WorldWideScience

Sample records for bottom-up saliency mediates

  1. Predicting Saliency and Aesthetics in Images: A Bottom-up Perspective

    OpenAIRE

    Murray, Naila

    2012-01-01

    Esta tesis investiga dos aspectos diferentes sobre cómo un observador percibe una imagen natural: (i) dónde miramos o, concretamente, qué nos atrae la atención, y (ii) qué nos gusta, e.g., si una imagen es estéticamente agradable, o no. Estas dos experiencias son objeto de crecientes esfuerzos de la investigación en visión por computador. Tanto la atención visual como la estética visual pueden ser modeladas como consecuencia de múltiples mecanismos en interacción, algunos bottom-up o involunt...

  2. Modeling eye movements in visual agnosia with a saliency map approach: bottom-up guidance or top-down strategy?

    Science.gov (United States)

    Foulsham, Tom; Barton, Jason J S; Kingstone, Alan; Dewhurst, Richard; Underwood, Geoffrey

    2011-08-01

    Two recent papers (Foulsham, Barton, Kingstone, Dewhurst, & Underwood, 2009; Mannan, Kennard, & Husain, 2009) report that neuropsychological patients with a profound object recognition problem (visual agnosic subjects) show differences from healthy observers in the way their eye movements are controlled when looking at images. The interpretation of these papers is that eye movements can be modeled as the selection of points on a saliency map, and that agnosic subjects show an increased reliance on visual saliency, i.e., brightness and contrast in low-level stimulus features. Here we review this approach and present new data from our own experiments with an agnosic patient that quantifies the relationship between saliency and fixation location. In addition, we consider whether the perceptual difficulties of individual patients might be modeled by selectively weighting the different features involved in a saliency map. Our data indicate that saliency is not always a good predictor of fixation in agnosia: even for our agnosic subject, as for normal observers, the saliency-fixation relationship varied as a function of the task. This means that top-down processes still have a significant effect on the earliest stages of scanning in the setting of visual agnosia, indicating severe limitations for the saliency map model. Top-down, active strategies-which are the hallmark of our human visual system-play a vital role in eye movement control, whether we know what we are looking at or not. Copyright © 2011 Elsevier Ltd. All rights reserved.

  3. Bottom-up and trait-mediated effects of resource quality on amphibian parasitism.

    Science.gov (United States)

    Stephens, Jeffrey P; Altman, Karie A; Berven, Keith A; Tiegs, Scott D; Raffel, Thomas R

    2017-03-01

    Leaf litter subsidies are important resources for aquatic consumers like tadpoles and snails, causing bottom-up effects on wetland ecosystems. Recent studies have shown that variation in litter nutritional quality can be as important as litter quantity in driving these bottom-up effects. Resource subsidies likely also have indirect and trait-mediated effects on predation and parasitism, but these potential effects remain largely unexplored. We generated predictions for differential effects of litter nutrition and secondary polyphenolic compounds on tadpole (Lithobates sylvatica) exposure and susceptibility to Ribeiroia ondatrae, based on ecological stoichiometry and community-ecology theory. We predicted direct and indirect effects on key traits of the tadpole host (rates of growth, development and survival), the trematode parasite (production of the cercaria infective stages) and the parasite's snail intermediate host (growth and reproduction). To test these predictions, we conducted a large-scale mesocosm experiment using a natural gradient in the concentrations of nutrients (nitrogen) and toxic secondary compounds (polyphenolics) of nine leaf litter species. To differentiate between effects on exposure vs. susceptibility to infection, we included multiple infection experiments including one with constant per capita exposure. We found that increased litter nitrogen increased tadpole survival, and also increased cercaria production by the snail intermediate hosts, causing opposing effects on tadpole per capita exposure to trematode infection. Increased litter polyphenolics slowed tadpole development, leading to increased infection by increasing both their susceptibility to infection and the length of time they were exposed to parasites. Based on these results, recent shifts in forest composition towards more nitrogen-poor litter species should decrease trematode infection in tadpoles via density- and trait-mediated effects on the snail intermediate hosts. However

  4. Within-plant bottom-up effects mediate non-consumptive impacts of top-down control of soybean aphids.

    Directory of Open Access Journals (Sweden)

    Alejandro C Costamagna

    Full Text Available There is increasing evidence that top-down controls have strong non-consumptive effects on herbivore populations. However, little is known about how these non-consumptive effects relate to bottom-up influences. Using a series of field trials, we tested how changes in top-down and bottom-up controls at the within-plant scale interact to increase herbivore suppression. In the first experiment, we manipulated access of natural populations of predators (primarily lady beetles to controlled numbers of A. glycines on upper (i.e. vigorous-growing versus lower (i.e. slow-growing soybean nodes and under contrasting plant ages. In a second experiment, we measured aphid dispersion in response to predation. Bottom-up and top-down controls had additive effects on A. glycines population growth. Plant age and within-plant quality had significant bottom-up effects on aphid size and population growth. However, top-down control was the dominant force suppressing aphid population growth, and completely counteracted bottom-up effects at the plant and within-plant scales. The intensity of predation was higher on upper than lower soybean nodes, and resulted in a non-consumptive reduction in aphid population growth because most of the surviving aphids were located on lower plant nodes, where rates of increase were reduced. No effects of predation on aphid dispersal among plants were detected, suggesting an absence of predator avoidance behavior by A. glycines. Our results revealed significant non-consumptive predator impacts on aphids due to the asymmetric intensity of predation at the within-plant scale, suggesting that low numbers of predators are highly effective at suppressing aphid populations.

  5. Investigating bottom-up auditory attention

    Directory of Open Access Journals (Sweden)

    Emine Merve Kaya

    2014-05-01

    Full Text Available Bottom-up attention is a sensory-driven selection mechanism that directs perception towards a subset of the stimulus that is considered salient, or attention-grabbing. Most studies of bottom-up auditory attention have adapted frameworks similar to visual attention models whereby local or global contrast is a central concept in defining salient elements in a scene. In the current study, we take a more fundamental approach to modeling auditory attention; providing the first examination of the space of auditory saliency spanning pitch, intensity and timbre; and shedding light on complex interactions among these features. Informed by psychoacoustic results, we develop a computational model of auditory saliency implementing a novel attentional framework, guided by processes hypothesized to take place in the auditory pathway. In particular, the model tests the hypothesis that perception tracks the evolution of sound events in a multidimensional feature space, and flags any deviation from background statistics as salient. Predictions from the model corroborate the relationship between bottom-up auditory attention and statistical inference, and argues for a potential role of predictive coding as mechanism for saliency detection in acoustic scenes.

  6. Community biomass and bottom up multivariate nutrient complementarity mediate the effects of bioturbator diversity on pelagic production.

    Directory of Open Access Journals (Sweden)

    Adriano Caliman

    Full Text Available Tests of the biodiversity and ecosystem functioning (BEF relationship have focused little attention on the importance of interactions between species diversity and other attributes of ecological communities such as community biomass. Moreover, BEF research has been mainly derived from studies measuring a single ecosystem process that often represents resource consumption within a given habitat. Focus on single processes has prevented us from exploring the characteristics of ecosystem processes that can be critical in helping us to identify how novel pathways throughout BEF mechanisms may operate. Here, we investigated whether and how the effects of biodiversity mediated by non-trophic interactions among benthic bioturbator species vary according to community biomass and ecosystem processes. We hypothesized that (1 bioturbator biomass and species richness interact to affect the rates of benthic nutrient regeneration [dissolved inorganic nitrogen (DIN and total dissolved phosphorus (TDP] and consequently bacterioplankton production (BP and that (2 the complementarity effects of diversity will be stronger on BP than on nutrient regeneration because the former represents a more integrative process that can be mediated by multivariate nutrient complementarity. We show that the effects of bioturbator diversity on nutrient regeneration increased BP via multivariate nutrient complementarity. Consistent with our prediction, the complementarity effects were significantly stronger on BP than on DIN and TDP. The effects of the biomass-species richness interaction on complementarity varied among the individual processes, but the aggregated measures of complementarity over all ecosystem processes were significantly higher at the highest community biomass level. Our results suggest that the complementarity effects of biodiversity can be stronger on more integrative ecosystem processes, which integrate subsidiary "simpler" processes, via multivariate

  7. Nanoelectronics from the bottom up.

    Science.gov (United States)

    Lu, Wei; Lieber, Charles M

    2007-11-01

    Electronics obtained through the bottom-up approach of molecular-level control of material composition and structure may lead to devices and fabrication strategies not possible with top-down methods. This review presents a brief summary of bottom-up and hybrid bottom-up/top-down strategies for nanoelectronics with an emphasis on memories based on the crossbar motif. First, we will discuss representative electromechanical and resistance-change memory devices based on carbon nanotube and core-shell nanowire structures, respectively. These device structures show robust switching, promising performance metrics and the potential for terabit-scale density. Second, we will review architectures being developed for circuit-level integration, hybrid crossbar/CMOS circuits and array-based systems, including experimental demonstrations of key concepts such lithography-independent, chemically coded stochastic demultipluxers. Finally, bottom-up fabrication approaches, including the opportunity for assembly of three-dimensional, vertically integrated multifunctional circuits, will be critically discussed.

  8. Culture from the Bottom Up

    Science.gov (United States)

    Atkinson, Dwight; Sohn, Jija

    2013-01-01

    The culture concept has been severely criticized for its top-down nature in TESOL, leading arguably to its falling out of favor in the field. But what of the fact that people do "live culturally" (Ingold, 1994)? This article describes a case study of culture from the bottom up--culture as understood and enacted by its individual users.…

  9. Bottom-up effects on attention capture and choice

    DEFF Research Database (Denmark)

    Peschel, Anne; Orquin, Jacob Lund; Mueller Loose, Simone

    of different product categories. Surface size and visual saliency of a product label were manipulated to determine bottom-up effects on attention and choice. Results show a strong and significant increase in attention in terms of fixation likelihood towards product labels which are larger and more visually...... the information available to form a decision. Does changing one visual cue in the stimulus set affect attention towards this cue and what does that mean for the choice outcome? To address this, we conducted a combined eye tracking and choice experiment in a consumer choice setting with visual shelf simulations...

  10. Density- and trait-mediated top-down effects modify bottom-up control of a highly endemic tropical aquatic food web

    Science.gov (United States)

    C. M. Dalton; A. Mokiao-Lee; T. S. Sakihara; M. G. Weber; C. A. Roco; Z. Han; B. Dudley; R. A. MacKenzie; N. G. Hairston Jr.

    2013-01-01

    Benthic invertebrates mediate bottom–up and top–down influences in aquatic food webs, and changes in the abundance or traits of invertebrates can alter the strength of top–down effects. Studies assessing the role of invertebrate abundance and behavior as controls on food web structure are rare at the whole ecosystem scale. Here we use a comparative approach to...

  11. Top-Down Beta Enhances Bottom-Up Gamma.

    Science.gov (United States)

    Richter, Craig G; Thompson, William H; Bosman, Conrado A; Fries, Pascal

    2017-07-12

    Several recent studies have demonstrated that the bottom-up signaling of a visual stimulus is subserved by interareal gamma-band synchronization, whereas top-down influences are mediated by alpha-beta band synchronization. These processes may implement top-down control of stimulus processing if top-down and bottom-up mediating rhythms are coupled via cross-frequency interaction. To test this possibility, we investigated Granger-causal influences among awake macaque primary visual area V1, higher visual area V4, and parietal control area 7a during attentional task performance. Top-down 7a-to-V1 beta-band influences enhanced visually driven V1-to-V4 gamma-band influences. This enhancement was spatially specific and largest when beta-band activity preceded gamma-band activity by ∼0.1 s, suggesting a causal effect of top-down processes on bottom-up processes. We propose that this cross-frequency interaction mechanistically subserves the attentional control of stimulus selection.SIGNIFICANCE STATEMENT Contemporary research indicates that the alpha-beta frequency band underlies top-down control, whereas the gamma-band mediates bottom-up stimulus processing. This arrangement inspires an attractive hypothesis, which posits that top-down beta-band influences directly modulate bottom-up gamma band influences via cross-frequency interaction. We evaluate this hypothesis determining that beta-band top-down influences from parietal area 7a to visual area V1 are correlated with bottom-up gamma frequency influences from V1 to area V4, in a spatially specific manner, and that this correlation is maximal when top-down activity precedes bottom-up activity. These results show that for top-down processes such as spatial attention, elevated top-down beta-band influences directly enhance feedforward stimulus-induced gamma-band processing, leading to enhancement of the selected stimulus. Copyright © 2017 Richter, Thompson et al.

  12. Where to start? Bottom-up attention improves working memory by determining encoding order.

    Science.gov (United States)

    Ravizza, Susan M; Uitvlugt, Mitchell G; Hazeltine, Eliot

    2016-12-01

    The present study aimed to characterize the mechanism by which working memory is enhanced for items that capture attention because of their novelty or saliency-that is, via bottom-up attention. The first experiment replicated previous research by corroborating that bottom-up attention directed to an item is sufficient for enhancing working memory and, moreover, generalized the effect to the domain of verbal working memory. The subsequent 3 experiments sought to determine how bottom-up attention affects working memory. We considered 2 hypotheses: (1) Bottom-up attention enhances the encoded representation of the stimulus, similar to how voluntary attention functions, or (2) It affects the order of encoding by shifting priority onto the attended stimulus. By manipulating how stimuli were presented (simultaneous/sequential display) and whether the cue predicted the tested items, we found evidence that bottom-up attention improves working memory performance via the order of encoding hypothesis. This finding was observed across change detection and free recall paradigms. In contrast, voluntary attention improved working memory regardless of encoding order and showed greater effects on working memory. We conclude that when multiple information sources compete, bottom-up attention prioritizes the location at which encoding should begin. When encoding order is set, bottom-up attention has little or no benefit to working memory. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

  13. Police reform from the bottom up

    African Journals Online (AJOL)

    The title of this volume, Police reform from the bottom up, is bound to create expectations amongst those concerned with the challenges confronting institutional change in public police agencies. It is an interest shared by police scholars and practitioners across the usual North-South divide. Few police agencies today can ...

  14. Emergence of visual saliency from natural scenes via context-mediated probability distributions coding.

    Directory of Open Access Journals (Sweden)

    Jinhua Xu

    Full Text Available Visual saliency is the perceptual quality that makes some items in visual scenes stand out from their immediate contexts. Visual saliency plays important roles in natural vision in that saliency can direct eye movements, deploy attention, and facilitate tasks like object detection and scene understanding. A central unsolved issue is: What features should be encoded in the early visual cortex for detecting salient features in natural scenes? To explore this important issue, we propose a hypothesis that visual saliency is based on efficient encoding of the probability distributions (PDs of visual variables in specific contexts in natural scenes, referred to as context-mediated PDs in natural scenes. In this concept, computational units in the model of the early visual system do not act as feature detectors but rather as estimators of the context-mediated PDs of a full range of visual variables in natural scenes, which directly give rise to a measure of visual saliency of any input stimulus. To test this hypothesis, we developed a model of the context-mediated PDs in natural scenes using a modified algorithm for independent component analysis (ICA and derived a measure of visual saliency based on these PDs estimated from a set of natural scenes. We demonstrated that visual saliency based on the context-mediated PDs in natural scenes effectively predicts human gaze in free-viewing of both static and dynamic natural scenes. This study suggests that the computation based on the context-mediated PDs of visual variables in natural scenes may underlie the neural mechanism in the early visual cortex for detecting salient features in natural scenes.

  15. Information theoretic preattentive saliency

    DEFF Research Database (Denmark)

    Loog, Marco

    2011-01-01

    Employing an information theoretic operational definition of bottom-up attention from the field of computational visual perception a very general expression for saliency is provided. As opposed to many of the current approaches to determining a saliency map there is no need for an explicit data...... of which features, image information is described. We illustrate our result by determining a few specific saliency maps based on particular choices of features. One of them makes the link with the mapping underlying well-known Harris interest points, which is a result recently obtained in isolation...

  16. The benefits of bottom-up design

    Science.gov (United States)

    Mcfarland, Gregory

    1986-01-01

    An inconsistency is examined in generic top-down design methods and standards employed in the implementation of reliable software. Many design approaches adopt top-down ordering when defining the structure, interfaces, and processing of a system. However, strict adherence to a top-down sequencing does not permit accurate description of a system's error handling functions. The design of the system response to errors is becoming critical as the reliability requirements of systems increase. How top-down methods such as object oriented design and structured design do not adequately address the issues of error handling is described, and it is suggested using a bottom-up substep within these methods to eliminate the problem.

  17. On the Temporal Relation of Top-Down and Bottom-Up Mechanisms during Guidance of Attention

    Science.gov (United States)

    Wykowska, Agnieszka; Schubo, Anna

    2010-01-01

    Two mechanisms are said to be responsible for guiding focal attention in visual selection: bottom-up, saliency-driven capture and top-down control. These mechanisms were examined with a paradigm that combined a visual search task with postdisplay probe detection. Two SOAs between the search display and probe onsets were introduced to investigate…

  18. A Clash of Bottom-Up and Top-Down Processes in Visual Search: The Reversed Letter Effect Revisited

    Science.gov (United States)

    Zhaoping, Li; Frith, Uta

    2011-01-01

    It is harder to find the letter "N" among its mirror reversals than vice versa, an inconvenient finding for bottom-up saliency accounts based on primary visual cortex (V1) mechanisms. However, in line with this account, we found that in dense search arrays, gaze first landed on either target equally fast. Remarkably, after first landing,…

  19. Bottom-up grammar analysis : a functional formulation

    NARCIS (Netherlands)

    Jeuring, J.T.; Swierstra, D.

    1994-01-01

    This paper discusses bottom-up grammar analysis problems such as te EMPTY problem and the FIRST problem. It defines a general class of bottom-up grammar analysis problems, and from this definition it derives a functional program for performing bottom-up grammar analysis. The derivation is purely

  20. Join me in Death: Managing Mortality Salience via Mediated Social Encounters

    OpenAIRE

    Frischlich, Lena

    2015-01-01

    The synopsis of this cumulative dissertation reports the theoretical background, methodology and main results of five studies addressing the role of intergroup versus interpersonal similarities for mediated social encounters under conditions of mortality salience (MS). Drawing upon terror management theory (TMT, Greenberg, Pyszczynski, & Solomon, 1986) individuals were expected to prefer similar over dissimilar others under conditions of MS. In theory, similarity can take place on the intergr...

  1. Bottoms Up. [report on the Defense Department

    Energy Technology Data Exchange (ETDEWEB)

    Isaacs, J.

    1993-11-01

    The [open quotes]Bottoms Up Review[close quotes] was the Pentagon's ongoing reevaluation of the dangers faced by the United States and the forces needed to deal with those dangers. Its purpose was [open quotes]to define the strategy, force structure, modernization programs, industrial base, and infrastucture needed to meet new dangers and seize new opportunities.[close quotes] The report was released in early September. Washington's reaction to the review (generally silence) and the review's major shortcomings are discussed is this article. The central shortfall of the review is the disconnection between the latest military plan and the security threats faced by the United States. As an example of the disconnection, the Pentagon's fiscal 1994 budget request allots less than one percent of the $263 billion budget request to destroy nuclear weapons in the former Soviet Union, to fund peacekeeping operations, to support economic conversion, and to counter proliferation, although these problems are among those slated as among the most important when listed in the review.

  2. Measuring Object Salience

    Directory of Open Access Journals (Sweden)

    A.D.F Clarke

    2014-08-01

    Full Text Available Over the past 15 years work on visual salience has been restricted to models of low-level, bottom-up salience that give an estimate of the salience for every pixel in an image. This study concerns the question of how to measure the salience of objects: given an image and a list of areas of interest (AOIs, can we assign salience scores to the AOIs that reflect their visual prominence? There is increasing evidence that fixations locations are best explained at an object level and an object-level notion of visual salience can easily be incorporated with other object features task relevance and concepts such as scene context. However, extracting scores for AOIs from the saliency maps output by existing models is a non-trivial task. Using simple psychophysical (1/f-noise stimuli, we demonstrate that simple methods for assigning salience score to AOIs (such as taking the maximum, mean, or sum of the relevant pixels in the salience map produce unintuitive results, such as predicting that larger objects are less salient. We also evaluate object salience models over a range of tasks and compare to empirical data. Beyond predicting the number of fixations to different objects in a scene, we also estimate the difficulty of visual search trials; and incorporate visual salience into language production tasks. We present a simple object-based salience model (based on comparing the likelihood of an AOI given the rest of the image to the likelihood of a typical patch of the same area] that gives intuitive results for the 1/f-noise stimuli and performs as well as existing methods on empirical datasets.

  3. Bottom-up grammar analysis : a functional formulation

    OpenAIRE

    Jeuring, J.T.; Swierstra, D.

    1994-01-01

    This paper discusses bottom-up grammar analysis problems such as te EMPTY problem and the FIRST problem. It defines a general class of bottom-up grammar analysis problems, and from this definition it derives a functional program for performing bottom-up grammar analysis. The derivation is purely calculational, using theorems from lattice therory, the Bird-Meertens calculus, and laws for list-comprehensions. Sufficient conditions guaranteeing the existence of a solution emerge as a byproduct o...

  4. A Proto-Object-Based Computational Model for Visual Saliency

    NARCIS (Netherlands)

    Yanulevskaya, V.; Uijlings, J.; Geusebroek, J.-M.; Sebe, N.; Smeulders, A.

    2013-01-01

    State-of-the-art bottom-up saliency models often assign high saliency values at or near high-contrast edges, whereas people tend to look within the regions delineated by those edges, namely the objects. To resolve this inconsistency, in this work we estimate saliency at the level of coherent image

  5. Bottom-up attention orienting in young children with autism.

    Science.gov (United States)

    Amso, Dima; Haas, Sara; Tenenbaum, Elena; Markant, Julie; Sheinkopf, Stephen J

    2014-03-01

    We examined the impact of simultaneous bottom-up visual influences and meaningful social stimuli on attention orienting in young children with autism spectrum disorders (ASDs). Relative to typically-developing age and sex matched participants, children with ASDs were more influenced by bottom-up visual scene information regardless of whether social stimuli and bottom-up scene properties were congruent or competing. This initial reliance on bottom-up strategies correlated with severity of social impairment as well as receptive language impairments. These data provide support for the idea that there is enhanced reliance on bottom-up attention strategies in ASDs, and that this may have a negative impact on social and language development.

  6. The Effect of Linguistic and Visual Salience in Visual World Studies

    Directory of Open Access Journals (Sweden)

    Federica eCavicchio

    2014-03-01

    Full Text Available Research using the visual world paradigm has demonstrated that visual input has a rapid effect on language interpretation tasks such as reference resolution and, conversely, that linguistic material—including verbs, prepositions and adjectives—can influence fixations to potential referents. More recent research has started to explore how this effect of linguistic input on fixations is mediated by properties of the visual stimulus, in particular by visual salience. In the present study we further explored the role of salience in the visual world paradigm manipulating language-driven salience and visual salience. Specifically, we tested how linguistic salience (i.e. the greater accessibility of linguistically introduced entities and visual salience (bottom-up attention grabbing visual aspects interact. We recorded participants’ eye-movements during a MapTask, asking them to look from landmark to landmark displayed upon a map while hearing direction-giving instructions. The landmarks were of comparable size and color, except in the Visual Salience condition, in which one landmark had been made more visually salient. In the Linguistic Salience conditions, the instructions included references to an object not on the map. Response times and fixations were recorded. Visual Salience influenced the time course of fixations at both the beginning and the end of the trial but did not show a significant effect on response times. Linguistic Salience reduced response times and increased fixations to landmarks when they were associated to a Linguistic Salient entity not present itself on the map. When the target landmark was both visualyl and linguistically salient, it was fixated longer, but fixations were quicker when the target item was linguistically salient only. Our results suggest that the two types of salience work in parallel and that linguistic salience affects fixations even when the entity is not visually present.

  7. Bottom-up Initiatives for Photovoltaic: Incentives and Barriers

    Directory of Open Access Journals (Sweden)

    Kathrin Reinsberger

    2014-06-01

    Full Text Available When facing the challenge of restructuring the energy system, bottom-up initiatives can aid the diffusion of decentralized and clean energy technologies. We focused here on a bottom-up initiative of citizen-funded and citizen-operated photovoltaic power plants. The project follows a case study-based approach and examines two different community initiatives. The aim is to investigate the potential incentives and barriers relating to participation or non-participation in predefined community PV projects. Qualitative, as well as quantitative empirical research was used to examine the key factors in the further development of bottom-up initiatives as contributors to a general energy transition.

  8. Stability of leadership in bottom-up hierarchical organizations

    OpenAIRE

    Galam, Serge

    2007-01-01

    The stability of a leadership against a growing internal opposition is studied in bottom-up hierarchical organizations. Using a very simple model with bottom-up majority rule voting, the dynamics of power distribution at the various hierarchical levels is calculated within a probabilistic framework. Given a leadership at the top, the opposition weight from the hierarchy bottom is shown to fall off quickly while climbing up the hierarchy. It reaches zero after only a few hierarchical levels. I...

  9. Event-Related Potentials of Bottom-Up and Top-Down Processing of Emotional Faces.

    Science.gov (United States)

    Moradi, Afsane; Mehrinejad, Seyed Abolghasem; Ghadiri, Mohammad; Rezaei, Farzin

    2017-01-01

    Emotional stimulus is processed automatically in a bottom-up way or can be processed voluntarily in a top-down way. Imaging studies have indicated that bottom-up and top-down processing are mediated through different neural systems. However, temporal differentiation of top-down versus bottom-up processing of facial emotional expressions has remained to be clarified. The present study aimed to explore the time course of these processes as indexed by the emotion-specific P100 and late positive potential (LPP) event-related potential (ERP) components in a group of healthy women. Fourteen female students of Alzahra University, Tehran, Iran aged 18-30 years, voluntarily participated in the study. The subjects completed 2 overt and covert emotional tasks during ERP acquisition. The results indicated that fearful expressions significantly produced greater P100 amplitude compared to other expressions. Moreover, the P100 findings showed an interaction between emotion and processing conditions. Further analysis indicated that within the overt condition, fearful expressions elicited more P100 amplitude compared to other emotional expressions. Also, overt conditions created significantly more LPP latencies and amplitudes compared to covert conditions. Based on the results, early perceptual processing of fearful face expressions is enhanced in top-down way compared to bottom-up way. It also suggests that P100 may reflect an attentional bias toward fearful emotions. However, no such differentiation was observed within later processing stages of face expressions, as indexed by the ERP LPP component, in a top-down versus bottom-up way. Overall, this study provides a basis for further exploring of bottom-up and top-down processes underlying emotion and may be typically helpful for investigating the temporal characteristics associated with impaired emotional processing in psychiatric disorders.

  10. Selecting category specific visual information: Top-down and bottom-up control of object based attention.

    Science.gov (United States)

    Corradi-Dell'Acqua, Corrado; Fink, Gereon R; Weidner, Ralph

    2015-09-01

    The ability to select, within the complexity of sensory input, the information most relevant for our purposes is influenced by both internal settings (i.e., top-down control) and salient features of external stimuli (i.e., bottom-up control). We here investigated using fMRI the neural underpinning of the interaction of top-down and bottom-up processes, as well as their effects on extrastriate areas processing visual stimuli in a category-selective fashion. We presented photos of bodies or buildings embedded into frequency-matched visual noise to the subjects. Stimulus saliency changed gradually due to an altered degree to which photos stood-out in relation to the surrounding noise (hence generating stronger bottom-up control signals). Top-down settings were manipulated via instruction: participants were asked to attend one stimulus category (i.e., "is there a body?" or "is there a building?"). Highly salient stimuli that were inconsistent with participants' attentional top-down template activated the inferior frontal junction and dorsal parietal regions bilaterally. Stimuli consistent with participants' current attentional set additionally activated insular cortex and the parietal operculum. Furthermore, the extrastriate body area (EBA) exhibited increased neural activity when attention was directed to bodies. However, the latter effect was found only when stimuli were presented at intermediate saliency levels, thus suggesting a top-down modulation of this region only in the presence of weak bottom-up signals. Taken together, our results highlight the role of the inferior frontal junction and posterior parietal regions in integrating bottom-up and top-down attentional control signals. Copyright © 2015 Elsevier Inc. All rights reserved.

  11. On a Bottom-Up Approach to Scientific Discovery

    Science.gov (United States)

    Huang, Xiang

    2014-03-01

    Two popular models of scientific discovery, abduction and the inference to the best explanation (IBE), presuppose that the reason for accepting a hypothetical explanation A comes from the epistemic and/or explanatory force manifested in the fact that observed fact C is an inferred consequence of A. However, not all discoveries take this top-down procedure from A to C, in which the result of discovery A implies the observed fact C. I contend that discovery can be modeled as a bottom-up procedure based on inductive and analogical rules that lead us to infer from C to A. I take the theory of Dignaga, an Indian medieval logician, as a model of this bottom-up approach. My argument has three panels: 1) this bottom-up approach applies to both commonsense and scientific discovery without the assumption that C has to be an inferred consequence of A; 2) this bottom-up approach helps us get around problems that crop up in applying abduction and/or IBE, which means that scientific discovery need not to be modeled exclusively by top-down approaches; and 3) the existence of the bottom-up approach requires a pluralist attitude towards modeling of scientific discovery.

  12. A plea for Global Health Action bottom-up

    Directory of Open Access Journals (Sweden)

    Ulrich Laaser

    2016-10-01

    Full Text Available This opinion piece focuses on global health action by hands-on bottom-up practice: Initiation of an organizational framework and securing financial efficiency are – however - essential, both clearly a domain of well trained public health professionals. Examples of action are cited in the four main areas of global threats: planetary climate change, global divides and inequity, global insecurity and violent conflicts, global instability and financial crises. In conclusion a stable health systems policy framework would greatly enhance success. However, such organisational framework dries out if not linked to public debates channelling fresh thoughts and controversial proposals: the structural stabilisation is essential but has to serve not to dominate bottom-up activities. In other words a horizontal management is required, a balanced equilibrium between bottom-up initiative and top-down support. Last not least rewarding voluntary and charity work by public acknowledgement is essential.

  13. Saliency detection based on manifold learning

    Science.gov (United States)

    Yang, Zhi; Li, DeHua; Wang, Jie; Li, Xuan

    2013-10-01

    Visual saliency has recently attracted lots of research interest in the computer vision community. In this paper, we propose a novel computational model for bottom-up saliency detection based on manifold learning. A typical graphbased manifold learning algorithm, namely the diffusion map, is adopted for establishing our saliency model. In the proposed method, firstly, a graph is constructed using low-level image features. Then, the diffusion map algorithm is performed to learn the diffusion distances, which are utilized to derive the saliency measure. Compared to existing saliency models, our method has the advantage of being able to capture the intrinsic nonlinear structures in the original feature space. Moreover, due to the inherent characteristics of the diffusion map algorithm, our method can deal with the multi-scale issue effectively, which is crucial to any saliency model. Experimental results on publicly available data demonstrate that our method outperforms the state-of-the-art saliency models, both qualitatively and quantitatively.

  14. Bottom-up synthetic biology: engineering in a tinkerer's world.

    Science.gov (United States)

    Schwille, Petra

    2011-09-02

    How synthetic can "synthetic biology" be? A literal interpretation of the name of this new life science discipline invokes expectations of the systematic construction of biological systems with cells being built module by module--from the bottom up. But can this possibly be achieved, taking into account the enormous complexity and redundancy of living systems, which distinguish them quite remarkably from design features that characterize human inventions? There are several recent developments in biology, in tight conjunction with quantitative disciplines, that may bring this literal perspective into the realm of the possible. However, such bottom-up engineering requires tools that were originally designed by nature's greatest tinkerer: evolution.

  15. Planning from the bottom up : Democratic decentralisation in action

    NARCIS (Netherlands)

    Pal, A.

    2010-01-01

    This research highlights the gap between the official rhetoric and the political reality of democratic decentralisation and bottom-up planning using an indepth study of the metropolitan planning process in Kolkata, India. The key question that I address here is: how do elected officials at different

  16. Fostering Rural Social Organizations: A Bottom-Up Paradigm In ...

    African Journals Online (AJOL)

    This paper therefore examines rural social organizations in bottom-up paradigm in sustainable rural transformation in Nigeria. In an attempt to justify the continued involvement of rural social organizations in rural transformation, the paper takes an overview on the short and long term strategies adopted so far by rural social ...

  17. Trophic control of mesopredators in terrestrial ecosystems: top-down or bottom-up?

    Science.gov (United States)

    Elmhagen, Bodil; Rushton, Stephen P

    2007-03-01

    It has been argued that widespread extinctions of top predators have changed terrestrial ecosystem structures through mesopredator release, where increased abundances of medium-sized predators have detrimental effects on prey communities. This top-down concept has received much attention within conservation biology, but few studies have demonstrated the phenomenon. The concept has been criticized since alternative explanations involving bottom-up impacts from bioclimatic effects on ecosystem productivity and from anthropogenic habitat change are rarely considered. We analyse the response of a mesopredator (the red fox) to declines in top predators (wolf and Eurasian lynx) and agricultural expansion over 90 years in Sweden, taking bioclimatic effects into account. We show a top-down mesopredator release effect, but ecosystem productivity determined its strength. The impacts of agricultural activity were mediated by their effects on top predator populations. Thus, both top-down and bottom-up processes need to be understood for effective preservation of biodiversity in anthropogenically transformed ecosystems.

  18. Combining bottom-up and top-down

    Energy Technology Data Exchange (ETDEWEB)

    Boehringer, Christoph [Department of Economics, University of Oldenburg, Oldenburg (Germany); Centre for European Economic Research (ZEW), Mannheim (Germany); Rutherford, Thomas F. [Ann Arbor, Michigan (United States)

    2008-03-15

    We motivate the formulation of market equilibrium as a mixed complementarity problem which explicitly represents weak inequalities and complementarity between decision variables and equilibrium conditions. The complementarity format permits an energy-economy model to combine technological detail of a bottom-up energy system with a second-best characterization of the over-all economy. Our primary objective is pedagogic. We first lay out the complementarity features of economic equilibrium and demonstrate how we can integrate bottom-up activity analysis into a top-down representation of the broader economy. We then provide a stylized numerical example of an integrated model - within both static and dynamic settings. Finally, we present illustrative applications to three themes figuring prominently on the energy policy agenda of many industrialized countries: nuclear phase-out, green quotas, and environmental tax reforms. (author)

  19. Peat accumulation in kettle holes: bottom up or top down?

    OpenAIRE

    G. Gaudig; Couwenberg, J; Joosten, H.

    2006-01-01

    Rapid peat formation in kettle hole-shaped basins may take place either a) by peat forming downwards (top down) from a floating mat under stable water level conditions (terrestrialisation), or b) by peat forming upwards (bottom up) as humus colloids seal off the basin, causing the water level to rise progressively (“kettle hole mire mechanism”). The latter mechanism has hardly been considered in the international literature. The floating-mat mechanism must lead to concave peat isochrones thro...

  20. Effects of salience are both short- and long-lived

    DEFF Research Database (Denmark)

    Orquin, Jacob Lund; Lagerkvist, Carl Johan

    2015-01-01

    necessarily override the latter. Instead, we find that the maximum effect of salience on the likelihood of making a saccade to the target cue is delayed until about 20 saccades after stimulus onset and that the effects of salience and valence are additive rather than multiplicative. Further, we find...... that in the positive and neutral valence conditions, salience continues to exert pressure on saccadic latency, i.e. the interval between saccades to the target with high salience targets being fixated faster than low salience targets. Our findings challenge the assumption that top down and bottom up processes operate...

  1. Bottom-up and top-down attention: different processes and overlapping neural systems.

    Science.gov (United States)

    Katsuki, Fumi; Constantinidis, Christos

    2014-10-01

    The brain is limited in its capacity to process all sensory stimuli present in the physical world at any point in time and relies instead on the cognitive process of attention to focus neural resources according to the contingencies of the moment. Attention can be categorized into two distinct functions: bottom-up attention, referring to attentional guidance purely by externally driven factors to stimuli that are salient because of their inherent properties relative to the background; and top-down attention, referring to internal guidance of attention based on prior knowledge, willful plans, and current goals. Over the past few years, insights on the neural circuits and mechanisms of bottom-up and top-down attention have been gained through neurophysiological experiments. Attention affects the mean neuronal firing rate as well as its variability and correlation across neurons. Although distinct processes mediate the guidance of attention based on bottom-up and top-down factors, a common neural apparatus, the frontoparietal network, is essential in both types of attentional processes. © The Author(s) 2013.

  2. Una implementación computacional de un modelo de atención visual Bottom-up aplicado a escenas naturales/A Computational Implementation of a Bottom-up Visual Attention Model Applied to Natural Scenes

    Directory of Open Access Journals (Sweden)

    Juan F. Ramírez Villegas

    2011-12-01

    Full Text Available El modelo de atención visual bottom-up propuesto por Itti et al., 2000 [1], ha sido un modelo popular en tanto exhibe cierta evidencia neurobiológica de la visión en primates. Este trabajo complementa el modelo computacional de este fenómeno desde la dinámica realista de una red neuronal. Asimismo, esta aproximación se basa en la existencia de mapas topográficos que representan la prominencia de los objetos del campo visual para la formación de una representación general (mapa de prominencia, esta representación es la entrada de una red neuronal dinámica con interacciones locales y globales de colaboración y competencia que convergen sobre las principales particularidades (objetos de la escena.The bottom-up visual attention model proposed by Itti et al. 2000 [1], has been a popular model since it exhibits certain neurobiological evidence of primates’ vision. This work complements the computational model of this phenomenon using a neural network with realistic dynamics. This approximation is based on several topographical maps representing the objects saliency that construct a general representation (saliency map, which is the input for a dynamic neural network, whose local and global collaborative and competitive interactions converge to the main particularities (objects presented by the visual scene as well.

  3. Top down, bottom up structured programming and program structuring

    Science.gov (United States)

    Hamilton, M.; Zeldin, S.

    1972-01-01

    New design and programming techniques for shuttle software. Based on previous Apollo experience, recommendations are made to apply top-down structured programming techniques to shuttle software. New software verification techniques for large software systems are recommended. HAL, the higher order language selected for the shuttle flight code, is discussed and found to be adequate for implementing these techniques. Recommendations are made to apply the workable combination of top-down, bottom-up methods in the management of shuttle software. Program structuring is discussed relevant to both programming and management techniques.

  4. Bottom-up silicon nanowire-based thermoelectric microgenerators

    Science.gov (United States)

    Dávila, D.; Huber, R.; Hierold, C.

    2015-12-01

    In this work, bottom-up intrinsic crystalline Si nanowire arrays in combination with top-down microfabrication techniques and a vertical device architecture have been proposed to develop an all-silicon nanostructured thermoelectric generator. To fabricate this device, a suitable vertical integration of Si NWs on patterned microstructures, which define the thermoelectric legs of the generator, has been achieved by bonding top and bottom silicon structures through nanowires. The process has been proven to be a feasible approach that employs a regrowth process of the nanowires for bonding purposes.

  5. Emotional face expression modulates occipital-frontal effective connectivity during memory formation in a bottom-up fashion.

    Science.gov (United States)

    Xiu, Daiming; Geiger, Maximilian J; Klaver, Peter

    2015-01-01

    This study investigated the role of bottom-up and top-down neural mechanisms in the processing of emotional face expression during memory formation. Functional brain imaging data was acquired during incidental learning of positive ("happy"), neutral and negative ("angry" or "fearful") faces. Dynamic Causal Modeling (DCM) was applied on the functional magnetic resonance imaging (fMRI) data to characterize effective connectivity within a brain network involving face perception (inferior occipital gyrus and fusiform gyrus) and successful memory formation related areas (hippocampus, superior parietal lobule, amygdala, and orbitofrontal cortex). The bottom-up models assumed processing of emotional face expression along feed forward pathways to the orbitofrontal cortex. The top-down models assumed that the orbitofrontal cortex processed emotional valence and mediated connections to the hippocampus. A subsequent recognition memory test showed an effect of negative emotion on the response bias, but not on memory performance. Our DCM findings showed that the bottom-up model family of effective connectivity best explained the data across all subjects and specified that emotion affected most bottom-up connections to the orbitofrontal cortex, especially from the occipital visual cortex and superior parietal lobule. Of those pathways to the orbitofrontal cortex the connection from the inferior occipital gyrus correlated with memory performance independently of valence. We suggest that bottom-up neural mechanisms support effects of emotional face expression and memory formation in a parallel and partially overlapping fashion.

  6. ICT-ENABLED BOTTOM-UP ARCHITECTURAL DESIGN

    Directory of Open Access Journals (Sweden)

    Burak Pak

    2016-04-01

    Full Text Available This paper aims at discussing the potentials of bottom-up design practices in relation to the latest developments in Information and Communication Technologies (ICT by making an in-depth review of inaugural cases. The first part of the study involves a literature study and the elaboration of basic strategies from the case study. The second part reframes the existing ICT tools and strategies and elaborates on their potentials to support the modes of participation performed in these cases. As a result, by distilling the created knowledge, the study reveals the potentials of novel modes of ICT-enabled design participation which exploit a set of collective action tools to support sustainable ways of self-organization and bottom-up design. The final part explains the relevance of these with solid examples and presents a hypothetical case for future implementation. The paper concludes with a brief reflection on the implications of the findings for the future of architectural design education.

  7. A bottom-up approach to MEDLINE indexing recommendations.

    Science.gov (United States)

    Jimeno-Yepes, Antonio; Wilkowski, Bartłomiej; Mork, James G; Van Lenten, Elizabeth; Fushman, Dina Demner; Aronson, Alan R

    2011-01-01

    MEDLINE indexing performed by the US National Library of Medicine staff describes the essence of a biomedical publication in about 14 Medical Subject Headings (MeSH). Since 2002, this task is assisted by the Medical Text Indexer (MTI) program. We present a bottom-up approach to MEDLINE indexing in which the abstract is searched for indicators for a specific MeSH recommendation in a two-step process. Supervised machine learning combined with triage rules improves sensitivity of recommendations while keeping the number of recommended terms relatively small. Improvement in recommendations observed in this work warrants further exploration of this approach to MTI recommendations on a larger set of MeSH headings.

  8. Making the results of bottom-up energy savings comparable

    Directory of Open Access Journals (Sweden)

    Moser Simon

    2012-01-01

    Full Text Available The Energy Service Directive (ESD has pushed forward the issue of energy savings calculations without clarifying the methodological basis. Savings achieved in the Member States are calculated with rather non-transparent and hardly comparable Bottom-up (BU methods. This paper develops the idea of parallel evaluation tracks separating the Member States’ issue of ESD verification and comparable savings calculations. Comparability is ensured by developing a standardised BU calculation kernel for different energy efficiency improvement (EEI actions which simultaneously depicts the different calculation options in a structured way (e.g. baseline definition, system boundaries, double counting. Due to the heterogeneity of BU calculations the approach requires a central database where Member States feed in input data on BU actions according to a predefined structure. The paper demonstrates the proposed approach including a concrete example of application.

  9. Planning from the bottom up. San Diego Regional Comprehensive Plan

    Directory of Open Access Journals (Sweden)

    Inés Sánchez de Madariaga

    2013-02-01

    Full Text Available Las ciudades contemporáneas se extienden cada vez más lejos en el territorio, de hecho, son ciudades que tienen espacios diferenciados, especializados y separados, para la vivienda y para la actividad económica, para el ocio y para el comercio, que se conectan entre sí a través de redes de transporte rodado. Este artículo pretende contribuir al conocimiento de estas experiencias recientes de control de la dispersión a través del caso de la Región de San Diego. El caso de San Diego reviste especial interés porque se trata de una experiencia de planificación bottom-up, es decir, de abajo arriba, y, como tal, sirve para ilustrar los mínimos posibles.

  10. Thinking about the Weather: How Display Salience and Knowledge Affect Performance in a Graphic Inference Task

    Science.gov (United States)

    Hegarty, Mary; Canham, Matt S.; Fabrikant, Sara I.

    2010-01-01

    Three experiments examined how bottom-up and top-down processes interact when people view and make inferences from complex visual displays (weather maps). Bottom-up effects of display design were investigated by manipulating the relative visual salience of task-relevant and task-irrelevant information across different maps. Top-down effects of…

  11. Semiconductor nanowires and nanowire heterostructures: Nanoscience from the bottom up

    Science.gov (United States)

    Zhong, Zhaohui

    2005-07-01

    Nanoscale science and technology involves interdisciplinary research at the interface of chemistry, physics, biology, and engineering sciences. By developing and following a unique intellectual path---the bottom-up paradigm of nanoscale science and technology---it is possible to assemble integrated nanoscale systems with novel functionalities beyond the conventional lithography limit. In this thesis, I present research efforts focused on fundamental aspects of this bottom-up paradigm using semiconductor nanowires (NWs) and nanowire heterostructures as nanoscale building blocks. We first present studies conducted on one of the most important semiconductor materials, silicon nanowires (SiNWs). SiNWs are rationally synthesized via a metal cluster-catalyzed vapor-liquid-solid (VLS) growth mechanism. Room temperature electrical transport studies carried out on SiNW field effect transistors (FETs) show exceptional device performance; estimated hole mobilities in p-SiNWs are significantly higher than bulk silicon at similar doping levels. Furthermore, low temperature transport studies on molecular scale SiNWs reveal phase coherent single charge transport through discrete single particle quantum levels with length scales up to several hundred nanometers. Finally, we show that SiNWs can be assembled into functional nanoelectronic devices. We then discuss two types of nanowire heterostructures: modulation doped silicon nanowires, and branched and hyper-branched nanowire structures. All key properties of modulation doped nanowires can be controlled during the synthesis, including the number, size and periodicity of the differentially doped regions. Their potential applications are also discussed. Moreover, branched and hyper-branched nanowire structures are synthesized via a multi-step nanocluster-catalyzed VLS approach, with branch density controlled by the nanocluster catalyst concentration. Lastly, we describe the realization of complementary doping in gallium nitride

  12. Bottom-up discrete symmetries for Cabibbo mixing

    Energy Technology Data Exchange (ETDEWEB)

    De Medeiros Varzielas, Ivo [Southampton Univ. (United Kingdom). School of Physics and Astronomy; Rasmussen, Rasmus W. [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany); Talbert, Jim [Oxford Univ. (United Kingdom). Rudolf Peierls Centre for Theoretical Physics

    2016-05-15

    We perform a bottom-up search for discrete non-Abelian symmetries capable of quantizing the Cabibbo angle that parameterizes CKM mixing. Given a particular Abelian symmetry structure in the up and down sectors, we construct representations of the associated residual generators which explicitly depend on the degrees of freedom present in our effective mixing matrix. We then discretize those degrees of freedom and utilize the Groups, Algorithms, Programming (GAP) package to close the associated finite groups. This short study is performed in the context of recent results indicating that, without resorting to special model-dependent corrections, no small-order finite group can simultaneously predict all four parameters of the three-generation CKM matrix and that only groups of O(10{sup 2}) can predict the analogous parameters of the leptonic PMNS matrix, regardless of whether neutrinos are Dirac or Majorana particles. Therefore a natural model of flavour might instead incorporate small(er) finite groups whose predictions for fermionic mixing are corrected via other mechanisms.

  13. Bottom-up nanotechnology: the human nephron filter.

    Science.gov (United States)

    Nissenson, Allen R

    2009-01-01

    Over one million patients worldwide have end-stage renal disease and require dialysis or kidney transplantation. Despite the availability of these forms of renal replacement therapy for nearly four decades, mortality and morbidity are high and patients often have a poor quality of life. We have developed a human nephron filter (HNF) utilizing bottom-up nanotechnology that would eventually make feasible a continuously functioning, wearable or implantable artificial kidney. The device consists of two membranes operating in series within one device cartridge. The first membrane mimics the function of the glomerulus, using convective transport to generate a plasma ultra filtrate, which contains all solutes approaching the molecular weight of albumin. The second membrane mimics the function of the renal tubules, selectively reclaiming designated solutes to maintain body homeostasis. No dialysis solution is used in this device. The HNF has been computer modeled, and operating 12 hour per day, 7 days per week the HNF provides the equivalent of 30 ml/min glomerular filtration rate (compared to half that amount for conventional thrice-weekly hemodialysis). The HNF system, by eliminating dialysate and utilizing a novel membrane system created through applied nanotechnology, represents a breakthrough in renal replacement therapy based on the functioning of native kidneys. The enhanced solute removal and wearable design should substantially improve patient outcomes and quality of life.

  14. Bottom-Up Synthesis and Sensor Applications of Biomimetic Nanostructures

    Directory of Open Access Journals (Sweden)

    Li Wang

    2016-01-01

    Full Text Available The combination of nanotechnology, biology, and bioengineering greatly improved the developments of nanomaterials with unique functions and properties. Biomolecules as the nanoscale building blocks play very important roles for the final formation of functional nanostructures. Many kinds of novel nanostructures have been created by using the bioinspired self-assembly and subsequent binding with various nanoparticles. In this review, we summarized the studies on the fabrications and sensor applications of biomimetic nanostructures. The strategies for creating different bottom-up nanostructures by using biomolecules like DNA, protein, peptide, and virus, as well as microorganisms like bacteria and plant leaf are introduced. In addition, the potential applications of the synthesized biomimetic nanostructures for colorimetry, fluorescence, surface plasmon resonance, surface-enhanced Raman scattering, electrical resistance, electrochemistry, and quartz crystal microbalance sensors are presented. This review will promote the understanding of relationships between biomolecules/microorganisms and functional nanomaterials in one way, and in another way it will guide the design and synthesis of biomimetic nanomaterials with unique properties in the future.

  15. Bottom-up Visual Integration in the Medial Parietal Lobe.

    Science.gov (United States)

    Pflugshaupt, Tobias; Nösberger, Myriam; Gutbrod, Klemens; Weber, Konrad P; Linnebank, Michael; Brugger, Peter

    2016-03-01

    Largely based on findings from functional neuroimaging studies, the medial parietal lobe is known to contribute to internally directed cognitive processes such as visual imagery or episodic memory. Here, we present 2 patients with behavioral impairments that extend this view. Both had chronic unilateral lesions of nearly the entire medial parietal lobe, but in opposite hemispheres. Routine neuropsychological examination conducted >4 years after the onset of brain damage showed little deficits of minor severity. In contrast, both patients reported persistent unusual visual impairment. A comprehensive series of tachistoscopic experiments with lateralized stimulus presentation and comparison with healthy participants revealed partial visual hemiagnosia for stimuli presented to their contralesional hemifield, applying inferential single-case statistics to evaluate deficits and dissociations. Double dissociations were found in 4 experiments during which participants had to integrate more than one visual element, either through comparison or formation of a global gestalt. Against the background of recent neuroimaging findings, we conclude that of all medial parietal structures, the precuneus is the most likely candidate for a crucial involvement in such bottom-up visual integration. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  16. Bottom-Up Synthesis and Sensor Applications of Biomimetic Nanostructures

    Science.gov (United States)

    Wang, Li; Sun, Yujing; Li, Zhuang; Wu, Aiguo; Wei, Gang

    2016-01-01

    The combination of nanotechnology, biology, and bioengineering greatly improved the developments of nanomaterials with unique functions and properties. Biomolecules as the nanoscale building blocks play very important roles for the final formation of functional nanostructures. Many kinds of novel nanostructures have been created by using the bioinspired self-assembly and subsequent binding with various nanoparticles. In this review, we summarized the studies on the fabrications and sensor applications of biomimetic nanostructures. The strategies for creating different bottom-up nanostructures by using biomolecules like DNA, protein, peptide, and virus, as well as microorganisms like bacteria and plant leaf are introduced. In addition, the potential applications of the synthesized biomimetic nanostructures for colorimetry, fluorescence, surface plasmon resonance, surface-enhanced Raman scattering, electrical resistance, electrochemistry, and quartz crystal microbalance sensors are presented. This review will promote the understanding of relationships between biomolecules/microorganisms and functional nanomaterials in one way, and in another way it will guide the design and synthesis of biomimetic nanomaterials with unique properties in the future. PMID:28787853

  17. Peat accumulation in kettle holes: bottom up or top down?

    Directory of Open Access Journals (Sweden)

    G. Gaudig

    2006-12-01

    Full Text Available Rapid peat formation in kettle hole-shaped basins may take place either a by peat forming downwards (top down from a floating mat under stable water level conditions (terrestrialisation, or b by peat forming upwards (bottom up as humus colloids seal off the basin, causing the water level to rise progressively (“kettle hole mire mechanism”. The latter mechanism has hardly been considered in the international literature. The floating-mat mechanism must lead to concave peat isochrones throughout the basin, whereas the kettle hole mire mechanism will yield surface-parallel isochrones. Peat isochrones were studied in three mires occupying kettle hole-shaped basins in north-eastern Germany by comparing pollen samples from the mineral soil–peat interface at different distances from the centre of each mire with the pollen assemblage profile of a central peat core. All three mires appeared to have largely surface-parallel isochrones and must have developed by the kettle hole mire mechanism. In one mire, this mechanism alternated and took place in combination with terrestrialisation following karst subsidence. The fact that evidence of the kettle hole mire mechanism was found at all of the sites investigated indicates that it may be a common peat forming mechanism in kettle hole-shaped basins worldwide.

  18. Bottom-up and top-down computations in word- and face-selective cortex

    Science.gov (United States)

    Kay, Kendrick N; Yeatman, Jason D

    2017-01-01

    The ability to read a page of text or recognize a person's face depends on category-selective visual regions in ventral temporal cortex (VTC). To understand how these regions mediate word and face recognition, it is necessary to characterize how stimuli are represented and how this representation is used in the execution of a cognitive task. Here, we show that the response of a category-selective region in VTC can be computed as the degree to which the low-level properties of the stimulus match a category template. Moreover, we show that during execution of a task, the bottom-up representation is scaled by the intraparietal sulcus (IPS), and that the level of IPS engagement reflects the cognitive demands of the task. These results provide an account of neural processing in VTC in the form of a model that addresses both bottom-up and top-down effects and quantitatively predicts VTC responses. DOI: http://dx.doi.org/10.7554/eLife.22341.001 PMID:28226243

  19. Proteomics in Heart Failure: Top-down or Bottom-up?

    Science.gov (United States)

    Gregorich, Zachery R.; Chang, Ying-Hua; Ge, Ying

    2014-01-01

    Summary The pathophysiology of heart failure (HF) is diverse, owing to multiple etiologies and aberrations in a number of cellular processes. Therefore, it is essential to understand how defects in the molecular pathways that mediate cellular responses to internal and external stressors function as a system to drive the HF phenotype. Mass spectrometry (MS)-based proteomics strategies have great potential for advancing our understanding of disease mechanisms at the systems level because proteins are the effector molecules for all cell functions and, thus, are directly responsible for determining cell phenotype. Two MS-based proteomics strategies exist: peptide-based bottom-up and protein-based top-down proteomics—each with its own unique strengths and weaknesses for interrogating the proteome. In this review, we will discuss the advantages and disadvantages of bottom-up and top-down MS for protein identification, quantification, and the analysis of post-translational modifications, as well as highlight how both of these strategies have contributed to our understanding of the molecular and cellular mechanisms underlying HF. Additionally, the challenges associated with both proteomics approaches will be discussed and insights will be offered regarding the future of MS-based proteomics in HF research. PMID:24619480

  20. On an elementary definition of visual saliency

    DEFF Research Database (Denmark)

    Loog, Marco

    2008-01-01

    Various approaches to computational modelling of bottom-up visual attention have been proposed in the past two decades. As part of this trend, researchers have studied ways to characterize the saliency map underlying many of these models. In more recent years, several definitions based...... on probabilistic and information or decision theoretic considerations have been proposed. These provide experimentally successful, appealing, low-level, operational, and elementary definitions of visual saliency (see eg, Bruce, 2005 Neurocomputing 65 125 - 133). Here, I demonstrate that, in fact, all...... these characterizations provide essentially the same measure of saliency. Moreover, where the original formulations rely on empirical estimates of the underlying probability density of low-level pre-attentive features, I show that saliency can be expressed as a closed-form solution based on purely local measurements and...

  1. Top down and bottom up engineering of bone.

    Science.gov (United States)

    Knothe Tate, Melissa L

    2011-01-11

    The goal of this retrospective article is to place the body of my lab's multiscale mechanobiology work in context of top-down and bottom-up engineering of bone. We have used biosystems engineering, computational modeling and novel experimental approaches to understand bone physiology, in health and disease, and across time (in utero, postnatal growth, maturity, aging and death, as well as evolution) and length scales (a single bone like a femur, m; a sample of bone tissue, mm-cm; a cell and its local environment, μm; down to the length scale of the cell's own skeleton, the cytoskeleton, nm). First we introduce the concept of flow in bone and the three calibers of porosity through which fluid flows. Then we describe, in the context of organ-tissue, tissue-cell and cell-molecule length scales, both multiscale computational models and experimental methods to predict flow in bone and to understand the flow of fluid as a means to deliver chemical and mechanical cues in bone. Addressing a number of studies in the context of multiple length and time scales, the importance of appropriate boundary conditions, site specific material parameters, permeability measures and even micro-nanoanatomically correct geometries are discussed in context of model predictions and their value for understanding multiscale mechanobiology of bone. Insights from these multiscale computational modeling and experimental methods are providing us with a means to predict, engineer and manufacture bone tissue in the laboratory and in the human body. Copyright © 2010 Elsevier Ltd. All rights reserved.

  2. Bottom-Up Syntheses and Characterization of One Dimensional Nanomaterials

    Science.gov (United States)

    Yeh, Yao-Wen

    Nanomaterials, materials having at least one dimension below 100 nm, have been creating exciting opportunities for fundamental quantum confinement studies and applications in electronic devices and energy technologies. One obvious and important aspect of nanomaterials is their production. Although nanostructures can be obtained by top-down reductive e-beam lithography and focused ion beam processes, further development of these processes is needed before these techniques can become practical routes to large scale production. On the other hand, bottom-up syntheses, with advantages in material diversity, throughput, and the potential for large volume production, may provide an alternative strategy for creating nanostructures. In this work, we explore syntheses of one dimensional nanostructures based on hydrothermal and arc discharge methods. The first project presented in this thesis involves syntheses of technologically important nanomaterials and their potential application in energy harvesting. In particular, it was demonstrated that single crystal ferroelectric lead magnesium niobate lead titanate (PMN-PT) nanowires can be synthesized by a hydrothermal route. The chemical composition of the synthesized nanowires is near the rhombohedral-monoclinic boundary of PMN-PT, which leads to a high piezoelectric coefficient of 381 pm/V. Finally, the potential use of PMN-PT nanowires in energy harvesting applications was also demonstrated. The second part of this thesis involves the synthesis of carbon and boron nitride nanotubes by dc arc discharges. In particular, we investigated how local plasma related properties affected the synthesis of carbon nanostructures. Finally, we investigated the anodic nature of the arc and how a dc arc discharge can be applied to synthesize boron nitride nanotubes.

  3. Saliency of color image derivatives: a comparison between computational models and human perception

    NARCIS (Netherlands)

    Vazquez, E.; Gevers, T.; Lucassen, M.; van de Weijer, J.; Baldrich, R.

    2010-01-01

    In this paper, computational methods are proposed to compute color edge saliency based on the information content of color edges. The computational methods are evaluated on bottom-up saliency in a psychophysical experiment, and on a more complex task of salient object detection in real-world images.

  4. Nanowire nanoelectronics assembled from the bottom-up

    Science.gov (United States)

    Duan, Xiangfeng

    2002-01-01

    In this thesis, a new paradigm for "bottom-up" assembly of nanoelectronics using nanowires (NWs) as building blocks has been defined. Three critical problems at the heart of device fabrication and integration will be addressed. First, we describe a general catalytic growth approach for the synthesis of a broad range of single crystal NWs of group III--V, II--VI and IV--IV binary and ternary alloy semiconductors with precisely controlled chemical composition, physical dimension, electronic and optical properties. In this approach, nanoclusters serve as catalytic sites confining and directing the growth of crystalline NWs through a vapor-liquid-solid growth mechanism. A key feature of this method is that the catalyst material and synthetic conditions can be rationally determined from phase diagram data and/or knowledge of chemical reactivity, and thus enables rational design and predictable syntheses. Moreover, catalytic nanocluster size and growth time can be used to precisely define the diameter and length of the NWs, and dopants can be flexibly introduced into the reactant to control the electronic properties. Second, we have performed a series of studies to characterize the physical properties of this new class of NW materials and utilized them for novel device fabrication. Photoluminescence studies show individual NWs exhibit strong quantum confined emission. Electrical transport studies demonstrate that these NWs can be doped as either n- or p-type material with carrier mobility comparable or larger than the bulk materials. The unique optical and electronic properties suggest that the NWs are of high quality and readily enable us to construct a variety of conceptually or fundamentally new types of nanoscale devices, including single NW field-effect transistors (FETs), crossed NW p-n junctions, crossed NW FETs, molecule-gated NW switching/memory devices, crossed NW light emitting diodes (LEDs), NW optical waveguide and optical cavity, highly polarization

  5. Coding of saliency by ensemble bursting in the amygdala of primates

    Directory of Open Access Journals (Sweden)

    Sara L Gonzalez Andino

    2012-07-01

    Full Text Available Salient parts of a visual scene attract longer and earlier fixations of the eyes. Saliency is driven by bottom-up (image dependent factors and top-down factors such as behavioral relevance, goals, and expertise. It is currently assumed that a saliency map defining eye fixation priorities is stored in neural structures that remain to be determined. Lesion studies support a role for the amygdala in detecting saliency. Here we show that neurons in the amygdala of primates fire differentially when the eyes approach to or fixate behaviorally relevant parts of visual scenes. Ensemble bursting in the amygdala accurately predicts main fixations during the free-viewing of natural images. However, fixation prediction is significantly better for faces - where a bottom-up computational saliency model fails - compared to unfamiliar objects and landscapes. On this basis we propose the amygdala as a locus for a saliency map and ensemble bursting as a saliency coding mechanism.

  6. Bottom-up capacity building for data providers in RITMARE

    Science.gov (United States)

    Pepe, Monica; Basoni, Anna; Bastianini, Mauro; Fugazza, Cristiano; Menegon, Stefano; Oggioni, Alessandro; Pavesi, Fabio; Sarretta, Alessandro; Carrara, Paola

    2014-05-01

    RITMARE is a Flagship Project by the Italian Ministry of Research, coordinated by the National Research Council (CNR). It aims at the interdisciplinary integration of Italian marine research. Sub-project 7 shall create an interoperable infrastructure for the project, capable of interconnecting the whole community of researchers involved. It will allow coordinating and sharing of data, processes, and information produced by the other sub-projects [1]. Spatial Data Infrastructures (SDIs) allow for interoperable sharing among heterogeneous, distributed spatial content providers. The INSPIRE Directive [2] regulates the development of a pan-european SDI despite the great variety of national approaches in managing spatial data. However, six years after its adoption, its growth is still hampered by technological, cultural, and methodological gaps. In particular, in the research sector, actors may not be prone to comply with INSPIRE (or feel not compelled to) because they are too concentrated on domain-specific activities or hindered by technological issues. Indeed, the available technologies and tools for enabling standard-based discovery and access services are far from being user-friendly and requires time-consuming activities, such as metadata creation. Moreover, the INSPIRE implementation guidelines do not accommodate an essential component in environmental research, that is, in situ observations. In order to overcome most of the aforementioned issues and to enable researchers to actively give their contribution in the creation of the project infrastructure, a bottom-up approach has been adopted: a software suite has been developed, called Starter Kit, which is offered to research data production units, so that they can become autonomous, independent nodes of data provision. The Starter Kit enables the provision of geospatial resources, either geodata (e.g., maps and layers) or observations pulled from sensors, which are made accessible according to the OGC standards

  7. On the plausibility of the discriminant center-surround hypothesis for visual saliency.

    Science.gov (United States)

    Gao, Dashan; Mahadevan, Vijay; Vasconcelos, Nuno

    2008-06-13

    It has been suggested that saliency mechanisms play a role in perceptual organization. This work evaluates the plausibility of a recently proposed generic principle for visual saliency: that all saliency decisions are optimal in a decision-theoretic sense. The discriminant saliency hypothesis is combined with the classical assumption that bottom-up saliency is a center-surround process to derive a (decision-theoretic) optimal saliency architecture. Under this architecture, the saliency of each image location is equated to the discriminant power of a set of features with respect to the classification problem that opposes stimuli at center and surround. The optimal saliency detector is derived for various stimulus modalities, including intensity, color, orientation, and motion, and shown to make accurate quantitative predictions of various psychophysics of human saliency for both static and motion stimuli. These include some classical nonlinearities of orientation and motion saliency and a Weber law that governs various types of saliency asymmetries. The discriminant saliency detectors are also applied to various saliency problems of interest in computer vision, including the prediction of human eye fixations on natural scenes, motion-based saliency in the presence of ego-motion, and background subtraction in highly dynamic scenes. In all cases, the discriminant saliency detectors outperform previously proposed methods from both the saliency and the general computer vision literatures.

  8. Seasonal shift from bottom-up to top-down impact in phytophagous insect populations.

    Science.gov (United States)

    Gratton, Claudio; Denno, Robert F

    2003-03-01

    Although many studies now examine how multiple factors influence the dynamics of herbivore populations, few studies explicitly attempt to document where and when each is important and how they vary and interact. In fact, how temporal variation in top-down (natural enemies) and bottom-up (host plant resources) factors affect herbivore dynamics has been suggested as a particularly important yet poorly understood feature of terrestrial food webs. In this study we examined how temporal changes in predator density (wolf spiders, sheet-web builders, and mirid egg predators) and host-plant resources (plant quality and structural complexity) influence the population dynamics of the dominant phytophagous insects on Atlantic-coast salt marshes, namely Prokelisia planthoppers (Homoptera: Delphacidae). We designed a factorial experiment in meadows of Spartina alterniflora to mimic natural variation in vegetation quality and structure by establishing two levels of plant nutrition (leaf nitrogen content) by fertilization, and two levels of habitat complexity by adding leaf litter (thatch). We then assessed seasonal changes in the strength of bottom-up (plant quality) and top-down (predator) impacts on planthopper populations. Planthopper populations responded positively to increased plant quality treatments in late summer. Despite the greater number of planthopper adults colonizing fertilized Spartina plots compared to unfertilized controls, the offspring of these colonists were much less abundant at the end of the season in fertilized plots, particularly those with thatch. The initial colonization effect was later erased because arthropod predators selectively accumulated in fertilized plots where they inflicted significant mortality on all stages of planthoppers. Predators rapidly colonized fertilized plots and reached high densities well in advance of planthopper colonization, a response we attribute to their rapid aggregation in complex-structured habitats with readily

  9. Charge transport in bottom-up inorganic-organic and quantum-coherent nanostructures

    NARCIS (Netherlands)

    Makarenko, K.S.

    2015-01-01

    This thesis is based on results obtained from experiments designed for a consistent study of charge transport in bottom-up inorganic-organic and quantum-coherent nanostructures. New unconventional ways to build elements of electrical circuits (like dielectrophoresis, wedging transfer and bottom-up

  10. Spatial bottom-up controls on fire likelihood vary across western North America

    Science.gov (United States)

    Sean A. Parks; Marc-Andre Parisien; Carol Miller

    2012-01-01

    The unique nature of landscapes has challenged our ability to make generalizations about the effects of bottom-up controls on fire regimes. For four geographically distinct fire-prone landscapes in western North America, we used a consistent simulation approach to quantify the influence of three key bottom-up factors, ignitions, fuels, and topography, on spatial...

  11. Interactions of top-down and bottom-up mechanisms in human visual cortex.

    Science.gov (United States)

    McMains, Stephanie; Kastner, Sabine

    2011-01-12

    Multiple stimuli present in the visual field at the same time compete for neural representation by mutually suppressing their evoked activity throughout visual cortex, providing a neural correlate for the limited processing capacity of the visual system. Competitive interactions among stimuli can be counteracted by top-down, goal-directed mechanisms such as attention, and by bottom-up, stimulus-driven mechanisms. Because these two processes cooperate in everyday life to bias processing toward behaviorally relevant or particularly salient stimuli, it has proven difficult to study interactions between top-down and bottom-up mechanisms. Here, we used an experimental paradigm in which we first isolated the effects of a bottom-up influence on neural competition by parametrically varying the degree of perceptual grouping in displays that were not attended. Second, we probed the effects of directed attention on the competitive interactions induced with the parametric design. We found that the amount of attentional modulation varied linearly with the degree of competition left unresolved by bottom-up processes, such that attentional modulation was greatest when neural competition was little influenced by bottom-up mechanisms and smallest when competition was strongly influenced by bottom-up mechanisms. These findings suggest that the strength of attentional modulation in the visual system is constrained by the degree to which competitive interactions have been resolved by bottom-up processes related to the segmentation of scenes into candidate objects.

  12. Learning affects top down and bottom up modulation of eye movements in decision making

    DEFF Research Database (Denmark)

    Orquin, Jacob Lund; Bagger, Martin; Mueller Loose, Simone

    2013-01-01

    it in a broader framework of top down and bottom up processes and derive the predictions that repeated decisions increase top down control of attention capture which in turn leads to a reduction in bottom up attention capture. To test our hypotheses we conducted a repeated discrete choice experiment with three...... different information presentation formats. We thereby operationalized top down and bottom up control as the effect of individual utility levels and presentation formats on attention capture on a trial-by-trial basis. The experiment revealed an increase in top down control of eye movements over time...

  13. A Bottom up Initiative: Meditation & Mindfulness 'Eastern' Practices in the "Western" Academia

    DEFF Research Database (Denmark)

    Singla, Rashmi

    a case of bottom up initiative, where the students themselves have demanded inclusion of non- conventional psychosocial interventions illustrated by meditation and mindfulness as Eastern psychological practices, thus filling the gap related to the existential, spiritual approaches. The western...

  14. Naval Force Sizing: Zero-Based or ’Bottoms-Up’ Method

    Science.gov (United States)

    1979-06-01

    25 III "BOTTOMS-UP" - WHAT IS IT? .......... . 25 Caveats ...... ................ 28 IV RISK ....... ................... . 29...acterized by a "count the bodies" philosophy. They argue that, 30 through quantitative methods to reduce measurement uncertainty, a strong clase can

  15. From exclusion to inclusion in public innovation support?: Innovative practices in bottom-up networks

    National Research Council Canada - National Science Library

    Lindberg, Malin

    2014-01-01

    ... – such as women, services industries and service innovations – could be acknowledged by the use of a bottom-up approach in innovation research in a way that helps make public innovation support more inclusive...

  16. Evaluation of Top-down and Bottom-up Leadership Development Programs in a Finnish Company

    OpenAIRE

    Kati Skarp; Keijo Varis; Juha Kettunen

    2017-01-01

    The purpose of this paper is to examine and evaluate the top-down and bottom-up leadership development programs focused on human capital that improve the performance of a company. This study reports on the external top-down leadership development program supported by a consulting company and the internal participatory action research of the bottom-up program. The sickness rate and the lost time incident failure rate decreased and the ideas produced for cost savings improved, leading to increa...

  17. What is Bottom-Up and What is Top-Down in Predictive Coding?

    Science.gov (United States)

    Rauss, Karsten; Pourtois, Gilles

    2013-01-01

    Everyone knows what bottom-up is, and how it is different from top-down. At least one is tempted to think so, given that both terms are ubiquitously used, but only rarely defined in the psychology and neuroscience literature. In this review, we highlight the problems and limitations of our current understanding of bottom-up and top-down processes, and we propose a reformulation of this distinction in terms of predictive coding. PMID:23730295

  18. Supporting Frequent Updates in R-Trees: A Bottom-Up Approach

    DEFF Research Database (Denmark)

    Lee, Mong Li; Hsu, Wynne; Jensen, Christian Søndergaard

    2004-01-01

    to improve update performance. It has different levels of reorganization - ranging from global to local - during updates, avoiding expensive top-down updates. A compact main-memory summary structure that allows direct access to the R-tree index nodes is used together with efficient bottom-up algorithms....... Empirical studies indicate that the bottom-up strategy outperforms the traditional top-down technique, leads to indices with better query performance, achieves higher throughput, and is scalable....

  19. Mapping practices of project management – merging top-down and bottom-up perspectives

    OpenAIRE

    Thuesen, Christian

    2015-01-01

    This paper presents a new methodology for studying different accounts of project management practices based on network mapping and analysis. Drawing upon network mapping and visualization as an analytical strategy top-down and bottom-up accounts of project management practice are analysed and compared. The analysis initially reveals a substantial difference between the top-down and bottom-up accounts of practice. Furthermore it identifies a soft side of project management that is central in t...

  20. Bottom-up synthetic biology: modular design for making artificial platelets

    Science.gov (United States)

    Majumder, Sagardip; Liu, Allen P.

    2018-01-01

    Engineering artificial cells to mimic one or multiple fundamental cell biological functions is an emerging area of synthetic biology. Reconstituting functional modules from biological components in vitro is a challenging yet an important essence of bottom-up synthetic biology. Here we describe the concept of building artificial platelets using bottom-up synthetic biology and the four functional modules that together could enable such an ambitious effort.

  1. Bottom-up vs. top-down effects on terrestrial insect herbivores: a meta-analysis.

    Science.gov (United States)

    Vidal, Mayra C; Murphy, Shannon M

    2018-01-01

    Primary consumers are under strong selection from resource ('bottom-up') and consumer ('top-down') controls, but the relative importance of these selective forces is unknown. We performed a meta-analysis to compare the strength of top-down and bottom-up forces on consumer fitness, considering multiple predictors that can modulate these effects: diet breadth, feeding guild, habitat/environment, type of bottom-up effects, type of top-down effects and how consumer fitness effects are measured. We focused our analyses on the most diverse group of primary consumers, herbivorous insects, and found that in general top-down forces were stronger than bottom-up forces. Notably, chewing, sucking and gall-making herbivores were more affected by top-down than bottom-up forces, top-down forces were stronger than bottom-up in both natural and controlled (cultivated) environments, and parasitoids and predators had equally strong top-down effects on insect herbivores. Future studies should broaden the scope of focal consumers, particularly in understudied terrestrial systems, guilds, taxonomic groups and top-down controls (e.g. pathogens), and test for more complex indirect community interactions. Our results demonstrate the surprising strength of forces exerted by natural enemies on herbivorous insects, and thus the necessity of using a tri-trophic approach when studying insect-plant interactions. © 2017 John Wiley & Sons Ltd/CNRS.

  2. Decision-theoretic saliency: computational principles, biological plausibility, and implications for neurophysiology and psychophysics.

    Science.gov (United States)

    Gao, Dashan; Vasconcelos, Nuno

    2009-01-01

    A decision-theoretic formulation of visual saliency, first proposed for top-down processing (object recognition) (Gao & Vasconcelos, 2005a), is extended to the problem of bottom-up saliency. Under this formulation, optimality is defined in the minimum probability of error sense, under a constraint of computational parsimony. The saliency of the visual features at a given location of the visual field is defined as the power of those features to discriminate between the stimulus at the location and a null hypothesis. For bottom-up saliency, this is the set of visual features that surround the location under consideration. Discrimination is defined in an information-theoretic sense and the optimal saliency detector derived for a class of stimuli that complies with known statistical properties of natural images. It is shown that under the assumption that saliency is driven by linear filtering, the optimal detector consists of what is usually referred to as the standard architecture of V1: a cascade of linear filtering, divisive normalization, rectification, and spatial pooling. The optimal detector is also shown to replicate the fundamental properties of the psychophysics of saliency: stimulus pop-out, saliency asymmetries for stimulus presence versus absence, disregard of feature conjunctions, and Weber's law. Finally, it is shown that the optimal saliency architecture can be applied to the solution of generic inference problems. In particular, for the class of stimuli studied, it performs the three fundamental operations of statistical inference: assessment of probabilities, implementation of Bayes decision rule, and feature selection.

  3. Bottom-up and top-down emotion generation: implications for emotion regulation.

    Science.gov (United States)

    McRae, Kateri; Misra, Supriya; Prasad, Aditya K; Pereira, Sean C; Gross, James J

    2012-03-01

    Emotion regulation plays a crucial role in adaptive functioning and mounting evidence suggests that some emotion regulation strategies are often more effective than others. However, little attention has been paid to the different ways emotions can be generated: from the 'bottom-up' (in response to inherently emotional perceptual properties of the stimulus) or 'top-down' (in response to cognitive evaluations). Based on a process priming principle, we hypothesized that mode of emotion generation would interact with subsequent emotion regulation. Specifically, we predicted that top-down emotions would be more successfully regulated by a top-down regulation strategy than bottom-up emotions. To test this hypothesis, we induced bottom-up and top-down emotions, and asked participants to decrease the negative impact of these emotions using cognitive reappraisal. We observed the predicted interaction between generation and regulation in two measures of emotional responding. As measured by self-reported affect, cognitive reappraisal was more successful on top-down generated emotions than bottom-up generated emotions. Neurally, reappraisal of bottom-up generated emotions resulted in a paradoxical increase of amygdala activity. This interaction between mode of emotion generation and subsequent regulation should be taken into account when comparing of the efficacy of different types of emotion regulation, as well as when reappraisal is used to treat different types of clinical disorders. © The Author (2011). Published by Oxford University Press.

  4. Combined contributions of feedforward and feedback inputs to bottom-up attention.

    Science.gov (United States)

    Khorsand, Peyman; Moore, Tirin; Soltani, Alireza

    2015-01-01

    In order to deal with a large amount of information carried by visual inputs entering the brain at any given point in time, the brain swiftly uses the same inputs to enhance processing in one part of visual field at the expense of the others. These processes, collectively called bottom-up attentional selection, are assumed to solely rely on feedforward processing of the external inputs, as it is implied by the nomenclature. Nevertheless, evidence from recent experimental and modeling studies points to the role of feedback in bottom-up attention. Here, we review behavioral and neural evidence that feedback inputs are important for the formation of signals that could guide attentional selection based on exogenous inputs. Moreover, we review results from a modeling study elucidating mechanisms underlying the emergence of these signals in successive layers of neural populations and how they depend on feedback from higher visual areas. We use these results to interpret and discuss more recent findings that can further unravel feedforward and feedback neural mechanisms underlying bottom-up attention. We argue that while it is descriptively useful to separate feedforward and feedback processes underlying bottom-up attention, these processes cannot be mechanistically separated into two successive stages as they occur at almost the same time and affect neural activity within the same brain areas using similar neural mechanisms. Therefore, understanding the interaction and integration of feedforward and feedback inputs is crucial for better understanding of bottom-up attention.

  5. New, national bottom-up estimate for tree-based biological ...

    Science.gov (United States)

    Nitrogen is a limiting nutrient in many ecosystems, but is also a chief pollutant from human activity. Quantifying human impacts on the nitrogen cycle and investigating natural ecosystem nitrogen cycling both require an understanding of the magnitude of nitrogen inputs from biological nitrogen fixation (BNF). A bottom-up approach to estimating BNF—scaling rates up from measurements to broader scales—is attractive because it is rooted in actual BNF measurements. However, bottom-up approaches have been hindered by scaling difficulties, and a recent top-down approach suggested that the previous bottom-up estimate was much too large. Here, we used a bottom-up approach for tree-based BNF, overcoming scaling difficulties with the systematic, immense (>70,000 N-fixing trees) Forest Inventory and Analysis (FIA) database. We employed two approaches to estimate species-specific BNF rates: published ecosystem-scale rates (kg N ha-1 yr-1) and published estimates of the percent of N derived from the atmosphere (%Ndfa) combined with FIA-derived growth rates. Species-specific rates can vary for a variety of reasons, so for each approach we examined how different assumptions influenced our results. Specifically, we allowed BNF rates to vary with stand age, N-fixer density, and canopy position (since N-fixation is known to require substantial light).Our estimates from this bottom-up technique are several orders of magnitude lower than previous estimates indicating

  6. Increased performance in a bottom-up designed robot by experimentally guided redesign

    DEFF Research Database (Denmark)

    Larsen, Jørgen Christian

    2013-01-01

    Purpose – Using a bottom-up, model-free approach when building robots is often seen as a less scientific way, compared to a top-down model-based approach, because the results are not easily generalizable to other systems. The authors, however, hypothesize that this problem may be addressed by using...... solid experimental methods. The purpose of this paper is to show how well-known experimental methods from bio-mechanics are used to measure and locate weaknesses in a bottom-up, model-free implementation of a quadruped walker and come up with a better solution. Design/methodology/approach – To study...... the bottom-up, mode-free approach, the authors used the robotic construction kit, LocoKit. This construction kit allows researchers to construct legged robots, without having a mathematical model beforehand. The authors used no specific mathematical model to design the robot, but instead used intuition...

  7. Top-down and bottom-up neurodynamic evidence in patients with tinnitus.

    Science.gov (United States)

    Hong, Sung Kwang; Park, Sejik; Ahn, Min-Hee; Min, Byoung-Kyong

    2016-12-01

    Although a peripheral auditory (bottom-up) deficit is an essential prerequisite for the generation of tinnitus, central cognitive (top-down) impairment has also been shown to be an inherent neuropathological mechanism. Using an auditory oddball paradigm (for top-down analyses) and a passive listening paradigm (for bottom-up analyses) while recording electroencephalograms (EEGs), we investigated whether top-down or bottom-up components were more critical in the neuropathology of tinnitus, independent of peripheral hearing loss. We observed significantly reduced P300 amplitudes (reflecting fundamental cognitive processes such as attention) and evoked theta power (reflecting top-down regulation in memory systems) for target stimuli at the tinnitus frequency of patients with tinnitus but without hearing loss. The contingent negative variation (reflecting top-down expectation of a subsequent event prior to stimulation) and N100 (reflecting auditory bottom-up selective attention) were different between the healthy and patient groups. Interestingly, when tinnitus patients were divided into two subgroups based on their P300 amplitudes, their P170 and N200 components, and annoyance and distress indices to their tinnitus sound were different. EEG theta-band power and its Granger causal neurodynamic results consistently support a double dissociation of these two groups in both top-down and bottom-up tasks. Directed cortical connectivity corroborates that the tinnitus network involves the anterior cingulate and the parahippocampal areas, where higher-order top-down control is generated. Together, our observations provide neurophysiological and neurodynamic evidence revealing a differential engagement of top-down impairment along with deficits in bottom-up processing in patients with tinnitus but without hearing loss. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

  8. Integrated Bottom-Up and Top-Down Proteomics of Patient-Derived Breast Tumor Xenografts.

    Science.gov (United States)

    Ntai, Ioanna; LeDuc, Richard D; Fellers, Ryan T; Erdmann-Gilmore, Petra; Davies, Sherri R; Rumsey, Jeanne; Early, Bryan P; Thomas, Paul M; Li, Shunqiang; Compton, Philip D; Ellis, Matthew J C; Ruggles, Kelly V; Fenyö, David; Boja, Emily S; Rodriguez, Henry; Townsend, R Reid; Kelleher, Neil L

    2016-01-01

    Bottom-up proteomics relies on the use of proteases and is the method of choice for identifying thousands of protein groups in complex samples. Top-down proteomics has been shown to be robust for direct analysis of small proteins and offers a solution to the "peptide-to-protein" inference problem inherent with bottom-up approaches. Here, we describe the first large-scale integration of genomic, bottom-up and top-down proteomic data for the comparative analysis of patient-derived mouse xenograft models of basal and luminal B human breast cancer, WHIM2 and WHIM16, respectively. Using these well-characterized xenograft models established by the National Cancer Institute's Clinical Proteomic Tumor Analysis Consortium, we compared and contrasted the performance of bottom-up and top-down proteomics to detect cancer-specific aberrations at the peptide and proteoform levels and to measure differential expression of proteins and proteoforms. Bottom-up proteomic analysis of the tumor xenografts detected almost 10 times as many coding nucleotide polymorphisms and peptides resulting from novel splice junctions than top-down. For proteins in the range of 0-30 kDa, where quantitation was performed using both approaches, bottom-up proteomics quantified 3,519 protein groups from 49,185 peptides, while top-down proteomics quantified 982 proteoforms mapping to 358 proteins. Examples of both concordant and discordant quantitation were found in a ∼60:40 ratio, providing a unique opportunity for top-down to fill in missing information. The two techniques showed complementary performance, with bottom-up yielding eight times more identifications of 0-30 kDa proteins in xenograft proteomes, but failing to detect differences in certain posttranslational modifications (PTMs), such as phosphorylation pattern changes of alpha-endosulfine. This work illustrates the potency of a combined bottom-up and top-down proteomics approach to deepen our knowledge of cancer biology, especially when

  9. Supporting Frequent Updates in R-Trees: A Bottom-Up Approach

    DEFF Research Database (Denmark)

    Lee, Mong Li; Hsu, Wynne; Jensen, Christian Søndergaard

    2003-01-01

    and aims to improve update performance. It has different levels of reorganization—ranging from global to local—during updates, avoiding expensive top-down updates. A compact main-memory summary structure that allows direct access to the R-tree index nodes is used together with efficient bottom......-up algorithms. Empirical studies show that the bottom-up strategy outperforms the traditional top-down technique, leads to indices with better query performance, achieves higher throughput, and is scalable....

  10. Fast and Bottom-Up Object Detection and Segmentation using Gestalt Principles

    OpenAIRE

    Kootstra G.; Kragic D.

    2011-01-01

    In many scenarios, domestic robot will regularly encounter unknown objects. In such cases, top-down knowledge about the object for detection, recognition, and classification cannot be used. To learn about the object, or to be able to grasp it, bottom-up object segmentation is an important competence for the robot. Also when there is top-down knowledge, prior segmentation of the object can improve recognition and classification. In this paper, we focus on the problem of bottom-up detection and...

  11. Integrated Assessment of Energy Policies: A Decomposition of Top-Down and Bottom-Up

    Energy Technology Data Exchange (ETDEWEB)

    Boehringer, Christoph (Univ. of Oldenburg (Germany)); Rutherford, Thomas F. (ETH Zuerich (Switzerland))

    2008-01-15

    The formulation of market equilibrium problems as mixed complementarity problems (MCP) permits integration of bottom-up programming models of the energy system into top-down general equilibrium models of the overall economy. Yet, in practise the MCP approach loses analytical tractability of income effects, when the energy system includes upper and lowrbounds on many decision variables . We therefore advocate the use of complementarity methods to solve only the top-down economic equilibrium model and employ quadratic programming to solve the underlying bottom-up energy supply model. A simple iterative procedure reconciles the equilibrium prices and quantities between both models.

  12. Mapping practices of project management – merging top-down and bottom-up perspectives

    DEFF Research Database (Denmark)

    Thuesen, Christian

    2015-01-01

    This paper presents a new methodology for studying different accounts of project management practices based on network mapping and analysis. Drawing upon network mapping and visualization as an analytical strategy top-down and bottom-up accounts of project management practice are analysed and com...

  13. Bottom-up processes influence the demography and life-cycle phenology of Hawaiian bird communities

    Science.gov (United States)

    Jared D. Wolfe; C. John Ralph; Andrew Wiegardt

    2017-01-01

    Changes in climate can indirectly regulate populations at higher trophic levels by influencing the availability of food resources in the lower reaches of the food web. As such, species that rely on fruit and nectar food resources may be particularly sensitive to these bottom-up perturbations due to the strength of their trophic linkages with climatically-...

  14. Achieving Campus Sustainability: Top-Down, Bottom-Up, or Neither?

    Science.gov (United States)

    Brinkhurst, Marena; Rose, Peter; Maurice, Gillian; Ackerman, Josef Daniel

    2011-01-01

    Purpose: The dynamics of organizational change related to environmental sustainability on university campuses are examined in this article. Whereas case studies of campus sustainability efforts tend to classify leadership as either "top-down" or "bottom-up", this classification neglects consideration of the leadership roles of…

  15. Multistable Perception: When Bottom-Up and Top-Down Coincide

    Science.gov (United States)

    Kornmeier, Jurgen; Hein, Christine Maira; Bach, Michael

    2009-01-01

    During prolonged observation of an ambiguous figure sudden perceptual reversals occur, while the stimulus itself stays unchanged. There is a vivid debate about whether bottom-up or top-down mechanisms underlie this phenomenon. In the present study, we investigated the interrelation of two experimental factors: volitional control and discontinuous…

  16. Lexical Quality and Reading Skill: Bottom-Up and Top-Down Contributions to Sentence Processing

    Science.gov (United States)

    Hersch, Jolyn; Andrews, Sally

    2012-01-01

    This research investigated whether spelling ability, an index of precise lexical representations, predicts the balance between bottom-up and top-down processing in online sentence processing among skilled readers, over and above contributions of reading ability, vocabulary, and working memory. The results showed that the combination of superior…

  17. Implementing collaborative improvement - top-down, bottom-up or both?

    DEFF Research Database (Denmark)

    Kaltoft, Rasmus; Boer, Harry; Caniato, Federico

    2007-01-01

    , the study identifies three different implementation approaches. The bottom-up learning-by-doing approach starts at a practical level, with simple improvement activities, and aims at gradually developing a wide range of CoI knowledge, skills and initiatives. The top-down directive approach starts...

  18. Bottom-up and top-down emotion generation: implications for emotion regulation

    Science.gov (United States)

    Misra, Supriya; Prasad, Aditya K.; Pereira, Sean C.; Gross, James J.

    2012-01-01

    Emotion regulation plays a crucial role in adaptive functioning and mounting evidence suggests that some emotion regulation strategies are often more effective than others. However, little attention has been paid to the different ways emotions can be generated: from the ‘bottom-up’ (in response to inherently emotional perceptual properties of the stimulus) or ‘top-down’ (in response to cognitive evaluations). Based on a process priming principle, we hypothesized that mode of emotion generation would interact with subsequent emotion regulation. Specifically, we predicted that top-down emotions would be more successfully regulated by a top-down regulation strategy than bottom-up emotions. To test this hypothesis, we induced bottom-up and top-down emotions, and asked participants to decrease the negative impact of these emotions using cognitive reappraisal. We observed the predicted interaction between generation and regulation in two measures of emotional responding. As measured by self-reported affect, cognitive reappraisal was more successful on top-down generated emotions than bottom-up generated emotions. Neurally, reappraisal of bottom-up generated emotions resulted in a paradoxical increase of amygdala activity. This interaction between mode of emotion generation and subsequent regulation should be taken into account when comparing of the efficacy of different types of emotion regulation, as well as when reappraisal is used to treat different types of clinical disorders. PMID:21296865

  19. An integrated top-down and bottom-up strategy for characterization protein isoforms and modifications

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Si; Tolic, Nikola; Tian, Zhixin; Robinson, Errol W.; Pasa-Tolic, Ljiljana

    2011-04-15

    Bottom-up and top-down strategies are two commonly used methods for mass spectrometry (MS) based protein identification; each method has its own advantages and disadvantages. In this chapter, we describe an integrated top-down and bottom-up approach facilitated by concurrent liquid chromatography-mass spectrometry (LC-MS) analysis and fraction collection for comprehensive high-throughput intact protein profiling. The approach employs a high resolution reversed phase (RP) LC separation coupled with LC eluent fraction collection and concurrent on-line MS with a high field (12 Tesla) Fourier-transform ion cyclotron resonance (FTICR) mass spectrometer. Protein elusion profiles and tentative modified protein identification are made using detected intact protein mass in conjunction with bottom-up protein identifications from the enzymatic digestion and analysis of corresponding LC fractions. Specific proteins of biological interest are incorporated into a target ion list for subsequent off-line gas-phase fragmentation that uses an aliquot of the original collected LC fraction, an aliquot of which was also used for bottom-up analysis.

  20. Comparing Top-Down with Bottom-Up Approaches: Teaching Data Modeling

    Science.gov (United States)

    Kung, Hsiang-Jui; Kung, LeeAnn; Gardiner, Adrian

    2013-01-01

    Conceptual database design is a difficult task for novice database designers, such as students, and is also therefore particularly challenging for database educators to teach. In the teaching of database design, two general approaches are frequently emphasized: top-down and bottom-up. In this paper, we present an empirical comparison of students'…

  1. Bottom-up and Top-down: An alternate classification of LD authoring approaches

    NARCIS (Netherlands)

    Sodhi, Tim; Miao, Yongwu; Brouns, Francis; Koper, Rob

    2007-01-01

    Sodhi, T., Miao, Y., Brouns, F., & Koper, E. J. R. (2007). Bottom-up and Top-down: An alternate classification of LD authoring approaches. Paper presented at the TENCompetence Open Workshop on Current research on IMS Learning Design and Lifelong Competence Development Infrastructures. June, 21-22,

  2. A constraint-based bottom-up counterpart to definite clause grammars

    DEFF Research Database (Denmark)

    Christiansen, Henning

    2004-01-01

    A new grammar formalism, CHR Grammars (CHRG), is proposed that provides a constraint-solving approach to language analysis, built on top of the programming language of Constraint Handling Rules in the same way as Definite Clause Grammars (DCG) on Prolog. CHRG works bottom-up and adds the following...

  3. Bottom-up and top-down tree transformations - a comparison

    NARCIS (Netherlands)

    Engelfriet, Joost

    1975-01-01

    The top-down and bottom-up tree transducer are incomparable with respect to their transformation power. The difference between them is mainly caused by the different order in which they use the facilities of copying and nondeterminism. One can however define certain simple tree transformations,

  4. Coupling 2D Finite Element Models and Circuit Equations Using a Bottom-Up Methodology

    Science.gov (United States)

    2002-11-01

    EQUATIONS USING A BOTTOM-UP METHODOLOGY E. G6mezl, J. Roger-Folch2 , A. Gabald6nt and A. Molina’ ’Dpto. de Ingenieria Eldctrica. Universidad Polit...de Ingenieria Elictrica. ETSII. Universidad Politdcnica de Valencia. PO Box 22012, 46071. Valencia, Spain. E-mail: iroger adie.upv.es ABSTRACT The

  5. Bottom-up control of water hyacinth weevil populations: Do the plants regulate the insects?

    Science.gov (United States)

    A key measure of dietary sufficiency relates to an insect’s reproductive ability so oögenesis, a nutrient-limited process, can be subject to bottom-up regulation. We hypothesized that aquatic nutrient flux seasonally affects ovarian development thereby controlling population growth of two specialis...

  6. Iodine versus Bromine Functionalization for Bottom-Up Graphene Nanoribbon Growth

    DEFF Research Database (Denmark)

    Bronner, Christopher; Marangoni, Tomas; Rizzo, Daniel J.

    2017-01-01

    Deterministic bottom-up approaches for synthesizing atomically well-defined graphene nanoribbons (GNRs) largely rely on the surface-catalyzed activation of selected labile bonds in a molecular precursor followed by step-growth polymerization and cyclodehydrogenation. While the majority of success...

  7. Teacher-Led Professional Development: A Proposal for a Bottom-up Structure Approach

    Science.gov (United States)

    Macias, Angela

    2017-01-01

    This article uses current research recommendations for teacher-led professional development as well as qualitative data from a set of grassroots conferences to propose a new model for bottom-up teacher-led professional development. This article argues that by providing a neutral space and recruiting expertise of local experts, a public sphere can…

  8. Who Should Be at the Top of Bottom-Up Development?

    OpenAIRE

    Rao, Vijayendra; Joshi, Shareen

    2017-01-01

    It is widely acknowledged that top-down support is essential for bottom-up participatory projects to be effectively implemented at scale. However, which level of government, national or sub-national, should be given the responsibility to implement such projects is an open question, with wide variations in practice. This paper analyzes qualitative and quantitative data from a natural experi...

  9. Ways toward a European Vocational Education and Training Space: A "Bottom-Up" Approach

    Science.gov (United States)

    Blings, Jessica; Spottl, Georg

    2008-01-01

    Purpose: This paper seeks to concentrate on bottom-up approaches in order to promote a European vocational education and training (VET) concept. The overall aim of this article is to demonstrate that sophisticated approaches still have a chance of becoming common practice in European countries. Design/methodology/approach: The centre of the…

  10. Co-financing of bottom-up approaches towards Broadband Infrastructure Development

    DEFF Research Database (Denmark)

    Williams, Idongesit

    2016-01-01

    networks –leading to the demise of some of these initiatives. This paper proposes co-financing of these networks as a means of sustaining the bottom-up Broadband network. The argument of this paper is anchored on two of developing country cases. One in India and the other in Ghana. One survived...

  11. Bottom-up GGM algorithm for constructing multiple layered hierarchical gene regulatory networks

    Science.gov (United States)

    Multilayered hierarchical gene regulatory networks (ML-hGRNs) are very important for understanding genetics regulation of biological pathways. However, there are currently no computational algorithms available for directly building ML-hGRNs that regulate biological pathways. A bottom-up graphic Gaus...

  12. Trophic cascades of bottom-up and top-down forcing on nutrients and plankton in the Kattegat, evaluated by modelling

    Science.gov (United States)

    Petersen, Marcell Elo; Maar, Marie; Larsen, Janus; Møller, Eva Friis; Hansen, Per Juel

    2017-05-01

    The aim of the study was to investigate the relative importance of bottom-up and top-down forcing on trophic cascades in the pelagic food-web and the implications for water quality indicators (summer phytoplankton biomass and winter nutrients) in relation to management. The 3D ecological model ERGOM was validated and applied in a local set-up of the Kattegat, Denmark, using the off-line Flexsem framework. The model scenarios were conducted by changing the forcing by ± 20% of nutrient inputs (bottom-up) and mesozooplankton mortality (top-down), and both types of forcing combined. The model results showed that cascading effects operated differently depending on the forcing type. In the single-forcing bottom-up scenarios, the cascade directions were in the same direction as the forcing. For scenarios involving top-down, there was a skipped-level-transmission in the trophic responses that was either attenuated or amplified at different trophic levels. On a seasonal scale, bottom-up forcing showed strongest response during winter-spring for DIN and Chl a concentrations, whereas top-down forcing had the highest cascade strength during summer for Chl a concentrations and microzooplankton biomass. On annual basis, the system was more bottom-up than top-down controlled. Microzooplankton was found to play an important role in the pelagic food web as mediator of nutrient and energy fluxes. This study demonstrated that the best scenario for improved water quality was a combined reduction in nutrient input and mesozooplankton mortality calling for the need of an integrated management of marine areas exploited by human activities.

  13. Comparison between bottom-up and top-down approaches in the estimation of measurement uncertainty.

    Science.gov (United States)

    Lee, Jun Hyung; Choi, Jee-Hye; Youn, Jae Saeng; Cha, Young Joo; Song, Woonheung; Park, Ae Ja

    2015-06-01

    Measurement uncertainty is a metrological concept to quantify the variability of measurement results. There are two approaches to estimate measurement uncertainty. In this study, we sought to provide practical and detailed examples of the two approaches and compare the bottom-up and top-down approaches to estimating measurement uncertainty. We estimated measurement uncertainty of the concentration of glucose according to CLSI EP29-A guideline. Two different approaches were used. First, we performed a bottom-up approach. We identified the sources of uncertainty and made an uncertainty budget and assessed the measurement functions. We determined the uncertainties of each element and combined them. Second, we performed a top-down approach using internal quality control (IQC) data for 6 months. Then, we estimated and corrected systematic bias using certified reference material of glucose (NIST SRM 965b). The expanded uncertainties at the low glucose concentration (5.57 mmol/L) by the bottom-up approach and top-down approaches were ±0.18 mmol/L and ±0.17 mmol/L, respectively (all k=2). Those at the high glucose concentration (12.77 mmol/L) by the bottom-up and top-down approaches were ±0.34 mmol/L and ±0.36 mmol/L, respectively (all k=2). We presented practical and detailed examples for estimating measurement uncertainty by the two approaches. The uncertainties by the bottom-up approach were quite similar to those by the top-down approach. Thus, we demonstrated that the two approaches were approximately equivalent and interchangeable and concluded that clinical laboratories could determine measurement uncertainty by the simpler top-down approach.

  14. Assessment of discrepancies between bottom-up and regional emission inventories in Norwegian urban areas

    Science.gov (United States)

    López-Aparicio, Susana; Guevara, Marc; Thunis, Philippe; Cuvelier, Kees; Tarrasón, Leonor

    2017-04-01

    This study shows the capabilities of a benchmarking system to identify inconsistencies in emission inventories, and to evaluate the reason behind discrepancies as a mean to improve both bottom-up and downscaled emission inventories. Fine scale bottom-up emission inventories for seven urban areas in Norway are compared with three regional emission inventories, EC4MACS, TNO_MACC-II and TNO_MACC-III, downscaled to the same areas. The comparison shows discrepancies in nitrogen oxides (NOx) and particulate matter (PM2.5 and PM10) when evaluating both total and sectorial emissions. The three regional emission inventories underestimate NOx and PM10 traffic emissions by approximately 20-80% and 50-90%, respectively. The main reasons for the underestimation of PM10 emissions from traffic in the regional inventories are related to non-exhaust emissions due to resuspension, which are included in the bottom-up emission inventories but are missing in the official national emissions, and therefore in the downscaled regional inventories. The benchmarking indicates that the most probable reason behind the underestimation of NOx traffic emissions by the regional inventories is the activity data. The fine scale NOx traffic emissions from bottom-up inventories are based on the actual traffic volume at the road link and are much higher than the NOx emissions downscaled from national estimates based on fuel sales and based on population for the urban areas. We have identified important discrepancies in PM2.5 emissions from wood burning for residential heating among all the inventories. These discrepancies are associated with the assumptions made for the allocation of emissions. In the EC4MACs inventory, such assumptions imply high underestimation of PM2.5 emissions from the residential combustion sector in urban areas, which ranges from 40 to 90% compared with the bottom-up inventories. The study shows that in three of the seven Norwegian cities there is need for further improvement of

  15. Agricultural ammonia emissions in China: reconciling bottom-up and top-down estimates

    Directory of Open Access Journals (Sweden)

    L. Zhang

    2018-01-01

    Full Text Available Current estimates of agricultural ammonia (NH3 emissions in China differ by more than a factor of 2, hindering our understanding of their environmental consequences. Here we apply both bottom-up statistical and top-down inversion methods to quantify NH3 emissions from agriculture in China for the year 2008. We first assimilate satellite observations of NH3 column concentration from the Tropospheric Emission Spectrometer (TES using the GEOS-Chem adjoint model to optimize Chinese anthropogenic NH3 emissions at the 1∕2°  ×  2∕3° horizontal resolution for March–October 2008. Optimized emissions show a strong summer peak, with emissions about 50 % higher in summer than spring and fall, which is underestimated in current bottom-up NH3 emission estimates. To reconcile the latter with the top-down results, we revisit the processes of agricultural NH3 emissions and develop an improved bottom-up inventory of Chinese NH3 emissions from fertilizer application and livestock waste at the 1∕2°  ×  2∕3° resolution. Our bottom-up emission inventory includes more detailed information on crop-specific fertilizer application practices and better accounts for meteorological modulation of NH3 emission factors in China. We find that annual anthropogenic NH3 emissions are 11.7 Tg for 2008, with 5.05 Tg from fertilizer application and 5.31 Tg from livestock waste. The two sources together account for 88 % of total anthropogenic NH3 emissions in China. Our bottom-up emission estimates also show a distinct seasonality peaking in summer, consistent with top-down results from the satellite-based inversion. Further evaluations using surface network measurements show that the model driven by our bottom-up emissions reproduces the observed spatial and seasonal variations of NH3 gas concentrations and ammonium (NH4+ wet deposition fluxes over China well, providing additional credibility to the improvements we have made to our

  16. Agricultural ammonia emissions in China: reconciling bottom-up and top-down estimates

    Science.gov (United States)

    Zhang, Lin; Chen, Youfan; Zhao, Yuanhong; Henze, Daven K.; Zhu, Liye; Song, Yu; Paulot, Fabien; Liu, Xuejun; Pan, Yuepeng; Lin, Yi; Huang, Binxiang

    2018-01-01

    Current estimates of agricultural ammonia (NH3) emissions in China differ by more than a factor of 2, hindering our understanding of their environmental consequences. Here we apply both bottom-up statistical and top-down inversion methods to quantify NH3 emissions from agriculture in China for the year 2008. We first assimilate satellite observations of NH3 column concentration from the Tropospheric Emission Spectrometer (TES) using the GEOS-Chem adjoint model to optimize Chinese anthropogenic NH3 emissions at the 1/2° × 2/3° horizontal resolution for March-October 2008. Optimized emissions show a strong summer peak, with emissions about 50 % higher in summer than spring and fall, which is underestimated in current bottom-up NH3 emission estimates. To reconcile the latter with the top-down results, we revisit the processes of agricultural NH3 emissions and develop an improved bottom-up inventory of Chinese NH3 emissions from fertilizer application and livestock waste at the 1/2° × 2/3° resolution. Our bottom-up emission inventory includes more detailed information on crop-specific fertilizer application practices and better accounts for meteorological modulation of NH3 emission factors in China. We find that annual anthropogenic NH3 emissions are 11.7 Tg for 2008, with 5.05 Tg from fertilizer application and 5.31 Tg from livestock waste. The two sources together account for 88 % of total anthropogenic NH3 emissions in China. Our bottom-up emission estimates also show a distinct seasonality peaking in summer, consistent with top-down results from the satellite-based inversion. Further evaluations using surface network measurements show that the model driven by our bottom-up emissions reproduces the observed spatial and seasonal variations of NH3 gas concentrations and ammonium (NH4+) wet deposition fluxes over China well, providing additional credibility to the improvements we have made to our agricultural NH3 emission inventory.

  17. Bottom-up and top-down effects on plant communities

    DEFF Research Database (Denmark)

    Souza, Lara; Zelikova, Tamara Jane; Sanders, Nate

    2016-01-01

    Top-down effects of herbivores and bottom-up effects of nutrients shape productivity and diversity across ecosystems, yet their single and combined effects on spatial and temporal beta diversity is unknown. We established a field experiment in which the abundance of insect herbivores (top-down...... affected ANPP while top-down factors influenced plant community structure. Across years, while N reduction lowered ANPP by 10%, N reduction did not alter ANPP relative to control plots. Further, N reduction lowered ANPP by 20% relative to N addition plots. On the other hand, the reduction of insect...... herbivores did not alter plant richness (α diversity) yet consistently promoted Shannon's evenness, relative to plots where insect herbivores were present. Further, insect herbivores promoted spatial-temporal β diversity. Overall, we found that the relative importance of top-down and bottom-up controls...

  18. Scaled CMOS Reliability and Considerations for Spacecraft Systems: Bottom-Up and Top-Down Perspective

    Science.gov (United States)

    White, Mark

    2012-01-01

    New space missions will increasingly rely on more advanced technologies because of system requirements for higher performance, particularly in instruments and high-speed processing. Component-level reliability challenges with scaled CMOS in spacecraft systems from a bottom-up perspective have been presented. Fundamental Front-end and Back-end processing reliability issues with more aggressively scaled parts have been discussed. Effective thermal management from system-level to the componentlevel (top-down) is a key element in overall design of reliable systems. Thermal management in space systems must consider a wide range of issues, including thermal loading of many different components, and frequent temperature cycling of some systems. Both perspectives (top-down and bottom-up) play a large role in robust, reliable spacecraft system design.

  19. Cognitive Functions of the Posterior Parietal Cortex: Top-down and bottom-up attentional control

    Directory of Open Access Journals (Sweden)

    Sarah eShomstein

    2012-07-01

    Full Text Available Although much less is known about human parietal cortex than that of homologous monkey cortex, recent studies, employing neuroimaging and neuropsychological methods, have begun to elucidate increasingly fine-grained functional and structural distinctions.This review is focused on recent neuroimaging and neuropsychological studies elucidating the cognitive roles of dorsal and ventral regions of parietal cortex in top-down and bottom-up attentional orienting, and on the interaction between the two attentional allocation mechanisms. Evidence is reviewed arguing that regions along the dorsal areas of the parietal cortex, including the superior parietal lobule (SPL are involved in top-down attentional orienting, while ventral regions including the temporo-parietal junction (TPJ are involved in bottom-up attentional orienting.

  20. Relative saliency model over multiple images with an application to yarn surface evaluation.

    Science.gov (United States)

    Liang, Zhen; Xu, Bingang; Chi, Zheru; Feng, David D

    2014-08-01

    Saliency models have been developed and widely demonstrated to benefit applications in computer vision and image understanding. In most of existing models, saliency is evaluated within an individual image. That is, saliency value of an item (object/region/pixel) represents the conspicuity of it as compared with the remaining items in the same image. We call this saliency as absolute saliency, which is uncomparable among images. However, saliency should be determined in the context of multiple images for some visual inspection tasks. For example, in yarn surface evaluation, saliency of a yarn image should be measured with regard to a set of graded standard images. We call this saliency the relative saliency, which is comparable among images. In this paper, a study of visual attention model for comparison of multiple images is explored, and a relative saliency model of multiple images is proposed based on a combination of bottom-up and top-down mechanisms, to enable relative saliency evaluation for the cases where other image contents are involved. To fully characterize the differences among multiple images, a structural feature extraction strategy is proposed, where two levels of feature (high-level, low-level) and three types of feature (global, local-local, local-global) are extracted. Mapping functions between features and saliency values are constructed and their outputs reflect relative saliency for multiimage contents instead of single image content. The performance of the proposed relative saliency model is well demonstrated in a yarn surface evaluation. Furthermore, the eye tracking technique is employed to verify the proposed concept of relative saliency for multiple images.

  1. Dissociable effects of top-down and bottom-up attention during episodic encoding

    Science.gov (United States)

    Uncapher, Melina R.; Hutchinson, J. Benjamin; Wagner, Anthony D.

    2011-01-01

    It is well established that the formation of memories for life’s experiences—episodic memory—is influenced by how we attend to those experiences, yet the neural mechanisms by which attention shapes episodic encoding are still unclear. We investigated how top-down and bottom-up attention contribute to memory encoding of visual objects in humans by manipulating both types of attention during functional magnetic resonance imaging (fMRI) of episodic memory formation. We show that dorsal parietal cortex—specifically, intraparietal sulcus (IPS)—was engaged during top-down attention and was also recruited during the successful formation of episodic memories. By contrast, bottom-up attention engaged ventral parietal cortex—specifically, temporoparietal junction (TPJ)—and was also more active during encoding failure. Functional connectivity analyses revealed further dissociations in how top-down and bottom-up attention influenced encoding: while both IPS and TPJ influenced activity in perceptual cortices thought to represent the information being encoded (fusiform/lateral occipital cortex), they each exerted opposite effects on memory encoding. Specifically, during a preparatory period preceding stimulus presentation, a stronger drive from IPS was associated with a higher likelihood that the subsequently attended stimulus would be encoded. By contrast, during stimulus processing, stronger connectivity with TPJ was associated with a lower likelihood the stimulus would be successfully encoded. These findings suggest that during encoding of visual objects into episodic memory, top-down and bottom-up attention can have opposite influences on perceptual areas that subserve visual object representation, suggesting that one manner in which attention modulates memory is by altering the perceptual processing of to-be-encoded stimuli. PMID:21880922

  2. A Positive Model of Earnings Forecasts: Top Down versus Bottom Up

    OpenAIRE

    Masako N. Darrough

    2002-01-01

    This article analyzes the behavior of two groups of corporate earnings forecasters: analysts, who follow individual company fortunes, and market strategists, who predict earnings for various company aggregates. Using data for two market indices, the S&P 500 and the Dow Jones Industrial Average, we document that bottom-up forecasts are systematically more optimistic than top-down forecasts made by strategists. This difference is not driven by the difference in the forecast target. This finding...

  3. A bottom-up approach for labeling of human airway trees

    DEFF Research Database (Denmark)

    2011-01-01

    In this paper, an airway labeling algorithm that allows for gaps between the labeled branches is introduced. A bottom-up approach for arriving to an optimal set of branches and their associated labels is used in the proposed method. A K nearest neighbor based appearance model is used to different...... with simulated errors, such as missing branches and having falsely detected branches, where we showed that such errors have little or no effect on the proposed method....

  4. Interactions between top-down and bottom-up attention in barn owls (Tyto alba).

    Science.gov (United States)

    Lev-Ari, Tidhar; Gutfreund, Yoram

    2017-12-06

    Selective attention, the prioritization of behaviorally relevant stimuli for behavioral control, is commonly divided into two processes: bottom-up, stimulus-driven selection and top-down, task-driven selection. Here, we tested two barn owls in a visual search task that examines attentional capture of the top-down task by bottom-up mechanisms. We trained barn owls to search for a vertical Gabor patch embedded in a circular array of differently oriented Gabor distractors (top-down guided search). To track the point of gaze, a lightweight wireless video camera was mounted on the owl's head. Three experiments were conducted in which the owls were tested in the following conditions: (1) five distractors; (2) nine distractors; (3) five distractors with one distractor surrounded by a red circle; or (4) five distractors with a brief sound at the initiation of the stimulus. Search times and number of head saccades to reach the target were measured and compared between the different conditions. It was found that search time and number of saccades to the target increased when the number of distractors was larger (condition 2) and when an additional irrelevant salient stimulus, auditory or visual, was added to the scene (conditions 3 and 4). These results demonstrate that in barn owls, bottom-up attention interacts with top-down attention to shape behavior in ways similar to human attentional capture. The findings suggest similar attentional principles in taxa that have been evolutionarily separated for 300 million years.

  5. A Bottom-up Trend in Research of Management of Technology

    Directory of Open Access Journals (Sweden)

    Yoko Ishino

    2014-12-01

    Full Text Available Management of Technology (MOT is defined as an academic discipline of management that enables organizations to manage their technological fundamentals to create competitive advantage. MOT covers a wide range of contents including administrative strategy, R&D management, manufacturing management, technology transfer, production control, marketing, accounting, finance, business ethics, and others. For each topic, researchers have conducted their MOT research at various levels. However, a practical and pragmatic side of MOT surely affects its research trends. Finding changes of MOT research trends, or the chronological transitions of principal subjects, can help understand the key concepts of current MOT. This paper studied a bottom-up trend in research fields in MOT by applying a text-mining method to the conference proceedings of IAMOT (International Association for Management of Technology. First, focusing on only nouns found several keywords, which more frequently emerge over time in the IAMOT proceedings. Then, expanding the scope into other parts of speech viewed the keywords in a natural context. Finally, it was found that the use of an important keyword has qualitatively and quantitatively extended over time. In conclusion, a bottom-up trend in MOT research was detected and the effects of the social situation on the trend were discussed.Keywords: Management of Technology; Text Mining; Research Trend; Bottom-up Trend; Patent

  6. Hierarchical time series bottom-up approach for forecast the export value in Central Java

    Science.gov (United States)

    Mahkya, D. A.; Ulama, B. S.; Suhartono

    2017-10-01

    The purpose of this study is Getting the best modeling and predicting the export value of Central Java using a Hierarchical Time Series. The export value is one variable injection in the economy of a country, meaning that if the export value of the country increases, the country’s economy will increase even more. Therefore, it is necessary appropriate modeling to predict the export value especially in Central Java. Export Value in Central Java are grouped into 21 commodities with each commodity has a different pattern. One approach that can be used time series is a hierarchical approach. Hierarchical Time Series is used Buttom-up. To Forecast the individual series at all levels using Autoregressive Integrated Moving Average (ARIMA), Radial Basis Function Neural Network (RBFNN), and Hybrid ARIMA-RBFNN. For the selection of the best models used Symmetric Mean Absolute Percentage Error (sMAPE). Results of the analysis showed that for the Export Value of Central Java, Bottom-up approach with Hybrid ARIMA-RBFNN modeling can be used for long-term predictions. As for the short and medium-term predictions, it can be used a bottom-up approach RBFNN modeling. Overall bottom-up approach with RBFNN modeling give the best result.

  7. Bottom-up effects of geologic parent material through ecological interaction webs

    Science.gov (United States)

    Bradley, R.

    2012-04-01

    Community ecologists study the interactions between species to understand what controls the distribution and abundance of different populations. Communities are thus portrayed as "interaction webs", in which different species exert reciprocal pressures on each other. In the case of one population being a resource for which another population is the consumer (i.e. food-web), reciprocal pressures are commonly referred to as "bottom-up" vs. "top-down" effects. The starting point for studying bottom-up effects is usually the vegetation (primary producers), and its end-point the decomposer community responsible for breaking down detrital matter from each trophic level. In my presentation, I will present results from three former graduate students, to argue that the starting point for studying bottom-up effects should be the geologic parent material (GPM), whose importance has often been overlooked by community ecologists. For example, our data show that GPM had a stronger effect on forest floor nutrient budgets than the identity or successional stage of the vegetation. Likewise, GPM had a strong effect on the structure of forest floor microbial communities, as well as their resistance to, and resilience from, disturbance. GPM also had a significant effect on the richness and diversity of understory plant communities from similar forest stands. Finally, we present evidence that soil fertility controls the resistance and tolerance of certain plant species to selective browsing, thereby affecting the composition of the dominant plant cover and the feeding patterns of large herbivores.

  8. Top-down and bottom-up modeling in system pharmacology to understand clinical efficacy: An example with NRTIs of HIV-1.

    Science.gov (United States)

    Duwal, Sulav; von Kleist, Max

    2016-10-30

    A major aim of Systems Pharmacology is to understand clinically relevant mechanisms of action (MOA) of drugs and to use this knowledge in order to optimize therapy. To enable this mission it is necessary to obtain knowledge on how in vitro testable insights translate into clinical efficacy. Mathematical modeling and data integration are essential components to achieve this goal. Two modeling philosophies are prevalent, each of which in isolation is not sufficient to achieve the above described: In a 'top-down' approach, a minimal pharmacokinetic-pharmacodynamic (PK-PD) model is derived from- and fitted to available clinical data. This model may lack interpretability in terms of mechanisms and may only be predictive for scenarios already covered by the data used to derive it. A 'bottom-up' approach builds on mechanistic insights derived from in vitro/ex vivo experiments, which can be conducted under controlled conditions, but may not be fully representative for the in vivo/clinical situation. In this work, we employ both approaches side-by-side to predict the clinical potency (IC50 values) of the nucleoside reverse transcriptase inhibitors (NRTIs) lamivudine, emtricitabine and tenofovir. In the 'top-down' approach, this requires to establish the dynamic link between the intracellularly active NRTI-triphosphates (which exert the effect) and plasma prodrug PK and to subsequently link this composite PK model to viral kinetics. The 'bottom-up' approach assesses inhibition of reverse transcriptase-mediated viral DNA polymerization by the intracellular, active NRTI-triphosphates, which has to be brought into the context of target cell infection. By using entirely disparate sets of data to derive and parameterize the respective models, our approach serves as a means to assess the clinical relevance of the 'bottom-up' approach. We obtain very good qualitative and quantitative agreement between 'top-down' vs. 'bottom-up' predicted IC50 values, arguing for the validity of the

  9. Bottom-Up or Top-Down: English as a Foreign Language Vocabulary Instruction for Chinese University Students

    Science.gov (United States)

    Moskovsky, Christo; Jiang, Guowu; Libert, Alan; Fagan, Seamus

    2015-01-01

    Whereas there has been some research on the role of bottom-up and top-down processing in the learning of a second or foreign language, very little attention has been given to bottom-up and top-down instructional approaches to language teaching. The research reported here used a quasi-experimental design to assess the relative effectiveness of two…

  10. A computational study of liposome logic: towards cellular computing from the bottom up.

    Science.gov (United States)

    Smaldon, James; Romero-Campero, Francisco J; Fernández Trillo, Francisco; Gheorghe, Marian; Alexander, Cameron; Krasnogor, Natalio

    2010-09-01

    In this paper we propose a new bottom-up approach to cellular computing, in which computational chemical processes are encapsulated within liposomes. This "liposome logic" approach (also called vesicle computing) makes use of supra-molecular chemistry constructs, e.g. protocells, chells, etc. as minimal cellular platforms to which logical functionality can be added. Modeling and simulations feature prominently in "top-down" synthetic biology, particularly in the specification, design and implementation of logic circuits through bacterial genome reengineering. The second contribution in this paper is the demonstration of a novel set of tools for the specification, modelling and analysis of "bottom-up" liposome logic. In particular, simulation and modelling techniques are used to analyse some example liposome logic designs, ranging from relatively simple NOT gates and NAND gates to SR-Latches, D Flip-Flops all the way to 3 bit ripple counters. The approach we propose consists of specifying, by means of P systems, gene regulatory network-like systems operating inside proto-membranes. This P systems specification can be automatically translated and executed through a multiscaled pipeline composed of dissipative particle dynamics (DPD) simulator and Gillespie's stochastic simulation algorithm (SSA). Finally, model selection and analysis can be performed through a model checking phase. This is the first paper we are aware of that brings to bear formal specifications, DPD, SSA and model checking to the problem of modeling target computational functionality in protocells. Potential chemical routes for the laboratory implementation of these simulations are also discussed thus for the first time suggesting a potentially realistic physiochemical implementation for membrane computing from the bottom-up.

  11. Visual anticipation biases conscious perception but not bottom-up visual processing

    Directory of Open Access Journals (Sweden)

    Paul F.M.J. Verschure

    2015-01-01

    Full Text Available Theories of consciousness can be grouped with respect to their stance on embodiment, sensori-motor contingencies, prediction and integration. In this list prediction plays a key role and it is not clear which aspects of prediction are most prominent in the conscious scene. An evolving view on the brain is that it can be seen as a prediction machine that optimizes its ability to predict states of the world and the self through the top-down propagation of predictions and the bottom-up presentation of prediction errors. There are competing views though on whether prediction or prediction errors dominate the conscious scene. Yet, due to the lack of efficient indirect measures, the dynamic effects of prediction on perception, decision making and consciousness have been difficult to assess and to model. We propose a novel mathematical framework and psychophysical paradigm that allows us to assess both the hierarchical structuring of perceptual consciousness, its content and the impact of predictions and / or errors on the conscious scene. Using a displacement detection task combined with reverse correlation we reveal signatures of the usage of prediction at three different levels of perception: bottom-up early saccades, top-down driven late saccades and conscious decisions. Our results suggest that the brain employs multiple parallel mechanisms at different levels of information processing to restrict the sensory field using predictions. We observe that cognitive load has a quantifiable effect on this dissociation of the bottom-up sensory and top-down predictive processes. We propose a probabilistic data association model from dynamical systems theory to model this predictive bias in different information processing levels.

  12. Enhanced Photon Extraction from a Nanowire Quantum Dot Using a Bottom-Up Photonic Shell

    DEFF Research Database (Denmark)

    Jeannin, Mathieu; Cremel, Thibault; Häyrynen, Teppo

    2017-01-01

    Semiconductor nanowires offer the possibility to grow high-quality quantum-dot heterostructures, and, in particular, CdSe quantum dots inserted in ZnSe nanowires have demonstrated the ability to emit single photons up to room temperature. In this paper, we demonstrate a bottom-up approach...... to fabricate a photonic fiberlike structure around such nanowire quantum dots by depositing an oxide shell using atomic-layer deposition. Simulations suggest that the intensity collected in our NA=0.6 microscope objective can be increased by a factor 7 with respect to the bare nanowire case. Combining...

  13. Scaled CMOS Reliability and Considerations for Spacecraft Systems : Bottom-Up and Top-Down Perspectives

    Science.gov (United States)

    White, Mark

    2012-01-01

    The recently launched Mars Science Laboratory (MSL) flagship mission, named Curiosity, is the most complex rover ever built by NASA and is scheduled to touch down on the red planet in August, 2012 in Gale Crater. The rover and its instruments will have to endure the harsh environments of the surface of Mars to fulfill its main science objectives. Such complex systems require reliable microelectronic components coupled with adequate component and system-level design margins. Reliability aspects of these elements of the spacecraft system are presented from bottom- up and top-down perspectives.

  14. Unsupervised tattoo segmentation combining bottom-up and top-down cues

    Science.gov (United States)

    Allen, Josef D.; Zhao, Nan; Yuan, Jiangbo; Liu, Xiuwen

    2011-06-01

    Tattoo segmentation is challenging due to the complexity and large variance in tattoo structures. We have developed a segmentation algorithm for finding tattoos in an image. Our basic idea is split-merge: split each tattoo image into clusters through a bottom-up process, learn to merge the clusters containing skin and then distinguish tattoo from the other skin via top-down prior in the image itself. Tattoo segmentation with unknown number of clusters is transferred to a figureground segmentation. We have applied our segmentation algorithm on a tattoo dataset and the results have shown that our tattoo segmentation system is efficient and suitable for further tattoo classification and retrieval purpose.

  15. Integrating Top-down and Bottom-up Cybersecurity Guidance using XML.

    Science.gov (United States)

    Lubell, Joshua

    2016-08-01

    This paper describes a markup-based approach for synthesizing disparate information sources and discusses a software implementation of the approach. The implementation makes it easier for people to use two complementary, but differently structured, guidance specifications together: the (top-down) Cybersecurity Framework and the (bottom-up) National Institute of Standards and Technology Special Publication 800-53 security control catalog. An example scenario demonstrates how the software implementation can help a security professional select the appropriate safeguards for restricting unauthorized access to an Industrial Control System. The implementation and example show the benefits of this approach and suggest its potential application to disciplines other than cybersecurity.

  16. Superconformal Bottom-Up Cobalt Deposition in High Aspect Ratio Through Silicon Vias.

    Science.gov (United States)

    Josell, D; Silva, M; Moffat, T P

    2016-01-01

    This work demonstrates void-free cobalt filling of 56 μm tall, annular Through Silicon Vias (TSVs) using a mechanism that couples suppression breakdown and surface topography to achieve controlled bottom-up deposition. The chemistry, a Watts electrolyte containing a dilute suppressing additive, and processes are described. This work extends understanding and application of the additive-derived S-shaped Negative Differential Resistance (S-NDR) mechanism, including previous demonstrations of superconformal filling of TSVs with nickel, copper, zinc and gold.

  17. Transformations Between Different Types of Unranked Bottom-Up Tree Automata

    Directory of Open Access Journals (Sweden)

    Xiaoxue Piao

    2010-08-01

    Full Text Available We consider the representational state complexity of unranked tree automata. The bottom-up computation of an unranked tree automaton may be either deterministic or nondeterministic, and further variants arise depending on whether the horizontal string languages defining the transitions are represented by a DFA or an NFA. Also, we consider for unranked tree automata the alternative syntactic definition of determinism introduced by Cristau et al. (FCT'05, Lect. Notes Comput. Sci. 3623, pp. 68-79. We establish upper and lower bounds for the state complexity of conversions between different types of unranked tree automata.

  18. Integrating Top-down and Bottom-up Cybersecurity Guidance using XML

    Science.gov (United States)

    Lubell, Joshua

    2016-01-01

    This paper describes a markup-based approach for synthesizing disparate information sources and discusses a software implementation of the approach. The implementation makes it easier for people to use two complementary, but differently structured, guidance specifications together: the (top-down) Cybersecurity Framework and the (bottom-up) National Institute of Standards and Technology Special Publication 800-53 security control catalog. An example scenario demonstrates how the software implementation can help a security professional select the appropriate safeguards for restricting unauthorized access to an Industrial Control System. The implementation and example show the benefits of this approach and suggest its potential application to disciplines other than cybersecurity. PMID:27795810

  19. Integrating the bottom-up and top-down approach to energy economy modelling. The case of Denmark

    DEFF Research Database (Denmark)

    Klinge Jacobsen, Henrik

    1998-01-01

    This paper presents results from an integration project covering Danish models based on bottom-up and top-down approaches to energy]economy modelling. The purpose of the project was to identify theoretical and methodological problems for integrating existing models for Denmark and to implement...... an integration of the models. The integration was established through a number of links between energy bottom-up modules and a macroeconomic model. In this integrated model it is possible to analyse both top-down instruments, such as taxes along with bottom-up instruments, such as regulation of technology...

  20. Attentional guidance by working memory overrides salience cues in visual search.

    Science.gov (United States)

    Dowd, Emma Wu; Mitroff, Stephen R

    2013-12-01

    Many factors influence visual search, including how much targets stand out (i.e., their visual salience) and whether they are currently relevant (i.e., Are they in working memory?). Although these are two known influences on search performance, it is unclear how they interact to guide attention. The present study explored this interplay by having participants hold an item in memory for a subsequent test while simultaneously conducting a multiple-target visual search. Importantly, the memory item could match one or neither of two targets from the search. In Experiment 1, when the memory item did not match either target, participants found a high-salience target first, demonstrating a baseline salience effect. This effect was exaggerated when a high-salience target was in working memory and completely reversed when a low-salience target was in memory, demonstrating a powerful influence of working memory guidance. Experiment 2 amplified the salience effect by including very high-salience, "pop-out"-like targets. Yet this salience effect was still attenuated when the memory item matched a less salient target. Experiment 3 confirmed these were memory-based effects and not priming. Collectively, these findings illustrate the influential role of working memory in guiding visual attention, even in the face of competing bottom-up salience cues.

  1. Integrating top-down/bottom-up sustainability strategies: an ethical challenge

    Directory of Open Access Journals (Sweden)

    John Cairns Jr.

    2003-02-01

    Full Text Available Sustainable use of the planet will require multiple sustainability strategies, which will range from the entire system, the entire Earth, the local or regional. Strategies starting at the highest system level are referred to as 'top-down', and strategies designed for components, local or regional, are referred to as 'bottom-up'. Doubtless, several intermediate levels will eventually be required, although the number is far from clear at this time. It is abundantly clear that both top-down and bottom-up strategies must be integrated effectively or neither will work well. Furthermore, there will be significant uncertainties at both levels of organisation, which will be reduced as evidence accumulates. However, sustainability is too complex and dynamic to reduce scientific uncertainty to a level desired by most decision makers. A great emphasis on sustain-ethics and value judgements will improve communications between those working at different organisational levels since humankind's wish to leave a habitable planet for its descendants and those of other life forms is clearly a value judgement.

  2. Top-down (Prior Knowledge) and Bottom-up (Perceptual Modality) Influences on Spontaneous Interpersonal Synchronization.

    Science.gov (United States)

    Gipson, Christina L; Gorman, Jamie C; Hessler, Eric E

    2016-04-01

    Coordination with others is such a fundamental part of human activity that it can happen unintentionally. This unintentional coordination can manifest as synchronization and is observed in physical and human systems alike. We investigated the role of top-down influences (prior knowledge of the perceptual modality their partner is using) and bottom-up factors (perceptual modality combination) on spontaneous interpersonal synchronization. We examine this phenomena with respect to two different theoretical perspectives that differently emphasize top-down and bottom-up factors in interpersonal synchronization: joint-action/shared cognition theories and ecological-interactive theories. In an empirical study twelve dyads performed a finger oscillation task while attending to each other's movements through either visual, auditory, or visual and auditory perceptual modalities. Half of the participants were given prior knowledge of their partner's perceptual capabilities for coordinating across these different perceptual modality combinations. We found that the effect of top-down influence depends on the perceptual modality combination between two individuals. When people used the same perceptual modalities, top-down influence resulted in less synchronization and when people used different perceptual modalities, top-down influence resulted in more synchronization. Furthermore, persistence in the change in behavior as a result of having perceptual information about each other ('social memory') was stronger when this top-down influence was present.

  3. A bottom-up approach for the synthesis of highly ordered fullerene-intercalated graphene hybrids

    Directory of Open Access Journals (Sweden)

    Dimitrios eGournis

    2015-02-01

    Full Text Available Much of the research effort on graphene focuses on its use as a building block for the development of new hybrid nanostructures with well-defined dimensions and properties suitable for applications such as gas storage, heterogeneous catalysis, gas/liquid separations, nanosensing and biomedicine. Towards this aim, here we describe a new bottom-up approach, which combines self-assembly with the Langmuir Schaefer deposition technique to synthesize graphene-based layered hybrid materials hosting fullerene molecules within the interlayer space. Our film preparation consists in a bottom-up layer-by-layer process that proceeds via the formation of a hybrid organo-graphene oxide Langmuir film. The structure and composition of these hybrid fullerene-containing thin multilayers deposited on hydrophobic substrates were characterized by a combination of X-ray diffraction, Raman and X-ray photoelectron spectroscopies, atomic force microscopy and conductivity measurements. The latter revealed that the presence of C60 within the interlayer spacing leads to an increase in electrical conductivity of the hybrid material as compared to the organo-graphene matrix alone.

  4. Painful faces-induced attentional blink modulated by top-down and bottom-up mechanisms

    Directory of Open Access Journals (Sweden)

    Chun eZheng

    2015-06-01

    Full Text Available Pain-related stimuli can capture attention in an automatic (bottom-up or intentional (top-down fashion. Previous studies have examined attentional capture by pain-related information using spatial attention paradigms that involve mainly a bottom-up mechanism. In the current study, we investigated the pain information–induced attentional blink (AB using a rapid serial visual presentation (RSVP task, and compared the effects of task-irrelevant and task-relevant pain distractors. Relationships between accuracy of target identification and individual traits (i.e., empathy and catastrophizing thinking about pain were also examined. The results demonstrated that task-relevant painful faces had a significant pain information–induced AB effect, whereas task-irrelevant faces a near-significant trend of this effect, supporting the notion that pain-related stimuli can influence the temporal dynamics of attention. Furthermore, we found a significant negative correlation between response accuracy and pain catastrophizing score in task-relevant trials. These findings suggest that active scanning of environmental information related to pain produces greater deficits in cognition than does unintentional attention toward pain, which may represent the different ways in which healthy individuals and patients with chronic pain process pain-relevant information. These results may provide insight into the understanding of maladaptive attentional processing in patients with chronic pain.

  5. Painful faces-induced attentional blink modulated by top-down and bottom-up mechanisms.

    Science.gov (United States)

    Zheng, Chun; Wang, Jin-Yan; Luo, Fei

    2015-01-01

    Pain-related stimuli can capture attention in an automatic (bottom-up) or intentional (top-down) fashion. Previous studies have examined attentional capture by pain-related information using spatial attention paradigms that involve mainly a bottom-up mechanism. In the current study, we investigated the pain information-induced attentional blink (AB) using a rapid serial visual presentation (RSVP) task, and compared the effects of task-irrelevant and task-relevant pain distractors. Relationships between accuracy of target identification and individual traits (i.e., empathy and catastrophizing thinking about pain) were also examined. The results demonstrated that task-relevant painful faces had a significant pain information-induced AB effect, whereas task-irrelevant faces showed a near-significant trend of this effect, supporting the notion that pain-related stimuli can influence the temporal dynamics of attention. Furthermore, we found a significant negative correlation between response accuracy and pain catastrophizing score in task-relevant trials. These findings suggest that active scanning of environmental information related to pain produces greater deficits in cognition than does unintentional attention toward pain, which may represent the different ways in which healthy individuals and patients with chronic pain process pain-relevant information. These results may provide insight into the understanding of maladaptive attentional processing in patients with chronic pain.

  6. Ecology of Caribbean sponges: are top-down or bottom-up processes more important?

    Science.gov (United States)

    Lesser, Michael P; Slattery, Marc

    2013-01-01

    Benthic-pelagic coupling and the role of bottom-up versus top-down processes are recognized as having a major impact on the structure of marine communities. While the roles of bottom-up processes are better appreciated they are still viewed as principally affecting the outcome of top-down processes. Sponges on coral reefs are important members of the benthic community and provide a critically important functional linkage between water-column productivity and the benthos. As active suspension feeders sponges utilize the abundant autotrophic and heterotrophic picoplankton in the water column. As a result sponges across the Caribbean basin exhibit a consistent and significant pattern of greater biomass, tube extension rate, and species numbers with increasing depth. Likewise, the abundance of their food supply also increases along a depth gradient. Using experimental manipulations it has recently been reported that predation is the primary determinant of sponge community structure. Here we provide data showing that the size and growth of the sponge Callyspongia vaginalis are significantly affected by food availability. Sponges increased in size and tube extension rate with increasing depth down to 46 m, while simultaneously exposed to the full range of potential spongivores at all depths. Additionally, we point out important flaws in the experimental design used to demonstrate the role of predation and suggest that a resolution of this important question will require well-controlled, multi-factorial experiments to examine the independent and interactive effects of predation and food abundance on the ecology of sponges.

  7. Bottom-Up Gazetteers: Learning from the Implicit Semantics of Geotags

    Science.gov (United States)

    Keßler, Carsten; Maué, Patrick; Heuer, Jan Torben; Bartoschek, Thomas

    As directories of named places, gazetteers link the names to geographic footprints and place types. Most existing gazetteers are managed strictly top-down: entries can only be added or changed by the responsible toponymic authority. The covered vocabulary is therefore often limited to an administrative view on places, using only official place names. In this paper, we propose a bottom-up approach for gazetteer building based on geotagged photos harvested from the web. We discuss the building blocks of a geotag and how they relate to each other to formally define the notion of a geotag. Based on this formalization, we introduce an extraction process for gazetteer entries that captures the emergent semantics of collections of geotagged photos and provides a group-cognitive perspective on named places. Using an experimental setup based on clustering and filtering algorithms, we demonstrate how to identify place names and assign adequate geographic footprints. The results for three different place names (Soho, Camino de Santiago and Kilimanjaro), representing different geographic feature types, are evaluated and compared to the results obtained from traditional gazetteers. Finally, we sketch how our approach can be combined with other (for example, linguistic) approaches and discuss how such a bottom-up gazetteer can complement existing gazetteers.

  8. Graphene devices with bottom-up contacts by area-selective atomic layer deposition

    Science.gov (United States)

    Thissen, Nick F. W.; Vervuurt, René H. J.; Mackus, Adriaan J. M.; Mulders, Johannes J. L.; Weber, Jan-Willem; Kessels, Wilhelmus M. M.; Bol, Ageeth A.

    2017-06-01

    Graphene field-effect transistor devices were fabricated using a bottom-up and resist-free method, avoiding common compatibility issues such as contamination by resist residues. Large-area CVD graphene sheets were structured into device channels by patterning with a focused ion beam. Platinum contacts were then deposited by direct-write atomic layer deposition (ALD), which is a combination between electron beam induced deposition (EBID) and bottom-up area-selective ALD. This is a unique approach that enables nucleation of Pt ALD on graphene, and therefore these devices are the first reported graphene devices with contacts deposited by ALD. Electrical characterization of the devices confirms ambipolar transistor behaviour with typical field-effect mobilities in the range of 1000-1800 cm2 V-1 s-1. We observe clear signs of strong Pt-graphene coupling and contact induced hole doping, implying good contact properties in contrast to the conventionally weak bonding between Pt and graphene. We attribute these observations to the reduced amount of resist residue under the contacts, the improved wettability of the Pt due to the use of ALD, and the formation of a graphitic interlayer that bonds the Pt more strongly to the graphene. We conclude that direct-write ALD is a very suitable technique for metallization of graphene devices and to study the intrinsic properties of metal-graphene contacts in more detail. In addition, it offers unique opportunities to control the metal-graphene coupling strength.

  9. Selective Ru ALD as a Catalyst for Sub-Seven-Nanometer Bottom-Up Metal Interconnects.

    Science.gov (United States)

    Zyulkov, Ivan; Krishtab, Mikhail; De Gendt, Stefan; Armini, Silvia

    2017-09-13

    Integrating bottom-up area-selective building-blocks in microelectronics has a disruptive potential because of the unique capability of engineering new structures and architectures. Atomic layer deposition (ALD) is an enabling technology, yet understanding the surfaces and their modification is crucial to leverage area-selective ALD (AS-ALD) in this field. The understanding of general selectivity mechanisms and the compatibility of plasma surface modifications with existing materials and processes, both at research and production scale, will greatly facilitate AS-ALD integration in microelectronics. The use of self-assembled monolayers to inhibit the nucleation and growth of ALD films is still scarcely compatible with nanofabrication because of defectivity and downscaling limitations. Alternatively, in this Research Article, we demonstrate a straightforward H 2 plasma surface modification process capable of inhibiting Ru ALD nucleation on an amorphous carbon surface while still allowing instantaneous nucleation and linear growth on Si-containing materials. Furthermore, we demonstrate how AS-ALD enables previously inaccessible routes, such as bottom-up electroless metal deposition in a dual damascene etch-damage free low-k replacement scheme. Specifically, our approach offers a general strategy for scalable ultrafine 3D nanostructures without the burden of subtractive metal patterning and high cost chemical mechanical planarization processes.

  10. Beam-deposited platinum as versatile catalyst for bottom-up silicon nanowire synthesis

    Science.gov (United States)

    Hibst, N.; Knittel, P.; Kranz, C.; Mizaikoff, B.; Strehle, S.

    2014-10-01

    The controlled localized bottom-up synthesis of silicon nanowires on arbitrarily shaped surfaces is still a persisting challenge for functional device assembly. In order to address this issue, electron beam and focused ion beam-assisted catalyst deposition have been investigated with respect to platinum expected to form a PtSi alloy catalyst for a subsequent bottom-up nanowire synthesis. The effective implementation of pure platinum nanoparticles or thin films for silicon nanowire growth has been demonstrated recently. Beam-deposited platinum contains significant quantities of amorphous carbon due to the organic precursor and gallium ions for a focused ion beam-based deposition process. Nevertheless, silicon nanowires could be grown on various substrates regardless of the platinum purity. Additionally, p-type doping could be realized with diborane whereas n-type doping suppressed a nanowire growth. The rational utilization of this beam-assisted approach enables us to control the localized synthesis of single silicon nanowires at planar surfaces but succeeded also in single nanowire growth at the three-dimensional apex of an atomic force microscopy tip. Therefore, this catalyst deposition method appears to be a unique extension of current technologies to assemble complex nanowire-based devices.

  11. Comparing effectiveness of top-down and bottom-up strategies in containing influenza.

    Directory of Open Access Journals (Sweden)

    Achla Marathe

    Full Text Available This research compares the performance of bottom-up, self-motivated behavioral interventions with top-down interventions targeted at controlling an "Influenza-like-illness". Both types of interventions use a variant of the ring strategy. In the first case, when the fraction of a person's direct contacts who are diagnosed exceeds a threshold, that person decides to seek prophylaxis, e.g. vaccine or antivirals; in the second case, we consider two intervention protocols, denoted Block and School: when a fraction of people who are diagnosed in a Census Block (resp., School exceeds the threshold, prophylax the entire Block (resp., School. Results show that the bottom-up strategy outperforms the top-down strategies under our parameter settings. Even in situations where the Block strategy reduces the overall attack rate well, it incurs a much higher cost. These findings lend credence to the notion that if people used antivirals effectively, making them available quickly on demand to private citizens could be a very effective way to control an outbreak.

  12. Superconformal Bottom-Up Gold Deposition in High Aspect Ratio Through Silicon Vias.

    Science.gov (United States)

    Josell, D; Moffat, T P

    2017-01-01

    This work presents superconformal, bottom-up Au filling of high aspect ratio through silicon vias (TSVs) along with a predictive framework based on the coupling of suppression breakdown and surface topography. The work extends a previous study of superconformal Au deposition in lower aspect ratio TSVs. Deposition was performed in a Na3AuSO3 electrolyte containing a branched polyethyleneimine (PEI) deposition-rate suppressing additive. Voltammetric measurements using a rotating disk electrode (RDE) were used to assess the impact of the PEI suppressor concentration and transport on the rate of metal deposition, enabling the interplay between metal deposition and suppressor adsorption to be quantified. The positive feedback associated with suppression breakdown gives rise to an S-shaped negative differential resistance (S-NDR). The derived kinetics for suppressor adsorption and consumption were used in a mass conservation model to account for bottom-up filling of patterned features. Predictions, including the impact of deposition potential and additive concentration on feature filling, are shown to match experimental results for filling of TSVs. This further generalizes the utility of the additive derived S-NDR model as a predictive formalism for identifying additives capable of generating localized, void-free filling of TSVs by electrodeposition.

  13. Top-down and bottom-up processes in speech comprehension.

    Science.gov (United States)

    Zekveld, Adriana A; Heslenfeld, Dirk J; Festen, Joost M; Schoonhoven, Ruurd

    2006-10-01

    Speech comprehension includes both bottom-up and top-down processes, and imaging studies have isolated a frontal-temporal network of brain areas active during speech perception. However, the precise role of the various areas in this network during normal speech comprehension is not yet fully understood. In the present fMRI study, the signal-to-noise ratio (SNR) of spoken sentences was varied in 144 steps, and speech intelligibility was measured independently in order to study in detail its effect on the activation of brain areas involved in speech perception. Relative to noise alone, intelligible speech in noise evoked spatially extended activation in left frontal, bilateral temporal, and medial occipital brain regions. Increasing SNR led to a sigmoid-shaped increase of activation in all areas of the frontal-temporal network. The onset of the activation with respect to SNR was similar in temporal and frontal regions, but frontal activation was found to be smaller than temporal activation at the highest SNRs. Finally, only Broca's area (BA44) showed activation to unintelligible speech presented at low SNRs. These findings demonstrate distinct roles of frontal and temporal areas in speech comprehension in that temporal regions subserve bottom-up processing of speech, whereas frontal areas are more involved in top-down supplementary mechanisms.

  14. A bottom-up model to describe consumers’ preferences towards late season peaches

    Energy Technology Data Exchange (ETDEWEB)

    Groot, E.; Albisu, L.M.

    2015-07-01

    Peaches are consumed in Mediterranean countries since ancient times. Nowadays there are few areas in Europe that produce peaches with Protected Designation of Origin (PDO), and the Calanda area is one of them. The aim of this work is to describe consumers’ preferences towards late season PDO Calanda peaches in the city of Zaragoza, Spain, by a bottom-up model. The bottom-up model proves greater amount of information than top-down models. In this approach it is estimated one utility function per consumer. Thus, it is not necessary to make assumptions about preference distributions and correlations across respondents. It was observed that preference distributions were neither normal nor independently distributed. If those preferences were estimated by top-down models, conclusions would be biased. This paper also explores a new way to describe preferences through individual utility functions. Results show that the largest behavioural group gathered origin sensitive consumers. Their utility increased if the peaches were produced in the Calanda area and, especially, when peaches had the PDO Calanda brand. In sequence, the second most valuable attribute for consumers was the price. Peach size and packaging were not so important on purchase choice decision. Nevertheless, it is advisable to avoid trading smallest size peaches (weighting around 160 g/fruit). Traders also have to be careful by using active packaging. It was found that a group of consumers disliked this kind of product, probably, because they perceived it as less natural. (Author)

  15. A bottom-up model to describe consumers’ preferences towards late season peaches

    Directory of Open Access Journals (Sweden)

    Etiénne Groot

    2015-12-01

    Full Text Available Peaches are consumed in Mediterranean countries since ancient times. Nowadays there are few areas in Europe that produce peaches with Protected Designation of Origin (PDO, and the Calanda area is one of them. The aim of this work is to describe consumers’ preferences towards late season PDO Calanda peaches in the city of Zaragoza, Spain, by a bottom-up model. The bottom-up model proves greater amount of information than top-down models. In this approach it is estimated one utility function per consumer. Thus, it is not necessary to make assumptions about preference distributions and correlations across respondents. It was observed that preference distributions were neither normal nor independently distributed. If those preferences were estimated by top-down models, conclusions would be biased. This paper also explores a new way to describe preferences through individual utility functions. Results show that the largest behavioural group gathered origin sensitive consumers. Their utility increased if the peaches were produced in the Calanda area and, especially, when peaches had the PDO Calanda brand. In sequence, the second most valuable attribute for consumers was the price. Peach size and packaging were not so important on purchase choice decision. Nevertheless, it is advisable to avoid trading smallest size peaches (weighting around 160 g/fruit. Traders also have to be careful by using active packaging. It was found that a group of consumers disliked this kind of product, probably, because they perceived it as less natural.

  16. Top-down and bottom-up definitions of human failure events in human reliability analysis

    Energy Technology Data Exchange (ETDEWEB)

    Boring, Ronald Laurids [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2014-10-01

    In the probabilistic risk assessments (PRAs) used in the nuclear industry, human failure events (HFEs) are determined as a subset of hardware failures, namely those hardware failures that could be triggered by human action or inaction. This approach is top-down, starting with hardware faults and deducing human contributions to those faults. Elsewhere, more traditionally human factors driven approaches would tend to look at opportunities for human errors first in a task analysis and then identify which of those errors is risk significant. The intersection of top-down and bottom-up approaches to defining HFEs has not been carefully studied. Ideally, both approaches should arrive at the same set of HFEs. This question is crucial, however, as human reliability analysis (HRA) methods are generalized to new domains like oil and gas. The HFEs used in nuclear PRAs tend to be top-down—defined as a subset of the PRA—whereas the HFEs used in petroleum quantitative risk assessments (QRAs) often tend to be bottom-up—derived from a task analysis conducted by human factors experts. The marriage of these approaches is necessary in order to ensure that HRA methods developed for top-down HFEs are also sufficient for bottom-up applications.

  17. Top-down and bottom-up forces interact at thermal range extremes on American lobster.

    Science.gov (United States)

    Boudreau, Stephanie A; Anderson, Sean C; Worm, Boris

    2015-05-01

    Exploited marine populations are thought to be regulated by the effects of fishing, species interactions and climate. Yet, it is unclear how these forces interact and vary across a species' range. We conducted a meta-analysis of American lobster (Homarus americanus) abundance data throughout the entirety of the species' range, testing competing hypotheses about bottom-up (climate, temperature) vs. top-down (predation, fishing) regulation along a strong thermal gradient. Our results suggest an interaction between predation and thermal range - predation effects dominated at the cold and warm extremes, but not at the centre of the species' range. Similarly, there was consistent support for a positive climate effect on lobster recruitment at warm range extremes. In contrast, fishing effort followed, rather than led changes in lobster abundance over time. Our analysis suggests that the relative effects of top-down and bottom-up forcing in regulating marine populations may intensify at thermal range boundaries and weaken at the core of a species' range. © 2014 The Authors. Journal of Animal Ecology © 2014 British Ecological Society.

  18. Feature combination strategies for saliency-based visual attention systems

    Science.gov (United States)

    Itti, Laurent; Koch, Christof

    2001-01-01

    Bottom-up or saliency-based visual attention allows primates to detect nonspecific conspicuous targets in cluttered scenes. A classical metaphor, derived from electrophysiological and psychophysical studies, describes attention as a rapidly shiftable `spot-light.' We use a model that reproduces the attentional scan paths of this spotlight. Simple multi-scale `feature maps' detect local spatial discontinuities in intensity, color, and orientation, and are combined into a unique `master' or `saliency' map. The saliency map is sequentially scanned, in order of decreasing saliency, by the focus of attention. We here study the problem of combining feature maps, from different visual modalities (such as color and orientation), into a unique saliency map. Four combination strategies are compared using three databases of natural color images: (1) Simple normalized summation, (2) linear combination with learned weights, (3) global nonlinear normalization followed by summation, and (4) local nonlinear competition between salient locations followed by summation. Performance was measured as the number of false detections before the most salient target was found. Strategy (1) always yielded poorest performance and (2) best performance, with a threefold to eightfold improvement in time to find a salient target. However, (2) yielded specialized systems with poor generalization. Interestingly, strategy (4) and its simplified, computationally efficient approximation (3) yielded significantly better performance than (1), with up to fourfold improvement, while preserving generality.

  19. Top-Down and Bottom-Up Cues Based Moving Object Detection for Varied Background Video Sequences

    Directory of Open Access Journals (Sweden)

    Chirag I. Patel

    2014-01-01

    there is no need for background formulation and updates as it is background independent. Many bottom-up approaches and one combination of bottom-up and top-down approaches are proposed in the present paper. The proposed approaches seem more efficient due to inessential requirement of learning background model and due to being independent of previous video frames. Results indicate that the proposed approach works even against slight movements in the background and in various outdoor conditions.

  20. Reconciliation of top-down and bottom-up CO2 fluxes in Siberian larch forest

    Science.gov (United States)

    Takata, Kumiko; Patra, Prabir K.; Kotani, Ayumi; Mori, Junko; Belikov, Dmitry; Ichii, Kazuhito; Saeki, Tazu; Ohta, Takeshi; Saito, Kazuyuki; Ueyama, Masahito; Ito, Akihiko; Maksyutov, Shamil; Miyazaki, Shin; Burke, Eleanor J.; Ganshin, Alexander; Iijima, Yoshihiro; Ise, Takeshi; Machiya, Hirokazu; Maximov, Trofim C.; Niwa, Yosuke; O’ishi, Ryo’ta; Park, Hotaek; Sasai, Takahiro; Sato, Hisashi; Tei, Shunsuke; Zhuravlev, Ruslan; Machida, Toshinobu; Sugimoto, Atsuko; Aoki, Shuji

    2017-12-01

    Carbon dioxide (CO2) fluxes by different methods vary largely at global, regional and local scales. The net CO2 fluxes by three bottom-up methods (tower observation (TWR), biogeochemical models (GTM), and a data-driven model (SVR)), and an ensemble of atmospheric inversions (top-down method, INV) are compared in Yakutsk, Siberia for 2004–2013. The region is characterized by highly homogeneous larch forest on a flat terrain. The ecosystem around Yakutsk shows a net sink of CO2 by all the methods (means during 2004–2007 were 10.9 g C m‑2 month‑1 by TWR, 4.28 g C m‑2 month‑1 by GTM, 5.62 g C m‑2 month‑1 and 0.863 g C m‑2 month‑1 by SVR at two different scales, and 4.89 g C m‑2 month‑1 by INV). Absorption in summer (June–August) was smaller by three bottom-up methods (ranged from 88.1 to 191.8 g C m‑2 month‑1) than the top-down method (223.6 g C m‑2 month‑1). Thus the peak-to-trough amplitude of the seasonal cycle is greater for the inverse models than bottom-up methods. The monthly-mean seasonal cycles agree among the four methods within the range of inter-model variations. The interannual variability estimated by an ensemble of inverse models and a site-scale data-driven model (the max-min range was 35.8 g C m‑2 month‑1and 34.2 g C m‑2 month‑1) is more similar to that of the tower observation (42.4 g C m‑2 month‑1) than those by the biogeochemical models and the large-scale data-driven model (9.5 g C m‑2 month‑1 and 1.45 g C m‑2 month‑1). The inverse models and tower observations captured a reduction in CO2 uptake after 2008 due to unusual waterlogging.

  1. Bottom-up communication. Identifying opportunities and limitations through an exploratory field-based evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Wilson, C.; Irvine, K.N. [Institute of Energy and Sustainable Development, De Montfort University, Leicester, LE1 9BH (United Kingdom)

    2013-02-15

    Communication to promote behaviours like energy saving can use significant resources. What is less clear is the comparative value of different approaches available to communicators. While it is generally agreed that 'bottom-up' approaches, where individuals are actively involved rather than passive, are preferable to 'top-down' authority-led projects, there is a dearth of evidence that verifies why this should be. Additionally, while the literature has examined the mechanics of the different approaches, there has been less attention paid to the associated psychological implications. This paper reports on an exploratory comparative study that examined the effects of six distinct communication activities. The activities used different communication approaches, some participative and others more top-down informational. Two theories, from behavioural studies and communication, were used to identify key variables for consideration in this field-based evaluation. The evaluation aimed to assess not just which activity might be most successful, as this has limited generalisability, but to also gain insight into what psychological impacts might contribute to success. Analysis found support for the general hypothesis that bottom-up approaches have more impact on behaviour change than top-down. The study also identified that, in this instance, the difference in reported behaviour across the activities related partly to the extent to which intentions to change behaviour were implemented. One possible explanation for the difference in reported behaviour change across the activities is that a bottom-up approach may offer a supportive environment where participants can discuss progress with like-minded individuals. A further possible explanation is that despite controlling for intention at an individual level, the pre-existence of strong intentions may have an effect on group success. These suggestive findings point toward the critical need for additional and larger-scale studies

  2. Altered top-down and bottom-up processing of fear conditioning in panic disorder with agoraphobia.

    Science.gov (United States)

    Lueken, U; Straube, B; Reinhardt, I; Maslowski, N I; Wittchen, H-U; Ströhle, A; Wittmann, A; Pfleiderer, B; Konrad, C; Ewert, A; Uhlmann, C; Arolt, V; Jansen, A; Kircher, T

    2014-01-01

    Although several neurophysiological models have been proposed for panic disorder with agoraphobia (PD/AG), there is limited evidence from functional magnetic resonance imaging (fMRI) studies on key neural networks in PD/AG. Fear conditioning has been proposed to represent a central pathway for the development and maintenance of this disorder; however, its neural substrates remain elusive. The present study aimed to investigate the neural correlates of fear conditioning in PD/AG patients. The blood oxygen level-dependent (BOLD) response was measured using fMRI during a fear conditioning task. Indicators of differential conditioning, simple conditioning and safety signal processing were investigated in 60 PD/AG patients and 60 matched healthy controls. Differential conditioning was associated with enhanced activation of the bilateral dorsal inferior frontal gyrus (IFG) whereas simple conditioning and safety signal processing were related to increased midbrain activation in PD/AG patients versus controls. Anxiety sensitivity was associated positively with the magnitude of midbrain activation. The results suggest changes in top-down and bottom-up processes during fear conditioning in PD/AG that can be interpreted within a neural framework of defensive reactions mediating threat through distal (forebrain) versus proximal (midbrain) brain structures. Evidence is accumulating that this network plays a key role in the aetiopathogenesis of panic disorder.

  3. Brain dynamics of distractibility: interaction between top-down and bottom-up mechanisms of auditory attention.

    Science.gov (United States)

    Bidet-Caulet, Aurélie; Bottemanne, Laure; Fonteneau, Clara; Giard, Marie-Hélène; Bertrand, Olivier

    2015-05-01

    Attention improves the processing of specific information while other stimuli are disregarded. A good balance between bottom-up (attentional capture by unexpected salient stimuli) and top-down (selection of relevant information) mechanisms is crucial to be both task-efficient and aware of our environment. Only few studies have explored how an isolated unexpected task-irrelevant stimulus outside the attention focus can disturb the top-down attention mechanisms necessary to the good performance of the ongoing task, and how these top-down mechanisms can modulate the bottom-up mechanisms of attentional capture triggered by an unexpected event. We recorded scalp electroencephalography in 18 young adults performing a new paradigm measuring distractibility and assessing both bottom-up and top-down attention mechanisms, at the same time. Increasing task load in top-down attention was found to reduce early processing of the distracting sound, but not bottom-up attentional capture mechanisms nor the behavioral distraction cost in reaction time. Moreover, the impact of bottom-up attentional capture by distracting sounds on target processing was revealed as a delayed latency of the N100 sensory response to target sounds mirroring increased reaction times. These results provide crucial information into how bottom-up and top-down mechanisms dynamically interact and compete in the human brain, i.e. on the precarious balance between voluntary attention and distraction.

  4. Compositional generative mapping for tree-structured data--part I: bottom-up probabilistic modeling of trees.

    Science.gov (United States)

    Bacciu, Davide; Micheli, Alessio; Sperduti, Alessandro

    2012-12-01

    We introduce a novel compositional (recursive) probabilistic model for trees that defines an approximated bottom-up generative process from the leaves to the root of a tree. The proposed model defines contextual state transitions from the joint configuration of the children to the parent nodes. We argue that the bottom-up context postulates different probabilistic assumptions with respect to a top-down approach, leading to different representational capabilities. We discuss classes of applications that are best suited to a bottom-up approach. In particular, the bottom-up context is shown to better correlate and model the co-occurrence of substructures among the child subtrees of internal nodes. A mixed memory approximation is introduced to factorize the joint children-to-parent state transition matrix as a mixture of pairwise transitions. The proposed approach is the first practical bottom-up generative model for tree-structured data that maintains the same computational class of its top-down counterpart. Comparative experimental analyses exploiting synthetic and real-world datasets show that the proposed model can deal with deep structures better than a top-down generative model. The model is also shown to better capture structural information from real-world data comprising trees with a large out-degree. The proposed bottom-up model can be used as a fundamental building block for the development of other new powerful models.

  5. Bottom-up coarse-graining of a simple graphene model: the blob picture.

    Science.gov (United States)

    Kauzlarić, David; Meier, Julia T; Español, Pep; Succi, Sauro; Greiner, Andreas; Korvink, Jan G

    2011-02-14

    The coarse-graining of a simple all-atom 2D microscopic model of graphene, in terms of "blobs" described by center of mass variables, is presented. The equations of motion of the coarse-grained variables take the form of dissipative particle dynamics (DPD). The coarse-grained conservative forces and the friction of the DPD model are obtained via a bottom-up procedure from molecular dynamics (MD) simulations. The separation of timescales for blobs of 24 and 96 carbon atoms is sufficiently pronounced for the Markovian assumption, inherent to the DPD model, to provide satisfactory results. In particular, the MD velocity autocorrelation function of the blobs is well reproduced by the DPD model, provided that the effect of friction and noise is taken into account. However, DPD cross-correlations between neighbor blobs show appreciable discrepancies with respect to the MD results. Possible extensions to mend these discrepancies are briefly outlined.

  6. Plasmonic nanoparticles for a bottom-up approach to fabricate optical metamaterials

    Science.gov (United States)

    Dintinger, José; Scharf, Toralf

    2012-03-01

    We investigate experimentally metallic nanoparticle composites fabricated by bottom-up techniques as potential candidates for optical metamaterials. Depending on the plasmonic resonances sustained by individual NPs and their nanoscale organization into larger meta-atoms, various properties might emerge. Here, the focus of our contribution is on the fabrication and optical characterization of silver NP clusters with a spherical shape. We start with the characterisation of the "bulk" dielectric constants of silver NP inks by spectroscopic ellipsometry for different nanoparticle densities (i.e from strongly diluted dispersions to solid randomly packed films). The inks are then used to prepare spherical nanoparticle clusters by an oil-in water emulsion technique. The study of their optical properties demonstrates their ability to support Mie resonances in the visible. These resonances are associated with the excitation of a magnetic dipole, which constitutes a prerequisite to the realization of metamaterials with negative permeability.

  7. Bottom-up control of geomagnetic secular variation by the Earth's inner core

    DEFF Research Database (Denmark)

    Aubert, Julien; Finlay, Chris; Fournier, Alexandre

    2013-01-01

    of geomagnetic secular variation. Here we show that it can be reproduced provided that two mechanisms relying on the inner core are jointly considered. First, gravitational coupling5 aligns the inner core with the mantle, forcing the flow of liquid metal in the outer core into a giant, westward drifting, sheet...... release in the outer core which in turn distorts the gyre, forcing it to become eccentric, in agreement with recent core flow inversions6, 10, 11. This bottom-up heterogeneous driving of core convection dominates top-down driving from mantle thermal heterogeneities, and localizes magnetic variations....... This is a consequence of the geographical localization of intense, westward drifting, equatorial magnetic flux patches at the core surface3. Despite successes in explaining the morphology of the geomagnetic field4, numerical models of the geodynamo have so far failed to account systematically for this striking pattern...

  8. Bottom-up effects of climate on fish populations: data from the Continuous Plankton Recorder

    DEFF Research Database (Denmark)

    Pitois, S.G.; Lynam, C.P.; Jansen, Teunis

    2012-01-01

    a unique opportunity to investigate long-term changes over decadal scales in the abundance and distribution of fish larvae in relation to physical and biological factors. A principal component analysis (PCA) using 7 biotic and abiotic parameters is applied to investigate the impact of environmental changes...... in the plankton ecosystem, while the larvae of migratory species such as Atlantic mackerel responded more to hydrographic changes. Climate variability seems more likely to influence fish populations through bottom-up control via a cascading effect from changes in the North Atlantic Oscillation (NAO) impacting...... on the hydro dynamic features of the North Sea, in turn impacting on the plankton available as prey for fish larvae. The responses and adaptability of fish larvae to changing environmental conditions, parti cularly to changes in prey availability, are complex and species-specific. This complexity is enhanced...

  9. Comparing top-down and bottom-up costing approaches for economic evaluation within social welfare.

    Science.gov (United States)

    Olsson, Tina M

    2011-10-01

    This study compares two approaches to the estimation of social welfare intervention costs: one "top-down" and the other "bottom-up" for a group of social welfare clients with severe problem behavior participating in a randomized trial. Intervention costs ranging over a two-year period were compared by intervention category (foster care placement, institutional placement, mentorship services, individual support services and structured support services), estimation method (price, micro costing, average cost) and treatment group (intervention, control). Analyses are based upon 2007 costs for 156 individuals receiving 404 interventions. Overall, both approaches were found to produce reliable estimates of intervention costs at the group level but not at the individual level. As choice of approach can greatly impact the estimate of mean difference, adjustment based on estimation approach should be incorporated into sensitivity analyses. Analysts must take care in assessing the purpose and perspective of the analysis when choosing a costing approach for use within economic evaluation.

  10. Top-Down Versus Bottom-Up Nanoengineering Routes to Design Advanced Oropharmacological Products.

    Science.gov (United States)

    Singh, Ajay V; Mehta, Krunal K

    2016-01-01

    Energy intensive and chemical routes predominately govern modern dental material fabrication involving complex physicochemical approaches. Current interest in dental material design is shifting towards biomineralization method and green chemistry synthesis to support oral tissue biocompatibility and oropharmacology. This review article describes the context of biophysical approaches based on development in nanoengineering to design advance nanomaterials for clinical dentistry. We particularly focus on approaches governing surface texture and hierarchical assembly emphasis based on micro-nanoscale tooth anatomy. Further, this article provides an overview about the merit of micro-nanoscale material design techniques exchanging the traditional dental material. In this context, top-down and bottom-up approaches involving biomimetic nanoengineering route, opportunities and challenges are discussed.

  11. Top-down and bottom-up guidance in comprehension of schematic football diagrams.

    Science.gov (United States)

    Khacharem, Aïmen

    2017-06-01

    Comprehension of a narrated diagram entail complex cognitive processing as learner is challenged to extract the orally evoked information. The present experiment examined the effects of 2 different forms of attention guidance - bottom-up and top-down - on comprehension performance, cognitive load investment, and motivation to learn, using a 2 × 2 mixed design with factors "Expertise" (Expert vs. Novice) and "Condition" (no-signal, circle, segment). The results revealed an expertise reversal effect indicating that the incorporation of visual signals in diagram is effective for novice learners but partially reverses and becomes ineffective for more experienced learners (even though they invested less mental effort and reported higher level of motivation in the segmented condition). The findings suggested that the effectiveness of instructional guidance depends heavily on levels of prior knowledge.

  12. Unsupervised Tattoo Segmentation Combining Bottom-Up and Top-Down Cues

    Energy Technology Data Exchange (ETDEWEB)

    Allen, Josef D [ORNL

    2011-01-01

    Tattoo segmentation is challenging due to the complexity and large variance in tattoo structures. We have developed a segmentation algorithm for nding tattoos in an image. Our basic idea is split-merge: split each tattoo image into clusters through a bottom-up process, learn to merge the clusters containing skin and then distinguish tattoo from the other skin via top-down prior in the image itself. Tattoo segmentation with unknown number of clusters is transferred to a gure-ground segmentation. We have applied our segmentation algorithm on a tattoo dataset and the results have shown that our tattoo segmentation system is e cient and suitable for further tattoo classi cation and retrieval purpose.

  13. A bottom-up perspective on leadership of collaborative innovation in the public sector

    DEFF Research Database (Denmark)

    Hansen, Jesper Rohr

    . A crucial condition for success is iterative leadership adaptation. In conclusion, the thesis finds that specialized professionals are indeed able to develop politically viable, innovative and collaborative solutions to wicked problems; and that such professionals are able to transform themselves......The thesis investigates how new forms of public leadership can contribute to solving complex problems in today’s welfare societies through innovation. A bottom-up type of leadership for collaborative innovation addressing wicked problems is theorised, displaying a social constructive process...... approach to leadership; a theoretical model emphasises that leadership emerges through social processes of recognition. Leadership is recognised by utilising the uncertainty of a wicked problem and innovation to influence collaborators’ sensemaking processes. The empirical setting is the City of Copenhagen...

  14. Bottom-up effects of a no-take zone on endangered penguin demographics.

    Science.gov (United States)

    Sherley, Richard B; Winker, Henning; Altwegg, Res; van der Lingen, Carl D; Votier, Stephen C; Crawford, Robert J M

    2015-07-01

    Marine no-take zones can have positive impacts for target species and are increasingly important management tools. However, whether they indirectly benefit higher order predators remains unclear. The endangered African penguin (Spheniscus demersus) depends on commercially exploited forage fish. We examined how chick survival responded to an experimental 3-year fishery closure around Robben Island, South Africa, controlling for variation in prey biomass and fishery catches. Chick survival increased by 18% when the closure was initiated, which alone led to a predicted 27% higher population compared with continued fishing. However, the modelled population continued to decline, probably because of high adult mortality linked to poor prey availability over larger spatial scales. Our results illustrate that small no-take zones can have bottom-up benefits for highly mobile marine predators, but are only one component of holistic, ecosystem-based management regimes. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

  15. Bottom-Up Meets Top-Down: Patchy Hybrid Nonwovens as an Efficient Catalysis Platform.

    Science.gov (United States)

    Schöbel, Judith; Burgard, Matthias; Hils, Christian; Dersch, Roland; Dulle, Martin; Volk, Kirsten; Karg, Matthias; Greiner, Andreas; Schmalz, Holger

    2017-01-02

    Heterogeneous catalysis with supported nanoparticles (NPs) is a highly active field of research. However, the efficient stabilization of NPs without deteriorating their catalytic activity is challenging. By combining top-down (coaxial electrospinning) and bottom-up (crystallization-driven self-assembly) approaches, we prepared patchy nonwovens with functional, nanometer-sized patches on the surface. These patches can selectively bind and efficiently stabilize gold nanoparticles (AuNPs). The use of these AuNP-loaded patchy nonwovens in the alcoholysis of dimethylphenylsilane led to full conversion under comparably mild conditions and in short reaction times. The absence of gold leaching or a slowing down of the reaction even after ten subsequent cycles manifests the excellent reusability of this catalyst system. The flexibility of the presented approach allows for easy transfer to other nonwoven supports and catalytically active NPs, which promises broad applicability. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Telecom-Wavelength Bottom-up Nanobeam Lasers on Silicon-on-Insulator.

    Science.gov (United States)

    Kim, Hyunseok; Lee, Wook-Jae; Farrell, Alan C; Balgarkashi, Akshay; Huffaker, Diana L

    2017-09-13

    Semiconductor nanowire lasers are considered promising ultracompact and energy-efficient light sources in the field of nanophotonics. Although the integration of nanowire lasers onto silicon photonic platforms is an innovative path toward chip-scale optical communications and photonic integrated circuits, operating nanowire lasers at telecom-wavelengths remains challenging. Here, we report on InGaAs nanowire array lasers on a silicon-on-insulator platform operating up to 1440 nm at room temperature. Bottom-up photonic crystal nanobeam cavities are formed by growing nanowires as ordered arrays using selective-area epitaxy, and single-mode lasing by optical pumping is demonstrated. We also show that arrays of nanobeam lasers with individually tunable wavelengths can be integrated on a single chip by the simple adjustment of the lithographically defined growth pattern. These results exemplify a practical approach toward nanowire lasers for silicon photonics.

  17. Bottom-up Synthesis of Porous NiMo Alloy for Hydrogen Evolution Reaction

    Directory of Open Access Journals (Sweden)

    Kailong Hu

    2018-01-01

    Full Text Available Bottom-up synthesis of porous NiMo alloy reduced by NiMoO4 nanofibers was systematically investigated to fabricate non-noble metal porous electrodes for hydrogen production. The different annealing temperatures of NiMoO4 nanofibers under hydrogen atmosphere reveal that the 950 °C annealing temperature is key for producing bicontinuous porous NiMo alloy without oxide phases. The porous NiMo alloy acts as a cathode in electrical water splitting, which demonstrates not only almost identical catalytic activity with commercial Pt/C in 1.0 M KOH solution, but also superb stability for 12 days at an electrode potential of −200 mV vs. reversible hydrogen electrode (RHE.

  18. Cognition from the bottom up: on biological inspiration, body morphology, and soft materials.

    Science.gov (United States)

    Pfeifer, Rolf; Iida, Fumiya; Lungarella, Max

    2014-08-01

    Traditionally, in cognitive science the emphasis is on studying cognition from a computational point of view. Studies in biologically inspired robotics and embodied intelligence, however, provide strong evidence that cognition cannot be analyzed and understood by looking at computational processes alone, but that physical system-environment interaction needs to be taken into account. In this opinion article, we review recent progress in cognitive developmental science and robotics, and expand the notion of embodiment to include soft materials and body morphology in the big picture. We argue that we need to build our understanding of cognition from the bottom up; that is, all the way from how our body is physically constructed. Copyright © 2014 Elsevier Ltd. All rights reserved.

  19. Bottom-up construction of a superstructure in a porous uranium-organic crystal

    Energy Technology Data Exchange (ETDEWEB)

    Li, Peng; Vermeulen, Nicolaas A.; Malliakas, Christos D.; G?mez-Gualdr?n, Diego A.; Howarth, Ashlee J.; Mehdi, B. Layla; Dohnalkova, Alice; Browning, Nigel D.; O?Keeffe, Michael; Farha, Omar K.

    2017-04-20

    Bottom-up construction of highly intricate structures from simple building blocks remains one of the most difficult challenges in chemistry. We report a structurally complex, mesoporous uranium-based metal-organic framework (MOF) made from simple starting components. The structure comprises 10 uranium nodes and seven tricarboxylate ligands (both crystallographically nonequivalent), resulting in a 173.3-angstrom cubic unit cell enclosing 816 uranium nodes and 816 organic linkers—the largest unit cell found to date for any nonbiological material. The cuboctahedra organize into pentagonal and hexagonal prismatic secondary structures, which then form tetrahedral and diamond quaternary topologies with unprecedented complexity. This packing results in the formation of colossal icosidodecahedral and rectified hexakaidecahedral cavities with internal diameters of 5.0 nanometers and 6.2 nanometers, respectively—ultimately giving rise to the lowest-density MOF reported to date.

  20. Strain Response of Hot-Mix Asphalt Overlays for Bottom-Up Reflective Cracking

    CERN Document Server

    Ghauch, Ziad G

    2011-01-01

    This paper examines the strain response of typical HMA overlays above jointed PCC slabs prone to bottom-up reflective cracking. The occurrence of reflective cracking under the combined effect of traffic and environmental loading significantly reduces the design life of the HMA overlays and can lead to its premature failure. In this context, viscoelastic material properties combined with cyclic vehicle loadings and pavement temperature distribution were implemented in a series of FE models in order to study the evolution of horizontal tensile and shear strains at the bottom of the HMA overlay. The effect of several design parameters, such as subbase and subgrade moduli, vehicle speed, overlay thickness, and temperature condition, on the horizontal and shear strain response was investigated. Results obtained show that the rate of horizontal and shear strain increase at the bottom of the HMA overlay drop with higher vehicle speed, higher subgrade modulus, and higher subbase modulus. Moreover, the rate of horizon...

  1. Multisegment injections improve peptide identification rates in capillary zone electrophoresis-based bottom-up proteomics.

    Science.gov (United States)

    Boley, Danielle A; Zhang, Zhenbin; Dovichi, Norman J

    2017-11-10

    While capillary zone electrophoresis (CZE) provides dramatically improved numbers of peptide identifications compared with reversed-phase chromatography for bottom-up proteomics of mass limited samples, CZE inevitably produces lower numbers of peptide identifications than RPLC for larger samples. One reason for this poorer performance is the dead time between injection of samples and subsequent appearance of the fastest moving component. This dead time is typically 25% of the separation window in CZE, but is only 5% of the separation window in gradient elution RPLC. This dead time can be eliminated in CZE by use of a multisegment injection mode where a series of samples is analyzed by injecting each sample while the preceding sample is still being separated. In this paper, we demonstrate that capillary zone electrophoresis employing sequential injections can produce a doubling in peptide identification rate with no degradation in separation efficiency. Copyright © 2017 Elsevier B.V. All rights reserved.

  2. Bottom-Up Nanofabrication of Supported Noble Metal Alloy Nanoparticle Arrays for Plasmonics

    DEFF Research Database (Denmark)

    Nugroho, Ferry A. A.; Iandolo, Beniamino; Wagner, Jakob Birkedal

    2016-01-01

    Mixing different elements at the nanoscale to obtain alloy nanostructures with fine-tuned physical and chemical properties offers appealing opportunities for nanotechnology and nanoscience. However, despite widespread successful application of alloy nanoparticles made by colloidal synthesis...... in heterogeneous catalysis, nanoalloy systems have been used very rarely in solid-state devices and nanoplasmonics-related applications. One reason is that such applications require integration in arrays on a surface with compelling demands on nanoparticle arrangement, uniformity in surface coverage......, and optimization of the surface density. These cannot be fulfilled even using state-of-the-art self -assembly strategies of colloids. As a solution, we present here a generic bottom-up nanolithography-compatible fabrication approach for large-area arrays of alloy nanoparticles on surfaces. To illustrate...

  3. Reconciling bottom-up, top-down, and direct measurements of biogenic VOC emissions

    Science.gov (United States)

    Guenther, A.; Karl, T.; Wiedinmyer, C.; Barkley, M.; Palmer, P.; Muller, J. F.; Stavrakov, T.; Millet, D.

    2007-12-01

    Biogenic Volatile Organic compound (BVOC) emissions vary considerably on spatial scales ranging from a few meters to thousands of kilometers and temporal scales ranging from seconds to years. Accurate estimates of BVOC emissions are required for many regional air quality modeling studies and global earth system investigations. We compare results from bottom-up estimates, using The Model of Emissions of Gases and Aerosols from Nature (MEGAN), with top-down estimates, based on satellite and in-situ concentration distributions, and direct flux measurements. We describe examples of both agreement and disagreement in U.S., tropical forest and other landscapes and discuss potential explanations for differences that can exceed a factor of 2. Future measurement and modeling needs are outlined and specific activities are proposed to improve efforts to reconcile these approaches and understand the controlling processes.

  4. Sequential bottom-up assembly of mechanically stabilized synthetic cells by microfluidics

    Science.gov (United States)

    Weiss, Marian; Frohnmayer, Johannes Patrick; Benk, Lucia Theresa; Haller, Barbara; Janiesch, Jan-Willi; Heitkamp, Thomas; Börsch, Michael; Lira, Rafael B.; Dimova, Rumiana; Lipowsky, Reinhard; Bodenschatz, Eberhard; Baret, Jean-Christophe; Vidakovic-Koch, Tanja; Sundmacher, Kai; Platzman, Ilia; Spatz, Joachim P.

    2018-01-01

    Compartments for the spatially and temporally controlled assembly of biological processes are essential towards cellular life. Synthetic mimics of cellular compartments based on lipid-based protocells lack the mechanical and chemical stability to allow their manipulation into a complex and fully functional synthetic cell. Here, we present a high-throughput microfluidic method to generate stable, defined sized liposomes termed `droplet-stabilized giant unilamellar vesicles (dsGUVs)’. The enhanced stability of dsGUVs enables the sequential loading of these compartments with biomolecules, namely purified transmembrane and cytoskeleton proteins by microfluidic pico-injection technology. This constitutes an experimental demonstration of a successful bottom-up assembly of a compartment with contents that would not self-assemble to full functionality when simply mixed together. Following assembly, the stabilizing oil phase and droplet shells are removed to release functional self-supporting protocells to an aqueous phase, enabling them to interact with physiologically relevant matrices.

  5. Mesoporous ZSM-5 Zeolites in Acid Catalysis: Top-Down vs. Bottom-Up Approach

    Directory of Open Access Journals (Sweden)

    Pit Losch

    2017-07-01

    Full Text Available A top-down desilication of Al-rich ZSM-5 zeolites and a bottom-up mesopores creating method were evaluated in this study. Three liquid–solid and one gas–solid heterogeneously-catalysed reactions were chosen to establish relationships between zeolites textural properties and their catalytic behavior in acid-catalysed model reactions that are influenced by shape selectivity: Diels-Alder cyclization between isoprene and methylacrylate, Methanol-to-Olefins (MTO reaction, chlorination of iodobenzene with trichloroisocyanuric acid (TCCA, and Friedel-Crafts acylation of anisole by carboxylic acids with differing sizes. It is found amongst others that no optimal mesoporosity for all the different reactions can be easily obtained, but depending on the chosen application, a specific treatment has to be set to achieve high activity/selectivity and stability.

  6. Bottom-Up Cost Analysis of a High Concentration PV Module; NREL (National Renewable Energy Laboratory)

    Energy Technology Data Exchange (ETDEWEB)

    Horowitz, K.; Woodhouse, M.; Lee, H.; Smestad, G.

    2015-04-13

    We present a bottom-up model of III-V multi-junction cells, as well as a high concentration PV (HCPV) module. We calculate $0.65/Wp(DC) manufacturing costs for our model HCPV module design with today’s capabilities, and find that reducing cell costs and increasing module efficiency offer the promising pathways for future cost reductions. Cell costs could be significantly reduced via an increase in manufacturing scale, substrate reuse, and improved manufacturing yields. We also identify several other significant drivers of HCPV module costs, including the Fresnel lens primary optic, module housing, thermal management, and the receiver board. These costs could potentially be lowered by employing innovative module designs.

  7. Sequential bottom-up assembly of mechanically stabilized synthetic cells by microfluidics.

    Science.gov (United States)

    Weiss, Marian; Frohnmayer, Johannes Patrick; Benk, Lucia Theresa; Haller, Barbara; Janiesch, Jan-Willi; Heitkamp, Thomas; Börsch, Michael; Lira, Rafael B; Dimova, Rumiana; Lipowsky, Reinhard; Bodenschatz, Eberhard; Baret, Jean-Christophe; Vidakovic-Koch, Tanja; Sundmacher, Kai; Platzman, Ilia; Spatz, Joachim P

    2017-10-16

    Compartments for the spatially and temporally controlled assembly of biological processes are essential towards cellular life. Synthetic mimics of cellular compartments based on lipid-based protocells lack the mechanical and chemical stability to allow their manipulation into a complex and fully functional synthetic cell. Here, we present a high-throughput microfluidic method to generate stable, defined sized liposomes termed 'droplet-stabilized giant unilamellar vesicles (dsGUVs)'. The enhanced stability of dsGUVs enables the sequential loading of these compartments with biomolecules, namely purified transmembrane and cytoskeleton proteins by microfluidic pico-injection technology. This constitutes an experimental demonstration of a successful bottom-up assembly of a compartment with contents that would not self-assemble to full functionality when simply mixed together. Following assembly, the stabilizing oil phase and droplet shells are removed to release functional self-supporting protocells to an aqueous phase, enabling them to interact with physiologically relevant matrices.

  8. Collective Inclusioning: A Grounded Theory of a Bottom-Up Approach to Innovation and Leading

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    Michal Lysek

    2016-06-01

    Full Text Available This paper is a grounded theory study of how leaders (e.g., entrepreneurs, managers, etc. engage people in challenging undertakings (e.g., innovation that require everyone’s commitment to such a degree that they would have to go beyond what could be reasonably expected in order to succeed. Company leaders sometimes wonder why their employees no longer show the same responsibility towards their work, and why they are more concerned with internal politics than solving customer problems. It is because company leaders no longer apply collective inclusioning to the same extent as they did in the past. Collective inclusioning can be applied in four ways by convincing, afinitizing, goal congruencing, and engaging. It can lead to fostering strong units of people for taking on challenging undertakings. Collective inclusioning is a complementing theory to other strategic management and leading theories. It offers a new perspective on how to implement a bottom-up approach to innovation.

  9. Ecology of Caribbean sponges: are top-down or bottom-up processes more important?

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    Michael P Lesser

    Full Text Available Benthic-pelagic coupling and the role of bottom-up versus top-down processes are recognized as having a major impact on the structure of marine communities. While the roles of bottom-up processes are better appreciated they are still viewed as principally affecting the outcome of top-down processes. Sponges on coral reefs are important members of the benthic community and provide a critically important functional linkage between water-column productivity and the benthos. As active suspension feeders sponges utilize the abundant autotrophic and heterotrophic picoplankton in the water column. As a result sponges across the Caribbean basin exhibit a consistent and significant pattern of greater biomass, tube extension rate, and species numbers with increasing depth. Likewise, the abundance of their food supply also increases along a depth gradient. Using experimental manipulations it has recently been reported that predation is the primary determinant of sponge community structure. Here we provide data showing that the size and growth of the sponge Callyspongia vaginalis are significantly affected by food availability. Sponges increased in size and tube extension rate with increasing depth down to 46 m, while simultaneously exposed to the full range of potential spongivores at all depths. Additionally, we point out important flaws in the experimental design used to demonstrate the role of predation and suggest that a resolution of this important question will require well-controlled, multi-factorial experiments to examine the independent and interactive effects of predation and food abundance on the ecology of sponges.

  10. Intracellular bottom-up generation of targeted nanosensors for single-molecule imaging

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    Hou, Yanyan; Arai, Satoshi; Kitaguchi, Tetsuya; Suzuki, Madoka

    2016-02-01

    Organic dyes are useful tools for sensing cellular activities but unfavorable in single-molecule imaging, whereas quantum dots (QDs) are widely applied in single-molecule imaging but with few sensing applications. Here, to visualize cellular activities by monitoring the response of a single probe in living cells, we propose a bottom-up approach to generate nanoprobes where four organic dyes are conjugated to tetravalent single-chain avidin (scAVD) proteins via an intracellular click reaction. We demonstrate that the nanoprobes, exhibiting increased brightness and enhanced photostability, were detectable as single dots in living cells. The ease of intracellular targeting allowed the tracking of endoplasmic reticulum (ER) remodeling with nanometer spatial resolution. Conjugating thermosensitive dyes generated temperature-sensitive nanoprobes on ER membranes that successfully monitored local temperature changes in response to external heat pulses. Our approach is potentially a suitable tool for visualizing localized cellular activities with single probe sensitivity in living cells.Organic dyes are useful tools for sensing cellular activities but unfavorable in single-molecule imaging, whereas quantum dots (QDs) are widely applied in single-molecule imaging but with few sensing applications. Here, to visualize cellular activities by monitoring the response of a single probe in living cells, we propose a bottom-up approach to generate nanoprobes where four organic dyes are conjugated to tetravalent single-chain avidin (scAVD) proteins via an intracellular click reaction. We demonstrate that the nanoprobes, exhibiting increased brightness and enhanced photostability, were detectable as single dots in living cells. The ease of intracellular targeting allowed the tracking of endoplasmic reticulum (ER) remodeling with nanometer spatial resolution. Conjugating thermosensitive dyes generated temperature-sensitive nanoprobes on ER membranes that successfully monitored local

  11. Platform Dependencies in Bottom-up Hydrogen/Deuterium Exchange Mass Spectrometry*

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    Burns, Kyle M.; Rey, Martial; Baker, Charles A. H.; Schriemer, David C.

    2013-01-01

    Hydrogen-deuterium exchange mass spectrometry is an important method for protein structure-function analysis. The bottom-up approach uses protein digestion to localize deuteration to higher resolution, and the essential measurement involves centroid mass determinations on a very large set of peptides. In the course of evaluating systems for various projects, we established two (HDX-MS) platforms that consisted of a FT-MS and a high-resolution QTOF mass spectrometer, each with matched front-end fluidic systems. Digests of proteins spanning a 20–110 kDa range were deuterated to equilibrium, and figures-of-merit for a typical bottom-up (HDX-MS) experiment were compared for each platform. The Orbitrap Velos identified 64% more peptides than the 5600 QTOF, with a 42% overlap between the two systems, independent of protein size. Precision in deuterium measurements using the Orbitrap marginally exceeded that of the QTOF, depending on the Orbitrap resolution setting. However, the unique nature of FT-MS data generates situations where deuteration measurements can be inaccurate, because of destructive interference arising from mismatches in elemental mass defects. This is shown through the analysis of the peptides common to both platforms, where deuteration values can be as low as 35% of the expected values, depending on FT-MS resolution, peptide length and charge state. These findings are supported by simulations of Orbitrap transients, and highlight that caution should be exercised in deriving centroid mass values from FT transients that do not support baseline separation of the full isotopic composition. PMID:23197788

  12. Perceptual salience affects the contents of working memory during free-recollection of objects from natural scenes

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    Tiziana ePedale

    2015-02-01

    Full Text Available One of the most important issues in the study of cognition is to understand which are the factors determining internal representation of the external world. Previous literature has started to highlight the impact of low-level sensory features (indexed by saliency-maps in driving attention selection, hence increasing the probability for objects presented in complex and natural scenes to be successfully encoded into working memory(WM and then correctly remembered. Here we asked whether the probability of retrieving high-saliency objects modulates the overall contents of WM, by decreasing the probability of retrieving other, lower-saliency objects. We presented pictures of natural scenes for 4 secs. After a retention period of 8 secs, we asked participants to verbally report as many objects/details as possible of the previous scenes. We then computed how many times the objects located at either the peak of maximal or minimal saliency in the scene (as indexed by a saliency-map; Itti et al., 1998 were recollected by participants. Results showed that maximal-saliency objects were recollected more often and earlier in the stream of successfully reported items than minimal-saliency objects. This indicates that bottom-up sensory salience increases the recollection probability and facilitates the access to memory representation at retrieval, respectively. Moreover, recollection of the maximal- (but not the minimal- saliency objects predicted the overall amount of successfully recollected objects: The higher the probability of having successfully reported the most-salient object in the scene, the lower the amount of recollected objects. These findings highlight that bottom-up sensory saliency modulates the current contents of WM during recollection of objects from natural scenes, most likely by reducing available resources to encode and then retrieve other (lower saliency objects.

  13. Bottom-up and top-down influences at untrained conditions determine perceptual learning specificity and transfer.

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    Xiong, Ying-Zi; Zhang, Jun-Yun; Yu, Cong

    2016-07-05

    Perceptual learning is often orientation and location specific, which may indicate neuronal plasticity in early visual areas. However, learning specificity diminishes with additional exposure of the transfer orientation or location via irrelevant tasks, suggesting that the specificity is related to untrained conditions, likely because neurons representing untrained conditions are neither bottom-up stimulated nor top-down attended during training. To demonstrate these top-down and bottom-up contributions, we applied a "continuous flash suppression" technique to suppress the exposure stimulus into sub-consciousness, and with additional manipulations to achieve pure bottom-up stimulation or top-down attention with the transfer condition. We found that either bottom-up or top-down influences enabled significant transfer of orientation and Vernier discrimination learning. These results suggest that learning specificity may result from under-activations of untrained visual neurons due to insufficient bottom-up stimulation and/or top-down attention during training. High-level perceptual learning thus may not functionally connect to these neurons for learning transfer.

  14. Getting to the bottom of L2 listening instruction: Making a case for bottom-up activities

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    Joseph Siegel

    2015-12-01

    Full Text Available This paper argues for the incorporation of bottom-up activities for English as a foreign language (EFL listening. It discusses theoretical concepts and pedagogic options for addressing bottom-up aural processing in the EFL classroom as well as how and why teachers may wish to include such activities in lessons. This discussion is augmented by a small-scale classroom-based research project that investigated six activities targeting learners’ bottom-up listening abilities. Learners studying at the lower-intermediate level of a compulsory EFL university course were divided into a treatment group (n = 21 and a contrast group (n = 32. Each group listened to the same audio material and completed listening activities from an assigned textbook. The treatment group also engaged in a set of six bottom-up listening activities using the same material. This quasi-experimental study used dictation and listening proficiency tests before and after the course. Between-group comparisons of t-test results of dictation and listening proficiency tests indicated that improvements for the treatment group were probably due to the BU intervention. In addition, results from a posttreatment survey suggested that learners value explicit bottom-up listening instruction.

  15. Pressurized Pepsin Digestion in Proteomics: An Automatable Alternative to Trypsin for Integrated Top-down Bottom-up Proteomics

    Energy Technology Data Exchange (ETDEWEB)

    Lopez-Ferrer, Daniel; Petritis, Konstantinos; Robinson, Errol W.; Hixson, Kim K.; Tian, Zhixin; Lee, Jung Hwa; Lee, Sang-Won; Tolic, Nikola; Weitz, Karl K.; Belov, Mikhail E.; Smith, Richard D.; Pasa-Tolic, Ljiljana

    2011-02-01

    Integrated top-down bottom-up proteomics combined with online digestion has great potential to improve the characterization of protein isoforms in biological systems and is amendable to highthroughput proteomics experiments. Bottom-up proteomics ultimately provides the peptide sequences derived from the tandem MS analyses of peptides after the proteome has been digested. Top-down proteomics conversely entails the MS analyses of intact proteins for more effective characterization of genetic variations and/or post-translational modifications (PTMs). Herein, we describe recent efforts towards efficient integration of bottom-up and top-down LCMS based proteomic strategies. Since most proteomic platforms (i.e. LC systems) operate in acidic environments, we exploited the compatibility of the pepsin (i.e. the enzyme’s natural acidic activity) for the integration of bottom-up and top-down proteomics. Pressure enhanced pepsin digestions were successfully performed and characterized with several standard proteins in either an offline mode using a Barocycler or an online mode using a modified high pressure LC system referred to as a fast online digestion system (FOLDS). FOLDS was tested using pepsin and a whole microbial proteome, and the results compared against traditional trypsin digestions on the same platform. Additionally, FOLDS was integrated with a RePlay configuration to demonstrate an ultra-rapid integrated bottom-up top-down proteomic strategy employing a standard mixture of proteins and a monkey pox virus proteome.

  16. A bottom-up approach to estimating cost elements of REDD+ pilot projects in Tanzania.

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    Merger, Eduard; Held, Christian; Tennigkeit, Timm; Blomley, Tom

    2012-08-09

    Several previous global REDD+ cost studies have been conducted, demonstrating that payments for maintaining forest carbon stocks have significant potential to be a cost-effective mechanism for climate change mitigation. These studies have mostly followed highly aggregated top-down approaches without estimating the full range of REDD+ costs elements, thus underestimating the actual costs of REDD+. Based on three REDD+ pilot projects in Tanzania, representing an area of 327,825 ha, this study explicitly adopts a bottom-up approach to data assessment. By estimating opportunity, implementation, transaction and institutional costs of REDD+ we develop a practical and replicable methodological framework to consistently assess REDD+ cost elements. Based on historical land use change patterns, current region-specific economic conditions and carbon stocks, project-specific opportunity costs ranged between US$ -7.8 and 28.8 tCOxxxx for deforestation and forest degradation drivers such as agriculture, fuel wood production, unsustainable timber extraction and pasture expansion. The mean opportunity costs for the three projects ranged between US$ 10.1 - 12.5 tCO2. Implementation costs comprised between 89% and 95% of total project costs (excluding opportunity costs) ranging between US$ 4.5 - 12.2 tCO2 for a period of 30 years. Transaction costs for measurement, reporting, verification (MRV), and other carbon market related compliance costs comprised a minor share, between US$ 0.21 - 1.46 tCO2. Similarly, the institutional costs comprised around 1% of total REDD+ costs in a range of US$ 0.06 - 0.11 tCO2. The use of bottom-up approaches to estimate REDD+ economics by considering regional variations in economic conditions and carbon stocks has been shown to be an appropriate approach to provide policy and decision-makers robust economic information on REDD+. The assessment of opportunity costs is a crucial first step to provide information on the economic baseline situation of

  17. A bottom-up approach to estimating cost elements of REDD+ pilot projects in Tanzania

    Directory of Open Access Journals (Sweden)

    Merger Eduard

    2012-08-01

    Full Text Available Abstract Background Several previous global REDD+ cost studies have been conducted, demonstrating that payments for maintaining forest carbon stocks have significant potential to be a cost-effective mechanism for climate change mitigation. These studies have mostly followed highly aggregated top-down approaches without estimating the full range of REDD+ costs elements, thus underestimating the actual costs of REDD+. Based on three REDD+ pilot projects in Tanzania, representing an area of 327,825 ha, this study explicitly adopts a bottom-up approach to data assessment. By estimating opportunity, implementation, transaction and institutional costs of REDD+ we develop a practical and replicable methodological framework to consistently assess REDD+ cost elements. Results Based on historical land use change patterns, current region-specific economic conditions and carbon stocks, project-specific opportunity costs ranged between US$ -7.8 and 28.8 tCOxxxx for deforestation and forest degradation drivers such as agriculture, fuel wood production, unsustainable timber extraction and pasture expansion. The mean opportunity costs for the three projects ranged between US$ 10.1 – 12.5 tCO2. Implementation costs comprised between 89% and 95% of total project costs (excluding opportunity costs ranging between US$ 4.5 - 12.2 tCO2 for a period of 30 years. Transaction costs for measurement, reporting, verification (MRV, and other carbon market related compliance costs comprised a minor share, between US$ 0.21 - 1.46 tCO2. Similarly, the institutional costs comprised around 1% of total REDD+ costs in a range of US$ 0.06 – 0.11 tCO2. Conclusions The use of bottom-up approaches to estimate REDD+ economics by considering regional variations in economic conditions and carbon stocks has been shown to be an appropriate approach to provide policy and decision-makers robust economic information on REDD+. The assessment of opportunity costs is a crucial first step to

  18. Bottom-Up Abstract Modelling of Optical Networks-on-Chip: From Physical to Architectural Layer

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    Alberto Parini

    2012-01-01

    Full Text Available This work presents a bottom-up abstraction procedure based on the design-flow FDTD + SystemC suitable for the modelling of optical Networks-on-Chip. In this procedure, a complex network is decomposed into elementary switching elements whose input-output behavior is described by means of scattering parameters models. The parameters of each elementary block are then determined through 2D-FDTD simulation, and the resulting analytical models are exported within functional blocks in SystemC environment. The inherent modularity and scalability of the S-matrix formalism are preserved inside SystemC, thus allowing the incremental composition and successive characterization of complex topologies typically out of reach for full-vectorial electromagnetic simulators. The consistency of the outlined approach is verified, in the first instance, by performing a SystemC analysis of a four-input, four-output ports switch and making a comparison with the results of 2D-FDTD simulations of the same device. Finally, a further complex network encompassing 160 microrings is investigated, the losses over each routing path are calculated, and the minimum amount of power needed to guarantee an assigned BER is determined. This work is a basic step in the direction of an automatic technology-aware network-level simulation framework capable of assembling complex optical switching fabrics, while at the same time assessing the practical feasibility and effectiveness at the physical/technological level.

  19. Programmable chemical reaction networks: emulating regulatory functions in living cells using a bottom-up approach.

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    van Roekel, Hendrik W H; Rosier, Bas J H M; Meijer, Lenny H H; Hilbers, Peter A J; Markvoort, Albert J; Huck, Wilhelm T S; de Greef, Tom F A

    2015-11-07

    Living cells are able to produce a wide variety of biological responses when subjected to biochemical stimuli. It has become apparent that these biological responses are regulated by complex chemical reaction networks (CRNs). Unravelling the function of these circuits is a key topic of both systems biology and synthetic biology. Recent progress at the interface of chemistry and biology together with the realisation that current experimental tools are insufficient to quantitatively understand the molecular logic of pathways inside living cells has triggered renewed interest in the bottom-up development of CRNs. This builds upon earlier work of physical chemists who extensively studied inorganic CRNs and showed how a system of chemical reactions can give rise to complex spatiotemporal responses such as oscillations and pattern formation. Using purified biochemical components, in vitro synthetic biologists have started to engineer simplified model systems with the goal of mimicking biological responses of intracellular circuits. Emulation and reconstruction of system-level properties of intracellular networks using simplified circuits are able to reveal key design principles and molecular programs that underlie the biological function of interest. In this Tutorial Review, we present an accessible overview of this emerging field starting with key studies on inorganic CRNs followed by a discussion of recent work involving purified biochemical components. Finally, we review recent work showing the versatility of programmable biochemical reaction networks (BRNs) in analytical and diagnostic applications.

  20. Enhanced Photon Extraction from a Nanowire Quantum Dot Using a Bottom-Up Photonic Shell

    Science.gov (United States)

    Jeannin, Mathieu; Cremel, Thibault; Häyrynen, Teppo; Gregersen, Niels; Bellet-Amalric, Edith; Nogues, Gilles; Kheng, Kuntheak

    2017-11-01

    Semiconductor nanowires offer the possibility to grow high-quality quantum-dot heterostructures, and, in particular, CdSe quantum dots inserted in ZnSe nanowires have demonstrated the ability to emit single photons up to room temperature. In this paper, we demonstrate a bottom-up approach to fabricate a photonic fiberlike structure around such nanowire quantum dots by depositing an oxide shell using atomic-layer deposition. Simulations suggest that the intensity collected in our NA =0.6 microscope objective can be increased by a factor 7 with respect to the bare nanowire case. Combining microphotoluminescence, decay time measurements, and numerical simulations, we obtain a fourfold increase in the collected photoluminescence from the quantum dot. We show that this improvement is due to an increase of the quantum-dot emission rate and a redirection of the emitted light. Our ex situ fabrication technique allows a precise and reproducible fabrication on a large scale. Its improved extraction efficiency is compared to state-of-the-art top-down devices.

  1. To elute or not to elute in immunocapture bottom-up LC-MS.

    Science.gov (United States)

    Levernæs, Maren Christin Stillesby; Broughton, Marianne Nordlund; Reubsaet, Léon; Halvorsen, Trine Grønhaug

    2017-06-15

    Immunocapture-based bottom-up LC-MS is a promising technique for the quantification of low abundant proteins. Magnetic immunocapture beads provide efficient enrichment from complex samples through the highly specific interaction between the target protein and its antibody. In this article, we have performed the first thorough comparison between digestion of proteins while bound to antibody coated beads versus after elution from the beads. Two previously validated immunocapture based MS methods for the quantification of pro-gastrin releasing peptide (ProGRP) and human chorionic gonadotropin (hCG) were used as model systems. The tryptic peptide generation was shown to be protein dependent and influenced by protein folding and accessibility towards trypsin both on-beads and in the eluate. The elution of proteins bound to the beads was also shown to be incomplete. In addition, the on-beads digestion suffered from non-specific binding of the trypsin generated peptides. A combination of on-beads digestion and elution may be applied to improve both the quantitative (peak area of the signature peptides) and qualitative yield (number of missed cleavages, total number of identified peptides, coverage, signal intensity and number of zero missed cleavage peptides) of the target proteins. The quantitative yield of signature peptides was shown to be reproducible in all procedures tested. Copyright © 2017 Elsevier B.V. All rights reserved.

  2. Top-down network analysis to drive bottom-up modeling of physiological processes.

    Science.gov (United States)

    Poirel, Christopher L; Rodrigues, Richard R; Chen, Katherine C; Tyson, John J; Murali, T M

    2013-05-01

    Top-down analyses in systems biology can automatically find correlations among genes and proteins in large-scale datasets. However, it is often difficult to design experiments from these results. In contrast, bottom-up approaches painstakingly craft detailed models that can be simulated computationally to suggest wet lab experiments. However, developing the models is a manual process that can take many years. These approaches have largely been developed independently. We present LINKER, an efficient and automated data-driven method that can analyze molecular interactomes to propose extensions to models that can be simulated. LINKER combines teleporting random walks and k-shortest path computations to discover connections from a source protein to a set of proteins collectively involved in a particular cellular process. We evaluate the efficacy of LINKER by applying it to a well-known dynamic model of the cell division cycle in Saccharomyces cerevisiae. Compared to other state-of-the-art methods, subnetworks computed by LINKER are heavily enriched in Gene Ontology (GO) terms relevant to the cell cycle. Finally, we highlight how networks computed by LINKER elucidate the role of a protein kinase (Cdc5) in the mitotic exit network of a dynamic model of the cell cycle.

  3. Bottom-up Retinotopic Organization Supports Top-down Mental Imagery.

    Science.gov (United States)

    Huang, Ruey-Song; Sereno, Martin I

    2013-01-01

    Finding a path between locations is a routine task in daily life. Mental navigation is often used to plan a route to a destination that is not visible from the current location. We first used functional magnetic resonance imaging (fMRI) and surface-based averaging methods to find high-level brain regions involved in imagined navigation between locations in a building very familiar to each participant. This revealed a mental navigation network that includes the precuneus, retrosplenial cortex (RSC), parahippocampal place area (PPA), occipital place area (OPA), supplementary motor area (SMA), premotor cortex, and areas along the medial and anterior intraparietal sulcus. We then visualized retinotopic maps in the entire cortex using wide-field, natural scene stimuli in a separate set of fMRI experiments. This revealed five distinct visual streams or 'fingers' that extend anteriorly into middle temporal, superior parietal, medial parietal, retrosplenial and ventral occipitotemporal cortex. By using spherical morphing to overlap these two data sets, we showed that the mental navigation network primarily occupies areas that also contain retinotopic maps. Specifically, scene-selective regions RSC, PPA and OPA have a common emphasis on the far periphery of the upper visual field. These results suggest that bottom-up retinotopic organization may help to efficiently encode scene and location information in an eye-centered reference frame for top-down, internally generated mental navigation. This study pushes the border of visual cortex further anterior than was initially expected.

  4. Bottom-up Perspectives on Multilingual Ideologies in the EU: The Case of a Transnational NGO

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    Franco Zappettini

    2014-11-01

    Full Text Available This paper investigates the discursive construction of multilingualism in citizens’ discourses, aiming to fill a gap in the literature of European studies that has scarcely been concerned with language ideologies from bottom-up perspectives. In particular, we focus on the discourses of a transnational NGO to analyse how its members position themselves in relation to linguistic issues and to what extent (if so they reproduce the EU’s multilingual ideology. Deriving data from focus groups and semi-structured interviews, we contextualise our analysis against the backdrop of an increasingly ‘glocalised’ European site of struggle between global communication and linguistic justice. Using critical discourse analysis we aim to show how discourses of multilingualism are being negotiated at the grass-roots level. Our findings suggest that whilst citizens’ discourses validate an ideal promotion and preservation of linguistic diversity in the EU, they also endorse a diglossic scenario with language performing separate identity and communicative functions. We thus argue for an understanding of European multilingualism that takes into account the transnational dynamics of the European sphere.

  5. A "bottom up" governance framework for developing Australia's marine Spatial Data Infrastructure (SDI

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    K T Finney

    2007-07-01

    Full Text Available Spatial Data Infrastructures (SDIs have been developing in some countries for over 10 years but still suffer from having a relatively small installed base. Most SDIs will soon converge around a service-oriented-architecture (SOA using IT standards promulgated primarily by the Open Geospatial Consortium (OGC and ISO Technical Committee 211. There are very few examples of these types of architected SDIs in action, and as a result little detailed information exists on suitable governance models. This paper discusses the governance issues that are posed by SOA-based SDIs, particularly those issues surrounding standards and services management, with reference to an Australian marine case study and the general literature. A generalised governance framework is then postulated using an idealised use case model which is applicable for "bottom-up," community-based initiatives. This model incorporates guiding principles and motivational and self-regulation instruments that are characteristically found in successful open source development activities. It is argued that harnessing an open development model, using a voluntary workforce, could rapidly increase the size of the SDI installed base and importantly defray infrastructure build costs.

  6. Optical and electronic properties study of bottom-up graphene nanoribbons for photovoltaic applications

    Science.gov (United States)

    Villegas, Cesar E. P.; Rocha, Alexandre

    2015-03-01

    Graphene nanoribbons (GNRs), turn out to be serious contender for several optolectronic applications due to their physical properties. Recently, bottom-up methods, using the assembly of appropriate precursor molecules were shown to be an exciting pathway towards making precise nanoribbons. In particular, it has been demonstrated that so-called cove-shaped GNRs absorb light in the visible part of the spectrum, suggesting they could be used for photovoltaic applications. In solar cells, the key ingredient is the presence excitons and their subsequent diffusion along a donor material. This is influenced by the character of the different excitations taking place, as well as, the exciton binding energy. Thus, In this work we use many-body corrected density functional theory to simulate the optical properties of these nanoribbons. We elucidate the most important transitions occurring in these systems, and identify types of excitatiions that have not been previously observed in conventional nanoribbons. We also find that the exciton binding energies for all the structures we considered are in the eV range, which enhances the diffusion lengths for the particle-hole pairs. Finally, we estimate the potencial of these systems as solar cells by calculating the short-circuit current. The Authors thank FAPESP for financial support.

  7. Suspension trapping (STrap) sample preparation method for bottom-up proteomics analysis.

    Science.gov (United States)

    Zougman, Alexandre; Selby, Peter J; Banks, Rosamonde E

    2014-05-01

    Despite recent developments in bottom-up proteomics, the need still exists in a fast, uncomplicated, and robust method for comprehensive sample processing especially when applied to low protein amounts. The suspension trapping method combines the advantage of efficient SDS-based protein extraction with rapid detergent removal, reactor-type protein digestion, and peptide cleanup. Proteins are solubilized in SDS. The sample is acidified and introduced into the suspension trapping tip incorporating the depth filter and hydrophobic compartments, filled with the neutral pH methanolic solution. The instantly formed fine protein suspension is trapped in the depth filter stack-this crucial step is aimed at separating the particulate matter in space. SDS and other contaminants are removed in the flow-through, and a protease is introduced. Following the digestion, the peptides are cleaned up using the tip's hydrophobic part. The methodology allows processing of protein loads down to the low microgram/submicrogram levels. The detergent removal takes about 5 min, whereas the tryptic proteolysis of a cellular lysate is complete in as little as 30 min. We have successfully utilized the method for analysis of cellular lysates, enriched membrane preparations, and immunoprecipitates. We expect that due to its robustness and simplicity, the method will become an essential proteomics tool. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Rational design of modular circuits for gene transcription: A test of the bottom-up approach

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    Giordano Emanuele

    2010-11-01

    Full Text Available Abstract Background Most of synthetic circuits developed so far have been designed by an ad hoc approach, using a small number of components (i.e. LacI, TetR and a trial and error strategy. We are at the point where an increasing number of modular, inter-changeable and well-characterized components is needed to expand the construction of synthetic devices and to allow a rational approach to the design. Results We used interchangeable modular biological parts to create a set of novel synthetic devices for controlling gene transcription, and we developed a mathematical model of the modular circuits. Model parameters were identified by experimental measurements from a subset of modular combinations. The model revealed an unexpected feature of the lactose repressor system, i.e. a residual binding affinity for the operator site by induced lactose repressor molecules. Once this residual affinity was taken into account, the model properly reproduced the experimental data from the training set. The parameters identified in the training set allowed the prediction of the behavior of networks not included in the identification procedure. Conclusions This study provides new quantitative evidences that the use of independent and well-characterized biological parts and mathematical modeling, what is called a bottom-up approach to the construction of gene networks, can allow the design of new and different devices re-using the same modular parts.

  9. A 'bottom-up' approach to aetiological research in autism spectrum disorders

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    Lisa Marie Unwin

    2013-09-01

    Full Text Available Autism Spectrum Disorders (ASD are currently diagnosed in the presence of impairments in social interaction and communication, and a restricted range of activities and interests. However, there is considerable variability in the behaviours of different individuals with an ASD diagnosis. The heterogeneity spans the entire range of IQ and language abilities, as well as other behavioural, communicative and social functions. While any psychiatric condition is likely to incorporate a degree of heterogeneity, the variability in the nature and severity of behaviours observed in ASD is thought to exceed that of other disorders. The current paper aims to provide a model for future research into ASD subgroups. In doing so, we examined whether two proposed risk factors – low birth weight (LBW, and in-utero exposure to selective serotonin reuptake inhibitors (SSRIs – are associated with greater behavioural homogeneity. Using data from the Western Australian Autism Biological Registry, this study found that LBW and maternal SSRI use during pregnancy were associated with greater sleep disturbances and a greater number of gastrointestinal complaints in children with ASD, respectively. The findings from this ‘proof of principle’ paper provide support for this 'bottom-up' approach as a feasible method for creating homogenous groups.

  10. Bottom-Up Two-Dimensional Electron-Capture Dissociation Mass Spectrometry of Calmodulin

    Science.gov (United States)

    Floris, Federico; van Agthoven, Maria A.; Chiron, Lionel; Wootton, Christopher A.; Lam, Pui Yiu Yuko; Barrow, Mark P.; Delsuc, Marc-André; O'Connor, Peter B.

    2017-10-01

    Two-dimensional mass spectrometry (2D MS) is a tandem mass spectrometry technique that allows data-independent fragmentation of all precursors in a mixture without previous isolation, through modulation of the ion cyclotron frequency in the ICR-cell prior to fragmentation. Its power as an analytical technique has been proven particularly for proteomics. Recently, a comparison study between 1D and 2D MS has been performed using infrared multiphoton dissociation (IRMPD) on calmodulin (CaM), highlighting the capabilities of the technique in both top-down (TDP) and bottom-up proteomics (BUP). The goal of this work is to expand this study on CaM using electron-capture dissociation (ECD) 2D MS as a single complementary BUP experiment in order to enhance the cleavage coverage of the protein under analysis. By adding the results of the BUP 2D ECD MS to the 2D IRMPD MS analysis of CaM, the total cleavage coverage increased from 40% to 68%. [Figure not available: see fulltext.

  11. Bottom-up fabrication of graphene on Ru(0001) via molecular self-assembly

    Science.gov (United States)

    Cai, Yiliang; Zhang, Hanjie; Song, Junjie; Zhang, Yuxi; Rehman, A. U.; He, Pimo

    2015-07-01

    A bottom-up fabrication of graphene via molecular self-assembly of p-Terphenyl on Ru(0001) has been investigated by scanning tunneling microcopy and density functional theory. Upon annealing of the sample at 450 °C, the intermediate stage is observed, in which the adsorbed p-Terphenyl molecules and graphitized flakes converted from the molecules coexist, implying the onset of dehydrogenation of p-Terphenyl. At the annealing temperature of 480 °C, the graphitized flakes start to convert into graphene. An adsoption energy of 5.99 eV is calculated for an individual p-Terphenyl molecule on Ru(0001), denoting a strong interaction between the adsorbate and substrate. The intermolecular interaction brings an extra adsorption energy of 0.28 eV for each molecule in the di-molecule adsorption system. During the conversion process from adsorbed molecule into graphene, the intermolecular interaction leads to the increase of the dehydrogenation barrier from 1.52 to 1.64 eV.

  12. Two Paths to Transforming Markets through Public Sector EnergyEfficiency: Bottom Up versus Top Down

    Energy Technology Data Exchange (ETDEWEB)

    Van Wie McGrory, Laura; Coleman, Philip; Fridley, David; Harris,Jeffrey; Villasenor Franco, Edgar

    2006-05-10

    The evolution of government purchasing initiatives in Mexicoand China, part of the PEPS (Promoting an Energy-efficient Public Sector)program, demonstrates the need for flexibility in designingenergy-efficiency strategies in the public sector. Several years ofpursuing a top-down (federally led) strategy in Mexico produced fewresults, and it was not until the program was restructured in 2004 tofocus on municipal-level purchasing that the program gained momentum.Today, a new partnership with the Mexican federal government is leadingto an intergovernmental initiative with strong support at the federallevel. By contrast, the PEPS purchasing initiative in China wassuccessfully initiated and led at the central government level withstrategic support from international experts. The very different successtrajectories in these two countries provide valuable lessons fordesigning country-specific public sector energy-efficiency initiatives.Enabling conditions for any successful public sector purchasinginitiative include the existence of mandatory energy-efficiencyperformance standards, an effective energy-efficiency endorsementlabeling program, an immediate need for energy conservation, a simplepilot phase (focusing on a limited number of strategically chosenproducts), and specialized technical assistance. Top-down purchasingprograms are likely to be more successful where there is high-levelpolitical endorsement and a national procurement law in place, supportedby a network of trained purchasers. Bottom-up (municipally led)purchasing programs require that municipalities have the authority to settheir own purchasing policies, and also benefit from existing networks ofcities, supported by motivated municipal leaders and trained purchasingofficials.

  13. Bottom-up synthesis of nitrogen-doped graphene sheets for ultrafast lithium storage.

    Science.gov (United States)

    Tian, Lei-Lei; Wei, Xian-Yong; Zhuang, Quan-Chao; Jiang, Chen-Hui; Wu, Chao; Ma, Guang-Yao; Zhao, Xing; Zong, Zhi-Min; Sun, Shi-Gang

    2014-06-07

    A facile bottom-up strategy was developed to fabricate nitrogen-doped graphene sheets (NGSs) from glucose using a sacrificial template synthesis method. Three main types of nitrogen dopants (pyridinic, pyrrolic and graphitic nitrogens) were introduced into the graphene lattice, and an inimitable microporous structure of NGS with a high specific surface area of 504 m(2) g(-1) was obtained. Particularly, with hybrid features of lithium ion batteries and Faradic capacitors at a low rate and features of Faradic capacitors at a high rate, the NGS presents a superior lithium storage performance. During electrochemical cycling, the NGS electrode afforded an enhanced reversible capacity of 832.4 mA h g(-1) at 100 mA g(-1) and an excellent cycling stability of 750.7 mA h g(-1) after 108 discharge-charge cycles. Furthermore, an astonishing rate capability of 333 mA h g(-1) at 10,000 mA g(-1) and a high rate cycle performance of 280.6 mA h g(-1) even after 1200 cycles were also achieved, highlighting the significance of nitrogen doping on the maximum utilization of graphene-based materials for advanced lithium storage.

  14. C-STrap Sample Preparation Method--In-Situ Cysteinyl Peptide Capture for Bottom-Up Proteomics Analysis in the STrap Format.

    Directory of Open Access Journals (Sweden)

    Alexandre Zougman

    Full Text Available Recently we introduced the concept of Suspension Trapping (STrap for bottom-up proteomics sample processing that is based upon SDS-mediated protein extraction, swift detergent removal and rapid reactor-type protein digestion in a quartz depth filter trap. As the depth filter surface is made of silica, it is readily modifiable with various functional groups using the silane coupling chemistries. Thus, during the digest, peptides possessing specific features could be targeted for enrichment by the functionalized depth filter material while non-targeted peptides could be collected as an unbound distinct fraction after the digest. In the example presented here the quartz depth filter surface is functionalized with the pyridyldithiol group therefore enabling reversible in-situ capture of the cysteine-containing peptides generated during the STrap-based digest. The described C-STrap method retains all advantages of the original STrap methodology and provides robust foundation for the conception of the targeted in-situ peptide fractionation in the STrap format for bottom-up proteomics. The presented data support the method's use in qualitative and semi-quantitative proteomics experiments.

  15. Dynamic Whitening Saliency.

    Science.gov (United States)

    Leboran, Victor; Garcia-Diaz, Anton; Fdez-Vidal, Xose R; Pardo, Xose M

    2017-05-01

    General dynamic scenes involve multiple rigid and flexible objects, with relative and common motion, camera induced or not. The complexity of the motion events together with their strong spatio-temporal correlations make the estimation of dynamic visual saliency a big computational challenge. In this work, we propose a computational model of saliency based on the assumption that perceptual relevant information is carried by high-order statistical structures. Through whitening, we completely remove the second-order information (correlations and variances) of the data, gaining access to the relevant information. The proposed approach is an analytically tractable and computationally simple framework which we call Dynamic Adaptive Whitening Saliency (AWS-D). For model assessment, the provided saliency maps were used to predict the fixations of human observers over six public video datasets, and also to reproduce the human behavior under certain psychophysical experiments (dynamic pop-out). The results demonstrate that AWS-D beats state-of-the-art dynamic saliency models, and suggest that the model might contain the basis to understand the key mechanisms of visual saliency. Experimental evaluation was performed using an extension to video of the well-known methodology for static images, together with a bootstrap permutation test (random label hypothesis) which yields additional information about temporal evolution of the metrics statistical significance.

  16. Importance of bottom-up approach in water management - sustainable development of catchment areas in Croatia

    Science.gov (United States)

    Pavic, M.; Cosic-Flajsig, G.; Petricec, M.; Blazevic, Z.

    2012-04-01

    Association for preservation of Croatian waters and sea SLAP is a non-governmental organization (NGO) that gathers more than 150 scientist, hydrologist and civil engineers. SLAP has been established in 2006 and since then had organized many conferences and participated in projects dealing with water management. We have started our work developing plans to secure water supply to the 22 (21) villages in the rural parts of Dubrovnik (Pozega) area and trough the years we have accumulated knowledge and experience in dealing with stakeholders in hydrology and water management. Within this paper we will present importance of bottom-up approach to the stakeholders in water management in Croatia on two case studies: (1) Management of River Trebizat catchment area - irrigation of the Imotsko-Bekijsko rural parts; (2) Development of multipurpose water reservoirs at the River Orljava catchment area. Both projects were designed in the mid and late 1980's but due to the war were forgotten and on halt. River Trebizat meanders between Croatia and Bosnia and Herzegovina and acquires joint management by both countries. In 2010 and 2011 SLAP has organized conferences in both countries gathering all the relevant stakeholders from representatives of local and state governments, water management companies and development agencies to the scientist and interested NGO's. The conferences gave firm scientific background of the topic including presentation of all previous studies and measurements as well as model results but presented in manner appropriate to the stakeholders. The main result of the conference was contribution to the development of joint cross-border project sent to the EU Pre-Accession funds in December 2011 with the aim to strengthen capacities of both countries and prepare larger project dealing with management of the whole Trebizat catchment area to EU structural funds once Croatia enters EU in 2013. Similar approach was taken for the Orljava catchment in the northern

  17. Bottom-up modeling approach for the quantitative estimation of parameters in pathogen-host interactions

    Directory of Open Access Journals (Sweden)

    Teresa eLehnert

    2015-06-01

    Full Text Available Opportunistic fungal pathogens can cause bloodstream infection and severe sepsis upon entering the blood stream of the host. The early immune response in human blood comprises the elimination of pathogens by antimicrobial peptides and innate immune cells, such as neutrophils or monocytes. Mathematical modeling is a predictive method to examine these complex processes and to quantify the dynamics of pathogen-host interactions. Since model parameters are often not directly accessible from experiment, their estimation is required by calibrating model predictions with experimental data. Depending on the complexity of the mathematical model, parameter estimation can be associated with excessively high computational costs in terms of run time and memory. We apply a strategy for reliable parameter estimation where different modeling approaches with increasing complexity are used that build on one another. This bottom-up modeling approach is applied to an experimental human whole-blood infection assay for Candida albicans. Aiming for the quantification of the relative impact of different routes of the immune response against this human-pathogenic fungus, we start from a non-spatial state-based model (SBM, because this level of model complexity allows estimating textit{a priori} unknown transition rates between various system states by the global optimization method simulated annealing. Building on the non-spatial SBM, an agent-based model (ABM is implemented that incorporates the migration of interacting cells in three-dimensional space. The ABM takes advantage of estimated parameters from the non-spatial SBM, leading to a decreased dimensionality of the parameter space. This space can be scanned using a local optimization approach, i.e. least-squares error estimation based on an adaptive regular grid search, to predict cell migration parameters that are not accessible in experiment.

  18. Bottom-up engineering of thermoelectric nanomaterials and devices from solution-processed nanoparticle building blocks.

    Science.gov (United States)

    Ortega, Silvia; Ibáñez, Maria; Liu, Yu; Zhang, Yu; Kovalenko, Maksym V; Cadavid, Doris; Cabot, Andreu

    2017-06-19

    The conversion of thermal energy to electricity and vice versa by means of solid state thermoelectric devices is extremely appealing. However, its cost-effectiveness is seriously hampered by the relatively high production cost and low efficiency of current thermoelectric materials and devices. To overcome present challenges and enable a successful deployment of thermoelectric systems in their wide application range, materials with significantly improved performance need to be developed. Nanostructuration can help in several ways to reach the very particular group of properties required to achieve high thermoelectric performances. Nanodomains inserted within a crystalline matrix can provide large charge carrier concentrations without strongly influencing their mobility, thus allowing to reach very high electrical conductivities. Nanostructured materials contain numerous grain boundaries that efficiently scatter mid- and long-wavelength phonons thus reducing the thermal conductivity. Furthermore, nanocrystalline domains can enhance the Seebeck coefficient by modifying the density of states and/or providing type- and energy-dependent charge carrier scattering. All these advantages can only be reached when engineering a complex type of material, nanocomposites, with exquisite control over structural and chemical parameters at multiple length scales. Since current conventional nanomaterial production technologies lack such level of control, alternative strategies need to be developed and adjusted to the specifics of the field. A particularly suitable approach to produce nanocomposites with unique level of control over their structural and compositional parameters is their bottom-up engineering from solution-processed nanoparticles. In this work, we review the state-of-the-art of this technology applied to the thermoelectric field, including the synthesis of nanoparticles of suitable materials with precisely engineered composition and surface chemistry, their combination

  19. Top-down or bottom-up: Contrasting perspectives on psychiatric diagnoses

    Directory of Open Access Journals (Sweden)

    Willem MA Verhoeven

    2008-09-01

    Full Text Available Willem MA Verhoeven1,2, Siegfried Tuinier1, Ineke van der Burgt31Vincent van Gogh Institute for Psychiatry, Venray, The Netherlands; 2Department of Psychiatry, Erasmus University Medical Centre, Rotterdam, The Netherlands; 3Department of Human Genetics, Radboud University Medical Centre, Nijmegen, The NetherlandsAbstract: Clinical psychiatry is confronted with the expanding knowledge of medical genetics. Most of the research into the genetic underpinnings of major mental disorders as described in the categorical taxonomies, however, did reveal linkage with a variety of chromosomes. This heterogeneity of results is most probably due to the assumption that the nosological categories as used in these studies are disease entities with clear boundaries. If the reverse way of looking, the so-called bottom-up approach, is applied, it becomes clear that genetic abnormalities are in most cases not associated with a single psychiatric disorder but with a certain probability to develop a variety of aspecific psychiatric symptoms. The adequacy of the categorical taxonomy, the so-called top-down approach, seems to be inversely related to the amount of empirical etiological data. This is illustrated by four rather prevalent genetic syndromes, fragile X syndrome, Prader-Willi syndrome, 22q11 deletion syndrome, and Noonan syndrome, as well as by some cases with rare chromosomal abnormalities. From these examples, it becomes clear that psychotic symptoms as well as mood, anxiety, and autistic features can be found in a great variety of different genetic syndromes. A psychiatric phenotype exists, but comprises, apart from the chance to present several psychiatric symptoms, all elements from developmental, neurocognitive, and physical characteristics.Keywords: genetic disorders, psychiatric symptoms, phenotype, mental disorders

  20. The case for refining bottom-up methane emission inventories using top-down measurements

    Science.gov (United States)

    Kelly, Bryce F. J.; Iverach, Charlotte P.; Ginty, Elisa; Bashir, Safdar; Lowry, Dave; Fisher, Rebecca E.; France, James L.; Nisbet, Euan G.

    2017-04-01

    Bottom-up global methane emission estimates are important for guiding policy development and mitigation strategies. Such inventories enable rapid and consistent proportioning of emissions by industrial sectors and land use at various scales from city to country to global. There has been limited use of top-down measurements to guide refining emission inventories. Here we compare the EDGAR gridmap data version 4.2 with over 5000 km of daytime ground level mobile atmospheric methane surveys in eastern Australia. The landscapes and industries surveyed include: urban environments, dryland farming, intensive livestock farming (both beef and lamb), irrigation agriculture, open cut and underground coal mining, and coal seam gas production. Daytime mobile methane surveys over a 2-year period show that at the landscape scale there is a high level of repeatability for the mole fraction of methane measured in the ground level atmosphere. Such consistency in the mole fraction of methane indicates that these data can be used as a proxy for flux. A scatter plot of the EDGAR emission gridmap Log[ton substance / 0.1 degree x 0.1 degree / year] versus the median mole fraction of methane / 0.1 degree x 0.1 degree in the ground level atmosphere highlights that the extent of elevated methane emissions associated with coal mining in the Hunter coalfields, which covers an area of 56 km by 24 km, has been under-represented in the EDGAR input data. Our results also show that methane emissions from country towns (population expansion of all forms of top-down emission estimates would result in reduced uncertainty in the global methane budget.

  1. Construction of mammographic examination process ontology using bottom-up hierarchical task analysis.

    Science.gov (United States)

    Yagahara, Ayako; Yokooka, Yuki; Jiang, Guoqian; Tsuji, Shintarou; Fukuda, Akihisa; Nishimoto, Naoki; Kurowarabi, Kunio; Ogasawara, Katsuhiko

    2018-01-10

    Describing complex mammography examination processes is important for improving the quality of mammograms. It is often difficult for experienced radiologic technologists to explain the process because their techniques depend on their experience and intuition. In our previous study, we analyzed the process using a new bottom-up hierarchical task analysis and identified key components of the process. Leveraging the results of the previous study, the purpose of this study was to construct a mammographic examination process ontology to formally describe the relationships between the process and image evaluation criteria to improve the quality of mammograms. First, we identified and created root classes: task, plan, and clinical image evaluation (CIE). Second, we described an "is-a" relation referring to the result of the previous study and the structure of the CIE. Third, the procedural steps in the ontology were described using the new properties: "isPerformedBefore," "isPerformedAfter," and "isPerformedAfterIfNecessary." Finally, the relationships between tasks and CIEs were described using the "isAffectedBy" property to represent the influence of the process on image quality. In total, there were 219 classes in the ontology. By introducing new properties related to the process flow, a sophisticated mammography examination process could be visualized. In relationships between tasks and CIEs, it became clear that the tasks affecting the evaluation criteria related to positioning were greater in number than those for image quality. We developed a mammographic examination process ontology that makes knowledge explicit for a comprehensive mammography process. Our research will support education and help promote knowledge sharing about mammography examination expertise.

  2. Bottom-up control of geomagnetic secular variation by the Earth's inner core.

    Science.gov (United States)

    Aubert, Julien; Finlay, Christopher C; Fournier, Alexandre

    2013-10-10

    Temporal changes in the Earth's magnetic field, known as geomagnetic secular variation, occur most prominently at low latitudes in the Atlantic hemisphere (that is, from -90 degrees east to 90 degrees east), whereas in the Pacific hemisphere there is comparatively little activity. This is a consequence of the geographical localization of intense, westward drifting, equatorial magnetic flux patches at the core surface. Despite successes in explaining the morphology of the geomagnetic field, numerical models of the geodynamo have so far failed to account systematically for this striking pattern of geomagnetic secular variation. Here we show that it can be reproduced provided that two mechanisms relying on the inner core are jointly considered. First, gravitational coupling aligns the inner core with the mantle, forcing the flow of liquid metal in the outer core into a giant, westward drifting, sheet-like gyre. The resulting shear concentrates azimuthal magnetic flux at low latitudes close to the core-mantle boundary, where it is expelled by core convection and subsequently transported westward. Second, differential inner-core growth, fastest below Indonesia, causes an asymmetric buoyancy release in the outer core which in turn distorts the gyre, forcing it to become eccentric, in agreement with recent core flow inversions. This bottom-up heterogeneous driving of core convection dominates top-down driving from mantle thermal heterogeneities, and localizes magnetic variations in a longitudinal sector centred beneath the Atlantic, where the eccentric gyre reaches the core surface. To match the observed pattern of geomagnetic secular variation, the solid material forming the inner core must now be in a state of differential growth rather than one of growth and melting induced by convective translation.

  3. Citizenship Policy from the Bottom-Up: The Linguistic and Semiotic Landscape of a Naturalization Field Office

    Science.gov (United States)

    Loring, Ariel

    2015-01-01

    This article follows a bottom-up approach to language policy (Ramanathan, 2005; Wodak, 2006) in an analysis of citizenship in policy and practice. It compares representations of citizenship in and around a regional branch of the United States Citizenship and Immigration Services (USCIS), with a focus on citizenship swearing-in ceremonies for…

  4. Enhancing criterion-related validity through bottom-up contextualization of personality inventories: The construction of an ecological conscientiousness scale

    NARCIS (Netherlands)

    Marise Born; dr René Butter

    2011-01-01

    In this paper the concept of "ecological personality scales" is introduced. These are contextualized inventories with a high ecological validity. They are developed in a bottom-up or qualitative way and combine a relatively high trait specificity with a relatively high situational specificity. An

  5. Leadership for Quality University Teaching: How Bottom-Up Academic Insights Can Inform Top-Down Leadership

    Science.gov (United States)

    Scott, Donald E.; Scott, Shelleyann

    2016-01-01

    This paper presents the leadership implications from a study that explored how to increase the quality of teaching in a university thereby presenting data from the bottom up--the academic perspective--to inform leadership, policies, and academic development which generally flows from the top down. We report academics' perceptions of and…

  6. Balancing Top-Down, Bottom-Up, and Peer-to-Peer Approaches to Sustaining Distance Training

    Science.gov (United States)

    Dudink, Gertrude; Berge, Zane

    2006-01-01

    Many distance training case studies identify distance training leadership as bottom-up, whereas much of the literature suggests a need for strategic, top-down approaches. With change management as an overarching framework, approaches to sustaining distance training that originate at different levels of the organization are explored. Special…

  7. An integrative top-down and bottom-up qualitative model construction framework for exploration of biochemical systems.

    Science.gov (United States)

    Wu, Zujian; Pang, Wei; Coghill, George M

    Computational modelling of biochemical systems based on top-down and bottom-up approaches has been well studied over the last decade. In this research, after illustrating how to generate atomic components by a set of given reactants and two user pre-defined component patterns, we propose an integrative top-down and bottom-up modelling approach for stepwise qualitative exploration of interactions among reactants in biochemical systems. Evolution strategy is applied to the top-down modelling approach to compose models, and simulated annealing is employed in the bottom-up modelling approach to explore potential interactions based on models constructed from the top-down modelling process. Both the top-down and bottom-up approaches support stepwise modular addition or subtraction for the model evolution. Experimental results indicate that our modelling approach is feasible to learn the relationships among biochemical reactants qualitatively. In addition, hidden reactants of the target biochemical system can be obtained by generating complex reactants in corresponding composed models. Moreover, qualitatively learned models with inferred reactants and alternative topologies can be used for further web-lab experimental investigations by biologists of interest, which may result in a better understanding of the system.

  8. Two-dimensional combinatorial screening enables the bottom-up design of a microRNA-10b inhibitor.

    Science.gov (United States)

    Velagapudi, Sai Pradeep; Disney, Matthew D

    2014-03-21

    The RNA motifs that bind guanidinylated kanamycin A (G Kan A) and guanidinylated neomycin B (G Neo B) were identified via two-dimensional combinatorial screening (2DCS). The results of these studies enabled the "bottom-up" design of a small molecule inhibitor of oncogenic microRNA-10b.

  9. A critical role of temporoparietal junction in the integration of top-down and bottom-up attentional control.

    Science.gov (United States)

    Wu, Qiong; Chang, Chi-Fu; Xi, Sisi; Huang, I-Wen; Liu, Zuxiang; Juan, Chi-Hung; Wu, Yanhong; Fan, Jin

    2015-11-01

    Information processing can be biased toward behaviorally relevant and salient stimuli by top-down (goal-directed) and bottom-up (stimulus-driven) attentional control processes respectively. However, the neural basis underlying the integration of these processes is not well understood. We employed functional magnetic resonance imaging (fMRI) and transcranial direct-current stimulation (tDCS) in humans to examine the brain mechanisms underlying the interaction between these two processes. We manipulated the cognitive load involved in top-down processing and stimulus surprise involved in bottom-up processing in a factorial design by combining a majority function task and an oddball paradigm. We found that high cognitive load and high surprise level were associated with prolonged reaction time compared to low cognitive load and low surprise level, with a synergistic interaction effect, which was accompanied by a greater deactivation of bilateral temporoparietal junction (TPJ). In addition, the TPJ displayed negative functional connectivity with right middle occipital gyrus, which is involved in bottom-up processing (modulated by the interaction effect), and the right frontal eye field (FEF), which is involved in top-down control. The enhanced negative functional connectivity between the TPJ and right FEF was accompanied by a larger behavioral interaction effect across subjects. Application of cathodal tDCS over the right TPJ eliminated the interaction effect. These results suggest that the TPJ plays a critical role in processing bottom-up information for top-down control of attention. © 2015 Wiley Periodicals, Inc.

  10. Improving Reading Fluency and Comprehension in Adult ESL Learners Using Bottom-Up and Top-Down Vocabulary Training

    Science.gov (United States)

    Oliver, Rhonda; Young, Shahreen

    2016-01-01

    The current research examines the effect of two methods of vocabulary training on reading fluency and comprehension of adult English as second language (ESL) tertiary-bound students. The methods used were isolated vocabulary training (bottom-up reading) and vocabulary training in context (top-down reading). The current exploratory and…

  11. A comparative study of benchmarking approaches for non-domestic buildings: Part 2 – Bottom-up approach

    Directory of Open Access Journals (Sweden)

    Esfandiar Burman

    2014-12-01

    Full Text Available The bottom-up methods for energy benchmarking aim to derive a yardstick for energy performance based on a theoretical analysis of a building. While the top-down methods drive performance improvement by ranking a building against its peers, the bottom-up methods are focused on the building’s specific context. Consequently, the bottom-up methods can help identify how performance improvement could be materialised. These two complementary approaches can improve design practice and facilities’ management. Two bottom-up methods that could be used for energy benchmarking have been reviewed using UK schools as case studies: Building physics and aggregated end-use. The aim is to demonstrate how these methods could be used for benchmarking and identify their benefits and limitations. When all energy components are included in a model under expected operating conditions, the building physics method can be used to establish a baseline for energy performance. It is demonstrated that where this method is used under standardised operating conditions and is subject to minimum energy performance requirements, as prescribed by the Energy Performance of Buildings Directive (EPBD, it can be used to establish a benchmark for energy performance. It is also shown how aggregated end-use methods such as CIBSE TM22 can be used to define system level benchmarks, and identify the root causes for discrepancy between measured performance and design intent in a systematic way.

  12. Using classic methods in a networked manner: seeing volunteered spatial information in a bottom-up fashion

    NARCIS (Netherlands)

    Carton, L.J.; Ache, P.M.

    2014-01-01

    Using new social media and ICT infrastructures for self-organization, more and more citizen networks and business sectors organize themselves voluntarily around sustainability themes. The paper traces and evaluates one emerging innovation in such bottom-up, networked form of sustainable

  13. Second Language Listening Instruction: Comparing a Strategies-Based Approach with an Interactive, Strategies/Bottom-Up Skills Approach

    Science.gov (United States)

    Yeldham, Michael

    2016-01-01

    This quasi-experimental study compared a strategies approach to second language listening instruction with an interactive approach, one combining a roughly equal balance of strategies and bottom-up skills. The participants were lower-intermediate-level Taiwanese university EFL learners, who were taught for 22 hours over one and a half semesters.…

  14. Evaluating the Resilience of the Bottom-up Method used to Detect and Benchmark the Smartness of University Campuses

    NARCIS (Netherlands)

    Giovannella, Carlo; Andone, Diana; Dascalu, Mihai; Popescu, Elvira; Rehm, Matthias; Mealha, Oscar

    2017-01-01

    A new method to perform a bottom-up extraction and benchmark of the perceived multilevel smartness of complex ecosystems has been recently described and applied to territories and learning ecosystems like university campuses and schools. In this paper we study the resilience of our method

  15. The landscape of fear: The missing link to understand top-down and bottom-up controls of prey abundance?

    Science.gov (United States)

    Identifying factors that may be responsible for affecting and possibly regulating the size of animal populations is a cornerstone in understanding population ecology. The main factors that are thought to influence population size are either resources (bottom-up), predation, (top-down), or interspec...

  16. Bottom-Up Design of a Copper-Ruthenium Nanoparticulate Catalyst for Low-Temperature Ammonia Oxidation

    DEFF Research Database (Denmark)

    Chakraborty, Debasish; Damsgaard, Christian Danvad; Silva, Hugo José Lopes

    2017-01-01

    A novel nanoparticulate catalyst of copper (Cu) and ruthenium (Ru) was designed for low-temperature ammonia oxidation at near-stoichiometric mixtures using a bottom-up approach. A synergistic effect of the two metals was found. An optimum CuRu catalyst presents a reaction rate threefold higher than...

  17. Cyclization of the N-Terminal X-Asn-Gly Motif during Sample Preparation for Bottom-Up Proteomics

    DEFF Research Database (Denmark)

    Zhang, Xumin; Højrup, Peter

    2010-01-01

    We, herein, report a novel -17 Da peptide modification corresponding to an N-terminal cyclization of peptides possessing the N-terminal motif of X-Asn-Gly. The cyclization occurs spontaneously during sample preparation for bottom-up proteomics studies. Distinct from the two well-known N...

  18. The Comparative Effect of Top-down Processing and Bottom-up Processing through TBLT on Extrovert and Introvert EFL

    Directory of Open Access Journals (Sweden)

    Pezhman Nourzad Haradasht

    2013-09-01

    Full Text Available This research seeks to examine the effect of two models of reading comprehension, namely top-down and bottom-up processing, on the reading comprehension of extrovert and introvert EFL learners’ reading comprehension. To do this, 120 learners out of a total number of 170 intermediate learners being educated at Iran Mehr English Language School were selected all taking a PET (Preliminary English Test first for homogenization prior to the study. They also answered the Eysenck Personality Inventory (EPI which in turn categorized them into two subgroups within each reading models consisting of introverts and extroverts. All in all, there were four subgroups: 30 introverts and 30 extroverts undergoing the top-down processing treatment, and 30 introverts and 30 extroverts experiencing the bottom-up processing treatment. The aforementioned PET was administered as the post test of the study after each group was exposed to the treatment for 18 sessions in six weeks. After the instructions finished, the mean scores of all four groups on this post test were computed and a two-way ANOVA was run to test all the four hypotheses raise in this study. the results showed that while learners generally benefitted more from the bottom-up processing setting compared  to the top-down processing one, the extrovert group was better off receiving top-down instruction. Furthermore, introverts outperformed extroverts in bottom-up group; yet between the two personalities subgroups in the top-down setting no difference was seen. A predictable pattern of benefitting from teaching procedures could not be drawn for introverts as in both top-down and bottom-up settings, they benefitted more than extroverts.

  19. Reconciling Top-Down and Bottom-Up Estimates of Oil and Gas Methane Emissions in the Barnett Shale

    Science.gov (United States)

    Hamburg, S.

    2015-12-01

    Top-down approaches that use aircraft, tower, or satellite-based measurements of well-mixed air to quantify regional methane emissions have typically estimated higher emissions from the natural gas supply chain when compared to bottom-up inventories. A coordinated research campaign in October 2013 used simultaneous top-down and bottom-up approaches to quantify total and fossil methane emissions in the Barnett Shale region of Texas. Research teams have published individual results including aircraft mass-balance estimates of regional emissions and a bottom-up, 25-county region spatially-resolved inventory. This work synthesizes data from the campaign to directly compare top-down and bottom-up estimates. A new analytical approach uses statistical estimators to integrate facility emission rate distributions from unbiased and targeted high emission site datasets, which more rigorously incorporates the fat-tail of skewed distributions to estimate regional emissions of well pads, compressor stations, and processing plants. The updated spatially-resolved inventory was used to estimate total and fossil methane emissions from spatial domains that match seven individual aircraft mass balance flights. Source apportionment of top-down emissions between fossil and biogenic methane was corroborated with two independent analyses of methane and ethane ratios. Reconciling top-down and bottom-up estimates of fossil methane emissions leads to more accurate assessment of natural gas supply chain emission rates and the relative contribution of high emission sites. These results increase our confidence in our understanding of the climate impacts of natural gas relative to more carbon-intensive fossil fuels and the potential effectiveness of mitigation strategies.

  20. A bottom-up approach to urban metabolism: the perspective of BRIDGE

    Science.gov (United States)

    Chrysoulakis, N.; Borrego, C.; San Josè, R.; Grimmond, S. B.; Jones, M. B.; Magliulo, V.; Klostermann, J.; Santamouris, M.

    2011-12-01

    Urban metabolism considers a city as a system and usually distinguishes between energy and material flows as its components. "Metabolic" studies are usually top-down approaches that assess the inputs and outputs of food, water, energy, and pollutants from a city, or that compare the changing metabolic process of several cities. In contrast, bottom-up approaches are based on quantitative estimates of urban metabolism components at local to regional scales. Such approaches consider the urban metabolism as the 3D exchange and transformation of energy and matter between a city and its environment. The city is considered as a system and the physical flows between this system and its environment are quantitatively estimated. The transformation of landscapes from primarily agricultural and forest uses to urbanized landscapes can greatly modify energy and material exchanges and it is, therefore, an important aspect of an urban area. Here we focus on the exchanges and transformation of energy, water, carbon and pollutants. Recent advances in bio-physical sciences have led to new methods and models to estimate local scale energy, water, carbon and pollutant fluxes. However, there is often poor communication of new knowledge and its implications to end-users, such as planners, architects and engineers. The FP7 Project BRIDGE (SustainaBle uRban plannIng Decision support accountinG for urban mEtabolism) aims at bridging this gap and at illustrating the advantages of considering environmental issues in urban planning. BRIDGE does not perform a complete life cycle analysis or calculate whole system urban metabolism, but rather focuses on specific metabolism components (energy, water, carbon and pollutants). Its main goal is the development of a Decision Suport System (DSS) with the potential to select planning actions which better fit the goal of changing the metabolism of urban systems towards sustainability. BRIDGE evaluates how planning alternatives can modify the physical

  1. Air pollution in Latin America: Bottom-up Vehicular Emissions Inventory and Atmospheric Modeling

    Science.gov (United States)

    Ibarra Espinosa, S.; Vela, A. V.; Calderon, M. G.; Carlos, G.; Ynoue, R.

    2016-12-01

    Air pollution is a global environmental and health problem. Population of Latin America are facing air quality risks due to high level of air pollution. According to World Health Organization (WHO; 2016), several Latin American cities have high level of pollution. Emissions inventories are a key tool for air quality, however they normally present lack of quality and adequate documentation in developing countries. This work aims to develop air quality assessments in Latin American countries by 1) develop a high resolution emissions inventory of vehicles, and 2) simulate air pollutant concentrations. The bottom-up vehicular emissions inventory used was obtained with the REMI model (Ibarra et al., 2016) which allows to interpolate traffic over road network of Open Street Map to estimate vehicular emissions 24-h, each day of the week. REMI considers several parameters, among them the average age of fleet which was associated with gross domestic product (GDP) per capita. The estimated pollutants are CO, NOx, HC, PM2.5, NO, NO2, CO2, N2O, COV, NH3 and Fuel Consumption. The emissions inventory was performed at the biggest cities, including every capital of Latin America's countries. Initial results shows that the cities with most CO emissions are Buenos Aires 162800 (t/year), São Paulo 152061 (t/year), Campinas 151567 (t/year) and Brasilia 144332 (t/year). The results per capita shows that the city with most CO emissions per capita is Campinas, with 130 (kgCO/hab/year), showed in figure 1. This study also cover high resolution air quality simulations with WRF-Chem main cities in Latin America. Results will be assessed comparing: fuel estimates with local fuel sales, traffic count interpolation with available traffic data set at each city, and comparison between air pollutant simulations with air monitoring observation data. Ibarra, S., R. Ynoue, and S. Mhartain. 2016: "High Resolution Vehicular Emissions Inventory for the Megacity of São Paulo." Manuscript submitted to

  2. The role of attentional priority and saliency in determining capacity limits in enumeration and visual working memory.

    Directory of Open Access Journals (Sweden)

    David Melcher

    Full Text Available Many common tasks require us to individuate in parallel two or more objects out of a complex scene. Although the mechanisms underlying our abilities to count the number of items, remember the visual properties of objects and to make saccadic eye movements towards targets have been studied separately, each of these tasks require selection of individual objects and shows a capacity limit. Here we show that a common factor--salience--determines the capacity limit in the various tasks. We manipulated bottom-up salience (visual contrast and top-down salience (task relevance in enumeration and visual memory tasks. As one item became increasingly salient, the subitizing range was reduced and memory performance for all other less-salient items was decreased. Overall, the pattern of results suggests that our abilities to enumerate and remember small groups of stimuli are grounded in an attentional priority or salience map which represents the location of important items.

  3. Merging bottom-up and top-down precipitation products using a stochastic error model

    Science.gov (United States)

    Maggioni, Viviana; Massari, Christian; Brocca, Luca; Ciabatta, Luca

    2017-04-01

    Accurate quantitative precipitation estimation is of great importance for water resources management, agricultural planning, and forecasting and monitoring of natural hazards such as flash floods and landslides. In situ observations are limited around the Earth, especially in remote areas (e.g., complex terrain, dense vegetation), but currently available satellite precipitation products are able to provide global precipitation estimates with an accuracy that depends upon many factors (e.g., type of storms, temporal sampling, season etc…). Recently, Brocca et al. (2014) have proposed an alternative approach (i.e., SM2RAIN) that allows to estimate rainfall from space by using satellite soil moisture observations. In contrast with classical satellite precipitation products which sense the cloud properties to retrieve the instantaneous precipitation, this new bottom-up approach makes use of two consecutive soil moisture measurements for obtaining an estimate of the fallen precipitation within the interval between two satellite passes. As a result, the nature of the measurement is different and complementary to the one of classical precipitation products and could provide a different valid perspective to improve current satellite rainfall estimates via appropriate integration between the products (i.e., SM2RAIN plus a classical satellite rainfall product). However, whether SM2RAIN is able or not to improve the performance of any state-of-the-art satellite rainfall product is much dependent upon an adequate quantification and characterization of the relative errors of the products. In this study, the stochastic rainfall error model SREM2D (Hossain et al. 2006) is used for characterizing the retrieval error of both SM2RAIN and a state-of-the-art satellite precipitation product (i.e., 3B42RT). The error characterization serves for an optimal integration between SM2RAIN and 3B42RT for enhancing the capability of the resulting integrated product (i.e. SM2RAIN+3B42RT) in

  4. Label-Free Bottom-Up Proteomic Workflow for Simultaneously Assessing the Target Specificity of Covalent Drug Candidates and Their Off-Target Reactivity to Selected Proteins.

    Science.gov (United States)

    Yang, Yanou; Shu, Yue-Zhong; Humphreys, W Griffith

    2016-01-19

    Although designed covalent inhibitors as drug candidates offer several unique advantages over conventional reversible inhibitors, including high potency and the potential for less frequent dosing, there is a general tendency to avoid the covalent mode of action in drug discovery programs due to concerns regarding immune-mediated toxicity that can arise from indiscriminate reactivity with off-target proteins. Therefore, the ability to assess off-target reactivity relative to target specificity is desirable for optimizing covalent drug candidates in the early discovery stage. One concern with current surrogate nucleophile trapping approaches is that they employ a simplistic model nucleophile such as glutathione, which may not reliably reflect the covalent interactions with cellular or extracellular proteins. One way to get a more relevant reactivity assessment is to directly measure the ability of an inhibitor to covalently modify nucelophilic amino acids on biologically relevant proteins, both on- and off-target. In this article, we describe a label-free bottom-up proteomic workflow for simultaneous evaluation of target binding and off-target reactivity of covalent drug candidates to selected proteins at the peptide level. Ibrutinib, a covalent drug targeting the active site of BTK protein, was used as a model compound to demonstrate the feasibility of the workflow. The compound was incubated with a mixture of target protein, Bruton's tyrosine kinase (BTK), and two abundant proteins in blood, hemoglobin (Hb) and human serum albumin (HSA), and then the ibrutinib modification sites were determined utilizing a bottom-up proteomic approach. A non-BTK specific model compound (1) known to modify cysteine residues was also included. By comparing the extent of off-target modifications to the targeted BTK C481 binding in a wide compound concentration range, we were able to determine the concentration where maximum target binding was achieved with minimal off

  5. Improving reading fluency and comprehension in adult ESL learners using bottom-up and top-down vocabulary training

    Directory of Open Access Journals (Sweden)

    Rhonda Oliver

    2016-03-01

    Full Text Available The current research examines the effect of two methods of vocabulary training on reading fluency and comprehension of adult English as second language (ESL tertiary-bound students. The methods used were isolated vocabulary training (bottom-up reading and vocabulary training in context (top-down reading. The current exploratory and quasi-experimental study examines the effectiveness of these methods in two intact classes using pre- and posttest measures of students’ reading fluency and comprehension. The results show that bottom-up training had a negative impact on fluency and comprehension. In contrast, top-down training positively affected fluency but had no impact on comprehension. Further, the results do suggest that fast-paced reading may potentially lead to improved comprehension. These findings have implications for the type of language instruction used in classrooms and, therefore, for teachers of adult ESL learners.

  6. Binaural beat salience

    Science.gov (United States)

    Grose, John H.; Buss, Emily; Hall, Joseph W.

    2012-01-01

    Previous studies of binaural beats have noted individual variability and response lability, but little attention has been paid to the salience of the binaural beat percept. The purpose of this study was to gauge the strength of the binaural beat percept by matching its salience to that of sinusoidal amplitude modulation (SAM), and to then compare rate discrimination for the two types of fluctuation. Rate discrimination was measured for standard rates of 4, 8, 16, and 32 Hz – all in the 500-Hz carrier region. Twelve normal-hearing adults participated in this study. The results indicated that discrimination acuity for binaural beats is similar to that for SAM tones whose depths of modulation have been adjusted to provide equivalent modulation salience. The matched-salience SAM tones had relatively shallow depths of modulation, suggesting that the perceptual strength of binaural beats is relatively weak, although all listeners perceived them. The Weber fraction for detection of an increase in binaural beat rate is roughly constant across beat rates, at least for rates above 4 Hz, as is rate discrimination for SAM tones. PMID:22326292

  7. Balancing Top-Down, Bottom-Up, and Peer-to-Peer Approaches to Sustaining Distance Training

    OpenAIRE

    DUDINK, Gertrude; BERGE, Zane

    2015-01-01

    Many distance training case studies identify distance training leadership as bottom-up, whereas much of the literature suggests a need for strategic, top-down approaches. With change management as an overarching framework, approaches to sustaining distance training that originate at different levels of the organization are explored. Special attention is paid to the content of the change messages involved, guided by Rogers’ five attributes of innovations. Research of change management and dist...

  8. Developing a comprehensive and comparative questionnaire for measuring personality in chimpanzees using a simultaneous top-down/bottom-up design.

    Science.gov (United States)

    Freeman, Hani D; Brosnan, Sarah F; Hopper, Lydia M; Lambeth, Susan P; Schapiro, Steven J; Gosling, Samuel D

    2013-10-01

    One effective method for measuring personality in primates is to use personality trait ratings to distill the experience of people familiar with the individual animals. Previous rating instruments were created using either top-down or bottom-up approaches. Top-down approaches, which essentially adapt instruments originally designed for use with another species, can unfortunately lead to the inclusion of traits irrelevant to chimpanzees or fail to include all relevant aspects of chimpanzee personality. Conversely, because bottom-up approaches derive traits specifically for chimpanzees, their unique items may impede comparisons with findings in other studies and other species. To address the limitations of each approach, we developed a new personality rating scale using a combined top-down/bottom-up design. Seventeen raters rated 99 chimpanzees on the new 41-item scale, with all but one item being rated reliably. Principal components analysis, using both varimax and direct oblimin rotations, identified six broad factors. Strong evidence was found for five of the factors (Reactivity/Undependability, Dominance, Openness, Extraversion, and Agreeableness). A sixth factor (Methodical) was offered provisionally until more data are collected. We validated the factors against behavioral data collected independently on the chimpanzees. The five factors demonstrated good evidence for convergent and predictive validity, thereby underscoring the robustness of the factors. Our combined top-down/bottom-up approach provides the most extensive data to date to support the universal existence of these five personality factors in chimpanzees. This framework, which facilitates cross-species comparisons, can also play a vital role in understanding the evolution of personality and can assist with husbandry and welfare efforts. © 2013 Wiley Periodicals, Inc.

  9. Analyzing ENUM Service and Administration from the Bottom Up: The addressing system for IP telephony and beyond

    OpenAIRE

    Hwang, Junseok; Mueller, Milton; Yoon, Gunyoung; Kim, Joonmin

    2001-01-01

    ENUM creates many new market opportunities and raises several important policy issues related to the implementation and administration of the ENUM database and services. Recent World Telecommunications Policy Forum 2001 dealt with the emergence of ENUM as an important numbering issue of IP telephony. This paper prepares some important emerging issues of ENUM administration and policy by taking an empirical research approach from the bottom up. We will identify potential key ENUM services, and...

  10. The Comparative Effect of Top-down Processing and Bottom-up Processing through TBLT on Extrovert and Introvert EFL

    OpenAIRE

    Pezhman Nourzad Haradasht; Abdollah Baradaran

    2013-01-01

    This research seeks to examine the effect of two models of reading comprehension, namely top-down and bottom-up processing, on the reading comprehension of extrovert and introvert EFL learners’ reading comprehension. To do this, 120 learners out of a total number of 170 intermediate learners being educated at Iran Mehr English Language School were selected all taking a PET (Preliminary English Test) first for homogenization prior to the study. They also answered the Eysenck Personality Invent...

  11. Top-down and bottom-up influences on demographic rates of Antarctic fur seals Arctocephalus gazella.

    Science.gov (United States)

    Schwarz, Lisa K; Goebel, Michael E; Costa, Daniel P; Kilpatrick, A Marm

    2013-07-01

    Two major drivers in population dynamics are bottom-up processes, such as environmental factors that affect foraging success, and the top-down impacts of predation. Many populations of marine mammal and seabird species appear to be declining in response to reductions in prey associated with the bottom-up effects of climate change. However, predation, which usually occurs at sea and is difficult to observe, may also play a key role. We analysed drivers of population dynamics of Antarctic fur seals Arctocephalus gazella at Cape Shirreff from 1997 to 2009, including a predator that targets pre-weaned pups and bottom-up environmental effects in an ecosystem particularly sensitive to small changes in temperature. We use Bayesian mark-recapture analysis to demonstrate that although large-scale environmental variability affects annual adult survival and reproduction, first year survival appears to be driving the current decline in this population (as defined by a decline in the annual number of pups born). Although the number of pups increased during the first third of the study, first year survival and recruitment of those pups in later years was very low. Such low survival may be driven by leopard seal Hydrurga leptonyx predation, particularly prior to weaning. Our results suggest that without leopard seal predation, this population would most likely increase in size, despite the observed bottom-up effects of climate changes on adult vital rates. More broadly, our results show how age-targeted predation could be a major factor in population decline of K-selected colonial breeders. © 2013 The Authors. Journal of Animal Ecology © 2013 British Ecological Society.

  12. Incentives for Collaborative Governance: Top-Down and Bottom-Up Initiatives in the Swedish Mountain Region

    Directory of Open Access Journals (Sweden)

    Katarina Eckerberg

    2015-08-01

    Full Text Available Governance collaborations between public and private partners are increasingly used to promote sustainable mountain development, yet information is limited on their nature and precise extent. This article analyzes collaboration on environment and natural resource management in Swedish mountain communities to critically assess the kinds of issues these efforts address, how they evolve, who leads them, and what functional patterns they exhibit based on Margerum's (2008 typology of action, organizational, and policy collaboration. Based on official documents, interviews, and the records of 245 collaborative projects, we explore the role of the state, how perceptions of policy failure may inspire collaboration, and the opportunities that European Union funds have created. Bottom-up collaborations, most of which are relatively recent, usually have an action and sometimes an organizational function. Top-down collaborations, however, are usually organizational or policy oriented. Our findings suggest that top-down and bottom-up collaborations are complementary in situations with considerable conflict over time and where public policies have partly failed, such as for nature protection and reindeer grazing. In less contested areas, such as rural development, improving tracks and access, recreation, and fishing, there is more bottom-up, action-oriented collaboration. State support, especially in the form of funding, is central to explaining the emergence of bottom-up action collaboration. Our findings show that the state both initiates and coordinates policy networks and retains a great deal of power over the nature and functioning of collaborative governance. A practical consequence is that there is great overlap—aggravated by sectorized approaches—that creates a heavy workload for some regional partners.

  13. Improving reading fluency and comprehension in adult ESL learners using bottom-up and top-down vocabulary training

    OpenAIRE

    Rhonda Oliver; Shahreen Young

    2016-01-01

    The current research examines the effect of two methods of vocabulary training on reading fluency and comprehension of adult English as second language (ESL) tertiary-bound students. The methods used were isolated vocabulary training (bottom-up reading) and vocabulary training in context (top-down reading). The current exploratory and quasi-experimental study examines the effectiveness of these methods in two intact classes using pre- and posttest measures of students’ reading fluency and com...

  14. Enhanced protein identification using graphite-modified MALDI plates for offline LC-MALDI-MS/MS bottom-up proteomics.

    Science.gov (United States)

    Maus, Anthony; Mignon, Rudolph; Basile, Franco

    2018-01-08

    The use of offline liquid chromatography-matrix assisted laser desorption/ionization (LC-MALDI) tandem mass spectrometry (MS/MS) for bottom-up proteomics offers advantages in terms of cost, ease of use, and the time-decoupled nature of the separation step and the mass analysis. A method was developed to improve the capabilities of LC-MALDI-MS/MS in terms of protein identification in a bottom-up proteomic workflow. Enhanced protein identification is achieved by an increase in the MALDI signal intensity of the precursor peptides brought about by coating the MALDI plate with a thin film of graphite powder. Using the Escherichia coli proteome, it is demonstrated that the graphite-modified MALDI plates used in an offline LC-MALDI-MS/MS bottom-up protocol led to a 50-135% increase in the number of peptide identifications, and a concomitant 21%-105% increase in the number of proteins inferred. We identify factors that lead to improvements in peptide sequence identifications and in the number of unique proteins identified when compared to using an unmodified MALDI plate. These improvements are achieved using a low cost approach that it is easy to implement, requires no hardware/protocol modification, it is compatible with LC and adds no additional analysis time. Copyright © 2018 Elsevier Inc. All rights reserved.

  15. Sponge communities on Caribbean coral reefs are structured by factors that are top-down, not bottom-up.

    Directory of Open Access Journals (Sweden)

    Joseph R Pawlik

    Full Text Available Caribbean coral reefs have been transformed in the past few decades with the demise of reef-building corals, and sponges are now the dominant habitat-forming organisms on most reefs. Competing hypotheses propose that sponge communities are controlled primarily by predatory fishes (top-down or by the availability of picoplankton to suspension-feeding sponges (bottom-up. We tested these hypotheses on Conch Reef, off Key Largo, Florida, by placing sponges inside and outside predator-excluding cages at sites with less and more planktonic food availability (15 m vs. 30 m depth. There was no evidence of a bottom-up effect on the growth of any of 5 sponge species, and 2 of 5 species grew more when caged at the shallow site with lower food abundance. There was, however, a strong effect of predation by fishes on sponge species that lacked chemical defenses. Sponges with chemical defenses grew slower than undefended species, demonstrating a resource trade-off between growth and the production of secondary metabolites. Surveys of the benthic community on Conch Reef similarly did not support a bottom-up effect, with higher sponge cover at the shallower depth. We conclude that the structure of sponge communities on Caribbean coral reefs is primarily top-down, and predict that removal of sponge predators by overfishing will shift communities toward faster-growing, undefended species that better compete for space with threatened reef-building corals.

  16. Does Plant Cultivar Difference Modify the Bottom-Up Effects of Resource Limitation on Plant-Insect Herbivore Interactions?

    Science.gov (United States)

    Han, Peng; Desneux, Nicolas; Michel, Thomas; Le Bot, Jacques; Seassau, Aurelie; Wajnberg, Eric; Amiens-Desneux, Edwige; Lavoir, Anne-Violette

    2016-12-01

    Variation in resource input to plants triggers bottom-up effects on plant-insect herbivore interactions. However, variation in plant intrinsic traits in response to resource availability may modify the bottom-up effects. Furthermore, the consequences also may depend on the feeding strategy of insect herbivores belonging to different feeding guilds. We evaluated the performance of two insect herbivores from distinct feeding guilds, the leaf miner Tuta absoluta and the phloem feeder Bemisia tabaci. We offered the insects two tomato cultivars growing under optimal nitrogen input vs. nitrogen limitation, or under optimal water input vs. water limitation. We found that: (i) the two cultivars differed in their responses to nitrogen and water limitation by regulating primary (leaf-gas exchange related parameters, leaf nitrogen content, and leaf C/N ratio) and secondary metabolism (main defensive compounds: glycoalkaloids); (ii) for both plant cultivars, nitrogen or water limitation significantly affected T. absoluta survival and development, while B. tabaci survival was affected only by nitrogen limitation; and surprisingly (iii) plant cultivar differences did not modify the negative bottom-up effects of resource limitation on the two insect herbivores. In conclusion, the negative effects of resource limitation cascaded up to insect herbivores even though plant cultivars exhibited various adaptive traits to resource limitation.

  17. Dissociating Bottom-Up and Top-Down Mechanisms in the Cortico-Limbic System during Emotion Processing.

    Science.gov (United States)

    Comte, Magali; Schön, Daniele; Coull, Jennifer T; Reynaud, Emmanuelle; Khalfa, Stéphanie; Belzeaux, Raoul; Ibrahim, El Chérif; Guedj, Eric; Blin, Olivier; Weinberger, Daniel R; Fakra, Eric

    2016-01-01

    The cortico-limbic system is critically involved in emotional responses and resulting adaptive behaviors. Within this circuit, complementary regions are believed to be involved in either the appraisal or the regulation of affective state. However, the respective contribution of these bottom-up and top-down mechanisms during emotion processing remains to be clarified. We used a new functional magnetic resonance imaging (fMRI) paradigm varying 3 parameters: emotional valence, emotional congruency, and allocation of attention, to distinguish the functional variation in activity and connectivity between amygdala, anterior cingulate cortex (ACC), and dorsolateral prefrontal cortex (DLPFC). Bottom-up appraisal of negative compared with positive stimuli led to a greater amygdala response and stronger functional interaction between amygdala and both dorsal ACC and DLPFC. Top-down resolution of emotional conflict was associated with increased activity within ACC and higher functional connectivity between this structure, and both the amygdala and DLPFC. Finally, increased top-down attentional control caused greater engagement of the DLPFC, accompanied by increased connectivity between DLPFC and dorsal ACC. This novel task provides an efficient tool for exploring bottom-up and top-down processes underlying emotion and may be particularly helpful for investigating the neurofunctional underpinnings of psychiatric disorders. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  18. Top-down and bottom-up control of large herbivore populations: a review of natural and human-induced influences

    NARCIS (Netherlands)

    Gandiwa, E.

    2013-01-01

    The question whether animal populations are top-down and/or bottom-up controlled has motivated a thriving body of research over the past five decades. In this review I address two questions: 1) how do top-down and bottom-up controls influence large herbivore populations? 2) How do human activities

  19. Change Levers for Unifying Top-Down and Bottom-Up Approaches to the Adoption and Diffusion of e-Learning in Higher Education

    Science.gov (United States)

    Singh, Gurmak; Hardaker, Glenn

    2017-01-01

    Using Giddens' theory of structuration as a theoretical framework, this paper outlines how five prominent United Kingdom universities aimed to integrate top-down and bottom-up approaches to the adoption and diffusion of e-learning. The aim of this paper is to examine the major challenges that arise from the convergence of bottom-up perspectives…

  20. Prefrontal /accumbal catecholamine system processes high motivational salience.

    Directory of Open Access Journals (Sweden)

    Stefano ePuglisi-Allegra

    2012-06-01

    Full Text Available Motivational salience regulates the strength of goal seeking, the amount of risk taken, and the energy invested from mild to extreme. Highly motivational experiences promote highly persistent memories. Although this phenomenon is adaptive in normal conditions, experiences with extremely high levels of motivational salience can promote development of memories that can be re-experienced intrusively for long time resulting in maladaptive outcomes.Neural mechanisms mediating motivational salience attribution are, therefore, very important for individual and species survival and for well-being. However, these neural mechanisms could be implicated in attribution of abnormal motivational salience to different stimuli leading to maladaptive compulsive seeking or avoidance. We have offered the first evidence that prefrontal cortical norepinephrine transmission is a necessary condition for motivational salience attribution to highly salient stimuli, through modulation of dopamine in the nucleus accumbens, a brain area involved in all motivated behaviors. Moreover, we have shown that prefrontal-accumbal catecholamine system determines approach or avoidance responses to both reward- and aversion-related stimuli only when the salience of the unconditioned stimulus is high enough to induce sustained catecholamine activation, thus affirming that this system processes motivational salience attribution selectively to highly salient events.

  1. Saliency Changes Appearance

    Science.gov (United States)

    Kerzel, Dirk; Schönhammer, Josef; Burra, Nicolas; Born, Sabine; Souto, David

    2011-01-01

    Numerous studies have suggested that the deployment of attention is linked to saliency. In contrast, very little is known about how salient objects are perceived. To probe the perception of salient elements, observers compared two horizontally aligned stimuli in an array of eight elements. One of them was salient because of its orientation or direction of motion. We observed that the perceived luminance contrast or color saturation of the salient element increased: the salient stimulus looked even more salient. We explored the possibility that changes in appearance were caused by attention. We chose an event-related potential indexing attentional selection, the N2pc, to answer this question. The absence of an N2pc to the salient object provides preliminary evidence against involuntary attentional capture by the salient element. We suggest that signals from a master saliency map flow back into individual feature maps. These signals boost the perceived feature contrast of salient objects, even on perceptual dimensions different from the one that initially defined saliency. PMID:22162760

  2. Temperature regulation of marine heterotrophic prokaryotes increases latitudinally as a breach between bottom-up and top-down controls

    KAUST Repository

    Moran, Xose Anxelu G.

    2017-04-19

    Planktonic heterotrophic prokaryotes make up the largest living biomass and process most organic matter in the ocean. Determining when and where the biomass and activity of heterotrophic prokaryotes are controlled by resource availability (bottom-up), predation and viral lysis (top-down) or temperature will help in future carbon cycling predictions. We conducted an extensive survey across subtropical and tropical waters of the Atlantic, Indian and Pacific Oceans during the Malaspina 2010 Global Circumnavigation Expedition and assessed indices for these three types of controls at 109 stations (mostly from the surface to 4000 m depth). Temperature control was approached by the apparent activation energy in eV (ranging from 0.46 to 3.41), bottom-up control by the slope of the log-log relationship between biomass and production rate (ranging from -0.12 to 1.09) and top-down control by an index that considers the relative abundances of heterotrophic nanoflagellates and viruses (ranging from 0.82 to 4.83). We conclude that temperature becomes dominant (i.e. activation energy >1.5 eV) within a narrow window of intermediate values of bottom-up (0.3-0.6) and top-down 0.8-1.2) controls. A pervasive latitudinal pattern of decreasing temperature regulation towards the Equator, regardless of the oceanic basin, suggests that the impact of global warming on marine microbes and their biogeochemical function will be more intense at higher latitudes. Our analysis predicts that 1°C ocean warming will result in increased biomass of heterotrophic prokaryoplankton only in waters with <26°C of mean annual surface temperature. This article is protected by copyright. All rights reserved.

  3. Temperature regulation of marine heterotrophic prokaryotes increases latitudinally as a breach between bottom-up and top-down controls.

    Science.gov (United States)

    Morán, Xosé Anxelu G; Gasol, Josep M; Pernice, Massimo C; Mangot, Jean-François; Massana, Ramon; Lara, Elena; Vaqué, Dolors; Duarte, Carlos M

    2017-09-01

    Planktonic heterotrophic prokaryotes make up the largest living biomass and process most organic matter in the ocean. Determining when and where the biomass and activity of heterotrophic prokaryotes are controlled by resource availability (bottom-up), predation and viral lysis (top-down) or temperature will help in future carbon cycling predictions. We conducted an extensive survey across subtropical and tropical waters of the Atlantic, Indian and Pacific Oceans during the Malaspina 2010 Global Circumnavigation Expedition and assessed indices for these three types of controls at 109 stations (mostly from the surface to 4,000 m depth). Temperature control was approached by the apparent activation energy in eV (ranging from 0.46 to 3.41), bottom-up control by the slope of the log-log relationship between biomass and production rate (ranging from -0.12 to 1.09) and top-down control by an index that considers the relative abundances of heterotrophic nanoflagellates and viruses (ranging from 0.82 to 4.83). We conclude that temperature becomes dominant (i.e. activation energy >1.5 eV) within a narrow window of intermediate values of bottom-up (0.3-0.6) and top-down 0.8-1.2) controls. A pervasive latitudinal pattern of decreasing temperature regulation towards the Equator, regardless of the oceanic basin, suggests that the impact of global warming on marine microbes and their biogeochemical function will be more intense at higher latitudes. Our analysis predicts that 1°C ocean warming will result in increased biomass of heterotrophic prokaryoplankton only in waters with <26°C of mean annual surface temperature. © 2017 The Authors. Global Change Biology Published by John Wiley & Sons Ltd.

  4. Impact of spatial proxies on the representation of bottom-up emission inventories: A satellite-based analysis

    Science.gov (United States)

    Geng, Guannan; Zhang, Qiang; Martin, Randall V.; Lin, Jintai; Huo, Hong; Zheng, Bo; Wang, Siwen; He, Kebin

    2017-03-01

    Spatial proxies used in bottom-up emission inventories to derive the spatial distributions of emissions are usually empirical and involve additional levels of uncertainty. Although uncertainties in current emission inventories have been discussed extensively, uncertainties resulting from improper spatial proxies have rarely been evaluated. In this work, we investigate the impact of spatial proxies on the representation of gridded emissions by comparing six gridded NOx emission datasets over China developed from the same magnitude of emissions and different spatial proxies. GEOS-Chem-modeled tropospheric NO2 vertical columns simulated from different gridded emission inventories are compared with satellite-based columns. The results show that differences between modeled and satellite-based NO2 vertical columns are sensitive to the spatial proxies used in the gridded emission inventories. The total population density is less suitable for allocating NOx emissions than nighttime light data because population density tends to allocate more emissions to rural areas. Determining the exact locations of large emission sources could significantly strengthen the correlation between modeled and observed NO2 vertical columns. Using vehicle population and an updated road network for the on-road transport sector could substantially enhance urban emissions and improve the model performance. When further applying industrial gross domestic product (IGDP) values for the industrial sector, modeled NO2 vertical columns could better capture pollution hotspots in urban areas and exhibit the best performance of the six cases compared to satellite-based NO2 vertical columns (slope = 1.01 and R2 = 0. 85). This analysis provides a framework for information from satellite observations to inform bottom-up inventory development. In the future, more effort should be devoted to the representation of spatial proxies to improve spatial patterns in bottom-up emission inventories.

  5. The drastic outcomes from voting alliances in three-party bottom-up democratic voting (1990 $\\rightarrow$ 2013)

    OpenAIRE

    Galam, Serge

    2013-01-01

    The drastic effect of local alliances in three-party competition is investigated in democratic hierarchical bottom-up voting. The results are obtained analytically using a model which extends a sociophysics frame introduced in 1986 \\cite{psy} and 1990 \\cite{lebo} to study two-party systems and the spontaneous formation of democratic dictatorship. It is worth stressing that the 1990 paper was published in the Journal of Statistical Physics, the first paper of its kind in the journal. It was sh...

  6. Benchmarking energy scenarios for China: perspectives from top-down, economic and bottom-up, technical modelling

    DEFF Research Database (Denmark)

    This study uses a soft-linking methodology to harmonise two complex global top-down and bottom-up models with a regional China focus. The baseline follows the GDP and demographic trends of the Shared Socio-economic Pathways (SSP2) scenario, down-scaled for China, while the carbon tax scenario fol......-specific modelling results further. These new sub-regional China features can now be used for a more detailed analysis of China's regional developments in a global context....

  7. Evaluation of bottom-up and downscaled emission inventories for Paris and consequences for estimating urban air pollution increments

    Science.gov (United States)

    Timmermans, R.; Denier van der Gon, H.; Segers, A.; Honore, C.; Perrussel, O.; Builtjes, P.; Schaap, M.

    2012-04-01

    Since a major part of the Earth's population lives in cities, it is of great importance to correctly characterise the air pollution levels over these urban areas. Many studies in the past have already been dedicated to this subject and have determined so-called urban increments: the impact of large cities on the air pollution levels. The impact of large cities on air pollution levels usually is determined with models driven by so-called downscaled emission inventories. In these inventories official country total emissions are gridded using information on for example population density and location of industries and roads. The question is how accurate are the downscaled inventories over cities or large urban areas. Within the EU FP 7 project MEGAPOLI project a new emission inventory has been produced including refined local emission data for two European megacities (Paris, London) and two urban conglomerations (the Po valley, Italy and the Rhine-Ruhr region, Germany) based on a bottom-up approach. The inventory has comparable national totals but remarkable difference at the city scale. Such a bottom up inventory is thought to be more accurate as it contains local knowledge. Within this study we compared modelled nitrogen dioxide (NO2) and particulate matter (PM) concentrations from the LOTOS-EUROS chemistry transport model driven by a conventional downscaled emission inventory (TNO-MACC inventory) with the concentrations from the same model driven by the new MEGAPOLI 'bottom-up' emission inventory focusing on the Paris region. Model predictions for Paris significantly improve using the new Megapoli inventory. Both the emissions as well as the simulated average concentrations of PM over urban sites in Paris are much lower due to the different spatial distribution of the anthropogenic emissions. The difference for the nearby rural stations is small implicating that also the urban increment for PM simulated using the bottom-up emission inventory is much smaller than

  8. [Diversity in thalamic relay neurons: evidence for "bottom-up" and "top-down" information flow in thalamocortical pathways].

    Science.gov (United States)

    Clascá, Francisco; Rubio-Garrido, Pablo; Galazo, María J; Porrero, César

    2009-01-01

    Thalamocortical (TC) pathways are still mainly understood as the gateway for ascending sensory-motor information into the cortex. However, it is now clear that a great many TC cells are involved in interactions between cortical areas via the thalamus. We review recent data, including our own, which demonstrate the generalized presence in rodent thalamus of two major TC cell types characterized, among other features, by their axon development, arborization and laminar targeting in the cortex. Such duality may allow inputs from thalamus to access cortical circuits via "bottom-up"-wired axon arbors or via "top-down"-wired axon arbors.

  9. Bottom-Up Nano-heteroepitaxy of Wafer-Scale Semipolar GaN on (001) Si

    KAUST Repository

    Hus, Jui Wei

    2015-07-15

    Semipolar {101¯1} InGaN quantum wells are grown on (001) Si substrates with an Al-free buffer and wafer-scale uniformity. The novel structure is achieved by a bottom-up nano-heteroepitaxy employing self-organized ZnO nanorods as the strain-relieving layer. This ZnO nanostructure unlocks the problems encountered by the conventional AlN-based buffer, which grows slowly and contaminates the growth chamber. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Comparison of feature combination strategies for saliency-based visual attention systems

    Science.gov (United States)

    Itti, Laurent; Koch, Christof

    1999-05-01

    Bottom-up or saliency-based visual attention allows primates to detect non-specific conspicuous targets in cluttered scenes. A classical metaphor, derived from electrophysiological and psychophysical studies, describes attention as a rapidly shiftable 'spotlight'. The model described here reproduces the attentional scanpaths of this spotlight: Simple multi-scale 'feature maps' detect local spatial discontinuities in intensity, color, orientation or optical flow, and are combined into a unique 'master' or 'saliency' map. the saliency map is sequentially scanned, in order of decreasing saliency, by the focus of attention. We study the problem of combining feature maps, from different visual modalities and with unrelated dynamic ranges, into a unique saliency map. Four combination strategies are compared using three databases of natural color images: (1) Simple normalized summation, (2) linear combination with learned weights, (3) global non-linear normalization followed by summation, and (4) local non-linear competition between salient locations. Performance was measured as the number of false detections before the most salient target was found. Strategy (1) always yielded poorest performance and (2) best performance, with a 3- to 8-fold improvement in time to find a salient target. However, (2) yielded specialized systems with poor generations. Interestingly, strategy (4) and its simplified, computationally efficient approximation (3) yielded significantly better performance than (1), with up to 4-fold improvement, while preserving generality.

  11. Top-down and bottom-up factors in threat-related perception and attention in anxiety.

    Science.gov (United States)

    Sussman, Tamara J; Jin, Jingwen; Mohanty, Aprajita

    2016-12-01

    Anxiety is characterized by the anticipation of aversive future events. The importance of prestimulus anticipatory factors, such as goals and expectations, is well-established in both visual perception and attention. Nevertheless, the prioritized perception of threatening stimuli in anxiety has been attributed to the automatic processing of these stimuli and the role of prestimulus factors has been neglected. The present review will focus on the role of top-down processes that occur before stimulus onset in the perceptual and attentional prioritization of threatening stimuli in anxiety. We will review both the cognitive and neuroscience literature, showing how top-down factors, and interactions between top-down and bottom-up factors may contribute to biased perception of threatening stimuli in normal function and anxiety. The shift in focus from stimulus-driven to endogenous factors and interactions between top-down and bottom-up factors in the prioritization of threat-related stimuli represents an important conceptual advance. In addition, it may yield important clues into the development and maintenance of anxiety, as well as inform novel treatments for anxiety. Copyright © 2016 Elsevier B.V. All rights reserved.

  12. Bottom-up and top-down solid-state NMR approaches for bacterial biofilm matrix composition

    Science.gov (United States)

    Cegelski, Lynette

    2015-04-01

    The genomics and proteomics revolutions have been enormously successful in providing crucial "parts lists" for biological systems. Yet, formidable challenges exist in generating complete descriptions of how the parts function and assemble into macromolecular complexes and whole-cell assemblies. Bacterial biofilms are complex multicellular bacterial communities protected by a slime-like extracellular matrix that confers protection to environmental stress and enhances resistance to antibiotics and host defenses. As a non-crystalline, insoluble, heterogeneous assembly, the biofilm extracellular matrix poses a challenge to compositional analysis by conventional methods. In this perspective, bottom-up and top-down solid-state NMR approaches are described for defining chemical composition in complex macrosystems. The "sum-of-the-parts" bottom-up approach was introduced to examine the amyloid-integrated biofilms formed by Escherichia coli and permitted the first determination of the composition of the intact extracellular matrix from a bacterial biofilm. An alternative top-down approach was developed to define composition in Vibrio cholerae biofilms and relied on an extensive panel of NMR measurements to tease out specific carbon pools from a single sample of the intact extracellular matrix. These two approaches are widely applicable to other heterogeneous assemblies. For bacterial biofilms, quantitative parameters of matrix composition are needed to understand how biofilms are assembled, to improve the development of biofilm inhibitors, and to dissect inhibitor modes of action. Solid-state NMR approaches will also be invaluable in obtaining parameters of matrix architecture.

  13. Bottom-up diamond nanorod growth in HFCVD from nanocrystalline diamond film as a template-free method

    Science.gov (United States)

    Motahari, Hamid; Malekfar, Rasoul

    2017-07-01

    Nanocrystalline diamond (NCD) films are being used in a large number of applications. Also, diamond nanorods (DNRs) exhibit distinctive features that are not present in diamond films, because of the tunable large surface-to-volume ratio and tubular configuration. In this work, we report on the synthesis of DNRs by means of the bottom-up and template-free method from NCD films by the hot filament chemical vapor deposition system. The substrate materials used for diamond deposition were stainless steel (AISI 316) and chromium nitride-coated stainless steel. On both substrates, NCD films and then DNRs have been synthesized. The micro-Raman confirms that the synthesized structure is NCD. In addition, the grazing incident x-ray diffraction pattern confirms the presence of cubic diamond and rhombohedral diamond as a film on the CrN and Cr2N interlayer. Also, the DNRs are encased in an amorphous carbon (a-C) shell. The DNRs are grown on the NCD grains by a bottom-up technology and template-free method. Their orientations are almost random in the diamond thin-film surface. In addition, the density of DNRs on the NCD film for the CrN interlayer is more than for the stainless-steel substrate. The NCD/DNR films are dense, adhesive, continuous, and almost uniform on the CrN-coated stainless-steel substrate.

  14. Neutrino mixing and R{sub K} anomaly in U(1){sub X} models: a bottom-up approach

    Energy Technology Data Exchange (ETDEWEB)

    Bhatia, Disha; Chakraborty, Sabyasachi; Dighe, Amol [Tata Institute of Fundamental Research,Mumbai 400005 (India)

    2017-03-22

    We identify a class of U(1){sub X} models which can explain the R{sub K} anomaly and the neutrino mixing pattern, by using a bottom-up approach. The different X-charges of lepton generations account for the lepton universality violation required to explain R{sub K}. In addition to the three right-handed neutrinos needed for the Type-I seesaw mechanism, these minimal models only introduce an additional doublet Higgs and a singlet scalar. While the former helps in reproducing the quark mixing structure, the latter gives masses to neutrinos and the new gauge boson Z{sup ′}. Our bottom-up approach determines the X-charges of all particles using theoretical consistency and experimental constraints. We find the parameter space allowed by the constraints from neutral meson mixing, rare b→s decays and direct collider searches for Z{sup ′}. Such a Z{sup ′} may be observable at the ongoing run of the Large Hadron Collider with a few hundred fb{sup −1} of integrated luminosity.

  15. Smart city planning from a bottom-up approach: local communities' intervention for a smarter urban environment

    Science.gov (United States)

    Alverti, Maroula; Hadjimitsis, Diofantos; Kyriakidis, Phaedon; Serraos, Konstantinos

    2016-08-01

    The aim of this paper is to explore the concept of "smart" cities from the perspective of inclusive community participation and Geographical Information Systems (GIS).The concept of a smart city is critically analyzed, focusing on the power/knowledge implications of a "bottom-up" approach in planning and how GIS could encourage community participation in smart urban planning. The paper commences with a literature review of what it means for cities to be "smart". It draws supporting definitions and critical insights into smart cities with respect to the built environment and the human factor. The second part of the paper, analyzes the "bottom-up" approach in urban planning, focusing on community participation reviewing forms and expressions through good practices from European cities. The third part of the paper includes a debate on how smart urban cities policies and community participation interact and influence each other. Finally, the paper closes with a discussion of the insights that were found and offers recommendations on how this debate could be addressed by Information and Communication Technologies and GIS in particular.

  16. Venom Proteomics of Indonesian King Cobra, Ophiophagus hannah: Integrating Top-Down and Bottom-Up Approaches.

    Science.gov (United States)

    Petras, Daniel; Heiss, Paul; Süssmuth, Roderich D; Calvete, Juan J

    2015-06-05

    We report on the first application of top-down mass spectrometry in snake venomics. De novo sequence tags generated by, and ProSight Lite supported analysis of, combined collisional based dissotiations (CID and HCD) recorded in a hybrid LTQ Orbitrap instrument in data-dependent mode identified a number of proteins from different toxin families, namely, 11 three-finger toxins (7-7.9 kDa), a Kunitz-type inhibitor (6.3 kDa), ohanin (11.9 kDa), a novel phospholipase A2 molecule (13.8 kDa), and the cysteine-rich secretory protein (CRISP) ophanin (25 kDa) from Indonesian king cobra venom. Complementary bottom-up MS/MS analyses contributed to the completion of a locus-resolved venom phenotypic map for Ophiophagus hannah, the world's longest venomous snake and a species of medical concern across its wide distribution range in forests from India to Southeast Asia. Its venom composition, comprising 32-35 proteins/peptides from 10 protein families, is dominated by α-neurotoxins and convincingly explains the main neurotoxic effects of human envenoming caused by king cobra bite. The integration of efficient chromatographic separation of the venom's components and locus-resolved toxin identification through top-down and bottom-up MS/MS-based species-specific database searching and de novo sequencing holds promise that the future will be bright for the field of venom research.

  17. Microfluidics Enabled Bottom-Up Engineering of 3D Vascularized Tumor for Drug Discovery.

    Science.gov (United States)

    Agarwal, Pranay; Wang, Hai; Sun, Mingrui; Xu, Jiangsheng; Zhao, Shuting; Liu, Zhenguo; Gooch, Keith J; Zhao, Yi; Lu, Xiongbin; He, Xiaoming

    2017-07-25

    Development of high-fidelity three-dimensional (3D) models to recapitulate the tumor microenvironment is essential for studying tumor biology and discovering anticancer drugs. Here we report a method to engineer the 3D microenvironment of human tumors, by encapsulating cancer cells in the core of microcapsules with a hydrogel shell for miniaturized 3D culture to obtain avascular microtumors first. The microtumors are then used as the building blocks for assembling with endothelial cells and other stromal cells to create macroscale 3D vascularized tumor. Cells in the engineered 3D microenvironment can yield significantly larger tumors in vivo than 2D-cultured cancer cells. Furthermore, the 3D vascularized tumors are 4.7 and 139.5 times more resistant to doxorubicin hydrochloride (a commonly used chemotherapy drug) than avascular microtumors and 2D-cultured cancer cells, respectively. Moreover, this high drug resistance of the 3D vascularized tumors can be overcome by using nanoparticle-mediated drug delivery. The high-fidelity 3D tumor model may be valuable for studying the effect of microenvironment on tumor progression, invasion, and metastasis and for developing effective therapeutic strategy to fight against cancer.

  18. The Social Perceptual Salience Effect

    Science.gov (United States)

    Inderbitzin, Martin P.; Betella, Alberto; Lanata, Antonio; Scilingo, Enzo P.; Bernardet, Ulysses; Verschure, Paul F. M. J.

    2013-01-01

    Affective processes appraise the salience of external stimuli preparing the agent for action. So far, the relationship between stimuli, affect, and action has been mainly studied in highly controlled laboratory conditions. In order to find the generalization of this relationship to social interaction, we assess the influence of the salience of…

  19. Effects of Bottom-up and Top-down Controls and Climate Change on Estuarine Macrophyte Communities and the Ecosystem Services they Provide

    Science.gov (United States)

    Macrophytes provide important estuarine benthic habitats and support a significant portion of estuarine productivity. The composition and characteristics of these benthic communities are regulated bottom-up by resource availability and from the top-down by herbivory and predation...

  20. Things/Signs, Languages/Communication, Culture and the Costs of Consciousness: On Bottom-Up Construction of Cultural Values and New Humanism

    National Research Council Canada - National Science Library

    Emil Volek

    2014-01-01

    ...) contrasts the reductionist ideological "top-down" focus on the construction of our cultural "world" with the meandering technical "bottom-up" approach, searching for forgotten or usually omitted...

  1. Impacts of fish on phosphorus budget dynamics of some SA reservoirs : evaluating prospects of 'bottom up' phosphorus reduction in eutrophic systems through fish removal (biomanipulation)

    National Research Council Canada - National Science Library

    Harding, W.R; Hart, R.C

    2015-01-01

    ...) through remedial biomanipulation - the removal of fish to deplete internal stocks of biomass-incorporated TP and especially to restrict enhancement of TP availability through internal 'bottom up' recycling by fish...

  2. Atomic layer deposition-Sequential self-limiting surface reactions for advanced catalyst "bottom-up" synthesis

    Science.gov (United States)

    Lu, Junling; Elam, Jeffrey W.; Stair, Peter C.

    2016-06-01

    Catalyst synthesis with precise control over the structure of catalytic active sites at the atomic level is of essential importance for the scientific understanding of reaction mechanisms and for rational design of advanced catalysts with high performance. Such precise control is achievable using atomic layer deposition (ALD). ALD is similar to chemical vapor deposition (CVD), except that the deposition is split into a sequence of two self-limiting surface reactions between gaseous precursor molecules and a substrate. The unique self-limiting feature of ALD allows conformal deposition of catalytic materials on a high surface area catalyst support at the atomic level. The deposited catalytic materials can be precisely constructed on the support by varying the number and type of ALD cycles. As an alternative to the wet-chemistry based conventional methods, ALD provides a cycle-by-cycle "bottom-up" approach for nanostructuring supported catalysts with near atomic precision. In this review, we summarize recent attempts to synthesize supported catalysts with ALD. Nucleation and growth of metals by ALD on oxides and carbon materials for precise synthesis of supported monometallic catalyst are reviewed. The capability of achieving precise control over the particle size of monometallic nanoparticles by ALD is emphasized. The resulting metal catalysts with high dispersions and uniformity often show comparable or remarkably higher activity than those prepared by conventional methods. For supported bimetallic catalyst synthesis, we summarize the strategies for controlling the deposition of the secondary metal selectively on the primary metal nanoparticle but not on the support to exclude monometallic formation. As a review of the surface chemistry and growth behavior of metal ALD on metal surfaces, we demonstrate the ways to precisely tune size, composition and structure of bimetallic metal nanoparticles. The cycle-by-cycle "bottom up" construction of bimetallic (or multiple

  3. The top-down, middle-down, and bottom-up mass spectrometry approaches for characterization of histone variants and their post-translational modifications.

    Science.gov (United States)

    Moradian, Annie; Kalli, Anastasia; Sweredoski, Michael J; Hess, Sonja

    2014-03-01

    Epigenetic regulation of gene expression is, at least in part, mediated by histone modifications. PTMs of histones change chromatin structure and regulate gene transcription, DNA damage repair, and DNA replication. Thus, studying histone variants and their modifications not only elucidates their functional mechanisms in chromatin regulation, but also provides insights into phenotypes and diseases. A challenge in this field is to determine the best approach(es) to identify histone variants and their PTMs using a robust high-throughput analysis. The large number of histone variants and the enormous diversity that can be generated through combinatorial modifications, also known as histone code, makes identification of histone PTMs a laborious task. MS has been proven to be a powerful tool in this regard. Here, we focus on bottom-up, middle-down, and top-down MS approaches, including CID and electron-capture dissociation/electron-transfer dissociation based techniques for characterization of histones and their PTMs. In addition, we discuss advances in chromatographic separation that take advantage of the chemical properties of the specific histone modifications. This review is also unique in its discussion of current bioinformatic strategies for comprehensive histone code analysis. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Bottom-Up Fabrication of Nanopatterned Polymers on DNA Origami by In Situ Atom-Transfer Radical Polymerization.

    Science.gov (United States)

    Tokura, Yu; Jiang, Yanyan; Welle, Alexander; Stenzel, Martina H; Krzemien, Katarzyna M; Michaelis, Jens; Berger, Rüdiger; Barner-Kowollik, Christopher; Wu, Yuzhou; Weil, Tanja

    2016-05-04

    Bottom-up strategies to fabricate patterned polymers at the nanoscale represent an emerging field in the development of advanced nanodevices, such as biosensors, nanofluidics, and nanophotonics. DNA origami techniques provide access to distinct architectures of various sizes and shapes and present manifold opportunities for functionalization at the nanoscale with the highest precision. Herein, we conduct in situ atom-transfer radical polymerization (ATRP) on DNA origami, yielding differently nanopatterned polymers of various heights. After cross-linking, the grafted polymeric nanostructures can even stably exist in solution without the DNA origami template. This straightforward approach allows for the fabrication of patterned polymers with low nanometer resolution, which provides access to unique DNA-based functional hybrid materials. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Balancing Top-Down, Bottom-Up, and Peer-to-Peer Approaches to Sustaining Distance Training

    Directory of Open Access Journals (Sweden)

    Zane BERGE

    2006-07-01

    Full Text Available Many distance training case studies identify distance training leadership as bottom-up, whereas much of the literature suggests a need for strategic, top-down approaches. With change management as an overarching framework, approaches to sustaining distance training that originate at different levels of the organization are explored. Special attention is paid to the content of the change messages involved, guided by Rogers’ five attributes of innovations. Research of change management and distance training literature suggests a combination of approaches that should fit the organizational culture as well as correctly address genuine concerns at the various organizational levels. A properly balanced approach could lead to new levels of communication and understanding in a learning organization and to distance training being sustained as a business process

  6. The faith of a physicist reflections of a bottom-up thinker : the Gifford lectures for 1993-4

    CERN Document Server

    Polkinghorne, John C

    1994-01-01

    Is it possible to think like a scientist and yet have the faith of a Christian? Although many Westerners might say no, there are also many critically minded individuals who entertain what John Polkinghorne calls a "wistful wariness" toward religion--they feel unable to accept religion on rational grounds yet cannot dismiss it completely. Polkinghorne, both a particle physicist and Anglican priest, here explores just what rational grounds there could be for Christian beliefs, maintaining that the quest for motivated understanding is a concern shared by scientists and religious thinkers alike. Anyone who assumes that religion is based on unquestioning certainties, or that it need not take into account empirical knowledge, will be challenged by Polkinghorne's bottom-up examination of Christian beliefs about events ranging from creation to the resurrection. The author organizes his inquiry around the Nicene Creed, an early statement that continues to summarize Christian beliefs. He applies to each of its tenets ...

  7. Radiographic Evaluation of Children with Febrile Urinary Tract Infection: Bottom-Up, Top-Down, or None of the Above?

    Directory of Open Access Journals (Sweden)

    Michaella M. Prasad

    2012-01-01

    Full Text Available The proper algorithm for the radiographic evaluation of children with febrile urinary tract infection (FUTI is hotly debated. Three studies are commonly administered: renal-bladder ultrasound (RUS, voiding cystourethrogram (VCUG, and dimercapto-succinic acid (DMSA scan. However, the order in which these tests are obtained depends on the methodology followed: bottom-up or top-down. Each strategy carries advantages and disadvantages, and some groups now advocate even less of a workup (none of the above due to the current controversies about treatment when abnormalities are diagnosed. New technology is available and still under investigation, but it may help to clarify the interplay between vesicoureteral reflux, renal scarring, and dysfunctional elimination in the future.

  8. Café seminars in a bottom-up organizational development project at a Danish Radiology Department.

    Science.gov (United States)

    Niss, Karsten Ulrik

    2010-01-01

    The radiology department at a Danish regional university hospital implemented integrated RIS/PACS. In the process, it became clear that some aspects of the changes had been ignored and that the impact on the organization would be substantial. With that in mind this study was planned, and an interdisciplinary working group was appointed and tasked with implementing activities to improve the organizational environment and atmosphere in the department. One activity aimed at formulating a vision/activity plan by using café seminars to involve all employees. The plan for implementation included 35 activities to support the realization of the vision. Bottom-up organizational development does work - provided that responsibility for the process is delegated.

  9. Construction of membrane-bound artificial cells using microfluidics: a new frontier in bottom-up synthetic biology.

    Science.gov (United States)

    Elani, Yuval

    2016-06-15

    The quest to construct artificial cells from the bottom-up using simple building blocks has received much attention over recent decades and is one of the grand challenges in synthetic biology. Cell mimics that are encapsulated by lipid membranes are a particularly powerful class of artificial cells due to their biocompatibility and the ability to reconstitute biological machinery within them. One of the key obstacles in the field centres on the following: how can membrane-based artificial cells be generated in a controlled way and in high-throughput? In particular, how can they be constructed to have precisely defined parameters including size, biomolecular composition and spatial organization? Microfluidic generation strategies have proved instrumental in addressing these questions. This article will outline some of the major principles underpinning membrane-based artificial cells and their construction using microfluidics, and will detail some recent landmarks that have been achieved. © 2016 The Author(s).

  10. Integrating top-down and bottom-up nanomanufacturing: Design of nucleation and growth processes from electrolytes

    Science.gov (United States)

    Kitayaporn, Sathana

    2011-07-01

    The integration of self-propagating material growth (bottom-up) with tool-directed patterning (top-down) has great potential for minimizing the cost and reducing the time needed for manufacturing nanoscale products. This requires new molecules, algorithms, and growth processes. We describe a process called "orchestrated structure evolution" (OSE) in which one "seeds" specific locations and allows a material to spontaneously grow from these sites into the desired final pattern. Software-reconfigurable seed patterning is ideal for manufacturing flexibility, but direct-write tools are often slow: combining them with bottom-up growth is a strategy for reducing patterning times. Seeds are any nucleation initiator (nanoelectrodes, proteins, catalyst, etc.) that can be patterned using tools such as electron-beam lithography (EBL) or dip-pen nanolithography. Here, we explore the OSE concept using nanoelectrode seeds patterned with EBL and engineered Thioredoxin A (TrxA) as protein seeds. For the case of nanoelectrode seeds, we use electrodeposition to initiate copper and nickel growth that propagates into a continuous patterned film. We evaluate the trade-off between reduced pattern time and pattern degradation, and predict seed-scale interactions governing growth rate and composition using Voronoi diagrams and modified Green's function calculations. The work combines experiments and theory for a wide range of pattern length scales, driving forces, seed densities, compositions and geometries. For the case of protein seeds, we use ZnO-binding derivatives of TrxA to understand how proteins may serve as nucleation initiators for ZnO crystal growth. Our studies include thermodynamics prediction of zinc-compatible biological buffers, adsorption isotherms, and electrodeposition of protein-modified ZnO. We show that electrolyte engineering is a critical part of the process, and that the electrolyte stability and prevalence of key species must be matched with protein stability

  11. Pairing top-down and bottom-up approaches to analyze catchment scale management of water quality and quantity

    Science.gov (United States)

    Lovette, J. P.; Duncan, J. M.; Band, L. E.

    2016-12-01

    Watershed management requires information on the hydrologic impacts of local to regional land use, land cover and infrastructure conditions. Management of runoff volumes, storm flows, and water quality can benefit from large scale, "top-down" screening tools, using readily available information, as well as more detailed, "bottom-up" process-based models that explicitly track local runoff production and routing from sources to receiving water bodies. Regional scale data, available nationwide through the NHD+, and top-down models based on aggregated catchment information provide useful tools for estimating regional patterns of peak flows, volumes and nutrient loads at the catchment level. Management impacts can be estimated with these models, but have limited ability to resolve impacts beyond simple changes to land cover proportions. Alternatively, distributed process-based models provide more flexibility in modeling management impacts by resolving spatial patterns of nutrient source, runoff generation, and uptake. This bottom-up approach can incorporate explicit patterns of land cover, drainage connectivity, and vegetation extent, but are typically applied over smaller areas. Here, we first model peak flood flows and nitrogen loads across North Carolina's 70,000 NHD+ catchments using USGS regional streamflow regression equations and the SPARROW model. We also estimate management impact by altering aggregated sources in each of these models. To address the missing spatial implications of the top-down approach, we further explore the demand for riparian buffers as a management strategy, simulating the accumulation of nutrient sources along flow paths and the potential mitigation of these sources through forested buffers. We use the Regional Hydro-Ecological Simulation System (RHESSys) to model changes across several basins in North Carolina's Piedmont and Blue Ridge regions, ranging in size from 15 - 1,130 km2. The two approaches provide a complementary set of tools

  12. Reconciling Long-Term Trends in Air Quality with Bottom-up Emission Inventories for Los Angeles

    Science.gov (United States)

    Mcdonald, B. C.; Kim, S. W.; Frost, G. J.; Harley, R.; Trainer, M.

    2014-12-01

    Significant long-term changes in air quality have been observed in the United States over several decades. However, reconciling ambient observations with bottom-up emission inventories has proved challenging. In this study, we perform WRF-Chem modeling in the Los Angeles basin for carbon monoxide (CO), nitrogen oxides (NOx), volatile organic compounds (VOCs), and ozone (O3) over a long time period (1987-2010). To improve reconciliation of emission inventories with atmospheric observations, we incorporate new high-resolution emissions maps of a major to dominant source of urban air pollution, motor vehicles. A fuel-based approach is used to estimate motor vehicle emissions utilizing annual fuel sales reports, traffic count data that capture spatial and temporal patterns of vehicle activity, and pollutant emission factors measured from roadway studies performed over the last twenty years. We also update emissions from stationary sources using Continuous Emissions Monitoring Systems (CEMS) data when available, and use emission inventories developed by the South Coast Air Quality Management District (SCAQMD) and California Air Resources Board (ARB) for other important emission source categories. WRF-Chem modeling is performed in three years where field-intensive measurements were made: 1987 (SCAQS: Southern California Air Quality Study), 2002 (ITCT: Intercontinental Transport and Chemical Transformation Study), and 2010 (CALNEX). We assess the ability of the improved bottom-up emissions inventory to predict long-term changes in ambient levels of CO, NOx, and O3, which are known to have occurred over this time period. We also assess changing spatial and temporal patterns of primary (CO and NOx) and secondary (O3) pollutant concentrations across the Los Angeles basin, which has important implications on human health.

  13. Strong bottom-up effects on phytoplankton community caused by a rainfall during spring and summer in Sagami Bay, Japan

    Science.gov (United States)

    Baek, Seung Ho; Shimode, Shinji; Kim, Hyun-cheol; Han, Myung-Soo; Kikuchi, Tomohiko

    2009-01-01

    To assess the consequences of bottom-up effects on phytoplankton community composition during the rainy season, phytoplankton levels and environmental factors were monitored daily from 12 April to 22 July 2003 in Sagami Bay, Japan. The relevant environmental factors were analyzed using cross-correlation analyses. Based on time-series analysis, low surface salinity conditions lasting 0 or 2 days after heavy rainfalls resulted in significant nutrient loading, such as dissolved inorganic nitrogen (DIN), into the coastal area. Also, Chlorophyll- a (Chl- a) concentration frequently increased 2 and 6 days after rainfall. Based on the high total Chl- a concentration, the time was divided into three periods, from 1 to 11 May (Period A), 26 May to 9 June (Period B) and 30 June to 22 July (Period C). The phytoplankton assemblages during Period A were dominated by two dinoflagellates, Ceratium furca and Ceratium fusus. Prior to these species blooming, the heterotrophic dinoflagellate Noctiluca scintillans was dominant. During Period B, the phytoplankton communities were dominated primarily by the diatoms Rhizosolenia delicatula, Hemiaulus sinensis and Navicula spp. Finally, Cerataulina dentata, Rhizosolenia spp., Lauderia borealis and Neodelphineis pelagica were dominant during Period C. After increases in phytoplankton abundance, available nitrogen (N) and phosphorous (P) were consumed and exhausted, which were considered a potential cause of the shift in the dominant organisms from large diatoms to pico- and nano-plankton in the low Chl- a environment. In particular, silicate (Si) was not a major limiting factor for phytoplankton production, since the Si:DIN and Si:P ratios clearly demonstrated that there were no any potential stoichiometric Si limitations, and almost all silicate concentrations were > 2.0 µM during this study. Our results reveal that nutrient sources supplied by river discharge are a main cue for strong bottom-up effects on algal bloom succession during

  14. Fixation and saliency during search of natural scenes: the case of visual agnosia.

    Science.gov (United States)

    Foulsham, Tom; Barton, Jason J S; Kingstone, Alan; Dewhurst, Richard; Underwood, Geoffrey

    2009-07-01

    Models of eye movement control in natural scenes often distinguish between stimulus-driven processes (which guide the eyes to visually salient regions) and those based on task and object knowledge (which depend on expectations or identification of objects and scene gist). In the present investigation, the eye movements of a patient with visual agnosia were recorded while she searched for objects within photographs of natural scenes and compared to those made by students and age-matched controls. Agnosia is assumed to disrupt the top-down knowledge available in this task, and so may increase the reliance on bottom-up cues. The patient's deficit in object recognition was seen in poor search performance and inefficient scanning. The low-level saliency of target objects had an effect on responses in visual agnosia, and the most salient region in the scene was more likely to be fixated by the patient than by controls. An analysis of model-predicted saliency at fixation locations indicated a closer match between fixations and low-level saliency in agnosia than in controls. These findings are discussed in relation to saliency-map models and the balance between high and low-level factors in eye guidance.

  15. Classification of Alzheimer's disease using regional saliency maps from brain MR volumes

    Science.gov (United States)

    Pulido, Andrea; Rueda, Andrea; Romero, Eduardo

    2013-02-01

    Accurate diagnosis of Alzheimer's disease (AD) from structural Magnetic Resonance (MR) images is difficult due to the complex alteration of patterns in brain anatomy that could indicate the presence or absence of the pathology. Currently, an effective approach that allows to interpret the disease in terms of global and local changes is not available in the clinical practice. In this paper, we propose an approach for classification of brain MR images, based on finding pathology-related patterns through the identification of regional structural changes. The approach combines a probabilistic Latent Semantic Analysis (pLSA) technique, which allows to identify image regions through latent topics inferred from the brain MR slices, with a bottom-up Graph-Based Visual Saliency (GBVS) model, which calculates maps of relevant information per region. Regional saliency maps are finally combined into a single map on each slice, obtaining a master saliency map of each brain volume. The proposed approach includes a one-to-one comparison of the saliency maps which feeds a Support Vector Machine (SVM) classifier, to group test subjects into normal or probable AD subjects. A set of 156 brain MR images from healthy (76) and pathological (80) subjects, splitted into a training set (10 non-demented and 10 demented subjects) and one testing set (136 subjects), was used to evaluate the performance of the proposed approach. Preliminary results show that the proposed method reaches a maximum classification accuracy of 87.21%.

  16. A Comparative Prospective Study of Two Different Treatment Sequences i.e. Bottom Up-Inside Out and Topdown-Outside in, in the Treatment of Panfacial Fractures.

    Science.gov (United States)

    Degala, Saikrishna; Sundar, S Shyam; Mamata, K S

    2015-12-01

    To compare the sequence bottom-up inside-out with top-down outside-in, in the treatment of pan facial fractures and to evaluate the outcome of these approaches. The data from 11 patients with panfacial fracture are prospectively analysed. Five cases are treated with bottom-up approach and six patients with top-down approach. There were 11 male patients (six in top-down approach and five in bottom-up approach), ranging in age from 24 to 50 years. All injuries were result of RTA (n = 11, 100 %). Final treatment outcome was excellent in 3 (50 %), 1 (16 %) good and 2 (32 %) cases were fair in topdown approach, 3 (60 %) excellent and 2 (40 %) fair in bottom up approach with contingency coefficient value (P inside-out and top-down outside-in approaches have similar clinical outcomes. Hence it could be suggestive to start fixation of least disrupted (more stable) facial half as a guide for reconstruction of the remaining. Choice of the bottom-up inside-out or top-down outside-in sequence should be according to the pattern of fractures and preference of the surgeon. However, further controlled clinical trials, comparative studies with a larger sample size would be better to evaluate the final clinical outcome of individual techniques.

  17. Hybrid bottom-up/top-down energy and economy outlooks: a survey of the IMACLIM-S experiments

    Directory of Open Access Journals (Sweden)

    Frédéric eGhersi

    2015-11-01

    Full Text Available In this paper we survey the research undertaken at the Centre International de Recherche sur l’Environnement et le Développement (CIRED on the combination of the IMACLIM-S macroeconomic model with ‘bottom-up’ energy modeling, with a view to associate the strengths and circumvent the limitations of both approaches to energy-economy-environment (E3 prospective modeling. We start by presenting the two methodological avenues of coupling IMACLIM-S with detailed energy systems models pursued at CIRED since the late 1990s’: (1 the calibration of the behavioral functions of IMACLIM-S that represent the producers’ and consumers’ trade-offs between inputs or consumptions, on a large set of bottom-up modeling results; (2 the coupling of IMACLIM-S to some bottom-up model through the iterative exchange of some of each model’s outputs as the other model’s inputs until convergence of the exchanged data, comprising the main macroeconomic drivers and energy systems variables. In the following section, we turn to numerical application and address the prerequisite of harmonizing national accounts, energy balance and energy price data to produce consistent hybrid input-output matrices as a basis of scenario exploration. We highlight how this data treatment step reveals the discrepancies and biases induced by sticking to the conventional modeling usage of uniform pricing of homogeneous goods. IMACLIM-S rather calibrates agent-specific margins, which we introduce and comment upon. In a further section we sum up the results of 4 IMACLIM-S experiments, insisting upon the value-added of hybrid modeling. These varied experiments regard international climate policy burden sharing; the more general numerical consequences of shifting from a biased standard CGE model perspective to the hybrid IMACLIM approach; the macroeconomic consequences of a strong development of electric mobility in the European Union; and the resilience of public debts to energy shocks

  18. Thinking about the weather: How display salience and knowledge affect performance in a graphic inference task.

    Science.gov (United States)

    Hegarty, Mary; Canham, Matt S; Fabrikant, Sara I

    2010-01-01

    Three experiments examined how bottom-up and top-down processes interact when people view and make inferences from complex visual displays (weather maps). Bottom-up effects of display design were investigated by manipulating the relative visual salience of task-relevant and task-irrelevant information across different maps. Top-down effects of domain knowledge were investigated by examining performance and eye fixations before and after participants learned relevant meteorological principles. Map design and knowledge interacted such that salience had no effect on performance before participants learned the meteorological principles; however, after learning, participants were more accurate if they viewed maps that made task-relevant information more visually salient. Effects of display design on task performance were somewhat dissociated from effects of display design on eye fixations. The results support a model in which eye fixations are directed primarily by top-down factors (task and domain knowledge). They suggest that good display design facilitates performance not just by guiding where viewers look in a complex display but also by facilitating processing of the visual features that represent task-relevant information at a given display location. (PsycINFO Database Record (c) 2009 APA, all rights reserved).

  19. Encouraging the pursuit of advanced degrees in science and engineering: Top-down and bottom-up methodologies

    Science.gov (United States)

    Maddox, Anthony B.; Smith-Maddox, Renee P.; Penick, Benson E.

    1989-01-01

    The MassPEP/NASA Graduate Research Development Program (GRDP) whose objective is to encourage Black Americans, Mexican Americans, American Indians, Puerto Ricans, and Pacific Islanders to pursue graduate degrees in science and engineering is described. The GRDP employs a top-down or goal driven methodology through five modules which focus on research, graduate school climate, technical writing, standardized examinations, and electronic networking. These modules are designed to develop and reinforce some of the skills necessary to seriously consider the goal of completing a graduate education. The GRDP is a community-based program which seeks to recruit twenty participants from a pool of Boston-area undergraduates enrolled in engineering and science curriculums and recent graduates with engineering and science degrees. The program emphasizes that with sufficient information, its participants can overcome most of the barriers perceived as preventing them from obtaining graduate science and engineering degrees. Experience has shown that the top-down modules may be complemented by a more bottom-up or event-driven methodology. This approach considers events in the academic and professional experiences of participants in order to develop the personal and leadership skills necessary for graduate school and similar endeavors.

  20. Temporal shifts in top-down vs. bottom-up control of epiphytic algae in a seagrass ecosystem

    Science.gov (United States)

    Whalen, Matthew A.; Duffy, J. Emmett; Grace, James B.

    2013-01-01

    In coastal marine food webs, small invertebrate herbivores (mesograzers) have long been hypothesized to occupy an important position facilitating dominance of habitat-forming macrophytes by grazing competitively superior epiphytic algae. Because of the difficulty of manipulating mesograzers in the field, however, their impacts on community organization have rarely been rigorously documented. Understanding mesograzer impacts has taken on increased urgency in seagrass systems due to declines in seagrasses globally, caused in part by widespread eutrophication favoring seagrass overgrowth by faster-growing algae. Using cage-free field experiments in two seasons (fall and summer), we present experimental confirmation that mesograzer reduction and nutrients can promote blooms of epiphytic algae growing on eelgrass (Zostera marina). In this study, nutrient additions increased epiphytes only in the fall following natural decline of mesograzers. In the summer, experimental mesograzer reduction stimulated a 447% increase in epiphytes, appearing to exacerbate seasonal dieback of eelgrass. Using structural equation modeling, we illuminate the temporal dynamics of complex interactions between macrophytes, mesograzers, and epiphytes in the summer experiment. An unexpected result emerged from investigating the interaction network: drift macroalgae indirectly reduced epiphytes by providing structure for mesograzers, suggesting that the net effect of macroalgae on seagrass depends on macroalgal density. Our results show that mesograzers can control proliferation of epiphytic algae, that top-down and bottom-up forcing are temporally variable, and that the presence of macroalgae can strengthen top-down control of epiphytic algae, potentially contributing to eelgrass persistence.

  1. The conquest of middle-earth: combining top-down and bottom-up nanofabrication for constructing nanoparticle based devices.

    Science.gov (United States)

    Diaz Fernandez, Yuri A; Gschneidtner, Tina A; Wadell, Carl; Fornander, Louise H; Lara Avila, Samuel; Langhammer, Christoph; Westerlund, Fredrik; Moth-Poulsen, Kasper

    2014-12-21

    The development of top-down nanofabrication techniques has opened many possibilities for the design and realization of complex devices based on single molecule phenomena such as e.g. single molecule electronic devices. These impressive achievements have been complemented by the fundamental understanding of self-assembly phenomena, leading to bottom-up strategies to obtain hybrid nanomaterials that can be used as building blocks for more complex structures. In this feature article we highlight some relevant published work as well as present new experimental results, illustrating the versatility of self-assembly methods combined with top-down fabrication techniques for solving relevant challenges in modern nanotechnology. We present recent developments on the use of hierarchical self-assembly methods to bridge the gap between sub-nanometer and micrometer length scales. By the use of non-covalent self-assembly methods, we show that we are able to control the positioning of nanoparticles on surfaces, and to address the deterministic assembly of nano-devices with potential applications in plasmonic sensing and single-molecule electronics experiments.

  2. Top-Down and Bottom-Up Approaches in 3D Printing Technologies for Drug Delivery Challenges.

    Science.gov (United States)

    Katakam, Prakash; Dey, Baishakhi; Assaleh, Fathi H; Hwisa, Nagiat Tayeb; Adiki, Shanta Kumari; Chandu, Babu Rao; Mitra, Analava

    2015-01-01

    3-Dimensional printing (3DP) constitutes a raft of technologies, based on different physical mechanisms, that generate a 3-dimensional physical object from a digital model. Because of its rapid fabrication and precise geometry, 3DP has gained a prominent focus in biomedical and nanobiomaterials research. Despite advancements in targeted, controlled, and pulsatile drug delivery, the achievement of site-specific and disease-responsive drug release and stringent control over in vivo biodistribution, are still some of the important, challenging areas for pharmaceutical research and development and existing drug delivery techniques. Microelectronic industries are capable of generating nano-/microdrug delivery devices at high throughputs with a highly precise control over design. Successful miniaturizations of micro-pumps with multireservoir architectures for delivery of pharmaceuticals developed by micro-electromechanical systems technology were more acceptable than implantable devices. Inkjet printing technologies, which dispense a precise amount of polymer ink solutions, find applications in controlled drug delivery. Bioelectronic products have revolutionized drug delivery technologies. Designing nanoparticles by nanoimprint lithography showed a controlled drug release pattern, biodistribution, and in vivo transport. This review highlights the "top-down" and "bottom-up" approaches of the most promising 3DP technologies and their broader applications in biomedical and therapeutic drug delivery, with critical assessment of its merits, demerits, and intellectual property rights challenges.

  3. D-Branes at Singularities A Bottom-Up Approach to the String Embedding of the Standard Model

    CERN Document Server

    Aldazabal, G.; Quevedo, F.; Uranga, A.M.

    2000-01-01

    We propose a bottom-up approach to the building of particle physics models from string theory. Our building blocks are Type II D-branes which we combine appropriately to reproduce desirable features of a particle theory model: 1) Chirality ; 2) Standard Model group ; 3) N=1 or N=0 supersymmetry ; 4) Three quark-lepton generations. We start such a program by studying configurations of D=10, Type IIB D3-branes located at singularities. We study in detail the case of Z_N, N=1,0 supersymmetric orbifold singularities leading to the SM group or some left-right symmetricextension. In general, tadpole cancellation conditions require the presence of additional branes, e.g. D7-branes. For the N=1 supersymmetric case the unique twist leading to three quark-lepton generations is Z_3, predicting $\\sin^2\\theta_W=3/14=0.21$. The models obtained are the simplest semirealistic string models ever built. In the non-supersymmetric case there is a three-generation model for each Z_N, N>4, but the Weinberg angle is in general too ...

  4. A bottom-up robust optimization framework for identifying river basin development pathways under deep climate uncertainty

    Science.gov (United States)

    Taner, M. U.; Ray, P.; Brown, C.

    2016-12-01

    Hydroclimatic nonstationarity due to climate change poses challenges for long-term water infrastructure planning in river basin systems. While designing strategies that are flexible or adaptive hold intuitive appeal, development of well-performing strategies requires rigorous quantitative analysis that address uncertainties directly while making the best use of scientific information on the expected evolution of future climate. Multi-stage robust optimization (RO) offers a potentially effective and efficient technique for addressing the problem of staged basin-level planning under climate change, however the necessity of assigning probabilities to future climate states or scenarios is an obstacle to implementation, given that methods to reliably assign probabilities to future climate states are not well developed. We present a method that overcomes this challenge by creating a bottom-up RO-based framework that decreases the dependency on probability distributions of future climate and rather employs them after optimization to aid selection amongst competing alternatives. The iterative process yields a vector of `optimal' decision pathways each under the associated set of probabilistic assumptions. In the final phase, the vector of optimal decision pathways is evaluated to identify the solutions that are least sensitive to the scenario probabilities and are most-likely conditional on the climate information. The framework is illustrated for the planning of new dam and hydro-agricultural expansions projects in the Niger River Basin over a 45-year planning period from 2015 to 2060.

  5. Evaluating the impact of odors from the 1955 landfills in China using a bottom-up approach.

    Science.gov (United States)

    Cai, Bofeng; Wang, Jinnan; Long, Ying; Li, Wanxin; Liu, Jianguo; Ni, Zhe; Bo, Xin; Li, Dong; Wang, Jianghao; Chen, Xuejing; Gao, Qingxian; Zhang, Lixiao

    2015-12-01

    Landfill odors have created a major concern for the Chinese public. Based on the combination of a first order decay (FOD) model and a ground-level point source Gaussian dispersion model, the impacts from odors emitted from the 1955 landfills in China are evaluated in this paper. Our bottom-up approach uses basic data related to each landfill to achieve a more accurate and comprehensive understanding of impact of landfill odors. Results reveal that the average radius of impact of landfill odors in China is 796 m, while most landfills (46.85%) are within the range of 400-1000 m, in line with the results from previous studies. The total land area impacted by odors has reached 837,476 ha, accounting for 0.09% of China's land territory. Guangdong and Sichuan provinces have the largest land areas impacted by odors, while Tibet Autonomous Region and Tianjin Municipality have the smallest. According to the CALPUFF (California Puff) model and an analysis of social big data, the overall uncertainty of our calculation of the range of odor impacts is roughly -32.88% to 32.67%. This type of study is essential for gaining an accurate and detailed estimation of the affected human population and will prove valuable for addressing the current Not In My Back Yard (NIMBY) challenge in China. Copyright © 2015 Elsevier Ltd. All rights reserved.

  6. The Challenges of Bottom-up Approach of Natural-Social Integration in China Highland Pasture Management

    Science.gov (United States)

    Ai, Likun

    2017-04-01

    The pasture land covers two fifth of total Chinese land area, which is mainly distributed in western highland of Inner Mongolia, Xinjiang, Tibet, Qinghai, Gansu and Sichuan Provinces. China pasture land is not only in charge of providing food resource to regional people, but also plays important role in highland ecosystem services and biodiversity. Along with global warming and enhanced grazing activity, 90% of China pasture land is facing the threat of land degradation. From middle 1990's, Chinese government has released a series of pasture land conservation policies to prevent further environmental degradation. In the same time, lots of pasture ecosystem and environment change researches are supported by national and regional funding agencies. In this study, by monitoring and investigating this top-down approach of pasture land research and policy making processes, we would like to find out the gaps and problems of current research and policy making on China pasture land conservation, especially focusing on the possibility of establishing the bottom-up approach of natural-social sciences integration to support the pasture land conservation and sustainable pasture land management in highland China.

  7. Erosion rates as a potential bottom-up control of forest structural characteristics in the Sierra Nevada Mountains.

    Science.gov (United States)

    Milodowski, David T; Mudd, Simon M; Mitchard, Edward T A

    2015-01-01

    The physical characteristics of landscapes place fundamental constraints on vegetation growth and ecosystem function. In actively eroding landscapes, many of these characteristics are controlled by long-term erosion rates: increased erosion rates generate steeper topography and reduce the depth and extent of weathering, limiting moisture storage capacity and impacting nutrient availability. Despite the potentially important bottom-up control that erosion rates place on substrate characteristics, the relationship between the two is largely unexplored. We investigate spatial variations in aboveground biomass (AGB) across a structurally diverse mixed coniferous/deciduous forest with an order of magnitude erosion-rate gradient in the Northern Californian Sierra Nevada, USA, using high resolution LiDAR data and field plots. Mean basin slope, a proxy for erosion rate, accounts for 32% of variance in AGB within our field area (P < 0.001), considerably outweighing the effects of mean annual precipitation, temperature, and bedrock lithology. This highlights erosion rate as a potentially important, but hitherto unappreciated, control on AGB and forest structure.

  8. Estimation of Emissions from Sugarcane Field Burning in Thailand Using Bottom-Up Country-Specific Activity Data

    Directory of Open Access Journals (Sweden)

    Wilaiwan Sornpoon

    2014-09-01

    Full Text Available Open burning in sugarcane fields is recognized as a major source of air pollution. However, the assessment of its emission intensity in many regions of the world still lacks information, especially regarding country-specific activity data including biomass fuel load and combustion factor. A site survey was conducted covering 13 sugarcane plantations subject to different farm management practices and climatic conditions. The results showed that pre-harvest and post-harvest burnings are the two main practices followed in Thailand. In 2012, the total production of sugarcane biomass fuel, i.e., dead, dry and fresh leaves, amounted to 10.15 million tonnes, which is equivalent to a fuel density of 0.79 kg∙m−2. The average combustion factor for the pre-harvest and post-harvest burning systems was determined to be 0.64 and 0.83, respectively. Emissions from sugarcane field burning were estimated using the bottom-up country-specific values from the site survey of this study and the results compared with those obtained using default values from the 2006 IPCC Guidelines. The comparison showed that the use of default values lead to underestimating the overall emissions by up to 30% as emissions from post-harvest burning are not accounted for, but it is the second most common practice followed in Thailand.

  9. The Impact of Bottom-Up Parking Information Provision in a Real-Life Context: The Case of Antwerp

    Directory of Open Access Journals (Sweden)

    Geert Tasseron

    2017-01-01

    Full Text Available A number of studies have analyzed the possible impacts of bottom-up parking information or parking reservation systems on parking dynamics in abstract simulation environments. In this paper, we take these efforts one step further by investigating the impacts of these systems in a real-life context: the center of the city of Antwerp, Belgium. In our simulation, we assume that all on-street and off-street parking places are equipped with technology able to transmit their occupancy status to so-called smart cars, which can receive information and reserve a parking place. We employ PARKAGENT, an agent-based simulation model, to simulate the behavior of smart and regular cars. We obtain detailed data on parking demand from FEATHERS, an activity-based transport model. The simulation results show that parking information and reservation hardly impact search time but do reduce walking distance for smart cars, leading to a reduction in total parking time, that is, the sum of search time and walking time. Reductions in search time occur only in zones with high occupancy rates, while a drop in walking distance is especially observed in low occupancy areas. Societal benefits of parking information and reservation are limited, because of the low impact on search time and the possible negative health effects of reduced walking distance.

  10. A bottom-up, scientist-based initiative for the communication of climate sciences with the general public

    Science.gov (United States)

    Bourqui, Michel; Bolduc, Cassandra; Paul, Charbonneau; Marie, Charrière; Daniel, Hill; Angelica, Lopez; Enrique, Loubet; Philippe, Roy; Barbara, Winter

    2015-04-01

    This talk introduces a scientists-initiated, new online platform whose aim is to contribute to making climate sciences become public knowledge. It takes a unique bottom-up approach, strictly founded on individual-based participation, high scientific standards and independence The main purpose is to build an open-access, multilingual and peer-reviewed journal publishing short climate articles in non-scientific language. The targeted public includes journalists, teachers, students, local politicians, economists, members of the agriculture sector, and any other citizens from around the world with an interest in climate sciences. This journal is meant to offer a simple and direct channel for scientists wishing to disseminate their research to the general public. A high standard of climate articles is ensured through: a) requiring that the main author is an active climate scientist, and b) an innovative peer-review process involving scientific and non-scientific referees with distinct roles. The platform fosters the direct participation of non-scientists through co-authoring, peer-reviewing, language translation. It furthermore engages the general public in the scientific inquiry by allowing non-scientists to invite manuscripts to be written on topics of their concern. The platform is currently being developed by a community of scientists and non-scientists. In this talk, I will present the basic ideas behind this new online platform, its current state and the plans for the next future. The beta version of the platform is available at: http://www.climateonline.bourquiconsulting.ch

  11. Discrepancies and Uncertainties in Bottom-up Gridded Inventories of Livestock Methane Emissions for the Contiguous United States.

    Science.gov (United States)

    Hristov, Alexander; Harper, Michael; Meinen, Robert; Day, Rick; Lopes, Juliana; Ott, Troy L; Venkatesh, Aranya; Randles, Cynthia A

    2017-11-02

    In this analysis we used a spatially-explicit, simplified bottom-up approach, based on animal inventories, feed dry matter intake, and feed intake-based emission factors to estimate county-level enteric methane emissions for cattle and manure methane emissions for cattle, swine, and poultry for the contiguous United States. Overall, this analysis yielded total livestock methane emissions (8,916 Gg/yr; lower and upper 95% confidence bounds of ±19.3%) for 2012 (last census of agriculture) that are comparable to the current USEPA estimates for 2012 and to estimates from the global gridded Emission Database for Global Atmospheric Research (EDGAR) inventory. However, the spatial distribution of emissions developed in this analysis differed significantly from that of EDGAR and a recent gridded inventory based on USEPA. Combined enteric and manure methane emissions from livestock in Texas and California (highest contributors to the national total) in this study were 36% lesser and 100% greater, respectively, than estimates by EDGAR. The spatial distribution of emissions in gridded inventories (e.g., EDGAR) likely strongly impacts the conclusions of top-down approaches that use them, especially in the source attribution of resulting (posterior) emissions, and hence conclusions from such studies should be interpreted with caution.

  12. Developing a Cognitive Training Strategy for First-Episode Schizophrenia: Integrating Bottom-Up and Top-Down Approaches

    Science.gov (United States)

    Nuechterlein, Keith H.; Ventura, Joseph; Subotnik, Kenneth L.; Hayata, Jacqueline N.; Medalia, Alice; Bell, Morris D.

    2014-01-01

    It is clear that people with schizophrenia typically have cognitive problems in multiple domains as part of their illness. The cognitive deficits are among the main contributors to limitations in their everyday functioning, including their work recovery. Cognitive remediation has been applied successfully to help people with long-term, persistent schizophrenia to improve their cognitive functioning, but it is only beginning to be applied with individuals who have recently had a first episode of psychosis. Several different approaches to cognitive training have been developed. Some approaches emphasize extensive systematic practice with lower-level cognitive processes and building toward higher-level processes (“bottom-up”), while others emphasize greater focus on high-level cognitive processes that normally integrate and organize lower-level processes (“top-down”). Each approach has advantages and disadvantages for a disorder like schizophrenia, with its multiple levels of cognitive dysfunction. In addition, approaches to cognitive remediation differ in the extent to which they systematically facilitate transfer of learning to everyday functioning. We describe in this article the cognitive training approach that was developed for a UCLA study of people with a recent first episode of schizophrenia, a group that may benefit greatly from early intervention that focuses on cognition and recovery of work functioning. This approach integrated bottom-up and top-down computerized cognitive training and incorporated an additional weekly group session to bridge between computerized training and application to everyday work and school functioning. PMID:25489275

  13. Biochemistry-directed hollow porous microspheres: bottom-up self-assembled polyanion-based cathodes for sodium ion batteries

    Science.gov (United States)

    Lin, Bo; Li, Qiufeng; Liu, Baodong; Zhang, Sen; Deng, Chao

    2016-04-01

    Biochemistry-directed synthesis of functional nanomaterials has attracted great interest in energy storage, catalysis and other applications. The unique ability of biological systems to guide molecule self-assembling facilitates the construction of distinctive architectures with desirable physicochemical characteristics. Herein, we report a biochemistry-directed ``bottom-up'' approach to construct hollow porous microspheres of polyanion materials for sodium ion batteries. Two kinds of polyanions, i.e. Na3V2(PO4)3 and Na3.12Fe2.44(P2O7)2, are employed as cases in this study. The microalgae cell realizes the formation of a spherical ``bottom'' bio-precursor. Its tiny core is subjected to destruction and its tough shell tends to carbonize upon calcination, resulting in the hollow porous microspheres for the ``top'' product. The nanoscale crystals of the polyanion materials are tightly enwrapped by the highly-conductive framework in the hollow microsphere, resulting in the hierarchical nano-microstructure. The whole formation process is disclosed as a ``bottom-up'' mechanism. Moreover, the biochemistry-directed self-assembly process is confirmed to play a crucial role in the construction of the final architecture. Taking advantage of the well-defined hollow-microsphere architecture, the abundant interior voids and the highly-conductive framework, polyanion materials show favourable sodium-intercalation kinetics. Both materials are capable of high-rate long-term cycling. After five hundred cycles at 20 C and 10 C, Na3V2(PO4)3 and Na3.12Fe2.44(P2O7)2 retain 96.2% and 93.1% of the initial capacity, respectively. Therefore, the biochemistry-directed technique provides a low-cost, highly-efficient and widely applicable strategy to produce high-performance polyanion-based cathodes for sodium ion batteries.Biochemistry-directed synthesis of functional nanomaterials has attracted great interest in energy storage, catalysis and other applications. The unique ability of

  14. Estimation of the measurement uncertainty by the bottom-up approach for the determination of methamphetamine and amphetamine in urine.

    Science.gov (United States)

    Lee, Sooyeun; Choi, Hyeyoung; Kim, Eunmi; Choi, Hwakyung; Chung, Heesun; Chung, Kyu Hyuck

    2010-05-01

    The measurement uncertainty (MU) of methamphetamine (MA) and amphetamine (AP) was estimated in an authentic urine sample with a relatively low concentration of MA and AP using the bottom-up approach. A cause and effect diagram was deduced; the amount of MA or AP in the sample, the volume of the sample, method precision, and sample effect were considered uncertainty sources. The concentrations of MA and AP in the urine sample with their expanded uncertainties were 340.5 +/- 33.2 ng/mL and 113.4 +/- 15.4 ng/mL, respectively, which means 9.7% and 13.6% of the concentration gave an estimated expanded uncertainty, respectively. The largest uncertainty originated from sample effect and method precision in MA and AP, respectively, but the uncertainty of the volume of the sample was minimal in both. The MU needs to be determined during the method validation process to assess test reliability. Moreover, the identification of the largest and/or smallest uncertainty source can help improve experimental protocols.

  15. Trophic cascades of bottom-up and top-down forcing on nutrients and plankton in the Kattegat, evaluated by modelling

    DEFF Research Database (Denmark)

    Petersen, Marcell Elo; Maar, Marie; Larsen, Janus

    2017-01-01

    The aim of the study was to investigate the relative importance of bottom-up and top-down forcing on trophic cascades in the pelagic food-web and the implications for water quality indicators (summer phytoplankton biomass and winter nutrients) in relation to management. The 3D ecological model...... ERGOM was validated and applied in a local set-up of the Kattegat, Denmark, using the off-line Flexsem framework. The model scenarios were conducted by changing the forcing by ±20% of nutrient inputs (bottom-up) and mesozooplankton mortality (top-down), and both types of forcing combined. The model...... results showed that cascading effects operated differently depending on the forcing type. In the single-forcing bottom-up scenarios, the cascade directions were in the same direction as the forcing. For scenarios involving top-down, there was a skipped-level-transmission in the trophic responses...

  16. Applying bottom-up material flow analysis to identify the system boundaries of non-energy use data in international energy statistics

    OpenAIRE

    Weiss, M; Neelis, M.L.; Zuidberg, M.C.; Patel, M.K.

    2008-01-01

    Data on the non-energy use of fossil fuels in energy statistics are subject to major uncertainties. We apply a simple bottom-up methodology to recalculate non-energy use for the entire world and for the 50 countries with the highest consumption of fossil fuels for non-energy purposes. We quantify worldwide non-energy use in the year 2000 to be 24±2 exajoules (EJ), thereby accounting for 6% of the global total primary energy supply (TPES). Our bottom-up estimates are in line with data from int...

  17. Layer-by-layer assembly as a versatile bottom-up nanofabrication technique for exploratory research and realistic application.

    Science.gov (United States)

    Ariga, Katsuhiko; Hill, Jonathan P; Ji, Qingmin

    2007-05-21

    The layer-by-layer (LbL) adsorption technique offers an easy and inexpensive process for multilayer formation and allows a variety of materials to be incorporated within the film structures. Therefore, the LbL assembly method can be regarded as a versatile bottom-up nanofabrication technique. Research fields concerned with LbL assembly have developed rapidly but some important physicochemical aspects remain uninvestigated. In this review, we will introduce several examples from physicochemical investigations regarding the basics of this method to advanced research aimed at practical applications. These are selected mostly from recent reports and should stimulate many physical chemists and chemical physicists in the further development of LbL assembly. In order to further understand the mechanism of the LbL assembly process, theoretical work, including thermodynamics calculations, has been conducted. Additionally, the use of molecular dynamics simulation has been proposed. Recently, many kinds of physicochemical molecular interactions, including hydrogen bonding, charge transfer interactions, and stereo-complex formation, have been used. The combination of the LbL method with other fabrication techniques such as spin-coating, spraying, and photolithography has also been extensively researched. These improvements have enabled preparation of LbL films composed of various materials contained in well-designed nanostructures. The resulting structures can be used to investigate basic physicochemical phenomena where relative distances between interacting groups is of great importance. Similarly, LbL structures prepared by such advanced techniques are used widely for development of functional systems for physical applications from photovoltaic devices and field effect transistors to biochemical applications including nano-sized reactors and drug delivery systems.

  18. Assessment of Historic Trend in Mobility and Energy Use in India Transportation Sector Using Bottom-up Approach

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Nan; McNeil, Michael A.

    2009-05-01

    Transportation mobility in India has increased significantly in the past decades. From 1970 to 2000, motorized mobility (passenger-km) has risen by 888%, compared with an 88% population growth (Singh,2006). This contributed to many energy and environmental issues, and an energy strategy incorporates efficiency improvement and other measures needs to be designed. Unfortunately, existing energy data do not provide information on driving forces behind energy use and sometime show large inconsistencies. Many previous studies address only a single transportation mode such as passenger road travel; did not include comprehensive data collection or analysis has yet been done, or lack detail on energy demand by each mode and fuel mix. The current study will fill a considerable gap in current efforts, develop a data base on all transport modes including passenger air and water, and freight in order to facilitate the development of energy scenarios and assess significance of technology potential in a global climate change model. An extensive literature review and data collection has been done to establish the database with breakdown of mobility, intensity, distance, and fuel mix of all transportation modes. Energy consumption was estimated and compared with aggregated transport consumption reported in IEA India transportation energy data. Different scenarios were estimated based on different assumptions on freight road mobility. Based on the bottom-up analysis, we estimated that the energy consumption from 1990 to 2000 increased at an annual growth rate of 7% for the mid-range road freight growth case and 12% for the high road freight growth case corresponding to the scenarios in mobility, while the IEA data only shows a 1.7% growth rate in those years.

  19. Independent effects of bottom-up temporal expectancy and top-down spatial attention. An audiovisual study using rhythmic cueing.

    Directory of Open Access Journals (Sweden)

    Alexander eJones

    2015-01-01

    Full Text Available Selective attention to a spatial location has shown enhance perception and facilitate behaviour for events at attended locations. However, selection relies not only on where but also when an event occurs. Recently, interest has turned to how intrinsic neural oscillations in the brain entrain to rhythms in our environment, and, stimuli appearing in or out of synch with a rhythm have shown to modulate perception and performance. Temporal expectations created by rhythms and spatial attention are two processes which have independently shown to affect stimulus processing but it remains largely unknown how, and if, they interact. In four separate tasks, this study investigated the effects of voluntary spatial attention and bottom-up temporal expectations created by rhythms in both unimodal and crossmodal conditions. In each task the participant used an informative cue, either colour or pitch, to direct their covert spatial attention to the left or right, and respond as quickly as possible to a target. The lateralized target (visual or auditory was then presented at the attended or unattended side. Importantly, although not task relevant, the cue was a rhythm of either flashes or beeps. The target was presented in or out of sync (early or late with the rhythmic cue. The results showed participants were faster responding to spatially attended compared to unattended targets in all tasks. Moreover, there was an effect of rhythmic cueing upon response times in both unimodal and crossmodal conditions. Responses were faster to targets presented in sync with the rhythm compared to when they appeared too early in both crossmodal tasks. That is, rhythmic stimuli in one modality influenced the temporal expectancy in the other modality, suggesting temporal expectancies created by rhythms are crossmodal. Interestingly, there was no interaction between top-down spatial attention and rhythmic cueing in any task suggesting these two processes largely influenced

  20. Bottom-up engineering of biological systems through standard bricks: a modularity study on basic parts and devices.

    Science.gov (United States)

    Pasotti, Lorenzo; Politi, Nicolò; Zucca, Susanna; Cusella De Angelis, Maria Gabriella; Magni, Paolo

    2012-01-01

    Modularity is a crucial issue in the engineering world, as it enables engineers to achieve predictable outcomes when different components are interconnected. Synthetic Biology aims to apply key concepts of engineering to design and construct new biological systems that exhibit a predictable behaviour. Even if physical and measurement standards have been recently proposed to facilitate the assembly and characterization of biological components, real modularity is still a major research issue. The success of the bottom-up approach strictly depends on the clear definition of the limits in which biological functions can be predictable. The modularity of transcription-based biological components has been investigated in several conditions. First, the activity of a set of promoters was quantified in Escherichia coli via different measurement systems (i.e., different plasmids, reporter genes, ribosome binding sites) relative to an in vivo reference promoter. Second, promoter activity variation was measured when two independent gene expression cassettes were assembled in the same system. Third, the interchangeability of input modules (a set of constitutive promoters and two regulated promoters) connected to a fixed output device (a logic inverter) expressing GFP was evaluated. The three input modules provide tunable transcriptional signals that drive the output device. If modularity persists, identical transcriptional signals trigger identical GFP outputs. To verify this, all the input devices were individually characterized and then the input-output characteristic of the logic inverter was derived in the different configurations. Promoters activities (referred to a standard promoter) can vary when they are measured via different reporter devices (up to 22%), when they are used within a two-expression-cassette system (up to 35%) and when they drive another device in a functionally interconnected circuit (up to 44%). This paper provides a significant contribution to the

  1. Wave disturbance overwhelms top-down and bottom-up control of primary production in California kelp forests.

    Science.gov (United States)

    Reed, Daniel C; Rassweiler, Andrew; Carr, Mark H; Cavanaugh, Kyle C; Malone, Daniel P; Siegel, David A

    2011-11-01

    We took advantage of regional differences in environmental forcing and consumer abundance to examine the relative importance of nutrient availability (bottom-up), grazing pressure (top-down), and storm waves (disturbance) in determining the standing biomass and net primary production (NPP) of the giant kelp Macrocystis pyrifera in central and southern California. Using a nine-year data set collected from 17 sites we show that, despite high densities of sea urchin grazers and prolonged periods of low nutrient availability in southern California, NPP by giant kelp was twice that of central California where nutrient concentrations were consistently high and sea urchins were nearly absent due to predation by sea otters. Waves associated with winter storms were consistently higher in central California, and the loss of kelp biomass to winter wave disturbance was on average twice that of southern California. These observations suggest that the more intense wave disturbance in central California limited NPP by giant kelp under otherwise favorable conditions. Regional patterns of interannual variation in NPP were similar to those of wave disturbance in that year-to-year variation in disturbance and NPP were both greater in southern California. Our findings provide strong evidence that regional differences in wave disturbance overwhelmed those of nutrient supply and grazing intensity to determine NPP by giant kelp. The important role of disturbance in controlling NPP revealed by our study is likely not unique to giant kelp forests, as vegetation dynamics in many systems are dominated by post-disturbance succession with climax communities being relatively uncommon. The effects of disturbance frequency may be easier to detect in giant kelp because it is fast growing and relatively short lived, with cycles of disturbance and recovery occurring on time scales of years. Much longer data sets (decades to centuries) will likely be needed to properly evaluate the role of

  2. A Bottom-up Vulnerability Analysis of Water Systems with Decentralized Decision Making and Demographic Shifts- the Case of Jordan.

    Science.gov (United States)

    Lachaut, T.; Yoon, J.; Klassert, C. J. A.; Talozi, S.; Mustafa, D.; Knox, S.; Selby, P. D.; Haddad, Y.; Gorelick, S.; Tilmant, A.

    2016-12-01

    Probabilistic approaches to uncertainty in water systems management can face challenges of several types: non stationary climate, sudden shocks such as conflict-driven migrations, or the internal complexity and dynamics of large systems. There has been a rising trend in the development of bottom-up methods that place focus on the decision side instead of probability distributions and climate scenarios. These approaches are based on defining acceptability thresholds for the decision makers and considering the entire range of possibilities over which such thresholds are crossed. We aim at improving the knowledge on the applicability and relevance of this approach by enlarging its scope beyond climate uncertainty and single decision makers; thus including demographic shifts, internal system dynamics, and multiple stakeholders at different scales. This vulnerability analysis is part of the Jordan Water Project and makes use of an ambitious multi-agent model developed by its teams with the extensive cooperation of the Ministry of Water and Irrigation of Jordan. The case of Jordan is a relevant example for migration spikes, rapid social changes, resource depletion and climate change impacts. The multi-agent modeling framework used provides a consistent structure to assess the vulnerability of complex water resources systems with distributed acceptability thresholds and stakeholder interaction. A proof of concept and preliminary results are presented for a non-probabilistic vulnerability analysis that involves different types of stakeholders, uncertainties other than climatic and the integration of threshold-based indicators. For each stakeholder (agent) a vulnerability matrix is constructed over a multi-dimensional domain, which includes various hydrologic and/or demographic variables.

  3. Across-proteome modeling of dimer structures for the bottom-up assembly of protein-protein interaction networks.

    Science.gov (United States)

    Maheshwari, Surabhi; Brylinski, Michal

    2017-05-12

    Deciphering complete networks of interactions between proteins is the key to comprehend cellular regulatory mechanisms. A significant effort has been devoted to expanding the coverage of the proteome-wide interaction space at molecular level. Although a growing body of research shows that protein docking can, in principle, be used to predict biologically relevant interactions, the accuracy of the across-proteome identification of interacting partners and the selection of near-native complex structures still need to be improved. In this study, we developed a new method to discover and model protein interactions employing an exhaustive all-to-all docking strategy. This approach integrates molecular modeling, structural bioinformatics, machine learning, and functional annotation filters in order to provide interaction data for the bottom-up assembly of protein interaction networks. Encouragingly, the success rates for dimer modeling is 57.5 and 48.7% when experimental and computer-generated monomer structures are employed, respectively. Further, our protocol correctly identifies 81% of protein-protein interactions at the expense of only 19% false positive rate. As a proof of concept, 61,913 protein-protein interactions were confidently predicted and modeled for the proteome of E. coli. Finally, we validated our method against the human immune disease pathway. Protein docking supported by evolutionary restraints and machine learning can be used to reliably identify and model biologically relevant protein assemblies at the proteome scale. Moreover, the accuracy of the identification of protein-protein interactions is improved by considering only those protein pairs co-localized in the same cellular compartment and involved in the same biological process. The modeling protocol described in this communication can be applied to detect protein-protein interactions in other organisms and pathways as well as to construct dimer structures and estimate the confidence of protein

  4. A Bottom-up Energy Efficiency Improvement Roadmap for China’s Iron and Steel Industry up to 2050

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Qi [Northeastern Univ., Shenyang (China); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Hasanbeigi, Ali [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Price, Lynn [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Lu, Hongyou [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Arens, Marlene [Fraunhofer Inst. for Systems and Innovation Research (ISI), Karlsruhe (Germany)

    2016-09-01

    Iron and steel manufacturing is energy intensive in China and in the world. China is the world largest steel producer accounting for around half of the world steel production. In this study, we use a bottom-up energy consumption model to analyze four steel-production and energy-efficiency scenarios and evaluate the potential for energy savings from energy-efficient technologies in China’s iron and steel industry between 2010 and 2050. The results show that China’s steel production will rise and peak in the year 2020 at 860 million tons (Mt) per year for the base-case scenario and 680 Mt for the advanced energy-efficiency scenario. From 2020 on, production will gradually decrease to about 510 Mt and 400 Mt in 2050, for the base-case and advanced scenarios, respectively. Energy intensity will decrease from 21.2 gigajoules per ton (G/t) in 2010 to 12.2 GJ/t and 9.9 GJ/t in 2050 for the base-case and advanced scenarios, respectively. In the near term, decreases in iron and steel industry energy intensity will come from adoption of energy-efficient technologies. In the long term, a shift in the production structure of China’s iron and steel industry, reducing the share of blast furnace/basic oxygen furnace production and increasing the share of electric-arc furnace production while reducing the use of pig iron as a feedstock to electric-arc furnaces will continue to reduce the sector’s energy consumption. We discuss barriers to achieving these energy-efficiency gains and make policy recommendations to support improved energy efficiency and a shift in the nature of iron and steel production in China.

  5. Regime shift from phytoplankton to macrophyte dominance in a large river: Top-down versus bottom-up effects

    Energy Technology Data Exchange (ETDEWEB)

    Ibanez, Carles, E-mail: carles.ibanez@irta.cat [IRTA Aquatic Ecosystems, Carretera Poble Nou, Km 5.5, 43540 St. Carles de la Rapita, Catalonia (Spain); Alcaraz, Carles; Caiola, Nuno; Rovira, Albert; Trobajo, Rosa [IRTA Aquatic Ecosystems, Carretera Poble Nou, Km 5.5, 43540 St. Carles de la Rapita, Catalonia (Spain); Alonso, Miguel [United Research Services S.L., Urgell 143, 08036 Barcelona, Catalonia (Spain); Duran, Concha [Confederacion Hidrografica del Ebro, Sagasta 24-26, 50071 Zaragoza, Aragon (Spain); Jimenez, Pere J. [Grup Natura Freixe, Major 56, 43750 Flix, Catalonia (Spain); Munne, Antoni [Agencia Catalana de l' Aigua, Provenca 204-208, 08036 Barcelona, Catalonia (Spain); Prat, Narcis [Departament d' Ecologia, Universitat de Barcelona, Diagonal 645, 08028 Barcelona Catalonia (Spain)

    2012-02-01

    The lower Ebro River (Catalonia, Spain) has recently undergone a regime shift from a phytoplankton-dominated to a macrophyte-dominated system. This shift is well known in shallow lakes but apparently it has never been documented in rivers. Two initial hypotheses to explain the collapse of the phytoplankton were considered: a) the diminution of nutrients (bottom-up); b) the filtering effect due to the colonization of the zebra mussel (top-down). Data on water quality, hydrology and biological communities (phytoplankton, macrophytes and zebra mussel) was obtained both from existing data sets and new surveys. Results clearly indicate that the decrease in phosphorus is the main cause of a dramatic decrease in chlorophyll and large increase in water transparency, triggering the subsequent colonization of macrophytes in the river bed. A Generalized Linear Model analysis showed that the decrease in dissolved phosphorus had a relative importance 14 times higher than the increase in zebra mussel density to explain the variation of total chlorophyll. We suggest that the described changes in the lower Ebro River can be considered a novel ecosystem shift. This shift is triggering remarkable changes in the biological communities beyond the decrease of phytoplankton and the proliferation of macrophytes, such as massive colonization of Simulidae (black fly) and other changes in the benthic invertebrate communities that are currently investigated. - Highlights: Black-Right-Pointing-Pointer We show a regime shift in a large river from phytoplankton to macrophyte dominance. Black-Right-Pointing-Pointer Two main hypotheses are considered: nutrient decrease and zebra mussel grazing. Black-Right-Pointing-Pointer Phosphorus depletion is found to be the main cause of the phytoplankton decline. Black-Right-Pointing-Pointer We conclude that oligotrophication triggered the colonization of macrophytes. Black-Right-Pointing-Pointer This new regime shift in a river is similar to that described

  6. Bottom-up and top-down processes in body representation: a study of brain-damaged and amputee patients.

    Science.gov (United States)

    Palermo, Liana; Di Vita, Antonella; Piccardi, Laura; Traballesi, Marco; Guariglia, Cecilia

    2014-09-01

    Body representation is a complex process involving different sources of top-down and bottom-up information. Processing the position and the relations among different body parts is necessary to build up a specific body representation, that is, the visuospatial body map (or topological map of the body). Here we aimed to investigate how the loss of peripheral or central information affects this representation by testing amputee and brain-damaged patients. Thirty-two unilateral brain-damaged patients (i.e., left-brain-damaged patients and right-brain-damaged patients who were or were not affected by personal neglect), 18 lower limb amputees and 15 healthy controls took part in the study. The topological body map was assessed by means of the "Frontal body-evocation subtest" (Daurat-Hmeljiak, Stambak, & Berges, 1978), in which participants have to put tiles (each representing a body part) on a small wooden board on which a head is depicted. Group statistical analysis showed that in amputee patients the loss of peripheral information about the right lower limb affects the ability to represent relations among different body parts as much as the loss of top-down information in brain-damaged patients with personal neglect. Single case analysis of brain-damaged patients without personal neglect showed that the topological map of the body was deficient in 1 right-brain-damaged and 2 left-brain-damaged patients. Studying amputee and brain-damaged patients together allowed us to highlight the importance of visuospatial information about one's own limbs and the role of both hemispheres (not only the left one) in creating an efficient topological body representation. (c) 2014 APA, all rights reserved.

  7. Assessment of Air Pollutants and Greenhouse Gases Emission Over East Asia : A Bottom-up Inventory Perspective

    Science.gov (United States)

    Woo, J. H.; Kim, Y.; Lee, Y. M.; Choi, K. C.; Zhang, Q.; Kurokawa, J. I.; Lee, J. B.; Song, C. K.; Kim, S.

    2014-12-01

    Air pollutants (SLCPs) such as tropospheric ozone and aerosols are mainly affected by meteorological variables and emissions. East Asia is one of important source regions of both anthropogenic and natural air pollutants and GHGs. Therefore, significant environmental changes are expected in the future and air quality modeling is the important methodology to quantitatively evaluate them. Multiple emission inventories with various spatio-temporal resolutions are necessary in support of many different air quality modeling and future climate chage researches. Many emission inventories have been developed for Asia and for Globe, such as TRACE-P, INTEX, REAS, CREATE, MICS-Asia, HTAP, SRES, RCP. Those inventories have been successfully used for many international researches, but also have several limitations including relatively old base year, limited number of pollutants/types, and low transparency of sector/fuel information. Understanding discrepancies and similarities among those intentories would give us a better insights to understand not only present status regional emissions amounts but structures of society and policy that link to the future emissions. To understand these, we; 1) selected several base-year bottom-up anthropogenic emission inventories over East Asia, 2) inter-compare emission inventories with more comprehensive sector/fuel classification, 3) explorer emissions change with more updated acvities, emission factors, and control options. The tentative results show that more than 50% of emission amount could be differ by inventory selection and more than 30% of emissions could be changed by emissions factor and/or control options. More findings regarding to these objectives will be presented on site

  8. Bottom-up assembly of hydrogels from bacteriophage and Au nanoparticles: the effect of cis- and trans-acting factors.

    Directory of Open Access Journals (Sweden)

    Glauco R Souza

    Full Text Available Hydrogels have become a promising research focus because of their potential for biomedical application. Here we explore the long-range, electrostatic interactions by following the effect of trans-acting (pH and cis-acting factors (peptide mutation on the formation of Au-phage hydrogels. These bioinorganic hydrogels can be generated from the bottom-up assembly of Au nanoparticles (Au NP with either native or mutant bacteriophage (phage through electrostatic interaction of the phage pVIII major capsid proteins (pVIII. The cis-acting factor consists of a peptide extension displayed on the pVIII that mutates the phage. Our results show that pH can dictate the direct-assembly and stability of Au-phage hydrogels in spite of the differences between the native and the mutant pVIII. The first step in characterizing the interactions of Au NP with phage was to generate a molecular model that identified the charge distribution and structure of the native and mutant pVIII. This model indicated that the mutant peptide extension carried a higher positive charge relative to the native pVIII at all pHs. Next, by monitoring the Au-phage interaction by means of optical microscopy, elastic light scattering, fractal dimension analysis as well as Uv-vis and surface plasmon resonance spectroscopy, we show that the positive charge of the mutant peptide extension favors the opposite charge affinity between the phage and Au NP as the pH is decreased. These results show the versatility of this assembly method, where the stability of these hydrogels can be achieved by either adjusting the pH or by changing the composition of the phage pVIII without the need of phage display libraries.

  9. Systematic Correlation Matrix Evaluation (SCoMaE) - a bottom-up, science-led approach to identifying indicators

    Science.gov (United States)

    Mengis, Nadine; Keller, David P.; Oschlies, Andreas

    2018-01-01

    This study introduces the Systematic Correlation Matrix Evaluation (SCoMaE) method, a bottom-up approach which combines expert judgment and statistical information to systematically select transparent, nonredundant indicators for a comprehensive assessment of the state of the Earth system. The methods consists of two basic steps: (1) the calculation of a correlation matrix among variables relevant for a given research question and (2) the systematic evaluation of the matrix, to identify clusters of variables with similar behavior and respective mutually independent indicators. Optional further analysis steps include (3) the interpretation of the identified clusters, enabling a learning effect from the selection of indicators, (4) testing the robustness of identified clusters with respect to changes in forcing or boundary conditions, (5) enabling a comparative assessment of varying scenarios by constructing and evaluating a common correlation matrix, and (6) the inclusion of expert judgment, for example, to prescribe indicators, to allow for considerations other than statistical consistency. The example application of the SCoMaE method to Earth system model output forced by different CO2 emission scenarios reveals the necessity of reevaluating indicators identified in a historical scenario simulation for an accurate assessment of an intermediate-high, as well as a business-as-usual, climate change scenario simulation. This necessity arises from changes in prevailing correlations in the Earth system under varying climate forcing. For a comparative assessment of the three climate change scenarios, we construct and evaluate a common correlation matrix, in which we identify robust correlations between variables across the three considered scenarios.

  10. Bottom-up engineering of biological systems through standard bricks: a modularity study on basic parts and devices.

    Directory of Open Access Journals (Sweden)

    Lorenzo Pasotti

    Full Text Available BACKGROUND: Modularity is a crucial issue in the engineering world, as it enables engineers to achieve predictable outcomes when different components are interconnected. Synthetic Biology aims to apply key concepts of engineering to design and construct new biological systems that exhibit a predictable behaviour. Even if physical and measurement standards have been recently proposed to facilitate the assembly and characterization of biological components, real modularity is still a major research issue. The success of the bottom-up approach strictly depends on the clear definition of the limits in which biological functions can be predictable. RESULTS: The modularity of transcription-based biological components has been investigated in several conditions. First, the activity of a set of promoters was quantified in Escherichia coli via different measurement systems (i.e., different plasmids, reporter genes, ribosome binding sites relative to an in vivo reference promoter. Second, promoter activity variation was measured when two independent gene expression cassettes were assembled in the same system. Third, the interchangeability of input modules (a set of constitutive promoters and two regulated promoters connected to a fixed output device (a logic inverter expressing GFP was evaluated. The three input modules provide tunable transcriptional signals that drive the output device. If modularity persists, identical transcriptional signals trigger identical GFP outputs. To verify this, all the input devices were individually characterized and then the input-output characteristic of the logic inverter was derived in the different configurations. CONCLUSIONS: Promoters activities (referred to a standard promoter can vary when they are measured via different reporter devices (up to 22%, when they are used within a two-expression-cassette system (up to 35% and when they drive another device in a functionally interconnected circuit (up to 44%. This paper

  11. Motivation and drives in bottom-up developments in natural hazards management: multiple-use of adaptation strategies in Austria

    Science.gov (United States)

    Thaler, Thomas; Fuchs, Sven

    2015-04-01

    Losses from extreme hydrological events, such as recently experienced in Europe have focused the attention of policymakers as well as researchers on vulnerability to natural hazards. In parallel, the context of changing flood risks under climate and societal change is driving transformation in the role of the state in responsibility sharing and individual responsibilities for risk management and precaution. The new policy agenda enhances the responsibilities of local authorities and private citizens in hazard management and reduces the role of central governments. Within the objective is to place added responsibility on local organisations and citizens to determine locally-based strategies for risk reduction. A major challenge of modelling adaptation is to represent the complexity of coupled human-environmental systems and particularly the feedback loops between environmental dynamics and human decision-making processes on different scales. This paper focuses on bottom-up initiatives to flood risk management which are, by definition, different from the mainstream. These initiatives are clearly influenced (positively or negatively) by a number of factors, where the combination of these interdependences can create specific conditions that alter the opportunity for effective governance arrangements in a local scheme approach. In total, this study identified six general drivers which encourage the implementation of flood storages, such as direct relation to recent major flood frequency and history, the initiative of individual stakeholders (promoters), political pressures from outside (e.g. business companies, private households) and a strong solidarity attitude of municipalities and the stakeholders involved. Although partnership approach may be seen as an 'optimal' solution for flood risk management, in practice there are many limitations and barriers in establishing these collaborations and making them effective (especially in the long term) with the consequences

  12. Bottom up effects on bacterioplankton growth and composition during summer-autumn transition in the open NW Mediterranean Sea

    Directory of Open Access Journals (Sweden)

    F. Van Wambeke

    2009-04-01

    Full Text Available We examined the vertical and temporal dynamics of nutrients, ectoenzymatic activities under late summer-fall transition period (September–October 2004 in NW Mediterranean Sea in relation to temporal change in factors limiting bacterial production. The depth of the mixed layer (12.8±5.3 m was extremely stable until the onset of the destratification period after 11 October, creating a zone where diffusion of nutrient from the much deeper phosphacline (69±12 m and nitracline (50±8 m was probably strongly limited. However after 1st October, a shallowing of nutriclines occured, particularly marked for nitracline. Hence, the nitrate to phosphate ratio within the mixed layer, although submitted to a high short term variability, shifted the last week of the cruise from 1.1±1.2 to 4.6±3.8, and nitrate increased by a factor 2 (0.092±0.049 μM. A corresponding switch from more than one limitation (PN to P-only limitation of bacterial production was observed during the month as detected by enrichment bioassays. Differences in the identity of the limiting nutrient in surface (5 m: N and P at the beginning, strictly P at the end of the study versus 80 m (labile carbon influence greatly bacterial community structure shift between these two layers. The two communities (5 and 80 m reacted rapidly (24 h to changes in nutrient concentrations by drastic modification of total and active population assemblages resulting in changes in activity. For bacterial production values less than 10 ng C l−1 h−1 (associated to deeper layers, aminopeptidase and lipase exhibited higher activity relative to production whereas phosphatase varied in the same proportions than BP on the range of activities tested. Our results illustrate the effect of bottom-up control on bacterial community structure and activities in the epipelagic NW Mediterranean Sea.

  13. Nitrogen and water inputs to tomato plant do not trigger bottom-up effects on a leafminer parasitoid through host and non-host exposures.

    Science.gov (United States)

    Dong, Yong-Cheng; Han, Peng; Niu, Chang-Ying; Zappalà, Lucia; Amiens-Desneux, Edwige; Bearez, Philippe; Lavoir, Anne-Violette; Biondi, Antonio; Desneux, Nicolas

    2017-10-02

    Bottom-up and top-down forces are major components of biological control against pests in an agro-ecosystem. Understanding the multi-trophic interactions between plants and secondary consumers would help optimize pest control strategies. We manipulated nitrogen and/or water inputs to tomato plants (Solanum lycopersicum) to test whether these manipulations could trigger bottom-up effects on the parasitoid Necremnus tutae via host (Tuta absoluta) and/or non-host (Bemisia tabaci) exposures, and compared the control efficacy of N. tutae on T. absoluta in the presence and absence of B. tabaci. The results showed no cascading effects of plant nitrogen and/or water inputs on N. tutae via either host or non-host exposure. The bottom-up force was mitigated by chewing or sap-feeding insect consumers at the second energy level. By contrast, the top-down force on T. absoluta from parasitoids was enhanced by an additionally provided non-host, which could produce alternative food sources extending N. tutae longevity and enhancing the fitness of its offspring. Our results provided evidence for the combination of bottom-up and top-down approaches in tomato integrated pest management programs. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

  14. The changing contribution of top-down and bottom-up limitation of mesopredators during 220 years of land use and climate change

    NARCIS (Netherlands)

    Pasanen-Mortensen, Marianne; Elmhagen, Bodil; Lindén, Harto; Bergström, Roger; Wallgren, Märtha; van der Velde, Ype; Cousins, Sara A.O.

    2017-01-01

    Apex predators may buffer bottom-up driven ecosystem change, as top-down suppression may dampen herbivore and mesopredator responses to increased resource availability. However, theory suggests that for this buffering capacity to be realized, the equilibrium abundance of apex predators must

  15. Closing the gap? Top-down versus bottom-up projections of China's regional energy use and CO2 emissions

    DEFF Research Database (Denmark)

    Dai, Hancheng; Mischke, Peggy; Xie, Xuxuan

    2016-01-01

    As the world's largest CO2 emitter, China is a prominent case study for scenario analysis. This study uses two newly developed global top-down and bottom-up models with a regional China focus to compare China's future energy and CO2 emission pathways toward 2050. By harmonizing the economic and d...

  16. Applying bottom-up material flow analysis to identify the system boundaries of non-energy use data in international energy statistics

    NARCIS (Netherlands)

    Weiss, M.|info:eu-repo/dai/nl/156419912; Neelis, M.L.|info:eu-repo/dai/nl/249570173; Zuidberg, M.C.; Patel, M.K.|info:eu-repo/dai/nl/18988097X

    2008-01-01

    Data on the non-energy use of fossil fuels in energy statistics are subject to major uncertainties. We apply a simple bottom-up methodology to recalculate non-energy use for the entire world and for the 50 countries with the highest consumption of fossil fuels for non-energy purposes. We quantify

  17. Bottom-up effects on biomass versus top-down effects on identity: a multiple-lake fish community manipulation experiment

    NARCIS (Netherlands)

    Lemmens, P.; Declerck, S.A.J.; Tuytens, K.; Vanderstukken, M.; De Meester, L.

    2018-01-01

    The extent to which ecosystems are regulated by top-down relative to bottom-up control has been a dominant paradigm in ecology for many decades. For lakes, it has been shown that predation by fish is an important determinant of variation in zooplankton and phytoplankton community characteristics.

  18. Bottom-Up Mechanisms Are Involved in the Relation between Accuracy in Timing Tasks and Intelligence--Further Evidence Using Manipulations of State Motivation

    Science.gov (United States)

    Ullen, Fredrik; Soderlund, Therese; Kaaria, Lenita; Madison, Guy

    2012-01-01

    Intelligence correlates with accuracy in various timing tasks. Such correlations could be due to both bottom-up mechanisms, e.g. neural properties that influence both temporal accuracy and cognitive processing, and differences in top-down control. We have investigated the timing-intelligence relation using a simple temporal motor task, isochronous…

  19. The changing contribution of top-down and bottom-up limitation of mesopredators during 220 years of land use and climate change.

    Science.gov (United States)

    Pasanen-Mortensen, Marianne; Elmhagen, Bodil; Lindén, Harto; Bergström, Roger; Wallgren, Märtha; van der Velde, Ype; Cousins, Sara A O

    2017-05-01

    Apex predators may buffer bottom-up driven ecosystem change, as top-down suppression may dampen herbivore and mesopredator responses to increased resource availability. However, theory suggests that for this buffering capacity to be realized, the equilibrium abundance of apex predators must increase. This raises the question: will apex predators maintain herbivore/mesopredator limitation, if bottom-up change relaxes resource constraints? Here, we explore changes in mesopredator (red fox Vulpes vulpes) abundance over 220 years in response to eradication and recovery of an apex predator (Eurasian lynx Lynx lynx), and changes in land use and climate which are linked to resource availability. A three-step approach was used. First, recent data from Finland and Sweden were modelled to estimate linear effects of lynx density, land use and winter temperature on fox density. Second, lynx density, land use and winter temperature was estimated in a 22 650 km2 focal area in boreal and boreo-nemoral Sweden in the years 1830, 1920, 2010 and 2050. Third, the models and estimates were used to project historic and future fox densities in the focal area. Projected fox density was lowest in 1830 when lynx density was high, winters cold and the proportion of cropland low. Fox density peaked in 1920 due to lynx eradication, a mesopredator release boosted by favourable bottom-up changes - milder winters and cropland expansion. By 2010, lynx recolonization had reduced fox density, but it remained higher than in 1830, partly due to the bottom-up changes. Comparing 1830 to 2010, the contribution of top-down limitation decreased, while environment enrichment relaxed bottom-up limitation. Future scenarios indicated that by 2050, lynx density would have to increase by 79% to compensate for a projected climate-driven increase in fox density. We highlight that although top-down limitation in theory can buffer bottom-up change, this requires compensatory changes in apex predator abundance

  20. Abundant Lysine Methylation and N-Terminal Acetylation in Sulfolobus islandicus Revealed by Bottom-Up and Top-Down Proteomics*

    Science.gov (United States)

    Vorontsov, Egor A.; Rensen, Elena; Prangishvili, David; Krupovic, Mart; Chamot-Rooke, Julia

    2016-01-01

    Protein post-translational methylation has been reported to occur in archaea, including members of the genus Sulfolobus, but has never been characterized on a proteome-wide scale. Among important Sulfolobus proteins carrying such modification are the chromatin proteins that have been described to be methylated on lysine side chains, resembling eukaryotic histones in that aspect. To get more insight into the extent of this modification and its dynamics during the different growth steps of the thermoacidophylic archaeon S. islandicus LAL14/1, we performed a global and deep proteomic analysis using a combination of high-throughput bottom-up and top-down approaches on a single high-resolution mass spectrometer. 1,931 methylation sites on 751 proteins were found by the bottom-up analysis, with methylation sites on 526 proteins monitored throughout three cell culture growth stages: early-exponential, mid-exponential, and stationary. The top-down analysis revealed 3,978 proteoforms arising from 681 proteins, including 292 methylated proteoforms, 85 of which were comprehensively characterized. Methylated proteoforms of the five chromatin proteins (Alba1, Alba2, Cren7, Sul7d1, Sul7d2) were fully characterized by a combination of bottom-up and top-down data. The top-down analysis also revealed an increase of methylation during cell growth for two chromatin proteins, which had not been evidenced by bottom-up. These results shed new light on the ubiquitous lysine methylation throughout the S. islandicus proteome. Furthermore, we found that S. islandicus proteins are frequently acetylated at the N terminus, following the removal of the N-terminal methionine. This study highlights the great value of combining bottom-up and top-down proteomics for obtaining an unprecedented level of accuracy in detecting differentially modified intact proteoforms. The data have been deposited to the ProteomeXchange with identifiers PXD003074 and PXD004179. PMID:27555370

  1. Research on ethics in two large Human Biomonitoring projects ECNIS and NewGeneris: a bottom up approach

    Directory of Open Access Journals (Sweden)

    Casteleyn Ludwine

    2008-01-01

    Full Text Available Abstract Assessment of ethical aspects and authorization by ethics committees have become a major constraint for health research including human subjects. Ethical reference values often are extrapolated from clinical settings, where emphasis lies on decisional autonomy and protection of individual's privacy. The question rises if this set of values used in clinical research can be considered as relevant references for HBM research, which is at the basis of public health surveillance. Current and future research activities using human biomarkers are facing new challenges and expectancies on sensitive socio-ethical issues. Reflection is needed on the necessity to balance individual rights against public interest. In addition, many HBM research programs require international collaboration. Domestic legislation is not always easily applicable in international projects. Also, there seem to be considerable inconsistencies in ethical assessments of similar research activities between different countries and even within one country. All this is causing delay and putting the researcher in situations in which it is unclear how to act in accordance with necessary legal requirements. Therefore, analysis of ethical practices and their consequences for HBM research is needed. This analysis will be performed by a bottom-up approach, based on a methodology for comparative analysis of determinants in ethical reasoning, allowing taking into account different social, cultural, political and historical traditions, in view of safeguarding common EU values. Based on information collected in real life complexity, paradigm cases and virtual case scenarios will be developed and discussed with relevant stakeholders to openly discuss possible obstacles and to identify options for improvement in regulation. The material collected will allow developing an ethical framework which may constitute the basis for a more harmonized and consistent socio-ethical and legal approach

  2. Assisted editing od SensorML with EDI. A bottom-up scenario towards the definition of sensor profiles.

    Science.gov (United States)

    Oggioni, Alessandro; Tagliolato, Paolo; Fugazza, Cristiano; Bastianini, Mauro; Pavesi, Fabio; Pepe, Monica; Menegon, Stefano; Basoni, Anna; Carrara, Paola

    2015-04-01

    -product of this ongoing work is currently constituting an archive of predefined sensor descriptions. This information is being collected in order to further ease metadata creation in the next phase of the project. Users will be able to choose among a number of sensor and sensor platform prototypes: These will be specific instances on which it will be possible to define, in a bottom-up approach, "sensor profiles". We report on the outcome of this activity.

  3. Isocentric color saliency in images

    NARCIS (Netherlands)

    Valenti, R.; Sebe, N.; Gevers, T.

    2009-01-01

    In this paper we propose a novel computational method to infer visual saliency in images. The computational method is based on the idea that salient objects should have local characteristics that are different than the rest of the scene, being edges, color or shape, and that these characteristics

  4. Planktonic heterotrophic nanoflagellate abundance along a trophic gradient in subtropical reservoirs: influence of a bottom-up or top-down control mechanism

    Directory of Open Access Journals (Sweden)

    Danielle Goeldner Pereira

    2014-05-01

    Full Text Available The aim of the current study was to assess the variability in heterotrophic nanoflagellate abundance attributable to variables responsible for the influence of bottom-up and top-down control mechanisms in the plankton food web along a trophic gradient in subtropical reservoirs (Paraná State,Brazil. In particular, we hypothesised that food resources were the main determinant for the abundance of heterotrophic nanoflagellates (HNF along a trophic gradient. Results showed that HNF communities were weakly influenced by the bottom-up mechanism. Moreover, there was evidence of a slight influence from a top-down control mechanism on this community. Therefore, the results of the present study did not corroborate the hypothesis initially proposed, and further studies are needed to elucidate the complex outcomes of trophic gradients on planktonic HNF communities, including other predictor variables related to abiotic interactions, such as morphometrics, hydrology, priorities uses and climate conditions

  5. Bringing together models from bottom-up and top-down approaches: an application for growth of Escherichia coli on different carbohydrates.

    Science.gov (United States)

    Kremling, Andeas

    2012-01-01

    Modeling in systems biology follows two lines: a data driven top-down approach that integrates experimental data from various "omics" technologies and a model based bottom-up approach where the model structure is given and kinetic parameters are chosen in such a way that an experimental observation can be reproduced quantitatively or qualitatively. Mathematical models are frequently used to elucidate cellular design principles in order to understand complex biochemical networks better. To show that both approaches lead to a consistent description of cellular dynamics, mathematical models from both approaches are explored. On the level of transcription factor activities a sufficient qualitative agreement is observed. Experimental data for the classical growth experiment of Escherichia coli on two carbon sources, glucose and lactose is available to set up the data driven model and to support the theoretical findings from the bottom-up approach.

  6. Top-down and bottom-up lipidomic analysis of rabbit lipoproteins under different metabolic conditions using flow field-flow fractionation, nanoflow liquid chromatography and mass spectrometry.

    Science.gov (United States)

    Byeon, Seul Kee; Kim, Jin Yong; Lee, Ju Yong; Chung, Bong Chul; Seo, Hong Seog; Moon, Myeong Hee

    2015-07-31

    This study demonstrated the performances of top-down and bottom-up approaches in lipidomic analysis of lipoproteins from rabbits raised under different metabolic conditions: healthy controls, carrageenan-induced inflammation, dehydration, high cholesterol (HC) diet, and highest cholesterol diet with inflammation (HCI). In the bottom-up approach, the high density lipoproteins (HDL) and the low density lipoproteins (LDL) were size-sorted and collected on a semi-preparative scale using a multiplexed hollow fiber flow field-flow fractionation (MxHF5), followed by nanoflow liquid chromatography-ESI-MS/MS (nLC-ESI-MS/MS) analysis of the lipids extracted from each lipoprotein fraction. In the top-down method, size-fractionated lipoproteins were directly infused to MS for quantitative analysis of targeted lipids using chip-type asymmetrical flow field-flow fractionation-electrospray ionization-tandem mass spectrometry (cAF4-ESI-MS/MS) in selected reaction monitoring (SRM) mode. The comprehensive bottom-up analysis yielded 122 and 104 lipids from HDL and LDL, respectively. Rabbits within the HC and HCI groups had lipid patterns that contrasted most substantially from those of controls, suggesting that HC diet significantly alters the lipid composition of lipoproteins. Among the identified lipids, 20 lipid species that exhibited large differences (>10-fold) were selected as targets for the top-down quantitative analysis in order to compare the results with those from the bottom-up method. Statistical comparison of the results from the two methods revealed that the results were not significantly different for most of the selected species, except for those species with only small differences in concentration between groups. The current study demonstrated that top-down lipid analysis using cAF4-ESI-MS/MS is a powerful high-speed analytical platform for targeted lipidomic analysis that does not require the extraction of lipids from blood samples. Copyright © 2015 Elsevier B

  7. Disentangling the Role of Cortico-Basal Ganglia Loops in Top-Down and Bottom-Up Visual Attention: An Investigation of Attention Deficits in Parkinson Disease.

    Science.gov (United States)

    Tommasi, Giorgio; Fiorio, Mirta; Yelnik, Jérôme; Krack, Paul; Sala, Francesca; Schmitt, Emmanuelle; Fraix, Valérie; Bertolasi, Laura; Le Bas, Jean-François; Ricciardi, Giuseppe Kenneth; Fiaschi, Antonio; Theeuwes, Jan; Pollak, Pierre; Chelazzi, Leonardo

    2015-06-01

    It is solidly established that top-down (goal-driven) and bottom-up (stimulus-driven) attention mechanisms depend on distributed cortical networks, including prefrontal and frontoparietal regions. On the other hand, it is less clear whether the BG also contribute to one or the other of these mechanisms, or to both. The current study was principally undertaken to clarify this issue. Parkinson disease (PD), a neurodegenerative disorder primarily affecting the BG, has proven to be an effective model for investigating the contribution of the BG to different brain functions; therefore, we set out to investigate deficits of top-down and bottom-up attention in a selected cohort of PD patients. With this objective in mind, we compared the performance on three computerized tasks of two groups of 12 parkinsonian patients (assessed without any treatment), one otherwise pharmacologically treated and the other also surgically treated, with that of a group of controls. The main behavioral tool for our study was an attentional capture task, which enabled us to tap the competition between top-down and bottom-up mechanisms of visual attention. This task was suitably combined with a choice RT and a simple RT task to isolate any specific deficit of attention from deficits in motor response selection and initiation. In the two groups of patients, we found an equivalent increase of attentional capture but also comparable delays in target selection in the absence of any salient distractor (reflecting impaired top-down mechanisms) and movement initiation compared with controls. In contrast, motor response selection processes appeared to be prolonged only in the operated patients. Our results confirm that the BG are involved in both motor and cognitive domains. Specifically, damage to the BG, as it occurs in PD, leads to a distinct deficit of top-down control of visual attention, and this can account, albeit indirectly, for the enhancement of attentional capture, reflecting weakened

  8. Bottom-up and top-down controls on coral reef sponges: disentangling within-habitat and between-habitat processes.

    Science.gov (United States)

    Wulff, Janie

    2017-04-01

    Polarized debates about top-down vs. bottom-up control have given way to more nuanced understanding of control by both resources and consumers in many systems, but coral reef sponges have recently been asserted to differ from other groups in being controlled exclusively top-down. This assertion has been countered by reports of exclusively bottom-up control, with both conclusions based on studies of the same species. Accelerating deterioration of coral reefs motivates knowing the contexts in which either consumers or nutrients or both control key ecosystem role players like sponges. Accordingly, genotype- and size-controlled individuals of 12 common Caribbean reef sponge species were transplanted, in the field, into five circumstances differing in predators, competitors, and the picoplankton consumed by sponges. Growth and survival of the experimental transplants for periods of 1-9 yr revealed context-dependent control of sponges. Primary control of growth was bottom-up, with more picoplankton resulting in consistent and sustained higher growth rates for all 12 of these ecologically and phylogenetically diverse species. Top-down control was not detected within-habitat, on the coral reef. However, between-habitat control was by predation and competition, with reef sponges excluded from adjacent seagrass meadows by spongivorous starfish, and excluded from mangrove prop roots by faster-growing mangrove sponges. These results highlight the strong importance of experimental design details that consider behavior idiosyncrasies, sufficiently long time scales, and appropriate division of species into categories. Diametrically opposite results from studies of the same species also illustrate the inherently greater difficulty of detecting bottom-up processes and the importance of distinguishing within-habitat vs. between-habitat patterns and processes. © 2017 by the Ecological Society of America.

  9. Developmental changes in natural viewing behavior: bottom-up and top-down differences between children, young adults and older adults

    Directory of Open Access Journals (Sweden)

    Alper eAçık

    2010-11-01

    Full Text Available Despite the growing interest in fixation selection under natural conditions, there is a major gap in the literature concerning its developmental aspects. Early in life, bottom-up processes, such as local image feature – color, luminance contrast etc. - guided viewing, might be more prominent but later overshadowed by more top-down processing. Moreover, with decline in visual functioning in old age, the bottom-up processing is known to suffer. Here we recorded the eye-movements of 7-9 year-old children, 19-27 year-old adults and older adults above 72 years of age while they viewed natural and complex images before performing a patch recognition task. Task performance displayed the classical inverted U-shape, with young adults outperforming the other age groups. Fixation discrimination performance of local feature values dropped with age. Whereas children display the highest feature values at fixated points, suggesting a bottom-up mechanism, older adult viewing behavior is less feature-dependent, reminiscent of a top-down strategy. Importantly, we observed a double dissociation between children and elderly regarding the effects of active viewing on feature-related viewing: Explorativeness correlates with feature-related viewing negatively in young age, and positively in the case of older adults. The results indicate that, with age, bottom-up fixation selection loses strength and/or the role of top-down processes becomes more important. Older adults who increase their feature-related viewing by being more explorative make use of this low-level information and perform better in the task. The present study thus reveals an important developmental change in natural and task-guided viewing.

  10. EP5 Mining Bottom-Up and Top-Down Datasets for Predictable and not so Predictable Post-Translational Modifications.

    OpenAIRE

    Whitelegge, J; Cournoyer, J.; Pevzner, P.

    2007-01-01

    Post-translational modifications (PTMs) can be routinely located and characterized by tandem mass spectrometry, provided the researchers know the identity and mass of the modification they are looking for. In the spirit of discovery proteomics, it is desirable that both bottom-up and top-down datasets be screened for all possible chemical modifications, in order to avoid bias toward the known. Analysis of saliva proteins from a number of human subjects is starting to reveal significant divers...

  11. Modeling Technical Change in Energy System Analysis: Analyzing the Introduction of Learning-by-Doing in Bottom-up Energy Models

    Energy Technology Data Exchange (ETDEWEB)

    Berglund, Christer; Soederholm, Patrik [Luleaa Univ. of Technology (Sweden). Div. of Economics

    2005-02-01

    The main objective of this paper is to provide an overview and a critical analysis of the recent literature on incorporating induced technical change in energy systems models. Special emphasis is put on surveying recent studies aiming at integrating learning-by-doing into bottom-up energy systems models through so-called learning curves, and on analyzing the relevance of learning curve analysis for understanding the process of innovation and technology diffusion in the energy sector. The survey indicates that this model work represents a major advance in energy research, and embeds important policy implications, not the least concerning the cost and the timing of environmental policies (including carbon emission constraints). However, bottom-up energy models with endogenous learning are also limited in their characterization of technology diffusion and innovation. While they provide a detailed account of technical options - which is absent in many top-down models - they also lack important aspects of diffusion behavior that are captured in top-down representations. For instance, they fail in capturing strategic technology diffusion behavior in the energy sector, and they neglect important general equilibrium impacts (such as the opportunity cost of redirecting R and D support to the energy sector). For these reasons bottom-up and top-down models with induced technical change should not be viewed as substitutes but rather as complements.

  12. Abundant Lysine Methylation and N-Terminal Acetylation in Sulfolobus islandicus Revealed by Bottom-Up and Top-Down Proteomics.

    Science.gov (United States)

    Vorontsov, Egor A; Rensen, Elena; Prangishvili, David; Krupovic, Mart; Chamot-Rooke, Julia

    2016-11-01

    Protein post-translational methylation has been reported to occur in archaea, including members of the genus Sulfolobus, but has never been characterized on a proteome-wide scale. Among important Sulfolobus proteins carrying such modification are the chromatin proteins that have been described to be methylated on lysine side chains, resembling eukaryotic histones in that aspect. To get more insight into the extent of this modification and its dynamics during the different growth steps of the thermoacidophylic archaeon S. islandicus LAL14/1, we performed a global and deep proteomic analysis using a combination of high-throughput bottom-up and top-down approaches on a single high-resolution mass spectrometer. 1,931 methylation sites on 751 proteins were found by the bottom-up analysis, with methylation sites on 526 proteins monitored throughout three cell culture growth stages: early-exponential, mid-exponential, and stationary. The top-down analysis revealed 3,978 proteoforms arising from 681 proteins, including 292 methylated proteoforms, 85 of which were comprehensively characterized. Methylated proteoforms of the five chromatin proteins (Alba1, Alba2, Cren7, Sul7d1, Sul7d2) were fully characterized by a combination of bottom-up and top-down data. The top-down analysis also revealed an increase of methylation during cell growth for two chromatin proteins, which had not been evidenced by bottom-up. These results shed new light on the ubiquitous lysine methylation throughout the S. islandicus proteome. Furthermore, we found that S. islandicus proteins are frequently acetylated at the N terminus, following the removal of the N-terminal methionine. This study highlights the great value of combining bottom-up and top-down proteomics for obtaining an unprecedented level of accuracy in detecting differentially modified intact proteoforms. The data have been deposited to the ProteomeXchange with identifiers PXD003074 and PXD004179. © 2016 by The American Society for

  13. Defocus cue and saliency preserving video compression

    Science.gov (United States)

    Khanna, Meera Thapar; Chaudhury, Santanu; Lall, Brejesh

    2016-11-01

    There are monocular depth cues present in images or videos that aid in depth perception in two-dimensional images or videos. Our objective is to preserve the defocus depth cue present in the videos along with the salient regions during compression application. A method is provided for opportunistic bit allocation during the video compression using visual saliency information comprising both the image features, such as color and contrast, and the defocus-based depth cue. The method is divided into two steps: saliency computation followed by compression. A nonlinear method is used to combine pure and defocus saliency maps to form the final saliency map. Then quantization values are assigned on the basis of these saliency values over a frame. The experimental results show that the proposed scheme yields good results over standard H.264 compression as well as pure and defocus saliency methods.

  14. Factors influencing the motivational salience of faces

    OpenAIRE

    Hahn, Amanda C.

    2013-01-01

    My research utilizes a behavioral key-press task adapted from the classic bar-press technique employed in many rodent studies of reward to explore the incentive salience of beauty among humans. In Chapter 2, I replicate previous findings indicating that gender differences exist for the incentive salience of beauty. I extend past findings with regard to the incentive salience of heterosexual beauty by investigating the role of additional aspects of facial appearance. Here, I find that ap...

  15. Exploring the Life Expectancy Increase in Poland in the Context of CVD Mortality Fall: The Risk Assessment Bottom-Up Approach, From Health Outcome to Policies.

    Science.gov (United States)

    Kobza, Joanna; Geremek, Mariusz

    2015-01-01

    Life expectancy at birth is considered the best mortality-based summary indicator of the health status of the population and is useful for measuring long-term health changes. The objective of this article was to present the concept of the bottom-up policy risk assessment approach, developed to identify challenges involved in analyzing risk factor reduction policies and in assessing how the related health indicators have changed over time. This article focuses on the reasons of the significant life expectancy prolongation in Poland over the past 2 decades, thus includes policy context. The methodology details a bottom-up risk assessment approach, a chain of relations between the health outcome, risk factors, and health policy, based on Risk Assessment From Policy to Impact Dimension project guidance. A decline in cardiovascular disease mortality was a key factor that followed life expectancy prolongation. Among basic factors, tobacco and alcohol consumption, diet, physical activity, and new treatment technologies were identified. Poor health outcomes of the Polish population at the beginning of 1990s highlighted the need of the implementation of various health promotion programs, legal acts, and more effective public health policies. Evidence-based public health policy needs translating scientific research into policy and practice. The bottom-up case study template can be one of the focal tools in this process. Accountability for the health impact of policies and programs and legitimization of the decisions of policy makers has become one of the key questions nowadays in European countries' decision-making process and in EU public health strategy. © The Author(s) 2015.

  16. Age-Related Inter-region EEG Coupling Changes during the Control of Bottom-up and Top-down Attention

    Directory of Open Access Journals (Sweden)

    Ling eLi

    2015-12-01

    Full Text Available We investigated age-related changes in electroencephalographic (EEG coupling of theta-, alpha-, and beta-frequency bands during bottom-up and top-down attention. Arrays were presented with either automatic pop-out (bottom-up or effortful search (top-down behavior to younger and older participants. The phase-locking value (PLV was used to estimate coupling strength between scalp recordings. Behavioral performance decreased with age, with a greater age-related decline in accuracy for the search than for the pop-out condition. Aging was associated with a declined coupling strength of theta and alpha frequency bands, with a greater age-related decline in whole-brain coupling values for the search than for the pop-out condition. Specifically, prefronto-frontal coupling in theta- and alpha-bands, fronto-parietal and parieto-occipital couplings in beta-band for younger group showed a right hemispheric dominance, which was reduced with aging to compensate for the inhibitory dysfunction. While pop-out target detection was mainly associated with greater parieto-occipital beta-coupling strength compared to search condition regardless of aging. Furthermore, prefronto-frontal coupling in theta-, alpha- and beta-bands, and parieto-occipital coupling in beta-band functioned as predictors of behavior for both groups. Taken together these findings provide evidence that prefronto-frontal coupling of theta-, alpha-, and beta-bands may serve as a possible basis of aging during visual attention, while parieto-occipital coupling in beta-band could serve for a bottom-up function and be vulnerable to top-down attention control for younger and older groups.

  17. Tax Salience, Voting, and Deliberation

    DEFF Research Database (Denmark)

    Sausgruber, Rupert; Tyran, Jean-Robert

    Tax incentives can be more or less salient, i.e. noticeable or cognitively easy to process. Our hypothesis is that taxes on consumers are more salient to consumers than equivalent taxes on sellers because consumers underestimate the extent of tax shifting in the market. We show that tax salience...... biases consumers' voting on tax regimes, and that experience is an effective de-biasing mechanism in the experimental laboratory. Pre-vote deliberation makes initially held opinions more extreme rather than correct and does not eliminate the bias in the typical committee. Yet, if voters can discuss...... their experience with the tax regimes they are less likely to be biased....

  18. Is top-down vs bottom-up radiological evaluation after febrile urinary tract infection really less stressful for the child and family? Challenging the dogma.

    Science.gov (United States)

    Telli, Onur; Mermerkaya, Murat; Hajiyev, Perviz; Aydogdu, Ozgu; Afandiyev, Faraj; Suer, Evren; Soygur, Tarkan; Burgu, Berk

    2015-03-01

    We evaluated whether stress levels in children and parents during radiological evaluation after febrile urinary tract infection are really lower using the top-down approach, where (99m)technetium dimercaptosuccinic acid renal scintigraphy is used initially, than the bottom-up approach, where voiding cystourethrography is initially performed and repeated examinations are easier for all. We prospectively evaluated 120 children 3 to 8 years old. Pain ratings were obtained using the Faces Pain Scale-Revised, and conversation during the procedure was evaluated using the Child-Adult Medical Procedure Interaction Scale-Revised by 2 independent observers. To evaluate parental anxiety, the State-Trait Anxiety Inventory form was also completed. Following a documented febrile urinary tract infection children were randomized to the top-down or bottom-up group. A third group of 44 children undergoing repeat voiding cystourethrography and their parents were also evaluated. Child ratings of pain using the Faces Pain Scale-Revised were not significantly different between the top-down group following (99m)technetium dimercaptosuccinic acid renal scintigraphy (2.99 on a scale of 10) and the bottom-up group following voiding cystourethrography (3.21). Also the Faces Pain Scale-Revised was not significantly different in the repeat voiding cystourethrography group (3.35). On the Child-Adult Medical Procedure Interaction Scale-Revised there was negative correlation between child coping and child distress, as well as rate of child distress and adult coping promoting behavior. Parental state anxiety scores were significantly less in the top-down and repeat voiding cystourethrography groups than in the bottom-up group. Although the top-down approach and repeat voiding cystourethrography cause less anxiety for caregivers, these values do not correlate to pain scale in children. This finding might be due to lack of appropriate evaluation tools of pediatric pain and anxiety. However, the

  19. The baseline in bottom-up energy efficiency and saving calculations - A concept for its formalisation and a discussion of relevant options

    Energy Technology Data Exchange (ETDEWEB)

    Reichl, Johannes [The Energy Institute at the Johannes Kepler University Linz, Altenberger Strasse 69, 4040 Linz (Austria); Energy efficiency and saving calculations of the European Committee for Standardisation (Austria); Kollmann, Andrea [The Energy Institute at the Johannes Kepler University Linz, Altenberger Strasse 69, 4040 Linz (Austria)

    2011-02-15

    One of the central variables in bottom-up energy efficiency and saving calculations is the energy consumption baseline. In the evaluation of energy efficiency measures, developing this baseline is a challenging task, which may involve serious problems, especially if the energy service of the analysed subject has changed while the energy efficiency measure was being implemented. In this paper we present a formalised concept of the process of developing the baseline that is flexible enough to deal with various difficulties, such as changes in the levels of the energy services involved. We also discuss the most relevant options for deriving the necessary variables. (author)

  20. Objective correlates of pitch salience using pupillometry

    DEFF Research Database (Denmark)

    Bianchi, Federica; Santurette, Sébastien; Wendt, Dorothea

    2014-01-01

    Although objective correlates of pitch salience have been investigated in several neuroimaging studies, the results remain controversial. In the present study, a novel approach to objectively estimate pitch salience was used. Pupil dilation was measured as an indicator of the required effort in p...

  1. Phytoplasma infection of a tropical root crop triggers bottom-up cascades by favoring generalist over specialist herbivores.

    Directory of Open Access Journals (Sweden)

    Kris A G Wyckhuys

    Full Text Available Global interest on plant-microbe-insect interactions is rapidly growing, revealing the multiple ways in which microorganisms mediate plant-herbivore interactions. Phytopathogens regularly alter whole repertoires of plant phenotypic traits, and bring about shifts in key chemical or morphological characteristics of plant hosts. Pathogens can also cause cascading effects on higher trophic levels, and eventually shape entire plant-associated arthropod communities. We tested the hypothesis that a Candidatus Phytoplasma causing cassava witches' broom (CWB on cassava (Manihot esculenta Grantz is altering species composition of invasive herbivores and their associated parasitic hymenopterans. We conducted observational studies in cassava fields in eastern Cambodia to assess the effect of CWB infection on abundance of specialist and generalist mealybugs (Homoptera: Pseudococcidae, and associated primary and hyper-parasitoid species. CWB infection positively affects overall mealybug abundance and species richness at a plant- and field-level, and disproportionately favors a generalist mealybug over a specialist feeder. CWB phytoplasma infection led to increased parasitoid richness and diversity, with richness of 'comparative' specialist taxa being the most significantly affected. Parasitism rate did not differ among infected and uninfected plants, and mealybug host suppression was not impacted. CWB phytoplasma modifies host plant quality for sap-feeding homopterans, differentially affects success rates of two invasive species, and generates niche opportunities for higher trophic orders. By doing so, a Candidatus phytoplasma affects broader food web structure and functioning, and assumes the role of an ecosystem engineer. Our work unveils key facets of phytoplasma ecology, and sheds light upon complex multi-trophic interactions mediated by an emerging phytopathogen. These findings have further implications for invasion ecology and management.

  2. Phytoplasma infection of a tropical root crop triggers bottom-up cascades by favoring generalist over specialist herbivores

    Science.gov (United States)

    Graziosi, Ignazio; Burra, Dharani Dhar; Walter, Abigail Jan

    2017-01-01

    Global interest on plant-microbe-insect interactions is rapidly growing, revealing the multiple ways in which microorganisms mediate plant-herbivore interactions. Phytopathogens regularly alter whole repertoires of plant phenotypic traits, and bring about shifts in key chemical or morphological characteristics of plant hosts. Pathogens can also cause cascading effects on higher trophic levels, and eventually shape entire plant-associated arthropod communities. We tested the hypothesis that a Candidatus Phytoplasma causing cassava witches’ broom (CWB) on cassava (Manihot esculenta Grantz) is altering species composition of invasive herbivores and their associated parasitic hymenopterans. We conducted observational studies in cassava fields in eastern Cambodia to assess the effect of CWB infection on abundance of specialist and generalist mealybugs (Homoptera: Pseudococcidae), and associated primary and hyper-parasitoid species. CWB infection positively affects overall mealybug abundance and species richness at a plant- and field-level, and disproportionately favors a generalist mealybug over a specialist feeder. CWB phytoplasma infection led to increased parasitoid richness and diversity, with richness of ‘comparative’ specialist taxa being the most significantly affected. Parasitism rate did not differ among infected and uninfected plants, and mealybug host suppression was not impacted. CWB phytoplasma modifies host plant quality for sap-feeding homopterans, differentially affects success rates of two invasive species, and generates niche opportunities for higher trophic orders. By doing so, a Candidatus phytoplasma affects broader food web structure and functioning, and assumes the role of an ecosystem engineer. Our work unveils key facets of phytoplasma ecology, and sheds light upon complex multi-trophic interactions mediated by an emerging phytopathogen. These findings have further implications for invasion ecology and management. PMID:28813469

  3. Image structure-based saliency detection

    Science.gov (United States)

    Hong, Jing; Chen, Yufei; Liu, Xianhui; Zhao, Weidong; Jia, Ning; Zhou, Qiangqiang

    2017-07-01

    We consider image intrinsic structure in two aspects: foreground saliency computation and background saliency calculation. On the one hand, a segmented image is represented as a weighted undirected graph, and we calculate the foreground saliency by choosing some superpixels as ranking queries, where we apply a robust background measure to select those for accuracy. On the other hand, we compute the posterior probabilities to measure the background saliency and in terms of the probability, we construct a probability tree via multimerging on superpixels, and then apply the optimization strategy to the background saliency. We evaluate our proposed algorithm on two benchmark datasets and our algorithm yields the competitive results when compared with nine state-of-the-art algorithms in terms of five evaluation metrics.

  4. Framing Extreme Event Attribution from the Bottom up - an Enquiry into the Social Representations of key stakeholders, of the Press and of Climate Scientists.

    Science.gov (United States)

    Vanderlinden, J. P.; Fellmer, M.; Capellini, N.; Meinke, I.; Remvikos, Y.; Bray, D.; Pacteau, C.; Von Storch, H.

    2014-12-01

    Attribution of extreme weather events has recently generated a lot of interest simultaneously within the general public, the scientific community, and stakeholders affected by meteorological extremes. This interest calls for the need to explore the potential convergence of the current atttribution science with the desire and needs of stakeholders. Such an euiry contributes to the development of climate services aiming at quantifying the human responsibility for particular events. Through interviews with climate scientists, through the analysis of the press coverage of extreme meteorological events, and through stakeholder (private sector, covernment services and local and regional government) focus groups, we analyze how social representations of the concepts associated with extreme event attribution are theorized. From the corpuses generated in the course of this enquiry, we build up a grounded, bottom-up, theorization of extreme weather event attribution. This bottom-up theorization allows for a framing of the potential climate services in a way that is attuned to the needs and expectations of the stakeholders. From apparently simple formulations: "what is an extreme event?", "what makes it extreme?", "what is meant by attribution of extreme weather events?", "what do we want to attribute?", "what is a climate service?", we demonstrate the polysemy of these terms and propose ways to address the challenges associated with the juxtaposition of four highly loaded concepts: extreme - event - attribution - climate services.

  5. Bottom-up-then-up-down Route for Multi-level Construction of Hierarchical Bi2S3 Superstructures with Magnetism Alteration.

    Science.gov (United States)

    Wei, Chengzhen; Wang, Lanfang; Dang, Liyun; Chen, Qun; Lu, Qingyi; Gao, Feng

    2015-06-01

    A bottom-up-then-up-down route was proposed to construct multi-level Bi2S3 hierarchical architectures assembled by two-dimensional (2D) Bi2S3 sheet-like networks. BiOCOOH hollow spheres and flower-like structures, which are both assembled by 2D BiOCOOH nanosheets, were prepared first by a "bottom-up" route through a "quasi-emulsion" mechanism. Then the BiOCOOH hierarchical structures were transferred to hierarchical Bi2S3 architectures through an "up-down" route by an ion exchange method. The obtained Bi2S3 nanostructures remain hollow-spherical and flower-like structures of the precursors but the constructing blocks are changed to 2D sheet-like networks interweaving by Bi2S3 nanowires. The close matching of crystal lattices between Bi2S3 and BiOCOOH was believed to be the key reason for the topotactic transformation from BiOCOOH nanosheets to 2D Bi2S3 sheet-like nanowire networks. Magnetism studies reveal that unlike diamagnetism of comparative Bi2S3 nanostructures, the obtained multi-level Bi2S3 structures display S-type hysteresis and ferromagnetism at low field which might result from ordered structure of 2D networks.

  6. Increased water salinity applied to tomato plants accelerates the development of the leaf miner Tuta absoluta through bottom-up effects

    Science.gov (United States)

    Han, Peng; Wang, Zhi-jian; Lavoir, Anne-Violette; Michel, Thomas; Seassau, Aurélie; Zheng, Wen-yan; Niu, Chang-ying; Desneux, Nicolas

    2016-01-01

    Variation in resource inputs to plants may trigger bottom-up effects on herbivorous insects. We examined the effects of water input: optimal water vs. limited water; water salinity: with vs. without addition of 100 mM NaCl; and their interactions on tomato plants (Solanum lycopersicum), and consequently, the bottom-up effects on the tomato leaf miner, Tuta absoluta (Meytick) (Lepidoptera: Gelechiidae). Plant growth was significantly impeded by limited water input and NaCl addition. In terms of leaf chemical defense, the production of tomatidine significantly increased with limited water and NaCl addition, and a similar but non-significant trend was observed for the other glycoalkaloids. Tuta absoluta survival did not vary with the water and salinity treatments, but the treatment “optimal water-high salinity” increased the development rate without lowering pupal mass. Our results suggest that caution should be used in the IPM program against T. absoluta when irrigating tomato crops with saline water. PMID:27619473

  7. Diagnostic, design and implementation of an integrated model of care in France: a bottom-up process with a continuous leadership

    Science.gov (United States)

    de Stampa, Matthieu; Vedel, Isabelle; Mauriat, Claire; Bagaragaza, Emmanuel; Routelous, Christelle; Bergman, Howard; Lapointe, Liette; Cassou, Bernard; Ankri, Joel; Henrard, Jean-Claude

    2010-01-01

    Purpose To present an innovative bottom-up and pragmatic strategy used to implement a new integrated care model in France for community-dwelling elderly people with complex needs. Context Sustaining integrated care is difficult, in large part because of problems encountered securing the participation of health care and social service professionals and, in particular, general practitioners (GPs). Case description In the first step, a diagnostic study was conducted with face-to-face interviews to gather data on current practices from a sample of health and social stakeholders working with elderly people. In the second step, an integrated care model called Coordination Personnes Agées (COPA) was designed by the same major stakeholders in order to define its detailed characteristics based on the local context. In the third step, the model was implemented in two phases: adoption and maintenance. This strategy was carried out by a continuous and flexible leadership throughout the process, initially with a mixed leadership (clinician and researcher) followed by a double one (clinician and managers of services) in the implementation phase. Conclusions The implementation of this bottom-up and pragmatic strategy relied on establishing a collaborative dynamic among health and social stakeholders. This enhanced their involvement throughout the implementation phase, particularly among the GPs, and allowed them to support the change practices and services arrangements.

  8. Semiconductor quantum templates: bottom-up design of optical devices and photonic circuits using sub-nanoscale high monolayer features and quantum optics.

    Science.gov (United States)

    Sadeghi, S M

    2008-02-27

    We propose an alternative bottom-up technique for designing, fabricating and monolithically integrating optical components, including functional distributed feedback lasers, modulators, waveguides, etc in a single semiconductor wafer without any need for etching or post-processing epitaxial growth. The proposed technique is based on the formation of semiconductor quantum templates at the well/barrier interfaces of quantum well structures. Such templates are responsible for changing the thickness of a quantum well in designated regions by adding one extra monolayer of the well material in those regions during the growth process. We show that, using a control laser field, these templates or sub-nanoscale high monolayer features allow us to spatially control the formation of electromagnetically induced transparency, gain without inversion, and coherent enhancement/suppression of the refractive index along the plane of the quantum well. We demonstrate that this can lead to bottom-up design capabilities for functional optical devices and their monolithic integration using a single epitaxial growth process.

  9. Lysine conjugation properties in human IgGs studied by integrating high-resolution native mass spectrometry and bottom-up proteomics.

    Science.gov (United States)

    Gautier, Violette; Boumeester, Anja J; Lössl, Philip; Heck, Albert J R

    2015-08-01

    Antibody-drug conjugates (ADCs) are a novel class of biopharmaceuticals several of which are now being investigated in clinical studies. In ADCs, potent cytotoxic drugs are coupled via a linker to reactive residues in IgG monoclonal antibodies. Linkage to lysine residues in the IgGs, using N-hydroxysuccinimide ester based chemistry, is one of the possible options. To control drug load and specificity, proper knowledge is required about which lysine residues are most accessible and reactive. Here, we combine native MS and bottom-up proteomics to monitor the overall drug load and site-specific lysine reactivity, using N-hydroxysuccinimide-based tandem mass tags. High-resolution Orbitrap native MS enables us to monitor and quantify, due to the achieved baseline resolution, the sequential incorporation of up to 69 tandem mass tag molecules into human IgGs. Complementary, bottom-up proteomics facilitates the identification of some very reactive "hot-spot" conjugation sites. However, we also identify lysine residues that are highly resistant to chemical labeling. Our integrated approach gives insight into the conjugation properties of IgGs at both the intact protein and residue levels, providing fundamental information for controlling drug load and specificity in lysine-linked ADCs. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. A Bottom-Up Building Stock Model for Tracking Regional Energy Targets—A Case Study of Kočevje

    Directory of Open Access Journals (Sweden)

    Marjana Šijanec Zavrl

    2016-10-01

    Full Text Available The paper addresses the development of a bottom-up building stock energy model (BuilS for identification of the building stock renovation potential by considering energy performance of individual buildings through cross-linked data from various public available databases. The model enables integration of various EE and RES measures on the building stock to demonstrate long-term economic and environmental effects of different building stock refurbishment strategies. In the presented case study, the BuilS model was applied in the Kočevje city area and validated using the measured energy consumption of the buildings connected to the city district heating system. Three strategies for improving the building stock in Kočevje towards a more sustainable one are presented with their impact on energy use and CO2 emission projections up to 2030. It is demonstrated that the BuilS bottom-up model enables the setting of a correct baseline regarding energy use of the existing building stock and that such a model is a powerful tool for design and validation of the building stock renovation strategies. It is also shown that the accuracy of the model depends on available information on local resources and local needs, therefore acceleration of the building stock monitoring on the level of each building and continually upgrading of databases with building renovation information is of the utmost importance.

  11. Aberrant salience, self-concept clarity, and interview-rated psychotic-like experiences.

    Science.gov (United States)

    Cicero, David C; Docherty, Anna R; Becker, Theresa M; Martin, Elizabeth A; Kerns, John G

    2015-02-01

    Many social-cognitive models of psychotic-like symptoms posit a role for self-concept and aberrant salience. Previous work has shown that the interaction between aberrant salience and self-concept clarity is associated with self-reported psychotic-like experiences. In the current research with two structured interviews, the interaction between aberrant salience and self-concept clarity was found to be associated with interview-rated psychotic-like experiences. The interaction was associated with psychotic-like experiences composite scores, delusional ideation, grandiosity, and perceptual anomalies. In all cases, self-concept clarity was negatively associated with psychotic-like experiences at high levels of aberrant salience, but unassociated with psychotic-like experiences at low levels of aberrant salience. The interaction was specific to positive psychotic-like experiences and not present for negative or disorganized ratings. The interaction was not mediated by self-esteem levels. These results provide further evidence that aberrant salience and self-concept clarity play an important role in the generation of psychotic-like experiences.

  12. Long-term observations of black carbon mass concentrations at Fukue Island, western Japan, during 2009-2015: Evaluating bottom-up emission inventories for East Asia

    Science.gov (United States)

    Kanaya, Y.; PAN, X.; Miyakawa, T.; Komazaki, Y.; Taketani, F.; Uno, I.; Kondo, Y.

    2016-12-01

    Long-term (2009-2015) observations of atmospheric black carbon (BC) mass concentrations were performed using a continuous soot-monitoring system (COSMOS) at Fukue Island, western Japan, to provide information on wet removal rate constraints and the emission strengths of important source regions in East Asia (China and others). Here we focus on the analysis of spatio-temporal variations in the BC/CO emission ratio. For the analysis, we only used the observed ΔBC/ΔCO ratio when precipitation did not occur along the backward trajectories for 72 hours. Backward trajectory analysis was also used to classify the air mass origin areas. For individual origin areas, cases with BC concentrations in the highest 25% range, with maximum relative humidity along the trajectory over the previous three days in the lowest 25% range, and with the traveling times in the shortest 25% range were critically selected for the analysis. The observed tendencies that the average ΔBC/ΔCO ratio was higher for the air masses from south Central East China (S-CEC, 7.6 ng m-3 ppb-1) than that from North-CEC (6.4 ng m-3 ppb-1) and that the ratio was higher in winter than spring in S-CEC suggested stronger influence from domestic sector in S-CEC. The REAS2 bottom up emission inventory qualitatively captured these features; quantitatively however, the emission ratios were overestimated at least by a factor of 1.3. For Korea, the observed ΔBC/ΔCO ratio (8.4 ng m-3 ppb-1) was significantly overpredicted by REAS2 (23.2 ng m-3 ppb-1), pointing to the necessity of revising the emission database. The large discrepancy seems originating from too high BC/CO emission ratios assumed for industry and transportation sectors in emission inventory studies (e.g., 42 and 27 ng m-3 ppb-1 for REAS2). The results were similar for MEIC and CAPSS, emission inventories developed in China and Korea, respectively. On the other hand, the observed ratio for Japan (6.7 ng m-3 ppb-1) only differed slightly ( 10%) from the

  13. Toward consistency between trends in bottom-up CO2 emissions and top-down atmospheric measurements in the Los Angeles megacity

    Directory of Open Access Journals (Sweden)

    S. Newman

    2016-03-01

    Full Text Available Large urban emissions of greenhouse gases result in large atmospheric enhancements relative to background that are easily measured. Using CO2 mole fractions and Δ14C and δ13C values of CO2 in the Los Angeles megacity observed in inland Pasadena (2006–2013 and coastal Palos Verdes peninsula (autumn 2009–2013, we have determined time series for CO2 contributions from fossil fuel combustion (Cff for both sites and broken those down into contributions from petroleum and/or gasoline and natural gas burning for Pasadena. We find a 10 % reduction in Pasadena Cff during the Great Recession of 2008–2010, which is consistent with the bottom-up inventory determined by the California Air Resources Board. The isotopic variations and total atmospheric CO2 from our observations are used to infer seasonality of natural gas and petroleum combustion. The trend of CO2 contributions to the atmosphere from natural gas combustion is out of phase with the seasonal cycle of total natural gas combustion seasonal patterns in bottom-up inventories but is consistent with the seasonality of natural gas usage by the area's electricity generating power plants. For petroleum, the inferred seasonality of CO2 contributions from burning petroleum is delayed by several months relative to usage indicated by statewide gasoline taxes. Using the high-resolution Hestia-LA data product to compare Cff from parts of the basin sampled by winds at different times of year, we find that variations in observed fossil fuel CO2 reflect seasonal variations in wind direction. The seasonality of the local CO2 excess from fossil fuel combustion along the coast, on Palos Verdes peninsula, is higher in autumn and winter than spring and summer, almost completely out of phase with that from Pasadena, also because of the annual variations of winds in the region. Variations in fossil fuel CO2 signals are consistent with sampling the bottom-up Hestia-LA fossil CO2 emissions product for sub

  14. Toward consistency between bottom-up CO2 emissions trends and top-down atmospheric measurements in the Los Angeles megacity

    Science.gov (United States)

    Newman, S.; Xu, X.; Gurney, K. R.; Hsu, Y.-K.; Li, K.-F.; Jiang, X.; Keeling, R.; Feng, S.; O'Keefe, D.; Patarasuk, R.; Wong, K. W.; Rao, P.; Fischer, M. L.; Yung, Y. L.

    2015-10-01

    Large urban emissions of greenhouse gases result in large atmospheric enhancements relative to background that are easily measured. Using CO2 mole fractions and Δ14C and δ13C values of CO2 in the Los Angeles megacity observed in inland Pasadena (2006-2013) and coastal Palos Verdes peninsula (autumn 2009-2013), we have determined time series for CO2 contributions from fossil fuel combustion for both sites and broken those down into contributions from petroleum/gasoline and natural gas burning for Pasadena. We find a 10 % reduction in Pasadena CO2 emissions from fossil fuel combustion during the Great Recession of 2008-2010, which is consistent with the bottom-up inventory determined by the California Air Resources Board. The isotopic variations and total atmospheric CO2 from our observations are used to infer seasonality of natural gas and petroleum combustion. For natural gas, inferred emissions are out of phase with the seasonal cycle of total natural gas combustion seasonal patterns in bottom-up inventories but are consistent with the seasonality of natural gas usage by the area's electricity generating power plants. For petroleum, the inferred seasonality of CO2 emissions from burning petroleum is delayed by several months relative to usage indicated by statewide gasoline taxes. Using the high-resolution Hestia-LA data product to compare emissions from parts of the basin sampled by winds at different times of year, we find that variations in observed fossil fuel CO2 reflect seasonal variations in wind direction. The seasonality of the local CO2 excess from fossil fuel combustion along the coast, on Palos Verdes peninsula, is higher in fall and winter than spring and summer, almost completely out of phase with that from Pasadena, also because of the annual variations of winds in the region. Variations in fossil fuel CO2 signals are consistent with sampling the bottom-up Hestia-LA fossil CO2 emissions product for sub-city source regions in the LA megacity domain

  15. Toward consistency between trends in bottom-up CO2 emissions and top-down atmospheric measurements in the Los Angeles megacity

    Science.gov (United States)

    Newman, Sally; Xu, Xiaomei; Gurney, Kevin R.; Kuang Hsu, Ying; Li, King Fai; Jiang, Xun; Keeling, Ralph; Feng, Sha; O'Keefe, Darragh; Patarasuk, Risa; Weng Wong, Kam; Rao, Preeti; Fischer, Marc L.; Yung, Yuk L.

    2016-03-01

    Large urban emissions of greenhouse gases result in large atmospheric enhancements relative to background that are easily measured. Using CO2 mole fractions and Δ14C and δ13C values of CO2 in the Los Angeles megacity observed in inland Pasadena (2006-2013) and coastal Palos Verdes peninsula (autumn 2009-2013), we have determined time series for CO2 contributions from fossil fuel combustion (Cff) for both sites and broken those down into contributions from petroleum and/or gasoline and natural gas burning for Pasadena. We find a 10 % reduction in Pasadena Cff during the Great Recession of 2008-2010, which is consistent with the bottom-up inventory determined by the California Air Resources Board. The isotopic variations and total atmospheric CO2 from our observations are used to infer seasonality of natural gas and petroleum combustion. The trend of CO2 contributions to the atmosphere from natural gas combustion is out of phase with the seasonal cycle of total natural gas combustion seasonal patterns in bottom-up inventories but is consistent with the seasonality of natural gas usage by the area's electricity generating power plants. For petroleum, the inferred seasonality of CO2 contributions from burning petroleum is delayed by several months relative to usage indicated by statewide gasoline taxes. Using the high-resolution Hestia-LA data product to compare Cff from parts of the basin sampled by winds at different times of year, we find that variations in observed fossil fuel CO2 reflect seasonal variations in wind direction. The seasonality of the local CO2 excess from fossil fuel combustion along the coast, on Palos Verdes peninsula, is higher in autumn and winter than spring and summer, almost completely out of phase with that from Pasadena, also because of the annual variations of winds in the region. Variations in fossil fuel CO2 signals are consistent with sampling the bottom-up Hestia-LA fossil CO2 emissions product for sub-city source regions in the LA

  16. Visual saliency detection using local patches contrast

    Science.gov (United States)

    Xie, Zhao-xia; Du, Yan-ping; Lu, Hai-ming; Yang, Zi-jing

    2017-07-01

    Human vision system possesses a strong ability to interpret complex scenes in real time effortlessly and efficiently. However, computational modeling of basic intelligent behavior still remains a significant challenge in the fields of computer vision system. Different from context-aware saliency algorithm, our method for saliency detection, not only using basic properties of visual attention but also introducing local patches contrast cues, thus it can effectively improve the accuracy of visual saliency detection with relatively low computational complexity. Furthermore, the experimental results also indicate that the effectiveness of our proposed method.

  17. Salience Assignment for Multiple-Instance Regression

    Science.gov (United States)

    Wagstaff, Kiri L.; Lane, Terran

    2007-01-01

    We present a Multiple-Instance Learning (MIL) algorithm for determining the salience of each item in each bag with respect to the bag's real-valued label. We use an alternating-projections constrained optimization approach to simultaneously learn a regression model and estimate all salience values. We evaluate this algorithm on a significant real-world problem, crop yield modeling, and demonstrate that it provides more extensive, intuitive, and stable salience models than Primary-Instance Regression, which selects a single relevant item from each bag.

  18. Rethinking translational nanomedicine: insights from the 'bottom-up' design of the Porphysome for guiding the clinical development of imageable nanomaterials.

    Science.gov (United States)

    Valic, Michael S; Zheng, Gang

    2016-08-01

    Progress in therapeutics and biotechnologies leveraging new insights in our understanding of cancer biology and progression have had an underwhelming clinical significance thus far. A key challenge arising from the creation of nanomedicines consolidating multiple desirable functionalities into a 'all-in-one' platform is that the layering of functionalities into a single agent introduces novel complexities that significantly impede clinical translation. An alternative design approach seeks to exploit intrinsically multi-functional building block to assemble nanomedicines from the bottom-up, yielding agents with a multiplicity of radiologic, pharmacologic, and therapeutic properties derived from a single constituent. Herein are highlighted recent developments in the formulation, multi-modal imaging, and targeting of an exemplary 'one-for-all' nanomaterial-the Pyropheophorbide Porphysome-treated from a hitherto unexplored clinical design and development perspective. Copyright © 2016 Elsevier Ltd. All rights reserved.

  19. Bottom-up processing of thermoelectric nanocomposites from colloidal nanocrystal building blocks: the case of Ag{sub 2}Te-PbTe

    Energy Technology Data Exchange (ETDEWEB)

    Cadavid, Doris [Catalonia Institute for Energy Research, IREC (Spain); Ibanez, Maria [Universitat de Barcelona, Departament d' Electronica (Spain); Gorsse, Stephane [Universite de Bordeaux, ICMCB, CNRS (France); Lopez, Antonio M. [Universitat Politecnica de Catalunya, Departament d' Enginyeria Electronica (Spain); Cirera, Albert [Universitat de Barcelona, Departament d' Electronica (Spain); Morante, Joan Ramon; Cabot, Andreu, E-mail: acabot@irec.cat [Catalonia Institute for Energy Research, IREC (Spain)

    2012-12-15

    Nanocomposites are highly promising materials to enhance the efficiency of current thermoelectric devices. A straightforward and at the same time highly versatile and controllable approach to produce nanocomposites is the assembly of solution-processed nanocrystal building blocks. The convenience of this bottom-up approach to produce nanocomposites with homogeneous phase distributions and adjustable composition is demonstrated here by blending Ag{sub 2}Te and PbTe colloidal nanocrystals to form Ag{sub 2}Te-PbTe bulk nanocomposites. The thermoelectric properties of these nanocomposites are analyzed in the temperature range from 300 to 700 K. The evolution of their electrical conductivity and Seebeck coefficient is discussed in terms of the blend composition and the characteristics of the constituent materials.

  20. Fishermen or Swarm Dynamics? Should we Understand Jihadist Online-Radicalization as a Top-Down or Bottom-Up Process?

    Directory of Open Access Journals (Sweden)

    Till Baaken

    2017-12-01

    Full Text Available The internet has profoundly changed the way we communicate, including how jihadist groups seek to reach Western audiences with their propaganda strategies. Cases of believed online-radicalization call for a re-evaluation of radicalization processes, previously thought to depend on face-to-face interactions. Based on the Hoffman-Sageman debate on whether top-down or bottom-up processes drive terrorism, this essay explores both social movement and organizational approaches to understand online-radicalization. Do jihadist organizations such as Al-Qaeda and IS act as ‘fishermen’, actively engaging in the radicalization processes of individual recruits, or is radicalization driven by social group dynamics with little organizational involvement? Essentially, the larger question is: What role do organizational structures play for radicalization in times of ‘virtual jihad’? Bottom-up radicalization processes are facilitated online, because the conditions for Sageman’s ‘bunch of guys’ are replicated by the characteristics of virtual communication: an echo chamber effect causes frame-alignment through repetition and enables ‘digital natives’ to communicate claims that resonate with other ‘digital natives’. Top-down structures are influential, because organizations continue to employ sophisticated propaganda development, preachers and special recruiters or ‘fishermen’. The article finds evidence for both schools of thought and concludes that the internet facilitates both types of radicalization mechanisms. Only a holistic strategy will be successful in battling online-radicalization and must include both targeting direct channels through which the organizations execute control over recruits, and breaking the echo chamber created by social movement dynamics in the virtual world. While countermeasures need to include the provision of alternative social narratives and the utilization of ‘digital natives’ to make counter

  1. Top-down and bottom-up interactions influence fledging success at North America’s largest colony of Caspian terns (Hydroprogne caspia)

    Science.gov (United States)

    Collar, Stefanie; Roby, Daniel D.; Lyons, Donald E.

    2017-01-01

    Our study investigated the influence of bottom-up and top-down drivers on the declining fledging success at a once thriving breeding colony of Caspian terns (Hydroprogne caspia). Situated at the mouth of the Columbia River, OR, East Sand Island (ESI) is home to the largest Caspian tern breeding colony in North America. Since 2001, the decline in fledging success of Caspian terns at ESI has been associated with a significant increase in average river discharge during May and June. During the years 2001–2011, the abundance of forage fish available to terns in the estuary was inversely related to river discharge. This relationship also apparently affected the reliance of nest predators on the tern colony as a food source, resulting in increased disturbance and decreased fledging success at the tern colony in years of higher river discharge. There was a significant longitudinal increase in disturbance rates by bald eagles (Haliaeetus leucocephalus) during June for terns nesting at the ESI colony, and eagle disturbance rates were positively associated with May river discharge. We also found a significant increase in kleptoparasitism rates of terns by hybrid glaucous-winged/western gulls (Larus glaucescens x Larus occidentalis) since 2001, and Caspian tern fledging success at ESI decreased with increasing average annual rates of gull kleptoparasitism. Our results support the hypothesis that the decline in Caspian tern fledging success at this large estuarine colony was primarily driven by the interaction of bottom-up and top-down factors, influencing tern fledging success through the food supply and triggering potential predators to identify the tern breeding colony as an alternative source of prey.

  2. Dynamic causal modeling in PTSD and its dissociative subtype: Bottom-up versus top-down processing within fear and emotion regulation circuitry.

    Science.gov (United States)

    Nicholson, Andrew A; Friston, Karl J; Zeidman, Peter; Harricharan, Sherain; McKinnon, Margaret C; Densmore, Maria; Neufeld, Richard W J; Théberge, Jean; Corrigan, Frank; Jetly, Rakesh; Spiegel, David; Lanius, Ruth A

    2017-11-01

    Posttraumatic stress disorder (PTSD) is associated with decreased top-down emotion modulation from medial prefrontal cortex (mPFC) regions, a pathophysiology accompanied by hyperarousal and hyperactivation of the amygdala. By contrast, PTSD patients with the dissociative subtype (PTSD + DS) often exhibit increased mPFC top-down modulation and decreased amygdala activation associated with emotional detachment and hypoarousal. Crucially, PTSD and PTSD + DS display distinct functional connectivity within the PFC, amygdala complexes, and the periaqueductal gray (PAG), a region related to defensive responses/emotional coping. However, differences in directed connectivity between these regions have not been established in PTSD, PTSD + DS, or controls. To examine directed (effective) connectivity among these nodes, as well as group differences, we conducted resting-state stochastic dynamic causal modeling (sDCM) pairwise analyses of coupling between the ventromedial (vm)PFC, the bilateral basolateral and centromedial (CMA) amygdala complexes, and the PAG, in 155 participants (PTSD [n = 62]; PTSD + DS [n = 41]; age-matched healthy trauma-unexposed controls [n = 52]). PTSD was characterized by a pattern of predominant bottom-up connectivity from the amygdala to the vmPFC and from the PAG to the vmPFC and amygdala. Conversely, PTSD + DS exhibited predominant top-down connectivity between all node pairs (from the vmPFC to the amygdala and PAG, and from the amygdala to the PAG). Interestingly, the PTSD + DS group displayed the strongest intrinsic inhibitory connections within the vmPFC. These results suggest the contrasting symptom profiles of PTSD and its dissociative subtype (hyper- vs. hypo-emotionality, respectively) may be driven by complementary changes in directed connectivity corresponding to bottom-up defensive fear processing versus enhanced top-down regulation. Hum Brain Mapp 38:5551-5561, 2017. © 2017 Wiley Periodicals, Inc.

  3. Theta-gamma coupling reflects the interaction of bottom-up and top-down processes in speech perception in children.

    Science.gov (United States)

    Wang, Juan; Gao, Danqi; Li, Duan; Desroches, Amy S; Liu, Li; Li, Xiaoli

    2014-11-15

    This study investigates how the interaction of different brain oscillations (particularly theta-gamma coupling) modulates the bottom-up and top-down processes during speech perception. We employed a speech perception paradigm that manipulated the congruency between a visually presented picture and an auditory stimulus and asked participants to judge whether they matched or mismatched. A group of children (mean age 10 years, 5 months) participated in this study and their electroencephalographic (EEG) data were recorded while performing the experimental task. It was found that in comparison with mismatch condition, match condition facilitated speech perception by eliciting greater theta-gamma coupling in the frontal area and smaller theta-gamma coupling in the left temporal area. These findings suggested that a top-down facilitation effect from congruent visual pictures engaged different mechanisms in low-level sensory (temporal) regions and high-level linguistic and decision (frontal) regions. Interestingly, hemispheric asymmetry is with higher theta-gamma coupling in the match condition in the right hemisphere and higher theta-gamma coupling in the mismatch condition in the left hemisphere. This indicates that a fast global processing strategy and a slow detailed processing strategy were differentially adopted in the match and mismatch conditions. This study provides new insight into the mechanisms of speech perception from the interaction of different oscillatory activities and provides neural evidence for theories of speech perception allowing for top-down feedback connections. Furthermore, it sheds light on children's speech perception development by showing a similar pattern of integration of bottom-up and top-down information during speech perception as previous studies have revealed in adults. Copyright © 2014 Elsevier Inc. All rights reserved.

  4. "Disorganized in time": impact of bottom-up and top-down negative emotion generation on memory formation among healthy and traumatized adolescents.

    Science.gov (United States)

    Guillery-Girard, Bérengère; Clochon, Patrice; Giffard, Bénédicte; Viard, Armelle; Egler, Pierre-Jean; Baleyte, Jean-Marc; Eustache, Francis; Dayan, Jacques

    2013-09-01

    "Travelling in time," a central feature of episodic memory is severely affected among individuals with Post Traumatic Stress Disorder (PTSD) with two opposite effects: vivid traumatic memories are unorganized in temporality (bottom-up processes), non-traumatic personal memories tend to lack spatio-temporal details and false recognitions occur more frequently that in the general population (top-down processes). To test the effect of these two types of processes (i.e. bottom-up and top-down) on emotional memory, we conducted two studies in healthy and traumatized adolescents, a period of life in which vulnerability to emotion is particularly high. Using negative and neutral images selected from the international affective picture system (IAPS), stimuli were divided into perceptual images (emotion generated by perceptual details) and conceptual images (emotion generated by the general meaning of the material). Both categories of stimuli were then used, along with neutral pictures, in a memory task with two phases (encoding and recognition). In both populations, we reported a differential effect of the emotional material on encoding and recognition. Negative perceptual scenes induced an attentional capture effect during encoding and enhanced the recollective distinctiveness. Conversely, the encoding of conceptual scenes was similar to neutral ones, but the conceptual relatedness induced false memories at retrieval. However, among individuals with PTSD, two subgroups of patients were identified. The first subgroup processed the scenes faster than controls, except for the perceptual scenes, and obtained similar performances to controls in the recognition task. The second subgroup group desmonstrated an attentional deficit in the encoding task with no benefit from the distinctiveness associated with negative perceptual scenes on memory performances. These findings provide a new perspective on how negative emotional information may have opposite influences on memory in

  5. Visual scanning and recognition of Chinese, Caucasian, and racially ambiguous faces: contributions from bottom-up facial physiognomic information and top-down knowledge of racial categories.

    Science.gov (United States)

    Wang, Qiandong; Xiao, Naiqi G; Quinn, Paul C; Hu, Chao S; Qian, Miao; Fu, Genyue; Lee, Kang

    2015-02-01

    Recent studies have shown that participants use different eye movement strategies when scanning own- and other-race faces. However, it is unclear (1) whether this effect is related to face recognition performance, and (2) to what extent this effect is influenced by top-down or bottom-up facial information. In the present study, Chinese participants performed a face recognition task with Chinese, Caucasian, and racially ambiguous faces. For the racially ambiguous faces, we led participants to believe that they were viewing either own-race Chinese faces or other-race Caucasian faces. Results showed that (1) Chinese participants scanned the nose of the true Chinese faces more than that of the true Caucasian faces, whereas they scanned the eyes of the Caucasian faces more than those of the Chinese faces; (2) they scanned the eyes, nose, and mouth equally for the ambiguous faces in the Chinese condition compared with those in the Caucasian condition; (3) when recognizing the true Chinese target faces, but not the true target Caucasian faces, the greater the fixation proportion on the nose, the faster the participants correctly recognized these faces. The same was true when racially ambiguous face stimuli were thought to be Chinese faces. These results provide the first evidence to show that (1) visual scanning patterns of faces are related to own-race face recognition response time, and (2) it is bottom-up facial physiognomic information that mainly contributes to face scanning. However, top-down knowledge of racial categories can influence the relationship between face scanning patterns and recognition response time. Copyright © 2014 Elsevier Ltd. All rights reserved.

  6. Capillary zone electrophoresis-mass spectrometry with microliter-scale loading capacity, 140 min separation window and high peak capacity for bottom-up proteomics.

    Science.gov (United States)

    Chen, Daoyang; Shen, Xiaojing; Sun, Liangliang

    2017-06-21

    Better peptide separation is required for bottom-up proteomics for further improving the proteome coverage. The two-dimensional liquid chromatography (2D-LC) systems only explore differences among peptides in their hydrophobicity (reversed-phase, RP) and charge (strong cation/anion exchange, SCX/SAX). Alternative separation techniques with different separation mechanisms are required to further improve the separation. Capillary zone electrophoresis (CZE) is an attractive alternative because it has high efficiency for separation of biomolecules and it separates analytes based on their size-to-charge ratios, complementary with LC. However, the low loading capacity and narrow separation window of CZE limit its wide application for large-scale proteomics. In this manuscript, we present an automated CZE-mass spectrometry (MS) system for solving those issues. The CZE-MS system can approach at least half-a-microliter loading capacity with good robustness and reproducibility, can routinely use over 12% of the available sample in the sample vial for analysis, and can generate a 140 min separation window and high peak capacity (∼380) for complex proteome analysis. The results represent the highest peak capacity and the widest separation window of CZE for peptide separation with a microliter-scale loading capacity. It is the first time that CZE-MS approaches both the microliter-scale loading capacity and over 2-hour separation window for analysis of complex samples. The automated CZE-MS system dramatically reduces the gap between CZE-MS and RPLC-MS in terms of loading capacity, separation window and peak capacity. It truly opens the door for large-scale bottom-up proteomics using CZE-MS.

  7. Identifying the computational requirements of an integrated top-down-bottom-up model for overt visual attention within an active vision system.

    Directory of Open Access Journals (Sweden)

    Sebastian McBride

    Full Text Available Computational visual attention systems have been constructed in order for robots and other devices to detect and locate regions of interest in their visual world. Such systems often attempt to take account of what is known of the human visual system and employ concepts, such as 'active vision', to gain various perceived advantages. However, despite the potential for gaining insights from such experiments, the computational requirements for visual attention processing are often not clearly presented from a biological perspective. This was the primary objective of this study, attained through two specific phases of investigation: 1 conceptual modeling of a top-down-bottom-up framework through critical analysis of the psychophysical and neurophysiological literature, 2 implementation and validation of the model into robotic hardware (as a representative of an active vision system. Seven computational requirements were identified: 1 transformation of retinotopic to egocentric mappings, 2 spatial memory for the purposes of medium-term inhibition of return, 3 synchronization of 'where' and 'what' information from the two visual streams, 4 convergence of top-down and bottom-up information to a centralized point of information processing, 5 a threshold function to elicit saccade action, 6 a function to represent task relevance as a ratio of excitation and inhibition, and 7 derivation of excitation and inhibition values from object-associated feature classes. The model provides further insight into the nature of data representation and transfer between brain regions associated with the vertebrate 'active' visual attention system. In particular, the model lends strong support to the functional role of the lateral intraparietal region of the brain as a primary area of information consolidation that directs putative action through the use of a 'priority map'.

  8. Effects of Communication Mode and Salience on Recasts: A First Exposure Study

    Science.gov (United States)

    Yilmaz, Yucel; Yuksel, Dogan

    2011-01-01

    This article reports on a study that investigated whether the extent to which learners benefit from recasts on two Turkish morphemes differ depending on communication mode--i.e. Face-to-Face Communication (F2FC) and text-based Synchronous Computer-Mediated Communication (SCMC)--and/or the salience of the target structure (i.e. salient and…

  9. Isolating the Incentive Salience of Reward-Associated Stimuli: Value, Choice, and Persistence

    Science.gov (United States)

    Beckmann, Joshua S.; Chow, Jonathan J.

    2015-01-01

    Sign- and goal-tracking are differentially associated with drug abuse-related behavior. Recently, it has been hypothesized that sign- and goal-tracking behavior are mediated by different neurobehavioral valuation systems, including differential incentive salience attribution. Herein, we used different conditioned stimuli to preferentially elicit…

  10. Do positive spontaneous thoughts function as incentive salience?

    Science.gov (United States)

    Rice, Elise L; Fredrickson, Barbara L

    2017-08-01

    The present work explores the theoretical relationship between positive spontaneous thoughts and incentive salience-a psychological property thought to energize wanting and approach motivation by rendering cues that are associated with enjoyment more likely to stand out to the individual when subsequently encountered in the environment (Berridge, 2007). We reasoned that positive spontaneous thoughts may at least be concomitants of incentive salience, and as such, they might likewise mediate the effect of liking on wanting. In Study 1, 103 adults recruited via Amazon's Mechanical Turk reported on key aspects of 10 everyday activities. As predicted, positive spontaneous thoughts mediated the relationship between liking an activity in the past and wanting to engage in it in the future. In Study 2, 99 undergraduate students viewed amusing and humorless cartoons and completed a thought-listing task, providing experimental evidence for the causal effect of liking on positive spontaneous thoughts. In Study 3, we tested whether positive spontaneous thoughts play an active role in energizing wanting rather than merely co-occurring with (inferred) incentive salience. In that experiment involving 80 undergraduates, participants who were led to believe that their spontaneous thoughts about a target activity were especially positive planned to devote more time to that activity over the coming week than participants who received no such information about their spontaneous thoughts. Collectively, these findings suggest that positive spontaneous thoughts may play an important role in shaping approach motivation. Broader implications and future directions in the study of positive spontaneous thoughts are discussed. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

  11. Top-down and bottom-up: Front to back. Comment on "Move me, astonish me... delight my eyes and brain: The Vienna Integrated Model of top-down and bottom-up processes in Art Perception (VIMAP) and corresponding affective, evaluative, and neurophysiological correlates" by Matthew Pelowski et al.

    Science.gov (United States)

    Nadal, Marcos; Skov, Martin

    2017-07-01

    The model presented here [1] is the latest in an evolving series of psychological models aimed at explaining the experience of art, first proposed by Leder and colleagues [2]. The aim of this new version is to ;explicitly connect early bottom-up, artwork-derived processing sequence and outputs to top-down, viewer-derived contribution to the processing sequence; [1, p. 5f & 6]. The ;meeting; of these two processing sequences, the authors contend, is crucial to the understanding of people's responses to art [sections 3.6ff & 4], and therefore the new model's principal motivation.

  12. A Local Texture-Based Superpixel Feature Coding for Saliency Detection Combined with Global Saliency

    Directory of Open Access Journals (Sweden)

    Bingfei Nan

    2015-12-01

    Full Text Available Because saliency can be used as the prior knowledge of image content, saliency detection has been an active research area in image segmentation, object detection, image semantic understanding and other relevant image-based applications. In the case of saliency detection from cluster scenes, the salient object/region detected needs to not only be distinguished clearly from the background, but, preferably, to also be informative in terms of complete contour and local texture details to facilitate the successive processing. In this paper, a Local Texture-based Region Sparse Histogram (LTRSH model is proposed for saliency detection from cluster scenes. This model uses a combination of local texture patterns and color distribution as well as contour information to encode the superpixels to characterize the local feature of image for region contrast computing. Combining the region contrast as computed with the global saliency probability, a full-resolution salient map, in which the salient object/region detected adheres more closely to its inherent feature, is obtained on the bases of the corresponding high-level saliency spatial distribution as well as on the pixel-level saliency enhancement. Quantitative comparisons with five state-of-the-art saliency detection methods on benchmark datasets are carried out, and the comparative results show that the method we propose improves the detection performance in terms of corresponding measurements.

  13. Comparing bottom-up and top-down approaches at the landscape scale, including agricultural activities and water systems, at the Roskilde Fjord, Denmark

    Science.gov (United States)

    Lequy, Emeline; Ibrom, Andreas; Ambus, Per; Massad, Raia-Silvia; Markager, Stiig; Asmala, Eero; Garnier, Josette; Gabrielle, Benoit; Loubet, Benjamin

    2015-04-01

    The greenhouse gas nitrous oxide (N2O) mainly originates in direct emissions from agricultural soils due to microbial reactions stimulated by the use of nitrogen fertilisers. Indirect N2O emissions from water systems due to nitrogen leaching and deposition from crop fields range between 26 and 37% of direct agricultural emissions, indicating their potential importance and uncertainty (Reay et al. 2012). The study presented here couples a top-down approach with eddy covariance (EC) and a bottom-up approach using different models and measurements. A QCL sensor at 96-m height on a tall tower measures the emissions of N2O from 1100 ha of crop fields and from the south part of the Roskilde fjord, in a 5-km radius area around the tall tower at Roskilde, Denmark. The bottom-up approach includes ecosystem modelling with CERES-EGC for the crops and PaSIM for the grasslands, and the N2O fluxes from the Roskilde fjord are derived from N2O sea water concentration measurements. EC measurements are now available from July to December 2014, and indicate a magnitude of the emissions from the crop fields around 0.2 mg N2O-N m-2 day-1 (range -9 to 5) which is consistent with the CERES-EGC simulations and calculations using IPCC emission factors. N2O fluxes from the Roskilde fjord in May and July indicated quite constant N2O concentrations around 0.1 µg N L-1 despite variations of nitrate and ammonium in the fjord. The calculated fluxes from these concentrations and the tall tower measurements consistently ranged between -7 and 6 mg N2O-N m-2 day-1. The study site also contains a waste water treatment plant, whose direct emissions will be measured in early 2015 using a dynamic plume tracer dispersion method (Mønster et al. 2014). A refined source attribution methodology together with more measurements and simulations of the N2O fluxes from the different land uses in this study site will provide a clearer view of the dynamics and budgets of N2O at the regional scale. The

  14. Top-down model estimates, bottom-up inventories, and future projections of global natural and anthropogenic emissions of nitrous oxide

    Science.gov (United States)

    Davidson, E. A.; Kanter, D.

    2013-12-01

    Nitrous oxide (N2O) is the third most abundantly emitted greenhouse gas and the largest remaining emitted ozone depleting substance. It is a product of nitrifying and denitrifying bacteria in soils, sediments and water bodies. Humans began to disrupt the N cycle in the preindustrial era as they expanded agricultural land, used fire for land clearing and management, and cultivated leguminous crops that carry out biological N fixation. This disruption accelerated after the industrial revolution, especially as the use of synthetic N fertilizers became common after 1950. Here we present findings from a new United Nations Environment Programme report, in which we constrain estimates of the anthropogenic and natural emissions of N2O and consider scenarios for future emissions. Inventory-based estimates of natural emissions from terrestrial, marine and atmospheric sources range from 10 to 12 Tg N2O-N/yr. Similar values can be derived for global N2O emissions that were predominantly natural before the industrial revolution. While there was inter-decadal variability, there was little or no consistent trend in atmospheric N2O concentrations between 1730 and 1850, allowing us to assume near steady state. Assuming an atmospheric lifetime of 120 years, the 'top-down' estimate of pre-industrial emissions of 11 Tg N2O-N/yr is consistent with the bottom-up inventories for natural emissions, although the former includes some modest pre-industrial anthropogenic effects (probably period 2000-2007. Based on a review of bottom-up inventories, we estimate total net anthropogenic N2O emissions of 6.0 Tg N2O-N/yr (5.4-8.4 Tg N2O-N/yr). Estimates (and ranges) by sector (in Tg N2O-N/yr) are: agriculture 4.1 Tg (3.8-6.8); biomass burning 0.7 (0.5-1.7); energy and transport 0.7 (0.5-1.2); industry 0.7 (0.3-1.1); and other 0.5 (0.2 - 0.8). Tropical deforestation has reduced emissions by 0.7 (0.5 - 1.0). Given the large inherent uncertainties in both approaches, it is encouraging that the

  15. A Neural Computational Model of Incentive Salience

    Science.gov (United States)

    Zhang, Jun; Berridge, Kent C.; Tindell, Amy J.; Smith, Kyle S.; Aldridge, J. Wayne

    2009-01-01

    Incentive salience is a motivational property with ‘magnet-like’ qualities. When attributed to reward-predicting stimuli (cues), incentive salience triggers a pulse of ‘wanting’ and an individual is pulled toward the cues and reward. A key computational question is how incentive salience is generated during a cue re-encounter, which combines both learning and the state of limbic brain mechanisms. Learning processes, such as temporal-difference models, provide one way for stimuli to acquire cached predictive values of rewards. However, empirical data show that subsequent incentive values are also modulated on the fly by dynamic fluctuation in physiological states, altering cached values in ways requiring additional motivation mechanisms. Dynamic modulation of incentive salience for a Pavlovian conditioned stimulus (CS or cue) occurs during certain states, without necessarily requiring (re)learning about the cue. In some cases, dynamic modulation of cue value occurs during states that are quite novel, never having been experienced before, and even prior to experience of the associated unconditioned reward in the new state. Such cases can include novel drug-induced mesolimbic activation and addictive incentive-sensitization, as well as natural appetite states such as salt appetite. Dynamic enhancement specifically raises the incentive salience of an appropriate CS, without necessarily changing that of other CSs. Here we suggest a new computational model that modulates incentive salience by integrating changing physiological states with prior learning. We support the model with behavioral and neurobiological data from empirical tests that demonstrate dynamic elevations in cue-triggered motivation (involving natural salt appetite, and drug-induced intoxication and sensitization). Our data call for a dynamic model of incentive salience, such as presented here. Computational models can adequately capture fluctuations in cue-triggered ‘wanting’ only by

  16. Linking top-down and bottom-up approaches for assessing the vulnerability of a 100 % renewable energy system in Northern-Italy

    Science.gov (United States)

    Borga, Marco; Francois, Baptiste; Hingray, Benoit; Zoccatelli, Davide; Creutin, Jean-Dominique; brown, Casey

    2016-04-01

    Due to their variable and un-controllable features, integration of Variable Renewable Energies (e.g. solar-power, wind-power and hydropower, denoted as VRE) into the electricity network implies higher production variability and increased risk of not meeting demand. Two approaches are commonly used for assessing this risk and especially its evolution in a global change context (i.e. climate and societal changes); top-down and bottom-up approaches. The general idea of a top-down approach is to drive analysis of global change or of some key aspects of global change on their systems (e.g., the effects of the COP 21, of the deployment of Smart Grids, or of climate change) with chains of loosely linked simulation models within a predictive framework. The bottom-up approach aims to improve understanding of the dependencies between the vulnerability of regional systems and large-scale phenomenon from knowledge gained through detailed exploration of the response to change of the system of interest, which may reveal vulnerability thresholds, tipping points as well as potential opportunities. Brown et al. (2012) defined an analytical framework to merge these two approaches. The objective is to build, a set of Climate Response Functions (CRFs) putting in perspective i) indicators of desired states ("success") and undesired states ("failure") of a system as defined in collaboration with stakeholders 2) exhaustive exploration of the effects of uncertain forcings and imperfect system understanding on the response of the system itself to a plausible set of possible changes, implemented a with multi-dimensionally consistent "stress test" algorithm, and 3) a set "ex post" hydroclimatic and socioeconomic scenarios that provide insight into the differential effectiveness of alternative policies and serve as entry points for the provision of climate information to inform policy evaluation and choice. We adapted this approach for analyzing a 100 % renewable energy system within a region

  17. Dissociated roles of the inferior frontal gyrus and superior temporal sulcus in audiovisual processing: top-down and bottom-up mismatch detection.

    Directory of Open Access Journals (Sweden)

    Takeshi Uno

    Full Text Available Visual inputs can distort auditory perception, and accurate auditory processing requires the ability to detect and ignore visual input that is simultaneous and incongruent with auditory information. However, the neural basis of this auditory selection from audiovisual information is unknown, whereas integration process of audiovisual inputs is intensively researched. Here, we tested the hypothesis that the inferior frontal gyrus (IFG and superior temporal sulcus (STS are involved in top-down and bottom-up processing, respectively, of target auditory information from audiovisual inputs. We recorded high gamma activity (HGA, which is associated with neuronal firing in local brain regions, using electrocorticography while patients with epilepsy judged the syllable spoken by a voice while looking at a voice-congruent or -incongruent lip movement from the speaker. The STS exhibited stronger HGA if the patient was presented with information of large audiovisual incongruence than of small incongruence, especially if the auditory information was correctly identified. On the other hand, the IFG exhibited stronger HGA in trials with small audiovisual incongruence when patients correctly perceived the auditory information than when patients incorrectly perceived the auditory information due to the mismatched visual information. These results indicate that the IFG and STS have dissociated roles in selective auditory processing, and suggest that the neural basis of selective auditory processing changes dynamically in accordance with the degree of incongruity between auditory and visual information.

  18. Quantitative Analysis on the Energy and Environmental Impact of the Korean National Energy R&D Roadmap a Using Bottom-Up Energy System Model

    Directory of Open Access Journals (Sweden)

    Sang Jin Choi

    2017-03-01

    Full Text Available According to the Paris Agreement at the 21st Conference of the Parties, 196 member states are obliged to submit their Intended Nationally Determined Contributions (INDC for every 5 years. As a member, South Korea has already proposed the reduction target and need to submit the achievement as a result of the policies and endeavors in the near future. In this paper, a Korean bottom-up energy system model to support the low-carbon national energy R&D roadmap will be introduced and through the modeling of various scenarios, the mid-to long-term impact on energy consumptions and CO2 emissions will be analyzed as well. The results of the analysis showed that, assuming R&D investments for the 11 types of technologies, savings of 13.7% with regards to final energy consumptions compared to the baseline scenario would be feasible by 2050. Furthermore, in the field of power generation, the generation proportion of new and renewable energy is expected to increase from 3.0% as of 2011 to 19.4% by 2050. This research also suggested that the analysis on the Energy Technology R&D Roadmap based on the model can be used not only for overall impact analysis and R&D portfolio establishment, but also for the development of detailed R&D strategies.

  19. A novel high-speed production process to create modular components for the bottom-up assembly of large scale tissue engineered constructs

    Science.gov (United States)

    Khan, Omar F.; Voice, Derek N.; Leung, Brendan M.

    2014-01-01

    To replace damaged or diseased tissues, large tissue-engineered constructs can be prepared by assembling modular components in a bottom-up approach. However, a high speed method is needed to produce sufficient numbers of these modules for full-sized tissue substitutes. To this end, we have devised a novel production technique that combines air shearing and a plug flow reactor-style design to rapidly produce large quantities of hydrogel-based (here type I collagen) cylindrical modular components with tunable diameters and length. Using this technique, modules containing NIH 3T3 cells showed greater than 95% viability while endothelial cell surface attachment and confluent monolayer formation was demonstrated. Additionally, the rapidly-produced modules were used to assemble large tissue constructs (> 1 cm3) in vitro. Module building blocks containing luciferase-expressing L929 cells were packed in full size adult rat liver-shaped bioreactors and perfused with cell medium, to demonstrate the capacity to build organ-shaped constructs; bioluminescence demonstrated sustained viability over 3 days. Cardiomyocyte embedded modules were also used to assemble electrically stimulatable contractile tissue. PMID:24895070

  20. Direct cost of pars plana vitrectomy for the treatment of macular hole, epiretinal membrane and vitreomacular traction: a bottom-up approach.

    Science.gov (United States)

    Nicod, Elena; Jackson, Timothy L; Grimaccia, Federico; Angelis, Aris; Costen, Marc; Haynes, Richard; Hughes, Edward; Pringle, Edward; Zambarakji, Hadi; Kanavos, Panos

    2016-11-01

    The direct cost to the National Health Service (NHS) in England of pars plana vitrectomy (PPV) is unknown since a bottom-up costing exercise has not been undertaken. Healthcare resource group (HRG) costing relies on a top-down approach. We aimed to quantify the direct cost of intermediate complexity PPV. Five NHS vitreoretinal units prospectively recorded all consumables, equipment and staff salaries during PPV undertaken for vitreomacular traction, epiretinal membrane and macular hole. Out-of-surgery costs between admission and discharge were estimated using a representative accounting method. The average patient time in theatre for 57 PPVs was 72 min. The average in-surgery cost for staff was £297, consumables £619, and equipment £82 (total £997). The average out-of-surgery costs were £260, including nursing and medical staff, other consumables, eye drops and hospitalisation. The total cost was therefore £1634, including 30 % overheads. This cost estimate was an under-estimate because it did not include out-of-theatre consumables or equipment. The average reimbursed HRG tariff was £1701. The cost of undertaking PPV of intermediate complexity is likely to be higher than the reimbursed tariff, except for hospitals with high throughput, where amortisation costs benefit from economies of scale. Although this research was set in England, the methodology may provide a useful template for other countries.

  1. Implementation status of self-assessment/peer-group discussion program: a bottom-up approach of monitoring/supervision in improving quality of health services.

    Science.gov (United States)

    Kafle, K K; Bhuju, G B; Karkee, S B; Prasad, R R; Shrestha, N; Shrestha, A D; Das, P L; Chataut, B D; Shrestha, A; Suvedi, B K

    2014-01-01

    Monitoring/supervision is an essential component for improving the quality of health services including rational use of medicines. A new bottom-up approach of monitoring/supervision consisting of self-assessment/ peer-group discussion was found to be effective in improving prescribing practices. The new strategy significantly improved the prescribing practices based on standard treatment guidelines. The government has implemented it as a Program in primary health care services of Nepal. This article aims to share the implementation status of the self-assessment/peer-group discussion Program for improving the prescribing practices of common health problems and availability of drugs in the district health system. Concurrent mixed research design was applied for data collection. The data were collected at different levels of health care system using in-depth interviews, participatory observations and documentary analysis. The Management Division, Department of Health Services implemented the Program in 2009-10 and the PHC Revitalization Division, DoHs is the implementation division since 2010-11. The Program comprised revision of participant's and trainer's manuals, training of trainers and prescribers, finalisation of health conditions and indicators, distribution of carbon copy prescription pads, and conduction of peer-group discussions.The Program was implemented in number of districts. The government made the policy decision to implement the Program for monitoring prescribing practices and the availability of free drugs in districts. However, it has covered only few districts and needs escalation to cover all 75 districts of the country.

  2. Perceived Effects of Pornography on the Couple Relationship: Initial Findings of Open-Ended, Participant-Informed, "Bottom-Up" Research.

    Science.gov (United States)

    Kohut, Taylor; Fisher, William A; Campbell, Lorne

    2017-02-01

    The current study adopted a participant-informed, "bottom-up," qualitative approach to identifying perceived effects of pornography on the couple relationship. A large sample (N = 430) of men and women in heterosexual relationships in which pornography was used by at least one partner was recruited through online (e.g., Facebook, Twitter, etc.) and offline (e.g., newspapers, radio, etc.) sources. Participants responded to open-ended questions regarding perceived consequences of pornography use for each couple member and for their relationship in the context of an online survey. In the current sample of respondents, "no negative effects" was the most commonly reported impact of pornography use. Among remaining responses, positive perceived effects of pornography use on couple members and their relationship (e.g., improved sexual communication, more sexual experimentation, enhanced sexual comfort) were reported frequently; negative perceived effects of pornography (e.g., unrealistic expectations, decreased sexual interest in partner, increased insecurity) were also reported, albeit with considerably less frequency. The results of this work suggest new research directions that require more systematic attention.

  3. Evaluating vehicle re-entrained road dust and its potential to deposit to Lake Tahoe: a bottom-up inventory approach.

    Science.gov (United States)

    Zhu, Dongzi; Kuhns, Hampden D; Gillies, John A; Gertler, Alan W

    2014-01-01

    Identifying hotspot areas impacted by emissions of dust from roadways is an essential step for mitigation. This paper develops a detailed road dust PM₁₀ emission inventory using a bottom-up approach and evaluates the potential for the dust to deposit to Lake Tahoe where it can affect water clarity. Previous studies of estimates of quantities of atmospheric deposition of fine sediment particles ("FSP", traffic demand model and GIS analysis was used to estimate the near field deposition of airborne particulate matter <16 μm, and assess the relationship between trip location and the potential magnitude of this source of atmospheric deposition to the lake. Approximately ~20 Mg year(-1) of PM₁₀ and ~36 Mg year(-1) Total Suspended Particulate (TSP) from roadway emissions of dust are estimated to reach the lake. We estimate that the atmospheric dry deposition of particles to the lake attributable to vehicle travel on paved roads is approximately 0.6% of the Total Maximum Daily Loadings (TMDL) of FSP that the lake can receive and still meet water quality standards. © 2013 Elsevier B.V. All rights reserved.

  4. Evolutionary Steps in the Emergence of Life Deduced from the Bottom-Up Approach and GADV Hypothesis (Top-Down Approach)

    Science.gov (United States)

    Ikehara, Kenji

    2016-01-01

    It is no doubt quite difficult to solve the riddle of the origin of life. So, firstly, I would like to point out the kinds of obstacles there are in solving this riddle and how we should tackle these difficult problems, reviewing the studies that have been conducted so far. After that, I will propose that the consecutive evolutionary steps in a timeline can be rationally deduced by using a common event as a juncture, which is obtained by two counter-directional approaches: one is the bottom-up approach through which many researchers have studied the origin of life, and the other is the top-down approach, through which I established the [GADV]-protein world hypothesis or GADV hypothesis on the origin of life starting from a study on the formation of entirely new genes in extant microorganisms. Last, I will describe the probable evolutionary process from the formation of Earth to the emergence of life, which was deduced by using a common event—the establishment of the first genetic code encoding [GADV]-amino acids—as a juncture for the results obtained from the two approaches. PMID:26821048

  5. High-Throughput Top-Down and Bottom-Up Processes for Forming Single-Nanotube Based Architectures for 3D Electronics

    Science.gov (United States)

    Kaul, Anupama B.; Megerian, Krikor G.; von Allmen, Paul; Kowalczyk, Robert; Baron, Richard

    2009-01-01

    We have developed manufacturable approaches to form single, vertically aligned carbon nanotubes, where the tubes are centered precisely, and placed within a few hundred nm of 1-1.5 micron deep trenches. These wafer-scale approaches were enabled by chemically amplified resists and inductively coupled Cryo-etchers for forming the 3D nanoscale architectures. The tube growth was performed using dc plasma-enhanced chemical vapor deposition (PECVD), and the materials used for the pre-fabricated 3D architectures were chemically and structurally compatible with the high temperature (700 C) PECVD synthesis of our tubes, in an ammonia and acetylene ambient. Tube characteristics were also engineered to some extent, by adjusting growth parameters, such as Ni catalyst thickness, pressure and plasma power during growth. Such scalable, high throughput top-down fabrication techniques, combined with bottom-up tube synthesis, should accelerate the development of PECVD tubes for applications such as interconnects, nano-electromechanical (NEMS), sensors or 3D electronics in general.

  6. Benchmarking Non-Hardware Balance-of-System (Soft) Costs for U.S. Photovoltaic Systems, Using a Bottom-Up Approach and Installer Survey - Second Edition

    Energy Technology Data Exchange (ETDEWEB)

    Friedman, B.; Ardani, K.; Feldman, D.; Citron, R.; Margolis, R.; Zuboy, J.

    2013-10-01

    This report presents results from the second U.S. Department of Energy (DOE) sponsored, bottom-up data-collection and analysis of non-hardware balance-of-system costs -- often referred to as 'business process' or 'soft' costs -- for U.S. residential and commercial photovoltaic (PV) systems. In service to DOE's SunShot Initiative, annual expenditure and labor-hour-productivity data are analyzed to benchmark 2012 soft costs related to (1) customer acquisition and system design (2) permitting, inspection, and interconnection (PII). We also include an in-depth analysis of costs related to financing, overhead, and profit. Soft costs are both a major challenge and a major opportunity for reducing PV system prices and stimulating SunShot-level PV deployment in the United States. The data and analysis in this series of benchmarking reports are a step toward the more detailed understanding of PV soft costs required to track and accelerate these price reductions.

  7. The bottom-up approach to defining life : deciphering the functional organization of biological cells via multi-objective representation of biological complexity from molecules to cells

    Directory of Open Access Journals (Sweden)

    Sathish ePeriyasamy

    2013-12-01

    Full Text Available In silico representation of cellular systems needs to represent the adaptive dynamics of biological cells, recognizing a cell’s multi-objective topology formed by spatially and temporally cohesive intracellular structures. The design of these models needs to address the hierarchical and concurrent nature of cellular functions and incorporate the ability to self-organise in response to transitions between healthy and pathological phases, and adapt accordingly. The functions of biological systems are constantly evolving, due to the ever changing demands of their environment. Biological systems meet these demands by pursuing objectives, aided by their constituents, giving rise to biological functions. A biological cell is organised into an objective/task hierarchy. These objective hierarchy corresponds to the nested nature of temporally cohesive structures and representing them will facilitate in studying pleiotropy and polygeny by modeling causalities propagating across multiple interconnected intracellular processes. Although biological adaptations occur in physiological, developmental and reproductive timescales, the paper is focused on adaptations that occur within physiological timescales, where the biomolecular activities contributing to functional organisation, play a key role in cellular physiology. The paper proposes a multi-scale and multi-objective modelling approach from the bottom-up by representing temporally cohesive structures for multi-tasking of intracellular processes. Further the paper characterises the properties and constraints that are consequential to the organisational and adaptive dynamics in biological cells.

  8. Evolutionary Steps in the Emergence of Life Deduced from the Bottom-Up Approach and GADV Hypothesis (Top-Down Approach

    Directory of Open Access Journals (Sweden)

    Kenji Ikehara

    2016-01-01

    Full Text Available It is no doubt quite difficult to solve the riddle of the origin of life. So, firstly, I would like to point out the kinds of obstacles there are in solving this riddle and how we should tackle these difficult problems, reviewing the studies that have been conducted so far. After that, I will propose that the consecutive evolutionary steps in a timeline can be rationally deduced by using a common event as a juncture, which is obtained by two counter-directional approaches: one is the bottom-up approach through which many researchers have studied the origin of life, and the other is the top-down approach, through which I established the [GADV]-protein world hypothesis or GADV hypothesis on the origin of life starting from a study on the formation of entirely new genes in extant microorganisms. Last, I will describe the probable evolutionary process from the formation of Earth to the emergence of life, which was deduced by using a common event—the establishment of the first genetic code encoding [GADV]-amino acids—as a juncture for the results obtained from the two approaches.

  9. Effects of bottom-up and top-down intervention principles in emergent literacy in children at risk of developmental dyslexia: a longitudinal study.

    Science.gov (United States)

    Helland, Turid; Tjus, Tomas; Hovden, Marit; Ofte, Sonja; Heimann, Mikael

    2011-01-01

    This longitudinal study focused on the effects of two different principles of intervention in children at risk of developing dyslexia from 5 to 8 years old. The children were selected on the basis of a background questionnaire given to parents and preschool teachers, with cognitive and functional magnetic resonance imaging results substantiating group differences in neuropsychological processes associated with phonology, orthography, and phoneme-grapheme correspondence (i.e., alphabetic principle). The two principles of intervention were bottom-up (BU), "from sound to meaning", and top-down (TD), "from meaning to sound." Thus, four subgroups were established: risk/BU, risk/TD, control/BU, and control/TD. Computer-based training took place for 2 months every spring, and cognitive assessments were performed each fall of the project period. Measures of preliteracy skills for reading and spelling were phonological awareness, working memory, verbal learning, and letter knowledge. Literacy skills were assessed by word reading and spelling. At project end the control group scored significantly above age norm, whereas the risk group scored within the norm. In the at-risk group, training based on the BU principle had the strongest effects on phonological awareness and working memory scores, whereas training based on the TD principle had the strongest effects on verbal learning, letter knowledge, and literacy scores. It was concluded that appropriate, specific, data-based intervention starting in preschool can mitigate literacy impairment and that interventions should contain BU training for preliteracy skills and TD training for literacy training.

  10. On the advantages of spring magnets compared to pure FePt: Strategy for rare-earth free permanent magnets following a bottom-up approach

    Energy Technology Data Exchange (ETDEWEB)

    Pousthomis, M.; Garnero, C. [Université de Toulouse, UMR 5215 INSA, CNRS, UPS, Laboratoire de Physique et Chimie des Nano-Objets, 135 avenue de Rangueil, F-31077 Toulouse Cedex 4 (France); Marcelot, C.G. [Université de Toulouse, UMR 5215 INSA, CNRS, UPS, Laboratoire de Physique et Chimie des Nano-Objets, 135 avenue de Rangueil, F-31077 Toulouse Cedex 4 (France); Centre d’Elaboration de Matériaux et d’Etudes Structurales, CEMES-CNRS, 29 rue Jeanne Marvig, B.P. 94347, 31055 Toulouse (France); Blon, T.; Cayez, S. [Université de Toulouse, UMR 5215 INSA, CNRS, UPS, Laboratoire de Physique et Chimie des Nano-Objets, 135 avenue de Rangueil, F-31077 Toulouse Cedex 4 (France); Cassignol, C.; Du, V.A.; Krispin, M. [Siemens AG, Corporate Technology, Munich (Germany); Arenal, R. [Transpyrenean Advanced Laboratory for Electron Microscopy (TALEM), INSA - INA, CNRS - Universidad de Zaragoza, 30155 Toulouse (France); Laboratorio de Microscopias Avanzadas (LMA), Instituto de Nanociencia de Aragon (INA), U. Zaragoza, C/Mariano Esquillor s/n, 50018 Zaragoza (Spain); Fundacion ARAID, 50018 Zaragoza (Spain); Soulantica, K.; Viau, G. [Université de Toulouse, UMR 5215 INSA, CNRS, UPS, Laboratoire de Physique et Chimie des Nano-Objets, 135 avenue de Rangueil, F-31077 Toulouse Cedex 4 (France); Lacroix, L.-M., E-mail: lmlacroi@insa-toulouse.fr [Université de Toulouse, UMR 5215 INSA, CNRS, UPS, Laboratoire de Physique et Chimie des Nano-Objets, 135 avenue de Rangueil, F-31077 Toulouse Cedex 4 (France); Transpyrenean Advanced Laboratory for Electron Microscopy (TALEM), INSA - INA, CNRS - Universidad de Zaragoza, 30155 Toulouse (France)

    2017-02-15

    Nanostructured magnets benefiting from efficient exchange-coupling between hard and soft grains represent an appealing approach for integrated miniaturized magnetic power sources. Using a bottom-up approach, nanostructured materials were prepared from binary assemblies of bcc FeCo and fcc FePt nanoparticles and compared with pure L1{sub 0}-FePt materials. The use of a bifunctional mercapto benzoic acid yields homogeneous assemblies of the two types of particles while reducing the organic matter amount. The 650 °C thermal annealing, mandatory to allow the L1{sub 0}-FePt phase transition, led to an important interdiffusion and thus decreased drastically the amount of soft phase present in the final composites. The analysis of recoil curves however evidenced the presence of an efficient interphase exchange coupling, which allows obtaining better magnetic performances than pure L1{sub 0} FePt materials, energy product above 100 kJ m{sup −3} being estimated for a Pt content of only 33%. These results clearly evidenced the interest of chemically grown nanoparticles for the preparation of performant spring-magnets, opening promising perspective for integrated subcentimetric magnets with optimized properties.

  11. Climate change, pink salmon, and the nexus between bottom-up and top-down forcing in the subarctic Pacific Ocean and Bering Sea.

    Science.gov (United States)

    Springer, Alan M; van Vliet, Gus B

    2014-05-06

    Climate change in the last century was associated with spectacular growth of many wild Pacific salmon stocks in the North Pacific Ocean and Bering Sea, apparently through bottom-up forcing linking meteorology to ocean physics, water temperature, and plankton production. One species in particular, pink salmon, became so numerous by the 1990s that they began to dominate other species of salmon for prey resources and to exert top-down control in the open ocean ecosystem. Information from long-term monitoring of seabirds in the Aleutian Islands and Bering Sea reveals that the sphere of influence of pink salmon is much larger than previously known. Seabirds, pink salmon, other species of salmon, and by extension other higher-order predators, are tightly linked ecologically and must be included in international management and conservation policies for sustaining all species that compete for common, finite resource pools. These data further emphasize that the unique 2-y cycle in abundance of pink salmon drives interannual shifts between two alternate states of a complex marine ecosystem.

  12. When top-down becomes bottom up: behaviour of hyperdense howler monkeys (Alouatta seniculus trapped on a 0.6 ha island.

    Directory of Open Access Journals (Sweden)

    Gabriela Orihuela

    Full Text Available Predators are a ubiquitous presence in most natural environments. Opportunities to contrast the behaviour of a species in the presence and absence of predators are thus rare. Here we report on the behaviour of howler monkey groups living under radically different conditions on two land-bridge islands in Lago Guri, Venezuela. One group of 6 adults inhabited a 190-ha island (Danto where they were exposed to multiple potential predators. This group, the control, occupied a home range of 23 ha and contested access to food resources with neighbouring groups in typical fashion. The second group, containing 6 adults, was isolated on a remote, predator-free 0.6 ha islet (Iguana offering limited food resources. Howlers living on the large island moved, fed and rested in a coherent group, frequently engaged in affiliative activities, rarely displayed agonistic behaviour and maintained intergroup spacing through howling. In contrast, the howlers on Iguana showed repulsion, as individuals spent most of their time spaced widely around the perimeter of the island. Iguana howlers rarely engaged in affiliative behaviour, often chased or fought with one another and were not observed to howl. These behaviors are interpreted as adjustments to the unrelenting deprivation associated with bottom-up limitation in a predator-free environment.

  13. Employment impacts of EU biofuels policy. Combining bottom-up technology information and sectoral market simulations in an input-output framework

    Energy Technology Data Exchange (ETDEWEB)

    Neuwahl, Frederik; Mongelli, Ignazio; Delgado, Luis [European Commission, Joint Research Centre, Institute for Prospective Technological Studies (IPTS), Edificio Expo, c/Inca Garcilaso s/n, 41072 Seville (Spain); Loeschel, Andreas [Centre for European Economic Research (ZEW), L7,1, 68161 Mannheim (Germany)

    2008-12-01

    This paper analyses the employment consequences of policies aimed to support biofuels in the European Union. The promotion of biofuel use has been advocated as a means to promote the sustainable use of natural resources and to reduce greenhouse gas emissions originating from transport activities on the one hand, and to reduce dependence on imported oil and thereby increase security of the European energy supply on the other hand. The employment impacts of increasing biofuels shares are calculated by taking into account a set of elements comprising the demand for capital goods required to produce biofuels, the additional demand for agricultural feedstock, higher fuel prices or reduced household budget in the case of price subsidisation, price effects ensuing from a hypothetical world oil price reduction linked to substitution in the EU market, and price impacts on agro-food commodities. The calculations refer to scenarios for the year 2020 targets as set out by the recent Renewable Energy Roadmap. Employment effects are assessed in an input-output framework taking into account bottom-up technology information to specify biofuels activities and linked to partial equilibrium models for the agricultural and energy sectors. The simulations suggest that biofuels targets on the order of 10-15% could be achieved without adverse net employment effects. (author)

  14. Bottom-Up Construction of Porous Organic Frameworks with Built-In TEMPO as a Cathode for Lithium-Sulfur Batteries.

    Science.gov (United States)

    Zhou, Baolong; Hu, Xiang; Zeng, Guang; Li, Shiwu; Wen, Zhenhai; Chen, Long

    2017-07-21

    Two redox-active porous organic frameworks (POFs) with a built-in radical moiety (TEMPO) and hierarchical porous structures were synthesized through a facile bottom-up strategy and studied as cathode materials for lithium-sulfur (Li-S) batteries. The sulfur loading in these two POFs reached 61 %, benefitting from their large pore volumes. Owing to the highly dense docking sites of TEMPO, sulfur could be covalently immobilized within the porous networks and efficiently inhibit the shuttle effect, thereby significantly improving the cycling performance. The composites TPE-TEMPO-POF-S (TPE=tetraphenylethene) deliver a capacity in excess of 470 mAh g-1 after 200 cycles with a coulombic efficiency of around 100 % at a current rate of 0.1 C. Furthermore, TEMPO-POFs with sulfur embedded showed excellent rate capability with limited capacity loss at rates of 0.1-1 C. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Fabricación de electrodos para control de transporte y alineamiento a micro y nanoescalas usando técnicas bottom-up y top-down

    Directory of Open Access Journals (Sweden)

    Darwin Rodríguez

    2014-12-01

    Full Text Available El continuo avance de aplicaciones en dispositivos de autoensamble, posicionamiento, sensores, actuadores, y que permitan controladamente la manipulación de micro y nanoestructuras, han generado amplio interés en el desarrollo de metodologías que permitan optimizar la fabricación de dispositivos para el control y manipulación a micro y nanoescalas. Este proyecto explora técnicas de fabricación de electrodos con el fin de encontrar una técnica óptima y reproducible. Se compara el rendimiento de cada técnica y se describen protocolos de limpieza y seguridad. Se diseñan e implementan tres geometrías para movilizar y posicionar micro y nanopartículas de hierro en una solución de aceite natural. Finalmente se generan campos eléctricos a partir de electroforesis, con el fin de encontrar la curva que describe el desplazamiento de las partículas con respecto al potencial aplicado. Estos resultados generan gran impacto en los actuales esfuerzos de fabricación bottom-up (controlando con campos la ubicación y la movilidad en dispositivos electrónicos. El hecho de fabricar geometría planar con electrodos genera la posibilidad de que se pueda integrar movimiento de partículas a los circuitos integrados que se fabrican en la actualidad.

  16. Synthesis of a Cementitious Material Nanocement Using Bottom-Up Nanotechnology Concept: An Alternative Approach to Avoid CO2 Emission during Production of Cement

    Directory of Open Access Journals (Sweden)

    Byung Wan Jo

    2014-01-01

    Full Text Available The world’s increasing need is to develop smart and sustainable construction material, which will generate minimal climate changing gas during their production. The bottom-up nanotechnology has established itself as a promising alternative technique for the production of the cementitious material. The present investigation deals with the chemical synthesis of cementitious material using nanosilica, sodium aluminate, sodium hydroxide, and calcium nitrate as reacting phases. The characteristic properties of the chemically synthesized nanocement were verified by the chemical composition analysis, setting time measurement, particle size distribution, fineness analysis, and SEM and XRD analyses. Finally, the performance of the nanocement was ensured by the fabrication and characterization of the nanocement based mortar. Comparing the results with the commercially available cement product, it is demonstrated that the chemically synthesized nanocement not only shows better physical and mechanical performance, but also brings several encouraging impacts to the society, including the reduction of CO2 emission and the development of sustainable construction material. A plausible reaction scheme has been proposed to explain the synthesis and the overall performances of the nanocement.

  17. A novel visual saliency detection method for infrared video sequences

    Science.gov (United States)

    Wang, Xin; Zhang, Yuzhen; Ning, Chen

    2017-12-01

    Infrared video applications such as target detection and recognition, moving target tracking, and so forth can benefit a lot from visual saliency detection, which is essentially a method to automatically localize the ;important; content in videos. In this paper, a novel visual saliency detection method for infrared video sequences is proposed. Specifically, for infrared video saliency detection, both the spatial saliency and temporal saliency are considered. For spatial saliency, we adopt a mutual consistency-guided spatial cues combination-based method to capture the regions with obvious luminance contrast and contour features. For temporal saliency, a multi-frame symmetric difference approach is proposed to discriminate salient moving regions of interest from background motions. Then, the spatial saliency and temporal saliency are combined to compute the spatiotemporal saliency using an adaptive fusion strategy. Besides, to highlight the spatiotemporal salient regions uniformly, a multi-scale fusion approach is embedded into the spatiotemporal saliency model. Finally, a Gestalt theory-inspired optimization algorithm is designed to further improve the reliability of the final saliency map. Experimental results demonstrate that our method outperforms many state-of-the-art saliency detection approaches for infrared videos under various backgrounds.

  18. Culturally divergent responses to mortality salience.

    Science.gov (United States)

    Ma-Kellams, Christine; Blascovich, Jim

    2011-08-01

    Two experiments compared the effects of death thoughts, or mortality salience, on European and Asian Americans. Research on terror management theory has demonstrated that in Western cultural groups, individuals typically employ self-protective strategies in the face of death-related thoughts. Given fundamental East-West differences in self-construal (i.e., the independent vs. interdependent self), we predicted that members of Eastern cultural groups would affirm other people, rather than defend and affirm the self, after encountering conditions of mortality salience. We primed European Americans and Asian Americans with either a death or a control prime and examined the effect of this manipulation on attitudes about a person who violates cultural norms (Study 1) and on attributions about the plight of an innocent victim (Study 2). Mortality salience promoted culturally divergent responses, leading European Americans to defend the self and Asian Americans to defend other people.

  19. Image retrieval based on multi-instance saliency model

    Science.gov (United States)

    Wan, Shouhong; Jin, Peiquan; Yue, Lihua; Yan, Li

    2017-07-01

    Existing methods for visual saliency based image retrieval typically aim at single instance image. However, without any prior knowledge, the content of single instance image is ambiguous and these methods cannot effectively reflect the object of interest. In this paper, we propose a novel image retrieval framework based on multi-instance saliency model. First, the feature saliency is computed based on global contrast, local contrast and sparsity, and the synthesize saliency map is obtained by using Multi-instance Learning (MIL) algorithm to dynamically weight the feature saliency. Then we employ a fuzzy region-growth algorithm on the synthesize saliency map to extract the saliency object. We finally extract color and texture feature as the retrieval feature and measure feature similarity by Euclidean distance. In the experiments, the proposed method can achieve higher multi-instance image retrieval accuracy than the other single instance image retrieval methods based on saliency model.

  20. Object recognition with hierarchical discriminant saliency networks

    Directory of Open Access Journals (Sweden)

    Sunhyoung eHan

    2014-09-01

    Full Text Available The benefits of integrating attention and object recognition are investigated. While attention is frequently modeled as pre-processor for recognition, we investigate the hypothesis that attention is an intrinsic component of recognition and vice-versa. This hypothesis is tested with a recognitionmodel, the hierarchical discriminant saliency network (HDSN, whose layers are top-down saliency detectors, tuned for a visual class according to the principles of discriminant saliency. The HDSN has two possible implementations. In a biologically plausible implementation, all layers comply with the standard neurophysiological model of visual cortex, with sub-layers of simple and complex units that implement a combination of filtering, divisive normalization, pooling, and non-linearities. In a neuralnetwork implementation, all layers are convolutional and implement acombination of filtering, rectification, and pooling. The rectificationis performed with a parametric extension of the now popular rectified linearunits (ReLUs, whose parameters can be tuned for the detection of targetobject classes. This enables a number of functional enhancementsover neural network models that lack a connection to saliency, including optimal feature denoising mechanisms for recognition, modulation ofsaliency responses by the discriminant power of the underlying features,and the ability to detect both feature presence and absence.In either implementation, each layer has a precise statistical interpretation, and all parameters are tuned by statistical learning. Each saliency detection layer learns more discriminant saliency templates than its predecessors and higher layers have larger pooling fields. This enables the HDSN to simultaneously achieve high selectivity totarget object classes and invariance. The resulting performance demonstrates benefits for all the functional enhancements of the HDSN.

  1. An efficient visual saliency detection model based on Ripplet transform

    Indian Academy of Sciences (India)

    In day-to-day life, one can find ample applications of saliency detection in image and video processing. This paper ... The global and local saliency maps are computed based on the global probability density distribution and feature distribution of local areas, which are combined together to get the final saliency map.

  2. Electron-beam lithography and molecular liftoff for directed attachment of DNA nanostructures on silicon: top-down meets bottom-up.

    Science.gov (United States)

    Pillers, Michelle; Goss, Valerie; Lieberman, Marya

    2014-06-17

    CONSPECTUS: Our work on lithographic patterning of DNA nanostructures was inspired by a collaboration on molecular electronic devices known as quantum-dot cellular automata or QCA. QCA is a paradigm for computation in which information is transmitted and processed through the interaction of coupled electrical charges or magnetic dipoles. We began to explore the idea of molecular scale QCA and found that ab initio methods, a thermodynamic Ising model, and larger scale circuit design work suggested that circuits that did computationally interesting things could function at room temperature if made from molecular QCA cells of chemically reasonable design. But how could the QCA cells be patterned to form the complex arrays needed for computationally interesting circuitry, and how could those arrays of molecular circuitry be integrated with conventional electronic inputs and outputs? Top-down methods lacked the spatial resolution and high level of parallelism needed to make molecular circuits. Bottom-up chemical synthesis lacked the ability to fabricate arbitrary and heterogeneous structures tens to hundreds of nanometers in size. Chemical self-assembly at the time could produce structures in the right size scale, but was limited to homogeneous arrays. A potential solution to this conundrum was just being demonstrated in the late 1990s and early 2000s: DNA nanostructures self-assembled from oligonucleotides, whose high information density could handle the creation of arbitrary structures and chemical inhomogeneity. Our group became interested in whether DNA nanostructures could function as self-assembling circuit boards for electrical or magnetic QCA systems. This Account focuses on what we learned about the interactions of DNA nanostructures with silicon substrates and, particularly, on how electron-beam lithography could be used to direct the binding of DNA nanostructures on a variety of functional substrates.

  3. The control of automatic imitation based on bottom-up and top-down cues to animacy: insights from brain and behavior.

    Science.gov (United States)

    Klapper, André; Ramsey, Richard; Wigboldus, Daniël; Cross, Emily S

    2014-11-01

    Humans automatically imitate other people's actions during social interactions, building rapport and social closeness in the process. Although the behavioral consequences and neural correlates of imitation have been studied extensively, little is known about the neural mechanisms that control imitative tendencies. For example, the degree to which an agent is perceived as human-like influences automatic imitation, but it is not known how perception of animacy influences brain circuits that control imitation. In the current fMRI study, we examined how the perception and belief of animacy influence the control of automatic imitation. Using an imitation-inhibition paradigm that involves suppressing the tendency to imitate an observed action, we manipulated both bottom-up (visual input) and top-down (belief) cues to animacy. Results show divergent patterns of behavioral and neural responses. Behavioral analyses show that automatic imitation is equivalent when one or both cues to animacy are present but reduces when both are absent. By contrast, right TPJ showed sensitivity to the presence of both animacy cues. Thus, we demonstrate that right TPJ is biologically tuned to control imitative tendencies when the observed agent both looks like and is believed to be human. The results suggest that right TPJ may be involved in a specialized capacity to control automatic imitation of human agents, rather than a universal process of conflict management, which would be more consistent with generalist theories of imitative control. Evidence for specialized neural circuitry that "controls" imitation offers new insight into developmental disorders that involve atypical processing of social information, such as autism spectrum disorders.

  4. Top-down/bottom-up description of electricity sector for Switzerland using the GEM-E3 computable general equilibrium model

    Energy Technology Data Exchange (ETDEWEB)

    Krakowski, R. A

    2006-06-15

    Participation of the Paul Scherrer Institute (PSI) in the advancement and extension of the multi-region, Computable General Equilibrium (CGE) model GEM-E3 (CES/KUL, 2002) focused primarily on two top-level facets: a) extension of the model database and model calibration, particularly as related to the second component of this study, which is; b) advancement of the dynamics of innovation and investment, primarily through the incorporation of Exogenous Technical Learning (ETL) into he Bottom-Up (BU, technology-based) part of the dynamic upgrade; this latter activity also included the completion of the dynamic coupling of the BU description of the electricity sector with the 'Top-Down' (TD, econometric) description of the economy inherent to the GEM-E3 CGE model. The results of this two- component study are described in two parts that have been combined in this single summary report: Part I describes the methodology and gives illustrative results from the BUTD integration, as well as describing the approach to and giving preliminary results from incorporating an ETL description into the BU component of the overall model; Part II reports on the calibration component of task in terms of: a) formulating a BU technology database for Switzerland based on previous work; incorporation of that database into the GEM-E3 model; and calibrating the BU database with the TD database embodied in the (Swiss) Social Accounting Matrix (SAM). The BUTD coupling along with the ETL incorporation described in Part I represent the major effort embodied in this investigation, but this effort could not be completed without the calibration preamble reported herein as Part II. A brief summary of the scope of each of these key study components is given. (author)

  5. Setting an ecological baseline prior to the bottom-up establishment of a marine protected area in Santorini island, Aegean Sea

    Directory of Open Access Journals (Sweden)

    M. SALOMIDI

    2016-08-01

    Full Text Available Since 2010, a bottom-up initiative has been launched in Santorini Island (Aegean Sea, Eastern Mediterranean for the establishment of the first fully-protected marine protected area in the Cyclades, aiming at improving fisheries and enhancing responsible recreational uses at sea. Following discussions with local small-scale fishers and divers, two sites along the southern and southeastern coasts of the island were suggested as suitable to this end. In 2012, a baseline study was conducted at these areas to assess their state and provide an ecological snapshot that would enable sound designation and monitoring. Several ad hoc indices and metrics were applied, taking into account structural and functional features of the upper infralittoral algae and Posidonia oceanica beds. An integrated assessment of the infralittoral fish assemblages and their associated benthic communities was also performed. Our most important findings were: (i the low total fish biomass and the absence of adult top predators, indicating overfishing; (ii the overgrazing effects of the overabundant alien herbivore spinefoot fishes (Siganus spp., as reflected by the abnormal structure of the algal communities; (iii the scarcity of signs of pollution or other direct anthropogenic pressures, as indicated by the good environmental status of the P. oceanica meadows and the upper infralittoral vegetation; and (iv the presence of a rich diversity of species and habitats, especially along the Akrotiri Peninsula and the wider volcanic Caldera. These findings provide useful insights on strengths and weaknesses of the study area and are discussed together with their implications for protection and management.

  6. Energetic Bottomup in the Low Countries. Energy transition from the bottom-up. On Happy energetic civilians, Solar and wind cooperatives, New utility companies; Energieke BottomUp in Lage Landen. De Energietransitie van Onderaf. Over Vrolijke energieke burgers, Zon- en windcooperaties, Nieuwe nuts

    Energy Technology Data Exchange (ETDEWEB)

    Schwencke, A.M.

    2012-08-15

    This essay is an outline of the 'energy transition from the bottom-up'. Leading questions are: (1) what are the actual initiatives; (2) who is involved; (3) how does one work (organization, business models); (4) why are people active in this field; (5) what good is it; (6) what is the aim? The essay is based on public information sources (websites, blogs, publications) and interviews with people involved [Dutch] Dit essay is een verkenning van de 'energietransitie van onderaf'. Leidende vragen zijn: (1) om wat voor initiatieven gaat het nu eigenlijk?; (2) wie zijn daarbij betrokken?; (3) hoe gaat men te werk (organisatie, business modellen)?; (4) waarom is men er op die manier mee bezig?; (5) Zet het zoden aan de dijk?; (6) Waar beweegt het naar toe? Het essay baseert zich op openbare bronnen (websites, blogs, publicaties) en gesprekken met mensen uit het veld.

  7. Previsão top-down ou bottom-up? Impacto nos níveis de erro e de estoques de segurança Top-down or bottom-up forecasting? Impact on error and safety inventory levels

    Directory of Open Access Journals (Sweden)

    Peter Wanke

    2008-08-01

    Full Text Available A literatura de operações permanece sem concluir sobre a melhor abordagem em previsão de vendas: se da previsão dos dados agregados para os itens individuais (denominada abordagem top-down, ou se dos itens individuais para os dados agregados (denominada bottom-up. Nesse manuscrito são apresentados os resultados para a média e a variância dos erros de previsão com amortecimento exponencial nessas abordagens, considerando-se o caso em que a fração da série individual nas vendas agregados é estocástica. Por meio da geração de números aleatórios, são confirmados dois principais impactos na variância do erro de previsão, apresentados em pesquisas anteriores: efeitos portfólio e ancoragem. Os impactos também são avaliados em termos dos erros de previsão e do dimensionamento de estoques de segurança.The operations literature remains inconclusive about the most adequate forecasting approach - top-down or bottom-up. This paper presents analytical results for mean values and variances of forecasting errors with exponential smoothing under these approaches. The share of the series in the total aggregate data is considered stochastic. Based on the generation of random numbers, two major impacts are confirmed on the variance of forecasting error, which were presented in previous papers, namely, portfolio and anchorage effects. The impacts are also evaluated in terms of forecasting bias and safety inventory levels.

  8. The protection pyramid approach : A contribution to the protection of internally displaced persons by combining bottom up coping mechanisms and top down protection strategies into a partnership approach to protection

    NARCIS (Netherlands)

    Janssen, Laura

    2017-01-01

    In het huidige debat over de bescherming van Intern Ontheemde Mensen (IDPs) spelen twee groepen actoren een rol. Enerzijds de ontheemden zelf (Bottom Up actoren genoemd), anderzijds de Staat, niet-Statelijke actoren en andere hulpverleners (Top Down actoren). Van oudsher wordt er meer aandacht

  9. Enhancing the wettability of high aspect-ratio through-silicon vias lined with LPCVD silicon nitride or PE-ALD titanium nitride for void-free bottom-up copper electroplating

    NARCIS (Netherlands)

    Saadaoui, M.; Zeijl, H. van; Wien, W.H.A.; Pham, H.T.M.; Kwakernaak, C.; Knoops, H.C.M.; Erwin Kessels, W.M.M.; Sanden, R.M.C.M. van de; Voogt, F.C.; Roozeboom, F.; Sarro, P.M.

    2011-01-01

    One of the critical steps toward producing void-free and uniform bottom-up copper electroplating in high aspect-ratio (AR) through-silicon vias (TSVs) is the ability of the copper electrolyte to spontaneously flow through the entire depth of the via. This can be accomplished by reducing the

  10. Visualization of neural networks using saliency maps

    DEFF Research Database (Denmark)

    Mørch, Niels J.S.; Kjems, Ulrik; Hansen, Lars Kai

    1995-01-01

    The saliency map is proposed as a new method for understanding and visualizing the nonlinearities embedded in feedforward neural networks, with emphasis on the ill-posed case, where the dimensionality of the input-field by far exceeds the number of examples. Several levels of approximations...

  11. Referent Salience Affects Second Language Article Use

    Science.gov (United States)

    Trenkic, Danijela; Pongpairoj, Nattama

    2013-01-01

    The effect of referent salience on second language (L2) article production in real time was explored. Thai (-articles) and French (+articles) learners of English described dynamic events involving two referents, one visually cued to be more salient at the point of utterance formulation. Definiteness marking was made communicatively redundant with…

  12. Image saliency by isocentric curvedness and color

    NARCIS (Netherlands)

    Valenti, R.; Sebe, N.; Gevers, T.

    2009-01-01

    In this paper we propose a novel computational method to infer visual saliency in images. The method is based on the idea that salient objects should have local characteristics that are different than the rest of the scene, being edges, color or shape. By using a novel operator, these

  13. Benchmarking Non-Hardware Balance-of-System (Soft) Costs for U.S. Photovoltaic Systems Using a Bottom-Up Approach and Installer Survey

    Energy Technology Data Exchange (ETDEWEB)

    Ardani, Kristen [National Renewable Energy Lab. (NREL), Golden, CO (United States); Margolis, Robert [National Renewable Energy Lab. (NREL), Golden, CO (United States); Feldman, David [National Renewable Energy Lab. (NREL), Golden, CO (United States); Ong, Sean [National Renewable Energy Lab. (NREL), Golden, CO (United States); Barbose, Galen [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Wiser, Ryan [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2012-11-01

    This report presents results from the first U.S. Department of Energy (DOE) sponsored, bottom-up data-collection and analysis of non-hardware balance-of-system costs—often referred to as “business process” or “soft” costs—for residential and commercial photovoltaic (PV) systems. Annual expenditure and labor-hour-productivity data are analyzed to benchmark 2010 soft costs related to the DOE priority areas of (1) customer acquisition; (2) permitting, inspection, and interconnection; (3) installation labor; and (4) installer labor for arranging third-party financing. Annual expenditure and labor-hour data were collected from 87 PV installers. After eliminating outliers, the survey sample consists of 75 installers, representing approximately 13% of all residential PV installations and 4% of all commercial installations added in 2010. Including assumed permitting fees, in 2010 the average soft costs benchmarked in this analysis total $1.50/W for residential systems (ranging from $0.66/W to $1.66/W between the 20th and 80th percentiles). For commercial systems, the median 2010 benchmarked soft costs (including assumed permitting fees) are $0.99/W for systems smaller than 250 kW (ranging from $0.51/W to $1.45/W between the 20th and 80th percentiles) and $0.25/W for systems larger than 250 kW (ranging from $0.17/W to $0.78/W between the 20th and 80th percentiles). Additional soft costs not benchmarked in the present analysis (e.g., installer profit, overhead, financing, and contracting) are significant and would add to these figures. The survey results provide a benchmark for measuring—and helping to accelerate—progress over the next decade toward achieving the DOE SunShot Initiative’s soft-cost-reduction targets. We conclude that the selected non-hardware business processes add considerable cost to U.S. PV systems, constituting 23% of residential PV system price, 17% of small commercial system price, and 5% of large commercial system price (in 2010

  14. A Statistical Method for Estimating Missing GHG Emissions in Bottom-Up Inventories: The Case of Fossil Fuel Combustion in Industry in the Bogota Region, Colombia

    Science.gov (United States)

    Jimenez-Pizarro, R.; Rojas, A. M.; Pulido-Guio, A. D.

    2012-12-01

    The development of environmentally, socially and financially suitable greenhouse gas (GHG) mitigation portfolios requires detailed disaggregation of emissions by activity sector, preferably at the regional level. Bottom-up (BU) emission inventories are intrinsically disaggregated, but although detailed, they are frequently incomplete. Missing and erroneous activity data are rather common in emission inventories of GHG, criteria and toxic pollutants, even in developed countries. The fraction of missing and erroneous data can be rather large in developing country inventories. In addition, the cost and time for obtaining or correcting this information can be prohibitive or can delay the inventory development. This is particularly true for regional BU inventories in the developing world. Moreover, a rather common practice is to disregard or to arbitrarily impute low default activity or emission values to missing data, which typically leads to significant underestimation of the total emissions. Our investigation focuses on GHG emissions by fossil fuel combustion in industry in the Bogota Region, composed by Bogota and its adjacent, semi-rural area of influence, the Province of Cundinamarca. We found that the BU inventories for this sub-category substantially underestimate emissions when compared to top-down (TD) estimations based on sub-sector specific national fuel consumption data and regional energy intensities. Although both BU inventories have a substantial number of missing and evidently erroneous entries, i.e. information on fuel consumption per combustion unit per company, the validated energy use and emission data display clear and smooth frequency distributions, which can be adequately fitted to bimodal log-normal distributions. This is not unexpected as industrial plant sizes are typically log-normally distributed. Moreover, our statistical tests suggest that industrial sub-sectors, as classified by the International Standard Industrial Classification (ISIC

  15. Frontotemporal oxyhemoglobin dynamics predict performance accuracy of dance simulation gameplay: temporal characteristics of top-down and bottom-up cortical activities.

    Science.gov (United States)

    Ono, Yumie; Nomoto, Yasunori; Tanaka, Shohei; Sato, Keisuke; Shimada, Sotaro; Tachibana, Atsumichi; Bronner, Shaw; Noah, J Adam

    2014-01-15

    We utilized the high temporal resolution of functional near-infrared spectroscopy to explore how sensory input (visual and rhythmic auditory cues) are processed in the cortical areas of multimodal integration to achieve coordinated motor output during unrestricted dance simulation gameplay. Using an open source clone of the dance simulation video game, Dance Dance Revolution, two cortical regions of interest were selected for study, the middle temporal gyrus (MTG) and the frontopolar cortex (FPC). We hypothesized that activity in the FPC would indicate top-down regulatory mechanisms of motor behavior; while that in the MTG would be sustained due to bottom-up integration of visual and auditory cues throughout the task. We also hypothesized that a correlation would exist between behavioral performance and the temporal patterns of the hemodynamic responses in these regions of interest. Results indicated that greater temporal accuracy of dance steps positively correlated with persistent activation of the MTG and with cumulative suppression of the FPC. When auditory cues were eliminated from the simulation, modifications in cortical responses were found depending on the gameplay performance. In the MTG, high-performance players showed an increase but low-performance players displayed a decrease in cumulative amount of the oxygenated hemoglobin response in the no music condition compared to that in the music condition. In the FPC, high-performance players showed relatively small variance in the activity regardless of the presence of auditory cues, while low-performance players showed larger differences in the activity between the no music and music conditions. These results suggest that the MTG plays an important role in the successful integration of visual and rhythmic cues and the FPC may work as top-down control to compensate for insufficient integrative ability of visual and rhythmic cues in the MTG. The relative relationships between these cortical areas indicated

  16. The impact of napping on memory for future-relevant stimuli: Prioritization among multiple salience cues.

    Science.gov (United States)

    Bennion, Kelly A; Payne, Jessica D; Kensinger, Elizabeth A

    2016-06-01

    Prior research has demonstrated that sleep enhances memory for future-relevant information, including memory for information that is salient due to emotion, reward, or knowledge of a later memory test. Although sleep has been shown to prioritize information with any of these characteristics, the present study investigates the novel question of how sleep prioritizes information when multiple salience cues exist. Participants encoded scenes that were future-relevant based on emotion (emotional vs. neutral), reward (rewarded vs. unrewarded), and instructed learning (intentionally vs. incidentally encoded), preceding a delay consisting of a nap, an equivalent time period spent awake, or a nap followed by wakefulness (to control for effects of interference). Recognition testing revealed that when multiple dimensions of future relevance co-occur, sleep prioritizes top-down, goal-directed cues (instructed learning, and to a lesser degree, reward) over bottom-up, stimulus-driven characteristics (emotion). Further, results showed that these factors interact; the effect of a nap on intentionally encoded information was especially strong for neutral (relative to emotional) information, suggesting that once one cue for future relevance is present, there are diminishing returns with additional cues. Sleep may binarize information based on whether it is future-relevant or not, preferentially consolidating memory for the former category. Potential neural mechanisms underlying these selective effects and the implications of this research for educational and vocational domains are discussed. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

  17. The Culture War and Issue Salience

    DEFF Research Database (Denmark)

    Wroe, Andrew; Ashbee, Edward; Gosling, Amanda

    2014-01-01

    by Republicans and Democrats, conservatives and liberals, evangelicals and non-evangelicals, and frequent and infrequent worshippers alike. While the first finding offers support for the saliency hypothesis and the culture war thesis, the second challenges the idea that Americans are engaged in a war over......Despite much talk of a culture war, scholars continue to argue over whether the American public is divided on cultural and social issues. Some of the most prominent work in this area, such as Fiorina's Culture War?, has rejected the idea. However, this work has in turn been criticized for focussing...... only on the distribution of attitudes within the American public and ignoring the possibility that the culture war may also be driven by the increasing strength with which sections of the population hold their opinions. This paper tests the strength, or saliency, hypothesis using individual-level over...

  18. Top-down and bottom-up aerosol–cloud closure: towards understanding sources of uncertainty in deriving cloud shortwave radiative flux

    Directory of Open Access Journals (Sweden)

    K. J. Sanchez

    2017-08-01

    Full Text Available Top-down and bottom-up aerosol–cloud shortwave radiative flux closures were conducted at the Mace Head Atmospheric Research Station in Galway, Ireland, in August 2015. This study is part of the BACCHUS (Impact of Biogenic versus Anthropogenic emissions on Clouds and Climate: towards a Holistic UnderStanding European collaborative project, with the goal of understanding key processes affecting aerosol–cloud shortwave radiative flux closures to improve future climate predictions and develop sustainable policies for Europe. Instrument platforms include ground-based unmanned aerial vehicles (UAVs1 and satellite measurements of aerosols, clouds and meteorological variables. The ground-based and airborne measurements of aerosol size distributions and cloud condensation nuclei (CCN concentration were used to initiate a 1-D microphysical aerosol–cloud parcel model (ACPM. UAVs were equipped for a specific science mission, with an optical particle counter for aerosol distribution profiles, a cloud sensor to measure cloud extinction or a five-hole probe for 3-D wind vectors. UAV cloud measurements are rare and have only become possible in recent years through the miniaturization of instrumentation. These are the first UAV measurements at Mace Head. ACPM simulations are compared to in situ cloud extinction measurements from UAVs to quantify closure in terms of cloud shortwave radiative flux. Two out of seven cases exhibit sub-adiabatic vertical temperature profiles within the cloud, which suggests that entrainment processes affect cloud microphysical properties and lead to an overestimate of simulated cloud shortwave radiative flux. Including an entrainment parameterization and explicitly calculating the entrainment fraction in the ACPM simulations both improved cloud-top radiative closure. Entrainment reduced the difference between simulated and observation-derived cloud-top shortwave radiative flux (δRF by between 25 and 60 W m−2. After

  19. Comparing Top-down and Bottom-up Estimates of Methane Emissions across Multiple U.S. Basins Provides Insights into National Oil and Gas Emissions and Mitigation Strategies

    Science.gov (United States)

    Hamburg, S.; Alvarez, R.; Lyon, D. R.; Zavala-Araiza, D.

    2016-12-01

    Several recent studies quantified regional methane emissions in U.S. oil and gas (O&G) basins using top-down approaches such as airborne mass balance measurements. These studies apportioned total methane emissions to O&G based on hydrocarbon ratios or subtracting bottom-up estimates of other sources. In most studies, top-down estimates of O&G methane emissions exceeded bottom-up emission inventories. An exception is the Barnett Shale Coordinated Campaign, which found agreement between aircraft mass balance estimates and a custom emission inventory. Reconciliation of Barnett Shale O&G emissions depended on two key features: 1) matching the spatial domains of top-down and bottom-up estimates, and 2) accounting for fat-tail sources in site-level emission factors. We construct spatially explicit custom emission inventories for domains with top-down O&G emission estimates in eight major U.S. oil and gas production basins using a variety of data sources including a spatially-allocated U.S. EPA Greenhouse Gas Inventory, the EPA Greenhouse Gas Reporting Program, state emission inventories, and recently published measurement studies. A comparison of top-down and our bottom-up estimates of O&G emissions constrains the gap between these approaches and elucidates regional variability in production-normalized loss rates. A comparison of component-level and site-level emission estimates of production sites in the Barnett Shale region - where comprehensive activity data and emissions estimates are available - indicates that abnormal process conditions contribute about 20% of regional O&G emissions. Combining these two analyses provides insights into the relative importance of different equipment, processes, and malfunctions to emissions in each basin. These data allow us to estimate the U.S. O&G supply chain loss rate, recommend mitigation strategies to reduce emissions from existing infrastructure, and discuss how a similar approach can be applied internationally.

  20. A bottom-up perspective on leadership of collaborative innovation in the public sector:The social construction of leadership for disadvantaged city districts in The City of Copenhagen

    OpenAIRE

    Hansen, Jesper Rohr

    2014-01-01

    The thesis investigates how new forms of public leadership can contribute to solving complex problems in today’s welfare societies through innovation. A bottom-up type of leadership for collaborative innovation addressing wicked problems is theorised, displaying a social constructive process approach to leadership; a theoretical model emphasises that leadership emerges through social processes of recognition. Leadership is recognised by utilising the uncertainty of a wicked problem and innova...

  1. Top-down and bottom-up approaches to motor skill assessment of children: are child-report and parent-report perceptions predictive of children's performance-based assessment results?

    Science.gov (United States)

    Kennedy, Johanna; Brown, Ted; Stagnitti, Karen

    2013-01-01

    BACKGROUND/ AIM: Therapists use different types of tests, scales, and instruments to assess children's motor skills, including those classified as being top-down and bottom-up. The aim of the study was to investigate the ability of measures of children's motor skill performance from the perspectives of children and parents (a type of top-down assessment) to predict children's performance-based motor ability test results (a type of bottom-up assessment). A convenience sample of 38 children and parents was recruited from Victoria, Australia. Motor skill performance was evaluated from a top-down perspective using the Physical Self-Description Questionnaire (PSDQ) and the Movement Assessment Battery for Children--Second Edition (MABC-2) Checklist to measure children's and parents' perspectives respectively. Motor skill performance was also evaluated from a bottom-up approach using the Bruininks-Oseretsky Test of Motor Proficiency--Second Edition (BOT-2). Data were analyzed using multiple linear regression analysis to determine whether the PSDQ or MABC-2 Checklist was predictive of the children's BOT-2 performance results. Two predictive relationships were identified based on parents' perspectives, where the total score of the MABC-2 Checklist was found to be a significant predictor of the BOT-2 Manual Coordination motor composite score, accounting for 8.35% of its variance, and the BOT-2 Strength and Agility motor composite score, accounting for 11.6% of its variance. No predictive relationships were identified between the children's self-report PSDQ perspectives and the BOT-2 performance scores. Therapists are encouraged to utilize a combination of top-down and bottom-up approaches and purposefully to seek parents' and children's perspectives when evaluating children's motor skill performance.

  2. Reconciling Basin-Scale Top-Down and Bottom-Up Methane Emission Measurements for Onshore Oil and Gas Development: Cooperative Research and Development Final Report, CRADA Number CRD-14-572

    Energy Technology Data Exchange (ETDEWEB)

    Heath, Garvin A. [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2017-12-04

    The overall objective of the Research Partnership to Secure Energy for America (RPSEA)-funded research project is to develop independent estimates of methane emissions using top-down and bottom-up measurement approaches and then to compare the estimates, including consideration of uncertainty. Such approaches will be applied at two scales: basin and facility. At facility scale, multiple methods will be used to measure methane emissions of the whole facility (controlled dual tracer and single tracer releases, aircraft-based mass balance and Gaussian back-trajectory), which are considered top-down approaches. The bottom-up approach will sum emissions from identified point sources measured using appropriate source-level measurement techniques (e.g., high-flow meters). At basin scale, the top-down estimate will come from boundary layer airborne measurements upwind and downwind of the basin, using a regional mass balance model plus approaches to separate atmospheric methane emissions attributed to the oil and gas sector. The bottom-up estimate will result from statistical modeling (also known as scaling up) of measurements made at selected facilities, with gaps filled through measurements and other estimates based on other studies. The relative comparison of the bottom-up and top-down estimates made at both scales will help improve understanding of the accuracy of the tested measurement and modeling approaches. The subject of this CRADA is NREL's contribution to the overall project. This project resulted from winning a competitive solicitation no. RPSEA RFP2012UN001, proposal no. 12122-95, which is the basis for the overall project. This Joint Work Statement (JWS) details the contributions of NREL and Colorado School of Mines (CSM) in performance of the CRADA effort.

  3. A visual saliency based method for vehicle logo detection

    Science.gov (United States)

    Zhang, Fan; Shen, Yiping; Chang, Hongxing

    2013-07-01

    This paper presents a novel method based on visual saliency and template matching for detecting vehicle logo from images captured by cross-road cameras. To detect the logo, such method first generates a saliency map based on the modified Itti's saliency model, and then obtains regions of interest (ROI) by thresholding the saliency map, at last performs an edge-based template matching to locate the logo. Experiments on more than 2400 images validate both high accuracy and efficiency of the proposed method, and demonstrates our method suitable for real-time application.

  4. An efficient visual saliency detection model based on Ripplet transform

    Indian Academy of Sciences (India)

    A Diana Andrushia

    Abstract. Even though there have been great advancements in computer vision tasks, the development of human visual attention models is still not well investigated. In day-to-day life, one can find ample applications of saliency detection in image and video processing. This paper presents an efficient visual saliency ...

  5. Intrinsic religiosity reduces intergroup hostility under mortality salience

    NARCIS (Netherlands)

    De Zavala, Agnieszka Golec; Cichocka, Aleksandra; Orehek, Edward; Abdollahi, Abdolhossein

    Results of three studies indicate that intrinsic religiosity and mortality salience interact to predict intergroup hostility. Study 1, conducted among 200 American Christians and Jews, reveals that under mortality salience, intrinsic (but not extrinsic or quest) religiosity is related to decreased

  6. Morality salience increases adherence to salient norms and values

    NARCIS (Netherlands)

    Gailliot, M.T.; Stillman, T.F.; Schmeichel, B.J.; Maner, J.K.; Plant, E.A.

    2008-01-01

    Four studies indicate that mortality salience increases adherence to social norms and values, but only when cultural norms and values are salient. In Study 1, mortality salience coupled with a reminder about cultural values of egalitarianism reduced prejudice toward Blacks among non-Black

  7. Color edge saliency boosting using natural image statistics

    NARCIS (Netherlands)

    Rojas Vigo, D.; van de Weijer, J.; Gevers, T.

    2010-01-01

    State of the art methods for image matching, content-based retrieval and recognition use local features. Most of these still exploit only the luminance information for detection. The color saliency boosting algorithm has provided an efficient method to exploit the saliency of color edges based on

  8. Decision salience signals in posterior cingulate cortex

    Directory of Open Access Journals (Sweden)

    Sarah eHeilbronner

    2011-04-01

    Full Text Available Despite its phylogenetic antiquity and clinical importance, the posterior cingulate cortex (CGp remains an enigmatic nexus of attention, memory, motivation, and decision making. Here we show that CGp neurons track decision salience—the degree to which an option differs from a standard—but not the subjective value of a decision. To do this, we recorded the spiking activity of CGp neurons in monkeys choosing between options varying in reward-related risk, delay to reward, and social outcomes, each of which varied in level of decision salience. Firing rates were higher when monkeys chose the risky option, consistent with their risk-seeking preferences, but were also higher when monkeys chose the delayed and social options, contradicting their preferences. Thus, across decision contexts, neuronal activity was uncorrelated with how much monkeys valued a given option, as inferred from choice. Instead, neuronal activity signaled the deviation of the chosen option from the standard, independently of how it differed. The observed decision salience signals suggest a role for CGp in the flexible allocation of neural resources to motivationally significant information, akin to the role of attention in selective processing of sensory inputs.

  9. Improving Saliency Models by Predicting Human Fixation Patches

    KAUST Repository

    Dubey, Rachit

    2015-04-16

    There is growing interest in studying the Human Visual System (HVS) to supplement and improve the performance of computer vision tasks. A major challenge for current visual saliency models is predicting saliency in cluttered scenes (i.e. high false positive rate). In this paper, we propose a fixation patch detector that predicts image patches that contain human fixations with high probability. Our proposed model detects sparse fixation patches with an accuracy of 84 % and eliminates non-fixation patches with an accuracy of 84 % demonstrating that low-level image features can indeed be used to short-list and identify human fixation patches. We then show how these detected fixation patches can be used as saliency priors for popular saliency models, thus, reducing false positives while maintaining true positives. Extensive experimental results show that our proposed approach allows state-of-the-art saliency methods to achieve better prediction performance on benchmark datasets.

  10. Object detection system based on multimodel saliency maps

    Science.gov (United States)

    Guo, Ya'nan; Luo, Chongfan; Ma, Yide

    2017-03-01

    Detection of visually salient image regions is extensively applied in computer vision and computer graphics, such as object detection, adaptive compression, and object recognition, but any single model always has its limitations to various images, so in our work, we establish a method based on multimodel saliency maps to detect the object, which intelligently absorbs the merits of various individual saliency detection models to achieve promising results. The method can be roughly divided into three steps: in the first step, we propose a decision-making system to evaluate saliency maps obtained by seven competitive methods and merely select the three most valuable saliency maps; in the second step, we introduce heterogeneous PCNN algorithm to obtain three prime foregrounds; and then a self-designed nonlinear fusion method is proposed to merge these saliency maps; at last, the adaptive improved and simplified PCNN model is used to detect the object. Our proposed method can constitute an object detection system for different occasions, which requires no training, is simple, and highly efficient. The proposed saliency fusion technique shows better performance over a broad range of images and enriches the applicability range by fusing different individual saliency models, this proposed system is worthy enough to be called a strong model. Moreover, the proposed adaptive improved SPCNN model is stemmed from the Eckhorn's neuron model, which is skilled in image segmentation because of its biological background, and in which all the parameters are adaptive to image information. We extensively appraise our algorithm on classical salient object detection database, and the experimental results demonstrate that the aggregation of saliency maps outperforms the best saliency model in all cases, yielding highest precision of 89.90%, better recall rates of 98.20%, greatest F-measure of 91.20%, and lowest mean absolute error value of 0.057, the value of proposed saliency evaluation

  11. Development Of A Web Service And Android 'APP' For The Distribution Of Rainfall Data. A Bottom-Up Remote Sensing Data Mining And Redistribution Project In The Age Of The 'Web 2.0'

    Science.gov (United States)

    Mantas, Vasco M.; Pereira, A. J. S. C.; Liu, Zhong

    2013-12-01

    A project was devised to develop a set of freely available applications and web services that can (1) simplify access from Mobile Devices to TOVAS data and (2) support the development of new datasets through data repackaging and mash-up. The bottom-up approach enables the multiplication of new services, often of limited direct interest to the organizations that produces the original, global datasets, but significant to small, local users. Through this multiplication of services, the development cost is transferred to the intermediate or end users and the entire process is made more efficient, even allowing new players to use the data in innovative ways.

  12. Tracking salience in young people: A psychometric field test of the Aberrant Salience Inventory (ASI).

    Science.gov (United States)

    Raballo, Andrea; Cicero, David C; Kerns, John G; Sanna, Sara; Pintus, Mirra; Agartz, Ingrid; Pintus, Elisa; Corrias, Irene; Lai, Veronica; Petretto, Donatella Rita; Carta, Mauro G; Preti, Antonio

    2017-07-18

    To explore the prevalence of Aberrant Salience (AS, an alleged experiential feature of psychosis-proneness) in Italian young people and corroborate the transcultural validity of the Aberrant Salience Inventory (ASI). Young adults attending an Italian university (n = 649) underwent serial evaluations with the ASI together with psychometric proxies for help seeking General Health Questionnaire and attenuated positive and negative symptoms Schizotypal Personality Questionnaire (SPQ). The distribution of ASI scores was explored with latent class analysis (LCA). Reliability of the Italian version of the ASI (I-ASI) was acceptable for all subscales (ordinal alpha >.70). Concurrent validity was in the expected direction, with higher correlations with measures of attenuated positive symptoms vs negative symptoms of psychosis (Steigers' z test, P ASI as a tool for the real-world characterization of people with vulnerability to psychosis, such as symptomatic help seekers with clinical high-risk states. © 2017 John Wiley & Sons Australia, Ltd.

  13. Salience of Somatosensory Stimulus Modulating External-to-Internal Orienting Attention

    Directory of Open Access Journals (Sweden)

    Jiaxin Peng

    2017-08-01

    Full Text Available Shifting between one’s external and internal environments involves orienting attention. Studies on differentiating subprocesses associated with external-to-internal orienting attention are limited. This study aimed to reveal the characteristics of the disengagement, shifting and reengagement subprocesses by using somatosensory external stimuli and internally generated images. Study participants were to perceive nociceptive external stimuli (External Low (EL or External High (EH induced by electrical stimulations (50 ms followed by mentally rehearsing learned subnociceptive images (Internal Low (IL and Internal High (IH. Behavioral responses and EEG signals of the participants were recorded. The three significant components elicited were: fronto-central negativity (FCN; 128–180 ms, fronto-central P2 (200–260 ms, and central P3 (320–380 ms, which reflected the three subprocesses, respectively. Differences in the FCN and P2 amplitudes during the orienting to the subnociceptive images revealed only in the EH but not EL stimulus condition that are new findings. The results indicated that modulations of the disengagement and shifting processes only happened if the external nociceptive stimuli were of high salience and the external-to-internal incongruence was large. The reengaging process reflected from the amplitude of P3 correlated significantly with attenuation of the pain intensity felt from the external nociceptive stimuli. These findings suggested that the subprocesses underlying external-to-internal orienting attention serve different roles. Disengagement subprocess tends to be stimulus dependent, which is bottom-up in nature. Shifting and reengagement tend to be top-down subprocesses, which taps on cognitive control. This subprocess may account for the attenuation effects on perceived pain intensity after orienting attention.

  14. Salience Effects in the North-West of England

    Directory of Open Access Journals (Sweden)

    Sandra Jansen

    2014-06-01

    Full Text Available The question of how we can define salience, what properties it includes and how we can quantify it have been discussed widely over the past thirty years but we still have more questions than answers about this phenomenon, e. g. not only how salience arises, but also how we can define it. However, despite the lack of a clear definition, salience is often taken into account as an explanatory factor in language change. The scientific discourse on salience has in most cases revolved around phonetic features, while hardly any variables on other linguistic levels have been investigated in terms of their salience. Hence, one goal of this paper is to argue for an expanded view of salience in the sociolinguistic context. This article investigates the variation and change of two groups of variables in Carlisle, an urban speech community in the north west of England. I analyse the variable (th and in particular the replacement of /θ/ with [f] which is widely known as th-fronting. The use of three discourse markers is also examined. Both groups of features will then be discussed in the light of sociolinguistic salience.

  15. What drives farmers to make top-down or bottom-up adaptation to climate change and fluctuations? A comparative study on 3 cases of apple farming in Japan and South Africa.

    Science.gov (United States)

    Fujisawa, Mariko; Kobayashi, Kazuhiko; Johnston, Peter; New, Mark

    2015-01-01

    Agriculture is one of the most vulnerable sectors to climate change. Farmers have been exposed to multiple stressors including climate change, and they have managed to adapt to those risks. The adaptation actions undertaken by farmers and their decision making are, however, only poorly understood. By studying adaptation practices undertaken by apple farmers in three regions: Nagano and Kazuno in Japan and Elgin in South Africa, we categorize the adaptation actions into two types: farmer initiated bottom-up adaptation and institution led top-down adaptation. We found that the driver which differentiates the type of adaptation likely adopted was strongly related to the farmers' characteristics, particularly their dependence on the institutions, e.g. the farmers' cooperative, in selling their products. The farmers who rely on the farmers' cooperative for their sales are likely to adopt the institution-led adaptation, whereas the farmers who have established their own sales channels tend to start innovative actions by bottom-up. We further argue that even though the two types have contrasting features, the combinations of the both types of adaptations could lead to more successful adaptation particularly in agriculture. This study also emphasizes that more farm-level studies for various crops and regions are warranted to provide substantial feedbacks to adaptation policy.

  16. A framework for assessing inter-individual variability in pharmacokinetics using virtual human populations and integrating general knowledge of physical chemistry, biology, anatomy, physiology and genetics: A tale of 'bottom-up' vs 'top-down' recognition of covariates.

    Science.gov (United States)

    Jamei, Masoud; Dickinson, Gemma L; Rostami-Hodjegan, Amin

    2009-01-01

    An increasing number of failures in clinical stages of drug development have been related to the effects of candidate drugs in a sub-group of patients rather than the 'average' person. Expectation of extreme effects or lack of therapeutic effects in some subgroups following administration of similar doses requires a full understanding of the issue of variability and the importance of identifying covariates that determine the exposure to the drug candidates in each individual. In any drug development program the earlier these covariates are known the better. An important component of the drive to decrease this failure rate in drug development involves attempts to use physiologically-based pharmacokinetics 'bottom-up' modeling and simulation to optimize molecular features with respect to the absorption, distribution, metabolism and elimination (ADME) processes. The key element of this approach is the separation of information on the system (i.e. human body) from that of the drug (e.g. physicochemical characteristics determining permeability through membranes, partitioning to tissues, binding to plasma proteins or affinities toward certain enzymes and transporter proteins) and the study design (e.g. dose, route and frequency of administration, concomitant drugs and food). In this review, the classical 'top-down' approach in covariate recognition is compared with the 'bottom-up' paradigm. The determinants and sources of inter-individual variability in different stages of drug absorption, distribution, metabolism and excretion are discussed in detail. Further, the commonly known tools for simulating ADME properties are introduced.

  17. What drives farmers to make top-down or bottom-up adaptation to climate change and fluctuations? A comparative study on 3 cases of apple farming in Japan and South Africa.

    Directory of Open Access Journals (Sweden)

    Mariko Fujisawa

    Full Text Available Agriculture is one of the most vulnerable sectors to climate change. Farmers have been exposed to multiple stressors including climate change, and they have managed to adapt to those risks. The adaptation actions undertaken by farmers and their decision making are, however, only poorly understood. By studying adaptation practices undertaken by apple farmers in three regions: Nagano and Kazuno in Japan and Elgin in South Africa, we categorize the adaptation actions into two types: farmer initiated bottom-up adaptation and institution led top-down adaptation. We found that the driver which differentiates the type of adaptation likely adopted was strongly related to the farmers' characteristics, particularly their dependence on the institutions, e.g. the farmers' cooperative, in selling their products. The farmers who rely on the farmers' cooperative for their sales are likely to adopt the institution-led adaptation, whereas the farmers who have established their own sales channels tend to start innovative actions by bottom-up. We further argue that even though the two types have contrasting features, the combinations of the both types of adaptations could lead to more successful adaptation particularly in agriculture. This study also emphasizes that more farm-level studies for various crops and regions are warranted to provide substantial feedbacks to adaptation policy.

  18. Baking a mass-spectrometry data PIE with McMC and simulated annealing: predicting protein post-translational modifications from integrated top-down and bottom-up data.

    Science.gov (United States)

    Jefferys, Stuart R; Giddings, Morgan C

    2011-03-15

    Post-translational modifications are vital to the function of proteins, but are hard to study, especially since several modified isoforms of a protein may be present simultaneously. Mass spectrometers are a great tool for investigating modified proteins, but the data they provide is often incomplete, ambiguous and difficult to interpret. Combining data from multiple experimental techniques-especially bottom-up and top-down mass spectrometry-provides complementary information. When integrated with background knowledge this allows a human expert to interpret what modifications are present and where on a protein they are located. However, the process is arduous and for high-throughput applications needs to be automated. This article explores a data integration methodology based on Markov chain Monte Carlo and simulated annealing. Our software, the Protein Inference Engine (the PIE) applies these algorithms using a modular approach, allowing multiple types of data to be considered simultaneously and for new data types to be added as needed. Even for complicated data representing multiple modifications and several isoforms, the PIE generates accurate modification predictions, including location. When applied to experimental data collected on the L7/L12 ribosomal protein the PIE was able to make predictions consistent with manual interpretation for several different L7/L12 isoforms using a combination of bottom-up data with experimentally identified intact masses. Software, demo projects and source can be downloaded from http://pie.giddingslab.org/

  19. Mediatization

    DEFF Research Database (Denmark)

    Hjarvard, Stig

    2017-01-01

    Mediatization research shares media effects studies' ambition of answering the difficult questions with regard to whether and how media matter and influence contemporary culture and society. The two approaches nevertheless differ fundamentally in that mediatization research seeks answers...... to these general questions by distinguishing between two concepts: mediation and mediatization. The media effects tradition generally considers the effects of the media to be a result of individuals being exposed to media content, i.e. effects are seen as an outcome of mediated communication. Mediatization....... From the perspective of mediatization research, the most important effect of the media stems from their embeddedness in culture and society....

  20. Complete Workflow for Analysis of Histone Post-translational Modifications Using Bottom-up Mass Spectrometry: From Histone Extraction to Data Analysis.

    Science.gov (United States)

    Sidoli, Simone; Bhanu, Natarajan V; Karch, Kelly R; Wang, Xiaoshi; Garcia, Benjamin A

    2016-05-17

    Nucleosomes are the smallest structural unit of chromatin, composed of 147 base pairs of DNA wrapped around an octamer of histone proteins. Histone function is mediated by extensive post-translational modification by a myriad of nuclear proteins. These modifications are critical for nuclear integrity as they regulate chromatin structure and recruit enzymes involved in gene regulation, DNA repair and chromosome condensation. Even though a large part of the scientific community adopts antibody-based techniques to characterize histone PTM abundance, these approaches are low throughput and biased against hypermodified proteins, as the epitope might be obstructed by nearby modifications. This protocol describes the use of nano liquid chromatography (nLC) and mass spectrometry (MS) for accurate quantification of histone modifications. This method is designed to characterize a large variety of histone PTMs and the relative abundance of several histone variants within single analyses. In this protocol, histones are derivatized with propionic anhydride followed by digestion with trypsin to generate peptides of 5 - 20 aa in length. After digestion, the newly exposed N-termini of the histone peptides are derivatized to improve chromatographic retention during nLC-MS. This method allows for the relative quantification of histone PTMs spanning four orders of magnitude.

  1. Mortality salience increases adherence to salient norms and values.

    Science.gov (United States)

    Gailliot, Matthew T; Stillman, Tyler F; Schmeichel, Brandon J; Maner, Jon K; Plant, E Ashby

    2008-07-01

    Four studies indicate that mortality salience increases adherence to social norms and values, but only when cultural norms and values are salient. In Study 1, mortality salience coupled with a reminder about cultural values of egalitarianism reduced prejudice toward Blacks among non-Black participants. In Studies 2 through 4, a mortality salience induction (e.g., walking through a cemetery) increased self-reported and actual helping behavior only when the cultural value of helping was salient. These results suggest that people may adhere to norms and values so as to manage awareness of death.

  2. Properties of V1 neurons tuned to conjunctions of visual features: application of the V1 saliency hypothesis to visual search behavior.

    Directory of Open Access Journals (Sweden)

    Li Zhaoping

    Full Text Available From a computational theory of V1, we formulate an optimization problem to investigate neural properties in the primary visual cortex (V1 from human reaction times (RTs in visual search. The theory is the V1 saliency hypothesis that the bottom-up saliency of any visual location is represented by the highest V1 response to it relative to the background responses. The neural properties probed are those associated with the less known V1 neurons tuned simultaneously or conjunctively in two feature dimensions. The visual search is to find a target bar unique in color (C, orientation (O, motion direction (M, or redundantly in combinations of these features (e.g., CO, MO, or CM among uniform background bars. A feature singleton target is salient because its evoked V1 response largely escapes the iso-feature suppression on responses to the background bars. The responses of the conjunctively tuned cells are manifested in the shortening of the RT for a redundant feature target (e.g., a CO target from that predicted by a race between the RTs for the two corresponding single feature targets (e.g., C and O targets. Our investigation enables the following testable predictions. Contextual suppression on the response of a CO-tuned or MO-tuned conjunctive cell is weaker when the contextual inputs differ from the direct inputs in both feature dimensions, rather than just one. Additionally, CO-tuned cells and MO-tuned cells are often more active than the single feature tuned cells in response to the redundant feature targets, and this occurs more frequently for the MO-tuned cells such that the MO-tuned cells are no less likely than either the M-tuned or O-tuned neurons to be the most responsive neuron to dictate saliency for an MO target.

  3. Are persistent delusions in schizophrenia associated with aberrant salience?

    Directory of Open Access Journals (Sweden)

    Rafeef Abboud

    2016-06-01

    Conclusion: These findings do not support the hypothesis that persistent delusions are related to aberrant motivational salience processing in TRS patients. However, they do support the view that patients with schizophrenia have impaired reward learning.

  4. Mortality salience increases personal relevance of the norm of reciprocity.

    Science.gov (United States)

    Schindler, Simon; Reinhard, Marc-André; Stahlberg, Dagmar

    2012-10-01

    Research on terror management theory found evidence that people under mortality salience strive to live up to salient cultural norms and values, like egalitarianism, pacifism, or helpfulness. A basic, strongly internalized norm in most human societies is the norm of reciprocity: people should support those who supported them (i.e., positive reciprocity), and people should injure those who injured them (i.e., negative reciprocity), respectively. In an experiment (N = 98; 47 women, 51 men), mortality salience overall significantly increased personal relevance of the norm of reciprocity (M = 4.45, SD = 0.65) compared to a control condition (M = 4.19, SD = 0.59). Specifically, under mortality salience there was higher motivation to punish those who treated them unfavourably (negative norm of reciprocity). Unexpectedly, relevance of the norm of positive reciprocity remained unaffected by mortality salience. Implications and limitations are discussed.

  5. Inhibition Underlies the Effect of High Need for Closure on Cultural Closed-Mindedness under Mortality Salience

    OpenAIRE

    Dmitrij Agroskin; Eva Jonas; Johannes Klackl; Mike Prentice

    2016-01-01

    The hypothesis that people respond to reminders of mortality with closed-minded, ethnocentric attitudes has received extensive empirical support, largely from research in the Terror Management Theory (TMT) tradition. However, the basic motivational and neural processes that underlie this effect remain largely hypothetical. According to recent neuropsychological theorizing, mortality salience (MS) effects on cultural closed-mindedness may be mediated by activity in the behavioral inhibition sy...

  6. Intrinsic religiosity reduces intergroup hostility under mortality salience

    OpenAIRE

    Golec de Zavala, Agnieszka; Cichocka, Aleksandra; Orehek, Edward; Abdollahi, Abdolhossein

    2012-01-01

    WOS:000304393300007 (Nº de Acesso Web of Science) “Prémio Científico ISCTE-IUL 2013” Results of three studies indicate that intrinsic religiosity and mortality salience interact to predict intergroup hostility. Study 1, conducted among 200 American Christians and Jews, reveals that under mortality salience, intrinsic (but not extrinsic or quest) religiosity is related to decreased support for aggressive counterterrorism. Study 2, conducted among 148 Muslims in Iran, demonstrates that in...

  7. "Bottom-up" in situ proteomic differentiation of human and non-human haemoglobins for forensic purposes by matrix-assisted laser desorption/ionization time-of-flight tandem mass spectrometry.

    Science.gov (United States)

    Kamanna, S; Henry, J; Voelcker, N; Linacre, A; Kirkbride, K P

    2017-11-30

    The detection and identification of human blood on crime-related items are of particular relevance to many investigations because shed blood can provide evidence of violent contact between individuals. However, for any detection and identification technique, specificity is a critical performance characteristic to assess; that is, whether the technique has the capability to differentiate between human blood (which usually is of relevance to a criminal investigation) and non-human blood (which usually would not be associated with a crime but may be detected incidentally). Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) approaches using "top-down" (detection of intact proteins) and "bottom-up" (detection of tryptic peptide markers) were used to detect and identify haemoglobin in blood from humans and from a range of Australian native mammals; the technique could be carried out directly on blood stains without the need to extract proteins (i.e., in situ measurement). Imaging of haemoglobin was achieved in bloodied fingermarks, including those that had been enhanced using two "industry standard" fingermark enhancement processes. Differentiation of intact haemoglobin proteins in human and non-human blood using "top-down" MALDI-TOF-MS was difficult. However, in situ "bottom-up" approaches using tandem mass spectrometry (MS/MS) and de novo sequencing of tryptic digest peptides allowed unambiguous differentiation. Imaging mass spectrometry of human haemoglobin, even when it was mixed with animal blood, was achieved in bloodied fingermarks that had been enhanced using two common processes (staining with Amido Black or dusted with magnetic powder) and "lifted" using adhesive tape. The MALDI-TOF-MS-based in situ "bottom-up" proteomic methodology described here shows great promise for the detection of human blood and even imaging of blood in bloodied fingermarks. The approach is sensitive, can differentiate between human blood and

  8. Multi-polarimetric textural distinctiveness for outdoor robotic saliency detection

    Science.gov (United States)

    Haider, S. A.; Scharfenberger, C.; Kazemzadeh, F.; Wong, A.; Clausi, D. A.

    2015-01-01

    Mobile robots that rely on vision, for navigation and object detection, use saliency approaches to identify a set of potential candidates to recognize. The state of the art in saliency detection for mobile robotics often rely upon visible light imaging, using conventional camera setups, to distinguish an object against its surroundings based on factors such as feature compactness, heterogeneity and/or homogeneity. We are demonstrating a novel multi- polarimetric saliency detection approach which uses multiple measured polarization states of a scene. We leverage the light-material interaction known as Fresnel reflections to extract rotationally invariant multi-polarimetric textural representations to then train a high dimensional sparse texture model. The multi-polarimetric textural distinctiveness is characterized using a conditional probability framework based on the sparse texture model which is then used to determine the saliency at each pixel of the scene. It was observed that through the inclusion of additional polarized states into the saliency analysis, we were able to compute noticeably improved saliency maps in scenes where objects are difficult to distinguish from their background due to color intensity similarities between the object and its surroundings.

  9. Removing label ambiguity in learning-based visual saliency estimation.

    Science.gov (United States)

    Li, Jia; Xu, Dong; Gao, Wen

    2012-04-01

    Visual saliency is a useful clue to depict visually important image/video contents in many multimedia applications. In visual saliency estimation, a feasible solution is to learn a "feature-saliency" mapping model from the user data obtained by manually labeling activities or eye-tracking devices. However, label ambiguities may also arise due to the inaccurate and inadequate user data. To process the noisy training data, we propose a multi-instance learning to rank approach for visual saliency estimation. In our approach, the correlations between various image patches are incorporated into an ordinal regression framework. By iteratively refining a ranking model and relabeling the image patches with respect to their mutual correlations, the label ambiguities can be effectively removed from the training data. Consequently, visual saliency can be effectively estimated by the ranking model, which can pop out real targets and suppress real distractors. Extensive experiments on two public image data sets show that our approach outperforms 11 state-of-the-art methods remarkably in visual saliency estimation.

  10. Disgust sensitivity predicts defensive responding to mortality salience.

    Science.gov (United States)

    Kelley, Nicholas J; Crowell, Adrienne L; Tang, David; Harmon-Jones, Eddie; Schmeichel, Brandon J

    2015-10-01

    Disgust protects the physical self. The present authors suggest that disgust also contributes to the protection of the psychological self by fostering stronger defensive reactions to existential concerns. To test this idea, 3 studies examined the link between disgust sensitivity and defensive responses to mortality salience or "terror management" processes (Greenberg, Solomon, & Pyszczynski, 1997). Each study included an individual difference measure of disgust sensitivity, a manipulation of mortality salience, and a dependent measure of defensive responding. In Study 1, disgust sensitivity predicted increases in worldview defense in the mortality salience condition but not in the control condition. In Study 2, disgust sensitivity predicted increases in optimistic perceptions of the future in the mortality salience condition but not in the control condition. In Study 3, disgust sensitivity predicted reductions in delay discounting for those in the mortality salience condition such that those higher in disgust sensitivity discounted the future less. This pattern did not occur in the control condition. These findings highlight disgust sensitivity as a key to understanding reactions to mortality salience, and they support the view that disgust-related responses protect against both physical (e.g., noxious substances) and psychological threats. (c) 2015 APA, all rights reserved).

  11. Bridging the Gap between the Nanometer-Scale Bottom-Up and Micrometer-Scale Top-Down Approaches for Site-Defined InP/InAs Nanowires.

    Science.gov (United States)

    Zhang, Guoqiang; Rainville, Christophe; Salmon, Adrian; Takiguchi, Masato; Tateno, Kouta; Gotoh, Hideki

    2015-11-24

    This work presents a method that bridges the gap between the nanometer-scale bottom-up and micrometer-scale top-down approaches for site-defined nanostructures, which has long been a significant challenge for applications that require low-cost and high-throughput manufacturing processes. We realized the bridging by controlling the seed indium nanoparticle position through a self-assembly process. Site-defined InP nanowires were then grown from the indium-nanoparticle array in the vapor-liquid-solid mode through a "seed and grow" process. The nanometer-scale indium particles do not always occupy the same locations within the micrometer-scale open window of an InP exposed substrate due to the scale difference. We developed a technique for aligning the nanometer-scale indium particles on the same side of the micrometer-scale window by structuring the surface of a misoriented InP (111)B substrate. Finally, we demonstrated that the developed method can be used to grow a uniform InP/InAs axial-heterostructure nanowire array. The ability to form a heterostructure nanowire array with this method makes it possible to tune the emission wavelength over a wide range by employing the quantum confinement effect and thus expand the application of this technology to optoelectronic devices. Successfully pairing a controllable bottom-up growth technique with a top-down substrate preparation technique greatly improves the potential for the mass-production and widespread adoption of this technology.

  12. Efficient Research Design: Using Value-of-Information Analysis to Estimate the Optimal Mix of Top-down and Bottom-up Costing Approaches in an Economic Evaluation alongside a Clinical Trial.

    Science.gov (United States)

    Wilson, Edward C F; Mugford, Miranda; Barton, Garry; Shepstone, Lee

    2016-04-01

    In designing economic evaluations alongside clinical trials, analysts are frequently faced with alternative methods of collecting the same data, the extremes being top-down ("gross costing") and bottom-up ("micro-costing") approaches. A priori, bottom-up approaches may be considered superior to top-down approaches but are also more expensive to collect and analyze. In this article, we use value-of-information analysis to estimate the efficient mix of observations on each method in a proposed clinical trial. By assigning a prior bivariate distribution to the 2 data collection processes, the predicted posterior (i.e., preposterior) mean and variance of the superior process can be calculated from proposed samples using either process. This is then used to calculate the preposterior mean and variance of incremental net benefit and hence the expected net gain of sampling. We apply this method to a previously collected data set to estimate the value of conducting a further trial and identifying the optimal mix of observations on drug costs at 2 levels: by individual item (process A) and by drug class (process B). We find that substituting a number of observations on process A for process B leads to a modest £ 35,000 increase in expected net gain of sampling. Drivers of the results are the correlation between the 2 processes and their relative cost. This method has potential use following a pilot study to inform efficient data collection approaches for a subsequent full-scale trial. It provides a formal quantitative approach to inform trialists whether it is efficient to collect resource use data on all patients in a trial or on a subset of patients only or to collect limited data on most and detailed data on a subset. © The Author(s) 2016.

  13. IMI - Oral biopharmaceutics tools project - Evaluation of bottom-up PBPK prediction success part 3: Identifying gaps in system parameters by analysing In Silico performance across different compound classes.

    Science.gov (United States)

    Darwich, Adam S; Margolskee, Alison; Pepin, Xavier; Aarons, Leon; Galetin, Aleksandra; Rostami-Hodjegan, Amin; Carlert, Sara; Hammarberg, Maria; Hilgendorf, Constanze; Johansson, Pernilla; Karlsson, Eva; Murphy, Dónal; Tannergren, Christer; Thörn, Helena; Yasin, Mohammed; Mazuir, Florent; Nicolas, Olivier; Ramusovic, Sergej; Xu, Christine; Pathak, Shriram M; Korjamo, Timo; Laru, Johanna; Malkki, Jussi; Pappinen, Sari; Tuunainen, Johanna; Dressman, Jennifer; Hansmann, Simone; Kostewicz, Edmund; He, Handan; Heimbach, Tycho; Wu, Fan; Hoft, Carolin; Pang, Yan; Bolger, Michael B; Huehn, Eva; Lukacova, Viera; Mullin, James M; Szeto, Ke X; Costales, Chester; Lin, Jian; McAllister, Mark; Modi, Sweta; Rotter, Charles; Varma, Manthena; Wong, Mei; Mitra, Amitava; Bevernage, Jan; Biewenga, Jeike; Van Peer, Achiel; Lloyd, Richard; Shardlow, Carole; Langguth, Peter; Mishenzon, Irina; Nguyen, Mai Anh; Brown, Jonathan; Lennernäs, Hans; Abrahamsson, Bertil

    2017-01-01

    Three Physiologically Based Pharmacokinetic software packages (GI-Sim, Simcyp® Simulator, and GastroPlus™) were evaluated as part of the Innovative Medicine Initiative Oral Biopharmaceutics Tools project (OrBiTo) during a blinded "bottom-up" anticipation of human pharmacokinetics. After data analysis of the predicted vs. measured pharmacokinetics parameters, it was found that oral bioavailability (Foral) was underpredicted for compounds with low permeability, suggesting improper estimates of intestinal surface area, colonic absorption and/or lack of intestinal transporter information. Foral was also underpredicted for acidic compounds, suggesting overestimation of impact of ionisation on permeation, lack of information on intestinal transporters, or underestimation of solubilisation of weak acids due to less than optimal intestinal model pH settings or underestimation of bile micelle contribution. Foral was overpredicted for weak bases, suggesting inadequate models for precipitation or lack of in vitro precipitation information to build informed models. Relative bioavailability was underpredicted for both high logP compounds as well as poorly water-soluble compounds, suggesting inadequate models for solubility/dissolution, underperforming bile enhancement models and/or lack of biorelevant solubility measurements. These results indicate areas for improvement in model software, modelling approaches, and generation of applicable input data. However, caution is required when interpreting the impact of drug-specific properties in this exercise, as the availability of input parameters was heterogeneous and highly variable, and the modellers generally used the data "as is" in this blinded bottom-up prediction approach. Copyright © 2016 Elsevier B.V. All rights reserved.

  14. Saliency modulates global perception in simultanagnosia.

    Science.gov (United States)

    Huberle, Elisabeth; Karnath, Hans-Otto

    2010-08-01

    Patients with parieto-occipital brain damage may show simultanagnosia, a selective impairment in the simultaneous perception and integration of multiple objects (global perception) with normal recognition of individual objects. Recent findings in patients with simultanagnosia indicate improved global perception at smaller spatial distances between local elements of hierarchical organized complex visual arrays. Global perception thus does not appear to be an all-or-nothing phenomenon but can be modified by the spatial relationship between local elements. The present study aimed to define characteristics of a general principle that accounts for improved global perception of hierarchically organized complex visual arrays in patients with simultanagnosia with respect to the spatial properties of local elements. In detail, we investigated the role of the number and size of the local elements as well as their relationship with each other for the global perception. The findings indicate that global perception increases independently of the size of the global object and depends on the spatial relationship between the local elements and the global object. The results further argue against the possibility of a restriction in the attended or perceived area in simultanagnosia, in the sense that the integration of local elements into a global scene is impaired if a certain spatial "field of view" is exceeded. A possible explanation for these observations might be a shift from global to local saliency in simultanagnosia.

  15. Bottom-up tailoring of photonic nanofibers

    DEFF Research Database (Denmark)

    Balzer, Frank; Madsen, Morten; Frese, Ralf

    2008-01-01

    Aligned ensembles of nanoscopic nanofibers from organic molecules such as para-phenylenes for photonic applications can be fabricated by self-assembled molecular growth on a suited dielectric substrate. Epitaxy together with alignment due to electric surface fields determines the growth directions...

  16. Mobile Handsets from the Bottom Up

    DEFF Research Database (Denmark)

    Wallis, Cara; Linchuan Qiu, Jack; Ling, Richard

    2013-01-01

    that have been brought to the premises through both legitimate and questionable means. The clientele of such establishments also engage in their own bricolage: sharing mobile phones, changing out SIM cards, “beeping,” reconfiguring the handset, and engaging in other creative uses not necessarily conceived......-income, largely immigrant communities in cities in the developed world....

  17. Milk bottom-up proteomics: method optimisation.

    Directory of Open Access Journals (Sweden)

    Delphine eVincent

    2016-01-01

    Full Text Available Milk is a complex fluid whose proteome displays a diverse set of proteins of high abundance such as caseins and medium to low abundance whey proteins such as ß-lactoglobulin, lactoferrin, immunoglobulins, glycoproteins, peptide hormones and enzymes. A sample preparation method that enables high reproducibility and throughput is key in reliably identifying proteins present or proteins responding to conditions such as a diet, health or genetics. Using skim milk samples from Jersey and Holstein-Friesian cows, we compared three extraction procedures which have not previously been applied to samples of cows’ milk. Method A (urea involved a simple dilution of the milk in a urea-based buffer, method B (TCA/acetone involved a trichloroacetic acid (TCA/acetone precipitation and method C (methanol/chloroform involved a tri-phasic partition method in chloroform/methanol solution. Protein assays, SDS-PAGE profiling, and trypsin digestion followed by nanoHPLC-electrospray ionisation-tandem mass spectrometry (nLC-ESI-MS/MS analyses were performed to assess their efficiency. Replicates were used at each analytical step (extraction, digestion, injection to assess reproducibility. Mass spectrometry (MS data are available via ProteomeXchange with identifier PXD002529. Overall 186 unique accessions, major and minor proteins, were identified with a combination of methods. Method C (methanol/chloroform yielded the best resolved SDS-patterns and highest protein recovery rates, method A (urea yielded the greatest number of accessions, and, of the three procedures, method B (TCA/acetone was the least compatible of all with a wide range of downstream analytical procedures. Our results also highlighted breed differences between the proteins in milk of Jersey and Holstein-Friesian cows.

  18. Research and Development from the bottom up

    DEFF Research Database (Denmark)

    Brem, Alexander; Wolfram, P.

    2014-01-01

    and ecological context or the growing interest of developed market firms in approaches from emerging markets. Hence, the presented framework supports further research in new paradigms for research and development (R&D) in developed market firms (DMFs), particularly in relation to emerging markets. This framework...... enables scholars to compare concepts from developed and emerging markets, to address studies specifically by using consistent terms, and to advance research into the concepts according their characterization....

  19. Report on the Bottom-Up Review

    Science.gov (United States)

    1993-10-01

    an up- North Dakota, would consist of a ground-based radar graded Patriot missile or a new "hit-to- kill " interceptor (GBR), 100 ground-based...civilian employ-drawdow byappoximtel 40,00 mor peple to tions already in place, replacing two civilian employ-draw down by approximately 400,000 more

  20. Neoliberalism Viewed From the Bottom Up

    DEFF Research Database (Denmark)

    Danneris, Sophie

    2017-01-01

    the viewpoint of the vulnerable benefit claimants who encounter it on a daily basis. The analysis is based on a qualitative longitudinal study conducted from 2013 to 2015, which shows how, in varying ways, clients routinely cope with being part of a neoliberal welfare state: by resignation, by taking action...

  1. Big Data from the bottom up

    Directory of Open Access Journals (Sweden)

    Nick Couldry

    2014-07-01

    Full Text Available This short article argues that an adequate response to the implications for governance raised by ‘Big Data’ requires much more attention to agency and reflexivity than theories of ‘algorithmic power’ have so far allowed. It develops this through two contrasting examples: the sociological study of social actors used of analytics to meet their own social ends (for example, by community organisations and the study of actors’ attempts to build an economy of information more open to civic intervention than the existing one (for example, in the environmental sphere. The article concludes with a consideration of the broader norms that might contextualise these empirical studies, and proposes that they can be understood in terms of the notion of voice, although the practical implementation of voice as a norm means that voice must sometimes be considered via the notion of transparency.

  2. Top down vision or bottom up demand?

    African Journals Online (AJOL)

    urbanisation, people have moved further apart or closer to each other, .... residents and other key stakeholders. .... life and places to live, work and play in ...... planet. London: Butler and Tanner Ltd. SCHOONRAAD, M.D. 2002. Cultural.

  3. Bottom-up Experiments and Concrete Utopias

    DEFF Research Database (Denmark)

    Andersson, Lasse

    2010-01-01

    Artiklen undersøger hvorledes brugerdrevne experimenter kan udfordre den standardiserede erhvervsorienterede udgave af Oplevelsesbyen og via eksperimentet stimulerer lokalt forankrede og demokratiske udgaver af en oplevelses- og vidensbaseret by....

  4. Anatomy guided bottom up creature skinning

    OpenAIRE

    Navarro Newball, Andrés Adolfo; Herrera Botero, Francisco Julián; Loaiza Buitrago, Diego Fernando

    2011-01-01

    Es posible generar la malla de la piel a partir de la anatomía interna. Este artículo presenta un método que recibe huesos, un conjunto de músculos y un conjunto de órganos complementarios para generar la piel. El método inicia en el fondo de la anatomía y genera una serie de puntos clave que luego proyecta en un plano espejo que corta la criatura por la mitad. Una vez en el plano, los puntos son triangulados y reflejados. Posteriormente, la malla de la piel es ajustad...

  5. Bottom Up Project Cost and Risk Modeling

    Data.gov (United States)

    National Aeronautics and Space Administration — Microcosm along with its partners HRP Systems, End-to-End Analytics, and ARES Corporation (unfunded in Phase I), propose to develop a new solution for detailed data...

  6. Policy intersections: Strengthening bottom up accountability amidst ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Sexual abuse and access to justice for rural women in West Africa. This research takes place within the context of several major overlapping factors in West Africa: View moreSexual abuse and access to justice for rural women in West Africa ...

  7. Ecological origins of object salience: reward, uncertainty, aversiveness and novelty

    Directory of Open Access Journals (Sweden)

    Ali Ghazizadeh

    2016-08-01

    Full Text Available Among many objects around us, some of them are more salient than others (i.e., attract our attention automatically. Some objects may be inherently salient (e.g., brighter, but others may become salient by virtue of their ecological relevance through experience. However, the importance of ecological experience in guiding attention has not been studied systematically. To address this question, we let subjects (macaque monkeys view a large number of complex objects (>300, each experienced repeatedly (>5 days with rewarding, aversive or no outcome association (mere-perceptual exposure. Test of salience was done on separate days using free viewing with no outcome. We found that gaze was biased among the objects from the outset, affecting saccades to objects or fixations within objects. When the outcome was rewarding, gaze preference was stronger (i.e. positive for objects with larger or equal but uncertain rewards. The effects of aversive outcomes were variable. Gaze preference was positive for some outcome associations (e.g. airpuff, but negative for others (e.g. time-out, possibly due to differences in threat levels. Finally, novel objects attracted gaze, but mere perceptual exposure of objects reduced their salience (learned negative salience. Our results show that, in primates, object salience is strongly influenced by previous ecological experience and is supported by a large memory capacity. Owing to such learned salience, the capacity to rapidly choose important objects can grow during the entire life to promote biological fitness.

  8. Visual saliency in MPEG-4 AVC video stream

    Science.gov (United States)

    Ammar, M.; Mitrea, M.; Hasnaoui, M.; Le Callet, P.

    2015-03-01

    Visual saliency maps already proved their efficiency in a large variety of image/video communication application fields, covering from selective compression and channel coding to watermarking. Such saliency maps are generally based on different visual characteristics (like color, intensity, orientation, motion,…) computed from the pixel representation of the visual content. This paper resumes and extends our previous work devoted to the definition of a saliency map solely extracted from the MPEG-4 AVC stream syntax elements. The MPEG-4 AVC saliency map thus defined is a fusion of static and dynamic map. The static saliency map is in its turn a combination of intensity, color and orientation features maps. Despite the particular way in which all these elementary maps are computed, the fusion techniques allowing their combination plays a critical role in the final result and makes the object of the proposed study. A total of 48 fusion formulas (6 for combining static features and, for each of them, 8 to combine static to dynamic features) are investigated. The performances of the obtained maps are evaluated on a public database organized at IRCCyN, by computing two objective metrics: the Kullback-Leibler divergence and the area under curve.

  9. Bottom-up and top-down fabrication of nanowire-based electronic devices: In situ doping of vapor liquid solid grown silicon nanowires and etch-dependent leakage current in InGaAs tunnel junctions

    Science.gov (United States)

    Kuo, Meng-Wei

    Semiconductor nanowires are important components in future nanoelectronic and optoelectronic device applications. These nanowires can be fabricated using either bottom-up or top-down methods. While bottom-up techniques can achieve higher aspect ratio at reduced dimension without having surface and sub-surface damage, uniform doping distributions with abrupt junction profiles are less challenging for top-down methods. In this dissertation, nanowires fabricated by both methods were systematically investigated to understand: (1) the in situ incorporation of boron (B) dopants in Si nanowires grown by the bottom-up vapor-liquid-solid (VLS) technique, and (2) the impact of plasma-induced etch damage on InGaAs p +-i-n+ nanowire junctions for tunnel field-effect transistors (TFETs) applications. In Chapter 2 and 3, the in situ incorporation of B in Si nanowires grown using silane (SiH4) or silicon tetrachloride (SiCl4) as the Si precursor and trimethylboron (TMB) as the p-type dopant source is investigated by I-V measurements of individual nanowires. The results from measurements using a global-back-gated test structure reveal nonuniform B doping profiles on nanowires grown from SiH4, which is due to simultaneous incorporation of B from nanowire surface and the catalyst during VLS growth. In contrast, a uniform B doping profile in both the axial and radial directions is achieved for TMBdoped Si nanowires grown using SiCl4 at high substrate temperatures. In Chapter 4, the I-V characteristics of wet- and dry-etched InGaAs p+-i-n+ junctions with different mesa geometries, orientations, and perimeter-to-area ratios are compared to evaluate the impact of the dry etch process on the junction leakage current properties. Different post-dry etch treatments, including wet etching and thermal annealing, are performed and the effectiveness of each is assessed by temperaturedependent I-V measurements. As compared to wet-etched control devices, dry-etched junctions have a significantly

  10. Hierarchical mask creation for intelligent image coding using saliency maps

    Directory of Open Access Journals (Sweden)

    Radoslav Vargic

    2016-12-01

    Full Text Available In this paper we analyze basic mask creation methods for intelligent image coding using saliency maps. For saliency maps based image coding we use specific extension of SPIHT algorithm called SM SPIHT related to region of interest encoding but extending this approach further, ending with individual weight of importance for each pixel in image using the form of saliency map. This approach is proved to be effective. In this article we analyze impact of different basic hierarchical mask creation methods, which have impact on error separation between salient and not salient parts of the image. The results indicate that proposed mask creation method outperforms JPEG2000 based mask tree creation method.

  11. The application of an optically switched dielectrophoretic (ODEP) force for the manipulation and assembly of cell-encapsulating alginate microbeads in a microfluidic perfusion cell culture system for bottom-up tissue engineering.

    Science.gov (United States)

    Lin, Yen-Heng; Yang, Ya-Wen; Chen, Yi-Dao; Wang, Shih-Siou; Chang, Yu-Han; Wu, Min-Hsien

    2012-03-21

    This study reports the utilisation of an optically switched dielectrophoretic (ODEP) force for the manipulation and assembly of cell-encapsulating alginate microbeads in a microfluidic perfusion cell culture system for bottom-up tissue engineering. One of the key features of this system is the ODEP force-based mechanism, which allows a commercial projector to be coupled with a computer to manipulate and assemble cell-encapsulating microbeads in an efficient, manageable, and user-friendly manner. Another distinctive feature is the design of the microfluidic cell culture chip, which allows the patterned cell-encapsulating microbeads to be cultivated on site under culture medium perfusion conditions. For demonstrating its application in bottom-up cartilage tissue engineering, chondrocyte-encapsulating alginate microbeads varying in encapsulated cell densities were generated. The manipulation forces associated with operating the alginate microbeads were experimentally evaluated. The results revealed that the measured manipulation forces increased with increases in both the applied electric voltage and the number of cells in the alginate microbeads. Nevertheless, the observed manipulation force was found to be independent of the size of the cell-free alginate microbeads. It can be speculated that the friction force may influence the estimation of the ODEP force within the experimental conditions investigated. In this study, chondrocyte-encapsulating alginate microbeads with three different cell densities were manipulated and assembled in the proposed microfluidic system to form a compact sheet-like cell culture construct that imitates the cell distribution in the cross-section of native articular cartilage. Moreover, the demonstration case also showed that the cell viability of the cultured cells in the microfluidic system remained as high as 96 ± 2%. In this study, four sheet-like cell culture constructs were stacked to create a larger assembled cell culture construct

  12. Design of the Bottom-up Innovation project--a participatory, primary preventive, organizational level intervention on work-related stress and well-being for workers in Dutch vocational education.

    Science.gov (United States)

    Schelvis, Roosmarijn M C; Oude Hengel, Karen M; Wiezer, Noortje M; Blatter, Birgitte M; van Genabeek, Joost A G M; Bohlmeijer, Ernst T; van der Beek, Allard J

    2013-08-15

    In the educational sector job demands have intensified, while job resources remained the same. A prolonged disbalance between demands and resources contributes to lowered vitality and heightened need for recovery, eventually resulting in burnout, sickness absence and retention problems. Until now stress management interventions in education focused mostly on strengthening the individual capacity to cope with stress, instead of altering the sources of stress at work at the organizational level. These interventions have been only partly effective in influencing burnout and well-being. Therefore, the "Bottom-up Innovation" project tests a two-phased participatory, primary preventive organizational level intervention (i.e. a participatory action approach) that targets and engages all workers in the primary process of schools. It is hypothesized that participating in the project results in increased occupational self-efficacy and organizational efficacy. The central research question: is an organization focused stress management intervention based on participatory action effective in reducing the need for recovery and enhancing vitality in school employees in comparison to business as usual? The study is designed as a controlled trial with mixed methods and three measurement moments: baseline (quantitative measures), six months and 18 months (quantitative and qualitative measures). At first follow-up short term effects of taking part in the needs assessment (phase 1) will be determined. At second follow-up the long term effects of taking part in the needs assessment will be determined as well as the effects of implemented tailored workplace solutions (phase 2). A process evaluation based on quantitative and qualitative data will shed light on whether, how and why the intervention (does not) work(s). "Bottom-up Innovation" is a combined effort of the educational sector, intervention providers and researchers. Results will provide insight into (1) the relation between

  13. Salience and conflict of work and family roles among employed men and women

    National Research Council Canada - National Science Library

    Irena Knežević; Ljiljana Gregov; Ana Šimunić

    2016-01-01

    The aim of this research was to determine the salience of work and family roles and to study the connection between role salience and the interference of different types of roles among working men and women...

  14. Fear of Success, Sex Role Attitudes, and Career Salience and Anxiety Levels of College Women.

    Science.gov (United States)

    Illfelder, Joyce K.

    1980-01-01

    Examines for female undergraduate students the relationship between fear of success, sex role attitudes, and career salience, and the relationship between fear of success, career salience, and trait anxiety. Results indicated that fear of success and sex-role attitudes, in combination, significantly predicted the level of career salience. (Author)

  15. Importance of Macrophyte Quality in Determining Life-History Traits of the Apple Snails Pomacea canaliculata: Implications for Bottom-Up Management of an Invasive Herbivorous Pest in Constructed Wetlands

    Science.gov (United States)

    Yam, Rita S. W.; Fan, Yen-Tzu; Wang, Tzu-Ting

    2016-01-01

    Pomacea canaliculata (Ampullariidae) has extensively invaded most Asian constructed wetlands and its massive herbivory of macrophytes has become a major cause of ecosystem dysfunctioning of these restored habitats. We conducted non-choice laboratory feeding experiments of P. canaliculata using five common macrophyte species in constructed wetlands including Ipomoea aquatica, Commelina communis, Nymphoides coreana, Acorus calamus and Phragmites australis. Effects of macrophytes on snail feeding, growth and fecundity responses were evaluated. Results indicated that P. canaliculata reared on Ipomoea had the highest feeding and growth rates with highest reproductive output, but all individuals fed with Phragmites showed lowest feeding rates and little growth with poorest reproductive output. Plant N and P contents were important for enhancing palatability, supporting growth and offspring quantity of P. canaliculata, whilst toughness, cellulose and phenolics had critically deterrent effects on various life-history traits. Although snail offspring quality was generally consistent regardless of maternal feeding conditions, the reduced growth and offspring quantity of the poorly-fed snails in constructed wetlands dominated by the less-palatable macrophytes could limit the invasive success of P. canaliculata. Effective bottom-up control of P. canaliculata in constructed wetlands should involve selective planting strategy using macrophytes with low nutrient and high toughness, cellulose and phenolic contents. PMID:26927135

  16. FTMS structure elucidation of natural products: application to muraymycin antibiotics using ESI multi-CHEF SORI-CID FTMS(n), the top-down/bottom-up approach, and HPLC ESI capillary-skimmer CID FTMS.

    Science.gov (United States)

    McDonald, Leonard A; Barbieri, Laurel R; Carter, Guy T; Kruppa, Gary; Feng, Xidong; Lotvin, Jason A; Siegel, Marshall M

    2003-06-01

    The molecular formulas for the structures and substructures of muraymycin antibiotics A1 (C52H90N14O19, MW 1214) and B1 (C49H83N11O18, MW 1113) were determined using electrospray ionization (ESI) Fourier transform mass spectrometry (FTMS). The muraymycin A1 and B1 structures were elucidated by utilizing capillary-skimmer fragmentation with up to five stages of mass spectrometry (MS5). Multi-CHEF, a multiple ion isolation method, was used at each stage of MS(n) to isolate a parent ion and up to four reference ions, for exact-mass calibration. The parent ions were fragmented by SORI-CID and the product ions internally calibrated with average absolute mass errors less than 1 ppm at each stage in the fragmentation processes. Using the top-down/bottom-up approach, the molecular formulas for the antibiotics were determined by summing the elemental formulas of the neutral losses, obtained by measuring the mass differences (skimmer CID FTMS by correlating their fragmentation patterns with those of muraymycins A1 and B1. Sequential neutral losses of an aminosugar, a valine, a uridine, and an ester fatty acid from the muraymycin parent ions provided diagnostic fragments for characterization.

  17. Convergência brasileira aos padrões internacionais de contabilidade pública vis-à-vis as estratégias top-down e bottom-up

    Directory of Open Access Journals (Sweden)

    Janyluce Rezende Gama

    2014-02-01

    Full Text Available O Brasil está em processo de convergência de sua contabilidade pública em relação aos padrões internacionais desenvolvidos pela Federação Internacional dos Contadores (Ifac. A implementação de sistemas de informação contábil é geralmente realizada por meio das abordagens top-down ou bottom-up. Assim, este estudo tem por objetivos: 1 identificar a abordagem adotada pelo governo federal brasileiro; 2 descrever o modelo de implementação do sistema de informação contábil público no Brasil; e 3 mapear o fluxo de informações e atores envolvidos no processo de convergência. A abordagem qualitativa foi adotada utilizando a pesquisa documental e análise de conteúdo de documentos disponíveis para operacionalizar a pesquisa. Foi identificado que o Brasil utiliza a abordagem middle-up-down, que favorece a interação entre múltiplos atores no processo, diferentemente da abordagem top-down, que segue o modelo internacional divulgado.

  18. Importance of Macrophyte Quality in Determining Life-History Traits of the Apple Snails Pomacea canaliculata: Implications for Bottom-Up Management of an Invasive Herbivorous Pest in Constructed Wetlands.

    Science.gov (United States)

    Yam, Rita S W; Fan, Yen-Tzu; Wang, Tzu-Ting

    2016-02-24

    Pomacea canaliculata (Ampullariidae) has extensively invaded most Asian constructed wetlands and its massive herbivory of macrophytes has become a major cause of ecosystem dysfunctioning of these restored habitats. We conducted non-choice laboratory feeding experiments of P. canaliculata using five common macrophyte species in constructed wetlands including Ipomoea aquatica, Commelina communis, Nymphoides coreana, Acorus calamus and Phragmites australis. Effects of macrophytes on snail feeding, growth and fecundity responses were evaluated. Results indicated that P. canaliculata reared on Ipomoea had the highest feeding and growth rates with highest reproductive output, but all individuals fed with Phragmites showed lowest feeding rates and little growth with poorest reproductive output. Plant N and P contents were important for enhancing palatability, supporting growth and offspring quantity of P. canaliculata, whilst toughness, cellulose and phenolics had critically deterrent effects on various life-history traits. Although snail offspring quality was generally consistent regardless of maternal feeding conditions, the reduced growth and offspring quantity of the poorly-fed snails in constructed wetlands dominated by the less-palatable macrophytes could limit the invasive success of P. canaliculata. Effective bottom-up control of P. canaliculata in constructed wetlands should involve selective planting strategy using macrophytes with low nutrient and high toughness, cellulose and phenolic contents.

  19. Importance of Macrophyte Quality in Determining Life-History Traits of the Apple Snails Pomacea canaliculata: Implications for Bottom-Up Management of an Invasive Herbivorous Pest in Constructed Wetlands

    Directory of Open Access Journals (Sweden)

    Rita S. W. Yam

    2016-02-01

    Full Text Available Pomacea canaliculata (Ampullariidae has extensively invaded most Asian constructed wetlands and its massive herbivory of macrophytes has become a major cause of ecosystem dysfunctioning of these restored habitats. We conducted non-choice laboratory feeding experiments of P. canaliculata using five common macrophyte species in constructed wetlands including Ipomoea aquatica, Commelina communis, Nymphoides coreana, Acorus calamus and Phragmites australis. Effects of macrophytes on snail feeding, growth and fecundity responses were evaluated. Results indicated that P. canaliculata reared on Ipomoea had the highest feeding and growth rates with highest reproductive output, but all individuals fed with Phragmites showed lowest feeding rates and little growth with poorest reproductive output. Plant N and P contents were important for enhancing palatability, supporting growth and offspring quantity of P. canaliculata, whilst toughness, cellulose and phenolics had critically deterrent effects on various life-history traits. Although snail offspring quality was generally consistent regardless of maternal feeding conditions, the reduced growth and offspring quantity of the poorly-fed snails in constructed wetlands dominated by the less-palatable macrophytes could limit the invasive success of P. canaliculata. Effective bottom-up control of P. canaliculata in constructed wetlands should involve selective planting strategy using macrophytes with low nutrient and high toughness, cellulose and phenolic contents.

  20. STEM enrichment programs and graduate school matriculation: the role of science identity salience

    Science.gov (United States)

    Serpe, Richard T.

    2013-01-01

    Improving the state of science education in the United States has become a national priority. One response to this problem has been the implementation of STEM enrichment programs designed to increase the number of students that enter graduate programs in science. Current research indicates enrichment programs have positive effects for student performance, degree completion, interest in science and graduate enrollment. Moreover, research suggests that beyond improving performance in STEM, and providing access to research experience and faculty mentoring, enrichment programs may also increase the degree to which students identify as scientists. However, researchers investigating the role of science identity on student outcomes have focused primarily on subjective outcomes, leaving a critical question of whether science identity also influences objective outcomes such as whether students attend graduate school. Using identity theory, this study addresses this issue by investigating science identity as a mechanism linking enrichment program participation to matriculation into graduate science programs. Quantitative results from a panel study of 694 students indicate that science identity salience, along with research experience and college GPA, mediate the effect of enrichment program participation on graduate school matriculation. Further, results indicate that although the social psychological process by which science identity salience develops operates independently from student GPA, science identity amplifies the effect of achievement on graduate school matriculation. These results indicate that policies seeking to increase the efficacy of enrichment programs and increase representation in STEM graduate programs should be sensitive to the social and academic aspects of STEM education. PMID:24578606