blood flow in the liver ... of bleeding that can occur can sometimes be life threatening and those patients are monitored in intensive ...

  8. Tips for Socializing with Aphasia

    Science.gov (United States)

    ... After Stroke Weight Training After Stroke Tips for Improving Fine Motor Skills Functional Tone Management Arm Training Program Constraint-Induced Movement Therapy Emotional & Behavioral Challenges Self-Esteem after Stroke Post-Stroke Mood Disorders One-side ...

  9. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

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    Full Text Available ... you are pregnant and discuss any recent illnesses, medical conditions, allergies and medications you’re taking. You ... with ascites or variceal bleeding resistant to traditional medical treatments. The greatest difference in performing TIPS in ...

  10. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

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    Full Text Available ... is completed. top of page What are the benefits vs. risks? Benefits A TIPS is designed to produce the same ... the possible charges you will incur. Web page review process: This Web page is reviewed regularly by ...

  11. Dining Out Tips by Cuisine

    Science.gov (United States)

    ... Food and Beverage Toolkit Dining Out Tips by Cuisine Updated:Aug 9,2016 You can eat out ... Cajun Chinese Family Restaurants Fast Food French Greek Indian Italian Japanese Mexican Steakhouses Thai Vegetarian Vietnamese Don’ ...

  12. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

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    Full Text Available ... system. This pressure buildup can cause blood to flow backward from the liver into the veins of ... does the procedure work? A TIPS reroutes blood flow in the liver and reduces abnormally high blood ...

  13. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

    Medline Plus

    Full Text Available ... TIPS may successfully reduce internal bleeding in the stomach and esophagus in patients with cirrhosis. Tell your ... the liver into the veins of the spleen, stomach, lower esophagus, and intestines, causing enlarged vessels, bleeding ...

  14. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

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    Full Text Available ... local anesthetic medications, general anesthesia or to contrast materials containing iodine (sometimes referred to as "dye" or " ... the placement of the TIPS stent, a contrast material will be injected in the hepatic vein to ...

  15. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

    Medline Plus

    Full Text Available ... of page How should I prepare? You should report to your doctor all medications that you are ... with ascites or variceal bleeding resistant to traditional medical treatments. The greatest difference in performing TIPS in ...

  16. Probing the probe: AFM tip-profiling via nanotemplates to determine Hamaker constants from phase-distance curves

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez, Raul D. [Institute of Physics, Chemnitz University of Technology, D-09107 Chemnitz (Germany); Lacaze, Emmanuelle, E-mail: emmanuelle.lacaze@insp.jussieu.fr [CNRS, UMR7588, Institut des Nano-Sciences de Paris (INSP), 4 place Jussieu, F-75005 Paris (France); UPMC Univ Paris 06, UMR 7588, Institut des Nano-Sciences de Paris (INSP), 4 Place Jussieu, F-75005 Paris (France); Jupille, Jacques [CNRS, UMR7588, Institut des Nano-Sciences de Paris (INSP), 4 place Jussieu, F-75005 Paris (France); UPMC Univ Paris 06, UMR 7588, Institut des Nano-Sciences de Paris (INSP), 4 Place Jussieu, F-75005 Paris (France)

    2012-10-15

    A method to determine the van der Waals forces from phase-distance curves recorded by atomic force microscopy (AFM) in tapping mode is presented. The relationship between the phase shift and the tip-sample distance is expressed as a function of the product of the Hamaker constant by tip radius. Silica-covered silicon tips are used to probe silica-covered silicon substrate in dry conditions to avoid capillary effects. Tips being assumed spherical, radii are determined in situ by averaging profiles recorded in different directions on hematite nanocrystals acting as nanotemplates, thus accounting for tip anisotropy. Through a series of reproducible measurements performed with tips of various radii (including the in-situ characterization of a damaged tip), a value of (6.3{+-}0.4) Multiplication-Sign 10{sup -20} J is found for the Hamaker constant of interacting silica surfaces in air, in good agreement with tabulated data. The results demonstrate that the onset of the tip-surface interaction is dominated by the van der Waals forces and that the total force can be modeled in the framework of the harmonic approximation. Based on the tip radius and the Hamaker constant associated to the tip-substrate system, the model is quite flexible. Once the Hamaker constant is known, a direct estimate of the tip size can be achieved whereas when the tip size is known, a quantitative evaluation of the van der Waals force becomes possible on different substrates with a spatial resolution at the nanoscale. -- Highlights: Black-Right-Pointing-Pointer Van der Waal forces in tapping mode atomic force microscopy. Black-Right-Pointing-Pointer Harmonic approximation model of phase-distance curves probed by simulations. Black-Right-Pointing-Pointer Silica tips and surfaces as a model case. Black-Right-Pointing-Pointer Tip geometry determined in situ by nanoparticles as nanotemplates. Black-Right-Pointing-Pointer Method to derive the Hamaker constant for any tip/surface system.

  17. Effect of Permeability of Tipping Paper on Cigarette Burning Temperature and the Property of Mainstream Smoke

    Science.gov (United States)

    Yao, Zhen-Yu; Shen, Yan; Huang, Hai-Qun; Xu, Ji-Cang

    2016-05-01

    Cigarette smoke analysis of tipping paper with different permeability was carried out. The infrared thermal imager was used to measure burning temperature of cigarette with different permeability tipping paper. The results indicated that with the increase of tipping paper permeability, Tar, CO and nicotine in cigarette mainstream were significantly linear decreased, puff count was increased. Tipping paper permeability had a great influence on cigarette burning temperature. With the increase of tipping paper permeability, the third puff burning temperature and the average peak temperature values were dropped obviously, but the changes of smoldering temperature were not obvious. In addition, smoldering average temperature was significantly lower than the third puff burning temperature and peak temperature.

  18. Single layer and multilayer tip coatings in magnetic force microscopy

    Science.gov (United States)

    Casey, S. M.; Lord, D. G.; Grundy, P. J.; Slade, M.; Lambrick, D.

    1999-04-01

    Interactions between the imaging tip and the sample in magnetic force microscopy (MFM) have been investigated by studying the magnetic microstructure of a range of epitaxial garnet films. Etched silicon cantilever probes, coated with CoPt alloy films and Co/Pt multilayers, provided a range of MFM probes for this study. Resonant torque magnetometry was used to characterize their magnetic properties. Phase change images were found to vary considerably in terms of relative "domain volumes" at the surface depending on which probe was used. Decreasing the moment of the alloy coated tips by using thinner layers reduces the "magnetizing" interaction of the tip field but also reduced the signal to noise ratio. By coating the tip with a multilayer a good signal to noise ratio could be obtained with very little interaction. Force-distance curves were used to study the response of the tips at various lift heights. The tips coated with alloy films gave a significant decrease in signal to noise ratio as the lift height increased whereas the multilayer tips maintained a signal which varied little with lift height.

  19. The Effectiveness of Modified Vertical Dome Division Technique in Reducing Nasal Tip Projection in Rhinoplasty

    Directory of Open Access Journals (Sweden)

    Mohammad Rafatbakhs

    2011-09-01

    Full Text Available Background: The technique of vertical dome division or tip defining, involves incising the lateral crura and vestibular skin at or lateral to the dome or tip defining point. The incision divides the lower lateral cartilage into a lateral segment and a medial segment, which are advanced anteriorly and sutured together to increase tip projection. The present study aimed at assessing a new vertical dome division, which is a modified version of vertical dome technique to decrease nasal tip projection, and increase or decrease nasal tip rotation and other tip deformities. Methods: The medical files of patients undergone rhinoplasty from 2003 to 2008 were retrospectively analyzed. The files were selected from a computerized rhinoplasty database of patients, who had been operated using a modified vertical dome technique and followed-up for one year or more after the surgery. Results: A total of 3756 patients were operated. Complications related to the nasal tip such as bossae, bifidity, persistent tip projection or tip asymmetry was seen in 81 patients (2.1%. Revisions for tip-related problems were performed in 42 patients (1.1%. Conclusions: The findings suggest that the modified vertical dome technique is an effective method for nasal tip deprojection and narrowing via an open approach. The length of follow-up and the large sample size support effectiveness of the technique

  20. Fibre Tip Sensors for Localised Temperature Sensing Based on Rare Earth-Doped Glass Coatings

    Directory of Open Access Journals (Sweden)

    Erik P. Schartner

    2014-11-01

    Full Text Available We report the development of a point temperature sensor, based on monitoring upconversion emission from erbium:ytterbium-doped tellurite coatings on the tips of optical fibres. The dip coating technique allows multiple sensors to be fabricated simultaneously, while confining the temperature-sensitive region to a localised region on the end-face of the fibre. The strong response of the rare earth ions to changing temperature allows a resolution of 0.1–0.3 °C to be recorded over the biologically relevant range of temperatures from 23–39 °C.

  1. A Bayesian Change point model for differential gene expression patterns of the DosR regulon of Mycobacterium tuberculosis

    Directory of Open Access Journals (Sweden)

    Wernisch Lorenz

    2008-02-01

    Full Text Available Abstract Background Low oxygen availability has been shown previously to stimulate M. tuberculosis to establish non-replicative persistence in vitro. The two component sensor/regulator dosRS is a major mediator in the transcriptional response of M. tuberculosis to hypoxia and controls a regulon of approximately 50 genes that are induced under this condition. The aim of this study was to determine whether the induction of the entire DosR regulon is triggered as a synchronous event or if induction can unfold as a cascade of events as the differential expression of subsets of genes is stimulated by different oxygen availabilities. Results A novel aspect of our work is the use of chemostat cultures of M. tuberculosis which allowed us to control environmental conditions very tightly. We exposed M. tuberculosis to a sudden drop in oxygen availability in chemostat culture and studied the transcriptional response of the organism during the transition from a high oxygen level (10% dissolved oxygen tension or DOT to a low oxygen level (0.2% DOT using DNA microarrays. We developed a Bayesian change point analysis method that enabled us to detect subtle shifts in the timing of gene induction. It results in probabilities of a change in gene expression at certain time points. A computational analysis of potential binding sites upstream of the DosR-controlled genes shows how the transcriptional responses of these genes are influenced by the affinity of these binding sites to DosR. Our study also indicates that a subgroup of DosR-controlled genes is regulated indirectly. Conclusion The majority of the dosR-dependent genes were up-regulated at 0.2% DOT, which confirms previous findings that these genes are triggered by hypoxic environments. However, our change point analysis also highlights genes which were up-regulated earlier at levels of about 8% DOT indicating that they respond to small fluctuations in oxygen availability. Our analysis shows that there are

  2. Characterisation of MFM tip stray fields using Lorentz electron tomography

    CERN Document Server

    Scott, J

    2001-01-01

    considered, as is a possible improved design of DPC detector. distribution a tomographic method must be used. The collection and calibration of the tomographic data series is discussed, including the special sample mounting methods required. To understand the principles behind MFM, the theory behind atomic force microscopy (AFM) is discussed at length in Chapter 3. The extension of AFM to MFM is covered, and the simple point charge analysis of the MFM imaging process is reviewed. A more sophisticated analysis is then presented, based on the knowledge of the MFM point- response function. It is demonstrated that in some cases, the magnetic charge distribution of a samples can be extracted provided that the response function of the MFM tip (related directly to the stray field distribution from the tip) is known. Finally, some specialised MFM techniques are briefly reviewed. In Chapter 4, prototype tips (produced at Sheffield University) coated with a low-coercivity amorphous ferromagnetic alloy (METGLAS 2605SC) ...

  3. 复合肥转产注意事项%The points needing attention in production change of compound fertilizer

    Institute of Scientific and Technical Information of China (English)

    刘鹏飞; 靳丽丽; 张军

    2012-01-01

    Balanced fertilization needs to produce various formula compound fertilizer. The points needing attention in production change of compound fertilizer are introduced including optimizing formula, replacement of system backing material, key monitoring temperature and humidity of granulation material, controlling the washing and feeding system, and placement and detection of finished products.%平衡施肥要求生产多种配方的复合肥,介绍复合肥转产时应优化转产配方,注意系统底料的置换,重点监护造粒物料的温度和湿度,同时应注意控制好洗涤系统与上料系统,并注意转产后成品的放置与检测。

  4. Tips from the Trenches

    Science.gov (United States)

    Garofalo, Denise A.

    2012-01-01

    Branding and the idea that ebooks are still essentially books are important concepts to keep in mind, especially when confronted with all there is to oversee and consider in the arena of electronic resources; it is easy to feel overwhelmed by the torrent of change and the intricacies of the business. The author states that electronic resources…

  5. Optical fiber meta-tips

    Science.gov (United States)

    Principe, Maria; Micco, Alberto; Crescitelli, Alessio; Castaldi, Giuseppe; Consales, Marco; Esposito, Emanuela; La Ferrara, Vera; Galdi, Vincenzo; Cusano, Andrea

    2016-04-01

    We report on the first example of a "meta-tip" configuration that integrates a metasurface on the tip of an optical fiber. Our proposed design is based on an inverted-Babinet plasmonic metasurface obtained by patterning (via focused ion beam) a thin gold film deposited on the tip of an optical fiber, so as to realize an array of rectangular aperture nanoantennas with spatially modulated sizes. By properly tuning the resonances of the aperture nanoantennas, abrupt variations can be impressed in the field wavefront and polarization. We fabricated and characterized several proof-of-principle prototypes operating an near-infrared wavelengths, and implementing the beam-steering (with various angles) of the cross-polarized component, as well as the excitation of surface waves. Our results pave the way to the integration of the exceptional field-manipulation capabilities enabled by metasurfaces with the versatility and ubiquity of fiber-optics technological platforms.

  6. Nanotexturing of surfaces to reduce melting point.

    Energy Technology Data Exchange (ETDEWEB)

    Garcia, Ernest J.; Zubia, David (University of Texas at El Paso El Paso, TX); Mireles, Jose (Universidad Aut%C3%94onoma de Ciudad Ju%C3%94arez Ciudad Ju%C3%94arez, Mexico); Marquez, Noel (University of Texas at El Paso El Paso, TX); Quinones, Stella (University of Texas at El Paso El Paso, TX)

    2011-11-01

    This investigation examined the use of nano-patterned structures on Silicon-on-Insulator (SOI) material to reduce the bulk material melting point (1414 C). It has been found that sharp-tipped and other similar structures have a propensity to move to the lower energy states of spherical structures and as a result exhibit lower melting points than the bulk material. Such a reduction of the melting point would offer a number of interesting opportunities for bonding in microsystems packaging applications. Nano patterning process capabilities were developed to create the required structures for the investigation. One of the technical challenges of the project was understanding and creating the specialized conditions required to observe the melting and reshaping phenomena. Through systematic experimentation and review of the literature these conditions were determined and used to conduct phase change experiments. Melting temperatures as low as 1030 C were observed.

  7. Scanning tip measurement for identification of point defects

    OpenAIRE

    Raineri Vito; Giannazzo Filippo; Lányi Štefan; Dózsa László; Molnár György; Ferencz János

    2011-01-01

    Abstract Self-assembled iron-silicide nanostructures were prepared by reactive deposition epitaxy of Fe onto silicon. Capacitance-voltage, current-voltage, and deep level transient spectroscopy (DLTS) were used to measure the electrical properties of Au/silicon Schottky junctions. Spreading resistance and scanning probe capacitance microscopy (SCM) were applied to measure local electrical properties. Using a preamplifier the sensitivity of DLTS was increased satisfactorily to measure transien...

  8. ZBrush Professional Tips and Techniques

    CERN Document Server

    Gaboury, Paul

    2012-01-01

    Learn to work effectively and creatively with all versions of ZBrush! ZBrush is used by top artists in Hollywood to model and sculpt characters in such films as Avatar, Iron Man, and Pirates of the Caribbean. In addition, this amazing technology is also used in jewelry design, forensic science, aerospace, video games, toy creation, and the medical field. Written by Pixologic's in-house ZBrush expert Paul Gaboury, this full-color, beautifully illustrated guide provides you with the ultimate tips and tricks to maximize your use of all versions of ZBrush. Reveals numerous little-known tips and tr

  9. Self-sensing cantilevers with integrated conductive coaxial tips for high-resolution electrical scanning probe metrology

    Energy Technology Data Exchange (ETDEWEB)

    Haemmerli, Alexandre J.; Pruitt, Beth L., E-mail: pruitt@stanford.edu [Department of Mechanical Engineering, Stanford University, 440 Escondido Mall, Stanford, North Carolina 94305 (United States); Harjee, Nahid [Department of Electrical Engineering, Stanford University, 350 Serra Mall, Stanford, North Carolina 94305 (United States); Koenig, Markus; Garcia, Andrei G. F.; Goldhaber-Gordon, David [Department of Physics, Stanford University, 382 Via Pueblo Mall, Stanford, North Carolina 94305 (United States)

    2015-07-21

    The lateral resolution of many electrical scanning probe techniques is limited by the spatial extent of the electrostatic potential profiles produced by their probes. Conventional unshielded conductive atomic force microscopy probes produce broad potential profiles. Shielded probes could offer higher resolution and easier data interpretation in the study of nanostructures. Electrical scanning probe techniques require a method of locating structures of interest, often by mapping surface topography. As the samples studied with these techniques are often photosensitive, the typical laser measurement of cantilever deflection can excite the sample, causing undesirable changes electrical properties. In this work, we present the design, fabrication, and characterization of probes that integrate coaxial tips for spatially sharp potential profiles with piezoresistors for self-contained, electrical displacement sensing. With the apex 100 nm above the sample surface, the electrostatic potential profile produced by our coaxial tips is more than 2 times narrower than that of unshielded tips with no long tails. In a scan bandwidth of 1 Hz–10 kHz, our probes have a displacement resolution of 2.9 Å at 293 K and 79 Å at 2 K, where the low-temperature performance is limited by amplifier noise. We show scanning gate microscopy images of a quantum point contact obtained with our probes, highlighting the improvement to lateral resolution resulting from the coaxial tip.

  10. Twelve tips for peer observation of teaching.

    Science.gov (United States)

    Siddiqui, Zarrin Seema; Jonas-Dwyer, Diana; Carr, Sandra E

    2007-05-01

    This paper outlines twelve tips for undertaking peer observation of teaching in medical education, using the peer review model and the experiences of the authors. An accurate understanding of teaching effectiveness is required by individuals, medical schools, and universities to evaluate the learning environment and to substantiate academic and institutional performance. Peer Observation of Teaching is one tool that provides rich, qualitative evidence for teachers, quite different from closed-ended student evaluations. When Peer Observation of Teaching is incorporated into university practice and culture, and is conducted in a mutually respectful and supportive way, it has the potential to facilitate reflective change and growth for teachers.

  11. Tip of the iceberg

    DEFF Research Database (Denmark)

    Deriabyn, M. V.; Hjorth, Poul G.

    2009-01-01

    We study the stability and dynamics of melting icebergs. Specifically, we address the 'toppling' or 'rollover' observed for floating icebergs. The rollover is thought to occur because the ocean melts the iceberg from below, causing its overall mass and mass distribution to change with time. We...... model the evolution of equilibrium positions for a general homogeneous body afloat in an ideal fluid, as this homogeneous body is subjected to 'melting', i.e. a slow removal of material from the submerged part. If this process is the dominating melting mechanism, can the likelihood of a toppling...

  12. Scanning tip microwave near field microscope

    Science.gov (United States)

    Xiang, Xiao-Dong; Schultz, Peter G.; Wei, Tao

    1998-01-01

    A microwave near field microscope has a novel microwave probe structure wherein the probing field of evanescent radiation is emitted from a sharpened metal tip instead of an aperture or gap. This sharpened tip, which is electrically and mechanically connected to a central electrode, extends through and beyond an aperture in an endwall of a microwave resonating device such as a microwave cavity resonator or a microwave stripline resonator. Since the field intensity at the tip increases as the tip sharpens, the total energy which is radiated from the tip and absorbed by the sample increases as the tip sharpens. The result is improved spatial resolution without sacrificing sensitivity.

  13. Blade tip timing (BTT) uncertainties

    Science.gov (United States)

    Russhard, Pete

    2016-06-01

    Blade Tip Timing (BTT) is an alternative technique for characterising blade vibration in which non-contact timing probes (e.g. capacitance or optical probes), typically mounted on the engine casing (figure 1), and are used to measure the time at which a blade passes each probe. This time is compared with the time at which the blade would have passed the probe if it had been undergoing no vibration. For a number of years the aerospace industry has been sponsoring research into Blade Tip Timing technologies that have been developed as tools to obtain rotor blade tip deflections. These have been successful in demonstrating the potential of the technology, but rarely produced quantitative data, along with a demonstration of a traceable value for measurement uncertainty. BTT technologies have been developed under a cloak of secrecy by the gas turbine OEM's due to the competitive advantages it offered if it could be shown to work. BTT measurements are sensitive to many variables and there is a need to quantify the measurement uncertainty of the complete technology and to define a set of guidelines as to how BTT should be applied to different vehicles. The data shown in figure 2 was developed from US government sponsored program that bought together four different tip timing system and a gas turbine engine test. Comparisons showed that they were just capable of obtaining measurement within a +/-25% uncertainty band when compared to strain gauges even when using the same input data sets.

  14. Tips for Buying Exercise Equipment

    Science.gov (United States)

    ... esta página en español Tips for Buying Exercise Equipment Related Items Weight Loss Challenge Free Trials Can ... photo? What to Do Before You Buy Exercise Equipment You’ve done your job and looked at ...

  15. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

    Medline Plus

    Full Text Available ... children are more likely to be performed before liver transplant in those with ascites or variceal bleeding resistant to traditional medical treatments. The greatest difference in performing TIPS in children is their ... not be used for any purpose other than this referral.

  16. Top 10 Staff Survival Tips.

    Science.gov (United States)

    O'Brien, Laurie

    1995-01-01

    Tips for camp staff on how to survive summer camp include not giving campers sugary drinks before bedtime, setting behavior limits with campers, setting an example by following camp rules, getting enough rest, being fair and consistent, controlling anger, being accountable for actions, asking questions, and being flexible. (LP)

  17. Library Management Tips that Work

    Science.gov (United States)

    Smallwood, Carol, Ed.

    2011-01-01

    There's no shortage of library management books out there--but how many of them actually tackle the little details of day-to-day management, the hard-to-categorize things that slip through the cracks of a larger handbook? "Library Management Tips that Work" does exactly that, addressing dozens of such issues facing library managers, including: (1)…

  18. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

    Medline Plus

    Full Text Available ... overnight at the hospital for one or more days. What is Transjugular Intrahepatic Portosystemic Shunt (TIPS)? What are some common uses of the procedure? How should I prepare? What does the equipment look like? How does the procedure work? How is the procedure performed? What will I ...

  19. 99 Tips for Safe Schools.

    Science.gov (United States)

    Kaufer, Steve

    This pamphlet highlights 99 tips for maintaining safe schools. Areas of interest include: alarm systems and control of access, vandalism, parent education, transportation, school design, personnel training, and graffiti. The majority of the pointers deal with maintaining and implementing various forms of electronic surveillance and strategies for…

  20. Noise Characteristics of Centrifugal Blower with Low Solidity Cascade Diffuser (Noise Reduction by means of Small Groove Located at LSD Blade Leading Tip)

    Institute of Scientific and Technical Information of China (English)

    Tengen MURAKAMI; Masahiro ISHIDA; Daisaku SAKAGUCHI; Yu KOBA

    2009-01-01

    This paper deals with the effect of the blade tip-groove of the low solidity cascade diffuser (LSD) on the blower characteristic and the noise generated by the LSD. The small grooves were set up at the root and/or tip near the leading edge of the LSD blade. In order to clarify the mechanism of noise increase due to LSD and also to reduce the noise, the relationships between the noise increase based on the LSD, the LSD performance and the secondary flow formed additionally by the tip-groove were investigated experimentally as well as numerically, especially analyzing flow behaviors in the LSD in view points of flow separation on the suction surface of the LSD blade and the secondary flow on the side walls. By reducing the stagnation region smaller near the root and/or tip of the LSD blade leading edge, the secondary flow behavior changes remarkably around the LSD blade, as a result, the noise level and the blower characteristics vary. It can be concluded that, by means of a small tip-groove located only at the shroud side near the LSD blade leading edge, the noise generated by the LSD can be reduced without deteriorations of the LSD performance and the blower characteristics as well.

  1. Laser Guide Star Adaptive Optics without Tip-tilt

    CERN Document Server

    Davies, R; Lidman, C; Louarn, M Le; Kasper, M; Förster-Schreiber, N M; Roccatagliata, V; Ageorges, N; Amico, P; Dumas, C; Mannucci, F

    2008-01-01

    Adaptive optics (AO) systems allow a telescope to reach its diffraction limit at near infrared wavelengths. But to achieve this, a bright natural guide star (NGS) is needed for the wavefront sensing, severely limiting the fraction of the sky over which AO can be used. To some extent this can be overcome with a laser guide star (LGS). While the laser can be pointed anywhere in the sky, one still needs to have a natural star, albeit fainter, reasonably close to correct the image motion (tip-tilt) to which laser guide stars are insensitive. There are in fact many astronomical targets without suitable tip-tilt stars, but for which the enhanced resolution obtained with the Laser Guide Star Facility (LGSF) would still be very beneficial. This article explores what adaptive optics performance one might expect if one dispenses with the tip-tilt star, and in what situations this mode of observing might be needed.

  2. Twelve Tips for Promoting Significant Event Analysis To Enhance Reflection in Undergraduate Medical Students.

    Science.gov (United States)

    Henderson, Emma; Berlin, Anita; Freeman, George; Fuller, Jon

    2002-01-01

    Points out the importance of the facilitation of reflection and development of reflective abilities in professional development and describes 12 tips for undergraduate medical students to increase their abilities of writing reflective and creative event analysis. (Author/YDS)

  3. Optical Method for Real-Time Turbine Blade Tip Clearance Measurement Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Monitoring and controlling blade tip clearance of high pressure turbines are important for maintaining the integrity of the engine during its operating points and...

  4. Magnetic nondestructive testing of rotor blade tips

    Science.gov (United States)

    Cardelli, E.; Faba, A.; Marsili, R.; Rossi, G.; Tomassini, R.

    2015-05-01

    This paper deals with a particular magnetic nondestructive technique applied to the control of the position of the steel blades in rotating parts of turbines and engines. The working principle is based on a bridge of four identical magneto-resistive sensors. One sensor is placed near the blades, and the change in magnetic field produced by a permanent magnet and deviated by the change in position of the blade is detected by the sensor bridge. The position of the sensor is indicated, via dedicated FEM simulations, in order to have high sensitivity to the position change and high output signal. The accuracy and effectiveness of the proposed method are shown by experimental tests carried out in our laboratories. In particular, the tests indicate that the proposed magnetic nondestructive technique can be used in an almost large velocity range, and for quite different values of blade tip. The method seems also promising for the detection of blade vibrations.

  5. Mini-flared Kelman tip, reverse tip, and sidewinder tip with torsional phaco: a prospective randomized comparative study

    Directory of Open Access Journals (Sweden)

    Wilson Takashi Hida

    2015-02-01

    Full Text Available Purpose: To compare the efficiency of surgical procedures using three phaco tip designs in torsional phacoemulsification using the bevel-down technique. Methods: In this prospective, comparative, masked study, patients were randomly assigned to have torsional coaxial microincision cataract surgery using the mini-flared 45-degree Kelman tip, reversed mini-flared 30-degree Kelman tip, or Sidewinder 30-degree Kelman tip. Clinical measurements included preoperative and 3-month postoperative corrected distance visual acuity (CDVA, endothelial cell counts (ECC, and preoperative and 1-day postoperative central corneal thickness (CCT. Intraoperative measurements included phaco time, torsional time, aspiration time, case time, cumulative dissipated energy (CDE, and balanced salt solution volume (BSS. Results: The study evaluated 150 eyes of 150 patients. Intraoperatively, there was no statistically significant difference in cumulative dissipated energy, case time, torsional time, and aspiration time between the three tip configurations. However, less phaco time was used with the mini-flared 45-degree Kelman tip (p=0.02 than that with the Sidewinder 30-degree Kelman tip or reversed mini-flared 30-degree Kelman tip. The mini-flared 45-degree Kelman tip and the reversed mini-flared 30-degree Kelman tip required significantly less balanced salt solution volume than that required by the Sidewinder 30-degree Kelman tip (p=0.009. There was no statistically significant difference in corrected distance visual acuity and endothelial cell counts between tips 3 months postoperatively (p>0.05. Conclusion: All three tips were effective with no intraoperative complications. When using torsional phacoemulsification through microincisions and the prefracture technique with the bevel-down technique, the mini-flared 45-degree Kelman tip required a lower mean phaco time than the reversed mini-flared 30-degree Kelman tip and the Sidewinder 30-degree Kelman tip.

  6. 不同矫治方法对口呼吸所致安Ⅱ1错(牙合)患者硬组织影响的比较研究%Effects of the cephelometric change in Angles Ⅱ malocclusion becaused of mouth - breathing with Tip - Edge and RME unite Tip- Edge technology

    Institute of Scientific and Technical Information of China (English)

    姚霜; 刘晓君; 杨霜; 杨苹; 徐明

    2005-01-01

    目的寻求口呼吸所致安Ⅱ1错(牙合)畸形患者的有效治疗方法.方法在28例恒牙期口呼吸所致安Ⅱ1错(牙合)患者中,有16例采用Tip-Edge差动直丝弓技术进行矫治;另外12例以快速扩弓联合Tip-Edge技术进行矫治,用图像数字化X线头颅定位摄片仪,作治疗前后X线头影测量对比分析,并进行统计学检验.结果联合治疗组S-Go增加3.21mm,U6-PP、L6-MP分别减小1.63mm和1.42mm,Yaxis、SN-MP、FH-MP和SN-PP均较治疗前明显减小,与单纯组比较有显著性差异;两个组治疗后的SNB、U1-L1和Go-Pg及等测量值明显增大,ANB则明显减小,但两组间比较无显著性差异.结论对口呼吸所致的安Ⅱ1错(牙合)患者而言,采用快速上颌扩展联合Tip-Edge差动直丝弓技术进行治疗,更有利于垂直向的控制.

  7. Climate tipping as a noisy bifurcation: a predictive technique

    CERN Document Server

    Thompson, J M T

    2010-01-01

    It is often known, from modelling studies, that a certain mode of climate tipping (of the oceanic thermohaline circulation, for example) is governed by an underlying fold bifurcation. For such a case we present a scheme of analysis that determines the best stochastic fit to the existing data. This provides the evolution rate of the effective control parameter, the variation of the stability coefficient, the path itself and its tipping point. By assessing the actual effective level of noise in the available time series, we are then able to make probability estimates of the time of tipping. This new technique is applied, first, to the output of a computer simulation for the end of greenhouse Earth about 34 million years ago when the climate tipped from a tropical state into an icehouse state with ice caps. Second, we use the algorithms to give probabilistic tipping estimates for the end of the most recent glaciation of the Earth using actual archaeological ice-core data.

  8. Note on Studying Change Point of LRD Traffic Based on Li's Detection of DDoS Flood Attacking

    Directory of Open Access Journals (Sweden)

    Zhengmin Xia

    2010-01-01

    Full Text Available Distributed denial-of-service (DDoS flood attacks remain great threats to the Internet. To ensure network usability and reliability, accurate detection of these attacks is critical. Based on Li's work on DDoS flood attack detection, we propose a DDoS detection method by monitoring the Hurst variation of long-range dependant traffic. Specifically, we use an autoregressive system to estimate the Hurst parameter of normal traffic. If the actual Hurst parameter varies significantly from the estimation, we assume that DDoS attack happens. Meanwhile, we propose two methods to determine the change point of Hurst parameter that indicates the occurrence of DDoS attacks. The detection rate associated with one method and false alarm rate for the other method are also derived. The test results on DARPA intrusion detection evaluation data show that the proposed approaches can achieve better detection performance than some well-known self-similarity-based detection methods.

  9. Tips for Traveling with HomePEN

    Science.gov (United States)

    ... Keep Private Resources: Travel Tips Share | Tips for Traveling with HomePEN A little preparation can go a ... on your Behalf (12/2010) Other Articles on Travel TSA Program Aims to Help Elderly, Disabled, Sick ...

  10. Tips to Manage Anxiety and Stress

    Science.gov (United States)

    ... Journal & Multimedia Resources Awards Consumers Tips to Manage Anxiety and Stress Main navigation Tips Severe Storms: How to Reduce Your Anxiety Anxiety and Stress in the Workplace Exercise for Stress and Anxiety ...

  11. 变化 Wiener指数的变点研究%Change Point of Variable Wiener Index

    Institute of Scientific and Technical Information of China (English)

    陈志琳; 王志远; 林宁; 高鸿杰; 贾珍; 魏福义

    2014-01-01

    Wiener index ,set up by Harold Wiener ,is an important topological index widely used in chemical research . The variable Wiener index is as the Wiener index improved by some people such as I .Gutman ,M .H .Liu ,with his partners , have proved the extremal graph of the trees'largest variable Wiener index ,when given the maximum degree Δ≥ n/2 .In this dissertation ,numerical calculation is used to study the variable Wiener index between tree F(n ,Δ) and H(n ,Δ) .Finally ,the change point λ0 is finally worked out ,which depicts the variable Wiener index between tree F(n ,Δ) and H(n ,Δ) ,as well as the change rule betweennand Δ,and extremal graph of the second largest (smallest) variable Wiener index when given the maximum degree .In particular ,the change rule when Δ< n/2 is figured out .%Wiener指数是 Harold Wiener提出的广泛应用于化学研究中的一个重要拓扑指数。I .Gutman等把Wiener指数推广为变化Wiener指数。M .H .Liu等给出了最大度Δ≥ n/2时,树中最大的变化Wiener指数的极图。论文用数值计算方法研究了树 F(n ,Δ)和 H(n ,Δ)的变化Wiener指数的大小关系,得到了刻画树 F(n ,Δ)和树 H (n ,Δ)的变化Wiener指数大小关系的变点λ0和 n ,Δ之间的变化规律,以及给定最大度的树中次大(小)的变化Wiener指数的极图。特别地,得出Δ< n/2时的变化规律。

  12. Investigation of Turbulent Tip Leakage Vortex in an Axial Water Jet Pump with Large Eddy Simulation

    Science.gov (United States)

    Hah, Chunill; Katz, Joseph

    2012-01-01

    Detailed steady and unsteady numerical studies were performed to investigate tip clearance flow in an axial water jet pump. The primary objective is to understand physics of unsteady tip clearance flow, unsteady tip leakage vortex, and cavitation inception in an axial water jet pump. Steady pressure field and resulting steady tip leakage vortex from a steady flow analysis do not seem to explain measured cavitation inception correctly. The measured flow field near the tip is unsteady and measured cavitation inception is highly transient. Flow visualization with cavitation bubbles shows that the leakage vortex is oscillating significantly and many intermittent vortex ropes are present between the suction side of the blade and the tip leakage core vortex. Although the flow field is highly transient, the overall flow structure is stable and a characteristic frequency seems to exist. To capture relevant flow physics as much as possible, a Reynolds-averaged Navier-Stokes (RANS) calculation and a Large Eddy Simulation (LES) were applied for the current investigation. The present study reveals that several vortices from the tip leakage vortex system cross the tip gap of the adjacent blade periodically. Sudden changes in local pressure field inside tip gap due to these vortices create vortex ropes. The instantaneous pressure filed inside the tip gap is drastically different from that of the steady flow simulation. Unsteady flow simulation which can calculate unsteady vortex motion is necessary to calculate cavitation inception accurately even at design flow condition in such a water jet pump.

  13. Smoking - tips on how to quit

    Science.gov (United States)

    Cigarettes - tips on how to quit; Smoking cessation - tips on how to quit; Smokeless tobacco - tips on how to quit ... There are many ways to quit smoking. There are also resources to ... co-workers may be supportive. But to be successful, you must ...

  14. The Social Cost of Stochastic and Irreversible Climate Change

    Science.gov (United States)

    Cai, Y.; Judd, K. L.; Lontzek, T.

    2013-12-01

    Many scientists are worried about climate change triggering abrupt and irreversible events leading to significant and long-lasting damages. For example, a rapid release of methane from permafrost may lead to amplified global warming, and global warming may increase the frequency and severity of heavy rainfall or typhoon, destroying large cities and killing numerous people. Some elements of the climate system which might exhibit such a triggering effect are called tipping elements. There is great uncertainty about the impact of anthropogenic carbon and tipping elements on future economic wellbeing. Any rational policy choice must consider the great uncertainty about the magnitude and timing of global warming's impact on economic productivity. While the likelihood of tipping points may be a function of contemporaneous temperature, their effects are long lasting and might be independent of future temperatures. It is assumed that some of these tipping points might occur even in this century, but also that their duration and post-tipping impact are uncertain. A faithful representation of the possibility of tipping points for the calculation of social cost of carbon would require a fully stochastic formulation of irreversibility, and accounting for the deep layer of uncertainties regarding the duration of the tipping process and also its economic impact. We use DSICE, a DSGE extension of the DICE2007 model of William Nordhaus, which incorporates beliefs about the uncertain economic impact of possible climate tipping events and uses empirically plausible parameterizations of Epstein-Zin preferences to represent attitudes towards risk. We find that the uncertainty associated with anthropogenic climate change imply carbon taxes much higher than implied by deterministic models. This analysis indicates that the absence of uncertainty in DICE2007 and similar IAM models may result in substantial understatement of the potential benefits of policies to reduce GHG emissions.

  15. The effect of TIP on pneumovirus-induced pulmonary edema in mice.

    Directory of Open Access Journals (Sweden)

    Elske van den Berg

    Full Text Available BACKGROUND: Pulmonary edema plays a pivotal role in the pathophysiology of respiratory syncytial virus (RSV-induced respiratory failure. In this study we determined whether treatment with TIP (AP301, a synthetic cyclic peptide that mimics the lectin-like domain of human TNF, decreases pulmonary edema in a mouse model of severe human RSV infection. TIP is currently undergoing clinical trials as a therapy for pulmonary permeability edema and has been shown to decrease pulmonary edema in different lung injury models. METHODS: C57BL/6 mice were infected with pneumonia virus of mice (PVM and received TIP or saline (control group by intratracheal instillation on day five (early administration or day seven (late administration after infection. In a separate set of experiments the effect of multiple dose administration of TIP versus saline was tested. Pulmonary edema was determined by the lung wet-to-dry (W/D weight ratio and was assessed at different time-points after the administration of TIP. Secondary outcomes included clinical scores and lung cellular response. RESULTS: TIP did not have an effect on pulmonary edema in different dose regimens at different time points during PVM infection. In addition, TIP administration did not affect clinical severity scores or lung cellular response. CONCLUSION: In this murine model of severe RSV infection TIP did not affect pulmonary edema nor course of disease.

  16. Optical Fiber Tip Pressure Sensor

    OpenAIRE

    Wang, Xingwei

    2004-01-01

    Miniature pressure sensors which can endure harsh environments are a highly sought after goal in industrial, medical and research fields. Microelectromechanical systems (MEMS) are the current methods to fabricate such small sensors. However, they suffer from low sensitivity and poor mechanical properties. To fulfill the need for robust and reliable miniature pressure sensors that can operate under high temperatures, a novel type of optical fiber tip sensor only 125μm in diameter is ...

  17. Management of the droopy tip: a comparison of three alar cartilage-modifying techniques.

    Science.gov (United States)

    Foda, Hossam M T

    2003-10-01

    The droopy tip is a common nasal deformity in which the tip is inferiorly rotated. Five hundred consecutive rhinoplasty cases were studied to assess the incidence and causes of the droopy tip deformity and to evaluate the role of three alar cartilage-modifying techniques--lateral crural steal, lateral crural overlay, and tongue in groove--in correcting such a deformity. The external rhinoplasty approach was used in all cases. Only one of the three alar cartilage-modifying techniques was used in each case, and the degree of tip rotation and projection was measured both preoperatively and postoperatively. The incidence of droopy tip was 72 percent, and the use of an alar cartilage-modifying technique was required in 85 percent of these cases to achieve the desired degree of rotation. The main causes of droopy tip included inferiorly oriented alar cartilages (85 percent), overdeveloped scrolls of upper lateral cartilages (73 percent), high anterior septal angle (65 percent), and thick skin of the nasal lobule (56 percent). The lateral crural steal technique increased nasal tip rotation and projection, the lateral crural overlay technique increased tip rotation and decreased tip projection, and the tongue-in-groove technique increased tip rotation without significantly changing the amount of projection. The lateral crural overlay technique resulted in the highest degrees of rotation, followed by the lateral crural steal and finally the tongue-in-groove technique. According to these results, the lateral crural steal technique is best indicated in cases with droopy underprojected nasal tip, the lateral crural overlay technique in cases of droopy overprojected nasal tip, and the tongue-in-groove technique in cases where the droopy nasal tip is associated with an adequate amount of projection. PMID:14504527

  18. Alternating tip splitting in directional solidification.

    Science.gov (United States)

    Utter, B; Ragnarsson, R; Bodenschatz, E

    2001-05-14

    We report experimental results on the tip splitting dynamics of seaweed growth in directional solidification of succinonitrile alloys. Despite the random appearance of the growth, a tip splitting morphology was observed in which the tip alternately splits to the left and to the right. The tip splitting frequency f was found to be related to the growth velocity V as a power law f~V1.5. This finding is consistent with the predictions of a tip splitting model that is also presented. Small anisotropies are shown to lead to different kinds of seaweed morphologies.

  19. Spontaneous migration of central venous catheter tip following extubation

    Directory of Open Access Journals (Sweden)

    Balaji Prabaharan

    2014-01-01

    Full Text Available Migration of the tip of central venous catheters is not an uncommon event and the mechanism for this is not clear. Increased intrathoracic pressure due to coughing, sneezing or weight lifting, changing the body position or physical movements such as abduction or adduction of the arms is thought to be the cause of such migration. We present here a case of a patient with a port catheter tip that migrated from the left subclavian to the superior vene cava following extubation.

  20. Nanoparticle Shape Evolution and Proximity Effects During Tip-Induced Electrochemical Processes.

    Science.gov (United States)

    Yang, Sang Mo; Paranthaman, Mariappan Parans; Noh, Tae Won; Kalinin, Sergei V; Strelcov, Evgheni

    2016-01-26

    Voltage spectroscopies in scanning probe microscopy (SPM) techniques are widely used to investigate the electrochemical processes in nanoscale volumes, which are important for current key applications, such as batteries, fuel cells, catalysts, and memristors. The spectroscopic measurements are commonly performed on a grid of multiple points to yield spatially resolved maps of reversible and irreversible electrochemical functionalities. Hence, the spacing between measurement points is an important parameter to be considered, especially for irreversible electrochemical processes. Here, we report nonlocal electrochemical dynamics in chains of Ag particles fabricated by the SPM tip on a silver ion solid electrolyte. When the grid spacing is small compared with the size of the formed Ag particles, anomalous chains of unequally sized particles with double periodicity evolve. This behavior is ascribed to a proximity effect during the tip-induced electrochemical process, specifically, size-dependent silver particle growth following the contact between the particles. In addition, fractal shape evolution of the formed Ag structures indicates that the growth-limiting process changes from Ag(+)/Ag redox reaction to Ag(+)-ion diffusion with the increase in the applied voltage and pulse duration. This study shows that characteristic shapes of the electrochemical products are good indicators for determining the underlying growth-limiting process, and emergence of complex phenomena during spectroscopic mapping of electrochemical functionalities.

  1. Effects of increasing tip velocity on wind turbine rotor design.

    Energy Technology Data Exchange (ETDEWEB)

    Resor, Brian Ray; Maniaci, David Charles; Berg, Jonathan Charles; Richards, Phillip William

    2014-05-01

    A reduction in cost of energy from wind is anticipated when maximum allowable tip velocity is allowed to increase. Rotor torque decreases as tip velocity increases and rotor size and power rating are held constant. Reduction in rotor torque yields a lighter weight gearbox, a decrease in the turbine cost, and an increase in the capacity for the turbine to deliver cost competitive electricity. The high speed rotor incurs costs attributable to rotor aero-acoustics and system loads. The increased loads of high speed rotors drive the sizing and cost of other components in the system. Rotor, drivetrain, and tower designs at 80 m/s maximum tip velocity and 100 m/s maximum tip velocity are created to quantify these effects. Component costs, annualized energy production, and cost of energy are computed for each design to quantify the change in overall cost of energy resulting from the increase in turbine tip velocity. High fidelity physics based models rather than cost and scaling models are used to perform the work. Results provide a quantitative assessment of anticipated costs and benefits for high speed rotors. Finally, important lessons regarding full system optimization of wind turbines are documented.

  2. Performance comparison of fiber optic tips in interferrometric displacement measurement

    Energy Technology Data Exchange (ETDEWEB)

    Moro, Erik A [Los Alamos National Laboratory; Puckett, Anthony D [Los Alamos National Laboratory; Grahn, Rick [UNM; Karimi, Hussain [UCSD; Wilson, Kyle [ROSE HULMAN INSTITUTE OT TECH.

    2010-10-21

    Fiber optic displacement sensors have many potential advantages over traditional displacement measurement techniques, including small size, immunity to electromagnetic interference, electrical isolation, and high resolution. In this report, we focus on an interferometric fiber optic sensor, where the gap between the fiber tip and the device under test forms a Fabry-Perot resonant cavity. An optical interrogator measures the reflected intensity at wavelengths ranging from 1510 to 1590 nm. The spacing between resonant frequencies allows us to determine the distance from the tip to the device under test. We consider ferrule connector angled physical contact (FC/APC), ferrule connector ultra physical contact (FC/UPC) and unpolished cleaved tips and compare their influence on sensor performance. A plane wave propagation model is proposed for predicting tip effects. Comparisons are made on the basis of sensor measurement range, resolution, and sensitivity to changes in test conditions. In this paper, we discuss the experimental setup, detail our analysis, and present test results with recommendations for the applications of each tip.

  3. Twelve tips to revitalise problem-based learning.

    Science.gov (United States)

    Wood, Sarah J; Woywodt, Alexander; Pugh, Mark; Sampson, Ian; Madhavi, Paladugu

    2014-11-17

    Abstract The role of the problem-based learning (PBL) facilitator has seen different interpretations ever since PBL first gained widespread use. What has remained unchanged is the challenge for facilitators to use their knowledge and expertise sparingly and to use their interpersonal skills to improve group dynamics. Medical undergraduates attending PBL sessions have also changed in their skill sets, expectations and the use of technology. Based on the published literature and a recent faculty workshop, we provide PBL facilitators and institutions with 12 tips on how to make PBL more vibrant and interesting. We discuss our tips with reference to published literature and International Academy of Medical Education (AMEE) guidance. Our tips help students to engage with PBL, avoid monotony and make this teaching format more vibrant and fun for all involved. Introducing greater variety to the PBL process may also help with group dynamics by catering for a broader audience with different learning styles. PMID:25401407

  4. Changes in the spectral composition of animal-brain electrical activity under the influence of nonthermal millimeter-wave radiation on acupuncture points

    Energy Technology Data Exchange (ETDEWEB)

    Khramov, R.N.; Vorob`ev, V.V.

    1994-07-01

    The frequency spectra (0-26 Hz) of electrograms (EG) of the preoptic region of the hypothalamus were studied in chronic experiments on nine awake rabbits under the influence of nonthermal millimeter-bank (55-75 GHz) electromagnetic fields on various acupuncture points: (I) the auricular {open_quotes}heart{close_quotes} point (after F. G. Portnov); (II) the cranial acupoint (TR-20; the {open_quotes}hypothalamus{close_quotes} point after R. Voll); and (III) the {open_quotes}longevity{close_quotes} acupoint (E-36). Irradiation of point I was accompanied by significant suppression of hypothalamic electrical activity at 5 and 16 Hz and enhancement at 7-8, 12, and 26 Hz. Irradiation of point II, and III were, respectively, 31%, 21%, and 5% (p < 0.05, U-criterion). These results suggest that acupuncture points I and II are more sensitive to millimeter-band radiation than is point III. The presence of individual characteristics of the effects and their change after stress to sign inversion were shown in rat experiments in which the acupuncture points were irradiated.

  5. Comparison of Various Supersonic Turbine Tip Designs to Minimize Aerodynamic Loss and Tip Heating

    Science.gov (United States)

    Shyam, Vikram; Ameri, Ali

    2012-01-01

    The rotor tips of axial turbines experience high heat flux and are the cause of aerodynamic losses due to tip clearance flows, and in the case of supersonic tips, shocks. As stage loadings increase, the flow in the tip gap approaches and exceeds sonic conditions. This introduces effects such as shock-boundary layer interactions and choked flow that are not observed for subsonic tip flows that have been studied extensively in literature. This work simulates the tip clearance flow for a flat tip, a diverging tip gap and several contoured tips to assess the possibility of minimizing tip heat flux while maintaining a constant massflow from the pressure side to the suction side of the rotor, through the tip clearance. The Computational Fluid Dynamics (CFD) code GlennHT was used for the simulations. Due to the strong favorable pressure gradients the simulations assumed laminar conditions in the tip gap. The nominal tip gap width to height ratio for this study is 6.0. The Reynolds number of the flow is 2.4 x 10(exp 5) based on nominal tip width and exit velocity. A wavy wall design was found to reduce heat flux by 5 percent but suffered from an additional 6 percent in aerodynamic loss coefficient. Conventional tip recesses are found to perform far worse than a flat tip due to severe shock heating. Overall, the baseline flat tip was the second best performer. A diverging converging tip gap with a hole was found to be the best choice. Average tip heat flux was reduced by 37 percent and aerodynamic losses were cut by over 6 percent.

  6. An effective algorithm for needle tip displacement compensation in robot-assisted percutaneous surgery

    Institute of Scientific and Technical Information of China (English)

    Sun Yinshan; Wu Dongmei; Du Zhijiang; Sun Lining

    2010-01-01

    This paper presents an automatic compensation algorithm for needle tip displacement in order to keep the needle tip always fixed at the skin entry point in the process of needle orientation in robot-assisted percutaneous surgery.The algorithm, based on a two-degree-of-freedom (2-DOF) robot wrist (not the mechanically constrained remote center of motion (RCM) mechanism) and a 3-DOF robot arm, firstly calculates the needle tip displacement caused by rotational motion of robot wrist in the arm coordinate frame using the robotic forward kinematics, and then inversely compensates for the needle tip displace-ment by real-time Cartesian motion of robot arm.The algorithm achieves the function of the RCM and eliminates many mechanical and virtual constraints caused by the RCM mechanism.Experimental result demonstrates that the needle tip displacement is within 1 mm in the process of needle orientation.

  7. A 3D clustering approach for point clouds to detect and quantify changes at a rock glacier front

    Science.gov (United States)

    Micheletti, Natan; Tonini, Marj; Lane, Stuart N.

    2016-04-01

    Terrestrial Laser Scanners (TLS) are extensively used in geomorphology to remotely-sense landforms and surfaces of any type and to derive digital elevation models (DEMs). Modern devices are able to collect many millions of points, so that working on the resulting dataset is often troublesome in terms of computational efforts. Indeed, it is not unusual that raw point clouds are filtered prior to DEM creation, so that only a subset of points is retained and the interpolation process becomes less of a burden. Whilst this procedure is in many cases necessary, it implicates a considerable loss of valuable information. First, and even without eliminating points, the common interpolation of points to a regular grid causes a loss of potentially useful detail. Second, it inevitably causes the transition from 3D information to only 2.5D data where each (x,y) pair must have a unique z-value. Vector-based DEMs (e.g. triangulated irregular networks) partially mitigate these issues, but still require a set of parameters to be set and a considerable burden in terms of calculation and storage. Because of the reasons above, being able to perform geomorphological research directly on point clouds would be profitable. Here, we propose an approach to identify erosion and deposition patterns on a very active rock glacier front in the Swiss Alps to monitor sediment dynamics. The general aim is to set up a semiautomatic method to isolate mass movements using 3D-feature identification directly from LiDAR data. An ultra-long range LiDAR RIEGL VZ-6000 scanner was employed to acquire point clouds during three consecutive summers. In order to isolate single clusters of erosion and deposition we applied the Density-Based Scan Algorithm with Noise (DBSCAN), previously successfully employed by Tonini and Abellan (2014) in a similar case for rockfall detection. DBSCAN requires two input parameters, strongly influencing the number, shape and size of the detected clusters: the minimum number of

  8. Tip60 HAT Action Mediates Environmental Enrichment Induced Cognitive Restoration.

    Science.gov (United States)

    Xu, Songjun; Panikker, Priyalakshmi; Iqbal, Sahira; Elefant, Felice

    2016-01-01

    Environmental enrichment (EE) conditions have beneficial effects for reinstating cognitive ability in neuropathological disorders like Alzheimer's disease (AD). While EE benefits involve epigenetic gene control mechanisms that comprise histone acetylation, the histone acetyltransferases (HATs) involved remain largely unknown. Here, we examine a role for Tip60 HAT action in mediating activity- dependent beneficial neuroadaptations to EE using the Drosophila CNS mushroom body (MB) as a well-characterized cognition model. We show that flies raised under EE conditions display enhanced MB axonal outgrowth, synaptic marker protein production, histone acetylation induction and transcriptional activation of cognition linked genes when compared to their genotypically identical siblings raised under isolated conditions. Further, these beneficial changes are impaired in both Tip60 HAT mutant flies and APP neurodegenerative flies. While EE conditions provide some beneficial neuroadaptive changes in the APP neurodegenerative fly MB, such positive changes are significantly enhanced by increasing MB Tip60 HAT levels. Our results implicate Tip60 as a critical mediator of EE-induced benefits, and provide broad insights into synergistic behavioral and epigenetic based therapeutic approaches for treatment of cognitive disorder. PMID:27454757

  9. Smart Pipette and Microfluidic Pipette Tip for Blood Plasma Separation.

    Science.gov (United States)

    Kim, Byeongyeon; Choi, Sungyoung

    2016-01-13

    An integrated method for blood plasma separation is presented by combining a pneumatic device, which is referred to as a "smart pipette," and a hydrophoretic microchannel as a microfluidic pipette tip for whole-blood sample preparation. This method enables hemolysis-free, high-purity plasma separation through smart pipetting of whole blood, potentially providing the means for rapid, inexpensive blood sample preparation for point-of-care testing.

  10. Scintigraphic evaluation of hepatic blood flow after intrahepatic portosystemic shunt (TIPS).

    Science.gov (United States)

    Menzel, J; Schober, O; Reimer, P; Domschke, W

    1997-06-01

    In patients with liver cirrhosis a transjugularly placed intrahepatic portocaval shunt (TIPS) is a non-surgical portosystemic device which aims to reduce portal venous pressure. In comparison with Doppler sonography, we evaluated in 28 patients the diagnostic impact of liver perfusion scintigraphy (with technetium-99m diethylene triamine penta-acetic acid) in the assessment of changes in the hepatic blood flow after TIPS shunting. The arterial and portal contributions to hepatic flow were calculated from the areas under the biphasic time-activity curve. In the course of TIPS shunting, patency is threatened by reocclusion. Angiography is the gold standard for TIPS shunt reassessment. However, there is a need for a less invasive diagnostic procedure, such as scintigraphy or Doppler sonography, for the early detection of shunt insufficiency. Scintigraphy demonstrated that prior to TIPS shunting the portal venous contribution to hepatic perfusion was reduced to 29.2%, this reduction being due to portal hypertension. After TIPS placement a significant increase in portal venous perfusion was observed (38.2%; Pscintigraphically measured portal venous contribution to hepatic blood flow. Hepatic perfusion scintigraphy appears to be a valuable method to determine the immediate effect of TIPS on hepatic blood flow. Post-TIPS follow-up studies of hepatic haemodynamics by liver perfusion scintigraphy appear able to contribute to the detection of TIPS shunt occlusion before the clinical consequences of this complication have become apparent. PMID:9169570

  11. Antropontologija kao novi tip ontologije

    OpenAIRE

    Çotuksöken, Betül

    2013-01-01

    Antropontologija kao filozofski diskurs razlikuje se od klasične ontologije, fenomenološke ontologije, ontologije biti i nove ontologije. Poznato je da su različiti ontološki pogledi doveli do različitih prijelomnih točaka u povijesti filozofije. Antropontologija nudi novi tip ontologije koji se ustvari usredotočuje posebice na ljudska bića kao početnu točku. Što obuhvaća filozofski napor koji nastoji analizirati veze između ljudskog bića i znanja svijeta u svjetlu antropontologije? Što antro...

  12. Dark tip-tilt sensing

    CERN Document Server

    Arcidiacono, Carmelo; Viotto, Valentina; Bergomi, Maria; Farinato, Jacopo; Magrin, Demetrio; Dima, Marco; Gullieuszik, Marco; Marafatto, Luca

    2016-01-01

    Dark wavefront sensing in its simplest and more crude form is a quad-cell with a round spot of dark ink acting as occulting disk at the center. This sensor exhibits fainter limiting magnitude than a conventional quad-cell, providing that the size of the occulting disk is slightly smaller than the size of the spot and smaller than the residual jitter movement in closed loop. We present simulations focusing a generic Adaptive Optics system using Natural Guide Stars to provide the tip-tilt signal. We consider a jitter spectrum of the residual correction including amplitudes exceeding the dark disk size.

  13. Windows 8 visual quick tips

    CERN Document Server

    McFedries, Paul

    2012-01-01

    Easy-in, easy-out format covers all the bells and whistles of Windows 8 If you want to learn how to work smarter and faster in Microsoft's Windows 8 operating system, this easy-to-use, compact guide delivers the goods. Designed for visual learners, it features short explanations and full-color screen shots on almost every page, and it's packed with timesaving tips and helpful productivity tricks. From enhancing performance and managing digital content to setting up security and much more, this handy guide will help you get more out of Windows 8. Uses full-color screen shots and short, step-by-

  14. Fifteen tips for success in injury prevention.

    Science.gov (United States)

    Judkins, Daniel G

    2009-01-01

    Fifteen tips for success in injury prevention include the following: (1) make a plan; (2) understand injury epidemiology; (3) read, learn, and get educated; (4) show me the data; (5) select prevention strategies thoughtfully; (6) define risk factors and understand risk taking; (7) evaluate; (8) schedule a lunch meeting; (9) use principles of health behavior change, adult education theory, and communication theory; (10) be friends with the marketing and public affairs people; (11) recognize the fact that people are more emotional about injury in children than in adults; (12) understand cost-benefits and payoffs; (13) get stuff; (14) report your results; and (15) be patient. Several useful tables for basic references to resources in injury prevention are included. PMID:20029280

  15. Positive Changes in Perceptions and Selections of Healthful Foods by College Students after a Short-Term Point-of-Selection Intervention at a Dining Hall

    Science.gov (United States)

    Peterson, Sharon; Duncan, Diana Poovey; Null, Dawn Bloyd; Roth, Sara Long; Gill, Lynn

    2010-01-01

    Objective: Determine the effects of a short-term, multi-faceted, point-of-selection intervention on college students' perceptions and selection of 10 targeted healthful foods in a university dining hall and changes in their self-reported overall eating behaviors. Participants: 104 college students, (age 18-23) completed pre-I and post-I surveys.…

  16. The Teratogenic Potencies of Valproic Acid Derivatives and Their Effects on Biological End-points are Related to Changes in Histone Deacetylase and Erk1/2 Activities

    DEFF Research Database (Denmark)

    Gotfryd, Kamil; Hansen, Maria; Kawa, Anna;

    2011-01-01

    changes in cell proliferation, growth, cell cycle distribution, morphology, speed, glycogen synthase kinase-3ß (GSK-3ß) and Erk1/2 phosphorylation, and histone H3 acetylation. Changes in proliferation, growth, speed, Erk1/2 and GSK-3ß-Tyr216 phosphorylation, and H3 acetylation were significantly...... associated with the teratogenic potencies of the VPA derivatives. However, in contrast to changes in Erk1/2 phosphorylation and H3 acetylation, significant changes in GSK-3ß phosphorylation could only be obtained in response to prolonged incubation at high drug concentration. There was an association between...... changes in H3 acetylation and GSK-3ß-Tyr216 phosphorylation, whereas none of these end-points were associated with changes in Erk1/2 phosphorylation. These results suggest that the teratogenic potencies of VPA and VPA derivatives are related to effects on both Erk1/2 and histone deacetylase activities...

  17. Direct calculation of wind turbine tip loss

    DEFF Research Database (Denmark)

    Wood, D.H.; Okulov, Valery; Bhattacharjee, D.

    2016-01-01

    The usual method to account for a finite number of blades in blade element calculations of wind turbine performance is through a tip loss factor. Most analyses use the tip loss approximation due to Prandtl which is easily and cheaply calculated but is known to be inaccurate at low tip speed ratio....... We develop three methods for the direct calculation of the tip loss. The first is the computationally expensive calculation of the velocities induced by the helicoidal wake which requires the evaluation of infinite sums of products of Bessel functions. The second uses the asymptotic evaluation...... of those sums by Kawada. The third uses the approximation due to Okulov which avoids the sums altogether. These methods are compared to the tip loss determined independently and exactly for an ideal three-bladed rotor at tip speed ratios between zero and 15. Kawada's asymptotic approximation and Okulov...

  18. Immobilized diaphorase surfaces observed by scanning electrochemical microscope with shear force based tip-substrate positioning.

    Science.gov (United States)

    Yamada, Hiroshi; Fukumoto, Hikaru; Yokoyama, Tetsuya; Koike, Tohru

    2005-03-15

    Imaging of a coimmobilized diaphorase and albumin surface was investigated by scanning electrochemical microscopy (SECM) with shear force based tip-substrate distance control. A microelectrode tip was attached to a commercially available tuning fork to detect the shear force between the microelectrode tip and the surface. We used the standing approach mode, which repeats an approach and retraction at each data point of the surface to obtain simultaneous current and topographic images. To check the performance of our SECM system, we imaged a platinum-patterned array electrode and a diaphorase/albumin coimmobilized glass surface. Since the system acquires current when the tip is retracted to a desired distance, this mode is useful for a relatively large microelectrode (approximately 10 microm) and for scanning a large area (few hundreds of micrometers). Furthermore, by retracting the tip when the tip moves laterally to the next data point to avoid contact between the tip and sample surface, we successfully imaged the surface without destroying its morphology. PMID:15762586

  19. Vegetation change (1988–2010 in Camdeboo National Park (South Africa, using fixed-point photo monitoring: The role of herbivory and climate

    Directory of Open Access Journals (Sweden)

    Mmoto L. Masubelele

    2013-02-01

    Full Text Available Fixed-point photo monitoring supplemented by animal census data and climate monitoring potential has never been explored as a long-term monitoring tool for studying vegetation change in the arid and semi-arid national parks of South Africa. The long-term (1988–2010, fixed-point monitoring dataset developed for the Camdeboo National Park, therefore, provides an important opportunity to do this. Using a quantitative estimate of the change in vegetation and growth form cover in 1152 fixed-point photographs, as well as series of step-point vegetation surveys at each photo monitoring site, this study documented the extent of vegetation change in the park in response to key climate drivers, such as rainfall, as well as land use drivers such as herbivory by indigenous ungulates. We demonstrated the varied response of vegetation cover within three main growth forms (grasses, dwarf shrubs [< 1 m] and tall shrubs [> 1 m] in three different vegetation units and landforms (slopes, plains, rivers within the Camdeboo National Park since 1988. Sites within Albany Thicket and Dwarf Shrublands showed the least change in vegetation cover, whilst Azonal vegetation and Grassy Dwarf Shrublands were more dynamic. Abiotic factors such as drought and flooding, total annual rainfall and rainfall seasonality appeared to have the greatest influence on growth form cover as assessed from the fixed-point photographs. Herbivory appeared not to have had a noticeable impact on the vegetation of the Camdeboo National Park as far as could be determined from the rather coarse approach used in this analysis and herbivore densities remained relatively low over the study duration.Conservation implications: We provided an historical assessment of the pattern of vegetation and climatic trends that can help evaluate many of South African National Parks’ biodiversity monitoring programmes, especially relating to habitat change. It will help arid parks in assessing the trajectories of

  20. Accurate 3D point cloud comparison and volumetric change analysis of Terrestrial Laser Scan data in a hard rock coastal cliff environment

    Science.gov (United States)

    Earlie, C. S.; Masselink, G.; Russell, P.; Shail, R.; Kingston, K.

    2013-12-01

    Our understanding of the evolution of hard rock coastlines is limited due to the episodic nature and ';slow' rate at which changes occur. High-resolution surveying techniques, such as Terrestrial Laser Scanning (TLS), have just begun to be adopted as a method of obtaining detailed point cloud data to monitor topographical changes over short periods of time (weeks to months). However, the difficulties involved in comparing consecutive point cloud data sets in a complex three-dimensional plane, such as occlusion due to surface roughness and positioning of data capture point as a result of a consistently changing environment (a beach profile), mean that comparing data sets can lead to errors in the region of 10 - 20 cm. Meshing techniques are often used for point cloud data analysis for simple surfaces, but in surfaces such as rocky cliff faces, this technique has been found to be ineffective. Recession rates of hard rock coastlines in the UK are typically determined using aerial photography or airborne LiDAR data, yet the detail of the important changes occurring to the cliff face and toe are missed using such techniques. In this study we apply an algorithm (M3C2 - Multiscale Model to Model Cloud Comparison), initially developed for analysing fluvial morphological change, that directly compares point to point cloud data using surface normals that are consistent with surface roughness and measure the change that occurs along the normal direction (Lague et al., 2013). The surfaces changes are analysed using a set of user defined scales based on surface roughness and registration error. Once the correct parameters are defined, the volumetric cliff face changes are calculated by integrating the mean distance between the point clouds. The analysis has been undertaken at two hard rock sites identified for their active erosion located on the UK's south west peninsular at Porthleven in south west Cornwall and Godrevy in north Cornwall. Alongside TLS point cloud data, in

  1. The effect of tip speed ratio on a vertical axis wind turbine at high Reynolds numbers

    Science.gov (United States)

    Parker, Colin M.; Leftwich, Megan C.

    2016-05-01

    This work visualizes the flow surrounding a scaled model vertical axis wind turbine at realistic operating conditions. The model closely matches geometric and dynamic properties—tip speed ratio and Reynolds number—of a full-size turbine. The flow is visualized using particle imaging velocimetry (PIV) in the midplane upstream, around, and after (up to 4 turbine diameters downstream) the turbine, as well as a vertical plane behind the turbine. Time-averaged results show an asymmetric wake behind the turbine, regardless of tip speed ratio, with a larger velocity deficit for a higher tip speed ratio. For the higher tip speed ratio, an area of averaged flow reversal is present with a maximum reverse flow of -0.04U_∞. Phase-averaged vorticity fields—achieved by syncing the PIV system with the rotation of the turbine—show distinct structures form from each turbine blade. There were distinct differences in results by tip speed ratios of 0.9, 1.3, and 2.2 of when in the cycle structures are shed into the wake—switching from two pairs to a single pair of vortices being shed—and how they convect into the wake—the middle tip speed ratio vortices convect downstream inside the wake, while the high tip speed ratio pair is shed into the shear layer of the wake. Finally, results show that the wake structure is much more sensitive to changes in tip speed ratio than to changes in Reynolds number.

  2. Nose Tip Region Detection in 3D Facial Model across Large Pose Variation and Facial Expression

    OpenAIRE

    Laili Hayati Anuar; Syamsiah Mashohor; Makhfudzah Mokhtar; Wan Azizun Wan Adnan

    2010-01-01

    Detecting nose tip location has become an important task in face analysis. However, for a 3D face model with presence of large rotation variation, detecting nose tip location is certainly a challenging task. In this paper, we propose a method to detect nose tip region in large rotation variation based on the geometrical shape of a nose. Nose region has always been considered as the most protuberant part of a face. Based on convex points of face surface, we use morphological approach to obtain...

  3. The branching Brownian motion seen from its tip

    CERN Document Server

    Aïdékon, E; Brunet, É; Shi, Z

    2011-01-01

    Very recently, Arguin et al. have proved the conjecture (which can be found in the work of Lalley and Sellke) that the branching Brownian motion seen from its tip (e.g. from its rightmost particle) converges to an invariant point process. The main goal of the present work is to give a complete description of the limit object and an alternative proof of the convergence. As conjectured by Brunet and Derrida and proved by Arguin et al., the structure of this extremal point process turns out to be a certain Poisson point process with exponential intensity in which each atom has been decorated by an independent copy of an auxiliary point process. Here, we give an explicit construction of this decoration point process.

  4. SRGM with logistic-exponential testing-effort with change-point and Analysis of Optimal release policies based on increasing the test efficiency

    Directory of Open Access Journals (Sweden)

    Dr.K.Nageswara Rao

    2010-05-01

    Full Text Available Reliability is the one of the important factor of software quality. Past few decades several software reliability growth models are proposed to access the quality of the software. Main challenging task of reliability growth model is predicting the reliability, totalcost at optimal time at, software released into the market. It has been observed that most of the reliability growth models predict the failure rate to be constant during the software testing, but in reality software failure rate changes with testing time. In this paper we have investigated software reliability growth model byincorporating the both change point and testing effort. We incorporated logistic-exponential TEF in software reliability growth model with change-point. We also investigated the how testing efficiency can be increased by adopting the new automated testing tools into the software testing and its effect on the total cost of the software. Experiments are done on real datasets. Parameters are estimated. Results show the better fit.

  5. Analytical description of brittle-to-ductile transition in bcc metals. Nucleation of dislocation loop at the crack tip

    International Nuclear Information System (INIS)

    Nucleation of dislocation loop at the crack tip in a material subjected to uniaxial loading is investigated. Analytical expression for the total energy of rectangular dislocation loop at the crack tip is found. Dependence of the nucleation energy barrier on dislocation loop shape and stress intensity factor at the crack tip is determined. It is established that the energetic barrier for nucleation of dislocation loop strongly depends on the stress intensity factor. Nucleation of dislocation loop is very sensitive to stress field modifiers (forest dislocations, precipitates, clusters of point defects, etc) in the crack tip vicinity. (orig.)

  6. The Nature of Scientific Revolutions from the Vantage Point of Chaos Theory: Toward a Formal Model of Scientific Change

    Science.gov (United States)

    Perla, Rocco J.; Carifio, James

    2005-01-01

    In sharp contrast to the early positivist view of the nature of science and scientific knowledge, Kuhn argues that the scientific enterprise involves states of continuous, gradual development punctuated by comparatively rare instances of turmoil and change, which ultimately brings about a new stability and a qualitatively changed knowledge base.…

  7. Investigation of a Centrifugal Compressor and Study of the Area Ratio and TIP Clearance Effects on Performance

    Institute of Scientific and Technical Information of China (English)

    Mahdi Nili-Ahmadabadi; Ali Hajilouy-Benisi; Mohammad Durali; Farhad Ghadak

    2008-01-01

    In this research, the centrifugal compressor of a turbocharger is investigated experimentally and numerically. Performance characteristics of the compressor were obtained experimentally by measurements of rotor speed and flow parameters at the inlet and outlet of the compressor. Three dimensional flow field in the impeller and dif-fuser was analyzed numerically using a full Navier-Stokes program with SST turbulence model. The performance characteristics of the compressor were obtained numerically, which were then compared with the experimental results. The comparison shows good agreement.Furthermore, the effect of area ratio and tip clearance on the performance parameters and flow field was stud-ied numerically. The impeller area ratio was changed by cutting the impeller exit axial width from an initial value of 4.1 mm to a final value of 5.1 mm, resulting in an area ratio from 0.792 to 0.965. For the rotor with exit axial width of 4.6 nun, performance was investigated for tip clearance of 0.0, 0.5 and 1.0 mm. Results of this simula-tion at design point showed that the compressor pressure ratio peaked at an area ratio of 0.792 while the effi-ciency peaked at a higher value of area ratio of 0.878. Also the increment of the tip clearance from 0 to 1 mm re-sulted in 20 percent efficiency decrease.

  8. Investigation of a centrifugal compressor and study of the area ratio and TIP clearance effects on performance

    Science.gov (United States)

    Nili-Ahmadabadi, Mahdi; Hajilouy-Benisi, Ali; Durali, Mohammad; Ghadak, Farhad

    2008-12-01

    In this research, the centrifugal compressor of a turbocharger is investigated experimentally and numerically. Performance characteristics of the compressor were obtained experimentally by measurements of rotor speed and flow parameters at the inlet and outlet of the compressor. Three dimensional flow field in the impeller and diffuser was analyzed numerically using a full Navier-Stokes program with SST turbulence model. The performance characteristics of the compressor were obtained numerically, which were then compared with the experimental results. The comparison shows good agreement. Furthermore, the effect of area ratio and tip clearance on the performance parameters and flow field was studied numerically. The impeller area ratio was changed by cutting the impeller exit axial width from an initial value of 4.1 mm to a final value of 5.1 mm, resulting in an area ratio from 0.792 to 0.965. For the rotor with exit axial width of 4.6 mm, performance was investigated for tip clearance of 0.0, 0.5 and 1.0 mm. Results of this simulation at design point showed that the compressor pressure ratio peaked at an area ratio of 0.792 while the efficiency peaked at a higher value of area ratio of 0.878. Also the increment of the tip clearance from 0 to 1 mm resulted in 20 percent efficiency decrease.

  9. Changing Frequency Separation of Kilohertz Quasi-Periodic Oscillations in the Sonic-Point Beat-Frequency Model

    CERN Document Server

    Lamb, F K; Lamb, Frederick K.

    2000-01-01

    Previous work on the sonic-point beat-frequency (SPBF) model of the kilohertz quasi-periodic oscillations (QPOs) observed in the X-ray flux from neutron stars in low-mass binary systems has shown that it naturally explains many properties of these QPOs. These include the existence of just two principal QPOs in a given source, the commensurability of the frequency separation \\Dnu\\ of the two kilohertz QPOs and the spin frequency \

  10. Change Point in Panel Data with Small Fixed Panel Size: Ratio and Non-Ratio Test Statistics

    OpenAIRE

    Peštová, Barbora; Pešta, Michal

    2016-01-01

    The main goal is to develop and, consequently, compare stochastic methods for detection whether a structural change in panel data occurred at some unknown time or not. Panel data of our interest consist of a moderate or relatively large number of panels, while the panels contain a small number of observations. Testing procedures to detect a possible common change in means of the panels are established. Ratio and non-ratio type test statistics are considered. Their asymptotic distributions und...

  11. Texas Intense Positron Source (TIPS)

    Science.gov (United States)

    O'Kelly, D.

    2003-03-01

    The Texas Intense Positron Source (TIPS) is a state of the art variable energy positron beam under construction at the Nuclear Engineering Teaching Laboratory (NETL). Projected intensities on the order of the order of 10^7 e+/second using ^64Cu as the positron source are expected. Owing to is short half-life (t1/2 12.8 hrs), plans are to produce the ^64Cu isotope on-site using beam port 1 of NETL TRIGA Mark II reactor. Following tungsten moderation, the positrons will be electrostatically focused and accelerated from few 10's of eV up to 30 keV. This intensity and energy range should allow routine performance of several analytical techniques of interest to surface scientists (PALS, PADB and perhaps PAES and LEPD.) The TIPS project is being developed in parallel phases. Phase I of the project entails construction of the vacuum system, source chamber, main beam line, electrostatic/magnetic focusing and transport system as well as moderator design. Initial construction, testing and characterization of moderator and beam transport elements are underway and will use a commercially available 10 mCi ^22Na radioisotope as a source of positrons. Phase II of the project is concerned primarily with the Cu source geometry and thermal properties as well as production and physical handling of the radioisotope. Additional instrument optimizing based upon experience gained during Phase I will be incorporated in the final design. Current progress of both phases will be presented along with motivations and future directions.

  12. Smart helicopter rotor with active blade tips

    Science.gov (United States)

    Bernhard, Andreas Paul Friedrich

    2000-10-01

    The smart active blade tip (SABT) rotor is an on-blade rotor vibration reduction system, incorporating active blade tips that can be independently pitched with respect to the main blade. The active blade tip rotor development included an experimental test program culminating in a Mach scale hover test, and a parallel development of a coupled, elastic actuator and rotor blade analysis for preliminary design studies and hover performance prediction. The experimental testing focussed on a small scale rotor on a bearingless Bell-412 hub. The fabricated Mach-scale active-tip rotor has a diameter of 1.524 m, a blade chord of 76.2 mm and incorporated a 10% span active tip. The nominal operating speed is 2000 rpm, giving a tip Mach number of 0.47. The blade tips are driven by a novel piezo-induced bending-torsion coupled actuator beam, located spanwise in the hollow mid-cell of the main rotor blade. In hover at 2000 rpm, at 2 deg collective, and for an actuation of 125 Vrms, the measured blade tip deflection at the first four rotor harmonics is between +/-1.7 and +/-2.8 deg, increasing to +/-5.3 deg at 5/rev with resonant amplification. The corresponding oscillatory amplitude of the rotor thrust coefficient is between 0.7 · 10-3 and 1.3 · 10-1 at the first four rotor harmonics, increasing to 2.1 · 10-3 at 5/rev. In general, the experimental blade tip frequency response and corresponding rotor thrust response are well captured by the analysis. The flexbeam root flap bending moment is predicted in trend, but is significantly over-estimated. The blade tips did not deflect as expected at high collective settings, because of the blade tip shaft locking up in the bearing. This is caused by the high flap bending moment on the blade tip shaft. Redesign of the blade tip shaft assembly and bearing support is identified as the primary design improvement for future research. The active blade tip rotor was also used as a testbed for the evaluation of an adaptive neural-network based

  13. Predicting Binding Free Energy Change Caused by Point Mutations with Knowledge-Modified MM/PBSA Method.

    Directory of Open Access Journals (Sweden)

    Marharyta Petukh

    2015-07-01

    Full Text Available A new methodology termed Single Amino Acid Mutation based change in Binding free Energy (SAAMBE was developed to predict the changes of the binding free energy caused by mutations. The method utilizes 3D structures of the corresponding protein-protein complexes and takes advantage of both approaches: sequence- and structure-based methods. The method has two components: a MM/PBSA-based component, and an additional set of statistical terms delivered from statistical investigation of physico-chemical properties of protein complexes. While the approach is rigid body approach and does not explicitly consider plausible conformational changes caused by the binding, the effect of conformational changes, including changes away from binding interface, on electrostatics are mimicked with amino acid specific dielectric constants. This provides significant improvement of SAAMBE predictions as indicated by better match against experimentally determined binding free energy changes over 1300 mutations in 43 proteins. The final benchmarking resulted in a very good agreement with experimental data (correlation coefficient 0.624 while the algorithm being fast enough to allow for large-scale calculations (the average time is less than a minute per mutation.

  14. Sensitivity of several selected mechanical properties of moso bamboo to moisture content change under the fibre saturation point

    Directory of Open Access Journals (Sweden)

    Zehui Jiang

    2012-11-01

    Full Text Available The moisture dependence of different mechanical properties of bamboo has not been fully understood. In this work, the longitudinal tensile modulus, bending modulus, and compressive and shearing strength parallel to the grain were determined for bamboo of ages 0.5, 1.5, 2.5, and 4.5 years under different moisture contents (MC to elucidate the sensitivity of different mechanical properties of bamboo to MC change. The results showed that the four mechanical properties of bamboo respond differently to MC changes. Compressive and shearing strength parallel to the grain were most sensitive to MC changes, followed by longitudinal tensile modulus, then bending modulus. This can be partially explained by the different responses of the three main components in the plant cell wall to MC change. For tensile modulus and bending modulus, the effect of bamboo age on the sensitivity to MC change was insignificant, while young bamboo (0.5 years old was more sensitive to MC changes for shear strength and less sensitive for compression strength than older bamboo.

  15. CFD analysis of cloud cavitation on three tip-modified propellers with systematically varied tip geometry

    DEFF Research Database (Denmark)

    Shin, K. W.; Andersen, P.

    2015-01-01

    The blade tip loading is often reduced as an effort to restrain sheet and tip vortex cavitation in the design of marine propellers. This CFD analysis demonstrates that an excessive reduction of the tip loading can cause cloud cavitation responsible for much of noise and surface erosion. Detached ...

  16. Tip-induced gating of molecular levels in carbene-based junctions.

    Science.gov (United States)

    Foti, Giuseppe; Vázquez, Héctor

    2016-03-29

    We study the conductance of N-heterocyclic carbene-based (NHC) molecules on gold by means of first-principles calculations based on density-functional theory and non-equilibrium Green's functions. We consider several tip structures and find a strong dependence of the position of the NHC molecular levels with the atomistic structure of the tip. The position of the lowest unoccupied molecular orbital (LUMO) can change by almost 0.8 eV with tip shape. Through an analysis of the net charge transfer, electron redistribution and work function for each tip structure, we rationalize the LUMO shifts in terms of the sum of the work function and the maximum electrostatic potential arising from charge rearrangement. These differences in the LUMO position, effectively gating the molecular levels, result in large conductance variations. These findings open the way to modulating the conductance of NHC-based molecular circuits through the controlled design of the tip atomistic structure. PMID:26891059

  17. Modeling halotropism: a key role for root tip architecture and reflux loop remodeling in redistributing auxin

    Science.gov (United States)

    van den Berg, Thea; Korver, Ruud A.; Testerink, Christa

    2016-01-01

    A key characteristic of plant development is its plasticity in response to various and dynamically changing environmental conditions. Tropisms contribute to this flexibility by allowing plant organs to grow from or towards environmental cues. Halotropism is a recently described tropism in which plant roots bend away from salt. During halotropism, as in most other tropisms, directional growth is generated through an asymmetric auxin distribution that generates differences in growth rate and hence induces bending. Here, we develop a detailed model of auxin transport in the Arabidopsis root tip and combine this with experiments to investigate the processes generating auxin asymmetry during halotropism. Our model points to the key role of root tip architecture in allowing the decrease in PIN2 at the salt-exposed side of the root to result in a re-routing of auxin to the opposite side. In addition, our model demonstrates how feedback of auxin on the auxin transporter AUX1 amplifies this auxin asymmetry, while a salt-induced transient increase in PIN1 levels increases the speed at which this occurs. Using AUX1-GFP imaging and pin1 mutants, we experimentally confirmed these model predictions, thus expanding our knowledge of the cellular basis of halotropism. PMID:27510970

  18. Modeling halotropism: a key role for root tip architecture and reflux loop remodeling in redistributing auxin.

    Science.gov (United States)

    van den Berg, Thea; Korver, Ruud A; Testerink, Christa; Ten Tusscher, Kirsten H W J

    2016-09-15

    A key characteristic of plant development is its plasticity in response to various and dynamically changing environmental conditions. Tropisms contribute to this flexibility by allowing plant organs to grow from or towards environmental cues. Halotropism is a recently described tropism in which plant roots bend away from salt. During halotropism, as in most other tropisms, directional growth is generated through an asymmetric auxin distribution that generates differences in growth rate and hence induces bending. Here, we develop a detailed model of auxin transport in the Arabidopsis root tip and combine this with experiments to investigate the processes generating auxin asymmetry during halotropism. Our model points to the key role of root tip architecture in allowing the decrease in PIN2 at the salt-exposed side of the root to result in a re-routing of auxin to the opposite side. In addition, our model demonstrates how feedback of auxin on the auxin transporter AUX1 amplifies this auxin asymmetry, while a salt-induced transient increase in PIN1 levels increases the speed at which this occurs. Using AUX1-GFP imaging and pin1 mutants, we experimentally confirmed these model predictions, thus expanding our knowledge of the cellular basis of halotropism. PMID:27510970

  19. Two-dimensional phase changes of nitric oxide adsorbed on lamellar halides. Two-dimensional triple points

    International Nuclear Information System (INIS)

    Adsorption isotherms of nitric oxide on the cleavage face of fourteen lamellar halides (NiCl2, CoCl2, FeCl2, NiBr2, CoBr2, FeBr2, MgBr2, CdCl2, Col2, CdBr2, MnI2, CdI2, CaI2 and PbI2) have been determined. Adsorbents having a uniform surface have been prepared by sublimation in a rapid current of dry nitrogen. The isotherms show vertical steps corresponding to two-dimensional phase transitions. Except for CaI2, a crystalline monomolecular layer β constituted of dimers oriented perpendicularly to the surface of the substrate, is formed. At low temperatures this phase is formed directly during a two-dimensional condensation. Above the temperature of a two-dimensional triple point, a crystalline layer α, where the dimers lie flat on the surface, appears as an intermediate phase. The variations of the two-dimensional triple point temperature and of the free energy of the β phase with the nature and the crystal parameter of the adsorbent are explained

  20. A Custom——Leaving a Tip

    Institute of Scientific and Technical Information of China (English)

    张宗友

    2005-01-01

    Leaving a tip in a restaurant has become a custom in most countries. The word “tip” came from the Latin word “Gratis”, meaning free. Tips are defined as small gifts of money for service in addition to the payment due.

  1. Change in the radiation dose at a point where an inhomogeneity partly covers the radiation field from a 60Co-γ-source

    International Nuclear Information System (INIS)

    Measurements and calculations have been made in order to study the change of the radiation dose in a point when an inhomogeneity covers parts of the radiation field from a Co 60-source. An ionization chamber, placed in a water phantom, was used for the measurements. As inhomogeneity an air cavity was used. The measuring point was placed on the central axis of the radiation field during the measurement. The air cavity was moved in front of the measuring point 0.5 - 1 cm by steps laterally, i.e. along a line perpendicular to the radiation direction. Measurements were made at different depths behind the air cavity. The air cavity was placed at different distances from the front plate of the water phantom. Measurements and calculations show that the change of the radiation dose, when the edge of the air cavity passes the measuring point, varies with the depth distance to the air cavity. The greatest deviation is near the air cavity and at a great distance behind this. The change of the radiation dose is less than 2 percent at distances greater than 2 cm from the edge of the air cavity laterally. This change is independent of the depth distance to the air cavity. The maximum deviation 1 cm from the edge of the air cavity is 5 percent independent of the distance tothe air cavity. Used methods of calculation can be extended to be used for irregular inhomogeneities but this requires knowledge of the three-dimensional extension of the inhomogeneity. (M.S.)

  2. Participatory action research (PAR) as an entry point for supporting climate change adaptation by smallholder farmers in Africa

    NARCIS (Netherlands)

    Mapfumo, P.; Adjei-Nsiah, S.; Mtambanengwe, F.; Chikowo, R.; Giller, K.E.

    2013-01-01

    Emerging trends of a changing and increasingly variable climate have introduced new livelihood challenges in rain-fed smallholder agricultural systems that predominate in Sub-Saharan Africa (SSA). The capacity of local farming communities and their institutions to respond to the new and emerging imp

  3. GA_INTERSECTS - Transect-Shoreline Intersection Points for Georgia Atlantic Coast Generated to Calculate Shoreline Change Rates

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Rates of long-term and short-term shoreline change were generated in a GIS with the Digital Shoreline Analysis System (DSAS) version 2.0, an ArcView extension...

  4. FL_INTERSECTS - Transect-Shoreline Intersection Points for Florida Atlantic Coast Generated to Calculate Shoreline Change Rates

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Rates of long-term and short-term shoreline change were generated in a GIS with the Digital Shoreline Analysis System (DSAS) version 2.0, an ArcView extension...

  5. NC_INTERSECTS - Transect-Shoreline Intersection Points for North Carolina Atlantic Coast Generated to Calculate Shoreline Change Rates

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Rates of long-term and short-term shoreline change were generated in a GIS with the Digital Shoreline Analysis System (DSAS) version 2.0, an ArcView extension...

  6. SC_INTERSECTS - Transect-Shoreline Intersection Points for South Carolina Atlantic Coast Generated to Calculate Shoreline Change Rates

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Rates of long-term and short-term shoreline change were generated in a GIS with the Digital Shoreline Analysis System (DSAS) version 2.0, an ArcView extension...

  7. Predicting responses of the Adélie penguin population of Edmonson Point to future sea ice changes in the Ross Sea

    Directory of Open Access Journals (Sweden)

    Tosca eBallerini

    2015-02-01

    Full Text Available Atmosphere-Ocean General Circulation Models (AOGCMs predict changes in the sea ice environment and in atmospheric precipitations over larger areas of Antarctica. These changes are expected to affect the population dynamics of seabirds and marine mammals, but the extent of this influence is not clear. We investigated the future population trajectories of the colony of Adélie penguins at Edmonson Point, in the Ross Sea, from 2010 to 2100. To do so, we incorporated the relationship between sea ice and demographic parameters of the studied colony into a matrix population model. Specifically, we used sea ice projections from AOGCMs and a proxy for snowfall precipitation. Simulations of population persistence under future climate change scenarios showed that a reduction in sea ice extent and an increase in precipitation events during the breeding season will drive the population to extinction. However, the population growth rate estimated by the model was lower than the population growth rate observed during the last decades, suggesting that recruits from other colonies maintain the observed population dynamics at Edmonson Point. This local ‘rescue’ effect is consistent with a metapopulation dynamic for Adélie penguins in the Ross Sea, in which neighboring colonies might exhibit contrasting population trends and different density-dependent effects. In the hypothesis that connectivity with larger source colonies or that local recruitment would decrease, the sink colony at Edmonson Point is predicted to disappear.

  8. Developmental changes in emotion recognition from full-light and point-light displays of body movement.

    Directory of Open Access Journals (Sweden)

    Patrick D Ross

    Full Text Available To date, research on the development of emotion recognition has been dominated by studies on facial expression interpretation; very little is known about children's ability to recognize affective meaning from body movements. In the present study, we acquired simultaneous video and motion capture recordings of two actors portraying four basic emotions (Happiness Sadness, Fear and Anger. One hundred and seven primary and secondary school children (aged 4-17 and 14 adult volunteers participated in the study. Each participant viewed the full-light and point-light video clips and was asked to make a forced-choice as to which emotion was being portrayed. As a group, children performed worse than adults for both point-light and full-light conditions. Linear regression showed that both age and lighting condition were significant predictors of performance in children. Using piecewise regression, we found that a bilinear model with a steep improvement in performance until 8.5 years of age, followed by a much slower improvement rate through late childhood and adolescence best explained the data. These findings confirm that, like for facial expression, adolescents' recognition of basic emotions from body language is not fully mature and seems to follow a non-linear development. This is in line with observations of non-linear developmental trajectories for different aspects of human stimuli processing (voices and faces, perhaps suggesting a shift from one perceptual or cognitive strategy to another during adolescence. These results have important implications to understanding the maturation of social cognition.

  9. Neighborhood Chance and Neighborhood Change

    CERN Document Server

    Van de Rijt, Arnout; Macy, Michael

    2008-01-01

    Schelling showed how residential segregation can arise even in a population that is tolerant of diversity. Bruch and Mare challenge this conclusion, claiming that it depends on threshold preference functions that are not empirically plausible. When they increased sensitivity to small changes in ethnic composition, using both linear and empirical preference functions, segregation largely disappeared. They conclude that tipping at the population level (into segregation) depends on tipping at the individual level (a critical point above and below which the individual is indifferent). However, when we replicated their model, we discovered that the results they report for both linear and empirical preferences were incorrect. We found that sensitivity to change can lead to integration in an ethnocentric population that prefers in-group neighbors, but only if ethnic preferences are sufficiently weak relative to chance. When ethnic preferences are sufficiently strong, segregation is greater with linear than with thre...

  10. Predicting Binding Free Energy Change Caused by Point Mutations with Knowledge-Modified MM/PBSA Method

    OpenAIRE

    Marharyta Petukh; Minghui Li; Emil Alexov

    2015-01-01

    Author Summary Developing methods for accurate prediction of effects of amino acid substitutions on protein-protein affinity is important for both understanding disease-causing mechanism of missense mutations and guiding protein engineering. For both purposes, there is a need for accurate methods primarily based on first principle calculations, while being fast enough to handle large number of cases. Here we report a new method, the Single Amino Acid Mutation based change in Binding free Ener...

  11. Results of Cervical Recapping Laminoplasty: Gross Anatomical Changes, Biomechanical Evaluation at Different Time Points and Degrees of Level Involvement

    OpenAIRE

    Yu Si; Zhenyu Wang; Tao Yu; Guo zhong Lin; Jia Zhang; Kuo Zhang; Hua Zhang; Yuan chao Li

    2014-01-01

    BACKGROUND: Recapping laminoplasty has become the frequently-used approach to the spinal canal when bone decompression of the vertebral canal is not the goal. However, what changes will occur after surgery, and whether recapping laminoplasty can actually reduce the risk of delayed deformities remains unknown. METHODOLOGY: We designed an animal experiment using a caprine model, and partitioned the animals into in vitro and in vivo surgical groups. We performed recapping laminoplasty on one gro...

  12. Field emission study of CNTs on metal tips

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The field emission characteristics of multiwalled carbon nanotubes grown on metal tips are studied at various temperatures.It is found that emission current at a given applied electric field increased with the temperature,and the stability of the current did not change.The dependence upon temperature varies quite differently with the metal substrates.This may result from the asymmetry of the CNTs and the interface effect between CNT and underlay.

  13. Electrochemical Tip-Enhanced Raman Spectroscopy.

    Science.gov (United States)

    Zeng, Zhi-Cong; Huang, Sheng-Chao; Wu, De-Yin; Meng, Ling-Yan; Li, Mao-Hua; Huang, Teng-Xiang; Zhong, Jin-Hui; Wang, Xiang; Yang, Zhi-Lin; Ren, Bin

    2015-09-23

    Interfacial properties are highly important to the performance of some energy-related systems. The in-depth understanding of the interface requires highly sensitive in situ techniques that can provide fingerprint molecular information at nanometer resolution. We developed an electrochemical tip-enhanced Raman spectroscopy (EC-TERS) by introduction of the light horizontally to the EC-STM cell to minimize the optical distortion and to keep the TERS measurement under a well-controlled condition. We obtained potential-dependent EC-TERS from the adsorbed aromatic molecule on a Au(111) surface and observed a substantial change in the molecule configuration with potential as a result of the protonation and deprotonation of the molecule. Such a change was not observable in EC-SERS (surface-enhanced), indicating EC-TERS can more faithfully reflect the fine interfacial structure than EC-SERS. This work will open a new era for using EC-TERS as an important nanospectroscopy tool for the molecular level and nanoscale analysis of some important electrochemical systems including solar cells, lithium ion batteries, fuel cells, and corrosion. PMID:26351986

  14. The African Origin of Complex Projectile Technology: An Analysis Using Tip Cross-Sectional Area and Perimeter

    OpenAIRE

    Shea, John J.; Matthew L. Sisk

    2011-01-01

    Despite a body of literature focusing on the functionality of modern and stylistically distinct projectile points, comparatively little attention has been paid to quantifying the functionality of the early stages of projectile use. Previous work identified a simple ballistics measure, the Tip Cross-Sectional Area, as a way of determining if a given class of stone points could have served as effective projectile armatures. Here we use this in combination with an alternate measure, the Tip Cros...

  15. Source to point of use drinking water changes and knowledge, attitude and practices in Katsina State, Northern Nigeria

    Science.gov (United States)

    Onabolu, B.; Jimoh, O. D.; Igboro, S. B.; Sridhar, M. K. C.; Onyilo, G.; Gege, A.; Ilya, R.

    In many Sub-Saharan countries such as Nigeria, inadequate access to safe drinking water is a serious problem with 37% in the region and 58% of rural Nigeria using unimproved sources. The global challenge to measuring household water quality as a determinant of safety is further compounded in Nigeria by the possibility of deterioration from source to point of use. This is associated with the use of decentralised water supply systems in rural areas which are not fully reticulated to the household taps, creating a need for an integrated water quality monitoring system. As an initial step towards establishing the system in the north west and north central zones of Nigeria, The Katsina State Rural Water and Sanitation Agency, responsible for ensuring access to safe water and adequate sanitation to about 6 million people carried out a three pronged study with the support of UNICEF Nigeria. Part 1 was an assessment of the legislative and policy framework, institutional arrangements and capacity for drinking water quality monitoring through desk top reviews and Key Informant Interviews (KII) to ascertain the institutional capacity requirements for developing the water quality monitoring system. Part II was a water quality study in 700 households of 23 communities in four local government areas. The objectives were to assess the safety of drinking water, compare the safety at source and household level and assess the possible contributory role of end users’ Knowledge Attitudes and Practices. These were achieved through water analysis, household water quality tracking, KII and questionnaires. Part III was the production of a visual documentary as an advocacy tool to increase awareness of the policy makers of the linkages between source management, treatment and end user water quality. The results indicate that except for pH, conductivity and manganese, the improved water sources were safe at source. However there was a deterioration in water quality between source and

  16. Attached cavitation at a small diameter ultrasonic horn tip

    Science.gov (United States)

    Žnidarčič, Anton; Mettin, Robert; Cairós, Carlos; Dular, Matevž

    2014-02-01

    Ultrasonic horn transducers are frequently used in applications of acoustic cavitation in liquids, for instance, for cell disruption or sonochemical reactions. They are operated typically in the frequency range up to about 50 kHz and have tip diameters from some mm to several cm. It has been observed that if the horn tip is sufficiently small and driven at high amplitude, cavitation is very strong, and the tip can be covered entirely by the gas/vapor phase for longer time intervals. A peculiar dynamics of the attached cavity can emerge with expansion and collapse at a self-generated frequency in the subharmonic range, i.e., below the acoustic driving frequency. Here, we present a systematic study of the cavitation dynamics in water at a 20 kHz horn tip of 3 mm diameter. The system was investigated by high-speed imaging with simultaneous recording of the acoustic emissions. Measurements were performed under variation of acoustic power, air saturation, viscosity, surface tension, and temperature of the liquid. Our findings show that the liquid properties play no significant role in the dynamics of the attached cavitation at the small ultrasonic horn. Also the variation of the experimental geometry, within a certain range, did not change the dynamics. We believe that the main two reasons for the peculiar dynamics of cavitation on a small ultrasonic horn are the higher energy density on a small tip and the inability of the big tip to "wash" away the gaseous bubbles. Calculation of the somewhat adapted Strouhal number revealed that, similar to the hydrodynamic cavitation, values which are relatively low characterize slow cavitation structure dynamics. In cases where the cavitation follows the driving frequency this value lies much higher - probably at Str > 20. In the spirit to distinguish the observed phenomenon with other cavitation dynamics at ultrasonic transducer surfaces, we suggest to term the observed phenomenon of attached cavities partly covering the full horn

  17. PowerPoint 2013 bible

    CERN Document Server

    Wempen, Faithe

    2013-01-01

    Master PowerPoint and improve your presentation skills with one book! In today's business climate, you need to know PowerPoint inside and out, and that's not all. You also need to be able to make a presentation that makes an impact. From using sophisticated transitions and animation in your PowerPoint presentations to interfacing in person with your audience, this information-packed book helps you succeed. Start creating professional-quality slides that captivate audiences and discover essential tips and techniques for making first-rate presentations, whether you're at a podium or

  18. Fatigue-Induced Changes in Movement Pattern and Muscle Activity During Ballet Releve on Demi-Pointe.

    Science.gov (United States)

    Lin, Cheng-Feng; Lee, Wan-Chin; Chen, Yi-An; Hsue, Bih-Jen

    2016-08-01

    Fatigue in ballet dancers may lead to injury, particularly in the lower extremities. However, few studies have investigated the effects of fatigue on ballet dancers' performance and movement patterns. Thus, the current study examines the effect of fatigue on the balance, movement pattern, and muscle activities of the lower extremities in ballet dancers. Twenty healthy, female ballet dancers performed releve on demi-pointe before and after fatigue. The trajectory of the whole body movement and the muscle activities of the major lower extremity muscles were recorded continuously during task performance. The results show that fatigue increases the medial-lateral center of mass (COM) displacement and hip and trunk motion, but decreases the COM velocity and ankle motion. Moreover, fatigue reduces the activities of the hamstrings and tibialis anterior, but increases that of the soleus. Finally, greater proximal hip and trunk motions are applied to compensate for the effects of fatigue, leading to a greater COM movement. Overall, the present findings show that fatigue results in impaired movement control and may therefore increase the risk of dance injury. PMID:27622498

  19. Results of cervical recapping laminoplasty: gross anatomical changes, biomechanical evaluation at different time points and degrees of level involvement.

    Directory of Open Access Journals (Sweden)

    Yu Si

    Full Text Available BACKGROUND: Recapping laminoplasty has become the frequently-used approach to the spinal canal when bone decompression of the vertebral canal is not the goal. However, what changes will occur after surgery, and whether recapping laminoplasty can actually reduce the risk of delayed deformities remains unknown. METHODOLOGY: We designed an animal experiment using a caprine model, and partitioned the animals into in vitro and in vivo surgical groups. We performed recapping laminoplasty on one group and laminectomy on another group. These animals were sacrificed six months after operating, cervical spines removed, biomechanically tested, and these data were compared to determine whether the recapping laminoplasty technique leads to subsequent differences in range of motion. Image data were also obtained before the surgery and when the animals were killed. Besides, we investigated the initial differences in kinetics between recapping laminoplasty and laminectomy. We did this by comparing data obtained from biomechanical testing of in vitro-performed recapping laminoplasty and laminectomy. Finally, we investigated the effect that longitudinal distance has on cervical mechanics. This was determined by performing a two-level recapping laminoplasty, and then extending the laminoplasty to the next level and repeating the mechanical testing at each step. PRINCIPAL FINDINGS: There were three mainly morphological changes at the six months after laminoplasty: volume reduction and bone nonunion of the recapping laminae, irregular fibrosis formation around the facet joints and re-implanted lamina-ligamentous complex. In the biomechanical test, comparing with laminectomy, recapping laminoplasty didn't show significant differences in the immediate postoperative comparison, while recapping laminoplasty demonstrated significantly decreased motion in flexion/extension six months later. Inclusion of additional levels in the laminotomy procedure didn't lead to changes

  20. Changes in the zero point energy of the protons as the source of the binding energy of water to A phase DNA

    CERN Document Server

    Reiter, G F; Mayers, J

    2010-01-01

    The zero point kinetic energy of protons in water is large on the scale of chemical interaction energies(29 Kj/mol in bulk room temperature water). Its value depends upon the structure of the hydrogen bond network, and can change as the network is confined or as water interacts with surfaces. These changes have been observed to be large on a chemical scale for water confined in carbon nanotubes and in the pores of xerogel, and may play a fundamental, and neglected, role in biological processes involving confined water. We measure the average momentum distribution of the protons in salmon Na-DNA using Deep Inelastic Neutron Scattering, for a weakly hydrated (6w/bp) and a dehydrated fiber sample. This permits the determination of the change in total kinetic energy of the system per water molecule removed from the DNA and placed in the bulk liquid. This energy is equal, within errors, to the measured enthalpy for the same process, demonstrating that changes in the zero point motion of the protons, arising from c...

  1. Conservative and dissipative tip-sample interaction forces probed with dynamic AFM

    Science.gov (United States)

    Gotsmann, B.; Seidel, C.; Anczykowski, B.; Fuchs, H.

    1999-10-01

    The conservative and dissipative forces between tip and sample of a dynamic atomic force microscopy (AFM) were investigated using a combination of computer simulations and experimental AFM data obtained by the frequency modulation technique. In this way it became possible to reconstruct complete force versus distance curves and damping coefficient versus distance curves from experimental data without using fit parameters for the interaction force and without using analytical interaction models. A comparison with analytical approaches is given and a way to determine a damping coefficient curve from experimental data is proposed. The results include the determination of the first point of repulsive contact of a vibrating tip when approaching a sample. The capability of quantifying the tip-sample interaction is demonstrated using experimental data obtained with a silicon tip and a mica sample in UHV.

  2. Scintigraphic evaluation of hepatic blood flow after intrahepatic portosystemic shunt (TIPS)

    Energy Technology Data Exchange (ETDEWEB)

    Menzel, J. [Department of Medicine B, University of Muenster, Muenster (Germany); Schober, O. [Department of Nuclear Medicine, University of Muenster, Muenster (Germany); Reimer, P. [Department of Radiology, University of Muenster, Muenster (Germany); Domschke, W. [Department of Medicine B, University of Muenster, Muenster (Germany)

    1997-06-10

    In patients with liver cirrhosis a transjugularly placed intrahepatic portocaval shunt (TIPS) is a non-surgical portosystemic device which aims to reduce portal venous pressure. In comparison with Doppler sonography, we evaluated in 28 patients the diagnostic impact of liver perfusion scintigraphy (with technetium-99m diethylene triamine penta-acetic acid) in the assessment of changes in the hepatic blood flow after TIPS shunting. The arterial and portal contributions to hepatic flow were calculated from the areas under the biphasic time-activity curve. In the course of TIPS shunting, patency is threatened by reocclusion. Angiography is the gold standard for TIPS shunt reassessment. However, there is a need for a less invasive diagnostic procedure, such as scintigraphy or Doppler sonography, for the early detection of shunt insufficiency. Scintigraphy demonstrated that prior to TIPS shunting the portal venous contribution to hepatic perfusion was reduced to 29.2%, this reduction being due to portal hypertension. After TIPS placement a significant increase in portal venous perfusion was observed (38.2%; P<0.02). TIPS shunt occlusion was identified in patients by a significant reduction in the scintigraphically measured portal venous contribution to hepatic blood flow. Hepatic perfusion scintigraphy appears to be a valuable method to determine the immediate effect of TIPS on hepatic blood flow. Post-TIPS follow-up studies of hepatic haemodynamics by liver perfusion scintigraphy appear able to contribute to the detection of TIPS shunt occlusion before the clinical consequences of this complication have become apparent. (orig.). With 4 figs., 3 tabs.

  3. Integrated Ocean Management as a Strategy to Meet Rapid Climate Change: The Norwegian Case

    OpenAIRE

    Hoel, Alf Håkon; Olsen, Erik

    2012-01-01

    The prospects of rapid climate change and the potential existence of tipping points in marine ecosystems where nonlinear change may result from them being overstepped, raises the question of strategies for coping with ecosystem change. There is broad agreement that the combined forces of climate change, pollution and increasing economic activities necessitates more comprehensive approaches to oceans management, centering on the concept of ecosystem-based oceans management. This article addres...

  4. Abiotic stress leads to somatic and heritable changes in homologous recombination frequency, point mutation frequency and microsatellite stability in Arabidopsis plants

    International Nuclear Information System (INIS)

    In earlier studies, we showed that abiotic stresses, such as ionizing radiation, heavy metals, temperature and water, trigger an increase in homologous recombination frequency (HRF). We also demonstrated that many of these stresses led to inheritance of high-frequency homologous recombination, HRF. Although an increase in recombination frequency is an important indicator of genome rearrangements, it only represents a minor portion of possible stress-induced mutations. Here, we analyzed the influence of heat, cold, drought, flood and UVC abiotic stresses on two major types of mutations in the genome, point mutations and small deletions/insertions. We used two transgenic lines of Arabidopsis thaliana, one allowing an analysis of reversions in a stop codon-containing inactivated β-glucuronidase transgene and another one allowing an analysis of repeat stability in a microsatellite-interrupted β-glucuronidase transgene. The transgenic Arabidopsis line carrying the β-glucuronidase-based homologous recombination substrate was used as a positive control. We showed that the majority of stresses increased the frequency of point mutations, homologous recombination and microsatellite instability in somatic cells, with the frequency of homologous recombination being affected the most. The analysis of transgenerational changes showed an increase in HRF to be the most prominent effect observed in progeny. Significant changes in recombination frequency were observed upon exposure to all types of stress except drought, whereas changes in microsatellite instability were observed upon exposure to UVC, heat and cold. The frequency of point mutations in the progeny of stress-exposed plants was the least affected; an increase in mutation frequency was observed only in the progeny of plants exposed to UVC. We thus conclude that transgenerational changes in genome stability in response to stress primarily involve an increase in recombination frequency.

  5. Abiotic stress leads to somatic and heritable changes in homologous recombination frequency, point mutation frequency and microsatellite stability in Arabidopsis plants

    Energy Technology Data Exchange (ETDEWEB)

    Yao Youli, E-mail: youli.yao@uleth.ca [Department of Biological Sciences, University of Lethbridge, Lethbridge, T1K 3M4 Alberta (Canada); Kovalchuk, Igor, E-mail: igor.kovalchuk@uleth.ca [Department of Biological Sciences, University of Lethbridge, Lethbridge, T1K 3M4 Alberta (Canada)

    2011-02-10

    In earlier studies, we showed that abiotic stresses, such as ionizing radiation, heavy metals, temperature and water, trigger an increase in homologous recombination frequency (HRF). We also demonstrated that many of these stresses led to inheritance of high-frequency homologous recombination, HRF. Although an increase in recombination frequency is an important indicator of genome rearrangements, it only represents a minor portion of possible stress-induced mutations. Here, we analyzed the influence of heat, cold, drought, flood and UVC abiotic stresses on two major types of mutations in the genome, point mutations and small deletions/insertions. We used two transgenic lines of Arabidopsis thaliana, one allowing an analysis of reversions in a stop codon-containing inactivated {beta}-glucuronidase transgene and another one allowing an analysis of repeat stability in a microsatellite-interrupted {beta}-glucuronidase transgene. The transgenic Arabidopsis line carrying the {beta}-glucuronidase-based homologous recombination substrate was used as a positive control. We showed that the majority of stresses increased the frequency of point mutations, homologous recombination and microsatellite instability in somatic cells, with the frequency of homologous recombination being affected the most. The analysis of transgenerational changes showed an increase in HRF to be the most prominent effect observed in progeny. Significant changes in recombination frequency were observed upon exposure to all types of stress except drought, whereas changes in microsatellite instability were observed upon exposure to UVC, heat and cold. The frequency of point mutations in the progeny of stress-exposed plants was the least affected; an increase in mutation frequency was observed only in the progeny of plants exposed to UVC. We thus conclude that transgenerational changes in genome stability in response to stress primarily involve an increase in recombination frequency.

  6. Continuous Innovation and Business Development in High-tech SME Clusters: A Change Point Analysis and Assessment Approach

    DEFF Research Database (Denmark)

    Müller, Sabine; Neergaard, Helle; Ulhøi, John Parm

    The aim of this paper is to  propose an integrated methodological approach to study  complex  and  longitudinal  processes  such  as  continuous  innovation  and business development in high-tech SME clusters. It draws from four existing and  well-recognised approaches for studying events...... is especially helpful for studies which focus on continuous innovation and  business development in high-tech SME clusters as these  studies  could  benefit  tremendously  from  more qualitative  approaches, which  facilitate  in-depth  understanding  continuous  and  changing  processes. Therefore, major...

  7. GARCH模型变点的Ratio检验%Ratio test to detect change point in GARCH model

    Institute of Scientific and Technical Information of China (English)

    吕会琴; 赵文芝

    2015-01-01

    研究 GARCH 模型参数变点的 Ratio 检验。首先构造了基于残量累积平方和的Ratio统计量,推导了原假设下统计量的极限分布,其次采用Monte Carlo方法检验其有效性,最后以数据为例进一步说明该方法的实用性。%This paper analyzes Ratio tests to detect a change of parameters in GARCH process. The ratio test statistic is based on residual cumulative sum functionals. Under the null hypothesis the asymptotically limiting distribution of the statistic is obtained. Then a Monte Carlo simulation is used for testing the validity. Finally, the real data is used to verify the applicability. The results from both simulation and real data analysis support our argument.

  8. Low Earth orbit journey and ground simulations studies point out metabolic changes in the ESA life support organism Rhodospirillum rubrum

    Science.gov (United States)

    Mastroleo, Felice; Leys, Natalie; Benotmane, Rafi; Vanhavere, Filip; Janssen, Ann; Hendrickx, Larissa; Wattiez, Ruddy; Mergeay, Max

    MELiSSA (Micro-Ecological Life Support System Alternative) is a project of closed regenerative life support system for future space flights developed by the European Space Agency. It consists of interconnected processes (i.e. bioreactors, higher plant compartments, filtration units,..) targeting the total recycling of organic waste into oxygen, water and food. Within the MELiSSA loop, the purple non-sulfur alpha-proteobacterium R. rubrum ATCC25903 is used to convert fatty acids released from the upstream raw waste digesting reactor to CO2 and biomass, and to complete the mineralization of aminoacids into NH4+ that will be forwarded to the nitrifying compartment. Among the numerous challenges of the project, the functional stability of the bioreactors in long term and under space flight conditions is of paramount importance for the efficiency of the life support system and consequently the crew safety. Therefore, the physiological and metabolic changes induced by space flight were investigated for R. rubrum. The bacterium grown on solid medium during 2 different 10-day space flights to the ISS (MES- SAGE2, BASE-A experiments) were compared to cells grown on Earth 1 g gravity or modeled microgravity and normal Earth radiation or simulated space flight radiation conditions in order to relate each single stress to its respective cellular response. For simulating the radiation environment, pure gamma and neutron sources were combined, while simulation of changes in gravity where performed using the Random Positioning Machine technology. Transcriptome analysis using R. rubrum total genome DNA-chip showed up-regulation of genes involved in oxidative stress response after a 10-day mission inside the ISS, without loss of viability. As an example, alkyl hydroperoxide reductase, thioredoxin reductase and bacterioferritin genes are least 2 fold induced although the radiation dose experienced by the bacterium (4 mSv) is very low compared to its radiotolerance (D10 = 100 Sv

  9. Extending the Functionality of Behavioural Change-Point Analysis with k-Means Clustering: A Case Study with the Little Penguin (Eudyptula minor.

    Directory of Open Access Journals (Sweden)

    Jingjing Zhang

    Full Text Available We present a simple framework for classifying mutually exclusive behavioural states within the geospatial lifelines of animals. This method involves use of three sequentially applied statistical procedures: (1 behavioural change point analysis to partition movement trajectories into discrete bouts of same-state behaviours, based on abrupt changes in the spatio-temporal autocorrelation structure of movement parameters; (2 hierarchical multivariate cluster analysis to determine the number of different behavioural states; and (3 k-means clustering to classify inferred bouts of same-state location observations into behavioural modes. We demonstrate application of the method by analysing synthetic trajectories of known 'artificial behaviours' comprised of different correlated random walks, as well as real foraging trajectories of little penguins (Eudyptula minor obtained by global-positioning-system telemetry. Our results show that the modelling procedure correctly classified 92.5% of all individual location observations in the synthetic trajectories, demonstrating reasonable ability to successfully discriminate behavioural modes. Most individual little penguins were found to exhibit three unique behavioural states (resting, commuting/active searching, area-restricted foraging, with variation in the timing and locations of observations apparently related to ambient light, bathymetry, and proximity to coastlines and river mouths. Addition of k-means clustering extends the utility of behavioural change point analysis, by providing a simple means through which the behaviours inferred for the location observations comprising individual movement trajectories can be objectively classified.

  10. Role of attractive forces in tapping tip force microscopy

    DEFF Research Database (Denmark)

    Kyhle, Anders; Sørensen, Alexis Hammer; Bohr, Jakob

    1997-01-01

    We present experimental and numerical results demonstrating the drastic influence of attractive forces on the behaviour of the atomic force microscope when operated in the resonant tapping tip mode in an ambient environment. It is often assumed that tapping is related to repulsive interaction....... In contrast, we find that in general the attractive forces are the most dominant interaction in this mode of operation. We show that attractive forces in combination with the repulsive elastic type of forces cause points of instability in the parameter space constituted by: the cantilever swing amplitude...

  11. From the twig tips to the deeper branches

    DEFF Research Database (Denmark)

    Betson, Martha; Nejsum, Peter; Stothard, J. Russell

    2013-01-01

    Ascaris lumbricoides and Ascaris suum continues. From an applied perspective, however, molecular markers help to "tag" and "track" worms during their transmission cycle(s), providing new insights into host range, as well as methods for assessing parasite population dynamics through time and contingent...... upon disease control. While useful in determining dynamics at the tips of the evolutionary tree, these molecular tools also provide insights into deeper evolutionary branches. Although Ascaris is found throughout the globe, molecular analysis of worms retrieved from sub-Saharan Africa point towards...

  12. Capillary Interactions between a Probe Tip and a Nanoparticle

    Institute of Scientific and Technical Information of China (English)

    SUN Li-Ning; WANG Le-Feng; RONG Wei-Bin

    2008-01-01

    To understand capillary interactions between probe tips and nanoparticles under ambient conditions,a theoretical model of capillary forces between them is developed based on the geometric relations. It is found that the contribution of surface tension force to the total capillary force attains to similar order of magnitude as the capillary pressure force in many cases.It is also shown that the tip shape and the radial distance of the meniscus have great influence on the capillary force.The capillary force decreases with the increasing separation distances,and the variance of the contact angles may change the magnitudes of capillary forces several times at large radial distances.The applicability of the symmetric meniscus approximation is discussed.

  13. TIP-1 Has PDZ Scaffold Antagonist Activity

    Science.gov (United States)

    Alewine, Christine; Olsen, Olav; Wade, James B.

    2006-01-01

    PDZ proteins usually contain multiple protein–protein interaction domains and act as molecular scaffolds that are important for the generation and maintenance of cell polarity and cell signaling. Here, we identify and characterize TIP-1 as an atypical PDZ protein that is composed almost entirely of a single PDZ domain and functions as a negative regulator of PDZ-based scaffolding. We found that TIP-1 competes with the basolateral membrane mLin-7/CASK complex for interaction with the potassium channel Kir 2.3 in model renal epithelia. Consequently, polarized plasma membrane expression of Kir 2.3 is disrupted resulting in pronounced endosomal targeting of the channel, similar to the phenotype observed for mutant Kir 2.3 channels lacking the PDZ-binding motif. TIP-1 is ubiquitously expressed, raising the possibility that TIP-1 may play a similar role in regulating the expression of other membrane proteins containing a type I PDZ ligand. PMID:16855024

  14. Can't sleep? Try these tips

    Science.gov (United States)

    ... medlineplus.gov/ency/patientinstructions/000853.htm Can’t sleep? Try these tips To use the sharing features ... time. But if it happens often, lack of sleep can affect your health and make it hard ...

  15. Brain Injury Safety Tips and Prevention

    Science.gov (United States)

    ... this? Submit Button Brain Injury Safety Tips and Prevention Recommend on Facebook Tweet Share Compartir There are ... More HEADS UP Video: Brain Injury Safety and Prevention frame support disabled and/or not supported in ...

  16. 10 Healthy Breakfast and Lunch Tips

    Science.gov (United States)

    ... Back to School, the Healthy Way 10 Healthy Breakfast and Lunch Tips Past Issues / Fall 2012 Table ... have shown that children who eat healthful, balanced breakfasts and lunches are more alert throughout the school ...

  17. Tips for Teens with Diabetes: About Diabetes

    Science.gov (United States)

    National Diabetes Education Program (NDEP), 2010

    2010-01-01

    Diabetes is a serious disease. It means that one's blood glucose, also called blood sugar, is too high. Having too much glucose in a person's blood is not healthy. This paper offers tips for managing diabetes.

  18. Food Safety Tips for College Students

    Science.gov (United States)

    ... 286) Actions ${title} Loading... Food Safety Tips for College Students When students pack up for college, they take ... food safety considerations when cooking with these appliances. College students are under a lot of pressure and they ...

  19. Tips for Working With External Reviewers.

    Science.gov (United States)

    Bleich, Michael R

    2015-12-01

    Leaders are responsible for creating a culture of quality and safety within a highly regulated industry. Five tips for working with regulators are presented from a leadership coaching framework. PMID:26641150

  20. Ten Tips to Prevent Infections During Pregnancy

    Centers for Disease Control (CDC) Podcasts

    2007-12-14

    This podcast gives 10 tips for preventing infections during pregnancy.  Created: 12/14/2007 by National Center for Birth Defects and Developmental Disabilities (NCBDDD).   Date Released: 1/10/2008.

  1. Tips for Travel and Aircraft Flight

    Science.gov (United States)

    ... Knowledge and support Tips for Travel and Aircraft Flight Category: FAQ's Tags: Risks Archives Breast Cancer Survivors ... limb carefully) and apply pressure as needed. DURING FLIGHT Keep your seat belt loosely fastened so that ...

  2. Beginning SharePoint 2010 Administration Windows SharePoint Foundation 2010 and Microsoft SharePoint Server 2010

    CERN Document Server

    Husman, Göran

    2010-01-01

    Complete coverage on the latest advances in SharePoint 2010 administration. SharePoint 2010 comprises an abundance of new features, and this book shows you how to take advantage of all SharePoint 2010's many improvements. Written by a four-time SharePoint MVP, Beginning SharePoint 2010 Administration begins with a comparison of SharePoint 2010 compared to the previous version and then examines the differences between WSS 4.0 and MSS 2010. Packed with step-by-step instructions, tips and tricks, and real-world examples, this book dives into the basics of how to install, manage, and administrate

  3. Effects of the AFM tip trace on nanobundles formation on the polymer surface

    Energy Technology Data Exchange (ETDEWEB)

    Yan Yongda, E-mail: yanyongda@yahoo.com.cn [Key Laboratory of Micro-systems and Micro-structures Manufacturing of Ministry of Education, Harbin Institute of Technology, Harbin, Heilongjiang 150001 (China); Center for Precision Engineering, Harbin Institute of Technology, Harbin, Heilongjiang 150001 (China); Sun Yang; Yang Yanting; Hu Zhenjiang [Key Laboratory of Micro-systems and Micro-structures Manufacturing of Ministry of Education, Harbin Institute of Technology, Harbin, Heilongjiang 150001 (China); Center for Precision Engineering, Harbin Institute of Technology, Harbin, Heilongjiang 150001 (China); Zhao Xuesen [Center for Precision Engineering, Harbin Institute of Technology, Harbin, Heilongjiang 150001 (China)

    2012-10-01

    Highlights: Black-Right-Pointing-Pointer The AFM tip is used to scratch the PC surface once to form nanobundle structures. Black-Right-Pointing-Pointer Effects of the tip trace on bundles formation are studied based on a modified AFM. Black-Right-Pointing-Pointer The sample scanning mode is feasible for perfect nanobundle structures formation. - Abstract: Atomic Force Microscope (AFM) has become a popular experimental tool for the nanotribological studies. Nanobundles formation perpendicular to the scanning direction has been reported as a typical wear mode for the thermoplastics, and such bundle structures are also considered as sinusoidal wave micro-/nanostructures now. In the present study, the AFM tip based nanomechanical machining method is employed to scratch a polymer Polycarbonate (PC) surface for only once with the normal load of several micro-Newtons in order to achieve the perfect regular nanobundle structures. Based on a modified AFM system, effects of different tip traces in the tip scanning mode and in the sample scanning mode on nanobundles formation on the PC surface are studied. The experimental results show that the controlled reciprocal movement of the stage in the sample scanning mode is feasible for perfect nanobundle structures formation. Moreover, effects of the normal load and the feed on bundles formation in the sample scanning mode are analyzed. Experimental results reveal that the feed value directly affects the formed patterns including the bundles and grooves structures. The reciprocal effect of the tip trace is the decisive factor of forming ideal nanobundles. The repeating times on the same area acted by the tip which are larger than twice are necessary to form a perfect nanobundle structure.

  4. The Social Norm of Tipping: A Review

    OpenAIRE

    Azar, Ofer H.

    2003-01-01

    Tipping is an important phenomenon, both because of its economic magnitude and because of the insights it suggests about economic behavior in general. It is closely related to several areas in economics, including labor economics, industrial organization, social economics, behavioral economics, and public policy. Unfortunately, no published article integrates and synthesizes the research on tipping. This makes it hard for scholars to get an overview of this research area without reading dozen...

  5. Effect of Tip-Speed Constraints on the Optimized Design of a Wind Turbine

    Energy Technology Data Exchange (ETDEWEB)

    Dykes, K.; Resor, B.; Platt, A.; Guo, Y.; Ning, A.; King, R.; Parsons, T.; Petch, D.; Veers, P.

    2014-10-01

    This study investigates the effect of tip-velocity constraints on system levelized cost of energy (LCOE). The results indicate that a change in maximum tip speed from 80 to 100~m/s could produce a 32% decrease in gearbox weight (a 33% reduction in cost) which would result in an overall reduction of 1%-9% in system LCOE depending on the design approach. Three 100~m/s design cases were considered including a low tip-speed ratio/high-solidity rotor design, a high tip-speed ratio/ low-solidity rotor design, and finally a flexible blade design in which a high tip-speed ratio was used along with removing the tip deflection constraint on the rotor design. In all three cases, the significant reduction in gearbox weight caused by the higher tip-speed and lower overall gear ratio was counterbalanced by increased weights for the rotor and/or other drivetrain components and the tower. As a result, the increased costs of either the rotor or drivetrain components offset the overall reduction in turbine costs from down-sizing the gearbox. Other system costs were not significantly affected, whereas energy production was slightly reduced in the 100~m/s case low tip-speed ratio case and increased in the high tip-speed ratio case. This resulted in system cost of energy reductions moving from the 80~m/s design to the 100~m/s designs of 1.2% for the low tip-speed ratio, 4.6% for the high tip-speed ratio, and 9.5% for the final flexible case (the latter result is optimistic because the impact of deflection of the flexible blade on power production was not modeled). Overall, the results demonstrate that there is a trade-off in system design between the maximum tip velocity and the overall wind plant cost of energy, and there are many trade-offs within the overall system in designing a turbine for a high maximum tip velocity.

  6. TOPOLOGY AND VORTEX STRUCTURES OF A CURVING TURBINE CASCADE WITH TIP CLEARANCE ( Ⅰ )- EXPERIMENTAL MODEL AND TOPOLOGICAL FLOW PATTERNS ON BOTH ENDWALLS AND BLADE SURFACES

    Institute of Scientific and Technical Information of China (English)

    杨庆海; 黄洪雁; 韩万今

    2002-01-01

    By means of ink trace visualization of the flows in conventional straight, positively curved and negatively curved cascades with tip clearance, and measurement of the aerodynamic parameters in the transverse section, and by appling topology theory, the structures on both endwalls and blade surfaces were analyzed. Compared with conventional straight cascade, blade positive curving eliminates the separation line of the upper passage vortex and leads the secondary vortex to change from close separation to open separation,while blade negative curving effects merely the positions of singular points and the intensities and scales of vortex.

  7. Association Between Media Dose, Ad Tagging, and Changes in Web Traffic for a National Tobacco Education Campaign: A Market-Level Longitudinal Study

    Science.gov (United States)

    Davis, Kevin C; Patel, Deesha; Rodes, Robert; Beistle, Diane

    2016-01-01

    Background In 2012, the US Centers for Disease Control and Prevention (CDC) launched Tips From Former Smokers (Tips), the first federally funded national tobacco education campaign. In 2013, a follow-up Tips campaign aired on national cable television networks, radio, and other channels, with supporting digital advertising to drive traffic to the Tips campaign website. Objective The objective of this study was to use geographic and temporal variability in 2013 Tips campaign television media doses and ad tagging to evaluate changes in traffic to the campaign website in response to specific doses of campaign media. Methods Linear regression models were used to estimate the dose-response relationship between weekly market-level television gross rating points (GRPs) and weekly Web traffic to the Tips campaign website. This relationship was measured using unique visitors, total visits, and page views as outcomes. Ad GRP effects were estimated separately for ads tagged with the Tips campaign website URL and 1-800-QUIT-NOW. Results In the average media market, an increase of 100 television GRPs per week for ads tagged with the Tips campaign website URL was associated with an increase of 650 unique visitors (Padvertising efforts on consumers’ use of campaign-specific websites. PMID:26887959

  8. Construction of a Dual-Tip Scanning Tunneling Microscope: a Prototype Nanotechnology Workstation.

    Science.gov (United States)

    Voelker, Mark Alan

    1993-01-01

    This dissertation describes the construction and performance of a dual-tip scanning tunneling microscope (STM). The microscope was built as a prototype nanotechnology workstation, a general purpose instrument designed to give a researcher the ability to investigate and manipulate nanometer scale structures. Chapter One describes the genesis and development of the concept of nanotechnology, from the atomic hypothesis of Democritus to modern developments in synthetic chemistry. Nanometer scale electronics (molecular electronics) is introduced and the state of the art in this field is described. The dual-tip scanning probe microscope is proposed as a way to address individual molecular electronic devices, a key goal in realizing nanometer scale electronic technology. Investigation of microtubules, a proposed nanometer scale intracellular biological information processing system, is also discussed. Chapter Two reviews the history and fundamental physics of STM, along with the related techniques of Field Ion Microscopy (FIM) and Ballistic Electon Emission Microscopy (BEEM). BEEM is used to introduce the physics of the dual -tip STM. Other dual-probe systems are also described. Chapter Three covers the design and construction of the dual-tip STM. Both hardware and software are described in detail. Chapter Four presents the results obtained with the dual-tip STM, including dual-tip images and noise measurements for the electronic circuitry. The last chapter, Chapter Five, contains suggested design changes for improving the performance of the dual -tip microscope and descriptions of experiments that can be performed with an improved instrument. Design and use of a nanotechnology workstation in the fields of semiconductor electronics, molecular electronics and cellular biology is discussed. Investigation of neurons grown on a silicon chip with a dual-tip STM system is proposed. Four Appendices present a noise model of the STM tunneling gap and preamplifier, describe

  9. Point correlation dimension can reveal functional changes caused by gap junction blockers in the 4-aminopyridine in vivo rat epilepsy model

    Energy Technology Data Exchange (ETDEWEB)

    Jardanhazy, Anett [Department of Neurology, University of Szeged, Semmelweis u. 6, Szeged H-6725 (Hungary); Molnar, Mark [Department of Psychophysiology, Institute for Psychology of the Hungarian Academy of Sciences, P.O. Box 398, Budapest H-1394 (Hungary)], E-mail: molnar@cogpsyphy.hu; Jardanhazy, Tamas [Department of Neurology, University of Szeged, Semmelweis u. 6, Szeged H-6725 (Hungary)], E-mail: jt@nepsy.szote.u-szeged.hu

    2009-04-15

    The contribution of gap junction (GJ) blockers to seizure initiation was reexamined by means of an analysis on nonlinear dynamics with point correlation dimension (PD2i) at as well as around the primary focus, and mirror focus in an already active 4-aminopyridine-induced in vivo epilepsy model. From the data base of the ECoGs of anesthetized adult rats treated with quinine, a selective blocker of Cx36, and in combination with an additional broad-spectrum GJ blocker, carbenoxolone, 14 cases of each condition were reexamined with a stationarity insensitive nonlinear PD2i method. The blockade of the Cx36 channels decreased the usual drop of the point correlation dimension at the beginning of the seizures, and this was enhanced by the additional use of the global blocker carbenoxolone. The so-called characteristic DC shift just prior to seizure onset denotes a low dimensional seizure event and the recognizable seizures display very variable, rapidly changing dynamics, as revealed by the PD2i analysis. This nonlinear PD2i analysis demonstrated that the different GJ blockers in the already active epileptic model helped seizure initiation, but exerted inhibitory effects on the seizure onset itself, acting differently on the local components of the network organization generating seizure discharges, possibly changing the coupling strengths and time delays in the GJ-s.

  10. Zero-point corrections for isotropic coupling constants for cyclohexadienyl radical, C₆H₇ and C₆H₆Mu: beyond the bond length change approximation.

    Science.gov (United States)

    Hudson, Bruce S; Chafetz, Suzanne K

    2013-04-25

    Zero-point vibrational level averaging for electron spin resonance (ESR) and muon spin resonance (µSR) hyperfine coupling constants (HFCCs) are computed for H and Mu isotopomers of the cyclohexadienyl radical. A local mode approximation previously developed for computation of the effect of replacement of H by D on ¹³C-NMR chemical shifts is used. DFT methods are used to compute the change in energy and HFCCs when the geometry is changed from the equilibrium values for the stretch and both bend degrees of freedom. This variation is then averaged over the probability distribution for each degree of freedom. The method is tested using data for the methylene group of C₆H₇, cyclohexadienyl radical and its Mu analog. Good agreement is found for the difference between the HFCCs for Mu and H of CHMu and that for H of CHMu and CH₂ of the parent radical methylene group. All three of these HFCCs are the same in the absence of the zero point average, a one-parameter fit of the static HFCC, a(0), can be computed. That value, 45.2 Gauss, is compared to the results of several fixed geometry electronic structure computations. The HFCC values for the ortho, meta and para H atoms are then discussed.

  11. Zero-Point Corrections for Isotropic Coupling Constants for Cyclohexadienyl Radical, C6H7 and C6H6Mu: Beyond the Bond Length Change Approximation

    Directory of Open Access Journals (Sweden)

    Bruce S. Hudson

    2013-04-01

    Full Text Available Zero-point vibrational level averaging for electron spin resonance (ESR and muon spin resonance (µSR hyperfine coupling constants (HFCCs are computed for H and Mu isotopomers of the cyclohexadienyl radical. A local mode approximation previously developed for computation of the effect of replacement of H by D on 13C-NMR chemical shifts is used. DFT methods are used to compute the change in energy and HFCCs when the geometry is changed from the equilibrium values for the stretch and both bend degrees of freedom. This variation is then averaged over the probability distribution for each degree of freedom. The method is tested using data for the methylene group of C6H7, cyclohexadienyl radical and its Mu analog. Good agreement is found for the difference between the HFCCs for Mu and H of CHMu and that for H of CHMu and CH2 of the parent radical methylene group. All three of these HFCCs are the same in the absence of the zero point average, a one-parameter fit of the static HFCC, a(0, can be computed. That value, 45.2 Gauss, is compared to the results of several fixed geometry electronic structure computations. The HFCC values for the ortho, meta and para H atoms are then discussed.

  12. Unsteady turbulence interaction in a tip leakage flow downstream of a simulated axial compressor rotor

    Science.gov (United States)

    Ma, Ruolong

    The unsteady behavior of a tip leakage flow downstream of a simulated axial compressor rotor has been studied. The Virginia Tech low speed linear cascade wind tunnel was adapted to model the unsteady tip leakage flow produced by a rotor operating in the vortical wakes of a set of stator vanes. The cascade, consisting of 8 GE rotor B blades, has adjustable tip gap, inlet angle of 65.1°, turning angle of 11.8° and solidity of 1.076. The cascade Reynolds number, based on blade chord, was 393,000. A moving end wall was used to simulate the relative motion between rotor and casing, and vortex generators attached to the moving end wall were used to produce an idealized periodic unsteady vortical inflow similar to that shed by the junction of a row of inlet guide vanes. Measurements of the vortical inflow to the cascade produced by the generators and of the mean blade loading at the mid span are presented. The periodic and aperiodic behavior of the tip leakage flow downstream of the cascade, produced by this vortical disturbance, is also presented using phase and time averaged 3-component turbulence and pressure fluctuation measurements. These measurements are made for tip gap from 0.83% to 3.3% chord and streamwise locations from 0.772% to 1.117% blade spacing axially downstream of the cascade. The phase averaged inflow measurements reveal that the inflow produced by the vortex generators consists of a pair asymmetric counter-rotating vortices embedded in a thin (4.6% chord) endwall boundary layer. The vortices extend some 7.4% chord from the end wall. Their strength is about two orders smaller than the typical circulation of the tip leakage vortices produced by the cascade. Phase averaged single point three component hot-wire measurements downstream of the cascade reveal that the vortical inflow is, however, capable of producing significant large scale fluctuations in the size, strength, structure and position of the tip leakage vortex. These effects increase in

  13. Numerical Simulation on Effects of Pressure Distribution of Wind Turbine Blade with a Tip Vane

    Institute of Scientific and Technical Information of China (English)

    WANG Jian-Wen; JIA Rui-Bo; WU Ke-Qi

    2007-01-01

    It is important to study the pressure distribution on the blade and in the adjacent area while searching the power augmentation theory with adding a tip vane to the wind turbine. This paper shows the CFD simulation relationship of the pressure distribution on the rotor blade and in the adjacent area, after calculating the pressure of the different chordwise and spanwise point on the blade with the tip vane-V(8.8×8) and without the tip vane under tip speed ratio λ 4.5. Combining the isobaric section figure in certain location, it can be seen that the tip vane improve the pressure difference between pressure and suction surface. The most influenced zone is found and these can further display the power augmentation theory of the wind turbine using the tip vane. The simulation calculation was based on N-S equations. 3-D, steady, implicit solver was chosen. Turbulence model was k- ω SST. Discretization cheme is SECOND ORDER UPWIND. Pressure-velocity coupling was a typical SIMPLE scheme. In the whole grid system, two-divided grid formation was adopted, that is, inner region and outer region. Inner region including rectangular solid blade and neighboring, outer region is semi-cylinder. There were together 720,000 nodes with tetra-prism unstructured mesh.

  14. Computational local stiffness analysis of biological cell: High aspect ratio single wall carbon nanotube tip.

    Science.gov (United States)

    TermehYousefi, Amin; Bagheri, Samira; Shahnazar, Sheida; Rahman, Md Habibur; Kadri, Nahrizul Adib

    2016-02-01

    Carbon nanotubes (CNTs) are potentially ideal tips for atomic force microscopy (AFM) due to the robust mechanical properties, nanoscale diameter and also their ability to be functionalized by chemical and biological components at the tip ends. This contribution develops the idea of using CNTs as an AFM tip in computational analysis of the biological cells. The proposed software was ABAQUS 6.13 CAE/CEL provided by Dassault Systems, which is a powerful finite element (FE) tool to perform the numerical analysis and visualize the interactions between proposed tip and membrane of the cell. Finite element analysis employed for each section and displacement of the nodes located in the contact area was monitored by using an output database (ODB). Mooney-Rivlin hyperelastic model of the cell allows the simulation to obtain a new method for estimating the stiffness and spring constant of the cell. Stress and strain curve indicates the yield stress point which defines as a vertical stress and plan stress. Spring constant of the cell and the local stiffness was measured as well as the applied force of CNT-AFM tip on the contact area of the cell. This reliable integration of CNT-AFM tip process provides a new class of high performance nanoprobes for single biological cell analysis. PMID:26652417

  15. Referral of tactile stimuli to action points in virtual reality with reaction force.

    Science.gov (United States)

    Moizumi, Shunjiro; Yamamoto, Shinya; Kitazawa, Shigeru

    2007-09-01

    When we touch something with a tool, we feel the touch at the tip of the tool rather than at the hand. Yamamoto and Kitazawa [Yamamoto, S., Kitazawa, S., 2001b. Sensation at the tips of invisible tools. Nat. Neurosci. 4, 979-980] previously showed that the judgment of the temporal order of two successive stimuli, delivered to the tips of sticks held in each hand, was dramatically altered by crossing the sticks without changing the positions of the hands. This provided evidence for the referral of tactile signals to the tip of a tool in hand. In this study, we examined importance of force feedback from the tool in the referral by manipulating the direction of force feedback in a virtual reality. The virtual tool consisted of a spherical action point that was moved with a stylus in hand. Subjects held two styli, one in each hand, put each action point on each of two buttons in the virtual reality, and were required to judge the order of successive taps, delivered to the two styli. We manipulated the direction of reaction force from each button so that it was congruent or incongruent to the visual configuration of the button. When the arms were uncrossed, judgment primarily depended on whether the action points were crossed or not in the visual space. But when the arms were crossed, judgment critically depended on the direction of force feedback. The results show that tactile signals can be referred to the action point in the virtual reality and that the force feedback becomes a critical factor when the arms are crossed.

  16. The origins of a wind turbine tip vortex

    NARCIS (Netherlands)

    Micallef, D.; Akay, B.; Simao Ferreira, C.J.; Sant, T.; Van Bussel, G.J.W.

    2014-01-01

    The tip vortex of a wind turbine rotor blade originates as a result of a complex distribution of vorticity along the blade tip thickness. While the tip vortex evolution was extensively studied previously in other work, the mechanism of the initiation of the tip vorticity in a 3D rotating environment

  17. Churg-Strauss Syndrome with Necrosis of Toe Tips

    Directory of Open Access Journals (Sweden)

    Waseda,Koichi

    2011-06-01

    Full Text Available Churg-Strauss syndrome (CSS is a granulomatous necrotizing vasculitis of unknown etiology associated with bronchial asthma. Despite affecting small to medium-sized vessels, necrosis of the digits due to vasculitis is extremely rare. We report a case of CSS with necrosis of the toe tips. A 37-year-old woman with asthma, who had been diagnosed with CSS 2 years ago, was admitted to our hospital with an exacerbation of CSS. The patient had a high grade fever and complained of abdominal pain and numbness of the lower extremities. Blood examination revealed marked eosinophilia. The fever pattern, abdominal pain and blood eosinophilia showed improvement by combination treatment with prednisolone and cyclophosphamide. However, the color of her right toe tips changed, and necrosis finally resulted despite antithrombotic therapy. Arteriography showed narrowing of the dorsalis pedis artery and of the more peripheral arteries of her right leg. Stump plasty with negative pressure dressing therapy for the toe tips, but not amputation, was done to preserve the leg function. While numbness of the extremities remained, no recurrence of necrosis was seen. Clinicians need to be aware that rare complications of CSS, including necrosis of the digits, can occur.

  18. Improvement of Scanning Tunneling Microscopy Resolution with H-Sensitized Tips

    Science.gov (United States)

    Martínez, J. I.; Abad, E.; González, C.; Flores, F.; Ortega, J.

    2012-06-01

    Recent scanning tunneling hydrogen microscopy (STHM) experiments on PTCDA (perylene-3,4,9,10-tetracarboxylic-3,4,9,10-dianhydride)/Au(111) have shown unprecedented intramolecular and intermolecular spatial resolution. The origin of this resolution is studied using an accurate STHM theoretical simulation technique that includes a detailed description of the electronic structure of both the tip and sample. Our results show that H2 molecules are dissociated on the Au tip; the adsorbed H atoms change the density of states at the Fermi level (EF) of the tip, increasing its p-orbital character and reducing the s-orbital contribution. Also, due to the interaction with the H-decorated tip, EF is shifted to the middle of the PTCDA lowest unoccupied molecular orbital peak, increasing dramatically the density of states of the sample at EF. These effects give rise to the enhanced STHM resolution.

  19. Understanding the Plasmonics of Nanostructured Atomic Force Microscopy Tips

    CERN Document Server

    Sanders, Alan; Zhang, Liwu; Turek, Vladimir; Sigle, Daniel O; Lombardi, Anna; Weller, Lee; Baumberg, Jeremy J

    2016-01-01

    Structured metallic tips are increasingly important for optical spectroscopies such as tip-enhanced Raman spectroscopy (TERS), with plasmonic resonances frequently cited as a mechanism for electric field enhancement. We probe the local optical response of sharp and spherical-tipped atomic force microscopy (AFM) tips using a scanning hyperspectral imaging technique to identify plasmonic behaviour. Localised surface plasmon resonances which radiatively couple with far-field light are found only for spherical AFM tips, with little response for sharp AFM tips, in agreement with numerical simulations of the near-field response. The precise tip geometry is thus crucial for plasmon-enhanced spectroscopies, and the typical sharp cones are not preferred.

  20. Change point analysis and assessment

    DEFF Research Database (Denmark)

    Müller, Sabine; Neergaard, Helle; Ulhøi, John Parm

    2011-01-01

    The aim of this article is to develop an analytical framework for studying processes such as continuous innovation and business development in high-tech SME clusters that transcends the traditional qualitative-quantitative divide. It integrates four existing and well-recognized approaches...

  1. 75 FR 11226 - Proposed Collection; Comment Request for Tip Reporting Alternative Tip Agreement Used in the...

    Science.gov (United States)

    2010-03-10

    ... Used in the Cosmetology and Barber Industry AGENCY: Internal Revenue Service (IRS), Treasury. ACTION..., the IRS is soliciting comments concerning Tip Reporting Alternative Commitment used in the Cosmetology...: Tip Reporting Alternative Commitment Agreement used in the Cosmetology and Barber Industry. OMB...

  2. 78 FR 13402 - Proposed Collection; Comment Request for Tip Reporting Alternative Tip Agreement Used in the...

    Science.gov (United States)

    2013-02-27

    ... Used in the Cosmetology and Barber Industry AGENCY: Internal Revenue Service (IRS), Treasury. ACTION..., the IRS is soliciting comments concerning tip reporting alternative commitment used in the cosmetology...: Tip Reporting Alternative Commitment Agreement used in the Cosmetology and Barber Industry. OMB...

  3. Nano-Wilhelmy investigation of dynamic wetting properties of AFM tips through tip-nanobubble interaction

    Science.gov (United States)

    Wang, Yuliang; Wang, Huimin; Bi, Shusheng; Guo, Bin

    2016-01-01

    The dynamic wetting properties of atomic force microscopy (AFM) tips are of much concern in many AFM-related measurement, fabrication, and manipulation applications. In this study, the wetting properties of silicon and silicon nitride AFM tips are investigated through dynamic contact angle measurement using a nano-Wilhelmy balance based method. This is done by capillary force measurement during extension and retraction motion of AFM tips relative to interfacial nanobubbles. The working principle of the proposed method and mathematic models for dynamic contact angle measurement are presented. Geometric models of AFM tips were constructed using scanning electronic microscopy (SEM) images taken from different view directions. The detailed process of tip-nanobubble interaction was investigated using force-distance curves of AFM on nanobubbles. Several parameters including nanobubble height, adhesion and capillary force between tip and nanobubbles are extracted. The variation of these parameters was studied over nanobubble surfaces. The dynamic contact angles of the AFM tips were calculated from the capillary force measurements. The proposed method provides direct measurement of dynamic contact angles for AFM tips and can also be taken as a general approach for nanoscale dynamic wetting property investigation. PMID:27452115

  4. Encoding Active Device Elements at Nanowire Tips.

    Science.gov (United States)

    No, You-Shin; Gao, Ruixuan; Mankin, Max N; Day, Robert W; Park, Hong-Gyu; Lieber, Charles M

    2016-07-13

    Semiconductor nanowires and other one-dimensional materials are attractive for highly sensitive and spatially confined electrical and optical signal detection in biological and physical systems, although it has been difficult to localize active electronic or optoelectronic device function at one end of such one-dimensional structures. Here we report a new nanowire structure in which the material and dopant are modulated specifically at only one end of nanowires to encode an active two-terminal device element. We present a general bottom-up synthetic scheme for these tip-modulated nanowires and illustrate this with the synthesis of nanoscale p-n junctions. Electron microscopy imaging verifies the designed p-Si nanowire core with SiO2 insulating inner shell and n-Si outer shell with clean p-Si/n-Si tip junction. Electrical transport measurements with independent contacts to the p-Si core and n-Si shell exhibited a current rectification behavior through the tip and no detectable current through the SiO2 shell. Electrical measurements also exhibited an n-type response in conductance versus water-gate voltage with pulsed gate experiments yielding a temporal resolution of at least 0.1 ms and ∼90% device sensitivity localized to within 0.5 μm from the nanowire p-n tip. In addition, photocurrent experiments showed an open-circuit voltage of 0.75 V at illumination power of ∼28.1 μW, exhibited linear dependence of photocurrent with respect to incident illumination power with an estimated responsivity up to ∼0.22 A/W, and revealed localized photocurrent generation at the nanowire tip. The tip-modulated concept was further extended to a top-down/bottom-up hybrid approach that enabled large-scale production of vertical tip-modulated nanowires with a final synthetic yield of >75% with >4300 nanowires. Vertical tip-modulated nanowires were fabricated into >50 individually addressable nanowire device arrays showing diode-like current-voltage characteristics. These tip

  5. Reconstruction of the Tip-Surface Interaction Potential by Analysis of the Brownian Motion of an Atomic Force Microscope Tip

    NARCIS (Netherlands)

    Willemsen, Oscar H.; Kuipers, Laurens; Werf, van der Kees O.; Grooth, de Bart G.; Greve, Jan

    2000-01-01

    The thermal movement of an atomic force microscope (AFM) tip is used to reconstruct the tip-surface interaction potential. If a tip is brought into the vicinity of a surface, its movement is governed by the sum of the harmonic cantilever potential and the tip-surface interaction potential. By simula

  6. Investigation of Unsteady Tip Clearance Flow in a Low-Speed One and Half Stage Axial Compressor with LES And PIV

    Science.gov (United States)

    Hah, Chunill; Hathaway, Michael; Katz, Joseph; Tan, David

    2015-01-01

    The primary focus of this paper is to investigate how a rotor's unsteady tip clearance flow structure changes in a low speed one and half stage axial compressor when the rotor tip gap size is increased from 0.5 mm (0.49% of rotor tip blade chord, 2% of blade span) to 2.4 mm (2.34% chord, 4% span) at the design condition are investigated. The changes in unsteady tip clearance flow with the 0.62 % tip gap as the flow rate is reduced to near stall condition are also investigated. A Large Eddy Simulation (LES) is applied to calculate the unsteady flow field at these three flow conditions. Detailed Stereoscopic PIV (SPIV) measurements of the current flow fields were also performed at the Johns Hopkins University in a refractive index-matched test facility which renders the compressor blades and casing optically transparent. With this setup, the unsteady velocity field in the entire flow domain, including the flow inside the tip gap, can be measured. Unsteady tip clearance flow fields from LES are compared with the PIV measurements and both LES and PIV results are used to study changes in tip clearance flow structures. The current study shows that the tip clearance vortex is not a single structure as traditionally perceived. The tip clearance vortex is formed by multiple interlaced vorticities. Therefore, the tip clearance vortex is inherently unsteady. The multiple interlaced vortices never roll up to form a single structure. When phased-averaged, the tip clearance vortex appears as a single structure. When flow rate is reduced with the same tip gap, the tip clearance vortex rolls further upstream and the tip clearance vortex moves further radially inward and away from the suction side of the blade. When the tip gap size is increased at the design flow condition, the overall tip clearance vortex becomes stronger and it stays closer to the blade suction side and the vortex core extends all the way to the exit of the blade passage. Measured and calculated unsteady flow

  7. An experimental investigation on the tip leakage noise in axial-flow fans with rotating shroud

    Science.gov (United States)

    Canepa, Edward; Cattanei, Andrea; Mazzocut Zecchin, Fabio; Milanese, Gabriele; Parodi, Davide

    2016-08-01

    The tip leakage noise generated by a shrouded rotor of an axial-flow fan has been experimentally studied. The measurements have been taken at high flow rate and at the design point in a hemi-anechoic chamber, at constant rotational speed and during speed ramps. A test plenum designed according to ISO 10302 has been employed to modify the operating conditions and different inlet configurations, ducted and unducted with standard and reduced tip gap, have been considered. The basic features of the inflow have been studied by means of aerodynamic measurements taken upstream of the rotor. To separate the noise generating mechanisms from the acoustic propagation effects, the acoustic response function of the test configuration has been computed employing the spectral decomposition method, and then it has been compared with the velocity-scaled, constant-Strouhal number SPL. In this way, the noise components related to the tip leakage flow have been identified and their connection with geometry have been highlighted. The broadband part of the spectra and the peaks related to the tip leakage flow are affected by the same propagation effects, but show a different dependence on the rotational speed and on the operating point. The upstream geometry affects the radiated noise much more than the performance and even a strong reduction in the tip-gap cannot completely eliminate the related noise.

  8. Training Student and Adult Assistants, Interns, and Volunteers: Tips for New Librarians Servicing Small Libraries.

    Science.gov (United States)

    Smallwood, Carol

    1999-01-01

    Provides tips for designing effective training programs for library assistants. Discusses general points to consider; acquainting new assistants with the library; and assigning jobs that reflect assistants' interests. Suggests special projects for assistants including: arranging displays; cataloging; covering paperback and hardback books;…

  9. The regularized blind tip reconstruction algorithm as a scanning probe microscopy tip metrology method

    CERN Document Server

    Jozwiak, G; Masalska, A; Gotszalk, T; Ritz, I; Steigmann, H

    2011-01-01

    The problem of an accurate tip radius and shape characterization is very important for determination of surface mechanical and chemical properties on the basis of the scanning probe microscopy measurements. We think that the most favorable methods for this purpose are blind tip reconstruction methods, since they do not need any calibrated characterizers and might be performed on an ordinary SPM setup. As in many other inverse problems also in case of these methods the stability of the solution in presence of vibrational and electronic noise needs application of so called regularization techniques. In this paper the novel regularization technique (Regularized Blind Tip Reconstruction - RBTR) for blind tip reconstruction algorithm is presented. It improves the quality of the solution in presence of isotropic and anisotropic noise. The superiority of our approach is proved on the basis of computer simulations and analysis of images of the Budget Sensors TipCheck calibration standard. In case of characterization ...

  10. Gravity sensing in tip-growing cells.

    Science.gov (United States)

    Sievers, A; Buchen, B; Hodick, D

    1996-08-01

    In addition to the statocytes of roots and shoots, a number of tip-growing cells also sense gravity, which influences the cells' growth and development. Since these tip-growing cells are highly suitable for observations in vivo, the movement and sedimentation of their statoliths can be studied in detail. Experimental manipulation by centrifugation, drug application, optical tweezers or microgravity can be monitored by light microscopy. The statoliths are localized in distinct cytoplasmic areas by interactions with actin filaments or microtubules, and their sedimentation seems to be narrowly confined. Since gravisensing and the graviresponse take place within the same cell, the gravitropic signal transduction chain is not complicated by signal transmission between sensing and responding cells. Studies on tip-growing cells have now enabled the formulation of models explaining positive and negative gravitropism.

  11. Tomography of Majorana fermions with STM tips

    Science.gov (United States)

    Chevallier, Denis; Klinovaja, Jelena

    2016-07-01

    We investigate numerically the possibility to detect the spatial profile of Majorana fermions (MFs) by using STM tips that are made of either normal or superconducting material. In both cases, we are able to resolve the localization length and the oscillation period of the MF wave function. We show that the tunneling between the substrate and the tip, necessary to get the information on the wave-function oscillations, has to be weaker in the case of a superconducting probe. In the strong tunneling regime, the differential conductance saturates making it more difficult to observe the exponential decay of MFs. The temperature broadening of the profile is strongly suppressed in the case of the superconducting tip resulting, generally, in better resolution.

  12. Three Points Approach (3PA) for urban flood risk management: A tool to support climate change adaptation through transdisciplinarity and multifunctionality

    DEFF Research Database (Denmark)

    Fratini, Chiara; Geldof, Govert Daan; Kluck, J.;

    2012-01-01

    Urban flood risk is increasing as a consequence of climate change and growing impervious surfaces. Increasing complexity of the urban context, gradual loss of tacit knowledge and decreasing social awareness are at the same time leading to inadequate choices with respect to urban flood risk...... management (UFRM). The European Flood Risk Directive emphasises the need for non-structural measures aimed at urban resilience and social preparedness. The Three Points Approach (3PA) provides a structure facilitating the decision making processes dealing with UFRM. It helps to accept the complexity...... of the urban context and promotes transdisciplinarity and multifunctionality. The 3PA introduces three domains wherein water professionals may act and where aspects valued by different stakeholders come into play: (1) technical optimisation, dealing with standards and guidelines for urban drainage systems; (2...

  13. La red sobre trabajo infantil peligroso (Red Tip The hazardous child labor network (Red Tip

    Directory of Open Access Journals (Sweden)

    Walter Varillas

    2003-01-01

    Full Text Available En el mundo, aproximadamente 351.7 millones de niños entre 5 y 17 años realizaban algún tipo de actividad económica, de ellos 170.5 millones (48.5% realizaban algún tipo de trabajo considerado peligroso. Un alto porcentaje se encuentra en la agricultura, otros en minas, manufacturas, ladrilleras, predominantemente en la economía informal. El Convenio 138 (cobre la edad mínima de admisión en el empleo de la OIT y el Convenio 182 (sobre las peores formas de trabajo infantil, definen como trabajo infantil peligroso el que puede afectar la salud, seguridad y moralidad de los menores. Estudios específicos sobre los menores muestran su susceptibilidad particular frente a los riesgos laborales, aumentando la peligrosidad para su normal desarrollo y crecimiento: "los niños no son adultos pequeños". Los profesionales de la seguridad y salud en el trabajo pueden colaborar con los profesionales y las organizaciones especializadas en el trabajo infantil, en la definición y caracterización de lo que significa el trabajo infantil peligroso. Para ello se ha conformado la Red sobre Trabajo Infantil Peligroso (Red TIP, con la finalidad de articular estos dos espacios, orientados a eliminar el trabajo infantil peligroso y rescatar al menor y devolverle la oportunidad de sonreír ahora y en el futuro.In the world, approximately 351.7 millions children between 5 and 17 years old work. Of them, 170,5 millions (48.5% work at the hazardous child labor forms. A high percentage is in agriculture, others in mines, manufactures, brick makers, predominantly in informal economy. The 138 Convention of ILO and the 182 Convention, define as hazardous child labor activities that can affect the health, safety and morality of the children. Studies on the children at work point out their particular susceptibility to some occupational risks, increasing the danger for their normal development and growth. "They are not little adults". The occupational health

  14. Twelve tips for "flipping" the classroom.

    Science.gov (United States)

    Moffett, Jennifer

    2015-04-01

    The flipped classroom is a pedagogical model in which the typical lecture and homework elements of a course are reversed. The following tips outline the steps involved in making a successful transition to a flipped classroom approach. The tips are based on the available literature alongside the author's experience of using the approach in a medical education setting. Flipping a classroom has a number of potential benefits, for example increased educator-student interaction, but must be planned and implemented carefully to support effective learning. PMID:25154646

  15. Windows 7 Annoyances Tips, Secrets, and Solutions

    CERN Document Server

    Karp, David

    2010-01-01

    Windows 7 may be faster and more stable than Vista, but it's a far cry from problem-free. David A. Karp comes to the rescue with the latest in his popular Windows Annoyances series. This thorough guide gives you the tools you need to fix the troublesome parts of this operating system, plus the solutions, hacks, and timesaving tips to make the most of your PC. Streamline Windows Explorer, improve the Search tool, eliminate the Green Ribbon of Death, and tame User Account Control promptsExplore powerful Registry tips and tools, and use them to customize every aspect of Windows and solve its sho

  16. Twelve tips for "flipping" the classroom.

    Science.gov (United States)

    Moffett, Jennifer

    2015-04-01

    The flipped classroom is a pedagogical model in which the typical lecture and homework elements of a course are reversed. The following tips outline the steps involved in making a successful transition to a flipped classroom approach. The tips are based on the available literature alongside the author's experience of using the approach in a medical education setting. Flipping a classroom has a number of potential benefits, for example increased educator-student interaction, but must be planned and implemented carefully to support effective learning.

  17. Relative importance of modularity and other morphological attributes on different types of lithic point weapons: assessing functional variations.

    Directory of Open Access Journals (Sweden)

    Rolando González-José

    Full Text Available The specific using of different prehistoric weapons is mainly determined by its physical properties, which provide a relative advantage or disadvantage to perform a given, particular function. Since these physical properties are integrated to accomplish that function, examining design variables and their pattern of integration or modularity is of interest to estimate the past function of a point. Here we analyze a composite sample of lithic points from southern Patagonia likely formed by arrows, thrown spears and hand-held points to test if they can be viewed as a two-module system formed by the blade and the stem, and to evaluate the degree in which shape, size, asymmetry, blade: stem length ratio, and tip angle explain the observed variance and differentiation among points supposedly aimed to accomplish different functions. To do so we performed a geometric morphometric analysis on 118 lithic points, departing from 24 two-dimensional landmark and semi landmarks placed on the point's contour. Klingenberg's covariational modularity tests were used to evaluate different modularity hypotheses, and a composite PCA including shape, size, asymmetry, blade: stem length ratio, and tip angle was used to estimate the importance of each attribute to explaining variation patterns. Results show that the blade and the stem can be seen as "near decomposable units" in the points integrating the studied sample. However, this modular pattern changes after removing the effects of reduction. Indeed, a resharpened point tends to show a tip/rest of the point modular pattern. The composite PCA analyses evidenced three different patterns of morphometric attributes compatible with arrows, thrown spears, and hand-held tools. Interestingly, when analyzed independently, these groups show differences in their modular organization. Our results indicate that stone tools can be approached as flexible designs, characterized by a composite set of interacting morphometric

  18. A Rotor Tip Vortex Tracing Algorithm for Image Post-Processing

    Science.gov (United States)

    Overmeyer, Austin D.

    2015-01-01

    A neurite tracing algorithm, originally developed for medical image processing, was used to trace the location of the rotor tip vortex in density gradient flow visualization images. The tracing algorithm was applied to several representative test images to form case studies. The accuracy of the tracing algorithm was compared to two current methods including a manual point and click method and a cross-correlation template method. It is shown that the neurite tracing algorithm can reduce the post-processing time to trace the vortex by a factor of 10 to 15 without compromising the accuracy of the tip vortex location compared to other methods presented in literature.

  19. The role of tip-localized mitochondria in hyphal growth.

    Science.gov (United States)

    Levina, Natalia N; Lew, Roger R

    2006-02-01

    Hyphal tip-growing organisms have a high density of tip-localized mitochondria which maintain a membrane potential based on Rhodamine 123 fluorescence, but do not produce ATP based on the absence of significant oxygen consumption. Two possible roles of these mitochondria in tip growth were examined: Calcium sequestration and biogenesis, because tip-high cytoplasmic calcium gradients are a common feature of tip-growing organisms, and the volume expansion as the tip extends would require a continuous supply of additional mitochondria. Co-localization of calcium-sensitive fluorescent dye and mitochondria-specific fluorescent dyes showed that the tip-localized mitochondria do contain calcium, and therefore, may function in calcium clearance from the cytoplasm. Short-term inhibition of DNA synthesis or mitochondrial protein synthesis did not affect either tip growth, or mitochondrial shape or distribution. Therefore, mitochondrial biogenesis may not occur from the tip-localized mitochondria in hyphal organisms. PMID:16455272

  20. Numerical investigation of three wind turbine blade tips

    DEFF Research Database (Denmark)

    Johansen, J.; Sørensen, Niels N.

    2002-01-01

    The complex three-dimensional flow around three different tip shapes on a rotating wind turbine blade is investigated and analyzed using Computational Fluid Dynamics. Differences in production, flapwise bending moments and forces are discussed. A methodfor determining the local inflow angle....... The Taper tip keeps the higher loading causing the flapwise bending moment to be higher as seen inmeasurements. To determine the radial variation of lift and drag coefficients the local inflow angle of attack is determined. It is shown that the Standard tip experiences a slightly larger angle of attack...... at the tip compared to the two tapered tips. Thelift coefficients are kept at a more constant level for the two tapered tips due to the decrease in chord, while the drag coefficients actually decrease for the two tapered tips, especially for the Swept tip. For the Swept tip at 12 m/s both lift...

  1. Study of tip loss corrections using CFD rotor computations

    Science.gov (United States)

    Shen, W. Z.; Zhu, W. J.; Sørensen, J. N.

    2014-12-01

    Tip loss correction is known to play an important role for engineering prediction of wind turbine performance. There are two different types of tip loss corrections: tip corrections on momentum theory and tip corrections on airfoil data. In this paper, we study the latter using detailed CFD computations for wind turbines with sharp tip. Using the technique of determination of angle of attack and the CFD results for a NordTank 500 kW rotor, airfoil data are extracted and a new tip loss function on airfoil data is derived. To validate, BEM computations with the new tip loss function are carried out and compared with CFD results for the NordTank 500 kW turbine and the NREL 5 MW turbine. Comparisons show that BEM with the new tip loss function can predict correctly the loading near the blade tip.

  2. Study of tip loss corrections using CFD rotor computations

    International Nuclear Information System (INIS)

    Tip loss correction is known to play an important role for engineering prediction of wind turbine performance. There are two different types of tip loss corrections: tip corrections on momentum theory and tip corrections on airfoil data. In this paper, we study the latter using detailed CFD computations for wind turbines with sharp tip. Using the technique of determination of angle of attack and the CFD results for a NordTank 500 kW rotor, airfoil data are extracted and a new tip loss function on airfoil data is derived. To validate, BEM computations with the new tip loss function are carried out and compared with CFD results for the NordTank 500 kW turbine and the NREL 5 MW turbine. Comparisons show that BEM with the new tip loss function can predict correctly the loading near the blade tip

  3. Investigation of Unsteady Flow Field in a Low-Speed One and a Half Stage Axial Compressor. Part 2; Effects of Tip Gap Size On the Tip Clearance Flow Structure at Near Stall Operation

    Science.gov (United States)

    Hah, Chunill; Hathaway, Michael; Katz, Joseph

    2014-01-01

    The primary focus of this paper is to investigate the effect of rotor tip gap size on how the rotor unsteady tip clearance flow structure changes in a low speed one and half stage axial compressor at near stall operation (for example, where maximum pressure rise is obtained). A Large Eddy Simulation (LES) is applied to calculate the unsteady flow field at this flow condition with both a small and a large tip gaps. The numerically obtained flow fields at the small clearance matches fairly well with the available initial measurements obtained at the Johns Hopkins University with 3-D unsteady PIV in an index-matched test facility which renders the compressor blades and casing optically transparent. With this setup, the unsteady velocity field in the entire flow domain, including the flow inside the tip gap, can be measured. The numerical results are also compared with previously published measurements in a low speed single stage compressor (Maerz et al. [2002]). The current study shows that, with the smaller rotor tip gap, the tip clearance vortex moves to the leading edge plane at near stall operating condition, creating a nearly circumferentially aligned vortex that persists around the entire rotor. On the other hand, with a large tip gap, the clearance vortex stays inside the blade passage at near stall operation. With the large tip gap, flow instability and related large pressure fluctuation at the leading edge are observed in this one and a half stage compressor. Detailed examination of the unsteady flow structure in this compressor stage reveals that the flow instability is due to shed vortices near the leading edge, and not due to a three-dimensional separation vortex originating from the suction side of the blade, which is commonly referred to during a spike-type stall inception. The entire tip clearance flow is highly unsteady. Many vortex structures in the tip clearance flow, including the sheet vortex system near the casing, interact with each other. The

  4. Inheritance of Ear Tip-Barrenness Trait in Maize

    Institute of Scientific and Technical Information of China (English)

    MENG Zhao-dong; ZHANG Fa-jun; DING Zhao-hua; SUN Qi; WANG Li-ming; GUO Qing-fa; WANG Hong-gang

    2007-01-01

    The aim of this paper is to study the inheritance pattern of ear tip-barrenness trait in maize (Zea mays L.). Ear tipbarrenness trait in maize can be classified into two types, tip-barren and tip-barrenless. Two inbred lines, Ix01-3 (tipbarrenless type), wx04-1 (tip-barren type), and their F1, F2, BC1, BC2 generations were analyzed on their ear tip-barrenness types. Results showed that F1 was tip-barren type; the ratio of tip-barren type versus tip-barrenless type followed a 12.78∶1 ratio in F2 segregation population and a 2.75∶1 ratio in BC1. χ2 test indicated that the trait of ear tip-barrenness type followed an inheritance pattern of 2 duplicate dominant genes. SPSS analysis indicated that the trait of ear tip-barrenness length is of abnormal distribution. Above results mean that: (1) The trait of maize ear tip-barrenness type is controlled by2 duplicate dominant genes; tip-barren type is dominant over tip-barrenless type; (2) the trait of tip-barrenness length is a quantitative character controlled by polygene with major genes expected.

  5. Effect of TIPS placement on portal and splanchnic arterial blood flow in 4-dimensional flow MRI

    Energy Technology Data Exchange (ETDEWEB)

    Stankovic, Zoran [Northwestern University, Department of Radiology, Feinberg School of Medicine, Chicago, IL (United States); University Medical Center Freiburg, Department of Diagnostic Radiology and Medical Physics, Freiburg (Germany); Roessle, Martin; Schultheiss, Michael [University Medical Center Freiburg, Department of Gastroenterology, Freiburg (Germany); Euringer, Wulf; Langer, Mathias [University Medical Center Freiburg, Department of Diagnostic Radiology and Medical Physics, Freiburg (Germany); Salem, Riad; Barker, Alex; Carr, James; Collins, Jeremy D. [Northwestern University, Department of Radiology, Feinberg School of Medicine, Chicago, IL (United States); Markl, Michael [Northwestern University, Department of Radiology, Feinberg School of Medicine, Chicago, IL (United States); Northwestern University, Department of Biomedical Engineering, McCormick School of Engineering, Chicago, IL (United States)

    2015-09-15

    To assess changes in portal and splanchnic arterial haemodynamics in patients undergoing transjugular intrahepatic portosystemic shunt (TIPS) using four-dimensional (4D) flow MRI, a non-invasive, non-contrast imaging technique. Eleven patients undergoing TIPS implantation were enrolled. K-t GRAPPA accelerated non-contrast 4D flow MRI of the liver vasculature was applied with acceleration factor R = 5 at 3Tesla. Flow analysis included three-dimensional (3D) blood flow visualization using time-resolved 3D particle traces and semi-quantitative flow pattern grading. Quantitative evaluation entailed peak velocities and net flows throughout the arterial and portal venous (PV) systems. MRI measurements were taken within 24 h before and 4 weeks after TIPS placement. Three-dimensional flow visualization with 4D flow MRI revealed good image quality with minor limitations in PV flow. Quantitative analysis revealed a significant increase in PV flow (562 ± 373 ml/min before vs. 1831 ± 965 ml/min after TIPS), in the hepatic artery (176 ± 132 ml/min vs. 354 ± 140 ml/min) and combined flow in splenic and superior mesenteric arteries (770 ml/min vs. 1064 ml/min). Shunt-flow assessment demonstrated stenoses in two patients confirmed and treated at TIPS revision. Four-dimensional flow MRI might have the potential to give new information about the effect of TIPS placement on hepatic perfusion. It may explain some unexpected findings in clinical observation studies. (orig.)

  6. Effect of TIPS placement on portal and splanchnic arterial blood flow in 4-dimensional flow MRI

    International Nuclear Information System (INIS)

    To assess changes in portal and splanchnic arterial haemodynamics in patients undergoing transjugular intrahepatic portosystemic shunt (TIPS) using four-dimensional (4D) flow MRI, a non-invasive, non-contrast imaging technique. Eleven patients undergoing TIPS implantation were enrolled. K-t GRAPPA accelerated non-contrast 4D flow MRI of the liver vasculature was applied with acceleration factor R = 5 at 3Tesla. Flow analysis included three-dimensional (3D) blood flow visualization using time-resolved 3D particle traces and semi-quantitative flow pattern grading. Quantitative evaluation entailed peak velocities and net flows throughout the arterial and portal venous (PV) systems. MRI measurements were taken within 24 h before and 4 weeks after TIPS placement. Three-dimensional flow visualization with 4D flow MRI revealed good image quality with minor limitations in PV flow. Quantitative analysis revealed a significant increase in PV flow (562 ± 373 ml/min before vs. 1831 ± 965 ml/min after TIPS), in the hepatic artery (176 ± 132 ml/min vs. 354 ± 140 ml/min) and combined flow in splenic and superior mesenteric arteries (770 ml/min vs. 1064 ml/min). Shunt-flow assessment demonstrated stenoses in two patients confirmed and treated at TIPS revision. Four-dimensional flow MRI might have the potential to give new information about the effect of TIPS placement on hepatic perfusion. It may explain some unexpected findings in clinical observation studies. (orig.)

  7. Collaborative writing: Tools and tips

    Directory of Open Access Journals (Sweden)

    Eapen Bell

    2007-01-01

    Full Text Available Majority of technical writing is done by groups of experts and various web based applications have made this collaboration easy. Email exchange of word processor documents with tracked changes used to be the standard technique for collaborative writing. However web based tools like Google docs and Spreadsheets have made the process fast and efficient. Various versioning tools and synchronous editors are available for those who need additional functionality. Having a group leader who decides the scheduling, communication and conflict resolving protocols is important for successful collaboration.

  8. The tip of the iceberg

    DEFF Research Database (Denmark)

    Bjørst, Lill Rastad

    2010-01-01

    to the 2009 United Nations Climate Change Conference (COP15) in Copenhagen. The author argues that even though the discussions often seem to be centred on ice alone, the latter gets inscribed in narratives and metaphors which have wider implications for how the Arctic and its Indigenous peoples...... are represented. Ice becomes a nonhuman actor, framing the discussions, acting in specific ways, and linking hybrid networks. Indeed it is used in diverse platforms by scientists, politicians, governments, NGOs, as well as Inuit hunters and fishermen...

  9. Photoemission and photo-field-emission from photocathodes with arrays of silicon tips under continuous and pulsed lasers action; Photoemission et photoemission de champ a partir de photocathodes a reseaux de pointes de silicium sous l`action de lasers continus et pulses

    Energy Technology Data Exchange (ETDEWEB)

    Laguna, M.

    1995-11-01

    The electron machines`s development and improvement go through the discovery of new electron sources of high brightness. After reminding the interests in studying silicon cathodes with array of tips as electron sources, I describe, in the three steps model, the main phenomenological features related to photoemission and photoemission and photo-field-emission from a semi-conductor. the experimental set-ups used for the measurements reported in chapter four, five and six are described in chapter three. In chapter three. In chapter four several aspects of photo-field-emission in continuous and nanosecond regimes, studied on the Clermont-Ferrand`s test bench are tackled. We have measured quantum efficacies of 0.4 percent in the red (1.96 eV). Temporal responses in the nanoseconds range (10 ns) were observed with the Nd: YLF laser. With the laser impinging at an oblique angle we obtained ratios of photocurrent to dark current of the order of twenty. The issue of the high energy extracted photocurrent saturation is addressed and I give a preliminary explanation. In collaboration with the L.A.L. (Laboratoire de l`Accelerateur Lineaire) some tests with shortened pulsed laser beam (Nd: YAG laser 35 ps) were performed. Satisfactory response times have been obtained within the limitation of the scope (400 ps). (authors). 101 refs. 93 figs., 27 tabs., 3 photos., 1 append.

  10. Experimental Investigation of Factors Influencing Operating Rotor Tip Clearance in Multistage Compressors

    Directory of Open Access Journals (Sweden)

    Reid A. Berdanier

    2015-01-01

    Full Text Available An analysis of compressor rotor tip clearance measurements using capacitance probe instrumentation is discussed for a three-stage axial compressor. Thermal variations and centrifugal effects related to rotational speed changes affect clearance heights relative to the assembled configuration. These two primary contributions to measured changes are discussed both independently and in combination. Emphasis is given to tip clearance changes due to changing loading condition and at several compressor operating speeds. Measurements show a tip clearance change approaching 0.1 mm (0.2% rotor span when comparing a near-choke operating condition to a near-stall operating condition for the third stage. Additional consideration is given to environmental contributions such as ambient temperature, for which changes in tip clearance height on the order of 0.05 mm (0.1% rotor span were noted for temperature variations of 15°C. Experimental compressor operating clearances are presented for several temperatures, operating speeds, and loading conditions, and comparisons are drawn between these measured variations and predicted changes under the same conditions.

  11. Preparation of platinum/iridium scanning probe microscopy tips

    DEFF Research Database (Denmark)

    Sørensen, Alexis Hammer; Hvid, U.; Mortensen, M.W.;

    1999-01-01

    We report on the development of an etching setup for use in the preparation of platinum/iridium tips for atomic force microscopy and scanning electrostatic force microscopy as well as scanning tunneling microscopy. The etching process is based on a two step electrochemical procedure. The first step...... for the production of sharp tips. After being etched the tips are ready for use in scanning tunneling microscopes, or they may be bent to form integrated tip/cantilever systems in ordinary commercial atomic force microscopes, being applicable as tapping mode tips and as electrostatic force microscopy tips. ©1999...

  12. Validation of Tip Corrections for Wind Turbine computations

    DEFF Research Database (Denmark)

    Shen, Wen Zhong; Mikkelsen, Robert; Sørensen, Jens Nørkær;

    2003-01-01

    , these classical models fail to predict the physical behaviour.A new tip correction model is proposed.Comparisons between numerical and experimental data for flows past the NREL combined experiment rotor and the Swedish WG 500 rotor show that only the new model can predict correctly the force in the tip region.......Tip loss effect of rotors plays an important role in predictions of wind turbine performance. Classical tip corrections, based on the Prandtl tip reduction function, including Glauert´, Wilson & Lissaman´s and De Vries´ corrections are considered in the paper. In the proximity of the tip...

  13. A refined tip correction based on decambering

    DEFF Research Database (Denmark)

    Sørensen, Jens Nørkær; Dag, Kaya Onur; Ramos García, Néstor

    2016-01-01

    A new tip correction for use in performance codes based on the blade element momentum (BEM) or the lifting-line techniqueis presented. The correction modifies the circulation by taking into account the additional influence of the inductionof the vortices in the wake, using the so-called decamberi...

  14. Vertically aligned nanostructure scanning probe microscope tips

    Science.gov (United States)

    Guillorn, Michael A.; Ilic, Bojan; Melechko, Anatoli V.; Merkulov, Vladimir I.; Lowndes, Douglas H.; Simpson, Michael L.

    2006-12-19

    Methods and apparatus are described for cantilever structures that include a vertically aligned nanostructure, especially vertically aligned carbon nanofiber scanning probe microscope tips. An apparatus includes a cantilever structure including a substrate including a cantilever body, that optionally includes a doped layer, and a vertically aligned nanostructure coupled to the cantilever body.

  15. Tip cells: master regulators of tubulogenesis?

    Science.gov (United States)

    Weavers, Helen; Skaer, Helen

    2014-07-01

    The normal development of an organ depends on the coordinated regulation of multiple cell activities. Focusing on tubulogenesis, we review the role of specialised cells or groups of cells that are selected from within tissue primordia and differentiate at the outgrowing tips or leading edge of developing tubules. Tip or leading cells develop distinctive patterns of gene expression that enable them to act both as sensors and transmitters of intercellular signalling. This enables them to explore the environment, respond to both tissue intrinsic signals and extrinsic cues from surrounding tissues and to regulate the behaviour of their neighbours, including the setting of cell fate, patterning cell division, inducing polarity and promoting cell movement and cell rearrangements by neighbour exchange. Tip cells are also able to transmit mechanical tension to promote tissue remodelling and, by interacting with the extracellular matrix, they can dictate migratory pathways and organ shape. Where separate tubular structures fuse to form networks, as in the airways of insects or the vascular system of vertebrates, specialised fusion tip cells act to interconnect disparate elements of the developing network. Finally, we consider their importance in the maturation of mature physiological function and in the development of disease.

  16. SEVEN TIPS FOR TEACHING YOUNG LEARNERS ENGLISH

    Institute of Scientific and Technical Information of China (English)

    Yang; Mingguang

    2001-01-01

    Young Learners English (YLE) teaching program is goingto be very popular in China. Although all the YLE teachers usean English textbook, there are some basic aspects concerningYLE teaching which are worth the attention of YLE teachersbecause teaching children is quite different from teaching middleschool students and adults. This paper discusses these importantaspects, gives some examples and shows seven tips for teachingpractice.

  17. Microtubules guide root hair tip growth

    NARCIS (Netherlands)

    Sieberer, B.; Ketelaar, M.J.; Esseling, J.J.; Emons, A.M.C.

    2005-01-01

    The ability to establish cell polarity is crucial to form and function of an individual cell. Polarity underlies critical processes during cell development, such as cell growth, cell division, cell differentiation and cell signalling. Interphase cytoplasmic microtubules in tip-growing fission yeast

  18. 10 Tips for an Outstanding Children's Collection.

    Science.gov (United States)

    Colburn, Nell

    1994-01-01

    Gives 10 essential tips for building children's collections, including using a systematic spending plan; applying circulation figures; making replacement purchases a priority; getting more copies and fewer titles; allocating funds for popular paperbacks; buying paperback fiction; seeking basic skills materials; taking advantage of vendor services;…

  19. Note: electrochemical etching of sharp iridium tips.

    Science.gov (United States)

    Lalanne, Jean-Benoît; Paul, William; Oliver, David; Grütter, Peter H

    2011-11-01

    We describe an etching procedure for the production of sharp iridium tips with apex radii of 15-70 nm, as determined by scanning electron microscopy, field ion microscopy, and field emission measurements. A coarse electrochemical etch followed by zone electropolishing is performed in a relatively harmless calcium chloride solution with high success rate.

  20. Next Stop Adulthood: Tips for Parents

    Science.gov (United States)

    ... Dating & Sex Fitness Nutrition Driving Safety School Substance Abuse Young Adult Healthy Children > Ages & Stages > Teen > Next Stop Adulthood: Tips For ... seen as a source of ready cash, your child has no incentive to handle money responsibly. Decide on a fair amount, and discuss ...