Elevated Noise Levels Research Articles

Epidemiology of Health Concerns Among Collegiate Student Musicians Participating in Marching Band

Participation in marching band requires intense physical and mental requirements, altered and potentially elevated biomechanical demands related to performing musical instruments while marching, routine exposures to elevated noise levels and at times hazardous weather conditions, and time commitments for practice and travel. Unfortunately, there are no known epidemiologic studies that systematically examine the perception of health-related consequences among college students participating in a collegiate marching band. There are no known studies that attempt to understand if the perceived consequences of marching band are different for students majoring in music compared to non-music major students. In response to this deficiency, this study collected and characterized occupational health patterns and concerns associated with participation in a collegiate marching band. Members of a large collegiate marching band (n=246/310, 76%) responded to a 70-item epidemiologic survey. Results reveal patterns of health concerns and how they differ when compared across music majors vs non-music majors and instrument groups.

Contribution of iceberg sounds to the ambient noise budget in the South Pacific Ocean

On May 2002, C19, a 5500 km2 iceberg calved from the Ross Ice Shelf, eventually drifting eastward into the open Pacific Ocean by 2008. As it sailed into warmer waters, thermal and wind stresses caused the iceberg to crack and break apart. These resulting “icequakes” projected wideband acoustic energy into the water column, influencing the regional ambient noise environment. Icequake noise was persistent and strong enough to be observed by NOAA’s eastern equatorial Pacific moored hydrophone (EEP-NW at 8N, 110W) as well as the hydroacoustic station of International Monitoring System (IMS) on Juan Fernandez Island (H03N at 33.44S, 78.91W). Elevated noise levels (maximum of ~+3 dB at NOAA’s EEP and ~+7 dB at IMS H03N hydrophones) were observed by both stations from early 2008 when C19a first appeared in the Pacific until it drifted into the Atlantic Ocean in early 2009. C19a’s icequake and calving activity was also most frequent during this same period. Seasonal changes and long-term trends in ambient noise levels at NOAA’s EEP-NW acoustic mooring (1996–2009) and IMS Juan Fernandez (2003–2010 years) and the unique acoustic role icebergs play in the Southern Ocean will be presented.

Microseismic Monitoring of CO2 Injection at the Penn West Enhanced Oil Recovery Pilot Project, Canada: Implications for Detection of Wellbore Leakage

A passive seismic monitoring campaign was carried out in the frame of a CO2-Enhanced Oil Recovery (EOR) pilot project in Alberta, Canada. Our analysis focuses on a two-week period during which prominent downhole pressure fluctuations in the reservoir were accompanied by a leakage of CO2 and CH4 along the monitoring well equipped with an array of short-period borehole geophones. We applied state of the art seismological processing schemes to the continuous seismic waveform recordings. During the analyzed time period we did not find evidence of induced micro-seismicity associated with CO2 injection. Instead, we identified signals related to the leakage of CO2 and CH4, in that seven out of the eight geophones show a clearly elevated noise level framing the onset time of leakage along the monitoring well. Our results confirm that micro-seismic monitoring of reservoir treatment can contribute towards improved reservoir monitoring and leakage detection.

387 Exposure to particles and noise during highway maintenance work and associated short-term cardiovascular health effects

ObjectivesHighway maintenance workers are exposed to elevated particle and noise levels during their work. Exposure to particles as well as to noise has been linked to cardiovascular diseases. Thus, this...

Equivalent Intrinsic Noise, Sampling Efficiency, and Contrast Sensitivity in Patients With Retinitis Pigmentosa

To determine the relationships among equivalent intrinsic noise (Neq), sampling efficiency, and contrast sensitivity (CS) in patients with retinitis pigmentosa (RP), where Neq is an estimate of the amount of noise within the visual pathway and sampling efficiency represents the subject's ability to use stimulus information optimally. Participants included 10 patients with RP aged 10 to 54 years, who had visual acuities of 20/40 or better, and 10 visually normal control subjects aged 22 to 65 years. CS was measured for 2-cycles-per-degree Gabor patch targets presented in the absence of noise (CS0) and in five levels of noise spectral density. Data were fit with a standard linear amplifier model, which provided estimates of Neq and sampling efficiency. CS0 for the patients ranged from normal to as much as a factor of 3 below the lower limit of normal. All 10 patients had abnormally high Neq, including two patients with normal CS0. In comparison, only two patients had lower-than-normal sampling efficiency, and these two patients also had below-normal CS0. Log CS0 for the patients was correlated significantly with log Neq (r = -0.80, P < 0.05), but not with log efficiency (r = 0.54, P = 0.11). Low CS was associated with elevated intrinsic noise in this group of RP patients, but even patients with normal CS had elevated noise levels. The results suggest that CS measurement in both the presence and absence of luminance noise can provide important information about visual dysfunction in RP patients.

Exposure of Highway Maintenance Workers to Fine Particulate Matter and Noise

In this study, we assessed the mixed exposure of highway maintenance workers to airborne particles, noise, and gaseous co-pollutants. The aim was to provide a better understanding of the workers' exposure to facilitate the evaluation of short-term effects on cardiovascular health endpoints. To quantify the workers' exposure, we monitored 18 subjects during 50 non-consecutive work shifts. Exposure assessment was based on personal and work site measurements and included fine particulate matter (PM2.5), particle number concentration (PNC), noise (Leq), and the gaseous co-pollutants: carbon monoxide, nitrogen dioxide, and ozone. Mean work shift PM2.5 concentrations (gravimetric measurements) ranged from 20.3 to 321 μg m(-3) (mean 62 μg m(-3)) and PNC were between 1.6×10(4) and 4.1×10(5) particles cm(-3) (8.9×10(4) particles cm(-3)). Noise levels were generally high with Leq over work shifts from 73.3 to 96.0 dB(A); the averaged Leq over all work shifts was 87.2 dB(A). The highest exposure to fine and ultrafine particles was measured during grass mowing and lumbering when motorized brush cutters and chain saws were used. Highest noise levels, caused by pneumatic hammers, were measured during paving and guardrail repair. We found moderate Spearman correlations between PNC and PM2.5 (r = 0.56); PNC, PM2.5, and CO (r = 0.60 and r = 0.50) as well as PNC and noise (r = 0.50). Variability and correlation of parameters were influenced by work activities that included equipment causing combined air pollutant and noise emissions (e.g. brush cutters and chain saws). We conclude that highway maintenance workers are frequently exposed to elevated airborne particle and noise levels compared with the average population. This elevated exposure is a consequence of the permanent proximity to highway traffic with additional peak exposures caused by emissions of the work-related equipment.

Quantifying the ambient community noise environment for optimal industry siting

A road traffic noise model was developed to approximate the ambient noise levels present within a 200 km2 urban center. Road corridors that included highways, city streets, and country side-roads with varying traffic volumes were modeled to evaluate the existing ambient conditions within the project area. To calculate noise levels, an acoustical model and Traffic Noise Model (TNM) calculation standard was used to account for a variety of real-world variables such as daily average traffic counts, turning counts, speed limits, road composition, elevation, road width, and traffic composition. The model generated noise contours that were used to identify areas of elevated ambient noise levels within the project area that may prove suitable for a medium-sized industrial facility. This modeling technique and ambient community noise analysis allowed for the identification of an optimal site within the project area and also proved to be an approach that can be used to industry’s advantage. Urban noise is an emerging issue for growing communities. Locating new facilities within urbanized areas with elevated ambient conditions may minimize community noise impacts, reduce post-construction noise abatement costs, and ultimately promote complementary adjacent land use and sustainable urban densification.

Songs of the city: noise-dependent spectral plasticity in the acoustic phenotype of urban birds

Urbanization leads to homogenization of avian communities through local extinction of rare bird species and increasing numbers of the same common urban bird species over large geographical areas. Successful city birds often persist through some sort of behavioural plasticity that helps them survive and reproduce close to humans, in built-up areas, with all the typical urban feasts and hazards. In this review, I address whether behavioural plasticity of the acoustic phenotype can be an additional factor in explaining which species end up as urban survivors. Anthropogenic noise has been shown to negatively affect avian distribution and reproduction, especially for species that rely on relatively low-frequency songs for mediating territorial conflicts and attracting partners for mating. Spectral differences between songs of city and forest populations of the same species and correlations between individual song frequency use and local noise levels suggest that many successful city species shift song frequency upward under noisy urban conditions. Experimental evidence has confirmed the ability of several species to show rapid spectral adjustments as well as perceptual benefits of singing at higher frequency in noisy habitats. However, empirical evidence of fitness benefits for birds showing the ability and tendency of noise-dependent spectral adjustment is still lacking. Furthermore, depending on the species and the underlying mechanism for spectral change, there may also be fitness costs through a compromise on signal function. These two aspects are only two of many remaining avenues for future studies. The acoustic phenotype of urban birds provides a great model system to study fundamental processes such as causes and consequences of environmentally induced signal changes, ‘cultural assimilation’, and the relationship between phenotypic and genotypic evolution. Furthermore, the current and expected rate of urbanization remains high at a global scale, which will lead to further spread in time and space of artificially elevated noise levels. This should guarantee the continued interest of scientists, politicians and conservationists for many years ahead.

Staying tuned: grasshoppers from noisy roadside habitats produce courtship signals with elevated frequency components

Summary Anthropogenic noise is known to affect acoustic signal production in birds, frogs and mammals. These animals use different mechanisms to adjust their signals to elevated background noise levels (increase in signal amplitude, shift to higher frequencies, etc.). Previous studies have concentrated on behaviourally plastic changes in signal production as a result of elevated background noise levels. To our knowledge, long‐term effects of anthropogenic noise on signal production have not yet been investigated. Moreover, strategies of invertebrate species to ensure acoustic signal transmission under anthropogenic noise have not been examined, so far. We tested whether and how male Chorthippus biguttulus grasshoppers from noisy roadside habitats may adjust acoustic courtship signals to elevated background noise levels, compared with conspecifics from quiet control habitats. In this species, sexually selected male courtship signals serve to attract potential mating partners, which make the undisturbed transmission of signals in habitats with increased background noise levels crucial for male reproductive success. Compared to males from control populations, males from roadside habitats produced songs with a significantly higher local frequency maximum under standardized, quiet recording conditions. This local frequency maximum (in the range of c. 6–9 kHz) overlaps with low‐frequent road noise that has the potential to degrade or mask this part of the signals' frequency spectrum. To our knowledge, this is the first evidence that insects from noisy habitats produce different acoustic signals than conspecifics from quiet habitats, possibly using a more permanent mechanism for signal adjustment than behavioural plasticity, which was found in different bird species adjusting to high background noise levels. Such an effect of anthropogenic noise has not been shown for any invertebrate species before, and our results suggest that similar strategies to avoid degradation or masking by noise (i.e. increase in carrier frequency) are used over a wide range of taxa, including both, vertebrates and invertebrates.

Ultraschall in der Geburtshilfe: Kann der Fötus die Ultraschallwelle hören und die Hitze spüren?

Ultraschall in der Geburtshilfe: Kann der Fötus die Ultraschallwelle hören und die Hitze spüren?

An Empirical Phase-Noise Model for MEMS Oscillators Operating in Nonlinear Regime

Nonlinearity of a silicon resonator can lead to improved phase-noise performance in an oscillator when the phase shift of the sustaining amplifier forces the operating point to a steeper phase-frequency slope. As a result, phase modulation on the oscillator frequency is minimized because the resonator behaves as a high-order phase filter. The effect of the increased filtering translates into phase-noise shaping that reflects superior overall performance. Nonlinear effects in MEMS oscillators can be induced via sufficient driving power, generating low-frequency nonwhite noise processes that need to be considered in a phase-noise description. Since the phase-frequency response is not symmetric for a nonlinear detuned resonator, an empirical model based on power series is proposed to describe its effect in the noise sources and to account for the observed higher effective quality factor of the oscillator, the reduction in the corner frequency, and elevated levels of flicker noise very close-to-carrier. The applicability of the presented phase-noise model is shown for three piezoelectric MEMS oscillators, producing a relative fitting error below 1% in all cases.

High sensitivity and versatility of the DEER experiment on nitroxide radical pairs at Q-band frequencies

Measurement of distances with the Double Electron-Electron Resonance (DEER) experiment at X-band frequencies using a pair of nitroxides as spin labels is a popular biophysical tool for studying function-related conformational dynamics of proteins. The technique is intrinsically highly precise and can potentially access the range from 1.5 to 6-10 nm. However, DEER performance drops strongly when relaxation rates of the nitroxide spin labels are high and available material quantities are low, which is usually the case for membrane proteins reconstituted into liposomes. This leads to elevated noise levels, very long measurement times, reduced precision, and a decrease of the longest accessible distances. Here we quantify the performance improvement that can be achieved at Q-band frequencies (34.5 GHz) using a high-power spectrometer. More than an order of magnitude gain in sensitivity is obtained with a homebuilt setup equipped with a 150 W TWT amplifier by using oversized samples. The broadband excitation enabled by the high power ensures that orientation selection can be suppressed in most cases, which facilitates extraction of distance distributions. By varying pulse lengths, Q-band DEER can be switched between orientationally non-selective and selective regimes. Because of suppression of nuclear modulations from matrix protons and deuterons, analysis of the Q-band data is greatly simplified, particularly in cases of very small DEER modulation depth due to low binding affinity between proteins forming a complex or low labelling efficiency. Finally, we demonstrate that a commercial Q-band spectrometer can be readily adjusted to the high-power operation.

포장노면과 타이어간의 마찰음 분석을 통한 교통소음예측 소프트웨어 개발

고속도로 이용차량의 증가와 함께 차량의 대형화와 고속화로 인해 고속도로 교통 소음레벨이 높아지고 있으며 저소음 포장노면 및 방음시설 설치 요청도 급격하게 증가하고 있다. 따라서 고속도로 교통소음으로 인한 민원예방과 함께 효율적이고 경제적인 소음저감 대책을 수립하기 위해서는 정확한 소음 예측 기술 마련이 필요하다. 본 연구에서는 시험도로에 포설된 다양한 포장노면에 대해서 CPX(Close Proximity Test) 및 Pass-by 소음 계측 방법을 혼용한 소음 계측 데이터를 이용하였고 차종별 단독 주행 시험을 실시하여 차량 및 노면별 음향파워레벨 산정식이 마련된 데이터를 이용하였다. 아울러, 상기 산정식의 정확성을 검증하기 위하여 고속도로 12개 지점에 대한 총 38회의 소음 계측한 데이터를 이용하여 해당 지점에 대한 소음 예측 모델을 구성하여 측정값과 예측값을 비교 평가하였다. 최종적으로 3차원 GUI 기능을 지원하는 도로교통 소음 예측 프로그램 KRON(Korea Road Noise)을 개발하였다. 이와 더불어 각 포장형태별 및 차종별에 따른 소음특성을 분석하였다. Domestic economic development, industrialization, and urbanization have brought along not only increased highway traffic but also elevated traffic noise levels. Thus, it is necessary to accurately predict the traffic noise levels in order to address the public demand of alleviating the noise levels in urban areas. In this study, the method of evaluating the sound power level of road traffic was investigated in terms of considering the types of road surface and vehicle, based on previous researches. Regarding CPX (Close Proximity Test) and Pass-by test, the measured noise data of Test Road of Korea Highway Corporation were utilized in order to construct the database of sound power levels of various vehicles. Specifically, the 38 noise measurement and analysis in 1/1-octave band frequencies at 12 pre-selected sites were carried out, considering topography and road surface. Finally, the comparison study was conducted between predicted and measured data in terms of traffic noise. The traffic noise prediction was based on the KRON (Korea Road Noise) program, which was developed being equipped wit 3-dimensional GUI. In addition, the traffic noise characteristics were evaluated in terms of vehicle types and pavement surface conditions.

The effect of noise on behavior and acoustic communication in the blacktail shiner (Cyprinella venusta).

Despite their seemingly quiet underwater habitat, freshwater fishes are not sheltered from elevated noise levels. Anthropogenic noise along with natural noise sources increase noise levels in aquatic environments. Higher noise levels can result in elevated hearing thresholds and decrease the signal‐to‐noise ratio of acoustic signals. Because many fishes use acoustic signals during critical life history stages, it is important to determine whether elevated noise levels affect behavior or sound production during these stages. This study describes sound production and corresponding behaviors as well as hearing in the black tail shiner (Cyprinella venusta). An attempt was also made to determine the effect of elevated noise levels on acoustic communication and behaviors associated with reproduction and aggression. Behavioral interactions of C. venusta were recorded under noisy and quiet acoustic conditions. Temporal and spectral parameters of the calls as well as the type and number of behaviors performed by the dominant male of each trial were compared between the two conditions to determine if noise affected them. Hearing sensitivity and range were determined using the auditory brainstem response approach.

Measurements of ship noise and calling behavior on bioacoustic probes during opportunistic exposure of blue whales to commercial ship noise.

Bioacoustic probes were deployed on blue whales in and around commercial shipping lanes in Southern California. The proximity of shipping routes to predictable blue whale feeding grounds makes this an ideal location to study the impact of intense low‐frequency noise on whale behavior. The bioacoustic probe is outfitted with a calibrated hydrophone, and records temperature, pressure, and two‐axis acceleration, allowing us to evaluate sound exposure levels in relation to swimming and calling behaviors. During eight tag deployments, large commercial ships came within 1000 m or less of the tagged whale. Received levels of ship noise were measured from the tag to estimate the sound exposure levels. Because of the high level of flow noise recorded on the tag, measurements of ship noise were only possible at minimum velocity and speed. Dive and surface behaviors were evaluated related to the passage of the ship and elevated noise levels. One calling whale was tagged and exposed to ship noise at a close approach; no major change in calling behavior was observed. The results of this research provide insight on blue whale response to ships and highlight some of the challenges when measuring low frequency noise from an attached tag. [This work was supported by the ONR.]

Aperiodicity in the near field of full-scale rotor blade tip vortices

Blade tip vortices are the dominant vortical structures of the helicopter flow field. The inherent complexity of the vortex dynamics has led to an increasing interest in full-scale in situ experiments, where the near field, closely behind the blade, is of particular interest, since measures of vortex control mostly target this initial stage of development. To examine the near field, three-component particle image velocimetry (PIV) measurements of blade tip vortices of a full-scale helicopter in simulated hover flight in ground effect were conducted. A feasible and robust evaluation procedure was developed to minimise the shortcomings of full-scale PIV applications, such as a moderate spatial resolution and an elevated measurement noise level. At vortex ages ranging from $$\psi_{\rm v}=1^{\circ}$$ to 30°, a pronounced aperiodicity and asymmetry of the vortex were observed in -sections perpendicular to the vortex axes. At $$\psi_{\rm v}=1^{\circ}$$ , a preferential orientation of the vortex was observed. For increasing wake age, vortex wandering increased while the asymmetry of the vortex cores decreased. The high level of aperiodicity and core asymmetry must be taken into account when considering phase-averaged vortex characteristics in the near wake region.

Noise levels in an Australian emergency department

Summary Elevated hospital noise levels potentially affect communication, stress levels, aggressive behaviour and sleep during treatment. However, few studies have measured noise in the emergency department (ED). In an Australian context, study investigators aimed to assess noise levels in multiple clinical care areas of the ED. Data was collected in decibels (dB) in six ED patient locations over 24hours. Recorded data was analysed and compared across locations and over time, in the light of World Health Organization (WHO) and Australian noise standards. The 24-hour average sound levels varied between 64.0 and 55.8dB, with some diurnal variation in noise levels, thereby consistently exceeding recommended levels. Such high noise levels could potentially affect patient care and well-being whilst in the ED.

Noise levels in a neonatal transport incubator in medically configured aircraft

Objective The purpose of this study was to evaluate exposure of neonates to noise during air medical transport as few commercially available hearing protective devices exist for premature newborns during air medical transport. Methods Sound pressure levels in an infant incubator during actual flight conditions in four common medically configured aircraft were measured. Three noise dosimeters measured time-weighted average noise exposure during flight in each aircraft. One dosimeter was placed in the infant incubator, and the remaining dosimeters recorded noise levels in various parts of the aircraft cabin. Results The incubator provided a 6-dBA decrease in noise exposure from that in the crew cabin. The average noise level in the incubator in all aircraft was close to 80 dB, much higher than the proposed limits of 45 dB for neonatal intensive care unit noise exposure or 60 dB during transport. Conclusions Exposure of neonates to elevated noise levels during transport may be harmful, and steps should be taken to protect the hearing of this patient population.

A Study of Noise Levels in an Open-Bay ICU

Background: Elevated noise levels are among the top complaints of patients and visitors in US hospitals. Several organizations, including the World Health Organization, have established limits of noise in hospitals. Unfortunately, most hospitals fail to meet these guidelines. The goal of this study was to study noise levels in the surgical intensive care unit at Eisenhower Army Medical Center to determine compliance with standards concerning noise levels and to assess whether the open-bay layout impacted noise levels. Methods: An observational study was performed examining sound pressure levels (Leq) during 3 different times of day. Measurements were taken in occupied and unoccupied patient rooms and with/without patients in adjacent rooms. Measurements were taken in both isolation rooms and open bays. Results: The average Leq was 69.9 dB, higher than the World Health Organization’s standards of 40 dB. The peak decibel readings averaged 82.0 dB. The open-bay rooms were significantly quieter than the isolation rooms. Average noise levels were consistent throughout the day. Conclusions: The ICU exhibited excess noise during all time periods. The open-bay layout resulted in lower noise levels, but overall levels were higher than set limits. Noise reduction strategies must be a part of construction strategy for intensive care units.

Survey of ambient noise in aquariums.

Owning and maintaining an aquarium is a common hobby, but the ambient noise in aquariums resulting from pumps, filters, bubblers, and other equipment is not well studied. Elevated ambient noise levels have been shown to adversely affect wild fish and marine invertebrates, and anecdotal evidence suggests that this may be a problem in aquariums as well. Aquariums designed to maintain coral reefs require high water flow and pristine water conditions, which in turn require pumps and protein skimmers that contribute to underwater noise. A survey of ambient noise in both fresh and saltwater aquariums ranging in size from 5 to 550 gal was conducted. The aquariums differed in construction material, number, size and type of pumps, and presence of other equipment. The ambient noise broadband levels, spectrum levels, and time-frequency representations are compared, and general conclusions are drawn about noise characteristics of equipment and aquariums.