bluuebunny/crossref_metadata_2025 huggingface dataset:
Longevity Adjustment of Retirement Age and Intragenerational Inequality
Authors: Hougaard Jensen Svend E. , Sigurdur Sveinsson Thorsteinn , Zoega Gylfi
Published: December 2020

We find that segments of society that have shorter life expectancy can expect a lower income from their pensions and lifetime utility due to the longevity of other groups participating in the same pension scheme. Linking the pension age to average life expectancy magnifies the negative effect on the lifetime utility of those who suffer low longevity. Furthermore, when the income of those with greater longevity increases, those with shorter life expectancy become even worse off. Conversely, when the income of those with shorter life expectancy increases, they end up paying more into the pension scheme, which benefits those who live longer. The relative sizes of the low‐ and high‐longevity groups in the population determine the magnitude of these effects. We calibrate the model based on data on differences in life expectancy of different socioeconomic groups and find that low‐income workers suffer from a 10–13% drop in pension benefits from being forced to pay into the same scheme as high‐income workers.
Heterozygosity of murine Crkl does not recapitulate behavioral dimensions of human 22q11.2 hemizygosity
Authors: Yamauchi Takahira , Kang Gina , Hiroi Noboru
Published: December 2020

Deletions in 22q11.2 human chromosome are known to be associated with psychiatric disorders, such as intellectual disability, schizophrenia, autism spectrum disorder, and anxiety disorders. This copy number variation includes a 3.0 Mb deletion and a nested proximal 1.5 Mb hemizygous deletion in the same region. Evidence indicates that the distal 22q11.2 region outside the nested 1.5 Mb deletion also might be contributory in humans. However, the precise genetic architecture within the distal region responsible for psychiatric disorders remains unclear, and this issue cannot be experimentally evaluated beyond the correlation in humans. As CRKL (CRK‐like Proto‐Oncogene, Adaptor Protein) is one of the genes encoded in the distal 22q11.2 segment and its homozygous deletion causes physical phenotypes of 22q11.2 hemizygous deletion, we tested the hypothesis that its murine homolog Crkl contributes to behavioral phenotypes relevant to psychiatric disorders in mice. Congenic Crkl heterozygosity reduced thigmotaxis, an anxiety‐related behavior, in an inescapable open field, but had no apparent effect on social interaction, spontaneous alternation in a T‐maze, anxiety‐like behavior in an elevated plus maze, or motor activity in an open field. Our data indicate that the heterozygosity of murine Crkl does not recapitulate social deficits, working memory deficits, repetitive behavior traits or hyperactivity of human 22q11.2 hemizygous deletion. Moreover, while 22q11.2 hemizygous deletion is associated with high levels of phobia and anxiety in humans, our data suggest that Crkl heterozygosity rather acts as a protective factor for phobia‐like behavior in an open field.
Perceptions of knowledge, attitude and skills about non‐suicidal self‐injury: A survey of emergency and mental health nurses
Authors: Ngune Irene , Hasking Penelope , McGough Shirley , Wynaden Dianne , Janerka Carrie , Rees Clare
Published: December 2020

Non‐suicidal self‐injury (NSSI) is a major public health concern and is also associated with increased risk of suicide. The type of care people with NSSI receive at the hospital impacts their health outcomes. This study explored emergency department (ED) and mental health nurses’ (MHNs) understanding, attitudes, empathy and confidence to work with people presenting with NSSI. ED and MHNs who belonged to either the College of Emergency Nursing Australasia (CENA) or the Australian College of Mental Health Nurses (ACMHN) were invited to complete an online survey through a group email from their college. One hundred and one nurses (56 ED and 45 MHNs) completed the survey. The results revealed that nurses from both groups had an accurate understanding of NSSI and had positive attitudes about patients who self‐injure. However, confidence was higher among MHNs. Greater knowledge of NSSI was correlated with increased confidence, positive attitudes and empathy. For mental health nurses, but not ED nurses, years of clinical practice was associated with nurses’ confidence. In contrast, ED nurses with more than 10 years’ experience were less confident in addressing NSSI than ED nurses with less experience. Issues that affect both ED and MHNs’ knowledge, attitude, empathy and confidence to care for patients who self‐injure are multifactorial. Future education and training should focus on therapeutic interactions with people at risk of repeat NSSI. Further, more research is recommended to explore patients’ perspectives of nurses’ attitudes in care for people who self‐injure.
Electromagnetic wave absorbing properties of Cr2AlB2 powders and the effect of high‐temperature oxidation
Authors: Zhang Haiming , Zhao Biao , Xiang Huimin , Dai Fu‐Zhi , Zhang Zhili , Zhou Yanchun
Published: December 2020

The electromagnetic (EM) wave absorbing properties of Cr2AlB2 powders and those after high‐temperature oxidation were investigated. Coupling of magnetic and dielectric loss enables Cr2AlB2 with good absorption properties. The minimum reflection loss (RL) value is −44.9 dB at 8.5 GHz with a thickness of 2.7 mm, and the optimized effective absorption bandwidth (EAB) is 4.4 GHz (13.0‐17.4 GHz) with a thickness of 1.6 mm. After oxidation at 750, 900, and 1000°C for 2 h, the minimum RL values, respectively, are −23.9 dB (17.5 GHz, 1.5 mm), −41.4 dB (16.5 GHz, 1.5 mm), and −39.5 dB (8.0 GHz, 3.0 mm); and the corresponding EAB values, respectively, are 3.8 GHz (13.6‐17.4 GHz, 1.7 mm), 4.1 GHz (13.5‐17.6 GHz, 1.6 mm), and 4.4 GHz (13.0‐17.4 GHz, 1.7 mm). With an absorber thickness of 1.5‐4.0 mm, the EAB with a RL value of less than −10 dB can be tuned in a broad‐frequency range 5.0‐18.0 GHz, which basically covers C (4‐8 GHz), X (8‐12 GHz), and Ku (12‐18 GHz) bands. These results demonstrate that Cr2AlB2, as a high‐efficient and oxidation‐resistant absorber, is a promising candidate for microwave absorption applications and can retain good EM wave absorbing properties after high‐temperature oxidation.
Lattice dynamics of yttria: A combined investigation from spectrum measurements and first‐principle calculations
Authors: Wang Chun‐Hai , Shu Wenhua , Qing Yuchang , Luo Fa , Zhu Dongmei , Zhou Wancheng
Published: December 2020

C‐type Y2O3 ceramics (relative density ~94%) were prepared at 1500 °C for 2 hours with 1% wt. ZnO as sintering aid. The cell parameters of Y2O3 from Rietveld refinements are a = 10.6113(1) Å, V = 1194.8(1) Å3. The vibrational modes / lattice dynamics of Y2O3 were investigated using vibrational spectra (Raman and infrared reflection spectra) and first‐principle (DFT) calculations. Eight of the 22 predicted first‐order Raman modes and 12 of 16 predicted IR modes are observed and reliably assigned. For the observed vibrational modes, an excellent linearity (fexp = 1.023ftheo, R2 = 0.9999) between frequency from calculations (ftheo) and that from measurements (fexp) is observed. Accordingly, the corrected frequency (fcor) of vibrational modes, phonon band structure, and density of phonon states (DOPS) of Y2O3 are presented, in which, the frequency of phonons of Y2O3 is ≤625.2 cm−1 (wavelength ≥16.0 μm) with a gap of 30.6 cm−1 from 486.0 to 516.6 cm−1 (wavelength 20.6 ‐ 19.4 μm) at room temperature. The modes with ftheo ≥292.5 cm−1 (fcor ≥299.2 cm−1) are dominated by the vibrations of O2− (light atom vibrations) and the vibrational modes with ftheo ≤239.0 cm−1 (fcor ≤244.5 cm−1) are dominated by the vibrations of both Y3+ and O2− (co‐vibrations). The three modes Tu(7) at 301.6 cm−1, Tu(10) at 333.7 cm−1, and Tu(12) at 369.7 cm−1 of Y‐O stretch vibrations dominate the phonon dielectric constant and dielectric loss of Y2O3 with more than 85% contributions.
An integrative review of empirical literature on indigenous cognitive impairment and dementia
Authors: Racine Louise , Johnson Letitia , Fowler‐Kerry Susan
Published: December 2020

Aims

To synthesize research findings about Indigenous perspectives on cognitive impairment and dementia.

Design

Whittemore and Knafl's updated approach to integrative review and PRISMA guidelines for narrative analysis was followed.

Data Sources

A systematic search of the published literature from 2010–June 2020 was undertaken in four databases and complemented by supplementary searches.

Review Methods

Thirty‐four studies met the research question and inclusion criteria.

Results

Four themes describe the findings. Most of the studies were conducted by non‐Indigenous researchers and may reflect Western perspectives on dementia rather than Indigenous views. A majority of the studies report epidemiological data or the testing of clinical tools.

Conclusion

The review indicates a dearth of knowledge about Indigenous perspectives on ageing and understanding of cognitive impairment and dementia. Researchers need to draw on Indigenous traditional knowledge, culture, and traditions through a meaningful engagement with Indigenous communities and Elders to indigenize and decolonize dementia care.

Impact

This integrative review highlights the need for community‐led discussions and community engagement around Indigenous perspectives, needs, and understandings of ageing, cognitive impairment, and dementia care.
Supine blood pressure—A clinically relevant determinant of vascular target organ damage in hypertensive patients
Authors: Nolde Janis M. , Kiuchi Márcio Galindo , Carnagarin Revathy , Frost Shaun , Kannenkeril Dennis , Lugo‐Gavidia Leslie Marisol , Chan Justine , Joyson Anu , Matthews Vance B. , Herat Lakshini Y. , Azzam Omar , Schlaich Markus P.
Published: December 2020

Night‐time blood pressure (BP) is an important predictor of cardiovascular outcomes. Its assessment, however, remains challenging due to limited accessibility to ambulatory BP devices in many settings, costs, and other factors. We hypothesized that BP measured in a supine position during daytime may perform similarly to night‐time BP when modeling their association with vascular hypertension‐mediated organ damage (HMOD). Data from 165 hypertensive patients were used who as part of their routine clinic workup had a series of standardized BP measurements including seated attended office, seated and supine unattended office, and ambulatory BP monitoring. HMOD was determined by assessment of kidney function and pulse wave velocity. Correlation analysis was carried out, and univariate and multivariate models were fitted to assess the extent of shared variance between the BP modalities and their individual and shared contribution to HMOD variables. Of all standard non‐24‐hour systolic BP assessments, supine systolic BP shared the highest degree of variance with systolic night‐time BP. In univariate analysis, both systolic supine and night‐time BP were strong determinants of HMOD variables. In multivariate models, supine BP outperformed night‐time BP as the most significant determinant of HMOD. These findings indicate that supine BP may not only be a clinically useful surrogate for night‐time BP when ambulatory BP monitoring is not available, but also highlights the possibility that unattended supine BP may be more closely related to HMOD than other BP measurement modalities, a proposition that requires further investigations in prospective studies.
Financial Fragility with SAM?
Authors: GREENWALD DANIEL L. , LANDVOIGT TIM , VAN NIEUWERBURGH STIJN
Published: December 2020

Shared appreciation mortgages (SAMs) feature mortgage payments that adjust with house prices. They are designed to stave off borrower default by providing payment relief when house prices fall. Some argue that SAMs may help prevent the next foreclosure crisis. However, home owners' gains from payment relief are mortgage lenders' losses. A general equilibrium model in which financial intermediaries channel savings from saver to borrower households shows that indexation of mortgage payments to aggregate house prices increases financial fragility, reduces risk‐sharing, and leads to expensive financial sector bailouts. In contrast, indexation to local house prices reduces financial fragility and improves risk‐sharing.
Teacher Experience, Personal Health, and Dieting Status Is Associated With Classroom Health‐Related Practices and Modeling*
Authors: Hamilton Lindsay , Goodman Lynnel , Roberts Lindsey , Dial Lauren A. , Pratt Mercedes , Musher‐Eizenman Dara
Published: December 2020

BACKGROUND

Evidence suggests that schools play an important role in student health; however, little is known about variability in teachers' use of food‐related classroom practices. In this study, we examined associations between teacher demographic and individual factors and their food‐related practices and modeling in the classroom.

METHODS

We had 239 teachers in the United States complete an online survey about their demographics (years of teaching experience, socioeconomic status of the school), personal health status, height and weight, and nutrition knowledge. Teachers also reported on the unhealthy food‐related practices they use in their classroom (eg, candy as a reward) and modeling (ie, engaging in unhealthy and healthy eating practices in front of students).

RESULTS

Hierarchical linear regressions were computed for each outcome separately. After controlling for socioeconomic status, fewer years of teaching experience and lower perception of personal health were associated with the use of unhealthy practices in the classroom. Teachers who were dieting were more likely to endorse healthy modeling.

CONCLUSIONS

Teacher demographic and individual factors are associated with food‐related classroom behavior. These findings have implications for interventions to promote the health of teachers and their students.
Organization of peptidoglycan synthesis in nodes and separate rings at different stages of cell division of Streptococcus pneumoniae
Authors: Perez Amilcar J. , Boersma Michael J. , Bruce Kevin E. , Lamanna Melissa M. , Shaw Sidney L. , Tsui Ho‐Ching T. , Taguchi Atsushi , Carlson Erin E. , VanNieuwenhze Michael S. , Winkler Malcolm E.
Published: December 2020

Bacterial peptidoglycan (PG) synthesis requires strict spatiotemporal organization to reproduce specific cell shapes. In ovoid‐shaped Streptococcus pneumoniae (Spn), septal and peripheral (elongation) PG synthesis occur simultaneously at midcell. To uncover the organization of proteins and activities that carry out these two modes of PG synthesis, we examined Spn cells vertically oriented onto their poles to image the division plane at the high lateral resolution of 3D‐SIM (structured‐illumination microscopy). Labeling with fluorescent D‐amino acids (FDAA) showed that areas of new transpeptidase (TP) activity catalyzed by penicillin‐binding proteins (PBPs) separate into a pair of concentric rings early in division, representing peripheral PG (pPG) synthesis (outer ring) and the leading‐edge (inner ring) of septal PG (sPG) synthesis. Fluorescently tagged PBP2x or FtsZ locate primarily to the inner FDAA‐marked ring, whereas PBP2b and FtsX remain in the outer ring, suggesting roles in sPG or pPG synthesis, respectively. Pulses of FDAA labeling revealed an arrangement of separate regularly spaced “nodes” of TP activity around the division site of predivisional cells. Tagged PBP2x, PBP2b, and FtsX proteins also exhibited nodal patterns with spacing comparable to that of FDAA labeling. Together, these results reveal new aspects of spatially ordered PG synthesis in ovococcal bacteria during cell division.
The utility of ultrasonography in anesthesia management in 3 cases of caudal regression syndrome
Authors: Ponde Vrushali Chandrashekhar , Desai Ankit Pankaj , Puranik Kiran Amey , Bosenberg Adrian , Chavan Dilip Namdev
Published: December 2020

Caudal regression syndrome is an extremely rare clinical entity. It is a challenge to anesthesiologist due to its multisystem involvement. Regional anesthesia literature on caudal regression syndrome is scarce. We report three cases where optimal use of ultrasonography aided in providing satisfactory peri‐operative pain relief. Furthermore, a cogent and a logical review of the decision‐making processes for the regional blockade in children with caudal regression syndrome are presented.
Medication interventions for African‐American adults: Practice‐based evidence from two nurse‐led clinics
Authors: Taani Murad H. , Ellis Julie L. , Zabler Bev , Kelber Sheryl T. , Tsai Pei‐Yun
Published: December 2020

Objective

This study was conducted to describe and examine the impact of medication intervention practices among African‐American clients in two nurse‐led community nursing centers (CNCs).

Methods

This study used a retrospective‐descriptive design. Omaha System data from visits of 196 African‐American adults living with chronic disease and having two or more CNC visits in which medication regimen was an identified problem and the main reason for the visit was analyzed.

Results

The sample had a mean age of 53.1 (6.67) and was primarily women (82%), uninsured, and with high school or less education. A total of 9,259 Medication regimen interventions were documented and implemented during 1,146 client CNC visits. A paired samples t test revealed statistically significant improvements in Knowledge (t = 2.434, p < .01). Behavior (t = 0.077, p = .94) and Status (t = 1.489, p = .14) remained unchanged, although the ratings trended toward improvement for each.

Conclusion

This study provides evidence that the nursing center model of care does improve the knowledge of medications among African‐American clients. The study also demonstrated the Omaha System's utility to evaluate the impact of nursing interventions in community settings.
Short interpregnancy interval and pregnancy outcomes: How important is the timing of confounding variable ascertainment?
Authors: Schummers Laura , Hutcheon Jennifer A. , Norman Wendy V. , Liauw Jessica , Bolatova Talshyn , Ahrens Katherine A.
Published: December 2020

Background

Estimation of causal effects of short interpregnancy interval on pregnancy outcomes may be confounded by time‐varying factors. These confounders should be ascertained at or before delivery of the first (“index”) pregnancy, but are often only measured at the subsequent pregnancy.

Objectives

To quantify bias induced by adjusting for time‐varying confounders ascertained at the subsequent (rather than the index) pregnancy in estimated effects of short interpregnancy interval on pregnancy outcomes.

Methods

We analysed linked records for births in British Columbia, Canada, 2004‐2014, to women with ≥2 singleton pregnancies (n = 121 151). We used log binomial regression to compare short (<6, 6‐11, 12‐17 months) to 18‐23‐month reference intervals for 5 outcomes: perinatal mortality (stillbirth and neonatal death); small for gestational age (SGA) birth and preterm delivery (all, early, spontaneous). We calculated per cent differences between adjusted risk ratios (aRR) from two models with maternal age, low socio‐economic status, body mass index, and smoking ascertained in the index pregnancy and the subsequent pregnancy. We considered relative per cent differences <5% minimal, 5%‐9% modest, and ≥10% substantial.

Results

Adjustment for confounders measured at the subsequent pregnancy introduced modest bias towards the null for perinatal mortality aRRs for <6‐month interpregnancy intervals [−9.7%, 95% confidence interval [CI] −15.3, −6.2). SGA aRRs were minimally biased towards the null (−1.1%, 95% CI −2.6, 0.8) for <6‐month intervals. While early preterm delivery aRRs were substantially biased towards the null (−10.4%, 95% CI −14.0, −6.6) for <6‐month interpregnancy intervals, bias was minimal for <6‐month intervals for all preterm deliveries (−0.6%, 95% CI −2.0, 0.8) and spontaneous preterm deliveries (−1.3%, 95% CI −3.1, 0.1). For all outcomes, bias was attenuated and minimal for 6‐11‐month and 12‐17‐month interpregnancy intervals.

Conclusion

These findings suggest that maternally linked pregnancy data may not be needed for appropriate confounder adjustment when studying the effects of short interpregnancy interval on pregnancy outcomes.
Do Legacy Industrial Sites Produce Legacy Effects in Ethnic and Racial Residential Settlement? Environmental Inequality Formation in Rhode Island’s Industrial Core1
Authors: Marlow Thomas , Frickel Scott , Elliott James R.
Published: December 2020

This study advances understanding of environmental inequality by examining its production through the interaction of two ubiquitous and ongoing urban‐ecological processes: industrial land‐use changes and changing patterns of residential segregation. We employ longitudinal data from the Rhode Island Directory of Manufacturers (1953–2012) and tract‐level US Census data measured at four panel‐years (1980, 1990, 2000, and 2010) to study the effects of these interactions in Rhode Island’s historical industrial cities of Providence, Pawtucket, and Central Falls. Spatial patterning analysis and hybrid spatial panel modeling of residential exposure to active and legacy industrial sites in relation to ongoing racial and industrial change reveal two novel findings. First, we find a “legacy effect,” suggesting that the spatial organization of industrial activities prior to the study period has measurable impacts on patterns of residential segregation in later decades. Our results also indicate that over the study period Latinx and African‐American residents have become increasingly less likely to bear disproportionate impacts of active manufacturing sites, despite very different spatial patterns of population growth. This is strong evidence that environmental inequality formation is a variable process in which historically distinct pathways can lead to similarly disproportionate exposure to environmental risk.
Among CMV‐positive renal transplant patients receiving non‐T‐cell depleting induction, the absence of CMV disease prevention is a safe strategy: A retrospective cohort of 372 patients
Authors: Boulay Hugoline , Oger Emmanuel , Cantarovich Diego , Gatault Philippe , Thierry Antoine , Le Meur Yannick , Duveau Agnès , Vigneau Cécile , Lorcy Nolwenn
Published: December 2020

Cytomegalovirus (CMV) is the most common opportunistic pathogen affecting renal transplant recipients, especially in the first months. CMV‐seropositive renal transplant recipients (CMV R+) are at intermediate risk for CMV disease, but this risk is enhanced among CMV R+ receiving T‐cell depleting induction, compared to CMV R+ receiving non‐depleting induction. In this second group, data in favor of prophylactic antiviral treatment with valganciclovir to reduce CMV disease is sparse. In this retrospective and multicentric trial, we included 372 CMV R+ transplanted between January 2012 and April 2015 and receiving non‐depleting induction. During the first year following transplantation, CMV disease occurred in 5/222 patients (2.25%) in the prophylaxis group and 9/150 (6%) in the no‐prophylaxis group (difference +3.7; 95% CI: 0.5‐8; P = .002 for non‐inferiority). The incidence of allograft rejection and other infectious diseases was similar between the two groups. Graft and patient survival were similar at the end of follow‐up. In conclusion, the absence of prophylaxis did not appear to have a deleterious effect for CMV diseases among CMV R+ receiving non‐depleting induction.
A Methodology to Characterize Modal Damping in Vibrating Systems: Application to the Case of Gas Turbine Combustion Chambers
Authors: Amedei Andrea , Meli Enrico , Rindi Andrea , Pucci Egidio
Published: December 2020

The present paper proposes a methodology to characterize the modal damping ratio as a function of frequency in vibrating systems, with a focus on gas turbine combustion chambers. Proposed methodology correlates the modal damping ratio to the system modal eigenfrequencies, accurately considering the damping physical effects on the system dynamics and goes beyond the standard proportional damping hypothesis and similar techniques present in the literature. The methodology has been compared under free-free conditions with standard damping ratio laws that can be found in the literature and which may lead sometimes to an overestimation of the real damping ratio values. Experimental data obtained through dedicated ping tests performed on two components of an industrial gas turbine annular combustion chamber have been used for the methodology validation: comparison between simulated and experimental results seems to be encouraging and the proposed methodology for modal damping ratio characterization turns out to be better, with respect to the standard ones, in reproducing not only the experimentally estimated damping law (as a function of the frequency), but also the typical Force Response Functions (FRFs) of the considered vibrating systems. Finally, since the adopted procedure is numerically efficient and based only on low cost experimental techniques, it can be used for describing modal damping in vibrating systems since the early phases of the design, by increasing the design accuracy and reducing times and costs.
Pilot studies on zebrafish echocardiography and zebrafish ultrasound vibro-elastography
Authors: Zhang Xiaoming , Zhang Alex , Xu Xiaolei
Published: December 2020

Zebrafish are being increasingly used as animal models for human diseases such as cardiomyopathy and neuroblastoma because zebrafish have a nearly fully sequenced genome to humans. One pilot study is to develop zebrafish echocardiography. Because the heart of a zebrafish is small, a high frequency ultrasound system (50–80 MHz) is used for imaging. B-Mode imaging is analyzed for quantification of ejection fraction (EF), end-systolic volume (ESV), and end-diastolic volume (EDV). Pulse-wave Doppler (PWD) is used to calculate the E/A ratio (the peak velocities of E and A waves) and myocardial performance index (MPI). Techniques for improving image quality and repeatability of zebrafish echocardiography are discussed. Another pilot study is to develop zebrafish ultrasound vibro-elastography (ZUVE) for measuring the elastic properties of zebrafish. An adult female zebrafish is anesthetized for 3 min. A 0.1-s gentle harmonic vibration is generated on the tail of a zebrafish using a sphere tip indenter with a 3 mm diameter. Shear wave propagation in the zebrafish is measured using a high frequency 18 MHz ultrasound linear array probe. We conclude that ZUVE is safe, fast, and noninvasive and feasible for testing the elastic properties of zebrafish.
Sensitivity study of the acoustic parameters on the wave transmitted through a bilayer porous medium at very low frequencies
Authors: Sadouki Mustapha , Rahmoun Nassiba , Boudani Kenza
Published: December 2020

The objective of this work is to present a sensitivity study of very low frequency parameters on waves transmitted through a bilayer medium made of two different layers of a porous medium saturated with air. The equivalent fluid theory is considered. Viscous-inertial and thermal effects are taken into account by the dynamic tortuosity and dynamic compressibility given by the Johnson-Champoux-Allard (JCA) model. At very low frequencies, the dynamic tortuosity and compressibility depend only on the porosity and air flow resistivity. An expression of the transmission coefficient of a bilayer medium has been established in the frequency regime. This expression depends on the porosity and resistivity of each layer. The influence of the Â±20% variation in these parameters on the transmitted signal was presented and discussed. This study was done in the frequency domain as well as in the time domain.
Virtual reality based assessment and education tool for auditory hallucination symptoms
Authors: Won Junseok , Lee Kounseok , Jeon Jin Yong
Published: December 2020

This study proposes a method to overcome the limitations of existing tests used to evaluate the symptoms of hallucinations in patients with schizophrenia. Moreover, it aimed to verify whether the disruption to daily life caused by hallucinations can be alleviated by performing a continuous attention task. To verify this, 44 patients with schizophrenia who experienced hallucinations and 22 general control groups were recruited. The patients were randomly assigned to the experimental group and patient control condition, and healthy people were assigned to the normal control condition. The experiment consisted of a total of six sessions: a pretest, four tests, and later tests. The experiment involved a 2-back task and auditory perception recognition, and only the experimental group and patient control group were provided with psychological education. The results of this study confirmed that hallucinations influenced the deterioration of attention-focused tasks. Furthermore, it was confirmed that the interference effect due to hearing loss was reduced by repeating the 2-back task and auditory recognition evaluation. Thus, the proposed hallucination evaluation and education method was effective in objectively evaluating hallucinations and reducing the disruption caused by hallucinations. In addition, the limitations of this study and suggestions for follow-up studies were presented.
Modeling and estimation with multiple reflections
Authors: Alkhairy Samiya
Published: December 2020

When medium property variation is not smooth and slow or perturbative, multiple reflections are non-negligible. We model multiples and develop associated methods for estimating medium parameters from received signals. We focus on 1-D which is fundamental theoretically and has direct applications to layered media, e.g., nondestructive testing for delamination in layered composites. We account for all reflection multiples: intra and inter-layer including sub and supra-source layer multiples. We represent the system in two ways, and develop associated model expressions and estimation methods. For the block diagram representation, we employ system functionals to develop closed-from expressions of the transfer function that do not require integration. Using this expression, we can estimate parameters by optimization. For the tree-diagram representation, we develop expressions that construct the response semi-incrementally in time. We develop non-optimization-based methods to estimate parameters from theseexpressions without prior knowledge of the number of layers. For broad-band signals, this method runs in real-time. Our models and methodsaccount for various multiples, are easily modifiable for various configurations (of pre-source layers and location of source-receiver) and source radiation patterns (uni/bi-directionality). Configurational flexibility, diagrammatic representations, simple closed-form expression, interpretable models, and form of estimation methods are strengths of our models and methods.
Nonlinear harmonic imaging of solids
Authors: Huanes-Alvan Guillermo E. , Chakrapani Sunil Kishore
Published: December 2020

Nonlinear ultrasonics has been shown to be sensitive to small scale damage and microstructural changes in solids. However, measuring the nonlinearity parameter of a solid requires complex calibrations and point-by-point measurements using contact transducers. This poses a challenge when it comes to applying this technique for imaging. The present work explores the use of immersion based nonlinear ultrasonics to perform nonlinear harmonic imaging of solids. A solid sample immersed in liquid (water) will form a “3-layer” structures (water-solid-water) when two ultrasonics transducers are used in through transmission mode. This work will explore the analytical modeling of such a structure using the KZK equation to model the combined effect of attenuation and diffraction of the three layers. The objective of the modelling effort is to develop an inversion model to invert the acoustic nonlinearity parameter from experimental results. The nonlinear model was further validated using experimental measurements carried out on a Steel sample with localized damaged.
Numerical study on evolution of weakly nonlinear waves into an acoustic soliton in bubbly water
Authors: Ayukai Takahiro , Kanagawa Tetsuya
Published: December 2020

Finite but small amplitude (i.e., weakly nonlinear) propagation of pressure (or acoustic) waves in an initially quiescent water uniformly containing many spherical microbubbles is numerically studied. Especially, an effective equation for the case of low frequency long wave is the Korteweg–de Vries–Burgers (KdVB) equation, which consists of the nonlinear, dissipation, and dispersion terms. Two major solutions of KdVB equation are a shock wave (i.e., dissipative case) and a soliton (i.e., dispersive case). The purpose of this study is the elucidation of spatio-temporal evolution of these three terms (not coefficients) and that of resultant waveforms. The results are summarized as follows: (a) a solitary pulse waves were formed by the nonlinear and dispersion terms and well-known nonlinear interaction was observed; (b) the number of formed solitons was dependent on the initial waveform such as Gaussian, shock, and rectangular waveforms; (c) the number of formed solitons was strongly dependent on the initial void fraction.
Effective metamaterial properties for non-local active acoustic media
Authors: Geib Nathan , Sasmal Aritra , Popa Bogdan-Ioan , Grosh Karl
Published: December 2020

Acoustic metamaterials are generally composed of complex arrays of subwavelength unit cells that can be cumbersome to analyze and simulate. Consequently, it is common practice to approximate metamaterials as homogeneous media with unique material properties, most commonly negative or near-zero density, negative or near-zero bulk modulus, or both negative or near-zero density and bulk modulus. In addition to easing the computational burden associated with complex metamaterial structures, effective material properties can provide deeper understanding of system behavior, providing additional insight and tools in the development of acoustic metamaterials. Here, we present a method for determining effective material properties for a non-local, active acoustic metamaterial. We contrast these properties with those typically associated with acoustic metamaterials and discuss how such properties are characteristic of a new class of acoustic metamaterials.
Ray and beam tracing in underwater acoustics
Authors: Porter Michael B.
Published: December 2020

In 1919, Lichte published a paper on the influence of horizontal temperatures layers in sea water (his words). This paper is probably the first to use rays to understand sound propagation in the ocean and interestingly also predicts that deep water will provide “significantly greater ranges than in shallow water” anticipating later important discoveries about the deep-water sound channel. It is striking that ray modeling could be done in 1919. In the 1960s when digital computers assumed their central role in sound propagation, ray models were the inspiration. Over the following years many ray models were developed and every significant laboratory doing underwater acoustics had developed one. However, ray modeling is simple on one level, yet incredibly complex on others. A Navy report from 1985 concluded that they all had significant problems. In the following 30-odd years, other modeling approaches were pursued more aggressively; however, ray models had unique advantages and continued to evolve into modern beam-tracing methods. These new models are not free from the artifacts inherent in the ray approximation, but nevertheless are very powerful and significantly more accurate and reliable than their ancestors. Today they work. This talk will discuss the history and the state of the art.
Comparison of ray tracing to energy flux for computing transmission loss in uncertain environments
Authors: Martinelli Sheri
Published: December 2020

The Lagrangian nature of the ray tracing equations imparts a known sensitivity of solutions to initial conditions for long integration times. Yet ray models remain a standard for high frequency wave propagation due to their computational efficiency and amenability to parallelization. Acoustic energy flux methods can provide an alternative solution in the high frequency regime when a large number of propagating modes are closely spaced in angle. The energy flux approach has also been shown to be quite robust to variability in bathymetry and sediment type in underwater applications. In this work, we apply generalized polynomial chaos expansions to represent both an acoustic ray model and an acoustic energy flux model in identical underwater environments in which the sound speed profile, source depth, and bathymetry are uncertain and thus modeled by random quantities. The output quantity of interest is taken to be the coherent (semi-coherent in the case of energy flux) transmission loss as a function of range and depth. Comparisons are made through assessment of the statistical moments of the output, and a sensitivity study on the uncertain parameters.
Forty-one years of responding to external stimuli: Elliott Berger's career in hearing conservation
Authors: Fackler Cameron J. , Hamer Jeffrey L.
Published: December 2020

It was 1976, hearing conservation and earplug technology had just been advanced by the introduction of the first slow-recovery roll-down foam earplug four years ago, and Elliott Berger had just entered the workforce. Over the next 41 years, Elliott would be a key player in many other advancements in hearing conservation. This paper will briefly summarize his career and contributions to hearing conservation, including research and development of new hearing protectors, standardization of many aspects of hearing conservation, and education of hearing conservation practitioners. Along the way, Elliott documented his work in numerous journal articles, book chapters, and presentations. Several of Elliott's colleagues, collaborators, and friends are here today to fill in more of the details of his career and work to advance hearing conservation.
Solving the cocktail party problem for bilateral cochlear implant users
Authors: Brown Christopher A.
Published: December 2020

It is well-known that listeners with hearing impairment have trouble solving the cocktail party problem. Bilateral cochlear implant users have shown little or no perceptual abilities in this regard. This is due in large part to poor encoding of interaural time difference cues by these devices. Interaural level difference cues, which are well-encoded by bilateral cochlear implants, are not thought to facilitate benefit beyond improved signal-to-noise ratio benefits from head-shadow. An approach to mitigating this problem will be presented, that magnifies interaural level difference cues in real time to increase the perceptual distance between sound sources that are separated in the horizontal plane. The effects of ILD magnification on source localization and speech intelligibility in cocktail-party settings will be discussed.
Metamaterial-based acoustic camera enhancements
Authors: Eccles Jonathan , Cobden Robert , Pouryazdan Arash , Memoli Gianluca
Published: December 2020

Acoustic cameras are a common approach to solving the challenge of sound localisation in non-destructive testing. The required microphone arrays, however, are often cumbersome: a large number of sensors is needed to achieve the required accuracy and their mutual distances need to be maximized to increase spatial resolution. Current acoustic cameras are not easily portable. In this work, we explore whether acoustic metamaterials can be used to create compact acoustic cameras, complete of autozoom objectives. We present our proof-of-concept prototype, comprising 8 MEMS microphones, using beamforming algorithms now sufficiently simple to run on a Raspberry Pi. We discuss how the performance changes when passing from a single lens to a two-lenses objective. Finally, we highlight the perspectives, the limitations and some key user scenarios for this approach.
Using auditory electrophysiology testing to define the high frequencies across non-human mammal species
Authors: Bielefeld Eric , DeBacker J. R.
Published: December 2020

While the human's frequency range of audibility has been well documented at 20–20 000 Hz, the audible frequency ranges vary considerably from species to species. As such, that which constitutes the “high-frequency” range is quite different in mice, rats, guinea pigs, gerbils, chinchillas, and cats. These mammalian species have been frequently used in anatomical and physiological investigations of the peripheral and central auditory nervous systems. Much of what we know about the physiology of the auditory system is based upon on these animal species, yet many of their auditory systems operate in a much different frequency range from the human's. We will discuss the use of auditory electrophysiology to define the high-frequency ranges across several different mammal species, and then transition to a comparison of their high-frequency ranges to that of the human. Further, we will discuss the implications of trying to extrapolate insight into human auditory physiology from animal species whose high-frequency ranges are quite different from our own.
Artificial bandwidth extension of speech signals
Authors: Vary Peter , Schlien Thomas
Published: December 2020

Artificial Bandwidth Extension (ABWE) algorithms try to reconstruct frequency components of speech signals which have been lost by coding/transmission. From a system theoretical point of view, this seems to be questionable. However, by exploiting redundancy of speech production as well as psychoacoustic properties of auditory perception, missing parts can subjectively be recovered or at least mimicked to a certain extent. The motivation for ABWE is to bridge the quality gap between the traditional narrowband telephony (200–3400 Hz) and the recent wideband services (HD voice, 50–7000 Hz). An HD terminal which is connected to a traditional phone, may activate ABWE for improving the audio quality and possibly the intelligibility of the received signal. In this contribution, state-of-the-art ABWE algorithms and coding standards including ABWE techniques are reviewed. ABWE algorithms are based on a source-filter model. The three main sub-tasks are to estimate the excitation signal, the spectral envelope and the time domain envelope, given either just the narrowband signal or in addition a few bits of side information. Furthermore, insights with respect to the relative importance of these three components are presented.
The importance of high-frequency hearing in a medico-legal context
Authors: Moore Brian C.
Published: December 2020

People whose hearing is damaged by exposure to intense sounds, typically in noisy factories or during military service, often claim compensation. The most common complaint of such people is difficulty in understanding speech when background sounds are present. However, because direct measures of the intelligibility if speech in noise were perceived to be unreliable, compensation has traditionally been based on the audiogram. Exposure to intense sounds usually has its greatest effects on audiometric thresholds at 4, 6, and 8 kHz. However, in several countries, including the USA and the UK, compensation for occupational noise-induced hearing loss is usually calculated using the average of audiometric thresholds for selected frequencies up to 3 kHz, based on the implicit assumption that hearing loss for frequencies above 3 kHz has no material adverse consequences. In fact, several studies show that frequencies above 3 kHz are important for the perception of speech in background sounds and for sound localisation, especially for resolving front-back confusions. It is concluded that audiometric thresholds at 4 kHz and perhaps 6 kHz should be taken into account when assessing hearing in a medico-legal context. In addition, direct measures of the ability to understand speech in noise should be obtained.
Characterization of particle motion near offshore wind farm sites in the United States east coast
Authors: Potty Gopu R. , Miller James H. , Lin Ying T. , Newhall Arthur E.
Published: December 2020

This study analyzes the particle motion data recorded on geophones and ocean bottom seismometers (OBXs) at various shallow water (water depth ∼30 m) locations in the U.S. east coast near offshore wind farms. The Block Island, Rhode Island site was the location of the first offshore wind farm in the United States. Data were collected at this site during three different deployments in 2015, 2016, and 2017. Particle motion measurements were made during construction and operation of the wind turbines during these deployments. Data collected on a 3-axis geophone will be discussed in this study. This sensor package included a 3-axis geophone and a co-located hydrophone. This 3-axis geophone measured the particle motion (particle velocity) in three mutually perpendicular directions along with acoustic pressure. The same sensor package was also deployed ten miles east of Ocean City, Maryland and near the Virginia wind farm. During this deployment, in addition to the geophone package, four Ocean Bottom Recorders (OBXs) were also deployed as a line array to record construction noise. Data from these deployments will be presented and compared with published data from other windfarm sites. [Work supported by the U.S. Department of the Interior, Bureau of Ocean Energy Management (BOEM), Environmental Studies Program]
Impacts of range-dependent bottom type on mid-frequency propagation
Authors: Hefner Brian T. , Tang Dajun
Published: December 2020

The Target and Reverberation Experiment in 2013 (TREX13) focused on mid-frequency propagation and reverberation in shallow water off the coast of Panama City Beach, FL. The seafloor at the site primarily consisted of long-wavelength (150–200 m), small-amplitude (∼1 m) sand ridges with narrow (20–30 m wide) regions of mud in the swales. Backscatter measurements using a multibeam sonar indicated that roughly 10%–20% of the seafloor was covered in mud. During the experiment, a source transmitting tones from 1.5 to 4.0 kHz was towed past two stationary vertical line arrays to measure the transmission loss (TL) along the track. The measured TL was found to be midway between the predictions for pure sand and puremud sediments, despite the limited amount of mud at the site. Range-dependent propagation models which incorporate this variation in sediment type, indicate that the mud regions act as sinks of acoustic energy producing a significant increase in loss. Also, the spatial distribution is such that the mud regions cannot be discerned in the TL range-dependence. The implications of this range-dependence on both inversion and reverberation will be discussed. [Work supported by the U.S. Office of Naval Research.]
Impact of the Chicago soundscape on building envelope design
Authors: Catton Anna C. , Sevener Nathan
Published: December 2020

Chicago's unique soundscape, dominated by buses and other street traffic, commuter trains, and the City's signature “L,” both driven and augmented by the dense development in the urban core and preponderance of high-rise buildings, places demands on building envelope design. Building envelope design must address noise isolation at the fac¸ade of the structure and the frequent use of extensive glazing means that noise isolation has particularly large cost implications. Through measurements and acoustic modeling, the sound level can be quantified and predicted over the fac¸ade of a building under design. The results advise the envelope assemblies and acoustical design goals. This presentation will provide examples of the sound levels measured at various locations around the City, illustrate acoustic modeling that has been used to predict noise levels over the building fac¸ades under design, and describe envelope assemblies and acoustical design criteria that have been used.