WorldWideScience

Sample records for brain ambiguous representations

  1. Ambiguous science and the visual representation of the real

    Science.gov (United States)

    Newbold, Curtis Robert

    The emergence of visual media as prominent and even expected forms of communication in nearly all disciplines, including those scientific, has raised new questions about how the art and science of communication epistemologically affect the interpretation of scientific phenomena. In this dissertation I explore how the influence of aesthetics in visual representations of science inevitably creates ambiguous meanings. As a means to improve visual literacy in the sciences, I call awareness to the ubiquity of visual ambiguity and its importance and relevance in scientific discourse. To do this, I conduct a literature review that spans interdisciplinary research in communication, science, art, and rhetoric. Furthermore, I create a paradoxically ambiguous taxonomy, which functions to exploit the nuances of visual ambiguities and their role in scientific communication. I then extrapolate the taxonomy of visual ambiguity and from it develop an ambiguous, rhetorical heuristic, the Tetradic Model of Visual Ambiguity. The Tetradic Model is applied to a case example of a scientific image as a demonstration of how scientific communicators may increase their awareness of the epistemological effects of ambiguity in the visual representations of science. I conclude by demonstrating how scientific communicators may make productive use of visual ambiguity, even in communications of objective science, and I argue how doing so strengthens scientific communicators' visual literacy skills and their ability to communicate more ethically and effectively.

  2. Representation and productive ambiguity in mathematics and the sciences

    CERN Document Server

    Grosholz, Emily R

    2007-01-01

    Emily Grosholz offers an original investigation of demonstration in mathematics and science, examining how it works and why it is persuasive. Focusing on geometrical demonstration, she shows the roles that representation and ambiguity play in mathematical discovery. She presents a wide range of case studies in mechanics, topology, algebra, logic, and chemistry, from ancient Greece to the present day, but focusing particularly on the seventeenth and twentieth centuries. Anyone interested in how mathematics works will find this a stimulating read.

  3. Ambiguity

    DEFF Research Database (Denmark)

    Stein, Mari-Klara; Jensen, Tina Blegind

    Digitalization is changing the nature of work in knowledge professions in significant ways. One of the oft-observed, yet poorly understood, consequences of work digitalization in this context is increased ambiguity, frequently captured under the notion of blurred boundaries and paradoxes. While...... the introduction of ICTs is often credited with the potential to bring about ambiguity in a work context, we lack an in-depth understanding of how and why digitalization can introduce ambiguity, and what ambiguity actually means in this context. In this paper, we aim to further our current theorization...... of ambiguity in ICT-enabled work in knowledge professions. We offer a conceptual clarification of three related issues: (1) why does digitalization introduce ambiguity, (2) what kinds of ambiguities digitalization introduces, and (3) how workers act upon ambiguity....

  4. Effects of task-switching on neural representations of ambiguous sound input.

    Science.gov (United States)

    Sussman, Elyse S; Bregman, Albert S; Lee, Wei-Wei

    2014-11-01

    The ability to perceive discrete sound streams in the presence of competing sound sources relies on multiple mechanisms that organize the mixture of the auditory input entering the ears. Many studies have focused on mechanisms that contribute to integrating sounds that belong together into one perceptual stream (integration) and segregating those that come from different sound sources (segregation). However, little is known about mechanisms that allow us to perceive individual sound sources within a dynamically changing auditory scene, when the input may be ambiguous, and heard as either integrated or segregated. This study tested the question of whether focusing on one of two possible sound organizations suppressed representation of the alternative organization. We presented listeners with ambiguous input and cued them to switch between tasks that used either the integrated or the segregated percept. Electrophysiological measures indicated which organization was currently maintained in memory. If mutual exclusivity at the neural level was the rule, attention to one of two possible organizations would preclude neural representation of the other. However, significant MMNs were elicited to both the target organization and the unattended, alternative organization, along with the target-related P3b component elicited only to the designated target organization. Results thus indicate that both organizations (integrated and segregated) were simultaneously maintained in memory regardless of which task was performed. Focusing attention to one aspect of the sounds did not abolish the alternative, unattended organization when the stimulus input was ambiguous. In noisy environments, such as walking on a city street, rapid and flexible adaptive processes are needed to help facilitate rapid switching to different sound sources in the environment. Having multiple representations available to the attentive system would allow for such flexibility, needed in everyday situations to

  5. Visual word representation in the brain

    NARCIS (Netherlands)

    Ramakrishnan, K.; Groen, I.; Scholte, S.; Smeulders, A.; Ghebreab, S.

    2013-01-01

    The human visual system is thought to use features of intermediate complexity for scene representation. How the brain computationally represents intermediate features is unclear, however. To study this, we tested the Bag of Words (BoW) model in computer vision against human brain activity. This

  6. A Nakanishi-based model illustrating the covariant extension of the pion GPD overlap representation and its ambiguities

    Science.gov (United States)

    Chouika, N.; Mezrag, C.; Moutarde, H.; Rodríguez-Quintero, J.

    2018-05-01

    A systematic approach for the model building of Generalized Parton Distributions (GPDs), based on their overlap representation within the DGLAP kinematic region and a further covariant extension to the ERBL one, is applied to the valence-quark pion's case, using light-front wave functions inspired by the Nakanishi representation of the pion Bethe-Salpeter amplitudes (BSA). This simple but fruitful pion GPD model illustrates the general model building technique and, in addition, allows for the ambiguities related to the covariant extension, grounded on the Double Distribution (DD) representation, to be constrained by requiring a soft-pion theorem to be properly observed.

  7. Do you like Arcimboldo's? Esthetic appreciation modulates brain activity in solving perceptual ambiguity.

    Science.gov (United States)

    Boccia, M; Nemmi, F; Tizzani, E; Guariglia, C; Ferlazzo, F; Galati, G; Giannini, A M

    2015-02-01

    Esthetic experience is a unique, affectively colored, self-transcending subject-object relationship in which cognitive processing is felt to flow differently than during everyday experiences. Notwithstanding previous multidisciplinary investigations, how esthetic experience modulates perception is still obscure. We used Arcimboldo's ambiguous portraits to assess how the esthetic context organizes ambiguous percepts. The study was carried out using functional magnetic resonance imaging (fMRI) in healthy young volunteers (mean age 25.45; S.D. 4.51; 9 females), during both an explicit esthetic judgment task and an artwork/non-artwork classification task. We show that a distinct neural mechanism in the fusiform gyrus contributes to the esthetic experience of ambiguous portraits, according to the valence of the esthetic experience. Ambiguous artworks eliciting a negative esthetic experience lead to more pronounced activation of the fusiform face areas than ambiguous artworks eliciting a positive esthetic experience. We also found an interaction between task and ambiguity in the right superior parietal lobule. Taken together, our results demonstrate that a neural mechanism in the content-dependent brain regions of face processing underlies the esthetic experience of ambiguous portraits. Furthermore, they suggest that esthetic experience interacts with perceptual qualities of stimuli in the right superior parietal lobe, supporting the idea that esthetic experience arises from the interaction between top-down orienting of attention and bottom-up perceptual facilitation. Copyright © 2014 Elsevier B.V. All rights reserved.

  8. Optimal spatiotemporal representation of multichannel EEG for recognition of brain states associated with distinct visual stimulus

    Science.gov (United States)

    Hramov, Alexander; Musatov, Vyacheslav Yu.; Runnova, Anastasija E.; Efremova, Tatiana Yu.; Koronovskii, Alexey A.; Pisarchik, Alexander N.

    2018-04-01

    In the paper we propose an approach based on artificial neural networks for recognition of different human brain states associated with distinct visual stimulus. Based on the developed numerical technique and the analysis of obtained experimental multichannel EEG data, we optimize the spatiotemporal representation of multichannel EEG to provide close to 97% accuracy in recognition of the EEG brain states during visual perception. Different interpretations of an ambiguous image produce different oscillatory patterns in the human EEG with similar features for every interpretation. Since these features are inherent to all subjects, a single artificial network can classify with high quality the associated brain states of other subjects.

  9. Theoretical background and experimental measurements of human brain noise intensity in perception of ambiguous images

    International Nuclear Information System (INIS)

    Runnova, Anastasiya E.; Hramov, Alexander E.; Grubov, Vadim V.; Koronovskii, Alexey A.; Kurovskaya, Maria K.; Pisarchik, Alexander N.

    2016-01-01

    We propose a theoretical approach associated with an experimental technique to quantitatively characterize cognitive brain activity in the perception of ambiguous images. Based on the developed theoretical background and the obtained experimental data, we introduce the concept of effective noise intensity characterizing cognitive brain activity and propose the experimental technique for its measurement. The developed theory, using the methods of statistical physics, provides a solid experimentally approved basis for further understanding of brain functionality. The rather simple way to measure the proposed quantitative characteristic of the brain activity related to the interpretation of ambiguous images will hopefully become a powerful tool for physicists, physiologists and medics. Our theoretical and experimental findings are in excellent agreement with each other.

  10. The known unknowns: neural representation of second-order uncertainty, and ambiguity

    Science.gov (United States)

    Bach, Dominik R.; Hulme, Oliver; Penny, William D.; Dolan, Raymond J.

    2011-01-01

    Predictions provided by action-outcome probabilities entail a degree of (first-order) uncertainty. However, these probabilities themselves can be imprecise and embody second-order uncertainty. Tracking second-order uncertainty is important for optimal decision making and reinforcement learning. Previous functional magnetic resonance imaging investigations of second-order uncertainty in humans have drawn on an economic concept of ambiguity, where action-outcome associations in a gamble are either known (unambiguous) or completely unknown (ambiguous). Here, we relaxed the constraints associated with a purely categorical concept of ambiguity and varied the second-order uncertainty of gambles continuously, quantified as entropy over second-order probabilities. We show that second-order uncertainty influences decisions in a pessimistic way by biasing second-order probabilities, and that second-order uncertainty is negatively correlated with posterior cingulate cortex activity. The category of ambiguous (compared to non-ambiguous) gambles also biased choice in a similar direction, but was associated with distinct activation of a posterior parietal cortical area; an activation that we show reflects a different computational mechanism. Our findings indicate that behavioural and neural responses to second-order uncertainty are distinct from those associated with ambiguity and may call for a reappraisal of previous data. PMID:21451019

  11. Processing and Representation of Ambiguous Words in Chinese Reading: Evidence from Eye Movements.

    Science.gov (United States)

    Shen, Wei; Li, Xingshan

    2016-01-01

    In the current study, we used eye tracking to investigate whether senses of polysemous words and meanings of homonymous words are represented and processed similarly or differently in Chinese reading. Readers read sentences containing target words which was either homonymous words or polysemous words. The contexts of text preceding the target words were manipulated to bias the participants toward reading the ambiguous words according to their dominant, subordinate, or neutral meanings. Similarly, disambiguating regions following the target words were also manipulated to favor either the dominant or subordinate meanings of ambiguous words. The results showed that there were similar eye movement patterns when Chinese participants read sentences containing homonymous and polysemous words. The study also found that participants took longer to read the target word and the disambiguating text following it when the prior context and disambiguating regions favored divergent meanings rather than the same meaning. These results suggested that homonymy and polysemy are represented similarly in the mental lexicon when a particular meaning (sense) is fully specified by disambiguating information. Furthermore, multiple meanings (senses) are represented as separate entries in the mental lexicon.

  12. Ambiguities in the Association Between Symmetries and Conservation Laws in the Presence of Alternative Lagrangian Representations

    International Nuclear Information System (INIS)

    Amitava Choudhuri; Subrata Ghosh; Talukdar, B.

    2011-01-01

    We identify two alternative Lagrangian representations for the damped harmonic oscillator characterised by a frictional coefficient γ. The first one is explicitly time independent while the second one involves time parameter explicitly. With separate attention to both Lagrangians we make use of the Noether theorem to compute the variational symmetries and conservation laws in order to study how association between them changes as one goes from one representation to the other. In the case of time independent representation squeezing symmetry leads to conservation of angular momentum for γ = 0, while for the time-dependent Lagrangian the same conserved quantity results from rotational invariance. The Lie algebra (g) of the symmetry vectors that leaves the action corresponding to the time-independent Lagrangian invariant is semi-simple. On the other hand, g is only a simple Lie algebra for the action characterised by the time-dependent Lagrangian. (authors)

  13. Intermittent behavior in the brain neuronal network in the perception of ambiguous images

    Science.gov (United States)

    Hramov, Alexander E.; Kurovskaya, Maria K.; Runnova, Anastasiya E.; Zhuravlev, Maxim O.; Grubov, Vadim V.; Koronovskii, Alexey A.; Pavlov, Alexey N.; Pisarchik, Alexander N.

    2017-03-01

    Characteristics of intermittency during the perception of ambiguous images have been studied in the case the Necker cube image has been used as a bistable object for demonstration in the experiments, with EEG being simultaneously measured. Distributions of time interval lengths corresponding to the left-oriented and right-oriented Necker cube perception have been obtain. EEG data have been analyzed using continuous wavelet transform which was shown that the destruction of alpha rhythm with accompanying generation of high frequency oscillations can serve as a electroencephalographical marker of Necker cube recognition process in human brain.

  14. Perceptual Representation as a Mechanism of Lexical Ambiguity Resolution: An Investigation of Span and Processing Time

    Science.gov (United States)

    Madden, Carol J.; Zwaan, Rolf A.

    2006-01-01

    In 2 experiments, the authors investigated the ability of high- and low-span comprehenders to construe subtle shades of meaning through perceptual representation. High- and low-span comprehenders responded to pictures that either matched or mismatched a target object's shape as implied by the preceding sentence context. At 750 ms after hearing the…

  15. Interacting Brain Modules for Memory: An Adaptive Representations Architecture

    National Research Council Canada - National Science Library

    Gluck, Mark A

    2008-01-01

    ...) as a central system for creating optimal and adaptive stimulus representations, and then worked outwards from the hippocampal region to the brain systems that it modulates, including the cerebellum...

  16. The subcortical role of language processing. High level linguistic features such as ambiguity-resolution and the human brain; an fMRI study.

    Science.gov (United States)

    Ketteler, Daniel; Kastrau, Frank; Vohn, Rene; Huber, Walter

    2008-02-15

    In the present study, we were interested in the neurofunctional representations of ambiguity processing by using functional magnetic resonance imaging (fMRI). Twelve right-handed, healthy adults aged between 21 and 29 years (6 male, 6 female) underwent an ambiguity resolution task with 4 different conditions (dominant vs. non-dominant; dominant vs. distractor; non-dominant vs. distractor; distractor vs. distractor). After subtraction of the corresponding control task (distractor vs. distractor) we found significant activation especially in the thalamus and some parts of the basal ganglia (caudate nucleus, putamen). Our findings implicate a participation of the thalamus and other basal ganglia circuits in high level linguistic functions and match with theoretical considerations on this highly controversial topic. Subcortical neural circuits probably become activated when the language processing system cannot rely entirely on automatic mechanisms but has to recruit controlled processes as well. Furthermore, we found broad activation in the inferior parietal lobule, the prefrontal gyrus, pre-SMA and SMA and the cingulate cortex. This might reflect a strategic semantic search mechanism which probably can be illustrated with connectionist models of language processing. According to this, we hypothesize a neuroregulatory role for the thalamus and basal ganglia in regulating and monitoring the release of preformulated language segments for motor programming and semantic verification. According to our findings there is strong evidence, that especially the thalamus, the caudate nucleus, the cingulate cortex, the inferior parietal lobule and the prefrontal cortex are responsible for an accurate ambiguity resolution in the human brain.

  17. Ambiguity attitudes

    NARCIS (Netherlands)

    Trautmann, Stefan; van de Kuilen, Gijs; Keren, Gideon; Wu, George

    2015-01-01

    This chapter reviews the experimental literature on ambiguity attitudes, focusing on three topics. First, it considers various approaches to operationalize ambiguity in experiments. Second, the chapter reviews basic findings in the field regarding the prevalence of ambiguity aversion and ambiguity

  18. Ambiguous figures – What happens in the brain when perception changes but not the stimulus

    Directory of Open Access Journals (Sweden)

    Jürgen eKornmeier

    2012-03-01

    Full Text Available During observation of ambiguous figures our perception alternates spontaneously although the visual information stays unchanged. Research on this phenomenon so far suffered from the difficulty to determine the instant of the endogenous reversals with sufficient precision. A novel experimental paradigm with discontinuous stimulus presentation improved on previous temporal estimates of the reversal event by factor 3. It revealed that disambiguation of ambiguous visual information takes roughly 50 ms or two loops of recurrent neural activity. Further, the decision about the perceptual outcome has taken place at least 340 ms before the observer is able to indicate the consciously perceived reversal manually. We provide a short review about physiological studies on multistable perception with a focus on electrophysiological data and present a new perspective on multistable perception that can easily integrate previous apparently contradicting explanatory approaches. Finally we propose possible extensions towards other research fields where ambiguous figure perception may be useful as an investigative tool.

  19. Abstract representations of associated emotions in the human brain.

    Science.gov (United States)

    Kim, Junsuk; Schultz, Johannes; Rohe, Tim; Wallraven, Christian; Lee, Seong-Whan; Bülthoff, Heinrich H

    2015-04-08

    Emotions can be aroused by various kinds of stimulus modalities. Recent neuroimaging studies indicate that several brain regions represent emotions at an abstract level, i.e., independently from the sensory cues from which they are perceived (e.g., face, body, or voice stimuli). If emotions are indeed represented at such an abstract level, then these abstract representations should also be activated by the memory of an emotional event. We tested this hypothesis by asking human participants to learn associations between emotional stimuli (videos of faces or bodies) and non-emotional stimuli (fractals). After successful learning, fMRI signals were recorded during the presentations of emotional stimuli and emotion-associated fractals. We tested whether emotions could be decoded from fMRI signals evoked by the fractal stimuli using a classifier trained on the responses to the emotional stimuli (and vice versa). This was implemented as a whole-brain searchlight, multivoxel activation pattern analysis, which revealed successful emotion decoding in four brain regions: posterior cingulate cortex (PCC), precuneus, MPFC, and angular gyrus. The same analysis run only on responses to emotional stimuli revealed clusters in PCC, precuneus, and MPFC. Multidimensional scaling analysis of the activation patterns revealed clear clustering of responses by emotion across stimulus types. Our results suggest that PCC, precuneus, and MPFC contain representations of emotions that can be evoked by stimuli that carry emotional information themselves or by stimuli that evoke memories of emotional stimuli, while angular gyrus is more likely to take part in emotional memory retrieval. Copyright © 2015 the authors 0270-6474/15/355655-09$15.00/0.

  20. Representation of grammatical categories of words in the brain.

    Science.gov (United States)

    Hillis, A E; Caramazza, A

    1995-01-01

    We report the performance of a patient who, as a consequence of left frontal and temporoparietal strokes, makes far more errors on nouns than on verbs in spoken output tasks, but makes far more errors on verbs than on nouns in written input tasks. This double dissociation within a single patient with respect to grammatical category provides evidence for the hypothesis that phonological and orthographic representations of nouns and verbs are processed by independent neural mechanisms. Furthermore, the opposite dissociation in the verbal output modality, an advantage for nouns over verbs in spoken tasks, by a different patient using the same stimuli has also been reported (Caramazza & Hillis, 1991). This double dissociation across patients on the same task indicates that results cannot be ascribed to "greater difficulty" with one type of stimulus, and provides further evidence for the view that grammatical category information is an important organizational principle of lexical knowledge in the brain.

  1. Neural representation of expected value in the adolescent brain.

    Science.gov (United States)

    Barkley-Levenson, Emily; Galván, Adriana

    2014-01-28

    Previous work shows that the adolescent reward system is hyperactive, but this finding may be confounded by differences in how teens value money. To address this, we examined the neural ontogeny of objective value representation. Adolescent and adult participants performed a monetary gambling task in which they chose to accept or reject gambles of varying expected value. Increasing expected value had a stronger influence over gambling choices in adolescents relative to adults, an effect that was paralleled by greater activation in the ventral striatum in adolescents. This unique adolescent ventral striatum response remained even after matching groups on acceptance behavior. These behavioral and neural data suggest that the value of available options has a greater influence in adolescent versus adult choices, even when objective value and subjective choice are held constant. This research provides further evidence that hyperactivation of reward circuitry in adolescence may be a normative ontogenetic shift that is due to greater valuation in the adolescent brain.

  2. Brain correlates of mathematical competence in processing mathematical representations

    Directory of Open Access Journals (Sweden)

    Roland H. Grabner

    2011-11-01

    Full Text Available The ability to extract numerical information from different representation formats (e.g., equations, tables, or diagrams is a key component of mathematical competence but little is known about its neural correlate. Previous studies comparing mathematically less and more competent adults have focused on mental arithmetic and reported differences in left angular gyrus activity which were interpreted to reflect differential reliance on arithmetic fact retrieval during problem solving. The aim of the present functional magnetic resonance imaging (fMRI study was to investigate the brain correlates of mathematical competence in a task requiring the processing of typical mathematical representations. Twenty-eight adults of lower and higher mathematical competence worked on a representation matching task in which they had to evaluate whether the numerical information of a symbolic equation matches that of a bar chart. Two task conditions without and one condition with arithmetic demands were administered. Both competence groups performed equally well in the non-arithmetic conditions and only differed in accuracy in the condition requiring calculation. Activation contrasts between the groups revealed consistently stronger left angular gyrus activation in the more competent individuals across all three task conditions. The finding of competence-related activation differences independently of arithmetic demands suggests that more and less competent individuals differ in a cognitive process other than arithmetic fact retrieval. Specifically, it is argued that the stronger left angular gyrus activity in the more competent adults may reflect their higher proficiency in processing mathematical symbols. Moreover, the study demonstrates competence-related parietal activation differences that were not accompanied by differential experimental performance.

  3. Are ambiguity aversion and ambiguity intolerance identical? A neuroeconomics investigation.

    Science.gov (United States)

    Tanaka, Yusuke; Fujino, Junya; Ideno, Takashi; Okubo, Shigetaka; Takemura, Kazuhisa; Miyata, Jun; Kawada, Ryosaku; Fujimoto, Shinsuke; Kubota, Manabu; Sasamoto, Akihiko; Hirose, Kimito; Takeuchi, Hideaki; Fukuyama, Hidenao; Murai, Toshiya; Takahashi, Hidehiko

    2014-01-01

    In recent years, there has been growing interest in understanding a person's reaction to ambiguous situations, and two similar constructs related to ambiguity, "ambiguity aversion" and "ambiguity intolerance," are defined in different disciplines. In the field of economic decision-making research, "ambiguity aversion" represents a preference for known risks relative to unknown risks. On the other hand, in clinical psychology, "ambiguity intolerance" describes the tendency to perceive ambiguous situations as undesirable. However, it remains unclear whether these two notions derived from different disciplines are identical or not. To clarify this issue, we combined an economic task, psychological questionnaires, and voxel-based morphometry (VBM) of structural brain magnetic resonance imaging (MRI) in a sample of healthy volunteers. The individual ambiguity aversion tendency parameter, as measured by our economic task, was negatively correlated with agreeableness scores on the self-reported version of the Revised NEO Personality Inventory. However, it was not correlated with scores of discomfort with ambiguity, one of the subscales of the Need for Closure Scale. Furthermore, the ambiguity aversion tendency parameter was negatively correlated with gray matter (GM) volume of areas in the lateral prefrontal cortex and parietal cortex, whereas ambiguity intolerance was not correlated with GM volume in any region. Our results suggest that ambiguity aversion, described in decision theory, may not necessarily be identical to ambiguity intolerance, referred to in clinical psychology. Cautious applications of decision theory to clinical neuropsychiatry are recommended.

  4. Decision ambiguity is mediated by a late positive potential originating from cingulate cortex.

    Science.gov (United States)

    Sun, Sai; Zhen, Shanshan; Fu, Zhongzheng; Wu, Daw-An; Shimojo, Shinsuke; Adolphs, Ralph; Yu, Rongjun; Wang, Shuo

    2017-08-15

    People often make decisions in the face of ambiguous information, but it remains unclear how ambiguity is represented in the brain. We used three types of ambiguous stimuli and combined EEG and fMRI to examine the neural representation of perceptual decisions under ambiguity. We identified a late positive potential, the LPP, which differentiated levels of ambiguity, and which was specifically associated with behavioral judgments about choices that were ambiguous, rather than passive perception of ambiguous stimuli. Mediation analyses together with two further control experiments confirmed that the LPP was generated only when decisions are made (not during mere perception of ambiguous stimuli), and only when those decisions involved choices on a dimension that is ambiguous. A further control experiment showed that a stronger LPP arose in the presence of ambiguous stimuli compared to when only unambiguous stimuli were present. Source modeling suggested that the LPP originated from multiple loci in cingulate cortex, a finding we further confirmed using fMRI and fMRI-guided ERP source prediction. Taken together, our findings argue for a role of an LPP originating from cingulate cortex in encoding decisions based on task-relevant perceptual ambiguity, a process that may in turn influence confidence judgment, response conflict, and error correction. Copyright © 2017 Elsevier Inc. All rights reserved.

  5. Ambiguous chair

    DEFF Research Database (Denmark)

    Manelius, Anne-Mette

    2011-01-01

    Bidrag til gør-det-selv bog, hvor det beskrives i udførlige tegninger, hvordan man bygger sin egen 'Ambiguous Chair', en tekstilforskallet stol.......Bidrag til gør-det-selv bog, hvor det beskrives i udførlige tegninger, hvordan man bygger sin egen 'Ambiguous Chair', en tekstilforskallet stol....

  6. OPTIMAL REPRESENTATION OF MER SIGNALS APPLIED TO THE IDENTIFICATION OF BRAIN STRUCTURES DURING DEEP BRAIN STIMULATION

    Directory of Open Access Journals (Sweden)

    Hernán Darío Vargas Cardona

    2015-07-01

    Full Text Available Identification of brain signals from microelectrode recordings (MER is a key procedure during deep brain stimulation (DBS applied in Parkinson’s disease patients. The main purpose of this research work is to identify with high accuracy a brain structure called subthalamic nucleus (STN, since it is the target structure where the DBS achieves the best therapeutic results. To do this, we present an approach for optimal representation of MER signals through method of frames. We obtain coefficients that minimize the Euclidean norm of order two. From optimal coefficients, we extract some features from signals combining the wavelet packet and cosine dictionaries. For a comparison frame with the state of the art, we also process the signals using the discrete wavelet transform (DWT with several mother functions. We validate the proposed methodology in a real data base. We employ simple supervised machine learning algorithms, as the K-Nearest Neighbors classifier (K-NN, a linear Bayesian classifier (LDC and a quadratic Bayesian classifier (QDC. Classification results obtained with the proposed method improves significantly the performance of the DWT. We achieve a positive identification of the STN superior to 97,6%. Identification outcomes achieved by the MOF are highly accurate, as we can potentially get a false positive rate of less than 2% during the DBS.

  7. Brain-to-text: Decoding spoken phrases from phone representations in the brain

    Directory of Open Access Journals (Sweden)

    Christian eHerff

    2015-06-01

    Full Text Available It has long been speculated whether communication between humans and machines based on natural speech related cortical activity is possible. Over the past decade, studies have suggested that it is feasible to recognize isolated aspects of speech from neural signals, such as auditory features, phones or one of a few isolated words. However, until now it remained an unsolved challenge to decode continuously spoken speech from the neural substrate associated with speech and language processing. Here, we show for the first time that continuously spoken speech can be decoded into the expressed words from intracranial electrocorticographic (ECoG recordings. Specifically, we implemented a system, which we call Brain-To-Text that models single phones, employs techniques from automatic speech recognition (ASR, and thereby transforms brain activity while speaking into the corresponding textual representation. Our results demonstrate that our system achieved word error rates as low as 25% and phone error rates below 50%. Additionally, our approach contributes to the current understanding of the neural basis of continuous speech production by identifying those cortical regions that hold substantial information about individual phones. In conclusion, the Brain-To-Text system described in this paper represents an important step towards human-machine communication based on imagined speech.

  8. Brain activity associated with translation from a visual to a symbolic representation in algebra and geometry.

    Science.gov (United States)

    Leikin, Mark; Waisman, Ilana; Shaul, Shelley; Leikin, Roza

    2014-03-01

    This paper presents a small part of a larger interdisciplinary study that investigates brain activity (using event related potential methodology) of male adolescents when solving mathematical problems of different types. The study design links mathematics education research with neurocognitive studies. In this paper we performed a comparative analysis of brain activity associated with the translation from visual to symbolic representations of mathematical objects in algebra and geometry. Algebraic tasks require translation from graphical to symbolic representation of a function, whereas tasks in geometry require translation from a drawing of a geometric figure to a symbolic representation of its property. The findings demonstrate that electrical activity associated with the performance of geometrical tasks is stronger than that associated with solving algebraic tasks. Additionally, we found different scalp topography of the brain activity associated with algebraic and geometric tasks. Based on these results, we argue that problem solving in algebra and geometry is associated with different patterns of brain activity.

  9. Interacting Brain Modules for Memory: An Adaptive Representations Architecture

    Science.gov (United States)

    2008-06-01

    and sensory preconditioning, which depend on compressing together the representations of conditioned stimulus and context and/or co-occurring cues...learning and rewarded behavior, partly because of clear evidence of their key role in drugs of addiction (DiChiara, 1999), and because they are among the...Approach of this sort is a Pavlovian response---it is like a pre-wired action inspired by novelty (and also reward prediction). Theoretical

  10. Oscillatory activity in the infant brain and the representation of small numbers

    Directory of Open Access Journals (Sweden)

    Sumie eLeung

    2016-02-01

    Full Text Available Gamma-band oscillatory activity (GBA is an established neural signature of sustained occluded object representation in infants and adults. However, it is not yet known whether the magnitude of GBA in the infant brain reflects the quantity of occluded items held in memory. To examine this, we compared GBA of 6- to 8-month-old infants during occlusion periods after the representation of two objects versus that of one object. We found that maintaining a representation of two objects during occlusion resulted in significantly greater GBA relative to maintaining a single object. Further, this enhancement was located in the right occipital region, which is consistent with previous object representation research in adults and infants. We conclude that enhanced GBA reflects neural processes underlying infants’ representation of small numbers.

  11. Oscillatory Activity in the Infant Brain and the Representation of Small Numbers.

    Science.gov (United States)

    Leung, Sumie; Mareschal, Denis; Rowsell, Renee; Simpson, David; Iaria, Leon; Grbic, Amanda; Kaufman, Jordy

    2016-01-01

    Gamma-band oscillatory activity (GBA) is an established neural signature of sustained occluded object representation in infants and adults. However, it is not yet known whether the magnitude of GBA in the infant brain reflects the quantity of occluded items held in memory. To examine this, we compared GBA of 6-8 month-old infants during occlusion periods after the representation of two objects vs. that of one object. We found that maintaining a representation of two objects during occlusion resulted in significantly greater GBA relative to maintaining a single object. Further, this enhancement was located in the right occipital region, which is consistent with previous object representation research in adults and infants. We conclude that enhanced GBA reflects neural processes underlying infants' representation of small numbers.

  12. Ambiguous Intimacy

    DEFF Research Database (Denmark)

    Houmøller, Kathrin

    2015-01-01

    relations and intimacy is riddled with inevitability and precarity. Here, it is argued, intimacy is ambiguous: allowed and resisted, longed for and feared - simultaneously encompassing practices of closeness and distance, connecting and disconnecting. To make a life in this particular place sometimes...

  13. Ambiguous Adaptation

    DEFF Research Database (Denmark)

    Møller Larsen, Marcus; Lyngsie, Jacob

    and reciprocal adaptation of informal governance structure create ambiguity in situations of contingencies, which, subsequently, increases the likelihood of premature relationship termination. Using a large sample of exchange relationships in the global service provider industry, we find support for a hypothesis...

  14. Ambiguous Adaptation

    DEFF Research Database (Denmark)

    Møller Larsen, Marcus; Lyngsie, Jacob

    2017-01-01

    We investigate the connection between contract duration, relational mechanisms, and premature relationship termination. Based on an analysis of a large sample of exchange relationships in the global service-provider industry, we argue that investments in either longer contract duration or more in...... ambiguous reference points for adaption and thus increase the likelihood of premature termination by restricting the parties' set of adaptive actions....

  15. Ambiguous Genitalia

    Science.gov (United States)

    ... that respond to testosterone. 5a-reductase deficiency. This enzyme defect impairs normal male hormone production. Ambiguous genitalia can also be a feature of certain rare, complex syndromes that affect many organ systems. Risk factors Family history may play a role in the development of ...

  16. The representation of grammatical categories in the brain.

    Science.gov (United States)

    Shapiro, Kevin; Caramazza, Alfonso

    2003-05-01

    Language relies on the rule-based combination of words with different grammatical properties, such as nouns and verbs. Yet most research on the problem of word retrieval has focused on the production of concrete nouns, leaving open a crucial question: how is knowledge about different grammatical categories represented in the brain, and what components of the language production system make use of it? Drawing on evidence from neuropsychology, electrophysiology and neuroimaging, we argue that information about a word's grammatical category might be represented independently of its meaning at the levels of word form and morphological computation.

  17. Representation

    National Research Council Canada - National Science Library

    Little, Daniel

    2006-01-01

    ...). The reason this is so is due to hierarchies that we take for granted. By hierarchies I mean that there is a layer of representation of us as individuals, as military professional, as members of a military unit and as citizens of an entire nation...

  18. Ambiguous walls

    DEFF Research Database (Denmark)

    Mody, Astrid

    2012-01-01

    The introduction of Light Emitting Diodes (LEDs) in the built environment has encouraged myriad applications, often embedded in surfaces as an integrated part of the architecture. Thus the wall as responsive luminous skin is becoming, if not common, at least familiar. Taking into account how walls...... have encouraged architectural thinking of enclosure, materiality, construction and inhabitation in architectural history, the paper’s aim is to define new directions for the integration of LEDs in walls, challenging the thinking of inhabitation and program. This paper introduces the notion...... of “ambiguous walls” as a more “critical” approach to design [1]. The concept of ambiguous walls refers to the diffuse status a lumious and possibly responsive wall will have. Instead of confining it can open up. Instead of having a static appearance, it becomes a context over time. Instead of being hard...

  19. Representation

    Science.gov (United States)

    2006-09-01

    two weeks to arrive. Source: http://beergame.mit.edu/ Permission Granted – MIT Supply Chain Forum 2005 Professor Sterman –Sloan School of...Management - MITSource: http://web.mit.edu/jsterman/www/ SDG /beergame.html Rules of Engagement The MIT Beer Game Simulation 04-04 Slide Number 10 Professor...Sterman –Sloan School of Management - MITSource: http://web.mit.edu/jsterman/www/ SDG /beergame.html What is the Significance of Representation

  20. Multivariate representation of food preferences in the human brain.

    Science.gov (United States)

    Pogoda, Luca; Holzer, Matthias; Mormann, Florian; Weber, Bernd

    2016-12-01

    One major goal in decision neuroscience is to investigate the neuronal mechanisms being responsible for the computation of product preferences. The aim of the present fMRI study was to investigate whether similar patterns of brain activity, reflecting category dependent and category independent preference signals, can be observed in case of different food product categories (i.e. chocolate bars and salty snacks). To that end we used a multivariate searchlight approach in which a linear support vector machine (l-SVM) was trained to distinguish preferred from non-preferred chocolate bars and subsequently tested its predictive power in case of chocolate bars (within category prediction) and salty snacks (across category prediction). Preferences were measured by a binary forced choice decision paradigm before the fMRI task. In the scanner, subjects saw only one product per trial which they had to rate after presentation. Consistent with previous multi voxel pattern analysis (MVPA) studies, we found category dependent preference signals in the ventral parts of medial prefrontal cortex (mPFC), but also in dorsal anterior cingulate cortex (dACC) and dorsolateral prefrontal cortex (dlPFC). Category independent preference signals were observed in the dorsal parts of mPFC, dACC, and dlPFC. While the first two results have also been reported in a closely related study, the activation in dlPFC is new in this context. We propose that the dlPFC activity does not reflect the products' value computation per se, but rather a modulatory signal which is computed in anticipation of the forthcoming product rating after stimulus presentation. Furthermore we postulate that this kind of dlPFC activation emerges only if the anticipated choices fall into the domain of primary rewards, such as foods. Thus, in contrast to previous studies which investigated preference decoding for stimuli from utterly different categories, the present study revealed some food domain specific aspects of

  1. Morphing between expressions dissociates continuous from categorical representations of facial expression in the human brain

    Science.gov (United States)

    Harris, Richard J.; Young, Andrew W.; Andrews, Timothy J.

    2012-01-01

    Whether the brain represents facial expressions as perceptual continua or as emotion categories remains controversial. Here, we measured the neural response to morphed images to directly address how facial expressions of emotion are represented in the brain. We found that face-selective regions in the posterior superior temporal sulcus and the amygdala responded selectively to changes in facial expression, independent of changes in identity. We then asked whether the responses in these regions reflected categorical or continuous neural representations of facial expression. Participants viewed images from continua generated by morphing between faces posing different expressions such that the expression could be the same, could involve a physical change but convey the same emotion, or could differ by the same physical amount but be perceived as two different emotions. We found that the posterior superior temporal sulcus was equally sensitive to all changes in facial expression, consistent with a continuous representation. In contrast, the amygdala was only sensitive to changes in expression that altered the perceived emotion, demonstrating a more categorical representation. These results offer a resolution to the controversy about how facial expression is processed in the brain by showing that both continuous and categorical representations underlie our ability to extract this important social cue. PMID:23213218

  2. Decoding the dynamic representation of musical pitch from human brain activity.

    Science.gov (United States)

    Sankaran, N; Thompson, W F; Carlile, S; Carlson, T A

    2018-01-16

    In music, the perception of pitch is governed largely by its tonal function given the preceding harmonic structure of the music. While behavioral research has advanced our understanding of the perceptual representation of musical pitch, relatively little is known about its representational structure in the brain. Using Magnetoencephalography (MEG), we recorded evoked neural responses to different tones presented within a tonal context. Multivariate Pattern Analysis (MVPA) was applied to "decode" the stimulus that listeners heard based on the underlying neural activity. We then characterized the structure of the brain's representation using decoding accuracy as a proxy for representational distance, and compared this structure to several well established perceptual and acoustic models. The observed neural representation was best accounted for by a model based on the Standard Tonal Hierarchy, whereby differences in the neural encoding of musical pitches correspond to their differences in perceived stability. By confirming that perceptual differences honor those in the underlying neuronal population coding, our results provide a crucial link in understanding the cognitive foundations of musical pitch across psychological and neural domains.

  3. Dynamics of scene representations in the human brain revealed by magnetoencephalography and deep neural networks

    Science.gov (United States)

    Cichy, Radoslaw Martin; Khosla, Aditya; Pantazis, Dimitrios; Oliva, Aude

    2017-01-01

    Human scene recognition is a rapid multistep process evolving over time from single scene image to spatial layout processing. We used multivariate pattern analyses on magnetoencephalography (MEG) data to unravel the time course of this cortical process. Following an early signal for lower-level visual analysis of single scenes at ~100 ms, we found a marker of real-world scene size, i.e. spatial layout processing, at ~250 ms indexing neural representations robust to changes in unrelated scene properties and viewing conditions. For a quantitative model of how scene size representations may arise in the brain, we compared MEG data to a deep neural network model trained on scene classification. Representations of scene size emerged intrinsically in the model, and resolved emerging neural scene size representation. Together our data provide a first description of an electrophysiological signal for layout processing in humans, and suggest that deep neural networks are a promising framework to investigate how spatial layout representations emerge in the human brain. PMID:27039703

  4. Conceptual representations in mind and brain: theoretical developments, current evidence and future directions.

    Science.gov (United States)

    Kiefer, Markus; Pulvermüller, Friedemann

    2012-07-01

    Conceptual representations in long-term memory crucially contribute to perception and action, language and thought. However, the precise nature of these conceptual memory traces is discussed controversially. In particular, the grounding of concepts in the sensory and motor brain systems is the focus of a current debate. Here, we review theoretical accounts of the structure and neural basis of conceptual memory and evaluate them in light of recent empirical evidence. Models of conceptual processing can be distinguished along four dimensions: (i) amodal versus modality-specific, (ii) localist versus distributed, (iii) innate versus experience-dependent, and (iv) stable versus flexible. A systematic review of behavioral and neuroimaging studies in healthy participants along with brain-damaged patients will then be used to evaluate the competing theoretical approaches to conceptual representations. These findings indicate that concepts are flexible, distributed representations comprised of modality-specific conceptual features. Conceptual features are stored in distinct sensory and motor brain areas depending on specific sensory and motor experiences during concept acquisition. Three important controversial issues are highlighted, which require further clarification in future research: the existence of an amodal conceptual representation in the anterior temporal lobe, the causal role of sensory and motor activation for conceptual processing and the grounding of abstract concepts in perception and action. We argue that an embodiment view of conceptual representations realized as distributed sensory and motor cell assemblies that are complemented by supramodal integration brain circuits may serve as a theoretical framework to guide future research on concrete and abstract concepts. Copyright © 2011 Elsevier Srl. All rights reserved.

  5. Noise in attractor networks in the brain produced by graded firing rate representations

    OpenAIRE

    Webb, Tristan J.; Rolls, Edmund T; Deco, Gustavo; Feng, Jianfeng

    2011-01-01

    Representations in the cortex are often distributed with graded firing rates in the neuronal populations. The firing rate\\ud probability distribution of each neuron to a set of stimuli is often exponential or gamma. In processes in the brain, such as\\ud decision-making, that are influenced by the noise produced by the close to random spike timings of each neuron for a given\\ud mean rate, the noise with this graded type of representation may be larger than with the binary firing rate distribut...

  6. Hierarchical Neural Representation of Dreamed Objects Revealed by Brain Decoding with Deep Neural Network Features.

    Science.gov (United States)

    Horikawa, Tomoyasu; Kamitani, Yukiyasu

    2017-01-01

    Dreaming is generally thought to be generated by spontaneous brain activity during sleep with patterns common to waking experience. This view is supported by a recent study demonstrating that dreamed objects can be predicted from brain activity during sleep using statistical decoders trained with stimulus-induced brain activity. However, it remains unclear whether and how visual image features associated with dreamed objects are represented in the brain. In this study, we used a deep neural network (DNN) model for object recognition as a proxy for hierarchical visual feature representation, and DNN features for dreamed objects were analyzed with brain decoding of fMRI data collected during dreaming. The decoders were first trained with stimulus-induced brain activity labeled with the feature values of the stimulus image from multiple DNN layers. The decoders were then used to decode DNN features from the dream fMRI data, and the decoded features were compared with the averaged features of each object category calculated from a large-scale image database. We found that the feature values decoded from the dream fMRI data positively correlated with those associated with dreamed object categories at mid- to high-level DNN layers. Using the decoded features, the dreamed object category could be identified at above-chance levels by matching them to the averaged features for candidate categories. The results suggest that dreaming recruits hierarchical visual feature representations associated with objects, which may support phenomenal aspects of dream experience.

  7. How does the brain rapidly learn and reorganize view-invariant and position-invariant object representations in the inferotemporal cortex?

    Science.gov (United States)

    Cao, Yongqiang; Grossberg, Stephen; Markowitz, Jeffrey

    2011-12-01

    All primates depend for their survival on being able to rapidly learn about and recognize objects. Objects may be visually detected at multiple positions, sizes, and viewpoints. How does the brain rapidly learn and recognize objects while scanning a scene with eye movements, without causing a combinatorial explosion in the number of cells that are needed? How does the brain avoid the problem of erroneously classifying parts of different objects together at the same or different positions in a visual scene? In monkeys and humans, a key area for such invariant object category learning and recognition is the inferotemporal cortex (IT). A neural model is proposed to explain how spatial and object attention coordinate the ability of IT to learn invariant category representations of objects that are seen at multiple positions, sizes, and viewpoints. The model clarifies how interactions within a hierarchy of processing stages in the visual brain accomplish this. These stages include the retina, lateral geniculate nucleus, and cortical areas V1, V2, V4, and IT in the brain's What cortical stream, as they interact with spatial attention processes within the parietal cortex of the Where cortical stream. The model builds upon the ARTSCAN model, which proposed how view-invariant object representations are generated. The positional ARTSCAN (pARTSCAN) model proposes how the following additional processes in the What cortical processing stream also enable position-invariant object representations to be learned: IT cells with persistent activity, and a combination of normalizing object category competition and a view-to-object learning law which together ensure that unambiguous views have a larger effect on object recognition than ambiguous views. The model explains how such invariant learning can be fooled when monkeys, or other primates, are presented with an object that is swapped with another object during eye movements to foveate the original object. The swapping procedure is

  8. Neural Mechanisms Underlying Risk and Ambiguity Attitudes.

    Science.gov (United States)

    Blankenstein, Neeltje E; Peper, Jiska S; Crone, Eveline A; van Duijvenvoorde, Anna C K

    2017-11-01

    Individual differences in attitudes to risk (a taste for risk, known probabilities) and ambiguity (a tolerance for uncertainty, unknown probabilities) differentially influence risky decision-making. However, it is not well understood whether risk and ambiguity are coded differently within individuals. Here, we tested whether individual differences in risk and ambiguity attitudes were reflected in distinct neural correlates during choice and outcome processing of risky and ambiguous gambles. To these ends, we developed a neuroimaging task in which participants ( n = 50) chose between a sure gain and a gamble, which was either risky or ambiguous, and presented decision outcomes (gains, no gains). From a separate task in which the amount, probability, and ambiguity level were varied, we estimated individuals' risk and ambiguity attitudes. Although there was pronounced neural overlap between risky and ambiguous gambling in a network typically related to decision-making under uncertainty, relatively more risk-seeking attitudes were associated with increased activation in valuation regions of the brain (medial and lateral OFC), whereas relatively more ambiguity-seeking attitudes were related to temporal cortex activation. In addition, although striatum activation was observed during reward processing irrespective of a prior risky or ambiguous gamble, reward processing after an ambiguous gamble resulted in enhanced dorsomedial PFC activation, possibly functioning as a general signal of uncertainty coding. These findings suggest that different neural mechanisms reflect individual differences in risk and ambiguity attitudes and that risk and ambiguity may impact overt risk-taking behavior in different ways.

  9. Interpretation of ambiguous social scenarios in social phobia and depression: evidence from event-related brain potentials.

    Science.gov (United States)

    Moser, Jason S; Huppert, Jonathan D; Foa, Edna B; Simons, Robert F

    2012-02-01

    In the current study, event-related potentials (ERPs) and behavioral responses were measured in individuals meeting diagnostic criteria for social phobia, depression, their combination, or neither in order to examine the unique and combined effects of social phobia and depression on the interpretation of ambiguous social scenarios. ERPs revealed a lack of positive interpretation bias and some suggestion of a negative bias in the semantic expectancy N4 component across all clinical groups. Furthermore, socially phobic and comorbid individuals showed reductions in baseline attention allocation to the task, as indexed by P6 amplitude. RT and accuracy likewise revealed a lack of positive interpretation bias across disordered groups. When considered on a continuum across all samples, social phobia and depression symptoms were related to the N4 interpretation bias effect whereas P6 amplitude reduction and RT interpretation bias appeared uniquely associated with social phobia. Copyright © 2011 Elsevier B.V. All rights reserved.

  10. Dynamics of trimming the content of face representations for categorization in the brain.

    Directory of Open Access Journals (Sweden)

    Nicola J van Rijsbergen

    2009-11-01

    Full Text Available To understand visual cognition, it is imperative to determine when, how and with what information the human brain categorizes the visual input. Visual categorization consistently involves at least an early and a late stage: the occipito-temporal N170 event related potential related to stimulus encoding and the parietal P300 involved in perceptual decisions. Here we sought to understand how the brain globally transforms its representations of face categories from their early encoding to the later decision stage over the 400 ms time window encompassing the N170 and P300 brain events. We applied classification image techniques to the behavioral and electroencephalographic data of three observers who categorized seven facial expressions of emotion and report two main findings: (1 over the 400 ms time course, processing of facial features initially spreads bilaterally across the left and right occipito-temporal regions to dynamically converge onto the centro-parietal region; (2 concurrently, information processing gradually shifts from encoding common face features across all spatial scales (e.g., the eyes to representing only the finer scales of the diagnostic features that are richer in useful information for behavior (e.g., the wide opened eyes in 'fear'; the detailed mouth in 'happy'. Our findings suggest that the brain refines its diagnostic representations of visual categories over the first 400 ms of processing by trimming a thorough encoding of features over the N170, to leave only the detailed information important for perceptual decisions over the P300.

  11. Stimulating the Brain's Language Network: Syntactic Ambiguity Resolution after TMS to the Inferior Frontal Gyrus and Middle Temporal Gyrus

    NARCIS (Netherlands)

    Acheson, D.J.; Hagoort, P.

    2013-01-01

    The posterior middle temporal gyrus (MTG) and inferior frontal gyrus (IFG) are two critical nodes of the brain's language network. Previous neuroimaging evidence has supported a dissociation in language comprehension in which parts of the MTG are involved in the retrieval of lexical syntactic

  12. Resolving anatomical and functional structure in human brain organization: identifying mesoscale organization in weighted network representations.

    Science.gov (United States)

    Lohse, Christian; Bassett, Danielle S; Lim, Kelvin O; Carlson, Jean M

    2014-10-01

    Human brain anatomy and function display a combination of modular and hierarchical organization, suggesting the importance of both cohesive structures and variable resolutions in the facilitation of healthy cognitive processes. However, tools to simultaneously probe these features of brain architecture require further development. We propose and apply a set of methods to extract cohesive structures in network representations of brain connectivity using multi-resolution techniques. We employ a combination of soft thresholding, windowed thresholding, and resolution in community detection, that enable us to identify and isolate structures associated with different weights. One such mesoscale structure is bipartivity, which quantifies the extent to which the brain is divided into two partitions with high connectivity between partitions and low connectivity within partitions. A second, complementary mesoscale structure is modularity, which quantifies the extent to which the brain is divided into multiple communities with strong connectivity within each community and weak connectivity between communities. Our methods lead to multi-resolution curves of these network diagnostics over a range of spatial, geometric, and structural scales. For statistical comparison, we contrast our results with those obtained for several benchmark null models. Our work demonstrates that multi-resolution diagnostic curves capture complex organizational profiles in weighted graphs. We apply these methods to the identification of resolution-specific characteristics of healthy weighted graph architecture and altered connectivity profiles in psychiatric disease.

  13. Observability and Controllability of Networks: Symmetry in Representations of Brains and Controllers for Epidemics

    Science.gov (United States)

    Schiff, Steven

    Observability and controllability are essential concepts to the design of predictive observer models and feedback controllers of networked systems. We present a numerical and group representational framework, to quantify the observability and controllability of nonlinear networks with explicit symmetries that shows the connection between symmetries and nonlinear measures of observability and controllability. In addition to the topology of brain networks, we have advanced our ability to represent network nodes within the brain using conservation principles and more accurate biophysics that unifies the dynamics of spikes, seizures, and spreading depression. Lastly, we show how symmetries in controller design can be applied to infectious disease epidemics. NIH Grants 1R01EB014641, 1DP1HD086071.

  14. 'Love builds brains': representations of attachment and children's brain development in parenting education material.

    Science.gov (United States)

    Wall, Glenda

    2018-03-01

    A focus on early brain development has come to dominate expert child rearing advice over the past two decades. Recent scholars have noted a reinvigoration of the concept of attachment in this advice and changes in the ways that attachment is framed and understood. The extent to which the concept of attachment is drawn on, the way it is framed, and the consequences for mothers, families and parent-child relationships is examined through a discursive analysis of a current Canadian parental education campaign. Findings support the argument that attachment is receiving a great deal of attention in brain-based parenting education programmes as children's emotional development becomes increasingly prioritized. Attachment is presented as needing to be actively and continually built through expert-guided empathetic and responsive parental behaviour, and is framed as crucial for the development of brain pathways that promote emotional strength and self-regulation in children. Attachment-building is also presented as requiring highly intensive parenting that falls overwhelmingly to mothers. The parent-child relationship that is envisioned is one that is instrumental, lacking in affect and conducive to the creation of ideal self-regulating neo-liberal citizens. © 2017 Foundation for the Sociology of Health & Illness.

  15. Noise in attractor networks in the brain produced by graded firing rate representations.

    Directory of Open Access Journals (Sweden)

    Tristan J Webb

    Full Text Available Representations in the cortex are often distributed with graded firing rates in the neuronal populations. The firing rate probability distribution of each neuron to a set of stimuli is often exponential or gamma. In processes in the brain, such as decision-making, that are influenced by the noise produced by the close to random spike timings of each neuron for a given mean rate, the noise with this graded type of representation may be larger than with the binary firing rate distribution that is usually investigated. In integrate-and-fire simulations of an attractor decision-making network, we show that the noise is indeed greater for a given sparseness of the representation for graded, exponential, than for binary firing rate distributions. The greater noise was measured by faster escaping times from the spontaneous firing rate state when the decision cues are applied, and this corresponds to faster decision or reaction times. The greater noise was also evident as less stability of the spontaneous firing state before the decision cues are applied. The implication is that spiking-related noise will continue to be a factor that influences processes such as decision-making, signal detection, short-term memory, and memory recall even with the quite large networks found in the cerebral cortex. In these networks there are several thousand recurrent collateral synapses onto each neuron. The greater noise with graded firing rate distributions has the advantage that it can increase the speed of operation of cortical circuitry.

  16. Integration of sparse multi-modality representation and geometrical constraint for isointense infant brain segmentation.

    Science.gov (United States)

    Wang, Li; Shi, Feng; Li, Gang; Lin, Weili; Gilmore, John H; Shen, Dinggang

    2013-01-01

    Segmentation of infant brain MR images is challenging due to insufficient image quality, severe partial volume effect, and ongoing maturation and myelination process. During the first year of life, the signal contrast between white matter (WM) and gray matter (GM) in MR images undergoes inverse changes. In particular, the inversion of WM/GM signal contrast appears around 6-8 months of age, where brain tissues appear isointense and hence exhibit extremely low tissue contrast, posing significant challenges for automated segmentation. In this paper, we propose a novel segmentation method to address the above-mentioned challenge based on the sparse representation of the complementary tissue distribution information from T1, T2 and diffusion-weighted images. Specifically, we first derive an initial segmentation from a library of aligned multi-modality images with ground-truth segmentations by using sparse representation in a patch-based fashion. The segmentation is further refined by the integration of the geometrical constraint information. The proposed method was evaluated on 22 6-month-old training subjects using leave-one-out cross-validation, as well as 10 additional infant testing subjects, showing superior results in comparison to other state-of-the-art methods.

  17. Risk, ambiguity, and diversification

    OpenAIRE

    Sautua, Santiago-Ignacio

    2016-01-01

    Attitudes toward risk influence the decision to diversify among uncertain options. Yet, because in most situations the options are ambiguous, attitudes toward ambiguity may also play an important role. I conduct a laboratory experiment to investigate the effect of ambiguity on the decision to diversify. I find that diversification is more prevalent and more persistent under ambiguity than under risk. Moreover, excess diversification under ambiguity is driven by participants who stick with a s...

  18. Experience with adults shapes multisensory representation of social familiarity in the brain of a songbird.

    Directory of Open Access Journals (Sweden)

    Isabelle George

    Full Text Available Social animals learn to perceive their social environment, and their social skills and preferences are thought to emerge from greater exposure to and hence familiarity with some social signals rather than others. Familiarity appears to be tightly linked to multisensory integration. The ability to differentiate and categorize familiar and unfamiliar individuals and to build a multisensory representation of known individuals emerges from successive social interactions, in particular with adult, experienced models. In different species, adults have been shown to shape the social behavior of young by promoting selective attention to multisensory cues. The question of what representation of known conspecifics adult-deprived animals may build therefore arises. Here we show that starlings raised with no experience with adults fail to develop a multisensory representation of familiar and unfamiliar starlings. Electrophysiological recordings of neuronal activity throughout the primary auditory area of these birds, while they were exposed to audio-only or audiovisual familiar and unfamiliar cues, showed that visual stimuli did, as in wild-caught starlings, modulate auditory responses but that, unlike what was observed in wild-caught birds, this modulation was not influenced by familiarity. Thus, adult-deprived starlings seem to fail to discriminate between familiar and unfamiliar individuals. This suggests that adults may shape multisensory representation of known individuals in the brain, possibly by focusing the young's attention on relevant, multisensory cues. Multisensory stimulation by experienced, adult models may thus be ubiquitously important for the development of social skills (and of the neural properties underlying such skills in a variety of species.

  19. Retrieval of Brain Tumors by Adaptive Spatial Pooling and Fisher Vector Representation.

    Science.gov (United States)

    Cheng, Jun; Yang, Wei; Huang, Meiyan; Huang, Wei; Jiang, Jun; Zhou, Yujia; Yang, Ru; Zhao, Jie; Feng, Yanqiu; Feng, Qianjin; Chen, Wufan

    2016-01-01

    Content-based image retrieval (CBIR) techniques have currently gained increasing popularity in the medical field because they can use numerous and valuable archived images to support clinical decisions. In this paper, we concentrate on developing a CBIR system for retrieving brain tumors in T1-weighted contrast-enhanced MRI images. Specifically, when the user roughly outlines the tumor region of a query image, brain tumor images in the database of the same pathological type are expected to be returned. We propose a novel feature extraction framework to improve the retrieval performance. The proposed framework consists of three steps. First, we augment the tumor region and use the augmented tumor region as the region of interest to incorporate informative contextual information. Second, the augmented tumor region is split into subregions by an adaptive spatial division method based on intensity orders; within each subregion, we extract raw image patches as local features. Third, we apply the Fisher kernel framework to aggregate the local features of each subregion into a respective single vector representation and concatenate these per-subregion vector representations to obtain an image-level signature. After feature extraction, a closed-form metric learning algorithm is applied to measure the similarity between the query image and database images. Extensive experiments are conducted on a large dataset of 3604 images with three types of brain tumors, namely, meningiomas, gliomas, and pituitary tumors. The mean average precision can reach 94.68%. Experimental results demonstrate the power of the proposed algorithm against some related state-of-the-art methods on the same dataset.

  20. Five-year-olds do not show ambiguity aversion in a risk and ambiguity task with physical objects.

    Science.gov (United States)

    Li, Rosa; Roberts, Rachel C; Huettel, Scott A; Brannon, Elizabeth M

    2017-07-01

    Ambiguity aversion arises when a decision maker prefers risky gambles with known probabilities over equivalent ambiguous gambles with unknown probabilities. This phenomenon has been consistently observed in adults across a large body of empirical work. Evaluating ambiguity aversion in young children, however, has posed methodological challenges because probabilistic representations appropriate for adults might not be understood by young children. Here, we established a novel method for representing risk and ambiguity with physical objects that overcomes previous methodological limitations and allows us to measure ambiguity aversion in young children. We found that individual 5-year-olds exhibited consistent choice preferences and, as a group, exhibited no ambiguity aversion in a task that evokes ambiguity aversion in adults. Across individuals, 5-year-olds exhibited greater variance in ambiguity preferences compared with adults tested under similar conditions. This suggests that ambiguity aversion is absent during early childhood and emerges over the course of development. Copyright © 2017 Elsevier Inc. All rights reserved.

  1. Treatment decisions under ambiguity.

    Science.gov (United States)

    Berger, Loïc; Bleichrodt, Han; Eeckhoudt, Louis

    2013-05-01

    Many health risks are ambiguous in the sense that reliable and credible information about these risks is unavailable. In health economics, ambiguity is usually handled through sensitivity analysis, which implicitly assumes that people are neutral towards ambiguity. However, empirical evidence suggests that people are averse to ambiguity and react strongly to it. This paper studies the effects of ambiguity aversion on two classical medical decision problems. If there is ambiguity regarding the diagnosis of a patient, ambiguity aversion increases the decision maker's propensity to opt for treatment. On the other hand, in the case of ambiguity regarding the effects of treatment, ambiguity aversion leads to a reduction in the propensity to choose treatment. Copyright © 2013 Elsevier B.V. All rights reserved.

  2. Image Ambiguity and Fluency

    Science.gov (United States)

    Jakesch, Martina; Leder, Helmut; Forster, Michael

    2013-01-01

    Ambiguity is often associated with negative affective responses, and enjoying ambiguity seems restricted to only a few situations, such as experiencing art. Nevertheless, theories of judgment formation, especially the “processing fluency account”, suggest that easy-to-process (non-ambiguous) stimuli are processed faster and are therefore preferred to (ambiguous) stimuli, which are hard to process. In a series of six experiments, we investigated these contrasting approaches by manipulating fluency (presentation duration: 10ms, 50ms, 100ms, 500ms, 1000ms) and testing effects of ambiguity (ambiguous versus non-ambiguous pictures of paintings) on classification performance (Part A; speed and accuracy) and aesthetic appreciation (Part B; liking and interest). As indicated by signal detection analyses, classification accuracy increased with presentation duration (Exp. 1a), but we found no effects of ambiguity on classification speed (Exp. 1b). Fifty percent of the participants were able to successfully classify ambiguous content at a presentation duration of 100 ms, and at 500ms even 75% performed above chance level. Ambiguous artworks were found more interesting (in conditions 50ms to 1000ms) and were preferred over non-ambiguous stimuli at 500ms and 1000ms (Exp. 2a - 2c, 3). Importantly, ambiguous images were nonetheless rated significantly harder to process as non-ambiguous images. These results suggest that ambiguity is an essential ingredient in art appreciation even though or maybe because it is harder to process. PMID:24040172

  3. Decomposing Gratitude: Representation and Integration of Cognitive Antecedents of Gratitude in the Brain.

    Science.gov (United States)

    Yu, Hongbo; Gao, Xiaoxue; Zhou, Yuanyuan; Zhou, Xiaolin

    2018-05-23

    Gratitude is a typical social-moral emotion that plays a crucial role in maintaining human cooperative interpersonal relationship. Although neural correlates of gratitude have been investigated, the neurocognitive processes that lead to gratitude, namely, the representation and integration of its cognitive antecedents, remain largely unknown. Here, we combined fMRI and a human social interactive task to investigate how benefactor's cost and beneficiary's benefit, two critical antecedents of gratitude, are encoded and integrated in beneficiary's brain, and how the neural processing of gratitude is converted to reciprocity. A coplayer decided whether to help a human participant (either male or female) avoid pain at his/her own monetary cost; the participants could transfer monetary points to the benefactor with the knowledge that the benefactor was unaware of this transfer. By independently manipulating monetary cost and the degree of pain reduction, we could identify the neural signatures of benefactor's cost and recipient's benefit and examine how they were integrated. Recipient's self-benefit was encoded in reward-sensitive regions (e.g., ventral striatum), whereas benefactor-cost was encoded in regions associated with mentalizing (e.g., temporoparietal junction). Gratitude was represented in perigenual anterior cingulate cortex (pgACC), the strength of which correlated with trait gratitude. Dynamic causal modeling showed that the neural signals representing benefactor-cost and self-benefit passed to pgACC via effective connectivities, suggesting an integrative role of pgACC in generating gratitude. Moreover, gyral ACC plays an intermediary role in converting gratitude representation into reciprocal behaviors. Our findings provide a neural mechanistic account of gratitude and its role in social-moral life. SIGNIFICANCE STATEMENT Gratitude plays an integral role in subjective well-being and harmonious interpersonal relationships. However, the neurocognitive

  4. Explain the 'unexplainable': A qualitative enquiry of the representations of the caregivers of brain-injured people.

    Science.gov (United States)

    Huet, Magali; Dany, Lionel; Apostolidis, Thémistoklis

    2016-04-01

    The aim of our research is to highlight the role of social representations of the traumatic brain-injured person in the adjustments made by caregivers in building and maintaining quality of care. Twenty-three semi-structured interviews were conducted with nursing assistants and medico-psychological assistants, working in a long-term care facility. The interviews were the subject of a thematic content analysis. The analysis shows the role of representations of the traumatic brain-injured person in the way caregivers explain behaviours and situations and in the orientation of their professional practices. In explaining the inexplicable, caregivers establish a more human relationship through individualized care.

  5. Different brain circuits underlie motor and perceptual representations of temporal intervals

    DEFF Research Database (Denmark)

    Bueti, Doemnica; Walsh, Vincent; Frith, Christopher

    2008-01-01

    V5/MT. Our findings point to a role for the parietal cortex as an interface between sensory and motor processes and suggest that it may be a key node in translation of temporal information into action. Furthermore, we discuss the potential importance of the extrastriate cortex in processing visual......In everyday life, temporal information is used for both perception and action, but whether these two functions reflect the operation of similar or different neural circuits is unclear. We used functional magnetic resonance imaging to investigate the neural correlates of processing temporal...... information when either a motor or a perceptual representation is used. Participants viewed two identical sequences of visual stimuli and used the information differently to perform either a temporal reproduction or a temporal estimation task. By comparing brain activity evoked by these tasks and control...

  6. How does the body representation system develop in the human brain?

    Science.gov (United States)

    Fontan, Aurelie; Cignetti, Fabien; Nazarian, Bruno; Anton, Jean-Luc; Vaugoyeau, Marianne; Assaiante, Christine

    2017-04-01

    Exploration of the body representation system (BRS) from kinaesthetic illusions in fMRI has revealed a complex network composed of sensorimotor and frontoparietal components. Here, we evaluated the degree of maturity of this network in children aged 7-11 years, and the extent to which structural factors account for network differences with adults. Brain activation following tendon vibration at 100Hz ('illusion') and 30Hz ('no illusion') were analysed using the two-stage random effects model, with or without white and grey matter covariates. The BRS was already well established in children as revealed by the contrast 'illusion' vs 'no illusion', although still immature in some aspects. This included a lower level of activation in primary somatosensory and posterior parietal regions, and the exclusive activation of the frontopolar cortex (FPC) in children compared to adults. The former differences were related to structure, while the latter difference reflected a functional strategy where the FPC may serve as the 'top' in top-down modulation of the activity of the other BRS regions to facilitate the establishment of body representations. Hence, the development of the BRS not only relies on structural maturation, but also involves the disengagement of an executive region not classically involved in body processing. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

  7. Neural Correlates of Decision-Making Under Ambiguity and Conflict.

    Science.gov (United States)

    Pushkarskaya, Helen; Smithson, Michael; Joseph, Jane E; Corbly, Christine; Levy, Ifat

    2015-01-01

    HIGHLIGHTS We use a simple gambles design in an fMRI study to compare two conditions: ambiguity and conflict.Participants were more conflict averse than ambiguity averse.Ambiguity aversion did not correlate with conflict aversion.Activation in the medial prefrontal cortex correlated with ambiguity level and ambiguity aversion.Activation in the ventral striatum correlated with conflict level and conflict aversion. Studies of decision making under uncertainty generally focus on imprecise information about outcome probabilities ("ambiguity"). It is not clear, however, whether conflicting information about outcome probabilities affects decision making in the same manner as ambiguity does. Here we combine functional magnetic resonance imaging (fMRI) and a simple gamble design to study this question. In this design the levels of ambiguity and conflict are parametrically varied, and ambiguity and conflict gambles are matched on expected value. Behaviorally, participants avoided conflict more than ambiguity, and attitudes toward ambiguity and conflict did not correlate across participants. Neurally, regional brain activation was differentially modulated by ambiguity level and aversion to ambiguity and by conflict level and aversion to conflict. Activation in the medial prefrontal cortex was correlated with the level of ambiguity and with ambiguity aversion, whereas activation in the ventral striatum was correlated with the level of conflict and with conflict aversion. These novel results indicate that decision makers process imprecise and conflicting information differently, a finding that has important implications for basic and clinical research.

  8. View-Independent Working Memory Representations of Artificial Shapes in Prefrontal and Posterior Regions of the Human Brain.

    Science.gov (United States)

    Christophel, Thomas B; Allefeld, Carsten; Endisch, Christian; Haynes, John-Dylan

    2017-05-13

    Traditional views of visual working memory postulate that memorized contents are stored in dorsolateral prefrontal cortex using an adaptive and flexible code. In contrast, recent studies proposed that contents are maintained by posterior brain areas using codes akin to perceptual representations. An important question is whether this reflects a difference in the level of abstraction between posterior and prefrontal representations. Here, we investigated whether neural representations of visual working memory contents are view-independent, as indicated by rotation-invariance. Using functional magnetic resonance imaging and multivariate pattern analyses, we show that when subjects memorize complex shapes, both posterior and frontal brain regions maintain the memorized contents using a rotation-invariant code. Importantly, we found the representations in frontal cortex to be localized to the frontal eye fields rather than dorsolateral prefrontal cortices. Thus, our results give evidence for the view-independent storage of complex shapes in distributed representations across posterior and frontal brain regions. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  9. Distinct contributions of functional and deep neural network features to representational similarity of scenes in human brain and behavior.

    Science.gov (United States)

    Groen, Iris Ia; Greene, Michelle R; Baldassano, Christopher; Fei-Fei, Li; Beck, Diane M; Baker, Chris I

    2018-03-07

    Inherent correlations between visual and semantic features in real-world scenes make it difficult to determine how different scene properties contribute to neural representations. Here, we assessed the contributions of multiple properties to scene representation by partitioning the variance explained in human behavioral and brain measurements by three feature models whose inter-correlations were minimized a priori through stimulus preselection. Behavioral assessments of scene similarity reflected unique contributions from a functional feature model indicating potential actions in scenes as well as high-level visual features from a deep neural network (DNN). In contrast, similarity of cortical responses in scene-selective areas was uniquely explained by mid- and high-level DNN features only, while an object label model did not contribute uniquely to either domain. The striking dissociation between functional and DNN features in their contribution to behavioral and brain representations of scenes indicates that scene-selective cortex represents only a subset of behaviorally relevant scene information.

  10. Risk, ambiguity and sovereign rating

    OpenAIRE

    Di Caro, Paolo

    2014-01-01

    Decisions of investing in sovereign assets involve both risk and ambiguity. Ambiguity arises from unknown elements characterizing the value of a generic sovereign. In presence of ambiguity, ambiguity-averse investors are prone to pay for obtaining summary information such as ratings which reduces ambiguity. Ambiguity-neutral and ambiguity-averse investors, then, make decisions on the basis of different informative sources. By presenting a simple model of sovereign rating under ambiguity, thre...

  11. The application of brain-based learning principles aided by GeoGebra to improve mathematical representation ability

    Science.gov (United States)

    Priatna, Nanang

    2017-08-01

    The use of Information and Communication Technology (ICT) in mathematics instruction will help students in building conceptual understanding. One of the software products used in mathematics instruction is GeoGebra. The program enables simple visualization of complex geometric concepts and helps improve students' understanding of geometric concepts. Instruction applying brain-based learning principles is one oriented at the efforts of naturally empowering the brain potentials which enable students to build their own knowledge. One of the goals of mathematics instruction in school is to develop mathematical communication ability. Mathematical representation is regarded as a part of mathematical communication. It is a description, expression, symbolization, or modeling of mathematical ideas/concepts as an attempt of clarifying meanings or seeking for solutions to the problems encountered by students. The research aims to develop a learning model and teaching materials by applying the principles of brain-based learning aided by GeoGebra to improve junior high school students' mathematical representation ability. It adopted a quasi-experimental method with the non-randomized control group pretest-posttest design and the 2x3 factorial model. Based on analysis of the data, it is found that the increase in the mathematical representation ability of students who were treated with mathematics instruction applying the brain-based learning principles aided by GeoGebra was greater than the increase of the students given conventional instruction, both as a whole and based on the categories of students' initial mathematical ability.

  12. An approach to the symbolic representation of brain arteriovenous malformations for management and treatment planning

    Energy Technology Data Exchange (ETDEWEB)

    Orlowski, Piotr; Noble, Alison [University of Oxford, Institute of Biomedical Engineering, Department of Engineering Science, Oxford (United Kingdom); Mahmud, Imran; Kamran, Mudassar; Byrne, James V. [University of Oxford, John Radcliffe Hospital, Nuffield Department of Surgical Sciences, Oxford (United Kingdom); Summers, Paul [University of Oxford, John Radcliffe Hospital, Nuffield Department of Surgical Sciences, Oxford (United Kingdom); University of Modena and Reggio Emilia, Department of Biomedical, Metabolic and Neural Sciences, Modena (Italy); Ventikos, Yiannis [University College London, Department of Mechanical Engineering, London (United Kingdom)

    2014-03-15

    There is currently no standardised approach to arteriovenous malformation (AVM) reporting. Existing AVM classification systems focuses on angioarchitectural features and omit haemodynamic, anatomical and topological parameters intuitively used by therapists. We introduce a symbolic vocabulary to represent the state of an AVM of the brain at different stages of treatment. The vocabulary encompasses the main anatomic and haemodynamic features of interest in treatment planning and provides shorthand symbols to represent the interventions themselves in a schematic representation. The method was presented to 50 neuroradiologists from14 countries during a workshop and graded 7.34 ± 1.92 out of ten for its usefulness as means of standardising and facilitating communication between clinicians and allowing comparisons between AVM cases. Feedback from the survey was used to revise the method and improve its completeness. For an AVM test case, participants were asked to produce a conventional written report and subsequently a diagrammatic report. The two required, on average, 6.19 ± 2.05 and 5.09 ± 3.01 min, respectively. Eighteen participants said that producing the diagram changed the way they thought about the AVM test case. Introduced into routine practice, the diagrams would represent a step towards a standardised approach to AVM reporting with consequent benefits for comparative analysis and communication as well as for identifying best treatment strategies. (orig.)

  13. Simple adaptive sparse representation based classification schemes for EEG based brain-computer interface applications.

    Science.gov (United States)

    Shin, Younghak; Lee, Seungchan; Ahn, Minkyu; Cho, Hohyun; Jun, Sung Chan; Lee, Heung-No

    2015-11-01

    One of the main problems related to electroencephalogram (EEG) based brain-computer interface (BCI) systems is the non-stationarity of the underlying EEG signals. This results in the deterioration of the classification performance during experimental sessions. Therefore, adaptive classification techniques are required for EEG based BCI applications. In this paper, we propose simple adaptive sparse representation based classification (SRC) schemes. Supervised and unsupervised dictionary update techniques for new test data and a dictionary modification method by using the incoherence measure of the training data are investigated. The proposed methods are very simple and additional computation for the re-training of the classifier is not needed. The proposed adaptive SRC schemes are evaluated using two BCI experimental datasets. The proposed methods are assessed by comparing classification results with the conventional SRC and other adaptive classification methods. On the basis of the results, we find that the proposed adaptive schemes show relatively improved classification accuracy as compared to conventional methods without requiring additional computation. Copyright © 2015 Elsevier Ltd. All rights reserved.

  14. An approach to the symbolic representation of brain arteriovenous malformations for management and treatment planning

    International Nuclear Information System (INIS)

    Orlowski, Piotr; Noble, Alison; Mahmud, Imran; Kamran, Mudassar; Byrne, James V.; Summers, Paul; Ventikos, Yiannis

    2014-01-01

    There is currently no standardised approach to arteriovenous malformation (AVM) reporting. Existing AVM classification systems focuses on angioarchitectural features and omit haemodynamic, anatomical and topological parameters intuitively used by therapists. We introduce a symbolic vocabulary to represent the state of an AVM of the brain at different stages of treatment. The vocabulary encompasses the main anatomic and haemodynamic features of interest in treatment planning and provides shorthand symbols to represent the interventions themselves in a schematic representation. The method was presented to 50 neuroradiologists from14 countries during a workshop and graded 7.34 ± 1.92 out of ten for its usefulness as means of standardising and facilitating communication between clinicians and allowing comparisons between AVM cases. Feedback from the survey was used to revise the method and improve its completeness. For an AVM test case, participants were asked to produce a conventional written report and subsequently a diagrammatic report. The two required, on average, 6.19 ± 2.05 and 5.09 ± 3.01 min, respectively. Eighteen participants said that producing the diagram changed the way they thought about the AVM test case. Introduced into routine practice, the diagrams would represent a step towards a standardised approach to AVM reporting with consequent benefits for comparative analysis and communication as well as for identifying best treatment strategies. (orig.)

  15. Computational Humour : Utilizing Cross-Reference Ambiguity for Conversational Jokes

    NARCIS (Netherlands)

    Tinholt, Hans Wim; Nijholt, Anton; Masulli, Francesco; Mitra, Sushmita; Pasi, Gabriella

    2007-01-01

    This paper presents a computer implementation that utilizes cross-reference ambiguity in utterances for simple conversational jokes. The approach is based on the SSTH. Using a simple script representation, it is shown that cross-reference ambiguities always satisfy the SSTH requirement for script

  16. Measuring higher order ambiguity preferences.

    Science.gov (United States)

    Baillon, Aurélien; Schlesinger, Harris; van de Kuilen, Gijs

    2018-01-01

    We report the results from an experiment designed to measure attitudes towards ambiguity beyond ambiguity aversion. In particular, we implement recently-proposed model-free preference conditions of ambiguity prudence and ambiguity temperance. Ambiguity prudence has been shown to play an important role in precautionary behavior and the mere presence of ambiguity averse agents in markets. We observe that the majority of individuals' decisions are consistent with ambiguity aversion, ambiguity prudence and ambiguity temperance. This finding confirms the prediction of many popular (specifications of) ambiguity models and has important implications for models of prevention behavior.

  17. Properties of Ambiguity Functions

    OpenAIRE

    Mulcahy-Stanislawczyk, John

    2014-01-01

    The use of ambiguity functions in radar signal design and analysis is very common. Understanding the various properties and meanings of ambiguity functions allow a signal designer to understand the time delay and doppler shift properties of a given signal. Through the years, several different versions of the ambiguity function have been used. Each of these functions essentially have the same physical meaning; however, the use of different functions makes it difficult to be sure that certai...

  18. Body representations in the human brain revealed by kinesthetic illusions and their essential contributions to motor control and corporeal awareness.

    Science.gov (United States)

    Naito, Eiichi; Morita, Tomoyo; Amemiya, Kaoru

    2016-03-01

    The human brain can generate a continuously changing postural model of our body. Somatic (proprioceptive) signals from skeletal muscles and joints contribute to the formation of the body representation. Recent neuroimaging studies of proprioceptive bodily illusions have elucidated the importance of three brain systems (motor network, specialized parietal systems, right inferior fronto-parietal network) in the formation of the human body representation. The motor network, especially the primary motor cortex, processes afferent input from skeletal muscles. Such information may contribute to the formation of kinematic/dynamic postural models of limbs, thereby enabling fast online feedback control. Distinct parietal regions appear to play specialized roles in the transformation/integration of information across different coordinate systems, which may subserve the adaptability and flexibility of the body representation. Finally, the right inferior fronto-parietal network, connected by the inferior branch of the superior longitudinal fasciculus, is consistently recruited when an individual experiences various types of bodily illusions and its possible roles relate to corporeal awareness, which is likely elicited through a series of neuronal processes of monitoring and accumulating bodily information and updating the body representation. Because this network is also recruited when identifying one's own features, the network activity could be a neuronal basis for self-consciousness. Copyright © 2015 Elsevier Ireland Ltd and the Japan Neuroscience Society. All rights reserved.

  19. Vignettes of Ambiguity

    Science.gov (United States)

    Gotz, Ignacio L.

    2010-01-01

    This article is an exploration of ambiguity as it appears in various guises in philosophical, social, political, and educational situations. Among these situations is the experience of exile. The exploration is conducted by means of literary anecdotes and real-life instances, hence the use of vignettes. The suggestion is made that ambiguity can be…

  20. Determinants of translation ambiguity

    Science.gov (United States)

    Degani, Tamar; Prior, Anat; Eddington, Chelsea M.; Arêas da Luz Fontes, Ana B.; Tokowicz, Natasha

    2016-01-01

    Ambiguity in translation is highly prevalent, and has consequences for second-language learning and for bilingual lexical processing. To better understand this phenomenon, the current study compared the determinants of translation ambiguity across four sets of translation norms from English to Spanish, Dutch, German and Hebrew. The number of translations an English word received was correlated across these different languages, and was also correlated with the number of senses the word has in English, demonstrating that translation ambiguity is partially determined by within-language semantic ambiguity. For semantically-ambiguous English words, the probability of the different translations in Spanish and Hebrew was predicted by the meaning-dominance structure in English, beyond the influence of other lexical and semantic factors, for bilinguals translating from their L1, and translating from their L2. These findings are consistent with models postulating direct access to meaning from L2 words for moderately-proficient bilinguals. PMID:27882188

  1. The Ethics of Ambiguity

    Directory of Open Access Journals (Sweden)

    Ronald E. Domen MD

    2016-06-01

    Full Text Available Understanding and embracing uncertainty are critical for effective teacher–learner relationships as well as for shared decision-making in the physician–patient relationship. However, ambiguity has not been given serious consideration in either the undergraduate or graduate medical curricula or in the role it plays in patient-centered care. In this article, the author examines the ethics of ambiguity and argues for a pedagogy that includes education in the importance of, and tolerance of, ambiguity that is inherent in medical education and practice. Common threads running through the ethics of ambiguity are the virtue of respect, and the development of a culture of respect is required for the successful understanding and implementation of a pedagogy of ambiguity.

  2. The Ethics of Ambiguity

    Science.gov (United States)

    2016-01-01

    Understanding and embracing uncertainty are critical for effective teacher–learner relationships as well as for shared decision-making in the physician–patient relationship. However, ambiguity has not been given serious consideration in either the undergraduate or graduate medical curricula or in the role it plays in patient-centered care. In this article, the author examines the ethics of ambiguity and argues for a pedagogy that includes education in the importance of, and tolerance of, ambiguity that is inherent in medical education and practice. Common threads running through the ethics of ambiguity are the virtue of respect, and the development of a culture of respect is required for the successful understanding and implementation of a pedagogy of ambiguity. PMID:28725771

  3. Measuring higher order ambiguity preferences

    NARCIS (Netherlands)

    A. Baillon (Aurélien); Schlesinger, H. (Harris); G. van de Kuilen (Gijs)

    2017-01-01

    textabstractWe report the results from an experiment designed to measure attitudes towards ambiguity beyond ambiguity aversion. In particular, we implement recently-proposed model-free preference conditions of ambiguity prudence and ambiguity temperance. Ambiguity prudence has been shown to play an

  4. A Neural Signature Encoding Decisions under Perceptual Ambiguity.

    Science.gov (United States)

    Sun, Sai; Yu, Rongjun; Wang, Shuo

    2017-01-01

    People often make perceptual decisions with ambiguous information, but it remains unclear whether the brain has a common neural substrate that encodes various forms of perceptual ambiguity. Here, we used three types of perceptually ambiguous stimuli as well as task instructions to examine the neural basis for both stimulus-driven and task-driven perceptual ambiguity. We identified a neural signature, the late positive potential (LPP), that encoded a general form of stimulus-driven perceptual ambiguity. In addition to stimulus-driven ambiguity, the LPP was also modulated by ambiguity in task instructions. To further specify the functional role of the LPP and elucidate the relationship between stimulus ambiguity, behavioral response, and the LPP, we employed regression models and found that the LPP was specifically associated with response latency and confidence rating, suggesting that the LPP encoded decisions under perceptual ambiguity. Finally, direct behavioral ratings of stimulus and task ambiguity confirmed our neurophysiological findings, which could not be attributed to differences in eye movements either. Together, our findings argue for a common neural signature that encodes decisions under perceptual ambiguity but is subject to the modulation of task ambiguity. Our results represent an essential first step toward a complete neural understanding of human perceptual decision making.

  5. United we sense, divided we fail: context-driven perception of ambiguous visual stimuli.

    NARCIS (Netherlands)

    Klink, P.C.; van Wezel, R.J.A.; van Ee, R.

    2012-01-01

    Ambiguous visual stimuli provide the brain with sensory information that contains conflicting evidence for multiple mutually exclusive interpretations. Two distinct aspects of the phenomenological experience associated with viewing ambiguous visual stimuli are the apparent stability of perception

  6. United we sense, divided we fail: context-driven perception of ambiguous visual stimuli

    NARCIS (Netherlands)

    Klink, P. C; van Wezel, Richard Jack Anton; van Ee, R.

    2012-01-01

    Ambiguous visual stimuli provide the brain with sensory information that contains conflicting evidence for multiple mutually exclusive interpretations. Two distinct aspects of the phenomenological experience associated with viewing ambiguous visual stimuli are the apparent stability of perception

  7. Information Compression, Multiple Alignment, and the Representation and Processing of Knowledge in the Brain.

    Science.gov (United States)

    Wolff, J Gerard

    2016-01-01

    The SP theory of intelligence , with its realization in the SP computer model , aims to simplify and integrate observations and concepts across artificial intelligence, mainstream computing, mathematics, and human perception and cognition, with information compression as a unifying theme. This paper describes how abstract structures and processes in the theory may be realized in terms of neurons, their interconnections, and the transmission of signals between neurons. This part of the SP theory- SP-neural -is a tentative and partial model for the representation and processing of knowledge in the brain. Empirical support for the SP theory-outlined in the paper-provides indirect support for SP-neural. In the abstract part of the SP theory (SP-abstract), all kinds of knowledge are represented with patterns , where a pattern is an array of atomic symbols in one or two dimensions. In SP-neural, the concept of a "pattern" is realized as an array of neurons called a pattern assembly , similar to Hebb's concept of a "cell assembly" but with important differences. Central to the processing of information in SP-abstract is information compression via the matching and unification of patterns (ICMUP) and, more specifically, information compression via the powerful concept of multiple alignment , borrowed and adapted from bioinformatics. Processes such as pattern recognition, reasoning and problem solving are achieved via the building of multiple alignments, while unsupervised learning is achieved by creating patterns from sensory information and also by creating patterns from multiple alignments in which there is a partial match between one pattern and another. It is envisaged that, in SP-neural, short-lived neural structures equivalent to multiple alignments will be created via an inter-play of excitatory and inhibitory neural signals. It is also envisaged that unsupervised learning will be achieved by the creation of pattern assemblies from sensory information and from the

  8. Information Compression, Multiple Alignment, and the Representation and Processing of Knowledge in the Brain

    Directory of Open Access Journals (Sweden)

    James Gerard Wolff

    2016-11-01

    Full Text Available The SP theory of intelligence, with its realisation in the SP computer model, aims to simplify and integrate observations and concepts across artificial intelligence, mainstream computing, mathematics, and human perception and cognition, with information compression as a unifying theme. This paper describes how abstract structures and processes in the theory may be realised in terms of neurons, their interconnections, and the transmission of signals between neurons. This part of the SP theory -- SP-neural -- is a tentative and partial model for the representation and processing of knowledge in the brain. Empirical support for the SP theory -- outlined in the paper -- provides indirect support for SP-neural.In the abstract part of the SP theory (SP-abstract, all kinds of knowledge are represented with patterns, where a pattern is an array of atomic symbols in one or two dimensions. In SP-neural, the concept of a ‘pattern’ is realised as an array of neurons called a pattern assembly, similar to Hebb's concept of a ‘cell assembly’ but with important differences.Central to the processing of information in SP-abstract is information compression via the matching and unification of patterns (ICMUP and, more specifically, information compression via the powerful concept of multiple alignment, borrowed and adapted from bioinformatics. Processes such as pattern recognition, reasoning and problem solving are achieved via the building of multiple alignments, while unsupervised learning is achieved by creating patterns from sensory information and also by creating patterns from multiple alignments in which there is a partial match between one pattern and another.It is envisaged that, in SP-neural, short-lived neural structures equivalent to multiple alignments will be created via an inter-play of excitatory and inhibitory neural signals. It is also envisaged that unsupervised learning will be achieved by the creation of pattern assemblies from

  9. Localizing Expression of Ambiguity

    National Research Council Canada - National Science Library

    Bear, John; Hobbs, Sr, Jerry R

    1987-01-01

    In this paper we describe an implemented program for localizing the expression of many types of syntactic ambiguity, in the logical forms of sentences, in a manner convenient for subsequent inferential processing...

  10. Exploring ambiguous realms

    DEFF Research Database (Denmark)

    Clemensen, Nana

    2016-01-01

    In Hang'ombe Village in rural Zambia, the relative lack of physical boundaries between the activities of family members allow children to observe the actions and discussions of adults on close hand, exposing them to the ambiguities of daily life. Children explore these ambiguities in their intera...... in their interactions, testing social roles and conventions. This article explores the vigilance and creative agency displayed by Hang'ombe children, in an environment spurring their acquisition of distinct social and discursive skills.......In Hang'ombe Village in rural Zambia, the relative lack of physical boundaries between the activities of family members allow children to observe the actions and discussions of adults on close hand, exposing them to the ambiguities of daily life. Children explore these ambiguities...

  11. Risk, Ambiguity, and Insurance.

    Science.gov (United States)

    1984-10-01

    California felt that once a severe earthquake occurs, it is le likely to occur in the near future (Kunreuther et al., 1978). When probabilities are...psychological model of how people assess probabilities In ambiguous circumstances. This model is based on three principles : (1) In assessing an ambiguous...TECHNICAL REPORTS DISTRIBUTION LIST 050 Department of the Navy CAPT Paul R. Chatelier Dr. Andrew Rachnitser Office of the Deputy Under Secretary Office of

  12. Motion discrimination under uncertainty and ambiguity.

    NARCIS (Netherlands)

    Kalisvaart, J.P.; Klaver, I.; Goossens, J.

    2011-01-01

    Speed and accuracy of visual motion discrimination depend systematically on motion strength. This behavior is traditionally explained by diffusion models that assume accumulation of sensory evidence over time to a decision bound. However, how does the brain decide when sensory evidence is ambiguous,

  13. Regularization ambiguities in loop quantum gravity

    International Nuclear Information System (INIS)

    Perez, Alejandro

    2006-01-01

    One of the main achievements of loop quantum gravity is the consistent quantization of the analog of the Wheeler-DeWitt equation which is free of ultraviolet divergences. However, ambiguities associated to the intermediate regularization procedure lead to an apparently infinite set of possible theories. The absence of an UV problem--the existence of well-behaved regularization of the constraints--is intimately linked with the ambiguities arising in the quantum theory. Among these ambiguities is the one associated to the SU(2) unitary representation used in the diffeomorphism covariant 'point-splitting' regularization of the nonlinear functionals of the connection. This ambiguity is labeled by a half-integer m and, here, it is referred to as the m ambiguity. The aim of this paper is to investigate the important implications of this ambiguity. We first study 2+1 gravity (and more generally BF theory) quantized in the canonical formulation of loop quantum gravity. Only when the regularization of the quantum constraints is performed in terms of the fundamental representation of the gauge group does one obtain the usual topological quantum field theory as a result. In all other cases unphysical local degrees of freedom arise at the level of the regulated theory that conspire against the existence of the continuum limit. This shows that there is a clear-cut choice in the quantization of the constraints in 2+1 loop quantum gravity. We then analyze the effects of the ambiguity in 3+1 gravity exhibiting the existence of spurious solutions for higher representation quantizations of the Hamiltonian constraint. Although the analysis is not complete in 3+1 dimensions - due to the difficulties associated to the definition of the physical inner product - it provides evidence supporting the definitions quantum dynamics of loop quantum gravity in terms of the fundamental representation of the gauge group as the only consistent possibilities. If the gauge group is SO(3) we find

  14. Ontology: ambiguity and accuracy

    Directory of Open Access Journals (Sweden)

    Marcelo Schiessl

    2012-08-01

    Full Text Available Ambiguity is a major obstacle to information retrieval. It is source of several researches in Information Science. Ontologies have been studied in order to solve problems related to ambiguities. Paradoxically, “ontology” term is also ambiguous and it is understood according to the use by the community. Philosophy and Computer Science seems to have the most accentuated difference related to the term sense. The former holds undisputed tradition and authority. The latter, in despite of being quite recent, holds an informal sense, but pragmatic. Information Science acts ranging from philosophical to computational approaches so as to get organized collections based on balance between users’ necessities and available information. The semantic web requires informational cycle automation and demands studies related to ontologies. Consequently, revisiting relevant approaches for the study of ontologies plays a relevant role as a way to provide useful ideas to researchers maintaining philosophical rigor, and convenience provided by computers.

  15. Lexical ambiguity resolution

    Energy Technology Data Exchange (ETDEWEB)

    Small, S.; Cottrell, G.; Tanenhaus, M.

    1987-01-01

    This book collects much of the best research currently available on the problem of lexical ambiguity resolution in the processing of human language. When taken out of context, sentences are usually ambiguous. When actually uttered in a dialogue or written in text, these same sentences often have unique interpretations. The inherent ambiguity of isolated sentences, becomes obvious in the attempt to write a computer program to understand them. Different views have emerged on the nature of context and the mechanisms by which it directs unambiguous understanding of words and sentences. These perspectives are represented and discussed. Eighteen original papers from a valuable source book for cognitive scientists in AI, psycholinguistics, neuropsychology, or theoretical linguistics.

  16. Representational uncertainty in the brain during threat conditioning and the link with psychopathic traits

    NARCIS (Netherlands)

    Brazil, I.A.; Mathys, C.D.; Popma, A.; Hoppenbrouwers, S.S.; Cohn, M.D.

    2017-01-01

    Background: Psychopathy has repeatedly been linked to disturbed associative learning from aversive events (i.e., threat conditioning). Optimal threat conditioning requires the generation of internal representations of stimulus-outcome contingencies and the rate with which these may change. Because

  17. The processing of lexical ambiguity in healthy ageing and Parkinson׳s disease: role of cortico-subcortical networks.

    Science.gov (United States)

    Ketteler, Simon; Ketteler, Daniel; Vohn, René; Kastrau, Frank; Schulz, Jörg B; Reetz, Kathrin; Huber, Walter

    2014-09-18

    Previous neuroimaging studies showed that correct resolution of lexical ambiguity relies on the integrity of prefrontal and inferior parietal cortices. Whereas prefrontal brain areas were associated with executive control over semantic selection, inferior parietal areas were linked with access to modality-independent representations of semantic memory. Yet insufficiently understood is the contribution of subcortical structures in ambiguity processing. Patients with disturbed basal ganglia function such as Parkinson׳s disease (PD) showed development of discourse comprehension deficits evoked by lexical ambiguity. To further investigate the engagement of cortico-subcortical networks functional Magnetic Resonance Imaging (fMRI) was monitored during ambiguity resolution in eight early PD patients without dementia and 14 age- and education-matched controls. Participants were required to relate meanings to a lexically ambiguous target (homonym). Each stimulus consisted of two words arranged on top of a screen, which had to be attributed to a homonym at the bottom. Brain activity was found in bilateral inferior parietal (BA 39), right middle temporal (BA 21/22), left middle frontal (BA 10) and bilateral inferior frontal areas (BA 45/46). Extent and amplitude of activity in the angular gyrus changed depending on semantic association strength that varied between conditions. Less activity in the left caudate was associated with semantic integration deficits in PD. The results of the present study suggest a relationship between subtle language deficits and early stages of basal ganglia dysfunction. Uncovering impairments in ambiguity resolution may be of future use in the neuropsychological assessment of non-motor deficits in PD. Copyright © 2014 Elsevier B.V. All rights reserved.

  18. De morseir syndrome presenting as ambiguous genitalia.

    Science.gov (United States)

    Thukral, Anubhav; Chitra, S; Chakraborty, Partho P; Roy, Ajitesh; Goswami, Soumik; Bhattacharjee, Rana; Dutta, Deep; Maisnam, Indira; Ghosh, Sujoy; Mukherjee, Satinath; Chowdhury, Subhankar

    2012-12-01

    A 10-year-old boy presented with genital ambiguity, poor linear growth, and delayed milestones. The aim and to highlight that although rare but congenital, hypogonadotropic hypogonadism may rarely present as ambiguity. The patient was found to have bilateral cryptorchidism with proximal penile hypospadias, microphallus with a proportionate dwarfism with mildly delayed bone age, and karyotype 46XY. Euthyroid with normal steroid axis, growth hormone insufficient as suggested by auxology, low IGF1, and poor response to clonidine stimulation. MRI brain shows hypoplastic corpus callosum, hypoplastic anterior pituitary, and ectopic posterior pituitary bright spot. The patient underwent laparoscopic removal of right intrabdominal testis and orchidoplexy was performed on the left one. Testicular biopsy revealed no malignancy and growth hormone replacement was initiated. The patient awaits definitive repair of hypospadias. As a provisional diagnosis of combined growth hormone and gonadotropin deficiency, most probable diagnosis is septo-optic dysplasia or de moseir syndrome leading to genital ambiguity.

  19. Integration of Sparse Multi-modality Representation and Geometrical Constraint for Isointense Infant Brain Segmentation

    OpenAIRE

    Wang, Li; Shi, Feng; Li, Gang; Lin, Weili; Gilmore, John H.; Shen, Dinggang

    2013-01-01

    Segmentation of infant brain MR images is challenging due to insufficient image quality, severe partial volume effect, and ongoing maturation and myelination process. During the first year of life, the signal contrast between white matter (WM) and gray matter (GM) in MR images undergoes inverse changes. In particular, the inversion of WM/GM signal contrast appears around 6–8 months of age, where brain tissues appear isointense and hence exhibit extremely low tissue contrast, posing significan...

  20. Constraints and Ambiguity

    DEFF Research Database (Denmark)

    Dove, Graham; Biskjær, Michael Mose; Lundqvist, Caroline Emilie

    2017-01-01

    groups of students building three models each. We studied groups building with traditional plastic bricks and also using a digital environment. The building tasks students undertake, and our subsequent analysis, are informed by the role constraints and ambiguity play in creative processes. Based...

  1. Ambiguity in urban belonging

    DEFF Research Database (Denmark)

    Koefoed, Lasse Martin; Simonsen, Kirsten

    2015-01-01

    mapping of life as an ethnic minority in the city. It revolves around three issues. First, it focuses on the narrators’ experiences of exclusions and blockages in everyday life. This is followed by a focus on urban belonging emphasizing its differential character. Finally, the ambiguity of experiences...

  2. Confronting Ambiguity in Science

    Science.gov (United States)

    Emery, Katherine; Harlow, Danielle; Whitmer, Ali; Gaines, Steven

    2015-01-01

    People are regularly confronted with environmental and science-related issues presented to them in newspapers, on television, or even in their own doctor's office. Often the information they use to inform their decisions on matters of science may be ambiguous and contradictory. This article presents an activity that investigates how students deal…

  3. Semantic ambiguity processing in sentence context: Evidence from event-related fMRI

    NARCIS (Netherlands)

    Zempleni, Monika-Zita; Renken, Remco; Hoeks, John C. J.; Hoogduin, Johannes M.; Stowe, Laurie A.

    2007-01-01

    Lexical semantic ambiguity is the phenomenon when a word has multiple meanings (e.g. 'bank'). The aim of this event-related functional MRI study was to identify those brain areas, which are involved in contextually driven ambiguity resolution. Ambiguous words were selected which have a most

  4. Right-sided representational neglect after left brain damage in a case without visuospatial working memory deficits.

    Science.gov (United States)

    van Dijck, Jean-Philippe; Gevers, Wim; Lafosse, Christophe; Fias, Wim

    2013-10-01

    Brain damaged patients suffering from representational neglect (RN) fail to report, orient to, or verbally describe contra-lesional elements of imagined environments or objects. So far this disorder has only been reported after right brain damage, leading to the idea that only the right hemisphere is involved in this deficit. A widely accepted account attributes RN to a lateralized impairment in the visuospatial component of working memory. So far, however, this hypothesis has not been tested in detail. In the present paper, we describe, for the first time, the case of a left brain damaged patient suffering from right-sided RN while imagining both known and new environments and objects. An in-depth evaluation of her visuospatial working memory abilities, with special focus on the presence of a lateralized deficit, did not reveal any abnormality. In sharp contrast, her ability to memorize visual information was severely compromised. The implications of these results are discussed in the light of recent insights in the neglect syndrome. Copyright © 2013 Elsevier Ltd. All rights reserved.

  5. Ambiguity aversion is not universal

    NARCIS (Netherlands)

    Kocher, M.G.; Lahno, Amrei; Trautmann, Stefan

    Assuming universal ambiguity aversion, an extensive theoretical literature studies how ambiguity can account for market anomalies from the perspective of expected utility-based theories. We provide a systematic experimental assessment of ambiguity attitudes in different likelihood ranges, and in the

  6. From "Where" to "What": Distributed Representations of Brand Associations in the Human Brain.

    Science.gov (United States)

    Chen, Yu-Ping; Nelson, Leif D; Hsu, Ming

    2015-08-01

    Considerable attention has been given to the notion that there exists a set of human-like characteristics associated with brands, referred to as brand personality. Here we combine newly available machine learning techniques with functional neuroimaging data to characterize the set of processes that give rise to these associations. We show that brand personality traits can be captured by the weighted activity across a widely distributed set of brain regions previously implicated in reasoning, imagery, and affective processing. That is, as opposed to being constructed via reflective processes, brand personality traits appear to exist a priori inside the minds of consumers, such that we were able to predict what brand a person is thinking about based solely on the relationship between brand personality associations and brain activity. These findings represent an important advance in the application of neuroscientific methods to consumer research, moving from work focused on cataloguing brain regions associated with marketing stimuli to testing and refining mental constructs central to theories of consumer behavior.

  7. Semantic Ambiguity: Do Multiple Meanings Inhibit or Facilitate Word Recognition?

    Science.gov (United States)

    Haro, Juan; Ferré, Pilar

    2018-06-01

    It is not clear whether multiple unrelated meanings inhibit or facilitate word recognition. Some studies have found a disadvantage for words having multiple meanings with respect to unambiguous words in lexical decision tasks (LDT), whereas several others have shown a facilitation for such words. In the present study, we argue that these inconsistent findings may be due to the approach employed to select ambiguous words across studies. To address this issue, we conducted three LDT experiments in which we varied the measure used to classify ambiguous and unambiguous words. The results suggest that multiple unrelated meanings facilitate word recognition. In addition, we observed that the approach employed to select ambiguous words may affect the pattern of experimental results. This evidence has relevant implications for theoretical accounts of ambiguous words processing and representation.

  8. The development of hand-centred visual representations in the primate brain: a computer modelling study using natural visual scenes.

    Directory of Open Access Journals (Sweden)

    Juan Manuel Galeazzi

    2015-12-01

    Full Text Available Neurons that respond to visual targets in a hand-centred frame of reference have been found within various areas of the primate brain. We investigate how hand-centred visual representations may develop in a neural network model of the primate visual system called VisNet, when the model is trained on images of the hand seen against natural visual scenes. The simulations show how such neurons may develop through a biologically plausible process of unsupervised competitive learning and self-organisation. In an advance on our previous work, the visual scenes consisted of multiple targets presented simultaneously with respect to the hand. Three experiments are presented. First, VisNet was trained with computerized images consisting of a realistic image of a hand and and a variety of natural objects, presented in different textured backgrounds during training. The network was then tested with just one textured object near the hand in order to verify if the output cells were capable of building hand-centered representations with a single localised receptive field. We explain the underlying principles of the statistical decoupling that allows the output cells of the network to develop single localised receptive fields even when the network is trained with multiple objects. In a second simulation we examined how some of the cells with hand-centred receptive fields decreased their shape selectivity and started responding to a localised region of hand-centred space as the number of objects presented in overlapping locations during training increases. Lastly, we explored the same learning principles training the network with natural visual scenes collected by volunteers. These results provide an important step in showing how single, localised, hand-centered receptive fields could emerge under more ecologically realistic visual training conditions.

  9. Translation Ambiguity but Not Word Class Predicts Translation Performance

    Science.gov (United States)

    Prior, Anat; Kroll, Judith F.; Macwhinney, Brian

    2013-01-01

    We investigated the influence of word class and translation ambiguity on cross-linguistic representation and processing. Bilingual speakers of English and Spanish performed translation production and translation recognition tasks on nouns and verbs in both languages. Words either had a single translation or more than one translation. Translation…

  10. Oscillatory neural representations in the sensory thalamus predict neuropathic pain relief by deep brain stimulation.

    Science.gov (United States)

    Huang, Yongzhi; Green, Alexander L; Hyam, Jonathan; Fitzgerald, James; Aziz, Tipu Z; Wang, Shouyan

    2018-01-01

    Understanding the function of sensory thalamic neural activity is essential for developing and improving interventions for neuropathic pain. However, there is a lack of investigation of the relationship between sensory thalamic oscillations and pain relief in patients with neuropathic pain. This study aims to identify the oscillatory neural characteristics correlated with pain relief induced by deep brain stimulation (DBS), and develop a quantitative model to predict pain relief by integrating characteristic measures of the neural oscillations. Measures of sensory thalamic local field potentials (LFPs) in thirteen patients with neuropathic pain were screened in three dimensional feature space according to the rhythm, balancing, and coupling neural behaviours, and correlated with pain relief. An integrated approach based on principal component analysis (PCA) and multiple regression analysis is proposed to integrate the multiple measures and provide a predictive model. This study reveals distinct thalamic rhythms of theta, alpha, high beta and high gamma oscillations correlating with pain relief. The balancing and coupling measures between these neural oscillations were also significantly correlated with pain relief. The study enriches the series research on the function of thalamic neural oscillations in neuropathic pain and relief, and provides a quantitative approach for predicting pain relief by DBS using thalamic neural oscillations. Copyright © 2017 Elsevier Inc. All rights reserved.

  11. Brain activity underlying negative self- and other-perception in adolescents: The role of attachment-derived self-representations.

    Science.gov (United States)

    Debbané, Martin; Badoud, Deborah; Sander, David; Eliez, Stephan; Luyten, Patrick; Vrtička, Pascal

    2017-06-01

    One of teenagers' key developmental tasks is to engage in new and meaningful relationships with peers and adults outside the family context. Attachment-derived expectations about the self and others in terms of internal attachment working models have the potential to shape such social reorientation processes critically and thereby influence adolescents' social-emotional development and social integration. Because the neural underpinnings of this developmental task remain largely unknown, we sought to investigate them by functional magnetic resonance imaging. We asked n = 44 adolescents (ages 12.01-18.84 years) to evaluate positive and negative adjectives regarding either themselves or a close other during an adapted version of the well-established self-other trait-evaluation task. As measures of attachment, we obtained scores reflecting participants' positive versus negative attachment-derived self- and other-models by means of the Relationship Questionnaire. We controlled for possible confounding factors by also obtaining scores reflecting internalizing/externalizing problems, schizotypy, and borderline symptomatology. Our results revealed that participants with a more negative attachment-derived self-model showed increased brain activity during positive and negative adjective evaluation regarding the self, but decreased brain activity during negative adjective evaluation regarding a close other, in bilateral amygdala/parahippocampus, bilateral anterior temporal pole/anterior superior temporal gyrus, and left dorsolateral prefrontal cortex. These findings suggest that a low positivity of the self-concept characteristic for the attachment anxiety dimension may influence neural information processing, but in opposite directions when it comes to self- versus (close) other-representations. We discuss our results in the framework of attachment theory and regarding their implications especially for adolescent social-emotional development and social integration.

  12. An ambiguous relationship

    DEFF Research Database (Denmark)

    Søndergaard Larsen, Lene; Hedegaard Larsen, Birte; Birkelund, Regner

    was sometimes depressing and troublesome. Really understanding and caring for fellow patients was painful. Conclusion: The patients’ interaction is characterized as ambiguous, because interaction between the patients holds both resources and strains. The patient as a care provider may cause curiosity among......Background: The significance of social interaction is commonly discussed and intensively studied as a substantial concept in the nursing profession. Social research conducted in hospital settings has prioritised to examine interaction between patients and doctors, patients and nurses and patients....... Too much information from fellow patients might rock patients’ confidence and hope for own recovery 3) a care provider; the patients’ community was characterized by compassion where they either received care from, or provided care to a fellow patient. Interacting with and supporting fellow patients...

  13. An ambiguous relationship

    DEFF Research Database (Denmark)

    Søndergaard Larsen, Lene; Hedegaard Larsen, Birte; Birkelund, Regner

    2013-01-01

    to qualitative data analysis. Results:  The qualitative meta-synthesis resulted in the heading An Ambiguous Relationship under which three core categories illustrate the hospitalized patients’ different interaction roles. The core categories were as follows: (i) the fellow patient experienced as an enforced......Aim:  The aim of this study was to provide a clear view of the existing knowledge regarding patients’ significance to fellow patients during hospitalization. Method:  Sandelowski and Barroso’s approach to qualitative meta-synthesis was selected and systematically used for collecting and assessing...... findings from qualitative studies. Data consisted of seven qualitative studies published as one book, four scientific articles and two doctoral theses from Scotland, UK, Norway and Denmark. The analysis and synthesis were conducted with inspiration from both Sandelowski and Barroso and Ian Dey’s approach...

  14. Ambiguity aversion in rhesus macaques

    Directory of Open Access Journals (Sweden)

    Benjamin eHayden

    2010-09-01

    Full Text Available People generally prefer risky options, which have fully specified outcome probabilities, to ambiguous options, which have unspecified probabilities. This preference, formalized in economics, is strong enough that people will reliably prefer a risky option to an ambiguous option with a greater expected value. Explanations for ambiguity aversion often invoke uniquely human faculties like language, self-justification, or a desire to avoid public embarrassment. Challenging these ideas, here we demonstrate that a preference for unambiguous options is shared with rhesus macaques. We trained four monkeys to choose between pairs of options that both offered explicitly cued probabilities of large and small juice outcomes. We then introduced occasional trials where one of the options was obscured and examined their resulting preferences; we ran humans in a parallel experiment on a nearly identical task. We found that monkeys reliably preferred risky options to ambiguous ones, even when this bias was costly, closely matching the behavior of humans in the analogous task. Notably, ambiguity aversion varied parametrically with the extent of ambiguity. As expected, ambiguity aversion gradually declined as monkeys learned the underlying probability distribution of rewards. These data indicate that ambiguity aversion reflects fundamental cognitive biases shared with other animals rather than uniquely human factors guiding decisions.

  15. Eliminating ambiguity in digital signals

    Science.gov (United States)

    Weber, W. J., III

    1979-01-01

    Multiamplitude minimum shift keying (mamsk) transmission system, method of differential encoding overcomes problem of ambiguity associated with advanced digital-transmission techniques with little or no penalty in transmission rate, error rate, or system complexity. Principle of method states, if signal points are properly encoded and decoded, bits are detected correctly, regardless of phase ambiguities.

  16. The Ethics of Strategic Ambiguity.

    Science.gov (United States)

    Paul, Jim; Strbiak, Christy A.

    1997-01-01

    Examines the concept of strategic ambiguity in communication, and addresses the ethics of strategic ambiguity from an intrapersonal perspective that considers the congruity of communicators' espoused-ethics, ethics-in-use, and behavior, where ethical judgements are based on the congruity between espoused-ethics and actual behavior. Poses questions…

  17. Reactive agents and perceptual ambiguity

    NARCIS (Netherlands)

    Dartel, M. van; Sprinkhuizen-Kuyper, I.G.; Postma, E.O.; Herik, H.J. van den

    2005-01-01

    Reactive agents are generally believed to be incapable of coping with perceptual ambiguity (i.e., identical sensory states that require different responses). However, a recent finding suggests that reactive agents can cope with perceptual ambiguity in a simple model (Nolfi, 2002). This paper

  18. De morseir syndrome presenting as ambiguous genitalia

    Directory of Open Access Journals (Sweden)

    Anubhav Thukral

    2012-01-01

    Full Text Available Background: A 10-year-old boy presented with genital ambiguity, poor linear growth, and delayed milestones. The aim and to highlight that although rare but congenital, hypogonadotropic hypogonadism may rarely present as ambiguity. Materials and Methods: The patient was found to have bilateral cryptorchidism with proximal penile hypospadias, microphallus with a proportionate dwarfism with mildly delayed bone age, and karyotype 46XY. Euthyroid with normal steroid axis, growth hormone insufficient as suggested by auxology, low IGF1, and poor response to clonidine stimulation. MRI brain shows hypoplastic corpus callosum, hypoplastic anterior pituitary, and ectopic posterior pituitary bright spot. Results: The patient underwent laparoscopic removal of right intrabdominal testis and orchidoplexy was performed on the left one. Testicular biopsy revealed no malignancy and growth hormone replacement was initiated. The patient awaits definitive repair of hypospadias. Conclusion: As a provisional diagnosis of combined growth hormone and gonadotropin deficiency, most probable diagnosis is septo-optic dysplasia or de moseir syndrome leading to genital ambiguity.

  19. What is dorso-lateral in the subthalamic Nucleus (STN)?--a topographic and anatomical consideration on the ambiguous description of today's primary target for deep brain stimulation (DBS) surgery.

    Science.gov (United States)

    Coenen, Volker A; Prescher, Andreas; Schmidt, Thorsten; Picozzi, Piero; Gielen, Frans L H

    2008-11-01

    The most frequently used target for DBS in advanced Parkinson Disease (PD) is the sensorimotor subthalamic nucleus (STN), anatomically referred to as dorso-lateral STN [3]. Ambiguities arise, regarding the true meaning of this description in the STN. Does "dorsal" indicate posterior or superior? At its best, this definition assigns two directions in space to a three-dimensional structure. This paper evaluates the ambiguity and describes the sensorimotor part of the STN in stereotactic space.

  20. Sampling experience reverses preferences for ambiguity

    NARCIS (Netherlands)

    Ert, E.; Trautmann, S.T.

    People often need to choose between alternatives with known probabilities (risk) and alternatives with unknown probabilities (ambiguity). Such decisions are characterized by attitudes towards ambiguity, which are distinct from risk attitudes. Most studies of ambiguity attitudes have focused on the

  1. Quantization ambiguity, ergodicity and semiclassics

    International Nuclear Information System (INIS)

    Kaplan, Lev

    2002-01-01

    It is well known that almost all eigenstates of a classically ergodic system are individually ergodic on coarse-grained scales. This has important implications for the quantization ambiguity in ergodic systems: the difference between alternative quantizations is suppressed compared with the O( h-bar 2 ) ambiguity in the integrable or regular case. For two-dimensional ergodic systems in the high-energy regime, individual eigenstates are independent of the choice of quantization procedure, in contrast with the regular case, where even the ordering of eigenlevels is ambiguous. Surprisingly, semiclassical methods are shown to be much more precise in any dimension for chaotic than for integrable systems

  2. Alcohol reduces aversion to ambiguity

    Directory of Open Access Journals (Sweden)

    Tadeusz eTyszka

    2015-01-01

    Full Text Available Several years ago, Cohen, Dearnaley, and Hansel [1] demonstrated that under the influence of alcohol drivers became more risk prone, although their risk perception remained unchanged. Research shows that ambiguity aversion is to some extent positively correlated with risk aversion, though not very highly [2]. The question addressed by the present research is whether alcohol reduces ambiguity aversion. Our research was conducted in a natural setting (a restaurant bar, where customers with differing levels of alcohol intoxication were offered a choice between a risky and an ambiguous lottery. We found that alcohol reduced ambiguity aversion and that the effect occurred in men but not women. We interpret these findings in terms of the risk-as-value hypothesis, according to which, people in Western culture tend to value risk, and suggest that alcohol consumption triggers adherence to socially and culturally valued patterns of conduct different for men and women.

  3. Alcohol reduces aversion to ambiguity.

    Science.gov (United States)

    Tyszka, Tadeusz; Macko, Anna; Stańczak, Maciej

    2014-01-01

    Several years ago, Cohen et al. (1958) demonstrated that under the influence of alcohol drivers became more risk prone, although their risk perception remained unchanged. Research shows that ambiguity aversion is to some extent positively correlated with risk aversion, though not very highly (Camerer and Weber, 1992). The question addressed by the present research is whether alcohol reduces ambiguity aversion. Our research was conducted in a natural setting (a restaurant bar), where customers with differing levels of alcohol intoxication were offered a choice between a risky and an ambiguous lottery. We found that alcohol reduced ambiguity aversion and that the effect occurred in men but not women. We interpret these findings in terms of the risk-as-value hypothesis, according to which, people in Western culture tend to value risk, and suggest that alcohol consumption triggers adherence to socially and culturally valued patterns of conduct different for men and women.

  4. Mapping cortical hand motor representation using TMS: A method to assess brain plasticity and a surrogate marker for recovery of function after stroke?

    Science.gov (United States)

    Lüdemann-Podubecká, Jitka; Nowak, Dennis Alexander

    2016-10-01

    Stroke is associated with reorganization within motor areas of both hemispheres. Mapping the cortical hand motor representation using transcranial magnetic stimulation may help to understand the relationship between motor cortex reorganization and motor recovery of the affected hand after stroke. A standardized review of the pertinent literature was performed. We identified 20 trials, which analyzed the relationship between the extent and/or location of cortical hand motor representation using transcranial magnetic stimulation and motor function and recovery of the affected hand. Several correlations were found between cortical reorganization and measures of hand motor impairment and recovery. A better understanding of the relationships between the extent and location of cortical hand motor representation and the motor impairment and motor recovery of the affected hand after stroke may contribute to a targeted use of non-invasive brain stimulation protocols. In the future motor mapping may help to guide brain stimulation techniques to the most effective motor area in an affected individual. Copyright © 2016 Elsevier Ltd. All rights reserved.

  5. Audiovisual Capture with Ambiguous Audiovisual Stimuli

    Directory of Open Access Journals (Sweden)

    Jean-Michel Hupé

    2011-10-01

    Full Text Available Audiovisual capture happens when information across modalities get fused into a coherent percept. Ambiguous multi-modal stimuli have the potential to be powerful tools to observe such effects. We used such stimuli made of temporally synchronized and spatially co-localized visual flashes and auditory tones. The flashes produced bistable apparent motion and the tones produced ambiguous streaming. We measured strong interferences between perceptual decisions in each modality, a case of audiovisual capture. However, does this mean that audiovisual capture occurs before bistable decision? We argue that this is not the case, as the interference had a slow temporal dynamics and was modulated by audiovisual congruence, suggestive of high-level factors such as attention or intention. We propose a framework to integrate bistability and audiovisual capture, which distinguishes between “what” competes and “how” it competes (Hupé et al., 2008. The audiovisual interactions may be the result of contextual influences on neural representations (“what” competes, quite independent from the causal mechanisms of perceptual switches (“how” it competes. This framework predicts that audiovisual capture can bias bistability especially if modalities are congruent (Sato et al., 2007, but that is fundamentally distinct in nature from the bistable competition mechanism.

  6. Human Perception of Ambiguous Inertial Motion Cues

    Science.gov (United States)

    Zhang, Guan-Lu

    2010-01-01

    Human daily activities on Earth involve motions that elicit both tilt and translation components of the head (i.e. gazing and locomotion). With otolith cues alone, tilt and translation can be ambiguous since both motions can potentially displace the otolithic membrane by the same magnitude and direction. Transitions between gravity environments (i.e. Earth, microgravity and lunar) have demonstrated to alter the functions of the vestibular system and exacerbate the ambiguity between tilt and translational motion cues. Symptoms of motion sickness and spatial disorientation can impair human performances during critical mission phases. Specifically, Space Shuttle landing records show that particular cases of tilt-translation illusions have impaired the performance of seasoned commanders. This sensorimotor condition is one of many operational risks that may have dire implications on future human space exploration missions. The neural strategy with which the human central nervous system distinguishes ambiguous inertial motion cues remains the subject of intense research. A prevailing theory in the neuroscience field proposes that the human brain is able to formulate a neural internal model of ambiguous motion cues such that tilt and translation components can be perceptually decomposed in order to elicit the appropriate bodily response. The present work uses this theory, known as the GIF resolution hypothesis, as the framework for experimental hypothesis. Specifically, two novel motion paradigms are employed to validate the neural capacity of ambiguous inertial motion decomposition in ground-based human subjects. The experimental setup involves the Tilt-Translation Sled at Neuroscience Laboratory of NASA JSC. This two degree-of-freedom motion system is able to tilt subjects in the pitch plane and translate the subject along the fore-aft axis. Perception data will be gathered through subject verbal reports. Preliminary analysis of perceptual data does not indicate that

  7. Hierarchical Morphological Structure and Ambiguity

    DEFF Research Database (Denmark)

    Vikner, Carl; Vikner, Sten

    2008-01-01

    English has a number of adjectives of the type unXable, adjectives that contain the prefix un- and the adjectivising suffix -able, e.g. unlockable or undoable. Many of these adjectives are ambiguous. If a door is unlockable, it may either mean that it cannot be locked (it is not lockable), as exp......English has a number of adjectives of the type unXable, adjectives that contain the prefix un- and the adjectivising suffix -able, e.g. unlockable or undoable. Many of these adjectives are ambiguous. If a door is unlockable, it may either mean that it cannot be locked (it is not lockable...

  8. Ambiguous Science and the Visual Representation of the Real

    Science.gov (United States)

    Newbold, Curtis Robert

    2012-01-01

    The emergence of visual media as prominent and even expected forms of communication in nearly all disciplines, including those scientific, has raised new questions about how the art and science of communication epistemologically affect the interpretation of scientific phenomena. In this dissertation I explore how the influence of aesthetics in…

  9. Symbol in View of Ambiguity

    Directory of Open Access Journals (Sweden)

    Mohamad reza Yousefi

    2013-11-01

    Full Text Available Abstract Symbol from the perspective of rhetorical word, is phrase or sentence that apparent meaning, also inspires to reader a wide range of semantic.Since exploring the complex social and political ideas in the most mysticalway and indirectreflectionsocial and political thoughts symbolically is easier, so the symbol and symbolism especially in Persian literatureespeciallyin the realm of Persian poetry, has a special appearance.In addition to the factors mentioned in the contemporary literature, according familiar in literature and the emergence of particular schools interest toambiguoussymbolization has spreadfurther, especially the symbol has all the features of art ambiguity in the poem and it isone the major factors causing uncertainty.Thus, the precise definitions and symbols of contemporary poetry could be dominant in the unwinding ambiguous symbol detection of cryptic allusions and metaphors that matches the cursor symbol to help readers.  In the literature, especially language poetry, the inability of language toreflecting obscure mystical ideas, avoid to directexpression of political and social concerns of the reader in the course of participate to creation ambiguous literary works is the main motivation towards symbol and symbolization.According widespread use of symbol and its different of species can be viewed from different perspectives.The creation of ambiguity is the main purposes of using symbols (especially in poetry, so many poets have tried to achieve this goal have to formation of similar symbols and the explanation and resolution of this issue can open new window for understanding the poetry in front of an audience.  In this paper examines the ambiguity of symbols in terms of its precise boundaries are reviewed. Ambiguity is one of the important processes and also is the key Iranian poetry its means is today poetry. In such poetry ambiguity is a need to explore the new world from a different perspective, or explore this

  10. Spectral Ambiguity of Allan Variance

    Science.gov (United States)

    Greenhall, C. A.

    1996-01-01

    We study the extent to which knowledge of Allan variance and other finite-difference variances determines the spectrum of a random process. The variance of first differences is known to determine the spectrum. We show that, in general, the Allan variance does not. A complete description of the ambiguity is given.

  11. Origin of the Gribov ambiguity

    International Nuclear Information System (INIS)

    Takahashi, Y.; Kobayashi, M.

    1978-01-01

    It is pointed out that the Gribov ambiguity for the non-abelian transverse gauge field has the same origin as the Johnson-Sudarshan problem for the spin-3/2 field as well as the propagation problem discovered by Velo and Zwanziger. (Auth.)

  12. Bank risk, bailouts and ambiguity

    NARCIS (Netherlands)

    Nijskens, R.G.M.

    2012-01-01

    The theoretical analysis in the second part investigates the effect of liquidity assistance and bailouts on bank risk taking and liquidity choice. Furthermore, it explores the possibilities for central banks to create ambiguity about liquidity assistance, thereby influencing bank choices. The

  13. Crichton's phase-shift ambiguity

    NARCIS (Netherlands)

    Atkinson, D.; Johnson, P.W.; Mehta, N.; Roo, M. de

    1973-01-01

    A re-examination of the SPD phase-shift ambiguity is made with a view to understanding certain singular features of the elastic unitarity constraint. An explicit solution of Crichton's equations is presented, and certain features of this solution are displayed graphically. In particular, it is shown

  14. Theory-Based Evaluation Meets Ambiguity

    DEFF Research Database (Denmark)

    Dahler-Larsen, Peter

    2017-01-01

    As theory-based evaluation (TBE) engages in situations where multiple stakeholders help develop complex program theory about dynamic phenomena in politically contested settings, it becomes difficult to develop and use program theory without ambiguity. The purpose of this article is to explore...... ambiguity as a fruitful perspective that helps TBE face current challenges. Literatures in organization theory and political theory are consulted in order to cultivate the concept of ambiguity. Janus variables (which work in two ways) and other ambiguous aspects of program theories are classified...... and exemplified. Stances towards ambiguity are considered, as are concrete steps that TBE evaluators can take to identify and deal with ambiguity in TBE....

  15. Searching for the best model: ambiguity of inverse solutions and application to fetal magnetoencephalography

    International Nuclear Information System (INIS)

    Vrba, J; Robinson, S E; McCubbin, J; Lowery, C L; Eswaran, H; Murphy, P; Preissl, H

    2007-01-01

    Fetal brain signals produce weak magnetic fields at the maternal abdominal surface. In the presence of much stronger interference these weak fetal fields are often nearly indistinguishable from noise. Our initial objective was to validate these weak fetal brain fields by demonstrating that they agree with the electromagnetic model of the fetal brain. The fetal brain model is often not known and we have attempted to fit the data to not only the brain source position, orientation and magnitude, but also to the brain model position. Simulation tests of this extended model search on fetal MEG recordings using dipole fit and beamformers revealed a region of ambiguity. The region of ambiguity consists of a family of models which are not distinguishable in the presence of noise, and which exhibit large and comparable SNR when beamformers are used. Unlike the uncertainty of a dipole fit with known model plus noise, this extended ambiguity region yields nearly identical forward solutions, and is only weakly dependent on noise. The ambiguity region is located in a plane defined by the source position, orientation, and the true model centre, and will have a diameter approximately 0.67 of the modelled fetal head diameter. Existence of the ambiguity region allows us to only state that the fetal brain fields do not contradict the electromagnetic model; we can associate them with a family of models belonging to the ambiguity region, but not with any specific model. In addition to providing a level of confidence in the fetal brain signals, the ambiguity region knowledge in combination with beamformers allows detection of undistorted temporal waveforms with improved signal-to-noise ratio, even though the source position cannot be uniquely determined

  16. Sensory memory for ambiguous vision.

    Science.gov (United States)

    Pearson, Joel; Brascamp, Jan

    2008-09-01

    In recent years the overlap between visual perception and memory has shed light on our understanding of both. When ambiguous images that normally cause perception to waver unpredictably are presented briefly with intervening blank periods, perception tends to freeze, locking into one interpretation. This indicates that there is a form of memory storage across the blank interval. This memory trace codes low-level characteristics of the stored stimulus. Although a trace is evident after a single perceptual instance, the trace builds over many separate stimulus presentations, indicating a flexible, variable-length time-course. This memory shares important characteristics with priming by non-ambiguous stimuli. Computational models now provide a framework to interpret many empirical observations.

  17. Productive Ambiguity in the Learning of Mathematics

    Science.gov (United States)

    Foster, Colin

    2011-01-01

    In this paper I take a positive view of ambiguity in the learning of mathematics. Following Grosholz (2007), I argue that it is not only the arts which exploit ambiguity for creative ends but science and mathematics too. By enabling the juxtaposition of multiple conflicting frames of reference, ambiguity allows novel connections to be made. I…

  18. Generative Learning: Adults Learning within Ambiguity

    Science.gov (United States)

    Nicolaides, Aliki

    2015-01-01

    This study explored the extent to which ambiguity can serve as a catalyst for adult learning. The purpose of this study is to understand learning that is generated when encountering ambiguity agitated by the complexity of liquid modernity. "Ambiguity," in this study, describes an encounter with an appearance of reality that is at first…

  19. The Inhibitory Mechanism in Learning Ambiguous Words in a Second Language.

    Science.gov (United States)

    Lu, Yao; Wu, Junjie; Dunlap, Susan; Chen, Baoguo

    2017-01-01

    Ambiguous words are hard to learn, yet little is known about what causes this difficulty. The current study aimed to investigate the relationship between the representations of new and prior meanings of ambiguous words in second language (L2) learning, and to explore the function of inhibitory control on L2 ambiguous word learning at the initial stage of learning. During a 4-day learning phase, Chinese-English bilinguals learned 30 novel English words for 30 min per day using bilingual flashcards. Half of the words to be learned were unambiguous (had one meaning) and half were ambiguous (had two semantically unrelated meanings learned in sequence). Inhibitory control was introduced as a subject variable measured by a Stroop task. The semantic representations established for the studied items were probed using a cross-language semantic relatedness judgment task, in which the learned English words served as the prime, and the targets were either semantically related or unrelated to the prime. Results showed that response latencies for the second meaning of ambiguous words were slower than for the first meaning and for unambiguous words, and that performance on only the second meaning of ambiguous words was predicted by inhibitory control ability. These results suggest that, at the initial stage of L2 ambiguous word learning, the representation of the second meaning is weak, probably interfered with by the representation of the prior learned meaning. Moreover, inhibitory control may modulate learning of the new meanings, such that individuals with better inhibitory control may more effectively suppress interference from the first meaning, and thus learn the new meaning more quickly.

  20. The Inhibitory Mechanism in Learning Ambiguous Words in a Second Language

    Directory of Open Access Journals (Sweden)

    Baoguo Chen

    2017-04-01

    Full Text Available Ambiguous words are hard to learn, yet little is known about what causes this difficulty. The current study aimed to investigate the relationship between the representations of new and prior meanings of ambiguous words in second language (L2 learning, and to explore the function of inhibitory control on L2 ambiguous word learning at the initial stage of learning. During a 4-day learning phase, Chinese–English bilinguals learned 30 novel English words for 30 min per day using bilingual flashcards. Half of the words to be learned were unambiguous (had one meaning and half were ambiguous (had two semantically unrelated meanings learned in sequence. Inhibitory control was introduced as a subject variable measured by a Stroop task. The semantic representations established for the studied items were probed using a cross-language semantic relatedness judgment task, in which the learned English words served as the prime, and the targets were either semantically related or unrelated to the prime. Results showed that response latencies for the second meaning of ambiguous words were slower than for the first meaning and for unambiguous words, and that performance on only the second meaning of ambiguous words was predicted by inhibitory control ability. These results suggest that, at the initial stage of L2 ambiguous word learning, the representation of the second meaning is weak, probably interfered with by the representation of the prior learned meaning. Moreover, inhibitory control may modulate learning of the new meanings, such that individuals with better inhibitory control may more effectively suppress interference from the first meaning, and thus learn the new meaning more quickly.

  1. Context sensitivity and ambiguity in component-based systems design

    Energy Technology Data Exchange (ETDEWEB)

    Bespalko, S.J.; Sindt, A.

    1997-10-01

    Designers of components-based, real-time systems need to guarantee to correctness of soft-ware and its output. Complexity of a system, and thus the propensity for error, is best characterized by the number of states a component can encounter. In many cases, large numbers of states arise where the processing is highly dependent on context. In these cases, states are often missed, leading to errors. The following are proposals for compactly specifying system states which allow the factoring of complex components into a control module and a semantic processing module. Further, the need for methods that allow for the explicit representation of ambiguity and uncertainty in the design of components is discussed. Presented herein are examples of real-world problems which are highly context-sensitive or are inherently ambiguous.

  2. From “Where” to “What”: Distributed Representations of Brand Associations in the Human Brain

    Science.gov (United States)

    Chen, Yu-Ping; Nelson, Leif D.; Hsu, Ming

    2015-01-01

    Considerable attention has been given to the notion that there exists a set of human-like characteristics associated with brands, referred to as brand personality. Here we combine newly available machine learning techniques with functional neuroimaging data to characterize the set of processes that give rise to these associations. We show that brand personality traits can be captured by the weighted activity across a widely distributed set of brain regions previously implicated in reasoning, imagery, and affective processing. That is, as opposed to being constructed via reflective processes, brand personality traits appear to exist a priori inside the minds of consumers, such that we were able to predict what brand a person is thinking about based solely on the relationship between brand personality associations and brain activity. These findings represent an important advance in the application of neuroscientific methods to consumer research, moving from work focused on cataloguing brain regions associated with marketing stimuli to testing and refining mental constructs central to theories of consumer behavior. PMID:27065490

  3. Numbers and brains.

    Science.gov (United States)

    Gallistel, C R

    2017-12-01

    The representation of discrete and continuous quantities appears to be ancient and pervasive in animal brains. Because numbers are the natural carriers of these representations, we may discover that in brains, it's numbers all the way down.

  4. The ambiguous challenge of intranets

    DEFF Research Database (Denmark)

    Thommesen, Jacob

    2003-01-01

    increases with tendencies to cooperate and communicate across organisational boundaries, mainly as a reaction to developments in markets and industrial knowledge base, but also due to the potential provided by computer network. In the third chapter I identify some characteristics of two fundamental intranet...... media, email and the web, partly in the perspective of media richness theory, partly compared with philosophical discussions of classical media. The fourth chapter presents an intranet in a global company, in which problems and challenges related to ambiguity have proven significant....

  5. Rocking or rolling--perception of ambiguous motion after returning from space.

    Directory of Open Access Journals (Sweden)

    Gilles Clément

    Full Text Available The central nervous system must resolve the ambiguity of inertial motion sensory cues in order to derive an accurate representation of spatial orientation. Adaptive changes during spaceflight in how the brain integrates vestibular cues with other sensory information can lead to impaired movement coordination, vertigo, spatial disorientation, and perceptual illusions after return to Earth. The purpose of this study was to compare tilt and translation motion perception in astronauts before and after returning from spaceflight. We hypothesized that these stimuli would be the most ambiguous in the low-frequency range (i.e., at about 0.3 Hz where the linear acceleration can be interpreted either as a translation or as a tilt relative to gravity. Verbal reports were obtained in eleven astronauts tested using a motion-based tilt-translation device and a variable radius centrifuge before and after flying for two weeks on board the Space Shuttle. Consistent with previous studies, roll tilt perception was overestimated shortly after spaceflight and then recovered with 1-2 days. During dynamic linear acceleration (0.15-0.6 Hz, ±1.7 m/s2 perception of translation was also overestimated immediately after flight. Recovery to baseline was observed after 2 days for lateral translation and 8 days for fore-aft translation. These results suggest that there was a shift in the frequency dynamic of tilt-translation motion perception after adaptation to weightlessness. These results have implications for manual control during landing of a space vehicle after exposure to microgravity, as it will be the case for human asteroid and Mars missions.

  6. Perirhinal Cortex Resolves Feature Ambiguity in Configural Object Recognition and Perceptual Oddity Tasks

    Science.gov (United States)

    Bartko, Susan J.; Winters, Boyer D.; Cowell, Rosemary A.; Saksida, Lisa M.; Bussey, Timothy J.

    2007-01-01

    The perirhinal cortex (PRh) has a well-established role in object recognition memory. More recent studies suggest that PRh is also important for two-choice visual discrimination tasks. Specifically, it has been suggested that PRh contains conjunctive representations that help resolve feature ambiguity, which occurs when a task cannot easily be…

  7. Ambiguity effects of rhyme and meter.

    Science.gov (United States)

    Wallot, Sebastian; Menninghaus, Winfried

    2018-04-23

    Previous research has shown that rhyme and meter-although enhancing prosodic processing ease and memorability-also tend to make semantic processing more demanding. Using a set of rhymed and metered proverbs, as well as nonrhymed and nonmetered versions of these proverbs, the present study reveals this hitherto unspecified difficulty of comprehension to be specifically driven by perceived ambiguity. Roman Jakobson was the 1st to propose this hypothesis, in 1960. He suggested that "ambiguity is an intrinsic, inalienable feature" of "parallelistic" diction of which the combination of rhyme and meter is a pronounced example. Our results show that ambiguity indeed explains a substantial portion of the rhyme- and meter-driven difficulty of comprehension. Longer word-reading times differentially reflected ratings for ambiguity and comprehension difficulty. However, the ambiguity effect is not "inalienable." Rather, many rhymed and metered sentences turned out to be low in ambiguity. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

  8. Renormalon ambiguities in NRQCD operator matrix elements

    International Nuclear Information System (INIS)

    Bodwin, G.T.; Chen, Y.

    1999-01-01

    We analyze the renormalon ambiguities that appear in factorization formulas in QCD. Our analysis contains a simple argument that the ambiguities in the short-distance coefficients and operator matrix elements are artifacts of dimensional-regularization factorization schemes and are absent in cutoff schemes. We also present a method for computing the renormalon ambiguities in operator matrix elements and apply it to a computation of the ambiguities in the matrix elements that appear in the NRQCD factorization formulas for the annihilation decays of S-wave quarkonia. Our results, combined with those of Braaten and Chen for the short-distance coefficients, provide an explicit demonstration that the ambiguities cancel in the physical decay rates. In addition, we analyze the renormalon ambiguities in the Gremm-Kapustin relation and in various definitions of the heavy-quark mass. copyright 1999 The American Physical Society

  9. SAR Ambiguity Study for the Cassini Radar

    Science.gov (United States)

    Hensley, Scott; Im, Eastwood; Johnson, William T. K.

    1993-01-01

    The Cassini Radar's synthetic aperture radar (SAR) ambiguity analysis is unique with respect to other spaceborne SAR ambiguity analyses owing to the non-orbiting spacecraft trajectory, asymmetric antenna pattern, and burst mode of data collection. By properly varying the pointing, burst mode timing, and radar parameters along the trajectory this study shows that the signal-to-ambiguity ratio of better than 15 dB can be achieved for all images obtained by the Cassini Radar.

  10. Visual working memory contents bias ambiguous structure from motion perception.

    Directory of Open Access Journals (Sweden)

    Lisa Scocchia

    Full Text Available The way we perceive the visual world depends crucially on the state of the observer. In the present study we show that what we are holding in working memory (WM can bias the way we perceive ambiguous structure from motion stimuli. Holding in memory the percept of an unambiguously rotating sphere influenced the perceived direction of motion of an ambiguously rotating sphere presented shortly thereafter. In particular, we found a systematic difference between congruent dominance periods where the perceived direction of the ambiguous stimulus corresponded to the direction of the unambiguous one and incongruent dominance periods. Congruent dominance periods were more frequent when participants memorized the speed of the unambiguous sphere for delayed discrimination than when they performed an immediate judgment on a change in its speed. The analysis of dominance time-course showed that a sustained tendency to perceive the same direction of motion as the prior stimulus emerged only in the WM condition, whereas in the attention condition perceptual dominance dropped to chance levels at the end of the trial. The results are explained in terms of a direct involvement of early visual areas in the active representation of visual motion in WM.

  11. Space-frequency analysis and reduction of potential field ambiguity

    Directory of Open Access Journals (Sweden)

    A. Rapolla

    1997-06-01

    Full Text Available Ambiguity of depth estimation of magnetic sources via spectral analysis can be reduced representing its field via a set of space-frequency atoms. This is obtained throughout a continuous wavelet transform using a Morlet analyzing wavelet. In the phase-plane representation even a weak contribution related to deep-seated sources is clearly distinguished with respect a more intense effect of a shallow source, also in the presence of a strong noise. Furthermore, a new concept of local power spectrum allows the depth to both the sources to be correctly interpreted. Neither result can be provided by standard Fourier analysis. Another method is proposed to reduce ambiguity by inversion of potential field data lying along the vertical axis. This method allows a depth resolution to gravity or the magnetic methods and below some conditions helps to reduce their inherent ambiguity. Unlike the case of monopoles, inversion of a vertical profile of gravity data above a cubic source gives correct results for the cube side and density.

  12. Effective ambiguity checking in biosequence analysis

    Directory of Open Access Journals (Sweden)

    Giegerich Robert

    2005-06-01

    Full Text Available Abstract Background Ambiguity is a problem in biosequence analysis that arises in various analysis tasks solved via dynamic programming, and in particular, in the modeling of families of RNA secondary structures with stochastic context free grammars. Several types of analysis are invalidated by the presence of ambiguity. As this problem inherits undecidability (as we show here from the namely problem for context free languages, there is no complete algorithmic solution to the problem of ambiguity checking. Results We explain frequently observed sources of ambiguity, and show how to avoid them. We suggest four testing procedures that may help to detect ambiguity when present, including a just-in-time test that permits to work safely with a potentially ambiguous grammar. We introduce, for the special case of stochastic context free grammars and RNA structure modeling, an automated partial procedure for proving non-ambiguity. It is used to demonstrate non-ambiguity for several relevant grammars. Conclusion Our mechanical proof procedure and our testing methods provide a powerful arsenal of methods to ensure non-ambiguity.

  13. Analyzing Ambiguity of Context-Free Grammars

    DEFF Research Database (Denmark)

    Brabrand, Claus; Giegerich, Robert; Møller, Anders

    2010-01-01

    It has been known since 1962 that the ambiguity problem for context-free grammars is undecidable. Ambiguity in context-free grammars is a recurring problem in language design and parser generation, as well as in applications where grammars are used as models of real-world physical structures. We...... observe that there is a simple linguistic characterization of the grammar ambiguity problem, and we show how to exploit this by presenting an ambiguity analysis framework based on conservative language approximations. As a concrete example, we propose a technique based on local regular approximations...

  14. AMBIGUOUS JANUS OF MODERN DEMOCRACY

    Directory of Open Access Journals (Sweden)

    Volodymyr V. Khmil

    2016-06-01

    Full Text Available Purpose. The purpose of the research is to analyze ambiguous concept of  democracy as a phenomenon of political and social formation based on political and instrumental approach. As a result, some deep fundamentals of  human social existence and values as social life basis are blurred. Task. The task of  this investigation is to reveal the concept of democracy in its invariative philosophical  meaning and find the consequences of global social transformations towards social entropy. Methods of investigation. To implement the task an activity approach has been used with further possibility to single out two approaches - politological and philosophical. The focus on democracy from philosophic point of view makes possible to anticipate negative entropic processes that lead  to future ambiguity. Subject matter. Chaotic social processes can result in  ruined family, spiritual, legal and moral formations. Regulatory and legal paradigms are becoming less effective and entail disintegration of spiritual and value constituents of worldview causing necessary conditions for social entropy. Originality and Findings. Possible threats for human freedom that hinder the way to targeted  prospects of mankind have been considered in the paper. Thus, taking into account all positive aspects of democracy, it is simultaneously becoming the tool of continuous differentiation of society into tiny autonomous communities similar to nomadic atomization of society. The concept based on moral substantial existence basis as in “axis time” by K. Jaspers that can prevent social entropy resulting in world anthropologic catastrophes has been grounded in the present research.

  15. Roles of frontal and temporal regions in reinterpreting semantically ambiguous sentences

    Directory of Open Access Journals (Sweden)

    Sylvia eVitello

    2014-07-01

    Full Text Available Semantic ambiguity resolution is an essential and frequent part of speech comprehension because many words map onto multiple meanings (e.g., bark, bank. Neuroimaging research highlights the importance of the left inferior frontal gyrus (LIFG and the left posterior temporal cortex in this process but the roles they serve in ambiguity resolution are uncertain. One possibility is that both regions are engaged in the processes of semantic reinterpretation that follows incorrect interpretation of an ambiguous word. Here we used fMRI to investigate this hypothesis. 20 native British English monolinguals were scanned whilst listening to sentences that contained an ambiguous word. To induce semantic reinterpretation, the disambiguating information was presented after the ambiguous word and delayed until the end of the sentence (e.g., the teacher explained that the BARK was going to be very damp. These sentences were compared to well-matched unambiguous sentences. Supporting the reinterpretation hypothesis, these ambiguous sentences produced more activation in both the LIFG and the left posterior inferior temporal cortex. Importantly, all but one subject showed ambiguity-related peaks within both regions, demonstrating that the group-level results were driven by high inter-subject consistency. Further support came from the finding that activation in both regions was modulated by meaning dominance. Specifically, sentences containing biased ambiguous words, which have one more dominant meaning, produced greater activation than those with balanced ambiguous words, which have two equally frequent meanings. Because the context always supported the less frequent meaning, the biased words require reinterpretation more often than balanced words. This is the first evidence of dominance effects in the spoken modality and provides strong support that frontal and temporal regions support the updating of semantic representations during speech comprehension.

  16. Ambiguity and Volatility : Asset Pricing Implications

    NARCIS (Netherlands)

    Pataracchia, B.

    2011-01-01

    Using a simple dynamic consumption-based asset pricing model, this paper explores the implications of a representative investor with smooth ambiguity averse preferences [Klibano¤, Marinacci and Mukerji, Econometrica (2005)] and provides a comparative analysis of risk aversion and ambiguity aversion.

  17. The Communicative Function of Ambiguity in Language

    Science.gov (United States)

    Piantadosi, Steven T.; Tily, Harry; Gibson, Edward

    2012-01-01

    We present a general information-theoretic argument that all efficient communication systems will be ambiguous, assuming that context is informative about meaning. We also argue that ambiguity allows for greater ease of processing by permitting efficient linguistic units to be re-used. We test predictions of this theory in English, German, and…

  18. Crichton ambiguities with infinitely many partial waves

    International Nuclear Information System (INIS)

    Atkinson, D.; Kok, L.P.; de Roo, M.

    1978-01-01

    We construct families of spinless two-particle unitary cross sections that possess a nontrivial discrete phase-shift ambiguity, with in general an infinite number of nonvanishing partial waves. A numerical investigation reveals that some of the previously known finite Crichton ambiguities are merely special cases of the newly constructed examples

  19. Ambiguity attitudes in decisions for others

    NARCIS (Netherlands)

    König-Kersting, Christian; Trautmann, Stefan

    We probe the pattern of ambiguity aversion for moderate-likelihood gain prospects, and ambiguity seeking for low-likelihood gain prospects, if people make decisions not for themselves but as agents for others. We confirm the pattern both with and without accountability.

  20. Processing subject-object ambiguities in Dutch

    NARCIS (Netherlands)

    Kaan, Edith

    1997-01-01

    Various clause types in Dutch and German are at least temporarily ambiguous with respect to the order of subject and object. A number of previous studies regarding the processing of such subject-object ambiguities have reported a preference for a subject-object interpretation. This order preference

  1. Crichton ambiguities with infinitely many partial waves

    NARCIS (Netherlands)

    Atkinson, D.; Kok, L.P.; de Roo, M.

    We construct families of spin less two-particle unitary cross sections that possess a nontrivial discrete phase-shift ambiguity, with in general an infinite number of nonvanishing partial waves. A numerical investigation reveals that some of the previously known finite Crichton ambiguities are

  2. Acute leukemias of ambiguous lineage.

    Science.gov (United States)

    Béné, Marie C; Porwit, Anna

    2012-02-01

    The 2008 edition of the WHO Classification of Tumors of Haematopoietic and Lymphoid Tissues recognizes a special category called "leukemias of ambiguous lineage." The vast majority of these rare leukemias are classified as mixed phenotype acute leukemia (MPAL), although acute undifferentiated leukemias and natural killer lymphoblastic leukemias are also included. The major immunophenotypic markers used by the WHO 2008 to determine the lineage for these proliferations are myeloperoxidase, CD19, and cytoplasmic CD3. However, extensive immunophenotyping is necessary to confirm that the cells indeed belong to 2 different lineages or coexpress differentiation antigens of more than 1 lineage. Specific subsets of MPAL are defined by chromosomal anomalies such as the t(9;22) Philadelphia chromosome BCR-ABL1 or involvement of the MLL gene on chromosome 11q23. Other MPAL are divided into B/myeloid NOS, T/myeloid NOS, B/T NOS, and B/T/myeloid NOS. MPAL are usually of dire prognosis, respond variably to chemotherapy of acute lymphoblastic or acute myeloblastic type, and benefit most from rapid allogeneic hematopoietic stem cell transplantation.

  3. Emotion and decision-making under uncertainty: Physiological arousal predicts increased gambling during ambiguity but not risk.

    Science.gov (United States)

    FeldmanHall, Oriel; Glimcher, Paul; Baker, Augustus L; Phelps, Elizabeth A

    2016-10-01

    Uncertainty, which is ubiquitous in decision-making, can be fractionated into known probabilities (risk) and unknown probabilities (ambiguity). Although research has illustrated that individuals more often avoid decisions associated with ambiguity compared to risk, it remains unclear why ambiguity is perceived as more aversive. Here we examine the role of arousal in shaping the representation of value and subsequent choice under risky and ambiguous decisions. To investigate the relationship between arousal and decisions of uncertainty, we measure skin conductance response-a quantifiable measure reflecting sympathetic nervous system arousal-during choices to gamble under risk and ambiguity. To quantify the discrete influences of risk and ambiguity sensitivity and the subjective value of each option under consideration, we model fluctuating uncertainty, as well as the amount of money that can be gained by taking the gamble. Results reveal that although arousal tracks the subjective value of a lottery regardless of uncertainty type, arousal differentially contributes to the computation of value-that is, choice-depending on whether the uncertainty is risky or ambiguous: Enhanced arousal adaptively decreases risk-taking only when the lottery is highly risky but increases risk-taking when the probability of winning is ambiguous (even after controlling for subjective value). Together, this suggests that the role of arousal during decisions of uncertainty is modulatory and highly dependent on the context in which the decision is framed. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

  4. An ambiguity in fermionic string perturbation theory

    International Nuclear Information System (INIS)

    Atick, J.J.; Rabin, J.M.

    1988-01-01

    Recent investigation by Verlinde and Verlinde has shown that the fermionic string loop amplitudes change by a total derivative term in the moduli space under a change of basis of the supermoduli. This ambiguity is addressed in the context of the heterotic string theory, and shown to be a consequence of an inherent ambiguity in defining integration over the variables of a Grassmann algebra - in this case the Grassmann-valued coordinates of the supermoduli space. A resolution of this ambiguity in genus-two within this formalism is also presented. (orig.)

  5. Gauge-fixing ambiguity and monopole number

    International Nuclear Information System (INIS)

    Hioki, S.; Miyamura, O.

    1991-01-01

    Gauge-fixing ambiguities of lattice SU(2) QCD are studied in the maximally abelian and unitary gauges. In the former, we find local maxima of a gauge-fixing function which may correspond to Gribov copies. There is a definite anti-correlation between the number of monopoles and the value of the function. Errors of measured quantities coming from the ambiguity are found to be less than inherent dispersion in the ensemble average. No ambiguity is found in the unitary gauges. (orig.)

  6. Analyzing Ambiguity of Context-Free Grammars

    DEFF Research Database (Denmark)

    Brabrand, Claus; Giegerich, Robert; Møller, Anders

    2007-01-01

    It has been known since 1962 that the ambiguity problem for context-free grammars is undecidable. Ambiguity in context-free grammars is a recurring problem in language design and parser generation, as well as in applications where grammars are used as models of real-world physical structures. We...... observe that there is a simple linguistic characterization of the grammar ambiguity problem, and we show how to exploit this to conservatively approximate the problem based on local regular approximations and grammar unfoldings. As an application, we consider grammars that occur in RNA analysis...

  7. Perturbative ambiguities in Coulomb gauge QCD

    International Nuclear Information System (INIS)

    Doust, P.

    1987-01-01

    The naive Coulomb gauge Feynman rules in non-abelian gauge theory give rise to ambiguous integrals, in addition to the usual ultraviolet divergences. Generalizing the work of Cheng and Tsai, these ambiguities are resolved to all orders in perturbation theory, by defining a gauge that interpolates smoothly between the Feynman gauge and the Coulomb gauge. The extra terms V 1 +V 2 of Christ and Lee are identified with certain two-loop ambiguous terms. However, there still seem to be unsolved problems connected with renormalisation. copyright 1987 Academic Press, Inc

  8. Equity Trading under Heterogeneity in Ambiguity

    DEFF Research Database (Denmark)

    Alonso, Irasema; Prado, Mauricio

    -relevant, but hard-to-interpret information: a situation like that during the onset of the recent crisis in financial markets. During this episode, market participants appeared unsure of the values of a variety of assets, trading all but stopped. Ambiguity aversion, it appears to us, offers a tractable way......-participation - a drastic form of trading less - in the ambiguity-ridden market by certain agents (here we have in mind those with higher levels of ambiguity). This endogenous limited participation on the market also has implications for the relative wealth of agents in an economy. The dynamics of the wealth distribution...

  9. Using Distributed Representations to Disambiguate Biomedical and Clinical Concepts

    OpenAIRE

    Tulkens, Stéphan; Šuster, Simon; Daelemans, Walter

    2016-01-01

    In this paper, we report a knowledge-based method for Word Sense Disambiguation in the domains of biomedical and clinical text. We combine word representations created on large corpora with a small number of definitions from the UMLS to create concept representations, which we then compare to representations of the context of ambiguous terms. Using no relational information, we obtain comparable performance to previous approaches on the MSH-WSD dataset, which is a well-known dataset in the bi...

  10. Poetic representation

    DEFF Research Database (Denmark)

    Wulf-Andersen, Trine Østergaard

    2012-01-01

    , and dialogue, of situated participants. The article includes a lengthy example of a poetic representation of one participant’s story, and the author comments on the potentials of ‘doing’ poetic representations as an example of writing in ways that challenges what sometimes goes unasked in participative social...

  11. Ambiguity and violence in adolescent dating relationships.

    Science.gov (United States)

    Draucker, Claire Burke; Martsolf, Donna; Stephenson, Pam Shockey

    2012-08-01

    Little is known about dyadic processes that lead to adolescent dating violence. The purpose of this study was to examine the phenomenon of relationship ambiguity in adolescent dating relationships to better understand how ambiguity contributes to violence and aggression between dating partners. Data were drawn from 88 narratives of young adults who had participated in a study on adolescent dating violence. Interpretive phenomenology was used to produce an in-depth description of the phenomenon of relationship ambiguity. Relationship ambiguity results in differing expectations between partners regarding closeness and intimacy, fidelity, and obligation. These differences lead to conflicts that set the stage for violence and aggression in adolescent dating relationships. A series of recommendations for clinicians working with adolescents are presented. © 2012 Wiley Periodicals, Inc.

  12. Clarity and ambiguity in strategic corporate communication

    DEFF Research Database (Denmark)

    Gulbrandsen, Ib Tunby

    2017-01-01

    as they are decoupled from the strategy itself. Research limitations/implications – As the findings are based on a study of the understanding and practice of corporate communication strategy in one concrete organization, the study points to the need for additional explorations and examinations of ambiguity in strategic...... how they perceived the writing, reading and enactment of their organization’s new corporate communication strategy. Findings – The analysis reveals the presence of both clarity and ambiguity in the employees’ understanding of the strategy. Both in terms of formulation and implementation. For instance...... corporate communication. Originality/value – Despite numerous studies on the presence of ambiguity in strategy making in the neighbouring field of strategic management, the majority of strategic corporate communication literature largely treats ambiguity as something that should be absent. This has caused...

  13. Clarity and ambiguity in strategic corporate communication

    DEFF Research Database (Denmark)

    Gulbrandsen, Ib Tunby

    2018-01-01

    as they are decoupled from the strategy itself. Research limitations/implications – As the findings are based on a study of the understanding and practice of corporate communication strategy in one concrete organization, the study points to the need for additional explorations and examinations of ambiguity in strategic...... how they perceived the writing, reading and enactment of their organization’s new corporate communication strategy. Findings – The analysis reveals the presence of both clarity and ambiguity in the employees’ understanding of the strategy. Both in terms of formulation and implementation. For instance...... corporate communication. Originality/value – Despite numerous studies on the presence of ambiguity in strategy making in the neighbouring field of strategic management, the majority of strategic corporate communication literature largely treats ambiguity as something that should be absent. This has caused...

  14. Risk Management and Insurance Decisions under Ambiguity

    DEFF Research Database (Denmark)

    Martínez-Correa, Jimmy

    I study the impact of ambiguity on insurance decisions and the optimality of insurance contracts. My tractable approach allows me to study the interaction between risk and ambiguity attitudes. When insurance decisions are made independently of other assets, for a given increase in wealth, both risk...... portfolio theory that assumes Subjective Expected Utility theory; however, it provides hints to a possible solution of the under-diversification puzzle of households. I also identify conditions under which more risk or ambiguity aversion decreases the demand for coinsurance. Additionally, I show...... a counterexample to a classical result in insurance economics where an insurance contract with straight deductible is dominated by a coinsurance contract. Finally, I find that a modified Borch rule characterizes the optimal insurance contract with bilateral risk and ambiguity attitudes and heterogeneity in beliefs....

  15. Good luck, bad luck, and ambiguity aversion

    OpenAIRE

    Briony D. Pulford; Poonam Gill

    2014-01-01

    We report a series of experiments investigating the influence of feeling lucky or unlucky on people's choice of known-risk or ambiguous options using the traditional Ellsberg Urns decision-making task. We induced a state of feeling lucky or unlucky in subjects by using a rigged wheel-of-fortune game, which just missed either the bankrupt or the jackpot outcome. In the first experiment a large reversal of the usual ambiguity aversion effect was shown, indicating that feeling ...

  16. A Lexical Analysis Tool with Ambiguity Support

    OpenAIRE

    Quesada, Luis; Berzal, Fernando; Cortijo, Francisco J.

    2012-01-01

    Lexical ambiguities naturally arise in languages. We present Lamb, a lexical analyzer that produces a lexical analysis graph describing all the possible sequences of tokens that can be found within the input string. Parsers can process such lexical analysis graphs and discard any sequence of tokens that does not produce a valid syntactic sentence, therefore performing, together with Lamb, a context-sensitive lexical analysis in lexically-ambiguous language specifications.

  17. Relation between nonlinear models and gauge ambiguities

    International Nuclear Information System (INIS)

    Balachandran, A.P.; Ramachandran, R.; Rupertsberger, H.; Skagerstam, B.S.

    1980-01-01

    We show that the solutions of a class of nonlinear models also generate gauge ambiguities in the vacuum sector of Yang-Mills theories. Our results extend known connections between gauge ambiguities and certain nonlinear sigma-models, and clarify the underlying group theory. For many nonlinear models, we also give a simple, intrinsic parametrization of physical fields (which have values in a homogeneous space of a group). (orig.)

  18. On the ambiguity in relativistic tidal deformability

    Science.gov (United States)

    Gralla, Samuel E.

    2018-04-01

    The LIGO collaboration recently reported the first gravitational-wave constraints on the tidal deformability of neutron stars. I discuss an inherent ambiguity in the notion of relativistic tidal deformability that, while too small to affect the present measurement, may become important in the future. I propose a new way to understand the ambiguity and discuss future prospects for reliably linking observed gravitational waveforms to compact object microphysics.

  19. De morseir syndrome presenting as ambiguous genitalia

    OpenAIRE

    Anubhav Thukral; S Chitra; Partho P Chakraborty; Ajitesh Roy; Soumik Goswami; Rana Bhattacharjee; Deep Dutta; Indira Maisnam; Sujoy Ghosh; Satinath Mukherjee; Subhankar Chowdhury

    2012-01-01

    Background: A 10-year-old boy presented with genital ambiguity, poor linear growth, and delayed milestones. The aim and to highlight that although rare but congenital, hypogonadotropic hypogonadism may rarely present as ambiguity. Materials and Methods: The patient was found to have bilateral cryptorchidism with proximal penile hypospadias, microphallus with a proportionate dwarfism with mildly delayed bone age, and karyotype 46XY. Euthyroid with normal steroid axis, growth hormone insufficie...

  20. Probability judgments under ambiguity and conflict.

    Science.gov (United States)

    Smithson, Michael

    2015-01-01

    Whether conflict and ambiguity are distinct kinds of uncertainty remains an open question, as does their joint impact on judgments of overall uncertainty. This paper reviews recent advances in our understanding of human judgment and decision making when both ambiguity and conflict are present, and presents two types of testable models of judgments under conflict and ambiguity. The first type concerns estimate-pooling to arrive at "best" probability estimates. The second type is models of subjective assessments of conflict and ambiguity. These models are developed for dealing with both described and experienced information. A framework for testing these models in the described-information setting is presented, including a reanalysis of a multi-nation data-set to test best-estimate models, and a study of participants' assessments of conflict, ambiguity, and overall uncertainty reported by Smithson (2013). A framework for research in the experienced-information setting is then developed, that differs substantially from extant paradigms in the literature. This framework yields new models of "best" estimates and perceived conflict. The paper concludes with specific suggestions for future research on judgment and decision making under conflict and ambiguity.

  1. Precise Point Positioning with Partial Ambiguity Fixing.

    Science.gov (United States)

    Li, Pan; Zhang, Xiaohong

    2015-06-10

    Reliable and rapid ambiguity resolution (AR) is the key to fast precise point positioning (PPP). We propose a modified partial ambiguity resolution (PAR) method, in which an elevation and standard deviation criterion are first used to remove the low-precision ambiguity estimates for AR. Subsequently the success rate and ratio-test are simultaneously used in an iterative process to increase the possibility of finding a subset of decorrelated ambiguities which can be fixed with high confidence. One can apply the proposed PAR method to try to achieve an ambiguity-fixed solution when full ambiguity resolution (FAR) fails. We validate this method using data from 450 stations during DOY 021 to 027, 2012. Results demonstrate the proposed PAR method can significantly shorten the time to first fix (TTFF) and increase the fixing rate. Compared with FAR, the average TTFF for PAR is reduced by 14.9% for static PPP and 15.1% for kinematic PPP. Besides, using the PAR method, the average fixing rate can be increased from 83.5% to 98.2% for static PPP, from 80.1% to 95.2% for kinematic PPP respectively. Kinematic PPP accuracy with PAR can also be significantly improved, compared to that with FAR, due to a higher fixing rate.

  2. Recommendations for reducing ambiguity in written procedures.

    Energy Technology Data Exchange (ETDEWEB)

    Matzen, Laura E.

    2009-11-01

    Previous studies in the nuclear weapons complex have shown that ambiguous work instructions (WIs) and operating procedures (OPs) can lead to human error, which is a major cause for concern. This report outlines some of the sources of ambiguity in written English and describes three recommendations for reducing ambiguity in WIs and OPs. The recommendations are based on commonly used research techniques in the fields of linguistics and cognitive psychology. The first recommendation is to gather empirical data that can be used to improve the recommended word lists that are provided to technical writers. The second recommendation is to have a review in which new WIs and OPs and checked for ambiguities and clarity. The third recommendation is to use self-paced reading time studies to identify any remaining ambiguities before the new WIs and OPs are put into use. If these three steps are followed for new WIs and OPs, the likelihood of human errors related to ambiguity could be greatly reduced.

  3. Creative Brains: Designing in the Real World

    Directory of Open Access Journals (Sweden)

    Vinod eGoel

    2014-04-01

    Full Text Available The process of designing artifacts is a creative activity. It is proposed that, at the cognitive level, one key to understanding design creativity is to understand the array of symbol systems designers utilize. These symbol systems range from being vague, imprecise, abstract, ambiguous, and indeterminate (like conceptual sketches, to being very precise, concrete, unambiguous, and determinate (like contract documents. The former types of symbol systems support associative processes that facilitate lateral (or divergent transformations that broaden the problem space, while the latter types of symbol systems support inference processes facilitating vertical (or convergent transformations that deepen of the problem space. The process of artifact design requires the judicious application of both lateral and vertical transformations. This leads to a dual mechanism model of design problem-solving comprising of an associative engine and an inference engine. It is further claimed that this dual mechanism model is supported by an interesting hemispheric dissociation in human prefrontal cortex. The associative engine and neural structures that support imprecise, ambiguous, abstract, indeterminate representations are lateralized in the right prefrontal cortex, while the inference engine and neural structures that support precise, unambiguous, determinant representations are lateralized in the left prefrontal cortex. At the brain level, successful design of artifacts requires a delicate balance between the two hemispheres of prefrontal cortex.

  4. Varying acoustic-phonemic ambiguity reveals that talker normalization is obligatory in speech processing.

    Science.gov (United States)

    Choi, Ja Young; Hu, Elly R; Perrachione, Tyler K

    2018-04-01

    The nondeterministic relationship between speech acoustics and abstract phonemic representations imposes a challenge for listeners to maintain perceptual constancy despite the highly variable acoustic realization of speech. Talker normalization facilitates speech processing by reducing the degrees of freedom for mapping between encountered speech and phonemic representations. While this process has been proposed to facilitate the perception of ambiguous speech sounds, it is currently unknown whether talker normalization is affected by the degree of potential ambiguity in acoustic-phonemic mapping. We explored the effects of talker normalization on speech processing in a series of speeded classification paradigms, parametrically manipulating the potential for inconsistent acoustic-phonemic relationships across talkers for both consonants and vowels. Listeners identified words with varying potential acoustic-phonemic ambiguity across talkers (e.g., beet/boat vs. boot/boat) spoken by single or mixed talkers. Auditory categorization of words was always slower when listening to mixed talkers compared to a single talker, even when there was no potential acoustic ambiguity between target sounds. Moreover, the processing cost imposed by mixed talkers was greatest when words had the most potential acoustic-phonemic overlap across talkers. Models of acoustic dissimilarity between target speech sounds did not account for the pattern of results. These results suggest (a) that talker normalization incurs the greatest processing cost when disambiguating highly confusable sounds and (b) that talker normalization appears to be an obligatory component of speech perception, taking place even when the acoustic-phonemic relationships across sounds are unambiguous.

  5. RELATION OF COACHING BEHAVIOR AND ROLE AMBIGUITY

    Directory of Open Access Journals (Sweden)

    Karamousalidis G.

    2010-08-01

    Full Text Available The purpose of this research was to investigate the relationship between coaching behavior and role ambiguity in defensive responsibilities using interdependent Greek sport teams. Athlete perceptions of role ambiguity (defense were assessed using a questionnaire developed by Beauchamp, Bray, Eys and Carron (2002 andcoaching behavior was assessed using the Coaching Behavior Questionnaire, (Williams, et. al., 2003. The sample consisted of 409 athletes of basketball, volleyball, handball and soccer. Confirmatory factor analysis provided the construct validity of the questionnaires and correlations among the scales confirmed construct validity. The implications of the results are discussed and future research should continue to investigate the multidimensional models of both coaching behavior and role ambiguity in sport settings.

  6. Resolution of ambiguities in perturbative QCD

    International Nuclear Information System (INIS)

    Nakkagawa, Hisao; Niegawa, Akira.

    1984-01-01

    In the perturbative QCD analyses of the deeply inelastic processes, the coupling constant depends on at least two mass-scales, the renormalization scale and the factorization scale. By integrating the coupled renormalization group equations with respect to these two mass-scales, the running coupling constant is defined. A perturbative approximation then introduces a new ambiguity, the integration-path dependence, into the theory. We show that the problem of this new ambiguity is resolved by imposing Stevenson's principle of minimal sensitivity. Together with the analogous analysis of the operator matrix element or the cut vertex, we can completely solve the problem of getting an unambiguous perturbative QCD prediction. (author)

  7. Gene name ambiguity of eukaryotic nomenclatures.

    Science.gov (United States)

    Chen, Lifeng; Liu, Hongfang; Friedman, Carol

    2005-01-15

    With more and more scientific literature published online, the effective management and reuse of this knowledge has become problematic. Natural language processing (NLP) may be a potential solution by extracting, structuring and organizing biomedical information in online literature in a timely manner. One essential task is to recognize and identify genomic entities in text. 'Recognition' can be accomplished using pattern matching and machine learning. But for 'identification' these techniques are not adequate. In order to identify genomic entities, NLP needs a comprehensive resource that specifies and classifies genomic entities as they occur in text and that associates them with normalized terms and also unique identifiers so that the extracted entities are well defined. Online organism databases are an excellent resource to create such a lexical resource. However, gene name ambiguity is a serious problem because it affects the appropriate identification of gene entities. In this paper, we explore the extent of the problem and suggest ways to address it. We obtained gene information from 21 organisms and quantified naming ambiguities within species, across species, with English words and with medical terms. When the case (of letters) was retained, official symbols displayed negligible intra-species ambiguity (0.02%) and modest ambiguities with general English words (0.57%) and medical terms (1.01%). In contrast, the across-species ambiguity was high (14.20%). The inclusion of gene synonyms increased intra-species ambiguity substantially and full names contributed greatly to gene-medical-term ambiguity. A comprehensive lexical resource that covers gene information for the 21 organisms was then created and used to identify gene names by using a straightforward string matching program to process 45,000 abstracts associated with the mouse model organism while ignoring case and gene names that were also English words. We found that 85.1% of correctly retrieved mouse

  8. Quiver representations

    CERN Document Server

    Schiffler, Ralf

    2014-01-01

    This book is intended to serve as a textbook for a course in Representation Theory of Algebras at the beginning graduate level. The text has two parts. In Part I, the theory is studied in an elementary way using quivers and their representations. This is a very hands-on approach and requires only basic knowledge of linear algebra. The main tool for describing the representation theory of a finite-dimensional algebra is its Auslander-Reiten quiver, and the text introduces these quivers as early as possible. Part II then uses the language of algebras and modules to build on the material developed before. The equivalence of the two approaches is proved in the text. The last chapter gives a proof of Gabriel’s Theorem. The language of category theory is developed along the way as needed.

  9. Representational Machines

    DEFF Research Database (Denmark)

    Photography not only represents space. Space is produced photographically. Since its inception in the 19th century, photography has brought to light a vast array of represented subjects. Always situated in some spatial order, photographic representations have been operatively underpinned by social...... to the enterprises of the medium. This is the subject of Representational Machines: How photography enlists the workings of institutional technologies in search of establishing new iconic and social spaces. Together, the contributions to this edited volume span historical epochs, social environments, technological...... possibilities, and genre distinctions. Presenting several distinct ways of producing space photographically, this book opens a new and important field of inquiry for photography research....

  10. Group representations

    CERN Document Server

    Karpilovsky, G

    1994-01-01

    This third volume can be roughly divided into two parts. The first part is devoted to the investigation of various properties of projective characters. Special attention is drawn to spin representations and their character tables and to various correspondences for projective characters. Among other topics, projective Schur index and projective representations of abelian groups are covered. The last topic is investigated by introducing a symplectic geometry on finite abelian groups. The second part is devoted to Clifford theory for graded algebras and its application to the corresponding theory

  11. Value Representations

    DEFF Research Database (Denmark)

    Rasmussen, Majken Kirkegaard; Petersen, Marianne Graves

    2011-01-01

    Stereotypic presumptions about gender affect the design process, both in relation to how users are understood and how products are designed. As a way to decrease the influence of stereotypic presumptions in design process, we propose not to disregard the aspect of gender in the design process......, as the perspective brings valuable insights on different approaches to technology, but instead to view gender through a value lens. Contributing to this perspective, we have developed Value Representations as a design-oriented instrument for staging a reflective dialogue with users. Value Representations...

  12. Metaphores et representations du cerveau plurilingue: conceptions naives ou construction du savior? Exemples dans le contexte d'enseignement andorran (Metaphors and Representations of the Multilingual Brain: Naive Conceptions or Knowledge Construction? Examples in the Context of Andorran Education).

    Science.gov (United States)

    Larruy, Martine Marquillo

    2000-01-01

    This article concentrates on the use of metaphors characterizing a multilingual brain in a corpus of oral interactions drawn from the Andorran part of an international research study. First, the situation and the status of metaphors in fields connected to the elaboration of knowledge is questioned. Next, the most important metaphors associated to…

  13. Symbol in Point View of Ambiguity

    Directory of Open Access Journals (Sweden)

    Dr. M. R. Yousefi

    Full Text Available Symbol from the perspective of rhetorical word, is phrase or sentence that apparent meaning, also inspires to reader a wide range of semantic.Since exploring the complex social and political ideas in the most mysticalway and indirectreflectionsocial and political thoughts symbolically is easier, so the symbol and symbolism especially in Persian literatureespeciallyin the realm of Persian poetry, has a special appearance.In addition to the factors mentioned in the contemporary literature, according familiar in literature and the emergence of particular schools interest toambiguoussymbolization has spreadfurther, especially the symbol has all the features of art ambiguity in the poem and it isone the major factors causing uncertainty.Thus, the precise definitions and symbols of contemporary poetry could be dominant in the unwinding ambiguous symbol detection of cryptic allusions and metaphors that matches the cursor symbol to help readers.In the literature, especially language poetry, the inability of language toreflecting obscure mystical ideas, avoid to directexpression of political and social concerns of the reader in the course of participate to creation ambiguous literary works is the main motivation towards symbol and symbolization.According widespread use of symbol and its different of species can be viewed from different perspectives.The creation of ambiguity is the main purposes of using symbols (especially in poetry, so many poets have tried to achieve this goal have to formation of similar symbols and the explanation and resolution of this issue can open new window for understanding the poetry in front of an audience.In this paper examines the ambiguity of symbols in terms of its precise boundaries are reviewed. Ambiguity is one of the important processes and also is the key Iranian poetry; its means is today poetry. In such poetry ambiguity is a need to explore the new world from a different perspective, or explore this complex world

  14. Knowledge representation and natural language processing

    Energy Technology Data Exchange (ETDEWEB)

    Weischedel, R.M.

    1986-07-01

    In principle, natural language and knowledge representation are closely related. This paper investigates this by demonstrating how several natural language phenomena, such as definite reference, ambiguity, ellipsis, ill-formed input, figures of speech, and vagueness, require diverse knowledge sources and reasoning. The breadth of kinds of knowledge needed to represent morphology, syntax, semantics, and pragmatics is surveyed. Furthermore, several current issues in knowledge representation, such as logic versus semantic nets, general-purpose versus special-purpose reasoners, adequacy of first-order logic, wait-and-see strategies, and default reasoning, are illustrated in terms of their relation to natural language processing and how natural language impact the issues.

  15. Exploring Situated Ambiguity in Students' Entrepreneurial Learning

    Science.gov (United States)

    Kubberød, Elin; Pettersen, Inger Beate

    2017-01-01

    Purpose: Building on entrepreneurial learning research, the purpose of this paper is to argue that the students participating in foreign entrepreneurial education programmes can have realistic entrepreneurial learning experiences. This research addresses two specific questions: how situated ambiguity induced by a foreign culture may contribute to…

  16. The Ambiguous Role of Constraints in Creativity

    DEFF Research Database (Denmark)

    Biskjær, Michael Mose; Onarheim, Balder; Wiltschnig, Stefan

    2011-01-01

    The relationship between creativity and constraints is often described in the literature either in rather imprecise, general concepts or in relation to very specific domains. Cross-domain and cross-disciplinary takes on how the handling of constraints influences creative activities are rare. In t......-disciplinary research into the ambiguous role of constraints in creativity....

  17. Ambiguous diagnosis, futile treatments and temporary recovery ...

    African Journals Online (AJOL)

    Ambiguous diagnosis, futile treatments and temporary recovery: Meanings of medical treatment among HIV/AIDS family caregivers providing care without ARVs. ... to understand unstable treatment outcomes; and policy makers should strengthen home-based care by developing policies that integrate palliative care into HIV ...

  18. Representational Thickness

    DEFF Research Database (Denmark)

    Mullins, Michael

    Contemporary communicational and informational processes contribute to the shaping of our physical environment by having a powerful influence on the process of design. Applications of virtual reality (VR) are transforming the way architecture is conceived and produced by introducing dynamic...... elements into the process of design. Through its immersive properties, virtual reality allows access to a spatial experience of a computer model very different to both screen based simulations as well as traditional forms of architectural representation. The dissertation focuses on processes of the current...... representation? How is virtual reality used in public participation and how do virtual environments affect participatory decision making? How does VR thus affect the physical world of built environment? Given the practical collaborative possibilities of immersive technology, how can they best be implemented...

  19. Quadri-stability of a spatially ambiguous auditory illusion

    Directory of Open Access Journals (Sweden)

    Constance May Bainbridge

    2015-01-01

    Full Text Available In addition to vision, audition plays an important role in sound localization in our world. One way we estimate the motion of an auditory object moving towards or away from us is from changes in volume intensity. However, the human auditory system has unequally distributed spatial resolution, including difficulty distinguishing sounds in front versus behind the listener. Here, we introduce a novel quadri-stable illusion, the Transverse-and-Bounce Auditory Illusion, which combines front-back confusion with changes in volume levels of a nonspatial sound to create ambiguous percepts of an object approaching and withdrawing from the listener. The sound can be perceived as traveling transversely from front to back or back to front, or bouncing to remain exclusively in front of or behind the observer. Here we demonstrate how human listeners experience this illusory phenomenon by comparing ambiguous and unambiguous stimuli for each of the four possible motion percepts. When asked to rate their confidence in perceiving each sound’s motion, participants reported equal confidence for the illusory and unambiguous stimuli. Participants perceived all four illusory motion percepts, and could not distinguish the illusion from the unambiguous stimuli. These results show that this illusion is effectively quadri-stable. In a second experiment, the illusory stimulus was looped continuously in headphones while participants identified its perceived path of motion to test properties of perceptual switching, locking, and biases. Participants were biased towards perceiving transverse compared to bouncing paths, and they became perceptually locked into alternating between front-to-back and back-to-front percepts, perhaps reflecting how auditory objects commonly move in the real world. This multi-stable auditory illusion opens opportunities for studying the perceptual, cognitive, and neural representation of objects in motion, as well as exploring multimodal perceptual

  20. Interpretative bias in spider phobia: Perception and information processing of ambiguous schematic stimuli.

    Science.gov (United States)

    Haberkamp, Anke; Schmidt, Filipp

    2015-09-01

    This study investigates the interpretative bias in spider phobia with respect to rapid visuomotor processing. We compared perception, evaluation, and visuomotor processing of ambiguous schematic stimuli between spider-fearful and control participants. Stimuli were produced by gradually morphing schematic flowers into spiders. Participants rated these stimuli related to their perceptual appearance and to their feelings of valence, disgust, and arousal. Also, they responded to the same stimuli within a response priming paradigm that measures rapid motor activation. Spider-fearful individuals showed an interpretative bias (i.e., ambiguous stimuli were perceived as more similar to spiders) and rated spider-like stimuli as more unpleasant, disgusting, and arousing. However, we observed no differences between spider-fearful and control participants in priming effects for ambiguous stimuli. For non-ambiguous stimuli, we observed a similar enhancement for phobic pictures as has been reported previously for natural images. We discuss our findings with respect to the visual representation of morphed stimuli and to perceptual learning processes. Copyright © 2015 Elsevier B.V. All rights reserved.

  1. Measuring ambiguity in HLA typing methods.

    Directory of Open Access Journals (Sweden)

    Vanja Paunić

    Full Text Available In hematopoietic stem cell transplantation, donor selection is based primarily on matching donor and patient HLA genes. These genes are highly polymorphic and their typing can result in exact allele assignment at each gene (the resolution at which patients and donors are matched, but it can also result in a set of ambiguous assignments, depending on the typing methodology used. To facilitate rapid identification of matched donors, registries employ statistical algorithms to infer HLA alleles from ambiguous genotypes. Linkage disequilibrium information encapsulated in haplotype frequencies is used to facilitate prediction of the most likely haplotype assignment. An HLA typing with less ambiguity produces fewer high-probability haplotypes and a more reliable prediction. We estimated ambiguity for several HLA typing methods across four continental populations using an information theory-based measure, Shannon's entropy. We used allele and haplotype frequencies to calculate entropy for different sets of 1,000 subjects with simulated HLA typing. Using allele frequencies we calculated an average entropy in Caucasians of 1.65 for serology, 1.06 for allele family level, 0.49 for a 2002-era SSO kit, and 0.076 for single-pass SBT. When using haplotype frequencies in entropy calculations, we found average entropies of 0.72 for serology, 0.73 for allele family level, 0.05 for SSO, and 0.002 for single-pass SBT. Application of haplotype frequencies further reduces HLA typing ambiguity. We also estimated expected confirmatory typing mismatch rates for simulated subjects. In a hypothetical registry with all donors typed using the same method, the entropy values based on haplotype frequencies correspond to confirmatory typing mismatch rates of 1.31% for SSO versus only 0.08% for SBT. Intermediate-resolution single-pass SBT contains the least ambiguity of the methods we evaluated and therefore the most certainty in allele prediction. The presented measure

  2. Measuring Ambiguity in HLA Typing Methods

    Science.gov (United States)

    Madbouly, Abeer; Freeman, John; Maiers, Martin

    2012-01-01

    In hematopoietic stem cell transplantation, donor selection is based primarily on matching donor and patient HLA genes. These genes are highly polymorphic and their typing can result in exact allele assignment at each gene (the resolution at which patients and donors are matched), but it can also result in a set of ambiguous assignments, depending on the typing methodology used. To facilitate rapid identification of matched donors, registries employ statistical algorithms to infer HLA alleles from ambiguous genotypes. Linkage disequilibrium information encapsulated in haplotype frequencies is used to facilitate prediction of the most likely haplotype assignment. An HLA typing with less ambiguity produces fewer high-probability haplotypes and a more reliable prediction. We estimated ambiguity for several HLA typing methods across four continental populations using an information theory-based measure, Shannon's entropy. We used allele and haplotype frequencies to calculate entropy for different sets of 1,000 subjects with simulated HLA typing. Using allele frequencies we calculated an average entropy in Caucasians of 1.65 for serology, 1.06 for allele family level, 0.49 for a 2002-era SSO kit, and 0.076 for single-pass SBT. When using haplotype frequencies in entropy calculations, we found average entropies of 0.72 for serology, 0.73 for allele family level, 0.05 for SSO, and 0.002 for single-pass SBT. Application of haplotype frequencies further reduces HLA typing ambiguity. We also estimated expected confirmatory typing mismatch rates for simulated subjects. In a hypothetical registry with all donors typed using the same method, the entropy values based on haplotype frequencies correspond to confirmatory typing mismatch rates of 1.31% for SSO versus only 0.08% for SBT. Intermediate-resolution single-pass SBT contains the least ambiguity of the methods we evaluated and therefore the most certainty in allele prediction. The presented measure objectively evaluates HLA

  3. Nonlinear Suppression of Range Ambiguity in Pulse Doppler Radar

    National Research Council Canada - National Science Library

    Anderson, Jon

    2001-01-01

    ... ambiguities in Doppler and range. First introduced by Palermo in 1962 using two conjugate LFM pulses, the primary nonlinear suppression objective involves reducing range ambiguity, given the waveform is nominally unambiguous...

  4. Positive fEMG Patterns with Ambiguity in Paintings.

    Science.gov (United States)

    Jakesch, Martina; Goller, Juergen; Leder, Helmut

    2017-01-01

    Whereas ambiguity in everyday life is often negatively evaluated, it is considered key in art appreciation. In a facial EMG study, we tested whether the positive role of visual ambiguity in paintings is reflected in a continuous affective evaluation on a subtle level. We presented ambiguous (disfluent) and non-ambiguous (fluent) versions of Magritte paintings and found that M. Zygomaticus major activation was higher and M. corrugator supercilii activation was lower for ambiguous than for non-ambiguous versions. Our findings reflect a positive continuous affective evaluation to visual ambiguity in paintings over the 5 s presentation time. We claim that this finding is indirect evidence for the hypothesis that visual stimuli classified as art, evoke a safe state for indulging into experiencing ambiguity, challenging the notion that processing fluency is generally related to positive affect.

  5. 2.5D Representations Combining in vivo 3D MRI and ex vivo 2D MSI Approaches to Study the Lipid Distribution in the Whole Sheep Brain

    OpenAIRE

    Labas , Valérie; Teixeira-Gomes , Ana Paula; Andersson , Frédéric; Ménigot , Sébastien; Batailler , Martine; Adriaensen , Hans; Migaud , Martine; Chaillou , Elodie

    2015-01-01

    National audience; Mass Spectrometry Imaging (MSI) provides easily high spatially resolved masses allowing characterization of endogenous lipids. These latter constitute about 70% of the composition of the white matter of the brain which can be implicated in developmental and/or cognitive troubles. In order to examine the molecular distribution of lipids in whole sheep brain, and especially in white/grey matter, we combined in vivo and ex vivo images, obtained in the same animals, using Magne...

  6. Discrete ambiguities in CP-violating asymmetries in B decays

    International Nuclear Information System (INIS)

    London, David

    1998-01-01

    The CP-angles α, β and γ can be extracted from CP-violating asymmetries in the B system, but only up to discrete ambiguities. These discrete ambiguities make it difficult to determine with certainty whether or not new physics is present. I show that, if the condition α+β+γ=π is imposed, there remains a twofold ambiguity in the CP-angle set (α,β,γ), and I discuss ways to cleanly resolve this final discrete ambiguity

  7. Hippocampal Processing of Ambiguity Enhances Fear Memory.

    Science.gov (United States)

    Amadi, Ugwechi; Lim, Seh Hong; Liu, Elizabeth; Baratta, Michael V; Goosens, Ki A

    2017-02-01

    Despite the ubiquitous use of Pavlovian fear conditioning as a model for fear learning, the highly predictable conditions used in the laboratory do not resemble real-world conditions, in which dangerous situations can lead to unpleasant outcomes in unpredictable ways. In the current experiments, we varied the timing of aversive events after predictive cues in rodents and discovered that temporal ambiguity of aversive events greatly enhances fear. During fear conditioning with unpredictably timed aversive events, pharmacological inactivation of the dorsal hippocampus or optogenetic silencing of cornu ammonis 1 cells during aversive negative prediction errors prevented this enhancement of fear without affecting fear learning for predictable events. Dorsal hippocampal inactivation also prevented ambiguity-related enhancement of fear during auditory fear conditioning under a partial-reinforcement schedule. These results reveal that information about the timing and occurrence of aversive events is rapidly acquired and that unexpectedly timed or omitted aversive events generate hippocampal signals to enhance fear learning.

  8. Optimal observables and phase-space ambiguities

    International Nuclear Information System (INIS)

    Nachtmann, O.; Nagel, F.

    2005-01-01

    Optimal observables are known to lead to minimal statistical errors on parameters for a given normalised event distribution of a physics reaction. Thereby all statistical correlations are taken into account. Therefore, on the one hand they are a useful tool to extract values on a set of parameters from measured data. On the other hand one can calculate the minimal constraints on these parameters achievable by any data-analysis method for the specific reaction. In case the final states can be reconstructed without ambiguities optimal observables have a particularly simple form. We give explicit formulae for the optimal observables for generic reactions in case of ambiguities in the reconstruction of the final state and for general parameterisation of the final-state phase space. (orig.)

  9. Learning, Teaching and Ambiguity in Virtual Worlds

    Science.gov (United States)

    Carr, Diane; Oliver, Martin; Burn, Andrew

    What might online communities and informal learning practices teach us about virtual world pedagogy? In this chapter we describe a research project in which learning practices in online worlds such as World of Warcraft and Second LifeTM (SL) were investigated. Working within an action research framework, we employed a range of methods to investigate how members of online communities define the worlds they encounter, negotiate the terms of participation, and manage the incremental complexity of game worlds. The implications of such practices for online pedagogy were then explored through teaching in SL. SL eludes simple definitions. Users, or "residents", of SL partake of a range of pleasures and activities - socialising, building, creating and exhibiting art, playing games, exploring, shopping, or running a business, for instance. We argue that the variable nature of SL gives rise to degrees of ambiguity. This ambiguity impacts on inworld social practices, and has significant implications for online teaching and learning.

  10. Auditory motion capturing ambiguous visual motion

    Directory of Open Access Journals (Sweden)

    Arjen eAlink

    2012-01-01

    Full Text Available In this study, it is demonstrated that moving sounds have an effect on the direction in which one sees visual stimuli move. During the main experiment sounds were presented consecutively at four speaker locations inducing left- or rightwards auditory apparent motion. On the path of auditory apparent motion, visual apparent motion stimuli were presented with a high degree of directional ambiguity. The main outcome of this experiment is that our participants perceived visual apparent motion stimuli that were ambiguous (equally likely to be perceived as moving left- or rightwards more often as moving in the same direction than in the opposite direction of auditory apparent motion. During the control experiment we replicated this finding and found no effect of sound motion direction on eye movements. This indicates that auditory motion can capture our visual motion percept when visual motion direction is insufficiently determinate without affecting eye movements.

  11. An Investigation into Ambiguity Tolerance in Iranian Senior EFL Undergraduates

    Science.gov (United States)

    Marzban, Amin; Barati, Hossein; Moinzadeh, Ahmad

    2012-01-01

    The present study aimed to explore how tolerant of ambiguity Iranian EFL learners at university level are and if gender plays a role in this regard. To this end, upon filling in the revised SLTAS scale of ambiguity tolerance 194 male and female Iranian teacher trainees were assigned to three ambiguity tolerance groups; namely, high, moderate and…

  12. Does ambiguity aversion survive in experimental asset markets?

    NARCIS (Netherlands)

    Füllbrunn, Sascha; Rau, Holger A.; Weitzel, Utz

    2014-01-01

    Although a number of theoretical studies explain empirical puzzles in finance with ambiguity aversion, it is not a given that individual ambiguity attitudes survive in markets. In fact, despite ample evidence of ambiguity aversion in individual decision making, most studies find no or only limited

  13. Portfolio Management with Stochastic Interest Rates and Inflation Ambiguity

    DEFF Research Database (Denmark)

    Munk, Claus; Rubtsov, Alexey Vladimirovich

    2014-01-01

    prices. The investor is ambiguous about the inflation model and prefers a portfolio strategy which is robust to model misspecification. Ambiguity about the inflation dynamics is shown to affect the optimal portfolio fundamentally different than ambiguity about the price dynamics of traded assets...

  14. Ambiguity in the Acquisition of Lexical Information

    OpenAIRE

    Vanderwende, Lucy

    1995-01-01

    This paper describes an approach to the automatic identification of lexical information in on-line dictionaries. This approach uses bootstrapping techniques, specifically so that ambiguity in the dictionary text can be treated properly. This approach consists of processing an on-line dictionary multiple times, each time refining the lexical information previously acquired and identifying new lexical information. The strength of this approach is that lexical information can be acquired from de...

  15. A mixture approach to vagueness and ambiguity.

    Directory of Open Access Journals (Sweden)

    Steven Verheyen

    Full Text Available When asked to indicate which items from a set of candidates belong to a particular natural language category inter-individual differences occur: Individuals disagree which items should be considered category members. The premise of this paper is that these inter-individual differences in semantic categorization reflect both ambiguity and vagueness. Categorization differences are said to be due to ambiguity when individuals employ different criteria for categorization. For instance, individuals may disagree whether hiking or darts is the better example of sports because they emphasize respectively whether an activity is strenuous and whether rules apply. Categorization differences are said to be due to vagueness when individuals employ different cut-offs for separating members from non-members. For instance, the decision to include hiking in the sports category or not, may hinge on how strenuous different individuals require sports to be. This claim is supported by the application of a mixture model to categorization data for eight natural language categories. The mixture model can identify latent groups of categorizers who regard different items likely category members (i.e., ambiguity with categorizers within each of the groups differing in their propensity to provide membership responses (i.e., vagueness. The identified subgroups are shown to emphasize different sets of category attributes when making their categorization decisions.

  16. Evaluation of ambiguous genitalia with MR imaging

    International Nuclear Information System (INIS)

    Secaf, E.; Nuruddin, R.; Hricak, H.; Conte, F.A.

    1989-01-01

    To assess the potential of MR imaging in the evaluation of patients with ambiguous genitalia. Twenty-three consecutive patients with ambiguous genitalia at birth or phenotypic anomalies at puberty were included in this study. MR imaging was performed on a 1.5-T unit using T1- (600/30) and T2- (2,500/70) weighted sequences. In patients aged 5 years or less, 3-mm contiguous sagittal and transaxial sections were obtained. The same imaging planes at 5-mm intervals were obtained in older patients. MR findings were compared to those of surgery (n = 14) or biochemical assays (n = 9). Diagnoses included true hermaphroditism (n = 2), pseudohermaphroditism (n = 6), Turner syndrome (n = 2), testicular feminization (n = 2), adrenogenital syndrome (n = 3), vaginal agenesis (n = 3), cloacal abnormality (n = 2), microphallus (n = 2), and double phallus (n = 1. MR imaging correctly identified the presence or absence of the vagina (n = 10) and uterus (n = 9), thus helping in the diagnosis and management of patients with ambiguous genitalia. Demonstration of development of corpora cavernosa, corpora spongiosa, undescended testis, or partial vaginal agenesis assisted in the surgical approach

  17. Phonological ambiguity modulates resolution of semantic ambiguity during reading: An fMRI study of Hebrew.

    Science.gov (United States)

    Bitan, Tali; Kaftory, Asaf; Meiri-Leib, Adi; Eviatar, Zohar; Peleg, Orna

    2017-10-01

    The current fMRI study examined the role of phonology in the extraction of meaning from print in each hemisphere by comparing homophonic and heterophonic homographs (ambiguous words in which both meanings have the same or different sounds respectively, e.g., bank or tear). The analysis distinguished between the first phase, in which participants read ambiguous words without context, and the second phase in which the context resolves the ambiguity. Native Hebrew readers were scanned during semantic relatedness judgments on pairs of words in which the first word was either a homophone or a heterophone and the second word was related to its dominant or subordinate meaning. In Phase 1 there was greater activation for heterophones in left inferior frontal gyrus (IFG), pars opercularis, and more activation for homophones in bilateral IFG pars orbitalis, suggesting that resolution of the conflict at the phonological level has abolished the semantic ambiguity for heterophones. Reduced activation for all ambiguous words in temporo-parietal regions suggests that although ambiguity enhances controlled lexical selection processes in frontal regions it reduces reliance on bottom-up mapping processes. After presentation of the context, a larger difference between the dominant and subordinate meaning was found for heterophones in all reading-related regions, suggesting a greater engagement for heterophones with the dominant meaning. Altogether these results are consistent with the prominent role of phonological processing in visual word recognition. Finally, despite differences in hemispheric asymmetry between homophones and heterophones, ambiguity resolution, even toward the subordinate meaning, is largely left lateralized. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

  18. On coherent-state representations of quantum mechanics: Wave mechanics in phase space

    DEFF Research Database (Denmark)

    Møller, Klaus Braagaard; Jørgensen, Thomas Godsk; Torres-Vega, Gabino

    1997-01-01

    In this article we argue that the state-vector phase-space representation recently proposed by Torres-Vega and co-workers [introduced in J. Chem. Phys. 98, 3103 (1993)] coincides with the totality of coherent-state representations for the Heisenberg-Weyl group. This fact leads to ambiguities when...

  19. Ambiguities and conventions in the perception of visual art.

    Science.gov (United States)

    Mamassian, Pascal

    2008-09-01

    Vision perception is ambiguous and visual arts play with these ambiguities. While perceptual ambiguities are resolved with prior constraints, artistic ambiguities are resolved by conventions. Is there a relationship between priors and conventions? This review surveys recent work related to these ambiguities in composition, spatial scale, illumination and color, three-dimensional layout, shape, and movement. While most conventions seem to have their roots in perceptual constraints, those conventions that differ from priors may help us appreciate how visual arts differ from everyday perception.

  20. Pricing risk and ambiguity: the effect of perspective taking.

    Science.gov (United States)

    Trautmann, Stefan T; Schmidt, Ulrich

    2012-01-01

    In the valuation of uncertain prospects, a difference is often observed between selling and buying perspectives. This paper distinguishes between risk (known probabilities) and ambiguity (unknown probabilities) in decisions under uncertainty and shows that the valuation disparity increases under ambiguity compared to risk. It is found that both the comparative versus noncomparative evaluation of risky and ambiguous prospects and the uniqueness of the valuation perspective (either seller or buyer) moderate this increase in the disparity under ambiguity. The finding is consistent with recent theoretical accounts of pricing under uncertainty. We discuss implications for market behaviour and for the ambiguity paradigm as a research tool.

  1. Ambiguity Within Nursing Practice: An Evolutionary Concept Analysis.

    Science.gov (United States)

    McMahon, Michelle A; Dluhy, Nancy M

    2017-02-01

    To analyze the concept of ambiguity in a nursing context. Ambiguity is inherent within nursing practice. As health care becomes increasingly complex, nurses must continue to successfully deal with greater amounts of clinical ambiguity. Although ambiguity is discussed in nursing, minimal concept refinement exists to capture the contextual intricacies from a nursing lens. Nurse perception of an ambiguous clinical event, in combination with nurse tolerance level for ambiguity, can impact nurse response. Yet, little is known about what constitutes ambiguity within nursing practice (AWNP). Rodgers evolutionary method was used to explore AWNP, with emphasis on nurse thinking during ambiguous clinical situations. Literature searches across multiple databases yielded 38 articles for analysis. Attributes of AWNP include (a) variations in cues/available information, (b) multiple interpretations, (c) novel/nonroutine presentations, and (d) unpredictable. Antecedents include (a) a context-specific, clinical situation with ambiguous features needing evaluation and (b) an individual to sense a knowledge gap or perceive ambiguity. Consequences include ranges of (a) emotional, (b) behavioral, and (c) cognitive clinician responses. Preliminary findings support AWNP as a distinct concept in which ambiguity perceived by the nurse likely affects judgment, decision making, and clinical interventions. AWNP is a clinically relevant concept requiring continued development.

  2. Potential Ambiguity Translation Performances within Legal Language Institutional Nomenclature

    Directory of Open Access Journals (Sweden)

    Oţăt Diana

    2015-12-01

    Full Text Available Motivated by a paradoxical corollary of ambiguities in legal documents and especially in contract texts, the current paper underpins a dichotomy approach to unintended ambiguities aiming to establish a referential framework for the occurrence rate of translation ambiguities within the legal language nomenclature. The research focus is on a twofold situation since ambiguities may. on the one hand, arise dining the translation process, generated by the translator’s lack of competence, i.e. inadequate use of English regarding the special nature of legal language, or. on the other hand, they may be simply transferred from the source language into the target language without even noticing the potential ambiguous situation, i.e. culture-bound ambiguities. Hence, the paper proposes a contrastive analysis in order to localize the occurrence of lexical, structural, and socio-cultural ambiguities triggered by the use of the term performance and its Romanian equivalents in a number of sales contracts.

  3. Children do not exhibit ambiguity aversion despite intact familiarity bias.

    Science.gov (United States)

    Li, Rosa; Brannon, Elizabeth M; Huettel, Scott A

    2014-01-01

    The phenomenon of ambiguity aversion, in which risky gambles with known probabilities are preferred over ambiguous gambles with unknown probabilities, has been thoroughly documented in adults but never measured in children. Here, we use two distinct tasks to investigate ambiguity preferences of children (8- to 9-year-olds) and a comparison group of adults (19- to 27-year-olds). Across three separate measures, we found evidence for significant ambiguity aversion in adults but not in children and for greater ambiguity aversion in adults compared to children. As ambiguity aversion in adults has been theorized to result from a preference to bet on the known and avoid the unfamiliar, we separately measured familiarity bias and found that children, like adults, are biased towards the familiar. Our findings indicate that ambiguity aversion emerges across the course of development between childhood and adolescence, while a familiarity bias is already present in childhood.

  4. Does ambiguity aversion influence the framing effect during decision making?

    Science.gov (United States)

    Osmont, Anaïs; Cassotti, Mathieu; Agogué, Marine; Houdé, Olivier; Moutier, Sylvain

    2015-04-01

    Decision-makers present a systematic tendency to avoid ambiguous options for which the level of risk is unknown. This ambiguity aversion is one of the most striking decision-making biases. Given that human choices strongly depend on the options' presentation, the purpose of the present study was to examine whether ambiguity aversion influences the framing effect during decision making. We designed a new financial decision-making task involving the manipulation of both frame and uncertainty levels. Thirty-seven participants had to choose between a sure option and a gamble depicting either clear or ambiguous probabilities. The results revealed a clear preference for the sure option in the ambiguity condition regardless of frame. However, participants presented a framing effect in both the risk and ambiguity conditions. Indeed, the framing effect was bidirectional in the risk condition and unidirectional in the ambiguity condition given that it did not involve preference reversal but only a more extreme choice tendency.

  5. Optimal combination of illusory and luminance-defined 3-D surfaces: A role for ambiguity.

    Science.gov (United States)

    Hartle, Brittney; Wilcox, Laurie M; Murray, Richard F

    2018-04-01

    The shape of the illusory surface in stereoscopic Kanizsa figures is determined by the interpolation of depth from the luminance edges of adjacent inducing elements. Despite ambiguity in the position of illusory boundaries, observers reliably perceive a coherent three-dimensional (3-D) surface. However, this ambiguity may contribute additional uncertainty to the depth percept beyond what is expected from measurement noise alone. We evaluated the intrinsic ambiguity of illusory boundaries by using a cue-combination paradigm to measure the reliability of depth percepts elicited by stereoscopic illusory surfaces. We assessed the accuracy and precision of depth percepts using 3-D Kanizsa figures relative to luminance-defined surfaces. The location of the surface peak was defined by illusory boundaries, luminance-defined edges, or both. Accuracy and precision were assessed using a depth-discrimination paradigm. A maximum likelihood linear cue combination model was used to evaluate the relative contribution of illusory and luminance-defined signals to the perceived depth of the combined surface. Our analysis showed that the standard deviation of depth estimates was consistent with an optimal cue combination model, but the points of subjective equality indicated that observers consistently underweighted the contribution of illusory boundaries. This systematic underweighting may reflect a combination rule that attributes additional intrinsic ambiguity to the location of the illusory boundary. Although previous studies show that illusory and luminance-defined contours share many perceptual similarities, our model suggests that ambiguity plays a larger role in the perceptual representation of illusory contours than of luminance-defined contours.

  6. Flexible taxonomic assignment of ambiguous sequencing reads

    Directory of Open Access Journals (Sweden)

    Jansson Jesper

    2011-01-01

    Full Text Available Abstract Background To characterize the diversity of bacterial populations in metagenomic studies, sequencing reads need to be accurately assigned to taxonomic units in a given reference taxonomy. Reads that cannot be reliably assigned to a unique leaf in the taxonomy (ambiguous reads are typically assigned to the lowest common ancestor of the set of species that match it. This introduces a potentially severe error in the estimation of bacteria present in the sample due to false positives, since all species in the subtree rooted at the ancestor are implicitly assigned to the read even though many of them may not match it. Results We present a method that maps each read to a node in the taxonomy that minimizes a penalty score while balancing the relevance of precision and recall in the assignment through a parameter q. This mapping can be obtained in time linear in the number of matching sequences, because LCA queries to the reference taxonomy take constant time. When applied to six different metagenomic datasets, our algorithm produces different taxonomic distributions depending on whether coverage or precision is maximized. Including information on the quality of the reads reduces the number of unassigned reads but increases the number of ambiguous reads, stressing the relevance of our method. Finally, two measures of performance are described and results with a set of artificially generated datasets are discussed. Conclusions The assignment strategy of sequencing reads introduced in this paper is a versatile and a quick method to study bacterial communities. The bacterial composition of the analyzed samples can vary significantly depending on how ambiguous reads are assigned depending on the value of the q parameter. Validation of our results in an artificial dataset confirm that a combination of values of q produces the most accurate results.

  7. Complexities of three dimensional part geometry. [Ambiguities in specification of pieces for manufacture

    Energy Technology Data Exchange (ETDEWEB)

    Stark, R.H.

    1977-05-01

    This report is a non-technical exposition on the ambiguities in conventional specification of the shape of a part to be manufactured and on various alternatives for representing its geometry for computer processing. It touches lightly on wire-frame and bounded surface representations and on the concept of design by volumes. It concludes that no existing computer-aided design system has yet shown its long-range superiority over he spectrum of parts and of uses to which its information base should be applicable. 9 figures.

  8. Ambiguity of Quality in Remote Sensing Data

    Science.gov (United States)

    Lynnes, Christopher; Leptoukh, Greg

    2010-01-01

    This slide presentation reviews some of the issues in quality of remote sensing data. Data "quality" is used in several different contexts in remote sensing data, with quite different meanings. At the pixel level, quality typically refers to a quality control process exercised by the processing algorithm, not an explicit declaration of accuracy or precision. File level quality is usually a statistical summary of the pixel-level quality but is of doubtful use for scenes covering large areal extents. Quality at the dataset or product level, on the other hand, usually refers to how accurately the dataset is believed to represent the physical quantities it purports to measure. This assessment often bears but an indirect relationship at best to pixel level quality. In addition to ambiguity at different levels of granularity, ambiguity is endemic within levels. Pixel-level quality terms vary widely, as do recommendations for use of these flags. At the dataset/product level, quality for low-resolution gridded products is often extrapolated from validation campaigns using high spatial resolution swath data, a suspect practice at best. Making use of quality at all levels is complicated by the dependence on application needs. We will present examples of the various meanings of quality in remote sensing data and possible ways forward toward a more unified and usable quality framework.

  9. Our Brains Extended

    Science.gov (United States)

    Prensky, Marc

    2013-01-01

    Technology is an extension of the brain; it is a new way of thinking. It is the solution humans have created to deal with the difficult new context of variability, uncertainty, complexity, and ambiguity. Wise integration of evolving and powerful technology demands a rethinking of the curriculum. This article discusses technology as the new way of…

  10. Ambiguity aversion in schizophrenia: An fMRI study of decision-making under risk and ambiguity.

    Science.gov (United States)

    Fujino, Junya; Hirose, Kimito; Tei, Shisei; Kawada, Ryosaku; Tsurumi, Kosuke; Matsukawa, Noriko; Miyata, Jun; Sugihara, Genichi; Yoshihara, Yujiro; Ideno, Takashi; Aso, Toshihiko; Takemura, Kazuhisa; Fukuyama, Hidenao; Murai, Toshiya; Takahashi, Hidehiko

    2016-12-01

    When making decisions in everyday life, we often have to choose between uncertain outcomes. Economic studies have demonstrated that healthy people tend to prefer options with known probabilities (risk) than those with unknown probabilities (ambiguity), which is referred to as "ambiguity aversion." However, it remains unclear how patients with schizophrenia behave under ambiguity, despite growing evidence of their altered decision-making under uncertainty. In this study, combining economic tools and functional magnetic resonance imaging (fMRI), we assessed the attitudes toward risk/ambiguity and investigated the neural correlates during decision-making under risk/ambiguity in schizophrenia. Although no significant difference in attitudes under risk was observed, patients with schizophrenia chose ambiguity significantly more often than the healthy controls. Attitudes under risk and ambiguity did not correlate across patients with schizophrenia. Furthermore, unlike in the healthy controls, activation of the left lateral orbitofrontal cortex was not increased during decision-making under ambiguity compared to under risk in schizophrenia. These results suggest that ambiguity aversion, a well-established subjective bias, is attenuated in patients with schizophrenia, highlighting the need to distinguish between risk and ambiguity when assessing decision-making under these situations. Our findings, comprising important clinical implications, contribute to improved understanding of the mechanisms underlying altered decision-making in patients with schizophrenia. Copyright © 2016 Elsevier B.V. All rights reserved.

  11. Attention and Representational Momentum

    OpenAIRE

    Hayes, Amy; Freyd, Jennifer J

    1995-01-01

    Representational momentum, the tendency for memory to be distorted in the direction of an implied transformation, suggests that dynamics are an intrinsic part of perceptual representations. We examined the effect of attention on dynamic representation by testing for representational momentum under conditions of distraction. Forward memory shifts increase when attention is divided. Attention may be involved in halting but not in maintaining dynamic representations.

  12. Global optimization applied to GPS positioning by ambiguity functions

    International Nuclear Information System (INIS)

    Baselga, Sergio

    2010-01-01

    Differential GPS positioning with carrier-phase observables is commonly done in a process that involves determination of the unknown integer ambiguity values. An alternative approach, named the ambiguity function method, was already proposed in the early days of GPS positioning. By making use of a trigonometric function ambiguity unknowns are eliminated from the functional model before the estimation process. This approach has significant advantages, such as ease of use and insensitivity to cycle slips, but requires such high accuracy in the initial approximate coordinates that its use has been practically dismissed from consideration. In this paper a novel strategy is proposed so that the need for highly accurate initial coordinates disappears: the application of a global optimization method to the ambiguity functions model. The use of this strategy enables the ambiguity function method to compete with the present prevailing approach of ambiguity resolution

  13. Ambiguity, Ambivalence and Extravagance in The Hunger Games

    OpenAIRE

    Oliver, Kelly

    2014-01-01

    I argue that Katniss Everdeen from The Hunger Games is an emblem of what Julia Kristeva calls the “extravagant girl” who wants to have it all and to be the best at everything. Katniss has an ambiguous gender identity, both masculine and feminine, paternal and maternal. And she has ambivalent desires. I conclude that this ambiguity and ambivalence open up new possibilities for girls and initiate an aesthetics of ambiguity.

  14. Ambiguity resolution in systems using Omega for position location

    Science.gov (United States)

    Frenkel, G.; Gan, D. G.

    1974-01-01

    The lane ambiguity problem prevents the utilization of the Omega system for many applications such as locating buoys and balloons. The method of multiple lines of position introduced herein uses signals from four or more Omega stations for ambiguity resolution. The coordinates of the candidate points are determined first through the use of the Newton iterative procedure. Subsequently, a likelihood function is generated for each point, and the ambiguity is resolved by selecting the most likely point. The method was tested through simulation.

  15. Long-Duration Spaceflight Increases Depth Ambiguity of Reversible Perspective Figures

    Science.gov (United States)

    Clément, Gilles; Allaway, Heather C. M.; Demel, Michael; Golemis, Adrianos; Kindrat, Alexandra N.; Melinyshyn, Alexander N.; Merali, Tahir; Thirsk, Robert

    2015-01-01

    The objective of this study was to investigate depth perception in astronauts during and after spaceflight by studying their sensitivity to reversible perspective figures in which two-dimensional images could elicit two possible depth representations. Other ambiguous figures that did not give rise to a perception of illusory depth were used as controls. Six astronauts and 14 subjects were tested in the laboratory during three sessions for evaluating the variability of their responses in normal gravity. The six astronauts were then tested during four sessions while on board the International Space Station for 5–6 months. They were finally tested immediately after return to Earth and up to one week later. The reaction time decreased throughout the sessions, thus indicating a learning effect. However, the time to first percept reversal and the number of reversals were not different in orbit and after the flight compared to before the flight. On Earth, when watching depth-ambiguous perspective figures, all subjects reported seeing one three-dimensional interpretation more often than the other, i.e. a ratio of about 70–30%. In weightlessness this asymmetry gradually disappeared and after 3 months in orbit both interpretations were seen for the same duration. These results indicate that the perception of “illusory” depth is altered in astronauts during spaceflight. This increased depth ambiguity is attributed to the lack of the gravitational reference and the eye-ground elevation for interpreting perspective depth cues. PMID:26146839

  16. Long-Duration Spaceflight Increases Depth Ambiguity of Reversible Perspective Figures.

    Directory of Open Access Journals (Sweden)

    Gilles Clément

    Full Text Available The objective of this study was to investigate depth perception in astronauts during and after spaceflight by studying their sensitivity to reversible perspective figures in which two-dimensional images could elicit two possible depth representations. Other ambiguous figures that did not give rise to a perception of illusory depth were used as controls. Six astronauts and 14 subjects were tested in the laboratory during three sessions for evaluating the variability of their responses in normal gravity. The six astronauts were then tested during four sessions while on board the International Space Station for 5-6 months. They were finally tested immediately after return to Earth and up to one week later. The reaction time decreased throughout the sessions, thus indicating a learning effect. However, the time to first percept reversal and the number of reversals were not different in orbit and after the flight compared to before the flight. On Earth, when watching depth-ambiguous perspective figures, all subjects reported seeing one three-dimensional interpretation more often than the other, i.e. a ratio of about 70-30%. In weightlessness this asymmetry gradually disappeared and after 3 months in orbit both interpretations were seen for the same duration. These results indicate that the perception of "illusory" depth is altered in astronauts during spaceflight. This increased depth ambiguity is attributed to the lack of the gravitational reference and the eye-ground elevation for interpreting perspective depth cues.

  17. Information search and information distortion in the diagnosis of an ambiguous presentation

    Directory of Open Access Journals (Sweden)

    Olga Kostopoulou

    2009-08-01

    Full Text Available Physicians often encounter diagnostic problems with ambiguous and conflicting features. What are they likely to do in such situations? We presented a diagnostic scenario to 84 family physicians and traced their information gathering, diagnoses and management. The scenario contained an ambiguous feature, while the other features supported either a cardiac or a musculoskeletal diagnosis. Due to the risk of death, the cardiac diagnosis should be considered and managed appropriately. Forty-seven participants (56\\% gave only a musculoskeletal diagnosis and 45 of them managed the patient inappropriately (sent him home with painkillers. They elicited less information and spent less time on the scenario than those who diagnosed a cardiac cause. No feedback was provided to participants. Stimulated recall with 52 of the physicians revealed differences in the way that the same information was interpreted as a function of the final diagnosis. The musculoskeletal group denigrated important cues, making them coherent with their representation of a pulled muscle, whilst the cardiac group saw them as evidence for a cardiac problem. Most physicians indicated that they were fairly or very certain about their diagnosis. The observed behaviours can be described as coherence-based reasoning, whereby an emerging judgment influences the evaluation of incoming information, so that confident judgments can be achieved even with ambiguous, uncertain and conflicting information. The role of coherence-based reasoning in medical diagnosis and diagnostic error needs to be systematically examined.

  18. A study of ultraviolet renormalon ambiguities in the determination of $\\alpha_{s}$ from $\\tau$ decay

    CERN Document Server

    Altarelli, Guido; Ridolfi, G; Nason, P; Ridolfi, G

    1995-01-01

    The divergent large-order behaviour of the perturbative series relevant for the determination of \\as from \\tau decay is controlled by the leading ultraviolet (UV) renormalon. Even in the absence of the first infrared (IR) renormalon, an ambiguity of order \\Lambda^2/m_\\tau^2 is introduced. We make a quantitative study of the practical implications of this ambiguity. We discuss the magnitude of UV renormalon corrections obtained in the large-N_f limit, which, although unrealistic, is nevertheless interesting to some extent. We then study a number of improved approximants for the perturbative series, based on a change of variable in the Borel representation, such as to displace the leading UV renormalon singularity at a larger distance from the origin than the first IR renormalon. The spread of the resulting values of \\as(m^2_\\tau) obtained by different approximants, at different renormalization scales, is exhibited as a measure of the underlying ambiguities. Finally, on the basis of mathematical models, we disc...

  19. Finding Home: Landmark Ambiguity in Human Navigation

    Directory of Open Access Journals (Sweden)

    Simon Jetzschke

    2017-07-01

    Full Text Available Memories of places often include landmark cues, i.e., information provided by the spatial arrangement of distinct objects with respect to the target location. To study how humans combine landmark information for navigation, we conducted two experiments: To this end, participants were either provided with auditory landmarks while walking in a large sports hall or with visual landmarks while walking on a virtual-reality treadmill setup. We found that participants cannot reliably locate their home position due to ambiguities in the spatial arrangement when only one or two uniform landmarks provide cues with respect to the target. With three visual landmarks that look alike, the task is solved without ambiguity, while audio landmarks need to play three unique sounds for a similar performance. This reduction in ambiguity through integration of landmark information from 1, 2, and 3 landmarks is well modeled using a probabilistic approach based on maximum likelihood estimation. Unlike any deterministic model of human navigation (based e.g., on distance or angle information, this probabilistic model predicted both the precision and accuracy of the human homing performance. To further examine how landmark cues are integrated we introduced systematic conflicts in the visual landmark configuration between training of the home position and tests of the homing performance. The participants integrated the spatial information from each landmark near-optimally to reduce spatial variability. When the conflict becomes big, this integration breaks down and precision is sacrificed for accuracy. That is, participants return again closer to the home position, because they start ignoring the deviant third landmark. Relying on two instead of three landmarks, however, goes along with responses that are scattered over a larger area, thus leading to higher variability. To model the breakdown of integration with increasing conflict, the probabilistic model based on a

  20. Commonalities and differences in the neural representations of English, Portuguese, and Mandarin sentences: When knowledge of the brain-language mappings for two languages is better than one.

    Science.gov (United States)

    Yang, Ying; Wang, Jing; Bailer, Cyntia; Cherkassky, Vladimir; Just, Marcel Adam

    2017-12-01

    This study extended cross-language semantic decoding (based on a concept's fMRI signature) to the decoding of sentences across three different languages (English, Portuguese and Mandarin). A classifier was trained on either the mapping between words and activation patterns in one language or the mappings in two languages (using an equivalent amount of training data), and then tested on its ability to decode the semantic content of a third language. The model trained on two languages was reliably more accurate than a classifier trained on one language for all three pairs of languages. This two-language advantage was selective to abstract concept domains such as social interactions and mental activity. Representational Similarity Analyses (RSA) of the inter-sentence neural similarities resulted in similar clustering of sentences in all the three languages, indicating a shared neural concept space among languages. These findings identify semantic domains that are common across these three languages versus those that are more language or culture-specific. Copyright © 2017 Elsevier Inc. All rights reserved.

  1. Robust portfolio choice with ambiguity and learning about return predictability

    DEFF Research Database (Denmark)

    Larsen, Linda Sandris; Branger, Nicole; Munk, Claus

    2013-01-01

    We analyze the optimal stock-bond portfolio under both learning and ambiguity aversion. Stock returns are predictable by an observable and an unobservable predictor, and the investor has to learn about the latter. Furthermore, the investor is ambiguity-averse and has a preference for investment...... strategies that are robust to model misspecifications. We derive a closed-form solution for the optimal robust investment strategy. We find that both learning and ambiguity aversion impact the level and structure of the optimal stock investment. Suboptimal strategies resulting either from not learning...... or from not considering ambiguity can lead to economically significant losses....

  2. Hemispheric resource limitations in comprehending ambiguous pictures.

    Science.gov (United States)

    White, H; Minor, S W

    1990-03-01

    Ambiguous pictures (Roschach inkblots) were lateralized for 100 msec vs. 200 msec to the right and left hemispheres (RH and LH) of 32 normal right-handed males who determined which of two previously presented words (an accurate or inaccurate one) better described the inkblot. Over the first 32 trials, subjects receiving each stimulus exposure duration were less accurate when the hemisphere receiving the stimulus also controlled the hand used to register a keypress response (RH-left hand and LH-right hand trials) than when hemispheric resources were shared, i.e., when one hemisphere controlled stimulus processing and the other controlled response programming. These differences were eliminated when the 32 trials were repeated.

  3. Integration, differentiation and ambiguity in safety cultures

    DEFF Research Database (Denmark)

    Richter, Anne; Koch, Christian

    2004-01-01

    This article discusses safety cultures, drawing on the differentiation, integration and ambiguity-scheme introduced by scholars of organizational culture. An ethnographic approach has been applied in the study of meaning and symbols relating to work, hazards, occupational accidents and prevention....... The application of this approach is demonstrated through a multifacetted analysis of safety cultures. Case studies in Danish manufacturing show that it usually is necessary to differentiate between several safety cultures dispersed throughout the shop floor and other parts of the manufacturing organization....... Although some common elements are present across cultures, they are indeed a multiple configuration of cultures. The article illustrates this by providing one case showing a configuration of three cultures, metaphorically labelled Production, Welfare and Master. For example, the former views risk...

  4. Decreasing Ambiguity of the Safety Culture Concept

    International Nuclear Information System (INIS)

    Inoue, Shiichiro; Hosoda, Satoshi; Suganuma, Takashi; Monta, Kazuo; Kameda, Akiyuki

    2001-01-01

    The status of the concept of ''safety culture'' is reviewed. It has not sufficiently taken root. One cause for this is the abstract nature of the concept. Organizations must become aware of the necessity of improving safety and have sufficient power to promote this. The culture of safety must be instilled in each employee, so that each of them will feel responsible for identifying weak points in plant safety. The authors devised a tool for a self-assessment of the safety culture. The tool will bring to light information divides, communication gaps, etc. Recognizing the vulnerabilities of the organization by themselves and discussing these weak points among them is the first step to decrease the ambiguity of the safety culture. The next step is to make these gaps known along with agreed-upon countermeasures. The concept of safety culture will be greatly clarified in this way and lead to safer nuclear power plants

  5. Length Matters: Informational Load in Ambiguity Resolution

    Directory of Open Access Journals (Sweden)

    Barbara Hemforth

    2013-07-01

    Full Text Available In this paper, we will compare prosodic and pragmatic approaches to the role of constituent length in attachment ambiguities. Lengthening a constituent affects its informativity: longer constituents are usually less predictable (Levy & Florian, 2007 and demand a higher processing load than shorter ones (Almor, 1999. Following neo-Gricean accounts (Levinson, 1987 and 1991, increased informational load needs to be justified. This justification is achieved more easily when the long constituent conveys new information and when it relates to central elements of the utterance. Informational load is, however, not a simple question of length in numbers of characters or syllables but more likely a question of amount of information. In three off-line experiments using a cloze task, we will compare the effect of lengthening ambiguous prepositional phrases as in [1a/b/c] either by lengthening a city name or by adding information about the city. We will show that only lengthening by adding information increases attachment to a more central element of the utterance. These results will be discussed based on prosodic and pragmatic factors explaining the role of constituent length for attachment ambiguities.[1] Peter met the doctor of the lawyer from a. Apt. / b. Aix-en-Provence / c. the beautiful city of Apt.Dans cet article, nous comparons une approche prosodique avec une approche pragmatique pour rendre compte des effets de la longueur des constituants dans les ambigüités d’attachement. Augmenter la longueur d’un constituant a des conséquences sur l’information qu’il véhicule : plus un constituant est long et moins il est prédictible (Levy et Florian, 2007 et plus son coût de traitement augmente (Almor, 1999. Suivant les principes néo-gricéens (Levinson, 1987 et 1991, augmenter le poids informationnel doit être justifié. Cette justification est plus facilement satisfaite lorsqu’un constituant long véhicule une information

  6. Gribov ambiguity, perturbation theory, and confinement

    International Nuclear Information System (INIS)

    Greensite, J.P.

    1978-01-01

    The generating functional proposed for gauge theories by Bender, Eguchi, and Pagels (BEP) is shown to be equivalent to a truncated form of the functional integral, in which only one field configuration from each gauge-equivalent Gribov set contributes to the functional integration. The standard perturbation technique provides a method of realizing this truncation condition. It is shown that any gauge-covariant quantity (such as the quark N-point functions), evaluated by perturbating around a field configuration gauge-equivalent to A = 0, is related by a gauge transformation to the same quantity evaluated perturbatively around the trivial vacuum. It follows that, contrary to the conclusion of BEP, the existence of degeneracies in the Coulomb gauge-fixing condition (the Gribov ambiguity) is not directly related to the physics of confinement

  7. Resolving deconvolution ambiguity in gene alternative splicing

    Directory of Open Access Journals (Sweden)

    Hubbell Earl

    2009-08-01

    Full Text Available Abstract Background For many gene structures it is impossible to resolve intensity data uniquely to establish abundances of splice variants. This was empirically noted by Wang et al. in which it was called a "degeneracy problem". The ambiguity results from an ill-posed problem where additional information is needed in order to obtain an unique answer in splice variant deconvolution. Results In this paper, we analyze the situations under which the problem occurs and perform a rigorous mathematical study which gives necessary and sufficient conditions on how many and what type of constraints are needed to resolve all ambiguity. This analysis is generally applicable to matrix models of splice variants. We explore the proposal that probe sequence information may provide sufficient additional constraints to resolve real-world instances. However, probe behavior cannot be predicted with sufficient accuracy by any existing probe sequence model, and so we present a Bayesian framework for estimating variant abundances by incorporating the prediction uncertainty from the micro-model of probe responsiveness into the macro-model of probe intensities. Conclusion The matrix analysis of constraints provides a tool for detecting real-world instances in which additional constraints may be necessary to resolve splice variants. While purely mathematical constraints can be stated without error, real-world constraints may themselves be poorly resolved. Our Bayesian framework provides a generic solution to the problem of uniquely estimating transcript abundances given additional constraints that themselves may be uncertain, such as regression fit to probe sequence models. We demonstrate the efficacy of it by extensive simulations as well as various biological data.

  8. Using Expectancy Theory to quantitatively dissociate the neural representation of motivation from its influential factors in the human brain: An fMRI study.

    Science.gov (United States)

    Kohli, Akshay; Blitzer, David N; Lefco, Ray W; Barter, Joseph W; Haynes, M Ryan; Colalillo, Sam A; Ly, Martina; Zink, Caroline F

    2018-05-08

    Researchers have yet to apply a formal operationalized theory of motivation to neurobiology that would more accurately and precisely define neural activity underlying motivation. We overcome this challenge with the novel application of the Expectancy Theory of Motivation to human fMRI to identify brain activity that explicitly reflects motivation. Expectancy Theory quantitatively describes how individual constructs determine motivation by defining motivation force as the product of three variables: expectancy - belief that effort will better performance; instrumentality - belief that successful performance leads to particular outcome, and valence - outcome desirability. Here, we manipulated information conveyed by reward-predicting cues such that relative cue-evoked activity patterns could be statistically mapped to individual Expectancy Theory variables. The variable associated with activity in any voxel is only reported if it replicated between two groups of healthy participants. We found signals in midbrain, ventral striatum, sensorimotor cortex, and visual cortex that specifically map to motivation itself, rather than other factors. This is important because, for the first time, it empirically clarifies approach motivation neural signals during reward anticipation. It also highlights the effectiveness of the application of Expectancy Theory to neurobiology to more precisely and accurately probe motivation neural correlates than has been achievable previously. Copyright © 2018 Elsevier Inc. All rights reserved.

  9. 13 reasons why the brain is susceptible to oxidative stress

    OpenAIRE

    James Nathan Cobley; Maria Luisa Fiorello; Damian Miles Bailey

    2018-01-01

    The human brain consumes 20% of the total basal oxygen (O2) budget to support ATP intensive neuronal activity. Without sufficient O2 to support ATP demands, neuronal activity fails, such that, even transient ischemia is neurodegenerative. While the essentiality of O2 to brain function is clear, how oxidative stress causes neurodegeneration is ambiguous. Ambiguity exists because many of the reasons why the brain is susceptible to oxidative stress remain obscure. Many are erroneously understood...

  10. Degenerate gauge conditions, generalized Gribov's ambiguity and BRST symmetry

    International Nuclear Information System (INIS)

    Fabbrichesi, M.E.

    1987-01-01

    The BFS-BRST approach to gauge theories is considered. It is argued that the BRST-invariant boundary conditions ordinarily used do not maintain the necessary degeneracy in the gauge fixing. As a by-product of this discussion, the existence of a generalized Gribov-like ambiguity is suggested. This ambiguity is however shown to be just a particular BRST transformation

  11. Examining English-German Translation Ambiguity Using Primed Translation Recognition

    Science.gov (United States)

    Eddington, Chelsea M.; Tokowicz, Natasha

    2013-01-01

    Many words have more than one translation across languages. Such "translation-ambiguous" words are translated more slowly and less accurately than their unambiguous counterparts. We examine the extent to which word context and translation dominance influence the processing of translation-ambiguous words. We further examine how these factors…

  12. Top-Down Influence in Young Children's Linguistic Ambiguity Resolution

    Science.gov (United States)

    Rabagliati, Hugh; Pylkkanen, Liina; Marcus, Gary F.

    2013-01-01

    Language is rife with ambiguity. Do children and adults meet this challenge in similar ways? Recent work suggests that while adults resolve syntactic ambiguities by integrating a variety of cues, children are less sensitive to top-down evidence. We test whether this top-down insensitivity is specific to syntax or a general feature of children's…

  13. Children's Comprehension of Two Types of Syntactic Ambiguity

    Science.gov (United States)

    Zimmer, Elly Jane

    2017-01-01

    This study asks whether children accept both interpretations of ambiguous sentences with contexts supporting each option. Twenty-six 3- to 5-year-old English-speaking children and a control group of 30 English-speaking adults participated in a truth value judgment task. As a step towards evaluating the complexity of syntactic ambiguity, the…

  14. On ambiguities in the exponentiation of large QCD perturbative corrections

    International Nuclear Information System (INIS)

    Chyla, Jiri

    1986-01-01

    Ambiguities and some practical questions connected with the exponentiation of higher-order QCD perturbative corrections are discussed for the case of deep inelastic lepton-hadron scattering in the non-singlet channel. The importance of still higher-order calculations for resolving these ambiguities is stressed. (author)

  15. Discriminating Between Models of Ambiguity Attitude : A Qualitative Test

    NARCIS (Netherlands)

    Cubitt, Robin; van de Kuilen, Gijs; Mukerji, Sujoy

    The exchange between Epstein (2010) and Klibanoff et al. (2012) identified a behavioral issue that sharply distinguishes between two classes of models of ambiguity sensitivity, exemplified by the 훼- MEU model and the smooth ambiguity model, respectively. The issue in question is whether a subject’s

  16. U.S./Arab Reflections on Our Tolerance for Ambiguity

    Science.gov (United States)

    Bright, Larry K.; Mahdi, Ghada S.

    2012-01-01

    As the authors, a Midwestern American educational administration professor and a Middle Eastern Iraqi doctoral candidate, have continued to interact over the past 3 years, both have come to appreciate the importance of increasing their tolerance for ambiguity--ambiguities in examining cultural, linguistic, and religious customs and complexities in…

  17. The Learning Teacher: Role of Ambiguity in Education

    Science.gov (United States)

    Suzawa, Gilbert S.

    2013-01-01

    Life is full of ambiguities, but as teachers we generally try to teach our students in a manner that sanitizes knowledge of all of its ambiguities. In doing so, we create an educational environment which forces students to learn in a rather meaningless fashion and this in turn leads to a lack of vitality and relevance within the academy. This need…

  18. Ambiguity Tolerance and Perceptual Learning Styles of Chinese EFL Learners

    Science.gov (United States)

    Li, Haishan; He, Qingshun

    2016-01-01

    Ambiguity tolerance and perceptual learning styles are the two influential elements showing individual differences in EFL learning. This research is intended to explore the relationship between Chinese EFL learners' ambiguity tolerance and their preferred perceptual learning styles. The findings include (1) the learners are sensitive to English…

  19. Cognitive Flexibility Supports Preschoolers' Detection of Communicative Ambiguity

    Science.gov (United States)

    Gillis, Randall; Nilsen, Elizabeth S.

    2014-01-01

    To become successful communicators, children must be sensitive to the clarity/ambiguity of language. Significant gains in children's ability to detect communicative ambiguity occur during the early school-age years. However, little is known about the cognitive abilities that support this development. Relations between cognitive flexibility and…

  20. Ambiguity in Speaking Chemistry and Other STEM Content: Educational Implications

    Science.gov (United States)

    Isaacson, Mick D.; Michaels, Michelle

    2015-01-01

    Ambiguity in speech is a possible barrier to the acquisition of knowledge for students who have print disabilities (such as blindness, visual impairments, and some specific learning disabilities) and rely on auditory input for learning. Chemistry appears to have considerable potential for being spoken ambiguously and may be a barrier to accessing…

  1. Quantization ambiguity and the Aharanov-Bohm effect

    International Nuclear Information System (INIS)

    Kunstatter, G.

    1983-01-01

    A brief review is given of the role of quantization ambiguity in both quantum mechanics and quantum field theory. The author points out that quantization ambiguity is not relevant to discussions of physical experiments designed to test the Aharanov-Bohm effect. A recent proposal for such an experiment involving Aharanov-Bohm currents in thin superconducting cylinders is mentioned. (Auth.)

  2. High energy collisions and the proton structure: an ambiguity

    International Nuclear Information System (INIS)

    Franca, H.M.

    1980-01-01

    It is pointed out an ambiguity in the determination of the sign of the imaginary part of the proton-proton elastic-scattering amplitude for ]t]>]t min . Some implications of such and ambiguity concerning the proton structure are discussed and finally, an experimental analysis which could solve it is suggested. (L.C.) [pt

  3. Inevitable ambiguity in perturbation around flat space-time

    International Nuclear Information System (INIS)

    Ichinose, S.; Kaminaga, Y.

    1989-01-01

    Perturbation of general-relativistic predictions around flat geometry, in general, introduces inevitable ambiguity. The ambiguity reflects the geometrical nature of general relativity and is never a difficulty of it. We explain it by taking a concrete example of the radar-echo experiment

  4. Effective potential for bilocal composite fields and its ambiguity

    International Nuclear Information System (INIS)

    Muta, T.

    1988-01-01

    It is discussed that an ambiguity exists in the definition of the effective potential for bilocal composite fields which is an indispensable tool to discuss dynamical symmetry breaking. The ambiguity gives warning to arguments on the stability of ground states based on the curvature of the effective potential

  5. Children's Understanding of Ambiguous Idioms and Conversational Perspective-Taking

    Science.gov (United States)

    Le Sourn-Bissaoui, Sandrine; Caillies, Stephanie; Bernard, Stephane; Deleau, Michel; Brule, Lauriane

    2012-01-01

    The aim of this study was to test the hypothesis that conversational perspective-taking is a determinant of unfamiliar ambiguous idiom comprehension. We investigated two types of ambiguous idiom, decomposable and nondecomposable expressions, which differ in the degree to which the literal meanings of the individual words contribute to the overall…

  6. Quantification Scope Ambiguity Resolution: Evidence from Persian and English

    Science.gov (United States)

    Asadollahfam, Hassan; Lotfi, Ahmad Reza

    2010-01-01

    This study investigates the interpretation of scopally ambiguous sentences containing noun phrases with double quantified constituents from a processing perspective. The questions this study tried to answer were: whether or not the preferred interpretation for doubly quantified ambiguous sentences in English was influenced by English learners' L1…

  7. Ambiguous sets of partial wave amplitudes can intersect

    International Nuclear Information System (INIS)

    Kok, L.P.; Roo, M. de

    1976-01-01

    Continuation in energy as a method to resolve ambiguities in phase-shift analysis is discussed. It is shown that continuity in energy is not in all cases sufficient to resolve ambiguities, and examples are given of such cases for both spin 0 - spin 0 and spin 0 - spin 1/2 scattering. (author)

  8. Ambiguity and Nominal Group Multiple Post modification in the ...

    African Journals Online (AJOL)

    Administrator

    students of The Federal Polytechnic, Ede, Nigeria offering. English courses as .... “a piece of land along a river” or “a place for keeping money and valuables”. ... ambiguity. Attachment ambiguity occurs when a modifier may be logically or ...

  9. Surgical aspects of ambiguous genitalia associated with congenital ...

    African Journals Online (AJOL)

    Aim The aim of the study was to review the current approach to manage ambiguous genitalia caused by CAH. Methods This was a retrospective study of 30 patientswith CAH and ambiguous genitalia treated over 10 years. Age at presentation, degree of verilization, preoperative diagnostic studies, operative technique, ...

  10. Neural imaginaries and clinical epistemology: Rhetorically mapping the adolescent brain in the clinical encounter.

    Science.gov (United States)

    Buchbinder, Mara

    2015-10-01

    The social work of brain images has taken center stage in recent theorizing of the intersections between neuroscience and society. However, neuroimaging is only one of the discursive modes through which public representations of neurobiology travel. This article adopts an expanded view toward the social implications of neuroscientific thinking to examine how neural imaginaries are constructed in the absence of visual evidence. Drawing on ethnographic fieldwork conducted over 18 months (2008-2009) in a United States multidisciplinary pediatric pain clinic, I examine the pragmatic clinical work undertaken to represent ambiguous symptoms in neurobiological form. Focusing on one physician, I illustrate how, by rhetorically mapping the brain as a therapeutic tool, she engaged in a distinctive form of representation that I call neural imagining. In shifting my focus away from the purely material dimensions of brain images, I juxtapose the cultural work of brain scanning technologies with clinical neural imaginaries in which the teenage brain becomes a space of possibility, not to map things as they are, but rather, things as we hope they might be. These neural imaginaries rely upon a distinctive clinical epistemology that privileges the creative work of the imagination over visualization technologies in revealing the truths of the body. By creating a therapeutic space for adolescents to exercise their imaginative faculties and a discursive template for doing so, neural imagining relocates adolescents' agency with respect to epistemologies of bodily knowledge and the role of visualization practices therein. In doing so, it provides a more hopeful alternative to the dominant popular and scientific representations of the teenage brain that view it primarily through the lens of pathology. Copyright © 2014 Elsevier Ltd. All rights reserved.

  11. Updating impairments and the failure to explore new hypotheses following right brain damage.

    Science.gov (United States)

    Stöttinger, Elisabeth; Guay, Carolyn Louise; Danckert, James; Anderson, Britt

    2018-06-01

    We have shown recently that damage to the right hemisphere impairs the ability to update mental models when evidence suggests an old model is no longer appropriate. We argue that this deficit is generic in the sense that it crosses multiple cognitive and perceptual domains. Here, we examined the nature of this updating impairment to determine more precisely the underlying mechanisms. We had right (RBD, N = 12) and left brain damaged (LBD, N = 10) patients perform versions of our picture-morphing task in which pictures gradually morph from one object (e.g., shark) to another (e.g., plane). Performance was contrasted against two groups of healthy older controls, one matched on age (HCO-age-matched, N = 9) and another matched on general level of cognitive ability (HCO-cognitively-matched, N = 9). We replicated our earlier findings showing that RBD patients took longer than LBD patients and HCOs to report seeing the second object in a sequence of morphing images. The groups did not differ when exposed to a morphing sequence a second time, or when responding to ambiguous images outside the morphing context. This indicates that RBD patients have little difficulty alternating between known representations or labeling ambiguous images. Instead, the difficulty lies in generating alternate hypotheses for ambiguous information. Lesion overlay analyses, although speculative given the sample size, are consistent with our fMRI work in healthy individuals in implicating the anterior insular cortex as critical for updating mental models.

  12. Context-dependent lexical ambiguity resolution: MEG evidence for the time-course of activity in left inferior frontal gyrus and posterior middle temporal gyrus.

    Science.gov (United States)

    Mollo, Giovanna; Jefferies, Elizabeth; Cornelissen, Piers; Gennari, Silvia P

    An MEG study investigated the role of context in semantic interpretation by examining the comprehension of ambiguous words in contexts leading to different interpretations. We compared high-ambiguity words in minimally different contexts (to bowl, the bowl) to low-ambiguity counterparts (the tray, to flog). Whole brain beamforming revealed the engagement of left inferior frontal gyrus (LIFG) and posterior middle temporal gyrus (LPMTG). Points of interest analyses showed that both these sites showed a stronger response to verb-contexts by 200 ms post-stimulus and displayed overlapping ambiguity effects that were sustained from 300 ms onwards. The effect of context was stronger for high-ambiguity words than for low-ambiguity words at several different time points, including within the first 100 ms post-stimulus. Unlike LIFG, LPMTG also showed stronger responses to verb than noun contexts in low-ambiguity trials. We argue that different functional roles previously attributed to LIFG and LPMTG are in fact played out at different periods during processing. Crown Copyright © 2018. Published by Elsevier Inc. All rights reserved.

  13. Modulating the Activity of the DLPFC and OFC Has Distinct Effects on Risk and Ambiguity Decision-Making: A tDCS Study.

    Science.gov (United States)

    Yang, Xiaolan; Gao, Mei; Shi, Jinchuan; Ye, Hang; Chen, Shu

    2017-01-01

    Human beings are constantly exposed to two types of uncertainty situations, risk and ambiguity. Neuroscientific studies suggest that the dorsolateral prefrontal cortex (DLPFC) and the orbital frontal cortex (OFC) play significant roles in human decision making under uncertainty. We applied the transcranial direct current stimulation (tDCS) device to modulate the activity of participants' DLPFC and OFC separately, comparing the causal relationships between people's behaviors and the activity of the corresponding brain cortex when confronted with situations of risk and ambiguity. Our experiment employed a pre-post design and a risk/ambiguity decision-making task, from which we could calculate the preferences via an estimation model. We found evidences that modulating the activity of the DLPFC using right anodal/left cathodal tDCS significantly enhanced the participants' preferences for risk, whereas modulating the activity of the OFC with right anodal/left cathodal tDCS significantly decreased the participants' preferences for ambiguity. The reverse effects were also observed in the reversed tDCS treatments on the two areas. Our results suggest that decision-making processes under risk and ambiguity are complicated and may be encoded in two distinct circuits in our brains as the DLPFC primarily impacts decisions under risk whereas the OFC affects ambiguity.

  14. Modulating the Activity of the DLPFC and OFC Has Distinct Effects on Risk and Ambiguity Decision-Making: A tDCS Study

    Directory of Open Access Journals (Sweden)

    Xiaolan Yang

    2017-08-01

    Full Text Available Human beings are constantly exposed to two types of uncertainty situations, risk and ambiguity. Neuroscientific studies suggest that the dorsolateral prefrontal cortex (DLPFC and the orbital frontal cortex (OFC play significant roles in human decision making under uncertainty. We applied the transcranial direct current stimulation (tDCS device to modulate the activity of participants’ DLPFC and OFC separately, comparing the causal relationships between people’s behaviors and the activity of the corresponding brain cortex when confronted with situations of risk and ambiguity. Our experiment employed a pre–post design and a risk/ambiguity decision-making task, from which we could calculate the preferences via an estimation model. We found evidences that modulating the activity of the DLPFC using right anodal/left cathodal tDCS significantly enhanced the participants’ preferences for risk, whereas modulating the activity of the OFC with right anodal/left cathodal tDCS significantly decreased the participants’ preferences for ambiguity. The reverse effects were also observed in the reversed tDCS treatments on the two areas. Our results suggest that decision-making processes under risk and ambiguity are complicated and may be encoded in two distinct circuits in our brains as the DLPFC primarily impacts decisions under risk whereas the OFC affects ambiguity.

  15. Ambiguity aversion and household portfolio choice puzzles: Empirical evidence.

    Science.gov (United States)

    Dimmock, Stephen G; Kouwenberg, Roy; Mitchell, Olivia S; Peijnenburg, Kim

    2016-03-01

    We test the relation between ambiguity aversion and five household portfolio choice puzzles: nonparticipation in equities, low allocations to equity, home-bias, own-company stock ownership, and portfolio under-diversification. In a representative US household survey, we measure ambiguity preferences using custom-designed questions based on Ellsberg urns. As theory predicts, ambiguity aversion is negatively associated with stock market participation, the fraction of financial assets in stocks, and foreign stock ownership, but it is positively related to own-company stock ownership. Conditional on stock ownership, ambiguity aversion is related to portfolio under-diversification, and during the financial crisis, ambiguity-averse respondents were more likely to sell stocks.

  16. Ambiguity aversion and household portfolio choice puzzles: Empirical evidence*

    Science.gov (United States)

    Dimmock, Stephen G.; Kouwenberg, Roy; Mitchell, Olivia S.; Peijnenburg, Kim

    2017-01-01

    We test the relation between ambiguity aversion and five household portfolio choice puzzles: nonparticipation in equities, low allocations to equity, home-bias, own-company stock ownership, and portfolio under-diversification. In a representative US household survey, we measure ambiguity preferences using custom-designed questions based on Ellsberg urns. As theory predicts, ambiguity aversion is negatively associated with stock market participation, the fraction of financial assets in stocks, and foreign stock ownership, but it is positively related to own-company stock ownership. Conditional on stock ownership, ambiguity aversion is related to portfolio under-diversification, and during the financial crisis, ambiguity-averse respondents were more likely to sell stocks. PMID:28458446

  17. Semantic Ambiguity Effects in L2 Word Recognition.

    Science.gov (United States)

    Ishida, Tomomi

    2018-06-01

    The present study examined the ambiguity effects in second language (L2) word recognition. Previous studies on first language (L1) lexical processing have observed that ambiguous words are recognized faster and more accurately than unambiguous words on lexical decision tasks. In this research, L1 and L2 speakers of English were asked whether a letter string on a computer screen was an English word or not. An ambiguity advantage was found for both groups and greater ambiguity effects were found for the non-native speaker group when compared to the native speaker group. The findings imply that the larger ambiguity advantage for L2 processing is due to their slower response time in producing adequate feedback activation from the semantic level to the orthographic level.

  18. Concept analysis: Role ambiguity in senior nursing students.

    Science.gov (United States)

    Kalkman, Beth

    2018-04-01

    Role ambiguity is a lack of clarity or uncertainty related to one's position or role. Role ambiguity has been documented in the literature in relationship to athletics, industry, business, education, and nursing. However, a concept analysis has not been performed. Therefore, the process of concept analysis outlined by Walker and Avant is now used to look at the concept of role ambiguity and its relevance to senior nursing students' socialization and education into the profession of nursing. Attributes, antecedents, consequences, and empiric referents are discussed and theories commonly associated with role ambiguity are presented. At the end of the analysis, an operational definition is provided for use in exploring the concept of role ambiguity as it relates to senior nursing students' articulation of the role of the professional nurse. © 2017 Wiley Periodicals, Inc.

  19. Ambiguities in the reaction mechanism for (e,e'N)

    International Nuclear Information System (INIS)

    Forest, T. de Jr.

    1984-01-01

    The primary motivation for performing quasi-elastic (e,e'N) experiments revolves around the plane wave impulse approximation (PWIA) description of this reaction. Since the PWIA is an approximation, corrections are necessary in practice in order to extract the desired nuclear structure. Unless one understands the physics behind these corrections this introduces ambiguities. In fact the PWIA itself is an ambiguous prescription since a 'free' off-shell cross section is not a well-defined concept. It is these ambiguities which are discussed in this talk. Most of the paper is devoted to the ambiguities associated with the electromagnetic interaction. The author concentrates on four topics: (1) the interaction of the electron with the nucleus in general; (2) ambiguities in the application of the impulse approximation; (3) the sigma-omega model; and (4) the Coulomb sum rule. (Auth.)

  20. Intolerance for approach of ambiguity in social anxiety disorder.

    Science.gov (United States)

    Kuckertz, Jennie M; Strege, Marlene V; Amir, Nader

    2017-06-01

    Previous research has utilised the approach-avoidance task (AAT) to measure approach and avoidance action tendencies in socially anxious individuals. "Neutral" social stimuli may be perceived as ambiguous and hence threatening to socially anxious individuals, however it is unclear whether this results in difficulty approaching ambiguous ("neutral") versus unambiguous threat (e.g. disgust) faces (i.e. intolerance of ambiguity). Thirty participants with social anxiety disorder (SADs) and 29 non-anxious controls completed an implicit AAT in which they were instructed to approach or avoid neutral and disgust faces (i.e. pull or push a joystick) based on colour of the picture border. Results indicated that SADs demonstrated greater difficulty approaching neutral relative to disgust faces. Moreover, intolerance for approach of ambiguity predicted social anxiety severity while controlling for the effects of trait anxiety and depression. Our results provide further support for the role of intolerance of ambiguity in SAD.

  1. Absence of the Gribov ambiguity in a quadratic gauge

    International Nuclear Information System (INIS)

    Raval, Haresh

    2016-01-01

    The Gribov ambiguity exists in various gauges. Algebraic gauges are likely to be ambiguity free. However, algebraic gauges are not Lorentz invariant, which is their fundamental flaw. In addition, they are not generally compatible with the boundary conditions on the gauge fields, which are needed to compactify the space i.e., the ambiguity continues to exist on a compact manifold. Here we discuss a quadratic gauge fixing, which is Lorentz invariant. We consider an example of a spherically symmetric gauge field configuration in which we prove that this Lorentz invariant gauge removes the ambiguity on a compact manifold S 3 , when a proper boundary condition on the gauge configuration is taken into account. Thus, we provide one example where the ambiguity is absent on a compact manifold in the algebraic gauge. We also show that the BRST invariance is preserved in this gauge. (orig.)

  2. Absence of the Gribov ambiguity in a quadratic gauge

    Energy Technology Data Exchange (ETDEWEB)

    Raval, Haresh [Indian Institute of Technology, Bombay, Department of Physics, Mumbai (India)

    2016-05-15

    The Gribov ambiguity exists in various gauges. Algebraic gauges are likely to be ambiguity free. However, algebraic gauges are not Lorentz invariant, which is their fundamental flaw. In addition, they are not generally compatible with the boundary conditions on the gauge fields, which are needed to compactify the space i.e., the ambiguity continues to exist on a compact manifold. Here we discuss a quadratic gauge fixing, which is Lorentz invariant. We consider an example of a spherically symmetric gauge field configuration in which we prove that this Lorentz invariant gauge removes the ambiguity on a compact manifold S{sup 3}, when a proper boundary condition on the gauge configuration is taken into account. Thus, we provide one example where the ambiguity is absent on a compact manifold in the algebraic gauge. We also show that the BRST invariance is preserved in this gauge. (orig.)

  3. Azimuth Phase Coding for Range Ambiguity Suppression in SAR

    DEFF Research Database (Denmark)

    Dall, Jørgen; Kusk, Anders

    2004-01-01

    A novel ambiguity suppression technique is proposed. Range ambiguities in synthetic aperture radar (SAR) images are eliminated with an azimuth filter after having applied an azimuth phase modulation to the transmitted pulses and a corresponding demodulation to the received pulses. The technique...... excels by actually eliminating the ambiguities rather than just defocusing them as most other techniques do. This makes the proposed technique applicable to distributed targets. The range ambiguity suppression permits the pulse repetition frequency (PRF) to exceed the upper limit otherwise defined...... by the antenna elevation dimension. The fundamental antenna area constraint still applies, but the PRF can be chosen with more freedom. In addition to ambiguity suppression, potential applications include nadir return elimination and signal-to-noise ratio improvement....

  4. Coding of level of ambiguity within neural systems mediating choice.

    Science.gov (United States)

    Lopez-Paniagua, Dan; Seger, Carol A

    2013-01-01

    Data from previous neuroimaging studies exploring neural activity associated with uncertainty suggest varying levels of activation associated with changing degrees of uncertainty in neural regions that mediate choice behavior. The present study used a novel task that parametrically controlled the amount of information hidden from the subject; levels of uncertainty ranged from full ambiguity (no information about probability of winning) through multiple levels of partial ambiguity, to a condition of risk only (zero ambiguity with full knowledge of the probability of winning). A parametric analysis compared a linear model in which weighting increased as a function of level of ambiguity, and an inverted-U quadratic models in which partial ambiguity conditions were weighted most heavily. Overall we found that risk and all levels of ambiguity recruited a common "fronto-parietal-striatal" network including regions within the dorsolateral prefrontal cortex, intraparietal sulcus, and dorsal striatum. Activation was greatest across these regions and additional anterior and superior prefrontal regions for the quadratic function which most heavily weighs trials with partial ambiguity. These results suggest that the neural regions involved in decision processes do not merely track the absolute degree ambiguity or type of uncertainty (risk vs. ambiguity). Instead, recruitment of prefrontal regions may result from greater degree of difficulty in conditions of partial ambiguity: when information regarding reward probabilities important for decision making is hidden or not easily obtained the subject must engage in a search for tractable information. Additionally, this study identified regions of activity related to the valuation of potential gains associated with stimuli or options (including the orbitofrontal and medial prefrontal cortices and dorsal striatum) and related to winning (including orbitofrontal cortex and ventral striatum).

  5. The Ethics of Strategic Ambiguity: Contrasting Teleologically and Deontologically Based Experiences.

    Science.gov (United States)

    Paul, Jim; And Others

    This paper describes ethical considerations in the use of strategic ambiguity in organizational communication. Ambiguity is defined as "experienced ambiguity" and is distinct from uncertainty and equivocality which are properties of a stimulus. Strategic ambiguity is the use of "calculated ambiguity" in organizations to achieve…

  6. Ambiguous Loss in a Non-Western Context: Families of the Disappeared in Postconflict Nepal

    Science.gov (United States)

    Robins, Simon

    2010-01-01

    Ambiguous loss has become a standard theory for understanding the impact of situations where the presence of a family member is subject to ambiguity. A number of studies of ambiguous loss have been made in a range of situations of ambiguity, but almost all have been firmly located within a Western cultural context. Here, ambiguous loss is explored…

  7. Factorizations and physical representations

    International Nuclear Information System (INIS)

    Revzen, M; Khanna, F C; Mann, A; Zak, J

    2006-01-01

    A Hilbert space in M dimensions is shown explicitly to accommodate representations that reflect the decomposition of M into prime numbers. Representations that exhibit the factorization of M into two relatively prime numbers: the kq representation (Zak J 1970 Phys. Today 23 51), and related representations termed q 1 q 2 representations (together with their conjugates) are analysed, as well as a representation that exhibits the complete factorization of M. In this latter representation each quantum number varies in a subspace that is associated with one of the prime numbers that make up M

  8. Spectral fingerprints of large-scale cortical dynamics during ambiguous motion perception.

    Science.gov (United States)

    Helfrich, Randolph F; Knepper, Hannah; Nolte, Guido; Sengelmann, Malte; König, Peter; Schneider, Till R; Engel, Andreas K

    2016-11-01

    Ambiguous stimuli have been widely used to study the neuronal correlates of consciousness. Recently, it has been suggested that conscious perception might arise from the dynamic interplay of functionally specialized but widely distributed cortical areas. While previous research mainly focused on phase coupling as a correlate of cortical communication, more recent findings indicated that additional coupling modes might coexist and possibly subserve distinct cortical functions. Here, we studied two coupling modes, namely phase and envelope coupling, which might differ in their origins, putative functions and dynamics. Therefore, we recorded 128-channel EEG while participants performed a bistable motion task and utilized state-of-the-art source-space connectivity analysis techniques to study the functional relevance of different coupling modes for cortical communication. Our results indicate that gamma-band phase coupling in extrastriate visual cortex might mediate the integration of visual tokens into a moving stimulus during ambiguous visual stimulation. Furthermore, our results suggest that long-range fronto-occipital gamma-band envelope coupling sustains the horizontal percept during ambiguous motion perception. Additionally, our results support the idea that local parieto-occipital alpha-band phase coupling controls the inter-hemispheric information transfer. These findings provide correlative evidence for the notion that synchronized oscillatory brain activity reflects the processing of sensory input as well as the information integration across several spatiotemporal scales. The results indicate that distinct coupling modes are involved in different cortical computations and that the rich spatiotemporal correlation structure of the brain might constitute the functional architecture for cortical processing and specific multi-site communication. Hum Brain Mapp 37:4099-4111, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  9. Ambiguity resolution for satellite Doppler positioning systems

    Science.gov (United States)

    Argentiero, P.; Marini, J.

    1979-01-01

    The implementation of satellite-based Doppler positioning systems frequently requires the recovery of transmitter position from a single pass of Doppler data. The least-squares approach to the problem yields conjugate solutions on either side of the satellite subtrack. It is important to develop a procedure for choosing the proper solution which is correct in a high percentage of cases. A test for ambiguity resolution which is the most powerful in the sense that it maximizes the probability of a correct decision is derived. When systematic error sources are properly included in the least-squares reduction process to yield an optimal solution the test reduces to choosing the solution which provides the smaller valuation of the least-squares loss function. When systematic error sources are ignored in the least-squares reduction, the most powerful test is a quadratic form comparison with the weighting matrix of the quadratic form obtained by computing the pseudoinverse of a reduced-rank square matrix. A formula for computing the power of the most powerful test is provided. Numerical examples are included in which the power of the test is computed for situations that are relevant to the design of a satellite-aided search and rescue system.

  10. X-Linked Lissencephaly with Absent Corpus Callosum and Ambiguous Genitalia: A Case Report

    Directory of Open Access Journals (Sweden)

    Alireza Jashni Motlagh

    2016-03-01

    Case presentation: The patient was a one-day-old term neonate admitted to our neonatal intensive care unit due to refractory seizure. He was the second child of the family, born to non-consanguineous and healthy parents. His midface was slightly hypoplastic with long and smooth philtrum; the neonate had ambiguous genitalia, as well. Hormonal investigation demonstrated elevated serum 17OH-progesterone, dehydroepiandrosterone sulfate, and testosterone levels. Chromosomal analysis showed a normal male karyotype (46, XY. Brain computed tomography scan showed a typical pattern of lissencephaly with a posterior-to-anterior gradient of severity consisting of frontal pachygyria, posterior agyria, and absence of corpus collosum

  11. Memory cueing during sleep modifies the interpretation of ambiguous scenes in adolescents and adults

    Directory of Open Access Journals (Sweden)

    Sabine Groch

    2016-02-01

    Full Text Available The individual tendency to interpret ambiguous situations negatively is associated with mental disorders. Interpretation biases are already evident during adolescence and due to the greater plasticity of the developing brain it may be easier to change biases during this time. We investigated in healthy adolescents and adults whether stabilizing memories of positive or negative scenes modulates the later interpretation of similar scenes. In the evening, participants learnt associations between ambiguous pictures and words that disambiguate the valence of the pictures in a positive or negative direction. Half of the words were acoustically presented (i.e. cued during post-learning sleep which is known to benefit memory consolidation by inducing reactivation of learned information. Cued compared to un-cued stimuli were remembered better the next morning. Importantly, cueing positively disambiguated pictures resulted in more positive interpretations whereas cueing negatively disambiguated pictures led to less positive interpretations of new ambiguous pictures with similar contents the next morning. These effects were not modulated by participants’ age indicating that memory cueing was as efficient in adolescents as in adults. Our findings suggest that memory cueing during sleep can modify interpretation biases by benefitting memory stabilization and generalization. Implications for clinical settings are discussed.

  12. David Ferrier: brain drawings and brain maps.

    Science.gov (United States)

    Lazar, J Wayne

    2013-01-01

    This chapter has two emphases, one is about the men who influenced the visual representations that David Ferrier (1843-1928) used to illustrate his work on localization of brain functions during the years 1873-1875, namely, Alexander Ecker, John C. Galton, and Ernest Waterlow, and the other is about the nature of medical representations and of Ferrier's illustrations in particular. Medical illustrations are characterized either as pictures, line drawings, or brain maps. Ferrier's illustrations will be shown to be increasingly sophisticated brain maps that contrast with early nineteenth-century standards of medical illustrations, as exemplified by John Bell (1763-1829). © 2013 Elsevier B.V. All rights reserved.

  13. Semi-classical analysis of optical model ambiguities

    International Nuclear Information System (INIS)

    Cuer, M.

    1979-01-01

    The ambiguities in the inverse problem at fixed energy in quantum mechanics are analyzed in the framework of the JWKB method. When the classical turning point is unique for all values of the impact parameter (high energies region), the ambiguities proceed only from the quantization of the angular momentum. In the asymptotic region the difference between two particular equivalent potentials changes sign infinitely often. In addition, the set of equivalent potentials which have a given asymptotic form is bounded (except perhaps at the origin). When there are several turning points for small values of the impact parameter (low-energy region), new ambiguities arise from the fact that the parts of the potential that are located between turning points are not ''visible'' in the classical limit. The set of equivalent potentials wich have a given asymptotic form is then not bounded. Mumerical examples (of real and complex equivalent potentials) are given. The optical model ambiguities are studied. The potential depth ambiguities also appear in classical mechanics, but their discrete nature is a quantum property. The VR/sup p//sup( V/)=constant ambiguities can be explained by the quantum corrections to the spiral scattering phenomenon. An attempt to explain why ambiguities arise only with heavy particles scattering is also given

  14. Gauge ambiguities in (rvec e,e'rvec N) reactions

    International Nuclear Information System (INIS)

    Kelly, J.J.

    1997-01-01

    We examine the sensitivity of the distorted-wave impulse approximation for single-nucleon electromagnetic knockout from valence orbitals to ambiguities in the one-body current operator. Violations of current conservation are classified as gauge ambiguities, whereas the elements of a particular class of structural differences off shell are labeled Gordon ambiguities. Gauge ambiguities in differential cross sections and longitudinal response functions are found to increase with missing momentum and to become particularly severe for low-Q 2 kinematical conditions that are far from quasifree but are sometimes used to investigate correlations. The azimuthal asymmetry may provide a useful experimental means for selecting a gauge. Gordon ambiguities increase with Q 2 and are larger for relativistic than for nonrelativistic approaches. Because ambiguities in the one-body current are at least as large as effects due to correlations and there are additional uncertainties due to two-body currents, final-state interactions, and relativistic distortion, we conclude that is unlikely that information about correlations can be extracted from single-nucleon knockout from valence orbitals at large missing momentum. On the other hand, gauge and Gordon ambiguities and uncertainties in final-state interactions have very little effect upon the helicity-dependent recoil polarization, which can be used to investigate the roles of two-body currents and/or possible medium modifications of the one-body current. copyright 1997 The American Physical Society

  15. Comparing Tolerance of Ambiguity in Veterinary and Medical Students.

    Science.gov (United States)

    Hancock, Jason; Hammond, Jennifer A; Roberts, Martin; Mattick, Karen

    Current guidelines suggest that educators in both medical and veterinary professions should do more to ensure that students can tolerate ambiguity. Designing curricula to achieve this requires the ability to measure and understand differences in ambiguity tolerance among and within professional groups. Although scales have been developed to measure tolerance of ambiguity in both medical and veterinary professions, no comparative studies have been reported. We compared the tolerance of ambiguity of medical and veterinary students, hypothesizing that veterinary students would have higher tolerance of ambiguity, given the greater patient diversity and less well-established evidence base underpinning practice. We conducted a secondary analysis of questionnaire data from first- to fourth-year medical and veterinary students. Tolerance of ambiguity scores were calculated and compared using the TAMSAD scale (29 items validated for the medical student population), the TAVS scale (27 items validated for the veterinary student population), and a scale comprising the 22 items common to both scales. Using the TAMSAD and TAVS scales, medical students had a significantly higher mean tolerance of ambiguity score than veterinary students (56.1 vs. 54.1, pambiguity than veterinary students, although this depends on the scale used.

  16. Reading comprehension of ambiguous sentences by school-age children with autism spectrum disorder.

    Science.gov (United States)

    Davidson, Meghan M; Ellis Weismer, Susan

    2017-12-01

    Weak central coherence (processing details over gist), poor oral language abilities, poor suppression, semantic interference, and poor comprehension monitoring have all been implicated to affect reading comprehension in individuals with autism spectrum disorder (ASD). This study viewed the contributions of different supporting skills as a collective set of skills necessary for context integration-a multi-component view-to examine individual differences in reading comprehension in school-age children (8-14 years) with ASD (n = 23) and typically developing control peers (n = 23). Participants completed a written ambiguous sentence comprehension task in which participants had to integrate context to determine the correct homonym meaning via picture selection. Both comprehension products (i.e., offline representations after reading) and processes (i.e., online processing during reading) were evaluated. Results indicated that children with ASD, similar to their TD peers, integrated the context to access the correct homonym meanings while reading. However, after reading the sentences, when participants were asked to select the meanings, both groups experienced semantic interference between the two meanings. This semantic interference hindered the children with ASD's sentence representation to a greater degree than their peers. Individual differences in age/development, word recognition, vocabulary breadth (i.e., number of words in the lexicon), and vocabulary depth (i.e., knowledge of the homonym meanings) contributed to sentence comprehension in both children with ASD and their peers. Together, this evidence supports a multi-component view, and that helping children with ASD develop vocabulary depth may have cascading effects on their reading comprehension. Autism Res 2017, 10: 2002-2022. © 2017 International Society for Autism Research, Wiley Periodicals, Inc. Like their peers, children with ASD were able to integrate context, or link words while reading

  17. A method to reduce ambiguities of qualitative reasoning for conceptual design applications

    NARCIS (Netherlands)

    D'Amelio, V.; Chmarra, M.K.; Tomiyama, T.

    2013-01-01

    Qualitative reasoning can generate ambiguous behaviors due to the lack of quantitative information. Despite many different research results focusing on ambiguities reduction, fundamentally it is impossible to totally remove ambiguities with only qualitative methods and to guarantee the consistency

  18. Young children show representational flexibility when interpreting drawings.

    Science.gov (United States)

    Allen, Melissa L; Nurmsoo, Erika; Freeman, Norman

    2016-02-01

    Drawings can be ambiguous and represent more than one entity. In three experiments, we examine whether young children show representational flexibility by allowing one picture to be called by a second name. We also evaluate the hypothesis that children who are representationally flexible see the artist's intention as binding, rather than changeable. In Experiment 1, an artist declared what she intended to draw (e.g. a balloon) but then produced an ambiguous drawing. Children were asked whether the drawings could be interpreted differently (e.g. 'could this be a lollipop?') in the presence of a perceptually similar or dissimilar distractor (e.g., lollipop or snake). Six-year-olds accepted two labels for drawings in both conditions, but four-year-olds only did so in the dissimilar condition. Experiment 2 probed each possible interpretation more deeply by asking property questions (e.g., 'does it float?, does it taste good?'). Preschoolers who understood that the ambiguous drawing could be given two interpretations nevertheless mostly endorsed only properties associated with the prior intent. Experiment 3 provided converging evidence that 4-year-olds were representationally flexible using a paradigm that did not rely upon modal questioning. Taken together, our results indicate that even 4-year-olds understand that pictures may denote more than one referent, they still think of the symbol as consistent with the artist's original intention. Copyright © 2015 Elsevier B.V. All rights reserved.

  19. Extent of the Immirzi ambiguity in quantum general relativity

    International Nuclear Information System (INIS)

    Marugan, Guillermo A Mena

    2002-01-01

    The Ashtekar-Barbero formulation of general relativity admits a one-parameter family of canonical transformations that preserves the expressions of the Gauss and diffeomorphism constraints. The loop quantization of the connection formalism based on each of these canonical sets leads to different predictions. This phenomenon is called the Immirzi ambiguity. It has been recently argued that this ambiguity could be generalized to the extent of a spatially dependent function instead of a parameter. This would ruin the predictability of loop quantum gravity. We prove that such expectations are not realized, so that the Immirzi ambiguity introduces exclusively a freedom in the choice of a real number. (letter to the editor)

  20. Characteristics of a pure-state ambiguity function

    International Nuclear Information System (INIS)

    Praxmeyer, Ludmila; Vitanov, Nikolay; Stenholm, Stig

    2009-01-01

    We present the necessary and sufficient condition for a square integrable function on R 2N to be an ambiguity function corresponding to a square integrable function on R N . This condition has the form of an integral equation. We also list some easier to check necessary conditions that must be fulfilled by a function that is an ambiguity function of a pure state. We show how to construct a wavefunction corresponding to a given ambiguity function and we present examples of how our formal results can be used in practice.

  1. Renormalization ambiguities and conformal anomaly in metric-scalar backgrounds

    International Nuclear Information System (INIS)

    Asorey, M.; Berredo-Peixoto, G. de; Shapiro, I. L.

    2006-01-01

    We analyze the problem of the existing ambiguities in the conformal anomaly in theories with an external scalar field in curved backgrounds. In particular, we consider the anomaly of a self-interacting massive scalar field theory and of a Yukawa model in the massless conformal limit. In all cases the ambiguities are related to finite renormalizations of local nonminimal terms in the effective action. We point out the generic nature of this phenomenon and provide a general method to identify the theories where such an ambiguity can arise

  2. Ambiguity in Tactile Apparent Motion Perception.

    Directory of Open Access Journals (Sweden)

    Emanuela Liaci

    Full Text Available In von Schiller's Stroboscopic Alternative Motion (SAM stimulus two visually presented diagonal dot pairs, located on the corners of an imaginary rectangle, alternate with each other and induce either horizontal, vertical or, rarely, rotational motion percepts. SAM motion perception can be described by a psychometric function of the dot aspect ratio ("AR", i.e. the relation between vertical and horizontal dot distances. Further, with equal horizontal and vertical dot distances (AR = 1 perception is biased towards vertical motion. In a series of five experiments, we presented tactile SAM versions and studied the role of AR and of different reference frames for the perception of tactile apparent motion.We presented tactile SAM stimuli and varied the ARs, while participants reported the perceived motion directions. Pairs of vibration stimulators were attached to the participants' forearms and stimulator distances were varied within and between forearms. We compared straight and rotated forearm conditions with each other in order to disentangle the roles of exogenous and endogenous reference frames.Increasing the tactile SAM's AR biased perception towards vertical motion, but the effect was weak compared to the visual modality. We found no horizontal disambiguation, even for very small tactile ARs. A forearm rotation by 90° kept the vertical bias, even though it was now coupled with small ARs. A 45° rotation condition with crossed forearms, however, evoked a strong horizontal motion bias.Existing approaches to explain the visual SAM bias fail to explain the current tactile results. Particularly puzzling is the strong horizontal bias in the crossed-forearm conditions. In the case of tactile apparent motion, there seem to be no fixed priority rule for perceptual disambiguation. Rather the weighting of available evidence seems to depend on the degree of stimulus ambiguity, the current situation and on the perceptual strategy of the individual

  3. Total urogenital sinus mobilization for ambiguous genitalia.

    Science.gov (United States)

    Jesus, Vinicius Menezes; Buriti, Francisco; Lessa, Rodrigo; Toralles, Maria Betânia; Oliveira, Luciana Barros; Barroso, Ubirajara

    2018-04-01

    Genital ambiguity is a very common phenomenon in disorders of sex development (DSD). According to the Chicago Consensus 2006, feminizing genitoplasty, when indicated, should be performed in the most virilized cases (Prader III to V). Advances in the knowledge of genital anatomy in DSD have enabled the development and improvement of various surgical techniques. Mobilization of the urogenital sinus (MUS), first described by Peña, has become incorporated by most surgeons. However, the proximity of the urethral sphincter prompts concern over urinary incontinence, especially for full mobilization of the urogenital sinus. To retrospectively evaluate the short-term surgical results of feminizing genitoplasty with total mobilization of the urogenital sinus in patients with DSD. Review of medical records of all patients undergoing feminizing genitoplasty with mobilization of the urogenital sinus. We evaluated the rates of complications from surgery and of urinary incontinence, as well as cosmetic results, according to the opinion of the surgeon and the family. A total of 8 patients were included in the study. The mean age at surgery was 51months. Congenital adrenal hyperplasia (CAH) was diagnosed in six patients, and gonadal dysgenesis in the other two. The vagina was separated from the urethra, with suitable distance in all cases. No patient had urinary incontinence after surgery. The mean follow-up of patients was. 20months (3-56months). In all cases, surgeons recorded being satisfied with the aesthetic result of post-surgical genitalia. The family was recorded as satisfied with the aesthetic result of the genitalia after surgery. In every case, there was no need for a second surgical procedure. The total mobilization of the urogenital sinus is a feasible and safe technique. The technique permits good cosmetic results, and urinary incontinence is absent. Therapeutic study. Level III. Copyright © 2017 Elsevier Inc. All rights reserved.

  4. Cortical representations of communication sounds.

    Science.gov (United States)

    Heiser, Marc A; Cheung, Steven W

    2008-10-01

    This review summarizes recent research into cortical processing of vocalizations in animals and humans. There has been a resurgent interest in this topic accompanied by an increased number of studies using animal models with complex vocalizations and new methods in human brain imaging. Recent results from such studies are discussed. Experiments have begun to reveal the bilateral cortical fields involved in communication sound processing and the transformations of neural representations that occur among those fields. Advances have also been made in understanding the neuronal basis of interaction between developmental exposures and behavioral experiences with vocalization perception. Exposure to sounds during the developmental period produces large effects on brain responses, as do a variety of specific trained tasks in adults. Studies have also uncovered a neural link between the motor production of vocalizations and the representation of vocalizations in cortex. Parallel experiments in humans and animals are answering important questions about vocalization processing in the central nervous system. This dual approach promises to reveal microscopic, mesoscopic, and macroscopic principles of large-scale dynamic interactions between brain regions that underlie the complex phenomenon of vocalization perception. Such advances will yield a greater understanding of the causes, consequences, and treatment of disorders related to speech processing.

  5. Top-down influences on ambiguous perception: the role of stable and transient states of the observer

    Science.gov (United States)

    Scocchia, Lisa; Valsecchi, Matteo; Triesch, Jochen

    2014-01-01

    The world as it appears to the viewer is the result of a complex process of inference performed by the brain. The validity of this apparently counter-intuitive assertion becomes evident whenever we face noisy, feeble or ambiguous visual stimulation: in these conditions, the state of the observer may play a decisive role in determining what is currently perceived. On this background, ambiguous perception and its amenability to top-down influences can be employed as an empirical paradigm to explore the principles of perception. Here we offer an overview of both classical and recent contributions on how stable and transient states of the observer can impact ambiguous perception. As to the influence of the stable states of the observer, we show that what is currently perceived can be influenced (1) by cognitive and affective aspects, such as meaning, prior knowledge, motivation, and emotional content and (2) by individual differences, such as gender, handedness, genetic inheritance, clinical conditions, and personality traits and by (3) learning and conditioning. As to the impact of transient states of the observer, we outline the effects of (4) attention and (5) voluntary control, which have attracted much empirical work along the history of ambiguous perception. In the huge literature on the topic we trace a difference between the observer's ability to control dominance (i.e., the maintenance of a specific percept in visual awareness) and reversal rate (i.e., the switching between two alternative percepts). Other transient states of the observer that have more recently drawn researchers' attention regard (6) the effects of imagery and visual working memory. (7) Furthermore, we describe the transient effects of prior history of perceptual dominance. (8) Finally, we address the currently available computational models of ambiguous perception and how they can take into account the crucial share played by the state of the observer in perceiving ambiguous displays. PMID

  6. Ambiguity Of Doppler Centroid In Synthetic-Aperture Radar

    Science.gov (United States)

    Chang, Chi-Yung; Curlander, John C.

    1991-01-01

    Paper discusses performances of two algorithms for resolution of ambiguity in estimated Doppler centroid frequency of echoes in synthetic-aperture radar. One based on range-cross-correlation technique, other based on multiple-pulse-repetition-frequency technique.

  7. The Benefit of Ambiguity in Understanding Goals in Requirements Modelling

    DEFF Research Database (Denmark)

    Paay, Jeni; Pedell, Sonja; Sterling, Leon

    2011-01-01

    This paper examines the benefit of ambiguity in describing goals in requirements modelling for the design of socio-technical systems using concepts from Agent-Oriented Software Engineering (AOSE) and ethnographic and cultural probe methods from Human Computer Interaction (HCI). The authors’ aim...... ambiguity in the process of elicitation and analysis through the use of empirically informed quality goals attached to functional goals. The authors demonstrate the benefit of articulating a quality goal without turning it into a functional goal. Their study shows that quality goals kept at a high level...... of abstraction, ambiguous and open for conversations through the modelling process add richness to goal models, and communicate quality attributes of the interaction being modelled to the design phase, where this ambiguity is regarded as a resource for design....

  8. Pricing risk and ambiguity : The effect of perspective taking

    NARCIS (Netherlands)

    Trautmann, S.T.; Schmidt, U.

    2012-01-01

    In the valuation of uncertain prospects, a difference is often observed between selling and buying perspectives. This paper distinguishes between risk (known probabilities) and ambiguity (unknown probabilities) in decisions under uncertainty and shows that the valuation disparity increases under

  9. PRF Ambiguity Detrmination for Radarsat ScanSAR System

    Science.gov (United States)

    Jin, Michael Y.

    1998-01-01

    PRF ambiguity is a potential problem for a spaceborne SAR operated at high frequencies. For a strip mode SAR, there were several approaches to solve this problem. This paper, however, addresses PRF ambiguity determination algorithms suitable for a burst mode SAR system such as the Radarsat ScanSAR. The candidate algorithms include the wavelength diversity algorithm, range look cross correlation algorithm, and multi-PRF algorithm.

  10. An ambiguity in one-loop quantum gravity

    International Nuclear Information System (INIS)

    Capper, D.M.; Kimber, D.P.

    1980-01-01

    It is argued that the application of the dimensional regularisation technique to one-loop quantum gravity calculations is ambiguous. However, for the calculation of on-mass-shell S-matrix elements, this ambiguity can be resolved by requiring consistency with results obtained from other regularisation schemes. Some discussion is also given of the implications of this work for recent attempts to use higher derivative Lagrangians to solve the renormalisability problem in quantum gravity. (author)

  11. Ambiguities of the natural gauge in Yang-Mills theories

    International Nuclear Information System (INIS)

    Lazarides, G.

    1978-01-01

    We study the ambiguities of the natural gauge condition for the Euclidean SU(2) Yang-Mills theory in four dimensions. Then, we show that, in the stationary-phase approximation, these ambiguities do not affect the contribution of the sector with Pontryagin index q = 1 to the correlation functions of gauge-invariant operators. They affect only the higher-order corrections to this contribution

  12. Quantization ambiguity and non-trivial vacuum structure

    International Nuclear Information System (INIS)

    Rothe, H.J.; Swieca, J.A.

    1978-01-01

    It is pointed out that there is an ambiguity in quantization of any system whose configuration space has a non-trivial topology characterized by a Chern number. In field theories this ambiguity manifests itself through the existence of theta-sectors. The point of view adopted gives a simple interpretation of the difference between the temporal and Coulomb gauge descriptions of instantons. The general ideas are exemplified in the O(3) non-linear sigma-model in two dimensions [pt

  13. Removing Ambiguities of IP Telephony Traffic Using Protocol Scrubbers

    Directory of Open Access Journals (Sweden)

    Bazara I. A. Barry

    2012-10-01

    Full Text Available Network intrusion detection systems (NIDSs face the serious challenge of attacks such as insertion and evasion attacks that are caused by ambiguous network traffic. Such ambiguity comes as a result of the nature of network traffic which includes protocol implementation variations and errors alongside legitimate network traffic. Moreover, attackers can intentionally introduce further ambiguities in the traffic. Consequently, NIDSs need to be aware of these ambiguities when detection is performed and make sure to differentiate between true attacks and protocol implementation variations or errors; otherwise, detection accuracy can be affected negatively. In this paper we present the design and implementation of tools that are called protocol scrubbers whose main functionality is to remove ambiguities from network traffic before it is presented to the NIDS. The proposed protocol scrubbers are designed for session initiation and data transfer protocols in IP telephony systems. They guarantee that the traffic presented to NIDSs is unambiguous by eliminating ambiguous behaviors of protocols using well-designed protocol state machines, and walking through packet headers of protocols to make sure packets will be interpreted in the desired way by the NIDS. The experimental results shown in this paper demonstrate the good quality and applicability of the introduced scrubbers.

  14. Preferences for 'New' Treatments Diminish in the Face of Ambiguity.

    Science.gov (United States)

    Harrison, Mark; Marra, Carlo A; Bansback, Nick

    2017-06-01

    New products usually offer advantages over existing products, but in health care, most new drugs are 'me-too', comparable in effectiveness and side effects to existing drugs, but with a more ambiguous evidence base around adverse effects. Despite this, new treatments drive increased health care spending, suggesting a preference for 'newness' in this setting. We explore (1) whether preferences for treatments labeled 'new' exist and (2) persist once the ambiguity in the evidence base reflecting newness is described. We use a Canadian general population sample (n = 2837) characterized by their innovativeness in adopting new products in normal markets. We found that innovators/early adopters (n = 173) had significant preferences for 'newer' treatments (B = 0.162, p = 0.038) irrespective of comparable benefits and side effects and all respondents had significant preferences for less ambiguity in benefit/side effect estimates. Notably, when 'newness' was combined with ambiguity, no significant preferences for new treatments were observed regardless of respondent innovativeness. We conclude that preferences for new products exist for some people in health care markets but disappear when the implication of ambiguity in the evidence base for new treatments is communicated. Physicians should avoid describing treatments as 'new' or be mindful to qualify the implications of 'new' treatments in terms of evidence ambiguity. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  15. Isoclinic Ambiguity Unwrapping of Circular Ring under Diametric Compression

    Directory of Open Access Journals (Sweden)

    Huang M.-J.

    2010-06-01

    Full Text Available Isoclinic and isochromatic parameters in photoelastic analysis are formulated by arc tangent function of several phase shifting frames but for isochromatic calculation it is, in addition, in terms of isoclinic data also. Thus, any isoclinic phase ambiguity would also result in the phase inconsistencies of isochromatic calculation and cause unwrapping problems and difficulties. Many methods had been proposed to treat these kinds of isochromatic fringes but lots of treatments were needed for the correct retrieval. In this work, the isoclinic ambiguity problem is investigated and solved directly by a novel regional phase unwrapping technique. Once the isoclinic phase ambiguity problems are solved, a correct isoclinic result can be obtained. Then, substituting this result into the isochromatic formation yields an ambiguity free isochromatic phase map, which can be easily restored by any phase unwrapping algorithm. A stress frozen sample - circular ring under diametric compression verifies its effectiveness. Usually happened is that this kind of sample is with ambiguous isoclinic data which would cause phase ambiguities of the isochromatic formulation if not treated well first.

  16. Representation in Memory.

    Science.gov (United States)

    Rumelhart, David E.; Norman, Donald A.

    This paper reviews work on the representation of knowledge from within psychology and artificial intelligence. The work covers the nature of representation, the distinction between the represented world and the representing world, and significant issues concerned with propositional, analogical, and superpositional representations. Specific topics…

  17. Estimating ambiguity preferences and perceptions in multiple prior models: Evidence from the field

    Science.gov (United States)

    Dimmock, Stephen G.; Kouwenberg, Roy; Mitchell, Olivia S.; Peijnenburg, Kim

    2016-01-01

    We develop a tractable method to estimate multiple prior models of decision-making under ambiguity. In a representative sample of the U.S. population, we measure ambiguity attitudes in the gain and loss domains. We find that ambiguity aversion is common for uncertain events of moderate to high likelihood involving gains, but ambiguity seeking prevails for low likelihoods and for losses. We show that choices made under ambiguity in the gain domain are best explained by the α-MaxMin model, with one parameter measuring ambiguity aversion (ambiguity preferences) and a second parameter quantifying the perceived degree of ambiguity (perceptions about ambiguity). The ambiguity aversion parameter α is constant and prior probability sets are asymmetric for low and high likelihood events. The data reject several other models, such as MaxMin and MaxMax, as well as symmetric probability intervals. Ambiguity aversion and the perceived degree of ambiguity are both higher for men and for the college-educated. Ambiguity aversion (but not perceived ambiguity) is also positively related to risk aversion. In the loss domain, we find evidence of reflection, implying that ambiguity aversion for gains tends to reverse into ambiguity seeking for losses. Our model’s estimates for preferences and perceptions about ambiguity can be used to analyze the economic and financial implications of such preferences. PMID:26924890

  18. Estimating ambiguity preferences and perceptions in multiple prior models: Evidence from the field.

    Science.gov (United States)

    Dimmock, Stephen G; Kouwenberg, Roy; Mitchell, Olivia S; Peijnenburg, Kim

    2015-12-01

    We develop a tractable method to estimate multiple prior models of decision-making under ambiguity. In a representative sample of the U.S. population, we measure ambiguity attitudes in the gain and loss domains. We find that ambiguity aversion is common for uncertain events of moderate to high likelihood involving gains, but ambiguity seeking prevails for low likelihoods and for losses. We show that choices made under ambiguity in the gain domain are best explained by the α-MaxMin model, with one parameter measuring ambiguity aversion (ambiguity preferences) and a second parameter quantifying the perceived degree of ambiguity (perceptions about ambiguity). The ambiguity aversion parameter α is constant and prior probability sets are asymmetric for low and high likelihood events. The data reject several other models, such as MaxMin and MaxMax, as well as symmetric probability intervals. Ambiguity aversion and the perceived degree of ambiguity are both higher for men and for the college-educated. Ambiguity aversion (but not perceived ambiguity) is also positively related to risk aversion. In the loss domain, we find evidence of reflection, implying that ambiguity aversion for gains tends to reverse into ambiguity seeking for losses. Our model's estimates for preferences and perceptions about ambiguity can be used to analyze the economic and financial implications of such preferences.

  19. Contingency bias in probability judgement may arise from ambiguity regarding additional causes.

    Science.gov (United States)

    Mitchell, Chris J; Griffiths, Oren; More, Pranjal; Lovibond, Peter F

    2013-09-01

    In laboratory contingency learning tasks, people usually give accurate estimates of the degree of contingency between a cue and an outcome. However, if they are asked to estimate the probability of the outcome in the presence of the cue, they tend to be biased by the probability of the outcome in the absence of the cue. This bias is often attributed to an automatic contingency detection mechanism, which is said to act via an excitatory associative link to activate the outcome representation at the time of testing. We conducted 3 experiments to test alternative accounts of contingency bias. Participants were exposed to the same outcome probability in the presence of the cue, but different outcome probabilities in the absence of the cue. Phrasing the test question in terms of frequency rather than probability and clarifying the test instructions reduced but did not eliminate contingency bias. However, removal of ambiguity regarding the presence of additional causes during the test phase did eliminate contingency bias. We conclude that contingency bias may be due to ambiguity in the test question, and therefore it does not require postulation of a separate associative link-based mechanism.

  20. On the usage of ultrasound computational models for decision making under ambiguity

    Science.gov (United States)

    Dib, Gerges; Sexton, Samuel; Prowant, Matthew; Crawford, Susan; Diaz, Aaron

    2018-04-01

    Computer modeling and simulation is becoming pervasive within the non-destructive evaluation (NDE) industry as a convenient tool for designing and assessing inspection techniques. This raises a pressing need for developing quantitative techniques for demonstrating the validity and applicability of the computational models. Computational models provide deterministic results based on deterministic and well-defined input, or stochastic results based on inputs defined by probability distributions. However, computational models cannot account for the effects of personnel, procedures, and equipment, resulting in ambiguity about the efficacy of inspections based on guidance from computational models only. In addition, ambiguity arises when model inputs, such as the representation of realistic cracks, cannot be defined deterministically, probabilistically, or by intervals. In this work, Pacific Northwest National Laboratory demonstrates the ability of computational models to represent field measurements under known variabilities, and quantify the differences using maximum amplitude and power spectrum density metrics. Sensitivity studies are also conducted to quantify the effects of different input parameters on the simulation results.

  1. Neural Representations of Physics Concepts.

    Science.gov (United States)

    Mason, Robert A; Just, Marcel Adam

    2016-06-01

    We used functional MRI (fMRI) to assess neural representations of physics concepts (momentum, energy, etc.) in juniors, seniors, and graduate students majoring in physics or engineering. Our goal was to identify the underlying neural dimensions of these representations. Using factor analysis to reduce the number of dimensions of activation, we obtained four physics-related factors that were mapped to sets of voxels. The four factors were interpretable as causal motion visualization, periodicity, algebraic form, and energy flow. The individual concepts were identifiable from their fMRI signatures with a mean rank accuracy of .75 using a machine-learning (multivoxel) classifier. Furthermore, there was commonality in participants' neural representation of physics; a classifier trained on data from all but one participant identified the concepts in the left-out participant (mean accuracy = .71 across all nine participant samples). The findings indicate that abstract scientific concepts acquired in an educational setting evoke activation patterns that are identifiable and common, indicating that science education builds abstract knowledge using inherent, repurposed brain systems. © The Author(s) 2016.

  2. Distinguishing Representations as Origin and Representations as Input: Roles for Individual Cells

    Directory of Open Access Journals (Sweden)

    Jonathan C.W. Edwards

    2016-09-01

    input interaction between signals and consumer. The acceptance of this necessity provides a basis for resolving the problem that representations appear both as distributed (representation-as-origin and local (representation-as-input. The key implications are that representations in brain are massively multiple both in series and in parallel, and that individual cells play specific semantic roles. These roles are discussed in relation to traditional concepts of ‘gnostic’ cell types.

  3. Rainbow-shift mechanism behind discrete optical-potential ambiguities

    International Nuclear Information System (INIS)

    Brandan, M.E.; McVoy, K.W.

    1991-01-01

    Some years ago, Drisko et al. suggested that the discrete ambiguity often encountered for elastic scattering optical potentials could be understood as being due to the interior or small-l S-matrix elements for two ''equivalent'' potentials differing in phase by 2π, l-by-l. We point out that the absence of this phase change for peripheral partial waves is equally essential, and suggest that a deeper understanding of the ambiguity may be achieved by viewing it as a consequence of a farside interference between interior and peripheral partial waves. It is this interference which produces the broad ''Airy maxima'' of a nuclear rainbow, and we show that a Drisko-type phase-shift increment δ l →(δ l +π) for low-l phases relative to the high-l ones is exactly what is needed to shift a farside rainbow pattern by one Airy maximum, thus providing an equivalent ''rainbow-shift'' interpretation of the discrete ambiguity. The physical importance of both interpretations lies in the fact that the existence of discrete ambiguities (as well as of nuclear rainbows) is explicit evidence for low-l transparency in nucleus-nucleus collisions. The essential role played by low partial waves explains why peripheral reactions have generally not proven helpful in resolving this ambiguity

  4. Increasing Statistical Literacy by Exploiting Lexical Ambiguity of Technical Terms

    Directory of Open Access Journals (Sweden)

    Jennifer Kaplan

    2018-01-01

    Full Text Available Instructional inattention to language poses a barrier for students in entry-level science courses, in part because students may perceive a subject as difficult solely based on the lack of understanding of the vocabulary. In addition, the technical use of terms that have different everyday meanings may cause students to misinterpret statements made by instructors, leading to an incomplete or incorrect understanding of the domain. Terms that have different technical and everyday meanings are said to have lexical ambiguity and statistics, as a discipline, has many lexically ambiguous terms. This paper presents a cyclic process for designing activities to address lexical ambiguity in statistics. In addition, it describes three short activities aimed to have high impact on student learning associated with two different lexically ambiguous words or word pairs in statistics. Preliminary student-level data are used to assess the efficacy of the activities, and future directions for development of activities and research about lexical ambiguity in statistics in particular and STEM in general are discussed.

  5. Understanding representations in design

    DEFF Research Database (Denmark)

    Bødker, Susanne

    1998-01-01

    Representing computer applications and their use is an important aspect of design. In various ways, designers need to externalize design proposals and present them to other designers, users, or managers. This article deals with understanding design representations and the work they do in design....... The article is based on a series of theoretical concepts coming out of studies of scientific and other work practices and on practical experiences from design of computer applications. The article presents alternatives to the ideas that design representations are mappings of present or future work situations...... and computer applications. It suggests that representations are primarily containers of ideas and that representation is situated at the same time as representations are crossing boundaries between various design and use activities. As such, representations should be carriers of their own contexts regarding...

  6. Scheme-scale ambiguity in analysis of QCD observable

    International Nuclear Information System (INIS)

    Mirjalili, A.; Kniehl, B.A.

    2010-01-01

    The scheme-scale ambiguity that has plagued perturbative analysis in QCD remains on obstacle to making precise tests of the theory. Many attempts have been done to resolve the scale ambiguity. In this regard the BLM, EC, PMS and CORGI approaches are more distinct. We try to employ these methods to fix the scale ambiguity at NLO, NNLO and even in more higher order approximations. By optimizing the renormalization scale, there will be a possibility to predicate higher order terms. We present general results for predicted terms at any order, using different optimization methods. Some observable as specific examples will be used to indicate the validity of scale fixing to predicate the higher order terms. (authors)

  7. Phase ambiguity resolution for offset QPSK modulation systems

    Science.gov (United States)

    Nguyen, Tien M. (Inventor)

    1991-01-01

    A demodulator for Offset Quaternary Phase Shift Keyed (OQPSK) signals modulated with two words resolves eight possible combinations of phase ambiguity which may produce data error by first processing received I(sub R) and Q(sub R) data in an integrated carrier loop/symbol synchronizer using a digital Costas loop with matched filters for correcting four of eight possible phase lock errors, and then the remaining four using a phase ambiguity resolver which detects the words to not only reverse the received I(sub R) and Q(sub R) data channels, but to also invert (complement) the I(sub R) and/or Q(sub R) data, or to at least complement the I(sub R) and Q(sub R) data for systems using nontransparent codes that do not have rotation direction ambiguity.

  8. Authoritarianism, cognitive rigidity, and the processing of ambiguous visual information.

    Science.gov (United States)

    Duncan, Lauren E; Peterson, Bill E

    2014-01-01

    Intolerance of ambiguity and cognitive rigidity are unifying aspects of authoritarianism as defined by Adorno, Frenkel-Brunswik, Levinson, and Sanford (1982/1950), who hypothesized that authoritarians view the world in absolute terms (e.g., good or evil). Past studies have documented the relationship between authoritarianism and intolerance of ambiguity and rigidity. Frenkel-Brunswik (1949) hypothesized that this desire for absolutism was rooted in perceptual processes. We present a study with three samples that directly tests the relationship between right wing authoritarianism (RWA) and the processing of ideologically neutral but ambiguous visual stimuli. As hypothesized, in all three samples we found that RWA was related to the slower processing of visual information that required participants to recategorize objects. In a fourth sample, RWA was unrelated to speed of processing visual information that did not require recategorization. Overall, results suggest a relationship between RWA and rigidity in categorization.

  9. A study of ultraviolet renormalon ambiguities in the determination of αS from τdecay

    International Nuclear Information System (INIS)

    Altarelli, G.; Nason, P.; Ridolfi, G.

    1995-01-01

    The divergent large-order behaviour of the perturbative series relevant for the determination of α S from τ decay is controlled by the leading ultraviolet (UV) renormalon. Even in the absence of the first infrared (IR) renormalon, an ambiguity of order Λ 2 /m 2 τ is introduced. We make a quantitative study of the practical implications of this ambiguity. We discuss the magnitude of UV renormalon corrections obtained in the large-N f limit, which, although unrealistic, is nevertheless interesting to some extent. We then study a number of improved approximants for the perturbative series, based on a change of variable in the Borel representation, such as to displace the leading UV renormalon singularity at a larger distance from the origin than the first IR renormalon. The spread of the resulting values of α S (m 2 τ ) obtained by different approximants, at different renormalization scales, is exhibited as a measure of the underlying ambiguities. Finally, on the basis of mathematical models, we discuss the prospects of an actual improvement, given the signs and magnitudes of the computed coefficients, the size of α S (m 2 τ ) and what is known of the asymptotic properties of the series. Our conclusion is that a realistic estimate of the theoretical error cannot go below δα S (m 2 τ )∼ ± 0.060, or δα S (m 2 Z )∼ ± 0.006. (orig.)

  10. Li Shangyin and the Art of Poetic Ambiguity

    Directory of Open Access Journals (Sweden)

    Maja Lavrač

    2016-12-01

    Full Text Available Li Shangyin (813–858, one of the most respected, mysterious, ambiguous and provocative of Chinese poets, lived during the late Tang period, when the glorious Tang dynasty was beginning to decline. It was a time of social riots, political division and painful general insecurity. Li Shangyin is famous as a highly original and committed poet who developed a unique style full of vague allusions and unusual images derived from the literary past (the traditional canon, myths and legends as well as from nature and personal experience. The second important feature of his poetry is a mysteriousness which finally leads to ambiguity. Ambiguity plays an essential role in most of his renowned poems, and he uses it to superbly connect present and past, reality and fantasy, and history and mythology. Thus, ambiguity and obscurity, respectively, often engender different interpretations among Chinese critics. These interpretations reflect the poems’ imaginative qualities, hypotheses and contradictions. Since each interpretive direction emphasizes but a single aspect of the poet’s character, it is more fitting to understand his ambiguous poems in symbolic terms. Such understanding entails that the meaning of the poem is not limited to one interpretation; rather, the poem’s poetic landscape opens itself up to various interpretations. Li Shangyin is actually most popular for his melancholic love poetry that reveals his ambiguous attitude to love. In this poetry, love is shrouded in a secret message. On the one hand, we can sense his moral disapproval of a secret but hopeless love; on the other, we can sense his passion. This leads to a paradox: the pleasing temptations of an illicit romance also exact a high price. In these love poems Li investigates various aspects of the worlds of passion which stoke in him feelings of rapture, satisfaction, joy and hope as well as feelings of doubt, frustration, despair and even thoughts of death.

  11. A Possible Neural Representation of Mathematical Group Structures.

    Science.gov (United States)

    Pomi, Andrés

    2016-09-01

    Every cognitive activity has a neural representation in the brain. When humans deal with abstract mathematical structures, for instance finite groups, certain patterns of activity are occurring in the brain that constitute their neural representation. A formal neurocognitive theory must account for all the activities developed by our brain and provide a possible neural representation for them. Associative memories are neural network models that have a good chance of achieving a universal representation of cognitive phenomena. In this work, we present a possible neural representation of mathematical group structures based on associative memory models that store finite groups through their Cayley graphs. A context-dependent associative memory stores the transitions between elements of the group when multiplied by each generator of a given presentation of the group. Under a convenient election of the vector basis mapping the elements of the group in the neural activity, the input of a vector corresponding to a generator of the group collapses the context-dependent rectangular matrix into a virtual square permutation matrix that is the matrix representation of the generator. This neural representation corresponds to the regular representation of the group, in which to each element is assigned a permutation matrix. This action of the generator on the memory matrix can also be seen as the dissection of the corresponding monochromatic subgraph of the Cayley graph of the group, and the adjacency matrix of this subgraph is the permutation matrix corresponding to the generator.

  12. That's not quite me: limb ownership encoding in the brain.

    Science.gov (United States)

    Limanowski, Jakub; Blankenburg, Felix

    2016-07-01

    With congruent stimulation of one's limb together with a fake counterpart, an illusory self-attribution of the fake limb can be induced. Such illusions have brought profound insights into the cognitive and neuronal mechanisms underlying temporary changes in body representation, but to put them in perspective, they need to be compared with ownership as experienced for one's real body. We used functional magnetic resonance imaging (fMRI) to compare the neuronal correlates of touch under different degrees of body ownership. Participants' left and right arms were stimulated either alone or together with a fake counterpart while this stimulation was synchronous, ambiguous or asynchronous. Synchronous stimulation induced illusory fake arm ownership, but the brain still differentiated between touch to one's real arm and to an illusory 'owned' arm: the degree of arm ownership was encoded positively by activity in the ventromedial prefrontal cortex and lateral occipitotemporal cortex and negatively in the temporoparietal cortex. Conversely, the ventral premotor cortex responded more strongly to synchronous stimulation compared with asynchronous stimulation and with real arm only stimulation. These results offer new insights into the differential representation of the real body vs a body that is temporarily self-attributed following the resolution of multisensory conflict. © The Author (2015). Published by Oxford University Press. For Permissions, please email: journals.permissions@oup.com.

  13. Absence of the Gribov ambiguity in a special algebraic gauge

    Directory of Open Access Journals (Sweden)

    Raval Haresh

    2016-01-01

    Full Text Available The Gribov ambiguity exists in various gauges except algebraic gauges. However in general, algebraic gauges are not Lorentz invariant, which is their fundamental flaw. Here we discuss a quadratic gauge fixing, which is Lorentz invariant. We show that nontrivial copies can not occur in this gauge. We then provide an example of spherically symmetric gauge field configuration and prove that with a proper boundary condition on the configuration, this gauge removes the ambiguity on a compact manifold S3${{\\mathbb S}^3}$.

  14. Portfolio Management with Stochastic Interest Rates and Inflation Ambiguity

    DEFF Research Database (Denmark)

    Munk, Claus; Rubtsov, Alexey Vladimirovich

    We solve a stock-bond-cash portfolio choice problem for a risk- and ambiguity-averse investor in a setting where the inflation rate and interest rates are stochastic. The expected inflation rate is unobservable, but the investor may learn about it from realized inflation and observed stock and bond......-Jacobi-Bellman equation in closed form and derive and illustrate a number of interesting properties of the solution. For example, ambiguity aversion affects the optimal portfolio through the correlation of price level with the stock index, a bond, and the expected inflation rate. Furthermore, unlike other settings...

  15. Impact of Decorrelation on Search Efficiency of Ambiguity Resolution

    Directory of Open Access Journals (Sweden)

    LU Liguo

    2015-05-01

    Full Text Available The decorrelation performance of LAMBDA algorithm, LLL algorithm and Seysen algorithm are analyzed with evaluation indexes, i.e., condition number, orthogonal defect and S(A. Moreover, relationships between decorrelation performance of the above algorithms and ambiguity search efficiency are evaluated using theoretical and practical validation, respectively. The results validate that there is no inevitable relation between decorrelation performance of variance-covariance matrix of original ambiguity and search efficiency, whereas, traditional views consider that search efficiency can be enhanced just by improving decorrelation performance. Further analysis shows that the essence to improving search efficiency major depends on the permutation of basis vectors according to a certain direction.

  16. Process ambiguities in Sino-Danish Business Negotiations

    DEFF Research Database (Denmark)

    Kumar, Rajesh; Worm, Verner

    2004-01-01

    . These ambiguities stem from differences in negotiation scripts across Danish and Chinese cultures. The essential argument being advanced here is that it is the effective and/or the ineffective management of process ambiguities that shapes the evolution of the negotiating dynamic between the Danish and the Chinese...... businesspeople. An inductive model of sino-Danish negotiations is developed that is based on 24 interviews conducted with Danish expatriate managers in China and 4 interviews with Chinese working in Danish companies. Implications for research and practice are discussed...

  17. Community representation in hospital decision making: a literature review.

    Science.gov (United States)

    Murray, Zoë

    2015-06-01

    Advancing quality in health services requires structures and processes that are informed by consumer input. Although this agenda is well recognised, few researchers have focussed on the establishment and maintenance of customer input throughout the structures and processes used to produce high-quality, safe care. We present an analysis of literature outlining the barriers and enablers involved in community representation in hospital governance. The review aimed to explore how community representation in hospital governance is achieved. Studies spanning 1997-2012 were analysed using Donabedian' s model of quality systems as a guide for categories of interest: structure, in relation to administration of quality; process, which is particularly concerned with cooperation and culture; and outcome, considered, in this case, to be the achievement of effective community representation on quality of care. There are limited published studies on community representation in hospital governance in Australia. What can be gleaned from the literature is: 1) quality subcommittees set up to assist Hospital Boards are a key structure for involving community representation in decision making around quality of care, and 2) there are a number of challenges to effectively developing the process of community representation in hospital governance: ambiguity and the potential for escalated indecision; inadequate value and consideration given to it by decision makers resulting in a lack of time and resources needed to support the community engagement strategy (time, facilitation, budgets); poor support and attitude amongst staff; and consumer issues, such as feeling isolated and intimidated by expert opinion. The analysis indicates that: quality subcommittees set up to assist boards are a key structure for involving community representation in decision making around quality of care. There are clearly a number of challenges to effectively developing the process of community representation in

  18. Tracking down abstract linguistic meaning: neural correlates of spatial frame of reference ambiguities in language.

    Directory of Open Access Journals (Sweden)

    Gabriele Janzen

    Full Text Available This functional magnetic resonance imaging (fMRI study investigates a crucial parameter in spatial description, namely variants in the frame of reference chosen. Two frames of reference are available in European languages for the description of small-scale assemblages, namely the intrinsic (or object-oriented frame and the relative (or egocentric frame. We showed participants a sentence such as "the ball is in front of the man", ambiguous between the two frames, and then a picture of a scene with a ball and a man--participants had to respond by indicating whether the picture did or did not match the sentence. There were two blocks, in which we induced each frame of reference by feedback. Thus for the crucial test items, participants saw exactly the same sentence and the same picture but now from one perspective, now the other. Using this method, we were able to precisely pinpoint the pattern of neural activation associated with each linguistic interpretation of the ambiguity, while holding the perceptual stimuli constant. Increased brain activity in bilateral parahippocampal gyrus was associated with the intrinsic frame of reference whereas increased activity in the right superior frontal gyrus and in the parietal lobe was observed for the relative frame of reference. The study is among the few to show a distinctive pattern of neural activation for an abstract yet specific semantic parameter in language. It shows with special clarity the nature of the neural substrate supporting each frame of spatial reference.

  19. Embedded data representations

    DEFF Research Database (Denmark)

    Willett, Wesley; Jansen, Yvonne; Dragicevic, Pierre

    2017-01-01

    We introduce embedded data representations, the use of visual and physical representations of data that are deeply integrated with the physical spaces, objects, and entities to which the data refers. Technologies like lightweight wireless displays, mixed reality hardware, and autonomous vehicles...

  20. Group and representation theory

    CERN Document Server

    Vergados, J D

    2017-01-01

    This volume goes beyond the understanding of symmetries and exploits them in the study of the behavior of both classical and quantum physical systems. Thus it is important to study the symmetries described by continuous (Lie) groups of transformations. We then discuss how we get operators that form a Lie algebra. Of particular interest to physics is the representation of the elements of the algebra and the group in terms of matrices and, in particular, the irreducible representations. These representations can be identified with physical observables. This leads to the study of the classical Lie algebras, associated with unitary, unimodular, orthogonal and symplectic transformations. We also discuss some special algebras in some detail. The discussion proceeds along the lines of the Cartan-Weyl theory via the root vectors and root diagrams and, in particular, the Dynkin representation of the roots. Thus the representations are expressed in terms of weights, which are generated by the application of the elemen...

  1. Introduction to representation theory

    CERN Document Server

    Etingof, Pavel; Hensel, Sebastian; Liu, Tiankai; Schwendner, Alex

    2011-01-01

    Very roughly speaking, representation theory studies symmetry in linear spaces. It is a beautiful mathematical subject which has many applications, ranging from number theory and combinatorics to geometry, probability theory, quantum mechanics, and quantum field theory. The goal of this book is to give a "holistic" introduction to representation theory, presenting it as a unified subject which studies representations of associative algebras and treating the representation theories of groups, Lie algebras, and quivers as special cases. Using this approach, the book covers a number of standard topics in the representation theories of these structures. Theoretical material in the book is supplemented by many problems and exercises which touch upon a lot of additional topics; the more difficult exercises are provided with hints. The book is designed as a textbook for advanced undergraduate and beginning graduate students. It should be accessible to students with a strong background in linear algebra and a basic k...

  2. Syntactic computations in the language network: Characterising dynamic network properties using representational similarity analysis

    Directory of Open Access Journals (Sweden)

    Lorraine Komisarjevsky Tyler

    2013-05-01

    Full Text Available The core human capacity of syntactic analysis involves a left hemisphere network involving left inferior frontal gyrus (LIFG and posterior middle temporal gyrus (LMTG and the anatomical connections between them. Here we use MEG to determine the spatio-temporal properties of syntactic computations in this network. Listeners heard spoken sentences containing a local syntactic ambiguity (e.g. …landing planes…, at the offset of which they heard a disambiguating verb and decided whether it was an acceptable/unacceptable continuation of the sentence. We charted the time-course of processing and resolving syntactic ambiguity by measuring MEG responses from the onset of each word in the ambiguous phrase and the disambiguating word. We used representational similarity analysis (RSA to characterize syntactic information represented in the LIFG and LpMTG over time and to investigate their relationship to each other. Testing a variety of lexico-syntactic and ambiguity models against the MEG data, our results suggest early lexico-syntactic responses in the LpMTG and later effects of ambiguity in the LIFG, pointing to a clear differentiation in the functional roles of these two regions. Our results suggest the LpMTG represents and transmits lexical information to the LIFG, which responds to and resolves the ambiguity.

  3. A Mindfulness Experiential Small Group to Help Students Tolerate Ambiguity

    Science.gov (United States)

    Bohecker, Lynn; Vereen, Linwood G.; Wells, Pamela C.; Wathen, Cristen C.

    2016-01-01

    This study explored the lived experiences of 20 counselors-in-training (CITs) in a mindfulness experiential small group. Using grounded theory, the authors described a 5-dimensional model for navigating ambiguity. Findings suggest mindfulness training provides CITs self-reflection skills and a greater ability to manage cognitive complexity.

  4. On the robustness and possible accounts of ambiguity aversion

    NARCIS (Netherlands)

    Keren, G.; Gerritsen, L.E.M.

    1999-01-01

    Ambiguity aversion is one of the most robust phenomena documented in the decision making literature, though there are still disagreements concerning what constitutes an adequate account for its occurrence. We describe six experiments that shed additional light on the enigmatic phenomenon of

  5. Resolving ambiguities in reconstructed grain maps using discrete tomography

    DEFF Research Database (Denmark)

    Alpers, A.; Knudsen, E.; Poulsen, H.F.

    2005-01-01

    reconstruct the image from diffraction data, but they are often unable to assign unambiguous values to all pixels. We present an approach that resolves these ambiguous pixels by using a Monte Carlo technique that exploits the discrete nature of the problem and utilizes proven methods of discrete tomography...

  6. Dealing with behavioral ambiguity in textual process descriptions

    NARCIS (Netherlands)

    van der Aa, Han; Leopold, Henrik; Reijers, Hajo A.

    2016-01-01

    Textual process descriptions are widely used in organizations since they can be created and understood by virtually everyone. The inherent ambiguity of natural language, however, impedes the automated analysis of textual process descriptions. While human readers can use their context knowledge to

  7. Sealed bid auctions with ambiguity: theory and experiments

    Czech Academy of Sciences Publication Activity Database

    Chen, Y.; Katuščák, Peter; Ozdenoren, E.

    2007-01-01

    Roč. 136, č. 1 (2007), s. 513-535 ISSN 0022-0531 R&D Projects: GA MŠk LC542 Institutional research plan: CEZ:MSM0021620846 Keywords : sealed bid auctions * ambiguity * experiment Subject RIV: AH - Economics Impact factor: 1.353, year: 2007

  8. Sealed bid auctions with ambiguity: an experimental study

    Czech Academy of Sciences Publication Activity Database

    Chen, Y.; Katuščák, Peter; Ozdenoren, E.

    -, č. 269 (2005), s. 1-75 ISSN 1211-3298 Institutional research plan: CEZ:AV0Z70850503 Keywords : sealed bid auctions * ambiguity * experiment Subject RIV: AH - Economics http://www.cerge-ei.cz/pdf/wp/Wp269.pdf

  9. The Development of Preschoolers' Appreciation of Communicative Ambiguity

    Science.gov (United States)

    Nilsen, Elizabeth S.; Graham, Susan A.

    2012-01-01

    Using a longitudinal design, preschoolers' appreciation of a listener's knowledge of the location of a hidden sticker after the listener was provided with an ambiguous or unambiguous description was assessed. Preschoolers (N = 34) were tested at 3 time points, each 6 months apart (4, 4 1/2, and 5 years). Eye gaze measures demonstrated that…

  10. Psychometric Analysis of Role Conflict and Ambiguity Scales in Academia

    Science.gov (United States)

    Khan, Anwar; Yusoff, Rosman Bin Md.; Khan, Muhammad Muddassar; Yasir, Muhammad; Khan, Faisal

    2014-01-01

    A comprehensive Psychometric Analysis of Rizzo et al.'s (1970) Role Conflict & Ambiguity (RCA) scales were performed after its distribution among 600 academic staff working in six universities of Pakistan. The reliability analysis includes calculation of Cronbach Alpha Coefficients and Inter-Items statistics, whereas validity was determined by…

  11. Static vs Dynamic Auctions with Ambiguity Averse Bidders

    NARCIS (Netherlands)

    Carvalho, M.

    2012-01-01

    Abstract: This paper presents the outcome of a dynamic price-descending auction when the distribution of the private values is uncertain and bidders exhibit ambiguity aversion. In contrast to sealed-bid auctions, in open auctions the bidders get information about the other bidders' private values

  12. How to Capture and Present Complexity, Ambivalence and Ambiguity

    DEFF Research Database (Denmark)

    Ooi, Can-Seng

    Bakhtin was a literary theorist and was the widely acknowledged father of dialogism. This working paper shows how Bakhtin and dialogism can be used to capture complexity, ambivalence and ambiguity in the social world. In following the spirit of dialogism, I will refer to my own research experiences...

  13. Clock ambiguity and the emergence of physical laws

    International Nuclear Information System (INIS)

    Albrecht, Andreas; Iglesias, Alberto

    2008-01-01

    The process of identifying a time variable in time-reparameterization invariant theories results in great ambiguities about the actual laws of physics described by a given theory. A theory set up to describe one set of physical laws can equally well be interpreted as describing any other laws of physics by making a different choice of time variable or clock. In this article we demonstrate how this 'clock ambiguity' arises and then discuss how one might still hope to extract specific predictions about the laws of physics even when the clock ambiguity is present. We argue that a requirement of quasiseparability should play a critical role in such an analysis. As a step in this direction, we compare the Hamiltonian of a local quantum field theory with a completely random Hamiltonian. We find that any random Hamiltonian (constructed in a sufficiently large space) can yield a 'good enough' approximation to a local field theory. Based on this result we argue that theories that suffer from the clock ambiguity may in the end provide a viable fundamental framework for physics in which locality can be seen as a strongly favored (or predicted) emergent behavior. We also speculate on how other key aspects of known physics such as gauge symmetries and Poincare invariance might be predicted to emerge in this framework.

  14. Sublexical Ambiguity Effect in Reading Chinese Disyllabic Compounds

    Science.gov (United States)

    Huang, Hsu-Wen; Lee, Chia-Ying; Tsai, Jie-Li; Tzeng, Ovid J.-L.

    2011-01-01

    For Chinese compounds, neighbors can share either both orthographic forms and meanings, or orthographic forms only. In this study, central presentation and visual half-field (VF) presentation methods were used in conjunction with ERP measures to investigate how readers solve the sublexical semantic ambiguity of the first constituent character in…

  15. Why Ambiguity Detection Is a Predictor of Early Reading Skill

    Science.gov (United States)

    Wankoff, Lorain Szabo; Cairns, Helen Smith

    2009-01-01

    This study was designed to determine the contributions of metalinguistic skill and psycholinguistic processing ability to children's ability to detect the ambiguity of sentences and the relationship among all three factors to early reading ability. A total of 20 first graders and 20 second graders were given tasks testing the following abilities:…

  16. Chasing Ambiguity: Critical Reflections on Working with Dance Graduates

    Science.gov (United States)

    Roe, Sarah

    2017-01-01

    This paper questions whether are we able to foster uncertainty and ambiguity within higher education arts programmes, specifically alongside current institutional demands and embedded pedagogies. If not, then what effect does this have on current dance graduates? I attend to these questions through critical reflections upon my work as a pedagogue,…

  17. Textbook Presentations of Weight: Conceptual Difficulties and Language Ambiguities

    Science.gov (United States)

    Taibu, Rex; Rudge, David; Schuster, David

    2015-01-01

    The term "weight" has multiple related meanings in both scientific and everyday usage. Even among experts and in textbooks, weight is ambiguously defined as either the gravitational force on an object or operationally as the magnitude of the force an object exerts on a measuring scale. This poses both conceptual and language difficulties…

  18. Diffeomorphisms, Anomalies and the Fefferman-Graham Ambiguity

    International Nuclear Information System (INIS)

    Schwimmer, A.; Theisen, S.

    2000-01-01

    Using the Weyl transfomations induced by diffeomorphisms we set up a cohomological problem for the Fefferman-Graham coefficients. The cohomologically nontrivial solutions remove the ambiguity and give the nonlocal terms in the effective action responsible for the trace anomalies. (author)

  19. Ambiguity of the equivalence principle and Hawking's temperature

    NARCIS (Netherlands)

    Hooft, G. 't

    1984-01-01

    There are two inequivalent ways in which the laws of physics in a gravitational field can be related to the laws in an inertial frame, when quantum mechanical effects are taken into account. This leads to an ambiguity in the derivation of Hawking's radiation temperature for a black hole: it could be

  20. Children's Use of Gesture to Resolve Lexical Ambiguity

    Science.gov (United States)

    Kidd, Evan; Holler, Judith

    2009-01-01

    We report on a study investigating 3-5-year-old children's use of gesture to resolve lexical ambiguity. Children were told three short stories that contained two homonym senses; for example, "bat" (flying mammal) and "bat" (sports equipment). They were then asked to re-tell these stories to a second experimenter. The data were coded for the means…

  1. Doctoral Dissertation Defences: Performing Ambiguity between Ceremony and Assessment

    NARCIS (Netherlands)

    van der Heide, Arjen; Rufas, Alix; Supper, Alexandra

    2016-01-01

    Dissertation defenses are ambiguous affairs, which mark both the end of a long process of doctoral education and the inauguration of a doctoral candidate into a body of experts. At Maastricht University (and other Dutch universities), the decision to award a doctoral degree is made on the basis of

  2. Is Multilingualism Linked to a Higher Tolerance of Ambiguity?

    Science.gov (United States)

    DeWaele, Jean-Marc; Wei, Li

    2013-01-01

    The present study investigates the link between multilingualism and the personality trait Tolerance of Ambiguity (TA) among 2158 mono-, bi- and multilinguals. Monolinguals and bilinguals scored significantly lower on TA compared to multilinguals. A high level of global proficiency of various languages was linked to higher TA scores. A stay abroad…

  3. On the Measurement and Properties of Ambiguity in Probabilistic Expectations

    Science.gov (United States)

    Pickett, Justin T.; Loughran, Thomas A.; Bushway, Shawn

    2015-01-01

    Survey respondents' probabilistic expectations are now widely used in many fields to study risk perceptions, decision-making processes, and behavior. Researchers have developed several methods to account for the fact that the probability of an event may be more ambiguous for some respondents than others, but few prior studies have empirically…

  4. The ambiguity of US foreign policy towards Africa

    DEFF Research Database (Denmark)

    Olsen, Gorm Rye

    2017-01-01

    appear incoherent and ambiguous if judged narrowly on the expectation that it only aims to take care of US national security concerns and economic self-interests. The paper concludes that Africa was important to the United States during the presidencies of George W. Bush and Barack Obama because...

  5. The ambiguity of simplicity in quantum and classical simulation

    International Nuclear Information System (INIS)

    Aghamohammadi, Cina; Mahoney, John R.; Crutchfield, James P.

    2017-01-01

    Highlights: • Simplicity depends on whether a system is represented classically or quantally. • We demonstrate that simplicity is unavoidably ambiguous. • Relative simplicity changes order moving between classical and quantum descriptions. • Ambiguity of simplicity bears directly on model selection. - Abstract: A system's perceived simplicity depends on whether it is represented classically or quantally. This is not so surprising, as classical and quantum physics are descriptive frameworks built on different assumptions that capture, emphasize, and express different properties and mechanisms. What is surprising is that, as we demonstrate, simplicity is ambiguous: the relative simplicity between two systems can change sign when moving between classical and quantum descriptions. Here, we associate simplicity with small model-memory. We see that the notions of absolute physical simplicity at best form a partial, not a total, order. This suggests that appeals to principles of physical simplicity, via Ockham's Razor or to the “elegance” of competing theories, may be fundamentally subjective. Recent rapid progress in quantum computation and quantum simulation suggest that the ambiguity of simplicity will strongly impact statistical inference and, in particular, model selection.

  6. "What Happened?" Teaching Attribution Theory through Ambiguous Prompts

    Science.gov (United States)

    McArthur, John

    2011-01-01

    The concept of attribution, "the act of explaining why something happens or why a person acts a particular way," is typically an abstract concept. This 35-50-minute activity invites students to make a series of attributions by asking them "What happened?" in ambiguous scenes presented in class. Then, students retrospectively identify what…

  7. GLONASS CDMA L3 ambiguity resolution and positioning

    NARCIS (Netherlands)

    Zaminpardaz, Safoora; Teunissen, P.J.G.; Nadarajah, Nandakumaran

    2016-01-01

    A first assessment of GLONASS CDMA L3 ambiguity resolution and positioning performance is provided. Our analyses are based on GLONASS L3 data from the satellite pair SVNs 755-801, received by two JAVAD receivers at Curtin University, Perth, Australia. In our analyses, four different versions of

  8. The ambiguity of simplicity in quantum and classical simulation

    Energy Technology Data Exchange (ETDEWEB)

    Aghamohammadi, Cina, E-mail: caghamohammadi@ucdavis.edu; Mahoney, John R., E-mail: jrmahoney@ucdavis.edu; Crutchfield, James P., E-mail: chaos@ucdavis.edu

    2017-04-11

    Highlights: • Simplicity depends on whether a system is represented classically or quantally. • We demonstrate that simplicity is unavoidably ambiguous. • Relative simplicity changes order moving between classical and quantum descriptions. • Ambiguity of simplicity bears directly on model selection. - Abstract: A system's perceived simplicity depends on whether it is represented classically or quantally. This is not so surprising, as classical and quantum physics are descriptive frameworks built on different assumptions that capture, emphasize, and express different properties and mechanisms. What is surprising is that, as we demonstrate, simplicity is ambiguous: the relative simplicity between two systems can change sign when moving between classical and quantum descriptions. Here, we associate simplicity with small model-memory. We see that the notions of absolute physical simplicity at best form a partial, not a total, order. This suggests that appeals to principles of physical simplicity, via Ockham's Razor or to the “elegance” of competing theories, may be fundamentally subjective. Recent rapid progress in quantum computation and quantum simulation suggest that the ambiguity of simplicity will strongly impact statistical inference and, in particular, model selection.

  9. Covariant representations of nuclear *-algebras

    International Nuclear Information System (INIS)

    Moore, S.M.

    1978-01-01

    Extensions of the Csup(*)-algebra theory for covariant representations to nuclear *-algebra are considered. Irreducible covariant representations are essentially unique, an invariant state produces a covariant representation with stable vacuum, and the usual relation between ergodic states and covariant representations holds. There exist construction and decomposition theorems and a possible relation between derivations and covariant representations

  10. The skew ray ambiguity in the analysis of videokeratoscopic data.

    Science.gov (United States)

    Iskander, D Robert; Davis, Brett A; Collins, Michael J

    2007-05-01

    Skew ray ambiguity is present in most videokeratoscopic measurements when azimuthal components of the corneal curvature are not taken into account. There have been some reported studies based on theoretical predictions and measured test surfaces suggesting that skew ray ambiguity is significant for highly deformed corneas or decentered corneal measurements. However, the effect of skew ray ambiguity in ray tracing through videokeratoscopic data has not been studied in depth. We have evaluated the significance of the skew ray ambiguity and its effect on the analyzed corneal optics. This has been achieved by devising a procedure in which we compared the corneal wavefront aberrations estimated from 3D ray tracing with those determined from 2D (meridional based) estimates of the refractive power. The latter was possible due to recently developed concept of refractive Zernike power polynomials which links the refractive power domain with that of the wavefront. Simulated corneal surfaces as well as data from a range of corneas (from two different Placido disk-based videokeratoscopes) were used to find the limit at which the difference in estimated corneal wavefronts (or the corresponding refractive powers) would have clinical significance (e.g., equivalent to 0.125 D or more). The inclusion/exclusion of the skew ray in the analyses showed some differences in the results. However, the proposed procedure showed clinically significant differences only for highly deformed corneas and only for large corneal diameters. For the overwhelming majority of surfaces, the skew ray ambiguity is not a clinically significant issue in the analysis of the videokeratoscopic data indicating that the meridional processing such as that encountered in calculation of the refractive power maps is adequate.

  11. AMBIGUITY IN AUTOBIGRAPHICAL NARRATIVES IN NIGERIA: VALORIZING SEXISM AND DISPLACEMENT IN OGONI COSMOLOGY

    Directory of Open Access Journals (Sweden)

    Christopher Babatunde Ogunyemi

    2016-12-01

    Full Text Available This paper focuses on the examination of ambiguity in autobiographical writings in Nigeria. It underscores the architectonic discourse, cultural alienation and ‘self-elevation’ in some selected autobiographies. Ambiguity in this instance visualizes that these male narratives hinge on something, which is what we now wish to excavate as an area of serious academic endeavour. And it also hinges on how Saro Wiwa’s autobiographies who happen to be male is inevitably sexist in orientation, this will, however, be shown when examining in particular the structuring (narratological devices of the texts. This work valorizes the cardinal representations of self and male gender in enhancing identity for people of diverse perspectives without appreciating female voices which constitute an integral part of the literary history and ideologue. ‘Negating women in art is negating history because history is the main discipline through which we can understand gender’ (Brereton, 1998, p. 17. This paper encapsulates the motif of dominance and oppression of women because women were only made to be seen and not heard or even represented in such art. However, this situation is disheartening because while the ‘African feminist accommodates men and make them its central assurance, love and care’ (Chukwuma, 1990, p. 15, men who are fickle minded literary ideologues delight in over projecting self using the instrument of ‘I’ in autobiographies without recourse to women who hold some basis to their existence. This research work entails a close analysis of the question of gender and displacement originating from these autobiographical writings originating from Nigeria and the configuration of the motif of metaphor in male dominated gender in five autobiographical writings in line with narratology and Butler’s Theory of performativity.

  12. A causal role for V5/MT neurons coding motion-disparity conjunctions in resolving perceptual ambiguity.

    Science.gov (United States)

    Krug, Kristine; Cicmil, Nela; Parker, Andrew J; Cumming, Bruce G

    2013-08-05

    Judgments about the perceptual appearance of visual objects require the combination of multiple parameters, like location, direction, color, speed, and depth. Our understanding of perceptual judgments has been greatly informed by studies of ambiguous figures, which take on different appearances depending upon the brain state of the observer. Here we probe the neural mechanisms hypothesized as responsible for judging the apparent direction of rotation of ambiguous structure from motion (SFM) stimuli. Resolving the rotation direction of SFM cylinders requires the conjoint decoding of direction of motion and binocular depth signals [1, 2]. Within cortical visual area V5/MT of two macaque monkeys, we applied electrical stimulation at sites with consistent multiunit tuning to combinations of binocular depth and direction of motion, while the monkey made perceptual decisions about the rotation of SFM stimuli. For both ambiguous and unambiguous SFM figures, rotation judgments shifted as if we had added a specific conjunction of disparity and motion signals to the stimulus elements. This is the first causal demonstration that the activity of neurons in V5/MT contributes directly to the perception of SFM stimuli and by implication to decoding the specific conjunction of disparity and motion, the two different visual cues whose combination drives the perceptual judgment. Copyright © 2013 The Authors. Published by Elsevier Inc. All rights reserved.

  13. Wind scatterometry with improved ambiguity selection and rain modeling

    Science.gov (United States)

    Draper, David Willis

    Although generally accurate, the quality of SeaWinds on QuikSCAT scatterometer ocean vector winds is compromised by certain natural phenomena and retrieval algorithm limitations. This dissertation addresses three main contributors to scatterometer estimate error: poor ambiguity selection, estimate uncertainty at low wind speeds, and rain corruption. A quality assurance (QA) analysis performed on SeaWinds data suggests that about 5% of SeaWinds data contain ambiguity selection errors and that scatterometer estimation error is correlated with low wind speeds and rain events. Ambiguity selection errors are partly due to the "nudging" step (initialization from outside data). A sophisticated new non-nudging ambiguity selection approach produces generally more consistent wind than the nudging method in moderate wind conditions. The non-nudging method selects 93% of the same ambiguities as the nudged data, validating both techniques, and indicating that ambiguity selection can be accomplished without nudging. Variability at low wind speeds is analyzed using tower-mounted scatterometer data. According to theory, below a threshold wind speed, the wind fails to generate the surface roughness necessary for wind measurement. A simple analysis suggests the existence of the threshold in much of the tower-mounted scatterometer data. However, the backscatter does not "go to zero" beneath the threshold in an uncontrolled environment as theory suggests, but rather has a mean drop and higher variability below the threshold. Rain is the largest weather-related contributor to scatterometer error, affecting approximately 4% to 10% of SeaWinds data. A simple model formed via comparison of co-located TRMM PR and SeaWinds measurements characterizes the average effect of rain on SeaWinds backscatter. The model is generally accurate to within 3 dB over the tropics. The rain/wind backscatter model is used to simultaneously retrieve wind and rain from SeaWinds measurements. The simultaneous

  14. Representations and Relations

    Czech Academy of Sciences Publication Activity Database

    Koťátko, Petr

    2014-01-01

    Roč. 21, č. 3 (2014), s. 282-302 ISSN 1335-0668 Institutional support: RVO:67985955 Keywords : representation * proposition * truth-conditions * belief-ascriptions * reference * externalism * fiction Subject RIV: AA - Philosophy ; Religion

  15. Wigner's Symmetry Representation Theorem

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 19; Issue 10. Wigner's Symmetry Representation Theorem: At the Heart of Quantum Field Theory! Aritra Kr Mukhopadhyay. General Article Volume 19 Issue 10 October 2014 pp 900-916 ...

  16. Boundary representation modelling techniques

    CERN Document Server

    2006-01-01

    Provides the most complete presentation of boundary representation solid modelling yet publishedOffers basic reference information for software developers, application developers and users Includes a historical perspective as well as giving a background for modern research.

  17. Polynomial representations of GLn

    CERN Document Server

    Green, James A; Erdmann, Karin

    2007-01-01

    The first half of this book contains the text of the first edition of LNM volume 830, Polynomial Representations of GLn. This classic account of matrix representations, the Schur algebra, the modular representations of GLn, and connections with symmetric groups, has been the basis of much research in representation theory. The second half is an Appendix, and can be read independently of the first. It is an account of the Littelmann path model for the case gln. In this case, Littelmann's 'paths' become 'words', and so the Appendix works with the combinatorics on words. This leads to the repesentation theory of the 'Littelmann algebra', which is a close analogue of the Schur algebra. The treatment is self- contained; in particular complete proofs are given of classical theorems of Schensted and Knuth.

  18. Polynomial representations of GLN

    CERN Document Server

    Green, James A

    1980-01-01

    The first half of this book contains the text of the first edition of LNM volume 830, Polynomial Representations of GLn. This classic account of matrix representations, the Schur algebra, the modular representations of GLn, and connections with symmetric groups, has been the basis of much research in representation theory. The second half is an Appendix, and can be read independently of the first. It is an account of the Littelmann path model for the case gln. In this case, Littelmann's 'paths' become 'words', and so the Appendix works with the combinatorics on words. This leads to the repesentation theory of the 'Littelmann algebra', which is a close analogue of the Schur algebra. The treatment is self- contained; in particular complete proofs are given of classical theorems of Schensted and Knuth.

  19. Using Social Media Derived Information to Reduce Ambiguity in Parcel Data

    Science.gov (United States)

    Sims, K.; Thakur, G.

    2017-12-01

    High-resolution spatiotemporal analyses often rely on the integration and harmonization of many unique data sources. Harmonized data can be especially useful in mobility/transportation planning, site selection/development planning, urban resiliency, sustainability, utility planning, and population modeling. However, even the most complete harmonized data sources can still possess gaps in their content, hindering their utility. For example, CoreLogic's ParcelPoint dataset is a nationwide collection of parcel points and polygons from nearly every U.S. county's local authority. While certain local land use parcel descriptions transfer easily to a national dataset, some do not, in part because of data ambiguity or regionality. This research will explore incorporating Points of Interest (POI) data derived from social media in order to reduce land use ambiguity in parcel data. Facebook, specifically, allows owners of businesses and institutions to create personalized pages with attributes like Name, Address, Location Type, Hours of Operation, Check-In counts, and designated latitude and longitude coordinates. These metadata can offer alternative land use descriptions and insights when it is otherwise not available, or when the land use associated with a parcel is not definitive. More importantly, this additional POI layer can allow for better representations of the places around us by providing a popularity and temporal aspect to the usual stagnant land use dataset. Furthermore, those responsible for emergency preparedness and response would benefit immensely from a more dynamic land use mapping opportunity. With that said, there are known limitations of social media data due to its volunteered nature. In order to recognize if the potential exists to overcome these limitations and use social-media-derived data to supplement national land use data, diverse study areas will be selected across the U.S. to yield a varied collection of POIs. Their Location Type will then be

  20. Perceived ambiguity as a barrier to intentions to learn genome sequencing results.

    Science.gov (United States)

    Taber, Jennifer M; Klein, William M P; Ferrer, Rebecca A; Han, Paul K J; Lewis, Katie L; Biesecker, Leslie G; Biesecker, Barbara B

    2015-10-01

    Many variants that could be returned from genome sequencing may be perceived as ambiguous-lacking reliability, credibility, or adequacy. Little is known about how perceived ambiguity influences thoughts about sequencing results. Participants (n = 494) in an NIH genome sequencing study completed a baseline survey before sequencing results were available. We examined how perceived ambiguity regarding sequencing results and individual differences in medical ambiguity aversion and tolerance for uncertainty were associated with cognitions and intentions concerning sequencing results. Perceiving sequencing results as more ambiguous was associated with less favorable cognitions about results and lower intentions to learn and share results. Among participants low in tolerance for uncertainty or optimism, greater perceived ambiguity was associated with lower intentions to learn results for non-medically actionable diseases; medical ambiguity aversion did not moderate any associations. Results are consistent with the phenomenon of "ambiguity aversion" and may influence whether people learn and communicate genomic information.

  1. Blunted Ambiguity Aversion During Cost-Benefit Decisions in Antisocial Individuals.

    Science.gov (United States)

    Buckholtz, Joshua W; Karmarkar, Uma; Ye, Shengxuan; Brennan, Grace M; Baskin-Sommers, Arielle

    2017-05-17

    Antisocial behavior is often assumed to reflect aberrant risk processing. However, many of the most significant forms of antisocial behavior, including crime, reflect the outcomes of decisions made under conditions of ambiguity rather than risk. While risk and ambiguity are formally distinct and experimentally dissociable, little is known about ambiguity sensitivity in individuals who engage in chronic antisocial behavior. We used a financial decision-making task in a high-risk community-based sample to test for associations between sensitivity to ambiguity, antisocial behavior, and arrest history. Sensitivity to ambiguity was lower in individuals who met diagnostic criteria for Antisocial Personality Disorder. Lower ambiguity sensitivity was also associated with higher externalizing (but not psychopathy) scores, and with higher levels of aggression (but not rule-breaking). Finally, blunted sensitivity to ambiguity also predicted a greater frequency of arrests. Together, these data suggest that alterations in cost-benefit decision-making under conditions of ambiguity may promote antisocial behavior.

  2. The impact of ambiguous economic news on uncertainty and consumer confidence

    NARCIS (Netherlands)

    Svensson, H.M.; Albæk, E.; van Dalen, A.; de Vreese, C.H.

    Journalistic practice emphasizes both positive and negative aspects of news stories. Nevertheless, the effects of ambiguous news, which includes both positive and negative information, are under-investigated. This study examines how exposure to ambiguous economic news affects uncertainty and

  3. Procedural Media Representation

    OpenAIRE

    Henrysson, Anders

    2002-01-01

    We present a concept for using procedural techniques to represent media. Procedural methods allow us to represent digital media (2D images, 3D environments etc.) with very little information and to render it photo realistically. Since not all kind of content can be created procedurally, traditional media representations (bitmaps, polygons etc.) must be used as well. We have adopted an object-based media representation where an object can be represented either with a procedure or with its trad...

  4. In defense of abstract conceptual representations.

    Science.gov (United States)

    Binder, Jeffrey R

    2016-08-01

    An extensive program of research in the past 2 decades has focused on the role of modal sensory, motor, and affective brain systems in storing and retrieving concept knowledge. This focus has led in some circles to an underestimation of the need for more abstract, supramodal conceptual representations in semantic cognition. Evidence for supramodal processing comes from neuroimaging work documenting a large, well-defined cortical network that responds to meaningful stimuli regardless of modal content. The nodes in this network correspond to high-level "convergence zones" that receive broadly crossmodal input and presumably process crossmodal conjunctions. It is proposed that highly conjunctive representations are needed for several critical functions, including capturing conceptual similarity structure, enabling thematic associative relationships independent of conceptual similarity, and providing efficient "chunking" of concept representations for a range of higher order tasks that require concepts to be configured as situations. These hypothesized functions account for a wide range of neuroimaging results showing modulation of the supramodal convergence zone network by associative strength, lexicality, familiarity, imageability, frequency, and semantic compositionality. The evidence supports a hierarchical model of knowledge representation in which modal systems provide a mechanism for concept acquisition and serve to ground individual concepts in external reality, whereas broadly conjunctive, supramodal representations play an equally important role in concept association and situation knowledge.

  5. There is a continuum ambiguity for elastic πN amplitudes

    International Nuclear Information System (INIS)

    Atkinson, D.; Roo, M. de; Polman, T.J.T.M.

    1984-01-01

    The implicit-function method of constructing phase-factor continuum ambiguities in phase-shift analysis is briefly reviewed, and new numerical examples are given of ambiguities in πN phase shifts at 1997 MeV. Since the ambiguous amplitudes differ by more than 5%, while the corresponding cross sections and polarizations are equal, to better than a computational accuracy of 0.007%, numerical credence is given to the theoretical claim that the continuum ambiguity exists. (orig.)

  6. Chains of phase-shift ambiguities in elastic spin-0-spin-1/2 scattering

    International Nuclear Information System (INIS)

    Berends, F.A.; Reisen, J.C.J.M. van

    1977-01-01

    It is shown, that a previously constructed phase-shift ambiguity for an arbitrary number, 2L + 1, of partial waves can be connected to L - 1 other ambiguities. The two sets of phase shifts defined by the chain of ambiguities become equal (modulo π) at the endpoints of the chain, but in general not at the endpoints of the ambiguities. Also other examples of such chains are given. (Auth.)

  7. Selective impairment of decision making under ambiguity in alexithymia.

    Science.gov (United States)

    Zhang, Lei; Wang, Xue; Zhu, Yu; Li, Hongchen; Zhu, Chunyan; Yu, Fengqiong; Wang, Kai

    2017-11-28

    Alexithymia is characterised by difficulties identifying and describing emotions. Few studies have investigated how alexithymia influences decision-making under different conditions (ambiguity and risk). This study aimed to examine whether alexithymia contributes to impairment in decision-making. This study included 42 participants with high scores in the Chinese version of Toronto Alexithymia Scale (alexithymia group), and 44 matched subjects with low scores (control group). Decision-making was measured using the Iowa Gambling Task (IGT) and the Game of Dice Task (GDT). The main findings of this study revealed selective deficits in IGT performance for the alexithymia group, while GDT performance was unimpaired when compared with the control group. In IGT, total netscores were lower for the alexithymia group compared to the control group, particularly with regard to block 5. Moreover, the alexithymia individuals selected significantly more adverse cards than the controls, indicating significant decision-making impairments. Alexithymia selectively influences decision-making under ambiguity.

  8. Resolution of potential ambiguities through farside angular structure: Semiclassical analysis

    International Nuclear Information System (INIS)

    Fricke, S.H.; Brandan, M.E.; McVoy, K.W.

    1988-01-01

    The optical potential fits summarized in the preceding paper are subjected to a semiclassical analysis of the Ford-Wheeler--Knoll-Schaeffer type. The important broad dips in their farside cross sections, which are essential in greatly reducing potential ambiguities, are found (in partial agreement with a suggestion of Goldberg's) to be mainly weak ''Airy'' or rainbow minima, that serve to identify deeply penetrating trajectories. The semiclassical analysis also permits the identification and understanding of a new category of discrete and continuous potential ambiguities, and suggests the manner in which specific features of the angular distributions (such as spacings and depths of various angular minima) determine the Woods-Saxon parameters found by a chi-squared search

  9. Resolving the range ambiguity in OFDR using digital signal processing

    International Nuclear Information System (INIS)

    Riesen, Nicolas; Lam, Timothy T-Y; Chow, Jong H

    2014-01-01

    A digitally range-gated variant of optical frequency domain reflectometry is demonstrated which overcomes the beat note ambiguity when sensing beyond a single frequency sweep. The range-gating is achieved using a spread spectrum technique involving time-stamping of the optical signal using high-frequency pseudorandom phase modulation. The reflections from different sections of fiber can then be isolated in the time domain by digitally inverting the phase modulation using appropriately-delayed copies of the pseudorandom noise code. Since the technique overcomes the range ambiguity in OFDR, it permits high sweep repetition rates without sacrificing range, thus allowing for high-bandwidth sensing over long lengths of fiber. This is demonstrated for the case of quasi-distributed sensing. (paper)

  10. Obstetricians' choice of cesarean delivery in ambiguous cases

    DEFF Research Database (Denmark)

    Fuglenes, Dorthe; Oian, Pål; Kristiansen, Ivar Sønbø

    2009-01-01

    OBJECTIVE: The aim of this study was to test the hypothesis that obstetricians' choice of delivery method is influenced by their risk attitude and perceived risk of complaints and malpractice litigation. STUDY DESIGN: The choice of delivery method in ambiguous cases was studied in a nationwide...... survey of Norwegian obstetricians (n = 716; response rate, 71%) using clinical scenarios. The risk attitude was measured by 6 items from the Jackson Personality Inventory-Revised. RESULTS: The proportion of obstetricians consenting to the cesarean request varied both within and across the scenarios....... The perceived risk of complaints and malpractice litigation was a clear determinant of obstetricians' choice of cesarean in all of the clinical scenarios, whereas no impact was observed for risk attitude. CONCLUSION: Obstetricians' judgments about cesarean request in ambiguous clinical cases vary considerably...

  11. Portfolio Management with Stochastic Interest Rates and Inflation Ambiguity

    DEFF Research Database (Denmark)

    Munk, Claus; Rubtsov, Alexey Vladimirovich

    We solve a stock-bond-cash portfolio choice problem for a risk- and ambiguity-averse investor in a setting where the inflation rate and interest rates are stochastic. The expected inflation rate is unobservable, but the investor may learn about it from realized inflation and observed stock and bond...... prices. The investor is aware that his model for the observed inflation is potentially misspecified, and he seeks an investment strategy that maximizes his expected utility from real terminal wealth and is also robust to inflation model misspecification. We solve the corresponding robust Hamilton......-Jacobi-Bellman equation in closed form and derive and illustrate a number of interesting properties of the solution. For example, ambiguity aversion affects the optimal portfolio through the correlation of price level with the stock index, a bond, and the expected inflation rate. Furthermore, unlike other settings...

  12. The ambiguity of simplicity in quantum and classical simulation

    Science.gov (United States)

    Aghamohammadi, Cina; Mahoney, John R.; Crutchfield, James P.

    2017-04-01

    A system's perceived simplicity depends on whether it is represented classically or quantally. This is not so surprising, as classical and quantum physics are descriptive frameworks built on different assumptions that capture, emphasize, and express different properties and mechanisms. What is surprising is that, as we demonstrate, simplicity is ambiguous: the relative simplicity between two systems can change sign when moving between classical and quantum descriptions. Here, we associate simplicity with small model-memory. We see that the notions of absolute physical simplicity at best form a partial, not a total, order. This suggests that appeals to principles of physical simplicity, via Ockham's Razor or to the ;elegance; of competing theories, may be fundamentally subjective. Recent rapid progress in quantum computation and quantum simulation suggest that the ambiguity of simplicity will strongly impact statistical inference and, in particular, model selection.

  13. Cancellation of renormalon ambiguities in the heavy quark effective theory

    International Nuclear Information System (INIS)

    Neubert, M.; Sachrajda, C.T.

    1995-01-01

    Recently, it has been shown that the concept of the pole mass of a heavy quark becomes ambiguous beyond perturbation theory, because of the presence of infrared renormalons. We argue that the predictions of the heavy quark effective theory, whose construction is based on the pole mass, are free of such ambiguities. In the 1/m Q expansion of physical quantities, infrared and ultraviolet renormalons compensate each other between coefficient functions and matrix elements. We trace the appearance of these compensations for current-induced exclusive heavy-to-heavy and heavy-to-light transitions, and for inclusive decays of heavy hadrons. In particular, we show that the structure of the heavy quark expansion is not obscured by renormalons, and none of the predictions of the heavy quark effective theory are invalidated. ((orig.))

  14. Instructor Strategic Ambiguity: Delineation of the Construct and Development of a Measure

    Science.gov (United States)

    Klyukovski, Andrei A.; Medlock-Klyukovski, Amanda L.

    2016-01-01

    This article presents research to delineate the construct of instructor strategic ambiguity (ISA) and develop a measure. The first study analyzed instructor uses of ambiguity, identified 18 strategies, and classified them into four categories. The second study developed an Instructor Strategic Ambiguity Measure (ISAM) for the college classroom.…

  15. The classification of ambiguity in polarimetric reconstruction of coronal mass ejection

    International Nuclear Information System (INIS)

    Dai, Xinghua; Wang, Huaning; Huang, Xin; Du, Zhanle; He, Han

    2014-01-01

    The Thomson scattering theory indicates that there exist explicit and implicit ambiguities in polarimetric analyses of coronal mass ejection (CME) observations. We suggest a classification for these ambiguities in CME reconstruction. Three samples, including double explicit, mixed, and double implicit ambiguity, are shown with the polarimetric analyses of STEREO CME observations. These samples demonstrate that this classification is helpful for improving polarimetric reconstruction.

  16. Performance management and goal ambiguity: managerial implications in a single payer system.

    Science.gov (United States)

    Calciolari, Stefano; Cantù, Elena; Fattore, Giovanni

    2011-01-01

    Goal ambiguity influences the effectiveness of performance management systems to drive organizations toward enhanced results. The literature analyzes the antecedents of goal ambiguity and shows the influence of goal ambiguity on the performance of U.S. federal agencies. However, no study has analyzed goal ambiguity in other countries or in health care systems. This study has three aims: to test the validity of a measurement instrument for goal ambiguity, to investigate its main antecedents, and to explore the relationship between goal ambiguity and organizational performance in a large, public, Beveridge-type health care system. A nationwide survey of general managers of the Italian national health system was performed. A factor analysis was used to validate the mono-dimensionality of an instrument that measured goal ambiguity. Structural equation modeling was used to test both the antecedents and the influence of goal ambiguity on organizational performance. Data from 135 health care organizations (53% response rate) were available for analysis. The results confirm the mono-dimensionality of the instrument, the existence of two environmental sources of ambiguity (political endorsement and governance commitment), and the negative relationship between goal ambiguity and organizational performance. Goal ambiguity matters because it may hamper organizational performance. Therefore, performance should be fostered by reducing goal ambiguity (e.g., goal-setting model, funding arrangements, and political support). Mutatis mutandis, our results may apply to public health care systems of other countries or other "public interest" sectors, such as social care and education.

  17. Estimating Ambiguity Preferences and Perceptions in Multiple Prior Models: Evidence from the Field

    NARCIS (Netherlands)

    S.G. Dimmock (Stephen); R.R.P. Kouwenberg (Roy); O.S. Mitchell (Olivia); K. Peijnenburg (Kim)

    2015-01-01

    markdownabstractWe develop a tractable method to estimate multiple prior models of decision-making under ambiguity. In a representative sample of the U.S. population, we measure ambiguity attitudes in the gain and loss domains. We find that ambiguity aversion is common for uncertain events of

  18. Identification and Definition of Lexically Ambiguous Words in Statistics by Tutors and Students

    Science.gov (United States)

    Richardson, Alice M.; Dunn, Peter K.; Hutchins, Rene

    2013-01-01

    Lexical ambiguity arises when a word from everyday English is used differently in a particular discipline, such as statistics. This paper reports on a project that begins by identifying tutors' perceptions of words that are potentially lexically ambiguous to students, in two different ways. Students' definitions of nine lexically ambiguous words…

  19. Differential age effects on lexical ambiguity resolution mechanisms

    OpenAIRE

    Lee, Chia-lin; Federmeier, Kara D.

    2010-01-01

    Multiple neurocognitive subsystems are involved in resolving lexical ambiguity under different circumstances. We examined how processing in these subsystems changes with normal aging by comparing ERP responses to homographs and unambiguous words completing congruent sentences (with both semantic and syntactic contextual information) or syntactic prose (syntactic information only). Like young adults in prior work, older adults elicited more negative N400s to homographs in congruent sentences, ...

  20. Cooperative Learning, Responsibility, Ambiguity, Controversy and Support in Motivating Students

    Directory of Open Access Journals (Sweden)

    Ronald Brecke, PhD

    2007-08-01

    Full Text Available This paper argues that student motivation is nurtured more by intrinsic rather than extrinsic rewards. Rather than relying on grades alone to stimulate students, this paper explores how engendering a natural critical learning environment can give students a sense of ownership in their own learning and lead to their commitment to that learning. We examine uses of cooperative learning, shared responsibility, ambiguity, controversy and support in student motivation.

  1. Cooperative Learning, Responsibility, Ambiguity, Controversy and Support in Motivating Students

    Directory of Open Access Journals (Sweden)

    Ronald Brecke

    2007-01-01

    Full Text Available This paper argues that student motivation is nurtured more by intrinsic rather than extrinsic rewards. Rather than relying on grades alone to stimulate students, this paper explores how engendering a natural critical learning environment can give students a sense of ownership in their own learning and lead to their commitment to that learning. We examine uses of cooperative learning, shared responsibility, ambiguity, controversy and support in student motivation.

  2. Knowledge representation and use. II. Representations

    Energy Technology Data Exchange (ETDEWEB)

    Lauriere, J L

    1982-03-01

    The use of computers is less and less restricted to numerical and data processing. On the other hand, current software mostly contains algorithms on universes with complete information. The paper discusses a different family of programs: expert systems are designed as aids in human reasoning in various specific areas. Symbolic knowledge manipulation, uncertain and incomplete deduction capabilities, natural communication with humans in non-procedural ways are their essential features. This part is mainly a reflection and a debate about the various modes of acquisition and representation of human knowledge. 32 references.

  3. Acute stress affects risk taking but not ambiguity aversion.

    Science.gov (United States)

    Buckert, Magdalena; Schwieren, Christiane; Kudielka, Brigitte M; Fiebach, Christian J

    2014-01-01

    Economic decisions are often made in stressful situations (e.g., at the trading floor), but the effects of stress on economic decision making have not been systematically investigated so far. The present study examines how acute stress influences economic decision making under uncertainty (risk and ambiguity) using financially incentivized lotteries. We varied the domain of decision making as well as the expected value of the risky prospect. Importantly, no feedback was provided to investigate risk taking and ambiguity aversion independent from learning processes. In a sample of 75 healthy young participants, 55 of whom underwent a stress induction protocol (Trier Social Stress Test for Groups), we observed more risk seeking for gains. This effect was restricted to a subgroup of participants that showed a robust cortisol response to acute stress (n = 26). Gambling under ambiguity, in contrast to gambling under risk, was not influenced by the cortisol response to stress. These results show that acute psychosocial stress affects economic decision making under risk, independent of learning processes. Our results further point to the importance of cortisol as a mediator of this effect.

  4. Pointwise Partial Information Decomposition Using the Specificity and Ambiguity Lattices

    Science.gov (United States)

    Finn, Conor; Lizier, Joseph

    2018-04-01

    What are the distinct ways in which a set of predictor variables can provide information about a target variable? When does a variable provide unique information, when do variables share redundant information, and when do variables combine synergistically to provide complementary information? The redundancy lattice from the partial information decomposition of Williams and Beer provided a promising glimpse at the answer to these questions. However, this structure was constructed using a much criticised measure of redundant information, and despite sustained research, no completely satisfactory replacement measure has been proposed. In this paper, we take a different approach, applying the axiomatic derivation of the redundancy lattice to a single realisation from a set of discrete variables. To overcome the difficulty associated with signed pointwise mutual information, we apply this decomposition separately to the unsigned entropic components of pointwise mutual information which we refer to as the specificity and ambiguity. This yields a separate redundancy lattice for each component. Then based upon an operational interpretation of redundancy, we define measures of redundant specificity and ambiguity enabling us to evaluate the partial information atoms in each lattice. These atoms can be recombined to yield the sought-after multivariate information decomposition. We apply this framework to canonical examples from the literature and discuss the results and the various properties of the decomposition. In particular, the pointwise decomposition using specificity and ambiguity satisfies a chain rule over target variables, which provides new insights into the so-called two-bit-copy example.

  5. Dressed skeleton expansion and the coupling scale ambiguity problem

    International Nuclear Information System (INIS)

    Lu, Hung Jung.

    1992-09-01

    Perturbative expansions in quantum field theories are usually expressed in powers of a coupling constant. In principle, the infinite sum of the expansion series is independent of the renormalization scale of the coupling constant. In practice, there is a remnant dependence of the truncated series on the renormalization scale. This scale ambiguity can severely restrict the predictive power of theoretical calculations. The dressed skeleton expansion is developed as a calculational method which avoids the coupling scale ambiguity problem. In this method, physical quantities are expressed as functional expansions in terms of a coupling vertex function. The arguments of the vertex function are given by the physical momenta of each process. These physical momenta effectively replace the unspecified renormalization scale and eliminate the ambiguity problem. This method is applied to various field theoretical models and its main features and limitations are explored. For quantum chromodynamics, an expression for the running coupling constant of the three-gluon vertex is obtained. The effective coupling scale of this vertex is shown to be essentially given by μ 2 ∼ Q min 2 Q med 2 /Q max 2 where Q min 2 Q med 2 /Q max 2 are respectively the smallest, the next-to-smallest and the largest scale among the three gluon virtualities. This functional form suggests that the three-gluon vertex becomes non-perturbative at asymmetric momentum configurations. Implications for four-jet physics is discussed

  6. Robustness of climate metrics under climate policy ambiguity

    International Nuclear Information System (INIS)

    Ekholm, Tommi; Lindroos, Tomi J.; Savolainen, Ilkka

    2013-01-01

    Highlights: • We assess the economic impacts of using different climate metrics. • The setting is cost-efficient scenarios for three interpretations of the 2C target. • With each target setting, the optimal metric is different. • Therefore policy ambiguity prevents the selection of an optimal metric. • Robust metric values that perform well with multiple policy targets however exist. -- Abstract: A wide array of alternatives has been proposed as the common metrics with which to compare the climate impacts of different emission types. Different physical and economic metrics and their parameterizations give diverse weights between e.g. CH 4 and CO 2 , and fixing the metric from one perspective makes it sub-optimal from another. As the aims of global climate policy involve some degree of ambiguity, it is not possible to determine a metric that would be optimal and consistent with all policy aims. This paper evaluates the cost implications of using predetermined metrics in cost-efficient mitigation scenarios. Three formulations of the 2 °C target, including both deterministic and stochastic approaches, shared a wide range of metric values for CH 4 with which the mitigation costs are only slightly above the cost-optimal levels. Therefore, although ambiguity in current policy might prevent us from selecting an optimal metric, it can be possible to select robust metric values that perform well with multiple policy targets

  7. Inherent ambiguities in the determination of phase-shifts

    International Nuclear Information System (INIS)

    Atkinson, D.

    1975-01-01

    The observables in an elastic scattering process are unchanged if all the scattering amplitudes are multiplied by the same angle-dependent phase. The non-spin-flip and spin-flip amplitudes remain unchanged by the substitution: g(cos theta)→g(cos theta)exp[i phi(cos theta)] and h(cos theta)→h(cos theta)exp[i phi(cos theta)]. Unless some extra and hoc assumption is made, there is a continuum ambiguity, which has been explored some time ago, with specific models for the phase phi by members of the Birmingham group. In the ordinary quantum mechanics of scattering, one writes a wave-function asymptotically as psi(r - ) approximately esup(ikr costheta)+f(cos theta)esup(ikr)/r where f is the scattering amplitude. The ambiguity which is a change in the phase of the scattering amplitude, and thus of the scattered part of the wavefunction, but with no change of the first term in (the unscattered plane wave coming along the z-axis is discussed in detail. Preliminary results in the energy-range 1550-1750 MeV cm and their implications are given. Argand plots of ambiguities at various energies are presented. (K.B.)

  8. Teaching weight to explicitly address language ambiguities and conceptual difficulties

    Science.gov (United States)

    Taibu, Rex; Schuster, David; Rudge, David

    2017-06-01

    Language ambiguities in concept meanings can exacerbate student learning difficulties and conceptual understanding of physics concepts. This is especially true for the concept of "weight," which has multiple meanings in both scientific and everyday usage. The term weight has been defined in several different ways, with nuances, but in textbooks and teaching the term is almost always defined in one of two ways: operationally either as the contact force between an object and a measuring scale or as the gravitational force on an object due to some other body such as Earth. The use of the same name for different concepts leads to much confusion, especially in accelerating situations, and to conflicting notions of "weightlessness" in free fall situations. In the present paper, we share an innovative approach that initially avoids the term weight entirely while teaching the physics of each situation, and then teaches the language ambiguities explicitly. We developed an instructional module with this approach and implemented it over two terms in three sections of an introductory physics course for preservice elementary teachers. Learning gains for content understanding were assessed using pretests and post-tests. Participants achieved remarkably high gains for both static and accelerating situations. Surveys pre- and postinstruction showed substantially improved appreciation of language issues and ambiguities associated with weight, weightlessness, and free fall. Interviews with instructors teaching the module provided additional insight into the advantages and teaching demands of the new approach.

  9. Cross-linguistic scope ambiguity: When two systems meet

    Directory of Open Access Journals (Sweden)

    Gregory Scontras

    2017-04-01

    Full Text Available Accurately recognizing and resolving ambiguity is a hallmark of linguistic ability. English is a language with scope ambiguities in doubly-quantified sentences like 'A shark ate every pirate'; this sentence can either describe a scenario with a single shark eating all of the pirates, or a scenario with many sharks—a potentially-different one eating each pirate. In Mandarin Chinese, the corresponding sentence is unambiguous, as it can only describe the single-shark scenario. We present experimental evidence to this effect, comparing native speakers of English with native speakers of Mandarin in their interpretations of doubly-quantified sentences. Having demonstrated the difference between these two languages in their ability for inverse scope interpretations, we then probe the robustness of the grammar of scope by extending our experiments to English-dominant adult heritage speakers of Mandarin. Like native speakers of Mandarin, heritage Mandarin speakers lack inverse scope in Mandarin. Crucially, these speakers also lack inverse scope in English, their dominant language in adulthood. We interpret these results as evidence for the pressure to simplify the grammar of scope, decreasing ambiguity when possible. In other words, when two systems meet—as in the case of heritage speakers—the simpler system prevails. This article is part of the special collection: Quantifier Scope

  10. Operator representations of frames

    DEFF Research Database (Denmark)

    Christensen, Ole; Hasannasab, Marzieh

    2017-01-01

    of the properties of the operator T requires more work. For example it is a delicate issue to obtain a representation with a bounded operator, and the availability of such a representation not only depends on the frame considered as a set, but also on the chosen indexing. Using results from operator theory we show......The purpose of this paper is to consider representations of frames {fk}k∈I in a Hilbert space ℋ of the form {fk}k∈I = {Tkf0}k∈I for a linear operator T; here the index set I is either ℤ or ℒ0. While a representation of this form is available under weak conditions on the frame, the analysis...... that by embedding the Hilbert space ℋ into a larger Hilbert space, we can always represent a frame via iterations of a bounded operator, composed with the orthogonal projection onto ℋ. The paper closes with a discussion of an open problem concerning representations of Gabor frames via iterations of a bounded...

  11. Peripersonal space in the brain.

    Science.gov (United States)

    di Pellegrino, Giuseppe; Làdavas, Elisabetta

    2015-01-01

    Research in neuroscience reveals that the brain constructs multiple representation of space. Here, we primarily focus on peripersonal space (PPS) representation, the region of space immediately surrounding our bodies and in which objects can be grasped and manipulated. We review convergent results from several generations of studies, including neurophysiological studies in animals, neuropsychological investigations in monkeys and brain-damaged patients with spatial cognition disorders, as well as recent neuroimaging experiments in neurologically normal individuals. Collectively, these studies show that the primate brain constructs multiple, rapidly modifiable representations of space, centered on different body parts (i.e., hand-centered, head-centered, and trunk-centered), which arise through extensive multisensory interactions within a set of interconnected parietal and frontal regions. PPS representations are pivotal in the sensory guidance of motor behavior, allowing us to interact with objects and, as demonstrated by recent studies, with other people in the space around us. Copyright © 2014 Elsevier Ltd. All rights reserved.

  12. Representation Elements of Spatial Thinking

    Science.gov (United States)

    Fiantika, F. R.

    2017-04-01

    This paper aims to add a reference in revealing spatial thinking. There several definitions of spatial thinking but it is not easy to defining it. We can start to discuss the concept, its basic a forming representation. Initially, the five sense catch the natural phenomenon and forward it to memory for processing. Abstraction plays a role in processing information into a concept. There are two types of representation, namely internal representation and external representation. The internal representation is also known as mental representation; this representation is in the human mind. The external representation may include images, auditory and kinesthetic which can be used to describe, explain and communicate the structure, operation, the function of the object as well as relationships. There are two main elements, representations properties and object relationships. These elements play a role in forming a representation.

  13. Mobilities and Representations

    DEFF Research Database (Denmark)

    Thelle, Mikkel

    2017-01-01

    to consider how they and their peers are currently confronting representations of mobility. This is particularly timely given the growing academic focus on practices, material mediation, and nonrepresentational theories, as well as on bodily reactions, emotions, and feelings that, according to those theories......As the centerpiece of the eighth T2M yearbook, the following interview about representations of mobility signals a new and exciting focus area for Mobility in History. In future issues we hope to include reviews that grapple more with how mobilities have been imagined and represented in the arts......, literature, and film. Moreover, we hope the authors of future reviews will reflect on the ways they approached those representations. Such commentaries would provide valuable methodological insights, and we hope to begin that effort with this interview. We have asked four prominent mobility scholars...

  14. Memetics of representation

    Directory of Open Access Journals (Sweden)

    Roberto De Rubertis

    2012-06-01

    Full Text Available This article will discuss about the physiological genesis of representation and then it will illustrate the developments, especially in evolutionary perspective, and it will show how these are mainly a result of accidental circumstances, rather than of deliberate intention of improvement. In particular, it will be argue that the representation has behaved like a meme that has arrived to its own progressive evolution coming into symbiosis with the different cultures in which it has spread, and using in this activity human work “unconsciously”. Finally it will be shown how in this action the geometry is an element key, linked to representation both to construct images using graphics operations and to erect buildings using concrete operations.

  15. Post-representational cartography

    Directory of Open Access Journals (Sweden)

    Rob Kitchin

    2010-03-01

    Full Text Available Over the past decade there has been a move amongst critical cartographers to rethink maps from a post-representational perspective – that is, a vantage point that does not privilege representational modes of thinking (wherein maps are assumed to be mirrors of the world and automatically presumes the ontological security of a map as a map, but rather rethinks and destabilises such notions. This new theorisation extends beyond the earlier critiques of Brian Harley (1989 that argued maps were social constructions. For Harley a map still conveyed the truth of a landscape, albeit its message was bound within the ideological frame of its creator. He thus advocated a strategy of identifying the politics of representation within maps in order to circumnavigate them (to reveal the truth lurking underneath, with the ontology of cartographic practice remaining unquestioned.

  16. Introduction to computer data representation

    CERN Document Server

    Fenwick, Peter

    2014-01-01

    Introduction to Computer Data Representation introduces readers to the representation of data within computers. Starting from basic principles of number representation in computers, the book covers the representation of both integer and floating point numbers, and characters or text. It comprehensively explains the main techniques of computer arithmetic and logical manipulation. The book also features chapters covering the less usual topics of basic checksums and 'universal' or variable length representations for integers, with additional coverage of Gray Codes, BCD codes and logarithmic repre

  17. Representation Discovery using Harmonic Analysis

    CERN Document Server

    Mahadevan, Sridhar

    2008-01-01

    Representations are at the heart of artificial intelligence (AI). This book is devoted to the problem of representation discovery: how can an intelligent system construct representations from its experience? Representation discovery re-parameterizes the state space - prior to the application of information retrieval, machine learning, or optimization techniques - facilitating later inference processes by constructing new task-specific bases adapted to the state space geometry. This book presents a general approach to representation discovery using the framework of harmonic analysis, in particu

  18. Decision-Making under Ambiguity Is Modulated by Visual Framing, but Not by Motor vs. Non-Motor Context. Experiments and an Information-Theoretic Ambiguity Model.

    Science.gov (United States)

    Grau-Moya, Jordi; Ortega, Pedro A; Braun, Daniel A

    2016-01-01

    A number of recent studies have investigated differences in human choice behavior depending on task framing, especially comparing economic decision-making to choice behavior in equivalent sensorimotor tasks. Here we test whether decision-making under ambiguity exhibits effects of task framing in motor vs. non-motor context. In a first experiment, we designed an experience-based urn task with varying degrees of ambiguity and an equivalent motor task where subjects chose between hitting partially occluded targets. In a second experiment, we controlled for the different stimulus design in the two tasks by introducing an urn task with bar stimuli matching those in the motor task. We found ambiguity attitudes to be mainly influenced by stimulus design. In particular, we found that the same subjects tended to be ambiguity-preferring when choosing between ambiguous bar stimuli, but ambiguity-avoiding when choosing between ambiguous urn sample stimuli. In contrast, subjects' choice pattern was not affected by changing from a target hitting task to a non-motor context when keeping the stimulus design unchanged. In both tasks subjects' choice behavior was continuously modulated by the degree of ambiguity. We show that this modulation of behavior can be explained by an information-theoretic model of ambiguity that generalizes Bayes-optimal decision-making by combining Bayesian inference with robust decision-making under model uncertainty. Our results demonstrate the benefits of information-theoretic models of decision-making under varying degrees of ambiguity for a given context, but also demonstrate the sensitivity of ambiguity attitudes across contexts that theoretical models struggle to explain.

  19. Decision-Making under Ambiguity Is Modulated by Visual Framing, but Not by Motor vs. Non-Motor Context. Experiments and an Information-Theoretic Ambiguity Model.

    Directory of Open Access Journals (Sweden)

    Jordi Grau-Moya

    Full Text Available A number of recent studies have investigated differences in human choice behavior depending on task framing, especially comparing economic decision-making to choice behavior in equivalent sensorimotor tasks. Here we test whether decision-making under ambiguity exhibits effects of task framing in motor vs. non-motor context. In a first experiment, we designed an experience-based urn task with varying degrees of ambiguity and an equivalent motor task where subjects chose between hitting partially occluded targets. In a second experiment, we controlled for the different stimulus design in the two tasks by introducing an urn task with bar stimuli matching those in the motor task. We found ambiguity attitudes to be mainly influenced by stimulus design. In particular, we found that the same subjects tended to be ambiguity-preferring when choosing between ambiguous bar stimuli, but ambiguity-avoiding when choosing between ambiguous urn sample stimuli. In contrast, subjects' choice pattern was not affected by changing from a target hitting task to a non-motor context when keeping the stimulus design unchanged. In both tasks subjects' choice behavior was continuously modulated by the degree of ambiguity. We show that this modulation of behavior can be explained by an information-theoretic model of ambiguity that generalizes Bayes-optimal decision-making by combining Bayesian inference with robust decision-making under model uncertainty. Our results demonstrate the benefits of information-theoretic models of decision-making under varying degrees of ambiguity for a given context, but also demonstrate the sensitivity of ambiguity attitudes across contexts that theoretical models struggle to explain.

  20. Decision-Making under Ambiguity Is Modulated by Visual Framing, but Not by Motor vs. Non-Motor Context. Experiments and an Information-Theoretic Ambiguity Model

    Science.gov (United States)

    Grau-Moya, Jordi; Ortega, Pedro A.; Braun, Daniel A.

    2016-01-01

    A number of recent studies have investigated differences in human choice behavior depending on task framing, especially comparing economic decision-making to choice behavior in equivalent sensorimotor tasks. Here we test whether decision-making under ambiguity exhibits effects of task framing in motor vs. non-motor context. In a first experiment, we designed an experience-based urn task with varying degrees of ambiguity and an equivalent motor task where subjects chose between hitting partially occluded targets. In a second experiment, we controlled for the different stimulus design in the two tasks by introducing an urn task with bar stimuli matching those in the motor task. We found ambiguity attitudes to be mainly influenced by stimulus design. In particular, we found that the same subjects tended to be ambiguity-preferring when choosing between ambiguous bar stimuli, but ambiguity-avoiding when choosing between ambiguous urn sample stimuli. In contrast, subjects’ choice pattern was not affected by changing from a target hitting task to a non-motor context when keeping the stimulus design unchanged. In both tasks subjects’ choice behavior was continuously modulated by the degree of ambiguity. We show that this modulation of behavior can be explained by an information-theoretic model of ambiguity that generalizes Bayes-optimal decision-making by combining Bayesian inference with robust decision-making under model uncertainty. Our results demonstrate the benefits of information-theoretic models of decision-making under varying degrees of ambiguity for a given context, but also demonstrate the sensitivity of ambiguity attitudes across contexts that theoretical models struggle to explain. PMID:27124723

  1. Development of a New Scale to Measure Ambiguity Tolerance in Veterinary Students.

    Science.gov (United States)

    Hammond, Jennifer A; Hancock, Jason; Martin, Margaret S; Jamieson, Susan; Mellor, Dominic J

    The ability to cope with ambiguity and feelings of uncertainty is an essential part of professional practice. Research with physicians has identified that intolerance of ambiguity or uncertainty is linked to stress, and some authors have hypothesized that there could be an association between intolerance of ambiguity and burnout. We describe the adaptation of the TAMSAD (Tolerance of Ambiguity in Medical Students and Doctors) scale for use with veterinary students. Exploratory factor analysis supports a uni-dimensional structure for the Ambiguity tolerance construct. Although internal reliability of the 29-item TAMSAD scale is reasonable (α=.50), an alternative 27-item scale (drawn from the original 41 items used to develop TAMSAD) shows higher internal reliability for veterinary students (α=.67). We conclude that there is good evidence to support the validity of this latter TAVS (Tolerance of Ambiguity in Veterinary Students) scale to study ambiguity tolerance in veterinary students.

  2. A method of undifferenced ambiguity resolution for GPS+GLONASS precise point positioning.

    Science.gov (United States)

    Yi, Wenting; Song, Weiwei; Lou, Yidong; Shi, Chuang; Yao, Yibin

    2016-05-25

    Integer ambiguity resolution is critical for achieving positions of high precision and for shortening the convergence time of precise point positioning (PPP). However, GLONASS adopts the signal processing technology of frequency division multiple access and results in inter-frequency code biases (IFCBs), which are currently difficult to correct. This bias makes the methods proposed for GPS ambiguity fixing unsuitable for GLONASS. To realize undifferenced GLONASS ambiguity fixing, we propose an undifferenced ambiguity resolution method for GPS+GLONASS PPP, which considers the IFCBs estimation. The experimental result demonstrates that the success rate of GLONASS ambiguity fixing can reach 75% through the proposed method. Compared with the ambiguity float solutions, the positioning accuracies of ambiguity-fixed solutions of GLONASS-only PPP are increased by 12.2%, 20.9%, and 10.3%, and that of the GPS+GLONASS PPP by 13.0%, 35.2%, and 14.1% in the North, East and Up directions, respectively.

  3. Ambiguity and Investment Decisions: An Empirical Analysis on Mutual Fund Investor Behaviour

    Directory of Open Access Journals (Sweden)

    Chao Tang

    2017-09-01

    Full Text Available The paper empirically studies the relationship between ambiguity and mutual fund investor behaviour. Theoretical models for investment decisions incorporating ambiguity motivate our analyses. While the models indicate that investors would less likely to invest in financial markets when ambiguity increases, there is rare empirical evidence in natural occurring financial data to examine this hypothesis. In this paper, we test the hypothesis with equity fund flow data as for investment decisions and ambiguity with the degree of disagreement in equity analysts’ prediction about asset returns. Our results support the hypothesis that increases in ambiguity could lead to less fund flows and this result remains consistently when adding various control variables affecting fund flows. Besides, we find that heterogeneous impacts of ambiguity: equity funds with high yield targets and active management style are affected more than funds investing in stable stocks; funds with larger proportion of institutional investors are more sensitive and affected by the ambiguity.

  4. Additive and polynomial representations

    CERN Document Server

    Krantz, David H; Suppes, Patrick

    1971-01-01

    Additive and Polynomial Representations deals with major representation theorems in which the qualitative structure is reflected as some polynomial function of one or more numerical functions defined on the basic entities. Examples are additive expressions of a single measure (such as the probability of disjoint events being the sum of their probabilities), and additive expressions of two measures (such as the logarithm of momentum being the sum of log mass and log velocity terms). The book describes the three basic procedures of fundamental measurement as the mathematical pivot, as the utiliz

  5. On the spinor representation

    Energy Technology Data Exchange (ETDEWEB)

    Hoff da Silva, J.M.; Rogerio, R.J.B. [Universidade Estadual Paulista, Departamento de Fisica e Quimica, Guaratingueta, SP (Brazil); Villalobos, C.H.C. [Universidade Estadual Paulista, Departamento de Fisica e Quimica, Guaratingueta, SP (Brazil); Universidade Federal Fluminense, Instituto de Fisica, Niteroi, RJ (Brazil); Rocha, Roldao da [Universidade Federal do ABC-UFABC, Centro de Matematica, Computacao e Cognicao, Santo Andre (Brazil)

    2017-07-15

    A systematic study of the spinor representation by means of the fermionic physical space is accomplished and implemented. The spinor representation space is shown to be constrained by the Fierz-Pauli-Kofink identities among the spinor bilinear covariants. A robust geometric and topological structure can be manifested from the spinor space, wherein the first and second homotopy groups play prominent roles on the underlying physical properties, associated to fermionic fields. The mapping that changes spinor fields classes is then exemplified, in an Einstein-Dirac system that provides the spacetime generated by a fermion. (orig.)

  6. Combined GPS/GLONASS Precise Point Positioning with Fixed GPS Ambiguities

    Science.gov (United States)

    Pan, Lin; Cai, Changsheng; Santerre, Rock; Zhu, Jianjun

    2014-01-01

    Precise point positioning (PPP) technology is mostly implemented with an ambiguity-float solution. Its performance may be further improved by performing ambiguity-fixed resolution. Currently, the PPP integer ambiguity resolutions (IARs) are mainly based on GPS-only measurements. The integration of GPS and GLONASS can speed up the convergence and increase the accuracy of float ambiguity estimates, which contributes to enhancing the success rate and reliability of fixing ambiguities. This paper presents an approach of combined GPS/GLONASS PPP with fixed GPS ambiguities (GGPPP-FGA) in which GPS ambiguities are fixed into integers, while all GLONASS ambiguities are kept as float values. An improved minimum constellation method (MCM) is proposed to enhance the efficiency of GPS ambiguity fixing. Datasets from 20 globally distributed stations on two consecutive days are employed to investigate the performance of the GGPPP-FGA, including the positioning accuracy, convergence time and the time to first fix (TTFF). All datasets are processed for a time span of three hours in three scenarios, i.e., the GPS ambiguity-float solution, the GPS ambiguity-fixed resolution and the GGPPP-FGA resolution. The results indicate that the performance of the GPS ambiguity-fixed resolutions is significantly better than that of the GPS ambiguity-float solutions. In addition, the GGPPP-FGA improves the positioning accuracy by 38%, 25% and 44% and reduces the convergence time by 36%, 36% and 29% in the east, north and up coordinate components over the GPS-only ambiguity-fixed resolutions, respectively. Moreover, the TTFF is reduced by 27% after adding GLONASS observations. Wilcoxon rank sum tests and chi-square two-sample tests are made to examine the significance of the improvement on the positioning accuracy, convergence time and TTFF. PMID:25237901

  7. Combined GPS/GLONASS Precise Point Positioning with Fixed GPS Ambiguities

    Directory of Open Access Journals (Sweden)

    Lin Pan

    2014-09-01

    Full Text Available Precise point positioning (PPP technology is mostly implemented with an ambiguity-float solution. Its performance may be further improved by performing ambiguity-fixed resolution. Currently, the PPP integer ambiguity resolutions (IARs are mainly based on GPS-only measurements. The integration of GPS and GLONASS can speed up the convergence and increase the accuracy of float ambiguity estimates, which contributes to enhancing the success rate and reliability of fixing ambiguities. This paper presents an approach of combined GPS/GLONASS PPP with fixed GPS ambiguities (GGPPP-FGA in which GPS ambiguities are fixed into integers, while all GLONASS ambiguities are kept as float values. An improved minimum constellation method (MCM is proposed to enhance the efficiency of GPS ambiguity fixing. Datasets from 20 globally distributed stations on two consecutive days are employed to investigate the performance of the GGPPP-FGA, including the positioning accuracy, convergence time and the time to first fix (TTFF. All datasets are processed for a time span of three hours in three scenarios, i.e., the GPS ambiguity-float solution, the GPS ambiguity-fixed resolution and the GGPPP-FGA resolution. The results indicate that the performance of the GPS ambiguity-fixed resolutions is significantly better than that of the GPS ambiguity-float solutions. In addition, the GGPPP-FGA improves the positioning accuracy by 38%, 25% and 44% and reduces the convergence time by 36%, 36% and 29% in the east, north and up coordinate components over the GPS-only ambiguity-fixed resolutions, respectively. Moreover, the TTFF is reduced by 27% after adding GLONASS observations. Wilcoxon rank sum tests and chi-square two-sample tests are made to examine the significance of the improvement on the positioning accuracy, convergence time and TTFF.

  8. Going beyond representational anthropology

    DEFF Research Database (Denmark)

    Winther, Ida Wentzel

    Going beyond representational anthropology: Re-presenting bodily, emotional and virtual practices in everyday life. Separated youngsters and families in Greenland Greenland is a huge island, with a total of four high-schools. Many youngsters (age 16-18) move far away from home in order to get...

  9. Reflection on Political Representation

    DEFF Research Database (Denmark)

    Kusche, Isabel

    2017-01-01

    This article compares how Members of Parliament in the United Kingdom and Ireland reflect on constituency service as an aspect of political representation. It differs from existing research on the constituency role of MPs in two regards. First, it approaches the question from a sociological viewp...

  10. Social representations about cancer

    Directory of Open Access Journals (Sweden)

    Andreja Cirila Škufca

    2003-09-01

    Full Text Available In this article we are presenting the results of the comparison study on social representations and causal attributions about cancer. We compared a breast cancer survivors group and control group without own experience of cancer of their own. Although social representations about cancer differ in each group, they are closely related to the concept of suffering, dying and death. We found differences in causal attribution of cancer. In both groups we found a category of risky behavior, which attributes a responsibility for a disease to an individual. Besides these factors we found predominate stress and psychological influences in cancer survivors group. On the other hand control group indicated factors outside the ones control e.g. heredity and environmental factors. Representations about a disease inside person's social space are important in co-shaping the individual process of coping with own disease. Since these representations are not always coherent with the knowledge of modern medicine their knowledge and appreciation in the course of treatment is of great value. We find the findingss of applied social psychology important as starting points in the therapeutic work with patients.

  11. The Problem of Representation

    Science.gov (United States)

    Tervo, Juuso

    2012-01-01

    In "Postphysical Vision: Art Education's Challenge in an Age of Globalized Aesthetics (AMondofesto)" (2008) and "Beyond Aesthetics: Returning Force and Truth to Art and Its Education" (2009), jan jagodzinski argued for politics that go "beyond" representation--a project that radically questions visual culture…

  12. Women and political representation.

    Science.gov (United States)

    Rathod, P B

    1999-01-01

    A remarkable progress in women's participation in politics throughout the world was witnessed in the final decade of the 20th century. According to the Inter-Parliamentary Union report, there were only eight countries with no women in their legislatures in 1998. The number of women ministers at the cabinet level worldwide doubled in a decade, and the number of countries without any women ministers dropped from 93 to 48 during 1987-96. However, this progress is far from satisfactory. Political representation of women, minorities, and other social groups is still inadequate. This may be due to a complex combination of socioeconomic, cultural, and institutional factors. The view that women's political participation increases with social and economic development is supported by data from the Nordic countries, where there are higher proportions of women legislators than in less developed countries. While better levels of socioeconomic development, having a women-friendly political culture, and higher literacy are considered favorable factors for women's increased political representation, adopting one of the proportional representation systems (such as a party-list system, a single transferable vote system, or a mixed proportional system with multi-member constituencies) is the single factor most responsible for the higher representation of women.

  13. In Praise of Vagueness: Uncertainty, ambiguity and archaeological methodology

    DEFF Research Database (Denmark)

    Sørensen, Tim Flohr

    2016-01-01

    This article stipulates that vagueness is a socially important yet academically largely overlooked aspect of human interaction with the world. Vagueness and vague experiences can structure material categorisations of the world; it can contribute to the shaping of social relations and nurture...... and ambiguity can be integral to certain social and material phenomena. Third, the article examines recent archaeological analyses of burial practices in South Scandinavian passage graves from the Middle Neolithic in order to discuss the pursuit of certitude in archaeological observations and interpretations...

  14. SAR antenna design for ambiguity and multipath suppression

    DEFF Research Database (Denmark)

    Christensen, Erik Lintz; Dich, Mikael

    1993-01-01

    A high resolution airborne synthetic aperture radar (SAR) has been developed at the Electromagnetics Institute (EMI) for remote sensing applications. The paper considers the radiation of antennas for a SAR system from a systems perspective. The basic specifications of an idealised antenna...... are obtained from the required swath and the azimuth footprint needed for the SAR processing. The radiation from a real antenna causes unwanted signal returns that lead to intensity variations (multipath) and ghost echoes (ambiguity). Additional specifications are deduced by considering these signals...

  15. Sibling jealousy and aesthetic ambiguity in Austen's Pride and Prejudice.

    Science.gov (United States)

    Hanly, Margaret Ann Fitzpatrick

    2009-04-01

    Jane Austen's most popular novel, Pride and Prejudice (1813), illuminates and is illuminated by psychoanalytic aesthetics. When Austen dramatizes unconscious oedipal/sibling rivalries, irony acts as a type of aesthetic ambiguity (E. Kris 1952). A psychoanalytic perspective shows that Austen uses a grammar of negatives (negation, denial, minimization) to achieve the dual meanings of irony, engaging the reader's unconscious instinctual satisfactions, while at the same time protecting the reader from unpleasant affects. Austen's plot, which portrays regressions driven by sibling jealousy, reveals that a new tolerance of remorse and depression in her heroine and hero leads to psychic growth.

  16. CSR and the Mediated Emergence of Strategic Ambiguity

    DEFF Research Database (Denmark)

    Guthey, Eric; Morsing, Mette

    2014-01-01

    expect CSR to conform to varying degrees of both formal and substantive rationality. These diverse expectations conflict with each other and change over time. A content analysis of press coverage in Denmark suggests that the business media reflect and amplify the ambiguity generated by these shifting......, not from the direct intentions of individual stakeholders. Our framework suggests that CSR is best understood not as a clear or consistent agenda, but rather as a forum for sensemaking, diversity of opinion, and debate over the conflicting social norms and expectations attached to corporate activity....

  17. Sensorimotor Adaptation Following Exposure to Ambiguous Inertial Motion Cues

    Science.gov (United States)

    Wood, S. J.; Clement, G. R.; Rupert, A. H.; Reschke, M. F.; Harm, D. L.; Guedry, F. E.

    2007-01-01

    The central nervous system must resolve the ambiguity of inertial motion sensory cues in order to derive accurate spatial orientation awareness. Adaptive changes in how inertial cues from the otolith system are integrated with other sensory information lead to perceptual and postural disturbances upon return to Earth s gravity. The primary goals of this ground-based research investigation are to explore physiological mechanisms and operational implications of tilt-translation disturbances during and following re-entry, and to evaluate a tactile prosthesis as a countermeasure for improving control of whole-body orientation during tilt and translation motion.

  18. Discrete ambiguity resolution and baryon-resonance parameter determination

    International Nuclear Information System (INIS)

    Chew, D.M; Urban, M.

    1978-04-01

    A partial-wave analysis was performed on elastic π + p data between 1400 and 2200 MeV, using principles of analyticity (to select and amalgamate data), causality and unitarity together with Barrelet zeros are the resonating waves between 1500 and 1800 MeV examined in detail, and it is shown how a new resolution of the discrete ambiguity gives, for the S31 and D33 resonances, different parameters than found in an earlier resolution using less accurate information. In either case, mass degeneracy of these resonances is observed in agreement with general considerations regarding smooth zero trajectories. 18 references

  19. Role of MRI in the evaluation of ambiguous genitalia

    Energy Technology Data Exchange (ETDEWEB)

    Secaf, E [Dept. of Radiology, Univ. of California School of Medicine, San Francisco, CA (United States) Dept. de Radiologia, Faculdade de Medicina da Univ. de Sao Paulo (Brazil); Hricak, H [Dept. of Radiology, Univ. of California School of Medicine, San Francisco, CA (United States) Dept. of Urology, Univ. of California School of Medicine, San Francisco, CA (United States); Gooding, C A [Dept. of Radiology, Univ. of California School of Medicine, San Francisco, CA (United States) Dept. of Pediatrics, Univ. of California School of Medicine, San Francisco, CA (United States); Ho, V W [Dept. of Radiology, Univ. of California School of Medicine, San Francisco, CA (United States); Gorczyca, D P [Dept. of Radiology, Univ. of California School of Medicine, San Francisco, CA (United States) Dept. of Radiology, Univ. of California, Los Angeles, CA (United States); Ringertz, H [Dept. of Diagnostic Radiology, Karolinska Hospital, Stockholm (Sweden); Conte, F A [Dept. of Pediatr

    1994-08-01

    Diagnostic accuracy of magnetic resonance imaging (MRI) interpretation was assessed prospectively in patients with ambiguous genitalia or intersex problems. MRI depiction of the uterus was possible in 93 %, the vagina in 95 %, the penis in 100 %, the testis in 88 %, and the ovary in 74 % of patients. The strength of MRI lies in the multiplanar capability and tissue characterization by means of T1- and T2-weighted sequences. MRI contributes to accurate morphologic evaluation of muellerian duct structures, the gonads, and the development of the phallus, all of which are essential for appropriate gender assignment and planning of surgical reconstruction. (orig.)

  20. Projection Effects and Strategic Ambiguity in Electoral Competition

    DEFF Research Database (Denmark)

    Jensen, Thomas

    Theories from psychology suggest that voters' perceptions of political positions depend on their non-policy related attitudes towards the candidates. A voter who likes (dislikes) a candidate will perceive the candidate's position as closer to (further from) his own than it really is. This is called...... projection. If voters' perceptions are not counterfactual and voting is based on perceived policy positions then projection gives a generally liked candidate an incentive to be ambiguous. In this paper we construct and analyze a formal model to investigate under which conditions this incentive survives...

  1. Projection effects and strategic ambiguity in electoral competition

    DEFF Research Database (Denmark)

    Jensen, Thomas

    2009-01-01

    Theories from psychology suggest that voters' perceptions of political positions depend on their non-policy related attitudes towards the candidates. A voter who likes (dislikes) a candidate will perceive the candidate's position as closer to (further from) his own than it really is. This is called...... projection. If voters' perceptions are not counterfactual and voting is based on perceived policy positions then projection gives generally liked candidates an incentive to be ambiguous. In this paper we extend the standard Downsian model in order to investigate under what conditions this incentive survives...

  2. New Hamiltonians for loop quantum cosmology with arbitrary spin representations

    Science.gov (United States)

    Ben Achour, Jibril; Brahma, Suddhasattwa; Geiller, Marc

    2017-04-01

    In loop quantum cosmology, one has to make a choice of SU(2) irreducible representation in which to compute holonomies and regularize the curvature of the connection. The systematic choice made in the literature is to work in the fundamental representation, and very little is known about the physics associated with higher spin labels. This constitutes an ambiguity of which the understanding, we believe, is fundamental for connecting loop quantum cosmology to full theories of quantum gravity like loop quantum gravity, its spin foam formulation, or cosmological group field theory. We take a step in this direction by providing here a new closed formula for the Hamiltonian of flat Friedmann-Lemaître-Robertson-Walker models regularized in a representation of arbitrary spin. This expression is furthermore polynomial in the basic variables which correspond to well-defined operators in the quantum theory, takes into account the so-called inverse-volume corrections, and treats in a unified way two different regularization schemes for the curvature. After studying the effective classical dynamics corresponding to single and multiple-spin Hamiltonians, we study the behavior of the critical density when the number of representations is increased and the stability of the difference equations in the quantum theory.

  3. Mapping brain function to brain anatomy

    International Nuclear Information System (INIS)

    Valentino, D.J.; Huang, H.K.; Mazziotta, J.C.

    1988-01-01

    In Imaging the human brain, MRI is commonly used to reveal anatomical structure, while PET is used to reveal tissue function. This paper presents a protocol for correlating data between these two imaging modalities; this correlation can provide in vivo regional measurements of brain function which are essential to our understanding of the human brain. The authors propose a general protocol to standardize the acquisition and analysis of functional image data. First, MR and PET images are collected to form three-dimensional volumes of structural and functional image data. Second, these volumes of image data are corrected for distortions inherent in each imaging modality. Third, the image volumes are correlated to provide correctly aligned structural and functional images. The functional images are then mapped onto the structural images in both two-dimensional and three-dimensional representations. Finally, morphometric techniques can be used to provide statistical measures of the structure and function of the human brain

  4. The Language Faculty - mind or brain?

    DEFF Research Database (Denmark)

    Thrane, Torben

    2009-01-01

    I. Dretske. Apart from a brief introduction and a conclusion, the paper contains 5 main sections: Three levels of Chomskyan linguistics, Representational theories of mind, Representational systems, Representational architecture, and finally The language faculty in brain studies.......The paper subjects Chomsky's compound creation - the 'mind/brain' - to scrutiny. It argues that it creates a slipway for talk about the human language faculty,  such that what should properly be discussed in functional terms - what the brain does when processing language - is instead talked about...

  5. Resolution of ambiguities in cartoons as an illustration of the role of pragmatics in natural language understanding by computers

    Energy Technology Data Exchange (ETDEWEB)

    Mazlack, L.J.; Paz, N.M.

    1983-01-01

    Newspaper cartoons can graphically display the result of ambiguity in human speech; the result can be unexpected and funny. Likewise, computer analysis of natural language statements also needs to successfully resolve ambiguous situations. Computer techniques already developed use restricted world knowledge in resolving ambiguous language use. This paper illustrates how these techniques can be used in resolving ambiguous situations arising in cartoons. 8 references.

  6. From expert generalists to ambiguity masters: using ambiguity tolerance theory to redefine the practice of rural nurses.

    Science.gov (United States)

    Knight, Kaye; Kenny, Amanda; Endacott, Ruth

    2016-06-01

    To redefine the practice of rural nurses and describe a model that conceptualises the capabilities and characteristics required in the rural environment. The way in which the practice of rural nurses has been conceptualised is problematic. Definitions of rural nursing have been identified primarily through the functional context of rural health service delivery. The expert generalist term has provided a foundation theory for rural nurses with understandings informed by the scope of practice needed to meet service delivery requirements. However, authors exploring intrinsic characteristics of rural nurses have challenged this definition, as it does not adequately address the deeper, intangible complexities of practice required in the rural context. Despite this discourse, an alternative way to articulate the distinctive nature of rural nursing practice has eluded authors in Australia and internationally. A theoretical paper based on primary research. The development of the model was informed by the findings of a study that explored the nursing practice of managing telephone presentations in rural health services in Victoria, Australia. The study involved policy review from State and Federal governments, nursing and medical professional bodies, and five rural health services; semi-structured interviews with eight Directors of Nursing, seven registered nurses and focus group interviews with eight registered nurses. An ambiguity tolerance model drawn from corporate global entrepreneurship theory was adapted to explain the findings of the study. The adapted model presents capabilities and characteristics used by nurses to successfully manage the ambiguity of providing care in the rural context. Redefining the practice of rural nurses, through an adapted theory of ambiguity tolerance, highlights nursing characteristics and capabilities required in the rural context. This perspective offers new ways of thinking about the work of rural nurses, rural nurse policy, education

  7. Artificial limb representation in amputees.

    Science.gov (United States)

    van den Heiligenberg, Fiona M Z; Orlov, Tanya; Macdonald, Scott N; Duff, Eugene P; Henderson Slater, David; Beckmann, Christian F; Johansen-Berg, Heidi; Culham, Jody C; Makin, Tamar R

    2018-05-01

    The human brain contains multiple hand-selective areas, in both the sensorimotor and visual systems. Could our brain repurpose neural resources, originally developed for supporting hand function, to represent and control artificial limbs? We studied individuals with congenital or acquired hand-loss (hereafter one-handers) using functional MRI. We show that the more one-handers use an artificial limb (prosthesis) in their everyday life, the stronger visual hand-selective areas in the lateral occipitotemporal cortex respond to prosthesis images. This was found even when one-handers were presented with images of active prostheses that share the functionality of the hand but not necessarily its visual features (e.g. a 'hook' prosthesis). Further, we show that daily prosthesis usage determines large-scale inter-network communication across hand-selective areas. This was demonstrated by increased resting state functional connectivity between visual and sensorimotor hand-selective areas, proportional to the intensiveness of everyday prosthesis usage. Further analysis revealed a 3-fold coupling between prosthesis activity, visuomotor connectivity and usage, suggesting a possible role for the motor system in shaping use-dependent representation in visual hand-selective areas, and/or vice versa. Moreover, able-bodied control participants who routinely observe prosthesis usage (albeit less intensively than the prosthesis users) showed significantly weaker associations between degree of prosthesis observation and visual cortex activity or connectivity. Together, our findings suggest that altered daily motor behaviour facilitates prosthesis-related visual processing and shapes communication across hand-selective areas. This neurophysiological substrate for prosthesis embodiment may inspire rehabilitation approaches to improve usage of existing substitutionary devices and aid implementation of future assistive and augmentative technologies.

  8. Psychoanalytic and musical ambiguity: the tritone in gee, officer krupke.

    Science.gov (United States)

    Jaffee Nagel, Julie

    2010-02-01

    The poignant and timeless Broadway musical West Side Story is viewed from the standpoint of taking musical forms as psychoanalytic data. The musical configuration of notes called the tritone (or diabolus in musica) is taken as a sonic metaphor expressing ambiguity both in musical vocabulary and in mental life. The tritone, which historically and harmonically represents instability, is heard throughout the score and emphasizes the intrapsychic, interpersonal, and social dramas that unfold within and between the two gangs in West Side Story. Particular emphasis is given to the comic but exceedingly sober song Gee, Officer Krupke. Bernstein's sensitivity to the ambiguity and tension inherent in the tritone in West Side Story is conceptualized as an intersection of music theory and theories of mind; this perspective holds implications for clinical practice and transports psychoanalytic concepts from the couch to the Broadway stage and into the community to address the complexities of love, hate, aggression, prejudice, and violence. Ultimately, West Side Story cross-pollinates music and theater, as well as music and psychoanalytic concepts.

  9. Ambivalence and Ambiguity in The Autobiography of Miss Jane Pittman

    Directory of Open Access Journals (Sweden)

    Monica Michlin

    2006-05-01

    Full Text Available This close reading of the text highlights how Miss Jane, in her double role as protagonist and narrator, shows considerable ambivalence towards friend and foe alike, with the result that the apparently transparent ideological meaning of entire episodes is blurred by what some critics have merely put down to “conservatism.” I examine Miss Jane’s almost constant suppression of emotion, and frequent displays of ambivalence towards other black people; her ambiguous relationship to oppressive, but familiar whites like Albert Cluveau or Robert Samson; and her conflicted relation to black heroes and heroics. Is the leading character a variation on the “mammy” who has internalized racist figures of speech, and uses contradictory images that undermine black heroics and validate white oppression? Or is Gaines’s point to undo the “retrick” of heroics and of alienation alike, and, against of backdrop of constant, ordinary destruction of black lives, to cast the adult Miss Jane as a Brer Rabbit-like figure, for whom survival and resistance are both dialectically connected and opposed? Is there a contradiction between her “progress” towards resistance shown in the last section, and her metadiscursive comments in the present, and does her literally walking out of her own story give a conclusive meaning to her narrative, or does it point to the author’s not having been able to resolve the ambivalence and ambiguities within the text?

  10. Speech rhythm facilitates syntactic ambiguity resolution: ERP evidence.

    Directory of Open Access Journals (Sweden)

    Maria Paula Roncaglia-Denissen

    Full Text Available In the current event-related potential (ERP study, we investigated how speech rhythm impacts speech segmentation and facilitates the resolution of syntactic ambiguities in auditory sentence processing. Participants listened to syntactically ambiguous German subject- and object-first sentences that were spoken with either regular or irregular speech rhythm. Rhythmicity was established by a constant metric pattern of three unstressed syllables between two stressed ones that created rhythmic groups of constant size. Accuracy rates in a comprehension task revealed that participants understood rhythmically regular sentences better than rhythmically irregular ones. Furthermore, the mean amplitude of the P600 component was reduced in response to object-first sentences only when embedded in rhythmically regular but not rhythmically irregular context. This P600 reduction indicates facilitated processing of sentence structure possibly due to a decrease in processing costs for the less-preferred structure (object-first. Our data suggest an early and continuous use of rhythm by the syntactic parser and support language processing models assuming an interactive and incremental use of linguistic information during language processing.

  11. Speech rhythm facilitates syntactic ambiguity resolution: ERP evidence.

    Science.gov (United States)

    Roncaglia-Denissen, Maria Paula; Schmidt-Kassow, Maren; Kotz, Sonja A

    2013-01-01

    In the current event-related potential (ERP) study, we investigated how speech rhythm impacts speech segmentation and facilitates the resolution of syntactic ambiguities in auditory sentence processing. Participants listened to syntactically ambiguous German subject- and object-first sentences that were spoken with either regular or irregular speech rhythm. Rhythmicity was established by a constant metric pattern of three unstressed syllables between two stressed ones that created rhythmic groups of constant size. Accuracy rates in a comprehension task revealed that participants understood rhythmically regular sentences better than rhythmically irregular ones. Furthermore, the mean amplitude of the P600 component was reduced in response to object-first sentences only when embedded in rhythmically regular but not rhythmically irregular context. This P600 reduction indicates facilitated processing of sentence structure possibly due to a decrease in processing costs for the less-preferred structure (object-first). Our data suggest an early and continuous use of rhythm by the syntactic parser and support language processing models assuming an interactive and incremental use of linguistic information during language processing.

  12. Radiological Evaluation of Ambiguous Genitalia with Various Imaging Modalities

    Science.gov (United States)

    Ravi, N.; Bindushree, Kadakola

    2012-07-01

    Disorders of sex development (DSDs) are congenital conditions in which the development of chromosomal, gonadal, or anatomic sex is atypical. These can be classified broadly into four categories on the basis of gonadal histologic features: female pseudohermaphroditism (46,XX with two ovaries); male pseudohermaphroditism (46,XY with two testes); true hermaphroditism (ovotesticular DSD) (both ovarian and testicular tissues); and gonadal dysgenesis, either mixed (a testis and a streak gonad) or pure (bilateral streak gonads). Imaging plays an important role in demonstrating the anatomy and associated anomalies. Ultrasonography is the primary modality for demonstrating internal organs and magnetic resonance imaging is used as an adjunct modality to assess for internal gonads and genitalia. Early and appropriate gender assignment is necessary for healthy physical and psychologic development of children with ambiguous genitalia. Gender assignment can be facilitated with a team approach that involves a pediatric endocrinologist, geneticist, urologist, psychiatrist, social worker, neonatologist, nurse, and radiologist, allowing timely diagnosis and proper management. We describe case series on ambiguous genitalia presented to our department who were evaluated with multiple imaging modalities.

  13. Standard model of knowledge representation

    Science.gov (United States)

    Yin, Wensheng

    2016-09-01

    Knowledge representation is the core of artificial intelligence research. Knowledge representation methods include predicate logic, semantic network, computer programming language, database, mathematical model, graphics language, natural language, etc. To establish the intrinsic link between various knowledge representation methods, a unified knowledge representation model is necessary. According to ontology, system theory, and control theory, a standard model of knowledge representation that reflects the change of the objective world is proposed. The model is composed of input, processing, and output. This knowledge representation method is not a contradiction to the traditional knowledge representation method. It can express knowledge in terms of multivariate and multidimensional. It can also express process knowledge, and at the same time, it has a strong ability to solve problems. In addition, the standard model of knowledge representation provides a way to solve problems of non-precision and inconsistent knowledge.

  14. Constructing visual representations

    DEFF Research Database (Denmark)

    Huron, Samuel; Jansen, Yvonne; Carpendale, Sheelagh

    2014-01-01

    tangible building blocks. We learned that all participants, most of whom had little experience in visualization authoring, were readily able to create and talk about their own visualizations. Based on our observations, we discuss participants’ actions during the development of their visual representations......The accessibility of infovis authoring tools to a wide audience has been identified as a major research challenge. A key task in the authoring process is the development of visual mappings. While the infovis community has long been deeply interested in finding effective visual mappings......, comparatively little attention has been placed on how people construct visual mappings. In this paper, we present the results of a study designed to shed light on how people transform data into visual representations. We asked people to create, update and explain their own information visualizations using only...

  15. Naturalising Representational Content

    Science.gov (United States)

    Shea, Nicholas

    2014-01-01

    This paper sets out a view about the explanatory role of representational content and advocates one approach to naturalising content – to giving a naturalistic account of what makes an entity a representation and in virtue of what it has the content it does. It argues for pluralism about the metaphysics of content and suggests that a good strategy is to ask the content question with respect to a variety of predictively successful information processing models in experimental psychology and cognitive neuroscience; and hence that data from psychology and cognitive neuroscience should play a greater role in theorising about the nature of content. Finally, the contours of the view are illustrated by drawing out and defending a surprising consequence: that individuation of vehicles of content is partly externalist. PMID:24563661

  16. Knowledge Representation and Ontologies

    Science.gov (United States)

    Grimm, Stephan

    Knowledge representation and reasoning aims at designing computer systems that reason about a machine-interpretable representation of the world. Knowledge-based systems have a computational model of some domain of interest in which symbols serve as surrogates for real world domain artefacts, such as physical objects, events, relationships, etc. [1]. The domain of interest can cover any part of the real world or any hypothetical system about which one desires to represent knowledge for com-putational purposes. A knowledge-based system maintains a knowledge base, which stores the symbols of the computational model in the form of statements about the domain, and it performs reasoning by manipulating these symbols. Applications can base their decisions on answers to domain-relevant questions posed to a knowledge base.

  17. Europe representations in textbooks

    OpenAIRE

    Brennetot , Arnaud

    2011-01-01

    This EuroBroadMap working paper presents an analysis of textbooks dealing with the representations of Europe and European Union. In most of these textbooks from secondary school, the teaching of the geography of Europe precedes the evocation of the EU. Europe is often depicted as a given object, reduced to a number of structural aspects (relief, climate, demography, traditional cultures, economic activities, etc.) whose only common point is their location within conventional boundaries. Such ...

  18. Non-Representational Theory

    DEFF Research Database (Denmark)

    Jensen, Ole B.

    2016-01-01

    Dette kapitel gennemgår den såkaldte ”Non-Representational Theory” (NRT), der primært er kendt fra den Angelsaksiske humangeografi, og som særligt er blevet fremført af den engelske geograf Nigel Thrift siden midten af 2000 årtiet. Da positionen ikke kan siges at være specielt homogen vil kapitlet...

  19. Harmonic Analysis and Group Representation

    CERN Document Server

    Figa-Talamanca, Alessandro

    2011-01-01

    This title includes: Lectures - A. Auslander, R. Tolimeri - Nilpotent groups and abelian varieties, M Cowling - Unitary and uniformly bounded representations of some simple Lie groups, M. Duflo - Construction de representations unitaires d'un groupe de Lie, R. Howe - On a notion of rank for unitary representations of the classical groups, V.S. Varadarajan - Eigenfunction expansions of semisimple Lie groups, and R. Zimmer - Ergodic theory, group representations and rigidity; and, Seminars - A. Koranyi - Some applications of Gelfand pairs in classical analysis.

  20. Functional representations for quantized fields

    International Nuclear Information System (INIS)

    Jackiw, R.

    1988-01-01

    This paper provides information on Representing transformations in quantum theory bosonic quantum field theories: Schrodinger Picture; Represnting Transformations in Bosonic Quantum Field Theory; Two-Dimensional Conformal Transformations, Schrodinger picture representation, Fock space representation, Inequivalent Schrodinger picture representations; Discussion, Self-Dual and Other Models; Field Theory in de Sitter Space. Fermionic Quantum Field Theories: Schroedinger Picture; Schrodinger Picture Representation for Two-Dimensional; Conformal Transformations; Fock Space Dynamics in the Schrodinger Picture; Fock Space Evaluation of Anomalous Current and Conformal Commutators

  1. A Range Ambiguity Suppression Processing Method for Spaceborne SAR with Up and Down Chirp Modulation

    Directory of Open Access Journals (Sweden)

    Xuejiao Wen

    2018-05-01

    Full Text Available Range ambiguity is one of the factors which affect the SAR image quality. Alternately transmitting up and down chirp modulation pulses is one of the methods used to suppress the range ambiguity. However, the defocusing range ambiguous signal can still hold the stronger backscattering intensity than the mainlobe imaging area in some case, which has a severe impact on visual effects and subsequent applications. In this paper, a novel hybrid range ambiguity suppression method for up and down chirp modulation is proposed. The method can obtain the ambiguity area image and reduce the ambiguity signal power appropriately, by applying pulse compression using a contrary modulation rate and CFAR detecting method. The effectiveness and correctness of the approach is demonstrated by processing the archive images acquired by Chinese Gaofen-3 SAR sensor in full-polarization mode.

  2. A Range Ambiguity Suppression Processing Method for Spaceborne SAR with Up and Down Chirp Modulation.

    Science.gov (United States)

    Wen, Xuejiao; Qiu, Xiaolan; Han, Bing; Ding, Chibiao; Lei, Bin; Chen, Qi

    2018-05-07

    Range ambiguity is one of the factors which affect the SAR image quality. Alternately transmitting up and down chirp modulation pulses is one of the methods used to suppress the range ambiguity. However, the defocusing range ambiguous signal can still hold the stronger backscattering intensity than the mainlobe imaging area in some case, which has a severe impact on visual effects and subsequent applications. In this paper, a novel hybrid range ambiguity suppression method for up and down chirp modulation is proposed. The method can obtain the ambiguity area image and reduce the ambiguity signal power appropriately, by applying pulse compression using a contrary modulation rate and CFAR detecting method. The effectiveness and correctness of the approach is demonstrated by processing the archive images acquired by Chinese Gaofen-3 SAR sensor in full-polarization mode.

  3. PENGARUH ROLE AMBIGUITY DAN ROLE CONFLICT TERHADAP KOMITMEN INDEPENDENSI AUDITOR INTERNAL

    Directory of Open Access Journals (Sweden)

    Angga Prasetyo

    2011-05-01

    Full Text Available This study aims to determine the influence of role conflict (role conflict against the commitmentof internal auditors’ independence, and know the effect of role ambiguity (role ambiguity ofthe Internal Auditor independence commitment. Data was collected through primary method byusing a questionnaire. Then performed the data analysis that includes classical assumption test,F test, t test, and analysis of coefficient of determination (R2. To analyze using SPSS softwareversion 16. Based on research result shows that role conflict has a significant negative effect oncommitment to the independence of internal auditors, and role ambiguity (role ambiguity has asignificant negative effect on commitment to the independence of internal auditors. While basedon simultaneous test (F test, role conflict (role conflict and role ambiguity (role ambiguity havean influence on the commitment of internal auditor independence.

  4. Pioneers of representation theory

    CERN Document Server

    Curtis, Charles W

    1999-01-01

    The year 1897 was marked by two important mathematical events: the publication of the first paper on representations of finite groups by Ferdinand Georg Frobenius (1849-1917) and the appearance of the first treatise in English on the theory of finite groups by William Burnside (1852-1927). Burnside soon developed his own approach to representations of finite groups. In the next few years, working independently, Frobenius and Burnside explored the new subject and its applications to finite group theory. They were soon joined in this enterprise by Issai Schur (1875-1941) and some years later, by Richard Brauer (1901-1977). These mathematicians' pioneering research is the subject of this book. It presents an account of the early history of representation theory through an analysis of the published work of the principals and others with whom the principals' work was interwoven. Also included are biographical sketches and enough mathematics to enable readers to follow the development of the subject. An introductor...

  5. Cohen-Macaulay representations

    CERN Document Server

    Leuschke, Graham J

    2012-01-01

    This book is a comprehensive treatment of the representation theory of maximal Cohen-Macaulay (MCM) modules over local rings. This topic is at the intersection of commutative algebra, singularity theory, and representations of groups and algebras. Two introductory chapters treat the Krull-Remak-Schmidt Theorem on uniqueness of direct-sum decompositions and its failure for modules over local rings. Chapters 3-10 study the central problem of classifying the rings with only finitely many indecomposable MCM modules up to isomorphism, i.e., rings of finite CM type. The fundamental material--ADE/simple singularities, the double branched cover, Auslander-Reiten theory, and the Brauer-Thrall conjectures--is covered clearly and completely. Much of the content has never before appeared in book form. Examples include the representation theory of Artinian pairs and Burban-Drozd's related construction in dimension two, an introduction to the McKay correspondence from the point of view of maximal Cohen-Macaulay modules, Au...

  6. A 2.5-D Representation of the Human Hand

    Science.gov (United States)

    Longo, Matthew R.; Haggard, Patrick

    2012-01-01

    Primary somatosensory maps in the brain represent the body as a discontinuous, fragmented set of two-dimensional (2-D) skin regions. We nevertheless experience our body as a coherent three-dimensional (3-D) volumetric object. The links between these different aspects of body representation, however, remain poorly understood. Perceiving the body's…

  7. Perceptual and categorical decision making: goal-relevant representation of two domains at different levels of abstraction.

    Science.gov (United States)

    Shankar, Swetha; Kayser, Andrew S

    2017-06-01

    To date it has been unclear whether perceptual decision making and rule-based categorization reflect activation of similar cognitive processes and brain regions. On one hand, both map potentially ambiguous stimuli to a smaller set of motor responses. On the other hand, decisions about perceptual salience typically concern concrete sensory representations derived from a noisy stimulus, while categorization is typically conceptualized as an abstract decision about membership in a potentially arbitrary set. Previous work has primarily examined these types of decisions in isolation. Here we independently varied salience in both the perceptual and categorical domains in a random dot-motion framework by manipulating dot-motion coherence and motion direction relative to a category boundary, respectively. Behavioral and modeling results suggest that categorical (more abstract) information, which is more relevant to subjects' decisions, is weighted more strongly than perceptual (more concrete) information, although they also have significant interactive effects on choice. Within the brain, BOLD activity within frontal regions strongly differentiated categorical salience and weakly differentiated perceptual salience; however, the interaction between these two factors activated similar frontoparietal brain networks. Notably, explicitly evaluating feature interactions revealed a frontal-parietal dissociation: parietal activity varied strongly with both features, but frontal activity varied with the combined strength of the information that defined the motor response. Together, these data demonstrate that frontal regions are driven by decision-relevant features and argue that perceptual decisions and rule-based categorization reflect similar cognitive processes and activate similar brain networks to the extent that they define decision-relevant stimulus-response mappings. NEW & NOTEWORTHY Here we study the behavioral and neural dynamics of perceptual categorization when

  8. SAR Cross-Ambiguities in SAOCOM-CS Large Baseline Bistatic Configuration

    OpenAIRE

    Bordoni, Federica; Rodriguez-Cassola, Marc; Younis, Marwan; Prats-Iraola, Pau; Lopez-Dekker, Paco; Krieger, Gerhard

    2016-01-01

    The evaluation of the ambiguous signal level, the Ambiguity-to-Signal Ratio (ASR), plays a key role in the Synthetic Aperture Radar (SAR) design and performance prediction. In conventional SAR acquisition scenarios, the computation of the ASR is based on the evaluation of the range and azimuth ambiguous contributes. Though appealing for its simplicity, this approach could be inaccurate in case of complex SAR acquisition geometries. In this paper we focus on the ASR performance of the SAOCOM-...

  9. Pericentric Inversion of Chromosome 9 in an Infant With Ambiguous Genitalia.

    Science.gov (United States)

    Sotoudeh, Arya; Rostami, Parastoo; Nakhaeimoghadam, Maryam; Mohsenipour, Reihaneh; Rezaei, Nima

    2017-10-01

    Pericentric inversion of Chromosome 9 is one of the most common chromosomal abnormalities, which could be associated with various manifestations in some cases. Herein, a patient is presented with ambiguous genitalia that karyotyping revealed pericentric inversion of Chromosome 9 (p12,q13). Pericentric inversion of Chromosome 9 could be considered in the list of differential diagnosis of those with ambiguous genitalia, while chromosomal karyotype and culture could be recommended in children with ambiguous genitalia.

  10. In Command And Out Of Control: Leaders Developing Teams That Thrive In Chaos And Ambiguity

    Science.gov (United States)

    2016-05-26

    In Command and Out of Control: Leaders Developing Teams that Thrive in Chaos and Ambiguity A Monograph by...TITLE AND SUBTITLE Sa. CONTRACT NUMBER In Command and Out of Control: Leaders Developing Teams that Thrive in Chaos and Ambiguity Sb. GRANT NUMBER...the chaos and ambiguity associated with war. Teams must provide the innovative and creative solutions formerly left to the individual leader. This

  11. Translation norms for English and Spanish: The role of lexical variables, word class, and L2 proficiency in negotiating translation ambiguity

    Science.gov (United States)

    Prior, Anat; MacWhinney, Brian; Kroll, Judith F.

    2014-01-01

    We present a set of translation norms for 670 English and 760 Spanish nouns, verbs and class ambiguous items that varied in their lexical properties in both languages, collected from 80 bilingual participants. Half of the words in each language received more than a single translation across participants. Cue word frequency and imageability were both negatively correlated with number of translations. Word class predicted number of translations: Nouns had fewer translations than did verbs, which had fewer translations than class-ambiguous items. The translation probability of specific responses was positively correlated with target word frequency and imageability, and with its form overlap with the cue word. Translation choice was modulated by L2 proficiency: Less proficient bilinguals tended to produce lower probability translations than more proficient bilinguals, but only in forward translation, from L1 to L2. These findings highlight the importance of translation ambiguity as a factor influencing bilingual representation and performance. The norms can also provide an important resource to assist researchers in the selection of experimental materials for studies of bilingual and monolingual language performance. These norms may be downloaded from www.psychonomic.org/archive. PMID:18183923

  12. Downsizing and reorganization: demands, challenges and ambiguity for registered nurses.

    Science.gov (United States)

    Hertting, Anna; Nilsson, Kerstin; Theorell, Töres; Larsson, Ullabeth Sätterlund

    2004-01-01

    The 1990s were characterized by substantial financial cuts, and related staff redundancies and reorganizations in the Swedish health care sector. A large hospital in Sweden was selected for the study, in which downsizing had occurred between 1995 and 1997. The number of staff in the hospital was reduced by an average of 20%, and 10% were relocated to other departments. The aims of this study were to explore registered nurses' experiences of psychosocial 'stressors' and 'motivators', and how they handled their work situations, following a period of personnel reductions and ongoing reorganization. Interviews were undertaken with 14 nurses working in one Swedish hospital. Nurses were interviewed in 1997 about the recent and last round of redundancies, and were followed up 1 year later in 1998 and again in 2001. Interviews were audiotaped, transcribed and analysed for thematic content. Five themes emerged in relation to nurses' perceived stressors, motivators, and coping options: 'distrust towards the employer', 'concurrent demands and challenges', 'professional ambiguity, 'a wish for collaboration', and 'efforts to gain control'. A common feature was duality and ambiguity in nurses' descriptions of the phenomena studied, meaning that identified themes had underlying sub-themes with both negative and positive dimensions. The concurrence of 'ever-growing job demands' and 'work going unrewarded' contributed to a feeling of being taken advantage of by the employer. The 'waste of human resources' and 'competence drain' that followed redundancies provoked anger. Unfulfilled collaboration with doctors was a major stress producer, which related to both the downsized work organization, and the complex 'deference-dominance' doctor-nurse relationship. The well-being of nurses depends on being an equal/parallel health professional in a comprehensive team that shares knowledge and improves collaborative care of patients. A consciously formulated nursing philosophy emerged as a

  13. Semantic ambiguity effects on traditional Chinese character naming: A corpus-based approach.

    Science.gov (United States)

    Chang, Ya-Ning; Lee, Chia-Ying

    2017-11-09

    Words are considered semantically ambiguous if they have more than one meaning and can be used in multiple contexts. A number of recent studies have provided objective ambiguity measures by using a corpus-based approach and have demonstrated ambiguity advantages in both naming and lexical decision tasks. Although the predictive power of objective ambiguity measures has been examined in several alphabetic language systems, the effects in logographic languages remain unclear. Moreover, most ambiguity measures do not explicitly address how the various contexts associated with a given word relate to each other. To explore these issues, we computed the contextual diversity (Adelman, Brown, & Quesada, Psychological Science, 17; 814-823, 2006) and semantic ambiguity (Hoffman, Lambon Ralph, & Rogers, Behavior Research Methods, 45; 718-730, 2013) of traditional Chinese single-character words based on the Academia Sinica Balanced Corpus, where contextual diversity was used to evaluate the present semantic space. We then derived a novel ambiguity measure, namely semantic variability, by computing the distance properties of the distinct clusters grouped by the contexts that contained a given word. We demonstrated that semantic variability was superior to semantic diversity in accounting for the variance in naming response times, suggesting that considering the substructure of the various contexts associated with a given word can provide a relatively fine scale of ambiguity information for a word. All of the context and ambiguity measures for 2,418 Chinese single-character words are provided as supplementary materials.

  14. Ambiguities of the phase analysis of the proton-proton scattering amplitude

    International Nuclear Information System (INIS)

    Grebenyuk, O.G.; Shklyarevskij, G.M.

    1980-01-01

    Ambiguities of the phase analysis of the proton-proton scattering amplitude are analysed. It is shown that for five measurements of polarization parameters sets there are ambiguities similar to the Gersten ambiguities in the phase analysis of πN scattering. A problem on additional experiments needed to eliminate these ambiguities is investigated. It is shown that for this purpose it suffices to measure three total cross sections with polarized and nonpolarized protons, thus determining the imaginary parts of amplitudes at THETA=0 and polarization parameters

  15. Lexical ambiguity resolution during sentence processing in Parkinson's disease: An event-related potential study.

    Directory of Open Access Journals (Sweden)

    Anthony J Angwin

    Full Text Available Event-related potentials (ERPs were recorded to investigate lexical ambiguity resolution during sentence processing in 16 people with Parkinson's disease (PD and 16 healthy controls. Sentences were presented word-by-word on computer screen, and participants were required to decide if a subsequent target word was related to the meaning of the sentence. The task consisted of related, unrelated and ambiguous trials. For the ambiguous trials, the sentence ended with an ambiguous word and the target was related to one of the meanings of that word, but not the one captured by the sentence context (e.g., 'He dug with the spade', Target 'ACE'. Both groups demonstrated slower reaction times and lower accuracy for the ambiguous condition relative to the unrelated condition, however accuracy was impacted by the ambiguous condition to a larger extent in the PD group. These results suggested that PD patients experience increased difficulties with contextual ambiguity resolution. The ERP results did not reflect increased ambiguity resolution difficulties in PD, as a similar N400 effect was evident for the unrelated and ambiguous condition in both groups. However, the magnitude of the N400 for these conditions was correlated with a measure of inhibition in the PD group, but not the control group. The ERP results suggest that semantic processing may be more compromised in PD patients with increased response inhibition deficits.

  16. The comprehension of ambiguous idioms in aphasic patients.

    Science.gov (United States)

    Cacciari, Cristina; Reati, Fabiola; Colombo, Maria Rosa; Padovani, Roberto; Rizzo, Silvia; Papagno, Costanza

    2006-01-01

    The ability to understand ambiguous idioms was assessed in 15 aphasic patients with preserved comprehension at a single word level. A string-to-word matching task was used. Patients were requested to choose one among four alternatives: a word associated with the figurative meaning of the idiom string; a word semantically associate with the last constituent of the idiom string; and two unrelated words. The results showed that patients' performance was impaired with respect to a group of matched controls, with patients showing a frontal and/or temporal lesion being the most impaired. A significant number of semantically associate errors were produced, suggesting an impairment of inhibition mechanisms and/or of recognition/activation of the idiomatic meaning.

  17. L’EXEMPLE AMBIGU OU LA PHRONESIS DU PHRONIMOS

    Directory of Open Access Journals (Sweden)

    Loïc NICOLAS

    2011-05-01

    Full Text Available The present contribution studies the concept and the theory of example starting from an analysis of the phronèsis – the intelligence of and in the action. We show that we cannot think the phronèsis without examples, i.e. without incarnating it into the one who puts it in practice. We also prove that – as content of the moral education – the phronimos, key figure of right judgment and eu zèn, appears of an undeniable ambiguity. This reflexion on the phronèsis of the phronimos gives the opportunity to raise several crucial questions on the role of the experiment, the usage of the practical judgment and the acquisition of freedom.

  18. Ambiguous genitalia, gender-identity problems, and sex reassignment.

    Science.gov (United States)

    Dittmann, R W

    1998-01-01

    This article discusses general issues with regard to gender-identity problems, sex reassignment, and clinical management in patients with ambiguous genitalia, based on a detailed case history of a patient with penile agenesis who has been followed more than 20 years. After initial uncertainty, the patient began to grow up as a boy, lived from the fourth year of life as a girl and young woman, and lived from late puberty on as a man. Over his lifetime he experienced extensive corrective surgery plus hormonal substitution therapy. Pre- and perinatal hormonal conditions, phenomenology of the genitalia, sex of rearing, timing of sex reassignment and corrective surgery, for example, appear to be important components for the development of gender-role behavior, gender identity, and sexual orientation of intersex patients. Findings and retrospective considerations for this patient suggest the need for careful differential activities in diagnostic workup, approaches to sex assignment and possible reassignment, and the clinical management of patients and families.

  19. Symmetry relations and ambiguities in a free-quark model

    International Nuclear Information System (INIS)

    Battistel, O.A.; Nemes, M.C.; Battistel, O.L.

    1998-01-01

    We present a systematic study of one, two and three point functions of vector axial-vector scalar and pseudoscalar densities constructed in a free-quark model in a point of view of a alternative strategy to manipulate and calculate divergent amplitudes. The divergent content of the amplitudes in this technique are left in the form of (external momenta independent) 4-D integrals. Ambiguities and Symmetry Violations in all cases are shown to be associated to terms which involved relations between divergent integrals of the same degree of divergence. We conclude then that it's possible to avoid all these problems. For this purpose a set of conditions must be fulfilled the same ones we need for preserving gauge symmetry in QED. The implications of our studies to others theories and models are also discussed. (author)

  20. Sensorimotor Adaptations Following Exposure to Ambiguous Inertial Motion Cues

    Science.gov (United States)

    Wood, S. J.; Harm, D. L.; Reschke, M. F.; Rupert, A. H.; Clement, G. R.

    2009-01-01

    The central nervous system must resolve the ambiguity of inertial motion sensory cues in order to derive accurate spatial orientation awareness. We hypothesize that multi-sensory integration will be adaptively optimized in altered gravity environments based on the dynamics of other sensory information available, with greater changes in otolith-mediated responses in the mid-frequency range where there is a crossover of tilt and translation responses. The primary goals of this ground-based research investigation are to explore physiological mechanisms and operational implications of tilt-translation disturbances during and following re-entry, and to evaluate a tactile prosthesis as a countermeasure for improving control of whole-body orientation.

  1. In Praise of Ambiguity: Musical Subtlety and Merleau-Ponty

    Directory of Open Access Journals (Sweden)

    Tiger C. Roholt

    2013-01-01

    Full Text Available When a jazz, rock, or hip-hop drummer strikes certain notes in each measure slightly late, instead of hearing the degree to which those notes are late, we typically hear the effects of those variations; namely, a groove, the "feel" of a rhythm. Slight variations of pitch function similarly. In this essay, I argue that certain analytic theorists go astray due to their preoccupation with the variations themselves. By invoking Maurice Merleau-Ponty's insights into subtle visual perceptions, and his notion of perceptual indeterminacy, I avoid an account of musical subtlety suggested by Daniel Dennett that is too coarse-grained, as well as the bleak conclusion that certain musical subtleties are ineffable, Diana Raffman's view. I conclude that elements of music that are perceived ambiguously can perform a positive function in such aesthetic experiences: they can mediate or foster emergent qualities; moreover, they must be perceived in this way to do so.

  2. Categorification and higher representation theory

    CERN Document Server

    Beliakova, Anna

    2017-01-01

    The emergent mathematical philosophy of categorification is reshaping our view of modern mathematics by uncovering a hidden layer of structure in mathematics, revealing richer and more robust structures capable of describing more complex phenomena. Categorified representation theory, or higher representation theory, aims to understand a new level of structure present in representation theory. Rather than studying actions of algebras on vector spaces where algebra elements act by linear endomorphisms of the vector space, higher representation theory describes the structure present when algebras act on categories, with algebra elements acting by functors. The new level of structure in higher representation theory arises by studying the natural transformations between functors. This enhanced perspective brings into play a powerful new set of tools that deepens our understanding of traditional representation theory. This volume exhibits some of the current trends in higher representation theory and the diverse te...

  3. Managing ambiguity in business. A holistic and innovative approach

    Directory of Open Access Journals (Sweden)

    Pop Oana

    2017-07-01

    Full Text Available This article will look at the hurdles of dealing with ambiguity and the wicked problems that organizations are struggling with, by providing key insights from a one year team coaching program that the author had the opportunity to deliver in a Romanian entrepreneurial organization. Based on the actual methods used and highlighting the findings and impact of the program, we will reflect on how ambiguity manifests in organizational settings and how wicked problems can be defined. The methods employed are within the range of complexity science and are holistic approaches to systemic interventions within organizations that combine soft systems methodology, paradoxical theory of change, complex responsive processes approach with important concepts from systems thinking such as archetypes, feedback loops and modeling. One of the key objectives of the article is to reunite different academic approaches and link them to a case study as a way of adding value to these approaches and to reiterate that research needs, to find its rightful place in the practitioners’ toolkit and have a more meaningful and direct impact on the real struggles that business is faced with. The author’s expertize in systemic interventions is based on extensive practitioner experience, having been trained and certified as a systemic coach and facilitator, and therefore draws upon the work of other skilled practitioners that support companies in finding successful ways to address complexity. Although the article can be easily put in the complexity science and systems thinking area of academic interest, the research questions and insights are intended to serve the learning and the evolution of organizations.

  4. Neural Computation of Surface Border Ownership and Relative Surface Depth from Ambiguous Contrast Inputs

    Science.gov (United States)

    Dresp-Langley, Birgitta; Grossberg, Stephen

    2016-01-01

    The segregation of image parts into foreground and background is an important aspect of the neural computation of 3D scene perception. To achieve such segregation, the brain needs information about border ownership; that is, the belongingness of a contour to a specific surface represented in the image. This article presents psychophysical data derived from 3D percepts of figure and ground that were generated by presenting 2D images composed of spatially disjoint shapes that pointed inward or outward relative to the continuous boundaries that they induced along their collinear edges. The shapes in some images had the same contrast (black or white) with respect to the background gray. Other images included opposite contrasts along each induced continuous boundary. Psychophysical results demonstrate conditions under which figure-ground judgment probabilities in response to these ambiguous displays are determined by the orientation of contrasts only, not by their relative contrasts, despite the fact that many border ownership cells in cortical area V2 respond to a preferred relative contrast. Studies are also reviewed in which both polarity-specific and polarity-invariant properties obtain. The FACADE and 3D LAMINART models are used to explain these data. PMID:27516746

  5. Neural Computation of Surface Border Ownership and Relative Surface Depth from Ambiguous Contrast Inputs.

    Science.gov (United States)

    Dresp-Langley, Birgitta; Grossberg, Stephen

    2016-01-01

    The segregation of image parts into foreground and background is an important aspect of the neural computation of 3D scene perception. To achieve such segregation, the brain needs information about border ownership; that is, the belongingness of a contour to a specific surface represented in the image. This article presents psychophysical data derived from 3D percepts of figure and ground that were generated by presenting 2D images composed of spatially disjoint shapes that pointed inward or outward relative to the continuous boundaries that they induced along their collinear edges. The shapes in some images had the same contrast (black or white) with respect to the background gray. Other images included opposite contrasts along each induced continuous boundary. Psychophysical results demonstrate conditions under which figure-ground judgment probabilities in response to these ambiguous displays are determined by the orientation of contrasts only, not by their relative contrasts, despite the fact that many border ownership cells in cortical area V2 respond to a preferred relative contrast. Studies are also reviewed in which both polarity-specific and polarity-invariant properties obtain. The FACADE and 3D LAMINART models are used to explain these data.

  6. Neural computation of surface border ownership and relative surface depth from ambiguous contrast inputs

    Directory of Open Access Journals (Sweden)

    Birgitta Dresp-Langley

    2016-07-01

    Full Text Available The segregation of image parts into foreground and background is an important aspect of the neural computation of 3D scene perception. To achieve such segregation, the brain needs information about border ownership; that is, the belongingness of a contour to a specific surface represented in the image. This article presents psychophysical data derived from 3D percepts of figure and ground that were generated by presenting 2D images composed of spatially disjoint shapes that pointed inward or outward relative to the continuous boundaries that they induced along their collinear edges. The shapes in some images had the same contrast (black or white with respect to the background gray. Other images included opposite contrasts along each induced continuous boundary. Results demonstrate conditions under which figure-ground judgment probabilities in response to these ambiguous displays are determined by the orientation of contrasts only, not by their relative contrasts, despite the fact that many border ownership cells in cortical area V2 respond to a preferred relative contrast. Studies are also reviewed in which both polarity-specific and polarity-invariant properties obtain. The FACADE and 3D LAMINART models are used to explain these data.

  7. CP trajectory diagram--a tool for a pictorial representation of CP and matter effects in neutrino oscillations

    International Nuclear Information System (INIS)

    Minakata, Hisakazu; Nunokawa, Hiroshi

    2003-01-01

    We introduce a 'CP trajectory diagram in bi-probability space' as a powerful tool for a pictorial representation of the genuine CP and the matter effects in neutrino oscillations. The existence of correlated ambiguity in the determination of CP-violating phase δ and the sign of Δm 13 2 is uncovered. The principles of tuning the beam energy for a given baseline distance are proposed to resolve the ambiguity and to maximize the CP-odd effect. We finally point out, quite contrary to what is usually believed, that the ambiguity may be resolved with ∼50% chance in the super-JHF experiment despite its relatively short baseline of 300 km

  8. The dark side of ambiguous discrimination: how state self-esteem moderates emotional and behavioural responses to ambiguous and unambiguous discrimination.

    Science.gov (United States)

    Cihangir, Sezgin; Barreto, Manuela; Ellemers, Naomi

    2010-03-01

    Two experiments examine how experimentally induced differences in state self-esteem moderate emotional and behavioural responses to ambiguous and unambiguous discrimination. Study 1 (N=108) showed that participants who were exposed to ambiguous discrimination report more negative self-directed emotions when they have low compared to high self-esteem. These differences did not emerge when participants were exposed to unambiguous discrimination. Study 2 (N=118) additionally revealed that self-esteem moderated the effect of ambiguous discrimination on self-concern, task performance, and self-stereotyping. Results show that ambiguous discrimination caused participants with low self-esteem to report more negative self-directed emotions, more self-concern, an inferior task performance, and more self-stereotyping, compared to participants in the high self-esteem condition. Emotional and behavioural responses to unambiguous discrimination did not depend on the induced level of self-esteem in these studies.

  9. Representation of the Divine

    DEFF Research Database (Denmark)

    Loddegaard, Anne

    2012-01-01

    out of place in a novel belonging to the serious combat literature of the Catholic Revival, and the direct representation of the supernatural is also surprising because previous Catholic Revival novelists, such as Léon Bloy and Karl-Joris Huysmans, maintain a realistic, non-magical world and deal...... Satan episode in Under Satan’s Sun is neither a break with the seriousness nor with the realism of the Catholic novel. On the basis of Tvetan Todorov’s definition of the traditional fantastic tale, the analysis shows that only the beginning of the fantastic episode follows Todorov’s definition...

  10. Representation of the Divine

    DEFF Research Database (Denmark)

    Loddegaard, Anne

    2009-01-01

    out of place in a novel belonging to the serious combat literature of the Catholic Revival, and the direct representation of the supernatural is also surprising because previous Catholic Revival novelists, such as Léon Bloy and Karl-Joris Huysmans, maintain a realistic, non-magical world and deal...... Satan episode in Under Satan’s Sun is neither a break with the seriousness nor with the realism of the Catholic novel. On the basis of Tvetan Todorov’s definition of the traditional fantastic tale, the analysis shows that only the beginning of the fantastic episode follows Todorov’s definition...

  11. Representations of commonsense knowledge

    CERN Document Server

    Davis, Ernest

    1990-01-01

    Representations of Commonsense Knowledge provides a rich language for expressing commonsense knowledge and inference techniques for carrying out commonsense knowledge. This book provides a survey of the research on commonsense knowledge.Organized into 10 chapters, this book begins with an overview of the basic ideas on artificial intelligence commonsense reasoning. This text then examines the structure of logic, which is roughly analogous to that of a programming language. Other chapters describe how rules of universal validity can be applied to facts known with absolute certainty to deduce ot

  12. Between Representation and Eternity

    DEFF Research Database (Denmark)

    Atzbach, Rainer

    2016-01-01

    This paper seeks to explore how prayer and praying practice are reflected in archaeological sources. Apart from objects directly involved in the personal act of praying, such as rosaries and praying books, churches and religious foundations played a major role in the medieval system of intercession....... At death, an indi- vidual’s corpse and burial primarily reflect the social act of representation during the funeral. The position of the arms, which have incorrectly been used as a chronological tool in Scandinavia, may indicate an evolution from a more collective act of prayer up to the eleventh century...

  13. Neural responses to ambiguity involve domain-general and domain-specific emotion processing systems.

    Science.gov (United States)

    Neta, Maital; Kelley, William M; Whalen, Paul J

    2013-04-01

    Extant research has examined the process of decision making under uncertainty, specifically in situations of ambiguity. However, much of this work has been conducted in the context of semantic and low-level visual processing. An open question is whether ambiguity in social signals (e.g., emotional facial expressions) is processed similarly or whether a unique set of processors come on-line to resolve ambiguity in a social context. Our work has examined ambiguity using surprised facial expressions, as they have predicted both positive and negative outcomes in the past. Specifically, whereas some people tended to interpret surprise as negatively valenced, others tended toward a more positive interpretation. Here, we examined neural responses to social ambiguity using faces (surprise) and nonface emotional scenes (International Affective Picture System). Moreover, we examined whether these effects are specific to ambiguity resolution (i.e., judgments about the ambiguity) or whether similar effects would be demonstrated for incidental judgments (e.g., nonvalence judgments about ambiguously valenced stimuli). We found that a distinct task control (i.e., cingulo-opercular) network was more active when resolving ambiguity. We also found that activity in the ventral amygdala was greater to faces and scenes that were rated explicitly along the dimension of valence, consistent with findings that the ventral amygdala tracks valence. Taken together, there is a complex neural architecture that supports decision making in the presence of ambiguity: (a) a core set of cortical structures engaged for explicit ambiguity processing across stimulus boundaries and (b) other dedicated circuits for biologically relevant learning situations involving faces.

  14. Image understanding systems based on the unifying representation of perceptual and conceptual information and the solution of mid-level and high-level vision problems

    Science.gov (United States)

    Kuvychko, Igor

    2001-10-01

    Vision is a part of a larger information system that converts visual information into knowledge structures. These structures drive vision process, resolving ambiguity and uncertainty via feedback, and provide image understanding, that is an interpretation of visual information in terms of such knowledge models. A computer vision system based on such principles requires unifying representation of perceptual and conceptual information. Computer simulation models are built on the basis of graphs/networks. The ability of human brain to emulate similar graph/networks models is found. That means a very important shift of paradigm in our knowledge about brain from neural networks to the cortical software. Starting from the primary visual areas, brain analyzes an image as a graph-type spatial structure. Primary areas provide active fusion of image features on a spatial grid-like structure, where nodes are cortical columns. The spatial combination of different neighbor features cannot be described as a statistical/integral characteristic of the analyzed region, but uniquely characterizes such region itself. Spatial logic and topology naturally present in such structures. Mid-level vision processes like clustering, perceptual grouping, multilevel hierarchical compression, separation of figure from ground, etc. are special kinds of graph/network transformations. They convert low-level image structure into the set of more abstract ones, which represent objects and visual scene, making them easy for analysis by higher-level knowledge structures. Higher-level vision phenomena like shape from shading, occlusion, etc. are results of such analysis. Such approach gives opportunity not only to explain frequently unexplainable results of the cognitive science, but also to create intelligent computer vision systems that simulate perceptional processes in both what and where visual pathways. Such systems can open new horizons for robotic and computer vision industries.

  15. Social Representations of Intelligence

    Directory of Open Access Journals (Sweden)

    Elena Zubieta

    2016-02-01

    Full Text Available The article stresses the relationship between Explicit and Implicit theories of Intelligence. Following the line of common sense epistemology and the theory of Social Representations, a study was carried out in order to analyze naive’s explanations about Intelligence Definitions. Based on Mugny & Carugati (1989 research, a self-administered questionnaire was designed and filled in by 286 subjects. Results are congruent with the main hyphotesis postulated: A general overlap between explicit and implicit theories showed up. According to the results Intelligence appears as both, a social attribute related to social adaptation and as a concept defined in relation with contextual variables similar to expert’s current discourses. Nevertheless, conceptions based on “gifted ideology” still are present stressing the main axes of Intelligence debate: biological and sociological determinism. In the same sense, unfamiliarity and social identity are reaffirmed as organizing principles of social representation. The distance with the object -measured as the belief in intelligence differences as a solve/non solve problem- and the level of implication with the topic -teachers/no teachers- appear as discriminating elements at the moment of supporting specific dimensions. 

  16. Midwestern Millennial University Students' Tolerance for Ambiguity in a Period of Complex World Conflicts

    Science.gov (United States)

    Mahdi, Ghada S.

    2012-01-01

    Though age and gender do not affect students' knowledge of global issues and associated ambiguity, the academic major of undergraduates did. Students' combined perceptions on knowledge of these issues and their associated ambiguities varied among the four academic groups of majors. Unlike teacher education majors and in combined other majors…

  17. Sadder but wiser : the effects of emotional states on ambiguity attitudes

    NARCIS (Netherlands)

    Baillon, A.; Koelinger, P.; Treffers, T.

    “Many important decisions are made without precise information about the probabilities of the outcomes. In such situations, individual ambiguity attitudes influence decision making. The present study identifies emotions as a transient cause of ambiguity attitudes. We conducted two random-assignment,

  18. Aggregating imprecise or conflicting beliefs: An experimental investigation using modern ambiguity theories

    NARCIS (Netherlands)

    A. Baillon (Aurélien); L. Cabantous (Laure); P.P. Wakker (Peter)

    2012-01-01

    textabstractTwo experiments show that violations of expected utility due to ambiguity, found in general decision experiments, also affect belief aggregation. Hence we use modern ambiguity theories to analyze belief aggregation, thus obtaining more refined and empirically more valid results than

  19. In the Face of Uncertainty: A Twin Study of Ambiguous Information, Anxiety and Depression in Children

    Science.gov (United States)

    Eley, Thalia C.; Gregory, Alice M.; Lau, Jennifer Y. F.; McGuffin, Peter; Napolitano, Maria; Rijsdijk, Fruhling V.; Clark, David M.

    2008-01-01

    Anxiety and depression share genetic influences, and have been associated with similar cognitive biases. Psychological theories of anxiety and depression highlight threat interpretations of ambiguity. Little is known about whether genes influence cognitive style, or its links to symptoms. We assessed ambiguous word and scenario interpretations,…

  20. On the Impact of L2 Speech Rhythm on Syntactic Ambiguity Resolution

    Science.gov (United States)

    Roncaglia-Denissen, M. Paula; Schmidt-Kassow, Maren; Heine, Angela; Kotz, Sonja A.

    2015-01-01

    In an event-related potential (ERP) study we investigated the role of age of acquisition (AoA) on the use of second language rhythmic properties during syntactic ambiguity resolution. Syntactically ambiguous sentences embedded in rhythmically regular and irregular contexts were presented to Turkish early and late second language (L2) learners of…