bluuebunny/crossref_metadata_2025 huggingface dataset:
Use of forecasted assessment of quality of life to validate time‐trade‐off utilities and a prostate cancer screening decision‐analytic model
Authors: Cantor Scott B. , Deshmukh Ashish A. , Krahn Murray D. , Volk Robert J.
Published: October 2013

Purpose

To determine whether the forecasted assessment of how someone would feel in a future health state can be predictive of utilities (e.g. as elicited by the time‐trade‐off method) and also predictive of optimal decisions as determined by a decision‐analytic model.

Methods

We elicited time‐trade‐off utilities for prostate cancer treatment outcomes from 168 men. We also elicited forecasted assessments, that is, an informal, non‐quantitative, descriptive evaluation, of impotence and incontinence from these men. We used multivariate regression analysis to explore the relationship between forecasted assessment and reluctance to trade length for improved quality of life, that is, the unwillingness to trade length of life for improved quality of life in the time‐trade‐off utility assessment and the relationship between the forecasted assessments and the optimal decision of whether to undergo screening for prostate cancer as determined from a previously published decision‐analytic model.

Results

Importance of sexual function was strongly related to impotence utilities (P < 0.05). Based on the multivariate analysis, significant predictors for the utility of severe incontinence were family income, family history of prostate cancer, work status and attitude towards needing to wear an incontinence pad. However, no variables were statistically significant predictors for the utility of complete impotence. The importance of sexual functioning was a significant predictor of the optimal decision.

Conclusion

Anticipated difficulty adjusting to adverse health effects were highly related to preferences and could be used as a proxy measure of utility. Similarly, the importance of sexual functioning, a future preference, was highly related to the optimal decision, which validates our previously published decision‐analytic model.
Study Protocol of the Restore4Stroke Self-Management Study: A Multicenter Randomized Controlled Trial in Stroke Patients and Their Partners
Authors: Tielemans Nienke S. , Visser-Meily Johanna M. A. , Schepers Vera P. M. , Post Marcel W. M. , Wade Derick T. , van Heugten Caroline M.
Published: October 2013

Rationale

Many stroke patients and their partners report long-term negative consequences of stroke on their health-related quality of life. Adequate self-management abilities may help manage the consequences of the stroke, but it is unknown what specific intervention might be effective to enhance self-management abilities of stroke patients and their partners.

Aim

The study aims to investigate the effectiveness of a 10-week group self-management intervention addressing proactive coping strategies compared with a group education intervention in stroke patients and their partners.

Design

The study is a multicenter randomized controlled trial. A total of 106 stroke patients with, if applicable, their partners are randomly assigned to the self-management intervention or the education intervention within each of the 10 participating hospitals and rehabilitation centers. The main inclusion criteria are a symptomatic stroke at least six-weeks ago, living at home, and reporting at least two participation restrictions on the Utrecht Scale for Evaluation of Rehabilitation-Participation's restriction scale. Measurements are performed at baseline, immediately after intervention, three-months, and nine-months postintervention.

Study outcomes

Primary outcome measures are stroke patients' and partners' proactive coping competencies (Proactive Competence Inventory) and societal participation (Utrecht Scale for Evaluation of Rehabilitation-Participation's restriction scale).

Discussion

If effective, the results of this study will enable stroke patients and their partners to deal better with the lasting consequences of stroke. In the context of the growing number of people returning home after stroke, a large number of people may profit from this intervention.
The Influence of Psychological Factors on Health-Related Quality of Life after Stroke: A Systematic Review
Authors: van Mierlo Maria L. , Schröder Carin , van Heugten Caroline M. , Post Marcel W. M. , de Kort Paul L. M. , Visser-Meily Johanna M. A.
Published: October 2013

Background and purpose

Many stroke patients experience problems with health-related quality of life, but much of the variance of health-related quality of life after stroke remains unexplained. Health-related quality of life may be influenced by psychological factors, as these factors reflect the way people approach situations and react to stressful situations. The aim of this study was to systematically examine the relationship between psychological factors and health-related quality of life after stroke.

Summary of review

A systematic literature search was conducted in online databases PubMed, Embase, PsycINFO, and CINAHL in November 2011. A total of nine studies were included. Personality (i.e. problems of temperament and personality functions and neuroticism) was moderately negatively associated with health-related quality of life ( r = 0·26–0·49). Coping (i.e. situational and personal adaptation), internal locus of control, self-worth (i.e. self-esteem and self-efficacy), and hope and optimism were moderately positively associated with health-related quality of life ( r = 0·026–0·81). No evidence was found for an association between extraversion and health-related quality of life.

Conclusions

There is still a paucity of studies on psychological determinants of poststroke health-related quality of life. The reviewed studies supported the importance of psychological factors, but further research is needed to supplement the available evidence and to examine how psychological factors can be modified to improve health-related quality of life, and at what moment after the stroke these interventions should be given.
Types of Stroke Recurrence in Patients with Ischemic Stroke: A Substudy from the PRoFESS Trial
Authors: Toni Danilo , Di Angelantonio Emanuele , Di Mascio Maria Teresa , Vinisko Richard , Bath Philip MW ,   for the PRoFESS Study Group
Published: October 2013

Background

Risk profiles for stroke recurrence are poorly characterized.

Aims

We determined the variation in the risk and type of recurrent stroke among index ischemic stroke subtypes, and whether index stroke subtype and conventional stroke risk factors were predictors of stroke recurrence.

Methods

Patients enrolled in the Prevention Regimen for Effectively Avoiding Second Strokes trial were included in this study.

Results

In 1794 patients' recurrent stroke subtypes were the same as the index stroke in: 48·3% of patients with large artery atherothrombosis stroke; 50% of patients with cardioembolic stroke; 48·7% of patients with small artery occlusion stroke; 8·1% of patients with stroke of other etiology, and 45·3% of patients with undetermined etiology stroke. Patients with cardioembolic stroke, who were unwilling or unable to take oral anticoagulants, had the greatest risk of stroke recurrence. Predictors of stroke recurrence in multivariable analysis were: older age and previous stroke among large artery atherothrombosis strokes; older age, male sex, previous stroke, previous transient ischemic attack, hypertension, diabetes, and tobacco use among small artery occlusion strokes; older age among cardioembolic strokes; atrial fibrillation and anti-diabetic medications among other etiology strokes; older age, previous stroke and atrial fibrillation among undetermined etiology strokes. Predictors of brain hemorrhage as recurrent stroke were index small artery occlusion stroke, older age, previous stroke, and antiplatelet treatment with aspirin plus extended-release dipyridamole.

Conclusions

Risk predictors for stroke recurrence and for brain hemorrhage differ by index ischemic stroke subtype, information that is important when initiating secondary prevention therapy.
Incidence and Outcome of Cerebrovascular Events Related to Cervical Artery Dissection: The Dijon Stroke Registry
Authors: Béjot Yannick , Daubail Benoit , Debette Stéphanie , Durier Jérôme , Giroud Maurice
Published: October 2013

Background

Reliable epidemiological data on the true incidence of cerebrovascular events related to spontaneous cervical artery dissection, including stroke and transient ischemic attack, are scarce.

Aims

To evaluate the incidence, characteristics, and outcome of cerebrovascular events due to cervical artery dissection. Methods All cerebrovascular events (stroke and transient ischemic attack) occurring in Dijon, France, from 2006 to 2011, were retrieved from a population-based registry. Patients with a cervical artery dissection were identified. Incidence rates, baseline characteristics, and outcome at three-months were described.

Results

Among the 1368 patients with cerebrovascular events, 27 had cervical artery dissection (2·0%, 52% men, mean age 49·1 ± 17·1), including 10 patients with internal carotid artery dissection, 16 patients with vertebral artery dissection, and one patients with both internal carotid artery dissection and vertebral artery dissection. The crude incidence rate of cerebrovascular events due to cervical artery dissection was 2·97/100 000/ year. Corresponding rates were 1·21/100 000/year for internal carotid artery dissection, and 1·87/100 000/year for vertebral artery dissection. Seventy per cent of patients had a stroke and among these, higher severity was observed in those with internal carotid artery dissection. A good outcome (m-Rankin score 0–2) was observed in 89% of patients at three-months, whatever the location of the cervical artery dissection. One patient with vertebral artery dissection died at day 38.

Conclusion

The incidence of cerebrovascular events related to vertebral artery dissection is greater than previously reported, which may indicate a better identification of patients due to improvements in diagnostic procedures.
Scaling of species distribution models across spatial resolutions and extents along a biogeographic gradient. The case of the Iberian mole Talpa occidentalis
Authors: Suárez‐Seoane Susana , Virgós Emilio , Terroba Olga , Pardavila Xosé , Barea‐Azcón Jose M.
Published: October 2013

Scaling is a key process in modelling approaches since it allows for translating information from one scale to another. However, the success of this procedure may depend on ‘source’ and ‘target’ scales, but also on the biogeographic/ecological context of the study area. We aimed to quantify the performance and success of scaling species distribution model (SDM) predictions across spatial resolution and extent along a biogeographic gradient using the Iberian mole as study case. We ran separate MaxEnt models at two extents (national and regional) using independent datasets (species locations and environmental predictors) collected at 10 km and 50 m resolutions respectively. Model performance and success of scaling SDMs were quantified on the basis of accuracy measures and spatial predictions. Complementarily, we calculated marginality and tolerance as indicators of habitat availability and niche truncation along the biogeographic gradient. Model performance increased with resolution and extent, as well as from north to south (mainly for high resolution models). When regional models were validated at different scales, their performance reduced severely, particularly in the case of coarse resolution models (some of them performed worse than random). However, when the 10 km‐national model was downscaled within regions, it performed better (AUCtest: 0.82, 0.85 and 0.55 respectively for Galicia, Madrid and Granada) than models specifically calibrated within each region at 10 km (0.47, 0.65, 0.44). Indeed, it also had a better accuracy when projected at 50 m (0.77, 0.91, 0.79) than models fitted at that resolution (0.62, 0.83, 0.96) in two of the three cases. The success of scaling model predictions decreased along the biogeographic gradient, being these differences associated to niche truncation. Models representing non‐truncated niches were more successfully scaled across resolutions and extents (particularly in areas not offering all possible habitats for species), which has important implications for SDM applications.
Race, Prediction, and Pretrial Detention
Authors: McIntyre Frank , Baradaran Shima
Published: October 2013

This article uses the nationally representative State Court Processing Statistics on felony defendants to analyze how judges decide if defendants should be held pretrial. We find a large (11 percentage points) racial gap in hold rates within a county. Judicial decisions are significantly influenced by the probability that the defendant will be rearrested pretrial for a violent felony. Controlling for this probability causes the racial gap in hold rates to disappear. Bail amounts follow the same pattern. The most plausible sources of bias—mismeasurement of the control probabilities or selection bias—likely either do not matter or cause an upward bias.
Advancing the nutrition and early childhood development agenda: indicators and guidance
Authors: Pelletier David , Neuman Michelle J.
Published: October 2013

The importance of early childhood development (ECD) is scientifically established and is increasingly recognized by governments and international organizations. However, progress in protecting and improving ECD is constrained by multisectoral influences on ECD, the multiple sectors and venues for delivering services, the lack of a common fiscal and policy space, and weak or fragmented data and monitoring systems. This paper describes two tools and strategies to strengthen multisectoral, system‐wide policy environments for ECD. One is the Systems Approach for Better Education Results (SABER)‐ECD framework for tracking progress toward an integrated ECD system. Developed by the World Bank, SABER‐ECD assists governments and their partners to take stock of their existing ECD policies and programs, analyze strengths and areas for improvement using common metrics, and learn from international examples. The other tool is an Agenda‐Setting and Commitments framework, based on research in global health and nutrition that can guide national‐level actors in their advocacy and strategic efforts to strengthen the integrated ECD system. These represent practical and research‐based tools to translate scientific evidence concerning ECD into effective and large‐scale actions.
Scientific foundation, patents, and new product introductions of biotechnology and pharmaceutical firms
Authors: Watts Allison D. , Hamilton Robert D.
Published: October 2013

Absorptive capacity (ACAP) has long been used in the research of technology firms as an indication of knowledge acquisition. This paper links knowledge input using new product introductions (NPI), to commercial output, addressing one of the key criticisms of research and development expenditures as a measure of an organization's effort. We propose that firms with a strong basic science foundation such as biology and chemistry seek to advance their scientific knowledge in addition to developing and selling innovative products. In contrast, corporations with a more applied focus forego fundamental scientific advancement and concentrate their actions on the development of innovative products. Results from a sample of 487 firms over a 10‐year period indicated that firms with an applied science foundation had greater numbers of NPIs, both breakthrough and innovative, suggesting that a solutions‐based approach had greater value in terms of innovative output. The pursuit of science may build knowledge, but a clear link between increased ACAP and innovative output was not found. Our results also suggest that basic science firms have a positive relationship with both breakthrough and incremental NPIs using merger and acquisition activities. Applied science firms found university alliances useful in generating NPIs.
Knowledge spillovers: cooperation between universities and KIBS
Authors: Fernandes Cristina I. , Ferreira João J. M.
Published: October 2013

Knowledge is increasingly perceived as a fulcral factor to company competitiveness. As the transfer of knowledge is one of the key functions of knowledge intensive business services (KIBS), this research seeks to analyse how the transfer of knowledge takes place between the higher education sector and KIBS type firms. The empirical results show that cooperation between KIBS and universities occurs irrespective of the typology (whether professional or technological in focus). We also empirically establish how geographic proximity is the factor bearing greatest influence over cooperation while such cooperation proves to have a positive impact on the company capacity to innovate. We furthermore find that this innovation capacity also drives a positive company financial performance.
Foundational Issues in Risk Assessment and Risk Management
Authors: Aven Terje , Zio Enrico
Published: October 2013

This is a perspective article on foundational issues in risk assessment and management. The aim is to discuss the needs, obstacles, and challenges for the establishment of a renewed, strong scientific foundation for risk assessment and risk management suited for the current and future technological challenges. The focus is on (i) reviewing and discussing the present situation and (ii) identifying how to best proceed in the future, to develop the risk discipline in the directions needed. The article provides some reflections on the interpretation and understanding of the concept of “foundations of risk assessment and risk management” and the challenges therein. One main recommendation is that different arenas and moments for discussion are needed to specifically address foundational issues in a way that embraces the many disciplinary communities involved (from social scientists to engineers, from behavioral scientists to statisticians, from health physicists to lawyers, etc.). One such opportunity is sought in the constitution of a novel specialty group of the Society of Risk Analysis.
Toward Disaster‐Resilient Cities: Characterizing Resilience of Infrastructure Systems with Expert Judgments
Authors: Chang Stephanie E. , McDaniels Timothy , Fox Jana , Dhariwal Rajan , Longstaff Holly
Published: October 2013

Resilient infrastructure systems are essential for cities to withstand and rapidly recover from natural and human‐induced disasters, yet electric power, transportation, and other infrastructures are highly vulnerable and interdependent. New approaches for characterizing the resilience of sets of infrastructure systems are urgently needed, at community and regional scales. This article develops a practical approach for analysts to characterize a community's infrastructure vulnerability and resilience in disasters. It addresses key challenges of incomplete incentives, partial information, and few opportunities for learning. The approach is demonstrated for Metro Vancouver, Canada, in the context of earthquake and flood risk. The methodological approach is practical and focuses on potential disruptions to infrastructure services. In spirit, it resembles probability elicitation with multiple experts; however, it elicits disruption and recovery over time, rather than uncertainties regarding system function at a given point in time. It develops information on regional infrastructure risk and engages infrastructure organizations in the process. Information sharing, iteration, and learning among the participants provide the basis for more informed estimates of infrastructure system robustness and recovery that incorporate the potential for interdependent failures after an extreme event. Results demonstrate the vital importance of cross‐sectoral communication to develop shared understanding of regional infrastructure disruption in disasters. For Vancouver, specific results indicate that in a hypothetical M7.3 earthquake, virtually all infrastructures would suffer severe disruption of service in the immediate aftermath, with many experiencing moderate disruption two weeks afterward. Electric power, land transportation, and telecommunications are identified as core infrastructure sectors.
Disowned by the Ownership Society: How Native Americans Lost Their Land
Authors: Geisler Charles
Published: October 2013

Over the past five centuries, Europeans have enclosed the global commons and, in the process, incorporated whole continents of aboriginal land. Some scholars argue that Indians in North America were spared the ravages of compulsory enclosure, having sold their land to non‐Indians through willing‐seller transactions and benefited from federal government trust and treaty policies. Moreover, where enclosure existed, it is widely believed to have ended as Indians converted to agriculture, thereby internalizing hard work, sedentary life styles, and allotted ownership. This study disputes such historical accounts and suggests a wave of new enclosures in accordance with recent U.S. Department of Agricultural minority lending policies. By discriminating against Native American farmers and ranchers, the federal government has enabled the erasure of title, livelihood opportunities, and cultural identity among Indian farming and ranching communities. Evidence from the Fort Berthold Reservation of North Dakota reveals the complex complicity of the federal government in Indian land erasure and points to a changing reservation geography that, even now, makes castaways of agrarian Indians.
Patient dose simulations for scanning‐beam digital x‐ray tomosynthesis of the lungs
Authors: Nelson Geoff , Yoon Sungwon , Krishna Ganesh , Wilfley Brian , Fahrig Rebecca
Published: October 2013

Purpose:

An improved method of image guidance for lung tumor biopsies could help reduce the high rate of false negatives. The aim of this work is to optimize the geometry of the scanning‐beam digital tomography system (SBDX) for providing real‐time 3D tomographic reconstructions for target verification. The unique geometry of the system requires trade‐offs between patient dose, imaging field of view (FOV), and tomographic angle.

Methods:

Tomosynthetic angle as a function of tumor‐to‐detector distance was calculated. Monte Carlo Software (PCXMC) was used to calculate organ doses and effective dose for source‐to‐detector distances (SDDs) from 90 to 150 cm, patient locations with the tumor at 20 cm from the source to 20 cm from the detector, and FOVs centered on left lung and right lung as well as medial and distal peripheries of the lungs. These calculations were done for two systems, a SBDX system and a GE OEC‐9800 C‐arm fluoroscopic unit. To evaluate the dose effect of the system geometry, results from PCXMC were calculated using a scan of 300 mAs for both SBDX and fluoroscopy. The Rose Criterion was used to find the fluence required for a tumor SNR of 5, factoring in scatter, air‐gap, system geometry, and patient position for all models generated with PCXMC. Using the calculated fluence for constant tumor SNR, the results from PCXMC were used to compare the patient dose for a given SNR between SBDX and fluoroscopy.

Results:

Tomographic angle changes with SDD only in the region near the detector. Due to their geometry, the source array and detector have a peak tomographic angle for any given SDD at a source to tumor distance that is 69.7% of the SDD assuming constant source and detector size. Changing the patient location in order to increase tomographic angle has a significant effect on organ dose distribution due to geometrical considerations. With SBDX and fluoroscopy geometries, the dose to organs typically changes in an opposing manner with changing patient location. When tumor SNR is held constant (i.e., x‐ray fluence is scaled appropriately), SBDX gives 2–10 times less dose than fluoroscopy for the same conditions within the typical range of patient locations. The relative position of the patient (as a percent of SDD) has a much more significant impact on dose than either SDD or patient position. The patient position providing the minimum dose for a given tumor SNR and SDD is approximately the same as the position of maximum tomographic angle.

Conclusions:

SBDX offers a significant dose advantage over currently used C‐arm fluoroscopy. The patient location with lowest dose coincides with the location of maximum tomographic angle. In order to provide adequate space for the patient and for the pulmonologists’ equipment, a SDD of 100 cm is recommended.
A random walk to stochastic diffusion through spreadsheet analysis
Authors: Brazzle Bob
Published: October 2013

This paper describes a random walk simulation using a number cube and a lattice of concentric rings of tiled hexagons. At the basic level, it gives beginning students a concrete connection to the concept of stochastic diffusion and related physical quantities. A simple algorithm is presented that can be used to set up spreadsheet files to calculate these simulated quantities and even to “discover” the diffusion equation. Lattices with different geometries in two and three dimensions are also presented. This type of simulation provides fertile ground for independent investigations by all levels of undergraduate students.
On the connection between image formation formulas in geometrical optics and beam transformation formulas in wave optics
Authors: Bisson Jean-François
Published: October 2013

The close connection between image formation in geometrical optics and beam transformation by a paraxial optical system is examined analytically using mathematical tools accessible to undergraduate students, such as the Fresnel diffraction integral and Fourier transforms, instead of the more complicated Wigner distribution or coherence functions frequently employed in the literature. It is shown that geometrical optics correctly predicts the plane where a beam is refocused and its magnification only for afocal optical systems or in the limit of point sources. We illustrate this theory by simulating the transformation of a flat-top beam by a pair of lenses.
Exact solution of the compressed hydrogen atom
Authors: Ferreyra J. M. , Proetto C. R.
Published: October 2013

The exact solution to the problem of a hydrogen atom confined in a spherical well (CHA) is discussed; the standard results for the unconfined hydrogen atom (UHA) are recovered as the sphere size becomes large compared to the Bohr radius. The solutions are characterized by a set of three quantum numbers N (= 1, 2, 3,…), L (= 0, 1, 2,…), and M (= − L, − L + 1,…, L − 1, L), and the energy eigenvalues, in contrast to the situation in the UHA, depend on both N and L. All members of a given family n = N + L, however, evolve asymptotically toward the same energy level in the large-sphere limit, recovering the typical n2 degeneracy of the UHA. Besides numerically exact solutions for arbitrary sphere sizes, rigorous analytical approximations are provided for the physically relevant strong- and weak-confinement regimes. A conjecture concerning the ordering of the energy levels is rigorously confirmed. The validity of the virial theorem, Kato's cusp condition, and the role played by the density as an alternative basic variable for the case of the CHA are discussed.
Neural network analysis of soundscape in urban open spaces
Authors: Yu Lei , Kang Jian
Published: October 2013

The physical and social environments of open spaces in a city influence people’s behavior as well as their perception of the city. Soundscape is an important component of an open urban space, and key aspects for producing a good soundscape include its description, evaluation, and design. In this research, an artificial intelligent system is being developed for the analysis of soundscape evaluation in urban open spaces. The system considers acoustic factors including the level, type and spectrum of sound sources and the reflection effects of an urban space; users social and demographic factors; and other physical and environmental factors including urban morphology, microclimate conditions, and thermal and visual comfort. Since 2001 a large scale social survey has been carried out in England, Switzerland, Italy, Greece, Germany and China. Correspondingly, a database suitable for artificial neural networks (ANN) modeling has been established. Simulating biological brains, ANN are simplified models of the central nervous system, which have the ability to respond to input stimuli and to learn to adapt to the environment. The software Qnet is being used, and initial results suggest that there is a good convergence of using ANN to predict peoples perception of soundscape in urban open spaces.
Techniques of analysis and their applicability in the context of community noise
Authors: Fiebig Andre , Schulte-Fortkamp Brigitte
Published: October 2013

There is common consent to the necessity using and combining subjective and objective data for a sufficient understanding of human perception and evaluation of noise. Moreover, a wide discussion about methodology and techniques of analysis with respect to new methods in the context of soundscape research, community noise, and annoyance evaluation is urgently needed. The presentation at hand shows a methodological discussion of qualitative data and its systematic analysis based on explorative approaches applied in two different surveys. For example, by means of the analysis a transfer from verbal evaluations based on habitual language to acoustical descriptors is possible. Furthermore, the principals and steps of the analysis of qualitative data in the context of community noise are presented. Insofar, with regard to an effective and unitized handling, options and possibilities of methods in connection with specific techniques of analysis will be discussed.
An exact analytical expression of the shear coefficient in the Mindlin plate equation
Authors: Hull Andrew
Published: October 2013

This paper derives an exact analytical expression of the shear coefficient in the Mindlin plate equation for a plate of infinite extent. The equation of motion derived from the Mindlin plate equation is set equal to the equation of motion derived from the thick plate equation, and the result is a closed-form expression of the shear coefficient at all wave numbers and frequencies. A numerical example is included to illustrate the variation of the shear coefficient. It is shown that the shear coefficient is extremely dependent on wave number and only slightly dependent on frequency. Shear coefficients derived in other work are compared favorably to the values calculated by this new method at the plate flexural wave response. [Work funded by the Office of Naval Research.]
Vowel production and perception in French blind and sighted adults
Authors: Dupont Sophie , Menard Lucie
Published: October 2013

It is well known that visual cues play an important role in speech perception and production. Early in life, blind speakers, who do not have access to visual information related to lip and jaw movements, show a delay in the acquisition of phonological contrasts based on these visible articulatory features [A. E. Mills, Hearing by eye: The psychology of lip-reading, pp. 145–161 (1987)]. It has also been claimed that blind speakers have better auditory discrimination abilities than sighted speakers. The goal of this study is to describe the production-perception relationships involved in French vowels for blind and sighted speakers. Six blind adults and six sighted adults served as subjects. The auditory abilities of each subject were evaluated by auditory discrimination tests (AXB). At the production level, ten repetitions of the ten French oral vowels were recorded. Formant values and fundamental frequency values were extracted from the acoustic signal. Measures of contrasts (Euclidean distances) and dispersion (standard deviations) were computed and compared for each feature (height, place, roundedness) and group (blind, sighted). Regression analyses between discrimination scores and produced contrasts were carried out. Despite between-speaker variability, results show an effect of speakers group (blind versus sighted) on the produced contrast distances.
Echo integration of nonuniform fish densities
Authors: Kieser Robert , Hedgepeth John
Published: October 2013

Echo integration is a well recognized method for measuring backscatter intensity and for estimating fish density. EI is appropriate for high and low fish densities as long as the target distribution is uniform across the beam. This is generally the case in mobile applications that use a downward looking transducer. However uniform fish distribution across the beam cannot be assumed in riverine applications that use a stationary side looking system. Observed distributions are often very nonuniform especially when migrating fish are surface or bottom oriented. EI may still be possible if the relative vertical fish distribution is known and reasonably constant over time. A priori estimates of the vertical fish density distribution could be from split-beam observations when densities are lower or from video observations. A model for the EI of nonuniform fish densities is developed, typical results are simulated to test the model and its application is discussed.
The influence of different native language systems on vowel discrimination and identification
Authors: Kewley-Port Diane , Bohn Ocke-Schwen , Nishi Kanae
Published: October 2013

The ability to identify the vowel sounds of a language reliably is dependent on the ability to discriminate between vowels at a more sensory level. This study examined how the complexity of the vowel systems of three native languages (L1) influenced listeners perception of American English (AE) vowels. AE has a fairly complex vowel system with 11 monophthongs. In contrast, Japanese has only 5 spectrally different vowels, while Swedish has 9 and Danish has 12. Six listeners, with exposure of less than 4 months in English speaking environments, participated from each L1. Their performance in two tasks was compared to 6 AE listeners. As expected, there were large differences in a linguistic identification task using 4 confusable AE low vowels. Japanese listeners performed quite poorly compared to listeners with more complex L1 vowel systems. Thresholds for formant discrimination for the 3 groups were very similar to those of native AE listeners. Thus it appears that sensory abilities for discriminating vowels are only slightly affected by native vowel systems, and that vowel confusions occur at a more central, linguistic level. [Work supported by funding from NIHDCD-02229 and the American-Scandinavian Foundation.]
Acoustic surveillance for hazardous eruptions (ASHE)
Authors: McCormack David , Bass Henry , Garces Milton , Yepes Hugo
Published: October 2013

The potential of using infrasound to rapidly identify explosive volcanic eruptions has been discussed in the environmental acoustics and aviation safety communities for some time. The ability of sounds in the 0.01–10 Hz range to propagate for long distances with little attenuation suggests broad-area regional monitoring with a modest number of observing sites is possible. The ASHE experiment tests both the practical utility of infrasound as a regional-scale volcanic eruption detection tool, and the feasibility of using such an infrasound system to provide timely operational alerts to aviation through Volcanic Ash Advisory Centres (VAACs). Several infrasound arrays are deployed in a volcanic region, sending data in real time to a central detector, and onward to participating VAACs for comparison with existing warning systems. The ASHE experiment will determine if infrasound can complement both seismic and satellite observations to improve monitoring of volcanic hazard. Continuous acoustic surveillance can reduce the ambiguity between eruptive and purely seismic activity in an active volcano and provide additional estimates for the onset time of an eruption. The onset time estimates can be used as triggers for ash transport models.
Auralizations and other computer model studies to predict qualitative and quantitative measures of speech intelligibility in classrooms
Authors: Siebein Gary , Kim Hyeong-seok , Paek Hyun
Published: October 2013

Auralizations and other computer model studies were used to predict qualitative and quantitative measures of speech intelligibility in classrooms under realistic conditions of background noise and reverberation. Speech intelligibility tests were given to college students in two classrooms and one racquetball court at 5 signal-to-noise ratios. Auralizations of the speech intelligibility tests were made from computer. Speech intelligibility tests were then administered in a sound booth using the auralized material. Fifteen different acoustical measurements related to speech intelligibility were also made at multiple locations in the actual classrooms and in the computer models of the classrooms. The scores on the speech intelligibility tests given in the actual rooms in the five noise conditions were closely duplicated in the equivalent tests conducted in a sound booth using the simulated speech signals obtained in the computer models. Both quantitative and qualitative measures of speech intelligibility in the actual rooms were accurately predicted in the computer models. Correlations (R2) between acoustical measures made in the full size classrooms and the computer models of the classrooms of 0.92 to 0.99 were found.
Acoustic cues to Nehiyawewin constituency
Authors: Cook Clare , Muehlbauer Jeff
Published: October 2013

This study examines how speakers use acoustic cues, e.g., pitch and pausing, to establish syntactic and semantic constituents in Nehiyawewin, an Algonquian language. Two Nehiyawewin speakers autobiographies, which have been recorded, transcribed, and translated by H. C. Wolfart in collaboration with a native speaker of Nehiyawewin, provide natural-speech data for the study. Since it is difficult for a non-native-speaker to reliably distinguish Nehiyawewin constituents, an intermediary is needed. The transcription provides this intermediary through punctuation marks (commas, semi-colons, em-dashes, periods), which have been shown to consistently mark constituency structure [Nunberg, CSLI 1990]. The acoustic cues are thus mapped onto the punctuated constituents, and then similar constituents are compared to see what acoustic cues they share. Preliminarily, the clearest acoustic signal to a constituent boundary is a pitch drop preceding the boundary and/or a pitch reset on the syllable following the boundary. Further, constituent boundaries marked by a period consistently end on a low pitch, are followed by a pitch reset of 30–90 Hz and have an average pause of 1.9 seconds. I also discuss cross-speaker cues, and prosodic cues that do not correlate to punctuation, with implications for the transcriptional view of orthography [Marckwardt, Oxford 1942].
Discourse-level contours in Nehiyawewin
Authors: Muehlbauer Jeff , Cook Clare
Published: October 2013

This study describes declination and discourse-sized intonation contours in Nehiyawewin, an Algonquian language whose pitch and intonation systems have not been previously studied. The study draws on 270 min of recordings of two female Nehiyaw elders telling their life stories to another Nehiyawewin native speaker. Data is analyzed by using Praat’s default algorithm to generate f0 curves for each breath group. Preliminary results indicate: (1) When breath-group internal pitch peaks are considered, an obvious downward trend of f0 occurred in fewer than half the breath groups analyzed (about 40% or 37/90). This raises questions about the role of classical declination in natural discourse [Umeda, Journal of Phonetics 10 (1982)]. (2) When we abstract away from declination within a breath group by computing mean f0 and mean pitch peak for each breath group and tracking trends for these means, larger patterns seem to emerge; breath groups can be grouped into larger units based on raising and lowering trends. These units have a mean peak range of 150 Hz with a 30 Hz change from one breath group to the next and correspond to a domain of around five clauses (about 3–4 breath groups, about 45 syllables).
Maximum entropy method for constructing environmental parameter probability density functions
Authors: Sibul Leon H. , Culver R. Lee , Bradley David L. , Camin H. John
Published: October 2013

At-sea experience has shown that target detection ranges are often less than predicted using current sonar system performance prediction methods. One possible reason for this disparity is that classical, sonar equation-based performance prediction models do not take into account the random and uncertain nature of signal propagation and scattering in a real ocean environment. Our goal is to develop a probabilistic sonar performance prediction methodology that can make use of limited knowledge of random or uncertain environment, target and sonar system parameters, but does not make unwarranted assumptions or rely upon unknown information. Beginning with models that describe how the ocean environment effects the received signal, the Maximum Entropy method (MEM) can be used to construct probability density functions (PDFs) for the parameters of those models. The benefit of the MEM is that it allows one to incorporate available knowledge about the parameters, but is maximally non-committal about what is not known about the parameters. The methodology is presented and illustrated using a model for particular environmental effects on the structure of low-frequency signals propagating over long distances in the ocean. [Work supported by ONR Code 321US.]
Laser Doppler signal for high amplitude sound wave
Authors: Valiere Jean-Christophe , Moreau Solenn , Bailliet Helene , Herzog Philippe , Simon Laurent
Published: October 2013

Laser Doppler velocimetry (LDV) is now recognized as a very useful technique for estimating acoustic velocity with a good time resolution in many applications. Previous research showed that the most important parameter in LDV for acoustics is the particle displacement and particularly its magnitude compared with the size of the probe volume formed by the crossing of the laser beams. Specific techniques were developed to estimate the acoustic wave when the displacement is of the same order of magnitude as the probe diameter and when it is much smaller. In this study, we investigate situations where the displacement is much higher than the probe volume. The measuring process has been simulated numerically and it appears that the process leads to an under-estimation of the velocity around zero. This under-estimation is due to the processing of the laser Doppler signal in the case of high displacements. The associated signal is a non poissonnian randomly sampled signal to which classical processing methods are not adapted. It is compared to experimental signals obtained in the context of a study of non linear effects in an acoustic wave guide. To this end, different processing of both simulated and experimental signals are presented and compared.
Cross-frequency Doppler sensitive signal processing
Authors: Wagstaff Ronald A.
Published: October 2013

When there is relative motion between an acoustic source and a receiver, a signal can be Doppler shifted in frequency and enter or leave the processing bins of the conventional signal processor. The amount of the shift is determined by the frequency and the rate of change in the distance between the source and the receiver. This frequency Doppler shifting can cause severe reductions in the processors performance. Special cross-frequency signal processing algorithms have recently been developed to mitigate the effects of Doppler. They do this by using calculation paths that cut across frequency bins in order to follow signals during frequency shifting. Cross-frequency spectral grams of a fast-flying sound source were compared to conventional grams, to evaluate the performance of this new signal processing method. The Doppler shifts in the data ranged up to 70 contiguous frequency bins. The resulting cross-frequency grams showed that three paths provided small to no improvement. Four paths showed improvements for either up-frequency or down-frequency shifting, but not for both. Two paths showed substantial improvement for both up-frequency and down-frequency shifting. The cross-frequency paths will be defined, and comparisons between conventional and cross-frequency grams will be presented. [Work supported by Miltec Corporation.]
Models for attenuation in marine sediments that incorporate structural relaxation processes
Authors: Pierce Allan D. , Carey William M. , Lynch James F.
Published: October 2013

Biot’s model leads to an attenuation coefficient at low frequencies that is proportional to ω2, and such is consistent with physical models of viscous attenuation of fluid flows through narrow constrictions driven by pressure differences between larger fluid pockets within the granular configuration. Much data suggests, however, that the attenuation coefficient is linear in ω for some sediments and over a wide range of frequencies. A common model that predicts such a dependence stems from theoretical work by Stoll and Bryan [J. Acoust. Soc. Am. 47, 1440 (1970)], in which the elastic constants of the solid frame are taken to be complex numbers, with small constant imaginary parts. Such invariably leads to a linear ω dependence at sufficiently low frequencies and this conflicts with common intuitive notions. The present paper incorporates structural relaxation, with a generalization of the formulations of Hall [Phys. Rev. 73, 775 (1948)] and Nachman, Smith, and Waag [J. Acoust. Soc. Am. 88, 1584 (1990)]. The mathematical form and plausibility of such is established, and it is shown that the dependence is as ω2 at low frequencies, and that a likely realization is one where the dependence is linear in ω at intermediate frequency ranges.
Measuring dispersion and attenuation in sediment at low frequency
Authors: Stotts Steven A. , Koch Robert A. , Knobles David P.
Published: October 2013

Much work has been done at frequencies above 1 kHz to measure sediment dispersion and attenuation and these results have been analyzed within the context of various models such as Biot-Stoll, Buckingham, and BICSQS. Some effort has been made to establish the frequency dependence of sediment attenuation below 1 kHz, but few results are available concerning dispersion in that frequency band. The present work examines a technique for measuring low frequency sediment dispersion and attenuation with a real dataset. Recently, data were collected off the coast of Florida using implosive broadband sources to perform geo-acoustic inversions. Previous inversion studies with this data ignored any dispersion effects. [Stotts et al, J. Acoust. Soc. Am. 115, 1078–1102 (2004).] The environment was shown to consist of thin, hard, porous material less than 1 m thick overlying sand sediment. A ray trace plus plane-wave reflection coefficient model was used for the analysis. Here, dispersion is represented phenomenologically over a finite frequency band in the model by allowing both the sound speed and attenuation to be frequency dependent in both layers of a two-layer sediment plus substrate model.