Signal power distributions for simulated outdoor sound propagation in varying refractive conditions.

Probability distributions of acoustic signals propagating through the near-ground atmosphere are simulated by the parabolic equation method. The simulations involve propagation at four angles relative to the mean wind, with frequencies of 100, 200, 400, and 800 Hz. The environmental representation includes realistic atmospheric refractive profiles, turbulence, and ground interactions; cases are considered with and without parametric uncertainties in the wind velocity and surface heat flux.

Comprehensive compartmental model and calibration algorithm for the study of clinical implications of the population-level spread of COVID-19: a study protocol.

Introduction: The complex dynamics of the coronavirus disease 2019 (COVID-19) pandemic has made obtaining reliable long-term forecasts of the disease progression difficult. Simple mechanistic models with deterministic parameters are useful for short-term predictions but have ultimately been unsuccessful in extrapolating the trajectory of the pandemic because of unmodelled dynamics and the unrealistic level of certainty that is assumed in the predictions.

Methods And Analysis: We propose a 22-compartment epidemiological model that includes compartments not previously considered concurrently, to account for the effects of vaccination, asymptomatic individuals, inadequate access to hospital care, post-acute COVID-19 and recovery with long-term health complications.

Exploring the potential for planning support systems to bridge the research-translation gap between public health and urban planning.

Background: There is consensus that planning professionals need clearer guidance on the features that are likely to produce optimal community-wide health benefits. However, much of this evidence resides in academic literature and not in tools accessible to the diverse group of professionals shaping our cities. Incorporating health-related metrics into the planning support systems (PSS) provides an opportunity to apply empirical evidence on built environment relationships with health-related outcomes to inform real-world land use and transportation planning decisions.

Machine-learning of long-range sound propagation through simulated atmospheric turbulence.

Conventional numerical methods can capture the inherent variability of long-range outdoor sound propagation. However, computational memory and time requirements are high. In contrast, machine-learning models provide very fast predictions.

Distribution of the two-point product of complex amplitudes in the fully saturated scattering regime.

This Letter considers probability density functions (pdfs) involving products of the complex amplitudes observed at two points (which may, in general, involve separations in space, time, or frequency) in conditions of fully saturated scattering. First, the pdf is derived for the product of the complex amplitude at one point with the conjugate of the complex amplitude at another point. It is shown that the real and imaginary parts of this product each have a variance gamma pdf.

Multilevel modeling and regression of community annoyance to transportation noise.

A multilevel (hierarchical) model is devised that separates noise tolerance into variations occurring at the levels of individual listeners and communities. This approach successfully describes the characteristics of real community transportation noise surveys, with the individual- and community-level variations producing distinct statistical signatures, both of which are evident in the surveys. Predictions are provided for quantities such as the probability of annoyance based on the observed noise level and statistical parameters characterizing the community tolerance.

Outcomes following emergent open repair for thoracic aortic dissection are improved at higher volume centers in direct admissions and transfers.

Background: The purpose of this study is (1) to define the proportion of patients undergoing emergent open repair of thoracic aortic dissection admitted directly through the emergency room versus those transferred from outside hospitals and (2) to determine if a volume-outcomes relationship exists for those patients across admission types.

Methods: De-identified patient-level data was obtained from the Nationwide Inpatient Sample (2004-2008). Patients undergoing emergent aortic surgery for thoracic aortic dissection (n = 1,507) were identified by ICD-9 codes and stratified by annual center volume into low volume (≤5 cases/year) (n = 963; 63.

Comparisons between physics-based, engineering, and statistical learning models for outdoor sound propagation.

Many outdoor sound propagation models exist, ranging from highly complex physics-based simulations to simplified engineering calculations, and more recently, highly flexible statistical learning methods. Several engineering and statistical learning models are evaluated by using a particular physics-based model, namely, a Crank-Nicholson parabolic equation (CNPE), as a benchmark. Narrowband transmission loss values predicted with the CNPE, based upon a simulated data set of meteorological, boundary, and source conditions, act as simulated observations.

Utilizing intentional internal resonance to achieve multi-harmonic atomic force microscopy.

During dynamic atomic force microscopy (AFM), the deflection of a scanning cantilever generates multiple frequency terms due to the nonlinear nature of AFM tip-sample interactions. Even though each frequency term is reasonably expected to encode information about the sample, only the fundamental frequency term is typically decoded to provide topographic mapping of the measured surface. One of main reasons for discarding higher harmonic signals is their low signal-to-noise ratio.

The impact of age and severity of comorbid illness on outcomes after isolated aortic valve replacement for aortic stenosis.

Objectives: This study examines outcomes in a national sample of patients undergoing isolated aortic valve replacement (AVR) for aortic stenosis, with particular focus on advanced-age patients and those with extreme severity of comorbid illness (SOI).

Methods: Data were obtained from the Nationwide Inpatient Sample and included all patients undergoing AVRs performed from January 1, 2006 to December 31, 2008. Patients with major concomitant cardiac procedures, as well as those aged, 20 years, and those with infective endocarditis or aortic insufficiency without aortic stenosis, were excluded from analysis.

Description and quantification of uncertainty in outdoor sound propagation calculations.

The accuracy of outdoor sound propagation predictions is often limited by imperfect knowledge of the atmospheric and ground properties, and random environmental variations such as turbulence. This article describes the impact of such uncertainties, and how they can be efficiently addressed and quantified with stochastic sampling techniques such as Monte Carlo and Latin hypercube sampling (LHS). Extensions to these techniques, such as importance sampling based on simpler, more efficient propagation models, and adaptive importance sampling, are described.

Reconnecting urban planning with health: a protocol for the development and validation of national liveability indicators associated with noncommunicable disease risk behaviours and health outcomes.

Aim: Liveable communities create the conditions to optimise health and wellbeing outcomes in residents by influencing various social determinants of health - for example, neighbourhood walkability and access to public transport, public open space, local amenities, and social and community facilities. This study will develop national liveability indicators that are (a) aligned with state and federal urban policy, (b) developed using national data (where available), (c) standard and consistent over time, (d) suitable for monitoring progress towards creating more liveable, equitable and sustainable communities, (e) validated against selected noncommunicable disease risk behaviours and/or health outcomes, and (f) practical for measuring local, national and federal built environment interventions.

Study Type: Protocol.

Information-criterion based selection of models for community noise annoyance.

Statistical evidence for various models relating day-night sound level (DNL) to community noise annoyance is assessed with the Akaike information criterion. In particular, community-specific adjustments such as the community tolerance level (CTL, the DNL at which 50% of survey respondents are highly annoyed) and community tolerance spread (CTS, the difference between the DNL at which 90% and 10% are highly annoyed) are considered. The results strongly support models characterizing annoyance on a community-by-community basis, rather than with complete pooling and analysis of all available surveys.

Proper orthogonal decomposition and cluster weighted modeling for sensitivity analysis of sound propagation in the atmospheric surface layer.

Outdoor sound propagation predictions are compromised by uncertainty and error in the atmosphere and terrain representations, and sometimes also by simplified or incorrect physics. A model's predictive power, i.e.

Characterization of uncertainty in outdoor sound propagation predictions.

Predictive skill for outdoor sound propagation is assessed using high-resolution atmospheric fields from large-eddy simulations (LES). Propagation calculations through the full LES fields are compared to calculations through subsets of the LES fields that have been processed in typical ways, such as mean vertical profiles and instantaneous vertical profiles synchronized to the sound propagation. It is found that mean sound pressure levels can be predicted with low errors from the mean profiles, except in refractive shadow regions.