Science.gov

Sample records for give ambiguous results

  1. Ambiguity resolution strategies using the results of the International GPS Geodynamics Service (IGS)

    NASA Astrophysics Data System (ADS)

    Mervart, Leoš; Beutler, Gerhard; Rothacher, Markus; Wild, Urs

    1994-03-01

    Resolving the initial phase ambiguities of GPS carrier phase observations was always considered an important aspect of GPS processing techniques. Resolution of the so-called wide-lane ambiguities using a special linear combination of the L 1 and L 2 carrier and code observations has become standard. New aspects have to be considered today: (1) Soon AS, the so-called Anti-Spoofing, will be turned on for all Block II spacecrafts. This means that precise code observations will be no longer available, which in turn means that the mentioned approach to resolve the wide-lane ambiguities will fail. (2) Most encouraging is the establishment of the new International GPS Geodynamics Service (IGS), from where high quality orbits, earth rotation parameters, and eventually also ionospheric models will be available. We are reviewing the ambiguity resolution problem under these new aspects: We look for methods to resolve the initial phase ambiguities without using code observations but using high quality orbits and ionospheric models from IGS, and we study the resolution of the ”narrow-lane ambiguities” (after wide-lane ambiguity resolution) using IGS orbits.

  2. Image Ambiguity and Fluency

    PubMed Central

    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. Lost in Translation: Ambiguity in Nerve Sheath Tumor Nomenclature and Its Resultant Treatment Effect

    PubMed Central

    Bernthal, Nicholas M.; Jones, Kevin B.; Monument, Michael J.; Liu, Ting; Viskochil, David; Randall, R. Lor

    2013-01-01

    There is much ambiguity surrounding the diagnosis of nerve sheath tumors, including atypical neurofibroma and low-grade MPNST, and yet, the distinction between these entities designates either benign or malignant behavior and thus carries presumed profound prognostic importance that often guides treatment. This study reviews the diagnostic criteria used to designate atypical neurofibroma from low-grade MPNSTs and reviews existing literature the natural history of each of these tumors to see if the distinction is, in fact, of importance. PMID:24216989

  4. Lost in translation: ambiguity in nerve sheath tumor nomenclature and its resultant treatment effect.

    PubMed

    Bernthal, Nicholas M; Jones, Kevin B; Monument, Michael J; Liu, Ting; Viskochil, David; Randall, R Lor

    2013-05-08

    There is much ambiguity surrounding the diagnosis of nerve sheath tumors, including atypical neurofibroma and low-grade MPNST, and yet, the distinction between these entities designates either benign or malignant behavior and thus carries presumed profound prognostic importance that often guides treatment. This study reviews the diagnostic criteria used to designate atypical neurofibroma from low-grade MPNSTs and reviews existing literature the natural history of each of these tumors to see if the distinction is, in fact, of importance.

  5. Reduced ambiguity calibration for LOFAR

    NASA Astrophysics Data System (ADS)

    Yatawatta, Sarod

    2012-07-01

    Interferometric calibration always yields non unique solutions. It is therefore essential to remove these ambiguities before the solutions could be used in any further modeling of the sky, the instrument or propagation effects such as the ionosphere. We present a method for LOFAR calibration which does not yield a unitary ambiguity, especially under ionospheric distortions. We also present exact ambiguities we get in our solutions, in closed form. Casting this as an optimization problem, we also present conditions for this approach to work. The proposed method enables us to use the solutions obtained via calibration for further modeling of instrumental and propagation effects. We provide extensive simulation results on the performance of our method. Moreover, we also give cases where due to degeneracy, this method fails to perform as expected and in such cases, we suggest exploiting diversity in time, space and frequency.

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

    PubMed

    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. PMID:25698984

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

    PubMed Central

    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

    2015-01-01

    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. PMID:25698984

  8. Charitable Giving for HIV and AIDS: Results from a Canadian National Survey

    PubMed Central

    Allman, Dan; Calzavara, Liviana; Worthington, Catherine; Tyndall, Mark; Adrien, Alix; Walters, Melissa; White, Samantha; Jones, Marcella K.

    2014-01-01

    Background For the first time, a national survey of adults in Canada posed questions on charitable giving for HIV and AIDS. The objective of this analysis was to explore the behaviour and attitudes of this population in terms of charitable giving. Methods In 2011, individuals in Canada 16 years of age or older were recruited for a survey from an online panel supplemented by random digit dial telephone interviewing. The margin of error was +/−2.1 percentage points (95%). Chi-square tests were used to detect bivariate associations. A multivariate logistic regression model was fit to compare those who had donated to HIV and AIDS in the past 12 months with those who had donated to other disease or illness charities. Results 2,139 participated. 82.5% had donated to a charitable cause in the past 12 months. 22.2% had ever donated to HIV and AIDS, with 7.8% doing so in the past 12 months. Individuals who had donated to HIV and AIDS versus other disease or illness charities tended to be younger (p<0.05), single (p<0.005), more highly educated (p<0.001) and to self-identify as a member of a sexual minority group (p<0.001). Multivariate analysis revealed individuals who self-identified as a member of a sexual minority group were significantly much more likely to have donated to HIV and AIDS than to other disease or illness charities in the past 12 months (OR, 7.73; p<0.001; CI 4.32–13.88). Discussion Despite a generally philanthropic orientation, relatively few respondents had ever been involved in charitable giving for HIV and AIDS. Those who had could be understood relationally as individuals at closer social proximity to HIV and AIDS such as members of sexual minority groups. PMID:25153827

  9. Neural response to modulating the probability that actions of self or other result in auditory tones: A parametric fMRI study into causal ambiguity.

    PubMed

    de Bézenac, Christophe E; Sluming, Vanessa; Gouws, André; Corcoran, Rhiannon

    2016-09-01

    In normal circumstances we can easily distinguish between changes to the external world brought about by our own actions from those with external causes. However, in certain contexts our sense of ownership and agency over acts is not so clear. Neuroimaging studies have implicated a number of regions in the sense of agency, some of which have been shown to vary continuously with action-outcome discordance. However, little is known about dynamic, ambiguous contexts characterised by a lack of information for self-other differentiation, yet such ambiguous states are important in relation to symptoms and levels of consciousness that characterise certain mental health conditions. With a block-design fMRI paradigm, we investigated neural responses to changes in the probability that a participant's irregular finger taps over 12s would result in auditory tones as opposed to tones generated by 'another's finger taps'. The main findings were that misattribution increased in ambiguous conditions where the probability of a tone belonging to self and other was equal. Task-sensitive brain regions, previously identified in self-agency, motor cognition, and ambiguity processing, showed a quadratic response to our self-to-other manipulation, with particular sensitivity to self-control. Task performance (low error and bias) was related to attenuated response in ambiguous conditions while increased response in regions associated with the default mode network was associated with greater overall error and bias towards other. These findings suggest that causal ambiguity as it occurs over time is a prominent feature in sense of agency, one that may eventually contribute to a more comprehensive understanding of positive symptoms of psychosis.

  10. Neural response to modulating the probability that actions of self or other result in auditory tones: A parametric fMRI study into causal ambiguity.

    PubMed

    de Bézenac, Christophe E; Sluming, Vanessa; Gouws, André; Corcoran, Rhiannon

    2016-09-01

    In normal circumstances we can easily distinguish between changes to the external world brought about by our own actions from those with external causes. However, in certain contexts our sense of ownership and agency over acts is not so clear. Neuroimaging studies have implicated a number of regions in the sense of agency, some of which have been shown to vary continuously with action-outcome discordance. However, little is known about dynamic, ambiguous contexts characterised by a lack of information for self-other differentiation, yet such ambiguous states are important in relation to symptoms and levels of consciousness that characterise certain mental health conditions. With a block-design fMRI paradigm, we investigated neural responses to changes in the probability that a participant's irregular finger taps over 12s would result in auditory tones as opposed to tones generated by 'another's finger taps'. The main findings were that misattribution increased in ambiguous conditions where the probability of a tone belonging to self and other was equal. Task-sensitive brain regions, previously identified in self-agency, motor cognition, and ambiguity processing, showed a quadratic response to our self-to-other manipulation, with particular sensitivity to self-control. Task performance (low error and bias) was related to attenuated response in ambiguous conditions while increased response in regions associated with the default mode network was associated with greater overall error and bias towards other. These findings suggest that causal ambiguity as it occurs over time is a prominent feature in sense of agency, one that may eventually contribute to a more comprehensive understanding of positive symptoms of psychosis. PMID:27381929

  11. The Ambiguity in Immunology

    PubMed Central

    Barnaba, Vincenzo; Paroli, Marino; Piconese, Silvia

    2012-01-01

    In the present article, we discuss the various ambiguous aspects of the immune system that render this complex biological network so highly flexible and able to defend the host from different external invaders. This ambiguity stems mainly from the property of the immune system to be both protective and harmful. Immunity cannot be fully protective without producing a certain degree of damage (immunopathology) to the host. The balance between protection and tissue damage is, therefore, critical for the establishment of immune homeostasis and protection. In this review, we will consider as ambiguous, various immunological tactics including: (a) the opposing functions driving immune responses, immune-regulation, and contra-regulation, as well as (b) the phenomenon of chronic immune activation as a result of a continuous cross-presentation of apoptotic T cells by dendritic cells. All these plans participate principally to maintain a state of chronic low-level inflammation during persisting infections, and ultimately to favor the species survival. PMID:22566903

  12. On Syntactic Ambiguity.

    ERIC Educational Resources Information Center

    van Oirsouw, Robert R.

    The source of syntactic ambiguity and facts concerning the resolution of such ambiguity are discussed in this paper. The attitude of qenerative linguists towards ambiguity is examined, and a working distinction is drawn between vaqueness and ambiguity. The consequences of this distinction are then examined for syntactic ambiguity and an ordering…

  13. Quantum vs Classical Mechanics for a 'Simple' Dissociation Reaction. Should They Give the Same Results?

    NASA Astrophysics Data System (ADS)

    Holloway, Stephen

    1997-03-01

    When performing molecular dynamical simulations on light systems at low energies, there is always the risk of producing data that bear no similarity to experiment. Indeed, John Barker himself was particularly anxious about treating Ar scattering from surfaces using classical mechanics where it had been shown experimentally in his own lab that diffraction occurs. In such cases, the correct procedure is probably to play the trump card "... well of course, quantum effects will modify this so that....." and retire gracefully. For our particular interests, the tables are turned in that we are interested in gas-surface dynamical studies for highly quantized systems, but would be interested to know when it is possible to use classical mechanics in order that a greater dimensionality might be treated. For molecular dissociation and scattering, it has been oft quoted that the greater the number of degrees of freedom, the more appropriate is classical mechanics, primarily because of the mass averaging over the quantized dimensions. Is this true? We have been investigating the dissociation of hydrogen molecules at surfaces and in this talk I will present quantum results for dissociation and scattering, along with a novel method for their interpretation based upon adiabatic potential energy surfaces. Comparison with classical calculations will be made and conclusions drawn. a novel method for their interpretation based upon adiabatic potential energy surfaces

  14. Repeated vitrification/warming of human sperm gives better results than repeated slow programmable freezing

    PubMed Central

    Vutyavanich, Teraporn; Lattiwongsakorn, Worashorn; Piromlertamorn, Waraporn; Samchimchom, Sudarat

    2012-01-01

    In this study, we compared the effects of repeated freezing/thawing of human sperm by our in-house method of rapid freezing with slow programmable freezing. Sperm samples from 11 normozoospermic subjects were processed through density gradients and divided into three aliquots: non-frozen, rapid freezing and slow programmable freezing. Sperm in the rapid freezing group had better motility and viability than those in the slow freezing group (P<0.01) after the first, second and third cycles of freezing/thawing, but there was no difference in morphology. In the second experiment, rapid freezing was repeated three times in 20 subjects. The samples from each thawing cycle were evaluated for DNA fragmentation using the alkaline comet assay. DNA fragmentation began to increase considerably after the second cycle of freezing/thawing, but to a level that was not clinically important. In the third experiment, rapid freezing was done repeatedly in 10 subjects, until no motile sperm were observed after thawing. The median number of repeated freezing/thawing that yielded no motile sperm was seven (range: 5–8, mean: 6.8). In conclusion, we demonstrated that repeated freezing/thawing of processed semen using our rapid freezing method gave better results than standard slow programmable freezing. This method can help maximize the usage of precious cryopreserved sperm samples in assisted reproduction technology. PMID:23064685

  15. Fermionic entanglement ambiguity in noninertial frames

    SciTech Connect

    Montero, Miguel; Martin-Martinez, Eduardo

    2011-06-15

    We analyze an ambiguity in previous works on entanglement of fermionic fields in noninertial frames. This ambiguity, related to the anticommutation properties of field operators, leads to nonunique results when computing entanglement measures for the same state. We show that the ambiguity disappears when we introduce detectors, which are in any case necessary as a means to probe the field entanglement.

  16. Lexical ambiguity in sentence comprehension

    PubMed Central

    Mason, Robert A.; Just, Marcel Adam

    2009-01-01

    An event-related fMRI paradigm was used to investigate brain activity during the reading of sentences containing either a lexically ambiguous word or an unambiguous control word. Higher levels of activation occurred during the reading of sentences containing a lexical ambiguity. Furthermore, the activated cortical network differed, depending on: (1) whether the sentence contained a balanced (i.e., both meanings equally likely) or a biased (i.e., one meaning more likely than other meanings) ambiguous word; and, (2) the working memory capacity of the individual as assessed by reading span. The findings suggest that encountering a lexical ambiguity is dealt with by activating multiple meanings utilizing processes involving both hemispheres. When an early interpretation of a biased ambiguous word is later disambiguated to the subordinate meaning, the superior frontal cortex activates in response to the coherence break and the right inferior frontal gyrus and the insula activate, possibly to suppress the incorrect interpretation. Negative correlations between reading span scores and activation in the right hemisphere for both types of ambiguous words suggest that readers with lower spans are more likely to involve show right hemisphere involvement in the processing of the ambiguity. A positive correlation between reading span scores and insula activation appearing only for biased sentences disambiguated to the subordinate meaning indicates that individuals with higher spans were more likely to initially maintain both meanings and as a result had to suppress the unintended dominant meaning. PMID:17433891

  17. Ethical Ambiguity in Science.

    PubMed

    Johnson, David R; Ecklund, Elaine Howard

    2016-08-01

    Drawing on 171 in-depth interviews with physicists at universities in the United States and the UK, this study examines the narratives of 48 physicists to explain the concept of ethical ambiguity: the border where legitimate and illegitimate conduct is blurred. Researchers generally assume that scientists agree on what constitutes both egregious and more routine forms of misconduct in science. The results of this study show that scientists perceive many scenarios as ethically gray, rather than black and white. Three orientations to ethical ambiguity are considered-altruism, inconsequential outcomes, and preserving the status quo-that allow possibly questionable behavior to persist unchallenged. Each discursive strategy is rationalized as promoting the collective interest of science rather than addressing what is ethically correct or incorrect. The results of this study suggest that ethics training in science should focus not only on fabrication, falsification, and plagiarism and more routine forms of misconduct, but also on strategies for resolving ethically ambiguous scenarios where appropriate action may not be clear.

  18. Ambiguous games: evidence for strategic ambiguity aversion.

    PubMed

    Pulford, Briony D; Colman, Andrew M

    2007-08-01

    The problem of ambiguity in games is discussed, and a class of ambiguous games is identified. A total of 195 participants played strategic-form games of various sizes with unidentified co-players. In each case, they first chose between a known-risk game involving a co-player indifferent between strategies and an equivalent ambiguous game involving one of several co-player types, each with a different dominant strategy, and then they chose a strategy for the preferred game. Half the players knew that the ambiguous co-player types were equally likely, and half did not. Half expected the outcomes to be known immediately, and half expected a week's delay. Known-risk games were generally preferred, confirming a significant strategic ambiguity aversion effect. In the delay conditions, players who knew that the ambiguous co-player types were equally likely were significantly less ambiguity averse than those who did not. Decision confidence was significantly higher in 2 x 2 than in larger games.

  19. SAR ambiguous range suppression.

    SciTech Connect

    Doerry, Armin Walter

    2006-09-01

    Pulsed Radar systems suffer range ambiguities, that is, echoes from pulses transmitted at different times arrive at the receiver simultaneously. Conventional mitigation techniques are not always adequate. However, pulse modulation schemes exist that allow separation of ambiguous ranges in Doppler space, allowing easy filtering of problematic ambiguous ranges.

  20. On Ambiguity and Organizations

    ERIC Educational Resources Information Center

    Lerner, Allan W.

    1978-01-01

    Ambiguity in the structure of decision-makers relationships is considered for the strategic opportunities it offers calculating actors. Ambiguity is discussed in the context of reciprocity, authority, and jurisdictional facets of relationships. The value of ambiguity as a common theme linking rational actor and system level concepts is also…

  1. Vignettes of Ambiguity

    ERIC Educational Resources Information Center

    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…

  2. Processing Coordination Ambiguity

    ERIC Educational Resources Information Center

    Engelhardt, Paul E.; Ferreira, Fernanda

    2010-01-01

    We examined temporarily ambiguous coordination structures such as "put the butter in the bowl and the pan on the towel." Minimal Attachment predicts that the ambiguous noun phrase "the pan" will be interpreted as a noun-phrase coordination structure because it is syntactically simpler than clausal coordination. Constraint-based theories assume…

  3. Effective ambiguity checking in biosequence analysis

    PubMed Central

    Reeder, Janina; Steffen, Peter; Giegerich, Robert

    2005-01-01

    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. PMID:15967024

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

    PubMed Central

    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. PMID:26640434

  5. Integer aperture ambiguity resolution based on difference test

    NASA Astrophysics Data System (ADS)

    Zhang, Jingyu; Wu, Meiping; Li, Tao; Zhang, Kaidong

    2015-07-01

    Carrier-phase integer ambiguity resolution (IAR) is the key to highly precise, fast positioning and attitude determination with Global Navigation Satellite System (GNSS). It can be seen as the process of estimating the unknown cycle ambiguities of the carrier-phase observations as integers. Once the ambiguities are fixed, carrier phase data will act as the very precise range data. Integer aperture (IA) ambiguity resolution is the combination of acceptance testing and integer ambiguity resolution, which can realize better quality control of IAR. Difference test (DT) is one of the most popular acceptance tests. This contribution will give a detailed analysis about the following properties of IA ambiguity resolution based on DT: 1. The sharpest and loose upper bounds of DT are derived from the perspective of geometry. These bounds are very simple and easy to be computed, which give the range for the critical values of DT.

  6. Management of ambiguities in magnetostratigraphic correlation

    NASA Astrophysics Data System (ADS)

    Lallier, Florent; Antoine, Christophe; Charreau, Julien; Caumon, Guillaume; Ruiu, Jeremy

    2013-06-01

    Magnetostratigraphy is a powerful tool to provide absolute dating of sediments enabling robust and detailed chronostratigraphic correlations. It is based on the correlation of a magnetic polarity column, observed and measured in a given sediment section, to a magnetic polarity reference scale where polarity changes are well dated via other independent methods. However, magnetostratigraphic correlations are loose as they are only constrained by binary magnetic chrons (i.e. normal or reversal) and their thickness, which are both defined from depth variations of the magnetic remanent directions. The thickness of a given magnetic polarity zone is a function of time and sediment accumulation rate, which may not be stationary, leading to ambiguities when performing the correlations. To address these ambiguities, a numerical method based on the Dynamic Time Warping algorithm is proposed. Magnetostratigraphic correlations are computed in order to minimise the local variation of the accumulation rate. The main advantage of the proposed method is to automatically provide a set of reasonably likely correlations. This set can then be scrutinised for further analysis and interpretation. However, the likelihood of a correlation should be handled carefully as it depends on the information content of the magnetostratigraphic section itself and remain ultimately valid by ancillary constraint. Nevertheless, the method gives consistent results on difficult synthetic cases that simulate abrupt variations of the sedimentation rate. Insights on true sections debated by previous authors are also given.

  7. Lexical ambiguity resolution

    SciTech Connect

    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.

  8. Ambiguity noise analysis of a SAR system

    NASA Astrophysics Data System (ADS)

    Tian, Haishan; Chang, Wenge; Li, Xiangyang

    2015-12-01

    The presence of range and azimuth (or Doppler) ambiguities in synthetic aperture radars (SARs) is well known. The ambiguity noise is related to the antenna pattern and the value of pulse repetition frequency (PRF). Because a new frequency modulated continuous wave (FMCW) SAR has the characters of low cost and small size, and the capacity of real-time signal processing, the antenna will likely vibrate or deform due to a lack of the stabilized platform. And the value of PRF cannot be much high because of the high computation burden for the real-time processing. The aim of this study is to access and improve the performance of a new FMCW SAR system based on the ambiguity noise. First, the quantitative analysis of the system's ambiguity noise level is performed; an antenna with low sidelobes is designed. The conclusion is that the range ambiguity noise is small; the azimuth ambiguity noise is somewhat increased, however, it is sufficiently small to have marginal influence on the image quality. Finally, the ambiguity noise level is measured using the imaging data from a Ku-band FMCW SAR. The results of this study show that the measured noise level coincides with the theoretical noise level.

  9. Some Structural Ambiguities.

    ERIC Educational Resources Information Center

    Stageberg, Norman C.

    1958-01-01

    The identification and study of 20 syntactical patterns responsible for much of the structural ambiguity found in literary composition can develop in students an audience awareness. When they realize that such constructions as "a dull boy's knife" and "the club will be open to members from Monday to Thursday" can be misinterpreted, they take more…

  10. Boundary Ambiguity in Stepfamilies

    ERIC Educational Resources Information Center

    Stewart, Susan D.

    2005-01-01

    Family boundary ambiguity refers to a lack of clarity as to who is in and who is out of the family system. Few studies have examined this concept in the stepfamily context, which is problematic because such definitional problems hinder our understanding of close relationships in stepfamilies. Based on a nationally representative sample of…

  11. Processing ambiguous verbs: evidence from eye movements.

    PubMed

    Pickering, M J; Frisson, S

    2001-03-01

    In 2 eye-tracking experiments, participants read verbs that had 2 (unrelated) meanings or 2 (related) senses in contexts that disambiguated before or after the verb, to the dominant or subordinate interpretation. A 3rd experiment used unambiguous verbs. The results indicated that the language processor used information about context in the early stages of resolving meaning ambiguities but only during integration for sense ambiguities. Effects of preference were delayed for both types of verbs. The results contrast with findings concerning the processing of nouns (e.g., K. Rayner & S. A. Duffy, 1986). For meaning ambiguities, the authors argue that delays in resolution allow both meanings to reach a high level of activation, thus reducing effects of frequency. For sense ambiguities, the authors argue that the processor does not access multiple senses but activates one underspecified meaning and uses context to home in on the appropriate sense.

  12. The Ambiguous Dying Syndrome

    ERIC Educational Resources Information Center

    Bern-Klug, Mercedes

    2004-01-01

    More than one-half of the 2.4 million deaths that will occur in the United States in 2004 will be immediately preceded by a time in which the likelihood of dying can best be described as "ambiguous." Many people die without ever being considered "dying" or "at the end of life." These people may miss out on the opportunity to close important…

  13. Facing ambiguous threats.

    PubMed

    Roberto, Michael A; Bohmer, Richard M J; Edmondson, Amy C

    2006-11-01

    On February 1, 2003, the world watched in horror as the Columbia space shuttle broke apart while reentering the earth's atmosphere, killing all seven astronauts. Some have argued that NASA's failure to respond with appropriate intensity to the so-called foam strike that led to the accident was evidence of irresponsible or incompetent management. The authors' research, however, suggests that NASA was exhibiting a natural, albeit unfortunate, pattern of behavior common in many organizations. The foam strike is a prime example of what the authors call an ambiguous threat-a signal that may or may not portend future harm. Ambiguous threats differ from threats with obvious causes-say, a fire in the building-for which the response is clear. They also differ from unmistakable threats that may lack straightforward response paths (such as the frightening oxygen-tank explosion aboard Apollo 13). However, when the warning sign is ambiguous and the threat's potential effect is unclear, managers may choose to ignore or discount the risk. Such an approach can be catastrophic. Firms that do a good job of dealing with ambiguous threats do not improvise during a crisis; rather, they apply a rigorous set of detection and response capabilities that they have developed and practiced beforehand. In this article, the authors outline how to put such capabilities in place long before a crisis strikes. First, companies need to hone their teamwork and rapid problem-solving skills through practice. Second, they must learn to recognize weak signals, amplify the threat, and encourage employees to ask disconcerting "what if" questions in a safe environment. Finally, they should explore possible responses to threats through quick, low-cost experimentation.

  14. Facing ambiguous threats.

    PubMed

    Roberto, Michael A; Bohmer, Richard M J; Edmondson, Amy C

    2006-11-01

    On February 1, 2003, the world watched in horror as the Columbia space shuttle broke apart while reentering the earth's atmosphere, killing all seven astronauts. Some have argued that NASA's failure to respond with appropriate intensity to the so-called foam strike that led to the accident was evidence of irresponsible or incompetent management. The authors' research, however, suggests that NASA was exhibiting a natural, albeit unfortunate, pattern of behavior common in many organizations. The foam strike is a prime example of what the authors call an ambiguous threat-a signal that may or may not portend future harm. Ambiguous threats differ from threats with obvious causes-say, a fire in the building-for which the response is clear. They also differ from unmistakable threats that may lack straightforward response paths (such as the frightening oxygen-tank explosion aboard Apollo 13). However, when the warning sign is ambiguous and the threat's potential effect is unclear, managers may choose to ignore or discount the risk. Such an approach can be catastrophic. Firms that do a good job of dealing with ambiguous threats do not improvise during a crisis; rather, they apply a rigorous set of detection and response capabilities that they have developed and practiced beforehand. In this article, the authors outline how to put such capabilities in place long before a crisis strikes. First, companies need to hone their teamwork and rapid problem-solving skills through practice. Second, they must learn to recognize weak signals, amplify the threat, and encourage employees to ask disconcerting "what if" questions in a safe environment. Finally, they should explore possible responses to threats through quick, low-cost experimentation. PMID:17131567

  15. REDUCING AMBIGUITY IN THE FUNCTIONAL ASSESSMENT OF PROBLEM BEHAVIOR

    PubMed Central

    Rooker, Griffin W.; DeLeon, Iser G.; Borrero, Carrie S. W.; Frank-Crawford, Michelle A.; Roscoe, Eileen M.

    2015-01-01

    Severe problem behavior (e.g., self-injury and aggression) remains among the most serious challenges for the habilitation of persons with intellectual disabilities and is a significant obstacle to community integration. The current standard of behavior analytic treatment for problem behavior in this population consists of a functional assessment and treatment model. Within that model, the first step is to assess the behavior–environment relations that give rise to and maintain problem behavior, a functional behavioral assessment. Conventional methods of assessing behavioral function include indirect, descriptive, and experimental assessments of problem behavior. Clinical investigators have produced a rich literature demonstrating the relative effectiveness for each method, but in clinical practice, each can produce ambiguous or difficult-to-interpret outcomes that may impede treatment development. This paper outlines potential sources of variability in assessment outcomes and then reviews the evidence on strategies for avoiding ambiguous outcomes and/or clarifying initially ambiguous results. The end result for each assessment method is a set of best practice guidelines, given the available evidence, for conducting the initial assessment. PMID:26236145

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

    PubMed Central

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

    2015-01-01

    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. PMID:25601848

  17. Precise Point Positioning with Partial Ambiguity Fixing

    PubMed Central

    Li, Pan; Zhang, Xiaohong

    2015-01-01

    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. PMID:26067196

  18. Ambiguity in sentence processing.

    PubMed

    Altmann, G T

    1998-04-01

    As listeners and readers, we rarely notice the ambiguities that pervade our everyday language. When we hear the proverb `Time flies like an arrow' we might ponder its meaning, but not the fact that there are almost 100 grammatically permissible interpretations of this short sentence. On occasion, however, we do notice sentential ambiguity: headlines, such as `Two Sisters Reunited After 18 Years in Checkout Counter', are amusing because they so consistently lead to the unintended interpretation (presumably, the sisters did not spend 18 years at the checkout). It is this consistent preference for one interpretation-and one grammatical structure-rather than another that has fuelled research into sentence processing for more than 20 years. Until relatively recently, the dominant belief had been that these preferences arise from general principles that underlie our use of grammar, with certain grammatical constructions being preferred over others. There has now accrued, however, a considerable body of evidence demonstrating that these preferences are not absolute, but can change in particular circumstances. With this evidence have come new theories of sentence processing, some of which, at first glance, radically question the standard notions of linguistic representation, grammar and understanding.

  19. The ambiguous neutron

    NASA Astrophysics Data System (ADS)

    Hawes, Joan L.

    1980-09-01

    The ways in which a neutron may be described suggest that it is a particle; is a wave; has no electric charge; has a spin magnetic moment similar to that of an electron and a proton; is a stable fundamental unit of matter; and has a halflife of approximately 12 min. These are only some of the seemingly ambiguous properties of a very remarkable entity. Mostly-the machinations of wave mechanics notwithstanding-there seems little doubt that the neutron is imagined to be a particle. It is probably regarded as a very small, round, invisible object which has no electric charge and resides in the atomic nucleus. Indeed, the fact that without it stable nuclei cannot exist seems paradoxically allied to the statement that neither can radioactive ones. Again, a certain ambiguity is evident in the notion that any electrically neutral entity can show magnetic properties. And, if it is the force effects of the neutron that underline its role as a fundamental building brick of matter, how does it exert these forces and remain uncharged? Many of the solutions to these and other questions and propositions about the neutron are of relatively recent history; some still remain hidden-the precise nature of the neutron's forces of interaction for example. But the search to understanding lies in the same realm of patient experimental and theoretical enquiry that embodied its initial discovery by James Chadwick in 1932.

  20. Selection mechanisms in reading lexically ambiguous words.

    PubMed

    Rayner, K; Frazier, L

    1989-09-01

    Readers' eye movements were monitored as they read sentences containing lexically ambiguous words. The ambiguous words were either biased (one strongly dominant interpretation) or nonbiased. Readers' gaze durations were longer on nonbiased than biased words when the disambiguating information followed the target word. In Experiment 1, reading times on the disambiguating word did not differ whether the disambiguation followed the target word immediately or occurred several words later. In Experiment 2, prior disambiguation eliminated the long gaze durations on nonbiased target words but resulted in long gaze durations on biased target words if the context demanded the subordinate meaning. The results indicate that successful integration of one meaning with prior context terminates the search for alternative meanings of that word. This results in selective (single meaning) access when integration of a dominant meaning is fast (due to a biasing context) and identification of a subordinate meaning is slow (a strongly biased ambiguity with a low-frequency meaning).

  1. Rats are sensitive to ambiguity.

    PubMed

    Fast, Cynthia D; Blaisdell, Aaron P

    2011-12-01

    In the present study, we investigated response decisions made under conditions of incomplete information in rats. In Experiment 1, rats were trained on either a positive patterning (PP; A-, B-, AB+) or a negative patterning (NP; A+, B+, AB-) instrumental lever-press discrimination. Subjects that had learned an NP discrimination responded less to Cue A when Cue B was covered at test. The cover did not, however, affect test responses to Cue A in the PP condition. In Experiment 2, rats received concurrent training on both PP and NP discriminations. After concurrent training, responses to Cue A were different with B covered versus uncovered for both NP and PP discriminations. We discuss possible accounts for why exposure to a nonlinearly soluble discrimination (NP) may have affected sensitivity to cue ambiguity produced by the cover. These results have interesting implications for representational processes engaged in problem solving.

  2. Ambiguous Loss Experienced by Transnational Mexican Immigrant Families.

    PubMed

    Solheim, Catherine; Zaid, Samantha; Ballard, Jaime

    2016-06-01

    In this study, an ambiguous loss framework as described by Boss (1999, Ambiguous loss: Learning to live with unresolved grief, First Harvard University Press, Cambridge, MA) was used to examine and understand the family experiences of Mexican immigrant agricultural workers in Minnesota. Transcripts from interviews with 17 workers in Minnesota and 17 family members in Mexico were analyzed using qualitative methodology to identify experiences of ambiguous loss in the participants' narratives. Key dimensions of ambiguous loss identified in the transcripts include: psychological family, feelings of chronic/recurring loss, finding support, and meaning making. In the category of psychological family, participants in both Mexico and the United States mourned the physical absence of their family members and experienced ambiguity regarding family responsibilities, but worked to maintain their psychological roles within the family. In the category of chronic/recurring loss, participants in both countries experienced chronic worry from not knowing if family members were safe, ambiguity regarding when the immigrant would return, and chronic stressors that compounded these feelings of loss. Participants in both countries coped with both real and ambiguous losses by accessing family support and by using ambiguous communication to minimize worry. Participants in Mexico also accessed work and community-based support. Participants in both countries made meaning of the ambiguous loss by identifying ways their lives were improved and goals were met as a result of the immigration for agricultural work in Minnesota. PMID:25619113

  3. Ambiguous Loss Experienced by Transnational Mexican Immigrant Families.

    PubMed

    Solheim, Catherine; Zaid, Samantha; Ballard, Jaime

    2016-06-01

    In this study, an ambiguous loss framework as described by Boss (1999, Ambiguous loss: Learning to live with unresolved grief, First Harvard University Press, Cambridge, MA) was used to examine and understand the family experiences of Mexican immigrant agricultural workers in Minnesota. Transcripts from interviews with 17 workers in Minnesota and 17 family members in Mexico were analyzed using qualitative methodology to identify experiences of ambiguous loss in the participants' narratives. Key dimensions of ambiguous loss identified in the transcripts include: psychological family, feelings of chronic/recurring loss, finding support, and meaning making. In the category of psychological family, participants in both Mexico and the United States mourned the physical absence of their family members and experienced ambiguity regarding family responsibilities, but worked to maintain their psychological roles within the family. In the category of chronic/recurring loss, participants in both countries experienced chronic worry from not knowing if family members were safe, ambiguity regarding when the immigrant would return, and chronic stressors that compounded these feelings of loss. Participants in both countries coped with both real and ambiguous losses by accessing family support and by using ambiguous communication to minimize worry. Participants in Mexico also accessed work and community-based support. Participants in both countries made meaning of the ambiguous loss by identifying ways their lives were improved and goals were met as a result of the immigration for agricultural work in Minnesota.

  4. P300 and Decision Making under Risk and Ambiguity

    PubMed Central

    Wang, Lei; Zheng, Jiehui; Huang, Shenwei; Sun, Haoye

    2015-01-01

    Our study aims to contrast the neural temporal features of early stage of decision making in the context of risk and ambiguity. In monetary gambles under ambiguous or risky conditions, 12 participants were asked to make a decision to bet or not, with the event-related potentials (ERPs) recorded meantime. The proportion of choosing to bet in ambiguous condition was significantly lower than that in risky condition. An ERP component identified as P300 was found. The P300 amplitude elicited in risky condition was significantly larger than that in ambiguous condition. The lower bet rate in ambiguous condition and the smaller P300 amplitude elicited by ambiguous stimuli revealed that people showed much more aversion in the ambiguous condition than in the risky condition. The ERP results may suggest that decision making under ambiguity occupies higher working memory and recalls more past experience while decision making under risk mainly mobilizes attentional resources to calculate current information. These findings extended the current understanding of underlying mechanism for early assessment stage of decision making and explored the difference between the decision making under risk and ambiguity. PMID:26539213

  5. P300 and Decision Making under Risk and Ambiguity.

    PubMed

    Wang, Lei; Zheng, Jiehui; Huang, Shenwei; Sun, Haoye

    2015-01-01

    Our study aims to contrast the neural temporal features of early stage of decision making in the context of risk and ambiguity. In monetary gambles under ambiguous or risky conditions, 12 participants were asked to make a decision to bet or not, with the event-related potentials (ERPs) recorded meantime. The proportion of choosing to bet in ambiguous condition was significantly lower than that in risky condition. An ERP component identified as P300 was found. The P300 amplitude elicited in risky condition was significantly larger than that in ambiguous condition. The lower bet rate in ambiguous condition and the smaller P300 amplitude elicited by ambiguous stimuli revealed that people showed much more aversion in the ambiguous condition than in the risky condition. The ERP results may suggest that decision making under ambiguity occupies higher working memory and recalls more past experience while decision making under risk mainly mobilizes attentional resources to calculate current information. These findings extended the current understanding of underlying mechanism for early assessment stage of decision making and explored the difference between the decision making under risk and ambiguity. PMID:26539213

  6. AmbiguityVis: Visualization of Ambiguity in Graph Layouts.

    PubMed

    Wang, Yong; Shen, Qiaomu; Archambault, Daniel; Zhou, Zhiguang; Zhu, Min; Yang, Sixiao; Qu, Huamin

    2016-01-01

    Node-link diagrams provide an intuitive way to explore networks and have inspired a large number of automated graph layout strategies that optimize aesthetic criteria. However, any particular drawing approach cannot fully satisfy all these criteria simultaneously, producing drawings with visual ambiguities that can impede the understanding of network structure. To bring attention to these potentially problematic areas present in the drawing, this paper presents a technique that highlights common types of visual ambiguities: ambiguous spatial relationships between nodes and edges, visual overlap between community structures, and ambiguity in edge bundling and metanodes. Metrics, including newly proposed metrics for abnormal edge lengths, visual overlap in community structures and node/edge aggregation, are proposed to quantify areas of ambiguity in the drawing. These metrics and others are then displayed using a heatmap-based visualization that provides visual feedback to developers of graph drawing and visualization approaches, allowing them to quickly identify misleading areas. The novel metrics and the heatmap-based visualization allow a user to explore ambiguities in graph layouts from multiple perspectives in order to make reasonable graph layout choices. The effectiveness of the technique is demonstrated through case studies and expert reviews.

  7. The Effect of the Case Method on Tolerance for Ambiguity.

    ERIC Educational Resources Information Center

    Banning, Kevin C.

    2003-01-01

    Of students in capstone strategic management classes, 195 (experimental group) were instructed using the case method. Compared with results from 42 controls on a tolerance for ambiguity scale, the case method not only conveyed core concepts but also increased tolerance. Locus of control had an effect on learning to tolerate ambiguity. (Contains 21…

  8. Giving behavior of millionaires.

    PubMed

    Smeets, Paul; Bauer, Rob; Gneezy, Uri

    2015-08-25

    This paper studies conditions influencing the generosity of wealthy people. We conduct incentivized experiments with individuals who have at least €1 million in their bank account. The results show that millionaires are more generous toward low-income individuals in a giving situation when the other participant has no power, than in a strategic setting, where the other participant can punish unfair behavior. Moreover, the level of giving by millionaires is higher than in any other previous study. Our findings have important implications for charities and financial institutions that deal with wealthy individuals. PMID:26261327

  9. Giving behavior of millionaires

    PubMed Central

    Smeets, Paul; Bauer, Rob; Gneezy, Uri

    2015-01-01

    This paper studies conditions influencing the generosity of wealthy people. We conduct incentivized experiments with individuals who have at least €1 million in their bank account. The results show that millionaires are more generous toward low-income individuals in a giving situation when the other participant has no power, than in a strategic setting, where the other participant can punish unfair behavior. Moreover, the level of giving by millionaires is higher than in any other previous study. Our findings have important implications for charities and financial institutions that deal with wealthy individuals. PMID:26261327

  10. Giving behavior of millionaires.

    PubMed

    Smeets, Paul; Bauer, Rob; Gneezy, Uri

    2015-08-25

    This paper studies conditions influencing the generosity of wealthy people. We conduct incentivized experiments with individuals who have at least €1 million in their bank account. The results show that millionaires are more generous toward low-income individuals in a giving situation when the other participant has no power, than in a strategic setting, where the other participant can punish unfair behavior. Moreover, the level of giving by millionaires is higher than in any other previous study. Our findings have important implications for charities and financial institutions that deal with wealthy individuals.

  11. SAR peculiarities, ambiguities and constraints

    NASA Astrophysics Data System (ADS)

    Keydel, Wolfgang

    1992-08-01

    A synthetic aperture radar (SAR) is basically a coherent scatterometer that employs a coherent real aperture radar with highly sophisticated data evaluation and image processing capabilities. Therefore, the coherence of the system is very important; furthermore, the keypoints for SAR are data storage, evaluation, and processing. These facts entail peculiarities of SAR and special ambiguities which are different from those arising with real aperture radar (RAR). The objective of this paper is to point out the special peculiarities and ambiguities of SAR in comparison to the corresponding properties of RAR. Main topics in this connection are as follows: basic peculiarities like range dependency of signal to noise ratio; azimuth resolution; influence of platform velocity; range and azimuth ambiguities; pulse repetition frequency limitations; velocity effects; and phase error influence, on SAR-image, that can cause motion compensation problems. All these effects will be explained together with different contrast-equations between the target and clutter signals of SAR and RAR.

  12. Association ambiguity management in mixed data dimension tracking problems

    NASA Astrophysics Data System (ADS)

    Thornbrue, James R.; Knight, J. Nate; Slocumb, Benjamin J.

    2010-04-01

    Association and fusion of passive direction finding (DF) reports with active radar tracks from airborne targets is challenging because of the low dimensionality of the common kinematic measurement space. Often, multi-target scenarios lead to significant data association ambiguity. Classically, the approach to this problem is a simple hypothesis test wherein a batch of DF sensor measurements is associated with either zero or one of the radar tracks; assignment of multiple DF tracks to a single radar track is allowed without regard to compatibility, and this can lead to detrimental results. This paper develops a new approach for managing the ambiguity. The problem is formulated as a two-dimensional assignment, and any association ambiguity is determined from the k best solutions. Firm association decisions are made only when the ambiguity is at an acceptable level. The ambiguity information is also available in real time as an output to the system operator. An improved batch association score, relative to previous works, is formulated that addresses statistical correlations between individual measurement-to-track residuals; this new score is a likelihood ratio generated from Kalman Filter residuals. Where previous scoring methods lead to incorrect ambiguity assessments in certain scenarios, the new approach yields accurate results. Because the score is recursive, the batch may be extended over an arbitrary number of measurements, helping to manage association ambiguities over time. Simulation results are shown to demonstrate the algorithm.

  13. Lexical Access for Phonetic Ambiguities.

    ERIC Educational Resources Information Center

    Spencer, N. J.; Wollman, Neil

    1980-01-01

    Reports on research that (1) suggests that phonetically ambiguous pairs (ice cream/I scream) have been used inaccurately to illustrate contextual effects in word segmentation, (2) supports unitary rather than exhaustive processing, and (3) supports the use of the concepts of word frequency and listener expectations instead of top-down, multiple…

  14. Ambiguity Resolution in Lateralized Arabic

    ERIC Educational Resources Information Center

    Hayadre, Manar; Kurzon, Dennis; Peleg, Orna; Zohar, Eviatar

    2015-01-01

    We examined ambiguity resolution in reading in Arabic. Arabic is an abjad orthography and is morphologically similar to Hebrew. However, Arabic literacy occurs in a diglossic context, and its orthography is more visually complex than Hebrew. We therefore tested to see whether hemispheric differences will be similar or different from previous…

  15. Text Association Analysis and Ambiguity in Text Mining

    NASA Astrophysics Data System (ADS)

    Bhonde, S. B.; Paikrao, R. L.; Rahane, K. U.

    2010-11-01

    Text Mining is the process of analyzing a semantically rich document or set of documents to understand the content and meaning of the information they contain. The research in Text Mining will enhance human's ability to process massive quantities of information, and it has high commercial values. Firstly, the paper discusses the introduction of TM its definition and then gives an overview of the process of text mining and the applications. Up to now, not much research in text mining especially in concept/entity extraction has focused on the ambiguity problem. This paper addresses ambiguity issues in natural language texts, and presents a new technique for resolving ambiguity problem in extracting concept/entity from texts. In the end, it shows the importance of TM in knowledge discovery and highlights the up-coming challenges of document mining and the opportunities it offers.

  16. GNSS carrier phase ambiguity resolution based on integrity restriction in ambiguity domain

    NASA Astrophysics Data System (ADS)

    Liu, Haiying; Chen, Zhiming; Ye, Weisong; Wang, Huinan

    2014-04-01

    Carrier phase ambiguity resolution of Global Navigation Satellite System (GNSS) is a key technology for high-precision navigation and positioning, and it is a challenge for applications which require both high accuracy and high integrity. This paper proposes efficient ambiguity resolution methods based on integrity restriction using Fixed Failure rate Ratio Test (FF-RT) and Doubly Non-central F-distribution Ratio Test (DNF-RT), and derives the related processing models and numerical algorithms compared with the traditional Ratio Test (RT) method. Firstly, the integer ambiguity resolution and validation procedures, especially the Least squares AMBiguity Decorrelation Adjustment (LAMBDA) estimation and RT validation are analyzed. Then the quality evaluation using success rate, the FF-RT method using Integer Aperture (IA) estimation and the NDF-RT method are proposed. Lastly, the simulation and analysis for LAMBDA using RT, FF-RT and DNF-RT methods are performed. Simulation results show that in case of unbiased scenario FF-RT and DNF-RT have similar performances, which are significantly better than RT. In case of biased scenario it is difficult for FF-RT to predict the biased success rate thus it should not be used for bias detection, while DNF-RT can detect biases in most cases except for the biases are approximate or equal to integer, which has the important benefit for early detection of potential threat to the position solution.

  17. [Grandchildren in family care giving for people with dementia: experiences and evaluations--results from a life-world-oriented study].

    PubMed

    Philipp-Metzen, H E

    2011-12-01

    Dementia often has a serious impact on family life in household care giving situations. The qualitative study in applied gerontology presented here focuses on the subjective experiences of grandchildren and the intergenerational relationships of the family members. It includes 15 in-depth retrospective interviews with young adults (11 female, 4 male). The theoretical background is a sociological life-world-oriented approach by Alfred Schütz. The grandchildren reported a wide range of experiences with positive and enriching incidents prevailing, e.g., individual and familial competence in care giving, increased contact between family members, i.e., so-called"family cohesion", improvements in the grandchildren's social responsibility, and their acquired knowledge of the needs of older people and of persons with dementia. Individual stress was experienced because of so-called "challenging behavior" by the grandparents (e.g., aggressive behavior) or family circumstances when the demands were too great.A third category includes those experiences which seem to be "taken for granted" and are regarded as insignificant by the grandchildren. Because this category encompasses many of the grandchildren's own care giving activities, the widespread assumption that dementia must always cause younger carers stress is not true in general. The data suggest that living in a family that has difficulties in coping with the situation might be more demanding than dealing with the behavior and psychological symptoms of dementia. The grandchildren should be given access to age-appropriate information about the disease and the ways to communicate effectively with their grandparent needing care. PMID:21909775

  18. How do speakers avoid ambiguous linguistic expressions?

    PubMed

    Ferreira, Victor S; Slevc, L Robert; Rogers, Erin S

    2005-07-01

    Three experiments assessed how speakers avoid linguistically and nonlinguistically ambiguous expressions. Speakers described target objects (a flying mammal, bat) in contexts including foil objects that caused linguistic (a baseball bat) and nonlinguistic (a larger flying mammal) ambiguity. Speakers sometimes avoided linguistic-ambiguity, and they did so equally regardless of whether they also were about to describe foils. This suggests that comprehension processes can sometimes detect linguistic-ambiguity before producing it. However, once produced, speakers consistently avoided using the same linguistically ambiguous expression again for a different meaning. This suggests that production processes can successfully detect linguistic-ambiguity after-the-fact. Speakers almost always avoided nonlinguistic-ambiguity. Thus, production processes are especially sensitive to nonlinguistic- but not linguistic-ambiguity, with the latter avoided consistently only once it is already articulated.

  19. Sensory memory for ambiguous vision.

    PubMed

    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.

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

    PubMed

    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.

  1. [A neonate with ambiguous genitalia].

    PubMed

    Jansen, Burgo J; van Rijn, Rick R; van Trotsenburg, A S P Paul

    2015-01-01

    In a neonate with ambiguous genitalia, physical examination revealed a phallus. Ultrasonography showed a vagina and uterus, but no gonads. Because of severe undervirilisation in the presence of a uterus, probably due to 46,XY gonadal dysgenesis, parents were advised female sex assignment. When after a few weeks the phallus had increased in size, abdominal laparoscopy showed an underdeveloped uterus. Gonadal biopsy confirmed gonadal dysgenesis. Sex assignment was reconsidered and changed into the male gender. PMID:26200425

  2. Resolving Phase Ambiguities In OQPSK

    NASA Technical Reports Server (NTRS)

    Nguyen, Tien M.

    1991-01-01

    Improved design for modulator and demodulator in offset-quaternary-phase-key-shifting (OQPSK) communication system enables receiver to resolve ambiguity in estimated phase of received signal. Features include unique-code-word modulation and detection and digital implementation of Costas loop in carrier-recovery subsystem. Enchances performance of carrier-recovery subsystem, reduces complexity of receiver by removing redundant circuits from previous design, and eliminates dependence of timing in receiver upon parallel-to-serial-conversion clock.

  3. Productive Ambiguity in the Learning of Mathematics

    ERIC Educational Resources Information Center

    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…

  4. How Do Speakers Avoid Ambiguous Linguistic Expressions?

    ERIC Educational Resources Information Center

    Ferreira, V.S.; Slevc, L.R.; Rogers, E.S.

    2005-01-01

    Three experiments assessed how speakers avoid linguistically and nonlinguistically ambiguous expressions. Speakers described target objects (a flying mammal, bat) in contexts including foil objects that caused linguistic (a baseball bat) and nonlinguistic (a larger flying mammal) ambiguity. Speakers sometimes avoided linguistic-ambiguity, and they…

  5. Implications of Ambiguity for Scientometric Measurement.

    ERIC Educational Resources Information Center

    Bookstein, A.

    2001-01-01

    The essence of Scientomatics is precise measurement. Yet the measurements made in Scientometric research are steeped in ambiguity. This article explores the nature of ambiguity in measurement, probes for mechanisms that allow regularities to be discovered in an environment in which ambiguity is pronounced, and describes Lotka's law (often used to…

  6. Where Does Sociopragmatic Ambiguity Come From?

    ERIC Educational Resources Information Center

    Burt, Susan Meredith

    Sociopragmatic ambiguity (SPA) is claimed here to differ from other, better-known types of ambiguity, in terms of its locus, cause, and effect. SPA is characteristic of whole-discourse features rather than of lexical items or phrases. The ambiguity is one of social rather than ideational or semantic meaning. It is claimed that SPA arises through…

  7. Ambiguity and Uncertainty in Probabilistic Inference.

    ERIC Educational Resources Information Center

    Einhorn, Hillel J.; Hogarth, Robin M.

    1985-01-01

    A descriptive model of how people make judgments under ambiguity is proposed. Two factors are reflected in the model: (1) the amount of ambiguity, which affects the size of the simulation, and (2) one's attitudes toward ambiguity. The model is tested in four experiments using individual and group analyses. (Author/LMO)

  8. Generative Learning: Adults Learning within Ambiguity

    ERIC Educational Resources Information Center

    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…

  9. Selection of wrist posture in conditions of motor ambiguity.

    PubMed

    Wood, Daniel K; Goodale, Melvyn A

    2011-02-01

    In our everyday motor interactions with objects, we often encounter situations where the features of an object are determinate (i.e., not perceptually ambiguous), but the mapping between those features and appropriate movement patterns is indeterminate, resulting in a lack of any clear preference for one posture over another. We call this indeterminacy in stimulus-response mapping 'motor ambiguity'. Here, we use a grasping task to investigate the decision mechanisms that mediate the basic behavior of selecting one wrist posture over another in conditions of motor ambiguity. Using one of two possible wrist postures, participants grasped a dowel that was presented at various orientations. At most orientations, there was a clear preference for one wrist posture over the other. Within a small range of orientations, however, participants were variable in their posture selection due to the fact that the dowel was ambiguous with respect to the hand posture it afforded. We observed longer reaction times (RT) during 'ambiguous' trials than during the 'unambiguous' trials. In two subsequent experiments, we explored the effects of foreknowledge and trial history on the selection of wrist posture. We found that foreknowledge led to shorter RT unless the previous trial involved selecting a posture in the ambiguous region, in which case foreknowledge gave no RT advantage. These results are discussed within the context of existing models of sensorimotor decision making. PMID:21152907

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

    PubMed

    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

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

    PubMed

    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.

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

    PubMed Central

    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

  13. Combined GPS/GLONASS precise point positioning with fixed GPS ambiguities.

    PubMed

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

    2014-09-18

    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.

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

    PubMed Central

    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

  15. Adapting to an Uncertain World: Cognitive Capacity and Causal Reasoning with Ambiguous Observations

    PubMed Central

    Shou, Yiyun; Smithson, Michael

    2015-01-01

    Ambiguous causal evidence in which the covariance of the cause and effect is partially known is pervasive in real life situations. Little is known about how people reason about causal associations with ambiguous information and the underlying cognitive mechanisms. This paper presents three experiments exploring the cognitive mechanisms of causal reasoning with ambiguous observations. Results revealed that the influence of ambiguous observations manifested by missing information on causal reasoning depended on the availability of cognitive resources, suggesting that processing ambiguous information may involve deliberative cognitive processes. Experiment 1 demonstrated that subjects did not ignore the ambiguous observations in causal reasoning. They also had a general tendency to treat the ambiguous observations as negative evidence against the causal association. Experiment 2 and Experiment 3 included a causal learning task requiring a high cognitive demand in which paired stimuli were presented to subjects sequentially. Both experiments revealed that processing ambiguous or missing observations can depend on the availability of cognitive resources. Experiment 2 suggested that the contribution of working memory capacity to the comprehensiveness of evidence retention was reduced when there were ambiguous or missing observations. Experiment 3 demonstrated that an increase in cognitive demand due to a change in the task format reduced subjects’ tendency to treat ambiguous-missing observations as negative cues. PMID:26468653

  16. Management of ambiguities in magnetostratigraphic correlation

    NASA Astrophysics Data System (ADS)

    Charreau, J.; Lallier, F.; Antoine, C.; Caumon, G.; Ruiu, J.

    2012-12-01

    Magnetostratigraphy is a powerful tool to provide absolute dating of sediments enabling good and detailed chronostratigraphic correlations. It is based on the correlation of a magnetic polarity column, observed and measured in a given sediment section, to a magnetic polarity reference scale where polarity changes are well dated via other independent methods. However, magnetostratigraphic correlations are loose because only constrained by binary magnetic chrons (i.e normal or reversal) and their thickness, which are both defined from depth variations of the magnetic remanent directions. The thickness of a given magnetic chron is a function of time and sediment accumulation rate, which may not be stationary, leading to ambiguities when performing the correlations. To address these ambiguities, a numerical method based on the Dynamic Time Warping algorithm is proposed. Magnetostratigraphics correlation are computed in order to minimize the local variation of accumulation rate. The main advantage of the proposed method is to automatically provide a set of reasonably likely correlations. This set can then be scrutinized for further analysis and interpretation. However, the likelihood of a correlation should be handled carefully. It depends on the information content of the magnetotratigraphic section itself and remain ultimately valid by ancillary constraint. Nevertheless, the method is shown to present consistent results on difficult synthetic cases simulating abrupt variations of the sedimentation rate, and provides interesting insights on true sections debated by previous authors.

  17. Breaking the indexing ambiguity in serial crystallography.

    PubMed

    Brehm, Wolfgang; Diederichs, Kay

    2014-01-01

    In serial crystallography, a very incomplete partial data set is obtained from each diffraction experiment (a `snapshot'). In some space groups, an indexing ambiguity exists which requires that the indexing mode of each snapshot needs to be established with respect to a reference data set. In the absence of such re-indexing information, crystallographers have thus far resorted to a straight merging of all snapshots, yielding a perfectly twinned data set of higher symmetry which is poorly suited for structure solution and refinement. Here, two algorithms have been designed for assembling complete data sets by clustering those snapshots that are indexed in the same way, and they have been tested using 15,445 snapshots from photosystem I [Chapman et al. (2011), Nature (London), 470, 73-77] and with noisy model data. The results of the clustering are unambiguous and enabled the construction of complete data sets in the correct space group P63 instead of (twinned) P6322 that researchers have been forced to use previously in such cases of indexing ambiguity. The algorithms thus extend the applicability and reach of serial crystallography.

  18. Resolving distance ambiguities towards 6.7 GHz methanol masers

    NASA Astrophysics Data System (ADS)

    Pandian, J. D.; Momjian, E.; Goldsmith, P. F.

    2008-07-01

    Context: Distances to most star forming regions are determined using kinematics, through the assumption that the observed radial velocity arises from the motion of the source with respect to the Sun resulting from the differential rotation of Galaxy. The primary challenge associated with the application of this technique in the inner Galaxy is the kinematic distance ambiguity. Aims: In this work, we aim to resolve the kinematic distance ambiguity towards a sample of 6.7 GHz methanol masers, which are signposts of the early stages of massive star formation. Methods: We measured 21 cm H I absorption spectra using the Very Large Array in C and CnB configurations. A comparison of the maximum velocity of H I absorption with the source velocity and tangent point velocity was used to resolve the kinematic distance ambiguity. Results: We resolved the distance ambiguity towards 41 sources. Distance determinations that are in conflict with previous measurements are discussed. The NE2001 spiral arm model is broadly consistent with the locations of the star forming complexes. We find that the use of vertical scale height arguments to resolve the distance ambiguity can lead to erroneous classifications for a significant fraction of sources.

  19. Possible ambiguities in the equation of state for neutron stars

    SciTech Connect

    Cheoun, Myung-Ki; Miyatsu, Tsuyoshi; Ryu, C. Y.; Deliduman, Cemsinan; Güngör, Can; Keleş, Vildan; Kajino, Toshitaka; Mathews, Grant J.

    2014-05-02

    We addressed possible ambiguities on the properties of neutron stars (NSs) estimated in theoretical sides. First, roles of hyperons inside the NS are discussed through various relativistic mean field (RMF) theories. In particular, the extension of SU(6) spin-flavor symmetry to SU(3) flavor symmetry is shown to give rise to the increase of hyperon threshold density, similarly to the Fock term effects in RMF theories. As a result, about 2.0 solar mass is obtained with the hyperons. Second, the effect by the modified f(R) gravity, which leaves a room for the dark energy in the Einstein equation to be taken into account, is discussed for the NS in a strong magnetic field (MF). Our results show that the modified gravity with the Kaluza-Klein electro-magnetism theory expanded in terms of a length scale parameter may reasonably describe the NS in strong MF, so called magnetar. Even the super-soft equation of state is shown to be revived by the modified f(R) gravity.

  20. Giving effective poster presentations

    SciTech Connect

    Rice, J A

    1998-08-27

    Giving an effective poster presentation can be easy and rewarding with attention to a few proven concepts. Define your audience. Keep the words and graphics clear, concise, and eye-catching. Remember, you have three seconds to attract attention and 30 seconds to get your message across.

  1. Neural Correlates of Semantic Competition during Processing of Ambiguous Words

    PubMed Central

    Bilenko, Natalia Y.; Grindrod, Christopher M.; Myers, Emily B.; Blumstein, Sheila E.

    2010-01-01

    The current study investigated the neural correlates that underlie the processing of ambiguous words and the potential effects of semantic competition on that processing. Participants performed speeded lexical decisions on semantically related and unrelated prime-target pairs presented in the auditory modality. The primes were either ambiguous words (e.g., ball) or unambiguous words (e.g., athlete), and targets were either semantically related to the dominant (i.e., most frequent) meaning of the ambiguous prime word (e.g., soccer) or to the subordinate (i.e., less frequent) meaning (e.g., dance). Results showed increased activation in the bilateral inferior frontal gyrus (IFG) for ambiguous related compared to unambiguous related stimulus pairs, demonstrating that prefrontal areas are activated even in an implicit task where participants are not required to explicitly analyze the semantic content of the stimuli and to make an overt selection of a particular meaning based on this analysis. Additionally, increased activation was found in the left IFG and the left cingulate gyrus for subordinate meaning compared to dominant meaning conditions, suggesting that additional resources are recruited in order to resolve increased competition demands in accessing the subordinate meaning of an ambiguous word. PMID:18702579

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

    PubMed

    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

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

    PubMed Central

    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

  4. At the crossroads of race: racial ambiguity and biracial identification influence psychological essentialist thinking.

    PubMed

    Young, Danielle M; Sanchez, Diana T; Wilton, Leigh S

    2013-10-01

    Racial essentialism refers to the widely held belief that race is a biological, stable, and natural category. Although research finds very little evidence that race has biological underpinnings, racial essentialist beliefs persist and are linked to negative outgroup consequences. This study initially demonstrates that label and visual ambiguity concurrently inform racial categorization. It then tests whether exposure to racially ambiguous targets (a) challenges essentialism when ambiguous targets are labeled with biracial categories and (b) reinforces essentialism when ambiguous targets identify with monoracial categories. The results showed that White perceivers (N = 84) who were exposed to racially ambiguous, biracially labeled targets showed reductions in their essentialist thinking about race, whereas perceivers who were exposed to racially ambiguous, monoracially labeled targets showed increases in their essentialist beliefs.

  5. The effect of context on responses to racially ambiguous faces: changes in perception and evaluation.

    PubMed

    Willadsen-Jensen, Eve; Ito, Tiffany A

    2015-07-01

    Reactions to individuals who possess features associated with multiple racial groups may be particularly susceptible to external contextual influences, leading to meaningfully different racial perceptions and judgments in different situations. In the present study, we found that an extrinsic race-label cue not only changed evaluative associations activated by a racially ambiguous face, but also changed quickly occurring neural responses sensitive to racial perception. Behaviorally, prototypical Black faces and racially ambiguous faces labeled as Black activated more negative implicit associations than prototypical White faces and racially ambiguous faces labeled as White. Neurally, prototypical faces and racially ambiguous faces cued with the same race elicited similar responses. Specifically, prototypical Black and racially ambiguous faces labeled as Black elicited larger P200s but smaller N200s than prototypical White and racially ambiguous faces labeled as White. These results show that racial perception can be changed by an external cue and this, in turn, influences subsequent evaluative reactions. PMID:25344946

  6. Giving through life insurance

    NASA Astrophysics Data System (ADS)

    Reed, John C.

    Your Union's Gift Steering Committee has pointed out from time to time various methods of contributing to the Union that may provide certain members with the satisfaction of recognizing the value and attainments of the organization, and the part it played in the individual's career, combined with a maximum of convenience as well as tax and other advantages. One such method is to make the Union a beneficiary of one or more life insurance policies.The committee recently learned of an example of such giving that seems so pertinent to the committee's thinking that it is here called to the attention of the membership. The example is a gift to The George Washington University (GW) and was discussed in some detail on page 3 of the November 1982 GW Times under the heading ‘Getting and Giving: Carol Brosnari's Story.’

  7. Passive coherent location FPGA implementation of the cross ambiguity function

    NASA Astrophysics Data System (ADS)

    Kvasnička, Michal; Heřmánek, Antonín; Kuneš, Michal; Pelant, Martin; Plšek, Radek

    2006-02-01

    One of key problem in passive coherent location (PCL) is effective and accurate computation of the cross ambiguity function (CAF). This function is related to the direct signal and signals reflected from localized targets. PCL systems exploit high-power commercial transmitters of opportunity (FM, TV, etc.) to take advantage of lower frequencies, multistatic geometries and covert deployment. The transmitter does not have to cooperate with the receiver. The CAF represent power spectral density distribution of the cross-correlation between direct and reflected signals. It depends on mutual time delay and frequency shift of the input signals and is considerate as primary information for detection, localization and identification of the tracked targets. Regarding above mentioned reasons has to be important develop optimal (numerically effective and sufficiently accurate) implementation of the HW architecture based on FPGA for CAF computation, which will be suitable for future real-time PCL systems. As a first result which originates on the ongoing mutual cooperation between ERA a.s. and UTIA is design of the PC accelerator card for CAF computation based on Xilinx FPGA processor. The presented contribution gives overall information about used algorithms, FPGA accelerator card design and achieved performance. The future possibilities of the additional enhancements are discussed.

  8. Value transfer contributes to ambiguous-cue discrimination learning.

    PubMed

    Urcuioli, Peter J; Michalek, Sarah

    2007-08-01

    Pigeons learned two concurrent simultaneous discriminations in which the S- for one served as the S+ for the other. When all correct choices were reinforced, accuracy on the former (positive vs. ambiguous-cue or PA) discrimination was lower than on the latter (negative vs. ambiguous-cue or NA) discrimination. When correct choices on the PA discrimination were intermittently reinforced, however, pigeons chose the S- more often than the S+ on those trials. By contrast, intermittently reinforcing correct choices on the NA discrimination did not affect NA-trial accuracy but yielded higher PA-trial accuracy relative to continuous reinforcement. Together with a separate preference assessment, these results indicate that value transfer, in which some of the positive value accrued by an S+ transfers to its companion S-, contributes to ambiguous-cue performances.

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

    PubMed

    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.

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

    PubMed

    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. PMID:25280165

  11. Value transfer contributes to ambiguous-cue discrimination learning.

    PubMed

    Urcuioli, Peter J; Michalek, Sarah

    2007-08-01

    Pigeons learned two concurrent simultaneous discriminations in which the S- for one served as the S+ for the other. When all correct choices were reinforced, accuracy on the former (positive vs. ambiguous-cue or PA) discrimination was lower than on the latter (negative vs. ambiguous-cue or NA) discrimination. When correct choices on the PA discrimination were intermittently reinforced, however, pigeons chose the S- more often than the S+ on those trials. By contrast, intermittently reinforcing correct choices on the NA discrimination did not affect NA-trial accuracy but yielded higher PA-trial accuracy relative to continuous reinforcement. Together with a separate preference assessment, these results indicate that value transfer, in which some of the positive value accrued by an S+ transfers to its companion S-, contributes to ambiguous-cue performances. PMID:17972729

  12. Ambiguous Words Are Harder to Learn

    ERIC Educational Resources Information Center

    Degani, Tamar; Tokowicz, Natasha

    2010-01-01

    Relatively little is known about the role of ambiguity in adult second-language learning. In this study, native English speakers learned Dutch-English translation pairs that either mapped in a one-to-one fashion (unambiguous items) in that a Dutch word uniquely corresponded to one English word, or mapped in a one-to-many fashion (ambiguous items),…

  13. The Communicative Function of Ambiguity in Language

    ERIC Educational Resources Information Center

    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…

  14. Sequence data - Magnitude and implications of some ambiguities.

    NASA Technical Reports Server (NTRS)

    Holmquist, R.; Jukes, T. H.

    1972-01-01

    A stochastic model is applied to the divergence of the horse-pig lineage from a common ansestor in terms of the alpha and beta chains of hemoglobin and fibrinopeptides. The results are compared with those based on the minimum mutation distance model of Fitch (1972). Buckwheat and cauliflower cytochrome c sequences are analyzed to demonstrate their ambiguities. A comparative analysis of evolutionary rates for various proteins of horses and pigs shows that errors of considerable magnitude are introduced by Glx and Asx ambiguities into evolutionary conclusions drawn from sequences of incompletely analyzed proteins.

  15. Give/Take

    SciTech Connect

    2007-09-12

    Give and Take are set of companion utilities that allow a secure transfer of files from one user to another without exposing the files to third parties. The named files are copied to a spool area. The reciever can retrieve the files by running the "take" program. Ownership of the files remains with the giver until they are taken. Certain users may be limited to take files only from specific givers. For these users, files may only be taken from givers who are members of the gt-uid-group where uid is the UNIX id of the limited user.

  16. Give/Take

    2007-09-12

    Give and Take are set of companion utilities that allow a secure transfer of files from one user to another without exposing the files to third parties. The named files are copied to a spool area. The reciever can retrieve the files by running the "take" program. Ownership of the files remains with the giver until they are taken. Certain users may be limited to take files only from specific givers. For these users, filesmore » may only be taken from givers who are members of the gt-uid-group where uid is the UNIX id of the limited user.« less

  17. A Two-Dimensional Variational Analysis Method for NSCAT Ambiguity Removal: Methodology, Sensitivity, and Tuning

    NASA Technical Reports Server (NTRS)

    Hoffman, R. N.; Leidner, S. M.; Henderson, J. M.; Atlas, R.; Ardizzone, J. V.; Bloom, S. C.; Atlas, Robert (Technical Monitor)

    2001-01-01

    In this study, we apply a two-dimensional variational analysis method (2d-VAR) to select a wind solution from NASA Scatterometer (NSCAT) ambiguous winds. 2d-VAR determines a "best" gridded surface wind analysis by minimizing a cost function. The cost function measures the misfit to the observations, the background, and the filtering and dynamical constraints. The ambiguity closest in direction to the minimizing analysis is selected. 2d-VAR method, sensitivity and numerical behavior are described. 2d-VAR is compared to statistical interpolation (OI) by examining the response of both systems to a single ship observation and to a swath of unique scatterometer winds. 2d-VAR is used with both NSCAT ambiguities and NSCAT backscatter values. Results are roughly comparable. When the background field is poor, 2d-VAR ambiguity removal often selects low probability ambiguities. To avoid this behavior, an initial 2d-VAR analysis, using only the two most likely ambiguities, provides the first guess for an analysis using all the ambiguities or the backscatter data. 2d-VAR and median filter selected ambiguities usually agree. Both methods require horizontal consistency, so disagreements occur in clumps, or as linear features. In these cases, 2d-VAR ambiguities are often more meteorologically reasonable and more consistent with satellite imagery.

  18. Improving integer ambiguity resolution for GLONASS precise orbit determination

    NASA Astrophysics Data System (ADS)

    Liu, Yang; Ge, Maorong; Shi, Chuang; Lou, Yidong; Wickert, Jens; Schuh, Harald

    2016-08-01

    The frequency division multiple access adopted in present GLONASS introduces inter-frequency bias (IFB) at the receiver-end both in code and phase observables, which makes GLONASS ambiguity resolution rather difficult or even not available, especially for long baselines up to several thousand kilometers. This is one of the major reasons that GLONASS could hardly reach the orbit precision of GPS, both in terms of consistency among individual International GNSS Service (IGS) analysis centers and discontinuity at the overlapping day boundaries. Based on the fact that the GLONASS phase IFB is similar on L1 and L2 bands in unit of length and is a linear function of the frequency number, several approaches have been developed to estimate and calibrate the IFB for integer ambiguity resolution. However, they are only for short and medium baselines. In this study, a new ambiguity resolution approach is developed for GLONASS global networks. In the approach, the phase ambiguities in the ionosphere-free linear combination are directly transformed with a wavelength of about 5.3 cm, according to the special frequency relationship of GLONASS L1 and L2 signals. After such transformation, the phase IFB rate can be estimated and corrected precisely and then the corresponding double-differenced ambiguities can be directly fixed to integers even for baselines up to several thousand kilometers. To evaluate this approach, experimental validations using one-month data of a global network with 140 IGS stations was carried out for GLONASS precise orbit determination. The results show that the GLONASS double-difference ambiguity resolution for long baselines could be achieved with an average fixing-rate of 91.4 %. Applying the fixed ambiguities as constraints, the GLONASS orbit overlapping RMS at the day boundaries could be reduced by 37.2 % in ideal cases and with an averaged reduction of about 21.4 %, which is comparable with that by the GPS ambiguity resolution. The orbit improvement is

  19. Processing Deliberate Ambiguity in Newspaper Headlines: Double Grounding

    ERIC Educational Resources Information Center

    Brone, Geert; Coulson, Seana

    2010-01-01

    Two experiments investigated the processing and appreciation of double grounding, a form of intentional ambiguity often used in the construction of headlines. For example, in "Russia takes the froth off Carlsberg results," the key element, "takes the froth off," is significant both metaphorically, where it refers to the detrimental impact of…

  20. Death: 'nothing' gives insight.

    PubMed

    Ettema, Eric J

    2013-08-01

    According to a widely accepted belief, we cannot know our own death--death means 'nothing' to us. At first sight, the meaning of 'nothing' just implies the negation or absence of 'something'. Death then simply refers to the negation or absence of life. As a consequence, however, death has no meaning of itself. This leads to an ontological paradox in which death is both acknowledged and denied: death is … nothing. In this article, I investigate whether insight into the ontological paradox of the nothingness of death can contribute to a good end-of-life. By analysing Aquinas', Heidegger's and Derrida's understanding of death as nothingness, I explore how giving meaning to death on different ontological levels connects to, and at the same time provides resistance against, the harsh reality of death. By doing so, I intend to demonstrate that insight into the nothingness of death can count as a framework for a meaningful dealing with death.

  1. Role Ambiguity and Self-Efficacy: The Moderating Effects of Goal Orientation and Procedural Justice

    ERIC Educational Resources Information Center

    Li, Andrew; Bagger, Jessica

    2008-01-01

    The present study investigated variables that moderated the relationship between role ambiguity and self-efficacy. Results of a field study found support for the moderating role of learning goal orientation, such that the relationship between role ambiguity and self-efficacy was weaker when learning goal orientation was high. In addition, we found…

  2. Persistence of Initial Misanalysis With No Referential Ambiguity.

    PubMed

    Nakamura, Chie; Arai, Manabu

    2016-05-01

    Previous research reported that in processing structurally ambiguous sentences comprehenders often preserve an initial incorrect analysis even after adopting a correct analysis following structural disambiguation. One criticism is that the sentences tested in previous studies involved referential ambiguity and allowed comprehenders to make inferences about the initial interpretation using pragmatic information, suggesting the possibility that the initial analysis persisted due to comprehenders' pragmatic inference but not to their failure to perform complete reanalysis of the initial misanalysis. Our study investigated this by testing locally ambiguous relative clause sentences in Japanese, in which the initial misinterpretation contradicts the correct interpretation. Our study using a self-paced reading technique demonstrated evidence for the persistence of the initial analysis with this structure. The results from an eye-tracking study further suggested that the phenomenon directly reflected the amount of support given to the initial incorrect analysis prior to disambiguating information: The more supported the incorrect main clause analysis was, the more likely comprehenders were to preserve the analysis even after the analysis was falsified. Our results thus demonstrated that the preservation of the initial analysis occurs not due to referential ambiguities but to comprehenders' difficulty to fully revise the highly supported initial interpretation.

  3. The interaction of visual and linguistic saliency during syntactic ambiguity resolution.

    PubMed

    Coco, Moreno I; Keller, Frank

    2015-01-01

    Psycholinguistic research using the visual world paradigm has shown that the processing of sentences is constrained by the visual context in which they occur. Recently, there has been growing interest in the interactions observed when both language and vision provide relevant information during sentence processing. In three visual world experiments on syntactic ambiguity resolution, we investigate how visual and linguistic information influence the interpretation of ambiguous sentences. We hypothesize that (1) visual and linguistic information both constrain which interpretation is pursued by the sentence processor, and (2) the two types of information act upon the interpretation of the sentence at different points during processing. In Experiment 1, we show that visual saliency is utilized to anticipate the upcoming arguments of a verb. In Experiment 2, we operationalize linguistic saliency using intonational breaks and demonstrate that these give prominence to linguistic referents. These results confirm prediction (1). In Experiment 3, we manipulate visual and linguistic saliency together and find that both types of information are used, but at different points in the sentence, to incrementally update its current interpretation. This finding is consistent with prediction (2). Overall, our results suggest an adaptive processing architecture in which different types of information are used when they become available, optimizing different aspects of situated language processing. PMID:25176109

  4. Emolabeling effectively reduces the influence of ambiguous labeling on food packages among grocery store shoppers.

    PubMed

    Privitera, Gregory J; Brown, Caitlin J; Gillespie, James J

    2014-12-16

    Despite increased regulations and policy enforcement for nutrition labeling, ambiguous labels on food items can still have deleterious effects on consumer perceptions of health. The present study used a counterbalanced within-subjects design to test if emolabeling - the use of emoticons to convey health information (happy = healthy; sad = not healthy) - will reduce the effects of ambiguous labels on consumer perceptions of the healthfulness of a food item. 85 grocery store shoppers were shown nutrition labels for a low calorie (LC) and a high calorie (HC) food with/without emolabels, and with an ambiguous label that either implied the food was healthy or unhealthy. Results showed that emolabels reduced the effectiveness of ambiguous labels: consumers rated the LC food as healthier and the HC food as less healthy when emolabels were added. The results suggest that, if implemented, this image-based emolabeling system could possibly be an effective buffer against the use of ambiguous labeling by food manufacturers.

  5. Emolabeling effectively reduces the influence of ambiguous labeling on food packages among grocery store shoppers.

    PubMed

    Privitera, Gregory J; Brown, Caitlin J; Gillespie, James J

    2015-01-01

    Despite increased regulations and policy enforcement for nutrition labeling, ambiguous labels on food items can still have deleterious effects on consumer perceptions of health. The present study used a counterbalanced within-subjects design to test if emolabeling - the use of emoticons to convey health information (happy = healthy; sad = not healthy) - will reduce the effects of ambiguous labels on consumer perceptions of the healthfulness of a food item. 85 grocery store shoppers were shown nutrition labels for a low calorie (LC) and a high calorie (HC) food with/without emolabels, and with an ambiguous label that either implied the food was healthy or unhealthy. Results showed that emolabels reduced the effectiveness of ambiguous labels: consumers rated the LC food as healthier and the HC food as less healthy when emolabels were added. The results suggest that, if implemented, this image-based emolabeling system could possibly be an effective buffer against the use of ambiguous labeling by food manufacturers. PMID:25946913

  6. GNSS integer ambiguity validation based on posterior probability

    NASA Astrophysics Data System (ADS)

    Wu, Zemin; Bian, Shaofeng

    2015-10-01

    GNSS integer ambiguity validation is considered to be a challenge task for decades. Several kinds of validation tests are developed and widely used in these years, but theoretical basis is their weakness. Ambiguity validation theoretically is an issue of hypothesis test. In the frame of Bayesian hypothesis testing, posterior probability is the canonical standard that statistical decision should be based on. In this contribution, (i) we derive the posterior probability of the fixed ambiguity based on the Bayesian principle and modify it for practice ambiguity validation. (ii) The optimal property of the posterior probability test is proved based on an extended Neyman-Pearson lemma. Since validation failure rate is the issue users most concerned about, (iii) we derive the failure rate upper bound of the posterior probability test, so the user can use the posterior probability test either in the fixed posterior probability or in the fixed failure rate way. Simulated as well as real observed data are used for experimental validations. The results show that (i) the posterior probability test is the most effective within the R-ratio test, difference test, ellipsoidal integer aperture test and posterior probability test, (ii) the posterior probability test is computational efficient and (iii) the failure rate estimation for posterior probability test is useful.

  7. Recommendations for reducing ambiguity in written procedures.

    SciTech Connect

    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.

  8. Probability judgments under ambiguity and conflict

    PubMed Central

    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. PMID:26042081

  9. Event ambiguity fuels the effective spread of rumors

    NASA Astrophysics Data System (ADS)

    Xu, Jiuping; Zhang, Yi

    2015-08-01

    In this paper, a new rumor spreading model which quantifies a specific rumor spreading feature is proposed. The specific feature focused on is the important role the event ambiguity plays in the rumor spreading process. To study the impact of this event ambiguity on the spread of rumors, the probability p(t) that an individual becomes a rumor spreader from an initially unaware person at time t is built. p(t) reflects the extent of event ambiguity, and a parameter c of p(t) is used to measure the speed at which the event moves from ambiguity to confirmation. At the same time, a principle is given to decide on the correct value for parameter c A rumor spreading model is then developed with this function added as a parameter to the traditional model. Then, several rumor spreading model simulations are conducted with different values for c on both regular networks and ER random networks. The simulation results indicate that a rumor spreads faster and more broadly when c is smaller. This shows that if events are ambiguous over a longer time, rumor spreading appears to be more effective, and is influenced more significantly by parameter c in a random network than in a regular network. We then determine parameters of this model through data fitting of the missing Malaysian plane, and apply this model to an analysis of the missing Malaysian plane. The simulation results demonstrate that the most critical time for authorities to control rumor spreading is in the early stages of a critical event.

  10. Learning the Language of Evolution: Lexical Ambiguity and Word Meaning in Student Explanations

    NASA Astrophysics Data System (ADS)

    Rector, Meghan A.; Nehm, Ross H.; Pearl, Dennis

    2013-06-01

    Our study investigates the challenges introduced by students' use of lexically ambiguous language in evolutionary explanations. Specifically, we examined students' meaning of five key terms incorporated into their written evolutionary explanations: pressure, select, adapt, need, and must. We utilized a new technological tool known as the Assessment Cascade System (ACS) to investigate the frequency with which biology majors spontaneously used lexically ambiguous language in evolutionary explanations, as well as their definitions and explanations of what they meant when they used such terms. Three categories of language were identified and examined in this study: terms with Dual Ambiguity, Incompatible Ambiguity, and Unintended Ambiguity. In the sample of 1282 initial evolutionary explanations, 81 % of students spontaneously incorporated lexically ambiguous language at least once. Furthermore, the majority of these initial responses were judged to be inaccurate from a scientific point of view. While not significantly related to gender, age, or reading/writing ability, students' use of contextually appropriate evolutionary language ( pressure and adapt) was significantly associated with academic performance in biology. Comparisons of initial responses to follow-up responses demonstrated that the majority of student explanations were not reinterpreted after consideration of the follow-up response; nevertheless, a sizeable minority was interpreted differently. Most cases of interpretation change were a consequence of resolving initially ambiguous responses, rather than a change of accuracy, resulting in an increased understanding of students' evolutionary explanations. We discuss a series of implications of lexical ambiguity for evolution education.

  11. Relative efficiency of ambiguous vs. directly measured haplotype frequencies.

    PubMed

    Schaid, Daniel J

    2002-11-01

    Haplotypes are useful for both fine-mapping of susceptibility loci and evaluation of sequence variation at multiple sites along a chromosome. However, they are difficult to directly measure over long stretches of DNA in diploid organisms. Consequently, multiple genetic markers are typically measured, without linkage phase information, giving rise to a subject's diplotype. From diplotype data, haplotypes are often inferred by pedigree information, or treated as partially missing data when haplotype frequencies are estimated among unrelated subjects. This latter ambiguity can increase the variance of the estimated haplotype frequencies. Douglas et al. ([2001] Nat. Genet. 28:361-364) recently quantified the relative efficiency of estimating haplotype frequencies from the diplotypes of unrelated subjects, relative to directly measured haplotypes via somatic cell hybrids (conversion technology), and demonstrated that unknown linkage phase can lead to a large loss of efficiency. However, their results were based on linkage equilibrium among marker loci, which may not be realistic for closely linked markers. We extend their relative efficiency calculations by several aspects: 1) allowance for linkage disequilbrium (LD) among marker loci; 2) evaluation of different patterns of LD; and 3) evaluation of nuclear families with and without parents. We show that although the loss in efficiency of haplotype frequencies among unrelated subjects decreases as LD increases to its maximum value, the general conclusions of Douglas et al. ([2001] Nat. Genet. 28:361-364) hold true for a variety of LD patterns and magnitudes. However, our results also demonstrate that trios of parents+one child are highly efficient for haplotype frequency estimation, that additional children offer little information, and that siblings without parents can be grossly inefficient. Genet. Epidemiol. 23:426-443, 2002. PMID:12432508

  12. Dealing With Uncertainty: Testing Risk- and Ambiguity-Attitude Across Adolescence.

    PubMed

    Blankenstein, Neeltje E; Crone, Eveline A; van den Bos, Wouter; van Duijvenvoorde, Anna C K

    2016-01-01

    Attitudes to risk (known probabilities) and attitudes to ambiguity (unknown probabilities) are separate constructs that influence decision making, but their development across adolescence remains elusive. We administered a choice task to a wide adolescent age-range (N = 157, 10-25 years) to disentangle risk- and ambiguity-attitudes using a model-based approach. Additionally, this task was played in a social context, presenting choices from a high risk-taking peer. We observed age-related changes in ambiguity-attitude, but not risk-attitude. Also, ambiguity-aversion was negatively related to real-life risk taking. Finally, the social context influenced only risk-attitudes. These results highlight the importance of disentangling risk- and ambiguity-attitudes in adolescent risk taking.

  13. Dealing With Uncertainty: Testing Risk- and Ambiguity-Attitude Across Adolescence.

    PubMed

    Blankenstein, Neeltje E; Crone, Eveline A; van den Bos, Wouter; van Duijvenvoorde, Anna C K

    2016-01-01

    Attitudes to risk (known probabilities) and attitudes to ambiguity (unknown probabilities) are separate constructs that influence decision making, but their development across adolescence remains elusive. We administered a choice task to a wide adolescent age-range (N = 157, 10-25 years) to disentangle risk- and ambiguity-attitudes using a model-based approach. Additionally, this task was played in a social context, presenting choices from a high risk-taking peer. We observed age-related changes in ambiguity-attitude, but not risk-attitude. Also, ambiguity-aversion was negatively related to real-life risk taking. Finally, the social context influenced only risk-attitudes. These results highlight the importance of disentangling risk- and ambiguity-attitudes in adolescent risk taking. PMID:27028162

  14. European starlings unriddle the ambiguous-cue problem.

    PubMed

    Vasconcelos, Marco; Monteiro, Tiago

    2014-01-01

    The ambiguous-cue problem is deceptively simple. It involves two concurrently trained simultaneous discriminations (known as PA and NA trials), but only three stimuli. Stimulus A is common to both discriminations, but serves as non-reinforced stimulus (S-) on PA trials and as reinforced stimulus (S+) on NA trials. Typically, animals' accuracy is lower on PA trials-the ambiguous-cue effect. We conducted two experiments with European starlings (Sturnus vulgaris) using Urcuioli and Michalek's (2007, Psychon B Rev 14, 658-662) experimental manipulations as a springboard to test the predictions of two of the most important theoretical accounts of the effect: the interfering cue hypothesis and value transfer theory. Both experiments included two groups of birds, one trained with a regular ambiguous-cue problem (Group Continuous) and another trained with partial reinforcement on PA trials (Group PA-Partial). The experiments differed only in the number of sessions (18 vs. 36) and daily trials (360 vs. 60). As previously observed, we found faster acquisition on NA trials than on PA trials in both experiments, but by the end of training PA performance was surprisingly high, such that no ambiguous-cue effect was present in Group Continuous of either experiment. The effect was still present in both PA-Partial groups, but to a smaller degree than expected. These findings are inconsistent with the literature, in particular with the results of Urcuioli and Michalek (2007) with pigeons, and question the aforementioned theoretical accounts as complete explanations of the ambiguous-cue effect. In our view, to achieve such high levels of accuracy on PA trials, starlings must have attended to configural (i.e., contextual) cues, thus differentiating stimulus A when presented on PA trials from stimulus A when presented on NA trials. A post hoc simulation of a reinforcement-based configural model supported our assertion.

  15. Improved PPP ambiguity resolution by COES FCB estimation

    NASA Astrophysics Data System (ADS)

    Li, Yihe; Gao, Yang; Shi, Junbo

    2016-05-01

    Precise point positioning (PPP) integer ambiguity resolution is able to significantly improve the positioning accuracy with the correction of fractional cycle biases (FCBs) by shortening the time to first fix (TTFF) of ambiguities. When satellite orbit products are adopted to estimate the satellite FCB corrections, the narrow-lane (NL) FCB corrections will be contaminated by the orbit's line-of-sight (LOS) errors which subsequently affect ambiguity resolution (AR) performance, as well as positioning accuracy. To effectively separate orbit errors from satellite FCBs, we propose a cascaded orbit error separation (COES) method for the PPP implementation. Instead of using only one direction-independent component in previous studies, the satellite NL improved FCB corrections are modeled by one direction-independent component and three directional-dependent components per satellite in this study. More specifically, the direction-independent component assimilates actual FCBs, whereas the directional-dependent components are used to assimilate the orbit errors. To evaluate the performance of the proposed method, GPS measurements from a regional and a global network are processed with the IGSReal-time service (RTS), IGS rapid (IGR) products and predicted orbits with >10 cm 3D root mean square (RMS) error. The improvements by the proposed FCB estimation method are validated in terms of ambiguity fractions after applying FCB corrections and positioning accuracy. The numerical results confirm that the obtained FCBs using the proposed method outperform those by conventional method. The RMS of ambiguity fractions after applying FCB corrections is reduced by 13.2 %. The position RMSs in north, east and up directions are reduced by 30.0, 32.0 and 22.0 % on average.

  16. Raising Expectations, Giving Hope

    ERIC Educational Resources Information Center

    Principal Leadership, 2005

    2005-01-01

    "Hold school!" was the directive that Principal Patricia Ashmore received from the deputy superintendent of Madison County Schools when she was appointed to Velma Jackson Magnet High School five years ago. The explicit instruction came as a direct result of looking at student achievement, attendance, and graduation data that confirmed the need to…

  17. Film as a Lens for Teaching Culture: Balancing Concepts, Ambiguity, and Paradox.

    ERIC Educational Resources Information Center

    Mallinger, Mark; Rossy, Gerard

    2003-01-01

    Discusses how to apply dimensions of an integrated cultural framework (ability to influence, comfort with ambiguity, achievement orientation, individualism/collectivism, time orientation, space orientation) to analysis of films as part of the study of culture. Gives an application example and selection guidelines and discusses limitations. (SK)

  18. Survivable VON mapping with ambiguity similitude for differentiable maximum shared capacity in elastic optical networks

    NASA Astrophysics Data System (ADS)

    Yang, Hui; Zhu, Xiaoxu; Bai, Wei; Zhao, Yongli; Zhang, Jie; Liu, Zhu; Zhou, Ziguan; Ou, Qinghai

    2016-09-01

    Virtualization is considered to be a promising solution to support various emerging applications. This paper illustrates the problem of virtual mapping from a new perspective, and mainly focuses on survivable mapping of virtual networks and the potential trade-off between spectral resource usage effectiveness and failure resilience level. We design an optimum shared protection mapping (OSPM) scheme in elastic optical networks. A differentiable maximum shared capacity of each frequency slot is defined to more efficiently shared protection resource. In order to satisfy various assessment standards, a metric called ambiguity similitude is defined for the first time to give insight on the optimizing difficulty. Simulation results are presented to compare the outcome of the novel OSPM algorithm with traditional dedicated link protection and maximum shared protection mapping. By synthetic analysis, OSPM outperforms the other two schemes in terms of striking a perfect balance among blocking probability, resources utilization, protective success rate, and spectrum redundancy.

  19. How the owl resolves auditory coding ambiguity.

    PubMed

    Mazer, J A

    1998-09-01

    The barn owl (Tyto alba) uses interaural time difference (ITD) cues to localize sounds in the horizontal plane. Low-order binaural auditory neurons with sharp frequency tuning act as narrow-band coincidence detectors; such neurons respond equally well to sounds with a particular ITD and its phase equivalents and are said to be phase ambiguous. Higher-order neurons with broad frequency tuning are unambiguously selective for single ITDs in response to broad-band sounds and show little or no response to phase equivalents. Selectivity for single ITDs is thought to arise from the convergence of parallel, narrow-band frequency channels that originate in the cochlea. ITD tuning to variable bandwidth stimuli was measured in higher-order neurons of the owl's inferior colliculus to examine the rules that govern the relationship between frequency channel convergence and the resolution of phase ambiguity. Ambiguity decreased as stimulus bandwidth increased, reaching a minimum at 2-3 kHz. Two independent mechanisms appear to contribute to the elimination of ambiguity: one suppressive and one facilitative. The integration of information carried by parallel, distributed processing channels is a common theme of sensory processing that spans both modality and species boundaries. The principles underlying the resolution of phase ambiguity and frequency channel convergence in the owl may have implications for other sensory systems, such as electrolocation in electric fish and the computation of binocular disparity in the avian and mammalian visual systems. PMID:9724807

  20. Boundary Ambiguity in Remarriage: Does Ambiguity Differentiate Degree of Marital Adjustment and Interaction?

    ERIC Educational Resources Information Center

    Pasley, B. Kay; Ihinger-Tallman, Marilyn

    1989-01-01

    Examined differences between 216 spouses in remarriages classified as having low or high boundary ambiguity. Found high boundary ambiguity to be more prevalent in certain types of remarriages (stepmother families with nonresidential children). Few significant differences were found when wives were compared with wives and husbands with husbands in…

  1. Preliminary validation of the Spanish version of the Multiple Stimulus Types Ambiguity Tolerance Scale (MSTAT-II).

    PubMed

    Arquero, José L; McLain, David L

    2010-05-01

    Despite widespread interest in ambiguity tolerance and other information-related individual differences, existing measures are conceptually dispersed and psychometrically weak. This paper presents the Spanish version of MSTAT-II, a short, stimulus-oriented, and psychometrically improved measure of an individual's orientation toward ambiguous stimuli. Results obtained reveal adequate reliability, validity, and temporal stability. These results support the use of MSTAT-II as an adequate measure of ambiguity tolerance.

  2. Charitable giving expenditures and the faith factor.

    PubMed

    Showers, Vince E; Showers, Linda S; Beggs, Jeri M; Cox, James E

    2011-01-01

    Using a permanent income hypothesis approach and an income-giving status interaction effect, a double hurdle model provides evidence of significant differences from the impact of household income and various household characteristics on both a household's likelihood of giving and its level of giving to religion, charity, education, others outside the household, and politics. An analysis of resulting income elasticity estimates revealed that households consider religious giving a necessity good at all levels of income, while other categories of giving are generally found to be luxury goods. Further, those who gave to religion were found to give more to education and charity then those not giving to religion, and higher education households were more likely to give to religion than households with less education. This analysis suggests that there may be more to religious giving behavior than has been assumed in prior studies and underscores the need for further research into the motivation for religious giving. Specifically, these findings point to an enduring, internal motivation for giving rather than an external, “What do I get for what I give,” motive. PMID:21322897

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

    PubMed Central

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

    2016-01-01

    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. PMID:27222361

  4. Mentoring relationships and the levels of role conflict and role ambiguity experienced by novice nursing faculty.

    PubMed

    Specht, Jennifer A

    2013-01-01

    This study explored the effect of mentoring on the levels of role conflict and role ambiguity experienced by novice nursing faculty related to their transitions into academe using a descriptive, comparative design. It also measured the relationship between the quality of mentoring experiences of novice nursing faculty and their levels of role conflict and role ambiguity using a correlational design. P. Benner's (1984) novice to expert model was utilized as a framework for successful role transition. J. R. Rizzo, R. J. House, and S. I. Lirtzman's (1970) role conflict and role ambiguity scale was used to measure the levels of role conflict and role ambiguity experienced by novice nursing faculty. Results indicate that participants (n = 224) who were mentored have significantly lower levels of role conflict (M = 3.57) and role ambiguity (M = 3.02) than those who were not mentored (M = 4.62 and M = 3.90, respectively). Also significant, the higher the participants' reported levels of quality of mentoring experiences were, the lower their levels of role conflict and role ambiguity were. The results of this study indicate that mentoring eases the transition of novice nursing faculty from practice into academe by decreasing the degree of role ambiguity and role conflict that they experience.

  5. Interpretation bias in responses to ambiguous cues in pain patients.

    PubMed

    Pincus, T; Pearce, S; McClelland, A; Farley, S; Vogel, S

    1994-05-01

    Pain patients and control subjects responses to ambiguous cues were compared in two separate investigations. In the first, pain patients, control subjects and physiotherapists were asked to produce a list of spontaneous associations to ambiguous cues (such as terminal and growth). To control for mood effects the experiment was repeated with three more groups: Pain patients, osteopaths and a control group. Measures of anxiety and depression were incorporated in the analysis. Results indicate that pain patients systematically produce more pain related associations than the other groups, and that this effect is independent of anxiety and depression levels. The discussion concentrates on the implications of these findings both for the theory of pain processing and for clinical interventions.

  6. Decoding of depth and motion in ambiguous binocular perception.

    PubMed

    Sakai, Ko; Ogiya, Mitsuharu; Hirai, Yuzo

    2011-07-01

    We have shown previously that random dots with an interocular time delay (ITD), the time difference of the onset of dots between the two eyes, yield both apparent depth and motion, although depth and velocity are covariant and, thus, ITD is inherently ambiguous. The depth of random dots with ITD was proportional to ITD, suggesting that the visual system assumes a constant velocity of the dots and determines depth on the basis of this constant velocity. We performed psychophysical experiments to investigate whether subjects perceive a constant velocity with a variety of ITDs in random dots aligned along a single vertical line that ensures neither apparent motion nor accidental disparity between the dots. The results showed that subjects perceive a constant velocity for a variety of ITDs with simultaneous perception of depth in proportion to ITD, indicating the priority of depth over velocity in ambiguous binocular perception derived from ITD.

  7. Smelling directions: olfaction modulates ambiguous visual motion perception.

    PubMed

    Kuang, Shenbing; Zhang, Tao

    2014-07-23

    Senses of smells are often accompanied by simultaneous visual sensations. Previous studies have documented enhanced olfactory performance with concurrent presence of congruent color- or shape- related visual cues, and facilitated visual object perception when congruent smells are simultaneously present. These visual object-olfaction interactions suggest the existences of couplings between the olfactory pathway and the visual ventral processing stream. However, it is not known if olfaction can modulate visual motion perception, a function that is related to the visual dorsal stream. We tested this possibility by examining the influence of olfactory cues on the perceptions of ambiguous visual motion signals. We showed that, after introducing an association between motion directions and olfactory cues, olfaction could indeed bias ambiguous visual motion perceptions. Our result that olfaction modulates visual motion processing adds to the current knowledge of cross-modal interactions and implies a possible functional linkage between the olfactory system and the visual dorsal pathway.

  8. Sensitivity to Referential Ambiguity in Discourse: The Role of Attention, Working Memory, and Verbal Ability

    PubMed Central

    Boudewyn, Megan A.; Long, Debra L.; Traxler, Matthew J.; Lesh, Tyler A.; Dave, Shruti; Mangun, George R.; Carter, Cameron S.; Swaab, Tamara Y.

    2016-01-01

    The establishment of reference is essential to language comprehension. The goal of this study was to examine listeners’ sensitivity to referential ambiguity as a function of individual variation in attention, working memory capacity, and verbal ability. Participants listened to stories in which two entities were introduced that were either very similar (e.g., two oaks) or less similar (e.g., one oak and one elm). The manipulation rendered an anaphor in a subsequent sentence (e.g., oak) ambiguous or unambiguous. EEG was recorded as listeners comprehended the story, after which participants completed tasks to assess working memory, verbal ability, and the ability to use context in task performance. Power in the alpha and theta frequency bands when listeners received critical information about the discourse entities (e.g., oaks) was used to index attention and the involvement of the working memory system in processing the entities. These measures were then used to predict an ERP component that is sensitive to referential ambiguity, the Nref, which was recorded when listeners received the anaphor. Nref amplitude at the anaphor was predicted by alpha power during the earlier critical sentence: Individuals with increased alpha power in ambiguous compared with unambiguous stories were less sensitive to the anaphor's ambiguity. Verbal ability was also predictive of greater sensitivity to referential ambiguity. Finally, increased theta power in the ambiguous compared with unambiguous condition was associated with higher working-memory span. These results highlight the role of attention and working memory in referential processing during listening comprehension. PMID:26401815

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

    PubMed

    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.

  10. The effect of stereotypical primes on the neural processing of racially ambiguous faces.

    PubMed

    Dickter, Cheryl L; Kittel, Julie A

    2012-01-01

    Previous research has demonstrated that an early attentional component of the event-related potential (ERP), the P2, is sensitive to the distinction between the processing of racial outgroup and ingroup faces but may not be sensitive to the distinction between racially ambiguous and ingroup faces. Recent behavioral work, however, has suggested that contextual information may affect the processing of racially ambiguous faces. Thus, the first goal of this study was to examine whether the early neural processing of racially ambiguous faces would be affected by primed stereotypes. White college student participants (n = 29) completed a task in which they racially categorized monoracial Black and White faces and racially ambiguous Black-White morphs. These faces were preceded by positive and negative Black and White stereotypical primes. Results indicated that P2 amplitude to the racially ambiguous faces was moderated by the valence of the primes such that negative primes led to greater neural processing of the racially ambiguous faces than positive primes. Furthermore, the extent to which P2 amplitude was affected by prime valence was moderated by individual differences in preference for structure and categorical thinking, as well as comfort with ambiguity.

  11. Phase-ambiguity resolution for QPSK modulation systems. Part 2: A method to resolve offset QPSK

    NASA Technical Reports Server (NTRS)

    Nguyen, Tien Manh

    1989-01-01

    Part 2 presents a new method to resolve the phase-ambiguity for Offset QPSK modulation systems. When an Offset Quaternary Phase-Shift-Keyed (OQPSK) communications link is utilized, the phase ambiguity of the reference carrier must be resolved. At the transmitter, two different unique words are separately modulated onto the quadrature carriers. At the receiver, the recovered carrier may have one of four possible phases, 0, 90, 180, or 270 degrees, referenced to the nominally correct phase. The IF portion of the channel may cause a phase-sense reversal, i.e., a reversal in the direction of phase rotation for a specified bit pattern. Hence, eight possible phase relationships (the so-called eight ambiguous phase conditions) between input and output of the demodulator must be resolved. Using the In-phase (I)/Quadrature (Q) channel reversal correcting property of an OQPSK Costas loop with integrated symbol synchronization, four ambiguous phase conditions are eliminated. Thus, only four possible ambiguous phase conditions remain. The errors caused by the remaining ambiguous phase conditions can be corrected by monitoring and detecting the polarity of the two unique words. The correction of the unique word polarities results in the complete phase-ambiguity resolution for the OQPSK system.

  12. Phase-ambiguity resolution for QPSK modulation systems. Part 2: A method to resolve offset QPSK

    NASA Astrophysics Data System (ADS)

    Nguyen, Tien Manh

    1989-05-01

    Part 2 presents a new method to resolve the phase-ambiguity for Offset QPSK modulation systems. When an Offset Quaternary Phase-Shift-Keyed (OQPSK) communications link is utilized, the phase ambiguity of the reference carrier must be resolved. At the transmitter, two different unique words are separately modulated onto the quadrature carriers. At the receiver, the recovered carrier may have one of four possible phases, 0, 90, 180, or 270 degrees, referenced to the nominally correct phase. The IF portion of the channel may cause a phase-sense reversal, i.e., a reversal in the direction of phase rotation for a specified bit pattern. Hence, eight possible phase relationships (the so-called eight ambiguous phase conditions) between input and output of the demodulator must be resolved. Using the In-phase (I)/Quadrature (Q) channel reversal correcting property of an OQPSK Costas loop with integrated symbol synchronization, four ambiguous phase conditions are eliminated. Thus, only four possible ambiguous phase conditions remain. The errors caused by the remaining ambiguous phase conditions can be corrected by monitoring and detecting the polarity of the two unique words. The correction of the unique word polarities results in the complete phase-ambiguity resolution for the OQPSK system.

  13. Determination and visualization of rotational ambiguity in four-component systems.

    PubMed

    Golshan, Azadeh; Maeder, Marcel; Abdollahi, Hamid

    2013-09-24

    One of the main problems that limit the use of model-free analysis methods for the resolution of multivariate data is that usually there is rotational ambiguity in the result. While methods for the complete definition of rotational ambiguity for two- and three-component systems have been published recently, the comprehensive and general resolution of rotational ambiguity for four-component systems has eluded chemists for several decades. We have developed an extension of self-modelling curve resolution for a mixture of four-components. The performance of the method was verified by applying it to resolve simulated and real data sets. PMID:24016578

  14. Doppler shift and ambiguity velocity caused by relative motion in quantum-enhanced measurement.

    PubMed

    Shen, Yanghe; Xu, Luping; Zhang, Hua; Yang, Peng

    2015-07-13

    We study the effect of relative motion on a frequency-entangled-based ranging scheme. Two major puzzles arise, i.e., Doppler shift and ambiguity velocity. During condition of rapid relative motion, Doppler shift invalidates the measurement result of this scheme; while during condition of slow relative motion, the ambiguity velocity turns into a major limitation. If relative speed between targets and measurement platform exceeds the ambiguity velocity, an accumulated profile obtained by the coincidence measurement will be distorted, which causes a lower ranging accuracy. Theoretical analysis shows a time-varying delay can be introduced to solve the two major puzzles. PMID:26191903

  15. Infants Interpret Ambiguous Requests for Absent Objects

    ERIC Educational Resources Information Center

    Saylor, Megan M.; Ganea, Patricia

    2007-01-01

    The current studies investigated 2 skills involved in 14- to 20-month-olds' ability to interpret ambiguous requests for absent objects: tracking others' experiences (Study 1) and representing links between speakers and object features across present and absent reference episodes (Study 2). In the basic task, 2 experimenters played separately with…

  16. The Development of Ambiguous Figure Perception

    ERIC Educational Resources Information Center

    Wimmer, Marina C.; Doherty, Martin J.

    2011-01-01

    Ambiguous figures have fascinated researchers for almost 200 years. The physical properties of these figures remain constant, yet two distinct interpretations are possible; these reverse (switch) from one percept to the other. The consensus is that reversal requires complex interaction of perceptual bottom-up and cognitive top-down elements. The…

  17. The Function of Ambiguity in Child Crises

    ERIC Educational Resources Information Center

    Stein, Myron

    1970-01-01

    Discusses the function of ambiguity" (an attitude of hatibual uncertainty, vagueness, and imprecision of communication) in crisis situations involving adult-child interchanges. Makes suggestions for medical and psychiatric counselors. Paper was presented at the meeting of the American Association of Psychiatric Clinics for Children, Boston,…

  18. Teachers' Burnout, Depression, Role Ambiguity and Conflict

    ERIC Educational Resources Information Center

    Papastylianou, Antonia; Kaila, Maria; Polychronopoulos, Michael

    2009-01-01

    The present study investigates issues associated with teachers' burnout in primary education as related to depression and role conflict-ambiguity. At the time of the study the participants (562 teachers) were working in seventy nine (79) Primary Education State Schools in Greece (Athens and two prefectures in the southern part of the country). The…

  19. Ambiguous figures: living versus nonliving objects.

    PubMed

    Verstijnen, Ilse M; Wagemans, Johan

    2004-01-01

    Eleven series of figures were studied, each series ranging from one extreme interpretation via five ambiguous intermediates to a second extreme interpretation. Triplets consisting of an ambiguous exemplar in the middle flanked on the left and right by its two extreme interpretations were presented to large groups of subjects. The initial aim was to establish the levels of perceptual ambiguity of each exemplar in a series, and normative data on the ambiguous figures are provided for future reference and use. However, several biases were encountered and these were examined in more detail. In experiment 1 the subject's task was to compare the middle figure with the flankers and draw an arrow from the middle figure towards the flanking extreme they judged the most similar. Here, an overall preference for the left extreme was found. Therefore the instructions were reversed in experiment 2; flankers had to be compared with the middle figure. The preference for the left extreme remained for figures of living objects, but for nonliving objects the preference switched to the right extreme. To do away with any effect of the arrows, in experiment 3 subjects were divided into two groups each receiving different instructions and were asked to circle one of the extremes. However, the pattern of biases remained the same. The bias found with figures of living objects may be explained on the basis of top-down processes. For nonliving figures, an hypothesis based on bottom-up processes like neural fatigue was considered but rejected. PMID:15250659

  20. Actions and Affordances in Syntactic Ambiguity Resolution

    ERIC Educational Resources Information Center

    Chambers, Craig G.; Tanenhaus, Michael K.; Magnuson, James S.

    2004-01-01

    In 2 experiments, eye movements were monitored as participants followed instructions containing temporary syntactic ambiguities (e.g., "Pour the egg in the bowl over the flour"). The authors varied the affordances of task-relevant objects with respect to the action required by the instruction (e.g., whether 1 or both eggs in the visual workspace…

  1. Ambiguity in Tactile Apparent Motion Perception

    PubMed Central

    Liaci, Emanuela; Bach, Michael; Tebartz van Elst, Ludger; Heinrich, Sven P.; Kornmeier, Jürgen

    2016-01-01

    Background 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. Methods 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. Results 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. Discussion 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

  2. Textbook presentations of weight: Conceptual difficulties and language ambiguities

    NASA Astrophysics Data System (ADS)

    Taibu, Rex; Rudge, David; Schuster, David

    2015-06-01

    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 for learners, especially for accelerating objects where the scale reading is different from the gravitational force. But while the underlying physical constructs behind the two referents for the term weight (and their relation to each other) are well understood scientifically, it is unclear how the concept of weight should be introduced to students and how the language ambiguities should be dealt with. We investigated treatments of weight in a sample of twenty introductory college physics textbooks, analyzing and coding their content based on the definition adopted, how the distinct constructs were dealt with in various situations, terminologies used, and whether and how language issues were handled. Results indicate that language-related issues, such as different, inconsistent, or ambiguous uses of the terms weight, "apparent weight," and "weightlessness," were prevalent both across and within textbooks. The physics of the related constructs was not always clearly presented, particularly for accelerating bodies such as astronauts in spaceships, and the language issue was rarely addressed. Our analysis of both literature and textbooks leads us to an instructional position which focuses on the physics constructs before introducing the term weight, and which explicitly discusses the associated language issues.

  3. Semantics and ambiguity of stochastic RNA family models.

    PubMed

    Giegerich, Robert; Höner zu Siederdissen, Christian

    2011-01-01

    Stochastic models, such as hidden Markov models or stochastic context-free grammars (SCFGs) can fail to return the correct, maximum likelihood solution in the case of semantic ambiguity. This problem arises when the algorithm implementing the model inspects the same solution in different guises. It is a difficult problem in the sense that proving semantic nonambiguity has been shown to be algorithmically undecidable, while compensating for it (by coalescing scores of equivalent solutions) has been shown to be NP-hard. For stochastic context-free grammars modeling RNA secondary structure, it has been shown that the distortion of results can be quite severe. Much less is known about the case when stochastic context-free grammars model the matching of a query sequence to an implicit consensus structure for an RNA family. We find that three different, meaningful semantics can be associated with the matching of a query against the model--a structural, an alignment, and a trace semantics. Rfam models correctly implement the alignment semantics, and are ambiguous with respect to the other two semantics, which are more abstract. We show how provably correct models can be generated for the trace semantics. For approaches, where such a proof is not possible, we present an automated pipeline to check post factum for ambiguity of the generated models. We propose that both the structure and the trace semantics are worth-while concepts for further study, possibly better suited to capture remotely related family members.

  4. A table of geometrical ambiguities in powder indexing obtained by exhaustive search.

    PubMed

    Oishi-Tomiyasu, R

    2016-01-01

    Geometrical ambiguity means the cases in which more than one powder indexing solution exists. Using a new function implemented in the powder indexing software CONOGRAPH, unit cells that involve geometrical ambiguity are exhaustively searched. As a result, many unknown cases are obtained, although the number of such unit cells is still rather limited. It is also proven that the number of solutions in powder auto-indexing is not always unique, but generally finite. PMID:26697869

  5. Charitable Giving by Married Couples Revisited

    ERIC Educational Resources Information Center

    Yoruk, Baris K.

    2010-01-01

    This paper investigates the effect of gender differences and household bargaining on charitable giving. I replicate the study of Andreoni, Brown, and Rischall (2003) using a different data set--the recently available Panel Study of Income Dynamics (PSID) supplement on charitable giving--and test the sensitivity of their results to inclusion of…

  6. Perceptions of boundary ambiguity in the process of leaving an abusive partner.

    PubMed

    Khaw, Lyndal; Hardesty, Jennifer L

    2015-06-01

    The process of leaving an abusive partner has been theorized using the Stages of Change Model. Although useful, this model does not account for changes in relational boundaries unique to the process of leaving. Using family stress and feminist perspectives, this study sought to integrate boundary ambiguity into the Stages of Change Model. Boundary ambiguity is defined as a perception of uncertainty as to who is in or out of a family system (Boss & Greenberg, 1984). Twenty-five mothers who had temporarily or permanently left their abusers were interviewed. Data were analyzed using constructivist grounded theory methods. Results identify types, indicators of, and mothers' responses to boundary ambiguity throughout the five stages of change. Most mothers and abusers fluctuated between physical and psychological presence and absence over multiple separations. The integration of boundary ambiguity into the Stages of Change Model highlights the process of leaving an abusive partner as systemic, fluid, and nonlinear.

  7. Perceptions of boundary ambiguity in the process of leaving an abusive partner.

    PubMed

    Khaw, Lyndal; Hardesty, Jennifer L

    2015-06-01

    The process of leaving an abusive partner has been theorized using the Stages of Change Model. Although useful, this model does not account for changes in relational boundaries unique to the process of leaving. Using family stress and feminist perspectives, this study sought to integrate boundary ambiguity into the Stages of Change Model. Boundary ambiguity is defined as a perception of uncertainty as to who is in or out of a family system (Boss & Greenberg, 1984). Twenty-five mothers who had temporarily or permanently left their abusers were interviewed. Data were analyzed using constructivist grounded theory methods. Results identify types, indicators of, and mothers' responses to boundary ambiguity throughout the five stages of change. Most mothers and abusers fluctuated between physical and psychological presence and absence over multiple separations. The integration of boundary ambiguity into the Stages of Change Model highlights the process of leaving an abusive partner as systemic, fluid, and nonlinear. PMID:25286330

  8. Planned Giving for Catholic Schools.

    ERIC Educational Resources Information Center

    Bourbeau, Mary Ann

    Good development officers in elementary and high schools need to be aware of planned giving and knowledgeable about a variety of gift categories. Most school-development directors are not experts in this complex field. Yet, when a school decides to initiate a planned-giving program, the director of development must make a serious commitment to…

  9. Steps in the Child's Grasp of Ambiguities through Word Play.

    ERIC Educational Resources Information Center

    Geller, Linda Gibson

    A study examined the differences in the appreciation of language ambiguity as represented in the word play of children aged 6 through 11 years. In six weekly play sessions, students were read stories containing many lexical ambiguities and pictures and were invited to verbalize and to draw similar ambiguities. Criteria necessary to the…

  10. Disambiguation of ambiguous figures in the brain

    PubMed Central

    Ishizu, Tomohiro

    2013-01-01

    Disambiguation refers to the ability to interpret ambiguous information in a sensible way, which is important in an ever-changing external environment. Disambiguation occurs when prior knowledge is given before an ambiguous stimulus is presented. For example, labeling a series of meaningless blobs as a “human body” can change the observer's perception. The aim of this experiment was to study the neural circuitry underlying disambiguation caused by prior knowledge. We presented to participants a series of meaningless blobs with different contextual information. As participants performed this task, we used magnetoencephalography to map the brain areas that were activated when participants perceived blobs as a human body. The participants were presented identical sets of blob stimuli, and were instructed that a human body would appear more frequently in the “high body” condition than in the “low body” condition. We found the blob stimuli were more frequently perceived as the human body when they were presented in the “high body” condition. Such contextual modulation correlated with activity in the extrastriate body area (EBA) and the inferior frontal gyrus (IFG). Furthermore, we observed that IFG activation preceded EBA activation. These findings suggest that top-down processing in the IFG plays a role in disambiguating ambiguous information and modifying an individual's perceptions. PMID:24009570

  11. Human Perception of Ambiguous Inertial Motion Cues

    NASA Technical Reports Server (NTRS)

    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

  12. Ionosphere influence on success rate of GPS ambiguity resolution in a satellite formation flying

    NASA Astrophysics Data System (ADS)

    Baroni, Leandro

    2015-10-01

    Satellite formation flying is one of the most promising technologies for future space missions. The distribution of sensors and payloads among different satellites provides more redundancy, flexibility, improved communication coverage, among other advantages. One of the fundamental issues in spacecraft formation flying is precise position and velocity determination between satellites. For missions in low Earth orbits, GPS system can meet the precision requirement in relative positioning, since the satellite dynamics is modeled properly. The key for high accuracy GPS relative positioning is to resolve the ambiguities to their integer values. Ambiguities resolved successfully can improve the positioning accuracy to decimetre or even millimetre-level. So, integer carrier phase ambiguity resolution is often a prerequisite for high precision GPS positioning. The determination of relative position was made using an extended Kalman filter. The filter must take into account imperfections in dynamic modeling of perturbations affecting the orbital flight, and changes in solar activity that affects the GPS signal propagation, for mitigating these effects on relative positioning accuracy. Thus, this work aims to evaluate the impact of ionosphere variation, caused by changes in solar activity, in success rate of ambiguity resolution. Using the Ambiguity Dilution of Precision (ADOP) concept, the ambiguity success rate is analyzed and the expected precision of the ambiguity-fixed solution is calculated. Evaluations were performed using actual data from GRACE mission and analyzed for their performance in real scenarios. Analyses were conducted in different configurations of relative position and during different levels of solar activity. Results bring the impact of various disturbances and modeling of solar activity level on the success rate of ambiguity resolution.

  13. The inertial attitude augmentation for ambiguity resolution in SF/SE-GNSS attitude determination.

    PubMed

    Zhu, Jiancheng; Hu, Xiaoping; Zhang, Jingyu; Li, Tao; Wang, Jinling; Wu, Meiping

    2014-06-26

    The Unaided Single Frequency/Single Epoch Global Navigation Satellite System (SF/SE GNSS) model is the most challenging scenario for ambiguity resolution in the GNSS attitude determination application. To improve the performance of SF/SE-GNSS ambiguity resolution without excessive cost, the Micro-Electro-Mechanical System Inertial Measurement Unit (MEMS-IMU) is a proper choice for the auxiliary sensor that carries out the inertial attitude augmentation. Firstly, based on the SF/SE-GNSS compass model, the Inertial Derived Baseline Vector (IDBV) is defined to connect the MEMS-IMU attitude measurement with the SF/SE-GNSS ambiguity search space, and the mechanism of inertial attitude augmentation is revealed from the perspective of geometry. Then, through the quantitative description of model strength by Ambiguity Dilution of Precision (ADOP), two ADOPs are specified for the unaided SF/SE-GNSS compass model and its inertial attitude augmentation counterparts, respectively, and a sufficient condition is proposed for augmenting the SF/SE-GNSS model strength with inertial attitude measurement. Finally, in the framework of an integer aperture estimator with fixed failure rate, the performance of SF/SE-GNSS ambiguity resolution with inertial attitude augmentation is analyzed when the model strength is varying from strong to weak. The simulation results show that, in the SF/SE-GNSS attitude determination application, MEMS-IMU can satisfy the requirements of ambiguity resolution with inertial attitude augmentation.

  14. The Inertial Attitude Augmentation for Ambiguity Resolution in SF/SE-GNSS Attitude Determination

    PubMed Central

    Zhu, Jiancheng; Hu, Xiaoping; Zhang, Jingyu; Li, Tao; Wang, Jinling; Wu, Meiping

    2014-01-01

    The Unaided Single Frequency/Single Epoch Global Navigation Satellite System (SF/SE GNSS) model is the most challenging scenario for ambiguity resolution in the GNSS attitude determination application. To improve the performance of SF/SE-GNSS ambiguity resolution without excessive cost, the Micro-Electro-Mechanical System Inertial Measurement Unit (MEMS-IMU) is a proper choice for the auxiliary sensor that carries out the inertial attitude augmentation. Firstly, based on the SF/SE-GNSS compass model, the Inertial Derived Baseline Vector (IDBV) is defined to connect the MEMS-IMU attitude measurement with the SF/SE-GNSS ambiguity search space, and the mechanism of inertial attitude augmentation is revealed from the perspective of geometry. Then, through the quantitative description of model strength by Ambiguity Dilution of Precision (ADOP), two ADOPs are specified for the unaided SF/SE-GNSS compass model and its inertial attitude augmentation counterparts, respectively, and a sufficient condition is proposed for augmenting the SF/SE-GNSS model strength with inertial attitude measurement. Finally, in the framework of an integer aperture estimator with fixed failure rate, the performance of SF/SE-GNSS ambiguity resolution with inertial attitude augmentation is analyzed when the model strength is varying from strong to weak. The simulation results show that, in the SF/SE-GNSS attitude determination application, MEMS-IMU can satisfy the requirements of ambiguity resolution with inertial attitude augmentation. PMID:24971472

  15. A study of potential sources of linguistic ambiguity in written work instructions.

    SciTech Connect

    Matzen, Laura E.

    2009-11-01

    This report describes the results of a small experimental study that investigated potential sources of ambiguity in written work instructions (WIs). The English language can be highly ambiguous because words with different meanings can share the same spelling. Previous studies in the nuclear weapons complex have shown that ambiguous WIs can lead to human error, which is a major cause for concern. To study possible sources of ambiguity in WIs, we determined which of the recommended action verbs in the DOE and BWXT writer's manuals have numerous meanings to their intended audience, making them potentially ambiguous. We used cognitive psychology techniques to conduct a survey in which technicians who use WIs in their jobs indicated the first meaning that came to mind for each of the words. Although the findings of this study are limited by the small number of respondents, we identified words that had many different meanings even within this limited sample. WI writers should pay particular attention to these words and to their most frequent meanings so that they can avoid ambiguity in their writing.

  16. Athletes' perceptions of role ambiguity and coaching competency in sport teams: a multilevel analysis.

    PubMed

    Bosselut, Grégoire; Heuzé, Jean-Philippe; Eys, Mark A; Fontayne, Paul; Sarrazin, Philippe

    2012-06-01

    The purpose of this study was to examine the relationship between athletes' perceptions of role ambiguity and two theoretically derived dimensions of coaching competency (i.e., game strategy and technique competencies). A total of 243 players from 26 teams representing various interdependent sports completed French versions of the Role Ambiguity Scale and the Coaching Competency Scale. Multilevel analyses supported the existence of relationships between the four dimensions of role ambiguity and the two dimensions of coaching competency at both individual and team levels. When the levels were considered jointly, athletes perceiving greater ambiguity in their role in both offensive and defensive contexts were more critical of their coach's capacities to lead their team during competitions and to diagnose or formulate instructions during training sessions. The results also indicated that the dimension of scope of responsibilities was the main contributor to the relationship with coaching competency at an individual level, whereas role evaluation was the main contributor to this relationship at a group level. Findings are discussed in relation to the role episode model, the role ambiguity dimensions involved in the relationships according to the level of analysis considered, and the salience of ambiguity perceptions in the offensive context.

  17. Decoding covert shifts of attention induced by ambiguous visuospatial cues

    PubMed Central

    Trachel, Romain E.; Clerc, Maureen; Brochier, Thomas G.

    2015-01-01

    Simple and unambiguous visual cues (e.g., an arrow) can be used to trigger covert shifts of visual attention away from the center of gaze. The processing of visual stimuli is enhanced at the attended location. Covert shifts of attention modulate the power of cerebral oscillations in the alpha band over parietal and occipital regions. These modulations are sufficiently robust to be decoded on a single trial basis from electroencephalography (EEG) signals. It is often assumed that covert attention shifts are under voluntary control, and that they also occur in more natural and complex environments, but there is no direct evidence to support this assumption. We address this important issue by using random-dot stimuli to cue one of two opposite locations, where a visual target is presented. We contrast two conditions, one in which the random-dot motion is predictive of the target location, and the other, in which it provides ambiguous information. Behavioral results show attention shifts in anticipation of the visual target, in both conditions. In addition, using the common spatial patterns (CSPs) algorithm, we extract EEG power features in the alpha-band (around 10 Hz) that best discriminate the attended location in single trials. We obtain a significant decoding accuracy in 7/10 subjects using a cross-validation procedure applied in the predictive condition. Interestingly, similar accuracy (significant in 5/10 subjects) is obtained when the CSPs trained in the predictive condition are tested in the ambiguous condition. In agreement with this result, we find that the CSPs show very similar topographies in both conditions. These results shed a new light on the behavioral and EEG correlates of visuospatial attention in complex visual environments. This study demonstrates that alpha-power features could be used in brain–computer interfaces to decode covert attention shifts in an environment containing ambiguous spatial information. PMID:26150780

  18. Resolving the sign ambiguity in the singular value decomposition.

    SciTech Connect

    Bro, Rasmus; Acar, Evrim; Kolda, Tamara Gibson

    2007-10-01

    Many modern data analysis methods involve computing a matrix singular value decomposition (SVD) or eigenvalue decomposition (EVD). Principal components analysis is the time-honored example, but more recent applications include latent semantic indexing, hypertext induced topic selection (HITS), clustering, classification, etc. Though the SVD and EVD are well-established and can be computed via state-of-the-art algorithms, it is not commonly mentioned that there is an intrinsic sign indeterminacy that can significantly impact the conclusions and interpretations drawn from their results. Here we provide a solution to the sign ambiguity problem and show how it leads to more sensible solutions.

  19. Simply Imagining Sunshine, Lollipops and Rainbows Will Not Budge the Bias: The Role of Ambiguity in Interpretive Bias Modification.

    PubMed

    Clarke, Patrick J F; Nanthakumar, Shenooka; Notebaert, Lies; Holmes, Emily A; Blackwell, Simon E; Macleod, Colin

    2014-01-01

    Imagery-based interpretive bias modification (CBM-I) involves repeatedly imagining scenarios that are initially ambiguous before being resolved as either positive or negative in the last word/s. While the presence of such ambiguity is assumed to be important to achieve change in selective interpretation, it is also possible that the act of repeatedly imagining positive or negative events could produce such change in the absence of ambiguity. The present study sought to examine whether the ambiguity in imagery-based CBM-I is necessary to elicit change in interpretive bias, or, if the emotional content of the imagined scenarios is sufficient to produce such change. An imagery-based CBM-I task was delivered to participants in one of four conditions, where the valence of imagined scenarios were either positive or negative, and the ambiguity of the scenario was either present (until the last word/s) or the ambiguity was absent (emotional valence was evident from the start). Results indicate that only those who received scenarios in which the ambiguity was present acquired an interpretive bias consistent with the emotional valence of the scenarios, suggesting that the act of imagining positive or negative events will only influence patterns of interpretation when the emotional ambiguity is a consistent feature. PMID:24634553

  20. Ambiguity and synonymy effects in lexical decision, naming, and semantic categorization tasks: interactions between orthography, phonology, and semantics.

    PubMed

    Hino, Yasushi; Lupker, Stephen J; Pexman, Penny M

    2002-07-01

    In this article, ambiguity and synonymy effects were examined in lexical decision, naming, and semantic categorization tasks. Whereas the typical ambiguity advantage was observed in lexical decision and naming, an ambiguity disadvantage was observed in semantic categorization. In addition, a synonymy effect (slower latencies for words with many synonyms than for words with few synonyms) was observed in lexical decision and naming but not in semantic categorization. These results suggest that (a) an ambiguity disadvantage arises only when a task requires semantic processing, (b) the ambiguity advantage and the synonymy disadvantage in lexical decision and naming are due to semantic feedback, and (c) these effects are determined by the nature of the feedback relationships from semantics to orthography and phonology.

  1. Infants interpret ambiguous requests for absent objects.

    PubMed

    Saylor, Megan M; Ganea, Patricia

    2007-05-01

    The current studies investigated 2 skills involved in 14- to 20- month-olds' ability to interpret ambiguous requests for absent objects: tracking others' experiences (Study 1) and representing links between speakers and object features across present and absent reference episodes (Study 2). In the basic task, 2 experimenters played separately with a different ball. The balls were placed in opaque containers. One experimenter asked infants to retrieve her ball using an ambiguous request ("Where's the ball?"). In Study 1, infants used the experimenter's prior verbal and physical contact with the ball to interpret the request. A control condition demonstrated that infants were interpreting the request and not responding to the mere presence of the experimenter. Study 2 revealed that only infants who were given stable cues to the ball's spatial location appropriately interpreted the request: When spatial information was put in conflict with a color cue, infants did not select the correct ball. Links to infants' spatial memory skills and emerging pragmatic understanding are discussed. PMID:17484581

  2. Ambiguous idiom processing in Parkinson's disease patients.

    PubMed

    Papagno, Costanza; Mattavelli, Giulia; Cattaneo, Zaira; Romito, Luigi; Albanese, Alberto

    2013-01-01

    Patients affected by Parkinson's disease (PD) can provide crucial information about the involvement of the motor system and prefrontal cortex in processing idioms including action verbs, since dopamine modulates the activity of these structures, and, consequently, different levels of this neurotransmitter can induce different cognitive impairments. In order to investigate the ability to process ambiguous idioms containing an action verb in patients, we asked 15 PD patients, in both OFF- and ON-phases, and 15 healthy matched participants to judge the plausibility of literal and idiomatic sentences, each presented at a self-paced rate. Patients in OFF-phase were faster in reading idiomatic than literal sentences, supporting the view that the motor system is not involved in online idiom processing. However, patients during OFF-phase were impaired in judging the plausibility of idiomatic ambiguous sentences, possibly due to the reduction of dopamine in prefrontal regions. The involvement of the motor system was evident in the ON-phase for literal sentences, suggesting that motor activation is strictly dependent on the context. PMID:24479736

  3. The ambiguous nature of epigenetic responsibility.

    PubMed

    Dupras, Charles; Ravitsky, Vardit

    2016-08-01

    Over the past decade, epigenetic studies have been providing further evidence of the molecular interplay between gene expression and its health outcomes on one hand, and the physical and social environments in which individuals are conceived, born and live on the other. As knowledge of epigenetic programming expands, a growing body of literature in social sciences and humanities is exploring the implications of this new field of study for contemporary societies. Epigenetics has been mobilised to support political claims, for instance, with regard to collective obligations to address socio-environmental determinants of health. The idea of a moral 'epigenetic responsibility' has been proposed, meaning that individuals and/or governments should be accountable for the epigenetic programming of children and/or citizens. However, these discussions have largely overlooked important biological nuances and ambiguities inherent in the field of epigenetics. In this paper, we argue that the identification and assignment of moral epigenetic responsibilities should reflect the rich diversity and complexity of epigenetic mechanisms, and not rely solely on a gross comparison between epigenetics and genetics. More specifically, we explore how further investigation of the ambiguous notions of epigenetic normality and epigenetic plasticity should play a role in shaping this emerging debate. PMID:27015741

  4. Improving Ambiguity Resolution for Medium Baselines Using Combined GPS and BDS Dual/Triple-Frequency Observations.

    PubMed

    Gao, Wang; Gao, Chengfa; Pan, Shuguo; Wang, Denghui; Deng, Jiadong

    2015-10-30

    The regional constellation of the BeiDou navigation satellite system (BDS) has been providing continuous positioning, navigation and timing services since 27 December 2012, covering China and the surrounding area. Real-time kinematic (RTK) positioning with combined BDS and GPS observations is feasible. Besides, all satellites of BDS can transmit triple-frequency signals. Using the advantages of multi-pseudorange and carrier observations from multi-systems and multi-frequencies is expected to be of much benefit for ambiguity resolution (AR). We propose an integrated AR strategy for medium baselines by using the combined GPS and BDS dual/triple-frequency observations. In the method, firstly the extra-wide-lane (EWL) ambiguities of triple-frequency system, i.e., BDS, are determined first. Then the dual-frequency WL ambiguities of BDS and GPS were resolved with the geometry-based model by using the BDS ambiguity-fixed EWL observations. After that, basic (i.e., L1/L2 or B1/B2) ambiguities of BDS and GPS are estimated together with the so-called ionosphere-constrained model, where the ambiguity-fixed WL observations are added to enhance the model strength. During both of the WL and basic AR, a partial ambiguity fixing (PAF) strategy is adopted to weaken the negative influence of new-rising or low-elevation satellites. Experiments were conducted and presented, in which the GPS/BDS dual/triple-frequency data were collected in Nanjing and Zhengzhou of China, with the baseline distance varying from about 28.6 to 51.9 km. The results indicate that, compared to the single triple-frequency BDS system, the combined system can significantly enhance the AR model strength, and thus improve AR performance for medium baselines with a 75.7% reduction of initialization time on average. Besides, more accurate and stable positioning results can also be derived by using the combined GPS/BDS system.

  5. The New Planned Giving Officer.

    ERIC Educational Resources Information Center

    Jordan, Ronald R.; Quynn, Katelyn L.

    1994-01-01

    A planned giving officer is seen as an asset to college/university development for technical expertise, credibility, and connections. Attorneys, certified public accountants, bank trust officers, financial planners, investment advisers, life insurance agents, and real estate brokers may be qualified but probably also need training. (MSE)

  6. Giving Psychology Away Is Expensive

    ERIC Educational Resources Information Center

    Gorsuch, Richard L.; Wallace, William L.

    2005-01-01

    This article presents comments on "Does Psychology make a significant difference in our lives?" by P. Zimbardo. We deeply appreciate the documentation and inspiration provided by Zimbardo on how psychology is reaching out to the public by "giving psychology away" (p. 340). We totally agree that psychology has much, much more to offer that could be…

  7. The New Planned Giving Landscape.

    ERIC Educational Resources Information Center

    Moerschbaecher, Lynda

    1987-01-01

    The best way to support charitable causes after tax reform is planned giving. Seven changes in the new tax laws that may affect donors are identified: charitable deduction, fewer deductions, fewer itemizers, increased capital gains tax, alternative minimum tax, generation-skipping tax, and retirement plan restrictions. (MLW)

  8. Ambiguity between self and other: Individual differences in action attribution.

    PubMed

    de Bézenac, Christophe E; Sluming, Vanessa; O'Sullivan, Noreen; Corcoran, Rhiannon

    2015-09-01

    Individuals differ in their ability to attribute actions to self or other. This variance is thought to explain, in part, the experience of voice-hearing. Misattribution can also be context-driven. For example, causal ambiguity can arise when the actions of two or more individuals are coordinated and produce similar effects (e.g., music-making). Experience in such challenging contexts may refine skills of action attribution. Forty participants completed a novel finger-tapping task which parametrically manipulated the proportion of control that 'self' versus 'other' possessed over resulting auditory tones. Results showed that action misattribution peaked in the middle of the self-to-other continuum and was biased towards other. This pattern was related to both high hallucination-proneness and to low musical-experience. Findings suggest not only that causal ambiguity plays a key role in agency but also that action attribution abilities may improve with practice, potentially providing an avenue for remediation of the positive symptoms of schizophrenia. PMID:25956971

  9. Effects of pitch accents in attachment ambiguity resolution

    PubMed Central

    Lee, Eun-Kyung; Watson, Duane G.

    2011-01-01

    Previous work has found that listeners prefer to attach ambiguous syntactic constituents to nouns produced with a pitch accent (Schafer et al., 1996). This study examines what factors underlie previously established accent attachment effects by testing whether these effects are driven by a preference to attach syntactic constituents to new or important information (the Syntax Hypothesis) or whether there is a bias to respond to post-sentence probe questions with an accented word (the Salience Hypothesis). One of the predictions of the Salience Hypothesis is that selection of accented words should be greater when a sentence is complex and processing resources are limited. The results from the experiments presented here show that the probability of listeners’ selecting accented words when asked about the interpretation of a relative clause varies with sentence type: listeners selected accented words more frequently in long sentences than in short sentences, consistent with the predictions of the Salience Hypothesis. Furthermore, Experiment 4 demonstrates that listeners are more likely to respond to post-sentence questions with accented words than with non-accented words, even when no ambiguity is present, and even when the response results in an incorrect answer. These findings suggest that accent-driven attachment effects found in earlier studies reflect a post-sentence selection process rather than a syntactic processing mechanism. PMID:22287815

  10. Ambiguity between self and other: Individual differences in action attribution.

    PubMed

    de Bézenac, Christophe E; Sluming, Vanessa; O'Sullivan, Noreen; Corcoran, Rhiannon

    2015-09-01

    Individuals differ in their ability to attribute actions to self or other. This variance is thought to explain, in part, the experience of voice-hearing. Misattribution can also be context-driven. For example, causal ambiguity can arise when the actions of two or more individuals are coordinated and produce similar effects (e.g., music-making). Experience in such challenging contexts may refine skills of action attribution. Forty participants completed a novel finger-tapping task which parametrically manipulated the proportion of control that 'self' versus 'other' possessed over resulting auditory tones. Results showed that action misattribution peaked in the middle of the self-to-other continuum and was biased towards other. This pattern was related to both high hallucination-proneness and to low musical-experience. Findings suggest not only that causal ambiguity plays a key role in agency but also that action attribution abilities may improve with practice, potentially providing an avenue for remediation of the positive symptoms of schizophrenia.

  11. Sensorimotor Adaptation Following Exposure to Ambiguous Inertial Motion Cues

    NASA Technical Reports Server (NTRS)

    Wood, S. J.; Clement, G. R.; Harm, D L.; Rupert, A. H.; Guedry, F. E.; Reschke, M. F.

    2005-01-01

    The central nervous system must resolve the ambiguity of inertial motion sensory cues in order to derive accurate spatial orientation awareness. Our general hypothesis is that the central nervous system utilizes both multi-sensory integration and frequency segregation as neural strategies to resolve the ambiguity of tilt and translation stimuli. Movement in an altered gravity environment, such as weightlessness without a stable gravity reference, results in new patterns of sensory cues. For example, the semicircular canals, vision and neck proprioception provide information about head tilt on orbit without the normal otolith head-tilt position that is omnipresent on Earth. 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 disorientation and tilt-translation disturbances reported by crewmembers 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.

  12. Sensorimotor Adaptation Following Exposure to Ambiguous Inertial Motion Cues

    NASA Technical Reports Server (NTRS)

    Wood, S. J.; Clement, G. R.; Harm, D. L.; Rupert, A. H.; Guedry, F. E.; Reschke, M. F.

    2005-01-01

    The central nervous system must resolve the ambiguity of inertial motion sensory cues in order to derive accurate spatial orientation awareness. Our general hypothesis is that the central nervous system utilizes both multi-sensory integration and frequency segregation as neural strategies to resolve the ambiguity of tilt and translation stimuli. Movement in an altered gravity environment, such as weightlessness without a stable gravity reference, results in new patterns of sensory cues. For example, the semicircular canals, vision and neck proprioception provide information about head tilt on orbit without the normal otolith head-tilt position that is omnipresent on Earth. 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 disorientation and tilt-translation disturbances reported by crewmembers 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.

  13. Lexical and Prosodic Effects on Syntactic Ambiguity Resolution in Aphasia

    PubMed Central

    DeDe, Gayle

    2012-01-01

    The purpose of this study was to determine whether and when individuals with aphasia and healthy controls use lexical and prosodic information during on-line sentence comprehension. Individuals with aphasia and controls (n = 12 per group) participated in a self-paced listening experiment. The stimuli were early closure sentences, such as “While the parents watched(,) the child sang a song.” Both lexical and prosodic cues were manipulated. The cues were biased toward the subject- or object- of the ambiguous noun phrase (the child). Thus, there were two congruous conditions (in which both lexical cues and prosodic cues were consistent) and two incongruous conditions (in which lexical and prosodic cues conflicted). The results showed that the people with aphasia had longer listening times for the ambiguous noun phrase (the child) when the cues were conflicting, rather than consistent. The controls showed effects earlier in the sentence, at the subordinate verb (watched or danced). Both groups showed evidence of reanalysis at the main verb (sang). These effects demonstrate that the aphasic group was sensitive to the lexical and prosodic cues, but used them on a delayed time course relative to the control group. PMID:22143353

  14. Ambiguous science and the visual representation of the real

    NASA Astrophysics Data System (ADS)

    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.

  15. How ambiguous is the local kinetic energy?

    PubMed

    Anderson, James S M; Ayers, Paul W; Hernandez, Juan I Rodriguez

    2010-08-26

    The local kinetic energy and the closely related local electronic stress tensor are commonly used to elucidate chemical bonding patterns, especially for covalent bonds. We use three different approaches-transformation properties of the stress tensor, quasiprobability distributions, and the virial theorem from density-functional theory-to clarify the inherent ambiguity in these quantities, discussing the implications for analyses based on the local kinetic energy and stress tensor. An expansive-but not universal-family of local kinetic energy forms that includes the most common choices and is suitable for both chemical-bonding and atoms-in-molecule analysis is derived. A family of local electronic stress tensors is also derived. Several local kinetic energy functions that are mathematically justified, but unlikely to be conceptually useful, are derived. The implications of these forms for atoms-in-molecule analysis are discussed.

  16. How ambiguous is the local kinetic energy?

    PubMed

    Anderson, James S M; Ayers, Paul W; Hernandez, Juan I Rodriguez

    2010-08-26

    The local kinetic energy and the closely related local electronic stress tensor are commonly used to elucidate chemical bonding patterns, especially for covalent bonds. We use three different approaches-transformation properties of the stress tensor, quasiprobability distributions, and the virial theorem from density-functional theory-to clarify the inherent ambiguity in these quantities, discussing the implications for analyses based on the local kinetic energy and stress tensor. An expansive-but not universal-family of local kinetic energy forms that includes the most common choices and is suitable for both chemical-bonding and atoms-in-molecule analysis is derived. A family of local electronic stress tensors is also derived. Several local kinetic energy functions that are mathematically justified, but unlikely to be conceptually useful, are derived. The implications of these forms for atoms-in-molecule analysis are discussed. PMID:20586467

  17. Dealing with the Ambiguities of Science Inquiry

    NASA Astrophysics Data System (ADS)

    Tan, Yuen Sze Michelle; Caleon, Imelda Santos

    2016-03-01

    The current vision of science education in myriad educational contexts encourages students to learn through the process of science inquiry. Science inquiry has been used to promote conceptual learning and engage learners in an active process of meaning-making and investigation to understand the world around them. The science inquiry process typically involves asking questions and defining problems; constructing explanations and designing solutions; planning and carrying out investigations; analyzing and interpreting data; and engaging in argument from evidence. Despite the importance and provision of new directions and standards about science inquiry, ambiguities in conceptualizations of inquiry still exist. These conceptualizations may serve as barriers to students learning science. In this article, we detail three main concerns related to teachers' conceptualization of science inquiry in the context of a Singapore classroom—concerns that may be similarly faced by teachers elsewhere.

  18. Ambiguity resolution for satellite Doppler positioning systems

    NASA Technical Reports Server (NTRS)

    Argentiero, P. D.; Marini, J. W.

    1977-01-01

    A test for ambiguity resolution was derived which was the most powerful in the sense that it maximized the probability of a correct decision. When systematic error sources were properly included in the least squares reduction process to yield an optimal solution, the test reduced to choosing the solution which provided the smaller valuation of the least squares loss function. When systematic error sources were ignored in the least squares reduction, the most powerful test was a quadratic form comparison with the weighting matrix of the quadratic form obtained by computing the pseudo-inverse of a reduced rank square matrix. A formula is presented for computing the power of the most powerful test. A numerical example is included in which the power of the test is computed for a situation which may occur during an actual satellite aided search and rescue mission.

  19. Coordinate parameters eliminated and stepwise ambiguities resolution method for mid-long baseline

    NASA Astrophysics Data System (ADS)

    Tang, Weiming; Liu, Jingnan; Shi, Chuang

    2008-12-01

    The high precision relative positioning is one of the key conditions of multiple earth-observation satellites differential observation. Usually, the earth-observation satellites' relative positions are got by GNSS differential positioning. The key technology of GNSS high precision differential positioning is carrier phase AR (Ambiguity Resolution). The distance between two earth-observation satellites is from several kilometers to several hundreds kilometers. So it's a problem of ambiguities resolution for mid-long distance baseline. There are a lot of difficulties to solve this kind of ambiguities such as large double difference systematic errors. In order to solve these difficulties, this paper proposed a fast and kinematic AR method named as CPES (Coordinate Parameters Eliminated and Stepwise) method which is based on LAMBDA method. At first, the primary theories of this method are introduced. Then, the steps from wide-lane ambiguities resolution to L1, L2 ambiguities resolution are proposed. Lastly, several examples' results show that this AR method has the advantages of fast speed and high reliability.

  20. Essentialist thinking predicts decrements in children's memory for racially ambiguous faces.

    PubMed

    Gaither, Sarah E; Schultz, Jennifer R; Pauker, Kristin; Sommers, Samuel R; Maddox, Keith B; Ambady, Nalini

    2014-02-01

    Past research shows that adults often display poor memory for racially ambiguous and racial outgroup faces, with both face types remembered worse than own-race faces. In the present study, the authors examined whether children also show this pattern of results. They also examined whether emerging essentialist thinking about race predicts children's memory for faces. Seventy-four White children (ages 4-9 years) completed a face-memory task comprising White, Black, and racially ambiguous Black-White faces. Essentialist thinking about race was also assessed (i.e., thinking of race as immutable and biologically based). White children who used essentialist thinking showed the same bias as White adults: They remembered White faces significantly better than they remembered ambiguous and Black faces. However, children who did not use essentialist thinking remembered both White and racially ambiguous faces significantly better than they remembered Black faces. This finding suggests a specific shift in racial thinking wherein the boundaries between racial groups become more discrete, highlighting the importance of how race is conceptualized in judgments of racially ambiguous individuals.

  1. Making Decisions under Ambiguity: Judgment Bias Tasks for Assessing Emotional State in Animals.

    PubMed

    Roelofs, Sanne; Boleij, Hetty; Nordquist, Rebecca E; van der Staay, Franz Josef

    2016-01-01

    Judgment bias tasks (JBTs) are considered as a family of promising tools in the assessment of emotional states of animals. JBTs provide a cognitive measure of optimism and/or pessimism by recording behavioral responses to ambiguous stimuli. For instance, a negative emotional state is expected to produce a negative or pessimistic judgment of an ambiguous stimulus, whereas a positive emotional state produces a positive or optimistic judgment of the same ambiguous stimulus. Measuring an animal's emotional state or mood is relevant in both animal welfare research and biomedical research. This is reflected in the increasing use of JBTs in both research areas. We discuss the different implementations of JBTs with animals, with a focus on their potential as an accurate measure of emotional state. JBTs have been successfully applied to a very broad range of species, using many different types of testing equipment and experimental protocols. However, further validation of this test is deemed necessary. For example, the often extensive training period required for successful judgment bias testing remains a possible factor confounding results. Also, the issue of ambiguous stimuli losing their ambiguity with repeated testing requires additional attention. Possible improvements are suggested to further develop the JBTs in both animal welfare and biomedical research. PMID:27375454

  2. Making Decisions under Ambiguity: Judgment Bias Tasks for Assessing Emotional State in Animals

    PubMed Central

    Roelofs, Sanne; Boleij, Hetty; Nordquist, Rebecca E.; van der Staay, Franz Josef

    2016-01-01

    Judgment bias tasks (JBTs) are considered as a family of promising tools in the assessment of emotional states of animals. JBTs provide a cognitive measure of optimism and/or pessimism by recording behavioral responses to ambiguous stimuli. For instance, a negative emotional state is expected to produce a negative or pessimistic judgment of an ambiguous stimulus, whereas a positive emotional state produces a positive or optimistic judgment of the same ambiguous stimulus. Measuring an animal’s emotional state or mood is relevant in both animal welfare research and biomedical research. This is reflected in the increasing use of JBTs in both research areas. We discuss the different implementations of JBTs with animals, with a focus on their potential as an accurate measure of emotional state. JBTs have been successfully applied to a very broad range of species, using many different types of testing equipment and experimental protocols. However, further validation of this test is deemed necessary. For example, the often extensive training period required for successful judgment bias testing remains a possible factor confounding results. Also, the issue of ambiguous stimuli losing their ambiguity with repeated testing requires additional attention. Possible improvements are suggested to further develop the JBTs in both animal welfare and biomedical research. PMID:27375454

  3. Resolution of Ambiguous HLA Genotyping in Korean by Multi-Group-Specific Sequence-Based Typing

    PubMed Central

    Park, Yongjung; Yoon, Cha Eun; Kwon, Oh-Joong; Kim, Yu-Seun

    2014-01-01

    Purpose To evaluate a multi-group-specific sequence-based typing (SBT) method for resolving ambiguous results from human leukocyte antigen (HLA) genotyping. Materials and Methods A total of 50 samples that showed ambiguous genotypes for at least two HLA loci from HLA-A, -B, -C and -DRB1 by the conventional SBT assay were evaluated using a new SBT test, the AVITA plus assay. The most likely HLA genotypes for the respective samples considering allele frequencies in Korean were concordant between the AVITA and conventional SBT assays. Results An average of 3.3 loci among the HLA-A, -B, -C and -DRB1 loci per sample gave results with two or more possible allele combinations with the conventional SBT, and 48 (96.0%) out of 50 showed reduced numbers of possible genotypes for at least one HLA locus with the AVITA. A total of 41, 43, 42, and 38 cases among the 50 samples showed ambiguous results for HLA-A, -B, -C, and -DRB1 typing by the conventional SBT, respectively. The average numbers of possible allele combinations for the respective four HLA loci were 8.2, 6.7, 5.9, and 3.2, and they were reduced to 1.5, 2.2, 4.4, and 1.8, respectively, by the AVITA. Ambiguity was resolved by the AVITA in 33 (80.5%), 31 (72.1%), 17 (40.5%) and 28 (73.7%) samples among the ambiguous cases from the conventional SBT for HLA-A, -B, -C, and -DRB1 typing, respectively. Conclusion The multi-group-specific SBT method considerably reduced the number of ambiguous results, and thus may be useful for accurate HLA typing in clinical laboratories. PMID:24954331

  4. Competitive helping in online giving.

    PubMed

    Raihani, Nichola J; Smith, Sarah

    2015-05-01

    Unconditional generosity in humans is a puzzle. One possibility is that individuals benefit from being seen as generous if there is competition for access to partners and if generosity is a costly-and therefore reliable-signal of partner quality [1-3]. The "competitive helping" hypothesis predicts that people will compete to be the most generous, particularly in the presence of attractive potential partners [1]. However, this key prediction has not been directly tested. Using data from online fundraising pages, we demonstrate competitive helping in the real world. Donations to fundraising pages are public and made sequentially. Donors can therefore respond to the behavior of previous donors, creating a potential generosity tournament. Our test of the competitive helping hypothesis focuses on the response to large, visible donations. We show that male donors show significantly stronger responses (by donating more) when they are donating to an attractive female fundraiser and responding to a large donation made by another male donor. The responses for this condition are around four times greater than when males give to less-attractive female (or male) fundraisers or when they respond to a large donation made by a female donor. Unlike males, females do not compete in donations when giving to attractive male fundraisers. These data suggest that males use competitive helping displays in the presence of attractive females and suggest a role for sexual selection in explaining unconditional generosity.

  5. Giving a grand rounds presentation.

    PubMed

    Morrison, Laura J; Portenoy, Russell

    2010-12-01

    Giving a Grand Rounds presentation provides the hospice and palliative medicine subspecialist with the occasion to participate in a time-honored and respected event. It remains an opportunity to promote the discipline, support institutional culture change, and favorably influence the attitudes, knowledge, skills, and performance of colleagues. For those pursuing academic careers, it also is a chance to establish academic currency and develop teaching and presentation skills. In most academic settings, the format of Grand Rounds has shifted over time from a patient and problem-based discussion to a didactic, topic-focused lecture. A body of literature questions the value of this shift toward a more passive learner. Limited evidence prevents a definitive answer but many advocate for the integration of more interactive methods to improve the effectiveness of Grand Rounds. This article provides a flexible framework to guide those preparing to give a Grand Rounds and those teaching and supporting others to do so. To do this well, adult learning principles must be thoughtfully incorporated into a presentation style and method appropriate to the venue. The approach emphasizes learner-centeredness, interactive strategies, and evaluation. Room for creativity exists at every step and can add enjoyment and challenge along the way. PMID:21155643

  6. Ambiguities and Asymmetries in Consent and Refusal: Reply to Manson.

    PubMed

    Lawlor, Rob

    2016-06-01

    John Harris claims that is it 'palpable nonsense' to suggest that 'a child (or anyone) might competently consent to a treatment but not be competent to refuse it.' In 'Transitional Paternalism: How Shared Normative Powers Give Rise to the Asymmetry of Adolescent Consent and Refusal' Neil Manson aims to explain away the apparent oddness of this asymmetry of consent and refusal, by appealing to the idea of shared normative powers, presenting joint bank accounts as an example. In this article, I will argue that Manson's account fails to explain away the oddness. Rather, I will argue that there are ambiguities to which Manson has not paid sufficient attention. In fact, as odd as it may sound, I argue that Manson actually agrees with Harris (at least in relation to the asymmetry of competence). He fails to recognize that he agrees with Harris because he is not careful enough to distinguish between different asymmetries, which I have labelled the asymmetries of choice, permissibility and competence.

  7. Ethical assumptions and ambiguities in the Americans With Disabilities Act.

    PubMed

    Kopelman, L M

    1996-04-01

    The Americans With Disabilities Act (ADA) promotes social justice by protecting disabled persons from discrimination and prejudice. It seeks equality of opportunity for them and protects their well being by giving them fair access to goods, services and benefits. These rights are circumscribed in the ADA, however, by constraints of cost, efficiency, utility, and certain social mores. The ADA offers little direction about how to set priorities when these values come into conflict, or about whether equality or opportunity favors equivalent or preferential treatment for disadvantaged people. Until these ambiguities and potential value conflicts are resolved, a central moral and social problem remains unresolved: How can we demonstrate commitment to the rights and welfare of those with severe disabilities while placing fair limits upon their claims? Five special concerns are discussed: (1) eligibility and the allocation of health care; (2) the meaning of 'qualified but disabled' in employing people with mental disabilities; (3) equal opportunity and problems of envy and malingering; (4) ADA accommodation and public protection through testing and licensure; and (5) ADA protection and problems of backlash. Rather than simply wait to see what courts and administrative agencies decide, we should evaluate the moral conflicts, articulate criteria, and help make some difficult choices on morally defensible grounds.

  8. Trait ambiguity and impression formation sufficiency tests of the meaning change model.

    PubMed

    McKillip, J; Barrett, G; DiMiceli, A J

    1978-04-01

    Two experiments tested the meaning change model's prediction for the effect of trait ambiguity on impression formation. Participants were all college students, 43 males and 29 females in Experiment 1 and 20 males and 28 females in Experiment 2. Standard impression formation tasks were used. The results revealed greater context effects for high as compared to low ambiguous traits and greater influence on description ratings for low as compared to high ambigous traits, supporting the meaning change model. When ratings of descriptions and of individual traits were clearly separated, context effects were observed only for low ambiguous traits. The implications of this finding for meaning change and information integration models of impression formation are discussed PMID:660167

  9. Sexual Self-Concept Ambiguity and the Interpersonal Theory of Suicide Risk

    PubMed Central

    Talley, Amelia E.; Brown, Sarah L.; Cukrowicz, Kelly; Bagge, Courtney L.

    2015-01-01

    Mechanisms (i.e., thwarted belongingness, perceived burdensomeness, hopelessness) derived from the interpersonal theory of suicide which are hypothesized to account for the relation between sexual orientation self-concept ambiguity and active suicide ideation were examined. Participants included 349 women, among whom 42% currently self-ascribed a non-exclusively heterosexual sexual identity. Among women reporting higher levels of sexual self-concept ambiguity, greater risk for active suicide ideation is found when perceptions of burden and feelings of thwarted belonging co-occur with feelings of hopelessness. Results support relevant theory useful for understanding suicide risk among sexual minority women who acknowledge ambiguity with regard to their sexual orientation. PMID:26190166

  10. "Not one of us": predictors and consequences of denying ingroup characteristics to ambiguous targets.

    PubMed

    Kteily, Nour; Cotterill, Sarah; Sidanius, Jim; Sheehy-Skeffington, Jennifer; Bergh, Robin

    2014-10-01

    We investigated individual difference predictors of ascribing ingroup characteristics to negative and positive ambiguous targets. Studies 1 and 2 investigated events involving negative targets whose status as racial (Tsarnaev brothers) or national (Woolwich attackers) ingroup members remained ambiguous. Immediately following the attacks, we presented White Americans and British individuals with the suspects' images. Those higher in social dominance orientation (SDO) and right-wing authoritarianism (RWA)-concerned with enforcing status boundaries and adherence to ingroup norms, respectively-perceived these low status and low conformity suspects as looking less White and less British, thus denying them ingroup characteristics. Perceiving suspects in more exclusionary terms increased support for treating them harshly, and for militaristic counter-terrorism policies prioritizing ingroup safety over outgroup harm. Studies 3 and 4 experimentally manipulated a racially ambiguous target's status and conformity. Results suggested that target status and conformity critically influence SDO's (status) and RWA's (conformity) effects on inclusionary versus exclusionary perceptions.

  11. Is "Σ" purple or green? Bistable grapheme-color synesthesia induced by ambiguous characters.

    PubMed

    Kim, Suhkyung; Blake, Randolph; Kim, Chai-Youn

    2013-09-01

    People with grapheme-color synesthesia perceive specific colors when viewing different letters or numbers. Previous studies have suggested that synesthetic color experience can be bistable when induced by an ambiguous character. However, the exact relationship between processes underlying the identity of an alphanumeric character and the experience of the induced synesthetic color has not been examined. In the present study, we explored this by focusing on the temporal relation of inducer identification and color emergence using inducers whose identity could be rendered ambiguous upon rotation of the characters. Specifically, achromatic alphabetic letters (W/M) and digits (6/9) were presented at varying angles to 9 grapheme-color synesthetes. Results showed that grapheme identification and synesthetically perceived grapheme color covary with the orientation of the test stimulus and that synesthetes were slower naming the experienced color than identifying the character, particularly at intermediate angles where ambiguity was greatest.

  12. Anxiety and the interpretation of ambiguous information: beyond the emotion-congruent effect.

    PubMed

    Blanchette, Isabelle; Richards, Anne

    2003-06-01

    The authors investigated how anxiety influences the use of contextual information in the resolution of ambiguity. Participants heard ambiguous homophones (threat/neutral, positive/neural, and neutral/neutral) with related contextual information. State anxiety was manipulated experimentally. The interpretations of anxious participants were influenced by context to a greater extent than those of control participants. Some mood-incongruent effects were observed where anxious participants were more likely to adopt neutral interpretations of potentially threatening stimuli. Effects were observed in a spelling task (Experiments 1 and 2) and in a lexical decision task (Experiment 3), with supraliminal, and subliminal presentation of contextual cues, and with 2 different anxiety-induction procedures. Results show how anxiety affects both the content and the process of resolution of ambiguity.

  13. How Hispanic Patients Address Ambiguous versus Unambiguous Bias in the Doctor's Office

    PubMed Central

    Bean, Meghan G.; Covarrubias, Rebecca; Stone, Jeff

    2014-01-01

    Two studies examined Hispanic individuals’ preferences for using ten different bias reduction strategies when interacting with a doctor whose beliefs about their group were either ambiguous or clearly biased. Consistent with predictions, participants who imagined interacting with a doctor whose beliefs were ambiguous preferred strategies that facilitate positive doctor-patient interactions, whereas participants whose doctor explicitly endorsed negative stereotypes about their group preferred strategies that address stereotype content. The results also revealed that, regardless of whether the doctor's beliefs were ambiguous or clearly biased, stigma consciousness predicted participants’ preferences for using strategies that address stereotype content. These findings suggest that both doctors’ behavior and individual-level factors influence how minority individuals choose to behave in a healthcare setting. PMID:25395691

  14. Hey Little Sister, Who's the Only One? Modulating Informativeness in the Resolution of Privative Ambiguity.

    PubMed

    Foppolo, Francesca; Marelli, Marco; Meroni, Luisa; Gualmini, Andrea

    2015-09-01

    We present two eye-tracking experiments on the interpretation of sentences like "The tall girl is (not) the only one that …," which are ambiguous between the anaphoric (the only girl that …) and the exophoric interpretation (the only individual that …). These interpretations differ in informativeness: in a positive context, the exophoric (strong) reading entails the anaphoric (weak), while in a negative context the entailment pattern is reversed and the anaphoric reading is the strongest one. We tested whether adults rely on considerations about informativeness in solving the ambiguity. The results show that participants interpreted one exophorically in both positive and negative contexts. Given these findings, we cast doubts on the idea that Informativeness plays a role in ambiguity resolution and proposes a Principle of Maximal Exploitation: When a context is provided, adults extend their domain of evaluation to include the whole scenario, independently from truth-conditional considerations about informativity and strength.

  15. Competition during the processing of quantifier scope ambiguities: evidence from eye movements during reading.

    PubMed

    Paterson, Kevin B; Filik, Ruth; Liversedge, Simon P

    2008-03-01

    We investigated the processing of sentences containing a quantifier scope ambiguity, such as Kelly showed a photo to each critic, which is ambiguous between the indefinite phrase (a photo) having one or many referents. Ambiguity resolution requires the computation of relative quantifier scope, with either a photo or each critic taking wide scope, thereby determining the number of referents. Using eye tracking, we established that multiple factors, including the grammatical function and surface linear order of quantified phrases, along with their lexical characteristics, interact during the processing of relative quantifier scope, with conflict between factors incurring a processing cost. We discuss the results in terms of theoretical accounts attributing sentence-processing difficulty to either reanalysis (e.g., Fodor, 1982) or competition between rival analyses (e.g., Kurtzman & MacDonald, 1993).

  16. Perceptions of racial confrontation: the role of color blindness and comment ambiguity.

    PubMed

    Zou, Linda X; Dickter, Cheryl L

    2013-01-01

    Because of its emphasis on diminishing race and avoiding racial discourse, color-blind racial ideology has been suggested to have negative consequences for modern day race relations. The current research examined the influence of color blindness and the ambiguity of a prejudiced remark on perceptions of a racial minority group member who confronts the remark. One hundred thirteen White participants responded to a vignette depicting a White character making a prejudiced comment of variable ambiguity, after which a Black target character confronted the comment. Results demonstrated that the target confronter was perceived more negatively and as responding less appropriately by participants high in color blindness, and that this effect was particularly pronounced when participants responded to the ambiguous comment. Implications for the ways in which color blindness, as an accepted norm that is endorsed across legal and educational settings, can facilitate Whites' complicity in racial inequality are discussed.

  17. Kindergarten Children Can Be Taught to Detect Lexical Ambiguities

    ERIC Educational Resources Information Center

    Kamowski-Shakibai, Margaret T.; Cairns, Helen Smith

    2016-01-01

    This study investigates the development of metalinguistic skills, particularly ambiguity detection, and whether training accelerates this development for prereaders in kindergarten (5;5-6;6). It is the first to compare homophone detection with lexically ambiguous sentence detection in which the same homophones appear. The experimental group…

  18. Avoiding Attachment Ambiguities: The Role of Constituent Ordering

    ERIC Educational Resources Information Center

    Arnold, Jennifer E.; Wasow, Thomas; Asudeh, Ash; Alrenga, Peter

    2004-01-01

    Three experiments investigated whether speakers use constituent ordering as a mechanism for avoiding ambiguities. In utterances like ''Jane showed the letter to Mary to her mother,'' alternate orders would avoid the temporary PP-attachment ambiguity (''Jane showed her mother the letter to Mary,'' or ''Jane showed to her mother the letter to…

  19. The Learning Teacher: Role of Ambiguity in Education

    ERIC Educational Resources Information Center

    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…

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

    ERIC Educational Resources Information Center

    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…

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

    ERIC Educational Resources Information Center

    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…

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

    ERIC Educational Resources Information Center

    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…

  3. Semantic Ambiguity and the Process of Generating Meaning From Print

    ERIC Educational Resources Information Center

    Pexman, Penny M.; Hino, Yasushi; Lupker, Stephen J.

    2004-01-01

    An ambiguity disadvantage (slower responses for ambiguous words, e.g., bank, than for unambiguous words) has been reported in semantic tasks (L. R. Gottlob, S. D. Goldinger, G. O. Stone, & G. C. Van Orden, 1999; Y. Hino, S. J. Lupker, & P. M. Pexman, 2002; C. D. Piercey & S. Joordens, 2000) and has been attributed to the meaning activation…

  4. Modelling the Effects of Semantic Ambiguity in Word Recognition

    ERIC Educational Resources Information Center

    Rodd, Jennifer M.; Gaskell, M. Gareth; Marslen-Wilson, William D.

    2004-01-01

    Most words in English are ambiguous between different interpretations; words can mean different things in different contexts. We investigate the implications of different types of semantic ambiguity for connectionist models of word recognition. We present a model in which there is competition to activate distributed semantic representations. The…

  5. Rules for clinical diagnosis in babies with ambiguous genitalia.

    PubMed

    Low, Y; Hutson, J M

    2003-08-01

    Intersex disorders are rare and complex; yet, in each case of genital ambiguity, accurate and expeditious management is required of the clinician. This article reviews the embryology of sexual differentiation, from which some 'rules' of diagnosis are derived. A simplified approach to the interpretation of clinical signs in ambiguous genitalia is presented and discussed.

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

    ERIC Educational Resources Information Center

    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…

  7. The Effect of Role Ambiguity on Competitive State Anxiety.

    ERIC Educational Resources Information Center

    Beauchamp, Mark R.; Bray, Steven R.; Eys, Mark A.; Carron, Albert V.

    2003-01-01

    Investigated the relationship between role ambiguity and precompetition state anxiety among high school athletes playing field hockey. Surveys of male and female field hockey players in the United Kingdom indicated that ambiguity concerning the scope of one's offensive responsibilities was predictive cognitive state anxiety, while ambiguity…

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

    ERIC Educational Resources Information Center

    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…

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

    ERIC Educational Resources Information Center

    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…

  10. Cognitive Flexibility Supports Preschoolers' Detection of Communicative Ambiguity

    ERIC Educational Resources Information Center

    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…

  11. Not So Black and White: Memory for Ambiguous Group Members

    PubMed Central

    Pauker, Kristin; Weisbuch, Max; Ambady, Nalini; Sommers, Samuel R; Ivcevic, Zorana; Adams, Reginald B

    2013-01-01

    Exponential increases in multi-racial identities expected over the next century, creates a conundrum for perceivers accustomed to classifying people as “own” or “other” race. The current research examines how perceivers resolve this dilemma with regard to the “own-race bias.” We hypothesized that perceivers would not be motivated to include ambiguous-race individuals in the in-group and would therefore have some difficulty remembering them. Both racially-ambiguous and other-race faces were misremembered more often than own-race faces (Study 1), though memory for ambiguous faces was improved among perceivers motivated to include biracial individuals in the in-group (Study 2). Racial labels assigned to racially ambiguous faces determined memory for these faces, suggesting that uncertainty provides the motivational context for discounting ambiguous faces in memory (Study 3). Finally, an inclusion motivation fostered cognitive associations between racially-ambiguous faces and the in-group. Moreover, the extent to which perceivers associated racially-ambiguous faces with the in-group predicted memory for ambiguous faces and accounted for the impact of motivation on memory (Study 4). Thus, memory for biracial individuals seems to involve a flexible person construal process shaped by motivational factors. PMID:19309203

  12. GLONASS ionosphere-free ambiguity resolution for precise point positioning

    NASA Astrophysics Data System (ADS)

    Banville, Simon

    2016-05-01

    Current GLONASS satellites transmit signals based on the frequency division multiple access (FDMA) technology. Due to equipment delays occurring within GNSS receivers, GLONASS carrier phase and code observations are contaminated by inter-frequency biases. As a consequence, GLONASS ambiguity parameters in long-baseline processing are typically estimated as float values. In this paper, a strategy is investigated which benefits from the frequency spacing of GLONASS frequencies on the L1 and L2 bands, allowing for an ionosphere-free ambiguity with a wavelength of approximately 5 cm to be defined; therefore, avoiding the problematic wide-lane ambiguity resolution. Based on 12 independent baselines with a mean inter-station distance of about 850 km over a 1-week period, it is demonstrated that close to 95 % of the estimated double-differenced ionosphere-free ambiguities are within 0.15 cycles of an integer, thereby suggesting that long-baseline ambiguity resolution can be achieved for GLONASS. Applying between-station ambiguity constraints in precise point positioning (PPP) solutions was found to improve longitudinal repeatability in static mode by more than 20 % for sessions between 2 and 6 h in duration. In kinematic mode, only limited improvements were made to the initial convergence period since the short wavelength of GLONASS ionosphere-free ambiguities requires the solution to be nearly converged before successful ambiguity resolution can be achieved.

  13. Who is respectful? Effects of social context and individual empathic ability on ambiguity resolution during utterance comprehension

    PubMed Central

    Jiang, Xiaoming; Zhou, Xiaolin

    2015-01-01

    Verbal communication is often ambiguous. By employing the event-related potential (ERP) technique, this study investigated how a comprehender resolves referential ambiguity by using information concerning the social status of communicators. Participants read a conversational scenario which included a minimal conversational context describing a speaker and two other persons of the same or different social status and a directly quoted utterance. A singular, second-person pronoun in the respectful form (nin/nin-de in Chinese) in the utterance could be ambiguous with respect to which of the two persons was the addressee (the “Ambiguous condition”). Alternatively, the pronoun was not ambiguous either because one of the two persons was of higher social status and hence should be the addressee according to social convention (the “Status condition”) or because a word referring to the status of a person was additionally inserted before the pronoun to help indicate the referent of the pronoun (the “Referent condition”). Results showed that the perceived ambiguity decreased over the Ambiguous, Status, and Referent conditions. Electrophysiologically, the pronoun elicited an increased N400 in the Referent than in the Status and the Ambiguous conditions, reflecting an increased integration demand due to the necessity of linking the pronoun to both its antecedent and the status word. Relative to the Referent condition, a late, sustained positivity was elicited for the Status condition starting from 600 ms, while a more delayed, anterior negativity was elicited for the Ambiguous condition. Moreover, the N400 effect was modulated by individuals' sensitivity to the social status information, while the late positivity effect was modulated by individuals' empathic ability. These findings highlight the neurocognitive flexibility of contextual bias in referential processing during utterance comprehension. PMID:26557102

  14. Family care giving: what price love?

    PubMed

    Sterneck, J G

    1990-01-01

    The role played by family care givers is critical to the well-being of their impaired elderly family members and to the well-being of society as a whole. Studies indicate that a key determinant of institutional placement is the breakdown of an older person's informal caregiving system. Given the demographics of our aging population and the medical advancements of recent years, the giving and receiving of care is an issue that will affect most individuals' daily lives during some part of the life cycle. The responsibilities for giving care will continue to fall more and more disproportionately upon elderly spouses who themselves may have health problems and upon daughters and daughters-in-law who often have work commitments outside the home and young children in the home. Giving care often results in financial, physical, social, and emotional problems and stresses. Current demographic trends such as marriage at a later age, the increasing number of divorces, fewer and later births, and the rising number of women in the work force will only serve to complicate the role conflicts and exacerbate the stresses of care giving on family members. In order for family care giving to continue--indeed, to raise it to a more productive and satisfactory level--a range of supportive fiscal, medical, and social services must be provided to families. National public policy must begin to address the needs of families by supporting options other than institutional care for the disabled elderly.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:10106870

  15. Ambiguous taxa: Effects on the characterization and interpretation of invertebrate assemblages

    USGS Publications Warehouse

    Cuffney, T.F.; Bilger, M.D.; Haigler, A.M.

    2007-01-01

    Damaged and immature specimens often result in macroinvertebrate data that contain ambiguous parent-child pairs (i.e., abundances associated with multiple related levels of the taxonomic hierarchy such as Baetis pluto and the associated ambiguous parent Baetis sp.). The choice of method used to resolve ambiguous parent-child pairs may have a very large effect on the characterization of invertebrate assemblages and the interpretation of responses to environmental change because very large proportions of taxa richness (73-78%) and abundance (79-91%) can be associated with ambiguous parents. To address this issue, we examined 16 variations of 4 basic methods for resolving ambiguous taxa: RPKC (remove parent, keep child), MCWP (merge child with parent), RPMC (remove parent or merge child with parent depending on their abundances), and DPAC (distribute parents among children). The choice of method strongly affected assemblage structure, assemblage characteristics (e.g., metrics), and the ability to detect responses along environmental (urbanization) gradients. All methods except MCWP produced acceptable results when used consistently within a study. However, the assemblage characteristics (e.g., values of assemblage metrics) differed widely depending on the method used, and data should not be combined unless the methods used to resolve ambiguous taxa are well documented and are known to be comparable. The suitability of the methods was evaluated and compared on the basis of 13 criteria that considered conservation of taxa richness and abundance, consistency among samples, methods, and studies, and effects on the interpretation of the data. Methods RPMC and DPAC had the highest suitability scores regardless of whether ambiguous taxa were resolved for each sample separately or for a group of samples. Method MCWP gave consistently poor results. Methods MCWP and DPAC approximate the use of family-level identifications and operational taxonomic units (OTU), respectively. Our

  16. Strong-coupling study of the Gribov ambiguity in lattice Landau gauge

    NASA Astrophysics Data System (ADS)

    Maas, Axel; Pawlowski, Jan M.; Spielmann, Daniel; Sternbeck, André; von Smekal, Lorenz

    2010-07-01

    We study the strong-coupling limit β=0 of lattice SU(2) Landau gauge Yang-Mills theory. In this limit the lattice spacing is infinite, and thus all momenta in physical units are infinitesimally small. Hence, the infrared behavior can be assessed at sufficiently large lattice momenta. Our results show that at the lattice volumes used here, the Gribov ambiguity has an enormous effect on the ghost propagator in all dimensions. This underlines the severity of the Gribov problem and calls for refined studies also at finite β. In turn, the gluon propagator only mildly depends on the Gribov ambiguity.

  17. Role-modeling and conversations about giving in the socialization of adolescent charitable giving and volunteering.

    PubMed

    Ottoni-Wilhelm, Mark; Estell, David B; Perdue, Neil H

    2014-01-01

    This study investigated the relationship between the monetary giving and volunteering behavior of adolescents and the role-modeling and conversations about giving provided by their parents. The participants are a large nationally-representative sample of 12-18 year-olds from the Panel Study of Income Dynamics' Child Development Supplement (n = 1244). Adolescents reported whether they gave money and whether they volunteered. In a separate interview parents reported whether they talked to their adolescent about giving. In a third interview, parents reported whether they gave money and volunteered. The results show that both role-modeling and conversations about giving are strongly related to adolescents' giving and volunteering. Knowing that both role-modeling and conversation are strongly related to adolescents' giving and volunteering suggests an often over-looked way for practitioners and policy-makers to nurture giving and volunteering among adults: start earlier, during adolescence, by guiding parents in their role-modeling of, and conversations about, charitable giving and volunteering.

  18. Role-modeling and conversations about giving in the socialization of adolescent charitable giving and volunteering.

    PubMed

    Ottoni-Wilhelm, Mark; Estell, David B; Perdue, Neil H

    2014-01-01

    This study investigated the relationship between the monetary giving and volunteering behavior of adolescents and the role-modeling and conversations about giving provided by their parents. The participants are a large nationally-representative sample of 12-18 year-olds from the Panel Study of Income Dynamics' Child Development Supplement (n = 1244). Adolescents reported whether they gave money and whether they volunteered. In a separate interview parents reported whether they talked to their adolescent about giving. In a third interview, parents reported whether they gave money and volunteered. The results show that both role-modeling and conversations about giving are strongly related to adolescents' giving and volunteering. Knowing that both role-modeling and conversation are strongly related to adolescents' giving and volunteering suggests an often over-looked way for practitioners and policy-makers to nurture giving and volunteering among adults: start earlier, during adolescence, by guiding parents in their role-modeling of, and conversations about, charitable giving and volunteering. PMID:24331305

  19. [Technological innovation and healthcare professionals' workloads: an ambiguous relationship].

    PubMed

    de Pires, Denise Elvira Pires; Bertoncini, Judite Hennemann; Trindade, Letícia de Lima; Matos, Eliane; Azambuja, Eliana; Borges, Ana Maria Fernandes

    2012-03-01

    This is an integrative review with the aim of tracing the scientific production concerning the influence of technological innovation in health care professionals' workloads. Fifty-seven (57) publications presented from 2004 to 2009 were selected from the LILACS and PubMed databases. In the selected studies field research using qualitative approaches and carried out in hospitals predominated. No study had the purpose to analyze the relationship between technological innovation and workloads. In studies involving technological innovation, publications concerning information and communication technologies and new forms of work organizations were highlighted studies concerning conditions which promote stress and Burnout predominated in the workloads theme. Results show an ambiguous relationship between technological innovation and workloads, which are either increased or diminished by innovations. PMID:22737809

  20. Resolution of lexical ambiguity by emotional tone of voice.

    PubMed

    Nygaard, Lynne C; Lunders, Erin R

    2002-06-01

    In the present study, the effects of emotional tone of voice on the perception of word meaning were investigated. In two experiments, listeners were presented with emotional homophones that had one affective meaning (happy or sad) and one neutral meaning. In both experiments, the listeners were asked to transcribe the emotional homophones presented in three different affective tones--happy, neutral, and sad. In the first experiment, trials were blocked by tone of voice, and in the second experiment, tone of voice varied from trial to trial. The results showed that the listeners provided more affective than neutral transcriptions when the tone of voice was congruent with the emotional meaning of the homophone. These findings suggest that emotional tone of voice affects the processing of lexically ambiguous words by biasing the selection of word meaning.

  1. Actively learning object names across ambiguous situations.

    PubMed

    Kachergis, George; Yu, Chen; Shiffrin, Richard M

    2013-01-01

    Previous research shows that people can use the co-occurrence of words and objects in ambiguous situations (i.e., containing multiple words and objects) to learn word meanings during a brief passive training period (Yu & Smith, 2007). However, learners in the world are not completely passive but can affect how their environment is structured by moving their heads, eyes, and even objects. These actions can indicate attention to a language teacher, who may then be more likely to name the attended objects. Using a novel active learning paradigm in which learners choose which four objects they would like to see named on each successive trial, this study asks whether active learning is superior to passive learning in a cross-situational word learning context. Finding that learners perform better in active learning, we investigate the strategies and discover that most learners use immediate repetition to disambiguate pairings. Unexpectedly, we find that learners who repeat only one pair per trial--an easy way to infer this pair-perform worse than those who repeat multiple pairs per trial. Using a working memory extension to an associative model of word learning with uncertainty and familiarity biases, we investigate individual differences that correlate with these assorted strategies. PMID:23335580

  2. Ambiguity resolved precise point positioning with GPS and BeiDou

    NASA Astrophysics Data System (ADS)

    Pan, Li; Xiaohong, Zhang; Fei, Guo

    2016-07-01

    This paper focuses on the contribution of the global positioning system (GPS) and BeiDou navigation satellite system (BDS) observations to precise point positioning (PPP) ambiguity resolution (AR). A GPS + BDS fractional cycle bias (FCB) estimation method and a PPP AR model were developed using integrated GPS and BDS observations. For FCB estimation, the GPS + BDS combined PPP float solutions of the globally distributed IGS MGEX were first performed. When integrating GPS observations, the BDS ambiguities can be precisely estimated with less than four tracked BDS satellites. The FCBs of both GPS and BDS satellites can then be estimated from these precise ambiguities. For the GPS + BDS combined AR, one GPS and one BDS IGSO or MEO satellite were first chosen as the reference satellite for GPS and BDS, respectively, to form inner-system single-differenced ambiguities. The single-differenced GPS and BDS ambiguities were then fused by partial ambiguity resolution to increase the possibility of fixing a subset of decorrelated ambiguities with high confidence. To verify the correctness of the FCB estimation and the effectiveness of the GPS + BDS PPP AR, data recorded from about 75 IGS MGEX stations during the period of DOY 123-151 (May 3 to May 31) in 2015 were used for validation. Data were processed with three strategies: BDS-only AR, GPS-only AR and GPS + BDS AR. Numerous experimental results show that the time to first fix (TTFF) is longer than 6 h for the BDS AR in general and that the fixing rate is usually less than 35 % for both static and kinematic PPP. An average TTFF of 21.7 min and 33.6 min together with a fixing rate of 98.6 and 97.0 % in static and kinematic PPP, respectively, can be achieved for GPS-only ambiguity fixing. For the combined GPS + BDS AR, the average TTFF can be shortened to 16.9 min and 24.6 min and the fixing rate can be increased to 99.5 and 99.0 % in static and kinematic PPP, respectively. Results also show that GPS + BDS PPP AR outperforms

  3. Explaining Role Conflict and Role Ambiguity Via Individual and Interpersonal Variables in Different Job Categories.

    ERIC Educational Resources Information Center

    Randolph, W. Alan; Posner, Barry Z.

    1981-01-01

    Examined relationships between experiencing role conflict and ambiguity and four individual and interpersonal variables. Results suggest that the underlying equations regarding the influence of individual and interpersonal variables on role perceptions vary in different job categories. Task characteristics are offered as plausible reasons for…

  4. Essentialist Thinking Predicts Decrements in Children's Memory for Racially Ambiguous Faces

    ERIC Educational Resources Information Center

    Gaither, Sarah E.; Schultz, Jennifer R.; Pauker, Kristin; Sommers, Samuel R.; Maddox, Keith B.; Ambady, Nalini

    2014-01-01

    Past research shows that adults often display poor memory for racially ambiguous and racial outgroup faces, with both face types remembered worse than own-race faces. In the present study, the authors examined whether children also show this pattern of results. They also examined whether emerging essentialist thinking about race predicts…

  5. Effect of Prefrontal Cortex Damage on Resolving Lexical Ambiguity in Text

    ERIC Educational Resources Information Center

    Frattali, Carol; Hanna, Rebecca; McGinty, Anita Shukla; Gerber, Lynn; Wesley, Robert; Grafman, Jordan; Coelho, Carl

    2007-01-01

    The function of suppression of context-inappropriate meanings during lexical ambiguity resolution was examined in 25 adults with prefrontal cortex damage (PFCD) localized to the left (N = 8), right (N = 6), or bilaterally (N = 11); and 21 matched Controls. Results revealed unexpected inverse patterns of suppression between PFCD and Control groups,…

  6. Responding to Ambiguity, Responding to Change the Value of a Responsive Approach to Evaluation.

    ERIC Educational Resources Information Center

    Abma, T. A.

    2000-01-01

    Evaluated the success of a palliative health care team in a Dutch health region. Results show that it is more appropriate to acknowledge ambiguity and facilitate its handling as part of dynamic learning processes. Discusses the usefulness of a responsive approach to evaluation, evaluation methodology, and learning experiences. (SLD)

  7. Resolving the 180-degree ambiguity in vector magnetic field measurements: The 'minimum' energy solution

    NASA Technical Reports Server (NTRS)

    Metcalf, Thomas R.

    1994-01-01

    I present a robust algorithm that resolves the 180-deg ambiguity in measurements of the solar vector magnetic field. The technique simultaneously minimizes both the divergence of the magnetic field and the electric current density using a simulated annealing algorithm. This results in the field orientation with approximately minimum free energy. The technique is well-founded physically and is simple to implement.

  8. Conflict and Ambiguity over Work Roles: The Impact on Child Care Worker Burnout.

    ERIC Educational Resources Information Center

    Manlove, Elizabeth

    1994-01-01

    Examined the relation of occupational stress in the child care workplace to three facets of staff burnout: emotional exhaustion; depersonalization; and personal accomplishment. Results showed that work role conflict and ambiguity predicted a significant portion of variance in the three aspects of staff burnout, and that social support buffered the…

  9. N400 to Lexical Ambiguity and Semantic Incongruity in Schizophrenia

    PubMed Central

    Salisbury, Dean

    2009-01-01

    Our previous work showed a semantic bias in interpreting ambiguous words in schizophrenia, with disproportionate misinterpretation of subordinate meanings (toast at a wedding). We proposed pre-selection in schizophrenia of dominant meaning networks at points of lexical ambiguity, thereby misleading thought. This selection bias may be due to semantic memory hyper-priming causing strong associates to dominate cognition. Alternately, later access verbal memory maintenance failure may cause weaker associates to fade more quickly than stronger associates from memory due to less initial activation. To further examine this semantic bias, patients and controls were presented short 4 word long sentences (The toast was buttered). The second word was a homograph or unambiguous noun. The last word disambiguated homographs (dominant or subordinate meaning) or was congruent or incongruent with unambiguous nouns. Previously, we showed increasingly larger N400 from unambiguous associates to dominate associates to subordinate associates to unambiguous non-associates in controls. Pre-selection of dominant meanings predicts schizophrenia patients would show small N400 to dominant associates and as large N400 to subordinate associates as to incongruous endings. Here, controls again showed graded N400 amplitudes. Patients with schizophrenia showed small N400 to congruent and dominant endings and large N400 to subordinate and incongruous endings. These data suggest early pre-selection of dominant associates in schizophrenia. This effect is unlikely solely due to verbal memory maintenance failure, as patients were able to detect incongruity, albeit with a smaller N400 effect, and generally larger N400 to all stimuli. These results suggest alterations in semantic memory associative networks coupled with verbal working memory maintenance decay in schizophrenia. PMID:19819269

  10. Assimilating ambiguous observations to jointly estimate groundwater recharge and conductivity

    NASA Astrophysics Data System (ADS)

    Erdal, Daniel; Cirpka, Olaf A.

    2016-04-01

    In coupled modelling of catchments, the groundwater compartment can be an important water storage as well as having influence on both rivers and evapotranspirational fluxes. It is therefore important to parameterize the groundwater model as correctly as possible. Primarily important to regional groundwater flow is the spatially variable hydraulic conductivity. However, also the groundwater recharge, in a coupled system coming from the unsaturated zone but in a stand-alone groundwater model a boundary condition, is also of high importance. As with all subsurface systems, groundwater properties are difficult to observe in reality and their estimation is an ongoing topic in groundwater research and practice. Commonly, we have to rely on time series of groundwater head observations as base for any parameter estimation. Heads, however, have the drawback that they can be ambiguous and may not uniquely define the inverse problem, especially if both recharge and conductivity are seen as unknown. In the presented work we use a 2D virtual groundwater test case to investigate how the prior knowledge of recharge and conductivity influence their respective and joint estimation as spatially variable fields using head data. Using the Ensemble Kalman filter, it is shown that the joint estimation is possible if the prior knowledge is good enough. If the prior is erroneous the a-priori sampled fields cannot be corrected by the data. However, it is also shown that if the prior knowledge is directly wrong the estimated recharge field can resemble the true conductivity field, resulting in a model that meets the observations but has very poor predictive power. The study exemplifies the importance of prior knowledge in the joint estimation of parameters from ambiguous measurements.

  11. Ambiguity and the image of the king.

    PubMed

    Mack, R T

    1994-01-01

    The following essay explores problems posed by a recently-published fresco (dated to the first century AD) that depicts Alexander the Great standing opposite an unknown female figure. The fresco is unusual in its use of conventional or codified figure types, in particular a widely-found statue type known as the "Alexander with the Lance," and for its placement of Alexander in anecdotal relation with a woman. While discussions of the picture thus far have tried to identify the scene depicted (by reference to histories of Alexander's life), the following analysis takes the difficulty of doing so itself as a motivated aspect of the image. I argue that the fresco's mode of representation is to bring together figure types whose conventional fields of meaning are in conflict with one another, and then to highlight this conflict in order to comment upon the fields (or figure types) themselves. In this case, the fresco's ambiguity in signification (the undecidability of its reference) enables a highly strategic critique of the "Alexander with the Lance" because the latter, as a prototypical "image of the king," depends upon the necessary and transparent extension of its signs. By virtue of the anecdotal relation between "Alexander" and the depicted female figure (an Aphrodite type) the fresco's critique reveals the close association between the claims for representation made by the image of the king and the patriarchal structures of power they seek to instantiate. The fresco thus offers remarkably direct data for understanding the intersection of representation and gender in the early Roman empire. I suggest in conclusion that because the image seems also to posit a specifically gendered (male) gaze, its critique is extended to the spectator and thereby provides data for understanding the intersection of the practice of representation (here, viewing) and gender.

  12. Reaction Order Ambiguity in Integrated Rate Plots

    ERIC Educational Resources Information Center

    Lee, Joe

    2008-01-01

    Integrated rate plots are frequently used in reaction kinetics to determine orders of reactions. It is often emphasised, when using this methodology in practice, that it is necessary to monitor the reaction to a substantial fraction of completion for these plots to yield unambiguous orders. The present article gives a theoretical and statistical…

  13. Stimulating the brain's language network: syntactic ambiguity resolution after TMS to the inferior frontal gyrus and middle temporal gyrus.

    PubMed

    Acheson, Daniel J; Hagoort, Peter

    2013-10-01

    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 information and the IFG in unification operations that maintain, select, and integrate multiple sources of information over time. In the present investigation, we tested for causal evidence of this dissociation by modulating activity in IFG and MTG using an offline TMS procedure: continuous theta-burst stimulation. Lexical-syntactic retrieval was manipulated by using sentences with and without a temporarily word-class (noun/verb) ambiguity (e.g., run). In one group of participants, TMS was applied to the IFG and MTG, and in a control group, no TMS was applied. Eye movements were recorded and quantified at two critical sentence regions: a temporarily ambiguous region and a disambiguating region. Results show that stimulation of the IFG led to a modulation of the ambiguity effect (ambiguous-unambiguous) at the disambiguating sentence region in three measures: first fixation durations, total reading times, and regressive eye movements into the region. Both IFG and MTG stimulation modulated the ambiguity effect for total reading times in the temporarily ambiguous sentence region relative to the control group. The current results demonstrate that an offline repetitive TMS protocol can have influences at a different point in time during online processing and provide causal evidence for IFG involvement in unification operations during sentence comprehension.

  14. The truth about chickens and bats: ambiguity avoidance distinguishes types of polysemy.

    PubMed

    Rabagliati, Hugh; Snedeker, Jesse

    2013-07-01

    Words mean different things in different contexts, a phenomenon called polysemy. People talk about lines of both people and poetry, and about both long distances and long times. Polysemy lets a limited vocabulary capture a great variety of experiences, while highlighting commonalities. But how is this achieved? Are polysemous senses contextually driven modifications of core meanings, or must each sense be memorized separately? We show that participants' ability to avoid referentially ambiguous descriptions of pictures named by polysemous words provides evidence for both possibilities. When senses followed a regular pattern (e.g., animals and the foodstuffs derived from them; noisy chicken, tasty chicken), participants avoided using ambiguous labels in referentially ambiguous situations (e.g., both types of chicken were present), a result indicating that they noticed a common meaning. But when senses were idiosyncratically related (e.g., sheet of glass, drinking glass), participants frequently produced ambiguous labels, a result indicating that the meanings were separately stored. We discuss implications for the relationship between word meanings and concepts.

  15. A geometry-free and ionosphere-free multipath mitigation method for BDS three-frequency ambiguity resolution

    NASA Astrophysics Data System (ADS)

    Chen, Dezhong; Ye, Shirong; Xia, Jingchao; Liu, Yanyan; Xia, Pengfei

    2016-08-01

    Because of the unknown systematic errors and special satellite constellations in the Beidou system (BDS), it is difficult to quickly and reliably determine the ambiguity over long-range baselines in continuously operating reference station (CORS) network. This study seeks to improve the effectiveness and reliability of BDS ambiguity resolution (AR) by combining the geometry-free and ionosphere-free (GFIF) combination and multipath mitigation algorithm. The GFIF combination composed with three-frequency signals is free of distance-dependent errors and can be used to determine the narrow lane ambiguity. The presence of multipath errors means that not all ambiguities can be correctly achieved by rounding the averaged GFIF ambiguity series. A multipath model of the single-differenced (SD) GFIF combination from the previous period is established for each individual satellite. This model is subtracted from the SD GFIF combination for the current day to remove the effects of multipath errors. Using three triangle networks with lengths of approximately 120, 80 and 50 km, we demonstrate that the proposed method improves the AR performance. The ambiguity averaged first fixing time is typically less than 1801 s for inclined geosynchronous orbit (IGSO) and medium earth orbit (MEO) satellites and less than 2007 s for the ˜ 42° elevation geostationary earth orbit (GEO) C02 satellite. However, it is more time consuming for the low-elevation GEO satellites C04 (˜ 18°) and C05 (˜ 28°). Kalman filtering is used to estimate the troposphere delays and two unfixed ambiguities by employing the ionosphere-free observations of all ambiguity-fixed/unfixed satellites. The experimental results show that only tens of seconds are required for AR in around 90 km baselines.

  16. Cross ambiguity functions on the MasPar MP-2

    SciTech Connect

    Carlson, D.A.; Pryor, D.V.; Frock, C.K.

    1995-12-01

    In a signal processing environment, cross ambiguity functions are often used to detect when one signal is a time and/or frequency shift of another. They consist of multiple cross-correlations, which can be computed efficiently using complex valued FFTs. This paper discusses the implementation of cross ambiguity functions on the MasPar MP-2, a SIMD processor array. Two different implementations are developed. The first computes each cross ambiguity function serially, using FFT code that parallelizes across the complete set of processors. The second uses the MasPar IORAM to realign the data so that the cross ambiguity functions can be computed in parallel. In this case, multiple FFTs are executed in parallel on subsets of the processors, which lowers the overall amount of communication required.

  17. Ambiguity Of Doppler Centroid In Synthetic-Aperture Radar

    NASA Technical Reports Server (NTRS)

    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.

  18. Top-down influence in young children's linguistic ambiguity resolution.

    PubMed

    Rabagliati, Hugh; Pylkkänen, Liina; Marcus, Gary F

    2013-06-01

    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 linguistic ambiguity resolution by evaluating whether children rely largely or completely on lexical associations to resolve lexical ambiguities (e.g., the word swing primes the baseball meaning of bat) or additionally integrate top-down global plausibility. Using a picture choice task, we compared 4-year-olds' ability to resolve polysemes and homophones with a Bayesian algorithm reliant purely on lexical associations and found that the algorithm's power to predict children's choices was limited. A 2nd experiment confirmed that children override associations and integrate top-down plausibility. We discuss this with regard to models of psycholinguistic development. PMID:22229852

  19. Top-down influence in young children's linguistic ambiguity resolution.

    PubMed

    Rabagliati, Hugh; Pylkkänen, Liina; Marcus, Gary F

    2013-06-01

    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 linguistic ambiguity resolution by evaluating whether children rely largely or completely on lexical associations to resolve lexical ambiguities (e.g., the word swing primes the baseball meaning of bat) or additionally integrate top-down global plausibility. Using a picture choice task, we compared 4-year-olds' ability to resolve polysemes and homophones with a Bayesian algorithm reliant purely on lexical associations and found that the algorithm's power to predict children's choices was limited. A 2nd experiment confirmed that children override associations and integrate top-down plausibility. We discuss this with regard to models of psycholinguistic development.

  20. Functional neuroimaging of grammatical class: ambiguous and unambiguous nouns and verbs.

    PubMed

    Burton, Martha W; Krebs-Noble, Donna; Gullapalli, Rao P; Berndt, Rita Sloan

    2009-03-01

    Neuropsychological and neuroimaging studies of grammatical-class differences suggest that nouns and verbs may be associated with different brain regions. The current functional magnetic resonance imaging (fMRI) study focused on auditory grammaticality judgements of two-word stimuli consisting of noun/verb ambiguous and unambiguous nouns and verbs preceded by either "the" or "to". The fMRI results showed effects of class ambiguity in the left inferior frontal gyrus, possibly due to greater selection demands, and effects of grammaticality ("yes" vs. "no" response) in left superior temporal gyrus, consistent with greater activation for trials with greater conflict. In addition, posterior left temporal lobe regions showed increased activity on unambiguous trials for verbs than for nouns, consistent with prior imaging studies. Thus, in a task specifically focused on the grammatical (rather than semantic) aspects of words and that used morphologically simple nouns and verbs controlled for imageability, verbs preferentially activated posterior temporal but not frontal lobe regions. However, for ambiguous trials in this same region, nouns showed greater activation than verbs, suggesting that these effects can be modulated by class ambiguity.

  1. Implementation ambiguity: The fifth element long lost in uncertainty budgets for land biogeochemical modeling

    NASA Astrophysics Data System (ADS)

    Tang, J.; Riley, W. J.

    2015-12-01

    Previous studies have identified four major sources of predictive uncertainty in modeling land biogeochemical (BGC) processes: (1) imperfect initial conditions (e.g., assumption of preindustrial equilibrium); (2) imperfect boundary conditions (e.g., climate forcing data); (3) parameterization (type I equifinality); and (4) model structure (type II equifinality). As if that were not enough to cause substantial sleep loss in modelers, we propose here a fifth element of uncertainty that results from implementation ambiguity that occurs when the model's mathematical description is translated into computational code. We demonstrate the implementation ambiguity using the example of nitrogen down regulation, a necessary process in modeling carbon-climate feedbacks. We show that, depending on common land BGC model interpretations of the governing equations for mineral nitrogen, there are three different implementations of nitrogen down regulation. We coded these three implementations in the ACME land model (ALM), and explored how they lead to different preindustrial and contemporary land biogeochemical states and fluxes. We also show how this implementation ambiguity can lead to different carbon-climate feedback estimates across the RCP scenarios. We conclude by suggesting how to avoid such implementation ambiguity in ESM BGC models.

  2. Developing a measure of interpretation bias for depressed mood: An ambiguous scenarios test

    PubMed Central

    Berna, Chantal; Lang, Tamara J.; Goodwin, Guy M.; Holmes, Emily A.

    2011-01-01

    The tendency to interpret ambiguous everyday situations in a relatively negative manner (negative interpretation bias) is central to cognitive models of depression. Limited tools are available to measure this bias, either experimentally or in the clinic. This study aimed to develop a pragmatic interpretation bias measure using an ambiguous scenarios test relevant to depressed mood (the AST-D).1 In Study 1, after a pilot phase (N = 53), the AST-D was presented via a web-based survey (N = 208). Participants imagined and rated each AST-D ambiguous scenario. As predicted, higher dysphoric mood was associated with lower pleasantness ratings (more negative bias), independent of mental imagery measures. In Study 2, self-report ratings were compared with objective ratings of participants’ imagined outcomes of the ambiguous scenarios (N = 41). Data were collected in the experimental context of a functional Magnetic Resonance Imaging scanner. Consistent with subjective bias scores, independent judges rated more sentences as negatively valenced for the high versus low dysphoric group. Overall, results suggest the potential utility of the AST-D in assessing interpretation bias associated with depressed mood. PMID:21822348

  3. Diagnosing children's writing disabilities: different tests give different results.

    PubMed

    Mayes, Susan D; Calhoun, Susan L; Lane, Susan E

    2005-08-01

    Writing problems are common in children with clinical disorders. However, there are significant intra-individual differences between the ability to spell words, construct sentences, and compose text. Therefore, achievement tests measuring different writing skills may not be consistent in identifying children who have these various writing disabilities. Our study compared scores on the Woodcock-Johnson Written Language subtests (which measure the ability to produce single words and single sentences) with scores on the Wechsler Individual Achievement Test Written Expression subtest (which assesses compositional writing skills) in 54 children referred by their teachers to a school psychologist for writing problems. The Woodcock-Johnson only identified 35% of children as having significant writing problems, whereas the Wechsler test identified 78%. Our study suggests that the latter is more likely than the Woodcock-Johnson to identify students who have problems in compositional writing.

  4. Improving Ambiguity Resolution for Medium Baselines Using Combined GPS and BDS Dual/Triple-Frequency Observations.

    PubMed

    Gao, Wang; Gao, Chengfa; Pan, Shuguo; Wang, Denghui; Deng, Jiadong

    2015-01-01

    The regional constellation of the BeiDou navigation satellite system (BDS) has been providing continuous positioning, navigation and timing services since 27 December 2012, covering China and the surrounding area. Real-time kinematic (RTK) positioning with combined BDS and GPS observations is feasible. Besides, all satellites of BDS can transmit triple-frequency signals. Using the advantages of multi-pseudorange and carrier observations from multi-systems and multi-frequencies is expected to be of much benefit for ambiguity resolution (AR). We propose an integrated AR strategy for medium baselines by using the combined GPS and BDS dual/triple-frequency observations. In the method, firstly the extra-wide-lane (EWL) ambiguities of triple-frequency system, i.e., BDS, are determined first. Then the dual-frequency WL ambiguities of BDS and GPS were resolved with the geometry-based model by using the BDS ambiguity-fixed EWL observations. After that, basic (i.e., L1/L2 or B1/B2) ambiguities of BDS and GPS are estimated together with the so-called ionosphere-constrained model, where the ambiguity-fixed WL observations are added to enhance the model strength. During both of the WL and basic AR, a partial ambiguity fixing (PAF) strategy is adopted to weaken the negative influence of new-rising or low-elevation satellites. Experiments were conducted and presented, in which the GPS/BDS dual/triple-frequency data were collected in Nanjing and Zhengzhou of China, with the baseline distance varying from about 28.6 to 51.9 km. The results indicate that, compared to the single triple-frequency BDS system, the combined system can significantly enhance the AR model strength, and thus improve AR performance for medium baselines with a 75.7% reduction of initialization time on average. Besides, more accurate and stable positioning results can also be derived by using the combined GPS/BDS system. PMID:26528977

  5. Improving Ambiguity Resolution for Medium Baselines Using Combined GPS and BDS Dual/Triple-Frequency Observations

    PubMed Central

    Gao, Wang; Gao, Chengfa; Pan, Shuguo; Wang, Denghui; Deng, Jiadong

    2015-01-01

    The regional constellation of the BeiDou navigation satellite system (BDS) has been providing continuous positioning, navigation and timing services since 27 December 2012, covering China and the surrounding area. Real-time kinematic (RTK) positioning with combined BDS and GPS observations is feasible. Besides, all satellites of BDS can transmit triple-frequency signals. Using the advantages of multi-pseudorange and carrier observations from multi-systems and multi-frequencies is expected to be of much benefit for ambiguity resolution (AR). We propose an integrated AR strategy for medium baselines by using the combined GPS and BDS dual/triple-frequency observations. In the method, firstly the extra-wide-lane (EWL) ambiguities of triple-frequency system, i.e., BDS, are determined first. Then the dual-frequency WL ambiguities of BDS and GPS were resolved with the geometry-based model by using the BDS ambiguity-fixed EWL observations. After that, basic (i.e., L1/L2 or B1/B2) ambiguities of BDS and GPS are estimated together with the so-called ionosphere-constrained model, where the ambiguity-fixed WL observations are added to enhance the model strength. During both of the WL and basic AR, a partial ambiguity fixing (PAF) strategy is adopted to weaken the negative influence of new-rising or low-elevation satellites. Experiments were conducted and presented, in which the GPS/BDS dual/triple-frequency data were collected in Nanjing and Zhengzhou of China, with the baseline distance varying from about 28.6 to 51.9 km. The results indicate that, compared to the single triple-frequency BDS system, the combined system can significantly enhance the AR model strength, and thus improve AR performance for medium baselines with a 75.7% reduction of initialization time on average. Besides, more accurate and stable positioning results can also be derived by using the combined GPS/BDS system. PMID:26528977

  6. Spontaneous giving and calculated greed.

    PubMed

    Rand, David G; Greene, Joshua D; Nowak, Martin A

    2012-09-20

    Cooperation is central to human social behaviour. However, choosing to cooperate requires individuals to incur a personal cost to benefit others. Here we explore the cognitive basis of cooperative decision-making in humans using a dual-process framework. We ask whether people are predisposed towards selfishness, behaving cooperatively only through active self-control; or whether they are intuitively cooperative, with reflection and prospective reasoning favouring 'rational' self-interest. To investigate this issue, we perform ten studies using economic games. We find that across a range of experimental designs, subjects who reach their decisions more quickly are more cooperative. Furthermore, forcing subjects to decide quickly increases contributions, whereas instructing them to reflect and forcing them to decide slowly decreases contributions. Finally, an induction that primes subjects to trust their intuitions increases contributions compared with an induction that promotes greater reflection. To explain these results, we propose that cooperation is intuitive because cooperative heuristics are developed in daily life where cooperation is typically advantageous. We then validate predictions generated by this proposed mechanism. Our results provide convergent evidence that intuition supports cooperation in social dilemmas, and that reflection can undermine these cooperative impulses.

  7. Giving curriculum planners an edge

    PubMed Central

    Oandasan, Ivy F.; Archibald, Douglas; Authier, Louise; Lawrence, Kathrine; McEwen, Laura April; Palacios, Maria; Parkkari, Marie; Plant, Heidi; Slade, Steve; Ross, Shelley

    2015-01-01

    Abstract Objective To pilot a survey of family medicine residents entering residency, describing their exposure to family medicine and their perspectives related to their future intentions to practise family medicine, in order to inform curriculum planners; and to test the methodology, feasibility, and utility of delivering a longitudinal survey to multiple residency programs. Design Pilot study using surveys. Setting Five Canadian residency programs. Participants A total of 454 first-year family medicine residents were surveyed. Main outcome measures Residents’ previous exposure to family medicine, perspectives on family medicine, and future practice intentions. Results Overall, 70% of first-year residents surveyed responded (n = 317). Although only 5 residency programs participated, respondents included graduates from each of the medical schools in Canada, as well as international medical graduates. Among respondents, 92% felt positive or strongly positive about their choice to be family physicians. Most (73%) indicated they had strong or very strong exposure to family medicine in medical school, yet more than 40% had no or minimal exposure to key clinical domains of family medicine like palliative care, home care, and care of underserved groups. Similar responses were found about residents’ lack of intention to practise in these domains. Conclusion Exposure to clinical domains in family medicine could influence future practice intentions. Surveys at entrance to residency can help medical school and family medicine residency planners consider important learning experiences to include in training. PMID:26052601

  8. Preventing Data Ambiguity in Infectious Diseases with Four-Dimensional and Personalized Evaluations

    PubMed Central

    Iandiorio, Michelle J.; Fair, Jeanne M.; Chatzipanagiotou, Stylianos; Ioannidis, Anastasios; Trikka-Graphakos, Eleftheria; Charalampaki, Nikoletta; Sereti, Christina; Tegos, George P.; Hoogesteijn, Almira L.; Rivas, Ariel L.

    2016-01-01

    Background Diagnostic errors can occur, in infectious diseases, when anti-microbial immune responses involve several temporal scales. When responses span from nanosecond to week and larger temporal scales, any pre-selected temporal scale is likely to miss some (faster or slower) responses. Hoping to prevent diagnostic errors, a pilot study was conducted to evaluate a four-dimensional (4D) method that captures the complexity and dynamics of infectious diseases. Methods Leukocyte-microbial-temporal data were explored in canine and human (bacterial and/or viral) infections, with: (i) a non-structured approach, which measures leukocytes or microbes in isolation; and (ii) a structured method that assesses numerous combinations of interacting variables. Four alternatives of the structured method were tested: (i) a noise-reduction oriented version, which generates a single (one data point-wide) line of observations; (ii) a version that measures complex, three-dimensional (3D) data interactions; (iii) a non-numerical version that displays temporal data directionality (arrows that connect pairs of consecutive observations); and (iv) a full 4D (single line-, complexity-, directionality-based) version. Results In all studies, the non-structured approach revealed non-interpretable (ambiguous) data: observations numerically similar expressed different biological conditions, such as recovery and lack of recovery from infections. Ambiguity was also found when the data were structured as single lines. In contrast, two or more data subsets were distinguished and ambiguity was avoided when the data were structured as complex, 3D, single lines and, in addition, temporal data directionality was determined. The 4D method detected, even within one day, changes in immune profiles that occurred after antibiotics were prescribed. Conclusions Infectious disease data may be ambiguous. Four-dimensional methods may prevent ambiguity, providing earlier, in vivo, dynamic, complex, and

  9. Children's Understanding of Ambiguous Figures: Which Cognitive Developments Are Necessary to Experience Reversal

    ERIC Educational Resources Information Center

    Doherty, M.J.; Wimmer, M.C.

    2005-01-01

    In two experiments involving one hundred and thirty-eight 3- to 5-year-olds we examined the claim that a complex understanding of ambiguity is required to experience reversal of ambiguous stimuli [Gopnik, A., & Rosati, A. (2001). Duck or rabbit? Reversing ambiguous figures and understanding ambiguous representations. Developmental Science, 4,…

  10. Geometrical ambiguity of pair statistics. II. Heterogeneous media

    NASA Astrophysics Data System (ADS)

    Jiao, Yang; Stillinger, Frank H.; Torquato, Salvatore

    2010-07-01

    In the first part of this series of two papers [Y. Jiao, F. H. Stillinger, and S. Torquato, Phys. Rev. E 81, 011105 (2010)10.1103/PhysRevE.81.011105], we considered the geometrical ambiguity of pair statistics associated with point configurations. Here we focus on the analogous problem for heterogeneous media (materials). Heterogeneous media are ubiquitous in a host of contexts, including composites and granular media, biological tissues, ecological patterns, and astrophysical structures. The complex structures of heterogeneous media are usually characterized via statistical descriptors, such as the n -point correlation function Sn . An intricate inverse problem of practical importance is to what extent a medium can be reconstructed from the two-point correlation function S2 of a target medium. Recently, general claims of the uniqueness of reconstructions using S2 have been made based on numerical studies, which implies that S2 suffices to uniquely determine the structure of a medium within certain numerical accuracy. In this paper, we provide a systematic approach to characterize the geometrical ambiguity of S2 for both continuous two-phase heterogeneous media and their digitized representations in a mathematically precise way. In particular, we derive the exact conditions for the case where two distinct media possess identical S2 , i.e., they form a degenerate pair. The degeneracy conditions are given in terms of integral and algebraic equations for continuous media and their digitized representations, respectively. By examining these equations and constructing their rigorous solutions for specific examples, we conclusively show that in general S2 is indeed not sufficient information to uniquely determine the structure of the medium, which is consistent with the results of our recent study on heterogeneous-media reconstruction [Y. Jiao, F. H. Stillinger, and S. Torquato, Proc. Natl. Acad. Sci. U.S.A. 106, 17634 (2009)10.1073/pnas.0905919106]. The analytical

  11. Reduction of Phase Ambiguity in an Offset-QPSK Receiver

    NASA Technical Reports Server (NTRS)

    Berner, Jeff; Kinman, Peter

    2004-01-01

    Proposed modifications of an offset-quadri-phase-shift keying (offset-QPSK) transmitter and receiver would reduce the amount of signal processing that must be done in the receiver to resolve the QPSK fourfold phase ambiguity. Resolution of the phase ambiguity is necessary in order to synchronize, with the received carrier signal, the signal generated by a local oscillator in a carrier-tracking loop in the receiver. Without resolution of the fourfold phase ambiguity, the loop could lock to any of four possible phase points, only one of which has the proper phase relationship with the carrier. The proposal applies, more specifically, to an offset-QPSK receiver that contains a carrier-tracking loop like that shown in Figure 1. This carrier-tracking loop does not resolve or reduce the phase ambiguity. A carrier-tracking loop of a different design optimized for the reception of offset QPSK could reduce the phase ambiguity from fourfold to twofold, but would be more complex. Alternatively, one could resolve the fourfold phase ambiguity by use of differential coding in the transmitter, at a cost of reduced power efficiency. The proposed modifications would make it possible to reduce the fourfold phase ambiguity to twofold, with no loss in power efficiency and only relatively simple additional signal-processing steps in the transmitter and receiver. The twofold phase ambiguity would then be resolved by use of a unique synchronization word, as is commonly done in binary phase-shift keying (BPSK). Although the mathematical and signal-processing principles underlying the modifications are too complex to explain in detail here, the modifications themselves would be relatively simple and are best described with the help of simple block diagrams (see Figure 2). In the transmitter, one would add a unit that would periodically invert bits going into the QPSK modulator; in the receiver, one would add a unit that would effect different but corresponding inversions of bits coming out

  12. Auditory Scene Analysis: The Sweet Music of Ambiguity

    PubMed Central

    Pressnitzer, Daniel; Suied, Clara; Shamma, Shihab A.

    2011-01-01

    In this review paper aimed at the non-specialist, we explore the use that neuroscientists and musicians have made of perceptual illusions based on ambiguity. The pivotal issue is auditory scene analysis (ASA), or what enables us to make sense of complex acoustic mixtures in order to follow, for instance, a single melody in the midst of an orchestra. In general, ASA uncovers the most likely physical causes that account for the waveform collected at the ears. However, the acoustical problem is ill-posed and it must be solved from noisy sensory input. Recently, the neural mechanisms implicated in the transformation of ambiguous sensory information into coherent auditory scenes have been investigated using so-called bistability illusions (where an unchanging ambiguous stimulus evokes a succession of distinct percepts in the mind of the listener). After reviewing some of those studies, we turn to music, which arguably provides some of the most complex acoustic scenes that a human listener will ever encounter. Interestingly, musicians will not always aim at making each physical source intelligible, but rather express one or more melodic lines with a small or large number of instruments. By means of a few musical illustrations and by using a computational model inspired by neuro-physiological principles, we suggest that this relies on a detailed (if perhaps implicit) knowledge of the rules of ASA and of its inherent ambiguity. We then put forward the opinion that some degree perceptual ambiguity may participate in our appreciation of music. PMID:22174701

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

    SciTech Connect

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

    1991-03-01

    Some years ago, Drisko {ital et} {ital al}. suggested that the discrete ambiguity often encountered for elastic scattering optical potentials could be understood as being due to the interior or small-{ital l} {ital S}-matrix elements for two equivalent'' potentials differing in phase by 2{pi}, {ital l}-by-{ital l}. We point out that the {ital 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 {delta}{sub {ital l}}{r arrow}({delta}{sub {ital l}}+{pi}) for low-{ital l} phases relative to the high-{ital 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-{ital 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.

  14. How to Give Your Child Medicine

    MedlinePlus

    ... any questions you have about the medicine. For liquid medicines, the pharmacist should give you a measuring ... make medicine taste better to your child. Put liquid medicines in the refrigerator before giving them to ...

  15. Housing conditions affect rat responses to two types of ambiguity in a reward–reward discrimination cognitive bias task

    PubMed Central

    Parker, Richard M.A.; Paul, Elizabeth S.; Burman, Oliver H.P.; Browne, William J.; Mendl, Michael

    2014-01-01

    Decision-making under ambiguity in cognitive bias tasks is a promising new indicator of affective valence in animals. Rat studies support the hypothesis that animals in a negative affective state evaluate ambiguous cues negatively. Prior automated operant go/go judgement bias tasks have involved training rats that an auditory cue of one frequency predicts a Reward and a cue of a different frequency predicts a Punisher (RP task), and then measuring whether ambiguous cues of intermediate frequency are judged as predicting reward (‘optimism’) or punishment (‘pessimism’). We investigated whether an automated Reward–Reward (RR) task yielded similar results to, and was faster to train than, RP tasks. We also introduced a new ambiguity test (simultaneous presentation of the two training cues) alongside the standard single ambiguous cue test. Half of the rats experienced an unpredictable housing treatment (UHT) designed to induce a negative state. Control rats were relatively ‘pessimistic’, whilst UHT rats were quicker, but no less accurate, in their responses in the RR test, and showed less anxiety-like behaviour in independent tests. A possible reason for these findings is that rats adapted to and were stimulated by UHT, whilst control rats in a predictable environment were more sensitive to novelty and change. Responses in the new ambiguity test correlated positively with those in single ambiguous cue tests, and may provide a measure of attention bias. The RR task was quicker to train than previous automated RP tasks. Together, they could be used to disentangle how reward and punishment processes underpin affect-induced cognitive biases. PMID:25106739

  16. Housing conditions affect rat responses to two types of ambiguity in a reward-reward discrimination cognitive bias task.

    PubMed

    Parker, Richard M A; Paul, Elizabeth S; Burman, Oliver H P; Browne, William J; Mendl, Michael

    2014-11-01

    Decision-making under ambiguity in cognitive bias tasks is a promising new indicator of affective valence in animals. Rat studies support the hypothesis that animals in a negative affective state evaluate ambiguous cues negatively. Prior automated operant go/go judgement bias tasks have involved training rats that an auditory cue of one frequency predicts a Reward and a cue of a different frequency predicts a Punisher (RP task), and then measuring whether ambiguous cues of intermediate frequency are judged as predicting reward ('optimism') or punishment ('pessimism'). We investigated whether an automated Reward-Reward (RR) task yielded similar results to, and was faster to train than, RP tasks. We also introduced a new ambiguity test (simultaneous presentation of the two training cues) alongside the standard single ambiguous cue test. Half of the rats experienced an unpredictable housing treatment (UHT) designed to induce a negative state. Control rats were relatively 'pessimistic', whilst UHT rats were quicker, but no less accurate, in their responses in the RR test, and showed less anxiety-like behaviour in independent tests. A possible reason for these findings is that rats adapted to and were stimulated by UHT, whilst control rats in a predictable environment were more sensitive to novelty and change. Responses in the new ambiguity test correlated positively with those in single ambiguous cue tests, and may provide a measure of attention bias. The RR task was quicker to train than previous automated RP tasks. Together, they could be used to disentangle how reward and punishment processes underpin affect-induced cognitive biases.

  17. Housing conditions affect rat responses to two types of ambiguity in a reward-reward discrimination cognitive bias task.

    PubMed

    Parker, Richard M A; Paul, Elizabeth S; Burman, Oliver H P; Browne, William J; Mendl, Michael

    2014-11-01

    Decision-making under ambiguity in cognitive bias tasks is a promising new indicator of affective valence in animals. Rat studies support the hypothesis that animals in a negative affective state evaluate ambiguous cues negatively. Prior automated operant go/go judgement bias tasks have involved training rats that an auditory cue of one frequency predicts a Reward and a cue of a different frequency predicts a Punisher (RP task), and then measuring whether ambiguous cues of intermediate frequency are judged as predicting reward ('optimism') or punishment ('pessimism'). We investigated whether an automated Reward-Reward (RR) task yielded similar results to, and was faster to train than, RP tasks. We also introduced a new ambiguity test (simultaneous presentation of the two training cues) alongside the standard single ambiguous cue test. Half of the rats experienced an unpredictable housing treatment (UHT) designed to induce a negative state. Control rats were relatively 'pessimistic', whilst UHT rats were quicker, but no less accurate, in their responses in the RR test, and showed less anxiety-like behaviour in independent tests. A possible reason for these findings is that rats adapted to and were stimulated by UHT, whilst control rats in a predictable environment were more sensitive to novelty and change. Responses in the new ambiguity test correlated positively with those in single ambiguous cue tests, and may provide a measure of attention bias. The RR task was quicker to train than previous automated RP tasks. Together, they could be used to disentangle how reward and punishment processes underpin affect-induced cognitive biases. PMID:25106739

  18. Income Tax Policy and Charitable Giving

    ERIC Educational Resources Information Center

    Brooks, Arthur C.

    2007-01-01

    Many studies over the past 20 years have looked at the response of charitable donations to tax incentives--the tax price elasticity of giving. Generally, authors have assumed this elasticity is constant across all types of giving. Using the 2001 Panel Study of Income Dynamics data on charitable giving, this paper estimates the tax price elasticity…

  19. Assumptions and ambiguities in nonplanar acoustic soliton theory

    SciTech Connect

    Verheest, Frank; Hellberg, Manfred A.

    2014-02-15

    There have been many recent theoretical investigations of the nonlinear evolution of electrostatic modes with cylindrical or spherical symmetry. Through a reductive perturbation analysis based on a quasiplanar stretching, a modified form of the Korteweg-de Vries or related equation is derived, containing an additional term which is linear in the electrostatic potential and singular at time t = 0. Unfortunately, these analyses contain several restrictive assumptions and ambiguities which are normally neither properly explained nor discussed, and severely limit the applicability of the technique. Most glaring are the use of plane-wave stretchings, the assumption that shape-preserving cylindrical modes can exist and that, although time is homogeneous, the origin of time (which can be chosen arbitrarily) needs to be avoided. Hence, only in the domain where the nonlinear modes are quasiplanar, far from the axis of cylindrical or from the origin of spherical symmetry can acceptable but unexciting results be obtained. Nonplanar nonlinear modes are clearly an interesting topic of research, as some of these phenomena have been observed in experiments. However, it is argued that a proper study of such modes needs numerical simulations rather than ill-suited analytical approximations.

  20. Domain-specific genetic influence on visual-ambiguity resolution.

    PubMed

    Wang, Ying; Wang, Li; Xu, Qian; Liu, Dong; Jiang, Yi

    2014-08-01

    The visual world is flooded with ambiguity. Generally, people can resolve the ambiguity almost instantaneously, as when they distinguish at a glance whether a maiden in a portrait by Picasso is in profile or facing front. However, perception of the same reality, though relatively stable at the individual level, can vary dramatically from person to person, manifesting idiosyncratic perceptual biases. What drives the heterogeneity of human vision as reflected in the resolution of visual ambiguity? Using the twin method, we demonstrated a significant genetic contribution to individual differences in the visual disambiguation of bistable biological-motion stimuli but not inanimate motion stimuli. These findings challenge the prevailing view that the way the human brain makes sense of visual input is largely shaped by a person's perceptual history. Rather, the visual perception of biologically salient information can be guided by adaptive mental "priors" that are genetically transmitted. PMID:24914030

  1. Ambiguity of structure determination from a minimum of diffraction intensities.

    PubMed

    Al-Asadi, Ahmed; Leggas, Dimitri; Tsodikov, Oleg V

    2014-07-01

    Although the ambiguity of the crystal structures determined directly from diffraction intensities has been historically recognized, it is not well understood in quantitative terms. Bernstein's theorem has recently been used to obtain the number of one-dimensional crystal structures of equal point atoms, given a minimum set of diffraction intensities. By a similar approach, the number of two- and three-dimensional crystal structures that can be determined from a minimum intensity data set is estimated herein. The ambiguity of structure determination from the algebraic minimum of data increases at least exponentially fast with the increasing structure size. Substituting lower-resolution intensities by higher-resolution ones in the minimum data set has little or no effect on this ambiguity if the number of such substitutions is relatively small. PMID:25970192

  2. Neural signatures of economic preferences for risk and ambiguity.

    PubMed

    Huettel, Scott A; Stowe, C Jill; Gordon, Evan M; Warner, Brent T; Platt, Michael L

    2006-03-01

    People often prefer the known over the unknown, sometimes sacrificing potential rewards for the sake of surety. Overcoming impulsive preferences for certainty in order to exploit uncertain but potentially lucrative options may require specialized neural mechanisms. Here, we demonstrate by functional magnetic resonance imaging (fMRI) that individuals' preferences for risk (uncertainty with known probabilities) and ambiguity (uncertainty with unknown probabilities) predict brain activation associated with decision making. Activation within the lateral prefrontal cortex was predicted by ambiguity preference and was also negatively correlated with an independent clinical measure of behavioral impulsiveness, suggesting that this region implements contextual analysis and inhibits impulsive responses. In contrast, activation of the posterior parietal cortex was predicted by risk preference. Together, this novel double dissociation indicates that decision making under ambiguity does not represent a special, more complex case of risky decision making; instead, these two forms of uncertainty are supported by distinct mechanisms.

  3. Application Of Digital Image Processing To Acoustic Ambiguity Functions

    NASA Astrophysics Data System (ADS)

    Sharkey, J. Brian

    1983-03-01

    The passive acoustic ambiguity function is a measure of the cross-spectrum in a Doppler-shift and time-delay space that arises when two or more passive receivers are used to monitor a moving acoustic source. Detection of a signal source in the presence of noise has been treated in the past from a communications-theory point of view, with considerable effort devoted to establishing a threshold to which the maximum value of the function is compared. That approach disregards ambiguity function topography information which in practice is manually used to interpret source characteristics and source kinematics. Because of the two-dimensional representation of the ambiguity function, digital image processing techniques can be easily applied for the purposes of topography enhancement and characterization. This work presents an overview of techniques previously reported as well as more current research being conducted to improve detection performance and automate topography characterization.

  4. Phase ambiguity resolution for offset QPSK modulation systems

    NASA Astrophysics Data System (ADS)

    Nguyen, Tien M.

    1991-06-01

    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.

  5. Phase ambiguity resolution for offset QPSK modulation systems

    NASA Technical Reports Server (NTRS)

    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.

  6. Strategies for avoiding errors and ambiguities in the analysis of oscillatory pumping tests

    NASA Astrophysics Data System (ADS)

    Cardiff, Michael; Sayler, Claire

    2016-09-01

    Oscillatory pumping tests have recently seen a resurgence in interest as a strategy for aquifer characterization. In a cross-well pumping test, measured responses to oscillatory pumping tests consist of the amplitude and phase delay of pressure changes at an observation well. This information can be used to obtain estimates of effective aquifer parameters (conductivity and storage coefficients), by fitting field data with an analytical model through parameter estimation. Alternately, multiple pumping tests can be fit simultaneously through tomographic analyses. However, in both cases, analysis of obtained test results may be ambiguous if "phase wrapping" occurs, i.e. if signals are delayed by more than one period. In this work, we demonstrate scenarios under which phase wrapping can make analysis of oscillatory testing difficult, and present guidelines for avoiding ambiguity in oscillatory testing results.

  7. Results.

    ERIC Educational Resources Information Center

    Zemsky, Robert; Shaman, Susan; Shapiro, Daniel B.

    2001-01-01

    Describes the Collegiate Results Instrument (CRI), which measures a range of collegiate outcomes for alumni 6 years after graduation. The CRI was designed to target alumni from institutions across market segments and assess their values, abilities, work skills, occupations, and pursuit of lifelong learning. (EV)

  8. Instantaneous and controllable integer ambiguity resolution: review and an alternative approach

    NASA Astrophysics Data System (ADS)

    Zhang, Jingyu; Wu, Meiping; Li, Tao; Zhang, Kaidong

    2015-11-01

    In the high-precision application of Global Navigation Satellite System (GNSS), integer ambiguity resolution is the key step to realize precise positioning and attitude determination. As the necessary part of quality control, integer aperture (IA) ambiguity resolution provides the theoretical and practical foundation for ambiguity validation. It is mainly realized by acceptance testing. Due to the constraint of correlation between ambiguities, it is impossible to realize the controlling of failure rate according to analytical formula. Hence, the fixed failure rate approach is implemented by Monte Carlo sampling. However, due to the characteristics of Monte Carlo sampling and look-up table, we have to face the problem of a large amount of time consumption if sufficient GNSS scenarios are included in the creation of look-up table. This restricts the fixed failure rate approach to be a post process approach if a look-up table is not available. Furthermore, if not enough GNSS scenarios are considered, the table may only be valid for a specific scenario or application. Besides this, the method of creating look-up table or look-up function still needs to be designed for each specific acceptance test. To overcome these problems in determination of critical values, this contribution will propose an instantaneous and CONtrollable (iCON) IA ambiguity resolution approach for the first time. The iCON approach has the following advantages: (a) critical value of acceptance test is independently determined based on the required failure rate and GNSS model without resorting to external information such as look-up table; (b) it can be realized instantaneously for most of IA estimators which have analytical probability formulas. The stronger GNSS model, the less time consumption; (c) it provides a new viewpoint to improve the research about IA estimation. To verify these conclusions, multi-frequency and multi-GNSS simulation experiments are implemented. Those results show that IA

  9. Experimental validation of the use of Kramers-Kronig relations to eliminate the phase sheet ambiguity in broadband phase spectroscopy.

    PubMed

    Trousil, R L; Waters, K R; Miller, J G

    2001-05-01

    The technique of broadband phase spectroscopy proposed in 1978 by Sachse and Pao [J. Appl. Phys. 49, 4320-4327 (1978)] determines the phase velocity as a function of frequency from the Fourier transforms of a received reference and through-sample signal. Although quite successful, this approach can be influenced by an ambiguity in the phase velocity calculation which stems from the boundedness of the inverse tangent operation used to calculate phase. Several empirical approaches to resolve the phase ambiguity have been reported. An alternative approach that has not previously been considered appeals to the causal nature of the measurements. This article experimentally validates a method which uses the causally consistent Kramers-Kronig relations to eliminate the ambiguity in phase spectroscopy-derived phase velocity calculations. Broadband pulse and narrow-band tone burst measurements were performed on three gelatin-based phantoms containing different concentrations of graphite particles (0%, 10%, and 20% by volume). The phantoms were constructed to have attenuation coefficients which vary approximately linear-with-frequency, a dependence exhibited by many soft tissues. The narrow-band phase velocity measurements do not suffer from a phase ambiguity, and thus they serve as a "gold standard" against which the broadband phase velocity measurements are compared. The experimental results illustrate that using the Kramers-Kronig dispersion relations in conjunction with phase spectroscopy-derived phase velocity measurements is an effective means by which to resolve the phase sheet ambiguity in broadband phase spectroscopy.

  10. [Eye movement parameters in reading the sentences with syntactic ambiguity in Russian language].

    PubMed

    Anisimov, V A; Fedorova, O V; Latanov, A V

    2014-01-01

    We studied the eye movement parameters during reading of syntactically ambiguous sentences with feminine relative clause in Russian language. A priori difficulties of sentence structural analysis results in increase of time spent on reading as opposed to reading control sentences (unambiguous). Such a delay is caused by an increase of frequency of regressions (backward saccades) which are executed for rereading an ambiguous fragment ofsentence. This fact in turn leads to an increase in number of fixations and their duration. The total reading time for particular words composing the ambiguous fragment of sentence depended on disambiguation result (relative clause attachment, early/late closure). In case of early closure (when the subject attached relative clause to first noun) the total reading time for this noun exceeded one for second noun. In case of late closure (when the subject attached relative clause to second noun) the total reading time for both nouns didn't differ. Our results indicate that early closure domination in Russian language determines the greater total reading time for first noun of nominal group associated with relative clause.

  11. Assessing Ambiguity of Context Data in Intelligent Environments: Towards a More Reliable Context Managing System

    PubMed Central

    Almeida, Aitor; López-de-Ipiña, Diego

    2012-01-01

    Modeling and managing correctly the user context in Smart Environments is important to achieve robust and reliable systems. When modeling reality we must take into account its ambiguous nature. Considering the uncertainty and vagueness in context data information it is possible to attain a more precise picture of the environment, thus leading to a more accurate inference process. To achieve these goals we present an ontology that models the ambiguity in intelligent environments and a data fusion and inference process that takes advantage of that extra information to provide better results. Our system can assess the certainty of the captured measurements, discarding the unreliable ones and combining the rest into a unified vision of the current user context. It also models the vagueness of the system, combining it with the uncertainty to obtain a richer inference process. PMID:22666068

  12. Investigation of the hostile attribution bias toward ambiguous facial cues in antisocial violent offenders.

    PubMed

    Schönenberg, Michael; Jusyte, Aiste

    2014-02-01

    Aggressive individuals exhibit a strong tendency to attribute hostile intent to the behavior of others, which may lead to provocation and aggravation of socially inappropriate reactions. Limited research has investigated the hostile attribution bias in the perception of facial affect. This study examined a hostile response bias to emotionally ambiguous faces in a population of 55 incarcerated antisocial violent offenders as compared to matched control subjects. Results suggest that aggression is associated with a strong preference to interpret ambiguous stimuli containing proportions of an angry expression as hostile, while there was no evidence for a generally biased interpretation of distress cues under conditions of uncertainty. Thus, the tendency to misinterpret nonverbal cues in social interactions may at least partly underlie aggressive-impulsive behavior in susceptible individuals. PMID:23990116

  13. Do Market Incentives Crowd Out Charitable Giving?

    PubMed

    Deck, Cary; Kimbrough, Erik O

    2013-12-01

    Donations and volunteerism can be conceived as market transactions with a zero explicit price. However, evidence suggests people may not view zero as just another price when it comes to pro-social behavior. Thus, while markets might be expected to increase the supply of assets available to those in need, some worry such financial incentives will crowd out altruistic giving. This paper reports laboratory experiments directly investigating the degree to which market incentives crowd out large, discrete charitable donations in a setting related to deceased organ donation. The results suggest markets increase the supply of assets available to those in need. However, as some critics fear, market incentives disproportionately influence the relatively poor.

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

    ERIC Educational Resources Information Center

    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…

  15. Difficulty Processing Temporary Syntactic Ambiguities in Lewy Body Spectrum Disorder

    ERIC Educational Resources Information Center

    Grossman, Murray; Gross, Rachel G.; Moore, Peachie; Dreyfuss, Michael; McMillan, Corey T.; Cook, Philip A.; Ash, Sherry; Siderowf, Andrew

    2012-01-01

    While grammatical aspects of language are preserved, executive deficits are prominent in Lewy body spectrum disorder (LBSD), including Parkinson's disease (PD), Parkinson's dementia (PDD) and dementia with Lewy bodies (DLB). We examined executive control during sentence processing in LBSD by assessing temporary structural ambiguities. Using an…

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

    ERIC Educational Resources Information Center

    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.

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

    ERIC Educational Resources Information Center

    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…

  18. Range ambiguity suppression technique for the spaceborne synthetic aperture radar

    NASA Astrophysics Data System (ADS)

    Jha, A. M.; Majmudar, Archana; Pillai, N. S.

    1988-10-01

    The aim of any spaceborne Synthetic Aperture Radar (SAR) system design is to keep the range ambiguous responses as low as possible. A higher value of range ambiguity deteriorates the SAR image quality. The wider swath requirement at higher incidence angle (greater than 45 deg) deteriorates the range ambiguity ratio (RAR) and hence the image quality of SAR quite significantly. The requirement of minimum acceptable RAR even for very nominal swath at these incidence angles may necessitate larger antenna width, very complex weighting, and highly asymmetrical antenna elevation pattern. An alternate scheme is suggested in this paper to alleviate the criticality and complexity of the design aspects for such a requirement. Here, the chirp slope of the transmitted linear frequency modulated pulses is reversed alternately. Hence, during the range compression, a significant portion of the ambiguous return is suppressed due to the mismatching with the signal reference function. The proposed method provides significant improvement in RAR and can be utilized in attaining wider swath, specifically at higher incidence angles.

  19. Ambiguity, Accessibility, and a Division of Labor for Communicative Success

    PubMed Central

    Ferreira, Victor S.

    2009-01-01

    People talk to be understood, and so they should produce utterances that are easy for their listeners to understand. I begin this chapter by describing evidence showing that speakers rarely avoid sentences that are ambiguous, even though ambiguity is a factor that is well known to cause difficulty for listeners. Instead, speakers seem to choose utterances that are especially easy for them to say, specifically by producing more accessible, easy-to-think-of material sooner, and less accessible, harder-to-think-of material later. If speakers produce utterances that are easy to say but not utterances that are easy to understand, how is it that we understand each other? A third line of evidence shows that even when sentences are structurally ambiguous, they’re likely to include enough information for comprehenders to figure out what they mean. This suggests that speakers produce ambiguous utterances simply because they can -- because the grammar of their language will only let them produce utterances that are unambiguous enough to be understood most of the time anyway. And so, we understand each other because speakers produce utterances efficiently even if they’re not optimally understandable; addressees do what they need to to understand their speakers; and the grammar makes sure everything works out properly. PMID:19710948

  20. Expecting and Accepting: The Temporal Ambiguity of Recovery Identities

    ERIC Educational Resources Information Center

    Howard, Jenna

    2006-01-01

    This paper has two complementary agendas. One is to develop a formal analysis of temporal ambiguity in self-identification. This refers specifically to having two conflicting orientations toward the future with regard to one's identity (e.g., a temporary expecting orientation and a permanent accepting orientation). I use the recovery identity…

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

    ERIC Educational Resources Information Center

    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…

  2. Phrase Length and Prosody in On-Line Ambiguity Resolution

    ERIC Educational Resources Information Center

    Webman-Shafran, Ronit; Fodor, Janet Dean

    2016-01-01

    We investigated the processing of ambiguous double-PP constructions in Hebrew. Selection restrictions forced the first prepositional phrase (PP1) to attach low, but PP2 could attach maximally high to VP or maximally low to the NP inside PP1. A length contrast in PP2 was also examined. This construction affords more potential locations for prosodic…

  3. Children's Use of Gesture in Ambiguous Pronoun Interpretation

    ERIC Educational Resources Information Center

    Goodrich Smith, Whitney; Hudson Kam, Carla L.

    2015-01-01

    This study explores whether children can use gesture to inform their interpretation of ambiguous pronouns. Specifically, we ask whether four- to eight-year-old English-speaking children are sensitive to information contained in co-referential localizing gestures in video narrations. The data show that the older (7-8 years of age) but not younger…

  4. Sublexical Ambiguity Effect in Reading Chinese Disyllabic Compounds

    ERIC Educational Resources Information Center

    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…

  5. Effect of Semantic Constraints on Processing Ambiguous Words.

    ERIC Educational Resources Information Center

    Hartman, David E.

    Native English speakers performed a phoneme-monitoring task to assess whether ambiguous words (homographs) require extra processing capacity under two conditions: no prior context and prior context provided by disambiguating subject-noun and verb combinations. Phoneme detection latencies were reliably longer for homographs than for control words…

  6. The Development of Preschoolers' Appreciation of Communicative Ambiguity

    ERIC Educational Resources Information Center

    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…

  7. Prosody and the Interpretation of Hierarchically Ambiguous Discourse

    ERIC Educational Resources Information Center

    Tyler, Joseph

    2014-01-01

    Although significant attention has been devoted to prosody in discourse production, relatively little is known about prosody's effect on discourse interpretation. This article explores the ability of synthetic manipulations of prosody to bias interpretation of discourse ambiguities where a first sentence is linked to two following sentences…

  8. Bidirectional Transfer: Consequences of Translation Ambiguity for Bilingual Word Meaning

    ERIC Educational Resources Information Center

    Degani, Tamar

    2011-01-01

    Could a second language (L2) influence how bilinguals process their native language (L1)? The work described in this dissertation examined this issue focusing on the way bilinguals interpret the meanings of words. Capitalizing on the prevalence of words that can be translated in more than one way across languages (i.e., "translation ambiguity,"…

  9. Ambiguity of Visual Design and Meaning in TV's "Battlestar Galactica."

    ERIC Educational Resources Information Center

    Roth, Lane

    "Battlestar Galactica," ABC-TV's prime-time science fiction series for 1978-79, illustrates how popular, mass media entertainment can communicate contradictory meanings that correlate with unresolved cultural tensions. The ambiguity of visual design is especially confusing because it is contrapuntal to the simplicity and clarity of the formulaic…

  10. Absence of Real Evidence against Competition during Syntactic Ambiguity Resolution

    ERIC Educational Resources Information Center

    Green, Matthew J.; Mitchell, Don C.

    2006-01-01

    Using evidence from eye-tracking studies, Van Gompel, Pickering, Pearson, and Liversedge (2005) have argued against currently implemented constraint-based models of syntactic ambiguity resolution. The case against these competition models is based on a mismatch between reported patterns of reading data and the putative predictions of the models.…

  11. What Is Reflection? Looking for Clarity in an Ambiguous Notion

    ERIC Educational Resources Information Center

    Clarà, Marc

    2015-01-01

    The notion of reflection nowadays is considered crucial in the field of teaching and teacher education. However, although the great majority of approaches to reflection are grounded on the same main theoretical sources, the meaning of this notion is unanimously recognized in the field to be ambiguous. This article aims to look for clarity about…

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

    ERIC Educational Resources Information Center

    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…

  13. Reading as Reasoning; Reading as Ambiguity: Understanding Sentence Structures.

    ERIC Educational Resources Information Center

    Marcus, Albert

    If in reading a sentence a reader finds something unfamiliar in lexical meaning or grammatical structures, the meaning of the written material may be ambiguous to him. Sometimes the context will help to clarify the meaning of an unfamiliar element, but often it won't. Understanding what is read involves not only the process of reasoning, but also…

  14. Target Tracking Using SePDAF under Ambiguous Angles for Distributed Array Radar.

    PubMed

    Long, Teng; Zhang, Honggang; Zeng, Tao; Chen, Xinliang; Liu, Quanhua; Zheng, Le

    2016-09-09

    Distributed array radar can improve radar detection capability and measurement accuracy. However, it will suffer cyclic ambiguity in its angle estimates according to the spatial Nyquist sampling theorem since the large sparse array is undersampling. Consequently, the state estimation accuracy and track validity probability degrades when the ambiguous angles are directly used for target tracking. This paper proposes a second probability data association filter (SePDAF)-based tracking method for distributed array radar. Firstly, the target motion model and radar measurement model is built. Secondly, the fusion result of each radar's estimation is employed to the extended Kalman filter (EKF) to finish the first filtering. Thirdly, taking this result as prior knowledge, and associating with the array-processed ambiguous angles, the SePDAF is applied to accomplish the second filtering, and then achieving a high accuracy and stable trajectory with relatively low computational complexity. Moreover, the azimuth filtering accuracy will be promoted dramatically and the position filtering accuracy will also improve. Finally, simulations illustrate the effectiveness of the proposed method.

  15. Acute stress eliminates female advantage in detection of ambiguous negative affect.

    PubMed

    DeDora, Daniel J; Carlson, Joshua M; Mujica-Parodi, Lilianne R

    2011-11-15

    The human stress response evolved to maximize an individual's probability of survival when threatened. The present study addressed whether physical danger modulates perception of an unrelated ambiguous threat and, if so, to what extent this response is sex- specific. The authors utilized a first-time tandem skydive as a stressor, which had been previously validated as producing a highly-controlled, genuinely stressful environment. In a counter-balanced within-subjects design, participants wore a virtual reality helmet to complete an emotion-identification task during the plane's ascent (stress condition) and in the laboratory (control condition). Participants were presented static male faces morphed between 20-80% aggression, which gradually emerged from degraded images. Using a binary forced-choice design, participants identified each ambiguous face as aggressive or neutral. Results showed that participants characterized emotion more rapidly under stress versus control conditions. Unexpectedly, the results also show that while women were more sensitive to affect ambiguity than men under control conditions, they exhibited a marked decrease in sensitivity equivalent to men while under stress.

  16. Target Tracking Using SePDAF under Ambiguous Angles for Distributed Array Radar.

    PubMed

    Long, Teng; Zhang, Honggang; Zeng, Tao; Chen, Xinliang; Liu, Quanhua; Zheng, Le

    2016-01-01

    Distributed array radar can improve radar detection capability and measurement accuracy. However, it will suffer cyclic ambiguity in its angle estimates according to the spatial Nyquist sampling theorem since the large sparse array is undersampling. Consequently, the state estimation accuracy and track validity probability degrades when the ambiguous angles are directly used for target tracking. This paper proposes a second probability data association filter (SePDAF)-based tracking method for distributed array radar. Firstly, the target motion model and radar measurement model is built. Secondly, the fusion result of each radar's estimation is employed to the extended Kalman filter (EKF) to finish the first filtering. Thirdly, taking this result as prior knowledge, and associating with the array-processed ambiguous angles, the SePDAF is applied to accomplish the second filtering, and then achieving a high accuracy and stable trajectory with relatively low computational complexity. Moreover, the azimuth filtering accuracy will be promoted dramatically and the position filtering accuracy will also improve. Finally, simulations illustrate the effectiveness of the proposed method. PMID:27618058

  17. Rotation Matrix Method Based on Ambiguity Function for GNSS Attitude Determination.

    PubMed

    Yang, Yingdong; Mao, Xuchu; Tian, Weifeng

    2016-06-08

    Global navigation satellite systems (GNSS) are well suited for attitude determination. In this study, we use the rotation matrix method to resolve the attitude angle. This method achieves better performance in reducing computational complexity and selecting satellites. The condition of the baseline length is combined with the ambiguity function method (AFM) to search for integer ambiguity, and it is validated in reducing the span of candidates. The noise error is always the key factor to the success rate. It is closely related to the satellite geometry model. In contrast to the AFM, the LAMBDA (Least-squares AMBiguity Decorrelation Adjustment) method gets better results in solving the relationship of the geometric model and the noise error. Although the AFM is more flexible, it is lack of analysis on this aspect. In this study, the influence of the satellite geometry model on the success rate is analyzed in detail. The computation error and the noise error are effectively treated. Not only is the flexibility of the AFM inherited, but the success rate is also increased. An experiment is conducted in a selected campus, and the performance is proved to be effective. Our results are based on simulated and real-time GNSS data and are applied on single-frequency processing, which is known as one of the challenging case of GNSS attitude determination.

  18. Perceiving racism in ambiguous situations: who relies on easy-to-use information?

    PubMed

    Corning, Alexandra F; Bucchianeri, Michaela M

    2010-01-01

    In situations that are ambiguous with regard to the presence of discrimination, how do people arrive at their conclusions that discrimination has (or has not) taken place? This question was examined from a motivated social cognition perspective via the interaction of two factors: the prototype effect--the notion that ambiguously discriminatory behavior is more likely to be perceived as discriminatory when the executor is prototypical and the need for cognitive closure--the tendency to jump hastily to and seize on an answer. Results provided replicating evidence of the prototype effect among European American participants but not among African American participants. Specifically, European Americans were likely to perceive ambiguously racist behavior enacted by a prototypical executor (i.e., a White person) as more discriminatory than the same behavior exhibited by a non-prototypical executor (i.e., a Black person). African American participants, on the other hand, showed no reliance on this simple cognitive heuristic. Furthermore, results showed that European Americans with a higher need for cognitive closure were more likely to rely on the easy-to-use information offered by prototypes. These findings are discussed from a motivated social cognition perspective.

  19. Rotation Matrix Method Based on Ambiguity Function for GNSS Attitude Determination

    PubMed Central

    Yang, Yingdong; Mao, Xuchu; Tian, Weifeng

    2016-01-01

    Global navigation satellite systems (GNSS) are well suited for attitude determination. In this study, we use the rotation matrix method to resolve the attitude angle. This method achieves better performance in reducing computational complexity and selecting satellites. The condition of the baseline length is combined with the ambiguity function method (AFM) to search for integer ambiguity, and it is validated in reducing the span of candidates. The noise error is always the key factor to the success rate. It is closely related to the satellite geometry model. In contrast to the AFM, the LAMBDA (Least-squares AMBiguity Decorrelation Adjustment) method gets better results in solving the relationship of the geometric model and the noise error. Although the AFM is more flexible, it is lack of analysis on this aspect. In this study, the influence of the satellite geometry model on the success rate is analyzed in detail. The computation error and the noise error are effectively treated. Not only is the flexibility of the AFM inherited, but the success rate is also increased. An experiment is conducted in a selected campus, and the performance is proved to be effective. Our results are based on simulated and real-time GNSS data and are applied on single-frequency processing, which is known as one of the challenging case of GNSS attitude determination. PMID:27338390

  20. Target Tracking Using SePDAF under Ambiguous Angles for Distributed Array Radar

    PubMed Central

    Long, Teng; Zhang, Honggang; Zeng, Tao; Chen, Xinliang; Liu, Quanhua; Zheng, Le

    2016-01-01

    Distributed array radar can improve radar detection capability and measurement accuracy. However, it will suffer cyclic ambiguity in its angle estimates according to the spatial Nyquist sampling theorem since the large sparse array is undersampling. Consequently, the state estimation accuracy and track validity probability degrades when the ambiguous angles are directly used for target tracking. This paper proposes a second probability data association filter (SePDAF)-based tracking method for distributed array radar. Firstly, the target motion model and radar measurement model is built. Secondly, the fusion result of each radar’s estimation is employed to the extended Kalman filter (EKF) to finish the first filtering. Thirdly, taking this result as prior knowledge, and associating with the array-processed ambiguous angles, the SePDAF is applied to accomplish the second filtering, and then achieving a high accuracy and stable trajectory with relatively low computational complexity. Moreover, the azimuth filtering accuracy will be promoted dramatically and the position filtering accuracy will also improve. Finally, simulations illustrate the effectiveness of the proposed method. PMID:27618058

  1. Rotation Matrix Method Based on Ambiguity Function for GNSS Attitude Determination.

    PubMed

    Yang, Yingdong; Mao, Xuchu; Tian, Weifeng

    2016-01-01

    Global navigation satellite systems (GNSS) are well suited for attitude determination. In this study, we use the rotation matrix method to resolve the attitude angle. This method achieves better performance in reducing computational complexity and selecting satellites. The condition of the baseline length is combined with the ambiguity function method (AFM) to search for integer ambiguity, and it is validated in reducing the span of candidates. The noise error is always the key factor to the success rate. It is closely related to the satellite geometry model. In contrast to the AFM, the LAMBDA (Least-squares AMBiguity Decorrelation Adjustment) method gets better results in solving the relationship of the geometric model and the noise error. Although the AFM is more flexible, it is lack of analysis on this aspect. In this study, the influence of the satellite geometry model on the success rate is analyzed in detail. The computation error and the noise error are effectively treated. Not only is the flexibility of the AFM inherited, but the success rate is also increased. An experiment is conducted in a selected campus, and the performance is proved to be effective. Our results are based on simulated and real-time GNSS data and are applied on single-frequency processing, which is known as one of the challenging case of GNSS attitude determination. PMID:27338390

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

    PubMed

    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.

  3. Ambiguities in Bandt-Pompe’s methodology for local entropic quantifiers

    NASA Astrophysics Data System (ADS)

    Olivares, Felipe; Plastino, Angelo; Rosso, Osvaldo A.

    2012-04-01

    The Bandt-Pompe (BP) prescription for building up probability densities [C. Bandt, B. Pompe, Permutation entropy: a natural complexity measure for time series, Phys. Rev. Lett. 88 (2002) 174102] constituted a significant advance in the treatment of time-series. However, as we show here, ambiguities arise in applying the BP technique with reference to the permutation of ordinal patterns. This happens if one wishes to employ the BP-probability density to construct local entropic quantifiers that would characterize time-series generated by nonlinear dynamical systems. Explicit evidence of this fact is presented by comparing two different procedures, frequently found in the literature, that generate sequences of ordinal patterns. In opposition to the case of global quantifiers in the orthodox Shannon fashion, the proper order of the pertinent symbols turns out to be not uniquely predetermined for local entropic indicators. We advance the idea of employing the Fisher-Shannon information plane as a tool to resolve the ambiguity and give illustrative examples.

  4. Lived Experiences of Iranian Nurses Caring for Brain Death Organ Donor Patients: Caring as “Halo of Ambiguity and Doubt”

    PubMed Central

    Keshtkaran, Zahra; Sharif, Farkhondeh; Navab, Elham; Gholamzadeh, Sakineh

    2016-01-01

    Background: Brain death is a concept in which its criteria have been expressed as documentations in Harvard Committee of Brain Death. The various perceptions of caregiver nurses for brain death patients may have effect on the chance of converting potential donors into actual organ donors. Objective: The present study has been conducted in order to perceive the experiences of nurses in care-giving to the brain death of organ donor patients. Methods: This qualitative study was carried out by means of Heidegger’s hermeneutic phenomenology. Eight nurses who have been working in ICU were interviewed. The semi-structured interviews were recorded by a tape-recorder and the given texts were transcribed and the analyses were done by Van-Mannen methodology and (thematic) analysis. Results: One of the foremost themes extracted from this study included ‘Halo of ambiguity and doubt’ that comprised of two sub-themes of ‘having unreasonable hope’ and ‘Conservative acceptance of brain death’. The unreasonable hope included lack of trust (uncertainty) in diagnosis and verification of brain death, passing through denial wall, and avoidance from explicit and direct disclosure of brain death in patients’ family. In this investigation, the nurses were involved in a type of ambiguity and doubt in care-giving to the potentially brain death of organ donor patients, which were also evident in their interaction with patients’ family and for this reason, they did not definitely announce the brain death and so far they hoped for treatment of the given patient. Such confusion and hesitance both caused annoyance of nurses and strengthening the denial of patients’ family to be exposed to death. Conclusion: The results of this study reveal the fundamental perceived care-giving of brain death in organ donor patients and led to developing some strategies to improve care-giving and achievement in donation of the given organ and necessity for presentation of educational and

  5. Biological nomenclatures: a source of lexical knowledge and ambiguity.

    PubMed

    Tuason, O; Chen, L; Liu, H; Blake, J A; Friedman, C

    2004-01-01

    There has been increased work in developing automated systems that involve natural language processing (NLP) to recognize and extract genomic information from the literature. Recognition and identification of biological entities is a critical step in this process. NLP systems generally rely on nomenclatures and ontological specifications as resources for determining the names of the entities, assigning semantic categories that are consistent with the corresponding ontology, and assignment of identifiers that map to well-defined entities within a particular nomenclature. Although nomenclatures and ontologies are valuable for text processing systems, they were developed to aid researchers and are heterogeneous in structure and semantics. A uniform resource that is automatically generated from diverse resources, and that is designed for NLP purposes would be a useful tool for the field, and would further database interoperability. This paper presents work towards this goal. We have automatically created lexical resources from four model organism nomenclature systems (mouse, fly, worm, and yeast), and have studied performance of the resources within an existing NLP system, GENIES. Using nomenclatures is not straightforward because issues concerning ambiguity, synonymy, and name variations are quite challenging. In this paper we focus mainly on ambiguity. We determined that the number of ambiguous gene names within the individual nomenclatures, across the four nomenclatures, and with general English ranged from 0%-10.18%, 1.187%-20.30%, and 0%-2.49% respectively. When actually processing text, we found the rate of ambiguous occurrences (not counting ambiguities stemming from English words) to range from 2.4%-32.9% depending on the organisms considered.

  6. Processing ambiguity in a linguistic context: decision-making difficulties in non-aphasic patients with behavioral variant frontotemporal degeneration

    PubMed Central

    Spotorno, Nicola; Healey, Meghan; McMillan, Corey T.; Rascovsky, Katya; Irwin, David J.; Clark, Robin; Grossman, Murray

    2015-01-01

    Some extent of ambiguity is ubiquitous in everyday conversations. For example, words have multiple meaning and very common pronouns, like “he” and “she” (anaphoric pronouns), have little meaning on their own and refer to a noun that has been previously introduced in the discourse. Ambiguity triggers a decision process that is not a subroutine of language processing but rather a more general domain resource. Therefore non-aphasic patients with limited decision-making capability can encounter severe limitation in language processing due to extra linguistic limitations. In the present study, we test patients with behavioral variant frontotemporal degeneration (bvFTD), focusing on anaphora as a paradigmatic example of ambiguity resolution in the linguistic domain. bvFTD is characterized by gray matter (GM) atrophy in prefrontal cortex, but relative sparing of peri-Sylvian cortex. A group of patients with parietal disease due to corticobasal syndrome (CBS) was also tested here in order to investigate the specific role of prefrontal cortex in the task employed in the current study. Participants were presented with a pair of sentences in which the first sentence contained two nouns while the second contained a pronoun. In the experimental (ambiguous) condition, both nouns are plausible referents of the pronoun, thus requiring decision-making resources. The results revealed that bvFTD patients are significantly less accurate than healthy seniors in identifying the correct referent of a pronoun in the ambiguous condition, although CBS patients were as accurate as healthy seniors. Imaging analyses related bvFTD patients’ performance to GM atrophy in ventromedial prefrontal cortex (vmPFC). These results suggest that bvFTD patients have difficulties in decision processes that involve the resolution of an ambiguity. PMID:26578928

  7. Resolving phase ambiguities in the calibration of redundant interferometric arrays: implications for array design

    NASA Astrophysics Data System (ADS)

    Kurien, Binoy G.; Tarokh, Vahid; Rachlin, Yaron; Shah, Vinay N.; Ashcom, Jonathan B.

    2016-10-01

    We provide new results enabling robust interferometric image reconstruction in the presence of unknown aperture piston variation via the technique of redundant spacing calibration (RSC). The RSC technique uses redundant measurements of the same interferometric baseline with different pairs of apertures to reveal the piston variation among these pairs. In both optical and radio interferometry, the presence of phase-wrapping ambiguities in the measurements is a fundamental issue that needs to be addressed for reliable image reconstruction. In this paper, we show that these ambiguities affect recently developed RSC phasor-based reconstruction approaches operating on the complex visibilities, as well as traditional phase-based approaches operating on their logarithm. We also derive new sufficient conditions for an interferometric array to be immune to these ambiguities in the sense that their effect can be rendered benign in image reconstruction. This property, which we call wrap-invariance, has implications for the reliability of imaging via classical three-baseline phase closures as well as generalized closures. We show that wrap-invariance is conferred upon arrays whose interferometric graph satisfies a certain cycle-free condition. For cases in which this condition is not satisfied, a simple algorithm is provided for identifying those graph cycles which prevent its satisfaction. We apply this algorithm to diagnose and correct a member of a pattern family popular in the literature.

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

    PubMed

    Groch, Sabine; McMakin, Dana; Guggenbühl, Patrick; Rasch, Björn; Huber, Reto; Wilhelm, Ines

    2016-02-01

    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. PMID:26588358

  9. Secondary traumatization of partners of war veterans: The role of boundary ambiguity.

    PubMed

    Dekel, Rachel; Levinstein, Yoav; Siegel, Alana; Fridkin, Shimon; Svetlitzky, Vlad

    2016-02-01

    The existing literature has shown that war veterans' posttraumatic stress disorder (PTSD) symptoms are associated with a higher level of distress in their female partners. However, less agreement exists regarding the sources of this distress and the mechanism by which this process occurs. The current study examined the consequences of Israeli war veterans' PTSD on their female partners, as manifested by the females' PTSD symptoms, mental health status, and functioning, while taking into account females' earlier traumatic events. Using the theory of ambiguous loss, it also suggested boundary ambiguity as a mediating variable by which the PTSD of the male veteran is transmitted to his female partner. Participants were 300 men who had served in the 2006 Israel-Lebanon War and their female partners. Results revealed direct associations between males' PTSD and their female partners' PTSD, functioning, and mental health. In addition, boundary ambiguity mediated the association between males' PTSD and females' adjustment. Finally, females' own earlier traumatic events were directly associated with their own PTSD symptoms. Implications of this model for intervention and research are further discussed.

  10. Anisotropy in an ambiguous kinetic depth effect

    NASA Technical Reports Server (NTRS)

    Mulligan, Jeffrey B.

    1992-01-01

    A set of animated stimuli (Lissajous figures), each element of which is physically consistent with two different 3D shapes undergoing rigid rotations about orthogonal axes is presented. Predictions of which shape will be seen are made by utilizing an adaptation of Hildreth's smoothest-velocity-field computation. Results indicate that the ambiquity in 2D visual motion, i.e., the aperture problem, is not resolved before the interpretation of the 3D structure.

  11. Ambiguity produces attention shifts in category learning.

    PubMed

    Vadillo, Miguel A; Orgaz, Cristina; Luque, David; Nelson, James Byron

    2016-04-01

    It has been suggested that people and nonhuman animals protect their knowledge from interference by shifting attention toward the context when presented with information that contradicts their previous beliefs. Despite that suggestion, no studies have directly measured changes in attention while participants are exposed to an interference treatment. In the present experiments, we adapted a dot-probe task to track participants' attention to cues and contexts while they were completing a simple category learning task. The results support the hypothesis that interference produces a change in the allocation of attention to cues and contexts. PMID:26980780

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

    PubMed

    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. PMID:24992291

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

    PubMed Central

    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

  14. Kurt Gottschaldt's ambiguous relationship with national socialism.

    PubMed

    Mastroianni, George R

    2006-02-01

    Kurt Gottschaldt (1902-1991) was active in psychological research in Germany throughout much of the past century. His best-known contributions relate to three "twin camps" he ran in the late 1930s. These twin camps were designed help assess the relative contributions of heredity and environment in determining the development of psychological attributes and behavior. Gottschaldt's conclusions favored a hereditarian interpretation of his results, and Gottschaldt promoted the relevance of his twin research to "race psychology." Although Gottschaldt is sometimes described as a defender of scientific objectivity who maintained independence from Nazi ideology during the National Socialist era, some of his work suggests that a modest revision of this view may be required.

  15. Body surface area formulae: an alarming ambiguity.

    PubMed

    Redlarski, Grzegorz; Palkowski, Aleksander; Krawczuk, Marek

    2016-01-01

    Body surface area (BSA) plays a key role in several medical fields, including cancer chemotherapy, transplantology, burn treatment and toxicology. BSA is often a major factor in the determination of the course of treatment and drug dosage. A series of formulae to simplify the process have been developed. Because easy-to-identify, yet general, body coefficient results of those formulae vary considerably, the question arises as to whether the choice of a particular formula is valid and safe for patients. Here we show that discrepancies between most of the known BSA formulae can reach 0.5 m(2) for the standard adult physique. Although many previous studies have demonstrated that certain BSA formulae provide an almost exact fit with the patients examined, all of these studies have been performed on a limited and isolated group of people. Our analysis presents a broader perspective, considering 25 BSA formulae. The analysis revealed that the choice of a particular formula is a difficult task. Differences among calculations made by the formulae are so great that, in certain cases, they may considerably affect patients' mortality, especially for people with an abnormal physique or for children. PMID:27323883

  16. Thrombin–aptamer recognition: a revealed ambiguity

    PubMed Central

    Russo Krauss, Irene; Merlino, Antonello; Giancola, Concetta; Randazzo, Antonio; Mazzarella, Lelio; Sica, Filomena

    2011-01-01

    Aptamers are structured oligonucleotides that recognize molecular targets and can function as direct protein inhibitors. The best-known example is the thrombin-binding aptamer, TBA, a single-stranded 15-mer DNA that inhibits the activity of thrombin, the key enzyme of coagulation cascade. TBA folds as a G-quadruplex structure, as proved by its NMR structure. The X-ray structure of the complex between TBA and human α-thrombin was solved at 2.9-Å resolution, but did not provide details of the aptamer conformation and the interactions with the protein molecule. TBA is rapidly processed by nucleases. To improve the properties of TBA, a number of modified analogs have been produced. In particular, a modified TBA containing a 5′-5′ polarity inversion site, mTBA, has higher stability and higher affinity toward thrombin with respect to TBA, although it has a lower inhibitory activity. We present the crystal structure of the thrombin–mTBA complex at 2.15-Å resolution; the resulting model eventually provides a clear picture of thrombin–aptamers interaction, and also highlights the structural bases of the different properties of TBA and mTBA. Our findings open the way for a rational design of modified aptamers with improved potency as anticoagulant drugs. PMID:21715374

  17. Cesare Lombroso: Methodological ambiguities and brilliant intuitions.

    PubMed

    Gatti, Uberto; Verde, Alfredo

    2012-01-01

    This paper on Cesare Lombroso aims to assess his contribution to the criminological sciences. Although much praised worldwide, Lombroso was also the target of scathing criticism and unmitigated condemnation. Examination of Lombroso's method of data collection and analysis reveals his weakness. Indeed, his approach was extremely naive, simplistic and uncritical, aimed at irrefutably demonstrating the hypotheses that he championed, without exercising the methodological caution that was already beginning to characterize scientific research in his day. However, we must acknowledge that his biological theories of crime are undergoing new developments as a result of the recent success of biological psychiatry. On the other hand we should recognize that his work was not limited to his biological central theory; rather, it covered a range of cues and concepts, for the most part ignored, that demonstrate his interest in the economic, cultural and social factors that impact on crime. For these reasons, Lombroso appears to have anticipated many modern conceptions regarding delinquent behavior and criminal justice, such as those of restorative justice, the so-called "situational" theories of criminal behavior and white collar crime.

  18. Body surface area formulae: an alarming ambiguity

    PubMed Central

    Redlarski, Grzegorz; Palkowski, Aleksander; Krawczuk, Marek

    2016-01-01

    Body surface area (BSA) plays a key role in several medical fields, including cancer chemotherapy, transplantology, burn treatment and toxicology. BSA is often a major factor in the determination of the course of treatment and drug dosage. A series of formulae to simplify the process have been developed. Because easy-to-identify, yet general, body coefficient results of those formulae vary considerably, the question arises as to whether the choice of a particular formula is valid and safe for patients. Here we show that discrepancies between most of the known BSA formulae can reach 0.5 m2 for the standard adult physique. Although many previous studies have demonstrated that certain BSA formulae provide an almost exact fit with the patients examined, all of these studies have been performed on a limited and isolated group of people. Our analysis presents a broader perspective, considering 25 BSA formulae. The analysis revealed that the choice of a particular formula is a difficult task. Differences among calculations made by the formulae are so great that, in certain cases, they may considerably affect patients’ mortality, especially for people with an abnormal physique or for children. PMID:27323883

  19. Brain responses to nouns, verbs and class-ambiguous words in context.

    PubMed

    Federmeier, K D; Segal, J B; Lombrozo, T; Kutas, M

    2000-12-01

    Recent neuropsychological and imaging data have implicated different brain networks in the processing of different word classes, nouns being linked primarily to posterior, visual object-processing regions and verbs to frontal, motor-processing areas. However, as most of these studies have examined words in isolation, the consequences of such anatomically based representational differences, if any, for the processing of these items in sentences remains unclear. Additionally, in some languages many words (e.g. 'drink') are class-ambiguous, i.e. they can play either role depending on context, and it is not yet known how the brain stores and uses information associated with such lexical items in context. We examined these issues by recording event-related potentials (ERPs) in response to unambiguous nouns (e.g. 'beer'), unambiguous verbs (e. g. 'eat'), class-ambiguous words and pseudowords used as nouns or verbs within two types of minimally contrastive sentence contexts: noun-predicting (e.g. 'John wanted THE [target] but.') and verb-predicting ('John wanted TO [target] but.'). Our results indicate that the nature of neural processing for nouns and verbs is a function of both the type of stimulus and the role it is playing. Even when the context completely specifies their role, word class-ambiguous items differ from unambiguous ones over frontal regions by approximately 150 ms. Moreover, whereas pseudowords elicit larger N400s when used as verbs than when used as nouns, unambiguous nouns and ambiguous words used as nouns elicit more frontocentral negativity than unambiguous verbs and ambiguous words used as verbs, respectively. Additionally, unambiguous verbs elicit a left-lateralized, anterior positivity (approximately 200 ms) not observed for any other stimulus type, though only when these items are used appropriately as verbs (i.e. in verb-predicting contexts). In summary, the pattern of neural activity observed in response to lexical items depends on their general

  20. Ambiguity as a Motor for Communication--Differences between Hearing and Deaf Students' Ways of Reasoning about Energy

    ERIC Educational Resources Information Center

    Molander, Bengt-Olov; Hallden, Ola; Lindahl, Camilla

    2007-01-01

    Ambiguity in group discussions as a resource for communication is studied. How students, aged 13-15 years, elaborate on the concept energy through dialogue is described. Group interviews were conducted with 15 hearing and 20 deaf students. Three probes were used to initiate discussions on different meanings of energy. The results show that the…

  1. Giving Leads to Happiness in Young Children

    PubMed Central

    Aknin, Lara B.; Hamlin, J. Kiley; Dunn, Elizabeth W.

    2012-01-01

    Evolutionary models of cooperation require proximate mechanisms that sustain prosociality despite inherent costs to individuals. The “warm glow” that often follows prosocial acts could provide one such mechanism; if so, these emotional benefits may be observable very early in development. Consistent with this hypothesis, the present study finds that before the age of two, toddlers exhibit greater happiness when giving treats to others than receiving treats themselves. Further, children are happier after engaging in costly giving – forfeiting their own resources – than when giving the same treat at no cost. By documenting the emotionally rewarding properties of costly prosocial behavior among toddlers, this research provides initial support for the claim that experiencing positive emotions when giving to others is a proximate mechanism for human cooperation. PMID:22720078

  2. Know Concentration Before Giving Acetaminophen to Infants

    MedlinePlus

    ... urging consumers to carefully read the labels of liquid acetaminophen marketed for infants to avoid giving the ... less concentrated version for all children. Until now, liquid acetaminophen marketed for infants has only been available ...

  3. Integer-ambiguity resolution in astronomy and geodesy

    NASA Astrophysics Data System (ADS)

    Lannes, A.; Prieur, J.-L.

    2014-02-01

    Recent theoretical developments in astronomical aperture synthesis have revealed the existence of integer-ambiguity problems. Those problems, which appear in the self-calibration procedures of radio imaging, have been shown to be similar to the nearest-lattice point (NLP) problems encountered in high-precision geodetic positioning and in global navigation satellite systems. In this paper we analyse the theoretical aspects of the matter and propose new methods for solving those NLP~problems. The related optimization aspects concern both the preconditioning stage, and the discrete-search stage in which the integer ambiguities are finally fixed. Our algorithms, which are described in an explicit manner, can easily be implemented. They lead to substantial gains in the processing time of both stages. Their efficiency was shown via intensive numerical tests.

  4. Learning and generalization under ambiguity: an fMRI study.

    PubMed

    Chumbley, J R; Flandin, G; Bach, D R; Daunizeau, J; Fehr, E; Dolan, R J; Friston, K J

    2012-01-01

    Adaptive behavior often exploits generalizations from past experience by applying them judiciously in new situations. This requires a means of quantifying the relative importance of prior experience and current information, so they can be balanced optimally. In this study, we ask whether the brain generalizes in an optimal way. Specifically, we used Bayesian learning theory and fMRI to test whether neuronal responses reflect context-sensitive changes in ambiguity or uncertainty about experience-dependent beliefs. We found that the hippocampus expresses clear ambiguity-dependent responses that are associated with an augmented rate of learning. These findings suggest candidate neuronal systems that may be involved in aberrations of generalization, such as over-confidence.

  5. Learning and Generalization under Ambiguity: An fMRI Study

    PubMed Central

    Chumbley, J. R.; Flandin, G.; Bach, D. R.; Daunizeau, J.; Fehr, E.; Dolan, R. J.; Friston, K. J.

    2012-01-01

    Adaptive behavior often exploits generalizations from past experience by applying them judiciously in new situations. This requires a means of quantifying the relative importance of prior experience and current information, so they can be balanced optimally. In this study, we ask whether the brain generalizes in an optimal way. Specifically, we used Bayesian learning theory and fMRI to test whether neuronal responses reflect context-sensitive changes in ambiguity or uncertainty about experience-dependent beliefs. We found that the hippocampus expresses clear ambiguity-dependent responses that are associated with an augmented rate of learning. These findings suggest candidate neuronal systems that may be involved in aberrations of generalization, such as over-confidence. PMID:22275857

  6. Assignment of sex in neonates with ambiguous genitalia.

    PubMed

    Reiner, W G

    1999-08-01

    Sex assignment in the newborn with ambiguous genitalia has been based on the adequacy of the phallus in the male, potential fertility in the female, and cosmetic appearance of the reconstructed genitalia. Recent data from both the neurosciences and from clinical research, however, casts doubt on the validity of such criteria for clinical decision making. Current knowledge suggests a need to shift away from the current clinical approach and to incorporate these new data into decisions based on a broader understanding of the etiology of gender identity. Recognition of the primacy of psychosocial and psychosexual developmental outcomes for children with ambiguous genitalia is lending direction to longitudinal outcomes research. New approaches to sex assignment have been suggested, and the paradigm for sex assignment in the newborn period is in transition.

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

    SciTech Connect

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

    2014-01-10

    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.

  8. Ambiguous Loss after Lesbian Couples with Children Break up: A Case for Same-Gender Divorce

    ERIC Educational Resources Information Center

    Allen, Katherine R.

    2007-01-01

    The theory of ambiguous loss is applied to structural ambiguity and personal transcendence in the parent-child relationship following a same-gender relational ending. Working recursively through the six guidelines of ambiguous loss (finding meaning, tempering mastery, reconstructing identity, normalizing ambivalence, revising attachment, and…

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

    ERIC Educational Resources Information Center

    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.…

  10. How do owls localize interaurally phase-ambiguous signals?

    PubMed

    Saberi, K; Farahbod, H; Konishi, M

    1998-05-26

    Owls and other animals, including humans, use the difference in arrival time of sounds between the ears to determine the direction of a sound source in the horizontal plane. When an interaural time difference (ITD) is conveyed by a narrowband signal such as a tone, human beings may fail to derive the direction represented by that ITD. This is because they cannot distinguish the true ITD contained in the signal from its phase equivalents that are ITD +/- nT, where T is the period of the stimulus tone and n is an integer. This uncertainty is called phase-ambiguity. All ITD-sensitive neurons in birds and mammals respond to an ITD and its phase equivalents when the ITD is contained in narrowband signals. It is not known, however, if these animals show phase-ambiguity in the localization of narrowband signals. The present work shows that barn owls (Tyto alba) experience phase-ambiguity in the localization of tones delivered by earphones. We used sound-induced head-turning responses to measure the sound-source directions perceived by two owls. In both owls, head-turning angles varied as a sinusoidal function of ITD. One owl always pointed to the direction represented by the smaller of the two ITDs, whereas a second owl always chose the direction represented by the larger ITD (i.e., ITD - T). PMID:9600989

  11. Perceptual learning of a talker resolves lexical ambiguity

    NASA Astrophysics Data System (ADS)

    Piorkowski, Rebecca L.; Badecker, William

    2005-09-01

    Recent evidence [Allen and Miller, J. Acoust. Soc. Am. 115, 3171 (2004)] suggests that listeners are sensitive to talker-specific acoustic-phonetic properties. The present study examines whether experience with a particular talker's realization of place of articulation can eliminate the ambiguity that arises when a word like ``hen'' assimilates in place of articulation to ``hem'' in a labial context (hen best). Using a cross-modal priming paradigm, the priming effect of words that assimilate to other words was measured in two conditions. In the first condition, listeners heard examples of the talker's assimilation style in the form of words that assimilate to nonwords in a labial context (green beer) before the critical trials were heard. In the second condition, listeners did not hear any examples of the talker's assimilation style before the critical trials were heard. Evidence will be presented showing that, without previous experience with the talker's assimilation style, words that assimilate to other words create a lexical ambiguity for the listener. Additionally, evidence will be presented showing that experience with the talker's assimilation style eliminates this lexical ambiguity and allows the listener to perceive the talker's intended lexical form.

  12. B-decay CP asymmetries, discrete ambiguities, and new physics

    NASA Astrophysics Data System (ADS)

    Kayser, Boris; London, David

    2000-06-01

    The first measurements of CP violation in the B system will likely probe sin 2α, sin 2β, and cos 2γ. Assuming that the CP angles α, β, and γ are the interior angles of the unitarity triangle, these measurements determine the angle set (α,β,γ) except for a twofold discrete ambiguity. If one allows for the possibility of new physics, the presence of this discrete ambiguity can make its discovery difficult: if only one of the two candidate solutions is consistent with constraints from other measurements in the B and K systems, one is not sure whether or not new physics is present. We review the methods used to resolve the discrete ambiguity and show that, even in the presence of new physics, they can usually be used to uncover this new physics. There are some exceptions, which we describe in detail. We systematically scan the parameter space and present examples of values of (α,β,γ) and the new-physics parameters which correspond to all possibilities. Finally, we show that if one relaxes the assumption that the bag parameters BBd and BK are positive, one can no longer definitively establish the presence of new physics.

  13. The Effect of Media on Charitable Giving and Volunteering: Evidence from the "Give Five" Campaign

    ERIC Educational Resources Information Center

    Yoruk, Baris K.

    2012-01-01

    Fundraising campaigns advertised via mass media are common. To what extent such campaigns affect charitable behavior is mostly unknown, however. Using giving and volunteering surveys conducted biennially from 1988 to 1996, I investigate the effect of a national fundraising campaign, "Give Five," on charitable giving and volunteering patterns. The…

  14. The (IR-)relevance of the Gribov ambiguity in SU(2)×U(1) gauge theories with fundamental Higgs matter

    SciTech Connect

    Capri, M.A.L.; Dudal, D.; Guimaraes, M.S.; Justo, I.F.; Sorella, S.P.; and others

    2014-04-15

    It is well accepted that dealing with the Gribov ambiguity has a major impact on correlation functions in gauge-fixed Yang–Mills theories, in particular in the low momentum regime where standard perturbation theory based on the Faddeev–Popov approach fails. Recent results, derived from functional tools (Dyson–Schwinger equations or exact RG) or the effective Gribov–Zwanziger action method, pointed towards e.g. gauge boson correlation functions that are not compatible with the properties of observable degrees of freedom. Although such an observation is a welcome feature for gauge theories exhibiting confinement, it would be a discomfort for gauge theories supplemented with Higgs fields, cf. the experimental success of the electroweak model based on a SU(2)×U(1) gauge group. The purpose of this short note is to assure that the effective action resolution to the Gribov ambiguity reduces to the standard Faddeev–Popov method in the perturbative regime of sufficiently small coupling/large Higgs condensate, thereby not compromising the physical particle spectrum of massive gauge bosons and a massless photon for the SU(2)×U(1) gauge–Higgs model. The closer the theory gets to the limit of vanishing Higgs condensate, the more the Gribov problem resurfaces with all its consequences. We give some speculations w.r.t. the Fradkin–Shenker insights about the phase diagram. -- Highlights: •Gribov horizon influences gauge propagators in a strong-coupling regime. •No influence of Gribov horizon in weak-coupling. •Inclusion of U(1) factor leads to very rich behavior of propagators.

  15. A new ionosphere-free ambiguity resolution method for long-range baseline with GNSS triple-frequency signals

    NASA Astrophysics Data System (ADS)

    Xu, Ying; Ji, Shengyue; Chen, Wu; Weng, Duojie

    2015-10-01

    New GNSS systems (i.e. GPS modernization, BeiDou, and Galileo) will provide multiple navigation signals for reliable navigation services. The triple or even multiple frequency signals are expected to bring great benefits to the ambiguity resolution (AR) over long-range baselines, which is always regarded as a huge challenge. Another issue in the long baseline AR is the unmodeled ionospheric delay, which is one of the major errors in ranging signals. A new triple-frequency, ionosphere-free technique for ambiguity resolution of long-range baseline is developed in this study. In this technique, the optimal observation combinations are chosen considering the effect of ionospheric delay. At the same time, using this technique, the double difference (DD) ionospheric delay is nullified in the ambiguity search process. The performance of the new technique is examined using the simulated GPS triple frequency data as well as the real BDS observation. Results show that the ambiguity can be fixed within 10 min for GPS and BDS long-range baselines with this new technique.

  16. Reach target selection in humans using ambiguous decision cues containing variable amounts of conflicting sensory evidence supporting each target choice.

    PubMed

    Coallier, Émilie; Kalaska, John F

    2014-12-01

    Human subjects chose between two color-coded reach targets using multicolored checkerboard-like decision cues (DCs) that presented variable amounts of conflicting sensory evidence supporting both target choices. Different DCs contained different numbers of small squares of the two target colors. The most ambiguous DCs contained nearly equal numbers of squares of both target colors. The subjects reached as soon as they selected a target after the appearance of the DC ("choose-and-go" task). The choice behavior of the subjects showed many similarities to prior studies using other stimulus properties (e.g., visual motion coherence, brightness), including progressively longer response times and higher target-choice error rates for more ambiguous DCs. However, certain trends in their choice behavior could not be fully captured by simple drift-diffusion models. Allowing the subjects to view the DCs for a period of time before presenting the targets ("match-to-sample" task) resulted in much shorter response times overall, but also revealed a reluctance of subjects to commit to a decision about the predominant color of the more ambiguous DCs during the initial extended observation period. Model processing and simulation analyses suggest that the subjects might adjust the dynamics of their decision-making process on a trial-to-trial basis in response to the variable level of ambiguous and conflicting evidence in different DCs between trials.

  17. Completing the surrogate motherhood process: parental order reporters' attitudes towards surrogacy arrangements, role ambiguity and role conflict.

    PubMed

    Purewal, Satvinder; Crawshaw, Marilyn; van den Akker, Olga

    2012-06-01

    This study investigated the attitudes of parental order reporters (PORs) towards their work with surrogacy arrangements and their experiences of role conflict and role ambiguity. A questionnaire was used to assess PORs' perceptions of their role in parental order [PO] applications, attitudes towards surrogacy arrangements and the legal process and the influence of role ambiguity or conflict. Questionnaires were distributed to all PORs employed by the Children and Family Court Advisory and Support Service in England. Thirty-three PORs participated (response rate 46%) who, on average, had each completed five PO applications (range 1-40). Positive attitudes towards surrogacy and the child's needs for openness about origins were found. Concerns about the inadequacy of preparation and assessment arrangements, overseas arrangements and non-regulation of surrogacy agencies were evident. PORs with high-role ambiguity were more likely to report less positive attitudes towards the emotional consequence of surrogacy on offspring. High scores on role ambiguity and role conflict were reflected in less positive attitudes towards the parties' preparation towards parenthood. These results have implications for training, policy and practice in this area. PMID:22458916

  18. The Costs and Benefits of Deferred Giving.

    ERIC Educational Resources Information Center

    Fink, Norman S.; Metzler, Howard C.

    It is argued in this book that while there can be a significant payoff for deferred giving programs, it is important to determine their cost effectiveness. Modern business methods of cost accounting, benefits analysis, and actuarial and econometric forecasting are applied to the Pomona College plan, whose study was supported by Lilly Endowment,…

  19. Children's Causal Attributions regarding Help Giving.

    ERIC Educational Resources Information Center

    Smith, Cathleen L.; And Others

    1979-01-01

    Second- and third-grade children receiving no consequences or only social consequences for donating to needy peers attributed their behavior to a concern for the other child. Children receiving material consequences together with social consequences tended to attribute their help giving to external sources. (JMB)

  20. Community College Alumni: Predicting Who Gives

    ERIC Educational Resources Information Center

    Skari, Lisa Ann

    2014-01-01

    Due to the decrease in public funding, community colleges are in a position where they need to generate private gifts. Alumni represent the largest untapped pool of prospective donors, and the success of alumni giving at 4-year institutions illustrates the potential that exists for community colleges. To develop effective fundraising strategies,…

  1. The Role of Informative and Ambiguous Feedback in Avoidance Behavior: Empirical and Computational Findings.

    PubMed

    Moustafa, Ahmed A; Sheynin, Jony; Myers, Catherine E

    2015-01-01

    Avoidance behavior is a critical component of many psychiatric disorders, and as such, it is important to understand how avoidance behavior arises, and whether it can be modified. In this study, we used empirical and computational methods to assess the role of informational feedback and ambiguous outcome in avoidance behavior. We adapted a computer-based probabilistic classification learning task, which includes positive, negative and no-feedback outcomes; the latter outcome is ambiguous as it might signal either a successful outcome (missed punishment) or a failure (missed reward). Prior work with this task suggested that most healthy subjects viewed the no-feedback outcome as strongly positive. Interestingly, in a later version of the classification task, when healthy subjects were allowed to opt out of (i.e. avoid) responding, some subjects ("avoiders") reliably avoided trials where there was a risk of punishment, but other subjects ("non-avoiders") never made any avoidance responses at all. One possible interpretation is that the "non-avoiders" valued the no-feedback outcome so positively on punishment-based trials that they had little incentive to avoid. Another possible interpretation is that the outcome of an avoided trial is unspecified and that lack of information is aversive, decreasing subjects' tendency to avoid. To examine these ideas, we here tested healthy young adults on versions of the task where avoidance responses either did or did not generate informational feedback about the optimal response. Results showed that provision of informational feedback decreased avoidance responses and also decreased categorization performance, without significantly affecting the percentage of subjects classified as "avoiders." To better understand these results, we used a modified Q-learning model to fit individual subject data. Simulation results suggest that subjects in the feedback condition adjusted their behavior faster following better-than-expected outcomes

  2. Situational ambiguity and gendered patterns of arrest for intimate partner violence.

    PubMed

    Durfee, Alesha

    2012-01-01

    Using data from the 2005 National Incident-Based Reporting System (NIBRS), this analysis focuses on the impacts that domestic violence mandatory arrest policies have on arrest outcomes in "situationally ambiguous" cases: cases where both the female and male partners have been identified by police as both a victim and an offender. Results indicate that although officers arrest male partners more frequently than female partners, after controlling for incident and individual factors, mandatory arrest policies disproportionately affect women. Furthermore, correlates of arrest differ for male-only arrests versus female-only arrests. These findings are discussed in the context of changing legal responses to domestic violence. PMID:22411299

  3. The Role of Informative and Ambiguous Feedback in Avoidance Behavior: Empirical and Computational Findings.

    PubMed

    Moustafa, Ahmed A; Sheynin, Jony; Myers, Catherine E

    2015-01-01

    Avoidance behavior is a critical component of many psychiatric disorders, and as such, it is important to understand how avoidance behavior arises, and whether it can be modified. In this study, we used empirical and computational methods to assess the role of informational feedback and ambiguous outcome in avoidance behavior. We adapted a computer-based probabilistic classification learning task, which includes positive, negative and no-feedback outcomes; the latter outcome is ambiguous as it might signal either a successful outcome (missed punishment) or a failure (missed reward). Prior work with this task suggested that most healthy subjects viewed the no-feedback outcome as strongly positive. Interestingly, in a later version of the classification task, when healthy subjects were allowed to opt out of (i.e. avoid) responding, some subjects ("avoiders") reliably avoided trials where there was a risk of punishment, but other subjects ("non-avoiders") never made any avoidance responses at all. One possible interpretation is that the "non-avoiders" valued the no-feedback outcome so positively on punishment-based trials that they had little incentive to avoid. Another possible interpretation is that the outcome of an avoided trial is unspecified and that lack of information is aversive, decreasing subjects' tendency to avoid. To examine these ideas, we here tested healthy young adults on versions of the task where avoidance responses either did or did not generate informational feedback about the optimal response. Results showed that provision of informational feedback decreased avoidance responses and also decreased categorization performance, without significantly affecting the percentage of subjects classified as "avoiders." To better understand these results, we used a modified Q-learning model to fit individual subject data. Simulation results suggest that subjects in the feedback condition adjusted their behavior faster following better-than-expected outcomes

  4. The Role of Informative and Ambiguous Feedback in Avoidance Behavior: Empirical and Computational Findings

    PubMed Central

    Moustafa, Ahmed A.; Sheynin, Jony; Myers, Catherine E.

    2015-01-01

    Avoidance behavior is a critical component of many psychiatric disorders, and as such, it is important to understand how avoidance behavior arises, and whether it can be modified. In this study, we used empirical and computational methods to assess the role of informational feedback and ambiguous outcome in avoidance behavior. We adapted a computer-based probabilistic classification learning task, which includes positive, negative and no-feedback outcomes; the latter outcome is ambiguous as it might signal either a successful outcome (missed punishment) or a failure (missed reward). Prior work with this task suggested that most healthy subjects viewed the no-feedback outcome as strongly positive. Interestingly, in a later version of the classification task, when healthy subjects were allowed to opt out of (i.e. avoid) responding, some subjects (“avoiders”) reliably avoided trials where there was a risk of punishment, but other subjects (“non-avoiders”) never made any avoidance responses at all. One possible interpretation is that the “non-avoiders” valued the no-feedback outcome so positively on punishment-based trials that they had little incentive to avoid. Another possible interpretation is that the outcome of an avoided trial is unspecified and that lack of information is aversive, decreasing subjects’ tendency to avoid. To examine these ideas, we here tested healthy young adults on versions of the task where avoidance responses either did or did not generate informational feedback about the optimal response. Results showed that provision of informational feedback decreased avoidance responses and also decreased categorization performance, without significantly affecting the percentage of subjects classified as “avoiders.” To better understand these results, we used a modified Q-learning model to fit individual subject data. Simulation results suggest that subjects in the feedback condition adjusted their behavior faster following better

  5. Embedded promotions in online services: how goal-relevance ambiguity shapes response and affect.

    PubMed

    Brasel, S Adam

    2010-09-01

    Adding promotions to online services is increasingly commonplace, yet consumers may have difficulty determining whether service-embedded promotions are goal-relevant, due to the linear and transactional nature of online services. This contextual effect of goal-relevance ambiguity on promotions is explored across three studies. An exploratory study utilizing actual service websites and a broad range of consumers as participants showed promotional elements in online services generated considerable confusion, and instructions labeling promotions as optional did little to relieve goal-relevance ambiguity. A second study using student participants inserted promotions into an online airline ticket service, a shopping site, a local news blog, and a news headline aggregator, to explore how linear and transactional sites such as online services compared to more exploratory or informational online environments. Results showed that service-embedded promotions enjoyed initial compliance far beyond promotions in traditional websites but also generated increased confusion, frustration, and anger. A third study utilizing student participants explored how varying levels of online service experience created differing responses to promotions in services; novices were less able to judge promotional goal-relevance and experienced more confusion, whereas experienced searchers were more likely to respond with frustration and anger. Many participants complied with promotional offers at the time of the service transaction, but stated intentions to use the promotion postservice were very low. The overall results spotlight goal-relevance ambiguity as an important driver of consumer response to online promotions, and highlight the role website context can play in the processing of online promotional elements. PMID:20853986

  6. Embedded promotions in online services: how goal-relevance ambiguity shapes response and affect.

    PubMed

    Brasel, S Adam

    2010-09-01

    Adding promotions to online services is increasingly commonplace, yet consumers may have difficulty determining whether service-embedded promotions are goal-relevant, due to the linear and transactional nature of online services. This contextual effect of goal-relevance ambiguity on promotions is explored across three studies. An exploratory study utilizing actual service websites and a broad range of consumers as participants showed promotional elements in online services generated considerable confusion, and instructions labeling promotions as optional did little to relieve goal-relevance ambiguity. A second study using student participants inserted promotions into an online airline ticket service, a shopping site, a local news blog, and a news headline aggregator, to explore how linear and transactional sites such as online services compared to more exploratory or informational online environments. Results showed that service-embedded promotions enjoyed initial compliance far beyond promotions in traditional websites but also generated increased confusion, frustration, and anger. A third study utilizing student participants explored how varying levels of online service experience created differing responses to promotions in services; novices were less able to judge promotional goal-relevance and experienced more confusion, whereas experienced searchers were more likely to respond with frustration and anger. Many participants complied with promotional offers at the time of the service transaction, but stated intentions to use the promotion postservice were very low. The overall results spotlight goal-relevance ambiguity as an important driver of consumer response to online promotions, and highlight the role website context can play in the processing of online promotional elements.

  7. Ambiguity resolution in precise point positioning with hourly data for global single receiver

    NASA Astrophysics Data System (ADS)

    Zhang, Xiaohong; Li, Pan; Guo, Fei

    2013-01-01

    Integer ambiguity resolution (IAR) can improve precise point positioning (PPP) performance significantly. IAR for PPP became a highlight topic in global positioning system (GPS) community in recent years. More and more researchers focus on this issue. Progress has been made in the latest years. In this paper, we aim at investigating and demonstrating the performance of a global zero-differenced (ZD) PPP IAR service for GPS users by providing routine ZD uncalibrated fractional offsets (UFOs) for wide-lane and narrow-lane. Data sets from all IGS stations collected on DOY 1, 100, 200 and 300 of 2010 are used to validate and demonstrate this global service. Static experiment results show that an accuracy better than 1 cm in horizontal and 1-2 cm in vertical could be achieved in ambiguity-fixed PPP solution with only hourly data. Compared with PPP float solution, an average improvement reaches 58.2% in east, 28.3% in north and 23.8% in vertical for all tested stations. Results of kinematic experiments show that the RMS of kinematic PPP solutions can be improved from 21.6, 16.6 and 37.7 mm to 12.2, 13.3 and 34.3 mm for the fixed solutions in the east, north and vertical components, respectively. Both static and kinematic experiments show that wide-lane and narrow-lane UFO products of all satellites can be generated and provided in a routine way accompanying satellite orbit and clock products for the PPP user anywhere around the world, to obtain accurate and reliable ambiguity-fixed PPP solutions.

  8. Ambiguous genitalia: what prenatal genetic testing is practical?

    PubMed

    Adam, Margaret P; Fechner, Patricia Y; Ramsdell, Linda A; Badaru, Angela; Grady, Richard E; Pagon, Roberta A; McCauley, Elizabeth; Cheng, Edith Y; Parisi, Melissa A; Shnorhavorian, Margarett

    2012-06-01

    Concern for ambiguous genitalia or chromosome-phenotype discordance detected in a prenatal setting has increased over the last two decades. Practitioners faced with this prenatal finding have a variety of genetic tests available to them; however, it is unclear to what extent prenatal testing for disorders of sex development (DSD) is useful or practical. We undertook a retrospective review of the medical records of 140 individuals evaluated through the DSD clinic at Seattle Children's Hospital with birthdates from 01/01/1994 through 08/16/2011 to determine the rate of prenatal detection of ambiguous genitalia in individuals with DSD, what prenatal diagnostic workup was undertaken, and the postnatal outcome, including whether a postnatal genetic diagnosis was confirmed. Of all 140 subjects, 34 (24%) were identified prenatally. The most common postnatal diagnoses were penoscrotal hypospadias with transposition of the scrotum with no known genetic cause (24/140; 17%) and 21-hydroxylase deficiency (20/140; 14%). Apart from these, no single diagnosis comprised more than a few cases. Prenatal diagnostic testing varied widely, from no tests to multiple molecular tests with amniotic fluid hormone concentrations. In the absence of other fetal anomalies or growth retardation on ultrasound, prenatal karyotype with fluorescence in situ hybridization for the SRY gene is the most useful test when ambiguous genitalia is suspected. Further prenatal testing for Smith-Lemli-Opitz syndrome in 46,XY individuals and congenital adrenal hyperplasia in 46,XX individuals may be considered. However, targeted molecular testing for rare DSD conditions in the absence of a family history of DSD has a low yield.

  9. Dressed skeleton expansion and the coupling scale ambiguity problem

    SciTech Connect

    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 {mu}{sup 2} {approximately} Q{sub min}{sup 2}Q{sub med}{sup 2}/Q{sub max}{sup 2} where Q{sub min}{sup 2}Q{sub med}{sup 2}/Q{sub max}{sup 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.

  10. New Ambiguity in Probing CP Violation in Neutrino Oscillations.

    PubMed

    Miranda, O G; Tórtola, M; Valle, J W F

    2016-08-01

    If neutrinos get mass via the seesaw mechanism the mixing matrix describing neutrino oscillations can be effectively nonunitary. We show that in this case the neutrino appearance probabilities involve a new CP phase ϕ associated with nonunitarity. This leads to an ambiguity in extracting the "standard" three-neutrino phase δ_{CP}, which can survive even after neutrino and antineutrino channels are combined. Its existence should be taken into account in the planning of any oscillation experiment aiming at a robust measurement of δ_{CP}. PMID:27541461

  11. Sensorimotor Adaptation Following Exposure to Ambiguous Inertial Motion Cues

    NASA Technical Reports Server (NTRS)

    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.

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

    PubMed

    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.

  13. New Ambiguity in Probing C P Violation in Neutrino Oscillations

    NASA Astrophysics Data System (ADS)

    Miranda, O. G.; Tórtola, M.; Valle, J. W. F.

    2016-08-01

    If neutrinos get mass via the seesaw mechanism the mixing matrix describing neutrino oscillations can be effectively nonunitary. We show that in this case the neutrino appearance probabilities involve a new C P phase ϕ associated with nonunitarity. This leads to an ambiguity in extracting the "standard" three-neutrino phase δC P, which can survive even after neutrino and antineutrino channels are combined. Its existence should be taken into account in the planning of any oscillation experiment aiming at a robust measurement of δC P.

  14. New Ambiguity in Probing CP Violation in Neutrino Oscillations.

    PubMed

    Miranda, O G; Tórtola, M; Valle, J W F

    2016-08-01

    If neutrinos get mass via the seesaw mechanism the mixing matrix describing neutrino oscillations can be effectively nonunitary. We show that in this case the neutrino appearance probabilities involve a new CP phase ϕ associated with nonunitarity. This leads to an ambiguity in extracting the "standard" three-neutrino phase δ_{CP}, which can survive even after neutrino and antineutrino channels are combined. Its existence should be taken into account in the planning of any oscillation experiment aiming at a robust measurement of δ_{CP}.

  15. Correlations among ambiguous figures, curiosity, and spatial ability.

    PubMed

    Beer, J

    1990-12-01

    For 29 college students (6 men, 23 women) who passively viewed in each of 6 blocks both the Schroeder stair and the Necker cube for 3 min. apiece with one 3-min. rest between viewings, their frequency of reversals, sex, GPA, scores on the Wechsler Adult Intelligence Scale Information subtest, the two-dimensional Test 8, and the three-dimensional Test 9 of the Multiple Aptitude Test, measuring spatial ability, and three curiosity measures--the Which-to-Discuss Test, the Maze test, and the Ontario Test of Intrinsic Motivation--were not significantly correlated by Pearson's method with the number of ambiguous figure reversals.

  16. Tactile input and empathy modulate the perception of ambiguous biological motion

    PubMed Central

    Yiltiz, Hörmetjan; Chen, Lihan

    2015-01-01

    Evidence has shown that task-irrelevant auditory cues can bias perceptual decisions regarding directional information associated with biological motion, as indicated in perceptual tasks using point-light walkers (PLWs) (Brooks et al., 2007). In the current study, we extended the investigation of cross-modal influences to the tactile domain by asking how tactile input resolves perceptual ambiguity in visual apparent motion, and how empathy plays a role in this cross-modal interaction. In Experiment 1, we simulated the tactile feedback on the observers' fingertips when the (upright or inverted) PLWs (comprised of either all red or all green dots) were walking (leftwards or rightwards). The temporal periods between tactile events and critical visual events (the PLW's feet hitting the ground) were manipulated so that the tap could lead, synchronize, or lag the visual foot-hitting-ground event. We found that the temporal structures between tactile (feedback) and visual (hitting) events systematically biases the directional perception for upright PLWs, making either leftwards or rightwards more dominant. However, this effect was absent for inverted PLWs. In Experiment 2, we examined how empathy modulates cross-modal capture. Instead of giving tactile feedback on participants' fingertips, we gave taps on their ankles and presented the PLWs with motion directions of approaching (facing toward observer)/receding (facing away from observer) to resemble normal walking postures. With the same temporal structure, we found that individuals with higher empathy were more subject to perceptual bias in the presence of tactile feedback. Taken together, our findings showed that task-irrelevant tactile input can resolve the otherwise ambiguous perception of the direction of biological motion, and this cross-modal bias was mediated by higher level social-cognitive factors, including empathy. PMID:25750631

  17. Syntactic complexity and ambiguity resolution in a free word order language: behavioral and electrophysiological evidences from Basque.

    PubMed

    Erdocia, Kepa; Laka, Itziar; Mestres-Missé, Anna; Rodriguez-Fornells, Antoni

    2009-04-01

    In natural languages some syntactic structures are simpler than others. Syntactically complex structures require further computation that is not required by syntactically simple structures. In particular, canonical, basic word order represents the simplest sentence-structure. Natural languages have different canonical word orders, and they vary in the degree of word order freedom they allow. In the case of free word order, whether canonical word order plays any role in processing is still unclear. In this paper, we present behavioral and electrophysiological evidence that simpler, canonical word order preference is found even in a free word order language. Canonical and derived structures were compared in two self-paced reading and one ERPs experiment. Non-canonical sentences required further syntactic computation in Basque, they showed longer reading times and a modulation of anterior negativities and P600 components providing evidence that even in free word order, case-marking grammars, underlying canonical word order can play a relevant role in sentence processing. These findings could signal universal processing mechanisms because similar processing patterns are found in typologically very distant grammars. We also provide evidence from syntactically fully ambiguous sequences. Our results on ambiguity resolution showed that fully ambiguous sequences were processed as canonical sentences. Moreover, when fully ambiguous sequences were forced to complex interpretation by means of the world knowledge of the participants, a frontal negativity distinguished simple and complex ambiguous sequences. Thus the preference of simple structures is presumably a universal design property for language processing, despite differences on parametric variation of a given grammar. PMID:19223065

  18. GNSS Carrier Phase Integer Ambiguity Resolution with Camera and Satellite images

    NASA Astrophysics Data System (ADS)

    Henkel, Patrick

    2015-04-01

    Ambiguity Resolution is the key to high precision position and attitude determination with GNSS. However, ambiguity resolution of kinematic receivers becomes challenging in environments with substantial multipath, limited satellite availability and erroneous cycle slip corrections. There is a need for other sensors, e.g. inertial sensors that allow an independent prediction of the position. The change of the predicted position over time can then be used for cycle slip detection and correction. In this paper, we provide a method to improve the initial ambiguity resolution for RTK and PPP with vision-based position information. Camera images are correlated with geo-referenced aerial/ satellite images to obtain an independent absolute position information. This absolute position information is then coupled with the GNSS and INS measurements in an extended Kalman filter to estimate the position, velocity, acceleration, attitude, angular rates, code multipath and biases of the accelerometers and gyroscopes. The camera and satellite images are matched based on some characteristic image points (e.g. corners of street markers). We extract these characteristic image points from the camera images by performing the following steps: An inverse mapping (homogenous projection) is applied to transform the camera images from the driver's perspective to bird view. Subsequently, we detect the street markers by performing (a) a color transformation and reduction with adaptive brightness correction to focus on relevant features, (b) a subsequent morphological operation to enhance the structure recognition, (c) an edge and corner detection to extract feature points, and (d) a point matching of the corner points with a template to recognize the street markers. We verified the proposed method with two low-cost u-blox LEA 6T GPS receivers, the MPU9150 from Invensense, the ASCOS RTK corrections and a PointGrey camera. The results show very precise and seamless position and attitude

  19. 'I give staff time to care'.

    PubMed

    Lomas, Clare

    Flo Panel-Coates is working to improve care at a heavily criticised NHS trust. Since taking on the director of nursing post in October 2012, she has secured more support for ward leaders, giving them time to do their job, improved the skill mix of staff, and cut senior nurses' paperwork. Ensuring staff work consistently to the highest standard is the NHS's biggest challenge, she says.

  20. Satiation or availability? Effects of attention, memory, and imagery on the perception of ambiguous figures

    NASA Technical Reports Server (NTRS)

    Horlitz, Krista L.; O'Leary, Ann

    1993-01-01

    The prolonged-inspection technique has been used to demonstrate effects of satiation on the perception of ambiguous figures. We propose that the inspection phase, in which subjects view an unambiguous version of the stimulus prior to observing the ambiguous figure, does not create neural fatigue but rather provides a context in which the alternative percept is apprehended and gains perceptual strength through processes such as imagination or memory. The consequent availability of the alternative organization drives the perceptual phenomena that have been thought to reflect satiation. In Experiment 1, we demonstrated that (1) preexperimental exposure to the target figures and (2) allocation of attention to the inspection figures were both necessary in order to obtain results similar to those predicted by the satiation model. In Experiment 2, we obtained similar results, finding that effects of prior inspection were greater the greater the amount and availability of information regarding the alternative percept during the inspection phase. Subjects who generated visual images of the noninspected alternative during inspection yielded results comparable to those from subjects to whom both versions were presented visually.

  1. Statistical analysis of the ambiguities in the asteroid period determinations

    NASA Astrophysics Data System (ADS)

    Butkiewicz, M.; Kwiatkowski, T.; Bartczak, P.; Dudziński, G.

    2014-07-01

    A synodic period of an asteroid can be derived from its lightcurve by standard methods like Fourier-series fitting. A problem appears when results of observations are based on less than a full coverage of a lightcurve and/or high level of noise. Also, long gaps between individual lightcurves create an ambiguity in the cycle count which leads to aliases. Excluding binary systems and objects with non-principal-axis rotation, the rotation period is usually identical to the period of the second Fourier harmonic of the lightcurve. There are cases, however, where it may be connected with the 1st, 3rd, or 4th harmonic and it is difficult to choose among them when searching for the period. To help remove such uncertainties we analysed asteroid lightcurves for a range of shapes and observing/illuminating geometries. We simulated them using a modified internal code from the ISAM service (Marciniak et al. 2012, A&A 545, A131). In our computations, shapes of asteroids were modeled as Gaussian random spheres (Muinonen 1998, A&A, 332, 1087). A combination of Lommel-Seeliger and Lambert scattering laws was assumed. For each of the 100 shapes, we randomly selected 1000 positions of the spin axis, systematically changing the solar phase angle with a step of 5°. For each lightcurve, we determined its peak-to-peak amplitude, fitted the 6th-order Fourier series and derived the amplitudes of its harmonics. Instead of the number of the lightcurve extrema, which in many cases is subjective, we characterized each lightcurve by the order of the highest-amplitude Fourier harmonic. The goal of our simulations was to derive statistically significant conclusions (based on the underlying assumptions) about the dominance of different harmonics in the lightcurves of the specified amplitude and phase angle. The results, presented in the Figure, can be used in individual cases to estimate the probability that the obtained lightcurve is dominated by a specified Fourier harmonic. Some of the

  2. Stochastic exploration of ambiguities for nonrigid shape recovery.

    PubMed

    Moreno-Noguer, Francesc; Fua, Pascal

    2013-02-01

    Recovering the 3D shape of deformable surfaces from single images is known to be a highly ambiguous problem because many different shapes may have very similar projections. This is commonly addressed by restricting the set of possible shapes to linear combinations of deformation modes and by imposing additional geometric constraints. Unfortunately, because image measurements are noisy, such constraints do not always guarantee that the correct shape will be recovered. To overcome this limitation, we introduce a stochastic sampling approach to efficiently explore the set of solutions of an objective function based on point correspondences. This allows us to propose a small set of ambiguous candidate 3D shapes and then use additional image information to choose the best one. As a proof of concept, we use either motion or shading cues to this end and show that we can handle a complex objective function without having to solve a difficult nonlinear minimization problem. The advantages of our method are demonstrated on a variety of problems including both real and synthetic data.

  3. Radiological Evaluation of Ambiguous Genitalia with Various Imaging Modalities

    NASA Astrophysics Data System (ADS)

    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.

  4. Vaccine Hesitancy: Clarifying a Theoretical Framework for an Ambiguous Notion

    PubMed Central

    Peretti-Watel, Patrick; Larson, Heidi J; Ward, Jeremy K.; Schulz, William S; Verger, Pierre

    2015-01-01

    Today, according to many public health experts, public confidence in vaccines is waning. The term “vaccine hesitancy” (VH) is increasingly used to describe the spread of such vaccine reluctance. But VH is an ambiguous notion and its theoretical background appears uncertain. To clarify this concept, we first review the current definitions of VH in the public health literature and examine its most prominent characteristics. VH has been defined as a set of beliefs, attitudes, or behaviours, or some combination of them, shared by a large and heterogeneous portion of the population and including people who exhibit reluctant conformism (they may either decline a vaccine, delay it or accept it despite their doubts) and vaccine-specific behaviours. Secondly, we underline some of the ambiguities of this notion and argue that it is more a catchall category than a real concept. We also call into question the usefulness of understanding VH as an intermediate position along a continuum ranging from anti-vaccine to pro-vaccine attitudes, and we discuss its qualification as a belief, attitude or behaviour. Thirdly, we propose a theoretical framework, based on previous literature and taking into account some major structural features of contemporary societies, that considers VH as a kind of decision-making process that depends on people’s level of commitment to healthism/risk culture and on their level of confidence in the health authorities and mainstream medicine. PMID:25789201

  5. Speech Rhythm Facilitates Syntactic Ambiguity Resolution: ERP Evidence

    PubMed Central

    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. PMID:23409109

  6. Psychoanalytic and musical ambiguity: the tritone in gee, officer krupke.

    PubMed

    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. PMID:20234007

  7. Stochastic exploration of ambiguities for nonrigid shape recovery.

    PubMed

    Moreno-Noguer, Francesc; Fua, Pascal

    2013-02-01

    Recovering the 3D shape of deformable surfaces from single images is known to be a highly ambiguous problem because many different shapes may have very similar projections. This is commonly addressed by restricting the set of possible shapes to linear combinations of deformation modes and by imposing additional geometric constraints. Unfortunately, because image measurements are noisy, such constraints do not always guarantee that the correct shape will be recovered. To overcome this limitation, we introduce a stochastic sampling approach to efficiently explore the set of solutions of an objective function based on point correspondences. This allows us to propose a small set of ambiguous candidate 3D shapes and then use additional image information to choose the best one. As a proof of concept, we use either motion or shading cues to this end and show that we can handle a complex objective function without having to solve a difficult nonlinear minimization problem. The advantages of our method are demonstrated on a variety of problems including both real and synthetic data. PMID:22547426

  8. Psychoanalytic and musical ambiguity: the tritone in gee, officer krupke.

    PubMed

    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. Narrowing historical uncertainty: probabilistic classification of ambiguously identified tree species in historical forest survey data

    USGS Publications Warehouse

    Mladenoff, D.J.; Dahir, S.E.; Nordheim, E.V.; Schulte, L.A.; Guntenspergen, G.R.

    2002-01-01

    Historical data have increasingly become appreciated for insight into the past conditions of ecosystems. Uses of such data include assessing the extent of ecosystem change; deriving ecological baselines for management, restoration, and modeling; and assessing the importance of past conditions on the composition and function of current systems. One historical data set of this type is the Public Land Survey (PLS) of the United States General Land Office, which contains data on multiple tree species, sizes, and distances recorded at each survey point, located at half-mile (0.8 km) intervals on a 1-mi (1.6 km) grid. This survey method was begun in the 1790s on US federal lands extending westward from Ohio. Thus, the data have the potential of providing a view of much of the US landscape from the mid-1800s, and they have been used extensively for this purpose. However, historical data sources, such as those describing the species composition of forests, can often be limited in the detail recorded and the reliability of the data, since the information was often not originally recorded for ecological purposes. Forest trees are sometimes recorded ambiguously, using generic or obscure common names. For the PLS data of northern Wisconsin, USA, we developed a method to classify ambiguously identified tree species using logistic regression analysis, using data on trees that were clearly identified to species and a set of independent predictor variables to build the models. The models were first created on partial data sets for each species and then tested for fit against the remaining data. Validations were conducted using repeated, random subsets of the data. Model prediction accuracy ranged from 81% to 96% in differentiating congeneric species among oak, pine, ash, maple, birch, and elm. Major predictor variables were tree size, associated species, landscape classes indicative of soil type, and spatial location within the study region. Results help to clarify ambiguities

  10. The kindergarten path effect revisited: children's use of context in processing structural ambiguities.

    PubMed

    Weighall, Anna R

    2008-02-01

    Research with adults has shown that ambiguous spoken sentences are resolved efficiently, exploiting multiple cues--including referential context--to select the intended meaning. Paradoxically, children appear to be insensitive to referential cues when resolving ambiguous sentences, relying instead on statistical properties intrinsic to the language such as verb biases. The possibility that children's insensitivity to referential context may be an artifact of the experimental design used in previous work was explored with 60 4- to 11-year-olds. An act-out task was designed to discourage children from making incorrect pragmatic inferences and to prevent premature and ballistic responses by enforcing delayed actions. Performance on this task was compared directly with the standard act-out task used in previous studies. The results suggest that young children (5 years) do not use contextual information, even under conditions designed to maximize their use of such cues, but that adult-like processing is evident by approximately 8 years of age. These results support and extend previous findings by Trueswell and colleagues (Cognition (1999), Vol. 73, pp. 89-134) and are consistent with a constraint-based learning account of children's linguistic development.

  11. Interpreting Quantifier Scope Ambiguity: Evidence of Heuristic First, Algorithmic Second Processing

    PubMed Central

    Dwivedi, Veena D.

    2013-01-01

    The present work suggests that sentence processing requires both heuristic and algorithmic processing streams, where the heuristic processing strategy precedes the algorithmic phase. This conclusion is based on three self-paced reading experiments in which the processing of two-sentence discourses was investigated, where context sentences exhibited quantifier scope ambiguity. Experiment 1 demonstrates that such sentences are processed in a shallow manner. Experiment 2 uses the same stimuli as Experiment 1 but adds questions to ensure deeper processing. Results indicate that reading times are consistent with a lexical-pragmatic interpretation of number associated with context sentences, but responses to questions are consistent with the algorithmic computation of quantifier scope. Experiment 3 shows the same pattern of results as Experiment 2, despite using stimuli with different lexical-pragmatic biases. These effects suggest that language processing can be superficial, and that deeper processing, which is sensitive to structure, only occurs if required. Implications for recent studies of quantifier scope ambiguity are discussed. PMID:24278439

  12. Advice on Giving a Scientific Talk

    NASA Astrophysics Data System (ADS)

    Kurtz, D. W.

    2006-04-01

    What makes one speaker exciting and another boring? You have been to good talks and you have sat through far too many poor ones, so what makes the difference? It doesn't really matter whether it is a scientific talk, a public talk or a classroom lecture: Your prime concern is to think about the audience. You are talking to them. You are performing. Look at them; talk to them; think about what they are hearing and seeing. They very much want you to give a good talk -- that is why they have chosen to be your audience. But at the start of your talk they are worried you might not, so they are nervous. Your first job is to relax them and get their trust that you are going to do a good job. Then you will relax and you will be off to a great start. Of course your content matters; if you have a great discovery, they will forgive you anything. But it is still better to make a good presentation. I give some advice here on what to do, and what not to do, when giving any kind of talk, but with emphasis on short scientific talks presented at conferences. You should be a little nervous at the start of a talk - that is caused by your concern to do a good job. With a good start your talk will flow, you will then present your discoveries, and with a good ending your audience will applaud appreciatively and want to ask you questions. You will have enjoyed performing and want to do it again. Speaking can be fun for you, and rewarding for your audiences.

  13. Nurses' intentions to give lifestyle support.

    PubMed

    McKenzie, Karen

    Models of behaviour change can help identify factors that influence health behaviours such as eating a healthy diet and physical activity. The Theory of Planned Behaviour has been shown to be relatively effective at predicting people's intention to engage in health-related behaviours. More recent research has explored whether it can help predict the intentions of one group of people to support another group to engage in healthy behaviour. This has implications for nurses, who are often facilitators of patient health. This article gives an overview of the model and discusses its potential implications for nurses.

  14. Nurses' intentions to give lifestyle support.

    PubMed

    McKenzie, Karen

    Models of behaviour change can help identify factors that influence health behaviours such as eating a healthy diet and physical activity. The Theory of Planned Behaviour has been shown to be relatively effective at predicting people's intention to engage in health-related behaviours. More recent research has explored whether it can help predict the intentions of one group of people to support another group to engage in healthy behaviour. This has implications for nurses, who are often facilitators of patient health. This article gives an overview of the model and discusses its potential implications for nurses. PMID:25087266

  15. Resolving ambiguities in nanowire field-effect transistor characterization.

    PubMed

    Heedt, Sebastian; Otto, Isabel; Sladek, Kamil; Hardtdegen, Hilde; Schubert, Jürgen; Demarina, Natalia; Lüth, Hans; Grützmacher, Detlev; Schäpers, Thomas

    2015-11-21

    We have modeled InAs nanowires using finite element methods considering the actual device geometry, the semiconducting nature of the channel and surface states, providing a comprehensive picture of charge distribution and gate action. The effective electrostatic gate width and screening effects are taken into account. A pivotal aspect is that the gate coupling to the nanowire is compromised by the concurrent coupling of the gate electrode to the surface/interface states, which provide the vast majority of carriers for undoped nanowires. In conjunction with field-effect transistor (FET) measurements using two gates with distinctly dissimilar couplings, the study reveals the density of surface states that gives rise to a shallow quantum well at the surface. Both gates yield identical results for the electron concentration and mobility only at the actual surface state density. Our method remedies the flaws of conventional FET analysis and provides a straightforward alternative to intricate Hall effect measurements on nanowires. PMID:26482127

  16. Interpretive bias of ambiguous facial expressions in older adults with depressive symptoms.

    PubMed

    Dai, Bibing; Li, Juan; Chen, Tingji; Li, Qi

    2015-03-01

    Cognitive theories of emotional disorders indicate that biases in cognitive processes, such as attention, memory, and interpretation, are common factors that indicate vulnerability to these disorders, although their form varies according to the type of disorder. However, most of the studies have focused on adolescence and adulthood. It is still uncertain whether cognitive biases are risk factors for late-life depression. The present study sought to explore the role of interpretive bias in older adults with depressive symptoms and whether this effect is independent of basic cognitive abilities. Therefore, 18 older adults with depressive symptoms and 21 healthy controls were compared with an ambiguous facial expression identification task, a Mini Mental Status Examination, a Trail Making Test A and B, and a Word Fluency Test. Findings revealed that the depressive group was more likely to identify more ambiguous happy-sad facial expressions as indicative of sadness than were the healthy controls, but the two groups showed no significant differences in the cognitive test scores. These results suggest that interpretive bias indicates vulnerability to late-life depression, but basic cognitive abilities may have no influence in this context. PMID:26263528

  17. Resolution of sensory ambiguities for gaze stabilization requires a second neural integrator

    NASA Technical Reports Server (NTRS)

    Green, Andrea M.; Angelaki, Dora E.

    2003-01-01

    The ability to simultaneously move in the world and maintain stable visual perception depends critically on the contribution of vestibulo-ocular reflexes (VORs) to gaze stabilization. It is traditionally believed that semicircular canal signals drive compensatory responses to rotational head disturbances (rotational VOR), whereas otolith signals compensate for translational movements [translational VOR (TVOR)]. However, a sensory ambiguity exists because otolith afferents are activated similarly during head translations and reorientations relative to gravity (i.e., tilts). Extra-otolith cues are, therefore, necessary to ensure that dynamic head tilts do not elicit a TVOR. To investigate how extra-otolith signals contribute, we characterized the temporal and viewing distance-dependent properties of a TVOR elicited in the absence of a lateral acceleration stimulus to the otoliths during combined translational/rotational motion. We show that, in addition to otolith signals, angular head position signals derived by integrating sensory canal information drive the TVOR. A physiological basis for these results is proposed in a model with two distinct integration steps. Upstream of the well known oculomotor velocity-to-position neural integrator, the model incorporates a separate integration element that could represent the "velocity storage integrator," whose functional role in the oculomotor system has so far remained controversial. We propose that a key functional purpose of the velocity storage network is to temporally integrate semicircular canal signals, so that they may be used to extract translation information from ambiguous otolith afferent signals in the natural and functionally relevant bandwidth of head movements.

  18. Effects of Acute Stress on Decision Making under Ambiguous and Risky Conditions in Healthy Young Men.

    PubMed

    Cano-López, Irene; Cano-López, Beatriz; Hidalgo, Vanesa; González-Bono, Esperanza

    2016-01-01

    Acute stress and decision making (DM) interact in life - although little is known about the role of ambiguity and risk in this interaction. The aim of this study is to clarify the effect of acute stress on DM under various conditions. Thirty-one young healthy men were randomly distributed into two groups: experimental and control. DM processes were evaluated before and after an experimental session. For the experimental group, the session consisted of an acute stress battery; and the protocol was similar for the control group but the instructions were designed to minimize acute stress. Cardiovascular variables were continuously recorded 30 minutes before the DM tasks and during the experimental session. Cortisol, glucose, mood responses, and personality factors were also assessed. Acute stress was found to enhance disadvantageous decisions under ambiguous conditions (F(1, 29) = 4.16, p = .05, η2 p = .13), and this was mainly explained by the stress induced cortisol response (26.1% of variance, F(1, 30) = 11.59, p = .002). While there were no significant effects under risky conditions, inhibition responses differed between groups (F(1, 29) = 4.21, p = .05, η2 p = .13) and these differences were explained by cardiovascular and psychological responses (39.1% of variance, F(3, 30) = 7.42, p < .001). Results suggest that DM tasks could compete with cognitive resources after acute stress and could have implications for intervention in acute stress effects on DM in contexts such as addiction or eating disorders. PMID:27644414

  19. Trait Anxiety Has Effect on Decision Making under Ambiguity but Not Decision Making under Risk

    PubMed Central

    Zhang, Long; Wang, Kai; Zhu, Chunyan; Yu, Fengqiong; Chen, Xingui

    2015-01-01

    Previous studies have reported that trait anxiety (TA) affects decision making. However, results remain largely inconsistent across studies. The aim of the current study was to further address the interaction between TA and decision making. 304 subjects without depression from a sample consisting of 642 participants were grouped into high TA (HTA), medium TA (MTA) and low TA (LTA) groups based on their TA scores from State Trait Anxiety Inventory. All subjects were assessed with the Iowa Gambling Task (IGT) that measures decision making under ambiguity and the Game of Dice Task (GDT) that measures decision making under risk. While the HTA and LTA groups performed worse on the IGT compared to the MTA group, performances on the GDT between the three groups did not differ. Furthermore, the LTA and HTA groups showed different individual deck level preferences in the IGT: the former showed a preference for deck B indicating that these subjects focused more on the magnitude of rewards, and the latter showed a preference for deck A indicating significant decision making impairment. Our findings suggest that trait anxiety has effect on decision making under ambiguity but not decision making under risk and different levels of trait anxiety related differently to individual deck level preferences in the IGT. PMID:26000629

  20. Interpretation of ambiguity: Differences between children and adolescents with and without an anxiety disorder

    PubMed Central

    Waite, Polly; Codd, Jon; Creswell, Cathy

    2015-01-01

    Background Theory and treatment of anxiety disorders in young people are commonly based on the premise that interpretation biases found in anxious adults are also found in children and adolescents. Although there is some evidence that this may be the case, studies have not typically taken age into account, which is surprising given the normative changes in cognition that occur throughout childhood. The aim of the current study was to identify whether associations between anxiety disorder status and interpretation biases differed in children and adolescents. Methods The responses of children (7–10 years) and adolescents (13–16 years) with and without anxiety disorders (n=120) were compared on an ambiguous scenarios task. Results Children and adolescents with an anxiety disorder showed significantly higher levels of threat interpretation and avoidant strategies than non-anxious children and adolescents. However, age significantly moderated the effect of anxiety disorder status on interpretation of ambiguity, in that adolescents with anxiety disorders showed significantly higher levels of threat interpretation and associated negative emotion than non-anxious adolescents, but a similar relationship was not observed among children. Conclusions The findings suggest that theoretical accounts of interpretation biases in anxiety disorders in children and adolescents should distinguish between different developmental periods. For both ages, treatment that targets behavioral avoidance appears warranted. However, while adolescents are likely to benefit from treatment that addresses interpretation biases, there may be limited benefit for children under the age of ten. PMID:26363617

  1. Living With Ambiguity: A Metasynthesis of Qualitative Research on Mild Cognitive Impairment

    PubMed Central

    Gomersall, Tim; Astell, Arlene; Nygård, Louise; Sixsmith, Andrew; Mihailidis, Alex; Hwang, Amy

    2015-01-01

    Purpose of the study: Mild Cognitive Impairment (MCI) is a diagnosis proposed to describe an intermediate state between normal cognitive aging and dementia. MCI has been criticised for its conceptual fuzziness, its ambiguous relationship to dementia, and the tension it creates between medical and sociological understandings of “normal aging”. Design and Methods: We examined the published qualitative literature on experiences of being diagnosed and living with MCI using metasynthesis as the methodological framework. Results: Two overarching conceptual themes were developed. The first, MCI and myself-in-time, showed that a diagnosis of MCI could profoundly affect a person’s understanding of their place in the world. This impact appears to be mediated by multiple factors including a person’s social support networks, which daily activities are affected, and subjective interpretations of the meaning of MCI. The second theme, Living with Ambiguity, describes the difficulties people experienced in making sense of their diagnosis. Uncertainty arose, in part, from lack of clarity and consistency in the information received by people with MCI, including whether they are even told MCI is the diagnosis. Implications: We conclude by suggesting an ethical tension is always at play when a MCI diagnosis is made. Specifically, earlier support and services afforded by a diagnosis may come at the expense of a person’s anxiety about the future, with continued uncertainty about how his or her concerns and needs can be addressed. PMID:26315317

  2. Freud in Trieste: journey to an ambiguous city.

    PubMed

    Gandolfi, Laura

    2010-01-01

    This article provides an insightful exploration of the relationship between Sigmund Freud and the city of Trieste. Through an analysis of the correspondence between Freud and his friend Eduard Silberstein, Gandolfi follows those places visited by the future father of psychoanalysis and analyses their link to Freud's life. The journey to Trieste is considered as an experience that played a fundamental role in his future decisions as well as in the development of some of his psychoanalytic theories. The article eventually relates the ambiguous nature of the city - a peculiar space in with North and South, East and West converge - to Freud's own Triestine experience, that not only remits to his initial scientific researches, but also symbolizes a first significant contact with the world of sexuality. PMID:20842812

  3. Freud in Trieste: journey to an ambiguous city.

    PubMed

    Gandolfi, Laura

    2010-01-01

    This article provides an insightful exploration of the relationship between Sigmund Freud and the city of Trieste. Through an analysis of the correspondence between Freud and his friend Eduard Silberstein, Gandolfi follows those places visited by the future father of psychoanalysis and analyses their link to Freud's life. The journey to Trieste is considered as an experience that played a fundamental role in his future decisions as well as in the development of some of his psychoanalytic theories. The article eventually relates the ambiguous nature of the city - a peculiar space in with North and South, East and West converge - to Freud's own Triestine experience, that not only remits to his initial scientific researches, but also symbolizes a first significant contact with the world of sexuality.

  4. Sensorimotor Adaptations Following Exposure to Ambiguous Inertial Motion Cues

    NASA Technical Reports Server (NTRS)

    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.

  5. Success, failure and ambiguity of the dilution effect among competitors.

    PubMed

    Strauss, Alexander T; Civitello, David J; Cáceres, Carla E; Hall, Spencer R

    2015-09-01

    It remains challenging to predict variation in the magnitude of disease outbreaks. The dilution effect seeks to explain this variation by linking multiple host species to disease transmission. It predicts that disease risk increases for a focal host when host species diversity declines. However, when an increase in species diversity does not reduce disease, we are often unable to diagnose why. Here, we increase mechanistic and predictive clarity of the dilution effect with a general trait-based model of disease transmission in multi-host communities. Then, we parameterise and empirically test our model with a multi-generational case study of planktonic disease. The model-experiment combination shows that hosts that vary in competitive ability (R*) and potential to spread disease (R0 ) can produce three qualitatively disparate outcomes of dilution on disease: the dilution effect can succeed, fail, or be ambiguous/irrelevant.

  6. Ambiguity and nonidentifiability in the statistical analysis of neural codes

    PubMed Central

    Amarasingham, Asohan; Geman, Stuart; Harrison, Matthew T.

    2015-01-01

    Many experimental studies of neural coding rely on a statistical interpretation of the theoretical notion of the rate at which a neuron fires spikes. For example, neuroscientists often ask, “Does a population of neurons exhibit more synchronous spiking than one would expect from the covariability of their instantaneous firing rates?” For another example, “How much of a neuron’s observed spiking variability is caused by the variability of its instantaneous firing rate, and how much is caused by spike timing variability?” However, a neuron’s theoretical firing rate is not necessarily well-defined. Consequently, neuroscientific questions involving the theoretical firing rate do not have a meaning in isolation but can only be interpreted in light of additional statistical modeling choices. Ignoring this ambiguity can lead to inconsistent reasoning or wayward conclusions. We illustrate these issues with examples drawn from the neural-coding literature. PMID:25934918

  7. The Fungus Candida albicans Tolerates Ambiguity at Multiple Codons

    PubMed Central

    Simões, João; Bezerra, Ana R.; Moura, Gabriela R.; Araújo, Hugo; Gut, Ivo; Bayes, Mónica; Santos, Manuel A. S.

    2016-01-01

    The ascomycete Candida albicans is a normal resident of the gastrointestinal tract of humans and other warm-blooded animals. It occurs in a broad range of body sites and has high capacity to survive and proliferate in adverse environments with drastic changes in oxygen, carbon dioxide, pH, osmolarity, nutrients, and temperature. Its biology is unique due to flexible reassignment of the leucine CUG codon to serine and synthesis of statistical proteins. Under standard growth conditions, CUG sites incorporate leucine (3% of the times) and serine (97% of the times) on a proteome wide scale, but leucine incorporation fluctuates in response to environmental stressors and can be artificially increased up to 98%. In order to determine whether such flexibility also exists at other codons, we have constructed several serine tRNAs that decode various non-cognate codons. Expression of these tRNAs had minor effects on fitness, but growth of the mistranslating strains at different temperatures, in medium with different pH and nutrients composition was often enhanced relatively to the wild type (WT) strain, supporting our previous data on adaptive roles of CUG ambiguity in variable growth conditions. Parallel evolution of the recombinant strains (100 generations) followed by full genome resequencing identified various strain specific single nucleotide polymorphisms (SNP) and one SNP in the deneddylase (JAB1) gene in all strains. Since JAB1 is a subunit of the COP9 signalosome complex, which interacts with cullin (Cdc53p) to mediate degradation of a variety of cellular proteins, our data suggest that neddylation plays a key role in tolerance and adaptation to codon ambiguity in C. albicans. PMID:27065968

  8. Improved ambiguity resolution for URTK with dynamic atmosphere constraints

    NASA Astrophysics Data System (ADS)

    Tang, Weiming; Liu, Wenjian; Zou, Xuan; Li, Zongnan; Chen, Liang; Deng, Chenlong; Shi, Chuang

    2016-06-01

    Raw observation processing method with prior knowledge of ionospheric delay could strengthen the ambiguity resolution (AR), but it does not make full use of the relatively longer wavelength of wide-lane (WL) observation. Furthermore, the accuracy of calculated atmospheric delays from the regional augmentation information has quite different in quality, while the atmospheric constraint used in the current methods is usually set to an empirical value. A proper constraint, which matches the accuracy of calculated atmospheric delays, can most effectively compensate the residual systematic biases caused by large inter-station distances. Therefore, the standard deviation of the residual atmospheric parameters should be fine-tuned. This paper presents an atmosphere-constrained AR method for undifferenced network RTK (URTK) rover, whose ambiguities are sequentially fixed according to their wavelengths. Furthermore, this research systematically analyzes the residual atmospheric error and finds that it mainly varies along the positional relationship between the rover and the chosen reference stations. More importantly, its ionospheric part of certain location will also be cyclically influenced every day. Therefore, the standard deviation of residual ionospheric error can be modeled by a daily repeated cosine or other functions with the help of data one day before, and applied by rovers as pseudo-observation. With the data collected at 29 stations from a continuously operating reference station network in Guangdong Province (GDCORS) in China, the efficiency of the proposed approach is confirmed by improving the success and error rates of AR for 10-20 % compared to that of the WL-L1-IF one, as well as making much better positioning accuracy.

  9. Giving birth. Voices of Chinese women.

    PubMed

    Kartchner, Robin; Callister, Lynn

    2003-06-01

    The meaning of the childbirth experience for Chinese women living in the People's Republic of China is described in this phenomenological study. Ten primiparous women participated in audiotaped interviews within 5 months of giving birth, 9 from Beijing and 1 from Chongqing. The interviews were translated by a bilingual native Chinese speaker and transcribed by the researcher. Themes were identified from the rich narrative data, including the One Child Policy's influence on childbearing, the transition to motherhood, and the influence of the cultural practice of "doing the month" (zuo yue zi). The findings provide insights into how nurses can provide better nursing care by learning about and validating specific cultural practices related to childbearing. The rising number of Chinese immigrants to the United States reflects the increasing need for more culturally competent care by nurses to ensure positive perinatal health outcomes.

  10. Rapid Linguistic Ambiguity Resolution in Young Children with Autism Spectrum Disorder: Eye Tracking Evidence for the Limits of Weak Central Coherence.

    PubMed

    Hahn, Noemi; Snedeker, Jesse; Rabagliati, Hugh

    2015-12-01

    Individuals with autism spectrum disorders (ASD) have often been reported to have difficulty integrating information into its broader context, which has motivated the Weak Central Coherence theory of ASD. In the linguistic domain, evidence for this difficulty comes from reports of impaired use of linguistic context to resolve ambiguous words. However, recent work has suggested that impaired use of linguistic context may not be characteristic of ASD, and is instead better explained by co-occurring language impairments. Here, we provide a strong test of these claims, using the visual world eye tracking paradigm to examine the online mechanisms by which children with autism resolve linguistic ambiguity. To address concerns about both language impairments and compensatory strategies, we used a sample whose verbal skills were strong and whose average age (7; 6) was lower than previous work on lexical ambiguity resolution in ASD. Participants (40 with autism and 40 controls) heard sentences with ambiguous words in contexts that either strongly supported one reading or were consistent with both (John fed/saw the bat). We measured activation of the unintended meaning through implicit semantic priming of an associate (looks to a depicted baseball glove). Contrary to the predictions of weak central coherence, children with ASD, like controls, quickly used context to resolve ambiguity, selecting appropriate meanings within a second. We discuss how these results constrain the generality of weak central coherence.

  11. Happy hamsters? Enrichment induces positive judgement bias for mildly (but not truly) ambiguous cues to reward and punishment in Mesocricetus auratus

    PubMed Central

    Bethell, Emily J.; Koyama, Nicola F.

    2015-01-01

    Recent developments in the study of animal cognition and emotion have resulted in the ‘judgement bias’ model of animal welfare. Judgement biases describe the way in which changes in affective state are characterized by changes in information processing. In humans, anxiety and depression are characterized by increased expectation of negative events and negative interpretation of ambiguous information. Positive wellbeing is associated with enhanced expectation of positive outcomes and more positive interpretation of ambiguous information. Mood-congruent judgement biases for ambiguous information have been demonstrated in a range of animal species, with large variation in the way tests are administered and in the robustness of analyses. We highlight and address some issues using a laboratory species not previously tested: the Syrian hamster (Mesocricetus auratus). Hamsters were tested using a spatial judgement go/no-go task in enriched and unenriched housing. We included a number of controls and additional behavioural tests and applied a robust analytical approach using linear mixed effects models. Hamsters approached the ambiguous cues significantly more often when enriched than unenriched. There was no effect of enrichment on responses to the middle cue. We discuss these findings in light of mechanisms underlying processing cues to reward, punishment and true ambiguity, and the implications for the welfare of laboratory hamsters. PMID:26587255

  12. She looks sad, but he looks mad: the effects of age, gender, and ambiguity on emotion perception.

    PubMed

    Parmley, Maria; Cunningham, Joseph G

    2014-01-01

    This study investigated how target sex, target age, and expressive ambiguity influence emotion perception. Undergraduate participants (N = 192) watched morphed video clips of eight child and eight adult facial expressions shifting from neutral to either sadness or anger. Participants were asked to stop the video clip when they first saw an emotion appear (perceptual sensitivity) and were asked to identify the emotion that they saw (accuracy). Results indicate that female participants identified sad expressions sooner in female targets than in male targets. Participants were also more accurate identifying angry facial expressions by male children than by female children. Findings are discussed in terms of the effects of ambiguity, gender, and age on the perception of emotional expressions.

  13. Revisiting Neil Armstrongs Moon-Landing Quote: Implications for Speech Perception, Function Word Reduction, and Acoustic Ambiguity.

    PubMed

    Baese-Berk, Melissa M; Dilley, Laura C; Schmidt, Stephanie; Morrill, Tuuli H; Pitt, Mark A

    2016-01-01

    Neil Armstrong insisted that his quote upon landing on the moon was misheard, and that he had said one small step for a man, instead of one small step for man. What he said is unclear in part because function words like a can be reduced and spectrally indistinguishable from the preceding context. Therefore, their presence can be ambiguous, and they may disappear perceptually depending on the rate of surrounding speech. Two experiments are presented examining production and perception of reduced tokens of for and for a in spontaneous speech. Experiment 1 investigates the distributions of several acoustic features of for and for a. The results suggest that the distributions of for and for a overlap substantially, both in terms of temporal and spectral characteristics. Experiment 2 examines perception of these same tokens when the context speaking rate differs. The perceptibility of the function word a varies as a function of this context speaking rate. These results demonstrate that substantial ambiguity exists in the original quote from Armstrong, and that this ambiguity may be understood through context speaking rate. PMID:27603209

  14. Revisiting Neil Armstrongs Moon-Landing Quote: Implications for Speech Perception, Function Word Reduction, and Acoustic Ambiguity

    PubMed Central

    Baese-Berk, Melissa M.; Dilley, Laura C.; Schmidt, Stephanie; Morrill, Tuuli H.; Pitt, Mark A.

    2016-01-01

    Neil Armstrong insisted that his quote upon landing on the moon was misheard, and that he had said one small step for a man, instead of one small step for man. What he said is unclear in part because function words like a can be reduced and spectrally indistinguishable from the preceding context. Therefore, their presence can be ambiguous, and they may disappear perceptually depending on the rate of surrounding speech. Two experiments are presented examining production and perception of reduced tokens of for and for a in spontaneous speech. Experiment 1 investigates the distributions of several acoustic features of for and for a. The results suggest that the distributions of for and for a overlap substantially, both in terms of temporal and spectral characteristics. Experiment 2 examines perception of these same tokens when the context speaking rate differs. The perceptibility of the function word a varies as a function of this context speaking rate. These results demonstrate that substantial ambiguity exists in the original quote from Armstrong, and that this ambiguity may be understood through context speaking rate. PMID:27603209

  15. Revisiting Neil Armstrongs Moon-Landing Quote: Implications for Speech Perception, Function Word Reduction, and Acoustic Ambiguity.

    PubMed

    Baese-Berk, Melissa M; Dilley, Laura C; Schmidt, Stephanie; Morrill, Tuuli H; Pitt, Mark A

    2016-01-01

    Neil Armstrong insisted that his quote upon landing on the moon was misheard, and that he had said one small step for a man, instead of one small step for man. What he said is unclear in part because function words like a can be reduced and spectrally indistinguishable from the preceding context. Therefore, their presence can be ambiguous, and they may disappear perceptually depending on the rate of surrounding speech. Two experiments are presented examining production and perception of reduced tokens of for and for a in spontaneous speech. Experiment 1 investigates the distributions of several acoustic features of for and for a. The results suggest that the distributions of for and for a overlap substantially, both in terms of temporal and spectral characteristics. Experiment 2 examines perception of these same tokens when the context speaking rate differs. The perceptibility of the function word a varies as a function of this context speaking rate. These results demonstrate that substantial ambiguity exists in the original quote from Armstrong, and that this ambiguity may be understood through context speaking rate.

  16. An ambiguity of information content and error in an ill-posed satellite inversion

    NASA Astrophysics Data System (ADS)

    Koner, Prabhat

    According to Rodgers (2000, stochastic approach), the averaging kernel (AK) is the representational matrix to understand the information content in a scholastic inversion. On the other hand, in deterministic approach this is referred to as model resolution matrix (MRM, Menke 1989). The analysis of AK/MRM can only give some understanding of how much regularization is imposed on the inverse problem. The trace of the AK/MRM matrix, which is the so-called degree of freedom from signal (DFS; stochastic) or degree of freedom in retrieval (DFR; deterministic). There are no physical/mathematical explanations in the literature: why the trace of the matrix is a valid form to calculate this quantity? We will present an ambiguity between information and error using a real life problem of SST retrieval from GOES13. The stochastic information content calculation is based on the linear assumption. The validity of such mathematics in satellite inversion will be questioned because it is based on the nonlinear radiative transfer and ill-conditioned inverse problems. References: Menke, W., 1989: Geophysical data analysis: discrete inverse theory. San Diego academic press. Rodgers, C.D., 2000: Inverse methods for atmospheric soundings: theory and practice. Singapore :World Scientific.

  17. Ambiguity in running spectral index with an extra light field during inflation

    SciTech Connect

    Kohri, Kazunori; Matsuda, Tomohiro E-mail: matsuda@sit.ac.jp

    2015-02-01

    At the beginning of inflation there could be extra dynamical scalar fields that will soon disappear (become static) before the end of inflation. In the light of multi-field inflation, those extra degrees of freedom may alter the time-dependence of the original spectrum of the curvature perturbation. It is possible to remove such fields introducing extra number of e-foldings prior to 0N{sub e}∼ 6, however such extra e-foldings may make the trans-Planckian problem worse due to the Lyth bound. We show that such extra scalar fields can change the running of the spectral index to give correction of ± 0.01 without adding significant contribution to the spectral index. The corrections to the spectral index (and the amplitude) could be important in considering global behavior of the corrected spectrum, although they can be neglected in the estimation of the spectrum and its spectral index at the pivot scale. The ambiguity in the running of the spectral index, which could be due to such fields, can be used to nullify tension between BICEP2 and Planck experiments.

  18. A Columbine study: giving voice, hearing meaning.

    PubMed

    Mears, Carolyn Lunsford

    2008-01-01

    On a quiet spring morning, the 20th of April 1999, Columbine High School emerged from relative anonymity as a typical suburban high school and became internationally recognized as a symbol of school violence and tragic loss. As a parent whose child was in the school at the time of the attack, I struggled to make sense of the tragedy. I decided to conduct research into the experience as a way to learn lessons that might help others exposed to community-wide trauma in the future. Through modified oral history interviews of other Columbine parents in combination with other qualitative research strategies, I collected and studied stories of the events of that day and the years following. An unexpected by-product emerged from the study, for it seemed that I was not only learning about crisis response and trauma care but also offering a means for parents to gain comfort in reflecting on their own experience. This paper describes the distinct approach that I employed to create a gateway to understanding this experience. It does not explicate the findings of the Columbine study but instead explores the potential for positive outcomes for those who, by giving voice to their stories, can connect to a deeper appreciation for their own experience. PMID:19256102

  19. A Columbine study: giving voice, hearing meaning.

    PubMed

    Mears, Carolyn Lunsford

    2008-01-01

    On a quiet spring morning, the 20th of April 1999, Columbine High School emerged from relative anonymity as a typical suburban high school and became internationally recognized as a symbol of school violence and tragic loss. As a parent whose child was in the school at the time of the attack, I struggled to make sense of the tragedy. I decided to conduct research into the experience as a way to learn lessons that might help others exposed to community-wide trauma in the future. Through modified oral history interviews of other Columbine parents in combination with other qualitative research strategies, I collected and studied stories of the events of that day and the years following. An unexpected by-product emerged from the study, for it seemed that I was not only learning about crisis response and trauma care but also offering a means for parents to gain comfort in reflecting on their own experience. This paper describes the distinct approach that I employed to create a gateway to understanding this experience. It does not explicate the findings of the Columbine study but instead explores the potential for positive outcomes for those who, by giving voice to their stories, can connect to a deeper appreciation for their own experience.

  20. Still Giving Thanks for Good Health

    NASA Technical Reports Server (NTRS)

    2005-01-01

    [figure removed for brevity, see original site] Click on the image for Still Giving Thanks for Good Health (QTVR)

    NASA's Mars Exploration Rover Spirit took this full-circle panorama of the region near 'Husband Hill' (the peak just to the left of center) over the Thanksgiving holiday, before ascending farther. Both the Spirit and Opportunity rovers are still going strong, more than a year after landing on Mars.

    This 360-degree view combines 243 images taken by Spirit's panoramic camera over several martian days, or sols, from sol 318 (Nov. 24, 2004) to sol 325 (Dec. 2, 2004). It is an approximately true-color rendering generated from images taken through the camera's 750-, 530-, and 480-nanometer filters. The view is presented here in a cylindrical projection with geometric seam correction.

    Spirit is now driving up the slope of Husband Hill along a path about one-quarter of the way from the left side of this mosaic.

  1. A physical-model-based, field-wise and self-contained algorithm for removing directional ambiguities of ocean surface winds retrieved from scatterometer measurements

    NASA Astrophysics Data System (ADS)

    Kim, Young-Joon

    2000-09-01

    An algorithm is introduced to remove the directional ambiguities in ocean surface winds measured by scatterometers, which requires scatterometer data only. It is based on two versions of PBL (planetary boundary layer) models and a low-pass filter. A pressure field is first derived from the median-filtered scatterometer winds, is then noise-filtered, and is finally converted back to the winds, respectively, by an inverted PBL model, a smoothing algorithm, and a PBL model. The derived wind field is used to remove the directional ambiguities in the scatterometer data. This new algorithm is applied to Hurricane Eugene and produces results comparable to those from the current standard ambiguity removal algorithm for NASA/JPL SeaWinds project, which requires external numerical weather forecast/analyses data.

  2. The ambiguous role of the paraeducator in the general physical education environment.

    PubMed

    Bryan, Rebecca R; McCubbin, Jeffrey A; van der Mars, Hans

    2013-04-01

    The use of paraeducators has increased as a main mechanism to include more students with disabilities in the public schools in the U.S. Although the utilization of paraeducators is intended to be a supportive service delivery option, many concerns and challenges have resulted. The purpose of this study was to examine the role of the paraeducator in the general physical education environment from the perspectives of special education, physical education, and adapted physical education teachers and paraeducators. Data were collected from a phenomenological approach using questionnaires, interviews, and observations. Results indicate concerns about the clarity of the role of the paraeducator in physical education. Emerging themes include elastic definitions of student protection and teacher backup, contradictory expectations and mixed acceptance, and paraeducators' role ambiguity. Findings regarding the role of the paraeducator are essential in determining both best practice and legal policy for the appropriate utilization of paraeducators in physical education.

  3. Midwestern Millennial University Students' Tolerance for Ambiguity in a Period of Complex World Conflicts

    ERIC Educational Resources Information Center

    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…

  4. In the Face of Uncertainty: A Twin Study of Ambiguous Information, Anxiety and Depression in Children

    ERIC Educational Resources Information Center

    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,…

  5. Exploring the Relationship between Tolerance of Ambiguity of EFL Learners and Their Vocabulary Knowledge

    ERIC Educational Resources Information Center

    Basöz, Tutku

    2015-01-01

    Learning a new language is akin to exploring an unknown land as ambiguous situations are prevalent in language learning. Ambiguity tolerance, which can hinder or facilitate language learning, is considered as an important learning style. The purpose of the present study was to understand how tolerant/intolerant EFL learners are of foreign language…

  6. Race as a Mediating Factor between Tolerance for Ambiguity and Empathy.

    ERIC Educational Resources Information Center

    Hartman, Bruce W.; And Others

    1980-01-01

    Black and white subjects (N=80) of both sexes completed the Budner Intolerance of Ambiguity Scale and Hogan Scale for Empathy. Data revealed limited support for the hypothesis that tolerance for ambiguity and empathy was positively correlated for White students of both sexes and not correlated for Blacks. (NRB)

  7. An Analysis of the Associations between Ambiguity Tolerance and EFL Reading Strategy Awareness

    ERIC Educational Resources Information Center

    Kamran, Saeedeh Karbalaee; Maftoon, Parviz

    2012-01-01

    The current study is an attempt to investigate whether any statistically significant relationship existed between Iranian EFL learners' ambiguity tolerance (AT) and their reading strategy use. To this end, three instruments of Survey of Reading Strategy (Mokhtari & Sheorey, 2002), Second Language Ambiguity Tolerance Scale (Ely, 1995), and a…

  8. Medical Student and Junior Doctors' Tolerance of Ambiguity: Development of a New Scale

    ERIC Educational Resources Information Center

    Hancock, Jason; Roberts, Martin; Monrouxe, Lynn; Mattick, Karen

    2015-01-01

    The practice of medicine involves inherent ambiguity, arising from limitations of knowledge, diagnostic problems, complexities of treatment and outcome and unpredictability of patient response. Research into doctors' tolerance of ambiguity is hampered by poor conceptual clarity and inadequate measurement scales. We aimed to create and pilot a…

  9. Implicit and Explicit Understanding of Ambiguous Figures by Adolescents with Autism Spectrum Disorder

    ERIC Educational Resources Information Center

    Allen, Melissa L.; Chambers, Alison

    2011-01-01

    Children with autism spectrum disorder (ASD) can process both interpretations of an ambiguous figure (e.g. rabbit/duck) when told about the ambiguity, however they tend not to do so spontaneously. Here we show that although adolescents with ASD can explicitly experience such "reversals", implicit measures suggest they are conceptually processing…

  10. Children's Gender Orientation and Perceptions of Female, Male, and Gender-Ambiguous Animal Characters.

    ERIC Educational Resources Information Center

    Karniol, Rachel; Reichman, Shiri; Fund, Liat

    2000-01-01

    Examined the effects of preadolescents' gender orientation on social perception of animal characters whose gender was clearly female, male, or gender-ambiguous. Children's gender orientation did not influence perceptions of the gender of characters that were clearly female and male, but did influence perceptions of ambiguous characters. Children's…

  11. The Relationship between Tolerance of Ambiguity and Stereotyping: Implications for BSW Education

    ERIC Educational Resources Information Center

    Valutis, Stephanie A.

    2015-01-01

    Ambiguity tolerance and intolerance can influence one's professional practice. The study of such influences remains sparse within the social work literature. Behaviors that reduce uncertainty, including categorizing or stereotyping, are used by those who feel discomfort in ambiguous situations. This study explores explore the relationship between…

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

    ERIC Educational Resources Information Center

    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…

  13. Ambiguous Belonging and the Challenge of Inclusion: Parent Perspectives on School Membership

    ERIC Educational Resources Information Center

    Scorgie, Kate

    2015-01-01

    Boundary ambiguity occurs when members of a family are confused or uncertain regarding roles, responsibilities and subsystem configurations within the family. Research suggests that perception of boundary ambiguity is associated with family stress despite internal and external resource availability. It has been suggested that research on family…

  14. Ambiguous Loss Research, Theory, and Practice: Reflections after 9-11

    ERIC Educational Resources Information Center

    Boss, Pauline

    2004-01-01

    This article contains an overview of three decades of research, theory development, and clinical application about ambiguous loss. Although the work includes both physical and psychological types of ambiguous loss, the focus is the aftermath of 9-11 (September 11, 2001) when the World Trade Center collapsed following terrorist attacks. On the…

  15. As Far As Words Go: Activities for Understanding Ambiguous Language and Humor, Revised Edition

    ERIC Educational Resources Information Center

    Spector, Cecile Cyrul

    2009-01-01

    Understanding ambiguous words, phrases, and sentences is an important part of reading well, communicating skillfully, and enjoying humor based on word play. With this seven-unit activity book--filled with creative, ready-to-use activities based on jokes and puns--students will learn how to decipher the language ambiguities they encounter inside…

  16. On the Impact of L2 Speech Rhythm on Syntactic Ambiguity Resolution

    ERIC Educational Resources Information Center

    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…

  17. Perceived Role Conflict, Role Ambiguity, and Burnout among Special Education Teachers.

    ERIC Educational Resources Information Center

    Crane, Stephen J.; Iwanicki, Edward F.

    1986-01-01

    The study examined the relationship of role conflict and role ambiguity to teacher burnout among 443 urban special education teachers. Role conflict and ambiguity explained a significant amount of variance in feelings of emotional exhaustion and depersonalization. While perceived burnout among teachers was moderate, the level varied significantly…

  18. Role Conflict and Ambiguity as Predictors of Job Satisfaction in High School Counselors

    ERIC Educational Resources Information Center

    Cervoni, Annemarie; DeLucia-Waack, Janice

    2011-01-01

    The purpose of this study was to examine the relationship between role conflict and role ambiguity, and percentage of time spent on ASCA recommended duties (counseling, coordination, consultation, and large group guidance); and job satisfaction of high school counselors. The Role Conflict and Role Ambiguity Scale and the Job Descriptive Index were…

  19. Comprehension of Ambiguous and Other Polysemous Utterances: Presented in Written Mode.

    ERIC Educational Resources Information Center

    Brause, Rita S.

    Designed to assess comprehension of written ambiguous and polysemous structures, this instrument is a series of written statements that include varying degrees and types of ambiguity. In the first part of the test students are asked to identify (from a choice of three) semantically acceptable paraphrases for an initial sentence. Then students must…

  20. The Kindergarten Path Effect Revisited: Children's Use of Context in Processing Structural Ambiguities

    ERIC Educational Resources Information Center

    Weighall, Anna R.

    2008-01-01

    Research with adults has shown that ambiguous spoken sentences are resolved efficiently, exploiting multiple cues--including referential context--to select the intended meaning. Paradoxically, children appear to be insensitive to referential cues when resolving ambiguous sentences, relying instead on statistical properties intrinsic to the…

  1. Early Morphological Processing Is Sensitive to Morphemic Meanings: Evidence from Processing Ambiguous Morphemes

    ERIC Educational Resources Information Center

    Tsang, Yiu-Kei; Chen, Hsuan-Chih

    2013-01-01

    In three priming experiments, we investigated whether the meanings of ambiguous morphemes were activated during word recognition. Using a meaning generation task, Experiment 1 demonstrated that the dominant meaning of individually presented ambiguous morphemes was reported more often than did other less frequent meanings. Also, participants tended…

  2. Exploiting Degrees of Inflectional Ambiguity: Stem Form and the Time Course of Morphological Processing

    ERIC Educational Resources Information Center

    Jarvikivi, Juhani; Pyykkonen, Pirita; Niemi, Jussi

    2009-01-01

    The authors compared sublexical and supralexical approaches to morphological processing with unambiguous and ambiguous inflected words and words with ambiguous stems in 3 masked and unmasked priming experiments in Finnish. Experiment 1 showed equal facilitation for all prime types with a short 60-ms stimulus onset asynchrony (SOA) but significant…

  3. Meaning Dominance and Semantic Context in the Processing of Lexical Ambiguity.

    ERIC Educational Resources Information Center

    Simpson, Greg B.

    1981-01-01

    Describes two experiments on the processing of ambiguous words: one involving lexical decisions for words related to dominant or subordinate meanings of homograph primes, the other involving ambiguous words ending sentences that bias the homographs at varying degrees. Concludes that dominance and context contribute independently to processing of…

  4. Transfer in L3 Sentence Processing: Evidence from Relative Clause Attachment Ambiguities

    ERIC Educational Resources Information Center

    Rah, Anne

    2010-01-01

    The present study investigates transfer effects in two groups of German learners of French for ambiguous relative clause (RC) constructions. The first learner group had started to learn French before English, whereas the second group had started to learn English before French. The RC attachment ambiguity is interesting to study possible transfer…

  5. A Multiple-Channel Model of Task-Dependent Ambiguity Resolution in Sentence Comprehension

    ERIC Educational Resources Information Center

    Logacev, Pavel; Vasishth, Shravan

    2016-01-01

    Traxler, Pickering, and Clifton (1998) found that ambiguous sentences are read faster than their unambiguous counterparts. This so-called "ambiguity advantage" has presented a major challenge to classical theories of human sentence comprehension (parsing) because its most prominent explanation, in the form of the unrestricted race model…

  6. Structural Ambiguities and Written Advertisements: An Inventory of Tools for More Resourceful Advertisements in English.

    ERIC Educational Resources Information Center

    Oaks, Dallin D.

    1995-01-01

    Discusses some types of writing tasks, such as advertising, in which a writer might want to create ambiguous wordplays. States that a more conscious understanding of the structure of a language could make the generation of structural ambiguities easier. Examines some structural features of English that could prove useful to advertisers who wish to…

  7. Ambiguity Tolerance: Adolescents' Responses to Uncertainty in Life. Research Report, September 1996-December 1997.

    ERIC Educational Resources Information Center

    Stoycheva, Katya

    Adolescents today have to live with incoherence for longer periods than before, and that makes ambiguity tolerance a socially significant personality dimension. Studies of the development of ambiguity tolerance in adolescents are reported. The pilot study, "Adaptation of MAT-50 for Use with Bulgarian Population," involves translation and…

  8. A Model of Ambiguity and Vagueness in Clinical Practice Guideline Recommendations

    PubMed Central

    Codish, Shlomi; Shiffman, Richard N.

    2005-01-01

    Ambiguity and vagueness in clinical practice guidelines reduce the likelihood of clinician adherence. They lead to inconsistent interpretation and, in turn, to inappropriate practice variation and medical errors. Resolving ambiguity and vagueness is an essential step in the computerized implementation of clinical practice guidelines. Successful resolution of ambiguity and vagueness requires an understanding of their characteristics, yet ambiguity and vagueness have not been differentiated, classified and described in medical context. In this paper, we propose a tri-axial model to describe ambiguity and vagueness in clinical practice guidelines: differentiation of true ambiguity from vagueness, classification of ambiguity and vagueness, intentionality and components involved. Our goals in introducing this model are: (a) to provide guidance to guideline authors to enable them to reduce inadvertent use of ambiguous or vague language, (b) to improve transparency when vague language is used deliberately and (c) to create a framework for the development of tools to apply the model during authoring and implementation of clinical practice guidelines. PMID:16779019

  9. VNTR fingerprinting of Kluyveromyces marxianus strains WT, 7-1, and 8-1 by using different primer types to give best results in PCR and on electrophorese gel in order to find differentiation of the DNA of the yeast strains.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Using mutagenized Kluyveromyces marxianus strains (WT, 7-1, 8-1) we wish to find out the variable numbered tandem repeats (VNTR) of each of the DNA strains from the different mutagenized K. marxianus strains. To do this we used Phusion HF Buffer Pack to try and give a clear picture of the VNTR by u...

  10. Semiconductor Bolometers Give Background-Limited Performance

    NASA Technical Reports Server (NTRS)

    Goebel, John; McMurray, Robert

    2006-01-01

    Semiconductor bolometers that are capable of detecting electromagnetic radiation over most or all of the infrared spectrum and that give background-limited performance at operating temperatures from 20 to 300 K have been invented. The term background-limited performance as applied to a bolometer, thermopile, or other infrared detector signifies that the ability to detect infrared signals that originate outside the detector is limited primarily by thermal noise attributable to the background radiation generated external to the bolometer. The signal-to-noise ratios and detectivities of the bolometers and thermopiles available prior to this invention have been lower than those needed for background-limited performance by factors of about 100 and 10, respectively. Like other electrically resistive bolometers, a device according to the invention exhibits an increase in electrical resistance when heated by infrared radiation. Depending on whether the device is operated under the customary constant- current or constant-voltage bias, the increase in electrical resistance can be measured in terms of an increase in voltage across the device or a decrease in current through the device, respectively. In the case of a semiconductor bolometer, it is necessary to filter out visible and shorter-wavelength light that could induce photoconductivity and thereby counteract all or part of the desired infrared- induced increase in resistance. The basic semiconductor material of a bolometer according to the invention is preferably silicon doped with one or more of a number of elements, each of which confers a different variable temperature coefficient of resistance. Suitable dopants include In, Ga, S, Se, Te, B, Al, As, P, and Sb. The concentration of dopant preferably lies in the range between 0.1 and 1,000 parts per billion.

  11. Spaceborne Hybrid Quad-Pol SAR Range Ambiguity Analysis and Simulations

    NASA Astrophysics Data System (ADS)

    Yang, Shilin; Li, Yang; Zhang, Jingjing; Hong, Wen

    2014-11-01

    The higher levels of range ambiguities in the cross-polarized measurement channels are the primary limitations for the matched quad-pol (e.g., HH, VV, VH, and HV) spaceborne synthetic aperture radar (SAR) systems. These ambiguities severely constrain the useful range of incident angles and the swath widths particularly at larger incidence. Adopting hybridpolarimetric architecture can remarkably reduce these ambiguities. In this paper, we analyse and develop the expression of range ambiguity to signal ratio (RASR) in the hybrid-polarimetric architecture. Simulations are made to testify this novel architecture’s advantage in the improvement of range ambiguities. The system operating parameters are derived from NASA’s DESDynl mission. In addition, we used the second order moments of polarimetric covariance matrices to depict target or the environment which are more precisely.

  12. Finding meaning in art: preferred levels of ambiguity in art appreciation.

    PubMed

    Jakesch, Martina; Leder, Helmut

    2009-11-01

    Uncertainty is typically not desirable in everyday experiences, but uncertainty in the form of ambiguity may be a defining feature of aesthetic experiences of modern art. In this study, we examined different hypotheses concerning the quantity and quality of information appreciated in art. Artworks were shown together with auditorily presented statements. We tested whether the amount of information, the amount of matching information, or the proportion of matching to nonmatching statements apparent in a picture (levels of ambiguity) affect liking and interestingness. Only the levels of ambiguity predicted differences in the two dependent variables. These findings reveal that ambiguity is an important determinant of aesthetic appreciation and that a certain level of ambiguity is appreciable.

  13. Ambiguity tolerance in organizations: definitional clarification and perspectives on future research

    PubMed Central

    McLain, David L.; Kefallonitis, Efstathios; Armani, Kimberly

    2015-01-01

    Ambiguity tolerance is an increasingly popular subject for study in a wide variety of fields. The definition of ambiguity tolerance has changed since its inception, and accompanying that change are changes in measurement and the research questions that interest researchers. There is a wealth of opportunity for research related to ambiguity tolerance and recent advances in neuroscience, measurement, trait research, perception, problem solving, and other fields highlight areas of interest and point to issues that need further attention. The future of ambiguity tolerance research is promising and it is expected that future studies will yield new insights into individual differences in reactions to the complex, unfamiliar, confusing, indeterminate, and incomplete stimuli that fall within the conceptual domain of ambiguity. PMID:25972818

  14. On the ambiguity of the reaction rate constants in multivariate curve resolution for reversible first-order reaction systems.

    PubMed

    Schröder, Henning; Sawall, Mathias; Kubis, Christoph; Selent, Detlef; Hess, Dieter; Franke, Robert; Börner, Armin; Neymeyr, Klaus

    2016-07-13

    If for a chemical reaction with a known reaction mechanism the concentration profiles are accessible only for certain species, e.g. only for the main product, then often the reaction rate constants cannot uniquely be determined from the concentration data. This is a well-known fact which includes the so-called slow-fast ambiguity. This work combines the question of unique or non-unique reaction rate constants with factor analytic methods of chemometrics. The idea is to reduce the rotational ambiguity of pure component factorizations by considering only those concentration factors which are possible solutions of the kinetic equations for a properly adapted set of reaction rate constants. The resulting set of reaction rate constants corresponds to those solutions of the rate equations which appear as feasible factors in a pure component factorization. The new analysis of the ambiguity of reaction rate constants extends recent research activities on the Area of Feasible Solutions (AFS). The consistency with a given chemical reaction scheme is shown to be a valuable tool in order to reduce the AFS. The new methods are applied to model and experimental data. PMID:27237834

  15. On the ambiguity of the reaction rate constants in multivariate curve resolution for reversible first-order reaction systems.

    PubMed

    Schröder, Henning; Sawall, Mathias; Kubis, Christoph; Selent, Detlef; Hess, Dieter; Franke, Robert; Börner, Armin; Neymeyr, Klaus

    2016-07-13

    If for a chemical reaction with a known reaction mechanism the concentration profiles are accessible only for certain species, e.g. only for the main product, then often the reaction rate constants cannot uniquely be determined from the concentration data. This is a well-known fact which includes the so-called slow-fast ambiguity. This work combines the question of unique or non-unique reaction rate constants with factor analytic methods of chemometrics. The idea is to reduce the rotational ambiguity of pure component factorizations by considering only those concentration factors which are possible solutions of the kinetic equations for a properly adapted set of reaction rate constants. The resulting set of reaction rate constants corresponds to those solutions of the rate equations which appear as feasible factors in a pure component factorization. The new analysis of the ambiguity of reaction rate constants extends recent research activities on the Area of Feasible Solutions (AFS). The consistency with a given chemical reaction scheme is shown to be a valuable tool in order to reduce the AFS. The new methods are applied to model and experimental data.

  16. Source estimation with surface-related multiples—fast ambiguity-resolved seismic imaging

    NASA Astrophysics Data System (ADS)

    Tu, Ning; Aravkin, Aleksandr; van Leeuwen, Tristan; Lin, Tim; Herrmann, Felix J.

    2016-06-01

    We address the problem of obtaining a reliable seismic image without prior knowledge of the source wavelet, especially from data that contain strong surface-related multiples. Conventional reverse-time migration requires prior knowledge of the source wavelet, which is either technically or computationally challenging to accurately determine; inaccurate estimates of the source wavelet can result in seriously degraded reverse-time migrated images, and therefore wrong geological interpretations. To solve this problem, we present a `wavelet-free' imaging procedure that simultaneously inverts for the source wavelet and the seismic image, by tightly integrating source estimation into a fast least-squares imaging framework, namely compressive imaging, given a reasonably accurate background velocity model. However, this joint inversion problem is difficult to solve as it is plagued with local minima and the ambiguity with respect to amplitude scalings because of the multiplicative, and therefore nonlinear, appearance of the source wavelet in the otherwise linear formalism. We have found a way to solve this nonlinear joint-inversion problem using a technique called variable projection, and a way to overcome the scaling ambiguity by including surface-related multiples in our imaging procedure following recent developments in surface-related multiple prediction by sparse inversion. As a result, we obtain without prior knowledge of the source wavelet high-resolution seismic images, comparable in quality to images obtained assuming the true source wavelet is known. By leveraging the computationally efficient compressive-imaging methodology, these results are obtained at affordable computational costs compared with conventional processing work flows that include surface-related multiple removal and reverse-time migration.

  17. Investigating Emotional Top Down Modulation of Ambiguous Faces by Single Pulse TMS on Early Visual Cortices.

    PubMed

    Yaple, Zachary A; Vakhrushev, Roman

    2016-01-01

    Top-down processing is a mechanism in which memory, context and expectation are used to perceive stimuli. For this study we investigated how emotion content, induced by music mood, influences perception of happy and sad emoticons. Using single pulse TMS we stimulated right occipital face area (rOFA), primary visual cortex (V1) and vertex while subjects performed a face-detection task and listened to happy and sad music. At baseline, incongruent audio-visual pairings decreased performance, demonstrating dependence of emotion while perceiving ambiguous faces. However, performance of face identification decreased during rOFA stimulation regardless of emotional content. No effects were found between Cz and V1 stimulation. These results suggest that while rOFA is important for processing faces regardless of emotion, V1 stimulation had no effect. Our findings suggest that early visual cortex activity may not integrate emotional auditory information with visual information during emotion top-down modulation of faces. PMID:27445674

  18. Brutality under cover of ambiguity: activating, perpetuating, and deactivating covert retributivism.

    PubMed

    Fincher, Katrina M; Tetlock, Philip E

    2015-05-01

    Five studies tested four hypotheses on the drivers of punitive judgments. Study 1 showed that people imposed covertly retributivist physical punishments on extreme norm violators when they could plausibly deny that is what they were doing (attributional ambiguity). Studies 2 and 3 showed that covert retributivism could be suppressed by subtle accountability manipulations that cue people to the possibility that they might be under scrutiny. Studies 4 and 5 showed how covert retributivism can become self-sustaining by biasing the lessons people learn from experience. Covert retributivists did not scale back punitiveness in response to feedback that the justice system makes false-conviction errors but they did ramp up punitiveness in response to feedback that the system makes false-acquittal errors. Taken together, the results underscore the paradoxical nature of covert retributivism: It is easily activated by plausible deniability and persistent in the face of false-conviction feedback but also easily deactivated by minimalist forms of accountability.

  19. Perceptions of ambiguously unpleasant interracial interactions: a structural equation modeling approach.

    PubMed

    Marino, Teresa L; Negy, Charles; Hammons, Mary E; McKinney, Cliff; Asberg, Kia

    2007-11-01

    Despite a general consensus in the United States that overtly racist acts are unacceptable, many ambiguous situations in everyday life raise questions of whether racism has influenced a person's behavior in an interracial encounter. The authors of the present study sought to (a) examine simultaneously an array of variables thought to be related to perceived racism and (b) investigate how the contribution of these variables may differ with respect to the asymmetry hypothesis, which suggests that acts of discrimination from a dominant person toward a subordinate person will be viewed as more biased than if the situation were reversed. The authors used a dual structural equation modeling approach. Results indicated that ethnic identity significantly predicted perceived racism. In addition, the extent to which cognitive interpretation style significantly predicted perceived racism depended on the ethnicity of participants involved in the interaction.

  20. Investigating Emotional Top Down Modulation of Ambiguous Faces by Single Pulse TMS on Early Visual Cortices

    PubMed Central

    Yaple, Zachary A.; Vakhrushev, Roman

    2016-01-01

    Top-down processing is a mechanism in which memory, context and expectation are used to perceive stimuli. For this study we investigated how emotion content, induced by music mood, influences perception of happy and sad emoticons. Using single pulse TMS we stimulated right occipital face area (rOFA), primary visual cortex (V1) and vertex while subjects performed a face-detection task and listened to happy and sad music. At baseline, incongruent audio-visual pairings decreased performance, demonstrating dependence of emotion while perceiving ambiguous faces. However, performance of face identification decreased during rOFA stimulation regardless of emotional content. No effects were found between Cz and V1 stimulation. These results suggest that while rOFA is important for processing faces regardless of emotion, V1 stimulation had no effect. Our findings suggest that early visual cortex activity may not integrate emotional auditory information with visual information during emotion top-down modulation of faces. PMID:27445674

  1. Direct Speaker Gaze Promotes Trust in Truth-Ambiguous Statements.

    PubMed

    Kreysa, Helene; Kessler, Luise; Schweinberger, Stefan R

    2016-01-01

    A speaker's gaze behaviour can provide perceivers with a multitude of cues which are relevant for communication, thus constituting an important non-verbal interaction channel. The present study investigated whether direct eye gaze of a speaker affects the likelihood of listeners believing truth-ambiguous statements. Participants were presented with videos in which a speaker produced such statements with either direct or averted gaze. The statements were selected through a rating study to ensure that participants were unlikely to know a-priori whether they were true or not (e.g., "sniffer dogs cannot smell the difference between identical twins"). Participants indicated in a forced-choice task whether or not they believed each statement. We found that participants were more likely to believe statements by a speaker looking at them directly, compared to a speaker with averted gaze. Moreover, when participants disagreed with a statement, they were slower to do so when the statement was uttered with direct (compared to averted) gaze, suggesting that the process of rejecting a statement as untrue may be inhibited when that statement is accompanied by direct gaze. PMID:27643789

  2. Ambiguous Capture: Collaborative Capitalism and the Meningitis Vaccine Project

    PubMed Central

    Graham, Janice

    2016-01-01

    ABSTRACT The primary health care approach advanced at Alma Ata to address social determinants of health was replaced by selective health care a year later at Bellagio. Subsequently, immunization was endorsed as a cost-effective technical intervention to combat targeted infectious diseases. Multilateral efforts to collaborate on immunization as a universal public health good ambiguously capture the interests of the world’s governments as well as private, public, and not-for-profit institutions. Global assemblages of scientists, governments, industry and nongovernmental organizations now work in public-private partnerships to develop and make essential vaccines accessible, with vaccines marketed as single fix solutions for global health. Drawing from ethnographic fieldwork in France and Burkina Faso that followed the development, regulation, and implementation of the group A meningococcal conjugate vaccine for sub-Saharan Africa, in this article I describe events during and after the development of MenAfriVac. A technological success narrative steeped in collaborative capitalist rhetoric disguises neglected health care systems. PMID:27027575

  3. NICE's selective application of differential discounting: ambiguous, inconsistent, and unjustified.

    PubMed

    O'Mahony, James F; Paulden, Mike

    2014-07-01

    The National Institute for Health and Clinical Excellence (NICE) recently recommended differential discounting of costs and health effects in the economic appraisal of health care interventions in certain circumstances. The recommendation was published in an amendment to NICE's Guide to the Methods of Technology Appraisal. The amendment states that differential discounting should be applied where "treatment effects are both substantial in restoring health and sustained over a very long period (normally at least 30 years)." Renewed interest in differential discounting from NICE is welcome; however, the recommendation's selective application of differential discounting raises a number of concerns. The stated criteria for applying differential discounting are ambiguous. The rationale for the selective application of differential discounting has not been articulated by NICE and is questionable. The selective application of differential discounting leads to several inconsistencies, the most concerning of which is the lower valuation of health gains for those with less than 30 years remaining life expectancy, which can be interpreted as age discrimination. Furthermore, the discount rates chosen by NICE do not appear to be informed by recent advances in the theoretical understanding of differential discounting. NICE's apparent motivation for recommending differential discounting was to ensure a favorable cost-effectiveness ratio for a pediatric oncology drug. While flexibility may be appropriate to allow some interventions that exceed conventional cost-effectiveness thresholds to be adopted, the selective adjustment of appraisal methods is problematic and without justification.

  4. Disambiguating ambiguous motion perception: what are the cues?

    PubMed Central

    Piedimonte, Alessandro; Woods, Adam J.; Chatterjee, Anjan

    2015-01-01

    Motion perception is a fundamental feature of the human visual system. As part of our daily life we often have to determine the direction of motion, even in ambiguous (AMB) situations. These situations force us to rely on exogenous cues, such as other environmental motion, and endogenous cues, such as our own actions, or previously learned experiences. In three experiments, we asked participants to report the direction of an AMB motion display, while manipulating exogenous and endogenous sources of information. Specifically, in all three experiments the exogenous information was represented by another motion cue while the endogenous cue was represented, respectively, by movement execution, movement planning, or a learned association about the motion display. Participants were consistently biased by less AMB motion cues in the environment when reporting the AMB target direction. In the absence of less AMB exogenous motion information, participants were biased by their motor movements and even the planning of such movements. However, when participants learned a specific association about the target motion, this acquired endogenous knowledge countered exogenous motion cues in biasing participants’ perception. Taken together, our findings demonstrate that we disambiguate AMB motion using different sources of exogenous and endogenous cues, and that learned associations may be particularly salient in countering the effects of environmental cues. PMID:26217257

  5. Priming effects on the perceived grouping of ambiguous dot patterns.

    PubMed

    Kurylo, Daniel D; Bukhari, Farhan

    2015-09-01

    For ambiguous stimuli, complex dynamics guide processes of perceptual grouping. Previous studies have suggested two opposing effects on grouping that are produced by the preliminary stimulus state: one that enhances grouping towards the existing structure, and another that opposes this structure. To examine effects of the preliminary state on grouping directly, measurements were made of perceived grouping of dot patterns that followed a visual prime. Three stimuli were presented in sequence: prime, target, and mask. Targets were composed of an evenly spaced dot grid in which grouping was established by similarity in luminance. Subjects indicated the dominant perceived grouping. The prime either corresponded to or opposed the prevailing organization of the target. Contrary to the hypothesis, solid-line primes biased grouping away from the structure of the prime, even when the prevailing organization of dot patterns strongly favored the primes' structure. This effect occurred, although to a lesser extent, when primes did not occupy the same location of targets, but were presented in a marginal area surrounding the grid. Priming effects did not occur for primes constructed of dot patterns. Effects found here may be attributed to a forward masking effect by primes, which more effectively disrupts grouping of patterns matched to the prime. Effects may also be attributed to a type of pattern contrast, in which a grouped pattern dissimilar to primes gains salience. For the pattern contrast model, the partial activation of multiple grouped configurations is compared to the pattern of the solid-line primes. PMID:25281427

  6. Direct Speaker Gaze Promotes Trust in Truth-Ambiguous Statements

    PubMed Central

    Kessler, Luise; Schweinberger, Stefan R.

    2016-01-01

    A speaker’s gaze behaviour can provide perceivers with a multitude of cues which are relevant for communication, thus constituting an important non-verbal interaction channel. The present study investigated whether direct eye gaze of a speaker affects the likelihood of listeners believing truth-ambiguous statements. Participants were presented with videos in which a speaker produced such statements with either direct or averted gaze. The statements were selected through a rating study to ensure that participants were unlikely to know a-priori whether they were true or not (e.g., “sniffer dogs cannot smell the difference between identical twins”). Participants indicated in a forced-choice task whether or not they believed each statement. We found that participants were more likely to believe statements by a speaker looking at them directly, compared to a speaker with averted gaze. Moreover, when participants disagreed with a statement, they were slower to do so when the statement was uttered with direct (compared to averted) gaze, suggesting that the process of rejecting a statement as untrue may be inhibited when that statement is accompanied by direct gaze. PMID:27643789

  7. Priming effects on the perceived grouping of ambiguous dot patterns.

    PubMed

    Kurylo, Daniel D; Bukhari, Farhan

    2015-09-01

    For ambiguous stimuli, complex dynamics guide processes of perceptual grouping. Previous studies have suggested two opposing effects on grouping that are produced by the preliminary stimulus state: one that enhances grouping towards the existing structure, and another that opposes this structure. To examine effects of the preliminary state on grouping directly, measurements were made of perceived grouping of dot patterns that followed a visual prime. Three stimuli were presented in sequence: prime, target, and mask. Targets were composed of an evenly spaced dot grid in which grouping was established by similarity in luminance. Subjects indicated the dominant perceived grouping. The prime either corresponded to or opposed the prevailing organization of the target. Contrary to the hypothesis, solid-line primes biased grouping away from the structure of the prime, even when the prevailing organization of dot patterns strongly favored the primes' structure. This effect occurred, although to a lesser extent, when primes did not occupy the same location of targets, but were presented in a marginal area surrounding the grid. Priming effects did not occur for primes constructed of dot patterns. Effects found here may be attributed to a forward masking effect by primes, which more effectively disrupts grouping of patterns matched to the prime. Effects may also be attributed to a type of pattern contrast, in which a grouped pattern dissimilar to primes gains salience. For the pattern contrast model, the partial activation of multiple grouped configurations is compared to the pattern of the solid-line primes.

  8. Ambiguous Capture: Collaborative Capitalism and the Meningitis Vaccine Project.

    PubMed

    Graham, Janice

    2016-01-01

    The primary health care approach advanced at Alma Ata to address social determinants of health was replaced by selective health care a year later at Bellagio. Subsequently, immunization was endorsed as a cost-effective technical intervention to combat targeted infectious diseases. Multilateral efforts to collaborate on immunization as a universal public health good ambiguously capture the interests of the world's governments as well as private, public, and not-for-profit institutions. Global assemblages of scientists, governments, industry and nongovernmental organizations now work in public-private partnerships to develop and make essential vaccines accessible, with vaccines marketed as single fix solutions for global health. Drawing from ethnographic fieldwork in France and Burkina Faso that followed the development, regulation, and implementation of the group A meningococcal conjugate vaccine for sub-Saharan Africa, in this article I describe events during and after the development of MenAfriVac. A technological success narrative steeped in collaborative capitalist rhetoric disguises neglected health care systems. PMID:27027575

  9. Ambiguous Capture: Collaborative Capitalism and the Meningitis Vaccine Project.

    PubMed

    Graham, Janice

    2016-01-01

    The primary health care approach advanced at Alma Ata to address social determinants of health was replaced by selective health care a year later at Bellagio. Subsequently, immunization was endorsed as a cost-effective technical intervention to combat targeted infectious diseases. Multilateral efforts to collaborate on immunization as a universal public health good ambiguously capture the interests of the world's governments as well as private, public, and not-for-profit institutions. Global assemblages of scientists, governments, industry and nongovernmental organizations now work in public-private partnerships to develop and make essential vaccines accessible, with vaccines marketed as single fix solutions for global health. Drawing from ethnographic fieldwork in France and Burkina Faso that followed the development, regulation, and implementation of the group A meningococcal conjugate vaccine for sub-Saharan Africa, in this article I describe events during and after the development of MenAfriVac. A technological success narrative steeped in collaborative capitalist rhetoric disguises neglected health care systems.

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

    PubMed

    Clément, Gilles; Wood, Scott J

    2014-01-01

    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.

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

    PubMed

    Clément, Gilles; Wood, Scott J

    2014-01-01

    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. PMID:25354042

  12. Abnormal N400 Responses But Intact Differential Hemispheric Processing of Ambiguity in Schizophrenia

    PubMed Central

    Salisbury, Dean F

    2009-01-01

    Disordered thinking in schizophrenia may be a consequence of the selection of conceptual associates of dominant meanings of ambiguous words despite contextual information suggesting subordinate meanings are more appropriate. Previous work using short sentences showed a large N400 event-related potential to subordinate meaning associates and a behavioral semantic bias, but results were variable. The current experiment used word pairs to simplify the procedure and to less tax memory maintenance. Furthermore, hemispheric responses were compared, as evidence suggests the left hemisphere may select dominant meanings, while the right hemisphere may keep all possible meanings active. Subjects indicated whether two words (CUE, TARGET) were related. The CUE, presented for 1 second, could be an ambiguous or an unambiguous noun, and the TARGET, presented 1.25 seconds after the onset of the CUE, was a dominant or subordinate associate, or a related or an unrelated word, respectively. The N400-effect was calculated from difference waveforms over 400-600 msec. Groups (23 schizophrenia, 25 matched controls) showed significantly different N400-effects to the words (group x word, p =.04). Controls showed a graded response, with dominant < subordinate < unrelated. Schizophrenia patients showed the largest N400-effect to subordinate associates, with less activity to dominant meaning associates and unrelated words. Both groups showed a right hemisphere distribution to unrelated words and substantial left hemisphere activation to subordinate associates (word x hemisphere, p <.001). These data support a semantic bias in schizophrenia. They also demonstrate a special role of the right hemisphere in maintaining broad homograph meaning hierarchies. This hemispheric specialization appears to be intact in schizophrenia. PMID:20161687

  13. Analysis of genetic code ambiguity arising from nematode-specific misacylated tRNAs.

    PubMed

    Hamashima, Kiyofumi; Mori, Masaru; Andachi, Yoshiki; Tomita, Masaru; Kohara, Yuji; Kanai, Akio

    2015-01-01

    The faithful translation of the genetic code requires the highly accurate aminoacylation of transfer RNAs (tRNAs). However, it has been shown that nematode-specific V-arm-containing tRNAs (nev-tRNAs) are misacylated with leucine in vitro in a manner that transgresses the genetic code. nev-tRNA(Gly) (CCC) and nev-tRNA(Ile) (UAU), which are the major nev-tRNA isotypes, could theoretically decode the glycine (GGG) codon and isoleucine (AUA) codon as leucine, causing GGG and AUA codon ambiguity in nematode cells. To test this hypothesis, we investigated the functionality of nev-tRNAs and their impact on the proteome of Caenorhabditis elegans. Analysis of the nucleotide sequences in the 3' end regions of the nev-tRNAs showed that they had matured correctly, with the addition of CCA, which is a crucial posttranscriptional modification required for tRNA aminoacylation. The nuclear export of nev-tRNAs was confirmed with an analysis of their subcellular localization. These results show that nev-tRNAs are processed to their mature forms like common tRNAs and are available for translation. However, a whole-cell proteome analysis found no detectable level of nev-tRNA-induced mistranslation in C. elegans cells, suggesting that the genetic code is not ambiguous, at least under normal growth conditions. Our findings indicate that the translational fidelity of the nematode genetic code is strictly maintained, contrary to our expectations, although deviant tRNAs with misacylation properties are highly conserved in the nematode genome. PMID:25602944

  14. Abnormal N400 Responses But Intact Differential Hemispheric Processing of Ambiguity in Schizophrenia.

    PubMed

    Salisbury, Dean F

    2010-05-01

    Disordered thinking in schizophrenia may be a consequence of the selection of conceptual associates of dominant meanings of ambiguous words despite contextual information suggesting subordinate meanings are more appropriate. Previous work using short sentences showed a large N400 event-related potential to subordinate meaning associates and a behavioral semantic bias, but results were variable. The current experiment used word pairs to simplify the procedure and to less tax memory maintenance. Furthermore, hemispheric responses were compared, as evidence suggests the left hemisphere may select dominant meanings, while the right hemisphere may keep all possible meanings active. Subjects indicated whether two words (CUE, TARGET) were related. The CUE, presented for 1 second, could be an ambiguous or an unambiguous noun, and the TARGET, presented 1.25 seconds after the onset of the CUE, was a dominant or subordinate associate, or a related or an unrelated word, respectively. The N400-effect was calculated from difference waveforms over 400-600 msec. Groups (23 schizophrenia, 25 matched controls) showed significantly different N400-effects to the words (group x word, p =.04). Controls showed a graded response, with dominant < subordinate < unrelated. Schizophrenia patients showed the largest N400-effect to subordinate associates, with less activity to dominant meaning associates and unrelated words. Both groups showed a right hemisphere distribution to unrelated words and substantial left hemisphere activation to subordinate associates (word x hemisphere, p <.001). These data support a semantic bias in schizophrenia. They also demonstrate a special role of the right hemisphere in maintaining broad homograph meaning hierarchies. This hemispheric specialization appears to be intact in schizophrenia. PMID:20161687

  15. Giving Pediatric Immunizations the Priority They Deserve.

    ERIC Educational Resources Information Center

    Shalala, Donna E.

    1993-01-01

    Stresses the need for increased federal, state, and local support for child immunizations resulting from the alarming increases in the incidence of rubella and other infectious diseases, and endorses the Standards for Pediatric Immunization Practices recently published in the "Journal of the American Medical Association." (MDM)

  16. Give Better Feedback on Engineering Drawings

    ERIC Educational Resources Information Center

    Cobb, Robert, Jr.; Graham, Tony; Kapur, Arjun; Rhodes, Craig; Blackwell, Ellinor

    2005-01-01

    Most, if not all, systems have a mechanism that collects information to facilitate monitoring performance. This information is primarily used to modify the system to make it more efficient in performing desired tasks and, thus, attaining desired results. Similar to electrical, mechanical, or hydraulic systems, the feedback mechanism in an…

  17. NSF Gives Aid to Poorly Funded States.

    ERIC Educational Resources Information Center

    Physics Today, 1983

    1983-01-01

    Experimental Program to Stimulate Competitive Research (EPSCOR), a National Science Foundation-funded program is in the third year of its five-year grants to scientists in five states. Program objectives, financial support (including cost-sharing by states), state programs resulting from EPSCOR, and EPSCOR achievements are discussed. (JN)

  18. Processing ambiguous Spanish se in a minimal chain.

    PubMed

    Meseguer, Enrique; Acuña-Fariña, Carlos; Carreiras, Manuel

    2009-04-01

    The recovery of pieces of information that are not linguistically expressed is a constant feature of the process of language comprehension. In the processing literature, such missing information is generally referred to as "gaps". Usually, one resolves gaps by finding "fillers" in either the sentence or the context. For instance, in Peter seemed to be upset, Peter is really the subject of being upset but appears as surface subject of seems. Sometimes constituents move, leaving gaps behind. Various Romance languages such as Spanish or Italian have a grammatical particle se/si, which, as it is extremely ambiguous, licenses different sorts of gaps. In Spanish, se can encode at least reflexive, impersonal, and passive meanings. In an eye-tracking experiment we contrast reflexive structures containing postverbal subjects with impersonal structures with no subjects (GAP se vendó apresuradamente el corredor/"the runner bandaged himself hurriedly" vs. GAP se vendó apresuradamente al corridor/"(someone) bandaged the runner hurriedly"). In a second manipulation we contrast the presence of an extra argument with se-passives (GAP se vendó el tobillo el corredor/"the runner bandaged his ankle" vs. GAP se vendó el tobillo al corridor/"the runner's ankle was bandaged"). Our comparisons involve contrasting standard transitive structures with nonstandard word order (postverbal subject and a preverbal subject gap) against inherently complex and less habitual structures such as impersonals (with no subject) or se-passives (with subjects in canonical object position). We evaluate the minimal chain principle (de Vincenzi, 1991), according to which displacement is costly because it entails complex (derivational) "chains" that must be undone before phrasal packaging can commence. We show the minimal chain principle to be essentially correct when contrasting more complex but more frequent structures with less complex but less frequent structures. A noteworthy feature of this research

  19. Using uniformat and gene[rate] to Analyze Data with Ambiguities in Population Genetics

    PubMed Central

    Nunes, José Manuel

    2015-01-01

    Some genetic systems frequently present ambiguous data that cannot be straightforwardly analyzed with common methods of population genetics. Two possibilities arise to analyze such data: one is the arbitrary simplification of the data and the other is the development of methods adapted to such ambiguous data. In this article, we present an attempt at such a development, the uniformat grammar and The gene[rate] tools, highlighting the specific aspects and the adaptations required to analyze ambiguous nominal data in population genetics. PMID:26917942

  20. Depositional history gives clue to Hackberry production

    SciTech Connect

    Ewing, T.E.; Reed, R.S.

    1985-02-01

    The discovery of additional stratigraphic reservoirs within the already-producing Hackberry sandstones of southeast Texas can be enhanced by a thorough understanding of the complexities of both overall channel geometry and the internal heterogeneity of these sands. This geologic assessment locates major submarine channels, describes the geometries of the sandstone bodies, details the evolution of the Hackberry depositional system and discusses resulting hydrocarbon distribution.

  1. Is it time to give up?

    USGS Publications Warehouse

    Buddemeier, R.W.

    2001-01-01

    The world's coral reefs show rapid decline as a result of environmental change. Coral reef communities and organisms are stressed, potentially mortally, by (1) rising temperature, (2) rising atmospheric/surface ocean CO2 levels, (3) rising human populations, and (4) local aspects of climate change other than temperature. Further increase in all of these stressors is certain; the future rates and magnitudes of items 1-3 can be estimated with confidence to be substantially greater than changes in the recent past.

  2. Compliment-Giving among Filipino College Students: An Exploratory Study.

    ERIC Educational Resources Information Center

    Mojica, Leonisa A.

    2002-01-01

    Studies syntactic patterns in compliment-giving among Filipino students at six universities in Manila. Finds differences between male and female student compliment-giving patterns, such as greater frequency of female compliment-giving. Also finds sex differences in the purpose of compliment-giving. (PKP)

  3. Giving students the run of sprinting models

    NASA Astrophysics Data System (ADS)

    Heck, André; Ellermeijer, Ton

    2009-11-01

    A biomechanical study of sprinting is an interesting task for students who have a background in mechanics and calculus. These students can work with real data and do practical investigations similar to the way sports scientists do research. Student research activities are viable when the students are familiar with tools to collect and work with data from sensors and video recordings and with modeling tools for comparing simulation and experimental results. This article describes a multipurpose system, named COACH, that offers a versatile integrated set of tools for learning, doing, and teaching mathematics and science in a computer-based inquiry approach. Automated tracking of reference points and correction of perspective distortion in videos, state-of-the-art algorithms for data smoothing and numerical differentiation, and graphical system dynamics based modeling are some of the built-in techniques that are suitable for motion analysis. Their implementation and their application in student activities involving models of running are discussed.

  4. Landfill mining: Giving garbage a second chance

    SciTech Connect

    Cobb, C.C.; Ruckstuhl, K. )

    1988-08-01

    Some communities face the problems of lack of landfill space and lack of landfill cover dirt. In some cases, existing landfills may be mined to reclaim dirt for use as cover material and to recover space for reuse. Such mining also has the potential of recovering recyclables and incinerator fuels. Machinery to reclaim refuse deposits, and their heterogeneous composted ingredients, was successfully tested at two Florida landfills in June 1987. One of the Florida mining tests, at the Collier County landfill near the city of Naples, had goals of demonstrating an economical mechanical system to separate the depository's ingredients into usable or redisposable components, and to see if the method could enable the county to avoid the expenses associated with permanent closure of a full landfill. This paper describes the history of the Collier County landfill, the equipment and feasibility test, economics, the monitoring of odors, landfill gas, and heavy metals, and results of the test.

  5. Optimum blending gives best pool octane

    SciTech Connect

    Morris, W.E.

    1986-01-20

    Optimum blending of gasoline components can increase the pool octane by 0.1 to 0.5 numbers. To achieve the optimum octane blending scheme, accurate octane blending values must be obtained. These blending values can be developed from an interaction blending study or from generalized predicted interaction coefficients. Many refiners are blending in a non-optimum fashion so that there are some cheap octanes available for the taking by simply changing to an optimum blending scheme. A study of 1984 gasoline compositions indicated that many refiners were blending in a non-optimum fashion and that ''pool octane'' could have been increased almost 0.5 octane. The term pool octane usually refers to the weighted average octane of all of the gasoline components. It can be calculated by multiplying the octane of each component by its fraction of the pool and adding the results. If the components are blended into two or more grades, a second pool octane could be calculated by multiplying the octane of each grade, before any lead antiknock addition, by its fraction of the total pool. The second pool octane will differ from the first because the components do not blend linearly. The octane of a 50:50 blend of two components may be higher or lower than the average of the octanes of the two components.

  6. Role conflict and ambiguity of CEOs in international joint ventures: a transaction cost perspective.

    PubMed

    Gong, Y; Shenkar, O; Luo, Y; Nyaw, M K

    2001-08-01

    Insights from transaction cost economics were used to study the boundary conditions underlying the role conflict and ambiguity of 265 CEOs in Chinese-based international joint ventures. Role conflict and ambiguity were lower when the contract between parents was more complete. Contract completeness fully mediated the effects of parent objective gap and parent formalization on role ambiguity but only partially so in the case of role conflict. Role conflict was lower when the foreign parent was dominant in the venture but higher when the local parent was dominant. Role conflict and ambiguity were inversely related to cultural distance. Neither construct had a detrimental effect on international joint venture performance. Implications for role theory are discussed. PMID:11519659

  7. Role conflict and ambiguity of CEOs in international joint ventures: a transaction cost perspective.

    PubMed

    Gong, Y; Shenkar, O; Luo, Y; Nyaw, M K

    2001-08-01

    Insights from transaction cost economics were used to study the boundary conditions underlying the role conflict and ambiguity of 265 CEOs in Chinese-based international joint ventures. Role conflict and ambiguity were lower when the contract between parents was more complete. Contract completeness fully mediated the effects of parent objective gap and parent formalization on role ambiguity but only partially so in the case of role conflict. Role conflict was lower when the foreign parent was dominant in the venture but higher when the local parent was dominant. Role conflict and ambiguity were inversely related to cultural distance. Neither construct had a detrimental effect on international joint venture performance. Implications for role theory are discussed.

  8. Identification and definition of lexically ambiguous words in statistics by tutors and students

    NASA Astrophysics Data System (ADS)

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

    2013-10-01

    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 are also collected at the beginning and end of a semester of introductory statistics study, in a complex design taking account of multiple tutors and multiple words in multiple contexts. Tutor perceptions and actual student difficulties at the beginning of a semester are compared. The lexical ambiguity associated with the word 'significance' is shown to be evident in students even after completing an introductory statistics course.

  9. Old Star's "Rebirth" Gives Astronomers Surprises

    NASA Astrophysics Data System (ADS)

    2005-04-01

    Astronomers using the National Science Foundation's Very Large Array (VLA) radio telescope are taking advantage of a once-in-a-lifetime opportunity to watch an old star suddenly stir back into new activity after coming to the end of its normal life. Their surprising results have forced them to change their ideas of how such an old, white dwarf star can re-ignite its nuclear furnace for one final blast of energy. Sakurai's Object Radio/Optical Images of Sakurai's Object: Color image shows nebula ejected thousands of years ago. Contours indicate radio emission. Inset is Hubble Space Telescope image, with contours indicating radio emission; this inset shows just the central part of the region. CREDIT: Hajduk et al., NRAO/AUI/NSF, ESO, StSci, NASA Computer simulations had predicted a series of events that would follow such a re-ignition of fusion reactions, but the star didn't follow the script -- events moved 100 times more quickly than the simulations predicted. "We've now produced a new theoretical model of how this process works, and the VLA observations have provided the first evidence supporting our new model," said Albert Zijlstra, of the University of Manchester in the United Kingdom. Zijlstra and his colleagues presented their findings in the April 8 issue of the journal Science. The astronomers studied a star known as V4334 Sgr, in the constellation Sagittarius. It is better known as "Sakurai's Object," after Japanese amateur astronomer Yukio Sakurai, who discovered it on February 20, 1996, when it suddenly burst into new brightness. At first, astronomers thought the outburst was a common nova explosion, but further study showed that Sakurai's Object was anything but common. The star is an old white dwarf that had run out of hydrogen fuel for nuclear fusion reactions in its core. Astronomers believe that some such stars can undergo a final burst of fusion in a shell of helium that surrounds a core of heavier nuclei such as carbon and oxygen. However, the

  10. Testosterone supplementation: what and how to give.

    PubMed

    Jockenhövel, F

    2003-09-01

    in American patients, who have benefited from its availability for almost 3 years. Furthermore, in phase II and III clinical studies, the intramuscular injection of 1000 mg testosterone undecanoate every 12-15 weeks has led to extremely stable serum testosterone levels for a prolonged period of time and has resulted in excellent efficacy. It is very likely in the future that these products will be the mainstay of testosterone supplementation. Whereas the indication for testosterone substitution for men with classical forms of hypogonadism is unequivocal, the use of testosterone in men with age-associated hypogonadism is less uniformly accepted. Yet, the few studies addressing this question indicate that men with testosterone serum levels below the lower normal limit for young adult men and with lack of energy, libido, depressed mood and osteoporosis may benefit from testosterone supplementation. However, it should be kept in mind that the experience documented in studies is limited. Nevertheless, serious side-effects, especially in regard to the prostate, did not occur, with the longest study extending over 3 years. PMID:14628500

  11. The contribution of BDS triple-frequency signals to ambiguity resolution

    NASA Astrophysics Data System (ADS)

    Dai, Zhiqiang

    2014-05-01

    At present, it is a trend to introduce multi-frequency technique to global navigation satellite system (GNSS). The new generations of GNSS all transmit three or more carriers, for example, the modernizing GPS introduce the L5 signal, besides the existing L1 and L2 signals, the upcoming European Galileo system is designed to transmit L1, E6, E5B, E5A signals, and the developing Chinese BeiDou navigation satellite system (BDS) is transmitting B1, B2, and B3 signals. The extra frequencies are expected to benefit the precise GNSS data processing, especially for carrier phase ambiguity resolution (AR). By the end of 2012, the Chinese BDS has achieved the second phase, realizing regional service for Asian-Pacific area. More than 16 BDS satellites are transmitting triple-frequency signals, which is much more than GPS and Galileo. How much do the triple-frequency signals contribute to AR? To answer this question, we collected the simultaneous BDS triple-frequency observations for baselines with different lengths. These simultaneous observations were double differenced for each baseline to resolve the baseline components and the double-differenced (DD) ambiguities. We resolved the DD ambiguities in two steps. Firstly, the extra-wide-lane (EWL) and wide-lane (WL) ambiguities were resolved in the geometry-free observation model. Secondly, ambiguities of the original carrier-phase observations were estimated in the geometry-based model along with the baseline components, in which, the fixed EWL and WL ambiguities are used to constraint the original carrier-phase ambiguities. Since the AR performance is strongly dependent on the baseline length, we investigated the AR success rate and time to first fix for each baseline, and evaluated the AR improvement brought by the triple-frequency signals. Keywords: GNSS, BDS, Triple-frequency ambiguity resolution, AR

  12. The interaction of patient race, provider bias, and clinical ambiguity on pain management decisions

    PubMed Central

    Hirsh, Adam T.; Hollingshead, Nicole A.; Ashburn-Nardo, Leslie; Kroenke, Kurt

    2015-01-01

    Although racial disparities in pain care are widely reported, much remains to be known about the role of provider and contextual factors. We used computer-simulated patients to examine the influence of patient race, provider racial bias, and clinical ambiguity on pain decisions. One hundred twenty nine medical residents/fellows made assessment (pain intensity) and treatment (opioid and non-opioid analgesics) decisions for 12 virtual patients with acute pain. Race (Black/White) and clinical ambiguity (high/low) were manipulated across vignettes. Participants completed the Implicit Association Test and feeling thermometers, which assess implicit and explicit racial biases, respectively. Individual- and group-level analyses indicated that race and ambiguity had an interactive effect on providers’ decisions, such that decisions varied as a function of ambiguity for White but not Black patients. Individual differences across providers were observed for the effect of race and ambiguity on decisions; however providers’ implicit and explicit biases did not account for this variability. These data highlight the complexity of racial disparities and suggest that differences in care between White and Black patients are, in part, attributable to the nature (i.e., ambiguity) of the clinical scenario. The current study suggests that interventions to reduce disparities should differentially target patient, provider, and contextual factors. PMID:25828370

  13. Attitude Toward Ambiguity: Empirically Robust Factors in Self-Report Personality Scales.

    PubMed

    Lauriola, Marco; Foschi, Renato; Mosca, Oriana; Weller, Joshua

    2016-06-01

    Two studies were conducted to examine the factor structure of attitude toward ambiguity, a broad personality construct that refers to personal reactions to perceived ambiguous stimuli in a variety of context and situations. Using samples from two countries, Study 1 mapped the hierarchical structure of 133 items from seven tolerance-intolerance of ambiguity scales (N = 360, Italy; N = 306, United States). Three major factors-Discomfort with Ambiguity, Moral Absolutism/Splitting, and Need for Complexity and Novelty-were recovered in each country with high replicability coefficients across samples. In Study 2 (N = 405, Italian community sample; N =366, English native speakers sample), we carried out a confirmatory analysis on selected factor markers. A bifactor model had an acceptable fit for each sample and reached the construct-level invariance for general and group factors. Convergent validity with related traits was assessed in both studies. We conclude that attitude toward ambiguity can be best represented a multidimensional construct involving affective (Discomfort with Ambiguity), cognitive (Moral Absolutism/Splitting), and epistemic (Need for Complexity and Novelty) components.

  14. Ambiguity: A new way of thinking about responses to climate change.

    PubMed

    Fleming, A; Howden, S M

    2016-11-15

    Diversity, interdisciplinarity and transdisciplinarity are now recognized as vital to tackling wicked problems such as those presented by a changing climate (Nature editorial 2015, Ledford 2015; Dick et al., 2016). Including diverse disciplines in science projects enables a range of different views which often facilitate the creation of innovative solutions. Supporting multiple views and options requires a different way of working beyond traditional reductionist approaches to science, communication and decision-making. To embrace diversity in scientific project teams in order to tackle complex, integrated and urgent issues but to expect singular and linear pathways forward is paradoxical. Much has been written about the need for the scientific community to embrace uncertainty (e.g. Popper, Lempert & Bankes 2005; Lempert et al., 2004; Nelson, Howden & Hayman 2013; Bammer & Smithson 2008). We argue that this in itself will not suffice, and that there is also a need to embrace ambiguity in certain situations. Thus, in this article we explore: (1) what ambiguity is, including the benefits it can offer to climate adaptation in particular, using existing approaches to ambiguity in the arts and humanities as examples (2), we discuss practical meanings of ambiguity in relation to climate change, (3) we propose possible next steps for bringing ambiguity into interdisciplinary practice, and (4) we identify some challenges and necessary preconditions to successfully and appropriately embracing ambiguity.

  15. Attitude Toward Ambiguity: Empirically Robust Factors in Self-Report Personality Scales.

    PubMed

    Lauriola, Marco; Foschi, Renato; Mosca, Oriana; Weller, Joshua

    2016-06-01

    Two studies were conducted to examine the factor structure of attitude toward ambiguity, a broad personality construct that refers to personal reactions to perceived ambiguous stimuli in a variety of context and situations. Using samples from two countries, Study 1 mapped the hierarchical structure of 133 items from seven tolerance-intolerance of ambiguity scales (N = 360, Italy; N = 306, United States). Three major factors-Discomfort with Ambiguity, Moral Absolutism/Splitting, and Need for Complexity and Novelty-were recovered in each country with high replicability coefficients across samples. In Study 2 (N = 405, Italian community sample; N =366, English native speakers sample), we carried out a confirmatory analysis on selected factor markers. A bifactor model had an acceptable fit for each sample and reached the construct-level invariance for general and group factors. Convergent validity with related traits was assessed in both studies. We conclude that attitude toward ambiguity can be best represented a multidimensional construct involving affective (Discomfort with Ambiguity), cognitive (Moral Absolutism/Splitting), and epistemic (Need for Complexity and Novelty) components. PMID:25818603

  16. Ambiguity: A new way of thinking about responses to climate change.

    PubMed

    Fleming, A; Howden, S M

    2016-11-15

    Diversity, interdisciplinarity and transdisciplinarity are now recognized as vital to tackling wicked problems such as those presented by a changing climate (Nature editorial 2015, Ledford 2015; Dick et al., 2016). Including diverse disciplines in science projects enables a range of different views which often facilitate the creation of innovative solutions. Supporting multiple views and options requires a different way of working beyond traditional reductionist approaches to science, communication and decision-making. To embrace diversity in scientific project teams in order to tackle complex, integrated and urgent issues but to expect singular and linear pathways forward is paradoxical. Much has been written about the need for the scientific community to embrace uncertainty (e.g. Popper, Lempert & Bankes 2005; Lempert et al., 2004; Nelson, Howden & Hayman 2013; Bammer & Smithson 2008). We argue that this in itself will not suffice, and that there is also a need to embrace ambiguity in certain situations. Thus, in this article we explore: (1) what ambiguity is, including the benefits it can offer to climate adaptation in particular, using existing approaches to ambiguity in the arts and humanities as examples (2), we discuss practical meanings of ambiguity in relation to climate change, (3) we propose possible next steps for bringing ambiguity into interdisciplinary practice, and (4) we identify some challenges and necessary preconditions to successfully and appropriately embracing ambiguity. PMID:27486065

  17. Greater Emotional Gain from Giving in Older Adults: Age-Related Positivity Bias in Charitable Giving.

    PubMed

    Bjälkebring, Pär; Västfjäll, Daniel; Dickert, Stephan; Slovic, Paul

    2016-01-01

    Older adults have been shown to avoid negative and prefer positive information to a higher extent than younger adults. This positivity bias influences their information processing as well as decision-making. We investigate age-related positivity bias in charitable giving in two studies. In Study 1 we examine motivational factors in monetary donations, while Study 2 focuses on the emotional effect of actual monetary donations. In Study 1, participants (n = 353, age range 20-74 years) were asked to rate their affect toward a person in need and then state how much money they would be willing to donate to help this person. In Study 2, participants (n = 108, age range 19-89) were asked to rate their affect toward a donation made a few days prior. Regression analysis was used to investigate whether or not the positivity bias influences the relationship between affect and donations. In Study 1, we found that older adults felt more sympathy and compassion and were less motivated by negative affect when compared to younger adults, who were motivated by both negative and positive affect. In Study 2, we found that the level of positive emotional reactions from monetary donations was higher in older participants compared to younger participants. We find support for an age-related positivity bias in charitable giving. This is true for motivation to make a future donation, as well as affective thinking about a previous donation. We conclude that older adults draw more positive affect from both the planning and outcome of monetary donations and hence benefit more from engaging in monetary charity than their younger counterparts. PMID:27378966

  18. Greater Emotional Gain from Giving in Older Adults: Age-Related Positivity Bias in Charitable Giving

    PubMed Central

    Bjälkebring, Pär; Västfjäll, Daniel; Dickert, Stephan; Slovic, Paul

    2016-01-01

    Older adults have been shown to avoid negative and prefer positive information to a higher extent than younger adults. This positivity bias influences their information processing as well as decision-making. We investigate age-related positivity bias in charitable giving in two studies. In Study 1 we examine motivational factors in monetary donations, while Study 2 focuses on the emotional effect of actual monetary donations. In Study 1, participants (n = 353, age range 20–74 years) were asked to rate their affect toward a person in need and then state how much money they would be willing to donate to help this person. In Study 2, participants (n = 108, age range 19–89) were asked to rate their affect toward a donation made a few days prior. Regression analysis was used to investigate whether or not the positivity bias influences the relationship between affect and donations. In Study 1, we found that older adults felt more sympathy and compassion and were less motivated by negative affect when compared to younger adults, who were motivated by both negative and positive affect. In Study 2, we found that the level of positive emotional reactions from monetary donations was higher in older participants compared to younger participants. We find support for an age-related positivity bias in charitable giving. This is true for motivation to make a future donation, as well as affective thinking about a previous donation. We conclude that older adults draw more positive affect from both the planning and outcome of monetary donations and hence benefit more from engaging in monetary charity than their younger counterparts. PMID:27378966

  19. The Advantage of Ambiguity? Enhanced Neural Responses to Multi-Stable Percepts Correlate with the Degree of Perceived Instability

    PubMed Central

    Dyson, Benjamin J.

    2011-01-01

    Artwork can often pique the interest of the viewer or listener as a result of the ambiguity or instability contained within it. Our engagement with uncertain sensory experiences might have its origins in early cortical responses, in that perceptually unstable stimuli might preclude neural habituation and maintain activity in early sensory areas. To assess this idea, participants engaged with an ambiguous visual stimulus wherein two squares alternated with one another, in terms of simultaneously opposing vertical and horizontal locations relative to fixation (i.e., stroboscopic alternating motion; von Schiller, 1933). At each trial, participants were invited to interpret the movement of the squares in one of five ways: traditional vertical or horizontal motion, novel clockwise or counter-clockwise motion, and, a free-view condition in which participants were encouraged to switch the direction of motion as often as possible. Behavioral reports of perceptual stability showed clockwise and counter-clockwise motion to possess an intermediate level of stability compared to relatively stable vertical and horizontal motion, and, relatively unstable motion perceived during free-view conditions. Early visual evoked components recorded at parietal–occipital sites such as C1, P1, and N1 modulated as a function of visual intention. Both at a group and individual level, increased perceptual instability was related to increased negativity in all three of these early visual neural responses. Engagement with increasingly ambiguous input may partly result from the underlying exaggerated neural response to it. The study underscores the utility of combining neuroelectric recording with the presentation of perceptually multi-stable yet physically identical stimuli, in revealing brain activity associated with the purely internal process of interpreting and appreciating the sensory world that surrounds us. PMID:21897812

  20. Various Ambiguities in Re-constructing Laser Pulse Parameters

    NASA Technical Reports Server (NTRS)

    Roychoudhuri, Chandrasekhar; Prasa, Narasimha

    2006-01-01

    each other without interacting with (scattering from) each other. Thus the interpretation of the superposition phenomenon of multiple fields on detectors should not be lumped under the mysterious "wave-particle duality" philosophy. The phenomenon of superposition can be understood better when we focus on the actual process experienced by the detecting dipoles when allowed by QM rules, they respond to and sum all the induced stimulations due to all the superposed fields followed by the proportionate energy absorption giving rise to the fringes we observe. We will present various experimental results to illustrate our arguments. Our position is that such detector behavior driven interpretations rather than the generally implied field-field interaction driven explanations, will help us better understand the ultimate nature of light and hence invent better and newer devices and instruments.

  1. 27 CFR 29.51 - Failure to give notice; penalty.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false Failure to give notice... BUREAU, DEPARTMENT OF THE TREASURY LIQUORS STILLS AND MISCELLANEOUS REGULATIONS Stills § 29.51 Failure to give notice; penalty. Failure to give notice of manufacture of still or notice of setup of still...

  2. A hierarchical linear modeling analysis of working memory and implicit prosody in the resolution of adjunct attachment ambiguity.

    PubMed

    Traxler, Matthew J

    2009-10-01

    An eye-movement monitoring experiment investigated readers' response to temporarily ambiguous sentences. The sentences were ambiguous because a relative clause could attach to one of two preceding nouns. Semantic information disambiguated the sentences. Working memory considerations predict an overall preference for the second of the two nouns, as does the late closure principle (Frazier, On comprehending sentences: Syntactic parsing strategies. Ph.D. dissertation, University of Connecticut. West Bend, IN: Indiana University Linguistics Club, 1979). Previous studies assessing preferences for such items have obtained mixed results. On-line assessments show that working memory affects the degree of preference for the first noun, with lower capacity readers having a greater preference for the second noun (Felser et al., Language Acquisition: A Journal of Developmental Linguistics, 11, 127-163, 2003; Traxler, Memory & Cognition, 35, 1107-1121, 2007). Off-line assessments indicate the opposite pattern of preferences when the test sentences are displayed on a single line (Swets et al., Journal of Experimental Psychology: General, 136, 64-81, 2007). However, when implicit prosody is manipulated by displaying the sentences with a break between the second noun and the relative clause, the off-line assessments indicate that readers prefer to attach the relative clause to the first noun. In this experiment, readers' undertook a working memory assessment and then read test sentences that were displayed across two lines, with a break appearing after the second noun and before the relative clause. The eye-tracking data indicated an overall preference to attach the relative clause to the first noun, and there was little indication that working memory moderated the degree of preference for this configuration. Hence, it appears that readers' implicit prosodic contours rapidly affect resolution of adjunct attachment ambiguities.

  3. Reducing the ambiguity of karst aquifer models by pattern matching of flow and transport on catchment scale

    NASA Astrophysics Data System (ADS)

    Oehlmann, S.; Geyer, T.; Licha, T.; Sauter, M.

    2015-02-01

    Assessing the hydraulic parameters of karst aquifers is a challenge due to their high degree of heterogeneity. The unknown parameter field generally leads to a high ambiguity for flow and transport calibration in numerical models of karst aquifers. In this study, a distributed numerical model was built for the simulation of groundwater flow and solute transport in a highly heterogeneous karst aquifer in south-western Germany. Therefore, an interface for the simulation of solute transport in one-dimensional pipes was implemented into the software COMSOL Multiphysics® and coupled to the three-dimensional solute transport interface for continuum domains. For reducing model ambiguity, the simulation was matched for steady-state conditions to the hydraulic head distribution in the model area, the spring discharge of several springs and the transport velocities of two tracer tests. Furthermore, other measured parameters such as the hydraulic conductivity of the fissured matrix and the maximal karst conduit volume were available for model calibration. Parameter studies were performed for several karst conduit geometries to analyse the influence of the respective geometric and hydraulic parameters and develop a calibration approach in a large-scale heterogeneous karst system. Results show that it is possible not only to derive a consistent flow and transport model for a 150 km2 karst area but also to combine the use of groundwater flow and transport parameters thereby greatly reducing model ambiguity. The approach provides basic information about the conduit network not accessible for direct geometric measurements. The conduit network volume for the main karst spring in the study area could be narrowed down to approximately 100 000 m3.

  4. Reducing the ambiguity of karst aquifer models by pattern matching of flow and transport on catchment scale

    NASA Astrophysics Data System (ADS)

    Oehlmann, S.; Geyer, T.; Licha, T.; Sauter, M.

    2014-08-01

    Assessing the hydraulic parameters of karst aquifers is a challenge due to their high degree of heterogeneity. The unknown parameter field generally leads to a high ambiguity for flow and transport calibration in numerical models of karst aquifers. In this study, a distributive numerical model was built for the simulation of groundwater flow and solute transport in a highly heterogeneous karst aquifer in south western Germany. Therefore, an interface for the simulation of solute transport in one-dimensional pipes was implemented into the software Comsol Multiphysics® and coupled to the three-dimensional solute transport interface for continuum domains. For reducing model ambiguity, the simulation was matched for steady-state conditions to the hydraulic head distribution in the model area, the spring discharge of several springs and the transport velocities of two tracer tests. Furthermore, other measured parameters such as the hydraulic conductivity of the fissured matrix and the maximal karst conduit volume were available for model calibration. Parameter studies were performed for several karst conduit geometries to analyse the influence of the respective geometric and hydraulic parameters and develop a calibration approach in a large-scale heterogeneous karst system. Results show that it is not only possible to derive a consistent flow and transport model for a 150 km2 karst area, but that the combined use of groundwater flow and transport parameters greatly reduces model ambiguity. The approach provides basic information about the conduit network not accessible for direct geometric measurements. The conduit network volume for the main karst spring in the study area could be narrowed down to approximately 100 000 m3.

  5. Resummation ambiguities in the Higgs transverse-momentum spectrum in the Standard Model and beyond

    NASA Astrophysics Data System (ADS)

    Bagnaschi, E.; Harlander, R. V.; Mantler, H.; Vicini, A.; Wiesemann, M.

    2016-01-01

    We study the prediction for the Higgs transverse momentum distribution in gluon fusion and focus on the problem of matching fixed- and all-order perturbative results. The main sources of matching ambiguities on this distribution are investigated by means of a twofold comparison. On the one hand, we present a detailed qualitative and quantitative comparison of two recently introduced algorithms for determining the matching scale [1, 2]. On the other hand, we apply the results of both methods to three widely used approaches for the resummation of logarithmically enhanced contributions at small transverse momenta: the MC@NLO and POWHEG Monte Carlo approaches, and analytic resummation. While the three sets of results are largely compatible in the low- p ⊥ region, they exhibit sizable differences at large p ⊥. We show that these differences can be significantly reduced by suitable modifications of formally subleading terms in the Monte Carlo implementations. We apply our study to the Standard Model Higgs boson and to the neutral Higgs bosons of the Two-Higgs-Doublet Model for representative scenarios of the parameter space, where the top- and bottom-quark diagrams enter the cross section at different strengths.

  6. Sense and sensibility: Swedish midwives' ambiguity to the use of synthetic oxytocin for labour augmentation.

    PubMed

    Ekelin, Maria; Svensson, Judith; Evehammar, Susanne; Kvist, Linda J

    2015-03-01

    The use of intravenous artificial oxytocin for augmentation of labour is very common in midwifery care in Sweden. Studies have shown that oxytocin is often administered to women in labour who have no signs of labour dystocia. It was the aim of this study to examine Swedish midwives' views on and experiences of labour augmentation in the context of normal labour. Individual interviews were carried out with 15 midwives from southern Sweden. The material was analysed using qualitative content analysis, which resulted in one theme: sense and sensibility and four main categories: permissible situations, motivating the decision, intervening in the birth process and iatrogenic awareness. The results showed that midwives expressed ambiguity about augmentation of labour. They were of the opinion that oxytocin was used very often and sometimes unnecessarily. There is awareness that interventions to augment labour can result in undesirable effects on the birth process. Despite this, deeper discussion of this problem was avoided in the interviews. Further research should focus on the process involved when midwives weigh pros and cons when deciding to augment labour. More knowledge is also needed about the barriers for optimal care in labour that are inherent in health-care systems.

  7. Who gives? Multilevel effects of gender and ethnicity on workplace charitable giving.

    PubMed

    Leslie, Lisa M; Snyder, Mark; Glomb, Theresa M

    2013-01-01

    Research on diversity in organizations has largely focused on the implications of gender and ethnic differences for performance, to the exclusion of other outcomes. We propose that gender and ethnic differences also have implications for workplace charitable giving, an important aspect of corporate social responsibility. Drawing from social role theory, we hypothesize and find that gender has consistent effects across levels of analysis; women donate more money to workplace charity than do men, and the percentage of women in a work unit is positively related to workplace charity, at least among men. Alternatively and consistent with social exchange theory, we hypothesize and find that ethnicity has opposing effects across levels of analysis; ethnic minorities donate less money to workplace charity than do Whites, but the percentage of minorities in a work unit is positively related to workplace charity, particularly among minorities. The findings provide a novel perspective on the consequences of gender and ethnic diversity in organizations and highlight synergies between organizational efforts to increase diversity and to build a reputation for corporate social responsibility.

  8. Who gives? Multilevel effects of gender and ethnicity on workplace charitable giving.

    PubMed

    Leslie, Lisa M; Snyder, Mark; Glomb, Theresa M

    2013-01-01

    Research on diversity in organizations has largely focused on the implications of gender and ethnic differences for performance, to the exclusion of other outcomes. We propose that gender and ethnic differences also have implications for workplace charitable giving, an important aspect of corporate social responsibility. Drawing from social role theory, we hypothesize and find that gender has consistent effects across levels of analysis; women donate more money to workplace charity than do men, and the percentage of women in a work unit is positively related to workplace charity, at least among men. Alternatively and consistent with social exchange theory, we hypothesize and find that ethnicity has opposing effects across levels of analysis; ethnic minorities donate less money to workplace charity than do Whites, but the percentage of minorities in a work unit is positively related to workplace charity, particularly among minorities. The findings provide a novel perspective on the consequences of gender and ethnic diversity in organizations and highlight synergies between organizational efforts to increase diversity and to build a reputation for corporate social responsibility. PMID:22985116

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

    PubMed

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

    2007-02-01

    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.

  10. Improvement of PPP-inferred tropospheric estimates by integer ambiguity resolution

    NASA Astrophysics Data System (ADS)

    Shi, J.; Gao, Y.

    2012-11-01

    Integer ambiguity resolution in Precise Point Positioning (PPP) can improve positioning accuracy and reduce convergence time. The decoupled clock model proposed by Collins (2008) has been used to facilitate integer ambiguity resolution in PPP, and research has been conducted to assess the model's potential to improve positioning accuracy and reduce positioning convergence time. In particular, the biggest benefits have been identified for the positioning solutions within short observation periods such as one hour. However, there is little work reported about the model's potential to improve the estimation of the tropospheric parameter within short observation periods. This paper investigates the effect of PPP ambiguity resolution on the accuracy of the tropospheric estimates within one hour. The tropospheric estimates with float and fixed ambiguities within one hour are compared to two external references. The first reference is the International GNSS Service (IGS) final troposphere product based on the PPP technique. The second reference is the Constellation Observing System for Meteorology Ionosphere and Climate (COSMIC) radio occultation (RO) event based on the atmospheric profiles along the signal travel path. A comparison among ten co-located ground-based GPS and space-based RO troposphere zenith path delays shows that the mean bias of the troposphere estimates with float ambiguities can be significantly reduced from 30.1 to 17.0 mm when compared to the IGS troposphere product and from 36.3 to 19.7 mm when compared to the COSMIC RO. The root mean square (RMS) accuracy improvement of the tropospheric parameters by the ambiguity resolution is 33.3% when compared to the IGS products and 44.3% when compared to the COSMIC RO. All these improvements are achieved within one hour, which indicates the promising prospect of adopting PPP integer ambiguity resolution for time-critical applications such as typhoon prediction.

  11. SEPARABLE RESPONSES TO ERROR, AMBIGUITY, AND REACTION TIME IN CINGULO-OPERCULAR TASK CONTROL REGIONS

    PubMed Central

    Neta, Maital; Schlaggar, Bradley L.; Petersen, Steven E.

    2014-01-01

    The dorsal anterior cingulate (dACC), along with the closely affiliated anterior insula/frontal operculum have been demonstrated to show three types of task control signals across a wide variety of tasks. One of these signals, a transient signal that is thought to represent performance feedback, shows greater activity to error than correct trials. Other work has found similar effects for uncertainty/ambiguity or conflict, though some argue that dACC activity is, instead, modulated primarily by other processes more reflected in reaction time. Here, we demonstrate that, rather than a single explanation, multiple information processing operations are crucial to characterizing the function of these brain regions, by comparing operations within a single paradigm. Participants performed two tasks in an fMRI experimental session: (1) deciding whether or not visually presented word pairs rhyme, and (2) rating auditorily presented single words as abstract or concrete. A pilot was used to identify ambiguous stimuli for both tasks (e.g., word pair: BASS/GRACE; single word: CHANGE). We found greater cingulo-opercular activity for errors and ambiguous trials than clear/correct trials, with a robust effect of reaction time. The effects of error and ambiguity remained when reaction time was regressed out, although the differences decreased. Further stepwise regression of response consensus (agreement across participants for each stimulus; a proxy for ambiguity) decreased differences between ambiguous and clear trials, but left error-related differences almost completely intact. These observations suggest that trial-wise responses in cinguloopercular regions monitor multiple performance indices, including accuracy, ambiguity, and reaction time. PMID:24887509

  12. Opposite influence of perceptual memory on initial and prolonged perception of sensory ambiguity.

    PubMed

    de Jong, Maartje Cathelijne; Knapen, Tomas; van Ee, Raymond

    2012-01-01

    Observers continually make unconscious inferences about the state of the world based on ambiguous sensory information. This process of perceptual decision-making may be optimized by learning from experience. We investigated the influence of previous perceptual experience on the interpretation of ambiguous visual information. Observers were pre-exposed to a perceptually stabilized sequence of an ambiguous structure-from-motion stimulus by means of intermittent presentation. At the subsequent re-appearance of the same ambiguous stimulus perception was initially biased toward the previously stabilized perceptual interpretation. However, prolonged viewing revealed a bias toward the alternative perceptual interpretation. The prevalence of the alternative percept during ongoing viewing was largely due to increased durations of this percept, as there was no reliable decrease in the durations of the pre-exposed percept. Moreover, the duration of the alternative percept was modulated by the specific characteristics of the pre-exposure, whereas the durations of the pre-exposed percept were not. The increase in duration of the alternative percept was larger when the pre-exposure had lasted longer and was larger after ambiguous pre-exposure than after unambiguous pre-exposure. Using a binocular rivalry stimulus we found analogous perceptual biases, while pre-exposure did not affect eye-bias. We conclude that previously perceived interpretations dominate at the onset of ambiguous sensory information, whereas alternative interpretations dominate prolonged viewing. Thus, at first instance ambiguous information seems to be judged using familiar percepts, while re-evaluation later on allows for alternative interpretations.

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

    PubMed

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

    2007-02-01

    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. PMID:17228119

  14. How Do Family Caregivers of Older People Give Up Caregiving?

    PubMed Central

    Mortazavi, Hamed; Peyrovi, Hamid; Joolaee, Soodabeh

    2015-01-01

    Background Population aging has social, economic and political consequences. Most family caregivers prefer to care for their family member older person with chronic disease at home. Despite traditional culture within Iranian families, in some cases, hospitalization of the elderly in nursing home is inevitable, and this affects the old person and his/her family. The aim of this study was to explain how Iranian family cargivers give up caring their older person with chronic condition at home. Methods A grounded theory approach was used to conduct the study. The study setting included four nursing homes under the auspices of Iran Welfare Organization. Fourteen participants were recruited through purposive sampling. Data were collected from December 2010 to March 2011 by Semi-structured interviews lasting about 17 to 95 minutes (average 52 minutes). Constant comparative analysis was used to analyze the data. Results Three main categories appeared at the end of the analysis: “going out of the road of usual life”, “challenge of meeting older person, family and caregivers care needs”, and “the appearance of inconstancy in the family”. They explained exclusively how family caregivers of old people give up caregiving. Conclusion Health care providers are recommended to become familiar with challenges of family caregivers in taking care of older person with chronic disease at home, and then organize their supportive and consulting actions according to family situations in order to improve the life quality of older person and family caregivers. PMID:26171407

  15. Johnny Depp, Reconsidered: How Category-Relative Processing Fluency Determines the Appeal of Gender Ambiguity

    PubMed Central

    Owen, Helen E.; Halberstadt, Jamin; Carr, Evan W.; Winkielman, Piotr

    2016-01-01

    Individuals that combine features of both genders–gender blends–are sometimes appealing and sometimes not. Heretofore, this difference was explained entirely in terms of sexual selection. In contrast, we propose that part of individuals’ preference for gender blends is due to the cognitive effort required to classify them, and that such effort depends on the context in which a blend is judged. In two studies, participants judged the attractiveness of male-female morphs. Participants did so after classifying each face in terms of its gender, which was selectively more effortful for gender blends, or classifying faces on a gender-irrelevant dimension, which was equally effortful for gender blends. In both studies, gender blends were disliked when, and only when, the faces were first classified by gender, despite an overall preference for feminine features in all conditions. Critically, the preferences were mediated by the effort of stimulus classification. The results suggest that the variation in attractiveness of gender-ambiguous faces may derive from context-dependent requirements to determine gender membership. More generally, the results show that the difficulty of resolving social category membership–not just attitudes toward a social category–feed into perceivers’ overall evaluations toward category members. PMID:26845341

  16. Johnny Depp, Reconsidered: How Category-Relative Processing Fluency Determines the Appeal of Gender Ambiguity.

    PubMed

    Owen, Helen E; Halberstadt, Jamin; Carr, Evan W; Winkielman, Piotr

    2016-01-01

    Individuals that combine features of both genders-gender blends-are sometimes appealing and sometimes not. Heretofore, this difference was explained entirely in terms of sexual selection. In contrast, we propose that part of individuals' preference for gender blends is due to the cognitive effort required to classify them, and that such effort depends on the context in which a blend is judged. In two studies, participants judged the attractiveness of male-female morphs. Participants did so after classifying each face in terms of its gender, which was selectively more effortful for gender blends, or classifying faces on a gender-irrelevant dimension, which was equally effortful for gender blends. In both studies, gender blends were disliked when, and only when, the faces were first classified by gender, despite an overall preference for feminine features in all conditions. Critically, the preferences were mediated by the effort of stimulus classification. The results suggest that the variation in attractiveness of gender-ambiguous faces may derive from context-dependent requirements to determine gender membership. More generally, the results show that the difficulty of resolving social category membership-not just attitudes toward a social category-feed into perceivers' overall evaluations toward category members. PMID:26845341

  17. Johnny Depp, Reconsidered: How Category-Relative Processing Fluency Determines the Appeal of Gender Ambiguity.

    PubMed

    Owen, Helen E; Halberstadt, Jamin; Carr, Evan W; Winkielman, Piotr

    2016-01-01

    Individuals that combine features of both genders-gender blends-are sometimes appealing and sometimes not. Heretofore, this difference was explained entirely in terms of sexual selection. In contrast, we propose that part of individuals' preference for gender blends is due to the cognitive effort required to classify them, and that such effort depends on the context in which a blend is judged. In two studies, participants judged the attractiveness of male-female morphs. Participants did so after classifying each face in terms of its gender, which was selectively more effortful for gender blends, or classifying faces on a gender-irrelevant dimension, which was equally effortful for gender blends. In both studies, gender blends were disliked when, and only when, the faces were first classified by gender, despite an overall preference for feminine features in all conditions. Critically, the preferences were mediated by the effort of stimulus classification. The results suggest that the variation in attractiveness of gender-ambiguous faces may derive from context-dependent requirements to determine gender membership. More generally, the results show that the difficulty of resolving social category membership-not just attitudes toward a social category-feed into perceivers' overall evaluations toward category members.

  18. Ambiguity in measuring matrix diffusion with single-well injection/recovery tracer tests

    USGS Publications Warehouse

    Lessoff, S.C.; Konikow, L.F.

    1997-01-01

    Single-well injection/recovery tracer tests are considered for use in characterizing and quantifying matrix diffusion in dual-porosity aquifers. Numerical modeling indicates that neither regional drift in homogeneous aquifers, nor heterogeneity in aquifers having no regional drift, nor hydrodynamic dispersion significantly affects these tests. However, when drift is coupled simultaneously with heterogeneity, they can have significant confounding effects on tracer return. This synergistic effect of drift and heterogeneity may help explain irreversible flow and inconsistent results sometimes encountered in previous single-well injection/recovery tracer tests. Numerical results indicate that in a hypothetical single-well injection/recovery tracer test designed to demonstrate and measure dual-porosity characteristics in a fractured dolomite, the simultaneous effects of drift and heterogeneity sometimes yields responses similar to those anticipated in a homogeneous dual-porosity formation. In these cases, tracer recovery could provide a false indication of the occurrence of matrix diffusion. Shortening the shut-in period between injection and recovery periods may make the test less sensitive to drift. Using multiple tracers having different diffusion characteristics, multiple tests having different pumping schedules, and testing the formation at more than one location would decrease the ambiguity in the interpretation of test data.

  19. GLONASS fractional-cycle bias estimation across inhomogeneous receivers for PPP ambiguity resolution

    NASA Astrophysics Data System (ADS)

    Geng, Jianghui; Bock, Yehuda

    2016-04-01

    The key issue to enable precise point positioning with ambiguity resolution (PPP-AR) is to estimate fractional-cycle biases (FCBs), which mainly relate to receiver and satellite hardware biases, over a network of reference stations. While this has been well achieved for GPS, FCB estimation for GLONASS is difficult because (1) satellites do not share the same frequencies as a result of Frequency Division Multiple Access (FDMA) signals; (2) and even worse, pseudorange hardware biases of receivers vary in an irregular manner with manufacturers, antennas, domes, firmware, etc., which especially complicates GLONASS PPP-AR over inhomogeneous receivers. We propose a general approach where external ionosphere products are introduced into GLONASS PPP to estimate precise FCBs that are less impaired by pseudorange hardware biases of diverse receivers to enable PPP-AR. One month of GLONASS data at about 550 European stations were processed. From an exemplary network of 51 inhomogeneous receivers, including four receiver types with various antennas and spanning about 800 km in both longitudinal and latitudinal directions, we found that 92.4 % of all fractional parts of GLONASS wide-lane ambiguities agree well within ± 0.15 cycles with a standard deviation of 0.09 cycles if global ionosphere maps (GIMs) are introduced, compared to only 51.7 % within ± 0.15 cycles and a larger standard deviation of 0.22 cycles otherwise. Hourly static GLONASS PPP-AR at 40 test stations can reach position estimates of about 1 and 2 cm in RMS from ground truth for the horizontal and vertical components, respectively, which is comparable to hourly GPS PPP-AR. Integrated GLONASS and GPS PPP-AR can further achieve an RMS of about 0.5 cm in horizontal and 1-2 cm in vertical components. We stress that the performance of GLONASS PPP-AR across inhomogeneous receivers depends on the accuracy of ionosphere products. GIMs have a modest accuracy of only 2-8 TECU (Total Electron Content Unit) in vertical

  20. Measuring the subjective value of risky and ambiguous options using experimental economics and functional MRI methods.

    PubMed

    Levy, Ifat; Rosenberg Belmaker, Lior; Manson, Kirk; Tymula, Agnieszka; Glimcher, Paul W

    2012-09-19

    Most of the choices we make have uncertain consequences. In some cases the probabilities for different possible outcomes are precisely known, a condition termed "risky". In other cases when probabilities cannot be estimated, this is a condition described as "ambiguous". While most people are averse to both risk and ambiguity(1,2), the degree of those aversions vary substantially across individuals, such that the subjective value of the same risky or ambiguous option can be very different for different individuals. We combine functional MRI (fMRI) with an experimental economics-based method(3 )to assess the neural representation of the subjective values of risky and ambiguous options(4). This technique can be now used to study these neural representations in different populations, such as different age groups and different patient populations. In our experiment, subjects make consequential choices between two alternatives while their neural activation is tracked using fMRI. On each trial subjects choose between lotteries that vary in their monetary amount and in either the probability of winning that amount or the ambiguity level associated with winning. Our parametric design allows us to use each individual's choice behavior to estimate their attitudes towards risk and ambiguity, and thus to estimate the subjective values that each option held for them. Another important feature of the design is that the outcome of the chosen lottery is not revealed during the experiment, so that no learning can take place, and thus the ambiguous options remain ambiguous and risk attitudes are stable. Instead, at the end of the scanning session one or few trials are randomly selected and played for real money. Since subjects do not know beforehand which trials will be selected, they must treat each and every trial as if it and it alone was the one trial on which they will be paid. This design ensures that we can estimate the true subjective value of each option to each subject. We