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Sample records for give ambiguous results

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

    PubMed Central

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

    2015-01-01

    Many variants that could be returned from genome sequencing may be perceived as ambiguous—lacking reliability, credibility, or adequacy. Little is known about how perceived ambiguity influences thoughts about sequencing results. Participants (n=494) in an NIH genome sequencing study completed a baseline survey before sequencing results were available. We examined how perceived ambiguity regarding sequencing results and individual differences in medical ambiguity aversion and tolerance for uncertainty were associated with cognitions and intentions concerning sequencing results. Perceiving sequencing results as more ambiguous was associated with less favorable cognitions about results and lower intentions to learn and share results. Among participants low in tolerance for uncertainty or optimism, greater perceived ambiguity was associated with lower intentions to learn results for non-medically actionable diseases; medical ambiguity aversion did not moderate any associations. Results are consistent with the phenomenon of “ambiguity aversion” and may influence whether people learn and communicate genomic information. PMID:26003053

  2. [Should we give the examination results to the patients?].

    PubMed

    Tondeur, M; Ham, H

    2000-04-01

    Immediately after medical imaging procedures, patients often ask for the results of their examination. Such a request is very uncomfortable for the physician performing the examination, who usually does not know the whole medical file, the psychological status of the patient, how he is informed about his illness, etc. By the means of a questionnaire we asked belgian nuclear medicine physicians about the frequency of such situations and about their practical attitude. 204 questionnaires were sent; we received 119 answers (58%) after a 6 weeks delay. In more than 85% of the cases, this situation occurs regularly, and more than 50% of the participating physicians encounter the problem in more than 20% of the cases. Less than 10% of the participating physicians never give any result to the patient asking for it, while more than 20% always give it. Most of the physicians takes into account the clinical situation of the patient. Unfortunately, the official guidelines do not help to clarify the situation. This work confirms that physicians who perform diagnostic procedures frequently encounter difficulties in patients information. It would be necessary that all people who are concerned by this problem collaborate in order to define a clear and accurate attitude which would be easily applicable in our daily clinical practice. PMID:10829602

  3. Real-time PPP with undifferenced integer ambiguity resolution, experimental results

    NASA Astrophysics Data System (ADS)

    Laurichesse, Denis; Mercier, Flavien

    2010-05-01

    A method to solve the GPS zero-difference measurement equations with integer ambiguities has been recently introduced at CNES. When the method is applied to data from a global network of GPS receivers it provides a consistent set of satellite orbits and clocks, which have an ‘integer' property: phase residuals for any receiver computed using these orbits and clocks easily reveal integer ambiguities. The presentation focuses on the application of this novel approach to the computation of real-time orbits and clocks for the GPS constellation, and the benefit of using these products for real-time Precise Point Positioning (PPP) with integer ambiguity fixing of user receivers. In this method, real-time corrections to extrapolated IGS IGU orbits are estimated at the same time as all other relevant parameters by a Kalman filter which processes measurements from a world-wide stations network. The filter performs zero-difference ambiguity fixing in real-time. Two results are presented; the first with one month of raw data taken from the IGS, the second with raw data taken from the Internet in real-time using the NTRIP protocol. Relative to IGS final orbits, the 3-D precision of the real-time orbits is about 3 cm RMS. When these constellation orbits and clocks are used to perform real-time PPP for receivers outside of the reference network, the horizontal precision obtained using zero-difference integer ambiguity fixing is close to 1 cm RMS. This is about one order of magnitude better than standard solutions, which rely upon floating ambiguity fixing, close to the precision of RTK. We present several ‘site survey' type real-time experiments conducted at CNES that confirm these results. Advantages and drawbacks of this new integer-PPP method with respect to RTK are outlined. These topics include mainly the time to convergence, the baselines size and the associated precision. Some specific applications of this new method, especially those that cannot be obtained using a standard RTK method are proposed. Finally, ongoing and future work conducted at CNES on real-time applications is outlined. This work concerns mainly the development of a real-time integer PPP demonstrator. The goal and architecture of this demonstrator is presented, as well as the current development state and some preliminary results.

  4. Study Finds Charter Networks Give No Clear Edge on Results

    ERIC Educational Resources Information Center

    Shah, Nirvi

    2011-01-01

    The author reports on a national study of middle school students in 40 charter networks which finds that, when it comes to having an impact on student achievement, results vary and, overall, charter students do not learn dramatically more than their counterparts in regular public schools. The findings from the research group Mathematica and the…

  5. 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

  6. 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

  7. Reducing values: dinitrosalicylate gives over-oxidation and invalid results whereas copper bicinchoninate gives no over-oxidation and valid results.

    PubMed

    McIntyre, Amanda P; Mukerjea, Rupendra; Robyt, John F

    2013-10-18

    A comparative study was made between two carbohydrate reducing value methods, a relatively old, highly alkaline, 3,5-dinitrosalicylic acid (DNSA) method and a relatively newer, low alkaline (pH 10.5), copper bicinchoninate (CuBic) method. Reducing values for a series of equimolar amounts of maltose-maltohexaose, isomaltose-isomaltohexaose, and cellobiose-cellohexaose were compared by the two methods. The DNSA method gave over-oxidation for equimolar amounts of all three of the oligosaccharide series. The amount of oxidation increased as the sizes of the oligosaccharides increased, giving inflated, inaccurate reducing values. The CuBic method gave constant reducing values, for equimolar amounts of the oligosaccharides, indicating that there was no over-oxidation, as the sizes of the oligosaccharides were increased. The two methods were used to determine the number average molecular weights (MWn) for six polysaccharides. The DNSA method was not able to determine the MWn for any of the polysaccharides tested due to the low sensitivity of the method, compared with the CuBic method that did not give over-oxidation and gave reasonable MWn values for all six of the polysaccharides tested. PMID:24021436

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

    PubMed Central

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

    2014-01-01

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

  9. Divided loyalties and ambiguous relationships.

    PubMed

    Toulmin, S

    1986-01-01

    The author argues that conflicts of obligation may, but need not, give rise to issues of divided loyalties. Given this, the question then becomes under what circumstances and conditions a simple internal conflict may escalate into the problem of divided loyalties or fiduciary ambiguities. After discussing conflicts of obligation, it is asserted that loyalties are divided only when the demands of the various relationships involved are irreconcilable. As this is an extreme, the major problematic issues fall, then, in between, on multiple loyalties and ambiguous loyalties. How and where multiple loyalties arise, and under what conditions they may become ambiguous loyalties lead to the recognition that moral problems are created by leaving in ambiguity things about the relationships involved that would be better sorted out. Finally the author looks at situations in which physicians are systematically exposed to irresoluble ambiguity. PMID:3798158

  10. The Ambiguity in Immunology

    PubMed Central

    Barnaba, Vincenzo; Paroli, Marino; Piconese, Silvia

    2012-01-01

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

  11. Fermionic entanglement ambiguity in noninertial frames

    SciTech Connect

    Montero, Miguel; Martin-Martinez, Eduardo

    2011-06-15

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

  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: 5–8, mean: 6.8). In conclusion, we demonstrated that repeated freezing/thawing of processed semen using our rapid freezing method gave better results than standard slow programmable freezing. This method can help maximize the usage of precious cryopreserved sperm samples in assisted reproduction technology. PMID:23064685

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

    NASA Astrophysics Data System (ADS)

    Holloway, Stephen

    1997-03-01

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

  14. 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.

  15. Transcriptional errors and ambiguity resulting from the presence of 1,N6-ethenoadenosine or 3,N4-ethenocytidine in polyribonucleotides.

    PubMed Central

    Spengler, S; Singer, B

    1981-01-01

    1,N6-Ethenoadenosine (epsilon A) and 3,N4-Ethenocytidine (epsilon C) in copolymers with unmodified nucleosides were transcribed using DNA-dependent RNA polymerase in the presence of Mn2+. Nearest neighbor analysis of the products showed that epsilon A directed incorporation of A much greater than U greater than C while epsilon C directed the incorporation of U greater than or equal to A much greater than C Neither directed G into the complementary polymer. Such misincorporations resulting from epsilon A and epsilon C, compounds that are formed in vivo by the carcinogen vinyl chloride, may have a biological role as promutagens. PMID:7208355

  16. Vignettes of Ambiguity

    ERIC Educational Resources Information Center

    Gotz, Ignacio L.

    2010-01-01

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

  17. Processing Coordination Ambiguity

    ERIC Educational Resources Information Center

    Engelhardt, Paul E.; Ferreira, Fernanda

    2010-01-01

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

  18. 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

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

    PubMed Central

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

    2015-01-01

    HIGHLIGHTS We use a simple gambles design in an fMRI study to compare two conditions: ambiguity and conflict.Participants were more conflict averse than ambiguity averse.Ambiguity aversion did not correlate with conflict aversion.Activation in the medial prefrontal cortex correlated with ambiguity level and ambiguity aversion.Activation in the ventral striatum correlated with conflict level and conflict aversion. Studies of decision making under uncertainty generally focus on imprecise information about outcome probabilities (“ambiguity”). It is not clear, however, whether conflicting information about outcome probabilities affects decision making in the same manner as ambiguity does. Here we combine functional magnetic resonance imaging (fMRI) and a simple gamble design to study this question. In this design the levels of ambiguity and conflict are parametrically varied, and ambiguity and conflict gambles are matched on expected value. Behaviorally, participants avoided conflict more than ambiguity, and attitudes toward ambiguity and conflict did not correlate across participants. Neurally, regional brain activation was differentially modulated by ambiguity level and aversion to ambiguity and by conflict level and aversion to conflict. Activation in the medial prefrontal cortex was correlated with the level of ambiguity and with ambiguity aversion, whereas activation in the ventral striatum was correlated with the level of conflict and with conflict aversion. These novel results indicate that decision makers process imprecise and conflicting information differently, a finding that has important implications for basic and clinical research. PMID:26640434

  20. Selfless giving.

    PubMed

    Bartels, Daniel M; Kvaran, Trevor; Nichols, Shaun

    2013-11-01

    In four studies, we show that people who anticipate more personal change over time give more to others. We measure and manipulate participants' beliefs in the persistence of the defining psychological features of a person (e.g., his or her beliefs, values, and life goals) and measure generosity, finding support for the hypothesis in three studies using incentive-compatible charitable donation decisions and one involving hypothetical choices about sharing with loved ones. PMID:23973466

  1. 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.

  2. Ambiguity noise analysis of a SAR system

    NASA Astrophysics Data System (ADS)

    Tian, Haishan; Chang, Wenge; Li, Xiangyang

    2015-12-01

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

  3. Resolution of quantifier scope ambiguities.

    PubMed

    Kurtzman, H S; MacDonald, M C

    1993-09-01

    Various processing principles have been suggested to be governing the resolution of quantifier scope ambiguities in sentences such as Every kid climbed a tree. This paper investigates structural principles, that is, those which refer to the syntactic or semantic positions of the quantified phrases. To test these principles, the preferred interpretations for three grammatical constructions were determined in a task in which participants made speeded judgments of whether a sentence following a doubly quantified sentence was a reasonable discourse continuation of the quantified sentence. The observed preferences cannot be explained by any single structural principle, but point instead to the interaction of several principles. Contrary to many proposals, there is little or no effect of a principle that assigns scope according to the linear order of the phrases. The interaction of principles suggests that alternative interpretations of the ambiguity may be initially considered in parallel, followed by selection of the single interpretation that best satisfies the principles. These results are discussed in relation to theories of ambiguity resolution at other levels of linguistic representation. PMID:8269698

  4. Processing ambiguous verbs: evidence from eye movements.

    PubMed

    Pickering, M J; Frisson, S

    2001-03-01

    In 2 eye-tracking experiments, participants read verbs that had 2 (unrelated) meanings or 2 (related) senses in contexts that disambiguated before or after the verb, to the dominant or subordinate interpretation. A 3rd experiment used unambiguous verbs. The results indicated that the language processor used information about context in the early stages of resolving meaning ambiguities but only during integration for sense ambiguities. Effects of preference were delayed for both types of verbs. The results contrast with findings concerning the processing of nouns (e.g., K. Rayner & S. A. Duffy, 1986). For meaning ambiguities, the authors argue that delays in resolution allow both meanings to reach a high level of activation, thus reducing effects of frequency. For sense ambiguities, the authors argue that the processor does not access multiple senses but activates one underspecified meaning and uses context to home in on the appropriate sense. PMID:11294449

  5. 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

  6. The Ambiguous Dying Syndrome

    ERIC Educational Resources Information Center

    Bern-Klug, Mercedes

    2004-01-01

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

  7. REDUCING AMBIGUITY IN THE FUNCTIONAL ASSESSMENT OF PROBLEM BEHAVIOR

    PubMed Central

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

    2015-01-01

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

  8. 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

  9. Precise Point Positioning with Partial Ambiguity Fixing

    PubMed Central

    Li, Pan; Zhang, Xiaohong

    2015-01-01

    Reliable and rapid ambiguity resolution (AR) is the key to fast precise point positioning (PPP). We propose a modified partial ambiguity resolution (PAR) method, in which an elevation and standard deviation criterion are first used to remove the low-precision ambiguity estimates for AR. Subsequently the success rate and ratio-test are simultaneously used in an iterative process to increase the possibility of finding a subset of decorrelated ambiguities which can be fixed with high confidence. One can apply the proposed PAR method to try to achieve an ambiguity-fixed solution when full ambiguity resolution (FAR) fails. We validate this method using data from 450 stations during DOY 021 to 027, 2012. Results demonstrate the proposed PAR method can significantly shorten the time to first fix (TTFF) and increase the fixing rate. Compared with FAR, the average TTFF for PAR is reduced by 14.9% for static PPP and 15.1% for kinematic PPP. Besides, using the PAR method, the average fixing rate can be increased from 83.5% to 98.2% for static PPP, from 80.1% to 95.2% for kinematic PPP respectively. Kinematic PPP accuracy with PAR can also be significantly improved, compared to that with FAR, due to a higher fixing rate. PMID:26067196

  10. Precise Point Positioning with Partial Ambiguity Fixing.

    PubMed

    Li, Pan; Zhang, Xiaohong

    2015-01-01

    Reliable and rapid ambiguity resolution (AR) is the key to fast precise point positioning (PPP). We propose a modified partial ambiguity resolution (PAR) method, in which an elevation and standard deviation criterion are first used to remove the low-precision ambiguity estimates for AR. Subsequently the success rate and ratio-test are simultaneously used in an iterative process to increase the possibility of finding a subset of decorrelated ambiguities which can be fixed with high confidence. One can apply the proposed PAR method to try to achieve an ambiguity-fixed solution when full ambiguity resolution (FAR) fails. We validate this method using data from 450 stations during DOY 021 to 027, 2012. Results demonstrate the proposed PAR method can significantly shorten the time to first fix (TTFF) and increase the fixing rate. Compared with FAR, the average TTFF for PAR is reduced by 14.9% for static PPP and 15.1% for kinematic PPP. Besides, using the PAR method, the average fixing rate can be increased from 83.5% to 98.2% for static PPP, from 80.1% to 95.2% for kinematic PPP respectively. Kinematic PPP accuracy with PAR can also be significantly improved, compared to that with FAR, due to a higher fixing rate. PMID:26067196

  11. Quantum entropic ambiguities: Ethylene

    NASA Astrophysics Data System (ADS)

    Balachandran, A. P.; Queiroz, Amilcar; Vaidya, S.

    2013-07-01

    In a quantum system, there may be many density matrices associated with a state on an algebra of observables. For each density matrix, one can compute its entropy. These are, in general, different. Therefore, one reaches the remarkable possibility that there may be many entropies for a given state [R. Sorkin (private communication)]. This ambiguity in entropy can often be traced to a gauge symmetry emergent from the nontrivial topological character of the configuration space of the underlying system. It can also happen in finite-dimensional matrix models. In the present work, we discuss this entropy ambiguity and its consequences for an ethylene molecule. This is a very simple and well-known system, where these notions can be put to tests. Of particular interest in this discussion is the fact that the change of the density matrix with the corresponding entropy increase drives the system towards the maximally disordered state with maximum entropy, where Boltzman’s formula applies. Besides its intrinsic conceptual interest, the simplicity of this model can serve as an introduction to a similar discussion of systems such as colored monopoles and the breaking of color symmetry.

  12. Sexual function after surgical treatment for penile cancer: Which organ-sparing approach gives the best results?

    PubMed Central

    Sedigh, Omid; Falcone, Marco; Ceruti, Carlo; Timpano, Massimiliano; Preto, Mirko; Oderda, Marco; Kuehhas, Franklin; Sibona, Mattia; Gillo, Arianna; Gontero, Paolo; Rolle, Luigi; Frea, Bruno

    2015-01-01

    Introduction: We compared the postoperative sexual function of patients who underwent wide local excision (WLE) and glansectomy with urethral glanduloplasty for penile cancer. Methods: We retrospectively reviewed clinical data of 41 patients affected by superficial, localized penile cancer (≤cT2a) between 2006 and 2013. Patients with severe erectile dysfunction and not interested in resuming an active sexual life were selected for penile partial amputation. Patients with preoperative satisfying erectile function and concerned about the preservation of their sexual potency were scheduled for WLE (Group A) or glansectomy with urethral glanduloplasty (Group B). Sexual function was assessed with the International Index of Erectile Function (IIEF) questionnaire and the Sex Encounter Profile (SEP). At 1 year, patients were asked to complete the questionnaires again and were questioned about their genital sensibility and ejaculatory reflex persistence. Postoperative complications were reported according to the Clavien-Dindo classification. Statistical analysis was performed by two-tailed test: Student t-test and chi-square. Results: Among the 41 patients enrolled, 12 underwent WLE (29.2%), 23 glansectomy with urethral glanduloplasty (56%) and 6 with penile partial amputation (14.6%). A decrease in postoperative IIEF was recorded in both groups, but was statistically significant only in Group B (p = 0.003). As for the SEP, while no significant changes were recorded postoperatively in Group A, a marked reduction was reported for Group B, with a statistically significant decrease in the possibility of achieving penetrative intercourse (p = 0.006) and in the perceived satisfaction during sexual activity (p = 0.004). Conclusions: WLE lead to better sexual outcomes and less postoperative complications as compared to glansectomy with urethral glanduloplasty. PMID:26279710

  13. 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.

  14. Neural responses to category ambiguous words.

    PubMed

    Conwell, Erin

    2015-03-01

    Category ambiguous words (like hug and swing) have the potential to complicate both learning and processing of language. However, uses of such words may be disambiguated by acoustic differences that depend on the category of use. This article uses an event-related potential (ERP) technique to ask whether adult native speakers of English show neural sensitivity to those differences. The results indicate that noun and verb tokens of ambiguous words produce differences in the amplitude of the ERP response over left anterior sites as early as 100ms following stimulus onset and persisting for over 400ms. Nonsense words extracted from noun and verb contexts do not show such differences. These findings suggest that the acoustic differences between noun and verb tokens of ambiguous words are perceived and processed by adults and may be part of the lexical representation of the word. PMID:25637057

  15. Neural responses to category ambiguous words

    PubMed Central

    Conwell, Erin

    2015-01-01

    Category ambiguous words (like hug and swing) have the potential to complicate both learning and processing of language. However, uses of such words may be disambiguated by acoustic differences that depend on the category of use. This article uses an event-related potential (ERP) technique to ask whether adult native speakers of English show neural sensitivity to those differences. The results indicate that noun and verb tokens of ambiguous words produce differences in the amplitude of the ERP response over left anterior sites as early as 100 ms following stimulus onset and persisting for over 400 ms. Nonsense words extracted from noun and verb contexts do not show such differences. These findings suggest that the acoustic differences between noun and verb tokens of ambiguous words are perceived and processed by adults and may be part of the lexical representation of the word. PMID:25637057

  16. The Ambiguity of the English Present Perfect.

    ERIC Educational Resources Information Center

    Michaelis, Laura A.

    1994-01-01

    Examines grammatical and discourse-pragmatic reflexes of the existential and resultative readings of the English present perfect and presents negative and positive arguments regarding its ambiguity. It is suggested that the resultative verb represents a formal idiom and that mastery of aspectual grammar entails knowledge of form-meaning pairings.…

  17. 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.

  18. Rats are sensitive to ambiguity.

    PubMed

    Fast, Cynthia D; Blaisdell, Aaron P

    2011-12-01

    In the present study, we investigated response decisions made under conditions of incomplete information in rats. In Experiment 1, rats were trained on either a positive patterning (PP; A-, B-, AB+) or a negative patterning (NP; A+, B+, AB-) instrumental lever-press discrimination. Subjects that had learned an NP discrimination responded less to Cue A when Cue B was covered at test. The cover did not, however, affect test responses to Cue A in the PP condition. In Experiment 2, rats received concurrent training on both PP and NP discriminations. After concurrent training, responses to Cue A were different with B covered versus uncovered for both NP and PP discriminations. We discuss possible accounts for why exposure to a nonlinearly soluble discrimination (NP) may have affected sensitivity to cue ambiguity produced by the cover. These results have interesting implications for representational processes engaged in problem solving. PMID:21968926

  19. Situs ambiguous in a schoolchild.

    PubMed

    Tortajada, Miguel; Moreno, Miriam; Gracia, Miguel; Sanchis, Amparo

    2009-01-01

    We report the case of a 9-year-old child with asthma, atopic dermatitis and allergic rhinoconjunctivitis due to house dust mites, in whom a routine chest x-ray identified by chance abnormal organ position, such as the stomach located on the right side. Abdominal ultrasonography indicated a centralised liver, with polysplenia on the right side and an inferior cava vein located to the left of the aorta with no interruption. Ultrasonography did not show heart defects. Magnetic resonance imaging (MRI) of the abdomen was performed that showed a short pancreas, with no neck, body and tail in it, and a left inferior vena cava with normal outlet of the renal veins, and absence of the intrahepatic part of the inferior vena cava, that was replaced by the left hemiazygos vein. Spinal cord MRI revealed dorsal syringomelia. In view of the results obtained, the diagnosis of situs ambiguous was established. PMID:22121394

  20. P300 and Decision Making under Risk and Ambiguity

    PubMed Central

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

    2015-01-01

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

  1. A Statistical Approach for Ambiguous Sequence Mappings

    Technology Transfer Automated Retrieval System (TEKTRAN)

    When attempting to map RNA sequences to a reference genome, high percentages of short sequence reads are often assigned to multiple genomic locations. One approach to handling these “ambiguous mappings” has been to discard them. This results in a loss of data, which can sometimes be as much as 45% o...

  2. 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…

  3. Alcohol reduces aversion to ambiguity

    PubMed Central

    Tyszka, Tadeusz; Macko, Anna; Stańczak, 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

  4. The Ellipticity Distribution of Ambiguously Blended Objects

    NASA Astrophysics Data System (ADS)

    Dawson, William A.; Schneider, Michael D.; Tyson, J. Anthony; Jee, M. James

    2016-01-01

    Using overlapping fields with space-based Hubble Space Telescope and ground-based Subaru Telescope imaging we identify a population of blended galaxies that are blended to such a large degree that they are detected as single objects in the ground-based monochromatic imaging, which we label “ambiguous blends.” For deep imaging data, such as the depth targeted with the Large Synoptic Survey Telescope (LSST), the ambiguous blend population is both large (∼14%) and has a distribution of ellipticities that is different from that of unblended objects in a way that will likely be important for weak lensing measurements. Most notably, for a limiting magnitude of i ∼ 27 we find that ambiguous blending results in a ∼14% increase in shear noise (or an ∼12% decrease in the effective projected number density of lensed galaxies; neff) due to (1) larger intrinsic ellipticity dispersion, and (2) a scaling with the galaxy number density Ngal that is shallower than 1/\\sqrt{{N}{gal}}. For the LSST Gold Sample (i < 25.3) there is a ∼7% increase in shear noise (or ∼7% decrease in neff). More importantly than these increases in the shear noise, we find that the ellipticity distribution of ambiguous blends has an rms that is 13% larger than that of non-blended galaxies. Given the need of future weak lensing surveys to constrain the ellipticity distribution of galaxies to better than a percent in order to mitigate cosmic shear multiplicative biases, if it is unaccounted for, the different ellipticity distribution of ambiguous blends could be a dominant systematic.

  5. Ambiguous absence, ambiguous presence: a qualitative study of military reserve families in wartime.

    PubMed

    Faber, Anthony J; Willerton, Elaine; Clymer, Shelley R; MacDermid, Shelley M; Weiss, Howard M

    2008-04-01

    The "Global War on Terrorism" has resulted in reservists being deployed at an ever-increasing rate. However, because reservists and their families are unaccustomed to deployments, many families may experience boundary ambiguity, a state in which family members are uncertain in their perception about who is in or out of the family and who is performing which roles and tasks within the family. This qualitative description study examined boundary ambiguity in military reserve families over time. A sample of 34 reservists, spouses, and parents was interviewed 7 times within the 1st year of the reservists' return from Iraq. During deployment, all family members experienced boundary ambiguity. Gathering information and attending a family support group provided some relief for families. After the reservists returned, couples as well as those who had experienced additional life events or losses experienced the highest levels of boundary ambiguity. However, this boundary ambiguity dissipated over time, as families tended to restabilize once the reservists had returned to work and a routine had been established. PMID:18410209

  6. 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 “fronto—parietal—striatal” network including regions within the dorsolateral prefrontal cortex, intraparietal sulcus, and dorsal striatum. Activation was greatest across these regions and additional anterior and superior prefrontal regions for the quadratic function which most heavily weighs trials with partial ambiguity. These results suggest that the neural regions involved in decision processes do not merely track the absolute degree ambiguity or type of uncertainty (risk vs. ambiguity). Instead, recruitment of prefrontal regions may result from greater degree of difficulty in conditions of partial ambiguity: when information regarding reward probabilities important for decision making is hidden or not easily obtained the subject must engage in a search for tractable information. Additionally, this study identified regions of activity related to the valuation of potential gains associated with stimuli or options (including the orbitofrontal and medial prefrontal cortices and dorsal striatum) and related to winning (including orbitofrontal cortex and ventral striatum). PMID:24367286

  7. 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

  8. Giving behavior of millionaires

    PubMed Central

    Smeets, Paul; Bauer, Rob; Gneezy, Uri

    2015-01-01

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

  9. Giving behavior of millionaires.

    PubMed

    Smeets, Paul; Bauer, Rob; Gneezy, Uri

    2015-08-25

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

  10. 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…

  11. 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…

  12. 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

  13. De morseir syndrome presenting as ambiguous genitalia

    PubMed Central

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

    2012-01-01

    Background: A 10-year-old boy presented with genital ambiguity, poor linear growth, and delayed milestones. The aim and to highlight that although rare but congenital, hypogonadotropic hypogonadism may rarely present as ambiguity. Materials and Methods: The patient was found to have bilateral cryptorchidism with proximal penile hypospadias, microphallus with a proportionate dwarfism with mildly delayed bone age, and karyotype 46XY. Euthyroid with normal steroid axis, growth hormone insufficient as suggested by auxology, low IGF1, and poor response to clonidine stimulation. MRI brain shows hypoplastic corpus callosum, hypoplastic anterior pituitary, and ectopic posterior pituitary bright spot. Results: The patient underwent laparoscopic removal of right intrabdominal testis and orchidoplexy was performed on the left one. Testicular biopsy revealed no malignancy and growth hormone replacement was initiated. The patient awaits definitive repair of hypospadias. Conclusion: As a provisional diagnosis of combined growth hormone and gonadotropin deficiency, most probable diagnosis is septo-optic dysplasia or de moseir syndrome leading to genital ambiguity. PMID:23565482

  14. 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.

  15. How do speakers avoid ambiguous linguistic expressions?

    PubMed

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

    2005-07-01

    Three experiments assessed how speakers avoid linguistically and nonlinguistically ambiguous expressions. Speakers described target objects (a flying mammal, bat) in contexts including foil objects that caused linguistic (a baseball bat) and nonlinguistic (a larger flying mammal) ambiguity. Speakers sometimes avoided linguistic-ambiguity, and they did so equally regardless of whether they also were about to describe foils. This suggests that comprehension processes can sometimes detect linguistic-ambiguity before producing it. However, once produced, speakers consistently avoided using the same linguistically ambiguous expression again for a different meaning. This suggests that production processes can successfully detect linguistic-ambiguity after-the-fact. Speakers almost always avoided nonlinguistic-ambiguity. Thus, production processes are especially sensitive to nonlinguistic- but not linguistic-ambiguity, with the latter avoided consistently only once it is already articulated. PMID:15996561

  16. Reliability of partial ambiguity fixing with multiple GNSS constellations

    NASA Astrophysics Data System (ADS)

    Wang, Jun; Feng, Yanming

    2013-01-01

    Reliable ambiguity resolution (AR) is essential to real-time kinematic (RTK) positioning and its applications, since incorrect ambiguity fixing can lead to largely biased positioning solutions. A partial ambiguity fixing technique is developed to improve the reliability of AR, involving partial ambiguity decorrelation (PAD) and partial ambiguity resolution (PAR). Decorrelation transformation could substantially amplify the biases in the phase measurements. The purpose of PAD is to find the optimum trade-off between decorrelation and worst-case bias amplification. The concept of PAR refers to the case where only a subset of the ambiguities can be fixed correctly to their integers in the integer least squares (ILS) estimation system at high success rates. As a result, RTK solutions can be derived from these integer-fixed phase measurements. This is meaningful provided that the number of reliably resolved phase measurements is sufficiently large for least-square estimation of RTK solutions as well. Considering the GPS constellation alone, partially fixed measurements are often insufficient for positioning. The AR reliability is usually characterised by the AR success rate. In this contribution, an AR validation decision matrix is firstly introduced to understand the impact of success rate. Moreover the AR risk probability is included into a more complete evaluation of the AR reliability. We use 16 ambiguity variance-covariance matrices with different levels of success rate to analyse the relation between success rate and AR risk probability. Next, the paper examines during the PAD process, how a bias in one measurement is propagated and amplified onto many others, leading to more than one wrong integer and to affect the success probability. Furthermore, the paper proposes a partial ambiguity fixing procedure with a predefined success rate criterion and ratio test in the ambiguity validation process. In this paper, the Galileo constellation data is tested with simulated observations. Numerical results from our experiment clearly demonstrate that only when the computed success rate is very high, the AR validation can provide decisions about the correctness of AR which are close to real world, with both low AR risk and false alarm probabilities. The results also indicate that the PAR procedure can automatically chose adequate number of ambiguities to fix at given high-success rate from the multiple constellations instead of fixing all the ambiguities. This is a benefit that multiple GNSS constellations can offer.

  17. [A neonate with ambiguous genitalia].

    PubMed

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

    2015-01-01

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

  18. Where Does Sociopragmatic Ambiguity Come From?

    ERIC Educational Resources Information Center

    Burt, Susan Meredith

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

  19. 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…

  20. Implications of Ambiguity for Scientometric Measurement.

    ERIC Educational Resources Information Center

    Bookstein, A.

    2001-01-01

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

  1. Ambiguity, Cognition, Learning, Teaching, and Design

    ERIC Educational Resources Information Center

    Visser, Jan; Visser, Yusra Laila

    2004-01-01

    Many people in the instructional design community may wonder why AECT should devote a special session during its most recent International Convention in Anaheim, CA, to the issue of ambiguity. Isn't the whole idea behind well designed instruction that it should be ambiguity-free? If a debate on the issue of ambiguity is necessary at all, shouldn't…

  2. 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…

  3. Generative Learning: Adults Learning within Ambiguity

    ERIC Educational Resources Information Center

    Nicolaides, Aliki

    2015-01-01

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

  4. Generative Learning: Adults Learning within Ambiguity

    ERIC Educational Resources Information Center

    Nicolaides, Aliki

    2015-01-01

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

  5. 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

  6. Which smokers are helped to give up smoking using transdermal nicotine patches? Results from a randomized, double-blind, placebo-controlled trial.

    PubMed Central

    Yudkin, P L; Jones, L; Lancaster, T; Fowler, G H

    1996-01-01

    BACKGROUND: Nicotine replacement therapy is effective in helping people to give up smoking. The three forms now available--transdermal patches, chewing gum and nasal spray--deliver nicotine at different rates and to different levels. Therefore, it might be expected that smokers with different characteristics, and at different levels of nicotine dependence, will be helped more by one or other method. AIM: The aim of the study was to examine whether the effectiveness of transdermal patches is related to nicotine dependence or to other smoker characteristics and to investigate factors predicting smoking cessation using patches. METHOD: Data from a randomized, double-blind, placebo-controlled trial of nicotine transdermal patches were analysed retrospectively. The trial, conducted in 1990-1992, involved 1686 patients recruited from 19 general practices in Oxfordshire. The main outcome measure was continuous smoking cessation from 8 to 52 weeks after the start of patch use, biochemically validated at 12, 24 and 52 weeks. The effectiveness of the patches was measured by the relative odds of sustained cessation using nicotine patches compared with placebo patches. RESULTS: Nicotine transdermal patches were more effective in smokers with moderate nicotine dependence [odds ratio (OR) 1.94; 95% confidence interval (CI) 1.24-3.04] than in mildly or highly dependent smokers (OR 0.98; 95% CI 0.58-1.65) (difference in ORs P < 0.05) and more effective in those aged 24-49 years (OR 1.89; 95% CI 1.24-2.87) than in older smokers aged 50-65 years (OR 0.88; 95% CI 0.49-1.59) (difference in ORs P < 0.05). Abstinence from smoking in the first week of the trial was the strongest predictor of sustained cessation and was more common among smokers using nicotine patches than those using placebo patches (33% of 842 compared with 22% of 844; P < 0.001). Of first-week abstainers, 25 and 28% of 277 and 182 in the nicotine and placebo groups, respectively, achieved sustained cessation compared with 4% of 565 and 2% of 662 first-week smokers. CONCLUSION: Nicotine transdermal patches were most effective for smokers with moderate nicotine dependence and for younger smokers. Early abstinence from smoking was the strongest predictor of sustained cessation. A week's trial of the patch proceeding to longer term use if abstinence is achieved may be an effective policy. PMID:8731618

  7. Flexible taxonomic assignment of ambiguous sequencing reads

    PubMed Central

    2011-01-01

    Background To characterize the diversity of bacterial populations in metagenomic studies, sequencing reads need to be accurately assigned to taxonomic units in a given reference taxonomy. Reads that cannot be reliably assigned to a unique leaf in the taxonomy (ambiguous reads) are typically assigned to the lowest common ancestor of the set of species that match it. This introduces a potentially severe error in the estimation of bacteria present in the sample due to false positives, since all species in the subtree rooted at the ancestor are implicitly assigned to the read even though many of them may not match it. Results We present a method that maps each read to a node in the taxonomy that minimizes a penalty score while balancing the relevance of precision and recall in the assignment through a parameter q. This mapping can be obtained in time linear in the number of matching sequences, because LCA queries to the reference taxonomy take constant time. When applied to six different metagenomic datasets, our algorithm produces different taxonomic distributions depending on whether coverage or precision is maximized. Including information on the quality of the reads reduces the number of unassigned reads but increases the number of ambiguous reads, stressing the relevance of our method. Finally, two measures of performance are described and results with a set of artificially generated datasets are discussed. Conclusions The assignment strategy of sequencing reads introduced in this paper is a versatile and a quick method to study bacterial communities. The bacterial composition of the analyzed samples can vary significantly depending on how ambiguous reads are assigned depending on the value of the q parameter. Validation of our results in an artificial dataset confirm that a combination of values of q produces the most accurate results. PMID:21211059

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

    PubMed Central

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

    2015-01-01

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

  9. 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

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

    PubMed

    Philipp-Metzen, H E

    2011-12-01

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

  11. 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 .

  12. Evolution of phage with chemically ambiguous proteomes

    PubMed Central

    Bacher, Jamie M; Bull, James J; Ellington, Andrew D

    2003-01-01

    Background The widespread introduction of amino acid substitutions into organismal proteomes has occurred during natural evolution, but has been difficult to achieve by directed evolution. The adaptation of the translation apparatus represents one barrier, but the multiple mutations that may be required throughout a proteome in order to accommodate an alternative amino acid or analogue is an even more daunting problem. The evolution of a small bacteriophage proteome to accommodate an unnatural amino acid analogue can provide insights into the number and type of substitutions that individual proteins will require to retain functionality. Results The bacteriophage Q? initially grows poorly in the presence of the amino acid analogue 6-fluorotryptophan. After 25 serial passages, the fitness of the phage on the analogue was substantially increased; there was no loss of fitness when the evolved phage were passaged in the presence of tryptophan. Seven mutations were fixed throughout the phage in two independent lines of descent. None of the mutations changed a tryptophan residue. Conclusions A relatively small number of mutations allowed an unnatural amino acid to be functionally incorporated into a highly interdependent set of proteins. These results support the 'ambiguous intermediate' hypothesis for the emergence of divergent genetic codes, in which the adoption of a new genetic code is preceded by the evolution of proteins that can simultaneously accommodate more than one amino acid at a given codon. It may now be possible to direct the evolution of organisms with novel genetic codes using methods that promote ambiguous intermediates. PMID:14667253

  13. Ambiguity function analysis of wideband radars

    NASA Astrophysics Data System (ADS)

    Lush, David C.; Hudson, Dean A.

    A brief background and justification of the wideband ambiguity function is provided, and an expression is derived for the ambiguity function for a fairly broad class of coherent wideband radars. The class of radars described includes those utilizing pulse-to-pulse frequency agility, phase-shift coding, and discrete Fourier transform processing. The ambiguity function is reduced to one which is more suitable for computer circulation, and the implementation of a procedure for computing the ambiguity function at any point in the ambiguity plane is described. Two wideband ambiguity function examples computed using this procedure are presented, illustrating distortions due to wideband effects. The method can be used for analysis of various radar approaches, including phase-shift and frequency coding, when surveillance requirements lead to waveforms with large time-bandwidth products.

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

    PubMed Central

    Shou, Yiyun; Smithson, Michael

    2015-01-01

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

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

    SciTech Connect

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

    2014-05-02

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

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

    PubMed

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

    2016-01-01

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

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

    PubMed Central

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

    2016-01-01

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

  18. 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

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

    PubMed

    Urcuioli, Peter J; Michalek, Sarah

    2007-08-01

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

  20. 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.

  1. Word segmentation of overlapping ambiguous strings during Chinese reading

    PubMed Central

    Ma, Guojie; Li, Xingshan; Rayner, Keith

    2014-01-01

    In three experiments, we tested three possible mechanisms for segmenting overlapping ambiguous strings in Chinese reading. The first two characters and the last two characters in a 3-character ambiguous string could both constitute a word in the reported studies. The left-priority hypothesis assumes that the word on the left has an advantage in the competition and the other word cannot be processed until the word on the left is recognized. The independent processing hypothesis assumes that words in different positions are processed simultaneously and independently, and the word segmentation ambiguity cannot be settled without the help of sentence context. The competition hypothesis assumes that all of the words compete for a single winner. The results support a competition account that the characters in the perceptual span activate all of the words they can constitute, and any word can win the competition if its activation is high enough. PMID:24417292

  2. 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…

  3. 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

  4. 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…

  5. 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),…

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

    NASA Technical Reports Server (NTRS)

    Holmquist, R.; Jukes, T. H.

    1972-01-01

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

  7. 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.

  8. Giving Students Feedback.

    ERIC Educational Resources Information Center

    Lowman, Joseph

    1987-01-01

    Some of the special challenges associated with evaluation and grading in the large class are discussed. Suggestions for evaluation methods include seeking clarity, reducing the stress of test administration, giving feedback, guarding against errors in record keeping, and returning exams efficiently and with respect. (MLW)

  9. 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…

  10. Ambiguities in 'killing' and 'letting die'.

    PubMed

    Atkinson, G M

    1983-05-01

    In a recent article Carla Kary (1980) attempts to show that there can be a significant moral difference between instances of killing and letting die. I shall maintain in Section I that Kary's argument is somewhat weakened by her failure to note an important ambiguity in the notion of killing a person. I shall also argue in Section II that a similar ambiguity affects the notion of letting someone die, and that failure to note this latter ambiguity also weakens the position developed by Robert Coburn (1980) with regard to defective newborns. PMID:6886572

  11. Can People Creative in Imagery Interpret Ambiguous Figures Faster than People Less Creative in Imagery?

    ERIC Educational Resources Information Center

    Riquelme, Hernan

    2002-01-01

    A study involving 47 Chinese managers investigated whether those who were creative in imagery were better at interpreting ambiguous figures. Results found managers who were creative in imagery were more capable in interpreting ambiguous figures and were quicker in their discoveries than managers less creative in imagery. (Contains references.)

  12. 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

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

    PubMed Central

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

    2003-01-01

    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

  14. Clock ambiguity and the emergence of physical laws

    SciTech Connect

    Albrecht, Andreas; Iglesias, Alberto

    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.

  15. Resolving the ambiguity: Making sense of intrinsic disorder when PDB structures disagree.

    PubMed

    DeForte, Shelly; Uversky, Vladimir N

    2016-03-01

    Missing regions in X-ray crystal structures in the Protein Data Bank (PDB) have played a foundational role in the study of intrinsically disordered protein regions (IDPRs), especially in the development of in silico predictors of intrinsic disorder. However, a missing region is only a weak indication of intrinsic disorder, and this uncertainty is compounded by the presence of ambiguous regions, where more than one structure of the same protein sequence "disagrees" in terms of the presence or absence of missing residues. The question is this: are these ambiguous regions intrinsically disordered, or are they the result of static disorder that arises from experimental conditions, ensembles of structures, or domain wobbling? A novel way of looking at ambiguous regions in terms of the pattern between multiple PDB structures has been demonstrated. It was found that the propensity for intrinsic disorder increases as the level of ambiguity decreases. However, it is also shown that ambiguity is more likely to occur as the protein region is placed within different environmental conditions, and even the most ambiguous regions as a set display compositional bias that suggests flexibility. The results suggested that ambiguity is a natural result for many IDPRs crystallized under different conditions and that static disorder and wobbling domains are relatively rare. Instead, it is more likely that ambiguity arises because many of these regions were conditionally or partially disordered. PMID:26683124

  16. Role Conflict and Ambiguity in Complex Organizations

    ERIC Educational Resources Information Center

    Rizzo, John R.; And Others

    1970-01-01

    Study describes the development and testing of questionnaire measures of role conflict and ambiguity. Analyses of responses of managers show these two constructs to be factorially identifiable and independent. (Author/KJ)

  17. Ambiguities in spaceborne synthetic aperture radar systems

    NASA Technical Reports Server (NTRS)

    Li, F. K.; Johnson, W. T. K.

    1983-01-01

    An examination of aspects of spaceborne SAR time delay and Doppler ambiguities has led to the formulation of an accurate method for the evaluation of the ratio of ambiguity intensities to that of the signal, which has been applied to the nominal SAR system on Seasat. After discussing the variation of this ratio as a function of orbital latitude and attitude control error, it is shown that the detailed range migration-azimuth phase history of an ambiguity is different from that of a signal, so that the images of ambiguities are dispersed. Seasat SAR dispersed images are presented, and their dispersions are eliminated through an adjustment of the processing parameters. A method is also presented which uses a set of multiple pulse repetition sequences to determine the Doppler centroid frequency absolute values for SARs with high carrier frequencies and poor attitude measurements.

  18. Give/Take

    Energy Science and Technology Software Center (ESTSC)

    2007-09-12

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

  19. 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

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

    PubMed

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

    2015-01-01

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

  1. GNSS integer ambiguity validation based on posterior probability

    NASA Astrophysics Data System (ADS)

    Wu, Zemin; Bian, Shaofeng

    2015-10-01

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

  2. 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.

  3. Probability judgments under ambiguity and conflict

    PubMed Central

    Smithson, Michael

    2015-01-01

    Whether conflict and ambiguity are distinct kinds of uncertainty remains an open question, as does their joint impact on judgments of overall uncertainty. This paper reviews recent advances in our understanding of human judgment and decision making when both ambiguity and conflict are present, and presents two types of testable models of judgments under conflict and ambiguity. The first type concerns estimate-pooling to arrive at “best” probability estimates. The second type is models of subjective assessments of conflict and ambiguity. These models are developed for dealing with both described and experienced information. A framework for testing these models in the described-information setting is presented, including a reanalysis of a multi-nation data-set to test best-estimate models, and a study of participants' assessments of conflict, ambiguity, and overall uncertainty reported by Smithson (2013). A framework for research in the experienced-information setting is then developed, that differs substantially from extant paradigms in the literature. This framework yields new models of “best” estimates and perceived conflict. The paper concludes with specific suggestions for future research on judgment and decision making under conflict and ambiguity. PMID:26042081

  4. Fearing to give life.

    PubMed

    Wallace, B

    1992-01-01

    Fear of HIV infection and AIDS has contributed to the development of a global shortage, especially in Africa, of available blood for transfusions. Potential donors may be suspicious of the blood-giving process, that volunteer blood is sold, that those in need do not benefit, and of whether confidentiality will be maintained over their HIV status. Uncourteous and disaffected clinic workers have also contributed to donor erosion. Blood supplies must, however, be maintained in quantities adequate to meet patient needs around the world. With an over 90% probability of contracting HIV from 1 transfusion of infected blood, the importance of screening out potentially unsafe donors, recruiting from low risk populations, and discouraging high risk persons from donating should not be underestimated. To increase the available pool of willing and safe donors, sensitive and creative recruitment campaigns are suggested. Incentives which acknowledge donors' public spirit of giving, encouraging blood donations from prominent officials, and fostering regular education sessions from frequent donors are examples of potential strategies. Further, alternatives to transfusions should be encouraged where appropriate. Recruiters now target school-age youths in Zimbabwe and rural villagers in Rwanda as highly probably safe sources of blood. PMID:12284778

  5. 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.

  6. 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.

  7. Ps-LAMBDA: Ambiguity success rate evaluation software for interferometric applications

    NASA Astrophysics Data System (ADS)

    Verhagen, Sandra; Li, Bofeng; Teunissen, Peter J. G.

    2013-04-01

    Integer ambiguity resolution is the process of estimating the unknown ambiguities of carrier-phase observables as integers. It applies to a wide range of interferometric applications of which Global Navigation Satellite System (GNSS) precise positioning is a prominent example. GNSS precise positioning can be accomplished anytime and anywhere on Earth, provided that the integer ambiguities of the very precise carrier-phase observables are successfully resolved. As wrongly resolved ambiguities may result in unacceptably large position errors, it is crucial that one is able to evaluate the probability of correct integer ambiguity estimation. This ambiguity success rate depends on the underlying mathematical model as well as on the integer estimation method used. In this contribution, we present the Matlab toolbox Ps-LAMBDA for the evaluation of the ambiguity success rates. It allows users to evaluate all available success rate bounds and approximations for different integer estimators. An assessment of the sharpness of the bounds and approximations is given as well. Furthermore, it is shown how the toolbox can be used to assess the integer ambiguity resolution performance for design and research purposes, so as to study for instance the impact of using different GNSS systems and/or different measurement scenarios.

  8. 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

  9. 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 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

  10. 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

  11. Improved PPP ambiguity resolution by COES FCB estimation

    NASA Astrophysics Data System (ADS)

    Li, Yihe; Gao, Yang; Shi, Junbo

    2016-01-01

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

  12. Improved PPP ambiguity resolution by COES FCB estimation

    NASA Astrophysics Data System (ADS)

    Li, Yihe; Gao, Yang; Shi, Junbo

    2016-05-01

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

  13. Give Me... Your Huddled Masses...

    ERIC Educational Resources Information Center

    Wilkinson, Ray

    2000-01-01

    Explores the ambiguity in the attitudes of the U. S. and Canadian governments toward what are perceived as "real" refugees and more dubious asylum seekers. Outlines policies toward asylum seekers, points out inconsistencies, and notes some recently proposed changes in immigration law. (SLD)

  14. Ambiguity Can Be Pragmatic, and a Good Thing, Too.

    ERIC Educational Resources Information Center

    Chen, Rong

    Both the speaker and hearer of a conversation can make use of ambiguity to achieve their special purpose in a given situation. The strategies stemming from pragmatic ambiguity offer distinct advantages to speakers and hearers. When dealing with ambiguity, linguists have concentrated on the source of ambiguity and how to analyze it. References to…

  15. Clarity and ambiguity in psychoanalytic practice.

    PubMed

    Szajnberg, Nathan

    2011-03-01

    The author explores the presence and the essential tension between clarity and ambiguity as processes within our minds that become prominent in psychoanalysis. We learn from aesthetics and literary criticism that ambiguity can shade from taut disorganization to tolerating life's richness; clarity can range from a concrete fixity to a lucid grasp of one's state of mind. This article responds to Wallerstein's (1991) challenge to find common ground in psychoanalytic practice: We attempt this by avoiding metapsychological jargon and relying on more experience-near terms, such as clarity and ambiguity. The article also refers to Sandler's (1983) concept of implicit theory-that psychoanalysts use "preconscious, overlapping but not fully integrated models" (Sandler, 1988, p. 388)-in this case explicating how clarity and ambiguity are frequent but implicit phenomena in clinical work. Identifying these and the essential tension between them permits us to both improve training and identify our clinical efforts. The analyst's and analysand's tolerance of the tension between clarity and ambiguity facilitates increased structuralization and emotional robustness. PMID:21500957

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

    ERIC Educational Resources Information Center

    Pasley, B. Kay; Ihinger-Tallman, Marilyn

    1989-01-01

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

  17. Ambiguity-Avoidance: A Universal Constraint on Extraction from NP Sequences.

    ERIC Educational Resources Information Center

    Sweetser, Eve E.

    This research deals with how extraction rules are constrained in cases where their unconstrained application would give rise to semantic ambiguity. Of particular concern is the application of extraction rules to noun phrases (NP's) where word order is the only indication of the different syntactic functions of two adjacent NP's. Samples from…

  18. Phalloplasty in Complete Aphallia and Ambiguous Genitalia

    PubMed Central

    Bluebond-Langner, Rachel; Redett, Richard J.

    2011-01-01

    The most common indications for phalloplasty in children include aphallia, micropenis/severe penile inadequacy, ambiguous genitalia, phallic inadequacy associated with epispadias/bladder exstrophy and female to male gender reassignment in adolescents. There are many surgical options for phalloplasty; both local pedicled tissue as well as free tissue transfer. The advantages of local tissue include a more concealed donor site, less complex operation and potentially faster recovery. However, pedicled options are generally less sensate, making placement of a penile prosthesis more risky and many children with bladder exstrophy have been previously operated upon making the blood supply for local pedicled flaps less reliable. This Here the authors discuss free tissue transfer, including the radial forearm, the anterolateral thigh, the scapula and latissimus, and the fibula free flaps, as well as local rotational flaps from the abdomen, groin, and thigh. The goal of reconstruction should be an aesthetic and functional (ability to penetrate) phallus, which provides tactile and erogenous sensation, and the ability to urinate standing. Ideally, the operation should be completed in one to two operations with minimal donor site morbidity. There are advantages and disadvantages of each of flap and thus the choice of donor site should be a combination of the patient's preference and surgeon's ability to produce a consistent result. PMID:22851911

  19. Incidentally detected situs ambiguous in adults.

    PubMed

    Kim, Jae-Gyung; Youn, Ho-Joong; Kim, Gee-Hee; Park, Mi-Hee; Hur, Joon; Yu, Jin-Sok; Jung, Soo-Yeon; An, Soe-Hee

    2011-12-01

    Situs ambiguous is rare congenital anomaly in adults. In 2 adult patients who admitted for different cardiac problems, situs ambiguous with polysplenia was detected. A 42-year-old male admitted for radio frequent catheter ablation of atrial fibrillation, and he had left-sided inferior vena cava (IVC), hepatic segment of IVC interruption with hemiazygos continuation, multiple spleens and intestinal malrotation. And in a 52-year-old female case who was hospitalized due to infective endocarditis after implanting pacemaker for sick sinus syndrome, multiple spleens, left-sided stomach, bilateral liver with midline gallbladder, and left-sided IVC were found. Those findings were consistent with situs ambiguous with polysplenia, but their features were distinctive. PMID:22259667

  20. Quantization ambiguities in isotropic quantum geometry

    NASA Astrophysics Data System (ADS)

    Bojowald, Martin

    2002-10-01

    Some typical quantization ambiguities of quantum geometry are studied within isotropic models. Since this allows explicit computations of operators and their spectra, one can investigate the effects of ambiguities in a quantitative manner. It is shown that these ambiguities do not affect the fate of the classical singularity, demonstrating that the absence of a singularity in loop quantum cosmology is a robust implication of the general quantization scheme. The calculations also allow conclusions about modified operators in the full theory. In particular, using holonomies in a non-fundamental representation of SU(2) to quantize connection components turns out to lead to significant corrections to classical behaviour at macroscopic volume for large values of the spin of the chosen representation.

  1. [The ambiguity of the bioethics' principles].

    PubMed

    Pardo Caballos, Antonio

    2010-01-01

    The principles of the bioethics, coined in United States at the end of the seventies and diffused in our social environment one decade later, enclose inside a semantic ambiguity that here it is analyzed in their master lines; this ambiguity oscillates between a relativistic meaning and another agreed with the classic concept of Nature; this ambiguity has been transmitted to who, being part of the field of the Hippocratic medical ethics, have adopted its terminology, and these are the immense majority of the medical class. This phenomenon is easily leading towards the abandonment of the medical ethics based on the natural law (the Hippocratic-Christian tradition), to make it finish in a more or less clear relativism. to avoid this problem, some solutions in the field of the medical ethical terminology are proposed. PMID:20405972

  2. 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…

  3. Representation of lexical form: evidence from studies of sublexical ambiguity.

    PubMed

    McLennan, Conor T; Luce, Paul A; Charles-Luce, Jan

    2005-12-01

    The authors examined the role of intermediate, sublexical representations in spoken word perception. In particular, they tested whether flaps, which are neutralized allophones of intervocalic /t/s and /d/s, map onto their underlying phonemic counterparts. In 2 shadowing tasks, the authors found that flaps primed their carefully articulated counterparts, and vice versa. Because none of the flapped stimuli were lexically ambiguous (e.g., between rater and raider), these results provide evidence that such priming is sublexically mediated. Therefore, the current study provides further insights into when underlying form-based representations are activated during spoken word processing. In particular, the authors argue that phonological ambiguity, inherent in their flapped stimuli, is one of the conditions leading to the activation of underlying representations. PMID:16366791

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

    PubMed

    Kuang, Shenbing; Zhang, Tao

    2014-01-01

    Senses of smells are often accompanied by simultaneous visual sensations. Previous studies have documented enhanced olfactory performance with concurrent presence of congruent color- or shape- related visual cues, and facilitated visual object perception when congruent smells are simultaneously present. These visual object-olfaction interactions suggest the existences of couplings between the olfactory pathway and the visual ventral processing stream. However, it is not known if olfaction can modulate visual motion perception, a function that is related to the visual dorsal stream. We tested this possibility by examining the influence of olfactory cues on the perceptions of ambiguous visual motion signals. We showed that, after introducing an association between motion directions and olfactory cues, olfaction could indeed bias ambiguous visual motion perceptions. Our result that olfaction modulates visual motion processing adds to the current knowledge of cross-modal interactions and implies a possible functional linkage between the olfactory system and the visual dorsal pathway. PMID:25052162

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

    PubMed Central

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

    2016-01-01

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

  6. A new approach to modernized GPS phase-only ambiguity resolution over long baselines

    NASA Astrophysics Data System (ADS)

    Chu, Feng-Yu; Yang, Ming; Wu, Joz

    2016-03-01

    With the advent of modernized GPS, triple-frequency phase measurements (L1, L2, and L5) are available for civil use. The successful ambiguity resolution of the integer ambiguities of the phase measurements will be the key to centimeter-level positioning. In order to achieve ambiguity resolution over long baselines, code measurements (pseudorange) are regularly incorporated with the phase measurements in the observation model. However, code multipath affects ambiguity resolution and thus completely eliminating the influence is an important issue. Therefore, the present study proposes an approach that uses only the phase measurements in the observation model. The proposed approach has three steps and focuses on resolving the integer ambiguities of the triple-frequency phase measurements. Simulation baseline data were processed by the proposed approach and the results show that the integer ambiguities of the phase measurements can be successfully resolved and that satellite geometry is an important factor for the phase-only ambiguity resolution performance. Real triple-frequency GPS data from currently available Block IIF satellites were also processed to demonstrate the feasibility of the proposed approach.

  7. Dispositional sources of sanction perceptions: Emotionality, cognitive style, intolerance of ambiguity, and self-efficacy.

    PubMed

    Pickett, Justin T; Bushway, Shawn D

    2015-12-01

    This study contributes to efforts to identify the sources of arrest risk perceptions and ambiguity (or lack of confidence) in such perceptions. Drawing on dual-process theories of reasoning, we argue that arrest risk perceptions often represent intuitive judgments that are influenced by cognitive heuristics and dispositional attributes. Multivariate regression models are estimated with data from 3 national surveys to test 6 hypotheses about the relationships between specific dispositional attributes and perceived arrest risk and ambiguity. We find evidence that dispositional positive affect and intolerance of ambiguity are both positively related to perceived arrest risk, and are also both negatively related to ambiguity. We also find evidence that cognitive reflection and general self-efficacy are, respectively, positively and negatively associated with ambiguity. Mixed evidence emerges about whether cognitive reflection is related to risk perceptions, and about whether either dispositional negative affect or thoughtfully reflective decision making correlate with ambiguity. Taken together, the results provide partial support for each of our hypotheses, and suggest that dispositional attributes are important sources of perceptions of arrest risk as well as of ambiguity in such perceptions. PMID:26375260

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

    PubMed

    Dickter, Cheryl L; Kittel, Julie A

    2012-01-01

    Previous research has demonstrated that an early attentional component of the event-related potential (ERP), the P2, is sensitive to the distinction between the processing of racial outgroup and ingroup faces but may not be sensitive to the distinction between racially ambiguous and ingroup faces. Recent behavioral work, however, has suggested that contextual information may affect the processing of racially ambiguous faces. Thus, the first goal of this study was to examine whether the early neural processing of racially ambiguous faces would be affected by primed stereotypes. White college student participants (n = 29) completed a task in which they racially categorized monoracial Black and White faces and racially ambiguous Black-White morphs. These faces were preceded by positive and negative Black and White stereotypical primes. Results indicated that P2 amplitude to the racially ambiguous faces was moderated by the valence of the primes such that negative primes led to greater neural processing of the racially ambiguous faces than positive primes. Furthermore, the extent to which P2 amplitude was affected by prime valence was moderated by individual differences in preference for structure and categorical thinking, as well as comfort with ambiguity. PMID:22642396

  9. 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

  10. 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.

  11. 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…

  12. 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…

  13. 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…

  14. Ambiguity in Tactile Apparent Motion Perception

    PubMed Central

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

    2016-01-01

    Background In von Schiller’s Stroboscopic Alternative Motion (SAM) stimulus two visually presented diagonal dot pairs, located on the corners of an imaginary rectangle, alternate with each other and induce either horizontal, vertical or, rarely, rotational motion percepts. SAM motion perception can be described by a psychometric function of the dot aspect ratio (“AR”, i.e. the relation between vertical and horizontal dot distances). Further, with equal horizontal and vertical dot distances (AR = 1) perception is biased towards vertical motion. In a series of five experiments, we presented tactile SAM versions and studied the role of AR and of different reference frames for the perception of tactile apparent motion. Methods We presented tactile SAM stimuli and varied the ARs, while participants reported the perceived motion directions. Pairs of vibration stimulators were attached to the participants’ forearms and stimulator distances were varied within and between forearms. We compared straight and rotated forearm conditions with each other in order to disentangle the roles of exogenous and endogenous reference frames. Results Increasing the tactile SAM’s AR biased perception towards vertical motion, but the effect was weak compared to the visual modality. We found no horizontal disambiguation, even for very small tactile ARs. A forearm rotation by 90° kept the vertical bias, even though it was now coupled with small ARs. A 45° rotation condition with crossed forearms, however, evoked a strong horizontal motion bias. Discussion Existing approaches to explain the visual SAM bias fail to explain the current tactile results. Particularly puzzling is the strong horizontal bias in the crossed-forearm conditions. In the case of tactile apparent motion, there seem to be no fixed priority rule for perceptual disambiguation. Rather the weighting of available evidence seems to depend on the degree of stimulus ambiguity, the current situation and on the perceptual strategy of the individual observer. PMID:27171276

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

    PubMed Central

    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

  16. Improving the estimation of fractional-cycle biases for ambiguity resolution in precise point positioning

    NASA Astrophysics Data System (ADS)

    Geng, Jianghui; Shi, Chuang; Ge, Maorong; Dodson, Alan H.; Lou, Yidong; Zhao, Qile; Liu, Jingnan

    2012-08-01

    Ambiguity resolution dedicated to a single global positioning system (GPS) station can improve the accuracy of precise point positioning. In this process, the estimation accuracy of the narrow-lane fractional-cycle biases (FCBs), which destroy the integer nature of undifferenced ambiguities, is crucial to the ambiguity-fixed positioning accuracy. In this study, we hence propose the improved narrow-lane FCBs derived from an ambiguity-fixed GPS network solution, rather than the original (i.e. previously proposed) FCBs derived from an ambiguity-float network solution. The improved FCBs outperform the original FCBs by ensuring that the resulting ambiguity-fixed daily positions coincide in nature with the state-of-the-art positions generated by the International GNSS Service (IGS). To verify this improvement, 1 year of GPS measurements from about 350 globally distributed stations were processed. We find that the original FCBs differ more from the improved FCBs when fewer stations are involved in the FCB estimation, especially when the number of stations is less than 20. Moreover, when comparing the ambiguity-fixed daily positions with the IGS weekly positions for 248 stations through a Helmert transformation, for the East component, we find that on 359 days of the year the daily RMS of the transformed residuals based on the improved FCBs is smaller by up to 0.8 mm than those based on the original FCBs, and the mean RMS over the year falls evidently from 2.6 to 2.2 mm. Meanwhile, when using the improved rather than the original FCBs, the RMS of the transformed residuals for the East component of 239 stations (i.e. 96.4% of all 248 stations) is clearly reduced by up to 1.6 mm, especially for stations located within a sparse GPS network. Therefore, we suggest that narrow-lane FCBs should be determined with ambiguity-fixed, rather than ambiguity-float, GPS network solutions.

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

    NASA Astrophysics Data System (ADS)

    Taibu, Rex; Rudge, David; Schuster, David

    2015-06-01

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

  18. Charitable giving expenditures and the faith factor.

    PubMed

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

    2011-01-01

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

  19. Zero-difference GPS ambiguity resolution at CNES-CLS IGS Analysis Center

    NASA Astrophysics Data System (ADS)

    Loyer, Sylvain; Perosanz, Flix; Mercier, Flavien; Capdeville, Hugues; Marty, Jean-Charles

    2012-11-01

    CNES (Centre National d'Etudes Spatiales) and CLS (Collecte Localisation Satellites) became an International GNSS Service (IGS) Analysis Center (AC) the 20th of May 2010. Since 2009, we are using the integer ambiguity fixing at the zero-difference level strategy in our software package (GINS/Dynamo) as an alternative to classical differential approaches. This method played a key role among all the improvements in the GPS processing we made during this period. This paper provides to the users the theoretical background, the strategies and the models used to compute the products (GPS orbits and clocks, weekly station coordinate estimates and Earth orientation parameters) that are submitted weekly to the IGS. The practical realization of the two-step, ambiguity-fixing scheme (wide-lane and narrow-lane) is described in detail. The ambiguity fixing improved our orbit overlaps from 6 to 3 cm WRMS in the tangential and normal directions. Since 2008, our products have been also regularly compared to the IGS final solutions by the IGS Analysis Center Coordinator. The joint effects of ambiguity fixing and dynamical model changes (satellite solar radiation pressure and albedo force) improved the consistency with IGS orbits from 35 to 18 mm 3D-WRMS. Our innovative strategy also gives additional powerful properties to the GPS satellite phase clock solutions. Single receiver (zero-difference) ambiguity resolution becomes possible. An overview of the applications is given.

  20. Relation of tolerance of ambiguity to global and specific paranormal experience.

    PubMed

    Houran, J; Williams, C

    1998-12-01

    We examined the relationship of tolerance of ambiguity to severe global factors and specific types of anomalous or paranormal experience. 107 undergraduate students completed MacDonald's 1970 AT-20 and the Anomalous Experiences Inventory of Kumar, Pekala, and Gallagher. Scores on the five subscales of the Anomalous Experiences Inventory correlated differently with tolerance of ambiguity. Global paranormal beliefs, abilities, experiences, and drug use were positively associated with tolerance of ambiguity, whereas a fear of paranormal experience showed a negative relation. The specific types of anomalous experiences that correlated with tolerance of ambiguity often involved internal or physiological experience, e.g., precognitive dreams, memories of reincarnation, visual apparitions, and vestibular alterations. We generally found no effects of age of sex. These results are consistent with the idea that some paranormal experiences are misattributions of internal experience to external ('paranormal') sources, a process analogous to mechanisms underpinning delusions and hallucinations. PMID:9923156

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

    PubMed

    Khaw, Lyndal; Hardesty, Jennifer L

    2015-06-01

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

  2. The processing of lexical ambiguity: homonymy and polysemy in the mental lexicon.

    PubMed

    Klepousniotou, Ekaterini

    2002-01-01

    Under the theoretical assumption that lexical ambiguity is not a homogeneous phenomenon, but rather that it is subdivided into two distinct types, namely homonymy and polysemy, the present study investigated whether these different types of lexical ambiguity are psychologically real. Four types of ambiguous words, homonymous words (e.g., "pen"), polysemous words with metaphorical extensions (e.g., "eye"), polysemous words with a count/mass metonymic extension (e.g., "turkey"), and polysemous words with a producer/product metonymic extension (e.g., "Dali"), were used in a cross-modal sentence-priming lexical decision task. Overall, the theoretical distinction between homonymy and polysemy was reflected in the results of the present study, which revealed differential processing depending on the type of ambiguity. PMID:12081393

  3. Interpreting ambiguous social cues in unpredictable contexts.

    PubMed

    Davis, F Caroline; Neta, Maital; Kim, M Justin; Moran, Joseph M; Whalen, Paul J

    2016-05-01

    Unpredictable environments can be anxiety-provoking and elicit exaggerated emotional responses to aversive stimuli. Even neutral stimuli, when presented in an unpredictable fashion, prime anxiety-like behavior and elicit heightened amygdala activity. The amygdala plays a key role in initiating responses to biologically relevant information, such as facial expressions of emotion. While some expressions clearly signal negative (anger) or positive (happy) events, other expressions (e.g. surprise) are more ambiguous in that they can predict either valence, depending on the context. Here, we sought to determine whether unpredictable presentations of ambiguous facial expressions would bias participants to interpret them more negatively. We used functional magnetic resonance imaging and facial electromyography (EMG) to characterize responses to predictable vs unpredictable presentations of surprised faces. We observed moderate but sustained increases in amygdala reactivity to predictable presentations of surprised faces, and relatively increased amygdala responses to unpredictable faces that then habituated, similar to previously observed responses to clearly negative (e.g. fearful) faces. We also observed decreased corrugator EMG responses to predictable surprised face presentations, similar to happy faces, and increased responses to unpredictable surprised face presentations, similar to angry faces. Taken together, these data suggest that unpredictability biases people to interpret ambiguous social cues negatively. PMID:26926605

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

    ERIC Educational Resources Information Center

    Marzban, Amin; Barati, Hossein; Moinzadeh, Ahmad

    2012-01-01

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

  5. 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.

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

    NASA Astrophysics Data System (ADS)

    Baroni, Leandro

    2015-10-01

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

  7. 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.

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

    PubMed

    Trautmann, Stefan T; Schmidt, Ulrich

    2012-01-01

    In the valuation of uncertain prospects, a difference is often observed between selling and buying perspectives. This paper distinguishes between risk (known probabilities) and ambiguity (unknown probabilities) in decisions under uncertainty and shows that the valuation disparity increases under ambiguity compared to risk. It is found that both the comparative versus noncomparative evaluation of risky and ambiguous prospects and the uniqueness of the valuation perspective (either seller or buyer) moderate this increase in the disparity under ambiguity. The finding is consistent with recent theoretical accounts of pricing under uncertainty. We discuss implications for market behaviour and for the ambiguity paradigm as a research tool. PMID:21961803

  10. Utilitarian relevance and face management in the interpretation of ambiguous question/request statements.

    PubMed

    Demeure, Virginie; Bonnefon, Jean-François; Raufaste, Eric

    2008-06-01

    Often, requests are made in an indirect manner and phrased in such a way that they can also be construed as questions. For example, the sentence "Is there any coffee left?" can be construed either as a question about coffee or as a request for coffee. This article offers a combined test of some key predictions of two approaches to the disambiguation of question/request statements: (1) the face management approach, which gives a prominent role to variables such as status and potential loss of face; and (2) the utilitarian relevance approach, which gives a prominent role to the goals pursued by the speaker at the time he or she issues the statement. Ambiguous question/request statements provide a natural test bed for the latter approach in particular. A board game paradigm is developed to allow for a clean, orthogonal manipulation of all variables. The results wholly support the utilitarian relevance approach and offer new perspectives on the face management approach. PMID:18604968

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

    SciTech Connect

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

    2007-10-01

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

  12. A United Methodist approach to end-of-life decisions: intentional ambiguity or ambiguous intentions.

    PubMed

    Thobaben, James R

    1997-12-01

    The position of the United Methodist Church on end-of-life decisions is best described as intentional ambiguity or ambiguous intentions or both. The paper analyzes the official position of the denomination and then considers the actions of a U.M.C. bishop who served as a foreman for a trial of Dr. Jack Kevorkian. In an effort to find some common ground within an increasingly divided denomination, the work concludes with a consideration of the work of John Wesley and his approach to human death. PMID:11655315

  13. Planned Giving for Catholic Schools.

    ERIC Educational Resources Information Center

    Bourbeau, Mary Ann

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

  14. GNSS triple-frequency geometry-free and ionosphere-free track-to-track ambiguities

    NASA Astrophysics Data System (ADS)

    Wang, Kan; Rothacher, Markus

    2015-06-01

    During the last few years, more and more GNSS satellites have become available sending signals on three or even more frequencies. Examples are the GPS Block IIF and the Galileo In-Orbit-Validation (IOV) satellites. Various investigations have been performed to make use of the increasing number of frequencies to find a compromise between eliminating different error sources and minimizing the noise level, including the investigations in the triple-frequency geometry-free (GF) and ionosphere-free (IF) linear combinations, which eliminate all the geometry-related errors and the first-order term of the ionospheric delays. In contrast to the double-difference GF and IF ambiguity resolution, the resolution of the so-called track-to-track GF and IF ambiguities between two tracks of a satellite observed by the same station only requires one receiver and one satellite. Most of the remaining errors like receiver and satellite delays (electronics, cables, etc.) are eliminated, if they are not changing rapidly in time, and the noise level is reduced theoretically by a factor of square root of two compared to double-differences. This paper presents first results concerning track-to-track ambiguity resolution using triple-frequency GF and IF linear combinations based on data from the Multi-GNSS Experiment (MGEX) from April 29 to May 9, 2012 and from December 23 to December 29, 2012. This includes triple-frequency phase and code observations with different combinations of receiver tracking modes. The results show that it is possible to resolve the combined track-to-track ambiguities of the best two triple-frequency GF and IF linear combinations for the Galileo frequency triplet E1, E5b and E5a with more than 99.6% of the fractional ambiguities for the best linear combination being located within ± 0.03 cycles and more than 98.8% of the fractional ambiguities for the second best linear combination within ± 0.2 cycles, while the fractional parts of the ambiguities for the GPS frequency triplet L1, L2 and L5 are more disturbed by errors as e.g. the uncalibrated Phase Center Offsets (PCOs) and Phase Center Variations (PCVs), that have not been considered. The best two GF and IF linear combinations between tracks are helpful to detect problems in data and receivers. Furthermore, resolving the track-to-track ambiguities is helpful to connect the single-receiver ambiguities on the normal equation level and to improve ambiguity resolution.

  15. 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

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

    PubMed

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

    2015-09-01

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

  17. Utilization of Prosodic Information in Syntactic Ambiguity Resolution

    PubMed Central

    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 subordinate verbs paired with implausible direct objects. Experiment 2 also contained early closure sentences with transitively and intransitive-biased subordinate verbs, but the subordinate verbs were always followed by plausible direct objects. In both experiments, there were two prosodic conditions. In the subject-biased prosodic condition, an intonational phrase boundary marked the clausal boundary following the subordinate verb. In the object-biased prosodic condition, the clause boundary was unmarked. The results indicate that lexical and prosodic cues interact at the subordinate verb and plausibility further affects processing at the ambiguous noun. Results are discussed with respect to models of the role of prosody in sentence comprehension. PMID:20033849

  18. Hemispheric asymmetries in semantic processing: evidence from false memories for ambiguous words.

    PubMed

    Faust, Miriam; Ben-Artzi, Elisheva; Harel, Itay

    2008-06-01

    Previous research suggests that the left hemisphere (LH) focuses on strongly related word meanings; the right hemisphere (RH) may contribute uniquely to the processing of lexical ambiguity by activating and maintaining a wide range of meanings, including subordinate meanings. The present study used the word-lists false memory paradigm [Roediger, H. L. III., & McDermott, K. B. (1995). Creating false memories: Remembering words not presented in lists. Journal of Experimental Psychology: Learning, Memory, and Cognition, 21, 803-814.] to examine whether these differences between the two cerebral hemispheres in semantic processing also affect memory representations for different meanings of ambiguous words. Specifically, we tested the differences between the LH and RH in recollecting unpresented, semantically related, ambiguous words following the presentation of lists of words all related to either the dominant or the subordinate meanings of these ambiguous words. Findings showed that for the unpresented ambiguous words, the LH made more false alarms than the RH for the dominant lists, whereas the opposite pattern emerged for subordinate lists. Moreover, d' analyses showed that, whereas the LH was more sensitive to subordinate than dominant meanings, the RH showed no differences in sensitivity for the two types of word-lists. Taken as a whole, these results support the RH coarse semantic coding theory [Beeman, M. (1998). Coarse semantic coding and discourse comprehension. In Beeman & M., Chiarello, C. (Eds.), Right hemisphere language comprehension: Perspectives from cognitive neuroscience (pp. 255-284). Mahwah, NJ: Erlbaum; Jung-Beeman, M. (2005). Bilateral brain processes for comprehending natural language. Trends in Cognitive Sciences, 9, 512-518.] indicating that during word recognition, the RH activates and maintains a broader and less differentiated range of related meanings than the LH, including both dominant and subordinate meanings of ambiguous words. Furthermore, the findings suggest that hemispheric differences in ambiguity resolution during language processing extend also to verbal memory. PMID:18178246

  19. 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.

  20. 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.

  1. Multi-timescale perceptual history resolves visual ambiguity.

    PubMed

    Brascamp, Jan W; Knapen, Tomas H J; Kanai, Ryota; Noest, André J; van Ee, Raymond; van den Berg, Albert V

    2008-01-01

    When visual input is inconclusive, does previous experience aid the visual system in attaining an accurate perceptual interpretation? Prolonged viewing of a visually ambiguous stimulus causes perception to alternate between conflicting interpretations. When viewed intermittently, however, ambiguous stimuli tend to evoke the same percept on many consecutive presentations. This perceptual stabilization has been suggested to reflect persistence of the most recent percept throughout the blank that separates two presentations. Here we show that the memory trace that causes stabilization reflects not just the latest percept, but perception during a much longer period. That is, the choice between competing percepts at stimulus reappearance is determined by an elaborate history of prior perception. Specifically, we demonstrate a seconds-long influence of the latest percept, as well as a more persistent influence based on the relative proportion of dominance during a preceding period of at least one minute. In case short-term perceptual history and long-term perceptual history are opposed (because perception has recently switched after prolonged stabilization), the long-term influence recovers after the effect of the latest percept has worn off, indicating independence between time scales. We accommodate these results by adding two positive adaptation terms, one with a short time constant and one with a long time constant, to a standard model of perceptual switching. PMID:18231584

  2. Is ambiguity tolerance malleable? Experimental evidence with potential implications for future research

    PubMed Central

    Endres, Megan L.; Camp, Richaurd; Milner, Morgan

    2015-01-01

    We conducted two research studies to address the malleability of tolerance of ambiguity (TA) by manipulating situational ambiguity. Students participated in a semester-end assessment of their management skills (n = 306). In Study 1, students in low and moderate ambiguity conditions had significantly higher post-experiment TA, more positive change in self-efficacy, and marginally higher faculty ratings. In Study 2, a control group (n = 103) did not participate in the assessment and was established for comparison to the first study results. The Study 2 students reported TA significantly lower than Study 1 students in the low and moderate ambiguity conditions. The control group TA was not significantly different from that of the Study 1 high ambiguity condition. This further suggested TA’s situational malleability, as those who had controlled access to structured information appeared to have increased their TA over that observed in the other two groups. These results suggest that TA may be malleable. We review the relevant literature, offer hypotheses, report our analyses and findings, and then propose future research, and potential prescriptive applications in such areas as management development, assessment, and decision-making. PMID:26042059

  3. Emolabeling Effectively Reduces the Influence of Ambiguous Labeling on Food Packages Among Grocery Store Shoppers

    PubMed Central

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

    2015-01-01

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

  4. 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.

  5. 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

  6. 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.

  7. Dealing with the Ambiguities of Science Inquiry

    NASA Astrophysics Data System (ADS)

    Tan, Yuen Sze Michelle; Caleon, Imelda Santos

    2016-03-01

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

  8. 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.

  9. The three Ts of giving.

    PubMed

    Yarborough, Craig S

    2009-04-01

    The profession of dentistry is recognized as one of the most trusted, honest, and ethical professions by many sources. But are we the most generous with the three Ts of philanthropic giving: time, talent, and treasure? We are fortunate to be able to do what we do and are rewarded accordingly. No matter what stage of dentistry our career is in, we should be able to give back to our profession, our communities, and society in one, if not all three, of the Ts of philanthropy. PMID:19830997

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

    PubMed

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

    2014-02-01

    Past research shows that adults often display poor memory for racially ambiguous and racial outgroup faces, with both face types remembered worse than own-race faces. In the present study, the authors examined whether children also show this pattern of results. They also examined whether emerging essentialist thinking about race predicts children's memory for faces. Seventy-four White children (ages 4-9 years) completed a face-memory task comprising White, Black, and racially ambiguous Black-White faces. Essentialist thinking about race was also assessed (i.e., thinking of race as immutable and biologically based). White children who used essentialist thinking showed the same bias as White adults: They remembered White faces significantly better than they remembered ambiguous and Black faces. However, children who did not use essentialist thinking remembered both White and racially ambiguous faces significantly better than they remembered Black faces. This finding suggests a specific shift in racial thinking wherein the boundaries between racial groups become more discrete, highlighting the importance of how race is conceptualized in judgments of racially ambiguous individuals. PMID:23815702

  11. Assessment of correct fixing rate for precise point positioning ambiguity resolution on a global scale

    NASA Astrophysics Data System (ADS)

    Zhang, Xiaohong; Li, Pan

    2013-06-01

    Ambiguity resolution (AR) for a single receiver has been a popular topic in Global Positioning System (GPS) recently. Ambiguity-resolution methods for precise point positioning (PPP) have been well documented in recent years, demonstrating that it can improve the accuracy of PPP. However, users are often concerned about the reliability of ambiguity-fixed PPP solution in practical applications. If ambiguities are fixed to wrong integers, large errors would be introduced into position estimates. In this paper, we aim to assess the correct fixing rate (CFR), i.e., number of ambiguities correctly fixing to the total number of ambiguities correctly and incorrectly fixing, for PPP user ambiguity resolution on a global scale. A practical procedure is presented to evaluate the CFR of PPP user ambiguity resolution. GPS data of the first 3 days in each month of 2010 from about 390 IGS stations are used for experiments. Firstly, we use GPS data collected from about 320 IGS stations to estimate global single-differenced (SD) wide-lane and narrow-lane satellite uncalibrated phase delays (UPDs). The quality of UPDs is evaluated. We found that wide-lane UPD estimates have a rather small standard deviation (Std) between 0.003 and 0.004 cycles while most of Std of narrow-lane estimates are from 0.01 to 0.02 cycles. Secondly, many experiments have been conducted to investigate the CFR of integer ambiguity resolution we can achieve under different conditions, including reference station density, observation session length and the ionospheric activity. The results show that the CFR of PPP can exceed 98.0 % with only 1 h of observations for most user stations. No obvious correlation between the CFR and the reference station density is found. Therefore, nearly homogeneous CFR can be achieved in PPP AR for global users. At user end, higher CFR could be achieved with longer observations. The average CFR for 30-min, 1-h, 2-h and 4-h observation is 92.3, 98.2, 99.5 and 99.7 %, respectively. In order to get acceptable CFR, 1 h is a recommended minimum observation time. Furthermore, the CFR of PPP can be affected by diurnal variation and geomagnetic latitude variation in the ionosphere. During one day at the hours when rapid ionospheric variations occur or in low geomagnetic latitude regions where equatorial electron density irregularities are produced relatively frequently, a significant degradation of the CFR is demonstrated.

  12. 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

  13. The New Planned Giving Officer.

    ERIC Educational Resources Information Center

    Jordan, Ronald R.; Quynn, Katelyn L.

    1994-01-01

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

  14. 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)

  15. 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…

  16. Range ambiguity suppression for multiple-input, multiple-output synthetic aperture radar system using azimuth phase coding technique

    NASA Astrophysics Data System (ADS)

    Guo, Lei; Wang, Robert; Deng, Yunkai; Wang, Wei; Luo, Xiulian

    2014-01-01

    For synthetic aperture radar (SAR), range ambiguity causes a great deterioration in imaging performance. To suppress range ambiguity, the azimuth phase coding (APC) technique stands out for its effectiveness with a low implementation complexity among the available approaches. With proper phase modulation and demodulation, the position of an ambiguous signal is shifted in Doppler spectrum and then part of the ambiguity can be filtered out by an azimuth filter. However, since the suppression performance heavily depends on the system oversampling rate, the APC technique cannot achieve the same suppression performance for a multichannel SAR system compared with a single-channel SAR system. A method to suppress the range ambiguity for multiple-input, multiple-output (MIMO) SAR system based on APC technique is presented. By taking advantage of more phase centers of the MIMO SAR, a proper azimuth beamformer weight vector can be computed to null out the ambiguity position in the azimuth frequency domain and reconstruct the useful signal; thus most of the ambiguity components can be significantly suppressed. Finally, the simulation results validate the effectiveness of the proposed method.

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

    PubMed

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

    2014-10-01

    We investigated individual difference predictors of ascribing ingroup characteristics to negative and positive ambiguous targets. Studies 1 and 2 investigated events involving negative targets whose status as racial (Tsarnaev brothers) or national (Woolwich attackers) ingroup members remained ambiguous. Immediately following the attacks, we presented White Americans and British individuals with the suspects' images. Those higher in social dominance orientation (SDO) and right-wing authoritarianism (RWA)-concerned with enforcing status boundaries and adherence to ingroup norms, respectively-perceived these low status and low conformity suspects as looking less White and less British, thus denying them ingroup characteristics. Perceiving suspects in more exclusionary terms increased support for treating them harshly, and for militaristic counter-terrorism policies prioritizing ingroup safety over outgroup harm. Studies 3 and 4 experimentally manipulated a racially ambiguous target's status and conformity. Results suggested that target status and conformity critically influence SDO's (status) and RWA's (conformity) effects on inclusionary versus exclusionary perceptions. PMID:24986839

  18. Impressions of people with gender-ambiguous male or female first names.

    PubMed

    McKelvie, Stuart J; Waterhouse, Kelly

    2005-10-01

    Undergraduates (12 men, 12 women) read a scenario in which they formed an impression of nine people who had left their first name on an answering machine. Participants rated the extent to which seven characteristics (Ethical, Caring, Popular, Cheerful, Successful, Masculine, Feminine) applied to people whose first names were gender-ambiguous (e.g., Chris), male (e.g., Ken) or female (e.g., Pam). People with gender-ambiguous names were rated less Ethical than those with female names, and people with gender-ambiguous names and male names were rated less Caring, less Cheerful, and less Feminine than those with female names. These results are consistent with the idea that there is a bias towards assuming that a person of unspecified sex is a male. PMID:16383061

  19. Effect of ambiguity and lexical availability on syntactic and lexical production.

    PubMed

    Ferreira, V S; Dell, G S

    2000-06-01

    Speakers only sometimes include the that in sentence complement structures like The coach knew (that) you missed practice. Six experiments tested the predictions concerning optional word mention of two general approaches to language production. One approach claims that language production processes choose syntactic structures that ease the task of creating sentences, so that words are spoken opportunistically, as they are selected for production. The second approach claims that a syntactic structure is chosen that is easiest to comprehend, so that optional words like that are used to avoid temporarily ambiguous, difficult-to-comprehend sentences. In all experiments, speakers did not consistently include optional words to circumvent a temporary ambiguity, but they did omit optional words (the complementizer that) when subsequent material was either repeated (within a sentence) or prompted with a recall cue. The results suggest that speakers choose syntactic structures to permit early mention of available material and not to circumvent disruptive temporary ambiguities. PMID:10888342

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

    PubMed Central

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

    2015-01-01

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

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

    PubMed

    Lawlor, Rob

    2016-06-01

    John Harris claims that is it 'palpable nonsense' to suggest that 'a child (or anyone) might competently consent to a treatment but not be competent to refuse it.' In 'Transitional Paternalism: How Shared Normative Powers Give Rise to the Asymmetry of Adolescent Consent and Refusal' Neil Manson aims to explain away the apparent oddness of this asymmetry of consent and refusal, by appealing to the idea of shared normative powers, presenting joint bank accounts as an example. In this article, I will argue that Manson's account fails to explain away the oddness. Rather, I will argue that there are ambiguities to which Manson has not paid sufficient attention. In fact, as odd as it may sound, I argue that Manson actually agrees with Harris (at least in relation to the asymmetry of competence). He fails to recognize that he agrees with Harris because he is not careful enough to distinguish between different asymmetries, which I have labelled the asymmetries of choice, permissibility and competence. PMID:26424104

  2. 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.

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

    PubMed

    Kopelman, L M

    1996-04-01

    The Americans With Disabilities Act (ADA) promotes social justice by protecting disabled persons from discrimination and prejudice. It seeks equality of opportunity for them and protects their well being by giving them fair access to goods, services and benefits. These rights are circumscribed in the ADA, however, by constraints of cost, efficiency, utility, and certain social mores. The ADA offers little direction about how to set priorities when these values come into conflict, or about whether equality or opportunity favors equivalent or preferential treatment for disadvantaged people. Until these ambiguities and potential value conflicts are resolved, a central moral and social problem remains unresolved: How can we demonstrate commitment to the rights and welfare of those with severe disabilities while placing fair limits upon their claims? Five special concerns are discussed: (1) eligibility and the allocation of health care; (2) the meaning of 'qualified but disabled' in employing people with mental disabilities; (3) equal opportunity and problems of envy and malingering; (4) ADA accommodation and public protection through testing and licensure; and (5) ADA protection and problems of backlash. Rather than simply wait to see what courts and administrative agencies decide, we should evaluate the moral conflicts, articulate criteria, and help make some difficult choices on morally defensible grounds. PMID:8739072

  4. Role Conflict and Ambiguity Among School District Evaluation Unit Heads.

    ERIC Educational Resources Information Center

    Grusky, Oscar

    The variation in conflict and ambiguity among a national sample of directors of school district research and evaluation units is explored. The approach developed argues that variation in evaluation unit directors' role conflict and ambiguity is a function of both school district and evaluation unit characteristics, since both sets of…

  5. Cognitive Flexibility Supports Preschoolers' Detection of Communicative Ambiguity

    ERIC Educational Resources Information Center

    Gillis, Randall; Nilsen, Elizabeth S.

    2014-01-01

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

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

    NASA Astrophysics Data System (ADS)

    Banville, Simon

    2016-05-01

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

  7. 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

  8. 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

  9. 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…

  10. 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

  11. 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…

  12. 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…

  13. How Do Adults and Children Process Referentially Ambiguous Pronouns?

    ERIC Educational Resources Information Center

    Sekerina, Irina A.; Stromswold, Karin; Hestvik, Arild

    2004-01-01

    In two eye-tracking experiments, we investigate adults' and children's on-line processing of referentially ambiguous English pronouns. Sixteen adults and 16 four-to-seven-year-olds listened to sentences with either an unambiguous reflexive ("himself") or an ambiguous pronoun ("him") and chose a picture with two characters that corresponded to…

  14. 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…

  15. Kindergarten Children Can Be Taught to Detect Lexical Ambiguities

    ERIC Educational Resources Information Center

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

    2016-01-01

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

  16. Children's Uncertainty about the Interpretation of Ambiguous Messages.

    ERIC Educational Resources Information Center

    Robinson, E. J.; Robinson, W. P.

    1983-01-01

    Investigates the ability of 63 children between five and six years of age to interpret ambiguous messages. Three studies were made into the relationship between children's uncertainty about the correctness of their interpretation of an ambiguous message and their judgment of the quality of that message. (Author/CI)

  17. Not so black and white: memory for ambiguous group members.

    PubMed

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

    2009-04-01

    Exponential increases in multiracial identities, expected over the next century, create a conundrum for perceivers accustomed to classifying people as their own- or other-race. The current research examines how perceivers resolve this dilemma with regard to the own-race bias. The authors hypothesized that perceivers are not motivated to include ambiguous-race individuals in the in-group and therefore have some difficulty remembering these individuals. 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

  18. 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…

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

    ERIC Educational Resources Information Center

    Asadollahfam, Hassan; Lotfi, Ahmad Reza

    2010-01-01

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

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

    NASA Astrophysics Data System (ADS)

    Banville, Simon

    2016-02-01

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

  1. 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…

  2. 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

  3. 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…

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

    PubMed Central

    Jiang, Xiaoming; Zhou, Xiaolin

    2015-01-01

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

  6. 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.

  7. Random unitaries give quantum expanders

    SciTech Connect

    Hastings, M. B.

    2007-09-15

    We show that randomly choosing the matrices in a completely positive map from the unitary group gives a quantum expander. We consider Hermitian and non-Hermitian cases, and we provide asymptotically tight bounds in the Hermitian case on the typical value of the second largest eigenvalue. The key idea is the use of Schwinger-Dyson equations from lattice gauge theory to efficiently compute averages over the unitary group.

  8. Covariation bias for ambiguous social stimuli in generalized social phobia.

    PubMed

    Hermann, Christiane; Ofer, Julia; Flor, Herta

    2004-11-01

    The authors investigated whether the negative interpretation bias in generalized social phobia (GSP) reflects and is maintained by illusory correlations. Participants were exposed to descriptions of ambiguous social events, situations involving fear-relevant animals and nature scenes that were randomly paired with negative, positive, or neutral emotional facial expressions. Prior to the experiment, the GSP participants overestimated the contingency social situations-negative outcome, whereas the controls judged negative outcomes as least likely. A posteriori, the GSP participants exhibited an illusory correlation specifically between social cues and negative outcomes. During the experiment, only the controls showed distorted outcome predictions for social situations. Hence, illusory correlations--possibly resulting from acquired associations between social cues and negative consequences--may contribute to a negative interpretation bias in GSP. PMID:15535796

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

    ERIC Educational Resources Information Center

    Robins, Simon

    2010-01-01

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

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

    ERIC Educational Resources Information Center

    Robins, Simon

    2010-01-01

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

  11. 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.

  12. 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

  13. 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…

  14. 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,…

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

    ERIC Educational Resources Information Center

    Abma, T. A.

    2000-01-01

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

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

    NASA Technical Reports Server (NTRS)

    Metcalf, Thomas R.

    1994-01-01

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

  17. Responses of A and B Subjects to Normal, Neurotic, Schizophrenic, and Ambiguous Communications

    ERIC Educational Resources Information Center

    Hoffnung, Robert J.; Stein, Leonard S.

    1970-01-01

    This study investigated the initial reactions of 20 A and 20 B Ss to encounter situations in which they were asked for help by four hypothetical patients communicating in normal, neurotic, schizophrenic, or ambiguous styles. The results were related to previous A and B findings. (Author)

  18. Practice makes perfect: Training the interpretation of emotional ambiguity.

    PubMed

    Clifton, Jessica L; Hedley, Sophie; Mountier, Emily; Tiszai, Boglarka; Grimshaw, Gina M

    2016-06-01

    The interpretation of emotionally ambiguous words, sentences, or scenarios can be altered through training procedures that are collectively called cognitive bias modification for interpretation (CBM-I). In three experiments, we systematically manipulated the nature of the training in order to discriminate between emotional priming and ambiguity resolution accounts of training effects. In Experiment 1 participants completed word fragments that were consistently related to either a negative or benign interpretation of an ambiguous sentence. In a subsequent semantic priming task they demonstrated an interpretation bias, in that they were faster to identify relatedness of targets that were associated with the training-congruent meaning of an emotionally ambiguous homograph. We then manipulated the training sentences to show that interpretation bias was eliminated when participants simply completed valenced word fragments following unrelated sentences (Experiment 2), or completed fragments that were related to emotional but unambiguous sentences (Experiment 3). Only when participants were required to actively resolve emotionally ambiguous sentences during training did changes in interpretation emerge at test. Findings suggest that CBM-I achieves its effects by altering a production rule that aids the selection of meaning from emotionally ambiguous alternatives, in line with an ambiguity resolution account. PMID:25807872

  19. 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

  20. 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

  1. Quadri-stability of a spatially ambiguous auditory illusion

    PubMed Central

    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

  2. Competitive helping in online giving.

    PubMed

    Raihani, Nichola J; Smith, Sarah

    2015-05-01

    Unconditional generosity in humans is a puzzle. One possibility is that individuals benefit from being seen as generous if there is competition for access to partners and if generosity is a costly-and therefore reliable-signal of partner quality [1-3]. The "competitive helping" hypothesis predicts that people will compete to be the most generous, particularly in the presence of attractive potential partners [1]. However, this key prediction has not been directly tested. Using data from online fundraising pages, we demonstrate competitive helping in the real world. Donations to fundraising pages are public and made sequentially. Donors can therefore respond to the behavior of previous donors, creating a potential generosity tournament. Our test of the competitive helping hypothesis focuses on the response to large, visible donations. We show that male donors show significantly stronger responses (by donating more) when they are donating to an attractive female fundraiser and responding to a large donation made by another male donor. The responses for this condition are around four times greater than when males give to less-attractive female (or male) fundraisers or when they respond to a large donation made by a female donor. Unlike males, females do not compete in donations when giving to attractive male fundraisers. These data suggest that males use competitive helping displays in the presence of attractive females and suggest a role for sexual selection in explaining unconditional generosity. PMID:25891407

  3. Examining the Roles of Work Autonomous and Controlled Motivations on Satisfaction and Anxiety as a Function of Role Ambiguity.

    PubMed

    Gillet, Nicolas; Fouquereau, Evelyne; Lafrenière, Marc-André K; Huyghebaert, Tiphaine

    2016-07-01

    Past research in the self-determination theory has shown that autonomous motivation is associated with positive outcomes (e.g., work satisfaction), whereas controlled motivation is related to negative outcomes (e.g., anxiety). The purpose of the present research was to examine the moderating function of role ambiguity on the relationships between work autonomous and controlled motivations on the one hand, and work satisfaction and anxiety on the other. Six hundred and ninety-eight workers (449 men and 249 women) participated in this study. Results revealed that autonomous motivation was most strongly related to satisfaction when ambiguity was low. In addition, controlled motivation was most strongly related to anxiety when ambiguity was high. In other words, the present findings suggest that the outcomes associated with each form of motivation may vary as a function of role ambiguity. The present study thus offers meaningful insights for organizations, managers, and employees. PMID:27027579

  4. Ambiguity and the image of the king.

    PubMed

    Mack, R T

    1994-01-01

    The following essay explores problems posed by a recently-published fresco (dated to the first century AD) that depicts Alexander the Great standing opposite an unknown female figure. The fresco is unusual in its use of conventional or codified figure types, in particular a widely-found statue type known as the "Alexander with the Lance," and for its placement of Alexander in anecdotal relation with a woman. While discussions of the picture thus far have tried to identify the scene depicted (by reference to histories of Alexander's life), the following analysis takes the difficulty of doing so itself as a motivated aspect of the image. I argue that the fresco's mode of representation is to bring together figure types whose conventional fields of meaning are in conflict with one another, and then to highlight this conflict in order to comment upon the fields (or figure types) themselves. In this case, the fresco's ambiguity in signification (the undecidability of its reference) enables a highly strategic critique of the "Alexander with the Lance" because the latter, as a prototypical "image of the king," depends upon the necessary and transparent extension of its signs. By virtue of the anecdotal relation between "Alexander" and the depicted female figure (an Aphrodite type) the fresco's critique reveals the close association between the claims for representation made by the image of the king and the patriarchal structures of power they seek to instantiate. The fresco thus offers remarkably direct data for understanding the intersection of representation and gender in the early Roman empire. I suggest in conclusion that because the image seems also to posit a specifically gendered (male) gaze, its critique is extended to the spectator and thereby provides data for understanding the intersection of the practice of representation (here, viewing) and gender. PMID:7798598

  5. The PCR-based detection of Trypanosoma cruzi in the faeces of Triatoma infestans fed on patients with chronic American trypanosomiasis gives higher sensitivity and a quicker result than routine xenodiagnosis.

    PubMed

    Zulantay, I; Apt, W; Gil, L C; Rocha, C; Mundaca, K; Solari, A; Sánchez, G; Rodriguez, C; Martínez, G; De Pablos, L M; Sandoval, L; Rodríguez, J; Vilchez, S; Osuna, A

    2007-12-01

    In the xenodiagnosis (XD) of American trypanosomiasis (Chagas disease), Trypanosoma cruzi in the triatomine bugs fed on the patient can now be detected using PCR (XD-PCR) as well as by microscopy (XD-M). In a study to compare XD-PCR with XD-M, triatomine bugs were fed on 50 cases of chronic American trypanosomiasis, of whom only 25 were ever found positive by XD-M. Overall, the bugs fed on 34 of the patients (all 25 cases found positive by XD-M and nine of the other patients) were found PCR-positive, giving a 330-bp fragment corresponding to part of the hyper variable region of the kinetoplast DNA of T. cruzi. Of the 25 patients who were ever found positive by XD-M, 20 gave bugs that were smear-positive on day 90 and a similar number (24; P=0.125) gave bugs that were PCR-positive at this time. On day 30, however, the bugs fed on only 11 of these 25 patients were found positive by microscopy, whereas 23 of these patients were found positive by XD-PCR (P=0.0016). Thus, not only was XD-PCR more sensitive than XD-M but it was also quicker, revealing more cases within 30 days than detected using XD-M over a period of 90 days. PMID:18028728

  6. 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

  7. 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…

  8. Imagine that! Cue-evoked representations guide rat behavior during ambiguous situations.

    PubMed

    Fast, Cynthia D; Biedermann, Traci; Blaisdell, Aaron P

    2016-04-01

    Mental imagery involves the perceptual-like experience of an event that is not physically present, or detected by the senses. Fast and Blaisdell (2011) reported that rats use the representation of an associatively retrieved event to guide behavior in ambiguous situations. Rats were reinforced for lever-pressing during 1 of 2 lights but not both lights. They were then tested with 1 light illuminated while the second light was either covered by an opaque shield (ambiguous) or uncovered and unlit (explicitly absent). Rats lever-pressed less when the second light was covered compared with unlit, suggesting that a representation of the ambiguously absent light guided their behavior. However, Dwyer and Burgess (2011) offered an alternative mechanism in which the explicit absence of a cue gains associative value during training. Covering the light at test could effectively remove these associative properties, resulting in a generalization decrement of behavior. The current experiments were designed to test contrasting predictions made by these 2 accounts. Experiment 1 empirically established that generalization decrement can occur when an element of a compound cue is presented alone at test, but this decrement is attenuated, rather than enhanced, when the absent element is covered. Experiment 2 utilized a conditioned inhibition procedure to demonstrate that rat behavior during cue ambiguity is driven by an associatively retrieved representation rather than by generalization decrement. Collectively, the results argue against a purely nonrepresentational associative account of behavior and support a role for associatively retrieved representations in rats. (PsycINFO Database Record PMID:26881900

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

    PubMed

    Rabagliati, Hugh; Snedeker, Jesse

    2013-07-01

    Words mean different things in different contexts, a phenomenon called polysemy. People talk about lines of both people and poetry, and about both long distances and long times. Polysemy lets a limited vocabulary capture a great variety of experiences, while highlighting commonalities. But how is this achieved? Are polysemous senses contextually driven modifications of core meanings, or must each sense be memorized separately? We show that participants' ability to avoid referentially ambiguous descriptions of pictures named by polysemous words provides evidence for both possibilities. When senses followed a regular pattern (e.g., animals and the foodstuffs derived from them; noisy chicken, tasty chicken), participants avoided using ambiguous labels in referentially ambiguous situations (e.g., both types of chicken were present), a result indicating that they noticed a common meaning. But when senses were idiosyncratically related (e.g., sheet of glass, drinking glass), participants frequently produced ambiguous labels, a result indicating that the meanings were separately stored. We discuss implications for the relationship between word meanings and concepts. PMID:23722978

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

    NASA Astrophysics Data System (ADS)

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

    2016-04-01

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

  11. Doppler ambiguity resolving in sparse aperture SAR imaging

    NASA Astrophysics Data System (ADS)

    Xing, Mengdao; Li, Zhengfang; Bao, Zheng; Liao, Guisheng

    2004-09-01

    The anntenna area of distributed micosateliites radar system is usually smaller than the minimum SAR antenna area constraint, and there are range-Doppler ambiguities. So one key focus of this signal processing research is to develop processing approaches that exploit the added degrees of freedom of a spatially diverse formation to resolve inherent ambiguities of this sparse aperture distributed micosateliites radar system. In the paper, a beamform processing method of three-dimensional sparse arrays is proposed to spatially null Doppler ambiguities. This method first filters out each unambiguous frequency point from ambiguous Doppler channels of a few different phase centers by using spatial filter, this processing can be regard as a space-time processing, then combines all unambiguous frequency point to a whole unambiguous Doppler band, after that, does imaging processing. Theoretical derivation, performance analysis, and simulation of this method are discussed in the paper.

  12. Administration in Higher Education: Making the Most of Ambiguity.

    ERIC Educational Resources Information Center

    Ecker, George

    1979-01-01

    In an examination of administrative organization of higher education institutions, colleges and universities are viewed as organized anarchies and loosely coupled systems. Ambiguity inherent for leadership and administration in these organizations is discussed. (SF)

  13. Intolerance of Ambiguity and Student Performance in Social Work Education.

    ERIC Educational Resources Information Center

    Davis, Liane V.; Sherman, Edmund

    1987-01-01

    Social workers must assist people in coping with complex, often apparently insoluble, problems. Data are presented on the relationship between intolerance of ambiguity and a variety of performance and preference measures of 212 social work students. (Author/MH)

  14. On the characteristics of ASCAT wind direction ambiguities

    NASA Astrophysics Data System (ADS)

    Lin, W.; Portabella, M.; Stoffelen, A.; Verhoef, A.

    2013-04-01

    The inversion of the Advanced Scatterometer (ASCAT) backscatter measurement triplets generally leads to two wind ambiguities with similar wind speed values and opposite wind directions. However, for up-, down- and crosswind (with respect to the mid-beam azimuth direction) cases, the inversion often leads to three or four wind solutions. In most of such cases, the inversion residuals or maximum likelihood estimators (MLEs) of the third and fourth solutions (i.e. high-rank solutions) are substantially higher than those of the first two (low-rank) ambiguities. This indicates a low probability for the high-rank solutions and thus essentially dual ambiguity. This paper investigates the characteristics of ASCAT high-rank wind solutions under different conditions with the objective of developing a method for rejecting the spurious high-rank solutions. The implementation of this rejection procedure improves the effectiveness of the ASCAT wind quality control (QC) and ambiguity removal procedures.

  15. On the characteristics of ASCAT wind direction ambiguities

    NASA Astrophysics Data System (ADS)

    Lin, W.; Portabella, M.; Stoffelen, A.; Verhoef, A.

    2012-12-01

    The inversion of the Advanced Scatterometer (ASCAT) backscatter measurement triplets generally leads to two wind ambiguities with similar wind speed values and opposite wind directions. However, for up-, down- and cross-wind (with respect to the mid beam azimuth direction) cases, the inversion often leads to three or four wind solutions. In most of such cases, the inversion residual or maximum likelihood estimator (MLE) of the 3rd and 4th solutions (i.e. high-rank solutions) are substantially higher than those of the first two (low rank) ambiguities, indicating a low probability of the former and thus essentially dual ambiguity. This paper investigates the characteristics of ASCAT high-rank wind solutions under different conditions with the objective to develop a method for rejecting the spurious high-rank solutions. The implementation of this rejection procedure improves the effectiveness of the ASCAT wind quality control (QC) and ambiguity removal procedures.

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

    PubMed

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

    2013-06-01

    Language is rife with ambiguity. Do children and adults meet this challenge in similar ways? Recent work suggests that while adults resolve syntactic ambiguities by integrating a variety of cues, children are less sensitive to top-down evidence. We test whether this top-down insensitivity is specific to syntax or a general feature of children's linguistic ambiguity resolution by evaluating whether children rely largely or completely on lexical associations to resolve lexical ambiguities (e.g., the word swing primes the baseball meaning of bat) or additionally integrate top-down global plausibility. Using a picture choice task, we compared 4-year-olds' ability to resolve polysemes and homophones with a Bayesian algorithm reliant purely on lexical associations and found that the algorithm's power to predict children's choices was limited. A 2nd experiment confirmed that children override associations and integrate top-down plausibility. We discuss this with regard to models of psycholinguistic development. PMID:22229852

  17. Pediatric residents' response to ambiguous words about child discipline and behavior.

    PubMed

    Clayman, Marla L; Wissow, Lawrence S

    2004-10-01

    Frequently, doctors have been noted to seemingly ignore or brush off patients' bids to discuss sensitive issues. In some of these cases, however, apparent ignoring could be the result of the doctor mistakenly interpreting the meaning of potentially ambiguous terms used by the patient. This study demonstrates the frequency with which parents use and pediatricians clarify ambiguous terms describing child behavior and physical punishment. Sixty-one (26%) of 234 audiotapes from a systematic cross-sectional sample of non-urgent visits with pediatric residents included at least one episode in which such words were used by a parent. Discussion following each use was classified as: (a) clarifying its meaning, (b) discussing without clarification, (c) ignoring the use of the word, or (d) contradicting the negative attribution. In 61 visits, the parent or child was the first to use the potentially ambiguous term. Physicians clarified 7 (11%) of the terms, ignored 23 (38%), contradicted 7 (11%), and discussed without clarification 24 (39%). Clarifying and contradicting were associated with a shorter doctor-patient relationship than ignoring or discussing without clarification. Doctors who sought clarification were the least dominant. A non-dismissive response to ambiguous words may be a marker for both the stage of the doctor-patient relationship and a doctor's overall interactive style. Considering clarification may be helpful in understanding doctors' responses to patients' cues. PMID:15476985

  18. Biasing the perception of ambiguous vocal affect: a TMS study on frontal asymmetry.

    PubMed

    Donhauser, Peter W; Belin, Pascal; Grosbras, Marie-Hélène

    2014-07-01

    Several sources of evidence point toward a link between asymmetry of prefrontal brain activity and approach-withdrawal tendencies. Here, we tested the causal nature of this link and examined if the categorization of an ambiguous approach- or withdrawal-related vocal signal can be biased by manipulating left and right frontal neural activity. We used voice morphing of affective non-verbal vocalizations to create individually tailored affectively ambiguous stimuli on an Anger-Fear continuum-two emotions that represent extremes on the approach-withdrawal dimension. We tested perception of these stimuli after 10 min of low-frequency repetitive transcranial magnetic stimulation over left or right dorsolateral prefrontal cortex or over the vertex (control), a technique that has transient inhibitory effects on the targeted brain region. As expected, ambiguous stimuli were more likely perceived as expressing Anger (approach) than Fear (withdrawal) after right prefrontal compared with left prefrontal or control stimulation. These results provide the first evidence that the manipulation of asymmetrical activity in prefrontal cortex can change the explicit categorization of ambiguous emotional signals. PMID:23784072

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

    PubMed

    Logačev, Pavel; Vasishth, Shravan

    2016-03-01

    Traxler, Pickering, and Clifton (1998) found that ambiguous sentences are read faster than their unambiguous counterparts. This so-called ambiguity advantage has presented a major challenge to classical theories of human sentence comprehension (parsing) because its most prominent explanation, in the form of the unrestricted race model (URM), assumes that parsing is non-deterministic. Recently, Swets, Desmet, Clifton, and Ferreira (2008) have challenged the URM. They argue that readers strategically underspecify the representation of ambiguous sentences to save time, unless disambiguation is required by task demands. When disambiguation is required, however, readers assign sentences full structure-and Swets et al. provide experimental evidence to this end. On the basis of their findings, they argue against the URM and in favor of a model of task-dependent sentence comprehension. We show through simulations that the Swets et al. data do not constitute evidence for task-dependent parsing because they can be explained by the URM. However, we provide decisive evidence from a German self-paced reading study consistent with Swets et al.'s general claim about task-dependent parsing. Specifically, we show that under certain conditions, ambiguous sentences can be read more slowly than their unambiguous counterparts, suggesting that the parser may create several parses, when required. Finally, we present the first quantitative model of task-driven disambiguation that subsumes the URM, and we show that it can explain both Swets et al.'s results and our findings. PMID:25823920

  20. Mentalizing under Uncertainty: Dissociated Neural Responses to Ambiguous and Unambiguous Mental State Inferences

    PubMed Central

    Mitchell, Jason P.

    2010-01-01

    The ability to read the minds of others (i.e., to mentalize) requires that perceivers understand a wide range of different kinds of mental states, including not only others’ beliefs and knowledge but also their feelings, desires, and preferences. Moreover, although such inferences may occasionally rely on observable features of a situation, perceivers more typically mentalize under conditions of “uncertainty,” in which they must generate plausible hypotheses about a target's mental state from ambiguous or otherwise underspecified information. Here, we use functional neuroimaging to dissociate the neural bases of these 2 distinct social–cognitive challenges: 1) mentalizing about different types of mental states (beliefs vs. preferences) and 2) mentalizing under conditions of varying ambiguity. Although these 2 aspects of mentalizing have typically been confounded in earlier research, we observed a double dissociation between the brain regions sensitive to type of mental state and ambiguity. Whereas ventral and dorsal aspects of medial prefrontal cortex responded more during ambiguous than unambiguous inferences regardless of the type of mental state, the right temporoparietal junction was sensitive to the distinction between beliefs and preferences irrespective of certainty. These results underscore the emerging consensus that, rather than comprising a single mental operation, social cognition makes flexible use of different processes as a function of the particular demands of the social context. PMID:19478034

  1. 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.

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

    PubMed

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

    2015-01-01

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

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

    PubMed Central

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

    2015-01-01

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

  4. Mediotemporal contributions to semantic processing: fMRI evidence from ambiguity processing during semantic context verification.

    PubMed

    Hoenig, Klaus; Scheef, Lukas

    2005-01-01

    The medial temporal lobe (MTL) is well known to be crucial for various types of memory; however, controversy remains as to which of its substructures contribute to semantic processing and, if so, to what extent. The current study addresses the issue of MTL contributions to semantic processing during lexico-semantic ambiguity processing by using functional magnetic resonance imaging (fMRI) in combination with a context verification task (CVT). The CVT required decisions on the semantic fit of congruent and incongruent target words to the overall meaning of preceding sentential contexts with and without semantic ambiguity. In two of the four experimental conditions (congruent homographic, incongruent homographic), target decisions were critically dependent on the successful processing of prior sentence-final lexico-semantic ambiguity. Semantic context verification per se evidenced bilateral activations of the hippocampus that were part of a functional network including inferior prefrontal and superior parietal cortices. Commonalities in activation differences pertaining to the specific cognitive component of lexico-semantic ambiguity processing were found in a left temporal lobe network that comprised activation foci in the temporal pole, the parahippocampal and fusiform gyri. The present results suggest that the hippocampus may well contribute to semantic processing, namely by a mnemonic function that serves to link the target meaning representation with the meaning of a prior sentence context. Contrary to previous reports from human lesion studies, the present findings further suggest, that the specific cognitive component of lexico-semantic ambiguity processing is neither dependent on the hippocampus nor exclusively subserved by the temporal pole, but also recruits an associative semantic memory function from the parahippocampal gyrus as well as a more general (bottom-up) semantic function from the fusiform gyrus. PMID:15884095

  5. Ambiguous Cylinders: A New Class of Solid That Evokes Anomalous Perception.

    PubMed

    Sugihara, Kokichi

    2015-01-01

    We have discovered a new type of optical illusion in which a single solid generates impressions of two quite different cylinders when it is seen from two special viewpoints. By positioning a solid and a mirror in such a way that the two special viewpoints can be experienced simultaneously, the viewer sees both the solid itself and its mirror image, but as apparently different objects. From this, the viewer understands logically that what he/she is perceiving is different from the real shape of the solid, but the visual system of the viewer does not correct the misperception of the solid's shape. In this sense, this anomalous perception belongs to the class of optical illusions, and we are naming it the ambiguous cylinder illusion. The ambiguous cylinder illusion can be explained as the result of an interaction between depth ambiguity in a single image and a human preference for a rectangular structure. From a mathematical point of view, a single image cannot uniquely specify the three-dimensional shape of an object appearing in the image, because the image does not convey depth information, and hence there is ambiguity in the object. From a psychological point of view, on the other hand, the human visual system prefers certain interpretations more strongly than other interpretations. In particular, if the solid is composed of planar faces, then the system seems to prefer the interpretation of a rectangular structure to other interpretations. In the case of an image of a cylindrical object, the human visual system seems to consider that the object is generated by cutting a cylinder with a plane perpendicular to the axis of the cylinder. We will show that ambiguous cylinders can be created successfully on the basis of this hypothesis. Meeting abstract presented at VSS 2015. PMID:26326418

  6. 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

  7. Integer ambiguity resolution in precise point positioning: method comparison

    NASA Astrophysics Data System (ADS)

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

    2010-09-01

    Integer ambiguity resolution at a single receiver can be implemented by applying improved satellite products where the fractional-cycle biases (FCBs) have been separated from the integer ambiguities in a network solution. One method to achieve these products is to estimate the FCBs by averaging the fractional parts of the float ambiguity estimates, and the other is to estimate the integer-recovery clocks by fixing the undifferenced ambiguities to integers in advance. In this paper, we theoretically prove the equivalence of the ambiguity-fixed position estimates derived from these two methods by assuming that the FCBs are hardware-dependent and only they are assimilated into the clocks and ambiguities. To verify this equivalence, we implement both methods in the Position and Navigation Data Analyst software to process 1 year of GPS data from a global network of about 350 stations. The mean biases between all daily position estimates derived from these two methods are only 0.2, 0.1 and 0.0 mm, whereas the standard deviations of all position differences are only 1.3, 0.8 and 2.0 mm for the East, North and Up components, respectively. Moreover, the differences of the position repeatabilities are below 0.2 mm on average for all three components. The RMS of the position estimates minus those from the International GNSS Service weekly solutions for the former method differs by below 0.1 mm on average for each component from that for the latter method. Therefore, considering the recognized millimeter-level precision of current GPS-derived daily positions, these statistics empirically demonstrate the theoretical equivalence of the ambiguity-fixed position estimates derived from these two methods. In practice, we note that the former method is compatible with current official clock-generation methods, whereas the latter method is not, but can potentially lead to slightly better positioning quality.

  8. 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

  9. Phase ambiguity solution with the Pyramid Phasing Sensor

    NASA Astrophysics Data System (ADS)

    Pinna, E.; Esposito, S.; Puglisi, A.; Pieralli, F.; Myers, R. M.; Busoni, L.; Tozzi, A.; Stefanini, P.

    2006-06-01

    In the technological development for the ELTs, one of the key activities is the phasing and alignment of the primary mirror segments. To achieve the phasing accuracy of a small fraction of the wavelength, an optical sensor is required. In 2005 has been demonstrated that the Pyramid Wavefront Sensor can be employed in closed loop to correct simultaneously piston, tip and tilt errors of segmented mirror. The Pyramid Phasing Sensor (PYPS) is based on the sensing of phase step on the segment edges; this kind of phasing sensors have the common limitation of the signal ambiguity induced by the phase periodicity of πδ/λ on the mirror surface step δ, when the wavelength λ is used for the sensing. In this paper we briefly describe three different techniques that allow to solve the phase ambiguity with PYPS. As first we present experimental results on the two wavelengths closed loop procedure proposed by Esposito in 2001; in the laboratory test the multi-wavelength procedure allowed to exceed the sensor capture range of +/-λ/2 and simultaneously retrieve the differential piston of the 32 mirror segments starting from random positions in a 3.2 λ wavefront range, the maximum allowed by the mirror stroke. Then we propose two new techniques based respectively on the segment and wavelength sweep. The Segment Sweep Technique (SST) has been successfully applied during the experimental tests of PYPS at the William Herschel Telescope, when 13 segments of the NAOMI DM has been phased starting from a random position in a 15λ range. The Wavelength Sweep Technique (WST) has been subject of preliminary tests in the Arcetri laboratories in order to prove the concept. Each technique has different capture range, accuracy and operation time, so that each can solve different tasks required to an optical phasing sensor in the ELT application. More in detail the WST and SST could be used combined for the first mirror phasing when the calibration required for the closed loop operations are not yet available. Then the closed loop capture range can be extended from +/-λ/2 to +/-10λ with the multi-wavelength closed loop technique.

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

    ERIC Educational Resources Information Center

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

    2005-01-01

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

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

    NASA Technical Reports Server (NTRS)

    Berner, Jeff; Kinman, Peter

    2004-01-01

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

  12. Auditory Scene Analysis: The Sweet Music of Ambiguity

    PubMed Central

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

    2011-01-01

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

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

    PubMed

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

    2014-11-01

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

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

    PubMed Central

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

    2014-01-01

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

  15. Sexual picture processing interferes with decision-making under ambiguity.

    PubMed

    Laier, Christian; Pawlikowski, Mirko; Brand, Matthias

    2014-04-01

    Many people watch sexually arousing material on the Internet in order to receive sexual arousal and gratification. When browsing for sexual stimuli, individuals have to make several decisions, all possibly leading to positive or negative consequences. Decision-making research has shown that decisions under ambiguity are influenced by consequences received following earlier decisions. Sexual arousal might interfere with the decision-making process and should therefore lead to disadvantageous decision-making in the long run. In the current study, 82 heterosexual, male participants watched sexual pictures, rated them with respect to sexual arousal, and were asked to indicate their current level of sexual arousal before and following the sexual picture presentation. Afterwards, subjects performed one of two modified versions of the Iowa Gambling Task in which sexual pictures were displayed on the advantageous and neutral pictures on the disadvantageous card decks or vice versa (n = 41/n = 41). Results demonstrated an increase of sexual arousal following the sexual picture presentation. Decision-making performance was worse when sexual pictures were associated with disadvantageous card decks compared to performance when the sexual pictures were linked to the advantageous decks. Subjective sexual arousal moderated the relationship between task condition and decision-making performance. This study emphasized that sexual arousal interfered with decision-making, which may explain why some individuals experience negative consequences in the context of cybersex use. PMID:23733155

  16. Assumptions and ambiguities in nonplanar acoustic soliton theory

    SciTech Connect

    Verheest, Frank; School of Chemistry and Physics, University of KwaZulu-Natal, Durban 4000 ; Hellberg, Manfred A.

    2014-02-15

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

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

    PubMed

    Webman-Shafran, Ronit; Fodor, Janet Dean

    2016-06-01

    We investigated the processing of ambiguous double-PP constructions in Hebrew. Selection restrictions forced the first prepositional phrase (PP1) to attach low, but PP2 could attach maximally high to VP or maximally low to the NP inside PP1. A length contrast in PP2 was also examined. This construction affords more potential locations for prosodic boundaries, and has a sharper structural contrast between the two attachment sites, than the single-PP construction which has yielded mixed results in previous work. A combined production-comprehension task showed more productions of pre-PP2 prosodic boundaries for long-PP2 than short-PP2. In comprehension, high PP2-attachment was favored by a prosodic boundary before PP2, regardless of PP2 length. This study provides performance data supporting the interplay of phrase lengths with structure-sensitivity as posited in the linguistics literature on the syntax-prosody interface, and supports the claim that readers are sensitive to the structural implications of the prosody they project onto sentences. PMID:25753647

  18. Spontaneous giving and calculated greed.

    PubMed

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

    2012-09-20

    Cooperation is central to human social behaviour. However, choosing to cooperate requires individuals to incur a personal cost to benefit others. Here we explore the cognitive basis of cooperative decision-making in humans using a dual-process framework. We ask whether people are predisposed towards selfishness, behaving cooperatively only through active self-control; or whether they are intuitively cooperative, with reflection and prospective reasoning favouring 'rational' self-interest. To investigate this issue, we perform ten studies using economic games. We find that across a range of experimental designs, subjects who reach their decisions more quickly are more cooperative. Furthermore, forcing subjects to decide quickly increases contributions, whereas instructing them to reflect and forcing them to decide slowly decreases contributions. Finally, an induction that primes subjects to trust their intuitions increases contributions compared with an induction that promotes greater reflection. To explain these results, we propose that cooperation is intuitive because cooperative heuristics are developed in daily life where cooperation is typically advantageous. We then validate predictions generated by this proposed mechanism. Our results provide convergent evidence that intuition supports cooperation in social dilemmas, and that reflection can undermine these cooperative impulses. PMID:22996558

  19. Giving Corrective Feedback: A Decisional Analysis.

    ERIC Educational Resources Information Center

    Latting, Jean Kantambu

    1992-01-01

    Notes advantages of effective feedback in improving quantity and quality of employees' performance. Presents set of guidelines for giving corrective feedback in four categories: deciding whether to give corrective feedback; deciding what to say when giving feedback; deciding how and when to give feedback; and deciding how to handle receiver's

  20. 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.

  1. Giving curriculum planners an edge

    PubMed Central

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

    2015-01-01

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

  2. Determining the point of subjective ambiguity of ambiguous biological-motion figures with perspective cues.

    PubMed

    Schouten, Ben; Verfaillie, Karl

    2010-02-01

    Orthographic frontal/back projections of biological-motion figures are bistable: The point-light figure in principle can be perceived either as facing toward the viewer or as facing away from the viewer. Some point-light actions--for example, walking--elicit a strong "facing bias": Despite the absence of objective cues to depth, observers tend to interpret the figure as facing toward the viewer in most of the cases. In this article, we present and experimentally validate a technique that affords full experimental control of the perceived in-depth orientation of point-light figures. We demonstrate that by parametrically manipulating the amount of perspective information in the stimulus, it is possible to obtain any desired level of subjective ambiguity. Directions for future research, in which this technique can be fruitfully implemented, are suggested. Program code of a demo is provided that can be modified easily for program code of new experiments. The demo and QuickTime movie files illustrating our perspective manipulation technique may be downloaded from http://brm.psychonomic-journals.org/content/supplemental. PMID:20160296

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

    NASA Astrophysics Data System (ADS)

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

    2015-11-01

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

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

    PubMed

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

    2014-01-01

    We studied the eye movement parameters during reading of syntactically ambiguous sentences with feminine relative clause in Russian language. A priori difficulties of sentence structural analysis results in increase of time spent on reading as opposed to reading control sentences (unambiguous). Such a delay is caused by an increase of frequency of regressions (backward saccades) which are executed for rereading an ambiguous fragment ofsentence. This fact in turn leads to an increase in number of fixations and their duration. The total reading time for particular words composing the ambiguous fragment of sentence depended on disambiguation result (relative clause attachment, early/late closure). In case of early closure (when the subject attached relative clause to first noun) the total reading time for this noun exceeded one for second noun. In case of late closure (when the subject attached relative clause to second noun) the total reading time for both nouns didn't differ. Our results indicate that early closure domination in Russian language determines the greater total reading time for first noun of nominal group associated with relative clause. PMID:25711096

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

    PubMed Central

    Almeida, Aitor; López-de-Ipiña, Diego

    2012-01-01

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

  6. Advice on the management of ambiguous genitalia to a young endocrinologist from experienced clinicians.

    PubMed

    Wilson, Jean D; Rivarola, Marco A; Mendonca, Berenice B; Warne, Garry L; Josso, Nathalie; Drop, Stenvert L S; Grumbach, Melvin M

    2012-10-01

    The birth of a child with ambiguous genitalia is a challenging and distressing event for the family and physician and one with life-long consequences. Most disorders of sexual differentiation (DSD) associated with ambiguous genitalia are the result either of inappropriate virilization of girls or incomplete virilization of boys. It is important to establish a diagnosis as soon as possible, for psychological, social, and medical reasons, particularly for recognizing accompanying life-threatening disorders such as the salt-losing form of congenital adrenal hyperplasia. In most instances, there is sufficient follow-up data so that making the diagnosis also establishes the appropriate gender assignment (infants with congenital adrenal hyperplasia, those with androgen resistance syndromes), but some causes of DSD such as steroid 5α-reductase 2 deficiency and 17β-hydroxysteroid dehydrogenase deficiency are associated with frequent change in social sex later in life. In these instances, guidelines for sex assignment are less well established. PMID:23044870

  7. Increasing recognition of happiness in ambiguous facial expressions reduces anger and aggressive behavior.

    PubMed

    Penton-Voak, Ian S; Thomas, Jamie; Gage, Suzanne H; McMurran, Mary; McDonald, Sarah; Munafò, Marcus R

    2013-05-01

    The ability to identify emotion in other people is critical to social functioning. In a series of experiments, we explored the relationship between recognition of emotion in ambiguous facial expressions and aggressive thoughts and behavior, both in healthy adults and in adolescent youth at high risk of criminal offending and delinquency. We show that it is possible to experimentally modify biases in emotion recognition to encourage the perception of happiness over anger in ambiguous expressions. This change in perception results in a decrease in self-reported anger and aggression in healthy adults and high-risk youth, respectively, and also in independently rated aggressive behavior in high-risk youth. We obtained similar effects on mood using two different techniques to modify biases in emotion perception (feedback-based training and visual adaptation). These studies provide strong evidence that emotion processing plays a causal role in anger and the maintenance of aggressive behavior. PMID:23531485

  8. 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…

  9. 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.…

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

    ERIC Educational Resources Information Center

    McArthur, John

    2011-01-01

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

  11. The Control over Marginality. Structural Integration of Ambiguity.

    ERIC Educational Resources Information Center

    Kruithof, C. L.

    1990-01-01

    Examines structural marginality on two levels, substantial and functional. Argues that fundamental organizational framework of economic and political institutions determines the relationship between substantial and functional marginality. Explores the ambiguity involved when dominant society defines and controls marginal groups and individuals.

  12. Children's Interpretation of Ambiguous Focus in Sentences with "Only"

    ERIC Educational Resources Information Center

    Paterson, Kevin B.; Liversedge, Simon P.; White, Diane; Filik, Ruth; Jaz, Kristina

    2006-01-01

    We report 3 studies investigating children's and adults' interpretation of ambiguous focus in sentences containing the focus-sensitive quantifier only. In each experiment, child and adult participants compared sentences with only in a preverbal position and counterpart sentences without only against a series of pictures depicting events that…

  13. Prosody and the Interpretation of Hierarchically Ambiguous Discourse

    ERIC Educational Resources Information Center

    Tyler, Joseph

    2014-01-01

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

  14. 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

  15. 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…

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

    ERIC Educational Resources Information Center

    Howard, Jenna

    2006-01-01

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

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

    ERIC Educational Resources Information Center

    Clarà, Marc

    2015-01-01

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

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

    ERIC Educational Resources Information Center

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

    2016-01-01

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

  19. Trait Ambiguity and Controllability in Evaluations of Self and Others.

    ERIC Educational Resources Information Center

    Powell, Jack L.; Jacobson, Alan S.

    Research has found that most people tend to rate themselves as above average on desirable skills or qualities and below average on undesirable qualities. Two factors have been found to influence this self-serving bias: (1) controllability or the perceived control one has over developing a trait; and (2) trait ambiguity in which a positive trait

  20. 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,"…

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

    ERIC Educational Resources Information Center

    Goodrich Smith, Whitney; Hudson Kam, Carla L.

    2015-01-01

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

  2. Bilingual Education: The Problem of Ambiguity and Poor Professional Development.

    ERIC Educational Resources Information Center

    Pena, Griselda

    This paper examines the ambiguity in defining terms within the field of bilingual education, noting problems with poor professional development available to teachers selected to participate in bilingual education programs. The first section discusses terminology within bilingual education programs, focusing on the following: transitional bilingual…

  3. 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…

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

    NASA Astrophysics Data System (ADS)

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

    1988-10-01

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

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

    ERIC Educational Resources Information Center

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

    2014-01-01

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

  6. 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…

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

    ERIC Educational Resources Information Center

    Taibu, Rex; Rudge, David; Schuster, David

    2015-01-01

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

  8. 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…

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

    ERIC Educational Resources Information Center

    Roth, Lane

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

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

    ERIC Educational Resources Information Center

    DeWaele, Jean-Marc; Wei, Li

    2013-01-01

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

  11. 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…

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

    ERIC Educational Resources Information Center

    McArthur, John

    2011-01-01

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

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

    ERIC Educational Resources Information Center

    Taibu, Rex; Rudge, David; Schuster, David

    2015-01-01

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

  14. 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…

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

    ERIC Educational Resources Information Center

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

    2012-01-01

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

  16. Fear of Success Revisited: Introducing an Ambiguous Cue.

    ERIC Educational Resources Information Center

    Gravenkemper, Stephen A.; Paludi, Michele A.

    1983-01-01

    M.S. Horner has been criticized for defining "success" to her subjects in her research on fear-of-success. The present study, which provided an ambiguous verbal lead, showed low incidence of fear-of-success, because subjects themselves were allowed to define "success." (GC)

  17. 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…

  18. Knowing what a novel word is not: Two-year-olds ‘listen through’ ambiguous adjectives in fluent speech

    PubMed Central

    Thorpe, Kirsten; Fernald, Anne

    2011-01-01

    Three studies investigated how 24-month-olds and adults resolve temporary ambiguity in fluent speech when encountering prenominal adjectives potentially interpretable as nouns. Children were tested in a looking-while-listening procedure to monitor the time course of speech processing. In Experiment 1, the familiar and unfamiliar adjectives preceding familiar target nouns were accented or deaccented. Target word recognition was disrupted only when lexically ambiguous adjectives were accented like nouns. Experiment 2 measured the extent of interference experienced by children when interpreting prenominal words as nouns. In Experiment 3, adults used prosodic cues to identify the form class of adjective/noun homophones in string-identical sentences before the ambiguous words were fully spoken. Results show that children and adults use prosody in conjunction with lexical and distributional cues to ‘listen through’ prenominal adjectives, avoiding costly misinterpretation. PMID:16125688

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

    NASA Astrophysics Data System (ADS)

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

    2012-04-01

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

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

    PubMed Central

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

    2015-01-01

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

  1. Benefits of using culturally unfamiliar stimuli in ambiguous emotion identification: A cross-cultural study.

    PubMed

    Koelkebeck, Katja; Kohl, Waldemar; Luettgenau, Julia; Triantafillou, Susanna; Ohrmann, Patricia; Satoh, Shinji; Minoshita, Seiko

    2015-07-30

    A novel emotion recognition task that employs photos of a Japanese mask representing a highly ambiguous stimulus was evaluated. As non-Asians perceive and/or label emotions differently from Asians, we aimed to identify patterns of task-performance in non-Asian healthy volunteers with a view to future patient studies. The Noh mask test was presented to 42 adult German participants. Reaction times and emotion attribution patterns were recorded. To control for emotion identification abilities, a standard emotion recognition task was used among others. Questionnaires assessed personality traits. Finally, results were compared to age- and gender-matched Japanese volunteers. Compared to other tasks, German participants displayed slowest reaction times on the Noh mask test, indicating higher demands of ambiguous emotion recognition. They assigned more positive emotions to the mask than Japanese volunteers, demonstrating culture-dependent emotion identification patterns. As alexithymic and anxious traits were associated with slower reaction times, personality dimensions impacted on performance, as well. We showed an advantage of ambiguous over conventional emotion recognition tasks. Moreover, we determined emotion identification patterns in Western individuals impacted by personality dimensions, suggesting performance differences in clinical samples. Due to its properties, the Noh mask test represents a promising tool in the differential diagnosis of psychiatric disorders, e.g. schizophrenia. PMID:25933477

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

    PubMed

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

    2016-02-01

    The individual tendency to interpret ambiguous situations negatively is associated with mental disorders. Interpretation biases are already evident during adolescence and due to the greater plasticity of the developing brain it may be easier to change biases during this time. We investigated in healthy adolescents and adults whether stabilizing memories of positive or negative scenes modulates the later interpretation of similar scenes. In the evening, participants learnt associations between ambiguous pictures and words that disambiguate the valence of the pictures in a positive or negative direction. Half of the words were acoustically presented (i.e. cued) during post-learning sleep which is known to benefit memory consolidation by inducing reactivation of learned information. Cued compared to un-cued stimuli were remembered better the next morning. Importantly, cueing positively disambiguated pictures resulted in more positive interpretations whereas cueing negatively disambiguated pictures led to less positive interpretations of new ambiguous pictures with similar contents the next morning. These effects were not modulated by participants' age indicating that memory cueing was as efficient in adolescents as in adults. Our findings suggest that memory cueing during sleep can modify interpretation biases by benefitting memory stabilization and generalization. Implications for clinical settings are discussed. PMID:26588358

  3. Ambiguity Function of the Transmit Beamspace-Based MIMO Radar

    NASA Astrophysics Data System (ADS)

    Li, Yongzhe; Vorobyov, Sergiy A.; Koivunen, Visa

    2015-09-01

    In this paper, we derive an ambiguity function (AF) for the transmit beamspace (TB)-based multipleinput multiple-output (MIMO) radar for the case of far-field targets and narrow-band waveforms. The effects of transmit coherent processing gain and waveform diversity are incorporated into the AF definition. To cover all the phase information conveyed by different factors, we introduce the equivalent transmit phase centers. The newly defined AF serves as a generalized AF form for which the phased-array (PA) and traditional MIMO radar AFs are important special cases. We establish relationships among the defined TB-based MIMO radar AF and the existing AF results including the Woodward's AF, the AFs defined for the traditional colocated MIMO radar, and also the PA radar AF, respectively. Moreover, we compare the TB-based MIMO radar AF with the square-summation-form AF definition and identify two limiting cases to bound its 'clear region' in Doppler-delay domain that is free of sidelobes. Corresponding bounds for these two cases are derived, and it is shown that the bound for the worst case is inversely proportional to the number of transmitted waveforms K, whereas the bound for the best case is independent of K. The actual 'clear region' of the TB-based MIMO radar AF depends on the array configuration and is in between of the worst- and best-case bounds. We propose a TB design strategy to reduce the levels of the AF sidelobes, and show in simulations that proper design of the TB matrix leads to reduction of the relative sidelobe levels of the TB-based MIMO radar AF.

  4. Anisotropy in an ambiguous kinetic depth effect

    NASA Technical Reports Server (NTRS)

    Mulligan, Jeffrey B.

    1992-01-01

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

  5. Ambiguity produces attention shifts in category learning.

    PubMed

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

    2016-04-01

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

  6. 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

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

    PubMed

    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

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

    PubMed

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

    2014-09-18

    Previous neuroimaging studies showed that correct resolution of lexical ambiguity relies on the integrity of prefrontal and inferior parietal cortices. Whereas prefrontal brain areas were associated with executive control over semantic selection, inferior parietal areas were linked with access to modality-independent representations of semantic memory. Yet insufficiently understood is the contribution of subcortical structures in ambiguity processing. Patients with disturbed basal ganglia function such as Parkinson׳s disease (PD) showed development of discourse comprehension deficits evoked by lexical ambiguity. To further investigate the engagement of cortico-subcortical networks functional Magnetic Resonance Imaging (fMRI) was monitored during ambiguity resolution in eight early PD patients without dementia and 14 age- and education-matched controls. Participants were required to relate meanings to a lexically ambiguous target (homonym). Each stimulus consisted of two words arranged on top of a screen, which had to be attributed to a homonym at the bottom. Brain activity was found in bilateral inferior parietal (BA 39), right middle temporal (BA 21/22), left middle frontal (BA 10) and bilateral inferior frontal areas (BA 45/46). Extent and amplitude of activity in the angular gyrus changed depending on semantic association strength that varied between conditions. Less activity in the left caudate was associated with semantic integration deficits in PD. The results of the present study suggest a relationship between subtle language deficits and early stages of basal ganglia dysfunction. Uncovering impairments in ambiguity resolution may be of future use in the neuropsychological assessment of non-motor deficits in PD. PMID:24992291

  9. Perceived ambiguity about cancer prevention recommendations: associations with cancer-related perceptions and behaviours in a US population survey

    PubMed Central

    Han, Paul K. J.; Moser, Richard P.; Klein, William M. P.

    2014-01-01

    Background Health information reaching the public today is often characterized by what decision theorists have termed ‘ambiguity’ – i.e. uncertainty regarding the information’s reliability, credibility or adequacy. This is a critical problem, as growing research suggests that ambiguity has important effects–promoting pessimistic judgments about risks and potential outcomes of risk-reducing behaviours, and lowering adoption of these behaviours. However, little is known about the public’s perceptions of ambiguity in the health information domain, the effects of these perceptions, and the factors that influence these effects. Objective To examine associations between perceived ambiguity regarding cancer prevention recommendations and prevention-related perceptions and behaviours, and to explore how these associations differ by cancer type. Study design and participants Cross-sectional analysis of data on 4070 adults participating in the 2005 US Health Information National Trends Survey. Main variables and outcome measures We examined associations between perceived ambiguity about colon, skin and lung cancer prevention recommendations and two main outcome variables: (i) risk-related cognitions (perceived cancer risk and preventability, cancer-related worry) and (ii) risk-modifying behaviours (colon cancer screening, sunscreen use and smoking abstinence). Results Perceived ambiguity was inversely associated with perceptions of the preventability of all three cancers, and with cancer-specific risk-modifying behaviours including sigmoidoscopy–colonoscopy testing, sunscreen use and smoking abstinence. Relationships with cancer risk perceptions and worry varied across different cancer types. Conclusions Perceived ambiguity about cancer prevention recommendations has significant and predictable associations with cancer prevention-related cognitions and behaviours, and some associations differ by cancer type. These findings have implications for future research and communication efforts. PMID:17986069

  10. 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

  11. Cesare Lombroso: Methodological ambiguities and brilliant intuitions.

    PubMed

    Gatti, Uberto; Verde, Alfredo

    2012-01-01

    This paper on Cesare Lombroso aims to assess his contribution to the criminological sciences. Although much praised worldwide, Lombroso was also the target of scathing criticism and unmitigated condemnation. Examination of Lombroso's method of data collection and analysis reveals his weakness. Indeed, his approach was extremely naive, simplistic and uncritical, aimed at irrefutably demonstrating the hypotheses that he championed, without exercising the methodological caution that was already beginning to characterize scientific research in his day. However, we must acknowledge that his biological theories of crime are undergoing new developments as a result of the recent success of biological psychiatry. On the other hand we should recognize that his work was not limited to his biological central theory; rather, it covered a range of cues and concepts, for the most part ignored, that demonstrate his interest in the economic, cultural and social factors that impact on crime. For these reasons, Lombroso appears to have anticipated many modern conceptions regarding delinquent behavior and criminal justice, such as those of restorative justice, the so-called "situational" theories of criminal behavior and white collar crime. PMID:22154472

  12. PICS-Ord: unlimited coding of ambiguous regions by pairwise identity and cost scores ordination

    PubMed Central

    2011-01-01

    Background We present a novel method to encode ambiguously aligned regions in fixed multiple sequence alignments by 'Pairwise Identity and Cost Scores Ordination' (PICS-Ord). The method works via ordination of sequence identity or cost scores matrices by means of Principal Coordinates Analysis (PCoA). After identification of ambiguous regions, the method computes pairwise distances as sequence identities or cost scores, ordinates the resulting distance matrix by means of PCoA, and encodes the principal coordinates as ordered integers. Three biological and 100 simulated datasets were used to assess the performance of the new method. Results Including ambiguous regions coded by means of PICS-Ord increased topological accuracy, resolution, and bootstrap support in real biological and simulated datasets compared to the alternative of excluding such regions from the analysis a priori. In terms of accuracy, PICS-Ord performs equal to or better than previously available methods of ambiguous region coding (e.g., INAASE), with the advantage of a practically unlimited alignment size and increased analytical speed and the possibility of PICS-Ord scores to be analyzed together with DNA data in a partitioned maximum likelihood model. Conclusions Advantages of PICS-Ord over step matrix-based ambiguous region coding with INAASE include a practically unlimited number of OTUs and seamless integration of PICS-Ord codes into phylogenetic datasets, as well as the increased speed of phylogenetic analysis. Contrary to word- and frequency-based methods, PICS-Ord maintains the advantage of pairwise sequence alignment to derive distances, and the method is flexible with respect to the calculation of distance scores. In addition to distance and maximum parsimony, PICS-Ord codes can be analyzed in a Bayesian or maximum likelihood framework. RAxML (version 7.2.6 or higher that was developed for this study) allows up to 32-state ordered or unordered characters. A GTR, MK, or ORDERED model can be applied to analyse the PICS-Ord codes partition, with GTR performing slightly better than MK and ORDERED. Availability An implementation of the PICS-Ord algorithm is available from http://scit.us/projects/ngila/wiki/PICS-Ord. It requires both the statistical software, R http://www.r-project.org and the alignment software Ngila http://scit.us/projects/ngila. PMID:21214904

  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. Do Market Incentives Crowd Out Charitable Giving?

    PubMed

    Deck, Cary; Kimbrough, Erik O

    2013-12-01

    Donations and volunteerism can be conceived as market transactions with a zero explicit price. However, evidence suggests people may not view zero as just another price when it comes to pro-social behavior. Thus, while markets might be expected to increase the supply of assets available to those in need, some worry such financial incentives will crowd out altruistic giving. This paper reports laboratory experiments directly investigating the degree to which market incentives crowd out large, discrete charitable donations in a setting related to deceased organ donation. The results suggest markets increase the supply of assets available to those in need. However, as some critics fear, market incentives disproportionately influence the relatively poor. PMID:24348002

  15. Resolution of velocity ambiguities for MPRF frequency agile radars in multiple target environment

    NASA Astrophysics Data System (ADS)

    Albano, Gherardo; Cacopardi, Saverio; Fedele, Gennaro

    A Doppler correlation technique to extract target velocity data in MPRF (medium pulse repetition frequency) radars by starting from ambiguous measurements is presented. A two-step procedure that assures satisfactory performance for a multiple target environment and frequency agile radars is proposed. The performances have been assessed through a computer simulation which allowed the selection of the best values for Doppler coincidence threshold K and filter enlargement beta. In particular, the values K = L - 1 and beta = 30 percent represent the best tradeoff, since they give a probability of correct velocity resolution greater than 99.5 percent. It is shown that the velocity correlation algorithm can also operate as a deghosting filter.

  16. 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

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

    ERIC Educational Resources Information Center

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

    2007-01-01

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

  18. 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.

  19. 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.

  20. 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

  1. [Ambiguity in Eric Kandel's neuroscientific basis of psychiatry].

    PubMed

    Glas, G

    2006-01-01

    The philosophical principles underlying the work of Eric Kandel are investigated on the basis of his innovative paper entitled 'A new intellectual framework for psychiatry' (Kandel 1998). A careful analysis of the concepts involved reveals some ambiguity in Kandel's proposition in the mind-body debate. On the one hand Kandel uses formulations that are compatible with (classical) psychophysical identity theories; on the other hand he expresses views that actually have more in common with non-eliminative physicalism (or epiphenomenalism). In addition, he weakens his position by using misleading metaphors an analogies. This can lead to what is known as the 'mereological fallacy'. The final part of the article examines what this ambiguity tells us about Kandel's views on psychotherapy and the social justification for psychiatry. Kandel's approach can lead to a pointless narrowing down of the psychiatrist's normative role and to an over-restrictive attitude to psychotherapy. PMID:17151995

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

    SciTech Connect

    Bespalko, S.J.; Sindt, A.

    1997-10-01

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

  3. Decision making and ambiguity in auditory stream segregation

    PubMed Central

    Deike, Susann; Heil, Peter; Böckmann-Barthel, Martin; Brechmann, André

    2015-01-01

    Researchers of auditory stream segregation have largely taken a bottom-up view on the link between physical stimulus parameters and the perceptual organization of sequences of ABAB sounds. However, in the majority of studies, researchers have relied on the reported decisions of the subjects regarding which of the predefined percepts (e.g., one stream or two streams) predominated when subjects listened to more or less ambiguous streaming sequences. When searching for neural mechanisms of stream segregation, it should be kept in mind that such decision processes may contribute to brain activation, as also suggested by recent human imaging data. The present study proposes that the uncertainty of a subject in making a decision about the perceptual organization of ambiguous streaming sequences may be reflected in the time required to make an initial decision. To this end, subjects had to decide on their current percept while listening to ABAB auditory streaming sequences. Each sequence had a duration of 30 s and was composed of A and B harmonic tone complexes differing in fundamental frequency (ΔF). Sequences with seven different ΔF were tested. We found that the initial decision time varied non-monotonically with ΔF and that it was significantly correlated with the degree of perceptual ambiguity defined from the proportions of time the subjects reported a one-stream or a two-stream percept subsequent to the first decision. This strong relation of the proposed measures of decision uncertainty and perceptual ambiguity should be taken into account when searching for neural correlates of auditory stream segregation. PMID:26321899

  4. The "Give & Take" Formative Evaluation. Research Report 87.

    ERIC Educational Resources Information Center

    Agency for Instructional Television, Bloomington, IN.

    "Give & Take" is a series of 12 15-minute television/film programs and related print materials on consumer economics designed to improve the economic knowledge and decision-making skills of 13- to 15-year-old students. This report describes the processes and presents the results of"Give & Take" formative evaluations which were conducted in…

  5. Impaired semantic inhibition during lexical ambiguity repetition in Parkinson's disease.

    PubMed

    Copland, David A; Sefe, Gameli; Ashley, Jane; Hudson, Carrie; Chenery, Helen J

    2009-09-01

    Impairments of semantic processing and inhibition have been observed in Parkinson's disease (PD), however, the consequences of faulty meaning selection and suppression have not been considered in terms of subsequent lexical processing. The present study employed a lexical ambiguity repetition paradigm where the first presentation of an ambiguity paired with a target biasing its dominant or subordinate meaning (e.g., bank - money or bank - river) was followed after several intervening trials by a presentation of the same ambiguity paired with a different target that biases the same (congruent) or a different (incongruent) meaning to that biased on the first presentation. Meaning dominance (dominant or subordinate weaker meanings) and interstimulus interval (ISI) were manipulated. Analyses conducted on the second presentation indicated priming of congruent meanings and no priming for the incongruent meanings at both short and long ISIs in the healthy controls, consistent with suppression of meanings competing with the representation biased in the first presentation. In contrast, the PD group failed to dampen activation for the incongruent meaning at the long ISI when the first presentation was subordinate. This pattern is consistent with an impairment of meaning suppression which is observed under controlled processing conditions and varies as a function of meaning dominance of the first presentation. These findings further refine our understanding of lexical-semantic impairments in PD and suggest a mechanism that may contribute to discourse comprehension impairments in this population. PMID:19393992

  6. Another Kind of Ambiguous Loss: Seventh-Day Adventist Women in Mixed-Orientation Marriages

    ERIC Educational Resources Information Center

    Hernandez, Barbara C.; Wilson, Colwick M.

    2007-01-01

    Narratives of five Seventh-day Adventist heterosexual women whose mixed-orientation marriages ended were analyzed through the lens of ambiguous loss. Thematic coding identified a wave-like process of changing emotional foci that emerged from their experience during marital dissolution. Elements of ambiguous loss included boundary ambiguity,…

  7. 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

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

    SciTech Connect

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

    2014-01-10

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

  9. 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…

  10. 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

  11. 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)

  12. Giving That Doesn't Hurt

    ERIC Educational Resources Information Center

    Dunseth, William B.

    1978-01-01

    The annuity and trust income program (deferred giving) permits donors to give more than they thought they could. Suggestions for establishing and monitoring such programs are offered in this article, which is a condensation of remarks at the National Conference on Trusteeship. (Author/LBH)

  13. Elimination of the direction ambiguity and the dead zone in spectrally resolved interferometry

    NASA Astrophysics Data System (ADS)

    Yun, Young Ho; Seo, Yong Bum; Joo, Ki-Nam

    2016-03-01

    We propose a very simple and effective technique to eliminate the direction ambiguity and the dead zone, which limit the measurable range in spectrally resolved interferometry (SRI). By using a dispersive material, the nonlinear spectral phase caused by the dispersion can provide useful information and determine the direction of measuring distances. In addition, the dead zone is removed by two complementary measurement results in dichroic SRI. As the results of feasibility experiments, it was confirmed that the nonlinearity of the spectral phase successfully determined the direction of the measuring distances. Moreover, the final linear distances in the whole measurement range without the dead zone was obtained in dichroic SRI with two LEDs.

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

    SciTech Connect

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

    2014-04-15

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

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

    PubMed

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

    2012-06-01

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

  16. Know Concentration Before Giving Acetaminophen to Infants

    MedlinePlus

    ... For Consumers Consumer Updates Know Concentration Before Giving Acetaminophen to Infants Share Tweet Linkedin Pin it More ... Consumer Updates RSS Feed Download PDF (221 K) Acetaminophen Safety (Podcast) On this page Overdosing Has Been ...

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

    PubMed Central

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

    2015-01-01

    Avoidance behavior is a critical component of many psychiatric disorders, and as such, it is important to understand how avoidance behavior arises, and whether it can be modified. In this study, we used empirical and computational methods to assess the role of informational feedback and ambiguous outcome in avoidance behavior. We adapted a computer-based probabilistic classification learning task, which includes positive, negative and no-feedback outcomes; the latter outcome is ambiguous as it might signal either a successful outcome (missed punishment) or a failure (missed reward). Prior work with this task suggested that most healthy subjects viewed the no-feedback outcome as strongly positive. Interestingly, in a later version of the classification task, when healthy subjects were allowed to opt out of (i.e. avoid) responding, some subjects (“avoiders”) reliably avoided trials where there was a risk of punishment, but other subjects (“non-avoiders”) never made any avoidance responses at all. One possible interpretation is that the “non-avoiders” valued the no-feedback outcome so positively on punishment-based trials that they had little incentive to avoid. Another possible interpretation is that the outcome of an avoided trial is unspecified and that lack of information is aversive, decreasing subjects’ tendency to avoid. To examine these ideas, we here tested healthy young adults on versions of the task where avoidance responses either did or did not generate informational feedback about the optimal response. Results showed that provision of informational feedback decreased avoidance responses and also decreased categorization performance, without significantly affecting the percentage of subjects classified as “avoiders.” To better understand these results, we used a modified Q-learning model to fit individual subject data. Simulation results suggest that subjects in the feedback condition adjusted their behavior faster following better-than-expected outcomes, compared to subjects in the no-feedback condition. Additionally, in both task conditions, “avoiders” adjusted their behavior faster following worse-than-expected outcomes, and treated the ambiguous no-feedback outcome as less rewarding, compared to non-avoiders. Together, results shed light on the important role of ambiguous and informative feedback in avoidance behavior. PMID:26630279

  18. Lament: giving words to nurses' grief.

    PubMed

    Lick, Renee C

    2012-01-01

    Nurses are intimately present with people who are seriously ill, suffering and dying--giving rise to the need to cry out and give words to personal pain and grief. Practicing a regular rhythm of lament to God as found in the psalms of the Bible can assist nurses in coping with grief and prepare them to continue to care for the hurting with God's strength and hope. PMID:22866376

  19. 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

  20. 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.

  1. Resolution of front-back ambiguity in spatial hearing by listener and source movement.

    PubMed

    Wightman, F L; Kistler, D J

    1999-05-01

    Normally, the apparent position of a sound source corresponds closely to its actual position. However, in some experimental situations listeners make large errors, such as indicating that a source in the frontal hemifield appears to be in the rear hemifield, or vice versa. These front-back confusions are thought to be a result of the inherent ambiguity of the primary interaural difference cues, interaural time difference (ITD) in particular. A given ITD could have been produced by a sound source anywhere on the so-called "cone of confusion." More than 50 years ago Wallach [J. Exp. Psychol. 27, 339-368 (1940)] argued that small head movements could provide the information necessary to resolve the ambiguity. The direction of the change in ITD that accompanies a head rotation is an unambiguous indicator of the proper hemifield. The experiments reported here are a modern test of Wallach's hypothesis. Listeners indicated the apparent positions of real and virtual sound sources in conditions in which head movements were either restricted or encouraged. The front-back confusions made in the restricted condition nearly disappeared in the condition in which head movements were encouraged. In a second experiment head movements were restricted, but the sound source was moved, either by the experimenter or by the listener. Only when the listener moved the sound source did front-back confusions disappear. The results clearly support Wallach's hypothesis and suggest further that head movements are not required to produce the dynamic cues needed to resolve front-back ambiguity. PMID:10335634

  2. 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

  3. Dressed skeleton expansion and the coupling scale ambiguity problem

    SciTech Connect

    Lu, Hung Jung

    1992-09-01

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

  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. Sounding of the Ion Energization Region: Resolving Ambiguities

    NASA Technical Reports Server (NTRS)

    LaBelle, James

    2003-01-01

    Dartmouth College provided a single-channel high-frequency wave receiver to the Sounding of the Ion Energization Region: Resolving Ambiguities (SIERRA) rocket experiment launched from Poker Flat, Alaska, in January 2002. The receiver used signals from booms, probes, preamplifiers, and differential amplifiers provided by Cornell University coinvestigators. Output was to a dedicated 5 MHz telemetry link provided by WFF, with a small amount of additional Pulse Code Modulation (PCM) telemetry required for the receiver gain information. We also performed preliminary analysis of the data. The work completed is outlined below, in chronological order.

  7. Particle filter-based estimation of inter-frequency phase bias for real-time GLONASS integer ambiguity resolution

    NASA Astrophysics Data System (ADS)

    Tian, Yumiao; Ge, Maorong; Neitzel, Frank

    2015-11-01

    GLONASS could hardly reach the positioning performance of GPS, especially for fast and real-time precise positioning. One of the reasons is the phase inter-frequency bias (IFB) at the receiver end prevents its integer ambiguity resolution. A number of studies were carried out to achieve the integer ambiguity resolution for GLONASS. Based on some of the revealed IFB characteristics, for instance IFB is a linear function of the received carrier frequency and L1 and L2 have the same IFB in unit of length, most of recent methods recommend estimating the IFB rate together with ambiguities. However, since the two sets of parameters are highly correlated, as demonstrated in previous studies, observations over several hours up to 1 day are needed even with simultaneous GPS observations to obtain a reasonable solution. Obviously, these approaches cannot be applied for real-time positioning. Actually, it can be demonstrated that GLONASS ambiguity resolution should also be available even for a single epoch if the IFB rate is precisely known. In addition, the closer the IFB rate value is to its true value, the larger the fixing RATIO will be. Based on this fact, in this paper, a new approach is developed to estimate the IFB rate by means of particle filtering with the likelihood function derived from RATIO. This approach is evaluated with several sets of experimental data. For both static and kinematic cases, the results show that IFB rates could be estimated precisely just with GLONASS data of a few epochs depending on the baseline length. The time cost with a normal PC can be controlled around 1 s and can be further reduced. With the estimated IFB rate, integer ambiguity resolution is available immediately and as a consequence, the positioning accuracy is improved significantly to the level of GPS fixed solution. Thus the new approach enables real-time precise applications of GLONASS.

  8. Partial Ambiguity Resolution for Ground and Space-Based Applications in a GPS+Galileo scenario: A simulation study

    NASA Astrophysics Data System (ADS)

    Nardo, A.; Li, B.; Teunissen, P. J. G.

    2016-01-01

    Integer Ambiguity Resolution (IAR) is the key to fast and precise GNSS positioning. The proper diagnostic metric for successful IAR is provided by the ambiguity success rate being the probability of correct integer estimation. In this contribution we analyse the performance of different GPS+Galileo models in terms of number of epochs needed to reach a pre-determined success rate, for various ground and space-based applications. The simulation-based controlled model environment enables us to gain insight into the factors contributing to the ambiguity resolution strength of the different GPS+Galileo models. Different scenarios of modernized GPS+Galileo are studied, encompassing the long baseline ground case as well as the medium dynamics case (airplane) and the space-based Low Earth Orbiter (LEO) case. In our analyses of these models the capabilities of partial ambiguity resolution (PAR) are demonstrated and compared to the limitations of full ambiguity resolution (FAR). The results show that PAR is generally a more efficient way than FAR to reduce the time needed to achieve centimetre-level positioning precision. For long single baselines, PAR can achieve time reductions of fifty percent to achieve such precision levels, while for multiple baselines it even becomes more effective, reaching reductions up to eighty percent for four station networks. For a LEO, the rapidly changing observation geometry does not even allow FAR, while PAR is then still possible for both dual- and triple-frequency scenarios. With the triple-frequency GPS+Galileo model the availability of precise positioning improves by fifteen percent with respect to the dual-frequency scenario.

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

    PubMed Central

    Yiltiz, Hörmetjan; Chen, Lihan

    2015-01-01

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

  10. Resolving The Kinematic Distance Ambiguity Towards 6.7 Ghz Methanol Masers

    NASA Astrophysics Data System (ADS)

    Pandian, Jagadheep D.; Momjian, E.; Goldsmith, P.

    2006-09-01

    We present preliminary results on VLA observations carried out to determine distances to 6.7 GHz methanol masers by studying the HI absorption towards continuum sources associated with them. Methanol masers are excellent tracers of early stages of high-mass star formation, and are hence expected to trace the spiral density waves of the Galaxy. Since young massive star forming regions are heavily obscured even in near infrared wavelengths, distances to methanol masers are primarily kinematic in nature. Unfortunately, a significant fraction of sources in the first quadrant suffer from the distance ambiguity which needs to be resolved before inferences regarding Galactic structure and methanol maser luminosities can be drawn. One of the techniques that has been used successfully to resolve the kinematic distance ambiguity, especially towards ultracompact HII regions, is to measure an HI absorption spectrum towards the source of interest. Since 6.7 GHz methanol masers are associated with a very early stage of massive star formation, they frequently do not have any associated radio continuum. However, many methanol masers have nearby compact radio sources as seen in NVSS, which might be more evolved massive stars in the same cluster as the maser itself. These sources were observed with the GBT in C-Band to search for recombination lines to verify the thermal nature of the radio continuum emission and the association of the methanol maser with the radio source. Sixty methanol masers were observed with the VLA to resolve the kinematic distance ambiguity using the HI absorption spectra. The low declination sources were observed in the CnB configuration, while other sources were observed in the C configuration. This research is funded by the NAIC which is operated by Cornell University under a cooperative agreement with the NSF. The NRAO is a facility of the NSF operated under cooperative agreement by AUI.

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

    PubMed Central

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

    2015-01-01

    The ability to perceive discrete sound streams in the presence of competing sound sources relies on multiple mechanisms that organize the mixture of the auditory input entering the ears. Many studies have focused on mechanisms that contribute to integrating sounds that belong together into one perceptual stream (integration) and segregating those that come from different sound sources (segregation). However, little is known about mechanisms that allow us to perceive individual sound sources within a dynamically changing auditory scene, when the input may be ambiguous, and heard as either integrated or segregated. This study tested the question of whether focusing on one of two possible sound organizations suppressed representation of the alternative organization. We presented listeners with ambiguous input and cued them to switch between tasks that used either the integrated or the segregated percept. Electrophysiological measures indicated which organization was currently maintained in memory. If mutual exclusivity at the neural level was the rule, attention to one of two possible organizations would preclude neural representation of the other. However, significant MMNs were elicited to both the target organization and the unattended, alternative organization, along with the target-related P3b component elicited only to the designated target organization. Results thus indicate that both organizations (integrated and segregated) were simultaneously maintained in memory regardless of which task was performed. Focusing attention to one aspect of the sounds did not abolish the alternative, unattended organization when the stimulus input was ambiguous. In noisy environments, such as walking on a city street, rapid and flexible adaptive processes are needed to help facilitate rapid switching to different sound sources in the environment. Having multiple representations available to the attentive system would allow for such flexibility, needed in everyday situations to maintain stable auditory percepts, and to allow rapid scanning of interesting events in a busy environment. PMID:25281308

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

    NASA Astrophysics Data System (ADS)

    Henkel, Patrick

    2015-04-01

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

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

    PubMed

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

    2014-09-30

    The ability to perceive discrete sound streams in the presence of competing sound sources relies on multiple mechanisms that organize the mixture of the auditory input entering the ears. Many studies have focused on mechanisms that contribute to integrating sounds that belong together into one perceptual stream (integration) and segregating those that come from different sound sources (segregation). However, little is known about mechanisms that allow us to perceive individual sound sources within a dynamically changing auditory scene, when the input may be ambiguous, and heard as either integrated or segregated. This study tested the question of whether focusing on one of two possible sound organizations suppressed representation of the alternative organization. We presented listeners with ambiguous input and cued them to switch between tasks that used either the integrated or the segregated percept. Electrophysiological measures indicated which organization was currently maintained in memory. If mutual exclusivity at the neural level was the rule, attention to one of two possible organizations would preclude neural representation of the other. However, significant MMNs were elicited to both the target organization and the unattended, alternative organization, along with the target-related P3b component elicited only to the designated target organization. Results thus indicate that both organizations (integrated and segregated) were simultaneously maintained in memory regardless of which task was performed. Focusing attention to one aspect of the sounds did not abolish the alternative, unattended organization when the stimulus input was ambiguous. In noisy environments, such as walking on a city street, rapid and flexible adaptive processes are needed to help facilitate rapid switching to different sound sources in the environment. Having multiple representations available to the attentive system would allow for such flexibility, needed in everyday situations to maintain stable auditory percepts, and to allow rapid scanning of interesting events in a busy environment. PMID:25281308

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

    ERIC Educational Resources Information Center

    Yoruk, Baris K.

    2012-01-01

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

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

    ERIC Educational Resources Information Center

    Yoruk, Baris K.

    2012-01-01

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

  16. 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.

  17. Perceived Ambiguity About Cancer Prevention Recommendations: Relationship to Perceptions of Cancer Preventability, Risk, and Worry

    PubMed Central

    Han, Paul K. J.; Moser, Richard P.; Klein, William M. P.

    2014-01-01

    In this study, we apply the concept of “ambiguity,” as developed in the decision theory literature, to an analysis of potential psychological consequences of uncertainty about cancer prevention recommendations. We used Health Information National Trends Survey (HINTS) 2003 data to examine how perceived ambiguity about cancer prevention recommendations relates to three other cognitive variables known to influence cancer-protective behavior: perceived cancer preventability, perceived cancer risk, and cancer-related worry. Using logistic regression analyses, we tested several predictions derived from a review of literature on the effects of ambiguity perceptions on decision making, cognitions, and emotions. We found perceived ambiguity to have a strong negative relationship with perceived cancer preventability, consistent with “ambiguity aversion”—a pessimistic bias in the interpretation of ambiguity. Cancer worry moderated this relationship; ambiguity aversion increased with higher levels of worry. At the same time, perceived ambiguity was positively related to both perceived cancer risk and cancer worry. Furthermore, perceived risk partially mediated the relationship between perceived ambiguity and worry. These findings suggest that perceived ambiguity about cancer prevention recommendations may have broad and important effects on other health cognitions. We discuss ethical implications of these findings for health communication efforts, and propose a tentative causal model to guide future research. PMID:16641074

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

    NASA Astrophysics Data System (ADS)

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

    2014-07-01

    A synodic period of an asteroid can be derived from its lightcurve by standard methods like Fourier-series fitting. A problem appears when results of observations are based on less than a full coverage of a lightcurve and/or high level of noise. Also, long gaps between individual lightcurves create an ambiguity in the cycle count which leads to aliases. Excluding binary systems and objects with non-principal-axis rotation, the rotation period is usually identical to the period of the second Fourier harmonic of the lightcurve. There are cases, however, where it may be connected with the 1st, 3rd, or 4th harmonic and it is difficult to choose among them when searching for the period. To help remove such uncertainties we analysed asteroid lightcurves for a range of shapes and observing/illuminating geometries. We simulated them using a modified internal code from the ISAM service (Marciniak et al. 2012, A&A 545, A131). In our computations, shapes of asteroids were modeled as Gaussian random spheres (Muinonen 1998, A&A, 332, 1087). A combination of Lommel-Seeliger and Lambert scattering laws was assumed. For each of the 100 shapes, we randomly selected 1000 positions of the spin axis, systematically changing the solar phase angle with a step of 5°. For each lightcurve, we determined its peak-to-peak amplitude, fitted the 6th-order Fourier series and derived the amplitudes of its harmonics. Instead of the number of the lightcurve extrema, which in many cases is subjective, we characterized each lightcurve by the order of the highest-amplitude Fourier harmonic. The goal of our simulations was to derive statistically significant conclusions (based on the underlying assumptions) about the dominance of different harmonics in the lightcurves of the specified amplitude and phase angle. The results, presented in the Figure, can be used in individual cases to estimate the probability that the obtained lightcurve is dominated by a specified Fourier harmonic. Some of the conclusions are: (1) the 4th harmonic dominates about 1 percent of lightcurves only at low amplitudes (A<0.1 mag, α < 40°). (2) The dominance of the 3rd harmonic can be observed more often only in the case of near-Earth asteroids, observed at α > 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 α≃ 40°, A<0.9~mag for α ≃ 50°). (4) In 100 percent of the cases, the 2nd harmonic dominates the lightcurves of MBAs whose amplitudes A > 0.2 mag.

  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 people’s level of commitment to healthism/risk culture and on their level of confidence in the health authorities and mainstream medicine. PMID:25789201

  20. 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

  1. 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.

  2. Non-Abelian gauge redundancy and entropic ambiguities

    NASA Astrophysics Data System (ADS)

    Balachandran, A. P.; de Queiroz, A. R.; Vaidya, S.

    2015-04-01

    The von Neumann entropy of a generic quantum state is not unique unless the state can be uniquely decomposed as a sum of extremal or pure states. Therefore one reaches the remarkable possibility that there may be many entropies for a given state. We show that this happens if the GNS representation (of the algebra of observables in some quantum state) is reducible, and some representations in the decomposition occur with non-trivial degeneracy. This ambiguity in entropy, which can occur at zero temperature, can often be traced to a gauge symmetry emergent from the non-trivial topological character of the configuration space of the underlying system. We also establish the analogue of an H-theorem for this entropy by showing that its evolution is Markovian, determined by a stochastic matrix. After demonstrating this entropy ambiguity for the simple example of the algebra of 2 × 2 matrices, we argue that the degeneracies in the GNS representation can be interpreted as an emergent broken gauge symmetry, and play an important role in the analysis of emergent entropy due to non-Abelian anomalies. We work out the simplest situation with such non-Abelian symmetry, that of an ethylene molecule.

  3. Speech rhythm facilitates syntactic ambiguity resolution: ERP evidence.

    PubMed

    Roncaglia-Denissen, Maria Paula; Schmidt-Kassow, Maren; Kotz, Sonja A

    2013-01-01

    In the current event-related potential (ERP) study, we investigated how speech rhythm impacts speech segmentation and facilitates the resolution of syntactic ambiguities in auditory sentence processing. Participants listened to syntactically ambiguous German subject- and object-first sentences that were spoken with either regular or irregular speech rhythm. Rhythmicity was established by a constant metric pattern of three unstressed syllables between two stressed ones that created rhythmic groups of constant size. Accuracy rates in a comprehension task revealed that participants understood rhythmically regular sentences better than rhythmically irregular ones. Furthermore, the mean amplitude of the P600 component was reduced in response to object-first sentences only when embedded in rhythmically regular but not rhythmically irregular context. This P600 reduction indicates facilitated processing of sentence structure possibly due to a decrease in processing costs for the less-preferred structure (object-first). Our data suggest an early and continuous use of rhythm by the syntactic parser and support language processing models assuming an interactive and incremental use of linguistic information during language processing. PMID:23409109

  4. Phase-wrapping ambiguity in along-track interferometry

    NASA Astrophysics Data System (ADS)

    Deming, Ross; Ilin, Roman; Best, Matthew

    2013-05-01

    In a previous SPIE paper we described several variations of along-track interferometry (ATI), which can be used for moving target detection and geo-location in clutter. ATI produces a phase map in range/Doppler coordinates by combining radar data from several receive channels separated fore-and-aft (along-track) on the sensor platform. In principle, the radial velocity of a moving target can be estimated from the ATI phase of the pixels in the target signature footprint. Once the radial velocity is known, the target azimuth follows directly. Unfortunately, the ATI phase is wrapped, i.e., it repeats in the interval [-?, ?], and therefore the mapping from ATI phase to target azimuth is non-unique. In fact, depending on the radar system parameters, each detected target can map to several equally-likely azimuth values. In the present paper we discuss a signal processing method for resolving the phase wrapping ambiguity, in which the radar bandwidth is split into a high and low sub-band in software, and an ATI phase map is generated for each. By subtracting these two phase maps we can generate a coarse, but unambiguous, radial velocity estimate. This coarse estimate is then combined with the fine, but ambiguous estimate to pinpoint the target radial velocity, and therefore its azimuth. Since the coarse estimate is quite sensitive to noise, a rudimentary tracker is used to help smooth out the phase errors. The method is demonstrated on Gotcha 2006 Challenge data.

  5. 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

  6. 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.

  7. Conscientious refusals and reason-giving.

    PubMed

    Marsh, Jason

    2014-07-01

    Some philosophers have argued for what I call the reason-giving requirement for conscientious refusal in reproductive healthcare. According to this requirement, healthcare practitioners who conscientiously object to administering standard forms of treatment must have arguments to back up their conscience, arguments that are purely public in character. I argue that such a requirement, though attractive in some ways, faces an overlooked epistemic problem: it is either too easy or too difficult to satisfy in standard cases. I close by briefly considering whether a version of the reason-giving requirement can be salvaged despite this important difficulty. PMID:23445457

  8. Shared Gaussian Process Latent Variable Models for Handling Ambiguous Facial Expressions

    NASA Astrophysics Data System (ADS)

    Ek, Carl Henrik; Jaeckel, Peter; Campbell, Neill; Lawrence, Neil D.; Melhuish, Chris

    2009-03-01

    Despite the fact, that, in reality facial expressions occur as a result of muscle actions, facial expression models assume an inverse functional relationship, which makes muscles action be the result of facial expressions. Clearly, facial expression should be expressed as a function of muscle action, the other way around as previously suggested. Furthermore, a human facial expression space and the robots actuator space have common features. However, there are also features that the one or the other does not have. This suggests modelling shared and non-shared feature variance separately. To this end we propose Shared Gaussian Process Latent Variable Models (Shared GP-LVM) for models of facial expressions, which assume shared and private features between an input and output space. In this work, we are focusing on the detection of ambiguities within data sets of facial behaviour. We suggest ways of modelling and mapping of facial motion from a representation of human facial expressions to a robot's actuator space. We aim to compensate for ambiguities caused by interference of global with local head motion and the constrained nature of Active Appearance Models, used for tracking.

  9. Profiles of Effective Corporate Giving Programs.

    ERIC Educational Resources Information Center

    Knauft, E. B.

    A research study of 48 United States corporate giving programs is described. The companies are generally large or mid-range in size and represent 15 different business and industry classifications. The size of their contributions programs ranged from $98,000 to $53 million in annual grants, with a median of $4.3 million. About three-fourths of the…

  10. Community College Alumni: Predicting Who Gives

    ERIC Educational Resources Information Center

    Skari, Lisa Ann

    2014-01-01

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

  11. Asian American Giving to US Higher Education

    ERIC Educational Resources Information Center

    Tsunoda, Kozue

    2010-01-01

    Asian Americans have had significant impacts on and within mainstream US society, and their great efforts and gifts in the name of charitable causes are no exception. This study aims to examine perceptions within American university development offices about Asian American giving to US higher education. The article begins with a literature review…

  12. Todd Baumann Gives a Thumbs Up

    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 ...

  13. A Season of Giving. Learning with Literature.

    ERIC Educational Resources Information Center

    Freeman, Judy

    1992-01-01

    Reviews elementary school books that help steer children away from the commercial aspects of gift giving and receiving during the holiday season and focus on the gifts of caring, generosity, selflessness, friendship, and tolerance. Teaching tips, class discussions, and literary tie-ins are included. (SM)

  14. How School Boards Give Recognition to Staff.

    ERIC Educational Resources Information Center

    Canadian Education Association, Toronto (Ontario).

    This report focuses on measures that can be taken by school boards to give recognition to their staff and improve the quality of their employees' working life. The report is based on the findings of a survey done by the Canadian Education Association, to which 103 out of 224 school boards responded. The first section describes ways of recognizing

  15. Leadership Giving: Key to a Successful Fund.

    ERIC Educational Resources Information Center

    Whittier, H. Sargent, Jr.

    1980-01-01

    The success of the annual fund-raising campaign is seen to depend in large part on a careful search for and cultivation of a select group of generous donors. Leadership giving is defined, and creating gift clubs, solicitation, competition and challenges, pitfalls, and renewal are discussed. (Author/MLW)

  16. Giving the 'Green Light' to Migraine Relief

    MedlinePlus

    ... medlineplus/news/fullstory_158888.html Giving the 'Green Light' to Migraine Relief Experimental light therapy finds it can ease sensitivity, pain for ... 17, 2016 (HealthDay News) -- A new study sheds light -- literally -- on a potential means of easing migraine ...

  17. Community College Alumni: Predicting Who Gives

    ERIC Educational Resources Information Center

    Skari, Lisa Ann

    2014-01-01

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

  18. The Costs and Benefits of Deferred Giving.

    ERIC Educational Resources Information Center

    Fink, Norman S.; Metzler, Howard C.

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

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

    PubMed Central

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

    2015-01-01

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

  20. 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.

  1. 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.

  2. 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

  3. Effects of contextual information and stimulus ambiguity on overt visual sampling behavior.

    PubMed

    Kietzmann, T C; König, P

    2015-05-01

    The sampling of our visual environment through saccadic eye movements is an essential function of the brain, allowing us to overcome the limits of peripheral vision. Understanding which parts of a scene attract overt visual attention is subject to intense research, and considerable progress has been made in unraveling the underlying cortical mechanisms. In contrast to spatial aspects, however, relatively little is understood about temporal aspects of overt visual sampling. At every fixation, the oculomotor system faces the decision whether to keep exploring different aspects of an object or scene or whether to remain fixated to allow for in-depth cortical processing - a situation that can be understood in terms of an exploration-exploitation dilemma. To improve our understanding of the factors involved in these decisions, we here investigate how the level of visual information, experimentally manipulated by scene context and stimulus ambiguity, changes the sampling behavior preceding the recognition of centrally presented ambiguous and disambiguated objects. Behaviorally, we find that context, although only presented until the first voluntary saccade, biases the perceptual outcome and significantly reduces reaction times. Importantly, we find that increased information about an object significantly alters its visual exploration, as evident through increased fixation durations and reduced saccade amplitudes. These results demonstrate that the initial sampling of an object, preceding its recognition, is subject to change based on the amount of information available in the system: increased evidence for its identity biases the exploration-exploitation strategy towards in-depth analyses. PMID:25805148

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

    PubMed Central

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

    2015-01-01

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

  5. Virtual baseline method for Beidou attitude determination - An improved long-short baseline ambiguity resolution method

    NASA Astrophysics Data System (ADS)

    Lu, Liangqing; Li, Yong; Rizos, Chris

    2013-03-01

    Ambiguity resolution (AR) is a critical step for successful attitude determination using carrier phase measurements of a satellite navigation system such as Beidou. This paper proposes an improved method for AR in support of Beidou attitude determination based on the concept of a "virtual baseline". In the traditional long-short baseline method, the short baseline is limited to a length less than half of the carrier wave length of the Beidou signals. In the proposed method, a virtual short baseline is formed by differencing two collinear baselines. The AR equations for virtual short and long baselines are derived and the factors impacting the AR accuracy are analysed. Numerical simulation studies were carried out to evaluate the performance of the proposed AR method. The simulation results confirmed that the proposed method is an improvement over the traditional approach -- not only is it easier to deploy collinear antennas but also it keeps the capability of epoch-by-epoch AR, which makes it immune to cycle slips and there is no need for initialisation of ambiguity searching.

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

    PubMed Central

    Waite, Polly; Codd, Jon; Creswell, Cathy

    2015-01-01

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

  7. Ambiguities and symmetry relations associated with fermionic tensor densities

    SciTech Connect

    Dallabona, G.; Battistel, O. A.

    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.

  8. Resolving ambiguities in nanowire field-effect transistor characterization

    NASA Astrophysics Data System (ADS)

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

    2015-10-01

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

  9. 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.

  10. Dynamical ambiguities in models with spontaneous Lorentz violation

    NASA Astrophysics Data System (ADS)

    Bonder, Yuri; Escobar, Carlos A.

    2016-01-01

    Spontaneous Lorentz violation is a viable mechanism to look for Planck scale physics. In this work, we study spontaneous Lorentz violation models, in flat spacetime, where a vector field produces such a violation and matter is modeled by a complex scalar field. We show that it is possible to construct a Hamilton density for which the evolution respects the dynamical constraints. However, we also find that the initial data, as required by standard field theory, does not determine the fields evolution in a unique way. In addition, we present some examples where the physical effects of such ambiguities can be recognized. As a consequence, the proposals in which the electromagnetic and gravitational interactions emerge from spontaneous Lorentz violation are challenged.

  11. Caveolin-1: an ambiguous partner in cell signalling and cancer

    PubMed Central

    Quest, Andrew F G; Gutierrez-Pajares, Jorge L; Torres, Vicente A

    2008-01-01

    Caveolae are small plasma membrane invaginations that have been implicated in a variety of functions including transcytosis, potocytosis and cholesterol transport and signal transduction. The major protein component of this compartment is a family of proteins called caveolins. Experimental data obtained in knockout mice have provided unequivocal evidence for a requirement of caveolins to generate morphologically detectable caveolae structures. However, expression of caveolins is not sufficient per seto assure the presence of these structures. With respect to other roles attributed to caveolins in the regulation of cellular function, insights are even less clear. Here we will consider, more specifically, the data concerning the ambiguous roles ascribed to caveolin-1 in signal transduction and cancer. In particular, evidence indicating that caveolin-1 function is cell context dependent will be discussed. PMID:18400052

  12. 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

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

    PubMed

    Gandolfi, Laura

    2010-01-01

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

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

    PubMed Central

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

    2015-01-01

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

  15. Space-time ambiguity functions for electronically scanned ISR applications

    NASA Astrophysics Data System (ADS)

    Swoboda, John; Semeter, Joshua; Erickson, Philip

    2015-05-01

    Electronically steerable array (ESA) technology has recently been applied to incoherent scatter radar (ISR) systems. These arrays allow for pulse-to-pulse steering of the antenna beam to collect data in a three-dimensional region. This is in direct contrast to dish-based antennas, where ISR acquisition is limited at any one time to observations in a two-dimensional slice. This new paradigm allows for more flexibility in the measurement of ionospheric plasma parameters. Multiple ESA-based ISR systems operate currently in the high-latitude region where the ionosphere is highly variable in both space and time. Because of the highly dynamic nature of the ionosphere in this region, it is important to differentiate between measurement-induced artifacts and the true behavior of the plasma. Often, three-dimensional ISR data produced by ESA systems are fitted in a spherical coordinate space and then the parameters are interpolated to a Cartesian grid, potentially introducing error and impacting the reconstructions of the plasma parameters. To take advantage of the new flexibility inherent in ESA systems, we present a new way of analyzing ISR observations through use of the space-time ambiguity function. The use of this new measurement ambiguity function allows us to pose the ISR observational problem in terms of a linear inverse problem whose goal is the estimate of the time domain lags of the intrinsic plasma autocorrelation function used for parameter fitting. The framework allows us to explore the impact of nonuniformity in plasma parameters in both time and space. We discuss examples of possible artifacts in high-latitude situations and discuss possible ways of reducing them and improving the quality of data products from electronically steerable ISRs.

  16. The Fungus Candida albicans Tolerates Ambiguity at Multiple Codons

    PubMed Central

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

    2016-01-01

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

  17. 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

    2015-05-01

    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-Wübbena 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 . 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.

  18. Intolerance of Uncertainty Is Associated With Increased Threat Appraisal and Negative Affect Under Ambiguity but Not Uncertainty.

    PubMed

    Chen, Jessamine Tsan-Hsiang; Lovibond, Peter F

    2016-01-01

    Intolerance of Uncertainty (IU) has gained increasing interest as a vulnerability factor for worry in Generalized Anxiety Disorder and other emotional disorders. We extended the procedure of Grupe and Nitschke (2011) to compare threat processing in High IU (n=29) and Low IU (n=26) participants. Participants viewed four cues: two reference cues that preceded aversive pictures on 100% or 0% of trials, and a target cue that preceded aversive pictures on 50% of trials (Uncertain condition). Participants were instructed about these probabilities in advance. In addition, we surprised participants with a second target cue that also preceded aversive pictures on 50% of trials but that had not been mentioned in the instructions (Ambiguous condition). Results provided preliminary evidence that High IU participants showed greater online threat expectancy, postexperimental covariation estimates and negative mood for the target cues compared to the reference cues. The results also suggest that among high IU individuals, ambiguity, rather than uncertainty per se, may be a particularly powerful trigger for biased threat appraisal and negative affect. Clinically, the results suggest that patients with high IU may benefit from interventions to help them calibrate the degree of risk in situations involving ambiguous threat. PMID:26763496

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

    PubMed Central

    Bethell, Emily J.; Koyama, Nicola F.

    2015-01-01

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

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

    PubMed

    Hahn, Noemi; Snedeker, Jesse; Rabagliati, Hugh

    2015-12-01

    Individuals with autism spectrum disorders (ASD) have often been reported to have difficulty integrating information into its broader context, which has motivated the Weak Central Coherence theory of ASD. In the linguistic domain, evidence for this difficulty comes from reports of impaired use of linguistic context to resolve ambiguous words. However, recent work has suggested that impaired use of linguistic context may not be characteristic of ASD, and is instead better explained by co-occurring language impairments. Here, we provide a strong test of these claims, using the visual world eye tracking paradigm to examine the online mechanisms by which children with autism resolve linguistic ambiguity. To address concerns about both language impairments and compensatory strategies, we used a sample whose verbal skills were strong and whose average age (7; 6) was lower than previous work on lexical ambiguity resolution in ASD. Participants (40 with autism and 40 controls) heard sentences with ambiguous words in contexts that either strongly supported one reading or were consistent with both (John fed/saw the bat). We measured activation of the unintended meaning through implicit semantic priming of an associate (looks to a depicted baseball glove). Contrary to the predictions of weak central coherence, children with ASD, like controls, quickly used context to resolve ambiguity, selecting appropriate meanings within a second. We discuss how these results constrain the generality of weak central coherence. Autism Res 2015, 8: 717-726. © 2015 International Society for Autism Research, Wiley Periodicals, Inc. PMID:25820816

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

    PubMed

    Bethell, Emily J; Koyama, Nicola F

    2015-07-01

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

  2. When to Cry Over Spilled Milk: Young Children’s Use of Category Information to Guide Inferences About Ambiguous Behavior

    PubMed Central

    Giles, Jessica W.; Heyman, Gail D.

    2010-01-01

    Three studies (N = 171) examined preschool children’s tendency to use category information to make inferences about ambiguous behavior. Children heard stories in which category information about story characters was manipulated and behavioral information was held constant. Participants were asked to evaluate, explain, and determine the significance of the behavior in question. Children tended to be harsher judges of the same ambiguous behaviors when performed by (a) humans as compared to animals, (b) boys compared to girls, and (c) older children compared to younger children. Results suggest that young children hold differentiated notions of the mental states and dispositions that underlie behavior and that these notions vary as a function of category membership. These findings support the conclusion that even young children can hold and use multiple folk psychologies. PMID:20953252

  3. Advice on Giving a Scientific Talk

    NASA Astrophysics Data System (ADS)

    Kurtz, D. W.

    2006-04-01

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

  4. 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.

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

    SciTech Connect

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

    2015-02-01

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

  6. 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.

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

    ERIC Educational Resources Information Center

    Logacev, Pavel; Vasishth, Shravan

    2016-01-01

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

  8. 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…

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

    ERIC Educational Resources Information Center

    Allen, Melissa L.; Chambers, Alison

    2011-01-01

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

  10. 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

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

    ERIC Educational Resources Information Center

    Karniol, Rachel; Reichman, Shiri; Fund, Liat

    2000-01-01

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

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

    ERIC Educational Resources Information Center

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

    2013-01-01

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

  13. 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…

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

    ERIC Educational Resources Information Center

    Kamran, Saeedeh Karbalaee; Maftoon, Parviz

    2012-01-01

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

  15. 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…

  16. 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,…

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

    ERIC Educational Resources Information Center

    Jarvikivi, Juhani; Pyykkonen, Pirita; Niemi, Jussi

    2009-01-01

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

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

    ERIC Educational Resources Information Center

    Oaks, Dallin D.

    1995-01-01

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

  19. 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

  20. 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…

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

    ERIC Educational Resources Information Center

    Valutis, Stephanie A.

    2015-01-01

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

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

    ERIC Educational Resources Information Center

    Karniol, Rachel; Reichman, Shiri; Fund, Liat

    2000-01-01

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

  3. 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…

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

    ERIC Educational Resources Information Center

    Valutis, Stephanie A.

    2015-01-01

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

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

    ERIC Educational Resources Information Center

    Stoycheva, Katya

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

  6. 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…

  7. 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…

  8. 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,

  9. 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…

  10. 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

  11. 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…

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

    ERIC Educational Resources Information Center

    Tsang, Yiu-Kei; Chen, Hsuan-Chih

    2013-01-01

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

  13. Morpho-Semantic Processing in Word Recognition: Evidence from Balanced and Biased Ambiguous Morphemes

    ERIC Educational Resources Information Center

    Tsang, Yiu-Kei; Chen, Hsuan-Chih

    2013-01-01

    The role of morphemic meaning in Chinese word recognition was examined with the masked and unmasked priming paradigms. Target words contained ambiguous morphemes biased toward the dominant or the subordinate meanings. Prime words either contained the same ambiguous morphemes in the subordinate interpretations or were unrelated to the targets. In…

  14. 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…

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

    ERIC Educational Resources Information Center

    Roncaglia-Denissen, M. Paula; Schmidt-Kassow, Maren; Heine, Angela; Kotz, Sonja A.

    2015-01-01

    In an event-related potential (ERP) study we investigated the role of age of acquisition (AoA) on the use of second language rhythmic properties during syntactic ambiguity resolution. Syntactically ambiguous sentences embedded in rhythmically regular and irregular contexts were presented to Turkish early and late second language (L2) learners of…

  16. Confronting the "F" Word: The Effects of Gender, Ambiguity, and Individual Difference Variables on Non-Targets' Confrontation of Heterosexist Comments.

    PubMed

    Weber, Danielle M; Dickter, Cheryl L

    2015-01-01

    The present study used an experimental setting to examine individual and situational variables that influence the confronting of heterosexist remarks by non-target heterosexuals. College student participants (n=120) responded to a heterosexist comment made in an online setting in which the ambiguity of the heterosexist remark was manipulated. Results indicated that the effect of the ambiguity of the comment on confronting behavior was moderated by individual differences in optimism. Confronting was also affected by sexual prejudice and experience with gay and lesbian individuals. In addition, females confronted more often and more strongly than males, especially following negative affective responses to the comment. PMID:26073029

  17. Ambiguity tolerance in organizations: definitional clarification and perspectives on future research

    PubMed Central

    McLain, David L.; Kefallonitis, Efstathios; Armani, Kimberly

    2015-01-01

    Ambiguity tolerance is an increasingly popular subject for study in a wide variety of fields. The definition of ambiguity tolerance has changed since its inception, and accompanying that change are changes in measurement and the research questions that interest researchers. There is a wealth of opportunity for research related to ambiguity tolerance and recent advances in neuroscience, measurement, trait research, perception, problem solving, and other fields highlight areas of interest and point to issues that need further attention. The future of ambiguity tolerance research is promising and it is expected that future studies will yield new insights into individual differences in reactions to the complex, unfamiliar, confusing, indeterminate, and incomplete stimuli that fall within the conceptual domain of ambiguity. PMID:25972818

  18. 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

  19. Spaceborne Hybrid Quad-Pol SAR Range Ambiguity Analysis and Simulations

    NASA Astrophysics Data System (ADS)

    Yang, Shilin; Li, Yang; Zhang, Jingjing; Hong, Wen

    2014-11-01

    The higher levels of range ambiguities in the cross-polarized measurement channels are the primary limitations for the matched quad-pol (e.g., HH, VV, VH, and HV) spaceborne synthetic aperture radar (SAR) systems. These ambiguities severely constrain the useful range of incident angles and the swath widths particularly at larger incidence. Adopting hybridpolarimetric architecture can remarkably reduce these ambiguities. In this paper, we analyse and develop the expression of range ambiguity to signal ratio (RASR) in the hybrid-polarimetric architecture. Simulations are made to testify this novel architecture’s advantage in the improvement of range ambiguities. The system operating parameters are derived from NASA’s DESDynl mission. In addition, we used the second order moments of polarimetric covariance matrices to depict target or the environment which are more precisely.

  20. Ambiguity tolerance in organizations: definitional clarification and perspectives on future research.

    PubMed

    McLain, David L; Kefallonitis, Efstathios; Armani, Kimberly

    2015-01-01

    Ambiguity tolerance is an increasingly popular subject for study in a wide variety of fields. The definition of ambiguity tolerance has changed since its inception, and accompanying that change are changes in measurement and the research questions that interest researchers. There is a wealth of opportunity for research related to ambiguity tolerance and recent advances in neuroscience, measurement, trait research, perception, problem solving, and other fields highlight areas of interest and point to issues that need further attention. The future of ambiguity tolerance research is promising and it is expected that future studies will yield new insights into individual differences in reactions to the complex, unfamiliar, confusing, indeterminate, and incomplete stimuli that fall within the conceptual domain of ambiguity. PMID:25972818

  1. A sequential and partial ambiguity resolution strategy for improving the initialization performance of medium-baseline relative positioning

    NASA Astrophysics Data System (ADS)

    Zhang, Shoujian; Zhao, Lei; Li, Xintan; Cheng, Bing

    2016-02-01

    Ionosphere products that are relatively precise are available thanks to the efforts of the International GNSS Service (IGS), and it might be possible to obtain a high success rate for the fixed integer ambiguities for medium- or longer-baseline ambiguity resolution (AR) using the ionosphere products as a priori information constraints. In this study, we used the IGS precise ionosphere products as a priori information before forming double-difference (DD) measurement equations using only original observables in a mid-range relative positioning and estimated the ionosphere residuals explicitly after DD. Furthermore, we proposed a sequential and partial ambiguity resolution (SPAR) strategy under the integer least square condition to realize fast and reliable AR. To demonstrate our proposed strategy, we randomly selected seven baselines ranging from 30 to 111 km and undertook positioning in a post-processing mode using real GPS dual-frequency data. According to the results, the SPAR strategy has a faster convergence process compared with batch AR. For instance, the convergence time with >90 % cumulative frequency percentage (probability) for 30, 40, 56, 66, 80, 95, and 111 km baselines was advanced by 55, 50, >75, 85, >110, 65, and >35 epochs, respectively, with a 30-s sample interval. By considering ionospheric correction before DD, we found further improvement in the initialization performance with the use of the SPAR strategy.

  2. On the ambiguity of the reaction rate constants in multivariate curve resolution for reversible first-order reaction systems.

    PubMed

    Schröder, Henning; Sawall, Mathias; Kubis, Christoph; Selent, Detlef; Hess, Dieter; Franke, Robert; Börner, Armin; Neymeyr, Klaus

    2016-07-13

    If for a chemical reaction with a known reaction mechanism the concentration profiles are accessible only for certain species, e.g. only for the main product, then often the reaction rate constants cannot uniquely be determined from the concentration data. This is a well-known fact which includes the so-called slow-fast ambiguity. This work combines the question of unique or non-unique reaction rate constants with factor analytic methods of chemometrics. The idea is to reduce the rotational ambiguity of pure component factorizations by considering only those concentration factors which are possible solutions of the kinetic equations for a properly adapted set of reaction rate constants. The resulting set of reaction rate constants corresponds to those solutions of the rate equations which appear as feasible factors in a pure component factorization. The new analysis of the ambiguity of reaction rate constants extends recent research activities on the Area of Feasible Solutions (AFS). The consistency with a given chemical reaction scheme is shown to be a valuable tool in order to reduce the AFS. The new methods are applied to model and experimental data. PMID:27237834

  3. Source estimation with surface-related multiples—fast ambiguity-resolved seismic imaging

    NASA Astrophysics Data System (ADS)

    Tu, Ning; Aravkin, Aleksandr; van Leeuwen, Tristan; Lin, Tim; Herrmann, Felix J.

    2016-03-01

    We address the problem of obtaining a reliable seismic image without prior knowledge of the source wavelet, especially from data that contain strong surface-related multiples. Conventional reverse-time migration requires prior knowledge of the source wavelet, which is either technically or computationally challenging to accurately determine; inaccurate estimates of the source wavelet can result in seriously degraded reverse-time migrated images, and therefore wrong geological interpretations. To solve this problem, we present a "wavelet-free" imaging procedure that simultaneously inverts for the source wavelet and the seismic image, by tightly integrating source estimation into a fast least-squares imaging framework, namely compressive imaging, given a reasonably accurate background velocity model. However, this joint inversion problem is difficult to solve as it is plagued with local minima and the ambiguity with respect to amplitude scalings, because of the multiplicative, and therefore nonlinear, appearance of the source wavelet in the otherwise linear formalism. We have found a way to solve this nonlinear joint-inversion problem using a technique called variable projection, and a way to overcome the scaling ambiguity by including surface-related multiples in our imaging procedure following recent developments in surface-related multiple prediction by sparse inversion. As a result, we obtain without prior knowledge of the source wavelet high-resolution seismic images, comparable in quality to images obtained assuming the true source wavelet is known. By leveraging the computationally efficient compressive-imaging methodology, these results are obtained at affordable computational costs compared with conventional processing work flows that include surface-related multiple removal and reverse-time migration.

  4. Source estimation with surface-related multiples—fast ambiguity-resolved seismic imaging

    NASA Astrophysics Data System (ADS)

    Tu, Ning; Aravkin, Aleksandr; van Leeuwen, Tristan; Lin, Tim; Herrmann, Felix J.

    2016-06-01

    We address the problem of obtaining a reliable seismic image without prior knowledge of the source wavelet, especially from data that contain strong surface-related multiples. Conventional reverse-time migration requires prior knowledge of the source wavelet, which is either technically or computationally challenging to accurately determine; inaccurate estimates of the source wavelet can result in seriously degraded reverse-time migrated images, and therefore wrong geological interpretations. To solve this problem, we present a `wavelet-free' imaging procedure that simultaneously inverts for the source wavelet and the seismic image, by tightly integrating source estimation into a fast least-squares imaging framework, namely compressive imaging, given a reasonably accurate background velocity model. However, this joint inversion problem is difficult to solve as it is plagued with local minima and the ambiguity with respect to amplitude scalings because of the multiplicative, and therefore nonlinear, appearance of the source wavelet in the otherwise linear formalism. We have found a way to solve this nonlinear joint-inversion problem using a technique called variable projection, and a way to overcome the scaling ambiguity by including surface-related multiples in our imaging procedure following recent developments in surface-related multiple prediction by sparse inversion. As a result, we obtain without prior knowledge of the source wavelet high-resolution seismic images, comparable in quality to images obtained assuming the true source wavelet is known. By leveraging the computationally efficient compressive-imaging methodology, these results are obtained at affordable computational costs compared with conventional processing work flows that include surface-related multiple removal and reverse-time migration.

  5. Remediation of context-processing deficits in schizophrenia: preliminary data with ambiguous sentences

    PubMed Central

    Besche-Richard, Chrystel; Terrien, Sarah; Lesgourgues, Marion; Béchiri-Payet, Célia; Gierski, Fabien; Limosin, Frédéric

    2014-01-01

    Background Processing of contextual information is essential for the establishment of good interpersonal relations and communicational interactions. Nevertheless, it is known that schizophrenic patients present impairments in the processing of contextual information. The aim of this study is to explore the influence of the remediation of context processing in schizophrenic patients. Methods Thirty-one schizophrenic patients and 28 matched healthy participants were included in this study. All participants were assessed on verbal knowledge (Mill-Hill test) and depression intensity (Beck Depression Scale 21 items). Schizophrenic patients were also assessed on thought, language, and communication disorders (Thought, Language and Communication scale). All participants completed a disambiguation task with two different levels of contextualization (high or low context) and a context-processing remediation task containing social scenarios that included ambiguous words and were presented with two different types of instruction: with or without context explanation. Results For the disambiguation task, results showed no effect of group, but a main effect of context, with better performances in the high-context than the low-context condition. For the context-processing remediation task, results showed a main effect of group: The performance of schizophrenic patients who had received explanations differed from that both of healthy participants and of schizophrenic patients who had not received explanations. Conclusion This study revealed that for all participants, the structuring of context had a positive effect on the contextual integration of ambiguous words. Concerning the remediation task, explanations about the strategies that could be used to take context into account improved the schizophrenic patients’ performances. This allows us to consider new methods of remediation that could improve social interaction in schizophrenia. PMID:25516712

  6. 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

  7. Prosodic facilitation in the resolution of syntactic ambiguities in subjects with left and right hemisphere damage.

    PubMed

    Walker, J P; Fongemie, K; Daigle, T

    2001-08-01

    The purpose of this study was to determine if prosody facilitates the comprehension of sentences containing temporary syntactic ambiguities in control, and left (LHD) and right hemisphere damaged (RHD) subjects. To test for effects of prosodic facilitation, sentences were created where prosodic boundaries coincided with (cooperating), were absent (baseline), or conflicted (conflicting) with syntactic boundaries in three response times (RTs) experiments. Despite differences in overall RTs and response accuracy for each group, all three groups responded faster and more accurately to sentences in the cooperating than in the baseline and conflicting conditions across experiments, indicating that prosody facilitates syntactic parsing in brain-damaged subjects just as it does with normal control subjects. Results are discussed in relation to psycholinguistic theories of syntactic parsing and neurolinguistic theories of hemispheric specialization in processing the acoustic properties of prosodic structures. PMID:11500068

  8. 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

  9. A girl with tomboy behavior: lesson from misdiagnosis in a baby with ambiguous genitalia.

    PubMed

    Dati, E; Baldinotti, F; Conidi, M E; Simi, P; Baroncelli, G I; Bertelloni, Silvano

    2010-01-01

    5alpha-Reductase-2 deficiency is a rare 46,XY disorder of sex differentiation caused by mutations in the 5alpha-reductase type 2 gene. It presents at birth with variable degree of undervirilization. Here, a baby with 5alpha-reductase-2 deficiency and misdiagnosis of complete androgen insensitivity syndrome, female sex assignment and early gonadectomy is described. During primary school, the girl developed tomboy behavior. Molecular analysis demonstrated compound heterozygosity for 5alpha-reductase type 2 gene mutations (exon 2: Q126R; exon 4: H230P). This child underlines the need for adequate endocrine and genetic testing for a definite diagnosis before gender is assigned in children with ambiguous genitalia and surgical interventions are carried out. Inadequate work-up may result in inappropriate gender assignment in infancy with possible inferences on outcome. PMID:20051677

  10. Disambiguating ambiguous motion perception: what are the cues?

    PubMed Central

    Piedimonte, Alessandro; Woods, Adam J.; Chatterjee, Anjan

    2015-01-01

    Motion perception is a fundamental feature of the human visual system. As part of our daily life we often have to determine the direction of motion, even in ambiguous (AMB) situations. These situations force us to rely on exogenous cues, such as other environmental motion, and endogenous cues, such as our own actions, or previously learned experiences. In three experiments, we asked participants to report the direction of an AMB motion display, while manipulating exogenous and endogenous sources of information. Specifically, in all three experiments the exogenous information was represented by another motion cue while the endogenous cue was represented, respectively, by movement execution, movement planning, or a learned association about the motion display. Participants were consistently biased by less AMB motion cues in the environment when reporting the AMB target direction. In the absence of less AMB exogenous motion information, participants were biased by their motor movements and even the planning of such movements. However, when participants learned a specific association about the target motion, this acquired endogenous knowledge countered exogenous motion cues in biasing participants’ perception. Taken together, our findings demonstrate that we disambiguate AMB motion using different sources of exogenous and endogenous cues, and that learned associations may be particularly salient in countering the effects of environmental cues. PMID:26217257

  11. Ambiguous Melanocytic Tumors with loss of 3p21

    PubMed Central

    Yeh, Iwei; Mully, Thaddeus W.; Wiesner, Thomas; Vemula, Swapna S.; Mirza, Sonia A.; Sparatta, Alyssa J.; McCalmont, Timothy H.; Bastian, Boris C.; LeBoit, Philip E.

    2014-01-01

    Germline loss of function mutations in BAP1 are associated with the development of cutaneous melanocytic tumors with some histopathologic characteristics seen in Spitz nevi. Similar melanocytic tumors occurring in a sporadic setting have been demonstrated to have biallelic loss of BAP1. In some of these sporadic tumors, loss of BAP1 occurs through mutation of one allele and genomic loss of the other. We screened our database of comparative genomic hybridization profiles of ambiguous melanocytic tumors to identify cases with a single genomic event involving loss of the BAP1 locus. The prevalence of tumors with a single genomic event involving loss of BAP1 was 6.7% in our study population. We further characterized the BAP1 status in 17 of these tumors with available additional material, confirming loss of BAP1 in all cases. We describe BAP1 loss in a blue nevus like melanoma and further expand the histopathologic spectrum of spitzoid melanocytic neoplasms with BAP1 loss. PMID:24705312

  12. Ambiguous melanocytic tumors with loss of 3p21.

    PubMed

    Yeh, Iwei; Mully, Thaddeus W; Wiesner, Thomas; Vemula, Swapna S; Mirza, Sonia A; Sparatta, Alyssa J; McCalmont, Timothy H; Bastian, Boris C; LeBoit, Philip E

    2014-08-01

    Germline loss-of-function mutations in BAP1 are associated with the development of cutaneous melanocytic tumors with some histopathologic characteristics seen in Spitz nevi. Similar melanocytic tumors occurring in a sporadic setting have been demonstrated to have biallelic loss of BAP1. In some of these sporadic tumors, loss of BAP1 occurs through mutation of 1 allele and genomic loss of the other. We screened our database of comparative genomic hybridization profiles of ambiguous melanocytic tumors to identify cases with a single genomic event involving loss of the BAP1 locus. The prevalence of tumors with a single genomic event involving loss of BAP1 was 6.7% in our study population. We further characterized the BAP1 status in 17 of these tumors with available additional material, confirming loss of BAP1 in all cases. We describe BAP1 loss in a blue nevus-like melanoma and further expand the histopathologic spectrum of spitzoid melanocytic neoplasms with BAP1 loss. PMID:24705312

  13. 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.

  14. Uncertainty As Knowledge: Harnessing Ambiguity and Uncertainty into Policy Constraints

    NASA Astrophysics Data System (ADS)

    Lewandowsky, S.; Risbey, J.

    2014-12-01

    There are numerous sources of uncertainty that impact policy decisions relating to climate change: There is scientific uncertainty, as for example encapsulated in estimates of climate sensitivity. There is policy uncertainty, which arises when mitigation efforts are erratic or are reversed (as recently happened in Australia). There is also technological uncertainty which affects the mitigation pathway. How can policy decisions be informed in light of these multiple sources of uncertainty? We propose an "ordinal" approach that relies on comparisons such as "greater than" or "lesser than" (known as ordinal), which can help sidestep disagreement about specific parameter estimates (e.g., climate sensitivity). To illustrate, recent analyses (Lewandowsky et al., 2014, Climatic Change) have shown that the magnitude of uncertainty about future temperature increases is directly linked with the magnitude of future risk: the greater the uncertainty, the greater the risk of mitigation failure (defined as exceeding a carbon budget for a predetermined threshold). Here we extend this approach to other sources of uncertainty, with a particular focus on "ambiguity" or "second-order" uncertainty, which arises when there is dissent among experts.

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

    PubMed

    Clément, Gilles; Wood, Scott J

    2014-01-01

    The central nervous system must resolve the ambiguity of inertial motion sensory cues in order to derive an accurate representation of spatial orientation. Adaptive changes during spaceflight in how the brain integrates vestibular cues with other sensory information can lead to impaired movement coordination, vertigo, spatial disorientation, and perceptual illusions after return to Earth. The purpose of this study was to compare tilt and translation motion perception in astronauts before and after returning from spaceflight. We hypothesized that these stimuli would be the most ambiguous in the low-frequency range (i.e., at about 0.3 Hz) where the linear acceleration can be interpreted either as a translation or as a tilt relative to gravity. Verbal reports were obtained in eleven astronauts tested using a motion-based tilt-translation device and a variable radius centrifuge before and after flying for two weeks on board the Space Shuttle. Consistent with previous studies, roll tilt perception was overestimated shortly after spaceflight and then recovered with 1-2 days. During dynamic linear acceleration (0.15-0.6 Hz, ±1.7 m/s2) perception of translation was also overestimated immediately after flight. Recovery to baseline was observed after 2 days for lateral translation and 8 days for fore-aft translation. These results suggest that there was a shift in the frequency dynamic of tilt-translation motion perception after adaptation to weightlessness. These results have implications for manual control during landing of a space vehicle after exposure to microgravity, as it will be the case for human asteroid and Mars missions. PMID:25354042

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

    PubMed

    Fürstenau, 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 μ, 0 ≤ μ ≤ 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

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

    PubMed Central

    Clément, Gilles; Wood, Scott J.

    2014-01-01

    The central nervous system must resolve the ambiguity of inertial motion sensory cues in order to derive an accurate representation of spatial orientation. Adaptive changes during spaceflight in how the brain integrates vestibular cues with other sensory information can lead to impaired movement coordination, vertigo, spatial disorientation, and perceptual illusions after return to Earth. The purpose of this study was to compare tilt and translation motion perception in astronauts before and after returning from spaceflight. We hypothesized that these stimuli would be the most ambiguous in the low-frequency range (i.e., at about 0.3 Hz) where the linear acceleration can be interpreted either as a translation or as a tilt relative to gravity. Verbal reports were obtained in eleven astronauts tested using a motion-based tilt-translation device and a variable radius centrifuge before and after flying for two weeks on board the Space Shuttle. Consistent with previous studies, roll tilt perception was overestimated shortly after spaceflight and then recovered with 1–2 days. During dynamic linear acceleration (0.15–0.6 Hz, ±1.7 m/s2) perception of translation was also overestimated immediately after flight. Recovery to baseline was observed after 2 days for lateral translation and 8 days for fore–aft translation. These results suggest that there was a shift in the frequency dynamic of tilt-translation motion perception after adaptation to weightlessness. These results have implications for manual control during landing of a space vehicle after exposure to microgravity, as it will be the case for human asteroid and Mars missions. PMID:25354042

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

    PubMed

    Mears, Carolyn Lunsford

    2008-01-01

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

  19. Still Giving Thanks for Good Health

    NASA Technical Reports Server (NTRS)

    2005-01-01

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

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

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

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

  20. 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…

  1. When in doubt, seize the day? Security values, prosocial values, and proactivity under ambiguity.

    PubMed

    Grant, Adam M; Rothbard, Nancy P

    2013-09-01

    Researchers have suggested that both ambiguity and values play important roles in shaping employees' proactive behaviors, but have not theoretically or empirically integrated these factors. Drawing on theories of situational strength and values, we propose that ambiguity constitutes a weak situation that strengthens the relationship between the content of employees' values and their proactivity. A field study of 204 employees and their direct supervisors in a water treatment plant provided support for this contingency perspective. Ambiguity moderated the relationship between employees' security and prosocial values and supervisor ratings of proactivity. Under high ambiguity, security values predicted lower proactivity, whereas prosocial values predicted higher proactivity. Under low ambiguity, values were not associated with proactivity. We replicated these findings in a laboratory experiment with 232 participants in which we measured proactivity objectively as initiative taken to correct errors: Participants with strong security values were less proactive, and participants with strong prosocial values were more proactive, but only when performance expectations were ambiguous. We discuss theoretical implications for research on proactivity, values, and ambiguity and uncertainty. PMID:23627604

  2. 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

  3. 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

  4. [The ambiguous concept of predialysis: proposal for a model].

    PubMed

    Alberghini, Elena; Gambirasio, Maria Cristina; Sarcina, Cristina; Biazzi, Cecilia; Ferrario, Francesca; Corghi, Enzo; Baragetti, Ivano; Buzzi, Laura; Visciano, Bianca; Terraneo, Veronica; Santagostino, Gaia; Pozzi, Claudio

    2011-01-01

    In 2009, 90% of nephrology centers in Lombardy declared to have a ''predialysis'' outpatient department, without, however, specifying its meaning. Research carried out in 2008 among nephrology centers in Piemonte showed how ambiguous this term was. According to the 2007 EDTA-ERA Registry, about 68% of European nephrology centers stated that they had an outpatient department for stage 4-5 CKD patients, but no information was available about the role of patients in the choice of dialysis. It is known that when the predialysis phase is poorly managed, the patient's rehabilitation will be more difficult. Dissatisfaction with dialysis often leads to withdrawal from dialysis, as several registries have shown. For this reason, we created a predialysis course at our center, involving a nephrologist, a nurse, and a dietician. The nephrologist helps the patient choose the most suitable therapeutic strategy, which means that doctor and patient share the responsibility for the treatment choice. The offered options are hemodialysis, peritoneal dialysis, preemptive kidney transplant, and a conservative dietary-pharmacological program. The nurse plans at least 4 meetings: 1) to talk with the patient in order to get to know him or her and his/her family; 2) to provide information about the dialysis procedure and establish the patient's preferences; 3) to clear any doubts about the treatment and deliver a booklet with information about the chosen dialysis procedure; 4) to explain the chosen dialysis procedure; 5) to meet the patient after their preparation for dialysis (vascular access or peritoneal catheter). The dietician manages the dietary programs both for patients who are close to starting dialysis and those on a longlasting conservative program. The predialysis course includes a meeting among all those involved with the patient (nephrologists, nurses, dieticians) to exchange information with the purpose of shared evaluation and decision-making. PMID:22028269

  5. Processing ambiguous Spanish se in a minimal chain.

    PubMed

    Meseguer, Enrique; Acuña-Fariña, Carlos; Carreiras, Manuel

    2009-04-01

    The recovery of pieces of information that are not linguistically expressed is a constant feature of the process of language comprehension. In the processing literature, such missing information is generally referred to as "gaps". Usually, one resolves gaps by finding "fillers" in either the sentence or the context. For instance, in Peter seemed to be upset, Peter is really the subject of being upset but appears as surface subject of seems. Sometimes constituents move, leaving gaps behind. Various Romance languages such as Spanish or Italian have a grammatical particle se/si, which, as it is extremely ambiguous, licenses different sorts of gaps. In Spanish, se can encode at least reflexive, impersonal, and passive meanings. In an eye-tracking experiment we contrast reflexive structures containing postverbal subjects with impersonal structures with no subjects (GAP se vendó apresuradamente el corredor/"the runner bandaged himself hurriedly" vs. GAP se vendó apresuradamente al corridor/"(someone) bandaged the runner hurriedly"). In a second manipulation we contrast the presence of an extra argument with se-passives (GAP se vendó el tobillo el corredor/"the runner bandaged his ankle" vs. GAP se vendó el tobillo al corridor/"the runner's ankle was bandaged"). Our comparisons involve contrasting standard transitive structures with nonstandard word order (postverbal subject and a preverbal subject gap) against inherently complex and less habitual structures such as impersonals (with no subject) or se-passives (with subjects in canonical object position). We evaluate the minimal chain principle (de Vincenzi, 1991), according to which displacement is costly because it entails complex (derivational) "chains" that must be undone before phrasal packaging can commence. We show the minimal chain principle to be essentially correct when contrasting more complex but more frequent structures with less complex but less frequent structures. A noteworthy feature of this research is that the gaps appear before the fillers in the structures that we analyse. PMID:18720277

  6. Resolution of a phase ambiguity in a calibration procedure for polarimetric radar systems

    SciTech Connect

    Sletten, M.A. . Radar Div.)

    1994-01-01

    In response to the remote sensing communities' interest in radar polarimetry, considerable effort has recently been devoted to the development of calibration techniques for polarimetric radar systems. A cross-pol/co-pol phase ambiguity in a previously published calibration procedure for polarimetric radar systems is discussed. The original procedure is modified to resolve the ambiguity while still retaining insensitivity to calibration target orientation. The modified form is then generalized and applied to an ultrawideband radar system for which the ambiguity in the original procedure is particularly evident.

  7. Using uniformat and gene[rate] to Analyze Data with Ambiguities in Population Genetics

    PubMed Central

    Nunes, José Manuel

    2015-01-01

    Some genetic systems frequently present ambiguous data that cannot be straightforwardly analyzed with common methods of population genetics. Two possibilities arise to analyze such data: one is the arbitrary simplification of the data and the other is the development of methods adapted to such ambiguous data. In this article, we present an attempt at such a development, the uniformat grammar and The gene[rate] tools, highlighting the specific aspects and the adaptations required to analyze ambiguous nominal data in population genetics. PMID:26917942

  8. Pipe flow measurements of turbulence and ambiguity using laser-Doppler velocimetry

    NASA Technical Reports Server (NTRS)

    Berman, N. S.; Dunning, J. W.

    1973-01-01

    The laser-Doppler ambiguities predicted by George and Lumley (1973) have been verified experimentally for turbulent pipe flows. Experiments were performed at Reynolds numbers from 5000 to 15,000 at the center line and near the wall. Ambiguity levels were measured from power spectral densities of FM demodulated laser signals and were compared with calculations based on the theory. The turbulent spectra for these water flows after accounting for the ambiguity were equivalent to hot-film measurements at similar Reynolds numbers. The feasibility of laser-Doppler measurements very close to the wall in shear flows is demonstrated.

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Using mutagenized Kluyveromyces marxianus strains (WT, 7-1, 8-1) we wish to find out the variable numbered tandem repeats (VNTR) of each of the DNA strains from the different mutagenized K. marxianus strains. To do this we used Phusion HF Buffer Pack to try and give a clear picture of the VNTR by u...

  10. Ambiguity involving two illusory melodies induced by a simple configuration of tones.

    PubMed

    Nemoto, Iku; Yuhara, Ryosuke

    2015-08-01

    Auditory scene analysis is essential in daily life to extract necessary information from complex acoustic environment and also from intricate development of music compositions. Auditory illusions and ambiguity are important factors in auditory scene analysis and have been studied extensively. We here report a novel form of ambiguity involving two illusory melodies implied by a very simple stimulus consisting of two sustained tones of different frequencies and an intermittently repeated tone of a frequency between the sustained tones. The measured time elapsed before a first perception change showed that illusion, ambiguity and disambiguation actually took place. We anticipate that the proposed illusion and ambiguity will provide a well-controlled approach for behavioral and neurophysiological studies of music recognition because of the simplicity of stimulus. PMID:26737828

  11. Role conflict and ambiguity of CEOs in international joint ventures: a transaction cost perspective.

    PubMed

    Gong, Y; Shenkar, O; Luo, Y; Nyaw, M K

    2001-08-01

    Insights from transaction cost economics were used to study the boundary conditions underlying the role conflict and ambiguity of 265 CEOs in Chinese-based international joint ventures. Role conflict and ambiguity were lower when the contract between parents was more complete. Contract completeness fully mediated the effects of parent objective gap and parent formalization on role ambiguity but only partially so in the case of role conflict. Role conflict was lower when the foreign parent was dominant in the venture but higher when the local parent was dominant. Role conflict and ambiguity were inversely related to cultural distance. Neither construct had a detrimental effect on international joint venture performance. Implications for role theory are discussed. PMID:11519659

  12. 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.

  13. An Automated Ambiguity-Resolution Code for Hinode/SP Vector Magnetic Field Data

    NASA Astrophysics Data System (ADS)

    Leka, K. D.; Barnes, G.; Crouch, A.

    2009-12-01

    A fast, automated algorithm is presented for use in resolving the 180° ambiguity in vector magnetic field data, including those data from Hinode/Spectropolarimeter. The Fortran-based code is loosely based on the Minimum Energy Algorithm, and is distributed to provide ambiguity-resolved data for the general user community. Here we generally describe the released code (available at http://www.cora.nwra.com/AMBIG), examples of its performance and usage for Hinode/SP data.

  14. 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-Wübbena 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.

  15. Towards PPP-RTK: Ambiguity resolution in real-time precise point positioning

    NASA Astrophysics Data System (ADS)

    Geng, J.; Teferle, F. N.; Meng, X.; Dodson, A. H.

    2011-05-01

    Integer ambiguity resolution at a single station can be achieved by introducing predetermined uncalibrated phase delays (UPDs) into the float ambiguity estimates of precise point positioning (PPP). This integer resolution technique has the potential of leading to a PPP-RTK (real-time kinematic) model where PPP provides rapid convergence to a reliable centimeter-level positioning accuracy based on an RTK reference network. Nonetheless, implementing this model is technically subject to how rapidly we can fix wide-lane ambiguities, stabilize narrow-lane UPD estimates, and achieve the first ambiguity-fixed solution. To investigate these issues, we used 7 days of 1-Hz sampling GPS data at 91 stations across Europe. We find that at least 10 min of observations are required for most receiver types to reliably fix about 90% of wide-lane ambiguities corresponding to high elevations, and over 20 min to fix about 90% of those corresponding to low elevations. Moreover, several tens of minutes are usually required for a regional network before a narrow-lane UPD estimate stabilizes to an accuracy of far better than 0.1 cycles. Finally, for hourly data, ambiguity resolution can significantly improve the accuracy of epoch-wise position estimates from 13.7, 7.1 and 11.4 cm to 0.8, 0.9 and 2.5 cm for the East, North and Up components, respectively, but a few tens of minutes is required to achieve the first ambiguity-fixed solution. Therefore, from the timeliness aspect, our PPP-RTK model currently cannot satisfy the critical requirement of instantaneous precise positioning where ambiguity-fixed solutions have to be achieved within at most a few seconds. However, this model can still be potentially applied to some near-real-time remote sensing applications, such as the GPS meteorology.

  16. 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

  17. Doctoral Alumni Giving: Motivations for Donating to the University of Pennsylvania

    ERIC Educational Resources Information Center

    Mastroieni, Anita

    2010-01-01

    This study sought to ascertain the specific motivations behind doctoral alumni giving. Most U.S. colleges and universities depend on alumni giving to supplement revenues from tuition and governmental support; however, relatively little alumni giving is generated from PhD graduates. The result is untapped revenue for doctoral-granting institutions.…

  18. 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

  19. 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…

  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. Attitude Toward Ambiguity: Empirically Robust Factors in Self-Report Personality Scales.

    PubMed

    Lauriola, Marco; Foschi, Renato; Mosca, Oriana; Weller, Joshua

    2016-06-01

    Two studies were conducted to examine the factor structure of attitude toward ambiguity, a broad personality construct that refers to personal reactions to perceived ambiguous stimuli in a variety of context and situations. Using samples from two countries, Study 1 mapped the hierarchical structure of 133 items from seven tolerance-intolerance of ambiguity scales (N = 360, Italy; N = 306, United States). Three major factors-Discomfort with Ambiguity, Moral Absolutism/Splitting, and Need for Complexity and Novelty-were recovered in each country with high replicability coefficients across samples. In Study 2 (N = 405, Italian community sample; N =366, English native speakers sample), we carried out a confirmatory analysis on selected factor markers. A bifactor model had an acceptable fit for each sample and reached the construct-level invariance for general and group factors. Convergent validity with related traits was assessed in both studies. We conclude that attitude toward ambiguity can be best represented a multidimensional construct involving affective (Discomfort with Ambiguity), cognitive (Moral Absolutism/Splitting), and epistemic (Need for Complexity and Novelty) components. PMID:25818603

  2. 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

  3. The Advantage of Ambiguity? Enhanced Neural Responses to Multi-Stable Percepts Correlate with the Degree of Perceived Instability

    PubMed Central

    Dyson, Benjamin J.

    2011-01-01

    Artwork can often pique the interest of the viewer or listener as a result of the ambiguity or instability contained within it. Our engagement with uncertain sensory experiences might have its origins in early cortical responses, in that perceptually unstable stimuli might preclude neural habituation and maintain activity in early sensory areas. To assess this idea, participants engaged with an ambiguous visual stimulus wherein two squares alternated with one another, in terms of simultaneously opposing vertical and horizontal locations relative to fixation (i.e., stroboscopic alternating motion; von Schiller, 1933). At each trial, participants were invited to interpret the movement of the squares in one of five ways: traditional vertical or horizontal motion, novel clockwise or counter-clockwise motion, and, a free-view condition in which participants were encouraged to switch the direction of motion as often as possible. Behavioral reports of perceptual stability showed clockwise and counter-clockwise motion to possess an intermediate level of stability compared to relatively stable vertical and horizontal motion, and, relatively unstable motion perceived during free-view conditions. Early visual evoked components recorded at parietal–occipital sites such as C1, P1, and N1 modulated as a function of visual intention. Both at a group and individual level, increased perceptual instability was related to increased negativity in all three of these early visual neural responses. Engagement with increasingly ambiguous input may partly result from the underlying exaggerated neural response to it. The study underscores the utility of combining neuroelectric recording with the presentation of perceptually multi-stable yet physically identical stimuli, in revealing brain activity associated with the purely internal process of interpreting and appreciating the sensory world that surrounds us. PMID:21897812

  4. Sex-related functional asymmetry of the ventromedial prefrontal cortex in regard to decision-making under risk and ambiguity.

    PubMed

    Sutterer, Matthew J; Koscik, Timothy R; Tranel, Daniel

    2015-08-01

    Previous work has provided preliminary indication of sex-related functional asymmetry of the ventromedial prefrontal cortex (vmPFC) in social and emotional functions and complex decision-making. Findings have been inconsistent, and based on small numbers of patients. Given the rarity of these neurological cases, replicable results across studies are important to build evidence for sex-related functional asymmetry of the vmPFC. Here we used a sample of sixteen neurological patients with unilateral damage to the left or right vmPFC and examined differences between men and women on a task that probed decision-making under risk or decision-making under ambiguity. We found that men with right-hemisphere vmPFC damage and women with left-hemisphere vmPFC damage demonstrated significantly reduced aversion to risk and ambiguity. Men with damage to the left vmPFC and women with damage to the right vmPFC showed aversion to risk and ambiguity comparable to participants with left or right-sided brain damage outside the vmPFC, and to comparison participants without brain damage. Our results add to previous findings of sex-related functional asymmetry of the vmPFC in decision-making. Our study also replicates findings of no observable behavioral differences between men and women without neurological damage on tests of decision-making. This pattern of neurobiological divergence but behavioral convergence between men and women may reflect a complex interplay of neuroendocrine, developmental, and psychosocial factors. PMID:26111489

  5. Compliment-Giving among Filipino College Students: An Exploratory Study.

    ERIC Educational Resources Information Center

    Mojica, Leonisa A.

    2002-01-01

    Studies syntactic patterns in compliment-giving among Filipino students at six universities in Manila. Finds differences between male and female student compliment-giving patterns, such as greater frequency of female compliment-giving. Also finds sex differences in the purpose of compliment-giving. (PKP)

  6. Giving preschoolers choice increases sharing behavior.

    PubMed

    Chernyak, Nadia; Kushnir, Tamar

    2013-10-01

    Young children are remarkably prosocial, but the mechanisms driving their prosociality are not well understood. Here, we propose that the experience of choice is critically tied to the expression of young children's altruistic behavior. Three- and 4-year-olds were asked to allocate resources to an individual in need by making a costly choice (allocating a resource they could have kept for themselves), a noncostly choice (allocating a resource that would otherwise be thrown away), or no choice (following instructions to allocate the resource). We measured subsequent prosociality by allowing children to then allocate new resources to a new individual. Although the majority of children shared with the first individual, children who were given costly alternatives shared more with the new individual. Results are discussed in terms of a prosocial-construal hypothesis, which suggests that children rationally infer their prosociality through the process of making difficult, autonomous choices. PMID:23955355

  7. Giving students the run of sprinting models

    NASA Astrophysics Data System (ADS)

    Heck, André; Ellermeijer, Ton

    2009-11-01

    A biomechanical study of sprinting is an interesting task for students who have a background in mechanics and calculus. These students can work with real data and do practical investigations similar to the way sports scientists do research. Student research activities are viable when the students are familiar with tools to collect and work with data from sensors and video recordings and with modeling tools for comparing simulation and experimental results. This article describes a multipurpose system, named COACH, that offers a versatile integrated set of tools for learning, doing, and teaching mathematics and science in a computer-based inquiry approach. Automated tracking of reference points and correction of perspective distortion in videos, state-of-the-art algorithms for data smoothing and numerical differentiation, and graphical system dynamics based modeling are some of the built-in techniques that are suitable for motion analysis. Their implementation and their application in student activities involving models of running are discussed.

  8. 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.

  9. 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

  10. Resummation ambiguities in the Higgs transverse-momentum spectrum in the Standard Model and beyond

    NASA Astrophysics Data System (ADS)

    Bagnaschi, E.; Harlander, R. V.; Mantler, H.; Vicini, A.; Wiesemann, M.

    2016-01-01

    We study the prediction for the Higgs transverse momentum distribution in gluon fusion and focus on the problem of matching fixed- and all-order perturbative results. The main sources of matching ambiguities on this distribution are investigated by means of a twofold comparison. On the one hand, we present a detailed qualitative and quantitative comparison of two recently introduced algorithms for determining the matching scale [1, 2]. On the other hand, we apply the results of both methods to three widely used approaches for the resummation of logarithmically enhanced contributions at small transverse momenta: the MC@NLO and POWHEG Monte Carlo approaches, and analytic resummation. While the three sets of results are largely compatible in the low- p ⊥ region, they exhibit sizable differences at large p ⊥. We show that these differences can be significantly reduced by suitable modifications of formally subleading terms in the Monte Carlo implementations. We apply our study to the Standard Model Higgs boson and to the neutral Higgs bosons of the Two-Higgs-Doublet Model for representative scenarios of the parameter space, where the top- and bottom-quark diagrams enter the cross section at different strengths.

  11. 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.

  12. 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.

  13. Separable responses to error, ambiguity, and reaction time in cingulo-opercular task control regions.

    PubMed

    Neta, Maital; Schlaggar, Bradley L; Petersen, Steven E

    2014-10-01

    The dorsal anterior cingulate (dACC), along with the closely affiliated anterior insula/frontal operculum, have been demonstrated to show three types of task control signals across a wide variety of tasks. One of these signals, a transient signal that is thought to represent performance feedback, shows greater activity to error than correct trials. Other work has found similar effects for uncertainty/ambiguity or conflict, though some argue that dACC activity is, instead, modulated primarily by other processes more reflected in reaction time. Here, we demonstrate that, rather than a single explanation, multiple information processing operations are crucial to characterizing the function of these brain regions, by comparing operations within a single paradigm. Participants performed two tasks in an fMRI experimental session: (1) deciding whether or not visually presented word pairs rhyme, and (2) rating auditorily presented single words as abstract or concrete. A pilot was used to identify ambiguous stimuli for both tasks (e.g., word pair: BASS/GRACE; single word: CHANGE). We found greater cingulo-opercular activity for errors and ambiguous trials than clear/correct trials, with a robust effect of reaction time. The effects of error and ambiguity remained when reaction time was regressed out, although the differences decreased. Further stepwise regression of response consensus (agreement across participants for each stimulus; a proxy for ambiguity) decreased differences between ambiguous and clear trials, but left error-related differences almost completely intact. These observations suggest that trial-wise responses in cingulo-opercular regions monitor multiple performance indices, including accuracy, ambiguity, and reaction time. PMID:24887509

  14. Improvement of PPP-inferred tropospheric estimates by integer ambiguity resolution

    NASA Astrophysics Data System (ADS)

    Shi, J.; Gao, Y.

    2012-11-01

    Integer ambiguity resolution in Precise Point Positioning (PPP) can improve positioning accuracy and reduce convergence time. The decoupled clock model proposed by Collins (2008) has been used to facilitate integer ambiguity resolution in PPP, and research has been conducted to assess the model's potential to improve positioning accuracy and reduce positioning convergence time. In particular, the biggest benefits have been identified for the positioning solutions within short observation periods such as one hour. However, there is little work reported about the model's potential to improve the estimation of the tropospheric parameter within short observation periods. This paper investigates the effect of PPP ambiguity resolution on the accuracy of the tropospheric estimates within one hour. The tropospheric estimates with float and fixed ambiguities within one hour are compared to two external references. The first reference is the International GNSS Service (IGS) final troposphere product based on the PPP technique. The second reference is the Constellation Observing System for Meteorology Ionosphere and Climate (COSMIC) radio occultation (RO) event based on the atmospheric profiles along the signal travel path. A comparison among ten co-located ground-based GPS and space-based RO troposphere zenith path delays shows that the mean bias of the troposphere estimates with float ambiguities can be significantly reduced from 30.1 to 17.0 mm when compared to the IGS troposphere product and from 36.3 to 19.7 mm when compared to the COSMIC RO. The root mean square (RMS) accuracy improvement of the tropospheric parameters by the ambiguity resolution is 33.3% when compared to the IGS products and 44.3% when compared to the COSMIC RO. All these improvements are achieved within one hour, which indicates the promising prospect of adopting PPP integer ambiguity resolution for time-critical applications such as typhoon prediction.

  15. Johnny Depp, Reconsidered: How Category-Relative Processing Fluency Determines the Appeal of Gender Ambiguity.

    PubMed

    Owen, Helen E; Halberstadt, Jamin; Carr, Evan W; Winkielman, Piotr

    2016-01-01

    Individuals that combine features of both genders-gender blends-are sometimes appealing and sometimes not. Heretofore, this difference was explained entirely in terms of sexual selection. In contrast, we propose that part of individuals' preference for gender blends is due to the cognitive effort required to classify them, and that such effort depends on the context in which a blend is judged. In two studies, participants judged the attractiveness of male-female morphs. Participants did so after classifying each face in terms of its gender, which was selectively more effortful for gender blends, or classifying faces on a gender-irrelevant dimension, which was equally effortful for gender blends. In both studies, gender blends were disliked when, and only when, the faces were first classified by gender, despite an overall preference for feminine features in all conditions. Critically, the preferences were mediated by the effort of stimulus classification. The results suggest that the variation in attractiveness of gender-ambiguous faces may derive from context-dependent requirements to determine gender membership. More generally, the results show that the difficulty of resolving social category membership-not just attitudes toward a social category-feed into perceivers' overall evaluations toward category members. PMID:26845341

  16. 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.

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

    PubMed

    Renden, Peter G; Kerstens, Sander; Oudejans, Raôul R D; Cañal-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

  18. Johnny Depp, Reconsidered: How Category-Relative Processing Fluency Determines the Appeal of Gender Ambiguity

    PubMed Central

    Owen, Helen E.; Halberstadt, Jamin; Carr, Evan W.; Winkielman, Piotr

    2016-01-01

    Individuals that combine features of both genders–gender blends–are sometimes appealing and sometimes not. Heretofore, this difference was explained entirely in terms of sexual selection. In contrast, we propose that part of individuals’ preference for gender blends is due to the cognitive effort required to classify them, and that such effort depends on the context in which a blend is judged. In two studies, participants judged the attractiveness of male-female morphs. Participants did so after classifying each face in terms of its gender, which was selectively more effortful for gender blends, or classifying faces on a gender-irrelevant dimension, which was equally effortful for gender blends. In both studies, gender blends were disliked when, and only when, the faces were first classified by gender, despite an overall preference for feminine features in all conditions. Critically, the preferences were mediated by the effort of stimulus classification. The results suggest that the variation in attractiveness of gender-ambiguous faces may derive from context-dependent requirements to determine gender membership. More generally, the results show that the difficulty of resolving social category membership–not just attitudes toward a social category–feed into perceivers’ overall evaluations toward category members. PMID:26845341

  19. GLONASS fractional-cycle bias estimation across inhomogeneous receivers for PPP ambiguity resolution

    NASA Astrophysics Data System (ADS)

    Geng, Jianghui; Bock, Yehuda

    2016-04-01

    The key issue to enable precise point positioning with ambiguity resolution (PPP-AR) is to estimate fractional-cycle biases (FCBs), which mainly relate to receiver and satellite hardware biases, over a network of reference stations. While this has been well achieved for GPS, FCB estimation for GLONASS is difficult because (1) satellites do not share the same frequencies as a result of Frequency Division Multiple Access (FDMA) signals; (2) and even worse, pseudorange hardware biases of receivers vary in an irregular manner with manufacturers, antennas, domes, firmware, etc., which especially complicates GLONASS PPP-AR over inhomogeneous receivers. We propose a general approach where external ionosphere products are introduced into GLONASS PPP to estimate precise FCBs that are less impaired by pseudorange hardware biases of diverse receivers to enable PPP-AR. One month of GLONASS data at about 550 European stations were processed. From an exemplary network of 51 inhomogeneous receivers, including four receiver types with various antennas and spanning about 800 km in both longitudinal and latitudinal directions, we found that 92.4 % of all fractional parts of GLONASS wide-lane ambiguities agree well within ± 0.15 cycles with a standard deviation of 0.09 cycles if global ionosphere maps (GIMs) are introduced, compared to only 51.7 % within ± 0.15 cycles and a larger standard deviation of 0.22 cycles otherwise. Hourly static GLONASS PPP-AR at 40 test stations can reach position estimates of about 1 and 2 cm in RMS from ground truth for the horizontal and vertical components, respectively, which is comparable to hourly GPS PPP-AR. Integrated GLONASS and GPS PPP-AR can further achieve an RMS of about 0.5 cm in horizontal and 1-2 cm in vertical components. We stress that the performance of GLONASS PPP-AR across inhomogeneous receivers depends on the accuracy of ionosphere products. GIMs have a modest accuracy of only 2-8 TECU (Total Electron Content Unit) in vertical which confines PPP-AR to an approximately 800× 800 km area in Europe. We expect that a regional ionosphere map with a better than 1 TECU accuracy is likely to improve the GLONASS PPP-AR efficiency.

  20. GLONASS fractional-cycle bias estimation across inhomogeneous receivers for PPP ambiguity resolution

    NASA Astrophysics Data System (ADS)

    Geng, Jianghui; Bock, Yehuda

    2015-12-01

    The key issue to enable precise point positioning with ambiguity resolution (PPP-AR) is to estimate fractional-cycle biases (FCBs), which mainly relate to receiver and satellite hardware biases, over a network of reference stations. While this has been well achieved for GPS, FCB estimation for GLONASS is difficult because (1) satellites do not share the same frequencies as a result of Frequency Division Multiple Access (FDMA) signals; (2) and even worse, pseudorange hardware biases of receivers vary in an irregular manner with manufacturers, antennas, domes, firmware, etc., which especially complicates GLONASS PPP-AR over inhomogeneous receivers. We propose a general approach where external ionosphere products are introduced into GLONASS PPP to estimate precise FCBs that are less impaired by pseudorange hardware biases of diverse receivers to enable PPP-AR. One month of GLONASS data at about 550 European stations were processed. From an exemplary network of 51 inhomogeneous receivers, including four receiver types with various antennas and spanning about 800 km in both longitudinal and latitudinal directions, we found that 92.4 % of all fractional parts of GLONASS wide-lane ambiguities agree well within ± 0.15 cycles with a standard deviation of 0.09 cycles if global ionosphere maps (GIMs) are introduced, compared to only 51.7 % within ± 0.15 cycles and a larger standard deviation of 0.22 cycles otherwise. Hourly static GLONASS PPP-AR at 40 test stations can reach position estimates of about 1 and 2 cm in RMS from ground truth for the horizontal and vertical components, respectively, which is comparable to hourly GPS PPP-AR. Integrated GLONASS and GPS PPP-AR can further achieve an RMS of about 0.5 cm in horizontal and 1-2 cm in vertical components. We stress that the performance of GLONASS PPP-AR across inhomogeneous receivers depends on the accuracy of ionosphere products. GIMs have a modest accuracy of only 2-8 TECU (Total Electron Content Unit) in vertical which confines PPP-AR to an approximately 800× 800 km area in Europe. We expect that a regional ionosphere map with a better than 1 TECU accuracy is likely to improve the GLONASS PPP-AR efficiency.