Sample records for give ambiguous results

  1. Confidence Intervals: Giving Meaning to your results

    E-print Network

    Gilleland, Eric

    Confidence Intervals: Giving Meaning to your results Eric Gilleland EricG@ucar.edu · What does RMSE Testing and Confidence Intervals · Hypothesis testing ­ Given a null hypothesis (e.g., "Model forecast a single null hypothesis. · Confidence intervals ­ Related to hypothesis tests, but more useful. ­ How

  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. 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

  5. Ambiguous Genitalia

    MedlinePLUS

    ... being, future sexual function and fertility, and stable gender identity. ambiguous genitalia definitions sex chromosomes: the X and ... the sex in which a child is raised. gender identity: how people think of themselvesas male or ...

  6. Ambiguous Cube

    NSDL National Science Digital Library

    Don Rathjen

    2009-01-01

    In this activity, learners construct a three-dimensional ambiguous cube to explore visual illusions and how our brains interpret or misinterpret information. Learners will be surprised to see what the cube looks like when they hinder their depth perception by viewing it with only one eye.

  7. 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

  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 4.3213.88). 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. Risk, ambiguity, and insurance

    Microsoft Academic Search

    Robin M. Hogarth; Howard Kunreuther

    1989-01-01

    In a series of experiments, economically sophisticated subjects, including professional actuaries, priced insurance both as consumers and as firms under conditions of ambiguity. Findings support implications of the Einhorn-Hogarth ambiguity model: (1) For low probability-of-loss events, prices of both consumers and firms indicated aversion to ambiguity; (2) As probabilities of losses increased, aversion to ambiguity decreased, with consumers exhibiting ambiguity

  10. Ambiguities analysis in SAR tomography

    NASA Astrophysics Data System (ADS)

    Wang, Ziwei; Zhang, Hong; Wang, Chao; Tang, Yixian; Zhang, Bo

    2014-10-01

    Synthetic aperture radar tomography (TomoSAR) is typically used to retrieve elevation, deformation, and other key information by separating scatters of the same slant range in multiple baseline SAR images. In this paper, we investigate two kinds of ambiguities for TomoSAR. Rank-1 ambiguity, as the first one we concerned, is due to the baseline distribution of the SAR image dataset which makes the steering matrix out of full rank. It will result in false alarms appearing in a permanent distance. However, an example using the TomoSAR imaging parameters shows this ambiguity makes no sense in most cases. The second ambiguity refers to the coherence of scatters contained in one pixel. In simulation experiment, the coherence will enhance the side lobes of the spectrum, even make the real peaks fused.

  11. 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.

  12. 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: 58, 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

  13. 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

  14. Two Cheers for Ambiguity.

    ERIC Educational Resources Information Center

    Holden, William

    Ambiguity can be enjoyed in statements without context, in unclear comparisons, in words often confused, and in casual disorders. In spite of the grammarians' efforts to "disambiguate," it is doubtful that any willful act or combination of acts can eliminate ambiguity, since language is a system of symbols which can stand for one thing or another.

  15. Nonperturbative Ambiguities and the Reality of Resurgent Transseries

    NASA Astrophysics Data System (ADS)

    Aniceto, Ins; Schiappa, Ricardo

    2015-04-01

    In a wide range of quantum theoretical settingsfrom quantum mechanics to quantum field theory, from gauge theory to string theorysingularities in the complex Borel plane, usually associated to instantons or renormalons, render perturbation theory ill-defined as they give rise to nonperturbative ambiguities. These ambiguities are associated to choices of an integration contour in the resummation of perturbation theory, along (singular) Stokes directions in the complex Borel plane (rendering perturbative expansions non-Borel summable along any Stokes line). More recently, it has been shown that the proper framework to address these issues is that of resurgent analysis and transseries. In this context, the cancelation of all nonperturbative ambiguities is shown to be a consequence of choosing the transseries median resummation as the appropriate family of unambiguous real solutions along the coupling-constant real axis. While the median resummation is easily implemented for one-parameter transseries, once one considers more general multi-parameter transseries the procedure becomes highly dependent upon properly understanding Stokes transitions in the complex Borel plane. In particular, all Stokes coefficients must now be known in order to explicitly implement multi-parameter median resummations. In the cases where quantum-theoretical physical observables are described by resurgent functions and transseries, the methods described herein show how one may cancel nonperturbative ambiguities, and define these observables nonperturbatively starting out from perturbation theory. Along the way, structural results concerning resurgent transseries are also obtained.

  16. VALUING AMBIGUITY: THE CASE OF GENETICALLY ENGINEERED GROWTH ENHANCERS

    Microsoft Academic Search

    Brian L. Buhr; Dermot J. Hayes; Jason F. Shogren; James B. Kliebenstein

    1993-01-01

    A split-valuation method is developed and implemented to elicit the willingness to pay to consume- or avoid consuming- a product of ambiguous quality. The split-valuation method uses experimental auction markets to separate and value the positive and negative attributes of the ambiguous good. The results show that the method can be used to successfully value a good ambiguous quality. Our

  17. The ambiguity of contents and results in the Norwegian internal control of safety, health and environment reform

    Microsoft Academic Search

    Jan Hovden

    1998-01-01

    The results of introducing a mandatory public reform in Norway with regard to the requirements on enterprises' management of safety, health and environment (SHE) systems are reviewed and discussed. The reform, named internal control (IC), implies a delegation of the direct control of SHE conditions to the enterprises, and introduces system auditing as the main tool for the regulatory bodies.

  18. Six Common Causes of Ambiguity.

    ERIC Educational Resources Information Center

    Messer, Donald K.

    1980-01-01

    Indicates that ambiguity, one of the major faults of technical prose, occurs in at least six ways: ambiguity by implication, ambiguous word order, ambiguous words, dangling participles, improper or missing punctuation, and faulty pronoun reference. Suggests cures for each and provides examples for students to discuss and correct. (TJ)

  19. Ambiguities in Pauli-Villars regularization

    NASA Astrophysics Data System (ADS)

    Kleiss, R. H. P.; Janssen, T.

    2015-02-01

    We investigate regularization of scalar one-loop integrals in the Pauli-Villars subtraction scheme. The results depend on the number of subtractions, in particular the finite terms that survive after the divergences have been absorbed by renormalization. Therefore the process of Pauli-Villars regularization is ambiguous. We discuss how these ambiguities may be resolved by applying an asymptotically large number of subtractions, which results in a regularization that is automatically valid in any number of dimensions.

  20. 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.

  1. 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

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

    PubMed

    Osmont, Anas; Cassotti, Mathieu; Agogu, Marine; Houd, Olivier; Moutier, Sylvain

    2015-04-01

    Decision-makers present a systematic tendency to avoid ambiguous options for which the level of risk is unknown. This ambiguity aversion is one of the most striking decision-making biases. Given that human choices strongly depend on the options' presentation, the purpose of the present study was to examine whether ambiguity aversion influences the framing effect during decision making. We designed a new financial decision-making task involving the manipulation of both frame and uncertainty levels. Thirty-seven participants had to choose between a sure option and a gamble depicting either clear or ambiguous probabilities. The results revealed a clear preference for the sure option in the ambiguity condition regardless of frame. However, participants presented a framing effect in both the risk and ambiguity conditions. Indeed, the framing effect was bidirectional in the risk condition and unidirectional in the ambiguity condition given that it did not involve preference reversal but only a more extreme choice tendency. PMID:25030206

  3. Ambiguous Probabilistic Programs

    E-print Network

    2013-09-11

    to minimize the probability of failure, ruin, or occurrence of certain undesirable events, ..... degenerate case where b = 1, it is easy to see the ambiguity set has only one element, i.e., the ...... approach to stochastic programming of heating oil.

  4. 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

  5. Boundary Ambiguity in Stepfamilies

    Microsoft Academic Search

    Susan D. Stewart

    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 first-married, remarried, and cohabiting couples with

  6. 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

  7. 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

  8. Reduction of aliasing ambiguities through phase relations

    NASA Astrophysics Data System (ADS)

    Sanderson, Richard B.; Tsui, James B. Y.; Freese, Nancy A.

    1992-10-01

    A method for digital determination of a single frequency from a sine wave sampled at less than the Nyquist rate is discussed. The method makes use of phase shift information to eliminate the aliasing ambiguity. Multiple sampled data are required to eliminate ambiguity completely. Computer modeling using simulated data corrupted by uncorrelated Gaussian noise was used to verify the approach. The results demonstrate that the frequency of an input sine wave can be correctly identified. This approach can be applied to electronic warfare (EW) receivers to increase their input bandwidth.

  9. Learning, Teaching and Ambiguity in Virtual Worlds

    NASA Astrophysics Data System (ADS)

    Carr, Diane; Oliver, Martin; Burn, Andrew

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

  10. The Ambiguity of the Child's "Voice" in Social Research

    ERIC Educational Resources Information Center

    Komulainen, Sirkka

    2007-01-01

    This article addresses the ambiguity of the child's "voice" in social research. Drawing on a recent research project on young children's communication difficulties, the author argues that the currently popular discourse on "listening to children" is beset with practical and ethical ambiguities that result from the "socialness" of human

  11. The Impact of Role Conflict and Ambiguity on Academic Deans.

    ERIC Educational Resources Information Center

    Wolverton, Mimi; Wolverton, Marvin L.; Gmelch, Walter H.

    1999-01-01

    College deans serve as both extensions of the presidency (through the provost) and extensions of the faculty. This puts them in situations confounded by ambiguity and role conflict. A discussion of the impact of this role conflict and ambiguity on deans, particularly the resulting high turnover and low productivity, suggests policy implications

  12. Gribov ambiguity and degenerate systems

    NASA Astrophysics Data System (ADS)

    Canfora, Fabrizio; de Micheli, Fiorenza; Salgado-Rebolledo, Patricio; Zanelli, Jorge

    2014-08-01

    The relation between Gribov ambiguity and degeneracies in the symplectic structure of physical systems is analyzed. It is shown that, in finite-dimensional systems, the presence of Gribov ambiguities in regular constrained systems (those where the constraints are functionally independent) always leads to a degenerate symplectic structure upon Dirac reduction. The implications for the Gribov-Zwanziger approach to QCD are discussed.

  13. Which aluminium fractionation method will give true inorganic monomeric Al results in fresh waters (not including colloidal Al)?

    PubMed

    Andrn, Cecilia M; Rydin, Emil

    2009-09-01

    Aluminium solubility and toxicity increase with acidification. There is no standardized analytical method for the determination of inorganic monomeric Al (Al(im)), which is the form that causes toxicity to fish. Separation by cation exchange is commonly combined with other analytical methods, such as complexation with pyrochatechol violet (PCV) or 8-hydroxyquinoline (HQ) and total quantification using graphite furnace or inductively-coupled plasma emission. Data from 14 laboratories were obtained for a dilution series of Al(im) samples; the results of the Al(im) analysis were statistically evaluated. The Al(im) levels were altered through pH, which was controlled by the addition of calcium hydroxide. Confounding parameters such as total organic carbon (TOC) or fluoride (F) were controlled. The total determination and HQ methods yielded significantly higher Al(im) concentrations than the PCV method. Pretreatment by passage through a 0.45 microm filter and pH-adjustment of the ion exchange column had no apparent effect on the Al(im) yield. However, ultra filtration (<10 kDa) caused a significant reduction in the Al(im) concentration using the HQ method. The ultra filtrated Al(im) fraction was similar to the PCV results in the interlaboratory comparison. Retention of colloidal bound Al in the cation exchange column may result in overestimation of Al(im) when the total and HQ methods are used. Estimated Al(im) concentrations derived from two equilibrium models were similar to PCV-derived Al(im) concentrations, as well as the HQ method using ultra filtrated water. The fact that the PCV method does not detect colloidal Al, neither before nor after ion exchange, makes this a preferred technique for Al(im) analysis. Because of the variability in the reported Al(im) concentrations that can arise when different analytical procedures are used, the adoption of a single, reliable technique will facilitate inter-study comparisons and provide consistency in the detection of trends in environmental monitoring programs. PMID:19724834

  14. Israel's nuclear ambiguity

    SciTech Connect

    Cohen, A.; Frankel, B.

    1987-03-01

    On October 5, 1986, the London Sunday Times published details of secret Israeli nuclear weapons manufacturing, indicating that over the past 20 years Israel may have accumulated a nuclear arsenal of 100 to 200 weapons. While not entirely new, these recent revelations, in contrast to past information, are attributed to an identifiable source: Mordechai Vanunu, a former technician in Israel's Dimona nuclear facility. The prompt Israeli action that brought Vanunu to Israel to stand trial indicates how seriously the Israeli government has treated his story. The revelations bring into sharp focus the peculiar features of Israel's nuclear posture and the difficulty inherent in any serious discussion of the subject - notably the secrecy that has surrounded the program since its inception. To Israelis, no defense-related topic more sensitive. Although there is some evidence of internal debate at key junctures in the history of the Israeli nuclear project, there has never been any serious public questioning of the program, or its direction, from its inception three decades ago to the present, a period spanning the tenures of seven prime ministers. In view of the above revelations, the authors review Israel's nuclear weapons policy, deliberately ambiguous, and discuss possible alternatives in the context of possible nonproliferation efforts by the superpowers. 14 references, 2 figures.

  15. Ambiguities in helical reconstruction

    PubMed Central

    Egelman, Edward H

    2014-01-01

    Helical polymers are found throughout biology and account for a substantial fraction of the protein in a cell. These filaments are very attractive for three-dimensional reconstruction from electron micrographs due to the fact that projections of these filaments show many different views of identical subunits in identical environments. However, ambiguities exist in defining the symmetry of a helical filament when one has limited resolution, and mistakes can be made. Until one reaches a near-atomic level of resolution, there are not necessarily reality-checks that can distinguish between correct and incorrect solutions. A recent paper in eLife (Xu et al., 2014) almost certainly imposed an incorrect helical symmetry and this can be seen using filament images posted by Xu et al. A comparison between the atomic model proposed and the published three-dimensional reconstruction should have suggested that an incorrect solution was found. DOI: http://dx.doi.org/10.7554/eLife.04969.001 PMID:25486515

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

    PubMed Central

    Lopez-Paniagua, Dan; Seger, Carol A.

    2013-01-01

    Data from previous neuroimaging studies exploring neural activity associated with uncertainty suggest varying levels of activation associated with changing degrees of uncertainty in neural regions that mediate choice behavior. The present study used a novel task that parametrically controlled the amount of information hidden from the subject; levels of uncertainty ranged from full ambiguity (no information about probability of winning) through multiple levels of partial ambiguity, to a condition of risk only (zero ambiguity with full knowledge of the probability of winning). A parametric analysis compared a linear model in which weighting increased as a function of level of ambiguity, and an inverted-U quadratic models in which partial ambiguity conditions were weighted most heavily. Overall we found that risk and all levels of ambiguity recruited a common frontoparietalstriatal network including regions within the dorsolateral prefrontal cortex, intraparietal sulcus, and dorsal striatum. Activation was greatest across these regions and additional anterior and superior prefrontal regions for the quadratic function which most heavily weighs trials with partial ambiguity. These results suggest that the neural regions involved in decision processes do not merely track the absolute degree ambiguity or type of uncertainty (risk vs. ambiguity). Instead, recruitment of prefrontal regions may result from greater degree of difficulty in conditions of partial ambiguity: when information regarding reward probabilities important for decision making is hidden or not easily obtained the subject must engage in a search for tractable information. Additionally, this study identified regions of activity related to the valuation of potential gains associated with stimuli or options (including the orbitofrontal and medial prefrontal cortices and dorsal striatum) and related to winning (including orbitofrontal cortex and ventral striatum). PMID:24367286

  17. To mind the mind: An event-related potential study of word class and semantic ambiguity

    PubMed Central

    Lee, Chia-lin; Federmeier, Kara D.

    2009-01-01

    The goal of this study was to jointly examine the effects of word class, word class ambiguity, and semantic ambiguity on the brain response to words in syntactically specified contexts. Four types of words were used: (1) word class ambiguous words with a high degree of semantic ambiguity (e.g., duck); (2) word class ambiguous words with little or no semantic ambiguity (e.g., vote); (3) word class unambiguous nouns (e.g., sofa); and (4) word class unambiguous verbs (e.g., eat). These words were embedded in minimal phrases that explicitly specified their word class: the for nouns (and ambiguous words used as nouns) and to for verbs (and ambiguous words used as verbs). Our results replicate the basic word class effects found in prior work (Federmeier, K.D., Segal, J.B., Lombrozo, T., Kutas, M., 2000. Brain responses to nouns, verbs and class ambiguous words in context. Brain, 123 (12), 25522566), including an enhanced N400 (250450ms) to nouns compared with verbs and an enhanced frontal positivity (300700 ms) to unambiguous verbs in relation to unambiguous nouns. A sustained frontal negativity (250900 ms) that was previously linked to word class ambiguity also appeared in this study but was specific to word class ambiguous items that also had a high level of semantic ambiguity; word class ambiguous items without semantic ambiguity, in contrast, were more positive than class unambiguous words in the early part of this time window (250500 ms). Thus, this frontal negative effect seems to be driven by the need to resolve the semantic ambiguity that is sometimes associated with different grammatical uses of a word class ambiguous homograph rather than by the class ambiguity per se. PMID:16516169

  18. Regularization ambiguities in loop quantum gravity

    SciTech Connect

    Perez, Alejandro [Centre de Physique Theorique, Campus de Luminy, 13288 Marseille (France)

    2006-02-15

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

  19. Alcohol reduces aversion to ambiguity

    PubMed Central

    Tyszka, Tadeusz; Macko, Anna; Sta?czak, Maciej

    2015-01-01

    Several years ago, Cohen et al. (1958) demonstrated that under the influence of alcohol drivers became more risk prone, although their risk perception remained unchanged. Research shows that ambiguity aversion is to some extent positively correlated with risk aversion, though not very highly (Camerer and Weber, 1992). The question addressed by the present research is whether alcohol reduces ambiguity aversion. Our research was conducted in a natural setting (a restaurant bar), where customers with differing levels of alcohol intoxication were offered a choice between a risky and an ambiguous lottery. We found that alcohol reduced ambiguity aversion and that the effect occurred in men but not women. We interpret these findings in terms of the risk-as-value hypothesis, according to which, people in Western culture tend to value risk, and suggest that alcohol consumption triggers adherence to socially and culturally valued patterns of conduct different for men and women. PMID:25642202

  20. Probabilistic Constraints and Syntactic Ambiguity Resolution.

    ERIC Educational Resources Information Center

    MacDonald, Maryellen C.

    1994-01-01

    Studied "pre-ambiguity" plausibility information, information about verb argument structure frequencies, and "post-ambiguity" constraints in undergraduates. All three types of constraints were helpful in the resolution of ambiguities. Ambiguity resolution becomes more difficult as the competitor interpretations becomes stronger. Study items are

  1. Resolution Of Phase Ambiguities In QPSK

    NASA Technical Reports Server (NTRS)

    Nguyen, Tien M.

    1992-01-01

    Report discusses several techniques for resolution of phase ambiguities in detection and decoding of radio signals modulated by coherent quadrature phase-shift keying (QPSK) and offset QPSK (OQPSK). Eight ambiguities: four associated with phase of carrier signal in absence of ambiguity in direction of rotation of carrier phase, and another four associated with carrier phase in presence of phase-rotation ambiguity.

  2. Resolving piston ambiguities when phasing a segmented mirror

    Microsoft Academic Search

    Mats G. Lofdahl; Henrik Eriksson

    2000-01-01

    Wavefront sensing in monochromatic light is insensitive to segment piston errors that are a whole number of waves. If the wavefront sensing is performed in several wavelengths, this ambiguity can be resolved. We give an algorithm for finding the correct phase, given multiple measurements in different wavelengths. Using this algorithm, the capture range of a wavefront sensor can be extended

  3. Resolving Piston Ambiguities when Phasing a Segmented Mirror

    Microsoft Academic Search

    Henrik Erikssonb

    Wavefront sensing in monochromatic light is insensitive to segment piston errors that are a whole number of waves. If the wavefront sensing is performed in several wavelengths, this ambiguity can be resolved. We give an algorithm for finding the correct phase, given multiple measurements in different wavelengths. Using this algorithm, the capture range of a wavefront sensor can be extended

  4. Elliptic and almost hyperbolic symmetries for the Woodward ambiguity function

    Microsoft Academic Search

    Charles Darmet; Jean-paul Gauthier; Franois Gourd

    1991-01-01

    The authors deal with the radar ambiguity functions and their symmetries. It is well known that Hermite functions give rise to elliptic symmetries. Hermite functions are eigenvectors of the harmonic-oscillator Schrodinger operator. It is shown that the situation is essentially the same for hyperbolic symmetries: the signals are eigenvectors of the Schrodinger operator associated to the hyperbolic oscillator. Since this

  5. Verbal Creativity and Ambiguity Resolution in the Cerebral Hemispheres

    E-print Network

    Gibson, Linzi Marie

    2013-12-31

    This study examined hemispheric differences in ambiguity resolution in subjects who vary on measures of creativity. Subjects were classified as either low, moderate, or high creative based on the results of convergent and ...

  6. Measuring Ambiguity in HLA Typing Methods

    PubMed Central

    Madbouly, Abeer; Freeman, John; Maiers, Martin

    2012-01-01

    In hematopoietic stem cell transplantation, donor selection is based primarily on matching donor and patient HLA genes. These genes are highly polymorphic and their typing can result in exact allele assignment at each gene (the resolution at which patients and donors are matched), but it can also result in a set of ambiguous assignments, depending on the typing methodology used. To facilitate rapid identification of matched donors, registries employ statistical algorithms to infer HLA alleles from ambiguous genotypes. Linkage disequilibrium information encapsulated in haplotype frequencies is used to facilitate prediction of the most likely haplotype assignment. An HLA typing with less ambiguity produces fewer high-probability haplotypes and a more reliable prediction. We estimated ambiguity for several HLA typing methods across four continental populations using an information theory-based measure, Shannon's entropy. We used allele and haplotype frequencies to calculate entropy for different sets of 1,000 subjects with simulated HLA typing. Using allele frequencies we calculated an average entropy in Caucasians of 1.65 for serology, 1.06 for allele family level, 0.49 for a 2002-era SSO kit, and 0.076 for single-pass SBT. When using haplotype frequencies in entropy calculations, we found average entropies of 0.72 for serology, 0.73 for allele family level, 0.05 for SSO, and 0.002 for single-pass SBT. Application of haplotype frequencies further reduces HLA typing ambiguity. We also estimated expected confirmatory typing mismatch rates for simulated subjects. In a hypothetical registry with all donors typed using the same method, the entropy values based on haplotype frequencies correspond to confirmatory typing mismatch rates of 1.31% for SSO versus only 0.08% for SBT. Intermediate-resolution single-pass SBT contains the least ambiguity of the methods we evaluated and therefore the most certainty in allele prediction. The presented measure objectively evaluates HLA typing methods and can help define acceptable HLA typing for donor recruitment. PMID:22952712

  7. 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.

  8. 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.

  9. Performance analysis of multiple PRF technique for ambiguity resolution

    NASA Technical Reports Server (NTRS)

    Chang, C. Y.; Curlander, J. C.

    1992-01-01

    For short wavelength spaceborne synthetic aperture radar (SAR), ambiguity in Doppler centroid estimation occurs when the azimuth squint angle uncertainty is larger than the azimuth antenna beamwidth. Multiple pulse recurrence frequency (PRF) hopping is a technique developed to resolve the ambiguity by operating the radar in different PRF's in the pre-imaging sequence. Performance analysis results of the multiple PRF technique are presented, given the constraints of the attitude bound, the drift rate uncertainty, and the arbitrary numerical values of PRF's. The algorithm performance is derived in terms of the probability of correct ambiguity resolution. Examples, using the Shuttle Imaging Radar-C (SIR-C) and X-SAR parameters, demonstrate that the probability of correct ambiguity resolution obtained by the multiple PRF technique is greater than 95 percent and 80 percent for the SIR-C and X-SAR applications, respectively. The success rate is significantly higher than that achieved by the range cross correlation technique.

  10. 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

  11. 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

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

    PubMed

    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

  13. 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

  14. 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

  15. Identifying Nocuous Ambiguities in Natural Language Requirements

    Microsoft Academic Search

    Francis Chantree; Bashar Nuseibeh; Anne N. De Roeck; Alistair Willis

    2006-01-01

    We present a novel technique that automatically alerts authors of requirements to the presence of potentially dangerous ambiguities. We first establish the notion of nocuous ambiguities, which are those that are likely to lead to misunderstandings. We test our approach on coordination ambiguities, which occur when words such as and or are used. Our starting point is a dataset of

  16. Ambiguity and ESL Students: A Pilot Experiment.

    ERIC Educational Resources Information Center

    Peng, Lim Ho

    1990-01-01

    A pilot experiment examined ambiguity in English-as-a-Second-Language (ESL) learning by graduate and undergraduate students. The findings revealed that most ESL speakers have greatest difficulty in understanding sentences with derived-structure ambiguity. Underlying-structure ambiguity was the next most difficult to understand, followed by lexical

  17. 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

  18. Ambiguity in Flores de papel

    E-print Network

    Ló pez, Daniel

    1978-10-01

    , behavior, and motivations of El Merluza with ambiguity in order to involve the spectator/reader in the proceedings, com pelling him to supply his own interpretation of people and events as he is con fronted with very few facts. Besides fulfilling...? Es ese el secreto que guarda la hielera? . . . . (p. 193) As Eva stands mutely by, he further reduces such puzzling utterances as these to the total absurdity of nonsensical sounds, thereby suppressing any means of com munication: "Uku! Azakamb...

  19. An Improved Approach to Network Ambiguity Validation by Applying Outlier Detection to the Baseline Measurement Errors

    NASA Astrophysics Data System (ADS)

    Li, Xian; Wu, Meiping; Zhang, Kaidong; He, Xiaofeng; Huang, Yangming

    2013-03-01

    As a prerequisite of network differential global positioning system applications, the network ambiguity must be determined. Ambiguity resolution and validation are important aspects of this process. However, validation theory is still under investigation. This paper presents an improved network ambiguity validation method that incorporates additional knowledge measured from the network. This process involves the detection of outliers of the baseline measurement errors. By breaking the spatial correlation, incorrectly fixed ambiguities cause the corresponding baseline measurement errors to appear as outliers, which may be discovered and identified with the proposed outlier detection algorithm and outlier identification algorithm, respectively. These detection and identification procedures are iteratively performed until all of the wrong baseline ambiguities are corrected. Because the validation procedure is unconnected to the initial integer ambiguity estimation process, any available ambiguity resolution method may be used to obtain the initial integers, without algorithm correction. When the network ambiguity combinations do not pass the validation algorithm, the method uses a direct estimation algorithm to obtain the correct ambiguity. By using a direct estimation algorithm rather than a search process, this new method consumes less computational time than conventional methods. This study compares the performance of this new method with those of the conventional F-ratio and W-ratio test validation algorithms by using Monte Carlo simulation techniques. Results from a field experiment conducted on data from the United States continuously operating reference stations (US-CORS) reveal that this validation algorithm accelerates the convergence process of ambiguity determination.

  20. Frontal lobe networks for effective processing of ambiguously expressed emotions in humans.

    PubMed

    Nomura, Michio; Iidaka, Tetsuya; Kakehi, Kazuhiko; Tsukiura, Takashi; Hasegawa, Takehiro; Maeda, Yasuhiro; Matsue, Yoshihiko

    2003-09-11

    This study examines the neural substrates involved in the recognition of ambiguous facial expressions using functional magnetic resonance imaging. Subjects performed two tasks, one in which they judged facial expressions and another in which they identified gender. Subtraction between ambiguous expression and clear expression conditions revealed the activation of anterior cingulate (ACC), medial frontal (MeFG) and bilateral inferior frontal gyrus (IFG). Structural equation modeling showed that the functional connectivity between these areas was greater with the ambiguous expressions than with the clear ones. The activation of the ACC, MeFG, and right IFG was greater with ambiguous expressions than with ambiguous gender. These results suggest that the neural network involving these frontal regions plays a crucial role in the processing of the ambiguously expressed facial emotions. PMID:12902031

  1. Social anxiety and interpretation of ambiguous smiles.

    PubMed

    Gutirrez-Garca, Aida; Calvo, Manuel G

    2014-01-01

    This study investigated whether social anxiety facilitates the discrimination between genuine and ambiguous smiles. Socially anxious (N=20) and nonanxious (N=20) participants categorized as "happy" or "not happy" faces with either (1) a truly happy expression (i.e., happy eyes and a smile), (2) truly nonhappy expressions (e.g., angry eyes and an angry mouth), or (3) blended expressions with a smiling mouth and nonhappy (e.g., angry, sad, etc.) eyes. Results indicated that, relative to nonanxious participants, those high in social anxiety were more likely to judge as "not happy" any blended expression with nonhappy eyes, and they were faster in judging as "not happy" the blended expressions with angry, fearful, or disgusted eyes (but not those with sad, surprised, or neutral eyes). These results suggest, respectively, that social anxiety inhibits a benign interpretation of all the ambiguous expressions with a smile, and speeds up the detection of threatening eyes in such expressions. Importantly, no differences appeared as a function of social anxiety for truly happy or nonhappy faces. This rules out a response-bias explanation, and also reveals that social anxiety does not affect sensitivity in the recognition of prototypical expressions. PMID:23662633

  2. Generalized integer aperture estimation for partial GNSS ambiguity fixing

    NASA Astrophysics Data System (ADS)

    Brack, Andreas; Gnther, Christoph

    2014-05-01

    In satellite navigation, the key to high precision is to make use of the carrier-phase measurements. The periodicity of the carrier-phase, however, leads to integer ambiguities. Often, resolving the full set of ambiguities cannot be accomplished for a given reliability constraint. In that case, it can be useful to resolve a subset of ambiguities. The selection of the subset should be based not only on the stochastic system model but also on the actual measurements from the tracking loops. This paper presents a solution to the problem of joint subset selection and ambiguity resolution. The proposed method can be interpreted as a generalized version of the class of integer aperture estimators. Two specific realizations of this new class of estimators are presented, based on different acceptance tests. Their computation requires only a single tree search, and can be efficiently implemented, e.g., in the framework of the well-known LAMBDA method. Numerical simulations with double difference measurements based on Galileo E1 signals are used to evaluate the performance of the introduced estimation schemes under a given reliability constraint. The results show a clear gain of partial fixing in terms of the probability of correct ambiguity resolution, leading to improved baseline estimates.

  3. Resolving distance ambiguities towards 6.7 GHz methanol masers

    E-print Network

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

    2008-05-17

    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. 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. We measured 21 cm HI absorption spectra using the Very Large Array in C and CnB configurations. A comparison of the maximum velocity of HI absorption with the source velocity and tangent point velocity was used to resolve the kinematic distance ambiguity. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2014-05-01

    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.

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

    SciTech Connect

    Cheoun, Myung-Ki; Miyatsu, Tsuyoshi; Ryu, C. Y. [Department of Physics, Soongsil University, Seoul 156-743 (Korea, Republic of); Deliduman, Cemsinan [Department of Physics, Mimar Sinan Fine Arts University, Bomonti 34380, Istanbul (Turkey); Gngr, Can; Kele?, Vildan [Istanbul Technical University, Faculty of Science and Letters, Physics Engineering Department, Maslak 34469, Istanbul (Turkey); Kajino, Toshitaka [National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan and Department of Astronomy, Graduate School of Science, University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo 113-0033 (Japan); Mathews, Grant J. [Center for Astrophysics, Department of Physics, University of Notre Dame, IN 46556 (United States)

    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.

  6. 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. PMID:24419383

  7. On Ambiguities in SAR Design

    NASA Technical Reports Server (NTRS)

    Freeman, Anthony

    2006-01-01

    Ambiguities are an aliasing effect caused by the periodic sampling of the scene backscatter inherent to pulsed radar systems such as Synthetic Aperture radar (SAR). In this paper we take a fresh look at the relationship between SAR range and azimuth ambiguity constraints on the allowable pulse repetition frequency (PRF) and the antenna length. We show that for high squint angles smaller antennas may be feasible in some cases. For some applications, the ability to form a synthetic aperture at high squint angles is desirable, but the size of the antenna causes problems in the design of systems capable of such operation. This is because the SAR system design is optimized for a side-looking geometry. In two examples design examples we take a suboptimum antenna size and examine the performance in terms of azimuth resolution and swath width as a function of squint angle. We show that for stripmap SARs, the swath width is usually worse for off-boresight squint angles, because it is severely limited by range walk, except in cases where we relax the spatial resolution. We consider the implications for the design of modest-resolution, narrow swath, scanning SAR scatterometers .

  8. 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

  9. Synthetic aperture radar range - Azimuth ambiguity design and constraints

    NASA Technical Reports Server (NTRS)

    Mehlis, J. G.

    1980-01-01

    Problems concerning the design of a system for mapping a planetary surface with a synthetic aperture radar (SAR) are considered. Given an ambiguity level, resolution, and swath width, the problems are related to the determination of optimum antenna apertures and the most suitable pulse repetition frequency (PRF). From the set of normalized azimuth ambiguity ratio curves, the designer can arrive at the azimuth antenna length, and from the sets of normalized range ambiguity ratio curves, he can arrive at the range aperture length or pulse repetition frequency. A procedure based on this design method is shown in an example. The normalized curves provide results for a SAR using a uniformly or cosine weighted rectangular antenna aperture.

  10. 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.

  11. Ambiguitys aftermath: How age differences in resolving lexical ambiguity affect subsequent comprehension

    PubMed Central

    Lee, Chia-lin; Federmeier, Kara D.

    2012-01-01

    When ambiguity resolution is difficult, younger adults recruit selection-related neural resources that older adults do not. To elucidate the nature of those resources and the consequences of their recruitment for subsequent comprehension, we embedded noun/verb homographs and matched unambiguous words in syntactically well-specified but semantically neutral sentences. Target words were followed by a prepositional phrase whose head noun was plausible for only one meaning of the homograph. Replicating past findings, younger but not older adults elicited sustained frontal negativity to homographs compared to unambiguous words. On the subsequent head nouns, younger adults showed plausibility effects in all conditions, attesting to successful meaning selection through suppression. In contrast, older adults showed smaller plausibility effects following ambiguous words and failed to show plausibility effects when the context picked out the homographs non-dominant meaning (i.e., they did not suppress the contextually-irrelevant dominant meaning). Meaning suppression processes, reflected in the frontal negativity, thus become less available with age, with consequences for subsequent comprehension. PMID:22321956

  12. Ellsbergs two-color experiment, portfolio inertia and ambiguity

    Microsoft Academic Search

    Sujoy Mukerji; Jean-Marc Tallon

    2003-01-01

    Results in this paper relate the observation of an interval of prices at which a decision maker (DM) strictly prefers to hold a zero position on an asset (termed portfolio inertia) to the DMs perception of the underlying payoff relevant events as ambiguous, as the term is defined in [Econometrica 69 (2001) 265]. The connection between portfolio inertia and ambiguity

  13. Evidence for Multiple Stages in the Processing of Ambiguous Words in Syntactic Contexts.

    ERIC Educational Resources Information Center

    Tanenhaus, Michael K.; And Others

    1979-01-01

    A variable time delay naming latency paradigm was used to investigate the processing of noun-verb lexical ambiguities (e.g., "watch") in syntactic contexts that biased either the noun or the verb reading. Results support a two-stage model in which all reading of ambiguous words are initially accessed, followed by suppression of inappropriate

  14. Lexical and Referential Cues to Sentence Interpretation: An Investigation of Children's Interpretations of Ambiguous Sentences

    ERIC Educational Resources Information Center

    Kidd, Evan; Bavin, Edith L.

    2005-01-01

    This paper reports on an investigation of children's (aged 3;5-9;8) comprehension of sentences containing ambiguity of prepositional phrase (PP) attachment. Results from a picture selection study (N=90) showed that children use verb semantics and preposition type to resolve the ambiguity, with older children also showing sensitivity to the

  15. Typology of Ambiguity on Representation of Information Problem: An Exploratory Study.

    ERIC Educational Resources Information Center

    Kim, Yang-woo

    2003-01-01

    Develops a framework explaining the need to disambiguate user inquiries to improve information systems and services. Categorizes a set of questions according to ambiguity type. Discusses three aspects of retrieval systems and services, based on results of categorization: increasing user input to make initial queries less ambiguous; reducing search

  16. 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),

  17. Resolving Number Ambiguities during Language Comprehension

    ERIC Educational Resources Information Center

    Bader, Markus; Haussler, Jana

    2009-01-01

    This paper investigates how readers process number ambiguous noun phrases in subject position. A speeded-grammaticality judgment experiment and two self-paced reading experiments were conducted involving number ambiguous subjects in German verb-end clauses. Number preferences for individual nouns were estimated by means of two questionnaire

  18. Ambiguity as a resource for design

    Microsoft Academic Search

    William W. Gaver; Jacob Beaver; Steve Benford

    2003-01-01

    Ambiguity is usually considered anathema in Human Computer Interaction. We argue, in contrast, that it is a resource for design that can be used to encourage close personal engagement with systems. We illustrate this with examples from contemporary arts and design practice, and distinguish three broad classes of ambiguity according to where uncertainty is located in the interpretative relationship linking

  19. Evidence against Competition during Syntactic Ambiguity Resolution

    ERIC Educational Resources Information Center

    van Gompel, R.P.G.; Pickering, M.J.; Pearson, J.; Liversedge, S.P.

    2005-01-01

    We report three eye-movement experiments that investigated whether alternative syntactic analyses compete during syntactic ambiguity resolution. Previous research (Traxler, Pickering, & Clifton, 1998; Van Gompel, Pickering, & Traxler, 2001) has shown that globally ambiguous sentences are easier to process than disambiguated sentences, suggesting

  20. ON RESOLUTION OF AMBIGUITY OF RASTER IMAGES

    E-print Network

    on the feasibility of automatic, intelligent retouching of partially damaged images. LOOK AT THE THREE PATTERNS BELOWON RESOLUTION OF AMBIGUITY OF RASTER IMAGES Vladimir Wojcik Technical Report # CS­95­01 March 1995 #12; ON RESOLUTION OF AMBIGUITY OF RASTER IMAGES 2 Vladimir Wojcik Technical Report CS­95­01 March

  1. 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

  2. Integral GPS and QZSS Ambiguity Resolution

    NASA Astrophysics Data System (ADS)

    Kubo, Nobuaki; Wu, Falin; Yasuda, Akio

    The US GPS and the planed Quasi Zenith Satellite System (QZSS) will enhance the capability of quickly resolving the integer cycle carrier phase ambiguities in precise differential positioning. The paper describes numerical analysis of the positioning performance of combined GPS-QZSS system. The current ambiguity resolution method is employed to resolve all cycle ambiguities of combined GPS-QZSS system. The performance of ambiguity resolution on a short baseline of 1 km in Tokyo is analyzed for different scenarios of the present GPS and combined future GPS-QZSS system. It is also analyzed in the Asian cities of Seoul, Beijing and Shanghai. The ambiguity fix percentage is adopted here for evaluating the performance of ambiguity resolution. It indicates that increasing the number of satellites has a benefit on the capability of getting quick ambiguity resolution. It also indicates that the ambiguity fix percentage with both GPS and QZSS is much higher than that with only GPS on the short-baseline operation.

  3. 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

  4. Effect of ambiguities on SAR picture quality

    NASA Technical Reports Server (NTRS)

    Korwar, V. N.; Lipes, R. G.

    1978-01-01

    The degradation of picture quality in a high-resolution, large-swath SAR mapping system caused by speckle, additive white Gaussian noise and range and azimuthal ambiguities occurring because of the nonfinite antenna pattern produced by a square aperture antenna was studied and simulated. The effect of the azimuth antenna pattern was accounted for by calculating the azimuth ambiguity function. Range ambiguities were accounted for by adding, to each pixel of interest, appropriate pixels at a range separation corresponding to one pulse repetition period, but attenuated by the antenna pattern. It is concluded that azimuth ambiguities do not cause any noticeable degradation (for large time bandwidth product systems, at least) but range ambiguities might.

  5. Clock ambiguity and the emergence of physical laws

    SciTech Connect

    Albrecht, Andreas; Iglesias, Alberto [Department of Physics, University of California at Davis, One Shields Avenue, Davis, California 95616 (United States)

    2008-03-15

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

  6. 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

  7. Give unto others: genetically unrelated cotton-top tamarin monkeys preferentially give food to those who altruistically give food back.

    PubMed

    Hauser, Marc D; Chen, M Keith; Chen, Frances; Chuang, Emmeline

    2003-11-22

    Altruistic food giving among genetically unrelated individuals is rare in nature. The few examples that exist suggest that when animals give food to unrelated others, they may do so on the basis of mutualistic or reciprocally altruistic relationships. We present the results of four experiments designed to tease apart the factors mediating food giving among genetically unrelated cotton-top tamarins (Saguinus oedipus), a cooperatively breeding New World primate. In experiment 1 we show that individuals give significantly more food to a trained conspecific who unilaterally gives food than to a conspecific who unilaterally never gives food. The apparent contingency of the tamarins' food-giving behaviour motivated the design of experiments 2-4. Results from all three experiments show that altruistic food giving is mediated by prior acts of altruistic food giving by a conspecific. Specifically, tamarins do not give food to unrelated others when the food received in the past represents the by-product of another's selfish actions (experiments 2 and 3) or when a human experimenter gives them food (experiment 4) as did the unilateral altruist in experiment 1. By contrast, if one tamarin gives another food without obtaining any immediate benefit, then the recipient is more likely to give food in return. Overall, results show that tamarins altruistically give food to genetically unrelated conspecifics, discriminate between altruistic and selfish actions, and give more food to those who give food back. Tamarins therefore have the psychological capacity for reciprocally mediated altruism. PMID:14667352

  8. Giving Teachers a Voice

    ERIC Educational Resources Information Center

    Dagenhart, Diana B.; O'Connor, Katherine A.; Petty, Teresa M.; Day, Barbara D.

    2005-01-01

    The authors report on a teacher survey that was conducted in North Carolina to determine the wants and needs of teachers in North Carolina. The survey had Likert-scaled quesitons about administrative support and professional development needs as well as information about professional and personal characteristics. The research was conducted to give

  9. Characteristics of velocity ambiguity for CINRAD-SA Doppler weather radars

    NASA Astrophysics Data System (ADS)

    Chu, Zhigang; Yin, Yan; Gu, Songshan

    2014-02-01

    The velocity ambiguity in Doppler weather radars has inhibited the application of wind field data for long time. One effective solution is software-based velocity dealiasing algorithm. In this paper, in order to better design, optimize and validate velocity dealiasing algorithms for CINRAD-SA, data from operational radars were used to statistically characterize velocity ambiguity. The analyzed characteristic parameters included occurrence rate, and inter-station, inter-type, temporal, and spatial distributions. The results show that 14.9% of cloud-rain files and 0.3% of clear-air files from CINRADSA radars are ambiguous. It is also found that echoes of weak convections have the highest occurrence rate of velocity ambiguity than any other cloud types, and the probability of ambiguity is higher in winter than in summer. A detailed inspection of the occurrence of ambiguity in various cases indicates that ambiguous points usually occur in areas with an elevation angle of 6.0, an azimuth of 70 or 250, radial distance of 50-60 km, and height of 5-6 km, and that 99.4% of ambiguous points are in the 1st-folding interval. Suggestions for performing dealiasing at different locations and different time points are provided.

  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. A study of the ambiguity in the solutions to the Diophantine equation for Chern numbers

    NASA Astrophysics Data System (ADS)

    Avron, J. E.; Kenneth, O.; Yehoshua, G.

    2014-05-01

    The Chern numbers for Hofstadter models with rational flux 2?p/q are partially determined by a Diophantine equation. A mod?q ambiguity remains. The resolution of this ambiguity is only known for the rectangular lattice with nearest neighbors hopping where it has the form of a window condition. We study a Hofstadter butterfly on the triangular lattice for which the resolution of ambiguity is open. In the model many pairs (p, q) satisfy a window condition which is shifted relative to the window of the square model. However, we also find pairs (p, q) where the Chern numbers do not belong to any contiguous window. This shows that the rectangular model and the one we study on the triangular lattice are not adiabatically connected: many gaps must close. Our results suggest the conjecture that the mod q ambiguity in the Diophantine equation generically reduces to a sign ambiguity.

  12. Resolving distance ambiguities towards 6.7 GHz methanol masers

    E-print Network

    Pandian, J D; Goldsmith, P F

    2008-01-01

    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. 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. We measured 21 cm HI absorption spectra using the Very Large Array in C and CnB configurations. A comparison of the maximum velocity of HI absorption with the source velocity and tangent point velocity was used to resolve the kinematic distance ambiguity. 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 st...

  13. Processing temporary syntactic ambiguity: The effect of contextual bias

    PubMed Central

    Mohamed, Mohamed Taha; Clifton, Charles

    2012-01-01

    This paper reports two experiments using sentences with a temporary ambiguity between a direct object and a sentence complement analysis that is resolved toward the normally-preferred direct object analysis. Post-verbal noun phrases in these sentences could be ambiguously attached as either a direct object or the subject of a sentence complement whereas in unambiguous versions of the sentences the subcategorization of the verb forced the direct object interpretation. Participants read these sentences in relatively long paragraph contexts, where the context supported the direct object analysis (preferred), supported the sentence complement analysis (unpreferred), or provided conflicting evidence about both analyses (conflicting). Self-paced reading times for ambiguous post-verbal noun phrases were almost equivalent to the reading times of their unambiguous counterparts, even in unpreferred and conflicted context conditions. However, time to read a following region, which forced the direct object interpretation, was affected by the interaction of verb subcategorization ambiguity and contextual support. The full pattern of results do not fit well with either an unelaborated single-analysis (garden path) model or a competitive constraint-satisfaction model, but are consistent with a race model in which multiple factors affect the speed of constructing a single initial analysis. PMID:21722057

  14. 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.

  15. Three types of ambiguity Lars Peter Hansen

    E-print Network

    Hansen, Lars Peter

    's ambiguity with a set of probability models. We thank Marco Bassetto, Anmol Bhandari, Jaroslav Borovicka Anmol Bhandari and Rui Cui for excellent computational assistance. 1 #12;A coherent multi-agent setting

  16. European starlings unriddle the ambiguous-cue problem

    PubMed Central

    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 trialsthe ambiguous-cue effect. We conducted two experiments with European starlings (Sturnus vulgaris) using Urcuioli and Michaleks (2007, Psychon B Rev 14, 658662) 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. PMID:25206346

  17. 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. PMID:25206346

  18. Role ambiguity, employee gender, and workplace friendship.

    PubMed

    Chen, Chien-Yu; Mao, Hsiao-Yen; Hsieh, An-Tien

    2012-06-01

    The importance of workplace friendship is recognized by researchers and practitioners, but its antecedents with respect to work roles are not well understood. Employees' gender might moderate a relationship between work roles and friendships. Data from a survey of 221 international tourist hotel employees showed that a key aspect of job support, role ambiguity, was negatively related to having workplace friendships. However, employees' gender did not moderate this relationship. Role clarity (the opposite of role ambiguity) may facilitate workplace friendships. PMID:22897079

  19. Give or Take?

    NSDL National Science Digital Library

    National 4-H Council

    2009-01-01

    In this outdoor activity, learners work in pairs using their sensesespecially touchto learn more about individual trees. After reading and discussing Shel Silverstein's storybook "The Giving Tree," learners conduct a field study of different trees. Each learner explores and answers questions about a particular tree's bark, age, smell, roots, leaves, and fruit, and what wildlife is found in or near the tree. In a latter part of the activity, learners wear blindfolds and try to identify their tree without using their sense of sight.

  20. 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.

  1. Autologous transplantation gives encouraging results for young adults with favorable-risk acute myeloid leukemia, but is not improved with gemtuzumab ozogamicin.

    PubMed

    Fernandez, Hugo F; Sun, Zhuoxin; Litzow, Mark R; Luger, Selina M; Paietta, Elisabeth M; Racevskis, Janis; Dewald, Gordon; Ketterling, Rhett P; Rowe, Jacob M; Lazarus, Hillard M; Tallman, Martin S

    2011-05-19

    We report the results of a prospective, randomized phase 3 trial evaluating the use of gemtuzumab ozogamicin (GO) in an intensive consolidation approach in 657 patients 17-60 years of age. Patients in first complete remission (CR1) after cytarabine and standard- or high-dose daunorubicin induction received 2 cycles of consolidation with high-dose cytarabine followed by peripheral blood progenitor cell collection. The 352 patients who entered consolidation were randomized to receive GO (n = 132) or not (n = 138) and then proceeded to autologous hematopoietic cell transplantation (HCT). GO was given to 67 patients. Median follow-up was 50.9 months. Results of the intention-to-treat analysis demonstrated a 4-year disease-free survival (DFS) of 33.6% versus 35.9% (P = .54) and an overall survival (OS) of 41.3% versus 41.9% (P = .52) for those randomized to receive GO versus no GO, respectively. Patients with favorable- and intermediate-risk acute myeloid leukemia (AML) treated with high-dose daunorubicin and autologous HCT had 4-year DFS rates of 60% and 40% and OS rates of 80% and 49.3%, respectively. For younger AML patients in CR1, autologous HCT should be considered in favorable- and intermediate-cytogenetic risk patients who do not have an allogeneic donor. The addition of a single dose of GO in this setting did not improve outcomes. PMID:21415269

  2. 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. PMID:23054426

  3. [A "I would like to give him my life": results of a psychological support intervention to caregivers of patients undergoing neuromotor rehabilitation].

    PubMed

    Moroni, L; Colangelo, M; Gall, M; Bertolotti, G

    2007-01-01

    A large proportion of patients hospitalised for severe neuromotor disorders are supported during the in-hospital rehabilitation program by family members. To target interventions of psychological support for these caregivers it can be of help to identify the causes of caregiver burden or specific needs. Anxiety and depression are common in caregivers and constitute, together with emotional distress caused by loneliness and reduced social activities, an important part of the caregiving burden. This paper presents results emerging from a clinical intervention of psychological support offered to caregivers of neuromotor patients, mainly post-stroke, who were undergoing a course of in-hospital rehabilitation. A psychometric assessment was carried out on a sample of 50 caregivers, spouses or children, at the beginning and end of the in-hospital rehabilitation period. The following questionnaires were used: the Revised Anxiety and Depression Scale (RADS), measuring anxiety and depression, the Caregiver Need Assessment (CNA), assessing needs related to the assisted patient, and the Family Strain Questionnaire (FSQ) for a broader assessment of the problems faced by caregivers. The Functional Independence Measure (FIM) was completed by the medical doctor. A significant reduction was found, between the beginning and end of the rehabilitation period, in the needs related to patient care on the CNA (p < 0.001). Caregiver females, in contrast to males, showed an improvement in mood compared to the beginning of the rehabilitation period (p < 0.05). About half of the sample had, at the beginning, a marked clinical level of anxiety while 22% of caregivers had a marked clinical level of depression. Caregivers who received intense psychological support, i.e. at least one interview with the psychologist per week, showed, in contrast to those who received 3-4 interviews during the entire rehabilitation period, a decline in thoughts of death (p < 0.05) and, in cases where baseline anxiety was above the clinical cut-off, a reduced level of anxiety (p < 0.05). At the beginning of rehabilitation, there emerged: higher anxiety scores in caregivers who live with their patient (p < 0.05) compared to those living alone or with others; an increase in depression scores in inverse proportion to the patient's age (p = 0.01); higher scores of emotional stress in spouses (p < 0.05) compared to children and in caregivers of patients with left hemisphere deficits (p < 0.05); a greater need for knowledge about the disease (p < 0.001) and more thoughts of death (p < 0.05) in caregivers of female patients. These characteristics may be considered "alarm signals" that should alert hospital medical staff to the need to seek psychological help for the caregiver. At the end of rehabilitation, a greater degree of psychological strain was observed in caregivers of patients with severe disability. High needs related to the assisted patient (p < 0.01), high scores of emotional stress (p < 0.05), problems of social involvement (p < 0.05) and thoughts of death about the patient (p < 0.05) were found in caregivers of patients who had persisting high motor disability or who were admitted for consequences of a left hemisphere lesion. High depression scores were also found in caregivers of patients with high residual cognitive disability (p < 0.05). This psychometric evaluation makes it possible to tailor the psychological support offered to the needs of each individual caregiver both during rehabilitation and in relation to eventual future developments. A multidisciplinary team approach to the caregiver can thus lead to a general reduction of caregiver strain. PMID:18575353

  4. SciGirls Summer Camp is the result of a partnership between the National High Magnetic Field Laboratory and our local public television station, WFSU. This camp gives middle school girls the opportunity to work with STEM professionals

    E-print Network

    McQuade, D. Tyler

    SciGirls Summer Camp is the result of a partnership between the National High Magnetic FieldGirls summer camps. SciGirls Summer Camp Introduces Middle School Girls to STEM Role Models at the Magnet Lab Laboratory and our local public television station, WFSU. This camp gives middle school girls the opportunity

  5. 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

  6. 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.

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

    PubMed

    Vitello, Sylvia; Warren, Jane E; Devlin, Joseph T; Rodd, Jennifer M

    2014-01-01

    Semantic ambiguity resolution is an essential and frequent part of speech comprehension because many words map onto multiple meanings (e.g., "bark," "bank"). Neuroimaging research highlights the importance of the left inferior frontal gyrus (LIFG) and the left posterior temporal cortex in this process but the roles they serve in ambiguity resolution are uncertain. One possibility is that both regions are engaged in the processes of semantic reinterpretation that follows incorrect interpretation of an ambiguous word. Here we used fMRI to investigate this hypothesis. 20 native British English monolinguals were scanned whilst listening to sentences that contained an ambiguous word. To induce semantic reinterpretation, the disambiguating information was presented after the ambiguous word and delayed until the end of the sentence (e.g., "the teacher explained that the BARK was going to be very damp"). These sentences were compared to well-matched unambiguous sentences. Supporting the reinterpretation hypothesis, these ambiguous sentences produced more activation in both the LIFG and the left posterior inferior temporal cortex. Importantly, all but one subject showed ambiguity-related peaks within both regions, demonstrating that the group-level results were driven by high inter-subject consistency. Further support came from the finding that activation in both regions was modulated by meaning dominance. Specifically, sentences containing biased ambiguous words, which have one more dominant meaning, produced greater activation than those with balanced ambiguous words, which have two equally frequent meanings. Because the context always supported the less frequent meaning, the biased words require reinterpretation more often than balanced words. This is the first evidence of dominance effects in the spoken modality and provides strong support that frontal and temporal regions support the updating of semantic representations during speech comprehension. PMID:25120445

  8. The spatial scale of perceptual memory in ambiguous figure perception

    E-print Network

    Ambiguous visual stimuli highlight the constructive nature of vision: perception alternates between two plausible interpretations of unchanging input. However, when a previously viewed ambiguous stimulus reappears, its earlier perception almost entirely determines the new interpretation; memory disambiguates the input. Here, we investigate the spatial properties of this perceptual memory, taking into account strong anisotropies in percept preference across the visual field. Countering previous findings, we show that perceptual memory is not confined to the location in which it was instilled. Rather, it spreads to noncontiguous regions of the visual field, falling off at larger distances. Furthermore, this spread of perceptual memory takes place in a frame of reference that is tied to the surface of the retina. These results place the neural locus of perceptual memory in retinotopically organized sensory cortical areas, with implications for the wider function of perceptual memory in facilitating stable vision in natural, dynamic environments.

  9. Range ambiguity clutter suppression for bistatic STAP radar

    NASA Astrophysics Data System (ADS)

    Xie, Wenchong; Zhang, Baihua; Wang, Yongliang; Zhu, Yong; Duan, Keqing; Li, Rongfeng

    2013-12-01

    Bistatic pulse-Doppler airborne radar has desirable properties such as the low probability of detection by other radars relative to its monostatic counterpart. However, the clutter characteristics of bistatic airborne radar are more complex than those of monostatic airborne radar. The clutter spectra not only vary severely with range, but also vary with bistatic configuration. In this article, the geometry model of bistatic airborne radar is given, and the approximate estimation expressions for clutter degrees of freedom (DOFs) are presented. Then a novel clutter suppression method for bistatic airborne radar with range ambiguity is presented. The method completes registration-based range ambiguity clutter compensation based on non-uniform sampling and the estimated clutter DOFs. The simulation results illustrate the performance improvement achieved for bistatic airborne radar.

  10. Acute stress affects risk taking but not ambiguity aversion

    PubMed Central

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

    2014-01-01

    Economic decisions are often made in stressful situations (e.g., at the trading floor), but the effects of stress on economic decision making have not been systematically investigated so far. The present study examines how acute stress influences economic decision making under uncertainty (risk and ambiguity) using financially incentivized lotteries. We varied the domain of decision making as well as the expected value of the risky prospect. Importantly, no feedback was provided to investigate risk taking and ambiguity aversion independent from learning processes. In a sample of 75 healthy young participants, 55 of whom underwent a stress induction protocol (Trier Social Stress Test for Groups), we observed more risk seeking for gains. This effect was restricted to a subgroup of participants that showed a robust cortisol response to acute stress (n = 26). Gambling under ambiguity, in contrast to gambling under risk, was not influenced by the cortisol response to stress. These results show that acute psychosocial stress affects economic decision making under risk, independent of learning processes. Our results further point to the importance of cortisol as a mediator of this effect. PMID:24834024

  11. 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

  12. Visual Working Memory Contents Bias Ambiguous Structure from Motion Perception

    PubMed Central

    Scocchia, Lisa; Valsecchi, Matteo; Gegenfurtner, Karl R.; Triesch, Jochen

    2013-01-01

    The way we perceive the visual world depends crucially on the state of the observer. In the present study we show that what we are holding in working memory (WM) can bias the way we perceive ambiguous structure from motion stimuli. Holding in memory the percept of an unambiguously rotating sphere influenced the perceived direction of motion of an ambiguously rotating sphere presented shortly thereafter. In particular, we found a systematic difference between congruent dominance periods where the perceived direction of the ambiguous stimulus corresponded to the direction of the unambiguous one and incongruent dominance periods. Congruent dominance periods were more frequent when participants memorized the speed of the unambiguous sphere for delayed discrimination than when they performed an immediate judgment on a change in its speed. The analysis of dominance time-course showed that a sustained tendency to perceive the same direction of motion as the prior stimulus emerged only in the WM condition, whereas in the attention condition perceptual dominance dropped to chance levels at the end of the trial. The results are explained in terms of a direct involvement of early visual areas in the active representation of visual motion in WM. PMID:23527141

  13. Perceptions of Boundary Ambiguity in the Process of Leaving an Abusive Partner.

    PubMed

    Khaw, Lyndal; Hardesty, Jennifer L

    2014-10-01

    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

  14. Enhancing lexical ambiguity resolution by brain polarization of the right posterior superior temporal sulcus.

    PubMed

    Peretz, Yael; Lavidor, Michal

    2013-04-01

    Previous studies have reported a hemispheric asymmetry in processing dominant (e.g., paper) and subordinate (e.g., farmer) associations of ambiguous words (pen). Here we applied sham and anodal Transcranial Direct Current Stimulation (tDCS) over Wernicke's area and its right homologue to test whether we can modulate the selective hemispheric expertise in processing lexical ambiguity. Ambiguous prime words were presented followed by target words that could be associated to the dominant or subordinate meaning of the prime in a semantic relatedness task. Anodal stimulation of the right Wernicke's area significantly decreased response time (RTs) to subordinate but not dominant associations compared to sham stimulation. There was also a complementary trend of faster responses to dominant associations following anodal stimulation of Wernicke's area. The results support brain asymmetry in processing lexical ambiguity and show that tDCS can enhance complex language processing even in a sample of highly literate individuals. PMID:22513342

  15. Facilitated lexical ambiguity processing by transcranial direct current stimulation over the left inferior frontal cortex.

    PubMed

    Ihara, Aya S; Mimura, Takanori; Soshi, Takahiro; Yorifuji, Shiro; Hirata, Masayuki; Goto, Tetsu; Yoshinime, Toshiki; Umehara, Hiroaki; Fujimaki, Norio

    2015-01-01

    Previous studies suggest that the left inferior frontal cortex is involved in the resolution of lexical ambiguities for language comprehension. In this study, we hypothesized that processing of lexical ambiguities is improved when the excitability of the left inferior frontal cortex is enhanced. To test the hypothesis, we conducted an experiment with transcranial direct current stimulation (tDCS). We investigated the effect of anodal tDCS over the left inferior frontal cortex on behavioral indexes for semantic judgment on lexically ambiguous and unambiguous words within a context. Supporting the hypothesis, the RT was shorter in the anodal tDCS session than in the sham session for ambiguous words. The results suggest that controlled semantic retrieval and contextual selection were facilitated by anodal tDCS over the left inferior frontal cortex. PMID:25208744

  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. SPONTANEOUS CP VIOLATION AND QUARK MASS AMBIGUITIES.

    SciTech Connect

    CREUTZ,M.

    2004-09-21

    I explore the regions of quark masses where CP will be spontaneously broken in the strong interactions. The boundaries of these regions are controlled by the chiral anomaly, which manifests itself in ambiguities in the definition of non-degenerate quark masses. In particular, the concept of a single massless quark is ill defined.

  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. Contextual Constraints on Ambiguous Word Recognition.

    ERIC Educational Resources Information Center

    Schvaneveldt, Roger W.; And Others

    Two major hypotheses are currently at issue concerning the effects of semantic context on ambiguous word recognition: (1) the selective-retrieval hypothesis (SRH) maintains that a single meaning is retrieved from memory, and (2) the nonselective-retrieval hypothesis maintains that all meanings are retrieved from memory. To help clear up this

  20. Ambiguity, Valuedness and Costs Helmut Seidl

    E-print Network

    Seidl, Helmut

    of finite tree automata, the valuedness of bottom--up finite state tree transducers and boundedness of cost of finite state devices. The ambiguity of an automaton is the least upper bound on the number of different language; transducers are called equivalent iff they define the same translation. For finite word automata

  1. Crossdressing and Gender Ambiguity in Shakespeare's Comedies

    Microsoft Academic Search

    Minzhen Jiang

    Crossdressing in Shakespeare 's comedies makes the heroines ' gender identity ambiguous: they are both men and women, owning both femininity and masculinity, thus crossdressing helps to deconstruct Renaissance gender stereotypes, the binary opposition of gender, and eventually, patriarchy. In Shakespeare 's most famous comedies, four women characters: Julia in The Two Gentlemen of Verona (1594), Portia in The Merchant

  2. 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

  3. Tense, Temporal Context, and Syntactic Ambiguity Resolution.

    ERIC Educational Resources Information Center

    Trueswell, John C.; Tanenhaus, Michael

    1991-01-01

    Three experiments investigating the use of temporal information in a reduced relative clause to interpret verb tense of the main clause found that subjects rapidly assessed temporal information to resolve tense ambiguity, demonstrating an incremental approach to comprehension that uses previous discourse to continuously update comprehension and

  4. On Removing Ambiguity in Text Understanding

    Microsoft Academic Search

    Simin Li; Yukihiro Itoh

    1998-01-01

    This paper discusses how to remove a kind of ambiguity in a text understanding system based on simulation. The system simulates some events mentioned in text on a world model and observes the behavior of the model during the simulation. Through these processes, it can recognize the other events mentioned implicitly. However, in case the system infers plural number of

  5. Is Quantum Electrodynamics free of ambiguities? D. Villarroel

    E-print Network

    Paris-Sud XI, Université de

    Is Quantum Electrodynamics free of ambiguities? D. Villarroel Avenida Tobalaba 3696,Puente Alto method, alternative to the customary one in quantum electrodynamics, for the calculation of tiny effects transparent the connection between classical and quantum electrodynamics. In particular, the ambiguities

  6. 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.

  7. 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

    2014-01-01

    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

  8. 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

  9. Neuronal Substrates for Choice Under Ambiguity, Risk, Gains, and Losses

    E-print Network

    Dukas, Reuven

    Paradigm for Choice Processing Under Ambiguity, Risk, Gains, and Losses A B Risk/Gains Ambiguity/Gains (RGNeuronal Substrates for Choice Under Ambiguity, Risk, Gains, and Losses Kip Smith John Dickhaut@csom.umn.edu kmccabe@gmu.edu pardo001@umn.edu Economic forces shape the behavior of individuals and institutions

  10. 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

  11. Primary School Children's Interpretations of Lexical Ambiguity in Mathematical Descriptions.

    ERIC Educational Resources Information Center

    Durkin, Kevin; Shire, Beatrice

    1991-01-01

    Investigates how children interpret lexical ambiguity in written descriptions of mathematical relationships. Finds that subjects are more likely to identify incorrectly the synonym of the dominant sense when the ambiguous word is used in its mathematical meaning than they are to identify the subordinate, mathematical sense when the ambiguous word

  12. 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

  13. WIND SCATTEROMETRY WITH IMPROVED AMBIGUITY SELECTION AND RAIN MODELING

    E-print Network

    Long, David G.

    WIND SCATTEROMETRY WITH IMPROVED AMBIGUITY SELECTION AND RAIN MODELING by David Draper of Engineering and Technology #12;ABSTRACT WIND SCATTEROMETRY WITH IMPROVED AMBIGUITY SELECTION AND RAIN MODELING to scatterometer estimate error: poor ambiguity selection, estimate uncertainty at low wind speeds, and rain

  14. Depression embodied: an ambiguous striving against fading.

    PubMed

    Danielsson, Louise; Rosberg, Susanne

    2014-09-23

    Although depression is associated to physical discomfort, meanings of the body in depression are rarely addressed in clinical research. Drawing on the concept of the lived body, this study explores depression as an embodied phenomenon. Using a hermeneutic phenomenological approach, the analysis of narrative-based interviews with 11 depressed adults discloses a thematic structure of an embodied process of an ambiguous striving against fading. Five subthemes elicit different dimensions of this process, interpreted as disabling or enabling: feeling estranged, feeling confined, feeling burdensome, sensing life and seeking belongingness. In relation to clinical practice, we suggest that the interdisciplinary team can focus on enhancing the enabling dimensions, for example through guided physical activities to support the patient to feel more alive, capable and connected. Moreover, we suggest that the treatment process benefits from an increased awareness of the ambiguity in the patient's struggle, acknowledging both destructive and recharging elements of the withdrawing, and the perceived conflict in-between. PMID:25251165

  15. Ambiguities in Quantizing a Classical System

    E-print Network

    Ian Redmount; Wai-Mo Suen; Kenneth Young

    1999-04-19

    One classical theory, as determined by an equation of motion or set of classical trajectories, can correspond to many unitarily {\\em in}equivalent quantum theories upon canonical quantization. This arises from a remarkable ambiguity, not previously investigated, in the construction of the classical (and hence the quantized) Hamiltonian or Lagrangian. This ambiguity is illustrated for systems with one degree of freedom: An arbitrary function of the constants of motion can be introduced into this construction. For example, the nonrelativistic and relativistic free particles follow identical classical trajectories, but the Hamiltonians or Lagrangians, and the canonically quantized versions of these descriptions, are inequivalent. Inequivalent descriptions of other systems, such as the harmonic oscillator, are also readily obtained.

  16. Are "drink responsibly" alcohol campaigns strategically ambiguous?

    PubMed

    Smith, Sandi W; Atkin, Charles K; Roznowski, JoAnn

    2006-01-01

    This article applies the concept of strategic ambiguity in examining viewer responses to brewer-sponsored "responsible drinking" television advertising campaigns. Strategically ambiguous messages are designed to engender diverse interpretations between varied audience segments, and these different selective perceptions should translate into relatively uniform positive corporate images. In this study, teenage and young adult respondents were shown a series of television spots from two leading alcohol companies. As predicted, there was a high degree of diversity in meanings of message content and campaign purpose derived by viewers, particularly among less sophisticated teenagers. Moreover, evaluative ratings of messages and sponsors were generally favorable and more uniform than interpretive responses. The research demonstrates how seemingly prohealth messages can serve to subtly advance both industry sales and public relations interests. PMID:16813484

  17. 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

  18. 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 the GIF resolution hypothesis is completely valid for non-rotational periodic motions. Additionally, human perception of translation is impaired without visual or spatial reference. The performance of ground-base subjects in estimating tilt after brief training is comparable with that of crewmembers without training.

  19. [Analysis of ambiguities in HLA sequencing-based typing and its solutions].

    PubMed

    Wang, Daming; He, Liumei; Zou, Hongyan; Gao, Suqing; Deng, Zhihui

    2015-02-10

    OBJECTIVE To investigate the number and ratio of ambiguous allele combinations from human leukocyte antigen (HLA) confirmatory test by sequencing based typing for unrelated donor marrow transplantation, and to establish an efficient strategy for identifying such ambiguities. METHODS A total of 650 donor-receipt samples were genotyped for 5 loci of the HLA gene using an Atria SBT commercial kit. Exons 2, 3 and 4 of HLA-A, -B and -C, exon 2 of HLA-DRB1 and exons 2 and 3 of HLA-DQB1 were tested by routine HLA genotyping. The ratio of usual ambiguous allele combination was calculated. The ambiguities were subjected to further confirmatory test by PCR-SSP or PCR-SBT retest at outside of the routine sequencing region. RESULTS Among the 650 tested samples, the ratio of ambiguity at HLA-A, B, C, DRB1 and DQB1 were 76.31% (496/650), 91.08% (592/650), 97.69% (635/650), 88.62% (576/650) and 43.38% (141/650), respectively. A total of 36 ambiguous allele combinations inside the routine sequencing region and 22 ambiguous allele combinations outside of the routine sequencing region were discovered. After removing rare alleles based on the Chinese common and well documented (CWD) Allele Table (Version 1.01), 9 ambiguous CWD allele combinations inside the routine sequencing region, including 3 located in HLA-B, HLA-C and 1 located in other three HLA loci were found. Ten ambiguous CWD allele combinations outside of the routine sequencing region, including 4 located in HLA-C, -DRB1 and 1 in HLA-A, -B respectively were determined. All samples with ambiguous CWD allele combinations could be distinguished by high-resolution PCR-SSP commercial kits or PCR SBT retest at outside of the routine sequencing region. CONCLUSION The common and well documented allele combinations in sequencing-based typing at five HLA loci have been analyzed. Our strategy may provide valuable information for more efficient, low cost and accurate method for high resolution genotyping of HLA genes. PMID:25636098

  20. Carrier phase ambiguity resolution for the Global Positioning System applied to geodetic baselines up to 2000 km

    NASA Technical Reports Server (NTRS)

    Blewitt, Geoffrey

    1989-01-01

    A technique for resolving the ambiguities in the GPS carrier phase data (which are biased by an integer number of cycles) is described which can be applied to geodetic baselines up to 2000 km in length and can be used with dual-frequency P code receivers. The results of such application demonstrated that a factor of 3 improvement in baseline accuracy could be obtained, giving centimeter-level agreement with coordinates inferred by very-long-baseline interferometry in the western United States. It was found that a method using pseudorange data is more reliable than one using ionospheric constraints for baselines longer than 200 km. It is recommended that future GPS networks have a wide spectrum of baseline lengths (ranging from baselines shorter than 100 km to those longer than 1000 km) and that GPS receivers be used which can acquire dual-frequency P code data.

  1. How Do Information Ambiguity and Timing of Contextual Information Affect Managers Goal Congruence in Making Investment Decisions in Good Times vs. Bad Times?

    Microsoft Academic Search

    Joanna L. Y. Ho; L. Robin Keller; Pamela Keltyka

    2005-01-01

    Information ambiguity is prevalent in organizations and may influence management decisions. This study draws upon research on information bias and ambiguity research to empirically test how information ambiguity and non-financial factors (e.g., interpersonal information) affect managers capital budgeting decisions when in good vs. bad times. Ninety-two managers completed two experiments. In Experiment One, the information was presented sequentially. Our results

  2. Measurement of sin(2beta) in Tree-dominated B^0-Decays and Ambiguity Removal

    SciTech Connect

    Lacker, Heiko

    2007-03-05

    The most recent results from the B-factories on the time-dependent CP asymmetries measured in B{sup 0}-decays mediated by b {yields} c{bar c}s quark-transitions are reviewed. The Standard Model interpretation of the results in terms of the parameter sin 2{beta} leads to a four-fold ambiguity on the unitarity triangle {beta} which can be reduced to a two-fold ambiguity by measuring the sign of the parameter cos 2{beta}. The results on cos 2{beta} obtained so far are reviewed.

  3. Measurement of Sin(2beta) in Tree Dominated B0 Decays And Ambiguity Removal

    SciTech Connect

    Lacker, H.; /Dresden, Tech. U.

    2007-11-20

    The most recent results from the B-factories on the time-dependent CP asymmetries measured in B{sup 0}-decays mediated by b {yields} c{bar c}s quark-transitions are reviewed. The Standard Model interpretation of the results in terms of the parameter sin 2{beta} leads to a four-fold ambiguity on the unitarity triangle {beta} which can be reduced to a two-fold ambiguity by measuring the sign of the parameter cos 2{beta}. The results on cos2{beta} obtained so far are reviewed.

  4. 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

  5. Ambiguous Discrimination of General Quantum Operations

    NASA Astrophysics Data System (ADS)

    Li, L-Jun

    2014-12-01

    We consider the problem of discriminating general quantum operations. Using the definition of mapping operator to vector, and by some calculating skills, we derive an explicit formulation as a new bound on the minimum-error probability for ambiguous discrimination between arbitrary m quantum operations. This formulation consists only of Kraus-operators, the dimension, and the priori probabilities of the discriminated quantum operations, and is independent of input states. To some extent, we further generalize the bounds on the minimum-error probability for discriminating mixed states to quantum operations.

  6. 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

  7. Give.org Charity Standards

    NSDL National Science Digital Library

    A useful service available on the web from the Better Business Bureaus Wise Giving Alliance. The service "promotes ethical standards within the charitable community, provides information to the public on charitable organizations, and educates individual and corporate donors on wise giving." Give.org issues reports on non-profit organizations based on the number of inquiries received for an organization. Included with most reports is information on an organization's "background, current programs, governing body, fund-raising practices, tax-exempt status, finances, and indication of whether or not the organization complies with the BBB Standards for Charitable Solicitations."

  8. Lexical and prosodic effects on syntactic ambiguity resolution in aphasia.

    PubMed

    DeDe, Gayle

    2012-10-01

    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

  9. 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.

  10. 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.

  11. 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

  12. How to Safely Give Acetaminophen

    MedlinePLUS

    ... 2 tablets 72-95 lbs. (11 years) 3 tablets Reviewed by: Steve Dowshen, MD, and Karla R. Hughes, RPh Date ... Using Them Safely Headaches How to Safely Give Ibuprofen Why Do I Have Pain? A Kid's Guide ...

  13. Ambiguity resolution in systems using Omega for position location

    NASA Technical Reports Server (NTRS)

    Frenkel, G.; Gan, D. G.

    1974-01-01

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

  14. Mechanisms of Semantic Ambiguity Resolution: Insights from Speech Perception

    Microsoft Academic Search

    Daniel Mirman

    2008-01-01

    The speech signal is inherently ambiguous and all computational and behavioral research on speech perception has implicitly\\u000a or explicitly investigated the mechanism of resolution of this ambiguity. It is clear that context and prior probability (i.e.,\\u000a frequency) play central roles in resolving ambiguities between possible speech sounds and spoken words (speech perception)\\u000a as well as between meanings and senses of

  15. 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.

  16. Global Positioning System Integer Ambiguity Resolution without Attitude Knowledge

    E-print Network

    Crassidis, John L.

    1 Global Positioning System Integer Ambiguity Resolution without Attitude Knowledge John L measurements from Global Positioning System (GPS) receivers provides a novel approach for three-axis attitude

  17. Errors Analysis in GPS Precise Point Positioning: Impact of Ambiguity Fixing

    NASA Astrophysics Data System (ADS)

    Perosanz, F.; Fund, F.; Mercier, F.; Loyer, S.; Capdeville, H.

    2010-12-01

    GNSS geodetic positioning using the classical double-difference approach may have some limitations. For example, fixing ambiguities can be challenging for long baselines, while processing short baseline only give the relative displacement between the two stations. In this context and thanks to the continuous improvement of IGS GNSS orbit and clock products, the Precise Point Positioning (PPP) technique appears in the literature as a powerful alternative. If all local Earth deformations are correctly taken into account, residuals of position time series may be used to assess the processing quality in terms of receiver performance and environment, constellation orbits and clocks error projection, and processing options pertinence. The main limitation of most of the current PPP processing strategies is that ambiguities can not be fixed to integer values. However, Mercier et al. (2008) demonstrated that GPS satellite electronic biases can be a priori identified in such a way that using a consistent set of GPS orbits, clocks and biases, phase ambiguities recover their integer nature. The CNES-CLS IGS Analysis Center is being providing such set of data since August 2010. This study evaluate the performance of PPP in front of the nowadays requirements of geodesy. We processed data from several IGS sites in order to compute coordinate series on a daily basis but also at higher frequencies (down to 30 second interval). We investigated both the impact of the processing batch duration from hours to several days and the cut-off elevation angle. Various spurious non geophysical signals (random, periodic, jumps...)appeared in our series. Especially artificial "midnight jumps" when adopting the usual 24-hours batch solutions (when satellite passes were cut at 0h). The impact of fixing ambiguities on PPP solutions has been investigated. We demonstrate that most of the artifacts affecting floating PPP solutions disappeared when ambiguities were fixed.

  18. 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. PMID:23356360

  19. Construal processes and trait ambiguity: implications for self-peer agreement in personality judgment.

    PubMed

    Hayes, A F; Dunning, D

    1997-03-01

    The relationship between trait ambiguity and self-peer agreement in personality judgment was examined. In Study 1, self-peer agreement was lower on ambiguous traits (those with many behavioral referents) than on unambiguous ones (those with few behavioral referents). This finding was partially moderated by the level of friendship between peers. These results suggest that people disagree in their judgments because they use idiosyncratic trait definitions when making judgments on ambiguous traits. Study 2 tested this explanation by exploring self-peer agreement when participant pairs were forced to use the same trait definition versus different ones when judging themselves and each other. Forcing participants to use the same trait definition increased the degree to which their judgments covaried with one another. Discussion centers on the cognitive and motivational forces that can influence the degree to which personality judgments differ. PMID:9120790

  20. Human middle temporal cortex, perceptual bias, and perceptual memory for ambiguous three-dimensional motion.

    PubMed

    Brascamp, Jan W; Kanai, Ryota; Walsh, Vincent; van Ee, Raymond

    2010-01-13

    When faced with inconclusive or conflicting visual input human observers experience one of multiple possible perceptions. One factor that determines perception of such an ambiguous stimulus is how the same stimulus was perceived on previous occasions, a phenomenon called perceptual memory. We examined perceptual memory of an ambiguous motion stimulus while applying transcranial magnetic stimulation (TMS) to the motion-sensitive areas of the middle temporal cortex (hMT+). TMS increased the predominance of whichever perceptual interpretation was most commonly reported by a given observer at baseline, with reduced perception of the less favored interpretation. This increased incidence of the preferred percept indicates impaired long-term buildup of perceptual memory traces that normally act against individual percept biases. We observed no effect on short-term memory traces acting from one presentation to the next. Our results indicate that hMT+ is important for the long-term buildup of perceptual memory for ambiguous motion stimuli. PMID:20071541

  1. Is "?" 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. PMID:23871860

  2. Reliable non-ambiguity range extension with dual-comb simultaneous operation in absolute distance measurements

    NASA Astrophysics Data System (ADS)

    Zhang, Hongyuan; Wei, Haoyun; Wu, Xuejian; Yang, Honglei; Li, Yan

    2014-12-01

    We report an absolute distance measurement scheme using two simultaneous optical frequency combs with different repetition rates for reliable non-ambiguity range extension. Since the non-ambiguity range extension is susceptible to distance drift during the repetition rate adjustment, pulse trains with two different repetition rates are coupled and directed simultaneously onto a target for coincident distance measurement. The simultaneous measurement avoids the process of adjusting the repetition rate and suppresses the influence of distance drift therein. The distances measured by the two repetition rates are distinguished by type II second harmonic generation. Target movement and atmospheric variation are made to imitate the distance drift, and experimental results show that the non-ambiguity range extension remains effective along the measurement.

  3. Threat processing in generalized social phobia: an investigation of interpretation biases in ambiguous facial affect.

    PubMed

    Jusyte, Aiste; Schnenberg, Michael

    2014-06-30

    Facial affect is one of the most important information sources during the course of social interactions, but it is susceptible to distortion due to the complex and dynamic nature. Socially anxious individuals have been shown to exhibit alterations in the processing of social information, such as an attentional and interpretative bias toward threatening information. This may be one of the key factors contributing to the development and maintenance of anxious psychopathology. The aim of the current study was to investigate whether a threat-related interpretation bias is evident for ambiguous facial stimuli in a population of individuals with a generalized Social Anxiety Disorder (gSAD) as compared to healthy controls. Participants judged ambiguous happy/fearful, angry/fearful and angry/happy blends varying in intensity and rated the predominant affective expression. The results obtained in this study do not indicate that gSAD is associated with a biased interpretation of ambiguous facial affect. PMID:24656896

  4. 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 results suggest that restricting identifications to the family level is not a good method of resolving ambiguous taxa, whereas generating OTUs works well provided that documentation issues are addressed. ?? 2007 by The North American Benthological Society.

  5. Synonymousnon-synonymous mutation rates between sequences containing ambiguous nucleotides (Syn-SCAN)

    PubMed Central

    Gonzales, Matthew J.; Dugan, Jonathan M.; Shafer, Robert W.

    2015-01-01

    Summary Direct PCR sequencing on genetic material containing allelic mixtures results in sequences containing ambiguous nucleotides. Because codons exhibiting allelic mixtures present evidence of evolutionary pressure, it is important to include this information in the assessment of codon synonymy. We developed a program, `SynonymousNonsynonymous Mutation Rates between Sequences Containing Ambiguous Nucleotides' (Syn-SCAN), that calculates synonymous and non-synonymous substitution rates using a model that includes allelic mixtures. Availability Syn-SCAN is implemented on the web and can be downloaded from http://hivdb.stanford.edu. PMID:12075026

  6. Risk, ambiguity and quantum decision theory

    E-print Network

    Riccardo Franco

    2007-11-06

    In the present article we use the quantum formalism to describe the effects of risk and ambiguity in decision theory. The main idea is that the probabilities in the classic theory of expected utility are estimated probabilities, and thus do not follow the classic laws of probability theory. In particular, we show that it is possible to use consistently the classic expected utility formula, where the probability associated to the events are computed with the equation of quantum interference. Thus we show that the correct utility of a lottery can be simply computed by adding to the classic expected utility a new corrective term, the uncertainty utility, directly connected with the quantum interference term.

  7. 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.

  8. 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

  9. Decreasing Ambiguity of the Safety Culture Concept

    SciTech Connect

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

    2001-06-17

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

  10. Processes in the Resolution of Ambiguous Words: Towards a Model of Selective Inhibition. Cognitive Science Program, Technical Report No. 86-6.

    ERIC Educational Resources Information Center

    Yee, Penny L.

    This study investigates the role of specific inhibitory processes in lexical ambiguity resolution. An attentional view of inhibition and a view based on specific automatic inhibition between nodes predict different results when a neutral item is processed between an ambiguous word and a related target. Subjects were 32 English speakers with normal

  11. 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

  12. Give your parents some credit.

    E-print Network

    Talley, Lynne D.

    Give your parents some credit. Are you an undergraduate in your first four years at UC and attend school at least half time? You or your parents may be able to get up to $2,500 in tax credit for your to your email in January. And, make sure you forward it to your parents if they claim you as a dependent

  13. 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)

  14. A NOTE ON GROUP CONTRACTIONS AND RADAR AMBIGUITY FUNCTIONS

    E-print Network

    Miller, Willard

    the expansion formula for the target distribution function in the narrowband case arises as a limit how the narrowband cross ambiguity function arises as a limit of the wideband crossambiguity function. We also demonstrate how the expansion formula for the target distribution function

  15. 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

  16. 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

  17. Detecting the Ambiguity of Sentences: Relationship to Early Reading Skill

    ERIC Educational Resources Information Center

    Cairns, Helen Smith; Waltzman, Dava; Schlisselberg, Gloria

    2004-01-01

    The authors of this article report on a preliminary study of 18, 4- and 5-year-old children, followed by a longitudinal study of 44 children, who were tested in the first, second, and third grades. The children's ability to detect the ambiguity of lexically ambiguous sentences (e. g., "The children saw the bat lying by the fence") and structurally

  18. Personality Type, Tolerance of Ambiguity, and Vocabulary Retention in CALL.

    ERIC Educational Resources Information Center

    Grace, Caroline

    1998-01-01

    A study (n=181 college students) examined effects of lexical ambiguity in computer-assisted language learning (CALL) on beginning second-language learners, focusing on whether personality type affects retention of second-language vocabulary independent of translation issues and in an ambiguous CALL context. Findings support the need for beginning

  19. 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

  20. 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

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

    ERIC Educational Resources Information Center

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

    2009-01-01

    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

  2. Association and Uncertainty: Norms of Association to Ambiguous Words.

    ERIC Educational Resources Information Center

    Perfetti, Charles A.; And Others

    Norms of free association to common ambiguous English words are reported. Responses were categorized on the basis of sense relevance. On this basis, the sense dominance of the words was quantified, and the degree of ambiguity associated with each word estimated by the information measure U. This publication will be of interest primarily to

  3. Method of resolving radio phase ambiguity in satellite orbit determination

    Microsoft Academic Search

    Charles C. Councelman III; Richard I. Abbot

    1989-01-01

    For satellite orbit determination, the most accurate observable available today is microwave radio phase, which can be differenced between observing stations and between satellites to cancel both transmitter- and receiver-related errors. For maximum accuracy, the integer cycle ambiguities of the doubly differenced observations must be resolved. To perform this ambiguity resolution, a bootstrapping strategy is proposed. This strategy requires the

  4. 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

  5. Lexical Ambiguity Resolution: Word Processing, Recognition and Context Effect

    ERIC Educational Resources Information Center

    Kilickaya, Ferit

    2007-01-01

    In the paper the lexical ambiguity resolution is presented. The paper is specifically focused on the processing of words, models of word recognition, context effect, trying to find an answer to how the reader-listener determines the contextually appropriate meaning of a word. Ambiguity resolution is analyzed and explored in two perspectives: the

  6. The Role of Verb Information in Syntactic Ambiguity Resolution.

    ERIC Educational Resources Information Center

    Kennison, Shelia M.

    This study, consisting of two experiments, investigated the role of verb information in resolving ambiguous noun phrases (NPs) in reading comprehension. Both experiments extended earlier studies. The first measured and compared reading time for sentences containing temporarily ambiguous subject complements and unambiguous complements, which were

  7. 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

  8. 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

  9. 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

  10. Boundary ambiguity, coping patterns and depression in mothers caring for children with epilepsy in Taiwan

    Microsoft Academic Search

    Pei-Fan Mu; Hsun-Chih Kuo; Kai-Ping Chang

    2005-01-01

    A descriptive correlational study was designed to examine the relationships between boundary ambiguity, coping strategies and depression in mothers caring for children with epilepsy. A total of 316 mothers were recruited from three medical centers in Taiwan. A pilot study established the reliability and validity of the Chinese language version of the Coping Health Inventory for Parents (CHIP). Results showed

  11. 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

  12. Ambiguity as Social Control: The Salience of Sex-Status in Professional Settings.

    ERIC Educational Resources Information Center

    Epstein, Cynthia Fuchs

    Contradictions in belief and ambiguities rooted in culture cause confusion without many being aware of its sources. The resulting strain is unevenly distributed. The problems women face are complex and have roots in the conflicting views of women's worth, woman's place as well as the time overloads of role demands and the conflict in the priority

  13. Frequency Effects on the Processing of Ambiguous Words in Sentence Contexts.

    ERIC Educational Resources Information Center

    Lucas, Margery M.

    1987-01-01

    Study investigated the processing of ambiguous words that varied in frequency of use of their multiple interpretations. Results indicate that, whereas lexical access is an autonomous process, selection of the appropriate interpretation is a post-lexical process that is influenced by frequency information and context. (MM)

  14. Sidestepping Garden Paths: Assessing the Contributions of Syntax, Semantics, and Plausibility in Resolving Ambiguities.

    ERIC Educational Resources Information Center

    Ni, Weijia; And Others

    1996-01-01

    Explores the prediction of the referential theory, which maintains that the relative complexity of discourse representations plays a key role in determining the perceiver's immediate parsing preferences. Results indicate that semantic/referential principles are applied immediately in an online ambiguity resolution and preempt general world

  15. 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,

  16. Sequence Effects in Solving Knowledge-Rich Problems: The Ambiguous Role of Surface Similarities

    E-print Network

    Paris-Sud XI, Université de

    Sequence Effects in Solving Knowledge-Rich Problems: The Ambiguous Role of Surface Similarities Tuebingen, Germany Abstract Sequence effects are said to occur whenever the problem- solving performance sequence effects as a result of (a) learning during solving a problem and of (b) transferring the learned

  17. Propagation and wavefront ambiguity of linear nondiffracting beams

    NASA Astrophysics Data System (ADS)

    Grunwald, R.; Bock, M.

    2014-02-01

    Ultrashort-pulsed Bessel and Airy beams in free space are often interpreted as "linear light bullets". Usually, interconnected intensity profiles are considered a "propagation" along arbitrary pathways which can even follow curved trajectories. A more detailed analysis, however, shows that this picture gives an adequate description only in situations which do not require to consider the transport of optical signals or causality. To also cover these special cases, a generalization of the terms "beam" and "propagation" is necessary. The problem becomes clearer by representing the angular spectra of the propagating wave fields by rays or Poynting vectors. It is known that quasi-nondiffracting beams can be described as caustics of ray bundles. Their decomposition into Poynting vectors by Shack-Hartmann sensors indicates that, in the frame of their classical definition, the corresponding local wavefronts are ambiguous and concepts based on energy density are not appropriate to describe the propagation completely. For this reason, quantitative parameters like the beam propagation factor have to be treated with caution as well. For applications like communication or optical computing, alternative descriptions are required. A heuristic approach based on vector field based information transport and Fourier analysis is proposed here. Continuity and discontinuity of far field distributions in space and time are discussed. Quantum aspects of propagation are briefly addressed.

  18. Implicit perceptual memory modulates early visual processing of ambiguous images.

    PubMed

    de Jong, Maartje C; Brascamp, Jan W; Kemner, Chantal; van Ee, Raymond; Verstraten, Frans A J

    2014-07-23

    The way we perceive the present visual environment is influenced by past visual experiences. Here we investigated the neural basis of such experience dependency. We repeatedly presented human observers with an ambiguous visual stimulus (structure-from-motion) that can give rise to two distinct perceptual interpretations. Past visual experience is known to influence the perception of such stimuli. We recorded fast dynamics of neural activity shortly after stimulus onset using event-related electroencephalography. The number of previous occurrences of a certain percept modulated early posterior brain activity starting as early as 50 ms after stimulus onset. This modulation developed across hundreds of percept repetitions, reflecting several minutes of accumulating perceptual experience. Importantly, there was no such modulation when the mere number of previous stimulus presentations was considered regardless of how they were perceived. This indicates that the effect depended on previous perception rather than previous visual input. The short latency and posterior scalp location of the effect suggest that perceptual history modified bottom-up stimulus processing in early visual cortex. We propose that bottom-up neural responses to a given visual presentation are shaped, in part, by feedback modulation that occurred during previous presentations, thus allowing these responses to be biased in light of previous perceptual decisions. PMID:25057199

  19. Method of resolving radio phase ambiguity in satellite orbit determination

    NASA Technical Reports Server (NTRS)

    Councelman, Charles C., III; Abbot, Richard I.

    1989-01-01

    For satellite orbit determination, the most accurate observable available today is microwave radio phase, which can be differenced between observing stations and between satellites to cancel both transmitter- and receiver-related errors. For maximum accuracy, the integer cycle ambiguities of the doubly differenced observations must be resolved. To perform this ambiguity resolution, a bootstrapping strategy is proposed. This strategy requires the tracking stations to have a wide ranging progression of spacings. By conventional 'integrated Doppler' processing of the observations from the most widely spaced stations, the orbits are determined well enough to permit resolution of the ambiguities for the most closely spaced stations. The resolution of these ambiguities reduces the uncertainty of the orbit determination enough to enable ambiguity resolution for more widely spaced stations, which further reduces the orbital uncertainty. In a test of this strategy with six tracking stations, both the formal and the true errors of determining Global Positioning System satellite orbits were reduced by a factor of 2.

  20. A neural wayfinding mechanism adjusts for ambiguous landmark information.

    PubMed

    Janzen, Gabriele; Jansen, Clemens

    2010-08-01

    Objects along a route can serve as crucial landmarks that facilitate successful navigation. Previous functional magnetic resonance imaging (fMRI) evidence indicated that the human parahippocampal gyrus automatically distinguishes between objects placed at navigationally relevant (decision points) and irrelevant locations (non-decision points). This storage of relevant objects can provide a neural mechanism underlying successful navigation. However, only objects that actually support wayfinding need to be stored. Objects can also provide misleading information if similar objects appear at different locations along a route. An efficient mechanism needs to specifically adjust for ambiguous landmark information. We investigated this by placing identical objects twice in a virtual labyrinth at places with the same as well as with a different navigational relevance. Twenty right-handed volunteers moved through a virtual maze. They viewed the same object either at two different decision points, at two different non-decision points, or at a decision as well as at a non-decision point. Afterwards, event-related fMRI data were acquired during object recognition. Participants decided whether they had seen the objects in the maze or not. The results showed that activity in the parahippocampal gyrus was increased for objects placed at a decision and at a non-decision point as compared to objects placed at two non-decision points. However, ambiguous information resulting from the same object placed at two different decision points revealed increased activity in the right middle frontal gyrus. These findings suggest a neural wayfinding mechanism that differentiates between helpful and misleading information. PMID:20381625

  1. Conformational bias imposed by source microseeds results in structural ambiguity.

    PubMed

    Tzarum, Netanel; Engelberg, David; Livnah, Oded

    2011-08-01

    The p38 MAP kinase pathway is an essential component of numerous cellular signalling networks which are usually activated in response to extracellular environmental stress conditions. In addition to the canonical activation, several alternative activation pathways have been identified for p38; one of these, in which p38 is initially phosphorylated on Tyr323 and consequently autoactivated, is exclusive to T cells and is induced by TCR activation. Intrinsically active and inactive mutants at position 323 have been developed in order to evaluate the structural changes that occur upon TCR-induced activation. In order to promote crystal growth, cross streak-seeding techniques were utilized. This technique has gained popularity in promoting crystal growth when spontaneous nucleation induces critical defects or is being entirely hindered. The crystal characteristics of some mutants were highly similar to those of the wild-type source seeds (form A). In contrast, other mutants crystallized spontaneously with a different space group and molecular packing (form B). One of the active mutants (Y323T) crystallized in both crystal forms, displaying different packing characteristics and significant differences in molecular conformation that were clearly dictated by the source seeds. This implies that the source seeds used in cross streak-seeding could, in some cases, impose bias on the structural outcome of the studied molecule. Such incidents could occur when the conformational freedom permits crystal packing while not reflecting the authentic structure. PMID:21821885

  2. Giving Birth Like A Girl

    Microsoft Academic Search

    Karin A. Martin

    2003-01-01

    Relational, selfless, caring, polite, nice, and kind are not how we imagine a woman giving birth in U.S. culture. Rather, we picture her as screaming, yelling, self-centered, and demanding drugs or occasionally as numbed and passive from pain-killing medication. Using in-depth interviews with women about their labor and childbirth, the author presents data to suggest that white, middle-class, heterosexual women

  3. Validation of statistical imputation of allele-level multilocus phased genotypes from ambiguous HLA assignments.

    PubMed

    Madbouly, A; Gragert, L; Freeman, J; Leahy, N; Gourraud, P-A; Hollenbach, J A; Kamoun, M; Fernandez-Vina, M; Maiers, M

    2014-09-01

    Genetic matching for loci in the human leukocyte antigen (HLA) region between a donor and a patient in hematopoietic stem cell transplantation (HSCT) is critical to outcome; however, methods for HLA genotyping of donors in unrelated stem cell registries often yield results with allelic and phase ambiguity and/or do not query all clinically relevant loci. We present and evaluate a statistical method for in silico imputation of HLA alleles and haplotypes in large ambiguous population data from the Be The Match() Registry. Our method builds on haplotype frequencies estimated from registry populations and exploits patterns of linkage disequilibrium (LD) across HLA haplotypes to infer high resolution HLA assignments. We performed validation on simulated and real population data from the Registry with non-trivial ambiguity content. While real population datasets caused some predictions to deviate from expectation, validations still showed high percent recall for imputed results with average recall >76% when imputing HLA alleles from registry data. We simulated ambiguity generated by several HLA genotyping methods to evaluate the imputation performance on several levels of typing resolution. On average, imputation percent recall of allele-level HLA haplotypes was >95% for allele-level typing, >92% for intermediate resolution typing and >58% for serology (low-resolution) typing. Thus, allele-level HLA assignments can be imputed through the application of a set of statistical and population genetics inferences and with knowledge of haplotype frequencies and self-identified race and ethnicities. PMID:25040134

  4. 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

  5. Quadri-stability of a spatially ambiguous auditory illusion.

    PubMed

    Bainbridge, Constance M; Bainbridge, Wilma A; Oliva, Aude

    2014-01-01

    In addition to vision, audition plays an important role in sound localization in our world. One way we estimate the motion of an auditory object moving towards or away from us is from changes in volume intensity. However, the human auditory system has unequally distributed spatial resolution, including difficulty distinguishing sounds in front vs. behind the listener. Here, we introduce a novel quadri-stable illusion, the Transverse-and-Bounce Auditory Illusion, which combines front-back confusion with changes in volume levels of a nonspatial sound to create ambiguous percepts of an object approaching and withdrawing from the listener. The sound can be perceived as traveling transversely from front to back or back to front, or "bouncing" to remain exclusively in front of or behind the observer. Here we demonstrate how human listeners experience this illusory phenomenon by comparing ambiguous and unambiguous stimuli for each of the four possible motion percepts. When asked to rate their confidence in perceiving each sound's motion, participants reported equal confidence for the illusory and unambiguous stimuli. Participants perceived all four illusory motion percepts, and could not distinguish the illusion from the unambiguous stimuli. These results show that this illusion is effectively quadri-stable. In a second experiment, the illusory stimulus was looped continuously in headphones while participants identified its perceived path of motion to test properties of perceptual switching, locking, and biases. Participants were biased towards perceiving transverse compared to bouncing paths, and they became perceptually locked into alternating between front-to-back and back-to-front percepts, perhaps reflecting how auditory objects commonly move in the real world. This multi-stable auditory illusion opens opportunities for studying the perceptual, cognitive, and neural representation of objects in motion, as well as exploring multimodal perceptual awareness. PMID:25642180

  6. N400 to lexical ambiguity and semantic incongruity in schizophrenia.

    PubMed

    Salisbury, Dean

    2010-02-01

    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 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 that 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 displayed 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

  7. Chimpanzees and bonobos distinguish between risk and ambiguity

    PubMed Central

    Rosati, Alexandra G.; Hare, Brian

    2011-01-01

    Although recent research has investigated animal decision-making under risk, little is known about how animals choose under conditions of ambiguity when they lack information about the available alternatives. Many models of choice behaviour assume that ambiguity does not impact decision-makers, but studies of humans suggest that people tend to be more averse to choosing ambiguous options than risky options with known probabilities. To illuminate the evolutionary roots of human economic behaviour, we examined whether our closest living relatives, chimpanzees (Pan troglodytes) and bonobos (Pan paniscus), share this bias against ambiguity. Apes chose between a certain option that reliably provided an intermediately preferred food type, and a variable option that could vary in the probability that it provided a highly preferred food type. To examine the impact of ambiguity on ape decision-making, we interspersed trials in which chimpanzees and bonobos had no knowledge about the probabilities. Both species avoided the ambiguous option compared with their choices for a risky option, indicating that ambiguity aversion is shared by humans, bonobos and chimpanzees. PMID:21106573

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

    SciTech Connect

    Capri, M.A.L., E-mail: caprimarcio@gmail.com [Departamento de Fsica Terica, Instituto de Fsica, UERJ - Universidade do Estado do Rio de Janeiro, Rua So Francisco Xavier 524, 20550-013 Maracan, Rio de Janeiro (Brazil); Dudal, D., E-mail: david.dudal@ugent.be [Ghent University, Department of Physics and Astronomy, Krijgslaan 281-S9, 9000 Gent (Belgium); Guimaraes, M.S., E-mail: msguimaraes@uerj.br [Departamento de Fsica Terica, Instituto de Fsica, UERJ - Universidade do Estado do Rio de Janeiro, Rua So Francisco Xavier 524, 20550-013 Maracan, Rio de Janeiro (Brazil); Justo, I.F., E-mail: igorfjusto@gmail.com [Departamento de Fsica Terica, Instituto de Fsica, UERJ - Universidade do Estado do Rio de Janeiro, Rua So Francisco Xavier 524, 20550-013 Maracan, Rio de Janeiro (Brazil); Sorella, S.P., E-mail: sorella@uerj.br [Departamento de Fsica Terica, Instituto de Fsica, UERJ - Universidade do Estado do Rio de Janeiro, Rua So Francisco Xavier 524, 20550-013 Maracan, Rio de Janeiro (Brazil); 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 YangMills theories, in particular in the low momentum regime where standard perturbation theory based on the FaddeevPopov approach fails. Recent results, derived from functional tools (DysonSchwinger equations or exact RG) or the effective GribovZwanziger 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 FaddeevPopov 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) gaugeHiggs 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 FradkinShenker 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.

  9. Ambiguity resolution for satellite Doppler positioning systems

    NASA Technical Reports Server (NTRS)

    Argentiero, P.; Marini, J.

    1979-01-01

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

  10. 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

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

    SciTech Connect

    Asorey, M.; Berredo-Peixoto, G. de; Shapiro, I. L. [Departamento de Fisica Teorica, Universidad de Zaragoza, 50009, Zaragoza (Spain); Departamento de Fisica - ICE, Universidade Federal de Juiz de Fora, Juiz de Fora, 36036-330, MG (Brazil)

    2006-12-15

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

  12. Ambiguities in the scattering tomography for central potentials.

    PubMed

    Hendi, Awatif; Henn, Julian; Leonhardt, Ulf

    2006-08-18

    Invisibility devices exploit ambiguities in the inverse scattering problem of light in media. Scattering also serves as an important general tool to infer information about the structure of matter. We elucidate the nature of scattering ambiguities that arise in central potentials. We show that scattering is a tomographic projection: The integrated scattering angle is a projection of a scattering function onto the impact parameter. This function depends on the potential but may be multivalued, allowing for ambiguities where several potentials share the same scattering data. In addition, multivalued scattering angles also lead to ambiguities. We apply our theory to show that it is, in principle, possible to construct an invisibility device without infinite phase velocity of light. PMID:17026228

  13. 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.

  14. Ambiguity's aftermath: how age differences in resolving lexical ambiguity affect subsequent comprehension.

    PubMed

    Lee, Chia-lin; Federmeier, Kara D

    2012-04-01

    When ambiguity resolution is difficult, younger adults recruit selection-related neural resources that older adults do not. To elucidate the nature of those resources and the consequences of their recruitment for subsequent comprehension, we embedded noun/verb homographs and matched unambiguous words in syntactically well-specified but semantically neutral sentences. Target words were followed by a prepositional phrase whose head noun was plausible for only one meaning of the homograph. Replicating past findings, younger but not older adults elicited sustained frontal negativity to homographs compared to unambiguous words. On the subsequent head nouns, younger adults showed plausibility effects in all conditions, attesting to successful meaning selection through suppression. In contrast, older adults showed smaller plausibility effects following ambiguous words and failed to show plausibility effects when the context picked out the homograph's non-dominant meaning (i.e., they did not suppress the contextually-irrelevant dominant meaning). Meaning suppression processes, reflected in the frontal negativity, thus become less available with age, with consequences for subsequent comprehension. PMID:22321956

  15. Ambiguity and Conflict in Israeli-Lebanese Relations

    Microsoft Academic Search

    Oren Barak

    2010-01-01

    : The article discusses Israel’s ambiguous policy towards Lebanon since the late 1960s and early 1970s and assesses its long-term impact on Israeli-Lebanese relations. Its main argument is twofold: first, Israel reacted to the gradual decline of Lebanon’s effective sovereignty in the Lebanese-Israeli border area in the late 1960s and early 1970s by adopting an ambiguous policy, which, while recognizing

  16. GNSS antenna array-aided CORS ambiguity resolution

    NASA Astrophysics Data System (ADS)

    Li, Bofeng; Teunissen, Peter J. G.

    2014-04-01

    Array-aided precise point positioning is a measurement concept that uses GNSS data, from multiple antennas in an array of known geometry, to realize improved GNSS parameter estimation proposed by Teunissen (IEEE Trans Signal Process 60:2870-2881, 2012). In this contribution, the benefits of array-aided CORS ambiguity resolution are explored. The mathematical model is formulated to show how the platform-array data can be reduced and how the variance matrix of the between-platform ambiguities can profit from the increased precision of the reduced platform data. The ambiguity resolution performance will be demonstrated for varying scenarios using simulation. We consider single-, dual- and triple-frequency scenarios of geometry-based and geometry-free models for different number of antennas and different standard deviations of the ionosphere-weighted constraints. The performances of both full and partial ambiguity resolution (PAR) are presented for these different scenarios. As the study shows, when full advantage is taken of the array antennas, both full and partial ambiguity resolution can be significantly improved, in some important cases even enabling instantaneous ambiguity resolution. PAR widelaning and its suboptimal character are hereby also illustrated.

  17. 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

  18. Distilling entanglement from random cascades with partial "which path" ambiguity E. A. Meirom, N. H. Lindner, Y. Berlatzky, E. Poem, N. Akopian, J. E. Avron, and D. Gershoni

    E-print Network

    Avron, Joseph

    energy scale in the problem--gives negligible entanglement of the two qubits. Fortunately, in this case of polarization 3­5 . Unfortunately, unless the cascade obeys restrictive symmetry conditions, the two-qubit stateDistilling entanglement from random cascades with partial "which path" ambiguity E. A. Meirom, N. H

  19. GP consortia: navigating ambiguity to produce greater public value?

    PubMed

    Holbeche, Linda

    2011-05-01

    The UK's NHS is about to be significantly remodelled according to a white paper published in July 2010 that outlines the devolution of commissioning responsibilities away from strategic health authorities and primary care trusts to consortia of GPs, which are to be established at local level. Details of how the new GP consortia will operate are as yet unclear, but in essence they will be strategic alliances and it is likely that they will develop more or less formal arrangements between consortia partners, such as those of a commercial joint venture. This article draws on primary research into strategic alliances between organizations in all sectors. It suggests that there can be significant challenges for those working within strategic alliances, given that these tend to be beset by ambiguity and political tensions. In a context of ever greater transparency and accountability, it will be crucial to attend to the human aspects of strategic alliances since these represent significant risk if neglected. Conversely, alliances also offer the opportunity to develop the synergy of people, organizations and communities to deliver greater public value. Successful collaborations need to get three things right: governance, operations and behaviours. Relationships between consortia partners have a significant bearing on their ability to deliver desired outcomes. They must be able to build and maintain trust. Consortia partners will need sophisticated negotiating and stakeholder management skills and must be able to engage the public in setting the strategic goals for which they will be accountable. They also need strategic and operational management skills and must be able to cope with ambiguity and manage complexity. This paper argues that specific forms of leadership are needed in collaborative arrangements to mobilize people for positive action. People must work together by willingly and effectively pooling their initiative and expertise, and create a product or energy that is greater than the sum of their parts. The nature of leadership required to produce such high performance outcomes is likely to supersede leadership that is the result of structural relationships or of individual action. In particular, distributed leadership is likely to be relevant. PMID:21692401

  20. A negativity bias for ambiguous facial-expression valence during childhood: converging evidence from behavior and facial corrugator muscle responses.

    PubMed

    Tottenham, Nim; Phuong, Jessica; Flannery, Jessica; Gabard-Durnam, Laurel; Goff, Bonnie

    2013-02-01

    Interpretations of facial expressions with ambiguous valence, such as surprised (which can be perceived as having positive or negative valence), reveal individual differences in positivity-negativity biases. Negative interpretations are first and fast, but this initial negativity default can be overridden by regulatory control processes that result in positive interpretations. We tested the initial negativity hypothesis by examining positivity-negativity biases during development. We hypothesized that during childhood, the default negativity mode would be more evident than in adulthood and, as a group, children would show a negativity bias when processing ambiguous facial expressions. We examined ratings of two ambiguous expressions, surprised and neutral expressions, from childhood through adolescence and recorded facial corrugator muscle activity, a physiological index of negative appraisals. Surprised faces were rated as conveying clear negative affect by younger participants as indexed by fast RTs and negative ratings, and corrugator data showed a corresponding increase in activity to surprised faces. By adolescence, positive ratings of surprised faces became more frequent and RTs slowed, suggesting that surprised faces were perceived as having more ambiguous meaning. Accordingly, corrugator activity also decreased during adolescence. Neutral faces also produced negative ratings by children, but were also rated as conveying negative affect by older participants. Accordingly, neutral faces also elicited high corrugator activity that was similar to that elicited by negative expressions. These data show that early in life, ambiguous facial expressions are perceived as conveying negative meaning, adding support for an initial-negativity hypothesis. PMID:22906084

  1. 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 of the QPSK demodulator. The net effect of all the inversions would be that depending on which lock point the carrier-tracking loop had selected, all the output bits would be either inverted or non-inverted together; hence, the ambiguity would be reduced from fourfold to twofold, as desired.

  2. Some ambiguities of the student's role in undergraduate nurse training.

    PubMed

    Ashworth, P; Morrison, P

    1989-12-01

    Proposed changes in the way in which nurses are educated and trained will lead to stronger links between the academic and practical worlds of nursing. However, little or no attention has been focused on the potential difficulties associated with such a move for the student in this new and changing role. Important ambiguities of the student's role need to be addressed if the degree nursing student is to make the most of available opportunities for learning. In this paper we draw a distinction between two kinds of ambiguity in the role of nursing degree student during clinical placements. The first type is essential to the very nature of degree education in nursing, since the ambiguities here all entail problems in bridging the gap between the world of practical nursing and that of education. They include whether he or she is to regard the role as one of learner or producer of work; whether to become unreflectively acculturated to the organization or to reflect on its norms and values; and the student function within the organization. A second kind of ambiguity is not essential to nurse education, but is an unintended consequence of placement arrangements. The student is thrust into the clinical field as a short-term member of an organization; their position is anomalous and the motive for their involvement is largely different from that of permanent employees. These ambiguities of the role are also the source of important learning opportunities. PMID:2613953

  3. 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

  4. Assumptions and ambiguities in nonplanar acoustic soliton theory

    NASA Astrophysics Data System (ADS)

    Verheest, Frank; Hellberg, Manfred A.

    2014-02-01

    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.

  5. Descriptional Complexity of (Un)ambiguous Finite State Machines and Pushdown Automata

    NASA Astrophysics Data System (ADS)

    Holzer, Markus; Kutrib, Martin

    Unambiguity and its generalization to quantified ambiguity are important concepts in, e.g., automata and complexity theory. Basically, an unambiguous machine has at most one accepting computation path for each accepted word. While unambiguous pushdown automata induce a language family strictly in between the deterministic and general context-free languages, unambiguous finite automata capture the regular languages, that is, they are equally powerful as deterministic and nondeterministic finite automata. However, their descriptional capacity is significantly different. In the present paper, we summarize and discuss developments relevant to (un)ambiguous finite automata and pushdown automata problems from the descriptional complexity point of view. We do not prove these results but we merely draw attention to the big picture and some of the main ideas involved.

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

    PubMed Central

    Almeida, Aitor; Lpez-de-Ipia, 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

  7. 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.

  8. Domain-Specific Genetic Influence on Visual-Ambiguity Resolution.

    PubMed

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

    2014-06-01

    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

  9. EEG correlates of perceptual reversals in Boring's ambiguous old/young woman stimulus.

    PubMed

    Kornmeier, Jrgen; Bach, Michael

    2014-01-01

    Ambiguous figures attract observers because perception alternates between different interpretations while the sensory information stays unchanged. Understanding the underlying processes is difficult because the precise time instant of this endogenous reversal event needs to be known but is difficult to measure. Presenting ambiguous figures discontinuously and using stimulus onset as estimation of the reversal event increased temporal resolution and provided a series of well-confirmed EEG signatures. In the current EEG study we used this 'onset paradigm' for the first time with Boring's old/young woman stimulus. We found an early occipital event-related potential (ERP) correlate of reversals between the perception of the old woman and the perception of the young woman that fits well with previous ERP findings. This component was not followed by the often-reported occipito-parietal Reversal Negativity at 260 ms, but instead by an occipito-temporal N170, that is typically reported with face stimuli. We interpret our results as follows: ambiguity conflicts take place during processing of stimulus elements in early visual areas roughly 130 ms after stimulus onset. The disambiguation of these elements and their assembly to object 'gestalts' result from an interplay between early visual and object-specific brain areas in a temporal window between 130 and 260 ms after stimulus onset. In the particular case of Boring's old/young woman the processes of element disambiguation and gestalt construction are already finished at 170 ms and, thus, 90 ms earlier than in the case of ambiguous geometric figures (eg Necker cube or Schroeder staircase) or of binocular rivalrous gratings. PMID:25507318

  10. EEG correlates of perceptual reversals in Boring's ambiguous old/young woman stimulus.

    PubMed

    Kornmeier, Jrgen; Bach, Michael

    2014-01-01

    Ambiguous figures attract observers because perception alternates between different interpretations while the sensory information stays unchanged. Understanding the underlying processes is difficult because the precise time instant of this endogenous reversal event needs to be known but is difficult to measure. Presenting ambiguous figures discontinuously and using stimulus onset as estimation of the reversal event increased temporal resolution and provided a series of well-confirmed EEG signatures. In the current EEG study we used this 'onset paradigm' for the first time with Boring's old/young woman stimulus. We found an early occipital event-related potential (ERP) correlate of reversals between the perception of the old woman and the perception of the young woman that fits well with previous ERP findings. This component was not followed by the often-reported occipito-parietal Reversal Negativity at 260 ms, but instead by an occipito-temporal N170, that is typically reported with face stimuli. We interpret our results as follows: ambiguity conflicts take place during processing of stimulus elements in early visual areas roughly 130 ms after stimulus onset. The disambiguation of these elements and their assembly to object 'gestalts' result from an interplay between early visual and object-specific brain areas in a temporal window between 130 and 260 ms after stimulus onset. In the particular case of Boring's old/young woman the processes of element disambiguation and gestalt construction are already finished at 170 ms and, thus, 90 ms earlier than in the case of ambiguous geometric figures (eg Necker cube or Schroeder staircase) or of binocular rivalrous gratings. PMID:25420334

  11. 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.

  12. 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. PMID:23767923

  13. Molecular characterization of Mycobacterium avium complex isolates giving discordant results in AccuProbe tests by PCR-restriction enzyme analysis, 16S rRNA gene sequencing, and DT1-DT6 PCR.

    PubMed Central

    Devallois, A; Picardeau, M; Paramasivan, C N; Vincent, V; Rastogi, N

    1997-01-01

    Based on cultural and biochemical tests, a total of 84 strains (72 clinical and 12 environmental isolates from the Caribbean Isles, Europe, and the Indian subcontinent) were identified as members of the Mycobacterium avium complex (MAC). They were further characterized with MAC, M. avium, and M. intracellulare probes of the AccuProbe system, and this was followed by selective amplification of DT6 and DT1 sequences. Seventy isolates gave concordant results; 63 were identified as M. avium, 5 were identified as M. intracellulare, and 24 remained untypeable by both methods. Fourteen isolates gave discrepant results, as they were DT1 positive but gave negative results by the M. intracellulare AccuProbe test. Consequently, a detailed molecular analysis of all DT1-positive isolates (14 discrepant strains plus 5 M. intracellulare strains) was performed by PCR-restriction analysis (PRA) of the hsp65 gene and 16S rRNA gene sequencing. The results confirmed the reported heterogeneity of M. intracellulare, as only 6 of 19 isolates (32%) gave PRA results compatible with published M. intracellulare profiles while the rest of the isolates were grouped in four previously unpublished profiles. 16S rRNA gene sequencing showed that only 8 of 19 isolates (42%) were related to M. intracellulare IWGMT 90247 (EMBL accession no. X88917), the rest being related to MCRO19 (EMBL accession no. X93030) and MIWGTMR10 (EMBL accession no. X88915). In conclusion, we have characterized a significant number of MAC isolates which were not identified by the AccuProbe test, PRA, or 16S rRNA sequencing. However, all of them were identifiable by DT1-DT6 PCR (they were DT6 negative and DT1 positive) and could be tentatively identified as M. intracellulare based on previously published observations. It is noteworthy that the majority of such isolates (14 of 19) were from the Indian subcontinent, with 12 of 14 being environmental isolates. Our study confirms the marked heterogeneity of M. intracellulare isolates and shows the utility of in-house DT1 PCR to detect this group of isolates, which would otherwise have been missed by the AccuProbe system in a routine clinical microbiology laboratory. PMID:9350730

  14. Examining lateralized lexical ambiguity processing using dichotic and cross-modal tasks.

    PubMed

    Atchley, Ruth Ann; Grimshaw, Gina; Schuster, Jonathan; Gibson, Linzi

    2011-04-01

    The individual roles played by the cerebral hemispheres during the process of language comprehension have been extensively studied in tasks that require individuals to read text (for review see Jung-Beeman, 2005). However, it is not clear whether or not some aspects of the theorized laterality models of semantic comprehension are a result of the modality of presentation. Extending earlier work examining lateralized semantic processing using lexically ambiguous words, the current experiments utilized two modified lexical-decision tasks (one fully auditory and one cross-modal) with dichotically presented target stimuli. When targets were presented to the right ear/left hemisphere there was a distinct advantage for detecting words that are associated with the dominant meaning of the ambiguous word over the subordinate meaning. In contrast, for left ear/right hemisphere trials, there was either no difference between the pattern of semantic access for dominant and subordinate meaning (dichotic only) or a processing advantage for the subordinate meaning of the ambiguous word (with cross-modal presentation). These data suggest that the complimentary hemispheric strategies that allow for semantic access are not modality specific and instead characterize how the hemispheres each contribute to comprehension for both speech and text. Thus, dichotic presentation does seem to allow for the study of subtle hemispheric difference in meaning comprehension. PMID:21236275

  15. Algorithmic framework for X-ray nanocrystallographic reconstruction in the presence of the indexing ambiguity

    PubMed Central

    Donatelli, Jeffrey J.; Sethian, James A.

    2014-01-01

    X-ray nanocrystallography allows the structure of a macromolecule to be determined from a large ensemble of nanocrystals. However, several parameters, including crystal sizes, orientations, and incident photon flux densities, are initially unknown and images are highly corrupted with noise. Autoindexing techniques, commonly used in conventional crystallography, can determine orientations using Bragg peak patterns, but only up to crystal lattice symmetry. This limitation results in an ambiguity in the orientations, known as the indexing ambiguity, when the diffraction pattern displays less symmetry than the lattice and leads to data that appear twinned if left unresolved. Furthermore, missing phase information must be recovered to determine the imaged objects structure. We present an algorithmic framework to determine crystal size, incident photon flux density, and orientation in the presence of the indexing ambiguity. We show that phase information can be computed from nanocrystallographic diffraction using an iterative phasing algorithm, without extra experimental requirements, atomicity assumptions, or knowledge of similar structures required by current phasing methods. The feasibility of this approach is tested on simulated data with parameters and noise levels common in current experiments. PMID:24344317

  16. When language comprehension reflects production constraints: Resolving ambiguities with the help of past experience

    PubMed Central

    MacDonald, Maryellen C.; Thornton, Robert

    2014-01-01

    A key assumption in language comprehension is that biases in behavioral data, such as the tendency to interpret John said that Mary left yesterday to mean that yesterday modifies the syntactically local verb left, not the distant verb said, reflect inherent biases in the language comprehension system. In the present article, an alternative productiondistributioncomprehension (PDC) account is pursued; this account states that comprehension biases emerge from different interpretation frequencies in the language, which themselves emerge from pressures on the language production system to produce some structures more than others. In two corpus analyses and two self-paced reading experiments, we investigated these claims for verb modification ambiguities, for which phrase length is hypothesized to shape production. The results support claims that tendencies to produce short phrases before long ones create distributional regularities for modification ambiguities in the language and that learning over these regularities shapes comprehenders interpretations of modification ambiguities. Implications for the PDC and other accounts are discussed. PMID:19933460

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

    PubMed

    Ketteler, Simon; Ketteler, Daniel; Vohn, Ren; Kastrau, Frank; Schulz, Jrg 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

  18. 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:25538601

  19. Processing of the Reduced Relative Clause versus Main Verb Ambiguity in L2 Learners at Different Proficiency Levels

    ERIC Educational Resources Information Center

    Rah, Anne; Adone, Dany

    2010-01-01

    This article presents new evidence from offline and online processing of garden-path sentences that are ambiguous between reduced relative clause resolution and main verb resolution. The participants of this study are intermediate and advanced German learners of English who have learned the language in a nonimmersed context. The results show that

  20. Carrier phase ambiguity resolution for the Global Positioning System applied to geodetic baselines up to 2000 km

    Microsoft Academic Search

    Geoffrey Blewitt

    1989-01-01

    A technique for resolving the ambiguities in the GPS carrier phase data (which are biased by an integer number of cycles) is described which can be applied to geodetic baselines up to 2000 km in length and can be used with dual-frequency P code receivers. The results of such application demonstrated that a factor of 3 improvement in baseline accuracy

  1. Ambiguous Argument as Advocacy in Organizational Crisis Communication.

    ERIC Educational Resources Information Center

    Sellnow, Timothy L.; Ulmer, Robert R.

    1995-01-01

    Posits that organizations in crisis situations must address multiple audiences with distinct needs. Analyzes the public communication offered by Jack in the Box restaurants during a food poisoning outbreak. Finds that ambiguity may provide organizations with a means for satisfying the divergent needs of their audiences--even where these distinct

  2. Interpreting Ambiguous Advertisements: The Effect of Frontal Lobe Damage

    Microsoft Academic Search

    Samantha Pearce; Skye McDonald; Max Coltheart

    1998-01-01

    Despite intact primary language processes patients with frontal lobe deficits often have impaired communication skills including impaired capacity to understand conversational inference. This study examined the ability of three patients with demonstrated frontal lobe pathology to interpret lexically ambiguous advertisements. When compared to a nonbrain-damaged control group it was found that the frontal lobe patients were poorer at comprehending the

  3. Perceived Role Conflict, Role Ambiguity, and Teacher Burnout.

    ERIC Educational Resources Information Center

    Schwab, Richard L.; Iwanicki, Edward F.

    1982-01-01

    A questionnaire survey of a statewide sample of 469 Massachusetts teachers found that role conflict was significantly related to two aspects of teacher burnout, those of emotional exhaustion and negative attitudes toward students, and that role ambiguity was significantly connected to a third aspect, that of feelings of lack of personal

  4. Creativity and Tolerance of Ambiguity: An Empirical Study

    ERIC Educational Resources Information Center

    Zenasni, Franck; Besancon, Maud; Lubart, Todd

    2008-01-01

    This study examines the relationship between creativity and tolerance of ambiguity. Participants were parents and their adolescent children. Three measures of creativity were used: a divergent thinking task, a story-writing task and self-evaluation of creative attitudes and behavior. Participants completed two self-report measures of tolerance of

  5. Neural systems for word meaning modulated by semantic ambiguity

    Microsoft Academic Search

    Alice H. D. Chan; Ho-Ling Liu; Virginia Yip; Peter T. Fox; Jia-Hong Gao; Li Hai Tan

    2004-01-01

    One important issue in neuroimaging research on language is how the brain processes and represents lexical semantics. Past studies with various paradigms reveal that the left inferior prefrontal and mid-superior temporal regions play a crucial role in semantic processing. Those studies, however, typically utilize words having a precise and dominant meaning as stimuli and have not manipulated lexico-semantic ambiguity, a

  6. Ambiguity of -Languages of Turing Machines Olivier Finkel

    E-print Network

    Paris-Sud XI, Université de

    is the Centenary of Alan Turing's birth and that many scientific events will commemorate this year Turing's lifeAmbiguity of -Languages of Turing Machines Olivier Finkel Equipe de Logique Math´ematique Institut, i.e. the class of -languages accepted by Turing machines with a B¨uchi acceptance condition, which

  7. 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

  8. Some Pragmatic Features of Lexical Ambiguity and Simple Riddles.

    ERIC Educational Resources Information Center

    Weiner, E. Judith; DePalma, Paul

    1993-01-01

    Describes a category of riddles based on lexical ambiguity and uses category theory to illustrate the function of the accessibility hierarchy in riddling. A discussion of riddles and parallelism (the tendency to stay on the same syntactic, semantic, pragmatic track while processing language) shows how parallelism partially accounts for how the

  9. Developmental Aspects of the Ability to Understand Semantic Ambiguity.

    ERIC Educational Resources Information Center

    Brause, Rita S.

    The hypothesized ability of adult native speakers to understand linguistic ambiguity was tested. An approach developed to determine linguistic competence tested the ability of 90 participants in individual interviews to interpret sentences having the potential for multiple interpretations. The hypothesis was not supported by the data. A hierarchy

  10. Long-term priming of the meanings of ambiguous words

    ERIC Educational Resources Information Center

    Rodd, Jennifer M.; Lopez Cutrin, Belen; Kirsch, Hannah; Millar, Allesandra; Davis, Matthew H.

    2013-01-01

    Comprehension of semantically ambiguous words (e.g., "bark") is strongly influenced by the relative frequencies of their meanings, such that listeners are biased towards retrieving the most frequent meaning. These biases are often assumed to reflect a highly stable property of an individual's long-term lexical-semantic representations. We present

  11. 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

  12. 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,"

  13. 8. Morocco's political economy: Ambiguous privatization and the emerging social

    E-print Network

    Paris-Sud XI, Université de

    1 8. Morocco's political economy: Ambiguous privatization and the emerging social question Myriam at international level. In terms of political economy, alongside its historical and institutional specificities-documented analysis of the political economy of repression in Tunisia, the economic "good student". 2 Williamson 1990

  14. Accessing lexical ambiguity: Effects of context and dominance

    Microsoft Academic Search

    Patrizia Tabossi; Lucia Colombo; Remo Job

    1987-01-01

    The paper examines the effects of sentential context and frequency of meaning (dominance) on the lexical access of ambiguous words. Two experiments were carried out using Swinney's (1979) cross-modal paradigm. The sentential contexts were constructed in such a way as to make salient the most characteristic features of either the dominant (Experiment 1) or the secondary (Experiment 2) meaning of

  15. 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

  16. Utilization of Prosodic Information in Syntactic Ambiguity Resolution

    ERIC Educational Resources Information Center

    DeDe, Gayle

    2010-01-01

    Two self paced listening experiments examined the role of prosodic phrasing in syntactic ambiguity resolution. In Experiment 1, the stimuli consisted of early closure sentences (e.g., "While the parents watched, the child sang a song.") containing transitive-biased subordinate verbs paired with plausible direct objects or intransitive-biased

  17. 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

  18. 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.

  19. Reading-Time Studies of Second Language Ambiguity Resolution

    ERIC Educational Resources Information Center

    Papadopoulou, Despina

    2005-01-01

    This article provides a review of studies that have examined the ambiguity resolution strategies employed when processing a second language (L2). The way second language learners parse the L2 input has not yet been thoroughly investigated, although recently there has been an increasing interest in this area. The exploration of the mechanisms L2

  20. The Resolution of Syntactic Ambiguity in Automatic Language Processing

    ERIC Educational Resources Information Center

    Earl, Lois L.

    1972-01-01

    This paper describes how the problem of resolution of syntactic ambiguities is approached in the parser PHRASE, developed for use in experiments in automatic indexing and extracting. PHRASE is a multi-level parser for declarative sentences, in which the syntactic structure is built up in four stages. (10 references) (Author)

  1. Resolving and Mediating Ambiguous Contexts for Pervasive Care Environments

    E-print Network

    Julien, Christine

    ), context state (Si) and situation space (Ri), and attempts to incorporate various intuitions that should, a significant challenge facing the development of realistic and deployable context-aware services for healthcare applications is the ability to deal with ambiguous contexts to prevent hazardous situations. In this work, we

  2. A criterion for resolution of ambiguity of raster images

    Microsoft Academic Search

    W. Wojcik

    1996-01-01

    Although raster images are inherently ambiguous, humans exhibit uncanny abilities to come up with their likely interpretations. A methodology to simulate such behaviour on a computer is presented here. A numerical method for rejection of unlikely interpretations is given. A likely interpretation selected is found to depend on a particular raster pattern under study, but also on the architecture of

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

    ERIC Educational Resources Information Center

    Wankoff, Lorain Szabo; Cairns, Helen Smith

    2009-01-01

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

  4. RISK, AMBIGUITY, AND THE SAVAGE AXIOMS* By DANIELELLSBERG

    E-print Network

    Barrett, Jeffrey A.

    RISK, AMBIGUITY, AND THE SAVAGE AXIOMS* By DANIELELLSBERG I. Are there uncertaintiesthat are not risks?643. II. Uncertaintiesthat arenotrisks,647.- JII. Whyare some uncertaintiesnotrisks?- 656. I. ARE THERE UNCERTAINTIES THAT ARE NOT RISKS? There has always been a good deal of skepticismabout

  5. Violent Comic Books and Perceptions of Ambiguous Provocation Situations

    Microsoft Academic Search

    Steven J. Kirsh; Paul V. Olczak

    2000-01-01

    This study investigated the effects of reading very violent versus mildly violent comic books on the interpretation of ambiguous provocation situations, independent of trait hostility. 119 introductory psychology students read either a violent comic book, Curse of the Spawn, or a mildly violent comic book, Archie & Friends. After reading the comic books, participants read six shor t stories in

  6. Ideology, culture, and ambiguity: The revolutionary process in Iran

    Microsoft Academic Search

    Gene Burns

    1996-01-01

    To varying degrees, polysemous appeals are a feature of nearly all political coalitions and negotiations. But they are especially important in revolutions in which mass protests accompany a sudden collapse and elimination of the old regime state. In such a situation, it is not the case that a few coalition planks are ambiguous in an otherwise institution-alized political structure; instead,

  7. Medication error due to ambiguous labelling of a commercial product

    Microsoft Academic Search

    Henk-Jan Guchelaar; Mathijs D. Kalmeijer; Minke E. P. Jansen

    2004-01-01

    Medication errors may involve prescribing, dispensing, preparation and administration of drugs. We report a case in which an administration error occurred due to ambiguous labelling of a commercial drug. Tablets were packed in sets of two tablets per blister with the print on the blister 'Zelitrex 500', making the amount of drug per tablet unclear. A short survey among nurses

  8. Family Boundary Ambiguity, Marital Status, and Child Adjustment

    Microsoft Academic Search

    Cheryl Buehler; Kay Pasley

    2000-01-01

    The association between childrens perceptions of boundary ambiguity and their personal adjustment was examined in a sample of 262 children who lived with their biological parents and 87 children who lived with their single, divorced mothers or their divorced mothers and stepfathers. Adjustment was assessed by measuring mother and teacher reports of child problem behaviors and academic performance. The specific

  9. Investigation of Combined GPS/GALILEO Cascading Ambiguity Resolution Schemes

    E-print Network

    Calgary, University of

    Investigation of Combined GPS/GALILEO Cascading Ambiguity Resolution Schemes Wentao Zhang, M researches include GPS/GALILEO interoperability as well as GNSS receiver design. Paul Alves is a PhD student Engineering in May 2000. He has studied positioning and navigation with a focus on GPS and GALILEO integration

  10. Translation Ambiguity but Not Word Class Predicts Translation Performance

    ERIC Educational Resources Information Center

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

    2013-01-01

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

  11. 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

  12. Ballpoint probe gives optimum results in ultrasonic testing

    NASA Technical Reports Server (NTRS)

    Melton, R. E.

    1967-01-01

    Ballpoint-type ultrasonic probe assembly focuses its beam precisely on the bond lines of a composite thin face sheet structure when testing for bond integrity. It can scan in any direction, and eliminate external couplant spray.

  13. Do Market Incentives Crowd Out Charitable Giving?

    PubMed Central

    Deck, Cary; Kimbrough, Erik O.

    2013-01-01

    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. PMID:24348002

  14. Protection and internal transfer of technological competencies: The role of causal ambiguity

    Microsoft Academic Search

    Nuria Gonzlez-alvarez; Mariano Nieto-antoln

    2005-01-01

    Purpose The purpose of this paper is to study how causal ambiguity around technological competencies can help firms to achieve superior performance. Design\\/methodology\\/approach Traditionally, it has been recognised that causal ambiguity of technology represents an effective protection against imitation. Recently, however, researchers have unearthed evidence that the effects of causal ambiguity also could be extending to the interior

  15. Disjunctive ambiguity and the performance of Flannery O'connor's the displaced person

    Microsoft Academic Search

    Carole Ellsworth Tallant

    1986-01-01

    Narrative ambiguity, a concept which has only recently achieved prominence in literary criticism, has important implications for the performance of literature. This essay explores disjunctive narrative ambiguity and how it differs from other, similar literary devices. Specifically, this essay suggests group and solo performance techniques that can preserve and, in many cases, feature the disjunctive ambiguity in Flanner O'Connor's The

  16. Measures of Ambiguity of Computational Verbs Based on Computational Verb Collapses

    Microsoft Academic Search

    Tao Yang; Yi Guo

    2007-01-01

    The ambiguity of computational verbs is measured by using Shannon entropy. The ambiguities in the states and in the dynamics of computational verbs are studied based on the simplest computational verb collapses; namely, samples of the evolving functions of computational verbs at the ends of life spans. The ambiguities in the states of computational verbs can be either increased or

  17. hal-00080459,version2-13Dec2006 UNCERTAINTY PRINCIPLES FOR RADAR AMBIGUITY FUNCTIONS AND

    E-print Network

    Paris-Sud XI, Universit de

    hal-00080459,version2-13Dec2006 UNCERTAINTY PRINCIPLES FOR RADAR AMBIGUITY FUNCTIONS AND MOMENTS is not achievable because of the so-called "ambiguity uncertainty principle", that is the constraint R2 |A(u)(x, y are given by various versions of the uncertainty principle for the ambiguity function, see e.g. [BDJ, De, Gr

  18. Eye Movements and Lexical Ambiguity Resolution: Investigating the Subordinate-Bias Effect

    ERIC Educational Resources Information Center

    Sereno, Sara C.; O'Donnell, Patrick J.; Rayner, Keith

    2006-01-01

    Recent debates on lexical ambiguity resolution have centered on the subordinate-bias effect, in which reading time is longer on a biased ambiguous word in a subordinate-biasing context than on a control word. The nature of the control word--namely, whether it matched the frequency of the ambiguous word's overall word form or its contextually

  19. 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

  20. Boundary Ambiguity in Parents with Chronically Ill Children: Integrating Theory and Research

    ERIC Educational Resources Information Center

    Berge, Jerica M.; Holm, Kristen E.

    2007-01-01

    This article integrates theory and research related to boundary ambiguity in parents of children with a chronic health condition. We propose that boundary ambiguity is a risk factor for psychological distress in these parents. Clinical applications and a case example highlight how boundary ambiguity can be assessed and managed in clinical settings

  1. Punctuated equilibrium based on a locally ambiguous niche.

    PubMed

    Gunji, Yukio-Pegio; Sakiyama, Tomoko; Murakami, Hisashi

    2014-09-01

    Punctuated equilibrium, recently regarded as the power law distribution of lifespan, is estimated with respect to self-organized criticality. Previous explanations were based on a global property, such as the selection of species depending on their fitness, however a particular entity defined through such global property cannot be relevant to the notion of "self". Here, we introduce local ambiguity of a niche with respect to function and define a function network by using two types of maps. Due to the local complex structure of the function network, motif and lateral connections, some species are easily replaced by others, and other species have long lives. Punctuated equilibrium can, therefore, be explained by local ambiguous interaction, which suggests the notion of self and supports the idea of self-organized criticality. PMID:24905426

  2. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2014-12-01

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

  4. Fluorescence in situ hybridization as an ancillary tool in the diagnosis of ambiguous melanocytic neoplasms: a review of 804 cases.

    PubMed

    North, Jeffrey P; Garrido, Maria C; Kolaitis, Nicholas A; LeBoit, Philip E; McCalmont, Timothy H; Bastian, Boris C

    2014-06-01

    Previous studies have demonstrated the utility of fluorescence in situ hybridization (FISH) as an ancillary method in the diagnostic workup of histopathologically ambiguous melanocytic neoplasms. A combination of probes targeting 3 loci on chromosome 6 and 1 on 11q has been reported to distinguish unequivocal melanomas and nevi with a sensitivity and specificity of 87% and 96%, respectively. However, information on how FISH should be integrated into routine clinical testing is limited. We report our experience of FISH testing of 804 ambiguous melanocytic lesions performed as part of routine workup at University of California, San Francisco. The main category (47% of all cases) for which FISH testing was requested was Spitz tumors. Other categories included the distinction of possible melanoma from combined nevi (9%), acral or mucosal nevi (9%), Clark/dysplastic nevi (7%), and blue or deep penetrating nevi (6%) and to assess the possibility of nevoid melanoma (4%). Of the ambiguous tumors successfully tested, 88% received a more definitive benign or malignant final diagnosis. Of the 630 cases that tested negative by FISH, the final diagnosis was benign in 489 (78%) cases, ambiguous in 91 cases (14%), and malignant in 50 cases (8%). A positive FISH result was observed in 124 cases, with a final diagnosis of melanoma in 117 (94%). One (1%) FISH-positive case had an equivocal final diagnosis, and 6 (5%) were interpreted, despite the positive FISH result, as melanocytic nevi. We conclude that FISH testing can help reduce the number of equivocal diagnoses in ambiguous melanocytic neoplasms, in particular if FISH testing is positive, and discuss the challenges and limitations of FISH in clinical practice. PMID:24618603

  5. Infants' Use of Shared Linguistic Information to Clarify Ambiguous Requests

    ERIC Educational Resources Information Center

    Ganea, Patricia A.; Saylor, Megan M.

    2007-01-01

    Do infants use past linguistic information to interpret an ambiguous request for an object? When infants in this research were shown 2 objects, and asked for 1 with an indefinite request (e.g., "Can you get it for me?"), both 15- and 18-month-olds used the speaker's previous reference to an absent object to interpret the request. The 18-month-olds

  6. Polyaromatic hydrocarbon exposure: an ecological impact ambiguity.

    PubMed

    Ball, Andrew; Truskewycz, Adam

    2013-07-01

    Polyaromatic hydrocarbons (PAHs) represent a fraction of petroleum hydrocarbons and are currently one of the foremost sources of generating energy in today's contemporary society. However, evidence highlighted in this review show that PAH pollution, as a result of oil spills, hazardous PAH-contaminated working environments and technologies which do not efficiently utilise fuels, as well as natural sources of emissions (e.g. forest fires) may have significant health implications for all taxa. The extent of damage to organisms from PAH exposure is dependent on numerous factors including degree and type of PAH exposure, nature of the environment contaminated (i.e. terrestrial or aquatic), the ability of an organism to relocate to pristine environments, type and sensitivity of organism to specific hydrocarbon fractions and ability of the organism to metabolise different PAH fractions. The review highlights the fact that studies on the potential damage of PAHs should be carried out using mixtures of hydrocarbons as opposed to individual hydrocarbon fractions due to the scarcity of individual fractions being a sole contaminant. Furthermore, potential damage of PAH-contaminated sites should be assessed using an entire ecological impact outlook of the affected area. PMID:23529398

  7. 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.

  8. Children's use of language context in lexical ambiguity resolution.

    PubMed

    Khanna, Maya M; Boland, Julie E

    2010-01-01

    Lexical ambiguity resolution was examined in children aged 7 to 10 years and adults. In Experiment 1, participants heard sentences supporting one (or neither) meaning of a balanced ambiguous word in a cross-modal naming paradigm. Naming latencies for context-congruent versus context-incongruent targets and judgements of the relatedness of targets to the sentence served as indices of appropriate context use. While younger children were faster to respond to related targets regardless of the sentence context, older children and adults showed priming only for context-appropriate targets. In Experiment 2, only a single-word context preceded the homophone, and in contrast to Experiment 1, all groups showed contextual sensitivity. Individual working-memory span and inhibition ability were also measured in Experiment 2, and more mature executive function abilities were associated with greater contextual sensitivity. These findings support a developmental model whereby sentential context use for lexical ambiguity resolution increases with age, cognitive processing capacity, and reading skill. PMID:19424907

  9. Right semantic modulation of early MEG components during ambiguity resolution.

    PubMed

    Harpaz, Yuval; Lavidor, Michal; Goldstein, Abraham

    2013-11-15

    The time-line of lexical ambiguity resolution in bilateral neuronal networks was investigated using magnetoencephalography (MEG) in a semantic decision task. Dominant and subordinate associations of ambiguous words are considered to be processed in the left and right hemispheres, respectively. In the experiment, ambiguous words were followed by dominant or subordinate associations (manipulated between blocks) or by unrelated target words, and participants (N=25) decided whether the words in each pair were related or not. Subordinate meaning blocks elicited greater changes in the magnetic fields relative to dominant ones over the right, but not the left hemisphere (LH) at 150-235 ms from target onset, a time window corresponding to the M/N170 M/EEG component. Beamforming analysis localized the differential right hemisphere (RH) activity at the perisylvian area, including the homologue regions of Broca's and Wernicke's. At a later stage (235-390 ms) there was no significant difference between the two meaning conditions. We suggest that the RH language regions assist the LH in integrating subordinate disambiguating clues to preceding context during the M170 time window. PMID:23707585

  10. Assessment of Ambiguous Base Calls in HIV-1 pol Population Sequences as a Biomarker for Identification of Recent Infections in HIV-1 Incidence Studies

    PubMed Central

    Hauser, Andrea; Jansen, Klaus; Yousef, Kaveh Pouran; Fiedler, Stefan; von Kleist, Max; Norley, Stephen; Somogyi, Sybille; Hamouda, Osamah; Bannert, Norbert; Bartmeyer, Barbara; Kcherer, Claudia

    2014-01-01

    An increase in the proportion of ambiguous base calls in HIV-1 pol population sequences during the course of infection has been demonstrated in different study populations, and sequence ambiguity thresholds to classify infections as recent or nonrecent have been suggested. The aim of our study was to evaluate sequence ambiguities as a candidate biomarker for use in an HIV-1 incidence assay using samples from antiretroviral treatment-naive seroconverters with known durations of infection (German HIV-1 Seroconverter Study). We used 2,203 HIV-1 pol population sequences derived from 1,334 seroconverters to assess the sequence ambiguity method (SAM). We then compared the serological incidence BED capture enzyme immunoassay (BED-CEIA) with the SAM for a subset of 723 samples from 495 seroconverters and evaluated a multianalyte algorithm that includes BED-CEIA results, SAM results, viral loads, and CD4 cell counts for 453 samples from 325 seroconverters. We observed a significant increase in the proportion of sequence ambiguities with the duration of infection. A sequence ambiguity threshold of 0.5% best identified recent infections with 76.7% accuracy. The mean duration of recency was determined to be 208 (95% confidence interval, 196 to 221) days. In the subset analysis, BED-CEIA achieved a significantly higher accuracy than the SAM (84.6 versus 75.5%, P < 0.001) and results were concordant for 64.2% (464/723) of the samples. Also, the multianalyte algorithm did not show better accuracy than the BED-CEIA (83.4 versus 84.3%, P = 0.786). In conclusion, the SAM and the multianalyte algorithm including SAM were inferior to the BED-CEIA, and the proportion of sequence ambiguities is therefore not a preferable biomarker for HIV-1 incidence testing. PMID:24920768

  11. NATIONAL CENTRAL UNIVERSITY FUND AT GIVE2ASIA HOW TO GIVE

    E-print Network

    NATIONAL CENTRAL UNIVERSITY FUND AT GIVE2ASIA HOW TO GIVE 340 Pine Street that serves as a catalyst for philanthropic investment in Asia. Give2Asia makes for the National Central University Fund are tax deductible. Give2Asia is recognized

  12. 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.

  13. 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

  14. Giving leads to happiness in young children.

    PubMed

    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

  15. Superconductivity: the Gift that Keeps on Giving

    E-print Network

    Goldberg, Bennett

    Superconductivity: the Gift that Keeps on Giving Superconductivity, first discovered recently the discovery of high superconducting transition temperatures in the ceramic copper oxides has superconductors. In the underdoped or pseudogap phase of the cuprate superconductors, a significant portion

  16. Berea College Honor Roll of Giving

    E-print Network

    Baltisberger, Jay H.

    and Matching Gis 82 #12;Honor Roll of Giving 4 CONTENTS John G. Fee Society 2012-2013 John G. Fee Society Foundation Lilly Endowment, Inc. Andrew W. Mellon Foundation Kay Moore William T. Moore, Jr., '45 Anne Ray

  17. 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.

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

    PubMed Central

    Yiltiz, Hrmetjan; 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

  19. 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 formerly present in maps of historic ecosystems for the region and can be applied to PLS datasets elsewhere, as well as other sources of ambiguous historical data. Mapping the newly classified data with ecological land units provides additional information on the distribution, abundance, and associations of tree species, as well as their relationships to environmental gradients before the industrial period, and clarifies the identities of species formerly mapped only to genus. We offer some caveats on the appropriate use of data derived in this way, as well as describing their potential.

  20. Simulating bistable perception with interrupted ambiguous stimulus using self-oscillator dynamics with percept choice bifurcation.

    PubMed

    Frstenau, Norbert

    2014-11-01

    A behavioral stochastic self-oscillator model is used for simulating interrupted ambiguous stimulus-induced percept reversals. The results provide further support for a dynamical systems foundation of cognitive and psychological problems as discussed in detail within the context of Gestalt psychology by Wagemans et al. (Concept Theor Found Psychol Bull 138(6):1218-1252, 2012), and for coordination dynamics of the brain (Kelso in Philos Trans R Soc B 367:906-918, 2012). Statistical evaluation of simulated reversal time series predicts a maximum of the percept reversal rate that conforms with a number of results in the literature. The macroscopic model is based on two inhibitorily coupled sets of three coupled nonlinear equations, one triplet for each percept. The derivation of our specific dynamics equations is based on a drastically simplified field theoretical approach using well-known phase synchronization for explaining brain dynamics on the macroscopic EEG level. The degree of coherence (contrast ?, 0???1) of the superimposed fields required for onset of bistable dynamics is related to a phase synchronization index of EEG fields, and it is used in the present context as ambiguity control parameter. For quantitative agreement with the experimental data, the addition of a stochastic Langevin force term in the attention equation proved essential. Formal analysis leads to a quantification of well-known "cognitive inertia" and supports the interplay between percept choice (bifurcation) dynamics during stimulus onset and adaptive gain (attention fatigue) driven quasiperiodic percept reversals. PMID:25181991

  1. 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. PMID:22581420

  2. Improving combinatorial ambiguities of tt events using neural networks

    NASA Astrophysics Data System (ADS)

    Shim, Ji Hyun; Lee, Hyun Su

    2014-06-01

    We present a method for resolving the combinatorial issues in the tt lepton+jets events occurring at the Tevatron collider. By incorporating multiple information into an artificial neural network, we introduce a novel event reconstruction method for such events. We find that this method significantly reduces the number of combinatorial ambiguities. Compared to the classical reconstruction method, our method provides significantly higher purity with the same efficiency. We illustrate the reconstructed observables for the realistic top-quark mass and the forward-backward asymmetry measurements. A Monte Carlo study shows that our method provides meaningful improvements in the top-quark measurements using the same amount of data as other methods.

  3. Overcoming ambiguities in classical and quantum correlation measures

    NASA Astrophysics Data System (ADS)

    Paula, F. M.; Saguia, A.; de Oliveira, Thiago R.; Sarandy, M. S.

    2014-10-01

    We identify ambiguities in the available frameworks for defining quantum, classical, and total correlations as measured by discord-like quantifiers. More specifically, we determine situations for which either classical or quantum correlations are not uniquely defined due to degeneracies arising from the optimization procedure over the state space. In order to remove such degeneracies, we introduce a general approach where correlations are independently defined, escaping therefore from a degenerate subspace. As an illustration, we analyze the trace-norm geometric quantum discord for two-qubit Bell-diagonal states.

  4. 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.

  5. 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. PMID:19507448

  6. Long-term Follow-up after Feminizing Genital Reconstruction in Patients with Ambiguous Genitalia and High Vaginal Confluence

    PubMed Central

    Park, Sungchan; Ha, Seong Heon

    2011-01-01

    We evaluated the long-term results of feminizing genital reconstruction in patients with genital ambiguity with high vaginal confluence. The medical records of 10 consecutive patients with ambiguous genitalia and high vaginal confluence who underwent feminizing genital reconstruction from 1996 to 2007 were reviewed. Seven patients had congenital adrenal hyperplasia, one had mixed gonadal dysgenesis, one had partial androgen insensitivity, and one had 5-alpha reductase deficiency syndrome. Median age at operation was 21 months (range, 2-47 months). Median follow up was 7.7 yr. Of the six patients who underwent feminizing genital reconstruction with the Gonzalez method, three had good results. Of the other three patients, one had a urethrovaginal fistula and underwent fistula repair 9 yr after, one had distal vaginal stenosis and underwent revision vaginoplasty 9 yr after, and one had a urethrovaginal fistula and urethral stricture. The patient with urogenital mobilization had persistent urogenital sinus. Feminizing genitoplasty using the Gonzalez method showed good long-term results in patients with ambiguous genitalia and Congenital adrenal hyperplasia. The procedure is less invasive than other approaches and results in excellent cosmetic outcomes; and complications can be corrected by relatively simple procedures. PMID:21394309

  7. Give.org Charity Reports Index

    NSDL National Science Digital Library

    A useful service available on the web from the Better Business Bureaus Wise Giving Alliance. The service "promotes ethical standards within the charitable community, provides information to the public on charitable organizations, and educates individual and corporate donors on wise giving." Give.org issues reports on non-profit organizations based on the number of inquiries received for an organization. They are available at this website or through the mail (see website for address). An index to the current reports is arranged alphabetically for easy browsing. Included with most reports is information on an organization's "background, current programs, governing body, fund-raising practices, tax-exempt status, finances, and indication of whether or not the organization complies with the 23 voluntary BBB Standards for Charitable Solicitations."

  8. Semantic Similarity in a Taxonomy: An Information-Based Measure and its Application to Problems of Ambiguity in Natural Language

    E-print Network

    Resnik, P

    2011-01-01

    This article presents a measure of semantic similarity in an IS-A taxonomy based on the notion of shared information content. Experimental evaluation against a benchmark set of human similarity judgments demonstrates that the measure performs better than the traditional edge-counting approach. The article presents algorithms that take advantage of taxonomic similarity in resolving syntactic and semantic ambiguity, along with experimental results demonstrating their effectiveness.

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

    NASA Astrophysics Data System (ADS)

    Butkiewicz, M.; Kwiatkowski, T.; Bartczak, P.; Dudzi?ski, 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 conclusions are: (1) the 4th harmonic dominates about 1 percent of lightcurves only at low amplitudes (A<0.1 mag, ? < 40). (2) The dominance of the 3rd harmonic can be observed more often only in the case of near-Earth asteroids, observed at ? > 30; for the main-belt asteroids (MBAs), it can be present only in small amplitude lightcurves (A < 0.1 mag). (3) The 1st harmonic is present quite often in the low-amplitude (A < 0.2 mag) lightcurves of MBAs; for NEAs it can be seen even in high-amplitude lightcurves (A<0.7~mag for ?? 40, A<0.9~mag for ? ? 50). (4) In 100 percent of the cases, the 2nd harmonic dominates the lightcurves of MBAs whose amplitudes A > 0.2 mag.

  10. Concealment of Give-Away Parts

    NSDL National Science Digital Library

    David Ipsen

    2008-04-01

    The outline of an animal is not the only feature that might give it away. Often some part of it, perhaps its eyes or its legs or its tail, might also be a clue. In this activity, these parts are called giveaway parts . The function of the first activity is to consider the problem of eye concealment more carefully as students investigate the usefulness of an eye stripe. In the second activity, the frog's give-away parts will be inspected through a series of exercises.

  11. Mental images can be ambiguous: reconstruals and reference-frame reversals.

    PubMed

    Peterson, M A; Kihlstrom, J F; Rose, P M; Glisky, M L

    1992-03-01

    Philosophers and psychologists have debated whether or not mental images of ambiguous figures are reversible as pictures of such figures are. Previously, empirical evidence both pro (Finke, Pinker, & Farah, 1989) and con (Chambers & Reisberg, 1985) has been obtained. In a series of four experiments, we identify the conditions under which images of classic ambiguous figures like the duck/rabbit and the snail/elephant are reversible. We distinguish between two types of reversal: those that entail a change in reference-frame specification as well as a reconstrual of image components (reference-frame realignments) and those that entail reconstruals only (reconstruals). We show that reference-frame realignments can occur in imagery, particularly if observers are given an explicit or an implicit suggestion; and that reconstruals of images occur commonly, regardless of experimental conditions. In addition, we show that images constructed from good parts are more likely to reverse than images constructed from poor parts. On the basis of these results, we propose a functional organization of shape memory that is consistent with shape recognition findings as well as with our reversal findings. PMID:1565009

  12. Event-related potentials indicate context effect in reading ambiguous words.

    PubMed

    Kotchoubey, Boris; El-Khoury, Sylvain

    2014-10-29

    The aim of the study was a comparison of lexical and contextual factors in understanding ambiguous words in German. First, a sample of native speakers selected 56 words having maximally strong differences between a dominant and a subordinate meaning. After this, another sample from the same population was visually presented with sentences that activated dominant or subordinate meanings of the words and were accompanied by probes associated with dominant or subordinate meanings. This resulted in a crossed design with two factors: sentence dominant vs. sentence subordinate and probe dominant vs. probe subordinate. An analysis of event-related brain potentials revealed a large, long-lasting and highly-significant N400 wave whenever the meaning of the probe was incongruent with the meaning of the sentence and the lack of this wave whenever the two meanings were congruent. In the typical N400 space and time, the effect was independent of whether the lexical word meaning was dominant or subordinate. At other sites and times, however (e.g., at lateral frontal electrodes F7/F8, and after 700ms), the congruence effect was significant after dominant sentences only. The data indicate that lexical factors have a rather limited influence on the activation of a particular meaning of ambiguous words. A strong context can virtually override even a very strong difference in the preference for different meanings. PMID:25463139

  13. A new ambiguity acceptance test threshold determination method with controllable failure rate

    NASA Astrophysics Data System (ADS)

    Wang, Lei; Verhagen, Sandra

    2015-04-01

    The ambiguity acceptance test is an important quality control procedure in high precision GNSS data processing. Although the ambiguity acceptance test methods have been extensively investigated, its threshold determine method is still not well understood. Currently, the threshold is determined with the empirical approach or the fixed failure rate (FF-) approach. The empirical approach is simple but lacking in theoretical basis, while the FF-approach is theoretical rigorous but computationally demanding. Hence, the key of the threshold determination problem is how to efficiently determine the threshold in a reasonable way. In this study, a new threshold determination method named threshold function method is proposed to reduce the complexity of the FF-approach. The threshold function method simplifies the FF-approach by a modeling procedure and an approximation procedure. The modeling procedure uses a rational function model to describe the relationship between the FF-difference test threshold and the integer least-squares (ILS) success rate. The approximation procedure replaces the ILS success rate with the easy-to-calculate integer bootstrapping (IB) success rate. Corresponding modeling error and approximation error are analysed with simulation data to avoid nuisance biases and unrealistic stochastic model impact. The results indicate the proposed method can greatly simplify the FF-approach without introducing significant modeling error. The threshold function method makes the fixed failure rate threshold determination method feasible for real-time applications.

  14. 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.

  15. Array-based satellite phase bias sensing: theory and GPS/BeiDou/QZSS results

    NASA Astrophysics Data System (ADS)

    Khodabandeh, A.; Teunissen, P. J. G.

    2014-09-01

    Single-receiver integer ambiguity resolution (IAR) is a measurement concept that makes use of network-derived non-integer satellite phase biases (SPBs), among other corrections, to recover and resolve the integer ambiguities of the carrier-phase data of a single GNSS receiver. If it is realized, the very precise integer ambiguity-resolved carrier-phase data would then contribute to the estimation of the receivers position, thus making (near) real-time precise point positioning feasible. Proper definition and determination of the SPBs take a leading part in developing the idea of single-receiver IAR. In this contribution, the concept of array-based between-satellite single-differenced (SD) SPB determination is introduced, which is aimed to reduce the code-dominated precision of the SD-SPB corrections. The underlying model is realized by giving the role of the local reference network to an array of antennas, mounted on rigid platforms, that are separated by short distances so that the same ionospheric delay is assumed to be experienced by all the antennas. To that end, a closed-form expression of the array-aided SD-SPB corrections is presented, thereby proposing a simple strategy to compute the SD-SPBs. After resolving double-differenced ambiguities of the arrays data, the variance of the SD-SPB corrections is shown to be reduced by a factor equal to the number of antennas. This improvement in precision is also affirmed by numerical results of the three GNSSs GPS, BeiDou and QZSS. Experimental results demonstrate that the integer-recovered ambiguities converge to integers faster, upon increasing the number of antennas aiding the SD-SPB corrections.

  16. 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.

  17. 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

  18. 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

  19. 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 peoples level of commitment to healthism/risk culture and on their level of confidence in the health authorities and mainstream medicine.

  20. Range ambiguity resolution technique applying pulse-position modulation in time-of-flight scanning lidar applications

    NASA Astrophysics Data System (ADS)

    Rieger, Peter

    2014-06-01

    Time-of-flight (ToF) range measurements rely on the unambiguous association of each received echo signal to its causative emitted pulse signal. This definite association is difficult when measuring long ranges at a high repetition rate, resulting in ambiguous range measurements. While methods and algorithms exist to overcome this fundamental problem of ToF measurement techniques like radar these may not be directly applied to lidar without adaptations. Especially, in airborne laser scanning, up to now it was a requirement to strictly avoid range ambiguities during data acquisition. We present a new method for resolving range ambiguities fully automatically in scanning lidar, enabling measurements exceeding the maximum unambiguous measurement range by far. As a theoretical foundation of our approach, we introduce a specific model of the lidar transmission path (i.e., emitter-target-receiver) accounting for the time-variability of consecutive measurements. Based on this model, we discuss the influence of intentional variation of the intervals between pulse emissions on the intervals of successively received echoes and delineate an algorithm for automated, definitive association of pulse emissions and their resulting echoes. Simulation results indicate a probability of incorrect associations of <10-5, which we positively proved by applying this technique to real-world scan data.

  1. On Analysing Query Ambiguity for Query Refinement: The Librarian Agent Approach

    Microsoft Academic Search

    Nenad Stojanovic

    2003-01-01

    \\u000a In this paper, we present an approach for the disambiguation of ontology-based queries. The approach is based on measuring\\u000a the ambiguity of a query with respect to the users initial information need. We define several types of ambiguities concerning\\u000a the structure of the underlying ontology and the content of the information repository. For each of these ambiguities we define\\u000a a

  2. Ionospheric effects in uncalibrated phase delay estimation and ambiguity-fixed PPP based on raw observable model

    NASA Astrophysics Data System (ADS)

    Gu, Shengfeng; Shi, Chuang; Lou, Yidong; Liu, Jingnan

    2015-02-01

    Zero-difference (ZD) ambiguity resolution (AR) reveals the potential to further improve the performance of precise point positioning (PPP). Traditionally, PPP AR is achieved by Melbourne-Wbbena and ionosphere-free combinations in which the ionosphere effect are removed. To exploit the ionosphere characteristics, PPP AR with L1 and L2 raw observable has also been developed recently. In this study, we apply this new approach in uncalibrated phase delay (UPD) generation and ZD AR and compare it with the traditional model. The raw observable processing strategy treats each ionosphere delay as an unknown parameter. In this manner, both a priori ionosphere correction model and its spatio-temporal correlation can be employed as constraints to improve the ambiguity resolution. However, theoretical analysis indicates that for the wide-lane (WL) UPD retrieved from L1/L2 ambiguities to benefit from this raw observable approach, high precision ionosphere correction of better than 0.7 total electron content unit (TECU) is essential. This conclusion is then confirmed with over 1 year data collected at about 360 stations. Firstly, both global and regional ionosphere model were generated and evaluated, the results of which demonstrated that, for large-scale ionosphere modeling, only an accuracy of 3.9 TECU can be achieved on average for the vertical delays, and this accuracy can be improved to about 0.64 TECU when dense network is involved. Based on these ionosphere products, WL/narrow-lane (NL) UPDs are then extracted with the raw observable model. The NL ambiguity reveals a better stability and consistency compared to traditional approach. Nonetheless, the WL ambiguity can be hardly improved even constrained with the high spatio-temporal resolution ionospheric corrections. By applying both these approaches in PPP-RTK, it is interesting to find that the traditional model is more efficient in AR as evidenced by the shorter time to first fix, while the three-dimensional positioning accuracy of the RAW model outperforms the combination model by about 7.9 % . This reveals that, with the current ionosphere models, there is actually no optimal strategy for the dual-frequency ZD ambiguity resolution, and the combination approach and raw approach each has merits and demerits.

  3. Giving to Glasgow: the Scholarships Fund

    E-print Network

    Glasgow, University of

    Giving to Glasgow: the Scholarships Fund #12;#12;01 Your choice to make a gift creates more scholarships, which means: More opportunity Since 1451 we've been creating opportunities for the talented and dedicated. Creating new Talent Scholarships means that the people who have the ability to come here can do

  4. Parent Giving TheCentennialCampagin

    E-print Network

    passionate parents will play an important role in ensuring our success. #12;V2C: Vision for the Second provides an opportunity to build relationships with other parents and stay connected to Parent Giving TheCentennialCampagin RiceAnnualFund What Your Gift Supports Rice is a small

  5. Todd Baumann Gives a Thumbs Up

    USGS Multimedia Gallery

    USGS hydrologist Todd Baumann gives a thumbs up after setting the Acoustic Doppler Current Profiler (ADCP) aboard the Butta Bean during the 2011 Flood. USGS uses the ADCP to make streamflow measurements. The ADCP emits soundwaves through the water column, which rebound off particles in the water ...

  6. Linking and Giving Among Teenage Girls

    Microsoft Academic Search

    Jacob K. Goeree; Margaret A. McConnell; Tifiany Mitchell; Tracey Tromp; Leeat Yariv

    2007-01-01

    We combine data collected on friendship networks and individual characteristics with experimental observations from a sequence of dictator games run at an all-girls school in Pasadena, California. Our analysis provides two sets of insights. First, we flnd that dictator giving is primarily explained by social distance, deflned as the length of the shortest path connecting a dictator and recipient in

  7. 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. PMID:25154116

  8. 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.

  9. To watch, to see, and to differ: An event-related potential study of concreteness effects as a function of word class and lexical ambiguity

    PubMed Central

    Lee, Chia-lin; Federmeier, Kara D.

    2009-01-01

    Electrophysiological techniques were used to assess the generalizability of concreteness effects on word processing across word class (nouns and verbs) and different types of lexical ambiguity (syntactic only and combined syntactic/semantic). The results replicated prior work in showing an enhanced N400 response and a sustained frontal negativity to concrete as compared with abstract nouns. The effect of concreteness on the N400 generalized to all word class and ambiguity conditions, whereas the frontal effect was present for all word types except for the syntactically and semantically ambiguous items when these were used as verbs. The seemingly dissociable ERP effects of concreteness at frontal and central/posterior electrode sites revealed by these data suggest that concreteness may impact multiple aspects of neurocognitive processing. PMID:17659768

  10. Ambiguities and symmetry relations associated with fermionic tensor densities

    SciTech Connect

    Dallabona, G. [Instituto de Fisica Teorica, Rua Pamplona 145, 01405-900-Sao Paulo, SP (Brazil); Battistel, O. A. [Departamento de Fisica, Universidade Federal de Santa Maria, Caixa Postal 5093, 97119-900, Santa Maria, RS (Brazil)

    2004-09-15

    We consider the consistent evaluation of perturbative (divergent) Green functions associated with fermionic tensor densities and the derivation of symmetry relations for them. We show that, in spite of current algebra methods being not applicable, it is possible to derive symmetry properties analogous to the Ward identities of vector and axial-vector densities. The proposed method, which is applicable to any previously chosen order of perturbative calculation, gives the same results as those of current algebra when such a tool is applicable. By using a very general calculational strategy, concerning the manipulations and calculations involving divergent Feynman integrals, we evaluate the purely fermionic two-point functions containing tensor vertices and derive their symmetry properties. The present investigation is the first step in the study and characterization of possible anomalies involving fermionic tensor densities, particularly in purely fermionic three-point functions.

  11. Giving encouragement as a transformational leadership technique.

    PubMed

    Davidhizar, R; Shearer, R

    1997-03-01

    Giving encouragement is not generally stated as a high priority role of health care supervisors. Traditionally, technical skills and productivity on the job were aspects that received the supervisor's primary focus. However, there is a growing appreciation that encouragement is a transformational leadership technique that is related to productivity on the job and to quality work. Use of encouragement is a leadership technique that fits in today's people-oriented work climate. PMID:10165425

  12. Giving ourselves: the ethics of anatomical donation.

    PubMed

    Gunderman, Richard B

    2008-01-01

    In some European countries, such as Italy, medical education is threatened by a dearth of anatomical specimens. Such a shortage could spread to other nations, including the United States. This article addresses two ethical questions in body donation. Why might people choose to donate their bodies to education and science? What sorts of ethical appeals might anatomists, physicians, and other health professionals make to patients and family members for anatomical donation? Two models of giving, egoistic and liberal, merit close examination. PMID:19177414

  13. Giving Presentations in Middle Schools: Best Practices

    NSDL National Science Digital Library

    2014-03-11

    This resources identifies best practices for giving presentations or talks in middle school classrooms and was developed to help scientists and engineers who have been asked to visit a middle school classroom. It provides helpful suggestions before, during, and after the presentation, as well questions for the teacher (e.g., what content do you want me to cover, what have students already learned about this content?).

  14. Giving Presentations in Elementary Schools: Best Practices

    NSDL National Science Digital Library

    This resources identifies best practices for giving presentations or talks in elementary classrooms and was developed to help scientists and engineers who have been asked to visit an elementary classroom. It provides helpful suggestions before, during, and after the presentation, as well questions for the teacher (e.g., what content do you want me to cover, what have students already learned about this content?).

  15. Predicting atmospheric delays for rapid ambiguity resolution in precise point positioning

    NASA Astrophysics Data System (ADS)

    Li, Xingxing; Zhang, Xiaohong; Guo, Fei

    2014-09-01

    Integer ambiguity resolution in precise point positioning (PPP) can shorten the initialization and re-initialization time, and ambiguity-fixed PPP solutions are also more reliable and accurate than ambiguity-float PPP solutions. However, signal interruptions are unavoidable in practical applications, particularly while operating in urban areas. Such signal interruptions can cause discontinuity of carrier phase arc, which introduces new integer ambiguities. Usually it will take approximately 15 min of continuous tracking to a reasonable number of satellites to fix new integer ambiguities. In many applications, it is impractical for a PPP user to wait for such a long time for the re-initialization. In this paper, a method for rapid ambiguity fixing in PPP is developed to avoid such a long re-initialization time. Firstly, the atmospheric delays were estimated epoch by epoch from ambiguity-fixed PPP solutions before the data gap or cycle slip occurs. A random walk procedure is then applied to predict the atmospheric delays accurately over a short time span. The predicted atmospheric delays then can be used to correct the observations which suffer from signal interruptions. Finally, the new ambiguities can be fixed with a distinct WL-LX-L3 (here LX denotes either of L1, L2) cascade ambiguity resolution strategy. Comprehensive experiments have demonstrated that the proposed method and strategy can fix zero-difference integer ambiguities successfully with only a single-epoch observation immediately after a short data gap. This technique works even when all satellites are interrupted at the same time. The duration of data gap bridged by this technique could be possibly extended if a more precise atmospheric delay prediction is found or on-the-fly (OTF) technology is applied. Based on the proposed method, real-time PPP with integer ambiguity fixing becomes more feasible in practice.

  16. Dissociation of decision making under ambiguity and decision making under risk: a neurocognitive endophenotype candidate for obsessive-compulsive disorder.

    PubMed

    Zhang, Long; Dong, Yi; Ji, Yifu; Zhu, Chunyan; Yu, Fengqiong; Ma, Huijuan; Chen, Xingui; Wang, Kai

    2015-03-01

    Evidence in the literature suggests that executive dysfunction is regarded as an endophenotype candidate for obsessive-compulsive disorder (OCD). Decision making is an important domain of executive function. However, few studies that have investigated whether decision making is a potential endophenotype for OCD have produced inconsistent results. Differences in the findings across these studies may be attributed to several factors: different study materials, comorbidity, medication, etc. There are at least two types of decision making that differ mainly in the degree of uncertainty and how much useful information about consequences and their probabilities are provided to the decision maker: decision making under ambiguity and decision making under risk. The aim of the present study was to simultaneously examine decision making under ambiguity as assessed by the Iowa Gambling Task (IGT) and decision making under risk as measured by the Game of Dice Task (GDT) in OCD patients and their unaffected first-degree relative (UFDR) for the first time. The study analyzed 55 medication-nave, non-depressed OCD patient probands, 55 UFDRs of the OCD patients and 55 healthy matched comparison subjects (CS) without a family history of OCD with the IGT, the GDT and a neuropsychological test battery. While the OCD patients and the UFDRs performed worse than the CS on the IGT, they were unimpaired on the GDT. Our study supports the claim that decision making under ambiguity differs from decision making under risk and suggests that dissociation of decision making under ambiguity and decision making under risk may qualify to be a neurocognitive endophenotypes for OCD. PMID:25315855

  17. Impact of emotional context congruency on decision making under ambiguity.

    PubMed

    Ate, Ania; Borst, Grgoire; Moutier, Sylvain; Varescon, Isabelle; Brown, Ingi; Houd, Olivier; Cassotti, Mathieu

    2013-04-01

    In this study, we tested the somatic marker hypothesis (SMH) by using an adaptation of the Iowa Gambling Task (IGT) in which the emotional context associated with primary inducers was systematically manipulated. In this modified version of the IGT, a picture of either a happy face or a fearful face was presented after each feedback. Critically, the expression of the face was either congruent or incongruent with the feedback delivered. Analyses of participants' choices revealed that the congruency of the emotional context with the feedback affects performance on the IGT: The ability to choose advantageously increases when the emotional context is congruent with feedback (i.e., happy faces after rewards and fearful ones after punishments), whereas this ability is impaired with an incongruent emotional context (i.e., fearful faces after rewards and happy faces after punishments). These findings provide evidence that decision making under ambiguity is driven by emotion-related signals, as postulated by the SMH. PMID:23398587

  18. Occupational overuse syndrome: moral ambiguities of New Zealand health professionals.

    PubMed

    Jaye, Chrystal; Fitzgerald, Ruth

    2011-10-01

    In this article we examine the moral ambiguities expressed by New Zealand health professionals regarding their clients and patients who have occupational overuse syndrome (OOS). Workers with OOS were described as being hard working and dedicated, but also undisciplined in their work and personal lives. The goal of rehabilitation in such cases is a return to full work duties and to this end, health professionals represent the disciplinary and normalizing technologies of the neoliberal state which, in New Zealand, provides financial support and treatment for injured workers. According to the health professionals in this study, the disciplinary technologies exercised through rehabilitation require that clients and patients internalize key values associated with the rhetoric of healthism; primarily self-discipline, self-control, self-denial, and willpower. These underpin successful rehabilitation and ongoing management of OOS, and at the same time represent the central values of the neoliberal capitalist workplace. PMID:21490295

  19. Differential age effects on lexical ambiguity resolution mechanisms

    PubMed Central

    Lee, Chia-lin; Federmeier, Kara D.

    2010-01-01

    Multiple neurocognitive subsystems are involved in resolving lexical ambiguity under different circumstances. We examined how processing in these subsystems changes with normal aging by comparing ERP responses to homographs and unambiguous words completing congruent sentences (with both semantic and syntactic contextual information) or syntactic prose (syntactic information only). Like young adults in prior work, older adults elicited more negative N400s to homographs in congruent sentences, suggesting mismatch between the context and residual activation of the contextually-irrelevant sense. However, the frontal negativity seen in young adults to homographs in syntactically well-defined but semantically neutral contexts was absent in older adults as a group, suggesting decline in recruiting additional neural resources to aid difficult semantic selection. A subset of older adults with high verbal fluency maintained a young-like effect pattern. PMID:21175671

  20. Differential age effects on lexical ambiguity resolution mechanisms.

    PubMed

    Lee, Chia-Lin; Federmeier, Kara D

    2011-07-01

    Multiple neurocognitive subsystems are involved in resolving lexical ambiguity under different circumstances. We examined how processing in these subsystems changes with normal aging by comparing ERP responses to homographs and unambiguous words completing congruent sentences (with both semantic and syntactic contextual information) or syntactic prose (syntactic information only). Like young adults in prior work, older adults elicited more negative N400s to homographs in congruent sentences, suggesting mismatch between the context and residual activation of the contextually irrelevant sense. However, the frontal negativity seen in young adults to homographs in syntactically well-defined but semantically neutral contexts was absent in older adults as a group, suggesting a decline in recruiting additional neural resources to aid difficult semantic selection. A subset of older adults with high verbal fluency maintained a young-like effect pattern. PMID:21175671

  1. Fast Integer Ambiguity Resolution for GPS Attitude Determination

    NASA Technical Reports Server (NTRS)

    Lightsey, E. Glenn; Crassidis, John L.; Markley, F. Landis

    1999-01-01

    In this paper, a new algorithm for GPS (Global Positioning System) integer ambiguity resolution is shown. The algorithm first incorporates an instantaneous (static) integer search to significantly reduce the search space using a geometric inequality. Then a batch-type loss function is used to check the remaining integers in order to determine the optimal integer. This batch function represents the GPS sightline vectors in the body frame as the sum of two vectors, one depending on the phase measurements and the other on the unknown integers. The new algorithm has several advantages: it does not require an a-priori estimate of the vehicle's attitude; it provides an inherent integrity check using a covariance-type expression; and it can resolve the integers even when coplanar baselines exist. The performance of the new algorithm is tested on a dynamic hardware simulator.

  2. 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.

  3. Evaluation of Sequence Ambiguities of the HIV-1 pol gene as a Method to Identify Recent HIV-1 Infection in Transmitted Drug Resistance Surveys

    PubMed Central

    Andersson, Emmi; Shao, Wei; Bontell, Irene; Cham, Fatim; Cuong, Do Duy; Wondwossen, Amogne; Morris, Lynn; Hunt, Gillian; Snnerborg, Anders; Bertagnolio, Silvia; Maldarelli, Frank; Jordan, Michael R

    2014-01-01

    Identification of recent HIV infection within populations is a public health priority for accurate estimation of HIV incidence rates and transmitted drug resistance. Determining HIV incidence rates by prospective follow-up of HIV-uninfected individuals is challenging and serological assays have important limitations. HIV diversity within an infected host increases with duration of infection. In this analysis, we explore a simple bioinformatics approach to assess viral diversity by determining the percentage of ambiguous base calls in sequences derived from standard genotyping of HIV-1 protease and reverse transcriptase. Sequences from 691 recently infected (?1 year) and chronically infected (>1 year) individuals from Sweden, Vietnam and Ethiopia were analyzed for ambiguity. A significant difference (p <0.0001) in the proportion of ambiguous bases was observed between sequences from individuals with recent and chronic infection in both HIV-1 subtype B and non-B infection, consistent with previous studies. In our analysis, a cutoff of <0.47% ambiguous base calls identified recent infection with a sensitivity and specificity of 88.8% and 74.6% respectively. 1,728 protease and reverse transcriptase sequences from 36 surveys of transmitted HIV drug resistance performed following World Health Organization guidance were analyzed for ambiguity. The 0.47% ambiguity cutoff was applied and survey sequences were classified as likely derived from recently or chronically infected individuals. 71% of patients were classified as likely to have been infected within one year of genotyping but results varied considerably amongst surveys. This bioinformatics approach may provide supporting population-level information to identify recent infection but its application is limited by infection with more than one viral variant, decreasing viral diversity in advanced disease and technical aspects of population based sequencing. Standardization of sequencing techniques and base calling and the addition of other parameters such as CD4 cell count may address some of the technical limitations and increase the usefulness of the approach. PMID:23583545

  4. 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

  5. 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

  6. 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

  7. Aging and the Use of Context in Ambiguity Resolution: Complex Changes From Simple Slowing

    Microsoft Academic Search

    Karen Stevens Dagerman; Maryellen C. MacDonald; Michael W. Harm

    Older and younger adults' abilities to use context information rapidly during ambiguity resolution were investigated. In Experiments 1 and 2, younger and older adults heard ambiguous words (e.g., fires) in sentences where the preceding context supported either the less frequent or more frequent meaning of the word. Both age groups showed good context use in offline tasks, but only young

  8. 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

  9. Top-Down Influence in Young Children's Linguistic Ambiguity Resolution Hugh Rabagliati

    E-print Network

    Pylkkänen, Liina

    Top-Down Influence in Young Children's Linguistic Ambiguity Resolution Hugh Rabagliati New York 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

  10. 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,

  11. Ambiguous Loss and the Media Practices of Transnational Latina Teens: A Qualitative Study

    Microsoft Academic Search

    Lucila Vargas

    2008-01-01

    Drawing on ethnographic data from a study with 17 working-class, transnational Latina teens, I examine the media practices they perform to cope with ambiguous loss. According to Pauline Boss (1993, 1999, 2006), ambiguous loss refers to a distinct type of loss that defies closure, such as the feelings of the family of a missing person. My findings suggest that Latina

  12. 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

  13. Typical Ambiguity: Trying to Have Your Cake and Eat it too.

    E-print Network

    Feferman, Solomon

    Typical Ambiguity: Trying to Have Your Cake and Eat it too. Solomon Feferman Would ye both eat your cake and have your cake? John Heywood, Proverbs1 Abstract. Ambiguity is a property of syntactic of types in order to combine the assurance of its (apparent) consistency ("having the cake

  14. Ambiguity Advantage Revisited: Two Meanings Are Better than One when Accessing Chinese Nouns

    ERIC Educational Resources Information Center

    Lin, Chien-Jer Charles; Ahrens, Kathleen

    2010-01-01

    This paper revisits the effect of lexical ambiguity in word recognition, which has been controversial as previous research reported advantage, disadvantage, and null effects. We discuss factors that were not consistently treated in previous research (e.g., the level of lexical ambiguity investigated, parts of speech of the experimental stimuli,

  15. Meaning Selection and the Subcortex: Evidence of Reduced Lexical Ambiguity Repetition Effects Following Subcortical Lesions

    ERIC Educational Resources Information Center

    Copland, David A.

    2006-01-01

    Recent research indicates that individuals with nonthalamic subcortical (NS) lesions can experience difficulties processing lexical ambiguities in a variety of contexts. This study examined how prior processing of a lexical ambiguity influences subsequent meaning activation in 10 individuals with NS lesions and 10 matched healthy controls.

  16. Perception of Lexical and Structural Ambiguity by Junior and Senior High School Students.

    ERIC Educational Resources Information Center

    Jurgens, Jeanne Marie

    The three concerns of this study were: (1) the ability of students in grades seven, nine, and eleven to recognize ambiguity in sentences at the lexical, surface structural, and underlying structural levels; (2) the relative difficulty of perceiving ambiguity at each of these levels as determined by differential processing times; and (3) the

  17. 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

  18. 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

  19. Ambiguity Detection in Adolescents with Asperger Syndrome: Is Central Coherence or Theory of Mind Impaired?

    ERIC Educational Resources Information Center

    Le Sourn-Bissaoui, Sandrine; Caillies, Stephanie; Gierski, Fabien; Motte, Jacques

    2011-01-01

    The aim of this study was to investigate the role of central coherence skills and theory of mind competences in ambiguity detection in adolescents with Asperger syndrome (AS). We sought to pinpoint the level at which AS individuals experience difficulty detecting semantic ambiguity and identify the factors that account for their problems. We

  20. Role Ambiguity, Role Conflict and Job Satisfaction among Physical Education Teachers in Greece

    ERIC Educational Resources Information Center

    Koustelios, Athanasios; Theodorakis, Nicholas; Goulimaris, Dimitris

    2004-01-01

    This study examines role conflict, role ambiguity, and job satisfaction among Greek physical education teachers, and the extent to which role conflict and role ambiguity predict job satisfaction. All members of the sample of 61 physical education teachers were employed in Greek "Sport for all" programs. The standard multiple regression analysis

  1. 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

  2. An Eye-Movement Analysis of Ambiguity Resolution: Beyond Meaning Access

    ERIC Educational Resources Information Center

    Binder, Katherine S.; Morris, Robin K.

    2011-01-01

    The research reported here addresses the status of the unselected meaning of a lexically ambiguous word in developing the larger meaning of the text by independently manipulating lexical and discourse-level variables in the text. In a series of 3 eye-movement experiments, participants read passages that contained 2 occurrences of an ambiguous

  3. The Effect of Phonemic Repetition on Syntactic Ambiguity Resolution: Implications for Models of Working Memory

    ERIC Educational Resources Information Center

    Kennison, Shelia M.

    2004-01-01

    Two reading experiments investigated the extent to which the presence of phonemic repetition in sentences influenced processing difficulty during syntactic ambiguity resolution. In both experiments, participants read sentences silently as reading time was measured. Reading time on sentences containing a temporary syntactic ambiguity was compared

  4. Aging and the Use of Context in Ambiguity Resolution: Complex Changes from Simple Slowing

    ERIC Educational Resources Information Center

    Dagerman, Karen Stevens; MacDonald, Maryellen C.; Harm, Michael W.

    2006-01-01

    Older and younger adults' abilities to use context information rapidly during ambiguity resolution were investigated. In Experiments 1 and 2, younger and older adults heard ambiguous words (e.g., fires) in sentences where the preceding context supported either the less frequent or more frequent meaning of the word. Both age groups showed good

  5. The Time Course of Lexical Ambiguity Resolution in Context. Technical Report No. 164.

    ERIC Educational Resources Information Center

    Seidenberg, Mark S.; And Others

    Two experiments on the processing of lexical ambiguities in spoken prose were conducted using college students as subjects. The studies focused on noun-noun ambiguities, e.g. "straw" and "organ." The experiments utilized a variable stimulus onset asynchrony priming paradigm in which an auditory stimulus is followed at a variable interval (either 0

  6. 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

  7. The Descriptive and Predictive Adequacy of Theories of Decision Making Under Uncertainty\\/Ambiguity

    Microsoft Academic Search

    John D Hey; Gianna Lotito; Anna Maffioletti

    2008-01-01

    In this paper we examine the performance of theories of decision making under uncertainty\\/ambiguity from the perspective of their descriptive and predictive power, taking into account the relative parsimony of the various theories. To this end, we employ an innovative experimental design which enables us to reproduce ambiguity in the laboratory in a transparent and non-probabilistic way. We find that

  8. Exploiting Lexical Ambiguity to Help Students Understand the Meaning of "Random"

    ERIC Educational Resources Information Center

    Kaplan, Jennifer J.; Rogness, Neal T.; Fisher, Diane G.

    2014-01-01

    Words that are part of colloquial English but used differently in a technical domain may possess lexical ambiguity. The use of such words by instructors may inhibit student learning if incorrect connections are made by students between the technical and colloquial meanings. One fundamental word in statistics that has lexical ambiguity for students

  9. Family Boundary Ambiguity and the Measurement of Family Structure: The Significance of Cohabitation

    Microsoft Academic Search

    Susan L. Brown; Wendy D. Manning

    2009-01-01

    We used data from the first wave of the National Longitudinal Study of Adolescent Health to examine family boundary ambiguity in adolescent and mother reports of family structure and found that the greater the family complexity, the more likely adolescent and mother reports of family structure were discrepant. This boundary ambiguity in reporting was most pronounced for cohabiting stepfamilies. Among

  10. The Ambiguities of Out-of-Home Care: Children with Severe or Profound Disabilities

    ERIC Educational Resources Information Center

    Roper, Susanne Olsen; Jackson, Jeffrey B.

    2007-01-01

    Ambiguous loss and boundary ambiguity experienced by families during the process of placing their child in out-of-home care was described by parents in 20 families raising a child with severe or profound developmental disabilities. In retrospective interviews, parents discussed their experiences before and after placing their child and how they

  11. 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

  12. 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

  13. Chinese cultural values and gift-giving behavior

    Microsoft Academic Search

    Wang Qian; Mohammed Abdur Razzaque; Kau Ah Keng

    2007-01-01

    Purpose The purpose of this paper is to report the results of a study undertaken to investigate the gift-giving behavior of consumers in the People's Republic of China (PRC) during the Chinese New Year and the influence exerted by Chinese cultural values on such behavior. Design\\/methodology\\/approach Using a survey among a large sample of people in the city

  14. To Watch, to See, and to Differ: An Event-Related Potential Study of Concreteness Effects as a Function of Word Class and Lexical Ambiguity

    ERIC Educational Resources Information Center

    Lee, Chia-lin; Federmeier, Kara D.

    2008-01-01

    Electrophysiological techniques were used to assess the generalizability of concreteness effects on word processing across word class (nouns and verbs) and different types of lexical ambiguity (syntactic only and combined syntactic/semantic). The results replicated prior work in showing an enhanced N400 response and a sustained frontal negativity

  15. Processing Subject-Object Ambiguities in the L2: A Self-Paced Reading Study with German L2 Learners of Dutch

    ERIC Educational Resources Information Center

    Havik, Else; Roberts, Leah; van Hout, Roeland; Schreuder, Robert; Haverkort, Marco

    2009-01-01

    The results of two self-paced reading experiments are reported, which investigated the online processing of subject-object ambiguities in Dutch relative clause constructions like "Dat is de vrouw die de meisjes heeft/hebben gezien" by German advanced second language (L2) learners of Dutch. Native speakers of both Dutch and German have been shown

  16. An Ambiguous Statement Called 'Tetrad Postulate' and the Correct Field Equations Satisfied by the Tetrad Fields

    E-print Network

    Waldyr A. Rodrigues Jr.; Quintino A. Gomes de Souza

    2008-01-06

    The names tetrad, tetrads, cotetrads, have been used with many different meanings in the physical literature, not all of them, equivalent from the mathematical point of view. In this paper we introduce unambiguous definitions for each one of those terms, and show how the old miscellanea made many authors to introduce in their formalism an ambiguous statement called `tetrad postulate', which has been source of many misunderstandings, as we show explicitly examining examples found in the literature. Since formulating Einstein's field equations intrinsically in terms of cotetrad fields theta^{a}, a = 0,1,2,3 is an worth enterprise, we derive the equation of motion of each theta^{a} using modern mathematical tools (the Clifford bundle formalism and the theory of the square of the Dirac operator). Indeed, we identify (giving all details and theorems) from the square of the Dirac operator some noticeable mathematical objects, namely, the Ricci, Einstein, covariant D'Alembertian and the Hodge Laplacian operators, which permit to show that each theta^{a} satisfies a well defined wave equation. Also, we present for completeness a detailed derivation of the cotetrad wave equations from a variational principal. We compare the cotetrad wave equation satisfied by each theta^{a} with some others appearing in the literature, and which are unfortunately in error.

  17. 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.

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

    NASA Astrophysics Data System (ADS)

    Kohri, Kazunori; Matsuda, Tomohiro

    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 0Ne~ 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.

  19. Role conflict, role ambiguity, and burnout in nurses and physicians at a university hospital in Turkey.

    PubMed

    Tunc, Tulin; Kutanis, Rana Ozen

    2009-12-01

    In many countries currently, health-care professionals experience burnout in their professional life. This study explored the relationship between burnout, and role conflict and role ambiguity in nurses and physicians at a university hospital in Turkey. The data were collected by questionnaires that included sociodemographic variables, Maslach's Burnout Inventory (MBI), and Rizzo's Role Conflict and Role Ambiguity Scales. Two hundred and fifty one health-care professionals (170 physicians and 81 nurses) responded to the survey. There was a strong positive correlation between the MBI and Rizzo's Role Conflict and Role Ambiguity Scales. The nurses showed significantly higher levels of role conflict, role ambiguity, and burnout compared to the physicians. A multiple regression analysis showed that role conflict and role ambiguity might help to explain the higher level of burnout experienced by the nurses compared to the physicians. Future research is needed to develop preventive measures for the burnout of health-care professionals. PMID:19909450

  20. 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. PMID:25758706

  1. 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. PMID:18044276

  2. Identification of ambiguities in the 1994 chronic fatigue syndrome research case definition and recommendations for resolution

    PubMed Central

    Reeves, William C; Lloyd, Andrew; Vernon, Suzanne D; Klimas, Nancy; Jason, Leonard A; Bleijenberg, Gijs; Evengard, Birgitta; White, Peter D; Nisenbaum, Rosane; Unger, Elizabeth R

    2003-01-01

    Background Chronic fatigue syndrome (CFS) is defined by symptoms and disability, has no confirmatory physical signs or characteristic laboratory abnormalities, and the etiology and pathophysiology remain unknown. Difficulties with accurate case ascertainment contribute to this ignorance. Methods Experienced investigators from around the world who are involved in CFS research met for a series of three day workshops in 2000, 2001 and 2002 intended to identify the problems in application of the current CFS case definition. The investigators were divided into focus groups and each group was charged with a topic. The investigators in each focus group relied on their own clinical and scientific knowledge, brainstorming within each group and with all investigators when focus group summaries were presented. Relevant literature was selected and reviewed independent of the workshops. The relevant literature was circulated via list-serves and resolved as being relevant by group consensus. Focus group reports were analyzed and compiled into the recommendations presented here. Results Ambiguities in the current CFS research definition that contribute to inconsistent case identification were identified. Recommendations for use of the definition, standardization of classification instruments and study design issues are presented that are intended to improve the precision of case ascertainment. The International CFS Study Group also identified ambiguities associated with exclusionary and comorbid conditions and reviewed the standardized, internationally applicable instruments used to measure symptoms, fatigue intensity and associated disability. Conclusion This paper provides an approach to guide systematic, and hopefully reproducible, application of the current case definition, so that case ascertainment would be more uniform across sites. Ultimately, an operational CFS case definition will need to be based on empirical studies designed to delineate the possibly distinct biological pathways that result in chronic fatigue. PMID:14702202

  3. Rocking or Rolling Perception of Ambiguous Motion after Returning from Space

    PubMed Central

    Clment, 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 12 days. During dynamic linear acceleration (0.150.6 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 foreaft 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

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

    PubMed

    Clment, 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

  5. NFS gives Career Awards to Women

    NASA Astrophysics Data System (ADS)

    Five geophysicists are among 38 women who received a total of $1.64 million in Career Advancement Awards in November from the National Science Foundation through its Research Opportunities for Women (ROW) initiative. Individual awards are as large as $60,000 and give recipients opportunities to work with other investigators and develop new lines of research.Patricia M. Costanzo of the State University of New York (SUNY), Buffalo, is studying dehydrated kaolinites. At the University of Alaska's Institute of Geophysics, Joan P. Gosink is applying remote sensing to snow, ice and permafrost research. Mary Kraus of the University of Colorado, Boulder, is combining field studies and remote sensing to work out the depositional history of the Bighorn Basin in Wyoming. The research of Cecile Penland of the University of California, Los Angeles, is on variability in northern hemisphere geopotential heights. Judith B. Weinstein-Lloyd of SUNY College at Old Westbury is studying the chemistry of hydrogen peroxide in cloudwater.

  6. Reasonable Averages That Give Wrong Answers

    NSDL National Science Digital Library

    Shahani, A. K. (Arjan Kewalram)

    Averages are meant to convey the essential features of a set of data, or a random variable, in a simple and a concise way. Like any other summary, an average can be misleading, misused and abused; there is a fair amount of literature on this aspect of averages, the book by D. Huff(1973) being a particularly readable account. In one intuitive use of averages there is a source of error which can be quite serious and which is often not recognized. This source of error is illustrated below by a quality control problem, a project, an experiment and a game. A Taylor series expansion gives an insight into the nature of the error.

  7. Analysis of Genetic Code Ambiguity Arising from Nematode-Specific Misacylated tRNAs

    PubMed Central

    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-tRNAGly (CCC) and nev-tRNAIle (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

  8. Violation of contextual generalization of the LeggettGarg inequality for recognition of ambiguous figures

    NASA Astrophysics Data System (ADS)

    Asano, Masanari; Hashimoto, Takahisa; Khrennikov, Andrei; Ohya, Masanori; Tanaka, Yoshiharu

    2014-12-01

    We interpret the LeggettGarg (LG) inequality as a kind of contextual probabilistic inequality in which one combines data collected in experiments performed for three different contexts. In the original version of the inequality, these contexts have a temporal nature and they are represented by three pairs of instances of time, ({{t}1},{{t}2}),({{t}2},{{t}3}),({{t}3},{{t}4}), where {{t}1}\\lt {{t}2}\\lt {{t}3}. We generalize LG conditions of macroscopic realism and noninvasive measurability in a general contextual framework. Our formulation is performed in purely probabilistic terms: the existence of the context-independent joint probability distribution P and the possibility of reconstructing the experimentally found marginal (two-dimensional) probability distributions from P. We derive an analog of the LG inequality, contextual LG inequality, and use it as a test of quantum-likeness of statistical data collected in a series of experiments on the recognition of ambiguous figures. In our experimental study, the figure under recognition is the Schrder stair, which is shown with rotations for different angles. Contexts are encoded by dynamics of rotations: clockwise, anticlockwise and random. Our data demonstrated violation of the contextual LG inequality for some combinations of the aforementioned contexts. Since in quantum theory and experiments with quantum physical systems, this inequality is violated, e.g. in the form of the original LG-inequality, our result can be interpreted as a sign that the quantum-like models can provide a more adequate description of the data generated in the process of recognition of ambiguous figures.

  9. Visual motion integration is mediated by directional ambiguities in local motion signals.

    PubMed

    Rocchi, Francesca; Ledgeway, Tim; Webb, Ben S

    2013-01-01

    The output of primary visual cortex (V1) is a piecemeal representation of the visual scene and the response of any one cell cannot unambiguously guide sensorimotor behavior. It remains unsolved how subsequent stages of cortical processing combine ("pool") these early visual signals into a coherent representation. We (Webb et al., 2007, 2011) have shown that responses of human observers on a pooling task employing broadband, random dot motion can be accurately predicted by decoding the maximum likelihood direction from a population of motion-sensitive neurons. Whereas Amano et al. (2009) found that the vector average velocity of arrays of narrowband, two-dimensional (2-d) plaids predicts perceived global motion. To reconcile these different results, we designed two experiments in which we used 2-d noise textures moving behind spatially distributed apertures and measured the point of subjective equality between pairs of global noise textures. Textures in the standard stimulus moved rigidly in the same direction, whereas their directions in the comparison stimulus were sampled from a set of probability distributions. Human observers judged which noise texture had a more clockwise (CW) global direction. In agreement with Amano and colleagues, observers' perceived global motion coincided with the vector average stimulus direction. To test if directional ambiguities in local motion signals governed perceived global direction, we manipulated the fidelity of the texture motion within each aperture. A proportion of the apertures contained texture that underwent rigid translation and the remainder contained dynamic (temporally uncorrelated) noise to create locally ambiguous motion. Perceived global motion matched the vector average when the majority of apertures contained rigid motion, but with increasing levels of dynamic noise shifted toward the maximum likelihood direction. A class of population decoders utilizing power-law non-linearities can accommodate this flexible pooling. PMID:24302910

  10. Substrate ambiguous enzymes within the Escherichia coli proteome offer different evolutionary solutions to the same problem.

    PubMed

    Yip, Sylvia Hsu-Chen; Matsumura, Ichiro

    2013-09-01

    Many enzymes exhibit some catalytic promiscuity or substrate ambiguity. These weak activities do not affect the fitness of the organism under ordinary circumstances, but can serve as potential evolutionary precursors of new catalytic functions. We wondered whether different proteins with the same substrate ambiguous activity evolve differently under identical selection conditions. Patrick et al. (Patrick WM, Quandt EM, Swartzlander DB, Matsumura I. 2007. Multicopy suppression underpins metabolic evolvability. Mol Biol Evol. 24:2716-2722.) previously showed that three multicopy suppressors, gph, hisB, and ytjC, rescue ?serB Escherichia coli cells from starvation on minimal media. We directed the evolution of variants of Gph, histidinol phosphatase (HisB), and YtjC that complemented ?serB more efficiently, and characterized the effects of the amino acid changes, alone and in combination, upon the evolved phosphoserine phosphatase (PSP) activity. Gph and HisB are members of the HAD superfamily of hydrolases, but they adapted through different, kinetically distinguishable, biochemical mechanisms. All of the selected mutations, except N102T in YtjC, proved to be beneficial in isolation. They exhibited a pattern of antagonistic epistasis, as their effects in combination upon the kinetic parameters of the three proteins in reactions with phosphoserine were nonmultiplicative. The N102T mutation exhibited sign epistasis, as it was deleterious in isolation but beneficial in the context of other mutations. We also showed that the D57N mutation in the chromosomal copy of hisB is sufficient to suppress the ?serB deletion. These results in combination show that proteomes can offer multiple mechanistic solutions to a molecular recognition problem. PMID:23728795

  11. Substrate Ambiguous Enzymes within the Escherichia coli Proteome Offer Different Evolutionary Solutions to the Same Problem

    PubMed Central

    Yip, Sylvia Hsu-Chen; Matsumura, Ichiro

    2013-01-01

    Many enzymes exhibit some catalytic promiscuity or substrate ambiguity. These weak activities do not affect the fitness of the organism under ordinary circumstances, but can serve as potential evolutionary precursors of new catalytic functions. We wondered whether different proteins with the same substrate ambiguous activity evolve differently under identical selection conditions. Patrick et al. (Patrick WM, Quandt EM, Swartzlander DB, Matsumura I. 2007. Multicopy suppression underpins metabolic evolvability. Mol Biol Evol. 24:27162722.) previously showed that three multicopy suppressors, gph, hisB, and ytjC, rescue ?serB Escherichia coli cells from starvation on minimal media. We directed the evolution of variants of Gph, histidinol phosphatase (HisB), and YtjC that complemented ?serB more efficiently, and characterized the effects of the amino acid changes, alone and in combination, upon the evolved phosphoserine phosphatase (PSP) activity. Gph and HisB are members of the HAD superfamily of hydrolases, but they adapted through different, kinetically distinguishable, biochemical mechanisms. All of the selected mutations, except N102T in YtjC, proved to be beneficial in isolation. They exhibited a pattern of antagonistic epistasis, as their effects in combination upon the kinetic parameters of the three proteins in reactions with phosphoserine were nonmultiplicative. The N102T mutation exhibited sign epistasis, as it was deleterious in isolation but beneficial in the context of other mutations. We also showed that the D57N mutation in the chromosomal copy of hisB is sufficient to suppress the ?serB deletion. These results in combination show that proteomes can offer multiple mechanistic solutions to a molecular recognition problem. PMID:23728795

  12. Method for ambiguity resolution in range-Doppler measurements

    NASA Technical Reports Server (NTRS)

    Heymsfield, Gerald M. (inventor); Miller, Lee S. (inventor)

    1994-01-01

    A method for resolving range and Doppler target ambiguities when the target has substantial range or has a high relative velocity in which a first signal is generated and a second signal is also generated which is coherent with the first signal but at a slightly different frequency such that there exists a difference in frequency between these two signals of Delta f(sub t). The first and second signals are converted into a dual-frequency pulsed signal, amplified, and the dual-frequency pulsed signal is transmitted towards a target. A reflected dual-frequency signal is received from the target, amplified, and changed to an intermediate dual-frequency signal. The intermediate dual-frequency signal is amplified, with extracting of a shifted difference frequency Delta f(sub r) from the amplified intermediate dual-frequency signal done by a nonlinear detector. The final step is generating two quadrature signals from the difference frequency Delta f(sub t) and the shifted difference frequency Delta f(sub r) and processing the two quadrature signals to determine range and Doppler information of the target.

  13. 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

  14. The effects of acute pharmacological stimulation of the 5-HT, NA and DA systems on the cognitive judgement bias of rats in the ambiguous-cue interpretation paradigm.

    PubMed

    Rygula, Rafal; Papciak, Justyna; Popik, Piotr

    2014-07-01

    In the present study, we investigated the effects of acute pharmacological stimulation of the serotonergic (5-HT), noradrenergic (NA) and dopaminergic (DA) systems on the valence of cognitive judgement bias of rats in the ambiguous-cue interpretation (ACI) paradigm. To accomplish this goal, after initial behavioural training, different groups of rats received single injections of citalopram, desipramine or d-amphetamine and were subsequently tested with the ACI paradigm. Each drug was administered in 3 doses using a fully randomised Latin square design. Citalopram at the dose of 1mg/kg significantly biased animals towards positive interpretation of the ambiguous cue, while at higher doses (5 and 10mg/kg), the animals interpreted the ambiguous cue more negatively. Desipramine at all 3 tested doses (1, 2 and 5mg/kg) significantly biased animals towards negative interpretation of the ambiguous cue, while d-amphetamine at the dose of 1mg/kg induced positive bias, having no effects at lower doses (0.1 and 0.5mg/kg). Our results indicate that cognitive bias in rats can be influenced by acute pharmacological intervention. PMID:24503278

  15. Global positioning system network analysis with phase ambiguity resolution applied to crustal deformation studies in California

    NASA Technical Reports Server (NTRS)

    Dong, Da-Nan; Bock, Yehuda

    1989-01-01

    An efficient algorithm is developed for multisession adjustment of GPS data with simultaneous orbit determination and ambiguity resolution. Application of the algorithm to the analysis of data from a five-year campaign in progress in southern and central California to monitor tectonic motions using observations by GPS satellites, demonstrates improvements in estimates of station position and satellite orbits when the phase ambiguities are resolved. Most of the phase ambiguities in the GPS network were resolved, particularly for all the baselines of geophysical interest in California.

  16. Phase-ambiguity resolution for QPSK modulation systems. Part 1: A review

    NASA Technical Reports Server (NTRS)

    Nguyen, Tien Manh

    1989-01-01

    Part 1 reviews the current phase-ambiguity resolution techniques for QPSK coherent modulation systems. Here, those known and published methods of resolving phase ambiguity for QPSK with and without Forward-Error-Correcting (FEC) are discussed. The necessary background is provided for a complete understanding of the second part where a new technique will be discussed. An appropriate technique to the Consultative Committee for Space Data Systems (CCSDS) is recommended for consideration in future standards on phase-ambiguity resolution for QPSK coherent modulation systems.

  17. 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)

  18. Ambiguity and workarounds as contributors to medical error.

    PubMed

    Spear, Steven J; Schmidhofer, Mark

    2005-04-19

    Why are some organizations error-prone-regularly subject to interruptions and inconveniences, some of which periodically coalesce catastrophically-whereas other organizations, although similar in the products and services they generate and the process technologies they use, are reliable, adaptable, and continuously self-improving, relentlessly learning from experience to get ever better? Analyzing medical error reports and studies of high-performing, non-health care organizations reveals 2 differences. High performers know how to prevent problems from producing further consequences once they occur and how to prevent their recurrence. They do this by specifying how work is expected to proceed-who will do what for whom, with what purpose, when, where, and how-before work is actually done. Then, when anything contrary to expectations occurs, it is immediately identified as a problem. Through this approach, the effects of problems are contained, the causes are quickly investigated, process knowledge is deepened, and recurrence is prevented. In contrast, error-prone organizations tolerate ambiguity, a prevailing lack of clarity over what is supposed to happen at any given time. Problems are thus hard to identify, and, even when recognized, they are worked around. People "get the job done," but don't initiate efforts to learn from the problem or improve the process. We believe that coupling high degrees of specification with rapid responses to individual problems can improve health care. Superlative manufacturing, service, and military organizations apply this approach to myriad processes and situations, and initial health care trials of this approach have been promising. We discuss how such an approach could be initiated in health care more broadly. PMID:15838069

  19. Dynamic resolution of ambiguity during tri-stable motion perception.

    PubMed

    Meso, Andrew Isaac; Masson, Guillaume S

    2015-02-01

    Multi-stable perception occurs when an image falling onto the retina has multiple incompatible interpretations. We probed this phenomenon in psychophysical experiments using a moving barber-pole visual stimulus configured as a square to generate three competing perceived directions, horizontal, diagonal and vertical. We characterised patterns in reported switching type and percept duration, classifying switches into three groups related to the direction cues driving such transitions i.e. away from diagonal, towards diagonal and between cardinals. The proportions of each class reported by participants depended on contrast. The two including diagonals dominated at low contrast and those between cardinals increased in proportion as contrast was increased. At low contrasts, the less frequent cardinals persisted for shorter than the dominant diagonals and this was reversed at higher contrasts. This observed asymmetry between the dominance of transition classes appears to be driven by different underlying dynamics between cardinal and the oblique cues and their related transitions. At trial onset we found that transitions away from diagonal dominate, a tendency which later in the trial reverses to dominance by transitions excluding the diagonal, most prominently at higher contrasts. Thus ambiguity is resolved over a contrast dependent temporal integration similar to, but lasting longer than that observed when resolving the aperture problem to estimate direction. When the diagonal direction dominates perception, evidence is found for a noisier competition seen in broader duration distributions than during dominance of cardinal perception. There remain aspects of these identified differences in cardinal and oblique dynamics to be investigated in future. PMID:25555566

  20. Priming the interpretation of ambiguous noun-noun compounds in young children

    E-print Network

    Fialka, Justine K B

    2010-06-30

    Abstract: Investigation into adult language users interpretation of ambiguous noun-noun compounds has been considerably explored and documented. However, investigation into the same phenomenon in a population such as young children has been...

  1. Health messaging to individuals who perceive ambiguity in health communications: the promise of self-affirmation.

    PubMed

    Klein, William M P; Hamilton, Jada G; Harris, Peter R; Han, Paul K J

    2015-05-01

    The perception that extant health messages about risk factors for a disease are ambiguous can be associated with greater anxiety and reduced interest in taking precautionary action. In this experiment, 247 female alcohol consumers who perceived varying degrees of ambiguity in current cancer prevention messages read an unambiguous article about the documented link between alcohol consumption and breast cancer. Before reading the article, half were given the opportunity to self-affirm by reflecting on an important value-a technique previously shown to enhance receptivity to threatening messages. The authors found that self-affirmation increased message acceptance among those who perceived relatively higher levels of ambiguity in cancer communications. Also, the relation between perceived ambiguity and risk perception became positive among self-affirmed participants, suggesting they had become less defensive. Self-affirmation may be an effective technique to use when delivering health communications to audiences who perceive a lack of consistency in prevention messages. PMID:25806652

  2. Design criteria for purposefully ambiguous expression : proposal for a theater / performing arts school in Kenmore Square

    E-print Network

    Verhulst, Catharina A

    1986-01-01

    Inclusion of zones which possess sufficient ambiguity to provide multiple use, character and meaning, generating an environment supporting freedom of interpretation and expression, is explored in this thesis. Conceptually, ...

  3. Resolving the Azimuthal Ambiguity in Vector Magnetogram Data with the Divergence-Free Condition: Theoretical Examination

    NASA Technical Reports Server (NTRS)

    Crouch, A.; Barnes, G.

    2008-01-01

    We demonstrate that the azimuthal ambiguity that is present in solar vector magnetogram data can be resolved with line-of-sight and horizontal heliographic derivative information by using the divergence-free property of magnetic fields without additional assumptions. We discuss the specific derivative information that is sufficient to resolve the ambiguity away from disk center, with particular emphasis on the line-of-sight derivative of the various components of the magnetic field. Conversely, we also show cases where ambiguity resolution fails because sufficient line-of-sight derivative information is not available. For example, knowledge of only the line-of-sight derivative of the line-of-sight component of the field is not sufficient to resolve the ambiguity away from disk center.

  4. What difference does a robot make? managing ambiguity in distributed knowledge work

    E-print Network

    Beane, Matthew I. (Matthew Ian)

    2014-01-01

    What difference does robotic telepresence make to the management of ambiguity in distributed knowledge work? We examined this question in a post-surgical intensive care where remote medical workers struggled to coordinate ...

  5. Learning from Ambiguously Labeled Images Timothee Cour Ben Sapp Chris Jordan Ben Taskar

    E-print Network

    Plotkin, Joshua B.

    of State in Barack Obama's administration." Ex 2: People on TV Ex 1: Photograph Collections weak form and closed captions set of speakers in scene Obama? Clinton? Obama? Clinton? Obama Clinton ambiguous

  6. Illusions and Ambiguities in the Telemedia Environment: An Exploration of the Transformation of Social Roles.

    ERIC Educational Resources Information Center

    Davis, Dineh M.

    1995-01-01

    Focuses on the ambiguities in the fluid human-telemedia infrastructure. Suggests the need for new signposts to guide our understanding of this environment and the changes it will bring to social roles. (Author)

  7. Predictors of Perceived Ambiguity About Cancer Prevention Recommendations: Sociodemographic Factors and Mass Media Exposures

    PubMed Central

    Han, Paul K. J.; Moser, Richard P.; Klein, William M. P.; Beckjord, Ellen Burke; Dunlavy, Andrea C.; Hesse, Bradford W.

    2014-01-01

    Cancer prevention recommendations reaching the public today are often ambiguousthat is, of uncertain reliability, credibility, or adequacyyet little is known about the factors that influence public perceptions of this ambiguity. We used data from the 2005 Health Information National Trends Survey, conducted by the U.S. National Cancer Institute, to explore how sociodemographic characteristics and self-reported mass media exposures relate to perceptions of ambiguity regarding recommendations for the prevention of colon, skin, and lung cancer. Various sociodemographic characteristics (age, education, race) and mass media exposures (television, radio, Internet, health news) were found to be associated with perceived ambiguity about cancer prevention recommendations, and many of these associations varied by cancer type. These findings have important implications for future health communication research and practice. PMID:20183385

  8. The relationships among sex-role orientation, cognitive complexity, and tolerance for ambiguity

    Microsoft Academic Search

    Naomi G. Rotter; Agnes N. O'Connell

    1982-01-01

    Two hundred and four female and eighty-seven male college students completed the Schroder and Streufert measure of cognitive complexity, Budner's Intolerance for Ambiguity Scale, and Bem's Sex Role Inventory (BSRI). It was hypothesized that subjects classified as androgynous and as cross-sexed would be more cognitively complex and more tolerant of ambiguity than sex-typed or undifferentiated subjects; and cognitive complexity and

  9. 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

  10. How meaning similarity influences ambiguous word processing: the current state of the literature.

    PubMed

    Eddington, Chelsea M; Tokowicz, Natasha

    2015-02-01

    The majority of words in the English language do not correspond to a single meaning, but rather correspond to two or more unrelated meanings (i.e., are homonyms) or multiple related senses (i.e., are polysemes). It has been proposed that the different types of "semantically-ambiguous words" (i.e., words with more than one meaning) are processed and represented differently in the human mind. Several review papers and books have been written on the subject of semantic ambiguity (e.g., Adriaens, Small, Cottrell, & Tanenhaus, 1988; Burgess & Simpson, 1988; Degani & Tokowicz, 2010; Gorfein, 1989, 2001; Simpson, 1984). However, several more recent studies (e.g., Klein & Murphy, 2001; Klepousniotou, 2002; Klepousniotou & Baum, 2007; Rodd, Gaskell, & Marslen-Wilson, 2002) have investigated the role of the semantic similarity between the multiple meanings of ambiguous words on processing and representation, whereas this was not the emphasis of previous reviews of the literature. In this review, we focus on the current state of the semantic ambiguity literature that examines how different types of ambiguous words influence processing and representation. We analyze the consistent and inconsistent findings reported in the literature and how factors such as semantic similarity, meaning/sense frequency, task, timing, and modality affect ambiguous word processing. We discuss the findings with respect to recent parallel distributed processing (PDP) models of ambiguity processing (Armstrong & Plaut, 2008, 2011; Rodd, Gaskell, & Marslen-Wilson, 2004). Finally, we discuss how experience/instance-based models (e.g., Hintzman, 1986; Reichle & Perfetti, 2003) can inform a comprehensive understanding of semantic ambiguity resolution. PMID:24889119

  11. Rapid re-convergences to ambiguity-fixed solutions in precise point positioning

    NASA Astrophysics Data System (ADS)

    Geng, Jianghui; Meng, Xiaolin; Dodson, Alan H.; Ge, Maorong; Teferle, Felix N.

    2010-12-01

    Integer ambiguity resolution at a single receiver can be achieved if the fractional-cycle biases are separated from the ambiguity estimates in precise point positioning (PPP). Despite the improved positioning accuracy by such integer resolution, the convergence to an ambiguity-fixed solution normally requires a few tens of minutes. Even worse, these convergences can repeatedly occur on the occasion of loss of tracking locks for many satellites if an open sky-view is not constantly available, consequently totally destroying the practicability of real-time PPP. In this study, in case of such re-convergences, we develop a method in which ionospheric delays are precisely predicted to significantly accelerate the integer ambiguity resolution. The effectiveness of this method consists in two aspects: first, wide-lane ambiguities can be rapidly resolved using the ionosphere-corrected wide-lane measurements, instead of the noisy Melbourne-Wbbena combination measurements; second, narrow-lane ambiguity resolution can be accelerated under the tight constraints derived from the ionosphere-corrected unambiguous wide-lane measurements. In the test at 90 static stations suffering from simulated total loss of tracking locks, 93.3 and 95.0% of re-convergences to wide-lane and narrow-lane ambiguity resolutions can be achieved within five epochs of 1-Hz measurements, respectively, even though the time latency for the predicted ionospheric delays is up to 180 s. In the test at a mobile van moving in a GPS-adverse environment where satellite number significantly decreases and cycle slips frequently occur, only when the predicted ionospheric delays are applied can the rate of ambiguity-fixed epochs be dramatically improved from 7.7 to 93.6% of all epochs. Therefore, this method can potentially relieve the unrealistic requirement of a continuous open sky-view by most PPP applications and improve the practicability of real-time PPP.

  12. The descriptive and predictive adequacy of theories of decision making under uncertainty\\/ambiguity

    Microsoft Academic Search

    John D. Hey; Gianna Lotito; Anna Maffioletti

    2010-01-01

    In this paper we examine the performance of theories of decision making under uncertainty\\/ambiguity from the perspective of\\u000a their descriptive and predictive power. To this end, we employ an innovative experimental design which enables us to reproduce\\u000a ambiguity in the laboratory in a transparent and non-probabilistic way. We find that judging theories on the basis of their\\u000a theoretical appeal, or

  13. Family boundary ambiguity and the measurement of family structure: the significance of cohabitation

    Microsoft Academic Search

    Susan L. Brown; Wendy D. Manning

    2009-01-01

    We used data from the first wave of the National Longitudinal Study of Adolescent Health to examine family boundary ambiguity\\u000a in adolescent and mother reports of family structure and found that the greater the family complexity, the more likely adolescent\\u000a and mother reports of family structure were discrepant. This boundary ambiguity in reporting was most pronounced for cohabiting\\u000a stepfamilies. Among

  14. An overview of information giving in fertility clinics.

    PubMed

    Mounce, Ginny

    2013-03-01

    Information giving is a key aspect of the provision of high-quality patient-centred health care, resulting in patients who are well-informed, better adjusted to their circumstances and are compliant with their treatment. Fertility patients generally appear to be satisfied with the information they are given but a significant minority are not. Giving information to infertile patients is complicated by the nature of their condition, desire for a child and complexity of treatment options. Patients need detailed, well-timed information to support difficult decision-making, such as when to end treatment. The experiences of some individual patients and particular sub-groups in receiving and understanding information suggest that the quality of information or the way it is communicated could be improved. It is suggested that this may be achieved by reviewing the format and timing of the information provided, ensuring adequate staff training and facilitating flexibility in clinic organisation. PMID:23360453

  15. Resolving the Ambiguity of Volatile Content in the Vestan Regolith through Dielectric Inversion

    NASA Astrophysics Data System (ADS)

    Palmer, E. M.; Heggy, E.; Capria, M.; Asmar, S.; Raymond, C. A.; Russell, C. T.

    2012-12-01

    In the summer of 2011, Dawn entered orbit around 4 Vesta. An evolved and differentiated body, Vesta has been described as more of a proto-planet than an asteroid, and is similar in surface composition and history to the Moon. While differentiated and airless bodies such as these were assumed to have depleted any initial water content, recent missions to the Moon have discovered water at the poles and hydroxyl more generally across the surface. At Vesta, recent results from GRaND suggest a correlation of higher hydrogen concentrations at the regions of dark material on the surface, indicating volatile presence. An interesting topic of concern, therefore, is the form and quantification of this volatile content in regions of dark material at the surface and shallow subsurface of the Vestan regolith. Toward this end, the Dawn bistatic radar experiment, as well as Earth-based radar observations of Vesta, can quantify backscattering properties of the surface through the resulting amplitude, polarimetric and phase change of their radar waves. These waves are primarily affected by surface topography, roughness, and electromagnetic properties that vary with surface composition and geophysical properties. This results in a sensitivity to textural and dielectric variations, which could indicate compositional variation and/or signs of volatile enrichment. However, since surface roughness (textural variation) is poorly constrained, Earth-based radar observations yield large uncertainties when inferring dielectric properties. To address the resulting ambiguity, we model the dielectric properties of the regolith based on two complementary approaches: (1) dielectric laboratory measurement of spectral analogs to the dark material at various frequencies, temperatures, porosities, and dust-to-ice mass ratios; and (2) modeling of the dielectric constant distribution when combined with the inversion of calculated thermal inertia values. From this dielectric model we are able to invert surface roughness, which is then used to reduce ambiguity in dielectric properties inferred through radar observations. This generates a new dielectric model, which can then be used to validate that based on laboratory measurements and thermal inertia.

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

    PubMed Central

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

    2011-01-01

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

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

    ERIC Educational Resources Information Center

    Brecke, Ronald; Jensen, Jacy

    2007-01-01

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

  18. TIPS FOR GIVING A GOOD MBP STUDENT

    E-print Network

    Woodgett, Jim

    Project Modify our Optical Spectroscopy device and data analysis techniques to make it more suitable is a hypothesis/question Don't need to cover your entire project Methods and Results Not too much data are you trying to add to the big picture Mention key take-home points Breast Cancer Risk Lifetime risk

  19. BOSTONIA Fall 2013 will give Boston University

    E-print Network

    Spence, Harlan Ernest

    , to field trips, or to additional lectures delving more deeply into topics. O'Connell says early results worlds," says Loizeaux, a College of Arts & Sciences professor of English. "It promotes the face) for free. Here's how it works. #12;Fall 2013 BOSTONIA Athletes Excel in NCAA Academic Ranking Perfect

  20. 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

  1. Study Gives Edge to 2 Math Programs

    ERIC Educational Resources Information Center

    Viadero, Debra

    2009-01-01

    This article reports that two programs for teaching mathematics in the early grades--Math Expressions and Saxon Math--emerged as winners in early findings released last week from a large-scale federal experiment that pits four popular, and philosophically distinct, math curricula against one another. But the results don't promise to end the

  2. 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.

  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.

    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.

  4. Saharan dust gives clues to weather patterns

    NSDL National Science Digital Library

    Sun Wong

    The influence of the Saharan Air Layer (SAL) on convection over the Atlantic Ocean west of Africa was investigated using satellite measurements of atmospheric temperature and moisture and of dust concentrations in the SAL. Results suggest that dust is not an effective proxy to track the SAL as it moves west and that other tracking techniques are required to track the air mass as it moves far from the continent.

  5. Giving students the run of sprinting models

    NASA Astrophysics Data System (ADS)

    Heck, Andr; 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.

  6. Microfluidic processor allows rapid HER2 immunohistochemistry of breast carcinomas and significantly reduces ambiguous (2+) read-outs

    PubMed Central

    Ciftlik, Ata Tuna; Lehr, Hans-Anton; Gijs, Martin A. M.

    2013-01-01

    Biomarker analysis is playing an essential role in cancer diagnosis, prognosis, and prediction. Quantitative assessment of immunohistochemical biomarker expression on tumor tissues is of clinical relevance when deciding targeted treatments for cancer patients. Here, we report a microfluidic tissue processor that permits accurate quantification of the expression of biomarkers on tissue sections, enabled by the ultra-rapid and uniform fluidic exchange of the device. An important clinical biomarker for invasive breast cancer is human epidermal growth factor receptor 2 [(HER2), also known as neu], a transmembrane tyrosine kinase that connotes adverse prognostic information for the patients concerned and serves as a target for personalized treatment using the humanized antibody trastuzumab. Unfortunately, when using state-of-the-art methods, the intensity of an immunohistochemical signal is not proportional to the extent of biomarker expression, causing ambiguous outcomes. Using our device, we performed tests on 76 invasive breast carcinoma cases expressing various levels of HER2. We eliminated more than 90% of the ambiguous results (n = 27), correctly assigning cases to the amplification status as assessed by in situ hybridization controls, whereas the concordance for HER2-negative (n = 31) and -positive (n = 18) cases was 100%. Our results demonstrate the clinical potential of microfluidics for accurate biomarker expression analysis. We anticipate our technique will be a diagnostic tool that will provide better and more reliable data, onto which future treatment regimes can be based. PMID:23479638

  7. Giving Bad News: A Qualitative Research Exploration

    PubMed Central

    Aein, Fereshteh; Delaram, Masoumeh

    2014-01-01

    Background: The manner in which healthcare professionals deliver bad news affects the way it is received, interpreted, understood, and dealt with. Despite the fact that clinicians are responsible for breaking bad news, it has been shown that they lack skills necessary to perform this task. Objectives: The purpose of this study was to explore Iranian mothers experiences to receive bad news about their children cancer and to summarize suggestions for improving delivering bad news by healthcare providers. Materials and Methods: A qualitative approach using content analysis was adopted. Semi-structured interviews were conducted with 14 mothers from two pediatric hospitals in Iran. Results: Five major categories emerged from the data analysis, including dumping information, shock and upset, emotional work, burden of delivering bad news to the family members, and a room for multidisciplinary approach. Conclusions: Effective communication of healthcare team with mothers is required during breaking bad news. Using multidisciplinary approaches to prevent harmful reactions and providing appropriate support are recommended. PMID:25068066

  8. The surgical management of infants and children with ambiguous genitalia. Lessons learned from 25 years.

    PubMed Central

    Newman, K; Randolph, J; Anderson, K

    1992-01-01

    Over a 25-year period, 91 children with ambiguous genitalia have received surgical management. Female sex assignment was made for 79. Of these, 60 patients underwent extensive clitoral reconstruction consonant with the female assignment. Forty-two patients had vaginal reconstruction. Factors relating to success include: (1) prompt and appropriate sex assignment; (2) early and accurate diagnosis; (3) conservative reconstruction of the clitoris at an early age (less than 1 year); and (4) choice of vaginal reconstruction based on the severity of the malformation. Long-term follow-up demonstrates satisfactory anatomic and functional results when clitoral surgery alone was required. Functional results for patients with extensive vaginal reconstruction have been compromised. Physicians caring for children with congenital intersexual anomalies can expect to encounter a wide spectrum of anatomic and physiologic derangements. Cosmetic appearance alone is an inadequate measure of success because endocrinologic, social, psychological, and sexual factors must be blended into comprehensive evaluation of these patients. The management plan must be flexible and individualized, incorporating long-term follow-up to adulthood. Images FIG. 1. FIG. 2. FIG. 3. FIG. 4. FIG. 5. FIG. 6. FIG. 7. FIG. 8. FIG. 8. FIG. 8. FIG. 9. FIG. 10. FIG. 11. PMID:1632686

  9. 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.

  10. Study of ambiguities in $\\pi^-p\\to \\Lambda K^0$ scattering amplitudes

    E-print Network

    Anisovich, A V; Klempt, E; Nikonov, V A; Sarantsev, A V; Thoma, U; Wunderlich, Y

    2013-01-01

    Amplitudes for the reaction $\\pi^-p\\to \\Lambda K^0$ are reconstructed from data on the differential cross section $d\\sigma/d\\Omega$, the recoil polarization $P$, and on the spin rotation parameter $\\beta$. At low energies, no data on $\\beta$ exist, resulting in ambiguities. An approximation using $S$ and $P$ waves leads only to a fair description of the data on $d\\sigma/d\\Omega$ and $P$; in this case, there are two sets of amplitudes. Including $D$ waves, the data on $d\\sigma/d\\Omega$ and $P$ are well reproduced by the fit but now, there are several distinct solutions which describe the data with identical precision. In the range where the spin rotation parameter $\\beta$ was measured, a full and unambiguous reconstruction of the partial wave amplitudes is possible. The energy-independent amplitudes are compared to the energy dependent amplitudes which resulted from a coupled channel fit (BnGa2011-02) to a large data set including both pion and photo-induced reactions. Significant deviations are observed. Cons...

  11. Foul or dive? Motor contributions to judging ambiguous foul situations in football.

    PubMed

    Renden, Peter G; Kerstens, Sander; Oudejans, Raul R D; Caal-Bruland, Rouwen

    2014-01-01

    Football (soccer) referees frequently face situations in which they have to distinguish dives and fouls. Yet, little is known about the contributing factors that characterise the ability to judge these ambiguous situations correctly. To this end, in the current article we tested the hypothesis that motor experience of observers contributes to the visual identification of deceptive actions. Thereto, we asked skilled football referees, skilled football players, wheelchair bounded football fans (thus with limited motor experience) and novices to judge whether potential tackle situations in football were either fouls or dives. Results revealed that the referees (accuracy 72.2%, s=6.2) and players (accuracy 72.0%, s=6.4) were better at discriminating fouls and dives than the fans (accuracy 61.1%, s=7.2) and the novices (accuracy 57.4%, s=7.0) (P < 0.001). The results seem to point to an added value of motor experience in detecting deceptive movements. PMID:24444210

  12. Formulas Giving Buildup Factor for Double-Layered Shields

    SciTech Connect

    Guvendik, Mevlut; Tsoulfanidis, Nicholas [University of Missouri-Rolla (United States)

    2000-09-15

    Formulas that give absorbed dose buildup factors for two-layered shields have been developed based on gamma-ray absorption buildup factors computed with the Monte Carlo Neutral Particle Transport Code System (MCNP). The shielding materials considered were water, lead, steel, concrete, and some of their combinations for two-layered shields with thicknesses between 1 to 10 mfp. Gamma energy considered ranged from 0.5 to 6 MeV. The formulas reproduce MCNP results with a difference of <10%, in most cases <3%.

  13. "How about giving my things away over the Internet?" When Internet makes it easier to give things away

    E-print Network

    Paris-Sud XI, Université de

    1 "How about giving my things away over the Internet?" When Internet makes it easier to give things Away Over the Internet? When the Internet Makes It Easier to Give Things Away", in NA - Advances of Management, France [ to cite ]: Valérie Guillard and Céline Del Bucchia (2012) ,"How About Giving My Things

  14. Reduction of the ambiguity of karst aquifer modeling through pattern matching of groundwater flow and transport

    NASA Astrophysics Data System (ADS)

    Oehlmann, Sandra; Geyer, Tobias; Licha, Tobias; Sauter, Martin

    2014-05-01

    Distributive numerical simulations are an effective, process-based method for predicting groundwater resources and quality. They are based on conceptual hydrogeological models that characterize the properties of the catchment area and aquifer. Karst systems play an important role in water supply worldwide. Conceptual models are however difficult to build because of the highly developed heterogeneity of the systems. The geometry and properties of highly conductive karst conduits are generally unknown and difficult to characterize with field experiments. Due to these uncertainties numerical models of karst areas usually cannot simulate the hydraulic head distribution in the area, spring discharge and tracer breakthrough curves simultaneously on catchment scale. Especially in complex hydrogeological systems, this approach would reduce model ambiguity, which is prerequisite to predict groundwater resources and pollution risks. In this work, a distributive numerical groundwater flow and transport model was built for a highly heterogeneous karst aquifer in south-western Germany. For this aim, a solute transport interface for one-dimensional pipes was implemented in the software Comsol Multiphysics and coupled to the standard three-dimensional solute transport interface for domains. The model was calibrated and hydraulic parameters could be obtained. The simulation was matched to the steady-state 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 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 analyze their influence 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 to be employed as a prognostic tool 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, even though standard tracer test evaluations predicted a volume of up to 200 000 m3.

  15. 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 outburst of Sakurai's Object is the first such blast seen in modern times. Stellar outbursts observed in 1670 and 1918 may have been caused by the same phenomenon. Astronomers expect the Sun to become a white dwarf in about five billion years. A white dwarf is a dense core left after a star's normal, fusion-powered life has ended. A teaspoon of white dwarf material would weigh about 10 tons. White dwarfs can have masses up to 1.4 times that of the Sun; larger stars collapse at the end of their lives into even-denser neutron stars or black holes. Computer simulations indicated that heat-spurred convection (or "boiling") would bring hydrogen from the star's outer envelope down into the helium shell, driving a brief flash of new nuclear fusion. This would cause a sudden increase in brightness. The original computer models suggested a sequence of observable events that would occur over a few hundred years. "Sakurai's object went through the first phases of this sequence in just a few years -- 100 times faster than we expected -- so we had to revise our models," Zijlstra said. The revised models predicted that the star should rapidly reheat and begin to ionize gases in its surrounding region. "This is what we now see in our latest VLA observations," Zijlstra said. "It's important to understand this process. Sakurai's Object has ejected a large amount of the carbon from its inner core into space, both in the form of gas and dust grains. These will find their way into regions of space where new stars form, and the dust grains may become incorporated in new planets. Some carbon grains found in a meteorite show isotope ratios identical to those found in Sakurai's Object, and we think they may have come from such an event. Our results suggest this source for cosmic carbon may be far more important than we suspected before," Zijlstra added. The scientists continue to observe Sakurai's Object to take advantage of the rare opportunity to learn about the process of re-ignition. They are making new VLA observations just

  16. Various Ambiguities in Re-constructing Laser Pulse Parameters

    NASA Technical Reports Server (NTRS)

    Roychoudhuri, Chandrasekhar; Prasa, Narasimha

    2006-01-01

    We think that mode lock laser pulses are generated by the summation process that take place between the monochromatic EM filed frequencies as if they interact with each other as shown in equation 1. In reality, the pulse generation is a collaborative interaction process between EM fields and various material medium. When we carry out the actual mode lock analysis, we do take into account of interpaly between all the temporal dynamics of the cavity gain medium, cavity round trip time and the response time of the intra cavity element (saturable absorber, Kerr medium, etc.). that really enforces the locking of the phase of the cavity spontaneous emissions. On a conceptual level, this simplistic representation of the mode locking by Eq.1 ignores all these critical physical processes. When we try to analyze a pulsed field, again we start by representing it very much like this equation, even though we can only detect the square modulus of this complex field and loose a lot of phase related information to the detectors quantum whims and their time constants. The key parameters for a light pulse are as follows. Foremost is the (i) carrier frequency, which cannot be described or imagined without its state of undulation expressed as its (ii) phase. Next is our imagined time finite (iii) carrier envelope that provides the temporal boundary of the field amplitude strength of the undulating E-field. The final parameter is the (iv) state of polarization or the unique plane along which the strength of the E-field gradient undulates. None of these filed characteristics are made self-evident to us by the fields themselves. We do not see light. Light does not see light. Light beams pass through each other without altering each others energy distribution unless there are interacting material molecules (dipoles) within the physical volume of superposition of the beams. In contrast, we can sense the material particles. Material particles sense each other and they cannot pass through 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.

  17. 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

    2012-01-01

    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 then look for areas in the brain whose activation is correlated with the subjective value of risky options and for areas whose activation is correlated with the subjective value of ambiguous options. PMID:23022992

  18. Enhancement of Directional Ambiguity Removal Skill in Scatterometer Data Processing Using Planetary Boundary Layer Models

    NASA Technical Reports Server (NTRS)

    Kim, Young-Joon; Pak, Kyung S.; Dunbar, R. Scott; Hsiao, S. Vincent; Callahan, Philip S.

    2000-01-01

    Planetary boundary layer (PBL) models are utilized to enhance directional ambiguity removal skill in scatterometer data processing. The ambiguity in wind direction retrieved from scatterometer measurements is removed with the aid of physical directional information obtained from PBL models. This technique is based on the observation that sea level pressure is scalar and its field is more coherent than the corresponding wind. An initial wind field obtained from the scatterometer measurements is used to derive a pressure field with a PBL model. After filtering small-scale noise in the derived pressure field, a wind field is generated with an inverted PBL model. This derived wind information is then used to remove wind vector ambiguities in the scatterometer data. It is found that the ambiguity removal skill can be improved when the new technique is used properly in conjunction with the median filter being used for scatterometer wind dealiasing at JPL. The new technique is applied to regions of cyclone systems which are important for accurate weather prediction but where the errors of ambiguity removal are often large.

  19. Rate-gyro-integral constraint for ambiguity resolution in GNSS attitude determination applications.

    PubMed

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

    2013-01-01

    In the field of Global Navigation Satellite System (GNSS) attitude determination, the constraints usually play a critical role in resolving the unknown ambiguities quickly and correctly. Many constraints such as the baseline length, the geometry of multi-baselines and the horizontal attitude angles have been used extensively to improve the performance of ambiguity resolution. In the GNSS/Inertial Navigation System (INS) integrated attitude determination systems using low grade Inertial Measurement Unit (IMU), the initial heading parameters of the vehicle are usually worked out by the GNSS subsystem instead of by the IMU sensors independently. However, when a rotation occurs, the angle at which vehicle has turned within a short time span can be measured accurately by the IMU. This measurement will be treated as a constraint, namely the rate-gyro-integral constraint, which can aid the GNSS ambiguity resolution. We will use this constraint to filter the candidates in the ambiguity search stage. The ambiguity search space shrinks significantly with this constraint imposed during the rotation, thus it is helpful to speeding up the initialization of attitude parameters under dynamic circumstances. This paper will only study the applications of this new constraint to land vehicles. The impacts of measurement errors on the effect of this new constraint will be assessed for different grades of IMU and current average precision level of GNSS receivers. Simulations and experiments in urban areas have demonstrated the validity and efficacy of the new constraint in aiding GNSS attitude determinations. PMID:23793044

  20. High fives motivate: the effects of gestural and ambiguous verbal praise on motivation.

    PubMed

    Morris, Bradley J; Zentall, Shannon R

    2014-01-01

    The type of praise children receive influences whether children choose to persist after failure. One mechanism through which praise affects motivation is through the causal attributions inferred from language. For example, telling a child "You got an A on the test because you're smart," provides an explicit link between possessing a trait and an outcome, specifically that intelligence causes success. Nonetheless, most praise given to children is ambiguous, or lacks explicit attributions (e.g., "yea" or a thumbs up). To investigate the effects of ambiguous praise on motivation, we randomly assigned 95 5-6-year-old children to a praise condition (verbal trait; verbal effort; verbal ambiguous; or gestural) and measured motivation using task persistence, self-evaluations, and eye fixations on errors. Ambiguous praise, similar to verbal effort praise, produced higher persistence and self-evaluations, and fewer fixations on error after failure compared to verbal trait praise. Interestingly, gestures produced the highest self-evaluations. Thus, praise without explicit attributions motivated as well or better than praise explicitly focused on effort, which may suggest that children interpret ambiguous praise in the most beneficial manner. PMID:25221532

  1. High fives motivate: the effects of gestural and ambiguous verbal praise on motivation

    PubMed Central

    Morris, Bradley J.; Zentall, Shannon R.

    2014-01-01

    The type of praise children receive influences whether children choose to persist after failure. One mechanism through which praise affects motivation is through the causal attributions inferred from language. For example, telling a child You got an A on the test because youre smart, provides an explicit link between possessing a trait and an outcome, specifically that intelligence causes success. Nonetheless, most praise given to children is ambiguous, or lacks explicit attributions (e.g., yea or a thumbs up). To investigate the effects of ambiguous praise on motivation, we randomly assigned 95 56-year-old children to a praise condition (verbal trait; verbal effort; verbal ambiguous; or gestural) and measured motivation using task persistence, self-evaluations, and eye fixations on errors. Ambiguous praise, similar to verbal effort praise, produced higher persistence and self-evaluations, and fewer fixations on error after failure compared to verbal trait praise. Interestingly, gestures produced the highest self-evaluations. Thus, praise without explicit attributions motivated as well or better than praise explicitly focused on effort, which may suggest that children interpret ambiguous praise in the most beneficial manner. PMID:25221532

  2. Application of the multiple PRF technique to resolve Doppler centroid estimation ambiguity for spaceborne SAR

    NASA Technical Reports Server (NTRS)

    Chang, C. Y.; Curlander, J. C.

    1992-01-01

    Estimation of the Doppler centroid ambiguity is a necessary element of the signal processing for SAR systems with large antenna pointing errors. Without proper resolution of the Doppler centroid estimation (DCE) ambiguity, the image quality will be degraded in the system impulse response function and the geometric fidelity. Two techniques for resolution of DCE ambiguity for the spaceborne SAR are presented; they include a brief review of the range cross-correlation technique and presentation of a new technique using multiple pulse repetition frequencies (PRFs). For SAR systems, where other performance factors control selection of the PRF's, an algorithm is devised to resolve the ambiguity that uses PRF's of arbitrary numerical values. The performance of this multiple PRF technique is analyzed based on a statistical error model. An example is presented that demonstrates for the Shuttle Imaging Radar-C (SIR-C) C-band SAR, the probability of correct ambiguity resolution is higher than 95 percent for antenna attitude errors as large as 3 deg.

  3. In the face of uncertainty: a twin study of ambiguous information, anxiety and depression in children.

    PubMed

    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, anxiety and depression symptoms in 300 8-year-old twin pairs. There were significant correlations between both negative interpretations of ambiguous words and scenarios and depression symptoms after controlling for anxiety symptoms (r = .13 and .31, respectively), but no significant correlations with anxiety independent of depression. Genetic effects ranged from 16% for depression to 30% for ambiguous word interpretations. Non-shared environmental influences were large (68-70%). Both genetic and environmental influences contributed to the association between depression and ambiguous scenario interpretations. These findings support psychological theories, which emphasise the role of environmental stress both on the development of threat interpretations and on their links with symptoms. The data also support a role for genetic influence on threat interpretations, which may mediate responses to stress. PMID:17687641

  4. Childrens and Adults On-Line Processing of Syntactically Ambiguous Sentences during Reading

    PubMed Central

    Joseph, Holly S. S. L.; Liversedge, Simon P.

    2013-01-01

    While there has been a fair amount of research investigating childrens syntactic processing during spoken language comprehension, and a wealth of research examining adults syntactic processing during reading, as yet very little research has focused on syntactic processing during text reading in children. In two experiments, children and adults read sentences containing a temporary syntactic ambiguity while their eye movements were monitored. In Experiment 1, participants read sentences such as, The boy poked the elephant with the long stick/trunk from outside the cage in which the attachment of a prepositional phrase was manipulated. In Experiment 2, participants read sentences such as, I think Ill wear the new skirt I bought tomorrow/yesterday. Its really nice in which the attachment of an adverbial phrase was manipulated. Results showed that adults and children exhibited similar processing preferences, but that children were delayed relative to adults in their detection of initial syntactic misanalysis. It is concluded that children and adults have the same sentence-parsing mechanism in place, but that it operates with a slightly different time course. In addition, the data support the hypothesis that the visual processing system develops at a different rate than the linguistic processing system in children. PMID:23349807

  5. Ambiguity and judgments of obese individuals: no news could be bad news.

    PubMed

    Ross, Kathryn M; Shivy, Victoria A; Mazzeo, Suzanne E

    2009-08-01

    Stigmatization towards obese individuals has not decreased despite the increasing prevalence of obesity. Nonetheless, stigmatization remains difficult to study, given concerns about social desirability. To address this issue, this study used paired comparisons and cluster analysis to examine how undergraduates (n=189) categorized scenarios describing the health-related behaviors of obese individuals. The cluster analysis found that the scenarios were categorized into two distinct clusters. The first cluster included all scenarios with health behaviors indicating high responsibility for body weight. These individuals were perceived as unattractive, lazy, less likeable, less disciplined, and more deserving of their condition compared to individuals in the second cluster, which included all scenarios with health behaviors indicating low responsibility for body weight. Four scenarios depicted obese individuals with ambiguous information regarding health behaviors; three out of these four individuals were categorized in the high-responsibility cluster. These findings suggested that participants viewed these individuals as negatively as those who were responsible for their condition. These results have practical implications for reducing obesity bias, as the etiology of obesity is typically not known in real-life situations. PMID:19665097

  6. Children's and adults' on-line processing of syntactically ambiguous sentences during reading.

    PubMed

    Joseph, Holly S S L; Liversedge, Simon P

    2013-01-01

    While there has been a fair amount of research investigating children's syntactic processing during spoken language comprehension, and a wealth of research examining adults' syntactic processing during reading, as yet very little research has focused on syntactic processing during text reading in children. In two experiments, children and adults read sentences containing a temporary syntactic ambiguity while their eye movements were monitored. In Experiment 1, participants read sentences such as, 'The boy poked the elephant with the long stick/trunk from outside the cage' in which the attachment of a prepositional phrase was manipulated. In Experiment 2, participants read sentences such as, 'I think I'll wear the new skirt I bought tomorrow/yesterday. It's really nice' in which the attachment of an adverbial phrase was manipulated. Results showed that adults and children exhibited similar processing preferences, but that children were delayed relative to adults in their detection of initial syntactic misanalysis. It is concluded that children and adults have the same sentence-parsing mechanism in place, but that it operates with a slightly different time course. In addition, the data support the hypothesis that the visual processing system develops at a different rate than the linguistic processing system in children. PMID:23349807

  7. Human otolith-ocular reflexes during off-vertical axis rotation: effect of frequency on tilt-translation ambiguity and motion sickness

    NASA Technical Reports Server (NTRS)

    Wood, Scott J.; Paloski, W. H. (Principal Investigator)

    2002-01-01

    The purpose of this study was to examine how the modulation of tilt and translation otolith-ocular responses during constant velocity off-vertical axis rotation varies as a function of stimulus frequency. Eighteen human subjects were rotated in darkness about their longitudinal axis 30 degrees off-vertical at stimulus frequencies between 0.05 and 0.8 Hz. The modulation of torsion decreased while the modulation of horizontal slow phase velocity (SPV) increased with increasing frequency. It is inferred that the ambiguity of otolith afferent information is greatest in the frequency region where tilt (torsion) and translational (horizontal SPV) otolith-ocular responses crossover. It is postulated that the previously demonstrated peak in motion sickness susceptibility during linear accelerations around 0.3 Hz is the result of frequency segregation of ambiguous otolith information being inadequate to distinguish between tilt and translation.

  8. Novel ambiguities in the Seiberg-Witten map and the emergent gravity

    NASA Astrophysics Data System (ADS)

    Muthukumar, B.

    2015-01-01

    A homogeneous part of the Seiberg-Witten gauge equivalence relation for gauge fields can lead to solutions that involve matter fields in such a way that the gauge equivalence and the dimensional and index structures are preserved. In particular, we consider scalar fields coupled to U(1) gauge fields. The matter fields appear non-linearly in the map. As an application, we analyze the implication of this ambiguity to emergent gravity at the first order in noncommutative parameter and show that the new ambiguity restores the possibility of conformal coupling of real scalar density field that is coupled non-minimally to the emergent gravity induced by gauge fields a possibility that is strictly not allowed if we consider only the already known ambiguity in the Seiberg-Witten map.

  9. Automated detection of ambiguity in BI-RADS assessment categories in mammography reports.

    PubMed

    Bozkurt, Selen; Rubin, Daniel

    2014-01-01

    An unsolved challenge in biomedical natural language processing (NLP) is detecting ambiguities in the reports that can help physicians to improve report clarity. Our goal was to develop NLP methods to tackle the challenges of identifying ambiguous descriptions of the laterality of BI-RADS Final Assessment Categories in mammography radiology reports. We developed a text processing system that uses a BI-RADS ontology we built as a knowledge source for automatic annotation of the entities in mammography reports relevant to this problem. We used the GATE NLP toolkit and developed customized processing resources for report segmentation, named entity recognition, and detection of mismatches between BI-RADS Final Assessment Categories and mammogram laterality. Our system detected 55 mismatched cases in 190 reports and the accuracy rate was 81%. We conclude that such NLP techniques can detect ambiguities in mammography reports and may reduce discrepancy and variability in reporting. PMID:24743074

  10. Motivation and the Power of Not Giving Up

    MedlinePLUS

    Motivation and the Power of Not Giving Up KidsHealth > Teens > Food & Fitness > Exercise > Motivation and the Power of Not Giving Up Print ... celebrate. It gives you the confidence, courage, and motivation to keep running or doing whatever it is ...

  11. Giving And Receiving Brands As Valentine's Day Gifts

    Microsoft Academic Search

    Peter Clarke; Carmel Herington; Rahim Hussain

    2005-01-01

    This study outlines the relationship between giving and receiving brands as gifts on Valentine's Day. The occasion is a traditional time for declarations of love, adoration or intent that are expressed through a ritual of giving and receiving gifts or greeting cards. The exploratory research here attempts to remedy the shortcomings in the literature concerning brands and gift giving. The

  12. Visual scanning and recognition of Chinese, Caucasian, and racially ambiguous faces: Contributions from bottom-up facial physiognomic information and top-down knowledge of racial categories.

    PubMed

    Wang, Qiandong; Xiao, Naiqi G; Quinn, Paul C; Hu, Chao S; Qian, Miao; Fu, Genyue; Lee, Kang

    2015-02-01

    Recent studies have shown that participants use different eye movement strategies when scanning own- and other-race faces. However, it is unclear (1) whether this effect is related to face recognition performance, and (2) to what extent this effect is influenced by top-down or bottom-up facial information. In the present study, Chinese participants performed a face recognition task with Chinese, Caucasian, and racially ambiguous faces. For the racially ambiguous faces, we led participants to believe that they were viewing either own-race Chinese faces or other-race Caucasian faces. Results showed that (1) Chinese participants scanned the nose of the true Chinese faces more than that of the true Caucasian faces, whereas they scanned the eyes of the Caucasian faces more than those of the Chinese faces; (2) they scanned the eyes, nose, and mouth equally for the ambiguous faces in the Chinese condition compared with those in the Caucasian condition; (3) when recognizing the true Chinese target faces, but not the true target Caucasian faces, the greater the fixation proportion on the nose, the faster the participants correctly recognized these faces. The same was true when racially ambiguous face stimuli were thought to be Chinese faces. These results provide the first evidence to show that (1) visual scanning patterns of faces are related to own-race face recognition response time, and (2) it is bottom-up facial physiognomic information that mainly contributes to face scanning. However, top-down knowledge of racial categories can influence the relationship between face scanning patterns and recognition response time. PMID:25497461

  13. Reconstitution of a defunct glycolytic pathway via recruitment of ambiguous sugar kinases.

    PubMed

    Miller, Brian G; Raines, Ronald T

    2005-08-16

    During a recent investigation of the persistence of substrate ambiguity in contemporary enzymes, we identified three distinct ambiguous sugar kinases embedded within the modern Escherichia coli genome [Miller, B. G., and Raines, R. T. (2004) Biochemistry 43, 6387-6392]. These catalysts are the YajF, YcfX, and NanK polypeptides, all of which possess rudimentary glucokinase activities. Here, we report on the discovery of a fourth bacterial kinase with ambiguous substrate specificity. AlsK phosphorylates the glucose epimer, d-allose, with a k(cat)/K(m) value of 6.5 x 10(4) M(-)(1) s(-)(1). AlsK also phosphorylates d-glucose, with a k(cat)/K(m) value that is 10(5)-fold lower than the k(cat)/K(m) value displayed by native E. coli glucokinase. Overexpression of the alsK gene relieves the auxotrophy of a glucokinase-deficient bacterium, demonstrating that weak enzymatic activities derived from ambiguous catalysts can provide organisms with elaborated metabolic capacities. To explore how ambiguous catalysts are recruited to provide new functions, we placed the glucokinase-deficient bacterium under selection for growth at the expense of glucose. Under these conditions, the bacterium acquires a spontaneous mutation in the putative promoter region of the yajF gene, a locus previously shown to encode a sugar kinase with relaxed substrate specificity. The point mutation regenerates a consensus sigma(70) promoter sequence that leads to a 94-fold increase in the level of yajF expression. This increase provides sufficient glucokinase activity for reconstitution of the defunct glycolytic pathway of the bacterial auxotroph. Our current findings indicate that ambiguous enzymatic activities continue to play an important role in the evolution of new metabolic pathways, and provide insight into the molecular mechanisms that facilitate the recruitment of such catalysts during periods of natural selection. PMID:16086580

  14. Fence - An Efficient Parser with Ambiguity Support for Model-Driven Language Specification

    E-print Network

    Quesada, Luis; Cortijo, Francisco J

    2011-01-01

    Model-based language specification has applications in the implementation of language processors, the design of domain-specific languages, model-driven software development, data integration, text mining, natural language processing, and corpus-based induction of models. Model-based language specification decouples language design from language processing and, unlike traditional grammar-driven approaches, which constrain language designers to specific kinds of grammars, it needs general parser generators able to deal with ambiguities. In this paper, we propose Fence, an efficient bottom-up parsing algorithm with lexical and syntactic ambiguity support that enables the use of model-based language specification in practice.

  15. 1 10?16 frequency transfer by GPS PPP with integer ambiguity resolution

    NASA Astrophysics Data System (ADS)

    Petit, Grard; Kanj, Amale; Loyer, Sylvain; Delporte, Jrme; Mercier, Flavien; Perosanz, Flix

    2015-04-01

    For many years, the time community has been using the precise point positioning (PPP) technique which uses GPS phase and code observations to compute time and frequency links. However, progress in atomic clocks implies that the performance of PPP frequency comparisons is a limiting factor in comparing the best frequency standards. We show that a PPP technique where the integer nature of phase ambiguities is preserved consitutes significant improvement of the classical use of floating ambiguities. We demonstrate that this integer-PPP technique allows frequency comparisons with 1? ?10?16 accuracy in a few days and can be readily operated with existing products.

  16. Efficient decomposition of cosmic microwave background polarization maps into pure E, pure B, and ambiguous components

    SciTech Connect

    Bunn, Emory F. [Physics Department, University of Richmond, Richmond, Virginia 23173 (United States)

    2011-04-15

    Separation of the B component of a cosmic microwave background (CMB) polarization map from the much larger E component is an essential step in CMB polarimetry. For a map with incomplete sky coverage, this separation is necessarily hampered by the presence of ambiguous modes which could be either E or B modes. I present an efficient pixel-space algorithm for removing the ambiguous modes and separating the map into pure E and B components. The method, which works for arbitrary geometries, does not involve generating a complete basis of such modes and scales the cube of the number of pixels on the boundary of the map.

  17. 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

  18. Giving and taking: Representational building blocks of active resource-transfer events in human infants.

    PubMed

    Tatone, Denis; Geraci, Alessandra; Csibra, Gergely

    2015-04-01

    Active resource transfer is a pervasive and distinctive feature of human sociality. We hypothesized that humans possess an action schema of giving specific for representing social interactions based on material exchange, and specified the set of necessary assumptions about giving events that this action schema should be equipped with. We tested this proposal by investigating how 12-month-old infants interpret abstract resource-transfer events. Across eight looking-time studies using a violation-of-expectation paradigm we found that infants were able to distinguish between kinematically identical giving and taking actions. Despite the surface similarity between these two actions, only giving was represented as an object-mediated social interaction. While we found no evidence that infants expected the target of a giving or taking action to reciprocate, the present results suggest that infants interpret giving as an inherently social action, which they can possibly use to map social relations via observing resource-transfer episodes. PMID:25614012

  19. Giving the influenza jab: a review of the law.

    PubMed

    Griffiths, Richard

    2004-10-01

    District nursing sister June Harris recently completed the administration of 30 'flu jabs to frail older residents of a local care home. June encountered a number of problems when administering the vaccinations. Relatives of five residents with advanced dementia did not want them to have the injection, mainly because they had heard that it would give the recipient the 'flu. An 85-year-old resident has complained that while she agreed to have a 'flu jab it now appears she also had a pneumococcal vaccination as well that no one told her about. More seriously, June has recently heard that one resident is in hospital having contracted Guillian-Barre Syndrome as a result of the vaccination. June remembers that this reluctant resident specifically asked if the 'flu jab would leave her paralysed and June had laughingly replied that she had not paralysed anyone to date. The residents and their families are now threatening legal action. PMID:15577723

  20. Neural predictors of giving in to temptation in daily life.

    PubMed

    Lopez, Richard B; Hofmann, Wilhelm; Wagner, Dylan D; Kelley, William M; Heatherton, Todd F

    2014-07-01

    The ability to control desires, whether for food, sex, or drugs, enables people to function successfully within society. Yet, in tempting situations, strong impulses often result in self-control failure. Although many triggers of self-control failure have been identified, the question remains as to why some individuals are more likely than others to give in to temptation. In this study, we combined functional neuroimaging and experience sampling to determine if there are brain markers that predict whether people act on their food desires in daily life. We examined food-cue-related activity in the nucleus accumbens (NAcc), as well as activity associated with response inhibition in the inferior frontal gyrus (IFG). Greater NAcc activity was associated with greater likelihood of self-control failures, whereas IFG activity supported successful resistance to temptations. These findings demonstrate an important role for the neural mechanisms underlying desire and self-control in people's real-world experiences of temptations. PMID:24789842

  1. A Hierarchical Linear Modeling Analysis of Working Memory and Implicit Prosody in the Resolution of Adjunct Attachment Ambiguity

    ERIC Educational Resources Information Center

    Traxler, Matthew J.

    2009-01-01

    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

  2. Docking of Protein-Protein Complexes on the Basis of Highly Ambiguous Intermolecular Distance Restraints Derived from

    E-print Network

    Clore, G. Marius

    Docking of Protein-Protein Complexes on the Basis of Highly Ambiguous Intermolecular Distance ambiguous, intermolecular distance restraints (comprising between 400 and 3000 individual distances) to avoid expansion at the protein-protein interface, and a torsion angle database potential of mean force

  3. Removal of ordering ambiguity for a class of position dependent mass quantum systems with an application to the quadratic Linard type nonlinear oscillators

    E-print Network

    V. Chithiika Ruby; V. K. Chandrasekar; M Senthilvelan; M. Lakshmanan

    2014-11-26

    We consider the problem of removal of ordering ambiguity in position dependent mass quantum systems characterized by a generalized position dependent mass Hamiltonian which generalizes a number of Hermitian as well as non-Hermitian ordered forms of the Hamiltonian. We implement point canonical transformation method to map one-dimensional time-independent position dependent mass Schr$\\"{o}$dinger equation endowed with potentials onto constant mass counterparts which are considered to be exactly solvable. We observe that a class of mass functions and the corresponding potentials give rise to solutions that do not depend on any particular ordering, leading to the removal of ambiguity in it. In this case, it is imperative that the ordering is Hermitian. For non-Hermitian ordering we show that the class of systems can also be exactly solvable and are also shown to be iso-spectral using suitable similarity transformations. We also discuss the normalization of the eigenfunctions obtained from both Hermitian and non-Hermitian orderings. We illustrate the technique with the quadratic Li$\\'{e}$nard type nonlinear oscillators, which admit position dependent mass Hamiltonians.

  4. Removal of ordering ambiguity for a class of position dependent mass quantum systems with an application to the quadratic Linard type nonlinear oscillators

    NASA Astrophysics Data System (ADS)

    Chithiika Ruby, V.; Chandrasekar, V. K.; Senthilvelan, M.; Lakshmanan, M.

    2015-01-01

    We consider the problem of removal of ordering ambiguity in position dependent mass quantum systems characterized by a generalized position dependent mass Hamiltonian which generalizes a number of Hermitian as well as non-Hermitian ordered forms of the Hamiltonian. We implement point canonical transformation method to map one-dimensional time-independent position dependent mass Schrdinger equation endowed with potentials onto constant mass counterparts which are considered to be exactly solvable. We observe that a class of mass functions and the corresponding potentials give rise to solutions that do not depend on any particular ordering, leading to the removal of ambiguity in it. In this case, it is imperative that the ordering is Hermitian. For non-Hermitian ordering, we show that the class of systems can also be exactly solvable and is also shown to be iso-spectral using suitable similarity transformations. We also discuss the normalization of the eigenfunctions obtained from both Hermitian and non-Hermitian orderings. We illustrate the technique with the quadratic Linard type nonlinear oscillators, which admit position dependent mass Hamiltonians.

  5. Engineering Objects for Collaboration: Strategies of Ambiguity and Clarity at Knowledge Boundaries

    ERIC Educational Resources Information Center

    Barley, William C.; Leonardi, Paul M.; Bailey, Diane E.

    2012-01-01

    Prior research suggests that boundary objects gain meaning through group interaction. Drawing from the literature on strategic ambiguity, we explore the possibility that individuals strategically create potential boundary objects in an attempt to shape the meanings that groups develop. From ethnographic observations of automotive engineers, we

  6. Pure science or policy involvement? Ambiguous boundary-work for Swedish carbon cycle science

    E-print Network

    Colorado at Boulder, University of

    Pure science or policy involvement? Ambiguous boundary-work for Swedish carbon cycle science Eva Lo). In this paper, I explore how this claim relates to basic carbon cycle research, conducted in traditional in 1997, carbon cycle scientists have worked in tandem with government negotiators in order to come up

  7. Concern-Focused Evaluation for Ambiguous and Conflicting Policies: An Approach from the Environmental Field

    ERIC Educational Resources Information Center

    Mermet, Laurent; Bille, Raphael; Leroy, Maya

    2010-01-01

    Environment and sustainable development show how policies are becoming ever more complex and ambiguous. This trend calls for new evaluation approaches. They need to be more clearly focused on specific, explicit concerns. They must be driven by a strategic concept of use to overcome the vulnerability to manipulation of many integrative, essentially

  8. AmbiPack: A Systematic Algorithm for Packing of Macromolecular Structures With Ambiguous

    E-print Network

    Lozano-Perez, Tomas

    method to solve the packing and the assignment problems simultaneously given rigid monomer structuresAmbiPack: A Systematic Algorithm for Packing of Macromolecular Structures With Ambiguous Distance of multimers presents interesting new challenges. The structure(s) of the individual monomers must be found

  9. Ambiguous sound elements contribute differently to auditory object identity and object location

    E-print Network

    Lee, Adrian KC

    narrowband noise). Spatial cues in the target pulled the perceived vowel location even when the target containing an ambiguous sound element (target) that logically could belong to either of two objects: a slowly was spectrally shaped so that it was heard as a vowel. The "target", a 500-Hz tone presented simultaneously

  10. Reconstitution of a Defunct Glycolytic Pathway via Recruitment of Ambiguous Sugar Kinases

    E-print Network

    Raines, Ronald T.

    K polypeptides, all of which possess rudimentary glucokinase activities. Here, we report on the discovery such as the acquisition of antibiotic resistance by pathogenic bacteria, the bioremediation of man-made pollutants by soil the genome of a common bacterium, we recently identified three distinct polypeptides that possess ambiguous

  11. Reading Sentences with a Late Closure Ambiguity: Does Semantic Information Help?

    ERIC Educational Resources Information Center

    Lipka, Sigrid

    2002-01-01

    Three studies are reported that addressed methodological problems in Stowe's (1989) study, which reported that semantic information eliminates garden paths in sentences with direct object versus subject ambiguity, such as in "Even before the police stopped the driver was frightened." Findings support a sentence processing system relying on

  12. The Functional Organisation of the Fronto-Temporal Language System: Evidence from Syntactic and Semantic Ambiguity

    ERIC Educational Resources Information Center

    Rodd, Jennifer M.; Longe, Olivia A.; Randall, Billi; Tyler, Lorraine K.

    2010-01-01

    Spoken language comprehension is known to involve a large left-dominant network of fronto-temporal brain regions, but there is still little consensus about how the syntactic and semantic aspects of language are processed within this network. In an fMRI study, volunteers heard spoken sentences that contained either syntactic or semantic ambiguities

  13. Imaginary Companions and Young Children's Responses to Ambiguous Auditory Stimuli: Implications for Typical and Atypical Development

    ERIC Educational Resources Information Center

    Fernyhough, Charles; Bland, Kirsten; Meins, Elizabeth; Coltheart, Max

    2007-01-01

    Background: Previous research has reported a link between imaginary companions (ICs) in middle childhood and the perception of verbal material in ambiguous auditory stimuli. These findings have been interpreted in terms of commonalities in the cognitive processes underlying children's engagement with ICs and adults' reporting of imaginary verbal

  14. Preferences for Travel Time under Risk and Ambiguity: Implications in Path Selection and Network Equilibrium

    E-print Network

    Sun, Defeng

    Preferences for Travel Time under Risk and Ambiguity: Implications in Path Selection and Network the preferences for uncertain travel time in which the probability distribu- tion may not be fully characterized. In evaluating an uncertain travel time, we explicitly distinguish between risk, where probability distribution

  15. Newcomer Immigrant Adolescents and Ambiguous Discrimination: The Role of Cognitive Appraisal

    ERIC Educational Resources Information Center

    Patel, Sita G.; Tabb, Kevin M.; Strambler, Michael J.; Eltareb, Fazia

    2015-01-01

    Cognitive appraisal has been shown to mediate the relationship between stressors and internalizing symptoms, but not among newcomer immigrant youth facing ambiguous discrimination. Using a mixed-methods design with a sample of newcomer adolescents from African, Arab, Asian, Caribbean, European, and Latin American countries, this study measured the

  16. Tinkering with Material Resources: Operating under Ambiguous Conditions in Rock Construction Work

    ERIC Educational Resources Information Center

    Styhre, Alexander

    2009-01-01

    Purpose: Ethnographic studies of, for instance, laboratory work show that practices never reach a full closure but are always open to contingencies and ambiguities, making it possible to accommodate new empirical findings. The aim of the paper is to demonstrate that this is true also for less "high-brow" work in, for example, the construction

  17. (E)pistemological Awareness, Instantiation of Methods, and Uninformed Methodological Ambiguity in Qualitative Research Projects

    Microsoft Academic Search

    Mirka Koro-Ljungberg; Diane Yendol-Hoppey; Jason Jude Smith; Sharon B. Hayes

    2009-01-01

    This article explores epistemological awareness and instantiation of methods, as well as uninformed ambiguity, in qualitative methodological decision making and research reporting. The authors argue that efforts should be made to make the research process, epistemologies, values, methodological decision points, and argumentative logic open, accessible, and visible for audiences. To these ends, they discuss two ways of conceptualizing the role

  18. The Professional Negotiator: Role Conflict, Role Ambiguity and Motivation To Work.

    ERIC Educational Resources Information Center

    Medford, Robert E.; Miskel, Cecil

    The investigation examined the relationship among role conflict, role ambiguity, and motivation to work of teacher-negotiators. The theoretical rationale for the study was formulated from the finding of Walton and McKersie, Deutsch, Vidmar and McGrath, and Blum concerning the negotiator's conflict with his adversary, his dependence on his

  19. Supervisor Relationships, Teamwork, Role Ambiguity and Discretionary Power: Nurses in Australia and the United Kingdom

    Microsoft Academic Search

    Yvonne Brunetto; Rodney Farr-Wharton; Kate Shacklock; Fiona Robson

    2012-01-01

    This paper reports comparative research comparing the relationship between supervisor-subordinate relationships, teamwork, role ambiguity and discretionary power for nurses working in public and private sector hospitals in Australia and the UK. The findings indicate that the four factors accounted for approximately a quarter of the variance for nurses in the UK and almost a fifth of the variance for nurses

  20. The ambiguous boundary between genes and pseudogenes: the dead rise up, or do they?

    Microsoft Academic Search

    Deyou Zheng; Mark B. Gerstein

    2007-01-01

    Pseudogenes have long been considered to be 'dead', nonfunctional by-products of genome evolution. How- ever, several lines of evidence now show that some pseudogenes are transcriptionally 'alive', and a few might even have biochemical roles. Therefore, the boundary between genes (often considered to be 'liv- ing') and pseudogenes (often considered to be 'dead') might be ambiguous and difficult to define.

  1. Enhancing Preschoolers' Understanding of Ambiguity in Communication: A Training Study on Misunderstandings

    ERIC Educational Resources Information Center

    Carmiol, Ana M.; Vinden, Penelope G.

    2013-01-01

    Understanding knowledge acquisition involves a comprehension of the relationship between a person's access to relevant information and that person's subsequent knowledge. This report investigates how preschoolers improve in their ability to evaluate the effects of two distinct types of messages--ambiguous and informative--on a listener's

  2. The indexing ambiguity in serial femtosecond crystallography (SFX) resolved using an expectation maximization algorithm

    PubMed Central

    Liu, Haiguang; Spence, John C.H.

    2014-01-01

    Crystallographic auto-indexing algorithms provide crystal orientations and unit-cell parameters and assign Miller indices based on the geometric relations between the Bragg peaks observed in diffraction patterns. However, if the Bravais symmetry is higher than the space-group symmetry, there will be multiple indexing options that are geometrically equivalent, and hence many ways to merge diffraction intensities from protein nanocrystals. Structure factor magnitudes from full reflections are required to resolve this ambiguity but only partial reflections are available from each XFEL shot, which must be merged to obtain full reflections from these stills. To resolve this chicken-and-egg problem, an expectation maximization algorithm is described that iteratively constructs a model from the intensities recorded in the diffraction patterns as the indexing ambiguity is being resolved. The reconstructed model is then used to guide the resolution of the indexing ambiguity as feedback for the next iteration. Using both simulated and experimental data collected at an X-ray laser for photosystem I in the P63 space group (which supports a merohedral twinning indexing ambiguity), the method is validated. PMID:25485120

  3. (E)pistemological Awareness, Instantiation of Methods, and Uninformed Methodological Ambiguity in Qualitative Research Projects

    ERIC Educational Resources Information Center

    Koro-Ljungberg, Mirka; Yendol-Hoppey, Diane; Smith, Jason Jude; Hayes, Sharon B.

    2009-01-01

    This article explores epistemological awareness and instantiation of methods, as well as uninformed ambiguity, in qualitative methodological decision making and research reporting. The authors argue that efforts should be made to make the research process, epistemologies, values, methodological decision points, and argumentative logic open,

  4. Using Semantic Ambiguity Instruction to Improve Third Graders' Metalinguistic Awareness and Reading Comprehension: An Experimental Study

    ERIC Educational Resources Information Center

    Zipke, Marcy; Ehri, Linnea C.; Cairns, Helen Smith

    2009-01-01

    An experiment examined whether metalinguistic awareness involving the detection of semantic ambiguity can be taught, and whether this instruction improves students' reading comprehension. Lower SES third graders from a variety of cultural backgrounds (M = 8 yr. 7 mo., N = 46) were randomly assigned to treatment and control groups. Those receiving

  5. Capstone and Building Block: Helping Students Manage Ambiguity about their Futures through Writing

    ERIC Educational Resources Information Center

    Love, Brad; Mackert, Michael

    2013-01-01

    Encouraging students to engage with principles and ideas is one way to address ambiguity with consistent, effective approaches in situations made up of "gray area." This includes the looming post-college world where students may be unsure about choosing between job offers, geographic locations, or even communication fields. Such

  6. Effects of work load, role ambiguity, and Type A personality on anxiety, depression, and heart rate

    Microsoft Academic Search

    Robert D. Caplan; Kenneth W. Jones

    1975-01-01

    Studied Type A personality (hard driving, persistent, involved in work) as a conditioner of the effects of quantitative work load and role ambiguity (stresses) on anxiety, depression, resentment, and heart rate (strains) among 73 male users (mean age, 23 yrs) of a university computer system that was approaching a 23-day shutdown. Each respondent was his own control. Stress, personality, and

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

    ERIC Educational Resources Information Center

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

    2013-01-01

    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

  8. Ambiguity and Relatedness Effects in Semantic Tasks: Are They Due to Semantic Coding?

    ERIC Educational Resources Information Center

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

    2006-01-01

    According to parallel distributed processing (PDP) models of visual word recognition, the speed of semantic coding is modulated by the nature of the orthographic-to-semantic mappings. Consistent with this idea, an ambiguity disadvantage and a relatedness-of-meaning (ROM) advantage have been reported in some word recognition tasks in which semantic

  9. Cognate and Word Class Ambiguity Effects in Noun and Verb Processing

    ERIC Educational Resources Information Center

    Bultena, Sybrine; Dijkstra, Ton; van Hell, Janet G.

    2013-01-01

    This study examined how noun and verb processing in bilingual visual word recognition are affected by within and between-language overlap. We investigated how word class ambiguous noun and verb cognates are processed by bilinguals, to see if co-activation of overlapping word forms between languages benefits from additional overlap within a

  10. Young Word Learners' Interpretations of Words and Symbolic Gestures within the Context of Ambiguous Reference

    ERIC Educational Resources Information Center

    Suanda, Sumarga H.; Namy, Laura L.

    2013-01-01

    Early in development, many word-learning phenomena generalize to symbolic gestures. The current study explored whether children avoid lexical overlap in the gestural modality, as they do in the verbal modality, within the context of ambiguous reference. Eighteen-month-olds' interpretations of words and symbolic gestures in a symbol-disambiguation

  11. Not All Ambiguous Words Are Created Equal: An EEG Investigation of Homonymy and Polysemy

    ERIC Educational Resources Information Center

    Klepousniotou, Ekaterini; Pike, G. Bruce; Steinhauer, Karsten; Gracco, Vincent

    2012-01-01

    Event-related potentials (ERPs) were used to investigate the time-course of meaning activation of different types of ambiguous words. Unbalanced homonymous ("pen"), balanced homonymous ("panel"), metaphorically polysemous ("lip"), and metonymically polysemous words ("rabbit") were used in a visual single-word priming delayed lexical decision task.

  12. Ambiguities of the CPT-even aether-like Lorentz-breaking term at finite temperature

    NASA Astrophysics Data System (ADS)

    Mariz, T.; Nascimento, J. R.; Petrov, A. Yu.; Serafim, W.

    2014-08-01

    In this paper, we consider the finite-temperature behavior of the CPT-even aether-like Lorentz-breaking term in the extended Lorentz-breaking QED and demonstrate that its ambiguities, whose presence has been shown earlier in the zero-temperature case, stay also at a finite temperature.

  13. Sentence Context and Meaning Frequency Effects in Children's Processing of Ambiguous Words.

    ERIC Educational Resources Information Center

    Simpson, Greg B.; And Others

    1994-01-01

    Investigates context effects for words with more than one meaning. Finds that younger children (third graders) were more sensitive to the sentence context in which an ambiguous word appears, whereas the processing of older children (sixth graders) was determined more by the relative frequencies of the word meanings. (RS)

  14. Effects of representational distance between meanings on the neural correlates of semantic ambiguity.

    PubMed

    Grindrod, Christopher M; Garnett, Emily O; Malyutina, Svetlana; den Ouden, Dirk B

    2014-12-01

    Psycholinguistic research demonstrates that representational distance between meanings influences recognition of ambiguous words. Our goal was to investigate whether the neural correlates of ambiguity are also modulated by representational distance as a function of syntactic similarity (i.e., grammatical class) and meaning dominance. In an event-related fMRI experiment, participants completed a visual lexical decision task that included balanced and unbalanced noun-noun and noun-verb homonyms, unambiguous words, and nonwords. Syntactic similarity effects were observed in left inferior frontal regions, with greater activation for noun-verb than noun-noun homonyms. Meaning dominance effects were observed in left middle and superior temporal regions, with greater activation for balanced than unbalanced homonyms. These findings indicate that the behavioral cost associated with processing ambiguous word meanings, modulated by syntactic similarity and meaning dominance, is reflected in the neural systems underlying ambiguity processing, as frontal and temporal regions are recruited by increased competition as a function of representational distance. PMID:25463814

  15. An Ambiguous, Contested Terrain: Governance Models for a New South African Education System

    ERIC Educational Resources Information Center

    Weber, Everard

    2002-01-01

    This paper reviews the development of education governance in South Africa during the 1990s. It outlines ambiguities within and between competing policies, tracing the historical trajectory and explaining its outcome. Apartheid governance, the attempts to reform it, policy options originating within the anti-apartheid movement, and the law passed

  16. Method and apparatus for reducing range ambiguity in synthetic aperture radar

    DOEpatents

    Kare, Jordin T. (San Ramon, CA)

    1999-10-26

    A modified Synthetic Aperture Radar (SAR) system with reduced sensitivity to range ambiguities, and which uses secondary receiver channels to detect the range ambiguous signals and subtract them from the signal received by the main channel. Both desired and range ambiguous signals are detected by a main receiver and by one or more identical secondary receivers. All receivers are connected to a common antenna with two or more feed systems offset in elevation (e.g., a reflector antenna with multiple feed horns or a phased array with multiple phase shift networks. The secondary receiver output(s) is (are) then subtracted from the main receiver output in such a way as to cancel the ambiguous signals while only slightly attenuating the desired signal and slightly increasing the noise in the main channel, and thus does not significantly affect the desired signal. This subtraction may be done in real time, or the outputs of the receivers may be recorded separately and combined during signal processing.

  17. Miniature Interferometer Terminals for Earth Surveying: Ambiguity And Multipath with Global Positioning System

    Microsoft Academic Search

    Charles C. Counselman; Sergei A. Gourevitch

    1981-01-01

    With the recent launching of several satellites of the global positioning system (GPS), a variety of schemes based on radio interferometry have been proposed for the accurate determination of relative positions of receiving terminals on the ground. Provided that the integer-cycle ambiguities of the interferometric phase observations can be correctly resolved, the baseline vector extending from the antenna of one

  18. Dealing With Ambiguous and Fluctuating Requirements of Embedded System Development: A CaseStudy

    Microsoft Academic Search

    Wolfgang Molnar; Joe Nandhakumar

    2008-01-01

    This paper presents the findings of a case study that investigates how developers and managers deal with ambiguous and fluctuating requirements during an embedded system development in a structured process management environment. In particular, this paper focuses on improvisation and bricolage actions as a coping strategy by software developers and managers. This research adopts an interpretive approach that involves the

  19. Why is "that"? Structural Prediction and Ambiguity Resolution in a Very Large Corpus of English Sentences

    ERIC Educational Resources Information Center

    Roland, Douglas; Elman, Jeffrey L.; Ferreira, Victor S.

    2006-01-01

    Previous psycholinguistic research has shown that a variety of contextual factors can influence the interpretation of syntactically ambiguous structures, but psycholinguistic experimentation inherently does not allow for the investigation of the role that these factors play in natural (uncontrolled) language use. We use regression modeling in

  20. Main Verb Versus Reduced Relative Clause Ambiguity Resolution in L2 Sentence Processing.

    ERIC Educational Resources Information Center

    Juffs, Alan

    1998-01-01

    Investigated how adult learners of English-as-a-Second- Language (ESL) process sentences containing verbs that are temporarily ambiguous in interpretation between a main verb and a reduced relative clause. Seventeen Chinese, 17 Korean or Japanese, and 17 Romance learners with advanced ESL proficiency and a comparison group of 17 monolingual native