Ambiguity Within Nursing Practice: An Evolutionary Concept Analysis.

Science.gov (United States)

McMahon, Michelle A; Dluhy, Nancy M

2017-02-01

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

Blue Creek Winter Range: Wildlife Mitigation Project. Final environmental assessment

International Nuclear Information System (INIS)

1994-11-01

Bonneville Power Administration (BPA) proposes to fund that portion of the Washington Wildlife Agreement pertaining to the Blue Creek Winter Range Wildlife Mitigation Project (Project) in a cooperative effort with the Spokane Tribe, Upper Columbia United Tribes, and the Bureau of Indian Affairs (BIA). If fully implemented, the proposed action would allow the sponsors to protect and enhance 2,631 habitat units of big game winter range and riparian shrub habitat on 2,185 hectares (5,400 acres) of Spokane Tribal trust lands, and to conduct long term wildlife management activities within the Spokane Indian Reservation project area. This Final Environmental Assessment (EA) examines the potential environmental effects of securing land and conducting wildlife habitat enhancement and long term management activities within the boundaries of the Spokane Indian Reservation. Four proposed activities (habitat protection, habitat enhancement, operation and maintenance, and monitoring and evaluation) are analyzed. The proposed action is intended to meet the need for mitigation of wildlife and wildlife habitat adversely affected by the construction of Grand Coulee Dam and its reservoir

Ontology: ambiguity and accuracy

Directory of Open Access Journals (Sweden)

Marcelo Schiessl

2012-08-01

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

Treatment decisions under ambiguity.

Science.gov (United States)

Berger, Loïc; Bleichrodt, Han; Eeckhoudt, Louis

2013-05-01

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

Image Ambiguity and Fluency

Science.gov (United States)

Jakesch, Martina; Leder, Helmut; Forster, Michael

2013-01-01

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

Hellsgate Winter Range : Wildlife Mitigation Project. Final Environmental Assessment.

Energy Technology Data Exchange (ETDEWEB)

United States. Bonneville Power Administration.

1995-03-01

Bonneville Power Administration (BPA) proposes to fund the Hellsgate Winter Range Wildlife Mitigation Project (Project) in a cooperative effort with the Colville Confederated Tribes and the Bureau of Indian Affairs (BIA). The proposed action would allow the sponsors to secure property and conduct wildlife management activities within the boundaries of the Colville Indian Reservation. This Final Environmental Assessment (EA) examines the potential environmental effects of acquiring and managing property for wildlife and wildlife habitat within a large project area. This area consists of several separated land parcels, of which 2,000 hectares (4,943 acres) have been purchased by BPA and an additional 4,640 hectares (11,466 acres) have been identified by the Colville Confederated Tribes for inclusion in the Project. Four proposed activities (habitat protection, habitat enhancement, operation and maintenance, and monitoring and evaluation) are analyzed. The proposed action is intended to meet the need for mitigation of wildlife and wildlife habitat that was adversely affected by the construction of Grand Coulee and Chief Joseph Dams and their reservoirs.

Hellsgate Winter Range: Wildlife mitigation project. Final environmental assessment

International Nuclear Information System (INIS)

1995-03-01

Bonneville Power Administration (BPA) proposes to fund the Hellsgate Winter Range Wildlife Mitigation Project (Project) in a cooperative effort with the Colville Confederated Tribes and the Bureau of Indian Affairs (BIA). The proposed action would allow the sponsors to secure property and conduct wildlife management activities within the boundaries of the Colville Indian Reservation. This Final Environmental Assessment (EA) examines the potential environmental effects of acquiring and managing property for wildlife and wildlife habitat within a large project area. This area consists of several separated land parcels, of which 2,000 hectares (4,943 acres) have been purchased by BPA and an additional 4,640 hectares (11,466 acres) have been identified by the Colville Confederated Tribes for inclusion in the Project. Four proposed activities (habitat protection, habitat enhancement, operation and maintenance, and monitoring and evaluation) are analyzed. The proposed action is intended to meet the need for mitigation of wildlife and wildlife habitat that was adversely affected by the construction of Grand Coulee and Chief Joseph Dams and their reservoirs

Measuring higher order ambiguity preferences.

Science.gov (United States)

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

2018-01-01

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

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

Science.gov (United States)

Robins, Simon

2010-01-01

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

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

Science.gov (United States)

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

2016-01-01

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

An integer ambiguity resolution method for the global positioning system (GPS)-based land vehicle attitude determination

International Nuclear Information System (INIS)

Wang, Bo; Miao, Lingjuan; Wang, Shunting; Shen, Jun

2009-01-01

During attitude determination using a global positioning system (GPS), cycle slips occur due to the loss of lock and noise disturbance. Therefore, the integer ambiguity needs re-computation to isolate the error in carrier phase. This paper presents a fast method for integer ambiguity resolution for land vehicle application. After the cycle slips are detected, the velocity vector is utilized to obtain the rough baseline vector. The obtained baseline vector is substituted into carrier phase observation equations to solve the float ambiguity solution which can be used as a constraint to accelerate the integer ambiguity search procedure at next epochs. The probability of correct integer estimation in the expanded search space is analyzed. Experimental results demonstrate that the proposed method gives a fast approach to obtain new fixed ambiguities while the regular method takes longer time and sometimes results in incorrect solutions

Measurement of vortex velocities over a wide range of vortex age, downstream distance and free stream velocity

Science.gov (United States)

Rorke, J. B.; Moffett, R. C.

1977-01-01

A wind tunnel test was conducted to obtain vortex velocity signatures over a wide parameter range encompassing the data conditions of several previous researchers while maintaining a common instrumentation and test facility. The generating wing panel was configured with both a revolved airfoil tip shape and a square tip shape and had a semispan aspect of 4.05/1.0 with a 121.9 cm span. Free stream velocity was varied from 6.1 m/sec to 76.2 m/sec and the vortex core velocities were measured at locations 3, 6, 12, 24 and 48 chordlengths downstream of the wing trailing edge, yielding vortex ages up to 2.0 seconds. Wing pitch angles of 6, 8, 9 and 12 deg were investigated. Detailed surface pressure distributions and wing force measurements were obtained for each wing tip configuration. Correlation with vortex velocity data taken in previous experiments is good. During the rollup process, vortex core parameters appear to be dependent primarily on vortex age. Trending in the plateau and decay regions is more complex and the machanisms appear to be more unstable.

Risk, ambiguity and sovereign rating

OpenAIRE

Di Caro, Paolo

2014-01-01

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

PRF Ambiguity Detrmination for Radarsat ScanSAR System

Science.gov (United States)

Jin, Michael Y.

1998-01-01

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

Risk, ambiguity, and diversification

OpenAIRE

Sautua, Santiago-Ignacio

2016-01-01

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

SAR Cross-Ambiguities in SAOCOM-CS Large Baseline Bistatic Configuration

OpenAIRE

Bordoni, Federica; Rodriguez-Cassola, Marc; Younis, Marwan; Prats-Iraola, Pau; Lopez-Dekker, Paco; Krieger, Gerhard

2016-01-01

The evaluation of the ambiguous signal level, the Ambiguity-to-Signal Ratio (ASR), plays a key role in the Synthetic Aperture Radar (SAR) design and performance prediction. In conventional SAR acquisition scenarios, the computation of the ASR is based on the evaluation of the range and azimuth ambiguous contributes. Though appealing for its simplicity, this approach could be inaccurate in case of complex SAR acquisition geometries. In this paper we focus on the ASR performance of the SAOCOM-...

Ambiguity of non-systematic chemical identifiers within and between small-molecule databases.

Science.gov (United States)

Akhondi, Saber A; Muresan, Sorel; Williams, Antony J; Kors, Jan A

2015-01-01

A wide range of chemical compound databases are currently available for pharmaceutical research. To retrieve compound information, including structures, researchers can query these chemical databases using non-systematic identifiers. These are source-dependent identifiers (e.g., brand names, generic names), which are usually assigned to the compound at the point of registration. The correctness of non-systematic identifiers (i.e., whether an identifier matches the associated structure) can only be assessed manually, which is cumbersome, but it is possible to automatically check their ambiguity (i.e., whether an identifier matches more than one structure). In this study we have quantified the ambiguity of non-systematic identifiers within and between eight widely used chemical databases. We also studied the effect of chemical structure standardization on reducing the ambiguity of non-systematic identifiers. The ambiguity of non-systematic identifiers within databases varied from 0.1 to 15.2 % (median 2.5 %). Standardization reduced the ambiguity only to a small extent for most databases. A wide range of ambiguity existed for non-systematic identifiers that are shared between databases (17.7-60.2 %, median of 40.3 %). Removing stereochemistry information provided the largest reduction in ambiguity across databases (median reduction 13.7 percentage points). Ambiguity of non-systematic identifiers within chemical databases is generally low, but ambiguity of non-systematic identifiers that are shared between databases, is high. Chemical structure standardization reduces the ambiguity to a limited extent. Our findings can help to improve database integration, curation, and maintenance.

Measuring higher order ambiguity preferences

NARCIS (Netherlands)

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

2017-01-01

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

Application of velocity filtering to optical-flow passive ranging

Science.gov (United States)

Barniv, Yair

1992-01-01

The performance of the velocity filtering method as applied to optical-flow passive ranging under real-world conditions is evaluated. The theory of the 3-D Fourier transform as applied to constant-speed moving points is reviewed, and the space-domain shift-and-add algorithm is derived from the general 3-D matched filtering formulation. The constant-speed algorithm is then modified to fit the actual speed encountered in the optical flow application, and the passband of that filter is found in terms of depth (sensor/object distance) so as to cover any given range of depths. Two algorithmic solutions for the problems associated with pixel interpolation and object expansion are developed, and experimental results are presented.

Ambiguous chair

DEFF Research Database (Denmark)

Manelius, Anne-Mette

2011-01-01

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

The Ethics of Ambiguity

Science.gov (United States)

2016-01-01

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

Exploring ambiguous realms

DEFF Research Database (Denmark)

Clemensen, Nana

2016-01-01

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

Mitigation of defocusing by statics and near-surface velocity errors by interferometric least-squares migration with a reference datum

KAUST Repository

Sinha, Mrinal

2016-05-23

Imaging seismic data with an erroneous migration velocity can lead to defocused migration images. To mitigate this problem, we first choose a reference reflector whose topography is well-known from the well logs, for example. Reflections from this reference layer are correlated with the traces associated with reflections from deeper interfaces to get crosscorrelograms. Interferometric least-squares migration (ILSM) is then used to get the migration image that maximizes the crosscorrelation between the observed and the predicted crosscorrelograms. Deeper reference reflectors are used to image deeper parts of the subsurface with a greater accuracy. Results on synthetic and field data show that defocusing caused by velocity errors is largely suppressed by ILSM. We have also determined that ILSM can be used for 4D surveys in which environmental conditions and acquisition parameters are significantly different from one survey to the next. The limitations of ILSM are that it requires prior knowledge of a reference reflector in the subsurface and the velocity model below the reference reflector should be accurate.

Shear wave velocity-based evaluation and design of stone column improved ground for liquefaction mitigation

Science.gov (United States)

Zhou, Yanguo; Sun, Zhengbo; Chen, Jie; Chen, Yunmin; Chen, Renpeng

2017-04-01

The evaluation and design of stone column improvement ground for liquefaction mitigation is a challenging issue for the state of practice. In this paper, a shear wave velocity-based approach is proposed based on the well-defined correlations of liquefaction resistance (CRR)-shear wave velocity ( V s)-void ratio ( e) of sandy soils, and the values of parameters in this approach are recommended for preliminary design purpose when site specific values are not available. The detailed procedures of pre- and post-improvement liquefaction evaluations and stone column design are given. According to this approach, the required level of ground improvement will be met once the target V s of soil is raised high enough (i.e., no less than the critical velocity) to resist the given earthquake loading according to the CRR- V s relationship, and then this requirement is transferred to the control of target void ratio (i.e., the critical e) according to the V s- e relationship. As this approach relies on the densification of the surrounding soil instead of the whole improved ground and is conservative by nature, specific considerations of the densification mechanism and effect are given, and the effects of drainage and reinforcement of stone columns are also discussed. A case study of a thermal power plant in Indonesia is introduced, where the effectiveness of stone column improved ground was evaluated by the proposed V s-based method and compared with the SPT-based evaluation. This improved ground performed well and experienced no liquefaction during subsequent strong earthquakes.

The Ethics of Ambiguity

Directory of Open Access Journals (Sweden)

Ronald E. Domen MD

2016-06-01

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

Ambiguity Resolution for Phase-Based 3-D Source Localization under Fixed Uniform Circular Array.

Science.gov (United States)

Chen, Xin; Liu, Zhen; Wei, Xizhang

2017-05-11

Under fixed uniform circular array (UCA), 3-D parameter estimation of a source whose half-wavelength is smaller than the array aperture would suffer from a serious phase ambiguity problem, which also appears in a recently proposed phase-based algorithm. In this paper, by using the centro-symmetry of UCA with an even number of sensors, the source's angles and range can be decoupled and a novel algorithm named subarray grouping and ambiguity searching (SGAS) is addressed to resolve angle ambiguity. In the SGAS algorithm, each subarray formed by two couples of centro-symmetry sensors can obtain a batch of results under different ambiguities, and by searching the nearest value among subarrays, which is always corresponding to correct ambiguity, rough angle estimation with no ambiguity is realized. Then, the unambiguous angles are employed to resolve phase ambiguity in a phase-based 3-D parameter estimation algorithm, and the source's range, as well as more precise angles, can be achieved. Moreover, to improve the practical performance of SGAS, the optimal structure of subarrays and subarray selection criteria are further investigated. Simulation results demonstrate the satisfying performance of the proposed method in 3-D source localization.

Theory-Based Evaluation Meets Ambiguity

DEFF Research Database (Denmark)

Dahler-Larsen, Peter

2017-01-01

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

Coding of level of ambiguity within neural systems mediating choice.

Science.gov (United States)

Lopez-Paniagua, Dan; Seger, Carol A

2013-01-01

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

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

Science.gov (United States)

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

2016-12-01

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

Influence of long-range Coulomb interaction in velocity map imaging.

Science.gov (United States)

Barillot, T; Brédy, R; Celep, G; Cohen, S; Compagnon, I; Concina, B; Constant, E; Danakas, S; Kalaitzis, P; Karras, G; Lépine, F; Loriot, V; Marciniak, A; Predelus-Renois, G; Schindler, B; Bordas, C

2017-07-07

The standard velocity-map imaging (VMI) analysis relies on the simple approximation that the residual Coulomb field experienced by the photoelectron ejected from a neutral or ion system may be neglected. Under this almost universal approximation, the photoelectrons follow ballistic (parabolic) trajectories in the externally applied electric field, and the recorded image may be considered as a 2D projection of the initial photoelectron velocity distribution. There are, however, several circumstances where this approximation is not justified and the influence of long-range forces must absolutely be taken into account for the interpretation and analysis of the recorded images. The aim of this paper is to illustrate this influence by discussing two different situations involving isolated atoms or molecules where the analysis of experimental images cannot be performed without considering long-range Coulomb interactions. The first situation occurs when slow (meV) photoelectrons are photoionized from a neutral system and strongly interact with the attractive Coulomb potential of the residual ion. The result of this interaction is the formation of a more complex structure in the image, as well as the appearance of an intense glory at the center of the image. The second situation, observed also at low energy, occurs in the photodetachment from a multiply charged anion and it is characterized by the presence of a long-range repulsive potential. Then, while the standard VMI approximation is still valid, the very specific features exhibited by the recorded images can be explained only by taking into consideration tunnel detachment through the repulsive Coulomb barrier.

Hellsgate Winter Range: Wildlife Mitigation Project. Final Environmental Assessment

International Nuclear Information System (INIS)

1995-03-01

BPA proposes to fund the Hellsgate Winter Range: Wildlife Mitigation Project (Project) in a cooperative effort with the Colville Confederated Tribes and the Bureau of Indian Affairs (BIA). The Project is intended to mitigate for wildlife and wildlife habitat adversely affected by the construction of Grand Coulee and Chief Joseph Dams and their reservoirs. The Project would allow the sponsors to secure land and conduct wildlife habitat improvement and long-term management activities within the boundaries of the Colville Indian Reservation. BPA has prepared an Environmental Assessment (EA) (DOE/EA-0940) evaluating the potential environmental effects of the proposed Project (Alternative B) and No Action (Alternative A). Protection and re-establishment of riparian and upland habitat on the Colville Indian Reservation, under Alternative B, would not have a significant adverse environmental impact because: (1) there would be only limited, mostly short-term adverse impacts on soils, water quality, air quality, vegetation, and wildlife (including no effect on endangered species); and (2) there would be no adverse effect on water quantity, cultural resources, or land use. Based on the analysis in the EA, BPA has determined that the proposed action is not a major Federal action significantly affecting the quality of the human environment, within the meaning of the National Environmental Policy Act (NEPA) of 1969. Therefore, the preparation of an Environmental Impact Statement (EIS) is not required and BPA is issuing this FONSI

An approach to improving transporting velocity in the long-range ultrasonic transportation of micro-particles

International Nuclear Information System (INIS)

Meng, Jianxin; Mei, Deqing; Yang, Keji; Fan, Zongwei

2014-01-01

In existing ultrasonic transportation methods, the long-range transportation of micro-particles is always realized in step-by-step way. Due to the substantial decrease of the driving force in each step, the transportation is lower-speed and stair-stepping. To improve the transporting velocity, a non-stepping ultrasonic transportation approach is proposed. By quantitatively analyzing the acoustic potential well, an optimal region is defined as the position, where the largest driving force is provided under the condition that the driving force is simultaneously the major component of an acoustic radiation force. To keep the micro-particle trapped in the optimal region during the whole transportation process, an approach of optimizing the phase-shifting velocity and phase-shifting step is adopted. Due to the stable and large driving force, the displacement of the micro-particle is an approximately linear function of time, instead of a stair-stepping function of time as in the existing step-by-step methods. An experimental setup is also developed to validate this approach. Long-range ultrasonic transportations of zirconium beads with high transporting velocity were realized. The experimental results demonstrated that this approach is an effective way to improve transporting velocity in the long-range ultrasonic transportation of micro-particles

Prerequisites for Accurate Monitoring of River Discharge Based on Fixed-Location Velocity Measurements

Science.gov (United States)

Kästner, K.; Hoitink, A. J. F.; Torfs, P. J. J. F.; Vermeulen, B.; Ningsih, N. S.; Pramulya, M.

2018-02-01

River discharge has to be monitored reliably for effective water management. As river discharge cannot be measured directly, it is usually inferred from the water level. This practice is unreliable at places where the relation between water level and flow velocity is ambiguous. In such a case, the continuous measurement of the flow velocity can improve the discharge prediction. The emergence of horizontal acoustic Doppler current profilers (HADCPs) has made it possible to continuously measure the flow velocity. However, the profiling range of HADCPs is limited, so that a single instrument can only partially cover a wide cross section. The total discharge still has to be determined with a model. While the limitations of rating curves are well understood, there is not yet a comprehensive theory to assess the accuracy of discharge predicted from velocity measurements. Such a theory is necessary to discriminate which factors influence the measurements, and to improve instrument deployment as well as discharge prediction. This paper presents a generic method to assess the uncertainty of discharge predicted from range-limited velocity profiles. The theory shows that a major source of error is the variation of the ratio between the local and cross-section-averaged velocity. This variation is large near the banks, where HADCPs are usually deployed and can limit the advantage gained from the velocity measurement. We apply our theory at two gauging stations situated in the Kapuas River, Indonesia. We find that at one of the two stations the index velocity does not outperform a simple rating curve.

Ambiguity aversion in rhesus macaques

Directory of Open Access Journals (Sweden)

Benjamin eHayden

2010-09-01

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

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

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

2017-07-01

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

Determinants of translation ambiguity

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

2016-01-01

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

Ambiguity Of Doppler Centroid In Synthetic-Aperture Radar

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Chang, Chi-Yung; Curlander, John C.

1991-01-01

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

Effective ambiguity checking in biosequence analysis

Directory of Open Access Journals (Sweden)

Giegerich Robert

2005-06-01

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

Sound velocity of tantalum under shock compression in the 18–142 GPa range

Energy Technology Data Exchange (ETDEWEB)

Xi, Feng, E-mail: xifeng@caep.cn; Jin, Ke; Cai, Lingcang, E-mail: cai-lingcang@aliyun.com; Geng, Huayun; Tan, Ye; Li, Jun [National Key Laboratory of Shock Waves and Detonation Physics, Institute of Fluid Physics, CAEP, P.O. Box 919-102 Mianyang, Sichuan 621999 (China)

2015-05-14

Dynamic compression experiments of tantalum (Ta) within a shock pressure range from 18–142 GPa were conducted driven by explosive, a two-stage light gas gun, and a powder gun, respectively. The time-resolved Ta/LiF (lithium fluoride) interface velocity profiles were recorded with a displacement interferometer system for any reflector. Sound velocities of Ta were obtained from the peak state time duration measurements with the step-sample technique and the direct-reverse impact technique. The uncertainty of measured sound velocities were analyzed carefully, which suggests that the symmetrical impact method with step-samples is more accurate for sound velocity measurement, and the most important parameter in this type experiment is the accurate sample/window particle velocity profile, especially the accurate peak state time duration. From these carefully analyzed sound velocity data, no evidence of a phase transition was found up to the shock melting pressure of Ta.

Engineering Polymer Blends for Impact Damage Mitigation

Science.gov (United States)

Gordon, Keith L.; Smith, Russell W.; Working, Dennis C.; Siochi, Emilie J.

2016-01-01

Structures containing polymers such as DuPont's Surlyn® 8940, demonstrate puncture healing when impacted by a 9 millimeter projectile traveling from speeds near 300 meters per second (1,100 feet per second) to hypervelocity impacts in the micrometeoroid velocity range of 5 kilometers per second (16,000 feet per second). Surlyn® 8940 puncture heals over a temperature range of minus 30 degrees Centigrade to plus 70 degrees Centigrade and shows potential for use in pressurized vessels subject to impact damage. However, such polymers are difficult to process and limited in applicability due to their low thermal stability, poor chemical resistance and overall poor mechanical properties. In this work, several puncture healing engineered melt formulations were developed. Moldings of melt blend formulations were impacted with a 5.56 millimeter projectile with a nominal velocity of 945 meters per second (3,100 feet per second) at about 25 degrees Centigrade, 50 degrees Centigrade and 100 degrees Centigrade, depending upon the specific blend being investigated. Self-healing tendencies were determined using surface vacuum pressure tests and tensile tests after penetration using tensile dog-bone specimens (ASTM D 638-10). For the characterization of tensile properties both pristine and impacted specimens were tested to obtain tensile modulus, yield stress and tensile strength, where possible. Experimental results demonstrate a range of new puncture healing blends which mitigate damage in the ballistic velocity regime.

Learning, Teaching and Ambiguity in Virtual Worlds

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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.

Vignettes of Ambiguity

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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…

Properties of Ambiguity Functions

OpenAIRE

Mulcahy-Stanislawczyk, John

2014-01-01

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

Lexical ambiguity resolution

Energy Technology Data Exchange (ETDEWEB)

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

1987-01-01

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

DIFFERENCES OF THE ROLE AMBIGUITY IN OFFENSE RESPONSIBILITIES OF TEAM SPORTS

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Karamousalidis, G.

2009-10-01

Full Text Available The purpose of this research was to investigate the differences of the role ambiguity in offense responsibilitiesfor athletes of team sports. As sample were used 421 athletes of basketball (n=125, handball (n=106, volleyball(n=78 and soccer (n=112. We used the role ambiguity questionnaire (Role Ambiguity Scale, Beauchamp et al.,2002 and referred to the athletes’ responsibilities in offense.The correlations of items were high and ranged from .57 to .75, p <.01 whereas from the one way analysis (oneway, Anova appeared some statistically serious differences in one factor of role ambiguity (ambiguity inrelation to the scope of responsibilities in offense, F (3,415 = 4,416, p <.005. The volleyball and the handballathletes had more well defined roles regardless the scope of their responsibilities in offense, in relation to thoseof soccer. On the whole we come to the conclusion that among team sports there are not any differences in roleambiguity in offense responsibilities, except in one factor. More researches are necessary in connection to othervariables.

Neural Mechanisms Underlying Risk and Ambiguity Attitudes.

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

2017-11-01

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

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

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

2002-01-01

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

FrFT-CSWSF: Estimating cross-range velocities of ground moving targets using multistatic synthetic aperture radar

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Li Chenlei

2014-10-01

Full Text Available Estimating cross-range velocity is a challenging task for space-borne synthetic aperture radar (SAR, which is important for ground moving target indication (GMTI. Because the velocity of a target is very small compared with that of the satellite, it is difficult to correctly estimate it using a conventional monostatic platform algorithm. To overcome this problem, a novel method employing multistatic SAR is presented in this letter. The proposed hybrid method, which is based on an extended space-time model (ESTIM of the azimuth signal, has two steps: first, a set of finite impulse response (FIR filter banks based on a fractional Fourier transform (FrFT is used to separate multiple targets within a range gate; second, a cross-correlation spectrum weighted subspace fitting (CSWSF algorithm is applied to each of the separated signals in order to estimate their respective parameters. As verified through computer simulation with the constellations of Cartwheel, Pendulum and Helix, this proposed time-frequency-subspace method effectively improves the estimation precision of the cross-range velocities of multiple targets.

unique determination of structure and velocity by 3-d tomographic ...

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In this paper the cause of this velocity-depth ambiguity is examined and a methodology is proposed that ..... Thus the matrix. A has a null space and we have infinite solution ... acquired in the North Sea along 10 parallel profiles with a ship ...

Sampling experience reverses preferences for ambiguity

NARCIS (Netherlands)

Ert, E.; Trautmann, S.T.

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

Ambiguity: A new way of thinking about responses to climate change.

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Fleming, A; Howden, S M

2016-11-15

Diversity, interdisciplinarity and transdisciplinarity are now recognized as vital to tackling wicked problems such as those presented by a changing climate (Nature editorial 2015, Ledford 2015; Dick et al., 2016). Including diverse disciplines in science projects enables a range of different views which often facilitate the creation of innovative solutions. Supporting multiple views and options requires a different way of working beyond traditional reductionist approaches to science, communication and decision-making. To embrace diversity in scientific project teams in order to tackle complex, integrated and urgent issues but to expect singular and linear pathways forward is paradoxical. Much has been written about the need for the scientific community to embrace uncertainty (e.g. Popper, Lempert & Bankes 2005; Lempert et al., 2004; Nelson, Howden & Hayman 2013; Bammer & Smithson 2008). We argue that this in itself will not suffice, and that there is also a need to embrace ambiguity in certain situations. Thus, in this article we explore: (1) what ambiguity is, including the benefits it can offer to climate adaptation in particular, using existing approaches to ambiguity in the arts and humanities as examples (2), we discuss practical meanings of ambiguity in relation to climate change, (3) we propose possible next steps for bringing ambiguity into interdisciplinary practice, and (4) we identify some challenges and necessary preconditions to successfully and appropriately embracing ambiguity. Copyright © 2016 Elsevier B.V. All rights reserved.

On the impact of GNSS ambiguity resolution: geometry, ionosphere, time and biases

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

2018-06-01

Integer ambiguity resolution (IAR) is the key to fast and precise GNSS positioning and navigation. Next to the positioning parameters, however, there are several other types of GNSS parameters that are of importance for a range of different applications like atmospheric sounding, instrumental calibrations or time transfer. As some of these parameters may still require pseudo-range data for their estimation, their response to IAR may differ significantly. To infer the impact of ambiguity resolution on the parameters, we show how the ambiguity-resolved double-differenced phase data propagate into the GNSS parameter solutions. For that purpose, we introduce a canonical decomposition of the GNSS network model that, through its decoupled and decorrelated nature, provides direct insight into which parameters, or functions thereof, gain from IAR and which do not. Next to this qualitative analysis, we present for the GNSS estimable parameters of geometry, ionosphere, timing and instrumental biases closed-form expressions of their IAR precision gains together with supporting numerical examples.

Ambiguity effects of rhyme and meter.

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Wallot, Sebastian; Menninghaus, Winfried

2018-04-23

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

GPS Based Reduced-Dynamic Orbit Determination for Low Earth Orbiters with Ambiguity Fixing

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Yang Yang

2015-01-01

Full Text Available With the ever-increasing number of satellites in Low Earth Orbit (LEO for scientific missions, the precise determination of the position and velocity of the satellite is a necessity. GPS (Global Positioning System based reduced-dynamic orbit determination (RPOD method is commonly used in the post processing with high precision. This paper presents a sequential RPOD strategy for LEO satellite in the framework of Extended Kalman Filter (EKF. Precise Point Positioning (PPP technique is used to process the GPS observations, with carrier phase ambiguity resolution using Integer Phase Clocks (IPCs products. A set of GRACE (Gravity Recovery And Climate Experiment mission data is used to test and validate the RPOD performance. Results indicate that orbit determination accuracy could be improved by 15% in terms of 3D RMS error in comparison with traditional RPOD method with float ambiguity solutions.

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

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

2017-10-01

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

A Neural Signature Encoding Decisions under Perceptual Ambiguity.

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Sun, Sai; Yu, Rongjun; Wang, Shuo

2017-01-01

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

Analyzing Ambiguity of Context-Free Grammars

DEFF Research Database (Denmark)

Brabrand, Claus; Giegerich, Robert; Møller, Anders

2010-01-01

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

Climate change velocity since the Last Glacial Maximum and its importance for patterns of species richness and range size

DEFF Research Database (Denmark)

Sandel, Brody Steven; Arge, Lars Allan; Svenning, J.-C.

to fully occupy suitable habitat, or when local diversification rates are depressed by local population extinctions and changing selective regimes. Locations with long-term climate instability should therefore show reduced species richness with small-ranged species particularly missing from the community...... these predictions using global data on mammal and amphibian distributions. Consistent with our predictions, richness of small-ranged species of both groups was negatively associated with velocity. Velocity generally explained more variation in richness than did the simple climate anomaly. Climate velocity appears...... to capture an important historical signal on current mammal and amphibian distributions....

Generative Learning: Adults Learning within Ambiguity

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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…

Positive fEMG Patterns with Ambiguity in Paintings.

Science.gov (United States)

Jakesch, Martina; Goller, Juergen; Leder, Helmut

2017-01-01

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

Blue Creek Winter Range: Wildlife Mitigation Project

International Nuclear Information System (INIS)

1994-01-01

This preliminary Environmental Assessment examines the potential environmental effects of securing land and conducting wildlife habitat enhancement and long term management activities within the boundaries of the Spokane Indian Reservation. Four proposed activities are analyzed: Habitat protection; Habitat enhancement; Operation and maintenance; and Monitoring and evaluation. The proposed action is intended to meet the need for mitigation of wildlife and wildlife habitat adversely affected by the construction of Grand Coulee Dam and its reservoir

Ambiguity resolving based on cosine property of phase differences for 3D source localization with uniform circular array

Science.gov (United States)

Chen, Xin; Wang, Shuhong; Liu, Zhen; Wei, Xizhang

2017-07-01

Localization of a source whose half-wavelength is smaller than the array aperture would suffer from serious phase ambiguity problem, which also appears in recently proposed phase-based algorithms. In this paper, by using the centro-symmetry of fixed uniform circular array (UCA) with even number of sensors, the source's angles and range can be decoupled and a novel ambiguity resolving approach is addressed for phase-based algorithms of source's 3-D localization (azimuth angle, elevation angle, and range). In the proposed method, by using the cosine property of unambiguous phase differences, ambiguity searching and actual-value matching are first employed to obtain actual phase differences and corresponding source's angles. Then, the unambiguous angles are utilized to estimate the source's range based on a one dimension multiple signal classification (1-D MUSIC) estimator. Finally, simulation experiments investigate the influence of step size in search and SNR on performance of ambiguity resolution and demonstrate the satisfactory estimation performance of the proposed method.

Inherent ambiguities in the determination of phase-shifts

International Nuclear Information System (INIS)

Atkinson, D.

1975-01-01

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

Probability judgments under ambiguity and conflict.

Science.gov (United States)

Smithson, Michael

2015-01-01

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

Renormalon ambiguities in NRQCD operator matrix elements

International Nuclear Information System (INIS)

Bodwin, G.T.; Chen, Y.

1999-01-01

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

Neural Correlates of Decision-Making Under Ambiguity and Conflict.

Science.gov (United States)

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

2015-01-01

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

Reactive agents and perceptual ambiguity

NARCIS (Netherlands)

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

2005-01-01

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

Alcohol reduces aversion to ambiguity

Directory of Open Access Journals (Sweden)

Tadeusz eTyszka

2015-01-01

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

Alcohol reduces aversion to ambiguity.

Science.gov (United States)

Tyszka, Tadeusz; Macko, Anna; Stańczak, Maciej

2014-01-01

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

Estimation of a melting probe's penetration velocity range to reach icy moons' subsurface ocean

Science.gov (United States)

Erokhina, Olga; Chumachenko, Eugene

2014-05-01

In modern space science one of the actual branches is icy satellites explorations. The main interest is concentrated around Jovian's moons Europa and Ganymede, Saturn's moons Titan and Enceladus that are covered by thick icy layer according to "Voyager1", "Voyager2", "Galileo" and "Cassini" missions. There is a big possibility that under icy shell could be a deep ocean. Also conditions on these satellites allow speculating about possible habitability, and considering these moons from an astrobiological point of view. One of the possible tasks of planned missions is a subsurface study. For this goal it is necessary to design special equipment that could be suitable for planetary application. One of the possible means is to use a melting probe which operates by melting and moves by gravitational force. Such a probe should be relatively small, should not weight too much and should require not too much energy. In terrestrial case such kind of probe has been successfully used for glaciers study. And it is possible to extrapolate the usage of such probe to extraterrestrial application. One of the tasks is to estimate melting probe's penetration velocity. Although there are other unsolved problems such as analyzing how the probe will move in low gravity and low atmospheric pressure; knowing whether hole will be closed or not when probe penetrate thick enough; and considering what order could be a penetration velocity. This study explores two techniques of melting probe's movement. One of them based on elasto-plastic theory and so-called "solid water" theory, and other one takes phase changing into account. These two techniques allow estimating melting probe's velocity range and study whole process. Based on these technique several cases of melting probe movement were considered, melting probe's velocity range estimated, influence of different factors studied and discussed and an easy way to optimize parameters of the melting probe proposed.

Frequency Diverse Array Radar Cramér-Rao Lower Bounds for Estimating Direction, Range, and Velocity

Directory of Open Access Journals (Sweden)

Yongbing Wang

2014-01-01

Full Text Available Different from phased-array radar, frequency diverse array (FDA radar offers range-dependent beampattern and thus provides new application potentials. But there is a fundamental question: what estimation performance can achieve for an FDA radar? In this paper, we derive FDA radar Cramér-Rao lower bounds (CRLBs for estimating direction, range (time delay, and velocity (Doppler shift. Two different data models including pre- and postmatched filtering are investigated separately. As the FDA radar has range-angle coupling, we use a simple transmit subaperturing strategy which divides the whole array into two subarrays, each uses a distinct frequency increment. Assuming temporally white Gaussian noise and linear frequency modulated transmit signal, extensive simulation examples are performed. When compared to conventional phased-array radar, FDA can yield better CRLBs for estimating the direction, range, and velocity. Moreover, the impacts of the element number and frequency increment are also analyzed. Simulation results show that the CRLBs decrease with the increase of the elements number and frequency increment.

Risk, Ambiguity, and Insurance.

Science.gov (United States)

1984-10-01

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

Measurements and correlations of turbulent burning velocities over wide ranges of fuels and elevated pressures

KAUST Repository

Bradley, Derek; Lawes, Malcolm; Liu, Kexin; Mansour, Morkous S.

2013-01-01

The implosion technique has been used to extend measurements of turbulent burning velocities over greater ranges of fuels and pressures. Measurements have been made up to 3.5 MPa and at strain rate Markstein numbers as low as 23. The implosion technique, with spark ignition at two opposite wall positions within a fan-stirred spherical bomb is capable of measuring turbulent burning velocities, at higher pressures than is possible with central ignition. Pressure records and schlieren high speed photography define the rate of burning and the smoothed area of the flame front. The first aim of the study was to extend the previous measurements with ethanol and propane-air, with further measurements over wider ranges of fuels and equivalence ratios with mixtures of hydrogen, methane, 10% hydrogen-90% methane, toluene, and i-octane, with air. The second aim was to study further the low turbulence regime in which turbulent burning co-exists with laminar flame instabilities. Correlations are presented of turbulent burning velocity normalised by the effective rms turbulent velocity acting on the flame front, ut=u0k , with the Karlovitz stretch factor, K, for different strain rate Markstein numbers, a decrease in which increases ut=u0k . Experimental correlations are presented for the present measurements, combined with previous ones. Different burning regimes are also identified, extending from that of mixed turbulence/laminar instability at low values of K to that at high values of K, in which ut=u0k is gradually reduced due to increasing localised flame extinctions. © 2012 The Combustion Institute.

Recommendations for reducing ambiguity in written procedures.

Energy Technology Data Exchange (ETDEWEB)

Matzen, Laura E.

2009-11-01

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

The Ethics of Strategic Ambiguity.

Science.gov (United States)

Paul, Jim; Strbiak, Christy A.

1997-01-01

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

Measurement bias of fluid velocity in molecular simulations

International Nuclear Information System (INIS)

Tysanner, Martin W.; Garcia, Alejandro L.

2004-01-01

In molecular simulations of fluid flow, the measurement of mean fluid velocity is considered to be a straightforward computation, yet there is some ambiguity in its definition. We show that in systems far from equilibrium, such as those with large temperature or velocity gradients, two commonly used definitions give slightly different results. Specifically, a bias can arise when computing the mean fluid velocity by measuring the mean particle velocity in a cell and averaging this mean over samples. We show that this bias comes from the correlation of momentum and density fluctuations in non-equilibrium fluids, obtain an analytical expression for predicting it, and discuss what system characteristics (e.g., number of particles per cell, temperature gradients) reduce or magnify the error. The bias has a physical origin so although we demonstrate it by direct simulation Monte Carlo (DSMC) computations, the same effect will be observed with other particle-based simulation methods, such as molecular dynamics and lattice gases

Quantization ambiguity, ergodicity and semiclassics

International Nuclear Information System (INIS)

Kaplan, Lev

2002-01-01

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

Semi-classical analysis of optical model ambiguities

International Nuclear Information System (INIS)

Cuer, M.

1979-01-01

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

Ambiguous walls

DEFF Research Database (Denmark)

Mody, Astrid

2012-01-01

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

Gauge-fixing ambiguity and monopole number

International Nuclear Information System (INIS)

Hioki, S.; Miyamura, O.

1991-01-01

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

Ambiguous Adaptation

DEFF Research Database (Denmark)

Møller Larsen, Marcus; Lyngsie, Jacob

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

Eliminating ambiguity in digital signals

Science.gov (United States)

Weber, W. J., III

1979-01-01

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

The First Result of Relative Positioning and Velocity Estimation Based on CAPS

Science.gov (United States)

Zhao, Jiaojiao; Ge, Jian; Wang, Liang; Wang, Ningbo; Zhou, Kai; Yuan, Hong

2018-01-01

The Chinese Area Positioning System (CAPS) is a new positioning system developed by the Chinese Academy of Sciences based on the communication satellites in geosynchronous orbit. The CAPS has been regarded as a pilot system to test the new technology for the design, construction and update of the BeiDou Navigation Satellite System (BDS). The system structure of CAPS, including the space, ground control station and user segments, is almost like the traditional Global Navigation Satellite Systems (GNSSs), but with the clock on the ground, the navigation signal in C waveband, and different principles of operation. The major difference is that the CAPS navigation signal is first generated at the ground control station, before being transmitted to the satellite in orbit and finally forwarded by the communication satellite transponder to the user. This design moves the clock from the satellite in orbit to the ground. The clock error can therefore be easily controlled and mitigated to improve the positioning accuracy. This paper will present the performance of CAPS-based relative positioning and velocity estimation as assessed in Beijing, China. The numerical results show that, (1) the accuracies of relative positioning, using only code measurements, are 1.25 and 1.8 m in the horizontal and vertical components, respectively; (2) meanwhile, they are about 2.83 and 3.15 cm in static mode and 6.31 and 10.78 cm in kinematic mode, respectively, when using the carrier-phase measurements with ambiguities fixed; and (3) the accuracy of the velocity estimation is about 0.04 and 0.11 m/s in static and kinematic modes, respectively. These results indicate the potential application of CAPS for high-precision positioning and velocity estimation and the availability of a new navigation mode based on communication satellites. PMID:29757204

Productive Ambiguity in the Learning of Mathematics

Science.gov (United States)

Foster, Colin

2011-01-01

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

An appraisal of river erosion mitigation in the Niger Delta

International Nuclear Information System (INIS)

Aban, T. K. S.; Omuso, W. O.

1999-01-01

River erosion processes in the Niger Delta and the effectiveness of locally applied remedial measures is appraised, using information on channel geometry, flow velocity distribution, soil type, stratification, bank height and steepness, state of compaction, together with pool level variation in river channels. High flow velocity and bank height were identified as the major erosion causative factors. Local responses towards erosion mitigation have involved structural methods to varying degree of success. River training has been recommended as a long - term regional approach to mitigate river bank erosion. However, in the short -term revetments, concrete and sheets piles may be applied cautiously

Superconducting RF for Low-Velocity and Intermediate-Velocity Beams

CERN Document Server

Grimm, Terry L

2005-01-01

Existing superconducting radio frequency (SRF) linacs are used to accelerate ions (protons through uranium) with velocities less than about 15% the speed of light, or electrons with velocities approximately equal to the speed of light. In the last ten years, prototype SRF cavities have completely covered the remaining range of velocities. They have demonstrated that SRF linacs will be capable of accelerating electrons from rest up to the speed of light, and ions from less than 1% up to the speed of light. When the Spallation Neutron Source is operational, SRF ion linacs will have covered the full range of velocities except for v/c ~ 0.15 to v/c ~ 0.5. A number of proposed projects (RIA, EURISOL) would span the latter range of velocities. Future SRF developments will have to address the trade-offs associated with a number of issues, including high gradient operation, longitudinal and transverse acceptance, microphonics, Lorentz detuning, operating temperature, cryogenic load, number of gaps or cells per cavity...

Ambiguous Intimacy

DEFF Research Database (Denmark)

Houmøller, Kathrin

2015-01-01

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

Analyzing Ambiguity of Context-Free Grammars

DEFF Research Database (Denmark)

Brabrand, Claus; Giegerich, Robert; Møller, Anders

2007-01-01

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

Perturbative ambiguities in Coulomb gauge QCD

International Nuclear Information System (INIS)

Doust, P.

1987-01-01

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

The effect of electron range on electron beam induced current collection and a simple method to extract an electron range for any generation function

International Nuclear Information System (INIS)

Lahreche, A.; Beggah, Y.; Corkish, R.

2011-01-01

The effect of electron range on electron beam induced current (EBIC) is demonstrated and the problem of the choice of the optimal electron ranges to use with simple uniform and point generation function models is resolved by proposing a method to extract an electron range-energy relationship (ERER). The results show that the use of these extracted electron ranges remove the previous disagreement between the EBIC curves computed with simple forms of generation model and those based on a more realistic generation model. The impact of these extracted electron ranges on the extraction of diffusion length, surface recombination velocity and EBIC contrast of defects is discussed. It is also demonstrated that, for the case of uniform generation, the computed EBIC current is independent of the assumed shape of the generation volume. -- Highlights: → Effect of electron ranges on modeling electron beam induced current is shown. → A method to extract an electron range for simple form of generation is proposed. → For uniform generation the EBIC current is independent of the choice of it shape. → Uses of the extracted electron ranges remove some existing literature ambiguity.

Ambiguous Genitalia

Science.gov (United States)

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

Ambiguity and Volatility : Asset Pricing Implications

NARCIS (Netherlands)

Pataracchia, B.

2011-01-01

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

Ambiguity attitudes in decisions for others

NARCIS (Netherlands)

König-Kersting, Christian; Trautmann, Stefan

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

The skew ray ambiguity in the analysis of videokeratoscopic data.

Science.gov (United States)

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

2007-05-01

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

Gene name ambiguity of eukaryotic nomenclatures.

Science.gov (United States)

Chen, Lifeng; Liu, Hongfang; Friedman, Carol

2005-01-15

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

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

Science.gov (United States)

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

2016-01-01

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

Does ambiguity aversion survive in experimental asset markets?

NARCIS (Netherlands)

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

2014-01-01

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

Ambiguities and conventions in the perception of visual art.

Science.gov (United States)

Mamassian, Pascal

2008-09-01

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

Equity Trading under Heterogeneity in Ambiguity

DEFF Research Database (Denmark)

Alonso, Irasema; Prado, Mauricio

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

Precise Point Positioning with Partial Ambiguity Fixing.

Science.gov (United States)

Li, Pan; Zhang, Xiaohong

2015-06-10

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

Semantic Ambiguity Effects in L2 Word Recognition.

Science.gov (United States)

Ishida, Tomomi

2018-06-01

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

Processing subject-object ambiguities in Dutch

NARCIS (Netherlands)

Kaan, Edith

1997-01-01

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

SAR Ambiguity Study for the Cassini Radar

Science.gov (United States)

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

1993-01-01

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

Regularization ambiguities in loop quantum gravity

International Nuclear Information System (INIS)

Perez, Alejandro

2006-01-01

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

Ambiguity and violence in adolescent dating relationships.

Science.gov (United States)

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

2012-08-01

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

Potential Ambiguity Translation Performances within Legal Language Institutional Nomenclature

Directory of Open Access Journals (Sweden)

Oţăt Diana

2015-12-01

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

Combined GPS/GLONASS Precise Point Positioning with Fixed GPS Ambiguities

Science.gov (United States)

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

2014-01-01

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

Combined GPS/GLONASS Precise Point Positioning with Fixed GPS Ambiguities

Directory of Open Access Journals (Sweden)

Lin Pan

2014-09-01

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

Concept analysis: Role ambiguity in senior nursing students.

Science.gov (United States)

Kalkman, Beth

2018-04-01

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

Ambiguous science and the visual representation of the real

Science.gov (United States)

Newbold, Curtis Robert

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

Precise orbit determination of the Sentinel-3A altimetry satellite using ambiguity-fixed GPS carrier phase observations

Science.gov (United States)

Montenbruck, Oliver; Hackel, Stefan; Jäggi, Adrian

2017-11-01

The Sentinel-3 mission takes routine measurements of sea surface heights and depends crucially on accurate and precise knowledge of the spacecraft. Orbit determination with a targeted uncertainty of less than 2 cm in radial direction is supported through an onboard Global Positioning System (GPS) receiver, a Doppler Orbitography and Radiopositioning Integrated by Satellite instrument, and a complementary laser retroreflector for satellite laser ranging. Within this study, the potential of ambiguity fixing for GPS-only precise orbit determination (POD) of the Sentinel-3 spacecraft is assessed. A refined strategy for carrier phase generation out of low-level measurements is employed to cope with half-cycle ambiguities in the tracking of the Sentinel-3 GPS receiver that have so far inhibited ambiguity-fixed POD solutions. Rather than explicitly fixing double-difference phase ambiguities with respect to a network of terrestrial reference stations, a single-receiver ambiguity resolution concept is employed that builds on dedicated GPS orbit, clock, and wide-lane bias products provided by the CNES/CLS (Centre National d'Études Spatiales/Collecte Localisation Satellites) analysis center of the International GNSS Service. Compared to float ambiguity solutions, a notably improved precision can be inferred from laser ranging residuals. These decrease from roughly 9 mm down to 5 mm standard deviation for high-grade stations on average over low and high elevations. Furthermore, the ambiguity-fixed orbits offer a substantially improved cross-track accuracy and help to identify lateral offsets in the GPS antenna or center-of-mass (CoM) location. With respect to altimetry, the improved orbit precision also benefits the global consistency of sea surface measurements. However, modeling of the absolute height continues to rely on proper dynamical models for the spacecraft motion as well as ground calibrations for the relative position of the altimeter reference point and the CoM.

Clarity and ambiguity in strategic corporate communication

DEFF Research Database (Denmark)

Gulbrandsen, Ib Tunby

2017-01-01

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

Clarity and ambiguity in strategic corporate communication

DEFF Research Database (Denmark)

Gulbrandsen, Ib Tunby

2018-01-01

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

Risk Management and Insurance Decisions under Ambiguity

DEFF Research Database (Denmark)

Martínez-Correa, Jimmy

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

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

Science.gov (United States)

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

2016-01-01

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

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

Directory of Open Access Journals (Sweden)

Jordi Grau-Moya

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

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

Science.gov (United States)

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

2016-01-01

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

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

Science.gov (United States)

Paul, Jim; And Others

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

Gas powered fluid gun with recoil mitigation

Science.gov (United States)

Grubelich, Mark C; Yonas, Gerold

2013-11-12

A gas powered fluid gun for propelling a stream or slug of a fluid at high velocity toward a target. Recoil mitigation is provided that reduces or eliminates the associated recoil forces, with minimal or no backwash. By launching a quantity of water in the opposite direction, net momentum forces are reduced or eliminated. Examples of recoil mitigation devices include a cone for making a conical fluid sheet, a device forming multiple impinging streams of fluid, a cavitating venturi, one or more spinning vanes, or an annular tangential entry/exit.

Global optimization applied to GPS positioning by ambiguity functions

International Nuclear Information System (INIS)

Baselga, Sergio

2010-01-01

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

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

Science.gov (United States)

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

2017-05-17

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

Pricing risk and ambiguity: the effect of perspective taking.

Science.gov (United States)

Trautmann, Stefan T; Schmidt, Ulrich

2012-01-01

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

Ambiguity aversion and household portfolio choice puzzles: Empirical evidence*

Science.gov (United States)

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

2017-01-01

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

Ambiguity aversion and household portfolio choice puzzles: Empirical evidence.

Science.gov (United States)

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

2016-03-01

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

Hellsgate Winter Range Mitigation Project; Long-term Management Plan, Project Report 1993, Final Draft.

Energy Technology Data Exchange (ETDEWEB)

Berger, Matthew T.

1994-01-01

A study was conducted on the Hellsgate Winter Range Mitigation Project area, a 4,943 acre ranch purchased for mitigating some habitat losses associated with the original construction of Grand Coulee Dam and innundation of habitat by Lake Roosevelt. A Habitat Evaluation Procedure (HEP) study was used to determine habitat quality and quantity baseline data and future projections. Target species used in the study were sharp-tailed grouse (Tympanuchus phasianellus), mule deer (Odocoileus hemoinus), mink (Mustela vison), spotted sandpiper (Actiius colchicus), bobcat (Felis reufs), blue grouse (Dendragapus obscurus), and mourning dove (Zenaida macroura). From field data collected, limiting life values or HSI's (Habitat Suitability Index's) for each indicator species was determined for existing habitats on project lands. From this data a long term management plan was developed. This report is designed to provide guidance for the management of project lands in relation to the habitat cover types discussed and the indicator species used to evaluate these cover types. In addition, the plan discusses management actions, habitat enhancements, and tools that will be used to enhance, protect and restore habitats to desired conditions. Through planned management actions biodiversity and vegetative structure can be optimized over time to reduce or eliminate, limiting HSI values for selected wildlife on project lands.

Stress wave propagation and mitigation in two polymeric foams

Science.gov (United States)

Pradel, Pierre; Malaise, Frederic; Cadilhon, Baptiste; Quessada, Jean-Hugues; de Resseguier, Thibaut; Delhomme, Catherine; Le Blanc, Gael

2017-06-01

Polymeric foams are widely used in industry for thermal insulation or shock mitigation. This paper investigates the ability of a syntactic epoxy foam and an expanded polyurethane foam to mitigate intense (several GPa) and short duration (<10-6 s) stress pulses. Plate impact and electron beam irradiation experiments have been conducted to study the dynamic mechanical responses of both foams. Interferometer Doppler Laser method is used to record the target rear surface velocity. A two-wave structure associated with the propagation of an elastic precursor followed by the compaction of the pores has been observed. The compaction stress level deduced from the velocity measurement is a good indicator of mitigation capability of the foams. Quasi-static tests and dynamic soft recovery experiments have also been performed to determine the compaction mechanisms. In the polyurethane foam, the pores are closed by elastic buckling of the matrix and damage of the structure. In the epoxy foam, the compaction is due to the crushing of glass microspheres. Two porous material models successfully represent the macroscopic response of these polymeric foams.

Portfolio Management with Stochastic Interest Rates and Inflation Ambiguity

DEFF Research Database (Denmark)

Munk, Claus; Rubtsov, Alexey Vladimirovich

2014-01-01

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

ANALYSIS OF DESIGN RANGE FOR A STROKING SEAT ON A STROKING FLOOR TO MITIGATE BLAST LOADING EFFECTS

Science.gov (United States)

2017-05-16

addition, due to the extreme range in the mobility and other operational requirements in the battlefield, there is also a need even for light tactical...Government or the DoA, and shall not be used for advertising or product endorsement purposes. REFERENCES [1] Bird, S., and Fairweather. C., "Recent...UNCLASSIFIED LIST OF SYMBOLS, ABBREVIATIONS, ACRONYMS ATD Anthropomorphic Test Device , or Dummy CAMEL Concept for Advanced Military Explosion-mitigating

Discrete ambiguities in CP-violating asymmetries in B decays

International Nuclear Information System (INIS)

London, David

1998-01-01

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

An ambiguity in fermionic string perturbation theory

International Nuclear Information System (INIS)

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

1988-01-01

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

Characteristics of a pure-state ambiguity function

International Nuclear Information System (INIS)

Praxmeyer, Ludmila; Vitanov, Nikolay; Stenholm, Stig

2009-01-01

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

Comparing Tolerance of Ambiguity in Veterinary and Medical Students.

Science.gov (United States)

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

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

Ambiguous Adaptation

DEFF Research Database (Denmark)

Møller Larsen, Marcus; Lyngsie, Jacob

2017-01-01

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

Crichton ambiguities with infinitely many partial waves

NARCIS (Netherlands)

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

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

Ambiguity, Ambivalence and Extravagance in The Hunger Games

OpenAIRE

Oliver, Kelly

2014-01-01

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

Children do not exhibit ambiguity aversion despite intact familiarity bias.

Science.gov (United States)

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

2014-01-01

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

Constraints and Ambiguity

DEFF Research Database (Denmark)

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

2017-01-01

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

Does ambiguity aversion influence the framing effect during decision making?

Science.gov (United States)

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

2015-04-01

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

Measuring Ambiguity in HLA Typing Methods

Science.gov (United States)

Madbouly, Abeer; Freeman, John; Maiers, Martin

2012-01-01

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

Measuring ambiguity in HLA typing methods.

Directory of Open Access Journals (Sweden)

Vanja Paunić

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

Resolving fringe ambiguities of a wide-field Michelson interferometer using visibility measurements of a noncollimated laser beam.

Science.gov (United States)

Wan, Xiaoke; Wang, Ji; Ge, Jian

2009-09-10

An actively stabilized interferometer with a constant optical path difference is a key element in long-term astronomical observation, and resolving interference fringe ambiguities is important to produce high-precision results for the long term. We report a simple and reliable method of resolving fringe ambiguities of a wide-field Michelson interferometer by measuring the interference visibility of a noncollimated single-frequency laser beam. Theoretical analysis shows that the interference visibility is sensitive to a subfringe phase shift, and a wide range of beam arrangements is suitable for real implementation. In an experimental demonstration, a Michelson interferometer has an optical path difference of 7 mm and a converging monitoring beam has a numerical aperture of 0.045 with an incidental angle of 17 degrees. The resolution of visibility measurements corresponds to approximately 1/16 fringe in the interferometer phase shift. The fringe ambiguity-free region is extended over a range of approximately 100 fringes.

Individual differences in aversion to ambiguity regarding medical tests and treatments: association with cancer screening cognitions.

Science.gov (United States)

Han, Paul K J; Williams, Andrew E; Haskins, Amy; Gutheil, Caitlin; Lucas, F Lee; Klein, William M P; Mazor, Kathleen M

2014-12-01

Aversion to "ambiguity"-uncertainty about the reliability, credibility, or adequacy of information-about medical tests and treatments is an important psychological response that varies among individuals, but little is known about its nature and extent. The purpose of this study was to examine how individual-level ambiguity aversion relates to important health cognitions related to different cancer screening tests. A survey of 1,074 adults, ages 40 to 70 years, was conducted in four integrated U.S. healthcare systems. The Ambiguity Aversion in Medicine (AA-Med) scale, a measure of individual differences in aversion to ambiguity (AA) about medical tests and treatments, was administered along with measures of several cancer screening-related cognitions: perceived benefits and harms of colonoscopy, mammography, and PSA screening, and ambivalence and future intentions regarding these tests. Multivariable analyses were conducted to assess the associations between AA-Med scores and cancer screening cognitions. Individual-level AA as assessed by the AA-Med scale was significantly associated (P ambiguity. Individual-level AA constitutes a measurable, wide-ranging cognitive bias against medical intervention, and more research is needed to elucidate its mechanisms and effects. ©2014 American Association for Cancer Research.

Triple-frequency GPS precise point positioning with rapid ambiguity resolution

Science.gov (United States)

Geng, Jianghui; Bock, Yehuda

2013-05-01

At present, reliable ambiguity resolution in real-time GPS precise point positioning (PPP) can only be achieved after an initial observation period of a few tens of minutes. In this study, we propose a method where the incoming triple-frequency GPS signals are exploited to enable rapid convergences to ambiguity-fixed solutions in real-time PPP. Specifically, extra-wide-lane ambiguity resolution can be first achieved almost instantaneously with the Melbourne-Wübbena combination observable on L2 and L5. Then the resultant unambiguous extra-wide-lane carrier-phase is combined with the wide-lane carrier-phase on L1 and L2 to form an ionosphere-free observable with a wavelength of about 3.4 m. Although the noise of this observable is around 100 times the raw carrier-phase noise, its wide-lane ambiguity can still be resolved very efficiently, and the resultant ambiguity-fixed observable can assist much better than pseudorange in speeding up succeeding narrow-lane ambiguity resolution. To validate this method, we use an advanced hardware simulator to generate triple-frequency signals and a high-grade receiver to collect 1-Hz data. When the carrier-phase precisions on L1, L2 and L5 are as poor as 1.5, 6.3 and 1.5 mm, respectively, wide-lane ambiguity resolution can still reach a correctness rate of over 99 % within 20 s. As a result, the correctness rate of narrow-lane ambiguity resolution achieves 99 % within 65 s, in contrast to only 64 % within 150 s in dual-frequency PPP. In addition, we also simulate a multipath-contaminated data set and introduce new ambiguities for all satellites every 120 s. We find that when multipath effects are strong, ambiguity-fixed solutions are achieved at 78 % of all epochs in triple-frequency PPP whilst almost no ambiguities are resolved in dual-frequency PPP. Therefore, we demonstrate that triple-frequency PPP has the potential to achieve ambiguity-fixed solutions within a few minutes, or even shorter if raw carrier-phase precisions are

Experimental investigation of blast mitigation and particle-blast interaction during the explosive dispersal of particles and liquids

Science.gov (United States)

Pontalier, Q.; Loiseau, J.; Goroshin, S.; Frost, D. L.

2018-05-01

The attenuation of a blast wave from a high-explosive charge surrounded by a layer of inert material is investigated experimentally in a spherical geometry for a wide range of materials. The blast wave pressure is inferred from extracting the blast wave velocity with high-speed video as well as direct measurements with pressure transducers. The mitigant consists of either a packed bed of particles, a particle bed saturated with water, or a homogeneous liquid. The reduction in peak blast wave overpressure is primarily dependent on the mitigant to explosive mass ratio, M/ C, with the mitigant material properties playing a secondary role. Relative peak pressure mitigation reduces with distance and for low values of M/ C (compaction, deformation, and fracture of the powders plays an important role. The difference in scaled arrival time of the blast and material fronts increases with M/ C and scaled distance, with solid particles giving the largest separation between the blast wave and cloud of particles. Surrounding a high-explosive charge with a layer of particles reduces the positive-phase blast impulse, whereas a liquid layer has no influence on the impulse in the far field. Taking the total impulse due to the blast wave and material impact into account implies that the damage to a nearby structure may actually be augmented for a range of distances. These results should be taken into consideration in the design of explosive mitigant systems.

Isoclinic Ambiguity Unwrapping of Circular Ring under Diametric Compression

Directory of Open Access Journals (Sweden)

Huang M.-J.

2010-06-01

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

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

Science.gov (United States)

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

2015-12-01

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

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

Science.gov (United States)

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

2016-01-01

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

The dark side of ambiguous discrimination: how state self-esteem moderates emotional and behavioural responses to ambiguous and unambiguous discrimination.

Science.gov (United States)

Cihangir, Sezgin; Barreto, Manuela; Ellemers, Naomi

2010-03-01

Two experiments examine how experimentally induced differences in state self-esteem moderate emotional and behavioural responses to ambiguous and unambiguous discrimination. Study 1 (N=108) showed that participants who were exposed to ambiguous discrimination report more negative self-directed emotions when they have low compared to high self-esteem. These differences did not emerge when participants were exposed to unambiguous discrimination. Study 2 (N=118) additionally revealed that self-esteem moderated the effect of ambiguous discrimination on self-concern, task performance, and self-stereotyping. Results show that ambiguous discrimination caused participants with low self-esteem to report more negative self-directed emotions, more self-concern, an inferior task performance, and more self-stereotyping, compared to participants in the high self-esteem condition. Emotional and behavioural responses to unambiguous discrimination did not depend on the induced level of self-esteem in these studies.

Crichton ambiguities with infinitely many partial waves

International Nuclear Information System (INIS)

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

1978-01-01

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

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

International Nuclear Information System (INIS)

Forest, T. de Jr.

1984-01-01

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

Hemispheric Asymmetries in Semantic Processing: Evidence from False Memories for Ambiguous Words

Science.gov (United States)

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

2008-01-01

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,…

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

International Nuclear Information System (INIS)

Kelly, J.J.

1997-01-01

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

There is a continuum ambiguity for elastic πN amplitudes

International Nuclear Information System (INIS)

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

1984-01-01

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

The Communicative Function of Ambiguity in Language

Science.gov (United States)

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

2012-01-01

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

The Fuzzy Front End of Experience Design – Considering Ambiguous and Prescribed Qualities

DEFF Research Database (Denmark)

Ghellal, Sabiha

2015-01-01

. Focusing on the phenomenological world of 21 participants, we analyse triangulated data by distinguishing between a range of more ‘ambiguous’ and ‘prescribed’ qualities of experiences. This case study contributes an example of how considering ambiguous and prescribed qualities of experience materials can...

Engaging western landowners in climate change mitigation: a guide to carbon-oriented forest and range management and carbon market opportunities

Science.gov (United States)

David D. Diaz; Susan Charnley; Hannah Gosnell

2009-01-01

There are opportunities for forest owners and ranchers to participate in emerging carbon markets and contribute to climate change mitigation through carbon oriented forest and range management activities. These activities often promote sutainable forestry and ranching and broader conservation goals while having the potential to provide a new income stream for...

A Mitigation Approach to Counter Initial Ranging Based DoS Attacks on IEEE 802.16-2009

International Nuclear Information System (INIS)

Saleem, Y.; Asif, K.H.; Ahmad, T.; Bashir, K.

2013-01-01

In recent years increase in wireless accessed devices does not prerequisite any evidence. Security is the main concern for the researchers in 802.16e now-a-days. The layer structures defines that the security sub-layer resides over the physical layer and provides security on the link layer. This paper discusses the security threats present and still unsolved at the initial network entry stage. A mitigation approach to counter Initial Ranging Based DoS attacks on IEEE 802.16-2009 are particularized in this paper. Furthermore the existing solutions of initial ranging vulnerability are analyzed and their limitations are discussed. Proposed solution was checked against these limitations to ensure their absence. Moreover the solution was implemented in OMNET++ and results were analyzed to ensure the practicality and efficiency. (author)

Localizing Expression of Ambiguity

National Research Council Canada - National Science Library

Bear, John; Hobbs, Sr, Jerry R

1987-01-01

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

Velocity-Aware Handover Management in Two-Tier Cellular Networks

KAUST Repository

Arshad, Rabe; Elsawy, Hesham; Sorour, Sameh; Al-Naffouri, Tareq Y.; Alouini, Mohamed-Slim

2017-01-01

by network densification. Hence, user mobility imposes a nontrivial challenge to harvest capacity gains via network densification. In this paper, we propose a velocity-aware HO management scheme for two-tier downlink cellular network to mitigate the HO effect

Intolerance for approach of ambiguity in social anxiety disorder.

Science.gov (United States)

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

2017-06-01

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

Absence of the Gribov ambiguity in a quadratic gauge

International Nuclear Information System (INIS)

Raval, Haresh

2016-01-01

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

Absence of the Gribov ambiguity in a quadratic gauge

Energy Technology Data Exchange (ETDEWEB)

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

2016-05-15

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

RELATION OF COACHING BEHAVIOR AND ROLE AMBIGUITY

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Karamousalidis G.

2010-08-01

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

Performance of collision damage mitigation braking systems and their effects on human injury in the event of car-to-pedestrian accidents.

Science.gov (United States)

Matsui, Yasuhiro; Han, Yong; Mizuno, Koji

2011-11-01

The number of traffic deaths in Japan was 4,863 in 2010. Pedestrians account for the highest number (1,714, 35%), and vehicle occupants the second highest (1,602, 33%). Pedestrian protection is a key countermeasure to reduce casualties in traffic accidents. A striking vehicle's impact velocity could be considered a parameter influencing the severity of injury and possibility of death in pedestrian crashes. A collision damage mitigation braking system (CDMBS) using a sensor to detect pedestrians could be effective for reducing the vehicle/pedestrian impact velocity. Currently in Japan, cars equipped with the CDMBS also have vision sensors such as a stereo camera for pedestrian detection. However, the ability of vision sensors in production cars to properly detect pedestrians has not yet been established. The effect of reducing impact velocity on the pedestrian injury risk has also not been determined. The first objective of this study is to evaluate the performance of the CDMBS in detecting pedestrians when it is installed in production cars. The second objective of this study is to evaluate the effect of reducing impact velocity on mitigating pedestrian injury. Firstly, impact experiments were performed using a car with the CDMBS in which the car collided with a pedestrian surrogate. In these tests, the velocity was chosen for the various test runs to be 20, 40 and 60 km/h, respectively, which were based on the velocity distribution in real-world pedestrian crashes. The results indicated that the impact velocity reduction ranged approximately from 10 to 15 km/h at the standing location of a pedestrian surrogate at both daytime and nighttime lighting conditions. These results show that the system has the potential to reduce pedestrian casualties from car-to-pedestrian contacts. Secondly, finite-element analyses were performed simulating vehicle-to- pedestrian impacts with the THUMS pedestrian models. The vehicle models selected for the study included a medium sedan

Quantization ambiguity and the Aharanov-Bohm effect

International Nuclear Information System (INIS)

Kunstatter, G.

1983-01-01

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

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

Science.gov (United States)

Calciolari, Stefano; Cantù, Elena; Fattore, Giovanni

2011-01-01

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

Experimental investigation of blast mitigation and particle-blast interaction during the explosive dispersal of particles and liquids

Science.gov (United States)

Pontalier, Q.; Loiseau, J.; Goroshin, S.; Frost, D. L.

2018-04-01

The attenuation of a blast wave from a high-explosive charge surrounded by a layer of inert material is investigated experimentally in a spherical geometry for a wide range of materials. The blast wave pressure is inferred from extracting the blast wave velocity with high-speed video as well as direct measurements with pressure transducers. The mitigant consists of either a packed bed of particles, a particle bed saturated with water, or a homogeneous liquid. The reduction in peak blast wave overpressure is primarily dependent on the mitigant to explosive mass ratio, M/C, with the mitigant material properties playing a secondary role. Relative peak pressure mitigation reduces with distance and for low values of M/C (pressure levels in the mid-to-far field. Solid particles are more effective at mitigating the blast overpressure than liquids, particularly in the near field and at low values of M/C, suggesting that the energy dissipation during compaction, deformation, and fracture of the powders plays an important role. The difference in scaled arrival time of the blast and material fronts increases with M/C and scaled distance, with solid particles giving the largest separation between the blast wave and cloud of particles. Surrounding a high-explosive charge with a layer of particles reduces the positive-phase blast impulse, whereas a liquid layer has no influence on the impulse in the far field. Taking the total impulse due to the blast wave and material impact into account implies that the damage to a nearby structure may actually be augmented for a range of distances. These results should be taken into consideration in the design of explosive mitigant systems.

Inevitable ambiguity in perturbation around flat space-time

International Nuclear Information System (INIS)

Ichinose, S.; Kaminaga, Y.

1989-01-01

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

Hierarchical Morphological Structure and Ambiguity

DEFF Research Database (Denmark)

Vikner, Carl; Vikner, Sten

2008-01-01

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

Representation and productive ambiguity in mathematics and the sciences

CERN Document Server

Grosholz, Emily R

2007-01-01

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

Micro-Doppler Ambiguity Resolution Based on Short-Time Compressed Sensing

Directory of Open Access Journals (Sweden)

Jing-bo Zhuang

2015-01-01

Full Text Available When using a long range radar (LRR to track a target with micromotion, the micro-Doppler embodied in the radar echoes may suffer from ambiguity problem. In this paper, we propose a novel method based on compressed sensing (CS to solve micro-Doppler ambiguity. According to the RIP requirement, a sparse probing pulse train with its transmitting time random is designed. After matched filtering, the slow-time echo signals of the micromotion target can be viewed as randomly sparse sampling of Doppler spectrum. Select several successive pulses to form a short-time window and the CS sensing matrix can be built according to the time stamps of these pulses. Then performing Orthogonal Matching Pursuit (OMP, the unambiguous micro-Doppler spectrum can be obtained. The proposed algorithm is verified using the echo signals generated according to the theoretical model and the signals with micro-Doppler signature produced using the commercial electromagnetic simulation software FEKO.

Removing Ambiguities of IP Telephony Traffic Using Protocol Scrubbers

Directory of Open Access Journals (Sweden)

Bazara I. A. Barry

2012-10-01

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

PENGARUH ROLE AMBIGUITY DAN ROLE CONFLICT TERHADAP KOMITMEN INDEPENDENSI AUDITOR INTERNAL

Directory of Open Access Journals (Sweden)

Angga Prasetyo

2011-05-01

Full Text Available This study aims to determine the influence of role conflict (role conflict against the commitmentof internal auditors’ independence, and know the effect of role ambiguity (role ambiguity ofthe Internal Auditor independence commitment. Data was collected through primary method byusing a questionnaire. Then performed the data analysis that includes classical assumption test,F test, t test, and analysis of coefficient of determination (R2. To analyze using SPSS softwareversion 16. Based on research result shows that role conflict has a significant negative effect oncommitment to the independence of internal auditors, and role ambiguity (role ambiguity has asignificant negative effect on commitment to the independence of internal auditors. While basedon simultaneous test (F test, role conflict (role conflict and role ambiguity (role ambiguity havean influence on the commitment of internal auditor independence.

Rainbow-shift mechanism behind discrete optical-potential ambiguities

International Nuclear Information System (INIS)

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

1991-01-01

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

Resolving the ambiguities: An industrial hygiene Indoor Air Quality (IAQ) symposium

Energy Technology Data Exchange (ETDEWEB)

Gammage, R.B.

1995-01-01

Resolving the Ambiguities: An Industrial Hygiene (IAQ) Symposium was a one-day event designed to inform practicing industrial hygienists about highlight presentations made at Indoor Air `93. A broad range of topics was presented by invited speakers. Topics included were attempts to deal with guidelines and standards, questionnaires, odors and sensory irritation, respiratory allergies, neuroses, sick building syndrome (SBS), and multiple chemical sensitivity (MCS).

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

Science.gov (United States)

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

2015-10-01

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

Cognitive Flexibility Supports Preschoolers' Detection of Communicative Ambiguity

Science.gov (United States)

Gillis, Randall; Nilsen, Elizabeth S.

2014-01-01

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

On the ambiguity in relativistic tidal deformability

Science.gov (United States)

Gralla, Samuel E.

2018-04-01

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

Relation between nonlinear models and gauge ambiguities

International Nuclear Information System (INIS)

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

1980-01-01

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

An Investigation into Ambiguity Tolerance in Iranian Senior EFL Undergraduates

Science.gov (United States)

Marzban, Amin; Barati, Hossein; Moinzadeh, Ahmad

2012-01-01

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

Robust portfolio choice with ambiguity and learning about return predictability

DEFF Research Database (Denmark)

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

2013-01-01

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

Surgical aspects of ambiguous genitalia associated with congenital ...

African Journals Online (AJOL)

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

Sensory memory for ambiguous vision.

Science.gov (United States)

Pearson, Joel; Brascamp, Jan

2008-09-01

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

Ambiguity resolution in systems using Omega for position location

Science.gov (United States)

Frenkel, G.; Gan, D. G.

1974-01-01

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

A Lexical Analysis Tool with Ambiguity Support

OpenAIRE

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

2012-01-01

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

De morseir syndrome presenting as ambiguous genitalia

OpenAIRE

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

2012-01-01

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

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

Science.gov (United States)

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.

Water velocity meter

Science.gov (United States)

Roberts, C. W.; Smith, D. L.

1970-01-01

Simple, inexpensive drag sphere velocity meter with a zero to 6 ft/sec range measures steady-state flow. When combined with appropriate data acquisition system, it is suited to applications where large numbers of simultaneous measurements are needed for current mapping or velocity profile determination.

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

Science.gov (United States)

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

2017-08-15

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

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

Science.gov (United States)

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.

Finding meaning in art: Preferred levels of ambiguity in art appreciation

Science.gov (United States)

Jakesch, Martina; Leder, Helmut

2011-01-01

Uncertainty is typically not desirable in everyday experiences, but uncertainty in the form of ambiguity may be a defining feature of aesthetic experiences of modern art. In this study, we examined different hypotheses concerning the quantity and quality of information appreciated in art. Artworks were shown together with auditorily presented statements. We tested whether the amount of information, the amount of matching information, or the proportion of matching to nonmatching statements apparent in a picture (levels of ambiguity) affect liking and interestingness. Only the levels of ambiguity predicted differences in the two dependent variables. These findings reveal that ambiguity is an important determinant of aesthetic appreciation and that a certain level of ambiguity is appreciable. PMID:19565431

Children's Comprehension of Two Types of Syntactic Ambiguity

Science.gov (United States)

Zimmer, Elly Jane

2017-01-01

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

Ambiguous sets of partial wave amplitudes can intersect

International Nuclear Information System (INIS)

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

1976-01-01

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

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

Science.gov (United States)

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

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

A coaxial plasma gun with a controllable streaming velocity in the range of 2-90 km secsup(-1)

International Nuclear Information System (INIS)

Venkataramani, N.; Mattoo, S.K.

1981-01-01

A coaxial plasma gun capable of producing a plasma stream of velocity ranging between 2 and 90 km secsup(-1) is described. The velocity of the stream is controlled by a variable (0.2-25 Ω) NaCl salt solution resistor in the discharge path of the energy storage connected across the gun. The resistor dissipates an energy of 200 J in the gun discharge current pulse period of 25 μ sec and the consequent heating and dissociation of the electrolyte are insignificant. The electron density of the plasma stream ranges between 10 18 and 10 19 msup(-3) and the temperature is approximately 10 eV. The total number of ions per plasma pulse is approximately 10 18 . The energy transfer efficiency of the gun is approximately 10%. The low transfer efficiency is explained in terms of the experimental requirements and the performance of the valve which admits gas into the gun region. For evaluation of the performance of the gun, several diagnostics have been deployed. A specially designed high voltage capacitor probe is described. (author)

An ambiguity in one-loop quantum gravity

International Nuclear Information System (INIS)

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

1980-01-01

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

Generalized dynamic model and control of ambiguous mono axial vehicle robot

Directory of Open Access Journals (Sweden)

Frantisek Duchon

2016-09-01

Full Text Available This article deals with the novel concept of ambiguous mono axial vehicle robot. Such robot is a combination of Segway and dicycle, which utilizes the advantages of each chassis. The advantage of dicycle is lower energy consumption during the movement and the higher safety of carried payload. The movable platform inside the ambiguous mono axial vehicle allows using the various sensors or devices. This will change the ambiguous mono axial vehicle to the Segway type robot. Both these modes are necessary to control in the stable mode to ensure the safety of the ambiguous mono axial vehicle’s movement. The main contents of the article contain description of generalized dynamic model of ambiguous mono axial vehicle and related control of ambiguous mono axial vehicle. The proposal is unique in that the same controller is used for both modes. Several simulations verify proposed control schemes and identified parameters. Moreover, the dicycle type of platform has never been used in robotics and that is another novelty.

Scheme-scale ambiguity in analysis of QCD observable

International Nuclear Information System (INIS)

Mirjalili, A.; Kniehl, B.A.

2010-01-01

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

Renormalization ambiguities and conformal anomaly in metric-scalar backgrounds

International Nuclear Information System (INIS)

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

2006-01-01

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

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

Science.gov (United States)

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

2016-05-25

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

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

Directory of Open Access Journals (Sweden)

Chao Tang

2017-09-01

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

Ambiguities of the phase analysis of the proton-proton scattering amplitude

International Nuclear Information System (INIS)

Grebenyuk, O.G.; Shklyarevskij, G.M.

1980-01-01

Ambiguities of the phase analysis of the proton-proton scattering amplitude are analysed. It is shown that for five measurements of polarization parameters sets there are ambiguities similar to the Gersten ambiguities in the phase analysis of πN scattering. A problem on additional experiments needed to eliminate these ambiguities is investigated. It is shown that for this purpose it suffices to measure three total cross sections with polarized and nonpolarized protons, thus determining the imaginary parts of amplitudes at THETA=0 and polarization parameters

Ambiguity Tolerance in Organizations: Definitional Clarification and Perspectives on Future Research

Directory of Open Access Journals (Sweden)

David L Mclain

2015-04-01

Full Text Available 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.

Ambiguity in urban belonging

DEFF Research Database (Denmark)

Koefoed, Lasse Martin; Simonsen, Kirsten

2015-01-01

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

Crichton's phase-shift ambiguity

NARCIS (Netherlands)

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

1973-01-01

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

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

African Journals Online (AJOL)

Administrator

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

Good luck, bad luck, and ambiguity aversion

OpenAIRE

Briony D. Pulford; Poonam Gill

2014-01-01

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

Quantization ambiguity and non-trivial vacuum structure

International Nuclear Information System (INIS)

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

1978-01-01

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

Attitudes toward risk and ambiguity in patients with autism spectrum disorder.

Science.gov (United States)

Fujino, Junya; Tei, Shisei; Hashimoto, Ryu-Ichiro; Itahashi, Takashi; Ohta, Haruhisa; Kanai, Chieko; Okada, Rieko; Kubota, Manabu; Nakamura, Motoaki; Kato, Nobumasa; Takahashi, Hidehiko

2017-01-01

Although the ability to make optimal decisions under uncertainty is an integral part of everyday life, individuals with autism spectrum disorder (ASD) frequently report that they experience difficulties with this skill. In behavioral economics, researchers distinguish two types of uncertainty to understand decision-making in this setting: risk (known probabilities) and ambiguity (unknown probabilities). However, it remains unclear how individuals with ASD behave under risk and ambiguity, despite growing evidence of their altered decision-making under uncertainty. We therefore extended previous research by studying the attitudes of those with ASD toward risk and ambiguity in both positive and negative contexts (i.e., gain and loss). In gain contexts, no significant difference was observed between the groups in risk attitudes, but ambiguity aversion was attenuated in ASD. In loss contexts, ambiguity attitudes did not significantly differ between the groups, but the ASD participants were less risk-seeking compared with the controls. In addition, insensitivity to the context change under risk and ambiguity in ASD was both significantly associated with poor social skills. These results improve our understanding of altered decision-making under uncertainty by disentangling the attitudes toward risk and ambiguity in ASD individuals. Applying behavioral economic tools may provide insights into the mechanisms underlying behavioral disturbances in ASD.

Computational Humour : Utilizing Cross-Reference Ambiguity for Conversational Jokes

NARCIS (Netherlands)

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

2007-01-01

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

Roles of frontal and temporal regions in reinterpreting semantically ambiguous sentences

Directory of Open Access Journals (Sweden)

Sylvia eVitello

2014-07-01

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

The Learning Teacher: Role of Ambiguity in Education

Science.gov (United States)

Suzawa, Gilbert S.

2013-01-01

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

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

Science.gov (United States)

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. © The Author(s) 2015.

Coherent lidar modulated with frequency stepped pulse trains for unambiguous high duty cycle range and velocity sensing in the atmosphere

DEFF Research Database (Denmark)

Lindelöw, Per Jonas Petter; Mohr, Johan Jacob

2007-01-01

Range unambiguous high duty cycle coherent lidars can be constructed based on frequency stepped pulse train modulation, even continuously emitting systems could be envisioned. Such systems are suitable for velocity sensing of dispersed targets, like the atmosphere, at fast acquisition rates....... The lightwave synthesized frequency sweeper is a suitable generator yielding fast pulse repetition rates and stable equidistant frequency steps. Theoretical range resolution profiles of modulated lidars are presented....

Semantic ambiguity effects on traditional Chinese character naming: A corpus-based approach.

Science.gov (United States)

Chang, Ya-Ning; Lee, Chia-Ying

2017-11-09

Words are considered semantically ambiguous if they have more than one meaning and can be used in multiple contexts. A number of recent studies have provided objective ambiguity measures by using a corpus-based approach and have demonstrated ambiguity advantages in both naming and lexical decision tasks. Although the predictive power of objective ambiguity measures has been examined in several alphabetic language systems, the effects in logographic languages remain unclear. Moreover, most ambiguity measures do not explicitly address how the various contexts associated with a given word relate to each other. To explore these issues, we computed the contextual diversity (Adelman, Brown, & Quesada, Psychological Science, 17; 814-823, 2006) and semantic ambiguity (Hoffman, Lambon Ralph, & Rogers, Behavior Research Methods, 45; 718-730, 2013) of traditional Chinese single-character words based on the Academia Sinica Balanced Corpus, where contextual diversity was used to evaluate the present semantic space. We then derived a novel ambiguity measure, namely semantic variability, by computing the distance properties of the distinct clusters grouped by the contexts that contained a given word. We demonstrated that semantic variability was superior to semantic diversity in accounting for the variance in naming response times, suggesting that considering the substructure of the various contexts associated with a given word can provide a relatively fine scale of ambiguity information for a word. All of the context and ambiguity measures for 2,418 Chinese single-character words are provided as supplementary materials.

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

NARCIS (Netherlands)

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

2013-01-01

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

De morseir syndrome presenting as ambiguous genitalia

Directory of Open Access Journals (Sweden)

Anubhav Thukral

2012-01-01

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

De morseir syndrome presenting as ambiguous genitalia.

Science.gov (United States)

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

2012-12-01

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

Discriminating Between Models of Ambiguity Attitude : A Qualitative Test

NARCIS (Netherlands)

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

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

Neural responses to ambiguity involve domain-general and domain-specific emotion processing systems.

Science.gov (United States)

Neta, Maital; Kelley, William M; Whalen, Paul J

2013-04-01

Extant research has examined the process of decision making under uncertainty, specifically in situations of ambiguity. However, much of this work has been conducted in the context of semantic and low-level visual processing. An open question is whether ambiguity in social signals (e.g., emotional facial expressions) is processed similarly or whether a unique set of processors come on-line to resolve ambiguity in a social context. Our work has examined ambiguity using surprised facial expressions, as they have predicted both positive and negative outcomes in the past. Specifically, whereas some people tended to interpret surprise as negatively valenced, others tended toward a more positive interpretation. Here, we examined neural responses to social ambiguity using faces (surprise) and nonface emotional scenes (International Affective Picture System). Moreover, we examined whether these effects are specific to ambiguity resolution (i.e., judgments about the ambiguity) or whether similar effects would be demonstrated for incidental judgments (e.g., nonvalence judgments about ambiguously valenced stimuli). We found that a distinct task control (i.e., cingulo-opercular) network was more active when resolving ambiguity. We also found that activity in the ventral amygdala was greater to faces and scenes that were rated explicitly along the dimension of valence, consistent with findings that the ventral amygdala tracks valence. Taken together, there is a complex neural architecture that supports decision making in the presence of ambiguity: (a) a core set of cortical structures engaged for explicit ambiguity processing across stimulus boundaries and (b) other dedicated circuits for biologically relevant learning situations involving faces.

Resolution of ambiguities in perturbative QCD

International Nuclear Information System (INIS)

Nakkagawa, Hisao; Niegawa, Akira.

1984-01-01

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

Increasing Statistical Literacy by Exploiting Lexical Ambiguity of Technical Terms

Directory of Open Access Journals (Sweden)

Jennifer Kaplan

2018-01-01

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

Normal ranges and test-retest reproducibility of flow and velocity parameters in intracranial arteries measured with phase-contrast magnetic resonance imaging

International Nuclear Information System (INIS)

Correia de Verdier, Maria; Wikstroem, Johan

2016-01-01

The purpose of the present study was to investigate normal ranges and test-retest reproducibility of phase-contrast MRI (PC-MRI)-measured flow and velocity parameters in intracranial arteries. Highest flow (HF), lowest flow (LF), peak systolic velocity (PSV), and end diastolic velocity (EDV) were measured at two dates in the anterior (ACA), middle (MCA), and posterior (PCA) cerebral arteries of 30 healthy volunteers using two-dimensional PC-MRI at 3 T. Least detectable difference (LDD) was calculated. In the left ACA, HF was (mean (range, LDD)) 126 ml/min (36-312, 59 %), LF 61 ml/min (0-156, 101 %), PSV 64 cm/s (32-141, 67 %), and EDV 35 cm/s (18-55, 42 %); in the right ACA, HF was 154 ml/min (42-246, 49 %), LF 77 ml/min (0-156, 131 %), PSV 75 cm/s (26-161, 82 %), and EDV 39 cm/s (7-59, 67 %). In the left MCA, HF was 235 ml/min (126-372, 35 %), LF 116 ml/min (42-186, 48 %), PSV 90 cm/s (55-183, 39 %), and EDV 46 cm/s (20-66, 28 %); in the right MCA, HF was 238 ml/min (162-342, 44 %), LF 120 ml/min (72-216, 48 %), PSV 88 cm/s (55-141, 35 %), and EDV 45 cm/s (26-67, 23 %). In the left PCA, HF was 108 ml/min (42-168, 54 %), LF 53 ml/min (18-108, 64 %), PSV 50 cm/s (24-77, 63 %), and EDV 28 cm/s (14-40, 45 %); in the right PCA, HF was 98 ml/min (30-162, 49 %), LF 49 ml/min (12-84, 55 %), PSV 47 cm/s (27-88, 59 %), and EDV 27 cm/s (16-41, 45 %). PC-MRI-measured flow and velocity parameters in the main intracranial arteries have large normal ranges. Reproducibility is highest in MCA. (orig.)

Normal ranges and test-retest reproducibility of flow and velocity parameters in intracranial arteries measured with phase-contrast magnetic resonance imaging

Energy Technology Data Exchange (ETDEWEB)

Correia de Verdier, Maria; Wikstroem, Johan [Uppsala University Hospital, Department of Radiology, Uppsala University, Uppsala (Sweden)

2016-05-15

The purpose of the present study was to investigate normal ranges and test-retest reproducibility of phase-contrast MRI (PC-MRI)-measured flow and velocity parameters in intracranial arteries. Highest flow (HF), lowest flow (LF), peak systolic velocity (PSV), and end diastolic velocity (EDV) were measured at two dates in the anterior (ACA), middle (MCA), and posterior (PCA) cerebral arteries of 30 healthy volunteers using two-dimensional PC-MRI at 3 T. Least detectable difference (LDD) was calculated. In the left ACA, HF was (mean (range, LDD)) 126 ml/min (36-312, 59 %), LF 61 ml/min (0-156, 101 %), PSV 64 cm/s (32-141, 67 %), and EDV 35 cm/s (18-55, 42 %); in the right ACA, HF was 154 ml/min (42-246, 49 %), LF 77 ml/min (0-156, 131 %), PSV 75 cm/s (26-161, 82 %), and EDV 39 cm/s (7-59, 67 %). In the left MCA, HF was 235 ml/min (126-372, 35 %), LF 116 ml/min (42-186, 48 %), PSV 90 cm/s (55-183, 39 %), and EDV 46 cm/s (20-66, 28 %); in the right MCA, HF was 238 ml/min (162-342, 44 %), LF 120 ml/min (72-216, 48 %), PSV 88 cm/s (55-141, 35 %), and EDV 45 cm/s (26-67, 23 %). In the left PCA, HF was 108 ml/min (42-168, 54 %), LF 53 ml/min (18-108, 64 %), PSV 50 cm/s (24-77, 63 %), and EDV 28 cm/s (14-40, 45 %); in the right PCA, HF was 98 ml/min (30-162, 49 %), LF 49 ml/min (12-84, 55 %), PSV 47 cm/s (27-88, 59 %), and EDV 27 cm/s (16-41, 45 %). PC-MRI-measured flow and velocity parameters in the main intracranial arteries have large normal ranges. Reproducibility is highest in MCA. (orig.)

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

Science.gov (United States)

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

2017-06-01

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

Confronting Ambiguity in Science

Science.gov (United States)

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

2015-01-01

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

Li Shangyin and the Art of Poetic Ambiguity

Directory of Open Access Journals (Sweden)

Maja Lavrač

2016-12-01

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

Process ambiguities in Sino-Danish Business Negotiations

DEFF Research Database (Denmark)

Kumar, Rajesh; Worm, Verner

2004-01-01

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

The classification of ambiguity in polarimetric reconstruction of coronal mass ejection

International Nuclear Information System (INIS)

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

2014-01-01

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

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

Science.gov (United States)

Bright, Larry K.; Mahdi, Ghada S.

2012-01-01

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

Effective potential for bilocal composite fields and its ambiguity

International Nuclear Information System (INIS)

Muta, T.

1988-01-01

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

Examining English-German Translation Ambiguity Using Primed Translation Recognition

Science.gov (United States)

Eddington, Chelsea M.; Tokowicz, Natasha

2013-01-01

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

Quantification Scope Ambiguity Resolution: Evidence from Persian and English

Science.gov (United States)

Asadollahfam, Hassan; Lotfi, Ahmad Reza

2010-01-01

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

Azimuth Ambiguities Removal in Littoral Zones Based on Multi-Temporal SAR Images

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Xiangguang Leng

2017-08-01

Full Text Available Synthetic aperture radar (SAR is one of the most important techniques for ocean monitoring. Azimuth ambiguities are a real problem in SAR images today, which can cause performance degradation in SAR ocean applications. In particular, littoral zones can be strongly affected by land-based sources, whereas they are usually regions of interest (ROI. Given the presence of complexity and diversity in littoral zones, azimuth ambiguities removal is a tough problem. As SAR sensors can have a repeat cycle, multi-temporal SAR images provide new insight into this problem. A method for azimuth ambiguities removal in littoral zones based on multi-temporal SAR images is proposed in this paper. The proposed processing chain includes co-registration, local correlation, binarization, masking, and restoration steps. It is designed to remove azimuth ambiguities caused by fixed land-based sources. The idea underlying the proposed method is that sea surface is dynamic, whereas azimuth ambiguities caused by land-based sources are constant. Thus, the temporal consistence of azimuth ambiguities is higher than sea clutter. It opens up the possibilities to use multi-temporal SAR data to remove azimuth ambiguities. The design of the method and the experimental procedure are based on images from the Sentinel data hub of Europe Space Agency (ESA. Both Interferometric Wide Swath (IW and Stripmap (SM mode images are taken into account to validate the proposed method. This paper also presents two RGB composition methods for better azimuth ambiguities visualization. Experimental results show that the proposed method can remove azimuth ambiguities in littoral zones effectively.

Emergence in extinction of enhanced and persistent responding to ambiguous aversive cues is associated with high MAOA activity in the prelimbic cortex

Directory of Open Access Journals (Sweden)

Guillaume L. Poirier

2016-12-01

Full Text Available There is a great deal of individual variability in the emotional outcomes of potentially traumatic events, and the underlying mechanisms are only beginning to be understood. In order to further our understanding of individual trajectories to trauma, its vulnerability and resilience, we adapted a model of fear expression to ambiguous vs perfect cues in adult male rats, and examined long-term fear extinction, 2, 3, and 50 days from acquisition. After the final conditioned fear test, mitochondrial enzyme monoamine oxidase A (MAOA function was examined. In order to identify associations between this function and behavioral expression, an a posteri median segregation approach was adopted, and animals were classified as high or low responding according to level of freezing to the ambiguous cue at remote testing, long after the initial extinction. Those individuals characterized by their higher response showed a freezing pattern that persisted from their previous extinction sessions, in spite of their acquisition levels being equivalent to the low-freezing group. Furthermore, unlike more adaptive individuals, freezing levels of high-freezing animals even increased at initial extinction, to almost double their acquisition session levels. Controlling for perfect cue response at remote extinction, greater ambiguous threat cue response was associated with enhanced prelimbic cortex MAOA functional activity. These findings underscore MAOA as a potential target for the development of interventions to mitigate the impact of traumatic experiences.

Phase ambiguity resolution for offset QPSK modulation systems

Science.gov (United States)

Nguyen, Tien M. (Inventor)

1991-01-01

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

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

Science.gov (United States)

Haro, Juan; Ferré, Pilar

2018-06-01

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

The Benefit of Ambiguity in Understanding Goals in Requirements Modelling

DEFF Research Database (Denmark)

Paay, Jeni; Pedell, Sonja; Sterling, Leon

2011-01-01

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

Extent of the Immirzi ambiguity in quantum general relativity

International Nuclear Information System (INIS)

Marugan, Guillermo A Mena

2002-01-01

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

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

Science.gov (United States)

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

2012-01-01

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

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

NARCIS (Netherlands)

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

2007-01-01

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

High energy collisions and the proton structure: an ambiguity

International Nuclear Information System (INIS)

Franca, H.M.

1980-01-01

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

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

Science.gov (United States)

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

2016-01-01

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

Auditory velocity discrimination in the horizontal plane at very high velocities.

Science.gov (United States)

Frissen, Ilja; Féron, François-Xavier; Guastavino, Catherine

2014-10-01

We determined velocity discrimination thresholds and Weber fractions for sounds revolving around the listener at very high velocities. Sounds used were a broadband white noise and two harmonic sounds with fundamental frequencies of 330 Hz and 1760 Hz. Experiment 1 used velocities ranging between 288°/s and 720°/s in an acoustically treated room and Experiment 2 used velocities between 288°/s and 576°/s in a highly reverberant hall. A third experiment addressed potential confounds in the first two experiments. The results show that people can reliably discriminate velocity at very high velocities and that both thresholds and Weber fractions decrease as velocity increases. These results violate Weber's law but are consistent with the empirical trend observed in the literature. While thresholds for the noise and 330 Hz harmonic stimulus were similar, those for the 1760 Hz harmonic stimulus were substantially higher. There were no reliable differences in velocity discrimination between the two acoustical environments, suggesting that auditory motion perception at high velocities is robust against the effects of reverberation. Copyright © 2014 Elsevier B.V. All rights reserved.

Smart disaster mitigation in Thailand

Science.gov (United States)

Aimmanee, S.; Ekkawatpanit, C.; Asanuma, H.

2016-04-01

Thailand is notoriously exposed to several natural disasters, from heavy thunder storms to earthquakes and tsunamis, since it is located in the tropical area and has tectonic cracks underneath the ground. Besides these hazards flooding, despite being less severe, occurs frequently, stays longer than the other disasters, and affects a large part of the national territory. Recently in 2011 have also been recorded the devastating effects of major flooding causing the economic damages and losses around 50 billion dollars. Since Thailand is particularly exposed to such hazards, research institutions are involved in campaigns about monitoring, prevention and mitigation of the effects of such phenomena, with the aim to secure and protect human lives, and secondly, the remarkable cultural heritage. The present paper will first make a brief excursus on the main Thailand projects aimed at the mitigation of natural disasters, referring to projects of national and international relevance, being implemented, such as the ESCAP1999 (flow regime regulation and water conservation). Adaptable devices such as foldable flood barriers and hydrodynamically supported temporary banks have been utilized when flooding. In the second part of the paper, will be described some new ideas concerning the use of smart and biomimicking column structures capable of high-velocity water interception and velocity detection in the case of tsunami. The pole configuration is composite cylindrical shell structure embedded with piezoceramic sensor. The vortex shedding of the flow around the pole induces the vibration and periodically strains the piezoelectric element, which in turn generates the electrical sensorial signal. The internal space of the shell is filled with elastic foam to enhance the load carrying capability due to hydrodynamic application. This more rigid outer shell inserted with soft core material resemble lotus stem in nature in order to prolong local buckling and ovalization of column

Human Perception of Ambiguous Inertial Motion Cues

Science.gov (United States)

Zhang, Guan-Lu

2010-01-01

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

Bank risk, bailouts and ambiguity

NARCIS (Netherlands)

Nijskens, R.G.M.

2012-01-01

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

A sextupole-magnet as variable velocity selector for paramagnetic atomic beams in the thermal range

International Nuclear Information System (INIS)

Spindler, G.; Ebinghaus, H.; Steffens, E.

1974-01-01

The possibility of employing a sextupole-magnet as a velocity selector on account of its velocity dependent focusing properties for paramagnetic atomic beams is investigated. In comparison with a traditional velocity selector with rotating disks, a sextupole-magnet as velocity selector has the advantage of additional focusing and polarizing the atomic beam. Moreover it suppresses polymer molecules without an effective magnetic momentum of the electronic shell

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

Science.gov (United States)

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. © 2016 The Protein Society.

Greenhouse gas mitigation potential of biomass energy technologies in Vietnam using the long range energy alternative planning system model

International Nuclear Information System (INIS)

Kumar, Amit; Bhattacharya, S.C.; Pham, H.L.

2003-01-01

The greenhouse gas (GHG) mitigation potentials of number of selected Biomass Energy Technologies (BETs) have been assessed in Vietnam. These include Biomass Integrated Gasification Combined Cycle (BIGCC) based on wood and bagasse, direct combustion plants based on wood, co-firing power plants and Stirling engine based on wood and cooking stoves. Using the Long-range Energy Alternative Planning (LEAP) model, different scenarios were considered, namely the base case with no mitigation options, replacement of kerosene and liquefied petroleum gas (LPG) by biogas stove, substitution of gasoline by ethanol in transport sector, replacement of coal by wood as fuel in industrial boilers, electricity generation with biomass energy technologies and an integrated scenario including all the options together. Substitution of coal stoves by biogas stove has positive abatement cost, as the cost of wood in Vietnam is higher than coal. Replacement of kerosene and LPG cookstoves by biomass stove also has a positive abatement cost. Replacement of gasoline by ethanol can be realized after a few years, as at present the cost of ethanol is more than the cost of gasoline. The replacement of coal by biomass in industrial boiler is also not an attractive option as wood is more expensive than coal in Vietnam. The substitution of fossil fuel fired plants by packages of BETs has a negative abatement cost. This option, if implemented, would result in mitigation of 10.83 million tonnes (Mt) of CO 2 in 2010

The ambiguity of simplicity in quantum and classical simulation

International Nuclear Information System (INIS)

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

2017-01-01

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

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

International Nuclear Information System (INIS)

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

1977-01-01

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

Origin of the Gribov ambiguity

International Nuclear Information System (INIS)

Takahashi, Y.; Kobayashi, M.

1978-01-01

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

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

Science.gov (United States)

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

2011-01-01

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

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

Science.gov (United States)

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

2013-01-01

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

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

International Nuclear Information System (INIS)

Fabbrichesi, M.E.

1987-01-01

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

Pericentric Inversion of Chromosome 9 in an Infant With Ambiguous Genitalia.

Science.gov (United States)

Sotoudeh, Arya; Rostami, Parastoo; Nakhaeimoghadam, Maryam; Mohsenipour, Reihaneh; Rezaei, Nima

2017-10-01

Pericentric inversion of Chromosome 9 is one of the most common chromosomal abnormalities, which could be associated with various manifestations in some cases. Herein, a patient is presented with ambiguous genitalia that karyotyping revealed pericentric inversion of Chromosome 9 (p12,q13). Pericentric inversion of Chromosome 9 could be considered in the list of differential diagnosis of those with ambiguous genitalia, while chromosomal karyotype and culture could be recommended in children with ambiguous genitalia.

Speak Clearly, If You Speak at All; Carve Every Word Before You Let It Fall: Problems of Ambiguous Terminology in eLearning System Development

Directory of Open Access Journals (Sweden)

Damian Gordon

2014-06-01

Full Text Available This paper addresses issues associated with the development of eLearning software systems. The development of software systems in general is a highly complex process, and a number of methodologies and models have been developed to help address some of these complexities. Generally the first stage in most development processes is the gathering of requirements which involves elicitation from end-users. This process is made more complex by problems associated with ambiguous terminology. Types of ambiguous terminology include homonymous, polysemous and inaccurate terms. This range of ambiguous terminology can cause significant misunderstandings in the requirements gathering process, which in turn can lead to software systems that do not meet the requirements of the end-users. This research seeks to explore some of the more common terms that can be ambiguously interpreted in the development of eLearning systems, and suggests software engineering approaches to help alleviate the potentially erroneous outcomes of these ambiguities.

Novel Method of Unambiguous Moving Target Detection in Pulse-Doppler Radar with Random Pulse Repetition Interval

Directory of Open Access Journals (Sweden)

Liu Zhen

2012-03-01

Full Text Available Blind zones and ambiguities in range and velocity measurement are two important issues in traditional pulse-Doppler radar. By generating random deviations with respect to a mean Pulse Repetition Interval (PRI, this paper proposes a novel algorithm of Moving Target Detection (MTD based on the Compressed Sensing (CS theory, in which the random deviations of the PRIare converted to the Restricted Isometry Property (RIP of the observing matrix. The ambiguities of range and velocity are eliminated by designing the signal parameters. The simulation results demonstrate that this scheme has high performance of detection, and there is no ambiguity and blind zones as well. It can also shorten the coherent processing interval compared to traditional staggered PRI mode because only one pulse train is needed instead of several trains.

Comparing the ambiguity reduction abilities of probabilistic context-free grammars

NARCIS (Netherlands)

Infante-Lopez, G.G.; de Rijke, M.

2004-01-01

We present a measure for evaluating Probabilistic Context Free Grammars (PCFG) based on their ambiguity resolution capabilities.Probabilities in a PCFG can be seen as a filtering mechanism: For an ambiguous sentence, the trees bearing maximum probability aresingle out, while all others are

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

Energy Technology Data Exchange (ETDEWEB)

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.

Optimal observables and phase-space ambiguities

International Nuclear Information System (INIS)

Nachtmann, O.; Nagel, F.

2005-01-01

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

On ambiguities in the exponentiation of large QCD perturbative corrections

International Nuclear Information System (INIS)

Chyla, Jiri

1986-01-01

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

Ambiguities of the natural gauge in Yang-Mills theories

International Nuclear Information System (INIS)

Lazarides, G.

1978-01-01

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

Clock ambiguity and the emergence of physical laws

International Nuclear Information System (INIS)

Albrecht, Andreas; Iglesias, Alberto

2008-01-01

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

Sensorimotor Adaptations Following Exposure to Ambiguous Inertial Motion Cues

Science.gov (United States)

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

2009-01-01

The central nervous system must resolve the ambiguity of inertial motion sensory cues in order to derive accurate spatial orientation awareness. We hypothesize that multi-sensory integration will be adaptively optimized in altered gravity environments based on the dynamics of other sensory information available, with greater changes in otolith-mediated responses in the mid-frequency range where there is a crossover of tilt and translation responses. The primary goals of this ground-based research investigation are to explore physiological mechanisms and operational implications of tilt-translation disturbances during and following re-entry, and to evaluate a tactile prosthesis as a countermeasure for improving control of whole-body orientation.

Ambiguity Tolerance and Perceptual Learning Styles of Chinese EFL Learners

Science.gov (United States)

Li, Haishan; He, Qingshun

2016-01-01

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

Tracking Down the Origins of Ambiguity in Context-Free Grammars

NARCIS (Netherlands)

H.J.S. Basten (Bas)

2010-01-01

htmlabstractContext-free grammars are widely used but still hindered by ambiguity. This stresses the need for detailed detection methods that point out the sources of ambiguity in a grammar. In this paper we show how the approximative Noncanonical Unambiguity Test by Schmitz can be extended to

Ambiguity Function Analysis and Processing for Passive Radar Based on CDR Digital Audio Broadcasting

Directory of Open Access Journals (Sweden)

Zhang Qiang

2015-01-01

Full Text Available China Digital Radio (CDR broadcasting is a new standard of digital audio broadcasting of FM frequency (87–108 MHz based on our research and development efforts. It is compatible with the frequency spectrum in analog FM radio and satisfies the requirements for smooth transition from analog to digital signal in FM broadcasting in China. This paper focuses on the signal characteristics and processing methods of radio-based passive radar. The signal characteristics and ambiguity function of a passive radar illumination source are analyzed. The adverse effects on the target detection of the side peaks owing to cyclic prefix, the Doppler ambiguity strips because of signal synchronization, and the range of side peaks resulting from the signal discontinuous spectrum are then studied. Finally, methods for suppressing these side peaks are proposed and their effectiveness is verified by simulations.

The ambiguity of simplicity in quantum and classical simulation

Energy Technology Data Exchange (ETDEWEB)

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

2017-04-11

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

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

Science.gov (United States)

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

2017-01-01

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

The Inhibitory Mechanism in Learning Ambiguous Words in a Second Language

Directory of Open Access Journals (Sweden)

Baoguo Chen

2017-04-01

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

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

Science.gov (United States)

Nguyen, Tien Manh

1989-01-01

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

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

Science.gov (United States)

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

2007-01-01

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

Mitigation of Flood Hazards Through Modification of Urban Channels and Floodplains

Science.gov (United States)

Miller, A. J.; Lee, G.; Bledsoe, B. P.; Stephens, T.

2017-12-01

Small urban watersheds with high percent impervious cover and dense road and storm-drain networks are highly responsive to short-duration high-intensity rainfall events that lead to flash floods. The Baltimore metropolitan area has some of the flashiest urban watersheds in the conterminous U.S., high frequency of channel incision in affected areas, and a large number of watershed restoration projects designed to restore ecosystem services through reconnection of the channel with the floodplain. A question of key importance in these and other urban watersheds is to what extent we can mitigate flood hazards and urban stream syndrome through restoration activities that modify the channel and valley floor. Local and state governments have invested resources in repairing damage caused by extreme events like the July 30, 2016 Ellicott City flood in the Tiber River watershed, as well as more frequent high flows in other local urban streams. Recent reports have investigated how much flood mitigation may be achieved through modification of the channel and floodplain to enhance short-term storage of flood waters on the valley floor or in other subsurface structures, as compared with increasing stormwater management in the headwaters. Ongoing research conducted as part of the UWIN (Urban Water Innovation Network) program utilizes high-resolution topographic point clouds derived by processing of photographs from hand-held cameras or video frames from drone overflights. These are used both to track geomorphic change and to assess flood response with 2d hydraulic modeling tools under alternative mitigation scenarios. Assessment metrics include variations in inundation extent, water depth, hydrograph attenuation, and temporal and spatial characteristics of the 2d depth-averaged velocity field. Examples from diverse urban watersheds are presented to illustrate the range of anticipated outcomes and potential constraints on the effectiveness of downstream vs. headwater mitigation

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

NARCIS (Netherlands)

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

2015-01-01

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

Evaluation of ambiguous genitalia with MR imaging

International Nuclear Information System (INIS)

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

1989-01-01

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

Lexical ambiguity resolution during sentence processing in Parkinson's disease: An event-related potential study.

Directory of Open Access Journals (Sweden)

Anthony J Angwin

Full Text Available Event-related potentials (ERPs were recorded to investigate lexical ambiguity resolution during sentence processing in 16 people with Parkinson's disease (PD and 16 healthy controls. Sentences were presented word-by-word on computer screen, and participants were required to decide if a subsequent target word was related to the meaning of the sentence. The task consisted of related, unrelated and ambiguous trials. For the ambiguous trials, the sentence ended with an ambiguous word and the target was related to one of the meanings of that word, but not the one captured by the sentence context (e.g., 'He dug with the spade', Target 'ACE'. Both groups demonstrated slower reaction times and lower accuracy for the ambiguous condition relative to the unrelated condition, however accuracy was impacted by the ambiguous condition to a larger extent in the PD group. These results suggested that PD patients experience increased difficulties with contextual ambiguity resolution. The ERP results did not reflect increased ambiguity resolution difficulties in PD, as a similar N400 effect was evident for the unrelated and ambiguous condition in both groups. However, the magnitude of the N400 for these conditions was correlated with a measure of inhibition in the PD group, but not the control group. The ERP results suggest that semantic processing may be more compromised in PD patients with increased response inhibition deficits.

Rayleigh wave group velocity and shear wave velocity structure in the San Francisco Bay region from ambient noise tomography

Science.gov (United States)

Li, Peng; Thurber, Clifford

2018-06-01

We derive new Rayleigh wave group velocity models and a 3-D shear wave velocity model of the upper crust in the San Francisco Bay region using an adaptive grid ambient noise tomography algorithm and 6 months of continuous seismic data from 174 seismic stations from multiple networks. The resolution of the group velocity models is 0.1°-0.2° for short periods (˜3 s) and 0.3°-0.4° for long periods (˜10 s). The new shear wave velocity model of the upper crust reveals a number of important structures. We find distinct velocity contrasts at the Golden Gate segment of the San Andreas Fault, the West Napa Fault, central part of the Hayward Fault and southern part of the Calaveras Fault. Low shear wave velocities are mainly located in Tertiary and Quaternary basins, for instance, La Honda Basin, Livermore Valley and the western and eastern edges of Santa Clara Valley. Low shear wave velocities are also observed at the Sonoma volcanic field. Areas of high shear wave velocity include the Santa Lucia Range, the Gabilan Range and Ben Lomond Plutons, and the Diablo Range, where Franciscan Complex or Silinian rocks are exposed.

Theory-Based Evaluation Meets Ambiguity: The Role of Janus Variables

Science.gov (United States)

Dahler-Larsen, Peter

2018-01-01

As theory-based evaluation (TBE) engages in situations where multiple stakeholders help develop complex program theory about dynamic phenomena in politically contested settings, it becomes difficult to develop and use program theory without ambiguity. The purpose of this article is to explore ambiguity as a fruitful perspective that helps TBE face…

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

Science.gov (United States)

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

2013-01-01

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

Spectral Ambiguity of Allan Variance

Science.gov (United States)

Greenhall, C. A.

1996-01-01

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

Anomalous group velocity at the high energy range of real 3D photonic nanostructures

Science.gov (United States)

Botey, Muriel; Martorell, Jordi; Lozano, Gabriel; Míguez, Hernán; Dorado, Luis A.; Depine, Ricardo A.

2010-05-01

We perform a theoretical study on the group velocity for finite thin artificial opal slabs made of a reduced number of layers in the spectral range where the light wavelength is on the order of the lattice parameter. The vector KKR method including extinction allows us to evaluate the finite-size effects on light propagation in the ΓL and ΓX directions of fcc close-packed opal films made of dielectric spheres. The group is index determined from the phase delay introduced by the structure to the forwardly transmitted electric field. We show that for certain frequencies, light propagation can either be superluminal -positive or negative- or approach zero depending on the crystal size and absorption. Such anomalous behavior can be attributed to the finite character of the structure and provides confirmation of recently emerged experimental results.

Ambiguity in Speaking Chemistry and Other STEM Content: Educational Implications

Science.gov (United States)

Isaacson, Mick D.; Michaels, Michelle

2015-01-01

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

Electrodermal responses during appetitive conditioning are sensitive to contingency instruction ambiguity.

Science.gov (United States)

van den Akker, Karolien; Nederkoorn, Chantal; Jansen, Anita

2017-08-01

Studies on human appetitive conditioning using food rewards can benefit from including psychophysiological outcome measures. The present study tested whether the skin conductance response can function as a measure of differential responding in an appetitive conditioning paradigm including an acquisition and extinction phase, and examined which time window during a trial is most sensitive to conditioning effects. As a secondary aim, the effects of ambiguous vs. non-ambiguous contingency instructions on conditioned responses (skin conductance responses, US expectancies, chocolate desires, and CS evaluations) were assessed. Results indicated differential skin conductance responses in an anticipatory time window and during unexpected omission of the US in early extinction. Interestingly however, anticipatory responses were only found for participants who received ambiguous contingency instructions - possibly indicating a call for additional processing resources in response to the ambiguous CS+. Further, ambiguous instructions slowed the extinction of US expectancies but did not influence chocolate desires and CS evaluations. It is concluded that skin conductance can function as a sensitive measure of differential responding in appetitive conditioning, though its sensitivity might depend on the specific task context. Copyright © 2017 Elsevier B.V. All rights reserved.

Logic without unique readability - a study of semantic and syntactic ambiguity

DEFF Research Database (Denmark)

Bentzen, Martin Mose

One of the main reasons for introducing a formal language is to remove ambiguity, the possibility of assigning several meanings to a linguistic expression. Typically, this is achieved through ensuring unique readability of formulas by using brackets (or another convention, such as Polish notation...... not hold true universally. Whereas e.g. scope ambiguities in natural languages have been studied extensively, ambiguous formal languages have not been the focus of in depth research. Here, we lift the assumption of unique readability by omitting the brackets from propositional logic, making it possible...... to formally distinguish between syntactic and semantic ambiguity. A valuation then amounts to a semantic disambiguation, and rather than a unique valuation (truth value), there is a set of valuations corresponding to ways a formula could have been constructed. We show what happens to familiar concepts...

A deterministic and stochastic velocity model for the Salton Trough/Basin and Range transition zone and constraints on magmatism during rifting

Science.gov (United States)

Larkin, Steven P.; Levander, Alan; Okaya, David; Goff, John A.

1996-12-01

As a high resolution addition to the 1992 Pacific to Arizona Crustal Experiment (PACE), a 45-km-long deep crustal seismic reflection profile was acquired across the Chocolate Mountains in southeastern California to illuminate crustal structure in the transition between the Salton Trough and the Basin and Range province. The complex seismic data are analyzed for both large-scale (deterministic) and fine-scale (stochastic) crustal features. A low-fold near-offset common-midpoint (CMP) stacked section shows the northeastward lateral extent of a high-velocity lower crustal body which is centered beneath the Salton Trough. Off-end shots record a high-amplitude diffraction from the point where the high velocity lower crust pinches out at the Moho. Above the high-velocity lower crust, moderate-amplitude reflections occur at midcrustal levels. These reflections display the coherency and frequency characteristics of reflections backscattered from a heterogeneous velocity field, which we model as horizontal intrusions with a von Kármán (fractal) distribution. The effects of upper crustal scattering are included by combining the mapped surface geology and laboratory measurements of exposed rocks within the Chocolate Mountains to reproduce the upper crustal velocity heterogeneity in our crustal velocity model. Viscoelastic finite difference simulations indicate that the volume of mafic material within the reflective zone necessary to produce the observed backscatter is about 5%. The presence of wavelength-scale heterogeneity within the near-surface, upper, and middle crust also produces a 0.5-s-thick zone of discontinuous reflections from a crust-mantle interface which is actually a first-order discontinuity.

The real potential continuous ambiguity for 90 MeV Li ions

International Nuclear Information System (INIS)

Cook, J.; Barnwell, J.M.; Clarke, N.M.; Griffiths, R.J.

1980-01-01

The features of discrete and continuous ambiguities in the real phenomenological optical potential are clarified. The continuous ambiguity in the real potential for the scattering of 90 MeV 6 Li and 7 Li ions from 27 Al is investigated. For 6 Li the ambiguity is of Igo (Phys. Rev. Lett.; 1: 72 (1958) and Phys. Rev.; 115: 1665 (1959)) type but for 7 Li it is of Vrsup(n) = constant type. The implications of this are that 7 Li is less strongly absorbed than 6 Li. (author)

The impact of ambiguous economic news on uncertainty and consumer confidence

NARCIS (Netherlands)

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

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

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

Science.gov (United States)

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. PsycINFO Database Record (c) 2013 APA, all rights reserved

Sadder but wiser : the effects of emotional states on ambiguity attitudes

NARCIS (Netherlands)

Baillon, A.; Koelinger, P.; Treffers, T.

“Many important decisions are made without precise information about the probabilities of the outcomes. In such situations, individual ambiguity attitudes influence decision making. The present study identifies emotions as a transient cause of ambiguity attitudes. We conducted two random-assignment,

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

Science.gov (United States)

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

2016-11-01

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

Psychophsyiological reactivity during uncertainty and ambiguity processing in high and low worriers.

Science.gov (United States)

Kirschner, Hans; Hilbert, Kevin; Hoyer, Jana; Lueken, Ulrike; Beesdo-Baum, Katja

2016-03-01

Intolerance of uncertainty (IU) has been linked to Generalized Anxiety Disorder (GAD), but studies experimentally manipulating uncertainty have mostly failed to find differences between GAD patients and controls, possible due to a lack of distinction between uncertainty and ambiguity. This study therefore investigated reactivity to ambiguity in addition to uncertainty in high worriers (HW) and low worriers (LW). We hypothesized an interpretation bias between the groups during ambiguity tasks, while uncertainty would facilitate threat processing of subsequent aversive stimuli. HW (N = 23) and LW (N = 23) completed a paradigm comprising the anticipation and perception of pictures with dangerous, safe, or ambiguous content. Anticipatory cues were certain (always correct information about the following picture) or uncertain (no information). Subjective ratings, reaction times and skin conductance responses (SCRs) were recorded. HW rated particularly ambiguous pictures as more aversive and showed longer reaction times to all picture conditions compared to LW. SCRs were also larger in HW compared to LW, particularly during uncertain but also safe anticipation. No group differences were observed during perception of stimuli. All participants were female. HW was used as subclinical phenotype of GAD. Intolerance of ambiguity seems to be related to individual differences in worry and possibly to the development of GAD. Threat-related interpretations differentiating HW and LW occurred particularly for ambiguous pictures but were not accompanied by increased autonomic arousal during the picture viewing. This disparity between subjective rating and arousal may be the result of worrying in response to intolerance of uncertainty, restraining physiological responses. Copyright © 2015 Elsevier Ltd. All rights reserved.

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

Science.gov (United States)

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.

Investigation of the equality constraint effect on the reduction of the rotational ambiguity in three-component system using a novel grid search method.

Science.gov (United States)

Beyramysoltan, Samira; Rajkó, Róbert; Abdollahi, Hamid

2013-08-12

The obtained results by soft modeling multivariate curve resolution methods often are not unique and are questionable because of rotational ambiguity. It means a range of feasible solutions equally fit experimental data and fulfill the constraints. Regarding to chemometric literature, a survey of useful constraints for the reduction of the rotational ambiguity is a big challenge for chemometrician. It is worth to study the effects of applying constraints on the reduction of rotational ambiguity, since it can help us to choose the useful constraints in order to impose in multivariate curve resolution methods for analyzing data sets. In this work, we have investigated the effect of equality constraint on decreasing of the rotational ambiguity. For calculation of all feasible solutions corresponding with known spectrum, a novel systematic grid search method based on Species-based Particle Swarm Optimization is proposed in a three-component system. Copyright © 2013 Elsevier B.V. All rights reserved.

A mixture approach to vagueness and ambiguity.

Directory of Open Access Journals (Sweden)

Steven Verheyen

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

POSTTRAUMATIC STRESS SYMPTOMS AND AVERSION TO AMBIGUOUS LOSSES IN COMBAT VETERANS.

Science.gov (United States)

Ruderman, Lital; Ehrlich, Daniel B; Roy, Alicia; Pietrzak, Robert H; Harpaz-Rotem, Ilan; Levy, Ifat

2016-07-01

Psychiatric symptoms typically cut across traditional diagnostic categories. In order to devise individually tailored treatments, there is a need to identify the basic mechanisms that underlie these symptoms. Behavioral economics provides a framework for studying these mechanisms at the behavioral level. Here, we utilized this framework to examine a widely ignored aspect of trauma-related symptomatology-individual uncertainty attitudes-in combat veterans with and without posttraumatic stress disorder (PTSD). Fifty-seven combat veterans, including 30 with PTSD and 27 without PTSD, completed a risk and ambiguity decision-making task that characterizes individual uncertainty attitudes, distinguishing between attitudes toward uncertain outcomes with known ("risk") and unknown ("ambiguity") probabilities, and between attitudes toward uncertain gains and uncertain losses. Participants' choices were used to estimate risk and ambiguity attitudes in the gain and loss domains. Veterans with PTSD were more averse to ambiguity, but not risk, compared to veterans without PTSD, when making choices between possible losses, but not gains. The degree of aversion was associated with anxious arousal (e.g., hypervigilance) symptoms, as well as with the degree of combat exposure. Moreover, ambiguity attitudes fully mediated the association between combat exposure and anxious arousal symptoms. These results provide a foundation for prospective studies of the causal association between ambiguity attitudes and trauma-related symptoms, as well as etiologic studies of the neural underpinnings of these behavioral outcomes. More generally, these results demonstrate the potential of neuroeconomic and behavioral economic techniques for devising objective and incentive-compatible diagnostic tools, and investigating the etiology of psychiatric disorders. © 2016 Wiley Periodicals, Inc.

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

Science.gov (United States)

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

2015-02-01

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

Review of Leading Approaches for Mitigating Hypersonic Vehicle Communications Blackout and a Method of Ceramic Particulate Injection Via Cathode Spot Arcs for Blackout Mitigation

Science.gov (United States)

Gillman, Eric D.; Foster, John E.; Blankson, Isaiah M.

2010-01-01

Vehicles flying at hypersonic velocities within the atmosphere become enveloped in a "plasma sheath" that prevents radio communication, telemetry, and most importantly, GPS signal reception for navigation. This radio "blackout" period has been a problem since the dawn of the manned space program and was an especially significant hindrance during the days of the Apollo missions. An appropriate mitigation method must allow for spacecraft to ground control and ground control to spacecraft communications through the reentry plasma sheath. Many mitigation techniques have been proposed, including but not limited to, aerodynamic shaping, magnetic windows, and liquid injection. The research performed on these mitigation techniques over the years will be reviewed and summarized, along with the advantages and obstacles that each technique will need to overcome to be practically implemented. A unique approach for mitigating the blackout communications problem is presented herein along with research results associated with this method. The novel method involves the injection of ceramic metal-oxide particulate into a simulated reentry plasma to quench the reentry plasma. Injection of the solid ceramic particulates is achieved by entrainment within induced, energetic cathode spot flows.

Wind scatterometry with improved ambiguity selection and rain modeling

Science.gov (United States)

Draper, David Willis

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

Maximum Likelihood Blood Velocity Estimator Incorporating Properties of Flow Physics

DEFF Research Database (Denmark)

Schlaikjer, Malene; Jensen, Jørgen Arendt

2004-01-01

)-data under investigation. The flow physic properties are exploited in the second term, as the range of velocity values investigated in the cross-correlation analysis are compared to the velocity estimates in the temporal and spatial neighborhood of the signal segment under investigation. The new estimator...... has been compared to the cross-correlation (CC) estimator and the previously developed maximum likelihood estimator (MLE). The results show that the CMLE can handle a larger velocity search range and is capable of estimating even low velocity levels from tissue motion. The CC and the MLE produce...... for the CC and the MLE. When the velocity search range is set to twice the limit of the CC and the MLE, the number of incorrect velocity estimates are 0, 19.1, and 7.2% for the CMLE, CC, and MLE, respectively. The ability to handle a larger search range and estimating low velocity levels was confirmed...

Conservation Reserve Program mitigates grassland loss in the lesser prairie-chicken range of Kansas

Science.gov (United States)

Haukos, David A.; Spencer, David; Hagen, Christian A.; Daniels, Melinda D.; Goodin, Doug

2017-01-01

Since the beginning of the 20th century, the overall occupied range of the lesser prairie-chicken (Tympanuchus pallidicinctus) has declined by 84% commensurate with population trends. Much of this decline has been attributed to the loss and fragmentation of native grasslands throughout the lesser prairie-chicken range. However, quantification of changes in land cover in the distribution of the lesser prairie-chicken is lacking. Our objectives were to (1) document changes in the areal extent and connectivity of grasslands in the identified lesser prairie-chicken range in Kansas, USA, (>60% of extant lesser prairie-chicken population) from the 1950s to 2013 using remotely sensed data and (2) assess the potential of the Conservation Reserve Program (U.S. Department of Agriculture Program converting cropland to permanent cover; CRP) to mitigate grassland loss. Digital land cover maps were generated on a decadal time step through spectral classification of LANDSAT images and visual analysis of aerial photographs (1950s and 1960s). Landscape composition and configuration were assessed using FRAGSTATS to compute a variety of landscape metrics measuring changes in the amount of grassland present as well as changes in the size and configuration of grassland patches. With the exception of a single regional portion of the range, nearly all of the grassland converted to cropland in the lesser prairie-chicken range of Kansas occurred prior to the 1950s. Prior to the implementation of CRP, the amount of grassland decreased 3.6% between the 1950s and 1985 from 18,455 km2 to 17,788 km2. Since 1985, the overall amount of grassland in the lesser prairie-chicken range has increased 11.9% to 19,898 km2 due to implementation of CRP, although the area of grassland decreased between 1994 and 2013 as CRP contracts were not renewed by landowners. Since 1986 grassland in Kansas became more connected and less fragmented in response to the CRP. While the CRP has been successful in

Conservation Reserve Program mitigates grassland loss in the lesser prairie-chicken range of Kansas

Directory of Open Access Journals (Sweden)

David Spencer

2017-01-01

Full Text Available Since the beginning of the 20th century, the overall occupied range of the lesser prairie-chicken (Tympanuchus pallidicinctus has declined by 84% commensurate with population trends. Much of this decline has been attributed to the loss and fragmentation of native grasslands throughout the lesser prairie-chicken range. However, quantification of changes in land cover in the distribution of the lesser prairie-chicken is lacking. Our objectives were to (1 document changes in the areal extent and connectivity of grasslands in the identified lesser prairie-chicken range in Kansas, USA, (>60% of extant lesser prairie-chicken population from the 1950s to 2013 using remotely sensed data and (2 assess the potential of the Conservation Reserve Program (U.S. Department of Agriculture Program converting cropland to permanent cover; CRP to mitigate grassland loss. Digital land cover maps were generated on a decadal time step through spectral classification of LANDSAT images and visual analysis of aerial photographs (1950s and 1960s. Landscape composition and configuration were assessed using FRAGSTATS to compute a variety of landscape metrics measuring changes in the amount of grassland present as well as changes in the size and configuration of grassland patches. With the exception of a single regional portion of the range, nearly all of the grassland converted to cropland in the lesser prairie-chicken range of Kansas occurred prior to the 1950s. Prior to the implementation of CRP, the amount of grassland decreased 3.6% between the 1950s and 1985 from 18,455 km2 to 17,788 km2. Since 1985, the overall amount of grassland in the lesser prairie-chicken range has increased 11.9% to 19,898 km2 due to implementation of CRP, although the area of grassland decreased between 1994 and 2013 as CRP contracts were not renewed by landowners. Since 1986 grassland in Kansas became more connected and less fragmented in response to the CRP. While the CRP has been successful

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

Science.gov (United States)

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. (c) 2015 APA, all rights reserved).

Soliton microcomb range measurement

Science.gov (United States)

Suh, Myoung-Gyun; Vahala, Kerry J.

2018-02-01

Laser-based range measurement systems are important in many application areas, including autonomous vehicles, robotics, manufacturing, formation flying of satellites, and basic science. Coherent laser ranging systems using dual-frequency combs provide an unprecedented combination of long range, high precision, and fast update rate. We report dual-comb distance measurement using chip-based soliton microcombs. A single pump laser was used to generate dual-frequency combs within a single microresonator as counterpropagating solitons. We demonstrated time-of-flight measurement with 200-nanometer precision at an averaging time of 500 milliseconds within a range ambiguity of 16 millimeters. Measurements at distances up to 25 meters with much lower precision were also performed. Our chip-based source is an important step toward miniature dual-comb laser ranging systems that are suitable for photonic integration.

Mitigating reentry radio blackout by using a traveling magnetic field

Directory of Open Access Journals (Sweden)

Hui Zhou

2017-10-01

Full Text Available A hypersonic flight or a reentry vehicle is surrounded by a plasma layer that prevents electromagnetic wave transmission, which results in radio blackout. The magnetic-window method is considered a promising means to mitigate reentry communication blackout. However, the real application of this method is limited because of the need for strong magnetic fields. To reduce the required magnetic field strength, a novel method that applies a traveling magnetic field (TMF is proposed in this study. A mathematical model based on magneto-hydrodynamic theory is adopted to analyze the effect of TMF on plasma. The mitigating effects of the TMF on the blackout of typical frequency bands, including L-, S-, and C-bands, are demonstrated. Results indicate that a significant reduction of plasma density occurs in the magnetic-window region by applying a TMF, and the reduction ratio is positively correlated with the velocity of the TMF. The required traveling velocities for eliminating the blackout of the Global Positioning System (GPS and the typical telemetry system are also discussed. Compared with the constant magnetic-window method, the TMF method needs lower magnetic field strength and is easier to realize in the engineering field.

Mitigating reentry radio blackout by using a traveling magnetic field

Science.gov (United States)

Zhou, Hui; Li, Xiaoping; Xie, Kai; Liu, Yanming; Yu, Yuanyuan

2017-10-01

A hypersonic flight or a reentry vehicle is surrounded by a plasma layer that prevents electromagnetic wave transmission, which results in radio blackout. The magnetic-window method is considered a promising means to mitigate reentry communication blackout. However, the real application of this method is limited because of the need for strong magnetic fields. To reduce the required magnetic field strength, a novel method that applies a traveling magnetic field (TMF) is proposed in this study. A mathematical model based on magneto-hydrodynamic theory is adopted to analyze the effect of TMF on plasma. The mitigating effects of the TMF on the blackout of typical frequency bands, including L-, S-, and C-bands, are demonstrated. Results indicate that a significant reduction of plasma density occurs in the magnetic-window region by applying a TMF, and the reduction ratio is positively correlated with the velocity of the TMF. The required traveling velocities for eliminating the blackout of the Global Positioning System (GPS) and the typical telemetry system are also discussed. Compared with the constant magnetic-window method, the TMF method needs lower magnetic field strength and is easier to realize in the engineering field.

Motion discrimination under uncertainty and ambiguity.

NARCIS (Netherlands)

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

2011-01-01

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

A New Block Processing Algorithm of LLL for Fast High-dimension Ambiguity Resolution

Directory of Open Access Journals (Sweden)

LIU Wanke

2016-02-01

Full Text Available Due to high dimension and precision for the ambiguity vector under GNSS observations of multi-frequency and multi-system, a major problem to limit computational efficiency of ambiguity resolution is the longer reduction time when using conventional LLL algorithm. To address this problem, it is proposed a new block processing algorithm of LLL by analyzing the relationship between the reduction time and the dimensions and precision of ambiguity. The new algorithm reduces the reduction time to improve computational efficiency of ambiguity resolution, which is based on block processing ambiguity variance-covariance matrix that decreased the dimensions of single reduction matrix. It is validated that the new algorithm with two groups of measured data. The results show that the computing efficiency of the new algorithm increased by 65.2% and 60.2% respectively compared with that of LLL algorithm when choosing a reasonable number of blocks.

Auditory motion capturing ambiguous visual motion

Directory of Open Access Journals (Sweden)

Arjen eAlink

2012-01-01

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

Design Procedure Enhanced with Numerical Modeling to Mitigate River-Bank Erosion

Directory of Open Access Journals (Sweden)

Elhakeem Mohamed

2016-01-01

Full Text Available In this study, the 2D Finite Element Surface Water Modeling System (FESWMS is used to design barb structures to mitigate river bank erosion in a stream reach located on the Raccoon River near Adel, Iowa, USA just upstream of the US Highway Bridge 169. FESWMS is used also to access the barbs effect on the study reach. The model results showed that the proposed barb structures successfully reduced the flow velocity along the outside bank and increased the velocity in the center of the stream, thereby successfully increased the conveyance towards the core of the river. The estimated velocities values along the river-banks where the barbs exist were within the recommended values for channel stability design. Thus, the barb structures were able to reduce the erosion along the bankline.

Velocity distribution of fragments of catastrophic impacts

Science.gov (United States)

Takagi, Yasuhiko; Kato, Manabu; Mizutani, Hitoshi

1992-01-01

Three dimensional velocities of fragments produced by laboratory impact experiments were measured for basalts and pyrophyllites. The velocity distribution of fragments obtained shows that the velocity range of the major fragments is rather narrow, at most within a factor of 3 and that no clear dependence of velocity on the fragment mass is observed. The NonDimensional Impact Stress (NDIS) defined by Mizutani et al. (1990) is found to be an appropriate scaling parameter to describe the overall fragment velocity as well as the antipodal velocity.

Relationship Between the Range of Motion and Isometric Strength of Elbow and Shoulder Joints and Ball Velocity in Women Team Handball Players.

Science.gov (United States)

Schwesig, René; Hermassi, Souhail; Wagner, Herbert; Fischer, David; Fieseler, Georg; Molitor, Thomas; Delank, Karl-Stefan

2016-12-01

Schwesig, R, Hermassi, S, Wagner, H, Fischer, D, Fieseler, G, Molitor, T, and Delank, K-S. Relationship between the range of motion and isometric strength of elbow and shoulder joints and ball velocity in women team handball players. J Strength Cond Res 30(12): 3428-3435, 2016-The aims of this study were to investigate relationships between isometric strength and range of motion (ROM) of shoulder and elbow joints and compare 2 different team handball throwing techniques in women team handball. Twenty highly experienced women team handball players (age: 20.7 ± 2.9 years; body mass: 68.4 ± 6.0 kg; and height: 1.74 ± 0.06 m) participated in this study. The isometric strength (hand-held dynamometer) and ROM (goniometer) of shoulder and elbow joints were measured at the beginning of the preseasonal training. After clinical examination, the subjects performed 3 standing throws with run-up (10 m) and 3 jump throws over a hurdle (0.20 m). The mean ball velocity was calculated from 3 attempts and measured using a radar gun. The results showed that the ball velocity of the standing throw with run-up (vST) was significantly higher than that of the jump throw (vJT) (25.5 ± 1.56 vs. 23.2 ± 1.31 m·s; p handball players.

Mitigation of defocusing by statics and near-surface velocity errors by interferometric least-squares migration

KAUST Repository

Sinha, Mrinal

2015-08-19

We propose an interferometric least-squares migration method that can significantly reduce migration artifacts due to statics and errors in the near-surface velocity model. We first choose a reference reflector whose topography is well known from the, e.g., well logs. Reflections from this reference layer are correlated with the traces associated with reflections from deeper interfaces to get crosscorrelograms. These crosscorrelograms are then migrated using interferometric least-squares migration (ILSM). In this way statics and velocity errors at the near surface are largely eliminated for the examples in our paper.

More than visual literacy: art and the enhancement of tolerance for ambiguity and empathy.

Science.gov (United States)

Bentwich, Miriam Ethel; Gilbey, Peter

2017-11-10

Comfort with ambiguity, mostly associated with the acceptance of multiple meanings, is a core characteristic of successful clinicians. Yet past studies indicate that medical students and junior physicians feel uncomfortable with ambiguity. Visual Thinking Strategies (VTS) is a pedagogic approach involving discussions of art works and deciphering the different possible meanings entailed in them. However, the contribution of art to the possible enhancement of the tolerance for ambiguity among medical students has not yet been adequately investigated. We aimed to offer a novel perspective on the effect of art, as it is experienced through VTS, on medical students' tolerance of ambiguity and its possible relation to empathy. Quantitative method utilizing a short survey administered after an interactive VTS session conducted within mandatory medical humanities course for first-year medical students. The intervention consisted of a 90-min session in the form of a combined lecture and interactive discussions about art images. The VTS session and survey were filled by 67 students in two consecutive rounds of first-year students. 67% of the respondents thought that the intervention contributed to their acceptance of multiple possible meanings, 52% thought their visual observation ability was enhanced and 34% thought that their ability to feel the sufferings of other was being enhanced. Statistically significant moderate-to-high correlations were found between the contribution to ambiguity tolerance and contribution to empathy (0.528-0.744; p ≤ 0.01). Art may contribute especially to the development of medical students' tolerance of ambiguity, also related to the enhancement of empathy. The potential contribution of visual art works used in VTS to the enhancement of tolerance for ambiguity and empathy is explained based on relevant literature regarding the embeddedness of ambiguity within art works, coupled with reference to John Dewey's theory of learning. Given the

Propagation of the Semidiurnal Internal Tide: Phase Velocity Versus Group Velocity

Science.gov (United States)

Zhao, Zhongxiang

2017-12-01

The superposition of two waves of slightly different wavelengths has long been used to illustrate the distinction between phase velocity and group velocity. The first-mode M2 and S2 internal tides exemplify such a two-wave model in the natural ocean. The M2 and S2 tidal frequencies are 1.932 and 2 cycles per day, respectively, and their superposition forms a spring-neap cycle in the semidiurnal band. The spring-neap cycle acts like a wave, with its frequency, wave number, and phase being the differences of the M2 and S2 internal tides. The spring-neap cycle and energy of the semidiurnal internal tide propagate at the group velocity. Long-range propagation of M2 and S2 internal tides in the North Pacific is observed by satellite altimetry. Along a 3,400 km beam spanning 24°-54°N, the M2 and S2 travel times are 10.9 and 11.2 days, respectively. For comparison, it takes the spring-neap cycle 21.1 days to travel over this distance. Spatial maps of the M2 phase velocity, the S2 phase velocity, and the group velocity are determined from phase gradients of the corresponding satellite observed internal tide fields. The observed phase and group velocities agree with theoretical values estimated using the World Ocean Atlas 2013 annual-mean ocean stratification.

Analysis of photosynthate translocation velocity and measurement of weighted average velocity in transporting pathway of crops

International Nuclear Information System (INIS)

Ge Cailin; Luo Shishi; Gong Jian; Zhang Hao; Ma Fei

1996-08-01

The translocation profile pattern of 14 C-photosynthate along the transporting pathway in crops were monitored by pulse-labelling a mature leaf with 14 CO 2 . The progressive spreading of translocation profile pattern along the sheath or stem indicates that the translocation of photosynthate along the sheath or stem proceed with a range of velocities rather than with just a single velocity. The method for measuring the weighted average velocity of photosynthate translocation along the sheath or stem was established in living crops. The weighted average velocity and the maximum velocity of photosynthate translocation along the sheath in rice and maize were measured actually. (4 figs., 3 tabs.)

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

Science.gov (United States)

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.

Size doesn't really matter: ambiguity aversion in Ellsberg urns with few balls.

Science.gov (United States)

Pulford, Briony D; Colman, Andrew M

2008-01-01

When attempting to draw a ball of a specified color either from an urn containing 50 red balls and 50 black balls or from an urn containing an unknown ratio of 100 red and black balls, a majority of decision makers prefer the known-risk urn, and this ambiguity aversion effect violates expected utility theory. In an experimental investigation of the effect of urn size on ambiguity aversion, 149 participants showed similar levels of aversion when choosing from urns containing 2, 10, or 100 balls. The occurrence of a substantial and significant ambiguity aversion effect even in the smallest urn suggests that influential theoretical interpretations of ambiguity aversion may need to be reconsidered.

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

Science.gov (United States)

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…

Aggregating imprecise or conflicting beliefs: An experimental investigation using modern ambiguity theories

NARCIS (Netherlands)

A. Baillon (Aurélien); L. Cabantous (Laure); P.P. Wakker (Peter)

2012-01-01

textabstractTwo experiments show that violations of expected utility due to ambiguity, found in general decision experiments, also affect belief aggregation. Hence we use modern ambiguity theories to analyze belief aggregation, thus obtaining more refined and empirically more valid results than

ROLE CONFLICT AND ROLE AMBIGUITY ON LOCAL GOVERNMENT INTERNAL AUDITORS: THE DETERMINANT AND IMPACTS

Directory of Open Access Journals (Sweden)

Agil Novriansa

2016-01-01

Full Text Available The bureaucratic reform at the local government level in Indonesia that was instituted in 2012 has turned local government internal auditors into an important part of government governance systems. The role of local government internal auditors has been expanded to include not only the area of audit oversight, but also the areas of anti-corruption-related and consulting activities. These fundamental changes may potentially induce role conflict and role ambiguity among internal auditors. The objective of this study is to examine empirically the determinants and consequences of role conflict and role ambiguity among local government internal auditors. More specifically, this study attempts to examine the extent to which formalization determines role conflict and role ambiguity; it further tests the impact of role conflict and role ambiguity on commitment to independence and job performance. Questionnaires were distributed to 248 local government internal auditors from 12 Regional Inspectorates in the provinces of Yogyakarta, South Sumatra, and East Java. A total of 176 responses were received, and 124 useable responses from the 176 responses were analysed to test the hypotheses. Using Structural Equation Modelling-Partial Least Square the results show that: formalization is negatively related to role conflict and role ambiguity; role ambiguity has a negative impact on commitment to independence; role conflict has a positive impact on job performance; and role ambiguity has a negative impact on job performance. These findings serve as important external validity evidence on the phenomena associated with role conflict and role ambiguity that occur in the public sector, especially among internal auditors at local government institutions.

Collective cell migration without proliferation: density determines cell velocity and wave velocity

Science.gov (United States)

Tlili, Sham; Gauquelin, Estelle; Li, Brigitte; Cardoso, Olivier; Ladoux, Benoît; Delanoë-Ayari, Hélène; Graner, François

2018-05-01

Collective cell migration contributes to embryogenesis, wound healing and tumour metastasis. Cell monolayer migration experiments help in understanding what determines the movement of cells far from the leading edge. Inhibiting cell proliferation limits cell density increase and prevents jamming; we observe long-duration migration and quantify space-time characteristics of the velocity profile over large length scales and time scales. Velocity waves propagate backwards and their frequency depends only on cell density at the moving front. Both cell average velocity and wave velocity increase linearly with the cell effective radius regardless of the distance to the front. Inhibiting lamellipodia decreases cell velocity while waves either disappear or have a lower frequency. Our model combines conservation laws, monolayer mechanical properties and a phenomenological coupling between strain and polarity: advancing cells pull on their followers, which then become polarized. With reasonable values of parameters, this model agrees with several of our experimental observations. Together, our experiments and model disantangle the respective contributions of active velocity and of proliferation in monolayer migration, explain how cells maintain their polarity far from the moving front, and highlight the importance of strain-polarity coupling and density in long-range information propagation.

The role of ambiguity and discrepancy in the early phases of innovation

DEFF Research Database (Denmark)

Laursen, Linda Nhu; Tollestrup, Christian H. T.

2015-01-01

Innovation literature mainly focuses on eliminating ambiguity and discrepancy from the early phases of innovation. This study questions this implicit assumption, as it may provide an oversimplified view on, how to attain proficiency. Instead of narrowly focusing on reducing ambiguity and discrepa...

More is not always better: coping with ambiguity in natural resources management

NARCIS (Netherlands)

Brugnach, M.; Dewulf, A.; Henriksen, H.J.; Keur, van der P.

2011-01-01

Coping with ambiguities in natural resources management has become unavoidable. Ambiguity is a distinct type of uncertainty that results from the simultaneous presence of multiple valid, and sometimes conflicting, ways of framing a problem. As such, it reflects discrepancies in meanings and

More is not always better: Coping with ambiguity in natural resources management

NARCIS (Netherlands)

Brugnach, Marcela Fabiana; De Wulf, A.; Henriksen, H.J.; van der Keur, P.

2011-01-01

Coping with ambiguities in natural resources management has become unavoidable. Ambiguity is a distinct type of uncertainty that results from the simultaneous presence of multiple valid, and sometimes conflicting, ways of framing a problem. As such, it reflects discrepancies in meanings and

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

Science.gov (United States)

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. PsycINFO Database Record (c) 2010 APA, all rights reserved.

The electrochemistry of IGSCC mitigation

International Nuclear Information System (INIS)

Macdonald, D.D.

2002-01-01

A brief review is presented of the electrochemical mitigation of intergranular stress corrosion cracking (IGSCC) in watercooled reactor heat transport circuit structural materials. Electrochemical control and mitigation is possible because of the existence of a critical potential for intergranular stress corrosion cracking and due to the feasibility of modifying the environment to displace the corrosion potential to a value that is more negative than the critical value. However, even in cases where the corrosion potential cannot be displaced sufficiently in the negative direction to become more negative than the critical potential, considerable advantage is accrued, because of the roughly exponential dependence of the crack growth rate on potential. The most important parameters in affecting electrochemical control over the corrosion potential and crack growth rate are the kinetic parameters (exchange current densities and Tafel constants) for the redox reactions involving the principal radiolysis products of water (O 2 , H 2 H 2 O 2 ), external solution composition (concentrations of O 2 , H 2 O 2 , and H 2 ), flow velocity, and the conductivity of the bulk environment. The kinetic parameters for the redox reactions essentially determine the charge transfer impedance of the steel surface, which is shown to be one of the key parameters in affecting the magnitude of the coupling current and hence the crack growth rate. The exchange current densities, in particular, are amenable to control by catalysis or inhibition, with the result that surface modification techniques are highly effective in controlling and mitigating intergranular stress corrosion cracking in reactor coolant circuit materials. (orig.)

A bi-annular-gap magnetorheological energy absorber for shock and vibration mitigation

Science.gov (United States)

Bai, Xian-Xu; Wereley, Norman M.; Choi, Young-Tai; Wang, Dai-Hua

2012-04-01

For semi-active shock and vibration mitigation systems using magnetorheological energy absorbers (MREAs), the minimization of the field-off damper force of the MREA at high speed is of particular significance because the damper force due to the viscous damping at high speed becomes too excessive and thus the controllable dynamic force range that is defined by the ratio of the field-on damper force to the field-off damper force is significantly reduced. In this paper, a bi-annular-gap MREA with an inner-set permanent magnet is proposed to decrease the field-off damper force at high speed while keeping appropriate dynamic force range for improving shock and vibration mitigation performance. In the bi-annular-gap MREA, two concentric annular gaps are configured in parallel so as to decrease the baseline damper force and both magnetic activation methods using the electromagnetic coil winding and the permanent magnet are used to keep holding appropriate magnetic intensity in these two concentric annular gaps in the consideration of failure of the electric power supply. An initial field-on damper force is produced by the magnetic field bias generated from the inner-set permanent magnet. The initial damper force of the MREA can be increased (or decreased) through applying positive (or negative) current to the electromagnetic coil winding inside the bi-annular-gap MREA. After establishing the analytical damper force model of the bi-annular-gap MREA using a Bingham-plastic nonlinear fluid model, the principle and magnetic properties of the MREA are analytically validated and analyzed via electromagnetic finite element analysis (FEA). The performance of the bi-annular-gap MREA is also theoretically compared with that of a traditional single-annular- gap MREA with the constraints of an identical volume by the performance matrix, such as the damper force, dynamic force range, and Bingham number with respect to different excitation velocities.

Ego depletion in visual perception: Ego-depleted viewers experience less ambiguous figure reversal.

Science.gov (United States)

Wimmer, Marina C; Stirk, Steven; Hancock, Peter J B

2017-10-01

This study examined the effects of ego depletion on ambiguous figure perception. Adults (N = 315) received an ego depletion task and were subsequently tested on their inhibitory control abilities that were indexed by the Stroop task (Experiment 1) and their ability to perceive both interpretations of ambiguous figures that was indexed by reversal (Experiment 2). Ego depletion had a very small effect on reducing inhibitory control (Cohen's d = .15) (Experiment 1). Ego-depleted participants had a tendency to take longer to respond in Stroop trials. In Experiment 2, ego depletion had small to medium effects on the experience of reversal. Ego-depleted viewers tended to take longer to reverse ambiguous figures (duration to first reversal) when naïve of the ambiguity and experienced less reversal both when naïve and informed of the ambiguity. Together, findings suggest that ego depletion has small effects on inhibitory control and small to medium effects on bottom-up and top-down perceptual processes. The depletion of cognitive resources can reduce our visual perceptual experience.

Task Characteristics and Work Engagement: Exploring Effects of Role Ambiguity and ICT Presenteeism

Directory of Open Access Journals (Sweden)

Sang-Hoon Lee

2017-10-01

Full Text Available In order to secure organizational sustainability in a rapidly changing environment, it is necessary to implement a decentralized and flexible work environment. In such work environments, normally individuals are provided with autonomy and independence in performing tasks, thus allowing them to further engage in their given work. This study investigated task antecedents of work engagement, and further explored the process of how task characteristics affect work engagement. It focused on examining the mediating effect of role ambiguity on the task characteristics-work engagement relationship and the moderating effect of information and communication technology (ICT presenteeism on the task characteristics–role ambiguity relationship through multiple regression analyses and a bootstrapping procedure on survey data collected from 202 South Korean employees. It found that task interdependence and autonomy were negatively associated with role ambiguity. Of the two task characteristics, only task interdependence had a negative relationship with role ambiguity, and this relationship was significantly moderated by ICT presenteeism such that the negative association between task interdependence and role ambiguity was more pronounced when ICT presenteeism was high than when it was low.

Ambiguities of theoretical parameters and CP or T violation in neutrino factories

International Nuclear Information System (INIS)

Koike, Masafumi; Ota, Toshihiko; Sato, Joe

2002-01-01

We study the sensitivity to the CP- or T-violation search in the presence of ambiguities of the theoretical parameters. Three generations of neutrinos are considered. The parameters whose ambiguities are considered are the differences of the squared masses, the mixing angles, and the density of matter. We first consider the statistics that are sensitive to the genuine CP-violation effect originating from the imaginary coupling. No ambiguity of the parameters is considered in this part. It is argued that the widely adopted usual statistics are not necessarily sensitive to the genuine CP-violation effect. Two statistics that are sensitive to the imaginary coupling are proposed. The qualitative difference between these statistics and the usual ones are discussed. Next we proceed to the case where the ambiguity of the parameters is present. The sensitivity of the CP-violation search is greatly spoiled when the baseline length is longer than about one thousand kilometers, which turns out to be due to the ambiguity of the matter effect. Thus the CP-violation search by use of CP conjugate channels turns out to require a low energy neutrino and short baseline length. It is also shown that such a loss of sensitivity is avoided by using T-conjugate oscillation channels

Role conflict, role ambiguity and job satisfaction: Perceptions of the Brazilian controllers

Directory of Open Access Journals (Sweden)

Marilu Nuñez Palomino

2016-06-01

Full Text Available ABSTRACT From early times to the present, accounting literature has recorded several situations involving role conflict and ambiguity that cause tension among controllers. The theoretical framework was comprised of the seminal work on Role Theory by Katz and Kahn (1970, and empirical evidence regarding the evolution of the role of controllers in the enterprises. In this study, we used the structural equations technique, which allowed for non-rejection of the two study hypotheses, thus providing evidence that role conflict and ambiguity adversely affect job satisfaction among Brazilian controllers. The sample was comprised of 114 controllers. An electronic questionnaire was used to collect the data, allowing information about the respondents to be captured, along with their perceptions regarding levels of role conflict and ambiguity and job satisfaction. For this, the tools developed by Rizzo, House, and Lirtzman (1970 were used, as well as the Job Satisfaction Index presented by Tarrant and Sabo (2010. The results indicated that Brazilian controllers perceive role conflict and role ambiguity while they perform their duties. Job satisfaction of the controllers isaffected more strongly by role ambiguity than by role conflict. However, despite perceiving these two tensions, executives are moderately satisfied with their current working conditions.

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

Science.gov (United States)

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

2014-06-26

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

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

Science.gov (United States)

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

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

Energy Technology Data Exchange (ETDEWEB)

Stark, R.H.

1977-05-01

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

Evaluation of force-velocity and power-velocity relationship of arm muscles.

Science.gov (United States)

Sreckovic, Sreten; Cuk, Ivan; Djuric, Sasa; Nedeljkovic, Aleksandar; Mirkov, Dragan; Jaric, Slobodan

2015-08-01

A number of recent studies have revealed an approximately linear force-velocity (F-V) and, consequently, a parabolic power-velocity (P-V) relationship of multi-joint tasks. However, the measurement characteristics of their parameters have been neglected, particularly those regarding arm muscles, which could be a problem for using the linear F-V model in both research and routine testing. Therefore, the aims of the present study were to evaluate the strength, shape, reliability, and concurrent validity of the F-V relationship of arm muscles. Twelve healthy participants performed maximum bench press throws against loads ranging from 20 to 70 % of their maximum strength, and linear regression model was applied on the obtained range of F and V data. One-repetition maximum bench press and medicine ball throw tests were also conducted. The observed individual F-V relationships were exceptionally strong (r = 0.96-0.99; all P stronger relationships. The reliability of parameters obtained from the linear F-V regressions proved to be mainly high (ICC > 0.80), while their concurrent validity regarding directly measured F, P, and V ranged from high (for maximum F) to medium-to-low (for maximum P and V). The findings add to the evidence that the linear F-V and, consequently, parabolic P-V models could be used to study the mechanical properties of muscular systems, as well as to design a relatively simple, reliable, and ecologically valid routine test of the muscle ability of force, power, and velocity production.

Consequences of Team Job Demands: Role Ambiguity Climate, Affective Engagement, and Extra-Role Performance.

Science.gov (United States)

Mañas, Miguel A; Díaz-Fúnez, Pedro; Pecino, Vicente; López-Liria, Remedios; Padilla, David; Aguilar-Parra, José M

2017-01-01

In the absence of clearly established procedures in the workplace, employees will experience a negative affective state. This situation influences their well-being and their intention to behave in ways that benefit the organization beyond their job demands. This impact is more relevant on teamwork where members share the perception of ambiguity through emotional contagion (role ambiguity climate). In the framework of the job demands-resources model, the present study analyzes how high levels of role ambiguity climate can have such an effect to reduce employee affective engagement. Over time it has been associated with negative results for the organization due to a lack of extra-role performance. The sample included 706 employees from a multinational company, who were divided into 11 work teams. In line with the formulated hypotheses, the results confirm the negative influence of the role ambiguity climate on extra-role performance, and the mediated effect of affective engagement in the relationship between the role ambiguity climate and extra-role performance. These findings indicate that the role ambiguity climate is related to the adequate or inadequate functioning of employees within a work context.

Consequences of Team Job Demands: Role Ambiguity Climate, Affective Engagement, and Extra-Role Performance

Science.gov (United States)

Mañas, Miguel A.; Díaz-Fúnez, Pedro; Pecino, Vicente; López-Liria, Remedios; Padilla, David; Aguilar-Parra, José M.

2018-01-01

In the absence of clearly established procedures in the workplace, employees will experience a negative affective state. This situation influences their well-being and their intention to behave in ways that benefit the organization beyond their job demands. This impact is more relevant on teamwork where members share the perception of ambiguity through emotional contagion (role ambiguity climate). In the framework of the job demands-resources model, the present study analyzes how high levels of role ambiguity climate can have such an effect to reduce employee affective engagement. Over time it has been associated with negative results for the organization due to a lack of extra-role performance. The sample included 706 employees from a multinational company, who were divided into 11 work teams. In line with the formulated hypotheses, the results confirm the negative influence of the role ambiguity climate on extra-role performance, and the mediated effect of affective engagement in the relationship between the role ambiguity climate and extra-role performance. These findings indicate that the role ambiguity climate is related to the adequate or inadequate functioning of employees within a work context. PMID:29375424

Consequences of Team Job Demands: Role Ambiguity Climate, Affective Engagement, and Extra-Role Performance

Directory of Open Access Journals (Sweden)

Miguel A. Mañas

2018-01-01

Full Text Available In the absence of clearly established procedures in the workplace, employees will experience a negative affective state. This situation influences their well-being and their intention to behave in ways that benefit the organization beyond their job demands. This impact is more relevant on teamwork where members share the perception of ambiguity through emotional contagion (role ambiguity climate. In the framework of the job demands-resources model, the present study analyzes how high levels of role ambiguity climate can have such an effect to reduce employee affective engagement. Over time it has been associated with negative results for the organization due to a lack of extra-role performance. The sample included 706 employees from a multinational company, who were divided into 11 work teams. In line with the formulated hypotheses, the results confirm the negative influence of the role ambiguity climate on extra-role performance, and the mediated effect of affective engagement in the relationship between the role ambiguity climate and extra-role performance. These findings indicate that the role ambiguity climate is related to the adequate or inadequate functioning of employees within a work context.

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

Science.gov (United States)

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

2012-06-01

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

Wave-equation Migration Velocity Analysis Using Plane-wave Common Image Gathers

KAUST Repository

Guo, Bowen

2017-06-01

Wave-equation migration velocity analysis (WEMVA) based on subsurface-offset, angle domain or time-lag common image gathers (CIGs) requires significant computational and memory resources because it computes higher dimensional migration images in the extended image domain. To mitigate this problem, a WEMVA method using plane-wave CIGs is presented. Plane-wave CIGs reduce the computational cost and memory storage because they are directly calculated from prestack plane-wave migration, and the number of plane waves is often much smaller than the number of shots. In the case of an inaccurate migration velocity, the moveout of plane-wave CIGs is automatically picked by a semblance analysis method, which is then linked to the migration velocity update by a connective function. Numerical tests on two synthetic datasets and a field dataset validate the efficiency and effectiveness of this method.

Measuring the ambiguity tolerance of medical students: a cross-sectional study from the first to sixth academic years.

Science.gov (United States)

Weissenstein, Anne; Ligges, Sandra; Brouwer, Britta; Marschall, Bernhard; Friederichs, Hendrik

2014-01-09

Tolerance of ambiguity, or the extent to which ambiguous situations are perceived as desirable, is an important component of the attitudes and behaviors of medical students. However, few studies have compared this trait across the years of medical school. General practitioners are considered to have a higher ambiguity tolerance than specialists. We compared ambiguity tolerance between general practitioners and medical students. We designed a cross-sectional study to evaluate the ambiguity tolerance of 622 medical students in the first to sixth academic years. We compared this with the ambiguity tolerance of 30 general practitioners. We used the inventory for measuring ambiguity tolerance (IMA) developed by Reis (1997), which includes three measures of ambiguity tolerance: openness to new experiences, social conflicts, and perception of insoluble problems. We obtained a total of 564 complete data sets (return rate 90.1%) from medical students and 29 questionnaires (return rate 96.7%) from general practitioners. In relation to the reference groups defined by Reis (1997), medical students had poor ambiguity tolerance on all three scales. No differences were found between those in the first and the sixth academic years, although we did observe gender-specific differences in ambiguity tolerance. We found no differences in ambiguity tolerance between general practitioners and medical students. The ambiguity tolerance of the students that we assessed was below average, and appeared to be stable throughout the course of their studies. In contrast to our expectations, the general practitioners did not have a higher level of ambiguity tolerance than the students did.

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

Science.gov (United States)

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…

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

Science.gov (United States)

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…

Acute stress affects risk taking but not ambiguity aversion.

Science.gov (United States)

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

2014-01-01

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

Space-frequency analysis and reduction of potential field ambiguity

Directory of Open Access Journals (Sweden)

A. Rapolla

1997-06-01

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

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

Science.gov (United States)

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. © 2014 Family Process Institute.

Cross-linguistic scope ambiguity: When two systems meet

Directory of Open Access Journals (Sweden)

Gregory Scontras

2017-04-01

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

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

Science.gov (United States)

Duncan, Lauren E; Peterson, Bill E

2014-01-01

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

Ambiguity assessment of small-angle scattering curves from monodisperse systems.

Science.gov (United States)

Petoukhov, Maxim V; Svergun, Dmitri I

2015-05-01

A novel approach is presented for an a priori assessment of the ambiguity associated with spherically averaged single-particle scattering. The approach is of broad interest to the structural biology community, allowing the rapid and model-independent assessment of the inherent non-uniqueness of three-dimensional shape reconstruction from scattering experiments on solutions of biological macromolecules. One-dimensional scattering curves recorded from monodisperse systems are nowadays routinely utilized to generate low-resolution particle shapes, but the potential ambiguity of such reconstructions remains a major issue. At present, the (non)uniqueness can only be assessed by a posteriori comparison and averaging of repetitive Monte Carlo-based shape-determination runs. The new a priori ambiguity measure is based on the number of distinct shape categories compatible with a given data set. For this purpose, a comprehensive library of over 14,000 shape topologies has been generated containing up to seven beads closely packed on a hexagonal grid. The computed scattering curves rescaled to keep only the shape topology rather than the overall size information provide a `scattering map' of this set of shapes. For a given scattering data set, one rapidly obtains the number of neighbours in the map and the associated shape topologies such that in addition to providing a quantitative ambiguity measure the algorithm may also serve as an alternative shape-analysis tool. The approach has been validated in model calculations on geometrical bodies and its usefulness is further demonstrated on a number of experimental X-ray scattering data sets from proteins in solution. A quantitative ambiguity score (a-score) is introduced to provide immediate and convenient guidance to the user on the uniqueness of the ab initio shape reconstruction from the given data set.

Climate Velocity Can Inform Conservation in a Warming World.

Science.gov (United States)

Brito-Morales, Isaac; García Molinos, Jorge; Schoeman, David S; Burrows, Michael T; Poloczanska, Elvira S; Brown, Christopher J; Ferrier, Simon; Harwood, Tom D; Klein, Carissa J; McDonald-Madden, Eve; Moore, Pippa J; Pandolfi, John M; Watson, James E M; Wenger, Amelia S; Richardson, Anthony J

2018-06-01

Climate change is shifting the ranges of species. Simple predictive metrics of range shifts such as climate velocity, that do not require extensive knowledge or data on individual species, could help to guide conservation. We review research on climate velocity, describing the theory underpinning the concept and its assumptions. We highlight how climate velocity has already been applied in conservation-related research, including climate residence time, climate refugia, endemism, historic and projected range shifts, exposure to climate change, and climate connectivity. Finally, we discuss ways to enhance the use of climate velocity in conservation through tailoring it to be more biologically meaningful, informing design of protected areas, conserving ocean biodiversity in 3D, and informing conservation actions. Copyright © 2018 Elsevier Ltd. All rights reserved.

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

Science.gov (United States)

Nguyen, Tien Manh

1989-01-01

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

Field Testing of an In-well Point Velocity Probe for the Rapid Characterization of Groundwater Velocity

Science.gov (United States)

Osorno, T.; Devlin, J. F.

2017-12-01

Reliable estimates of groundwater velocity is essential in order to best implement in-situ monitoring and remediation technologies. The In-well Point Velocity Probe (IWPVP) is an inexpensive, reusable tool developed for rapid measurement of groundwater velocity at the centimeter-scale in monitoring wells. IWPVP measurements of groundwater speed are based on a small-scale tracer test conducted as ambient groundwater passes through the well screen and the body of the probe. Horizontal flow direction can be determined from the difference in tracer mass passing detectors placed in four funnel-and-channel pathways through the probe, arranged in a cross pattern. The design viability of the IWPVP was confirmed using a two-dimensional numerical model in Comsol Multiphysics, followed by a series of laboratory tank experiments in which IWPVP measurements were calibrated to quantify seepage velocities in both fine and medium sand. Lab results showed that the IWPVP was capable of measuring the seepage velocity in less than 20 minutes per test, when the seepage velocity was in the range of 0.5 to 4.0 m/d. Further, the IWPVP estimated the groundwater speed with a precision of ± 7%, and an accuracy of ± 14%, on average. The horizontal flow direction was determined with an accuracy of ± 15°, on average. Recently, a pilot field test of the IWPVP was conducted in the Borden aquifer, C.F.B. Borden, Ontario, Canada. A total of approximately 44 IWPVP tests were conducted within two 2-inch groundwater monitoring wells comprising a 5 ft. section of #8 commercial well screen. Again, all tests were completed in under 20 minutes. The velocities estimated from IWPVP data were compared to 21 Point Velocity Probe (PVP) tests, as well as Darcy-based estimates of groundwater velocity. Preliminary data analysis shows strong agreement between the IWPVP and PVP estimates of groundwater velocity. Further, both the IWPVP and PVP estimates of groundwater velocity appear to be reasonable when

Fast simulated annealing inversion of surface waves on pavement using phase-velocity spectra

Science.gov (United States)

Ryden, N.; Park, C.B.

2006-01-01

The conventional inversion of surface waves depends on modal identification of measured dispersion curves, which can be ambiguous. It is possible to avoid mode-number identification and extraction by inverting the complete phase-velocity spectrum obtained from a multichannel record. We use the fast simulated annealing (FSA) global search algorithm to minimize the difference between the measured phase-velocity spectrum and that calculated from a theoretical layer model, including the field setup geometry. Results show that this algorithm can help one avoid getting trapped in local minima while searching for the best-matching layer model. The entire procedure is demonstrated on synthetic and field data for asphalt pavement. The viscoelastic properties of the top asphalt layer are taken into account, and the inverted asphalt stiffness as a function of frequency compares well with laboratory tests on core samples. The thickness and shear-wave velocity of the deeper embedded layers are resolved within 10% deviation from those values measured separately during pavement construction. The proposed method may be equally applicable to normal soil site investigation and in the field of ultrasonic testing of materials. ?? 2006 Society of Exploration Geophysicists.

Three-frequency BDS precise point positioning ambiguity resolution based on raw observables

Science.gov (United States)

Li, Pan; Zhang, Xiaohong; Ge, Maorong; Schuh, Harald

2018-02-01

All BeiDou navigation satellite system (BDS) satellites are transmitting signals on three frequencies, which brings new opportunity and challenges for high-accuracy precise point positioning (PPP) with ambiguity resolution (AR). This paper proposes an effective uncalibrated phase delay (UPD) estimation and AR strategy which is based on a raw PPP model. First, triple-frequency raw PPP models are developed. The observation model and stochastic model are designed and extended to accommodate the third frequency. Then, the UPD is parameterized in raw frequency form while estimating with the high-precision and low-noise integer linear combination of float ambiguity which are derived by ambiguity decorrelation. Third, with UPD corrected, the LAMBDA method is used for resolving full or partial ambiguities which can be fixed. This method can be easily and flexibly extended for dual-, triple- or even more frequency. To verify the effectiveness and performance of triple-frequency PPP AR, tests with real BDS data from 90 stations lasting for 21 days were performed in static mode. Data were processed with three strategies: BDS triple-frequency ambiguity-float PPP, BDS triple-frequency PPP with dual-frequency (B1/B2) and three-frequency AR, respectively. Numerous experiment results showed that compared with the ambiguity-float solution, the performance in terms of convergence time and positioning biases can be significantly improved by AR. Among three groups of solutions, the triple-frequency PPP AR achieved the best performance. Compared with dual-frequency AR, additional the third frequency could apparently improve the position estimations during the initialization phase and under constraint environments when the dual-frequency PPP AR is limited by few satellite numbers.

AMBIGUITY OF LOCI DURING HLA-TYPING ON SSO TECHNOLOGY AND ATTEMPT TO RESOLVE THEM

Directory of Open Access Journals (Sweden)

M. A. Loginova

2010-01-01

Full Text Available Sequence specific oligonucleotides typing was used to identify human leukocyte antigen (HLA-A, B, DRB1 alleles from 705 recruited volunteers with Volga Federal District for unrelated hematopoietic stem cell registry and 155 of their number at locus HLA-C. 48 samples cannot be entered into the database because of ambiguities in the identification of allelic loci on HLA-class I – HLA-A, HLA-B. To resolution of ambiguity use reagents kits AlleleSEQR HLA Sequencing, which allowed to reveal the ambiguity of the locus HLA-A, 44% of cases, the loci HLA-B and HLA-C – 40% of cases. Application software HARPs Finder showed the possibility of resolution of all identified allelic ambiguities (with the exception of types of ambiguity – A*03/A*32 or A*74:13/A*32:04 and A*01/A*11 or A*36:04/A*11 with the addition of basic kits AlleleSEQR HLA Sequencing reagents kit Al- leleSEQR HARPs. 

Diffeomorphisms, Anomalies and the Fefferman-Graham Ambiguity

International Nuclear Information System (INIS)

Schwimmer, A.; Theisen, S.

2000-01-01

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

Portfolio Management with Stochastic Interest Rates and Inflation Ambiguity

DEFF Research Database (Denmark)

Munk, Claus; Rubtsov, Alexey Vladimirovich

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

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

NARCIS (Netherlands)

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

2012-01-01

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

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

NARCIS (Netherlands)

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

2012-01-01

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

Quantum-mechanical analysis of the VRsup(n) ambiguity in the optical model

International Nuclear Information System (INIS)

Shastry, C.S.

1982-01-01

Using analytical methods and without adopting numerical calculations or semiclassical arguments, it is shown that the well known VRsup(n), n is approximately equal to 2, parameter ambiguity in the neutron-nucleus optical potential can be attributed to the closeness of the Woods-Saxon potential to the corresponding square well inside the nucleus. This parameter ambiguity is absent in individual partial waves but is more apparent in the differential cross section. The analysis is generalised to the proton-nucleus optical model. The present method clearly pinpoints the mathematical origin of the VRsup(n) ambiguity which is difficult to deduce by purely numerical methods. (author)

A motion-based integer ambiguity resolution method for attitude determination using the global positioning system (GPS)

International Nuclear Information System (INIS)

Wang, Bo; Deng, Zhihong; Wang, Shunting; Fu, Mengyin

2010-01-01

Loss of the satellite signal and noise disturbance will cause cycle slips to occur in the carrier phase observation of the attitude determination system using the global positioning system (GPS), especially in the dynamic situation. Therefore, in order to reject the error by cycle slips, the integer ambiguity should be re-computed. A motion model-based Kalman predictor is used for the ambiguity re-computation in dynamic applications. This method utilizes the correct observation of the last step to predict the current ambiguities. With the baseline length as a constraint to reject invalid values, we can solve the current integer ambiguity and the attitude angles, by substituting the obtained ambiguities into the constrained LAMBDA method. Experimental results demonstrate that the proposed method is more efficient in the dynamic situation, which takes less time to obtain new fixed ambiguities with a higher mean success rate

Ionization waves of arbitrary velocity driven by a flying focus

Science.gov (United States)

Palastro, J. P.; Turnbull, D.; Bahk, S.-W.; Follett, R. K.; Shaw, J. L.; Haberberger, D.; Bromage, J.; Froula, D. H.

2018-03-01

A chirped laser pulse focused by a chromatic lens exhibits a dynamic, or flying, focus in which the trajectory of the peak intensity decouples from the group velocity. In a medium, the flying focus can trigger an ionization front that follows this trajectory. By adjusting the chirp, the ionization front can be made to travel at an arbitrary velocity along the optical axis. We present analytical calculations and simulations describing the propagation of the flying focus pulse, the self-similar form of its intensity profile, and ionization wave formation. The ability to control the speed of the ionization wave and, in conjunction, mitigate plasma refraction has the potential to advance several laser-based applications, including Raman amplification, photon acceleration, high-order-harmonic generation, and THz generation.

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

International Nuclear Information System (INIS)

Muthukumar, B.

2015-01-01

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

Ambiguous diagnosis, futile treatments and temporary recovery ...

African Journals Online (AJOL)

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

On the Impact of L2 Speech Rhythm on Syntactic Ambiguity Resolution

Science.gov (United States)

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

2015-01-01

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

The Ethics of Ambiguity: Rethinking the Role and Importance of Uncertainty in Medical Education and Practice.

Science.gov (United States)

Domen, Ronald E

2016-01-01

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

The interaction of patient race, provider bias, and clinical ambiguity on pain management decisions.

Science.gov (United States)

Hirsh, Adam T; Hollingshead, Nicole A; Ashburn-Nardo, Leslie; Kroenke, Kurt

2015-06-01

Although racial disparities in pain care are widely reported, much remains to be known about the role of provider and contextual factors. We used computer-simulated patients to examine the influence of patient race, provider racial bias, and clinical ambiguity on pain decisions. One hundred twenty-nine medical residents/fellows made assessment (pain intensity) and treatment (opioid and nonopioid analgesics) decisions for 12 virtual patients with acute pain. Race (black/white) and clinical ambiguity (high/low) were manipulated across vignettes. Participants completed the Implicit Association Test and feeling thermometers, which assess implicit and explicit racial biases, respectively. Individual- and group-level analyses indicated that race and ambiguity had an interactive effect on providers' decisions, such that decisions varied as a function of ambiguity for white but not for black patients. Individual differences across providers were observed for the effect of race and ambiguity on decisions; however, providers' implicit and explicit biases did not account for this variability. These data highlight the complexity of racial disparities and suggest that differences in care between white and black patients are, in part, attributable to the nature (ie, ambiguity) of the clinical scenario. The current study suggests that interventions to reduce disparities should differentially target patient, provider, and contextual factors. This study examined the unique and collective influence of patient race, provider racial bias, and clinical ambiguity on providers' pain management decisions. These results could inform the development of interventions aimed at reducing disparities and improving pain care. Copyright © 2015 American Pain Society. Published by Elsevier Inc. All rights reserved.

Urban Green Infrastructure as a tool for urban heat mitigation

NARCIS (Netherlands)

Saaroni, H.; Amorim, J.H.; Hiemstra, J.A.; Pearlmutter, D.

2018-01-01

The combined trends of urban heat island intensification and global warming are focusing attention on greening of cities as a tool for urban heat mitigation. Our study examines the range of research approaches and findings regarding the role of urban green infrastructure (UGI) in mitigating urban

Absence of the Gribov ambiguity in a special algebraic gauge

Directory of Open Access Journals (Sweden)

Raval Haresh

2016-01-01

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

Ambiguity and risk measures in the lab and students’ real-life borrowing behavior

NARCIS (Netherlands)

Fairley, Kim; Weitzel, Utz

This study analyzes the external validity of experimentally elicited ambiguity aversion, likelihood insensitivity and risk aversion on real-life decision-making in the field of student loans. Our main finding is that ambiguity aversion, likelihood insensitivity and risk aversion are not related to

An ambiguous relationship

DEFF Research Database (Denmark)

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

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

Micro-Doppler Ambiguity Resolution for Wideband Terahertz Radar Using Intra-Pulse Interference.

Science.gov (United States)

Yang, Qi; Qin, Yuliang; Deng, Bin; Wang, Hongqiang; You, Peng

2017-04-29

Micro-Doppler, induced by micro-motion of targets, is an important characteristic of target recognition once extracted via parameter estimation methods. However, micro-Doppler is usually too significant to result in ambiguity in the terahertz band because of its relatively high carrier frequency. Thus, a micro-Doppler ambiguity resolution method for wideband terahertz radar using intra-pulse interference is proposed in this paper. The micro-Doppler can be reduced several dozen times its true value to avoid ambiguity through intra-pulse interference processing. The effectiveness of this method is proved by experiments based on a 0.22 THz wideband radar system, and its high estimation precision and excellent noise immunity are verified by Monte Carlo simulation.

Drift velocity of free electrons in liquid argon

International Nuclear Information System (INIS)

Walkowiak, W.

2000-01-01

A measurement of the drift velocity of free electrons in liquid argon has been performed. Free electrons have been produced by photoelectric effect using laser light in a so-called 'laser chamber'. The results on the drift velocity v d are given as a function of the electric field strength in the range 0.5 kV/cm≤|E|≤12.6 kV/cm and the temperature in the range 87 K≤T≤94 K. A global parametrization of v d (|E|,T) has been fitted to the data. A temperature dependence of the electron drift velocity is observed, with a mean value of Δv d /(ΔT v d )=(-1.72±0.08)%/K in the range of 87-94 K

Impact of Decorrelation on Search Efficiency of Ambiguity Resolution

Directory of Open Access Journals (Sweden)

LU Liguo

2015-05-01

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

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

Science.gov (United States)

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

2016-10-01

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

In Command And Out Of Control: Leaders Developing Teams That Thrive In Chaos And Ambiguity

Science.gov (United States)

2016-05-26

In Command and Out of Control: Leaders Developing Teams that Thrive in Chaos and Ambiguity A Monograph by...TITLE AND SUBTITLE Sa. CONTRACT NUMBER In Command and Out of Control: Leaders Developing Teams that Thrive in Chaos and Ambiguity Sb. GRANT NUMBER...the chaos and ambiguity associated with war. Teams must provide the innovative and creative solutions formerly left to the individual leader. This

Comparison of turbulence mitigation algorithms

Science.gov (United States)

Kozacik, Stephen T.; Paolini, Aaron; Sherman, Ariel; Bonnett, James; Kelmelis, Eric

2017-07-01

When capturing imagery over long distances, atmospheric turbulence often degrades the data, especially when observation paths are close to the ground or in hot environments. These issues manifest as time-varying scintillation and warping effects that decrease the effective resolution of the sensor and reduce actionable intelligence. In recent years, several image processing approaches to turbulence mitigation have shown promise. Each of these algorithms has different computational requirements, usability demands, and degrees of independence from camera sensors. They also produce different degrees of enhancement when applied to turbulent imagery. Additionally, some of these algorithms are applicable to real-time operational scenarios while others may only be suitable for postprocessing workflows. EM Photonics has been developing image-processing-based turbulence mitigation technology since 2005. We will compare techniques from the literature with our commercially available, real-time, GPU-accelerated turbulence mitigation software. These comparisons will be made using real (not synthetic), experimentally obtained data for a variety of conditions, including varying optical hardware, imaging range, subjects, and turbulence conditions. Comparison metrics will include image quality, video latency, computational complexity, and potential for real-time operation. Additionally, we will present a technique for quantitatively comparing turbulence mitigation algorithms using real images of radial resolution targets.

Exploring Situated Ambiguity in Students' Entrepreneurial Learning

Science.gov (United States)

Kubberød, Elin; Pettersen, Inger Beate

2017-01-01

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

Mitigating tin whisker risks theory and practice

CERN Document Server

Handwerker, Carol A; Bath, Jasbir

2016-01-01

Discusses the growth mechanisms of tin whiskers and the effective mitigation strategies necessary to reduce whisker growth risks. This book covers key tin whisker topics, ranging from fundamental science to practical mitigation strategies. The text begins with a review of the characteristic properties of local microstructures around whisker and hillock grains to identify why these particular grains and locations become predisposed to forming whiskers and hillocks. The book discusses the basic properties of tin-based alloy finishes and the effects of various alloying elements on whisker formation, with a focus on potential mechanisms for whisker suppression or enhancement for each element. Tin whisker risk mitigation strategies for each tier of the supply chain for high reliability electronic systems are also described.

Hippocampal Processing of Ambiguity Enhances Fear Memory.

Science.gov (United States)

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

2017-02-01

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

Obstetricians' choice of cesarean delivery in ambiguous cases

DEFF Research Database (Denmark)

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

2009-01-01

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

Resolving combinatorial ambiguities in dilepton t t¯ event topologies with constrained M2 variables

Science.gov (United States)

Debnath, Dipsikha; Kim, Doojin; Kim, Jeong Han; Kong, Kyoungchul; Matchev, Konstantin T.

2017-10-01

We advocate the use of on-shell constrained M2 variables in order to mitigate the combinatorial problem in supersymmetry-like events with two invisible particles at the LHC. We show that in comparison to other approaches in the literature, the constrained M2 variables provide superior ansätze for the unmeasured invisible momenta and therefore can be usefully applied to discriminate combinatorial ambiguities. We illustrate our procedure with the example of dilepton t t ¯ events. We critically review the existing methods based on the Cambridge MT 2 variable and MAOS reconstruction of invisible momenta, and show that their algorithm can be simplified without loss of sensitivity, due to a perfect correlation between events with complex solutions for the invisible momenta and events exhibiting a kinematic endpoint violation. Then we demonstrate that the efficiency for selecting the correct partition is further improved by utilizing the M2 variables instead. Finally, we also consider the general case when the underlying mass spectrum is unknown, and no kinematic endpoint information is available.

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

Science.gov (United States)

Specht, Jennifer A

2013-01-01

This study explored the effect of mentoring on the levels of role conflict and role ambiguity experienced by novice nursing faculty related to their transitions into academe using a descriptive, comparative design. It also measured the relationship between the quality of mentoring experiences of novice nursing faculty and their levels of role conflict and role ambiguity using a correlational design. P. Benner's (1984) novice to expert model was utilized as a framework for successful role transition. J. R. Rizzo, R. J. House, and S. I. Lirtzman's (1970) role conflict and role ambiguity scale was used to measure the levels of role conflict and role ambiguity experienced by novice nursing faculty. Results indicate that participants (n = 224) who were mentored have significantly lower levels of role conflict (M = 3.57) and role ambiguity (M = 3.02) than those who were not mentored (M = 4.62 and M = 3.90, respectively). Also significant, the higher the participants' reported levels of quality of mentoring experiences were, the lower their levels of role conflict and role ambiguity were. The results of this study indicate that mentoring eases the transition of novice nursing faculty from practice into academe by decreasing the degree of role ambiguity and role conflict that they experience. © 2013.

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

Science.gov (United States)

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…

The tell-tale heart: physiological reactivity during resolution of ambiguity in youth anxiety.

Science.gov (United States)

Rozenman, Michelle; Vreeland, Allison; Iglesias, Marisela; Mendez, Melissa; Piacentini, John

2018-03-01

In the past decade, cognitive biases and physiological arousal have each been proposed as mechanisms through which paediatric anxiety develops and is maintained over time. Preliminary studies have found associations between anxious interpretations of ambiguity, physiological arousal, and avoidance, supporting theories that link cognition, psychophysiology, and behaviour. However, little is known about the relationship between youths' resolutions of ambiguity and physiological arousal during acute stress. Such information may have important clinical implications for use of verbal self-regulation strategies and cognitive restructuring during treatments for paediatric anxiety. In this brief report, we present findings suggesting that anxious, but not typically developing, youth select avoidant goals via non-threatening resolution of ambiguity during a stressor, and that this resolution of ambiguity is accompanied by physiological reactivity (heart rate, heart rate variability, and respiratory sinus arrhythmia). We propose future empirical research on the interplay between interpretation bias, psychophysiology, and child anxiety, as well as clinical implications.

Velocity-space sensitivity of neutron spectrometry measurements

DEFF Research Database (Denmark)

Jacobsen, Asger Schou; Salewski, Mirko; Eriksson, J.

2015-01-01

Neutron emission spectrometry (NES) measures the energies of neutrons produced in fusion reactions. Here we present velocity-space weight functions for NES and neutron yield measurements. Weight functions show the sensitivity as well as the accessible regions in velocity space for a given range...

Managing ambiguity in business. A holistic and innovative approach

Directory of Open Access Journals (Sweden)

Pop Oana

2017-07-01

Full Text Available This article will look at the hurdles of dealing with ambiguity and the wicked problems that organizations are struggling with, by providing key insights from a one year team coaching program that the author had the opportunity to deliver in a Romanian entrepreneurial organization. Based on the actual methods used and highlighting the findings and impact of the program, we will reflect on how ambiguity manifests in organizational settings and how wicked problems can be defined. The methods employed are within the range of complexity science and are holistic approaches to systemic interventions within organizations that combine soft systems methodology, paradoxical theory of change, complex responsive processes approach with important concepts from systems thinking such as archetypes, feedback loops and modeling. One of the key objectives of the article is to reunite different academic approaches and link them to a case study as a way of adding value to these approaches and to reiterate that research needs, to find its rightful place in the practitioners’ toolkit and have a more meaningful and direct impact on the real struggles that business is faced with. The author’s expertize in systemic interventions is based on extensive practitioner experience, having been trained and certified as a systemic coach and facilitator, and therefore draws upon the work of other skilled practitioners that support companies in finding successful ways to address complexity. Although the article can be easily put in the complexity science and systems thinking area of academic interest, the research questions and insights are intended to serve the learning and the evolution of organizations.

Resolving the sign ambiguity in ΔΓs with Bs→DsK

International Nuclear Information System (INIS)

Nandi, Soumitra; Nierste, Ulrich

2008-01-01

The analysis of tagged B s →J/ψφ decays determines the CP phase φ s in B s -B s mixing with a twofold ambiguity. The solutions differ in the sign of cosφ s which equals the sign of the width difference ΔΓ s among the two B s mass eigenstates. We point out that this ambiguity can be removed with the help of B s →D s K decays. We compare untagged and tagged strategies and find the tagged analysis more promising. The removal of the sign ambiguity in ΔΓ s can be done with relatively low statistics and could therefore be a target for the early stage of B s →D s K studies.

Financial Impact of Cancer Drug Wastage and Potential Cost Savings From Mitigation Strategies.

Science.gov (United States)

Leung, Caitlyn Y W; Cheung, Matthew C; Charbonneau, Lauren F; Prica, Anca; Ng, Pamela; Chan, Kelvin K W

2017-07-01

Cancer drug wastage occurs when a parenteral drug within a fixed vial is not administered fully to a patient. This study investigated the extent of drug wastage, the financial impact on the hospital budget, and the cost savings associated with current mitigation strategies. We conducted a cross-sectional study in three University of Toronto-affiliated hospitals of various sizes. We recorded the actual amount of drug wasted over a 2-week period while using current mitigation strategies. Single-dose vial cancer drugs with the highest wastage potentials were identified (14 drugs). To calculate the hypothetical drug wastage with no mitigation strategies, we determined how many vials of drugs would be needed to fill a single prescription. The total drug costs over the 2 weeks ranged from $50,257 to $716,983 in the three institutions. With existing mitigation strategies, the actual drug wastage over the 2 weeks ranged from $928 to $5,472, which was approximately 1% to 2% of the total drug costs. In the hypothetical model with no mitigation strategies implemented, the projected drug cost wastage would have been $11,232 to $149,131, which accounted for 16% to 18% of the total drug costs. As a result, the potential annual savings while using current mitigation strategies range from 15% to 17%. The financial impact of drug wastage is substantial. Mitigation strategies lead to substantial cost savings, with the opportunity to reinvest those savings. More research is needed to determine the appropriate methods to minimize risk to patients while using the cost-saving mitigation strategies.

The effect of fog on radionuclide deposition velocities

International Nuclear Information System (INIS)

Gibb, R.; Carson, P.; Thompson, W.

1997-01-01

Current nuclear power station release models do not evaluate deposition under foggy atmospheric conditions. Deposition velocities and scavenging coefficients of radioactive particles entrained in fog are presented for the Point Lepreau area of the Bay of Fundy coast. It is recommended to calculate deposition based on fog deposition velocities. The deposition velocities can be calculated from common meteorological data. The range of deposition velocities is approximately 1 - 100 cm/s. Fog deposition is surface roughness dependent with forests having larger deposition and deposition velocities than soil or grasses. (author)

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

Science.gov (United States)

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

Spin-selected velocity dependence of the associative ionization cross section in Na(3p)+Na(3p) collisions over the collision energy range from 2.4 to 290 meV

International Nuclear Information System (INIS)

Wang, M.; Keller, J.; Boulmer, J.; Weiner, J.

1987-01-01

We report new results on the direct measurement of the associative ionization (AI) cross section in collisions between velocity-selected and spin-oriented Na(3p) atoms. Improvements in the Doppler-shift velocity-selection technique permit measurement over an energy range spanning more than two orders of magnitude from subthermal to suprathermal regions. Spin orientations, parallel and antiparallel, enable determination of the excitation function (velocity dependence of the AI cross section) for the separate singlet and triplet manifolds of Na 2 states contributing to the AI process

The input ambiguity hypothesis and case blindness: an account of cross-linguistic and intra-linguistic differences in case errors.

Science.gov (United States)

Pelham, Sabra D

2011-03-01

English-acquiring children frequently make pronoun case errors, while German-acquiring children rarely do. Nonetheless, German-acquiring children frequently make article case errors. It is proposed that when child-directed speech contains a high percentage of case-ambiguous forms, case errors are common in child language; when percentages are low, case errors are rare. Input to English and German children was analyzed for percentage of case-ambiguous personal pronouns on adult tiers of corpora from 24 English-acquiring and 24 German-acquiring children. Also analyzed for German was the percentage of case-ambiguous articles. Case-ambiguous pronouns averaged 63·3% in English, compared with 7·6% in German. The percentage of case-ambiguous articles in German was 77·0%. These percentages align with the children's errors reported in the literature. It appears children may be sensitive to levels of ambiguity such that low ambiguity may aid error-free acquisition, while high ambiguity may blind children to case distinctions, resulting in errors.

An ambiguous relationship

DEFF Research Database (Denmark)

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

2013-01-01

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

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

International Nuclear Information System (INIS)

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

2007-01-01

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

Sealed bid auctions with ambiguity: an experimental study

Czech Academy of Sciences Publication Activity Database

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

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

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

Directory of Open Access Journals (Sweden)

Megan L Endres

2015-05-01

Full Text Available We conducted two research studies to address the malleability of 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.

Characteristic wave velocities in spherical electromagnetic cloaks

International Nuclear Information System (INIS)

Yaghjian, A D; Maci, S; Martini, E

2009-01-01

We investigate the characteristic wave velocities in spherical electromagnetic cloaks, namely, phase, ray, group and energy-transport velocities. After deriving explicit expressions for the phase and ray velocities (the latter defined as the phase velocity along the direction of the Poynting vector), special attention is given to the determination of group and energy-transport velocities, because a cursory application of conventional formulae for local group and energy-transport velocities can lead to a discrepancy between these velocities if the permittivity and permeability dyadics are not equal over a frequency range about the center frequency. In contrast, a general theorem can be proven from Maxwell's equations that the local group and energy-transport velocities are equal in linear, lossless, frequency dispersive, source-free bianisotropic material. This apparent paradox is explained by showing that the local fields of the spherical cloak uncouple into an E wave and an H wave, each with its own group and energy-transport velocities, and that the group and energy-transport velocities of either the E wave or the H wave are equal and thus satisfy the general theorem.

Brain states recognition during visual perception by means of artificial neural network in the different EEG frequency ranges

Science.gov (United States)

Musatov, V. Yu.; Runnova, A. E.; Andreev, A. V.; Zhuravlev, M. O.

2018-04-01

In the present paper, the possibility of classification by artificial neural networks of a certain architecture of ambiguous images is investigated using the example of the Necker cube from the experimentally obtained EEG recording data of several operators. The possibilities of artificial neural network classification of ambiguous images are investigated in the different frequency ranges of EEG recording signals.

COMPENSATION OF THE IONOSPHERIC EFFECTS ON SAR INTERFEROGRAM BASED ON RANGE SPLIT-SPECTRUM AND AZIMUTH OFFSET METHODS – A CASE STUDY OF YUSHU EARTHQUAKE

Directory of Open Access Journals (Sweden)

Y. F. He

2018-04-01

Full Text Available InSAR technique can measure the surface deformation with the accuracy of centimeter-level or even millimeter and therefore has been widely used in the deformation monitoring associated with earthquakes, volcanoes, and other geologic process. However, ionospheric irregularities can lead to the wavy fringes in the low frequency SAR interferograms, which disturb the actual information of geophysical processes and thus put severe limitations on ground deformations measurements. In this paper, an application of two common methods, the range split-spectrum and azimuth offset methods are exploited to estimate the contributions of the ionosphere, with the aim to correct ionospheric effects in interferograms. Based on the theoretical analysis and experiment, a performance analysis is conducted to evaluate the efficiency of these two methods. The result indicates that both methods can mitigate the ionospheric effect in SAR interferograms and the range split-spectrum method is more precise than the other one. However, it is also found that the range split-spectrum is easily contaminated by the noise, and the achievable accuracy of the azimuth offset method is limited by the ambiguous integral constant, especially with the strong azimuth variations induced by the ionosphere disturbance.

Influence of Velocity on Variability in Gait Kinematics

DEFF Research Database (Denmark)

Yang, Sylvia X M; Larsen, Peter K; Alkjær, Tine

2014-01-01

the concurrence of joint angles throughout a gait cycle at three different velocities (3.0, 4.5, 6.0 km/h). Six datasets at each velocity were collected from 16 men. A variability range VR throughout the gait cycle at each velocity for each joint angle for each person was calculated. The joint angles at each...... velocity were compared pairwise, and whenever this showed values within the VR of this velocity, the case was positive. By adding the positives throughout the gait cycle, phases with high and low concurrences were located; peak concurrence was observed at mid-stance phase. Striving for the same velocity...

Voluntary suppression of hyperthermia-induced hyperventilation mitigates the reduction in cerebral blood flow velocity during exercise in the heat.

Science.gov (United States)

Tsuji, Bun; Honda, Yasushi; Ikebe, Yusuke; Fujii, Naoto; Kondo, Narihiko; Nishiyasu, Takeshi

2015-04-15

Hyperthermia during prolonged exercise leads to hyperventilation, which can reduce arterial CO2 pressure (PaCO2 ) and, in turn, cerebral blood flow (CBF) and thermoregulatory response. We investigated 1) whether humans can voluntarily suppress hyperthermic hyperventilation during prolonged exercise and 2) the effects of voluntary breathing control on PaCO2 , CBF, sweating, and skin blood flow. Twelve male subjects performed two exercise trials at 50% of peak oxygen uptake in the heat (37°C, 50% relative humidity) for up to 60 min. Throughout the exercise, subjects breathed normally (normal-breathing trial) or they tried to control their minute ventilation (respiratory frequency was timed with a metronome, and target tidal volumes were displayed on a monitor) to the level reached after 5 min of exercise (controlled-breathing trial). Plotting ventilatory and cerebrovascular responses against esophageal temperature (Tes) showed that minute ventilation increased linearly with rising Tes during normal breathing, whereas controlled breathing attenuated the increased ventilation (increase in minute ventilation from the onset of controlled breathing: 7.4 vs. 1.6 l/min at +1.1°C Tes; P flow velocity (MCAV) with rising Tes, but controlled breathing attenuated those reductions (estimated PaCO2 -3.4 vs. -0.8 mmHg; MCAV -10.4 vs. -3.9 cm/s at +1.1°C Tes; P = 0.002 and 0.011, respectively). Controlled breathing had no significant effect on chest sweating or forearm vascular conductance (P = 0.67 and 0.91, respectively). Our results indicate that humans can voluntarily suppress hyperthermic hyperventilation during prolonged exercise, and this suppression mitigates changes in PaCO2 and CBF. Copyright © 2015 the American Physiological Society.

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

Science.gov (United States)

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

2015-12-01

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.

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

Science.gov (United States)

Cervoni, Annemarie; DeLucia-Waack, Janice

2011-01-01

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

An Approach to Predict Debris Flow Average Velocity

Directory of Open Access Journals (Sweden)

Chen Cao

2017-03-01

Full Text Available Debris flow is one of the major threats for the sustainability of environmental and social development. The velocity directly determines the impact on the vulnerability. This study focuses on an approach using radial basis function (RBF neural network and gravitational search algorithm (GSA for predicting debris flow velocity. A total of 50 debris flow events were investigated in the Jiangjia gully. These data were used for building the GSA-based RBF approach (GSA-RBF. Eighty percent (40 groups of the measured data were selected randomly as the training database. The other 20% (10 groups of data were used as testing data. Finally, the approach was applied to predict six debris flow gullies velocities in the Wudongde Dam site area, where environmental conditions were similar to the Jiangjia gully. The modified Dongchuan empirical equation and the pulled particle analysis of debris flow (PPA approach were used for comparison and validation. The results showed that: (i the GSA-RBF predicted debris flow velocity values are very close to the measured values, which performs better than those using RBF neural network alone; (ii the GSA-RBF results and the MDEE results are similar in the Jiangjia gully debris flow velocities prediction, and GSA-RBF performs better; (iii in the study area, the GSA-RBF results are validated reliable; and (iv we could consider more variables in predicting the debris flow velocity by using GSA-RBF on the basis of measured data in other areas, which is more applicable. Because the GSA-RBF approach was more accurate, both the numerical simulation and the empirical equation can be taken into consideration for constructing debris flow mitigation works. They could be complementary and verified for each other.

The ambiguous challenge of intranets

DEFF Research Database (Denmark)

Thommesen, Jacob

2003-01-01

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

From expert generalists to ambiguity masters: using ambiguity tolerance theory to redefine the practice of rural nurses.

Science.gov (United States)

Knight, Kaye; Kenny, Amanda; Endacott, Ruth

2016-06-01

To redefine the practice of rural nurses and describe a model that conceptualises the capabilities and characteristics required in the rural environment. The way in which the practice of rural nurses has been conceptualised is problematic. Definitions of rural nursing have been identified primarily through the functional context of rural health service delivery. The expert generalist term has provided a foundation theory for rural nurses with understandings informed by the scope of practice needed to meet service delivery requirements. However, authors exploring intrinsic characteristics of rural nurses have challenged this definition, as it does not adequately address the deeper, intangible complexities of practice required in the rural context. Despite this discourse, an alternative way to articulate the distinctive nature of rural nursing practice has eluded authors in Australia and internationally. A theoretical paper based on primary research. The development of the model was informed by the findings of a study that explored the nursing practice of managing telephone presentations in rural health services in Victoria, Australia. The study involved policy review from State and Federal governments, nursing and medical professional bodies, and five rural health services; semi-structured interviews with eight Directors of Nursing, seven registered nurses and focus group interviews with eight registered nurses. An ambiguity tolerance model drawn from corporate global entrepreneurship theory was adapted to explain the findings of the study. The adapted model presents capabilities and characteristics used by nurses to successfully manage the ambiguity of providing care in the rural context. Redefining the practice of rural nurses, through an adapted theory of ambiguity tolerance, highlights nursing characteristics and capabilities required in the rural context. This perspective offers new ways of thinking about the work of rural nurses, rural nurse policy, education

Effect of Changing Governance System: Result of Western Style Management Adoption to Japanese Culture of Ambiguity

Directory of Open Access Journals (Sweden)

Kohichiro Hotta

2009-02-01

Full Text Available This paper considers the difficulty of management style change through observation of the management style of Company-A, one of the biggest Japanese IT companies. Japanese economy grew after World War II until the early 1990's. During that era, Ba or SECI process worked in Japanese organizations very well. Further, there was an ambiguous culture in the background of such characteristics. Some kinds of ambiguity or adhocracy made positive effects for Japanese organizational activity, or ambiguity played an important role for Ba activity. There were nested Ba's in each organization with ambiguity. Ambiguous descriptions of roles for each organizational unit activated nested Ba's and generated hot groups. After the economic crisis, Company-A changed its governance and gave clear targets for each organizational unit and for each employee. This change gave new difficulty and diminishes its competence. The change denied the ambiguity in the organization but it was the basis of the competence. Adopting a new system of governance is not a simple activity. Systems must be adjusted to the culture of the organization. Company-A should study competitors in different cultures and adjust the methodology for its culture.

MIDAS robust trend estimator for accurate GPS station velocities without step detection

Science.gov (United States)

Blewitt, Geoffrey; Kreemer, Corné; Hammond, William C.; Gazeaux, Julien

2016-03-01

Automatic estimation of velocities from GPS coordinate time series is becoming required to cope with the exponentially increasing flood of available data, but problems detectable to the human eye are often overlooked. This motivates us to find an automatic and accurate estimator of trend that is resistant to common problems such as step discontinuities, outliers, seasonality, skewness, and heteroscedasticity. Developed here, Median Interannual Difference Adjusted for Skewness (MIDAS) is a variant of the Theil-Sen median trend estimator, for which the ordinary version is the median of slopes vij = (xj-xi)/(tj-ti) computed between all data pairs i > j. For normally distributed data, Theil-Sen and least squares trend estimates are statistically identical, but unlike least squares, Theil-Sen is resistant to undetected data problems. To mitigate both seasonality and step discontinuities, MIDAS selects data pairs separated by 1 year. This condition is relaxed for time series with gaps so that all data are used. Slopes from data pairs spanning a step function produce one-sided outliers that can bias the median. To reduce bias, MIDAS removes outliers and recomputes the median. MIDAS also computes a robust and realistic estimate of trend uncertainty. Statistical tests using GPS data in the rigid North American plate interior show ±0.23 mm/yr root-mean-square (RMS) accuracy in horizontal velocity. In blind tests using synthetic data, MIDAS velocities have an RMS accuracy of ±0.33 mm/yr horizontal, ±1.1 mm/yr up, with a 5th percentile range smaller than all 20 automatic estimators tested. Considering its general nature, MIDAS has the potential for broader application in the geosciences.

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

Science.gov (United States)

Haberkamp, Anke; Schmidt, Filipp

2015-09-01

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

Radon mitigation experience in difficult-to-mitigate schools

International Nuclear Information System (INIS)

Leovic, K.W.; Craig, A.B.

1990-01-01

Initial radon mitigation experience in schools has shown sub-slab depressurization (SSD) to be generally effective in reducing elevated levels of radon in schools that have a continuous layer of clean, coarse aggregate underneath the slab. However, mitigation experience is limited in schools without sub-slab aggregate and in schools with characteristics such as return-air ductwork underneath the slab or unducted return-air plenums in the drop ceiling that are open to the sub-slab area (via open tops of block walls). Mitigation of schools with utility tunnels and of schools constructed over crawl spaces is also limited. Three Maryland schools exhibiting some of the above characteristics are being researched to help understand the mechanisms that control radon entry and mitigation in schools where standard SSD systems are not effective. This paper discusses specific characteristics of potentially difficult-to-mitigate schools and, where applicable, details examples from the three Maryland schools

Flexible taxonomic assignment of ambiguous sequencing reads

Directory of Open Access Journals (Sweden)

Jansson Jesper

2011-01-01

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

Velocities of Auroral Coherent Echoes At 12 and 144 Mhz

Science.gov (United States)

Koustov, A. V.; Danskin, D. W.; Makarevitch, R. A.; Uspensky, M. V.; Janhunen, P.; Nishitani, N.; Nozawa, N.; Lester, M.; Milan, S.

Two Doppler coherent radar systems are currently working at Hankasalmi, Finland, the STARE and CUTLASS radars operating at 144 MHz and 12 MHz, respectively. The STARE beam 3 is nearly co-located with the CUTLASS beam 5 providing an opportunity for echo velocity comparison along the same direction but at significantly different radar frequencies. In this study we consider one event when STARE radar echoes are detected t the same ranges as CUTLASS radar echoes. The observations are complemented by EISCAT measurements of the ionospheric electric field and elec- tron density behavior at one range of 900 km. Two separate situations are studied; for the first one, CUTLASS observed F-region echoes (including the range of the EIS- CAT measurements) while for the second one CUTLASS observed E-region echoes. In both cases STARE E-region measurements were available. We show that F-region CUTLASS velocities agree well with the convection component along the CUTLASS radar beam while STARE velocities are sometimes smaller by a factor of 2-3. For the second case, STARE velocities are found to be either smaller or larger than CUTLASS velocities, depending on range. Plasma physics of E- and F-region irregularities is dis- cussed in attempt to explain inferred relationship between various velocities. Special attention is paid to ionospheric refraction that is important for the detection of 12-MHz echoes.

The Ambiguous Role of Constraints in Creativity

DEFF Research Database (Denmark)

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

2011-01-01

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

Seismic wave attenuation and velocity dispersion in UAE carbonates

Science.gov (United States)

Ogunsami, Abdulwaheed Remi

Interpreting the seismic property of fluids in hydrocarbon reservoirs at low frequency scale has been a cherished goal of petroleum geophysics research for decades. Lately, there has been tremendous interest in understanding attenuation as a result of fluid flow in porous media. Although interesting, the emerging experimental and theoretical information still remain ambiguous and are practically not utilized for reasons not too obscure. Attenuation is frequency dependent and hard to measure in the laboratory at low frequency. This thesis describes and reports the results of an experimental study of low frequency attenuation and velocity dispersion on a selected carbonate reservoir samples in the United Arab Emirates (UAE). For the low frequency measurements, stress-strain method was used to measure the moduli from which the velocity is derived. Attenuation was measured as the phase difference between the applied stress and the strain. For the ultrasonic component, the pulse propagation method was employed. To study the fluid effect especially at reservoir in situ conditions, the measurements were made dry and saturated with liquid butane and brine at differential pressures of up to 5000 psi with pore pressure held constant at 500 psi. Similarly to what has been documented in the literatures for sandstone, attenuation of the bulk compressibility mode dominates the losses in these dry and somewhat partially saturated carbonate samples with butane and brine. Overall, the observed attenuation cannot be simply said to be frequency dependent within this low seismic band. While attenuation seems to be practically constant in the low frequency band for sample 3H, such conclusion cannot be made for sample 7H. For the velocities, significant dispersion is observed and Gassmann generally fails to match the measured velocities. Only the squirt model fairly fits the velocities, but not at all pressures. Although the observed dispersion is larger than Biot's prediction, the fact

Wildlife mitigation program. Draft environmental impact statement

International Nuclear Information System (INIS)

1996-08-01

Bonneville Power Administration (BPA) is responsible for mitigating the loss of wildlife habitat caused by the development of the Federal Columbia River Power System. BPA accomplishes this mitigation by funding projects consistent with those recommended by the Northwest Power Planning Council (Council). The projects are submitted to the Council from Indian Tribes, state agencies, property owners, private conservation groups, and other Federal agencies. Future wildlife mitigation actions with potential environmental impacts are expected to include land acquisition and management, water rights acquisition and management, habitat restoration and enhancement, installation of watering devices, riparian fencing, and similar wildlife conservation actions. BPA needs to ensure that individual wildlife mitigation projects are planned and managed with appropriate consistency across projects, jurisdictions, and ecosystems, as well as across time. BPA proposes to standardize the planning and implementation of individual wildlife mitigation projects funded by BPA. Alternative 1 is the No Action alternative. Five standardizing alternatives are identified to represent the range of possible strategies, goals, and procedural requirements reasonably applicable to BPA-funded projects under a standardized approach to project planning and implementation. All action alternatives are based on a single project planning process designed to resolve site-specific issues in an ecosystem context and to adapt to changing conditions and information

Wildlife mitigation program final environmental impact statement

International Nuclear Information System (INIS)

1997-03-01

BPA is responsible for mitigating the loss of wildlife habitat caused by the development of the Federal Columbia River Power System. BPA accomplishes this mitigation by funding projects consistent with those recommended by the Northwest Power Planning Council (Council). The projects are submitted to the Council from Indian Tribes, state agencies, property owners, private conservation groups, and other Federal agencies. future wildlife mitigation actions with potential environmental impacts are expected to include land acquisition and management, water rights acquisition and management, habitat restoration and improvement, installation of watering devices, riparian fencing, and similar wildlife conservation actions. BPA needs to ensure that individual wildlife mitigation projects are planned and managed with appropriate consistency across projects, jurisdictions, and ecosystems, as well as across time. BPA proposes to standardize the planning and implementation of individual wildlife mitigation projects funded by BPA. Alternative 1 is the No Action alternative, i.e., not to establish program-wide standards. Five standardizing (action) alternatives are identified to represent the range of possible strategies, goals, and procedural requirements reasonably applicable to BPA-funded projects under a standardized approach to project planning and implementation. All action alternatives are based on a single project planning process designed to resolve site-specific issues in an ecosystem context and to adapt to changing conditions and information

Dealing with behavioral ambiguity in textual process descriptions

NARCIS (Netherlands)

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

2016-01-01

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

Sealed bid auctions with ambiguity: theory and experiments

Czech Academy of Sciences Publication Activity Database

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

2007-01-01

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

Wavelength-detuning cross-beam energy transfer mitigation scheme for direct drive: Modeling and evidence from National Ignition Facility implosions

Science.gov (United States)

Marozas, J. A.; Hohenberger, M.; Rosenberg, M. J.; Turnbull, D.; Collins, T. J. B.; Radha, P. B.; McKenty, P. W.; Zuegel, J. D.; Marshall, F. J.; Regan, S. P.; Sangster, T. C.; Seka, W.; Campbell, E. M.; Goncharov, V. N.; Bowers, M. W.; Di Nicola, J.-M. G.; Erbert, G.; MacGowan, B. J.; Pelz, L. J.; Moody, J.; Yang, S. T.

2018-05-01

Cross-beam energy transfer (CBET) results from two-beam energy exchange via seeded stimulated Brillouin scattering, which detrimentally reduces laser-energy absorption for direct-drive inertial confinement fusion. Consequently, ablation pressure and implosion velocity suffer from the decreased absorption, reducing target performance in both symmetric and polar direct drive. Additionally, CBET alters the time-resolved scattered-light spectra and redistributes absorbed and scattered-light-changing shell morphology and low-mode drive symmetry. Mitigating CBET is demonstrated in inertial confinement implosions at the National Ignition Facility by detuning the laser-source wavelengths (±2.3 Å UV) of the interacting beams. In polar direct drive, wavelength detuning was shown to increase the equatorial region velocity experimentally by 16% and to alter the in-flight shell morphology. These experimental observations are consistent with design predictions of radiation-hydrodynamic simulations that indicate a 10% increase in the average ablation pressure. These results indicate that wavelength detuning successfully mitigates CBET. Simulations predict that optimized phase plates and wavelength-detuning CBET mitigation utilizing the three-legged beam layout of the OMEGA Laser System significantly increase absorption and achieve >100-Gbar hot-spot pressures in symmetric direct drive.

Diabetic fetopathy associated with bilateral adrenal hyperplasia and ambiguous genitalia: a case report

Directory of Open Access Journals (Sweden)

Tantbirojn Patou

2008-07-01

Full Text Available Abstract Introduction Many fetal malformations can occur because of maternal diabetes. However, ambiguous genital organs have never been reported as an associated finding in the literature. This is the first report of associated ambiguous genital organ and bilateral adrenal hyperplasia in a case of diabetic fetopathy. Case presentation A 19-year-old Thai primigravida with familial history of diabetes mellitus (DM was diagnosed as having gestational DM type 2, based on 100 g oral glucose tolerance test, and was poorly controlled with insulin injections. Delayed targeted ultrasonography at 28 weeks gestation revealed multiple fetal anomalies. The woman underwent low transverse cesarean section at 30 weeks gestation due to preterm labor and transverse lie. The newborn with ambiguous genitalia was delivered but expired after birth. Autopsy findings revealed alobar holoprosencephaly, a prominent forehead, hypotelorism, an absent nose, absent bilateral ears, median cleft lip and palate, preaxial polydactyly of the right hand, accessory spleens, single umbilical artery, markedly enlarged adrenal glands and ambiguous external genitalia The subsequent fetal chromosomal study revealed 46,XX. Conclusion We describe a case of diabetic fetopathy with classic facial malformation and preaxial hallucal polydactyly which has been proposed as a marker of diabetic embryopathy. Bilateral adrenal hyperplasia with ambiguous genitalia, an uncommon associated anomaly, was also identified. It is controversial whether adrenal hyperplasia can be a novel feature of diabetic fetopathy or just a coincidental finding. Further observation and adequate investigation are needed in such cases.

Audiovisual Capture with Ambiguous Audiovisual Stimuli

Directory of Open Access Journals (Sweden)

Jean-Michel Hupé

2011-10-01

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

A few approaches to remove ambiguous factors in x-ray spectrum analysis

International Nuclear Information System (INIS)

Sera, K.; Futatsugawa, S.

1993-01-01

A few attempts have been done to reduce ambiguous factors in the analysis of complex x-ray spectra. Uncertainty in peak identification and separation due to overlapping of x-ray peaks can be reduced by taking into account the response function of x-ray peaks and by using peak functions including all the x-ray sub-lines in a x-ray series. Ambiguous factors due to discontinuity of backgrounds which is sometimes followed by huge peaks can be reduced by considering contributions from the pile-up, escape and tail functions. The problem of uncertainty in the background fitting in a region of low x-ray energy, where many peaks overlap each other and determination of the background function contains much difficulties and ambiguities, can be solved by using peak functions involving tails in place of Gaussians. (author)

Visual working memory contents bias ambiguous structure from motion perception.

Directory of Open Access Journals (Sweden)

Lisa Scocchia

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

Shear wave velocity structure of northern and North-Eastern Ethiopia

International Nuclear Information System (INIS)

Kebede, F.; Mammo, T.; Panza, G.F.; Vuan, A.; Costa, G.

1995-10-01

The non-linear inversion technique known as hedgehog is utilized to define the average crustal structure of North and North-Eastern Ethiopia. To accomplish the task a two dimensional frequency-time analysis is performed to obtain Rayleigh wave group velocity dispersion curves. Six earthquakes recorded by the broad-band digital seismograph installed at the Geophysical Observatory of Addis Ababa University are utilized. The crustal structure between the Gulf of Tadjura (western Gulf of Aden) and Addis Ababa crossing southern Afar (path I) can be approximated by a total thickness of about 22 km with average S-wave velocity in the range 2.3 - 3.9 km/s. The crust-mantle transition is poorly developed at greater depths and the shear wave velocity ranges from 4.0 km/s to 4.3 km/s. If the effect of the plateau part is taken into account the average total crustal thickness is found to be less than 18 km and the average S-wave velocity varies in the range 2.4 - 3.9 km/s. The low shear wave velocity under the Afar crust is consistent with the result of other geophysical studies. For path II, which passes through the border of the Western Ethiopian plateau, the average crustal structure is found to be approximated by a thickness of about 40 km and average S-wave velocity between 3.0 km/s and 3.9 km/s. The crust overlies a lithospheric mantle with a shear wave velocity in the range 4.1-4.4 km/s. (author). 37 refs, 11 figs, 4 tabs

Constant resolution of time-dependent Hartree--Fock phase ambiguity

International Nuclear Information System (INIS)

Lichtner, P.C.; Griffin, J.J.; Schultheis, H.; Schultheis, R.; Volkov, A.B.

1978-01-01

The customary time-dependent Hartree--Fock problem is shown to be ambiguous up to an arbitrary function of time additive to H/sub HF/, and, consequently, up to an arbitrary time-dependent phase for the solution, PHI(t). The ''constant'' (H)'' phase is proposed as the best resolution of this ambiguity. It leads to the following attractive features: (a) the time-dependent Hartree--Fock (TDHF) Hamiltonian, H/sub HF/, becomes a quantity whose expectation value is equal to the average energy and, hence, constant in time; (b) eigenstates described exactly by determinants, have time-dependent Hartree--Fock solutions identical with the exact time-dependent solutions; (c) among all possible TDHF solutions this choice minimizes the norm of the quantity (H--i dirac constant delta/delta t) operating on the ket PHI, and guarantees optimal time evolution over an infinitesimal period; (d) this choice corresponds both to the stationary value of the absolute difference between (H) and (i dirac constant delta/delta t) and simultaneously to its absolute minimal value with respect to choice of the time-dependent phase. The source of the ambiguity is discussed. It lies in the time-dependent generalization of the freedom to transform unitarily among the single-particle states of a determinant at the (physically irrelevant for stationary states) cost of altering only a factor of unit magnitude

Static vs Dynamic Auctions with Ambiguity Averse Bidders

NARCIS (Netherlands)

Carvalho, M.

2012-01-01

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

Resolution of ambiguities in cartoons as an illustration of the role of pragmatics in natural language understanding by computers

Energy Technology Data Exchange (ETDEWEB)

Mazlack, L.J.; Paz, N.M.

1983-01-01

Newspaper cartoons can graphically display the result of ambiguity in human speech; the result can be unexpected and funny. Likewise, computer analysis of natural language statements also needs to successfully resolve ambiguous situations. Computer techniques already developed use restricted world knowledge in resolving ambiguous language use. This paper illustrates how these techniques can be used in resolving ambiguous situations arising in cartoons. 8 references.

Paintball velocity as a function of distance traveled

Directory of Open Access Journals (Sweden)

Pat Chiarawongse

2008-06-01

Full Text Available The relationship between the distance a paintball travels through air and its velocity is investigated by firing a paintball into a ballistic pendulum from a range of distances. The motion of the pendulum was filmed and analyzed by using video analysis software. The velocity of the paintball on impact was calculated from the maximum horizontal displacement of the pendulum. It is shown that the velocity of a paintball decreases exponentially with distance traveled, as expected. The average muzzle velocity of the paint balls is found with an estimate of the drag coefficient.

Paintball velocity as a function of distance traveled

Directory of Open Access Journals (Sweden)

Pat Chiarawongse

2008-06-01

Full Text Available The relationship between the distance a paintball travels through air and its velocity is investigated by firing a paintball into a ballistic pendulum from a range of distances. The motion of the pendulum was filmed and analyzed by using video analysis software. The velocity of the paintball on impact was calculated from the maximum horizontal displacement of the pendulum. It is shown that the velocity of a paintball decreases exponentially with distance traveled, as expected. The average muzzle velocity of the paint balls is found with an estimate of the drag coefficient

Computational study of depth completion consistent with human bi-stable perception for ambiguous figures.

Science.gov (United States)

Mitsukura, Eiichi; Satoh, Shunji

2018-03-01

We propose a computational model that is consistent with human perception of depth in "ambiguous regions," in which no binocular disparity exists. Results obtained from our model reveal a new characteristic of depth perception. Random dot stereograms (RDS) are often used as examples because RDS provides sufficient disparity for depth calculation. A simple question confronts us: "How can we estimate the depth of a no-texture image region, such as one on white paper?" In such ambiguous regions, mathematical solutions related to binocular disparities are not unique or indefinite. We examine a mathematical description of depth completion that is consistent with human perception of depth for ambiguous regions. Using computer simulation, we demonstrate that resultant depth-maps qualitatively reproduce human depth perception of two kinds. The resultant depth maps produced using our model depend on the initial depth in the ambiguous region. Considering this dependence from psychological viewpoints, we conjecture that humans perceive completed surfaces that are affected by prior-stimuli corresponding to the initial condition of depth. We conducted psychological experiments to verify the model prediction. An ambiguous stimulus was presented after a prior stimulus removed ambiguity. The inter-stimulus interval (ISI) was inserted between the prior stimulus and post-stimulus. Results show that correlation of perception between the prior stimulus and post-stimulus depends on the ISI duration. Correlation is positive, negative, and nearly zero in the respective cases of short (0-200 ms), medium (200-400 ms), and long ISI (>400 ms). Furthermore, based on our model, we propose a computational model that can explain the dependence. Copyright © 2017 Elsevier Ltd. All rights reserved.

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

Science.gov (United States)

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

2015-10-30

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

Valuation of climate change mitigation co-benefits

DEFF Research Database (Denmark)

Bakhtiari, Fatemeh

a broad range of economic or, more likely, environmental and social issues. Examples of positive environmental impacts that may not be the primary outcome of a climate change mitigation policy include reduced local air pollution or restored ecosystem health. Examples of positive social impacts include......This document describes tools for valuating in monetary terms the co-benefits associated with climate change mitigation actions. The term co-benefits refers to outcomes of those actions other than their primary outcome (reducing greenhouse-gas emissions). Such non-primary outcomes can fall under...... improved human health or increased access to clean energy....

P--V--T and sound velocity data for fluid n-D2 in the range 75-300 K and 2-20 kbar

International Nuclear Information System (INIS)

Liebenberg, D.H.; Mills, R.L.; Bronson, J.C.

1977-11-01

Simultaneous static measurements of pressure, volume, temperature, and sound velocity are reported in deuterium fluid in the range 75 less than or equal to T less than or equal to 300K and 2 less than or equal to P less than or equal to 20 kbar [0.2 to 2.0 GPa]. The 1340 sets of data points along the 33 different isotherms are presented so that they may be available for use in equation-of-state development

State of the art of mitigation and relation mitigation/adaptation

Energy Technology Data Exchange (ETDEWEB)

Lenstra, W.J.; Van Doorn, J.; Verheggen, B.; Sahan, E.; Boersma, A.R. [ECN Biomass, Coal and Environment Research, Petten (Netherlands)

2009-04-15

This study has the main purpose to make useful information available for the programming of the Knowledge for Climate (KfC) program. The emphasis has been laid on a broad overview of mitigation options and relations, complemented with more detailed information on new or less known options and insights. The mitigation option biomass gets special attention in this study. The production of biomass has many (positive and negative) relations with other elements of the KfC program like space use and adaptation. Recently a global discussion on biomass usage for biofuels has started (food or fuel). Therefore a separate chapter will be dedicated to the sustainability aspects of biomass. An overview of technical mitigation measures with emphasis on the energy supply side is presented. This overview shows the large number of available and innovative options and the vast potential for reduction of the emissions of Greenhouse Gases (GHG) of these mitigation measures. The effectiveness of many mitigation options is strongly dependent on local conditions and implementation issues. A number of innovative mitigation measures such as aquatic biomass and biomass in combination with Carbon Capture and Storage (CCS) are described in more detail. Biomass for energy has many different forms and applications. It is one of the mitigation options with a high potential, but at the same time it can have negative environmental impacts and might compete with other forms of land use including food production. This makes bio-energy a promising but complex option, which makes careful evaluation necessary. Several examples of multifunctional land use show that by combining functions, synergy can be achieved. This could lead to a reduction of potentially negative impacts and thus easier implementation. Furthermore, novel technologies for reducing or offsetting climate change such as air capture and artificial cooling might have a high potential as mitigation option, but need to be examined before

Atmospheric kinematics of high velocity long period variables

International Nuclear Information System (INIS)

Willson, L.A.

1982-01-01

Radial velocities of atomic absorption lines of three long period variables, RT Cyg, Z Oph and S Car, have been analysed in order to understand velocity gradients and discontinuities in their atmospheres. Phase coverage is from five days before maximum to 73 days after maximum for RT Cyg, from 17 days before to 44 days after maximum for Z Oph, and at 9 days before maximum for S Car. On a few spectrograms double lines were seen. All spectrograms were analysed by a four-parameter regression programme to yield the dependence of the radial velocity on the excitation potential, first ionization potential, wavelength and line strength, as indicators of the depth of line formation. The data were analysed to yield the velocity discontinuity across shock waves and velocity gradients between shock waves. Near maximum light the radial velocities cannot be understood by the presence of one shock only but rather require two shocks. The lower shock becomes apparent at the longer wavelengths. Consistent parameters are obtained if these stars are fundamental mode pulsators with total masses in the range of 0.5 to 1.0 solar mass and effective radii in the range of 0.85 to 1.5 x 10 13 cm. (author)

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

Science.gov (United States)

Mahdi, Ghada S.

2012-01-01

Though age and gender do not affect students' knowledge of global issues and associated ambiguity, the academic major of undergraduates did. Students' combined perceptions on knowledge of these issues and their associated ambiguities varied among the four academic groups of majors. Unlike teacher education majors and in combined other majors…

Context sensitivity and ambiguity in component-based systems design

Energy Technology Data Exchange (ETDEWEB)

Bespalko, S.J.; Sindt, A.

1997-10-01

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

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

Science.gov (United States)

Zou, Linda X; Dickter, Cheryl L

2013-01-01

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

The association between tolerance for ambiguity and fear of negative evaluation: A study of engineering technology capstone courses

Science.gov (United States)

Dubikovsky, Sergey I.

For many students in engineering and engineering technology programs in the US, senior capstone design courses require students to form a team, define a problem, and find a feasible technical solution to address this problem. Students must integrate the knowledge and skills acquired during their studies at the college or university level. These truly integrative design activities do not have a single "correct" solution. Instead, there is an array of solutions, many of which could be used to achieve the final result. This ambiguity can cause students to experience anxiety during the projects. This study examined the main topics: • To what extent is a social anxiety (measured as fear of negative evaluation) related to tolerance for ambiguity in senior engineering capstone courses? • How does exposure to ambiguity prior to and during capstone courses affect tolerance for ambiguity? The study looked at the standard educational practices to see if they have unintended consequences, such a social anxiety in dealing with ambiguity. Those consequences are highly undesirable because they reduce students' learning. It was hypothesized that the lecture-based approaches that are more common in the first three years of study would not prepare students for self-directed capstone courses because the students would rarely have experienced problem-based learning before. The study used a quantitative approach and examined students' perceptions of their tolerance for ambiguity, and social anxiety before and after their senior capstone design experience. A survey instrument was adapted to measure exposure to ambiguity, which was studied as a potential moderator of the relationship between social anxiety and tolerance for ambiguity. The study indicated that social anxiety, as measured by fear of negative evaluation, does not play a major role in capstone courses. The second finding is that a single course, even if it was administered as a problem-based senior class, failed to

Mitigation - how to buy time

International Nuclear Information System (INIS)

Gunasekera, D.

2007-01-01

Full text: Full text: There is growing consensus in the global scientific community that human induced greenhouse gas emissions have increased the atmospheric concentration of these gases which has led, and will continue to lead to changes in regional and global climate. Climate change is projected to impact on Australian and global economic, biophysical, social and environmental systems. The impacts of climate change can be reduced by implementing a range of mitigation and adaptation strategies. The optimal policy response will depend on the relative costs and benefits of climate change impacts, and mitigation and adaptation responses. The focus in this presentation is to identify the key determinants that can reduce the cost of international mitigation responses. It is important to recognise that since cumulative emissions are the primary driver of atmospheric concentrations, mitigation policies should be assessed against their capacity to reduce cumulative emissions overtime, rather than at given time points only. If global greenhouse gas abatement costs are to be minimised, it is desirable that the coverage of countries, emission sources and technologies that are a part of any multilateral effort be as wide as possible. In this context the development and diffusion of clean technologies globally can play a key role in the future reduction of greenhouse gas emissions, according to scenarios analysed by ABARE. Furthermore, technology 'push' (for example, research and development policies) and 'pull' (for example, emission trading) policies will be required to achieve such an outcome

Integration of Regional Mitigation Assessment and Conservation Planning

Directory of Open Access Journals (Sweden)

James H. Thorne

2009-06-01

Full Text Available Government agencies that develop infrastructure such as roads, waterworks, and energy delivery often impact natural ecosystems, but they also have unique opportunities to contribute to the conservation of regional natural resources through compensatory mitigation. Infrastructure development requires a planning, funding, and implementation cycle that can frequently take a decade or longer, but biological mitigation is often planned and implemented late in this process, in a project-by-project piecemeal manner. By adopting early regional mitigation needs assessment and planning for habitat-level impacts from multiple infrastructure projects, agencies could secure time needed to proactively integrate these obligations into regional conservation objectives. Such practice can be financially and ecologically beneficial due to economies of scale, and because earlier mitigation implementation means potentially developable critical parcels may still be available for conservation. Here, we compare the integration of regional conservation designs, termed greenprints, with early multi-project mitigation assessment for two areas in California, USA. The expected spatial extent of habitat impacts and associated mitigation requirements from multiple projects were identified for each area. We used the reserve-selection algorithm MARXAN to identify a regional greenprint for each site and to seek mitigation solutions through parcel acquisition that would contribute to the greenprint, as well as meet agency obligations. The two areas differed in the amount of input data available, the types of conservation objectives identified, and local land-management capacity. They are representative of the range of conditions that conservation practitioners may encounter, so contrasting the two illustrates how regional advanced mitigation can be generalized for use in a wide variety of settings. Environmental organizations can benefit from this approach because it provides a

AMBIGUOUS JANUS OF MODERN DEMOCRACY

Directory of Open Access Journals (Sweden)

Volodymyr V. Khmil

2016-06-01

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

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

Science.gov (United States)

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

2014-01-01

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

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

Science.gov (United States)

Basöz, Tutku

2015-01-01

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

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

Science.gov (United States)

Li, Andrew; Bagger, Jessica

2008-01-01

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

The reciprocal dynamic model of career decision ambiguity tolerance with career indecision: A longitudinal three-wave investigation.

Science.gov (United States)

Xu, Hui; Tracey, Terence J G

2017-10-01

The current study investigated the dynamic interplay of career decision ambiguity tolerance and career indecision over 3 assessment times in a sample of college students (n = 583). While the previous research has repeatedly shown an association of career decision ambiguity tolerance with career indecision, the direction of this association has not been adequately assessed with longitudinal investigation. It was hypothesized in this study that there is a reciprocal pattern of career decision ambiguity tolerance leading to subsequent career indecision and career indecision leading to subsequent career decision ambiguity tolerance. Using a cross-lagged panel design, this study found support for the reciprocal pattern that aversion to ambiguity led to increased negative affect and choice anxiety in career decision making, while negative affect and choice anxiety led to increased aversion to ambiguity. Additionally, this study revealed that aversion led to decreased readiness for career decision making and readiness for career decision making led to increased interests in new information. The key findings were discussed with respect to the theoretical and clinical implications for career counseling along with limitations and suggestions for future research. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

Shuttlecock Velocity of a Badminton Drop Shot

Directory of Open Access Journals (Sweden)

Ampharin Ongvises

2013-01-01

Full Text Available In a badminton ‘drop shot’, the shuttlecock is struck by a non-rotating racquet at low speed. In this investigation, a shuttlecock was hit by a badminton racquet in a linear collision, simulating a drop shot. The collision was recorded with high-speed video and the velocities of the racquet and shuttlecock determined. The relationship between the impact velocity of the racquet and the velocity of the shuttlecock as it leaves the badminton racquet after collision was found to be proportional over the range tested.

Shuttlecock Velocity of a Badminton Drop Shot

Directory of Open Access Journals (Sweden)

Ampharin Ongvises

2013-12-01

Full Text Available In a badminton ‘drop shot’, the shuttlecock is struck by a non-rotating racquet at low speed. In this investigation, a shuttlecock was hit by a badminton racquet in a linear collision, simulating a drop shot. The collision was recorded with high-speed video and the velocities of the racquet and shuttlecock determined. The relationship between the impact velocity of the racquet and the velocity of the shuttlecock as it leaves the badminton racquet after collision was found to be proportional over the range tested.

Resolution of potential ambiguities through farside angular structure: Semiclassical analysis

International Nuclear Information System (INIS)

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

1988-01-01

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

The ambiguity of US foreign policy towards Africa

DEFF Research Database (Denmark)

Olsen, Gorm Rye

2017-01-01

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

GLONASS CDMA L3 ambiguity resolution and positioning

NARCIS (Netherlands)

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

2016-01-01

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

Do children exploit the Maxim of Antecedent in order to interpret ambiguous descriptions?

Science.gov (United States)